Nitric Oxide Bioavailability Research Articles

Inflammatory Mediators of Endothelial Dysfunction.

Endothelial dysfunction (ED) is characterized by imbalanced vasodilation and vasoconstriction, elevated reactive oxygen species (ROS), and inflammatory factors, as well as deficiency of nitric oxide (NO) bioavailability. It has been reported that the maintenance of endothelial cell integrity serves a significant role in human health and disease due to the involvement of the endothelium in several processes, such as regulation of vascular tone, regulation of hemostasis and thrombosis, cell adhesion, smooth muscle cell proliferation, and vascular inflammation. Inflammatory modulators/biomarkers, such as IL-1α, IL-1β, IL-6, IL-12, IL-15, IL-18, and tumor necrosis factor α, or alternative anti-inflammatory cytokine IL-10, and adhesion molecules (ICAM-1, VCAM-1), involved in atherosclerosis progression have been shown to predict cardiovascular diseases. Furthermore, several signaling pathways, such as NLRP3 inflammasome, that are associated with the inflammatory response and the disrupted H2S bioavailability are postulated to be new indicators for endothelial cell inflammation and its associated endothelial dysfunction. In this review, we summarize the knowledge of a plethora of reviews, research articles, and clinical trials concerning the key inflammatory modulators and signaling pathways in atherosclerosis due to endothelial dysfunction.

Cytokine storm in individuals with severe COVID-19 decreases endothelial cell antioxidant defense via Downregulation of the Nrf2 transcriptional factor.

The cytokine storm in SARS-CoV-2 infection contributes to the onset of inflammation and target organ damage. The endothelium is a key player in COVID-19 pathophysiology and it is an important target for cytokines. Since cytokines trigger oxidative stress and negatively impact endothelial cell function, we sought to determine whether serum derived from severe COVID-19 individuals decreases endothelial cells' main antioxidant defense, i.e. the antioxidant transcriptional factor Nrf2. Human umbilical vein endothelial cells (HUVEC) were incubated with severe COVID-19 serum at different time points and the effects on redox balance and Nrf2 activity were determined. Serum from COVID-19 individuals increased oxidant species, as indicated by higher DHE oxidation, increased protein carbonylation and augmented mitochondrial reactive oxygen species (ROS) generation and dysfunction. COVID-19 serum, in comparison with serum from healthy individuals, induced cell death and diminished nitric oxide (NO) bioavailability. In parallel, Nrf2 nuclear accumulation and the expression of Nrf2-targeted genes were reduced in endothelial cells exposed to serum from COVID-19 individuals. Additionally, these cells exhibited higher expression of Bach-1, a negative regulator of Nrf2 that competes for DNA binding. All events were prevented by Tocilizumab, an IL-6 receptor blocker, indicating that IL-6 is key to the impairment of endothelial antioxidant defense. In conclusion, endothelial dysfunction related to SARS-Cov-2 infection is linked to an IL-6-dependent decrease in the endothelial antioxidant defense. Pharmacological activation of Nrf2 may decrease endothelial cell damage in individuals with severe COVID-19.

Significance of Endothelial Dysfunction Amelioration for Sodium-Glucose Cotransporter 2 Inhibitor-Induced Improvements in Heart Failure and Chronic Kidney Disease in Diabetic Patients.

Beyond lowering plasma glucose levels, sodium-glucose cotransporter 2 inhibitors (SGLT2is) significantly reduce hospitalization for heart failure (HF) and retard the progression of chronic kidney disease (CKD) in patients with type 2 diabetes. Endothelial dysfunction is not only involved in the development and progression of cardiovascular disease (CVD), but is also associated with the progression of CKD. In patients with type 2 diabetes, hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia induce the development of endothelial dysfunction. SGLT2is have been shown to improve endothelial dysfunction, as assessed by flow-mediated vasodilation, in individuals at high risk of CVD. Along with an improvement in endothelial dysfunction, SGLT2is have been shown to improve oxidative stress, inflammation, mitochondrial dysfunction, glucotoxicity, such as the advanced signaling of glycation end products, and nitric oxide bioavailability. The improvements in endothelial dysfunction and such endothelium-derived factors may play an important role in preventing the development of coronary artery disease, coronary microvascular dysfunction and diabetic cardiomyopathy, which cause HF, and play a role in retarding CKD. The suppression of the development of HF and the progression of CKD achieved by SGLT2is might have been largely induced by their capacity to improve vascular endothelial function.

Hyperuricemia: A key contributor to endothelial dysfunction in cardiovascular diseases.

As an end product of purine metabolism, uric acid (UA) is a major endogenous antioxidant in humans. However, impaired UA synthesis and excretion can lead to hyperuricemia (HUA), which may in turn induce endothelial dysfunction (ED) and contribute to the pathogenesis of cardiovascular diseases (CVDs; e.g., atherosclerosis and hypertension). In this review, we discuss recent advances and novel insights into the effects exerted by HUA conditions in ED and related underlying mechanisms focusing on impaired UA metabolism, reduction in the synthesis and bioavailability of nitric oxide, endothelial cell injury, the endothelial-to-mesenchymal transition, insulin resistance, procoagulant activity, and acquisition of an inflammatory phenotype. We additionally discuss intervention strategies for HUA-induced ED and the paradoxical roles of UA in endothelial function. We summarize major conclusions and perspectives: the deleterious effects of HUA contribute to the initiation and progression of CVD-related ED. However, the treatment strategies (in addition to urate-lowering therapy) for increasing endothelial function are limited because the majority of literature on pharmacological and pathophysiological mechanisms underlying HUA-induced ED solely describes in vitro models. Therefore, a better understanding of the mechanisms involved in HUA-induced ED is critical to the development of novel therapies for preventing and treating CVD-HUA comorbidities.

A Critical Review on Vasoactive Nutrients for the Management of Endothelial Dysfunction and Arterial Stiffness in Individuals under Cardiovascular Risk.

Pathophysiological conditions such as endothelial dysfunction and arterial stiffness, characterized by low nitric oxide bioavailability, deficient endothelium-dependent vasodilation and heart effort, predispose individuals to atherosclerotic lesions and cardiac events. Nitrate (NO3-), L-arginine, L-citrulline and potassium (K+) can mitigate arterial dysfunction and stiffness by intensifying NO bioavailability. Dietary compounds such as L-arginine, L-citrulline, NO3- and K+ exert vasoactive effects as demonstrated in clinical interventions by noninvasive flow-mediated vasodilation (FMD) and pulse-wave velocity (PWV) prognostic techniques. Daily L-arginine intakes ranging from 4.5 to 21 g lead to increased FMD and reduced PWV responses. Isolated L-citrulline intake of at least 5.6 g has a better effect compared to watermelon extract, which is only effective on endothelial function when supplemented for longer than 6 weeks and contains at least 6 g of L-citrulline. NO3- supplementation employing beetroot at doses greater than 370 mg promotes hemodynamic effects through the NO3--NO2-/NO pathway, a well-documented effect. A potassium intake of 1.5 g/day can restore endothelial function and arterial mobility, where decreased vascular tone takes place via ATPase pump/hyperpolarization and natriuresis, leading to muscle relaxation and NO release. These dietary interventions, alone or synergically, can ameliorate endothelial dysfunction and should be considered as adjuvant therapies in cardiovascular diseases.

Sildenafil attenuates oxidative stress and endothelial dysfunction in lead-induced hypertension.

Lead (Pb) reduces NO bioavailability, impairs the antioxidant system, and increases the generation of reactive oxygen species (ROS). Pb-induced oxidative stress may be responsible for the associated endothelial dysfunction. Sildenafil has shown nitric oxide (NO)-independent action, including antioxidant effects. Therefore, we examined the effects of sildenafil on oxidative stress, reductions of NO and endothelial dysfunction in Pb-induced hypertension. Wistar rats were distributed into three groups: Pb, Pb + sildenafil and Sham. Blood pressure and endothelium-dependent vascular function were recorded. We also examined biochemical determinants of lipid peroxidation and antioxidant function. ROS levels, NO metabolites and NO levels in human umbilical vein endothelial cells (HUVECs) were also evaluated. Sildenafil prevents impairment of endothelium-dependent NO-mediated vasodilation and attenuates Pb-induced hypertension, reduces ROS formation, enhances superoxide dismutase (SOD) activity and antioxidant capacity in plasma and increases NO metabolites in plasma and HUVECs culture supernatants, while no changes were found on measurement of NO released from HUVECs incubated with plasma of the Pb and Pb + sildenafil groups compared with the sham group. In conclusion, sildenafil protects against ROS-mediated inactivation of NO, thus preventing endothelial dysfunction and attenuating Pb-induced hypertension, possibly through antioxidant effects.

Effects of beetroot juice supplementation on vascular functional and structural changes in aged mice.

This study investigated whether beetroot juice (BRJ) ingestion ameliorates aging-induced functional and structural changes in vasculature. Aged mice (98-100 weeks old) were supplemented with BRJ (nitrate: 3.5 mmol/L) or drinking water for 4 weeks and compared with young mice (12-15 weeks old). The vasorelaxant response of isolated aortas to acetylcholine was markedly weaker in aged mice than in young mice, but the attenuated relaxation was significantly improved in BRJ-supplemented aged mice. The acetylcholine-induced relaxation was completely abolished by Nω -nitro-l-arginine methyl ester in all groups. Additionally, the response to sodium nitroprusside was comparable among the three groups. The aortic medial thickness was significantly greater in aged mice than in young mice, and BRJ supplementation did not suppress this thickening. Plasma nitrate levels were significantly higher in BRJ-supplemented aged mice than in non-supplemented aged mice. Conversely, non-supplemented aged mice had high plasma levels of thiobarbituric acid-reactive substances, but the levels were suppressed in BRJ-supplemented aged mice. These findings suggest that BRJ ingestion improves vascular endothelial dysfunction associated with aging, at least in part, by enhancing nitric oxide bioavailability and reducing oxidative stress. Therefore, beetroot ingestion may be a highly useful self-medication option to prevent vascular aging.

Increased Circulating ADMA in Young Male Rats Caused Cognitive Deficits and Increased Intestinal and Hippocampal NLRP3 Inflammasome Expression and Microbiota Composition Alterations: Effects of Resveratrol.

Endothelial dysfunction is characterized by disturbances in nitric oxide (NO) bioavailability and increased circulating asymmetric dimethylarginine (ADMA) due to the enormous release of free radicals. Increased circulating ADMA may cause endothelial dysfunction and a variety of clinical disorders, such as liver and kidney disease. Young male Sprague-Dawley rats at postnatal day 17 ± 1 received continuous ADMA infusion via an intraperitoneal pump to induce endothelial dysfunction. Four groups of rats (n = 10 per group) were allocated: control, control and resveratrol, ADMA infusion, and ADMA infusion and resveratrol groups. Spatial memory, NLR family pyrin-domain-containing 3 (NLRP3) inflammasome, cytokine expression, tight junction proteins in the ileum and dorsal hippocampus, and microbiota composition were examined. We found cognitive deficits; increased NLRP3 inflammasome in the plasma, ileum, and dorsal hippocampus; decreased ileum and dorsal hippocampal cytokine activation and tight junction proteins; and microbiota composition alterations in the ADMA-infusion young male rats. Resveratrol had beneficial effects in this context. In conclusion, we observed NLRP3 inflammasome activation in peripheral and central dysbiosis in young male rats with increased circulating ADMA, and found that resveratrol had beneficial effects. Our work adds to the mounting evidence that inhibiting systemic inflammation is a promising therapeutic avenue for cognition impairment, probably via the gut-brain axis.

Reduction in blood pressure following acute dietary nitrate ingestion is correlated with increased red blood cell S-nitrosothiol concentrations

Dietary nitrate (NO3−) supplementation can enhance nitric oxide (NO) bioavailability and lower blood pressure (BP) in humans. The nitrite concentration ([NO2−]) in the plasma is the most commonly used biomarker of increased NO availability. However, it is unknown to what extent changes in other NO congeners, such as S-nitrosothiols (RSNOs), and in other blood components, such as red blood cells (RBC), also contribute to the BP lowering effects of dietary NO3−. We investigated the correlations between changes in NO biomarkers in different blood compartments and changes in BP variables following acute NO3− ingestion. Resting BP was measured and blood samples were collected at baseline, and at 1, 2, 3, 4 and 24 h following acute beetroot juice (∼12.8 mmol NO3−, ∼11 mg NO3−/kg) ingestion in 20 healthy volunteers. Spearman rank correlation coefficients were determined between the peak individual increases in NO biomarkers (NO3−, NO2−, RSNOs) in plasma, RBC and whole blood, and corresponding decreases in resting BP variables. No significant correlation was observed between increased plasma [NO2−] and reduced BP, but increased RBC [NO2−] was correlated with decreased systolic BP (rs = −0.50, P = 0.03). Notably, increased RBC [RSNOs] was significantly correlated with decreases in systolic (rs = −0.68, P = 0.001), diastolic (rs = −0.59, P = 0.008) and mean arterial pressure (rs = −0.64, P = 0.003). Fisher's z transformation indicated no difference in the strength of the correlations between increases in RBC [NO2−] or [RSNOs] and decreased systolic blood pressure. In conclusion, increased RBC [RSNOs] may be an important mediator of the reduction in resting BP observed following dietary NO3− supplementation.

Protective role of nitric oxide donors on endothelium in ischemia-reperfusion injury: a meta-analysis of randomized controlled trials

BackgroundDecreased bioavailability of nitric oxide (NO) under hypoxic conditions can lead to endothelial dysfunction. NO supplementation may protect endothelial function in ischemia-reperfusion (IR) injury. Therefore, a meta-analysis of randomized controlled trials (RCTs) was performed to verify the protective effect of NO donors on endothelium in IR injury.MethodsMedline, Embase, Cochrane Library, and Web of Science databases were searched from inception to April 1, 2023. The specific inclusion criteria were as follows: (1) RCTs; (2) trials comparing NO donors with placebo control groups; and (3) trials reporting the effects of these interventions on vascular endothelial functional outcomes in IR injury. Random-effects models were used to assess pooled effect sizes, which were expressed as standardized mean differences (SMD).ResultsSeven studies satisfied the inclusion criteria and consisted of a total of 149 participants. NO donors were protective of endothelial function in IR injury (SMD: − 1.60; 95% confidence interval [CI]: − 2.33, − 0.88, P < 0.0001; heterogeneity [I2 = 66%, P = 0.001]). Results of the subgroup analysis showed the following: absence of protective effect of NO donor use following ischemia on endothelial function in IR injury − 1.78 (95% CI: − 2.50, − 1.07) and loss of protective effect on endothelial function after prolonged NO donor use − 0.89 (95% CI: − 2.06, 0.28).ConclusionThe short-period use of NO donors before the onset of ischemia can protect endothelial function in IR injury.

Impact of Cigarette Smoking and Exercise on Arterial Stiffness: A Narrative Literature Review

PURPOSE: Smoking often causes acute and chronic cardiovascular disorders. Cigarette smoking increases oxidative stress, reduces nitric oxide bioavailability, and changes the extracellular matrix, impairing arterial stiffness. However, regular physical activity and smoking cessation significantly and rapidly reverse the detrimental effects. This narrative review summarizes the relevant research that describes the impacts of cigarette smoking on the cardiovascular system and demonstrates the therapeutic or preventative roles of exercise and smoking cessation in smoking-associated arterial stiffness.METHODS: We used scientific search engines, including PubMed, Web of Science, Google Scholar, and Wiley Online Library, to identify previous studies exploring the effects of smoking, exercise, and smoking cessation on arterial stiffness.RESULTS: We discussed the most important therapeutic and/or preventive roles of exercise and smoking cessation in decreasing arterial stiffness. Most studies have demonstrated that acute and chronic smoking increase arterial stiffness. Smoking and physical activity were negatively associated. However, this relationship was often attenuated or reversed during adult exercise interventions. In addition, smoking cessation reversed the effects of smoking on arterial stiffness.CONCLUSIONS: Smoking increases the risk of acute and chronic cardiovascular disease. Cigarette smoking deteriorates arterial stiffness by altering the vascular walls. However, regular exercise and smoking cessation can improve or prevent impaired arterial stiffness.

Asociación entre niveles de proteína C-reactiva y óxido nítrico con el pronóstico de pacientes con infarto cerebral agudo

Introducción: La inflamación y alteraciones en la biodisponibilidad del óxido nítrico (NO) han sido involucradas en la fisiopatología de la enfermedad cerebrovascular.&#x0D; Objetivo: El objetivo del estudio fue determinar el valor pronóstico de la medición de metabolitos del NO y marcadores inflamatorios en pacientes con infarto cerebral agudo.&#x0D; Materiales y métodos: Se incluyeron 158 pacientes con diagnóstico de infarto cerebral agudo en un estudio observacional de cohorte. Entre 48 y 72 horas del inicio de los síntomas se tomó una muestra de sangre para determinación del perfil bioquímico, marcadores inflamatorios (PCR, IL1-?, IL6, TNF-?) y nitritos/nitratos plasmáticos. Se realizó seguimiento durante 2 años para determinar la aparición de un nuevo evento (infarto cerebral, infarto de miocardio, falla cardiaca) o muerte de origen vascular. Un análisis de regresión multivariada de Cox permitió determinar los factores asociados independientemente con el desenlace.&#x0D; Resultados: La edad promedio fue 70,5 ± 12,8 años. El 39,2% de los sujetos incluidos presentó el desenlace durante los primeros 24 meses de seguimiento. Los niveles de PCR &gt; 12 mg/L (HR 2,22, IC 95% 1,07-4,59) y el puntaje &gt; 13 en la escala NIHSS al ingreso (HR 2,81 IC 95% 1,46-5,41) se encontraron significativamente asociados con mayor riesgo de presentar un nuevo evento. La combinación de niveles de PCR &lt; 12 mg/L y nitritos/nitratos &lt; 35,5 µmol/L se identificó como un factor protector (HR 0,21, IC 95% 0,06-0,71).&#x0D; Conclusión: Este estudio sugiere que la determinación de nitritos/nitratos en conjunto con los niveles de PCR puede ser de utilidad para estratificar el riesgo de nuevos eventos en pacientes con infarto cerebral agudo.

Nitric oxide metabolites in heart failure patients with reduced or preserved ejection fraction and effects of different exercise modes

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): German Centre for Cardiovascular Research (DZHK). Background Alterations of endothelial function and nitric oxide (NO) release are involved in pathophysiology and clinical symptoms of heart failure (HF). Regular exercise training improves vascular and endothelial function and is closely linked to mechanisms of NO pathway by enhancing endothelial NO synthesis. However, it is not well investigated how exercise training affects metabolites of the NO pathway and whether different exercise modes have different effects on NO bioavailability in HF. Purpose The aims of this analysis were to 1) investigate differences in serum levels of the NO metabolites L-arginine, homoarginine, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) between patients with HF with reduced (HFrEF) or preserved ejection fraction (HFpEF) and 2) to investigate effects of high-intensity interval training (HIIT) and moderate continuous training (MCT) on these parameters. Methods Patients with HF from two clinical exercise intervention trials were included in this analysis. In both trials, patients were randomized (1:1:1) either to HIIT, MCT or guideline control (CG). Clinical data and blood samples were collected at baseline, after three months of supervised exercise training and after 12 months follow-up. NO metabolites were analysed from EDTA-plasma using liquid chromatography-tandem mass spectrometry (LC–MS/MS). Results Data from 366 patients with HF, including 206 HFrEF (median [1. and 3. quartile]: 61 [53;70] years, 18.9% females) and 160 HFpEF patients (71 [66;76] years, 65.6% females), was available for analysis. Patients with HFrEF or HFpEF showed no significant differences in NYHA classification (NYHA III: 30.6% vs. 26.2%, p=0.43) or presence of diabetes mellitus (23.8% vs. 26.2%, p=0.50), while HFpEF had a higher prevalence of hypertension (86.9% vs. 38.5%, p&amp;lt;0.001) but a smaller number of current smoker than HFrEF (4.4% vs. 18.0%, p&amp;lt;0.001). PeakVO2 (18.4 [14.5;22.6] ml/min/kg vs. 17.0 [14.3;20.4] ml/min/kg, p=0.03) and HDL-cholesterol (56 [46;65] mg/dl vs. 42 [36;54] mg/dl, p&amp;lt;0.001) were higher in HFpEF than in HFrEF. At baseline, homoarginine and ADMA levels were higher in HFrEF than in HFpEF, but no differences in L-arginine or SDMA could be observed (Table 1). Changes in metabolite levels from baseline to 3 and 12 months were not significantly different between groups (HIIT, MCT, CG) in either HF phenotype (all p&amp;gt;0.05). In all exercise groups, median adherence to training sessions was at 85% or above with no significant differences between groups (p&amp;gt;0.05). Conclusion At baseline, patients with HFrEF had significantly higher homoarginine and ADMA levels compared to patients with HFpEF. However, in both HF phenotypes neither MCT nor HIIT induced significant changes in serum levels of NO metabolites when compared to patients randomized to CG.

(085) Montelukast, a LRRC8A Inhibitor Decreases the Contractile Response to Phenylephrine in the Corpus Cavernosum of Diabetic Mice

Abstract Introduction Increased reactive oxygen species are often correlated with erectile dysfunction (ED) by enhancing contractility and favoring the flaccid state of the penis (which is mainly mediated by α-adrenergic innervation) and decreasing the relaxation of the corpus cavernosum (CC) associated with decreased nitric oxide (NO) bioavailability. Leucine Rich Repeat Containing 8 (LRRC8) Volume Regulated Anion Channels (VRACs) regulates Nox1 and modulates the extracellular production of superoxide anion (O2•-). Downregulation of LRRC8 is associated with decreased production of O2•- and we have demonstrated improved relaxation and reduced contraction of the pudendal artery in LRRC8A knockout mice. Objective In this study, we aim to test the hypothesis that inhibition of Nox or LRRC8A decreases phenylephrine (PE)-induced contraction in the CC of diabetic mice. Methods To test this hypothesis, the CC of diabetic (dbdb-/-, 16-week-old) mice were mounted in myographs, and the contraction elicited by PE was performed in the absence and repeated in the presence of the LRRC8 inhibitor, montelukast or Nox1/Nox4 inhibitor, GKT137831. The maximal contraction in the absence of the inhibitor was taken as 100%, and the contraction in the presence of the inhibitor was calculated as a percentage of the maximal contraction attained in the absence of the inhibitor. Results Contraction induced by phenylephrine in the CC of diabetic mice (1.27 + 0.2 mN) was similar to that observed in the control mice (1.26 + 0.4 mN). In the presence of the LRRC8 inhibitor, montelukast, PE-induced contraction of the CC was significantly reduced, reaching maximal contraction of 69 + 7% and 65 + 10% in the control and diabetic group, respectively. In the presence of the Nox1/Nox4 inhibitor, GKT137831, the contraction elicited by PE was reduced only in the diabetic group (68 + 9% of the maximal contraction), whereas in the control group this reduction was not significant (82 + 14% of the maximal contraction). Conclusions This is the first study demonstrating that, in the CC, LRRC8 modulates the contractile response induced by α-adrenergic stimulation and this may be associated with O2•- production, which plays a role in the development of ED. Since a great number of diabetic patients are not benefited by phosphodiesterase 5 inhibitors therapy, LRRC8 might be a potential therapeutic target for the development of new drugs to improve sexual function in diabetes. Disclosure No

Ginsentide TP1 Protects Hypoxia-Induced Dysfunction and ER Stress-Linked Apoptosis.

Hypoxia-induced vascular endothelial dysfunction (VED) is a significant contributor to several severe human diseases, including heart disease, stroke, dementia, and cancer. However, current treatment options for VED are limited due to the lack of understanding of the underlying disease mechanisms and therapeutic leads. We recently discovered a heat-stable microprotein in ginseng, called ginsentide TP1, that has been shown to reduce vascular dysfunction in cardiovascular disease models. In this study, we use a combination of functional assays and quantitative pulsed SILAC proteomics to identify new proteins synthesized in hypoxia and to show that ginsentide TP1 provides protection for human endothelial cells against hypoxia and ER stress. Consistent with the reported findings, we also found that hypoxia activates various pathways related to endothelium activation and monocyte adhesion, which in turn, impairs nitric oxide (NO) synthase activity, reduces the bioavailability of NO, and increases the production of reactive oxygen species that contribute to VED. Additionally, hypoxia triggers endoplasmic reticulum stress and initiates apoptotic signaling pathways associated with cardiovascular pathology. Treatment with ginsentide TP1 reduced surface adhesion molecule expression, prevented activation of the endothelium and leukocyte adhesion, restored protein hemostasis, and reduced ER stress to protect against hypoxia-induced cell death. Ginsentide TP1 also restored NO signaling and bioavailability, reduced oxidative stress, and protected endothelial cells from endothelium dysfunction. In conclusion, this study shows that the molecular pathogenesis of VED induced by hypoxia can be mitigated by treatment with ginsentide TP1, which could be one of the key bioactive compounds responsible for the "cure-all" effect of ginseng. This research may lead to the development of new therapies for cardiovascular disorders.

Sphingolipid Levels and Signaling via Resveratrol and Antioxidant Actions in Cardiometabolic Risk and Disease.

Resveratrol (RSV) is a phenolic compound with strong antioxidant activity, which is generally associated with the beneficial effects of wine on human health. All resveratrol-mediated benefits exerted on different systems and pathophysiological conditions are possible through resveratrol's interactions with different biological targets, along with its involvement in several key cellular pathways affecting cardiometabolic (CM) health. With regard to its role in oxidative stress, RSV exerts its antioxidant activity not only as a free radical scavenger but also by increasing the activity of antioxidant enzymes and regulating redox genes, nitric oxide bioavailability and mitochondrial function. Moreover, several studies have demonstrated that some RSV effects are mediated by changes in sphingolipids, a class of biolipids involved in a number of cellular functions (e.g., apoptosis, cell proliferation, oxidative stress and inflammation) that have attracted interest as emerging critical determinants of CM risk and disease. Accordingly, this review aimed to discuss the available data regarding the effects of RSV on sphingolipid metabolism and signaling in CM risk and disease, focusing on oxidative stress/inflammatory-related aspects, and the clinical implications of this relationship.

Impacts of High Fructose Diet and Chronic Exercise on Nitric Oxide Synthase and Oxidative Stress in Rat Kidney.

Chronic exercise (Ex) exerts antihypertensive and renoprotective effects in rats fed a high fructose diet (HFr). To elucidate the mechanisms, the impacts of an HFr and Ex on the nitric oxide (NO) system and oxidative stress in the kidney were examined. Rats were fed a control diet or an HFr, and a part of the HFr-fed rats underwent treadmill running for 12 weeks. The HFr did not affect nitrate/nitrite (NOx) levels in plasma and urine, and Ex increased the NOx levels. The HFr increased thiobarbituric acid reactive substance (TBARS) levels in plasma and urine, and Ex decreased the HFr-increased TBARS levels in plasma. The HFr increased the neuronal and endothelial NO synthase (nNOS and eNOS) expressions, and Ex enhanced the HFr-increased eNOS expression. The HFr inhibited the eNOS phosphorylation at serine 1177, and Ex restored the HFr-inhibited eNOS phosphorylation. The HFr increased xanthine oxidase and NADPH oxidase activities, and Ex restored the HFr-increased xanthine oxidase activity but enhanced the HFr-increased NADPH oxidase activity. The HFr increased the nitrotyrosine levels, and Ex attenuated the HFr-increased levels. These results indicate that although Ex enhances the HFr-increased eNOS expression and NADPH oxidase activity, an HFr inhibits renal eNOS phosphorylation and NO bioavailability, whereas Ex ameliorates them.

Elderberry extract improves molecular markers of endothelial dysfunction linked to atherosclerosis.

Endothelial dysfunction (ED), secondary to diminished nitric oxide (NO) production and oxidative stress, is an early subclinical marker of atherosclerosis. Reduced NO bioavailability enhances the adhesion of monocytes to endothelial cells and promotes atherosclerosis. Elderberry extract (EB) is known to contain high levels of anthocyanins which could exert vascular protective effects. Specifically, we investigated the functional capacity of EB on various markers of ED. Human umbilical vein endothelial cells (HUVEC) were pretreated with EB 50 μg/mL and stimulated with TNF-α 10 ng/mL. Cell viability, apoptosis, oxidative stress; eNOS, Akt, Nrf2, NOX-4, and NF-κB at the protein level were measured. A co-culture model was used to determine whether EB could prevent the adhesion of monocytes (THP-1) to HUVECs. Moreover, the expression of adhesion molecules and pro-inflammatory cytokines were also measured. It wasdemonstrated that EB prevented TNF-α induced apoptosis and reactive oxygen species production in HUVECs. Additionally, EB upregulated Akt and eNOS activity, and Nrf2 expression in response to TNF-α, whereas it decreased NOX-4 expression and NF-κB activity. EB prevented the adhesion of monocytes to HUVECs, as well as reduced IL-6 and MCP-1 levels, which was associated with inhibition of VCAM-1 expression. Our results demonstrate that EB upregulates key cellular markers of endothelial function and ameliorates markers of ED. EB could be used as a potential nutritional aid for preventing atherosclerosis progression.

Sex-Dependent Impairment of Endothelium-Dependent Relaxation in Aorta of Mice with Overexpression of Hyaluronan in Tunica Media.

Diabetic macroangiopathy is characterized by increased extracellular matrix deposition, including excessive hyaluronan accumulation, vessel thickening and stiffness, and endothelial dysfunction in large arteries. We hypothesized that the overexpression of hyaluronan in the tunica media also led to endothelial cell (EC) dysfunction. To address this hypothesis, we investigated the following in the aortas of mice with excessive hyaluronan accumulation in the tunica media (HAS-2) and wild-type mice: EC dysfunction via myograph studies, nitric oxide (NO) bioavailability via diaminofluorescence, superoxide formation via dihydroethidium fluorescence, and the distances between ECs via stereological methods. EC dysfunction, characterized by blunted relaxations in response to acetylcholine and decreased NO bioavailability, was found in the aortas of male HAS-2 mice, while it was unaltered in the aortas of female HAS-2 mice. Superoxide levels increased and extracellular superoxide dismutase (ecSOD) expression decreased in the aortas of male and female HAS-2 mice. The EC-EC distances and LDL receptor expression were markedly increased in the HAS-2 aortas of male mice. Our findings suggest hyaluronan increases oxidative stress in the vascular wall and that together with increased EC distance, it is associated with a sex-specific decrease in NO levels and endothelial dysfunction in the aorta of male HAS-2 transgenic mice.

Cerebrospinal fluid biomarkers provide evidence for kidney-brain axis involvement in cerebral malaria pathogenesis.

Cerebral malaria is one of the most severe manifestations of malaria and is a leading cause of acquired neurodisability in African children. Recent studies suggest acute kidney injury (AKI) is a risk factor for brain injury in cerebral malaria. The present study evaluates potential mechanisms of brain injury in cerebral malaria by evaluating changes in cerebrospinal fluid measures of brain injury with respect to severe malaria complications. Specifically, we attempt to delineate mechanisms of injury focusing on blood-brain-barrier integrity and acute metabolic changes that may underlie kidney-brain crosstalk in severe malaria. We evaluated 30 cerebrospinal fluid (CSF) markers of inflammation, oxidative stress, and brain injury in 168 Ugandan children aged 18 months to 12 years hospitalized with cerebral malaria. Eligible children were infected with Plasmodium falciparum and had unexplained coma. Acute kidney injury (AKI) on admission was defined using the Kidney Disease: Improving Global Outcomes criteria. We further evaluated blood-brain-barrier integrity and malaria retinopathy, and electrolyte and metabolic complications in serum. The mean age of children was 3.8 years (SD, 1.9) and 40.5% were female. The prevalence of AKI was 46.3% and multi-organ dysfunction was common with 76.2% of children having at least one organ system affected in addition to coma. AKI and elevated blood urea nitrogen, but not other measures of disease severity (severe coma, seizures, jaundice, acidosis), were associated with increases in CSF markers of impaired blood-brain-barrier function, neuronal injury (neuron-specific enolase, tau), excitatory neurotransmission (kynurenine), as well as altered nitric oxide bioavailability and oxidative stress (p < 0.05 after adjustment for multiple testing). Further evaluation of potential mechanisms suggested that AKI may mediate or be associated with CSF changes through blood-brain-barrier disruption (p = 0.0014), ischemic injury seen by indirect ophthalmoscopy (p < 0.05), altered osmolality (p = 0.0006) and through alterations in the amino acids transported into the brain. In children with cerebral malaria, there is evidence of kidney-brain injury with multiple potential pathways identified. These changes were specific to the kidney and not observed in the context of other clinical complications.