Abstract
Background: The extracellular domains of some membrane proteins can be cleaved and shed from the cell. In chronic asthma model, the shedded ectodomains of α1β1 and α2β1 integrins are accumulated in airway wall, but it is unknown if soluble integrins are expressed during asthma. Aims: We evaluated the levels of α1β1 and α2β1 integrins in serum and bronchoalveolar lavage fluid (BALF) in an experimental model of chronic asthma. Methods: Sensitized guinea pigs were intermittently challenged with ovalbumin (OVA; applied every 10 days). At twelfth OVA challenge, the airway hyperresponsiveness (AHR) to histamine and the levels of cytosolic and extracellular domains of α1β1 and α2β1 integrins in serum and BALF were evaluated (n=6). Controls received saline solution instead of OVA (n=6). Results: From the first challenge on, OVA induced acute transient bronchoobstruction followed by development of AHR. The levels of extracellular and cytosolic domains of α1β1 integrin in BALF and serum in asthma model guinea pigs were similar between groups. The expression of cytosolic domain of α1β1 integrin in BALF and serum was similar in both groups; nevertheless, the extracellular domain of α2β1 integrin increase in serum and BALF of asthma model guinea pigs in comparison to controls. Conclusions: We suggest that the soluble ectodomain of α2β1 integrin, an integrin involved in matrix organization andcell adhesion, might be a putative molecular marker of chronic asthma.
- © 2014 ERS