Atherosclerotic Plaque Fissuration and Clinical Outcomes in Pre-Diabetics vs. Normoglycemics Patients Affected by Asymptomatic Significant Carotid Artery Stenosis at 2 Years of Follow-Up: Role of MIcRoRNAs Modulation. The ATIMIR Study

BACKGROUND AND PURPOSE—Atherosclerotic plaque instability and rupture in patients with asymptomatic carotid artery stenosis (ACAS) is a leading cause of major adverse cardiac events (MACE). This could be mainly evidenced in patients with pre-diabetes. Indeed, the altered glucose homeostasis and insulin resistance could cause over-inflammation of atherosclerotic plaque, favoring its conversion to unstable phenotype with rupture and MACE. Notably, the metformin therapy reducing the metabolic distress and the inflammatory burden, could lead to reduction of MACE in ACAS patients with pre-diabetes. In this setting, microRNAs (miRs) could be used as molecular biomarkers of atherosclerosis progression, plaque rupture and worse prognosis in normoglycemics (NG) vs. pre-diabetics metformin users (PDMU) vs. pre-diabetics non metformin users (PDNMU). However, the aim of our study was to investigate a wide miRNA panel in peripheral blood exosomes from patients with ACAS divided in NG vs. PDMU vs. PDNMU, and to associate the circulating miRNA expression profiles with MACE at 2 years of follow-up after endarterectomy. METHODS—The study included 234 patients with ACAS divided in NG (n 125), PDNMU (n 73) and PDMU (n 36). The miRs’ expression profiles of circulating exosomes were determined at baseline and at 2 years of follow-up by Affymetrix microarrays from plasma samples of the patients from any study cohort. Then we collected and analyzed MACE at 2 years of follow-up in NG vs. PDMU vs. PDNMU. RESULTS—prediabetics vs. NG had over-inflammation (p<0.05) and over expressed miR 24 and miR 27 at baseline. At 2 years of follow-up PDNMU vs. NG, PDMU vs. NG and PDNMU vs. PDMU over-expressed inflammatory markers and miR 24, miR 27, miR 100, miR 126 and miR 133 (p<0.05). Finally, at follow-up end we observed a significant difference about MACE comparing PDNMU vs. NG (n 27 (36.9%) vs. n 8 (6.4%); p<0.05), PDNMU vs. PDMU (n 27 (36.9%) vs. n 6 (16.6%); p <0.05), and PDMU vs. NG (n 6 (16.6%) vs. n 8 (6.4%); p<0.05). Admission glucose values (HR 1.020, CI 95% [1.001-1.038], p 0.029), atheromatous carotid plaque (HR 5.373, CI 95% [1.251-11.079], p 0.024), and miR 24 (HR 3.842, CI 95% [1.768-19.222], p 0.011) predicted MACE at 2 years of follow-up. CONCLUSIONS—Specific circulating miRs could be over-expressed in pre-diabetics and specifically in PDNMU vs. PDMU after endarterectomy. MiR24, hyperglycemia and atheromatous plaque could predict MACE at 2 years of follow-up.