Progesterone Receptor Expression in Human Saphenous Veins

Abstract
Background Clinical and epidemiological observations regarding varicose veins, such as their predominance in women and the occurrence of venous stasis during sex-hormone therapy, the luteal phase of the menstrual cycle, and pregnancy, suggest a sex hormone–dependency of this venous pathology. In the present study, analysis of steroid receptors was used to determine if these effects were due to a direct hormonal action on the saphenous vein. Methods and Results Biopsy samples were obtained from patients undergoing stripping removal of varicose saphenous veins. Patients were men (n=5) and premenopausal (n=15) or postmenopausal (n=10) women. Progesterone receptors (PR) and estrogen receptors (ER) were determined by both enzyme immunoassay (EIA) and immunocytochemistry by use of monoclonal antibodies. Ninety percent of the biopsy samples showed PR positivity by EIA (range, 5 to 53 fmol/mg cytosol protein). When present, PR staining was observed in the cell nuclei of the tunica media and the subendothelial layer (neointima). No significant variation was observed in the PR content of different regions within the same saphenous vein. In contrast, no ER or extremely low levels of ER (Conclusions These results indicate that human saphenous veins from both sexes express PR, as previously described for arterial blood vessels. This observation suggests that progesterone acts directly on these veins via a classic receptor-mediated pathway.