References of "Gammeltoft, S."
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See detailCo-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
Nielsen, L. B.; Ploug, K. B.; Swift, P. et al

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 ▲]

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See detailImpact of IDDM2 on disease pathogenesis and progression in children with newly diagnosed type 1 diabetes: Reduced insulin antibody titres and preserved beta cell function
Nielsen, L. B.; Mortensen, H. B.; Chiarelli, F. et al

in Diabetologia (2006), 49(1), 71-74

Aims/hypothesis: The insulin-dependent diabetes mellitus 2 gene (IDDM2) is a type 1 diabetes susceptibility locus contributed to by the variable number of tandem repeats (VNTR) upstream of the insulin ... [more ▼]

Aims/hypothesis: The insulin-dependent diabetes mellitus 2 gene (IDDM2) is a type 1 diabetes susceptibility locus contributed to by the variable number of tandem repeats (VNTR) upstream of the insulin gene (INS). We investigated the association between INS VNTR class III alleles (-23HphIA/T) and both insulin antibody presentation and residual beta cell function during the first year after diagnosis in 257 children with type 1 diabetes. Materials and methods: To estimate C-peptide levels and autoantibody presentation, patients underwent a meal-stimulated C-peptide test 1, 6, and 12 months after diagnosis. The insulin -23HphIA/T variant was used as a marker of class III alleles and genotyped by PCR-RFLP. Results: The insulin antibody titres at 1 and 6 months were significantly lower in the class III/III and class I/III genotype groups than in the class I/I genotype group (p = 0.01). Class III alleles were also associated with residual beta cell function 12 months after diagnosis and independently of age, sex, BMI, insulin antibody titres, and HLA-risk genotype group (p = 0.03). The C-peptide level was twice as high among class III/III genotypes as in class I/I and class I/III genotypes (319 vs 131 and 166 pmol/l, p=0.01). Furthermore, the class III/III genotype had a 1.1% reduction in HbA1c after adjustment for insulin dose (p = 0.04). Conclusions/interpretation: These findings suggest a direct connection in vivo between INS VNTR class III alleles, a decreased humoral immune response to insulin, and preservation of beta cell function in recent-onset type 1 diabetes. © Springer-Verlag 2005. [less ▲]

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