Effects of long-term high dietary sodium chloride intake on the cardiovascular system of cynomolgus macaques (<i>Macaca fascicularis</i>)

Abstract

INTRODUCTION . High dietary sodium chloride intake has traditionally been considered an important factor in cardiovascular risk and an increase in blood pressure (BP). However, much remains unclear about the relationship between dietary sodium and cardiovascular health. In particular, it was shown that in rats a high content of salt in the diet can lead to miocardial remodeling/damage without increasing BP. It is possible whether this phenomenon in primates remains unknown. The AIM of the study was to trace the dynamics of BP and some echocardiographic (EchoCG) parameters in cynomolgus macaques ( Macaca fascicularis ), which have been on a high sodium chloride diet for a long time. MATERIAL AND METHODS . 12 male cynomolgus macaques 6-8 years with a body weight of 5,15-9,7 kg were studied. The animals were divided into two groups (six individuals each). The first (control) received a standard diet, the second – a diet high in sodium chloride (8 g NaCl/kg feed). After four and fourteen months, in the animals were measured blood pressure and conducted echocardiographic examination (EchoCG). RESULTS . During the follow-up period in the control group, no significant changes in the studied parameters were recorded. Increased salt intake at four months resulted in a significant decrease in left ventricular end-systolic dimension and an increase in ejection fraction values. After fourteen months, both of these indices returned, practically, to the initial level, but there was a significant increase in the thickness of the posterior wall of the left ventricle in systole and a decrease in systolic excursion of the tricuspid valve annulus compared with the basal data. BP in the salt group also did not change significantly. CONCLUSION . Cynomolgus macaques are able to resist an increase in blood pressure induced by a long stay on a high-salt diet, but in primates under such conditions, the initial manifestations of functional and structural rearrangement of the heart can be observed.