Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush Veterinary Centre Roslin, Mid-Lothian EH25 9RG, Scotland, UK.
Vet J. 2013 Aug;197(2):388-94. doi: 10.1016/j.tvjl.2013.01.027. Epub 2013 Mar 7.
Morphological and functional changes in endothelial and interstitial cells are considered central to myxomatous degeneration of the canine mitral valve (endocardiosis). The aim of this study was to describe and quantify changes in valve endothelial cells (VECs), interstitial cells (VICs) and the extra-cellular matrix (ECM) of the sub-endothelial zone of diseased valves using a combination of transmission electron microscopy, stereology and computer-aided image analysis. Marked degradation of the endothelium was evident in diseased valves, which coincided with significant degradation of the local ECM (P<0.001). There were decreases and increases in the numbers of VECs and VICs, respectively, in diseased valves, with particular accumulation of VICs subjacent to the valve surface (P<0.01). Overall, VICs were more pleomorphic than VECs in both normal and diseased valves, but for VECs, the degree of pleomorphism was significantly different in diseased valves (P<0.0001). The findings of the study confirm that canine myxomatous mitral valve disease is associated with marked endothelial damage, with attendant proliferation of subjacent activated myofibroblasts. The fact that similar endothelial changes are present in normal valves suggests these processes not only contribute to valve pathology, but may also represent life-long valve remodelling.
内皮细胞和间质细胞的形态和功能变化被认为是犬二尖瓣粘液样变性（心内膜炎）的核心。本研究的目的是使用透射电子显微镜、体视学和计算机辅助图像分析相结合的方法，描述和量化病变瓣膜内皮细胞（VECs）、间质细胞（VICs）和细胞外基质（ECM）在下皮细胞区的变化。病变瓣膜的内皮明显退化，与局部 ECM 的显著降解一致（P<0.001）。病变瓣膜中 VECs 和 VICs 的数量分别减少和增加，VICs 特别在下瓣膜表面下积聚（P<0.01）。总体而言，正常和病变瓣膜中的 VICs 比 VECs 更具多形性，但对于 VECs，病变瓣膜中的多形性程度明显不同（P<0.0001）。本研究的发现证实，犬粘液样二尖瓣疾病与明显的内皮损伤有关，伴有下方激活的肌成纤维细胞的增殖。正常瓣膜中存在类似的内皮变化这一事实表明，这些过程不仅有助于瓣膜病理学，而且可能代表终生的瓣膜重塑。
