For a long time, doctors thought that the onset of type 1 destroyed all beta cells. But recent research coming out of Joslin is suggesting a different story.
Susan Bonner-Weir, PhD, Senior Investigator in Islet Cell and Regenerative Biology at Joslin and Professor of Medicine at Harvard Medical School is working on understanding how beta cells can still exist after years of type 1 diabetes.
The Joslin Medalist program honors people who have had type 1 diabetes for at least fifty years. Many of the honorees choose to participate in studies being conducted at Joslin that examine their lifestyles and genetic codes for clues to what keeps them living well with this disease for more than five decades. In one branch of this research, Dr. Bonner-Weir studies the pancreases of Medalists who have passed away and donated their organs to furthering diabetes research.
“The thing that is quite striking is, I’ve look at over 50 pancreases and every single one of them has some beta cells,” says Dr. Bonner-Weir. “These people had an average of 65 years with type 1 diabetes, but they still have beta cells.”
The most peculiar finding, though, is that these beta cells aren’t necessarily found within an islet. They instead crop up here and there throughout the pancreas. It appears that the pancreas can recognize that its ability to create insulin is being hampered by the autoimmune attack and can generate insulin-producing cells in new areas that are as-yet untouched by the autoimmune response.
According to Dr. Bonner-Weir, this pattern of beta cell regrowth probably means beta cell destruction isn’t a one-time occurrence. It appears that the body struggles to restore beta cell function while being repeatedly attacked by the autoimmune system.. “My interpretation is that you’re having a slow but continued regrowth of the beta cells, but the immune system is being activated again and kills off the new beta cells so that you’re only having a few lasting at any one time. You’re not accumulating them as you might if you didn’t have the autoimmunity,” she said.
Because of the ever-present autoimmune attack these beta cells can’t get enough traction to produce the amount of insulin the body needs, but knowing about this back and forth between beta cells and autoimmunity can open a new avenue of treatment in type 1 diabetes.
“If we understand that yes, you can have a significant amount of regrowth [of beta cells] in an adult human pancreas, the question becomes can you then get this process to build up enough [beta cells] to accumulate if you block the autoimmunity?” asks Dr. Bonner-Weir. She says that since it takes several years after diagnosis for most beta cells to be destroyed, there is a window of time even after diagnosis for this treatment to work. Doctors would need to first end the autoimmune attack, then stimulate the beta cell regeneration process. But if successful, they could reduce the requirement for injected insulin, or even completely remove the need for diabetes medication.