EPA and DHA Levels in Whole Blood Decrease More Rapidly when Stored at −20 °C as Compared with Room Temperature, 4 and −75 °C

Abstract

High-throughput n-3 fatty acid profiling is enabled by collection techniques such as venous whole blood and fingertip prick (FTP) sampling, but the resulting increased sample numbers increases storage demand. Highly unsaturated fatty acids (HUFA) in erythrocytes are susceptible to oxidation, but this tendency is poorly characterized in venous and FTP whole blood. Presently, whole blood samples with low and high n-3 content collected with ethylenediaminetetraacetic acid were stored on chromatography paper with and without BHT pre-treatment for up to 180 days at different temperatures (room, 4, -20, -75 °C). Whole blood prepared with heparin and BHT and stored in cryovials was also examined. Eicosapentaenoic acid (EPA, 20:5n-3) + docosahexaenoic acid (DHA, 22:6n-3) is relatively stable when stored at -75 °C under various conditions but rapidly decreases in whole blood when stored at -20 °C. At -20 °C, BHT + heparin prepared whole blood can prevent decreases in cryovials up to 180 days but BHT only slows the decreases on chromatography paper. Surprisingly, whole blood stored at 4 °C and room temperature was less susceptible to decreases in EPA + DHA as compared with -20 °C storage. Assessments of n-3 blood biomarkers indicate the % n-3 HUFA in total HUFA was more stable as compared with the sum of the relative % of EPA + DHA. In conclusion, FTP and venous whole blood for fatty acid analysis should be stored at -75 °C whenever possible. In the absence of -75 °C storage conditions, BHT should be added and 4 °C or room temperature appear to be better alternatives to -20 °C.

Der HS-Omega 3 Index®: klinische Wertigkeit standardisierter Fettsäureanalytik

“…nach der Bestimmung eines Blutbildes aus venösem Blut noch vorhanden ist. Die Fettsäurezusammensetzung von Erythrozyten ist bei Umgebungstemperatur mindestens eine Woche stabil, weshalb der Versand der Proben unproblematisch ist [7,8]. Bei -80°C ist die Fettsäurezusammensetzung der Erythrozyten über viele Jahre stabil, während sie sich bei -20°C schon nach wenigen Tagen verändert (7,8).…”

Microwave Energy Increases Fatty Acid Methyl Ester Yield in Human Whole Blood Due to Increased Sphingomyelin Transesterification

“…Data are presented as nmol fatty acid per 100 μL blood, mean ± SD, n = 4 SFA saturated fatty acid, MUFA monounsaturated fatty acid, PUFA polyunsaturated fatty acid and HUFA highly unsaturated fatty acid of analysis. We have previously shown that storage of the whole blood samples under these conditions will not significantly affect the fatty acid profile for up to 6 months [13], and all analyses were performed within 3 months of storage. For analysis, whole blood samples were removed from storage and allowed to thaw on ice.…”

“…Aliquots (25 μL) of the whole blood were applied to pre-washed chromatography strips as described previously [13] and allowed to dry in air for approximately 30 min. DBS were then transesterified by the 5-min, 30-W microwave method or 3 h standard 1 % H 2 SO 4 method as previously described, or for 1 h at 95 °C with 1 mL 14 % boron trifluoride in methanol with 0.3 mL hexane.…”

“…However, this process still requires between one and three hours to complete with boron trifluoride (BF 3 ) [11] and sulfuric acid (H 2 SO 4 ) [12], respectively. Furthermore, rapid collection and subsequent pressures placed on storage capabilities, particularly in the absence of −80 °C storage [13], increases the importance of employing more rapid analytical techniques to ease the storage burden.…”

Elucidating the roles of stearoyl-CoA desaturase 1 in adipocyte fatty acid metabolism and cellular function

“…The GC settings were as previously described [221]. Peaks were identified by retention times through comparison to an external mixed standard sample (GLC-462, Nu…”