Remodeling of the innervation of pancreatic islets accompanies insulitis preceding onset of diabetes in the NOD mouse

The innervation of the islets of Langerhans may constitute a first target for the autoimmunity that develops in type 1 diabetes. Here, we report the occurrence of a decrease in general innervation within the islets in the nonobese diabetic (NOD) mouse, and the establishment of strands of Schwann cells, as detected via p75 and S-100 immunoreactivity (IR), and varicose nerve fibers expressing tyrosine kinase A (TrkA) in association with the immune cells. The findings suggest that there are marked attempts for neurotrophins to promote nerve ingrowth and survival for islet tissue and that remodeling of innervation occurs in the continuation of the insulitis process preceding the onset of type 1 diabetes.