Oxidative Stress Associated Diseases and Conditions
Oxidative stress is a physiological condition that occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the body’s antioxidant defenses. While ROS play roles in normal cell signaling and immune responses, excessive levels can damage lipids, proteins, and DNA, contributing to the development of numerous diseases.
1. Sources of Reactive Oxygen Species (ROS)
• Endogenous Sources: Mitochondrial electron transport chain leakage, NADPH oxidases, peroxisomal metabolism, inflammatory cell activity.
• Exogenous Sources: Pollution, radiation, cigarette smoke, certain drugs, heavy metals, and high-fat/high-sugar diets.
2. Mechanisms of Oxidative Damage
• Lipid Peroxidation: ROS attack polyunsaturated fatty acids in cell membranes, producing malondialdehyde and 4-hydroxynonenal.
• Protein Oxidation: Oxidation of amino acid side chains, formation of protein carbonyls, and cross-linking.
• DNA Damage: Base modifications (e.g., 8-oxo-dG), strand breaks, mutations.
3. Antioxidant Defense Systems
• Enzymatic Antioxidants: Superoxide dismutase (SOD), catalase, glutathione peroxidase, peroxiredoxins.
• Non-Enzymatic Antioxidants: Vitamin C, Vitamin E, glutathione, carotenoids, flavonoids.
4. Diseases and Conditions Associated with Oxidative Stress
| Disease / Condition | Role of Oxidative Stress | Notes / Evidence |
| Atherosclerosis | Oxidized LDL triggers inflammation and plaque formation in arteries. | Linked with cardiovascular events; antioxidants show partial protective effects. |
| Diabetes Mellitus | ROS contribute to beta-cell damage and insulin resistance. | Oxidative stress worsens diabetic complications. |
| Neurodegenerative Diseases | ROS damage neurons and promote protein aggregation. | Alzheimer’s, Parkinson’s, ALS all linked. |
| Cancer | ROS can cause mutations and promote tumor progression. | Dual role: low levels may promote growth, high levels induce apoptosis. |
| Chronic Kidney Disease | ROS contribute to glomerular damage and fibrosis. | Biomarkers like 8-oxo-dG elevated in CKD patients. |
| Aging | Cumulative oxidative damage contributes to functional decline. | Free radical theory of aging partially supported. |
6. Prevention and Management
• Lifestyle: Balanced diet rich in antioxidants, regular exercise, avoiding smoking and excessive alcohol.
• Pharmacological: Antioxidant supplements, drugs targeting ROS production (e.g., NADPH oxidase inhibitors).
• Medical Monitoring: Periodic biomarker testing for high-risk individuals.