Detrimental effects of Bartonella henselae are counteracted by L-arginine and nitric oxide in human endothelial progenitor cells.

The recruitment of circulating endothelial progenitor cells (EPCs) might have a beneficial effect on the clinical course of several diseases. Endothelial damage and detachment of endothelial cells are known to occur in infection, tissue ischemia, and sepsis. These detrimental effects in EPCs are unknown. Here we elucidated whether human EPCs internalize Bartonella henselae constituting a circulating niche of the pathogen. B. henselae invades EPCs as shown by gentamicin protection assays and transmission electron microscopy (TEM). Dil-Ac-LDL/lectin double immunostaining and fluorescence-activated cell sorting (FACS) analysis of EPCs revealed EPC bioactivity after infection with B. henselae. Nitric oxide (NO) and its precursor l-arginine (l-arg) exert a plethora of beneficial effects on vascular function and modulation of immune response. Therefore, we tested also the hypothesis that l-arg (1-30 mM) would affect the infection of B. henselae or tumor necrosis factor (TNF) in EPCs. Our data provide evidence that l-arg counteracts detrimental effects induced by TNF or Bartonella infections via NO (confirmed by DETA-NO and L-NMMA experiments) and by modulation of p38 kinase phosphorylation. Microarray analysis indicated several genes involved in immune response were differentially expressed in Bartonella-infected EPCs, whereas these genes returned in steady state when cells were exposed to sustained doses of l-arg. This mechanism may have broad therapeutic applications in tissue ischemia, angiogenesis, immune response, and sepsis.

Long-term treatment with sulfhydryl angiotensin-converting enzyme inhibition reduces carotid intima-media thickening and improves the nitric oxide/oxidative stress pathways in newly diagnosed patients with mild to moderate primary hypertension.

BACKGROUND: Sulfhydryl angiotensin-converting enzyme (ACE) inhibitors exert antiatherosclerotic effects in preclinical models and antioxidant effects in patients. However, whether ACE inhibitors have any clinically significant antiatherogenic effects remains still debated. OBJECTIVES: In mildly hypertensive patients, we evaluated the effect of the sulfhydryl ACE inhibitor zofenopril in comparison with the carboxylic ACE inhibitor enalapril on carotid atherosclerosis (intima-media thickness [IMT] and vascular lumen diameter) and systemic oxidative stress (nitrite/nitrate, asymmetrical dimethyl-l-arginine, and isoprostanes). METHODS: In 2001, we started a small prospective randomized clinical trial on 48 newly diagnosed mildly hypertensive patients with no additional risk factors for atherosclerosis (eg, hyperlipidemia, smoke habit, familiar history of atherosclerosis-related diseases or diabetes). Patients were randomly assigned either to the enalapril (20 mg/d, n = 24) or the zofenopril group (30 mg/d, n = 24); the planned duration of the trial was 5 years. Carotid IMT and vascular lumen diameter were determined by ultrasonography for all patients at baseline and at 1, 3, and 5 years. Furthermore, nitrite/nitrate, asymmetrical dimethyl-l-arginine, and isoprostane levels were measured. RESULTS: In our conditions, IMT of the right and left common carotid arteries was similar at baseline in both groups (P = NS). Intima-media thickness measurements until 5 years revealed a significant reduction in the zofenopril group but not in the enalapril group (P < .05 vs enalapril-treated group). This effect was coupled with a favorable nitric oxide/oxidative stress profile in the zofenopril group. CONCLUSIONS: Long-term treatment with the sulfhydryl ACE inhibitor zofenopril besides its blood pressure-lowering effects may slow the progression of IMT of the carotid artery in newly diagnosed mildly hypertensive patients.

Therapeutic dose of nebivolol, a nitric oxide-releasing beta-blocker, reduces atherosclerosis in cholesterol-fed rabbits.

Nitric oxide (NO) exerts a plethora of vascular beneficial effects. The NO-releasing beta-blocker nebivolol is a racemic mixture of D/L-enantiomers that displays negative inotropic as well as direct vasodilating activity. The in vivo antiatherogenic activity of therapeutic doses of the beta-blocker with antioxidant properties carvedilol (12.5mg/day) or nebivolol (5mg/day) was tested in cholesterol-fed rabbits. Animals received a 1% cholesterol-rich diet alone (controls) or mixed with drugs (treated animals) for 8 weeks. While it did not affect hyperlipidemia, nebivolol inhibited the development of atherosclerosis, expressed as computer-assisted imaging analysis of aortic area covered by lesions (23.3+/-4.1% in treated vs 38.2+/-6.4% in control animals, p<0.01). Differently, in our experimental condition of therapeutic drug doses, this antiatherogenic effect did not reach statistical significance in rabbits treated with carvedilol (32.5+/-5.1% aortic area covered by lesions, p=NS vs controls). Plasma nitrates increased in rabbits treated with nebivolol while both beta-blockers reduced LDL oxidation. Moreover, nebivolol induced a consistent increase of endothelial reactivity and aortic eNOS expression compared with control animals (p<0.05) and those receiving carvedilol (p<0.05). Since NO may exert beneficial effects in atherosclerosis, a NO-dependent mechanism could explain this data. These observations suggest that the NO-releasing beta-blocker, nebivolol, might represent an effective pharmacological approach for preventing atherosclerotic lesion progression.

Functional impairment of hematopoietic progenitor cells in patients with coronary heart disease.

The circulating form of endothelial progenitors cells (EPCs) are derived from bone marrow (BM)-derived hematopoietic stem cells (HSCs). Enhanced mobilization of EPCs was shown to be linked to cardiac diseases. This study investigated whether reduced EPC levels in advanced coronary heart disease (CHD) are secondary to a functional exhaustion of HSCs in the BM or to reduced mobilization. Number and functional properties of EPCs were assessed in 15 healthy controls, and 40 patients with CHD. The colony-forming unit (CFU) capacity of BM-derived mononuclear cells and the CD34+ HSC number were examined in four healthy volunteers, and 15 CHD patients. EPC number was reduced in CHD patients (P < 0.01 vs. controls). Moreover, the migratory capacity was significantly impaired in EPCs of CHD patients (P < 0.05 vs. controls). On multivariate analysis, CHD was an independent predictor of functional EPC impairment. CFUs were reduced in CHD patients (59.6 +/- 21.2 vs. 75.4 +/- 25.8 in controls, P < 0.05). CHD was also predictor of impaired CFU capacity. In this small clinical study, CHD is associated with selective impairment of HSC function in the BM and in the peripheral blood, which may contribute to impairment of cardiac function.

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.

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.

Role of oxidative stress in experimental sepsis and multisystem organ dysfunction.

Massive increase in radical species can lead to oxidative stress, promoting cell injury and death. This review focuses on experimental evidence of oxidative stress in critical illnesses, sepsis and multisystem organ dysfunction. Oxidative stress could negatively affect organ injury and thus overall survival of experimental models. Based on this experimental evidence, we could improve the rationale of supplementation of antioxidants alone or in combination with standard therapies aimed to reduce oxidative stress as novel adjunct treatment in critical care.

Oxidation-sensitive mechanisms, vascular apoptosis and atherosclerosis.

Increased generation of oxidants, resulting from disruption of aerobic metabolism and from respiratory burst, is an essential defense mechanism against pathogens and aberrant cells. However, oxidative stress can also trigger and enhance deregulated apoptosis or programmed cell death, characteristic of atherosclerotic lesions. Oxidation-sensitive mechanisms also modulate cellular signaling pathways that regulate vascular expression of cytokines and growth factors, and influence atherogenesis, in particular when increased levels of plasma lipoproteins provide ample substrate for lipid peroxidation and lead to increased formation of adducts with lipoprotein amino acids. In some cases, increased oxidation and apoptosis in a group of cells might be beneficial for survival and function of other groups of arterial cells. However, overall, oxidation and apoptosis appear to promote the progression of diseased arteries towards a lesion that is vulnerable to rupture, and to give rise to myocardial infarction and ischemic stroke. Recent rapid advances in our understanding of the interactions between oxidative stress, apoptosis and arterial gene regulation suggest that selective interventions targeting these biological functions have great therapeutic potential.

Therapeutic angiogenesis in diabetic apolipoprotein E-deficient mice using bone marrow cells, functional hemangioblasts and metabolic intervention.

OBJECTIVE: Peripheral arterial disease (PAD) is a major health problem especially when associated to concomitant diabetes and hypercholesterolemia. Hyperglycemia with an overwhelming generation of oxygen radicals and formation of glycation end-products exacerbates oxidation-sensitive mechanisms activated by tissue ischemia. Administration of autologous bone marrow cells (BMC) is an increasing notable intervention to induce therapeutic angiogenesis, ameliorated by metabolic intervention (MT). Recently, hemangioblasts (HS) with functional properties were isolated. METHODS: The effects of integrate regimen with intravenous BMC, HS, and MT (1.0% vitamin E, 0.05% vitamin C, and 6% l-arginine) were examined in the ischemic hindlimb of ApoE(-/-) diabetic and non-diabetic. Blood flow ratio was monitored by use of a laser Doppler blood flowmeter. Capillary density was determined in sections of the adductor and semimembranous muscles with antibody against CD31. RESULTS: BMC or HS alone, and BMC plus HS increased blood flow and capillary densities and decreased interstitial fibrosis. These effects were amplified by additional MT, at least in part, through the nitric oxide pathway, reduction of systemic oxidative stress and macrophage infiltration. Investigation of molecular mechanisms in bone marrow (BM)-derived progenitor cells from mice revealed that BMC therapy and, more consistently, in combination with MT ameliorated functional activity via decreased cellular senescence and increased telomerase and chemokine CXCR4 activities. Telomerase activity was also increased by HS alone or HS+MT and, more consistently, by BMC+HS alone or in combination with MT. CONCLUSIONS/INTERPRETATION: Intravenous autologous BMC and HS intervention together with MT increased therapeutic angiogenesis in the ApoE(-/-) diabetic mouse hindlimb.

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.

Therapeutic effects of autologous bone marrow cells and metabolic intervention in the ischemic hindlimb of spontaneously hypertensive rats involve reduced cell senescence and CXCR4/Akt/eNOS pathways.

Peripheral arterial disease (PAD) is a major health problem, especially when associated with severe hypertension. Administration of autologous bone marrow cells (BMCs) is emerging as a novel intervention to induce neoangiogenesis in ischemic limb models and in patients with PAD. This study evaluates the neovascularization capacity of BMCs alone or in combination with metabolic cotreatment (0.8% vitamin E, 0.05% vitamin C, and 5% of L-arginine) in a rat model of ischemic hindlimbs of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Molecular mechanisms were investigated in bone marrow-derived endothelial progenitor cells (BM-EPC) derived from rats. BMC therapy increased blood flow and capillary densities and Ki67 proliferative marker, and it decreased interstitial fibrosis. These effects were amplified by metabolic cotreatment, an intervention that induces vascular protection at least partly through the nitric oxide (NO)/endothelial nitric oxide synthase (eNOS) pathway, reduction of systemic oxidative stress, and macrophage activation. In addition, BMC therapy alone and, more consistently, in combination with metabolic treatment, ameliorated BM-EPC functional activity via decreased cellular senescence and improved homing capacity by increasing CXCR4-expression levels. These data suggest potential therapeutic effects of autologous BMCs and metabolic treatment in hypertensive PAD patients.

Brain protection using autologous bone marrow cell, metalloproteinase inhibitors, and metabolic treatment in cerebral ischemia.

Despite advances in imaging, understanding the underlying pathways, and clinical translation of animal models of disease there remains an urgent need for therapies that reduce brain damage after stroke and promote functional recovery in patients. Blocking oxidant radicals, reducing matrix metalloproteinase-induced neuronal damage, and use of stem cell therapy have been proposed and tested individually in prior studies. Here we provide a comprehensive integrative management approach to reducing damage and promoting recovery by combining biological therapies targeting these areas. In a rat model of transient cerebral ischemia (middle cerebral artery occlusion) gene delivery vectors were used to overexpress tissue inhibitor of matrix metalloproteinase 1 and 2 (TIMP1 and TIMP2) 3 days before ischemia. After occlusion, autologous bone marrow cells alone or in combination with agents to improve NO bioavailability were administered intraarterially. When infarct size, BrdU incorporation, and motor function recovery were determined in the treatment groups the largest beneficial effect was seen in rats receiving the triple combined therapy, surpassing effects of single or double therapies. Our study highlights the utility of combined drug, gene, and cell therapy in the treatment of stroke.

Therapeutic effects of concurrent autologous bone marrow cell infusion and metabolic intervention in ischemia-induced angiogenesis in the hypercholesterolemic mouse hindlimb.

Lower-limb ischemia is a major health problem especially when associated to hypercholesterolemia. Because of the absence of effective treatment in the advanced stages of the disease, amputation is undertaken to alleviate unbearable symptoms. Since tissue ischemia and hypercholesterolemia are associated with an overwhelming generation of oxygen radicals, metabolic intervention with antioxidants and l-arginine can induce beneficial effects beyond those achieved by a novel therapeutic approach represented by the use of autologous bone marrow cells (BMCs). The protective effect of BMCs and vascular protection by metabolic cotreatment (1.0% vitamin E added to the chow, 0.05% vitamin C and 6% l-arginine added to the drinking water) were examined in ischemia-induced angiogenesis in the hypercholesterolemic mouse hindlimb. Intravenous BMC therapy improved blood flow and increased capillary densities. This beneficial effect was amplified by metabolic cotreatment, an intervention inducing vascular protection, at least in part, through the nitric oxide pathway, reduction of systemic oxidative stress and macrophage activation.

Nitric oxide and atherosclerosis: an update.

Nitric oxide (NO) is a molecule that has gained recognition as a crucial modulator of vascular disease. NO has a number of intracellular effects that lead to vasorelaxation, endothelial regeneration, inhibition of leukocyte chemotaxis, and platelet adhesion. Endothelium damage induced by atherosclerosis leads to the reduction in bioactivity of endothelial NO synthase (eNOS) with subsequent impaired release of NO together with a local enhanced degradation of NO by increased generation of reactive oxygen species with subsequent cascade of oxidation-sensitive mechanisms in the arterial wall. Many commonly used vasculoprotective agents have their therapeutic actions through the production of NO. L-Arginine, the precursor of NO, has demonstrated beneficial effects in atherosclerosis and disturbed shear stress. Finally, eNOS gene polymorphism might be an additional risk factor that may contribute to predict cardiovascular events. However, further studies are needed to understand the possible clinical implications of these correlations.

Pomegranate juice reduces oxidized low-density lipoprotein downregulation of endothelial nitric oxide synthase in human coronary endothelial cells.

We examined the hypothesis that pomegranate juice (PJ) can revert the potent downregulation of the expression of endothelial nitric-oxide synthase (NOSIII) induced by oxidized low-density liporotein (oxLDL) in human coronary endothelial cells. Western blot and Northern blot analyses showed a significant decrease of NOSIII expression after a 24-h treatment with oxLDL. Accordingly, we observed a significant dose-dependent reduction in nitric oxide bioactivity represented by both basal and bradykinin-stimulated cellular cGMP accumulation. These phenomena were corrected significantly by the concomitant treatment with PJ. Our data suggest that PJ can exert beneficial effects on the evolution of clinical vascular complications, coronary heart disease, and atherogenesis in humans by enhancing the NOSIII bioactivity.

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.

Autologous bone marrow cell therapy and metabolic intervention in ischemia-induced angiogenesis in the diabetic mouse hindlimb.

Peripheral arterial disease (PAD) is a major health problem especially when associated to diabetes. Administration of autologous bone marrow cells (BMC) is emerging as a novel intervention to induce therapeutic angiogenesis in experimental ischemic limb models and in patients with PAD. Since tissue ischemia and diabetes are associated with an overwhelming generation of oxygen radicals and detrimental effects due to formation of glycosylation end-products, metabolic intervention with antioxidants and L-arginine can confer beneficial effects beyond those achieved by BMC alone. The effects of cotreatment with intravenous BMCs and metabolic vascular protection (1.0% vitamin E, 0.05% vitamin C, and 6% L-arginine) were examined in the ischemic hindlimb of diabetic and non diabetic mice. BMC therapy increased blood flow and capillary densities and Ki67 proliferative marker, and decreased interstitial fibrosis. This effect was amplified by metabolic cotreatment, an intervention inducing vascular protection, at least in part, through the nitric oxide pathway, reduction of systemic oxidative stress, and macrophage activation.

Beneficial effects of concurrent autologous bone marrow cell therapy and metabolic intervention in ischemia-induced angiogenesis in the mouse hindlimb.

Lower-limb ischemia is a major health problem. Because of the absence of effective treatment in the advanced stages of the disease, amputation is undertaken to alleviate unbearable symptoms. Novel therapeutic approaches include the intramuscular use of autologous bone marrow cells (BMCs). Because tissue ischemia is associated with an overwhelming generation of oxygen radicals and negative effects due to perturbed shear-stress, metabolic intervention with antioxidants and l-arginine could potentially induce beneficial effects beyond those achieved by BMCs. The protective effect of autologous BMCs and vascular protection by metabolic cotreatment (1.0% vitamin E added to the chow and 0.05% vitamin C and 6% l-arginine added to the drinking water) were examined in ischemia-induced angiogenesis in the mouse hindlimb, a model of extensive acute peripheral arterial occlusion. i.v. BMC therapy improved blood flow and increased capillary densities and expression of Ki-67, a proliferation-associated protein. This beneficial effect was amplified by metabolic cotreatment, an intervention inducing vascular protection, at least in part, through the nitric oxide pathway, reduction of systemic oxidative stress, and macrophage activation. Therefore, although a cautious approach is mandatory when experimental findings are extended to human diseases, autologous BMCs together with metabolic intervention could be an effective clinical treatment for peripheral arterial disease.

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.