A loss-of-function mutation in KCNJ11 causing sulfonylurea-sensitive diabetes in early adult life.

AIMS/HYPOTHESIS: The ATP-sensitive potassium (KATP) channel couples beta cell electrical activity to glucose-stimulated insulin secretion. Loss-of-function mutations in either the pore-forming (inwardly rectifying potassium channel 6.2 [Kir6.2], encoded by KCNJ11) or regulatory (sulfonylurea receptor 1, encoded by ABCC8) subunits result in congenital hyperinsulinism, whereas gain-of-function mutations cause neonatal diabetes. Here, we report a novel loss-of-function mutation (Ser118Leu) in the pore helix of Kir6.2 paradoxically associated with sulfonylurea-sensitive diabetes that presents in early adult life. METHODS: A 31-year-old woman was diagnosed with mild hyperglycaemia during an employee screen. After three pregnancies, during which she was diagnosed with gestational diabetes, the patient continued to show elevated blood glucose and was treated with glibenclamide (known as glyburide in the USA and Canada) and metformin. Genetic testing identified a heterozygous mutation (S118L) in the KCNJ11 gene. Neither parent was known to have diabetes. We investigated the functional properties and membrane trafficking of mutant and wild-type KATP channels in Xenopus oocytes and in HEK-293T cells, using patch-clamp, two-electrode voltage-clamp and surface expression assays. RESULTS: Functional analysis showed no changes in the ATP sensitivity or metabolic regulation of the mutant channel. However, the Kir6.2-S118L mutation impaired surface expression of the KATP channel by 40%, categorising this as a loss-of-function mutation. CONCLUSIONS/INTERPRETATION: Our data support the increasing evidence that individuals with mild loss-of-function KATP channel mutations may develop insulin deficiency in early adulthood and even frank diabetes in middle age. In this case, the patient may have had hyperinsulinism that escaped detection in early life. Our results support the importance of functional analysis of KATP channel mutations in cases of atypical diabetes.

Objective and Subjective Sleep Patterns in Adults With Maturity-Onset Diabetes of the Young (MODY).

OBJECTIVE: To examine sleep patterns in adults with maturity-onset diabetes of the young (MODY). RESEARCH DESIGN AND METHODS: Adults with glucokinase (GCK)-MODY and transcription factor (TF)-related MODY (HNF1A, HNF1B, HNF4A) were recruited (n = 24; age 46.0 years, 79% women, BMI 24.7 kg/m2) from The University of Chicago's Monogenic Diabetes Registry. Sleep patterns were assessed by 2-week wrist actigraphy (total 315 nights), one night of a home sleep apnea test, and validated surveys. RESULTS: Overall, compared with established criteria, 29% of participants had sleep latency ≥15 min, 38% had sleep efficiency ≤85%, 46% had wake after sleep onset >40 min, all indicating poor objective sleep quality. Among all participants, 54% had a sleep duration below the recommended minimum of 7 h, 88% reported poor sleep quality, 58% had obstructive sleep apnea, and 71% reported insomnia. Compared with GCK-MODY, participants with TF-related MODY had poorer objective sleep quality and increased night-to-night variability in sleep patterns. CONCLUSIONS: Sleep disturbances appear to be common in adults with MODY despite absent traditional risk factors for sleep disorders. Future research investigating the sleep-diabetes relationship is warranted in this population.

Growth After Menarche in Pediatric Inflammatory Bowel Disease.

OBJECTIVES: Growth impairment in pediatric patients with pediatric onset inflammatory bowel disease (IBD) is multifactorial. Reports on the effect of age at menarche on adult stature in this population are limited. This study investigated the impact of age at menarche, disease-associated factors, and mid-parental height on growth from menarche to final height (FHt) in pediatric patients with Crohn disease (CD) and ulcerative colitis (UC) and IBD unclassified (IBD-U). METHODS: Subjects were enrolled from a prospectively maintained pediatric IBD database when IBD preceded menarche and dates of menarche and FHt measurements were recorded. RESULTS: One hundred forty-six patients: CD 112 and UC 30/IBD-U 4. Mean age (years) at diagnosis (10.9 vs 10.1), menarche (14.4 vs 14.0), and FHt (19.6 vs 19.7). CD and UC/IBD-U patients showed significant association between Chronological age (CA) at menarche and FHt (cm, P < 0.001) but not FHt z score (FHt-Z) < -1.0 (P = 0.42). FHt-Z < -2.0 occurred in only 5 patients. Growth impairment (FHt-Z < -1.0) was associated with surgery before menarche (P = 0.03), jejunal disease (P = 0.003), low mid-parental height z score (MPH-Z) (P < 0.001), hospitalization for CD (P = 0.03) but not UC, recurrent corticosteroid, or anti-tumor necrosis factor alpha (anti-TNFα) therapy. CONCLUSIONS: Early age of menarche was associated with greater potential for linear growth to FHt but not FHt-Z (P < 0.05). Surgery before menarche, jejunal disease, hospitalization for CD, low MPH, and weight z score were associated with FHt-Z < -1.0.

Novel KDM6A Kabuki Syndrome Mutation With Hyperinsulinemic Hypoglycemia and Pulmonary Hypertension Requiring ECMO.

Kabuki syndrome (KS) is a multisystem disorder estimated to occur in 1:32 000 newborns. Pathogenic mutations cause the majority but not all cases of KS in either KMT2D or KDM6A. KS can be suspected by phenotypic features, including infantile hypotonia, developmental delay, dysmorphic features, congenital heart defects, and others. Still, many of these features are not readily apparent in a newborn. Although neonatal hypoglycemia has been reported in 8% to 10% of patients with KS, the incidence and severity of hyperinsulinemic hypoglycemia (HH) is not well-studied. We present a full-term female infant with HH who was responsive to low-dose diazoxide. At 3 months of age, she was admitted for septic shock, worsening respiratory status, and severe pulmonary hypertension, requiring extracorporeal membrane oxygenation support. Her neonatal history was notable for hypotonia, dysphagia with aspiration requiring gastrostomy tube placement, and a cardiac defect-hypoplastic aortic arch requiring aortic arch repair. She has characteristic facial features, including prominent eyelashes, long palpebral fissures, and a short nasal columella. Next-generation sequencing for HH revealed a de novo likely pathogenic missense variant in KDM6A gene: c.3479G > T, p.Gly1160Val that was absent from population databases. Genetic testing for causes of HH should include testing of the KS genes KMT2D and KDM6A. Early detection of the underlying genetic defect will help guide management as all reported HH cases associated with KS have been responsive to diazoxide. Affected infants with underlying cardiac conditions may be at higher risk of serious respiratory complications such as pulmonary hypertension.

Dysbiosis of Gram-negative gut microbiota and the associated serum lipopolysaccharide exacerbates inflammation in type 2 diabetic patients with chronic kidney disease.

Lipopolysaccharide (LPS), a potent endotoxin present in the outer membrane of Gram-negative bacteria, causes chronic immune responses associated with inflammation. In the present study, the association between LPS and the dysbiosis of Gram-negative bacteria in the gut microbiome was determined in patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (T2DM-CKD; stages 4 and 5, not on dialysis) compared with healthy individuals. Microbiome diversity was analyzed in patients with T2DM-CKD and healthy controls by sequencing the hypervariable sub-regions of the 16S ribosomal RNA gene from stool samples. Serum samples were assayed by ELISA for LPS, C-reactive protein (CRP), tumor necrosis factor-α (TNFα), interleukin-6 (IL6) and endothelin-1. A total of four gut Gram-negative phyla (Bacteroidetes, Proteobacteria, Fusobacteria and Verrucomicrobia) were identified in the gut microbiome of the T2DM-CKD and control groups. Proteobacteria, Verrucomicrobia and Fusobacteria exhibited significantly increased relative abundance in patients with T2DM-CKD when compared with controls (P<0.05). The levels of serum LPS were significantly increased in patients with T2DM-CKD compared with controls (P<0.05). Elevated serum LPS was significantly correlated with increased levels of TNFα, IL6 and CRP. The dysbiosis of Gram-negative bacteria in the gut microbiome of patients with T2DM-CKD may contribute to the elevated serum levels of LPS and the consequential effects on the inflammatory biomarkers in these patients. The association between the dysbiosis of Gram-negative bacteria in the gut microbiome of patients with T2DM-CKD, increased LPS levels and the effects on inflammatory biomarkers may provide insight into potential diagnostic and therapeutic approaches in the treatment of T2DM-CKD.

Gut Microbiota-Dependent Trimethylamine-N-oxide and Serum Biomarkers in Patients with T2DM and Advanced CKD.

Trimethylamine-N-oxide (TMAO) is a product of dietary, gut microbiome, and tissues metabolism. Elevated blood TMAO levels are associated with heart attack, stroke and chronic kidney disease (CKD). The purpose of our study was to investigate the gut microbiota associated with trimethylamine (TMA) production, the precursor of TMAO, and the serum levels of TMAO and inflammatory biomarkers associated with type 2 diabetes mellitus (T2DM) and CKD. Twenty adults with T2DM and advanced CKD and 20 healthy adults participated in the study. Analyses included anthropometric and metabolic parameters, characterization of TMA producing gut microbiota, and concentrations of TMAO, lipopolysaccharides (LPS) endotoxin, zonulin (Zo) gut permeability marker, and serum inflammatory and endothelial dysfunction biomarkers. Diversity of the gut microbiota was identified by amplification of V3-V4 regions of the 16S ribosomal RNA genes and DNA sequencing. TMAO was quantified by Mass Spectrometry and serum biomarkers by ELISA. The significance of measurements justified by statistical analysis. The gut microbiome in T2DM-CKD patients exhibited a higher incidence of TMA-producing bacteria than control, p < 0.05. The serum levels of TMAO in T2DM-CKD patients were significantly higher than controls, p < 0.05. TMAO showed a positive correlation with Zo and LPS, inflammatory and endothelial dysfunction biomarkers. A positive correlation was observed between Zo and LPS in T2DM-CKD subjects. An increased abundance of TMA-producing bacteria in the gut microbiota of T2DM-CKD patients together with excessive TMAO and increased gut permeability might impact their risk for cardiovascular disease through elevation of chronic inflammation and endothelial dysfunction.

Resolvin D1 and lipoxin A4 improve alveolarization and normalize septal wall thickness in a neonatal murine model of hyperoxia-induced lung injury.

BACKGROUND: The critical fatty acids Docosahexaenoic Acid (DHA) and Arachidonic Acid (AA) decline in preterm infants within the first postnatal week and are associated with neonatal morbidities, including bronchopulmonary dysplasia (BPD). DHA and AA are precursors to downstream metabolites that terminate the inflammatory response. We hypothesized that treatment with Resolvin D1 and/or Lipoxin A4 would prevent lung injury in a murine model of BPD. OBJECTIVE: To determine the effect of Resolvin D1 and/or Lipoxin A4 on hyperoxia-induced lung injury. METHODS: C57/BL6 pups were randomized at birth to Room Air, Hyperoxia (>90% oxygen), Hyperoxia + Resolvin D1, Hyperoxia + Lipoxin A4, or Hyperoxia + Resolvin D1/Lipoxin A4. Resolvin D1 and/or Lipoxin A4 (2 ng/g) were given IP on days 0, 3, 6, and 9. On day 10, mice were sacrificed and lungs collected for morphometric analyses including Mean Linear Intercept (MLI), Radial Alveolar Count (RAC), and Septal Thickness (ST); RT-PCR analyses of biomarkers of lung development and inflammation; and ELISA for TGFß1 and TGFß2. RESULT: The increased ST observed with hyperoxia exposure was normalized by both Resolvin D1 and Lipoxin A4; while, hyperoxia-induced alveolar simplification was attenuated by Lipoxin A4. Relative to hyperoxia, Resolvin D1 reduced the gene expression of CXCL2 (2.9 fold), TIMP1 (6.7 fold), and PPARγ (4.8 fold). Treatment with Lipoxin A4 also led to a reduction of CXCL2 (2.4 fold) while selectively increasing TGFß2 (2.1 fold) and Smad3 (1.58 fold). CONCLUSION: The histologic and biochemical changes seen in hyperoxia-induced lung injury in this murine model can be reversed by the addition of DHA and AA fatty acid downstream metabolites that terminate the inflammatory pathways and modulate growth factors. These fatty acids or their metabolites may be novel therapies to prevent or treat lung injury in preterm infants.