title: The Use of Cytochrome C Oxidase Enzyme Activity and Immunohistochemistry in Defining Mitochondrial Injury in Kidney Disease.
abstract: The renal biopsy is a dynamic way of looking at renal disease, and tubular elements are an important part of this analysis. The mitochondria in 20 renal biopsies were examined by immunohistochemical (electron transport chain enzyme: cytochrome C oxidase IV [COX IV]) and enzyme histochemical methods (COX), both by light and electron microscopy. The distal convoluted tubules and thick ascending limbs showed the greatest intensity in the COX immunostains and enzyme activity in controls. The degree of mitochondrial COX protein and enzyme activity diminished as the tubules became atrophic. With proximal hypertrophic changes, there was great variation in both COX activity and protein expression. In contrast, in three cases of systemic lupus erythematosus, biopsied for high-grade proteinuria, the activity was consistently upregulated, whereas protein expression remained normal. These unexpected findings of heterogeneous upregulation in hypertrophy and the dyssynchrony of protein expression and activity may indicate mitochondrial dysregulation. Functional electron microscopy showed COX activity delineated by the intense mitochondrial staining in normal or hypertrophic proximal tubules. With atrophic changes, residual small mitochondria with diminished activity could be seen. With mitochondrial size abnormalities (enlargement and irregularity, adefovir toxicity), activity persisted. In the renal biopsy, mitochondrial analysis is feasible utilizing immunohistochemical and enzyme histochemical techniques.
authors: Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts (ZKZ)|Harvard Medical School, Boston, Massachusetts (ZKZ, SR)
authors: Zsuzsanna K
authors: ZK
authors: Zsengellér
authors: Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts (SR)|Children's Hospital Boston, Boston, Massachusetts (SR)|Harvard Medical School, Boston, Massachusetts (ZKZ, SR)
authors: Seymour
authors: S
authors: Rosen
mesh_terms: D001706:Biopsy; D003576:Electron Transport Complex IV / Q000378:metabolism*; D005355:Fibrosis; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000201:enzymology / Q000473:pathology; D007674:Kidney Diseases / Q000201:enzymology* / Q000473:pathology; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000201:enzymology*
chemical_list: D003576:Electron Transport Complex IV
keywords: adefovir nephrotoxicity; atrophy; chronic allograft nephropathy (CAN); chronic kidney disease (CKD); cytochrome C oxidase; end-stage renal disease (ESRD); enzyme histochemistry; functional electron microscopy; hypertension; hypertrophy; lupus erythematosus; megamitochondria; transplantation