Total collagen content and distribution is increased in human colon during advancing age.

Abstract

The effect of ageing on total collagen content of human colon has been poorly investigated. The aim of this study was to determine if ageing altered total collagen content and distribution in the human colon. Macroscopically normal ascending colon was obtained at surgery from cancer patients (n = 31) without diagnosis of diverticular disease or inflammatory bowel disease. Masson's trichrome and Picrosirius red stains were employed to identify the total collagen content and distribution within the sublayers of the colonic wall for adult (22-60 years; 6 males, 6 females) and elderly (70 - 91years; 6 males, 4 female) patients. A hydroxyproline assay evaluated the total collagen concentration for adult (30-64 years; 9 male, 6 female) and elderly (66-91 years; 8 male, 8 female) patients. Histological studies showed that the percentage mean intensity of total collagen staining in the mucosa, submucosa and muscularis externa was, respectively, 14(1.9) %, 74(3.2) % and 12(1.5) % in the adult ascending colon. Compared with the adults, the total collagen fibres content was increased in the submucosa (mean intensity; 163.1 ± 11.1 vs. 124.5 ± 7.8; P < 0.05) and muscularis externa (42.5 ± 8.0 vs. 20.6 ± 2.8; P < 0.01) of the elderly patients. There was no change in collagen content of the mucosa. The total collagen concentration was increased in the elderly by 16%. Sex-related differences were not found, and data were combined for analysis. Greater total collagen content was found in the submucosa and muscularis externa of the elderly human male and female colon. These changes may contribute to a possible loss of function with ageing.