Mozdzen Laura C, Thorpe Stephen D, Screen Hazel R C, Harley Brendan A C
University of Illinois, Chemical and Biomolecular Engineering, 600 S. Mathews St, Urbana, IL, 61801, USA.
School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, E1 4NS, London, UK.
Adv Healthc Mater. 2016 Jul;5(14):1731-9. doi: 10.1002/adhm.201600181. Epub 2016 Jun 1.
The tendon-bone junction is a unique, mechanically dynamic, structurally graded anatomical zone, which transmits tensile loads between tendon and bone. Current surgical repair techniques rely on mechanical fixation and can result in high re-failure rates. A new class of collagen biomaterial that contains discrete mineralized and structurally aligned regions linked by a continuous interface to mimic the graded osteotendinous insertion has been recently described. Here the combined influence of graded biomaterial environment and increasing levels of applied strain (0%-20%) on mesenchymal stem cell (MSC) orientation and alignment have been reported. In osteotendinous scaffolds, which contain opposing gradients of mineral content and structural alignment characteristic of the native osteotendinous interface, MSC nuclear, and actin alignment is initially dictated by the local pore architecture, while applied tensile strain enhances cell alignment in the direction of strain. Comparatively, in layered scaffolds that do not contain any structural alignment cues, MSCs are randomly oriented in the unstrained condition, then become oriented in a direction perpendicular to applied strain. These findings provide an initial understanding of how scaffold architecture can provide significant, potentially competitive, feedback influencing MSC orientation under applied strain, and form the basis for future tissue engineering efforts to regenerate the osteotendinous enthesis.
肌腱-骨结合部是一个独特的、机械动力学的、结构分级的解剖区域,它在肌腱和骨之间传递拉伸载荷。目前的手术修复技术依赖于机械固定,可能导致较高的再次失败率。最近描述了一种新型胶原生物材料,其包含由连续界面连接的离散矿化和结构排列区域,以模拟分级的骨腱插入。本文报道了分级生物材料环境和增加的应用应变水平(0%-20%)对间充质干细胞(MSC)取向和排列的综合影响。在含有天然骨腱界面特征性矿物质含量和结构排列相反梯度的骨腱支架中,MSC细胞核和肌动蛋白排列最初由局部孔隙结构决定,而施加的拉伸应变会增强细胞在应变方向上的排列。相比之下,在不含任何结构排列线索的分层支架中,MSC在未受应变的条件下随机取向,然后在与施加应变垂直的方向上取向。这些发现初步了解了支架结构如何在施加应变的情况下提供显著的、潜在竞争性的反馈来影响MSC取向,并为未来再生骨腱结合部的组织工程努力奠定了基础。