Sleeve gastrectomy promotes sustained weight loss while increasing heat production in middle aged, obese female mice

Background Sleeve gastrectomy (SG) is currently the most frequently performed bariatric surgery in the United States. The majority of patients undergoing SG are middle aged women. Most preclinical models of bariatric surgery, however, utilize juvenile male mice. A long-term characterization of the response of mature wild type, obese female mice to SG has not been performed. Thus, we set out to characterize the response of middle aged obese female mice to SG. Methods Ten-month old C57bl/6J obese female mice were randomized to undergo SG, sham surgery without caloric restriction (SH) or sham surgery with caloric restriction to match body weight to the SG group (SWM). Body weight, body composition and glucose tolerance were matched at baseline. Mice were followed for 60 days following their respective surgeries. Results The SG group had a more pronounced percent weight loss than the SH and SWM control groups (p<0.05), while consuming more calories than the SWM group (p<0.05). The SG group had a significant improvement in glucose tolerance compared to the SH control group (p<0.05). Plasma leptin was significantly decreased in the SG and SWM group, compared to the SH group (p<0.01). Unexpectedly, FGF-21 was increased in the SH group compared to the SG and SWM groups (p<0.01), while there was no difference in plasma insulin among the three groups. Heat production was increased in the SG group compared to SWM and SH groups (p<0.001). SG also had a significantly increased mRNA expression of Uncoupling Protein 1 (UCP-1), Adiponectin and Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha (PGC1-alpha) in brown adipose tissue (BAT), compared to SWM and SH groups. Both SG and SWM groups had increased fecal lipid excretion (p<0.05), compared to the SH group. Conclusions SG in obese, middle aged female mice leads to sustained weight loss and blood glucose improvement. It appears that increased metabolism in BAT may be linked to these effects.