Stem cell therapy for lung diseases: From fundamental aspects to clinical applications

The respiratory system is a complex group of organs in the human body, all of which are necessary in breathing. Due to its special anatomy and composition, after exposure to various damaging factors such as micro particles, carbon granules and toxic gases, the respiratory system can be affected by a variety of damage without return to its original state. Currently, the prevalence of lung diseases, including asthma, and chronic obstructive pulmonary diseases, such as emphysema, has increased remarkably. New therapeutic approaches are desperately needed to discover regenerative medicine approaches, especially cell therapy. This review summarizes the recent advances in stem cell treatments and the research efforts conducted through the application of stem cell therapy for respiratory system diseases. In particular, researchers have used animal models to gather data about treating lung injury by stem cell transplantation. This review concentrated on the findings about route, timing and adjustment of cell transplantation dose, optimum stem cell type selection and potency marker of cells as therapeutic agents. These factors are essential subjects for approval and clinical transplantation. The current clinical trials aiming at treatment of lung diseases by stem cells are mentioned and discussed.