Plasma malondialdehyde testing is used to assess oxidative damage to cell lipids.
Oxidizing agents can alter the structure of lipids, creating peroxides and ultimately the formation of malondialdehyde (malonic dialdehyde, MDA). Malondialdehyde is an organic substance that results from the peroxidation of lipids and more specifically, from the action of oxygen free radicals on polyunsaturated fatty acids. Malondialdehyde is a toxic substance for cells because it forms covalent bonds with various cellular proteins and also has an effect on cell DNA causing mutations. The measurement of malondialdehyde is a measure of the effect of reactive oxygen species on lipids and thus an assessment of the body's oxidative stress. Cell membrane lipid peroxidation leads to loss of fluidity and elasticity, reduced cell function, and can even lead to cell rupture and cell death. Lipid peroxidation can contribute to the pathology of many diseases including atherosclerosis, diabetes, and Alzheimer's disease.
Malondialdehyde is measured in plasma by the TBARS method, i.e. as substances that react with thiobarbituric acid (Thiobarbituric Acid Reactive Substances, TBARS). TBARS measurement is widely used as a relatively simple and accurate method of determining the concentration of peroxidized lipids in various biological fluids, including serum, plasma, urine, etc.
Serum or plasma TBARS levels increase with age and may be affected by vitamin C and E intake, saturated dietary fat intake, and serum triglyceride levels.
Plasma TBARS levels have been associated with a number of pathological conditions such as cardiovascular diseases, ischemia and myocardial reperfusion, sepsis, preeclampsia, chronic obstructive pulmonary disease, chronic pancreatitis, chronic kidney disease, brain disorders, and bipolar disorders. Smoking increases plasma TBARS.
TBARS testing has also been used to assess cells' sensitivity to oxidative stress as well as to test the antioxidant properties of food.