Long-term effects of tibolone on circulating levels of vascular cell adhesion molecules and E-selectin in postmenopausal women

Antisclerothic effect of tibolone by reducing proinflammatory cytokines expression, ROS production and LDL-ox uptake in THP-1 macrophages

BACKGROUND

Cardiovascular disease is more frequent in menopausal women, which has been related to factor such as weight gain, altered fat distribution, and increased inflammation markers including adipokines (MCP-1, TNF-α, IL-6) and cytokines (IL-1, IL-6, TNF-α) produced by macrophages. In addition to their phagocytic activity, macrophages secrete cytokines and chemokines that induces cell recruitment, which is a process related to vascular damage that favors the formation of atheromatous plaques. Tibolone (Tb) therapy is used to reduce the symptoms of menopause as well as osteoporosis and it has been shown to decreases the risk of fractures.

METHODS

To investigate the effect of tibolone in macrophage enzymatic activity, gene expression of cytokines, and its effect on foam cells formation. We use phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 cells. The cells were incubated 24 h and 48 h using pre and post-treatment schemes. We evaluated total ROS determination by NBT assay, expression of cytokines (IL-1β, IL-6, TNF-α, NOS2, ARG1, TGFβ) by RT-qPCR and foam cell formation in THP-1 differentiated macrophages stimulated with PMA.

RESULTS

It was observed that the minor levels of total ROS determination were obtained with tibolone at 48 h in post-treatment scheme. Also, in a long term we found decrease the proinflammatory cytokines (IL-1β, IL-6 and TNF-α). Finally, with treatment for 24 h with P4 y Tb we observed fewer LDL vesicles into macrophages cytoplasm.

CONCLUSIONS

These results suggest that tibolone reduces the inflammatory process, also inhibits the foam cells formation; suggesting a possible role in reducing cardiovascular risk.

Short-term tibolone does not interfere with endothelial function: a double-blinded, randomized, controlled trial

Objective To evaluate the effect of short-term hormone replacement therapy with tibolone 2.5 mg daily on endothelial function of healthy postmenopausal women, using flow-mediated dilation (FMD) of the brachial artery. Methods We performed a randomized, double-blinded, placebo-controlled study. A total of 100 healthy postmenopausal women were randomly allocated to receive tibolone (n = 50) or placebo (n = 50) for 28 days. Measurement of the FMD of the brachial artery was performed before and after the use of tibolone and placebo. Results A total of 31 women completed the study in the tibolone group, and 32 women completed the study in the control group. The results of the FMD measurements obtained from the women in the two groups before treatment were similar (0.018 and 0.091, for tibolone and placebo, p = 0.57). The values of the FMD in women who used tibolone and placebo, before and after the treatment, were similar in both groups. The numbers of women who presented an increase in the values of the FMD in both groups were also similar. Conclusion Our results demonstrate that the administration of 2.5 mg tibolone to healthy postmenopausal women for 28 days does not promote endothelial-dependent vasodilation, measured by FMD of the brachial artery.

Drospirenone and levonorgestrel in combination with either 30 or 20 mcg ethinylestradiol reduce soluble adhesion molecules in Brazilian women; cross-sectional study

BACKGROUND

The objective of this study was to evaluate the effect of three contraceptive pills containing ethinylestradiol (EE) (20 or 30 mcg) in combination with drospirenone (DRSP) and levonorgestrel (LNG) on plasma concentration of adhesion molecules vascular cell adhesion molecule -1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and E-selectin.

STUDY DESIGN

A cross-sectional study was conducted with 72 participants (18-30 years old) distributed into three groups that used oral contraceptives containing EE 20 or 30 mcg combined with DRSP 3 mg or EE 30 mcg/LNG 150 mcg for at least 6 months. The control group was comprised of nonusers of contraceptives. Soluble VCAM-1, soluble ICAM-1 and soluble E-selectin were evaluated by enzyme-linked immunosorbent assay.

RESULTS

Compared to the control group, a significant decrease was found in VCAM-1 and ICAM-1 concentrations with use of DRSP/20 EE and LNG/30 EE.

CONCLUSIONS

DRSP/20 EE and LNG/30 EE induce favorable changes in endothelial function.

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.

Tibolone in postmenopausal women: a review based on recent randomised controlled clinical trials

AIM

To critically discuss the use of tibolone (T), in light of a series of very recent double-blind placebo (PL) controlled trials (LISA, LIFT, OPAL, THEBES, LIBERATE) conducted worldwide in a large number of postmenopausal women (PMW).

METHODS

The most relevant publications on T therapy in PMW were considered with emphasis on menopausal symptoms, quality of life, sexuality, bone, cardiovascular system (CVS) and oncologic risk.

RESULTS

T significantly relieves climacteric symptoms and improves mood and sexual well-being (LISA). T is as effective as estrogen-progestin therapy in preventing bone loss and reducing the relative risk of vertebral and non-vertebral fractures (LIFT). By using surrogate endpoints of the individual risks for the CVS, studies show mixed results, but a favourable effect on acute miocardial infarction and thromboembolism has been documented (THEBES, LIFT, OPAL). Although findings about endometrial and colon cancer are reassuring, conclusive data on breast cancer risk with T are not available and an increased risk of recurrence in women with previous breast cancer emerged (LIBERATE).

CONCLUSIONS

T is effective in treating menopausal syndrome with a good tolerability profile. In spite of some unsolved issues in term of safety, T is still a good treatment option for early PMW.

Effects of hormone treatment on hemostasis variables

A survey was made of the changes in hemostasis and related inflammatory biomarkers for hormone treatments (HT) of women. Treatments included were oral and non-oral estrogens combined or not with progestogens, raloxifene, tamoxifene, tibolone and ethinylestradiol in oral contraceptives with non-androgenic progestogens. Special attention was given to dosages lower than the present standard dose and we explored how treatment variants approached a situation of minimal changes in biomarkers. For oral unopposed estrogens, dose reduction effectively reduced the changes in some hemostasis markers, but not in a specific set of anticoagulant variables (antithrombin, protein S, tissue factor pathway inhibitor, and the endogenous thrombin potential assay for resistance to activated protein C). Inflammation markers from the liver showed a dose-dependent reduction but effects were not nullified at the lowest dose tested. It was concluded that adequate reduction of estrogen dose for these effects will coincide with the dose-range of efficacy. Androgenic progestogens may be suitable for further reducing the impact of estrogens on some of the anticoagulant variables; reductions of estrogen-induced C-reactive protein increases appear possible with specific progestogens (medroxyprogesterone actate, nomegestrol acetate). For non-oral unopposed estrogens, all variables except inflammation biomarkers from the vascular wall showed minimal changes. Reduction in vascular inflammatory biomarkers, considered to mark anti-inflammatory effects, is augmented by medroxyprogesterone actate or norethisterone acetate. It was concluded that unopposed, non-oral estrogen treatment is the present best available option approaching minimal effects of treatment on biomarkers. Progestogen selection requires more data. We postulated that minimal effects on all cardiovascular biomarkers should define the HT with maximal safety for venous and arterial vascular events. The survey has identified specific biomarkers sensitive to low-dose unopposed and opposed estrogen which can be used to characterize future preparations for HT.

Cardiovascular Effects of Tibolone: A Selective Tissue Estrogenic Activity Regulator

Traditionally, it was accepted that long-term hormone replacement therapy (HRT) has a cardiovascular beneficial effect in postmenopausal women with and without coronary artery disease (CAD). However, randomized trials in postmenopausal women have not shown any benefit in either primary or secondary prevention of cardiovascular events. Therefore, these findings have raised the question of whether traditional HRT (i.e., estrogen and progesterone) has a cardioprotective effect in women at risk for or with established CAD. Concerns about the use of conventional HRT have led to a search for alternatives. Tibolone is a synthetic compound with estrogenic, androgenic, and progestogenic properties that relieves climacteric symptoms and prevents postmenopausal bone loss. Tibolone possesses a tissue-selective mechanism of action that differs from that of estrogen and/or progestogen. Unlike these compounds, tibolone's metabolites play a central role in its mode of action. Tibolone is widely used for HRT. However, its clinical impact on cardiovascular disease is still under study. The current review focuses on the effects of tibolone on the cardiovascular system and discusses clinical investigations with this compound in postmenopausal women.