Roux-en-Y gastric bypass surgery in youth with severe obesity: 1-year longitudinal changes in spexin

Background: Spexin is a novel peptide predominantly produced in human white adipose tissue and has recently been implicated as a potential signal in the regulation of body weight, energy homeostasis, and satiety. The effect of bariatric surgery on spexin is unknown. Objectives: To study the effect of Roux-en-Y gastric bypass (RYGB) surgery on endogenous spexin concentration and various risk factors of type 2 diabetes and cardiovascular disease in youth with severe obesity. Setting: University hospital, United States Methods: Spexin, body mass index (BMI), insulin, glucose, total and high molecular weight adiponectin, leptin, and high sensitivity C- reactive protein were measured longitudinally (baseline, 6 mo, and 12 mo) after RYGB surgery in girls with severe obesity (n = 12; age = 16.7 ± 1.5 years; BMI = 51.6 ± 2.9 kg/m²). Results: Serum spexin concentration increased (P =.01) at 6 months after surgery and stabilized afterward. Spexin level correlated negatively with homeostatic model assessment insulin resistance, HOMA-IR (Spearman correlation r = −.796, P <.001) and positively with high molecular weight adiponectin (Spearman correlation r =.691, P =.011). The change in spexin concentration, from baseline to 6 months after surgery, was inversely correlated with the corresponding change in BMI (Spearman correlation r = −.573, P =.051). Furthermore, the 6-month changes in spexin and HOMA-IR were inversely correlated (slope [standard error, SE] = −.0084 (.0019), P =.001)], even after adjusting for the change in BMI. Conclusions: The enhancement of circulating spexin concentration in response to RYGB and correlations with beneficial postoperative changes in various adipokines in youth are novel findings that require further validation.