Brain cells damaged by obesity may contribute to Type 2 diabetes, a disease that is spreading at epidemic rates, according to a study released Wednesday.
And in unorthodox research also reported on Wednesday, doctors are exploring whether a radical type of weight-loss surgery on morbidly obese patients may also be a cure for the disease.
Diabetics do not produce enough insulin or cannot use the insulin they do make, causing wild and potentially dangerous fluctuations of glucose levels in the blood.
In a paper published by the British journal Nature, a team led by Bradford Lowell at Harvard showed that genetically-modified mice with impaired sugar-sensitive neurons developed glucose intolerance -- diabetes' core symptom.
Lowell found that the same brain cells were also defective in normal mice that had developed the disease due to obesity.
He concludes that a flaw in the brain's ability to sense glucose "might have a pathogenic role" in the development of Type 2 diabetes. If so, the way could be open to drug treatments to target the impaired cells, called pro-opiomelanocortin neurons.
The British weekly New Scientist, meanwhile, says that a team of Italian, Brazilian and French doctors are exploring an extraordinary accidental find.
In past years, surgeons have realised that a radical form of surgery on very obese patients in 98 percent of cases also causes their diabetes to vanish within a few weeks of the operation.
The symptoms disappear too quickly to be attributed to weight-loss alone.
The operation, called duodenal exclusion, consists of removing the tube connecting the stomach to the small intestine.
As a result, the stomach feeds directly into the mid-small intestine, reducing the amount of time the body has to absorb calories from food and thus helping chronically overweight patients to lose excess kilos (pounds).
Investigating the phenomenon, the multinational team have carried out duodenal exclusions on seven people with Type 2 diabetes, ranging from individuals with normal weight to those who were moderately obese.
Nine months after the operations, two patients had stopped taking anti-diabetes medication and had shown sharp drops in their blood sugar levels and insulin levels within weeks, the researchers reported. It is too soon to assess the other patients.
One of the surgeons, Francesco Rubino, speculated that the duodenum may be the source of a molecular signal secreted in response to the passage of food that is exaggerated in diabetic patients, causing insulin resistance.
Bypassing the duodenum could "silence this insulin resistance signal," he told New Scientist.
Until now, the pancreas was thought to be the key regulator of glucose levels in the body.
Rubino will report his findings at a conference next week in Portugal on surgery and obesity.
But it could take years before further trials determine whether the procedure is safe enough to become routine and identify who could benefit from it most.
Type 2 -- also called adult-onset -- diabetes has swept developed nations and is now moving quickly into developing countries that are on the fast track to prosperity, driven by high-calorie diets.
The condition is aggravated by a sedentary lifestyle, but some people may have be genetically vulnerable to obesity.
Type 1 diabetes is a rarer form of the disease that usually occurs in childhood, when insulin-making cells in the pancreas are destroyed.
If left untreated by injections of insulin, diabetes can lead to blindness, heart disease, amputations, kidney failure and death.
The disease afflicts more than 170 million people worldwide -- a number that is set to double by 2030 -- and accounts for nearly three million premature deaths every year, according to the World Health Organisation (WHO).