Attenuation of atrial remodeling by aliskiren via affecting oxidative stress, inflammation and PI3K/Akt signaling pathway.

Abstract

INTRODUCTION:

Atrial fibrillation (AF) is the most common type of arrhythmia. Atrial remodeling is a major factor to the AF substrate. The purpose of the study is to explore whether aliskiren (ALS) has a cardioprotective effect and its potential molecular mechanisms on atrial remodeling.

METHODS:

In acute experiments, dogs were randomly assigned to Sham, Paced and Paced+aliskiren (10 mg kg-1) (Paced+ALS) groups, with 7 dogs in each group. Rapid atrial pacing (RAP) was maintained at 600 bpm for 2 h for paced and Paced+ALS groups and atrial effective refractory periods (AERPs), inducibility of AF (AFi) and average duration time (ADT) were measured. In chronic experiments, there were 5 groups: Sham, Sham+ALS, Paced, Paced+ALS and Paced+ALS+PI3K antagonist wortmannin (WM) (70 μg kg-1 day-1). RAP at 500 beats/min was maintained for 2 weeks. Inflammation and oxidative stress indicators were measured by ELISA assay, echocardiogram and pathology were used to assess atrial structural remodeling, phosphatidylinositol 3-hydroxy kinase/protein kinase B (PI3K/Akt) signaling pathways were studied by RT-PCR and western blotting to evaluate whether the cardioprotective effect of ALS works through PI3K/Akt signaling pathway.

RESULTS:

The electrophysiological changes were observed after 2-h pacing. The AERP shortened with increased AFi and ADT, which was attenuated by ALS (P < 0.05). After pacing for 2 weeks, oxidative stress and inflammation markers in the Paced group were significantly higher than those in the Sham group (P < 0.01) and were reduced by ALS treatment (P < 0.01). The reduced level of antioxidant enzymes caused by RAP was also found to be elevated in ALS-treated group (P < 0.01). The results of pathology and echocardiography showed that RAP can cause atrial enlargement, fibrosis (P < 0.01), and were attenuated in ALS treatment group. The PI3K/Akt signaling pathway were downregulated induced by RAP. ALS could upregulate the PI3K/Akt pathway expression (P < 0.05). Furthermore, the cardioprotective effects in structural remodeling of ALS were suppressed by WM.

CONCLUSIONS:

ALS may offer cardioprotection in RAP-induced atrial remodeling, which may partly be ascribed to its anti-inflammatory and anti-oxidative stress action and the regulation of PI3K/Akt signaling pathway.

• Authors: Zhiqiang Zhao, Ruiling Li, Xinghua Wang, Jian Li, Meng Yuan, Enzhao Liu, Tong Liu, Guangping Li
• Journal: Cardiovascular drugs and therapy (Cardiovasc Drugs Ther) Vol. 35 Issue 3 Pg. 587-598 (06 2021) ISSN: 1573-7241 [Electronic] United States
• PMID: 32462265 (Publication Type: Journal Article)

Chemical References

• Amides
• Fumarates
• Inflammation Mediators
• aliskiren
• Wortmannin

Topics

• Amides (pharmacology)
• Animals
• Atrial Remodeling (drug effects)
• Dogs
• Echocardiography
• Female
• Fumarates (pharmacology)
• Inflammation Mediators (metabolism)
• Male
• Oxidative Stress (drug effects)
• Phosphatidylinositol 3-Kinases (metabolism)
• Random Allocation
• Signal Transduction (drug effects)
• Wortmannin (pharmacology)