The four components of dysglycemia were not equally affected by the degree of islet graft function, which could have important implications for future development of β-cell replacement. A β-score above 3 dramatically reduced the occurrence of hypoglycemia.

No abstract

Introduction: Gitelman syndrome (GS) is a tubulopathy caused by SLC12A3 gene mutations, which lead to hypokalaemic alkalosis, secondary hyperaldosteronism, hypomagnesaemia and hypocalciuria. Aim: The aim of this study was to assess the prevalence of SLC12A3 gene mutations in adult hypokalaemic patients; to compare the phenotype of homozygous, heterozygous and non-mutated patients; and to determine the efficiency of treatment. Methods: Clinical, biological and genetic data were recorded in 26 patients. Results: Screening for the SLC12A3 gene detected two mutations in 15 patients (six homozygous and nine compound heterozygous), one mutation in six patients and no mutation in five patients. There was no statistical difference in clinical symptoms at diagnosis between the three groups. Systolic blood pressure tended to be lower in patients with two mutations (PZ0.16). Hypertension was unexpectedly detected in four patients. Five patients with two mutated alleles and two with heterozygosity had severe manifestations of GS. Significant differences were observed between the three groups in blood potassium, chloride, magnesium, supine aldosterone, 24 h urine chloride and magnesium levels and in modification of the diet in renal disease. Mean blood potassium levels increased from 2.8G0.3, 3.5 G0.5 and 3.2G0.3 before treatment to 3.2G0.5, 3.7G0.6 and 3.7G0.3 mmol/l with treatment in groups with two (PZ0.003), one and no mutated alleles respectively. Conclusion: In adult patients referred for renal hypokalaemia, we confirmed the presence of mutations of the SLC12A3 gene in 80% of cases. GS was more severe in patients with two mutated alleles than in those with one or no mutated alleles. High blood pressure should not rule out the diagnosis, especially in older patients.

Objective: Hypothyroidism is a manifestation of multi-hormonal resistance in pseudohypoparathyroidism type Ia (PHP Ia). The objective of the study was to determine the mechanisms of hypothyroidism in PHP Ia. Design: A prospective study. Patients: Ten patients with PHP Ia. Measurements: The serum concentrations of TSH, free triiodothyronine (FT 3 ), free thyroxine (FT 4 ), and prolactin (PRL) were measured at baseline and after stimulation with TRH (200 mg i.v). Results: The median basal serum TSH concentration was 4.92 mU/l. Basal serum TSH concentration was slightly elevated in eight patients (4.22-7.0 mU/l; normal range, 0.4-3.6 mU/l), normal in one patient (2.5 mU/l), and high in one patient (13.1 mU/l). After the TRH test, TSH concentrations increased to 13.4-36.0 mU/l (normal range, 4.0-20.0 mU/l). The absolute values after the test were normal in three patients and high in seven patients. However, TSH responses relative to the baseline value (stimulated/basal TSH and expressed as a fold increase), which reflect the relative increases after TRH stimulation, were low in seven patients (2.3-to 4.3-fold TSH) and normal in three patients. Basal FT 4 concentration was normal in seven patients and low in three patients (range, 8.4-20.0 pmol/l; mean, 14.1G4.3 pmol/l; normal range, 10.5-23.0 pmol/l). Basal FT 3 concentration was normal in nine patients and low in one patient (range, 0.9-5.0 pmol/l; mean, 3.8G1.1 pmol/l; normal range, 3.3-6.1 pmol/l). FT 4 and FT 3 were not significantly increased after the TRH test. PRL concentration was normal at baseline and increased from 7 to 96 ng/ml after TRH. Conclusion: Our results support the hypothesis that patients with PHP Ia have impaired sensitivity to both TSH and TRH.

Zinc ions are essential for the formation of insulin crystals in pancreatic b cells, thereby contributing to packaging efficiency of stored insulin. Zinc fluxes are regulated through the SLC30A (zinc transporter, ZNT) family. Here, we investigated the effect of metabolic stress associated with the prediabetic state (zinc depletion, glucotoxicity, and lipotoxicity) on ZNT expression and human pancreatic islet function. Both zinc depletion and lipotoxicity (but not glucotoxicity) downregulated ZNT8 (SLC30A8) expression and altered the glucose-stimulated insulin secretion index (GSIS). ZNT8 overexpression in human islets protected them from the decrease in GSIS induced by tetrakis-(2-pyridylmethyl) ethylenediamine and palmitate but not from cell death. In addition, zinc supplementation decreased palmitate-induced human islet cell death without restoring GSIS. Altogether, we showed that ZNT8 expression responds to variation in zinc and lipid levels in human b cells, with repercussions on insulin secretion. Prospects for increasing ZNT8 expression and/or activity may prove beneficial in type 2 diabetes in humans.

No abstract

No abstract

No abstract