QUANTITATIVE-ANALYSIS OF INFLAMMATORY CELLS IN AORTIC ATHEROSCLEROSISOF YOUNG-ADULTS

Cellular analysis of aortic atherosclerotic lesions has been pursued e xtensively in recent years, although most of these investigations have involved the detection of inflammatory cells in chronically diseased tissue or artificially induced atherosclerosis in an animal model. Few studies have attempted to quantify accurately, using computer analysi s systems, the degree of cellular infiltration in a statistically sign ificant number of samples, in tissue from young adults. In this study, segments of human aortae were collected at autopsy from 29 individual s ranging in age from 15 to 35 years. The tissue was embedded in paraf fin and stained using routine histological and automated immunohistoch emical staining techniques. The sections were evaluated using advanced image analysis techniques to investigate the differences in cellular composition and cell activation between the dorsal and ventral aspects of the human aorta and to correlate these findings to the age of the subjects. These regions have been previously shown to have a high (dor sal) and low (ventral) probability of developing sudanophilic lesions. Our data demonstrated that statistically different cell populations e xist in the dorsal and ventral regions of each vessel. The dorsal aspe ct (i.e., high-probability region) had a greater number of HAM56(+)(36 .9% increase, p = 0.0002) and HLA-DR alpha(+) cells (44.2% increase, p = 0.0035) than did the ventral surface (i.e., low-probability region) , although there were no significant differences in the number of CD43 (+) lymphocytes. When grouped according to age, results showed signifi cant increases in the dorsal region when considering HAM56(+) and HLA- DR alpha(+) cells (p = 0.033 and 0.046, respectively). Morphologically , a greater number of foam cell aggregates were found to occur in the dorsal region of the vessel than in the ventral portion. Our results i ndicate that the microarchitecture and cellular composition of the dor sal and ventral aorta are significantly different, with these variatio ns becoming more marked with age.