Cardio-renal-metabolic disease in primary care setting

In the primary care setting providers have more tools available than ever before to impact positively obesity, diabetes, and their complications, such as renal and cardiac diseases. It is important to recognise what is available for treatment taking into account diabetes heterogeneity. For those who develop type 2 diabetes (T2DM), effective treatments are available that for the first time have shown a benefit in reducing mortality and macrovascular complications, in addition to the well-established benefits of glucose control in reducing microvascular complications. Some of the newer medications for treating hyperglycaemia have also a positive impact in reducing heart failure (HF). Technological advances have also contributed to improving the quality of care in patients with diabetes. The use of technology, such as continuous glucose monitoring systems (CGM), has improved significantly glucose and glycated haemoglobin A1c (HbA1c) values, while limiting the frequency of hypoglycaemia. Other technological support derives from the use of predictive algorithms that need to be refined to help predict those subjects who are at great risk of developing the disease and/or its complications, or who may require care by other specialists. In this review we also provide recommendations for the optimal use of the new medications; sodium-glucose co-transporter-2 inhibitors (SGLT2i) and Glucagon-like peptide-receptor agonists 1 (GLP1RA) in the primary care setting considering the relevance of these drugs for the management of T2DM also in its early stage.

Understanding diabetes heterogeneity: key steps towards precision medicine in diabetes

Diabetes is a highly heterogeneous condition; yet, it is diagnosed by measuring a single blood-borne metabolite, glucose, irrespective of aetiology. Although pragmatically helpful, disease classification can become complex and limit advances in research and medical care. Here, we describe diabetes heterogeneity, highlighting recent approaches that could facilitate management by integrating three disease models across all forms of diabetes, namely, the palette model, the threshold model and the gradient model. Once diabetes has developed, further worsening of established diabetes and the subsequent emergence of diabetes complications are kept in check by multiple processes designed to prevent or circumvent metabolic dysfunction. The impact of any given disease risk factor will vary from person-to-person depending on their background, diabetes-related propensity, and environmental exposures. Defining the consequent heterogeneity within diabetes through precision medicine, both in terms of diabetes risk and risk of complications, could improve health outcomes today and shine a light on avenues for novel therapy in the future.

First-in-human, double-blind, randomized phase 1b study of peptide immunotherapy IMCY-0098 in new-onset type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is a CD4⁺ T cell-driven autoimmune disease characterized by the destruction of insulin-producing pancreatic β-cells by CD8⁺ T cells. Achieving glycemic targets in T1D remains challenging in clinical practice; new treatments aim to halt autoimmunity and prolong β-cell survival. IMCY-0098 is a peptide derived from human proinsulin that contains a thiol-disulfide oxidoreductase motif at the N-terminus and was developed to halt disease progression by promoting the specific elimination of pathogenic T cells.

METHODS

This first-in-human, 24-week, double-blind phase 1b study evaluated the safety of three dosages of IMCY-0098 in adults diagnosed with T1D < 6 months before study start. Forty-one participants were randomized to receive four bi-weekly injections of placebo or increasing doses of IMCY-0098 (dose groups A/B/C received 50/150/450 μg for priming followed by three further administrations of 25/75/225 μg, respectively). Multiple T1D-related clinical parameters were also assessed to monitor disease progression and inform future development. Long-term follow-up to 48 weeks was also conducted in a subset of patients.

RESULTS

Treatment with IMCY-0098 was well tolerated with no systemic reactions; a total of 315 adverse events (AEs) were reported in 40 patients (97.6%) and were related to study treatment in 29 patients (68.3%). AEs were generally mild; no AE led to discontinuation of the study or death. No significant decline in C-peptide was noted from baseline to Week 24 for dose A, B, C, or placebo (mean change - 0.108, - 0.041, - 0.040, and - 0.012, respectively), suggesting no disease progression.

CONCLUSIONS

Promising safety profile and preliminary clinical response data support the design of a phase 2 study of IMCY-0098 in patients with recent-onset T1D.

TRIAL REGISTRATION

IMCY-T1D-001: ClinicalTrials.gov NCT03272269; EudraCT: 2016-003514-27; and IMCY-T1D-002: ClinicalTrials.gov NCT04190693; EudraCT: 2018-003728-35.

Combination therapy with saxagliptin and vitamin D for the preservation of β-cell function in adult-onset type 1 diabetes: a multi-center, randomized, controlled trial

Disease modifying therapies aiming to preserve β-cell function in patients with adult-onset autoimmune type 1 diabetes are lacking. Here, we conducted a multi-centre, randomized, controlled trial to assess the β-cell preservation effects of saxagliptin alone and saxagliptin combined with vitamin D as adjunctive therapies in adult-onset autoimmune type 1 diabetes. In this 3-arm trial, 301 participants were randomly assigned to a 24-month course of the conventional therapy (metformin with or without insulin) or adjunctive saxagliptin or adjunctive saxagliptin plus vitamin D to the conventional therapy. The primary endpoint was the change from baseline to 24 months in the fasting C-peptide. The secondary endpoints included the area under the concentration-time curve (AUC) for C-peptide level in a 2-h mixed-meal tolerance test, glycemic control, total daily insulin use and safety, respectively. The primary endpoint was not achieved in saxagliptin plus vitamin D group (P = 0.18) and saxagliptin group (P = 0.26). However, compared with the conventional therapy, 2-h C-peptide AUC from 24 months to baseline decreased less with saxagliptin plus vitamin D (-276 pmol/L vs. -419 pmol/L; P = 0.01), and not to the same degree with saxagliptin alone (-314 pmol/L; P = 0.14). Notably, for participants with higher glutamic acid decarboxylase antibody (GADA) levels, the decline of β-cell function was much lower in saxagliptin plus vitamin D group than in the conventional therapy group (P = 0.001). Insulin dose was significantly reduced in both active treatment groups than in the conventional therapy group despite all groups having similar glycemic control. In conclusion, the combination of saxagliptin and vitamin D preserves pancreatic β-cell function in adult-onset autoimmune type 1 diabetes, an effect especially efficacious in individuals with higher GADA levels. Our results provide evidence for a novel adjunct to insulin and metformin as potential initial treatment for adult-onset type 1 diabetes. (ClinicalTrials.gov identifier: NCT02407899).

Adult-onset type 1 diabetes: A changing perspective

Type 1 diabetes most commonly presents in adulthood, contrary to the widely held view that it is a disease of childhood. Furthermore, a substantial proportion of cases of adult-onset type 1 diabetes does not require insulin therapy at clinical onset. Recent studies have emphasised the evidence that adult-onset type 1 diabetes is prevalent but often misclassified initially as type 2 diabetes (1, 2). In this review, we discuss that recent literature, highlighting the similarities and differences between adult-onset and childhood-onset type 1 diabetes, exploring recent debates surrounding its epidemiology and genetics, as well as expanding on important issues of diagnostic criteria for individuals presenting with adult-onset diabetes and the subsequent management once identified as having an autoimmune basis. In addition, this review looks at the psychosocial challenges faced by T1D patients and their possible management.

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.

Genetic Discrimination Between LADA and Childhood-Onset Type 1 Diabetes Within the MHC

OBJECTIVE

The MHC region harbors the strongest loci for latent autoimmune diabetes in adults (LADA); however, the strength of association is likely attenuated compared with that for childhood-onset type 1 diabetes. In this study, we recapitulate independent effects in the MHC class I region in a population with type 1 diabetes and then determine whether such conditioning in LADA yields potential genetic discriminators between the two subtypes within this region.

RESEARCH DESIGN AND METHODS

Chromosome 6 was imputed using SNP2HLA, with conditional analysis performed in type 1 diabetes case subjects (n = 1,985) and control subjects (n = 2,219). The same approach was applied to a LADA cohort (n = 1,428) using population-based control subjects (n = 2,850) and in a separate replication cohort (656 type 1 diabetes case, 823 LADA case, and 3,218 control subjects).

RESULTS

The strongest associations in the MHC class II region (rs3957146, β [SE] = 1.44 [0.05]), as well as the independent effect of MHC class I genes, on type 1 diabetes risk, particularly HLA-B*39 (β [SE] = 1.36 [0.17]), were confirmed. The conditional analysis in LADA versus control subjects showed significant association in the MHC class II region (rs3957146, β [SE] = 1.14 [0.06]); however, we did not observe significant independent effects of MHC class I alleles in LADA.

CONCLUSIONS

In LADA, the independent effects of MHC class I observed in type 1 diabetes were not observed after conditioning on the leading MHC class II associations, suggesting that the MHC class I association may be a genetic discriminator between LADA and childhood-onset type 1 diabetes.

The Genetic Architecture of Type 1 Diabetes

Type 1 diabetes (T1D) is classically characterised by the clinical need for insulin, the presence of disease-associated serum autoantibodies, and an onset in childhood. The disease, as with other autoimmune diseases, is due to the interaction of genetic and non-genetic effects, which induce a destructive process damaging insulin-secreting cells. In this review, we focus on the nature of this interaction, and how our understanding of that gene-environment interaction has changed our understanding of the nature of the disease. We discuss the early onset of the disease, the development of distinct immunogenotypes, and the declining heritability with increasing age at diagnosis. Whilst Human Leukocyte Antigens (HLA) have a major role in causing T1D, we note that some of these HLA genes have a protective role, especially in children, whilst other non-HLA genes are also important. In adult-onset T1D, the disease is often not insulin-dependent at diagnosis, and has a dissimilar immunogenotype with reduced genetic predisposition. Finally, we discuss the putative nature of the non-genetic factors and how they might interact with genetic susceptibility, including preliminary studies of the epigenome associated with T1D.

Preclinical carotid atherosclerosis in patients with latent autoimmune diabetes in adults (LADA), type 2 diabetes and classical type 1 diabetes

BACKGROUND

LADA is probably the most prevalent form of autoimmune diabetes. Nevertheless, there are few data about cardiovascular disease in this group of patients. The aim of this study was to investigate the frequency of carotid atherosclerotic plaques in patients with LADA as compared with patients with classic type 1 diabetes and type 2 diabetes.

METHODS

Patients with LADA were matched for age and gender in different proportions to patients with type 2 diabetes, and classic type 1 diabetes. None of the patients had clinical cardiovascular disease. All subjects underwent B-mode carotid ultrasound to detect atheroma plaques. Demographics were obtained from all subjects.

RESULTS

We included 71 patients with LADA, 191 patients with type 2 diabetes and 116 patients with type 1 diabetes. Carotid atherosclerosis was more frequent in patients with LADA compared with type 2 diabetes (73.2% vs. 56.9%, P = 0.0018) and classic type 1 diabetes (57.1%, P = 0.026); these changes occurred despite healthier macrovascular risk profiles in the former. Age (P < 0.001), smoking (P = 0.003) and hypertension (P = 0.019) were independently associated with carotid atherosclerosis. Multiple plaques were also more frequent in patients with LADA as compared with classic type 1 diabetes and type 2 diabetes (45.1% and 33.6% vs. 27.2%, respectively, P = 0.022). The frequency of carotid plaques increased with increasing diabetes duration in LADA patients compared with type 2 diabetes (85.7% vs. 58.8%, inverse OR 5.72 [1.5-21.8]; P = 0.009).

CONCLUSIONS

LADA patients do not present with less carotid atherosclerosis than patients with type 1 and type 2 diabetes. Their macrovascular risk occurs despite a healthier macrovascular risk profile than those patients with type 2 diabetes.

Relative contribution of type 1 and type 2 diabetes loci to the genetic etiology of adult-onset, non-insulin-requiring autoimmune diabetes

BACKGROUND

In adulthood, autoimmune diabetes can present as non-insulin-requiring diabetes, termed as 'latent autoimmune diabetes in adults' (LADA). In this study, we investigated established type 1 diabetes (T1D) and type 2 diabetes (T2D) genetic loci in a large cohort of LADA cases to assess where LADA is situated relative to these two well-characterized, classic forms of diabetes.

METHODS

We tested the association of T1D and T2D GWAS-implicated loci in 978 LADA cases and 1057 non-diabetic controls of European ancestry using a linear mixed model. We then compared the associations of T1D and T2D loci between LADA and T1D and T2D cases, respectively. We quantified the difference in genetic risk between each given disease at each locus, and also calculated genetic risk scores to quantify how genetic liability to T1D and T2D distinguished LADA cases from controls.

RESULTS

Overall, our results showed that LADA is genetically more similar to T1D, with the exception of an association at the T2D HNF1A locus. Several T1D loci were associated with LADA, including the major histocompatibility complex region, as well as at PTPN22, SH2B3, and INS. Contrary to previous studies, the key T2D risk allele at TCF7L2 (rs7903146-T) had a significantly lower frequency in LADA cases, suggesting that this locus does not play a role in LADA etiology. When constrained on antibody status, the similarity between LADA and T1D became more apparent; however, the HNF1A and TCF7L2 observations persisted.

CONCLUSION

LADA is genetically closer to T1D than T2D, although the genetic load of T1D risk alleles is less than childhood-onset T1D, particularly at the major histocompatibility complex region, potentially accounting for the later disease onset. Our results show that the genetic spectrum of T1D extends into adult-onset diabetes, where it can clinically masquerade as T2D. Furthermore, T2D genetic risk plays a small role in LADA, with a degree of evidence for the HNF1A locus, highlighting the potential for genetic risk scores to contribute towards defining diabetes subtypes.

Inverse Relationship Between Organ-Specific Autoantibodies and Systemic Immune Mediators in Type 1 Diabetes and Type 2 Diabetes: Action LADA 11

OBJECTIVE

We related organ-specific autoantibodies, including diabetes-associated autoantibodies (DAAs) and non-DAAs to systemic cytokines/chemokines in type 1 and type 2 diabetes.

RESEARCH DESIGN AND METHODS

From the European Action LADA (latent autoimmune diabetes in adults) cohort, patients with adult-onset type 1 diabetes (n = 80, of whom 50 had LADA and 30 had classic type 1 diabetes) and type 2 diabetes (n = 626) were analyzed for DAAs (GAD antibody [GADA], IA-2 antigen, islet cell antibody, and zinc transporter T8), non-DAAs (transglutaminase, thyroid peroxide autoantibodies, parietal cell antibodies), and 10 immune mediator concentrations (measured by LUMINEX).

RESULTS

Type 1 diabetes patients (whether having classic type 1 diabetes or LADA), apart from their clinical phenotype, could not be distinguished by either autoantibodies (both DAAs and non-DAAs) or immune mediators. In type 1 diabetes, most immune mediators (9 of 10) were negatively correlated with DAA titers. Type 2 diabetes patients, who by definition were without DAAs, had fewer non-DAAs (P < 0.0005), but had higher levels of proinflammatory immune mediators, especially compared with patients with type 1 diabetes who had high GADA titers (interleukin [IL]-6 [P < 0.001], soluble E-selectin [P < 0.01], and IL-1 receptor antagonist [P = 0.052], for trend).

CONCLUSIONS

Patients with type 1 diabetes had more DAAs and non-DAAs than did those with type 2 diabetes, whereas the frequency and nature of these autoantibodies was broadly similar in classic type 1 diabetes and LADA. Systemic immune mediator levels, in the main, were negatively correlated with DAA titers, and, for some, were higher in patients with type 2 diabetes, especially when compared with patients who had high GADA titers. Differences in the clinical classification of diabetes are associated with graded differences in adaptive and innate immune reactivity.

BMI is an important driver of β-cell loss in type 1 diabetes upon diagnosis in 10 to 18-year-old children

OBJECTIVE

Body weight-related insulin resistance probably plays a role in progression to type 1 diabetes, but has an uncertain impact following diagnosis. In this study, we investigated whether BMI measured at diagnosis was an independent predictor of C-peptide decline 1-year post-diagnosis.

DESIGN

Multicentre longitudinal study carried out at diagnosis and up to 1-year follow-up.

METHODS

Data on C-peptide were collected from seven diabetes centres in Europe. Patients were grouped according to age at diagnosis (<5 years, n=126; >5 years <10 years, n=295; >10 years <18 years, n=421; >18 years, n=410). Linear regression was used to investigate whether BMI was an independent predictor of change in fasting C-peptide over 1 year. Models were additionally adjusted for baseline insulin dose and HbA1c.

RESULTS

In individuals diagnosed between 0 and 5 years, 5 and 10 years and those diagnosed >18 years, we found no association between BMI and C-peptide decline. In patients aged 10-18 years, higher BMI at baseline was associated with a greater decline in fasting C-peptide over 1 year with a decrease (β 95% CI; P value) of 0.025 (0.010, 0.041) nM/kg per m(2) higher baseline BMI (P=0.001). This association remained significant after adjusting for gender and differences in HbA1c and insulin dose (β=0.026, 95% CI=0.0097, 0.042; P=0.002).

CONCLUSIONS

These observations indicate that increased body weight and increased insulin demand are associated with more rapid disease progression after diagnosis of type 1 diabetes in an age group 10-18 years. This should be considered in studies of β-cell function in type 1 diabetes.

Similar weight-adjusted insulin secretion and insulin sensitivity in short-duration late autoimmune diabetes of adulthood (LADA) and type 2 diabetes: Action LADA 9 [corrected]

AIMS

To explore insulin sensitivity and insulin secretion in people with latent autoimmune diabetes in adulthood (LADA) compared with that in people with type 2 diabetes.

METHODS

A total of 12 people with LADA, defined as glutamic acid decarboxylase (GAD) antibody positivity and > 1 year of insulin independency (group A) were age-matched pairwise to people with type 2 diabetes (group B) and to six people with type 2 diabetes of similar age and BMI (group C). β-Cell function (first-phase insulin secretion and assessment of insulin pulsatility), insulin sensitivity (hyperinsulinemic-euglycemic clamp) and metabolic response during a mixed meal were studied.

RESULTS

Both first-phase insulin secretion and insulin release during the meal were greater (P = 0.05 and P = 0.009, respectively) in type 2 diabetes as compared with LADA; these differences were lost on adjustment for BMI (group C) and could be explained by BMI alone in a multivariate analysis. Neither insulin pulsatility, incretin secretion nor insulin sensitivity differed among the groups.

CONCLUSIONS

We found no evidence that LADA and type 2 diabetes were distinct disease entities beyond the differences explained by BMI.

LADA and CARDS: a prospective study of clinical outcome in established adult-onset autoimmune diabetes

OBJECTIVE

Diabetes-associated autoantibodies can be detected in adult-onset diabetes, even when initially non-insulin requiring, i.e., with latent autoimmune diabetes. We aimed to identify adult-onset autoimmune diabetes in patients with established "type 2 diabetes" participating in the Collaborative Atorvastatin Diabetes Study (CARDS) to characterize their phenotype and clinical outcome.

RESEARCH DESIGN AND METHODS

We prospectively studied 2,425 European patients with presumed type 2 diabetes (mean age 62 years, diabetes duration 7.9 years) for outcomes at 3.9 years after randomization to either atorvastatin or placebo. Subjects were screened for autoantibodies to GAD (GADA), insulinoma-associated antigen-2 (IA-2A), and zinc-transporter 8 (ZnT8A).

RESULTS

A total of 173 patients (7.1%) had GADA, of whom 11 (0.5%) and 5 (0.2%) were also positive for IA-2A and ZnT8A, respectively. At baseline, 44% of GADA-positive patients were not on insulin. Fewer autoantibody-positive than autoantibody-negative patients had metabolic syndrome (64 vs. 80%), and more were on insulin (56 vs. 17%) (P < 0.0001 for each) without lower HbA1c (69 mmol/mol [8.5%] vs. 62 mmol/mol [7.8%]). The frequency of microvascular and macrovascular events was similar in both cohorts, independent of atorvastatin.

CONCLUSIONS

Adult-onset autoimmune diabetes was prevalent, even in patients with established diabetes presumed to have type 2 diabetes. After 11.8 years' diabetes duration, nearly half the patients with autoimmune diabetes were not on insulin treatment and almost two-thirds had metabolic syndrome. The type of diabetes, whether autoimmune diabetes or type 2 diabetes, did not impact the risk of microvascular disease.

Age-dependent decline of β-cell function in type 1 diabetes after diagnosis: a multi-centre longitudinal study

AIMS

C-peptide secretion is currently the only available clinical biomarker to measure residual β-cell function in type 1 diabetes. However, the natural history of C-peptide decline after diagnosis can vary considerably dependent upon several variables. We investigated the shape of C-peptide decline over time from type 1 diabetes onset in relation to age at diagnosis, haemoglobin A1c (HbA1c) levels and insulin dose.

METHODS

We analysed data from 3929 type 1 diabetes patients recruited from seven European centres representing all age groups at disease onset (childhood, adolescence and adulthood). The influence of the age at onset on β-cell function was investigated in a longitudinal analysis at diagnosis and up to 5-years follow-up.

RESULTS

Fasting C-peptide (FCP) data at diagnosis were available in 3668 patients stratified according to age at diagnosis in four groups (<5 years, n = 344; >5 years < 10 years, n = 668; >10 years < 18 years, n = 991; >18 years, n = 1655). FCP levels were positively correlated with age (p < 0.001); the subsequent decline in FCP over time was log-linear with a greater decline rate in younger age groups (p < 0.0001).

CONCLUSIONS

This study reveals a positive correlation between age at diagnosis of type 1 diabetes and FCP with a more rapid decline of β-cell function in the very young patients. These data can inform the design of clinical trials using C-peptide values as an end-point for the effect of a given treatment.

Personalizing guidelines for diabetes management: twilight or dawn of the expert?

BACKGROUND

This opinion article on the management of type 2 diabetes considers the old and new format of guidelines and critical changes in the character of such guidelines. We highlight limitations of the guidelines and make recommendations for how treatment can be more personalised.

DISCUSSION

Published guidelines for the management of adult-onset non-insulin requiring diabetes have adopted a formulaic approach to patient management that can be overseen centrally and delivered by personnel with limited training. Recently, guidelines have taken a patient-centered, multiple risk-factor approach. Importantly, local funding issues are considered, but drive the final action and not the decision-making process. The nature of the disease can be determined by laboratory tests, including screening for diabetes-associated autoantibodies. The strategy remains step-up, with intensification of drug or insulin dose. As with past guidelines, there is an assumption that in each patient with type 2 diabetes, metformin is used initially, but targets and therapies then veer in different directions to create a matrix of options based on the features and responses of each individual. Factors to consider include: (A)ge, (B)ody weight, (C)omplications and co-morbidities, Diabetes (D)uration and (E)xpense, but also patient preference and patient response.

SUMMARY

Guidelines for the management of type 2 diabetes have important limitations and a patient-centered, multiple target, multiple therapy approach is proposed.

Adult-onset autoimmune diabetes in Europe is prevalent with a broad clinical phenotype: Action LADA 7

OBJECTIVE

Specific autoantibodies characterize type 1 diabetes in childhood but are also found in adult-onset diabetes, even when initially non-insulin requiring, e.g., with latent autoimmune diabetes (LADA). We aimed to characterize adult-onset autoimmune diabetes.

RESEARCH DESIGN AND METHODS

We consecutively studied 6,156 European diabetic patients attending clinics within 5 years of diagnosis (age range, 30-70 years) examined cross-sectionally clinically and for GAD antibodies (GADA) and antibodies to insulinoma-associated antigen-2 (IA-2A) and zinc-transporter 8 (ZnT8A).

RESULTS

Of 6,156 patients, 541 (8.8%) had GADA and only 57 (0.9%) IA-2A or ZnT8A alone. More autoantibody-positive than autoantibody-negative patients were younger, leaner, on insulin (49.5 vs. 13.2%), and female (P < 0.0001 for each), though LADA patients (9.7% of total) did not show categorically distinct clinical features from autoantibody-negative type 2 diabetes. Similarly, more GADA patients with high (>200 World Health Organization IU) (n = 403) compared with low (n = 138) titer were female, lean, and insulin treated (54.6 vs. 39.7%) (P < 0.02 for each). Autoantibody-positive patients usually had GADA (541 of 598; 90.5%) and had LADA more often than type 1 autoimmune diabetes (odds ratio 3.3).

CONCLUSIONS

Adult-onset autoimmune diabetes emerges as a prevalent form of autoimmune diabetes. Our results indicate that adult-onset autoimmune diabetes in Europe encompasses type 1 diabetes and LADA in the same broad clinical and autoantibody-positive spectrum. At diagnosis, patients with adult-onset autoimmune diabetes are usually non-insulin requiring and clinically indistinguishable from patients with type 2 diabetes, though they tend to be younger and leaner. Only with screening for autoantibodies, especially GADA, can they be identified with certainty.

The broad clinical phenotype of Type 1 diabetes at presentation

Immune-mediated (auto-immune) Type 1 diabetes mellitus is not a homogenous entity, but nonetheless has distinctive characteristics. In children, it may present with classical insulin deficiency and ketoacidosis at disease onset, whereas autoimmune diabetes in adults may not always be insulin dependent. Indeed, as the adult-onset form of autoimmune diabetes may resemble Type 2 diabetes, it is imperative to test for diabetes-associated autoantibodies to establish the correct diagnosis. The therapeutic response can be predicted by measuring the levels of autoantibodies to various islet cell autoantigens, such as islet cell antibodies (ICA), glutamate decarboxylase 65 (GAD65), insulin, tyrosine phosphatase (IA-2) and IA-2β, and zinc transporter 8 (ZnT8) and evaluating β-cell function. A high risk of progression to insulin dependency is associated with particular genetic constellations, such as human leukocyte antigen risk alleles, young age at onset, the presence of multiple autoantibodies, including high titres of anti-GAD antibodies; such patients should be offered early insulin replacement therapy, as they respond poorly to diet and oral hypoglycaemic drug therapy. Hence, considering the broad spectrum of phenotypes seen in adult-onset diabetes, treatment targets can only be reached by identification of immune-mediated cases, as their management differs from those with classical Type 2 diabetes.

A 2-year prospective randomized controlled trial of intravitreal bevacizumab or laser therapy (BOLT) in the management of diabetic macular edema: 24-month data: report 3

OBJECTIVE

To report the 2-year outcomes of the BOLT study, a prospective randomized controlled trial evaluating intravitreous bevacizumab and modified Early Treatment Diabetic Retinopathy Study (ETDRS) macular laser therapy (MLT) in patients with persistent clinically significant macular edema (CSME).

METHODS

In a 2-year, single-center, randomized controlled trial, 80 patients with center-involving CSME and visual acuity of 20/40 to 20/320 were randomized to receive either bevacizumab or MLT.

MAIN OUTCOME MEASURES

PRIMARY OUTCOME

difference in ETDRS best-corrected visual acuity (BCVA) between arms.

SECONDARY OUTCOMES

mean change in BCVA, proportion gaining at least 15 and at least 10 ETDRS letters, losing fewer than 15 and at least 30 letters, change in central macular thickness, ETDRS retinopathy severity, and safety outcomes.

RESULTS

At 2 years, mean (SD) ETDRS BCVA was 64.4 (13.3) (ETDRS equivalent Snellen fraction: 20/50) in the bevacizumab arm and 54.8 (12.6) (20/80) in the MLT arm (P=.005). The bevacizumab arm gained a median of 9 ETDRS letters vs 2.5 letters for MLT (P=.005), with a mean gain of 8.6 letters for bevacizumab vs amean loss of 0.5 letters for MLT. Forty-nine percent of patients gained 10 or more letters (P=.001) and 32% gained at least 15 letters (P=.004) for bevacizumab vs 7% and 4% for MLT. Percentage who lost fewer than 15 letters in the MLT arm was 86% vs 100% for bevacizumab (P=.03). Mean reduction in central macular thickness was 146 μm in the bevacizumab arm vs 118 μm in the MLT arm. The median number of treatments over 24 months was 13 for bevacizumab and 4 for MLT.

CONCLUSIONS

This study provides evidence supporting longer-term use of intravitreous bevacizumab for persistent center-involving CSME.

APPLICATION TO CLINICAL PRACTICE

Improvements in BCVA and central macular thickness seen with bevacizumab at 1 year were maintained over the second year with a mean of 4 injections.

TRIAL REGISTRATION

eudract.ema.europa.eu Identifier: 2007-000847-89

Guts, germs, and meals: the origin of type 1 diabetes

Type 1 diabetes mellitus (T1DM) is due, in part, to non-genetically determined factors including environmental factors. The nature of these environmental effects remains unclear but they are important to identify since they may be amenable to therapy. Recently, the gut microbiota, the trillions of microorganisms inhabiting the gut, as well as diet, have been implicated in T1DM pathogenesis. Since dietary changes can reshape this complex gut community, its co-evolution could have been altered by changes to our diet, agriculture, personal hygiene, and antibiotic usage, which coincide with the increased incidence of T1DM. Recent studies demonstrate an association between altered gut microbiota and T1DM in both T1DM patients and animal models of the disease. Further studies should provide new insight into those critical host-microbial interactions, potentially suggesting new diagnostic or therapeutic strategies for disease prevention.

Monocyte gene-expression profiles associated with childhood-onset type 1 diabetes and disease risk: a study of identical twins

OBJECTIVE

Monocytes in childhood-onset type 1 diabetes show distinct gene expression. We hypothesize that monocyte activation in monozygotic (MZ) twin pairs discordant for childhood-onset type 1 diabetes could reflect distinct stages of the disease process including diabetes susceptibility (differences between twins, both diabetic and nondiabetic, and control subjects) and/or disease progression (differences between diabetic and nondiabetic twins).

RESEARCH DESIGN AND METHODS

We studied patterns of inflammatory gene expression in peripheral blood monocytes of MZ twin pairs (n = 10 pairs) discordant for childhood-onset type 1 diabetes, normal control twin pairs (n = 10 pairs), and healthy control subjects (n = 51) using quantitative-PCR (Q-PCR). We tested the 24 genes previously observed by whole genome analyses and verified by Q-PCR in autoimmune diabetes and performed a hierarchical cluster analysis.

RESULTS

Of 24 genes abnormally expressed in childhood-onset type 1 diabetes, we revalidated abnormal expression in 16 of them in diabetic twins including distinct sets of downregulated (P < 0.03) and upregulated (P < 0.02) genes. Of these 16 genes, 13 were abnormally expressed in nondiabetic twins, implicating these genes in diabetes susceptibility (P < 0.044 for all). Cluster analysis of monocyte gene-expression in nondiabetic twins identified two distinct, mutually exclusive clusters, while diabetic twins had a network of positively correlated genes.

CONCLUSIONS

Patients with childhood-onset type 1 diabetes show abnormal monocyte gene-expression levels with an altered gene-expression network due to gene-environment interaction. Importantly, perturbed gene-expression clusters were also detected in nondiabetic twins, implicating monocyte abnormalities in susceptibility to diabetes.

Altered monocyte cyclo-oxygenase response in non-obese diabetic mice

Monocytes infiltrate islets in non-obese diabetic (NOD) mice. Activated monocyte/macrophages express cyclo-oxygenase-2 (COX-2) promoting prostaglandin-E(2) (PGE(2)) secretion, while COX-1 expression is constitutive. We investigated in female NOD mice: (i) natural history of monocyte COX expression basally and following lipopolysaccharide (LPS) stimulation; (ii) impact of COX-2 specific inhibitor (Vioxx) on PGE(2), insulitis and diabetes. CD11b(+) monocytes were analysed for COX mRNA expression from NOD (n = 48) and C57BL/6 control (n = 18) mice. NOD mice were treated with either Vioxx (total dose 80 mg/kg) (n = 29) or methylcellulose as control (n = 29) administered by gavage at 4 weeks until diabetes developed or age 30 weeks. In all groups, basal monocyte COX mRNA and PGE(2) secretion were normal, while following LPS, after 5 weeks of age monocyte/macrophage COX-1 mRNA decreased (P < 0.01) and COX-2 mRNA increased (P < 0.01). However, diabetic NOD mice had reduced COX mRNA response (P = 0.03). Vioxx administration influenced neither PGE(2), insulitis nor diabetes. We demonstrate an isoform switch in monocyte/macrophage COX mRNA expression following LPS, which is altered in diabetic NOD mice as in human diabetes. However, Vioxx failed to affect insulitis or diabetes. We conclude that monocyte responses are altered in diabetic NOD mice but COX-2 expression is unlikely to be critical to disease risk.

Lack of effect of vitamin D administration during pregnancy and early life on diabetes incidence in the non-obese diabetic mouse

BACKGROUND AND AIMS

Several studies have suggested that vitamin D supplementation in early life may reduce the risk of developing type 1 diabetes in later life. The non-obese diabetic (NOD) mouse is a model of spontaneous type 1 diabetes currently used for testing hypothesis/compounds aimed at disease prevention. In this study, we tested the effect of vitamin D (16 IU by gavage) on diabetes incidence in NOD/Ba mice treated from conception with olive oil containing vitamin D via maternal dosing up to 10 weeks of age and followed up until 32 weeks of age.

METHODS

Twelve breeding pairs were administered olive oil containing vitamin D during pregnancy, 15 days following the birth of the pups and for the next 10 weeks subsequently. The same breeding pairs were bred again after a clearance period of 15 days using a control solution to produce a control litter. This control group received a control solution for the same period of time. Diabetes incidence, degree of insulitis, and insulin content in the pancreas were investigated in the two groups.

RESULTS

12 vitamin D-treated NOD mice developed diabetes compared to 15 animals in the control group (Log rank test p = 0.899, NS). There were no significant differences between the groups in diabetes incidence, time of onset of the disease, degree of insulitis, or the insulin content in the pancreas.

CONCLUSION

Vitamin D administered in utero and in the early stages of life at the dosage used does not change the incidence of diabetes or modify the disease process that leads to beta cell destruction in the NOD mouse.

HbA(1c) levels are genetically determined even in type 1 diabetes: evidence from healthy and diabetic twins

HbA(1c), a measure of blood glucose regulation, reflects glucose levels in the preceding months. In diabetes, HbA(1c) levels predict the risk of microvascular complications. The aim of this study was to determine whether genetic factors could influence HbA(1c) levels in normal subjects and type 1 diabetic patients. We performed a classical twin study of HbA(1c) in healthy nondiabetic female twins and 42 monozygotic (MZ) and 47 dizygotic (DZ) pairs. Interclass correlations (r) were higher in MZ (r = 0.77) compared with DZ (r = 0.53) twin pairs, suggesting a substantial genetic effect; this was confirmed by quantitative genetic model fitting. Additive genetic effects (heritability) explained 62% (95% CI 47-75) of population variance in HbA(1c); the remainder was attributable to the influence of unique environment (23% [15-36]) and age (14% [5-28]). Multivariate modeling showed that genetic factors also have a substantial influence on fasting glucose levels (51%). However, HbA(1c) heritability could not be explained by genes in common with fasting glucose. In the patients with type 1 diabetes, HbA(1c) levels were correlated in 33 MZ twins concordant for diabetes (r = 0.68; P < 0.001) but also in 45 MZ twins discordant for the disease (r = 0.52; P < 0.001). These significant correlations for HbA(1c) in both concordant and discordant pairs indicate a diabetes-independent familial effect. Thus, HbA(1c) levels are largely genetically determined and independent of the genes influencing fasting glucose. Even in type 1 diabetes, familial (i.e., diabetes-independent) factors influence protein glycation, implying that familial factors may explain, in part, the risk for microvascular complications, as indicated by high HbA(1c) levels.

Concordance for type 1 diabetes in identical twins is affected by insulin genotype

OBJECTIVE

Monozygotic twins are usually discordant (only one twin affected) for type 1 diabetes. Discordance for disease between such twins implies a role for nongenetically determined factors but could also be influenced by a decreased load of diabetes susceptibility genes. The aim of this study was to determine whether two susceptibility genes were less prevalent in discordant twins compared with concordant twins.

RESEARCH DESIGN AND METHODS

We studied 77 monozygotic twin pairs (INS), 40 concordant and 37 discordant, for type 1 diabetes at polymorphism of the insulin gene region on chromosome 11 p and HLA-DQBI.

RESULTS

The disease-associated INS genotype (Hph I) was identified in 87.5% of the concordant twins but only in 59.5% (P = 0.005) of the discordant twins. Neither DQB1*0201 nor DQB1*0302 was seen in 2 of 40 (5%) concordant twins compared with 8 of 37 (22%) discordant twins (P = 0.04). No statistical differences were seen between concordant and discordant twins at individual alleles of DQB1. Combining insulin and DQ data, 5% of concordant twins compared with 32.4% of discordant twins had neither DQB1*0201/DQB1*0302 nor the high-risk Hph I INS "++" genotype (P = 0.002).

CONCLUSIONS

We conclude that the possession of the high-risk Hph I insulin genotype increases the likelihood of identical twins being concordant for type 1 diabetes and that the "load" of both major histocompatibility complex (MHC) and non-MHC susceptibility genes has an impact on the disease penetrance of type 1 diabetes.

Heterogeneity of type I diabetes: analysis of monozygotic twins in Great Britain and the United States

AIMS

To determine the risk, hazard rate and factors affecting progression to diabetes in monozygotic twins of patients with Type I (insulin-dependent) diabetes mellitus.

METHODS

Prospective analysis was done of two cohorts of non-diabetic monozygotic twins of patients with Type I diabetes from Great Britain (n = 134) and the United States (n = 53).

RESULTS

The diabetes-free survival analysis was similar between both cohorts (p = 0.6). The combined survival analysis (n = 187, median follow-up = 17.7 years, range = 0.01-57) at 40 years of discordance estimated a 39% probability of diabetes for the initially discordant twin. Survival analysis with left truncation of data estimated that probability to be 50%. For twins who became concordant (n = 47), the median discordance time was 4.2 years (range 0.4 to 39), exceeding 15 years in 23.4%. Twins of probands diagnosed at 24 years of age or younger had a 38% probability of diabetes by 30 years of discordance, compared with 6% for twins of probands diagnosed after 24 years of age (p = 0.004). The twins of probands diagnosed before 15 years of age had the highest diabetes hazard rate in the first discordance year, decreasing thereafter. By survival analysis, diabetes risk was higher in twins who were heterozygous for DR3-DQ2 and DR4-DQ8 than in twins with neither DR3-DQ2 nor DR4-DQ8 (p < 0.05).

CONCLUSION/INTERPRETATION

Monozygotic twins of patients with Type I diabetes from two different countries had similar rates of progression to diabetes. Whereas most twins did not develop diabetes, 25% of the twins who progressed did so after more than 14 years of discordance. An age-related heterogeneity was observed, with higher progression to diabetes for twins of patients diagnosed at a younger age.

Effects of acute hyperglycaemia on cardiac function: an echocardiographic study of monozygotic twins

BACKGROUND

A major cause of morbidity in type I diabetes is congestive heart failure due predominantly to left ventricular diastolic dysfunction. The mechanism of diastolic dysfunction remains unknown and does not relate to blood pressure, microvascular complications and glycated haemoglobin. Hyperglycaemia is the hallmark of diabetes and is a potential determinant of left ventricular diastolic dysfunction.

OBJECTIVE

To determine whether acute hyperglycaemia can induce changes in left ventricular diastolic function in normal subjects similar to those observed in insulin-dependent diabetes mellitus (IDDM).

DESIGN

Cross-sectional study.

SETTING

London teaching hospital.

SUBJECTS

Sixteen twins from eight identical twin pairs discordant for IDDM (age 18-38 years, five male) were studied; none had a history or evidence of myocardial ischaemia, valvular or primary heart muscle disease, systemic hypertension or nephropathy.

INTERVENTIONS

Non-diabetic twins underwent a hyperglycaemic clamp at 10 mmol/l.

MAIN OUTCOME MEASURES

Doppler echocardiography was performed in basal condition in identical twin pairs discordant for IDDM and repeated in the non-diabetic twins during hyperglycaemia. Blood glucose, insulin and catecholamines were measured at baseline and during hyperglycaemia.

RESULTS

Transmitral Doppler E/A velocity ratio was significantly lower in diabetic than non-diabetic twins at baseline (1.44 (0.38) vs. 1.51 (0.19), P<0.05). Glucose infusion in the non-diabetic twins resulted in an increase in their E/A ratio (1.51 (0.19) vs. 1.82 (0. 47), P<0.05) due to an increase in E velocity (68 (12) to 64.7 (10. 7), P<0.05) and a decrease in the peak A velocity (42.7 (3.85) to 38. 0 (4.1), P<0.05). No significant changes were observed in peak E velocity or isovolumic relaxation time in the non-diabetic twins between baseline and hyperglycaemia.

CONCLUSIONS

The alterations in left ventricular diastolic function induced by acute hyperglycaemia and consequent increase in plasma catecholamines do not mimic those demonstrated in IDDM patients.

Immune reactivity to glutamic acid decarboxylase 65 in stiffman syndrome and type 1 diabetes mellitus

BACKGROUND

The immune response to an isoform of glutamic acid decarboxylase (GAD), GAD65, is associated with two clinically distinct diseases, stiff-man syndrome (SMS) and type 1 (insulin-dependent) diabetes mellitus. We sought to identify differences in the cellular and humoral immune responses to GAD in these two diseases.

METHODS

We compared T-cell responses in 14 SMS patients with axial disease and 17 patients with type 1 diabetes.

FINDINGS

Peripheral blood T cells of eight SMS patients recognised different immunodominant epitopes of GAD65 compared with T cells from 17 patients with type 1 diabetes. GAD regions 81-171 and 313-403 induced a dominant T-cell response in six of eight patients with SMS but in only one of 17 patients with type 1 diabetes (p=0.001). No SMS patients responded dominantly to GAD fragments 161-243 and 473-555 compared with ten patients with type 1 diabetes (p=0.008). GAD antibodies were detected in 11 of 14 SMS patients (seven with diabetes) and 11 of 17 patients with type 1 diabetes; IgG1 was dominant in both groups. SMS patients, however, were more likely than patients with diabetes to have isotypes other than IgG1 (p=0.03), in particular, IgG4 or IgE isotypes, which were not detected in patients with type 1 diabetes (p=0.012).

INTERPRETATION

Our findings indicate differences between patients with SMS and type 1 diabetes in cellular (epitope recognition) and humoral (isotype pattern) responses to GAD65. Thus the same autoantigen can elicit distinct immune responses in patients with SMS, even when associated with diabetes, compared with patients with type 1 diabetes.

Twins: mirrors of the immune system

Twin studies are a powerful tool to assess genetic and nongenetic factors in multifactorial, immune-mediated diseases. Here, Marco Salvetti and colleagues review important results from such studies and highlight their potential value. Future developments that should help to realize the potential of twin studies are discussed.

Nitric oxide synthesis and isoprostane production in subjects with type 1 diabetes and normal urinary albumin excretion

The role of nitric oxide (NO) and free radicals in the development of microvascular disease in type 1 diabetes remains unclear. We have measured NO and isoprostane (a stable marker of in vivo lipid peroxidation) production in 13 type 1 diabetic subjects with normal urinary albumin excretion and 13 healthy volunteers. Whole-body NO synthesis was quantified by measuring the urinary excretion of 15N-nitrate after the intravenous administration of L-[15N]2-arginine. The urinary excretion of the major urinary metabolite of 15-F2t-isoprostane (8-iso-prostaglandin-F2alpha), 2,3-dinor-5,6-dihydro-F2t-IsoP, was quantified as a marker of in vivo lipid peroxidation. Whole-body NO synthesis was significantly higher in diabetic subjects compared with control subjects (342 vs. 216 nmol 15N-nitrate/mmol creatinine [95% CI of the difference 45-207], P = 0.005). This increase was not explained by a difference in renal function between the 2 groups. There was no difference in 2,3-dinor-5,6-dihydro-F2t-IsoP excretion between diabetic subjects and control subjects (44.8+/-7.8 vs. 41.4+/-10.0 ng/mmol creatinine, mean +/- 95% CI). However, there was an inverse correlation between NO synthesis and free radical activity in subjects with diabetes (r = -0.62, P = 0.012) that was not observed in control subjects (r = 0.37, P = 0.107). We conclude that whole-body NO synthesis is higher in type 1 diabetic subjects with normal urinary albumin excretion than in control subjects. The inverse correlation between isoprostane production and NO synthesis in diabetic subjects is consistent with the hypothesis that NO is being inactivated by reactive oxygen species.

Proliferative responses to selected peptides of IA-2 in identical twins discordant for Type 1 diabetes

BACKGROUND

The aim of the study was to define T lymphocyte reactivity to selected peptides of an islet antigen IA-2, associated with Type 1 diabetes.

METHODS

We used 10 peptides selected from the IA-2 molecule due to their predicted ability to bind to HLA-DRB1*0401, a Type 1 diabetes-associated allele. We tested 21 identical twin pairs discordant for the disease and 15 control subjects and then followed them prospectively; seven non-diabetic twins developed diabetes.

RESULTS

Twins of identical pairs tended to respond to different peptides suggesting that the T cell response is, to a degree, shaped by non-genetically determined factors (p<0. 0001). However, there was no difference in the T cell responses between diabetic twins and either their non-diabetic identical twins or control subjects and the response was heterogenous. T cell responses did not differ in those seven non-diabetic twins who developed diabetes from those twins who did not. T cell responses to peptide 11 (amino acids 502-514) was immunodominant in diabetic twins as well as their non-diabetic twins and controls; responses were not correlated with HLA, IA-2 antibodies, age or duration of disease.

CONCLUSION

We conclude that T cell responses to selected IA-2 peptides are not genetically determined, heterogeneous, not strictly HLA controlled and did not distinguish diabetic or prediabetic twins from non-diabetic twins or controls. The identification of an immunodominant T cell response to IA-2 peptide 502-514 raises the possibility that this, or similar, epitopes may be of therapeutic value in disease prevention.

Antibodies to IA-2 and GAD65 in type 1 and type 2 diabetes: isotype restriction and polyclonality

OBJECTIVE

To determine the isotypes and clonality of antibodies to GAD (GADA) and IA-2 (IA-2A) in patients with type 1 and type 2 diabetes.

RESEARCH DESIGN AND METHODS

We studied the following consecutive series of patients who attended a diabetes center for antibodies to GADA and IA-2A: 52 newly diagnosed type 1 diabetic patients, 199 type 2 diabetic patients, 200 control patients, and a cohort of 34 nondiabetic identical twins of patients with type 1 diabetes (15 of whom developed diabetes) who were followed prospectively.

RESULTS

GADA or IA-2A were detected in 37 (71%) type 1 diabetic patients compared with only 10 (5%) type 2 diabetic patients (P<0.0001). Both GAD and IA-2 antibodies, regardless of the type of diabetes, were usually subclass restricted to IgG1 and were polyclonal. IgM, IgG3, and IgE isotypes were also detected, but all isotypes of GADA and IA-2A were less prevalent than IgG1 (P<0.017 for either antibody). There was no evidence of spreading or switching of isotypes before the onset of type 1 diabetes.

CONCLUSIONS

These observations suggest that the pathogenesis of antigen-specific antibodies in type 1 and type 2 diabetes is similar and probably involves a chronic nonrandom antigen-driven polyclonal B-cell activation that is consistent with a Th1-type immune response.

Cytokine secretion patterns in twins discordant for Type I diabetes

AIMS/HYPOTHESIS

The search for T-cell reactions that are associated with disease in Type I (insulin-dependent) diabetes mellitus is severely hampered because control groups cannot be matched for relevant immune response genes. We therefore compared T-cell responses between identical twins discordant for Type I diabetes.

METHODS

Pairs of monozygotic twins (n = 17) discordant for Type I diabetes were studied. Cultures were set up from whole blood immediately after sampling and cells were challenged with human recombinant hsp60, with the mitogen phytohaemagglutinin or with the staphylococcal superantigen. Supernatants were removed after 48 or 96 h and analysed for T-helper1 type cytokines interferon-gamma, TNFalpha and T-helper2 type cytokines IL-4, IL-10 by sandwich-ELISA.

RESULTS

The height of the T-helper1 type cytokine response to hsp60, phytohaemagglutinin or staphylococcal enterotoxin B did not show disease association, i. e. it was similar between discordant twins. In contrast, the production of T-helper2 type cytokines differed between discordant twins. The IL-10 response to hsp60 was higher in twins at low disease risk (islet cell antibody-negative) than in their diabetic cotwins (p < 0.01), as was the IL-4 response to phytohaemagglutinin (p < 0.05). No difference was seen in the cytokine response between islet cell antibody-positive twins and their diabetic cotwins.

CONCLUSIONS/INTERPRETATION

The data indicate an association between T-helper2 type cytokine secretion patterns and disease or disease risk.

Antibodies to GAD65 and a tyrosine phosphatase-like molecule IA-2ic in Filipino type 1 diabetic patients

OBJECTIVE

Type 1 diabetes is more prevalent in Europeans than it is in Asians. The disease is associated with autoantibodies to GAD65 and a protein tyrosine phosphatase-like molecule (IA-2). The frequency of GAD antibodies in Asian patients with type 1 diabetes may be lower than that in Europeans. No data are available on IA-2 antibodies in Asians. We tested antibodies to GAD65 and IA-2ic (the intracellular fragment containing the antibody epitope) in Filipino diabetic patients because this population has mixed European and aboriginal racial origins.

RESEARCH DESIGN AND METHODS

A cross-sectional study of antibodies to GAD65 and IA-2ic was performed on a consecutive series of 91 type 1 diabetic patients, 74 type 2 diabetic patients, and 100 control subjects attending a diabetes clinic in Manila, the Republic of the Philippines. All subjects were <40 years of age, with a mean age +/- SD of 24.8+/-9.8, 34.3+/-5.8, and 25.8+/-8.0 years, respectively. Diagnosis of type 1 diabetes was determined clinically and confirmed by baseline C-peptide.

RESULTS

Of 91 type 1 diabetic patients, antibodies to GAD65 were detected in 25 (27.4%), but antibodies to IA-2ic were found in only 8 (8.8%) (P = 0.002); neither autoantibody was detected in either the type 2 diabetic or control subjects. Of the 25 recently diagnosed type 1 diabetic patients (disease duration <2.0 years), autoantibodies to GAD65 were detected in 14 (56%), but those to IA-2ic in only 4 (16%) (P = 0.007); GAD65 antibodies were detected in only 4 (6%) of 66 patients with a longer disease duration (P = 0.0004). Comparison with recently diagnosed European type 1 diabetic patients of age and disease duration similar to that of the Filipinos indicated that IA-2ic antibodies, unlike GAD antibodies, were significantly less prevalent in Filipino type 1 diabetic patients (P = 0.0007).

CONCLUSIONS

This is the first study investigating the prevalence and pattern of humoral immune response in type 1 diabetic patients from the Philippines. Antibodies to IA-2ic, unlike GAD antibodies, were infrequent. Patterns of immune responses to type 1 diabetes-associated antigens may differ worldwide, with important implications for prediction of the disease and the potential for antigen-specific therapy.

Concordance rate for type II diabetes mellitus in monozygotic twins: actuarial analysis

To determine the concordance rate for Type II (non-insulin-dependent) diabetes mellitus in monozygotic twin pairs, initially ascertained discordant for diabetes, we carried out a prospective study on 44 non-diabetic subjects, each of whom had a sibling twin with diabetes (21 men, 23 women, median age 55 years, interquartile range 47-65). The subjects were referred as discordant for Type II diabetes. The twin pairs were part of the British Diabetic Twin Study and ascertained between May 1968 and January 1998. These subjects underwent an OGTT at time of referral and periodically thereafter. The mean follow-up was 8 years (range 0-18 years) and data were collected until January 1996. The percentage of twins who developed Type II diabetes was assessed by standard actuarial life-table methods and the pairwise concordance rate, that is the proportion of concordant pairs over the sum of concordant and discordant pairs, was calculated. The observed rates of concordance for Type II diabetes at 1, 5, 10, and 15 years follow-up were 17, 33, 57, and 76%, respectively. The concordance rate for any abnormality of glucose metabolism (either Type II diabetes or impaired glucose tolerance) at 15 years follow-up was 96%. The concordance rate for Type II diabetes in monozygotic twins is very high even in twins initially ascertained discordant for diabetes.

United Kingdom prospective diabetes study (UKPDS): what now or so what?

The UKPDS was a 20-year study involving 23 centres in the United Kingdom. More than 5000 patients with Type 2 diabetes were recruited. The aim of the study was to determine the impact of intensive blood glucose control on 21 predetermined clinical endpoints using, in the care of blood glucose control, sulphonylureas or insulin therapy or, in the overweight patient, treatment with metformin. In addition, the study investigated the impact of intensive blood pressure control on macro- and microvascular complications of diabetes and compared captopril treatment with atenolol. UKPDS found that improved control of blood glucose or blood pressure reduced the risk of major diabetic eye disease by one quarter, serious deterioration of vision by nearly one half, early kidney damage by one third, strokes by one third, and death from diabetes-related causes by one third. Blood glucose control had little or no effect on macrovascular events. There was no evidence of a major detrimental effect of the drugs or insulin on survival or outcome other than the expected risk of hypoglycaemia. Metformin appeared to be the drug of choice in obese diabetic patients. The targets of glucose and blood pressure control were often achieved by using several drugs. Many patients at the end of the studies were on four or five drugs for blood glucose and blood pressure treatment. The results and implications of the study are discussed. It is proposed that the results of UKPDS herald a new era of more focused therapy of Type 2 diabetes.