Chronic ethanol consumption increases reactive oxygen species generation and the synthesis of pro-inflammatory proteins in the heart through TNFR1-dependent mechanisms.

We evaluated the role of tumor necrosis factor (TNF)-α receptor 1 (TNFR1) on ethanol-induced cardiac dysfunction. Male C57BL/6J wild-type (WT) or TNFR1-deficient mice (TNFR1-/-) were treated with ethanol (20% v/v) for 10 weeks. Increased protein expression of TNFR1 and NFκB p65 was detected in the left ventricle (LV) of WT mice chronically treated with ethanol. Echocardiographic analysis showed that ethanol consumption increased left ventricular posterior wall end-diastolic diameter and left ventricular posterior wall end-systolic diameter in WT, but not TNFR1-/- mice. Increased levels of TNF-α, interleukin (IL)-6, superoxide anion (O2-), thiobarbituric acid reactive substances (TBARS) as well as increased nitrotyrosine immunostaining were detected in the LV from WT, but not TNFR1-/- mice. Conversely, treatment with ethanol decreased nitrate/nitrite (NOx) concentration in the LV. Histopathological analysis showed that ethanol did not induce inflammatory infiltrates, necrosis or edema in the LV. No differences in the ventricular expression of iNOS, Nox2 or COX-2 as well as in the activity of superoxide dismutase (SOD), myeloperoxidase (MPO) and N-acetyl-beta-D-glucosaminidase (NAG) were found after treatment with ethanol. Our study provided novel evidence that ethanol consumption augmented the production of reactive oxygen species (ROS) and the synthesis of pro-inflammatory proteins in the LV through TNFR1-dependent mechanisms. These findings provided novel mechanistic insights about the contribution of TNFR1 in the initial steps of the cardiac damage induced by ethanol.

Ethanol consumption favors pro-contractile phenotype of perivascular adipose tissue: A role for interleukin-6.

Perivascular adipose tissue (PVAT) exerts anticontractile effect, but under non-physiological conditions it may contribute to vascular dysfunction by releasing pro-inflammatory cytokines. Since PVAT is an important source of interleukin (IL)-6, we evaluated whether this cytokine would contribute to ethanol-induced vascular dysfunction. With this purpose, male C57BL/6 wild-type (WT) or IL-6-deficient mice (IL-6-/-) were treated with ethanol for 12 weeks. Increased blood pressure was evidenced after 4 and 6 weeks of treatment with ethanol in WT and IL-6-/- mice, respectively. In WT mice, ethanol increased plasma and PVAT levels of IL-6. Ethanol favoured pro-contractile phenotype of PVAT in mesenteric arteries from WT, but not IL-6-deficient mice. Functional studies showed that tiron [(a scavenger of superoxide (O2-)] reversed the pro-contractile effect of PVAT in mesenteric arteries from ethanol-treated mice. Ethanol increased the levels of O2- in PVAT from WT mice. Ethanol-induced increase in O2- generation was higher in arteries with PVAT from WT mice when compared to IL-6-deficient mice. Treatment with ethanol augmented myeloperoxidase activity in the mesenteric arterial bed (MAB; with or without PVAT) from WT, but not IL-6-deficient mice. In conclusion, IL-6 contributes to the pro-contractile effect of PVAT by a mechanism that involves increase in ROS generation. Additionally, IL-6 mediates intravascular recruitment of neutrophils in response to ethanol and plays a role in the early stages of ethanol-induced hypertension. Collectively, our findings provide novel evidence for a role of IL-6 in the vascular dysfunction induced by ethanol.

Interleukin-10 limits the initial steps of the cardiorenal damage induced by ethanol consumption.

AIMS: Reactive oxygen species (ROS) and pro-inflammatory cytokines play a critical role in organ damage induced by ethanol consumption. Interleukin (IL)-10 maintain tissue homeostasis through restriction of excessive inflammatory responses and inhibition of ROS generation. These responses limit unnecessary tissue damage in the cardiorenal system. We hypothesized that IL-10 would limit the deleterious effects induced by ethanol consumption in the cardiorenal system. MATERIALS AND METHODS: Male C57BL/6J wild-type (WT) or IL10-deficient mice (IL-10-/-) were treated with ethanol (20% v/v) for 6 weeks. KEY FINDINGS: IL-10 deficiency was associated with an increased mortality rate. Ethanol consumption decreased plasma levels of IL-10 in WT mice. Increased levels of IL-6 were detected in the aorta from IL-10-deficient mice, but not WT mice. No alterations in the levels of urea, creatinine, sodium, potassium or creatine kinase (CK)-MB were found after treatment with ethanol. Augmented concentration of thiobarbituric acid reactive substances (TBARS) was found in the left ventricle (LV) of IL-10-deficient mice, but not WT mice. Increased levels of superoxide anion (O2-) were found in the renal cortex of both WT and IL-10-deficient mice. Renal cortex from WT mice chronically treated with ethanol showed decreased levels of H2O2. No changes in the expression of Nox1, Nox4 or catalase were found in the renal cortex from ethanol-treated mice. SIGNIFICANCE: IL-10 limited the production of ROS and the synthesis of pro-inflammatory cytokines induced by ethanol in the cardiorenal system. These findings provided novel evidence that IL-10 counteracted the initial mechanisms whereby ethanol induces its cardiorenal damages.

Three Generations of ß-blockers: History, Class Differences and Clinical Applicability.

BACKGROUND: Beta-adrenergic receptors are expressed in cardiomyocytes and activated by either noradrenaline released from sympathetic synapses or circulating catecholamines. Their corresponding receptors have three subtypes, namely, ß1, ß2 and ß3, which are members of the G protein-coupled receptors (GPCRs) family. Activation of ß1-adrenergic receptors causes various physiological reactions including cardiac contraction and renin secretion from juxtaglomerular cells of the kidney. Antagonists of ß-adrenergic receptors, known as ß-blockers, have been used effectively for over four decades and have beneficial effects in the treatment of cardiovascular diseases. There are three generations of ß-blockers according to their pharmacological properties. Firstgeneration ß-blockers are non-selective, blocking both ß1- and ß2-receptors; second-generation ß- blockers are more cardioselective in that they are more selective for ß1-receptors; and thirdgeneration ß-blockers are highly selective drugs for ß1-receptors. The latter also display vasodilator actions by blocking α1-adrenoreceptors and activating ß3-adrenergic receptors. In addition, thirdgeneration ß-blockers exhibit angiogenic, antioxidant, anti-proliferative, anti-hypertrophic and antiapoptotic activities among other effects that are still under investigation. CONCLUSION: The objective of this review is to describe the evolution observed during the development of the three distinctive generations, thereby highlighting the advantages of third-generation ß- blockers over the other two drug classes.

Nebivolol prevents vascular oxidative stress and hypertension in rats chronically treated with ethanol.

BACKGROUND AND AIMS: Chronic ethanol consumption is associated with hypertension and atherosclerosis. Vascular oxidative stress is described as an important mechanism whereby ethanol predisposes to atherosclerosis. We hypothesized that nebivolol would prevent ethanol-induced hypertension and vascular oxidative stress. METHODS: Male Wistar rats were treated with ethanol 20% (vol./vol.) or nebivolol (10 mg/kg/day, p. o., gavage), a selective ß1-adrenergic receptor antagonist. RESULTS: Ethanol-induced increase in blood pressure and in the circulating levels of adrenaline and noradrenaline was prevented by nebivolol. Similarly, nebivolol prevented ethanol-induced increase in plasma levels of renin, angiotensin I and II. Chronic ethanol consumption increased the aortic levels of superoxide anion (O2-), thiobarbituric acid reactive species (TBARS) as well as the expression of Nox1 and nitrotyrosine immunostaining in the rat aorta. Treatment with nebivolol prevented these responses. The decrease in aortic levels of nitrate/nitrite (NOx) induced by ethanol was prevented by the treatment with nebivolol. Finally, nebivolol attenuated ethanol-induced increase in phenylephrine- and noradrenaline-induced contraction of endothelium-intact and endothelium-denuded aortic rings. CONCLUSIONS: The novelty of our study is that nebivolol prevented ethanol-induced hypertension and vascular oxidative stress. Additionally, we showed that the sympathetic nervous system (SNS) and the renin-angiotensin system (RAS) are important endogenous mediators of the cardiovascular effects of ethanol.

Chronic ethanol consumption increases vascular oxidative stress and the mortality induced by sub-lethal sepsis: Potential role of iNOS.

We hypothesized that long-term ethanol consumption would increase the mortality and aggravate the deleterious effects of sub-lethal cecal ligation and puncture (SL-CLP) in the vasculature by inducing the expression of inducible nitric oxide (NO) synthase (iNOS). Male C57BL/6J wild-type (WT) or iNOS-deficient mice (iNOS-/-) were treated with ethanol (20% v/v) for 12 weeks and then subjected to SL-CLP. Mice were killed 24 h post-operatively or followed six days for survival. Septic ethanol-treated mice showed a higher mortality than septic WT mice. However, septic iNOS-deficient mice treated with ethanol showed a decreased mortality rate when compared to ethanol-treated WT mice. Ethanol and SL-CLP augmented superoxide anion (O2-) generation in the mesenteric arterial bed (MAB) of both WT and iNOS-deficient mice. Treatment with ethanol and SL-CLP enhanced lipoperoxidation in the MAB of WT, but not iNOS-deficient mice. SL-CLP enhanced nitrate/nitrite (NOx) concentrations in the MAB of WT, but not iNOS-deficient mice. Both, ethanol and SL-CLP increased TNF-α and IL-6 levels in the MAB. Treatment with ethanol as well as SL-CLP up-regulated the expression of iNOS in the MAB of WT mice. The major finding of our study is that chronic ethanol consumption increases the mortality induced by SL-CLP and that iNOS plays a role in such response. Although ethanol led to vascular alterations, it did not aggravate the vascular injury induced by SL-CLP. Finally, iNOS mediated the increase in oxidative stress and pro-inflammatory cytokines induced by SL-CLP in the vasculature.

Data on the effects of losartan on protein expression, vascular reactivity and antioxidant capacity in the aorta of ethanol-treated rats.

We describe the effects of losartan, a selective AT1 receptor antagonist on the alterations induced by treatment with ethanol in the rat aorta. The data shown here are related to the article entitled "Angiotensin type 1 receptor mediates chronic ethanol consumption-induced hypertension and vascular oxidative stress" (P. Passaglia, C.S. Ceron, A.S. Mecawi, J. Antunes-Rodrigues, E.B. Coelho, C.R. Tirapelli, 2015) [1]. Here we include new data on the protective effect of losartan against ethanol-induced oxidative stress. Male Wistar rats treated for 2 weeks with ethanol (20%, vol./vol.) exhibited increased aortic production of reactive oxygen species (ROS) and losartan (10 mg/kg/day; p.o. gavage) prevented this response. Ethanol did not alter the expression of eNOS in the rat aorta. Losartan prevented ethanol-induced increase in the aortic expression of nNOS. Neither ethanol nor losartan affected superoxide dismutase (SOD) or catalase (CAT) activities in the rat aorta. Treatment with ethanol increased the contraction induced by phenylephrine in both endothelium-intact and endothelium-denuded aortas and these responses were prevented by losartan. Conversely, neither ethanol nor losartan affected the endothelium-dependent relaxation induced by acetylcholine.

Nebivolol prevents ethanol-induced reactive oxygen species generation and lipoperoxidation in the rat kidney by regulating NADPH oxidase activation and expression.

We studied whether the ß1-adrenergic antagonist nebivolol would prevent ethanol-induced reactive oxygen species generation and lipoperoxidation in the rat renal cortex. Male Wistar rats were treated with ethanol (20% v/v) for 2 weeks. Nebivolol (10mg/kg/day; p.o. gavage) prevented both the increase in superoxide anion (O2-) generation and thiobarbituric acid reactive substances (TBARS) concentration induced by ethanol in the renal cortex. Ethanol decreased nitrate/nitrite (NOx) concentration in the renal cortex, and nebivolol prevented this response. Nebivolol did not affect the reduction of hydrogen peroxide (H2O2) concentration induced by ethanol. Nebivolol prevented the ethanol-induced increase of catalase (CAT) activity. Both SOD activity and the levels of reduced glutathione (GSH) were not affected by treatment with nebivolol or ethanol. Neither ethanol nor nebivolol affected the expression of Nox1, Nox4, eNOS, nNOS, CAT, Nox organizer 1 (Noxo1), c-Src, p47phox or superoxide dismutase (SOD) isoforms in the renal cortex. On the other hand, treatment with ethanol increased Nox2 expression, and nebivolol prevented this response. Finally, nebivolol reduced the expression of protein kinase (PK) Cδ and Rac1. The major finding of our study is that nebivolol prevented ethanol-induced reactive oxygen species generation and lipoperoxidation in the kidney by a mechanism that involves reduction on the expression of Nox2, a catalytic subunit of NADPH oxidase. Additionally, we demonstrated that nebivolol reduces NADPH oxidase-derived reactive oxygen species by decreasing the expression of PKCδ and Rac1, which are important activators of NADPH oxidase.

Tumor necrosis factor-α receptor 1 contributes to ethanol-induced vascular reactive oxygen species generation and hypertension.

We evaluated the contribution of tumor necrosis factor-α receptor 1 (TNFR1) to ethanol-induced hypertension and vascular oxidative stress and the possible role of perivascular adipose tissue (PVAT) in such responses. Male C57BL/6 wild-type (WT) or TNFR1-deficient mice (TNFR1-/-) were treated with ethanol (20% vol/vol) for 12 weeks. Ethanol induced an increase in blood pressure in WT mice and TNFR1-/- at 4 and 5 weeks of treatment, respectively. Treatment with ethanol increased tumor necrosis factor-α and interleukin-6 levels in aortas with or without PVAT (PVAT+ and PVAT-, respectively) from WT mice, but not TNFR1-/-. Ethanol increased superoxide anion (O2-) generation, thiobarbituric acid reactive substance concentration, and the activity of superoxide dismutase and catalase in aortas (PVAT- and PVAT+) from WT mice, but not TNFR1-/-. Conversely, ethanol consumption decreased the concentration of nitrate/nitrite in aortas (PVAT- and PVAT+) from WT mice, but not TNFR1-/-. Treatment with ethanol increased myeloperoxidase activity in aortas (PVAT- and PVAT+) from WT mice, but not TNFR1-/-. The major finding of our study is that TNFR1 contributes to ethanol-induced hypertension and oxidative stress in the vasculature. Additionally, TNFR1 plays a role in ethanol-induced increase in proinflammatory cytokines and neutrophils migration. However, PVAT does not counteract or aggravate the effects induced by ethanol.

Reactive oxygen species derived from NAD(P)H oxidase play a role on ethanol-induced hypertension and endothelial dysfunction in rat resistance arteries.

Chronic ethanol consumption is a risk factor for cardiovascular diseases. We studied whether NAD(P)H oxidase-derived reactive oxygen species (ROS) play a role in ethanol-induced hypertension, vascular dysfunction, and protein expression in resistance arteries. Male Wistar rats were treated with ethanol (20 % v/v) for 6 weeks. Ethanol treatment increased blood pressure and decreased acetylcholine-induced relaxation in the rat mesenteric arterial bed (MAB). These responses were attenuated by apocynin (30 mg/kg/day; p.o. gavage). Ethanol consumption increased superoxide anion (O2-) generation and decreased nitrate/nitrite (NO x ) concentration in the rat MAB and apocynin prevented these responses. Conversely, ethanol did not affect the concentration of hydrogen peroxide (H2O2) and reduced glutathione (GSH) or the activity of superoxide dismutase (SOD) and catalase (CAT) in the rat MAB. Ethanol increased interleukin (IL)-10 levels in the rat MAB but did not affect the levels of tumor necrosis factor (TNF)-α, IL-6, or IL-1ß. Ethanol increased the expression of Nox2 and the phosphorylation of SAPK/JNK, but reduced eNOS expression in the rat MAB. Apocynin prevented these responses. However, ethanol treatment did not affect the expression of Nox1, Nox4, p38MAPK, ERK1/2, or SAPK/JNK in the rat MAB. Ethanol increased plasma levels of TBARS, TNF-α, IL-6, IL-1ß, and IL-10, whereas it decreased NO x levels. The major finding of our study is that NAD(P)H oxidase-derived ROS play a role on ethanol-induced hypertension and endothelial dysfunction in resistance arteries. Moreover, ethanol consumption affects the expression and phosphorylation of proteins that regulate vascular function and NAD(P)H oxidase-derived ROS play a role in such responses.

Mechanisms underlying sodium nitroprusside-induced tolerance in the mouse aorta: Role of ROS and cyclooxygenase-derived prostanoids.

AIMS: To determine the role of reactive oxygen species (ROS) on sodium nitroprusside (SNP)-induced tolerance. Additionally, we evaluated the role of ROS on NF-κB activation and pro-inflammatory cytokines production during SNP-induced tolerance. MAIN METHODS: To induce in vitro tolerance, endothelium-intact or -denuded aortic rings isolated from male Balb-c mice were incubated for 15, 30, 45 or 60min with SNP (10nmol/L). KEY FINDINGS: Tolerance to SNP was observed after incubation of endothelium-denuded, but not endothelium-intact aortas for 60min with this inorganic nitrate. Pre-incubation of denuded rings with tiron (superoxide anion (O2-) scavenger), and the NADPH oxidase inhibitors apocynin and atorvastatin reversed SNP-induced tolerance. l-NAME (non-selective NOS inhibitor) and l-arginine (NOS substrate) also prevented SNP-induced tolerance. Similarly, ibuprofen (non-selective cyclooxygenase (COX) inhibitor), nimesulide (selective COX-2 inhibitor), AH6809 (prostaglandin PGF2α receptor antagonist) or SQ29584 [PGH2/thromboxane TXA2 receptor antagonist] reversed SNP-induced tolerance. Increased ROS generation was detected in tolerant arteries and both tiron and atorvastatin reversed this response. Tiron prevented tolerance-induced increase on O2- and hydrogen peroxide (H2O2) levels. The increase onp65/NF-κB expression and TNF-α production in tolerant arteries was prevented by tiron. The major new finding of our study is that SNP-induced tolerance is mediated by NADPH-oxidase derived ROS and vasoconstrictor prostanoids derived from COX-2, which are capable of reducing the vasorelaxation induced by SNP. Additionally, we found that ROS mediate the activation of NF-κB and the production of TNF-α in tolerant arteries. SIGNIFICANCE: These findings identify putative molecular mechanisms whereby SNP induces tolerance in the vasculature.

Ethanol-induced erectile dysfunction and increased expression of pro-inflammatory proteins in the rat cavernosal smooth muscle are mediated by NADPH oxidase-derived reactive oxygen species.

Ethanol consumption is associated with an increased risk of erectile dysfunction (ED), but the molecular mechanisms through which ethanol causes ED remain elusive. Reactive oxygen species are described as mediators of ethanol-induced cell toxicity/damage in distinctive tissues. The enzyme NADPH oxidase is the main source of reactive oxygen species in the endothelium and vascular smooth muscle cells and ethanol is described to increase NADPH oxidase activation and reactive oxygen species generation. This study evaluated the contribution of NADPH oxidase-derived reactive oxygen species to ethanol-induced ED, endothelial dysfunction and production of pro-inflammatory and redox-sensitive proteins in the rat cavernosal smooth muscle (CSM). Male Wistar rats were treated with ethanol (20% v/v) or ethanol plus apocynin (30mg/kg/day; p.o. gavage) for six weeks. Apocynin prevented both the decreased in acetylcholine-induced relaxation and intracavernosal pressure induced by ethanol. Ethanol increased superoxide anion (O2-) generation and catalase activity in CSM, and treatment with apocynin prevented these responses. Similarly, apocynin prevented the ethanol-induced decreased of nitrate/nitrite (NOx), hydrogen peroxide (H2O2) and SOD activity. Treatment with ethanol increased p47phox translocation to the membrane as well as the expression of Nox2, COX-1, catalase, iNOS, ICAM-1 and p65. Apocynin prevented the effects of ethanol on protein expression and p47phox translocation. Finally, treatment with ethanol increased both TNF-α production and neutrophil migration in CSM. The major new finding of this study is that NADPH oxidase-derived reactive oxygen species play a role on chronic ethanol consumption-induced ED and endothelial dysfunction in the rat CSM.

The Labdane Ent-3-Acetoxy-Labda-8(17), 13-Dien-15-Oic Decreases Blood Pressure In Hypertensive Rats.

BACKGROUND: Labdane-type diterpenes induce lower blood pressure via relaxation of vascular smooth muscle; however, there are no studies describing the effects of labdanes in hypertensive rats. OBJECTIVE: The present study was designed to investigate the cardiovascular actions of the labdane-type diterpene ent-3-acetoxy-labda-8(17), 13-dien-15-oic acid (labda-15-oic acid) in two-kidney 1 clip (2K-1C) renal hypertension. METHODS: Vascular reactivity experiments were performed in aortic rings isolated from 2K-1C and normotensive (2K) male Wistar rats. Nitrate/nitrite (NOx) measurement was performed in aortas by colorimetric assay. Blood pressure measurements were performed in conscious rats. RESULTS: Labda-15-oic acid (0.1-300 µmol/l) and forskolin (0.1 nmol/l - 1 µmol/l) relaxed endothelium-intact and endothelium-denuded aortas from both 2K-1C and 2K rats. Labda-15-oic acid was more effective at inducing relaxation in endothelium-intact aortas from 2K pre-contracted with phenylephrine when compared to the endothelium-denuded ones. Forskolin was more potent than labda-15-oic acid at inducing vascular relaxation in arteries from both 2K and 2K-1C rats. Labda-15-oic acid-induced increase in NOx levels was lower in arteries from 2K-1C rats when compared to 2K rats. Intravenous administration of labda-15-oic acid (0.3-3 mg/kg) or forskolin (0.1-1 mg/kg) induced hypotension in conscious 2K-1C and 2K rats. CONCLUSION: The present findings show that labda-15-oic acid induces vascular relaxation and hypotension in hypertensive rats.

Data on the mechanisms underlying succinate-induced aortic contraction.

We describe the mechanisms underlying the vascular contraction induced by succinate. The data presented here are related to the article entitled "Pharmacological characterization of the mechanisms underlying the vascular effects of succinate" (L.N. Leite, N.A. Gonzaga, J.A. Simplicio, G.T. Vale, J.M. Carballido, J.C. Alves-Filho, C.R. Tirapelli, 2016) [1]. Succinate acts as a signaling molecule by binding to a G-protein-coupled receptor termed GPR91, "Citric acid cycle intermediates as ligands for orphan G-protein-coupled receptors" (W. He, F.J. Miao, D.C. Lin, R.T. Schwandner, Z. Wang, J. Gao, J.L. Chen, H. Tian, L. Ling, 2004) [2]. Here we include data on the contractile effect of succinate in the aorta. Succinate contracted both endothelium-intact and endothelium-denuded aortic rings isolated from male Wistar rats or C57BL/6 mice. Succinate was less effective at inducing contraction in arteries isolated from GPR91-deficient mice, when compared to its vascular effect in aortas from wild type mice. SB203508 (p38MAK inhibitor), SP600125 (JNK inhibitor) and Y27632 (Rho-kinase inhibitor) reduced succinate-induced contraction in both endothelium-intact and endothelium-denuded rat aortic rings, while PD98059 (ERK1/2 inhibitor) did not affect succinate-induced contraction. The contractile response induced by succinate on endothelium-intact and endothelium-denuded rat aortic rings was reduced by indomethacin (non-selective cyclooxygenase inhibitor), H7 (protein kinase C inhibitor), verapamil (Ca(2+) channel blocker) and tiron (superoxide anion scavenger).

Acute Ethanol Intake Induces NAD(P)H Oxidase Activation and Rhoa Translocation in Resistance Arteries.

BACKGROUND:: The mechanism underlying the vascular dysfunction induced by ethanol is not totally understood. Identification of biochemical/molecular mechanisms that could explain such effects is warranted. OBJECTIVE:: To investigate whether acute ethanol intake activates the vascular RhoA/Rho kinase pathway in resistance arteries and the role of NAD(P)H oxidase-derived reactive oxygen species (ROS) on such response. We also evaluated the requirement of p47phox translocation for ethanol-induced NAD(P)H oxidase activation. METHODS:: Male Wistar rats were orally treated with ethanol (1g/kg, p.o. gavage) or water (control). Some rats were treated with vitamin C (250 mg/kg, p.o. gavage, 5 days) before administration of water or ethanol. The mesenteric arterial bed (MAB) was collected 30 min after ethanol administration. RESULTS:: Vitamin C prevented ethanol-induced increase in superoxide anion (O2-) generation and lipoperoxidation in the MAB. Catalase and superoxide dismutase activities and the reduced glutathione, nitrate and hydrogen peroxide (H2O2) levels were not affected by ethanol. Vitamin C and 4-methylpyrazole prevented the increase on O2- generation induced by ethanol in cultured MAB vascular smooth muscle cells. Ethanol had no effect on phosphorylation levels of protein kinase B (Akt) and eNOS (Ser1177 or Thr495 residues) or MAB vascular reactivity. Vitamin C prevented ethanol-induced increase in the membrane: cytosol fraction ratio of p47phox and RhoA expression in the rat MAB. CONCLUSION:: Acute ethanol intake induces activation of the RhoA/Rho kinase pathway by a mechanism that involves ROS generation. In resistance arteries, ethanol activates NAD(P)H oxidase by inducing p47phox translocation by a redox-sensitive mechanism. FUNDAMENTO:: O mecanismo da disfunção vascular induzido pelo consumo de etanol não é totalmente compreendido. Justifica-se, assim a identificação de mecanismos bioquímicos e moleculares que poderiam explicar tais efeitos. OBJETIVOS:: Investigar se a ingestão aguda de etanol ativa a via vascular RhoA/Rho quinase em artérias de resistência e o papel das espécies reativas de oxigênio (ERO) derivadas da NAD(P)H oxidase nessa resposta. Nós também avaliamos se ocorreu translocação da p47phox e ativação da NAD(P)H oxidase após o consumo agudo de etanol. MÉTODOS:: Ratos Wistar machos foram tratados com etanol via oral (1g/kg, p.o. gavagem) ou água (controle). Alguns ratos foram tratados com vitamina C (250 mg/kg, p.o. gavagem, 5 dias) antes de água ou etanol. O leito arterial mesentérico (LAM) foi coleado 30 min após a administração de etanol. RESULTADOS:: A vitamina C preveniu o aumento da geração de ânion superóxido (O2 -) e lipoperoxidação no LAM induzidos pelo etanol. A atividade da catalase (CAT), da superóxido dismutase (SOD) e os níveis de glutationa reduzida(GSH), nitrato e peróxido de hidrogênio (H2O2) não foram afetados após a ingestão aguda de etanol. A vitamina C e o 4-metilpirazol preveniram o aumento na geração de O2 - induzido pelo etanol em cultura de células do músculo liso vascular (CMLV). O etanol não afetou a fosforilação da proteína quinase B (Akt) e nem da óxido nítrico sintase endotelial (eNOS) (nos resíduos de Ser1177 ou Thr495) ou a reatividade vascular do LAM. A vitamina C preveniu o aumento da razão membrana:citosol da p47phox e a expressão da RhoA no LAM de rato induzido pelo etanol. CONCLUSÃO:: A ingestão aguda de etanol induz a ativação da via RhoA/Rho quinase por um mecanismo que envolve a geração de ERO. Nas artérias de resistência, o etanol ativa NAD(P)H oxidase induzindo a translocação da p47phox por um mecanismo redox-sensível.

Pharmacological characterization of the mechanisms underlying the vascular effects of succinate.

We investigated the mechanisms underlying the vascular effects of succinate. Vascular reactivity experiments were performed in aortic rings isolated from male Wistar rats and C57BL/6 wild type (WT) or GPR91(-/-) mice. Nitrate/nitrite (NOx) was measured colorimetrically whereas 6-keto-prostaglandin F1α (stable product of prostacyclin) was measured by enzyme immunoassay (EIA). Phosphorylation of endothelial nitric oxide synthase (eNOS) was assessed by western immunoblotting. Functional assays revealed that the direct effect of succinate in the vasculature is biphasic. At lower concentrations succinate induced relaxation while at higher concentrations succinate induced vascular contraction. Succinate concentration dependently relaxed rat aortic rings with intact endothelium. Endothelial removal reduced, but not abolished succinate-induced relaxation. Similarly, succinate relaxed endothelium-intact and endothelium-denuded aortas isolated from both C57BL/6 and GPR91(-/-) mice. Pre-incubation of endothelium-intact, but not endothelium-denuded rat aortic rings with l-NAME, indomethacin and tetraethylammonium (TEA) reduced succinate-induced relaxation. In endothelium-intact rings, succinate-induced relaxation was attenuated by ODQ, haemoglobin, Rp-8-Br-Pet-cGMPS, thapsigargin, wortmannin and SC-560. Blockade of K(+) channels with 4-aminopyridine, apamin and charybdotoxin reduced succinate-induced relaxation. Succinate increased the concentration of NOx and 6-keto-prostaglandin F1α as well as eNOS phosphorylation at ser(1177) residue. CaCl2-induced contraction of endothelium-intact or endothelium-denuded aortas was not affected by succinate. The major finding of our study is that it first demonstrates a direct effect of succinate in the vasculature. Succinate displays a biphasic and concentration-dependent effect. The vascular relaxation induced by succinate is partially mediated by endothelial GPR91 receptors via the NO-cGMP pathway, a vasodilator cyclooxygenase (COX) product(s) and the opening of K(+) channels.

Vitamin C prevents the endothelial dysfunction induced by acute ethanol intake.

AIMS: Investigate the effect of ascorbic acid (vitamin C) on the endothelial dysfunction induced by acute ethanol intake. MAIN METHODS: Ethanol (1g/kg; p.o. gavage) effects were assessed within 30min in male Wistar rats. KEY FINDINGS: Ethanol intake decreased the endothelium-dependent relaxation induced by acetylcholine in the rat aorta and treatment with vitamin C (250mg/kg; p.o. gavage, 5days) prevented this response. Ethanol increased superoxide anion (O2(-)) generation and decreased aortic nitrate/nitrite levels and these responses were not prevented by vitamin C. Superoxide dismutase (SOD) and catalase (CAT) activities as well as hydrogen peroxide (H2O2) and reduced glutathione (GSH) levels were not affected by ethanol. RhoA translocation as well as the phosphorylation levels of protein kinase B (Akt), eNOS (Ser(1177) or Thr(495) residues), p38MAPK, SAPK/JNK and ERK1/2 was not affected by ethanol intake. Vitamin C increased SOD activity and phosphorylation of Akt, eNOS (Ser(1177) residue) and p38MAPK in aortas from both control and ethanol-treated rats. Incubation of aortas with tempol prevented ethanol-induced decrease in the relaxation induced by acetylcholine. Ethanol (50mM/1min) increased O2(-) generation in cultured aortic vascular smooth muscle cells (VSMC) and vitamin C did not prevent this response. In endothelial cells, vitamin C prevented the increase on ROS generation and the decrease in the cytosolic NO content induced by ethanol. SIGNIFICANCE: Our study provides novel evidence that vitamin C prevents the endothelial dysfunction induced by acute ethanol intake by a mechanism that involves reduced ROS generation and increased NO availability in endothelial cells.

Contribution of oxidative stress and prostanoids in endothelial dysfunction induced by chronic fluoxetine treatment.

OBJECTIVES: The effects of chronic fluoxetine treatment were investigated on blood pressure and on vascular reactivity in the isolated rat aorta. METHODS AND RESULTS: Male Wistar rats were treated with fluoxetine (10 mg/kg/day) for 21 days. Fluoxetine increased systolic blood pressure. Chronic, but not acute, fluoxetine treatment increased the contractile response induced by phenylephrine, serotonin (5-HT) and KCl in endothelium-intact rat aortas. L-NAME and ODQ did not alter the contraction induced by phenylephrine and 5-HT in aortic rings from fluoxetine-treated rats. Tiron, SC-560 and AH6809 reversed the increase in the contractile response to phenylephrine and 5-HT in aortas from fluoxetine-treated rats. Fluoxetine treatment increased superoxide anion generation (O2(-)) and the expression of cyclooxygenase (COX)-1 in the rat aorta. Reduced expression of nNOS, but not eNOS or iNOS was observed in animals treated with fluoxetine. Fluoxetine treatment increased prostaglandin (PG)F2α levels but did not affect thromboxane (TX)B2 levels in the rat aorta. Reduced hydrogen peroxide (H2O2) levels and increased catalase (CAT) activity were observed after treatment. CONCLUSIONS: The major new finding of our study is that chronic fluoxetine treatment induces endothelial dysfunction, which alters vascular responsiveness by a mechanism that involves increased oxidative stress and the generation of a COX-derived vasoconstrictor prostanoid (PGF2α). Moreover, our results evidenced a relation between the period of treatment with fluoxetine and the magnitude in the increment of blood pressure. Finally, our findings raise the possibility that fluoxetine treatment increases the risk for vascular injury, a response that could predisposes to cardiovascular diseases.

The Labdane Ent-3-Acetoxy-Labda-8(17), 13-Dien-15-Oic Decreases Blood Pressure In Hypertensive Rats / O Labdano Ácido Ent-3-Acetóxi-Labda-8(17), 13-Dieno-15-Óico Reduz Pressão Arterial Em Ratos Hipertensos

Abstract Background: Labdane-type diterpenes induce lower blood pressure via relaxation of vascular smooth muscle; however, there are no studies describing the effects of labdanes in hypertensive rats. Objective: The present study was designed to investigate the cardiovascular actions of the labdane-type diterpene ent-3-acetoxy-labda-8(17), 13-dien-15-oic acid (labda-15-oic acid) in two-kidney 1 clip (2K-1C) renal hypertension. Methods: Vascular reactivity experiments were performed in aortic rings isolated from 2K-1C and normotensive (2K) male Wistar rats. Nitrate/nitrite (NOx) measurement was performed in aortas by colorimetric assay. Blood pressure measurements were performed in conscious rats. Results: Labda-15-oic acid (0.1-300 µmol/l) and forskolin (0.1 nmol/l - 1 µmol/l) relaxed endothelium-intact and endothelium-denuded aortas from both 2K-1C and 2K rats. Labda-15-oic acid was more effective at inducing relaxation in endothelium-intact aortas from 2K pre-contracted with phenylephrine when compared to the endothelium-denuded ones. Forskolin was more potent than labda-15-oic acid at inducing vascular relaxation in arteries from both 2K and 2K-1C rats. Labda-15-oic acid-induced increase in NOx levels was lower in arteries from 2K-1C rats when compared to 2K rats. Intravenous administration of labda-15-oic acid (0.3-3 mg/kg) or forskolin (0.1-1 mg/kg) induced hypotension in conscious 2K-1C and 2K rats. Conclusion: The present findings show that labda-15-oic acid induces vascular relaxation and hypotension in hypertensive rats.

Resumo Fundamento: Diterpenos do tipo labdano induzem uma queda da pressão arterial por meio do relaxamento do músculo liso vascular; todavia, não há estudos que descrevam os efeitos de labdanos em ratos hipertensos. Objetivo: O presente estudo foi desenvolvido para investigar as ações cardiovasculares do labdano ácido ent-3-acetóxi-labda-8(17),13-dieno-15-óico (labda-15-óico) na hipertensão renal dois rins-1 clipe (2R-1C). Métodos: Foram feitos experimentos de reatividade vascular em anéis aórticos isolados de ratos machos 2R-1C e normotensos (2R). A medição de Nitrato/Nitrito (NOx) foi feita nas aortas por meio de ensaio colorimétrico. As medidas de pressão arterial foram feitas em ratos conscientes. Resultados: O ácido labda-15-óico (0,1 - 300 µmol/l) e a forscolina (0,1 nmol/l - 1 µmol/l) relaxaram as aortas com endotélio intacto e as aortas sem endotélio dos ratos 2R-1C e 2R. O labda-15-óico mostrou-se mais eficaz na indução do relaxamento em aortas com endotélio intacto de 2R pré-contraídas com fenilefrina em comparação àquelas sem endotélio. A forscolina mostrou-se mais potente do que o ácido labda-15-óico na indução do relaxamento vascular nas artérias tanto de ratos 2R-1C quanto de ratos 2R. O aumento dos níveis de NOx induzido pelo ácido labda-15-óico foi menor nas artérias de ratos 2R-1C em comparação a ratos 2R. A administração intravenosa de ácido labda-15-óico (0,3-3 mg/kg) ou forscolina (0,1-1 mg/kg) induziu hipertensão em ratos 2R-1C e 2R conscientes. Conclusão: Os presentes resultados mostram que o labda-15-óico induz relaxamento vascular e hipotensão em ratos hipertensos.

Acute Ethanol Intake Induces NAD(P)H Oxidase Activation and Rhoa Translocation in Resistance Arteries / O consumo agudo de etanol induz a ativação da NAD(P)H oxidase e translocação da RhoA em artérias de resistência

Abstract Background: The mechanism underlying the vascular dysfunction induced by ethanol is not totally understood. Identification of biochemical/molecular mechanisms that could explain such effects is warranted. Objective: To investigate whether acute ethanol intake activates the vascular RhoA/Rho kinase pathway in resistance arteries and the role of NAD(P)H oxidase-derived reactive oxygen species (ROS) on such response. We also evaluated the requirement of p47phox translocation for ethanol-induced NAD(P)H oxidase activation. Methods: Male Wistar rats were orally treated with ethanol (1g/kg, p.o. gavage) or water (control). Some rats were treated with vitamin C (250 mg/kg, p.o. gavage, 5 days) before administration of water or ethanol. The mesenteric arterial bed (MAB) was collected 30 min after ethanol administration. Results: Vitamin C prevented ethanol-induced increase in superoxide anion (O2-) generation and lipoperoxidation in the MAB. Catalase and superoxide dismutase activities and the reduced glutathione, nitrate and hydrogen peroxide (H2O2) levels were not affected by ethanol. Vitamin C and 4-methylpyrazole prevented the increase on O2- generation induced by ethanol in cultured MAB vascular smooth muscle cells. Ethanol had no effect on phosphorylation levels of protein kinase B (Akt) and eNOS (Ser1177 or Thr495 residues) or MAB vascular reactivity. Vitamin C prevented ethanol-induced increase in the membrane: cytosol fraction ratio of p47phox and RhoA expression in the rat MAB. Conclusion: Acute ethanol intake induces activation of the RhoA/Rho kinase pathway by a mechanism that involves ROS generation. In resistance arteries, ethanol activates NAD(P)H oxidase by inducing p47phox translocation by a redox-sensitive mechanism.

Resumo Fundamento: O mecanismo da disfunção vascular induzido pelo consumo de etanol não é totalmente compreendido. Justifica-se, assim a identificação de mecanismos bioquímicos e moleculares que poderiam explicar tais efeitos. Objetivos: Investigar se a ingestão aguda de etanol ativa a via vascular RhoA/Rho quinase em artérias de resistência e o papel das espécies reativas de oxigênio (ERO) derivadas da NAD(P)H oxidase nessa resposta. Nós também avaliamos se ocorreu translocação da p47phox e ativação da NAD(P)H oxidase após o consumo agudo de etanol. Métodos: Ratos Wistar machos foram tratados com etanol via oral (1g/kg, p.o. gavagem) ou água (controle). Alguns ratos foram tratados com vitamina C (250 mg/kg, p.o. gavagem, 5 dias) antes de água ou etanol. O leito arterial mesentérico (LAM) foi coleado 30 min após a administração de etanol. Resultados: A vitamina C preveniu o aumento da geração de ânion superóxido (O2 -) e lipoperoxidação no LAM induzidos pelo etanol. A atividade da catalase (CAT), da superóxido dismutase (SOD) e os níveis de glutationa reduzida(GSH), nitrato e peróxido de hidrogênio (H2O2) não foram afetados após a ingestão aguda de etanol. A vitamina C e o 4-metilpirazol preveniram o aumento na geração de O2 - induzido pelo etanol em cultura de células do músculo liso vascular (CMLV). O etanol não afetou a fosforilação da proteína quinase B (Akt) e nem da óxido nítrico sintase endotelial (eNOS) (nos resíduos de Ser1177 ou Thr495) ou a reatividade vascular do LAM. A vitamina C preveniu o aumento da razão membrana:citosol da p47phox e a expressão da RhoA no LAM de rato induzido pelo etanol. Conclusão: A ingestão aguda de etanol induz a ativação da via RhoA/Rho quinase por um mecanismo que envolve a geração de ERO. Nas artérias de resistência, o etanol ativa NAD(P)H oxidase induzindo a translocação da p47phox por um mecanismo redox-sensível.