Abstract P141: Cardiac TRH Partly Mediates Angiotensin II-induced Fibrotic and Hypertrophy Effects in "in vivo" and "in vitro" Models [Session Title: Angiotensin Action and Signaling/Renin Angiotensin System 1]

Cardiac TRH (cTRH) is overexpressed in the hypertrophied ventricle (LV) of the SHR. Additionally in vivo siRNA-TRH treatment induced downregulation of LV-TRH preventing cardiac hypertrophy and fibrosis demonstrating that TRH is involved in hypertrophic and fibrotic processes. Moreover, in a normal heart, the increase of LV TRH expression alone could induce structural changes where fibrosis and hypertrophy could be involved, independently of any other system alterations.Is well-known the cardiac hypertrophy/ fibrotic effects induced by AII, raising the question of whether specific LV cTRH inhibition might attenuates AII induced cardiac hypertrophy and fibrosis in mice.We challenged C57 mice with AII (osmotic pumps,14 days; 2 mg/kg) to induce cardiac hypertrophy vs saline. Groups were divided and , simultaneously to pump surgery, injected intracardiac with siRNA-TRH and siRNA-Con as its control. Body weight, water consume and SABP were measured daily.As expected, AII significantly increased SABP (p<0.05) in both groups treated , although cardiac hypertrophy (heart weight/body weight) was only evident in the group with the cardiac TRH system undamaged, suggesting that the cardiac TRH system function as a necessary mediator of the AII-induced hypertrophic effect.As hypothesized, we found an AII-induced increase of TRH (p<0.05) gene expression (real-t PCR) confirmed by immunofluorescence that was not observed in the group AII+siRNA-TRH demonstrating the specific siRNA treatm...
Source: Hypertension - Category: Cardiology Authors: Tags: Session Title: Angiotensin Action and Signaling/Renin Angiotensin System 1 Source Type: research