Anne Hekkala

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.

Nasal insulin to prevent type 1 diabetes in children with HLA genotypes and autoantibodies conferring increased risk of disease: a double-blind, randomised controlled trial

BACKGROUND In mouse models of diabetes, prophylactic administration of insulin reduced incidence of the disease. We investigated whether administration of nasal insulin decreased the incidence of type 1 diabetes, in children with HLA genotypes and autoantibodies increasing the risk of the disease. METHODS At three university hospitals in Turku, Oulu, and Tampere (Finland), we analysed cord blood samples of 116 720 consecutively born infants, and 3430 of their siblings, for the HLA-DQB1 susceptibility alleles for type 1 diabetes. 17 397 infants and 1613 siblings had increased genetic risk, of whom 11 225 and 1574, respectively, consented to screening of diabetes-associated autoantibodies at every 3-12 months. In a double-blind trial, we randomly assigned 224 infants and 40 siblings positive for two or more autoantibodies, in consecutive samples, to receive short-acting human insulin (1 unit/kg; n=115 and n=22) or placebo (n=109 and n=18) once a day intranasally. We used a restricted randomisation, stratified by site, with permuted blocks of size two. Primary endpoint was diagnosis of diabetes. Analysis was by intention to treat. The study was terminated early because insulin had no beneficial effect. This study is registered with ClinicalTrials.gov, number NCT00223613. FINDINGS Median duration of the intervention was 1.8 years (range 0-9.7). Diabetes was diagnosed in 49 index children randomised to receive insulin, and in 47 randomised to placebo (hazard ratio [HR] 1.14; 95% CI 0.73-1.77). 42 and 38 of these children, respectively, continued treatment until diagnosis, with yearly rates of diabetes onset of 16.8% (95% CI 11.7-21.9) and 15.3% (10.5-20.2). Seven siblings were diagnosed with diabetes in the insulin group, versus six in the placebo group (HR 1.93; 0.56-6.77). In all randomised children, diabetes was diagnosed in 56 in the insulin group, and 53 in the placebo group (HR 0.98; 0.67-1.43, p=0.91). INTERPRETATION In children with HLA-conferred susceptibility to diabetes, administration of nasal insulin, started soon after detection of autoantibodies, could not be shown to prevent or delay type 1 diabetes.

Predictive Characteristics of Diabetes-Associated Autoantibodies Among Children With HLA-Conferred Disease Susceptibility in the General Population

OBJECTIVE As data on the predictive characteristics of diabetes-associated autoantibodies for type 1 diabetes in the general population are scarce, we assessed the predictive performance of islet cell autoantibodies (ICAs) in combination with autoantibodies against insulin (IAAs), autoantibodies against GAD, and/or islet antigen 2 for type 1 diabetes in children with HLA-defined disease predisposition recruited from the general population. RESEARCH DESIGN AND METHODS We observed 7,410 children from birth (median 9.2 years) for β-cell autoimmunity and diabetes. If a child developed ICA positivity or diabetes, the three other antibodies were measured in all samples available from that individual. Persistent autoantibody positivity was defined as continued positivity in at least two sequential samples including the last available sample. RESULTS Pre-diabetic ICA positivity was observed in 1,173 subjects (15.8%), 155 of whom developed type 1 diabetes. With ICA screening, 86% of 180 progressors (median age at diagnosis 5.0 years) were identified. Positivity for four antibodies was associated with the highest disease sensitivity (54.4%) and negative predictive values (98.3%) and the lowest negative likelihood ratio (0.5). The combination of persistent ICA and IAA positivity resulted in the highest positive predictive value (91.7%), positive likelihood ratio (441.8), cumulative disease risk (100%), and specificity (100%). Young age at seroconversion, high ICA level, multipositivity, and persistent positivity for IAA were significant risk markers for type 1 diabetes. CONCLUSIONS Within the general population, the combination of HLA and autoantibody screening resulted in disease risks that are likely to be as high as those reported among autoantibody-positive siblings of children with type 1 diabetes.

Ketoacidosis at diagnosis of type 1 diabetes in children in northern Finland: temporal changes over 20 years.

OBJECTIVE—To study the frequency of diabetic ketoacidosis (DKA) over a 20-year period among children diagnosed with type 1 diabetes in northern Finland. RESEARCH DESIGN AND METHODS—The study population comprised 585 patients (328 boys) diagnosed with type 1 diabetes aged <15 years in the Department of Pediatrics, Oulu University Hospital, between 1 January 1982 and 31 December 2001. The data for clinical characteristics were collected retrospectively from the patients’ case records. The earlier 10-year period (1982–1991) was compared with the later 10-year period (1992–2001). Two definitions for DKA were used: DKA(i) pH <7.30 or DKA(ii) pH <7.30 and/or bicarbonate <15 mmol/l. RESULTS—During the later 10-year period, children less often had DKA at diagnosis [DKA(i) 15.2 vs. 22.4%, P = 0.028, and DKA(ii) 18.9 vs. 29.5%, P = 0.003]. The proportion of young children aged <5 years at diagnosis increased over time, but the frequency of DKA also was lower in this age-group during 1992–2001 compared with the earlier 10-year period [DKA(i) 17.7 vs. 32.1%, P = 0.052, and DKA(ii) 20.3 vs. 42.6%, P = 0.005]. In children aged <2 years at diagnosis, the frequency of DKA remained high during 1992–2001 [DKA(i) 39.1% and DKA(ii) 47.8%]. CONCLUSIONS—The overall frequency of DKA in children with newly diagnosed type 1 diabetes decreased over a 20-year period in northern Finland. However, children aged <2 years are still at high risk for DKA at diagnosis.

Fate of Five Celiac Disease-Associated Antibodies During Normal Diet in Genetically At-Risk Children Observed from Birth in a Natural History Study

OBJECTIVES: To explore the natural history of antibodies against tissue transglutaminase (TGA), endomysium (EMA), reticulin (ARA), and gliadin (AGA-IgG and AGA-IgA) in children carrying HLA-conferred risk for celiac disease (CD) and observed frequently from birth.METHODS: TGA was measured in serum samples obtained between years 2000 and 2003 from 1,320 children carrying genetic CD risk. If a sample was TGA positive, all five antibodies were analyzed in all banked and forthcoming samples from that child, and a duodenal biopsy was recommended. At the end of this observation, in August 2004, the age of the children was from 1 to 9.5 yr (mean 4.1 yr).RESULTS: Forty-nine children (3.7%) were TGA positive. In these children, AGA-IgG had emerged at the mean age (± SD, range) of 2.0 ± 1.5, 0.5–6.6 yr, while TGA, EMA, and ARA all emerged concurrently somewhat later (TGA at 3.2 ± 1.5, 1.0–7.0 yr, P < 0.001 when compared to AGA-IgG). Despite continuing gluten exposure, positive TGA, EMA, ARA, AGA-IgA, and AGA-IgG values were spontaneously lost in 49%, 45%, 43%, 41%, and 32% of the children, respectively. CD was diagnosed by biopsy in 20 of the 26 TGA-positive children who consented to a biopsy.CONCLUSIONS: Potential CD trigger(s) other than only gluten probably function before AGA-IgG emerges, i.e., ≥3 months earlier than the transglutaminase-associated antibodies appear. In a remarkable proportion of the children, antibodies disappear spontaneously suggesting that regulatory immune phenomena under favorable circumstances are able to extinguish incipient CD in genetically at-risk children even without exclusion of gluten from the diet.

Natural history of transglutaminase autoantibodies and mucosal changes in children carrying HLA-conferred celiac disease susceptibility.

OBJECTIVE The natural history of the appearance and fate of transglutaminase autoantibodies (TGAs) and mucosal changes in children carrying HLA-conferred celiac disease (CD) risk remains obscure. The aim of this study was to investigate the sequence of events leading to overt CD by retrospective analysis of TGA values in serum samples collected frequently from genetically susceptible children since birth or early childhood. MATERIAL AND METHODS A total of 1101 at-risk children were recruited in the study. A duodenal biopsy was recommended to all TGA-positive children and performed if parental consent was obtained. RESULTS During up to 8 years of follow-up, 35 of the cohort children developed TGAs, the youngest at age 1.3 years. After age 1.3 years the annual TGA seroconversion rate was constantly around 1% at least until age 6 years. However, 18 of the 35 TGA-positive children (51%) lost TGAs, without any dietary manipulation. A further 7 children were IgA deficient; of these children, 2 developed IgG antigliadin antibodies (IgG-AGA). Only 13 of the 21 children (62%) who had duodenal biopsies had villous atrophy. The time that passed since emergence of TGAs failed to predict the biopsy findings. Only one of the children with TGAs and both of the IgA-deficient children with IgG-AGA had noticeable abdominal symptoms. CONCLUSIONS TGAs appear in children at a constant rate after 1 year of age until at least the age of 6 years. Over half of the children loose TGA without gluten exclusion, challenging TGA positivity-based CD prevalence estimates. In symptom-free children, a requirement of two consecutive TGA-positive samples taken >or=3 months apart before performing a duodenal biopsy might diminish the number of unnecessary intestinal biopsies.

Age-Related Differences in the Frequency of Ketoacidosis at Diagnosis of Type 1 Diabetes in Children and Adolescents

OBJECTIVE We studied the prevalence of diabetic ketoacidosis (DKA) at diagnosis of type 1 diabetes in children in Finland. RESEARCH DESIGN AND METHODS From 2002 to 2005, data on virtually all children <15 years of age diagnosed with type 1 diabetes (n = 1,656) in Finland were collected. RESULTS DKA was present in 19.4% of the case subjects, and 4.3% had severe DKA. In children aged 0–4, 5–9, and 10–14 years, DKA was present in 16.5, 14.8, and 26.4%, respectively (P < 0.001). Severe DKA occurred in 3.7, 3.1, and 5.9%, respectively (P = 0.048). DKA was present in 30.1% and severe DKA in 7.8% of children aged <2 years. CONCLUSION The overall frequency of DKA in children is low in Finland at diagnosis of type 1 diabetes. However, both children <2 years of age and adolescents aged 10–14 years are at increased risk of DKA.

Infant feeding patterns in the Finnish type I diabetes prediction and prevention nutrition study cohort

Objective: To investigate infant feeding patterns during the first 2 y and their relation to sociodemographic factors.Design: A population-based cohort study.Setting: Oulu and Tampere University Hospital district areas 1996–1999, Finland.Subjects and methods: All newborn infants (n=675) with increased genetic risk for type I diabetes were invited to the study in 1996–1997. Of these, 429 (64%) completed the dietary follow-up form by the time they reached 2 y of age.Results: The median duration of exclusive breastfeeding (BF) was 1.8 months (range 0–6 months) and that of total BF 7.0 months (0.3–25 months). Among the infants 20% were exclusively breastfed at least 4 months (recommendation 4–6 months). Infants were introduced to infant formula at the median age of 1.8 months (range 0–25 months) and other supplementary foods at the median age of 3.5 months (1–6 months). Infants ponderal index at birth was inversely associated with the duration of total BF. The age of introduction of supplementary foods correlated positively with the duration of total BF. Longer parental education and increased maternal age were associated with a longer duration of BF and older age at introduction of supplementary foods. Infant formula and other supplementary foods were added earlier to the diet of the boys than that of the girls.Conclusion: Duration of breastfeeding in Finland is shorter than recommended. Compliance with the current recommendations on the timing of introduction of first supplementary food and dairy products is relatively poor. The diet during infancy seems to be conspicuously influenced by the duration of parental education, maternal age and the sex of the infant.

Family history of diabetes and distribution of class II HLA genotypes in children with newly diagnosed type 1 diabetes: effect on diabetic ketoacidosis

OBJECTIVE Our purpose was to assess whether family history of diabetes or the HLA-DR-DQ genotype of the index case was associated with the frequency of diabetic ketoacidosis (DKA) at diagnosis of childhood type 1 diabetes. PATIENTS AND METHODS The study cohort comprised 1518 children aged <15 years and diagnosed with type 1 diabetes in Finland in 2002-2005. Family history of type 1 and type 2 diabetes among first-degree relatives (FDRs) and grandparents was assessed at diagnosis. HLA-DR-DQ genotypes were analysed using time-resolved fluorometry. RESULTS In total, 12.6 and 1.7% of children had at least one FDR affected with type 1 or type 2 diabetes, respectively, and 6.6 and 34.8% had at least one grandparent with type 1 or type 2 diabetes. DKA (pH <7.30) occurred less frequently in children having a type 1 diabetes affected FDR (7.4 vs 20.5%, P<0.001). Type 2 diabetes among the parents or grandparents had no such effect. Lower risk HLA genotypes were observed to predispose to DKA (P<0.024). In a logistic regression analysis, the risk of DKA was independently associated with the absence of a family member affected by type 1 diabetes, the presence of a low-risk HLA genotype and older age at diagnosis (odds ratio 3.23, 1.45 and 1.07 respectively). CONCLUSION The presence of type 1 diabetes in an FDR is associated with an decreased risk of DKA at diagnosis. The rate of DKA seems to be higher in children with lower HLA-conferred risk for type 1 diabetes.

IA-2 antibody isotypes and epitope specificity during the prediabetic process in children with HLA-conferred susceptibility to type I diabetes

The natural history of preclinical diabetes is partly characterized, but there is still limited information on the dynamics of the immune response to β‐cell autoantigens during the course of preclinical disease. The aim of this work was to assess the maturation of the humoral immune response to the protein tyrosine phosphatase(PTP)‐related proteins (IA‐2 and IA‐2β) in preclinical type I diabetes (TID). Forty‐five children participating in the Finnish Type I Diabetes Prediction and Prevention (DIPP) Study who had seroconverted to IA‐2 antibody positivity were analysed. Specific radiobinding assays were used to determine IA‐2/IA‐2β epitope‐specific antibodies (the juxtamembrane (JM) region of IA‐2, PTP‐like domain and βPTP‐like domain) and isotype‐specific IA‐2 antibodies. Individual areas under the curve (AUC) over the observation period were calculated for total IA‐2 antibodies, each isotype and specific epitope responses. The children who progressed to TID tended to have an initial IA‐2 JM epitope response more frequently (P = 0·06), and this response was more often dominant during the observation period (P < 0·05). The children who did not progress to TID had IgE‐IA‐2 more frequently (70%; versus progressors 27%; P < 0·05), and had higher integrated titres of IgE‐IA‐2 antibodies (P < 0·05). The occurrence of IgE‐IA‐2 antibodies was protective even when combined with positivity for IA‐2 JM antibodies (P = 0·002). IgE‐IA‐2 antibody reactivity may be a marker of a regulatory immune response providing protection against or delaying progression to TID among IA‐2 antibody‐positive young children with HLA‐conferred disease susceptibility.