Salmeterol Does Not Alter Increased Bronchial Responsiveness Caused by Organic Dust Exposure

Organic dust-induced lung injury and repair: Bi-directional regulation by TNFα and IL-10

Exposure to organic dust increases chronic airway inflammatory disorders. Effective treatment strategies are lacking. It has been reported that hog barn dust extracts (HDE) induce TNFα through protein kinase C (PKC) activation and that lung inflammation is enhanced in scavenger receptor A (SRA/CD204) knockout (KO) mice following HDE. Because interleukin (IL)-10 production can limit excessive inflammation, it was hypothesized here that HDE-induced IL-10 would require CD204 to effect inflammatory responses. C57BL/6 wild-type (WT), SRA KO, and IL-10 KO mice were intranasally challenged daily for 8 days with HDE and subsequently rested for 3 days with/without recombinant IL-10 (rIL-10) treatment. Primary peritoneal macrophages (PM) and murine alveolar macrophages (MH-S cells) were treated in vitro with HDE, SRA ligand (fucoidan), rIL-10, and/or PKC isoform inhibitors. HDE induced in vivo lung IL-10 in WT, but not SRA KO mice, and similar trends were demonstrated in isolated PM from same treated mice. Lung lymphocyte aggregates and neutrophils were elevated in in vivo HDE-treated SRA and IL-10 KO mice after a 3-d recovery, and treatment during recovery with rIL-10 abrogated these responses. In vitro rIL-10 treatment reduced HDE-stimulated TNFα release in MH-S and WT PM. In SRA KO macrophages, there was reduced IL-10 and PKC zeta (ζ) activity and increased TNFα following in vitro HDE stimulation. Similarly, blocking SRA (24 hr fucoidan pre-treatment) resulted in enhanced HDE-stimulated macrophage TNFα and decreased IL-10 and PKCζ activation. PKCζ inhibitors blocked HDE-stimulated IL-10, but not TNFα. Collectively, HDE stimulates IL-10 by an SRA- and PKCζ-dependent mechanism to regulate TNFα. Enhancing resolution of dust-mediated lung inflammation through targeting IL-10 and/or SRA may represent new approaches to therapeutic interventions.

Respiratory health effects of large animal farming environments

With increases in large animal-feeding operations to meet consumer demand, adverse upper and lower respiratory health effects in exposed agriculture workers are a concern. The aim of this study was to review large animal confinement feeding operational exposures associated with respiratory disease with a focus on recent advances in the knowledge of causative factors and cellular and immunological mechanisms. A PubMed search was conducted with the keywords airway, farm, swine, dairy, horse, cattle inflammation, organic dust, endotoxin, and peptidoglycan, among items were published between 1980 and now. Articles were selected based on their relevance to environmental exposure and reference to airway diseases. Airway diseases included rhinitis, sinusitis, mucus membrane inflammation syndrome, asthma, chronic bronchitis, chronic obstructive pulmonary disease, hypersensitivity pneumonitis, and organic dust toxic syndrome. There is lower prevalence of immunoglobulin (Ig) E-mediated asthma and atopy in farmers and their children, but organic dust worsens existing asthma. Multiple etiologic factors are linked to disease, including allergens, organic dusts, endotoxins, peptidoglycans, and gases. Large animal confinement feeding operations contain a wide diversity of microbes with increasing focus on gram-positive bacteria and archaebacteria as opposed to gram-negative bacteria in mediating disease. Toll-like receptors (TLR) and nucleotide oligomerization domain (NOD)-like innate immune pathways respond to these exposures. Finally, a chronic inflammatory adaptation, tolerance-like response in chronically exposed workers occurs. Large animal confinement farming exposures produce a wide spectrum of upper and lower respiratory tract diseases due to the complex diversity of organic dust, particulates, microbial cell wall components, and gases and resultant activation of various innate immune receptor signaling pathways.

[Quality prescribing of long-acting beta-agonists. Results of an intervention in Primary Care]

OBJECTIVE

To assess an intervention aimed to reduce inappropriate prescribing of long-acting beta-agonists (LABA) in Primary Care. MATERIAL AND METHODS;

DESIGN

Quasi-experimental pre/post study without control group.

SETTING

Aljarafe Primary Health Care Area (Seville, Spain).

PARTICIPANTS

General practitioners with LABA prescriptions without inhaled corticosteroids (iCT), who worked more than 40% of working days in the study period. Study unit: Simple randomised sample of patients with LABA prescriptions without iCT.

INTERVENTIONS

Mailing educational material with recommendations on the appropriate use of LABA and a list of their patients with inappropriate prescriptions.

MAIN MEASUREMENT

Appropriateness of LABA prescriptions as indicated in the Product Summary Characteristics. Patient age, sex, type of LABA and diagnoses were analysed.

SOURCES

An information system for billing computerized prescriptions and medical history.

RESULTS

Before intervention, prescriptions were inappropriate in 70.3% of patients, and 51.8% received LABA without iCT for unapproved conditions. A diagnosis associated with a respiratory condition was not recorded in the Computerised Medical Records of 18.5% of the patients. After intervention, the percentage of inappropriate prescriptions in the sample dropped to 4.5%, mainly due to a review of the treatment (LABA cessation or iCT addition).

CONCLUSIONS

There is a high level of inappropriate use of LABA in Primary Health Care. Mailing educational materials combined with the list of patients with an inappropriate LABA prescription to general practitioners seems to be an effective strategy to improve quality prescribing in respiratory pathologies.

Respiratory issues in beef and pork production: recommendations from an expert panel

This paper summarizes "Respiratory Issues in Confined Feeding Operations," a panel discussion at the Agricultural Safety and Health Council of America/National Institute for Occupational Safety and Health conference, "Be Safe, Be Profitable: Protecting Workers in Agriculture," Dallas/Fort Worth, Texas, January 27-28, 2010. Occupational exposure to confined animal feeding operations is associated with cough, wheezing, and shortness of breath. Published data shows that 20% to 40% of hog confinement workers experience such symptoms, although most are able to continue working in this industry. Endotoxin is one component of hog barn dust that is associated with respiratory disease in workers. Endotoxin levels on cattle feedlots can also be in the range linked with occupational lung disease. The cattle industry has not yet prepared guidance documents for producers, in part because much less is known about the prevalence of lung disease in its workers. However, the pork industry provides information for pork producers on reducing their respiratory health risks through a multifaceted approach, including the use of respirators. Some jobs cannot be done safely without respiratory protection, such as entering manure pits. It is less clear for other jobs when respirators should be worn. Use of respiratory protection should be considered but not mandated for all persons working in close proximity to livestock in dusty conditions. A respiratory protection program may also serve as a cost effective biosecurity measure to protect animals from human pathogens such as influenza virus. Proper design and management of barn ventilation systems is critical for maintaining temperature and humidity levels for optimal animal growth; as well as decreasing the level of gases and respirable dusts. The pork and the cattle industries support occupational health and safety; however, the governmental guidance and recommendations for such programs are limited for the agricultural industries as a whole. The industries should lead the way in the effort to improve respiratory protection for workers. Overall, a team approach that includes input from managers, workers, and veterinarians is important for the reduction of respiratory hazards on livestock farms.

Fluticasone and ibuprofen do not add to the effect of salmeterol on organic dust-induced airway inflammation and bronchial hyper-responsiveness

BACKGROUND

Exposure in a pig house causes airway inflammation and bronchial hyper-responsiveness which are not influenced by anti-asthma drugs, including a beta(2)-agonist (salmeterol).

OBJECTIVES

We hypothesized that a glucocorticoid or a cyclo-oxygenase-inhibitor synergistically interacts with salmeterol offering a protection against dust-induced increased bronchial responsiveness and airway inflammation. As data did not confirm previous results a retrospective analysis of pooled data on dust-induced bronchial hyper-responsiveness from four other studies was performed.

DESIGN

Fluticasone or ibuprofen was administered for 1 week and salmeterol or placebo was inhaled 1 h prior to a 3-h exposure in a pig barn in a double-blind, placebo-controlled, cross-over design (2-3 weeks apart) in 12 healthy subjects. Lung function, bronchial responsiveness to methacholine and inflammatory markers were evaluated before and after exposure. Pre- and postexposure bronchial responsiveness in nontreated subjects was retrospectively evaluated from four previous studies.

SUBJECTS

Twelve healthy, nonatopic nonsmokers.

RESULTS

Salmeterol partially protected against bronchial hyper-responsiveness but did not influence inflammatory markers. Fluticasone and ibuprofen did not add to these effects. The retrospective analysis showed that PD(20)FEV(1) after exposure in a pig barn is almost totally independent of pre-exposure PD(20)FEV(1)-level; all subjects end up at the same low postexposure PD(20)FEV(1).

CONCLUSION

Contradictory to our previous results, salmeterol offered partial protection against enhanced bronchial responsiveness induced by exposure in a pig barn. This effect was not modified by fluticasone or ibuprofen. Our data clearly demonstrate that interventions altering bronchial responsiveness must be compared between groups with similar prechallenge bronchial responsiveness or in a cross-over design.