Abstract
Background and Aims
It is traditionally believed that high consumption of sodium chloride leads to the development of arterial hypertension, which, in turn, will cause heart remodeling. However, more and more evidence is accumulating that a high sodium chloride content in the diet can cause heart damage without increasing blood pressure (BP). This is confirmed in experiments on rats. In addition, in animals of this species, supplementing a high-salt diet with soy proteins can prevent cardiovascular damage. Whether such mechanisms operate in primates remains unclear.
Method
The study was performed on male Macacus fascicularis. Monkeys were included in the experiment at the age of 4.6 -7.0 years and had a body weight of 5,5-7,5kg. Animals were divided into 3 groups. The first (control) included 5 animals, received standard ration; the second – 5 animals, received diet with high sodium chloride content (8 g NaCl/1 kg of the feed); the third – 6 animals, who were on a diet with high salt contents supplemented by soya isolated proteins (200 g/kg of the feed). In anesthetized animals measured blood pressure and performed an echocardiographic investigation. Follow up period lasted four month.
Results
Initially, in all groups of animals, blood pressure levels (Mean(SEM)) and echocardiographic parameters did not significantly differ. During the observation period, the studied parameters did not change much. For example, in the first group, an ejection fraction (EF) increased from 61.7(1.67) to 71.6(4.74), %; P=0.045. In the same group, a tendency toward a decrease in the left ventricle end-systolic dimension (1.50(0.056)vs 1.29(0.118), mm; P=0.079) was noted. Whereas the level of systolic and diastolic blood pressures in this group (for example, systolic BP: 115.4(3.95)vs 126.0(5.39), mm Hg; P=0.134) as well as in other groups of monkeys did not change significantly. Nevertheless, after four months of observation, the level of systolic blood pressure in the second group (126.0(5.39) mm Hg) of animals was significantly higher than in the first (103.0(5.54), P=0.0118) and nonsignificantly - in the third (104.0(8.39), mm Hg; P=0.065). EF in the end of follow up period in second group (71.6(4.74%) was significantly higher than in control (58.1(2.72),%; P=0.039) but not in the third group (60.9(5.03),%; P=0.162). Tricuspid annular plane systolic excursion in second group (1.02(0.08), mm) had an insignificant tendency to increase in comparison to the first (0.782(0.096), mm; P=0.094) or third (0.818(0.049), mm; P=0.052) groups.
Conclusion
Our data do not exclude the possibility that a high salt content in the food of lower primates can contribute to an increase in blood pressure and a change in heart function. However, to resolve the issues of the relationship between changes in heart function and the level of blood pressure and the presence of the cardioprotective effect of soy proteins under these conditions, longer observations are needed.
Determination of cadmium in foods containing with high sodium chloride content by coprecipitation with zirconium hydroxide.