PSEUDOMONAS-AERUGINOSA ADHERENCE TO REMODELING RESPIRATORY EPITHELIUM

Pseudomonas aeruginosa is an opportunistic organism, which frequently colonizes the respiratory tract of patients with impaired host defence , In cystic fibrosis (CF) patients, this pathogen causes a progressive destructive bronchitis and bronchiolitis and is responsible for high mortality. Normal respiratory epithelium is protected against bacteria via mucus and mucociliary clearance, Alteration of mucociliary cleara nce and of glycosylation of mucins in CF facilitates the access of bac teria to the underlying airway epithelial cells, Intact respiratory ep ithelium does not bind P. aeruginosa, whereas injured respiratory epit helium is highly susceptible to P. aeruginosa adherence, We found that the high affinity of respiratory epithelium, from CF and non-CF sourc es, for P. aeruginosa, during the wound repair process is related to t he apical expression of asialo ganglioside M1 (aG(M1)). The affinity o f repairing respiratory epithelium for P. aeruginosa is time-dependent , and is related to transient apical expression of aG(M1) at the surfa ce of repairing respiratory epithelial cells. CF respiratory epithelia l cells apically express more aG(M1) residues with relation to an incr eased affinity for P. aeruginosa than non-CF cells. High epithelial da mage followed by repair represents a major cause of P. aeruginosa adhe rence to airway epithelium in cystic fibrosis. However, P. aerurignosa adherence and colonization are not restricted to cystic fibrosis dise ase and P. aeruginosa pneumonia may also occur in severely immunocompr omised patients, suggesting that epithelial injury and decreased host- response favour the colonization of the airways by P. aeruginosa.