Project description:Insulin injection is currently the main therapy for type 1 diabetes (T1D) or late stage of severe type 2 diabetes (T2D). Human pancreatic islet transplantation confers a significant improvement in glycemic control and prevents life-threatening severe hypoglycemia in T1D patients. However, the shortage of cadaveric human islets limits their therapeutic potential. In addition, chronic immunosuppression, which is required to avoid rejection of transplanted islets, is associated with severe complications, such as an increased risk of malignancies and infections. Thus, there is a significant need for novel approaches to the large-scale generation of functional human islets protected from autoimmune rejection in order to ensure durable graft acceptance without immunosuppression. An important step in addressing this need is to strengthen our understanding of transplant immune tolerance mechanisms for both graft rejection and autoimmune rejection. Engineering of functional human pancreatic islets that can avoid attacks from host immune cells would provide an alternative safe resource for transplantation therapy. Human pluripotent stem cells (hPSCs) offer a potentially limitless supply of cells because of their self-renewal ability and pluripotency. Therefore, studying immune tolerance induction in hPSC-derived human pancreatic islets will directly contribute toward the goal of generating a functional cure for insulin-dependent diabetes. In this review, we will discuss the current progress in the immune protection of stem cell-derived islet cell therapy for treating diabetes.
Project description:Islet cell transplantation is curative therapy for patients with complicated autoimmune type 1 diabetes (T1D). We report the diagnostic potential of circulating transplant islet-specific exosomes to noninvasively distinguish pancreatic β cell injury secondary to recurrent autoimmunity vs immunologic rejection. A T1D patient with hypoglycemic unawareness underwent islet transplantation and maintained normoglycemia until posttransplant day 1098 before requiring exogenous insulin. Plasma analysis showed decreased donor islet exosome quantities on day 1001, before hyperglycemia onset. This drop in islet exosome quantity signified islet injury, but did not distinguish injury type. However, analysis of purified transplant islet exosome cargoes showed decrease in insulin-containing exosomes, but not glucagon-containing exosomes, indicating selective destruction of transplanted β cells secondary to recurrent T1D autoimmunity. Furthermore, donor islet exosome cargo analysis showed time-specific increase in islet autoantigen, glutamic acid decarboxylase 65 (GAD65), implicated in T1D autoimmunity. Time-matched analysis of plasma transplant islet exosomes in 3 control subjects undergoing islet cell transplantation failed to show changes in islet exosome quantities or intraexosomal cargo expression of insulin, glucagon, and GAD65. This is the first report of noninvasive diagnosis of recurrent autoimmunity after islet cell transplantation, suggesting that transplant tissue exosome platform may serve as a biomarker in islet transplant diagnostics.
Project description:BackgroundIslet cell transplantation holds a potential cure for type 1 diabetes, but many islet recipients do not reach long-lasting insulin independence. In this exploratory study, we investigated whether serum cytokines, chemokines and adipokines are associated with the clinical outcome of islet transplantation.MethodsThirteen islet transplant patients were selected on basis of good graft function (reaching insulin independence) or insufficient engraftment (insulin requiring) from our cohort receiving standardized grafts and immune suppressive therapy. Patients reaching insulin independence were divided in those with continued (>12 months) versus transient (<6 months) insulin independence. A panel of 94 proteins including cytokines and adipokines was measured in sera taken before and at one year after transplantation using a validated multiplex immunoassay platform.ResultsNinety serum proteins were detectable in concentrations varying markedly among patients at either time point. Thirteen markers changed after transplantation, while another seven markers changed in a clinical subpopulation. All other markers remained unaffected after transplantation under generalized immunosuppression. Patterns of cytokines could distinguish good graft function from insufficient function including IFN-α, LIF, SCF and IL-1RII before and after transplantation, by IL-16, CCL3, BDNF and M-CSF only before and by IL-22, IL-33, KIM-1, S100A12 and sCD14 after transplantation. Three other proteins (Leptin, Cathepsin L and S100A12) associated with loss of temporary graft function before or after transplantation.ConclusionsDistinct cytokine signatures could be identified in serum that predict or associate with clinical outcome. These serum markers may help guiding patient selection and choice of immunotherapy, or act as novel drug targets in islet transplantation.
Project description:BackgroundLymphedema is a chronic, debilitating and incurable disease that affects 0.13%-2% of the global population. Emerging evidence indicates that adipose-derived stem cells (ADSCs) might serve as suitable seed cells for lymphatic tissue engineering and lymphedema therapy.AimTo summarize applications of ADSCs for treating lymphedema in both animal studies and clinical trials.MethodsA systematic search was performed on four databases - PubMed, Clinicaltrials.gov, the evidence-based Cochrane Library, and OVID - using the following search string: ("lymphedema" or "lymphoedema" or "lymphangiogenesis") and ("adipose-derived stem cells" or "adipose-derived stromal cells" or "adipose-derived regenerative cells"). A manual search was performed by skimming the references of relevant studies. Animal studies and clinical trials using adipose-derived cells for the treatment of any kind of lymphedema were included.ResultsA total of eight research articles published before November 2019 were included for this analysis. Five articles focused on animal studies and another three focused on clinical trials. ADSC transplantation therapy was demonstrated to be effective against lymphedema in all studies. The animal studies found that coadministration of ADSCs and controlled-release vascular endothelial growth factor-C or platelet-rich plasma could improve the effectiveness of ADSC therapy. Three sequential clinical trials were conducted on breast cancer-related lymphedema patients, and all showed favorable results.ConclusionADSC-based therapy is a promising option for treating lymphedema. Large-scale, multicenter randomized controlled trials are needed to develop more effective and durable therapeutic strategies.
Project description:We are living exciting times in the field of beta cell replacement therapies for the treatment of diabetes. While steady progress has been recorded thus far in clinical islet transplantation, novel approaches are needed to make cell-based therapies more reproducible and leading to long-lasting success. The multiple facets of diabetes impose the need for a transdisciplinary approach to attain this goal, by targeting immunity, promoting engraftment and sustained functional potency. We discuss herein the emerging technologies applied to this rapidly evolving field.
Project description:Improved models of experimental diabetes are needed to develop cell therapies for diabetes. Here, we introduce the B6 RIP-DTR mouse, a model of experimental diabetes in fully immunocompetent animals. These inbred mice harbor the H2b major histocompatibility complex (MHC), selectively express high affinity human diphtheria toxin receptor (DTR) in islet β-cells, and are homozygous for the Ptprca (CD45.1) allele rather than wild-type Ptprcb (CD45.2). 100% of B6 RIP-DTR mice rapidly became diabetic after a single dose of diphtheria toxin, and this was reversed indefinitely after transplantation with islets from congenic C57BL/6 mice. By contrast, MHC-mismatched islets were rapidly rejected, and this allotransplant response was readily monitored via blood glucose and graft histology. In peripheral blood of B6 RIP-DTR with mixed hematopoietic chimerism, CD45.2 BALB/c donor blood immune cells were readily distinguished from host CD45.1 cells by flow cytometry. Reliable diabetes induction and other properties in B6 RIP-DTR mice provide an important new tool to advance transplant-based studies of islet replacement and immunomodulation to treat diabetes.
Project description:Restoration of insulin independence and normoglycemia has been the overarching goal in diabetes research and therapy. While whole-organ and islet transplantation have become gold-standard procedures in achieving glucose control in diabetic patients, the profound lack of suitable donor tissues severely hampers the broad application of these therapies. Here, we describe current efforts aimed at generating a sustainable source of functional human stem cell-derived insulin-producing islet cells for cell transplantation and present state-of-the-art efforts to protect such cells via immune modulation and encapsulation strategies.
Project description:RATIONALE: Peripheral stem cell transplantation may be able to replace immune cells that were destroyed by chemotherapy and radiation therapy used to kill tumor cells.
PURPOSE: Phase I trial to study the effectiveness of treated donor stem cell transplantation in treating patients who have hematologic cancer.
Project description:Since the late 20th century, advances in pancreatic islet transplantation have targeted improved glycemic control and fewer hypoglycemic events in patients with type 1 diabetes, and some important milestones have been reached. Following the Edmonton group's success in achieving insulin independence in all transplanted patients with type 1 diabetes, clinical islet transplantation is now performed worldwide. β cell replacement therapy for type 1 diabetes was established based on the favorable outcomes of a phase 3, prospective, open-label, single-arm, clinical study conducted at 8 centers in North America, in which 42 of 48 patients who underwent islet transplantation from 2008 to 2011 achieved HbA1c < 7.0% (53 mmol/mol) at day 365, which was maintained at 2 years in 34 patients. In Japan, a phase 2 multicenter clinical trial of islet transplantation for type 1 diabetes patients is currently ongoing and will end soon, but the interim results have already led to positive changes, with allogeneic islet transplantation being covered by the national health insurance system since April 2020. Current efforts are being made to solve the problem of donor shortage by studying alternative donor sources, such as porcine islets and pancreatic progenitor cells derived from pluripotent stem cells. The results of clinical trials in this area are eagerly awaited. It is hoped that they will contribute to establishing alternative sources for insulin-producing β cells in the near future.
Project description:Overcoming the immune response to establish durable immune tolerance in type 1 diabetes remains a substantial challenge. The ongoing effector immune response involves numerous immune cell types but is ultimately orchestrated and sustained by the hematopoietic stem cell (HSC) niche. We therefore hypothesized that tolerance induction also requires these pluripotent precursors. In this study, we determined that the tolerance-inducing agent anti-CD45RB induces HSC mobilization in nonautoimmune B6 mice but not in diabetes-prone NOD mice. Ablation of HSCs impaired tolerance to allogeneic islet transplants in B6 recipients. Mobilization of HSCs resulted in part from decreasing osteoblast expression of HSC retention factors. Furthermore, HSC mobilization required a functioning sympathetic nervous system; sympathectomy prevented HSC mobilization and completely abrogated tolerance induction. NOD HSCs were held in their niche by excess expression of CXCR4, which, when blocked, led to HSC mobilization and prolonged islet allograft survival. Overall, these findings indicate that the HSC compartment plays an underrecognized role in the establishment and maintenance of immune tolerance, and this role is disrupted in diabetes-prone NOD mice. Understanding the stem cell response to immune therapies in ongoing human clinical studies may help identify and maximize the effect of immune interventions for type 1 diabetes.