Effects of age, malnutrition and refeeding on the expression and secretion of ghrelin

Background & aims: Anorexia is frequent in the malnourished elderly. We studied the effects of age, nutritional status and refeeding on the expression and secretion of the orexigenic peptide ghrelin. Methods: Four groups were prospectively enrolled: 11 undernourished elderly (80 +/- 6 y, BMI: 17.4 +/- 1.9 [Mean +/- SD]), nine well-nourished elderly (76 +/- 9 y, 23.5 +/- 2.0), 10 undernourished young (26 +/- 6 y, 15.1 +/- 1.9) and 10 well-nourished young (34 +/- 8 y, 22.2 +/- 2.7). Fasting and postprandial. plasma ghrelin and other hormones (every 30 min) were measured at baseline and after a 21-day enteral. nutrition in malnourished patients. Gastric ghrelin mRNA levels were measured by RT-PCR at baseline in all. subjects. Results: Ghrelin was significantly higher in undernourished (2151 +/- 871 ng/L) than in well-nourished (943 389 ng/L) adults, whereas there were no differences between undernourished (1544 +/- 758 ng/L) and well-nourished (1154 +/- 541 ng/L) elderly. Refeeding did not influence ghrelin levels. Gastric ghrelin mRNA levels were similar in all groups. Conclusions: There is an absence of malnutrition-induced increase of plasma ghrelin levels in elderly subjects. This feature, post-transcriptional, may be important in the tack of adaptation of elderly subjects to malnutrition. (C) 2008 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.