Liver Degenerative Disease
Free-Radical Damage and Lipid Peroxidation
Oxidative damage from the production of free radicals has far-reaching consequences. Lipid peroxidation describes fats that have been chemically damaged by oxygen free radicals. Cell membranes consist mainly of layers of phospholipids. As free radicals attack the cell membrane, injury and eventual death to the cell occur due to DNA strand breakage. DNA is the cellular blueprint required for replication. Oxidative stress also affects circulating lipids in the body including cholesterol, 80% of which is produced in the liver. Peroxidized cholesterol has been shown to damage arteries, leading to atherosclerosis; a growing body of evidence supports a role for lipid peroxidation in the continued development of liver damage.
While cell damage in the human liver is likely multifactorial, free radicals have been implicated in a variety of liver diseases, particularly in the presence of iron overload, ethanol consumption, and ischemia/reperfusion injury, either initiating or perpetuating liver damage. Additionally, free radical-initiated lipid peroxidation appears to play a role in hepatic fibrogenesis (Britton 1994). The role of free radicals is significant in toxic liver injury often induced by drugs and chemicals. Damage is first caused by the toxin itself and then is continued when the toxin is metabolized by the liver (Feher 1992).