Abstract
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, metformin therapy reducing the metabolic distress and the inflammatory burden could reduce MACE in ACAS patients with pre-diabetes. In this setting, the microRNAs (miRs) could be used as molecular biomarkers of atherosclerosis progression, plaque rupture, and worse prognosis in normoglycemics (NG) versus pre-diabetics metformin users (PDMU) versus pre-diabetics non-metformin users (PDNMU). However, our study aimed to investigate a wide miRNA panel in peripheral blood exosomes from patients with ACAS divided in NG versus PDMU versus PDNMU, and to associate the circulating miRNA expression profiles with MACE at 2 years of follow-up after endarterectomy. The study included 234 patients with ACAS divided into 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 the patients' plasma samples from any study cohort. Then we collected and analyzed MACE at 2 years of follow-up in NG versus PDMU versus PDNMU. Prediabetics versus NG had over-inflammation (p < 0.05) and over expressed miR-24 and miR-27 at baseline. At 2 years of follow-up, PDNMU versus NG, PDMU versus NG, and PDNMU versus PDMU over-expressed inflammatory markers and miR-24, miR-27, miR-100, miR-126, and miR-133 (p < 0.05). Finally, at the end of follow-up, we observed a significant difference about MACE comparing PDNMU versus NG (n = 27 (36.9%) versus n = 8 (6.4%); p < 0.05), PDNMU versus PDMU (n = 27 (36.9%) versus n = 6 (16.6%); p < 0.05); and PDMU versus NG (n = 6 (16.6%) versus n = 8 (6.4%); p < 0.05). Admission glucose values (HR (hazard ratio) 1.020, CI (confidence of interval) 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. Specific circulating miRs could be over-expressed in pre-diabetics and specifically in PDNMU versus PDMU after endarterectomy. MiR24, hyperglycemia, and atheromatous plaque could predict MACE at 2 years of follow-up.