Therapeutic Angiogenesis Using Amniotic Fluid-derived Stem Cells
| Autor: | Yen-WenLiu, 劉嚴文 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 Artery occlusive diseases, including coronary artery disease, peripheral artery occlusive disease, and cerebrovascular disease, are major health issues that affect a large proportion of the adults, especially among aging population. Although there are several therapeutic strategies for artery occlusive diseases, i.e. optimal medical treatment and revascularization either by endovascular intervention or by open surgery, the prognosis is not satisfied. Therefore, how to improve blood perfusion in ischemic tissues should play a critical role in improving prognosis of patients with artery occlusive diseases. Previous studies highlighted the necessity of revascularization and reported that bone marrow-derived progenitor cells significantly enhanced cardiac repair by promoting neoangiogenesis. Consequently, to achieve efficient revascularization in ischemic regions is essential for restoring blood perfusion and physiologic function. Angiogenesis is a tightly controlled process where endothelial cells proliferation and migration is regulated by secreted factors as well as by surrounding cells and matrix. However, mature endothelial cells possess limited regenerative capacity. Recently, mounting evidence showed that stem cells, such as endothelial progenitor cells, bone marrow stem cells, or cord blood stem cells, has been used to induce neovascularization in animal models of limb and myocardial ischemia, but unfortunately, the therapeutic efficacy of these stem cells is controversial. It is well-known that human embryonic stem cell (hESC) is pluripotent and can differentiate into a wide range of cell types representing the 3 primary embryonic lineages of mesoderm, ectoderm, and endoderm. However, the use of hESCs for research or therapeutic purposes has been constrained by several issues: complex social and ethical considerations, immune rejection reactions, and tumors formation in recipients. Amniotic fluid-derived stem cells (AFSCs) are known to have a high renewal capacity and great differentiation potency. Unlike hESCs, the AFSCs do not form tumors in severe combined immunodeficient mice, and ASFC research does not raise profound ethical issues. Atala and his colleagues demonstrated that AFSCs are pluripotent and can be directed into a wide spectrum of cell types. Therefore, we conducted this study to test whether AFSCs can function as a cell source for therapeutic angiogenesis in a mouse hindlimb ischemia model: (1) to prove in vitro that AFS cells can be differentiated into endothelial lineage cell (EC), (2) to examine the in vivo therapeutic efficacy of AFSC or AFSC- derived EC (AFSC-EC) transplantation in a nude mice model of hindlimb ischemia, and (3) to identify the possible mechanisms of neoangiogenesis induced by AFSCs or AFSC-ECs. We differentiated human AFSCs into ECs in vitro, as evidenced by expression of endothelial cell markers, and capillary-like network formation on Matrigel. One day after high ligation of the external iliac artery in athymic nude mice, AFSC-ECs were intramuscularly injected into ischemic limbs. As compared to AFSCs, HUVECs, and medium, intramuscular AFSC-EC injection into the ischemic regions improved limb salvage, restored blood perfusion, and significantly increased capillary and arteriole densities. We did not find any evidence of acute rejection or tumor formation in nude mice after intramuscular AFSC-EC injection, and most importantly, transplanted AFSC-ECs survived in the ischemic tissue. Those transplanted AFSC-ECs were incorporated into vessels in the ischemic region, as confirmed by immunofluorescent staining for human smooth muscle 22α or von Willebrand factor. Matrix metalloproteinase (MMP)-9 might stimulate VEGF-A release from AFSC-ECs and thus induce neovascularisation. Our study indicates that AFSC-ECs were a suitable cell source for the treatment of artery occlusive diseases with therapeutic angiogenesis. AFSC-EC transplantation has the potential to promote therapeutic angiogenesis in vivo by facilitating neovascularization in a mouse model of ischemia. We conclude that AFSC-ECs can act as a novel source of xenograft, even allograft, transplantation cells for therapeutic angiogenesis in the treatment of ischemic diseases. In the future, AFSCs might be useful for autologous as well as nonautologous regenerative therapies via matching of histocompactible donor cells with recipients. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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