Endoglin (CD105) immuno-expression in human foetal and neonatal lungs.
Endoglin is a 180 KDa glycoprotein mainly expressed on endothelial cells of newly formed vessels. Its expression is increased by the hypoxia inducible factor 1 (HIF-1), a potent stimulator of VEGF expression. The relative hypoxic environment in which foetal lung develops favours HIF-1 dependent gene expression, including the endoglin and VEGF ones. Herein, we analysed endoglin immunoexpression in the human neonatal and foetal lung throughout gestation. Lungs from 18 foetuses (9-41 weeks), 7 preterm and 2 term infants were submitted to the immunohistochemical study. A slight immunostaining was found in some mesenchymal aggregates in the lungs of foetuses at the first trimester of pregnancy. At mid gestation, endoglin was evidenced in peri-tubular mesenchymal stem cells or in peri-canalicular vessels and in the endothelia of peri-bronchial vessels; by contrast, no immunoreaction was observed in case of Down syndrome or in a foetus with cardiac malformations. At late gestation and in preterm infants, endoglin antibody labelled endothelia of the alveolar capillaries and of peri-bronchial vessels. In case of alveolar capillary dysplasia (ACD) or macrosomy associated with maternal diabetes, endoglin expression was restricted to peri-bronchial vessels; no immunoreaction was encountered in foetuses with IUGR (intra-uterine growth restriction) or massive pulmonary haemorrhage. Lungs of term infants both displayed atelectasis; there was no evidence of endoglin immunoexpression in one case, whereby only the endothelia of peri-bronchial vessels were stained in the other. Our study suggests that lung vasculogenesis endures throughout gestation. Absence of endoglin staining in some pathologic conditions may reflect lung vasculogenesis disorders; nonetheless, since each pathologic state is represented by a single case in our cohort, further studies are required to clarify this issue.
Barresi
Valeria
V
Department of Human Pathology, University of Messina, Italy. valeriabarresi@hotmail.com
Grosso
Maddalena
M
Vitarelli
Enrica
E
Granese
Roberta
R
Barresi
Gaetano
G
D015703:Antigens, CD / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D000071063:Endoglin; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D047109:Fetal Development; D005333:Fetus; D019085:Fluorescent Antibody Technique, Direct; D005865:Gestational Age; D006801:Humans; D007124:Immunoenzyme Techniques; D007231:Infant, Newborn; D008168:Lung / Q000098:blood supply / Q000196:embryology*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D001261:Pulmonary Atelectasis / Q000378:metabolism / Q000473:pathology; D011956:Receptors, Cell Surface / Q000378:metabolism*
D015703:Antigens, CD; D015415:Biomarkers; C064206:ENG protein, human; D000071063:Endoglin; D011956:Receptors, Cell Surface