Wheat flour exposure results in recruitment of inflammatory cells in the lungs of healthy individuals

Inflammation in induced sputum after aluminium oxide exposure: an experimental chamber study

INTRODUCTION

Workers in aluminium production are exposed to a complex mixture of particles and gases potentially harmful to the airways, among them aluminium oxide (Al2O3). With the use of an exposure chamber, we aimed to examine the effects of short-term controlled exposure to Al2O3 on lung function and inflammatory markers in healthy volunteers.

METHODS

15 men (age 19-31) were exposed in random order to clean air or Al2O3 particles (3.8-4.0 mg/m(3)) for 2 h including 30 min exercise (stationary bike, 75 W). The permissible exposure level (PEL) for Al2O3 by Occupational Safety and Health Administration, USA, is 5 mg/m(3) time weighted average (TWA). Sham and particle exposures were separated by at least 2 weeks. Spirometry was carried out, and induced sputum and blood samples were collected 48 h before and 4 and 24 h after exposure.

RESULTS

Levels of sputum neutrophils (mean (±SEM)) was increased 24 h post-Al2O3 vs pre-Al2O3 exposure (43% (4) vs 31% (4), p=0.01) and the protein level of interleukin (IL)-8 had a 4.8 (0.9)-fold change increase 24 h after exposure (p<0.01). Following Al2O3 exposure, gene signatures in sputum were significantly increased related to several pathways.

CONCLUSIONS

The present study suggests that controlled exposure to Al2O3 particles at levels below PEL (TWA) induces airway inflammation in healthy humans marked by elevated neutrophils and elevated IL-8. In addition, increased expression of genes associated with several biological processes was observed in sputum. Interestingly, inhaled Al2O3-induced effects were localised to the airways and not systemic.

Bakery flour dust exposure causes non-allergic inflammation and enhances allergic airway inflammation in mice

BACKGROUND

Baker's asthma is one of the most commonly reported occupational lung diseases in countries where fresh bread is baked daily in large quantities, and is characterized by rhinitis, bronchial hyperresponsiveness, and reversible airflow obstruction. Epidemiological studies have identified pre-existing atopy as an important risk factor for developing baker's asthma, yet the aetiology and pathogenesis of baker's asthma remain poorly understood.

OBJECTIVE

We sought to develop a mouse model of baker's asthma that could be used to characterize the development and progression of baker's asthma.

METHODS

We were unable to sensitize mice to bakery flour dust or flour dust extract. We assessed total inflammatory cells, cellular differential, total serum IgE and the pro-inflammatory cytokine response to oropharyngeally instilled bakery flour dust or flour dust extract by itself or in the context of ovalbumin (OVA) sensitization and challenge.

RESULTS

Both bakery flour dust and flour dust extract consistently elicited a neutrophilic inflammation in a Toll-like receptor 4-independent manner; suggesting that endotoxin is not playing a role in the inflammatory response to flour dust. Moreover, bakery flour dust and dust extract significantly enhance the inflammatory response in OVA-sensitized and challenged mice.

CONCLUSIONS

Bakery flour dust and flour dust extract are strongly pro-inflammatory and can cause non-allergic airway inflammation and can enhance allergen-mediated airway inflammation.

Large Organic Aerosols in a Dynamic and Continuous Whole-Body Exposure Chamber Tested on Humans and on a Heated Mannequin

Exposure to large airborne organic aerosols may cause respiratory and skin symptoms. The use of human exposure chambers permits safe mechanistic studies of the effect of inhalation or dermal deposition of such particles. The performance of a dynamic and continuous whole-body human exposure chamber using turbulent air mixing during exposure to these organic aerosols of humans and of a new heated mannequin was evaluated. Variability of temporal and spatial distribution of the airborne particle concentration, and aerodynamic aerosol size distribution of the inhalable fraction, were evaluated. The temporal and spatial distribution of these aerosols close to the breathing zone during an exposure session was typically < or = 10%, which is low for airborne particles of this size. In a larger section around a human, only slightly higher spatial variation was found. Variability between exposure sessions was also low (< 10%). Only limited effect of relative humidity for the organic aerosols was observed. The aerodynamic particle size distribution curves differed slightly, but some were comparable to those in occupational environments. The outcome of the performance tests as measured with the heated mannequin was almost the same as with humans, indicating that the mannequin could be used in preparatory tests in this type of chamber.