- 學位論文
犬糖尿病誘發及糖尿病奈米磷酸鈣包覆胰島細胞
Canine Diabetes Induction and Nanocapsulated Islet Cell
摘要
糖尿病Ι型約佔全世界所有糖尿病患者的10%( Tilley et al 2006)，而其特點為胰島素的缺乏。使用胰島素注射來控制血糖在這些患者的治療是有效的，但胰島素注射並無法避免因高血糖而引起的眼睛、腎臟、神經和心血管的併發症。 胰島包覆法是一種可以提供抗免疫反應的方法，無論是在同種移植或異種移植(McDonald et al 1987)。因此當胰島移植成為糖尿病Ι型的治療選項時，一些分離、純化、冷凍保存的方法就被研發出，而冷藏保存的流程也已經建立了一個有用的長期保存方法，可使胰島的貯存更有效(Wojtusciszyn et al 2005)。更甚，我們可以提供新鮮分離或者培養的胰島來增加β細胞的總量而達到在移植後增進胰島功能的目的(Oh et al 2005; Witkowski et al 2005)。 胰島移植是一個可信賴控制糖尿病患者血糖的方法但目前還是有一些困難阻礙胰島移植成為一般的臨床治療方法。微米包覆法是一種以機械方法保護胰島組織免受免疫反應抑制的屏障，這個方法甚至可以允許動物組織間的異種移植,以解決組織來源缺乏的問題。微米包覆法目前仍未被廣泛的使用在臨床上,主要是因為胰島細胞在被包覆後存活的時間是有限的，觀察發現胰島細胞在移植後逐漸減少功能，並增加中心區的壞死。同時過量的增值會產生缺氧現象，而生物競爭性、免疫保護反應以及缺氧，這三個重點可能與胰島的逐漸死亡有關(Garfinkel et al 2007)。 本實驗主要是探討犬糖尿病誘發之方法及以奈米材質磷酸鈣骨泥包覆胰島細胞來觀察是否能決絕微小包覆所無法克服之障礙。實驗中我們也同時比較四種不同的糖尿病誘導方法來了解不同方法的優缺點，結果顯示以alloxon 80mg/kg I.V.注射法的成功率最高同時安全性也最好。在誘發成為糖尿病後以磷酸鈣骨泥(calcium phosphate cement, CPC)保護insulinoma cells再移植至股骨的骨髓腔中來控制血糖，在成功移植的四個案例中都有明顯降血糖的效果，但是其持久性則有明顯的個體差異。
並列摘要
Diabetes mellitus(DM) type 1 accounts for approximately 10% of all diabetic cases worldwide and is characterized by an absolute insulin deficiency. Insulin injection therapy as a treatment for type 1 diabetic patient is lifesaving, but it cannot avoid the development of complications of the eyes、 kidney、nerve and the cardiaovascular system. Microencapsulation of isolated islets is a good method for providing protection against immunologic reactions to the cells in both allogeneic and xenogenic. Since islet transplantation has become an option for the treatment of typeΙinsulin-dependent DM, several methods of isolation, purification and cryopreservation of islets of Langerhans have been developed. Cryopreservation procedures have been established as a useful long-term storage strategy. Moreover, they can be used to supplement fresh isolated and/or cultured islets to increase the β-cell mass in order to improve islet graft function following transplantation. Islet transplantation is a promising method of providing tight glycemic control for patient with DM. However ,a number of obstacles currently prevent islet transplantation from becoming routine clinical reality. Microencapsulation is a technique that enables the transplantation of pancreatic islets in the absence of immunosuppression by protecting the islet tissue through a mechanical barrier. This protection may even allow for the transplantation of animal tissue, which opens the perspective of using animal donors as a means to solve the problem of organ shortage. Microencapsulation is not yet applied in clinical practice, mainly because encapsulated islet graft survival is limited. One important observation showed that there is a gradual decrease in islet function, a gradual increase in central necrosis, a continuous increased replication of islet cells, and a nonprogressive overgrowth of a portion of the microencapsulated islet graft. Three important aspects of the microencapsulated islet graft technique may be associated with these phenomena. The first is related to the biocompatibility of the graft. A number of microcapsules lack biocompatibility, which explains the occurrence of overgrowth. The second is related to the immunoprotective properties of the microcapsules. Immunoprotection is incomplete because capsules may allow the passage of small proinflammatory factors, which lead to cell death and dysfunction. The third factor is related to the great distance between the encapsulated islets and the blood supply. An important consequence of the great diffusion distance is the limited supply of oxygen, which leads to hypoxia, causes islet dysfunction and necrosis. In this experiment we compare four methods that could induce diabetes and use nano-material as the barrier that we hope reserving those advantages and resolve some obstacles in microencapsulated graft. Alloxon 80mg/kg I.V. was the best way in induction success rate and patients safty in dogs in this experiment. After the dogs were induced to be diabetes that we implanted calcium phosphate cement(CPC) packaged Insulinoma cells chambers to control the patient’s blood glucose level and make it obviously improved and watching the persistence of function.