Reduced beta-cell function in early preclinical type 1 diabetes

Objective: We aimed to characterize insulin responses to i.v. glucose during the preclinical period of type 1 diabetes starting from the emergence of islet autoimmunity. Design and methods: A large population-based cohort of children with HLA-conferred susceptibility to type 1 diabetes was observed from birth. During regular follow-up visits islet autoantibodies were analysed. We compared markers of glucose metabolism in sequential intravenous glucose tolerance tests between 210 children who were positive for multiple (>= 2) islet autoantibodies and progressed to type 1 diabetes (progressors) and 192 children testing positive for classical islet-cell antibodies only and remained healthy (non-progressors). Results: In the progressors, the first phase insulin response (FPIR) was decreased as early as 4-6 years before the diagnosis when compared to the non-progressors (P=0.001). The difference in FPIR between the progressors and non-progressors was significant (P Conclusions: FPIR is decreased several years before the diagnosis of type 1 diabetes, implying an intrinsic defect in beta-cell mass and/or function.Peer reviewe

Dysregulation of lipid and amino acid metabolism precedes islet autoimmunity in children who later progress to type 1 diabetes

The risk determinants of type 1 diabetes, initiators of autoimmune response, mechanisms regulating progress toward β cell failure, and factors determining time of presentation of clinical diabetes are poorly understood. We investigated changes in the serum metabolome prospectively in children who later progressed to type 1 diabetes. Serum metabolite profiles were compared between sample series drawn from 56 children who progressed to type 1 diabetes and 73 controls who remained nondiabetic and permanently autoantibody negative. Individuals who developed diabetes had reduced serum levels of succinic acid and phosphatidylcholine (PC) at birth, reduced levels of triglycerides and antioxidant ether phospholipids throughout the follow up, and increased levels of proinflammatory lysoPCs several months before seroconversion to autoantibody positivity. The lipid changes were not attributable to HLA-associated genetic risk. The appearance of insulin and glutamic acid decarboxylase autoantibodies was preceded by diminished ketoleucine and elevated glutamic acid. The metabolic profile was partially normalized after the seroconversion. Autoimmunity may thus be a relatively late response to the early metabolic disturbances. Recognition of these preautoimmune alterations may aid in studies of disease pathogenesis and may open a time window for novel type 1 diabetes prevention strategies

Gut Microbiome Metagenomics Analysis Suggests a Functional Model for the Development of Autoimmunity for Type 1 Diabetes

Peer reviewe

Bacteroides dorei dominates gut microbiome prior to autoimmunity in Finnish children at high risk for type 1 diabetes

The incidence of the autoimmune disease, type 1 diabetes (T1D), has increased dramatically over the last half century in many developed countries and is particularly high in Finland and other Nordic countries. Along with genetic predisposition, environmental factors are thought to play a critical role in this increase. As with other autoimmune diseases, the gut microbiome is thought to play a potential role in controlling progression to T1D in children with high genetic risk, but we know little about how the gut microbiome develops in children with high genetic risk for T1D. In this study, the early development of the gut microbiomes of 76 children at high genetic risk for T1D was determined using high-throughput 16S rRNA gene sequencing. Stool samples from children born in the same hospital in Turku, Finland were collected at monthly intervals beginning at 4-6 months after birth until 2.2 years of age. Of those 76 children, 29 seroconverted to T1D-related autoimmunity (cases) including 22 who later developed T1D, the remaining 47 subjects remained healthy (controls). While several significant compositional differences in low abundant species prior to seroconversion were found, one highly abundant group composed of two closely related species, Bacteroides dorei and Bacteroides vulgatus, was significantly higher in cases compared to controls prior to seroconversion. Metagenomic sequencing of samples high in the abundance of the B. dorei/vulgatus group before seroconversion, as well as longer 16S rRNA sequencing identified this group as Bacteroides dorei. The abundance of B. dorei peaked at 7.6 months in cases, over 8 months prior to the appearance of the first islet autoantibody, suggesting that early changes in the microbiome may be useful for predicting T1D autoimmunity in genetically susceptible infants. The cause of increased B. dorei abundance in cases is not known but its timing appears to coincide with the introduction of solid food.</p

Participant Experiences in the Environmental Determinants of Diabetes in the Young Study : Common Reasons for Withdrawing

M. Knip on TEDDY Study Grp -työryhmän jäsen.Background. To characterize participant reasons for withdrawing from a diabetes focused longitudinal clinical observational trial (TEDDY) during the first three study years. Methods. 8677 children were recruited into the TEDDY study. At participant withdrawal staff recorded any reason parents provided for withdrawal. Reasons were categorized into (1) family characteristics and (2) protocol reasons. Families who informed staff of their withdrawal were classified as active withdrawals (AW); families without a final contact were considered passive withdrawals (PW). Results. Withdrawal was highest during the first study year (n = 1220). Most families were AW(n = 1549; 73.4%). PW was more common in the United States (n = 1001; 37.8%) and among young mothers (p = 0.001). The most frequent protocol characteristic was blood draw (55%) and the most common family reason was not having enough time (66%). The blood draw was more common among female participants; being too busy was more common among males. Both reasons were associated with study satisfaction. Conclusions. Results suggest that, for families of children genetically at risk for diabetes, procedures that can be painful/frightening should be used with caution. Study procedures must also be considered for the demands placed on participants. Study satisfaction should be regularly assessed as an indicator of risk for withdrawal.Peer reviewe

Bacteroides dorei dominates gut microbiome prior to autoimnnunity in Finnish children at high risk for type 1 diabetes

Peer reviewe

The Effects of Type 1 Diabetes and its Long-Term Complications on Physical and Mental Health Status

Objective: To analyse how type 1 diabetes mellitus (DM) and the symptoms of its chronic long-term complications correlate with health status domains in the adult population in Finland. Methods: A representative sample of patients with type 1 DM was selected randomly from the Finnish drug reimbursement registry. Participants reported symptoms, diagnoses and treatments indicating the presence and time of appearance of long-term complications, and completed the RAND 36 questionnaire. A principal component analysis was performed to compress the eight RAND 36 dimensions into composite domains of health status. The results were validated with split-sample analysis. Regression analyses were used to estimate the effects of age, sex, symptoms of long-term complications and comorbidities on the component T-scores. Results: Of the 752 (70.8%) responders, 592 fulfilled the criteria of type 1 DM. Of these, 82.6% fully completed the RAND 36 questionnaire. Principal component analysis of our data supports the theory of the 2-factor model of health, as physical and mental health domains were reflected unambiguously by different RAND 36 dimensions. The regression results show that the symptoms of long-term complications correlate more strongly with the physical than the mental domain of health status. Conclusion: Type 1 DM, and especially the symptoms of its long-term complications, correlate mainly with the physical domain of health, although the mental domain is also affected. The prevalence of long-term complications with type 1 DM is sufficiently high within the Finnish population to substantially influence the health status of people with type 1 DM.Quality-of-life, Type-1-diabetes-mellitus