Dataset Information

Secondhand smoke exposure causes bronchial hyperreactivity via transcriptionally upregulated endothelin and 5-hydroxytryptamine 2A receptors.

ABSTRACT:

Background

Cigarette smoke exposure is strongly associated with airway hyperreactivity (AHR) which is the main characteristic seen in asthma. The intracellular MAPK signaling pathways are suggested to be associated with the airway damage to the AHR. In the present study, we hypothesize that secondhand cigarette smoke (SHS) exposure upregulates the bronchial contractile receptors via activation of the Raf/ERK/MAPK pathway.

Methodology/principal findings

Rats were exposed to SHS for 3 h daily for up to 8 weeks. The receptor agonists-induced bronchial contractile reactivity was analyzed with a sensitive myograph system. The mRNA transcription and protein translation of the target receptors and the kinases in Raf/ERK/MAPK pathway were investigated by real-time PCR, Western blotting and immunofluorescence, respectively. Compared with exposure to fresh air, SHS induced enhanced bronchial contractile responses mediated by the 5-hydroxytryptamine 2A (5-HT(2A)) receptors as well as the endothelin type B (ET(B)) and type A (ET(A)) receptors. The response curves were shifted toward the left with an increased maximal contraction (E(max)) demonstrating that SHS induced AHR. Additionally, the mRNA and protein levels of the 5-HT(2A), ET(B) and ET(A) receptors were increased. Furthermore, SHS exposure increased the phosphorylation of Raf-1 and ERK1/2, but it did not alter p38 or JNK. A Raf-1 inhibitor (GW5074) suppressed the SHS-induced increase in the expression of 5-HT(2A) and ET(A) receptors and the receptor-mediated AHR.

Conclusions/significance

Our findings show that SHS exposure induces transcriptional upregulation of the 5-HT(2A), ET(B) and ET(A) receptors in rat bronchial smooth muscle cells, which mediates AHR. The Raf/ERK/MAPK pathway is involved in SHS-associated receptor upregulation and AHR.

SUBMITTER: Cao L

PROVIDER: S-EPMC3428315 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Publications

Secondhand smoke exposure causes bronchial hyperreactivity via transcriptionally upregulated endothelin and 5-hydroxytryptamine 2A receptors.

Cao Lei L Zhang Yaping Y Cao Yong-Xiao YX Edvinsson Lars L Xu Cang-Bao CB

PloS one 20120827 8

<h4>Background</h4>Cigarette smoke exposure is strongly associated with airway hyperreactivity (AHR) which is the main characteristic seen in asthma. The intracellular MAPK signaling pathways are suggested to be associated with the airway damage to the AHR. In the present study, we hypothesize that secondhand cigarette smoke (SHS) exposure upregulates the bronchial contractile receptors via activation of the Raf/ERK/MAPK pathway.<h4>Methodology/principal findings</h4>Rats were exposed to SHS for ...[more]

PMID: 22952915

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Project description:Background and objectivesActive smoking is associated with higher risk of various diseases. However, the risk of CKD development in nonsmokers exposed to secondhand smoke is not well elucidated. We aimed to investigate the association between secondhand smoke exposure and the risk of CKD development among never-smokers.Design, setting, participants, & measurementsA total of 131,196 never-smokers with normal kidney function, who participated in the Korean Genome and Epidemiology Study from 2001 to 2014, were analyzed. The participants were classified into three groups on the basis of frequency of secondhand smoke exposure, assessed with survey questionnaires; no exposure, <3 days per week, and ≥3 days per week. The association between secondhand smoke and CKD, defined as eGFR<60 ml/min per 1.73 m2, was examined in the cross-sectional analysis. In addition, the risk of incident CKD development was analyzed in a longitudinal cohort of 1948 participants without CKD at baseline, which was a subset of the main cohort.ResultsThe mean age of participants was 53 years, and 75% were women. Prevalent CKD was observed in 231 (1.8%), 64 (1.7%), and 2280 (2.0%) participants in the ≥3 days per week, <3 days per week, and no exposure groups. The odds ratio (OR) of prevalent CKD was significantly higher in the groups exposed to secondhand smoke than the no exposure group (<3 days per week: OR, 1.72; 95% confidence interval [95% CI], 1.30 to 2.27; and ≥3 days per week: OR, 1.44; 95% CI, 1.22 to 1.70). During a mean follow-up of 104 months, CKD occurred in 319 (16%) participants. Multivariable Cox analysis revealed that the risk for CKD development was higher in participants exposed to secondhand smoke than the no exposure group (<3 days per week: hazard ratio, 1.59; 95% CI, 0.96 to 2.65; and ≥3 days per week: hazard ratio, 1.66; 95% CI, 1.03 to 2.67).ConclusionsExposure to secondhand smoke was associated with a higher prevalence of CKD as well as development of incident CKD.

Project description:IntroductionDespite knowledge about major health effects of secondhand tobacco smoke (SHS) exposure, systematic incorporation of SHS screening and counseling in clinical settings has not occurred.MethodsA three-round modified Delphi Panel of tobacco control experts was convened to build consensus on the screening questions that should be asked and identify opportunities and barriers to SHS exposure screening and counseling. The panel considered four questions: (1) what questions should be asked about SHS exposure; (2) what are the top priorities to advance the goal of ensuring that these questions are asked; (3) what are the barriers to achieving these goals; and (4) how might these barriers be overcome. Each panel member submitted answers to the questions. Responses were summarized and successive rounds were reviewed by panel members for consolidation and prioritization.ResultsPanelists agreed that both adults and children should be screened during clinical encounters by asking if they are exposed or have ever been exposed to smoke from any tobacco products in their usual environment. The panel found that consistent clinician training, quality measurement or other accountability, and policy and electronic health records interventions were needed to successfully implement consistent screening.ConclusionsThe panel successfully generated screening questions and identified priorities to improve SHS exposure screening. Policy interventions and stakeholder engagement are needed to overcome barriers to implementing effective SHS screening.ImplicationsIn a modified Delphi panel, tobacco control and clinical prevention experts agreed that all adults and children should be screened during clinical encounters by asking if they are exposed or have ever been exposed to smoke from tobacco products. Consistent training, accountability, and policy and electronic health records interventions are needed to implement consistent screening. Increasing SHS screening will have a significant impact on public health and costs.

Project description:BackgroundAirports may represent significant sources of secondhand smoke (SHS) exposure for both travelers and employees. While previously common smoking rooms have largely disappeared from US airports, smoking continues to occur outdoors at terminal entrances. SHS may be especially high at arrival areas, since they oftentimes are partially enclosed by overhead departures, creating stagnant microenvironments. This study assessed particulate matter <2.5 microns in diameter (PM2.5), a common surrogate for SHS, at airport terminal locations to evaluate both outdoor exposure risk and possible indoor drift of SHS from outdoor sources.MethodsA convenience sample of nine airport terminal arrival areas in the US state of Florida was surveyed between February and July 2018. PM2.5 levels were assessed outdoors and indoors at terminal entrances and at control areas far into terminal interiors. We also examined the impact of smoking location on SHS exposure by correlating cigarette and passing vehicle counts with PM2.5 levels at terminals with contrasting proximity of designated smoking locations to terminal entrances.ResultsAlthough outdoor PM2.5 levels (mean 17.9, SD 6.1 µg/m3) were significantly higher than indoors (p < 0.001), there was no difference between indoor areas directly inside terminal entrances and areas much further interior (mean 8.8, SD 2.6 vs mean 8.5, SD 3.0 µg/m3, p=0.49). However, when smoking areas were in close proximity to terminal entrances, the number of lit cigarettes and vehicular traffic per minute predicted 70% of the variance of PM2.5 levels (p < 0.001), which was attributable mostly to the cigarette number (β = 0.83; 95% CI (0.55 to 1.11); p < 0.001). This effect was not observed at smoking areas further away.ConclusionPM2.5 data did not suggest indoor drift from outside smoking. Nevertheless, absolute exposure outdoors was high and correlated with the location of designated smoking areas. Further studies are needed to examine the effect of microclimate formation on exposure risk.

Dataset Information

Secondhand smoke exposure causes bronchial hyperreactivity via transcriptionally upregulated endothelin and 5-hydroxytryptamine 2A receptors.

Background

Methodology/principal findings

Conclusions/significance

Publications

Secondhand smoke exposure causes bronchial hyperreactivity via transcriptionally upregulated endothelin and 5-hydroxytryptamine 2A receptors.

Similar Datasets

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