Circulating Spexin Decreased and Negatively Correlated with Systemic Insulin Sensitivity and Pancreatic β Cell Function in Obese Children

Objectives: Spexin (SPX) is a novel peptide that has recently emerged as an important regulatory adipokine of obesity and related metabolic disease. Little is known about its role in children. The aim of the current study was to determine the potential role of SPX in obese children and explore its relationships with obesity-related markers, insulin sensitivity and pancreatic β cell function. Method: We studied the levels of serum SPX in 40 obese and 32 normal weight pre-puberty children (mean age was 8.59 ± 1.82 and 8.15 ± 2.03 years in obesity and control groups respectively). We investigated the levels of body mass index, blood pressure, lipids, glucose, insulin, Homeostasis model assessment for insulin-resistant (HOMA-IR, HOMA for β-cell function [HOMA-β]), insulinogenic index and C-peptide index and analyzed their correlations with SPX levels. Results: SPX levels were significantly decreased in obese children compared to controls. Moreover, serum SPX levels were lower in IR obese subjects in contrast with the non-IR obese subjects. Serum SPX concentrations correlated negatively and significantly with triglycerides, systolic blood pressure, diastolic blood pressure, fasting insulin level, HOMA-IR, insulinogenic index, and HOMA-β levels in obese children. Conclusions: In summary, serum SPX levels significantly decreased in obese children and negatively correlated with insulin resistance and pancreatic β cell function indicators. Therefore, SPX may play a protective role in the process of glucose homeostasis and is closely related to β cell function in obese children.