Metaplasia of the parietal layer of Bowman's capsule in the human kidney. Incidence in alcoholic liver disease and hypertension

Abstract

This report is the second of two surveys to determine the incidence of metaplasia of Bowman's parietal epithelium in the human kidney. Human kidney sections obtained at autopsy at the Department of Pathology, University of Texas Medical Branch, Galveston, Texas, were examined with the light microscope. The kidneys were fixed in neutral formalin, sectioned at 6 pm and stained with hematoxylin and eosin. Autopsy records were consulted after kidney section examination to determine if there was any correlation between clinical disease, histopathological changes in organ systems and metaplasia of Bowman's capsule. The kidney sections represented both sexes in 8 age groups, from less than one year to 80 years. A total of 174 kidneys, representing 174 individuals, were evaluated. One hundred renal corpuscles were counted per section and the parietal layer of Bowman's capsule was classified as normal (squamous) or metaplastic (cuboidal). Of the 174 kidneys examined, 137 (79% )- 79 male and 58 female - had metaplasia of Bowman's capsule. On the average, in the kidneys with the lesion, 6% of the renal corpuscles had metaplasia of Bowman's parietal layer. The lesion was present in both sexes in all age groups. The autopsy records revealed that metaplasia of Bowman's parietal epithelium was usually present with hepatic fatty changes andlor congestion. Alcoholic liver disease and hypertension represented the most frequent clinical diseases in the sample; these conditions had the highest incidence of metaplasia. Twenty-six of the 174 kidney samples were from individuals with alcoholic liver disease, all of whom had metaplasia of Bowman's capsule. In the latter kidneys the mean percentage of glomerular capsules with metaplasia was 14%, with a range of l to 46%. Thirtyeight of the 174 kidney samples were from individuals with hypertension, 29 (76% ) of whom had metaplasia of Bowman's capsule. In these kidneys the mean percentage of glomerular capsules with metaplasia was 6% with a range of 1 to 16%. These observations suggest that metaplasia of Bowman's parietal epithelium is a common occurrence in the human kidney under different pathological conditions, and is especially prominent in alcoholic liver disease and hypertension.