How Oxygen Damages the Adult Heart

Previously, scientists at the University of Texas Southwestern Medical Center (Texas, USA) discovered that the newborn animal heart can heal itself completely, whereas the adult heart lacks this ability. Hesham Sedak now reveal why the heart loses its incredible regenerative capability in adulthood.  While  a major function of the heart is to circulate oxygen-rich blood throughout the body, oxygen is a highly reactive, nonmetallic element and oxidizing agent that readily forms toxic substances with many other compounds. This latter property has now been found to underlie the loss of regenerative capacity in the adult heart. Specifically, the oxygen-rich atmosphere experienced immediately after birth causes heart cells build up mitochondria – the powerhouse of the cell – which results in increased oxidization. The mass production of oxygen radicals by mitochondria damages DNA and, ultimately, causes cell cycle arrest.  Submitting that: “These findings uncover a protective mechanism that mediates cardiomyocyte cell-cycle arrest in exchange for utilization of oxygen-dependent aerobic metabolism,” the study authors propose that: “Reduction of mitochondrial-dependent oxidative stress should be an important component of cardiomyocyte proliferation-based therapeutic approaches.”