Histological changes associated with ageing of the human carotid body.

A qualitative and quantitative histological study was made of the carotid bodies obtained at necropsy from 47 subjects ranging in age from 14 to 100 years. With increasing age there is a loss of more than a third of the amount of glomic tissue with a diminution in the size of the lobules. In young people the basic histological pattern of clusters, composed of cores of chief cells with surrounding rims of sustentacular cells, has commonly superimposed on it prominence of the dark variant of chief cells. In middle-aged subjects there is proliferation of sustentacular cells which appear to merge imperceptibly into fibrosis of the lobules and becomes associated with diffuse or focal infiltrates of lymphocytes.