Enzyme content of casts in chronic renal disease.

An investigation of enzyme content of diseased human kidneys was carried out. A broad spectrum of enzymes was studied histochemically in these kidneys. A surprising finding of the presence of various lysosomal, microsomal, and nuclease enzymes was demonstrated in epithelial casts in the kidneys. In contrast, mitochondrial enzymes were not present in the epithelial casts. This study has demonstrated that epithelial casts still retain certain enzymatic activities and are not enzymatically inert. Recently, we subjected portions of kidneys removed from patients with chronic renal disease (chronic pyelonephritis and chronic glomerulonephritis) prior to transplantation to a comprehensive enzyme histochemical analysis. We observed marked differences in the enzyme content of intratubular epithelial casts.