Estrogen receptors in mast cells from arterial walls

We examined the presence of estrogen receptors (ER) in vascular mast cells and a possible genomic effect of estrogens on the expression of mast cell (MC) mediators such as chymase, TNFα, NOS and IL-10, which are known to affect the course of atherosclerosis. Immunocytochemical detection of mast cell tryptase and the co-localization of ERs in MCs from abdominal aortic vessels from 10 fertile woman, 10 postmenopausal women and 15 men was performed. The genomic expression of IL-10, TNFα, and NOS was analyzed by RT-PCR and chymase activity by spectrophotometry after 24 h incubation with 17-β estradiol (0.2-0.5 ng/mL) in rat purified peritoneal MCs.
A similar number of MCs were found in both intima and adventitia layers from men, and fertile and postmenopausal women, while ERs were detected only in the arterial walls from fertile women. The mRNA expressions of IL-10 and TNFα, as well as chymase activity, were not affected. A moderate increment of NO and both NOS, and a reduction in TNFα cytotoxicity was observed after incubating peritoneal MCs with 17- β estradiol at a concentration of 0.5 ng/mL. Taken together, these results indicate that vascular MCs express ERs. The data demonstrate that estrogens can directly modify vascular MC activity. This is a novel mechanism of synergistic cooperation for the protective role of estrogens in the genesis of atherosclerosis.