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

Abstract 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/m 2 ). 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 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.