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Intimal neovascularization in human coronary atherosclerosis: its origin and pathophysiological significance
M Kumamoto1, Y Nakashima, K Sueishi
1First Department of Pathology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Insights
Newly formed blood vessels in human coronary arteries primarily originate from the adventitia, not the lumen. This intimal neovascularization correlates with coronary artery stenosis and inflammation.
Area of Science:
- Cardiovascular Pathology
- Histopathology
- Angiogenesis
Background:
- Atherosclerosis involves complex changes in the coronary intima.
- Neovascularization within atherosclerotic lesions is a poorly understood phenomenon.
- Understanding vessel origin is crucial for comprehending lesion progression.
Purpose of the Study:
- To investigate the histopathological characteristics of new vessels in atherosclerotic coronary intima.
- To determine the origin and correlation of intimal neovascularization with lesion severity.
Main Methods:
- Postmortem angiography and stereoscopic examination of 31 human coronary arteries.
- Light microscopy of 25 anterior descending coronary arteries using serial sections.
- Morphometric analysis of histological alterations and neovascularization.
Main Results:
- Intimal neovascularization density positively correlated with luminal stenosis, inflammation, granulation tissue, and atheromatous changes.
- Vascular density decreased in hyalinized and calcified intima.
- Newly formed vessels originated mainly from adventitial vasa vasorum (28x more frequent than luminal origin).
- Adventitial vessel origin increased with stenosis severity; luminal origin associated with hemorrhage.
- Luminal-origin vessels were most frequent with 40-50% stenosis.
Conclusions:
- Intimal neovascularization in coronary arteries predominantly arises from the adventitia.
- Neovascularization is closely linked to the degree of coronary stenosis and inflammatory processes.
- Adventitial neovascularization is a significant feature of advanced atherosclerotic lesions.
Abstract:
To investigate the histopathological characteristics of the newly formed vessels in the atherosclerotic intima of human coronary arteries, we conducted postmortem angiography in 31 cases, including 11 with myocardial infarction. Vessels were examined three-dimensionally under the stereoscope. In addition, we evaluated 25 anterior descending coronary arteries unrelated to the occurrence of myocardial infarction by light microscopy using 3-mm stepwise sections and 5-microns serial sections. Histological alterations were analyzed morphometrically to determine the correlation between the degree of intimal neovascularization and the growth of the endothelium into the atherosclerotic intima from the adventitia or lumen. There was a significant positive correlation between the density of new vessels in the intima and the incidence of luminal stenosis, the extent of chronic inflammatory infiltrate, the formation of granulation tissue, or the atheromatous changes, whereas the vascular density decreased in the extensively hyalinized and calcified intima. The newly formed intimal vessels originated mainly from the adventitial vasa vasorum and also partly from the proper coronary lumen. The intimal vessels that originated from the adventitia occurred approximately 28 times more frequently than those that originated from the luminal side. The frequency of former vessels increased as the luminal stenosis became more severe, whereas the latter vessels were found most frequently in the presence of 40% and 50% stenosis. Vessels originating from the proper lumen were more often associated with fresh or old hemorrhage. We conclude that intimal neovascularization largely originates from the adventitia and is closely associated with the extent of coronary stenosis and the histological inflammatory reaction.