Effect of long-term consumption of a diet with a high sodium chloride content on microRNA expression in blood serum and urine of Cynomolgus Macaques

Abstract

INTRODUCTION. A high intake of sodium chloride from food is associated with damage not only to the cardiovascular system but also to the kidneys. The mechanisms of the negative effects of high-salt diets on the kidneys have not been established. One of the important links in this process can be microRNAs, which can modulate gene expression at the post-transcriptional level. It is also not known whether soy proteins can counter the kidney remodeling associated with increased salt intake.THE AIM. To estimate the expression levels of miRNA-133 and 203 in blood serum and urine and miRNA-21 in the urine of cynomolgus macaques received diets for a long time with various table salt contents, including and not including soy proteins.MATERIALS AND METHODS. Three groups (6 individuals in each) of male cynomolgus macaques at the age of 6–8 years were studied. The first group (control) received a standard diet, the second – a diet with a high content of table salt (8 g NaCl / kg feed), the third – a diet with high salt content in combination with SUPRO 760 soy protein (200 g protein/kg feed). Blood pressure was measured in animals 12 months later. In monkey urine, the relative expression levels of miRNA-21, miRNA-133, and miRNA-203 were determined, in blood serum – the expression levels of miRNA-133 and miRNA-203.RESULTS. During the follow-up period in the control group, there were no significant changes in the studied parameters. In the groups that received high-salt diets throughout the year, blood pressure also did not change significantly. There was no change in the level of expression of miRNA-133 in the blood serum of monkeys fed a high-salt diet and a standard protein diet. However, in macaques fed a diet high in salt in combination with soy protein, the serum expression of this miRNA was significantly reduced. The expression of miRNA-203 in blood serum did not change significantly. In the control group, there were no changes in the expression of miRNA-21 in urine. In the other two samples, this parameter increased in comparison with the initial values. Both high-salt diets resulted in a significant increase in the relative level of miRNA-133 expression in urine compared to basal values. However, the increase in this indicator 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. Expression of miRNA-203 in urine was significantly increased only in the group with a high content of table salt without added soy protein.CONCLUSIONS. It is possible that the effects of high-salt diets on the kidney may be mediated by epigenomic mechanisms and partially modulated by the inclusion of isolated soy proteins in the diet.