Aims: Tissue engineering seeks to improve the longevity of prosthetic heart valves, but the cell source of choice has yet to be determined. This study aimed to establish a mechanistic rationale supporting the suitability of human adventitial pericytes (APCs). Methods and Results: Antigenically APCs were immunomagnetically sorted from saphenous vein leftovers of patients undergoing coronary artery surgery and antigenically characterized for purity. Unlike bone marrow-derived mesenchymal stromal cells (BM-MSCs), APCs were resistant to osteochondrogenic induction by high phosphate (HP), as assessed by cytochemistry and expression of osteogenic markers. MiR-132 is natively expressed by APCs, with copy numbers being enhanced by HP stimulation. In silico bioinformatic analysis, followed by luciferase assays in HEK293 cells and miR-132 titration using agomiR and antagomiR in APCs, demonstrated that several osteochondrogenic genes were negatively regulated by miR-132. Among these, the glycolytic marker GLUT1 was downregulated in HP-stimulated APCs. In contrast to BM-APCs, APCs showed no increase in glycolysis under HP. Interestingly, incubation with APC-derived conditioned medium conferred swine cardiac valves with resistance to osteogenic transformation by HP; whereas, conditioned media from miR-132-knocked-down APCs failed to prevent the expression of these markers. Finally, we demonstrated the feasibility of using APCs to engineer bovine pericardium patches. APCs proliferate in the patch and secrete factors able to attract aortic endothelial cells under HP. Conclusions: Human APCs are resistant to calcification compared with BM-MSCs and convey the anti-calcific phenotype to heart valves through miR-132. These findings may open new important avenues for prosthetic valve cellularization.

中文翻译：

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大隐静脉为人工心脏瓣膜工程提供了独特的抗钙化周细胞来源

目的：组织工程学试图改善人工心脏瓣膜的寿命，但尚未确定选择的细胞来源。这项研究旨在建立一种机制，以支持人类外膜周细胞（APC）的适用性。方法和结果：从接受冠状动脉手术的患者的大隐静脉残留物中进行免疫磁性分选，并对抗原进行纯度鉴定。与骨髓来源的间充质基质细胞（BM-MSC）不同，APC对高磷酸盐（HP）诱导的骨软骨形成具有抗性，如通过细胞化学和成骨标记物的表达所评估的。MiR-132由APC天然表达，HP刺激增强了拷贝数。在计算机生物信息学分析中，随后在HEK293细胞中进行萤光素酶测定，并在APC中使用agomiR和antagomiR进行miR-132滴定，证明了若干骨软骨形成基因受到miR-132负调控。其中，糖酵解标记物GLUT1在HP刺激的APC中被下调。与BM-APC相比，APC在HP下的糖酵解没有增加。有趣的是，与APC衍生的条件培养基一起孵育可赋予猪心脏瓣膜以抵抗HP致骨转化的能力。然而，来自miR-132敲除的APC的条件培养基无法阻止这些标记的表达。最后，我们证明了使用APC改造牛心包膜的可行性。APC在斑块中增殖，并分泌能够吸引HP下主动脉内皮细胞的因子。结论：与BM-MSC相比，人类APC对钙化有抗性，并通过miR-132将抗钙化表型传递至心脏瓣膜。这些发现可能为人工瓣膜细胞化开辟新的重要途径。