DISTRIBUTION OF ENDOTHELIN IMMUNOREACTIVITY IN HUMAN KIDNEY CORRELATES WITH ANTEMORTEM ACUTE-RENAL-FAILURE - A POSSIBLE POSTMORTEM IMMUNOHISTOCHEMICAL TEST

The role of endothelin in the normal kidney function, as well as in di sease states, has been studied in animal models. In addition, it was s hown previously that endothelial, mesangial, and epithelial components of the nephron produce endothelins, in particular ET-1. We performed immunohistochemistry for ET-1 reactivity on 31 autopsy and four surgic ally removed kidneys. Eighteen cases had clinical diagnoses of acute r enal failure (ARF) In the remaining 17 cases with normal or unchanged renal function before death or surgery, ET-I immunoreactivity was pres ent in tubular epithelium, with the most intense staining in the medul lary collecting tubules. In 13 of 18 cases of ARF, tubular staining wa s either replaced or accompanied by interstitial reactivity in the inn er and outer medulla, corresponding to the location of the vasa recta and interlobular arteries identified by factor VIII immunostaining. Co ntrolled autolysis performed on normal kidney over 72 hours postmortem produced tubular epithelial degradation with reduced epithelial cell endothelin reactivity, but not an interstitial pattern. In situ hybrid ization for ET mRNA localized expression to tubular and collecting duc t epithelium in both normal and acute renal failure cases. The change in the localization of ET-1 immunoreactivity from tubular epithelium t o the interstitium in these ARF cases does not appear to be the result of increased vascular endothelial production of endothelin. This alte red immunoreactivity pattern for ET-1 may be a marker of antemortem tu bular damage and can be used as an adjunct in the autopsy diagnosis of ARF. Copyright (C) 1997 by W.B. Saunders Company.