Daily consumption of wild olive (acebuche) oil reduces blood pressure and ameliorates endothelial dysfunction and vascular remodelling in rats with NG-nitro-L-arginine methyl ester-induced hypertension.

Alfonso Mate,M Carmen Pérez-Camino,Álvaro Santana-Garrido,Carmen M Vázquez,Gema Aguilar-Espejo,Claudia Reyes-Goya

doi:10.1017/s0007114522000034

Abstract

Despite numerous reports on the beneficial effects of olive oil in the cardiovascular context, very little is known about the olive tree's wild counterpart (Olea europaea, L. var. sylvestris), commonly known as acebuche (ACE) in Spain. The aim of this study was to analyse the possible beneficial effects of an extra virgin ACE oil on vascular function in a rodent model of arterial hypertension (AH) induced by NG-nitro-l-arginine methyl ester (L-NAME). Four experimental groups of male Wistar rats were studied: (1) normotensive rats (Control group); (2) normotensive rats fed a commercial diet supplemented with 15 % (w/w) ACE oil (Acebuche group); (3) rats made hypertensive following administration of L-NAME(L-NAME group); and (4) rats treated with L-NAME and simultaneously supplemented with 15 % ACE oil (LN + ACE group). All treatments were maintained for 12 weeks. Besides a significant blood pressure (BP)-lowering effect, the ACE oil-enriched diet counteracted the alterations found in aortas from hypertensive rats in terms of morphology and responsiveness to vasoactive mediators. In addition, a decrease in hypertension-related fibrotic and oxidative stress processes was observed in L-NAME-treated rats subjected to ACE oil supplement. Therefore, using a model of AH via nitric oxide depletion, here we demonstrate the beneficial effects of a wild olive oil based upon its vasodilator, antihypertensive, antioxidant, antihypertrophic and antifibrotic properties. We postulate that regular inclusion of ACE oil in the diet can alleviate the vascular remodelling and endothelial dysfunction processes typically found in AH, thus resulting in a significant reduction of BP.

Highlights

The traditional Mediterranean diet is generally based on grains, cereals, vegetables, nuts, fruits, meat, fish, moderate consumption of milk, low-to-moderate wine consumption and use of olive oil as the main source of fat
Beneficial effects of polyphenol-enriched diets have been reported in the setting of diabetes, the metabolic syndrome, cancer, and cardiovascular and degenerative diseases, based on the antioxidant, anti-inflammatory and Abbreviations: ACE, acebuche; ACh, acetylcholine; Arterial hypertension (AH), arterial hypertension; BP, blood pressure; DHE, dihydroethidium; eNOS, endothelial nitric oxide synthase; extra virgin olive oils (EVOO), extra virgin olive oil; L-NAME, NG-nitro-L-arginine methyl ester; spontaneously hypertensive rats (SHR), spontaneously hypertensive rat; SOD, superoxide dismutase; TGF-β1, transforming growth factor beta 1; VOO, virgin olive oil
Olive tree ancestors seem to have lower allergenicity than the widely distributed cultivated lineages, and preliminary studies found a higher amount of tocopherols and sterols in ACE oil compared with standard extra virgin olive oils (EVOO)(25,26)

Summary

Introduction

The traditional Mediterranean diet is generally based on grains, cereals, vegetables, nuts, fruits, meat, fish, moderate consumption of milk, low-to-moderate wine consumption and use of olive oil as the main source of fat. Beneficial effects of polyphenol-enriched diets have been reported in the setting of diabetes, the metabolic syndrome (excessive body weight/adiposity, dyslipidaemia, hypertension and hyperglycaemia/insulin resistance), cancer, and cardiovascular and degenerative diseases, based on the antioxidant, anti-inflammatory and Abbreviations: ACE, acebuche; ACh, acetylcholine; AH, arterial hypertension; BP, blood pressure; DHE, dihydroethidium; eNOS, endothelial nitric oxide synthase; EVOO, extra virgin olive oil; L-NAME, NG-nitro-L-arginine methyl ester; SHR, spontaneously hypertensive rat; SOD, superoxide dismutase; TGF-β1, transforming growth factor beta 1; VOO, virgin olive oil. Arterial hypertension (AH) has long been recognised as one of the most powerful risk factors for cardiovascular events, including myocardial infarction, stroke, heart failure and chronic renal failure[28] In this sense, and besides the wide range of antihypertensive drugs, promoting a healthy lifestyle that includes nutraceutical foods such as ACE oil might help control blood pressure (BP)(27). Seven isoforms (NOX1–5 and Duox1–2) of the catalytic subunit of this enzyme complex are differentially expressed in the body[30], of which isoforms NOX1, 2, 4 and 5 are predominant in vascular cells[31]

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