Quantitative enzymatic histophotometry of morphologic alterations caused by urologically relevant tubular kidney damages using computed image analysis device technique.

The tissue concentration of tubular marker enzymes were evaluated in sections of kidneys from 86 patients with various underlying diseases such as hydronephrosis, interstitial nephropathies, ischemia due to renal arterial stenosis and chronic allograft rejection. In addition, as an experimental model, kidney tissue sections of 166 Wistar rats were analyzed due to hydronephrosis caused by ureteral obstruction, ischemia and obstruction of the renal vein. The tissue concentration of indicator enzymes, such as alkaline phosphatase (AP) and alanine-aminopeptidase (AAP), was considered as a parameter describing the extent of kidney tubule damage. Quantitative evaluation of enzymatic activity was performed by histophotometry using a computed image analysis device technique. As compared to normal human kidney (enzyme activity 100%), the concentrations of brush border enzymes were significantly (p less than 0.001) lower under pathological conditions (AP less than 15%, AAP less than 55%). In similar manner investigations of kidneys in animal experiments with rats exhibited lower enzyme concentrations following kidney injury caused by ureteral obstruction for 10 and 21 days (AP less than 12%, AAP less than 65%; 2p less than 0.01). Kidneys after an ischemic period of 2 h and a subsequent 14-day recirculation period displayed a significant (2p less than 0.01) decrease of normally present indicator enzyme concentrations (AP less than 22%, AAP less than 77%) as compared to normal renal organs (100%). Computed image analysis of kidney tissue sections might be a useful aid in evaluating morphologic and enzymatic patterns of human and animal kidney alterations.