miRNAs as a tool for the diagnosis of suspected Brugada Syndrome

Abstract Background/Introduction Brugada syndrome (BrS) is a life-threatening arrhythmogenic disease that can lead to sudden unexplained death/cardiac arrest in otherwise healthy individuals. ECG represents the gold standard for the diagnosis. In 30% of cases, however, the syndrome is diagnosed only after a provocative test with sodium channel blockers [1]. Among the different approaches to support diagnosis, circulating biomarkers such as miRNAs may represent a tool that can provide a biological signature of the syndrome in patients with suspected BrS. Purpose Within the BrS and Artificial Intelligence Applications to Diagnosis system study, we collected and analyzed blood samples from patients with suspected BrS undergoing provocative tests aiming to assess whether miRNAs may be potential markers to identify the syndrome. Methods Patients undergoing provocative tests with sodium channel blockers (i.e., ajmaline, flecainide) were classified as positive (15 patients) and negative (13 patients) based on the test results. Blood samples were obtained when a Type-1 ECG pattern developed (for positive) or at the end of the provocative test without any electrographic changes (negative). miRNAs were extracted from circulating exosomes, obtained by blood samples, using a dedicated and innovative assay (exoRNeasy mini/midi kit, QIAGEN). They were quantified and quality tested by Agilent 2100 Bioanalyzer RNA assay; miRNA-seq was carried out with NovaSeq 6000 (Illumina, San Diego, CA). Data were analyzed through web-based platforms for network visual analytics (mirNET 2.0). Results The presence of 8 small RNAs up-regulated was reported in the positive group (hsa-miR-155-5p ,hsa-miR-10a-5p, hsa-miR-29a-3p, hsa-miR-142-5p, hsa-miR-30a-5p, hsa-miR-126-5p, hsa-miR-95-3p, hsa-miR-126-3p), with a log fold-change between 6.4 (as for hsa-miR-95-3p) and up to 615.0 (as for hsa-miR-126-3p) (Table 1). The network analysis results (Figure 1) on this group of miRNAs showed their involvement, among the others, in response to cytokine and muscle development (in terms of function analysis) and Ca2+pathway modulation (in terms of pathway analysis). Conclusion(s) In this work, a miRNA analysis of patients undergoing provocative tests for Type-1 BrS diagnosis was performed. Our results show a set of potential miRNAs that could be used to identify Type 1 BrS patients in whom the typical ECG pattern is basally lacking. Although further experiments and validation on a larger number of samples are necessary, our results could identify these miRNAs as potential early markers in patients with a suspected Type-1 BrS diagnosis.Upregulated miRNAs in BrS patientsMiRNA network analysis