School of Human Development and Health, Faculty of Medicine, University of Southampton and NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton, U.K.
Center for Translational Research in Aging & Longevity, Texas A&M University, College Station, TX, U.S.A.
Clin Sci (Lond). 2022 Oct 14;136(19):1425-1431. doi: 10.1042/CS20211171.
In 1982 and 2011, Clinical Science published papers that used infusion of stable isotope-labeled amino acids to assess skeletal muscle protein synthesis in the fasted and fed state and before and after a period of increased intake of omega-3 fatty acids, respectively; both of these papers have been highly cited. An overview of the study designs, key findings and novel features, and a consideration of the lasting impact of these two papers is presented. The earlier paper introduced stable isotope tracer approaches in humans that showed consuming a meal will increase whole body oxidation, synthesis, and breakdown of protein, but that protein synthesis is greater than breakdown resulting in net accumulation of protein. The paper also demonstrated that consuming a meal promotes net protein synthesis in skeletal muscle. The later paper introduced the concept that omega-3 polyunsaturated fatty acids are able to improve anabolism by reporting that 8 weeks consumption of high-dose omega-3 fatty acids by healthy young and middle-aged adults increased skeletal muscle protein synthesis during a hyperaminoacidemic-hyperinsulinemic clamp compared with what was seen during the clamp at study entry. Omega-3 fatty acids also increased the phosphorylation of important signaling proteins in muscle, including mammalian target of rapamycin, p70s6k, and Akt, during the clamp. These two papers remain relevant because they offer experimental approaches to study human (patho)physiology in different contexts, they present novel insights into the impact of nutritional state (feeding) and specific nutrients (omega-3 fatty acids) on muscle protein synthesis, and they suggest ways to explore the potential of interventions to help prevent and reverse the age-, disease-, and disuse-associated decline in muscle mass.
1982 年和 2011 年，《临床科学》发表了两篇论文，分别使用稳定同位素标记的氨基酸输注来评估空腹和进食状态下以及在一段时间内增加摄入 ω-3 脂肪酸前后的骨骼肌蛋白质合成；这两篇论文都被高度引用。本文概述了这些研究设计、主要发现和新颖特征，并考虑了这两篇论文的持久影响。早期的论文介绍了人类稳定同位素示踪剂方法，表明进食会增加全身氧化、合成和蛋白质分解，但蛋白质合成大于分解，导致蛋白质净积累。该论文还表明，进食可促进骨骼肌的净蛋白质合成。后来的论文引入了 ω-3 多不饱和脂肪酸能够改善合成代谢的概念，报告称健康的年轻和中年成年人连续 8 周高剂量摄入 ω-3 脂肪酸可增加高氨基酸血症-高胰岛素血症钳夹期间的骨骼肌蛋白质合成，与钳夹开始时相比。ω-3 脂肪酸还增加了肌肉中重要信号蛋白的磷酸化，包括哺乳动物雷帕霉素靶蛋白、p70s6k 和 Akt。这两篇论文仍然具有相关性，因为它们提供了实验方法来研究不同背景下的人类（病理）生理学，它们提出了关于营养状态（喂养）和特定营养素（ω-3 脂肪酸）对肌肉蛋白质合成的影响的新见解，并提出了探索干预措施潜力的方法，以帮助预防和逆转与年龄、疾病和不活动相关的肌肉质量下降。
