PROLIFERATING CELL NUCLEAR ANTIGEN EXPRESSION IS INCREASED IN SMALL-BOWEL EPITHELIUM IN THE ELDERLY

Although previous studies suggest that in aging animals the small inte stine is in a hyperproliferative state, no information is currently av ailable on the influence of age on the proliferation pattern of human small bowel enterocytes. The immunohistochemical expression of the pro liferating cell nuclear antigen (PCNA), the villous height to total mu cosal thickness ratio and the enterocyte height were evaluated in a pa nel of duodenal biopsy specimens obtained from 18 subjects aged less a nd 14 subjects aged more than 65 years. There was a significant positi ve correlation (P < 0.001) between age in years and percent of positiv e PCNA enterocytes both at the level of crypts (r(s) = 0.50) and villi (r(s) = 0.77). Moreover, the percentage of PCNA(+) enterocytes was si gnificantly higher in elderly versus adult subjects, both at the level of villi (6.5 vs 0%; P < 0.001) and of crypts (40.0 vs 23.7%; P < 0.0 1). No correlation was found between the percentage of PCNA + enterocy tes and enterocyte height or villous height to total mucosal thickness ratio. Our results show that PCNA reactivity increases with advancing age both in crypts and villi. This abnormality of the proliferation p attern may explain the coexistence of normal morphology and impaired a bsorptive function in the elderly. (C) 1998 Elsevier Science Ireland L td. All rights reserved.