Sex differences in histomorphology of the human carotid body

Abstract

Knowledge of sex differences in the histomorphology of the carotid body is important in understanding observed differences in respiratory function and disorders. There are few studies on sex differences in the carotid body. This study therefore aimed at describing these differences in the histomorphology features of the human carotid body. Thirty six random carotid bodies from cardiovascular disease free individuals (20 male, 16 female) obtained during autopsy at the Department of Human Anatomy, University of Nairobi were studied. Specimens obtained within 48 hours of death were fixed in 10% formaldehyde solution and processed routinely for paraffin embedding. Seven micron thick serial sections were stained with H&E, Mason’s trichrome and examined with light microscope. Stereology was done to determine area occupied by parenchyma, stroma and vasculature. Data were analyzed using SPSS version 13.0. The student’s t test was used to compare sex differences. The data are represented using tables and macrographs. The human carotid body is highly cellular with two varieties of cells namely; chief and sustentacular. It is heavily vascularised and densely innervated. Females showed higher concentration of chief cells, more profuse vascularization and denser innervation when compared with their aged matched male counterparts. The aging changes characterized by fibrosis, cellular degeneration vascular and neural attenuation are less severe in females. Sex histomorphological differences in the human carotid body characterized by higher population of chief cells, density of vascularity, innervation and blunted age related morphological attenuation underpin differences in its function and disease.