Human rectal endocrine cells and aging.

Endocrine cells of the human rectum were investigated by immunocytochemistry and quantified by computerized image analysis in three different age groups. The age intervals were 20-29, 40-49 and 60-69 years. No statistically significant differences were found between the age groups, regarding the numbers of all endocrine cell types investigated, namely peptide YY (PYY)-, pancreatic polypeptide (PP)-, enteroglucagon-, somatostatin- and serotonin-immunoreactive cells. Nor was there any difference regarding the cell secretory index. Nuclear volume was significantly greater in the 40-49 year olds than the other age groups. There was no statistically significant difference between females and males regarding numbers of the endocrine cell types investigated. It is concluded that age does not affect the endocrine cells of the human large intestine as it was earlier found in animal models of aging. It is imperative that caution should be taken when applying results obtained in animal models of aging in humans.