Physical activity is associated with lower insulin and C-peptide during glucose challenge in children and adolescents with family background of diabetes

AIMS

Children and adolescents with a family history of diabetes are at increased risk of overweight, but little is known about the potentially beneficial effects of physical activity on these children. The objective of this study was to investigate the association between moderate to vigorous physical activity (MVPA) and metabolic and inflammatory risks in children and adolescents with a family background of Type 1 diabetes or gestational diabetes.

METHODS

Valid MVPA measurements, made with accelerometers, were available from 234 participants (median age, 10.2 years) who had a first-degree relative with either Type 1 or gestational diabetes. Anthropometric and metabolic measurements were made and cytokines measured, and were correlated with MVPA measurements, with stepwise adjustment for confounding factors, in a cross-sectional analysis.

RESULTS

MVPA was negatively associated with insulin and C-peptide during challenge with an oral glucose tolerance test. MVPA was also significantly positively associated with the insulin sensitivity index, whereas no consistently significant associations were found between MVPA and BMI, blood pressure or cytokine levels.

DISCUSSION

Our findings indicate that physical activity may have beneficial effects on insulin and C-peptide metabolism in children and adolescents with a family background of diabetes, but show no evidence of a protective association with other health-related outcomes.

Development of a simple tool to predict the risk of postpartum diabetes in women with gestational diabetes mellitus

AIMS

Women with gestational diabetes mellitus (GDM) have an increased risk of diabetes postpartum. We developed a score to predict the long-term risk of postpartum diabetes using clinical and anamnestic variables recorded during or shortly after delivery.

METHODS

Data from 257 GDM women who were prospectively followed for diabetes outcome over 20 years of follow-up were used to develop and validate the risk score. Participants were divided into training and test sets. The risk score was calculated using Lasso Cox regression and divided into four risk categories, and its prediction performance was assessed in the test set.

RESULTS

Postpartum diabetes developed in 110 women. The computed training set risk score of 5 × body mass index in early pregnancy (per kg/m(2)) + 132 if GDM was treated with insulin (otherwise 0) + 44 if the woman had a family history of diabetes (otherwise 0) - 35 if the woman lactated (otherwise 0) had R (2) values of 0.23, 0.25, and 0.33 at 5, 10, and 15 years postpartum, respectively, and a C-Index of 0.75. Application of the risk score in the test set resulted in observed risk of postpartum diabetes at 5 years of 11 % for low risk scores ≤140, 29 % for scores 141-220, 64 % for scores 221-300, and 80 % for scores >300.

CONCLUSIONS

The derived risk score is easy to calculate, allows accurate prediction of GDM-related postpartum diabetes, and may thus be a useful prediction tool for clinicians and general practitioners.

Risk Stratification in Women with Gestational Diabetes According to and Beyond Current WHO Criteria

The pregnancy outcomes in women with gestational diabetes mellitus (GDM) and 'overt diabetes in pregnancy' were compared and the need for further subclassification was investigated with respect to postpartum outcome risk. Data from 944 women who had been uniformly diagnosed as having GDM in Munich, Germany, between 1998 and 2010, were re-classified into GDM and 'overt diabetes in pregnancy'. Pregnancy related outcomes in the offspring were derived from Bavarian birth registry data. Classification and regression trees were used to identify further GDM sub-phenotypes. In total, 88 women (9.3%) were re-classified as having 'overt diabetes in pregnancy'. Compared to women with GDM, women with 'overt diabetes in pregnancy' used insulin more frequently, and were at increased risk for large for gestational age infants [odds ratio 2.50 (95% confidence interval 1.02, 6.13)], preterm delivery [odds ratio 3.28 (1.02, 10.50)], and low APGAR-score at 5 min [odds ratio 12.70 (1.58, 102.2)]. In the 856 women with GDM, classification and regression tree analyses provided further risk stratification in that a combination of fasting glucose>5.3 mmol/l and 1-h glucose>11.1 mmol/l at GDM diagnosis predicted insulin requirement [OR 5.57 (3.75, 8.27) compared to the rest], and maternal body mass index (BMI)≥35 kg/m(2) predicted large for gestational age status. The new differentiation between GDM and 'overt diabetes in pregnancy' is a first step towards refining classification relevant to fetal and maternal postpartum risk. A combination of glucose levels and maternal BMI at diagnosis of GDM may provide further improvement.

IGRP and insulin vaccination induce CD8+ T cell-mediated autoimmune diabetes in the RIP-CD80GP mouse

Autoimmune diabetes is characterized by autoantigen-specific T cell-mediated destruction of pancreatic islet beta cells, and CD8(+) T cells are key players during this process. We assessed whether the bitransgenic RIP-CD80 x RIP-LCMV-GP (RIP-CD80GP) mice may be a versatile antigen-specific model of inducible CD8(+) T cell-mediated autoimmune diabetes. Antigen-encoding DNA, peptide-loaded dendritic cells and antigen plus incomplete Freund's adjuvant were used for vaccination. Of 14 pancreatic proteins tested by DNA vaccination, murine pre-proinsulin 2 (100% of mice; median time after vaccination, 60 days) and islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) (77%, 58 days) could induce diabetes. Vaccination with DNA encoding for zinc transporter 8, Ia-2, Ia-2β, glutamic acid decarboxylase 67 (Gad67), chromogranin A, insulinoma amyloid polypeptide and homeobox protein Nkx-2.2 induced diabetes development in 25-33% of mice. Vaccination with DNA encoding for Gad65, secretogranin 5, pancreas/duodenum homeobox protein 1 (Pdx1), carboxyl ester lipase, glucagon and control hepatitis B surface antigen (HBsAg) induced diabetes in <20% of mice. Diabetes induction efficiency could be increased by DNA vaccination with a vector encoding a ubiquitin-antigen fusion construct. Diabetic mice had florid T cell islet infiltration. CD8(+) T cell targets of IGRP were identified with a peptide library-based enzyme-linked immunospot assay, and diabetes could also be induced by vaccination with major histocompatibility complex (MHC) class I-restricted IGRP peptides loaded on mature dendritic cells. Vaccination with antigen plus incomplete Freund's adjuvant, which can prevent diabetes in other models, led to rapid diabetes development in the RIP-CD80GP mouse. We conclude that RIP-CD80GP mice are a versatile model of antigen specific autoimmune diabetes and may complement existing mouse models of autoimmune diabetes for evaluating CD8(+) T cell-targeted prevention strategies.

Characteristics of rapid vs slow progression to type 1 diabetes in multiple islet autoantibody-positive children

AIMS/HYPOTHESIS

Islet autoantibody-positive children progress to type 1 diabetes at variable rates. In our study, we asked whether characteristic autoantibody and/or gene profiles could be defined for phenotypes showing extreme progression.

METHODS

Autoantibodies to insulin (IAA), GAD (GADA), insulinoma-associated antigen-2 (IA-2A) and zinc transporter 8 (ZnT8A) were measured in follow-up sera, and genotyping for type 1 diabetes susceptibility genes (HLA-DR/HLA-DQ, INS variable number of tandem repeats [VNTR] and single nucleotide polymorphisms at PTPN22, PTPN2, ERBB3, IL2, SH2B3, CTLA4, IFIH1, KIAA0350 [also known as CLEC16A], CD25, IL18RAP, IL10, COBL) was performed on the DNA samples of children born to a parent with type 1 diabetes and prospectively followed from birth for up to 22 years.

RESULTS

Of the 1,650 children followed, 23 developed multiple autoantibodies and progressed to diabetes within 3 years (rapid progressors), while 24 children developed multiple autoantibodies and remained non-diabetic for more than 10 years from seroconversion (slow progressors). Rapid and slow progressors were similar with respect to HLA-DR/HLA-DQ genotypes, development of IAA, GADA and ZnT8A, and progression to multiple autoantibodies. In contrast, IA-2A development was considerably delayed in the slow progressors. Furthermore, both groups were effectively distinguished by the combined presence or absence of type 1 diabetes susceptibility alleles of non-HLA genes, most notably IL2, CD25, INS VNTR, IL18RAP, IL10, IFIH1 and PTPN22, and discrimination was improved among children carrying high-risk HLA-DR/HLA-DQ genotypes.

CONCLUSIONS/INTERPRETATION

Our data suggest that genotypes of non-HLA type 1 diabetes susceptibility genes influence the likelihood or rate of diabetes progression among children with multiple islet autoantibodies.

Reduced blood leukocyte and neutrophil numbers in the pathogenesis of type 1 diabetes

Very little is known about the role of the innate immune system in the course of human type 1 diabetes. Here we investigated neutrophil numbers along with other leukocyte populations in patients at diagnosis of type 1 diabetes and during prediabetes. Complete and differential blood counts were analyzed from 107 adult patients with newly diagnosed type 1 diabetes, 21 children with persistent islet autoantibodies and a family history of type 1 diabetes, and 1 238 age and gender matched control subjects, all individuals without any signs of acute infection.Adult patients with newly diagnosed type 1 diabetes had significantly lower total WBC (p<1×10⁻⁶), neutrophil (p<1×10⁻⁶), basophil (p<1×10⁻⁶), monocyte (p=4×10⁻⁶) and lymphocyte (p<1×10⁻⁶) counts compared to control subjects. Erythrocyte, eosinophil and platelet counts did not differ between groups. Similarly, children with persistent islet autoantibodies had decreased WBC (p=0.001), neutrophils (p=0.003), and lymphocytes (p=0.006) in comparison to control children. Our findings demonstrate a perturbation of leukocyte homeostasis at and prior to onset of type 1 diabetes suggesting a general involvement of the innate immune system in the pathogenesis of type 1 diabetes.

A strategy for combining minor genetic susceptibility genes to improve prediction of disease in type 1 diabetes

Genome-wide association studies have identified gene regions associated with type 1 diabetes. The aim of this study was to determine how the combined allele frequency of multiple susceptibility genes can stratify islet autoimmunity and/or type 1 diabetes risk. Children of parents with type 1 diabetes and prospectively followed from birth for the development of islet autoantibodies and diabetes were genotyped for single-nucleotide polymorphisms at 12 type 1 diabetes susceptibility genes (ERBB3, PTPN2, IFIH1, PTPN22, KIAA0350, CD25, CTLA4, SH2B3, IL2, IL18RAP, IL10 and COBL). Non-human leukocyte antigen (HLA) risk score was defined by the total number of risk alleles at these genes. Receiver operator curve analysis showed that the non-HLA gene combinations were highly effective in discriminating diabetes and most effective in children with a high-risk HLA genotype. The greatest diabetes discrimination was obtained by the sum of risk alleles for eight genes (IFIH1, CTLA4, PTPN22, IL18RAP, SH2B3, KIAA0350, COBL and ERBB3) in the HLA-risk children. Non-HLA-risk allele scores stratified risk for developing islet autoantibodies and diabetes, and progression from islet autoimmunity to diabetes. Genotyping at multiple susceptibility loci in children from affected families can identify neonates with sufficient genetic risk of type 1 diabetes to be considered for early intervention.

Age-related islet autoantibody incidence in offspring of patients with type 1 diabetes

AIMS/HYPOTHESIS

Seroconversion to islet autoantibodies precedes type 1 diabetes. This study aimed to identify periods of high seroconversion incidence, which could be targeted for mechanistic and therapeutic studies.

METHODS

Incidence of islet autoantibodies was calculated in 1,650 genetically at-risk children followed with measurements of islet autoantibodies and thyroid autoantibodies at age 9 months and 2, 5, 8, 11, 14 and 17 years. Peak incidence periods were confirmed in a second cohort of 150 children followed until age 6 years with three-monthly samples up to age 3 years.

RESULTS

Islet autoantibody incidence (per 1,000 person-years) was 18.5 until age 9 months, 21 from 9 months to 2 years and <10 for intervals after age 2 years. The second cohort confirmed peak incidence around age 9 months and demonstrated an absence of seroconversion before this age. Seroconversion to insulin autoantibodies occurred earlier than other autoantibodies (p<0.01 against glutamic acid decarboxylase [GAD]-, insulinoma-associated protein 2 [IA-2]- and zinc transporter 8 [ZnT8]-autoantibodies). Early peak seroconversion incidence was most evident in children with high-risk HLA DR3/4-DQ8 or DR4/4-DQ8 genotypes.

CONCLUSION

The age period 9 months to 2 years is associated with a high incidence of activation of type 1 diabetes associated autoimmunity in genetically at-risk children and should be targeted for effective primary prevention strategies.