Prediction and prevention of type 1 diabetes: progress, problems, and prospects

Phytoconstituents of Nymphaea rubra flowers and their anti-diabetic metabolic targets

Nymphaea rubra (N. rubra) flowers are prevalent in subtropical regions for both dietary and traditional medicinal purposes, attributing to their beneficial properties in supporting overall health. This study first time provides descriptions of the antidiabetic and dyslipidemic properties employing STZ induced high fat diet fed diabetic rats and inhibition of α-amylase enzyme activity first by in vitro analyses, followed by a confirmatory in silico study to create a stronger biochemical rationale. Furthermore, in 3 T3-L1 cells, this extract promoted the suppression of adipogenesis. GC-MS investigation of the ethyl acetate fraction of ethanolic extract of N. rubra flowers revealed the presence of marker compounds of N. rubra, Nuciferine, and Apomorphine, which were the focus of molecular docking studies. The acquired concentrations of Nuciferine (22.39%) and 10, 11-dimethoxy-Apomorphine (1.47%) were detected. Together with other alkaloids identified by GC-MS analysis from this extract, mechanistically suggested that it might be caused by the synergistic impact of these bioactive chemicals. Molecular docking has been done to check the binding affinities of various isolated phytochemicals with HPAA, the dose-response effect of 100 mg/kg and 250 mg/kg of flower extract after 30 days showed a significant effect on body weight, food, water intake, serum insulin, FBG, OGTT, lipid profile, glycated haemoglobin, liver and kidney function test. Kidney histopathology results show a significant effect. These findings offer a strong foundation for the potential application of the ethyl acetate fraction of ethanolic extract from Nymphaea rubra flowers and its bioactive constituent in an in vivo system for the treatment and control of diabetes and its associated condition dyslipidemia.

Serum proteomics of mother-infant dyads carrying HLA-conferred type 1 diabetes risk

In-utero and dietary factors make important contributions toward health and development in early childhood. In this respect, serum proteomics of maturing infants can provide insights into studies of childhood diseases, which together with perinatal proteomes could reveal further biological perspectives. Accordingly, to determine differences between feeding groups and changes in infancy, serum proteomics analyses of mother-infant dyads with HLA-conferred susceptibility to type 1 diabetes (n = 22), weaned to either an extensively hydrolyzed or regular cow's milk formula, were made. The LC-MS/MS analyses included samples from the beginning of third trimester, the time of delivery, 3 months postpartum, cord blood, and samples from the infants at 3, 6, 9, and 12 months. Correlations between ranked protein intensities were detected within the dyads, together with perinatal and age-related changes. Comparison with intestinal permeability data revealed a number of significant correlations, which could merit further consideration in this context.

Teplizumab: type 1 diabetes mellitus preventable?

Type 1 diabetes mellitus (T1DM) is an autoimmune condition driven by T lymphocytes that specifically declines the function of beta cells of pancreas. Immunological treatments aim to stop this decline in β-cell function thus preventing TIDM. Although TIDM occur at any age, it is one of the most common chronic disorders in children. T1DM accounts for 5 to 10% of all cases of diabetes amounting 21-42 million affected persons. Teplizumab is a novel drug recently approved by the US FDA for the treatment of T1DM. This drug reduces abnormal glucose tolerance who are at high risk for developing T1DM and have antibodies suggesting an immunological attack on their pancreas. A 14-day infusion of the drug prevents T cells' attack of the insulin-producing cells of the pancreas. Adverse events due to teplizumab reported so far mild and of limited duration. This review gives an overview of the preclinical and clinical research on teplizumab for their role in new-onset T1DM.

Metabolic and Metabolomic Insights Regarding the Omega-3 PUFAs Intake in Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is currently considered an autoimmune disease characterized by the destruction of pancreatic β-cells, insulin deficiency, and dysglycemia. Dietary factors, including omega-3 polyunsaturated fatty acids (ω-3 PUFAs), were reported to influence T1DM. Therefore, a better understanding of the potential role of ω-3 PUFAs in the development and progression of T1DM will help to improve the clinical management of the disease. In this review, we explored the current understanding of molecular mechanisms and signaling pathways induced by ω-3 PUFAs and the beneficial effects of ω-3 PUFAs intake in the prevention and treatment of T1DM, as well as the underlying possible metabolomic (lipidomics) changes.

Wip1 regulates the immunomodulatory effects of murine mesenchymal stem cells in type 1 diabetes mellitus via targeting IFN-α/BST2

Mesenchymal stem cells (MSCs) show significant therapeutic effects in type 1 diabetes mellitus (T1DM) as regulating the inflammatory processes. However, little is known about the detailed process of MSCs immunosuppression in T1DM. In this study, we investigated the effects of wild-type p53-induce phosphatase 1 (Wip1) on regulating MSCs immunosuppressive capacities in T1DM mice. We found that Wip1 knockout (Wip1-/-) MSCs had lower therapeutic effects in T1DM mice, and displayed weaker immunosuppressive capability. In vivo distribution analysis results indicated thatWip1-/-MSCs could home to the damaged pancreas and increase the expression of tumor necrosis factor-α (TNF-α), interleukin-17a (IL-17a), interferon-α(IFN-α), IFN-β, and IFN-γ, while decrease the expression of IL-4 and IL-10. Moreover, we confirmedWip1-/-MSCs exhibited weaker immunosuppressive capacity, as evidenced by enhanced expression of bone marrow stromal cell antigen 2(BST2) and IFN-α. In conclusion, these results revealed Wip1 affects MSCs immunomodulation by regulating the expression of IFN-α/BST2. Our study uncovered that Wip1 is required to regulate the therapeutic effects of MSCs on T1DM treatment, indicating a novel role of Wip1 in MSCs immunoregulation properties.

Autoimmune thyroid disease and type 1 diabetes mellitus: same pathogenesis; new perspective?

Autoimmune thyroid disease (AITD) and type 1 diabetes mellitus (T1DM) are two common autoimmune diseases that can occur concomitantly. In general, patients with diabetes have a high risk of AITD. It has been proposed that a complex genetic basis together with multiple nongenetic factors make a variable contribution to the pathogenesis of T1DM and AITD. In this paper, we summarize current knowledge in the field regarding potential pathogenic factors of T1DM and AITD, including human leukocyte antigen, autoimmune regulator, lymphoid protein tyrosine phosphatase, forkhead box protein P3, cytotoxic T lymphocyte-associated antigen, infection, vitamin D deficiency, and chemokine (C-X-C motif) ligand. These findings offer an insight into future immunotherapy for autoimmune diseases.

Diverse therapeutic efficacies and more diverse mechanisms of nicotinamide

BACKGROUND

Nicotinamide (NAM) is a form of vitamin B3 that, when administered at near-gram doses, has been shown or suggested to be therapeutically effective against many diseases and conditions. The target conditions are incredibly diverse ranging from skin disorders such as bullous pemphigoid to schizophrenia and depression and even AIDS. Similar diversity is expected for the underlying mechanisms. In a large portion of the conditions, NAM conversion to nicotinamide adenine dinucleotide (NAD⁺) may be a major factor in its efficacy. The augmentation of cellular NAD⁺ level not only modulates mitochondrial production of ATP and superoxide, but also activates many enzymes. Activated sirtuin proteins, a family of NAD⁺-dependent deacetylases, play important roles in many of NAM's effects such as an increase in mitochondrial quality and cell viability countering neuronal damages and metabolic diseases. Meanwhile, certain observed effects are mediated by NAM itself. However, our understanding on the mechanisms of NAM's effects is limited to those involving certain key proteins and may even be inaccurate in some proposed cases.

AIM OF REVIEW

This review details the conditions that NAM has been shown to or is expected to effectively treat in humans and animals and evaluates the proposed underlying molecular mechanisms, with the intention of promoting wider, safe therapeutic application of NAM.

KEY SCIENTIFIC CONCEPTS OF REVIEW

NAM, by itself or through altering metabolic balance of NAD⁺ and tryptophan, modulates mitochondrial function and activities of many molecules and thereby positively affects cell viability and metabolic functions. And, NAM administration appears to be quite safe with limited possibility of side effects which are related to NAM's metabolites.

Release profile of insulin from pH-sensitive hydrogel and its hypoglycemic effect by oral administration

The purpose of this study was to investigate the release profile and in vivo hypoglycemic effect of insulin (INS)-loaded pH-sensitive hydrogel (INS-TPM950) administrated by oral route. TPM950 was fabricated via a free polymerization method and its inner morphology was observed with a scanning electron microscope (SEM). INS was encapsulated into TPM950 by an adsorption method, and the in vitro release profiles of INS from INS-TPM950 were revealed in pH 1.2 and 6.8. To investigate the hypoglycemic effect of INS-TPM950, Male Wistar rats were used in modeling of diabetes mellitus by multiple intraperitoneal injection of alloxan. The in vivo hypoglycemic effect of oral INS-TPM950 was studied, and the optimal dosage was also determined. SEM photograph showed that abundant 3D meshes were distributed in the inner of TPM950 hydrogel. INS release profile suggested that only 18.2 ± 11.3% INS was released in pH 1.2, but over 88.8 ± 4.9% was delivered into phosphate buffer solution in pH 6.8. After injection to the diabetic rats, the released INS solution from INS-TPM950 exhibited an obvious hypoglycemic effect. Oral administration of 50.0 I.U./kg of INS-TPM950 showed a slow but effective hypoglycemic effect, and the lowest blood glucose level was reached to 47.5 ± 5.5% of the original level. Therefore, this formulation had a potential application in diabetes treatment via oral ingestion.

Molecular signatures differentiate immune states in type 1 diabetic families

Mechanisms associated with type 1 diabetes (T1D) development remain incompletely defined. Using a sensitive array-based bioassay where patient plasma is used to induce transcriptional responses in healthy leukocytes, we previously reported disease-specific, partially interleukin (IL)-1-dependent signatures associated with preonset and recent onset (RO) T1D relative to unrelated healthy control subjects (uHC). To better understand inherited susceptibility in T1D families, we conducted cross-sectional and longitudinal analyses of healthy autoantibody-negative (AA(-)) high HLA-risk siblings (HRS) (DR3 and/or DR4) and AA(-) low HLA-risk siblings (LRS) (non-DR3/non-DR4). Signatures, scored with a novel ontology-based algorithm, and confirmatory studies differentiated the RO T1D, uHC, HRS, and LRS plasma milieus. Relative to uHC, T1D family members exhibited an elevated inflammatory state, consistent with innate receptor ligation that was independent of HLA, AA, or disease status and included elevated plasma IL-1α, IL-12p40, CCL2, CCL3, and CCL4 levels. Longitudinally, signatures of T1D progressors exhibited increasing inflammatory bias. Conversely, HRS possessing decreasing AA titers revealed emergence of an IL-10/transforming growth factor-β-mediated regulatory state that paralleled temporal increases in peripheral activated CD4(+)/CD45RA(-)/FoxP3(high) regulatory T-cell frequencies. In AA(-) HRS, the familial innate inflammatory state also was temporally supplanted by immunoregulatory processes, suggesting a mechanism underlying the decline in T1D susceptibility with age.

Risk of type 1 diabetes progression in islet autoantibody-positive children can be further stratified using expression patterns of multiple genes implicated in peripheral blood lymphocyte activation and function

There is tremendous scientific and clinical value to further improving the predictive power of autoantibodies because autoantibody-positive (AbP) children have heterogeneous rates of progression to clinical diabetes. This study explored the potential of gene expression profiles as biomarkers for risk stratification among 104 AbP subjects from the Diabetes Autoimmunity Study in the Young (DAISY) using a discovery data set based on microarray and a validation data set based on real-time RT-PCR. The microarray data identified 454 candidate genes with expression levels associated with various type 1 diabetes (T1D) progression rates. RT-PCR analyses of the top-27 candidate genes confirmed 5 genes (BACH2, IGLL3, EIF3A, CDC20, and TXNDC5) associated with differential progression and implicated in lymphocyte activation and function. Multivariate analyses of these five genes in the discovery and validation data sets identified and confirmed four multigene models (BI, ICE, BICE, and BITE, with each letter representing a gene) that consistently stratify high- and low-risk subsets of AbP subjects with hazard ratios >6 (P < 0.01). The results suggest that these genes may be involved in T1D pathogenesis and potentially serve as excellent gene expression biomarkers to predict the risk of progression to clinical diabetes for AbP subjects.

Restoration of the unfolded protein response in pancreatic β cells protects mice against type 1 diabetes

Perturbations in endoplasmic reticulum (ER) homeostasis can evoke stress responses leading to aberrant glucose and lipid metabolism. ER dysfunction is linked to inflammatory disorders, but its role in the pathogenesis of autoimmune type 1 diabetes (T1D) remains unknown. We identified defects in the expression of unfolded protein response (UPR) mediators ATF6 (activating transcription factor 6) and XBP1 (X-box binding protein 1) in β cells from two different T1D mouse models and then demonstrated similar defects in pancreatic β cells from T1D patients. Administration of a chemical ER stress mitigator, tauroursodeoxycholic acid (TUDCA), at the prediabetic stage resulted in a marked reduction of diabetes incidence in the T1D mouse models. This reduction was accompanied by (i) a significant decrease in aggressive lymphocytic infiltration in the pancreas, (ii) improved survival and morphology of β cells, (iii) reduced β cell apoptosis, (iv) preserved insulin secretion, and (v) restored expression of UPR mediators. TUDCA's actions were dependent on ATF6 and were lost in mice with β cell-specific deletion of ATF6. These data indicate that proper maintenance of the UPR is essential for the preservation of β cells and that defects in this process can be chemically restored for preventive or therapeutic interventions in T1D.

The pathogenesis and natural history of type 1 diabetes

The purpose of this article is to provide an overview that summarizes much in the way of our current state of knowledge regarding the pathogenesis and natural history of type 1 diabetes in humans. This information is presented to the reader as a series of seminal historical discoveries that, when advanced through research, transformed our understanding of the roles for the immune system, genes, and environment in the formation of this disease. In addition, where longitudinal investigations of these three facets occurred, their roles within the development of type 1 diabetes, from birth to symptomatic onset and beyond, are discussed, including their most controversial elements. Having an understanding of this disorder's pathogenesis and natural history is key for attempts seeking to understand the issues of what causes type 1 diabetes, as well as to develop a means to prevent and cure the disorder.

Transcriptional signatures as a disease-specific and predictive inflammatory biomarker for type 1 diabetes

The complex milieu of inflammatory mediators associated with many diseases is often too dilute to directly measure in the periphery, necessitating development of more sensitive measurements suitable for mechanistic studies, earlier diagnosis, guiding therapeutic decisions and monitoring interventions. We previously demonstrated that plasma samples from recent-onset type 1 diabetes (RO T1D) patients induce a proinflammatory transcriptional signature in freshly drawn peripheral blood mononuclear cells (PBMCs) relative to that of unrelated healthy controls (HC). Here, using cryopreserved PBMC, we analyzed larger RO T1D and HC cohorts, examined T1D progression in pre-onset samples, and compared the RO T1D signature to those associated with three disorders characterized by airway infection and inflammation. The RO T1D signature, consisting of interleukin-1 cytokine family members, chemokines involved in immunocyte chemotaxis, immune receptors and signaling molecules, was detected during early pre-diabetes and found to resolve post-onset. The signatures associated with cystic fibrosis patients chronically infected with Pseudomonas aeruginosa, patients with confirmed bacterial pneumonia, and subjects with H1N1 influenza all reflected immunological activation, yet each were distinct from one another and negatively correlated with that of T1D. This study highlights the remarkable capacity of cells to serve as biosensors capable of sensitively and comprehensively differentiating immunological states.

Altered B cell homeostasis is associated with type I diabetes and carriers of the PTPN22 allelic variant

The PTPN22 genetic variant 1858T, encoding Lyp620W, is associated with multiple autoimmune disorders for which the production of autoantibodies is a common feature, suggesting a loss of B cell tolerance. Lyp620W results in blunted BCR signaling in memory B cells. Because BCR signal strength is tightly coupled to central and peripheral tolerance, we examined whether Lyp620W impacts peripheral B cell homeostasis in healthy individuals heterozygous for the PTPN221858T variant. We found that these subjects display alterations in the composition of the B cell pool that include specific expansion of the transitional and anergic IgD(+)IgM(-)CD27(-) B cell subsets. The PTPN22 1858T variant was further associated with significantly diminished BCR signaling and a resistance to apoptosis in both transitional and naive B cells. Strikingly, parallel changes in both BCR signaling and composition of B cell compartment were observed in type 1 diabetic subjects, irrespective of PTPN22 genotype, revealing a novel immune phenotype and likely shared mechanisms leading to a loss of B cell tolerance. Our combined findings suggest that Lyp620W-mediated effects, due in part to the altered BCR signaling threshold, contribute to breakdown of peripheral tolerance and the entry of autoreactive B cells into the naive B cell compartment.

Loss of intra-islet CD20 expression may complicate efficacy of B-cell-directed type 1 diabetes therapies

OBJECTIVE

Consistent with studies in NOD mice, early clinical trials addressing whether depletion of B cells by the Rituximab CD20-specific antibody provides an effective means for type 1 diabetes reversal have produced promising results. However, to improve therapeutic efficacy, additional B-cell-depleting agents, as well as attempts seeking diabetes prevention, are being considered.

RESEARCH DESIGN AND METHODS

Autoantibodies, including those against insulin (IAAs), are used to identify at-risk subjects for inclusion in diabetes prevention trials. Therefore, we tested the ability of anti-CD20 to prevent diabetes in NOD mice when administered either before or after IAA onset.

RESULTS

The murine CD20-specific 18B12 antibody that like Rituximab, depletes the follicular (FO) but not marginal zone subset of B cells, efficiently inhibited diabetes development in NOD mice in a likely regulatory T-cell-dependent manner only when treatment was initiated before IAA detection. One implication of these results is that the FO subset of B cells preferentially contributes to early diabetes initiation events. However, most important, the inefficient ability of anti-CD20 treatment to exert late-stage diabetes prevention was found to be attributable to downregulation of CD20 expression upon B cell entry into pancreatic islets.

CONCLUSIONS

These findings provide important guidance for designing strategies targeting B cells as a potential means of diabetes intervention.

Immunology of Diabetes Society T-Cell Workshop: HLA class II tetramer-directed epitope validation initiative

BACKGROUND

Islet-antigen-specific CD4+ T cells are known to promote auto-immune destruction in T1D. Measuring T-cell number and function provides an important biomarker. In response to this need, we evaluated responses to proinsulin and GAD epitopes in a multicentre study.

METHODS

A tetramer-based assay was used in five participating centres to measure T-cell reactivities to DR0401-restricted epitopes. Three participating centres concurrently performed ELISPOT or immunoblot assays. Each centre used blind-coded, centrally distributed peptide and tetramer reagents.

RESULTS

All participating centres detected responses to auto-antigens and the positive control antigen, and in some cases cloned the corresponding T cells. However, response rates varied among centres. In total, 74% of patients were positive for at least one islet epitope. The most commonly recognized epitope was GAD270-285. Only a minority of the patients tested by tetramer and ELISPOT were concordant for both assays.

CONCLUSIONS

This study successfully detected GAD and proinsulin responses using centrally distributed blind-coded reagents. Centres with little previous experience using class II tetramer reagents implemented the assay. The variability in response rates observed for different centres suggests technical difficulties and/or heterogeneity within the local patient populations tested. Dual analysis by tetramer and ELISPOT or immunoblot assays was frequently discordant, suggesting that these assays detect distinct cell populations. Future efforts should investigate shared blood samples to evaluate assay reproducibility and longitudinal samples to identify changes in T-cell phenotype that correlate with changes in disease course.

Gain of function of cardiac ryanodine receptor in a rat model of type 1 diabetes

AIMS

Ventricular myocytes isolated from hearts of streptozotocin (STZ)-diabetic rats exhibit increased spontaneous Ca(2+) release. Studies attribute this defect to an enhancement in activity of type 2 ryanodine receptor (RyR2). To date, underlying reasons for RyR2 dysregulation remain undefined. This study assesses whether the responsiveness of RyR2 following stimulation by intrinsic ligands is being altered during experimental type 1 diabetes (T1D).

METHODS AND RESULTS

M-mode echocardiography established a cardiomyopathy in 8 weeks STZ-diabetic rats. Confocal microscopy confirmed an increase in the spontaneous Ca(2+) release in isolated ventricular myocytes. Western blots revealed no significant change in steady-state levels of the RyR2 protein. When purified to homogeneity and incorporated into planar lipid bilayers, RyR2 from STZ-diabetic rats (dRyR2) exhibited reduced current amplitude at ±35 mV. dRyR2 was also more responsive to intrinsic cytoplasmic activators Ca(2+), adenosine triphosphate, and cyclic adenosine diphosphate ribose and less responsive to the cytoplasmic deactivator Mg(2+). Threshold for the activation of RyR2 by trans (luminal) Ca(2+) was also reduced. These changes were independent of phosphorylation at Ser2808 and Ser2814. Two weeks of insulin treatment starting after 6 weeks of diabetes blunted the phenotype change, indicating that the gain of function is specific to the diabetes and not the result of STZ interacting directly with RyR2.

CONCLUSION

These data show, for the first time, that RyR2 is acquiring a gain-of-function phenotype independent of its phosphorylation status during T1D and provides new insights for the enhanced spontaneous Ca(2+) release in myocytes from T1D rats.

Use of transcriptional signatures induced in lymphoid and myeloid cell lines as an inflammatory biomarker in Type 1 diabetes

Inflammation is common to many disorders and responsible for tissue and organ damage. In many disorders, the associated peripheral cytokine milieu is dilute and difficult to measure, necessitating development of more sensitive and informative biomarkers for mechanistic studies, earlier diagnosis, and monitoring therapeutic interventions. Previously, we have shown that plasma of recent-onset (RO) Type 1 diabetes patients induces a disease-specific proinflammatory transcriptional profile in fresh peripheral blood mononuclear cells (PBMC) compared with that of healthy controls (HC). To eliminate assay variance introduced through the use of multiple donors or multiple draws of the same person over time, we evaluated human leukemia cell lines as potential surrogates for fresh PBMC. We 1) tested seven different cell lines in their power to differentiate RO from HC plasma and 2) compared the similarity of the signatures generated across the seven cell lines to that obtained with fresh PBMC. While each cell line tested exhibited a distinct transcriptional response when cultured with RO or HC plasma, the expression profile induced in any single cell line shared little identity with that of the other cell lines or fresh PBMC. In terms of regulated biological pathways, the transcriptional response of each cell line shared varying degrees of functional identity with fresh PBMC. These results indicate that use of human leukemia cell lines as surrogates for fresh PBMC has potential in detecting perturbations to the peripheral cytokine milieu. However, the response of each is distinct, possessing varying degrees of functional relatedness to that observed with PBMC.

Prognostic performance of metabolic indexes in predicting onset of type 1 diabetes

OBJECTIVE

In this investigation we evaluated nine metabolic indexes from intravenous glucose tolerance tests (IVGTTs) and oral glucose tolerance tests (OGTTs) in an effort to determine their prognostic performance in predicting the development of type 1 diabetes in those with moderate risk, as defined by familial relation to a type 1 diabetic individual, a positive test for islet cell antibodies and insulin autoantibody, but normal glucose tolerance.

RESEARCH DESIGN AND METHODS

Subjects (n = 186) who had a projected risk of 25-50% for developing type 1 diabetes within 5 years were followed until clinical diabetes onset or the end of the study as part of the Diabetes Prevention Trial-Type 1. Prognostic performance of the metabolic indexes was determined using receiver operating characteristic (ROC) curve and survival analyses.

RESULTS

Two-hour glucose from an OGTT most accurately predicted progression to disease compared with all other metabolic indicators with an area under the ROC curve of 0.67 (95% CI 0.59-0.76), closely followed by the ratio of first-phase insulin response (FPIR) to homeostasis model assessment of insulin resistance (HOMA-IR) with an area under the curve value of 0.66. The optimal cutoff value for 2-h glucose (114 mg/dl) maintained sensitivity and specificity values >0.60. The hazard ratio for those with 2-h glucose ≥ 114 mg/dl compared with those with 2-h glucose <114 mg/dl was 2.96 (1.67-5.22).

CONCLUSIONS

The ratio of FPIR to HOMA-IR from an IVGTT provided accuracy in predicting the development of type 1 diabetes similar to that of 2-h glucose from an OGTT, which, because of its lower cost, is preferred. The optimal cutoff value determined for 2-h glucose provides additional guidance for clinicians to identify subjects for potential prevention treatments before the onset of impaired glucose tolerance.

Teplizumab therapy for type 1 diabetes

IMPORTANCE OF THE FIELD

Type 1 diabetes mellitus (T1D) is a T-cell mediated autoimmune disease with selective destruction of beta cells. Immunological interventions are directed at arresting the loss of beta-cell function with the promise that this will make it easier for patients to control their glucose levels.

AREAS COVERED IN THIS REVIEW

This review provides a summary of the preclinical and clinical research published between 1992 and 2009 using teplizumab and other anti-CD3 antibodies to arrest the loss of beta-cell function in new onset T1D. Data from animal and human studies on the probable mechanism of action of teplizumab are also reviewed.

WHAT THE READER WILL GAIN

A broad perspective on the use of teplizumab in inducing disease specific tolerance.

TAKE HOME MESSAGE

In Phase I/II randomized control trials, in patients with new onset T1D, teplizumab slowed the rate of loss of beta-cell function over 2 years of follow-up. Treated patients had better glycemic control and lower insulin requirements. Adverse events so far are mild and of limited duration. Phase III clinical trials are underway to confirm these results and to determine if two courses of drug have greater efficacy in arresting loss of beta-cell function.

Trends of earlier and later responses of C-peptide to oral glucose challenges with progression to type 1 diabetes in diabetes prevention trial-type 1 participants

OBJECTIVE We studied the C-peptide response to oral glucose with progression to type 1 diabetes in Diabetes Prevention Trial-Type 1 (DPT-1) participants. RESEARCH DESIGN AND METHODS Among 504 DPT-1 participants <15 years of age, longitudinal analyses were performed in 36 progressors and 80 nonprogressors. Progressors had oral glucose tolerance tests (OGTTs) at baseline and every 6 months from 2.0 to 0.5 years before diagnosis; nonprogressors had OGTTs over similar intervals before their last visit. Sixty-six progressors and 192 nonprogressors were also studied proximal to and at diagnosis. RESULTS The 30-0 min C-peptide difference from OGTTs performed 2.0 years before diagnosis in progressors was lower than the 30-0 min C-peptide difference from OGTTs performed 2.0 years before the last visit in nonprogressors (P < 0.01) and remained lower over time. The 90-60 min C-peptide difference was positive at every OGTT before diagnosis in progressors, whereas it was negative at every OGTT before the last visit in nonprogressors (P < 0.01 at 2.0 years). The percentage whose peak C-peptide occurred at 120 min was higher in progressors at 2.0 years (P < 0.05); this persisted over time (P < 0.001 at 0.5 years). However, the peak C-peptide levels were only significantly lower at 0.5 years in progressors (P < 0.01). The timing of the peak C-peptide predicted type 1 diabetes (P < 0.001); peak C-peptide levels were less predictive (P < 0.05). CONCLUSIONS A decreased early C-peptide response to oral glucose and an increased later response occur at least 2 years before the diagnosis of type 1 diabetes.

Approaches in type 1 diabetes research: A status report

Type 1 diabetes is a multifactorial disease with an early age of onset, in which the insulin producing beta cell of the pancreas are destroyed because of autoimmunity. It is the second most common chronic disease in children and account for 5% to 10% of all diagnosed cases of diabetes. India is having an incidence of 10.6 cases/year/100,000, and recent studies indicate that the prevalence of type 1 diabetes in India is increasing. However in view of poor health care network, there is no monitoring system in the country. Of the 18 genomic intervals implicated for the risk to develop type 1 diabetes, the major histocompatibility complex (MHC) region on chromosome 6p21.31 has been the major contributor estimated to account for 40-50%, followed by 10% frequency of INS-VNTR at 5' flanking region of the insulin gene on chromosome 11p15.5. However, population studies suggest that > 95% of type 1 diabetes have HLA-DR3 or DR4, or both, and in family studies, sibling pairs affected with type 1 diabetes have a non-random distribution of shared HLA haplotypes. As predisposing genetic factors such as HLA alleles are known, immunological interventions to prevent type 1 diabetes are of great interest. In the present study we have reviewed the status of molecular genetics of the disease and the approaches that need to be adopted in terms of developing patient and suitable control cohorts in the country.

Pancreatic duodenal homeobox 1 protein is a novel beta-cell-specific autoantigen for type I diabetes

Pancreatic duodenal homeobox 1 (Pdx1) protein is a key transcription factor involved in the regulation of insulin gene expression that is expressed at high levels in the beta-cells of the pancreatic islets. We asked whether Pdx1 is a target of anti-islet autoimmunity in type I diabetes (T1D). Pdx1 autoantibodies (PAAs) were detected in non-obese diabetic (NOD) mice using ELISA, western blotting, and radioimmunoprecipitation of [(35)S]-labeled insulinoma cell line-derived Pdx1 protein. PAAs were detected as early as at 5 weeks of age, and generally peaked before the onset of clinically overt diabetes in diabetes-prone female NOD mice. Levels declined substantially after the onset of diabetes. PAAs were not detected in the sera of NOD-scid, C57BL/6, or BALB/c mice. The titers of PAAs in NOD mouse sera were as high as 1/93 750 by ELISA. The fine specificity of PAAs was determined by western blotting using a series of truncated recombinant Pdx1 proteins. The immunodominant epitopes were located to the C-terminus of the Pdx1 (p200-283) in NOD mice. PAAs also were detected in sera from human T1D patients, but the major epitopes were localized to amino acids 159-200 as well as the same region (p200-283) recognized by PAAs from NOD mice. Using [(3)H]thymidine incorporation, the p83 fragment of Pdx1 specifically stimulated proliferation of splenic T cells from recent-onset diabetic NOD mice. The presence of PAAs in prediabetic NOD mice and human T1D patients, and Pdx1-specific T-cell proliferation in NOD mice provide a strong rationale for further investigation of the pathogenic role of immune responses against Pdx1 in T1D.

Pro-inflammatory biomarkers during experimental gingivitis in patients with type 1 diabetes mellitus: a proof-of-concept study

AIM

To compare gingival crevicular fluid (GCF) biomarker levels and microbial distribution in plaque biofilm (SP) samples for subjects with type 1 diabetes (T1DM) versus healthy subjects without diabetes during experimental gingivitis (EG).

MATERIALS AND METHODS

A total of nine T1DM patients and nine healthy controls of age and gender similar to the T1DM patients were monitored for 35 days during EG. Hygiene practices were stopped for 3 weeks, and GCF, SP, plaque index (PI) and gingival index were determined. IL-1beta, IL-8, MMP-8 and MMP-9 were quantified by enzyme-linked immunosorbent assay, and SP samples were assessed by DNA-DNA hybridization for a panel of 40 subgingival microbial species.

RESULTS

IL-1beta levels in T1DM patients were elevated compared with healthy individuals, and showed differences between groups at 7-21 days while healthy patients showed IL-1beta increases from baseline to 14-21 days (p<0.05). Differences were observed in MMP-9 levels between patients with and without T1DM at 7-14 days (p<0.05). Orange complex species and PI measurements displayed a superior correlation with biomarker levels when compared with other complexes or clinical measurements during EG.

CONCLUSIONS

The mean GCF biomarker levels for IL-1beta and MMP-8 were most significantly elevated in T1DM subjects compared with healthy individuals during EG, not resulting from differences in the mean PI or microbial composition.

Pathway analysis of GWAS provides new insights into genetic susceptibility to 3 inflammatory diseases

Although the introduction of genome-wide association studies (GWAS) have greatly increased the number of genes associated with common diseases, only a small proportion of the predicted genetic contribution has so far been elucidated. Studying the cumulative variation of polymorphisms in multiple genes acting in functional pathways may provide a complementary approach to the more common single SNP association approach in understanding genetic determinants of common disease. We developed a novel pathway-based method to assess the combined contribution of multiple genetic variants acting within canonical biological pathways and applied it to data from 14,000 UK individuals with 7 common diseases. We tested inflammatory pathways for association with Crohn's disease (CD), rheumatoid arthritis (RA) and type 1 diabetes (T1D) with 4 non-inflammatory diseases as controls. Using a variable selection algorithm, we identified variants responsible for the pathway association and evaluated their use for disease prediction using a 10 fold cross-validation framework in order to calculate out-of-sample area under the Receiver Operating Curve (AUC). The generalisability of these predictive models was tested on an independent birth cohort from Northern Finland. Multiple canonical inflammatory pathways showed highly significant associations (p 10(-3)-10(-20)) with CD, T1D and RA. Variable selection identified on average a set of 205 SNPs (149 genes) for T1D, 350 SNPs (189 genes) for RA and 493 SNPs (277 genes) for CD. The pattern of polymorphisms at these SNPS were found to be highly predictive of T1D (91% AUC) and RA (85% AUC), and weakly predictive of CD (60% AUC). The predictive ability of the T1D model (without any parameter refitting) had good predictive ability (79% AUC) in the Finnish cohort. Our analysis suggests that genetic contribution to common inflammatory diseases operates through multiple genes interacting in functional pathways.

Reduced diabetes in btk-deficient nonobese diabetic mice and restoration of diabetes with provision of an anti-insulin IgH chain transgene

Type 1 diabetes results from T cell-mediated destruction of insulin-producing beta cells. Although elimination of B lymphocytes has proven successful at preventing disease, modulation of B cell function as a means to prevent type 1 diabetes has not been investigated. The development, fate, and function of B lymphocytes depend upon BCR signaling, which is mediated in part by Bruton's tyrosine kinase (BTK). When introduced into NOD mice, btk deficiency only modestly reduces B cell numbers, but dramatically protects against diabetes. In NOD, btk deficiency mirrors changes in B cell subsets seen in other strains, but also improves B cell-related tolerance, as indicated by failure to generate insulin autoantibodies. Introduction of an anti-insulin BCR H chain transgene restores diabetes in btk-deficient NOD mice, indicating that btk-deficient B cells are functionally capable of promoting autoimmune diabetes if they have a critical autoimmune specificity. This suggests that the disease-protective effect of btk deficiency may reflect a lack of autoreactive specificities in the B cell repertoire. Thus, signaling via BTK can be modulated to improve B cell tolerance, and prevent T cell-mediated autoimmune diabetes.

Incident dysglycemia and progression to type 1 diabetes among participants in the Diabetes Prevention Trial-Type 1

OBJECTIVE

We studied the incidence of dysglycemia and its prediction of the development of type 1 diabetes in islet cell autoantibody (ICA)-positive individuals. In addition, we assessed whether dysglycemia was sustained.

RESEARCH DESIGN AND METHODS

Participants (n = 515) in the Diabetes Prevention Trial-Type 1 (DPT-1) with normal glucose tolerance who underwent periodic oral glucose tolerance tests (OGTTs) were followed for incident dysglycemia (impaired fasting glucose, impaired glucose tolerance, and/or high glucose levels at intermediate time points of OGTTs). Incident dysglycemia at the 6-month visit was assessed for type 1 diabetes prediction.

RESULTS

Of 515 participants with a normal baseline OGTT, 310 (60%) had at least one episode of dysglycemia over a maximum follow-up of 7 years. Dysglycemia at the 6-month visit was highly predictive of the development of type 1 diabetes, both in those aged <13 years (P < 0.001) and those aged > or =13 years (P < 0.01). Those aged <13 years with dysglycemia at the 6-month visit had a high cumulative incidence (94% estimate by 5 years). Among those who developed type 1 diabetes after a dysglycemic OGTT and who had at least two OGTTs after the dysglycemic OGTT, 33 of 64 (52%) reverted back to a normal OGTT. However, 26 (79%) of the 33 then had another dysglycemic OGTT before diagnosis.

CONCLUSIONS

ICA-positive individuals with normal glucose tolerance had a high incidence of dysglycemia. Incident dysglycemia in those who are ICA positive is strongly predictive of type 1 diabetes. Children with incident dysglycemia have an especially high risk. Fluctuations in and out of the dysglycemic state are not uncommon before the onset of type 1 diabetes.

Advances in Type 1 diabetes therapeutics: immunomodulation and beta-cell salvage

Refinements in our understanding of the pathogenic mechanisms of Type 1 diabetes from studies of animal models and clinical observation have led to new clinical trials to prevent disease progression and restore the loss of beta-cells that defines the disease. Antigen-specific agents have shown initial promise and non-antigen-specific agents now have improved safety compared with older agents. In addition, preclinical studies with other agents have shown efficacy. Ultimately, a combination of immunologic and cellular therapies may be needed to restore metabolic control. Agents that augment recovery of dysfunctional beta-cells, and other compounds that may be able to induce beta-cell replication, are logical additions once immune tolerance is achieved.

B cell-targeted therapies in autoimmunity: rationale and progress

B cells are recognized as main actors in the autoimmune process. Autoreactive B cells can arise in the bone marrow or in the periphery and, if not properly inhibited or eliminated, can lead to autoimmune diseases through several mechanisms: autoantibody production and immune complex formation, cytokine and chemokine synthesis, antigen presentation, T cell activation, and ectopic lymphogenesis. The availability of agents capable of depleting B cells (that is, anti-CD20 and anti-CD22 monoclonal antibodies) or targeting B cell survival factors (atacicept and belimumab) opens new perspectives in the treatment of diseases such as systemic lupus erythematosus, rheumatoid arthritis, type 1 diabetes, and multiple sclerosis.

The TrialNet Natural History Study of the Development of Type 1 Diabetes: objectives, design, and initial results

OBJECTIVES

TrialNet's goal to test preventions for type 1 diabetes has created an opportunity to gain new insights into the natural history of pre-type 1 diabetes. The TrialNet Natural History Study (NHS) will assess the predictive value of existing and novel risk markers for type 1 diabetes and will find subjects for prevention trials.

RESEARCH DESIGN AND METHODS

The NHS is a three-phase, prospective cohort study. In phase 1 (screening), pancreatic autoantibodies (glutamic acid decarboxylase, insulin, ICA-512, and islet cell antibodies) are measured. Phase 2 (baseline risk assessment) includes oral glucose tolerance tests (OGTTs) in antibody-positive subjects and estimation of 5-yr diabetes risks according to the OGTT and number of confirmed positive antibody tests. Phase 3 (follow-up risk assessments) requires OGTTs every 6 months. In phases 2 and 3, samples are collected for future tests of T-lymphocyte function, autoantibody isotypes, RNA gene expression, and proteomics. The primary outcome is diabetes onset.

RESULTS

Of 12 636 relatives screened between March 2004 and December 2006, 605 (4.8%) were positive for at least one biochemical antibody. Of these, 322 were confirmed antibody positive and completed phase 2, of whom 296 subjects were given preliminary 5-yr diabetes risks of <25% (n = 132), > or =25% (n = 36), and > or =50% (n = 128) where the latter two categories represent different subjects based on number of confirmed positive antibodies (2, > or =25%; 3 or more, > or =50%) and/or an abnormal OGTT (> or =50%).

CONCLUSIONS

The NHS is identifying potential prevention trial subjects and is assembling a large cohort that will provide new natural history information about pre-type 1 diabetes. Follow-up to diabetes will help establish the biological significance and clinical value of novel type 1 diabetes risk markers.

Type 1 diabetes mellitus: primary, secondary, and tertiary prevention

We have entered the era of clinical trials to prevent type 1 diabetes mellitus (T1DM). Before 1922, when insulin was first given to a patient with diabetes, a diagnosis of T1DM was considered a death sentence. Advances in treatment for subjects with diabetes are not yet sufficient to prevent the deleterious impact of diabetes on both day-to-day activities and the early morbidity and mortality still associated with the disease. We now understand a great deal about blood glucose regulation and potential health complications associated with long-term T1DM, but the mystery of why, or the pathogenesis of this devastating disease, remains elusive. Great strides toward unraveling this mystery have been made over the past several decades. Even without definitive answers, we are moving from the period of discovery and animal research to the era of clinical trials. In this review, we wish to convey the palpable excitement in the field. It is time to determine if we can safely change the course of T1DM.

Closing the circle between the bedside and the bench: Toll-like receptors in models of virally induced diabetes

Animal models provide many strategies to unravel the complex interplay of genetic, immunologic, and environmental factors involved in the pathogenesis of type 1A (autoimmune) diabetes. Diabetes can be studied at multiple levels, and new technological advancements provide insights into the functioning of organelle and cellular structures. The role of innate immunity in the response to environmental pathogens has provided possible biochemical and molecular mechanisms which can explain certain clinical events in diabetes. These investigations may uncover new therapies and strategies to prevent type 1A diabetes.

New potential treatments for protection of pancreatic B-cell function in Type 1 diabetes

Type 1 diabetes mellitus results from the progressive and specific autoimmune destruction of insulin-secreting pancreatic B-cells, which develops over a period of years and continues after the initial clinical presentation. The ultimate goal of therapeutic intervention is prevention or reversal of the disease by the arrest of autoimmunity and by preservation/restoration of B-cell mass and function. Recent clinical trials of antigen-specific or non-specific immune therapies have proved that modulation of islet specific autoimmunity in humans and prevention of insulin secretion loss in the short term after the onset of disease is achievable. The identification of suitable candidates for therapy, appropriate dosage and timing, specificity of intervention and the side-effect profile are crucial for the success of any approach. Considering the complexity of the disease, it is likely that a rationally designed approach of combined immune-based therapies that target suppression of B-cell specific autoreactivity and maintenance of immune tolerance, coupled with islet regeneration or replacement of the destroyed B-cell mass, will prove to be most effective in causing remission/reversal of disease in a durable fashion.

Targeting CD22 reprograms B-cells and reverses autoimmune diabetes

OBJECTIVES

To investigate a B-cell-depleting strategy to reverse diabetes in naïve NOD mice.

RESEARCH DESIGN AND METHODS

We targeted the CD22 receptor on B-cells of naïve NOD mice to deplete and reprogram B-cells to effectively reverse autoimmune diabetes.

RESULTS

Anti-CD22/cal monoclonal antibody (mAb) therapy resulted in early and prolonged B-cell depletion and delayed disease in pre-diabetic mice. Importantly, when new-onset hyperglycemic mice were treated with the anti-CD22/cal mAb, 100% of B-cell-depleted mice became normoglycemic by 2 days, and 70% of them maintained a state of long-term normoglycemia. Early therapy after onset of hyperglycemia and complete B-cell depletion are essential for optimal efficacy. Treated mice showed an increase in percentage of regulatory T-cells in islets and pancreatic lymph nodes and a diminished immune response to islet peptides in vitro. Transcriptome analysis of reemerging B-cells showed significant changes of a set of proinflammatory genes. Functionally, reemerging B-cells failed to present autoantigen and prevented diabetes when cotransferred with autoreactive CD4(+) T-cells into NOD.SCID hosts.

CONCLUSIONS

Targeting CD22 depletes and reprograms B-cells and reverses autoimmune diabetes, thereby providing a blueprint for development of novel therapies to cure autoimmune diabetes.

A common nonsynonymous single nucleotide polymorphism in the SLC30A8 gene determines ZnT8 autoantibody specificity in type 1 diabetes

OBJECTIVE

Zinc transporter eight (SLC30A8) is a major target of autoimmunity in human type 1A diabetes and is implicated in type 2 diabetes in genome-wide association studies. The type 2 diabetes nonsynonymous single nucleotide polymorphism (SNP) affecting aa(325) lies within the region of highest ZnT8 autoantibody (ZnT8A) binding, prompting an investigation of its relationship to type 1 diabetes.

RESEARCH DESIGN AND METHODS

ZnT8A radioimmunoprecipitation assays were performed in 421 new-onset type 1 diabetic Caucasians using COOH-terminal constructs incorporating the known human aa(325) variants (Trp, Arg, and Gln). Genotypes were determined by PCR-based SNP analysis. RESULTS-Sera from 224 subjects (53%) were reactive to Arg(325) probes, from 185 (44%) to Trp(325)probes, and from 142 (34%) to Gln(325)probes. Sixty subjects reacted only with Arg(325) constructs, 31 with Trp(325) only, and 1 with Gln(325) only. The restriction to either Arg(325) or Trp(325) corresponded with inheritance of the respective C- or T-alleles. A strong gene dosage effect was also evident because both Arg- and Trp-restricted ZnT8As were less prevalent in heterozygous than homozygous individuals. The SLC30A8 SNP allele frequency (75% C and 25% T) varied little with age of type 1 diabetes onset or the presence of other autoantibodies.

CONCLUSIONS

The finding that diabetes autoimmunity can be defined by a single polymorphic residue has not previously been documented. It argues against ZnT8 autoimmunity arising from molecular mimicry and suggests a mechanistic link between the two major forms of diabetes. It has implications for antigen-based therapeutic interventions because the response to ZnT8 administration could be protective or immunogenic depending on an individual's genotype.

Impact of diabetes susceptibility loci on progression from pre-diabetes to diabetes in at-risk individuals of the diabetes prevention trial-type 1 (DPT-1)

OBJECTIVE

The unfolding of type 1 diabetes involves a number of steps: defective immunological tolerance, priming of anti-islet autoimmunity, and destruction of insulin-producing beta-cells. A number of genetic loci contribute to susceptibility to type 1 diabetes, but it is unclear which stages of the disease are influenced by the different loci. Here, we analyzed the frequency of type 1 diabetes-risk alleles among individuals from the Diabetes Prevention Trial-Type 1 (DPT-1) clinical trial, which tested a preventive effect of insulin in at-risk relatives of diabetic individuals, all of which presented with autoimmune manifestations but only one-third of which eventually progressed to diabetes.

RESEARCH DESIGN AND METHODS

In this study, 708 individuals randomized into DPT-1 were genotyped for 37 single nucleotide polymorphisms in diabetes susceptibility loci.

RESULTS

Susceptibility alleles at loci expected to influence immunoregulation (PTPN22, CTLA4, and IL2RA) did not differ between progressors and nonprogressors but were elevated in both groups relative to general population frequencies, as was the INS promoter variant. In contrast, HLA DQB1*0302 and DQB1*0301 differed significantly in progressors versus nonprogressors (DQB*0302, 42.6 vs. 34.7%, P = 0.0047; DQB*0301, 8.6 vs. 14.3%, P = 0.0026). Multivariate analysis of the factors contributing to progression demonstrated that initial titers of anti-insulin autoantibodies (IAAs) could account for some (P = 0.0016) but not all of this effect on progression (P = 0.00038 for the independent effect of the number of DQB*0302 alleles). The INS-23 genotype was most strongly associated with anti-IAAs (median IAA levels in TT individuals, 60 nU/ml; AT, 121; and AA, 192; P = 0.000037) and only suggestively to the outcome of oral insulin administration.

CONCLUSIONS

With the exception of HLA, most susceptibility loci tested condition the risk of autoimmunity rather than the risk of failed immunoregulation that results in islet destruction. Future clinical trials might consider genotyping INS-23 in addition to HLA alleles as disease/treatment response modifier.

Role of microRNAs in diabetes

Diabetes is one of the most common chronic diseases in the world. Multiple and complex factors including various genetic and physiological changes can lead to type 1 and type 2 diabetes. However, the major mechanisms underlying the pathogenesis of diabetes remain obscure. With the recent discovery of microRNAs (miRNAs), these small ribonucleotides have been implicated as new players in the pathogenesis of diabetes and diabetes-associated complications. MiRNAs have been shown to regulate insulin production, insulin secretion, and insulin action. This review summarizes the recent progress in the cutting-edge research of miRNAs involved in diabetes and diabetes related complications.