胰岛细胞与骨髓间充质干细胞联合移植治疗糖尿病的进展

目的总结胰岛细胞与骨髓间充质干细胞联合移植治疗糖尿病的可行性与安全性。方法收集国内外有关胰岛细胞与骨髓间充质干细胞移植治疗糖尿病的文献并作综述。结果目前糖尿病的治疗方法主要为胰腺移植和胰岛细胞移植,其中胰腺移植的手术创伤大、死亡率高;胰岛细胞移植虽安全性较高,但排斥反应强,胰岛细胞在体内的长期存活时间不理想,严重影响其远期疗效。骨髓间充质干细胞与胰岛细胞联合移植能缓解排斥反应,延长胰岛细胞的存活时间,可以更有效地治疗糖尿病。结论胰岛细胞与骨髓间充质干细胞联合移植具有降低排斥反应、减轻炎症反应、延长胰岛细胞的存活时间及延长降血糖时间的效果,可能是新的治疗糖尿病的手段。     

胰岛细胞移植的研究进展

糖尿病是一种严重危害人类身体健康和生活质量的全球性常见病,针对1型和部分2型糖尿病患者,胰岛移植将是比较彻底的治疗方法.本研究对包括胰岛细胞移植的分类,胰岛移植物的制备、保存及鉴定,移植部位的选择,免疫排斥机制,基因技术的应用及临床病例治疗技术等方面详细阐述了胰岛细胞移植目前的研究现状.随着分子生物学技术和相关学科迅速发展,细胞混合培养,转基因技术,β细胞株的建立,异源性胰岛细胞移植等一系列方法兴起,胰岛移植必将给彻底治愈1型糖尿病带来新的前景.     

胎肝胰岛细胞联合移植治疗糖尿病大鼠

目的探讨胎肝胰岛细胞联合移植治疗糖尿病大鼠的效果,以及胎肝细胞移植诱导糖尿病受者鼠免疫耐受的可行性.方法建立SD大鼠糖尿病模型,将实验动物随机分为正常对照组、糖尿病对照组、胰岛细胞组及肝细胞胰岛细胞联合移植组.将SD胎鼠的胰岛细胞移植于受者浆膜下,观察受者鼠的糖尿病病情变化及免疫状态.结果移植后58.8%(20/34)动物糖尿病得到缓解.联合移植组移植胰岛细胞存活期较胰岛细胞组明显延长(P<0.01);移植后1周,联合移植组血清胰岛细胞肽水平明显高于胰岛细胞组和糖尿病对照组(P＜0.01);脾细胞产生白细胞介素2(IL-2)的活性联合移植组显著低于胰岛细胞组(P＜0.001).结论胃浆膜下是大鼠胰岛移植较理想的移植部位;肝细胞移植可以明显延长移植胰岛细胞的功能存活期,并诱导受者产生特异性免疫耐受和非特异性免疫抑制.     

胰腺干细胞研究进展

糖尿病是严重危害人类健康的重大疾病之一,发病率愈来愈高,预计2025年全球将有3亿患者。目前对于糖尿病的治疗尤其对于1型糖尿病,仍然以胰岛素替代治疗为主,研究表明,胰岛素替代治疗不能改善远期并发的症的发生率,而且存在需要终身治疗、花费昂贵、治疗痛苦等诸多弊端。自1974年Lacy等证实胰岛移植能纠正糖尿病大鼠的高血糖以来,胰岛细胞移植作为目前1型糖尿病治疗最有前景的方法之一已经取得重要进展,到90年代,已有胰岛移植治疗人糖尿病取得成功的报道。但胰岛来源的严重不足限制了其临床应用,近些年来,胰腺干细胞的研究成为新的热点,研究者们试图利用干细胞具有胰岛细胞分化潜能的特点,来从干细胞途径获取足量的胰岛细胞,并且已经有成体胰腺干细胞来源的胰岛细胞移植治疗动物高血糖模型成功的报道。     

胰岛细胞移植物活体成像技术研究的新进展

胰岛细胞移植作为一种新的糖尿病治疗方法，给1型糖尿病患者带来了福音，可以使患者获得胰岛素独立和近似正常的血糖水平，不再增加低血糖的发生率。在过去的数10年里，对胰岛移植虽然作了大量的基础和临床研究，但在20世纪90年代以前，胰岛移植的总体成功率不足10％，90年代后期的近10年里，胰岛移植取得了巨大的进步，特别是2000年Emonton疗法被报道以后。糖尿病的治疗需要进行多次大量的胰岛细胞移植，有学者研究表明，     

胰岛移植治疗1型糖尿病的现状和未来

1型糖尿病是一种全球性的慢性自身免疫疾病,会造成机体一系列代谢紊乱综合征,严重危害人类健康。胰岛移植可以通过增加1型糖尿病患者体内胰岛细胞的数量,减少患者对外源性胰岛素的依赖、有效控制血糖以及防治长期并发症,是一种安全可靠的治疗方法,这都是外源性胰岛素治疗和移植风险极高的全胰腺移植无法实现的。本文就胰岛移植供受体选择、胰岛细胞的分离纯化及胰岛移植、胰岛移植后的免疫抑制治疗、胰岛移植后的监测指标、胰岛移植临床应用的现状以及面临的挑战做一综述。     

胰岛细胞移植前预处理的研究进展

在移植前预先对移植胰岛细胞进行技术处理,可以降低免疫原性,增强胰岛细胞功能,从而使胰岛细胞移植真正成为有效控制血糖代谢、减少和改善糖尿病并发症、进而达到根治糖尿病的治疗手段。     

脂肪间充质干细胞移植治疗1型糖尿病

1型糖尿病严重威胁人类健康,胰岛细胞移植可为机体提供正常的胰岛组织细胞,替代体内已被疾病破坏的胰岛细胞,从而维持正常的血糖水平,达到阻止或延缓并发症的发生,为胰岛素依赖的糖尿病带来新的治疗方案。随着干细胞研究的深入,间充质干细胞诱导后移植治疗1型糖尿病取得了进一步的发展,当然随着研究的深入发现了许多亟待解决的问题,即便如此,脂肪间充质干细胞诱导后移植为临床治疗1型糖尿病带来了新的希望,并指明了方向。     

胰岛细胞移植前预处理的研究进展

在移植前预先对移植胰岛细胞进行技术处理，可以降低免疫原性，增强胰岛细胞功能，从而使胰岛细胞移植真正成为有效控制血糖代谢、减少和改善糖尿病并发症、进而达到根治糖尿病的治疗手段。     

肝脏星状细胞对同种异体胰岛移植的保护作用

胰岛移植的最终目标是在不需要免疫抑制剂治疗的情况下完全恢复糖代谢并阻止长期糖尿病并发症的发生.当前,胰岛移植后需要持续给予免疫抑制剂预防移植排斥反应,而长期应用免疫抑制剂所引起的严重不良反应限制了胰岛移植在糖尿病患者中的广泛应用[1].如何诱导胰岛移植免疫耐受成为临床胰岛移植研究的方向.通过对肝星状细胞(hepatic stelate cell,HSC)的基础研究发现,活化的HSC可抑制免疫反应,诱导移植免疫耐受,从而对同种异体胰岛移植起保护作用.现就HSC对同种异体胰岛移植的保护作用作一综述.     

Technical aspects of islet preparation and transplantation

The introduction of insulin therapy for the management of diabetes mellitus is arguably the greatest milestone in the history of modern medicine. -cell replacement therapy is the only treatment that reestablishes and maintains long-term physiological normoglycemia. Until recently, successful clinical outcomes of pancreas transplantation for patients with long-standing diabetes were much superior to that of islet transplantation. Significant advances in islet isolation and purification technology, the development of more specific and less diabetogenic immunosuppressants and the prophylactic administration of antiviral agents have rekindled a worldwide interest in islet transplantation. This chapter will review the rationale of islet transplantation and the development of islet isolation and purification. The challenges facing clinical islet transplantation in the twenty-first century will also be introduced.     

Glycemic Stability Through Islet‐After‐Kidney Transplantation Using an Alemtuzumab‐Based Induction Regimen and Long‐Term Triple‐Maintenance Immunosuppression

Pancreatic islet transplantation is performed in a select group of patients with type 1 diabetes mellitus. Immunosuppressive regimens play an important role in long‐term islet function. We aimed to investigate the efficacy of islet transplantation in patients with type 1 diabetes and a previous kidney transplantation using an alemtuzumab‐based induction regimen and triple maintenance immunosuppression. Patients with type 1 diabetes, who had received a kidney transplant previously, were treated with alemtuzumab as induction therapy for their first islet transplantation and basiliximab induction therapy for subsequent islet transplantations. Maintenance immunosuppression consisted of triple immunosuppression (tacrolimus, mycophenolate mofetil, and prednisolone). Thirteen patients (age 50.9 ± 9.2 years, duration of diabetes 35 ± 9 years) received a total of 22 islet transplantations. One‐ and 2‐year insulin independence was 62% and 42%, respectively; graft function was 100% and 92%, respectively. HbA1c dropped from 57.2 ± 13.1 (7.4 ± 1.2%) to 44.5 ± 11.8 mmol/molHb (6.2 ± 0.9%) (p = 0.003) after 2 years. Six of 13 patients suffered from severe hypoglycemia before islet transplantation. After transplantation, severe hypoglycemia was restricted to the only patient who lost graft function. Creatinine clearance was unchanged. Islet‐after‐kidney transplantation in patients with type 1 diabetes using an alemtuzumab‐based induction regimen leads to considerable islet allograft function and improvement in glycemic control.     

Regenerative medicine for pancreatic beta cells

Regenerative medicine involves varying degrees of interaction among many research domains. Regenerative medical therapies based on research into organogenesis and the regeneration of injured or dysfunctional tissue using cell therapy are being developed rapidly. For the treatment of diabetes mellitus (DM), pancreatic transplantation and islet (pancreatic endocrine) cell transplantation are considered to be one form of regenerative medicine to overcome pancreatic tissue dysfunction. Recently, the effective islet cell transplantation Edmonton protocol has been established, ushering in a new era in regenerative therapy for DM. However, unresolved problems remain, including a severe donor shortage and unexpected side effects with the longterm use of some immunosuppressive agents. With continuing advances and the clinical application of fundamental therapy for DM, a pancreatic islet cell transplantation or bioartificial pancreatic transplantation system, consisting of islet (pancreatic endocrine) cell purification, pancreatic cell proliferation techniques, immunoisolative membrane technology, and an appropriate transplantation procedure, will be effective. This paper focuses on applied research on human and/or porcine pancreatic cell purification, embryonic stem cell differentiation, and pancreatic stem cell differentiation into functional insulin-producing cells.     

Successful pregnancy and delivery after simultaneous islet‐kidney transplantation

Allogeneic islet of Langerhans transplantation is a recognized beta‐cell replacement therapy for patients affected by type 1 diabetes mellitus. Type 1 diabetes mellitus is a condition associated with an increased risk of adverse outcomes for pregnant women and fetuses. We report the case of a 29‐year‐old woman with type 1 diabetes mellitus, who underwent successful allogeneic islet transplantation with simultaneous kidney transplantation. She achieved durable insulin independence after 2 islet infusions. Pregnancy was desired and planned 2 years after the last islet infusion. Multidisciplinary monitoring of pregnancy was carried out and the immunosuppressive regimen was adapted. Euglycemia was maintained throughout pregnancy without the need for exogenous insulin. After an uneventful pregnancy, she delivered on term an otherwise healthy male child with imperforate anus that was immediately surgically corrected. In conclusion, allogeneic islet transplantation is a suitable treatment for women of childbearing age with complicated type 1 diabetes mellitus, allowing physiologic glycemic control during pregnancy with a low risk of graft loss. This target can be achieved only by a tight multidisciplinary follow‐up, including immunosuppressive therapy adaptation and adequate diabetes and obstetrical monitoring.     

Inducing tolerance to MHC-matched allogeneic islet grafts in diabetic NOD mice by simultaneous islet and bone marrow transplantation under nonirradiative and nonmyeloablative conditioning therapy

BACKGROUND: Human type 1 diabetes is associated with defects in the hematopoietic stem cells. Simultaneous donor islet and bone marrow transplantation may be an ideal therapeutic approach for inducing tolerance to islet allogeneic antigens and restoring self-tolerance to islet autoimmune antigens. METHODS: Using a nonobese diabetic (NOD) mouse model of human type 1 diabetes, we investigated whether tolerance to MHC-matched allogeneic islet grafts from male nonobese diabetes-resistant (NOR) donors can be induced in female NOD recipients by simultaneous islet and bone marrow transplantation under fludarabine phosphate-based nonmyeloablative and irradiation-free conditioning therapy. Donor-specific chimerism in the peripheral blood of tolerant mice (n=7) was measured by semiquantitative polymerase chain reaction for a male-specific marker (SRY). RESULTS: Donor-specific tolerance to NOR islet grafts was induced in all diabetic NOD mice after simultaneous islet and bone marrow transplantation and treated with fludarabine phosphate, cyclophosphamide, anti-mouse lymphocyte serum, and rapamycin. At 100 days and 200 days after transplantation, the average percentage of male NOR marker in DNA derived from the peripheral blood of NOD recipients that had long-term islet graft survival was over 10%. CONCLUSION: Our data suggest that this approach may induce donor-specific tolerance in clinical islet transplantation and living-related donor solid organ transplantation.     

An Odyssey of Islet Transplantation for Therapy of Type 1 Diabetes

Canadian surgical contributions to the field of islet transplantation have a rich heritage and a promising future. In this article, some seminal Canadian contributions to this field are reviewed, including contributions at the basic research laboratory and translational applications to bedside therapy of type 1 diabetes.     

Islet cell transplantation for the treatment of type 1 diabetes in the USA

Islet cell transplantation (ICTx) is one of the most effective treatments for type 1 diabetes and is less invasive compared to whole organ transplantation. The US has been the leader in the research and clinical applications of ICTx for the last 40 years. ICTx requires complex procedures, including pancreas procurement and preservation; pancreas digestion; islet purification; and transplantation. Even with the dramatic progresses in each of the procedures listed above, there are still challenges to make ICTx the standard therapy. These challenges are: (1) obtaining enough islets from a single donor and (2) preventing graft loss due to allogenic rejection and recurrence of autoimmune islet destruction. A new preservation strategy for pancreata and pancreatic ducts using ET-Kyoto solution as well as a new islet purification method using iodixanol has substantially improved islet yields. Continuous research to improve the efficacy of islet isolation will solve the issue of obtaining enough islets from a single donor. Immunological tolerance is an ideal solution for the issue of rejection and autoimmune recurrence and a regulatory T cell strategy seems promising. Moreover, the SUITO index is a simple and powerful tool to assess engrafted islet mass and is, therefore, useful for evaluating the efficacy of new immunosuppressant strategies. Once ICTx becomes a standard treatment, the donor shortage will become the next challenge. Marginal or living donor islet transplantations could help alleviate this issue; however, bio-artificial islet transplantation with animal islets could be the ultimate solution.     

Amyloid Formation in Human Islets Is Enhanced by Heparin and Inhibited by Heparinase

Islet transplantation is a promising therapy for patients with diabetes, but its long‐term success is limited by many factors, including the formation of islet amyloid deposits. Heparin is employed in clinical islet transplantation to reduce clotting but also promotes fibrillization of amyloidogenic proteins. We hypothesized that heparin treatment of islets during pre‐transplant culture may enhance amyloid formation leading to beta cell loss and graft dysfunction. Heparin promoted the fibrillization of human islet amyloid polypeptide (IAPP) and enhanced its toxicity to INS‐1 beta cells. Heparin increased amyloid deposition in cultured human islets, but surprisingly decreased islet cell apoptosis. Treatment of human islets with heparin prior to transplantation increased the likelihood of graft failure. Removal of islet heparan sulfate glycosaminoglycans, which localize with islet amyloid deposits in type 2 diabetes, by heparinase treatment decreased amyloid deposition and protected against islet cell death. These findings raise the possibility that pretransplant treatment of human islets with heparin could potentiate IAPP aggregation and amyloid formation and may be detrimental to subsequent graft function.     

Polymer scaffolds for pancreatic islet transplantation — Progress and challenges

Pancreatic‐islet transplantation is a safe and noninvasive therapy for type 1 diabetes. However, the currently applied site for transplantation, ie, the liver, is not the optimal site for islet survival. Because the human body has shortcomings in providing an optimal site, artificial transplantation sites have been proposed. Such an artificial site could consist of a polymeric scaffold that mimics the pancreatic microenvironment and supports islet function. Recently, remarkable progress has been made in the technology of engineering scaffolds. The polymer‐islet interactions, the site of implantation, and scaffold prevascularization are critical factors for success or failure of the scaffolds. This article critically reviews these factors while also discussing translation of experimental studies to human application as well as the steps required to create a clinically applicable prevascularized, retrievable scaffold for implantation of insulin‐producing cells for treatment of type 1 diabetes mellitus.     

Current status of islet cell transplantation

Despite substantial advances in islet isolation methods and immunosuppressive protocol, pancreatic islet cell transplantation remains an experimental procedure currently limited to the most severe cases of type 1 diabetes mellitus. The objectives of this treatment are to prevent severe hypoglycemic episodes in patients with hypoglycemia unawareness and to achieve a more physiological metabolic control. Insulin independence and long term-graft function with improvement of quality of life have been obtained in several international islet transplant centers. However, experimental trials of islet transplantation clearly highlighted several obstacles that remain to be overcome before the procedure could be proposed to a much larger patient population. This review provides a brief historical perspective of islet transplantation, islet isolation techniques, the transplant procedure, immunosuppressive therapy, and outlines current challenges and future directions in clinical islet transplantation.