[Moxibustion of 45 ℃ at "Zusanli" (ST36) improves vascular endothelial oxidative stress in hyperlipidemia rats].

OBJECTIVE: To explore the antioxidant effect of moxibustion on vascular endothelial function and the under-lying mechanism. METHODS: Forty male SD rats were randomly divided into blank, model, moxibustion and endothelial nitric oxide synthase (eNOS) inhibitor groups, with 10 rats in each group. Hyperlipidemia rat model was established by high fat diet for 8 weeks. Rats in the moxibustion group received 45 ℃ moxibustion at "Zusanli" (ST36) for 10 min once daily for consecutive 4 weeks. Rats in the eNOS inhibitor group received intraperitoneal injection of eNOS inhibitor L-NAME (1 mg/100 g) at the same time of moxibustion intervention. The morphology of abdominal aorta endothelium was observed by HE staining. Lipid deposition in abdominal aorta was observed by oil red O staining. The contents of total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) in serum and reactive oxygen species (ROS), nitric oxide (NO), superoxide dismutase (SOD), oxidized LDL lipoprotein (ox-LDL), endothelin-1 (ET-1), eNOS, malondialdehyde (MDA) in serum and abdominal aorta were determined by ELISA. The expression of eNOS in abdominal aorta was detected by immunofluorescence. RESULTS: HE staining of the abdominal aorta showed no significant pathological abnormality in the blank group; the endovascular cortex was rough, and the inner, media and outer membrane were rough in the model group; the nucleus and surrounding tissue structure were clear and the vascular wall was smooth in the moxibustion group; abdominal aorta texture was rough in the eNOS inhibitor group. Compared with the blank group, the area of oil red O staining in abdominal aorta increased (P<0.05); the contents of serum TC, TG and LDL-C increased (P<0.01, P<0.05) while HDL-C decreased (P<0.05); the contents of ET-1 in serum and abdominal aorta were increased (P<0.01, P<0.05) while the contents of NO and eNOS were decreased (P<0.05, P<0.001); the contents of ROS, ox-LDL and MDA in serum and abdominal aorta were increased (P<0.001, P<0.01, P<0.000 1) while the content of SOD in abdominal aorta was decreased (P<0.000 1); the expression level of eNOS in abdominal aorta was decreased (P<0.05) in the model group. Compared with the model group, the area of oil red O staining in abdominal aorta decreased (P<0.05); the contents of TC, TG and LDL-C in serum decreased (P<0.05) while HDL-C increased (P<0.05); the contents of ET-1 in serum and abdominal aorta were decreased (P<0.01, P<0.05) while the contents of NO and eNOS in abdominal aorta were increased (P<0.001, P<0.01); the contents of ROS and MDA in serum and abdominal aorta were decreased (P<0.001, P<0.01, P<0.05), the content of ox-LDL was decreased (P<0.01) and the content of SOD was increased (P<0.000 1) in abdominal aorta; the expression level of eNOS in abdominal aorta was increased (P<0.05) in the moxibustion group. Compared with the moxibustion group, the contents of serum TC, LDL-C and MDA in the eNOS inhibitor group were increased (P<0.05); the contents of ET-1, ROS, ox-LDL and MDA in abdominal aorta were increased (P<0.05), the contents of NO, eNOS and SOD were decreased (P<0.05); the expression level of eNOS in abdominal aorta was decreased (P<0.05). CONCLUSION: 45 ℃ moxibustion at ST36 can protect and repair vascular endothelial injury in abdominal aorta of hyperlipidemia rats and improve the oxidative stress of vascular endothelium.

Comparison of Three Species of Rhubarb in Inhibiting Vascular Endothelial Injury via Regulation of PI3K/AKT/NF-κB Signaling Pathway.

Background/Aim: Rhubarb, a traditional Chinese medicine derived from three species, is commonly used in the prescriptions for promoting blood circulation and removing blood stasis based on its traditional effects of removing blood stasis and dredging the meridians. It has been reported that rhubarb can protect blood vessels by reducing inflammation and inhibiting vascular endothelial injury (VEI), but the effective components and mechanism of rhubarb inhibiting VEI are still unclear. This study aimed to compare the differences in chemical compositions of the three species of rhubarb and their inhibitory effect on VEI, so as to explain the material basis and select the dominant species to inhibit VEI, and to elucidate the mechanism of rhubarb's inhibitory effect on VEI. Methods: Plant metabolomics was used to compare the chemical components of three species of rhubarb. The efficacy of three species of rhubarb in inhibiting VEI was compared through cell experiments in vitro. At the same time, combined with network pharmacology and molecular docking, the effective components and pathways of rhubarb involved in inhibiting VEI were screened. The mechanism of rhubarb inhibiting VEI was verified by molecular biology. Results: There were significant differences in the distribution of chemical components among the three species of rhubarb. We identified 36 different chemical components in the positive ion mode and 38 different chemical components in the negative ion mode. Subsequently, the results showed significant differences in inhibiting VEI among the three species of rhubarb based on the contents of inflammatory factors (such as IL-1ß, IL-6, and TNF-α), ROS, and NO and confirmed that R. tanguticum had the best inhibitory effect on VEI in the light of the comprehensive efficacy, compared with R. palmatum and R. officinale. Three species of rhubarb alleviated the inflammatory response in LPS-induced EA.hy926 cells by reducing the contents of inflammatory cytokines IL-6, IL-1ß, and TNF-α and decreasing expressions of PI3K, AKT, NF-κB p65, and STAT3 protein in the PI3K/AKT/NF-κB pathway and the inhibition of proteins phosphorylation. In addition, three species of rhubarb could lessen the contents of ROS and NO in EA.hy926 cells induced by LPS. All results indicated that the process of inflammation-induced cellular oxidative stress, which resulted in VEI, was obviously improved by three species of rhubarb. Conclusion: R. tanguticum was more effective among three species of rhubarb, and it had been proved that gallic acid, gallic-acid-O-galloyl-glucoside, procyanidin B-2,3,3'-di-O-gallatein, and other potential components could reduce the contents of inflammatory factors (such as IL-1ß, IL-6, and TNF-α), ROS, and NO by inhibiting the PI3K/AKT/NF-κB signaling pathway and protected the vascular endothelium and the blood vessels by improving the inflammation and oxidative stress reaction.

Large-leaf yellow tea attenuates high glucose-induced vascular endothelial cell injury by up-regulating autophagy and down-regulating oxidative stress.

Vascular endothelial cell injury induced by high glucose (HG) plays an important role in the occurrence and development of diabetic vascular complications. Yellow tea has a protective effect on vascular endothelial cells. However, the molecular mechanisms underlying this effect are unclear. In this study, the effects of the n-butanol fraction of Huoshan large-leaf yellow tea extract (HLYTBE) on vascular endothelial injury were investigated using human umbilical vein endothelial cells (HUVECs) and diabetic mice. In HUVECs, HLYTBE significantly reduced the production of reactive oxygen species, increased the activity of anti-oxidases (superoxide dismutase and glutathione peroxidase), enhanced the production of reduced glutathione, and decreased the level of oxidized glutathione, thereby improving cell viability. HLYTBE also promoted autophagosome formation, increased the LC3-II/LC3-I ratio, increased the expressions of Beclin1 and Atg 5, and decreased the expression of p62. HLYTBE up-regulated p-AMPK and down regulated p-mTOR, and these effects were reversed by compound C, an AMPK inhibitor. HLYTBE reduced apoptosis and cytochrome C expression, and these effects were attenuated by the autophagy inhibitor 3-methyladenine. In vivo studies showed that HLYTBE improved the impaired pyruvate tolerance, glucose tolerance, and insulin resistance; reduced the concentrations of blood glucose, glycated serum protein, lipids, and 8-isomeric prostaglandin 2α; increased the anti-oxidase activity in serum; and alleviated pathological damage in the thoracic aorta of diabetic mice induced by high sucrose-high fat diet along with streptozotocin. The results suggest that HLYTBE protects the vascular endothelium by up-regulating autophagy via the AMPK/mTOR pathway and inhibiting oxidative stress.

Research progress on the mechanism of aging of vascular endothelial cells and the intervention of traditional Chinese medicine: A review.

Vascular senescence is the basic factor of many cardiovascular diseases. Vascular endothelium, as a protective barrier between blood and vascular wall, plays an important role in maintaining the integrity and homeostasis of vascular system. Endothelial cell senescence is an important pathological change of vascular senescence. In recent years, more and more studies have been conducted on vascular endothelial cell senescence, especially on its mechanism. Many research results showed that the mechanism is various, but the systematic elucidation still lacks. Western medicine has little choice in the prevention and treatment of endothelial cell senescence, and the control effect is also limited, while Chinese medicine makes up for the deficiency in this regard. The main mechanisms of vascular endothelial cell aging and the related research progress of traditional Chinese medicine in the prevention and treatment of vascular endothelial aging in recent years were summarized in this paper to provide reference for the research of traditional Chinese medicine in anti-vascular aging and the prevention and treatment of cardiovascular disease.

Endothelial SIRT1 as a Target for the Prevention of Arterial Aging: Promises and Challenges.

ABSTRACT: SIRT1, a member of the sirtuin family of longevity regulators, possesses potent activities preventing vascular aging. The expression and function of SIRT1 in endothelial cells are downregulated with age, in turn causing early vascular aging and predisposing various vascular abnormalities. Overexpression of SIRT1 in the vascular endothelium prevents aging-associated endothelial dysfunction and senescence, thus the development of hypertension and atherosclerosis. Numerous efforts have been directed to increase SIRT1 signaling as a potential strategy for different aging-associated diseases. However, the complex mechanisms underlying the regulation of SIRT1 have posed a significant challenge toward the design of specific and effective therapeutics. This review aimed to provide a summary on the regulation and function of SIRT1 in the vascular endothelium and to discuss the different approaches targeting this molecule for the prevention and treatment of age-related cardiovascular and cerebrovascular diseases.

Endothelial Yin Yang 1 Phosphorylation at S118 Induces Atherosclerosis Under Flow.

RATIONALE: Disturbed flow occurring in arterial branches and curvatures induces vascular endothelial cell (EC) dysfunction and atherosclerosis. We postulated that disturbed flow plays important role in modulating phosphoprotein expression profiles to regulate endothelial functions and atherogenesis. OBJECTIVE: The goal of this study is to discover novel site-specific phosphorylation alterations induced by disturbed flow in ECs to contribute to atherosclerosis. METHODS AND RESULTS: Quantitative phosphoproteomics analysis of ECs exposed to disturbed flow with low and oscillatory shear stress (0.5±4 dynes/cm2) versus pulsatile shear stress (12±4 dynes/cm2) revealed that oscillatory shear stress induces phospho-YY1S118 (serine [S]118 phosphorylation of Yin Yang 1) in ECs. Elevated phospho-YY1S118 level in ECs was further confirmed to be present in the disturbed flow regions in experimental animals and human atherosclerotic arteries. This disturbed flow-induced EC phospho-YY1S118 is mediated by CK2α (casein kinase 2α) through its direct interaction with YY1. Yeast 2-hybrid library screening and in situ proximity ligation assays demonstrate that phospho-YY1S118 directly binds ZKSCAN4 (zinc finger with KRAB [krüppel-associated box] and SCAN [SRE-ZBP, CTfin51, AW-1 and Number 18 cDNA] domains 4) to induce promoter activity and gene expression of HDM2 (human double minute 2), which consequently induces EC proliferation through downregulation of p53 and p21CIP1. Administration of apoE-deficient (ApoE-/-) mice with CK2-specific inhibitor tetrabromocinnamic acid or atorvastatin inhibits atherosclerosis formation through downregulations of EC phospho-YY1S118 and HDM2. Generation of novel transgenic mice bearing EC-specific overexpression of S118-nonphosphorylatable mutant of YY1 in ApoE-/- mice confirms the critical role of phospho-YY1S118 in promoting atherosclerosis through EC HDM2. CONCLUSIONS: Our findings provide new insights into the mechanisms by which disturbed flow induces endothelial phospho-YY1S118 to promote atherosclerosis, thus indicating phospho-YY1S118 as a potential molecular target for atherosclerosis treatment.

Restoration of Vitamin D Levels Improves Endothelial Function and Increases TASK-Like K+ Currents in Pulmonary Arterial Hypertension Associated with Vitamin D Deficiency.

Background: Vitamin D (vitD) deficiency is highly prevalent in patients with pulmonary arterial hypertension (PAH). Moreover, PAH-patients with lower levels of vitD have worse prognosis. We hypothesize that recovering optimal levels of vitD in an animal model of PAH previously depleted of vitD improves the hemodynamics, the endothelial dysfunction and the ionic remodeling. Methods: Male Wistar rats were fed a vitD-free diet for five weeks and then received a single dose of Su5416 (20 mg/Kg) and were exposed to vitD-free diet and chronic hypoxia (10% O2) for three weeks to induce PAH. Following this, vitD deficient rats with PAH were housed in room air and randomly divided into two groups: (a) continued on vitD-free diet or (b) received an oral dose of 100,000 IU/Kg of vitD plus standard diet for three weeks. Hemodynamics, pulmonary vascular remodeling, pulmonary arterial contractility, and K+ currents were analyzed. Results: Recovering optimal levels of vitD improved endothelial function, measured by an increase in the endothelium-dependent vasodilator response to acetylcholine. It also increased the activity of TASK-1 potassium channels. However, vitD supplementation did not reduce pulmonary pressure and did not ameliorate pulmonary vascular remodeling and right ventricle hypertrophy. Conclusions: Altogether, these data suggest that in animals with PAH and severe deficit of vitD, restoring vitD levels to an optimal range partially improves some pathophysiological features of PAH.

Azilsartan ameliorates ox-LDL-induced endothelial dysfunction via promoting the expression of KLF2.

BACKGROUND: Oxidized LDL(Ox-LDL) mediated endothelial dysfunction is involved in the pathogenesis of various cardiovascular diseases, including atherosclerosis. Azilsartan is a potent agent for the treatment of hypertension as the antagonist of the angiotensin II receptor. This study will investigate whether Azilsartan possesses a beneficial effect against endothelial cell dysfunction induced by ox-LDL and explore the underlying preliminary mechanism. METHODS: Ox-LDL was applied to construct an in vitro endothelial dysfunction model in human umbilical vascular endothelial cells (HUVECs). The expression of lectin-type oxidized LDL receptor 1 (LOX-1), endothelial nitric oxide synthase (eNOS), tight junction protein occludin, and transcriptional factor Krüppel-like factor 2 (KLF2) was detected using qRT-PCR and Western blot. ELISA and qRT-PCR were utilized to evaluate the production of chemokine monocyte chemotactic protein 1 (MCP-1) and chemokine (C-X-C motif) Ligand 1 Protein (CXCL1) in treated HUVECs. The generation of nitro oxide (NO) was determined using DAF-FM DA staining assay. KLF2 was silenced by transfecting the cells with specific Small interfering RNA (siRNA). FITC-dextran permeation assay was used to check the endothelial monolayer permeability of treated HUVECs. RESULTS: Firstly, the elevated expressions of LOX-1, MCP-1, and CXCL-1 induced by stimulation with ox-LDL were significantly suppressed by Azilsartan. The downregulated eNOS and reduced production of NO induced by ox-LDL were reversed by the introduction of Azilsartan. Secondly, enlarged endothelial monolayer permeability and decreased expression of occludin stimulated with ox-LDL were greatly reversed by treatment with Azilsartan but were abolished by silencing the expression of KLF2. Lastly, the inhibited expression of KLF2 induced by ox-LDL was significantly elevated by the introduction of Azilsartan. CONCLUSION: Azilsartan might ameliorate ox-LDL-induced endothelial damage via elevating the expression of KLF2.

Arthrospira platensis accelerates the formation of an endothelial cell monolayer and protects against endothelial cell detachment after bacterial contamination.

Within the last years a comprehensive number of scientific studies demonstrated beneficial effect of Arthropira platensis (AP) as dietary supplement due to a high content of proteins, minerals and vitamins. Positive effects like promoting the immune system, reducing inflammation and an anti-oxidant capacity are reported. In this study, the effect of an aqueous AP extract on primary human venous endothelial cells (HUVEC) was investigated. In addition, the effect of AP on HUVEC treated with a bacterial toxin (lipopolysaccharide, LPA), inducing an activation of HUVEC and cellular detachment, was analyzed. Depending on the concentration of AP extract a significantly accelerated formation of an endothelial cell monolayer was observed. Furthermore, the detachment of HUVEC after LPA addition was dramatically reduced by AP. In conclusion, the data are promising and indicatory for an application of Arthrospira platensis in the clinical field.

Hyperglycemic Condition Causes Pro-Inflammatory and Permeability Alterations Associated with Monocyte Recruitment and Deregulated NFκB/PPARγ Pathways on Cerebral Endothelial Cells: Evidence for Polyphenols Uptake and Protective Effect.

Hyperglycemia alters the function of cerebral endothelial cells from the blood-brain barrier, increasing the risk of cerebrovascular complications during diabetes. This study evaluated the protective effect of polyphenols on inflammatory and permeability markers on bEnd3 cerebral endothelial cells exposed to high glucose concentration. Results show that hyperglycemic condition increased nuclear factor kappa B (NFκB) activity, deregulated the expression of interleukin-1 beta (IL-1ß), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), interleukin-10 (IL-10) and endothelial-leukocyte adhesion molecule (E-selectin) genes, raised MCP-1 secretion and elevated monocyte adhesion and transendothelial migration. High glucose decreased occludin, claudin-5, zona occludens-1 (ZO-1) and zona occludens-2 (ZO-2) tight junctions production and altered the endothelial permeability. Characterized polyphenolic extracts from the French medicinal plants Antirhea borbonica, Ayapana triplinervis, Dodonaea viscosa and Terminalia bentzoe, and their major polyphenols quercetin, caffeic, chlorogenic and gallic acids limited the pro-inflammatory and permeability alterations caused by high glucose. Peroxisome proliferator-activated receptor gamma (PPARγ) agonist also attenuated these damages while PPARγ antagonist aggravated them, suggesting PPARγ protective action. Interestingly, polyphenols improved PPARγ gene expression lowered by high glucose. Moreover, polyphenols were detected at the intracellular level or membrane-bound to cells, with evidence for breast cancer resistance protein (BCRP) efflux transporter role. Altogether, these findings emphasize the ability of polyphenols to protect cerebral endothelial cells in hyperglycemic condition and their relevance for pharmacological strategies aiming to limit cerebrovascular disorders in diabetes.

Pyrogallol-Phloroglucinol-6 6-Bieckol on Attenuates High-Fat Diet-Induced Hypertension by Modulating Endothelial-to-Mesenchymal Transition in the Aorta of Mice.

Endothelial-to-mesenchymal transition (EndMT), which is involved in the development of various cardiovascular diseases, is induced by dyslipidemia or obesity. In dyslipidemia, the increased levels of oxidized low-density lipoproteins (oxLDL) upregulated the lectin-type oxidized LDL receptor 1 (Lox-1), which then upregulated the down signaling pathways of PKC-α/MMPs/TGF-ß/SMAD2 or 3 and increased the EndMT. In this study, we investigated the effect of pyrogallol-phloroglucinol-6,6-bieckol (PPB), which is a compound of Ecklonia cava (E. cava), on decreased blood pressure (BP) by attenuating the EndMT in a high-fat diet- (HFD-) fed animal model. We also investigated PPB's attenuation effect on EndMT in oxLDL-treated mouse endothelial cells as an in vitro model. The results indicated that, in the aorta or endothelial cells of mice, the HFD or oxLDL treatment significantly increased the expression of Lox-1/PKC-α/MMP9/TGF-ß/SMAD2/SMAD3. The PPB treatment significantly decreased its expression. In contrast, the HFD or oxLDL treatment significantly decreased the expression of the EC markers (PECAM-1 and vWF) while the PPB treatment significantly increased them. Moreover, the HFD or oxLDL treatment significantly increased the expression of the mesenchymal cell markers (α-SMA and vimentin) while PPB treatment significantly decreased them. PPB decreased the intima-media thickness and extracellular matrix amount of the aorta and attenuated the BP, which was increased by the HFD. In conclusion, PPB attenuated the upregulation of Lox-1/PKC-α/MMP9/TGF-ß/SMAD2 and 3 and restored the EndMT in HFD-fed animals. Moreover, PPB showed a restoring effect on HFD-induced hypertension.

Curcumin Mitigates Hypertension, Endothelial Dysfunction and Oxidative Stress in Rats with Chronic Exposure to Lead and Cadmium.

Lead (Pb) and cadmium (Cd) are environmental pollutants and nonessential elements in the body. Both metals induce the development of hypertension which is associated with oxidative stress. Curcumin (CUR) is a polyphenolic compound with strong antioxidant activity. The present study evaluated the effect of CUR on oxidative stress, alteration of vascular responsiveness and hypertension induced by exposure to either Pb, Cd or the combination of Pb and Cd. Male Sprague-Dawley rats were exposed to low level of lead acetate (100 mg/L) and/or cadmium chloride (10 mg/L) in the drinking water for 16 weeks. The control animals received deionized water as drinking water. CUR (100 mg/kg) or propylene glycol as vehicle was intragastrically administered once daily for the last 4 weeks. Exposure to Pb, Cd or the combination induced increases in blood pressure and peripheral vascular resistance, and decreased the blood pressure response to intravenous infusion to acetylcholine. Supplementation with CUR significantly reduced blood pressure, alleviated oxidative stress, and increased plasma nitrate/nitrite and glutathione in the blood. The effects of CUR were associated with the improvement of vascular responsiveness, upregulation of the endothelial nitric oxide synthase and downregulation of the NADPH oxidase expression. Furthermore, CUR reduced the metal levels in blood, aorta, liver and kidney. Altogether, exposure to the combination of Pb and Cd aggravated hypertension and oxidative stress, and CUR effectively ameliorated these adverse events in metal exposed animals. Data indicate that CUR may be useful as a dietary supplement for protection against the noxious effects of the heavy metals.

Effects of a dammarane-type saponin, ginsenoside Rd, in nicotine-induced vascular endothelial injury.

BACKGROUND: Panax notoginseng (Burk.) F.H. Chen is a traditional medicinal plant widely used to prevent and treat cardiovascular diseases. Ginsenoside Rd (GRd) is a major bioactive component of P. notoginseng, but specific effects on cardiovascular disease-related pathogenic processes are rarely studied, especially vascular endothelial injury. PURPOSE: This study investigated the potential protective efficacy of GRd against nicotine-induced vascular endothelial cell injury, disruption of vascular nitric oxide (NO) signaling, aberrant endothelium-monocyte adhesion, platelet aggregation, and vasoconstriction. STUDY DESIGN/METHODS: Vascular endothelial injury and functional disruption were investigated in cultured human umbilical vein endothelial cells (HUVECs) by biochemical assays for nitric oxide (NO) and angiotensin II (Ang II), immunofluorescence (IF) and western blotting for expression analyses of apoptosis- related proteins, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), Ang II type receptor 1 (AGTR1), toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor-kappa B (NF-κB). In addition, vascular protection by GRd was examined in nicotine-administered Sprague-Dawley (SD) rats by serum NO and Ang II assays, and by hematoxylin-eosin (HE) and immunostaining of aorta. We also examined effects of GRd on monocyte (THP-1 cells) adhesion assays, adenosine diphosphate (ADP)-induced platelet aggregation, and phenylephrine (PE)-induced vasoconstriction of isolated rat aortic rings. RESULTS: In HUVECs, nicotine significantly suppressed NO production, enhanced Ang II production, downregulated eNOS expression, and upregulated expression levels of AGTR1, TLR4, MyD88, NF-κB, iNOS, Bax/Bcl-2 ratio, cleaved caspase-3, and cytochrome c (cyt c). All of these changes were significantly reversed by GRd. In rats, oral GRd reversed the reduction NO and enhanced Ang II production in serum induced by nicotine administration, and HE staining revealed protection of aortic endothelial cells. In addition, GRd reversed nicotine-mediated enhancement of HUVECs-monocyte adhesion, inhibited ADP-induced platelet aggregation and PE-induced vasoconstriction. CONCLUSION: GRd may prevent nicotine-induced cardiovascular diseases by preserving normal vascular endothelial NO signaling, suppressing platelet aggregation and vasoconstriction, and by preventing endothelial cell-monocyte adhesion.

Cigarette Smoke Extract and Its Cytotoxic Factor Acrolein Inhibit Nitric Oxide Production in Human Vascular Endothelial Cells.

Acrolein (ACR), a highly reactive α,ß-unsaturated aldehyde, is a major cytotoxic factor in nicotine- and tar-free cigarette smoke extract (CSE). There are conflicting results regarding endothelial functions despite the fact that both CSE and ACR cause cellular damage. Several lines of evidence indicate that CSE impairs endothelium-derived nitric oxide (NO)-dependent vasodilation by reducing the activity and protein expression of endothelial NO synthase (eNOS), whereas ACR elicits endothelium-dependent vasorelaxation by increasing the production of NO and expression of eNOS. To clarify whether CSE and its cytotoxic factor ACR cause endothelial dysfunction, this study examined the effects of CSE and ACR on human vascular endothelial EA.hy926 cells. CSE and ACR reduced the phosphorylation of eNOS at serine (Ser)1177 and total expression of eNOS. The CSE- and ACR-induced decrease in the phosphorylation and expression of eNOS was counteracted by glutathione (reduced form), an antioxidant. Basal NO production was inhibited by CSE, ACR, NG-nitro-L-arginine methyl ester (a competitive eNOS inhibitor), and nominally Ca2+-free solution supplemented with BAPTA-AM (a membrane permeable Ca2+ chelator). These results indicate that CSE and ACR increase oxidative stress, and reduce NO production by reducing the activity and total protein level of eNOS.

Modulatory properties of cardiac and quercetin glycosides from Dacryodes edulis seeds during L-NAME-induced vascular perturbation.

Background Numerous food wastes have been identified to possess potent bioactive compounds used for the treatment of several diseases. Therefore this study evaluated the potentials of cardiac and quercetin glycosides extracted from Dacryodes edulis seeds to reverse vascular and endothelial damage (VAED). Methods The glycoside composition of the seeds was extracted using standard methods and characterized by gas chromatography. We then recruited rats with L-NAME-induced VAED based on confirmatory biomarkers cardiac troponin (CnT), cellular adhesion molecule (VCAM-1), lipoprotein associated phospholipase A2 (Lp-PLA2), RAAS, VWF, endothelin, eNOx, and homocysteine. Only rats that showed total alterations of all biomarkers were recruited into the respective experimental groups and treated with either metaprolol succinate (met.su) + losartan or glycoside extracts of D. edulis seeds (NPSG). Results Chromatographic isolation of glycosides in the seed showed predominance of artemetin (1.59 mg/100 g), amygdalin (3.68 mg/100 g), digitoxin (19.21 mg/100 g), digoxin (27.23 mg/100 g), avicularin (133.59 mg/100 g), and hyperoside (481.76 mg/100 g). We observed decreased water intake and higher heart beats under vascular damage as the experiment progressed up to the fourth week. The met.su + losartan and H.D NPSG proved effective in restoring troponin, but both doses of NPSG normalized the VCAM-1 and RAAS activities excluding aldosterone and Lp-PLA2. Among the endothelial dysfunction biomarkers, H.D NPSG produced equivalent effects to met.su + losartan towards restoring the eNOx and VWF activities, but showed higher potency in normalizing the endothelin and Hcy levels. Conclusions We thus propose that the synergistic effect of the isolated glycosides from D. edulis shown in our study proved potent enough at high doses in treatment of vascular and endothelial dysfunction.

Dietary nitrate attenuated endothelial dysfunction and atherosclerosis in apolipoprotein E knockout mice fed a high-fat diet: A critical role for NADPH oxidase.

Nitric oxide (NO) deficiency and NADPH oxidase plays key roles in endothelial dysfunction and atherosclerotic plaque formation. Recent evidence demonstrates that nitrate-nitrite-NO pathway in vivo exerts beneficial effects upon the cardiovascular system. We aimed to investigate the effects of dietary nitrate on endothelial function and atherosclerosis in apolipoprotein E knockout (ApoE-/-) mice fed a high-fat diet. It was shown that dietary nitrate significantly attenuated aortic endothelial dysfunction and atherosclerosis in ApoE-/- mice. Mechanistic studies revealed that dietary nitrate significantly improved plasma nitrate/nitrite, inhibited vascular NADPH oxidase activity and oxidative stress in ApoE-/- mice, while xanthine oxidoreductase (XOR) expression and activity was enhanced in ApoE-/- mice in comparison with wide type animals. These beneficial effects of nitrate in ApoE-/- mice were abolished by PTIO (NO scavenger) and significantly prevented by febuxostat (XOR inhibitor). In the presence of nitrate, no further effect of apocynin (NADPH oxidase inhibitor) was observed, suggesting NADPH oxidase as a possible target. In vitro, NO donor significantly inhibited NADPH oxidase activity in vascular endothelial cells via the induction of heme oxygenase-1. Altogether, boosting this nitrate-nitrite-NO signaling pathway resulted in the decreases of vascular NADPH oxidase-derived oxidative stress and endothelial dysfunction, and consequently protected ApoE-/- mice against atherosclerosis. These findings may have novel nutritional implications for the preventive and therapeutic strategies against vascular endothelial dysfunction in atherosclerotic disease.

The protective effects of walnut green husk polysaccharide on liver injury, vascular endothelial dysfunction and disorder of gut microbiota in high fructose-induced mice.

This study aimed to investigate the protective effects of walnut green husk polysaccharide (WGHP) on liver injury, vascular endothelial dysfunction and disorder of gut microbiota in mice induced by high fructose (HF) diet. The chemical analysis results show that the walnut green husk polysaccharide is a low molecular weight acidic heteropolysaccharide, composed mainly of glucuronic acid, arabinose and galactose. Biochemical analysis showed that WGHP significantly improved glucose metabolism and lipid metabolism and decreased oxidative stress in HF-diet induced obesity mice. Histopathological observation of liver and cardiovascular aorta confirmed the protective effects of WGHP on hepatic steatosis and vascular endothelial dysfunction. Furthermore, 16S rRNA sequencing results demonstrated that WGHP reversed the disorders of gut microbiota caused by HF, decreased the relative abundance of Verrucomicrobia and increased the relative abundance of Deferribacteres at the phylum level, decreased the relative abundance of Akkermansia, Lachnoclostridium and norank_f__Muribaculaceae and increased the relative abundance of Prevotellaceae_UCG-001, Helicobacter, Alloprevotella and Allobaculum at the genus levels. Our results indicate that WGHP may act as a functional polysaccharide for protecting liver and cardiovascular in HF-fed mice.

Extracts of Thai Perilla frutescens nutlets attenuate tumour necrosis factor-α-activated generation of microparticles, ICAM-1 and IL-6 in human endothelial cells.

Elevation of endothelial microparticles (EMPs) play an important role in the progression of inflammation-related vascular diseases such as cardiovascular diseases (CVDs). Thai perilla (Perilla frutescens) nutlets are rich in phenolic compounds and flavonoids that exert potent antioxidant and anti-inflammatory effects. We found that the ethyl acetate (EA) and ethanol (Eth) extracts of Thai perilla nutlets contain phenolic compounds such as luteolin, apigenin, chryseoriol and their glycosides, which exhibit antioxidant activity. The goal of the present study was to investigate the effects of the extracts on endothelial activation and EMPs generation in tumour necrosis factor-α (TNF-α)-induced EA.hy926 cells. We found that TNF-α (10 ng/ml) activated EA.hy926 cells and subsequently generated EMPs. Pre-treatment with the extracts significantly attenuated endothelial activation by decreasing the expression of the intracellular adhesion molecule-1 (ICAM-1) in a dose-dependent manner. Only the Eth extract showed protective effects against overproduction of interleukin-6 (IL-6) in the activated cells. Furthermore, the extracts significantly reduced TNF-α-enhanced EMPs generation in a dose-dependent manner. In conclusion, Thai perilla nutlet extracts, especially the Eth extract, may have potential to protect endothelium against vascular inflammation through the inhibition of endothelial activation and the generation of endothelial microparticles (EMPs).

Vascular Effects of Avocado Seed Glycosides during Diabetes-induced Endothelial Damage.

BACKGROUND AND OBJECTIVES: The relationship between vascular damage and diabetes mellitus was exploited using avocado seed extracts. The purpose of the study was to understand the therapeutic relevance of glycosides compared to standard vascular and anti-diabetic drugs. Constituent Avocado Seed Glycosides (ASG) were analysed and administered to rats with Diabetes-Induced Vascular Damage (DIVD). METHODS: The rats were first administered with streptozotocin and screened after seven days for alterations in blood glucose, insulin, vascular cell adhesion molecule (VCAM-1), Von Willebrand factor (VWF), Renin-Angiotensin-Aldosterone System (RAS), eNOx, and endothelin-1 (ET-1). Only rats that satisfied these criteria were recruited and treated with either glibenclamide, met.su + losart, or 200 mg/kg body weight ASG for 28 days. RESULTS: There was an abundance of digitoxin (13.41 mg/100g), digoxin (17.98 mg/100g), avicularin (165.85 mg/100g), and hyperoside (282.51 mg/100g). ASG or met.su + losart exhibited slight modulatory properties on glucose homeostasis. Rats with DIVD showed elevated renin, angiotensin, VCAM-1 and Lp-PLA2 levels but slightly decreased with glibenclamide treatment and normalized with ASG or met.su + losart administration. All treatments normalized Hcy levels. DIVD caused the overproduction of CnT, LDH, Crt-K, LDL-c, TG, and TC and suppressed HDL-c but was completely normalized by the ASG. Water intake remained altered in treated rats. CONCLUSION: The ASG had no relevant effect on glucose homeostasis during DIVD but showed significant vasoprotective properties.

Protective Effect of Epigallocatechin Gallate on Endothelial Disorders in Atherosclerosis.

Healthy vascular endothelial cells regulate vascular tone and permeability, prevent vessel wall inflammation, enhance thromboresistance, and contribute to general vascular health. Furthermore, they perform important functions including the production of vasoactive substances such as nitric oxide (NO) and endothelium-derived hyperpolarizing factors, as well as the regulation of smooth muscle cell functions. Conversely, vascular endothelial dysfunction leads to atherosclerosis, thereby enhancing the risk of stroke, myocardial infarction, and other cardiovascular diseases (CVDs). Observational studies and randomized trials showed that green tea intake was inversely related to CVD risk. Furthermore, evidence indicates that epigallocatechin gallate (EGCG) found in green tea might exert a preventive effect against CVDs. EGCG acts as an antioxidant, inducing NO release and reducing endothelin-1 production in endothelial cells. EGCG enhances the bioavailability of normal NO by reducing levels of the endogenous NO inhibitor asymmetric dimethylarginine. Furthermore, it inhibits the enhanced expression of adhesion molecules such as vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 and attenuates monocyte adhesion. In addition, EGCG prevents enhanced oxidative stress through the Nrf2/HO-1 pathway. These effects indicate that it might prevent the production of reactive oxygen species, inhibit inflammation, and reduce endothelial cell apoptosis during the initial stages of atherosclerosis. The current review summarizes recent research in this area and discusses novel findings regarding the protective effect of EGCG on endothelial dysfunction and CVDs in general.