Regulation of endothelial cell function by phytoestrogens

SANDOVAL M.; CUTINI P.; RAUSCHEMBERGER M.B.; MASSHEIMER V.

Congreso; XXVI Reunión Anual de la Asociación Argentina de Osteología y Metabolismo Mineral; 2009

Epidemiological studies propose that phytoestrogens rich diet may attenuate bone loss in post-menopausal women. In this study, we evaluated whether the isoflavone genistein (Gen) would modulate the cellular and molecular events associated with vascular disease. We employed rat endothelial cell (EC) cultures. AfteR 24 hours of treatment, Gen increased DNA synthesis in synchronized EC (70.52±6.77 vs 41.24±4.49 cpm103/mg prot, Gen vs Control). This action was prevented by the presence of estrogen receptor antagonist ICI 182780 or l-NAME (nitric oxide synthase inhibitor), suggesting that the stimulation of EC growth involves ER and nitric oxide production. To study Gen´s effect on leukocyte adhesion to EC, isolated monocytes were added to EC previously exposed to Gen or to bacterial lipopolysaccharide (LPS). Maximal adhesion was detected in LPS group, meanwhile Gen prevented monocyte adhesion (267±36, 417±21.5, 160±9.8 cells/μl for control, LPS, and Gen, p menor a 0.01). Since leukocyte adhesion depends on cellular adhesion molecules (CAMs) expression, we evaluated Gen regulation of CAM expression using RT-PCR. VCAM-1, P-selectine, and E selectine mRNA levels were diminished in cells exposed to Gen, compared to control or LPS group, suggesting that the inhibition of monocyte adhesion would be due to Gen´s effect on CAM?RNA expression. To investigate the action of the Gen on EC apoptosis (DNA laddering) we used H2O2 as an apoptosis inducer. In the presence of H2O2, EC DNA was completely fragmented, but if EC were incubated with Gen 24 hours prior to H2O2 addition, DNA laddering was partially inhibited. In summary, the results obtained shows that Gen stimulates EC proliferation and reduced monocyte adhesion and EC apoptosis induced by cytotoxic agents, suggesting a potential benefit action of the phytoestrogen at the vascular level.