Apoptosis in lung development and neonatal lung injury.

A healthy organism maintains an integrated balance between proliferating, differentiating, and dying cells. Some cells are irreplaceable, some cells complete their functions and are then sacrificed, and some cells live a finite lifetime, to be replaced by another generation. Apoptosis is the last phase of a cell's destiny and a distinct form of programmed cell death. It is characterized by loss of cell function and rapid morphological changes, culminating in cell death without inflammation. Apoptosis has been found to play an important role in the normal regulation of organogenesis and morphogenesis during development. Apoptosis is a fundamental feature in the development of many tissue systems, including the immune and nervous systems, as well as in the development of the kidneys and heart. The significance of apoptosis in lung development has been largely overlooked. Physical forces during development may play a role in directing apoptosis in remodeling the lung. This review summarizes current knowledge regarding apoptosis during lung development, with a particular emphasis on the potential role of mechanpotransduction as a stimulus for apoptosis.