ABSTRACT
Clinical observations and basic studies show that progesterone and progestins have a variable influence on endothelial function. Dydrogesterone (DG) is a widely used progestin, but its endothelial actions have not been thoroughly assessed. In this study, we investigated the effects of DG and its metabolite 20-α-dihydro-dydrogesterone (DHD), natural progesterone as well as medroxyprogesterone acetate, on the expression of leukocyte adhesion molecules in human endothelial cells using an in vitro experimental endothelial inflammation system. Our findings show that all progestins significantly suppress endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and inter-cellular adhesion molecule-1 (ICAM-1) induced by bacterial lypopolysaccharide (LPS). These inhibitory effects of DG and DHD require activation of progesterone receptor. DG and DHD decrease adhesion molecule expression associated with LPS administration by preventing nuclear translocation of the pro-inflammatory transcription factor nuclear factor-κB. In addition, DG and DHD do not alter the anti-inflammatory effects of 17ß-estradiol. In conclusion, DG and DHD decrease endothelial inflammatory responses induced by LPS, via reduced expression of the pro-atherogenic adhesion molecules VCAM-1 and ICAM-1. These actions may be relevant for the vascular effects of DG.
