The prevalence of the 65-kilodalton isoform of glutamic acid decarboxylase autoantibodies by glucose tolerance status in elderly patients from the cardiovascular health study

Metabolic Clusters and Outcomes in Older Adults: The Cardiovascular Health Study

BACKGROUND/OBJECTIVES

Few studies have the requisite phenotypic information to define metabolic patterns that may inform our understanding of the pathophysiology and consequences of diabetes in older adults. We sought to characterize clusters of older adults on the basis of shared metabolic features.

DESIGN

Population-based prospective cohort study.

SETTING

Four U.S. Cardiovascular Health Study field centers.

PARTICIPANTS

Individuals aged 65 and older taking no glucose-lowering agents (N = 2,231).

MEASUREMENTS

K-means cluster analysis of 11 metabolic parameters (fasting and postload serum glucose and plasma insulin, fasting C-peptide, body mass index, C-reactive protein (CRP), estimated glomerular filtration rate (eGFR), albuminuria, carboxymethyl lysine (an advanced glycation end-product), procollagen III N-terminal propeptide (a fibrotic marker)) and their associations with incident cardiovascular disease, diabetes, disability, and mortality over 8 to 14.5 years of follow-up and with measures of subclinical cardiovascular disease.

RESULTS

A 6-cluster solution provided robust differentiation into distinct, identifiable clusters. Cluster A (n = 739) had the lowest glucose and insulin and highest eGFR and the lowest rates of all outcomes. Cluster B (n = 419) had high glucose and insulin and intermediate rates of most outcomes. Cluster C (n = 118) had the highest insulin. Cluster D (n = 129) had the highest glucose with much lower insulin. Cluster E (n = 314) had the lowest eGFR and highest albuminuria. Cluster F (n = 512) had the highest CRP. Rates of CVD, mortality, and subclinical atherosclerosis were highest in clusters C, D, and E and were similar to rates in participants with treated diabetes. Incidence of disability was highest in Cluster C.

CONCLUSION

Clustering according to metabolic parameters identifies distinct phenotypes that are strongly associated with clinical and functional outcomes, even at advanced age.

Immunological and clinical characteristics of latent autoimmune diabetes in the elderly

BACKGROUND

Latent autoimmune diabetes in adults (LADA) is determined by both a noninsulin-dependent clinical presentation and an autoimmune pathogenic process. Glutamic acid decarboxylase antibody (GADA) constitutes the most important marker, although IA-2A and ZnT8A also define LADA presentation. Type 2 diabetes mellitus (T2DM) is the most prevalent type particularly over 65 years old. Studies about autoimmunity in this age group are scarce.

OBJECTIVE

The aim of this work was to determine whether three autoantibodies for diabetes autoimmunity were present in elderly T2DM patients, and to assess the distinctive clinical features of autoantibody-positive patients.

RESEARCH DESIGN AND METHODS

We recruited 153 patients with diabetes with onset of diabetes after 65 years of age and a BMI under 30 kg/m² .

RESULTS

The prevalence of at least one of the autoantibodies was 15.68% (24/153). The most prevalent autoantibody was GADA with 8.49% (13/153), followed by ZnT8A with 6.50% (10/153) and IA2A with 1.96% (3/153). The autoimmunity-positive group presented higher HbA1c (7.01 ± 1.98 vs 6.35 ± 1.01; P = 0.007) and more prevalent insulin therapy (25% vs 10.85%; P = 0.047). GADA-positive patients with diabetes presented higher FPG (7.79 ± 3.79 mmol/L vs 6.43 ± 1.6 mmol/L; P = 0.014) and insulin therapy more frequently (46% vs 10.71%; p = 0.015). GADA titre levels in the individuals with BMI under 27 kg/m² were higher (35.00 ± 4.20) than those in the group with BMI over 27 kg/m² (8.83 ± 3.041; P = 0.0005).

CONCLUSION

Autoantibodies GADA and Znt8A may be useful markers in identifying a subgroup of older patients with a clinical presentation of diabetes which could be characterized as latent autoimmune diabetes in the elderly.

Islet Autoantibody Patterns in Patients With Type 2 Diabetes Aged 60 and Higher: A Cross-Sectional Study in a Chinese Hospital

BACKGROUND

Some elderly citizens with a clinical diagnosis of type 2 diabetes had evidence of positive islet autoantibodies. We aimed to discover their islet autoantibody patterns and independent correlative factors that might lead to a better understanding of significance of islet autoimmunity in the progression of elderly diabetes.

METHODS

A total of 541 inpatients of clinically diagnosed type 2 diabetes aged 60 and over were recruited. Three islet autoantibodies including insulin autoantibody (IAA), islet cell antibody (ICA), and glutamic acid decarboxylase antibody (GADA) as well as clinical and biochemical characteristics were tested and collected in Huashan Hospital. Associations between these antibodies and clinical features were analyzed by Spearman correlation and binary logistic analyses.

RESULTS

In our current study, total positive rate of islet autoantibodies (IAA, ICA, and GADA) was 35.67% with 26.62% for individual IAA, 5.55% for ICA, and 5.91% for GADA, in elderly with type 2 diabetes. None of combinations of such autoantibodies were observed, with the exception of IAA + ICA (0.74%, n = 4), IAA + GADA (1.48%, n = 8), and ICA + GADA (0.18%, n = 1). Compared with GADA negative group, patients in positive group tended to have lower level of fasting and postprandial C peptide, fasting blood glucose (FBG), and body mass index (BMI). After adjusted for the BMI, FBG, and postprandial C peptide, fasting C peptide seemed to be an independent factor related to GADA positivity (OR = 0.52, p = 0.02). As for patients with positive IAA, they were more likely to have insulin treatment with longer duration of diabetes, higher level of BMI, and lower level of postprandial C peptide. After adjusted for the duration of diabetes, BMI, and postprandial C peptide, insulin treatment was a significant predictor for IAA positivity (OR = 5.20, p < 0.0001). Furthermore, hs-CRP was positively related to ICA positivity, and hs-CRP appeared to be an independent indicator for ICA (OR = 3.43, p = 0.008).

CONCLUSION

In elderly with type 2 diabetes, high prevalence rate of IAA was frequently accompanied with insulin treatment, while ICA and GADA were more closely associated with the systemic inflammation and beta-cell failure, respectively.

Identification of Unique Antigenic Determinants in the Amino Terminus of IA-2 (ICA512) in Childhood and Adult Autoimmune Diabetes: New Biomarker Development

OBJECTIVE

The characterization of diverse subtypes of diabetes is a dynamic field of clinical research and an active area of discussion. The objective of this study was to identify new antigenic determinants in the neuroendocrine autoantigen IA-2 (ICA512) and assess whether circulating autoantibodies directed to new IA-2 epitopes identify autoimmune diabetes in young and adult populations with diabetes.

RESEARCH DESIGN AND METHODS

Clinically diagnosed patients with type 2 diabetes (n = 258; diabetes duration: 0.01-31 years) were evaluated using a new biomarker detecting autoantibodies directed to the extracellular domain of the neuroendocrine autoantigen IA-2 (IA-2ec). The proportion of IA-2ec autoantibodies was also evaluated in newly diagnosed patients with type 1 diabetes (n = 150; diabetes duration: 0.04-0.49 years). In addition, IA-2 (intracellular domain), GAD65, and zinc transporter 8 autoantibodies were assayed.

RESULTS

IA-2ec autoantibodies were detected in patients with type 1 diabetes and, surprisingly, in 5% of patients with type 2 diabetes without serologic responses to other IA-2 antigenic epitopes or other islet autoantigens. We also assessed the ability of IA-2ec-derived peptides to elicit CD4⁺ T-cell responses by stimulating peripheral blood mononuclear cells from patients with type 1 diabetes (n = 18) and HLA-matched healthy subjects (n = 13) with peptides and staining with the peptide/DQ8-specific tetramers, observing disease-associated responses to previously unreported epitopes within IA-2ec.

CONCLUSIONS

We developed a new antibody biomarker identifying novel antigenic determinants within the N terminus of IA-2. IA-2ec autoantibodies can be detected in patients with type 1 diabetes and in a subgroup of adult autoimmune patients with type 2 diabetes phenotype negative for conventional islet autoantibody testing. These observations suggest that islet autoimmunity may be more common in clinically diagnosed type 2 diabetes than previously observed.

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.

Islet autoimmunity identifies a unique pattern of impaired pancreatic beta-cell function, markedly reduced pancreatic beta cell mass and insulin resistance in clinically diagnosed type 2 diabetes

There is a paucity of literature describing metabolic and histological data in adult-onset autoimmune diabetes. This subgroup of diabetes mellitus affects at least 5% of clinically diagnosed type 2 diabetic patients (T2DM) and it is termed Latent Autoimmune Diabetes in Adults (LADA). We evaluated indexes of insulin secretion, metabolic assessment, and pancreatic pathology in clinically diagnosed T2DM patients with and without the presence of humoral islet autoimmunity (Ab). A total of 18 patients with at least 5-year duration of clinically diagnosed T2DM were evaluated in this study. In those subjects we assessed acute insulin responses to arginine, a glucose clamp study, whole-body fat mass and fat-free mass. We have also analyzed the pancreatic pathology of 15 T2DM and 43 control cadaveric donors, using pancreatic tissue obtained from all the T2DM organ donors available from the nPOD network through December 31, 2013. The presence of islet Ab correlated with severely impaired β-cell function as demonstrated by remarkably low acute insulin response to arginine (AIR) when compared to that of the Ab negative group. Glucose clamp studies indicated that both Ab positive and Ab negative patients exhibited peripheral insulin resistance in a similar fashion. Pathology data from T2DM donors with Ab or the autoimmune diabetes associated DR3/DR4 allelic class II combination showed reduction in beta cell mass as well as presence of autoimmune-associated pattern A pathology in subjects with either islet autoantibodies or the DR3/DR4 genotype. In conclusion, we provide compelling evidence indicating that islet Ab positive long-term T2DM patients exhibit profound impairment of insulin secretion as well as reduced beta cell mass seemingly determined by an immune-mediated injury of pancreatic β-cells. Deciphering the mechanisms underlying beta cell destruction in this subset of diabetic patients may lead to the development of novel immunologic therapies aimed at halting the disease progression in its early stage.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of schizophrenia, part 2: update 2012 on the long-term treatment of schizophrenia and management of antipsychotic-induced side effects

Abstract These updated guidelines are based on a first edition of the World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of schizophrenia published in 2006. For this 2012 revision, all available publications pertaining to the biological treatment of schizophrenia were reviewed systematically to allow for an evidence-based update. These guidelines provide evidence-based practice recommendations that are clinically and scientifically meaningful. They are intended to be used by all physicians diagnosing and treating people suffering from schizophrenia. Based on the first version of these guidelines, a systematic review of the MEDLINE/PUBMED database and the Cochrane Library, in addition to data extraction from national treatment guidelines, has been performed for this update. The identified literature was evaluated with respect to the strength of evidence for its efficacy and then categorised into six levels of evidence (A-F) and five levels of recommendation (1-5) ( Bandelow et al. 2008a ,b, World J Biol Psychiatry 9:242, see Table 1 ). This second part of the updated guidelines covers long-term treatment as well as the management of relevant side effects. These guidelines are primarily concerned with the biological treatment (including antipsychotic medication and other pharmacological treatment options) of adults suffering from schizophrenia.

Humoral autoimmunity in type 1 diabetes: prediction, significance, and detection of distinct disease subtypes

Type 1 diabetes mellitus (T1D) is an autoimmune disease encompassing the T-cell-mediated destruction of pancreatic β cells and the production of autoantibodies against islet proteins. In humoral autoimmunity in T1D, the detection of islet autoantibodies and the examination of their associations with genetic factors and cellular autoimmunity constitute major areas in both basic research and clinical practice. Although insulin is a key autoantigen and may be primus inter pares in importance among T1D autoantigens, an abundant body of research has also revealed other autoantigens associated with the disease process. Solid evidence indicates that autoantibodies against islet targets serve as key markers to enroll newly diagnosed T1D patients and their family members in intervention trials aimed at preventing or halting the disease process. The next challenge is perfecting mechanistic bioassays to be used as end points for disease amelioration following immunomodulatory therapies aimed at blocking immune-mediated β-cell injury and, in turn, preserving β-cell function in type 1 diabetes mellitus.

GAD65 autoantibodies and its role as biomarker of Type 1 diabetes and Latent Autoimmune Diabetes in Adults (LADA)

One of the hallmarks of autoimmune diabetes is the presence of adaptive responses directed to neuroendocrine proteins. One of these proteins is glutamic acid decarboxylase (GAD). While GAD is widely distributed in neuroendocrine tissues, its specific significance in diabetes has paralleled the advances in understanding humoral and cellular immunity in Type 1 diabetes (T1D) and in a subset of Type 2 diabetes (T2D), going from the seminal discoveries of islet autoantibodies to the development and standardization of bioassays as diagnostic tools, to studies on the structure of GAD and its antigenic determinants. GAD65 autoantibodies can accurately predict T1D development in combination with other surrogate humoral biomarkers and they are considered the most sensitive and specific biomarker which identifies a subset of clinically diagnosed T2D termed Latent Autoimmune Diabetes in Adults (LADA). We and others provided evidence indicating that GAD65 autoantibody detection should be part of the diagnostic assessment for clinically diagnosed T2DM mainly because it predicts the rate of progression to insulin requirement in patients affected by LADA. More recently GAD has been used as a "tolerogenic vaccine" to preserve beta cell function in autoimmune diabetes. While the results of Phase III clinical trials did not substantiate the earlier promise of Phase I and II trials, there are still many unanswered questions and approaches that need to be investigated in the applications of GAD in the therapy of T1D and LADA.

The heterogeneity of diabetes: unraveling a dispute: is systemic inflammation related to islet autoimmunity?

Diabetes is an emblematic example of a heterogeneous disease. Systemic inflammation has emerged as a prominent factor in the type 2 diabetes pathoetiology, but it remains ill-defined in type 1 diabetes. There is a wide spectrum of associations between inflammatory responses and diabetic syndromes. At one end of this spectrum, there is type 1 diabetes for which there is convincing evidence that chronic inflammation of pancreatic islets is a central aspect of disease pathogenesis. At the opposite end, is type 2 diabetes that is clearly associated with systemic inflammation, which could be either the cause or simply mark the underlying pathology. Accumulating evidence has substantiated that a subgroup of adult patients clinically diagnosed with type 2 diabetes exhibit autoantibody responses to islet autoantigens. The presence of these immunologic abnormalities is associated with a severe insulin secretory defect and the absence of signs of systemic inflammation as documented by plasma C-reactive protein and fibrinogen levels that are comparable with those of control populations. Islet autoantibody evaluation should be part of the diagnostic assessment for clinically diagnosed type 2 diabetes not only because it might predict the rate of progression to insulin requirement in adult populations but also to identify a pathogenically distinct disease phenotype characterized by the absence of systemic inflammation and its related disorders. A more appropriate characterization of this subgroup of clinically diagnosed type 2 diabetes, diabetes of autoimmune pathogenesis, will promote future research into the etiology, natural history, and treatment.

Admissions for diabetic ketoacidosis in ethnic minority groups in a city hospital

Hospitalization for diabetic ketoacidosis (DKA) is increasing, perhaps due to the rising incidence of DKA in patients with type 2 diabetes mellitus (T2DM). Ethnic minority groups are at increased risk for T2DM. This study aimed at elucidating the characteristics of patients with ketosis-prone diabetes in a predominantly ethnic minority population. We performed a retrospective analysis of adults admitted with DKA at the Bronx Lebanon Hospital Center, Bronx, NY over 3 years. The patients were divided into cohorts based on type of diabetes and ethnicity. The cohorts were described and compared using statistical methods. We recorded 219 cases of DKA in 168 patients, 97% of whom were African American or Hispanic. Fifty-three (32%) patients had T2DM. New-onset diabetes, which was more common in T2DM (P < .0001), and African Americans (P = .008), occurred in 42 patients (25%). Readmission with DKA was more common in the Hispanic patients with type 1 diabetes mellitus (T1DM) (P = .0001). Type 2 diabetes mellitus was more prevalent in the African Americans (P = .04). Patients with T1DM had more severe acidosis than patients with T2DM (lower pH and bicarbonate and larger anion gap; P = .03, .02, and .005, respectively). Creatinine level was higher in patients with T2DM (P = .04) who were also less likely to have identifiable precipitating causes (P = .02). Hemoglobin A(1c) level was higher in patients with new-onset diabetes (P < .05), but did not differ between those with T1DM and T2DM. Mortality, which was 2%, occurred only in the African Americans with T2DM. We conclude that DKA is an important mode of initial presentation of T2DM, with new-onset T2DM accounting for about 60% of all new cases of DKA. African American patients with T2DM, in comparison with the Hispanic patients, are more susceptible to developing DKA. Diabetic ketoacidosis could occur in T2DM without any identifiable precipitant. The rising incidence of DKA may be attributable to its increasing occurrence in T2DM; therefore, measures aimed at primary prevention of T2DM are worthwhile.