Retinoprotective Effect of Wild Olive (Acebuche) Oil-Enriched Diet against Ocular Oxidative Stress Induced by Arterial Hypertension

Abstract

Oxidative stress plays an important role in the pathogenesis of ocular diseases, including hypertensive eye diseases. The beneficial effects of olive oil on cardiovascular diseases might rely on minor constituents. Currently, very little is known about the chemical composition and/or therapeutic effects of the cultivated olive tree’s counterpart, wild olive (also known in Spain as acebuche—ACE). Here, we aimed to analyze the antioxidant and retinoprotective effects of ACE oil on the eye of hypertensive mice made hypertensive via administration of NG-nitro-L-arginine-methyl-ester (L-NAME), which were subjected to a dietary supplementation with either ACE oil or extra virgin olive oil (EVOO) for comparison purposes. Deep analyses of major and minor compounds present in both oils was accompanied by blood pressure monitoring, morphometric analyses, as well as different determinations of oxidative stress-related parameters in retinal layers. Aside from its antihypertensive effect, an ACE oil-enriched diet reduced NADPH (nicotinamide adenine dinucleotide phosphate) oxidase activity/gene/protein expression (with a major implication of NADPH oxidase (NOX)2 isoform) in the retinas of hypertensive mice. Supplementation with ACE oil in hypertensive animals also improved alterations in nitric oxide bioavailability and in antioxidant enzyme profile. Interestingly, our findings show that the use of ACE oil resulted in better outcomes, compared with reference EVOO, against hypertension-related oxidative retinal damage.

Anti-Inflammatory Action of Dietary Wild Olive (Acebuche) Oil in the Retina of Hypertensive Mice

“…SBP and DBP values obtained at the end of the treatment indicate the presence of severe hypertension in our study design, according to current guidelines on AH [45]. As previously reported, no significant (p > 0.05) effects on feeding behavior or weight gain were observed between normotensive and hypertensive mice after a 6-week period of feeding oil-enriched diets [19]. Our research group was pioneer in describing a blood pressure lowering effect of ACE oil in mice treated with L-NAME, showing a preferential action of this "wild origin" oil compared to a parallel EVOO-enriched diet.…”

“…•− ) and by modulating the enzymes NADPH oxidase and nitric oxide synthase, among others [19]. Therefore, ACE oil and EVOO-based diets could represent a strategical tool to reduce AH-related ocular damage in pathologies such AMD, DR or hypertensive retinopathy, among others.…”

“…Therefore, the small amounts of commercially available ACE oil are typically consumed as “gourmet” products that are generally recognized as spicier, more bitter and fruitier than standard EVOOs, possibly due to slight differences in minor compounds [ 16 , 17 ]. Some of the first evidences have attributed a higher content of tocopherols (e.g., vitamin E), sterols and triterpene acids in ACE oil than in EVOO, and also a higher amount of secoiridoid compounds relative to ortodiphenols in the former [ 18 , 19 ]. Moreover, ACE oil has been reported to have lower antigenic and allergenic capacities compared to cultivated olive trees [ 20 ].…”

“…In this regard, we have recently demonstrated a retinoprotective action of EVOO- and ACE oil-enriched diets, showing better results in the latter case, in a context of arterial hypertension (AH). The beneficial actions of these oils were ascribed to their capacity to counteract the progression of hypertensive eye disease by reducing superoxide anions (O 2 ·− ) and by modulating the enzymes NADPH oxidase and nitric oxide synthase, among others [ 19 ]. Therefore, ACE oil and EVOO-based diets could represent a strategical tool to reduce AH-related ocular damage in pathologies such AMD, DR or hypertensive retinopathy, among others.…”

Oxidative Stress in Vascular Pathophysiology: Still Much to Learn

“…Santana-Garrido et al [ 14 ] evaluate the therapeutic powder of a wild olive oil-enriched diet for the treatment of ocular oxidative stress induced by hypertension. The authors investigate the beneficial effects of ACEBUCHE, the oil obtained from the traditionally cultivated olive tree counterpart.…”