Understanding the benefits and harms of oxygen therapy

Excerpt

The Dr. Jekyll and Mr. Hyde character of oxygen (O₂) is well established [1], with O₂ the vital final electron acceptor within the respiratory chain, but also a strong oxidizer that leads to the formation of “reactive oxygen species” (ROS). Hyperoxia-related increases in ROS production are particularly pronounced during ischaemia/reperfusion (I/R) and hypoxia/reoxygenation [2]. This dichotomy also holds true for ATP synthesis and ROS formation. Approximately 2 % of mitochondrial O₂ consumption is directed towards ROS production, i.e., the more ATP produced, the more ROS generated [2]. ROS also share friend-and-foe characteristics, in that despite their toxic potential they are vital players in host defence systems and as signaling molecules [3]. …