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The role of vitamin E, C and β-carotene in the prevention of arteriosclerosis and cancer
THE ROLE OF VITAMIN E, C AND [PCAROTENE IN THE PREVENTION OF ARTERIOSCLEROSIS AND CANCER U. Moser, Hoffinann-La Roche Ltd, Dept. Human Nutrition Research, CH 4002 Basel
INFLUENCE OF REDOX STATUS ON HIV INFECTION N.r.J.SLa~, M.-A. Pocidalo and F. Aillet. Inslitut Pasteur 25-28 rue du Dr. Roux- 75015 Paris, ~CE
Nutritional habits influence the risk of becoming affected with a degenerative disease. Fruits and vegetables are considered to be protective and excessive fat consumption, especially saturated fatty acids, are linked to the course of cancer and cardiovascular events. Some of the Componentsthat are responsible for the health benefit could be identified during the last years by means of epidemiological studies. Examples for Cardiovascular diseases: The North - South gradient of the mortality ofischemic heart disease in Europe can be explained by combining the risk factors cholesterol, blood pressure and the dietary factors vitamin E, [3-carotene(BC) and vitamin C by up to 90%. In a case control study 110 men suffering from angina pectoris had remarkably lower vitamin C, E, A and BC plasma levels than 394 matched controls. Several prospective studies point to similar results: lower risks are linked to higher plasma levels. Examples for Cancer: Numerous prospective trials showed lower risks for cancer mortality of several sites in women and men with high plasma levels of BC, vitamin E and vitamin C. However, recent large intervention studies revealed a complex situation: Whereas in China the mortality of cancer, especially stomach cancer, could be significantly reduced with BC, Vitamin E plus Selenium, the opposite was true in Finland where no effect was observed by giving Vitamin E and/or BC or even an increase with BC. In a smaller study the recurrence rate of bladder tumor could be reduced by 50 % with high doses of Vitamin C, A, E, B6 and Zn. Conclusion: More information about the mechanistic involvement of nutrients in cell regulation will help us to understand their role in the prevention of diseases.
HIV responds to transcriptionnal stimuli similar to those leading to induction of cellular genes during T cell activation. The most relevant event is the activation of the transcription factor NF-~:B which binds to two specific sites constituing the HIV enhancer. We showed that peroxyl radical scavengers such as BHA (butylated hydroxyanisole) or Vitamin E (atocopherol) block the activation events and HIV enhancer activity in PMA- or TNF- stimulated T (J.Jhan) or monocylic (U937) cell lines. To evaluate the potential therapeutic valu e of antioxidants in the treatment of HIV infected patients, we examined in vitro the effects of BHA or NAC (N-acetyl cystein) a known glutathione precursor, in terms of both inhibition of HIV replication in monocytes and in terms of modulation of the immune competence as measured by PBMC proliferation. Both antioxidants block NF-~:B activity induced in latently infected monocytes (U1 cells) or permanent in productively and chronically infected U937. However, these antioxidant treatments resulted in only a partial inhibition of TNF- or PMA-induced replication in the latent system (U1) and no inhibition in the highly replicative system (chronically infected U937). Moreover, anti0xidant concentrations, high enough to block NF-~:B activity, were shown to have suppressive effect on immune functions in vitro since NAC and BHA blocked IL2-induced PBMC proliferation.
HEME OXYGENASE ACTIVATION BY NITRIC OXIDE PROTECTS ENDOTHELIAl, CELLS AGAINST OXIDATIVE STRESS° R. Motterlini~ R. Foresti, M. Intaglietta and ~R. M. Winslow. Department of Bioengineering and ~Department of Medicine, University of California San Diego, La Jolla, CA 92093
MOLECULAR ANALYSIS OF ANTHRACYCLINE TOXICITY IN HUMAN HEART _G_GiorgioMinotti Department of Pharmacology, Catholic University School of Medicine, Largo F. Vito, 1, 00168 Rome, Italy.
Nitric oxide (NO) is a signaling molecule which has been implicated in both cytotoxic and cytoprotective activities in several in vitro and in vivo systems. We investigated the effect of NO on the induction of the stress protein heine oxygenase and its protective role in vascular endothelial ceils prior exposure to hydrogen peroxide. Porcine aortic endothelial cells exposed for 6 h to the NO-releasing compounds (0.1-lmM) sodium nitropmsside (SNP), S-nitroso-Nacetyl-penicillamine (SNAP) and 3-Morpholinsydnonimine (SIN-I) resulted in a concentration-dependent increase in heine oxygenase activity~ At 1 mM, the activity of heine oxygenase augmented 8:5-t'old with SNP, 5.8-fold with SNAP and 5.7-fold with SIN-I over the control value. Activation of the inducible NO synthase by the synergistic action of bacterial lipopolys~/ccharide (LPS, 250 ng/ml) and intefferon-7 (IFN-7, 100 U/ml) also increased endothelial heme oxygenase activity by 3.2-fold (p<0.05 vs. control). Methylene blue (1 I~M), an inhibitor of both NO synthase and gnanylate cyclase activities, completely abolished this effect. Cells previously exposed to SNAP and SIN-I, exhibited a significant protection against the cytotoxicity mediated by hydrogen peroxide (250 #M) (p<0.05). Conversely, SNP did not show any protective effects, possibly because Of catalytic iron released during its chemical decomposition. In fact, the iron chelator deferoxamine (5 mM) completely suppressed the SNP-mediated cytotoxicity. These results indicate that NO, either by itself or through the action of an intracellular me~enger, is a determinant in the modulation of the activity of heme oxygenase leading to a major resistance of the endothelium to oxidative stress.
Iron- and oxyradical- dependent lipid peroxidation (LPO) has been implicated in the cardiotoxieity of doxorubicin (DOX) and other anticancer anthraeyclines, reportedly because the semiquinone metabolites of these drugs release Fe(II) from ferritin and reduce oxygen to 02- and H202. In contrast to this mechanism, we have found that an i.v. bolus of DOX (80-90 mg/m2) inhibits cardiac LPO in cancer patients, as evidenced b y a decrease of the coronary sinus/femoral artery gradient in hydroperoxy fatty acid cis-trans conjugated dienes (from 3.3+1.7 to 0.9_+0.3, n=6, P< 0.01). In this respect, we have in vitro data suggesting that LPO proceeds via the formation of H202/Fe(II) ratios < 0.5, hence, it cannot be promoted by anthracycline semiquinones which usually form H202 in excess of Fe(II). Subsequent studies with NADPH-supplemented drugmetabolizing cytosolic fractions from ex vivo and post mortem myocardial biopsies have shown that DOX is converted to a secondary alcohol. T h i s metabolite does not reduce oxygen, however, it releases Fe(II) from protein(s) that are physicochemically distinct from ferritin. Replacing DOX with less eardiotoxic dannorubicin (DNR), 4'-epi-DOX and 4-demethoxyDNR consistently decreases the yield of secondary alcohols [from 3.9+0.4 to 2.1_+0.1; 1.2!0.2; and 0.6_+0.2 nmol/mg prot./4h, respectively] and the release of Fe(II) [from 6. hk-0.4 to 3.5_+0.1; 1.8 _+0.2; and 0.9-2-0.3 nmol/mg prot./4h, respectively] (n--4, P< 0.01). Thus, secondary alcohol metabolites mediate the eardiotoxieity of anthracyclines, perhaps via free radical- and LPO- independent removal of iron from, and inactivation of, iron-requiring enzymes such as aconitase, ribonucleotide reductase, or others.
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INFLUENCE OF REDOX STATUS ON HIV INFECTION N.r.J.SLa~, M.-A. Pocidalo and F. Aillet. Inslitut Pasteur 25-28 rue du Dr. Roux- 75015 Paris, ~CE
Nutritional habits influence the risk of becoming affected with a degenerative disease. Fruits and vegetables are considered to be protective and excessive fat consumption, especially saturated fatty acids, are linked to the course of cancer and cardiovascular events. Some of the Componentsthat are responsible for the health benefit could be identified during the last years by means of epidemiological studies. Examples for Cardiovascular diseases: The North - South gradient of the mortality ofischemic heart disease in Europe can be explained by combining the risk factors cholesterol, blood pressure and the dietary factors vitamin E, [3-carotene(BC) and vitamin C by up to 90%. In a case control study 110 men suffering from angina pectoris had remarkably lower vitamin C, E, A and BC plasma levels than 394 matched controls. Several prospective studies point to similar results: lower risks are linked to higher plasma levels. Examples for Cancer: Numerous prospective trials showed lower risks for cancer mortality of several sites in women and men with high plasma levels of BC, vitamin E and vitamin C. However, recent large intervention studies revealed a complex situation: Whereas in China the mortality of cancer, especially stomach cancer, could be significantly reduced with BC, Vitamin E plus Selenium, the opposite was true in Finland where no effect was observed by giving Vitamin E and/or BC or even an increase with BC. In a smaller study the recurrence rate of bladder tumor could be reduced by 50 % with high doses of Vitamin C, A, E, B6 and Zn. Conclusion: More information about the mechanistic involvement of nutrients in cell regulation will help us to understand their role in the prevention of diseases.
HIV responds to transcriptionnal stimuli similar to those leading to induction of cellular genes during T cell activation. The most relevant event is the activation of the transcription factor NF-~:B which binds to two specific sites constituing the HIV enhancer. We showed that peroxyl radical scavengers such as BHA (butylated hydroxyanisole) or Vitamin E (atocopherol) block the activation events and HIV enhancer activity in PMA- or TNF- stimulated T (J.Jhan) or monocylic (U937) cell lines. To evaluate the potential therapeutic valu e of antioxidants in the treatment of HIV infected patients, we examined in vitro the effects of BHA or NAC (N-acetyl cystein) a known glutathione precursor, in terms of both inhibition of HIV replication in monocytes and in terms of modulation of the immune competence as measured by PBMC proliferation. Both antioxidants block NF-~:B activity induced in latently infected monocytes (U1 cells) or permanent in productively and chronically infected U937. However, these antioxidant treatments resulted in only a partial inhibition of TNF- or PMA-induced replication in the latent system (U1) and no inhibition in the highly replicative system (chronically infected U937). Moreover, anti0xidant concentrations, high enough to block NF-~:B activity, were shown to have suppressive effect on immune functions in vitro since NAC and BHA blocked IL2-induced PBMC proliferation.
HEME OXYGENASE ACTIVATION BY NITRIC OXIDE PROTECTS ENDOTHELIAl, CELLS AGAINST OXIDATIVE STRESS° R. Motterlini~ R. Foresti, M. Intaglietta and ~R. M. Winslow. Department of Bioengineering and ~Department of Medicine, University of California San Diego, La Jolla, CA 92093
MOLECULAR ANALYSIS OF ANTHRACYCLINE TOXICITY IN HUMAN HEART _G_GiorgioMinotti Department of Pharmacology, Catholic University School of Medicine, Largo F. Vito, 1, 00168 Rome, Italy.
Nitric oxide (NO) is a signaling molecule which has been implicated in both cytotoxic and cytoprotective activities in several in vitro and in vivo systems. We investigated the effect of NO on the induction of the stress protein heine oxygenase and its protective role in vascular endothelial ceils prior exposure to hydrogen peroxide. Porcine aortic endothelial cells exposed for 6 h to the NO-releasing compounds (0.1-lmM) sodium nitropmsside (SNP), S-nitroso-Nacetyl-penicillamine (SNAP) and 3-Morpholinsydnonimine (SIN-I) resulted in a concentration-dependent increase in heine oxygenase activity~ At 1 mM, the activity of heine oxygenase augmented 8:5-t'old with SNP, 5.8-fold with SNAP and 5.7-fold with SIN-I over the control value. Activation of the inducible NO synthase by the synergistic action of bacterial lipopolys~/ccharide (LPS, 250 ng/ml) and intefferon-7 (IFN-7, 100 U/ml) also increased endothelial heme oxygenase activity by 3.2-fold (p<0.05 vs. control). Methylene blue (1 I~M), an inhibitor of both NO synthase and gnanylate cyclase activities, completely abolished this effect. Cells previously exposed to SNAP and SIN-I, exhibited a significant protection against the cytotoxicity mediated by hydrogen peroxide (250 #M) (p<0.05). Conversely, SNP did not show any protective effects, possibly because Of catalytic iron released during its chemical decomposition. In fact, the iron chelator deferoxamine (5 mM) completely suppressed the SNP-mediated cytotoxicity. These results indicate that NO, either by itself or through the action of an intracellular me~enger, is a determinant in the modulation of the activity of heme oxygenase leading to a major resistance of the endothelium to oxidative stress.
Iron- and oxyradical- dependent lipid peroxidation (LPO) has been implicated in the cardiotoxieity of doxorubicin (DOX) and other anticancer anthraeyclines, reportedly because the semiquinone metabolites of these drugs release Fe(II) from ferritin and reduce oxygen to 02- and H202. In contrast to this mechanism, we have found that an i.v. bolus of DOX (80-90 mg/m2) inhibits cardiac LPO in cancer patients, as evidenced b y a decrease of the coronary sinus/femoral artery gradient in hydroperoxy fatty acid cis-trans conjugated dienes (from 3.3+1.7 to 0.9_+0.3, n=6, P< 0.01). In this respect, we have in vitro data suggesting that LPO proceeds via the formation of H202/Fe(II) ratios < 0.5, hence, it cannot be promoted by anthracycline semiquinones which usually form H202 in excess of Fe(II). Subsequent studies with NADPH-supplemented drugmetabolizing cytosolic fractions from ex vivo and post mortem myocardial biopsies have shown that DOX is converted to a secondary alcohol. T h i s metabolite does not reduce oxygen, however, it releases Fe(II) from protein(s) that are physicochemically distinct from ferritin. Replacing DOX with less eardiotoxic dannorubicin (DNR), 4'-epi-DOX and 4-demethoxyDNR consistently decreases the yield of secondary alcohols [from 3.9+0.4 to 2.1_+0.1; 1.2!0.2; and 0.6_+0.2 nmol/mg prot./4h, respectively] and the release of Fe(II) [from 6. hk-0.4 to 3.5_+0.1; 1.8 _+0.2; and 0.9-2-0.3 nmol/mg prot./4h, respectively] (n--4, P< 0.01). Thus, secondary alcohol metabolites mediate the eardiotoxieity of anthracyclines, perhaps via free radical- and LPO- independent removal of iron from, and inactivation of, iron-requiring enzymes such as aconitase, ribonucleotide reductase, or others.
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