The Effect of Tropical Temperatures on the Quality of RNA Extracted from Stabilized Whole-Blood Samples

Abstract

Whole-blood-derived transcriptional profiling is widely used in biomarker discovery, immunological research, and therapeutic development. Traditional molecular and high-throughput transcriptomic platforms, including molecular assays with quantitative PCR (qPCR) and RNA-sequencing (RNA-seq), are dependent upon high-quality and intact RNA. However, collecting high-quality RNA from field studies in remote tropical locations can be challenging due to resource restrictions and logistics of post-collection processing. The current study tested the relative performance of the two most widely used whole-blood RNA collection systems, PAXgene® and Tempus™, in optimal laboratory conditions as well as suboptimal conditions in tropical field sites, including the effects of extended storage times and high storage temperatures. We found that Tempus™ tubes maintained a slightly higher RNA quantity and integrity relative to PAXgene® tubes at suboptimal tropical conditions. Both PAXgene® and Tempus™ tubes gave similar RNA purity (A260/A280). Additionally, Tempus™ tubes preferentially maintained the stability of mRNA transcripts for two reference genes tested, Succinate dehydrogenase complex, subunit A (SDHA) and TATA-box-binding protein (TBP), even when RNA quality decreased with storage length and temperature. Both tube types preserved the rRNA transcript 18S ribosomal RNA (18S) equally. Our results suggest that Tempus™ blood RNA collection tubes are preferable to PAXgene® for whole-blood collection in suboptimal tropical conditions for RNA-based studies in resource-limited settings.

Effects of storage temperature, storage time, and hemolysis on the RNA quality of blood specimens: A systematic quantitative assessment

“…Previous research has shown that pre-analytical variables can affect analytical RNA procedures, such as RT-qPCR [ 31 ]. In this research, the gene expression of 18S remained relatively stable, which is supported by a previous study [ 32 ]. The expression of ATCB significantly decreased upon storage at room temperature for 24 h or freeze-thaw.…”

“…They found that the purity of blood RNA did not significantly change for different preservation durations (from 1 h to 7 days), and that the integrity significantly decreased after rabbit blood had been stored at 4 °C for over 3 days. Moreover, expression of PCNA of whole blood RNA is significantly decreased over 24 h. The results of Sarathkumara et al [ 17 ] showed that RIN values declined over time and with temperature irrespective of the whole-blood collection tube.…”