The role of obestatin in roux-en-Y gastric bypass-induced remission of type 2 diabetes mellitus

Metabolic and Endocrine Consequences of Bariatric Surgery

Obesity is one of the most serious worldwide epidemics of the twenty-first century according to the World Health Organization. Frequently associated with a number of comorbidities, obesity threatens and compromises individual health and quality of life. Bariatric surgery (BS) has been demonstrated to be an effective treatment to achieve not only sustained weight loss but also significant metabolic improvement that goes beyond mere weight loss. The beneficial effects of BS on metabolic traits are so widely recognized that some authors have proposed BS as metabolic surgery that could be prescribed even for moderate obesity. However, most of the BS procedures imply malabsorption and/or gastric acid reduction which lead to nutrient deficiency and, consequently, further complications could be developed in the long term. In fact, BS not only affects metabolic homeostasis but also has pronounced effects on endocrine systems other than those exclusively involved in metabolic function. The somatotropic, corticotropic, and gonadal axes as well as bone health have also been shown to be affected by the various BS procedures. Accordingly, further consequences and complications of BS in the long term in systems other than metabolic system need to be addressed in large cohorts, taking into account each bariatric procedure before making generalized recommendations for BS. In this review, current data regarding these issues are summarized, paying special attention to the somatotropic, corticotropic, gonadal axes, and bone post-operative health.

The role of obestatin in Roux-en-Y gastric bypass surgery in the obese, type 2 diabetes Zucker rat

AIMS

Roux-en-Y gastric bypass (RYGB) is a novel therapy for diabetes and the exact mechanisms of this procedure remain unclear. Obestatin is an important gut hormone. We aimed to explore the role of obestatin in the therapeutic mechanism of RYGB.

METHODS

Twenty obese Zucker rats and twenty Wistar rats were randomly assigned to two groups: RYGB and sham surgery. We evaluated plasma obestatin and insulin levels pre- and post-RYGB. Additionally, obestatin expression levels in the gastrointestinal tract were assessed using immunohistochemical staining.

RESULTS

In Zucker rats, plasma obestatin and insulin levels gradually increased after RYGB. At post-operation week 7, plasma levels of obestatin were higher in the RYGB group than the sham operation group, and fasting plasma insulin levels were significantly increased the in RYGB group compared with the sham operation group. Furthermore, we observed a positive relationship between obestatin and insulin plasma levels. Among 10 zucker rats, high expression of obestatin was only seen in the jejunum of 2 rats before the operation; however, high expression of obestatin was seen in the Roux limb of 8 rats and in the ileum of 7 rats after RYGB. The expression of obestatin was significantly higher in the intestine in the RYGB group than the sham operation group postoperatively.

CONCLUSIONS

We propose that obestatin maybe a potential mediator to improve glucose homeostasis after RYGB. The increase of obestatin secretion may be an important mechanism through which RYGB alleviates obesity and type 2 diabetes mellitus.