The influence of body mass index and age on C-peptide at the diagnosis of type 1 diabetes in children who participated in the diabetes prevention trial-type 1

BACKGROUND/OBJECTIVE: The extent of influence of BMI and age on C-peptide at the diagnosis of type 1 diabetes (T1D) is unknown. We thus studied the impact of body mass index Z-scores (BMIZ) and age on C-peptide measures at and soon after the diagnosis of T1D. METHODS: Data from Diabetes Prevention Trial-Type 1 (DPT-1) participants <18.0 years at diagnosis was analyzed. Analyses examined associations of C-peptide measures with BMIZ and age in 2 cohorts: oral glucose tolerance tests (OGTTs) at diagnosis (n = 99) and mixed meal tolerance tests (MMTTs) <6 months after diagnosis (n = 80). Multivariable linear regression was utilized. RESULTS: Fasting and area under the curve (AUC) C-peptide from OGTTs (n = 99) at diagnosis and MMTTs (n = 80) after diagnosis were positively associated with BMIZ and age (P < .001 for all). Associations persisted when BMIZ and age were included as independent variables in regression models (P < .001 for all). BMIZ and age explained 31%-47% of the variance of C-peptide measures. In an example, 2 individuals with identical AUC C-peptide values had an approximate 5-fold difference in values after adjustments for BMIZ and age. The association between fasting glucose and C-peptide decreased markedly when fasting C-peptide values were adjusted (r = 0.30, P < .01 to r = 0.07, n.s.). CONCLUSIONS: C-peptide measures are strongly and independently related to BMIZ and age at and soon after the diagnosis of T1D. Adjustments for BMIZ and age cause substantial changes in C-peptide values, and impact the association between glycemia and C-peptide. Such adjustments can improve assessments of β-cell impairment at diagnosis

Use of Dried Capillary Blood Sampling for Islet Autoantibody Screening in Relatives:A Feasibility Study

Background: Islet autoantibody testing provides the basis for assessment of risk of progression to type 1 diabetes. We set out to determine the feasibility and acceptability of dried capillary blood spot–based screening to identify islet autoantibody–positive relatives potentially eligible for inclusion in prevention trials. Materials and Methods: Dried blood spot (DBS) and venous samples were collected from 229 relatives participating in the TrialNet Pathway to Prevention Study. Both samples were tested for glutamic acid decarboxylase, islet antigen 2, and zinc transporter 8 autoantibodies, and venous samples were additionally tested for insulin autoantibodies and islet cell antibodies. We defined multiple autoantibody positive as two or more autoantibodies in venous serum and DBS screen positive if one or more autoantibodies were detected. Participant questionnaires compared the sample collection methods. Results: Of 44 relatives who were multiple autoantibody positive in venous samples, 42 (95.5%) were DBS screen positive, and DBS accurately detected 145 of 147 autoantibody-negative relatives (98.6%). Capillary blood sampling was perceived as more painful than venous blood draw, but 60% of participants would prefer initial screening using home fingerstick with clinic visits only required if autoantibodies were found. Conclusions: Capillary blood sampling could facilitate screening for type 1 diabetes prevention studies.</p

Use of self-collected capillary blood samples for islet autoantibody screening in relatives:a feasibility and acceptability study

To evaluate the feasibility of using self-collected capillary blood samples for islet autoantibody testing to identify risk in relatives of people with Type 1 diabetes. Participants were recruited via the observational TrialNet Pathway to Prevention study, which screens and monitors relatives of people with Type 1 diabetes for islet autoantibodies. Relatives were sent kits for capillary blood collection, with written instructions, an online instructional video link and a questionnaire. Sera from capillary blood samples were tested for autoantibodies to glutamic acid decarboxylase, islet antigen-2, insulin and zinc transporter 8. 'Successful' sample collection was defined as obtaining sufficient volume and quality to provide definitive autoantibody results, including confirmation of positive results by repeat assay. In 240 relatives who returned samples, the median (range) age was 15.5 (1-49) years and 51% were male. Of these samples, 98% were sufficient for glutamic acid decarboxylase, islet antigen-2 and zinc transporter 8 autoantibody testing and 84% for insulin autoantibody testing and complete autoantibody screen. The upper 90% confidence bound for unsuccessful collection was 4.4% for glutamic acid decarboxylase, islet antigen-2 and/or zinc transporter 8 autoantibody assays, and 19.3% for insulin autoantibodies. Despite 43% of 220 questionnaire respondents finding capillary blood collection uncomfortable or painful, 82% preferred home self-collection of capillary blood samples compared with outpatient venepuncture (90% of those aged 18 years). The perceived difficulty of collecting capillary blood samples did not affect success rate. Self-collected capillary blood sampling offers a feasible alternative to venous sampling, with the potential to facilitate autoantibody screening for Type 1 diabetes risk

Type 1 Diabetes TrialNet:a multifaceted approach to bringing disease-modifying therapy toclinical use in type 1 diabetes

What will it take to bring disease-modifying therapy to clinical use in type 1 diabetes? Coordinated efforts of investigators involved in discovery, translational, and clinical research operating in partnership with funders and industry and in sync with regulatory agencies are needed. This Perspective describes one such effort, Type 1 Diabetes TrialNet, a National Institutes of Health–funded and JDRF-supported international clinical trials network that emerged from the Diabetes Prevention Trial–Type 1 (DPT-1). Through longitudinal natural history studies, as well as trials before and after clinical onset of disease combined with mechanistic and ancillary investigations to enhance scientific understanding and translation to clinical use, TrialNet is working to bring disease-modifying therapies to individuals with type 1 diabetes. Moreover, TrialNet uses its expertise and experience in clinical studies to increase efficiencies in the conduct of trials and to reduce the burden of participation on individuals and families. Herein, we highlight key contributions made by TrialNet toward a revised understanding of the natural history of disease and approaches to alter disease course and outline the consortium’s plans for the future.</jats:p

Effect of Docosahexaenoic Acid Supplementation on Inflammatory Cytokine Levels in Infants at High Genetic Risk for Type 1 Diabetes

Objective: Type 1 diabetes (T1D) results from the inflammatory destruction of pancreatic β-cells. In this study, we investigated the effect of docosahexaenoic acid (DHA) supplementation on stimulated inflammatory cytokine production in white blood cells (WBC) from infants with a high genetic risk for T1D. Research design and methods: This was a multicenter, two-arm, randomized, double-blind pilot trial of DHA supplementation, beginning either in the last trimester of pregnancy (41 infants) or in the first 5 months after birth (57 infants). Levels of DHA in infant and maternal red blood cell (RBC) membranes and in breast milk were analyzed by gas chromatography/mass spectrometry. Inflammatory cytokines were assayed from whole blood culture supernatants using the Luminex multiplex assay after stimulation with high dose lipopolysaccharide (LPS), 1 µg/mL. Results: The levels of RBC DHA were increased by 61–100% in treated compared to control infants at ages 6–36 months. There were no statistically significant reductions in production of the inflammatory cytokines, IL-1β, TNFα, or IL-12p40 at any of the six timepoints measured. The inflammatory marker, high-sensitivity C-reactive protein (hsCRP), was significantly lower in breast-fed DHA-treated infants compared to all formula-fed infants at the age of 12 months. Three infants (two received DHA) were removed from the study as a result of developing ≥two persistently positive biochemical islet autoantibodies. Conclusions: This pilot trial showed that supplementation of infant diets with DHA is safe and fulfilled the pre-study goal of increasing infant RBC DHA levels by at least 20%. Inflammatory cytokine production was not consistently reduced

Effect of Docosahexaenoic Acid Supplementation on Inflammatory Cytokine Levels in Infants at High Genetic Risk for Type 1 Diabetes

Objective: Type 1 diabetes (T1D) results from the inflammatory destruction of pancreatic β-cells. In this study, we investigated the effect of docosahexaenoic acid (DHA) supplementation on stimulated inflammatory cytokine production in white blood cells (WBC) from infants with a high genetic risk for T1D. Research design and methods: This was a multicenter, two-arm, randomized, double-blind pilot trial of DHA supplementation, beginning either in the last trimester of pregnancy (41 infants) or in the first 5 months after birth (57 infants). Levels of DHA in infant and maternal red blood cell (RBC) membranes and in breast milk were analyzed by gas chromatography/mass spectrometry. Inflammatory cytokines were assayed from whole blood culture supernatants using the Luminex multiplex assay after stimulation with high dose lipopolysaccharide (LPS), 1 µg/mL. Results: The levels of RBC DHA were increased by 61–100% in treated compared to control infants at ages 6–36 months. There were no statistically significant reductions in production of the inflammatory cytokines, IL-1β, TNFα, or IL-12p40 at any of the six timepoints measured. The inflammatory marker, high-sensitivity C-reactive protein (hsCRP), was significantly lower in breast-fed DHA-treated infants compared to all formula-fed infants at the age of 12 months. Three infants (two received DHA) were removed from the study as a result of developing ≥two persistently positive biochemical islet autoantibodies. Conclusions: This pilot trial showed that supplementation of infant diets with DHA is safe and fulfilled the pre-study goal of increasing infant RBC DHA levels by at least 20%. Inflammatory cytokine production was not consistently reduced