Elevated platelet-derived growth factor-B in congenital cystic adenomatoidmalformations requiring fetal resection

Background: During lung development, platelet-derived growth factor-BB (PDG F-BB) is maximal during the canalicular stage and decreases by the saccular stage. PDGF-BB stimulates lung growth by increasing cell proliferation. Fe tal CCAMs have been shown to have an elevated proliferative index, but it i s not known why some CCAMs rapidly enlarge in utero and cause fetal hydrops . The authors hypothesized that the high proliferative index and rapid enla rgement of some fetal CCAMs may be caused by persistently elevated PDGF-BB production compared with normal fetal lung. Methods: To test this hypothesis, tissue was obtained at the time of resect ion from two fetal CCAMs (22 weeks), three full-term CCAMs, and three norma l fetal lungs (21 to 22 weeks). PDGF-BB production by fetal CCAMs was compa red with normal age-matched fetal lung using immunohistochemistry, reverse transcriptionase-polymerase chain reaction (RT-PCR), and Western blot analy sis. Results: CCAMs resulting in fetal hydrops and requiring fetal resection had strong mesenchymal immunostaining for PDGF-BB next to epithelial lined cys ts, increased PDGF-B gene expression by RT-PCR, and elevated PDGF-BB protei n by Western blot, compared with normal age-matched fetal lung. Term CCAMs had minimal PDGF-BB staining, PDGF-B gene expression, and PDGF-BB protein p roduction. Conclusions: CCAMs that grew rapidly and progressed to hydrops, requiring i n utero resection, demonstrated increased mesenchymal PDGF-E gene expressio n and PDGF-BB protein production compared with age-matched normal fetal lun g, which may, in part, be responsible for the autonomous growth and prolife ration seen in hydropic feta I CCAMs. Copyright (C) 1999 by W.B. Sanders Co mpany.