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Toda N, Ayajiki K. Vascular actions of nitric oxide as affected by exposure to alcohol. Alcohol Alcohol 2010; 45:347-55. [PMID: 20522422 DOI: 10.1093/alcalc/agq028] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Vasodilator substances liberated from endothelial cells, mainly nitric oxide (NO), play important roles in physiologically regulating blood flow and blood pressure and preventing pathological vascular damage. Impairment of these actions promotes the genesis of cardiovascular diseases such as hypertension, cerebral and cardiac hypoperfusion, impaired vasodilatation and atherosclerosis. Low concentrations of alcohol induce increased release of NO from the endothelium due to activation and expression of NO synthase (NOS). In contrast, administration of high concentrations of alcohol or its chronic ingestion impairs endothelial functions in association with reduced NO bioavailability. The endogenous NOS inhibitor asymmetric dimethylarginine may participate in decreased synthesis of NO. Chronic alcohol intake also impairs penile erectile function possibly by interfering with endothelial, but not nitrergic nerve, function. This review article summarizes the vascular actions of NO derived from endothelial and neuronal NOS as affected by alcohol, other than wine, and acetaldehyde in healthy individuals, human materials and various experimental animals.
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Affiliation(s)
- Noboru Toda
- Toyama Institute for Cardiovascular Pharmacology Research, 7-13, 1-Chome, Azuchi-machi, Chuo-ku, Osaka 541-0052, Japan.
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Nisar A, Afzulpurkar N, Tuantranont A, Mahaisavariya B. Three dimensional transient multifield analysis of a piezoelectric micropump for drug delivery system for treatment of hemodynamic dysfunctions. ACTA ACUST UNITED AC 2009; 8:203-18. [PMID: 19030990 DOI: 10.1007/s10558-008-9060-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this paper, we present design of a transdermal drug delivery system for treatment of cardiovascular or hemodynamic disorders such as hypertension. The system comprises of integrated control electronics and microelectromechanical system devices such as micropump, micro blood pressure sensor and microneedle array. The objective is to overcome the limitations of oral therapy such as variable absorption profile and the need for frequent dosing, by fabricating a safe, reliable and cost effective transdermal drug delivery system to dispense various pharmacological agents through the skin for treatment of hemodynamic dysfunction such as hypertension. Moreover, design optimization of a piezoelectrically actuated valveless micropump is presented for the drug delivery system. Because of the complexity in analysis of piezoelectric micropump, which involves structural and fluid field couplings in a complicated geometrical arrangement, finite element (FE) numerical simulation rather than an analytical system has been used. The behavior of the piezoelectric actuator with biocompatible polydimethylsiloxane membrane is first studied by conducting piezoelectric analysis. Then the performance of the valveless micropump is analyzed by building a three dimensional electric-solid-fluid model of the micropump. The effect of geometrical dimensions on micropump characteristics and efficiency of nozzle/diffuser elements of a valveless micropump is investigated in the transient analysis using multiple code coupling method. The deformation results of the membrane using multifield code coupling analysis are in good agreement with analytical as well as results of single code coupling analysis of a piezoelectric micropump. The analysis predicts that to enhance the performance of the micropump, diffuser geometrical dimensions such as diffuser length, diffuser neck width and diffuser angle need to be optimized. Micropump flow rate is not strongly affected at low excitation frequencies from 10 to 200 Hz. The excitation voltage is the more dominant factor that affects the flow rate of the micropump as compared with the excitation frequency. However, at extremely high excitation frequencies beyond 8,000 Hz, the flow rate drops as the membrane exhibits multiple bending peaks which is not desirable for fluid flow. Following the extensive numerical analysis, actual fabrication and performance characterization of the micropump is presented. The performance of the micropump is characterized in terms of piezoelectric actuator deflection and micropump flow rate at different operational parameters. The set of multifield simulations and experimental measurement of deflection and flow rate at varying voltage and excitation frequency is a significant advance in the study of the electric-solid-fluid coupled field effects as it allows transient, three dimensional piezoelectric and fluid analysis of the micropump thereby facilitating a more realistic multifield analysis. The results of the present study will also help to conduct relevant strength duration tests of integrated drug delivery device with micropump and microneedle array in future.
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Affiliation(s)
- Asim Nisar
- School of Engineering and Technology, Asian Institute of Technology (AIT), Pathum Thani, Thailand.
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El-Mas MM, Fan M, Abdel-Rahman AA. Endotoxemia-mediated induction of cardiac inducible nitric-oxide synthase expression accounts for the hypotensive effect of ethanol in female rats. J Pharmacol Exp Ther 2007; 324:368-75. [PMID: 17925480 DOI: 10.1124/jpet.107.127498] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
We have recently shown that intragastric (i.g.) ethanol lowers blood pressure (BP) in conscious female rats via a reduction in cardiac output (CO). However, the mechanisms implicated in these hemodynamic effects of ethanol are not known. Therefore, we tested the hypothesis that ethanol-evoked endotoxemia mediates the reduction in CO via enhanced myocardial inducible nitric-oxide synthase (iNOS) expression. Immunoblot (myocardial iNOS), biochemical (plasma endotoxin and nitrite/nitrate), and integrative [BP, heart rate, CO, stroke volume (SV), and total peripheral resistance (TPR)] studies were conducted in conscious female rats that received i.g. ethanol (1 g/kg) in the absence or presence of 1400W (N-(3-[aminomethyl]benzyl) acetamidine) or ampicillin to selectively inhibit iNOS and to eliminate endogenous endotoxin, respectively. Ethanol-evoked hypotension coincided with reductions in CO and SV and increases in: 1) TPR, 2) plasma endotoxin and nitrite/nitrate, and 3) myocardial iNOS expression. These effects of ethanol were virtually abolished in rats pretreated with ampicillin (200 mg/kg/day for 2 days by gavage) or with 1400W (5 mg/kg i.p.) except for the increase in plasma endotoxin, which persisted in 1400W-pretreated rats. These findings yield insight into the mechanistic role of endotoxin-myocardial iNOS signaling in the cardiodepressant action of ethanol, which accounts for its hypotensive effect in conscious female rats.
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Affiliation(s)
- Mahmoud M El-Mas
- Department of Pharmacology, School of Medicine, East Carolina University, Greenville, NC 27834, USA
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Prandota J. Recurrent headache as the main symptom of acquired cerebral toxoplasmosis in nonhuman immunodeficiency virus-infected subjects with no lymphadenopathy: the parasite may be responsible for the neurogenic inflammation postulated as a cause of different types of headaches. Am J Ther 2007; 14:63-105. [PMID: 17303977 DOI: 10.1097/01.mjt.0000208272.42379.aa] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Headache and/or migraine, a common problem in pediatrics and internal medicine, affect about 5% to 10% children and adolescents, and nearly 30% of middle-aged women. Headache is also one of the most common clinical manifestations of acquired Toxoplasma gondii infection of the central nervous system (CNS) in immunosuppressed subjects. We present 11 apparently nonhuman immunodeficiency virus-infected children aged 7 to 17 years (8 girls, 3 boys) and 1 adult woman with recurrent severe headaches in whom latent chronic CNS T. gondii infection not manifested by enlarged peripheral lymph nodes typical for toxoplasmosis, was found. In 7 patients, the mean serum IgG Toxoplasma antibodies concentration was 189 +/- 85 (SD) IU/mL (range 89 to 300 IU/mL), and in 5 other subjects, the indirect fluorescent antibody test titer ranged from 1:40 to 1:5120 IU/mL (n= <1:10 IU/mL). Some of the patients suffered also from atopic dermatitis (AD) and were exposed to cat and/or other pet allergens, associated with an increased IL-4 and decreased IFN-gamma production. These cytokine irregularities caused limited control of cerebral toxoplasmosis probably because IL-4 down-regulated both the production of IFN-gamma and its activity, and stimulated production of a low NO-producing population of monocytes, which allowed cysts rupture, increased parasite multiplication and finally reactivation of T. gondii infection. The immune studies performed in 4 subjects showed a decreased percentage of T lymphocytes, increased total number of lymphocytes B and serum IgM concentration, and impaired phagocytosis. In addition, few of them had also urinary tract diseases known to produce IL-6 that can mediate immunosuppressive functions, involving induction of the anti-inflammatory cytokine IL-10. These disturbances probably resulted from the host protective immune reactions associated with the chronic latent CNS T. gondii infection/inflammation. This is consistent with significantly lower enzyme indoleamine 2,3-dioxygenase (IDO) activity reported in atopic than in nonatopic individuals, and an important role that IDO and tryptophan degradation pathways plays in both, the host resistance to T. gondii infection and its reactivation. Analysis of literature information on the subjects with different types of headaches caused by foods, medications, and other substances, may suggest that their clinical symptoms and changes in laboratory data result at least in part from interference of these factors with dietary tryptophan biotransformation pathways. Several of these agents caused headache attacks through enhancing NO production via the conversion of arginine to citrulline and NO by the inducible nitric oxide synthase enzyme, which results in the high-output pathway of NO synthesis. This increased production of NO is, however, quickly down-regulated by NO itself because this biomolecule can directly inactivate NOS, may inhibit Ia expression on IFN-gamma-activated macrophages, which would limit antigen-presenting capability, and block T-cell proliferation, thus decreasing the antitoxoplasmatic activity. Moreover, NO inhibits IDO activity, thereby suppressing kynurenine formation, and at least one member of the kynurenine pathway, 3-hydroxyanthranilic acid, has been shown to inhibit NOS enzyme activity, the expression of NOS mRNA, and activation of the inflammatory transcription factor, nuclear factor-kB. In addition, the anti-inflammatory cytokines IL-4 and IL-10, TGF-beta, and a cytokine known as macrophage deactivating factor, have been shown to directly modulate NO production, sometimes expressing synergistic activity. On the other hand, IL-4 and TGF-beta can suppress IDO activity in some cells, for example human monocytes and fibroblasts, which is consistent with metabolic pathways controlled by IDO being a significant contributor to the proinflammatory system. Also, it seems that idiopathic intracranial hypertension, pseudotumor cerebri, and aseptic meningitis, induced by various factors, may result from their interference with IDO and inducible nitric oxide synthase activities, endogenous NO level, and cytokine irregularities which finally affect former T. gondii status 2mo in the brain. All these biochemical disturbances caused by the CNS T. gondii infection/inflammation may also be responsible for the relationship found between neurologic symptoms, such as headache, vertigo, and syncope observed in apparently immunocompetent children and adolescents, and physical and psychiatric symptoms in adulthood. We therefore believe that tests for T. gondii should be performed obligatorily in apparently immunocompetent patients with different types of headaches, even if they have no enlarged peripheral lymph nodes. This may help to avoid overlooking this treatable cause of the CNS disease, markedly reduce costs of hospitalization, diagnosis and treatment, and eventually prevent developing serious neurologic and psychiatric disorders.
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Affiliation(s)
- Joseph Prandota
- Faculty of Medicine and Dentistry, University Medical School, Wroclaw, Poland.
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El-Mas MM, Zhang J, Abdel-Rahman AA. Upregulation of vascular inducible nitric oxide synthase mediates the hypotensive effect of ethanol in conscious female rats. J Appl Physiol (1985) 2005; 100:1011-8. [PMID: 16293701 DOI: 10.1152/japplphysiol.01058.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous reports from our laboratory have shown that ethanol elicits hypotension in female but not in male rats and that this effect of ethanol is estrogen dependent (El-Mass MM and Abdel-Rahman AA. Alcohol Clin Exp Res 23: 624-632, 1999; El-Mass MM and Abdel-Rahman AA. Clin Exp Hypertens 21: 1429-1445, 1999). In the present study, we tested the hypothesis that ethanol lowers blood pressure in female rats via upregulation of the inducible nitric oxide synthase (iNOS) in vascular tissues. The effects of pretreatment with NG-nitro-L-arginine (NOARG; nonselective nitric oxide synthase inhibitor) or aminoguanidine (selective iNOS inhibitor) on hemodynamic responses elicited by intragastric (ig) ethanol were determined in conscious female rats. Changes in vascular (aortic) iNOS protein expression evoked by ethanol in the presence and absence of aminoguanidine were also measured by immunohistochemistry. Compared with control (water treated) female rats, ethanol (1 g/kg ig) elicited hypotension that was associated with a significant increase in the aortic iNOS activity. The hypotensive effect of ethanol was virtually abolished in rats infused with the nitric oxide synthase inhibitor NOARG, suggesting a role for nitric oxide in ethanol hypotension. The inability of ethanol to lower blood pressure in NOARG-treated rats cannot be attributed to the presence of elevated blood pressure in these rats because ethanol produced hypotension when blood pressure was raised to comparable levels with phenylephrine infusion. Selective inhibition of iNOS by aminoguanidine (45 mg/kg ip), which had no effect on baseline blood pressure, abolished both the hypotensive action of subsequently administered ethanol and the associated increases in aortic iNOS content. These findings implicate vascular iNOS, at least partly, in the acute hypotensive action of ethanol in female rats.
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Affiliation(s)
- Mahmoud M El-Mas
- Dept. of Pharmacology, School of Medicine, East Carolina Univ., Greenville, NC 27858, USA
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Seo DO, Lee S, Rivier C. Prolonged exposure to intermittent alcohol vapors decreases the ACTH as well as hypothalamic nitric oxide and cytokine responses to endotoxemia. Alcohol Clin Exp Res 2004; 28:848-54. [PMID: 15201627 DOI: 10.1097/01.alc.0000128230.82909.a5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Prolonged exposure to alcohol blunts the response of the hypothalamic-pituitary-adrenal (HPA) axis to various stressors, including the systemic injection of a lipopolysaccharide (LPS). We previously showed that decreased synthesis of the hypothalamic peptides corticotropin-releasing factor (CRF) and vasopressin (VP) played a central role in this phenomenon. However, the mechanisms that lead to decreased hypothalamic neuronal activity have not been identified. In the present work, we tested the hypothesis that alcohol decreased signals that are elicited by LPS and that stimulate hypothalamic CRF and VP synthesis, namely nitric oxide (NO) and the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). METHODS Adult male rats were exposed to intermittent (5 hr/day) alcohol vapors for 5 days. Control animals were kept in comparable chambers but not exposed to the vapors. On day 6, the animals received an injection of LPS through permanent indwelling intravenous cannulae. The dependent variables were plasma ACTH levels measured by IRMA (immunoradiometric assay); pituitary and hypothalamic TNF-alpha and IL-6 mRNA levels measured by RNase protection assay; basal activity of neuronal NO synthase measured by conversion of [14C]arginine to [14C]citrulline, the constitutive enzyme that synthesizes NO and modulates the influence of this gas on LPS-induced HPA axis activity; and basal and LPS-induced levels of citrulline (an index of NO formation) in the hypothalamus, measured by immunocytochemistry. RESULTS After injection with LPS, rats that were pretreated with alcohol exhibited a significantly (p < 0.01) decreased release of ACTH, compared with controls. There was no difference in basal NO synthase activity or hypothalamic citrulline levels. In contrast, LPS-induced hypothalamic citrulline levels were significantly (p < 0.01) lower in alcohol-exposed rats, as were pituitary TNF-alpha and IL-6 transcripts. In the hypothalamus, the TNF-alpha but not IL-6 response to LPS was also reduced. CONCLUSIONS These results indicate that prolonged exposure to alcohol decreases the ACTH, hypothalamic NO and TNF-alpha, and pituitary TNF-alpha and IL-6 responses to LPS. This suggests that altered NO and proinflammatory cytokine levels in the brain may modulate the inhibitory influence exerted by alcohol on the HPA axis response to endotoxemia.
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Affiliation(s)
- Dong O Seo
- Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, 10010 N. Torrey Pines Road, La Jolla, California 92037, USA
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Davis RL, Syapin PJ. Acute ethanol exposure modulates expression of inducible nitric-oxide synthase in human astroglia: evidence for a transcriptional mechanism. Alcohol 2004; 32:195-202. [PMID: 15282113 DOI: 10.1016/j.alcohol.2004.01.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2003] [Revised: 01/10/2004] [Accepted: 01/11/2004] [Indexed: 10/26/2022]
Abstract
Astroglia are important in immunocompetence and response to injury within the CNS. Activated astroglia respond, in part, by expressing inducible nitric-oxide synthase (iNOS) and subsequent catalytic production of nitric oxide. Results from a previous study in our laboratory, in the human A172 astroglial cell line, revealed that induction of iNOS activity by tumor necrosis factor-alpha + interferon-gamma + interleukin-1 beta was inhibited by 24-h exposure to a high ethanol concentration (200 mM), but enhanced by 50 mM ethanol. In the work reported in this article, we tested the working hypothesis that ethanol acts transcriptionally to modulate cytokine-induced expression of the iNOS gene, NOS2A, in human astroglia. Ethanol, 50 or 200 mM, did not directly alter in vitro catalytic activity of the iNOS enzyme, indicating that ethanol does not affect the enzyme directly. Likewise, ethanol exposure after a 12-h cytokine-stimulation period had no effect on in vivo iNOS activity. However, when cells were simultaneously exposed to ethanol and cytokines for 12 h, in vivo iNOS activity was altered. That ethanol must be present during cytokine stimulation to influence iNOS activity is consistent with a transcriptional mechanism of action. In addition, steady-state expression of iNOS protein and NOS2A mRNA levels were modulated in a biphasic manner by ethanol similar to that noted previously for iNOS activity. These findings strongly support the suggestion that ethanol modulates cytokine-induced iNOS expression in A172 cells at a pretranslational site. These findings should be instrumental in the identification of the critical ethanol-sensitive elements involved in the regulation of NOS2A in human astroglia.
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Affiliation(s)
- Randall L Davis
- Alcohol and Brain Research Laboratory, Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430-0001, USA.
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Ayub S, Verma J, Das N. Effect of endosulfan and malathion on lipid peroxidation, nitrite and TNF-alpha release by rat peritoneal macrophages. Int Immunopharmacol 2003; 3:1819-28. [PMID: 14636831 DOI: 10.1016/j.intimp.2003.08.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Endosulfan and malathion are organochlorine and organophosphate insecticides, respectively. The toxicity of both the insecticides are well known on non-target organisms. Both endosulfan and malathion are reported to suppress humoral as well as cellular immune responses. We investigated the possible effect of both these insecticides on lipid peroxidation, nitrite production and TNF-alpha generation in rat peritoneal macrophages under in vitro conditions. Rat peritoneal cells were collected and cultured with or without insecticides and relevant stimulants for lipid peroxidation, generation of nitric oxide and TNF-alpha. FeSO(4) was used as an inducer for lipid peroxidation and LPS was used to induce nitric oxide synthase and release of TNF-alpha. Lipid peroxidation was assayed by estimating MDA; nitric oxide was determined by estimating nitrite and TNF-alpha by using an assay kit in culture supernatants. Both endosulfan and malathion had no effect on lipid peroxidation. Endosulfan did not have any influence on nitrite production, but suppressed the LPS-induced TNF-alpha generation. Malathion, however, showed a direct suppression on nitrite production and suppression of LPS-induced TNF-alpha generation. This study suggests that functional aberrations of macrophages may contribute significantly to the immunomodulation reported for these insecticides.
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Affiliation(s)
- Sadia Ayub
- Department of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
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Davis RL, Dertien J, Syapin PJ. Ethanol-Induced Modulation of Inducible Nitric-Oxide Synthase Activity in Human A172 Astrocytoma Cells. Alcohol Clin Exp Res 2002. [DOI: 10.1111/j.1530-0277.2002.tb02685.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Martin S, Diebolt M, Andriantsitohaina R. [Moderate alcohol consumption and cardiovascular diseases]. PATHOLOGIE-BIOLOGIE 2001; 49:769-74. [PMID: 11762141 DOI: 10.1016/s0369-8114(01)00241-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
While excessive ethanol consumption can result in higher rate of morbidity and mortality resulting from several diseases including cancer and cirrhosis, epidemiological studies suggest that moderate alcohol ingestion reduces the risk of cardiovascular diseases. However, the precise mechanisms by which moderate alcohol consumption protects against coronary heart disease (CHD) is not fully understood. Epidemiological studies suggest that alcohol consumption influences several risk factors for CHD including blood pressure, plasma cholesterol levels, platelet function, and fibrinolytic parameters, preventing both vascular thrombosis and occlusion. Turning to molecular and cellular levels, ethanol has been shown to act on several signal transduction mechanisms involve in the inhibition of smooth muscle cells proliferation and migration and in the activation of the release of vasoactive factors from vascular cells such as nitric oxide (NO). The latter is of importance since NO has been shown to possess antioxidant, antiaggregant properties, to regulate vascular tone and to inhibit both proliferation of smooth muscle cells and adhesion of leukocytes. Altogether, the above mentioned beneficial properties of moderate concentration of ethanol might help to explain the cardio- and vascular protection induced by ethanol. This review compels several bibliographic data concerning the cardiovascular effect of moderate alcohol consumption.
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Affiliation(s)
- S Martin
- Pharmacologie et physicochimie des interactions cellulaires et moléculaires, UMR CNRS 7034, université Louis Pasteur, faculté de pharmacie, BP 24, 67401 Illkirch, France
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Shih CL, Chi SI, Chiu TH, Sun GY, Lin TN. Ethanol Effects on Nitric Oxide Production in Cerebral Pial Cultures. Alcohol Clin Exp Res 2001. [DOI: 10.1111/j.1530-0277.2001.tb02258.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
There is strong evidence showing that chronic and excessive ethanol consumption may enhance oxidative damage to neurons and result in cell death. Although not yet well understood, ethanol may enhance ROS production in brain through a number of pathways including increased generation of hydroxyethyl radicals, induction of CYP2E1, alteration of the cytokine signaling pathways for induction of iNOS and sPLA(2), and production of prostanoids through the PLA(2)/COX pathways. Since many neurodegenerative diseases are also associated with oxidative and inflammatory mechanisms in the brain, it would be important to find out whether chronic and excessive ethanol consumption may exacerbate the progression of these diseases. There is evidence that the polyphenolic antioxidants, especially those extracted from grape skin and seed, may protect the brain from neuronal damage due to chronic ethanol administration. Among the polyphenols from grapes, resveratrol seems to have unique antioxidant properties. The possible use of this compound as a therapeutic agent to ameliorate neurodegenerative processes should be further explored.
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Affiliation(s)
- A Y Sun
- Department of Pharmacology, University of Missouri, Columbia, MO 65212, USA.
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Wang JH, Sun GY. Ethanol inhibits cytokine-induced iNOS and sPLA2 in immortalized astrocytes: evidence for posttranscriptional site of ethanol action. J Biomed Sci 2001; 8:126-33. [PMID: 11173986 DOI: 10.1007/bf02255981] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Chronic and excessive ethanol consumption is known to alter neuron and glial cell functions in the central nervous system (CNS). Astrocytes comprise the major cell type in the brain. These immune active cells are capable of responding to proinflammatory cytokines and endotoxins, which stimulate transcriptional pathways leading to induction of genes, including the inducible nitric oxide synthase (iNOS) and secretory phospholipase A2 (sPLA2). In this study, we investigate the effects of ethanol on cytokine-induced iNOS and sPLA2 in immortalized astrocytes (DITNC). When DITNC cells were exposed to ethanol (0-200 mM) for 4 h prior to subsequent stimulation with cytokines for 16 h, NO production decreased with increasing ethanol concentrations starting from 50 mM. At ethanol concentrations higher than 100 mM, ethanol also inhibited cytokine-induced sPLA2 release into the culture medium. The inhibitory effect of ethanol on NO production corresponds well with the decrease in iNOS protein and NOS enzyme activity, but not with iNOS and sPLA2 mRNA nor binding of NF-kappaB to DNA. The inhibition of cytokine-induced NO production by ethanol was also dependent on the time of ethanol exposure to the cells, but addition of acetaldehyde up to 200 microM did not elicit any changes. Taken together, these results provide evidence for a posttranscriptional mode of ethanol action on the cytokine induction pathway for NO production in astrocytes.
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Affiliation(s)
- J H Wang
- Department of Nutritional Sciences, University of Missouri, Columbia, MO 65212, USA
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Berger K, Ajani UA, Kase CS, Gaziano JM, Buring JE, Glynn RJ, Hennekens CH. Light-to-moderate alcohol consumption and the risk of stroke among U.S. male physicians. N Engl J Med 1999; 341:1557-64. [PMID: 10564684 DOI: 10.1056/nejm199911183412101] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Several studies have shown U- or J-shaped relations between alcohol consumption and the risk of stroke. We evaluated the effect of light-to-moderate alcohol intake on the risk of stroke, with separate analyses of ischemic stroke and hemorrhagic stroke. METHODS Our analyses were based on a prospective cohort study of 22,071 male physicians, 40 to 84 years old, who were participating in the Physicians' Health Study. At base line, the participants reported that they had no history of stroke, transient ischemic attack, or myocardial infarction and were free of cancer. Alcohol intake, reported by 21,870 participants at base line, ranged from none or almost none to two or more drinks per day. RESULTS During an average of 12.2 years of follow-up, 679 strokes were reported. As compared with participants who had less than one drink per week, those who drank more had a reduced overall risk of stroke (relative risk, 0.79; 95 percent confidence interval, 0.66 to 0.94) and a reduced risk of ischemic stroke (relative risk, 0.77; 95 percent confidence interval, 0.63 to 0.94). There was no statistically significant association between alcohol consumption and hemorrhagic stroke. The overall relative risks of stroke for the men who had one drink per week, two to four drinks per week, five or six drinks per week, or one or more drinks per day were 0.78 (95 percent confidence interval, 0.59 to 1.04), 0.75 (95 percent confidence interval, 0.58 to 0.96), 0.83 (95 percent confidence interval, 0.62 to 1.11), and 0.80 (95 percent confidence interval, 0.64 to 0.99), respectively, in an analysis in which we controlled for major risk factors for stroke. CONCLUSIONS Light-to-moderate alcohol consumption reduced the overall risk of stroke and the risk of ischemic stroke in men. The benefit is apparent with as little as one drink per week. Greater consumption, up to one drink per day, does not increase the observed benefit.
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Affiliation(s)
- K Berger
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02215, USA
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Affiliation(s)
- R Wolf
- Department of Dermatology, Tel-Aviv Sourasky Medical Center, Ichilov Hospital, Israel
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Wang E, Spitzer JJ, Chamulitrat W. Differential regulation of inducible nitric oxide synthase gene expression by ethanol in the human intestinal epithelial cell line DLD-1. Nitric Oxide 1999; 3:244-53. [PMID: 10442856 DOI: 10.1006/niox.1999.0230] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have examined the regulation of inducible nitric oxide synthase (iNOS) gene expression by ethanol in monolayers of DLD-1 cells, an epithelial cell line derived from human intestinal adenocarcinoma. Optimum induction of iNOS mRNA in these cells was obtained with IFN-gamma and IL-1beta treatment, while further addition of TNF-alpha did not have significant effect. In a set of experiments to study ethanol effects, DLD-1 monolayers were pretreated with ethanol for 24 h and were then treated with IFN-gamma + IL-1beta for an additional 24 h. Cells pretreated with ethanol showed decreased iNOS mRNA levels, indicating that ethanol may inhibit cytokine-induced iNOS transcription or affect mRNA destabilization. The suppression was ethanol-dose dependent with an IC50 of 50 mM. In another set of experiments to study ethanol effects, DLD-1 monolayers were pretreated with 66 mM ethanol for 24 h. These cells showed significant upregulation of IL-1beta mRNA and protein as detected in the supernatants. Aliquoted supernatants from these cells (i.e., conditioned media) were added to naive DLD-1 monolayers together with IFN-gamma. Conditioned medium from ethanol-treated cells increased the IFN-gamma-induced iNOS mRNA of naive cells by threefold. Two different effects of ethanol are now reported: (a) ethanol inhibits IFN-gamma + IL-1beta-induced iNOS mRNA of the same DLD-1 cells and (b) ethanol induces cellular paracrine signals by releasing IL-1beta into the medium, which in combination with IFN-gamma increases iNOS mRNA levels of the recipient naive DLD-1 cells. Because IFN-gamma and IL-1beta are produced by intestinal immune cells, these findings may have implications for differential in vivo regulation of epithelial iNOS genes by ethanol, depending on the inflammatory and immune status of the host.
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Affiliation(s)
- E Wang
- Department of Physiology and Alcohol Research Center, Louisiana State University Medical Center, New Orleans 70112-1393, USA
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Greenberg SS, Xie J, Ouyang J, Zhao X. Ethanol metabolism is not required for inhibition of LPS-stimulated transcription of inducible nitric oxide synthase. Alcohol 1999; 17:203-13. [PMID: 10231168 DOI: 10.1016/s0741-8329(98)00048-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We examined the effect of inhibition of ethanol metabolism on ethanol-mediated suppression of Escherichia coli endotoxin (LPS-induced upregulation of transcription and release of inducible nitric oxide synthase (iNOS) and tumor necrosis factor alpha (TNFalpha) from rat alveolar macrophages (AM) in vivo. Ethanol (3.45 and 5.5 g/kg/IP) and t-butanol (3.7 g/kg, IP), given 30 min before intratracheal administration of LPS (1.0 mg/kg), inhibited the upregulation of iNOS mRNA and protein, determined by competitor equalized RT-PCR and Western immunoblot, respectively, but not TNFalpha mRNA in AM obtained 2 h after LPS administration by bronchoalveolar lavage (BAL). However, ethanol and t-butanol inhibited LPS-stimulated nitrate and nitrite (RNI) and TNFalpha protein in BAL fluid. Pretreatment of rats with 4-methylpyrazole (100 mg/kg, IP) 2 h before, or disulfiram 30 min before, administration of ethanol (3.45 g/kg, IP) failed to attenuate the inhibitory effect on iNOS mRNA or protein. t-Butyl hydroperoxide (100 mg/kg, IP) given to rats 30 min before administration of LPS enhanced LPS-mediated upregulation of iNOS mRNA and TNFalpha protein in AM and BAL fluid. The inhibitory effect of ethanol on iNOS mRNA was not mediated by an interaction with elevated levels of circulating corticosterone because pretreatment of rats with RU-38486 (100 mg/kg, IM), which inhibited prednisolone (50 mg/kg, IM), induced suppression of LPS-stimulated iNOS mRNA, and failed to attenuate ethanol-mediated inhibition of LPS-stimulated iNOS mRNA in AM. We conclude that metabolism of ethanol to acetaldehyde via alcohol dehydrogenase is not required for ethanol-mediated suppression of LPS-induced iNOS transcription and TNFalpha synthesis/release in AM. Moreover, an interaction of ethanol or acetaldehyde with circulating corticosterone is not involved in ethanol-mediated attenuation of LPS-stimulated iNOS mRNA or protein or TNFalpha protein in the lung. Speculatively, because oxidation of t-butanol to t-butylhydroperoxide results in activation, rather than inhibition, of iNOS and TNF-alpha, the reported ethanol-mediated enhancement of iNOS mRNA may result from the action of the hydroxyethyl radical.
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Affiliation(s)
- S S Greenberg
- Department of Medicine, The Alcohol Research Center, Louisiana State University Medical Center, New Orleans 70112, USA.
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18
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Syapin PJ, Rendon A, Huron DR, Militante JD. Effects of short chain alkanols on the inducible nitric oxide synthase in a glial cell line. Br J Pharmacol 1999; 126:1253-61. [PMID: 10205016 PMCID: PMC1565888 DOI: 10.1038/sj.bjp.0702417] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Ethanol inhibits inducible nitric oxide synthase (iNOS) expression in C6 glioma cells by an unknown mechanism. Because relatively high concentrations are needed for inhibition in drug-naive cells (IC50 approximately = to 150 mM), suppression due to cytotoxicity is one possible mechanism that has not been ruled out. Therefore, the present study examined the effects of ethanol and other alkanols on C6 glioma cell viability and iNOS activity to better understand the mechanism for inhibition. 2. iNOS expression was induced in cell culture with lipopolysaccharide and phorbol ester treatment. Nitrite accumulation in culture medium, the in vitro conversion of [3H]-L-arginine to [3H]-L-citrulline, and immunoblotting were used to quantify iNOS induction and activity. Trypan blue exclusion, extracellular release of lactate dehydrogenase, and quantity of total cell protein were used as measures of viability. 3. Short chain alkanols, methanol through 1-heptanol, concentration-dependently inhibited nitrite accumulation. Longer chain alkanols, 1-octanol and 1-decanol, did not except at cytotoxic concentrations. Experiments indicated short chain alkanol inhibition was not due to direct actions on iNOS catalytic activity, but that it transpires during iNOS induction. Immunoblots showed reduced iNOS protein levels. 4. Correlation analysis ruled out iNOS inhibition as being due to decreased cell number, total cell protein, or cell viability. In contrast, there was significant correlation with physical measures of lipophilicity. 5. In conclusion, inhibition of iNOS expression by ethanol and other short chain alkanols is not due to cytotoxicity. Instead, the strong correlation with lipophilicity suggests the inhibition derives from an interaction with unknown hydrophobic cellular sites.
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Affiliation(s)
- P J Syapin
- Department of Pharmacology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock 79430, USA.
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19
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Wang JY, Wang JY, Wang JY, Shum AY, Hwang CP. Ethanol modulates induction of nitric oxide synthase in glial cells by endotoxin. Life Sci 1998; 63:1571-83. [PMID: 9808068 DOI: 10.1016/s0024-3205(98)00424-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Although ethanol has long been recognized as an immunosuppressant, the effects of ethanol on immune functions in the central nervous system (CNS) have not been well characterized. Glial cells function as immune effector cells within the CNS. Nitric oxide (NO), generated by inducible NO synthase (iNOS) of activated glial cells, appears to participate in the immune defense and the pathogenesis of brain injury and several neurologic diseases. The goal of the present study was to examine the effects of ethanol on NO production and mRNA expression of iNOS following its induction by bacterial endotoxin lipopolysaccharide (LPS) in cultured glial cells. After incubation of mixed glia with LPS for 24 hr, the levels of nitrite in the culture medium were assayed by Griess reaction. We found that LPS (10-500 ng/ml) induced a concentration-dependent increase in the production of NO which was abolished by the selective iNOS inhibitor aminoguanidine. While ethanol treatment (25 to 400 mM, 24 hr exposure) had no direct effect on basal NO production, it significantly suppressed the LPS-induced increase of nitrite levels in a concentration-dependent manner. Using a semiquantitative reverse transcriptase polymerase chain reaction, we found that while ethanol by itself was unable to induce iNOS mRNA, it nevertheless suppressed LPS-induced iNOS mRNA expression. Our results that ethanol had no direct effect on NO production but inhibited LPS-induced NO, indicated an immunomodulatory role by ethanol. These findings suggest that ethanol may ameliorate the consequences of overwhelming NO generation through iNOS induction in glial cells following infection, inflammation or CNS injuries.
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Affiliation(s)
- J Y Wang
- Department of Physiology, National Defense Medical Center, Taipei, Taiwan, ROC.
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20
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Abstract
The L-arginine-nitric oxide pathway is important to both physiological and pathologic brain events. Brain tissue contains cells able to express all known isoforms of nitric oxide synthase, the rate-limiting enzyme in nitric oxide (NO) production and release. Effects of ethanol on NO production may be important to ethanol modification of brain function. Recent studies support this idea and demonstrate diverse interactions. For example, acute ethanol treatment decreases NMDA- and cytokine-stimulated NO synthesis by cortical neurons and glia, respectively, but enhances cytokine-stimulated NO synthesis in blood-brain barrier endothelial cells and does not affect norepinephrine-stimulated NO synthesis in medial basal hypothalamus. Furthermore, chronic ethanol enhances NMDA-stimulated NO synthesis in cortical neurons, but more potently decreases cytokine-induced NO synthesis in glial cells. The mechanisms underlying these effects are partially understood and include changes in NOS-2 gene expression. These observations illustrate that ethanol selectively affects NO production by brain cells, which may relate to reported behavioral interactions, but the extend and direction of change depends on cell type and length of exposure.
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Affiliation(s)
- P J Syapin
- Department of Pharmacology, Texas Tech University Health Sciences Center, Lubbock 79430-0001, USA
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21
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Gottesfeld Z, Maier M, Mailman D, Lai M, Weisbrodt NW. Splenic sympathetic response to endotoxin is blunted in the fetal alcohol-exposed rat: role of nitric oxide. Alcohol 1998; 16:19-24. [PMID: 9650632 DOI: 10.1016/s0741-8329(98)00009-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
This study was designed to test the hypothesis that nitric oxide (NO) mediates the blunted splenic sympathetic response to lipopolysaccharide (endotoxin) that occurs in young rats exposed to alcohol in utero (FAE). The subjects, 26-29-day-old rats, were progeny of pregnant dams fed an alcohol diet (35% of the calories were derived from ethanol) or their control and pair-fed (PFC) cohorts. We examined the effects of lipopolysaccharide (LPS) (0.5 mg/kg, i.p.) on splenic norepinephrine (NE) turnover, an index of sympathetic neural activity, splenic inducible NO synthase (iNOS) protein immunoreactivity, and NO metabolites nitrite/nitrate concentrations in plasma. In response to LPS, splenic NE turnover was increased by more than twofold in the PFC groups, but the increase did not occur in their FAE cohorts. The blockade of NOS with L-NAME (30 mg/kg, i.p.) reversed this difference. In both the PFC and FAE rats, basal levels of splenic iNOS protein immunoreactivity were equally barely detected and plasma NO metabolite levels were relatively low (25 microM in both groups). In response to LPS, however, iNOS protein displayed a marked increase in the PFC group and an even greater increase (by close to threefold) in the FAE rats. LPS also substantially increased plasma NO metabolite levels by close to eightfold in the control groups, but by 15-fold in their FAE cohorts compared to the basal levels. These findings support the hypothesis that in the FAE rat, an augmented NO formation accounts for the blunted sympathetic response to endotoxin.
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Affiliation(s)
- Z Gottesfeld
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston 77225, USA.
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22
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Durante W, Liao L, Peyton KJ, Schafer AI. Lysophosphatidylcholine regulates cationic amino acid transport and metabolism in vascular smooth muscle cells. Role in polyamine biosynthesis. J Biol Chem 1997; 272:30154-9. [PMID: 9374496 DOI: 10.1074/jbc.272.48.30154] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Lysophosphatidylcholine (lyso-PC) is a major component of atherogenic lipids that stimulate vascular smooth muscle cell (SMC) proliferation. Because cationic amino acids are metabolized to growth-stimulatory polyamines, we examined whether lyso-PC regulates the transcellular transport and metabolism of cationic amino acids by vascular SMC. Treatment of SMC with lyso-PC initially (0-2 h) decreased cationic amino acid uptake, whereas longer exposures (6-24 h) progressively increased transport. Kinetic studies indicated that lyso-PC-induced inhibition was associated with a decrease in affinity for cationic amino acids, but the stimulation was mediated by an increase in transport capacity. Lyso-PC strongly induced the expression of cationic amino acid transporter-2 mRNA while modestly elevating the level of cationic amino acid transporter-1 mRNA. In addition, lyso-PC stimulated intracellular cationic amino acid metabolism by inducing ornithine decarboxylase activity and mRNA expression and also by inducing arginase activity in vascular SMC. In contrast, lyso-PC inhibited the catabolism of L-arginine to nitric oxide by blocking inducible nitric oxide synthase expression. Lyso-PC increased markedly the capacity of SMC to generate putrescine, a polyamine, from extracellular L-ornithine and L-arginine. The lyso-PC-mediated increase in the production of putrescine was reversed by NG-methyl-L-arginine, a competitive inhibitor of cationic amino acid transport, or by alpha-difluoromethylornithine, an ornithine decarboxylase inhibitor. The formation of putrescine from L-arginine was also prevented by arginase inhibitor NG-hydroxy-L-arginine. These results demonstrate that lyso-PC stimulates polyamine synthesis in vascular SMC by inducing the expression of the genes that regulate both the transport and metabolism of cationic amino acids. The actions of lyso-PC in stimulating cationic amino acid uptake and directing their metabolism to growth-stimulatory polyamines while simultaneously inhibiting the synthesis of antiproliferative NO, may contribute to lyso-PC-induced SMC proliferation and atherosclerotic lesion formation.
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Affiliation(s)
- W Durante
- Houston Veterans Administration Medical Center and the Departments of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA
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23
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Ehrenreich H, Schuck J, Stender N, Pilz J, Gefeller O, Schilling L, Poser W, Kaw S. Endocrine and Hemodynamic Effects of Stress Versus Systemic CRF in Alcoholics during Early and Medium Term Abstinence. Alcohol Clin Exp Res 1997. [DOI: 10.1111/j.1530-0277.1997.tb04450.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zhao X, Jie O, Li H, Xie J, Giles TD, Greenberg SS. Ethanol Inhibits Inducible Nitric Oxide Synthese Transcription and Post-Transcriptional Processes in Vivo. Alcohol Clin Exp Res 1997. [DOI: 10.1111/j.1530-0277.1997.tb04445.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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Abstract
Experimental and clinical data pertaining to alcohol (ethanol, EtOH) interference with cytokine networks are analyzed from the viewpoint of their importance for understanding the deleterious effects of EtOH on various functions. The data are grouped and analysed according to several major directions that have emerged in the last decade since the research on EtOH interference with cytokine networks started. These are: cytokine secretion, including the effects of the drug on in vivo cytokine levels and on in vitro cytokine secretion by various cells; cytokine-receptor interaction; intracellular fate of cytokines; and cellular responses to cytokines. Correspondingly, the data are presented in four tables. Attention is paid to the fact that the effects of EtOH on various aspects of cytokine biology (e.g., secretion by various cells) are diversified. Contradictory data have been reported but the cause for discrepancy is poorly understood. EtOH effects vary with the cytokine studied, the method of EtOH administration (i.e., acute or chronic), the species used, or with other experimental conditions. It is important to note, however, that the vast majority of experimental and clinical data show that EtOH interferes with cytokine networks and that research on such interference may lead to important steps in understanding the mechanisms of action of EtOH. An attempt is made herein to select aspects of cytokine biology, as affected by EtOH, that have been studied to a lesser extent, thus calling for more research efforts in those areas.
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Affiliation(s)
- I V Deaciuc
- University of Kentucky, Chandler Medical Center, College of Medicine, Department of Medicine, Gastroenterology, Lexington 40536, USA
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26
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Abstract
The epithelia of the respiratory tract are protected by a mucin glycoprotein. The expression of mucin changes when epithelia come in contact with toxic agents such as ethanol. Previously, we have identified and characterized the expression of a tracheo-bronchial mucin (TBM) gene. In the present study, we observed that ethanol regulates TBM expression at the transcription level. Ethanol enhanced the expression of TBM mRNA in a dose- and time-dependent manner in HBE1 cells. At 100 mM concentration (a concentration reported to be present in alcoholics), ethanol induced an eight-fold increase in TBM transcription as determined by reporter gene expression analysis.
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Affiliation(s)
- M Verma
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, DC 20007, USA.
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27
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Naassila M, Roux F, Beaugé F, Daoust M. Ethanol potentiates lipopolysaccharide- or interleukin-1 beta-induced nitric oxide generation in RBE4 cells. Eur J Pharmacol 1996; 313:273-7. [PMID: 8911924 DOI: 10.1016/0014-2999(96)00643-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Our present study investigated the effects of ethanol treatment on inducible nitric oxide (NO) synthase pathway from lipopolysaccharide- or interleukin-1 beta-treated cultured rat blood-brain barrier cell line (rat brain endothelial 4 cells: RBE4 cells). Cells were lipopolysaccharide- or interleukin-1 beta-treated with or without ethanol (50, 100 or 200 mM) for 16 or 24 h. Inducible NO synthase activity and mRNA expression were measured using Griess reaction and reverse transcription-polymerase chain reaction (RT-PCR) respectively. In the absence of lipopolysaccharide or interleukin-1 beta, ethanol treatments failed to stimulate inducible NO synthase gene expression. Lipopolysaccharide or interleukin-1 beta increased nitrite production and inducible NO synthase mRNA levels, and ethanol potentiated this effect. We concluded that ethanol could aggravate the consequences of NO generation by RBE4 cells after inducible NO synthase induction following inflammation or sepsis. This ethanol action on NO generation could contribute to circulatory failure associated with shock due to sepsis or hemorrhage, and alter blood-brain barrier permeability.
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Affiliation(s)
- M Naassila
- INSERM U295, Université de Médecine Pharmacie, Rouvray, France
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28
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Durante W, Liao L, Iftikhar I, O'Brien WE, Schafer AI. Differential regulation of L-arginine transport and nitric oxide production by vascular smooth muscle and endothelium. Circ Res 1996; 78:1075-82. [PMID: 8635238 DOI: 10.1161/01.res.78.6.1075] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Since NO production is dependent on the availability of L-arginie, we examined whether L-arginine transport and NO synthesis are coregulated by vascular smooth muscle cells and endothelial cells cultured from the same vessel wall source. L-Arginine transport by both bovine aortic smooth muscle cells (BASMCs) and endothelial cells (BAECs) was primarily Na+ independent (approximately 70%) and was mediated by both a high- and low-affinity transport system. Treatment of BASMCs with tumor necrosis factor-alpha (TNF-alpha) or interleukin-1 beta (IL-1 beta) resulted in a significant increase in L-arginine transport (approximately 20%) and in the induction of NO release. Exposure of BASMCs to interferon gamma (IFN-gamma) or lipopolysaccharide (LPS) also stimulated NO release but did not affect L-arginine transport. In contrast, incubation of BAECs with TNF-alpha or LPS strikingly enhanced L-arginine uptake (2.5-fold), whereas IL-1 beta and IFN-gamma had no effect. Treatment of BAECs with any of the inflammatory mediators did not stimulate NO production. These results demonstrate that L-arginine uptake and NO synthesis by these cells are differentially regulated. In BASMCs, the coinduction of L-arginine transport and NO formation may function to provide increased levels of substrate to the cell during activation of the NO synthase enzyme. In contrast, the selective stimulation of L-arginine uptake in BAECs indicates that L-arginine transport is dissociated from NO generation in these cells.
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Affiliation(s)
- W Durante
- Houston VA Medical Center, TX 77030, USA
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29
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Durante W, Liao L, Iftikhar I, Cheng K, Schafer AI. Platelet-derived growth factor regulates vascular smooth muscle cell proliferation by inducing cationic amino acid transporter gene expression. J Biol Chem 1996; 271:11838-43. [PMID: 8662668 DOI: 10.1074/jbc.271.20.11838] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Since recent studies demonstrated that platelet-derived growth factor (PDGF) induces vascular smooth muscle cell (SMC) proliferation by stimulating polyamine synthesis, we examined whether the transcellular transport of L-ornithine, the cationic amino acid precursor of polyamines, could regulate the mitogenic response of PDGF. Treatment of SMC with PDGF stimulated DNA and putrescine synthesis, and this was enhanced further by increasing the extracellular concentration of L-ornithine. The potentiating effect of L-ornithine was reversed by the competitive inhibitor of cationic amino acid transport, methyl-L-arginine, or by preventing putrescine formation with alpha-difluoromethylornithine. Cationic amino acid uptake by SMC was Na+-independent and was mediated by both a high and low affinity carrier system. Treatment of SMC with PDGF initially (0-2 h) decreased basic amino acid transport, while longer exposures (6-24 h) progressively increased uptake. Kinetic studies indicated that PDGF-induced inhibition was associated with a decrease in affinity for cationic amino acids, while the stimulation was mediated by an increase in transport capacity. Endogenous PDGF released by collagen-activated platelets likewise up-regulated cationic amino acid transport in SMC. Reverse transcriptase-polymerase chain reaction detected the presence of mRNA encoding two distinct cationic amino acid transporter (CAT) proteins, CAT-1 and CAT-2B. Treatment of SMC with PDGF strongly induced the expression CAT-2B mRNA and modestly elevated the level of CAT-1 mRNA. These results demonstrate that PDGF-induced polyamine synthesis and SMC mitogenesis are dependent on the transcellular transport of L-ornithine. The capacity of PDGF to up-regulate the transport of L-ornithine by inducing the expression of the genes for CAT-1 and CAT-2B may modulate its mitogenic effect by providing SMC with the necessary intracellular precursor for polyamine biosynthesis.
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Affiliation(s)
- W Durante
- Houston Veterans Affairs Medical Center, Texas 77030, USA
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