INS and type 2 diabetes mellitus: Although it has long been accepted that insulin resistance is the leading factor in the pathogenesis of type 2 diabetes (3, 4), accumulating evidences over the past decades have showed that defects in pancreatic β-cell function is also one of major pathophysiologic abnormalities underlie most cases of T2DM (5-7). Pancreatic β-cell injury led to insufficient insulin supply that decreased sensitivity of the body tissues to respond to insulin (5-7).