Enhanced expression of vascular endothelial growth factor in lungs of newborn infants with congenital diaphragmatic hernia and pulmonary hypertension.
BACKGROUND
Pulmonary hypoplasia accompanied by pulmonary hypertension resistant to treatment is an important feature of congenital diaphragmatic hernia (CDH). The pathogenesis of the pulmonary vascular abnormalities in CDH remains to be elucidated at the molecular level. Vascular endothelial growth factor (VEGF), an endothelial cell specific mitogen, is known to play a role in pulmonary angiogenesis and vascular remodelling but there are no data on VEGF expression in patients with CDH.


METHODS
Necroscopic lung specimens from 21 patients with CDH with lung hypoplasia and from seven age matched control newborn infants without lung hypoplasia were processed for immunohistochemical analysis using affinity purified anti-human VEGF antibodies. All the cases of CDH had pulmonary hypoplasia, indicated by a lung/body weight index of </=0.012, and pulmonary hypertension indicated by repeated cardiac ultrasonography. Cellular localisation of VEGF was semiquantitatively analysed using a staining score ranging from 0 (no staining) to 4 (very strong staining).


RESULTS
Significantly raised levels of VEGF immunoreactivity were observed in lung specimens from cases of CDH compared with controls. VEGF was detected mainly in the bronchial epithelium and the medial smooth muscle cells of large (>200 microm) and small (<200 microm) pulmonary arteries, the most intense staining being in the medial smooth muscle cells of the small pulmonary arteries. Endothelial cells were positive for VEGF staining in patients with CDH but not in controls.


CONCLUSIONS
This is the first study of VEGF expression in newborn infants with CDH. Increased levels of VEGF, especially in the small, pressure regulating pulmonary arteries, point to a potential role in vascular remodelling. This may reflect an unsuccessful attempt by the developing fetus to increase the pulmonary vascular bed in the hypoplastic lungs to alleviate the associated pulmonary hypertension.
Shehata
S M
SM
Department of Pediatric Surgery, Erasmus University, 3015 GJ Rotterdam, The Netherlands.
Mooi
W J
WJ
Okazaki
T
T
El-Banna
I
I
Sharma
H S
HS
Tibboel
D
D
D016022:Case-Control Studies; D016228:Endothelial Growth Factors / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism; D006548:Hernia, Diaphragmatic / Q000150:complications / Q000378:metabolism; D065630:Hernias, Diaphragmatic, Congenital; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications / Q000151:congenital* / Q000378:metabolism; D007150:Immunohistochemistry; D007231:Infant, Newborn; D008168:Lung / Q000002:abnormalities; D008222:Lymphokines / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000378:metabolism; D011651:Pulmonary Artery / Q000378:metabolism*; D018709:Statistics, Nonparametric; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors