Insulin resistance, microbiota, and fat distribution changes by a new model of vertical sleeve gastrectomy in obese rats

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.