Siow Richard C M, Mallawaarachchi Chandike M, Weissberg Peter L
Division of Cardiovascular Medicine, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
Cardiovasc Res. 2003 Jul 1;59(1):212-21. doi: 10.1016/s0008-6363(03)00292-x.
Migration of adventitial fibroblasts, in addition to smooth muscle cell proliferation, plays a role in neointima formation following vascular injury. Previous studies have not directly addressed whether endogenous adventitial cells migrate towards the intima following balloon injury in the absence of medial dissection. We have employed an in vivo gene transfer technique to the rat carotid artery to directly label adventitial fibroblasts prior to balloon injury.
An adenoviral vector coordinating expression of nuclear targeted beta-galactosidase (AdLacZ) suspended in pluronic gel was applied to the perivascular surface of left carotid arteries of male Sprague-Dawley rats. Balloon catheter mediated vascular injury was performed on these arteries 4 days later and animals killed at 3, 7 and 14 days after injury.
Expression of LacZ up to 14 days after application of the adenovirus was restricted only to the adventitia of uninjured arteries and absent from untransfected right carotid arteries. However, following balloon catheter injury, LacZ positive cells were observed within the medial layer of vessels by 3 days, and contributed to the population of cells within the neointima at 7-14 days. Adventitial cells in uninjured arteries did not express smooth muscle alpha-actin but after injury, LacZ positive cells migrating towards the lumen exhibited alpha-actin immunostaining, suggesting their change to a myofibroblastic phenotype.
These findings provide direct evidence that adventitial fibroblasts migrate and contribute to neointima formation after balloon injury and show that in vivo gene transfer to the adventitia results in sustained transgene expression capable of labelling migrating adventitial cells within the media and neointima of injured vessels.
除平滑肌细胞增殖外，外膜成纤维细胞的迁移在血管损伤后的新生内膜形成中起作用。以往研究未直接探讨在无中膜剥离的情况下，球囊损伤后内源性外膜细胞是否会向内膜迁移。我们采用体内基因转移技术对大鼠颈动脉进行处理，在球囊损伤前直接标记外膜成纤维细胞。
将悬浮于普朗尼克凝胶中的、能协调表达核靶向β-半乳糖苷酶的腺病毒载体（AdLacZ）应用于雄性Sprague-Dawley大鼠左颈动脉的血管周围表面。4天后对这些动脉进行球囊导管介导的血管损伤，并在损伤后3天、7天和14天处死动物。
腺病毒应用后长达14天，LacZ的表达仅局限于未损伤动脉的外膜，未转染的右颈动脉中未检测到。然而，球囊导管损伤后，3天时在血管中膜层观察到LacZ阳性细胞，7 - 14天时这些细胞参与了新生内膜中的细胞群体构成。未损伤动脉中的外膜细胞不表达平滑肌α-肌动蛋白，但损伤后，向管腔迁移的LacZ阳性细胞表现出α-肌动蛋白免疫染色，表明它们转变为肌成纤维细胞表型。
这些发现提供了直接证据，表明外膜成纤维细胞在球囊损伤后会迁移并参与新生内膜形成，并且表明对外膜进行体内基因转移可导致持续的转基因表达，能够标记损伤血管中膜和新生内膜内迁移的外膜细胞。
