Small-molecule inhibitors of the cystic fibrosis transmembrane conductance regulator increase pancreatic endocrine cell development in rat and mouse.

AIMS/HYPOTHESIS: The main objective of this work was to discover new drugs that can activate the differentiation of multipotent pancreatic progenitors into endocrine cells. METHODS: In vitro experiments were performed using fetal pancreatic explants from rats and mice. In this assay, we examined the actions on pancreatic cell development of glibenclamide, a sulfonylurea derivative, and glycine hydrazide (GlyH-101), a small-molecule inhibitor of cystic fibrosis transmembrane conductance regulator (CFTR). We next tested the actions of GlyH-101 on in vivo pancreatic cell development. RESULTS: Glibenclamide (10 nmol/l-100 µmol/l) did not alter the morphology or growth of the developing pancreas and exerted no deleterious effects on exocrine cell development in the pancreas. Unexpectedly, glibenclamide at its highest concentration promoted endocrine differentiation. This glibenclamide-induced promotion of the endocrine pathway could not be reproduced when other sulfonylureas were used, suggesting that glibenclamide had an off-target action. This high concentration of glibenclamide had previously been reported to inhibit CFTR. We found that the effects of glibenclamide on the developing pancreas could be mimicked both in vitro and in vivo by GlyH-101. CONCLUSIONS/INTERPRETATION: Collectively, we demonstrate that two small-molecule inhibitors of the CFTR, glibenclamide and GlyH-101, increase the number of pancreatic endocrine cells by increasing the size of the pool of neurogenin 3-positive endocrine progenitors in the developing pancreas.

Evaluation of catch-up growth in severe pediatric Hashimoto's hypothyroidism.

BACKGROUND: We aimed to evaluate catch-up growth in children with severe Hashimoto's hypothyroidism (HH) after thyroid hormone replacement therapy (HRT). METHODS: A multicenter retrospective study was conducted including children referred for growth slowdown that led to the diagnosis of HH between 1998 and 2017. RESULTS: A total of 29 patients were included, with a median age of 9.7 years (13-172 months). Median height at diagnosis was -2.7 [-4.6; -0.1] standard deviation score (SDS), with a height loss of 2.5 [0.7; 5.4] SDS compared to height before growth deflection (p<0.0001). At diagnosis, the median TSH level was 819.5 mIU/L [100; 1844], the median FT4 level was 0 pmol/L [undetectable; 5.4], and the median anti-thyroperoxidase antibody level was 1601 UI/L [47; 25,500]. In the 20 patients treated only with HRT, there were significant differences between height at diagnosis and height at 1 year (n = 19, p<0.0001), 2 years (n = 13, p = 0.0005), 3 years (n = 9, p = 0.0039), 4 years (n = 10, p = 0.0078), and 5 years (n = 10, p = 0.0018) of treatment but not in the case of final height (n = 6, p = 0.0625). Median final height was -1.4 [-2.7; 1,5] SDS (n = 6), with a significant difference between height loss at diagnosis and total catch-up growth (p = 0.003). The other nine patients were also given growth hormone (GH). They were smaller at diagnosis (p = 0.01); however, there was no difference in final height between those two groups (p = 0.68). CONCLUSION: Severe HH can lead to a major height deficit, and catch-up growth seems to be insufficient after treatment with HRT alone. In the most severe cases, administration of GH may enhance this catch-up.

[Diagnosis of delayed puberty]. / Diagnostic des retards pubertaires.

Puberty is the phenomenon that conducts once to reproductive maturation. Delayed puberty (DP) is defined by the absence of testicular development in boys beyond 14 years old (or a testicular volume lower than 4 ml) and by the absence of breast development in girls beyond 13 years old. DP occurs in approximatively 3% of cases. Most cases are functional DP, with a large amount of constitutional delay of puberty. Others etiologies are hypogonadotrophic hypogonadism like Kallmann syndrome, or hypergonadotrophic hypogonadism. Turner syndrome is a diagnostic one should not forget by its frequency. Treatment is hormonal replacement therapy and of the etiology. During the last decade, many genes have been identified and elucidated the etiological diagnosis of some hypogonadotrophic hypogonadism syndrome. Further studies are required in collaboration with molecular biologists to better understand the mechanism of hypothalamic pituitary gonadal axis abnormalities and of the neuroendocrine physiology of the onset of puberty.

[Early onset diabetes mellitus]. / Diabètes sucrés du très jeune enfant.

Neonatal diabetes mellitus is a rare condition (1/90,000 to 1/260,000 live births) defined as mild-to-severe hyperglycemia within the first year of life. Permanent neonatal diabetes mellitus requires lifelong therapy, whereas transient form resolves early in life but may relapse later on. Two main physiopathological mechanisms may explain this disease: ß cell functional impairment or absence (pancreas agenesis or ß cells destruction). The main genetic causes of ß cells impairment are 6q24 abnormalities and mutations in ABCC8 or KCNJ11 potassium channel (KATP channel) genes. Compared to the KATP subtype, the 6q24 subtype had specific features: developmental defects involving the heart, kidneys, or urinary tract, intrauterine growth restriction, and early diagnosis. Remission of neonatal diabetes mellitus occurred in 51% of probands at a median age of 17 weeks. Recurrence was common at pubertal age, with no difference between the 6q24 and KATP-channel groups (82% vs 86%, p=0.36, respectively). Patients with mutations in ABCC8 or KCNJ11 genes had developmental delay with or without epilepsy but also developmental coordination disorder (particularly visual-spatial dyspraxia) or attention deficits in all of those who underwent in-depth neuropsychomotor investigations.

Transcription factor gene MNX1 is a novel cause of permanent neonatal diabetes in a consanguineous family.

AIM: Permanent neonatal diabetes mellitus (PNDM) is a rare monogenic form of non-autoimmune diabetes. Genetic defects have been identified in∼60% of cases, with mutations in ABCC8, KCNJ11 and INS being the most frequent causes of PNDM. Recognition of genetic subtypes strongly impacts on both patients' care and family counseling. This study aimed to identify the genetic aetiology of PNDM in a diabetic girl born of consanguineous parents. METHODS: DNA samples from both the proband and her non-diabetic parents were analyzed for homozygosity mapping, using Illumina Infinium 660K SNP microarrays, focusing on the runs of homozygosity (ROHs) detected only in the patient. Standard Sanger sequencing of candidate genes (MNX1 and GATA6) present in the ROHs was subsequently performed, as well as expression analyses on human embryonic and adult pancreatic islet samples. RESULTS: A putative causal homozygous mutation in the transcription factor gene MNX1 (c.816C>A/p.Phe272Leu) was identified in the PNDM patient, who was clinically diagnosed as a typical case of PNDM with no developmental pancreatic defects or other clinical features. The probable deleterious mutation was located within the MNX1 homeodomain helix 2 that is highly conserved between species. In human embryonic pancreatic islet samples, it has been shown that MNX1 expression is significantly enriched in pancreatic epithelium compared with mesenchyme, suggesting a role for MNX1 in human pancreatic beta-cell development. CONCLUSION: This study found a new putative cause of PNDM in a consanguineous family. Replication in other cohorts would help to clarify the clinical spectrum of MNX1 mutations in PNDM patients.

Childhood craniopharyngioma: hypothalamus-sparing surgery decreases the risk of obesity.

CONTEXT: Craniopharyngioma is a brain tumor whose high local recurrence rate has for a long time led to a preference for extensive surgery. Limited surgery minimizing hypothalamic damage may decrease the severe obesity rate at the expense of the need for radiotherapy to complete the treatment. OBJECTIVE: We compared weight gain and local recurrence rates after extensive resection surgery (ERS) and hypothalamus-sparing surgery (HSS). DESIGN: Our observational study compared a historical cohort managed with ERS between 1985 and 2002 to a prospective cohort managed with HSS between 2002 and 2010. SETTING: The patients were treated in a pediatric teaching hospital in Paris, France. PATIENTS: Thirty-seven boys and 23 girls were managed with ERS (median age, 8 years); 38 boys and 27 girls were managed with HSS (median age, 9.3 years). MAIN OUTCOME MEASURES: Data were collected before and 6 months to 7 years after surgery. Body mass index (BMI) Z-score was used to assess obesity and the number of surgical procedures to assess local recurrence rate. RESULTS: Mean BMI Z-score before surgery was comparable in the 2 cohorts (0.756 after ERS vs 0.747 after HSS; P = .528). At any time after surgery, mean BMI Z-score was significantly lower after HSS (eg, 1.889 SD vs 2.915 SD, P = .004 at 1 year). At last follow-up, the HSS cohort had a significantly lower prevalence of severe obesity (28% vs 54%, P < .05) and higher prevalence of normal BMI (38% vs 17%, P < .01). Mean number of surgical procedures was not significantly different in the 2 cohorts. CONCLUSIONS: Hypothalamus-sparing surgery decreases the occurrence of severe obesity without increasing the local recurrence rate.