Recent evidence suggests that the reason Extra Virgin Olive Oil (EVOO) lowers blood pressure and reduces the risk of developing hypertension is partly due to minor components of EVOO, such as phenols. However, little is still known about the mechanism(s) through which EVOO phenols mediate anti-hypertensive effects. The aim of the present study was to investigate the mechanisms of action of EVOO phenols on mesenteric resistance arteries. A pressure myograph was used to test the effect of EVOO phenols on isolated mesenteric arteries in the presence of specific inhibitors of: (1) BKca channels (Paxillin, 10⁻⁵ M); (2) L-type calcium channels (Verapamil, 10⁻⁵ M); (3) Ryanodine receptor, RyR (Ryanodine, 10⁻⁵ M); (4) inositol 1,4,5-triphosphate receptor, IP3R, (2-Aminoethyl diphenylborinate, 2-APB, 3 × 10⁻³ M); (5) phospholipase C, PLC, (U73122, 10⁻⁵ M), and (6) GPCR-G_αi signaling, (Pertussis Toxin, 10⁻⁵ M). EVOO phenols induced vasodilation of mesenteric arteries in a dose-dependent manner, and this effect was reduced by pre-incubation with Paxillin, Verapamil, Ryanodine, 2-APB, U73122, and Pertussis Toxin. Our data suggest that EVOO phenol-mediated vasodilation requires activation of BKca channels potentially through a local increase of subcellular calcium microdomains, a pivotal mechanism on the base of artery vasodilation. These findings provide novel mechanistic insights for understanding the vasodilatory properties of EVOO phenols on resistance arteries.

Accumulating evidence has shown the beneficial health effects of extra virgin olive oil (EVOO) consumption in reducing blood pressure and preventing the risk of developing hypertension. Some studies associate the hypotensive activity of EVOO to a minor component—the phenols. This study was designed to investigate the effects of EVOO phenols on the rat resistance mesenteric artery (MA) and to find out the possible vascular pathways involved. The experiments were carried out using a pressurized myograph, which allowed the effects of phenols on isolated MA to be tested under different conditions: (a) with endothelium removed; (b) with inhibition of nitric oxide synthase by N_ω-Nitro-l-arginine methyl ester hydrochloride (l-NAME, 10⁻⁴ M) + N_ω-Nitro-l-arginine (l-NNA, 10⁻⁴ M); (c) with inhibition of cyclooxygenase by indomethacin (10⁻⁵ M); (d) with inhibition of guanylate cyclase by 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ,10⁻⁵ M) or adenylate cyclase by 9-(Tetrahydro-2′-furyl)adenine (SQ, 10⁻⁵ M); (e) with depolarization by high potassium chloride (40 mM); and (f) with inhibition of the large conductance Ca²⁺–potassium channels (BK_Ca2+) with paxilline (10⁻⁵ M). EVOO phenols induce vasodilation of the endothelium, mediated by a direct effect on smooth muscle cells (SMC) by activation of BK_Ca2+ channels, an action by which phenols can regulate the vascular tone of the resistance artery. Phenols can be regarded as bioactive molecules that may contribute to the antihypertensive effects of EVOO.

Placental protein 13 (PP13) exhibits a plasma concentration that increases gradually during normal gestation, a process that is disrupted in preeclampsia, which is characterized by elevated vascular resistance, reduced utero-placental blood flow, and intrauterine growth restriction. This study investigated PP13’s role in vascular tone regulation and its molecular mechanisms. Uterine and subcutaneous arteries, isolated from both pregnant and non-pregnant women, were precontracted with the thromboxane analogue U46619 and exposed to PP13 using pressurized myography. The molecular mechanisms were further investigated, using specific inhibitors for nitric oxide synthase (L-NAME+LNNA at 10⁻⁴ M) and guanylate cyclase (ODQ at 10⁻⁵ M). The results showed that PP13 induced vasodilation in uterine arteries, but not in subcutaneous arteries. Additionally, PP13 counteracted U46619-induced vasoconstriction, which is particularly pronounced in pregnancy. Further investigation revealed that PP13’s mechanism of action is dependent on the activation of the nitric oxide–cGMP pathway. This study provides novel insights into the vasomodulatory effects of PP13 on human uterine arteries, underscoring its potential role in regulating utero-placental blood flow. These findings suggest that PP13 may be a promising candidate for improving utero-placental blood flow in conditions such as preeclampsia. Further research and clinical studies are warranted to validate PP13’s efficacy and safety as a therapeutic agent for managing preeclampsia.

During pregnancy, uterine vasculature undergoes significant circumferential growth to increase uterine blood flow, vital for the growing feto-placental unit. However, this process is often compromised in conditions like maternal high blood pressure, particularly in preeclampsia (PE), leading to fetal growth impairment. Currently, there is no cure for PE, partly due to the adverse effects of anti-hypertensive drugs on maternal and fetal health. This study aimed to investigate the vasodilator effect of extra virgin olive oil (EVOO) phenols on the reproductive vasculature, potentially benefiting both mother and fetus. Isolated uterine arteries (UAs) from pregnant rats were tested with EVOO phenols in a pressurized myograph. To elucidate the underlying mechanisms, additional experiments were conducted with specific inhibitors: L-NAME/L-NNA (10⁻⁴ M) for nitric oxide synthases, ODQ (10⁻⁵ M) for guanylate cyclase, Verapamil (10⁻⁵ M) for the L-type calcium channel, Ryanodine (10⁻⁵ M) + 2-APB (3 × 10⁻⁵ M) for ryanodine and the inositol triphosphate receptors, respectively, and Paxilline (10⁻⁵ M) for the large-conductance calcium-activated potassium channel. The results indicated that EVOO-phenols activate Ca²⁺ signaling pathways, generating nitric oxide, inducing vasodilation via cGMP and BKCa²⁺ signals in smooth muscle cells. This study suggests the potential use of EVOO phenols to prevent utero-placental blood flow restriction, offering a promising avenue for managing PE.

Placental protein 13 (PP13) exhibits a plasma concentration that increases gradually during normal gestation, a process disrupted in preeclampsia, characterized by elevated vascular resistance, re-duced utero-placental blood flow and intrauterine growth restriction. This study investigated PP13’s role in vascular tone regulation and its molecular mechanisms. Uterine and subcutaneous arteries isolated from both pregnant and non-pregnant women were precontracted with the thromboxane analogue U46619, and exposed to PP13 using pressurized myography. The molecular mechanisms were further investigated using specific inhibitors for ni-tric oxide synthase (L-NAME+LNNA at 10-4 M) and guanylate cyclase (ODQ at 10-5 M). Results showed PP13 induced vasodilation in uterine arteries but not in subcutaneous arteries. Ad-ditionally, PP13 counteract U46619-induced vasoconstriction, which is particularly pronounced in pregnancy. Further investigation revealed that PP13's mechanism of action is dependent on activa-tion of the Nitric oxide-cGMP pathway. This study provides novel insights into the vasomodulatory effects of PP13 on human uterine ar-teries, underscoring its potential role in regulating utero-placental blood flow. These findings suggest PP13 may be a promising candidate for improving utero-placental blood flow in condi-tions such as preeclampsia. Further research and clinical studies are warranted to validate PP13's efficacy and safety as a therapeutic agent for managing preeclampsia.