Cardioprotective Effect of Soy Protein on a High-Salt Diet in Cynomolgus Monkeys

Excessive salt intake is accompanied by the development of cardiovascular disorders, not always associated with an increase in blood pressure (BP). Given the cardioprotective effect of soy proteins in chronic kidney disease, the question arose of the possibility of leveling dietary interventions, in particular soy proteins, the damaging effect of a high-salt diet on the cardiovascular system. The aim of this work is to study the effect of long-term use of a diet high in NaCl and soy protein on myocardial remodeling and skin histomorphology in monkeys. The study was performed on male Javan macaques (Macaca fascicularis). The control group received a standard diet (2 g NaCl/kg feed). The second was a high-salt diet (8 g NaCl/kg feed), the third was a high-salt diet and SUPRO760 soy protein (200 g/kg feed). Echocardiography, registration of BP and heart rate were performed at baseline, after 4 and 12 months. After 12 months, a histological examination of the musculocutaneous flap was performed. In all animals, BP and heart rate did not change significantly during 12 months. In macaques on a high-salt diet, by the end of the study, deterioration in systolic and diastolic functions of the left ventricle (LV) was noted. In animals receiving additional soy protein, these changes leveled out. After 12 months, macaques fed soy protein had LV myocardial mass smaller and higher LV contractility than animals fed excess salt without soy protein. In monkeys on a high-salt diet, accumulation of collagen fibers in the hypodermis, hyalinization of the cytoplasm of capillary smooth muscle cells, perivascular and perineural edema of the reticular dermis were revealed. In animals treated with soy protein, skin capillary remodeling was less pronounced. Thus, high salt intake leads to adverse structural and functional disorders of the heart and blood vessels in cynomolgus monkeys, not associated with an increase in blood pressure. The inclusion of soy isolate in the diet reduces the negative effects of a high-salt diet on the cardiovascular system.