Atkins Samantha K, Moore Alison N, Sucosky Philippe
Samantha K Atkins, Alison N Moore, Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, United States.
World J Cardiol. 2016 Jan 26;8(1):89-97. doi: 10.4330/wjc.v8.i1.89.
To investigate the role of type-I left-right bicuspid aortic valve (LR-BAV) hemodynamic stresses in the remodeling of the thoracic ascending aorta (AA) concavity, in the absence of underlying genetic or structural defects.
Transient wall shear stress (WSS) profiles in the concavity of tricuspid aortic valve (TAV) and LR-BAV AAs were obtained computationally. Tissue specimens excised from the concavity of normal (non-dilated) porcine AAs were subjected for 48 h to those stress environments using a shear stress bioreactor. Tissue remodeling was characterized in terms of matrix metalloproteinase (MMP) expression and activity via immunostaining and gelatin zymography.
Immunostaining semi-quantification results indicated no significant difference in MMP-2 and MMP-9 expression between the tissue groups exposed to TAV and LR-BAV AA WSS (P = 0.80 and P = 0.19, respectively). Zymography densitometry revealed no difference in MMP-2 activity (total activity, active form and latent form) between the groups subjected to TAV AA and LR-BAV AA WSS (P = 0.08, P = 0.15 and P = 0.59, respectively).
The hemodynamic stress environment present in the concavity of type-I LR-BAV AA does not cause any significant change in proteolytic enzyme expression and activity as compared to that present in the TAV AA.
在不存在潜在遗传或结构缺陷的情况下，研究I型左右二叶式主动脉瓣（LR-BAV）血流动力学应力在胸段升主动脉（AA）凹面重塑中的作用。
通过计算获得三尖瓣主动脉瓣（TAV）和LR-BAV AA凹面的瞬态壁面剪应力（WSS）分布。从正常（未扩张）猪AA凹面切除的组织标本使用剪应力生物反应器在这些应力环境下处理48小时。通过免疫染色和明胶酶谱法，根据基质金属蛋白酶（MMP）表达和活性对组织重塑进行表征。
免疫染色半定量结果表明，暴露于TAV和LR-BAV AA WSS的组织组之间MMP-2和MMP-9表达无显著差异（分别为P = 0.80和P = 0.19）。酶谱光密度测定显示，接受TAV AA和LR-BAV AA WSS的组之间MMP-2活性（总活性、活性形式和潜伏形式）无差异（分别为P = 0.08、P = 0.15和P = 0.59）。
与TAV AA中存在的血流动力学应力环境相比，I型LR-BAV AA凹面中存在的血流动力学应力环境不会导致蛋白水解酶表达和活性发生任何显著变化。
