Relative localization of angiotensin‐converting enzyme, chymase and angiotensin II in human coronary atherosclerotic lesions
作者:
Mitsuru Ohishi,
Makiko Ueda,
Hiromi Rakugi,
Takahiko Naruko,
Akiko Kojima,
Atsunori Okamura,
Jitsuo Higaki,
Toshio Ogihara,
期刊:
Journal of Hypertension
(OVID Available online 1999)
卷期:
Volume 17,
issue 4
页码: 547-553
ISSN:0263-6352
年代: 1999
出版商: OVID
关键词: chymase;angiotensin;human;atherosclerosis;immunocytochemistry
数据来源: OVID
摘要:
BackgroundStudies using cell cultures and animal models have indicated an important role for angiotensin II in atherosclerosis. In humans, at least two major enzymes are involved in the conversion of angiotensin I to angiotensin II: so-called angiotensin-converting enzyme (ACE) and chymase. Enhanced activation of chymase in atherosclerotic tissue homogenates has been reported in animal models, but its contribution to the generation of angiotensin II has not been studied.ObjectiveTo clarify the localization of chymase and its pathophysiologic role in the formation of angiotensin II, using human coronary arteries.Design and methodsTwenty-four coronary artery segments obtained from 14 autopsied patients were characterized histologically into the following categories: normal coronary arteries with diffuse intimal thickening, hypercellular lesions, atheromatous plaques and fibrosclerotic plaques. We compared the cellular localization of chymase, ACE and angiotensin II expression using immunocytochemical techniques.ResultsChymase was expressed only in the cytosole of mast cells in all segments. On the basis of the histologic study, the number of chymase-positive cells in the intima of atheromatous plaques was significantly higher than that in normal coronary arteries with diffuse intimal thickening. The expression of angiotensin II in the intima was enhanced in hypercellular lesions and atheromatous plaques. Localization of angiotensin II in the intima was associated with that of ACE. Immunodouble staining did not show colocalization of angiotensin II and chymase.ConclusionsThese results suggest an important role for the production of angiotensin II by ACE in the progression of atherosclerosis in human coronary arteries. Enhanced expression of chymase appears not to be involved in angiotensin II production in the intima.
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