Insulin-producing cells found in a variety of tissues in diabetes

Cells that produce insulin have been unexpectedly found in the fat, liver and bone marrow of diabetic mice, said researchers at Baylor College of Medicine (BCM) in a report that appeared today in the Proceedings of the National Academy of Sciences.

“In fact, the appearance of insulin-producing cells occurs in both type 1 (juvenile) and type 2 (adult-onset) diabetic mice,” said Dr. Lawrence Chan, chief of the BCM endocrinology section and professor in the department of medicine and molecular and cellular biology.

“The common denominator in all the animals is high blood sugar, not insulin-deficiency,” he said. “High blood sugar causes these cells to produce insulin.”

The numbers of cells and the amount of insulin produced are both very small and do not seem to ameliorate the animals’ disease, said Chan.

He found that the source of the insulin-producing cells is the bone marrow, which had been identified as the origin of many different kinds of tissues in recent years. He and his colleagues were surprised that only a brief three-day period of high blood glucose was sufficient to nudge the cells outside the pancreas to produce insulin.

If this inherent property of cells can be harnessed and augmented, Chan speculates, scientists could it to generate insulin-producing cells from other tissues for the treatment of diabetes. If the production of insulin by cells outside the pancreas affects the immune system, which goes awry in people predisposed to type 1 diabetes, it could affect the course of the disease.