Advances in pathology of diabetes from pancreatic islets to neuropathy--a tribute to Paul Langerhans.

There emerges a world epidemic of diabetes, afflicting over 3.8 billion people globally. The socio-economic burden of this disorder is tremendous and there is an urgent need to solve the problems incurred from this disorder and to establish an efficient way of prevention and treatment. Fundamental pathology of diabetes has been too diverse to reach a simple etiology and the mechanisms of how the lesions specific to diabetes develop are yet to be clear. Nevertheless, there has been slow but significant advancement in the understanding of the disease based on characterization of the salient features of pathological lesions in human diabetic subjects. Progressive decline of islet β cells associated with increased α cell volume density was found to account for clinical manifestation of hypoinsulinemia and hyperglucagonemia in type 2 diabetes. Concurrently, signs of complications represented by distal nerve fiber loss in the skin commences from the beginning of this disease. Thus the pathological studies disclosed the major attributes in this disorder targeting the islet of pancreas and epidermal nerve, both of which were discovered by Paul Langerhans more than 140 years ago. In this review, I attempt to summarize the progress in pathology of diabetes which Langerhans opened this field.