Efforts to prevent and halt autoimmune beta cell destruction

Type 1 diabetes - What's new in prevention and therapeutic strategies?

Type 1 diabetes (T1D) is an autoimmune disorder, and insulin deficiency is the result of b-cell dysfunction. Treatment of type 1 diabetes requires constant parenteral insulin administration, which can be very burdensome for the patient. Meticulous use of insulin therapy does not protect the patient against complications. Hence, the search for other methods of treatment as well as ways of preventing the onset of diabetes has been ongoing for a long time. The main obstacle in the implementation of the prevention task is the need to identify people at risk of developing diabetes before the start of autoimmunity. It seems that primary prevention is still unrealistic at the moment, because we do not know all the factors leading to the activation of autoimmunity processes. Research on the use of late secondary prevention in people who develop glucose tolerance disorders or in the early period after the onset of type 1 diabetes are at the most advanced stage. Gene therapy is another attempt at an alternative treatment and prevention of type 1 diabetes and still requires further research. Recent years have brought a lot of information about the nature of type 1 diabetes and the mechanisms leading to its development. However, it has not yet been established what factors decide about the initiation of autoimmunity and what determines the dynamics of these processes.

How Do We Move Type 1 Diabetes Immunotherapies Forward During the Current COVID-19 Pandemic?

Research-based immunotherapy trials seeking to prevent or reverse a number of autoimmune diseases, including type 1 diabetes, have seen near universal suspension due to the coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Diabetes and hyperglycemia are now appreciated as significant risk factors for COVID-19 morbidity and mortality; however, the vast majority of studies have reported on adults. Recent data in children and adolescents with type 1 diabetes suggest no increased risk of COVID-19. Even with immense appreciation for COVID-19 morbidity and mortality, we believe compelling arguments exist to carefully and thoughtfully resume certain type 1 diabetes phase 2-3 immunotherapy trials. In this Perspective, we consider the experience of trials that never halted or have resumed in the oncology and rheumatology fields, and advocate for staged type 1 diabetes immunotherapy trial resumption. With this, we present recommendations to achieve equipoise and mitigate risks for SARS-CoV-2 infection in the weeks surrounding infusion. Given the fact that the COVID-19 pandemic is expected to persist for some time, it is in the best interest of our patients that we find ways to safely move our field forward.

Breakdown in peripheral tolerance in type 1 diabetes in mice and humans

Type 1 Diabetes (T1D), also called juvenile diabetes because of its classically early onset, is considered an autoimmune disease targeting the insulin-producing β cells in the pancreatic islets of Langerhans. T1D reflects a loss of tolerance to tissue self-antigens caused by defects in both central tolerance, which aims at eliminating potentially autoreactive lymphocytes developing in the thymus, and peripheral tolerance, which normally controls autoreactive T cells that escaped the thymus. Like in other autoimmune diseases, the mechanisms leading to T1D are multifactorial and depend on a complex combination of genetic, epigenetic, molecular, and cellular elements that result in the breakdown of peripheral tolerance. In this article, we discuss the contribution of these factors in the development of the autoimmune response targeting pancreatic islets in T1D and the therapeutic strategies currently being explored to correct these defects.

Update on global intervention studies in type 1 diabetes

Remarkable progress has been made in strategies to arrest pancreatic β-cell destruction in type 1 diabetes. Although knowledge of the disease has increased, a safe therapeutic intervention to reverse or prevent it remains elusive. The interaction of genes, immune system, and environment result in a complex disease process that has delayed hopes for a cure. Several well-designed prevention and intervention studies have aspired to test potentially efficacious and safe therapies. This article updates the principles used to design prevention and intervention trials, reviews clinical trials, addresses controversial issues, and provides a framework for future efforts to interdict this condition.

Roles of hydrogen sulfide in the pathogenesis of diabetes mellitus and its complications

SIGNIFICANCE

Diabetes and its complications represent a major socioeconomic problem.

RECENT ADVANCES

Changes in the balance of hydrogen sulfide (H(2)S) play an important role in the pathogenesis of β-cell dysfunction that occurs in response to type 1 and type 2 diabetes. In addition, changes in H(2)S homeostasis also play a role in the pathogenesis of endothelial injury, which develop on the basis of chronically or intermittently elevated circulating glucose levels in diabetes.

CRITICAL ISSUES

In the first part of this review, experimental evidence is summarized implicating H(2)S overproduction as a causative factor in the pathogenesis of β-cell death in diabetes. In the second part of our review, experimental evidence is presented supporting the role of H(2)S deficiency (as a result of increased H(2)S consumption by hyperglycemic cells) in the pathogenesis of diabetic endothelial dysfunction, diabetic nephropathy, and cardiomyopathy.

FUTURE DIRECTIONS

In the final section of the review, future research directions and potential experimental therapeutic approaches around the pharmacological modulation of H(2)S homeostasis in diabetes are discussed.

Protective role of anti-idiotypic antibodies in autoimmunity--lessons for type 1 diabetes

Circulating autoantibodies to beta cell antigens are present in the majority of patients with Type 1 diabetes. These autoantibodies can be detected before and at time of clinical diagnosis of disease. Although the role of autoantibodies in the pathogenesis of the disease is debated, their presence indicates a dysregulation of the humoral immune response. Mechanisms regulating autoantibodies in Type 1 diabetes are not well understood. In contrast, in other autoimmune diseases there is acceptance that autoantibodies are regulated not only by antigen but also by other antibodies that bind to the antigen-binding site of these autoantibodies (anti-idiotypic antibodies). The proposed purpose of this network is to maintain an equilibrium between autoantibodies and their anti-idiotypic antibodies, preventing autoimmunity, while allowing a robust response to exogenous antigen. Anti-idiotypic antibodies regulate both autoantibody binding and their levels by a) neutralizing autoantibodies, and b) inhibiting the secretion of autoantibodies. Because it has been proposed that the B lymphocytes that produce autoantibodies function as autoantigen presenting cells, inhibiting their binding to autoantigen by anti-idiotypic antibodies may prevent development of autoimmune disease. This hypothesis is supported by the presence of anti-idiotypic antibodies in healthy individuals and in patients in remission from autoimmune diseases, and by the lack of anti-idiotypic antibodies during active disease. We recently reported the presence of autoantibodies to glutamate decarboxylase in the majority of healthy individuals, where their binding to autoantigen is prevented by anti-idiotypic antibodies. These anti-idiotypic antibodies are absent at clinical diagnosis of Type 1 diabetes, revealing the presence of autoantibodies. Type 1 diabetes (T1D) is an autoimmune disease characterized by the dysfunction and destruction of insulin-producing beta cells by autoreactive T cells. Although much progress has been made towards understanding the respective roles of effector and regulatory T cells in this beta cell destruction, the development of autoantibodies to beta cell proteins is widely considered simply a by-product of the autoimmune destruction of the beta cells, rather than having an active role in the pathogenesis. This view is starting to change based on increasing recognition that autoantibodies can have defined roles in other autoimmune diseases, and the emergence of new data on their role in T1D. This exploration of the role of autoantibodies in autoimmune disease has been spurred, in part, by increasing recognition that development of autoimmune diseases is influenced by regulatory antibodies (anti-idiotypic antibodies) directed against the unique binding site of autoantibodies. This review provides an overview of the development and function of these anti-idiotypic antibodies, and present evidence supporting their role in the development of autoimmune diseases. Finally, we conclude this review with a model of the events that may cause loss of anti-idiotypic antibodies and the implications for the development of T1D.

New hope for type 2 diabetics: targeting insulin resistance through the immune modulation of stem cells

The prevalence of type 2 diabetes (T2D) is increasing worldwide, highlighting the need for a better understanding of the pathogenesis of the disease and the development of innovative therapeutic approaches for the prevention and cure of the condition. Mounting evidence points to the involvement of immune dysfunction in insulin resistance in T2D, suggesting that immune modulation may be a useful tool in treating the disease. Recent advances in the use of adult stem cells from human umbilical cord blood and bone marrow for immune modulation hold promise for overcoming immune dysfunction in T2D without many of the complications associated with traditional immunosuppressive therapies. This review focuses on recent progress in the use of immune modulation in T2D and discusses the potential for future therapies. New insights are provided on the use of cord blood-derived multipotent stem cells (CB-SC) in T2D.

Critical co-stimulatory pathways in the stability of Foxp3+ Treg cell homeostasis in Type I diabetes

Mechanisms of peripheral tolerance maintain a controlled balance between self-tolerance, protective immunity against a spectrum of non-self antigens, and suppressing pathology in various disorders. CD4(+) regulatory T cells (T(reg)) expressing the Foxp3 transcription factor dominantly control the activity and pathological consequences of a variety of effector T cell lineages in various inflammatory settings. This review will focus on recent advances on the roles of B7 family members in regulating Treg cell development, function and homeostasis during tolerance induction and organ-specific autoimmunity.

Recurrence of autoimmunity in pancreas transplant patients: research update

Type 1 diabetes is an autoimmune disorder leading to loss of pancreatic β-cells and insulin secretion, followed by insulin dependence. Islet and whole pancreas transplantation restore insulin secretion. Pancreas transplantation is often performed together with a kidney transplant in patients with end-stage renal disease. With improved immunosuppression, immunological failures of whole pancreas grafts have become less frequent and are usually categorized as chronic rejection. However, growing evidence indicates that chronic islet autoimmunity may eventually lead to recurrent diabetes, despite immunosuppression to prevent rejection. Thus, islet autoimmunity should be included in the diagnostic work-up of graft failure and ideally should be routinely assessed pretransplant and on follow-up in Type 1 diabetes recipients of pancreas and islet cell transplants. There is a need to develop new treatment regimens that can control autoimmunity, as this may not be effectively suppressed by conventional immunosuppression.