Relationship of renal histological damage to glomerular hypertension in patients with immunoglobulin A nephropathy

Objective Studies of experimental animals show glomerular hypertension to b e important in the progression of glomerular disease. We evaluated this con nection clinically by examining the relationship between glomerular hemodyn amics and histological changes in patients with immunoglobulin (Ig)A nephro pathy. Methods The subjects were 23 patients with IgA nephropathy. All patients un derwent renal biopsies. Glomerular hemodynamics, in terms of glomerular cap illary hydraulic pressure (PGC) and the whole-kidney ultrafiltration coeffi cient, were calculated from the renal clearance, plasma total protein conce ntration, and pressure-natriuresis relationship. The severity of glomerulos clerosis, tubulointerstitial damage and mesangial matrix expansion was eval uated semiquantitatively. Results PGC ranged from 33-69 mm Hg, and the mean arterial pressure (MAP) f rom 79-112 mm Hg. Their correlation was not significant (r = 0.29, P = 0.18 ), PGC was significantly correlated with the glomerulosclerosis score, and also with the score for tubulointerstitial damage (r = 0.65, P < 0.001 and r(s) = 0.59, P = 0.007, respectively), but not with the score for mesangial matrix expansion (r = 0.08, P = 0.72). MAP was significantly correlated on ly with the score for tubulointerstitial damage (r(s) = 0.63, P = 0.004). I n multiple linear regression analysis of the histological changes and hemod ynamics, the glomerulosclerosis score and the score for tubulointerstitial damage were correlated with PGC, but not with MAP. Conclusion These clinical results support the speculation that glomerular h ypertension is involved in the glomerulosclerosis and tubulointerstitial da mage that occurs in IgA nephropathy. J Hypertens 2000, 18:103-109 (C) Lippi ncott Williams & Wilkins.