Obesity-associated hypogonadism is very prevalent in males with morbid obesity and is mostly reversed after sustained weight loss by bariatric surgery.

Because the role of lipocalin 2 (LCN2) in morbid obesity is still not well defined, the aim of this study was to evaluate the circulating levels and the expression of LCN2 in visceral (VAT) and subcutaneous adipose tissue (SAT) in severely obese (SO) women. We also analyzed its relationship with inflammatory cytokines in the same subjects. The study comprised 90 white women, 39 of whom were lean controls (BMI ≤25 kg/m2) and 51 SO (BMI ≥40 kg/m2). Both circulating and adipose tissue levels of LCN2 were quantified by enzyme‐linked immunosorbent assays. LCN2 mRNA levels from VAT and SAT were assessed by real‐time reverse transcriptase‐PCR (n = 60). LCN2 serum levels were significantly higher in the SO women than in the lean controls (P = 0.042), and were found to be strongly correlated with tumor necrosis factor receptor I (TNFR1) circulating levels. In the SO cohort, LCN2 serum levels were also associated with higher BMI values, but not with the homeostasis model assessments of insulin resistance (HOMA2‐IR). LCN2 mRNA expression was markedly higher in SO women than in lean women in both VAT (P = 0.043) and SAT (P = 0.031). In SAT, LCN2 was negatively correlated with adiponectin and adiponectin receptor‐2 expression, and positively with interleukin‐6 (IL‐6) expression. A strong positive correlation was also found between LCN2 expression and the mean diameter of adipocytes in VAT. Our results revealed that the circulating level of LCN2 is associated with obesity and BMI. LCN2 mRNA is over‐expressed in adipose tissue from SO subjects. Finally, the expression of LCN2 is strongly related to an expression profile of proinflammatory cytokines but not to insulin resistance in nondiabetic SO women.

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Vitamin D deficiency is the most prevalent long-term nutritional deficiency after SG. About half of patients show some micronutrient deficiency at medium long term, despite supplementation. A proactive follow-up is required to ensure a personalized and adequate supplementation in all surgically treated obese patients including those in which SG has been performed.

To determine the potential use of baseline circulating succinate to predict type 2 diabetes remission after bariatric surgery. RESEARCH DESIGN AND METHODS Forty-five obese patients with diabetes were randomly assigned to Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), or laparoscopic greater curvature plication. Anthropometric parameters were evaluated, and a complete biochemical analysis including circulating serum succinate concentrations was performed at baseline and 1 year after surgery. The results were externally validated in a second cohort including 88 obese patients with diabetes assigned to RYGB or SG based on clinical criteria. RESULTS Succinate baseline concentrations were an independent predictor of diabetes remission after bariatric surgery. Patients achieving remission after 1 year had lower levels of baseline succinate (47.8 [37.6-64.6] mmol/L vs. 64.1 [52.5-82.9] mmol/L; P = 0.018). Moreover, succinate concentrations were significantly decreased 1 year after surgery (58.9 [46.4-82.4] mmol/L vs. 46.0 [35.8-65.3] mmol/L, P = 0.005). In multivariate analysis, the best logistic regression model showed that baseline succinate (odds ratio [OR] 11.3, P = 0.031) and the type of surgery (OR 26.4, P = 0.010) were independently associated with remission. The C-statistic for this model was 0.899 (95% CI 0.809-0.989) in the derivation cohort, which significantly improved the prediction of remission compared with current available scores, and 0.729 (95% CI 0.612-0.846) in the validation cohort. Interestingly, patients had a different response to the type of surgery according to baseline succinate, with significant differences in remission rates. CONCLUSIONS Circulating succinate is reduced after bariatric surgery. Baseline succinate levels have predictive value for diabetes remission independently of previously described presurgical factors and improve upon the current available scores to predict remission.