2010-08-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/644083摘要：肝臟疾病的細胞治療，可應用在遺傳性或後天的肝臟疾病，目前大多的研究仍在動物實驗階段，進入臨床試驗仍屬少數。肝臟細胞治療需克服的困難有：細胞來源的不足，細胞移植後在肝臟內的再生性低，各種不同疾病模式之移植效果差異很大，且動物模式移植使用之藥物，大多有毒性，無法直接應用在人體。在過去幾年的研究中，我們已引進bsep/spgp 基因剔除小鼠 (第二型進行性肝內膽汁滯留動物模式)，持續研究病理變化及細胞治療。膽酸排出蛋白(bsep)是肝細胞膽小管傳送蛋白，負責將膽汁酸排到膽道，也是膽汁流的主要動力，是肝細胞最重要的功能之一。我們首先發表骨髓移植可成功在肝臟內發現少量移植入之肝細胞，並改善膽汁排出功能；另外，也進行成鼠肝細胞治療實驗，我們給予小鼠膽汁酸餵食後，可增加細胞植入的效率，觀察到植入細胞可以繼續生長約4-6周的時間。膽汁酸是脊椎動物體內自然合成的物質，負責腸道的脂肪及脂溶性蛋白質消化吸收，生物體有複雜的調控機制維持膽汁酸代謝的恆定，膽汁酸也和肝細胞生長及凋亡有關；在本計畫中，我們將確立膽汁酸在bsep+/+ 及 -/- 小鼠之毒性及對於肝細胞生長及凋亡之影響，也將近一步研究，膽汁酸對於捐贈細胞及bsep 缺乏細胞之毒性及細胞增生之不同反應及機制；並找到膽汁酸使用在肝細胞移植之理想比例；並確立肝細胞移植在肝內膽汁治療模式的長期改善及治療效果。為了增加細胞移植的來源，我們也將研究中後期胚胎肝母細胞使用在細胞治療之可能性，研究肝母細胞之膽汁傳送相關蛋白的表現，並利用膽汁酸影響胚胎肝母細胞的分化及發育，探討肝母細胞應用在移植之可能性。本研究之結果，將對於肝臟細胞治療的臨床應用，提供重要的基礎，也對於膽汁酸代謝對於肝細胞生長、凋亡及發育的角色，以及胚胎肝細胞用於細胞治療的可能性，有深入的探討；本計畫之成果將可應用於推動肝臟疾病的創新治療，例如基因治療及幹細胞治療。<br> Abstract: Experimental cell therapies for treating acute or inherited metabolic liverdiseases have been explored. The major limitations to cell therapy include theavailability of the cell source, limited repopulation capacity, highly variable responsesin different disease types, and high risk surgery/toxic agents that prevent the applicationin human.We have previously used a model of inherited chronic cholestatic liver disease,bsep knockout mice for cell therapy. Bile salt export pump (bsep) is a canaliculartransporter that mediates the most important physiological function of the liver:bile-acid dependent bile flow. Our previous study using bone marrow celltransplantation or hepatocyte transplantation in this model has resulted in low levels ofdonor cell repopulation. But further experiments using bile acid-modified diet havelargely increased the hepatocyte transplantation efficiency.Bile acids are naturally occurring molecules that are essential for digestion forlipid and lipid-soluble vitamins. Bile acids homeostasis is tightly regulated and isclosely related to bile flow and lipid metabolism, as well as growth and apoptosis ofhepatocytes. In this project we will explore the roles of bile acids and the mechanismsin modulating growth and death of hepatocytes, and different responses in the bsep +/+and -/- mice in terms of cytotoxicity and proliferation. By determining the optimal dosesof bile acids from the above experiments, we will apply hepatocyte transplantation inthis model to achieve long-term repopulation and functional correction of the disease.To expand the sources of donor cells, we will use fetal hepatoblasts at mid- andlate- gestation age in primary cultures. We’ll test the expressions of bile-flow relatedtransporters in the fetal hepatocytes, and test the hypothesis that bile acid signalingregulates the differentiation of fetal hepatoblasts. The unfractionated fetal hepatoblastsor differentiated hepatoblasts could be further applied for cell therapy.The results of this study will have important insight for further clinical celltherapy for inherited or acquired liver diseases; as well as expanding our knowledgeregarding the interactions of bile acid metabolism and hepatocyte development. Theresults will have important impact in further cell therapy such as stem cell therapy orgene therapy for liver diseases.