AGE-RELATED CHANGES IN THE HISTOMORPHOLOGY OF THE HUMAN VESICAL TRIGONE
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Background: The histology of the human vesical trigone (VT) comprises the mucosa, muscularis layer and adventitia. Their structural alterations, as a result of aging, may predispose individuals to vesical ureteric reflux (VUR) of urine, retrograde ejaculation and incontinence. Despite this, histomorphological changes at the VT following aging in humans remains to be fully elucidated. 

Objective:To describe age-related changes in the histomorphology of the human vesical trigone. 

Study design:A descriptive cross-sectional study. 

Materials and Methods:Twenty eight (28) specimen of the bladder trigone were obtained from autopsies at the Chiromo Funeral Parlor and Kenyatta National Hospital. They were categorized into different age groups; < 20, 21-30, 31-40, 41-50, 51-60, > 60. Histological sections were then obtained from the VT mid-section for paraffin-embedded sectioning and staining. Hematoxylin and Eosin stain was used to demonstrate the general tissue architecture, Masons’ Trichrome for collagen fibers and Weigert’s for elastic tissue. Description of the general organization of the VT followed by morphometry of the observed changes was done for the different age groups. 

Data management:Morphometric data were expressed in means and standard deviations in different age groups. Data are presented in tables and graphs. Histomorphological findings were presented using photomicrographs. 

Results:Stratified squamous epithelium was found commonly among the elderly while transitional epithelium was common in individuals below forty (40) years. The VT epithelia and muscular layer appeared to increase in thickness in the first four decades of life, however beyond forty years (40), both layers gradually decreased. Additionally, there was a progressive increase in collagen fiber density and a decrease in elastic tissue density within the muscularis layer with aging.

Conclusion:The present study suggests that aging has an effect on the mucosal and muscular anatomy of the vesical trigone (VT). The high prevalence of stratified squamous epithelium at the VT, confirms it as a normal variant and therefore this metaplasia should not always be considered as precancerous but as a normal age-related change. Additionally, the decrease in muscle and epithelial thicknesses and fibrosis, seen in the elderly, might be contributing factors to the higher incidence of incontinence, vesico-ureteric reflux of urine and increased frequency of micturition in this population.