臍帶間質組織衍生內皮前驅細胞經由HIF-1α/IL-8
減少糖尿病鼠下肢缺血性傷害

由於逐漸攀高的糖尿病盛行率及其防治與治療已被視為非常重要的課題。嚴重糖尿病可引起諸多併發症。其中，病患的足部血管病變造成微循環不良，更是容易導致糖尿病患者下肢傷口不易癒合及其相關感染的產生，嚴重時常會導致下肢截肢。近幾年來研究發現骨髓衍生之內皮前驅細胞(EPC)可以降低動物組織缺血性傷害，促使血管新生並提高存活率。隨著其他器官幹細胞的發現以及對幹細胞特性，包括如何幫助受損器官修補之潛能的瞭解，運用幹細胞於治療缺血性傷害是一新的策略。有別於單一藥物的治療，幹細胞可於受傷組織分泌細胞激素、改善血管功能或直接分化為需要的細胞來幫助血管再生。本篇研究之主要目的想要藉由臍帶間質幹細胞所分化之內皮前驅細胞(WJ-EPC)，植入至糖尿病鼠之缺血下肢，探討EPC影響糖尿病小鼠之缺血性傷害及其相關機轉。首先，藉由股動脈截斷術造成下肢缺血，然後將EPC植入至糖尿病鼠下肢缺血的肌肉內，藉由下肢血流、外觀等觀察來驗證植入EPC的治療效果。實驗結果發現，在缺血性下肢糖尿病鼠的血流會降低、血管密度減少以及增加骨骼肌細胞凋亡。而這些組織傷害可藉由植入EPC而被明顯減緩。除此之外，以免疫組織化學染色法鑑別，發現植入骨骼肌之EPC在缺氧的微環境下有表現缺氧誘導因子(Hypoxia-inducible factor-1a，HIF-1α)及介白素8 ( interleukin-8，IL-8)。在體外實驗方面，我們將EPC培養在缺氧環境下，發現EPC會大量表現HIF-1α並且可在細胞培養液中測得大量的IL-8。此外，我們以在缺氧所獲得EPC培養液(CM-H)與骨骼肌細胞株(NOR)共同培養在缺氧環境中，結果發現CM-H可以降低骨骼肌細胞之促細胞凋亡蛋白質的表現量、增加骨骼肌細胞抗細胞凋亡蛋白質的表現量以及促進EPC的移動性及脈管形成。上述這些現象在轉染HIF-1α siRNA 或IL-8 siRNA至EPC後，其缺氧所獲得EPC培養液不再具有保護骨骼肌細胞免於細胞凋亡的功效，也失去促進EPC的移動性及脈管形成的能力。綜合本研究結果顯示，WJ可當為EPC的主要來源，同時在糖尿病缺血性組織疾病的臨床治療，WJ-EPC的治療可視為一新穎性策略療法。在本研究中，植入EPC至糖尿病鼠的缺血性下肢可經由HIF-1α/IL-8訊號路徑減緩傷害，所以EPC及其訊號機轉的保護作用扮演一非常重要角色。

關鍵字

內皮前驅細胞；缺氧誘導因子；介白素8

並列摘要

Peripheral arterial diseases, the major complication of diabetes, can result in lower limb amputation. As endothelial progenitor cells (EPCs) are involved in neovascularization, the study was to examine whether EPCs isolated from Wharton’s jelly (WJ-EPCs) of the umbilical cord, a rich source of mesenchymal stem cells, could reduce ischemia-induced hind limb injury in diabetic mice. We evaluated the effects of WJ-EPC transplantation on hind limb injury caused by femoral artery ligation in mice with streptozotocin (STZ)-induced diabetes. We found that the ischemic hind limb in mice with streptozotocin-induced diabetes showed decreased blood flow and capillary density and increased cell apoptosis and that these effects were significantly inhibited by injection of WJ-EPCs. In addition, HIF-1α and IL-8 were highly expressed in transplanted WJ-EPCs in the ischemic skeletal tissues and were present at high levels in hypoxia-treated cultured WJ-EPCs. Moreover, incubation of the NOR skeletal muscle cell line under hypoxic conditions in conditioned medium from EPCs cultured for 16 h under hypoxic conditions resulted in decreased expression of pro-apoptotic proteins and increased expression of anti-apoptotic proteins. The inhibition of HIF-1α or IL-8 expression by EPCs using HIF-1α siRNA or IL-8 siRNA, respectively, prevented this change in expression of apoptotic-related proteins. Wharton’s jelly in the umbilical cord is a valuable source of EPCs and transplantation of these EPCs represents an innovative therapeutic strategy for treating diabetic ischemic tissues. The HIF-1α/IL-8 signalling pathway plays a critical role in the protective effects of EPCs in the ischemic hind limb of diabetic mice.

並列關鍵字

endothelial progenitor cells ； Hypoxia-inducible factor ； interleukin-8

參考文獻

Anzalone R, Lo Iacono M, Corrao S, Magno F, Loria T, Cappello F, Zummo G, Farina F, La Rocca G. New emerging potentials for human Wharton's jelly mesenchymal stem cells: immunological features and hepatocyte-like differentiative capacity. Stem Cells and Development. 2010; 19: 423-438.

Asahara T, Murohara T, Sullivan A, Silver M, van der Zee R, Li T, Witzenbichler B, Schatteman G, Isner JM. Isolation of putative progenitor endothelial cells for angiogenesis. Science. 1997; 275: 964-966.

Bakker K, Apelqvist J, Schaper NC. Practical guidelines on the management and prevention of the diabetic foot 2011. Diabetes/Metabolism Research and Reviews. 2012; 28: 225-231.

Baksh D, Yao R and Tuan RS. Comparison of proliferative and multilineage differentiation potential of human mesenchymal stem cells derived from umbilical cord and bone marrow. Stem Cells. 2007; 25: 1384-1392.

Bento CF, Pereira P. Regulation of hypoxia-inducible factor 1 and the loss of the cellular response to hypoxia in diabetes. Diabetologia. 2011; 54: 1946-1956.

國際替代計量

臍帶間質組織衍生內皮前驅細胞經由HIF-1α/IL-8 減少糖尿病鼠下肢缺血性傷害

全文下載

主題瀏覽