BACKGROUND & AIMS: Angiotensin II (ANG II) has profibrotic actions in the heart and kidney, whereas blockade of the renin angiotensin system (RAS) attenuates injury. This study examines whether the RAS is present in the liver and examines its regulation in the bile duct-ligation model of hepatic fibrogenesis. METHODS: Sham-operated and bile duct-ligated (BDL) Sprague-Dawley rats were studied. Gene and protein expression of hepatic renin, angiotensinogen, angiotensin-converting enzyme (ACE), and the angiotensin receptors AT1 and AT2 were assessed using real-time reverse-transcription polymerase chain reaction, in vitro autoradiography, and immunohistochemistry. RESULTS: Angiotensinogen and renin messenger RNA were detected in sham liver but were not increased following BDL. Angiotensinogen protein was widely distributed in hepatocytes in both normal and injured livers, but in BDL livers, it was also expressed within areas of active fibrogenesis. Both ACE and AT1 receptor genes were up-regulated following BDL. The low level of ACE activity in sham animals was significantly increased in areas of active fibrogenesis in BDL livers. The AT1 receptor was present in both normal and diseased liver parenchyma, with increased AT1 receptor binding seen in fibrotic areas in the diseased liver. The AT2 receptor gene was not detected in normal or diseased liver. CONCLUSIONS: Key elements of the RAS are present in normal liver tissue, and there is major up-regulation of the system in the bile duct-ligated liver. These findings are in keeping with recent experimental studies that have demonstrated antifibrotic effects of RAS blockade in the bile duct-ligated liver.
BACKGROUND & AIMS:Angiotensin II (ANG II) has profibrotic actions in the heart and kidney, whereas blockade of the renin angiotensin system (RAS) attenuates injury. This study examines whether the RAS is present in the liver and examines its regulation in the bile duct-ligation model of hepatic fibrogenesis. METHODS: Sham-operated and bile duct-ligated (BDL) Sprague-Dawley rats were studied. Gene and protein expression of hepatic renin, angiotensinogen, angiotensin-converting enzyme (ACE), and the angiotensin receptors AT1 and AT2 were assessed using real-time reverse-transcription polymerase chain reaction, in vitro autoradiography, and immunohistochemistry. RESULTS:Angiotensinogen and renin messenger RNA were detected in sham liver but were not increased following BDL. Angiotensinogen protein was widely distributed in hepatocytes in both normal and injured livers, but in BDL livers, it was also expressed within areas of active fibrogenesis. Both ACE and AT1 receptor genes were up-regulated following BDL. The low level of ACE activity in sham animals was significantly increased in areas of active fibrogenesis in BDL livers. The AT1 receptor was present in both normal and diseased liver parenchyma, with increased AT1 receptor binding seen in fibrotic areas in the diseased liver. The AT2 receptor gene was not detected in normal or diseased liver. CONCLUSIONS: Key elements of the RAS are present in normal liver tissue, and there is major up-regulation of the system in the bile duct-ligated liver. These findings are in keeping with recent experimental studies that have demonstrated antifibrotic effects of RAS blockade in the bile duct-ligated liver.
Authors: Kai Y Mak; Ruth Chin; Sharon C Cunningham; Miriam R Habib; Joseph Torresi; Alexandra F Sharland; Ian E Alexander; Peter W Angus; Chandana B Herath Journal: Mol Ther Date: 2015-05-25 Impact factor: 11.454
Authors: Ramon Bataller; Robert F Schwabe; Youkyung H Choi; Liu Yang; Yong Han Paik; Jeffrey Lindquist; Ting Qian; Robert Schoonhoven; Curt H Hagedorn; John J Lemasters; David A Brenner Journal: J Clin Invest Date: 2003-11 Impact factor: 14.808
Authors: Yong-Han Paik; Jonghwa Kim; Tomonori Aoyama; Samuele De Minicis; Ramon Bataller; David A Brenner Journal: Antioxid Redox Signal Date: 2014-01-24 Impact factor: 8.401
Authors: Jaclyn H Neo; Eleanor I Ager; Peter W Angus; Jin Zhu; Chandana B Herath; Christopher Christophi Journal: BMC Cancer Date: 2010-04-10 Impact factor: 4.430
Authors: Regina Maria Pereira; Robson Augusto Souza dos Santos; Filipi Leles da Costa Dias; Mauro Martins Teixeira; Ana Cristina Simões e Silva Journal: World J Gastroenterol Date: 2009-06-07 Impact factor: 5.742
Authors: Jaroslav Pavel; José A Terrón; Julius Benicky; Alicia Falcón-Neri; Amita Rachakonda; Tadashi Inagami; Juan M Saavedra Journal: Regul Pept Date: 2009-09-17