Long-term storage of blood RNA collected in RNA stabilizing Tempus tubes in a large biobank – evaluation of RNA quality and stability

Abstract

BackgroundEstablishing methods for secure long term storage of RNA is critical to realizing the promise of biobanks in biomedical research. Here, we describe the results of yearly analyses of the same set of umbilical cord and adult whole blood RNA collected in Tempus Blood RNA tubes and stored at -80°C, over a period of up to six years. We systematically investigated the effects of long-term storage of samples (75 Tempus tubes form three adult donors and 30 Tempus tubes from three cord blood donors) on the RNA quality and transcript stability of six selected genes (CDKN1A, FOS, IL1B, IL8, MYC and TP53). This is the first systematic study of both cord and adult blood samples stored for many years.FindingsThe RNA purity and integrity, expressed as RIN-values, were stable up to six years of storage, and there were no storage-related deleterious effects on RNA purity. There were limited intra- and inter-individual variations in RNA yields; however, no consistent trend of decreasing RNA yield was observed with the duration of storage. Some long-term storage effects were found on the relative transcript levels of the six genes when compared to the year 0 samples. However, these changes were within ± 2–fold for both types of blood samples, except for two genes. Our results show that storage of these samples for up to six years did not have significant effects on the RNA quality and transcript stability of the six genes.ConclusionsBlood RNA is stable in Tempus tubes stored at -80°C over a period of six years. Intact and good-quality RNA suitable for transcript profiling analyses in epidemiological studies was obtained from blood samples stored in Tempus tubes. This suggests that blood samples collected in large biobanks–such as the Mother and Child (MoBa) Cohort at Norwegian Institute of Public Health (NIPH) and frozen in suitable collection tubes for total RNA stabilization, can be used for quantitative studies after at least six years of storage.Electronic supplementary materialThe online version of this article (doi:10.1186/1756-0500-7-633) contains supplementary material, which is available to authorized users.

MiRNA profiles in blood plasma from mother-child duos in human biobanks and the implication of sample quality: Circulating miRNAs as potential early markers of child health

“…Participants were recruited from all over Norway from 1999 to 2008, and the cohort now includes more than 114.500 children, 95.200 mothers, and 75.200 fathers [12]. Biological material in the form of whole blood and plasma has been collected from the mother, the father, and the child (umbilical cord blood) and stored in the biobank, together with extracted DNA, for future use [16,20,21].…”

“…However, reliable quantification of mRNA and miRNA levels requires high-quality RNA, and compromised RNA integrity has been shown to influence such quantification [13][14][15]. Previously, we reported that intact and high-quality RNA suitable for mRNA profiling analyses was obtained from blood samples collected in Tempus tubes and stored at -80˚C over a period of up to six years [16]. Different RNA isolation methods have also been compared for quality and yield when isolating from blood samples collected in Tempus tubes and stored in biobanks [17].…”

The biobank of the Norwegian Mother and Child Cohort Study – present status

“…The procedures and testing to establish a practical protocol for sampling, handling, transportation and storage of blood RNA is described elsewhere (8). Recently, also the effects of long-term storage of blood RNA collected in RNA stabilizing Tempus tubes was reported (9).…”

RNA stabilized blood tubes to measure haemoglobin concentration

“…It was also demonstrated that the same strategy was applicable for the detection of erythropoietin stimulating agents in micro‐doses . RNA stabilized blood tubes such as Tempus™ blood RNA tubes are mainly used for multi‐site clinical studies in order to facilitate the transport and storage of samples . Indeed, Tempus™ tubes are stable at room temperature for up to five days, unlike EDTA tubes that have to be kept at 4°C and analysed within 48 hours after collection.…”

“…[2] RNA stabilized blood tubes such as Tempus ™ blood RNA tubes are mainly used for multi-site clinical studies in order to facilitate the transport and storage of samples. [3,4] Indeed, Tempus ™ tubes are stable at room temperature for up to five days, unlike EDTA tubes that have to be kept at 4°C and analysed within 48 hours after collection. Theoretically, reticulocyte messenger RNA (mRNA) biomarkers could complement the already existing athlete biological passport (ABP) variables and provide additional evidence for blood manipulation.…”