Comparison of miRNA expression profile between arterial plasma and venous plasma

Circulating microRNAs (miRNAs) presented in venous plasma have recently been demonstrated as powerful biomarkers for the diagnosis and prognostic prediction of complex diseases like cancer. Nevertheless, those presented in arterial plasma have been ignored based on the assumption that the miRNA profiles in arterial and venous plasma would be identical. Here, we disputed this intuitive assumption by comparing arterial and venous plasma miRNA expression profiles from male rats using microarray technique. Though the microRNA profiles were largely similar, a considerable number of miRNAs showed significant differential expression, including 10 arterial highly expressed miRNAs and 14 venous highly expressed miRNAs. The differentially expressed miRNAs were validated by qRT-PCR. We performed computational analysis of the function enrichment and disease association of these miRNAs and their targets. Our analysis also suggested significant correlations between plasma miRNA expression and tissue miRNA expression. Four arterial highly expressed miRNAs showed enriched expression in specific tissues and thus could serve as novel biomarker candidates. Three healthy male rats were prepared. For each rat, one arterial plasma sample and one venous plasma sample were extracted. MiRNA expression profiles in three matched pairs of arterial/venous plasma samples were measured by using microarray.