Dainese Luca, Guarino Anna, Burba Ilaria, Esposito Grazia, Pompilio Giulio, Polvani GianLuca, Rossini Alessandra
Department of Cardiovascular Surgery, University of Milan, Centro Cardiologico Monzino IRCCS, Milan, Italy.
J Heart Valve Dis. 2012 Jan;21(1):125-34.
The adult human heart contains a cardiac mesenchymal stromal cell (CStC) population with residual cardiovascular plasticity. The study aim was to investigate the ability of CStCs to populate decellularized aortic homograft leaflets, without mechanical stimulation.
The ability of CStCs to acquire valve endothelial and interstitial cell phenotypes was tested using in vitro assays. First, trypsin-decellularized aortic leaflets were seeded with CStCs under static conditions; tissue section analyses were then performed before and after decellularization, and at 10, 20, and 30 days after reseeding.
Following in vitro treatment, the CStCs differentiated along the endothelial lineage, as shown by their capacity to uptake acetylated low-density lipoprotein and to secrete the pro-angiogenic factor, vascular endothelial growth factor. After seeding, CStCs were able to adhere to the leaflet surface, rescuing up to the 90% of the original cell density and expressing the mature endothelial marker, von Willebrandt factor. The CStC supernatants were also positive for matrix metalloprotease-2 (MMP-2), which confirmed the ability of these cells to penetrate within the leaflet structure; this also suggested that CStCs, once engrafted, would contribute to the extracellular matrix turnover. Accordingly, although at a lower efficiency, CStC repopulation was also evident in the inner portions of the leaflet.
Seeded CStCs were able to reconstitute, without mechanical stimulation, an endothelial-like layer and to partially infiltrate decellularized homograft leaflets. Hence, CStCs appear to be a potentially useful cell type for engineered heart valves.
成年人心脏中含有具有残余心血管可塑性的心脏间充质基质细胞（CStC）群体。本研究旨在探究CStC在无机械刺激情况下植入去细胞化主动脉同种异体移植瓣叶的能力。
采用体外试验检测CStC获得瓣膜内皮细胞和间质细胞表型的能力。首先，在静态条件下将经胰蛋白酶去细胞化的主动脉瓣叶接种CStC；然后在去细胞化前后以及重新接种后10、20和30天进行组织切片分析。
体外处理后，CStC沿内皮细胞谱系分化，表现为摄取乙酰化低密度脂蛋白和分泌促血管生成因子血管内皮生长因子的能力。接种后，CStC能够黏附于瓣叶表面，恢复高达90%的原始细胞密度，并表达成熟内皮细胞标志物血管性血友病因子。CStC培养上清液中基质金属蛋白酶-2（MMP-2）也呈阳性，这证实了这些细胞穿透瓣叶结构的能力；这也表明CStC一旦植入，将有助于细胞外基质的更新。因此，尽管效率较低，但在瓣叶内部也明显可见CStC的重新填充。
接种的CStC在无机械刺激的情况下能够重构类似内皮细胞的层，并部分浸润去细胞化同种异体移植瓣叶。因此，CStC似乎是用于工程心脏瓣膜的一种潜在有用的细胞类型。
