Rapid Reversal of Diabetes After Gastric Banding Surgery

New research from Australia has demonstrated a reversal of diabetes in some obese individuals and a dramatic improvement of glucose tolerance in others within 12 weeks after undergoing gastric banding surgery.

Gastric banding surgery involves the laparoscopic placement of an inflatable band between the esophagus and the stomach, which enables patients to only eat small amounts of food slowly. It is considered the least invasive and safest form of weight loss surgery.

There has been strong evidence indicating that bariatric surgery is effective at optimizing diabetes control. “Prior studies have shown rapid improvement, but only through more invasive and extreme surgery types, such as gastric bypass,” said lead study author Katherine Samaras, MBBS (Hons), PhD, FRACP, Professor of Medicine, Garvan Institute of Medical Research and St Vincent’s Hospital, Sydney, Australia, in an interview with Consultant360.

“We have shown for the first time that gastric banding normalizes blood glucose levels in type 2 diabetes within 2 weeks of surgery,” she added. Samaras and colleagues studied 15 obese patients with type 2 diabetes or impaired glucose tolerance (IGT) who underwent laparoscopic adjustable gastric banding surgery.

Measurements including fasting glucose, oral glucose insulin sensitivity (OGIS) index, and glucose levels 2 hours after a 75-g oral load were taken before surgery and at 2 and 12 weeks after surgery.

Additionally, subcutaneous and visceral adipose tissues were collected at the patients’ surgery, and macrophage number and activation were measured. At 2 and 12 weeks, researchers noted significant reductions in fasting glucose and 2-hour glucose levels as well as improved OGIS. Further, 80% of individuals with diabetes reverted to normal glucose tolerance or IGT and all individuals with IGT had normalized glucose tolerance at 12 weeks.

“We have also shown for the first time that the degree of improvement in glucose was related to the degree of improvement in circulating inflammation, which is mediated by our circulating white cells,” said Samaras. “This suggests that our metabolism and immune system are linked, possibly by our food intake.”

When asked to comment on the significance of their study findings, Samaras explained that their findings “enlarge the field of potential strategies to help manage obesity-related type 2 diabetes” and they demonstrate that “diabetes can be very rapidly controlled by enduring energy restriction, in this case using gastric banding.”

The study was successful in improving obesity-related type 2 diabetes because, as Dr. Samaras explained, bariatric surgery forces individuals to restrict their energy intake rigorously and consistently. She also pointed out that patients with type 2 diabetes often still have some insulin production. “When we cut food intake substantially, this allows the demands of diet to be met by the insulin the body is capable of producing,” she said.

“This occurs very quickly, when there is only very modest weight reduction, even in morbidly obese people.” Samaras noted that most of the study participants had longstanding diabetes of at least 5 years duration, which shows that even individuals with long-term diabetes can experience benefits from cutting back their food intake. She pointed out that bariatric surgery is not the only means to ensure long-term energy restriction.

“Diet works just as well, as long as the effort and rigor is maintained,” she said. “However, when people fall off the track, glucose levels will rise.” She commented that, although this can also occur after bariatric surgery, “the surgery makes it difficult for that to happen frequently or regularly.”

“Bariatric surgery is an effective treatment option for obese people with type 2 diabetes, where concerted efforts for reduced energy intake and weight loss have failed,” Samaras said. “That's assuming that people have received individualized advice and supervision by medical practitioners and allied health professionals with expertise in weight reduction. If they haven't, that should always be the first step.”

“Our findings give hope to people who struggle in their fight against diabetes and obesity, in demonstrating the rapid effectiveness of bariatric surgery in normalizing glucose tolerance in the majority of people with obesity-related diabetes,” she said.

According to Samaras, their future research will continue to explore the nexus between the immune system and metabolism, particularly in genetic regulation of obesity. “We have known for some time, for example, that some people are genetically susceptible to obesity and that there are certain environmental factors that magnify that susceptibility and others that downplay it,” she explained.

-Meredith Edwards White

Reference

Samaras K, Viardot A, Botelho NK, Jenkins A, Lord RV. Immune cell-mediated inflammation and the early improvements in glucose metabolism after gastric banding surgery. Diabetologia. 2013 Sep 13. [Epub ahead of print]