National Institute of Health and Medical Research U1148, Paris, France.
National Institute of Health and Medical Research U1148, Paris, France; Department of Cardiology, Bichat Hospital, Paris, France; Faculty of Medicine Paris-Diderot, University Paris Diderot, Sorbonne Paris Cité, Paris, France.
J Am Coll Cardiol. 2019 Mar 12;73(9):1043-1054. doi: 10.1016/j.jacc.2018.12.042.
Intraleaflet hematomas are associated with advanced stages of aortic valve calcification and suspected to be involved in disease progression. However, the mechanism by which the entry of blood cells into the valves affects the biology of aortic valvular interstitial cells (VICs) remains to be elucidated.
This study sought to evaluate the putative link between intraleaflet hematoma and aortic valve calcification and to assess its pathophysiological implications.
The spatial relationship between calcium deposits and intraleaflet hematomas was analyzed by whole-mount staining of calcified and noncalcified human aortic valves, obtained in the context of heart transplantation and from patients who underwent surgical valve replacement. Endothelial microfissuring was evaluated by en face immunofluorescence and scanning electron microscopic analyses of the fibrosa surface. Red blood cell (RBC) preparations were used in vitro to assess, by immunofluorescence microscopy and Alizarin red staining, the potential impact of intraleaflet hematomas on phenotypic changes in VICs.
Intraleaflet hematomas, revealed by iron deposits and RBCs into the fibrosa, secondary to endothelial microfissuring, were consistently found in noncalcified valves. The contact of primary VICs derived from these valves with RBCs resulted in a global inflammatory and osteoblastic phenotype, reflected by the up-regulation of interleukin-6, interleukin-1β, bone sialoprotein, osteoprotegerin, receptor activator of nuclear factor kappa B, bone morphogenic protein 2, and muscle segment homeobox 2, the production of osteocalcin, and the formation of calcium deposits.
The acquisition of an osteoblastic phenotype in VICs that come into contact with the senescent RBCs of intraleaflet hematomas may play a critical role in the initiation of calcium deposition into the fibrosa of human aortic valves.
瓣叶内血肿与主动脉瓣钙化的晚期阶段有关，疑似参与疾病进展。然而，血细胞进入瓣膜如何影响主动脉瓣间质细胞（VIC）的生物学特性仍有待阐明。
本研究旨在评估瓣叶内血肿与主动脉瓣钙化之间的潜在联系，并评估其病理生理意义。
通过对心脏移植和接受手术瓣膜置换的患者的钙化和非钙化人主动脉瓣进行全染色，分析钙沉积物与瓣叶内血肿之间的空间关系。通过对纤维层表面进行免疫荧光和扫描电镜分析，评估内皮微裂。使用红细胞（RBC）制剂通过免疫荧光显微镜和茜素红染色，评估瓣叶内血肿对 VIC 表型变化的潜在影响。
铁沉积物和 RBC 进入纤维层导致内皮微裂，从而在非钙化瓣膜中始终发现瓣叶内血肿。源自这些瓣膜的原发性 VIC 与 RBC 接触会导致全身性炎症和成骨细胞表型，这反映在白细胞介素 6、白细胞介素 1β、骨涎蛋白、骨保护素、核因子 kappa B 受体激活剂、骨形态发生蛋白 2 和肌肉节同源框 2 的上调、骨钙蛋白的产生和钙沉积物的形成。
与瓣叶内血肿中衰老的 RBC 接触的 VIC 获得成骨细胞表型，可能在人主动脉瓣纤维层钙沉积的起始中起关键作用。
