The Cell Populations and other Components of the Atheromatous Lesions in Young People — A Preliminary Report —

Atherosclerosis is a chronic disease process which develops over a period of many years in most individuals who are at risk in the more highly developed industrialized countries of the world. In general there is a much better understanding of the advanced lesions which lead to clinical disease as compared to knowledge about the factors influencing developing plaques in young people at the cellular and chemical artery wall level. In the USA a fourteen-center cooperative research program is aimed at learning more about how several risk factors lead to progression of the atherosclerotic plaque by utilizing pathobiological methods which can be applied to autopsy samples of arteries and other tissues. This program [1–3], which is called the Pathobiological Determinants of Atherosclerosis in Youth (PDAY), has now collected carefully standardized artery samples from over 1500 young people. These anatomically standardized samples of aortas and coronary arteries are obtained at nine forensic collection centers and come from autopsies of individuals aged 15 through 34 who are free of chronic disease and who have succumbed suddenly and unexpectedly, usually of traumatic causes. These nine collection centers are following a very detailed protocol and manual of procedures in order to insure that the artery samples and the other samples utilized for risk factor assessment from these autopsy cases meet the requested criteria and that they are preserved, processed, and distributed to the various study centers under as near ideal conditions as possible. As is shown in Figure 1, the sampling of the aorta and the left anterior descending coronary artery (LAD) for the core studies and for special studies is performed in a carefully planned way so that “lesion prone” and “lesion resistant” areas, as previously determined by Cornhill et al. [4], can be compared in each microscopic section that is studied. Furthermore, these core samples are processed and prepared for micromorphometry in a way that makes it possible to study the localization of lipid by means of oil red-O (ORO) staining in a section that is very close to a paraffin imbedded section which is stained for smooth muscle cells, specific mononuclear inflammatory cells, selected apolipoproteins, and connective tissue elements [5]. Open image in new window Figure 1 This figure illustrates in diagrammatic form some of the strengths and advantages of the core sampling strategy which PDAY is employing on all of its cases. As can be seen, these samples make it possible to study and to evaluate quantitatively the thoracic aorta core sample area (# 1) as compared to the standard abdominal aorta areas (# 16 and # 18). It also makes it possible to evaluate similarly the left anterior descending coronary artery (LAD) standard samples (# 44 and # 45) and to compare “lesion prone” and “lesion resistant” areas in each of these standard samples. The arteries are oriented and marked so that under the microscope it is relatively easy to distinguish “lesion prone” and “lesion resistant” areas and to match up the sections stained for lipid with the sections stained for connective tissue components. These are less than a millimeter from each other because of the way samples are prepared for microscopic examination. (As modified from Wissler, R.W. et al. [1])