Asbestos Diseases Research Institute, University of Sydney , Sydney, NSW , Australia.
Front Genet. 2013 May 24;4:94. doi: 10.3389/fgene.2013.00094. eCollection 2013.
Cell-free microRNAs in plasma and serum have become a promising source of biomarkers for various diseases. Despite rapid progress in this field, there remains a lack of consensus regarding optimal quantification methods, reference genes, and quality control of samples. Recent studies have shown that hemolysis occurring during blood collection has substantial impact on the microRNA content in plasma/serum. To date, the impact of hemolysis has only been investigated for a limited number of microRNAs, mainly the red blood cell (RBC)-enriched miRs-16 and -451. In contrast, the effect of hemolysis on other microRNAs - in particular those proposed as biomarkers - has not been addressed. In this study we profiled the microRNA content of hemolyzed and non-hemolyzed plasma as well as RBCs to obtain a profile of microRNAs in the circulation affected or unaffected by hemolysis. Profiling by TaqMan Array Microfluidic Cards was used to compare three pairs of hemolyzed and non-hemolyzed plasma (with varying degrees of hemolysis) and one RBC sample. A total of 136 microRNAs were detectable in at least two of the samples, and of those 15 were at least twofold elevated in all three hemolyzed samples. This number increased to 88 microRNAs for the sample with the highest level of hemolysis, with all of these also detected in the RBC profile. Thus these microRNAs represent a large proportion of detectable microRNAs and those most likely to be affected by hemolysis. Several of the hemolysis-susceptible microRNAs (e.g., miRs-21, -106a, -92a, -17, -16) have also been previously proposed as plasma/serum biomarkers of disease, highlighting the importance of rigorous quality control of plasma/serum samples used for measurement of circulating microRNAs. As low-level hemolysis is a frequent occurrence during plasma/serum collection it is critical that this is taken into account in the measurement of any candidate circulating microRNA.
血浆和血清中的无细胞 microRNAs 已成为各种疾病生物标志物的有前途的来源。尽管该领域取得了快速进展，但在最佳定量方法、参考基因和样本质量控制方面仍缺乏共识。最近的研究表明，在采血过程中发生的溶血对血浆/血清中的 microRNA 含量有重大影响。迄今为止，仅对少数 microRNAs（主要是富含红细胞的 miR-16 和 -451）进行了溶血影响的研究。相比之下，溶血对其他 microRNAs 的影响——特别是那些被提议作为生物标志物的 microRNAs——尚未得到解决。在这项研究中，我们对溶血和非溶血血浆以及 RBC 中的 microRNA 含量进行了分析，以获得受或不受溶血影响的循环 microRNA 图谱。通过 TaqMan Array Microfluidic Cards 进行分析，比较了三对溶血和非溶血血浆（溶血程度不同）和一个 RBC 样本。至少有两个样本中可检测到 136 个 microRNAs，其中 15 个在所有三个溶血样本中至少增加了两倍。对于溶血程度最高的样本，这个数字增加到 88 个 microRNAs，所有这些 microRNAs也都在 RBC 图谱中检测到。因此，这些 microRNAs 代表了可检测 microRNAs 的很大一部分，并且最有可能受到溶血的影响。一些易受溶血影响的 microRNAs（例如，miR-21、-106a、-92a、-17、-16）也被先前提议为血浆/血清疾病生物标志物，这突出了严格控制用于测量循环 microRNA 的血浆/血清样本质量的重要性。由于在采集血浆/血清过程中经常发生低水平的溶血，因此在测量任何候选循环 microRNA 时都必须考虑这一点。
