| Abstract: | 血管移植手術時常被用來治療動脈硬化和周邊血管病變。患者自身的血管常不足以提供和重複用來進行繞道或移植手術，因此發展生物性質相容並且不會產生血栓的小管徑血管的人工替代品有急切的必要性。我們實驗室先前已經利用羊膜做為生物性的基底膜並在其上培養豬的內皮細胞，建構成全生物性的原生形人工血管。 為了衡量原生形人工血管中的內皮細胞是否有足夠的血流相容性，我們利用生物反應器 (bio-reactor) 給予原生形人工血管流體切應力 (shear stress) 來觀察血流對人工血管的影響。我們施予人工血管九組不同強度的切應力 (0.5，1，2，3，4，6，8，10，12 dyne/cm2) 二到四天，來研究內皮細胞的附著力，並選擇生理血流切應力12 dyne/cm2分析切應力對於內皮細胞與細胞之間的貼附分子和細胞與基底膜之間貼附分子表現的影響，並以共軛焦螢光顯微鏡和西方點墨法觀察分析。結果顯示施予12 dyne/cm2切應力二天後，人工血管中內皮細胞數量沒有明顯降低，而在12 dyne/cm2切應力刺激二天與四天後，由F-actin的螢光染色，可觀察到細胞明顯排列成單一方向並和液體流向平行。由共軛焦螢光顯微鏡及西方點墨法證明在經過切應力刺激後，PECAM-1、VE-cadherin和integrin β1、integrin αv/β3表現量顯著增加。從以上實驗結果推測由羊膜建構的組織工程人工血管在經過流體切應力處理後，生物相容性更好，對未來動物移植實驗成功的可能性相對提高。
Blood vessel replacements are frequently necessary in the treatment of atherosclerosis and peripheral vascular diseases. The supply of native vessels may not be sufficient for multiple bypass or repeated procedures. It is, therefore, desirable to develop a biocompatible small-diameter artificial blood vessel substitute with no thrombosis concerns. In our previous study, we have fabricated a prototype tissue-engineered blood vessel equivalents (BVEs) by amniotic membrane (AM) as a biological scaffold. The results showed that AM might be an ideal matrix to develop a functional endothelium in BVEs construction. To evaluate whether the endothelial cells in the BVEs could confer the necessary hemocompatible properties, the responses of endothelial cells (ECs) to fluid shear stress were assessed in this study. Nine different shear stresses (0.5, 1, 2, 3, 4, 6, 8, 10, 12 dyne/cm2) were applied to the BVEs in a flow chamber and each shear stress was maintained for 2~4 days to investigate the effects of shear stress on the ECs adhesive strength. The expressions of cell adhesion molecules such as PECAM, VE-cadherin, and focal adhesion molecule, integrins, were analyzed by confocal microscopy and western blot analysis. The data showed that the cell numbers on the AM didn’t decrease after applying the physiological shear stress (12 dyne/cm2) for 2 days. Under this condition, the immunofluorescence staining of F-actin showed that the cells aligned uni-directionally and paralleled with the direction of fluid flow. Confocal immunomicroscopy and Western blot analysis demonstrated that the expressions of PECAM-1, VE-cadherin and integrin β1, integrin αv/β3, increased. From these results, we conclude that the AM-fabricated tissue-engineered BVEs after fluid shear stress are more biocompatible and can be used on the vessel implantation in the animal models. |
