IntroductionThis study aimed to evaluate the TRE-induced changes in the serum expression levels of miRNAs associated with lipids metabolism and autophagy process in MI patients to assess the potential protective effects of TRE in these patients.Material and methodsThis post hoc investigation was performed on serum samples obtained from a pilot randomized, double blind, placebo-controlled clinical trial that recruited 14 men (aged 18-80) who had MI and systemic inflammation. The patients were randomized in a 2:1 ratio to either TRE (15 g/week, intravenous (IV) ad-ministration) (N=10) or placebo groups (equal volume of saline 0.9 %) (N=4) for a period of 12 weeks. To measure the relative serum expression levels of miRNA-155, miRNA-221, and miRNA-33, the SYBR Green qPCR method was used.ResultsmiRNA-155 showed significantly higher serum expression levels in the TRE group (2.772±0.73; P=0.009) when compared to the placebo group. Also, significant reductions in miRNA-155 (0.171±0.03; P=0.016), miRNA-221 (0.116±0.07; P=0.013), and miRNA-33a (0.076±0.07; P=0.025) were observed in the placebo group at the end of the study. Nevertheless, the reduction (normalized to the baseline) of the serum expres-sion levels of miRNA-221 (FC:0.87±0.20 vs FC:0.18±0.08; P=0.009) and miRNA-33a (FC:0.73±0.22 vs FC:0.13±0.08; P=0.025) were significantly less in TRE group than in the placebo group.ConclusionsIV TRE administration did not reduce the expression of miRNA-221 and miRNA33a as much as placebo. Keeping a steady state of the serum expression levels of these miRNAs associated with lipoproteins metabolism and autophagy in the TRE group might have protective effects in patients with MI.