Superoxide Dismutase as a Gene Therapy: Future Perspectives

In recent years there is an upsurge in the areas related to newer developments in prevention of disease especially the role of free radicals and antioxidants. So it will be pertinent to examine the possible role of ‘free radicals’ in disease and ‘antioxidants’ in its prevention, especially the current status of the subject matter and future prospects. Numerous short-lived and highly reactive oxygen species (ROS) such as superoxide (O2 − ), hydroxyl radical,and hydrogen peroxide are continuously generated in vivo. Depending upon concentration, location, and intracellular conditions, ROS can cause toxicity or act as signaling molecules. The cellular levels of ROS are controlled by antioxidant enzymes and small-molecule antioxidants. As major antioxidant enzymes, superoxide dismutases (SODs), including copper–zinc superoxide dismutase (Cu-ZnSOD), manganese superoxide dismutase (Mn-SOD), and extracellular superoxide dismutase, plays a crucial role in scavenging O2 − . Antioxidants, capable of neutralizing free radicals or their actions, act at different stages. They act at the levels of prevention, interception and repair. Preventive antioxidants attempt to stop the formation of ROS. These include superoxide dismutase (SOD) that catalyses the dismutation of superoxide to H2O2 and catalase that breaks it down to water (Sies, 1996). Interception of free radicals is mainly by radical scavenging, while at the secondary level scavenging of peroxyl radicals are affected. The effectors include various antioxidants like vitamins C and E, glutathione, other thiol compounds, carotenoids, flavonoids, etc. At the repair and reconstitution level, mainly repair enzymes are involved.