Apelin Is a Negative Regulator of Angiotensin II-Mediated Adverse Myocardial Remodeling and Dysfunction
HYPERTENSION
Authors: Zhang, Zhen-Zhou; Wang, Wang; Jin, Hai-Yan; Chen, Xueyi; Cheng, Yu-Wen; Xu, Ying-Le; Song, Bei; Penninger, Josef M.; Oudit, Gavin Y.; Zhong, Jiu-Chang
Abstract
The apelin pathway has emerged as a critical regulator of cardiovascular homeostasis and disease. However, the exact role of pyr1-apelin-13 in angiotensin (Ang) II-mediated heart disease remains unclear. We used apelin-deficient (APLN(-/y)) and apolipoprotein E knockout mice to evaluate the regulatory roles of pyr1-apelin-13. The 1-year aged APLN(-/y) mice developed myocardial hypertrophy and dysfunction with reduced angiotensin-converting enzyme 2 levels. Ang II infusion (1.5 mg kg(-1) d(-1)) for 4 weeks potentiated oxidative stress, pathological hypertrophy, and myocardial fibrosis in young APLN(-/y) hearts resulting in exacerbation of cardiac dysfunction. Importantly, daily administration of 100 mu g/kg pyr1-apelin-13 resulted in upregulated angiotensin-converting enzyme 2 levels, decreased superoxide production and expression of hypertrophy- and fibrosis-related genes leading to attenuated myocardial hypertrophy, fibrosis, and dysfunction in the Ang II-infused apolipoprotein E knockout mice. In addition, pyr1-apelin-13 treatment largely attenuated Ang II-induced apoptosis and ultrastructural injury in the apolipoprotein E knockout mice by activating Akt and endothelial nitric oxide synthase phosphorylation signaling. In cultured neonatal rat cardiomyocytes and cardiofibroblasts, exposure of Ang II decreased angiotensin-converting enzyme 2 protein and increased superoxide generation, cellular proliferation, and migration, which were rescued by pyr1-apelin-13, and Akt and endothelial nitric oxide synthase agonist stimulation. The increased superoxide generation and apoptosis in cultured cardiofibroblasts in response to Ang II were strikingly prevented by pyr1-apelin-13 which was partially reversed by cotreatment with the Akt inhibitor MK2206. In conclusion, pyr1-apelin-13 peptide pathway is a negative regulator of aging-mediated and Ang II-mediated adverse myocardial remodeling and dysfunction and represents a potential candidate to prevent and treat heart disease.
Transplantation of Human Amniotic Membrane over the Liver Surface Reduces Hepatic Fibrosis in a Cholestatic Model in Young Rats
STEM CELLS INTERNATIONAL
Authors: Garrido, M.; Escobar, C.; Zamora, C.; Rejas, C.; Varas, J.; Cordova, C.; Papuzinski, C.; Parraga, M.; San Martin, S.; Montedonico, S.
Abstract
Purpose. Biliary atresia precedes liver cirrhosis and liver transplantation. Amniotic membrane (AM) promotes tissue regeneration, inhibits fibrosis, and reduces inflammation. Here, we test amniotic membrane potential as a therapeutic tool against cholestatic liver fibrosis. Methods. Three groups of rats were used: sham surgery (SS), bile duct ligature (BDL), and bile duct ligature plus human amniotic membrane (BDL + AM). After surgery, animals were sacrificed at different weeks. Biochemical and histopathological analyses of liver tissue were performed. Collagen was expressed as a percentage of total liver tissue area. qPCR was performed to analyse gene expression levels of transforming growth factor-beta 1 (Tgfb1) and apelin (Apln). Statistical analysis performed considered p < 0 05 was significant. Results. Groups undergoing BDL developed cholestasis. Biochemical markers from BDL + AM group improved compared to BDL group. Ductular reaction, portal fibrosis, and bile plugs were markedly reduced in the BDL + AM group compared to BDL group. Collagen area in BDL + AM group was statistically decreased compared to BDL group. Finally, expression levels of both Apln and Tgfb1 mRNA were statistically downregulated in BDL + AM group versus BDL group. Conclusion. AM significantly reduces liver fibrosis in a surgical animal model of cholestasis. Our results suggest that AM may be useful as a therapeutic tool in liver cirrhosis.