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.
Preventive and Occupational Medicine Department, Foundation Maggiore Policlinic Hospital Mangiagalli and Regina Elena, Milan, Italy.
P
P
Marraccini
D M
DM
Brass
J W
JW
Hollingsworth
S
S
Maruoka
S
S
Garantziotis
D A
DA
Schwartz
D000818:Animals; D001249:Asthma / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology; D018893:Bronchoalveolar Lavage; D016207:Cytokines / Q000276:immunology; D004195:Disease Models, Animal; D004391:Dust / Q000276:immunology; D005433:Flour / Q000009:adverse effects*; D007073:Immunoglobulin E / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000276:immunology; D009784:Occupational Diseases / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology; D010047:Ovalbumin / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000502:physiology
D016207:Cytokines; D004391:Dust; D008070:Lipopolysaccharides; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D007073:Immunoglobulin E; D010047:Ovalbumin