Clinical blood sampling for oxylipin analysis – effect of storage and pneumatic tube transport of blood on free and total oxylipin profile in human plasma and serum

Abstract

Choice of blood specimen and suitable pre-analytical sample handling is crucial for quantitative oxylipin analysis in clinical studies.

Plasma oxylipin levels associated with preterm birth in preterm labor✰

“…The corresponding numbers for 8-HETE were 7% delivery within 48 hours in the two lowest quartiles and 28% in the two highest quartiles (adjusted OR 5.01 (1.13-22.14); p=0.034) (Table 3). Furthermore, since the sampling protocol and pneumatic tube transport have been reported to influence a subset of oxylipins [26], we investigated the potential impact of these factors on our data set. In the univariate logistic regression analysis there was a tendency to find a statistically significant association between not using pneumatic tube transport and delivery before 34 weeks (p=0.053); however, in the multivariate analysis an association was not verified (p=0.127) (Table 2).…”

“…Here, only oxylipins with at least 40% of values above the limit of detection (LOD) were taken into consideration, and values below LOD were substituted with LOD/√2 [25]. Multivariate logistic quantile regression models were adjusted for usage of pneumatic tube systems for sample transport, as this may affect oxylipin levels [26]. Adjacent quartiles of statistically significant variables were combined if the actual frequencies were similar or opposite to the significant trend.…”

Fatty acid and oxylipin concentration differ markedly between different fetal bovine serums: A cautionary note

“…As expected, the highest concentrations were found for the 12-lipoxygenase (LOX) products 12-hydroxy eicosatetraenoic acid (HETE), 12hydroxy eicosapentaenoic acid (HEPE), and 14-hydroxy docosahexaenoic acid (HDHA). During coagulation, platelets and subsequent 12-LOX are activated, leading to massively increased concentrations of these oxylipins in serum (Rund et al, 2020). For 12-LOX products, the difference in the concentrations between the serums is most pronounced, which might be explained by inconsistent serum generation procedures of the different companies.…”

Metabolite Ratios as Quality Indicators for Pre-Analytical Variation in Serum and EDTA Plasma

“…These enzymes are strongly activated in platelets during aggregation and coagulation [ 40 , 41 ], induced by clot activators in serum samples immediately after blood collection. The previously observed high concentrations of eicosanoids in serum [ 42 ] compared to EDTA plasma results from the increased release and metabolism of PUFAs. For example, Dorow and colleagues found tremendously elevated levels of 11-, 12-, 15-HETE, 12-HHT, and TxB 2 of up to 18,803% relative to EDTA plasma [ 43 ].…”