Antioxidant Profile


Indications:

In this profile circulating levels of caeruloplasmin are assessed, along with the activity of four antioxidant enzymes. These measurements can be used as a guide to the preventative antioxidant activity of the blood, as well as the possible response to oxidative stress and to micronutrient deficiencies. In addition, vitamin E (alpha-tocopherol), alpha-carotene and beta-carotene are measured.

Most of the copper in plasma is present as the ferro-oxidase enzyme caeruloplasmin, which is a positive acute phase reactant and hence rises in concentration in the plasma during inflammation [1,2]. This process reflects the movement of copper from inside the cells into the extra-cellular fluid. The ferro-oxidase action of caeruloplasmin circulating in the serum is to catalyse the reaction:

4 Fe2+ + 4 H+ + O2 = 4 Fe3+ + 2 H2O,

thereby keeping available iron in the Fe(III) state, in which it can be incorporated into transferrin. This reaction also blocks the damaging effects of ferrous iron - Fe(II) - which can take part in Fenton reactions and cause propagation of reactive oxygen and reactive nitrogen species.

Every aerobic cell contains superoxide dismutase (SOD), which is required for the detoxification of the oxygen metabolite superoxide (O2-). Superoxide "leaks" from the mitochondrial electron transport chain, primarily at complex I (NADH-coenzyme Q) and to a lesser extent at complex II (succinate-coenzyme Q) and complex III (coenzyme QH2-cytochrome C reductase). The superoxide radical anion O2- - plays a central role in the development of oxidative stress since other reactive oxygen species appear to be derived from it. Copper (with zinc and manganese) is an essential component of SOD [3,4,5].

The seleno-enzyme glutathione peroxidase (GSHPx) catalyses the reduction of hydrogen peroxide to water, with the simultaneous conversion of reduced glutathione to oxidised glutathione. The origin of this H2O2 is primarily the lipid hydroperoxides released from membrane phospholipids by the action of phospholipase A2 during an inflammatory reaction. GSHPx thus de-toxifies this H2O2 by reducing it to water. Any deficiency in this de-toxification cycle puts the cell at risk from the potentially mutagenic effects of lipid hydroperoxides. In the antioxidant profile both red cell glutathione peroxidase (GSHPx-1) and plasma glutathione peroxidase (GSHPx-3) are measured, giving an estimate of both intracellular and extracellular activities of the enzyme [6,7,8,9].

Paraoxonase (PON-1) is a calcium-dependant esterase that circulates in plasma bound to high-density lipoprotein (HDL). PON-1 was originally identified by its activity in the metabolism of organophosphates such as paraoxon and thus serves to neutralise anti-cholinesterase insecticides in the body. But studies have confirmed that PON-1 is also an oxidant-sensitive enzyme which inhibits the atherogenic oxidation of LDL. Low PON-1 activity has been associated with a number of risk factors for coronary heart disease, including diabetes, hypercholesterolaemia and smoking [10,11,12].

Vitamin E is the generic term that refers to all substances having the biological activity of d-alpha-tocopherol. Alpha-tocopherol itself has the highest scavenging activity against lipid peroxyl radicals of all the nutritional antioxidants. The maintenance of its serum concentrations of depends in part on the action of alpha-tocopherol transfer protein, a secretion of the hepatocytes, to preferentially take up alpha-tocopherol from the portal blood, while other forms of vitamin E are more rapidly metabolized and excreted. [13,14]

Alpha and beta-carotene are among the best absorbed dietary carotenoids and hence present in the human plasma at relatively high concentrations. Both alpha- and beta-carotene have a pro-vitamin A function in the human [15,16].

Patient Instructions:

No nutritional supplements for 24 hours prior to testing

Clinical Indications:

Suspected oxidative stress states, including the effects of ageing, alcoholism, atherosclerosis, cancer, cataract, cystic fibrosis, diabetes, hepatitis, HIV infection, iron overload, pancreatitis, pre-eclampsia, pulmonary disease, rheumatoid arthritis, tooth and gum disease. Also suspected nutritional deficiencies, especially of copper and selenium

Datasheet:

antoxpr.pdf (Click to Download)

Sample Report:

rep-antioxidant-profile.pdf (Click to Download)

Sample Requirements:

2 x Yellow (Gold); 1 x Green (lithium heparin)

Postal Samples Acceptable:

Yes

References:

1. Cunningham JJ, Lydon MK, Emerson R et al. Low caeruloplasmin levels during recovery from major burn injury6: influence of open wound size and copper supplementation. Nutrition 1996;12:83-88.
2. Cauza E, Maier-Dobesberger T, Polli C et al. Screening for Wilson's disease in patients with liver diseases by ceruloplasmin. J Hepatol 1997;27:358-362.
3. McCord J, Fridovich I. Superoxide Dismutase: The First Twenty Years (1968-1988), Free Rad Biol Med 1988;5:363-371.
4. Arthur JR, Boyne R. Superoxide dismutase and glutathione peroxidase activities in neutrophils from selenium deficient and copper deficient cattle. Life Sciences 1985; 36:1569-1575.
5. Chesters JK, Arthur JR. Early biochemical defects caused by dietary trace element deficiencies. Nutrition Research Reviews 1988;1:39-56.
6. Michiels C, Raes M, Toussant O, Remacle J. Importance of Se glutathione peroxidase, catalase and Cu/Zn-SOD for cell survival against oxidative stress. Free Rad Biol Med 1994;17:235-248.
7. Ceballos-Picot I, Trivier J, Nicole A, et al. Age-correlated modifications of copper-zinc superoxide dismutase and glutathione-related enzyme activities in human erythrocytes. Clin Chem 1992;38:66-70.
8. Forstrom JW, Zakowski JJ, Tappel AL. Identification of the catalytic site of rat liver glutathione peroxidase as selenocysteine. Biochemistry 1978;17:2639-2644.
9. Benabdeslam H, Abidi H, Garcia I, Bellon G, Gilly R, Revol A. Lipid peroxidation and antioxidant defences in cystic fibrosis patients. Clin Chem Lab Med 1999;37:511-516.
10. Steinberg D, Parthasarathy S, Carew T et al. Beyond cholesterol; modifications of low density lipoprotein that increase atherogenecity. N Engl J Med 1998;320:933-937.
11. Mackness MI, Abbott CA, Arrol S et al. Protection of low density lipoprotein against oxidative modification by high density lipoprotein-associated paraoxonase. Atherosclerosis 1993;104:129-135.
12. Ferre N, Camps J, Fernandez-Ballart J et al. Regulation of serum paroxonase activity by genetic, nutritional, and lifestyle factors in the general population. Clin Chem 2003;49(9):1491-1497.
13. Brigelius-Flohe R, Kelly FJ, Salonen JT et al. The European perspective on vitamin E. Am J Clin Nutr 2002;76:703-716.
14. Miller NJ, Worrell PC, Jasniewicz KP. Erythrocyte tocopherol isomers in the investigation of vitamin E deficiency. Annals of Clinical Biochemistry 2010;47 Supplement 1:116.
15. Bendich A, Olson JA. Biological actions of carotenoids. FASEB J 1989:3;1927-32.
16. Miller NJ, Sampson J, Candeias LP, Bramley PM, Rice-Evans CA. Antioxidant activities of carotenoids and xanthophylls. FEBS Letters 1996;384:240-242.

For further details please contact the laboratory at: lab@xxxxbiolab.co.uk