GAD antibody positivity predicts type 2 diabetes in an adult population

A Randomized Trial of Automated Insulin Delivery in Type 2 Diabetes

BACKGROUND

Automated insulin delivery (AID) systems have been shown to be beneficial for patients with type 1 diabetes, but data are needed from randomized, controlled trials regarding their role in the management of insulin-treated type 2 diabetes.

METHODS

In this 13-week, multicenter trial, adults with insulin-treated type 2 diabetes were randomly assigned in a 2:1 ratio to receive AID or to continue their pretrial insulin-delivery method (control group); both groups received continuous glucose monitoring (CGM). The primary outcome was the glycated hemoglobin level at 13 weeks.

RESULTS

A total of 319 patients underwent randomization. Glycated hemoglobin levels decreased by 0.9 percentage points (from 8.2±1.4% at baseline to 7.3±0.9% at week 13) in the AID group and by 0.3 percentage points (from 8.1±1.2% to 7.7±1.1%) in the control group (mean adjusted difference, -0.6 percentage points; 95% confidence interval [CI], -0.8 to -0.4; P<0.001). The mean percentage of time that patients were in the target glucose range of 70 to 180 mg per deciliter increased from 48±24% to 64±16% in the AID group and from 51±21% to 52±21% in the control group (mean difference, 14 percentage points; 95% CI, 11 to 17; P<0.001). All other multiplicity-controlled CGM outcomes reflective of hyperglycemia that were measured were significantly better in the AID group than in the control group. The frequency of CGM-measured hypoglycemia was low in both groups. A severe hypoglycemia event occurred in one patient in the AID group.

CONCLUSIONS

In this 13-week, randomized, controlled trial involving adults with insulin-treated type 2 diabetes, AID was associated with a greater reduction in glycated hemoglobin levels than CGM alone. (Funded by Tandem Diabetes Care; 2IQP ClinicalTrials.gov number, NCT05785832.).

A Review on Latent Autoimmune Diabetes in Adults

Latent autoimmune diabetes (LADA) is an unique form of diabetes that has characteristics of both type 1 and type 2 diabetes. Type 1.5 diabetes also known as LADA is occasionally confused for type 2 diabetes because there is delay in presenting features and early insulin independence. LADA, on the other hand, is an autoimmune disorder that differs from type 2 diabetes in that autoantibodies against pancreatic beta cells are what characterise it. Insulin production eventually diminishes due to the autoimmune destruction of pancreatic beta cells as a result of the pathophysiology of LADA. Autoantibodies to glutamic acid decarboxylase (GAD), islet antigen-2 (IA-2), and insulin are frequently detected in LADA patients. These autoantibodies have important implications for therapy strategies and are essential in differentiating LADA from type 2 diabetes. LADA clinical management is very challenging. The aim of this article is to view the characteristics, disease presentation, diagnostic challenges, progression and treatment modalities of LADA.

Serum and salivary adiponectin levels as predictive markers for diabetes mellitus in children with a family history of diabetes

Diabetes mellitus (DM) is a chronic, metabolic condition marked by defects in insulin production, action, or both. Environmental and genetic factors can contribute to the onset of diabetes mellitus. Adiponectin, a hormone affecting pancreatic beta cell proliferation, has emerged as a potential indicator of diabetes risk. This cross-sectional study aimed to evaluate serum and salivary adiponectin levels as predictors of diabetes mellitus in children with/without a family history of diabetes mellitus. The study was conducted at Al-Zahra Hospital in Najaf city and included 125 children aged 5 to 16. Data on demographics, including name, age, and gender, were collected, and body mass index (BMI) was assessed. Serum and salivary adiponectin levels were measured and analyzed in relation to family history and BMI. Children with a family history of DM had high serum adiponectin (ADP) levels. Serum adiponectin levels were significantly higher in children with first-degree relatives having a history of diabetes mellitus, except for cases involving mothers and other relatives with diabetes mellitus history (p<0.05). Furthermore, serum adiponectin levels were higher in obese children. Salivary adiponectin levels were significantly elevated in children with a maternal family history of diabetes (p=0.01), while no significant correlation was found with BMI. A significant negative correlation (r=-0.180, p=0.05) between salivary and serum adiponectin concentrations was observed. Compared to children with a normal, healthy weight, children with obesity had decreased salivary adiponectin levels and increased serum adiponectin levels.

Determination of autoantibodies in type 2 diabetes: one simple way to improve classification

This letter aims to increase interest in better classification of type 2 diabetes. This can be done in a simple and cheap way via determination of autoantibodies. Autoantibody analysis can be used to detect the 7-12% of people with diabetes that is phenotypic of type 2 diabetes but is, in fact, latent autoimmune diabetes in adults (LADA), which may be regarded as a variant of type 1 diabetes. This may help to explain why some individuals with type 2 diabetes do not go into remission after reducing their weight, while others do, and why remission sometimes ends earlier than expected. Improved classification of diabetes may play an important role in determining adequate therapy.

Prevalence and factors associated with latent autoimmune diabetes in adults (LADA): a cross-sectional study

BACKGROUND

The Latent Autoimmune Diabetes in Adults (LADA) is a slowly progressive Type 1 diabetes subgroup with onset during middle age. Studies report that about 10% of adults initially diagnosed with clinical Type 2 diabetes (T2D) have LADA. Inappropriate diagnosis and mismanagement of the LADA can increase the risk of diabetic complications, which affect the quality of life and is the cause of increased mortality. In low-income countries setting, data regarding the magnitude of LADA is limited. We carried out this study to estimate the burden of misdiagnosed LADA among T2D patients in selected health facilities in Dar es Salaam and to bring awareness to the use of Glutamic Acid Decarboxylase (GAD) autoantibody in screening for LADA.

METHODOLOGY

We enrolled 186 phenotypically T2D patients in this cross-sectional study, through a standardized data collection tool we obtained participants' demographic and clinical information. For testing GAD levels, we used a double-antibody Enzyme-Linked Immunosorbent Assay (ELISA). The Fisher's Exact and student t-tests were used to test the significance of the statistical associations of the glycaemic control and diabetes complications between T2D and LADA.

RESULTS

Out of 186 patients, 156 gave conclusive GAD Ab ELISA reading with LADA accounting for 5.1% (95% CI: 2.5 - 10.0). The mean age of subjects was 54.3 years (Range: 33-85 years). The parameters such as mean age, family history of diabetes mellitus status, Fasting Blood Glucose, clinical characteristics, and complications did not show significant statistical differences between patients with LADA and Type 2 diabetes. However, all LADA- Human Immunodeficiency Virus (HIV) comorbid patients had retinopathy, which was statistically insignificant in 20 (87%) T2D-HIV comorbid patients (p = 0.669). Neither neuropathy, nephropathy, nor Diabetic Mellitus (D.M.) foot syndrome was observed among LADA-HIV comorbid patients. Nevertheless, 22 (95.7%), 3 (13%), and 2 (8.7%) of T2D-HIV comorbidity had neuropathy, nephropathy, or D.M. foot syndrome, respectively.

CONCLUSIONS

The study established a LADA prevalence of 5.1% among T2D patients and has shown the role of GAD autoantibody in the screening for LADA. The study calls for a well- designed larger longitudinal study to generate strong evidence on the association of risk factors and complications associated with the LADA. This will develop robust evidence on the association of risk factors and complications associated with the LADA and T2D.

Lifestyle or Environmental Influences and Their Interaction With Genetic Susceptibility on the Risk of LADA

Background

LADA is a common form of diabetes described as a mix between type 1 and type 2 diabetes. Understanding of how genes and environmental factors interact in the development of LADA is central for future efforts to prevent the disease. This review aims to synthesize the literature on lifestyle factors linked to LADA risk and discuss their potential interaction with genetic susceptibility.

Findings

Current knowledge on environmental risk factors for LADA is primarily based on observational data from Scandinavian populations. Increasing evidence suggest that lifestyle factors promoting type 2 diabetes such as obesity, sedentariness, low birth weight and smoking, is implicated in the risk of LADA. Data from mendelian randomization studies support that the link between LADA and obesity, low birth weight and smoking is causal. Limited evidence indicates that dietary factors including consumption of red meat, coffee and sweetened beverages may increase the risk while consumption of alcohol and omega-3 fatty acids may reduce the risk. Several lifestyle factors, including smoking and obesity, seem to interact with human leukocyte antigen genes associated with autoimmunity, conferring much stronger effects on disease risk among those exposed to both factors.

Summary

Available studies suggest that lifestyle modification has the potential for prevention of LADA, particularly for individuals with high risk of disease such as those with genetic susceptibility. Research into risk factors of LADA is however limited, confirmations are warranted, many factors remain to be explored, and there is a need for intervention studies to assess causality.

Alterations in Biomarkers Related to Glycemia, Lipid Metabolism, and Inflammation up to 20 Years Before Diagnosis of Type 1 Diabetes in Adults: Findings From the AMORIS Cohort

OBJECTIVE

Type 1 diabetes is described to have an acute onset, but autoantibodies can appear several years preceding diagnosis. This suggests a long preclinical phase, which may also include metabolic parameters. Here we assessed whether elevations in glycemic, lipid, and other metabolic biomarkers were associated with future type 1 diabetes risk in adults.

RESEARCH DESIGN AND METHODS

We studied 591,239 individuals from the Swedish AMORIS cohort followed from 1985-1996 to 2012. Through linkage to national patient, diabetes, and prescription registers, we identified incident type 1 diabetes. Using Cox regression models, we estimated hazard ratios for biomarkers at baseline and incident type 1 diabetes. We additionally assessed trajectories of biomarkers during the 25 years before type 1 diabetes diagnosis in a nested case-control design.

RESULTS

We identified 1,122 type 1 diabetes cases during follow-up (average age of patient at diagnosis: 53.3 years). The biomarkers glucose, fructosamine, triglycerides, the ratio of apolipoprotein (apo)B to apoA-I, uric acid, alkaline phosphatase, and BMI were positively associated with type 1 diabetes risk. Higher apoA-I was associated with lower type 1 diabetes incidence. Already 15 years before diagnosis, type 1 diabetes cases had higher mean glucose, fructosamine, triglycerides, and uric acid levels compared with control subjects.

CONCLUSIONS

Alterations in biomarker levels related to glycemia, lipid metabolism, and inflammation are associated with clinically diagnosed type 1 diabetes risk, and these may be elevated many years preceding diagnosis.

The role of autoimmunity in the pathophysiology of type 2 diabetes: Looking at the other side of the moon

Efforts to unravel the pathophysiological mechanisms of type 2 diabetes (T2D) have been traditionally trapped into a metabolic perspective. However, T2D is a phenotypically and pathophysiologically heterogenous disorder, and the need for a tailored approach in its management is becoming increasingly evident. There is emerging evidence that irregular immune responses contribute to the development of hyperglycemia in T2D and, inversely, that insulin resistance is a component of the pathogenesis of autoimmune diabetes. Nevertheless, it has not yet been fully elucidated to what extent the presence of conventional autoimmune markers, such as autoantibodies, in subjects with T2D might affect the natural history of the disease and particularly each response to various treatments. The challenge for future research in the field is the discovery of novel genetic, molecular, or phenotypical indicators that would enable the characterization of specific subpopulations of people with T2D who would benefit most from the addition of immunomodulatory therapies to standard glucose-lowering treatment. This narrative review aims to discuss the plausible mechanisms through which the immune system might be implicated in the development of metabolic disturbances in T2D and obesity and explore a potential role of immunotherapy in the future management of the disorder and its complications.

Family history of type 2 diabetes and characteristics of children with newly diagnosed type 1 diabetes

AIMS/HYPOTHESIS

Shared aetiopathogenetic factors have been proposed in type 1 diabetes and type 2 diabetes and both diseases have been shown to cluster in families. Characteristics related to type 2 diabetes have been described in patients with type 1 diabetes with a positive family history of type 2 diabetes. We wanted to characterise the family history of type 2 diabetes and its possible effects on the phenotype and genotype of type 1 diabetes in affected children at diagnosis.

METHODS

A total of 4993 children under the age of 15 years with newly diagnosed type 1 diabetes from the Finnish Pediatric Diabetes Register were recruited (56.6% boys, median age of 8.2 years) for a cross-sectional, observational, population-based investigation. The family history of diabetes at diagnosis was determined by a structured questionnaire, and markers of metabolic derangement, autoantibodies and HLA class II genetics at diagnosis were analysed.

RESULTS

Two per cent of the children had an immediate family member and 36% had grandparents with type 2 diabetes. Fathers and grandfathers were affected by type 2 diabetes more often than mothers and grandmothers. The children with a positive family history for type 2 diabetes were older at the diagnosis of type 1 diabetes (p < 0.001), had higher BMI-for-age (p = 0.01) and more often tested negative for all diabetes-related autoantibodies (p = 0.02).

CONCLUSIONS/INTERPRETATION

Features associated with type 2 diabetes, such as higher body weight, older age at diagnosis and autoantibody negativity, are more frequently already present at the diagnosis of type 1 diabetes in children with a positive family history of type 2 diabetes.

Predictive Value of GAD Antibody for Diabetes in Normal Chinese Adults: A Retrospective Cohort Study in China

PURPOSE

To investigate the prevalence of GAD antibody (GADA) in the general adult population and to evaluate its predictive value for diabetes in China.

PATIENTS AND METHODS

We searched the PUMCH-HM database and identified 36,731 adult subjects with GADA test results from 2012 to 2015. We then established a retrospective cohort of 4835 nondiabetic subjects at baseline with complete annual health evaluation records through 2019. The median follow-up time was 4.8 (3.0-7.3) years.

RESULTS

The overall prevalence of GADA was 0.53% and was higher in diabetic subjects (1.25%) than in nondiabetic subjects (0.47%). We found a decrease in baseline body mass index (BMI) from the GADA- to GADA_high subgroups among baseline diabetic and prediabetic patients and also those who developed diabetes later in the cohort study. A total of 136 subjects (2.8%) developed diabetes after a median follow-up of 3.5 years. For GADA⁺ participants, BMI was not associated with the risk for diabetes. In the Cox regression model, the GADA_low and GADA_high exhibited 2.63-fold and 4.16-fold increased risk for diabetes, respectively. This increased risk for diabetes by GADA-positivity is only found in male adults (HR 4.55, 95% CI 2.25-9.23).

CONCLUSION

GADA has a low prevalence in China but is associated with a 2.63-4.16-fold increased risk for diabetes.

Characterization of patients with diabetes who were incidentally found to be glutamic acid decarboxylase autoantibody-positive by bridging-type enzyme-linked immunosorbent assay

This study aimed to characterize diabetic patients incidentally found to be positive for glutamic acid decarboxylase autoantibodies (GADA) in general practice. Using bridging‐type enzyme‐linked immunosorbent assay, we screened 1,040 patients with phenotypic type 2 diabetes for GADA, finding 25 (2.4%) to be positive. However, on retesting, with a median interval of 19 days, 44% of GADA‐positive patients turned negative (Disappearing Group). The mean age at diabetes onset was significantly higher (P < 0.05) and GADA titers at first determination were significantly lower (P < 0.001) in the Disappearing Group compared with the Persistent Positive Group. On initial screening, all patients in the Disappearing Group had GADA titers of <6.5 U/mL. The current study showed that a portion of phenotypic type 2 diabetic patients incidentally identified as GADA‐positive were falsely positive, and that to avoid the misclassification, remeasurement of GADA is essential in cases showing very low titers.

Management of Latent Autoimmune Diabetes in Adults: A Consensus Statement From an International Expert Panel

A substantial proportion of patients with adult-onset diabetes share features of both type 1 diabetes (T1D) and type 2 diabetes (T2D). These individuals, at diagnosis, clinically resemble T2D patients by not requiring insulin treatment, yet they have immunogenetic markers associated with T1D. Such a slowly evolving form of autoimmune diabetes, described as latent autoimmune diabetes of adults (LADA), accounts for 2-12% of all patients with adult-onset diabetes, though they show considerable variability according to their demographics and mode of ascertainment. While therapeutic strategies aim for metabolic control and preservation of residual insulin secretory capacity, endotype heterogeneity within LADA implies a personalized approach to treatment. Faced with a paucity of large-scale clinical trials in LADA, an expert panel reviewed data and delineated one therapeutic approach. Building on the 2020 American Diabetes Association (ADA)/European Association for the Study of Diabetes (EASD) consensus for T2D and heterogeneity within autoimmune diabetes, we propose "deviations" for LADA from those guidelines. Within LADA, C-peptide values, proxy for β-cell function, drive therapeutic decisions. Three broad categories of random C-peptide levels were introduced by the panel: 1) C-peptide levels <0.3 nmol/L: a multiple-insulin regimen recommended as for T1D; 2) C-peptide values ≥0.3 and ≤0.7 nmol/L: defined by the panel as a "gray area" in which a modified ADA/EASD algorithm for T2D is recommended; consider insulin in combination with other therapies to modulate β-cell failure and limit diabetic complications; 3) C-peptide values >0.7 nmol/L: suggests a modified ADA/EASD algorithm as for T2D but allowing for the potentially progressive nature of LADA by monitoring C-peptide to adjust treatment. The panel concluded by advising general screening for LADA in newly diagnosed non-insulin-requiring diabetes and, importantly, that large randomized clinical trials are warranted.

Autoimmunity plays a role in the onset of diabetes after 40 years of age

AIMS/HYPOTHESIS

Type 1 and type 2 diabetes differ with respect to pathophysiological factors such as beta cell function, insulin resistance and phenotypic appearance, but there may be overlap between the two forms of diabetes. However, there are relatively few prospective studies that have characterised the relationship between autoimmunity and incident diabetes. We investigated associations of antibodies against the 65 kDa isoform of GAD (GAD65) with type 1 diabetes and type 2 diabetes genetic risk scores and incident diabetes in adults in European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct, a case-cohort study nested in the EPIC cohort.

METHODS

GAD65 antibodies were analysed in EPIC participants (over 40 years of age and free of known diabetes at baseline) by radioligand binding assay in a random subcohort (n = 15,802) and in incident diabetes cases (n = 11,981). Type 1 diabetes and type 2 diabetes genetic risk scores were calculated. Associations between GAD65 antibodies and incident diabetes were estimated using Prentice-weighted Cox regression.

RESULTS

GAD65 antibody positivity at baseline was associated with development of diabetes during a median follow-up time of 10.9 years (HR for GAD65 antibody positive vs negative 1.78; 95% CI 1.43, 2.20) after adjustment for sex, centre, physical activity, smoking status and education. The genetic risk score for type 1 diabetes but not type 2 diabetes was associated with GAD65 antibody positivity in both the subcohort (OR per SD genetic risk 1.24; 95% CI 1.03, 1.50) and incident cases (OR 1.97; 95% CI 1.72, 2.26) after adjusting for age and sex. The risk of incident diabetes in those in the top tertile of the type 1 diabetes genetic risk score who were also GAD65 antibody positive was 3.23 (95% CI 2.10, 4.97) compared with all other individuals, suggesting that 1.8% of incident diabetes in adults was attributable to this combination of risk factors.

CONCLUSIONS/INTERPRETATION

Our study indicates that incident diabetes in adults has an element of autoimmune aetiology. Thus, there might be a reason to re-evaluate the present subclassification of diabetes in adulthood.

Allostasis and the origins of adult-onset diabetes

Physiological plasticity enables homeostasis to be maintained in biological systems, but when such allostasis fails, then disease can develop. In a new population-based study by Rolandsson et al (https://doi.org/10.1007/s00125-019-05016-3), autoimmunity, defined by an immunogenotype, predicted adult-onset non-insulin requiring diabetes. Type 1 diabetes is no longer viewed as a disease confined to children, with a significant proportion, maybe the majority, presenting in adulthood. Such cases masquerade as type 2 diabetes and their identification has clinical utility. Nevertheless, in this study, autoimmunity had a limited effect on the overall risk of adults developing diabetes.

The association between GAD65 antibody levels and incident Type 2 Diabetes Mellitus in an adult population: A meta-analysis

CONTEXT

Antibodies to the 65 kD isoform of glutamic acid decarboxylase (GAD65) have been associated with incident Type 2 Diabetes Mellitus, however results are inconsistent.

OBJECTIVE

To assess the association between GAD65 antibody positivity and incident Type 2 Diabetes Mellitus in a non-diabetic adult (≥18 years) population, in a systematic review and meta-analysis.

DATA SOURCES

A systematic literature search was conducted in Pubmed (MEDLINE) and Embase until January 14th, 2019.

STUDY SELECTION

Included studies were 1) prospective studies on the association between GAD65 antibodies and incident Type 2 Diabetes Mellitus; 2) in a non-diabetic adult (≥18 years) population. To strengthen the review, unpublished data from 1302 Hoorn Study participants were included.

DATA EXTRACTION

Data extraction and quality assessment were performed independently by two observers. Ten studies were rated for methodological quality and seven were pooled using a random-effects meta-analysis, of which 2 strong, 2 moderate and 3 of low methodological quality.

DATA SYNTHESIS

The pooled risk estimate of incident Type 2 Diabetes Mellitus for GAD65 antibody positivity, compared to GAD65 antibody negativity was 3.36 (95% CI: 1.9-5.9). This result was robust to sensitivity analyses. Heterogeneity between studies was significant with I² statistic of 79% (p < 0.0001). However, excluding one study showed a decrease of I² to 19% (p < 0.0001), explaining a large part of the heterogeneity.

CONCLUSION

GAD65 antibody positivity was associated with an increased risk of future Type 2 Diabetes Mellitus in adults.

Etiology and Pathogenesis of Latent Autoimmune Diabetes in Adults (LADA) Compared to Type 2 Diabetes

As the heterogeneity of diabetes is becoming increasingly clear, opportunities arise for more accurate assessment of factors influencing disease onset, which may lead to more efficient primary prevention. LADA - latent autoimmune diabetes in adults - is a common, hybrid form of diabetes with features of both type 1 and type 2 diabetes. This review aims to summarize current knowledge on the pathophysiological and etiological overlap and differences between LADA and type 2 diabetes, discuss similarities between LADA and type 1 diabetes and point at future research needs. Studies conducted to date show a clear genetic overlap between LADA and type 1 diabetes with a high risk conferred by variants in the human leukocyte antigen (HLA) region. In contrast, data from the limited number of studies on lifestyle factors available indicate that LADA may share several environmental risk factors with type 2 diabetes including overweight, physical inactivity, alcohol consumption (protective) and smoking. These factors are known to influence insulin sensitivity, suggesting that insulin resistance, in addition to insulin deficiency due to autoimmune destruction of the beta cells, may play a key role in the pathogenesis of LADA. Moreover, this implies that onset of LADA, similar to type 2 diabetes, to some extent could be prevented or postponed by lifestyle modification such as weight reduction and increased physical activity. The preventive potential of LADA is an important topic to elucidate in future studies, preferably intervention studies.

Genetic Aspects of Latent Autoimmune Diabetes in Adults: A Mini-Review

Diabetes is a multifactorial disease, caused by a complex interplay between environmental and genetic risk factors. Genetic determinants of particularly Type 1 Diabetes (T1D) and Type 2 Diabetes (T2D) have been studied extensively, whereas well-powered studies of Latent Autoimmune Diabetes in Adults (LADA) are lacking. So far available studies support a clear genetic overlap between LADA and T1D, however, with smaller effect sizes of the T1D-risk variants in LADA as compared to T1D. A genetic overlap between LADA and T2D is less clear. However, recent studies, including large numbers of LADA patients, provide different lines of evidence to support a genetic overlap between T2D and LADA. The genetic predisposition to LADA is yet to be explored in a study design, like a genome- wide association study, which allows for analyses of the genetic predisposition independently of prior hypothesis about potential candidate genes. This type of study may facilitate the discovery of risk variants associated with LADA independently of T1D and T2D, and is central in order to determine if LADA should be considered as an independent diabetic subtype. Extended knowledge about the genetic predisposition to LADA may also facilitate stratification of the heterogeneous group of LADA patients, which may assist the choice of treatment. This mini-review summarizes current knowledge of the genetics of LADA, and discusses the perspectives for future studies.

Type 1 Diabetes-related Autoantibodies in Different Forms of Diabetes

Autoantibodies against Glutamic Acid Decarboxylase (GADA), insulinoma antigen-2 (IA- 2A), insulin (IAA) and the most recently Zinc Transporter 8 (ZnT8A) are one of the most reliable biomarkers for autoimmune diabetes in both children and adults. They are today the only biomarkers that can distinguish Latent Autoimmune Diabetes in Adults (LADA) from phenotypically type 2 diabetes. As the frequency of autoantibodies at diagnosis in childhood type 1 diabetes depends on age, GADA is by far the most common in adult onset autoimmune diabetes, especially LADA. Being multiple autoantibody positive have also shown to be more common in childhood diabetes compared to adult onset diabetes, and multiple autoantibody positivity have a high predictive value of childhood type 1 diabetes. Autoantibodies have shown inconsistent results to predict diabetes in adults. Levels of autoantibodies are reported to cause heterogeneity in LADA. Reports indicate that individuals with high levels of autoantibodies have a more type 1 diabetes like phenotype and individuals with low levels of autoantibody positivity have a more type 2 diabetes like phenotype. It is also well known that autoantibody levels can fluctuate and transient autoantibody positivity in adult onset autoimmune diabetes have been reported to affect the phenotype.

Immunological markers as predictors of developing steroid-induced diabetes mellitus in pemphigus vulgaris patients: An observational study

The aim of this study was to evaluate the clinical importance of autoantibodies in pemphigus vulgaris patients who developed steroid-induced diabetes mellitus (SID) because of the glucocorticoid therapy of pemphigus.A total of 137 patients with pemphigus vulgaris were studied. Patients with SID and pemphigus were compared with those that had only pemphigus. The variables recorded were: age at diagnosis, sex, body mass index, presence of diabetes mellitus (DM), cumulative cortisone dose, treatment duration, value of anti-desmoglein 1 and 3, and anti-glutamic acid decarboxylase autoantibodies.A total of 31 patients (22.62%) that developed steroid-induced DM were identified. Anti-glutamic acid decarboxylase autoantibodies were positive in 20.75% of patients with pemphigus vulgaris and in 25.75% of patients with pemphigus vulgaris and SID.The overall anti-glutamic acid decarboxylase autoantibodies prevalence in pemphigus patients was high, and the risk of developing DM in patients with pemphigus remains a serious problem, being associated with increased risk of mortality.

HAPT2D: high accuracy of prediction of T2D with a model combining basic and advanced data depending on availability

OBJECTIVE

Type 2 diabetes arises from the interaction of physiological and lifestyle risk factors. Our objective was to develop a model for predicting the risk of T2D, which could use various amounts of background information.

RESEARCH DESIGN AND METHODS

We trained a survival analysis model on 8483 people from three large Finnish and Spanish data sets, to predict the time until incident T2D. All studies included anthropometric data, fasting laboratory values, an oral glucose tolerance test (OGTT) and information on co-morbidities and lifestyle habits. The variables were grouped into three sets reflecting different degrees of information availability. Scenario 1 included background and anthropometric information; Scenario 2 added routine laboratory tests; Scenario 3 also added results from an OGTT. Predictive performance of these models was compared with FINDRISC and Framingham risk scores.

RESULTS

The three models predicted T2D risk with an average integrated area under the ROC curve equal to 0.83, 0.87 and 0.90, respectively, compared with 0.80 and 0.75 obtained using the FINDRISC and Framingham risk scores. The results were validated on two independent cohorts. Glucose values and particularly 2-h glucose during OGTT (2h-PG) had highest predictive value. Smoking, marital and professional status, waist circumference, blood pressure, age and gender were also predictive.

CONCLUSIONS

Our models provide an estimation of patient's risk over time and outweigh FINDRISC and Framingham traditional scores for prediction of T2D risk. Of note, the models developed in Scenarios 1 and 2, only exploited variables easily available at general patient visits.

Intravenous immunoglobulin in drug and device refractory patients with the symptoms of gastroparesis-an open-label study

BACKGROUND

Gastroparesis is a complex clinical entity; many aspects of which remain unknown. Although most patients have idiopathic, diabetic, or postsurgical gastroparesis, many are thought to have measurable neuromuscular abnormalities. Immunotherapy has recently been utilized to treat suspected autoimmune gastrointestinal dysmotility.

METHODS

Fourteen patients with symptoms of gastroparesis (Gp) who were refractory to drug/device were selected from 443 Gp patients from 2013 to 2015 who were treated at the University of Louisville motility center. All patients underwent a structural and psychiatric evaluation along with detailed psychological and behavioral examination to rule out eating disorders. We performed detailed neuromuscular evaluation and all 14 patients received at least 12 weeks of intravenous immunoglobulin (400 mg/kg infusion weekly). Response was defined subjectively (symptomatic improvement) using standardized IDIOM score system.

KEY RESULTS

All 14 patients had serological evidence and/or tissue evidence of immunological abnormality. Post-IVIG therapy, there was a significant improvement in symptoms scores for nausea, vomiting, early satiety, and abdominal pain.

CONCLUSIONS AND INFERENCES

Although limited by the absence of placebo group, the data illustrate the role of autoimmunity and neuromuscular evaluation in patients with gastroparesis and support the utility of a diagnostic trial of immunotherapy in an effort to improve therapeutic outcomes for such patients.

Family history of type 1 and type 2 diabetes and risk of latent autoimmune diabetes in adults (LADA)

BACKGROUND

A family history of diabetes (FHD) is a strong predictor of diabetes risk, yet has rarely been investigated in latent autoimmune diabetes in adults (LADA). This study therefore investigated the risk of LADA and type 2 diabetes (T2D) in relation to FHD, taking into account the type of diabetes in relatives.

METHODS

Data from a population-based study were used, including incident cases of LADA [glutamic acid decarboxylase antibody (GADA)-positive, n=378] and T2D (GADA-negative, n=1199), and their matched controls (n=1484). First-degree relatives with disease onset at age<40 years and taking insulin treatment were classified as type 1 diabetes (T1D) or, if otherwise, as T2D. Odds ratios (ORs) were adjusted for age, gender, BMI, education and smoking. Cases were genotyped for high- and low-risk HLA genotypes.

RESULTS

Both FHD-T1D (OR: 5.8; 95% CI: 3.2-10.3) and FHD-T2D (OR: 1.9; 95% CI: 1.5-2.5) were associated with an increased risk of LADA, whereas the risk of T2D was associated with FHD-T2D (OR: 2.7; 95% CI: 2.2-3.3), but not FHD-T1D. In LADA patients, FHD-T1D vs FHD-T2D was associated with higher GADA but lower C-peptide levels, lower prevalence of low-risk HLA genotypes (5.0% vs 28.6%, respectively; P=0.038) and a tendency for higher prevalence of high-risk genotypes (90.0% vs 69.1%, respectively; P=0.0576).

CONCLUSION

The risk of LADA is substantially increased with FHD-T1D but also, albeit significantly less so, with FHD-T2D. This supports the idea of LADA as a mix of both T1D and T2D, but suggests that the genes related to T1D have greater impact. LADA patients with FHD-T1D had more T1D-like features, emphasizing the heterogeneity of LADA.

The Level of Autoantibodies Targeting Eukaryote Translation Elongation Factor 1 α1 and Ubiquitin-Conjugating Enzyme 2L3 in Nondiabetic Young Adults

BACKGROUND

The prevalence of novel type 1 diabetes mellitus (T1DM) antibodies targeting eukaryote translation elongation factor 1 alpha 1 autoantibody (EEF1A1-AAb) and ubiquitin-conjugating enzyme 2L3 autoantibody (UBE2L3-AAb) has been shown to be negatively correlated with age in T1DM subjects. Therefore, we aimed to investigate whether age affects the levels of these two antibodies in nondiabetic subjects.

METHODS

EEF1A1-AAb and UBE2L3-AAb levels in nondiabetic control subjects (n=150) and T1DM subjects (n=101) in various ranges of age (18 to 69 years) were measured using an enzyme-linked immunosorbent assay. The cutoff point for the presence of each autoantibody was determined based on control subjects using the formula: [mean absorbance+3×standard deviation].

RESULTS

In nondiabetic subjects, there were no significant correlations between age and EEF1A1-AAb and UBE2L3-AAb levels. However, there was wide variation in EEF1A1-AAb and UBE2L3-AAb levels among control subjects <40 years old; the prevalence of both EEF1A1-AAb and UBE2L3-AAb in these subjects was 4.4%. When using cutoff points determined from the control subjects <40 years old, the prevalence of both autoantibodies in T1DM subjects was decreased (EEFA1-AAb, 15.8% to 8.9%; UBE2L3-AAb, 10.9% to 7.9%) when compared to the prevalence using the cutoff derived from the totals for control subjects.

CONCLUSION

There was no association between age and EEF1A1-AAb or UBE2L3-AAb levels in nondiabetic subjects. However, the wide variation in EEF1A1-AAb and UBE2L3-AAb levels apparent among the control subjects <40 years old should be taken into consideration when determining the cutoff reference range for the diagnosis of T1DM.

Glutamic acid decarboxylase autoantibodies are dominant but insufficient to identify most Chinese with adult-onset non-insulin requiring autoimmune diabetes: LADA China study 5

AIMS

Adult-onset autoimmune diabetes is prevalent in China, in contrast to childhood-onset type 1 diabetes mellitus. Islet autoantibodies are the most important immune biomarkers to diagnose autoimmune diabetes. We assayed four different islet autoantibodies in recently diagnosed adult non-insulin-requiring diabetes Chinese subjects to investigate the best antibody assay strategy for the correct diagnosis of these subjects.

METHODS

LADA China study is a nation-wide multicenter study conducted in diabetes patients from 46 university-affiliated hospitals in China. Non-insulin-treated newly diagnosed adult diabetes patients (n = 2388) were centrally assayed for glutamic acid decarboxylase autoantibody (GADA), protein tyrosine phosphatase-2 autoantibody (IA-2A), and zinc transporter 8 autoantibody (ZnT8A) by radioligand assay and insulin autoantibody (IAA) by microtiter plate radioimmunoassay. Clinical data were determined locally.

RESULTS

Two hundred and six (8.63 %) subjects were autoantibody positive, of which GADA identified 5.78 % (138/2388) of the total, but only 67 % (138/206) of the autoimmune cases. IA-2A, ZnT8A, and IAA were found in 1.51, 1.84, and 1.26 % of the total study subjects, respectively. When assaying three islet autoantibodies, the most effective strategy was the combination of GADA, ZnT8A, and IAA, which could identify 92.2 % (190/206) autoimmune diabetes patients. The clinical data showed that those subjects with positive GADA had lower random C-peptide than autoantibody negative subjects (P < 0.05).

CONCLUSIONS

As with Europeans, GADA is the dominant autoantibody in this form of autoimmune diabetes in China, but in contrast to Europeans, screening should include other diabetes-associated autoantibodies.

GAD Antibodies as Key Link Between Chronic Intestinal Pseudoobstruction, Autonomic Neuropathy, and Limb Stiffness in a Nondiabetic Patient: A CARE-Compliant Case Report and Review of the Literature

Chronic intestinal pseudoobstruction (CIP) can be a severe burden and even a life-threatening disorder. Typically, several years of uncertainty are passing before diagnosis. We are reporting the case of a young woman with a decade of severe, progressive gastrointestinal dysmotility. Unusually, she had also developed an autonomic neuropathy, and a stiff limb syndrome.In addition to achalasia and CIP the young woman also developed neuropathic symptoms: orthostatic intolerance, urinary retention, a Horner syndrome, and lower limb stiffness. Careful interdisciplinary diagnostics excluded underlying infectious, rheumatoid, metabolic or tumorous diseases.The detection of GAD (glutamic acid decarboxylase) antibodies, however, seemed to link CIP, autonomic neuropathy, and limb stiffness and pointed at an autoimmune origin of our patient's complaints. This was supported by the positive effects of intravenous immunoglobulin. In response to this therapy the body weight had stabilized, orthostatic tolerance had improved, and limb stiffness was reversed.The case suggested that GAD antibodies should be considered in CIP also in nondiabetic patients. This may support earlier diagnosis and immunotherapy.

Latent autoimmune diabetes of the adult: current knowledge and uncertainty

Patients with adult-onset autoimmune diabetes have less Human Leucocyte Antigen (HLA)-associated genetic risk and fewer diabetes-associated autoantibodies compared with patients with childhood-onset Type 1 diabetes. Metabolic changes at diagnosis reflect a broad clinical phenotype ranging from diabetic ketoacidosis to mild non-insulin-requiring diabetes, also known as latent autoimmune diabetes of the adult (LADA). This latter phenotype is the most prevalent form of adult-onset autoimmune diabetes and probably the most prevalent form of autoimmune diabetes in general. Although LADA is associated with the same genetic and immunological features as childhood-onset Type 1 diabetes, it also shares some genetic features with Type 2 diabetes, which raises the question of genetic heterogeneity predisposing to this form of the disease. The potential value of screening patients with adult-onset diabetes for diabetes-associated autoantibodies to identify those with LADA is emphasized by their lack of clinically distinct features, their different natural history compared with Type 2 diabetes and their potential need for a dedicated management strategy. The fact that, in some studies, patients with LADA show worse glucose control than patients with Type 2 diabetes, highlights the need for further therapeutic studies. Challenges regarding classification, epidemiology, genetics, metabolism, immunology, clinical presentation and treatment of LADA were discussed at a 2014 workshop arranged by the Danish Diabetes Academy. The presentations and discussions are summarized in this review, which sets out the current ideas and controversies surrounding this form of diabetes.

Presence of anti-GAD in a non-diabetic population of adults; time dynamics and clinical influence: results from the HUNT study

BACKGROUND

It is well known that anti-GAD (glutamic acid decarboxylase) serves as a marker for development of autoimmune diabetes in adults. On the other hand, the clinical implications of anti-GAD positivity in persistently non-diabetic (PND) adults are poorly elucidated. Our aim was to establish the frequency of anti-GAD in PNDs in an all-population-based cohort from the Nord-Trøndelag health study (HUNT) and to prospectively test for associations with glucose tolerance and thyroid autoimmunity.

METHODS

We formed a primary study population (4496 individuals), selected randomly from the age group 20-90 years (50% men/women), who were non-diabetic both at HUNT2 (1995-1997) and HUNT3 (2006-2008). Anti-GAD-positive individuals at HUNT2, together with anti-GAD-negative individuals aged 20-29 years, were retested for anti-GAD positivity at HUNT3. A secondary study population consisted of individuals with type 2 diabetes (T2D, n=349) at HUNT3 who developed diabetes between HUNT2 and HUNT3.

RESULTS

The frequency of anti-GAD positivity in PND was 1.7% (n=76) at HUNT2. Positivity did not associate with gender, family history of diabetes, or glucose levels, but was associated with thyroid-associated autoimmunity (increased frequency of positivity for anti-TPO (thyroid peroxidase), p<0.002). HLA-DQA1/DQB1, a risk haplotype for autoimmunity, was also associated with anti-GAD positivity in PND. The incidence of anti-GAD positivity was low (0.4%) in the subsample of individuals who were anti-GAD negative in HUNT2. Anti-GAD positivity in PNDs was frequently evanescent, with 54% losing, usually low-grade, positivity between HUNT2 and HUNT3. An evanescent state of autoimmunity as assessed by anti-GAD positivity during "pre-diabetes" in individuals later diagnosed with T2D could, however, not be affirmed.

CONCLUSIONS

Anti-GAD positivity in PND is associated with HLA risk haplotypes and thyroid autoimmunity but not with clinical parameters of diabetes. Fleeting anti-GAD positivity is common; however, results do not support the notion of a history of autoimmunity in T2D in the present cohort.

Diabetes autoantibodies do not predict progression to diabetes in adults: the Diabetes Prevention Program

AIMS

To determine if the presence of diabetes autoantibodies predicts the development of diabetes among participants in the Diabetes Prevention Program.

METHODS

A total of 3050 participants were randomized into three treatment groups: intensive lifestyle intervention, metformin and placebo. Glutamic acid decarboxylase (GAD) 65 autoantibodies and insulinoma-associated-2 autoantibodies were measured at baseline and participants were followed for 3.2 years for the development of diabetes.

RESULTS

The overall prevalence of GAD autoantibodies was 4.0%, and it varied across racial/ethnic groups from 2.4% among Asian-Pacific Islanders to 7.0% among non-Hispanic black people. There were no significant differences in BMI or metabolic variables (glucose, insulin, HbA(1c), estimated insulin resistance, corrected insulin response) stratified by baseline GAD antibody status. GAD autoantibody positivity did not predict diabetes overall (adjusted hazard ratio 0.98; 95% CI 0.56-1.73) or in any of the three treatment groups. Insulinoma-associated-2 autoantibodies were positive in only one participant (0.033%).

CONCLUSIONS

These data suggest that 'diabetes autoimmunity', as reflected by GAD antibodies and insulinoma-associated-2 autoantibodies, in middle-aged individuals at risk for diabetes is not a clinically relevant risk factor for progression to diabetes.

The many faces of diabetes: a disease with increasing heterogeneity

Diabetes is a much more heterogeneous disease than the present subdivision into types 1 and 2 assumes; type 1 and type 2 diabetes probably represent extremes on a range of diabetic disorders. Both type 1 and type 2 diabetes seem to result from a collision between genes and environment. Although genetic predisposition establishes susceptibility, rapid changes in the environment (ie, lifestyle factors) are the most probable explanation for the increase in incidence of both forms of diabetes. Many patients have genetic predispositions to both forms of diabetes, resulting in hybrid forms of diabetes (eg, latent autoimmune diabetes in adults). Obesity is a strong modifier of diabetes risk, and can account for not only a large proportion of the epidemic of type 2 diabetes in Asia but also the ever-increasing number of adolescents with type 2 diabetes. With improved characterisation of patients with diabetes, the range of diabetic subgroups will become even more diverse in the future.

Anti-diabetic effects of CTB-APSL fusion protein in type 2 diabetic mice

To determine whether cholera toxin B subunit and active peptide from shark liver (CTB-APSL) fusion protein plays a role in treatment of type 2 diabetic mice, the CTB-APSL gene was cloned and expressed in silkworm (Bombyx mori) baculovirus expression vector system (BEVS), then the fusion protein was orally administrated at a dose of 100 mg/kg for five weeks in diabetic mice. The results demonstrated that the oral administration of CTB-APSL fusion protein can effectively reduce the levels of both fasting blood glucose (FBG) and glycosylated hemoglobin (GHb), promote insulin secretion and improve insulin resistance, significantly improve lipid metabolism, reduce triglycerides (TG), total cholesterol (TC) and low density lipoprotein (LDL) levels and increase high density lipoprotein (HDL) levels, as well as effectively improve the inflammatory response of type 2 diabetic mice through the reduction of the levels of inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Histopathology shows that the fusion protein can significantly repair damaged pancreatic tissue in type 2 diabetic mice, significantly improve hepatic steatosis and hepatic cell cloudy swelling, reduce the content of lipid droplets in type 2 diabetic mice, effectively inhibit renal interstitial inflammatory cells invasion and improve renal tubular epithelial cell nucleus pyknosis, thus providing an experimental basis for the development of a new type of oral therapy for type 2 diabetes.

Family history of Type 1 diabetes affects insulin secretion in patients with 'Type 2' diabetes

AIMS

The aim was to evaluate the impact of family history of diabetes on the phenotype of patients diagnosed with Type 2 diabetes and the frequency of susceptibility genotypes.

METHODS

Patients with Type 2 diabetes with family history for both Type 1 and Type 2 diabetes (FH(MIX, n) = 196) or Type 2 diabetes only (FH(T2), n = 139) matched for age, sex, BMI and age at diagnosis, underwent an oral glucose tolerance test and a combined glucagon test and insulin tolerance test. Glutamic acid decarboxylase (GAD) antibodies and major Type 1 and Type 2 diabetes susceptibility gene variants were analysed. Patients were stratified into groups according to family history or GAD antibody positivity (GADA+, GADA-) or a combination of these (GADA+/FH(MIX), GADA+/FH(T2), GADA-/FH(MIX), GADA-/FH(T2)).

RESULTS

Compared with other patients, those with FH(MIX) more often had GAD antibodies (14.3 vs. 4.3%, P = 0.003), and those with both FH(MIX) and GAD antibodies had the highest frequency of insulin deficiency (stimulated serum C-peptide < 0.7 nmol/l, GADA+/FH(MIX) 46.4% vs. GADA-/FH(MIX) 9.5% (P < 0.00001), GADA-/FH(T2) 4.5% (P < 0.00001), GADA+/FH(T2) 0%). Patients with GADA+/FH(MIX) more often had HLA-DQB1 risk genotypes compared with patients with GADA-/FH(MIX) or GADA-/FH(T2D) (47 vs. 23 or 14%, P = 0.05 and P < 0.00001, respectively). In logistic regression analyses, FH(MIX), GAD antibody positivity and HLA risk genotypes were independently associated with insulin deficiency.

CONCLUSION

A family history for both type 1 and type 2 diabetes was associated with higher prevalence of GAD antibodies and HLA-DQB1 risk genotypes than a family history of type 2 diabetes only, and was associated with earlier and more severe development of insulin deficiency, which was only partially explained by GAD antibodies and HLA.

Worse glycaemic control in LADA patients than in those with type 2 diabetes, despite a longer time on insulin therapy

AIMS/HYPOTHESIS

Our aim was to study whether glycaemic control differs between individuals with latent autoimmune diabetes in adults (LADA) and patients with type 2 diabetes, and whether it is influenced by time on insulin therapy.

METHODS

We performed a retrospective study of 372 patients with LADA (205 men and 167 women; median age 54 years, range 35-80 years) from Swedish cohorts from Skåne (n = 272) and Västerbotten (n = 100). Age- and sex-matched patients with type 2 diabetes were included as controls. Data on the use of oral hypoglycaemic agents (OHAs), insulin and insulin-OHA combination therapy was retrieved from the medical records. Poor glycaemic control was defined as HbA(1c) ≥7.0% (≥53 mmol/mol) at follow-up.

RESULTS

The individuals with LADA and with type 2 diabetes were followed for an average of 107 months. LADA patients were leaner than type 2 diabetes patients at diagnosis (BMI 27.7 vs 31.0 kg/m(2); p < 0.001) and follow-up (BMI 27.9 vs 30.2 kg/m(2); p < 0.001). Patients with LADA had been treated with insulin for longer than those with type 2 diabetes (53.3 vs 28.8 months; p < 0.001). There was no significant difference between the patient groups with regard to poor glycaemic control at diagnosis, but more patients with LADA (67.8%) than type 2 diabetes patients (53.0%; p < 0.001) had poor glycaemic control at follow-up. Patients with LADA had worse glycaemic control at follow-up compared with participants with type 2 diabetes (OR = 1.8, 95% CI 1.2, 2.7), adjusted for age at diagnosis, HbA(1c), BMI at diagnosis, follow-up time and duration of insulin treatment.

CONCLUSIONS/INTERPRETATION

Individuals with LADA have worse glycaemic control than patients with type 2 diabetes despite a longer time on insulin therapy.

Association of variants in HLA-DQA1-DQB1, PTPN22, INS, and CTLA4 with GAD autoantibodies and insulin secretion in nondiabetic adults of the Botnia Prospective Study

OBJECTIVE

Previously, we observed an association between family history of type 1 diabetes and development of non-insulin-dependent diabetes. The aims of this study were to assess whether type 1 diabetes susceptibility gene variants explain this association and investigate the effect of the variants on insulin secretion and presence of glutamic acid decarboxylase autoantibodies (GADA) in nondiabetic adults.

DESIGN AND METHODS

Polymorphisms in INS (rs689), PTPN22 (rs2476601), CTLA4 (rs3087243), and the HLA-DQA1-DQB1 regions (rs2187668 and rs7454108 tagging HLA-DQ2.5 and HLA-DQ8 respectively) were genotyped in the Botnia Prospective Study (n=2764), in which initially nondiabetic participants were followed for a mean of 8.1 years.

RESULTS

The variants did not explain the association between family history of type 1 diabetes and development of non-insulin-dependent diabetes. In these nondiabetic adults, HLA-DQ AND PTPN22 risk genotypes were associated with GADA (HLA-DQ2.5/HLA-DQ8 or HLA-DQ8: OR (95% CI): 1.7 (1.3-2.3), P=0.0004; PTPN22 CT/TT: OR: 1.6 (1.2-2.2), P=0.003; P values were adjusted for sex, age, BMI, and follow-up time). A higher genetic risk score was associated with lower insulin secretion (insulinogenic index: 13.27 (16.27) vs 12.69 (15.27) vs 10.98 (13.06), P=0.02) and better insulin sensitivity index (risk score of 0-1 vs 2-3 vs 4-6: 142 (111) vs 144 (118) vs 157 (127), P=0.01) at baseline and a poorer capacity to compensate for the increased insulin demand after follow-up.

CONCLUSIONS

In nondiabetic adults, HLA-DQ2.5/HLA-DQ8 and PTPN22 CT/TT genotypes were associated with GADA.

Time dynamics of autoantibodies are coupled to phenotypes and add to the heterogeneity of autoimmune diabetes in adults: the HUNT study, Norway

AIMS

The aetiology of latent autoimmune diabetes in adults (LADA), assessed by autoimmune markers, is insufficiently clarified. We cross-sectionally investigated the prevalence and prospectively the prediabetic and postdiabetic presence of antibodies to glutamic acid decarboxylase (GADA), insulinoma-associated protein 2 and zinc transporter 8 in LADA and in type 1 diabetes.

METHODS

We included 208 'classic' type 1, 161 LADA and 302 type 2 diabetic cases from the second (HUNT2: 1995–1997) and third (HUNT3: 2006–2008) Nord-Trøndelag health surveys. Prospective data were available for 59 type 1, 44 LADA and 302 type 2 diabetic cases followed from HUNT2 to HUNT3. From HUNT3, 24 type 1 diabetic and 31 LADA incident cases were available.

RESULTS

Cross-sectionally, 90% of LADA cases were positive for only one antibody (10% multiple-antibodypositive). Prospectively, 59% of GADA-positive LADA patients in HUNT2 were no longer positive in HUNT3. LADA patients who became negative possessed less frequently risk HLA haplotypes and were phenotypically more akin to those with type 2 diabetes than to those who stayed positive. Still, those losing positivity differed from those with type 2 diabetes by lower C-peptide levels (p = 0.009). Of incident LADA cases in HUNT3, 64% were already antibody-positive in HUNT2, i.e. before diabetes diagnosis. These incident LADA cases were phenotypically more akin to type 1 diabetes than were those who did not display positivity in HUNT2.

CONCLUSION/INTERPRETATION

The pattern of antibodies, the postdiabetic loss or persistence as well as the prediabetic absence or presence of antibodies influence LADA phenotypes. Time-dependent presence or absence of antibodies adds new modalities to the heterogeneity of LADA.

Pyridoxal 5'-phosphate (PLP) deficiency might contribute to the onset of type I diabetes

The incidence of type I diabetes is rising worldwide, particularly in young children. Type I diabetes is considered a multifactorial disease with genetic predisposition and environmental factors participating. Currently, despite years of research, there is no consensus regarding the factors that initiate the autoimmune response. Type I diabetes is preceded by autoimmunity to islet antigens, among them the protein glutamic acid decarboxylase, GAD-65. Pyridoxal 5'-phosphate (PLP) is formed from vitamin B6 by the action of pyridoxal kinase. Interaction of GAD65 with PLP is necessary for GAD65-mediated synthesis of the neurotransmitter γ-aminobutyric acid (GABA). PLP is also a required cofactor for dopamine synthesis by L-aromatic decarboxylase (L-AADC). Both GAD65 and L-AADC are expressed in pancreatic islets. Here it is proposed that lack of the vitamin B6 derivative pyridoxal 5'-phosphate might contribute to the appearance of pancreatic islet autoimmunity and type I diabetes onset.

Bacterial endotoxin activity in human serum is associated with dyslipidemia, insulin resistance, obesity, and chronic inflammation

OBJECTIVE

To investigate whether bacterial lipopolysaccharide (LPS) activity in human serum is associated with the components of the metabolic syndrome (MetS) in type 1 diabetic patients with various degrees of kidney disease and patients with IgA glomerulonephritis (IgAGN).

RESEARCH DESIGN AND METHODS

Serum LPS activity was determined with the Limulus Amoebocyte Lysate chromogenic end point assay in type 1 diabetic patients with a normal albumin excretion rate (n = 587), microalbuminuria (n = 144), macroalbuminuria (n = 173); patients with IgAGN (n = 98); and in nondiabetic control subjects (n = 345). The relationships of the LPS/HDL ratio and MetS-associated variables were evaluated with Pearson correlation.

RESULTS

The MetS was more prevalent in type 1 diabetic patients (48%) than in patients with IgAGN (15%). Diabetic patients with macroalbuminuria had a significantly higher serum LPS/HDL ratio than patients with IgAGN. In the normoalbuminuric type 1 diabetic group, patients in the highest LPS/HDL quartile were diagnosed as having the MetS three times more frequently than patients in the lowest quartile (69 vs. 22%; P < 0.001). High LPS activity was associated with higher serum triglyceride concentration, earlier onset of diabetes, increased diastolic blood pressure, and elevated urinary excretion of monocyte chemoattractant protein-1.

CONCLUSIONS

High serum LPS activity is strongly associated with the components of the MetS. Diabetic patients with kidney disease seem to be more susceptible to metabolic endotoxemia than patients with IgAGN. Bacterial endotoxins may thus play an important role in the development of the metabolic and vascular abnormalities commonly seen in obesity and diabetes-related diseases.

State of the union between metabolism and the immune system in type 2 diabetes

Lymphocytes and myeloid cells (monocyte/macrophages) have important roles in multiple types of diseases characterized by unresolved inflammation. The relatively recent appreciation of obesity, insulin resistance and type 2 diabetes (T2D) as chronic inflammatory diseases has stimulated interest in understanding the role of immune cells in metabolic imbalance. Myeloid cells regulate inflammation through cytokine production and the adipose tissue remodeling that accompanies hyper-nutrition, thus are critical players in metabolic homeostasis. More recently, multiple studies have indicated a role for T cells in obesity-associated inflammation and insulin resistance in model organisms, with parallel work indicating that pro-inflammatory changes in T cells also associate with human T2D. Furthermore, the expansion of T cells with similar antigen-binding sites in obesity and T2D indicates these diseases share characteristics previously attributed to inflammatory autoimmune disorders. Parallel pro-inflammatory changes in the B-cell compartment of T2D patients have also been identified. Taken together, these studies indicate that in addition to accepted pro-inflammatory roles of myeloid cells in T2D, pro-inflammatory skewing of both major lymphocyte subsets has an important role in T2D disease pathogenesis. Basic immunological principles suggest that alterations in lymphocyte function in obesity and T2D patients are an integral part of a feed-forward pro-inflammatory loop involving additional cell types. Importantly, the pro-inflammatory loop almost inevitably includes adipocytes, known to respond to pro-inflammatory, pro-diabetogenic cytokines originating from the myeloid and lymphoid compartments. We propose a model for inflammation in T2D that functionally links lymphocyte, myeloid and adipocyte contributions, and importantly proposes that tools for B-cell ablation or regulation of T-cell subset balance may have a place in the endocrinologist's limited arsenal.

Latent autoimmune diabetes in adults differs genetically from classical type 1 diabetes diagnosed after the age of 35 years

OBJECTIVE

We studied differences between patients with latent autoimmune diabetes in adults (LADA), type 2 diabetes, and classical type 1 diabetes diagnosed after age 35 years.

RESEARCH DESIGN AND METHODS

Polymorphisms in HLA-DQB1, INS, PTPN22, and CTLA4 were genotyped in patients with LADA (n = 213), type 1 diabetes diagnosed at >35 years of age (T1D(>35y); n = 257) or <20 years of age (T1D(<20y); n = 158), and type 2 diabetes.

RESULTS

Although patients with LADA had an increased frequency of HLA-DQB1 and PTPN22 risk genotypes and alleles compared with type 2 diabetic subjects, the frequency was significantly lower compared with T1D(>35y) patients. Genotype frequencies, measures of insulin secretion, and metabolic traits within LADA differed according to GAD antibody (GADA) quartiles, but even the highest quartile differed from type 1 diabetes. Having two or more risk genotypes was associated with lower C-peptide concentrations in LADA.

CONCLUSIONS

LADA patients differed genetically and phenotypically from both T1D(>35y) and type 2 diabetic patients in a manner dependent on GADA levels.