[Urinary miRNA expression in cynomolgus macaques (Macaca fascicularis) fed high salt rations]

High food intake of sodium chloride is associated with damage not only the cardiovascular system, but also the kidneys. The mechanisms of the potential negative effects of high-salt diets on the kidneys have not been established. The aim of the study was to trace the changes in relative expression of miRNA-21, 203 and 133 in urine of cynomolgus macaques (Macaca fascicularis) fed high-salt diet with and without isolated soy proteins. Material and methods. The object of the study was 18 male cynomolgus macaques (Macaca fascicularis) aged 6-8 years with a body weight of 5.1-9.7 kg. The animals were divided in 3 groups (6 individuals each). The animals of the first (control) group received a standard diet (2 g NaCl/kg feed). The animals of the second group were fed high-salt diet (8 g NaCl/kg feed), of the third - high-salt diet combined with SUPRO 760 isolated soy protein (200 g/kg feed; instead of milk and egg proteins, corn gluten). Access to water was free. The follow-up period in this study was 4 months. In animals blood pressure (BP) and relative level of microRNA (miRNA) expression in urine were measured. Results and discussion. Keeping monkeys on the studied diets for 4 months did not lead to significant changes in systolic or diastolic BP compared with the initial level. In the control group, there were no distinct changes in the expression of miRNA-21 in urine during observation. In the other two groups, there was a significant increase (approximately equally) of this parameter in comparison with the initial values. Both high-salt diets resulted in a significant increase in the relative level of expression of miRNA-133 and miRNA-203 in urine compared to basal values. However, the increase in these parameters in the group of animals fed a high-salt diet in combination with soy isolate was significantly less than in monkeys fed only a high-salt diet. Conclusion. Possible, potentially negative effects of high-salt diets on kidney may be mediated by epigenomic mechanisms and partially modulated by the inclusion of isolated soy proteins in the diet.