Neovascularization at the vascular pole region in diabetic glomerulopathy

Background. Diabetic nephropathy is associated with renal structural change s involving ail of the compartments. Most characteristic is the diabetic gl omerulopathy. Studies of the histological changes during the early phases o f nephropathy have included the glomerulopathy and also the juxtaglomerular structures. Neovascularization, well-known in diabetic retinopathy, has al so been observed in the kidney. The present study concerns estimates of fre quency of neovascularization at the vascular pole region in early stages of diabetic nephropathy. Methods. Extra efferent arterioles at the glomerular vascular pole were det ected during measurements of the vascular pole area applying 1-mu m serial sections through kidney biopsies. It was observed that more than one effere nt arteriole existed occasionally. The present study was carried out with t he aim of estimating the frequency of this phenomenon in diabetic patients and in non-diabetic controls, the diabetic patients categorized according t o the level of albumin excretion rate. Results. Neovascularization was first observed in IDDM patients with microa lbuminuria. Some of the cases presented the phenomenon in all of the glomer uli studied. As the examinations of many kidney biopsies continued the phen omenon was observed also in the non-diabetic control group and in one IDDM patient with normoalbuminuria. However, the frequency was statistically hig hly significantly increased in patients with elevated albumin-excretion. Wi thin this group a strong correlation between frequency of neovascularizatio n and the severity of diabetic glomerulopathy is seen. Conclusions. The vascular abnormality localized to the vascular pole region is observed occasionally in the normal kidney, but the frequency is increa sed in patients with diabetic glomerulopathy. The abnormality may develop a s a consequence of a long-standing diabetic glomerulopathy and might lead t o less pronounced elevation of albumin excretion.