Angiotensin II in atrial structural remodeling: the role of Ang II/JAK/STAT3 signaling pathway.

Ang II/JAK/STAT3 signaling pathway is known to be involved in atrial remodeling associated with development and progression of atrial fibrillation. In the present study, we used in vivo animal model and human atrial specimens to further characterize the role of this pathway in the atrial structural remodeling. We observed an elevated level of Ang II in the atrial samples of AF patients. This increase in Ang II was accompanied by increased expression of collagens I and III, MMP1, MMP2 and elevated phosphorylation of STAT3. Using rat models, we demonstrated that Ang II infusion induced profound changes in the level of apoptosis, expression of collagen subtypes I and III, caspase-3, caspase-8, MMP1, MMP2 and redistribution of cytochrome C. The data further support the key role of Ang II in the development of AF and highlight the specific mechanisms and changes associated with this process.