Search for Cause of Type 2 Diabetes Continues

Scientists looking through the maze of possible links between obesity and the development of type 2 diabetes have hit another wall. Type 2 diabetes is characterized by insulin resistance. Researchers hope that by pinpointing the reason why an increase in body fat increases insulin resistance, the treatment and prevention of type 2 diabetes will be easier. After the discovery that the recently identified hormone resistin is not related to insulin resistance in humans, the root of this disease continues to elude researchers.

Recent research shows that resistin increases insulin resistance in rats. When rats gain fat cells, expression of the resistin gene goes up, sending higher levels of the hormone into their blood streams. The fatter the rats, the higher their levels of resistin. This same research shows that the higher the rats’ levels of resistin, the more severe their insulin resistance. One hope of researchers is that by linking a hormone to insulin resistance, medications can be developed to interfere with the actions of the hormone and stop insulin resistance in patients.

Scientists tried to duplicate these promising results in humans. Although rats and humans share many metabolic similarities, the expression of resistin is not one of them.

A team of researchers led by Jürgen Janke and Stefan Engall in Berlin, Germany studied fat cells collected from 24 women undergoing plastic surgery. They found no link between resistin hormone level and insulin sensitivity in the women. There was also no link between body weight and level of resistin. The researchers found that human fat cells express resistin in such low levels, they are barely detectable.

Type 2 diabetes has reached epidemic levels in the United States and other industrialized societies, and continues to rise. Because it is linked strongly with the rise in obesity, prevention efforts are one and the same: healthier eating and physical activity habits. While public health efforts are underway to help Americans move more and eat better, scientists are busy working to find the path that will lead to the cause of the disease, and possibly new treatment and prevention options.

The full report appears in the January 28, 2002 Obesity Research. s