Insulin Resistance, Microbiota, and Fat Distribution Changes by a New Model of Vertical Sleeve Gastrectomy in Obese Rats

Abstract

Metabolic surgery improves insulin resistance and type 2 diabetes possibly because of weight loss. We performed a novel sleeve gastrectomy in rats that resects ∼80% of the glandular portion, leaving the forestomach almost intact (glandular gastrectomy [GG]) and compared subsequent metabolic remodeling with a sham operation. GG did not affect body weight, at least after 10 weeks; improved hepatic and peripheral insulin sensitivity likely through increased Akt, glycogen synthase kinase 3, and AMPK phosphorylation; and reduced ectopic fat deposition and hepatic glycogen overaccumulation. Body adipose tissue was redistributed, with reduction of intraabdominal fat. We found a reduction of circulating ghrelin levels, increased GLP-1 plasma concentration, and remodeling of gut microbiome diversity characterized by a lower relative abundance of Ruminococcus and a higher relative abundance of Lactobacillus and Collinsella These data suggest that at least in rat, the glandular stomach plays a central role in the improvement of insulin resistance, even if obesity persists. GG provides a new model of the metabolically healthy obese phenotype.

Diet change affects intestinal microbiota restoration and improves vertical sleeve gastrectomy outcome in diet-induced obese rats

“…In this work we investigated the effect of HFD, VSG (accompanied by dietary switch or not) and change of diet alone on the Sprague-Dawley rat cecal microbiota, a follow-up of our earlier work reporting on weight loss results [18]. The combined effect of diet and surgery had distinctive effects on the microbiota in line with previous reports [8,28,30]. In addition to this, an obvious effect attributable to pre-operative antibiotic prophylaxis is noted, reflected in the effects observed in the Shamoperated cohort of this study.…”

“…Nevertheless, we observed a pronounced reduction that persisted after the switch of diet alone. Alpha diversity was also affected by VSG, but to a lesser degree than by the change of diet, although VSG only removes the glandular part of the stomach and leaves the intestine intact [28]. Nonetheless, both C and D groups subjected to VSG had reduced alpha diversity, similar to what has been seen in humans and animals [41,42], but also to Sham surgery, suggesting the effects of the antibiotic Enrofloxacina were the primary cause rather than the surgery itself.…”

“…Due to the similar benefits with less severe complications VSG popularity as the preferred BS is increasing [26]. Studies in both animal models and humans have shown that BS causes changes in the microbial community, several of which show apparent correlation with the health improvements seen following BS [8,[27][28][29][30]. This is the continuation of a previous article, where rats after being fed either a control diet or HFD for 8 weeks underwent either no surgery, simulated (Sham) surgery, or VSG [18].…”

Characterization of the serum and liver proteomes in gut-microbiota-lacking mice

“…However, except for BAT index, GF group significantly decreased the indices of liver, lung, kidney, muscle and EFP than the SPF group. Basso et al demonstrated the gut microbiota can increase body fat 16. D'Aversa et al also showed that the gut microbiota not only promotes lipogenesis and VLDL production, it also facilitates storage in adipose tissue by increasing LPL activity 17.…”

Roux-Y Gastric Bypass and Sleeve Gastrectomy directly change gut microbiota composition independent of operation type

“…Persisting post-surgery microbiota changes suggest adaptation to anatomic and physiologic changes, such as reduced acid production, increased oxygen content, altered bile acid concentrations delivered to the colon, induced by the surgery. Previously reported effects of bariatric surgery on microbiota diversity have ranged from an increase in total diversity 25, 26 to absence of change and even a decrease in alpha diversity 27 . We suspect that baseline sampling in relation to crash diet may vary between studies, and might contribute to the reported differences between studies.…”