Influence of early and late estrogen treatments in ovariectomized senescence accelerated (SAMP8) and resistant (SAMR1) female mice: a study of the mechanism of action in the carotid.

Author(s)

Tiago Januário da Costa

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2017-10-11

Examining board members

Maria Helena Catelli de Carvalho; Maria Luiza Morais Barreto de Chaves; Kátia de Angelis Lobo D'Avila; Carolina Demarchi Munhoz; Angelina Zanesco

• Advisor: Maria Helena Catelli de Carvalho

Abstract

Observational clinical trials and animal studies demonstrated that estrogen promote cardiovascular protection. However, there are controversies after randomized clinical trials. It has been suggested that there is a therapeutic window of opportunity timing hypothesis theory , which analyzes the early and late estrogen treatments in postmenopausal women. We evaluated the carotid function in ovariectomized senescence (SAMP8) and resistant (SAMR1) female mice treated with estrogen in mineral oil solution dose of 5 g/kg by subcutaneous injection every three days. In SAMR1 estrogen treatments promoted vasculoprotection. In SAMP8 early-onset estrogen treatment did not change the effect observed in the ovariectomy, however late-onset estrogen treatment increased the vasoconstriction to phenylephrine, the thromboxane production and the protein expression of ERα-36kDa, alternative splicing. Therefore, the effects of estrogen were not beneficial in aging, contributing to the development of cardio and cerebrovascular diseases due to alteration cerebral circulation. (AU)

• FAPESP's process: 13/19423-9 - Effects of hormonal treatment with estrogen on carotid function of senescent females: influence of epigenetic regulation.
• Grantee: Tiago Januário da Costa
• Support Opportunities: Scholarships in Brazil - Doctorate