Regulation of ghrelin is related to estimated insulin sensitivity in obese children

Abstract

Objective: To investigate whether ghrelin concentrations and their changes during weight loss in obese children are associated with parameters of glucose and insulin metabolism. Design: Total plasma ghrelin, insulin and glucose were measured during oral glucose tolerance testing before and after dietinduced weight loss over 6 weeks. Setting: In-patient rehabilitation program in a pediatric hospital. Participants: Twenty-three obese children (age 10-16 years) and 11 normal weight controls (age 10-15 years). Outcome measures: Changes in ghrelin concentrations during weight loss and correlation analysis of changes in ghrelin and changes in parameters of glucose and insulin metabolism. After data collection, subgroup analysis of obese patients with high, medium and low estimated insulin sensitivity whole-body insulin sensitivity index (WBISI) was performed. Results: Weight loss increased the area under the curve (AUC) of ghrelin by 26% (Po0.001). The increase in ghrelin AUC correlated significantly with improved estimated insulin sensitivity (WBISI) (r ¼ 0.69, Po0.001). The independent predicting effect of WBISI was confirmed in multivariate analysis. In children with low WBISI, ghrelin reached the level of control values after weight loss. In children with high WBISI, ghrelin increased markedly above control levels. Conclusions: Changes in ghrelin are independently associated with changes in glucose and insulin metabolism. The increase in plasma ghrelin above control levels was limited to obese children with high WBISI.

The Effect of Multidisciplinary Lifestyle Intervention on the Pre- and Postprandial Plasma Gut Peptide Concentrations in Children with Obesity

“…Various studies have shown an increase of fasting plasma ghrelin levels after weight loss in obese children [8, 10, 13]. However, the amount of weight lost was substantially greater in these studies than in ours.…”

“…Generally, the plasma ghrelin concentration of obese children is lower in fasting condition [6–10], whereas the decline in response to glucose ingestion varies as a function of insulin sensitivity; the decline appears to be less profound in insulin resistant obese children [6, 11], although the data are equivocal [12]. Weight loss tends to normalize circulating ghrelin levels [8, 10, 13], although this is still a subject for debate [5, 14]. …”

Ghrelin and PYY levels in adolescents with severe obesity: effects of weight loss induced by long-term exercise training and modified food habits

“…In particular, Zou et al (2009) showed that ghrelin levels increase after only 1 month of a very strict weight reduction programme, including 3 h of aerobic exercises everyday and a daily calorie intake controlled at about 1,300-1,600 kcal. To the best of our knowledge, only one study reported an increase in ghrelin concentrations after weight loss in adolescents of similar age to our study (Krohn et al 2006). However, Krohn's study was conducted over a period of only 6 weeks in adolescents who did not have severe obesity (BMI z score of 2.85).…”

Putative Effects of Obesity on Linear Growth and Puberty

“…Ghrelin levels in obese children are lower than in normal-weight children, and the levels are proportionate to the degree of insulin resistance [28], suggesting that ghrelin has a role in limiting food intake in the obese insulin-resistant individual. With weight loss, a rise in ghrelin occurs along with a decline in insulin and an increase in insulin sensitivity [29]. …”