Endothelium-dependent dilatory effects of 3α-OH-tibolone in gracilis muscle arterioles of the female Wistar rat

Effects of menopause and tibolone on different cardiovascular biomarkers in healthy women

BACKGROUND AND AIM

The effects of tibolone on cardiovascular risk is not yet fully understood today. We designed this study to assess the effect of the menopausal status and tibolone treatment (2.5 mg/day for 3 months) on different biomarkers of cardiovascular risk in healthy women.

METHODS

Blood arterial pressure were measured, and blood samples collected for glucose, lipid profile (total cholesterol, high density lipoproteins, HDL, low density lipoproteins, and triglycerides), inflammatory (C-reactive protein, Interleukin-6, IL-6, tumor necrosis factor alpha, TNF alpha) and oxidative stress (hydroperoxides and antioxidant capacity) evaluation in 15 premenopausal (mean age: 30 +/- 4 years) and 15 postmenopausal (mean age: 52 +/- 3, mean time from menopause 1.4 +/- 0.4 years) women before and after tibolone treatment.

RESULTS

The menopausal status is associated with increased systolic and diastolic pressure (p<0.05), higher IL-6 (p<0.05) and TNF alpha (p<0.01), and lower antioxidants (p<0.01). However, blood pressure (p<0.05), glucose (p<0.05), TNF alpha (p<0.05) and HDL (p<0.05) fell after tibolone, which did not significantly affect levels of the other biochemical parameters.

CONCLUSIONS

As menopause is associated with increased blood pressure, inflammation and oxidative stress, tibolone restores blood pressure and has beneficial effect on inflammation and glycemia without worsening oxidative stress, although it also reduces HDL levels. Such modifications should be taken into account when tailoring menopausal therapies to specific requirements of each woman.

Rho kinase regulates renal blood flow by modulating eNOS activity in ischemia-reperfusion of the rat kidney

Renal ischemia-reperfusion (I/R) results in vascular dysfunction characterized by a reduced endothelium-dependent vasodilatation and subsequently impaired blood flow. In this study, we investigated the role of Rho kinase in endothelial nitric oxide synthase (eNOS)-mediated regulation of renal blood flow and vasomotor tone in renal I/R. Male Wistar rats were subjected to 60-min bilateral clamping of the renal arteries or sham procedure. One hour before the clamping, the Rho kinase inhibitor Y27632 (1 mg/kg) was intravenously infused. After I/R, renal blood flow was measured using fluorescent microspheres. I/R resulted in a 62% decrease in renal blood flow. In contrast, the blood flow decrease in the group treated with the Rho kinase inhibitor (YI/R) was prevented. Endothelium-dependent vasodilatation of renal arcuate arteries to ACh was measured ex vivo in a pressure myograph. These experiments demonstrated that the in vivo treatment with the Rho kinase inhibitor prevented the decrease in the nitric oxide (NO)-mediated vasodilator response. In addition, after I/R renal interlobar arteries showed a decrease in phosphorylated eNOS and vasodilator-stimulated phosphoprotein, a marker for bioactive NO, which was attenuated by in vivo Rho kinase inhibition. These findings indicate that in vivo inhibition of Rho kinase in renal I/R preserves renal blood flow by improving eNOS function.