Serum Vaspin Concentrations in Relation to Insulin Sensitivity Following RYGB-Induced Weight Loss

Recently, vaspin was identified as a novel adipokine with insulin-sensitizing effects that might be implicated in endogenous glucose regulation. Our objective was to evaluate the impact of acute weight loss and metabolic changes on serum vaspin concentrations in morbidly obese subjects following laparoscopic Roux-en-Y gastric bypass (RYGB) surgery. Longitudinal, clinical intervention study in 33 morbidly obese subjects before and 12 months after RYGB was conducted. Fasting serum concentrations of vaspin were measured by a commercially available ELISA and correlated with BMI, parameters of insulin sensitivity, and other biochemical measurements. Fasting insulin sensitivity was estimated using the homeostasis model assessment (HOMA) of insulin resistance. RYGB-induced weight loss resulted in a reduction of circulating vaspin, leptin, insulin, and C-peptide levels as well as of BMI, HbA1c, and HOMA (p < 0.0001, respectively). Changes in serum vaspin concentrations correlated positively with those in HOMA, insulin, C-peptide, HbA1c, and leptin (p < 0.05, respectively) levels. The association between percent change of vaspin and HOMA remained significant even after the adjustment for RYGB-induced changes in BMI. Following RYGB surgery, changes in serum vaspin concentrations correlate significantly with the reduction of circulating leptin, insulin, and C-peptide levels and with the amelioration of insulin sensitivity. However, further studies have to elucidate whether vaspin is only a biomarker for body-weight-related changes of insulin sensitivity or whether it is implicated in the regulation of human glucose homeostasis.