RGD改質海藻酸鈉微球包覆三維培養人類脂肪幹細胞

Abstract

對於組織的再生和血運重建，植入細胞療法是一個具有極大潛力的治療方式。細胞療法的目標是更換並修復或加強受損組織或器官的功能。然而，有兩個問題是在細胞移植或異種移植前需要解決的主要問題，如此一來才可以達到臨床應用所能接受的標準：控制免疫排斥反應以及控制植入的細胞其增殖的情形。藉由有機或生物衍生之材料，如海藻酸鈉，來包覆細胞的方法，似乎是一個很好的方式來實現上述的目標。 我們利用三維生物培養系統有效的提高了幹細胞的分化能力，且我們藉著利用具有磁懸浮的三維細胞培養系統，即搭配外面塗有仿生物表面的海藻酸鈉基底微載體，來培養初代幹細胞，以使得幹細胞能夠培養維持在三維環境中。 本研究探討了以接枝RGD(精氨酸-甘氨酸-天冬氨酸)之生物性材料實際用於動物模型修復下肢缺血的可能性。在這項實驗中，我們對RGD接枝並混合有高、低兩種分子量的海藻酸鈉微囊球固定脂肪幹細胞hASCs，進行了許多實驗研究。在體外的實驗研究表明，RGD接枝的海藻酸鈉可以成功促進人類脂肪幹細胞(hASCs)的貼附。 基於不同的細胞外基質(ECM)會影響細胞的行為，在接枝RGD的海藻酸鈉固定化細胞方面，顯示出接枝RGD之海藻酸鈉包覆細胞會使得細胞有較高的存活率，整體存活率都高於80％，且有助於促進血管生長因子的表達。我們認為使用成人脂肪幹細胞作為治療下肢缺血患者因病情嚴重而受到影響的病症發展，是個有潛力成為一種成熟且穩定的幹細胞治療方式。

Cell-based therapies offer an attractive approach for revascularization and regeneration of tissues. The aim of cell therapy is to replace, repair, or enhance the function of damaged tissues or organs. There are, however, two major drawbacks that need to be resolved before cellular allografts or xenografts can achieve clinical acceptance: control of immune rejection and control of implanted cell proliferation. Cell encapsulation by means of organic or biologically derived matrixes, such as alginate, appears to be an avenue by which these goals may be accomplished. Three dimensional biology promises to enable efficient differentiation of stem cells. We made use of a magnetically levitating 3D cell culture system, based on alginate microcarriers coated with a biomimetic surface, that supports the growth of primary and stem cells in 3D envirument. The present study was undertaken to explore the possible therapeutic efficacy of RGD (Arg-Gly-Asp) peptide-linked biomaterial in repairing the lower limb ischemia of a rodent model. In this work, hASCs immobilized in RGD-coupled alginate microspheres, with a binary composition of high and low molecular weight alginate, were investigated. The in vitro study of hASCs demonstrated that RGD-coupled alginate promoted cell adherence to the matrix. Since different extra-cellular matrix proteins (ECM) influence the cells behavior, immobilized within RGD-alginate microspheres showed metabolic activity, with an overall viability higher than 80%, growth and increase angiogenic growth factor expression. We believe that the use of adult stem cell therapy in ischemia patients allows for the development of new mature and stable capillaries in patients affected by the severe condition.