Elevated placental soluble vascular endothelial growth factor receptor-1 inhibits angiogenesis in preeclampsia.
Preeclampsia is an inflammatory disorder in which serum levels of vascular endothelial growth factor (VEGF) and its soluble receptor-1 (sVEGFR-1, also known as sFlt-1) are elevated. We hypothesize that VEGF and placenta growth factor (PlGF) are dysregulated in preeclampsia due to high levels of sVEGFR-1, which leads to impaired placental angiogenesis. Analysis of supernatants taken from preeclamptic placental villous explants showed a four-fold increase in sVEGFR-1 than normal pregnancies, suggesting that villous explants in vitro retain a hypoxia memory reflecting long-term fetal programming. The relative ratios of VEGF to sVEGFR-1 and PlGF to sVEGFR-1 released from explants decreased by 53% and 70%, respectively, in preeclampsia compared with normal pregnancies. Exposure of normal villous explants to hypoxia increased sVEGFR-1 release compared with tissue normoxia (P<0.001), as did stimulation with tumor necrosis factor-alpha (P<0.01). Conditioned medium (CM) from normal villous explants induced endothelial cell migration and in vitro tube formation, which were both attenuated by pre-incubation with exogenous sVEGFR-1 (P<0.001). In contrast, endothelial cells treated with preeclamptic CM showed substantially reduced angiogenesis compared with normal CM (P<0.001), which was not further decreased by the addition of exogenous sVEGFR-1, indicating a saturation of the soluble receptor. Removal of sVEGFR-1 by immunoprecipitation from preeclamptic CM significantly restored migration (P<0.001) and tube formation (P<0.001) to levels comparable to that induced by normal CM, demonstrating that elevated levels of sVEGFR-1 in preeclampsia are responsible for inhibiting angiogenesis. Our finding demonstrates the dysregulation of the VEGF/PlGF axis in preeclampsia and offers an entirely new therapeutic approach to its treatment.
Department of Reproductive and Vascular Biology, The Medical School, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TG, UK. a.s.ahmed@bham.ac.uk
Shakil
S
Ahmad
Asif
A
Ahmed
D017398:Alternative Splicing; D000818:Animals; D001011:Aorta / Q000166:cytology; D015687:Cell Hypoxia; D002478:Cells, Cultured / Q000187:drug effects; D002633:Chemotaxis / Q000187:drug effects; D002824:Chorionic Villi / Q000378:metabolism* / Q000473:pathology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology; D005260:Female; D006801:Humans; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010100:Oxygen / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D000072483:Placenta Growth Factor; D011225:Pre-Eclampsia / Q000097:blood* / Q000503:physiopathology; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000032:analysis; D011993:Recombinant Fusion Proteins / Q000494:pharmacology / Q000502:physiology; D012995:Solubility; D034421:Sus scrofa; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis / Q000494:pharmacology; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000097:blood / Q000235:genetics / Q000502:physiology*
D017077:Culture Media, Conditioned; C000608036:PGF protein, human; D010446:Peptide Fragments; D011257:Pregnancy Proteins; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000072483:Placenta Growth Factor; D040281:Vascular Endothelial Growth Factor Receptor-1; D010100:Oxygen