Aortic Nitric Oxide Research Articles

Vascular injury associated with ethanol intake is driven by AT1 receptor and mitochondrial dysfunction

BackgroundRenin-angiotensin (Ang II)-aldosterone system (RAAS) is crucial for the cardiovascular risk associated with excessive ethanol consumption. Disturbs in mitochondria have been implicated in multiple cardiovascular diseases. However, if mitochondria dysfunction contributes to ethanol-induced vascular dysfunction is still unknown. We investigated whether ethanol leads to vascular dysfunction via RAAS activation, mitochondria dysfunction, and mitochondrial reactive oxygen species (mtROS). MethodsMale C57/BL6J or mt-keima mice (6–8-weeks old) were treated with ethanol (20% vol./vol.) for 12 weeks with or without Losartan (10 mg/kg/day). ResultsEthanol induced aortic hypercontractility in an endothelium-dependent manner. PGC1α (a marker of biogenesis), Mfn2, (an essential protein for mitochondria fusion), as well as Pink-1 and Parkin (markers of mitophagy), were reduced in aortas from ethanol-treated mice. Disturb in mitophagy flux was further confirmed in arteries from mt-keima mice. Additionally, ethanol increased mtROS and reduced SOD2 expression. Strikingly, losartan prevented vascular hypercontractility, mitochondrial dysfunction, mtROS, and restored SOD2 expression. Both MnTMPyP (SOD2 mimetic) and CCCP (a mitochondrial uncoupler) reverted ethanol-induced vascular dysfunction. Moreover, L-NAME (NOS inhibitor) and EUK 134 (superoxide dismutase/catalase mimetic) did not affect vascular response in ethanol group, suggesting that ethanol reduces aortic nitric oxide (NO) and H2O2 bioavailability. These responses were prevented by losartan. ConclusionAT1 receptor modulates ethanol-induced vascular hypercontractility by promoting mitochondrial dysfunction, mtROS, and reduction of NO and H2O2 bioavailability. Our findings shed a new light in our understanding of ethanol-induced vascular toxicity and open perspectives of new therapeutic approaches for patients with disorder associated with abusive ethanol drinking.

Oxidized dietary lipids induce vascular inflammation and atherogenesis in post-menopausal rats: estradiol and selected antihyperlipidemic drugs restore vascular health in vivo

BackgroundThermoxidation of edible oil through deep fat frying results in the generation of several oxidized products that promote lipid peroxidation and ROS production when eaten. Consumption of thermoxidized oil in post-menopausal conditions where the estrogen level is low contributes to cardiovascular disease. This study evaluates the role of estradiol and antihyperlipidemic agents (AHD) in restoring the vascular health of ovariectomized (OVX) rats fed with thermoxidized palm oil (TPO) and thermoxidized soya oil (TSO) diets.MethodA total of 10 groups of rats (n = 6) were set up for the experiment. Group I (normal control) rats were sham handled while other groups were OVX to bring about estrogen deficient post-menopausal state. Group II (OVX only) was not treated and received normal rat chow. Groups III-X were fed with either TPO or TSO diet for 12 weeks and treated with estradiol (ETD) 0.2 mg/kg/day, atorvastatin (ATV) 10 mg/kg/day, and a fixed-dose combination of ezetimibe and ATV (EZE 3 mg/kg/day + ATV 10 mg/kg/day).ResultsPro-atherogenic lipids levels were significantly elevated in untreated TSO and TPO groups compared to OVX and sham, resulting in increased atherogenic and Coronary-risk indices. Treatment with Estradiol and AHDs significantly reduced the total cholesterol, triglycerides, low-density lipoprotein cholesterol as well as AI and CRI compared to untreated TSO and TPO groups, whereas TSO and TPO groups showed significant elevation in these parameters compared to Group I values. Moreover, aortic TNF-α levels were extremely elevated in the untreated TSO and TPO compared to Group I. TNF-α levels were significantly reduced in rats treated with AHDs and ETD. Localized oxidative stress was indicated in the aortic tissues of TSO and TPO-fed OVX rats by increased malondialdehyde and decreased glutathione, catalase, and superoxide dismutase levels. This contributed to a depletion in aortic nitric oxide. AHDs and ETD replenished the nitric oxide levels significantly. Histological evaluation of the aorta of TSO and TPO rats revealed increased peri-adventitia fat, aortic medial hypertrophy, and aortic recanalization. These pathologic changes were less seen in AHDs and ETD rats.ConclusionThis study suggests that ETD and AHDs profoundly attenuate oxidized lipid-induced vascular inflammation and atherogenesis through oxidative-stress reduction and inhibition of TNF-α signaling.

Effect of Carotid Body Denervation on Systemic Endothelial Function in a Diabetic Animal Model.

Endothelial dysfunction is an essential intermediary for development of cardiovascular diseases associated with diabetes and hypertension (HT). The carotid body (CB) dysfunction contributes to dysmetabolic states, and the resection of carotid sinus nerve (CSN) prevents and reverts dysmetabolism and HT. Herein, we investigated if CSN denervation ameliorates systemic endothelial dysfunction in an animal model of type 2 diabetes mellitus (T2DM).We used Wistar male rats submitted to HFHSu diet during 25weeks and the correspondent age-matched controls fed with a standard diet. CSN resection was performed in half of the groups after 14weeks of diet. In vivo insulin sensitivity, glucose tolerance and blood pressure, ex vivo aortic artery contraction and relaxation and nitric oxide (NO) levels in plasma and aorta, aorta nitric oxide synthase (NOS) isoforms, and PGF2αR levels were evaluated.We demonstrated that, alongside to dysmetabolism and HT reversion, CSN resection restores endothelial function in the aorta and decreases the NO levels in plasma and aorta at the same time that restores normal levels of iNOS in aorta without changing eNOS or PGF2αR levels.These results suggest that the modulation of CB activity can be important for the treatment of HT and endothelial dysfunction related with T2DM.

Olive cake reduces blood pressure, oxidative stress, aortic endothelial dysfunction and vascular remodeling, in dexamethasone-induced hypertensive rats

BACKGROUND/AIM: Hypertension is a global public health problem and a leading cause of cardiovascular morbidity and mortality. In this paper, we study the effect of olive cake (OC) on blood pressure, endothelial dysfunction, redox status and vascular remodeling in dexamethasone-induced hypertensive (HT) rats. METHODS: HT rats were divided into two groups fed standard diet supplemented (HT-OC) or not (HT) with OC at 7.5% for 28 days. A control (C) was submitted to standard diet for the same experimental period. RESULTS: Systolic, diastolic and mean blood pressures were higher in the HT vs C and decreased in HT-OC vs HT. Aortic nitric oxide value was decreased in the HT vs the C and increased in HT-OC vs HT. Aortic lipid and protein oxidation products were higher in the HT than C and lower in the HT-OC vs HT. Aortic antioxidant enzymes activities were reduced in HT than control and increased in the HT-OC vs HT. The aortic wall thickness, medial cross-sectional area, media to lumen ratio and the number of VSMCs were higher in the HT and the OC has regressed vascular redemptions. CONCLUSION: In hypertensive rats, OC may alleviate blood pressure and arterial remodeling by suppressing oxidative stress, increasing antioxidant activity, improving endothelial function, preventing smooth muscle proliferation and thickening of the tunica media.

Chronic stress induced perivascular adipose tissue impairment of aortic function and the therapeutic effect of exercise.

What is the central question of this study? Thoracic perivascular adipose tissue (tPVAT) is known to, in part, regulate aortic function: what are the effects of unpredictable chronic mild stress (UCMS) on the tPVAT regulation of aortic function and what is the role of exercise training in alleviating the potential negative actions of UCMS on tPVAT? What is the main finding and its importance? UCMS causes tPVAT to disrupt endothelium-dependent dilatation, increases inflammatory cytokine production and diminishes tPVAT-adiponectin. Exercise training proved efficacious in preventing tPVAT-mediated disruption of aortic function. The data support a tPVAT mechanism through which chronic stress negatively impacts vascular health, which adds to our knowledge of how psychological disorders might increase the risk of cardiovascular disease. Chronic stress is a major risk for cardiovascular disease. Perivascular adipose tissue (PVAT) has been shown to regulate vascular function; however, the impact of chronic stress and the comorbidity of metabolic syndrome (MetS) on thoracic (t)PVAT is unknown. Additionally, aerobic exercise training (AET) is known to combat the pathology of MetS and chronic stress, but the role of tPVAT in these actions is also unknown. Therefore, the purpose of this study was to examine the effects of unpredictable chronic mild stress (UCMS) on the tPVAT regulation of aortic function and the preventative effect of AET. Lean (LZR) and obese (OZR) Zucker rats (16-17weeks old) were exposed to 8weeks of UCMS with and without treadmill exercise (AET). In LZR, UCMS impaired aortic endothelium-dependent dilatation (EDD) (assessed ex vivo by wire myography) and aortic stiffness (assessed by elastic modulus) with no change in OZR subject to UCMS. However, both LZR and OZR UCMS tPVAT impaired EDD compared to respective controls. LZR and OZR subject to UCMS had higher oxidative stress production, diminished adiponectin and impaired aortic nitric oxide levels. Divergently, UCMS induced greater inflammatory cytokine production in LZR UCMS tPVAT, but not in OZR UCMS tPVAT. AET prevented the tPVAT impairment of aortic relaxation with UCMS in LZR and OZR. Additionally, AET reduced aortic stiffness in both LZR and OZR. These beneficial effects on tPVAT regulation of the aorta are likely due to AET preservation of adiponectin, reduced oxidative stress and inflammation, and enhanced nitric oxide. UCMS impaired tPVAT-regulated aortic function in LZR, and augmented MetS-induced EDD in OZR. Conversely, AET in combination with UCMS largely preserved aortic function and the tPVAT environment, in both groups.

Loss of Transforming Growth Factor Beta Signaling in Aortic Smooth Muscle Cells Causes Endothelial Dysfunction and Aortic Hypercontractility.

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Gestational intermittent hypoxia induces endothelial dysfunction, reduces perivascular adiponectin and causes epigenetic changes in adult male offspring.

Obstructive sleep apnoea (OSA) is characterized by intermittent hypoxia, which causes oxidative stress and inflammation and increases the risk of cardiovascular disease. OSA during pregnancy causes adverse maternal and fetal outcomes. The effects of pre-existing OSA in pregnant women on cardiometabolic outcomes in the offspring are unknown. We evaluated basic metabolic parameters, as well as aortic vascular and perivascular adipose tissue (PVAT) function in response to adiponectin, and examined DNA methylation of adiponectin gene promoter in PVAT in 16-week-old adult offspring exposed to gestational intermittent hypoxia (GIH). GIH decreased body weights at week 1 in both male and female offspring, and caused subsequent increases in body weight and food consumption in male offspring only. Adult female offspring had normal levels of lipids, glucose and insulin, with no endothelial dysfunction. Adult male offspring exhibited dyslipidaemia, insulin resistance and hyperleptinaemia. Decreased endothelial-dependent vasodilatation, loss of anti-contractile activity of PVAT and low circulating PVAT adiponectin levels, as well as increased pro-inflammatory gene expression and DNA methylation of adiponectin gene promoter, occurred in adult male offspring. Our results suggest that male offspring of women with OSA could be at risk of developing cardiometabolic disease during adulthood. Perturbations during pregnancy can program the offspring to develop cardiometabolic diseases later in life. Obstructive sleep apnoea (OSA) is a chronic condition that frequently affects pregnancies and leads to adverse fetal outcomes. We assessed the offspring of female mice experiencing gestational intermittent hypoxia (GIH), a hallmark of OSA, for changes in metabolic profiles, aortic nitric oxide (NO)-dependent relaxations, perivascular adipose tissue (PVAT) anti-contractile activities and the responses to adiponectin, and DNA methylation of the adiponectin gene promoter in PVAT tissue. Pregnant mouse dams were exposed to intermittent hypoxic cycles ( 21-12%) for 18 days. GIH resulted in lower body weights of pups at week 1, followed by significant weight gain by week 16 of age in male but not female offspring. Plasma lipids, leptin and insulin resistance were higher in GIH male adult offspring. Endothelium-dependent relaxation in response to ACh and the anti-contractile activity of PVAT in the abdominal aorta was reduced in GIH adult male offspring. Incubation of arteries from GIH adult male offspring with adiponectin restored the anti-contractile activity of PVAT. Both circulating and PVAT tissue homogenate levels of adiponectin, as well as gene expression of adiponectin in PVAT, were lower in GIH male offspring, along with an increased gene expression of inflammatory cytokines. Pyrosequencing of adiponectin gene promoter in PVAT showed increased DNA methylation in GIH male offspring. Our results indicate that GIH leads to vascular disease in adult male offspring through PVAT dysfunction, which was associated with low adiponectin levels and epigenetic modifications on the adiponectin gene promoter.

Cinnamaldehyde protects from methylglyoxal-induced vascular damage: Effect on nitric oxide and advanced glycation end products.

The protective effect and mechanism(s) of action of cinnamaldehyde on the highly reactive secondary sugar derivative, methylglyoxal, induced vascular damage were investigated using isolated rat thoracic aorta. Aorta was incubated with methylglyoxal and cinnamaldehyde where vascular reactivity was assessed through phenylephrine- and acetylcholine-induced contraction and relaxation, respectively. Cinnamaldehyde's antioxidant activity, ability to induce aortic nitric oxide release, and effect on advanced glycation end products formation (AGEs) was also studied. Results showed that cinnamaldehyde significantly alleviated the exaggerated contraction and improved the attenuated dilation of the aorta secondary to incubation with methylglyoxal. Furthermore, cinnamaldehyde stimulated aortic nitric oxide production from isolated aorta giving levels similar to acetylcholine and significantly reduced both methylglyoxal-induced AGEs and protein oxidation products formation. In conclusion, cinnamaldehyde protects from methyglyoxal-induced vascular damage mainly by improving the vasodilation in addition to endothelial nitric oxide production and reducing the detrimental AGE-inflicted vascular damage. PRACTICAL APPLICATIONS: The use of naturally occurring products to alleviate various disease-related complications is highly attractive due to their easy availability, relatively affordable prices compared to pharmaceutical products, and their favorable safety profile. In the case of cinnamaldehyde, its excessive and highly reputable consumption in the food industry facilitates promoting a daily intake of the natural compound with the purpose of counteracting the destructive effect that elevated blood glucose has on vascular function. According to findings obtained from this study, frequent cinnamaldehyde intake will improve vascular reactivity by acting on vasodilatory mechanisms and inhibiting glycation reactions, hence improving the hyperglycemia associated hypertensive state. The study also paves the way for future research to determine the clinical efficacy of cinnamaldehyde having established its competence in protecting vascular function in a lab setting.

Alcohol Consumption in Combination with an Atherogenic Diet Increased Indices of Atherosclerosis in Apolipoprotein E/Low-Density Lipoprotein Receptor Double-Knockout Mice.

Alcohol abuse and adherence to atherogenic diet (AD; a low-carbohydrate-high-protein diet) have been positively associated with cardiovascular disease. In addition, it has been demonstrated clinically that dietary intake is increased on days when alcohol is consumed. Here, the additive effects of ethanol (EtOH) and AD on atherosclerosis, a major underlying cause of cardiovascular disease, were investigated in apolipoprotein E/low-density lipoprotein receptor double-knockout (KO) mice. The mechanisms, especially aortic oxidative stress damage, were highlighted. Twelve-week-old male KO mice on AD with or without EtOH treatment were bred for 4months. Age-matched male C57BL/6J mice on a standard chow diet without EtOH treatment served as controls. Analyses were conducted using ultrasound biomicroscopy, histopathological and fluorescence immunohistochemical examinations, Western blots, and polymerase chain reaction. KO mice on AD with EtOH treatment showed increases in aortic maximum intima media thickness, hypoechoic plaque formation, and mean Oil-Red-O content. These results were associated with enhanced ratio of aortic 8-hydroxy-2'-deoxyguanosine (8-OHdG)-immunopositive area to the metallothionein (MT) immunopositive area and suppression of AD-induced up-regulated aortic Mt1, Mt2, and upstream stimulatory factor 1 mRNA expressions. Moreover, 8-OHdG was expressed in the nuclei of CD31- and alpha smooth muscle actin-immunopositive cells, and the up-regulated mRNA expressions of aortic nitric oxide synthase 3 and platelet-derived growth factors were only observed in the KO mice on AD with EtOH treatment. Alcohol abuse and adherence to AD may promote the shift of aortic oxidative stress and antioxidative stress balance toward oxidative stress predominance and reduced antioxidative stress, which may be partly due to the decrease in MT at the cell biological level and down-regulation of Mt at the gene level, which in turn could play a role in the up-regulation of endothelial dysfunction-related and vascular smooth muscle cell proliferation-related gene expression and the progression of atherosclerosis in mice with hyperlipidemia.

Cinnamaldehyde ameliorates STZ-induced rat diabetes through modulation of IRS1/PI3K/AKT2 pathway and AGEs/RAGE interaction.

Type 2 diabetes mellitus (T2D) is a chronic metabolic disorder considered to be the most predominant form of diabetes throughout the world. This study aimed to investigate the possible effects of cinnamaldehyde (CIN) on insulin signaling pathways in STZ-induced T2D rat model. T2D was originated by feeding rats with a high-fat diet (HFD) plus 25% fructose solution plus streptozotocin (STZ) (35mg/kg, i.p.). CIN effects were investigated on fasting blood glucose, insulin, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), liver biomarkers, lipid profile, oxidative stress biomarkers, serum advanced glycation end products (AGEs) and its receptors (RAGE) in the aorta, and histopathology of the liver and aorta. Additionally, the mRNA expression of hepatic insulin signaling pathway genes, phosphorylated AKT (serine 473) (P-AKT ser473) level, and aortic nitric oxide synthase3 (eNOS) and NADPH oxidase4 (NOX4) were determined. CIN treatment for 30days significantly decreased OGTT, ITT, fasting blood glucose, insulin, and HOMA-IR and increased HOMA-β index when compared to diabetic rats. CIN also improved lipid profile and decreased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, serum AGEs, and aortic RAGE. Additionally, CIN treatment significantly decreased hepatic malondialdehyde (MDA), increased hepatic and aortic glutathione (GSH) and superoxide dismutase (SOD), and decreased steatosis and inflammation observed in liver tissue of rats. Additionally, significant elevation in mRNA expression of insulin receptor substrate1 (IRS1), phosphatidylinositol 3-kinase regulatory subunit1 (PI3K-P85 subunit), and AKT serine/threonine kinase2 (AKT2); increased levels of P-AKT ser473 and aortic eNOS; and decrease in mRNA expression of NOX4 were detected in CIN-treated group when compared to diabetic group. This study suggests antidiabetic and antioxidant effects of CIN probably through upregulation of eNOS and IRS1/PI3K/AKT2 signaling pathway and alleviating AGEs, RAGE, and NOX4 elevation.

Effects of Different Exercise Modes on Arterial Stiffness and Nitric Oxide Synthesis.

Aerobic training (AT) and high-intensity intermittent training (HIIT) reduce arterial stiffness, whereas resistance training (RT) induces deterioration of or no change in arterial stiffness. However, the molecular mechanism of these effects of different exercise modes remains unclear. This study aimed to clarify the difference of different exercise effects on endothelial nitric oxide synthase (eNOS) signaling pathway and arterial stiffness in rats and humans. In the animal study, forty 10-wk-old male Sprague-Dawley rats were randomly divided into four groups: sedentary control (CON), AT (treadmill running, 60 min at 30 m·min, 5 d·wk for 8 wk), RT (ladder climbing, 8-10 sets per day, 3 d·wk for 8 wk), and HIIT (14 repeats of 20-s swimming session with 10-s pause between sessions, 4 d·wk for 6 wk from 12-wk-old) groups (n = 10 in each group). In the human study, we confirmed the effects of 6-wk HIIT and 8-wk AT interventions on central arterial stiffness and plasma nitrite/nitrate level in untrained healthy young men in randomized controlled trial (HIIT, AT, and CON; n = 7 in each group). In the animal study, the effect on aortic pulse wave velocity (PWV), as an index of central arterial stiffness, after HIIT was the same as the decrease in aortic PWV and increase in arterial eNOS/Akt phosphorylation after AT, which was not changed by RT. A negative correlation between aortic PWV and eNOS phosphorylation was observed (r = -0.38, P < 0.05). In the human study, HIIT- and AT-induced changes in carotid-femoral PWV (HIIT -115.3 ± 63.4 and AT -157.7 ± 45.7 vs CON 71.3 ± 61.1 m·s, each P < 0.05) decreased, and plasma nitrite/nitrate level increased compared with those in CON. HIIT may reduce central arterial stiffness via the increase in aortic nitric oxide bioavailability despite it being done in a short time and short term and has the same effects as AT.

Endothelial SHIP2 Suppresses Nox2 NADPH Oxidase-Dependent Vascular Oxidative Stress, Endothelial Dysfunction, and Systemic Insulin Resistance.

Shc homology 2-containing inositol 5' phosphatase-2 (SHIP2) is a lipid phosphatase that inhibits insulin signaling downstream of phosphatidylinositol 3-kinase (PI3K); its role in vascular function is poorly understood. To examine its role in endothelial cell (EC) biology, we generated mice with catalytic inactivation of one SHIP2 allele selectively in ECs (ECSHIP2Δ/+). Hyperinsulinemic-euglycemic clamping studies revealed that ECSHIP2Δ/+ was resistant to insulin-stimulated glucose uptake in adipose tissue and skeletal muscle compared with littermate controls. ECs from ECSHIP2Δ/+ mice had increased basal expression and activation of PI3K downstream targets, including Akt and endothelial nitric oxide synthase, although incremental activation by insulin and shear stress was impaired. Insulin-mediated vasodilation was blunted in ECSHIP2Δ/+ mice, as was aortic nitric oxide bioavailability. Acetylcholine-induced vasodilation was also impaired in ECSHIP2Δ/+ mice, which was exaggerated in the presence of a superoxide dismutase/catalase mimetic. Superoxide abundance was elevated in ECSHIP2Δ/+ ECs and was suppressed by PI3K and NADPH oxidase 2 inhibitors. These findings were phenocopied in healthy human ECs after SHIP2 silencing. Our data suggest that endothelial SHIP2 is required to maintain normal systemic glucose homeostasis and prevent oxidative stress-induced endothelial dysfunction.

Intrauterine and lactation exposure to fluoxetine blunted in the offspring the aortic adaptive response induced by acute restraint stress

Selective serotonin reuptake inhibitors are the most widely prescribed antidepressants to women during pregnancy. Maternal treatment with fluoxetine can expose fetuses and neonates to higher levels of serotonin that plays a role in stress response. Thus, the aim of the study was to evaluate whether maternal treatment with fluoxetine interferes with aorta reactivity of adult male offspring after acute restraint stress. Wistar rats were gavaged with fluoxetine (5mg/kg/day) or water (control) during pregnancy and lactation. The experiments were performed in adult male offspring, treated or not with reserpine (4mg/Kg, ip, 28h before the experimental protocol). Fluoxetine and control rats were submitted to a single restraint stress session (ST) for 1h. Curves to phenylephrine were performed in thoracic aorta with endothelium. Aortic nitric oxide (NOx) were evaluated by the Griess method. The aortic contraction induced by phenylephrine was similar between control and fluoxetine rats. The acute stress reduced contraction in aorta of control ST compared to control, and L-NAME equaled this response. In fluoxetine rats, ST did not change the aortic constriction. Reserpine treatment restored the vasoconstriction in control ST, but did not interfere with aortic contraction in control, fluoxetine or fluoxetine ST. The NOx concentration was higher in aortas from control ST than control rats, and reserpine reduced NOx levels of control ST. The NOx concentration was similar between fluoxetine and fluoxetine ST rats, treated or not with reserpine. In conclusion, maternal treatment with fluoxetine blunted acute restraint stress-induced NO system activation and aortic adaptation in adult offspring.

Nitric oxide mediates aortic disease in mice deficient in the metalloprotease Adamts1 and in a mouse model of Marfan syndrome.

Heritable thoracic aortic aneurysms and dissections (TAAD), including Marfan syndrome (MFS), currently lack a cure, and causative mutations have been identified for only a fraction of affected families. Here we identify the metalloproteinase ADAMTS1 and inducible nitric oxide synthase (NOS2) as therapeutic targets in individuals with TAAD. We show that Adamts1 is a major mediator of vascular homeostasis, given that genetic haploinsufficiency of Adamts1 in mice causes TAAD similar to MFS. Aortic nitric oxide and Nos2 levels were higher in Adamts1-deficient mice and in a mouse model of MFS (hereafter referred to as MFS mice), and Nos2 inactivation protected both types of mice from aortic pathology. Pharmacological inhibition of Nos2 rapidly reversed aortic dilation and medial degeneration in young Adamts1-deficient mice and in young or old MFS mice. Patients with MFS showed elevated NOS2 and decreased ADAMTS1 protein levels in the aorta. These findings uncover a possible causative role for the ADAMTS1-NOS2 axis in human TAAD and warrant evaluation of NOS2 inhibitors for therapy.

New approaches in protecting against atherosclerosis in experimental model of postmenopause

Objective: The purpose of this study was to evaluate the ability of Myrtus communis (Myrtus communis ) extract to attenuate endothelial dysfunction as well as risk of atherosclerosis in ovaricotmized rats as a common model of postmenopausal. Materials and methods : Sixty female albino rats, weighing 180 ± 20 g were used and divided into four groups (sham, sham+Myrtus communis , ovarictomized (OVX) and treated group).Plasma estrogen, cholesterol, triglycerides (TG), high density lipoprotein (HDL),low density lipoprotein (LDL), asymmetric dimethylarginine (ADMA), von Willebrand factor (vWF),interleukin 1beta (IL-1β) , Lipoxin A4 (LXA4), aortic nitric oxide (NO), superoxide dismutase (SOD),catalase (CAT) and malondialdehyde (MDA) in addition to erythrocyte membrane fatty acids were determined. Results: Ovaricotmized rats showed a significant increase in inflammatory and oxidant parameters while, Myrtus communis extract administration in a dose of 100 mg/kg body weight for two months attenuates these values in treated group. Conclusions: Myrtus communis extract confirmed our idea in protecting from atherosclerosis and endothelial dysfunction in ovarictomized rats due to its high content of anti-oxidant and anti-inflammatory compounds in addition to its high content of ω-3 fatty acids.

NOX isoforms in the development of abdominal aortic aneurysm

Oxidative stress plays an important role in the formation of abdominal aortic aneurysm (AAA), and we have recently established a causal role of uncoupled eNOS in this severe human disease. We have also shown that activation of NADPH oxidase (NOX) lies upstream of uncoupled eNOS. Therefore, identification of the specific NOX isoforms that are required for eNOS uncoupling and AAA formation would ultimately lead to novel therapies for AAA. In the present study, we used the Ang II infused hph-1 mice to examine the roles of NOX isoforms in the development of AAA. We generated double mutants of hph-1-NOX1, hph-1-NOX2, hph-1-p47phox, and hph-1-NOX4. After two weeks of Ang II infusion, the incidence rate of AAA substantially dropped from 76.5% in Ang II infused hph-1 mice (n=34) to 11.1%, 15.0%, 9.5% and 0% in hph-1-NOX1 (n=27), hph-1-NOX2 (n=40), hph-1-p47phox (n=21), and hph-1-NOX4 (n=33) double mutant mice, respectively. The size of abdominal aortas of the four double mutant mice, determined by ultrasound analyses, was significantly smaller than the hph-1 mice. Aortic nitric oxide and H4B bioavailabilities were markedly improved in the double mutants, while superoxide production and eNOS uncoupling activity were substantially diminished. These effects seemed attributed to an endothelial specific restoration of dihydrofolate reductase expression and activity, deficiency of which has been shown to induce eNOS uncoupling and AAA formation in both Ang II-infused hph-1 and apoE null animals. In addition, over-expression of human NOX4 N129S or T555S mutant newly identified in aneurysm patients increased hydrogen peroxide production, further implicating a relationship between NOX and human aneurysm. Taken together, these data indicate that NOX isoforms 1, 2 or 4 lies upstream of dihydrofolate reductase deficiency and eNOS uncoupling to induce AAA formation. These findings may promote development of novel therapeutics for the treatment of the disease by inhibiting NOX signaling.

Phenolics from Garcinia mangostana alleviate exaggerated vasoconstriction in metabolic syndrome through direct vasodilatation and nitric oxide generation.

BackgroundExaggerated vasoconstriction plays a very important role in the hypertension, a major component of metabolic syndrome (MetS). In the current work, the potential protective effect of methanol extract of fruit hulls of Garcinia mangostana L. on the exaggerated vasoconstriction in MetS has been investigated. In addition, the bioactive fraction and compounds as well as the possible mechanism of action have been illustrated.MethodsThe effect of methanol extract of G. mangostana (GMT) fruit hulls on the vascular reactivity of aorta isolated from animals with MetS was investigated through bioassay-guided fractionation procedures. GMT was partitioned with chloroform (I) and the remaining mother liquor was fractionated on a Diaion HP-20 with H2O, 50 and 100 % methanol to give fractions II, III, and IV, respectively. The effect of total extract (GMT), bioactive fraction and the bioactive compounds on the vasoconstriction were examined in aortae isolated from animals with MetS by incubation for 30 min before exposing aortae to cumulative concentrations of phenylephrine (PE). The direct relaxant effect was also examined by adding cumulative concentrations of the bioactive fraction and its bioactive compounds to PE precontracted vessels. In addition, aortic nitric oxide (NO) and reactive oxygen species (ROS) production was investigated.ResultsBioassay-guided fractionation of GMT revealed isolation of garcimangosone D (1), aromadendrin-8-C-β-D-glucopyranoside (2), 2,4,3′-trihydroxy benzophenone-6-O-β-D-glucopyranoside (3), maclurin-6-O-β-D-glucopyranoside (rhodanthenone) (4), epicatechin (5), and 2,3′,4,5′,6-pentahydroxy benzophenone (6). Only compounds 2, 4, and 5 significantly alleviated the exaggerated vasoconstriction of MetS aortae and in the same time showed significant vasodilation of PE pre-contracted aortae. To further illustrate the mechanism of action, the observed vasodilation was completely blocked by the nitric oxide (NO) synthase inhibitor, Nω-nitro-L-arginine methyl ester hydrochloride and inhibited by guanylate cyclase inhibitor, methylene blue. However, vasodilation was not affected by the potassium channel blocker, tetraethylammonium or the cyclooxygenase inhibitor, indomethacin. In addition, compounds 2, 4, and 5 stimulated NO generation from isolated aortae to levels comparable with acetylcholine. Furthermore, 4 and 5 inhibited reactive oxygen species generation in MetS aortae.ConclusionThe phenolic compounds 2, 4, and 5 ameliorated the exaggerated vasoconstriction in MetS aortae through vasodilatation-NO generation mechanism.Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-016-1340-5) contains supplementary material, which is available to authorized users.

Modulation of systemic and aortic nitric oxide by melatonin and n-3 polyunsaturated fatty acids in isoproterenol affected spontaneously hypertensive and normotensive Wistar rats.

We aimed to explore the effects of melatonin and n-3 polyunsaturated fatty acids (PUFA) supplementation on plasma and aortic nitric oxide (NO) levels in isoproterenol (Iso) affected spontaneously hypertensive (SHR) and Wistar rats. Untreated control rats were compared with Iso injected (118 mg/kg, s.c.) rats, and Iso injected plus supplemented with melatonin (10 mg/kg, p.o.) or PUFA (1.68 g/kg, p.o.) for two months. Plasma and aortic basal, L-NAME inhibited, adrenaline and acetylcholine stimulated NO were determined using Griess method. Plasma NO levels were lower in SHR versus Wistar rats. Iso decreased NO in Wistar while not in SHR. PUFA but not melatonin intake of Iso treated SHR increased plasma NO along with a decrease in systolic blood pressure. Basal aortic NO level was higher in SHR than Wistar rats and not altered by Iso. Intake of melatonin increased but PUFA decreased basal NO levels in Wistar+Iso and did not affect in SHR+Iso rats. Acetylcholine and adrenaline induced aortic NO release was significantly increased in Wistar+Iso but not SHR+Iso group. Melatonin intake increased Ach induced aortic NO in Wistar+Iso and SHR+Iso groups, whereas there was no effect of PUFA intake. Findings suggest that PUFA modulates plasma and melatonin aortic NO levels of isoproterenol affected rats in a strain-dependent manner.

Decreased bioavailability of nitric oxide in aorta from ovariectomized senescent mice. Role of cyclooxygenase

This study investigates the effects of aging and/or ovariectomy on vascular reactivity to thromboxane A2 (TXA2) receptor stimulation with U46619, and the modulation by nitric oxide (NO) and cyclooxygenase (COX) in aorta from female senescence-accelerated mice (SAMP8) and from senescence resistant mice (SAMR1). Five-month-old female SAMR1 and SAMP8 were divided into three groups: sham-operated, ovariectomized and ovariectomized plus estradiol. Twenty-eight days after surgery, thoracic aortic rings were mounted for isometric recording of tension and concentration–response curves for U46619 (10−10–3×10−7M) were performed in the absence and in the presence of the NO synthase inhibitor NG-nitro-l-arginine methyl ester (L-NAME, 10−4M) and/or COX inhibitor indomethacin (10−5M). Vascular superoxide production was detected by dihydroethidium staining on sections of thoracic aorta. NO bioavailability in response to U46619 was suppressed by estrogen withdrawn in young and senescent mice and was restored by the administration of estradiol. In the presence of indomethacin, contractions to U46619 decreased in all groups indicating an aging- and estrogen-dependent modulation of contractile prostanoids. The simultaneous incubation of L-NAME and indomethacin did not change the maximal responses and sensitivities to TXA2 in any group in comparison with untreated aortic segments. The superoxide generation induced by TXA2 was greater in aorta from SAMP8 than in SAMR1. Moreover, in ovariectomized groups superoxide production was further increased and treatment with 17β-estradiol reverted the effects of the ovariectomy. Inhibition of COX with indomethacin prevented the U46619-induced increase in superoxide formation. Our results indicate that NO bioavailability in response to TP receptor activation is both estrogen- and aging-dependent. TXA2 induced contractions are partially mediated by COX activation. Both aging and ovariectomy enhanced COX-dependent component of the TXA2-induced contraction. It is noteworthy that in the absence of estrogen, COX inhibition induces an increase of NO bioavailability. Therefore, in senescent female mice with an experimental menopause, TP-receptor stimulation is responsible for COX activation and enhanced superoxide generation, which may result in reduced NO bioavailability. These effects were reversed by estrogen administration.

Consequences of exercising on ischemia-reperfusion injury in type 2 diabetic Goto-Kakizaki rat hearts: role of the HO/NOS system.

BackgroundIt is well established that physical exercise continues to be one of the most valuable forms of non-pharmacological therapy against diabetes mellitus; however, the precise mechanism remains unknown. The aim of this study was to investigate the cardioprotective effect of voluntary exercise in the Goto-Kakizaki type 2 diabetic rat heart against ischemia–reperfusion injury and to clarify its biochemical background, focusing on the nitric oxide synthase/heme oxygenase system.MethodsOne group of male Goto-Kakizaki rats were allowed voluntary exercise, whereas others were kept sedentary for 6 weeks. At the end of the 6th week the hearts were isolated from both groups and subjected to 45-min coronary occlusion followed by 120-min reperfusion. The infarct size was evaluated by means of triphenyltetrazolium chloride staining. The cardiac and aortic nitric oxide synthase/heme oxygenase activities, plasma leptin and glucose concentrations were also assessed.ResultsThe sedentary state prior to the ischemia–reperfusion injury was associated with a significantly higher infarct size (24.56 ± 2.21 vs. 16.66 ± 1.87 %) as compared with that in the voluntary wheel-running group. Exercise altered the constitutive nitric oxide synthase activity; an enhancement was evident in the cardiac (42.5 ± 2.72 vs. 75.6 ± 13.34 pmol/min/mg protein) and aortic tissues (382.5 ± 66.57 vs. 576.9 ± 63.16 pmol/min/mg protein). Exercise lead to a higher heme oxygenase activity (0.68 ± 0.08 vs. 0.92 ± 0.04 nmol bilirubin/h/mg protein) in the diabetic rat hearts. Exercise was associated with lower plasma leptin (192.23 ± 7.22 vs. 169.65 ± 4.6 ng/L) and blood glucose (19.61 ± 0.76 vs. 14.58 ± 0.88 mmol/L) levels.ConclusionsThese results indicate the beneficial role of exercise against myocardial ischemia–reperfusion injury in diabetic rats. These observations in experimental diabetes suggest that the cytoprotective mechanism of exercise involves modulation of the nitric oxide synthase/heme oxygenase system and metabolic parameters that may be responsible for cardioprotection.Electronic supplementary materialThe online version of this article (doi:10.1186/s13098-015-0080-x) contains supplementary material, which is available to authorized users.