Elastosis and fragmentation of fibers of the elastic system in fatal asthma

Fibers of the elastic system (FES) are important in regulating airway paten cy and lung elastic recoil. Their possible role in modulating bronchoconstr iction is not fully understood. Chronic inflammation and mechanical stretch ing present in asthma could lead to conformational alterations in the FES, participating in the mechanism of airway remodeling observed in this diseas e. In airway mucosa, two layers of FES are discernible: one superficial net work, attached to the basement membrane, and a deeper network, lying close to the airway smooth muscle. Using image analysis and conventional morphome try, we analyzed airway content of FES in central and peripheral airways in 31 cases of fatal asthma and in 10 control lungs. Slides were stained usin g the oxidized resorcin-fuchsin method. Optical analysis revealed fragmenta tion of the FES in the superficial network of central asthmatic airways. Mo rphometry showed the presence of elastosis in central asthmatic airways whe n the entire thickness of the mucosa was considered. In the superficial net work elastic fiber content was significantly decreased. These results indic ate that FES participate in airway remodeling in asthma. We also suggest th at disrupture of fiber attachments at the basement membrane in the superfic ial layer could impair the mechanism of airway recoil in asthmatic patients .