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Foregut exclusion may help explain early diabetes remission following bariatric surgery
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SAN FRANCISCO — Foregut exclusion plays a central role in improving glycemic control in patients with type 2 diabetes following Roux-en-Y gastric bypass surgery, according to research presented at the American Diabetes Association’s 74th Scientific Sessions.
The findings from a proof-of-concept model utilizing a gastronomy tube (G-tube) support the notion that the postprandial glucose regulation observed early on following Roux-en-Y gastric bypass (RYGB) is independent of weight loss.
“In obese patients with type 2 diabetes, we think that adaptations arising from the foregut exclusion can provide the basis for exploring mechanisms for understanding the remission of type 2 diabetes,” John Kirwan, PhD, of the department of gastroenterology and hepatology at Cleveland Clinic in Ohio, said during his presentation.
Kirwan and colleagues evaluated 14 patients (HbA1c, 7.5±0.3% and BMI, 49±2; three men, 11 women) with type 2 diabetes who had a G-tube placed at the time of RYGB.
The researchers evaluated glucose metabolism and insulin secretion using oral and G-tube feedings; patients received mixed-meal tolerance tests (MMTT) 1 week before and approximately 2 weeks after surgery. The oral and G-tube feedings occurred on alternate days and in random order.
Weight loss after surgery was approximately 7% (P<.01) and fasting blood glucose and insulin decreased (P<0.05) compared with baseline, Kirwan showed.
“We think since the weight loss is similar for both of these post-op trials, the effects that we’re seeing here in terms of differences in responses are not due to the weight loss, per se,” Kirwan said.
During the MMTT, plasma glucose responses were significantly lower after the oral and G-tube feedings compared with baseline (P<.05). Insulin responses to MMTT, however, were significantly higher with oral ingestion (P<.05) — an effect that was reversed when nutrients were directly into the stomach through the G-tube.
C-peptide responses to MMTT after RYGB showed a pattern similar to insulin. Beta-cell function improved significantly after oral feedings (P<.05), but with feeding through the G-tube, the effect was mitigated.
“This provides us with good basis for a tool to really go after the mechanisms,” Kirwan said. “There are potentially multiple mechanisms at play here. This is really such a big hammer to hit the body with that there’s multiple systems affected.”
For More Information: Kirwan JP. Abstract 101-OR. Presented at: American Diabetes Association’s 74th Scientific Sessions; June 13-17, 2014; San Francisco.
Disclosures: Kirwan reported no relevant disclosures.