Article

Resolution of allergic airways inflammation but persistence of airway smooth muscle proliferation after repeated allergen exposures.

Thoracic Medicine, National Heart and Lung Institute, Imperial College, London, UK.
Clinical & Experimental Allergy (impact factor: 5.03). 03/2004; 34(2):213-20.
Source: PubMed

ABSTRACT Chronic inflammation in asthmatic airways can lead to characteristic airway smooth muscle (ASM) thickening and pathological changes within the airway wall.
We investigated the long-term effects of repeated allergen exposure.
Brown-Norway (BN) rats sensitized to ovalbumin (OVA) were exposed to OVA or saline aerosol every third day on six occasions and studied 24 h, 7 days and 35 days after the final exposure. We measured airway inflammation, ASM cell proliferation (by incorporation of bromodeoxyuridine; BrdU) and bronchial responsiveness to acetylcholine.
At 24 h, in OVA-exposed rats, we detected elevated OVA-specific serum IgE, increased numbers of macrophages, eosinophils, lymphocytes and neutrophils in the bronchoalveolar lavage (BAL) fluid and increased numbers of MBP+ (major basic protein) eosinophils and CD2+ T cells within the bronchial submucosa. This coincided with increased numbers of ASM cells expressing BrdU and with bronchial hyper-responsiveness (BHR). At 7 days, BHR was detected in OVA-exposed rats, coincident with increased numbers of macrophages and lymphocytes in BAL fluid together with increased numbers of CD2+ T cells within the bronchial submucosa. This coincided with increased numbers of ASM cells expressing BrdU. By day 35, the number of ASM cells expressing BrdU remained elevated in the absence of cellular infiltration and BHR.
Repeated OVA-challenge results in persistent ASM cell proliferation in the absence of bronchial inflammation and BHR, which lasts for at least 1 week following cessation of exposure.

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Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

1 week
 
7 days
 
airway inflammation
 
ASM cell proliferation
 
asthmatic airways
 
bronchial hyper-responsiveness
 
bronchial inflammation
 
bronchial responsiveness
 
bronchial submucosa
 
bronchoalveolar lavage
 
CD2+ T cells
 
cellular infiltration
 
characteristic airway smooth muscle
 
Chronic inflammation
 
major basic protein
 
OVA-exposed rats
 
OVA-specific serum IgE
 
Repeated OVA-challenge results
 
saline aerosol
 
third day
 

S-Y Leung