In type 1 diabetes, the body relentlessly attacks and destroys its own insulin-producing pancreatic beta cells. But a study by Joslin Diabetes Center scientists now has firmly established that some of these cells endure for many decades in a small group of people with the disease—offering clues to potential treatments for preserving and even restoring the crucial cell population.
Joslin has been awarding 50-Year Medals to people with insulin-dependent diabetes since 1972. The finding comes from the Joslin 50-Year Medalist Study, which examines this select cohort to discover protective factors for their long-term survival.
Published online by Diabetes this week, the research analyzed pancreatic function in 411 Medalists and examined nine pancreases from Medalist organ donors.
Blood samples showed that many in this group exhibit C-peptide molecules (a marker of insulin production), blood glucose levels that rise less after a meal than would be expected in the absence of insulin, and signs of autoimmune attack.
Moreover, all of the donated pancreases displayed active insulin-producing beta cells, with some of the cells scattered individually and others clumped with different kinds of hormone-producing cells in the normal pancreatic structures called islets. Most strikingly, some of the beta cells showed signs of cell proliferation, cell death and autoimmune attack.
"We've clearly demonstrated that functional beta cells are still in the pancreas," says Hillary Keenan, Ph.D., Joslin research associate and first author on the paper.