Baseline heterogeneity in glucose metabolism marks the risk for type 1 diabetes and complicates secondary prevention

Heterogeneity of beta-cell function in subjects with multiple islet autoantibodies in the TEDDY family prevention study - TEFA

BACKGROUND

Individuals with multiple islet autoantibodies are at increased risk for clinical type 1 diabetes and may proceed gradually from stage to stage complicating the recruitment to secondary prevention studies. We evaluated multiple islet autoantibody positive subjects before randomisation for a clinical trial 1 month apart for beta-cell function, glucose metabolism and continuous glucose monitoring (CGM). We hypothesized that the number and type of islet autoantibodies in combination with different measures of glucose metabolism including fasting glucose, HbA1c, oral glucose tolerance test (OGTT), intra venous glucose tolerance test (IvGTT) and CGM allows for more precise staging of autoimmune type 1 diabetes than the number of islet autoantibodies alone.

METHODS

Subjects (n = 57) at 2-50 years of age, positive for two or more islet autoantibodies were assessed by fasting plasma insulin, glucose, HbA1c as well as First Phase Insulin Response (FPIR) in IvGTT, followed 1 month later by OGTT, and 1 week of CGM (n = 24).

RESULTS

Autoantibodies against GAD65 (GADA; n = 52), ZnT8 (ZnT8A; n = 40), IA-2 (IA-2A; n = 38) and insulin (IAA; n = 28) were present in 9 different combinations of 2-4 autoantibodies. Fasting glucose and HbA1c did not differ between the two visits. The estimate of the linear relationship between log2-transformed FPIR as the outcome and log2-transformed area under the OGTT glucose curve (AUC) as the predictor, adjusting for age and sex was - 1.88 (- 2.71, - 1.05) p = 3.49 × 10-5. The direction of the estimates for all glucose metabolism measures was positive except for FPIR, which was negative. FPIR was associated with higher blood glucose. Both the median and the spread of the CGM glucose data were significantly associated with higher glucose values based on OGTT, higher HbA1c, and lower FPIR. There was no association between glucose metabolism, autoantibody number and type except that there was an indication that the presence of at least one of ZnT8(Q/R/W) A was associated with a lower log2-transformed FPIR (- 0.80 (- 1.58, - 0.02), p = 0.046).

CONCLUSIONS

The sole use of two or more islet autoantibodies as inclusion criterion for Stage 1 diabetes in prevention trials is unsatisfactory. Staging type 1 diabetes needs to take the heterogeneity in beta-cell function and glucose metabolism into account.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02605148 , November 16, 2015.

Beta cell function in participants with single or multiple islet autoantibodies at baseline in the TEDDY Family Prevention Study: TEFA

Aim

The aim of the present study was to assess beta cell function based on an oral glucose tolerance test (OGTT) in participants with single islet autoantibody or an intravenous glucose tolerance test (IvGTT) in participants with multiple islet autoantibodies.

Materials and methods

Healthy participants in Sweden and Finland, between 2 and 49.99 years of age previously identified as positive for a single (n = 30) autoantibody to either insulin, glutamic acid decarboxylase, islet antigen-2, zinc transporter 8 or islet cell antibodies or multiple autoantibodies (n = 46), were included. Participants positive for a single autoantibody underwent a 6-point OGTT while participants positive for multiple autoantibodies underwent an IvGTT. Glucose, insulin and C-peptide were measured from OGTT and IvGTT samples.

Results

All participants positive for a single autoantibody had a normal glucose tolerance test with 120 minutes glucose below 7.70 mmol/L and HbA1c values within the normal range (<42 mmol/mol). Insulin responses to the glucose challenge on OGTT ranged between 13.0 and 143 mIU/L after 120 minutes with C-peptide values between 0.74 and 4.60 nmol/L. In Swedish participants, the first-phase insulin response (FPIR) on IvGTT was lower in those positive for three or more autoantibodies (n = 13; median 83.0 mIU/L; range 20.0-343) compared to those with two autoantibodies (n = 15; median 146 mIU/L; range 19.0-545; P = .0330).

Conclusion

Participants positive for a single autoantibody appeared to have a normal beta cell function. Participants positive for three or more autoantibodies had a lower FPIR as compared to participants with two autoantibodies, supporting the view that their beta cell function had deteriorated.

Safety and efficacy of autoantigen-specific therapy with 2 doses of alum-formulated glutamate decarboxylase in children with multiple islet autoantibodies and risk for type 1 diabetes: A randomized clinical trial

OBJECTIVE

Treatments have failed to delay or stop the autoimmune process, preceding onset of type 1 diabetes. We investigated if autoantigen-specific treatment with alum-formulated glutamate decarboxylase (GAD-Alum) was safe and affected progression to type 1 diabetes in children with islet autoimmunity.

METHODS

In an investigator-initiated, double-blind, placebo-controlled clinical trial, non-diabetic children aged 4 to 17.9 years with autoantibodies to glutamate decarboxylase (GADA) and at least one of insulinoma-associated protein 2, insulin or zinc-transporter 8, were randomized, stratified by 2 or ≥3 islet autoantibodies, to 2 injections of 20 μg GAD-Alum or placebo, 30 days apart. Main outcome was safety, investigated by adverse events, hematology, chemistry, thyroid and celiac autoimmunity and titers of islet autoantibodies, and efficacy, investigated by cumulative incidence of diabetes onset over 5-year follow-up. Secondary variables: change in first-phase insulin release (FPIR) after intravenous glucose tolerance tests, fasting, 120 minutes and Area under the curve (AUC) C-peptide and p-glucose after oral glucose tolerance tests and HbA1c.

RESULTS

Fifty children (median age: 5.2) were assigned 1:1 to GAD-Alum or placebo, all receiving full treatment and included in the analyses. GAD-Alum did not affect any safety parameter, while GADA titers increased (P = .001). Time to clinical diagnosis was not affected by treatment (hazard ratio, HR = 0.77, P = .574) in the full population or in the separate stratum groups. Treatment did not affect any of the secondary variables.

CONCLUSIONS

GAD-Alum as a subcutaneous prime and boost injection was safe in prediabetic young children but did not affect progression to type 1 diabetes. The safety of GAD-Alum should prove useful in future prevention studies.

Characteristics of the pre-diabetic period in children with high risk of type 1 diabetes recruited from the general Swedish population-The ABIS study

BACKGROUND

There is a need for increased understanding of the pre-diabetic period in individuals with high risk of type 1 diabetes from the general population.

METHODS

High-risk children (n = 21) positive for multiple islet autoantibodies were identified by autoantibody screening within the All Babies in Southeast Sweden study. The children and their parents were enrolled in a 2-year prospective follow-up study aiming to characterize the pre-diabetic period. Blood samples were collected every 6 months for measurement of C-peptide, HbA1c, fasting glucose, and autoantibodies. Human leukocyte antigen-genotype was determined, and oral glucose tolerance test was performed every 12 months.

RESULTS

Despite positivity for multiple autoantibodies, 9 out of 21 individuals had low-risk human leukocyte antigen-genotypes. Children who progressed to manifest diabetes (progressors, n = 12) had higher levels of IA2A and ZnT8A than children who did not (non-progressors, n = 9). Impaired glucose tolerance and impaired fasting glucose was observed to the same extent in progressors and non-progressors, but HbA1c increased over time in progressors in spite of increased C-peptide.

CONCLUSIONS

Autoantibodies to IA2 and ZnT8 may be useful discriminators for disease progression in at-risk children from the general population. Dysglycemia was observed long before diagnosis, and difficulties in maintaining glucose homeostasis despite increased C-peptide indicate that insulin resistance might be an important accelerator of disease in risk individuals.

A Swedish approach to the prevention of type 1 diabetes

BACKGROUND

The autoimmune destruction of beta cells, resulting in clinical type 1 diabetes, may start early in life and last for several months or years. During this period of time, we have an opportunity to try to prevent or delay further beta-cell destruction and clinical onset of type 1 diabetes.

OBJECTIVES

Ongoing prediction and prevention studies in Skåne, Sweden are described.

METHODS

During September 2000 to August 2004, 35 000 children were screened at birth for genetic type 1 diabetes risk in the Diabetes Prediction in Skåne Study (DiPiS). In August 2004, the screening continued within the Enviromnental Determinants of Diabetes in the Young study (TEDDY). In the clinical trial Diabetes Prevention - Immune Tolerance (DiAPREV-IT), children with multiple islet autoimmunity have been included to investigate if immune tolerance with Alum-formulated GAD65 may prevent further beta-cell loss.

RESULTS

In DiPiS and TEDDY, a large number of children are followed in order to find the factors that trigger the autoimmune process leading to type 1 diabetes. Children followed in the studies develop diabetes at an early stage of disease, with few symptoms and a low frequency of diabetes ketoacidosis. DiAPREV-IT is still blinded and results will be available in December 2016.

CONCLUSION

Large prospective studies will be needed to understand the complex process leading to type 1 diabetes. Secondary prevention may be possible in children with islet autoimmunity, but the studies are complicated by the variability of glucose metabolism and beta-cell loss.

Prediction and prevention of type 1 diabetes: update on success of prediction and struggles at prevention

Type 1 diabetes mellitus (T1DM) is the archetypal example of a T cell-mediated autoimmune disease characterized by selective destruction of pancreatic β cells. The pathogenic equation for T1DM presents a complex interrelation of genetic and environmental factors, most of which have yet to be identified. On the basis of observed familial aggregation of T1DM, it is certain that there is a decided heritable genetic susceptibility for developing T1DM. The well-known association of T1DM with certain human histocompatibility leukocyte antigen (HLA) alleles of the major histocompatibility complex (MHC) was a major step toward understanding the role of inheritance in T1DM. Type 1 diabetes is a polygenic disease with a small number of genes having large effects (e.g., HLA) and a large number of genes having small effects. Risk of T1DM progression is conferred by specific HLA DR/DQ alleles [e.g., DRB1*03-DQB1*0201 (DR3/DQ2) or DRB1*04-DQB1*0302 (DR4/DQ8)]. In addition, the HLA allele DQB1*0602 is associated with dominant protection from T1DM in multiple populations. A concordance rate lower than 100% between monozygotic twins indicates a potential involvement of environmental factors on disease development. The detection of at least two islet autoantibodies in the blood is virtually pre-diagnostic for T1DM. The majority of children who carry these biomarkers, regardless of whether they have an a priori family history of the disease, will develop insulin-requiring diabetes. Facilitating pre-diagnosis is the timing of seroconversion which is most pronounced in the first 2 yr of life. Unfortunately the significant progress in improving prediction of T1DM has not yet been paralleled by safe and efficacious intervention strategies aimed at preventing the disease. Herein we summarize the chequered history of prediction and prevention of T1DM, describing successes and failures alike, and thereafter examine future trends in the exciting, partially explored field of T1DM prevention.