Moderate consumption of red wine (cabernet sauvignon) improves ischemia-induced neovascularization in ApoE-deficient mice: effect on endothelial progenitor cells and nitric oxide

Endothelial progenitor cells as an emerging cardiovascular risk factor in the field of food and nutrition research: advances and challenges

Dietary modifications can help prevent many cardiovascular disease (CVD) events. Endothelial progenitor cells (EPCs) actively contribute to cardiovascular system maintenance and could function as surrogate markers for evaluating improvement in cardiovascular health resulting from nutritional interventions. This review summarizes the latest research progress on the impact of food and nutrients on EPCs, drawing on evidence from human, animal, and in vitro studies. Additionally, current trends and challenges faced in the field are highlighted. Findings from studies examining cells as EPCs are generally consistent, demonstrating that a healthy diet, such as the Mediterranean diet or a supervised diet for overweight people, specific foods like olive oil, fruit, vegetables, red wine, tea, chia, and nutraceuticals, and certain nutrients such as polyphenols, unsaturated fats, inorganic nitrate, and vitamins, generally promote higher EPC numbers and enhanced EPC function. Conversely, an unhealthy diet, such as one high in sugar substitutes, salt, or fructose, impairs EPC function. Research on outgrowth EPCs has revealed that various pathways are involved in the modulation effects of food and nutrients. The potential of EPCs as a biomarker for assessing the effectiveness of nutritional interventions in preventing CVDs is immense, while further clarification on definition and characterization of EPCs is required.

Bach1 plays an important role in angiogenesis through regulation of oxidative stress

Bach1 is a known transcriptional repressor of the heme oxygenase-1 (HO-1) gene. The purpose of this study was to determine whether angiogenesis is accelerated by genetic ablation of Bach1 in a mouse ischemic hindlimb model. Hindlimb ischemia was surgically induced in wild-type (WT) mice, Bach1-deficient (Bach1-/-) mice, apolipoprotein E-deficient (ApoE-/-) mice, and Bach1/ApoE double-knockout (Bach1-/-/ApoE-/-) mice. Blood flow recovery after hindlimb ischemia showed significant improvement in Bach1-/- mice compared with that in WT mice. Bach1-/-/ApoE-/- mice showed significantly improved blood flow recovery compared with that in ApoE-/- mice to the level of that in WT mice. Migration of endothelial cells in ApoE-/- mice was significantly decreased compared with that in WT mice. Migration of endothelial cells significantly increased in Bach1-/-/ApoE-/- mice compared with that in ApoE-/- mice to the level of that in WT mice. The expression levels of HO-1, peroxisome proliferator-activated receptor γ co-activator-1α, angiopoietin 1, and fibroblast growth factor 2 in endothelial cells isolated from Bach1-/-/ApoE-/- mice were significantly higher than those in ApoE-/- mice. Oxidative stress assessed by anti-acrolein antibody staining in ischemic tissues and urinary 8-isoPGF2α excretion were significantly increased in ApoE-/- mice compared with those in WT and Bach1-/- mice. Oxidative stress was reduced in Bach1-/-/ApoE-/- mice compared with that in ApoE-/- mice. These findings suggest that genetic ablation of Bach1 plays an important role in ischemia-induced angiogenesis under the condition of increased oxidative stress. Bach1 could be a potential therapeutic target to reduce oxidative stress and potentially improve angiogenesis for patients with peripheral arterial disease.

Silencing MicroRNA-137-3p, which Targets RUNX2 and CXCL12 Prevents Steroid-induced Osteonecrosis of the Femoral Head by Facilitating Osteogenesis and Angiogenesis

The main pathogenesis of steroid-induced osteonecrosis of the femoral head (SONFH) includes decreased osteogenic capacity of bone marrow-derived mesenchymal stem cells (BMSCs) and damaged blood supply to the femoral head. MicroRNAs (miRNAs) have been shown to play prominent roles in SONFH development. However, there is no report that a specific miRNA targeting two genes in two different pathogenic pathways has been applied to this disease. The present study investigated the effects of transplantation of miR-137-3p-silenced BMSCs on the prevention and early treatment of SONFH. First, western blotting and dual luciferase assays were employed to verify that miR-137-3p directly targets Runx2 and CXCL12. Then, silencing of miR-137-3p was found to facilitate osteogenic differentiation of BMSCs, which was confirmed by alkaline phosphatase (ALP) staining, alizarin red staining and qRT-PCR. Silencing of miR-137-3p also promoted angiogenesis by human umbilical vein endothelial cells (HUVECs) in the presence or absence of glucocorticoids. Thereafter, overexpression of Runx2 and CXCL12 without the 3′ untranslated region (3′UTR) partially rescued the effects of miR-137-3p on osteogenesis and angiogenesis, respectively. This finding further supported the hypothesis that miR-137-3p exerts its functions partly by regulating the genes, Runx2 and CXCL12. We also demonstrated that SONFH was partially prevented by transplantation of miR-137-3p-silenced BMSCs into a rat model. Micro-CT and histology showed that the transplantation of miR-137-3p-silenced BMSCs significantly improved bone regeneration. Additionally, the results of enzyme-linked immunosorbent assays (ELISA) and flow cytometry suggested that stromal cell-derived factor-1α (SDF-1α) and endothelial progenitor cells (EPCs) participated in the process of vascular repair. Taken together, these findings show that silencing of miR-137-3p directly targets the genes, Runx2 and CXCL12, which can play critical roles in SONFH repair by facilitating osteogenic differentiation and mobilizing EPCs.

Flavin Oxidase-Induced ROS Generation Modulates PKC Biphasic Effect of Resveratrol on Endothelial Cell Survival

Background: Dietary intake of natural antioxidants is thought to impart protection against oxidative-associated cardiovascular diseases. Despite many in vivo studies and clinical trials, this issue has not been conclusively resolved. Resveratrol (RES) is one of the most extensively studied dietary polyphenolic antioxidants. Paradoxically, we have previously demonstrated that high RES concentrations exert a pro-oxidant effect eventually elevating ROS levels leading to cell death. Here, we further elucidate the molecular determinants underpinning RES-induced oxidative cell death. Methods: Using human umbilical vein endothelial cells (HUVECs), the effect of increasing concentrations of RES on DNA synthesis and apoptosis was studied. In addition, mRNA and protein levels of cell survival or apoptosis genes, as well as protein kinase C (PKC) activity were determined. Results: While high concentrations of RES reduce PKC activity, inhibit DNA synthesis and induce apoptosis, low RES concentrations elicit an opposite effect. This biphasic concentration-dependent effect (BCDE) of RES on PKC activity is mirrored at the molecular level. Indeed, high RES concentrations upregulate the proapoptotic Bax, while downregulating the antiapoptotic Bcl-2, at both mRNA and protein levels. Similarly, high RES concentrations downregulate the cell cycle progression genes, c-myc, ornithine decarboxylase (ODC) and cyclin D1 protein levels, while low RES concentrations display an increasing trend. The BCDE of RES on PKC activity is abrogated by the ROS scavenger Tempol, indicating that this enzyme acts downstream of the RES-elicited ROS signaling. The RES-induced BCDE on HUVEC cell cycle machinery was also blunted by the flavin inhibitor diphenyleneiodonium (DPI), implicating flavin oxidase-generated ROS as the mechanistic link in the cellular response to different RES concentrations. Finally, PKC inhibition abrogates the BCDE elicited by RES on both cell cycle progression and pro-apoptotic gene expression in HUVECs, mechanistically implicating PKC in the cellular response to different RES concentrations. Conclusions: Our results provide new molecular insight into the impact of RES on endothelial function/dysfunction, further confirming that obtaining an optimal benefit of RES is concentration-dependent. Importantly, the BCDE of RES could explain why other studies failed to establish the cardio-protective effects mediated by natural antioxidants, thus providing a guide for future investigation looking at cardio-protection by natural antioxidants.

Neonatal exposure to high oxygen levels leads to impaired ischemia-induced neovascularization in adulthood

Adverse perinatal conditions can lead to developmental programming of cardiovascular diseases. Prematurely born infants are often exposed to high oxygen levels, which in animal models has been associated with endothelial dysfunction, hypertension, and cardiac remodeling during adulthood. Here we found that adult mice that have been transiently exposed to O₂ after birth show defective neovasculariation after hindlimb ischemia, as demonstrated by impaired blood flow recovery, reduced vascular density in ischemic muscles and increased tissue damages. Ischemic muscles isolated from mice exposed to O₂ after birth exhibit increased oxidative stress levels and reduced expression of superoxide dismutase 1 (SOD1) and vascular endothelial growth factor (VEGF). Pro-angiogenic cells (PACs) have been shown to have an important role for postnatal neovascularisation. We found that neonatal exposure to O₂ is associated with reduced number of PACs in adults. Moreover, the angiogenic activities of both PACs and mature mouse aortic endothelial cells (MAECs) are significantly impaired in mice exposed to hyperoxia after birth. Our results indicate that neonatal exposure to high oxygen levels leads to impaired ischemia-induced neovascularization during adulthood. The mechanism involves deleterious effects on oxidative stress levels and angiogenic signals in ischemic muscles, together with dysfunctional activities of PACs and mature endothelial cells.

Natural compound bavachalcone promotes the differentiation of endothelial progenitor cells and neovascularization through the RORα-erythropoietin-AMPK axis

In cardiovascular diseases, endothelial function is impaired and the level of circulating endothelial progenitor cells (EPCs) is low. This study investigated whether the natural bioactive component bavachalcone (BavaC) induces the differentiation of EPCs and neovascularization in vivo; the underlying mechanisms were also examined. We observed that the treatment of rat bone marrow–derived cells with a very low dose of BavaC significantly promoted EPC differentiation. In our hindlimb ischemia models, low–dose BavaC administered orally for 14 days stimulated the recovery of ischemic hindlimb blood flow, increased circulating EPCs, and promoted capillary angiogenesis. The BavaC treatment of rat bone marrow cells for 24 h initiated the AMP–activated protein kinase (AMPK) activity required for the differentiation of EPCs. Further testing revealed that BavaC and CGP52608, a retinoic acid receptor–related orphan receptor α (RORα) activator, enhanced the activity of RORα1 and EPO luciferase reporter gene. BavaC treatment also elevated EPO mRNA and protein expression in vitro and in vivo and the circulating EPO levels in rats. By contrast, the RORα antagonist VPR66 inhibited BavaC–induced EPO reporter activity, and differentiation of bone marrow cells into endothelial progenitor cells. Overall, this study revealed that BavaC promotes EPC differentiation and neovascularization through a RORα–EPO–AMPK axis. BavaC can be used as a promising angiogenesis agent for enhancing angiogenesis and tissue repair.

Mitochondrial-Targeted Antioxidant Maintains Blood Flow, Mitochondrial Function, and Redox Balance in Old Mice Following Prolonged Limb Ischemia

Aging is a major factor in the decline of limb blood flow with ischemia. However, the underlying mechanism remains unclear. We investigated the role of mitochondrial reactive oxygen species (ROS) with regard to limb perfusion recovery in aging during ischemia. We performed femoral artery ligation in young and old mice with or without treatment with a scavenger of mitochondrial superoxide, MitoTEMPO (180 μg/kg/day, from pre-operative day 7 to post-operative day (POD) 21) infusion using an implanted mini-pump. The recoveries of cutaneous blood flow in the ischemic hind limb were lower in old mice than in young mice but were improved in MitoTEMPO-treated old mice. Mitochondrial DNA damage appeared in ischemic aged muscles but was eliminated by MitoTEMPO treatment. For POD 2, MitoTEMPO treatment suppressed the expression of p53 and the ratio of Bax/Bcl2 and upregulated the expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in ischemic aged skeletal muscles. For POD 21, MitoTEMPO treatment preserved the expression of PGC-1α in ischemic aged skeletal muscle. The ischemic soleus of old mice showed a lower mitochondrial respiratory control ratio in POD 21 compared to young mice, which was recovered in MitoTEMPO-treated old mice. Scavenging of mitochondrial superoxide attenuated mitochondrial DNA damage and preserved the mitochondrial respiration, in addition to suppression of the expression of p53 and preservation of the expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) in ischemic skeletal muscles with aging. Resolution of excessive mitochondrial superoxide could be an effective therapy to recover blood flow of skeletal muscle during ischemia in senescence.

Endothelial dysfunction and vascular disease - a 30th anniversary update

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H₂ O₂ ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive G_i (e.g. responses to α₂ -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H₂ O₂ ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.

Role of Resveratrol (RES) in Regenerative Medicine

Within the last quarter century, technology has been a major catalyst of the advancement in various fields of scientific knowledge, particularly medical research. This new enlightenment has spurred the exploration of alternative treatment methods to some of society's most problematic diseases. One such innovative treatment is the use of Resveratrol (RES) to treat a number of pathophysiological conditions. RES is a natural polyphenolic compound found in the skin(s) of blueberries, red grapes (a major constituent of red wine), some vegetables, and even peanuts. The compound has a number of potent regenerative properties, which include: anti-aging, anti-inflammatory, and antioxidative. Research has confirmed both in vivo and in vitro RES's beneficial applications to numerous diseases. This chapter centers on its unique healing powers and beneficial applications against myriad debilitating conditions.

EFFECT OF CHRONIC INGESTION OF WINE ON THE GLYCEMIC, LIPID AND BODY WEIGHT HOMEOSTASIS IN MICE

Background

The health benefits associated with moderate wine consumption, as with ethanol and phenolic compounds, include different mechanisms still little understandable.

Aim

Evaluate glycemic and weight variations, and the deposit of triglycerides, cholesterol and liver glycogen with red wine consumption.

Methods

60 ApoE knockout mice were divided into three groups of 20: Wine Group (WG), Ethanol Group (EG) and Water Group (WAG). They received daily: WG 50 ml of wine and 50 ml water; EG 6 ml ethanol and WAG 94 ml of water. All groups were followed for four months. The food intake was monitored daily, in the period from eight to ten hours and held every five days. The measurement of water intake was also made every five days. The weighing of the animals took place every ten days.

Results

The WG had higher weight increase as compared to the other groups. The concentration of hepatic triglyceride was higher in WG (57%) and the EG group was lower (31.6%, p<0.01) than the control. The concentration of cholesterol was lower in the WG (23.6%), as well as EG (24.5%, p<0.05). The concentration of glycogen was higher in WG (16%) and fasting blood glucose was higher in EG compared to the other groups but not both demonstrated a statistically significant difference.

Conclusion

The WG increased triglyceride and WAG decreased cholesterol. The triglyceride may be increased due to the high caloric value of wine or some unknown property that led to significant increase in subcutaneous andretroperitoneal fat in mice.

Senescence marker protein-30 deficiency impairs angiogenesis under ischemia

Aging decreases collateral-dependent flow recovery following acute arterial obstruction. However, the mechanisms are partially understood, therefore critical management has been lacked in clinical setting. Senescence marker protein-30 (SMP30) is a novel aging marker, which is assumed to act as an anti-aging factor in various organs. Therefore, we studied the effect of SMP30 on ischemia-induced collateral growth in SMP30 knockout (KO) mice, young and old C57BL/6 mice. The SMP30 expression in gastrocnemius tissue was decreased in old mice compared to that of young mice. The recovery of cutaneous blood flow in hind limb after femoral artery ligation and tissue capillary density recoveries were suppressed in SMP30 KO and old mice compared to those in young mice. Nitric oxide generation induced by l-arginine and GSH/GSSG in aorta of SMP30 KO and old mice were lower than those in young mice. The levels of NADPH oxidase activity and superoxide production in the ischemic tissue were higher in SMP30 KO and old mice than in young mice. The phosphorylated eNOS and Akt levels and VEGF levels in ischemic muscle were lower in SMP30 KO and old mice than in young mice. Deficiency of SMP30 exacerbates oxidative stress related to NADPH oxidase activity enhancement and impairs eNOS activity, which leads to rarefaction of angiogenesis induced by ischemia. These results suggest that SMP30 plays a key role in disrupting collateral growth under ischemia in aging.

Direct renin inhibition with aliskiren improves ischemia-induced neovascularization: blood pressure-independent effect

BACKGROUND

Renin is the rate limiting step for the activation of the renin-angiotensin-aldosterone system, which is linked to the development of endothelial dysfunction, hypertension and atherosclerosis. However, the specific role of renin during physiological responses to tissue ischemia is currently unknown. Aliskiren is the only direct renin inhibitor that is clinically used as an orally active antihypertensive drug. Here we tested the hypothesis that aliskiren might improve neovascularization in response to ischemia.

METHODS AND RESULTS

At a dose that did not modulate blood pressure (10 mg/kg), aliskiren led to improved blood flow recovery after hindlimb ischemia in C57BL/6 mice (Doppler flow ratios 0.71 ± 0.07 vs. 0.55 ± 0.03; P < 0.05). In ischemic muscles, treatment with aliskiren was associated with a significant increase of vascular density, reduced oxidative stress levels and increased expression of VEGF and eNOS. Aliskiren treatment also significantly increased the number of bone marrow-derived endothelial progenitor cells (EPCs) after hindlimb ischemia. Moreover, the angiogenic properties of EPCs (migration, adhesion, integration into tubules) were significantly improved in mice treated with aliskiren. In vitro, aliskiren improves cellular migration and tubule formation in HUVECs. This is associated with an increased expression of nitric oxide (NO), and a significant reduction of oxidative stress levels. Importantly, the angiogenic properties of aliskiren in vitro and in vivo are completely abolished following treatment with the NOS inhibitor l-NAME.

CONCLUSION

Direct renin inhibition with aliskiren leads to improved ischemia-induced neovascularization that is not dependant on blood pressure lowering. The mechanism involves beneficial effects of aliskiren on oxidative stress and NO angiogenic pathway, together with an increase in the number and the functional activities of EPCs.

ADAM12: a genetic modifier of preclinical peripheral arterial disease

In prior studies from multiple groups, outcomes following experimental peripheral arterial disease (PAD) differed considerably across inbred mouse strains. Similarly, in humans with PAD, disease outcomes differ, even when there are similarities in risk factors, disease anatomy, arteriosclerotic burden, and hemodynamic measures. Previously, we identified a locus on mouse chromosome 7, limb salvage-associated quantitative trait locus 1 (LSq-1), which was sufficient to modify outcomes following experimental PAD. We compared expression of genes within LSq-1 in Balb/c mice, which normally show poor outcomes following experimental PAD, with that in C57Bl/6 mice, which normally show favorable outcomes, and found that a disintegrin and metalloproteinase gene 12 (ADAM12) had the most differential expression. Augmentation of ADAM12 expression in vivo improved outcomes following experimental PAD in Balb/c mice, whereas knockdown of ADAM12 made outcomes worse in C57Bl/6 mice. In vitro, ADAM12 expression modulates endothelial cell proliferation, survival, and angiogenesis in ischemia, and this appeared to be dependent on tyrosine kinase with Ig-like and EGF-like domain 2 (Tie2) activation. ADAM12 is sufficient to modify PAD severity in mice, and this likely occurs through regulation of Tie2.

Psychological stress impairs ischemia-induced neovascularization: Protective effect of fluoxetine

BACKGROUND

Psychological stress (PS) has been associated with the development of cardiovascular diseases and adverse long-term outcomes after ischemic events. However, the precise mechanisms involved are not completely understood. Here we investigated the effect of PS on ischemia-induced neovascularization, and the potential therapeutic effect of fluoxetine in this condition.

METHODS AND RESULTS

Balb/c mice were subjected or not to chronic restraint stress. After 3 weeks, hindlimb ischemia was surgically induced by femoral artery removal. We found that blood flow recovery was significantly impaired in mice exposed to PS compared to controls (Doppler flow ratio (DFR) 0.61 ± 0.07 vs. 0.80 ± 0.07, p < 0.05). At the microvascular level, capillary density was significantly reduced in ischemic muscles of mice exposed to PS (38 ± 1 vs. 74 ± 3 capillaries per field, p < 0.001). This correlated with increased oxidative stress levels and reduced expression of VEGF and VEGF signalling molecules (p44/p42 MAPK, Akt) in ischemic muscles. We found that the number of pro-angiogenic cells (PACs) was significantly reduced in mice exposed to PS. In addition, oxidative stress levels (DCF-DA, DHE) were increased in PACs isolated from mice exposed to PS, and this was associated with impaired PAC functional activities (migration, adhesion, and integration into tubules). Importantly, treatment of mice exposed to PS with the selective serotonin reuptake inhibitor (SSRI) fluoxetine improved all the angiogenic parameters, and completely rescued PS-induced impairment of neovascularization.

CONCLUSION

PS impairs ischemia-induced neovascularization. Potential mechanisms involved include reduced activation of the VEGF pathway in ischemic tissues, increased oxidative stress levels and reduced number and functional activities of PACs. Our results suggest that fluoxetine may represent a novel therapeutic strategy to improve neovascularization and reduce ischemia in patients suffering from cardiovascular diseases and exposed to PS.

Therapeutic potential of ixmyelocel-T, an expanded autologous multicellular therapy for treatment of ischemic cardiovascular diseases

INTRODUCTION

Bone marrow derived cellular therapies are an emerging approach to promoting therapeutic angiogenesis in ischemic cardiovascular disease. However, the percentage of regenerative cells in bone marrow mononuclear cells (BMMNCs) is small, and large amounts of BMMNCs are required. Ixmyelocel-T, an expanded autologous multicellular therapy, is manufactured from a small sample of bone marrow aspirate. Ixmyelocel-T contains expanded populations of mesenchymal stromal cells (MSCs) and M2-like macrophages, as well as many of the CD45+ cells found in the bone marrow. It is hypothesized that this expanded multi-cellular therapy would induce angiogenesis and endothelial repair.

METHODS

A rat model of hind limb ischemia was used to determine the effects of ixmyelocel-T on blood flow recovery. To further determine the effects on endothelial cells, ixmyelocel-T was co-cultured with human umbilical vein endothelial cells (HUVEC) in non-contacting Transwell® inserts.

RESULTS

Co-culture of HUVECs with ixmyelocel-T resulted secretion of a variety of pro-angiogenic factors. HUVECs stimulated by ixmyelocel-T exhibited enhanced migration, proliferation, and branch formation. Ixmyelocel-T co-culture also resulted in increased endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production. In tumor necrosis factor alpha (TNFα)-stimulated HUVECs, ixmyelocel-T co-culture decreased apoptosis and reactive oxygen species generation, increased super oxide dismutase activity, and decreased nuclear factor kappa B (NFκB) activation. Treatment with ixmyelocel-T in a rat model of hind limb ischemia resulted in significantly increased blood flow perfusion and capillary density, gene expression and plasma levels of the anti-inflammatory cytokine interleukin (IL)-10, plasma nitrates, plasma platelet-derived growth factor (PDGF)-BB, vascular endothelial growth factor (VEGF) expression, and significantly decreased plasma thiobarbituric acid reactive substances (TBARS).

CONCLUSIONS

This work demonstrates that ixmyelocel-T interacts with endothelial cells in a paracrine manner, resulting in angiogenesis and endothelial protection. This data suggests that ixmyelocel-T could be useful for promoting of angiogenesis and tissue repair in ischemic cardiovascular diseases. In conclusion, ixmyelocel-T therapy may provide a new aspect of therapeutic angiogenesis in this patient population where expanded populations of regenerative cells might be required.

Resveratrol alters human endothelial cells redox state and causes mitochondrial-dependent cell death

Studies analyzing the impact of natural antioxidants (NA) on Endothelial Cells (ECs) have dramatically increased during the last years, since a deregulated ECs redox state is at the base of the onset and progression of several cardiovascular diseases. However, whether NA can provide cardiovascular benefits is still a controversial area of debate. Resveratrol (RES), a natural polyphenol found in grapes, is believed to provide cardiovascular benefits by virtue of its antioxidant effect on the endothelium. Here, we report that tissue-attainable doses of resveratrol increased the intracellular oxidative state, thus affecting mitochondrial membrane depolarization and inducing EC death. Cyclosporine A, a mitochondrial permeability transition pore inhibitor, prevented oxidative-mediated cell death, thus implicating mitochondria in resveratrol-induced EC impairment. The specific cytochrome P450 (CYP) 2C9 inhibitor, sulfaphenazole, counteracted both oxidative stress and mitochondrial membrane depolarization, providing EC protection against resveratrol-elicited pro-oxidant effects. Our findings strongly suggest that CYP2C9 mediates resveratrol-induced oxidative stress leading to mitochondria impairment and EC death.

Secretoneurin gene therapy improves hind limb and cardiac ischaemia in Apo E⁻/⁻ mice without influencing systemic atherosclerosis

AIMS

Hypercholesterolaemia is a major risk factor for cardiovascular diseases and has been shown to influence angiogenesis in the hind limb ischaemia (HLI) model. The impaired up-regulation of angiogenic factors seems to be one of the underlying mechanisms for reduced vessel formation. Since we found that secretoneurin (SN) is up-regulated in hypoxic skeletal muscle cells and exerts beneficial effects in myocardial and HLI, we hypothesized that SN therapy might improve neovascularization in hypercholesterolaemic Apo E(-/-) (Apo E knockout) mice suffering from an impaired vascular response.

METHODS AND RESULTS

For in vitro experiments, endothelial cells (ECs) were incubated with oxidized low-density lipoprotein (oxLDL) to mimic hypercholesterolaemia. EC function was impaired by oxLDL, but SN induced EC proliferation and in vitro tube formation under these conditions. In the HLI model, injection of SN plasmid resulted in a significant better outcome regarding blood flow recovery, amputation rate, and vessel density. In the myocardial infarction (MI) model, the SN group showed improvement in cardiac parameters. Aortic plaque area was not influenced by local SN injection. Interestingly, SN-induced recruitment of angiogenic monocytic cells was abolished under hypercholesterolaemia.

CONCLUSIONS

SN gene therapy exerts beneficial effects in cardiovascular animal models in Apo E(-/-) mice without influencing atherosclerosis and might qualify as a promising therapy for cardiovascular disorders.

Resveratrol and endothelial nitric oxide

Nitric oxide (NO) derived from the endothelial NO synthase (eNOS) has antihypertensive, antithrombotic, anti-atherosclerotic and antiobesogenic properties. Resveratrol is a polyphenol phytoalexin with multiple cardiovascular and metabolic effects. Part of the beneficial effects of resveratrol are mediated by eNOS. Resveratrol stimulates NO production from eNOS by a number of mechanisms, including upregulation of eNOS expression, stimulation of eNOS enzymatic activity and reversal of eNOS uncoupling. In addition, by reducing oxidative stress, resveratrol prevents oxidative NO inactivation by superoxide thereby enhancing NO bioavailability. Molecular pathways underlying these effects of resveratrol involve SIRT1, AMPK, Nrf2 and estrogen receptors.

Echinocystic acid, isolated from Gleditsia sinensis fruit, protects endothelial progenitor cells from damage caused by oxLDL via the Akt/eNOS pathway

AIMS

Our previous studies revealed that echinocystic acid (EA) showed obvious attenuation of atherosclerosis in rabbits fed a high-fat diet. However, the underlying mechanisms remain to be elucidated. Considering the importance of endothelial progenitor cells (EPCs) in atherosclerosis, we hypothesise that EPCs may be one of the targets for the anti-atherosclerotic potential of EA.

MAIN METHODS

After in vitro cultivation, EPCs were exposed to 100 μg/mL of oxidised low-density lipoprotein (oxLDL) and incubated with or without EA (5 and 20 μM) for 48 h. An additional two groups of EPCs (oxLDL+20 μM EA) were pre-treated with either wortmannin, an inhibitor of the phosphoinositide 3-kinase (PI3K) pathway, or nitro-l-arginine methyl ester (l-NAME), an endothelial nitric oxide synthase (eNOS)-specific inhibitor. Assessment of EPC apoptosis, adhesion, migration, and nitric oxide (NO) release was performed using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) staining, cell counting, caspase-3 activity assay, transwell chamber assay, and Griess reagent, respectively. The protein expression of protein kinase B (Akt) and eNOS was detected using Western blot.

KEY FINDINGS

Treatment of EPCs with oxLDL induced significant apoptosis and impaired adhesion, migration, and NO production. The deleterious effects of oxLDL on EPCs were attenuated by EA. However, when EPCs were pre-treated with wortmannin or l-NAME, the effects of EA were abrogated. Additionally, oxLDL significantly down-regulated eNOS protein expression as well as repression of eNOS and Akt phosphorylation.

SIGNIFICANCE

The inhibitory effect of oxLDL on Akt/eNOS phosphorylation was attenuated by EA. Taken together, the results indicate that EA protects EPCs from damage caused by oxLDL via the Akt/eNOS pathway.

Coumaric acid induces mitochondrial damage and oxidative-mediated cell death of human endothelial cells

Evidence that higher natural antioxidants (NA) intake provides cardiovascular protection is contradictory. The endothelium plays a pivotal role in cardiovascular homeostasis, and for this reason, the molecular events resulting from the interaction of NA with endothelial cells (ECs) are actively investigated. Here, we show that moderately high doses of coumaric acid (CA) induced intracellular reactive oxygen species (ROS) production, mitochondrial membrane depolarization and ECs death. Treatment of ECs with cyclosporine A, a mitochondrial permeability transition pore inhibitor, prevented the oxidative-mediated cell damage indicating mitochondrial involvement in CA-induced ECs impairment. CA-induced intracellular ROS generation was counteracted by the specific cytochrome P450 (CYP) 2C9 inhibitor sulfaphenazole (SPZ). SPZ also prevented CA-induced mitochondrial membrane depolarization and ECs death, implicating CYP2C9 in mediating the cellular response upon CA treatment. Our results indicate that moderately high doses of CA can promote CYP2C9-mediated oxidative stress eliciting mitochondrial-dependent ECs death and may pave the way toward mechanistic insight into NA effects on cardiovascular cells.

Endothelium and its alterations in cardiovascular diseases: life style intervention

The endothelium, which forms the inner cellular lining of blood vessels and lymphatics, is a highly metabolically active organ that is involved in many physiopathological processes, including the control of vasomotor tone, barrier function, leukocyte adhesion, and trafficking and inflammation. In this review, we summarized and described the following: (i) endothelial cell function in physiological conditions and (ii) endothelial cell activation and dysfunction in the main cardiovascular diseases (such as atherosclerosis, and hypertension) and to diabetes, cigarette smoking, and aging physiological process. Finally, we presented the currently available evidence that supports the beneficial effects of physical activity and various dietary compounds on endothelial functions.

Fish oil-enriched diet protects against ischemia by improving angiogenesis, endothelial progenitor cell function and postnatal neovascularization

BACKGROUND

Fish oil consumption has been associated with a reduced incidence of cardiovascular diseases. However, the precise mechanisms involved are not completely understood. Here we tested the hypothesis that a fish oil-enriched diet improves neovascularization in response to ischemia.

METHODS AND RESULTS

C57Bl/6 mice were fed a diet containing either 20% fish oil, rich in long-chain n-3 polyunsaturated fatty acids (PUFAs), or 20% corn oil, rich in n-6 PUFAs. After 4 weeks, hindlimb ischemia was surgically induced by femoral artery removal. We found that blood flow recovery was significantly improved in mice fed a fish oil diet compared to those fed a corn oil diet (Doppler flow ratio (DFR) at day 21 after surgery 78 ± 5 vs. 56 ± 4; p < 0.01). Clinically, this was associated with a significant reduction of ambulatory impairment and ischemic damage in the fish oil group. At the microvascular level, capillary density was significantly improved in ischemic muscles of mice fed a fish oil diet. This correlated with increased expression of VEGF and eNOS in ischemic muscles, and higher NO concentration in the plasma. Endothelial progenitor cells (EPCs) have been shown to have an important role for postnatal neovascularization. We found that the number of EPCs was significantly increased in mice fed a fish oil diet. In addition, oxidative stress levels (DCF-DA, DHE) were reduced in EPCs isolated from mice exposed to fish oil, and this was associated with improved EPC functional activities (migration and integration into tubules). In vitro, treatment of EPCs with fish oil resulted in a significant increase of cellular migration. In addition, the secretion of angiogenic growth factors including IL6 and leptin was significantly increased in EPCs exposed to fish oil.

CONCLUSION

Fish oil-enriched diet is associated with improved neovascularization in response to ischemia. Potential mechanisms involved include activation of VEGF/NO pathway in ischemic tissues together with an increase in the number and the functional activities of EPCs.

A newly synthesized sinapic acid derivative inhibits endothelial activation in vitro and in vivo

Inhibition of oxidative stress and inflammation in vascular endothelial cells (ECs) may represent a new therapeutic strategy against endothelial activation. Sinapic acid (SA), a phenylpropanoid compound, is found in natural herbs and high-bran cereals and has moderate antioxidant activity. We aimed to develop new SA agents with the properties of antioxidation and blocking EC activation for possible therapy of cardiovascular disease. We designed and synthesized 10 SA derivatives according to their chemical structures. Preliminary screening of the compounds involved scavenging hydroxyl radicals and 2,2-diphenyl-1-picrylhydrazyl (DPPH(⋅)), croton oil-induced ear edema in mice, and analysis of the mRNA expression of adhesion molecules in ECs. 1-Acetyl-sinapic acyl-4-(3'-chlorine-)benzylpiperazine (SA9) had the strongest antioxidant and anti-inflammatory activities both in vitro and in vivo. Thus, the effect of SA9 was further studied. SA9 inhibited tumor necrosis factor α-induced upregulation of adhesion molecules in ECs at both mRNA and protein levels, as well as the consequent monocyte adhesion to ECs. In vivo, result of face-to-face immunostaining showed that SA9 reduced lipopolysaccharide-induced expression of intercellular adhesion molecule-1 in mouse aortic intima. To study the molecular mechanism, results from luciferase assay, nuclear translocation of NF-κB, and Western blot indicated that the mechanism of the anti-inflammatory effects of SA9 might be suppression of intracellular generation of ROS and inhibition of NF-κB activation in ECs. SA9 is a prototype of a novel class of antioxidant with anti-inflammatory effects in ECs. It may represent a new therapeutic approach for preventing endothelial activation in cardiovascular disorders.

Endothelial progenitor cell dysfunction in cardiovascular diseases: role of reactive oxygen species and inflammation

Endothelial progenitor cells (EPCs) move towards injured endothelium or inflamed tissues and incorporate into foci of neovascularisation, thereby improving blood flow and tissue repair. Patients with cardiovascular diseases have been shown to exhibit reduced EPC number and function. It has become increasingly apparent that these changes may be effected in response to enhanced oxidative stress, possibly as a result of systemic and localised inflammatory responses. The interplay between inflammation and oxidative stress affects the initiation, progression, and complications of cardiovascular diseases. Recent studies suggest that inflammation and oxidative stress modulate EPC bioactivity. Clinical medications with anti-inflammatory and antioxidant properties, such as statins, thiazolidinediones, angiotensin II receptor 1 blockers, and angiotensin-converting enzyme inhibitors, are currently administered to patients with cardiovascular diseases. These medications appear to exert beneficial effects on EPC biology. This review focuses on EPC biology and explores the links between oxidative stress, inflammation, and development of cardiovascular diseases.

Resveratrol: French paradox revisited

Resveratrol is a polyphenol that plays a potentially important role in many disorders and has been studied in different diseases. The research on this chemical started through the “French paradox,” which describes improved cardiovascular outcomes despite a high-fat diet in French people. Since then, resveratrol has been broadly studied and shown to have antioxidant, anti-inflammatory, anti-proliferative, and anti-angiogenic effects, with those on oxidative stress possibly being most important and underlying some of the others, but many signaling pathways are among the molecular targets of resveratrol. In concert they may be beneficial in many disorders, particularly in diseases where oxidative stress plays an important role. The main focus of this review will be the pathways affected by resveratrol. Based on these mechanistic considerations, the involvement of resveratrol especially in cardiovascular diseases, cancer, neurodegenerative diseases, and possibly in longevity will be is addressed.

Alcohol and cardiovascular disease--modulation of vascular cell function

Alcohol is a commonly used drug worldwide. Epidemiological studies have identified alcohol consumption as a factor that may either positively or negatively influence many diseases including cardiovascular disease, certain cancers and dementia. Often there seems to be a differential effect of various drinking patterns, with frequent moderate consumption of alcohol being salutary and binge drinking or chronic abuse being deleterious to one’s health. A better understanding of the cellular and molecular mechanisms mediating the many effects of alcohol consumption is beginning to emerge, as well as a clearer picture as to whether these effects are due to the direct actions of alcohol itself, or caused in part by its metabolites, e.g., acetaldehyde, or by incidental components present in the alcoholic beverage (e.g., polyphenols in red wine). This review will discuss evidence to date as to how alcohol (ethanol) might affect atherosclerosis that underlies cardiovascular and cerebrovascular disease, and the putative mechanisms involved, focusing on vascular endothelial and smooth muscle cell effects.

Inhibitory effects of balsamic vinegar on LDL oxidation and lipid accumulation in THP-1 macrophages

Oxidized low-density lipoprotein (LDL) is believed to contribute to atherosclerosis in part by being taken up into macrophages via scavenger receptors, thus accounting for foam cells. Balsamic vinegar is made from grapes and generally consumed in the Mediterranean region. In this study, we investigated the preventive effects of balsamic vinegar on LDL oxidation and foam cell formation. Balsamic vinegar had stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging abilities and higher polyphenol concentrations than rice vinegar. Balsamic vinegar dramatically inhibited LDL oxidation by azoradicals and endothelial cell-mediated oxidation in vitro. Further, we assessed the anti-oxidative effect against LDL after balsamic vinegar consumption in human subjects. Balsamic vinegar prolonged the LDL oxidation lag time and decreased lipid peroxide (LPO) and lyso-phosphatidylcholine (LPC) in LDL particles. We next examined the effect of balsamic vinegar on foam cell formation. Oil red O staining showed that balsamic vinegar inhibited oxidized LDL-induced foam cell formation in THP-1 macrophages. The concentrations of intracellular triglycerides and total cholesterols were reduced in the presence of balsamic vinegar. In addition, balsamic vinegar decreased the mRNA and protein expression level of scavenger receptors in THP-1 macrophages. These results showed that balsamic vinegar contained abundant polyphenols and inhibited LDL oxidation and oxidized LDL-induced foam cell formation by decreasing the expression of scavenger receptors.

Red grape skin and seeds polyphenols: Evidence of their protective effects on endothelial progenitor cells and improvement of their intestinal absorption

SCOPE

To evaluate the ability of grape skin and seeds to protect endothelial progenitor cells (EPC) from oxidative stress induced by hyperglycemia (HG) compared to red wine (RW) and prepare innovative pharmaceutical systems for the oral administration of red grape extract allowing the overcoming of its poor intestinal absorption.

METHODS AND RESULTS

Human EPC were characterized by expression of cell surface markers. Cells were incubated with different concentrations of total polyphenols from grape components or RW in the presence or absence of HG. Cell viability, migration, adhesion, and reactive oxygen species (ROS) production were assayed. Intestinal permeation of polyphenols was studied in the absence or presence of a quaternary ammonium-chitosan conjugate (N⁺(60)-Ch). Grape components and RW increased EPC viability, adhesion and migration, and prevented the HG effect (P < 0.01). ROS production induced by HG was significantly reduced only by grape seed extract and RW (P < 0.01). N⁺(60)-Ch acted as an effective enhancer of polyphenol permeability across the excised rat intestine.

CONCLUSIONS

Red grape components are a source of antioxidant compounds that ameliorate EPC viability and function, while preventing endothelial dysfunction. The use of polycationic chitosan derivatives can promote the absorption of polyphenols across intestinal epithelium, thus increasing their bioavailability and potential therapeutic value in atherosclerosis.

Nox2-derived reactive oxygen species contribute to hypercholesterolemia-induced inhibition of neovascularization: effects on endothelial progenitor cells and mature endothelial cells

BACKGROUND

Hypercholesterolemia has been associated with impaired angiogenesis and reduced blood flow recuperation after ischemia. However, the precise mechanisms involved are unknown. Here we investigated the role of Nox2-derived reactive oxygen species (ROS) in the modulation of neovascularization by hypercholesterolemia.

METHODS AND RESULTS

Mice deficient for the Nox2-containing NADPH oxidase (Nox2(-/-)) and control mice (Nox2(+/+)) were put on a high cholesterol diet (HCD) for a total of 15 weeks. After three months, hindlimb ischemia was surgically induced by femoral artery removal. Nox2 expression and oxidative stress levels in ischemic tissues were significantly increased by HCD in control mice, but not in Nox2(-/-) mice. Nox2(-/-) mice were also protected against hypercholesterolemia-induced impairment of neovascularization, as demonstrated by faster blood flow recovery after ischemia and increased capillary density in ischemic muscles. Nox2 deficiency was associated with preserved activity of eNOS in ischemic tissues, and improved activity of endothelial progenitor cells (EPCs). In vitro, HUVECs treated with the NADPH oxidase inhibitor apocynin or endothelial cells isolated from the aorta of Nox2(-/-) mice exhibited reduced ROS formation following exposure to oxLDL. This was associated with improved nitric oxide (NO) bioavailability and protection against oxLDL-induced inhibition of angiogenic activities.

CONCLUSIONS

Nox2-containing NADPH oxidase deficiency protects against hypercholesterolemia-induced impairment of neovascularization. The potential mechanisms involved include reduced ROS formation, preserved activation of angiogenic signals, and improved functional activities of EPCs and mature endothelial cells.

Should Red Wine Be Considered a Functional Food?

  Functional foods may be regarded as foods that have nutritional value, but in particular, they also have beneficial effects on one or more body functions. Thus, functional foods may improve health and/or reduce the risk of developing certain diseases when taken in amounts that can be consumed in a normal diet. Based on nearly 2 decades of research since the term "French paradox" was first coined in 1992, wine would appear to fit this definition. Yet there seems to be reluctance to consider wine as a functional food. In this review, we present an overview of the accumulated evidence for the health benefits of wine-and its key phenolic components such as resveratrol, quercetin, catechin-and show that these alone are not enough to firmly establish wine as a functional food. What is required is to create clearly defined products based on wine that are targeted to consumers' needs and expectations when it comes to purchasing functional foods. Moreover, the crucial question of alcohol and health also needs to be addressed by the functional food industry. Suggestions are presented for working through this issue, but in many regards, wine is like any other food-it should be consumed sensibly and in amounts that are beneficial to health. Overindulgence of any kind does not promote good health.

Red wine consumption improves in vitro migration of endothelial progenitor cells in young, healthy individuals

BACKGROUND

Endothelial progenitor cells (EPCs) contribute to the maintenance of vascular endothelial function. The moderate consumption of red wine provides cardiovascular protection.

OBJECTIVE

We investigated the underlying molecular mechanism of EPC migration in young, healthy individuals who drank red wine.

DESIGN

Fourteen healthy volunteers consumed 250 mL red wine daily for 21 consecutive days. Vascular endothelial function, plasma stromal cell-derived factor 1alpha (SDF1alpha) concentrations, and the number, migration, and nitric oxide production of EPCs were determined before and after the daily consumption of red wine. EPCs were glucose stressed to study the effect of red wine on EPC migration, proliferation, and senescence and to study the expressions of CXC chemokine receptor 4 (CXCR4) and members of the Pi3K/Akt/eNOS (phosphatidylinositol 3-kinase/protein kinase B/endothelial nitric oxide synthase) signaling pathway by Western blotting.

RESULTS

Daily red wine consumption for 21 consecutive days significantly enhanced vascular endothelial function. Although plasma SDF1alpha concentrations were unchanged, EPC count and migration were significantly increased after this 21-d consumption period. Red wine increased the migration, proliferation, CXCR4 expression, and activity of the Pi3K/Akt/eNOS signaling pathway and decreased the extent of apoptosis in glucose-stressed EPCs.

CONCLUSIONS

The results of the present study indicate that red wine exerts its effect through the up-regulation of CXCR4 expression and activation of the SDF1alpha/CXCR4/Pi3K/Akt/eNOS signaling pathway, which results in increased EPC migration and proliferation and decreased extent of apoptosis. Our findings suggest that these effects could be linked to the mechanism of cardiovascular protection that is associated with the regular consumption of red wine.

Protection against severe intestinal ischemia/reperfusion injury in rats by intravenous resveratrol

BACKGROUND

Repetitive enteral or intraperitoneal administration of resveratrol at high doses has recently been found to protect the small intestine against acute ischemia/reperfusion (I/R) injury. In the present work, the protective potential of solvent-free continuous intravenous infusions of small amounts of resveratrol was studied in a model of severe intestinal I/R injury.

MATERIALS AND METHODS

Mesenteric ischemia was induced in male Wistar rats (six animals/group) by superior mesenteric artery occlusion (SMAO, 90 min) and reperfusion (120 min) by reopening of the microvascular clamp. Resveratrol (0.056 or 0.28 mg/kg) was continuously perfused into the jugular vein (0.014 or 0.07 mg/kg × h) starting 30 min before SMAO; an SMAO control group and sham groups (no SMAO) receiving either 0.9% NaCl solution or resveratrol (0.28 mg/kg) were included. During the experimental procedure, isotonic saline was given at a systolic blood pressure below 90 mmHg, and several parameters including those of biomonitoring and blood gas analysis were measured. Small intestine injury was assessed macroscopically, from released plasma enzyme activities, from the tissue contents of thiobarbituric acid-reactive substances and hemoglobin, from the tissue myeloperoxidase activity, and histopathologically.

RESULTS

Resveratrol at only 0.056 mg/kg significantly decreased the macroscopic damage score, the tissue myeloperoxidase activity, the hemoglobin content, the histopathologic score, and the plasma glutamate-pyruvate transaminase activity, but it did not improve the systemic and metabolic parameters. Instead, during reperfusion, significantly higher volumes of saline were administered to animals receiving the polyphenol, although resveratrol did not significantly affect any parameters in sham-operated animals.

CONCLUSIONS

Low doses of intravenously administered resveratrol considerably protected the rat small intestine against severe I/R injury, despite some adverse effects on blood pressure under these conditions.

Antioxidants: benefits and risks for long-term health

The oxidative modification hypothesis postulates that oxidative stress is one of the major factors in aging and the development of age-related disorders, including cardiovascular diseases. In this scenario, the oxidative modification of lipids, proteins and nucleic acids in vascular walls contributes to the etiology of cardiovascular disease, implying that consumption or therapeutic use of antioxidants could prevent the onset of such pathological disorders. Because of this, a number of studies have been conducted to address the question of whether cardiovascular diseases can be modulated by antioxidant treatment or consumption. Although some of the earliest data, collected in animal studies and epidemiologic studies have shown a measure of success, numerous clinical trials indicate that this approach is of minimal or no benefit. These conclusions represent a challenge to design more sensitive antioxidant trials in order to confirm or alter these conclusions. The focus of this review is on the benefits and disadvantages associated with the use of antioxidants, such as vitamins C and E, polyphenols, or antioxidant therapies, including hormone replacement therapy and iron reduction therapy, on overall vascular health.

HDL cholesterol is a strong determinant of endothelial progenitor cells in hypercholesterolemic subjects

Endothelial progenitor cells (EPC) can repair the endothelial layer and are considered a component of the cardiovascular system. EPC number and function may change under pathological conditions, including cardiovascular risk factors. The study was carried out to investigate circulating EPC number, in vitro function and relationship with LDL-C, HDL-C and endothelium-dependent vasodilatation in hypercholesterolemic subjects. Forty-one male and 39 female subjects, age>35 and<45, LDL cholesterol plasma level>130 mg/dl with normal (> or =50 mg/dl females and> or =40 mg/dl males) or low HDL-C, absence of any concomitant disorders and/or drug treatment, at their first diagnosis of hypercholesterolemia, were consecutively recruited in the Outpatient Service of the Medical Pathophysiology Department of Rome Sapienza University. In high LDL-C patients, circulating EPC number was decreased and EPC capability to migrate was impaired as well. This pattern was far less evident in the normal HDL-C subgroup. The endothelium-dependent vasodilatation (EDV) was significantly decreased according to the HDL-C decrease in male but not in female subjects. Univariate analysis showed a direct correlation between EPC number and EDV, and the association persisted after adjustment for sex, age and HDL-C, which were all significantly correlated to EDV, which may suggest a protective role of EPC on endothelium in vivo. Our study documented that, in hypercholesterolemic subjects, HDL-C is a strong determinant of EPC number and function, and EPC number decrease is an independent risk factor for endothelial dysfunction.

Current perspective of pathophysiological and interventional effects on endothelial progenitor cell biology: focus on PI3K/AKT/eNOS pathway

For more than a decade, endothelial progenitor cells (EPCs) have been implicated in cardiovascular homeostasis. EPCs are believed to reside within the bone marrow in close contact with surrounding stromal cells, and, under stimulation of pro-inflammatory cytokines, EPCs are mobilized out of the bone marrow. Hereafter circulating EPCs home to peripheral tissues, undergoing further proliferation and differentiation. Under certain pathophysiologic conditions this process seems to be blunted, resulting in a reduced capacity of EPCs to engage in vasculogenesis at sites of endothelial injury or tissue ischemia. In this review, we focus on the effects of traditional cardiovascular risk factors on EPC biology and we explore whether pharmacological, dietary and lifestyle interventions can favorably restore EPC mobilization, differentiation, homing and angiogenic properties. Because the PI3K/Akt/eNOS pathway plays a pivotal role in the process of EPC mobilization, migration and homing, we specifically emphasize the involvement of PI3K, Akt and eNOS in EPC biology under these different (patho)physiologic conditions. (Pre)clinically used drugs or lifestyle interventions that have been shown to ameliorate EPC biology are reviewed. These treatment strategies remain attractive targets to restore the regenerative capacity of EPCs in cardiovascular diseases.

Oxidized low-density lipoprotein induces apoptosis in endothelial progenitor cells by inactivating the phosphoinositide 3-kinase/Akt pathway

We tested the hypothesis that oxidized low-density lipoprotein (oxLDL)-induced inactivation of Akt within endothelial progenitor cells (EPCs) is mediated at the level of phosphoinositide 3-kinase (PI3K), specifically by nitrosylation of the p85 subunit of PI3K, and that this action is critical in provoking oxLDL-induced EPC apoptosis. Hypercholesterolemic ApoE null mice had a significant reduction of the phosphorylated Akt (p-Akt)/Akt ratio in EPCs, as well as a greater percentage of apoptosis in these cells than EPCs isolated from wild-type (WT) C57Bl/6 mice. EPCs were isolated from WT spleen and exposed to oxLDL in vitro. oxLDL increased O₂⁻ and H₂O₂ in these cells and induced a dose- and time-dependent reduction in the p-Akt/Akt ratio and increase in EPC apoptosis. These effects were significantly reduced by the antioxidants superoxide dismutase, L-NAME, epicatechin and FeTPPs. oxLDL also induced nitrosylation of the p85 subunit of PI3K and subsequent dissociation of the p85 and p110 subunits, an effect significantly reduced by all the antioxidant agents tested. EPC transfection with a constitutively active Akt isoform (Ad-myrAkt) significantly reduced oxLDL-induced apoptosis of WT EPCs. The present findings indicate that oxLDL disrupts the PI3K/Akt signaling pathway at the level of p85 in EPCs. This dysfunction can be reversed by ex vivo antioxidant therapy.

Intake of Red Wine Increases the Number and Functional Capacity of Circulating Endothelial Progenitor Cells by Enhancing Nitric Oxide Bioavailability

Objective— Red wine (RW) consumption has been associated with a reduction of cardiovascular events, but limited data are available on potential mediating mechanisms. This study tested the hypothesis that intake of RW may promote the circulating endothelial progenitor cell (EPC) level and function through enhancement of nitric oxide bioavailability.

Methods and Results— Eighty healthy, young subjects were randomized and assigned to consume water (100 mL), RW (100 mL), beer (250 mL), or vodka (30 mL) daily for 3 weeks. Flow cytometry was used to quantify circulating EPC numbers, and in vitro assays were used to evaluate EPC functions. After RW ingestion, endothelial function determined by flow-mediated vasodilation was significantly enhanced; however, it remained unchanged after water, beer, or vodka intake. There were significantly increased numbers of circulating EPC (defined as KDR + CD133 + , CD34 + CD133 + , CD34 + KDR + ) and EPC colony-forming units only in the RW group (all P <0.05). Only RW ingestion significantly enhanced plasma levels of nitric oxide and decreased asymmetrical dimethylarginine (both P <0.01). Incubation of EPC with RW (but not beer or ethanol) and resveratrol in vitro attenuated tumor necrosis factor-α–induced EPC senescence and improved tumor necrosis factor-α–suppressed EPC functions and tube formation. Incubation with nitric oxide donor sodium nitroprusside significantly ameliorated the inhibition of tumor necrosis factor-α on EPC proliferation, but incubation with endothelial nitric oxide synthase inhibitor l -NAME and PI3K inhibitor markedly attenuated the effect of RW on EPC proliferation.

Conclusion— The intake of RW significantly enhanced circulating EPC levels and improved EPC functions by modifying nitric oxide bioavailability. These findings may help explain the beneficial effects of RW on the cardiovascular system. This study demonstrated that a moderate intake of RW can enhance circulating levels of EPC in healthy subjects by increasing nitric oxide availability. Direct incubation of EPC with RW and resveratrol can modify the functions of EPC, including attenuation of senescence and promotion of EPC adhesion, migration, and tube formation. These data suggest that RW ingestion may alter the biology of EPC, and these alterations may contribute to its unique cardiovascular-protective effect.

Chinese yellow wine and red wine inhibit matrix metalloproteinase-2 and improve atherosclerotic plaque in LDL receptor knockout mice

Our previous study found that Chinese yellow wine could inhibit the production of homocysteine (HCY) induced extracellular matrix metalloproteinase-2 (MMP-2) in the cultured rat vascular smooth muscle cells. Little is known about the relationship between Chinese yellow wine and atherosclerosis or MMP-2 in vivo. Thirty-two LDL Receptor knockout mice on a high-fat and L-methionine diet developed plasma hyperhomocysteinemia and atherosclerosis. They were randomly divided into yellow wine group (n = 8), red wine group (n = 8), ethanol group (n = 8), and control group (n = 8), they were sacrificed after 14 weeks. There were no significant differences with plasma total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels in the four groups. Plasma HCY was significantly decreased in the yellow wine group compared to the other three groups (P < 0.01). Yellow wine and red wine groups significantly reduced the atherosclerosis lesion area compared to ethanol and control groups (P < 0.001). However, there was no significant discrepancy between the yellow wine group and red wine group. Compared to the control group and ethanol group, the production of MMP-2 reduced 26.8% and 23.6% in the aortic sinus and the activation of MMP-2 reduced 32.6% and 27.3% in the aortic arch in the yellow wine group; the production of MMP-2 reduced 25.7% and 22.4% in the aortic sinus and the activation of MMP-2 reduced 30.2% and 26.6% in the aortic arch in the red wine group. These results suggest that Chinese yellow wine and red wine can inhibit MMP-2 and improve atherosclerosis, and maybe both Chinese yellow wine and red wine have beneficial effects on cardiovascular disease by inhibiting MMP-2.

Consuming a diet supplemented with resveratrol reduced infection-related neuroinflammation and deficits in working memory in aged mice

Aged mice treated peripherally with lipopolysaccharide (LPS) show an exaggerated neuroinflammatory response and cognitive deficits compared to adults. Considerable evidence suggests resveratrol, a polyphenol found in red grapes, has potent antiinflammatory effects in the periphery, but its effects on the central inflammatory response and cognitive behavior are unknown. Therefore, the current study investigated if resveratrol dietary supplementation would inhibit neuroinflammation as well as behavioral and cognitive deficits in aged mice given LPS to mimic a peripheral infection. In initial studies, adult (3-6 months) and aged (22-24 months) mice were provided control or resveratrol-supplemented diet for 4 weeks and then injected intraperitoneally (i.p.) with saline or LPS, and locomotor activity and spatial working memory were assessed. As anticipated, deficits in locomotor activity and spatial working memory indicated aged mice are more sensitive to LPS compared to adults. More importantly, the LPS-induced deficits in aged animals were mitigated by dietary supplementation of resveratrol. In addition, resveratrol consumption reduced LPS-induced interleukin-1beta (IL-1beta) in plasma and the IL-1beta mRNA in the hippocampus of aged mice. Finally, pretreatment of BV-2 microglial cells with resveratrol potently inhibited LPS-induced IL-1beta production. These data show that aged mice are more sensitive than adult mice to both the inflammatory and cognitive effects of peripheral immune stimulation and suggest that resveratrol may be useful for attenuating acute cognitive disorders in elderly individuals with an infection.

Probucol and antioxidant vitamins rescue ischemia-induced neovascularization in mice exposed to cigarette smoke: potential role of endothelial progenitor cells

OBJECTIVE

Cigarette smoking is associated with impaired neovascularization in response to ischemia. Potential mechanisms include increased generation of reactive oxygen species (ROS) and a reduction in the function of endothelial progenitor cells (EPCs). Here we tested the hypothesis that antioxidant therapies could stimulate EPC function and improve ischemia-induced neovascularization following cigarette smoke exposure.

METHODS AND RESULTS

C57Bl/6 mice exposed to cigarette smoke (MES) were fed a normal diet (controls) or a diet supplemented with probucol (0.5%) or a combination of vitamin C (25 g/l in drinking water) and vitamin E (0.1% in normal chow). After two weeks of treatment, hindlimb ischemia was surgically induced by femoral artery removal. Exposure to cigarette smoke was associated with a significant reduction of blood flow recuperation and vessel density in ischemic muscles. However, a complete rescue of neovascularization was demonstrated in MES treated with probucol or antioxidant vitamins. We found that antioxidant therapy in MES is associated with a significant reduction of oxidative stress levels both in the plasma and in ischemic muscles. Moreover, EPCs exposed to cigarette smoke extracts in vitro showed a significant impairment of their angiogenic activities (migration, adhesion, homing into ischemic tissues) that was completely rescued by probucol and antioxidant vitamins.

CONCLUSIONS

Probucol and antioxidant vitamins rescue cigarette smoke-dependent impairment of ischemia-induced neovascularization. The mechanisms involve beneficial effects on oxidative stress levels in ischemic tissues together with an improvement of EPC functional activities. Antioxidant therapy could constitute a novel therapeutic strategy to promote vessel growth and reduce tissue ischemia in atherosclerotic diseases.

Endothelial progenitor cells in vascular health: focus on lifestyle

Endothelial dysfunction, which is considered the functional equivalent of a disrupted balance between endothelial injury and repair, precedes overt atherosclerosis by many years. Although this phenomenon is part of the normal aging process, prevention of early and progressive endothelial dysfunction has become an important therapeutic target. Evidence has accumulated to show that endothelial progenitor cells (EPC), contribute substantially to preservation of a structurally and functionally intact endothelium. There has been considerable progress in our understanding of the various cell types that were in the past all covered by the term "EPC." EPC home to sites of endothelial injury and ischemia, where they proliferate, differentiate and integrate into the endothelial layer or exert a paracrine function by producing vascular growth factors. Although more emphasis has been put on the pharmacological approach of endothelial dysfunction, the effect of a healthy lifestyle, via mobilization and functional improvement of EPC, is increasingly recognized. This review will focus on successful lifestyle interventions that aim to maintain vascular health through beneficial actions on cell populations with vasculogenic potential ("EPC"). The role of physical activity and dietary recommendations, which are considered essential elements of a healthy lifestyle, will be particularly emphasized. A thorough understanding of the physiology of endothelial benefits, derived from such interventions, may help to implement these measures on top of classical drug therapy, but also provides a solid basis for primary prevention. The effects of additional elements of a comprehensive lifestyle advice, such as smoking cessation, weight and stress reduction, also comprise a modulation of EPC function and circulating numbers and are therefore included in this review as well.

Decreased in the number and function of circulation endothelial progenitor cells in patients with avascular necrosis of the femoral head

INTRODUCTION

Once non-traumatic avascular necrosis of the femoral head (ANFH) happened, vascular impairment and feeble collateral circulation are followed by poor outcomes. Circulating endothelial progenitor cells (EPCs) may substantially contribute to vascular homeostasis such as vascular repair and new blood vessel growth. We investigated whether abnormalities in EPCs levels and functions are present in ANFH patients.

METHODS

54 ANFH patients were enrolled, including steroid-induced (n=21), alcohol-induced (n=15) and idiopathic ANFH (n=18), and 30 healthy subjects as control (HC). The numbers of circulation EPCs were determined by fluorescence-activated cell-sorting (FACS) analysis. EPCs cultured from peripheral blood mononuclear cells on fibronectin to induce the expression of receptors for acetylated low-density lipoprotein and ulex-lectin. EPCs colony-forming units (CFUs) were observed from 54 patients and 30 healthy controls. Migratory capacity to chemo-attractants (vascular endothelial growth factor) cellular senescence levels and in vitro angiogenesis ability were assessed in age-matched subjects (n=10 per groups).

RESULTS

Mean numbers of circulating EPC were 1460+/-265 cells/ml in HC, 545+/-177 in ANFH, (P<0.001). Mean numbers of CFUs were 26.2+/-6.2 in HC, 19.6+/-7.7 in ANFH,(P<0.001). Although there were not significant differences in circulating EPC and CFUs among the steroid-induced, alcohol-induced or idiopathic three groups, all these risk factors contributed to the decreased circulating EPCs numbers and CFUs. In addition, EPCs from ANFH patients showed reduced migratory capacity and increased cellular senescence compared with EPCs from normal subjects, furthermore the ability of angiogenesis in vitro was also impaired.

CONCLUSION

Circulating endothelial progenitor cells (EPCs) numbers and functions are reduced in ANFH patients, suggesting that risk factors of ANFH may alter EPCs biology in angiogenesis and vascular repair.

Akt downregulation by flavin oxidase-induced ROS generation mediates dose-dependent endothelial cell damage elicited by natural antioxidants

High intake of natural antioxidants (NA) from plant-derived foods and beverages is thought to provide cardiovascular benefits. The endothelium plays a pivotal role in cardiovascular homeostasis, and for this reason, the molecular events resulting from NA actions on endothelial cells (ECs) are actively investigated. Here, we show the direct impact of two NA, coumaric acid and resveratrol, on intracellular reactive oxygen species levels, protein carbonylation, and cell physiology in human ECs. While at lower doses, both NA promoted antioxidant effects, at moderately high doses, NA elicited a dose-dependent pro-oxidant effect, which was followed by apoptosis, cell damage, and phospho-Akt downregulation. NA-induced pro-oxidant effects were counteracted by N-acetyl cysteine and diphenyleneiodonium (DPI), suggesting a role for flavin oxidases in NA-induced toxicity. DPI also prevented NA-induced phospho-Akt downregulation indicating that Akt can work downstream of flavin oxidases in mediating cellular responses to NA. Stimulation of phospho-Akt by insulin dramatically counteracted NA-induced cell death, an effect abolished by Akt inhibition further suggesting that mechanistically Akt regulates cell survival in response to NA-induced stress. Although further studies are required to better characterize the molecular mechanism of NA-induced cell toxicity, our study is the first to show in a human vascular model that moderately high doses of NA can induce cell damage mediated by flavoproteins and the Akt pathway.

Nox2-containing NADPH oxidase deficiency confers protection from hindlimb ischemia in conditions of increased oxidative stress

OBJECTIVE

Because Nox2-containing NADPH oxidase is a major source of ROS in the vasculature, we investigated its potential role for the modulation of ischemia-induced neovascularization in conditions of increased oxidative stress.

METHODS AND RESULTS

To mimic a clinical situation of increased oxidative stress, mice were exposed to cigarette smoke before and after the surgical induction of hindlimb ischemia. Nox2 expression and oxidative stress in ischemic tissues were significantly increased in wild-type mice, but not in mice deficient for the Nox2-containing NADPH oxidase (Nox2(-/-)). Nox2(-/-) mice demonstrated faster blood flow recovery, increased capillary density in ischemic muscles, and improved endothelial progenitor cell functional activities compared to Nox2(+/+) mice. In addition, Nox2 deficiency was associated with increased antioxidant and nitrite concentrations in plasma, together with a preserved expression of eNOS in ischemic tissues. In vitro, Nox2(-/-) endothelial cells exhibit resistance against superoxide induction and improved VEGF-dependent angiogenic activities compared to Nox2(+/+) endothelial cells. Importantly, the beneficial effects of Nox2 deficiency on neovascularization in vitro and in vivo were lost after treatment with the NO inhibitor L-NAME.

CONCLUSIONS

Nox2-containing NADPH oxidase deficiency protects against ischemia in conditions of increased oxidative stress. The mechanism involves improved neovascularization through a reduction of ROS formation, preserved activation of the VEGF/NO angiogenic pathway, and improved functional activities of endothelial progenitor cells.