Abstract 540: Impaired Microvascular Angiogenesis And Altered Tissue MicroRNA In Patients With Peripheral Artery Disease

Abstract

Microvascular dysfunction contributes to adverse clinical outcomes in patients with peripheral artery disease (PAD). Compromised angiogenesis is an important mechanism of limb ischemia that may be a treatment target but is challenging to assess in patients. Selected circulating microRNA (miRNAs) have been implicated in the pathogenesis of PAD. Thus, we sought to characterize angiogenesis potential and identify altered miRNA in patients with PAD. We collected adipose tissue from ischemic limbs of patients with PAD (n=15, age=64±11, 33% women, 66% T2DM, 61% current smoking) at the time of revascularization surgery. Control adipose tissue was procured patients without PAD undergoing joint replacement surgery (n=6, age=58±6, 50% women, 17% T2DM, 33% current smoking). Using matrigel sprouting assay, we observed a significantly lower angiogenesis response over 8 days in adipose tissue samples from PAD patients compared to controls (p=0.008). We performed miRNA profiling using NextSeq (Illumina Inc.) sequencer. miRNA NGS libraries were prepared using QIAseq miRNA Library Kit. Quality controlled NGS libraries were sequenced according to the manufacturer protocol. Our results demonstrated 40 upregulated and 11 downregulated miRNAs (FDR q<0.01, log2 fold change>2). Using bioinformatics approaches to prioritize differentially expressed miRNA predicted to impact pathways relevant to cardiovascular disease, we identified miR205-5p and miR182-5p as top candidate. There were higher levels of miR205-5p (4.8-fold, FDRq=1.5e-10) and miR182-5p (4.1-fold, FDRq=5.4e-16) in adipose tissue from PAD patients compared to controls. We confirmed the differentially expressed levels using qPCR in selected samples. Ingenuity pathway analysis indicates that miR205-5p inhibits VEGF-A, a key regulator of angiogenesis. We observed a trend toward an association of miR205-5p (r=-0.58, p=0.1) and miR182-5p (r=-0.67, p=0.06) and lower angiogenesis response. Taken together our findings demonstrate impaired microvascular angiogenesis response in patients with PAD along with upregulation of selected miRNA predicted to impair angiogenesis pathways. Further work is needed to confirm a functional role of miRNA in the impaired angiogenesis in patients with PAD.