In response to endothelial cell activation, arachidonic acid can be converted by cytochrome P450 (CYP) epoxygenases to epoxyeicosatrienoic acids (EETs), which have potent vasodilator and anti-inflammatory properties. EETs are rapidly degraded in vivo to the less active dihydroxyeicosatrienoic acids (DHETs) by soluble epoxide hydrolase (sEH). Since the beginning of the 2000s, the role of EET pathway in human health and its alteration in diseases has been shown by measuring EETs/DHET levels in blood, by evaluating the relationship between CYP/sEH gene polymorphisms, which modify enzyme activity and thus EETs/DHET level, and by assessing the inhibitory effect of the local administration of CYP epoxygenase inhibitor on endothelium-dependent dilatation. By combining these functional and biological approaches, we demonstrated that EETs are the endothelial factors released by CYP epoxygenases involved in the flow-mediated dilatation of conduit arteries in healthy subjects, together with the impairment of EET availability in essential hypertensive patients at this level. The modulation of EET pathway now emerges as a new promising pharmacological target that may improve the clinical management of patients at high cardiovascular risk. In this respect, the restoration of EET availability using a new class of agents, the inhibitors of sEH, gave promising results in various animal models of cardiovascular diseases, reducing blood pressure and target organ damage, and a first product has entered clinical evaluation.

This study addressed the hypothesis that inhibiting the soluble epoxide hydrolase (sEH)-mediated degradation of epoxy-fatty acids, notably epoxyeicosatrienoic acids, has an additional impact against cardiovascular damage in insulin resistance, beyond its previously demonstrated beneficial effect on glucose homeostasis. The cardiovascular and metabolic effects of the sEH inhibitor trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid ( t-AUCB; 10 mg/l in drinking water) were compared with those of the sulfonylurea glibenclamide (80 mg/l), both administered for 8 wk in FVB mice subjected to a high-fat diet (HFD; 60% fat) for 16 wk. Mice on control chow diet (10% fat) and nontreated HFD mice served as controls. Glibenclamide and t-AUCB similarly prevented the increased fasting glycemia in HFD mice, but only t-AUCB improved glucose tolerance and decreased gluconeogenesis, without modifying weight gain. Moreover, t-AUCB reduced adipose tissue inflammation, plasma free fatty acids, and LDL cholesterol and prevented hepatic steatosis. Furthermore, only the sEH inhibitor improved endothelium-dependent relaxations to acetylcholine, assessed by myography in isolated coronary arteries. This improvement was related to a restoration of epoxyeicosatrienoic acid and nitric oxide pathways, as shown by the increased inhibitory effects of the nitric oxide synthase and cytochrome P-450 epoxygenase inhibitors l-NA and MSPPOH on these relaxations. Moreover, t-AUCB decreased cardiac hypertrophy, fibrosis, and inflammation and improved diastolic function, as demonstrated by the increased E/A ratio (echocardiography) and decreased slope of the end-diastolic pressure-volume relation (invasive hemodynamics). These results demonstrate that sEH inhibition improves coronary endothelial function and prevents cardiac remodeling and diastolic dysfunction in obese insulin-resistant mice.

Middle molecular weight uraemic toxins are considered to play an important role in vascular dysfunction and cardiovascular outcomes in end-stage renal disease (ESRD) patients. Recent dialysis techniques based on convection, specifically high-efficiency on-line haemodiafiltration (HDF), enhance the removal of middle molecular weight toxins and reduce all-cause mortality in haemodialysis (HD) patients. However, the mechanisms of these improved outcomes remain to be established. This prospective study randomly assigned 42 ESRD patients to switch from high-flux HD to high-efficiency on-line HDF (n = 22) or to continue HD (n = 20). Brachial artery endothelium-dependent flow-mediated dilatation, central pulse pressure, carotid artery intima-media thickness (IMT), internal diastolic diameter and distensibility and circulating markers of uraemia, inflammation and oxidative stress were blindly assessed before and after a 4-month follow-up. Brachial flow-mediated dilatation and carotid artery distensibility increased significantly in the HDF group compared with HD, while carotid IMT and diameter remained similar. HDF decreased predialysis levels of the uraemic toxins β2-microglobulin, phosphate and blood TNFα mRNA expression. Oxidative stress markers were not different between the HD and HDF groups. Blood mRNA expression of protein kinase C β2, an endothelial NO-synthase (eNOS) inhibitor, decreased significantly with HDF. High-efficiency on-line HDF prevents the endothelial dysfunction and stiffening of the conduit arteries in ESRD patients compared with high-flux HD. HDF decreases uraemic toxins, vascular inflammation, and is associated with subsequent improvement in eNOS functionality. These results suggest that reduced endothelial dysfunction may be an intermediate mechanism explaining the beneficial outcomes associated with HDF.

Background and Aims: Increasing evidence suggests that COVID-19 survivors experience long-term cardiovascular complications possibly through development of vascular damage. The study aimed to investigate whether accelerated vascular ageing occurs after COVID-19 infection, and if so, identify its determinants. Methods: This prospective, multicentric, cohort study, included 34 centres in 16 countries worldwide, in 4 groups of participants—COVID-19-negative controls (ⅰ) and three groups of individuals with recent (6 ± 3 months) exposure to SARS-CoV-2: not hospitalized (ⅱ), hospitalized in general wards (ⅲ), and hospitalized in intensive care units (ⅳ). The main outcome was carotid-femoral pulse wave velocity (PWV), an established biomarker of large artery stiffness. Results: 2390 individuals (age 50 ± 15 years, 49.2% women) were recruited. After adjustment for confounders, all COVID-19-positive groups showed higher PWV (+0.41, +0.37, and +0.40 m/s for groups 2–4, P < .001, P = .001 and P = .003) vs. controls [PWV 7.53 (7.09; 7.97) m/s adjusted mean (95% CI)]. In sex-stratified analyses, PWV differences were significant in women [PWV (+0.55, +0.60, and +1.09 m/s for groups 2–4, P < .001 for all)], but not in men. Among COVID-19 positive women, persistent symptoms were associated with higher PWV, regardless of disease severity and cardiovascular confounders [adjusted PWV 7.52 (95% CI 7.09; 7.96) vs. 7.13 (95% CI 6.67; 7.59) m/s, P < .001]. A stable or improved PWV after 12 months was found in the COVID+ groups, whereas a progression was observed in the COVID− group. Conclusions: COVID-19 is associated with early vascular ageing in the long term, especially in women.