PARK7 and type 2 diabetes mellitus: DJ-1 expression in pancreatic islets is up-regulated by hyperglycemia, increases in human islets with an increasing age of the donor, is decreased in human T2DM islets, and helps to protect the integrity and function of islet mitochondria from oxidative stress possibly ensuring physiologic glucose-stimulated insulin secretion during aging and under conditions of insulin resistance [10, 11].