Evaluation of serum xenin and ghrelin levels and their relationship with nonalcoholic fatty liver disease and insulin resistance in obese adolescents

Aim Xenin is a peptide of the neurotensin/xenopsin/xenin family secreted from gastric cells and other tissues. The first aim of this study was to investigate the serum xenin and ghrelin levels in obese children and compare the patients with healthy controls. The second aim was to compare the xenin levels in patients with nonalcoholic fatty liver disease (NAFLD) and also with insulin resistance with the patients without these complications. Methods 62 obese adolescents (27 with NAFLD) and 32 healthy controls were enrolled in the study. Obesity was defined as a body mass index exceeding the 95th percentile for the patients' age and sex. NAFLD was diagnosed via ultrasonographic examination. The insulin resistance was calculated by a homeostasis model assessment (HOMA-IR) index. Serum xenin and ghrelin levels were assessed by enzyme-linked immunosorbent assay. Results The mean serum xenin concentration was significantly higher in obese adolescents than the healthy peers (68.15 +/- 0.63 vs 16.54 +/- 0.07 pg/mL, p = 0.000). Serum xenin levels were not different between the patients with and without NAFLD and also between the patients with and without IR (p > 0.05). There was a positive correlation between xenin levels and relative weight (r = 0.663, p < 0.001) and HOMA-IR (r = 0.612, p < 0.001). Ghrelin was negatively correlated with relative weight (r = -0.283, p < 0.05). Conclusions In this study, serum xenin levels of both groups of obese patients were found higher than controls. On the other hand, xenin levels were not different in patients with and without NAFLD. High levels of xenin may be in relation with obesity.