microRNA expression profiling of patients affected by first acute myocardial infarction (FAMI)

Background: Myocardial infarction (MI) is the single most critical event in coronary disease. Platelets partecipate in processes that precipitate acute MI, lack nuclear DNA but retain megakaryocyte mRNAs, thus their transcriptome could provide information preceding the coronary event. Our aim was to obtain a gene expression atlas of platelets from patients with their very first acute MI (FAMI) in order to identify potential markers of precipitating factors. Methods and results: Platelets from seventeen FAMI patients and matched controls were collected and RNA and protein were purified. Expression profiles were obtained with genome-wide microarrays. Platelet-specific proteomic analysis was also performed with fluorescent DIGE separation in the same samples. Strong transcriptional down-regulation was observed in patient platelets, whereas more balanced numbers of up and down-represented proteins were found by proteomic analysis. Conclusions: Platelet transcriptome revealed quantitative differences between FAMI patients and controls. The functional analysis deregulated mRNAs and the integration with proteomic data in platelets may suggest pre-activation of platelets and/or megakaryocytes in FAMI patients before the acute event. miRNA expression profiling was analysed in platelets from 4 patients with their very first acute MI (FAMI) and in 3 controls. We performed miRNA expression profiling from 200 ng of total RNA and following the miRNA Microarray System protocol v. 1.5 (Agilent Technologies). The level of each miRNA was represented as Ln.