EFFECTS OF SHORT-TERM GLUCOCORTICOIDS ON VON WILLEBRAND FACTOR IN MICE. PRELIMINARY RESULTS

ZAPATA VA; KEMPFER AC; PAIVA-PALOMINO J; ASTUDILLO OG; COSTA H; LAZZARI MA; SÁNCHEZ-LUCEROS A

Boston-USA

Congreso; XXII Congress of the International Society on Thrombosis and Haemostasis; 2009

International Society on Thrombosis and Haemostasis

Introduction Glucocorticoids are important in pregnancy and in the stress response. Many in vivo studies have examined the effects of glucocorticoids on hemostatic factors. We hypothesized that ACTH and corticosterone (CTC) could influence the VWF in mouse model. Objective: To determine if there is any influence of ACTH / CTC on VWF plasma levels and/or VWF promoter in mice. Methods: Animals: 8 week old BALB/c female mice from our mouse colony (20- 25 g in weight) were used. The procedures involving animals and their care were conducted in accordance to the Institutional Guide for the Care and Use of Laboratory Animals. Treatments: a- ACTH 2.8 g/d ip; b- CTC 2mg/k ip; c- a + mifepristone (RU, inhibitor of ACTH/CTC) 2mg/k ip; d- b + RU 2mg/k ip; e- LPS 30ug ip; f- vehicle. Eight hours later plasma and tissue samples (lung, aorta) were collected. Assays: VWF:Ag (ELISA). Tissue: VWF mRNA (qPCR). Results: VWF:Ag (IU/dL): a- 96±7,1; b- CTC 103±12.8; c- 105±7,0; d- 97±12.4; e- 184±16.9; f- 96±16,6. VWF:mRNA (cycle threshold, CT): a- 20,11±0,6; b- 19,54±1.53; c- 20,38±0.25; d- 18,58±1.7; e- 19,02±0,6; f- 19.2±0,6. VWF plasma levels did not change with ACTH and CTC treatments in BALB/c model. The LPS increased significantly the plasmatic VWF. On the contrary, VWF mRNA expression measured by qPCR did not show any changes. Conclusion: Although in vitro and in vivo evidences suggest that glucocorticoids may modulate VWF, the results show that there were no changes in our mice model. An important LPS-induced VWF release is probably due to an inflammatory reaction without affecting the molecular level.