A novel acute microphysiological model of endothelial dysfunction rescued by green laser photobiomodulation treatment

Introduction: Cardiovascular diseases (CVDs) remain a leading cause of mortality, fundamentally associated with endothelial dysfunction. Photobiomodulation (PBM) has been shown to modulate endothelial functions, but a lack of precise mechanisms has prevented robust clinical protocols that motivated the current study. Methods: Endothelial progenitor cells were grown and subjected to a dose-dependent Angiotensin II and centrifugation-induced shear-related mechanical stress. PBM treatments were carried out using five wavelengths: 449 (blue), 532 (green), 588 (yellow), 660 (red), and 802 (infrared) nm at low, moderate and high doses. Harmonized PBM using wavelength specific photon energy (photonic fluence) and Einstein dosing were employed at constant target surface irradiance of 10 mW/cm² and varying treatment times. Cell metabolic viability with AlamarBlue assay, reactive oxygen species (ROS – H₂O₂) generation with Amplex Red assay, and Nitric Oxide (NO) production with Griess assay were assessed. Data was analyzed using one-way or two-way ANOVA according to the experimental designs (p < 0.05). Results: Endothelial dysfunction induced by a combination of 10 µM Ang-II and centrifugation significantly reduced cell metabolic viability (n = 4, p = 0.0018, 95% CI = 8359,451 – 41,778,754), decreased ROS (H₂O₂) levels (n = 4, p = 0.0178, 95% CI = 30,462 – 286,175) and reduced NO (n = 4, p = 0.0123, 95% CI = 0.0530 – 0.2636) compared to controls. PBM treatments (green, 532 nm, 10 mW/cm², 225 s, 1.10 ɇ) most prominently (n = 4, p = 0.0012) improved endothelial metabolic viability. PBM treatment also significantly (n = 4, p = 0.0119, 95% CI = -406,297 – -57,963) elevated ROS (H₂O₂) levels within 15 min and recovered NO expression significantly (n = 4, p = 0.0446, 95% CI = -0.2144 – 0.0038) compared to controls. Conclusion: PBM treatments successfully improved acute endothelial dysfunction markers, suggesting a mechanistically rationalized clinical protocol is feasible. Further mechanistic, in vivo and clinical studies could establish PBM as a non-pharmacological adjunctive therapeutic approach in safe and effective CVD management.