Deletion of Yin Yang 1 protein in osteosarcoma cells on cell invasion and CXCR4/angiogenesis and metastasis.

We know that the Yin Yang 1 protein (YY1) overexpression is positively and strongly correlated with the degree of malignancy of bone tumors. Therefore, we questioned whether we could influence cell invasiveness by deleting YY1 in human osteosarcoma cells (SaOs-2), as tested in Matrigel-coated filters and metastasis implantation of such osteosarcoma cells in vivo, by serial analysis with nuclear magnetic resonance. Moreover, we focused our work on the chemokine receptor CXCR4 and its inhibition by T22 antibody, as well as on systemic (direct in vivo assay) and computer-assisted imaging of angiogenesis-related metastasis. Results showed that cell invasiveness and metastasis implantation by wild-type SaOs-2 cells, as evaluated by histology and immunohistochemistry, are associated with up-regulation of CXCR4 expression, which in turn was significantly reduced by T22. In addition, deletion of YY1 (siRNAYY1-SaOs-2) induced a significant decrease of cell invasion and metastasis growth. This phenomenon was associated with decreased vascular endothelial growth factor (VEGF)/angiogenesis and a complex rearrangement of the gene expression profile as evaluated by microarray analysis. In conclusion, YY1 and VEGF/CXCR4 seem to intervene in the pathogenesis of the malignant phenotype of osteosarcoma by acting on cell invasiveness and metastasis growth.

The influence of pomegranate fruit extract in comparison to regular pomegranate juice and seed oil on nitric oxide and arterial function in obese Zucker rats.

Metabolic syndrome includes most widely distributed clinical conditions such as obesity, hypertension, dislipidemia, and diabetes. Pomegranate fruit extract (PFE), rich in polyphenolic antioxidants, reduces the expression of oxidation-sensitive genes at the sites of perturbed shear-stress. The aim of this study was to evaluate the effect of PFE in comparison to regular pomegranate juice (PJ) and seed oil on the biological actions of nitric oxide (NO) and the arterial function in obese Zucker rats, a model of metabolic syndrome. Our results indicated that supplementation with PFE or PJ significantly decreased the expression of vascular inflammation markers, thrombospondin (TSP), and cytokine TGFbeta1 (P<0.05), whereas seed oil supplementation had a significant effect only on TSP-1 expression (P <0.05). Plasma nitrate and nitrite (NO(x)) levels were significantly increased by PFE and PJ (P<0.05). Furthermore, the effect of PFE in increasing endothelial NO synthase (eNOS) expression was comparable to that of PJ. These data highlight possible clinical applications of PFE in metabolic syndrome.

Effects of a pomegranate fruit extract rich in punicalagin on oxidation-sensitive genes and eNOS activity at sites of perturbed shear stress and atherogenesis.

BACKGROUND: Atherosclerosis is enhanced in arterial segments exposed to disturbed flow. Perturbed shear stress increases the expression of oxidation-sensitive responsive genes (such as ELK-1 and p-CREB). Polyphenolic antioxidants contained in the juice derived from the pomegranate contribute to the reduction of oxidative stress and atherogenesis during disturbed shear stress. AIM OF THE STUDY: To evaluate the effects of intervention with the Pomegranate Fruit Extract (PFE) rich in polyphones (punicalagin, which is a potent antioxidant) on ELK-1, p-CREB, and endothelial nitric oxide synthase (eNOS) expression induced by high shear stress in vitro and in vivo. RESULTS: At the doses used in the study, both the PFE and the regular pomegranate juice concentrate reduced the activation of ELK-1 and p-CREB and increased eNOS expression (which was decreased by perturbed shear stress) in cultured human endothelial cells and in atherosclerosis-prone areas of hypercholesterolemic mice. PFE and pomegranate juice increased cyclic GMP levels while there was no significant effect of both compounds on the conversion of L-arginine to L-citrulline. Administration of these compounds to hypercholesterolemic mice significantly reduced the progression of atherosclerosis and isoprostane levels and increased nitrates. This protective effect was relevant with PFE. Vasomotor reactivity was improved and EC(25) values in response to Ach and NONOate were significantly increased in treated mice in comparison to controls. CONCLUSION: This study indicates that the proatherogenic effects induced by perturbed shear stress can be also reversed by chronic administration of PFE.

Physical training and metabolic supplementation reduce spontaneous atherosclerotic plaque rupture and prolong survival in hypercholesterolemic mice.

Moderate physical exercise (PE) combined with metabolic treatment (MT) (antioxidants and l-arginine) are well known to reduce atherosclerotic lesion formation in hypercholesterolemic mice. However, the long-term beneficial effects on unstable atheroma remain poorly understood. We started early PE training in large groups of 6-week-old hypercholesterolemic mice (by graduated swimming) alone or in combination with nutritional supplementation (1.0% vitamin E added to the chow and 0.05% vitamin C and 6% l-arginine added to the drinking water). Inactive controls did not receive PE. The spontaneous development of atherosclerotic plaque rupture (associated with advanced atherosclerosis) and survival rates were evaluated. Moderate PE elicited an increase in plasma levels of nitric oxide. Early combined treatment with PE and MT in the hypercholesterolemic mice significantly reduced lesions (also detected noninvasively at 10 months) and spontaneous atherosclerotic plaque rupture and prolonged survival more effectively than each intervention alone. Thus, early concerted actions of MT and PE improve the natural history of atherosclerotic lesions and reduce the plaque instability in hypercholesterolemic mice.

The role of oxidative stress in adult critical care.

Oxidative stress defines an imbalance in production of oxidizing chemical species and their effective removal by protective antioxidants and scavenger enzymes. Evidence of massive oxidative stress is well established in adult critical illnesses characterized by tissue ischemia-reperfusion injury and by an intense systemic inflammatory response such as during sepsis and acute respiratory distress syndrome. Oxidative stress could exacerbate organ injury and thus overall clinical outcome. We searched MEDLINE databases (January 1966 to June 2005). For interventional studies, we accepted only randomized trials. Several small clinical trials have been performed in order to reduce oxidative stress by supplementation of antioxidants alone or in combination with standard therapies. These studies have reported controversial results. Newer large multicenter trials with antioxidant supplementation should be performed, considering administration at an early stage of illness and a wider population of critically ill patients.

Beneficial effects of pomegranate juice on oxidation-sensitive genes and endothelial nitric oxide synthase activity at sites of perturbed shear stress.

Atherosclerosis is enhanced in arterial segments exposed to disturbed flow. Perturbed shear stress increases the expression of oxidation-sensitive responsive genes (such as ELK-1 and p-JUN) in the endothelium. Evidence suggests that polyphenolic antioxidants contained in the juice derived from the pomegranate can contribute to the reduction of oxidative stress and atherogenesis. The aim of the present study was to evaluate the effects of intervention with pomegranate juice (PJ) on oxidation-sensitive genes and endothelial NO synthase (eNOS) expression induced by high shear stress in vitro and in vivo. Cultured human coronary artery endothelial cells (EC) exposed to high shear stress in vitro and hypercholesterolemic mice were used in this study. PJ concentrate reduced the activation of redox-sensitive genes (ELK-1 and p-JUN) and increased eNOS expression (which was decreased by perturbed shear stress) in cultured EC and in atherosclerosis-prone areas of hypercholesterolemic mice. Moreover, oral administration of PJ to hypercholesterolemic mice at various stages of disease reduced significantly the progression of atherosclerosis. This experimental study indicates that the proatherogenic effects induced by perturbed shear stress can be reversed by chronic administration of PJ. This approach may have implications for the prevention or treatment of atherosclerosis and its clinical manifestations.

Long-term combined beneficial effects of physical training and metabolic treatment on atherosclerosis in hypercholesterolemic mice.

The pathogenic mechanisms by which physical exercise influences atherosclerotic lesion formation remain poorly understood. Because vigorous physical training increases oxidative stress, this study tested the hypothesis that graduated and moderate physical exercise together with metabolic intervention (l-arginine and antioxidants) may contribute to increased vascular protection. Exercise training in mice was induced by graduated swimming. In hypercholesterolemic male mice on an atherogenic high-cholesterol diet, graduated and moderate exercise lowered plasma cholesterol and decreased atherosclerotic lesions compared with sedentary control mice. Antioxidants (1.0% vitamin E added to the chow and 0.05% vitamin C added to the drinking water) and l-arginine (6% in drinking water) supplementation to exercising hypercholesterolemic mice further and synergistically reduced atherosclerosis compared with untreated exercised mice. Arterial oxidation-specific epitopes and systemic oxidative stress were reduced by metabolic intervention. Graduated chronic exercise elicited an increase in production of nitric oxide through increased endothelial nitric oxide synthase expression and ameliorated scavenger activities. Thus, metabolic intervention with l-arginine and antioxidants together with graduated and moderate exercise training reduce atherosclerotic lesion formation.