Assay of erythrocyte membrane fatty acids. Effects of storage time at low temperature

The study of the stability of saturated mono-, or polyunsaturated fatty aci ds, both esterified and not esterified, in plasma, circulating cells, and t issues is extremely important to validate the use of biological samples sto red at low temperature in "biological banks", which are used for experiment al, observational, dietary, or pharmacological studies. Since red blood cel ls are easily accessible cells, they are used as a marker of less-accessibl e tissues, especially in large-scale epidemiological studies. Data from the literature suggest that the addition of an antioxidant and the freezing of red blood cells do not cause any variation in the fatty acid composition f or a period of 2-6 months up to 1 year. We evaluated the fatty acid concent ration in red blood cells isolated from venous blood samples of one subject , preserved with butylated hydroxytoluene and Nz and stored at -80 degreesC for up to 2 years. Erythrocytes of venous samples of six subjects stored a t -20 degreesC for 6 months without butylated hydroxytoluene and in the pre sence of air were used for comparison purposes. Our data demonstrate that a long storage time (2 years) does not significantly influence the erythrocy te fatty acid concentration when using very low temperatures (-80 degreesC) and antioxidants (butylated hydroxytoluene) in the presence of N-2.