The genetic and regulatory architecture of ERBB3-type 1 diabetes susceptibility locus

in Molecular and Cellular Endocrinology (2016), 419

The study aimed to explore the role of ERBB3 in type 1 diabetes (T1D). We examined whether genetic variation of ERBB3 (rs2292239) affects residual β-cell function in T1D cases. Furthermore, we examined ... [more ▼]

The study aimed to explore the role of ERBB3 in type 1 diabetes (T1D). We examined whether genetic variation of ERBB3 (rs2292239) affects residual β-cell function in T1D cases. Furthermore, we examined the expression of ERBB3 in human islets, the effect of ERBB3 knockdown on apoptosis in insulin-producing INS-1E cells and the genetic and regulatory architecture of the ERBB3 locus to provide insights to how rs2292239 may confer disease susceptibility. rs2292239 strongly correlated with residual β-cell function and metabolic control in children with T1D. ERBB3 locus associated lncRNA (NONHSAG011351) was found to be expressed in human islets. ERBB3 was expressed and down-regulated by pro-inflammatory cytokines in human islets and INS-1E cells; knockdown of ERBB3 in INS-1E cells decreased basal and cytokine-induced apoptosis. Our data suggests an important functional role of ERBB3 and its potential regulators in the β-cells and may constitute novel targets to prevent β-cell destruction in T1D. © 2015 Elsevier Ireland Ltd. [less ▲]

Metabolic outcomes in young children with type 1 diabetes differ between treatment centers: the Hvidoere Study in Young Children 2009

in Pediatric Diabetes (2012), 14(6), 422-428

Objective: To investigate whether center differences in glycemic control are present in prepubertal children <11 yr with type 1 diabetes mellitus. Research Design and Methods: This cross-sectional study ... [more ▼]

Objective: To investigate whether center differences in glycemic control are present in prepubertal children <11 yr with type 1 diabetes mellitus. Research Design and Methods: This cross-sectional study involved 18 pediatric centers worldwide. All children, <11 y with a diabetes duration ≥12 months were invited to participate. Case Record Forms included information on clinical characteristics, insulin regimens, diabetic ketoacidosis (DKA), severe hypoglycemia, language difficulties, and comorbidities. Hemoglobin A1c (HbA1c) was measured centrally by liquid chromatography (DCCT aligned, range: 4.4-6.3%; IFFC: 25-45 mmol/mol). Results: A total of 1133 children participated (mean age: 8.0 ± 2.1 y; females: 47.5%, mean diabetes duration: 3.8 ± 2.1 y). HbA1c (overall mean: 8.0 ± 1.0%; range: 7.3-8.9%) and severe hypoglycemia frequency (mean 21.7 events per 100 patient-years), but not DKA, differed significantly between centers (p < 0.001 resp. p = 0.179). Language difficulties showed a negative relationship with HbA1c (8.3 ± 1.2% vs. 8.0 ± 1.0%; p = 0.036). Frequency of blood glucose monitoring demonstrated a significant but weak association with HbA1c (r = -0.17; p < 0.0001). Although significant different HbA1c levels were obtained with diverse insulin regimens (range: 7.3-8.5%; p < 0.001), center differences remained after adjusting for insulin regimen (p < 0.001). Differences between insulin regimens were no longer significant after adjusting for center effect (p = 0.199). Conclusions: Center differences in metabolic outcomes are present in children <11 yr, irrespective of diabetes duration, age, or gender. The incidence of severe hypoglycemia is lower than in adolescents despite achieving better glycemic control. Insulin regimens show a significant relationship with HbA1c but do not explain center differences. Each center's effectiveness in using specific treatment strategies remains the key factor for outcome. [less ▲]

Target setting in intensive insulin management is associated with metabolic control: The Hvidoere Childhood Diabetes Study Group Centre Differences Study 2005

in Pediatric Diabetes (2010), 11(4), 271-278

Objective: To evaluate glycaemic targets set by diabetes teams, their perception by adolescents and parents, and their influence on metabolic control.Methods: Clinical data and questionnaires were ... [more ▼]

Objective: To evaluate glycaemic targets set by diabetes teams, their perception by adolescents and parents, and their influence on metabolic control.Methods: Clinical data and questionnaires were completed by adolescents, parents/carers and diabetes teams in 21 international centres. HbA1c was measured centrally.Results: A total of 2062 adolescents completed questionnaires (age 14.4 ± 2.3 yr; diabetes duration 6.1 ± 3.5 yr). Mean HbA 1c = 8.2 ± 1.4% with significant differences between centres (F = 12.3; p < 0.001) range from 7.4 to 9.1%. There was a significant correlation between parent (r = 0.20) and adolescent (r = 0.21) reports of their perceived ideal HbA1c and their actual HbA1c result (p < 0.001), and a stronger association between parents' (r = 0.39) and adolescents' (r = 0.4) reports of the HbA1c they would be happy with and their actual HbA1c result. There were significant differences between centres on parent and adolescent reports of ideal and happy with HbA1c (8.1 < F > 17.4;p < 0.001). A lower target HbA1c and greater consistency between members of teams within centres were associated with lower centre HbA1c (F = 16.0; df = 15; p < 0.001).Conclusions: Clear and consistent setting of glycaemic targets by diabetes teams is strongly associated with HbA1c outcome in adolescents. Target setting appears to play a significant role in explaining the differences in metabolic outcomes between centres. © 2009 John Wiley & Sons A/S. [less ▲]

New definition for the partial remission period in children and adolescents with type 1 diabetes

in Diabetes Care (2009), 32(8), 1384-1390

OBJECTIVE - To find a simple definition of partial remission in type 1 diabetes that reflects both residual β-cell function and efficacy of insulin treatment. RESEARCH DESIGN AND METHODS - A total of 275 ... [more ▼]

OBJECTIVE - To find a simple definition of partial remission in type 1 diabetes that reflects both residual β-cell function and efficacy of insulin treatment. RESEARCH DESIGN AND METHODS - A total of 275 patients aged <16 years were followed from onset of type 1 diabetes. After 1, 6, and 12 months, stimulated C-peptide during a challenge was used as a measure of residual β-cell function. RESULTS - By multiple regression analysis, a negative association between stimulated C-peptide and A1C (regression coefficient -0.21, P < 0.001) and insulin dose (-0.94, P < 0.001) was shown. These results suggested the definition of an insulin dose-adjusted A1C (IDAA1C) as A1C (percent) + [4 × insulin dose (units per kilogram per 24 h)]. A calculated IDAA1C ≤9 corresponding to a predicted stimulated C-peptide >300 pmol/l was used to define partial remission. The IDAA1C ≤9 had a significantly higher agreement (P < 0.001) with residual β-cell function than use of a definition of A1C ≤7.5%. Between 6 and 12 months after diagnosis, for IDAA1C ≤9 only 1 patient entered partial remission and 61 patients ended partial remission, for A1C ≤7.5% 15 patients entered partial remission and 53 ended, for a definition of insulin dose ≤0.5 units · kg-1 · 24 h-1 5 patients entered partial remission and 66 ended, and for stimulated C-peptide (>300 pmol/l) 9 patients entered partial remission and 49 ended. IDAA1C at 6 months has good predictive power for stimulated C-peptide concentrations after both 6 and 12 months. CONCLUSIONS - A new definition of partial remission is proposed, including both glycemic control and insulin dose. It reflects residual β-cell function and has better stability compared with the conventional definitions. © 2009 by the American Diabetes Association. [less ▲]

Co-localisation of the Kir6.2/SUR1 channel complex with glucagon-like peptide-1 and glucose-dependent insulinotrophic polypeptide expression in human ileal cells and implications for glycaemic control in new onset type 1 diabetes

in European Journal of Endocrinology (2007), 156(6), 663-671

Objective: The ATP-dependent K+-channel (KATP) is critical for glucose sensing and normal glucagon and insulin secretion from pancreatic endocrine α- and β-cells. Gastrointestinal endocrine L- and K-cells ... [more ▼]

Objective: The ATP-dependent K+-channel (KATP) is critical for glucose sensing and normal glucagon and insulin secretion from pancreatic endocrine α- and β-cells. Gastrointestinal endocrine L- and K-cells are also glucose-sensing cells secreting glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotrophic polypeptide (GIP) respectively. The aims of this study were to 1) investigate the expression and co-localisation of the KATP channel subunits, Kir6.2 and SUR1, in human L- and K-cells and 2) investigate if a common hyperactive variant of the Kir6.2 subunit, Glu2Lys, exerts a functional impact on glucose-sensing tissues in vivo that may affect the overall glycaemic control in children with new-onset type 1 diabetes. Design and methods: Western blot and immunohistochemical analyses were performed for expression and co-localisation studies. Meal-stimulated C-peptide test was carried out in 257 children at 1, 6 and 12 months after diagnosis. Genotyping for the Glu23Lys variant was by PCR-restriction fragment length polymorphism. Results: Kir6.2 and SUR1 co-localise with GLP-1 in L-cells and with GIP in K-cells in human ileum tissue. Children with type 1 diabetes carrying the hyperactive Glu23Lys variant had higher HbA1c at diagnosis (coefficient= 0.61%, P= 0.02) and 1 month after initial insulin therapy (coefficient= 0.30%, P=0.05), but later disappeared. However, when adjusting HbA1c for the given dose of exogenous insulin, the dose-adjusted HbA1c remained higher throughout the 12 month study period (coefficient= 0.42%, P=0.03). Conclusions: Kir6.2 and SUR1 co-localise in the gastrointestinal endocrine L- and K-cells. The hyperactive Glu2Lys variant of the KATP channel subunit Kir6.2 may cause defective glucose sensing in several tissues and impaired glycaemic control in children with type 1 diabetes. © 2007 Society of the European Journal of Endocrinology. [less ▲]

17 The epidemiology and immunogenetics of IDDM in Italian-heritage populations. Diabetes Epidemiology Research International (DERI) Study Group

in Diabetes/Metabolism Reviews (1990), 6