Idiopathic Diffuse Hyperplasia of Pulmonary Neuroendocrine Cells and Airways Disease

IN contrast to fetal lungs, in which neuroendocrine cells are abundant and are thought to play a part in the paracrine regulation of lung development, normal adult lungs contain few neuroendocrine cells. 1 2 3 4 5 6 However, neuroendocrine-cell hyperplasia is frequently observed in subjects living at high altitude 7 and in association with various lung diseases, particularly among cigarette smokers. 8 9 10 11 12 13 Although the role of neuroendocrine cells in these conditions remains unclear, it is speculated that hyperplasia of pulmonary neuroendocrine cells is an adaptive response to hypoxia 7 or a secondary process associated with chronic lung disease. 7 8 9 10 11 12 Recent investigations suggest, however, that alterations in neuroendocrine-cell physiology may . . .