According to a recent study at the Perelman School of Medicine at the University of Pennsylvania, there exists a new type of cell  which they call respiratory airway secretory cells (RASCs) that potentially plays a key role in human lung disease. The findings of the study, published in Nature, indicated that  RASCs have stem-cell-like properties enabling them to regenerate other cells that are essential for the normal functioning of alveoli and that cigarette smoking and COPD can disrupt the regenerative functions of RASCs. The researchers pointed out that correcting this disruption could be a good way to treat COPD.