Historical milestones in the development of tibolone (Livial®)

Short-term administration of tibolone reduces inflammation and oxidative stress in the hippocampus of ovariectomized rats fed high-fat and high-fructose

Inflammation and oxidative stress are critical events involved in neurodegeneration. In animal models, it has been shown that chronic consumption of a hypercaloric diet, which leads to inflammatory processes, affects the hippocampus, a brain region fundamental for learning and memory processes. In addition, advanced age and menopause are risk factors for neurodegeneration. Hormone replacement therapy (HRT) ameliorates menopause symptoms. Tibolone (TB), a synthetic hormone, exerts estrogenic, progestogenic and androgenic effects on different tissues. We aimed to determine the effect of short-term TB administration on oxidative stress and inflammation markers in the hippocampus of ovariectomized rats fed a high-fat-and-fructose diet (HFFD). Adult female rats were ovariectomized (OVX) and fed standard diet or HFFD-consisting of 10% lard supplemented chow and 20% high-fructose syrup in the drinking water-and administered vehicle or TB (1 mg/kg for seven days). Finally, we administered hormone receptor antagonists (MPP, RU486 or FLU) to each of the OVX + HFFD + TB groups. Bodyweight, triglycerides and cholesterol, oxidative stress and inflammation markers, and the activity and expression of antioxidant enzymes were quantified in the hippocampus of each experimental group. We observed that short-term TB administration significantly reduced body weight, AGEs, MDA levels, increased SOD and GPx activity, improved GSH/GSSG ratio, and reduced IL-6 and TNF-α. Our findings suggest that short-term administration of TB decreases oxidative stress and reduces inflammation caused by HFFD and early estrogenic decline. These effects occurred via estrogen receptor alpha.

A Review of Analytical Methods for the Determination of Tibolone: Pharmacokinetics and Pharmaceutical Formulations Analysis and Application in Doping Control

Background:

Tibolone is a synthetic steroid commercialized by Organon under the brand name Livial (Org OD14), which is used in hormone therapy for menopause management and treatment of postmenopausal osteoporosis. Tibolone is defined as a selective tissue estrogenic activity regulator (STEAR) demonstrating tissue-specific effects on several organs such as brain, breast, urogenital tract, endometrium, bone and cardiovascular system.

Aims:

This work aims to (1) present an overview of important published literature on existing methods for the analysis of tibolone and/or its metabolites in pharmaceutical formulations and biological fluids and (2) to conduct a critical comparison of the analytical methods used in doping control, pharmacokinetics and pharmaceutical formulations analysis of tibolone and its metabolites.

Results and conclusions:

The major analytical method described for the analysis of tibolone in pharmaceutical formulations is High Pressure Liquid Chromatography (HPLC) coupled with ultraviolet (UV) detection, while Liquid Chromatography (LC) or Gas Chromatography (GC) used in combination with Mass Spectrometry (MS) or tandem mass spectrometry (MS/MS) is employed for the analysis of tibolone and/or its metabolites in biological fluids.

Extensive early mineralization of pre-osteoblasts, inhibition of osteoclastogenesis and faster peri-implant bone healing in osteoporotic rat model: principle effectiveness of bone-specific delivery of Tibolone as evaluated in vitro and in vivo

Hydrophobic drug molecules pose a significant challenge in immobilization on super-hydrophobic metallic surfaces like conventional titanium implants. Pre-coating surface modifications may yield a better platform with improved wettability for such purposes. Such modifications, as depicted in this study, were hypothesized to provide the requisite roughness to assist deposition of polymers like silk fibroin (SF) as a drug-binding matrix in addition to significant improvement in early protein adsorption, which facilitates faster cellular adhesion and proliferation. A silk-based localized drug delivery module was developed on the titanium surface and tested for its surface roughness, wettability, biocompatibility and in vitro differentiation potential of cells cultured on the coated metallic surfaces with/without external supplementation of the active metabolite of Tibolone. Conditioning of the matrix-coated implants with osteogenic as well as osteoclastogenic media supplemented with Tibolone stimulated the expression of early osteogenic gene and calcium deposition in the extracellular matrix. Significant inhibition in resorptive activity was also observed in the presence of the drug. To assess the efficacy of localized delivery of Tibolone via topographically modified titanium implants for inducing early peri-implant bone formation, osteoporosis was artificially induced in rats subjected to bilateral ovariectomy and implants were placed thereafter. Bone-specific release of Tibolone through the biomimetic matrix in osteoporotic rats collectively indicated significant improvement in peri-implant bone growth after 2 and 4 weeks (p < 0.05 compared to dummy-coated implants). These findings demonstrate for the first time that Tibolone released from SF matrix-coated implants can accelerate the biological stability of bone fixtures.

Tibolone as Hormonal Therapy and Neuroprotective Agent

Tibolone (TIB), a selective tissue estrogenic activity regulator (STEAR) in clinical use by postmenopausal women, activates hormonal receptors in a tissue-specific manner. Estrogenic activity is present mostly in the brain, vagina, and bone, while the inactive forms predominate in the endometrium and breast. Conflicting literature on TIB's actions has been observed. While it has benefits for vasomotor symptoms, bone demineralization, and sexual health, a higher relative risk of hormone-sensitive cancer has been reported. In the brain, TIB can improve mood and cognition, neuroinflammation, and reactive gliosis. This review aims to discuss the systemic effects of TIB on peri- and post-menopausal women and its role in the brain. We suggest that TIB is a hormonal therapy with promising neuroprotective properties.

Tibolone attenuates inflammatory response by palmitic acid and preserves mitochondrial membrane potential in astrocytic cells through estrogen receptor beta

Palmitic acid (PA) induces several metabolic and molecular changes in astrocytes, and, it is involved in pathological conditions related to neurodegenerative diseases. Previously, we demonstrated that tibolone, a synthetic steroid with estrogenic, progestogenic and androgenic actions, protects cells from mitochondrial damage and morphological changes induced by PA. Here, we have evaluated which estrogen receptor is involved in protective actions of tibolone and analyzed whether tibolone reverses gene expression changes induced by PA. Tibolone actions on astrocytic cells were mimicked by agonists of estrogen receptor α (ERα) and β (ERβ), but the blockade of both ERs suggested a predominance of ERβ on mitochondria membrane potential. Expression analysis showed a significant effect of tibolone on genes associated with inflammation such as IL6, IL1B and miR155-3p. It is noteworthy that tibolone attenuated the increased expression of TERT, TERC and DNMT3B genes induced by palmitic acid. Our results suggest that tibolone has anti-inflammatory effects and can modulate pathways associated with DNA methylation and telomeric complex. However, future studies are needed to elucidate the role of epigenetic mechanisms and telomere-associated proteins on tibolone actions.

Antioxidant effect of the active metabolites of tibolone

Certain steroidal compounds have an antioxidant effect in humans. Our aim was to test whether the synthetic steroid tibolone and its metabolites are also able to display such a property. For this, granulocytes from healthy men and women were incubated for two hours with different concentrations (10(-7), 10(-8), 10(-9 )M) of either estradiol, tibolone, 3α-hydroxytibolone, 3β-hydroxytibolone, Δ(4)-tibolone, 3α-sulfated-tibolone, 3α-17β-disulfated-tibolone, 3β-sulfated-tibolone or 3β-17β-disulfated-tibolone. Superoxide anion generation of neutrophils was measured by photometry. Results of different steroids were given as percentages of their controls. A more simple superoxide generating system, the xanthine-xanthine oxidase reaction was also tested. We found that granulocyte superoxide production did not differ from the control using 10(-9 )M of steroids. Using 10(-8 )M concentration: estradiol (80.9 ± 2.5%); 3β-sulfated-tibolone (83.3 ± 4.7%); 3β-17β-disulfated-tibolone (81.0 ± 4.2%) caused a significant decrease in superoxide production, compared to the control. In addition at 10(-7 )M, 3β-hydroxytibolone and 3α-sulfated-tibolone also showed antioxidant effects. In the xanthine-xanthine oxidase system estradiol (67.4 ± 1.0%), 3α-sulfated-tibolone (85.8 ± 5.3%), 3α-17β-disulfated-tibolone (71.9 ± 2.5%), 3β-sulfated-tibolone (73.9 ± 5.0%), and 3β-17β-disulfated-tibolone (65.8 ± 3.4%) caused a significant decrease in superoxide production. Conclusively, although tibolone itself did not show significant antioxidant capacity, most of its active metabolites have antioxidant effects.