Renal histopathology in US African-Americans with presumed hypertensive nephrosclerosis

African-Americans have, in comparison with Caucasians, excess hypertension and end-stage renal disease, which has been presumed to be due to hypertens ion. However, systematic renal biopsy assessment of lesions in this populat ion and verification of this clinical impression have not been done. During the pilot phase of the AASK trial, 46 hypertensive (diastolic BP > 95 mmHg ) non-diabetic African-American patients between the ages of 18-70 years, w ith glomerular filtration rate (GFR) between 25 and 70 mL/min per 1.73m(2) and without marked proteinuria were therefore biopsied to assess underlying lesions. Adequate biopsy material was obtained in 39 (29 men and 10 women) , on average 53.0 +/- 11.0 years old, with MAP of 109 +/- 15 mmHg and GFR 5 1.7 +/- 13.6 mL/min per 1.73 m(2). Of these 39 biopsies, 38 showed arterios clerosis and/or arteriolosclerosis, severity on average 1.5 +/- 0.9 and 1.5 +/- 0.8, respectively, on a 0-3+ scale. Interstitial fibrosis was moderate , 1.3 +/- 0.9 (0-3+ scale). Segmental glomerulosclerosis was present in fiv e biopsies, and in one patient, biopsy and clinical findings were consisten t with idiopathic focal segmental glomerulosclerosis. Additional lesions in cluded mesangiopathic glomerulonephritis in one patient, basement membrane thickening suggestive of diabetic nephropathy in one, and cholesterol embol i in two cases. Arteriolar and arterial sclerosis were tightly linked, and correlated with interstitial fibrosis and the reciprocal of serum creatinin e. Global glomerulosclerosis was extensive, involving on average 43 +/- 26% of glomeruli. The extent of this lesion did not correlate with degree of a rteriolar or arterial thickening, but did correlate with systolic blood pre ssure (P = 0.0174), the reciprocal of serum creatinine (P = 0.0009), serum cholesterol (P = 0.0129) and interstitial fibrosis (P < 0.0001). These data underscore that the clinical diagnosis of hypertensive nephrosclerosis bas ed on strict clinical criteria in non-diabetic African-Americans with mild to moderate renal insufficiency without marked proteinuria is strongly corr elated with renal biopsy vascular lesions consistent with this clinical dia gnosis. However, the mechanism(s) for this clinicopathologic constellation remains undetermined. Current studies are focused on possible genetic contr ibutions to the development of hypertension and renal lesions in this popul ation.