老年人血浆ghrelin和瘦素水平改变与老年性厌食的关联

目的研究老年人与摄食相关的激素ghrelin、瘦素、胰岛素的变化和相互关系,以及它们对老年人的食欲和摄食的影响。方法用放射免疫法测定健康年轻人(18～25岁)和老年人(60～78岁)血浆ghrelin、瘦素和胰岛素浓度。结果老年组血浆ghrelin浓度低于年轻组(P=0.027),与BMI负相关(r=-0.772,P<0.01)。老年组血浆瘦素浓度高于年轻组(P<0.001),与BMI正相关(r=0.703,P<0.01)。血浆ghrelin与瘦素负相关(r=-0.636,P<0.01)。老年组血浆胰岛素浓度与年轻组差异无显著性(P=0.186),血浆胰岛素浓度与BMI、血浆ghrelin及瘦素浓度均无明显相关。结论老年人循环中食欲减退的信号(瘦素)增强,而促进食欲的信号(ghrelin)减弱,可能是对BMI随年龄增长而产生的适应性反应,由此引起的饱感延长、饥饿感受抑可能是老年性厌食的诱因。

Relationship of changes of plasma ghrelin and leptin levels in old people and anorexia aging

Aim] To investigate the changes and relationships of plasma ghrelin, leptin and insulin levels in older people and their influence on appitie and food intake in old people. Methods] Plasma ghrelin, leptin and insulin levels of young (18~25 years) and old (60~78 years) healthy subjects were measured by radioinnunoassay. Results] Mean plasma ghrelin concentrations in older subjects were lower than those present in young subjects (P =0.027). The mean plasma ghrelin concentrations in all subjects were negatively correlated with BMI(r =-0.772, P <0.01). Mean plasma leptin concentrations in older subjects were higher than those present in young subjects (P <0.001). The mean plasma leptin concentrations in all subjects were positively correlated with BMI (r =0.703, P <0.01). There was a significant negative correlation between plasma ghrelin and leptin levels in all subjects (r =-0.636, P <0.01). Plasma insulin concentrations were not different in older and young groups. There were no significant correlations between plasma insulin levels and BMI, plasma ghrelin and leptin levels. Conclusions] In healthy old people, anorexigenic signals prevail over orexigenic signals, and this is perhaps an adopted response to the age related increasing of BMI, and they contribute to prolonged satiety and inhibition of hunger. This condition may lead to anorexia of aging in the elder.