All Publications

@article{marzuca-nassr2024,

title = {Muscle Mass and Strength Gains Following Resistance Exercise Training in Older Adults 65-75 Years and Older Adults above 85 Years},

author = {Gabriel Nasri Marzuca-Nassr and Andrea Alegría-Molina and Yuri SanMartín-Calísto and Macarena Artigas-Arias and Nolberto Huard and Jorge Sapunar and Luis A Salazar and Lex B Verdijk and Luc J C Loon},

doi = {10.1123/ijsnem.2023-0087},

issn = {1543-2742},

year  = {2024},

date = {2024-01-01},

journal = {International journal of sport nutrition and exercise metabolism},

volume = {34},

number = {1},

pages = {11–19},

abstract = {Resistance exercise training (RET) can be applied effectively to increase muscle mass and function in older adults (65-75 years). However, it has been speculated that older adults above 85 years are less responsive to the benefits of RET. This study compares the impact of RET on muscle mass and function in healthy older adults 65-75 years versus older adults above 85 years. We subjected 17 healthy older adults 65-75 years (OLDER 65-75},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{kirmse2024,

title = {Collagen Peptide Supplementation during Training Does Not Further Increase Connective Tissue Protein Synthesis Rates},

author = {Marius Kirmse and Theo Maria Lottmann and Nicola Reiner Volk and Markus Marées and Andrew M. Holwerda and Luc J. C. Loon and Petra Platen},

doi = {10.1249/MSS.0000000000003519},

issn = {0195-9131},

year  = {2024},

date = {2024-01-01},

journal = {Medicine and Science in Sports and Exercise},

abstract = {Introduction: Protein supplementation increases post-exercise muscle protein synthesis rates and, as such, supports exercise-induced muscle conditioning. Collagen protein has been suggested as the preferred protein source to stimulate muscle connective protein synthesis rates during recovery from exercise. Here we assessed the effects of hydrolyzed collagen peptide supplementation on both myofibrillar as well as muscle connective protein synthesis rates during one week of strenuous resistance exercise training. Methods: In a randomized, double-blind, parallel design, 25 young men (24±3 y, 76.9±6.4 kg) were selected to perform one week of intense resistance-type exercise training. Subjects were randomly assigned into two groups receiving either 15 g hydrolyzed collagen peptides (COL) or a non-caloric placebo (PLA) twice daily during the intervention. Subjects were administered deuterated water (2H2O) daily, with blood and skeletal muscle tissue samples being collected prior to and after the intervention to determine daily myofibrillar and muscle connective protein synthesis rates. Results: Post-absorptive plasma glycine, proline, and hydroxyproline concentrations increased following collagen peptide supplementation (p$<$0.05) and showed higher levels when compared to the placebo group (p$<$0.05). Daily muscle connective protein synthesis rates during the intervention period exceeded myofibrillar protein synthesis rates (1.99±0.38 versus 1.34±0.23 %/d, respectively; p$<$0.001). Collagen peptide supplementation did not result in higher myofibrillar or muscle connective protein synthesis rates (1.34±0.19 and 1.97±0.47 %/d, respectively) when compared to the placebo group (1.34±0.27 and 2.00±0.27 %/d, respectively; p$>$0.05). Conclusions: Collagen peptide supplementation (2 x 15 g daily) does not increase myofibrillar or muscle connective protein synthesis rates during one week of intense resistance exercise training in young, recreational athletes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{houben2024,

title = {Benefits of Resistance Training Are Not Preserved after Cessation of Supervised Training in Prostate Cancer Patients on Androgen Deprivation Therapy},

author = {Lisanne H. P. Houben and Maarten Overkamp and Joan M. G. Senden and Joep G. H. Roermund and Peter Vries and Kevin Laet and Saskia Meer and Luc J. C. Loon and Milou Beelen and Sandra Beijer},

doi = {10.1002/ejsc.12050},

issn = {1746-1391},

year  = {2024},

date = {2024-01-01},

journal = {European Journal of Sport Science},

volume = {24},

number = {1},

pages = {116–126},

abstract = {Resistance exercise training is effective to counteract the adverse effects of androgen deprivation therapy (ADT) on body composition, muscle mass and leg strength in prostate cancer patients (PCa). However, it is unknown whether these effects can be autonomously maintained after cessation of the supervised program. Sixty-eight PCa patients on ADT were included. The exercise intervention group (EX},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{brinkmans2024,

title = {Energy Expenditure and Dietary Intake in Professional Female Football Players in the Dutch Women's League: Implications for Nutritional Counselling},

author = {Naomi Brinkmans and Guy Plasqui and Luc Loon and Jan-Willem Dijk},

doi = {10.1080/02640414.2024.2329850},

issn = {0264-0414},

year  = {2024},

date = {2024-01-01},

journal = {Journal of Sports Sciences},

volume = {42},

number = {4},

pages = {313–322},

abstract = {In contrast to male football players, research on the nutritional requirements of female football players is limited. This study aimed to assess total daily energy expenditure (TDEE) in professional female football players, along with body composition, physical activity and dietary intake. This observational study included 15 professional football players playing in the highest Dutch Women's League. TDEE was assessed by doubly labelled water over 14 days, along with resting metabolic rate (RMR; ventilated hood), fat-free mass (FFM; dual-energy x-ray absorptiometry), and dietary intake (24-h recalls). Physical activity energy expenditure (PAEE) was derived from subtracting RMR and estimated diet-induced thermogenesis (10%) from TDEE. TDEE was 2882 ± 278 kcal/day (58 ± 5 kcal/kg FFM) and significantly (p $<$ 0.05) correlated with FFM (r = 0.62). PAEE was 1207 ± 213 kcal/d. Weighted energy intake was 2344 kcal [2023–2589]. Carbohydrate intakes were 3.2 ± 0.7, 4.4 ± 1.1 and 5.3 ± 1.9 g/kg body mass for rest, training and match days, respectively, while weighted mean protein intake was 1.9 ± 0.4 g/kg body mass. In conclusion, the energy requirements of professional female football players are moderate to high and can be explained by the substantial PAEE. To fuel these requirements, sports nutritionists should consider shifting the players' focus towards prioritizing adequate carbohydrate intakes, rather than emphasizing high protein consumption.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{betz2024,

title = {Type II Muscle Fiber Capillarization Is an Important Determinant of Post-Exercise Microvascular Perfusion in Older Adults},

author = {Milan W Betz and Floris K Hendriks and Alfons J H M Houben and Mathias D G Eynde and Lex B Verdijk and Luc J C Loon and Tim Snijders},

doi = {10.1159/000535831},

issn = {1423-0003},

year  = {2024},

date = {2024-01-01},

journal = {Gerontologia},

volume = {70},

number = {3},

pages = {290–301},

abstract = {INTRODUCTION: Microvascular perfusion is essential for post-exercise skeletal muscle recovery to ensure adequate delivery of nutrients and growth factors. This study assessed the relationship between various indices of muscle fiber capillarization and microvascular perfusion assessed by contrast-enhanced ultrasound (CEUS) at rest and during recovery from a bout of resistance exercise in older adults.nnMETHODS: Sixteen older adults (72 ± 6 y, 5/11 male/female) participated in an experimental test day during which a muscle biopsy was collected from the vastus lateralis and microvascular perfusion was determined by CEUS at rest and at 10 and 40 min following a bout of resistance exercise. Immunohistochemistry was performed on muscle tissue samples to determine various indices of both mixed and fiber-type-specific muscle fiber capillarization.nnRESULTS: Microvascular blood volume at t = 10 min was higher compared with rest and t = 40 min (27.2 ± 4.7 vs. 3.9 ± 4.0 and 7.0 ± 4.9 AU, respectively, both p < 0.001). Microvascular blood volume at t = 40 min was higher compared with rest (p < 0.001). No associations were observed between different indices of mixed muscle fiber capillarization and microvascular blood volume at rest and following exercise. A moderate (r = 0.59, p < 0.05) and strong (r = 0.81, p < 0.001) correlation was observed between type II muscle fiber capillary-to-fiber ratio and the microvascular blood volume increase from rest to t = 10 and t = 40 min, respectively. In addition, type II muscle fiber capillary contacts and capillary-to-fiber perimeter exchange index were strongly correlated with the microvascular blood volume increase from rest to t = 40 min (r = 0.66, p < 0.01 and r = 0.64, p < 0.01, respectively).nnCONCLUSION: Resistance exercise strongly increases microvascular blood volume for at least 40 min after exercise cessation in older adults. This resistance exercise-induced increase in microvascular blood volume is strongly associated with type II muscle fiber capillarization in older adults.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{trommelen2023,

title = {The Anabolic Response to Protein Ingestion during Recovery from Exercise Has No Upper Limit in Magnitude and Duration in Vivo in Humans},

author = {Jorn Trommelen and Glenn A A Lieshout and Jean Nyakayiru and Andrew M Holwerda and Joey S J Smeets and Floris K Hendriks and Janneau M X Kranenburg and Antoine H Zorenc and Joan M Senden and Joy P B Goessens and Annemie P Gijsen and Luc J C Loon},

doi = {10.1016/j.xcrm.2023.101324},

issn = {2666-3791},

year  = {2023},

date = {2023-12-01},

journal = {Cell reports. Medicine},

volume = {4},

number = {12},

pages = {101324},

abstract = {The belief that the anabolic response to feeding during postexercise recovery is transient and has an upper limit and that excess amino acids are being oxidized lacks scientific proof. Using a comprehensive quadruple isotope tracer feeding-infusion approach, we show that the ingestion of 100 g protein results in a greater and more prolonged (¿12 h) anabolic response when compared to the ingestion of 25 g protein. We demonstrate a dose-response increase in dietary-protein-derived plasma amino acid availability and subsequent incorporation into muscle protein. Ingestion of a large bolus of protein further increases whole-body protein net balance, mixed-muscle, myofibrillar, muscle connective, and plasma protein synthesis rates. Protein ingestion has a negligible impact on whole-body protein breakdown rates or amino acid oxidation rates. These findings demonstrate that the magnitude and duration of the anabolic response to protein ingestion is not restricted and has previously been underestimated in vivo in humans.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hendriks2023,

title = {Trabecular, but Not Cortical, Bone Tissue Protein Synthesis Rates Are Lower in the Femoral Head When Compared to the Proximal Femur Following an Intracapsular Hip Fracture},

author = {Floris K Hendriks and Michelle E G Weijzen and Joy P B Goessens and Antoine H G Zorenc and Annemie P Gijsen and Irene Fleur Kramer and Joop P W Bergh and Martijn Poeze and Taco J Blokhuis and Luc J C Loon},

doi = {10.1016/j.bone.2023.116921},

issn = {1873-2763},

year  = {2023},

date = {2023-12-01},

journal = {Bone},

volume = {177},

pages = {116921},

abstract = {BACKGROUND: All musculoskeletal tissues are in a constant state of turnover, with a dynamic equilibrium between tissue protein synthesis and breakdown rates. The synthesis of protein allows musculoskeletal tissues to heal following injury. Yet, impaired tissue healing is observed following certain injuries, such as geriatric hip fractures. It is assumed that the regenerative properties of femoral head bone tissue are compromised following an intracapsular hip fracture and therefore hip replacement surgery is normally performed. However, the actual impact on in vivo bone protein synthesis rates has never been determined.nnDESIGN: In the present study, 10 patients (age: 79 ± 10 y, BMI: 24 ± 4 kg/m) with an acute (¡24 h) intracapsular hip fracture received a primed continuous intravenous infusion of L-[ring-C]-phenylalanine before and throughout their hip replacement surgery. Trabecular and cortical bone tissue from both the femoral head and proximal femur were sampled during surgery to assess protein synthesis rates of affected (femoral head) and unaffected (proximal femur) bone tissue, respectively. In addition, tissue samples of gluteus maximus muscle, synovium, ligamentum teres, and femoral head cartilage were collected. Tissue-specific protein synthesis rates were assessed by measuring L-[ring-C]-phenylalanine incorporation in tissue protein.nnRESULTS: Femoral head trabecular bone protein synthesis rates (0.056 [0.024-0.086] %/h) were lower when compared to proximal femur trabecular bone protein synthesis rates (0.081 [0.056-0.118] %/h; P = 0.043). Cortical bone protein synthesis rates did not differ between the femoral head and proximal femur (0.041 [0.021-0.078] and 0.045 [0.028-0.073] %/h, respectively; P ¿ 0.05). Skeletal muscle, synovium, ligamentum teres, and femoral head cartilage protein synthesis rates averaged 0.080 [0.048-0.089], 0.093 [0.051-0.130], 0.121 [0.110-0.167], and 0.023 [0.015-0.039] %/h, respectively.nnCONCLUSION: In contrast to the general assumption that the femoral head is avital after an intracapsular displaced hip fracture in the elderly, our data show that bone protein synthesis is still ongoing in femoral head bone tissue during the early stages following an intracapsular hip fracture in older patients. Nonetheless, trabecular bone protein synthesis rates are lower in the femoral head when compared to the proximal femur in older patients following an acute intracapsular hip fracture. Trial register no: NL9036.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{philippejmpinckaers2023,

title = {Higher Muscle Protein Synthesis Rates Following Ingestion of an Omnivorous Meal Compared with an Isocaloric and Isonitrogenous Vegan Meal in Healthy, Older Adults},

author = {Philippe J M Pinckaers and Jacintha Domić and Heather L. Petrick and Andrew M. Holwerda and Jorn Trommelen and Floris K. Hendriks and Lisanne H P Houben and Joan M. Senden and Janneau M X Kranenburg and Lisette C. P. G. M. Groot and Lex B. Verdijk and Tim Snijders and Luc J. C. Loon},

doi = {10.1016/j.tjnut.2023.11.004},

year  = {2023},

date = {2023-11-01},

abstract = {Plant-derived proteins are considered to have lesser anabolic properties when compared with animal-derived proteins. The anabolic properties of isolated proteins do not necessarily reflect the anabolic response to the ingestion of whole-foods. The presence or absence of the various components that constitute the whole-food matrix can strongly impact protein digestion and amino acid absorption and, as such, modulate post-prandial muscle protein synthesis rates. So far, no study has compared the anabolic response following ingestion of an omnivorous versus a vegan meal. To compare post-prandial muscle protein synthesis rates following ingestion of a whole-food meal providing 100 g lean ground beef versus an isonitrogenous, isocaloric whole-food plant-based meal in healthy, older adults. In a randomized, counter-balanced, cross-over design, 16 older (65–85 y) adults (8 males, 8 females) underwent 2 test days. On one day, participants consumed a whole-food omnivorous meal containing beef as the primary source of protein (0.45 g protein$bullet$kg-1 BM; MEAT). On the other day, participants consumed an isonitrogenous and isocaloric whole-food vegan meal containing unprocessed plant-based whole-foods (PLANT). Primed continuous L-[ring-13C6]-phenylalanine infusions were applied with blood and muscle biopsies being collected frequently for 6 h to assess post-prandial plasma amino acid profiles and muscle protein synthesis rates. Data are presented as means±SDs and were analyzed by two way-repeated measures ANOVA and paired-samples t-tests. MEAT increased plasma essential amino acid concentrations more than PLANT over the 6 h post-prandial period (incremental area under curve 87±37 vs 38±54 mmol$bullet$6 h$bullet$L-1 respectively; P-interaction$<$0.01). Ingestion of MEAT resulted in $sim$47% higher post-prandial muscle protein synthesis rates when compared to the ingestion of PLANT (0.052±0.023 and 0.035±0.021 %$bullet$h-1, respectively; paired-samples t-test: P=0.037). Ingestion of a whole-food meal containing beef, results in greater post-prandial muscle protein synthesis rates when compared to the ingestion of an isonitrogenous whole-food plant-based meal in older adults. https://clinicaltrials.gov/study/NCT05151887. Https://clinicaltrials.gov/study/NCT05151887},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36574223,

title = {Observations of Nemaline Bodies in Muscle Biopsies of Critically Ill Patients Infected with SARS-CoV-2},

author = {Frank Vandenabeele and Sjoerd Stevens and Tim Snijders and Björn Stessel and Jasperina Dubois and Luc J C Loon and Ivo Lambrichts and Anouk Agten},

doi = {10.1093/jmicro/dfac072},

issn = {2050-5701},

year  = {2023},

date = {2023-10-01},

journal = {Microscopy (Oxford, England)},

volume = {72},

number = {5},

pages = {388–394},

abstract = {Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who have been admitted to the intensive care unit (ICU) often face months of physical disability after discharge. To optimize recovery, it is important to understand the role of musculoskeletal alterations in critically ill patients infected with SARS-CoV-2. The main aim of the present study was to describe the presence and morphology of nemaline bodies found in the skeletal muscle tissue from critically ill patients infected with SARS-CoV-2. In n = 7 patients infected with SARS-CoV-2, ultrastructural characteristics of vastus lateralis muscle obtained on days 1-3 and days 5-8 following ICU admission were investigated in more detail with electron microscopy. Those muscle biopsies consistently showed variable degrees of myofiber necrosis and myofibrillar disorganization. In 4/7 (57%) patients on days 5-8, the Z-line material accumulated into nemaline bodies with a typical lattice-like appearance at higher magnification, similar to that found in nemaline myopathy. This study is the first to describe the disintegration of myofibrils and the accumulation of Z-line material into nemaline bodies in the skeletal muscle tissue obtained from critically ill coronavirus disease-19 patients following ICU admission, which should be interpreted primarily as a non-specific pathological response of extreme myofibrillar disintegration associated with myofiber necrosis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{aussieker2023,

title = {Collagen Protein Ingestion during Recovery from Exercise Does Not Increase Muscle Connective Protein Synthesis Rates},

author = {Thorben Aussieker and Luuk Hilkens and Andrew M Holwerda and Cas J Fuchs and Lisanne H P Houben and Joan M Senden and Jan-Willem VAN Dijk and Tim Snijders and Luc J C VAN Loon},

doi = {10.1249/MSS.0000000000003214},

issn = {1530-0315},

year  = {2023},

date = {2023-10-01},

journal = {Medicine and science in sports and exercise},

volume = {55},

number = {10},

pages = {1792–1802},

abstract = {INTRODUCTION: Protein ingestion during recovery from exercise has been reported to augment myofibrillar protein synthesis rates, without increasing muscle connective protein synthesis rates. It has been suggested that collagen protein may be effective in stimulating muscle connective protein synthesis. The present study assessed the capacity of both whey and collagen protein ingestion to stimulate postexercise myofibrillar and muscle connective protein synthesis rates.nnMETHODS: In a randomized, double-blind, parallel design, 45 young male ( n = 30) and female ( n = 15) recreational athletes (age, 25 ± 4 yr; body mass index, 24.1 ± 2.0 kg$cdot$m -2 ) were selected to receive primed continuous intravenous infusions with l -[ring- 13 C 6 ]-phenylalanine and l -[3,5- 2 H 2 ]-tyrosine. After a single session of resistance type exercise, subjects were randomly allocated to one of three groups ingesting either 30 g whey protein (WHEY},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37348850,

title = {The Postprandial Plasma Amino Acid Response Does Not Differ Following the Ingestion of a Solid versus a Liquid Milk Protein Product in Healthy Adult Females},

author = {Glenn A A Lieshout and Jorn Trommelen and Jean Nyakayiru and Janneau Kranenburg and Joan M Senden and Lex B Verdijk and Luc J C Loon},

doi = {10.1123/ijsnem.2023-0038},

issn = {1543-2742},

year  = {2023},

date = {2023-09-01},

journal = {International journal of sport nutrition and exercise metabolism},

volume = {33},

number = {5},

pages = {247–254},

abstract = {Dietary protein digestion and amino acid absorption rates are modulated by numerous factors such as the food matrix. It has been speculated that protein ingested in liquid form is more rapidly digested and absorbed when compared with ingestion in solid form. Here, we assessed the postprandial plasma amino acid availability following ingestion of a single bolus of protein provided in either liquid or solid form. Twelve healthy, young females were included in this randomized cross-over study. On two separate test days, participants ingested 20-g milk protein concentrate in solid form (protein bar) or in liquid form (protein drink). Products were composed of matched ingredients and, thereby, had the same macro- and micronutrient composition. On both test days, arterialized blood samples were collected at regular time intervals for up to 4 hr following protein ingestion to assess the postprandial rise in plasma amino acid concentrations. Protein ingestion robustly elevated circulating plasma amino acid concentrations (p ¡ .001), with no significant differences between treatments (p = .088). The incremental area under the curve of the postprandial rise in total plasma amino acid concentrations did not differ following bar versus drink consumption (160 ± 73 vs. 160 ± 71 mmol$cdot$L-1$cdot$240 min-1, respectively; 95% confidence interval [-37, 37]; Cohen's dz = 0.003; p = .992). Ingestion of protein in liquid or solid form does not modulate postprandial amino acid availability in healthy, female adults. Any differences in protein digestion and amino acid absorption due to differences in food matrix are not attributed to the protein being consumed as a bar or as a drink.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37161470,

title = {Resistance Exercise Counteracts the Impact of Androgen Deprivation Therapy on Muscle Characteristics in Cancer Patients},

author = {Maarten Overkamp and Lisanne H P Houben and Thorben Aussieker and Janneau M X Kranenburg and Philippe J M Pinckaers and Ulla R Mikkelsen and Milou Beelen and Sandra Beijer and Luc J C Loon and Tim Snijders},

doi = {10.1210/clinem/dgad245},

issn = {1945-7197},

year  = {2023},

date = {2023-09-01},

journal = {The Journal of clinical endocrinology and metabolism},

volume = {108},

number = {10},

pages = {e907–e915},

abstract = {CONTEXT: Androgen deprivation therapy (ADT) forms the cornerstone in prostate cancer (PCa) treatment. However, ADT also lowers skeletal muscle mass.nnOBJECTIVE: To identify the impact of ADT with and without resistance exercise training on muscle fiber characteristics in PCa patients.nnMETHODS: Twenty-one PCa patients (72 ± 6 years) starting ADT were included. Tissue samples from the vastus lateralis muscle were assessed at baseline and after 20 weeks of usual care (n = 11) or resistance exercise training (n = 10). Type I and II muscle fiber distribution, fiber size, and myonuclear and capillary contents were determined by immunohistochemistry.nnRESULTS: Significant decreases in type I (from 7401 ± 1183 to 6489 ± 1293 μm2, P ¡ .05) and type II (from 6225 ± 1503 to 5014 ± 714 μm2, P ¡ .05) muscle fiber size were observed in the usual care group. In addition, type I and type II individual capillary-to-fiber ratio (C/Fi) declined (-12% ± 12% and -20% ± 21%, respectively, P ¡ .05). In contrast, significant increases in type I (from 6700 ± 1464 to 7772 ± 1319 μm2, P ¡ .05) and type II (from 5248 ± 892 to 6302 ± 1385 μm2, P ¡ .05) muscle fiber size were observed in the training group, accompanied by an increase in type I and type II muscle fiber myonuclear contents (+24% ± 33% and +21% ± 23%, respectively, P ¡ .05) and type I C/Fi (+18% ± 14%, P ¡ .05).nnCONCLUSION: The onset of ADT is followed by a decline in both type I and type II muscle fiber size and capillarization in PCa patients. Resistance exercise training offsets the negative impact of ADT and increases type I and II muscle fiber size and type I muscle fiber capillarization in these patients.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{florisk.hendriks2023,

title = {Branched-Chain Ketoacid Co-Ingestion with Protein Lowers Amino Acid Oxidation during Hemodialysis: A Randomized Controlled Cross-over Trial},

author = {Floris K. Hendriks and Jorn Trommelen and Frank M. Sande and Janneau M X Kranenburg and Jeffrey H. W. Kuijpers and Dion C. J. Houtvast and Guus H. J. Jetten and Joy P B Goessens and Steven J. R. Meex and Jeroen P. Kooman and Luc J. C. Loon},

doi = {10.1016/j.clnu.2023.06.034},

year  = {2023},

date = {2023-08-01},

volume = {42},

number = {8},

pages = {1436–1444},

abstract = {Hemodialysis removes amino acids from the circulation, thereby stimulating muscle proteolysis. Protein ingestion during hemodialysis can compensate for amino acid removal but may also increase uremic toxin production. Branched-chain ketoacid (BCKA) co-ingestion may provide an additional anabolic stimulus without adding to uremic toxin accumulation. In the present study we assessed the impact of BCKA co-ingestion with protein on forearm amino acid balance and amino acid oxidation during hemodialysis.Nine patients (age: 73 ± 10 y) on chronic hemodialysis participated in this crossover trial. During two 4-h hemodialysis sessions, patients ingested 18 g protein with (PRO + BCKA) or without (PRO) 9 g BCKAs in a randomized order. Test beverages were labeled with L-[ring-13C6]-phenylalanine and provided throughout the last 3 h of hemodialysis as 18 equal sips consumed with 10-min intervals. Arterial and venous plasma as well as breath samples were collected frequently throughout hemodialysis.Arterial plasma total amino acid (TAA) concentrations during PRO and PRO + BCKA treatments were significantly lower after 1 h of hemodialysis (2.6 ± 0.3 and 2.6 ± 0.3 mmol/L, respectively) when compared to pre-hemodialysis concentrations (4.2 ± 1.0 and 4.0 ± 0.5 mmol/L, respectively; time effect: P $<$ 0.001). Arterial plasma TAA concentrations increased throughout test beverage ingestion (time effect: P = 0.027) without differences between treatments (time$ast$treatment: P = 0.62). Forearm arteriovenous TAA balance during test beverage ingestion did not differ between timepoints (time effect: P = 0.31) or treatments (time$ast$treatment: P = 0.34). Whole-body phenylalanine oxidation was 33 ± 16% lower during PRO + BCKA when compared to PRO treatments (P $<$ 0.001).BCKA co-ingestion with protein during hemodialysis does not improve forearm net protein balance but lowers amino acid oxidation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37185454,

title = {Acute Ketone Monoester Supplementation Impairs 20-Min Time-Trial Performance in Trained Cyclists: A Randomized, Crossover Trial},

author = {Devin G McCarthy and Jack Bone and Matthew Fong and Phillippe J M Pinckaers and William Bostad and Douglas L Richards and Luc J C Loon and Martin J Gibala},

doi = {10.1123/ijsnem.2022-0255},

issn = {1543-2742},

year  = {2023},

date = {2023-07-01},

journal = {International journal of sport nutrition and exercise metabolism},

volume = {33},

number = {4},

pages = {181–188},

abstract = {Acute ketone monoester (KE) supplementation can alter exercise responses, but the performance effect is unclear. The limited and equivocal data to date are likely related to factors including the KE dose, test conditions, and caliber of athletes studied. We tested the hypothesis that mean power output during a 20-min cycling time trial (TT) would be different after KE ingestion compared to a placebo (PL). A sample size of 22 was estimated to provide 80% power to detect an effect size dz of 0.63 at an alpha level of .05 with a two-tailed paired t test. This determination considered 2.0% as the minimal important difference in performance. Twenty-three trained cyclists (N = 23; peak oxygen uptake: 65 ± 12 ml$cdot$kg-1 min-1; M ± SD), who were regularly cycling ¿5 hr/week, completed a familiarization trial followed by two experimental trials. Participants self-selected and replicated their diet and exercise for $sim$24 hr before each trial. Participants ingested either 0.35 g/kg body mass of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate KE or a flavor-matched PL 30 min before exercise in a randomized, triple-blind, crossover manner. Exercise involved a 15-min warm-up followed by the 20-min TT on a cycle ergometer. The only feedback provided was time elapsed. Preexercise venous [β-hydroxybutyrate] was higher after KE versus PL (2.0 ± 0.6 vs. 0.2 ± 0.1 mM, p ¡ .0001). Mean TT power output was 2.4% (0.6% to 4.1%; mean [95% confidence interval]) lower after KE versus PL (255 ± 54 vs. 261 ± 54 W, p ¡ .01; dz = 0.60). The mechanistic basis for the impaired TT performance after KE ingestion under the present study conditions remains to be determined.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36857005,

title = {Pre-Sleep Protein Ingestion Increases Mitochondrial Protein Synthesis Rates during Overnight Recovery from Endurance Exercise: A Randomized Controlled Trial},

author = {Jorn Trommelen and Glenn A A Lieshout and Pardeep Pabla and Jean Nyakayiru and Floris K Hendriks and Joan M Senden and Joy P B Goessens and Janneau M X Kranenburg and Annemie P Gijsen and Lex B Verdijk and Lisette C P G M Groot and Luc J C Loon},

doi = {10.1007/s40279-023-01822-3},

issn = {1179-2035},

year  = {2023},

date = {2023-07-01},

journal = {Sports medicine (Auckland, N.Z.)},

volume = {53},

number = {7},

pages = {1445–1455},

abstract = {BACKGROUND: Casein protein ingestion prior to sleep has been shown to increase myofibrillar protein synthesis rates during overnight sleep. It remains to be assessed whether pre-sleep protein ingestion can also increase mitochondrial protein synthesis rates. Though it has been suggested that casein protein may be preferred as a pre-sleep protein source, no study has compared the impact of pre-sleep whey versus casein ingestion on overnight muscle protein synthesis rates.nnOBJECTIVE: We aimed to assess the impact of casein and whey protein ingestion prior to sleep on mitochondrial and myofibrillar protein synthesis rates during overnight recovery from a bout of endurance-type exercise.nnMETHODS: Thirty-six healthy young men performed a single bout of endurance-type exercise in the evening (19:45 h). Thirty minutes prior to sleep (23:30 h), participants ingested 45 g of casein protein, 45 g of whey protein, or a non-caloric placebo. Continuous intravenous L-[ring-C]-phenylalanine infusions were applied, with blood and muscle tissue samples being collected to assess overnight mitochondrial and myofibrillar protein synthesis rates.nnRESULTS: Pooled protein ingestion resulted in greater mitochondrial (0.087 ± 0.020 vs 0.067 ± 0.016%$cdot$h},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36812497,

title = {Dietary Nitrate and Corresponding Gut Microbiota Prevent Cardiac Dysfunction in Obese Mice},

author = {Heather L Petrick and Leslie M Ogilvie and Henver S Brunetta and Avery Robinson and Aleah J Kirsh and Pierre-Andre Barbeau and Rachel M Handy and Bridget Coyle-Asbil and Connor Gianetto-Hill and Kaitlyn M J H Dennis and Luc J C Loon and Adrian Chabowski and Jonathan D Schertzer and Emma Allen-Vercoe and Jeremy A Simpson and Graham P Holloway},

doi = {10.2337/db22-0575},

issn = {1939-327X},

year  = {2023},

date = {2023-07-01},

journal = {Diabetes},

volume = {72},

number = {7},

pages = {844–856},

abstract = {Impaired heart function can develop in individuals with diabetes in the absence of coronary artery disease or hypertension, suggesting mechanisms beyond hypertension/increased afterload contribute to diabetic cardiomyopathy. Identifying therapeutic approaches that improve glycemia and prevent cardiovascular disease are clearly required for clinical management of diabetes-related comorbidities. Since intestinal bacteria are important for metabolism of nitrate, we examined whether dietary nitrate and fecal microbial transplantation (FMT) from nitrate-fed mice could prevent high-fat diet (HFD)-induced cardiac abnormalities. Male C57Bl/6N mice were fed a low-fat diet (LFD), HFD, or HFD+Nitrate (4 mmol/L sodium nitrate) for 8 weeks. HFD-fed mice presented with pathological left ventricle (LV) hypertrophy, reduced stroke volume, and increased end-diastolic pressure, in association with increased myocardial fibrosis, glucose intolerance, adipose inflammation, serum lipids, LV mitochondrial reactive oxygen species (ROS), and gut dysbiosis. In contrast, dietary nitrate attenuated these detriments. In HFD-fed mice, FMT from HFD+Nitrate donors did not influence serum nitrate, blood pressure, adipose inflammation, or myocardial fibrosis. However, microbiota from HFD+Nitrate mice decreased serum lipids, LV ROS, and similar to FMT from LFD donors, prevented glucose intolerance and cardiac morphology changes. Therefore, the cardioprotective effects of nitrate are not dependent on reducing blood pressure, but rather mitigating gut dysbiosis, highlighting a nitrate-gut-heart axis.nnARTICLE HIGHLIGHTS: Identifying therapeutic approaches that prevent cardiometabolic diseases are clearly important, and nitrate represents one such potential compound given its multifactorial metabolic effects. We aimed to determine whether nitrate could prevent high-fat diet (HFD)-induced cardiac abnormalities and whether this was dependent on the gut microbiome. Dietary nitrate attenuated HFD-induced pathological changes in cardiac remodelling, left ventricle reactive oxygen species, adipose inflammation, lipid homeostasis, glucose intolerance, and gut dysbiosis. Fecal microbial transplantation from nitrate-fed mice also prevented serum dyslipidemia, left ventricle reactive oxygen species, glucose intolerance, and cardiac dysfunction. Therefore, the cardioprotective effects of nitrate are related to mitigating gut dysbiosis, highlighting a nitrate-gut-heart axis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37293995,

title = {Dietary Nitrate Preserves Mitochondrial Bioenergetics and Mitochondrial Protein Synthesis Rates during Short-Term Immobilization in Mice},

author = {Heather L Petrick and Rachel M Handy and Bayley Vachon and Sara M Frangos and Andrew M Holwerda and Annemarie P Gijsen and Joan M Senden and Luc J C Loon and Graham P Holloway},

doi = {10.1113/JP284701},

issn = {1469-7793},

year  = {2023},

date = {2023-06-01},

journal = {The Journal of physiology},

abstract = {Skeletal muscle disuse reduces muscle protein synthesis rates and induces atrophy, events associated with decreased mitochondrial respiration and increased reactive oxygen species. Given that dietary nitrate can improve mitochondrial bioenergetics, we examined whether nitrate supplementation attenuates disuse-induced impairments in mitochondrial function and muscle protein synthesis rates. Female C57Bl/6N mice were subjected to single-limb casting (3 or 7 days) and consumed drinking water with or without 1 mM sodium nitrate. Compared with the contralateral control limb, 3 days of immobilization lowered myofibrillar fractional synthesis rates (FSR, P ¡ 0.0001), resulting in muscle atrophy. Although FSR and mitophagy-related proteins were higher in subsarcolemmal (SS) compared with intermyofibrillar (IMF) mitochondria, immobilization for 3 days decreased FSR in both SS (P = 0.009) and IMF (P = 0.031) mitochondria. Additionally, 3 days of immobilization reduced maximal mitochondrial respiration, decreased mitochondrial protein content, and increased maximal mitochondrial reactive oxygen species emission, without altering mitophagy-related proteins in muscle homogenate or isolated mitochondria (SS and IMF). Although nitrate consumption did not attenuate the decline in muscle mass or myofibrillar FSR, intriguingly, nitrate completely prevented immobilization-induced reductions in SS and IMF mitochondrial FSR. In addition, nitrate prevented alterations in mitochondrial content and bioenergetics after both 3 and 7 days of immobilization. However, in contrast to 3 days of immobilization, nitrate did not prevent the decline in SS and IMF mitochondrial FSR after 7 days of immobilization. Therefore, although nitrate supplementation was not sufficient to prevent muscle atrophy, nitrate may represent a promising therapeutic strategy to maintain mitochondrial bioenergetics and transiently preserve mitochondrial protein synthesis rates during short-term muscle disuse. KEY POINTS: Alterations in mitochondrial bioenergetics (decreased respiration and increased reactive oxygen species) are thought to contribute to muscle atrophy and reduced protein synthesis rates during muscle disuse. Given that dietary nitrate can improve mitochondrial bioenergetics, we examined whether nitrate supplementation could attenuate immobilization-induced skeletal muscle impairments in female mice. Dietary nitrate prevented short-term (3 day) immobilization-induced declines in mitochondrial protein synthesis rates, reductions in markers of mitochondrial content, and alterations in mitochondrial bioenergetics. Despite these benefits and the preservation of mitochondrial content and bioenergetics during more prolonged (7 day) immobilization, nitrate consumption did not preserve skeletal muscle mass or myofibrillar protein synthesis rates. Overall, although dietary nitrate did not prevent atrophy, nitrate supplementation represents a promising nutritional approach to preserve mitochondrial function during muscle disuse.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37277162,

title = {Vicia Faba Peptide Network Supplementation Does Not Differ from Milk Protein in Modulating Changes in Muscle Size during Short-Term Immobilization and Subsequent Remobilization, but Increases Muscle Protein Synthesis Rates during Remobilization in Healthy Young Men},

author = {Michelle E G Weijzen and Andrew M Holwerda and Guus H J Jetten and Lisanne H P Houben and Alish Kerr and Heidi Davis and Brian Keogh and Nora Khaldi and Lex B Verdijk and Luc J C Loon},

doi = {10.1016/j.tjnut.2023.01.014},

issn = {1541-6100},

year  = {2023},

date = {2023-06-01},

journal = {The Journal of nutrition},

volume = {153},

number = {6},

pages = {1718–1729},

abstract = {BACKGROUND: Muscle mass and strength decrease during short periods of immobilization and slowly recover during remobilization. Recent artificial intelligence applications have identified peptides that appear to possess anabolic properties in in vitro assays and murine models.nnOBJECTIVES: This study aimed to compare the impact of Vicia faba peptide network compared with milk protein supplementation on muscle mass and strength loss during limb immobilization and regain during remobilization.nnMETHODS: Thirty young (24 ± 5 y) men were subjected to 7 d of one-legged knee immobilization followed by 14 d of ambulant recovery. Participants were randomly allocated to ingest either 10 g of the Vicia faba peptide network (NPN$_1$; n = 15) or an isonitrogenous control (milk protein concentrate; MPC; n = 15) twice daily throughout the study. Single-slice computed tomography scans were performed to assess quadriceps cross-sectional area (CSA). Deuterium oxide ingestion and muscle biopsy sampling were applied to measure myofibrillar protein synthesis rates.nnRESULTS: Leg immobilization decreased quadriceps CSA (primary outcome) from 81.9 ± 10.6 to 76.5 ± 9.2 cm and from 74.8 ± 10.6 to 71.5 ± 9.8 cm in the NPN$_1$ and MPC groups, respectively (P ¡ 0.001). Remobilization partially recovered quadriceps CSA (77.3 ± 9.3 and 72.6 ± 10.0 cm, respectively; P = 0.009), with no differences between the groups (P ¿ 0.05). During immobilization, myofibrillar protein synthesis rates (secondary outcome) were lower in the immobilized leg (1.07% ± 0.24% and 1.10% ± 0.24%/d, respectively) than in the non-immobilized leg (1.55% ± 0.27% and 1.52% ± 0.20%/d, respectively; P ¡ 0.001), with no differences between the groups (P ¿ 0.05). During remobilization, myofibrillar protein synthesis rates in the immobilized leg were greater with NPN$_1$ than those with MPC (1.53% ± 0.38% vs. 1.23% ± 0.36%/d, respectively; P = 0.027).nnCONCLUSION: NPN$_1$ supplementation does not differ from milk protein in modulating the loss of muscle size during short-term immobilization and the regain during remobilization in young men. NPN$_1$ supplementation does not differ from milk protein supplementation in modulating the myofibrillar protein synthesis rates during immobilization but further increases myofibrillar protein synthesis rates during remobilization.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36967049,

title = {Thigh Muscles Are More Susceptible to Age-Related Muscle Loss When Compared to Lower Leg and Pelvic Muscles},

author = {Cas J Fuchs and Remco Kuipers and Jan A Rombouts and Kim Brouwers and Vera B Schrauwen-Hinderling and Joachim E Wildberger and Lex B Verdijk and Luc J C Loon},

doi = {10.1016/j.exger.2023.112159},

issn = {1873-6815},

year  = {2023},

date = {2023-05-01},

journal = {Experimental gerontology},

volume = {175},

pages = {112159},

abstract = {BACKGROUND: A key hallmark of aging is the progressive loss of skeletal muscle mass. Due to limitations of the various methods typically applied to assess muscle mass, only limited information is available on age-related differences between various muscle groups. This study assessed differences in individual lower body muscle group volumes between healthy young and older males.nnMETHODS: Lower body muscle mass assessments were performed in 10 young (age: 27 ± 4 y) and 10 older (age: 71 ± 6 y) healthy, male adults using Dual-energy X-ray Absorptiometry (DXA), single slice (thigh) Computed Tomography (CT), as well as Magnetic Resonance Imaging (MRI). Muscle volumes of all individual muscle groups in the lower body were assessed by MRI.nnRESULTS: Leg lean mass, as assessed with DXA, was not significantly different between older (9.2 ± 1.0 kg) and young (10.5 ± 2.0 kg) men (P = 0.075). Thigh muscle cross-sectional area, as assessed with CT, was significantly lower (by 13 %) in the older (137 ± 17 cm) compared to young (157 ± 24 cm) participants (P = 0.044). MRI-derived lower body muscle volume was also significantly lower (by 20 %) in older (6.7 ± 0.9 L) compared to young (8.3 ± 1.3 L) men (P = 0.005). This was primarily attributed to substantial differences in thigh (24 %), rather than lower leg (12 %) and pelvis (15 %) muscle volume in the older vs the young. Thigh muscle volume averaged 3.4 ± 0.5 L in older and 4.5 ± 0.7 L in young men (P = 0.001). Of all thigh muscle groups, the quadriceps femoris showed the most profound difference (30 %) between young (2.3 ± 0.4 L) and older (1.6 ± 0.2 L) men (P ¡ 0.001).nnCONCLUSIONS: The most profound differences in lower body muscle volume between young and older men are observed in the thigh. Within the thigh muscle groups, the quadriceps femoris shows the largest difference in muscle volume between young and older men. Finally, DXA appears less sensitive when compared to CT and MRI to assess age-related differences in muscle mass.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36804484,

title = {Bone Turnover Following High-Impact Exercise Is Not Modulated by Collagen Supplementation in Young Men: A Randomized Cross-over Trial},

author = {Luuk Hilkens and Marleen Boerboom and Nick Schijndel and Judith Bons and Luc J C Loon and Jan-Willem Dijk},

doi = {10.1016/j.bone.2023.116705},

issn = {1873-2763},

year  = {2023},

date = {2023-05-01},

journal = {Bone},

volume = {170},

pages = {116705},

abstract = {INTRODUCTION: We assessed whether collagen supplementation augments the effects of high-impact exercise on bone turnover and whether a higher exercise frequency results in a greater benefit for bone metabolism.nnMETHODS: In this randomized, cross-over trial, 14 healthy males (age 24 ± 4 y, BMI 22.0 ± 2.1 kg/m) performed 5-min of high-impact exercise once (JUMP+PLA and JUMP+COL) or twice daily (JUMP2+COL2) during a 3-day intervention period, separated by a 10-day wash out period. One hour before every exercise bout participants ingested 20 g hydrolysed collagen (JUMP+COL and JUMP2+COL2) or a placebo control (JUMP+PLA). Blood markers of bone formation (P1NP) and resorption (CTXI) were assessed in the fasted state before the ingestion of the initial test drinks and 24, 48, and 72 h thereafter. In JUMP+PLA and JUMP+COL, additional blood samples were collected in the postprandial state at 1, 2, 3, 4, 5 and 13 h after ingestion of the test drink.nnRESULTS: In the postprandial state, serum P1NP concentrations decreased marginally from 99 ± 37 to 93 ± 33 ng/mL in JUMP+COL, and from 97 ± 32 to 92 ± 31 ng/mL in JUMP+PLA, with P1NP levels having returned to baseline levels after 13 h (time-effect},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36595659,

title = {Low Bone Mineral Density and Associated Risk Factors in Elite Cyclists at Different Stages of a Professional Cycling Career},

author = {Luuk Hilkens and Nick VAN Schijndel and Vera Weijer and Marleen Boerboom and Esther VAN DER Burg and Velibor Peters and Robert Kempers and Judith Bons and Luc J C VAN Loon and Jan-Willem VAN Dijk},

doi = {10.1249/MSS.0000000000003113},

issn = {1530-0315},

year  = {2023},

date = {2023-05-01},

journal = {Medicine and science in sports and exercise},

volume = {55},

number = {5},

pages = {957–965},

abstract = {PURPOSE: This study aimed to assess the prevalence of low bone mineral density (BMD) in male and female elite cyclists at different stages of a professional cycling career and to identify potential risk factors of low BMD.nnMETHODS: In this cross-sectional study, 93 male and female early career, advanced career, and postcareer elite cyclists completed dual-energy x-ray absorptiometry at the hip, femoral neck, lumbar spine, and total body; blood sampling; assessment of training history and injuries; and the bone-specific physical activity questionnaire. Backward stepwise multiple regression analyses were conducted to explore associations between BMD and its potential predictors in early and advanced career (i.e., active career) cyclists.nnRESULTS: With a mean Z -score of -0.3 ± 0.8, -1.5 ± 1.0, and -1.0 ± 0.9, low BMD ( Z -score ¡ -1) at the lumbar spine was present in 27%, 64%, and 50% of the early, advanced, and postcareer elite male cyclists, respectively. Lumbar spine Z -scores of -0.9 ± 1.0, -1.0 ± 1.0, and 0.2 ± 1.4 in early, advanced, and postcareer elite female cyclists, respectively, indicated low BMD in 45%, 45%, and 20% of these female subpopulations. Regression analyses identified body mass index, fracture incidence, bone-specific physical activity, and triiodothyronine as the main factors associated with BMD.nnCONCLUSIONS: Low BMD is highly prevalent in elite cyclists, especially in early career females and advanced career males and females. These low BMD values may not fully recover after the professional cycling career, given the substantial prevalence of low BMD in retired elite cyclists. Exploratory analyses indicated that low BMD is associated with low body mass index, fracture incidence, lack of bone-specific physical activity, and low energy availability in active career elite cyclists.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36534950,

title = {Resistance Exercise Training Increases Muscle Mass and Strength in Prostate Cancer Patients on Androgen Deprivation Therapy},

author = {Lisanne H P Houben and Maarten Overkamp and Puck VAN Kraaij and Jorn Trommelen and Joep G H VAN Roermund and Peter DE Vries and Kevin DE Laet and Saskia VAN DER Meer and Ulla R Mikkelsen and Lex B Verdijk and Luc J C VAN Loon and Sandra Beijer and Milou Beelen},

doi = {10.1249/MSS.0000000000003095},

issn = {1530-0315},

year  = {2023},

date = {2023-04-01},

journal = {Medicine and science in sports and exercise},

volume = {55},

number = {4},

pages = {614–624},

abstract = {PURPOSE: This study aimed to assess the effects of 20 wk resistance exercise training with or without protein supplementation on body composition, muscle mass, muscle strength, physical performance, and aerobic capacity in prostate cancer patients receiving androgen deprivation therapy (ADT).nnMETHODS: Sixty prostate cancer patients receiving ADT were randomly assigned to perform 20 wk of resistance exercise training with supplementation of 31 g whey protein (EX + PRO},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36621699,

title = {Muscle Fiber Type Grouping Does Not Change in Response to Prolonged Resistance Exercise Training in Healthy Older Men},

author = {Dominika Kraková and Andrew M Holwerda and Milan W Betz and Kaleen M Lavin and Marcas M Bamman and Luc J C Loon and Lex B Verdijk and Tim Snijders},

doi = {10.1016/j.exger.2023.112083},

issn = {1873-6815},

year  = {2023},

date = {2023-03-01},

journal = {Experimental gerontology},

volume = {173},

pages = {112083},

abstract = {BACKGROUND: Ageing of skeletal muscle is characterized in some by muscle fiber type grouping due to denervation-reinnervation cycles, but the severity of fiber type grouping varies widely across individuals of the same chronological age. It remains unknown whether fiber type grouping is associated with lower muscle mass and/or reduced physical function in elderly. Therefore, we assessed the relationship between fiber type grouping and indices of muscle mass and physical function in older adults. In addition, we assessed whether fiber type grouping is affected by prolonged resistance training in older adults.nnMETHODS: Twenty young (21 ± 2 y) and twenty older (70 ± 4 y) healthy men participated in the present study. Body composition (DXA-scan), quadriceps cross-sectional area (CT-scan) and muscle strength (1RM) were assessed at baseline (young and old) and following 12 weeks of resistance training (old only). Percutaneous skeletal muscle biopsies from the vastus lateralis were collected at baseline (young and old) and following exercise training (old only). Immunohistochemical analyses were performed to evaluate type I and type II muscle fiber distribution, size, myonuclear content and grouping.nnRESULTS: At baseline, type II fibers were significantly (P ¡ 0.05) smaller in older compared with young adults (5366 ± 1288 vs 6705 ± 1168 μm). Whereas no differences were observed in type I, type II fiber grouping was significantly (P ¡ 0.05) lower in older (18 ± 18 %) compared with young (32 ± 25 %) men. No significant correlations were observed between fiber type grouping and muscle mass or physical function. Prolonged resistance training in old men resulted in a significant increase (P ¡ 0.05) in type II fiber size (from 5366 ± 1288 to 6165 ± 1484 μm) with no significant changes in the proportion of type I muscle fibers found grouped.nnCONCLUSION: Muscle fiber type grouping is not associated with lower body strength or muscle mass in healthy, older men. In addition, twelve weeks of resistance exercise training results in type II muscle fiber specific hypertrophy but does not affect fiber type grouping.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36326863,

title = {Restricting Sugar or Carbohydrate Intake Does Not Impact Physical Activity Level or Energy Intake over 24 h despite Changes in Substrate Use: A Randomised Crossover Study in Healthy Men and Women},

author = {Aaron Hengist and Russell G Davies and Peter J Rogers and Jeff M Brunstrom and Luc J C Loon and Jean-Philippe Walhin and Dylan Thompson and Françoise Koumanov and James A Betts and Javier T Gonzalez},

doi = {10.1007/s00394-022-03048-x},

issn = {1436-6215},

year  = {2023},

date = {2023-03-01},

journal = {European journal of nutrition},

volume = {62},

number = {2},

pages = {921–940},

abstract = {PURPOSE: To determine the effects of dietary sugar or carbohydrate restriction on physical activity energy expenditure, energy intake, and physiological outcomes across 24 h.nnMETHODS: In a randomized, open-label crossover design, twenty-five healthy men (n = 10) and women (n = 15) consumed three diets over a 24-h period: moderate carbohydrate and sugar content (MODSUG = 50% carbohydrate [20% sugars], 15% protein, 35% fat); low sugar content (LOWSUG = 50% carbohydrate [¡ 5% sugars], 15% protein, 35% fat); and low carbohydrate content (LOWCHO = 8% carbohydrate [¡ 5% sugars], 15% protein, 77% fat). Postprandial metabolic responses to a prescribed breakfast (20% EI) were monitored under laboratory conditions before an ad libitum test lunch, with subsequent diet and physical activity monitoring under free-living conditions until blood sample collection the following morning.nnRESULTS: The MODSUG, LOWSUG and LOWCHO diets resulted in similar mean [95%CI] rates of both physical activity energy expenditure (771 [624, 919] vs. 677 [565, 789] vs. 802 [614, 991] kcal$cdot$d; p = 0.29] and energy intake (2071 [1794, 2347] vs. 2195 [1918, 2473] vs. 2194 [1890, 2498] kcal$cdot$d; P = 0.34), respectively. The LOWCHO condition elicited the lowest glycaemic and insulinaemic responses to breakfast (P ¡ 0.01) but the highest 24-h increase in LDL-cholesterol concentrations (P ¡ 0.001), with no differences between the MODSUG and LOWSUG treatments. Leptin concentrations decreased over 24-h of consuming LOWCHO relative to LOWSUG (p ¡ 0.01).nnCONCLUSION: When energy density is controlled for, restricting either sugar or total dietary carbohydrate does not modulate physical activity level or energy intake over a 24-h period ( 19-h free-living) despite substantial metabolic changes.nnCLINICAL TRIALS REGISTRATION ID: NCT03509610, https://clinicaltrials.gov/show/NCT03509610.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35988911,

title = {Intradialytic Protein Ingestion and Exercise Do Not Compromise Uremic Toxin Removal throughout Hemodialysis},

author = {Floris K Hendriks and Jeffrey H W Kuijpers and Janneau M X Kranenburg and Joan M G Senden and Frank M Sande and Jeroen P Kooman and Steven J R Meex and Luc J C Loon},

doi = {10.1053/j.jrn.2022.07.006},

issn = {1532-8503},

year  = {2023},

date = {2023-03-01},

journal = {Journal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation},

volume = {33},

number = {2},

pages = {376–385},

abstract = {OBJECTIVE: Dietary protein and physical activity interventions are increasingly implemented during hemodialysis to support muscle maintenance in patients with end-stage renal disease (ESRD). Although muscle maintenance is important, adequate removal of uremic toxins throughout hemodialysis is the primary concern for patients. It remains to be established whether intradialytic protein ingestion and/or exercise modulate uremic toxin removal during hemodialysis.nnMETHODS: We recruited 10 patients with ESRD (age: 65 ± 16 y, BMI: 24.2 ± 4.8 kg/m) on chronic hemodialysis treatment to participate in this randomized cross-over trial. During hemodialysis, patients were assigned to ingest 40 g protein or a nonprotein placebo both at rest (protein [PRO] and placebo [PLA], respectively) and following 30 min of exercise (PRO + exercise [EX] and PLA + EX, respectively). Blood and spent dialysate samples were collected throughout hemodialysis to assess reduction ratios and removal of urea, creatinine, phosphate, cystatin C, and indoxyl sulfate.nnRESULTS: The reduction ratios of urea and indoxyl sulfate were higher during PLA (76 ± 6% and 46 ± 9%, respectively) and PLA + EX interventions (77 ± 5% and 45 ± 10%, respectively) when compared to PRO (72 ± 4% and 40 ± 8%, respectively) and PRO + EX interventions (73 ± 4% and 43 ± 7%, respectively; protein effect: P = .001 and P = .023, respectively; exercise effect: P = .25 and P = .52, respectively). Nonetheless, protein ingestion resulted in greater urea removal (P = .046) during hemodialysis. Reduction ratios and removal of creatinine, phosphate, and cystatin C during hemodialysis did not differ following intradialytic protein ingestion or exercise (protein effect: P ¿ .05; exercise effect: P¿.05). Urea, creatinine, and phosphate removal were greater throughout the period with intradialytic exercise during PLA + EX and PRO + EX interventions when compared to the same period during PLA and PRO interventions (exercise effect: P = .034},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36546330,

title = {Eight-Hour Time-Restricted Eating Does Not Lower Daily Myofibrillar Protein Synthesis Rates: A Randomized Control Trial},

author = {Evelyn B Parr and Imre W K Kouw and Michael J Wheeler and Bridget E Radford and Rebecca C Hall and Joan M Senden and Joy P B Goessens and Luc J C Loon and John A Hawley},

doi = {10.1002/oby.23637},

issn = {1930-739X},

year  = {2023},

date = {2023-02-01},

journal = {Obesity (Silver Spring, Md.)},

volume = {31 Suppl 1},

number = {Suppl 1},

pages = {116–126},

abstract = {OBJECTIVE: This study aimed to assess the impact of time-restricted eating (TRE) on integrated skeletal muscle myofibrillar protein synthesis (MyoPS) rates in males with overweight/obesity.nnMETHODS: A total of 18 healthy males (age 46 ± 5 years; BMI: 30 ± 2 kg/m ) completed this exploratory, parallel, randomized dietary intervention after a 3-day lead-in diet. Participants then consumed an isoenergetic diet (protein: 1.0 g/kg body mass per day) following either TRE (10:00 a.m. to 6:00 p.m.) or an extended eating control (CON; 8:00 a.m. to 8:00 p.m.) protocol for 10 days. Integrated MyoPS rates were measured using deuterated water administration with repeated saliva, blood, and muscle sampling. Secondary measures included continuous glucose monitoring and body composition (dual-energy x-ray absorptiometry).nnRESULTS: There were no differences in daily integrated MyoPS rates (TRE: 1.28% ± 0.18% per day, CON: 1.26% ± 0.22% per day; p = 0.82) between groups. From continuous glucose monitoring, 24-hour total area under the curve was reduced following TRE (-578 ± 271 vs. CON: 12 ± 272 mmol/L × 24 hours; p = 0.001). Total body mass declined (TRE: -1.6 ± 0.9 and CON: -1.1 ± 0.7 kg; p ¡ 0.001) with no differences between groups (p = 0.22). Lean mass loss was greater following TRE compared with CON (-1.0 ± 0.7 vs. -0.2 ± 0.5 kg, respectively; p = 0.01).nnCONCLUSION: Consuming food within an 8-hour time-restricted period does not lower daily MyoPS rates when compared with an isoenergetic diet consumed over 12 hours. Future research should investigate whether these results translate to free-living TRE.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37154183,

title = {Energy Expenditure, Body Composition, and Skeletal Muscle Oxidative Capacity in Patients with Myotonic Dystrophy Type 1},

author = {Isis B T Joosten and Cas J Fuchs and Milou Beelen and Guy Plasqui and Luc J C Loon and Catharina G Faber},

doi = {10.3233/JND-230036},

issn = {2214-3602},

year  = {2023},

date = {2023-01-01},

journal = {Journal of neuromuscular diseases},

volume = {10},

number = {4},

pages = {701–712},

abstract = {BACKGROUND: Myotonic dystrophy type 1 (DM1) patients are at risk for metabolic abnormalities and commonly experience overweight and obesity. Possibly, weight issues result from lowered resting energy expenditure (EE) and impaired muscle oxidative metabolism.nnOBJECTIVES: This study aims to assess EE, body composition, and muscle oxidative capacity in patients with DM1 compared to age-, sex- and BMI-matched controls.nnMETHODS: A prospective case control study was conducted including 15 DM1 patients and 15 matched controls. Participants underwent state-of-the-art methodologies including 24 h whole room calorimetry, doubly labeled water and accelerometer analysis under 15-days of free-living conditions, muscle biopsy, full body magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DEXA), computed tomography (CT) upper leg, and cardiopulmonary exercise testing.nnRESULTS: Fat ratio determined by full body MRI was significantly higher in DM1 patients (56 [49-62] %) compared to healthy controls (44 [37-52] % ; p = 0.027). Resting EE did not differ between groups (1948 [1742-2146] vs (2001 [1853-2425¿] kcal/24 h, respectively; p = 0.466). In contrast, total EE was 23% lower in DM1 patients (2162 [1794-2494] vs 2814 [2424-3310] kcal/24 h; p = 0.027). Also, DM1 patients had 63% less steps (3090 [2263-5063] vs 8283 [6855-11485] steps/24 h; p = 0.003) and a significantly lower VO2 peak (22 [17-24] vs 33 [26-39] mL/min/kg; p = 0.003) compared to the healthy controls. Muscle biopsy citrate synthase activity did not differ between groups (15.4 [13.3-20.0] vs 20.1 [16.6-25.8] μM/g/min, respectively; p = 0.449).nnCONCLUSIONS: Resting EE does not differ between DM1 patients and healthy, matched controls when assessed under standardized circumstances. However, under free living conditions, total EE is substantially reduced in DM1 patients due to a lower physical activity level. The sedentary lifestyle of DM1 patients seems responsible for the undesirable changes in body composition and aerobic capacity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36913480,

title = {Acute Quark Ingestion Increases Muscle Protein Synthesis Rates at Rest with a Further Increase after Exercise in Young and Older Adult Males in a Parallel-Group Intervention Trial},

author = {Wesley Jh Hermans and Cas J Fuchs and Jean Nyakayiru and Floris K Hendriks and Lisanne Hp Houben and Joan M Senden and Luc Jc Loon and Lex B Verdijk},

doi = {10.1016/j.tjnut.2022.10.003},

issn = {1541-6100},

year  = {2023},

date = {2023-01-01},

journal = {The Journal of nutrition},

volume = {153},

number = {1},

pages = {66–75},

abstract = {BACKGROUND: Ingestion of protein concentrates or isolates increases muscle protein synthesis rates in young and older adults. There is far less information available on the anabolic response following the ingestion of dairy wholefoods, which are commonly consumed in a normal diet.nnOBJECTIVES: This study investigates whether ingestion of 30 g protein provided as quark increases muscle protein synthesis rates at rest and whether muscle protein synthesis rates are further increased after resistance exercise in young and older adult males.nnMETHODS: In this parallel-group intervention trial, 14 young (18-35 y) and 15 older (65-85 y) adult males ingested 30 g protein provided as quark after a single-legged bout of resistance exercise on leg press and leg extension machines. Primed, continuous intravenous L-[ring-C]-phenylalanine infusions were combined with the collection of blood and muscle tissue samples to assess postabsorptive and 4-h postprandial muscle protein synthesis rates at rest and during recovery from exercise. Data represent means ± SDs; η was used to measure the effect size.nnRESULTS: Plasma total amino acid and leucine concentrations increased after quark ingestion in both groups (both time: P ¡ 0.001; η ¿ 0.8), with no differences between groups (time × group: P = 0.127 and P = 0.172, respectively; η¡0.1). Muscle protein synthesis rates increased following quark ingestion at rest in both young (from 0.030 ± 0.011 to 0.051 ± 0.011 %$cdot$h) and older adult males (from 0.036 ± 0.011 to 0.062 ± 0.013 %$cdot$h), with a further increase in the exercised leg (to 0.071 ± 0.023 %$cdot$h and to 0.078 ± 0.019 %$cdot$h, respectively; condition: P ¡ 0.001; η = 0.716), with no differences between groups (condition × group: P = 0.747; η = 0.011).nnCONCLUSIONS: Quark ingestion increases muscle protein synthesis rates at rest with a further increase following exercise in both young and older adult males. The postprandial muscle protein synthetic response following quark ingestion does not differ between healthy young and older adult males when an ample amount of protein is ingested. This trial was registered at the Dutch Trial register, which is accessible via trialsearch.who.int www.trialregister.nl as NL8403.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36703515,

title = {Onset of Androgen Deprivation Therapy Leads to Rapid Deterioration of Body Composition, Physical Performance, Cardiometabolic Health and Quality-of-Life in Prostate Cancer Patients},

author = {Maarten Overkamp and Lisanne H P Houben and Saskia Meer and Joep G H Roermund and Ronald Bos and Arjan P J Kokshoorn and Mads S Larsen and Luc J C Loon and Milou Beelen and Sandra Beijer},

doi = {10.1080/21681805.2023.2168050},

issn = {2168-1813},

year  = {2023},

date = {2023-01-01},

journal = {Scandinavian journal of urology},

volume = {57},

number = {1-6},

pages = {60–66},

abstract = {OBJECTIVES: To assess the adverse impact of the first 5 months of androgen deprivation therapy on body composition, physical performance, cardiometabolic health and health-related quality-of-life in prostate cancer patients.nnMATERIALS AND METHODS: Thirty-four prostate cancer patients (70 ± 7 years) were assessed shortly after initiation of androgen deprivation therapy and again 5 months thereafter. Measurements consisted of whole-body dual-energy x-ray absorptiometry (body composition), computed tomography scanning of the upper leg (muscle mass), one-repetition maximum leg press (muscle strength), cardiopulmonary exercise testing (aerobic capacity), blood draws (metabolic parameters), accelerometry (habitual physical activity) and questionnaires (health-related quality-of-life). Data were analyzed with Student's paired -tests.nnRESULTS: Over time, whole-body fat mass (from 26.2 ± 7.7 to 28.4 ± 8.3 kg, ¡ 0.001) and fasting insulin (from 9.5 ± 5.8 to 11.3 ± 6.9 mU/L, ¡ 0.001) increased. Declines were observed for quadriceps cross-sectional area (from 66.3 ± 9.1 to 65.0 ± 8.5 cm, ¡ 0.01), one-repetition maximum leg press (from 107 ± 27 to 100 ± 27 kg, ¡ 0.01), peak oxygen uptake (from 23.2 ± 3.7 to 20.3 ± 3.4 mL/min/kg body weight, ¡ 0.001), step count (from 7,048 ± 2,277 to 5,842 ± 1,749 steps/day, ¡ 0.01) and health-related quality-of-life (from 84.6 ± 13.5 to 77.0 ± 14.6, ¡ 0.001).nnCONCLUSIONS: Androgen deprivation therapy induces adverse changes in body composition, muscle strength, cardiometabolic health and health-related quality-of-life already within 5 months after the start of treatment, possibly largely contributed by diminished habitual physical activity. Prostate cancer patients should, therefore, be stimulated to increase their habitual physical activity immediately after initiation of androgen deprivation therapy, to limit adverse side-effects and to improve health-related quality-of-life.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hilkens2023,

title = {Jumping Exercise Combined With Collagen Supplementation Preserves Bone Mineral Density in Elite Cyclists},

author = {Luuk Hilkens and Nick Van Schijndel and Vera C. R. Weijer and Lieselot Decroix and Judith Bons and Luc J. C. Van Loon and Jan-Willem Van Dijk},

url = {https://journals.humankinetics.com/view/journals/ijsnem/aop/article-10.1123-ijsnem.2023-0080/article-10.1123-ijsnem.2023-0080.xml},

doi = {10.1123/ijsnem.2023-0080},

issn = {1526-484X, 1543-2742},

year  = {2023},

date = {2023-01-01},

urldate = {2023-11-02},

journal = {International Journal of Sport Nutrition and Exercise Metabolism},

pages = {1–10},

abstract = {This study assessed the effect of combined jump training and collagen supplementation on bone mineral density (BMD) in elite road-race cyclists. In this open-label, randomized study with two parallel groups, 36 young (21 ± 3 years) male (n = 8) and female (n = 28) elite road-race cyclists were allocated to either an intervention (INT: n = 18) or a no-treatment control (CON: n = 18) group. The 18-week intervention period, conducted during the off-season, comprised five 5-min bouts of jumping exercise per week, with each bout preceded by the ingestion of 15 g hydrolyzed collagen. Before and after the intervention, BMD of various skeletal sites and trabecular bone score of the lumbar spine were assessed by dual-energy X-ray absorptiometry, along with serum bone turnover markers procollagen Type I N propeptide and carboxy-terminal cross-linking telopeptide of Type I collagen. BMD of the femoral neck decreased in CON (from 0.789 ± 0.104 to 0.774 ± 0.095 g/cm2), while being preserved in INT (from 0.803 ± 0.058 to 0.809 ± 0.066 g/cm2; Time × Treatment, p $<$ .01). No differences between treatments were observed for changes in BMD at the total hip, lumbar spine, and whole body (Time × Treatment, p $>$ .05 for all). Trabecular bone score increased from 1.38 ± 0.08 to 1.40 ± 0.09 in CON and from 1.46 ± 0.08 to 1.47 ± 0.08 in INT, respectively (time effect: p $<$ .01), with no differences between treatments (Time × Treatment: p = .33). Serum procollagen Type I N propeptide concentrations decreased to a similar extent in CON (83.6 ± 24.8 to 71.4 ± 23.1 ng/ml) and INT (82.8 ± 30.7 to 66.3 ± 30.6; time effect, p $<$ .001; Time × Treatment},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36374263,

title = {Twist2-Expressing Cells Reside in Human Skeletal Muscle and Are Responsive to Aging and Resistance Exercise Training},

author = {Nick Gaulton and Griffen Wakelin and Laura V Young and Scott Wotherspoon and Michael Kamal and Gianni Parise and Joshua P Nederveen and Andy Holwerda and Lex B Verdijk and Luc J C Loon and Tim Snijders and Adam P Johnston},

doi = {10.1096/fj.202201349RR},

issn = {1530-6860},

year  = {2022},

date = {2022-12-01},

journal = {The FASEB journal : official publication of the Federation of American Societies for Experimental Biology},

volume = {36},

number = {12},

pages = {e22642},

abstract = {Skeletal muscle is maintained and repaired by sub-laminar, Pax7-expressing satellite cells. However, recent mouse investigations have described a second myogenic progenitor population that resides within the myofiber interstitium and expresses the transcription factor Twist2. Twist2-expressing cells exclusively repair and maintain type IIx/b muscle fibers. Currently, it is unknown if Twist2-expressing cells are present in human skeletal muscle and if they function as myogenic progenitors. Here, we perform a combination of single-cell RNA sequencing analysis and immunofluorescence staining to demonstrate the identity and localization of Twist2-expressing cells in human skeletal muscle. Twist2-expressing cells were identified to be anatomically and transcriptionally comparable to fibro-adipogenic progenitors (FAPs) and lack expression of typical satellite cell markers such as Pax7. Comparative analysis revealed that human and mouse Twist2-expressing cells were highly transcriptionally analogous and resided within the same anatomical structures in vivo. Examination of young and aged skeletal muscle biopsy samples revealed that Twist2-positive cells are more prevalent in aged muscle and increase following 12-weeks of resistance exercise training (RET) in humans. However, the quantity of Twist2-positive cells was not correlated with indices of muscle mass or muscle fiber cross-sectional area (CSA) in young or older muscle, and their abundance was surprisingly, negatively correlated with CSA and myonuclear domain size following RET. Taken together, we have identified cells expressing Twist2 in human skeletal muscle which are responsive to aging and exercise. Further examination of their myogenic potential is warranted.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36774104,

title = {Raw Eggs to Support Postexercise Recovery in Healthy Young Men: Did Rocky Get It Right or Wrong?},

author = {Cas J Fuchs and Wesley Jh Hermans and Joey Sj Smeets and Joan M Senden and Janneau Kranenburg and Stefan Hm Gorissen and Nicholas A Burd and Lex B Verdijk and Luc Jc Loon},

doi = {10.1093/jn/nxac174},

issn = {1541-6100},

year  = {2022},

date = {2022-11-01},

journal = {The Journal of nutrition},

volume = {152},

number = {11},

pages = {2376–2386},

abstract = {BACKGROUND: Egg protein is ingested during recovery from exercise to facilitate the postexercise increase in muscle protein synthesis rates and, as such, to support the skeletal muscle adaptive response to exercise training. The impact of cooking egg protein on postexercise muscle protein synthesis is unknown.nnOBJECTIVES: We sought to compare the impact of ingesting unboiled (raw) compared with boiled eggs during postexercise recovery on postprandial myofibrillar protein synthesis rates.nnMETHODS: In a parallel design, 45 healthy, resistance-trained young men (age: 24 y; 95% CI: 23, 25 y) were randomly assigned to ingest 5 raw eggs ($sim$30 g protein), 5 boiled eggs ($sim$30 g protein), or a control breakfast ($sim$5 g protein) during recovery from a single session of whole-body resistance-type exercise. Primed continuous l-[ring-C]-phenylalanine infusions were applied, with frequent blood sampling. Muscle biopsies were collected immediately after cessation of resistance exercise and at 2 and 5 h into the postexercise recovery period. Primary (myofibrillar protein synthesis rates) and secondary (plasma amino acid concentrations) outcomes were analyzed using repeated-measures (time × group) ANOVA.nnRESULTS: Ingestion of eggs significantly increased plasma essential amino acid (EAA) concentrations, with 20% higher peak concentrations following ingestion of boiled compared with raw eggs (time × group: P ¡ 0.001). Myofibrillar protein synthesis rates were significantly increased during the postexercise period when compared with basal, postabsorptive values in all groups (2-4-fold increase: P ¡ 0.001). Postprandial myofibrillar protein synthesis rates were 20% higher after ingesting raw eggs [0.067%/h; 95% CI: 0.056, 0.077%/h; effect size (Cohen d): 0.63], and 18% higher after ingesting boiled eggs (0.065%/h; 95% CI: 0.058, 0.073%/h; effect size: 0.69) when compared with the control breakfast (0.056%/h; 95% CI: 0.048, 0.063%/h), with no significant differences between groups (time × group: P = 0.077).nnCONCLUSIONS: The ingestion of raw, as opposed to boiled, eggs attenuates the postprandial rise in circulating EAA concentrations. However, postexercise muscle protein synthesis rates do not differ after ingestion of 5 raw compared with 5 boiled eggs in healthy young men. This trial was registered at the Nederlands Trial Register as NL6506 (www.trialregister.nl).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{philippej.m.pinckaers2022,

title = {The Muscle Protein Synthetic Response to the Ingestion of a Plant-Derived Protein Blend Does Not Differ from an Equivalent Amount of Milk Protein in Healthy, Young Males},

author = {Philippe J. M. Pinckaers and Imre W. K. Kouw and Stefan H. M. Gorissen and Stefan H. M. Gorissen and Lisanne H P Houben and Joan M. Senden and Joan M. G. Senden and Will K. W. H. Wodzig and Lisette C. P. G. M. Groot and Lex B. Verdijk and Tim Snijders and Luc J. C. Loon},

doi = {10.1093/jn/nxac222},

year  = {2022},

date = {2022-09-01},

urldate = {2022-09-01},

journal = {Journal of Nutrition},

volume = {152},

issue = {12},

pages = {2734-2743},

abstract = {Abstract Background Plant-derived proteins are considered to have lesser anabolic properties when compared with animal-derived proteins. The attenuated rise in muscle protein synthesis rates following ingestion of plant compared with animal-derived protein has been, at least partly, attributed to deficiencies in specific amino acids such as leucine, lysine, and/or methionine. Combining different plant-derived proteins may provide plant-derived protein blends with a more balanced amino acid profile. Objective This study aimed to compare post-prandial muscle protein synthesis rates following the ingestion of 30 g milk protein with a 30 g blend combining wheat, corn, and pea protein in healthy, young males. Design In a randomized, double blind, parallel-group design, 24 young males (24 ± 4 y) received a primed continuous L-[ring-13C6]-phenylalanine infusion after which they ingested 30 g milk protein (MILK) or a 30 g plant-derived protein blend combining 15 g wheat, 7.5 g corn, and 7.5 g pea protein (PLANT-BLEND). Blood and muscle biopsies were collected frequently for 5 h to assess post-prandial plasma amino acid profiles (secondary outcome) and subsequent muscle protein synthesis rates (primary outcome). Data were analyzed by two way-repeated measures ANOVA and two-samples t-tests. Results MILK increased plasma essential amino acid concentrations more than PLANT-BLEND over the 5 h postprandial period (incremental area under curve 151±31 vs 79 ± 12 mmol$bullet$300 min$bullet$L-1 respectively; P < 0.001). Ingestion of both MILK and PLANT-BLEND increased myofibrillar protein synthesis rates (P < 0.001), with no significant differences between treatments (0.053 ± 0.013 and 0.064 ± 0.016%$bullet$h-1, respectively; P = 0.08) Conclusion Ingestion of 30 g of a plant-derived protein blend combining wheat, corn, and pea-derived protein increases muscle protein synthesis rates in healthy, young males. The muscle protein synthetic response to the ingestion of 30 g of this plant-derived protein blend does not differ from the ingestion of an equivalent amount of a high quality animal-derived protein. Clinical Trial Registry number: Nederlands Trial Register: NTR6548 https://www.trialregister.nl/},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35686720,

title = {Nutritional Strategies to Attenuate Postprandial Glycemic Response},

author = {Kenneth Pasmans and Ruth C R Meex and Luc J C Loon and Ellen E Blaak},

doi = {10.1111/obr.13486},

issn = {1467-789X},

year  = {2022},

date = {2022-09-01},

journal = {Obesity reviews : an official journal of the International Association for the Study of Obesity},

volume = {23},

number = {9},

pages = {e13486},

abstract = {Maintaining good glycemic control to prevent complications is crucial in people with type 2 diabetes and in people with prediabetes and in the general population. Different strategies to improve glycemic control involve the prescription of blood glucose-lowering drugs and the modulation of physical activity and diet. Interestingly, lifestyle intervention may be more effective in lowering hyperglycemia than pharmaceutical intervention. Regulation of postprandial glycemia is complex, but specific nutritional strategies can be applied to attenuate postprandial hyperglycemia. These strategies include reducing total carbohydrate intake, consuming carbohydrates with a lower glycemic index, the addition of or substitution by sweeteners and fibers, using food compounds which delay or inhibit gastric emptying or carbohydrate digestion, and using food compounds which inhibit intestinal glucose absorption. Nevertheless, it must be noted that every individual may respond differently to certain nutritional interventions. Therefore, a personalized approach is of importance to choose the optimal nutritional strategy to improve postprandial glycemia for each individual, but this requires a better understanding of the mechanisms explaining the differential responses between individuals.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35584344,

title = {Muscle Protein Synthesis after Protein Administration in Critical Illness},

author = {Lee-Anne S Chapple and Imre W K Kouw and Matthew J Summers and Luke M Weinel and Samuel Gluck and Eamon Raith and Peter Slobodian and Stijn Soenen and Adam M Deane and Luc J C Loon and Marianne J Chapman},

doi = {10.1164/rccm.202112-2780OC},

issn = {1535-4970},

year  = {2022},

date = {2022-09-01},

journal = {American journal of respiratory and critical care medicine},

volume = {206},

number = {6},

pages = {740–749},

abstract = {Dietary protein may attenuate the muscle atrophy experienced by patients in the ICU, yet protein handling is poorly understood. To quantify protein digestion and amino acid absorption and fasting and postprandial myofibrillar protein synthesis during critical illness. Fifteen mechanically ventilated adults (12 male; aged 50 ± 17 yr; body mass index, 27 ± 5 kg$cdot$m) and 10 healthy control subjects (6 male; 54 ± 23 yr; body mass index, 27 ± 4 kg$cdot$m) received a primed intravenous L-[ring-H]-phenylalanine, L-[3,5-H]-tyrosine, and L-[1-C]-leucine infusion over 9.5 hours and a duodenal bolus of intrinsically labeled (L-[1-C]-phenylalanine and L-[1-C]-leucine) intact milk protein (20 g protein) over 60 minutes. Arterial blood and muscle samples were taken at baseline (fasting) and for 6 hours following duodenal protein administration. Data are mean ± SD, analyzed with two-way repeated measures ANOVA and independent samples test. Fasting myofibrillar protein synthesis rates did not differ between ICU patients and healthy control subjects (0.023 ± 0.013% h vs. 0.034 ± 0.016% h; = 0.077). After protein administration, plasma amino acid availability did not differ between groups (ICU patients, 54.2 ± 9.1%, vs. healthy control subjects, 61.8 ± 13.1%; = 0.12), and myofibrillar protein synthesis rates increased in both groups (0.028 ± 0.010% h vs. 0.043 ± 0.018% h; main time effect = 0.046; -interaction = 0.584) with lower rates in ICU patients than in healthy control subjects (main group effect = 0.001). Incorporation of protein-derived phenylalanine into myofibrillar protein was $sim$60% lower in ICU patients (0.007 ± 0.007 mol percent excess vs. 0.017 ± 0.009 mol percent excess; = 0.007). The capacity for critically ill patients to use ingested protein for muscle protein synthesis is markedly blunted despite relatively normal protein digestion and amino acid absorption.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35438672,

title = {Potato Protein Ingestion Increases Muscle Protein Synthesis Rates at Rest and during Recovery from Exercise in Humans},

author = {Philippe J M Pinckaers and Floris K Hendriks and Wesley J H Hermans and Joy P B Goessens and Joan M Senden and Janneau M X VAN Kranenburg and Will K H W Wodzig and Tim Snijders and Luc J C VAN Loon},

doi = {10.1249/MSS.0000000000002937},

issn = {1530-0315},

year  = {2022},

date = {2022-09-01},

journal = {Medicine and science in sports and exercise},

volume = {54},

number = {9},

pages = {1572–1581},

abstract = {INTRODUCTION: Plant-derived proteins have received considerable attention as an alternative to animal-based proteins and are now frequently used in both plant-based diets and sports nutrition products. However, little information is available on the anabolic properties of potato-derived protein. This study compares muscle protein synthesis rates after the ingestion of 30 g potato protein versus 30 g milk protein at rest and during recovery from a single bout of resistance exercise in healthy, young males.nnMETHODS: In a randomized, double-blind, parallel-group design, 24 healthy young males (24 ± 4 yr) received primed continuous l -[ ring - 13 C 6 ]-phenylalanine infusions while ingesting 30 g potato-derived protein or 30 g milk protein after a single bout of unilateral resistance exercise. Blood and muscle biopsies were collected for 5 h after protein ingestion to assess postprandial plasma amino acid profiles and mixed muscle protein synthesis rates at rest and during recovery from exercise.nnRESULTS: Ingestion of both potato and milk protein increased mixed muscle protein synthesis rates when compared with basal postabsorptive values (from 0.020% ± 0.011% to 0.053% ± 0.017%$cdot$h -1 and from 0.021% ± 0.014% to 0.050% ± 0.012%$cdot$h -1 , respectively; P ¡ 0.001), with no differences between treatments ( P = 0.54). In the exercised leg, mixed muscle protein synthesis rates increased to 0.069% ± 0.019% and 0.064% ± 0.015%$cdot$h -1 after ingesting potato and milk protein, respectively ( P ¡ 0.001), with no differences between treatments ( P = 0.52). The muscle protein synthetic response was greater in the exercised compared with the resting leg ( P ¡ 0.05).nnCONCLUSIONS: Ingestion of 30 g potato protein concentrate increases muscle protein synthesis rates at rest and during recovery from exercise in healthy, young males. Muscle protein synthesis rates after the ingestion of 30 g potato protein do not differ from rates observed after ingesting an equivalent amount of milk protein.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35732003,

title = {Dietary Nitrate Increases Submaximal SERCA Activity and ADP Transfer to Mitochondria in Slow-Twitch Muscle of Female Mice},

author = {Heather L Petrick and Stuart Brownell and Bayley Vachon and Henver S Brunetta and Rachel M Handy and Luc J C Loon and Coral L Murrant and Graham P Holloway},

doi = {10.1152/ajpendo.00371.2021},

issn = {1522-1555},

year  = {2022},

date = {2022-08-01},

journal = {American journal of physiology. Endocrinology and metabolism},

volume = {323},

number = {2},

pages = {E171–E184},

abstract = {Rapid oscillations in cytosolic calcium (Ca) coordinate muscle contraction, relaxation, and physical movement. Intriguingly, dietary nitrate decreases ATP cost of contraction, increases force production, and increases cytosolic Ca, which would seemingly necessitate a greater demand for sarcoplasmic reticulum Ca ATPase (SERCA) to sequester Ca within the sarcoplasmic reticulum (SR) during relaxation. As SERCA is highly regulated, we aimed to determine the effect of 7-day nitrate supplementation (1 mM via drinking water) on SERCA enzymatic properties and the functional interaction between SERCA and mitochondrial oxidative phosphorylation. In soleus, we report that dietary nitrate increased force production across all stimulation frequencies tested, and throughout a 25 min fatigue protocol. Mice supplemented with nitrate also displayed an $sim$25% increase in submaximal SERCA activity and SERCA efficiency ( = 0.053) in the soleus. To examine a possible link between ATP consumption and production, we established a methodology coupling SERCA and mitochondria in permeabilized muscle fibers. The premise of this experiment is that the addition of Ca in the presence of ATP generates ADP from SERCA to support mitochondrial respiration. Similar to submaximal SERCA activity, mitochondrial respiration supported by SERCA-derived ADP was increased by $sim$20% following nitrate in red gastrocnemius. This effect was fully attenuated by the SERCA inhibitor cyclopiazonic acid and was not attributed to differences in mitochondrial oxidative capacity, ADP sensitivity, protein content, or reactive oxygen species emission. Overall, these findings suggest that improvements in submaximal SERCA kinetics may contribute to the effects of nitrate on force production during fatigue. We show that nitrate supplementation increased force production during fatigue and increased submaximal SERCA activity. This was also evident regarding the high-energy phosphate transfer from SERCA to mitochondria, as nitrate increased mitochondrial respiration supported by SERCA-derived ADP. Surprisingly, these observations were only apparent in muscle primarily expressing type I (soleus) but not type II fibers (EDL). These findings suggest that alterations in SERCA properties are a possible mechanism in which nitrate increases force during fatiguing contractions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Stevens2022b,

title = {Skeletal Muscle Fibre Characteristics of the Lumbar Multifidus Muscle in Patients Undergoing Microdiscectomy for Unilateral Lumbar Disc Herniation},

author = {S. Stevens and A. Agten and T. Snijders and M. Plazier and S. Bamps and T. Assieker and M. W. Betz and A. Timmermans and L. J. C. Loon and F. Vandenabeele},

doi = {10.32098/mltj.03.2022.19},

issn = {2240-4554},

year  = {2022},

date = {2022-07-00},

journal = {Muscle Ligaments and Tendons J},

volume = {12},

number = {03},

publisher = {Edra SpA},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Stevens2022,

title = {Skeletal Muscles of Patients Infected with SARS-CoV-2 Develop Severe Myofiber Damage upon One Week of Admission on the Intensive Care Unit},

author = {Sjoerd Stevens and Paul Hendrickx and Tim Snijders and Ivo Lambrichts and Björn Stessel and Jasperina Dubois and Luc J. C. Loon and Frank Vandenabeele and Anouk Agten},

doi = {10.3390/app12147310},

issn = {2076-3417},

year  = {2022},

date = {2022-07-00},

journal = {Applied Sciences},

volume = {12},

number = {14},

publisher = {MDPI AG},

abstract = {¡jats:p¿Many critically ill patients infected with SARS-CoV-2 have been submitted to an intensive care unit (ICU). Patients with a SARS-CoV-2 infection that survive critical illness are confronted with months of physical impairments. To maximize recovery, it is important to understand the musculoskeletal involvement in critically ill patients infected with SARS-CoV-2. The aim of the present study was to assess the myocellular changes in SARS-CoV-2 patients that occur throughout the first week of ICU admission. In n = 22 critically ill patients infected with SARS-CoV-2, a biopsy sample from the vastus lateralis muscle was obtained at day 1–3 and day 5–8 following ICU admission. Fluorescence microscopy was used to assess type I and type II muscle fiber size and distribution, myonuclear content, and muscle tissue capillarization. Transmission electron microscopy was used to support quantitative data at an ultrastructural level. Changes in type I and type II muscle fiber size showed large inter-individual variation. The average change in type I fiber size was +309 ± 1834 µm2, ranging from -2129 µm2 (-31%) to +3375 µm2 (+73%). The average change in type II fiber size was -224 ± 1256 µm2, ranging from -1410 µm2 (-36%) to +2592 µm2 (+48%). Ultrastructural observations showed myofibrillar and hydropic degeneration, and fiber necrosis. This study shows that ICU patients admitted with SARS-CoV-2 suffer from substantial muscle fiber damage during ICU admission. These results are a call for action towards more specialized rehabilitation programs for patients admitted to the ICU with SARS-CoV-2 infection.¡/jats:p¿},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35108354,

title = {Perspective: Vegan Diets for Older Adults? A Perspective on the Potential Impact on Muscle Mass and Strength},

author = {Jacintha Domić and Pol Grootswagers and Luc J C Loon and Lisette C P G M Groot},

doi = {10.1093/advances/nmac009},

issn = {2156-5376},

year  = {2022},

date = {2022-06-01},

journal = {Advances in nutrition (Bethesda, Md.)},

volume = {13},

number = {3},

pages = {712–725},

abstract = {Consumers are increasingly encouraged to consume more plant-based foods and lower their consumption of foods from animal origin. Concurrently, older adults are recommended to consume an adequate amount of high-quality dietary protein for the prevention of age-related muscle loss. In the current Perspective article, we discuss why it may not be preferred to consume a vegan diet at an older age. Our perspective is based on the proposed lower bioavailability and functionality of proteins in a vegan diet due to the matrix of the whole-food protein sources, the lower essential amino acid (EAA) content, and specific EAA deficiencies in proteins derived from plant-based foods. We propose that a vegan diet increases the risk of an inadequate protein intake at an older age and that current strategies to improve the anabolic properties of plant-based foods are not feasible for many older adults. We provide recommendations for further research to substantiate the remaining knowledge gaps regarding the consequences of a vegan diet on skeletal muscle mass and strength at an older age.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35578224,

title = {"I Want to Get Myself as Fit as I Can and Not Die Just yet" - Perceptions of Exercise in People with Advanced Cancer and Cachexia: A Qualitative Study},

author = {Kelcey A Bland and Meinir Krishnasamy and Evelyn B Parr and Stella Mulder and Peter Martin and Luc J C Loon and Prue Cormie and Natasha Michael and Eva M Zopf},

doi = {10.1186/s12904-022-00948-x},

issn = {1472-684X},

year  = {2022},

date = {2022-05-01},

journal = {BMC palliative care},

volume = {21},

number = {1},

pages = {75},

abstract = {Cachexia is a prevalent muscle wasting syndrome among people with advanced cancer that profoundly impacts patient quality of life (QoL) and physical function. Exercise can improve QoL, physical function, and overall health in people with cancer and may be an important addition to treatment approaches for cancer cachexia. Greater understanding of patients' perception of exercise can help elucidate the feasibility of implementing exercise interventions for cancer cachexia and facilitate the design of patient-centered interventions. We aimed to describe the perception of exercise in patients with advanced cancer and cachexia, and capture exercise motivators, barriers, and preferences, to inform the feasibility of exercise interventions. Individual interviews (n = 20) with patients with locally advanced or metastatic cancer with cachexia were conducted and analyzed using reflexive thematic analysis. Main themes from interviews were: 1) Life is disrupted by cancer and cachexia; 2) Exercise offers hope; 3) Exercise barriers are multifaceted; and 4) Exercise access and support are important. Participants reported that their cancer and cachexia had intensely altered their lives, including ability to exercise. Exercise was perceived as important and participants described a hope for exercise to improve their health and wellbeing. Yet, several complex exercise barriers, such as burdensome cancer symptoms and the overwhelming impact of the COVID-19 pandemic, hindered exercise participation and prevented participants from fully realizing the perceived benefits of exercise. Factors believed to improve exercise engagement and overcome exercise barriers included increased exercise support (e.g., professional supervision) and accessibility (e.g., convenient locations). Patient-reported exercise barriers and preferences can inform the design of exercise interventions, particularly within future research studies aiming to establish exercise feasibility and efficacy in people with advanced cancer and cachexia.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35534615,

title = {Myofibrillar Protein Synthesis Rates Are Increased in Chronically Exercised Skeletal Muscle despite Decreased Anabolic Signaling},

author = {Henning T Langer and Daniel West and Joan Senden and Simone Spuler and Luc J C Loon and Keith Baar},

doi = {10.1038/s41598-022-11621-x},

issn = {2045-2322},

year  = {2022},

date = {2022-05-01},

journal = {Scientific reports},

volume = {12},

number = {1},

pages = {7553},

abstract = {The molecular responses to acute resistance exercise are well characterized. However, how cellular signals change over time to modulate chronic adaptations to more prolonged exercise training is less well understood. We investigated anabolic signaling and muscle protein synthesis rates at several time points after acute and chronic eccentric loading. Adult rat tibialis anterior muscle was stimulated for six sets of ten repetitions, and the muscle was collected at 0 h, 6 h, 18 h and 48 h. In the last group of animals, 48 h after the first exercise bout a second bout was conducted, and the muscle was collected 6 h later (54 h total). In a second experiment, rats were exposed to four exercise sessions over the course of 2 weeks. Anabolic signaling increased robustly 6 h after the first bout returning to baseline between 18 and 48 h. Interestingly, 6 h after the second bout mTORC1 activity was significantly lower than following the first bout. In the chronically exercised rats, we found baseline anabolic signaling was decreased, whereas myofibrillar protein synthesis (MPS) was substantially increased, 48 h after the last bout of exercise. The increase in MPS occurred in the absence of changes to muscle fiber size or mass. In conclusion, we find that anabolic signaling is already diminished after the second bout of acute resistance type exercise. Further, chronic exposure to resistance type exercise training results in decreased basal anabolic signaling but increased overall MPS rates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35118634,

title = {Exercise-Based Interventions to Counteract Skeletal Muscle Mass Loss in People with Cancer: Can We Overcome the Odds?},

author = {Kelcey A Bland and Imre W K Kouw and Luc J C Loon and Eva M Zopf and Ciaran M Fairman},

doi = {10.1007/s40279-021-01638-z},

issn = {1179-2035},

year  = {2022},

date = {2022-05-01},

journal = {Sports medicine (Auckland, N.Z.)},

volume = {52},

number = {5},

pages = {1009–1027},

abstract = {Addressing skeletal muscle mass loss is an important focus in oncology research to improve clinical outcomes, including cancer treatment tolerability and survival. Exercise is likely a necessary component of muscle-mass-preserving interventions for people with cancer. However, randomized controlled trials with exercise that include people with cancer with increased susceptibility to more rapid and severe muscle mass loss are limited. The aim of the current review is to highlight features of cancer-related skeletal muscle mass loss, discuss the impact in patients most at risk, and describe the possible role of exercise as a management strategy. We present current gaps within the exercise oncology literature and offer several recommendations for future studies to support research translation, including (1) utilizing accurate and reliable body composition techniques to assess changes in skeletal muscle mass, (2) incorporating comprehensive assessments of patient health status to allow personalized exercise prescription, (3) coupling exercise with robust nutritional recommendations to maximize the impact on skeletal muscle outcomes, and (4) considering key exercise intervention features that may improve exercise efficacy and adherence. Ultimately, the driving forces behind skeletal muscle mass loss are complex and may impede exercise tolerability and efficacy. Our recommendations are intended to foster the design of high-quality patient-centred research studies to determine whether exercise can counteract muscle mass loss in people with cancer and, as such, improve knowledge on this topic.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid34605901,

title = {The Impact of Collagen Protein Ingestion on Musculoskeletal Connective Tissue Remodeling: A Narrative Review},

author = {Andrew M Holwerda and Luc J C Loon},

doi = {10.1093/nutrit/nuab083},

issn = {1753-4887},

year  = {2022},

date = {2022-05-01},

journal = {Nutrition reviews},

volume = {80},

number = {6},

pages = {1497–1514},

abstract = {Collagen is the central structural component of extracellular connective tissue, which provides elastic qualities to tissues. For skeletal muscle, extracellular connective tissue transmits contractile force to the tendons and bones. Connective tissue proteins are in a constant state of remodeling and have been shown to express a high level of plasticity. Dietary-protein ingestion increases muscle protein synthesis rates. High-quality, rapidly digestible proteins are generally considered the preferred protein source to maximally stimulate myofibrillar (contractile) protein synthesis rates. In contrast, recent evidence demonstrates that protein ingestion does not increase muscle connective tissue protein synthesis. The absence of an increase in muscle connective tissue protein synthesis after protein ingestion may be explained by insufficient provision of glycine and/or proline. Dietary collagen contains large amounts of glycine and proline and, therefore, has been proposed to provide the precursors required to facilitate connective tissue protein synthesis. This literature review provides a comprehensive evaluation of the current knowledge on the proposed benefits of dietary collagen consumption to stimulate connective tissue remodeling to improve health and functional performance.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hermans2022,

title = {Cheese Ingestion Increases Muscle Protein Synthesis Rates Both at Rest and during Recovery from Exercise in Healthy, Young Males: A Randomized Parallel-Group Trial},

author = {Wesley J H Hermans and Cas J Fuchs and Floris K Hendriks and Lisanne H P Houben and Joan M Senden and Lex B Verdijk and Luc J C Loon},

doi = {10.1093/jn/nxac007},

issn = {1541-6100},

year  = {2022},

date = {2022-04-01},

journal = {The Journal of nutrition},

volume = {152},

number = {4},

pages = {1022–1030},

abstract = {BACKGROUND: Protein ingestion increases muscle protein synthesis rates. The food matrix in which protein is provided can strongly modulate the postprandial muscle protein synthetic response. So far, the muscle protein synthetic response to the ingestion of whole foods remains largely unexplored.nnOBJECTIVES: To compare the impact of ingesting 30 g protein provided as milk protein or cheese on postprandial plasma amino acid concentrations and muscle protein synthesis rates at rest and during recovery from exercise in vivo in young males.nnMETHODS: In this randomized, parallel-group intervention trial, 20 healthy males aged 18-35 y ingested 30 g protein provided as cheese or milk protein concentrate following a single-legged resistance-type exercise session consisting of 12 sets of leg press and leg extension exercises. Primed, continuous intravenous L-[ring-C]-phenylalanine infusions were combined with the collection of blood and muscle tissue samples to assess postabsorptive and 4-h postprandial muscle protein synthesis rates at rest and during recovery from exercise. Data were analyzed using repeated measures Time × Group (× Leg) ANOVA.nnRESULTS: Plasma total amino acid concentrations increased after protein ingestion (Time: P ¡ 0.001), with 38% higher peak concentrations following milk protein than cheese ingestion (Time × Group: P ¡ 0.001). Muscle protein synthesis rates increased following both cheese and milk protein ingestion from 0.037 ± 0.014 to 0.055 ± 0.018%$cdot$h and 0.034 ± 0.008 to 0.056 ± 0.010%$cdot$h at rest and even more following exercise from 0.031 ± 0.010 to 0.067 ± 0.013%$cdot$h and 0.030 ± 0.008 to 0.063 ± 0.010%$cdot$h, respectively (Time: all P ¡ 0.05; Time × Leg: P = 0.002), with no differences between cheese and milk protein ingestion (Time × Group: both P ¿ 0.05).nnCONCLUSION: Cheese ingestion increases muscle protein synthesis rates both at rest and during recovery from exercise. The postprandial muscle protein synthetic response to the ingestion of cheese or milk protein does not differ when 30 g protein is ingested at rest or during recovery from exercise in healthy, young males.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid35120409,

title = {Relative Validity and Reliability of Isometric Lower Extremity Strength Assessment in Older Adults by Using a Handheld Dynamometer},

author = {Pol Grootswagers and Anouk M M Vaes and Roland Hangelbroek and Michael Tieland and Luc J C Loon and Lisette C P G M Groot},

doi = {10.1177/19417381211063847},

issn = {1941-0921},

year  = {2022},

date = {2022-01-01},

journal = {Sports Health},

volume = {14},

number = {6},

pages = {899–905},

abstract = {BACKGROUND: Handheld dynamometry (HHD) is a practical alternative to traditional testing of lower extremity strength. However, its reliability and validity across different populations and settings are not clear.nnHYPOTHESIS: We hypothesize that HHD is a valid and reliable device to assess lower extremity strength in a population of older adults.nnSTUDY DESIGN: Cross-sectional/cohort.nnLEVEL OF EVIDENCE: Level 3.nnMETHODS: This study included 258 older adults ($geq$65 years). Isometric knee extension and flexion force were measured by 1 examiner, using an HHD (n = 222), including 3 repetitions to calculate within-day intrarater reliability. These measurements were repeated by the examiner in a subgroup (n = 23) to analyze intrarater reliability over a test-retest period of on average 8 weeks. In addition, HHD force measures were performed by a second examiner (n = 29) to analyze interrater reliability. In another subgroup (n = 77), isometric knee extension and flexion torque were measured by 1 examiner using both the HHD and Biodex System 4 to assess relative validity.nnRESULTS: HHD and Biodex measurements were highly correlated and showed excellent concurrent validity. HHD systematically overestimated torque as compared with Biodex by 8 N$cdot$m on average. Same-day intrarater intraclass correlation coefficients (ICCs) ranged from 0.97 to 0.98. Interrater reliability ICCs ranged from 0.83 to 0.95.nnCONCLUSION: HHD represents a reliable and valid alternative to Biodex to rank individuals on leg strength, or to assess within-person changes in leg strength over time, because of the high validity and reliability. The HHD is less suited for absolute strength assessment because of significant systematic overestimations.nnCLINICAL RELEVANCE: Clinicians are encouraged to use HHD to rank older adults on leg strength, or to assess within-person changes in leg strength over time, but not to compare readings with cut-offs or normative values.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid34666201,

title = {Impact of Magnesium on Bone Health in Older Adults: A Systematic Review and Meta-Analysis},

author = {Inge Groenendijk and Marieke Delft and Pieter Versloot and Luc J C Loon and Lisette C P G M Groot},

doi = {10.1016/j.bone.2021.116233},

issn = {1873-2763},

year  = {2022},

date = {2022-01-01},

journal = {Bone},

volume = {154},

pages = {116233},

abstract = {BACKGROUND: Magnesium plays a key role in bone health and may, therefore, represent an interesting nutrient for the prevention of bone loss and osteoporosis. The aim of this systematic review and meta-analysis was to investigate the impact of magnesium intake from any source on bone mineral density (BMD), bone mineral content (BMC), bone turnover markers, and fracture risk in older adults.nnMETHODS: A systematic search was conducted using Embase, Medline Ovid and Cochrane Central from database inception to October 2020. All studies that related magnesium intake with bone health outcomes among adults aged $geq$60 years were included. Two investigators independently conducted abstract and full-text screenings, data extractions, and risk of bias assessments. Authors were contacted for missing data.nnRESULTS: Once 787 records were screened, six cohort studies, one case-control study and five cross-sectional studies were included. Qualitative evaluation demonstrated a positive trend between higher magnesium intake and higher hip and femoral neck BMD. Meta-analysis of four studies showed a significant positive association between magnesium intake and hip BMD (pooled beta: 0.03, 95% CI: 0.01-0.06, p ¡ 0.05).nnCONCLUSIONS: This systematic review indicates that a higher magnesium intake may support an increase in hip and femoral neck BMD. Due to limited research no associations with BMD at other sites or fractures were found. There is a need for properly designed cohort studies to determine the association between magnesium intake and bone health in older adults. Next, large and long-term randomized controlled trials in older adults are needed to determine whether an increase in magnesium (supplementation) intake can improve bone health. The combination of several bone nutrients (calcium, vitamin D, protein, magnesium and potentially more) may be needed for the most optimal effect on bone health and to delay or prevent the development of osteoporosis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid34642762,

title = {Ingestion of Free Amino Acids Compared with an Equivalent Amount of Intact Protein Results in More Rapid Amino Acid Absorption and Greater Postprandial Plasma Amino Acid Availability without Affecting Muscle Protein Synthesis Rates in Young Adults in a Double-Blind Randomized Trial},

author = {Michelle E G Weijzen and Rob J J Gassel and Imre W K Kouw and Jorn Trommelen and Stefan H M Gorissen and Janneau Kranenburg and Joy P B Goessens and Marcel C G Poll and Lex B Verdijk and Luc J C Loon},

doi = {10.1093/jn/nxab305},

issn = {1541-6100},

year  = {2022},

date = {2022-01-01},

journal = {The Journal of nutrition},

volume = {152},

number = {1},

pages = {59–67},

abstract = {BACKGROUND: The rate of protein digestion and amino acid absorption determines the postprandial rise in circulating amino acids and modulates postprandial muscle protein synthesis rates.nnOBJECTIVE: We sought to compare protein digestion, amino acid absorption kinetics, and the postprandial muscle protein synthetic response following ingestion of intact milk protein or an equivalent amount of free amino acids.nnMETHODS: Twenty-four healthy, young participants (mean ± SD age: 22 ± 3 y and BMI 23 ± 2 kg/m2; sex: 12 male and 12 female participants) received a primed continuous infusion of l-[ring-2H5]-phenylalanine and l-[ring-3,5-2H2]-tyrosine, after which they ingested either 30 g intrinsically l-[1-13C]-phenylalanine-labeled milk protein or an equivalent amount of free amino acids labeled with l-[1-13C]-phenylalanine. Blood samples and muscle biopsies were obtained to assess protein digestion and amino acid absorption kinetics (secondary outcome), whole-body protein net balance (secondary outcome), and mixed muscle protein synthesis rates (primary outcome) throughout the 6-h postprandial period.nnRESULTS: Postprandial plasma amino acid concentrations increased after ingestion of intact milk protein and free amino acids (both P ¡ 0.001), with a greater increase following ingestion of the free amino acids than following ingestion of intact milk protein (P-time × treatment ¡ 0.001). Exogenous phenylalanine release into plasma, assessed over the 6-h postprandial period, was greater with free amino acid ingestion (76 ± 9%) than with milk protein treatment (59 ± 10%; P ¡ 0.001). Ingestion of free amino acids and intact milk protein increased mixed muscle protein synthesis rates (P-time ¡ 0.001), with no differences between treatments (from 0.037 ± 0.015%/h to 0.053 ± 0.014%/h and 0.039 ± 0.016%/h to 0.051 ± 0.010%/h, respectively; P-time × treatment = 0.629).nnCONCLUSIONS: Ingestion of a bolus of free amino acids leads to more rapid amino acid absorption and greater postprandial plasma amino acid availability than ingestion of an equivalent amount of intact milk protein. Ingestion of free amino acids may be preferred over ingestion of intact protein in conditions where protein digestion and amino acid absorption are compromised.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid33703944,

title = {Fragile bones of elite cyclists: to treat or not to treat?},

author = {Luuk Hilkens and Pim Knuiman and Mathieu Heijboer and Robert Kempers and Asker E Jeukendrup and Luc J C van Loon and Jan-Willem van Dijk},

doi = {10.1152/japplphysiol.01034.2020},

issn = {1522-1601},

year  = {2021},

date = {2021-07-01},

journal = {J Appl Physiol (1985)},

volume = {131},

number = {1},

pages = {26--28},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid34181488,

title = {Last Word on Viewpoint: Fragile bones of elite cyclists: to treat or not to treat?},

author = {Luuk Hilkens and Pim Knuiman and Mathieu Heijboer and Robert Kempers and Asker E Jeukendrup and Luc J C van Loon and Jan-Willem van Dijk},

doi = {10.1152/japplphysiol.00375.2021},

issn = {1522-1601},

year  = {2021},

date = {2021-07-01},

journal = {J Appl Physiol (1985)},

volume = {131},

number = {1},

pages = {34--35},

keywords = {},

pubstate = {published},

tppubtype = {article}

}