MORPHOMETRIC STUDY SHOWING THE IMPORTANCE OF DISTAL TUBULAR DAMAGE INIMPAIRED CREATININE CLEARANCE

It is established that the glomerular filtration rate (GFR) is affecte d by tubulointerstitial lesions (TIL) in various glomerulonephritides. The fall in GFR is believed to be the result of damage to tubules, ma inly the proximal tubules, and interstitial widening. We performed the morphometric point-counting study in 45 renal biopsies with various g lomerular diseases, and 10 controls, to quantify interstitial widening , proximal and distal tubular damage, and to study their relation to s erum creatinine clearance, and also to determine the best predictor, a nd the degree of damage in each component of the tubulointerstitium. T here was a statistically significant correlation of serum creatinine c learance to interstitial widening (r = -0.748; p = 0.0001) and decreas e in proximal (r = 0.611; p = 0.0001) and distal tubular area percenta ges, with a maximum value of the correlation coefficient for the dista l tubules (r = 0.818; p = 0.0001). On the basis of relative mean diffe rence values, it appeared that in the presence of tubulointerstitial d amage, the distal tubule sustained greater damage. Therefore, distal t ubular damage may serve as an important prognostic parameter.