Tidal breathing, and especially deep breathing, is known to antagonise bronchoconstriction caused by airway smooth muscle (ASM) contraction; however, this bronchoprotective effect of breathing is impaired in asthma. Force fluctuations applied to contracted ASM in vitro cause it to relengthen, force-fluctuation-induced relengthening (FFIR). Given that breathing generates similar force fluctuations in ASM, FFIR represents a likely mechanism by which breathing antagonises bronchoconstriction. Thus it is of considerable interest to understand what modulates FFIR, and how ASM might be manipulated to exploit this phenomenon. It was demonstrated previously that p38 mitogen-activated protein kinase (MAPK) signalling regulates FFIR in ASM strips. Here, it was hypothesised that the MAPK kinase (MEK) signalling pathway also modulates FFIR.
In order to test this hypothesis, changes in FFIR were measured in ASM treated with the MEK inhibitor, U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene).
Increasing concentrations of U0126 caused greater FFIR. U0126 reduced extracellular signal-regulated kinase 1/2 phosphorylation without affecting isotonic shortening or 20-kDa myosin light chain and p38 MAPK phosphorylation. However, increasing concentrations of U0126 progressively blunted phosphorylation of high-molecular-weight caldesmon (h-caldesmon), a downstream target of MEK. Thus changes in FFIR exhibited significant negative correlation with h-caldesmon phosphorylation.
The present data demonstrate that FFIR is regulated through MEK signalling, and suggest that the role of MEK is mediated, in part, through caldesmon.
Airway smooth muscle; asthma; bronchoconstriction; smooth muscle mechanics; tidal breathing
Caveolae, plasma membrane invaginations with constitutive caveolin proteins, harbour proteins involved in intracellular calcium ([Ca2+]i) regulation. In human airway smooth muscle (ASM), store-operated Ca2+ entry (SOCE) is a key component of [Ca2+]i regulation, and contributes to increased [Ca2+]i in inflammation. SOCE involves proteins Orai1 and stromal interaction molecule (STIM)1. We investigated the link between caveolae, SOCE and inflammation in ASM.
[Ca2+]i was measured in human ASM cells using fura-2. Small interference RNA (siRNA) or overexpression vectors were used to alter expression of caveolin-1 (Cav-1), Orai1 or STIM1. Tumour necrosis factor (TNF)-α was used as a representative pro-inflammatory cytokine.
TNF-α increased SOCE following sarcoplasmic reticulum Ca2+ depletion, and increased whole-cell and caveolar Orai1 (but only intracellular STIM1). Cav-1 siRNA decreased caveolar and whole-cell Orai1 (but not STIM1) expression, and blunted SOCE, even in the presence of TNF-α. STIM1 overexpression substantially enhanced SOCE: an effect only partially reversed by Cav-1 siRNA. In contrast, Orai1 siRNA substantially blunted SOCE even in the presence of TNF-α. Cav-1 overexpression significantly increased Orai1 expression and SOCE, especially in the presence of TNF-α.
These results demonstrate that caveolar expression and regulation of proteins such as Orai1 are important for [Ca2+]i regulation in human ASM cells and its modulation during inflammation.
Asthma; caveolae; cytokine; inflammation; Orai1; stromal interaction molecule 1
Ciliary beating of airway epithelial cells drives the removal of mucus and particles from the airways. Mucociliary transport and possibly airway epithelial development are governed by muscarinic acetylcholine receptors but the precise roles of the subtypes involved are unknown.
This issue was addressed by determining cilia-driven particle transport, ciliary beat frequency, and the composition and ultrastructural morphology of the tracheal epithelium in M1–M5 muscarinic receptor gene-deficient mice.
Knockout of M3 muscarinic receptors prevented an increase in particle transport speed and ciliary beat frequency in response to muscarine. Furthermore, the ATP response after application of muscarine was blunted. Pretreatment with atropine before application of muscarine restored the response to ATP. Additional knockout of the M2 receptor in these mice partially restored the muscarine effect most likely through the M1 receptor and normalized the ATP response. M1, M4, and M5 receptor deficient mice exhibited normal responses to muscarine. None of the investigated mutant mouse strains had any impairment of epithelial cellular structure or composition.
In conclusion, M3 receptors stimulate whereas M2 receptors inhibit cilia-driven particle transport. The M1 receptor increases cilia-driven particle transport if the M3 and M2 receptor are missing. None of the receptors is necessary for epithelial development.
cholinergic signal transduction; epithelial development; knockout mice; mucociliary clearance
Protective effects of prostacyclin and its stable analog Iloprost are mediated by elevation of intracellular cAMP leading to enhancement of peripheral actin cytoskeleton and cell-cell adhesive structures. This study tested hypothesis that iloprost may exhibit protective effects against lung injury and endothelial barrier dysfunction induced by bacterial wall lypopolysacharide (LPS).
Endothelial barrier dysfunction was assessed by measurements of transendothelial permeability, morphologically, and analysis of LPS-activated inflammatory signaling. In vivo, C57BL/6J mice were challenged with LPS with or without iloprost or 8-bromoadenosine-3′,5′-cyclic monophosphate (Br-cAMP) treatment. Lung injury was monitored by measurements of bronchoalveolar lavage protein content, cell count, and Evans blue extravasation.
Iloprost and Br-cAMP attenuated disruption of endothelial monolayer and suppressed activation of p38 mitogen activated protein (MAP) kinase, NFκB pathway, Rho signaling, ICAM1 expression, and neutrophil migration after LPS challenge. In vivo, iloprost was effective against LPS-induced protein and neutrophil accumulation in bronchoalveolar lavage fluid and reduced myeloperoxidase activation, ICAM-1 expression, and Evans blue extravasation in the lungs. Inhibition of Rac activity abolished barrier protective and anti-inflammatory effects of iloprost and Br-cAMP.
Iloprost-induced elevation of intracellular cAMP triggers Rac signaling, which attenuates LPS-induced NFκB and p38 MAPK inflammatory pathways and Rho-dependent mechanism of endothelial permeability.
cytoskeleton; endothelium; permeability; lung; inflammation
Rituximab, a monoclonal antibody directed against the B-lymphocyte antigen CD20, has shown promise in several autoimmune disorders. Pulmonary Alveolar Proteinosis (PAP) is an autoimmune disorder characterized by autoantibodies to Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF).
An open label proof-of-concept Phase II clinical trial was conducted in 10 PAP patients. Intervention consisted of two intravenous infusions of rituximab (1000mg), fifteen days apart. Bronchoalveolar lavage (BAL) and peripheral blood samples were collected.
The primary outcome was improvement in arterial blood oxygenation. Both PaO2 and A-a gradient on room air improved in 7/9 patients completing the study. Lung function and HRCT scans, secondary outcomes, also improved. Peripheral blood CD19+ B-lymphocytes decreased from 15±2% to <0.05% (n=10) fifteen days post therapy. This decrease persisted for 3 months in all patients; at six months CD19+ were detected in 4/7 patients (mean 5±2). Total anti-GM-CSF IgG levels from baseline to 6 months were decreased in BAL fluids (n=8), but unchanged in sera (n=9).
In this PAP cohort, (1) rituximab was well-tolerated and effectively ameliorated lung disease; (2) reduction in anti-GM-CSF IgG levels in the lung correlated with disease changes suggesting that disease pathogenesis is related to autoantibody levels in the target organ.
PAP; rituximab; B Cells; BAL
We determined lung bioavailability of a fluticasone propionate (FP) pressurised metred-dose inhaler (Flovent® HFA; GlaxoSmithKline, Research Triangle Park, NC, USA) administered via AeroChamber Plus® (Monaghan Medical, Plattsburgh, NY, USA) with Facemask and Babyhaler® (GlaxoSmithKline) valved holding chambers (VHCs) using a population pharmacokinetic approach.
Children from 1 to <4 yrs of age with stable asthma but a clinical need for inhaled corticosteroid therapy were administered 88 µg FP hydrofluoroalkane (2 × 44 µg) twice daily delivered through the two devices in an open-label, randomised crossover manner for 8 days each. Patients were randomised to one of three sparse sampling schedules for blood collection throughout the 12-h dosing interval on the 8th day of each treatment for pharmacokinetic analysis. The area under the FP plasma concentration–time curve (AUC) was determined for each regimen.
17 children completed the study. The population mean AUC following FP with AeroChamber Plus® with Facemask was 97.45 pg·h·mL−1 (95% CI 85.49–113.32 pg·h·mL−1) and with Babyhaler® was 51.55 pg·h·mL−1 (95% CI 34.45–64.46 pg·h·mL−1). The relative bioavailability (Babyhaler®/AeroChamber Plus®) was 0.53 (95% CI 0.30–0.75).
Clinically significant differences in lung bioavailability were observed between the devices. VHCs are not interchangeable, as differences in drug delivery to the lung may occur. A population pharmacokinetic approach can be used to determine lung bioavailability of FP.
Asthma; inhaled corticosteroid; lung bioavailability; preschool children; valved holding chamber
The calibre of the upper airway is thought to be dependant upon its passive anatomy/collapsibility and the activation of pharyngeal dilator muscles. During awake periods, the more collapsible upper airway in obstructive sleep apnoea (OSA) increases the dilator muscle activity through a negative-pressure reflex.
A direct correlation between the critical closing pressure (Pcrit), as a measure of anatomy/collapsability and electromyogram (EMG) activity of genioglossus EMG (GG-EMG) and tensor palatini EMG (TP-EMG), was hypothesised. The relationship between these indices and pharyngeal resistance (Rphar) was also examined.
The study involved eight males with a mean age of 48 (interquartile range 46–52) yrs with OSA, and an apnoea/hypopnoea index of 75 (65–101)·hr−1 on two nights breathing normally and on nasal continuous positive airway pressure (nCPAP). The Pcrit was measured during nonrapid eye movement sleep on nCPAP using brief, incremental reductions in mask pressure. GG-EMG and TP-EMG were measured breath-by-breath, awake, during sleep onset and on nCPAP. Rphar was measured using airway pressures and flow.
Wakeful GG-EMG, early sleep TP-EMG and the sleep decrement in TP-EMG were directly related to Pcrit. Muscle activation was negatively correlated with Rphar for TP-EMG awake and GGEMG early in sleep.
In conclusion these results confirm that dilator muscle activation is directly related to airway narrowing and reduces resistance across patients with obstructive sleep apnoea.
Airway mechanics; airways resistance; muscle function; obstructive sleep apnoea; pharynx
The A/H1N1 influenza strain isolated in Mexico in 2009 caused severe pulmonary illness in a small number of exposed individuals. Our objective was to determine the influence of genetic factors on their susceptibility.
We carried out a case–control association study genotyping 91 patients with confirmed severe pneumonia from A/H1N1 infection and 98 exposed but asymptomatic household contacts, using the HumanCVD BeadChip (Illumina, San Diego, CA, USA).
Four risk single-nucleotide polymorphisms were significantly (p<0.0001) associated with severe pneumonia: rs1801274 (Fc fragment of immunoglobulin G, low-affinity IIA, receptor (FCGR2A) gene, chromosome 1; OR 2.68, 95% CI 1.69–4.25); rs9856661 (gene unknown, chromosome 3; OR 2.62, 95% CI 1.64–4.18); rs8070740 (RPA interacting protein (RPAIN) gene, chromosome 17; OR 2.67, 95% CI 1.63–4.39); and rs3786054 (complement component 1, q subcomponent binding protein (C1QBP) gene, chromosome 17; OR 3.13, 95% CI 1.89–5.17). All SNP associations remained significant after adjustment for sex and comorbidities. The SNPs on chromosome 17 were in linkage disequilibrium.
These findings revealed that gene polymorphisms located in chromosomes 1 and 17 might influence susceptibility to development of severe pneumonia in A/H1N1 infection. Two of these SNPs are mapped within genes (FCGR2A, C1QBP) involved in the handling of immune complexes and complement activation, respectively, suggesting that these genes may confer risk due to increased activation of host immunity.
A/H1N1; genetic susceptibility; influenza; Mexicans; single-nucleotide polymorphisms; viral pneumonia
Multidrug-resistant tuberculosis (MDR-TB) is a major concern in countries of the former Soviet Union. The reported risk of resistance among TB cases in the Republic of Moldova is among the highest in the world. We aimed to produce high-resolution spatial maps of MDR-TB risk and burden in this setting.
We analyzed national TB surveillance data collected between 2007 and 2010 in Moldova. High drug susceptibility testing coverage and detailed location data permitted identification of sub-regional areas of higher MDR-TB risk. We investigated whether the distribution of cases with MDR-TB risk factors could explain this observed spatial variation in MDR-TB.
3,447 MDR-TB cases were notified during this period; 24% of new and 62% of previously treated patients had MDR-TB. Nationally, the estimated annual MDR-TB incidence was 54 cases/100,000 persons and >1,000 cases/100,000 persons within penitentiaries. We identified substantial geographic variation in MDR-TB burden and hotspots of MDR-TB. Locations with a higher percentage of previously incarcerated TB cases were at greater risk of being MDR-TB hotspots.
Spatial analyses revealed striking geographic heterogeneity of MDR-TB. Methods to identify locations of high MDR-TB risk and burden should allow for better resource allocation and more appropriate targeting of studies to understand local mechanisms driving resistance.
antibiotic resistance; geographic heterogeneity; mapping; Moldova; spatial epidemiology
The effects of cannabis on lung function remain unclear and may be different from those of tobacco. We compared the associations between use of these substances and lung function in a population-based cohort (n=1,037).
Cannabis and tobacco use were reported at ages 18, 21, 26 and 32 yrs. Spirometry, plethysmography and carbon monoxide transfer factor were measured at 32 yrs. Associations between lung function and exposure to each substance were adjusted for exposure to the other substance.
Cumulative cannabis use was associated with higher forced vital capacity, total lung capacity, functional residual capacity and residual volume. Cannabis was also associated with higher airway resistance but not with forced expiratory volume in 1 s, forced expiratory ratio or transfer factor. These findings were similar among those who did not smoke tobacco. In contrast, tobacco use was associated with lower forced expiratory volume in 1 s, lower forced expiratory ratio, lower transfer factor and higher static lung volumes, but not with airway resistance.
Cannabis appears to have different effects on lung function from those of tobacco. Cannabis use was associated with higher lung volumes, suggesting hyperinflation and increased large-airways resistance, but there was little evidence for airflow obstruction or impairment of gas transfer.
Cannabis; cohort study; marijuana; respiratory function; smoking; tobacco
No large study has described the seasonal variation in asthma attacks in
population-based asthmatics in whom sensitisation to allergen has been
2637 young adults with asthma living in 15 countries reported the months in which
they usually had attacks of asthma and had skin-prick tests performed.
Differences in seasonal patterns by sensitisation status were assessed using
generalised estimating equations.
Most young adults with asthma reported periods of the year when their asthma
attacks were more common (range: 47% in Sweden to 86% in
Spain). Seasonal variation in asthma was not modified by sensitisation to
house dust mite or cat allergens. Asthmatics sensitised to grass, birch and
Alternaria allergens had different seasonal patterns to
those not sensitised to each allergen, with some geographical variation. In
southern Europe, those sensitised to grass allergens were more likely to report
attacks occurred in spring or summer than in winter (OR March/April 2.60,
95% CI 1.70–3.97; OR May/June 4.43, 95% CI
2.34–8.39) and smaller later peaks were observed in northern Europe
(OR May/June 1.25, 95% CI 0.60–2.64; OR July/August 1.66,
95% CI 0.89–3.10). Asthmatics reporting hay fever but who were
not sensitised to grass showed no seasonal variations.
Seasonal variations in asthma attacks in young adults are common and are
different depending on sensitisation to outdoor, but not indoor, allergens.
Seasonal variation in asthma attacks is associated with sensitisation to
pollens and moulds, but not indoor allergens
Derive continuous prediction equations and their lower limits of normal for spirometric indices, which are applicable globally.
Over 160,000 data points from 72 centres in 33 countries were shared with the European Respiratory Society Global Lung Function Initiative. Eliminating data that could not be used (mostly missing ethnic group, some outliers) left 97,759 records of healthy nonsmokers (55.3% females) aged 2.5–95 years.
Lung function data were collated, and prediction equations derived using the LMS (λ, µ, σ) method, which allows simultaneous modelling of the mean (mu), the coefficient of variation (sigma) and skewness (lambda) of a distribution family.
After discarding 23,572 records, mostly because they could not be combined with other ethnic or geographic groups, reference equations were derived for healthy individuals from 3–95 years for Caucasians (N=57,395), African Americans (N=3,545), and North (N=4,992) and South East Asians (N=8,255). FEV1 and FVC between ethnic groups differed proportionally from that in Caucasians, such that FEV1/FVC remained virtually independent of ethnic group. For individuals not represented by these four groups, or of mixed ethnic origins, a composite equation taken as the average of the above equations is provided to facilitate interpretation until a more appropriate solution is developed.
Spirometric prediction equations for the 3–95 age range are now available that include appropriate age-dependent lower limits of normal. They can be applied globally to different ethnic groups. Additional data from the Indian subcontinent, Arab, Polynesian, Latin American countries, and Africa will further improve these equations in the future.
To evaluate, among older persons, the association between respiratory impairment and hospitalization for chronic obstructive pulmonary disease (COPD), based on spirometric Z-scores (Lambda-Mu-Sigma [LMS]) and a competing risk approach.
Using data on 3,563 white participants aged 65–80 years (Cardiovascular Health Study), we evaluated the association of LMS-defined respiratory impairment with incident COPD hospitalization and the competing outcome of death without COPD hospitalization, over a 5-year period. Respiratory impairment included airflow limitation (mild, moderate, and severe) and restrictive-pattern.
Over a 5-year period, 276 (7.7%) participants had incident COPD hospitalization, whereas 296 (8.3%) died without COPD hospitalization. The risk of COPD hospitalization was elevated more than 2-fold in LMS-defined mild and moderate airflow limitation and restrictive-pattern (adjusted hazard ratio [HR]: 2.25 [1.25, 4.05], 2.54 [1.53, 4.22], and 2.65 [1.82, 3.86], respectively), and more than 8-fold in LMS-defined severe airflow limitation (adjusted HR: 8.33 [6.24, 11.12]). Conversely, only LMS-defined restrictive-pattern was associated with the competing outcome of death without COPD hospitalization (adjusted HR: 1.68 [1.22, 2.32]).
In white older persons, LMS-defined respiratory impairment is strongly associated with an increased risk of COPD hospitalization. These results support the LMS method as a basis for defining respiratory impairment in older persons.
Spirometry; Lambda-Mu-Sigma; COPD hospitalization
Recent epidemiological studies have suggested an increased risk of venous thromboembolism (VTE) in lung fibrosis. Large-scale epidemiological data regarding the risk of VTE in pulmonary fibrosis-associated mortality have not been published.
Using data from the National Center for Health Statistics from 1988–2007, we determined the risk of VTE in decedents with pulmonary fibrosis in the USA.
We analysed 46,450,489 records, of which 218,991 met our criteria for idiopathic pulmonary fibrosis. Among these, 3,815 (1.74%) records also contained a diagnostic code for VTE. The risk of VTE in pulmonary fibrosis decedents was 34% higher than in the background population, and 44% and 54% greater than among decedents with chronic obstructive pulmonary disease and lung cancer, respectively. Those with VTE and pulmonary fibrosis died at a younger age than those with pulmonary fibrosis alone (females: 74.3 versus 77.4 yrs (p<0.0001); males: 72.0 versus 74.4 yrs (p<0.0001)).
Decedents with pulmonary fibrosis had a significantly greater risk of VTE. Those with VTE and pulmonary fibrosis died at a younger age than those with pulmonary fibrosis alone. These data suggest a link between a pro-fibrotic and a pro-coagulant state.
Epidemiology; idiopathic pulmonary fibrosis; mortality; pulmonary fibrosis; venous thromboembolism
Alveolar elastic fibres are key targets of proteases during the pathogenesis of chronic obstructive pulmonary disease (COPD). In the current study, we hypothesised that a response to injury leads to enhanced alveolar elastin gene expression in very severe COPD.
Lung samples obtained from 43 patients, including 11 with very severe COPD (stage 4), 10 donors, 10 with moderate/severe COPD (stage 2–3) and 12 non-COPD subjects, were analysed for elastin mRNA expression by real-time RT-PCR and in situ hybridisation. Alveolar elastic fibres were visualised using Hart's staining of sections of frozen inflated lungs obtained from 11 COPD stage 4 patients and three donor lungs.
Compared with donors, non-COPD and stage 2–3 COPD, elastin mRNA expression was significantly increased in very severe COPD lungs (12-fold change), and localised in situ hybridisation induced elastin expression to alveolar walls. Compared with donors, alveolar elastic fibres also comprised a greater volume fraction of total lung tissue in very severe COPD lungs (p<0.01), but elastic fibre content was not increased per lung volume, and desmosine content was not increased.
The present study demonstrates enhanced alveolar elastin expression in very severe COPD. The efficiency of this potential repair mechanism and its regulation remain to be demonstrated.
Chronic obstructive pulmonary disease; elastin; emphysema; gene expression
Strategies to improve pulmonary endothelial barrier function are needed to reverse the devastating effects of vascular leak in acute respiratory distress syndrome (ARDS). FTY720 is a pharmaceutical analogue of the potent barrier-enhancing phospholipid, sphingosine 1-phosphate (S1P). FTY720 decreases vascular permeability through an incompletely characterized mechanism that differs from S1P. Here we describe its barrier-promoting effects on intracellular signaling and junctional assembly formation in human pulmonary endothelium.
Permeability of cultured human pulmonary endothelial cells was assessed by transendothelial electrical resistance (TER) and dextran transwell assays. Junctional complex formation was assessed by membrane fractionation and immunofluorescence. Pharmacologic inhibitors and siRNA were utilized to determine the effects of individual components on permeability.
Unlike S1P, FTY720 failed to induce membrane translocation of adherens junction or tight junction proteins. β-catenin, occludin, claudin-5, or ZO-1/ZO-2 siRNAs did not alter FTY720-induced barrier enhancement. FTY720 induced FAK phosphorylation and focal adhesion formation with FAK siRNA partially attenuating the prolonged phase of barrier enhancement. Inhibition of Src, PKA, PKG, PKC, or PP2A failed to alter FTY720-induced barrier enhancement. FTY720 increased c-Abl tyrosine kinase activity, and c-Abl siRNA attenuated peak barrier enhancement after FTY720.
FTY720 enhances endothelial barrier function by a novel pathway involving c-Abl signaling.
c-Abl tyrosine kinase; vascular endothelium; FTY720; junctional complexes; vascular permeability
Mutations in bone morphogenetic protein receptor type 2 (BMPR2) cause familial pulmonary arterial hypertension (FPAH), but the penetrance is reduced and females are significantly overrepresented. In addition, gene expression data implicating the oestrogen-metabolising enzyme CYP1B1 suggests a detrimental role of oestrogens or oestrogen metabolites. We examined genetic and metabolic markers of altered oestrogen metabolism in subjects with a BMPR2 mutation.
Genotypes for CYP1B1 Asn453Ser (N453S) were determined for 140 BMPR2 mutation carriers (86 females and 54 males). Nested from those subjects, a case–control study of urinary oestrogen metabolite levels (2-hydroxyoestrogen (2-OHE) and 16α-hydroxyoestrone (16α-OHE1)) was conducted in females (five affected mutation carriers versus six unaffected mutation carriers).
Among females, there was four-fold higher penetrance among subjects homozygous for the wild-type genotype (N/N) than those with N/S or S/S genotypes (p=0.005). Consistent with this finding, the 2-OHE/16α-OHE1 ratio was 2.3-fold lower in affected mutation carriers compared to unaffected mutation carriers (p=0.006).
Our findings suggest that variations in oestrogens and oestrogen metabolism modify FPAH risk. Further investigation of the role of oestrogens in this disease with profound sex bias may yield new insights and, perhaps, therapeutic interventions.
Bone morphogenetic protein receptor 2; CYP1B1; genetic polymorphism; oestrogen; pulmonary hypertension; sex
To investigate age-related changes in sleepiness symptoms associated
with sleep disordered breathing (SDB).
Wisconsin Sleep Cohort participants were assessed with
polysomnography, Epworth Sleepiness Scale (ESS) and Multiple Sleep Latency
Test (MSLT). SDB was defined as an apnea/hypopnea index≥15
events/hour, sleepiness as ESS≥10 and MSLT≤5 minutes. Odds
ratios were calculated using generalized estimating equations associating
sleepiness with SDB, and conditional logistic regression examining changes
in longitudinal sleepiness status (ESS only). Models were, a priori,
stratified by gender.
ESS was measured in 1281 participants and MSLT in 998, at multiple
time points (ESS n=3695; MSLT n=1846). Significant interactions were found
between SDB and age in men, but not women. The odds ratios (OR) modeled for
sleepiness in a 40 year old male with SDB were significant, compared to a
male without SDB (OR: ESS 2.1; MSLT 2.9); however, these associations were
not significant at 60 years. The within-subject odds ratio for sleepiness
was also significant at 40 years (OR: 3.4), but not at 60 years.
The age-related reductions in the association between sleepiness and
SDB may have clinical implications for the diagnosis and treatment of SDB in
older people since sleepiness is often used as a therapeutic marker.
Sleep disordered breathing; Obstructive sleep apnea; Aging; Sleepiness
An unexplained increase in the incidence of parapneumonic empyema (PPE) in pneumonia cases has been reported in recent years. The present study investigated the genetic and biological specifications of new isolates of torque teno mini virus (TTMV) detected in pleural effusion samples from children hospitalised for severe pneumonia with PPE.
A pathogen discovery protocol was applied in undiagnosed pleural effusion samples and led to the identification of three new isolates of TTMV (TTMV-LY). Isolated TTMV-LY genomes were transfected into A549 and human embryonic kidney 293T cells and viral replication was assessed by quantitative real-time PCR and full-length genome amplification. A549 cells were further infected with released TTMV-LY virions and the induced-innate immune response was measured by multiplex immunoassays.
Genetic analyses of the three TTMV-LY genomes revealed a classic genomic organisation but a weak identity (<64%) with known sequences. We demonstrated the in vitro replication of TTMV-LY in alveolar epithelial cells and the effective release of infectious viral particles. We also showed a selective production of inflammatory mediators in response to TTMV infection.
This study reports the description of replicative TTMV-LY isolated from parapneumonic effusions of children hospitalised with PPE, suggesting a potential role of the virus in the pathogenesis of pneumonia.
Vascular endothelial growth factor (VEGF) is an angiogenic factor implicated in asthma severity. The objective of the present study was to determine whether VEGF single nucleotide polymorphisms (SNPs) are associated with asthma, lung function and airway responsiveness.
The present authors analysed 10 SNPs in 458 white families in the Childhood Asthma Management Program (CAMP). Tests of association with asthma, lung function and airway responsiveness were performed using PBAT software (Golden Helix, Inc. Bozeman, MT, USA; available at www.goldenhelix.com). Family and population-based, revpeated measures analysis of airflow obstruction were conducted. Replication studies were performed in 412 asthmatic children and their parents from Costa Rica.
Associations with asthma, lung function and airway responsiveness were observed in both cohorts. SNP rs833058 was associated with asthma in both cohorts. This SNP was also associated with increased airway responsiveness in both populations. An association of rs4711750 and its haplotype with forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio in both cohorts was observed. Longitudinal analysis in CAMP confirmed an association of rs4711750 with FEV1/FVC decline over ~4.5 yrs of observation.
VEGF polymorphisms are associated with childhood asthma, lung function and airway responsiveness in two populations, suggesting that VEGF polymorphisms influence asthma susceptibility, airflow obstruction and airways responsiveness.
Airflow obstruction; asthma; single nucleotide polymorphisms; vascular endothelial growth factor
Polymeric immunoglobulin receptor (pIgR) expression is downregulated in lung cancer, but its implications in lung tumourigenesis remain unknown. We hypothesised that loss of pIgR expression occurs early, and is associated with cell proliferation and poor prognosis.
pIgR expression was evaluated by immunohistochemistry in airways of patients with normal mucosa, pre-invasive lesions and invasive lesions, and correlated with clinical outcomes. 16-HBE and A549 cells stably transfected with pIgR were tested for proliferation, apoptosis and cell cycle progression.
Immunostaining was strong in normal epithelium, but severely reduced in pre-invasive lesions and most lung cancers. Persistent expression was associated with younger age and adenocarcinoma subtype but not survival. pIgR overexpression significantly reduced A549 and 16-HBE proliferation. Growth inhibition was not due to cell cycle arrest, increased apoptosis or endoplasmic reticulum stress, but we observed altered expression of genes encoding for membrane proteins, including NOTCH3. Interestingly, NOTCH3 expression was inversely correlated with pIgR expression in cell lines and tissues.
pIgR expression was lost in most lung cancers and pre-invasive bronchial lesions, suggesting that pIgR downregulation is an early event in lung tumourigenesis. pIgR overexpression in A549 and 16-HBE cells inhibited proliferation. Future investigations are required to determine the mechanisms by which pIgR contributes to cell proliferation.
Differentiation; lung adenocarcinoma; lung pre-invasive lesions; polymeric immunoglobulin receptor; proliferation