Cette étude vise à définir l'effet des lipoprotéines de basses densité natives (LDL) et oxydées (ox-LDL) sur les fonctions des cellules endothéliales en relation avec les processus physiopathologiques de l'athérosclérose. Le microscope à force atomique (AFM) fut utilisé en combinaison avec les méthodes biochimiques traditionnelles afin d'acquérir de l'information sur les propriétés biomécaniques des cellules endothéliales. L'AFM est un outil permettant l'acquisition d'images et de mesures de forces quantitatives concernant les propriétés viscoélastiques des cellules vivantes selon leur exposition aux LDL ou ox-LDL. L'AFM rassemble localement des informations sur la membrane cellulaire et le cytosquelette des cellules et ce, de manière non invasive. Il est ensuite possible de corréler les résultats obtenus avec les marquages immunohistochimiques afin d'évaluer la réponse cellulaire suite à une exposition à des LDL ou ox-LDL. Ces données recueillies, les protocoles étant au point, il ne restera plus qu'à effectuer les tests avec les antioxydants afin de déterminer les agents et les dosages appropriés permettant une protection salutaire de l'endothélium. Ce travail amène donc de nouvelles connaissances sur les mécanismes moléculaires fondamentaux de la dysfonction endothéliale en vue éventuellement de développer de nouvelles thérapies cytoprotectrices efficaces. Une méthode d'imagerie des LDL a également été mise au point en utilisant l'AFM. Il est maintenant possible d'obtenir des images de bonne qualité permettant aussi de mesurer les dimensions de LDL individuelles. Cette technique pourrait entre autre servir à évaluer des pathologies touchant les LDL comme le diabète.

Título: Estresse oxidativo e hormônios esteróides na associação entre Distúrbios Respiratórios do Sono e Doença Aterosclerótica Coronariana Introdução: Estudos epidemiológicos mostram a existência de associação entre a Doença Aterosclerótica Coronariana (DAC) e os Distúrbios Respiratórios do Sono (DRS). Evidencias sugerem que o estresse oxidativo gerado pela hipóxia intermitente sofrida pelos pacientes com DRS pode estar relacionado à progressão da DAC. Os hormônios esteróides testosterona, progesterona e estradiol estão relacionados ao estresse oxidativo, e podem ter papel em ambas as doenças. A enzima glutationa S-tranferase utiliza a molécula antioxidante glutationa na detoxificação de compostos que podem ser formados neste processo. A enzima paraoxonase-1 hidrolisa peróxidos lipídicos, atuando sobre as lipoproteínas de baixa densidade oxidadas (ox-LDL). Ox-LDL são marcadores de peroxidação lipídica, e são importantes na formação da placa aterosclerótica. O vaso dilatador óxido nítrico (NO●) é considerado ateroprotetor e pode estar reduzido, agravando a DAC. Objetivos: Estudar o estresse oxidativo e as alterações fisiopatológicas decorrentes da associação entre DRS e DAC, e avaliar a participação dos hormônios esteroides neste processo. Material e Métodos: 56 pacientes com prévio diagnóstico para Doença Aterosclerótica Coronariana (DAC) e avaliação do Índice de Apneias-hipopneias (IAH) para diagnóstico de Distúrbio Respiratório do sono (DRS) foram divididos em dois grupos, 29 pacientes controles e 27 pacientes com DAC, definidos por apresentarem obstrução coronariana >30%. Foram quantificadas as concentrações séricas dos triglicerídeos, HDL, LDL, ferritina, tranferrina e ferro disponível, assim como dos níveis séricos dos hormônios testosterona, estradiol e progesterona, das enzimas paraoxonase-1 e glutationa S-transferase, e das ox-LDL. Foram quantificadas as concentrações de glutationa total, glutationa reduzida, glutationa oxidada e nitritos e nitratos (medida indireta de NO●) em eritrócitos. A concentração do marcador de dano oxidativo em DNA 8-oxo-7,8-dihidro-2’-desoxiguanosina foi obtida em leucócitos. Resultados: Pacientes com DAC possuem reduzida concentração de nitritos e nitratos. A concentração de 8-OHdG, a atividade da GsT, os níveis de glutationa total, glutationa reduzida e glutationa oxidada, assim com o estradiol e a progesterona, não apresentaram relação com DAC ou DRS. Além do IAH, a redução da testosterona e do ferro disponível estão relacionados a DAC. A redução da atividade da paraoxonase-1 e a maior concentração de ox-LDL são preditores de DAC. A testosterona está relacionada à concentração de ferritina, transferrina e ferro disponível nestes pacientes. A ferritina correlacionou-se positivamente ao dano oxidativo em proteínas e com o IAH, negativamente aos níveis de nitritos e nitratos, e é maior nos pacientes com DAC. Conclusão: Baixos níveis de testosterona e ferro disponível, assim com o aumento da ferritina podem estar relacionados à fisiopatologia da associação entre DRS e DAC. Paraoxonase-1 e ox-LDL são importantes preditores de DAC, mas parecem não estar diretamente relacionados ao IAH nestes pacientes. / Title: Oxidative stress and steroid hormones in the association between Sleep Disordered Breathing and Coronary Artery Disease Introduction: Epidemiological studies have shown a possible association between Coronary Artery Disease (CAD) and Sleep Disordered Breathing (SDB). Evidences suggest that oxidative stress generated by the intermittent hypoxia experienced by patients with sleep disorders may be related to progression of CAD. The steroid hormones testosterone, progesterone and estradiol are related to oxidative stress, and may have a role in both diseases. Glutathione S-transferase uses the antioxidant molecule glutathione in the detoxification of compounds that can be formed in this process. The enzyme paraoxonase-1 hydrolyzes lipid peroxides, acting on oxidized low-density lipoproteins (ox-LDL). Ox-LDL are lipid peroxidation markers, being important for the atherosclerotic plaque formation. The vasodilator nitric oxide (NO●) is considered atheroprotective and can be reduced, aggravating DAC. Objective: Evaluate the oxidative stress and the pathophysiological changes arising from the association between SDB and CAD, and the role of steroid hormones in this process. Material and Methods: 56 patients with prior Coronary Artery Disease (CAD) diagnosis and apnea-hypopnea index (AHI) evaluation for diagnosis of sleep-disordered breathing (SDB) were divided into two groups, 29 control patients and 27 patients with CAD, defined by present a coronary obstruction > 30%. The serum concentration of triglycerides, HDL, LDL, ferritin, transferrin and available iron was obtained, as well as the serum levels of the hormones testosterone, estradiol and progesterone, enzymes paraoxonase-1 and glutathione S-transferase, and ox-LDL. Were measured concentrations of total glutathione, reduced glutathione, glutathione disulfide and nitrites and nitrates (NO● indirect measure) in erythrocytes. The concentration of the 8-oxo-7,8-dihydro-2'-deoxyguanosine, oxidative DNA damage marker, was obtained from leukocytes. Results: CAD patients have reduced concentrations of nitrates and nitrites. The concentration of 8-OHdG, GST activity, levels of total glutathione, reduced glutathione and glutathione disulfide, and estradiol and progesterone, showed no relationship with CAD or SDB. In addition to AHI, the reduction of testosterone and iron available are related to CAD. The reduced activity of paraoxonase-1 and the highest concentration of ox-LDL are CAD predictors. Testosterone is related to the concentration of ferritin, transferrin and iron available in these patients. Ferritin was positively correlated to oxidative damage in protein and with the AHI, and negatively to the levels of nitrites and nitrates, and is higher in CAD patients. Conclusion: Low testosterone levels and iron available, as well as the increase ferritin may be related to the pathophysiology of the association between SDB and CAD. Paraoxonase-1 and ox-LDL are important CAD predictors, but do not seem to be directly related to AHI in these patients.

Título: Estresse oxidativo e hormônios esteróides na associação entre Distúrbios Respiratórios do Sono e Doença Aterosclerótica Coronariana Introdução: Estudos epidemiológicos mostram a existência de associação entre a Doença Aterosclerótica Coronariana (DAC) e os Distúrbios Respiratórios do Sono (DRS). Evidencias sugerem que o estresse oxidativo gerado pela hipóxia intermitente sofrida pelos pacientes com DRS pode estar relacionado à progressão da DAC. Os hormônios esteróides testosterona, progesterona e estradiol estão relacionados ao estresse oxidativo, e podem ter papel em ambas as doenças. A enzima glutationa S-tranferase utiliza a molécula antioxidante glutationa na detoxificação de compostos que podem ser formados neste processo. A enzima paraoxonase-1 hidrolisa peróxidos lipídicos, atuando sobre as lipoproteínas de baixa densidade oxidadas (ox-LDL). Ox-LDL são marcadores de peroxidação lipídica, e são importantes na formação da placa aterosclerótica. O vaso dilatador óxido nítrico (NO●) é considerado ateroprotetor e pode estar reduzido, agravando a DAC. Objetivos: Estudar o estresse oxidativo e as alterações fisiopatológicas decorrentes da associação entre DRS e DAC, e avaliar a participação dos hormônios esteroides neste processo. Material e Métodos: 56 pacientes com prévio diagnóstico para Doença Aterosclerótica Coronariana (DAC) e avaliação do Índice de Apneias-hipopneias (IAH) para diagnóstico de Distúrbio Respiratório do sono (DRS) foram divididos em dois grupos, 29 pacientes controles e 27 pacientes com DAC, definidos por apresentarem obstrução coronariana >30%. Foram quantificadas as concentrações séricas dos triglicerídeos, HDL, LDL, ferritina, tranferrina e ferro disponível, assim como dos níveis séricos dos hormônios testosterona, estradiol e progesterona, das enzimas paraoxonase-1 e glutationa S-transferase, e das ox-LDL. Foram quantificadas as concentrações de glutationa total, glutationa reduzida, glutationa oxidada e nitritos e nitratos (medida indireta de NO●) em eritrócitos. A concentração do marcador de dano oxidativo em DNA 8-oxo-7,8-dihidro-2’-desoxiguanosina foi obtida em leucócitos. Resultados: Pacientes com DAC possuem reduzida concentração de nitritos e nitratos. A concentração de 8-OHdG, a atividade da GsT, os níveis de glutationa total, glutationa reduzida e glutationa oxidada, assim com o estradiol e a progesterona, não apresentaram relação com DAC ou DRS. Além do IAH, a redução da testosterona e do ferro disponível estão relacionados a DAC. A redução da atividade da paraoxonase-1 e a maior concentração de ox-LDL são preditores de DAC. A testosterona está relacionada à concentração de ferritina, transferrina e ferro disponível nestes pacientes. A ferritina correlacionou-se positivamente ao dano oxidativo em proteínas e com o IAH, negativamente aos níveis de nitritos e nitratos, e é maior nos pacientes com DAC. Conclusão: Baixos níveis de testosterona e ferro disponível, assim com o aumento da ferritina podem estar relacionados à fisiopatologia da associação entre DRS e DAC. Paraoxonase-1 e ox-LDL são importantes preditores de DAC, mas parecem não estar diretamente relacionados ao IAH nestes pacientes. / Title: Oxidative stress and steroid hormones in the association between Sleep Disordered Breathing and Coronary Artery Disease Introduction: Epidemiological studies have shown a possible association between Coronary Artery Disease (CAD) and Sleep Disordered Breathing (SDB). Evidences suggest that oxidative stress generated by the intermittent hypoxia experienced by patients with sleep disorders may be related to progression of CAD. The steroid hormones testosterone, progesterone and estradiol are related to oxidative stress, and may have a role in both diseases. Glutathione S-transferase uses the antioxidant molecule glutathione in the detoxification of compounds that can be formed in this process. The enzyme paraoxonase-1 hydrolyzes lipid peroxides, acting on oxidized low-density lipoproteins (ox-LDL). Ox-LDL are lipid peroxidation markers, being important for the atherosclerotic plaque formation. The vasodilator nitric oxide (NO●) is considered atheroprotective and can be reduced, aggravating DAC. Objective: Evaluate the oxidative stress and the pathophysiological changes arising from the association between SDB and CAD, and the role of steroid hormones in this process. Material and Methods: 56 patients with prior Coronary Artery Disease (CAD) diagnosis and apnea-hypopnea index (AHI) evaluation for diagnosis of sleep-disordered breathing (SDB) were divided into two groups, 29 control patients and 27 patients with CAD, defined by present a coronary obstruction > 30%. The serum concentration of triglycerides, HDL, LDL, ferritin, transferrin and available iron was obtained, as well as the serum levels of the hormones testosterone, estradiol and progesterone, enzymes paraoxonase-1 and glutathione S-transferase, and ox-LDL. Were measured concentrations of total glutathione, reduced glutathione, glutathione disulfide and nitrites and nitrates (NO● indirect measure) in erythrocytes. The concentration of the 8-oxo-7,8-dihydro-2'-deoxyguanosine, oxidative DNA damage marker, was obtained from leukocytes. Results: CAD patients have reduced concentrations of nitrates and nitrites. The concentration of 8-OHdG, GST activity, levels of total glutathione, reduced glutathione and glutathione disulfide, and estradiol and progesterone, showed no relationship with CAD or SDB. In addition to AHI, the reduction of testosterone and iron available are related to CAD. The reduced activity of paraoxonase-1 and the highest concentration of ox-LDL are CAD predictors. Testosterone is related to the concentration of ferritin, transferrin and iron available in these patients. Ferritin was positively correlated to oxidative damage in protein and with the AHI, and negatively to the levels of nitrites and nitrates, and is higher in CAD patients. Conclusion: Low testosterone levels and iron available, as well as the increase ferritin may be related to the pathophysiology of the association between SDB and CAD. Paraoxonase-1 and ox-LDL are important CAD predictors, but do not seem to be directly related to AHI in these patients.

Título: Estresse oxidativo e hormônios esteróides na associação entre Distúrbios Respiratórios do Sono e Doença Aterosclerótica Coronariana Introdução: Estudos epidemiológicos mostram a existência de associação entre a Doença Aterosclerótica Coronariana (DAC) e os Distúrbios Respiratórios do Sono (DRS). Evidencias sugerem que o estresse oxidativo gerado pela hipóxia intermitente sofrida pelos pacientes com DRS pode estar relacionado à progressão da DAC. Os hormônios esteróides testosterona, progesterona e estradiol estão relacionados ao estresse oxidativo, e podem ter papel em ambas as doenças. A enzima glutationa S-tranferase utiliza a molécula antioxidante glutationa na detoxificação de compostos que podem ser formados neste processo. A enzima paraoxonase-1 hidrolisa peróxidos lipídicos, atuando sobre as lipoproteínas de baixa densidade oxidadas (ox-LDL). Ox-LDL são marcadores de peroxidação lipídica, e são importantes na formação da placa aterosclerótica. O vaso dilatador óxido nítrico (NO●) é considerado ateroprotetor e pode estar reduzido, agravando a DAC. Objetivos: Estudar o estresse oxidativo e as alterações fisiopatológicas decorrentes da associação entre DRS e DAC, e avaliar a participação dos hormônios esteroides neste processo. Material e Métodos: 56 pacientes com prévio diagnóstico para Doença Aterosclerótica Coronariana (DAC) e avaliação do Índice de Apneias-hipopneias (IAH) para diagnóstico de Distúrbio Respiratório do sono (DRS) foram divididos em dois grupos, 29 pacientes controles e 27 pacientes com DAC, definidos por apresentarem obstrução coronariana >30%. Foram quantificadas as concentrações séricas dos triglicerídeos, HDL, LDL, ferritina, tranferrina e ferro disponível, assim como dos níveis séricos dos hormônios testosterona, estradiol e progesterona, das enzimas paraoxonase-1 e glutationa S-transferase, e das ox-LDL. Foram quantificadas as concentrações de glutationa total, glutationa reduzida, glutationa oxidada e nitritos e nitratos (medida indireta de NO●) em eritrócitos. A concentração do marcador de dano oxidativo em DNA 8-oxo-7,8-dihidro-2’-desoxiguanosina foi obtida em leucócitos. Resultados: Pacientes com DAC possuem reduzida concentração de nitritos e nitratos. A concentração de 8-OHdG, a atividade da GsT, os níveis de glutationa total, glutationa reduzida e glutationa oxidada, assim com o estradiol e a progesterona, não apresentaram relação com DAC ou DRS. Além do IAH, a redução da testosterona e do ferro disponível estão relacionados a DAC. A redução da atividade da paraoxonase-1 e a maior concentração de ox-LDL são preditores de DAC. A testosterona está relacionada à concentração de ferritina, transferrina e ferro disponível nestes pacientes. A ferritina correlacionou-se positivamente ao dano oxidativo em proteínas e com o IAH, negativamente aos níveis de nitritos e nitratos, e é maior nos pacientes com DAC. Conclusão: Baixos níveis de testosterona e ferro disponível, assim com o aumento da ferritina podem estar relacionados à fisiopatologia da associação entre DRS e DAC. Paraoxonase-1 e ox-LDL são importantes preditores de DAC, mas parecem não estar diretamente relacionados ao IAH nestes pacientes. / Title: Oxidative stress and steroid hormones in the association between Sleep Disordered Breathing and Coronary Artery Disease Introduction: Epidemiological studies have shown a possible association between Coronary Artery Disease (CAD) and Sleep Disordered Breathing (SDB). Evidences suggest that oxidative stress generated by the intermittent hypoxia experienced by patients with sleep disorders may be related to progression of CAD. The steroid hormones testosterone, progesterone and estradiol are related to oxidative stress, and may have a role in both diseases. Glutathione S-transferase uses the antioxidant molecule glutathione in the detoxification of compounds that can be formed in this process. The enzyme paraoxonase-1 hydrolyzes lipid peroxides, acting on oxidized low-density lipoproteins (ox-LDL). Ox-LDL are lipid peroxidation markers, being important for the atherosclerotic plaque formation. The vasodilator nitric oxide (NO●) is considered atheroprotective and can be reduced, aggravating DAC. Objective: Evaluate the oxidative stress and the pathophysiological changes arising from the association between SDB and CAD, and the role of steroid hormones in this process. Material and Methods: 56 patients with prior Coronary Artery Disease (CAD) diagnosis and apnea-hypopnea index (AHI) evaluation for diagnosis of sleep-disordered breathing (SDB) were divided into two groups, 29 control patients and 27 patients with CAD, defined by present a coronary obstruction > 30%. The serum concentration of triglycerides, HDL, LDL, ferritin, transferrin and available iron was obtained, as well as the serum levels of the hormones testosterone, estradiol and progesterone, enzymes paraoxonase-1 and glutathione S-transferase, and ox-LDL. Were measured concentrations of total glutathione, reduced glutathione, glutathione disulfide and nitrites and nitrates (NO● indirect measure) in erythrocytes. The concentration of the 8-oxo-7,8-dihydro-2'-deoxyguanosine, oxidative DNA damage marker, was obtained from leukocytes. Results: CAD patients have reduced concentrations of nitrates and nitrites. The concentration of 8-OHdG, GST activity, levels of total glutathione, reduced glutathione and glutathione disulfide, and estradiol and progesterone, showed no relationship with CAD or SDB. In addition to AHI, the reduction of testosterone and iron available are related to CAD. The reduced activity of paraoxonase-1 and the highest concentration of ox-LDL are CAD predictors. Testosterone is related to the concentration of ferritin, transferrin and iron available in these patients. Ferritin was positively correlated to oxidative damage in protein and with the AHI, and negatively to the levels of nitrites and nitrates, and is higher in CAD patients. Conclusion: Low testosterone levels and iron available, as well as the increase ferritin may be related to the pathophysiology of the association between SDB and CAD. Paraoxonase-1 and ox-LDL are important CAD predictors, but do not seem to be directly related to AHI in these patients.

No description available.

Cardiovascular disease is the leading cause of mortality in the western world. The pro-inflammatory and pro-proliferative etiology of vascular proliferative diseases is well characterized, while much less is known about the mechanisms of anti-inflammatory and anti-proliferative processes. Interleukin-19 (IL-19) is a newly described member of the IL-10 family of anti-inflammatory interleukins, and our group was the first to discover IL-19 expression in activated, synthetic, but not quiescent, contractile human vascular smooth muscle cells (hVSMC). We also found that IL-19 is anti-inflammatory and anti-proliferative for hVSMC. IL-19 is able to reduce the abundance of COX-2, IL-1β, IL-8, and Cyclin D1 transcripts which contain AU-rich elements (ARE) in their 3'-untranslated regions (3'-UTR). IL-19 is able to reduce the abundance of HuR, a stabilizing RNA-binding protein, which we feel provides a mechanism for these effects. The overall goal of this study is to elucidate IL-19's anti-inflammatory and anti-proliferative mechanism(s) in hVSMC in the context of vascular proliferative diseases. This goal has directed our overall hypothesis: IL-19's anti-proliferative and anti-inflammatory effects in hVSMC are mediated, at least in part, by modulation of HuR abundance and translocation, resulting in decreased stability of mRNA transcripts. HuR functions through a translocation mechanism, and IL-19 is able to reduce HuR cytoplasmic abundance. IL-19 also reduces HuR phosphorylation, which is a pre-requisite for HuR translocation, possibly through a PKCα-dependent mechanism. The stability of ARE-containing transcripts is reduced with IL-19 treatment, and reducing HuR expression by siRNA has the same inhibitory effect. VSMC are important mediators in the initiation of atherosclerosis. Oxidized low-density lipoprotein (ox-LDL) is able to induce IL-19 expression in these cells. VSMC are known to express scavenger receptors that take up ox-LDL. IL-19 is able to reduce the uptake of ox-LDL and the abundance of ox-LDL induced LOX-1 and CX-CL16 scavenger receptors. Interestingly, these scavenger receptors also have ARE in their 3'-UTR. IL-19 is able to reduce ox-LDL induced HuR cytoplasmic abundance. HuR knockdown by siRNA reduces the uptake of ox-LDL by hVSMC. These data suggest that IL-19 reduced scavenger receptor abundance may be due to decreased total and cytoplasmic HuR abundance. IL-19 reduces the abundance of ox-LDL induced COX-2 expression. Taken together, these results demonstrate that IL-19 down-regulates vital steps in vascular proliferative disease processes through an HuR-dependent mechanism. / Molecular and Cellular Physiology

<p>Hypoxia-reoxygenation (H-R) injury is an important clinical phenomenon in patients with coronary artery disease (CAD). Endothelial injury is a critical step in the initiation and progression of atherosclerosis. Therefore, endothelial and cardiomyocyte protection has been considered an effective step in prevention and treatment of CAD.</p><p>To investigate the cardioprotective effect of tocopherols, omega-3 fatty acid [eicosapentaenoic acid (EPA)] and transforming growth factor-β₁ (TGF-β₁) during H-R, calcium tolerant myocytes isolated from adult rats were cultured and subjected to hypoxia for 24 hrs followed by reoxygenation of 3 hrs. All strategies, including tocopherol preparations, EPA and TGF-β₁, showed attenuation of H-R-induced myocyte injury indicated by reduction of lactate dehydrogenase (LDH) release. Both a-tocopherol and a mixed- tocopherols (α-, γ-, and δ-) decreased the effects of H-R on iNOS expression and SOD activity in cultured myocytes. The mixed-tocopherols was more potent than a-tocopherol alone. EPA inhibited H-R-induced lipid peroxidation, MMP-1 expression and p38MAPK phosphorylation. TGF-β₁ blocked the increase in iNOS and PKB phosphorylation as well as the decrease in eNOS expression in cultured myocytes exposed to H-R.</p><p> To further investigate the protective effect of omega-3 fatty acids [docosahexaenoic acid (DHA) and EPA] and TGF-β₁, the cultured endothelial cells were exposed to oxidant injury mediated by oxidized low-density lipoprotein (ox-LDL). Ox-LDL markedly reduced TGF-β₁ release, increased the expression of TGF-β₁ receptors, upregulated the expression of adhesion molecules, P-selectin and ICAM-1, enhanced the adhesion of monocytes to endothelial cells, and decreased protein kinase B (PKB) activation. Both DHA and EPA blocked these effects of ox-LDL on endothelial cells. Exogenous recombinant TGF-β₁ also ameliorated ox-LDL-induced expression of adhesion molecules and monocytes adhesion, which were blocked by antibodies to the TGF-β₁ type 2, but not to the type 3 receptor.</p><p>These observations provide mechanistic insights into H-R and oxidant injury and tissue protection by three different strategies.</p>

Hypoxia-reoxygenation (H-R) injury is an important clinical phenomenon in patients with coronary artery disease (CAD). Endothelial injury is a critical step in the initiation and progression of atherosclerosis. Therefore, endothelial and cardiomyocyte protection has been considered an effective step in prevention and treatment of CAD. To investigate the cardioprotective effect of tocopherols, omega-3 fatty acid [eicosapentaenoic acid (EPA)] and transforming growth factor-β1 (TGF-β1) during H-R, calcium tolerant myocytes isolated from adult rats were cultured and subjected to hypoxia for 24 hrs followed by reoxygenation of 3 hrs. All strategies, including tocopherol preparations, EPA and TGF-β1, showed attenuation of H-R-induced myocyte injury indicated by reduction of lactate dehydrogenase (LDH) release. Both a-tocopherol and a mixed- tocopherols (α-, γ-, and δ-) decreased the effects of H-R on iNOS expression and SOD activity in cultured myocytes. The mixed-tocopherols was more potent than a-tocopherol alone. EPA inhibited H-R-induced lipid peroxidation, MMP-1 expression and p38MAPK phosphorylation. TGF-β1 blocked the increase in iNOS and PKB phosphorylation as well as the decrease in eNOS expression in cultured myocytes exposed to H-R. To further investigate the protective effect of omega-3 fatty acids [docosahexaenoic acid (DHA) and EPA] and TGF-β1, the cultured endothelial cells were exposed to oxidant injury mediated by oxidized low-density lipoprotein (ox-LDL). Ox-LDL markedly reduced TGF-β1 release, increased the expression of TGF-β1 receptors, upregulated the expression of adhesion molecules, P-selectin and ICAM-1, enhanced the adhesion of monocytes to endothelial cells, and decreased protein kinase B (PKB) activation. Both DHA and EPA blocked these effects of ox-LDL on endothelial cells. Exogenous recombinant TGF-β1 also ameliorated ox-LDL-induced expression of adhesion molecules and monocytes adhesion, which were blocked by antibodies to the TGF-β1 type 2, but not to the type 3 receptor. These observations provide mechanistic insights into H-R and oxidant injury and tissue protection by three different strategies.