Protein Anabolic Responses to a Fed Steady State in Healthy Aging
Protein Anabolic Responses to a Fed Steady State in Healthy Aging
复制标题
DOI：
10.1093/gerona/glr036
复制
发表时间：
2011-06-01
影响因子：
5.1
通讯作者：
Morais, Jose A.
中科院分区：
文献类型：
--
作者：
Chevalier, Stephanie;Goulet, Eric D. B.;Morais, Jose A.
背景资料。随着年龄的增长，对摄食反应的蛋白质合成代谢可能会受到损害。为了确定这是否会导致肌肉损失，我们研究了健康的、无骨肉生成的老年女性的喂养状态代谢反应。方法：研究方法。对8例老年人(73 3岁)和8例年轻女性(2 4 I岁)的股外侧肌活检标本进行了[H-3]葡萄糖和蛋白质([C-13]亮氨酸)动力学测定，并对肌肉蛋白质合成率([H-2(5)]苯丙氨酸)和信号事件进行了评估。结果。两组的肌肉和瘦体重指数以及活动水平相似。在胰岛素、葡萄糖(8 mmoL/L)和氨基酸(AA；2倍空腹)输注过程中，老年女性血清胰岛素水平较低，C肽升高较少。葡萄糖摄取受到刺激，而生产也受到类似的抑制。在老年女性中，对全身蛋白质分解的抑制较少，导致AA输注率、氧化和净正蛋白平衡较低，但在调整血清胰岛素后，差异不存在。全身蛋白质合成率和肌肉蛋白质合成率也有类似的提高。磷酸化Akt(Ser473)、PRAS40(Thr246)、FOXO3a(Thr32)和rpS6(Ser240/244)的类似增加表明胰岛素/营养信号没有随着年龄的变化而改变。结论。在积极、健康的老年妇女中，全身和肌肉喂养状态的蛋白质合成代谢反应都得到了保留，葡萄糖代谢的胰岛素敏感性也得到了保留。这与其他因素是一致的，如它的稳固性，蛋白质摄入量低，以及并发疾病，是导致衰老的石棺减少的原因。
Background. Protein anabolism in response to feeding may be impaired with aging. To determine if this could contribute to muscle loss, we studied fed-state metabolic responses in healthy, non-sarcopenic elderly women. Methods. Whole-body [H-3]glucose and protein ([C-13]leucine) kinetics were measured, and muscle protein fractional synthesis rate ([H-2(5)]phenylalanine) and signaling events were assessed from vastus lateralis biopsies in eight elderly (73 3 years) and eight young women (24 I years), using a simulated fed steady-state clamp. Results. Both groups had similar muscle and lean body mass indices and activity level. During insulin, glucose (8 mmol/L), and amino acid (AA; 2x fasting) infusions, serum insulin was lower in the elderly women and C-peptide increased less. Glucose uptake was stimulated, and production suppressed similarly. Suppression of whole-body protein breakdown was less in the elderly women, leading to lower AA infusion rates, oxidation, and net positive protein balance, but differences were not present when adjusted for serum insulin. Whole-body protein synthesis and muscle protein fractional synthesis rate increased similarly. Similar increases in phosphorylated Akt(ser473), PRAS40(Thr246), FoxO3a(Thr32), and rpS6(ser240/244) indicated no alterations in insulin/nutrient signaling with aging. Conclusions. Both whole-body and muscle fed-state protein anabolic responses were preserved, as was insulin sensitivity of glucose metabolism, in active, healthy elderly women. This is consistent with other factors such Its sedentarity, low protein intake, and concurrent diseases, being responsible for the sarcopenia of aging.