Effects of Multi-species Synbiotic Supplementation on Circulating miR-27a, miR-33a Levels, and Lipid Parameters in Adult Men with Dyslipidemia; A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.

MicroRNAs (miRNAs) have emerged as important regulators of lipid metabolism. Recent studies have suggested synbiotics may modulate miRNA expression and lipid metabolism. This study aimed to investigate the effects of synbiotic supplementation on circulating miR-27a, miR-33a, and lipid parameters in patients with dyslipidemia. Fifty-six eligible participants were randomly allocated to receive either synbiotic or placebo sachets twice a day for 12 weeks. Each synbiotic sachet contained 3×1010 CFU six species of probiotic microorganisms and 5 grams of inulin and fructooligosaccharide (FOS) as prebiotics. Serum miR-27a and miR-33a expression levels, serum lipids, and apolipoproteins, the fecal concentration of short-chain fatty acids (SCFAs), and Firmicutes and Bacteroidetes phyla were assessed before and after the study. Real-time PCR was used to determine the relative expression levels of miRNAs. The results showed synbiotic supplementation significantly downregulated the expression levels of miR-27a and miR-33a compared to the placebo group ( p = 0.008 and p = 0.001, respectively). Furthermore, the intervention group exhibited significant improvements in serum high-density lipoprotein (HDL-C), small dense low-density lipoprotein (sdLDL-C), apoA-I, and apoB-100 ( p = 0.008, p = 0.006, p = 0.003, p = 0.001, respectively). The results showed a significant negative correlation between miR-33a expression levels with HDL-C, butyrate, propionate, and a significant positive correlation with total cholesterol (TC), low-density lipoprotein (LDL-C), and sdLDL-C in the intervention group. Fecal bacteria and SCFAs were significantly increased in the intervention group. This study provides evidence that synbiotic supplementation can modulate miR-27a and miR-33a expression and improve lipid metabolism in patients with dyslipidemia.