Stability of targeted metabolite profiles of urine samples under different storage conditions

Abstract

IntroductionFew studies have investigated the influence of storage conditions on urine samples and none of them used targeted mass spectrometry (MS).ObjectivesWe investigated the stability of metabolite profiles in urine samples under different storage conditions using targeted metabolomics.MethodsPooled, fasting urine samples were collected and stored at −80 °C (biobank standard), −20 °C (freezer), 4 °C (fridge), ~9 °C (cool pack), and ~20 °C (room temperature) for 0, 2, 8 and 24 h. Metabolite concentrations were quantified with MS using the AbsoluteIDQ™ p150 assay. We used the Welch-Satterthwaite-test to compare the concentrations of each metabolite. Mixed effects linear regression was used to assess the influence of the interaction of storage time and temperature.ResultsThe concentrations of 63 investigated metabolites were stable at −20 and 4 °C for up to 24 h when compared to samples immediately stored at −80 °C. When stored at ~9 °C for 24 h, few amino acids (Arg, Val and Leu/Ile) significantly decreased by 40% in concentration (P < 7.9E−04); for an additional three metabolites (Ser, Met, Hexose H1) when stored at ~20 °C reduced up to 60% in concentrations. The concentrations of four more metabolites (Glu, Phe, Pro, and Thr) were found to be significantly influenced when considering the interaction between exposure time and temperature.ConclusionOur findings indicate that 78% of quantified metabolites were stable for all examined storage conditions. Particularly, some amino acid concentrations were sensitive to changes after prolonged storage at room temperature. Shipping or storing urine samples on cool packs or at room temperature for more than 8 h and multiple numbers of freeze and thaw cycles should be avoided.Electronic supplementary materialThe online version of this article (doi:10.1007/s11306-016-1137-z) contains supplementary material, which is available to authorized users.

Night Shift Work Affects Urine Metabolite Profiles of Nurses with Early Chronotype

“…Furthermore, medium- and long-chain acylcarnitines produced in the kidney via fatty acid oxidation are directly secreted to the urine [ 31 ]. Inside mitochondria, the fatty acid oxidation is influenced by the NAD+ levels [ 8 , 12 , 15 ]. The nicotinamide phosphoribosyl transferase (NAMPT), a rate limiting enzyme of NAD+ synthesis, is regulated by the CLOCK/BMAL1 (Circadian Locomoter Output Cycles Kaput/Brain and Muscle Aryl hydrocarbon receptor nuclear translocator-Like 1) protein complex [ 32 , 33 , 34 ].…”

“…Each urine sample was measured with the Absolute IDQ TM p150 Kit (BIOCRATES Life Sciences AG, Innsbruck, Austria) using FIA-ESI-MS/MS (flow injection-electrospray ionisation-triple quadrupole mass spectrometry) [ 15 , 45 ]. In 10 µL urine, 162 metabolites were quantified ( Table S1 ).…”

“…In 10 µL urine, 162 metabolites were quantified ( Table S1 ). We applied the same quality control (QC) criteria as in our previous study [ 15 ]. Overall, 2990 urine samples were measured in two batches.…”

“…However, no real-life study investigating the impact of night shift work on the urine metabolic profile of participants with early, intermediate and late chronotype has been reported. Major advantages of urine bio samples are their non–invasive sampling, moreover, urine samples are well studied with respect to age, obesity and storage conditions [ 14 , 15 , 16 , 17 ]. However, as urine samples are susceptible to a variety of factors such as water intake, it was suggested to either use alternative methods besides creatinine- or osmolality-normalizations, or to apply more than one normalization method [ 18 , 19 , 20 ].…”

Urine Tests for Diagnosis of Infectious Diseases and Antibiotic-Resistant Pathogens

“…Generally, the length of preservation capacity ranges from 24 to 72 hours. Metabolites which can be significantly influenced by the interaction of exposure time and temperature include arginine, glutamine, methionine, phenylalanine, and others, while metabolites which can be significantly influenced by freeze and thaw cycles are the C3 family and histones H1 [44].…”