Effects of Virgin Olive Oil on Blood Pressure and Renal Aminopeptidase Activities in Male Wistar Rats

Abstract

High saturated fat diets have been associated with the development of obesity and hypertension, along with other pathologies related to the metabolic syndrome. In contrast, the Mediterranean diet, characterized by its high content of monounsaturated fatty acids, has been proposed as a dietary factor capable of positively regulating cardiovascular function. These effects have been linked to changes in the local renal renin angiotensin system (RAS) and the activity of the sympathetic nervous system. The main goal of this study was to analyze the role of two dietary fat sources on aminopeptidases activities involved in local kidney RAS. Male Wistar rats (six months old) were fed during 24 weeks with three different diets: the standard diet (S), the standard diet supplemented with virgin olive oil (20%) (VOO), or the standard diet enriched with butter (20%) plus cholesterol (0.1%) (Bch). Kidney samples were separated in medulla and cortex for aminopeptidase activities (AP) assay. Urine samples were collected for routine analysis by chemical tests. Aminopeptidase activities were determined by fluorometric methods in soluble (sol) and membrane-bound (mb) fractions of renal tissue, using arylamide derivatives as substrates. After the experimental period, the systolic blood pressure (SBP) values were similar in standard and VOO animals, and significantly lower than in the Bch group. At the same time, a significant increase in GluAP and IRAP activities were found in renal medulla of Bch animals. However, in VOO group the increase of GluAP activity in renal medulla was lower, while AspAP activity decreased in the renal cortex. Furthermore, the VOO diet also affected other aminopeptidase activities, such as TyrAP and pGluAP, related to the regulation of the sympathetic nervous system and the metabolic rate. These results support the beneficial effect of VOO in the regulation of SBP through changes in local AP activities of the kidney.

High-Fat Diets Modify the Proteolytic Activities of Dipeptidyl-Peptidase IV and the Regulatory Enzymes of the Renin–Angiotensin System in Cardiovascular Tissues of Adult Wistar Rats

“…With the VOO diet, they do not increase their body weight, they do not increase the values of systolic blood pressure (SBP), and they maintain normal values of triglycerides and the fraction of VLDL cholesterol, reduce total cholesterol and its LDL fraction, and reduce oxidative stress and lipid peroxidation against the pernicious effects that the Bch diet manifests. [4,7,9]. Elevated plasma cholesterol levels are another important risk factor widely recognized for its relationship with angiotensin metabolism [4,5,7,10,12,72], with Mediterranean countries showing lower rates of heart disease than other countries due to the usual diet rich in olive oil [75].…”

“…[4,7,9]. Elevated plasma cholesterol levels are another important risk factor widely recognized for its relationship with angiotensin metabolism [4,5,7,10,12,72], with Mediterranean countries showing lower rates of heart disease than other countries due to the usual diet rich in olive oil [75].…”

“…However, trials involving the Mediterranean diet indicate that monounsaturated fatty acids (MUFAs) are more effective than low-fat and low-cholesterol diets in preventing cardiovascular mortality and coronary artery disease [3]. The reduction in SAFA in substitution by MUFA attenuates the increase in blood pressure (BP) [4]. These alterations, depending on the degree of fatty acid saturation, are related to changes in the systemic or local renin-angiotensin systems (RAS) [5][6][7][8][9][10].…”

“…These alterations, depending on the degree of fatty acid saturation, are related to changes in the systemic or local renin-angiotensin systems (RAS) [5][6][7][8][9][10]. The activation of the RAS participates in the development of MetS, heart failure [11], and pathophysiology of hypertension [4,7,[12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Within these local RAS, the type of fatty acids consumed with the diet allows modifying various enzymes of the aminopeptidase We hypothesized that the inclusion of MUFA in the diet could be a preventive dietary factor for reducing the activation of the RAS pathway through angiotensinases and maintaining the functional integrity of cardiovascular structures.…”

“…These alterations, depending on the degree of fatty acid saturation, are related to changes in the systemic or local renin–angiotensin systems (RAS) [ 5 , 6 , 7 , 8 , 9 , 10 ]. The activation of the RAS participates in the development of MetS, heart failure [ 11 ], and pathophysiology of hypertension [ 4 , 7 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. Within these local RAS, the type of fatty acids consumed with the diet allows modifying various enzymes of the aminopeptidase (AP) family, also called angiotensinases, responsible for metabolizing angiotensin peptides (Ang) [ 5 , 9 , 26 ].…”