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Differential impact of conventional and low-dose oral hormone therapy (HT), tibolone and raloxifene on functionality of the activated protein C system.
Thromb Haemost. 2007 Jun; 97(6):938-43.TH

Abstract

Recent studies have shown that hormone therapy (HT) is associated with an acquired resistance to activated protein C (APC). The aims of the present study were to evaluate a possible dose-response relationship and differential effects of different HT regimens on functionality of the APC system. Two hundred two healthy women were randomly assigned to receive treatment for 12 weeks with tablets containing either low-dose HT containing 1 mg 17ss-oestradiol + 0.5 mg norethisterone acetate (NETA) (n = 50), conventional-dose HT containing 2 mg 17ss-oestradiol and 1 mg NETA (n = 50), 2.5 mg tibolone (n = 51), or 60 mg raloxifene (n = 51). Normalized APC system sensitivity ratios (nAPCsr) were determined in plasma collected at baseline and after 12 weeks using a thrombin generation-based APC resistance test probed with either recombinant APC (rAPC) or thrombomodulin (rTM). NAPCsr increased in both the conventional- and low-dose HT groups, consistent with reduced sensitivity to APC. The increase was slightly more pronounced in the conventional-dose group, but the difference between the two HT groups was not statistically significant. The sensitivity to APC was only marginally altered in those allocated to tibolone. Consequently, tibolone showed a different phenotype as compared with the low-dose HT group. A small increase in nAPCsr with both rAPC and rTM was seen in the raloxifene-group, but the increase was less than in the low-dose HT group. Our findings indicate that oestrogen-progestin therapy induces an APC resistant phenotype, which may be related to dose, whereas tibolone and raloxifene only marginally alter the sensitivity to APC.

Authors+Show Affiliations

Department of Haematology Ullevål University Hospital Trust, Oslo, Norway. a.l.eilertsen@medisin.uio.noNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

17549295

Citation

Eilertsen, Anette L., et al. "Differential Impact of Conventional and Low-dose Oral Hormone Therapy (HT), Tibolone and Raloxifene On Functionality of the Activated Protein C System." Thrombosis and Haemostasis, vol. 97, no. 6, 2007, pp. 938-43.
Eilertsen AL, Liestøl S, Mowinckel MC, et al. Differential impact of conventional and low-dose oral hormone therapy (HT), tibolone and raloxifene on functionality of the activated protein C system. Thromb Haemost. 2007;97(6):938-43.
Eilertsen, A. L., Liestøl, S., Mowinckel, M. C., Hemker, H. C., & Sandset, P. M. (2007). Differential impact of conventional and low-dose oral hormone therapy (HT), tibolone and raloxifene on functionality of the activated protein C system. Thrombosis and Haemostasis, 97(6), 938-43.
Eilertsen AL, et al. Differential Impact of Conventional and Low-dose Oral Hormone Therapy (HT), Tibolone and Raloxifene On Functionality of the Activated Protein C System. Thromb Haemost. 2007;97(6):938-43. PubMed PMID: 17549295.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Differential impact of conventional and low-dose oral hormone therapy (HT), tibolone and raloxifene on functionality of the activated protein C system. AU - Eilertsen,Anette L, AU - Liestøl,Sigurd, AU - Mowinckel,Marie-Christine, AU - Hemker,H C, AU - Sandset,Per-Morten, PY - 2007/6/6/pubmed PY - 2007/8/19/medline PY - 2007/6/6/entrez SP - 938 EP - 43 JF - Thrombosis and haemostasis JO - Thromb. Haemost. VL - 97 IS - 6 N2 - Recent studies have shown that hormone therapy (HT) is associated with an acquired resistance to activated protein C (APC). The aims of the present study were to evaluate a possible dose-response relationship and differential effects of different HT regimens on functionality of the APC system. Two hundred two healthy women were randomly assigned to receive treatment for 12 weeks with tablets containing either low-dose HT containing 1 mg 17ss-oestradiol + 0.5 mg norethisterone acetate (NETA) (n = 50), conventional-dose HT containing 2 mg 17ss-oestradiol and 1 mg NETA (n = 50), 2.5 mg tibolone (n = 51), or 60 mg raloxifene (n = 51). Normalized APC system sensitivity ratios (nAPCsr) were determined in plasma collected at baseline and after 12 weeks using a thrombin generation-based APC resistance test probed with either recombinant APC (rAPC) or thrombomodulin (rTM). NAPCsr increased in both the conventional- and low-dose HT groups, consistent with reduced sensitivity to APC. The increase was slightly more pronounced in the conventional-dose group, but the difference between the two HT groups was not statistically significant. The sensitivity to APC was only marginally altered in those allocated to tibolone. Consequently, tibolone showed a different phenotype as compared with the low-dose HT group. A small increase in nAPCsr with both rAPC and rTM was seen in the raloxifene-group, but the increase was less than in the low-dose HT group. Our findings indicate that oestrogen-progestin therapy induces an APC resistant phenotype, which may be related to dose, whereas tibolone and raloxifene only marginally alter the sensitivity to APC. SN - 0340-6245 UR - https://www.unboundmedicine.com/medline/citation/17549295/Differential_impact_of_conventional_and_low_dose_oral_hormone_therapy__HT__tibolone_and_raloxifene_on_functionality_of_the_activated_protein_C_system_ DB - PRIME DP - Unbound Medicine ER -