Basal protein synthesis rates differ between vastus lateralis and rectus abdominis muscle

Journal of Cachexia Sarcopenia and Muscle, vol. 12, pp. 769–778

Abstract

Abstract Background In vivo muscle protein synthesis rates are typically assessed by measuring the incorporation rate of stable isotope labelled amino acids in skeletal muscle tissue collected from vastus lateralis muscle. It remains to be established whether muscle protein synthesis rates in the vastus lateralis are representative of muscle protein synthesis rates of other muscle groups. We hypothesized that post‐absorptive muscle protein synthesis rates differ between vastus lateralis and rectus abdominis , pectoralis major , or temporalis muscle in vivo in humans. Methods Twenty‐four patients (62 ± 3 years, 42% female), scheduled to undergo surgery, participated in this study and underwent primed continuous intravenous infusions with l ‐[ring‐ 13 C 6 ]‐phenylalanine. During the surgical procedures, serum samples were collected, and muscle tissue was obtained from the vastus lateralis as well as from the rectus abdominis , pectoralis major , or temporalis muscle. Fractional mixed muscle protein synthesis rates (%/h) were assessed by measuring the incorporation of l ‐[ring‐ 13 C 6 ]‐phenylalanine into muscle tissue protein. Results Serum l ‐[ring‐ 13 C 6 ]‐phenylalanine enrichments did not change throughout the infusion period. Post‐absorptive muscle protein synthesis rates calculated based upon serum l ‐[ring‐ 13 C 6 ]‐phenylalanine enrichments did not differ between vastus lateralis and rectus abdominis (0.032 ± 0.004 vs. 0.038 ± 0.003%/h), vastus lateralis and pectoralis major , (0.025 ± 0.003 vs. 0.022 ± 0.005%/h) or vastus lateralis and temporalis (0.047 ± 0.005 vs. 0.043 ± 0.005%/h) muscle, respectively ( P > 0.05). When fractional muscle protein synthesis rates were calculated based upon tissue‐free l ‐[ring‐ 13 C 6 ]‐phenylalanine enrichments as the preferred precursor pool, muscle protein synthesis rates were significantly higher in rectus abdominis (0.089 ± 0.008%/h) compared with vastus lateralis (0.054 ± 0.005%/h) muscle ( P < 0.01). No differences were observed between fractional muscle protein synthesis rates in vastus lateralis and pectoralis major (0.046 ± 0.003 vs. 0.041 ± 0.008%/h) or vastus lateralis and temporalis (0.073 ± 0.008 vs. 0.083 ± 0.011%/h) muscle, respectively. Conclusions Post‐absorptive muscle protein synthesis rates are higher in rectus abdominis when compared with vastus lateralis muscle. Post‐absorptive muscle protein synthesis rates do not differ between vastus lateralis and pectoralis major or temporalis muscle. Protein synthesis rates in muscle tissue samples obtained during surgery do not necessarily represent a good proxy for appendicular skeletal muscle protein synthesis rates.

Authors 8

1. Joey S.J. Smeets

   Maastricht University Medical Centre

   Affiliation as printed

   Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism Maastricht University Medical Centre+ Maastricht The Netherlands

   Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands

2. Astrid M. H. Horstman

   Maastricht University Medical Centre

   Affiliation as printed

   Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism Maastricht University Medical Centre+ Maastricht The Netherlands

   Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands

3. David P.J. van Dijk

   Maastricht University Medical Centre

   Affiliation as printed

   Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism Maastricht University Medical Centre+ Maastricht The Netherlands

   Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands

4. Astrid G.M. van Boxtel

   Catharina Ziekenhuis

   Affiliation as printed

   Department of Cardiothoracic Surgery Catharina Hospital Eindhoven The Netherlands

   Department of Cardiothoracic Surgery, Catharina Hospital, Eindhoven, The Netherlands

5. Joost Ter Woorst

   Catharina Ziekenhuis

   Affiliation as printed

   Department of Cardiothoracic Surgery Catharina Hospital Eindhoven The Netherlands

   Department of Cardiothoracic Surgery, Catharina Hospital, Eindhoven, The Netherlands

6. Steven W.M. Olde Damink Aachen Department of General, Visceral and Transplantation Surgery

   Maastricht University Medical Centre · Universitätsklinikum Aachen · RWTH Aachen University

   Affiliation as printed

   Department of General, Visceral and Transplantation Surgery RWTH University Hospital Aachen Aachen Germany

   Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism Maastricht University Medical Centre+ Maastricht The Netherlands

   Department of General, Visceral and Transplantation Surgery, RWTH University Hospital Aachen, Aachen, Germany

   Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands

7. Olaf E. M. G. Schijns

   Maastricht University Medical Centre · Maastricht University

   Affiliation as printed

   Academic Center for Epileptology, location Maastricht Maastricht University Medical Centre+ Maastricht The Netherlands

   Department of Neurosurgery Maastricht University Medical Centre+ Maastricht The Netherlands

   School of Mental Health and Neuroscience (MHeNS) Maastricht University Maastricht The Netherlands

   Academic Center for Epileptology, location Maastricht, Maastricht University Medical Centre+, Maastricht, The Netherlands

   Department of Neurosurgery, Maastricht University Medical Centre+, Maastricht, The Netherlands

   School of Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands

8. Luc J. C. van Loon corresponding

   Maastricht University Medical Centre

   Affiliation as printed

   Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism Maastricht University Medical Centre+ Maastricht The Netherlands

   Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands