The incidence of occurrence and the pathogenesis of renal lesions in diabetes mellitus were studied by means of proteinuria, renal function tests and kidney biopsies, and how the treatment of diabetes would affect the development of renal lesions was investigated. Also some observations on the clinical and histopathological findings about the group of Kimmelstiel-Wilson's syndrome were made.
1) About 30% of diabetics had glomerular dysfunction. This percentage increased for the young and elderly diabetics whose duration of diabetes were more than 5 years. Glomerular dysfunction did not seem to be related to the severity of diabetes but had some relation to the abnormal fat metabolism. Some diabetics with glomerular dysfunction showed increase of 17-ketosteroid in urine als the function of adrenal cortex.
2) Tubular dysfunction was observed more in longstanding elderly diabetics with glomerular dysfunction and seemed to be closely related to the severity of diabetes, especially such tendency was marked for young patients without glomerular dysfunction.
3) The Histological changes of glomeruli among the diabetics were mostly proliferation of mesangium that seemed to be features in early stage of renal lesions because such changes were observed since young generation and increased with duration of diabetes. The author assumes that glomerular nodule were caused by proloferation of Mesangium. Most of diabetics revealed tubular epithelial degeneration and sclerotic change of kidney blood vessels.
4) Specific lesions associated with diabetes were nodular formation of glomeruli (Kimmelstiel-Wilson's syndrome) that were observed in elderly group, especially among longstanding diabetics. The group with this nodular lesions were characterized by proteinuria which was most popular, hypertension, diabetic retinopathy and edema, but one has to be cautious of diagnosing them only from such clinical findings. The author suggested to call renal lesions with such clinical findings clinically; “diabetic nephropathy”. Any specific result of renal function tests in diabetics with this nodular lesions was not observed.
5) Renal functions were kept in superior condition for the diabetics whose metabolism were well-controlled from the early stage of diabetes than those who did not have the treatment and the difference between two groups became bigger as the duration were prolonged. Therefore in order to prevent the development of renal lesions, it is very important to control the carbohydrate metabolism since early stage, besides to keep the fat and protein metabolism normal.
