In obese patients with type 2 diabetes, gastric bypass surgery changes the postprandial response, improving glucose tolerance, β-cell function, and insulin sensitivity while worsening endogenous glucose production in response to a stimulus, according to a study published online ahead of print in Diabetes.
Stefania Camastra, MD, of the University of Pisa in Italy, and colleagues administered a mixed meal to 10 obese patients with type 2 diabetes and 11 obese patients without diabetes before and one year after gastric bypass surgery to examine glucose tolerance and insulin sensitivity.
The researchers found that after surgery, both groups had a biphasic oral glucose appearance, postprandial glucose levels, and insulin secretion. In patients with type 2 diabetes, fasting and postprandial glucose levels were lower and peripheral insulin sensitivity increased in proportion to weight loss after surgery. Although β-cell glucose sensitivity doubled, sensitivity did not normalize compared with nonsurgical obese and lean controls. During the mixed meal, endogenous glucose production was less suppressed due to a relative hyperglucagonemia and a rapid fall in plasma glucose and insulin levels.
“We conclude that in type 2 diabetes, bypass surgery changes the postprandial response to a dumping-like pattern, improves glucose tolerance, β-cell function, and peripheral insulin sensitivity but worsens endogenous glucose output in response to a physiological stimulus,” Dr. Camastra and colleagues wrote.