BACKGROUND: Excess body fat diminishes muscle protein synthesis rates in response to hyperinsulinemic-hyperaminoacidemic clamps. However, muscle protein synthetic responses after the ingestion of a protein-dense food source across a range of body mass indexes (BMIs) have not been compared. OBJECTIVE: We compared the myofibrillar protein synthetic response and underlying nutrient-sensing mechanisms after the ingestion of lean pork between obese, overweight, and healthy-weight adults. DESIGN: Ten healthy-weight [HW; BMI (in kg/m2): 22.7 ± 0.4], 10 overweight (OW; BMI: 27.1 ± 0.5), and 10 obese (OB; BMI: 35.9 ± 1.3) adults received primed continuous l-[ring-13C6]phenylalanine infusions. Blood and muscle biopsy samples were collected before and after the ingestion of 170 g pork (36 g protein and 3 g fat) to assess skeletal muscle anabolic signaling, amino acid transporters [large neutral and small neutral amino acid transporters (LAT1, SNAT2) and CD98], and myofibrillar protein synthesis. RESULTS: At baseline, OW and OB groups showed greater relative amounts of mammalian target of rapamycin complex 1 (mTORC1) protein than the HW group. Pork ingestion increased mTORC1 phosphorylation only in the HW group (P = 0.001). LAT1 and SNAT2 protein content increased during the postprandial period in all groups (time effect, P < 0.05). Basal myofibrillar protein synthetic responses were similar between groups (P = 0.43). However, myofibrillar protein synthetic responses (0-300 min) were greater in the HW group (1.6-fold; P = 0.005) after pork ingestion than in the OW and OB groups. CONCLUSIONS: There is a diminished myofibrillar protein synthetic response to the ingestion of protein-dense food in overweight and obese adults compared with healthy-weight controls. These data indicate that impaired postprandial myofibrillar protein synthetic response may be an early defect with increasing fat mass, potentially dependent on altered anabolic signals, that reduces muscle sensitivity to food ingestion. This trial was registered at clinicaltrials.gov as NCT02613767.
BACKGROUND: Excess body fat diminishes muscle protein synthesis rates in response to hyperinsulinemic-hyperaminoacidemic clamps. However, muscle protein synthetic responses after the ingestion of a protein-dense food source across a range of body mass indexes (BMIs) have not been compared. OBJECTIVE: We compared the myofibrillar protein synthetic response and underlying nutrient-sensing mechanisms after the ingestion of lean pork between obese, overweight, and healthy-weight adults. DESIGN: Ten healthy-weight [HW; BMI (in kg/m2): 22.7 ± 0.4], 10 overweight (OW; BMI: 27.1 ± 0.5), and 10 obese (OB; BMI: 35.9 ± 1.3) adults received primed continuous l-[ring-13C6]phenylalanine infusions. Blood and muscle biopsy samples were collected before and after the ingestion of 170 g pork (36 g protein and 3 g fat) to assess skeletal muscle anabolic signaling, amino acid transporters [large neutral and small neutral amino acid transporters (LAT1, SNAT2) and CD98], and myofibrillar protein synthesis. RESULTS: At baseline, OW and OB groups showed greater relative amounts of mammalian target of rapamycin complex 1 (mTORC1) protein than the HW group. Pork ingestion increased mTORC1 phosphorylation only in the HW group (P = 0.001). LAT1 and SNAT2 protein content increased during the postprandial period in all groups (time effect, P < 0.05). Basal myofibrillar protein synthetic responses were similar between groups (P = 0.43). However, myofibrillar protein synthetic responses (0-300 min) were greater in the HW group (1.6-fold; P = 0.005) after pork ingestion than in the OW and OB groups. CONCLUSIONS: There is a diminished myofibrillar protein synthetic response to the ingestion of protein-dense food in overweight and obese adults compared with healthy-weight controls. These data indicate that impaired postprandial myofibrillar protein synthetic response may be an early defect with increasing fat mass, potentially dependent on altered anabolic signals, that reduces muscle sensitivity to food ingestion. This trial was registered at clinicaltrials.gov as NCT02613767.
Authors: N Zeng; U Prodhan; R F D'Souza; F Ramzan; S M Mitchell; P Sharma; S O Knowles; N C Roy; A Sjödin; K-H Wagner; A M Milan; D Cameron-Smith; C J Mitchell Journal: J Nutr Health Aging Date: 2019 Impact factor: 4.075
Authors: Nathan Hodson; Daniel W D West; Andrew Philp; Nicholas A Burd; Daniel R Moore Journal: Am J Physiol Cell Physiol Date: 2019-08-28 Impact factor: 4.249
Authors: Stephan van Vliet; Joseph W Beals; Andrew M Holwerda; Russell S Emmons; Joy P Goessens; Scott A Paluska; Michael De Lisio; Luc J C van Loon; Nicholas A Burd Journal: J Appl Physiol (1985) Date: 2019-11-14
Authors: Joseph W Beals; Sarah K Skinner; Colleen F McKenna; Elizabeth G Poozhikunnel; Samee A Farooqi; Stephan van Vliet; Isabel G Martinez; Alexander V Ulanov; Zhong Li; Scott A Paluska; Nicholas A Burd Journal: J Physiol Date: 2018-09-30 Impact factor: 5.182
Authors: Nathan Hodson; Chris McGlory; Sara Y Oikawa; Stewart Jeromson; Zhe Song; Markus A Rüegg; D Lee Hamilton; Stuart M Phillips; Andrew Philp Journal: Am J Physiol Cell Physiol Date: 2017-09-27 Impact factor: 4.249
Authors: Katon A Kras; Nyssa Hoffman; Lori R Roust; Shivam H Patel; Chad C Carroll; Christos S Katsanos Journal: J Clin Endocrinol Metab Date: 2017-12-01 Impact factor: 5.958
Authors: Richie D Barclay; Joseph W Beals; Jenny Drnevich; Brian S Imai; Peter M Yau; Alexander V Ulanov; Neale A Tillin; Martha Villegas-Montes; Scott A Paluska; Peter W Watt; Michael De Lisio; Nicholas A Burd; Richard W Mackenzie Journal: Metabolism Date: 2019-10-31 Impact factor: 8.694