NOVEMBER 2017

摘要

Bariatric surgery routinely results in significant weight loss in obese individuals and a concurrent remission of type 2 diabetes for many who have the disease. Quite why this happens has been the subject of numerous hypotheses and speculation. According to Grenier-Larouche et al. (p. 2743), it seems likely that yet another mechanism might be involved, namely that bariatric surgery results in complete remodeling of the way adipose tissues deal with fatty acids and that this in turn affects glycemic control and improves insulin sensitivity. They report their year-long investigation of a small group (n = 17) of severely obese individuals who underwent a bariatric surgery procedure and were then followed to determine various measures relating to obesity and diabetes. A significant weight reduction (a mean excess weight loss of 84% after 1 year) and partial or complete remission of type 2 diabetes in all of the patients was achieved. The authors also revealed a number of mechanistic changes and a picture of how adipose tissues likely change the way they handle fat following surgery. Author Andre C. Carpentier said: "What is striking in our study is the highly dynamic metabolic adaptation of lean and adipose tissues over very large changes in total body adiposity. Very early after surgery before weight loss had occurred, we saw very important improvement in hepatic insulin resistance closely associated with a reduction in adipose tissue free fatty acid spillover. However, at later stages with important weight loss, this adipose tissue mechanism was completely gone and replaced by improved lean tissue handling of free fatty acids secreted at large rates again by adipose tissues. In the end, remission of diabetes appears related to adipose tissue cell size reduction but not reduction of its free fatty acid secretion as we thought initially. This shows that the current view held by many of the link between high adipose tissue free fatty acid secretion and type 2 diabetes is too simplistic."