Using an experimental DNA-based therapy, scientists might slow the self-destructive immune reaction against insulin-making cells that causes type 1 diabetes. The finding, appearing in the June 26 Science Translational Medicine, represents a promising but preliminary advance toward devising a treatment for the condition, which often strikes in childhood.
Lawrence Steinman of Stanford University and his colleagues injected 26 volunteers weekly with placebos. Another 54 got the experimental treatment, which is designed to dampen the body’s immune reaction against insulin-making beta cells in the pancreas. In diabetes patients, rogue CD8 T cells attack a protein on beta cells called proinsulin, a precursor compound that becomes insulin after modification. The attack sabotages beta cells and insulin production.
The experimental treatment contains replacement DNA for the gene encoding proinsulin. Patients who received the DNA for 12 weeks apparently made altered proinsulin proteins that signal the immune system to rein in the rogue T cells. After five months, levels of the T cells declined in treated patients. The patients also showed stabilization and even improvement in measures of insulin production after 12 weeks, suggesting that the therapy might arrest beta cell destruction, the authors say. But both changes didn’t last long after treatment ended.
