In vitro prediction of stop-codon suppression by intravenous gentamicin in patients with cystic fibrosis: a pilot study

BACKGROUND: Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which acts as a chloride channel activated by cyclic AMP (cAMP). The most frequent mutation found in 70% of CF patients is F508del, while premature stop mutations are found in about 10% of patients. In vitro aminoglycoside antibiotics (e.g. gentamicin) suppress nonsense mutations located in CFTR permitting translation to continue to the natural termination codon. Pharmacologic suppression of stop mutations within the CFTR may be of benefit to a significant number of patients. Our pilot study was conducted to determine whether intravenous gentamicin suppresses stop codons in CF patients and whether it has clinical benefits. METHODS: A dual gene reporter system was used to determine the gentamicin-induced readthrough level of the most frequent stop mutations within the CFTR in the French population. We investigated readthrough efficiency in response to 10 mg/kg once-daily intravenous gentamicin perfusions in patients with and without stop mutations. Respiratory function, sweat chloride concentration, nasal potential difference (NPD) and CFTR expression in nasal epithelial cells were measured at baseline and after 15 days of treatment. RESULTS: After in vitro gentamicin incubation, the readthrough efficiency for the Y122X mutation was at least five times higher than that for G542X, R1162X, and W1282X. In six of the nine patients with the Y122X mutation, CFTR immunodetection showed protein at the membrane of the nasal epithelial cells and the CFTR-dependent Cl(- )secretion in NPD measurements increased significantly. Respiratory status also improved in these patients, irrespective of the gentamicin sensitivity of the bacteria present in the sputum. Mean sweat chloride concentration decreased significantly and normalised in two patients. Clinical status, NPD and sweat Cl(- )values did not change in the Y122X patients with no protein expression, in patients with the other stop mutations investigated in vitro and those without stop mutations. CONCLUSION: Suppression of stop mutations in the CFTR gene with parenteral gentamicin can be predicted in vitro and is associated with clinical benefit and significant modification of the CFTR-mediated Cl(- )transport in nasal and sweat gland epithelium

Mitchell-Riley Syndrome : Improving Clinical Outcomes and Searching for Functional Impact of RFX-6 Mutations

Aims/HypothesisCaused by biallelic mutations of the gene encoding the transcription factor RFX6, the rare Mitchell-Riley syndrome (MRS) comprises neonatal diabetes, pancreatic hypoplasia, gallbladder agenesis or hypoplasia, duodenal atresia, and severe chronic diarrhea. So far, sixteen cases have been reported, all with a poor prognosis. This study discusses the multidisciplinary intensive clinical management of 4 new cases of MRS that survived over the first 2 years of life. Moreover, it demonstrates how the mutations impair the RFX6 function. MethodsClinical records were analyzed and described in detail. The functional impact of two RFX6(R181W) and RFX6(V506G) variants was assessed by measuring their ability to transactivate insulin transcription and genes that encode the L-type calcium channels required for normal pancreatic beta-cell function. ResultsAll four patients were small for gestational age (SGA) and prenatally diagnosed with duodenal atresia. They presented with neonatal diabetes early in life and were treated with intravenous insulin therapy before switching to subcutaneous insulin pump therapy. All patients faced recurrent hypoglycemic episodes, exacerbated when parenteral nutrition (PN) was disconnected. A sensor-augmented insulin pump therapy with a predictive low-glucose suspension system was installed with good results. One patient had a homozygous c.1517T>G (p.Val506Gly) mutation, two patients had a homozygous p.Arg181Trp mutation, and one patient presented with new compound heterozygosity. The RFX6(V506G) and RFX6(R181W) mutations failed to transactivate the expression of insulin and genes that encode L-type calcium channel subunits required for normal pancreatic beta-cell function. Conclusions/InterpretationMultidisciplinary and intensive disease management improved the clinical outcomes in four patients with MRS, including adjustment of parenteral/oral nutrition progression and advanced diabetes technologies. A better understanding of RFX6 function, in both intestine and pancreas cells, may break ground in new therapies, particularly regarding the use of drugs that modulate the enteroendocrine system.Peer reviewe

Diabète de la mucoviscidose (développement, mécanismes et conséquences)

Le diabète est fréquent et apparaît précocement chez les patients atteints de mucoviscidose. Il est associé à une détérioration de l'état nutritionnel et respiratoire. Objectifs : Mieux décrire l'histoire naturelle, les mécanismes et les conséquences du diabète chez les patients atteints de mucoviscidose, de l'enfance à l'âge adulte. Méthodes : Cinq cent dix sept hyperglycémies provoquées par voie orale (HGPO) ont été réalisées chez 237 enfants atteints de mucoviscidose (109 garçons, 128 filles ; 12 +- 5,6 ans), suivis entre 1988 et 2005 à l'hôpital Necker-Enfants Malades. Les données anthropométriques, biologiques (HBA1c, formule sanguine, vitesse de sédimentation), immunologiques (ICA) et génétiques (HLA, génotype CFTR), ainsi que les événements majeurs (transplantation, décès) ont été recueillis. La fonction b pancréatique a été estimée par des rapports insuline/glucose dérivés des données de l'HGPO (Aire sous la courbe, II30-0 /G30, HOMA-b). La sensibilité à l'insuline a été estimée en utilisant le modèle homéostatique HOMA-S. La progression des anomalies de la tolérance glucidique (intolérance au glucose, diabète à l'HGPO, traitement par insuline) a été évaluée par une analyse pour données censurées ; les taux de transplantations pulmonaires et de décès par une analyse de survie. Résultats : L'intolérance au glucose apparaît précocement (20% à l'âge de 10 ans), le risque cumulé augmente à 50% à l'âge de 15 ans, 75% à 20 ans et 82% à 30 ans. Le risque de diabète est > 20% à 15 ans, 45% à 20 ans et 70% à 30 ans ; celui de traitement par insuline est de 30% à 20 ans et 40% à 30 ans. Ces anomalies tendent à être plus précoces chez les filles. La précocité d'apparition des anomalies de la tolérance glucidique est associée à une mortalité accrue et à un taux plus important de transplantation pulmonaire. L'aire glycémique est inversement corrélée à l'indice de masse corporelle et à la taille. Le diabète est associé à une diminution de tous les indices de sécrétion d'insuline, l'intolérance au glucose à une diminution de la phase précoce de sécrétion d'insuline ( II30-0 /G30). On ne retrouve pas de corrélation avec l'indice de sensibilité à l'insuline HOMA-S, mais l'inflammation est associée à une diminution de la sensibilité à l'insuline et à une détérioration de la tolérance glucidique. Conclusion : Le diabète de la mucoviscidose est principalement dû à un déficit de sécrétion d'insuline. Il est extrêmement fréquent tôt dans la vie chez ces patients et est associé à une altération de l'état nutritionnel et à un taux accru d'insuffisance respiratoire terminale et de décèsPARIS6-Bibl.Pitié-Salpêtrie (751132101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Prise en charge de la grossesse au cours du diabète de type 1: Référentiel de la Société Francophone du Diabète (SFD) 2010

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Diagnostic Challenge in PLIN1-Associated Familial Partial Lipodystrophy

International audienc

Molecular and Cellular Bases of Lipodystrophy Syndromes

International audienceLipodystrophy syndromes are rare diseases originating from a generalized or partial loss of adipose tissue. Adipose tissue dysfunction results from heterogeneous genetic or acquired causes, but leads to similar metabolic complications with insulin resistance, diabetes, hypertriglyceridemia, nonalcoholic fatty liver disease, dysfunctions of the gonadotropic axis and endocrine defects of adipose tissue with leptin and adiponectin deficiency. Diagnosis, based on clinical and metabolic investigations, and on genetic analyses, is of major importance to adapt medical care and genetic counseling. Molecular and cellular bases of these syndromes involve, among others, altered adipocyte differentiation, structure and/or regulation of the adipocyte lipid droplet, and/or premature cellular senescence. Lipodystrophy syndromes frequently present as systemic diseases with multi-tissue involvement. After an update on the main molecular bases and clinical forms of lipodystrophy, we will focus on topics that have recently emerged in the field. We will discuss the links between lipodystrophy and premature ageing and/or immuno-inflammatory aggressions of adipose tissue, as well as the relationships between lipomatosis and lipodystrophy. Finally, the indications of substitutive therapy with metreleptin, an analog of leptin, which is approved in Europe and USA, will be discussed

Monogenic forms of lipodystrophic syndromes - diagnosis, detection, and practical management considerations from clinical cases

International audienceBACKGROUND: Lipodystrophic syndromes are rare diseases of genetic or acquired origin characterized by partial or generalized lack of body fat. Early detection and diagnosis are crucial to prevent and manage associated metabolic dysfunctions, i.e. insulin resistance, dyslipidemia, fatty liver, and diabetes, and to provide appropriate genetic counseling. By means of several representative case studies, this article illustrates the diagnostic and management challenges of lipodystrophic syndromes.REVIEW: Berardinelli-Seip congenital lipodystrophy (BSCL) is typically diagnosed at birth, or soon thereafter, with generalized lipoatrophy and hepatomegaly secondary to hepatic steatosis. Physicians must also consider this diagnosis in adults with atypical non-autoimmune diabetes, hypertriglyceridemia, and a lean and muscular phenotype. The BSCL1 subtype due to mutations in the AGPAT2 gene can have an unusual presentation, especially in neonates and infants. Particular attention should be paid to infants presenting failure to thrive who also have hepatomegaly and metabolic derangements. The BSCL2 sub-type due to mutations in the BSCL gene tends to be more severe than BSCL1, and is characterized by greater fat loss, mild intellectual disability, earlier onset of diabetes, and higher incidence of premature death. Effective management from an earlier age may moderate the natural disease course. Partial lipodystrophies may easily be confused with common central obesity and/or metabolic syndrome. In patients with unexplained pancreatitis and hypertriglyceridemia, lipodystrophies such as familial partial lipodystrophy type 2 (FPLD2; Dunnigan type, due to LMNA mutations) should be considered. Oral combined contraceptives, which can reveal the disease by inducing severe hypertriglyceridemia, are contraindicated. Endogenous estrogens may also lead to "unmasking" of the FPLD2 phenotype, which often appears at puberty, and is more severe in females than males.CONCLUSIONS: Diet and exercise, adapted to age and potential comorbidities, are essential prerequisites for therapeutic management of lipodystrophic syndromes. Metreleptin therapy can be useful to manage lipodystrophy-related metabolic complication

Outcomes of hybrid closed‐loop insulin delivery activated 24/7 versus evening and night in free‐living prepubertal children with type 1 diabetes: A multicentre, randomized clinical trial

International audienceAims: To assess the safety and efficacy of hybrid closed-loop (HCL) insulin delivery 24/7 vs. only evening and night (E/N), and on extended 24/7 use, in free-living children with T1D.Materials and methods: Pre-pubertal children (n = 122; 49F/73M, age: 8.6 ± 1.6, diabetes duration: 5.2 ± 2.3 years, insulin pump use: 4.6 ± 2.5 years, HbA1c: 7.7 ± 0.7%/61 ± 5 mmol/mol) from 4 centers were randomized for 24/7 vs. E/N activation of the Tandem Control-IQ system for 18 weeks. Afterwards, all children used the activated system 24/7 for 18 more weeks. Primary outcome was %time spent in 70-180 mg/dL glucose range (TIR).Results: HCL was active 94.1% and 51.1% of time on 24/7 and E/N modes, respectively. TIR from baseline increased more on 24/7 vs. E/N: 52.9 ± 9.5 to 67.3 ± 5.6 (+14.4%, 95CI: 12.4-16.7%) vs. 55.1 ± 10.8 to 64.7 ± 7.0 (+9.6%, 95CI: 7.4-11.6%), p = 0.001. Mean %time below range was similarly reduced from 4.2 and 4.6 to 2.7, and mean %time above range more on 24/7 mode: 41.9 to 30.0 (-11.9%, 95CI: 9.7-14.6%) vs. 39.8 to 32.6 (-7.2%, 95CI: 5.0-9.9%), p = 0.007. TIR increased through the whole range of baseline levels and always more with 24/7 use. The results were maintained during extension phase in those initially on 24/7 use and improved in those with initial E/N use up to those with 24/7 use. Neither ketoacidosis nor severe hypoglycemia occurred.Conclusions: Our study demonstrates the safety and efficacy of Tandem Control-IQ system in free-living children with T1D for both E/N and 24/7 use. 24/7 use shows better outcomes, sustained for up to 36 weeks with no safety issue. This article is protected by copyright. All rights reserved