経皮的冠動脈形成術後再狭窄病変でのheparin-binding epidermal growth factor-like growth factorの血管平滑筋細胞内発現亢進 : 冠動脈アテレクトミー切除標本を用いたin situハイブリダイゼーション法による検討

Abstract

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is one of the growth factors for vascular smooth muscle cells (SMC) and is implicated in the pathogenesis of human atherosclerosis. But there is no report for the role of HB-EGF in the restenosis of human coronary arteries after percutaneous transluminal corohary angio- plasty (PTCA). To elucidate the role of HB-EGF in restenosis after PTCA using in situ hybridization in specimehs obtained by directional coronary atherectomy (DCA), the expression of HB- EGF mRNA in both restenosis and de novo stenotic lesions were investigated. Histological findings and the expression of HB-EGF mRNA in 17 patients with coronary stenotic lesions were examined : 7 with restenosis lesions after PTCA (the restenosis group) and 10 with primary lesions (the de novo group). The intimal lesions were classified into atherosclerotic plaques and intimal proliferation, and the area of each component were measured. There were no significant differences between the two groups with regard to age, gender, number of diseased vessels, target lesion of DCA, coronary risk factor, or prevalence of each intimal lesion. Percent area of intimal proliferation in the restenosis group was significantly greater than that in the de novo group (66±22% vs. 21±27%, p<0.05). As for in situ hybridization, expression.of HB-EGF mRNA was detected in the cytoplasm of SMC in lesions showing intimal proliferation. Prevalence of HB-EGF mRNA expression in the restenosis group was significantly greater than that in the de novo group (71% vs. 10%, p<0.05). In the restenosis group all patients, in whom HB-EGF mRNA expression was detected, underwent DCA less than 6 months after angioplasty. These data suggest that HB-EGF might play an important role in the progression of restenosis after PTCA through intimal proliferation and changes of SMC phenotype.