Vitamin E - erythrocytes


Indications:

Serumalpha- and gama-tocopherol concentrations are commonly used as markers of vitamin E status, but in certain conditions may have a limited diagnostic value. For example, the serum level in patients suffering from ataxia with vitamin E deficiency (AVED syndrome) can fluctuate rapidly during supplementation, rather than achieving a steady state. The erythrocyte tocopherol content is less susceptible to fluctuations after supplementation and is therefore a possible marker of tissue vitamin E status.

The maintenance of serum concentrations of alpha-tocopherol normally depends on the action of alpha-tocopherol transfer protein, secreted by hepatocytes, to preferentially take up alpha-tocopherol from the portal blood, while other forms of vitamin E are more rapidly metabolized and excreted. As a result, blood and cellular concentrations of other vitamin E isomers are lower than those of alpha-tocopherol and have been the subjects of less research.

The erythrocyte tocopherol content is thus a possible marker of tissue vitamin E status in subjects with gross lipid abnormalities and also in subjects suspected of having AVED syndrome, in which there is an abnormality of alpha-tocopherol transfer protein.

Patient Instructions:

Avoid vitamin E containing supplements for 24-48 hours prior to testing

Clinical Indications:

Erythrocyte tocopherol measurement has a role in the investigation of difficult cases of vitamin E deficiency. There is a good correlation between between serum and erythrocyte gamma-tocopherol, but not between serum and erythrocyte alpha-tocopherol, which reflects the important role of alpha-tocopherol transfer protein in the maintenance of body vitamin E status. There are no previous reports in the scientific literature of the erythrocyte /plasma gamma -tocopherol ratio.

Our results for vitamin E-replete subjects suggest a range for the erythrocyte /plasma a-tocopherol ratio of 0.03-0.19 (mean value 0.10), which is lower than that of previous investigators. Our results also suggest a range for the erythrocyte /plasma gamma -tocopherol ratio of 0.11-0.67 (mean value 0.28), which underlines the different physiological mechanisms for the tissue handling of tocopherol isomers.

Datasheet:

rbctocopherol.pdf (Click to Download)

Sample Requirements:

Green (lithium heparin) and gold (clotted blood sample) capped blood cllection tubes - must reach Biolab within 24 hours of collection

Postal Samples Acceptable:

Yes

References:


1. 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.
2. Chow KC, Distribution of tocopherols in human plasma and red blood cells. Am J Clin Nutr 1975; 28:756-760.
3. Mino M, Kitagawa M, Nakagawa S. Red blood cell tocopherol concentrations in a normal population of Japanese children and premature infants in relation to the assessment of vitamin E status. Am J Clin Nutr 1985;41: 631-638.
4. Lehmann J, Rao DD, Canary JJ, Judd JT. Vitamin E and relationships among tocopherols in human plasma, platelets, lymphocytes, and red blood cells. Am J Clin Nutr 1988; 47:470-474.
5. Thurnam DI, Smith E, Flora PS. Concurrent liquid chromatographic assay of retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene and beta-cryptoxanthin. Clin Chem 1988;34:377-381.

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