01.09 The Circulating Plasma miRNA Profile In Response To Vascular Injury

T. Yoo1, M. Haurani1, C. Rink1  1Ohio State University,Vascular Surgery,Columbus, OH, USA

Introduction: miRNA are short non-coding nucleotides that post-transcriptionally regulate messenger RNA. Recently, they have been discovered to be stable and amplifiable components of circulating plasma that are implicated in inflammation and remodeling. Here, we seek to identify novel circulating miRNA targets that are differentially expressed in response to vascular injury. 

Methods:  Rats underwent no surgery, sham left external carotid ligation, or left carotid balloon injury. Plasma samples were obtained at day 3 and day 14 after surgery. Carotid arteries were collected, sectioned and H&E stained to measure intimal hyperplasia. High resolution in vivo ultrasound was performed and analyzed to assess wall variation and intimal thickness in response to balloon angioplasty. Plasma miRNA was purified, then quantified via nCounter. Differentially expressed targets were validated with qPCR. Target Scan and Ingenuity Pathway Analysis were used to predict possible in silico targets of validated miRNA.

Results: Of the 449 genes on array, 35 were detected over background in cell free plasma samples with no indication of cellular contamination by qPCR or cell housekeeping markers. At day 3 after balloon injury there was no significant change in the miRNA profile. However, at post-injury day 14, miRNA-16 and miRNA-223 which are known to regulate proliferative and inflammatory pathways, significantly decreased compared to sham and non-operated animals (miRNA-16, Relative Expression 0.16, p = 0.001, miRNA-223 Relative Expression 0.08, p< 0.001) This corresponded to an increase in intimal thickness as detected by high-resolution, non-invasive in vivo ultrasonography and histology.

Conclusion: We have identified key circulating plasma miRNA transcriptome components that correlate to the formation of intimal hyperplasia. Identification of these targets may further elucidate miRNA regulation of vascular inflammation as well as serve as predictive biomarkers of re-stenosis following balloon injury.