Deposition of oxidized low-density lipoprotein and collagenosis occur coincidentally in human coronary stenosis: an immunohistochemical study of atherectomy

Background Coronary stenosis involves lipid accumulation, fibrosis and cell proliferation. Objective To clarify the role of oxidized low-density lipoprotein (LDL) in coronary stenosis by examining atherectomized coronary lesions from patient s with primary stenosis and restenosis after percutaneous transluminal coro nary angioplasty (PTCA). Methods Atherectomized coronary tissue from 28 patients with primary stenos is and restenosis at 4.3 +/- 1.0 months after PTCA were examined using morp hometrical and immunohistochemical techniques. Results Serum lipids in all of the patients were within the normal range an d no differences were noted between the two groups. There were no differenc es in the mean cross-sectional areas of whole specimens obtained from each group, and sclerotic lesions with atheroma or calcification were found to a similar extent in both groups. However, the restenosis group had a signifi cantly greater area (6-fold) of immature smooth-muscle-rich lesions than th e primary stenosis group, although there was no difference in lipid-laden f oam-cell containing lesions. in foam-cell-containing lesions, apolipoprotei n B was accumulated extracellularly, while oxidized LDL was primarily depos ited intracellularly in lipid-laden foam cells. However, no deposition of a polipoprotein B, oxidized LDL or lipids was noted in smooth-muscle-rich les ions. Proline hydroxylase, a key enzyme for collagen synthesis, was detecte d in most of the foam-cell-containing lesions, but not in smooth-muscle-ric h lesions. Conclusions Atherectomized lesions from patients with coronary stenosis con tained smooth-muscle-rich lesions in restenosis and lipid-laden cellular le sions in both stenosis and restenosis, in which the deposition of oxidized LDL and increased collagen synthesis occur coincidentally. Therefore, the m echanism of atherogenesis may involve coronary stenosis regardless of the o ccurrence of restenosis after PTCA therapy. Coronary Artery Dis 9:551-557 ( C) 1998 Lippincott Williams & Wilkins.