Radiation-Induced Heart Disease: Potential Role for Molecular Hydrogen

Radiation-induced heart disease (RIHD) is a common complication of mediastinal radiotherapy. RIHD includes structural and functional abnormalities of the pericardium, coronary vessels, myocardium, valves, and conduction system. The underlying pathological mechanisms are complex, mainly related to endothelial cell injury, oxidative stress, and inflammation. Radiation can cause cardiomyocyte death, tissue fibrosis and ultimately may end up with heart failure. To overcome these complications, there is a need to look for specific therapeutic interventions, which are still missing. Molecular hydrogen (H2) has been recognized as a molecule with antioxidant, anti-inflammatory, and anti-apoptotic protective effects in different disease settings. In vitro as well as in vivo studies demonstrated that H2 exerted preventive or therapeutic effects on radiation-induced injury, including RIHD. H2 could be effective to mitigate RIHD through various mechanisms, e.g. selective neutralization of hydroxyl radicals, protection against inflammatory and apoptotic damage, anti-fibrotic and anti-hypertrophic effects, etc. More research is needed to elucidate further mechanisms of H2 action, and to verify the effectiveness of H2 therapy in clinical trials.