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Updated: Jul 13, 2026
A Novel In vitro Model for Studying the Interactions Between Human Whole Blood and Endothelium
Published on: November 21, 2014
In vitro effects of tibolone and its metabolites on human vascular coronary cells
H Seeger1, H J Kloosterboer, M Studen
1Department of Endocrinology and Menopause, University's Women Hospital, Calwerstrasse 7, 72 076 Tuebingen, Germany.
Objectives:
Tibolone is a tissue selective compound with estrogenic, androgenic and progestogenic properties in classical bioassays. It is used for alleviation of menopausal symptoms and for osteoporosis prophylaxis in postmenopausal women. Only few data are available regarding the effects of tibolone on the cardiovascular system. We investigated therefore the in vitro effects of tibolone and its metabolites on the vasculature under special controlled conditions, using human female coronary endothelial and smooth muscle cells.
Methods:
The effect on the production of the following markers in endothelial cells from human female coronary arteries was evaluated: nitric oxide synthase, prostacyclin, endothelin, plasminogen-activator-inhibitor-1 (PAI-1), E-Selectin, Intercellular adhesion molecule (ICAM-1), monocyte attracting protein-1 (MCP-1) and the precursor of matrix metalloproteinase-1 (pro-MMP-1). Tibolone, its metabolites, estradiol (E2), E2/norethisterone (NET) and E2/medroxyprogesterone acetate (MPA) were tested at 0.1 microM and 1 microM. The markers were determined by enzyme immunoassays in the cell supernatant. Cell proliferation of smooth muscle cells from female coronary artery was measured by an adenosine triphosphate-assay.
Results:
Tibolone, its 3-hydroxy metabolites, E2/NET, E2/MPA and estradiol alone had significant effects on the synthesis of all markers tested. The magnitude of the tibolone effects, however, was mostly smaller than that of E2/NET and E2/MPA. Concerning smooth muscle cells tibolone and its 3-hydroxy metabolites also elicited an inhibition of the proliferation compared to control values. The strongest effect here was found for E2/NET and E2 alone, whereas E2/MPA had no effect.
Conclusion:
The results of this in vitro study conducted with cells of the most important vascular bed with respect to the problem of cardiovascular risk suggest that tibolone can positively influence the vasculature. However, these tibolone effects may depend on intact vascular cells and may vary due to the different atherosclerotic stages of the vessels. Thus, experimental studies are useful to explore mechanisms, but clearly cannot replace clinical studies.
Insights
Tibolone and its metabolites show positive in vitro effects on human coronary artery cells, influencing vascular markers and smooth muscle cell proliferation. Further clinical studies are needed to confirm these cardiovascular benefits.
Area of Science:
- Cardiovascular Pharmacology
- Endocrinology
- Cell Biology
Background:
- Tibolone is a selective tissue compound used for menopausal symptoms and osteoporosis.
- Limited data exist on tibolone's cardiovascular effects.
- This study investigates tibolone's in vitro impact on the vasculature.
Purpose of the Study:
- To evaluate the in vitro effects of tibolone and its metabolites on human female coronary artery endothelial and smooth muscle cells.
- To assess the influence on key vascular markers and cell proliferation.
Main Methods:
- Human female coronary artery endothelial and smooth muscle cells were used.
- Effects on nitric oxide synthase, prostacyclin, endothelin, PAI-1, E-Selectin, ICAM-1, MCP-1, and pro-MMP-1 were measured.
- Cell proliferation was assessed using an adenosine triphosphate assay.
Main Results:
- Tibolone, its 3-hydroxy metabolites, estradiol/NET, estradiol/MPA, and estradiol significantly affected vascular marker synthesis.
- Tibolone's effects were generally less potent than combined hormone therapies.
- Tibolone and its metabolites inhibited smooth muscle cell proliferation.
Conclusions:
- Tibolone may positively influence the vasculature in vitro.
- Effects are dependent on intact vascular cells and may vary with atherosclerotic stage.
- In vitro findings warrant further investigation in clinical studies.
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