AT1-receptor blockade: Protective effects of irbesartan in cardiomyocytes under hypoxic stress

Area of Science:

• Cardiology
• Pharmacology
• Molecular Biology

Background:

• Hypoxia triggers myocardial injury via inflammation and oxidative stress.
• The renin-angiotensin system (RAS) plays a key role in cardiovascular disease, with its inhibition showing cardioprotective effects.
• Activated RAS can directly promote inflammation and oxidative gene expression.

Purpose of the Study:

• To investigate the protective effects of irbesartan pre-treatment against hypoxia-induced injury in HL-1 cardiomyocytes.
• To analyze the impact of irbesartan on biomarkers of oxidative stress, inflammation, and cardiac injury, including brain natriuretic peptide (BNP).

Main Methods:

• HL-1 cardiomyocytes were pre-treated with irbesartan (10 and 100 μM) before exposure to 24 hours of hypoxia.
• Assessed superoxide dismutase (SOD) activity, catalase expression, peroxynitrite release, inducible nitric oxide synthase (iNOS) protein expression.
• Measured Toll-like receptors (TLRs)-2 and -4 mRNA, tumor necrosis factor-alpha (TNF-alpha) expression and activity, interleukin-17 (IL-17) expression, and BNP levels.

Main Results:

• 100 μM irbesartan significantly increased SOD activity (15%) and catalase expression (25%) compared to hypoxic cells.
• Irbesartan reduced peroxynitrite release (20%) and iNOS protein expression (50%).
• It demonstrated anti-inflammatory effects by reducing TLRs-2 and -4 mRNA, TNF-alpha (20%), and increasing IL-17 (40%). BNP levels were also reduced concentration-dependently.

Conclusions:

• Irbesartan, an AT1 receptor antagonist, exerts a protective role against in vitro hypoxic cardiac injury.
• Pre-treatment with irbesartan mitigates oxidative stress and inflammation in cardiomyocytes under hypoxic conditions.
• These findings support the potential cardioprotective role of irbesartan in managing hypoxia-related cardiac damage.