Virus primed airway epithelial cells extracellular vesicles alter primary rat cardiomyocyte function and metabolism

Introduction Extracellular vesicles (EVs) are increasingly recognized as mediators of intercellular communication during viral infections. This study investigated whether EVs secreted from airway epithelial cells after stimulation with the SARS-CoV-2 receptor-binding domain (RBD) protein influence primary rat cardiomyocyte function. Methods EVs were isolated from conditioned medium by polymer-based precipitation and characterized by cryo-TEM and NTA. Primary cardiomyocyte cultures were prepared from neonatal Wistar rats (4–6 days) and validated by immunocytochemistry. EV uptake was assessed by SytoRNA labelling and fluorescence microscopy. Cardiomyocytes contractility was evaluated by analyzing video recordings with the Fiji plugin Myocyter. Cellular metabolism was determined using Seahorse assay, and ROS levels were measured with DCFHDA using a fluorescent reader. Results EVs displayed a lipid bilayer and were predominantly 130–150 nm diameter. Primary culture, mainly composed of cardiomyocytes, uptake EVs within 20h. RBD-EV exposure altered contractility by prolonging contraction duration, increasing amplitude, and reducing frequency. Seahorse assays showed decreased maximal respiration, while ROS levels remained unchanged. Conclusion Primary rat cardiomyocytes internalize airway epithelial cell-derived EVs stimulated by SARS-CoV-2 RBD and subsequently modify their contractility and metabolic activity. These findings indicate a potential EV-mediated mechanism contributing to virus-associated cardiac dysfunction.