J Cardiothorac SurgJ Cardiothorac SurgJournal of Cardiothoracic Surgery1749-8090BioMed Central46937741749-8090-10-S1-A16310.1186/1749-8090-10-S1-A163Meeting AbstractEvaluation of 17β-estradiol effects in mesenteric injury induced by occlusion of proximal descending aorta in male ratsde SousaPaulo Thales Rocha1FaloppaAna Cristina Breithaupt1CorreiaCristiano de Jesus1MenegatLauraSimãoRaifd Restivo1ArmstrongRobertoJr1FerreiraSueli Gomes1FiorelliAlfredo Inácio1MoreiraLuiz Felipe Pinho1SannomiyaPaulina1Department of Cardiopneumology, Heart Institute (InCor) - University of Sao Paulo Medical School, Sao Paulo, 05403-000, Brazil20151612201510Suppl 1Proceedings of the WSCTS 25th Anniversary CongressVipin Zamvar and Leonie PostmaPublication charges for this supplement were funded by the WSCTS conference. The Supplement Editors declare no competing interests.A163A163Copyright © 2015 de Sousa et al.2015de Sousa et al.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.19-22 September 2015World Society of Cardiothoracic Surgeons 25th Anniversary Congress, EdinburghEdinburgh, UKBackground/Introduction

Acute mesenteric ischemia is a life-threatening emergency with overall mortality ranging from 60% to 80%, and this survival rate has not improved substantially in recent decades. In surgical aortic reconstruction, occlusion of the aorta affects various organs through the ischemia reperfusion injury. Among these organs, the intestine is probably the most affected one. Several studies have proposed that oestradiol has a beneficial effect in the course of the inflammatory lesion.

Aims/Objectives

This study aims to investigate the role of 17β-estradiol on mesenteric microcirculation after the occlusion of the descending aorta in male rats.

Method

Male Wistar rats underwent mesenteric ischaemia by placing a Fogarty catheter® in the aorta, that remained occluded during 15 minutes, followed by reperfusion up to 2 hours. Rats were divided into four groups: (1) rats that underwent surgical manipulation only (SHAM, n = 9); (2) rats submitted to ischaemia-reperfusion injury (I/R, n = 11); (3) rats treated with 17β-estradiol (E2, 280 μg/kg, iv) 30 minutes before I/R (pre-E2 I/R, n = 16); (4) rats treated with 17β-estradiol (E2, 280 μg/kg, iv) 15 minutes after the ischaemia induction (post-E2 I/R, n = 16)). Mesenteric perfusion was measured by intravital microscopy. Expression of eNOS was evaluated by immunohistochemistry and RT-PCR.

Results

There was 40% decrease in the number of perfused small vessels (<30 μm diameter) in the group I/R compared to SHAM (p = 0.0386) associated with a reduction on endothelial nitric oxide synthase (eNOS) expression (p = 0,0126). The pre-E2 I/R treatment improved mesenteric perfusion (p = 0.0540) and eNOS expression (p < 0.0001) to levels attained in SHAM rats. The post-E2 I/R treatment normalised eNOS expression to reference levels. There were no differences in eNOS gene expression amongst groups.

Discussion/Conclusion

Data presented suggest that either pre-treatment or post-treatment with 17β-estradiol enhances expression of eNOS on endothelial microvessels, improving mesenteric perfusion. 17β-estradiol treatment may be considered as an alternative to prevent major organs injury induced by aortic surgical procedures. Financial Support: 2013/02563-2 FAPESP