Spatially and temporally distinct expression of fibroblast connexins after sheep ventricular infarction
Spatially and temporally distinct expression of fibroblast connexins after sheep ventricular infarction
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DOI：
10.1016/j.cardiores.2004.01.027
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发表时间：
2004-05-01
影响因子：
10.8
通讯作者：
Green, CR
中科院分区：
文献类型：
--
作者：
Camelliti, P;Devlin, GP;Green, CR
目的：心肌梗死导致心肌细胞和成纤维细胞组织的广泛变化，以及间隙连接蛋白表达的变化。在缺血后的即刻，再灌注引起过度收缩，扩散坏死病变。进一步进行性梗死持续数周。在再灌注损伤中，非特异性缝隙连接通道解偶联剂庚醇限制坏死。我们假设缝隙连接偶联和成纤维细胞侵袭通过缝隙连接介导的旁观者效应为进行性梗死提供了基质。方法：采用绵羊冠状动脉闭塞性梗死模型，分别于梗死后12、24、48 h，6、12、30 d（d）采集心肌标本。将间隙连接连接蛋白Cx40、Cx43和Cx45的免疫组织化学标记与成纤维细胞（抗波形蛋白）和肌细胞（抗肌桥蛋白）的细胞特异性标志物组合。采用免疫双标和免疫三标及共聚焦显微镜观察心肌梗死后心肌细胞形态、成纤维细胞含量和缝隙连接表达的变化。定量间隙连接蛋白水平和成纤维细胞数量。结果：在缺血12小时内，心肌细胞活力受损的小岛在缺血区域。这些岛扩散并融合成更大的梗死区，直到梗死后12天。此后，梗死区和边缘区的存活肌细胞似乎变得稳定。在远离梗死的地方，即使在30天后也经常观察到持续的肌细胞破坏。Cx43在12 d内从闰盘重新分布到结构受损的肌细胞的侧面。表达Cx45的成纤维细胞在24 h内浸润损伤区域，在梗死后6-12 d变得最多，Cx45水平在6 d达到峰值。随后，观察到表达Cx43的成纤维细胞，并且相关的Cx43标记在30天的观察期内增加，尽管成纤维细胞数量在12天后下降。Cx40仅见于血管内皮。结论：通过肌细胞肌节破坏和随后的细胞损失鉴定的进行性梗死与成纤维细胞侵袭和间隙连接重塑平行发生。两种成纤维细胞表型发生在梗死，表达Cx43或Cx45。偶联的成纤维细胞可能在心肌梗死后的组织重塑中发挥许多作用，包括通过间隙连接介导的旁观者效应为进行性梗死提供可能的底物。(C)2004年欧洲心脏病学会。Elsevier B. V.出版，保留所有权利。
Objectives: Myocardial infarction leads to extensive changes in the organization of cardiac myocytes and fibroblasts, and changes in gap junction protein expression. In the immediate period following ischemia, reperfusion causes hypercontraction, spreading the necrotic lesion. Further progressive infarction continues over several weeks. In reperfusion injury, the nonspecific gap junction channel uncoupler heptanol limits necrosis. We hypothesize that gap junction coupling and fibroblast invasion provide a substrate for progressive infarction via a gap junction mediated bystander effect. Methods: A sheep coronary occlusion infarct model was used with samples collected at 12, 24 and 48 h, and 6, 12 and 30 d (days) post-infarction. lmmunohistochemical labelling of gap junction connexins Cx40, Cx43, and Cx45 was combined with cell-specific markers for fibroblasts (anti-vimentin) and myocytes (anti-myomesin). Double and triple immunolabelling and confocal microscopy were used to follow changes in cardiac myocyte morphology, fibroblast content and gap junction expression after myocardial infarction. Gap junction protein levels and fibroblast numbers were quantified. Results: Within 12 h of ischemia, myocyte viability is impaired within small islands in the ischemic region. These islands spread and fuse into larger infarct zones until 12 d post-infarction. Thereafter, surviving myocytes within the infarct and in the border-zone appear to become stabilized. Distant from the infarct, continuing myocyte disruption is regularly observed, even after 30 d. Cx43 becomes redistributed from intercalated discs to the lateral surface of structurally compromised myocytes within 12 d. Cx45 expressing fibroblasts infiltrate the damaged region within 24 h, becoming most numerous at 6-12 d post-infarction, with peak Cx45 levels at 6 d. Later, Cx43 expressing fibroblasts are observed, and the related Cx43 label increases over the 30 d observation period, even though fibroblast numbers decline after 12 d. Cx40 was only seen in vascular endothelium. Conclusions: Progressive infarction, identified by myocyte sarcomere disruption and subsequent cell loss, occurs in parallel with fibroblast invasion and gap junction remodeling. Two fibroblast phenotypes occur within infarcts, expressing either Cx43 or Cx45. Coupled fibroblasts may play a number of roles in tissue remodeling following myocardial infarction, including provision of a possible substrate for progressive infarction via a gap junction mediated bystander effect. (C) 2004 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.