Identifying the role of aortic valve interstitial cells and altered micro-environment on bicuspid aortic valve disease progression.

项目概要/摘要 二叶式主动脉瓣（BAV）是最常见的心脏先天性缺陷， 正常的三个小叶组织。BAV通常以比结构正常的主动脉更快的速度发生病变。 主动脉瓣（AV）最常见的原因是钙积聚，最终导致主动脉瓣狭窄（AS）。当前临床 BAV患者中AS的治疗仅包括手术选择，如AV修复和置换， 替换是比较常见的。生物瓣膜通常用于置换手术， 它们的寿命只有10-15年。在BAV患者的背景下，这些患者倾向于在较早的时间点发病， 生物瓣膜不是无限期的解决方案，很可能需要后续外科手术。 或者，机械瓣膜用于年轻的BAV患者人群，但需要不确定的 需要抗凝剂，这严重影响了患者的生活质量。因此，没有最佳或无限期的手术 目前存在治疗BAV疾病的干预措施。我们实验室和其他人之前的工作已经阐明了 细胞外基质（ECM）组成和结构的差异以及机械性能的差异， AV和BAV之间的应力应变环境。然而，这些变化是如何发生的， 影响BAV间质细胞（BAVIC）功能性重塑行为。此外，还做了有限的工作， 探索BAV疾病是否可能由BAVIC和正常AV之间的内在差异引起 间质细胞（AVIC）。我们假设BAVIC的内在差异，改变的微环境， 并且改变的BAV小叶株通过细胞介导的ECM重塑增强BAV疾病进展 以及由BAVIC群体的表型活化引起的生物合成。我们将讨论这一假设 有以下三个目标： 识别BAV内的3D形态和ECM区域变化。我们将利用国家的- 包括3D小角度光散射、定量组织学和聚焦离子束扫描在内的先进方法 电子显微镜以评估BAV和AV之间ECM的差异。 描绘了生物物理状态和生物合成行为的孤立BAVIC和AVIC内 不同硬度的肽改性的聚（乙二醇）（PEG）水凝胶。我们将评估收缩性 PEG水凝胶内分离的BAVIC和AVIC的生物合成特性，以研究内在的 细胞群之间的差异。 模拟BAV瓣叶应变以评估体外BAVIC重塑行为。在这里，我们将使用单轴 拉伸生物反应器以模拟BAV菌株水平并评估改变的运动学如何影响BAVIC反应。

PROJECT SUMMARY/ABSTRACT The bicuspid aortic valve (BAV) is the most common cardiac congenital defect and contains two, as opposed to the normal three, leaflet tissues. BAVs commonly become diseased at a faster rate than structurally normal aortic valves (AVs) most often due to calcium build up which eventually leads to aortic stenosis (AS). Current clinical treatments for AS in BAV patients consist only of surgical options such as AV repair and replacement, with replacement being the more common. Bioprosthetic valves are routinely used in replacement scenarios despite their limited lifespan of 10-15 years. In the context of BAV patients, who tend to disease at earlier time points in life, bioprosthetic valves are not an indefinite solution and will most likely require follow-up surgical operations. Alternatively, mechanical valves are employed for the younger BAV patient population but require the indefinite need for anticoagulants which substantially hinders patient quality of life. Thus, no optimal nor indefinite surgical intervention currently exists to treat BAV disease. Previous work from our lab and others have elucidated drastic differences in extracellular matrix (ECM) composition and structure as well as differences in the mechanical stress-strain environment between AVs and BAVs. However, it has yet to be elucidated as to how these changes affect BAV interstitial cell (BAVIC) functional remodeling behaviors. In addition, limited work has been done to explore whether BAV disease may be caused by intrinsic differences between the BAVICs and normal AV interstitial cells (AVICs). We hypothesize that the intrinsic differences of BAVICs, the altered microenvironment, and the altered BAV leaflet strains enhance BAV disease progression through cell-mediated ECM remodeling and biosynthesis brought on by phenotypic activation of the BAVIC population. We will address this hypothesis with the following three aims: Identifying the 3D morphological and ECM regional variations within the BAV. We will utilize state-of-the- art methods including 3D small angle light scattering, quantitative histology, and focused-ion beam scanning electron microscopy to assess the differences in ECM between the BAV and AV. Delineating the biophysical state and biosynthetic behaviors of isolated BAVICs and AVICs within peptide-modified poly (ethylene glycol) (PEG) hydrogels of varying stiffness. We will assess the contractile and biosynthetic properties of isolated BAVICs and AVICs within PEG hydrogels to investigate intrinsic differences among the cell groups. Emulating BAV leaflet strains to assess BAVIC remodeling behaviors in vitro. Here we will use a uniaxial stretch bioreactor to emulate BAV strain levels and assess how altered kinematics affect BAVIC responses.