Deepak Bhatt, M.D., M.P.H.
Executive Director of Interventional Cardiovascular Programs
n/a, United States
Disclosure information not submitted.
Preston Mason, PhD
Professor
Brigham & Women's Hospital
Beverly, Massachusetts, United States
Disclosure information not submitted.
Title: Eicosapentaenoic Acid Increases Endothelial Function and Heme Oxygenase-1 in Pulmonary Inflammation
Introduction: Endothelial cell (EC) dysfunction results in reduced nitric oxide (NO) bioavailability leading to inflammation and increased susceptibility to infectious agents. Heme oxygenase-1 (HO-1) produces potent antioxidant and anti-inflammatory products including carbon monoxide. SARS-CoV-2 and influenza affect ECs in multiple vascular beds, including pulmonary tissue. The omega-3 fatty acid eicosapentaenoic acid (EPA) and its metabolites preserve EC function in a manner that may contribute to reduced incident cardiovascular events (REDUCE-IT). Currently, EPA is being tested in patients with or at risk for COVID-19. This study tested the effects of EPA on NO and peroxynitrite (ONOO−) release under conditions of inflammation using lipopolysaccharide (LPS) and the cytokine IL-6. We also measured expression of HO-1 after cell challenge with IL-6.
Methods: Human lung microvascular endothelial cells (HMVEC-L) were pretreated with vehicle or EPA (40 µM) in 2% FBS for 2 h, then challenged with either IL-6 (12 ng/ml) or LPS (200 ng/ml) for 24 h. Cells (including untreated controls) were stimulated with calcium ionophore to measure maximum production of NO and peroxynitrite (ONOO−) using tandem porphyrinic nanosensors. Proteomic analysis was performed using LC/MS to assess relative expression levels. Only significant (p < 0.05) changes in protein expression between treatment groups >1-fold were analyzed.
Results: HMVEC-L challenged with LPS and IL-6 showed a pronounced loss of NO release by 22% (p < 0.01) and 18% (p < 0.01), respectively, concomitant with an increase in ONOO− by 28% (p < 0.01) and 26% (p < 0.01), respectively. As a result, the [NO]/[ONOO−] ratio, a marker of eNOS coupling efficiency, decreased by 39% (p < 0.001) and 35% (p < 0.001) with LPS and IL-6, respectively. However, EPA increased this ratio by 39% (p < 0.01) in both LPS and IL-6 treated cells. EPA also caused a 5.7-fold (p = 4.4 × 10-38) increase in expression of HO-1 with IL-6.
Conclusions: These findings indicate that EPA improves NO bioavailability and reduces nitroxidative stress in pulmonary ECs during inflammation with LPS or IL-6. These studies indicate a protective effect of EPA on pulmonary ECs that may reduce inflammatory activation during sepsis, influenza, or advanced COVID-19 that may mediate many aspects of multiorgan system failure.