The rise, fall, and resurgence of immunotherapy in type 1 diabetes. Pharmacol Res. 2015;98:31-38. [PMID: 25107501 DOI: 10.1016/j.phrs.2014.07.004]

EXTOD-Immune: a randomised controlled trial to investigate whether a remotely monitored, home-based exercise intervention can reduce disease activity in people with type 1 diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease in which the adaptive immune system targets insulin-producing β-cells of pancreatic islets, leading to dependence on exogenous insulin therapy. Cytotoxic (CD8+) T-cells specific for islet antigens are major players in T1D autoimmunity. Data indicate that regular exercise may preserve β-cell function in people recently diagnosed with T1D, but the role of islet-reactive CD8+ T-cells is unclear. In a randomised crossover design, this study will determine the impact of a 12-week exercise programme on the frequency and proliferative state of islet-reactive CD8+ T-cells in the peripheral blood of 20 adults diagnosed with T1D within the past 3 years. The exercise intervention will consist of three high-intensity interval training sessions per week (6-10 1 min intervals >80% maximum heart rate, with 1 min rest), the duration of which will incrementally increase from 14 to 22 min. Habitual physical activity and diet will be maintained during control and washout periods. At weeks 0, 12, 24 and 36, a fasting blood sample will be collected to quantify the frequency, phenotype and proliferative activity of islet-reactive CD8+ T-cells (primary outcome) and various clinical parameters. Glycaemic control will also be evaluated using 14-day continuous glucose monitoring at the start and end of each study arm. Findings may provide a rationale for conducting large-scale trials to evaluate the implementation of exercise into routine clinical care, particularly for people recently diagnosed with T1D when maintenance of β-cell function is critical to counteract disease progression. Trial registration number: ISRCTN79006041.

Early lung diffusion abnormalities and airways' inflammation in children with type 1 diabetes

BACKGROUND AND AIMS OF THE STUDY

Type 1 diabetes (T1D) impacts lung function and exercise capacity in adults, but limited information is available in children. We hypothesize that T1D causes alterations in pulmonary function and cardiorespiratory fitness, i.e., exercise capacity, at early stages of the disease, due to the presence of inflammation and vascular damage. Therefore, we aim to investigate pulmonary function before and after exercise in children with T1D as compared to age matched healthy controls.

METHOD

Twenty-four children with T1D and twenty healthy controls underwent body plethysmography, diffusion lung capacity for carbon monoxide and fractional exhaled nitric oxide at rest and after cardio-pulmonary exercise test.

RESULTS

In children with T1D, baseline total lung capacity and diffusion lung capacity for carbon monoxide were reduced as compared to healthy controls. Children with T1D also showed a reduced exercise capacity associated with poor aerobic fitness. Accordingly, diffusion lung capacity for carbon monoxide tended to increase with exercise in healthy controls, while no change was observed in children with T1D. Fractional exhaled nitric oxide was significantly higher at baseline and tended to increase with exercise in children with T1D, while no changes were observed in healthy controls.

CONCLUSIONS

Altered diffusion lung capacity for carbon monoxide, increased fractional exhaled nitric oxide and a poor aerobic fitness to exercise suggests the presence of early pulmonary abnormalities in children with T1D.

Impact of Living with Stigma in Persons with Type 1 Diabetes: A Patient-Physician Perspective

Type 1 diabetes mellitus (T1D) is an autoimmune disorder characterized by a complete deficiency in insulin due to the destruction of pancreatic beta cells. Globally, T1D accounts for nearly 5-10% of the total diabetes cases. Living with this life-long condition has a significant emotional, psychological, physical, mental, and social impact. Despite extensive research characterizing the underlying physiology of T1D, additional work is needed to address the psychosocial aspects associated with the condition and its effect on the quality of life (QoL) of people living with T1D. One area that warrants further exploration is the stigma-related stereotypes and prejudice of people living with T1D experience in real-life settings. Despite the acknowledgment of stigma for conditions such as obesity, mental illness, and epilepsy, its association with T1D and ensuing psychological distress remains relatively under-investigated. Health-related stigma is a huge barrier to seeking appropriate, timely support for enhanced healthcare management and engagement in such patients. Here, we provide the perspectives of an adult with over 33 years of living with T1D and an expert endocrinologist who details their experience of T1D-related stigma. The self-reported factors explored by the person living with T1D include (but are not limited to) blame, mockery of the condition/person, diabetes-related shame, exclusion, rejection, negative judgments, fear, stereotyping, and discrimination. The lived experience supported by the clinical insights of the endocrinologist highlights the urgent need to decipher the severity, extent, nature, determinants, and consequences of stigma faced by a person living with T1D. Raising societal awareness, increasing education for caregivers, access to counseling for people living with diabetes, and engaging in shared decision-making remain the path forward.

Pharmacologically Enhanced Regulatory Hematopoietic Stem Cells Revert Experimental Autoimmune Diabetes and Mitigate Other Autoimmune Disorders

Type 1 diabetes (T1D) is characterized by the loss of immune self-tolerance, resulting in an aberrant immune responses against self-tissue. A few therapeutics have been partially successful in reverting or slowing down T1D progression in patients, and the infusion of autologous hematopoietic stem cells (HSCs) is emerging as an option to be explored. In this study, we proposed to pharmacologically enhance by ex vivo modulation with small molecules the immunoregulatory and trafficking properties of HSCs to provide a safer and more efficacious treatment option for patients with T1D and other autoimmune disorders. A high-throughput targeted RNA sequencing screening strategy was used to identify a combination of small molecules (16,16-dimethyl PGE₂ and dexamethasone), which significantly upregulate key genes involved in trafficking (e.g., CXCR4) and immunoregulation (e.g., programmed death ligand 1). The pharmacologically enhanced, ex vivo-modulated HSCs (regulatory HSCs [HSC.Regs]) have strong trafficking properties to sites of inflammation in a mouse model of T1D, reverted autoimmune diabetes in NOD mice, and delayed experimental multiple sclerosis and rheumatoid arthritis in preclinical models. Mechanistically, HSC.Regs reduced lymphocytic infiltration of pancreatic β cells and inhibited the activity of autoreactive T cells. Moreover, when tested in clinically relevant in vitro autoimmune assays, HSC.Regs abrogated the autoimmune response. Ex vivo pharmacological modulation enhances the immunoregulatory and trafficking properties of HSCs, thus generating HSC.Regs, which mitigated autoimmune diabetes and other autoimmune disorders.

Chemical composition, antioxidant, and anti-diabetic activities of ethyl acetate fraction of Stachys riederi var. japonica (Miq.) in streptozotocin-induced type 2 diabetic mice

This work analysed the chemical composition, antioxidant, and enzyme inhibitory activities of solvent extract (SJ-ME) and fractions (SJ-HF, SJ-EAF, and SJ-MF) of the Stachys riederi var. japonica (Miq.) (SJ). Furthermore, the effect of SJ-EAF in STZ induced type 2 diabetic mice was examined. Among the samples, SJ-EAF exhibited a lower IC50 concentration of 64.2 ± 0.48 μg/mL for DPPH and 82.6 ± 0.09 μg/mL for ABTS+. The SJ-EAF concentration of 2.89 ± 0.03 μg and 2.27 ± 0.98 μg was equivalent to 1 μg of acarbose mediated enzyme inhibitory effect against α-amylase and α -glucosidase, respectively. The SJ-EAF did not show cytotoxicity (<80%) to NIH3T3 nor HepG2 cells but enhanced the glucose uptake in the IR-HepG2. LC-MS/MS of SJ-EAF showed the presence of a total of 16 compounds. Among the identified compounds, rosmarinic acid, caffeic acid, oleanolic acid, and ursolic acid showed high catalytic activity of α-amylase and α-glucosidase. The treatments of SJ-EAF restored the level of blood glucose, body weight, insulin, HDL and mRNA level of IRS1, GLUT2, GLUT4 and Akt whereas it reduced the excess elevation of total cholesterol, total triglycerides, LDL, AST, ALT, ALP, BUN, and creatinine in STZ induced diabetic mice. Overall, the present study concluded that the SJ-EAF exhibited promising antidiabetic activity.

Cyanidin-3-O-Glucoside improves the viability of human islet cells treated with amylin or Aβ1-42 in vitro

Islet transplantation is being considered as an alternative treatment for type 1 diabetes. Despite recent progress, transplant recipients continue to experience progressive loss of insulin independence. Cyanidin-3-O-Glucoside (C3G) has shown to be protective against damage that may lead to post-transplant islet loss. In this study, human islets cultured with or without C3G were treated with human amylin, Aβ1-42, H2O2, or rapamycin to mimic stresses encountered in the post-transplant environment. Samples of these islets were collected and assayed to determine C3G's effect on cell viability and function, reactive oxygen species (ROS), oxidative stress, amyloid formation, and the presence of inflammatory as well as autophagic markers. C3G treatment of human islets exposed to either amylin or Aβ1-42 increased cell viability (p<0.01) and inhibited amyloid formation (p<0.01). A reduction in ROS and an increase in HO-1 gene expression as well as in vitro islet function were also observed in C3G-treated islets exposed to amylin or Aβ1-42, although not significantly. Additionally, treatment with C3G resulted in a significant reduction in the protein expression of inflammatory markers IL-1β and NLRP3 (p<0.01) as well as an increase in LC3 autophagic marker (p<0.05) in human islets treated with amylin, Aβ1-42, rapamycin, or H2O2. Thus, C3G appears to have a multi-faceted protective effect on human islets in vitro, possibly through its anti-oxidant property and alteration of inflammatory as well as autophagic pathways.

Novel idebenone analogs block Shc's access to insulin receptor to improve insulin sensitivity

There has been little innovation in identifying novel insulin sensitizers. Metformin, developed in the 1920s, is still used first for most Type 2 diabetes patients. Mice with genetic reduction of p52Shc protein have improved insulin sensitivity and glucose tolerance. By high-throughput screening, idebenone was isolated as the first small molecule 'Shc Blocker'. Idebenone blocks p52Shc's access to Insulin Receptor to increase insulin sensitivity. In this work the avidity of 34 novel idebenone analogs and 3 metabolites to bind p52Shc, and to block the interaction of p52Shc with the Insulin receptor was tested. Our hypothesis was that if an idebenone analog bound and blocked p52Shc's access to insulin receptor better than idebenone, it should be a more effective insulin sensitizing agent than idebenone itself. Of 34 analogs tested, only 2 both bound p52Shc more tightly and/or blocked the p52Shc-Insulin Receptor interaction more effectively than idebenone. Of those 2 only idebenone analog #11 was a superior insulin sensitizer to idebenone. Also, the long-lasting insulin-sensitizing potency of idebenone in rodents over many hours had been puzzling, as the parent molecule degrades to metabolites within 1 h. We observed that two of the idebenone's three metabolites are insulin sensitizing almost as potently as idebenone itself, explaining the persistent insulin sensitization of this rapidly metabolized molecule. These results help to identify key SAR = structure-activity relationship requirements for more potent small molecule Shc inhibitors as Shc-targeted insulin sensitizers for type 2 diabetes.

Regular physical activity as a physiological factor contributing to extend partial remission time in children with new onset diabetes mellitus-Two years observation

BACKGROUND

Beneficial effects of physical activity (PA) are confirmed in patients with all types of long-lasting diabetes. The possibility of PA to be a factor prolonging remission phase in children with new-onset type 1 diabetes (T1D) has not yet been thoroughly studied.

OBJECTIVE

The aim of the study was to elucidate the influence of regular PA on prevalence of partial remission (PR), metabolic control, daily insulin requirement (DIR), and C-peptide secretion in children newly diagnosed with T1D.

METHODS

A total of 125 children diagnosed with T1D were studied prospectively for 2 years. Patients were controlled every 3 months and advised with PA according to ISPAD recommendations. Anthropometric parameters, HbA1c, C-peptide level and DIR were analyzed. Patients' PA level was assessed using a self-designed questionnaire.

RESULTS

We classified 43% of participants as physically-active. In this group, lower HbA1c after 2 years, lower DIR after 3, 6 months, and after 2 years (all P < .05) were found. At discharge from hospital, the prevalence of DIR < 0.5 U/kg/24 h with near normoglycemia was similar in both groups. Then, we observed higher PR prevalence in active group lasting over time and resulting in 44% vs 13% after 2 years (P < .001). C-peptide after 2 years was comparable in both groups, with higher prevalence of clinically significant levels (>0.2 nmoL/L) in active group: 79.6% vs 61.4% (P = .029).

CONCLUSIONS

These data support the view that regular PA may essentially contribute to extending PR time in pediatric diabetes, and may therefore lead to a better long-term metabolic control of the disease.

Embryonic stem cell extracts improve wound healing in diabetic mice

AIMS/HYPOTHESIS

Impaired wound healing significantly impacts morbidity and mortality in diabetic patients, necessitating the development of novel treatments to improve the wound healing process. We here investigated the topical use of acellular embryonic stem cell extracts (EXTs) in wound healing in diabetic db/db mice.

METHODS

Wounds were induced in diabetic db/db mice, which were subsequently treated with EXTs, with 3T3 fibroblast cell line protein extracts (3T3XTs) or with saline as a control. Pathology and mechanistic assays were then performed.

RESULTS

The in vivo topical administration of EXTs facilitates wound closure, contraction and re-epithelialization. Moreover, EXTs reduced the number of wound-infiltrating CD45⁺ inflammatory cells and increased the rate of repair and of angiogenesis as compared to controls. Interestingly, the EXT effect was partly enhanced by the use of a collagen-based biocompatible scaffold. In vivo, topical administration of EXTs increased the percentage of regulatory T cells in the wounded tissue, while in vitro EXT treatment reduced T cell-mediated IFN-γ production. Proteomic screening revealed 82 proteins differentially segregating in EXTs as compared to 3T3 extracts, with APEX1 identified as a key player for the observed immunomodulatory effect of EXTs.

CONCLUSIONS

EXTs are endowed with immunoregulatory and anti-inflammatory properties; their use improves wound healing in diabetic preclinical models.

Cell therapy for type 1 diabetes

INTRODUCTION

Type 1 diabetes (T1D) is a lifelong condition resulting from autoimmune destruction of insulin-producing β-cells. Islet or whole-pancreas transplantation is limited by the shortage of donors and need for chronic immune suppression. Novel strategies are needed to prevent β-cell loss and to rescue production of endogenous insulin.

AREAS COVERED

This review covers the latest advances in cell-based therapies for the treatment and prevention of T1D. Topics include adoptive transfer of cells with increased immunoregulatory potential for β-cell protection, and β-cell replacement strategies such as generation of insulin-producing β-like cells from unlimited sources.

EXPERT OPINION

Cell therapy provides an opportunity to prevent or reverse T1D. Adoptive transfer of autologous cells having enhanced immunomodulatory properties can suppress autoimmunity and preserve β-cells. Such therapies have been made possible by a combination of genome-editing techniques and transplantation of tolerogenic cells. In-vitro modified autologous hematopoietic stem cells and tolerogenic dendritic cells may protect endogenous and newly generated β-cells from a patient's autoimmune response without hampering immune surveillance for infectious agents and malignant cellular transformations. However, methods to generate cells that meet quality and safety standards for clinical applications require further refinement.

Reversal of Hyperglycemia and Suppression of Type 1 Diabetes in the NOD Mouse with Apoptotic DNA Immunotherapy™ (ADi™), ADi-100

The antigen-specific apoptotic DNA immunotherapeutic, ADi-100, is designed to suppress type 1 diabetes and consists of two DNA plasmids encoding genetic sequences of the apoptosis-inducing molecule, BAX, and the secreted form of the autoantigen, glutamic acid decarboxylase 65, that is CpG hyper-methylated to avoid inflammatory signaling (msGAD55). Upon a four-day treatment with ADi-100 of young female non-obese diabetic (NOD) mice, the frequency of various tolerogenic dendritic cell populations increased in draining lymph nodes; these cells lost the capacity to stimulate glutamic acid decarboxylase (GAD)-specific CD4⁺ T lymphocytes and were associated with the previously demonstrated enhancement of GAD-specific regulatory T cells. The efficacy of two ADi-100 formulations containing different proportions of BAX and msGAD55, 1:4 (10/40 µg) and 1:2 (17/33 µg), was evaluated in mildly hyperglycemic pre-diabetic NOD female mice. Both formulations suppressed the incidence of diabetes by 80% in an antigen-specific manner, while all untreated mice developed diabetes. However, treatment of pre-diabetic mice with significantly higher hyperglycemia, denoting progressive disease, showed that ADi-100 1:2 strongly suppressed diabetes incidence by 80% whereas the ADi-100 1:4 was less effective (50%). As an antigen-specific monotherapy, ADi-100 is highly efficacious in reversing elevated hyperglycemia to prevent diabetes, in which increasing apoptosis-inducing BAX content is a promising immune tolerance feature.

Rat Models of Human Type 1 Diabetes

Rat models of human type 1 diabetes have been shown to be of great importance for the elucidation of the mechanisms underlying the development of autoimmune diabetes. The three major well-established spontaneous rat models are the BioBreeding (BB) diabetes-prone rat, the Komeda diabetes-prone (KDP) rat, and the IDDM (LEW.1AR1-iddm) rat. Their distinctive features are described with special reference to their pathology, immunology, and genetics and compared with the situation in patients with type 1 diabetes mellitus. For all three established rat models, a distinctive genetic mutation has been identified that is responsible for the manifestation of the diabetic syndrome in these rat strains.

The multifaceted nature of diabetes mellitus induced by checkpoint inhibitors

Immune checkpoint inhibitors (CPI) are increasingly being used in oncology, and many autoimmune side effects have been described. Diabetes mellitus (DM) has been reported in approximately 1% of subjects treated with programmed cell death-1 and programmed death ligand 1 (PD-1/PD-L1) inhibitors, alone or in association with CTLA-4 inhibitors. In the present mini-review, we aimed to describe different clinical pictures and pathophysiology associated with these forms of diabetes. Data on CPI-related DM was gathered from the largest case series in the literature and from our centre dedicated to immunotherapy complications (ImmuCare-Hospices Civils de Lyon). Most cases are acute autoimmune insulin-dependent diabetes which are similar to fulminant diabetes (extremely acute onset with concomitant near-normal HbA1c levels). Other cases, however, have a phenotype close to type 2 diabetes or appear as a decompensation of previously known type 2 diabetes. The occurrence of diabetes can also be a complication of autoimmune pancreatitis induced by CPI use. Finally, two cases of diabetes in a context of autoimmune lipoatrophy have recently been described. Regarding the wide variety of CPI-induced diabetes, the discovery of a glucose disorder under CPI should motivate specialised care for aetiological diagnosis and appropriate treatment.

Preclinical and clinical results regarding the effects of a plant-based antidiabetic formulation versus well established antidiabetic molecules

Diabetes mellitus (DM) is a complex syndrome with debilitating long-term complications, comprising alterations of carbohydrate, protein and lipid metabolisms, along increased oxidative stress and chronic low-grade inflammation. Diet management and plant-based formulations can improve the metabolic status of patients, being used as adjuvants of classic antidiabetic therapy. The purpose of our study was to evaluate the impact of a plant-based antidiabetic formulation (PBAF), containing Vaccinium myrtillus, Ribes nigrum, Rosa canina and Capsicum annuum, on the increased oxidative burden found in diabetes mellitus, comparing it with the effects of metformin and gliclazide. Firstly, we characterized the individual plant-derived components of this formulation and also assessed their in vitro radical scavenging capacity. We devised a preclinical study protocol to examine the impact of the PBAF, along metformin and gliclazide, on tissue histology as well as on the redox status of tissue, mitochondria, serum and serum lipoproteins of alloxan-induced diabetic Wistar rats. Subsequently, we assessed their long-term impact on the redox status of serum and isolated serum lipoproteins of type 2 DM (T2DM) patients, taking into consideration their cardiometabolic profile. In the preclinical stage, we found that PBAF was able to enhance total serum antioxidant defense, while metformin yielded the best results regarding the advanced glycation and protein/lipid oxidation of serum and of serum lipoproteins. The latter also improved overall serum redox status and HDL redox function. Also, antidiabetic treatment seemed to increase mitochondrial redox activity, without overturning overall tissue redox balance. Histologically, liver and brain tissues of treated diabetic rats were fairly similar to those of non-diabetic rats. In T2DM patients, the most striking results involved the effects on serum lipoproteins. The tested PBAF exerted protective antioxidant effects on low-density and, especially, on high density lipoproteins. We conclude that this formulation might constitute a good addition to the well-established pharmacological approach of DM, contributing to the reduction of overall oxidative burden.

A metabolic perspective of late onset Alzheimer's disease

After decades of research, the molecular neuropathology of Alzheimer's disease (AD) is still one of the hot topics in biomedical sciences. Some studies suggest that soluble amyloid β (Aβ) oligomers act as causative agents in the development of AD and could be initiators of its complex neurodegenerative cascade. On the other hand, there is also evidence pointing to Aβ oligomers as mere aggravators, with an arguable role in the origin of the disease. In this line of research, the relative contribution of soluble Aβ oligomers to neuronal damage associated with metabolic disorders such as Type 2 Diabetes Mellitus (T2DM) and obesity is being actively investigated. Some authors have proposed the endoplasmic reticulum (ER) stress and the induction of the unfolded protein response (UPR) as important mechanisms leading to an increase in Aβ production and the activation of neuroinflammatory processes. Following this line of thought, these mechanisms could also cause cognitive impairment. The present review summarizes the current understanding on the neuropathological role of Aβ associated with metabolic alterations induced by an obesogenic high fat diet (HFD) intake. It is believed that the combination of these two elements has a synergic effect, leading to the impairement of ER and mitochondrial functions, glial reactivity status alteration and inhibition of insulin receptor (IR) signalling. All these metabolic alterations would favour neuronal malfunction and, eventually, neuronal death by apoptosis, hence causing cognitive impairment and laying the foundations for late-onset AD (LOAD). Moreover, since drugs enhancing the activation of cerebral insulin pathway can constitute a suitable strategy for the prevention of AD, we also discuss the scope of therapeutic approaches such as intranasal administration of insulin in clinical trials with AD patients.

Semisynthetic bile acids: a new therapeutic option for metabolic syndrome

Bile acids are endogenous emulsifiers synthesized from cholesterol having a peculiar amphiphilic structure. Appreciation of their beneficial effects on human health, recognized since ancient times, has expanded enormously since the discovery of their role as signaling molecules. Activation of farnesoid X receptor (FXR) and Takeda G-protein receptor-5 (TGR5) signaling pathways by bile acids, regulating glucose, lipid and energy metabolism, have become attractive avenue for metabolic syndrome treatment. Therefore, extensive effort has been directed into the research and synthesis of bile acid derivatives with improved pharmacokinetic properties and high potency and selectivity for these receptors. Minor modifications in the structure of bile acids and their derivatives may result in fine-tuning modulation of their biological functions, and most importantly, in an evasion of undesired effect. A great number of semisynthetic bile acid analogues have been designed and put in preclinical and clinical settings. Obeticholic acid (INT-747) has achieved the biggest clinical success so far being in use for the treatment of primary biliary cholangitis. This review summarizes and critically evaluates the key chemical modifications of bile acids resulting in development of novel semisynthetic derivatives as well as the current status of their preclinical and clinical evaluation in the treatment of metabolic syndrome, an aspect that is so far lacking in the scientific literature. Taking into account the balance between therapeutic benefits and potential adverse effects associated with specific structure and mechanism of action, recommendations for future studies are proposed.

Quercetin inhibited mesangial cell proliferation of early diabetic nephropathy through the Hippo pathway

Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes and the leading cause of end-stage renal disease. The proliferation of glomerular mesangial cells (MCs) is a common and prominent pathological change of DN, which takes place at the early stage. Quercetin, a bioflavonoid compound, possesses therapeutic efficacy in cardiovascular and kidney diseases via anti-tumour, anti-oxidation, anti-virus, and anti-proliferation effects. However, the mechanism of quercetin in the proliferation of glomerular MCs in early DN has not been reported. In the present study, we investigated the effect of quercetin on the proliferation of glomerular MCs in high glucose-induced mouse glomerular MCs and in db/db mice. On this basis, we tried to clarify the specific mechanisms underlying these effects. The in vitro results showed that the proliferation of glomerular MCs was induced by high glucose, and the Hippo pathway was highly inactivated in high glucose-cultured MCs. Decreased phosphorylation of MST1 and Lats1 promoted expression and nuclear translocation of Yes-associated protein (YAP) and subsequently increased the combination of YAP and TEA/ATS domain (TEAD), which promoted the expression of the downstream target gene such as cyclinE. Quercetin effectively inhibited the high glucose-induced MC proliferation and reactivated the Hippo pathway. In vivo, the proliferation of glomerular MCs was increased, renal function was decreased, and blood fasting glucose was elevated in db/db mice. Furthermore, the Hippo pathway was inactivated in the renal cortex of db/db mice. Eight-week treatment of quercetin retarded MC proliferation, alleviated the renal function, and reactivated Hippo pathway in the renal cortex of db/db mice at 16 weeks. Our previous study clarified that the Hippo pathway was involved in MC proliferation of DN. The results revealed that quercetin inhibited MC proliferation in high glucose-treated mouse glomerular MCs and in DN via reactivation of the Hippo pathway.

Combining anti-IL-7Rα antibodies with autoantigen-specific immunotherapy enhances non-specific cytokine production but fails to prevent Type 1 Diabetes

Autoantigen-specific methods to prevent and treat Type 1 Diabetes (T1D) carry high hopes to permanently cure this disease, but have largely failed in clinical trials. One suggested approach to increase the efficacy of islet antigen-specific vaccination is to combine it with a modulator of the T cell response, with the goal of reducing effector differentiation and promoting regulatory T cells (Tregs). Here we asked if addition of antibodies that block the IL-7/IL-7Rα pathway altered the T cell response to islet antigen vaccination and prevented T1D in non-obese diabetic (NOD) mice. Anti-IL-7Rα monoclonal antibodies (mAbs) reduced the numbers of islet antigen-specific T cells generated after vaccination with islet peptides and alum. However, addition of anti-IL-7Rα antibodies to peptide/alum vaccination unexpectedly increased non-specific IFN-γ, IL-2 and IL-10 cytokine production and did not result in improved prevention of T1D onset. In a second approach, we used a conjugate vaccine to deliver islet autoantigens, using Keyhole Limpet Hemocyanin (KLH) as a carrier. Islet antigen-KLH vaccination led to a significant expansion of antigen-specific Tregs and delayed diabetes onset in NOD mice. These outcomes were not further improved by addition of anti-IL-7Rα antibodies. To the contrary, blocking IL-7Rα during vaccination led to non-specific cytokine production and reduced the efficacy of a KLH-conjugated vaccine to prevent T1D. Our study thus revealed that adding anti-IL-7Rα antibodies during autoantigen immunization did not improve the efficacy of such vaccinations to prevent T1D, despite altering some aspects of the T cell response in a potentially advantageous way. Further refinement of this approach will be required to separate the beneficial from the adverse effects of anti-IL-7Rα antibodies to treat autoimmune disease.

Advances in immunotherapy of type I diabetes

Type 1 diabetes mellitus (T1DM) is an autoimmune disease affecting 3 million individuals in the U.S. The pathogenesis of T1DM is driven by immune-mediated destruction of pancreatic β cells, the source of glucose regulator insulin. While T1DM can be successfully managed with insulin replacement therapy, approaches that can modify the underlying immuno-pathology of β cell destruction has been long sought after. Immunotherapy can attenuate T cell responses against β cell antigens. Given the detailed cellular and molecular definitions of T1DM immune responses, rational immunomodulation can be and have been developed in mouse models, and in some instances, tested in humans. The possibility of identifying individuals who are predisposed to T1DM through genotyping lend to the possibility of preventive vaccines. While much has been accomplished in delineating the mechanisms of immunotherapies, some of which are being tested in humans, long-term preservation of β cells and insulin independency has not been achieved. In this regard, the drug delivery field has much to offer in maximizing the benefits of immune modulators by optimizing spatiotemporal presentation of antigens and costimulatory signals. In this review, we attempt to capture the current state of T1DM immunotherapy by highlighting representative studies.

Idebenone is a cytoprotective insulin sensitizer whose mechanism is Shc inhibition

When insulin binds insulin receptor, IRS1 signaling is stimulated to trigger the maximal insulin response. p52Shc protein competes directly with IRS1, thus damping and diverting maximal insulin response. Genetic reduction of p52Shc minimizes competition with IRS1, and improves insulin signaling and glucose control in mice, and improves pathophysiological consequences of hyperglycemia. Given the multiple benefits of Shc reduction in vivo, we investigated whether any of 1680 drugs used in humans may function as Shc inhibitors, and thus potentially serve as novel anti-diabetics. Of the 1680, 30 insulin sensitizers were identified by screening in vitro, and of these 30 we demonstrated that 7 bound Shc protein. Of the 7 drugs, idebenone dose-dependently bound Shc protein in the 50-100 nM range, and induced insulin sensitivity and cytoprotection in this same 100 nM range that clinically dosed idebenone reaches in human plasma. By contrast we observe mitochondrial effects of idebenone in the 5,000 nM range that are not reached in human dosing. Multiple assays of target engagement demonstrate that idebenone physically interacts with Shc protein. Idebenone sensitizes mice to insulin in two different mouse models of prediabetes. Genetic depletion of idebenone's target eliminates idebenone's ability to insulin-sensitize in vivo. Thus, idebenone is the first-in-class member of a novel category of insulin-sensitizing and cytoprotective agents, the Shc inhibitors. Idebenone is an approved drug and could be considered for other indications such as type 2 diabetes and fatty liver disease, in which insulin resistance occurs.

PD-L1 genetic overexpression or pharmacological restoration in hematopoietic stem and progenitor cells reverses autoimmune diabetes

Immunologically based clinical trials performed thus far have failed to cure type 1 diabetes (T1D), in part because these approaches were nonspecific. Because the disease is driven by autoreactive CD4 T cells, which destroy β cells, transplantation of hematopoietic stem and progenitor cells (HSPCs) has been recently offered as a therapy for T1D. Our transcriptomic profiling of HSPCs revealed that these cells are deficient in programmed death ligand 1 (PD-L1), an important immune checkpoint, in the T1D nonobese diabetic (NOD) mouse model. Notably, the immunoregulatory molecule PD-L1 plays a determinant role in controlling/inhibiting activated T cells and thus maintains immune tolerance. Furthermore, our genome-wide and bioinformatic analysis revealed the existence of a network of microRNAs (miRNAs) controlling PD-L1 expression, and silencing one of key altered miRNAs restored PD-L1 expression in HSPCs. We therefore sought to determine whether restoration of this defect would cure T1D as an alternative to immunosuppression. Genetically engineered or pharmacologically modulated HSPCs overexpressing PD-L1 inhibited the autoimmune response in vitro, reverted diabetes in newly hyperglycemic NOD mice in vivo, and homed to the pancreas of hyperglycemic NOD mice. The PD-L1 expression defect was confirmed in human HSPCs in T1D patients as well, and pharmacologically modulated human HSPCs also inhibited the autoimmune response in vitro. Targeting a specific immune checkpoint defect in HSPCs thus may contribute to establishing a cure for T1D.

Simultaneous Recognition of Allogeneic MHC and Cognate Autoantigen by Autoreactive T Cells in Transplant Rejection

The autoimmune condition is a primary obstacle to inducing tolerance in type 1 diabetes patients receiving allogeneic pancreas transplants. It is unknown how autoreactive T cells that recognize self-MHC molecules contribute to MHC-disparate allograft rejection. In this report, we show the presence and accumulation of dual-reactive, that is autoreactive and alloreactive, T cells in C3H islet allografts that were transplanted into autoimmune diabetic NOD mice. Using high-throughput sequencing, we discovered that T cells prevalent in allografts share identical TCRs with autoreactive T cells present in pancreatic islets. T cells expressing TCRs that are enriched in allograft lesions recognized C3H MHC molecules, and five of six cell lines expressing these TCRs were also reactive to NOD islet cells. These results reveal the presence of autoreactive T cells that mediate cross-reactive alloreactivity, and indicate a requirement for regulating such dual-reactive T cells in tissue replacement therapies given to autoimmune individuals.

Interleukin-35 mitigates the function of murine transplanted islet cells via regulation of Treg/Th17 ratio

Pancreatic islet transplantation is a promising treatment for type 1 diabetes (T1D). Interleukin-35 (IL-35) is a recently discovered cytokine that exhibits potent immunosuppressive functions. However, the role of IL-35 in islet transplant rejection remains to be elucidated. In this study, we isolated islet cells of BALB/c mouse and purified CD4+ T cell subsets of a C57BL/6 mouse. The model for islet transplantation was established in vitro by co-culture of the islet cells and CD4+ T cells. IL-35 (20 ng/ml) was administered every other day. Following co-culture, the islet function and Treg/Th17 ratio were analyzed on days 1, 3, and 5. Furthermore, the Th17/Treg ratio was modulated (1:0–2), and the function of islet cells as well as proliferation of Th17 cells were analyzed. T cell sorting was performed using the magnetic bead sorting method; Treg and Th17 count using flow cytometry; cell proliferation detection using the carboxyfluorescein diacetate succinimidyl ester (CFSE) method, and islet function test using the sugar stimulation test. Results showed that Th17 counts increased in the co-culture system. However, after administration of IL-35, the number of Treg cells increased significantly compared to that in the control group (50.7% of total CD4+ T cells on day 5 in IL-35 group vs. 9.5% in control group) whereas the proliferation rate of Th17 cells was significantly inhibited (0.3% in IL-35 group vs. 7.2% in control group on day 5). Reducing the Th17/Treg ratio significantly improved the function of transplanted islets. Treg inhibited Th17 proliferation and IL-35 enhanced this inhibitory effect. IL-35 mitigates the function of murine transplanted islet cells via regulation of the Treg/Th17 ratio. This might serve as a potential therapeutic strategy for in-vivo islet transplant rejection and T1D.

MIF inhibition interferes with the inflammatory and T cell-stimulatory capacity of NOD macrophages and delays autoimmune diabetes onset

Macrophages contribute in the initiation and progression of insulitis during type 1 diabetes (T1D). However, the mechanisms governing their recruitment into the islets as well as the manner of retention and activation are incompletely understood. Here, we investigated a role for macrophage migration inhibitory factor (MIF) and its transmembrane receptor, CD74, in the progression of T1D. Our data indicated elevated MIF concentrations especially in long-standing T1D patients and mice. Additionally, NOD mice featured increased MIF gene expression and CD74+ leukocyte frequencies in the pancreas. We identified F4/80+ macrophages as the main immune cells in the pancreas expressing CD74 and showed that MIF antagonism of NOD macrophages prevented their activation-induced cytokine production. The physiological importance was highlighted by the fact that inhibition of MIF delayed the onset of autoimmune diabetes in two different diabetogenic T cell transfer models. Mechanistically, macrophages pre-conditioned with the MIF inhibitor featured a refractory capacity to trigger T cell activation by keeping them in a naïve state. This study underlines a possible role for MIF/CD74 signaling pathways in promoting macrophage-mediated inflammation in T1D. As therapies directed at the MIF/CD74 pathway are in clinical development, new opportunities may be proposed for arresting T1D progression.

Animal models of human type 1 diabetes for evaluating combination therapies and successful translation to the patient with type 1 diabetes

Animal models of human type 1 diabetes will be of a great importance for the evaluation of new combination therapies with curative potential. However, reliable predictive power for successful translation to patients with type 1 diabetes is crucial. This will be particularly important in the future when evaluating success of new combination therapies that show great promise for preservation and restoration of beta cell mass and thereby reverse the type 1 diabetic hyperglycaemia. But not all spontaneous animal models are equally well suited for this purpose. The advantages and disadvantages of the three spontaneous rat models (BioBreeding diabetes-prone [BB] rat, Komeda [KDP] rat, and LEW.1AR1-iddm [IDDM] rat) as well as the NOD mouse, compared with the characteristics of human type 1 diabetes, are considered in this review.

Regulation of type 1 diabetes development and B-cell activation in nonobese diabetic mice by early life exposure to a diabetogenic environment

Microbes, including viruses, influence type 1 diabetes (T1D) development, but many such influences remain undefined. Previous work on underlying immune mechanisms has focussed on cytokines and T cells. Here, we compared two nonobese diabetic (NOD) mouse colonies, NODlow and NODhigh, differing markedly in their cumulative T1D incidence (22% vs. 90% by 30 weeks in females). NODhigh mice harbored more complex intestinal microbiota, including several pathobionts; both colonies harbored segmented filamentous bacteria (SFB), thought to suppress T1D. Young NODhigh females had increased B-cell activation in their mesenteric lymph nodes. These phenotypes were transmissible. Co-housing of NODlow with NODhigh mice after weaning did not change T1D development, but T1D incidence was increased in female offspring of co-housed NODlow mice, which were exposed to the NODhigh environment both before and after weaning. These offspring also acquired microbiota and B-cell activation approaching those of NODhigh mice. In NODlow females, the low rate of T1D was unaffected by cyclophosphamide but increased by PD-L1 blockade. Thus, environmental exposures that are innocuous later in life may promote T1D progression if acquired early during immune development, possibly by altering B-cell activation and/or PD-L1 function. Moreover, T1D suppression in NOD mice by SFB may depend on the presence of other microbial influences. The complexity of microbial immune regulation revealed in this murine model may also be relevant to the environmental regulation of human T1D.

Immunotherapy for type 1 diabetes

INTRODUCTION

Although many approaches have been tested to overcome the insulin dependence caused by the pancreatic β-cells destruction observed in individuals affected by type 1 diabetes (T1D), medical research has largely failed to halt the onset or to reverse T1D.

METHODS

In this work, the state of the art of immunotherapy will be examined, and the most important achievement in the field will be critically discussed. Particularly, we will focus on the clinical aspect, thus avoiding the tedious preclinical work done in NOD mice, which has been so poorly translated to the bedside.

CONCLUSIONS

Stem cell therapies achieved thus this far the most promising results, while immune ablation and standard immunosuppressants did not maintain the premises of preclinical results. The next step will be to generate a feasible and safe clinical approach in order to cure the thousands of patients affected by T1D.

Vitamin D, sub-inflammation and insulin resistance. A window on a potential role for the interaction between bone and glucose metabolism

Vitamin D is a key hormone involved in the regulation of calcium/phosphorous balance and recently it has been implicated in the pathogenesis of sub-inflammation, insulin resistance and obesity. The two main forms of vitamin D are cholecalciferol (Vitamin D3) and ergocalciferol (Vitamin D2): the active form (1,25-dihydroxyvitamin D) is the result of two hydroxylations that take place in liver, kidney, pancreas and immune cells. Vitamin D increases the production of some anti-inflammatory cytokines and reduces the release of some pro-inflammatory cytokines. Low levels of Vitamin D are also associated with an up-regulation of TLRs expression and a pro-inflammatory state. Regardless of the effect on inflammation, Vitamin D seems to directly increase insulin sensitivity and secretion, through different mechanisms. Considering the importance of low grade chronic inflammation in metabolic syndrome, obesity and diabetes, many authors hypothesized the involvement of this nutrient/hormone in the pathogenesis of these diseases. Vitamin D status could alter the balance between pro and anti-inflammatory cytokines and thus affect insulin action, lipid metabolism and adipose tissue function and structure. Numerous studies have shown that Vitamin D concentrations are inversely associated with pro-inflammatory markers, insulin resistance, glucose intolerance and obesity. Interestingly, some longitudinal trials suggested also an inverse association between vitamin D status and incident type 2 diabetes mellitus. However, vitamin D supplementation in humans showed controversial effects: with some studies demonstrating improvements in insulin sensitivity, glucose and lipid metabolism while others showing no beneficial effect on glycemic control and on inflammation. In conclusion, although the evidences of a significant role of Vitamin D on inflammation, insulin resistance and insulin secretion in the pathogenesis of obesity, metabolic syndrome and type 2 diabetes, its potential function in treatment and prevention of type 2 diabetes mellitus is unclear. Encouraging results have emerged from Vitamin D supplementation trials on patients at risk of developing diabetes and further studies are needed to fully explore and understand its clinical applications.

Targeting innate immunity to downmodulate adaptive immunity and reverse type 1 diabetes

Type 1 diabetes (T1D) is characterized by specific destruction of pancreatic insulin-producing beta cells accompanied by evidence of beta-cell-directed autoimmunity such as autoreactive T cells and islet autoantibodies (IAAs). Currently, T1D cannot be prevented or reversed in humans. T1D is easy to prevent in the nonobese diabetic (NOD) spontaneous mouse model but reversing new-onset T1D in mice is more difficult. Since the discovery of the T-cell receptor in the 1980s and the subsequent identification of autoreactive T cells directed toward beta-cell antigens (eg, insulin, glutamic acid decarboxylase), the dream of antigen-specific immunotherapy has dominated the field with its promise of specificity and limited side effects. While such approaches have worked in the NOD mouse, however, dozens of human trials have failed. Broader immunosuppressive approaches (originally cyclosporine, subsequently anti-CD3 antibody) have shown partial successes (e.g., prolonged C peptide preservation) but no major therapeutic efficacy or disease reversal. Human prevention trials have failed, despite the ease of such approaches in the NOD mouse. In the past 50 years, the incidence of T1D has increased dramatically, and one explanation is the “hygiene hypothesis”, which suggests that decreased exposure of the innate immune system to environmental immune stimulants (e.g., bacterial products such as Toll-like receptor (TLR) 4-stimulating lipopolysaccharide [LPS]) dramatically affects the adaptive immune system and increases subsequent autoimmunity. We have tested the role of innate immunity in autoimmune T1D by treating acute-onset T1D in NOD mice with anti-TLR4/MD-2 agonistic antibodies and have shown a high rate of disease reversal. The TLR4 antibodies do not directly stimulate T cells but induce tolerogenic antigen-presenting cells (APCs) that mediate decreased adaptive T-cell responses. Here, we review our current knowledge and suggest future prospects for targeting innate immunity in T1D immunotherapy.

Use of short interfering RNA delivered by cationic liposomes to enable efficient down-regulation of PTPN22 gene in human T lymphocytes

Type 1 diabetes and thyroid disease are T cell-dependent autoimmune endocrinopathies. The standard substitutive administration of the deficient hormones does not halt the autoimmune process; therefore, development of immunotherapies aiming to preserve the residual hormonal cells, is of crucial importance. PTPN22 C1858T mutation encoding for the R620W lymphoid tyrosine phosphatase variant, plays a potential pathophysiological role in autoimmunity. The PTPN22 encoded protein Lyp is a negative regulator of T cell antigen receptor signaling; R620W variant, leading to a gain of function with paradoxical reduced T cell activation, may represent a valid therapeutic target. We aimed to develop novel wild type PTPN22 short interfering RNA duplexes (siRNA) and optimize their delivery into Jurkat T cells and PBMC by using liposomal carriers. Conformational stability, size and polydispersion of siRNA in lipoplexes was measured by CD spectroscopy and DLS. Lipoplexes internalization and toxicity evaluation was assessed by confocal microscopy and flow cytometry analysis. Their effect on Lyp expression was evaluated by means of Western Blot and confocal microscopy. Functional assays through engagement of TCR signaling were established to evaluate biological consequences of down-modulation. Both Jurkat T cells and PBMC were efficiently transfected by stable custom lipoplexes. Jurkat T cell morphology and proliferation was not affected. Lipoplexes incorporation was visualized in CD3+ but also in CD3- peripheral blood immunotypes without signs of toxicity, damage or apoptosis. Efficacy in affecting Lyp protein expression was demonstrated in both transfected Jurkat T cells and PBMC. Moreover, impairment of Lyp inhibitory activity was revealed by increase of IL-2 secretion in culture supernatants of PBMC following anti-CD3/CD28 T cell receptor-driven stimulation. The results of our study open the pathway to future trials for the treatment of autoimmune diseases based on the selective inhibition of variant PTPN22 allele using lipoplexes of siRNA antisense oligomers.

miR-375 controls porcine pancreatic stem cell fate by targeting 3-phosphoinositide-dependent protein kinase-1 (Pdk1)

OBJECTIVES

miR-375 is one of the highly expressed microRNAs (miRNAs) found in pancreatic islets of both humans and mice. In this study, we investigated functions of miRNA miR-375 in porcine pancreatic stem cells (PSC).

MATERIALS AND METHODS

We transfected mimic and inhibitor of miR-375 in PSCs to measure functional roles of the microRNA and its effects on cell cycle proliferation and cell differentiation were determined. Luciferase assays were also performed to reveal the target gene of miR-375.

RESULTS

Overexpression of miR-375 suppressed proliferation, promoted apoptosis and inhibited differentiation into islet-like cells. PDK1 was identified as being a target of miR-375. Furthermore, we found that overexpression of miR-375 inhibited activation of the PDK1-AKT signalling pathway.

CONCLUSION

miR-375 directly targeted PDK1 in porcine PSCs, suppressing cell proliferation and differentiation into islet-like cells.

PI3Kγ Deficient NOD-Mice Are Protected from Diabetes by Restoring the Balance of Regulatory to Effector-T-Cells

With a steady increase in its incidence and lack of curative treatment, type 1 diabetes (T1D) has emerged as a major health problem worldwide. To design novel effective therapies, there is a pressing need to identify regulatory targets controlling the balance of autoreactive to regulatory-T-cells (Tregs). We previously showed that the inhibition of the γ-subunit of the Phosphoinositide-3-kinase (PI3K), significantly suppress autoimmune-diabetes. To further delineate the mechanisms and the selectivity of specific immune modulation by PI3Kγ-inhibition, we developed a new NOD mouse model of T1D lacking the γ-subunit of PI3K. Strikingly, the loss of PI3Kγ protected 92% of the NOD-mice from developing spontaneous diabetes. The NOD.PI3Kγ-/- mice are protected from insulitis secondary to a defect in CD4 and CD8 autoreactive-T-cells activation and survival. In addition, PI3Kγ-deficiency promoted Treg generation in-vitro and in-vivo. Furthermore, PI3Kγ-inhibitor (AS605240) inhibited proliferation and cytokine production of a human CD4+ T-cell clone specific for GAD555-567 peptide that was isolated from a patient with T1D. These studies demonstrate the key role of the PI3Kγ pathway in regulating autoimmune-diabetes and provide rationales for future devise of anti- PI3Kγ therapy in T1D.

The use of hematopoietic stem cells in autoimmune diseases

Hematopoietic stem cells (HSCs) have been shown recently to hold much promise in curing autoimmune diseases. Newly diagnosed Type 1 diabetes individuals have been successfully reverted to normoglycemia by administration of autologous HSCs in association with a nonmyeloablative regimen (antithymocyte globulin + cyclophasmide). Furthermore, recent trials reported positive results by using HSCs in treatment of systemic sclerosis, multiple sclerosis and rheumatoid arthritis as well. Early data suggested that HSCs possess immunological properties that may be harnessed to alleviate the symptoms of individuals with autoimmune disorders and possibly induce remission of autoimmune diseases. Mechanistically, HSCs may facilitate the generation of regulatory T cells, may inhibit the function of autoreactive T-cell function and may reshape the immune system.

Effect of 6-months' vitamin D supplementation on residual beta cell function in children with type 1 diabetes: a case control interventional study

BACKGROUND

The aim of this study was to evaluate the effect of short-term vitamin D supplementation on the decline of residual beta cell function (RBCF) in children with type 1 diabetes (T1D).

METHODS

The study involved an intervention group (cholecalciferol 2000 IU/day and calcium 25 mg/kg/day for 6 months) comprising 15 children aged 6-12 years and within 1-2 years of diagnosis of T1D. Fifteen age-matched T1D patients were followed up as controls. Stimulated C-peptide levels were estimated at baseline and 6 months.

RESULTS

The mean decrease in stimulated C-peptide levels in the intervention group was lower (-0.048±0.15 ng/mL) as compared with the controls (-0.107±0.23 ng/mL) but did not reach statistical significance (p=0.472). The percent decrease in stimulated C-peptide from baseline to endpoint (8.3% vs. 20.3%, p=0.357) and the monthly decrease (0.008 ng/mL vs. 0.017 ng/mL, p=0.22) were non-significantly lower in the intervention group compared with the control group. Three (20%) patients progressed to undetectable stimulated C-peptide (≤0.01 ng/mL) over the study period in the control group as compared with one (6%) in the intervention group (p-value 0.260).

CONCLUSIONS

There was a trend towards lesser decline of RBCF with short term cholecalciferol supplementation in children with T1D. Further larger studies are urgently needed to explore the beneficial effects of the relatively inexpensive vitamin D supplementation on RBCF.

Experimental Diabetes Mellitus in Different Animal Models

Animal models have historically played a critical role in the exploration and characterization of disease pathophysiology and target identification and in the evaluation of novel therapeutic agents and treatments in vivo. Diabetes mellitus disease, commonly known as diabetes, is a group of metabolic disorders characterized by high blood glucose levels for a prolonged time. To avoid late complications of diabetes and related costs, primary prevention and early treatment are therefore necessary. Due to its chronic symptoms, new treatment strategies need to be developed, because of the limited effectiveness of the current therapies. We overviewed the pathophysiological features of diabetes in relation to its complications in type 1 and type 2 mice along with rat models, including Zucker Diabetic Fatty (ZDF) rats, BB rats, LEW 1AR1/-iddm rats, Goto-Kakizaki rats, chemically induced diabetic models, and Nonobese Diabetic mouse, and Akita mice model. The advantages and disadvantages that these models comprise were also addressed in this review. This paper briefly reviews the wide pathophysiological and molecular mechanisms associated with type 1 and type 2 diabetes, particularly focusing on the challenges associated with the evaluation and predictive validation of these models as ideal animal models for preclinical assessments and discovering new drugs and therapeutic agents for translational application in humans.

Mobilization without immune depletion fails to restore immunological tolerance or preserve beta cell function in recent onset type 1 diabetes

Granulocyte colony-stimulating factor (G-CSF) has been used to restore immune competence following chemoablative cancer therapy and to promote immunological tolerance in certain settings of autoimmunity. Therefore, we tested the potential of G-CSF to impact type 1 diabetes (T1D) progression in patients with recent-onset disease [n = 14; n = 7 (placebo)] and assessed safety, efficacy and mechanistic effects on the immune system. We hypothesized that pegylated G-CSF (6 mg administered subcutaneously every 2 weeks for 12 weeks) would promote regulatory T cell (Treg) mobilization to a degree capable of restoring immunological tolerance, thus preventing further decline in C-peptide production. Although treatment was well tolerated, G-CSF monotherapy did not affect C-peptide production, glycated haemoglobin (HbA1c) or insulin dose. Mechanistically, G-CSF treatment increased circulating neutrophils during the 12-week course of therapy (P < 0·01) but did not alter Treg frequencies. No effects were observed for CD4(+) : CD8(+) T cell ratio or the ratio of naive : memory (CD45RA(+)/CD45RO(+)) CD4(+) T cells. As expected, manageable bone pain was common in subjects receiving G-CSF, but notably, no severe adverse events such as splenomegaly occurred. This study supports the continued exploration of G-CSF and other mobilizing agents in subjects with T1D, but only when combined with immunodepleting agents where synergistic mechanisms of action have previously demonstrated efficacy towards the preservation of C-peptide.

Explaining the increased mortality in type 1 diabetes

Despite large improvements in the management of glucose levels and in the treatment of cardiovascular risk factors, the mortality rate in individuals with type 1 diabetes (T1D) is still high. Recently, Lind et al found that T1D individuals with glycated hemoglobin levels of 6.9% or lower had a risk of death from any cause or from cardiovascular causes that is twice as high as the risk for matched controls. T1D is a chronic disease with an early onset (e.g., pediatric age) and thus in order to establish a clear correlation between death rate and the glycometabolic control, the whole history of glycemic control should be considered; particularly in the early years of diabetes. The switch from a normo- to hyperglycemic milieu in an individual with T1D in the pediatric age, represents a stressful event that may impact outcomes and death rate many years later. In this paper we will discuss the aforementioned issues, and offer our view on these findings, paying a particular attention to the several alterations occurring in the earliest phases of T1D and to the many factors that may be associated with the chronic history of T1D. This may help us to better understand the recently published death rate data and to develop future innovative and effective preventive strategies.

Human iPS cell-derived insulin producing cells form vascularized organoids under the kidney capsules of diabetic mice

Type 1 diabetes (T1D) is caused by autoimmune disease that leads to the destruction of pancreatic β-cells. Transplantation of cadaveric pancreatic organs or pancreatic islets can restore normal physiology. However, there is a chronic shortage of cadaveric organs, limiting the treatment of the majority of patients on the pancreas transplantation waiting list. Here, we hypothesized that human iPS cells can be directly differentiated into insulin producing cells (IPCs) capable of secreting insulin. Using a series of pancreatic growth factors, we successfully generated iPS cells derived IPCs. Furthermore, to investigate the capability of these cells to secrete insulin in vivo, the differentiated cells were transplanted under the kidney capsules of diabetic immunodeficient mice. Serum glucose levels gradually declined to either normal or near normal levels over 150 days, suggesting that the IPCs were secreting insulin. In addition, using MRI, a 3D organoid appeared as a white patch on the transplanted kidneys but not on the control kidneys. These organoids showed neo-vascularization and stained positive for insulin and glucagon. All together, these data show that a pancreatic organ can be created in vivo providing evidence that iPS cells might be a novel option for the treatment of T1D.