Unhooking the Obesity-Diabetes Connection

[Guest guest]

Unhooking the Obesity-Diabetes Connection

SUNDAY, July 26 (HealthDay News) -- Scientists may be closer to solving a

medical mystery with huge implications for personal and public health: Why obese

people are prone to developing type 2 diabetes.

A series of studies appearing online July 26 in Nature Medicine suggest that

inflammation within the fat tissues of heavy individuals could trigger the blood

sugar disease.

What's more, each of the four completely independent studies, from two

continents and three countries, showed that interfering with these immune-cell

processes actually reversed diabetes in mice.

The long-term implications of the findings are enticing: perhaps one day a cure

for type 2 diabetes, a condition that now plagues more than 23 million people in

the United States alone.

" This group of papers suggests that cellular immunity may regulate inflammation

in fat, " said Dr. Vivian Fonseca, professor of medicine at Texas A & M Health

Science Center College of Medicine and director of the Diabetes Institute at

& White. " The authors do suggest that if you change the inflammatory

response by changing the way the body cells respond to a trigger for

inflammation, you might be able to get at the real heart of diabetes and that

suggests you could cure it. "

But Fonseca warned, all these studies were conducted in mice and have yet to be

proven in humans

In type 2 diabetes, the body often becomes resistant to insulin and doesn't use

it effectively. In the last decade or so, researchers have presented evidence

that suppressing inflammation in animals could improve insulin resistance and

other processes involved with diabetes. Inflammation is now widely believed to

be involved in many metabolic diseases afflicting obese individuals.

Inflammation in fat tissue, in particular, seems to be a culprit, by changing

fat tissue function, thereby contributing to insulin resistance.

But the exact mechanisms of the phenomenon have been unclear.

Three papers, one from Japan, one from Canada and one from the United States,

showed that immune system cells known as T cells were deficient in obese mice,

pushing the immune system to somehow initiate insulin resistance.

Restoring T cells to more normal levels actually reversed weight gain and

improved insulin resistance, even when the mice continued on a high-fat diet.

The fourth study looked at another class of immune cells called mast cells,

which are more commonly linked to allergies.

An over-abundance of mast cells contributed to obesity and diabetes in mice, but

when mast cells were removed from the system the problem was corrected,

explained study senior author Guo-Ping Shi, a biochemist with Brigham and

Women's Hospital in Boston.

" We gave mice a high-fat diet for three months and they developed obesity and

diabetes, " he said. But mice that had been stripped of mast cells did not.

" These mice are protected from the disease if they are without these cells, " Shi

said.

Shi's team also gave wild-type ( " normal " ) mice allergy medicines, which work to

" stabilize " mast cells. This also led to improvements in the mice.

" We can use the drugs to manipulate cell activity or prevent disease in this

case, " Shi said.

Shi said he has signed a contract with a local company to develop a version of

the drugs to combat diabetes in humans.