CELLULAR MECHANISMS FOR SARCOPENIA IN THE ELDERLY

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。随着年龄的增长，身体蛋白质的损失会导致肌肉组织的选择性耗尽，这就是所谓的骨质疏松症。由于瘦体重的损失主要来自肌肉组织，它对维持肌肉力量和功能具有重要意义。除了对肌肉功能的严重影响外，骨质疏松症还会减少应激时可用于动员的氨基酸储备。危重病程中虚弱的患者体内氨基酸储备的减少是预后的主要决定因素。肌肉蛋白质经历不断的合成和降解。当蛋白质合成和降解的速度达到平衡时，肌肉蛋白质质量保持不变，但如果蛋白质降解超过合成，就会损失肌肉蛋白质。在组织水平上，老年人肌肉蛋白质的丧失与肌肉蛋白质合成速度的降低有关，而年轻和老年受试者之间的肌肉降解没有差异。因此，在探索老年人肌肉萎缩的机制时，考虑控制肌肉蛋白质合成的因素是很重要的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Loss of body protein occurs with advancing age with selective depletion of muscle tissue, is known as sarcopenia. Since the loss of lean body mass is primarily from muscle tissue, it has important implications for the maintenance of muscle strength and function. In addition to the serious consequences for muscle function, sarcopenia also reduces the reserve of amino acids available for mobilization in times of stress. Diminished reserve of amino acids in wasted patients during critical illness is a major determinant of outcome. Muscle protein undergoes continual synthesis and degradation. When the rates of protein synthesis and degradation are balanced, muscle protein mass is maintained, but if protein degradation exceeds synthesis, there will be a loss of muscle protein. At the tissue level, loss of muscle protein in the elderly has been associated with a reduction in the rate at which muscle protein is synthesized with no difference in muscle degradation between younger and older subjects. It is therefore important to consider the factors that control protein synthesis in muscle when seeking the mechanism of muscle wasting in the elderly.