Airways are exposed to a number of inhaled toxins,
pathogens, allergens, reactive gases, aerosols and irritant
particles. After a lung insult, some of the epithelial cells
are injured or damaged. These cells either detach or die
thus disruption of cell-cell and cell-matrix interaction and
also exposing the basement membrane. The normal
response to the injury is a mass transportation of factors
including Extra Cellular Matrix (ECM), various growth
factors and inflammatory cells. The epithelial cells in the
margin of the damage flatten and move to eventually
cover the wound. If this repair does not occur this
insult can result in a disease (Fig. 1).peer-reviewe
