KDR and endothelial dysfunction: Studies have confirmed that Hsp90 functions as a proangiogenic agent, especially during embryogenesis, and binds to VEGFR-1 and displaces VEGF, prompting VEGFR-2 activation and intermolecular transphosphorylation and causing endothelial dysfunction after amplified angiogenesis, which is a common manifestation of PE [23].