The postinfectious irritable bowel syndrome (PI-IBS) suggests that impaired resolution of inflammation could cause IBS symptoms. The authors hypothesised that polymorphisms in genes whose expression ...were altered by gastroenteritis might be linked to IBS with diarrhoea (IBS-D) which closely resembles PI-IBS.
Part 1: 25 healthy volunteers (HVs), 21 patients 6 months after Campylobacter jejuni infection, 37 IBS-D and 19 IBS with constipation (IBS-C) underwent rectal biopsy for gene expression analysis and peripheral blood mononuclear cell cytokine production assessment. Part 2: Polymorphisms in genes whose expression was altered in Part 1 were assessed in 179 HV, 179 IBS-D, 122 IBS-C and 41 PI-IBS.
Part 1: Mucosal expression of seven genes was altered in IBS: CCL11, CCL13, Calpain 8 and TNFSF15 increased while NR1D1, GPR161 and GABRE decreased with similar patterns after infection with C jejuni. Part 2: The authors assessed 21 known single nucleotide polymorphisms (SNPs) in these seven genes and one SNP in each of the TNFα and IL-10 genes. Three out of five TNFSF15 SNPs (rs6478108, rs6478109 and rs7848647) showed reduced minor allele frequency (MAF) (0.28, 0.27 and 0.27) in subjects with IBS-D compared with HV (0.38, 0.36 and 0.37; p=0.007, 0.015 and 0.007, respectively) confirming others recent findings. The authors also replicated the previously reported association of the TNFα SNP rs1800629 with PI-IBS which showed an increase in the MAF at 0.30 versus 0.19 for HV (p=0.04).
IBS-D and PI-IBS patients are associated with TNFSF15 and TNFα genetic polymorphisms which also predispose to Crohn's disease suggesting possible common underlying pathogenesis.
Thiazide diuretics are among the most widely used treatments for hypertension, but thiazide-induced hyponatremia (TIH), a clinically significant adverse effect, is poorly understood. Here, we have ...studied the phenotypic and genetic characteristics of patients hospitalized with TIH. In a cohort of 109 TIH patients, those with severe TIH displayed an extended phenotype of intravascular volume expansion, increased free water reabsorption, urinary prostaglandin E2 excretion, and reduced excretion of serum chloride, magnesium, zinc, and antidiuretic hormone. GWAS in a separate cohort of 48 TIH patients and 2,922 controls from the 1958 British birth cohort identified an additional 14 regions associated with TIH. We identified a suggestive association with a variant in SLCO2A1, which encodes a prostaglandin transporter in the distal nephron. Resequencing of SLCO2A1 revealed a nonsynonymous variant, rs34550074 (p.A396T), and association with this SNP was replicated in a second cohort of TIH cases. TIH patients with the p.A396T variant demonstrated increased urinary excretion of prostaglandin E2 and metabolites. Moreover, the SLCO2A1 phospho-mimic p.A396E showed loss of transporter function in vitro. These findings indicate that the phenotype of TIH involves a more extensive metabolic derangement than previously recognized. We propose one mechanism underlying TIH development in a subgroup of patients in which SLCO2A1 regulation is altered.
Abstract The prostaglandin D2 (PGD2 ) receptor, CRTH2, plays a role in allergic airway inflammation. The efficacy of BI 671800, a CRTH2 antagonist, was assessed in 2 separate trials in patients with ...asthma, in either the absence or the presence of inhaled corticosteroid (ICS) therapy. In this study, BI 671800 (50, 200 or 400 mg) and fluticasone propionate (220 μg) all given twice daily (bid) were compared with bid placebo in symptomatic controller-naïve adults with asthma (Trial 1), and BI 671800 400 mg bid compared with montelukast 10 mg once daily (qd), and matching placebo bid, in patients with asthma receiving inhaled fluticasone (88 μg bid) (Trial 2). The primary endpoint in both trials was change from baseline in trough forced expiratory volume in 1 s (FEV1 ) percent predicted. After 6 weeks' treatment, adjusted mean treatment differences (SE) for the primary endpoint compared with placebo in Trial 1 were 3.08% (1.65%), 3.59% (1.60%) and 3.98% (1.64%) for BI 671800 50, 200 and 400 mg bid, respectively, and 8.62% (1.68%) for fluticasone 220 μg bid ( p = 0.0311, p = 0.0126, p = 0.0078 and p < 0.0001, respectively). In Trial 2, adjusted mean FEV1 (SE) treatment differences compared with placebo were 3.87% (1.49%) for BI 671800 400 mg bid and 2.37% (1.57%) for montelukast ( p = 0.0050 and p = 0.0657, respectively). These findings suggest that BI 671800 is associated with a small improvement in FEV1 in symptomatic controller-naïve asthma patients, and in patients on ICS.
Drawing on village-based data from Nepal, this paper explores the transferability of the Integrated Behavioural Model for Water, Sanitation and Hygiene (IBM-WASH) to the clean cooking sector and its ...potential to elucidate how barriers to improved cookstove adoption and sustained use intersect at different scales. The paper also explores the potential of IBM-WASH, behaviour settings theory and domestication analysis to collectively inform effective behaviour change techniques and interventions that promote both adoption and sustained use of health-promoting technologies. Information on cookstove use in the community since 2012 enables valuable insights to be gained on how kitchen settings and associated cooking behaviour were re-configured as homes and stoves were re-built following the April 2015 earthquake. The methodological approach comprised of semi-structured interviews, focus group discussions, direct observation and household surveys. The findings indicated that the IBM-WASH framework translated well to the improved cookstove sector, capturing key influences on clean cooking transitions across the model's three dimensions (context, psychosocial and technology) at all five levels. Understandings gained from utilising IBM-WASH were enhanced – especially at the individual and habitual levels – by domestication analysis and settings theory which elucidated how different cooking technologies were incorporated (or not) within physical structures, everyday lives and routine behaviour. The paper concludes that this combination of approaches has potential applicability for initiatives seeking to promote improved environmental health at community-wide scales.
•Transferability of IBM-WASH to the cookstove sector is explored for the first time.•Data from post-earthquake Nepal is used to test this transferability.•We demonstrate that the framework translates well to the cookstove sector.•Findings from IBM-WASH are enhanced by domestication analysis and settings theory.•This combination of approaches has broader applicability for health initiatives.
Studies report that the risks of significant neurologic complications (including stroke, cerebral abscess, and migraine) and hemorrhagic sequelae are high in patients with hereditary hemorrhagic ...telangiectasia (HHT), and that life expectancy in this cohort is reduced. However, most published cohorts derive from specialist centers, which may be susceptible to bias.
We used a population-based approach to estimate the risks of developing neurologic and hemorrhagic complications of HHT, the association of a diagnosis of HHT with common cardiovascular and malignant comorbidities, and also long-term survival of those with the disease.
From a UK primary care database of 3.5 million patients (The Health Improvement Network), we identified 675 cases with a diagnosis of HHT and compared them with 6,696 controls matched by age, sex, and primary care practice. Risks of stroke (odds ratio OR 1.8, 95% confidence interval CI 1.2-2.6), cerebral abscess (OR 30.0, CI 3.1-288), and migraine (OR 1.7, CI 1.3-2.2) were elevated over controls. Bleeding complications including epistaxis (OR 11.6, CI 9.1-14.7) and gastrointestinal hemorrhage (OR 6.1, CI 2.8-13.4) were more common in cases with HHT. Survival of cases with HHT was poorer than controls with a hazard ratio for death of 2.0 (CI 1.6-2.6) and a median age at death 3 years younger.
Patients with HHT are at substantially increased risk of serious neurologic and hemorrhagic complications of the disease. Because a diagnosis of HHT is associated with a significantly poorer survival compared with those who have no disease, evaluation of new strategies to improve clinical management is required.
The initial bronchoconstrictor response of the asthmatic airway depends on airway smooth muscle (ASM) contraction. Intracellular calcium is a key signaling molecule, mediating a number of responses, ...including proliferation, gene expression, and contraction of ASM. Ca(2+) influx through receptor-operated calcium (ROC) or store-operated calcium (SOC) channels is believed to mediate longer term signals. The mechanisms of SOC activation in ASM remain to be elucidated. Recent literature has identified the STIM and ORAI proteins as key signaling players in the activation of the SOC subtype; calcium release-activated channel current (I(CRAC)) in a number of inflammatory cell types. However, the role for these proteins in activation of SOC in smooth muscle is unclear. We have previously demonstrated a role for STIM1 in SOC channel activation in human ASM. The aim of this study was to investigate the expression and define the potential roles of the ORAI proteins in SOC-associated Ca(2+) influx in human ASM cells. Here we show that knockdown of ORAI1 by siRNA resulted in reduced thapsigargin- or cyclopiazonic acid (CPA)-induced Ca(2+) influx, without affecting Ca(2+) release from stores or basal levels. CPA-induced inward currents were also reduced in the ORAI1 knockdown cells. We propose that ORAI1 together with STIM1 are important contributors to SOC entry in ASM cells. These data extend the major tissue types in which these proteins appear to be major determinants of SOC influx, and suggest that modulation of these pathways may prove useful in the treatment of bronchoconstriction.
Extracellular ATP functions as a signaling messenger through its actions on purinergic receptors, and is known to be involved in numerous physiological and pathophysiological processes throughout the ...body, including in the lungs and airways. Consequently, purinergic receptors are considered to be promising therapeutic targets for many respiratory diseases, including asthma. This review explores how online bioinformatics resources combined with recently generated datasets can be utilized to investigate purinergic receptor gene expression in tissues and cell types of interest in respiratory disease to identify potential therapeutic targets, which can then be investigated further. These approaches show that different purinergic receptors are expressed at different levels in lung tissue, and that purinergic receptors tend to be expressed at higher levels in immune cells and at more moderate levels in airway structural cells. Notably, P2RX1, P2RX4, P2RX7, P2RY1, P2RY11, and P2RY14 were revealed as the most highly expressed purinergic receptors in lung tissue, therefore suggesting that these receptors have good potential as therapeutic targets for asthma and other respiratory diseases.
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide; smoking is the main risk factor for COPD, but genetic factors are also relevant contributors. Genome-wide ...association studies (GWAS) of the lung function measures used in the diagnosis of COPD have identified a number of loci, however association signals are often broad and collectively these loci only explain a small proportion of the heritability. In order to examine the association with COPD risk of genetic variants down to low allele frequencies, to aid fine-mapping of association signals and to explain more of the missing heritability, we undertook a targeted sequencing study in 300 COPD cases and 300 smoking controls for 26 loci previously reported to be associated with lung function. We used a pooled sequencing approach, with 12 pools of 25 individuals each, enabling high depth (30x) coverage per sample to be achieved. This pooled design maximised sample size and therefore power, but led to challenges during variant-calling since sequencing error rates and minor allele frequencies for rare variants can be very similar. For this reason we employed a rigorous quality control pipeline for variant detection which included the use of 3 independent calling algorithms. In order to avoid false positive associations we also developed tests to detect variants with potential batch effects and removed them before undertaking association testing. We tested for the effects of single variants and the combined effect of rare variants within a locus. We followed up the top signals with data available (only 67% of collapsing methods signals) in 4,249 COPD cases and 11,916 smoking controls from UK Biobank. We provide suggestive evidence for the combined effect of rare variants on COPD risk in TNXB and in sliding windows within MECOM and upstream of HHIP. These findings can lead to an improved understanding of the molecular pathways involved in the development of COPD.
Some people have characteristics of both asthma and COPD (asthma-COPD overlap), and evidence suggests they experience worse outcomes than those with either condition alone.
What is the genetic ...architecture of asthma-COPD overlap, and do the determinants of risk for asthma-COPD overlap differ from those for COPD or asthma?
We conducted a genome-wide association study in 8,068 asthma-COPD overlap case subjects and 40,360 control subjects without asthma or COPD of European ancestry in UK Biobank (stage 1). We followed up promising signals (P < 5 × 10–6) that remained associated in analyses comparing (1) asthma-COPD overlap vs asthma-only control subjects, and (2) asthma-COPD overlap vs COPD-only control subjects. These variants were analyzed in 12 independent cohorts (stage 2).
We selected 31 independent variants for further investigation in stage 2, and discovered eight novel signals (P < 5 × 10–8) for asthma-COPD overlap (meta-analysis of stage 1 and 2 studies). These signals suggest a spectrum of shared genetic influences, some predominantly influencing asthma (FAM105A, GLB1, PHB, TSLP), others predominantly influencing fixed airflow obstruction (IL17RD, C5orf56, HLA-DQB1). One intergenic signal on chromosome 5 had not been previously associated with asthma, COPD, or lung function. Subgroup analyses suggested that associations at these eight signals were not driven by smoking or age at asthma diagnosis, and in phenome-wide scans, eosinophil counts, atopy, and asthma traits were prominent.
We identified eight signals for asthma-COPD overlap, which may represent loci that predispose to type 2 inflammation, and serious long-term consequences of asthma.
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Chronic obstructive pulmonary disease (COPD) is a leading cause of global morbidity and mortality and, whilst smoking remains the single most important risk factor, COPD risk is heritable. Of 26 ...independent genomic regions showing association with lung function in genome-wide association studies, eleven have been reported to show association with airflow obstruction. Although the main risk factor for COPD is smoking, some individuals are observed to have a high forced expired volume in 1 second (FEV1) despite many years of heavy smoking. We hypothesised that these "resistant smokers" may harbour variants which protect against lung function decline caused by smoking and provide insight into the genetic determinants of lung health. We undertook whole exome re-sequencing of 100 heavy smokers who had healthy lung function given their age, sex, height and smoking history and applied three complementary approaches to explore the genetic architecture of smoking resistance. Firstly, we identified novel functional variants in the "resistant smokers" and looked for enrichment of these novel variants within biological pathways. Secondly, we undertook association testing of all exonic variants individually with two independent control sets. Thirdly, we undertook gene-based association testing of all exonic variants. Our strongest signal of association with smoking resistance for a non-synonymous SNP was for rs10859974 (P = 2.34 × 10(-4)) in CCDC38, a gene which has previously been reported to show association with FEV1/FVC, and we demonstrate moderate expression of CCDC38 in bronchial epithelial cells. We identified an enrichment of novel putatively functional variants in genes related to cilia structure and function in resistant smokers. Ciliary function abnormalities are known to be associated with both smoking and reduced mucociliary clearance in patients with COPD. We suggest that genetic influences on the development or function of cilia in the bronchial epithelium may affect growth of cilia or the extent of damage caused by tobacco smoke.
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