Therapeutic approaches to promote lung repair. (a) Direct repair of the plasma membrane could be achieved using amphipathic compounds that seal injured membranes. (b) Exogenous stem cells to repair the denuded areas. (c) Administration of growth factors to stimulate the proliferation of endogenous stem cells. (d) Stimulation or (e) selective blockade of different matrix metalloproteinases (MMPs) to promote collagen processing or avoid the adverse effects of these enzymes.