Inverse relationship between GAD65 antibody levels and severe retinopathy in younger type 1 diabetic patients

The Relationship of Serum Diabetes Antibodies With the Development of Early Diabetic Retinopathy Findings in Children With Type 1 Diabetes Mellitus

PURPOSE

To explore how serum diabetes autoantibodies are related to the development of early diabetic retinopathy in children with type 1 diabetes mellitus.

METHODS

In this prospective and observational study, 62 patients with type 1 diabetes mellitus who had not yet developed clinical diabetic retinopathy were followed up for at least 5 years. Healthy volunteers aged 10 to 20 years were also included. Insulin, pancreatic islet cells, and glutamic acid decarboxylase (GAD) autoantibodies were measured with an RIA kit at the time of type 1 diabetes mellitus diagnosis. Optical coherence tomography angiography (OCTA) was used to evaluate the foveal avascular zone (FAZ) and parafoveal vascular density (PVD) for the development of early diabetic retinopathy among the groups. Patients' OCTA findings were compared with those of healthy volunteers. The obtained data were analyzed via IBM SPSS Statistics for Windows, version 27.0. Spearman's rank correlation test and regression analysis were performed to determine independent predictors of OCTA and type 1 diabetes mellitus parameters.

RESULTS

Eighteen boys and 44 girls with type 1 diabetes mellitus with a median age of 15.6 years (range: 10.08 to 20.88 years) were evaluated. Healthy control participants with a median age of 15.3 years (range: 14.2 to 18.2 years) were also included. The mean FAZ was greater in the type 1 diabetes mellitus group than in the healthy control group (P = .013 and .119, respectively). The mean PVD was significantly lower in the type 1 diabetes mellitus group than in the healthy control group. There was no significant correlation between serum diabetes autoantibodies (GAD and insulin autoantibodies) and FAZ or PVD (FAZ and GAD; r = 0.138, P = .286, FAZ and anti-insulin; r = 0.100, P = .441, PVD and GAD; r = -0.151, P = .24, PVD and anti-insulin; r = -0.087, P = .499).

CONCLUSIONS

Type 1 diabetes mellitus in children without clinically detectable diabetic retinopathy is associated with impaired retinal microcirculation and irregularities at the FAZ margin. Impaired retinal microcirculation and irregularities were associated with glycated hemoglobin levels in the study group. Thus, studies with larger patient series are needed. [J Pediatr Ophthalmol Strabismus. 2025;62(2):135-142.].

The association of islet autoantibodies with the neural retinal thickness and microcirculation in type 1 diabetes mellitus with no clinical evidence of diabetic retinopathy

OBJECTIVE

To examine the association between islet autoantibodies (IAbs) and the retinal neurovascular changes in type 1 diabetes mellitus (T1DM) with no diabetic retinopathy (NDR).

METHODS

This cross-sectional study measured the neural retinal structure and microvascular density of 118 NDR eyes using spectral-domain optical coherence tomography angiography. Retinal structure parameters included retinal thickness (RT), inner retinal thickness (iRT), retina never fibral layer thickness (RNFL thickness), ganglion cell complex thickness (GCC thickness), and loss volume of GCC. Microvascular parameters included vessel density of superficial capillary plexus (sVD), vessel density of deep capillary plexus, and vessel density of choroid capillary plexus. Comparison and correlation analyses of these OCTA parameters were made with various IAbs, including glutamic acid decarboxylase antibody (GADA), tyrosine phosphatase-related islet antigen 2 antibody (IA2A), and zinc transporter 8 antibody (ZnT8A). A general linear model was used to understand the association of IAbs with the retina parameters.

RESULTS

The IAb positive (IAbs +) group, which included 85 patients, had thinner RT (235.20 ± 18.10 mm vs. 244.40 ± 19.90 mm at fovea, P = 0.021) and thinner iRT (120.10 ± 9.00 mm vs. 124.70 ± 6.90 mm at parafovea, P = 0.015), compared with the IAb negative (IAbs-) group comprising 33 patients. Furthermore, a more severe reduction of RT was demonstrated in the presence of multiple IAbs. Among the three IAbs, GADA was the most significant independent risk factor of all-round RT decrease (β = -0.20 vs. -0.27 at fovea and parafovea, respectively, P < 0.05), while titers of IA2A negatively affect sVD in the parafovea (β = -0.316, P = 0.003).

CONCLUSIONS

IAbs are associated with neural retinal thinning and microcirculation reduction in T1DM patients before the clinical onset of diabetic retinopathy.

Nox (NADPH Oxidase) 1, Nox4, and Nox5 Promote Vascular Permeability and Neovascularization in Retinopathy

Hypertension is a risk factor for the vascular permeability and neovascularization that threatens vision in diabetic retinopathy. Excess reactive oxygen species derived from the Nox (NADPH oxidase) isoforms, Nox1 and Nox4, contributes to vasculopathy in diabetic retinopathy; however, if Nox1/4 inhibition is beneficial in hypertensive diabetic retinopathy is unknown. Here, we determined that diabetic spontaneously hypertensive rats had exacerbated retinal vascular permeability and expression of angiogenic and inflammatory factors, compared with normotensive diabetic Wistar Kyoto rats. GKT136901, a specific dual inhibitor of Nox1 and Nox4, prevented these events in diabetic Wistar Kyoto rats and spontaneously hypertensive rats. Retinal neovascularization does not develop in diabetic rodents, and therefore, the oxygen-induced retinopathy model is used to evaluate this pathology. We previously demonstrated that Nox1/4 inhibition reduced retinal neovascularization in oxygen-induced retinopathy. However, although Nox5 is expressed in human retina, its contribution to retinopathy has not been studied in vivo, largely due to its absence from the rodent genome. We generated transgenic mice with inducible human Nox5 expressed in endothelial cells (vascular endothelial-cadherin⁺Nox5⁺ mice). In vascular endothelial-cadherin⁺Nox5⁺ mice with oxygen-induced retinopathy, retinal vascular permeability and neovascularization, as well as the expression of angiogenic and inflammatory factors, were increased compared with wild-type littermates. In bovine retinal endothelial cells, which express Nox1, Nox4, and Nox5, Nox1/4 inhibition, as well as Nox5 silencing RNA, reduced the high glucose-induced upregulation of oxidative stress, angiogenic, and inflammatory factors. Collectively, these data indicate the potential of Nox1, Nox4, and Nox5 inhibition to reduce vision-threatening damage to the retinal vasculature.

The course of diabetes in children, adolescents and young adults: does the autoimmunity status matter?

BACKGROUND

Initial classification of diabetes of young may require revision to improve diagnostic accuracy of different forms of diabetes. The aim of our study was to examine markers of beta-cell autoimmunity in a cohort of young (0-25 years) patients with type 1 diabetes and compare the presentation and course of the disease according to the presence of pancreatic antibodies.

METHODS

Cross-sectional population-based study was performed covering 100% of pediatric (n = 860) and 70% of 18-25 years old adult patients (n = 349) with type 1 diabetes in Lithuania.

RESULTS

No antibodies (GAD65, IA-2, IAA and ICA) were found in 87 (7.5%) cases. Familial history of diabetes was more frequent in those with antibodies-negative diabetes (24.1 vs. 9.4%, p < 0.001). Gestational age, birth weight and age at diagnosis was similar in both groups. Ketosis at presentation was more frequent in patients with autoimmune diabetes (88.1 vs. 73.5%, p < 0.05). HbA1c at the moment of investigation was 8.6 (3) vs. 8.7 (2.2)% in antibodies-negative and antibodies-positive diabetes groups, respectively, p > 0.05. In the whole cohort, neuropathy was found in 8.8% and nephropathy - in 8.1% of cases, not depending on autoimmunity status. Adjusted for age at onset, disease duration and HbA1c, retinopathy was more frequent in antibodies-negative subjects (13.8 vs. 7.8%, p < 0.05).

CONCLUSION

Antibodies-negative pediatric and young adult patients with type 1 diabetes in this study had higher incidence of family history of diabetes, higher frequency of retinopathy, less frequent ketosis at presentation, but similar age at onset, HbA1c, incidence of nephropathy and neuropathy compared to antibodies-positive patients.

Predictors of microvascular complications in type 1 diabetic patients at onset: the role of metabolic memory

BACKGROUND

Several epidemiological studies showed a close association between metabolic control and microvascular complications in type 1 Diabetes Mellitus (T1DM). The aim of our longitudinal observational study was to evaluate the predictive role of the main clinical and biochemical parameters in determining microvascular complications.

METHODS

376 T1DM patients, hospitalized in our division from 1991 to 2005 (mean follow-up=10.93±4.26 years) were studied. Stepwise Cox regression analysis was used to identify the influence of residual ß-cell function, ß-cell autoimmunity, HbA1c levels and other clinical and laboratory parameters in the development of microalbuminuria and retinopathy.

RESULTS

The probability of developing microalbuminuria was higher in males than in females (HR 1.82; 95% CI 1.01-3.28; p=0.044), in patients with higher mean HbA1c values (HR 2.80; 95% CI 1.63-4.83; p<0.001), longer duration of disease (HR 1.98; 95% CI 1.10-3.57; p=0.022) and younger age of diabetes onset (HR 0.53; 95% CI 0.03-0.92; p=0.026). An increased probability of developing retinopathy was found in patients with higher mean HbA1c levels during follow-up (HR 2.35; 95% CI 1.34-4.12, p=0.003), as well as at onset (HR 1.85; 95% CI 1.06-3.24; p=0.030).

CONCLUSIONS

Our study suggests that among the clinical, metabolic, immunological and biochemical factors evaluated at onset, only HbA1c is predictive for the microangiopathy development in T1DM.

HLA genes, islet autoantibodies and residual C-peptide at the clinical onset of type 1 diabetes mellitus and the risk of retinopathy 15 years later

Aims/Hypothesis

HLA genes, islet autoantibodies and residual C-peptide were studied to determine the independent association of each exposure with diabetic retinopathy (DR), 15 years after the clinical onset of type 1 diabetes in 15–34 year old individuals.

Methods

The cohort was identified in 1992 and 1993 by the Diabetes Incidence Study in Sweden (DISS), which investigates incident cases of diabetes for patients between 15 and 34 years of age. Blood samples at diagnosis were analyzed to determine HLA genotype, islet autoantibodies and serum C-peptide. In 2009, fundus photographs were obtained from patient records. Study measures were supplemented with data from the Swedish National Diabetes Registry.

Results

The prevalence of DR was 60.2% (148/246). Autoantibodies against the 65 kD isoform of glutamate decarboxylase (GADA) at the onset of clinical diabetes increased the risk of DR 15 years later, relative risk 1.12 for each 100 WHO units/ml, [95% CI 1.02 to 1.23]. This equates to risk estimates of 1.27, [95% CI 1.04 to 1.62] and 1.43, [95% CI 1.06 to 1.94] for participants in the highest 25^th (GADA>233 WHO units/ml) and 5^th percentile (GADA>319 WHO units/ml) of GADA, respectively. These were adjusted for duration of diabetes, HbA_1c, treated hypertension, sex, age at diagnosis, HLA and C-peptide. Islet cell autoantibodies, insulinoma-antigen 2 autoantibodies, residual C-peptide and the type 1 diabetes associated haplotypes DQ2, DQ8 and DQ6 were not associated with DR.

Conclusions

Increased levels of GADA at the onset of type 1 diabetes were associated with DR 15 years later. These results, if confirmed, could provide additional insights into the pathogenesis of the most common microvascular complication of diabetes and lead to better risk stratification for both patient screenings and DR treatment trials.

Islet cell autoantibody levels after the diagnosis of young adult diabetic patients

AIMS

The aim was to determine the course of islet cell antibodies [glutamate decarboxylase (GADA), tyrosine phosphatase-like islet antigen 2 (IA-2A) and islet cell (ICA)] after the diagnosis of the diabetic patient.

METHODS

The Diabetes Incidence Study in Sweden (DISS) attempted to prospectively enrol all newly diagnosed diabetic patients aged 15-34 years during 1992 and 1993. C-peptide and autoantibody levels were determined from venous blood samples at diagnosis and again at yearly intervals for 6 years.

RESULTS

After the first year, the odds of remaining GADA positive decreased by 9% per year [odds ratio (OR) = 0.91, 95% confidence interval (CI) = 0.85-0.96] while the mean GADA index remained unchanged ( = 0.8, P = 0.37). There was no change in the percentage of subjects testing IA-2A positive after the first year ( = 0.1, P = 0.75). However, the mean index decreased 0.04 per year (95% CI: 0.03-0.05)-a 7.9% decline (95% CI: 5.4-10.4%). The odds of a subject testing positive for ICA decreased by 24% per year (OR = 0.76, 95% CI = 0.70-0.82). The mean ICA levels decreased 0.75 per year (95% CI: 0.66-0.84)-a 16.4% decline (95% CI: 14.1-18.6%). The rate of change in titres for all three autoantibodies was independent of gender, human leucocyte antigen genotype and C-peptide status.

CONCLUSIONS

GADA levels remained high while ICA levels declined. In contrast to a previous study, we found that the proportion of IA-2A subjects remaining positive did not decrease after the first year, while the average index decreased slightly.

Glutamic Acid Decarboxylase Autoantibody Prevalence and Association with HLA Genotype in Patients with Younger-Onset Type 1 Diabetes and Proliferative Diabetic Retinopathy

OBJECTIVE

To investigate the relationship of HLA status and autoantibodies to glutamic acid decarboxylase (GAD) in proliferative diabetic retinopathy (PDR) to assess the role of autoimmunity and genetic markers in retinopathy.

DESIGN

Retrospective, nonrandomized, comparative study.

PARTICIPANTS

Patients who had suffered from type 1 diabetes for >10 years and who had been first diagnosed as diabetic under 30 years of age were studied. They were classified into 3 groups: 20 patients with diabetes and PDR (PDR group), 22 patients who had diabetes and severe nonproliferative diabetic retinopathy (SNPDR group), and 25 patients who had diabetes with no diabetic retinopathy (non-DR group).

METHODS

Blood was collected, and the relationship between HLA status and GAD autoantibody positivity in diabetic retinopathy was investigated in a cross-sectional study.

MAIN OUTCOME MEASURES

Human leukocyte antigen status and GAD autoantibody positivity.

RESULTS

The highest positive rate of GAD autoantibody was 56.0% in the non-DR group, followed by the SNPDR group (40.1%) and the PDR group (15.0%). The frequencies of the HLA-DQ4 and -DR4/-DQ4 haplotypes were significantly higher in the PDR group (75.0% and 65%, respectively) than in the SNPDR group (40.9% and 31.8%) or the non-DR group (40.0% and 28.0%) (P = 0.035 and P = 0.026, respectively). The prevalence of GAD antibodies was lower in patients with the HLA-DR4 and HLA-DQ4 alleles and -DR4/-DQ4 haplotype frequencies in the PDR group (P = 0.018, P = 0.0088, and P = 0.0031, respectively).

CONCLUSIONS

We found that the existence of GAD antibodies is inversely related and HLA status is directly related to the stage or severity of retinopathy.

The role of autoimmunity at diagnosis of type 1 diabetes in the development of thyroid and celiac disease and microvascular complications

OBJECTIVE

The purpose of this study was to explore whether the presence of thyroid and endomysial autoantibodies at diagnosis of type 1 diabetes in children predicts development of thyroid and celiac disease, respectively, and whether diabetes-associated autoantibodies at diagnosis predict development of microvascular complications up to 13 years later.

RESEARCH DESIGN AND METHODS

Autoantibodies were measured at diagnosis of type 1 diabetes in 173 children aged 0-15 years and included thyroperoxidase antibody (TPOA), endomysial antibody (EMA), islet cell autoantibody, GAD antibody (GADA), and insulin autoantibody. Thyroid disease was defined as thyroid stimulating hormone level > or = 5 microU/ml. Celiac disease was confirmed by small-bowel biopsy. Assessment of microvascular complications included stereoscopic fundal photography, pupillometry, thermal threshold, and albumin excretion rate (AER).

RESULTS

The incidence rates for thyroid and celiac disease were 0.9 and 0.7 per 100 patient-years, respectively. Within 13 years, 6 of 13 children with positive TPOA tests at diagnosis developed thyroid disease compared with 5 of 139 children with negative TPOA tests (P < 0.001). All four patients with positive EMA titers at diagnosis had biopsy-proven celiac disease. Five of 11 patients who developed thyroid disease and 4 of 8 who developed celiac disease had negative TPOA and EMA tests at diagnosis, respectively. Retinopathy was detected in 39% and elevated AER in 36%. The presence of diabetes-associated autoantibodies at diagnosis did not predict microvascular complications though GADA titer levels predicted pupillary abnormality.

CONCLUSIONS

Elevated TPOA and EMA levels at diagnosis of type 1 diabetes predict the development of thyroid and celiac disease, respectively. In children with negative antibody titers at diagnosis, screening at 2-year intervals is recommended.

Genetic and perinatal factors as risk for childhood type 1 diabetes

The mechanisms by which gestational infections, blood incompatibility, birth weight, mother's age and other prenatal or neonatal events increase the risk for type 1 diabetes are not understood. Studies so far have been retrospective, and there is a lack of population-based prospective studies. The possibility of identifying children at type 1 diabetes risk among first-degree relatives has resulted in prospective studies aimed at identifying postnatal events associated with the appearance of autoantibody markers for type 1 diabetes and a possible later onset of diabetes. However, the majority (85%) of new onset type 1 diabetes children do not have a first-degree relative with the disease. Population-based studies are therefore designed to prospectively analyse pregnant mothers and their offspring. One such study is DiPiS (Diabetes Prediction in Skåne), which is examining a total of about 10,000 pregnancies expected every year in the Skåne (Scania) region of Sweden that has 1.1 million inhabitants. Blood samples from all mothers in this region are obtained during pregnancy and at the time of delivery. Cord blood is analysed for HLA high-risk alleles and for autoantibodies against the 65 kD isoform of glutamic acid decarboxylase (GADA), the protein tyrosine phosphatase-related IA-2 antigen (IA-2A) and insulin (IAA) as a measure of prenatal autoimmune exposure. Identifying high-risk children by genetic, autoimmune and gestational risk factors followed by prospective analyses will make it possible to test the hypothesis that gestational events may trigger beta cell autoimmunity as a prerequisite for childhood type 1 diabetes.

Development and progression of diabetic retinopathy in patients with Type 1 diabetes who are positive for GAD autoantibody

AIMS

To investigate the relationship between autoantibodies to glutamic acid decarboxylase (GAD) and proliferative diabetic retinopathy (PDR) to assess the role of autoimmunity in retinopathy.

METHODS

Patients with Type 1 diabetes for more than 10 years who had been diagnosed under age 30 (13-28 years) were studied. They were classified into three groups. The PDR group consisted of 22 patients, the pre-PDR group was 26 patients, while the non-DR group was 32 patients who had Type 1 diabetes without retinopathy. Blood was collected to measure autoantibodies to GAD, and the relationship between PDR and GAD positivity was investigated in a cross-sectional study.

RESULTS

The highest positivity rate of GAD autoantibodies was 50.0% in the non-DR group, followed by the pre-PDR group (30.8%) and the PDR group (18.2%).

CONCLUSIONS

Production or existence of GAD autoantibodies may contribute to the prevention of retinopathy.

Type 1 Diabetes

Type 1 (insulin-dependent) diabetes occurs worldwide and can appear at any age. The genetic susceptibility is strongly associated with HLA-DQ and DR on chromosome 6, but genetic factors on other chromosomes such as the insulin gene on chromosome 11 and the cytotoxic T-lymphocyte antigen gene on chromosome 2 may modulate disease risk. Numerous studies further support the view that environmental factors are important. Gestational infections may contribute to initiation, whereas later infections may accelerate islet β-cell autoimmunity. The pathogenesis is strongly related to autoimmunity against the islet β cells. Markers of autoimmunity include autoantibodies against glutamic acid decarboxylase, insulin, and islet cell antigen-2, a tyrosine phosphatase-like protein. Molecular techniques are used to establish reproducible and precise autoantibody assays, which have been subject to worldwide standardization. The diagnostic sensitivity (40–80%) and specificity (99%) of all three autoantibodies for type 1 diabetes are high, and double or triple positivity among first-degree relatives predicts disease. Combined genetic and antibody testing improved prediction in the general population despite the transient nature of these autoantibodies. Classification of diabetes has also been improved by autoantibody testing and may be used in type 2 diabetes to predict secondary failure and insulin requirement. Islet autoantibodies do not seem to be related to late complications but rather to metabolic control, perhaps because the presence of islet cell autoantibodies marks different residual β-cell function. Combined genetic and autoantibody screening permit rational approaches to identify subjects for secondary and tertiary intervention trials.