Pulmonary endocrine cells in hypertensive pulmonary vascular disease.

A study was made of the number of pulmonary endocrine cells, immunoreactive for gastrin-releasing peptide (bombesin) or calcitonin, in the terminal bronchioles of 39 cases of pulmonary vascular disease. In 25 of these, the form of vascular disease was plexogenic pulmonary arteriopathy, primary in 12 and secondary in 13, while the remaining 14 subjects had a wide range of other varieties of hypertensive pulmonary vascular disease. We found that pulmonary endocrine cells, especially those containing bombesin, were increased in number in both the primary and secondary forms of plexogenic pulmonary arteriopathy but not in other varieties of pulmonary hypertension. The prominent bombesin-containing cells were found in cases with cellular plexiform lesions but occurred even more prominently at an earlier stage when vascular smooth muscle cells were migrating from the inner media into the intima.