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Objective: In patients with long-standing type 1 diabetes, we investigated whether improved beta-cell function can be achieved by combining intensive insulin therapy with agents that may 1) promote beta-cell growth and/or limit beta-cell apoptosis and 2) weaken the anti-beta-cell autoimmunity.Research Design and Methods: For this study, 20 individuals (mean age 39.5 +/- 11.1 years) with long-standing type 1 diabetes (21.3 +/- 10.7 years) were enrolled in this prospective open-label crossover trial. After achieving optimal blood glucose control, 16 subjects were randomized to exenatide with or without daclizumab. Endogenous insulin production was determined by repeatedly measuring serum C-peptide.Results: In 85% of individuals with long-standing type 1 diabetes who were screened for participation in this trial, C-peptide levels >or=0.05 ng/ml (0.02 nmol/l) were found. Residual beta-cells responded to physiological (mixed-meal) and pharmacological (arginine) stimuli. During exenatide treatment, patients lost 4.1 +/- 2.9 kg body wt and insulin requirements declined significantly (total daily dose on exenatide 0.48 +/- 0.11 vs. 0.55 +/- 0.13 units x kg(-1) x day(-1) without exenatide; P = 0.0062). No signs of further activation of the underlying autoimmune disease were observed. Exenatide delayed gastric emptying, suppressed endogenous incretin levels, but did not increase C-peptide secretion.Conclusions: In long-standing type 1 diabetes, which remains an active autoimmune disease even decades after its onset, surviving beta-cells secrete insulin in a physiologically regulated manner. However, the combination of intensified insulin therapy, exenatide, and daclizumab did not induce improved function of these remaining beta-cells. [ABSTRACT FROM AUTHOR]

Latent autoimmune diabetes in adults or type 1.5 diabetes is considered to be a T-cell-mediated autoimmune disease. However, identification of patients is based commonly on autoantibody (Ab) detection. To determine whether measuring T-cell reactivity to islet proteins compared with measuring Abs improves detection of autoimmune diabetes and how beta-cell function correlates with T-cell reactivity compared with Ab positivity, we assessed the T-cell proliferative responses and Ab responses (islet cell autoantibodies, insulin autoantibodies, insulinoma-associated protein-2 autoantibodies, and GAD Abs) to islet proteins of 36 phenotypic type 2 diabetic patients. To be considered Ab(+) or T-cell(+), patients were required to be positive for a minimum of two consecutive time points. beta-Cell function was measured with fasting and glucagon-stimulated C-peptide. Independent of T-cell reactivity, Ab(+) and Ab(-) patients had comparable fasting and glucagon-stimulated C-peptide. Independent of Ab status, T-cell(+) patients demonstrated significantly lower glucagon-stimulated (P < 0.003) C-peptide compared with T-cell(-) patients. These data suggest that measuring T-cell responses to multiple islet proteins in phenotypic type 2 diabetic patients improves identification of patients with autoimmune diabetes and delineates those who have a more severe beta-cell lesion compared with Ab assessment alone. [ABSTRACT FROM AUTHOR]

Type 1 diabetes is a chronic autoimmune disease mediated by autoreactive T-cells. Several experimental therapies targeting T-cells are in clinical trials. To understand how these therapies affect T-cell responses in vivo, assays that directly measure human T-cell function are needed. In a blinded, multicenter, case-controlled study conducted by the Immune Tolerance Network, we tested responses in an immunoblot and T-cell proliferative assay to distinguish type 1 diabetic patients from healthy control subjects. Peripheral blood cells from 39 healthy control subjects selected for DR4 and 23 subjects with recently diagnosed type 1 diabetes were studied. Autoantibody responses were measured in serum samples. Positive responses in both assays were more common in peripheral blood mononuclear cells from new-onset type 1 diabetic patients compared with control subjects. The proliferative, immunoblot, and autoantibody assays had sensitivities of 58, 91, and 78% with specificities of 94, 83, and 85%, respectively. When cellular assays were combined with autoantibody measurements, the sensitivity of the measurements was 75% with 100% specificity. We conclude that cellular assays performed on peripheral blood have a high degree of accuracy in discriminating responses in subjects with type 1 diabetes from healthy control subjects. They may be useful for assessment of cellular autoimmune responses involved in type 1 diabetes. [ABSTRACT FROM AUTHOR]

Context: Autoantibodies directed against the 65-kilodalton isoform of glutamic acid decarboxylase (GAD65Abs) are markers of autoimmune type 1 diabetes (T1D) but are also present in patients with Latent Autoimmune Diabetes of Adults and autoimmune neuromuscular diseases, and also in healthy individuals. Phenotypic differences between these conditions are reflected in epitope-specific GAD65Abs and anti-idiotypic antibodies (anti-Id) against GAD65Abs. We previously reported that 7.8% of T2D patients in the GRADE study have GAD65Abs but found that GAD65Ab positivity was not correlated with beta-cell function, glycated hemoglobin (HbA1c), or fasting glucose levels., Context: In this study, we aimed to better characterize islet autoantibodies in this T2D cohort. This is an ancillary study to NCT01794143., Methods: We stringently defined GAD65Ab positivity with a competition assay, analyzed GAD65Ab-specific epitopes, and measured GAD65Ab-specific anti-Id in serum., Results: Competition assays confirmed that 5.9% of the patients were GAD65Ab positive, but beta-cell function was not associated with GAD65Ab positivity, GAD65Ab epitope specificity or GAD65Ab-specific anti-Id. GAD65-related autoantibody responses in GRADE T2D patients resemble profiles in healthy individuals (low GAD65Ab titers, presence of a single autoantibody, lack of a distinct epitope pattern, and presence of anti-Id to diabetes-associated GAD65Ab). In this T2D cohort, GAD65Ab positivity is likely unrelated to the pathogenesis of beta-cell dysfunction., Conclusion: Evidence for islet autoimmunity in the pathophysiology of T2D beta-cell dysfunction is growing, but T1D-associated autoantibodies may not accurately reflect the nature of their autoimmune process., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society.)

Type 2 diabetes (T2D) results from insulin secretory dysfunction arising in part from the loss of pancreatic islet β-cells. Several factors contribute to β-cell loss, including islet amyloid formation, which is observed in over 90% of individuals with T2D. The amyloid is comprised of human islet amyloid polypeptide (hIAPP). Here we provide evidence that early in aggregation, hIAPP forms toxic oligomers prior to formation of amyloid fibrils. The toxic oligomers contain α-sheet secondary structure, a nonstandard secondary structure associated with toxic oligomers in other amyloid diseases. De novo, synthetic α-sheet compounds designed to be nontoxic and complementary to the α-sheet structure in the toxic oligomers inhibit hIAPP aggregation and neutralize oligomer-mediated cytotoxicity in cell-based assays. In vivo administration of an α-sheet design to mice for 4 weeks revealed no evidence of toxicity nor did it elicit an immune response. Furthermore, the α-sheet designs reduced endogenous islet amyloid formation and mitigation of amyloid-associated β-cell loss in cultured islets isolated from an hIAPP transgenic mouse model of islet amyloidosis. Characterization of the involvement of α-sheet in early aggregation of hIAPP and oligomer toxicity contributes to elucidation of the molecular mechanisms underlying amyloid-associated β-cell loss., (© 2023 The Protein Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Islet autoimmunity may contribute to β-cell dysfunction in type 2 diabetes (T2D). Its prevalence and clinical significance have not been rigorously determined. In this ancillary study to the Glycemia Reduction Approaches in Diabetes-A Comparative Effectiveness (GRADE) Study, we investigated the prevalence of cellular and humoral islet autoimmunity in patients with T2D duration 4·0±3·0 y, HbA1c 7·5±0·5% on metformin alone. We measured T cell autoreactivity against islet proteins, islet autoantibodies against GAD65, IA2, ZnT8, and β-cell function. Cellular islet autoimmunity was present in 41·3%, humoral islet autoimmunity in 13·5%, and both in 5·3%. β-cell function calculated as iAUC-CG and ΔC-peptide(0- 30)/Δglucose(0-30) from an oral glucose tolerance test was lower among T cell-positives (T+) than T cell-negatives (T-) using two different adjustments for insulin sensitivity (iAUC-CG: 13·2% [95% CI 0·3, 24·4%] or 11·4% [95% CI 0·4, 21·2%] lower; ΔC-peptide(0-30)/Δglucose(0-30)) 19% [95% CI 3·1, 32·3%] or 17·7% [95% CI 2·6, 30·5%] lower). T+ patients had 17% higher HbA1c (95% CI 0·07, 0·28) and 7·7 mg/dL higher fasting plasma glucose levels (95% CI 0·2,15·3) than T- patients. We conclude that islet autoimmunity is much more prevalent in T2D patients than previously reported. T cell-mediated autoimmunity is associated with diminished β-cell function and worse glycemic control., (© 2022 by the American Diabetes Association.)

Thiol lysolipids undergo thiol-thioester exchange with two phenyl thioester-functionalized tails to produce phospholipid structures that assemble into liposomes with differences in exchange rates, temperature sensitivity, permeability, and continued exchange behavior. This in situ formation reaction imparts dynamic characteristics into the membrane for downstream liposome functionalization and mimics native membrane remodeling.

Type 1 diabetes (T1D) is a cell-mediated autoimmune disease. New cases of T1D are on the increase and exogenous insulin therapy is the only intervention regularly initiated for T1D patients. Though tremendous strides have been made in prediction of T1D, prevention and intervention strategies have not experienced the same success. In this review, we will discuss some possible reasons why new intervention therapies for T1D have not been implemented into the mainstream treatment regimen for T1D patients. We will also discuss potential caveats for why prevention and intervention trials in T1D may not have experienced the same success as prediction trials., (Copyright © 2013 Elsevier Inc. All rights reserved.)

In human islet transplantation, insulin independence decreases over time. We previously showed that amyloid deposition following transplantation of islets from human islet amyloid polypeptide (hIAPP) transgenic mice resulted in ß-cell loss and that rosiglitazone treatment decreased islet amyloid deposition and preserved ß-cell area in the endogenous pancreas of hIAPP transgenic mice. Thus, we sought to determine if rosiglitazone treatment decreases islet amyloid deposition and the associated ß-cell loss after islet transplantation. Streptozocin-diabetic mice were transplanted with 100 islets from hIAPP transgenic (T) mice or nontransgenic (NT) littermates under the kidney capsule and received either rosiglitazone (R) in drinking water or plain drinking water (C). The resultant groups (NTC [n = 11], NTR [n = 9], TC [n = 14], and TR [n = 10]) were followed for 12 weeks after which the graft was removed and processed for histology. Amyloid was detected in nearly all T islet grafts (TC = 13/14, TR = 10/10) but not in NT grafts. Rosiglitazone did not alter amyloid deposition (% graft area occupied by amyloid; TC: 2.15 ± 0.7, TR: 1.72 ± 0.66; P = .86). % ß-cell/graft area was decreased in the TC grafts compared to NTC (56.2 ± 3.1 vs 73.8 ± 1.4; P < .0001) but was not different between TC and TR groups (56.2 ± 3.1 vs 61.0 ± 2.9; P = .34). Plasma glucose levels before and after transplantation did not differ between NTC and TC groups and rosiglitazone did not affect plasma glucose levels post-islet transplantation. Rosiglitazone did not decrease amyloid deposition in hIAPP transgenic islet grafts. Therefore, rosiglitazone treatment of recipients of amyloid forming islets may not improve transplantation outcomes., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Recent advances in understanding the etiology of obesity, metabolic syndrome, and type 2 diabetes (T2D) have established involvement of the immune system. These developments highlight the potential of immunomodulatory therapies for treatment of these conditions. Here, we discuss current and new immunotherapeutic strategies for the treatment of T2D, the need for stratification of patients based on immune and autoimmune status, and biomarkers for evaluating treatment efficiency. The time has come to re-evaluate the clinical management of T2D patients using metabolic parameters alone, and to realize that patients should be stratified based on their immune and/or autoimmune status prior to initiation of therapy to realize fully the potential of immunomodulatory strategies for T2D., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The diabetes prevention trial-type 1 (DPT-1) tested whether a combination of SQ and IV insulin therapy would delay the onset of disease in individuals at high risk of progression. We investigated whether this regimen altered T cell responses to human islet proteins using cellular immunoblotting. Among the 10 treated and 7 control subjects studied, we found that there was a significant effect of treatment on cellular immunoblotting responses. We conclude that parenteral insulin may suppress proliferation to islet antigens in individuals at risk for diabetes, but this effect may be transient. Further study is needed to determine whether a therapy that results in sustained suppression of T cell proliferation could yield a measurable clinical benefit., (© 2010 John Wiley & Sons A/S.)

Background: Diabetes mellitus has been historically divided into type 1 and type 2 diabetes, with type 1 being an autoimmune disease and type 2 being primarily a metabolic disease., Content: The current diabetes classification scheme needs to be reevaluated because of the accumulating evidence of immune system involvement in the pathophysiology of type 2 diabetes., Summary: There are similarities and differences between type 1 and type 2 diabetes with regard to pathogenesis, pathophysiology, and genetics. We propose a resolution to the dilemma of the current classification scheme.

Objective: Type 1 diabetes results from an immunemediated destruction of beta-cells, likely to be mediated by T lymphocytes, but the sensitivity, specificity, and other measures of validity of existing assays for islet autoreactive T-cells are not well established. Such assays are vital for monitoring responses to interventions that may modulate disease progression., Research Design and Methods: We studied the ability of cellular assays to discriminate responses in patients with type 1 diabetes and normal control subjects in a randomized blinded study in the U.S. and U.K. We evaluated the reproducibility of these measurements overall and to individual analytes from repeat collections., Results: Responses in the cellular immunoblot, U.K.-ELISPOT, and T-cell proliferation assays could differentiate patients from control subjects with odds ratios of 21.7, 3.44, and 3.36, respectively, with sensitivity and specificity as high as 74 and 88%. The class II tetramer and U.S. ELISPOT assays performed less well. Despite the significant association of the responses with type 1 diabetes, the reproducibility of the measured responses, both overall and individual analytes, was relatively low. Positive samples from normal control subjects (i.e., false positives) were generally isolated to single assays., Conclusions: The cellular immunoblot, U.K.-ELISPOT, and T-cell proliferation assays can distinguish responses from patients with type 1 diabetes and healthy control subjects. The limited reproducibility of the measurements overall and of responses to individual analytes may reflect the difficulty in detection of low frequency of antigen-specific T-cells or variability in their appearance in peripheral blood.

Diabetes mellitus is comprised primarily of two clinically separate diseases: type 1 (T1D) and type 2 diabetes (T2D). T1D is a cell-mediated autoimmune disease directed against the beta cells and characterized by autoantibody (Ab) and T cell reactivity to islet proteins whereas, T2D is non-autoimmune. Despite the fact that the pathological process in autoimmune diabetes involves T cells, immune markers of diabetes have primarily centered on the presence of circulating serum islet autoantibodies. In two masked NIH sponsored workshops, our cellular immunoblotting T cell assay, which uses isolated human islets separated into 18 molecular weight fractions, has been validated to be able to distinguish T1D patients from controls with excellent specificity and sensitivity. In this study, we utilized the first workshop to select eight molecular weight fractions of human islets that were the most discriminatory between T1D patients and controls. Using these eight molecular weight fractions identified in the first workshop, we validated the preferential recognition of these 8 blot sections in a second workshop. We then re-calculated the sensitivity and specificity of the cellular immunoblotting assay for both workshops using only the data from these 8 blot sections.We observed increases in both sensitivity and specificity compared to the original workshop data for both workshops. The use of 8 instead of 18 molecular weight regions allows for a significant reduction in the amount of blood needed from patients, thus allowing cellular immunoblotting to be performed on pediatric patients participating in immunomodulatory studies. This improved T cell assay, which directly measures islet reactive T cell responses in autoimmune diabetes patients with excellent sensitivity and specificity, will likely improve patient follow-up during intervention studies.

Insulin resistance is a primary component in the pathophysiology of type 2 diabetes. In latent autoimmune diabetes in adults (LADA), insulin resistance has been reported to be significantly lower than in autoantibody-negative type 2 diabetes (T2DM), but whether this might be related to differences in body mass index (BMI) has not been excluded. Furthermore, previous studies have used limiting inclusive criteria for LADA, requiring only the presence of GADA or IA-2A. To apply more inclusive criteria for LADA, consistent with recent recommendations, we defined LADA by clinical manifestations characteristic of T2DM, but with the presence of any combination of GADA, IA-2A, ICA, or IAA. We recruited 43 LADA patients, 70 T2DM patients, and 150 non-diabetic controls. Insulin resistance was assessed by both the homeostasis model assessment and the quantitative insulin sensitivity check index, and BMI was calculated. We found that insulin resistance in LADA is equivalent to that of T2DM. When insulin resistance is assessed as a function of BMI, both diabetic populations demonstrated an insulin resistance equally greater than normal controls. The interaction between insulin resistance and BMI in the two diabetic groups was significantly different from that demonstrated in non-diabetic controls. In summary, LADA demonstrates insulin resistance of similar magnitude to T2DM, but with the concurrent component of an immune attack against the pancreatic beta-cells. LADA patients may be at significant risk for metabolic consequences of insulin resistance other than glucose metabolism, such as those described in the metabolic syndrome. As complications and treatment regimens specific to LADA are realized, improved means of identification of LADA will become increasingly important.

T-cell mediated autoimmune beta-cell destruction is an important component of type 1 diabetes (T1D) and insulin is a critical antigen recognized by autoreactive T-cells. The aim of this study was to investigate the precursor frequency of insulin reactive T-cells in type 1 diabetes. We studied 19 T1D patients, 12 age-matching non-diabetic healthy siblings and 12 non-diabetic healthy parents. Limiting dilution analysis (LDA) was performed to insulin and tetanus toxoid (TT). A progressive decrease in the number of negative cultures at increasing cell concentrations that is represented by a low goodness-of-fit (GoF, low Chi-square), was seen with the TT response in all three groups; precursor frequencies and GoF were similar in patients, siblings, and parents. Reactivity to insulin, however, showed low precursor frequencies in patients and siblings and the LDA to insulin demonstrated dramatic decreases in the number of positive cultures at higher cell concentrations leading to a high GoF in patients and siblings compared to parents. This saw-toothed pattern of reactivity to insulin is indicative of multiple hit kinetics and implies that the response is regulated. Consequently the precursor frequency of insulin autoreactive cells in patients and their siblings is probably much higher than calculated., (Copyright 2004 Elsevier Ltd.)