A histomorphometric method for evaluating topographic differences in degree of early atherosclerosis within the human aorta

The aim of the study was to develop an unbiased topographically oriented method of evaluating early atherosclerotic lesions in the aorta and to apply this to a series of human aortas from young adults. A systematic sampling procedure and histomorphometric analysis of intimal thickening is described. Results from a group of 15 young adults (aged 18-40 years) showed a characteristic pattern with increasing intimal thickening when moving distally from the thoracic to the upper and finally to the lower abdominal aorta, but also a shift in the localization of the most pronounced intimal thickening from the posterior to the anterior and back to the posterior aspect. This pattern was found in aortas both with minimal and with more pronounced atherosclerosis, and supports the view that the early intimal thickening precedes the atherosclerotic lesions and marks the sites of predilection for the more advanced disease processes. An increase in intimal thickness with age could be demonstrated in the aortas without overt atherosclerosis. The simple sampling procedure, well-defined sampling sites, and ability to demonstrate and quantitate differences in intimal thickening and plaque morphology make this method well suited for relating morphometric data to other parameters of interest when studying the etiology and dynamics of atherosclerotic disease.