Abstract 358: Factor Xa Deteriorates Atherosclerosis by Facilitating Inflammasome Formation via PAR-2-mediated Autophagy Suppression

Background: It is known that an endogenous blood coagulation factor Xa (FXa) plays a critical role in facilitating atherosclerosis by activating protease-activated receptor-2 (PAR-2). However, the precise mechanism how FXa-mediated PAR-2 activation promotes atherogenesis remains to be elucidated. Purpose: The aim of this study is to explore how FXa promotes atherosclerosis through PAR-2-associated signaling pathway. Methods & Results: Administration of direct FXa inhibitor rivaroxaban (Riv; 120 mg/kg/day) to the mice significantly suppressed the plasma FXa activity compared with untreated mice. Administration of Riv to ApoE knockout mice fed with high fat diet (ApoE-KO-HFD) significantly reduced atherosclerotic area in the aorta compared with those in the untreated ApoE-KO-HFD. The plaque size of ApoE-KO mice crossed with PAR-2 knockout mice fed with HFD was similar to those of Riv-treated ApoE-KO-HFD. Ultrastructural examinations of atherosclerotic lesions revealed that the number of autophagosomes in the plaque-resident macrophages of Riv-treated ApoE-KO-HFD was significantly smaller than those of the untreated ApoE-KO-HFD. Immunostaining of NLRP3 revealed that Riv attenuated the inflammasome formation in the atherosclerotic lesion in ApoE-KO-HFD. In vitro experiments demonstrated that treatment of 7-ketocholesterol (7KC) markedly enhanced autophagy activity in the murine macrophages. The addition of FXa significantly promoted mTOR (Ser 2448 ) phosphorylation and blocked autophagy activity induced by 7KC, which was reversed in the presence of Riv (1 μM). Furthermore, immunoblot analyses demonstrated that FXa administration significantly accelerated inflammasome formation induced by 7KC, which was blocked in the presence of Riv. On the other hand, treatment with FXa failed to inhibit 7KC-induced autophagy and inflammasome activation in PAR-2-KO mice-derived macrophages. Conclusion: These results suggest that FXa worsens atherogenesis through PAR-2-mediated pathway by inhibiting macrophage autophagy which, in turn, promoting inflammasome activation.

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Xenogenic macrophage immunization reduces atherosclerosis in apolipoprotein E knockout mice

AJP Cell Physiology ◽

10.1152/ajpcell.00117.2007 ◽

2007 ◽

Vol 293 (3) ◽

pp. C865-C873 ◽

Cited By ~ 3

Author(s):

Tomoya Yamashita ◽

Seinosuke Kawashima ◽

Tetsuaki Hirase ◽

Masakazu Shinohara ◽

Tomofumi Takaya ◽

...

Keyword(s):

Apolipoprotein E ◽

Critical Role ◽

Atherosclerotic Lesion ◽

Plasma Lipid ◽

Chronic Inflammatory Disease ◽

Apolipoprotein E Knockout Mice ◽

Apoe Ko Mice ◽

Apoe Ko

Atherosclerosis is a complex chronic inflammatory disease in which macrophages play a critical role, and the intervention of the inflammatory process in atherogenesis could be a therapeutic strategy. In this study, we investigated the efficacy of xenogenic macrophage immunization on the atherosclerotic lesion formation in a model of murine atherosclerosis. Apolipoprotein E knockout (apoE-KO) mice were repeatedly immunized with formaldehyde-fixed cultured human macrophages (phorbol ester-stimulated THP-1 cells), using human serum albumin as a control protein or HepG2 cells as human control cells, once a week for four consecutive weeks. The vehicle phosphate-buffered saline was injected in the nonimmunized controls. THP-1 immunization induced antibodies that are immunoreactive with mouse macrophages. Although the plasma lipid levels were unchanged by the immunization, the atherosclerotic lesion area in the aortic root was significantly reduced by >50% in 16-wk-old THP-1-immunized apoE-KO mice compared with that in control mice. THP-1 immunization reduced in vivo macrophage infiltration, reduced in vitro macrophage adhesion, and changed cytokine production by macrophages to the antiatherogenic phenotype. Xenogenic macrophage immunization protects against the development of atherosclerosis in apoE-KO mice by modulating macrophage function in which antibodies induced by the immunization are likely to be involved. This method is a novel and potentially useful cell-mediated immune therapeutic technique against atherosclerosis.

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5219A novel senolytic drug, seno-7284 ameliorates age-related cardiometabolic diseases

European Heart Journal ◽

10.1093/eurheartj/ehz746.0068 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

G Katsuumi ◽

I Katsuumi ◽

M Suda ◽

Y Yoshida ◽

Y Hayashi ◽

...

Keyword(s):

Adipose Tissue ◽

Knockout Mice ◽

Biological Effects ◽

Atherosclerotic Lesion ◽

Clinical Settings ◽

Mice Model ◽

Cardiometabolic Diseases ◽

Age Related ◽

Apoe Ko Mice ◽

Apoe Ko

Abstract Background Senescence at cellular level develops with various genotoxic stresses and it plays a pivotal role in aging and age-related disorders. Recently, it was shown that elimination of senescent cells, so called “senolysis” has potential to become a next generation therapy for age-related disorders including cardiovascular diseases, pulmonary emphysema, Alzheimer's diseases, etc. However, currently there is no senolytic agent available in clinical settings. Purpose Present study was aimed to identify a novel senolytic agent effective for cardiometabolic diseases in compounds already available in clinical settings. Here we demonstrate a compound called “seno-7284” exhibits senolytic effect in murine models of type 2 diabetes, atherosclerosis and progeroid. Methods We generated 1) diet-induced obase and diabetic model by imposing a high fat diet for two months, 2) atherosclerosis mice model by imposing western diet to ApoE homozygous knockout mice (ApoE-KO mice) for three months, and 3) Zmpste24 homozygous knockout mice (Zmpste24-KO mice) as a progeroid mice model. We administrated seno-7284 by mixing it into the diet (0.03% w/w). In one, two or four weeks after the administration of seno-7284 to each mice model, we collected tissue samples for further analyses. Results Seno-7284 reduced the accumulation of senescent cells in visceral adipose tissue of dietary obese mice as senescence-associated beta-galactosidase (SA-beta-gal) staining exhibits (Figure a). This effect was associated with the suppression in systemic glucose intolerance (Figure b), and adipose tissue inflammation in four weeks after the administration of seno-7284. Administrating seno-7284 for two weeks also reduced accumulation of senescent cells in atherosclerotic lesion in aorta of ApoE-KO mice (Figure c), and inhibited the progression of atherosclerosis (Figure d). Surprisingly, this drug significantly improved the lifespan of Zmpste24-KO mice by administering it from 12 weeks old. Further analysis including RNA-seq or metabolomic analysis suggested that seno-7284 stimulates endogenous senolytic function of NK cells and CD8+ T cells. Conclusion Our results indicate that seno-7284 mediates its biological effects by inducing senolysis in some murine aging models. Seno-7284 would become a promising therapeutic agent for age-related cardiometabolic diseases.

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Abstract 458: Fcgamma Receptor IV Expressed on Inflammatory Cells Drive Diet-induced Atherosclerosis in Hyperlipidemic Mouse Model

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.458 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Branimir Popovic ◽

Doug Feck ◽

Shanmugam Nagarajan

Keyword(s):

T Cells ◽

Mouse Model ◽

Knockout Mice ◽

Inflammatory Responses ◽

Inflammasome Activation ◽

Double Knockout ◽

Arterial Lesions ◽

Apoe Ko Mice ◽

Progression Of Atherosclerosis ◽

Apoe Ko

Objective: Functionally, Fcgamma receptors (FcgRs) can be classified as activating (FcgRI, III, and IV) and inhibitory (FcgRII) receptors. We have reported that combined deficiency of all three activating FcgRs in apoE knockout mice decreased atherosclerosis. In this report, we investigated the independent role of FcgRI and FcgRIV in the progression of atherosclerosis. We investigated the hypothesis that the deficiency of FcgRIV, one of the activating FcgRs, inhibits atherosclerosis in a hypercholesterolemic mouse model. We tested the hypothesis that FcgRI and FcgRIV exacerbate atherosclerosis using apoE-FcgRI dKO and apoE-FcgRIV deficient mice. Approach and Results: ApoE-FcgRI and apoE-FcgRIV double knockout mice (dKO) congenic to the C57BL/6 were generated and atherosclerotic lesions were assessed. Our results show that arterial lesions were not different between apoE-FcgRI dKO and apoE knockout (apoE KO) mice. Interestingly, arterial lesions were significantly decreased in a regular chow or a high-fat diet fed apoE-FcgRIV dKO male and female mice, relative to apoE KO mice. Bone marrow chimeras were used to address the relative contribution of FcgRIV expressed on hematopoietic cells including macrophages and dendritic cell. ApoE KO mice transplanted with apoE-FcgRIV dKO marrow showed significantly reduced arterial lesions relative to recipient mice transplanted with apoE KO marrow. Next, we investigated whether pro-inflammatory response contributed to the pro-atherogenic effect of FcgRIV. Activated CD4+ T cells of apoE-FcgRIV dKO mice showed increased secretion of IL-10, whereas IFN-gamma and IL-17 by T cells were decreased. Interestingly, dendritic cells at the lesion-prone vascular site from apoE-FcgRIV dKO mice induced increased IL-10 secretion by LDL-specific T cells. Moreover, FcgRIV KO and apoE-FcgRIV dKO macrophages showed decreased inflammasome activation as evidenced by decreased IL-1 beta response. Conclusions: Our findings demonstrate that the pro-inflammatory responses initiated by FcgRIV, one of the activating FcgRs, contribute to the progression of atherosclerosis.

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Berberine attenuates choline-induced atherosclerosis by inhibiting trimethylamine and trimethylamine-N-oxide production via manipulating the gut microbiome

npj Biofilms and Microbiomes ◽

10.1038/s41522-021-00205-8 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Xingxing Li ◽

Chunyan Su ◽

Zhibo Jiang ◽

Yuxin Yang ◽

Yue Zhang ◽

...

Keyword(s):

Gut Microbiota ◽

Atherosclerotic Lesion ◽

Chow Diet ◽

Dose Administration ◽

Human Volunteers ◽

Apoe Ko Mice ◽

Gut Microbiota Composition ◽

Apoe Ko

AbstractTrimethylamine-N-oxide (TMAO), a derivative from the gut microbiota metabolite trimethylamine (TMA), has been identified to be an independent risk factor for promoting atherosclerosis. Evidences suggest that berberine (BBR) could be used to treat obesity, diabetes and atherosclerosis, however, its mechanism is not clear mainly because of its poor oral bioavailability. Here, we show that BBR attenuated TMA/TMAO production in the C57BL/6J and ApoE KO mice fed with choline-supplemented chow diet, and mitigated atherosclerotic lesion areas in ApoE KO mice. Inhibition of TMA/TMAO production by BBR-modulated gut microbiota was proved by a single-dose administration of d9-choline in vivo. Metagenomic analysis of cecal contents demonstrated that BBR altered gut microbiota composition, microbiome functionality, and cutC/cntA gene abundance. Furthermore, BBR was shown to inhibit choline-to-TMA conversion in TMA-producing bacteria in vitro and in gut microbial consortium from fecal samples of choline-fed mice and human volunteers, and the result was confirmed by transplantation of TMA-producing bacteria in mice. These results offer new insights into the mechanisms responsible for the anti-atherosclerosis effects of BBR, which inhibits commensal microbial TMA production via gut microbiota remodeling.

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Ancylostoma caninum Anticoagulant Peptide Blocks Metastasis In Vivo and Inhibits Factor Xa Binding to Melanoma Cells In Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0037-1615117 ◽

1998 ◽

Vol 79 (05) ◽

pp. 1041-1047 ◽

Cited By ~ 20

Author(s):

Kathleen M. Donnelly ◽

Michael E. Bromberg ◽

Aaron Milstone ◽

Jennifer Madison McNiff ◽

Gordon Terwilliger ◽

...

Keyword(s):

Active Site ◽

Thrombin Generation ◽

Factor Xa ◽

Coagulation Factor ◽

Melanoma Cells ◽

Factor V ◽

Ancylostoma Caninum ◽

Metastatic Activity

SummaryWe evaluated the in vivo anti-metastatic activity of recombinant Ancylostoma caninum Anticoagulant Peptide (rAcAP), a potent (Ki = 265 pM) and specific active site inhibitor of human coagulation factor Xa originally isolated from bloodfeeding hookworms. Subcutaneous injection of SCID mice with rAcAP (0.01-0.2 mg/mouse) prior to tail vein injection of LOX human melanoma cells resulted in a dose dependent reduction in pulmonary metastases. In order to elucidate potential mechanisms of rAcAP’s anti-metastatic activity, experiments were carried out to identify specific interactions between factor Xa and LOX. Binding of biotinylated factor Xa to LOX monolayers was both specific and saturable (Kd = 15 nM). Competition experiments using antibodies to previously identified factor Xa binding proteins, including factor V/Va, effector cell protease receptor-1, and tissue factor pathway inhibitor failed to implicate any of these molecules as significant binding sites for Factor Xa. Functional prothrombinase activity was also supported by LOX, with a half maximal rate of thrombin generation detected at a factor Xa concentration of 2.4 nM. Additional competition experiments using an excess of either rAcAP or active site blocked factor Xa (EGR-Xa) revealed that most of the total factor Xa binding to LOX is mediated via interaction with the enzyme’s active site, predicting that the vast majority of cell-associated factor Xa does not participate directly in thrombin generation. In addition to establishing two distinct mechanisms of factor Xa binding to melanoma, these data raise the possibility that rAcAP’s antimetastatic effect in vivo might involve novel non-coagulant pathways, perhaps via inhibition of active-site mediated interactions between factor Xa and tumor cells.

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Inhibition of human coagulation factor VIII by monoclonal antibodies. Mapping of functional epitopes with the use of recombinant factor VIII fragments

Biochemical Journal ◽

10.1042/bj2630187 ◽

1989 ◽

Vol 263 (1) ◽

pp. 187-194 ◽

Cited By ~ 41

Author(s):

A Leyte ◽

K Mertens ◽

B Distel ◽

R F Evers ◽

M J M De Keyzer-Nellen ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Factor Viii ◽

Factor Xa ◽

Coagulation Factor ◽

Procoagulant Activity ◽

Coagulation Factor Viii ◽

Coagulation Cascade ◽

Restriction Enzyme Digestion ◽

Proteolytic Activation

The epitopes of four monoclonal antibodies against coagulation Factor VIII were mapped with the use of recombinant DNA techniques. Full-length Factor VIII cDNA and parts thereof were inserted into the vector pSP64, permitting transcription in vitro with the use of a promoter specific for SP6 RNA polymerase. Factor VIII DNA inserts were truncated from their 3′-ends by selective restriction-enzyme digestion and used as templates for ‘run-off’ mRNA synthesis. Translation in vitro with rabbit reticulocyte lysate provided defined radiolabelled Factor VIII fragments for immunoprecipitation studies. Two antibodies are shown to be directed against epitopes on the 90 kDa chain of Factor VIII, between residues 712 and 741. The 80 kDa chain appeared to contain the epitopes of the other two antibodies, within the sequences 1649-1778 and 1779-1840 respectively. The effect of antibody binding to these sequences was evaluated at two distinct levels within the coagulation cascade. Both Factor VIII procoagulant activity and Factor VIII cofactor function in Factor Xa generation were neutralized upon binding to the region 1779-1840. The antibodies recognizing the region 713-740 or 1649-1778, though interfering with Factor VIII procoagulant activity, did not inhibit in Factor Xa generation. These findings demonstrate that antibodies that virtually inhibit Factor VIII in coagulation in vitro are not necessarily directed against epitopes involved in Factor VIII cofactor function. Inhibition of procoagulant activity rather than of cofactor function itself may be explained by interference in proteolytic activation of Factor VIII. This hypothesis is in agreement with the localization of the epitopes in the proximity of thrombin-cleavage or Factor Xa-cleavage sites.

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Heparin is more effective than apixaban in inhibiting in vitro contact activated coagulation

European Heart Journal ◽

10.1093/ehjci/ehaa946.3776 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

M.M Engelen ◽

C Van Laer ◽

M Jacquemin ◽

C Vandenbriele ◽

K Peerlinck ◽

...

Keyword(s):

Thrombin Generation ◽

Heart Valves ◽

Thrombus Formation ◽

Oral Anticoagulants ◽

Direct Oral Anticoagulants ◽

Factor Xa ◽

Coagulation Factor ◽

Mechanical Heart Valves ◽

Contact Activation

Abstract Introduction Contact of blood with artificial surfaces such as mechanical support devices, catheters, and mechanical heart valves activates the contact activation (CA) pathway of coagulation. Furthermore, recent animal data and clinical studies suggest a more important contribution of CA in pathological thrombus formation in other cardiovascular diseases. Direct oral anticoagulants (DOACs) are recommended as first-line treatment in most patients who require long-term anticoagulation. However, because DOACs directly inhibit a single downstream coagulation factor (thrombin (fXIIa) or factor Xa (fXa)), it has been suggested that their efficacy could be reduced in the presence of strong activation of the CA pathway as compared to anticoagulants that target multiple, more upstream located coagulation factors. Purpose To compare the efficacy of a DOAC (apixaban) and heparin to suppress thrombin generation in the presence of strong CA pathway activation. Methods Pooled platelet-poor plasma was spiked with either apixaban (dissolved in DMSO and PBS) or unfractionated heparin to achieve therapeutic plasma levels. SynthASil, a commercially available mixture of phospholipids and silica, was used to stimulate the CA pathway in two different dilutions (1–80 and 5–80). Downstream coagulation was accessed by Thrombin Generation Test using Thrombinoscope by Stago and associated Thrombin Calibrator (activity 640 nM). The endogenous thrombin potential (area under the thrombin generation curve; ETP), peak thrombin generation (PTG), time to peak (ttPeak) and time to start (ttStart) were accessed. Results With decreasing concentrations of apixaban, stimulation with the lower dose SynthASil reveals an increasing ETP and PTG. As expected, ttPeak and ttStart decreased. Even supratherapeutic levels of apixaban (i.e. 1120 ng/mL) could not inhibit thrombin from being generated, in striking contrast with UFH where no thrombin was formed. Using a five times higher dose of SynthASil showed comparable ETP for all concentrations of apixaban, allocated around the control value. PTG, however, slightly increased with decreasing concentrations of apixaban. ttPeak and ttStart slightly decreased. Except for the subtherapeutic UFH concentration of 0,114 IU/mL, no thrombin was generated with UFH. Conclusion UFH is more effective in inhibiting downstream thrombin generation compared to apixaban as a response to activation of the CA pathway in vitro. These findings could help explain why direct inhibitors were not able to show non-inferiority in patients with mechanical heart valves and support the development of specific CA pathway inhibitors for patients with conditions that activate the CA pathway. Thrombin generation curves Funding Acknowledgement Type of funding source: None

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Rabeprazole inhibits inflammatory reaction by inhibition of cell pyroptosis in gastric epithelial cells

BMC Pharmacology and Toxicology ◽

10.1186/s40360-021-00509-7 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Jing Xie ◽

Long Fan ◽

Liya Xiong ◽

Peiyu Chen ◽

Hongli Wang ◽

...

Keyword(s):

Epithelial Cells ◽

Clinical Sample ◽

Critical Role ◽

Enzyme Linked Immunosorbent Assay ◽

Inflammasome Activation ◽

Peptic Ulcers ◽

Gastric Epithelial Cells ◽

Caspase 1 ◽

H Pylori

Abstract Background Helicobacter pylori (H. pylori) is a common pathogen in development of peptic ulcers with pyroptosis. Rabeprazole, a critical component of standard triple therapy, has been widely used as the first-line regimen for H. pylori infectious treatment. The aim of this study to explore the function of Rabeprazole on cell pyroptosis in vitro. Methods The clinical sample from patients diagnosed with or without H. pylori-infection were collected to analyze by Immunohistochemistry (IHC). Real-time quantitative PCR (qPCR), western blot (WB) and enzyme linked immunosorbent assay (Elisa) were performed to analyze the effect of Rabeprazole on cell pyroptosis, including LDH, IL-1β and IL-18. Results In this study, we showed that Rabeprazole regulated a phenomenon of cell pyroptosis as confirmed by lactate dehydrogenase (LDH) assay. Further results showed that Rabeprazole inhibited cell pyroptosis in gastric epithelial cells by alleviating GSDMD-executed pyroptosis, leading to decrease IL-1β and IL-18 mature and secretion, which is attributed to NLRP3 inflammasome activation inhibition. Further analysis showed that ASC, NLRP3 and Caspase-1, was significantly repressed in response to Rabeprazole stimulation, resulting in decreasing cleaved-caspase-1 expression. Most important, NLRP3 and GSDMD is significantly increased in gastric tissue of patients with H. pylori infection. Conclusion These findings revealed a critical role of Rabeprazole in cell pyroptosis in patients with H. pylori infection, suggesting that targeting cell pyroptosis is an alternative strategy in improving H. pylori treatment.

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Abstract 1444: Overexpression Of Endothelial Nitric Oxide Synthase Restores Post-natal Neovascularization In Atherosclerosis.

Circulation ◽

10.1161/circ.116.suppl_16.ii_297-b ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Barend Mees ◽

Ludovic Waeckel ◽

Dong You ◽

Dennie Tempel ◽

Maria Godinho ◽

...

Keyword(s):

Bone Marrow ◽

Hind Limb ◽

Fold Increase ◽

Tissue Perfusion ◽

Vessel Density ◽

Plaque Size ◽

Angiogenic Potential ◽

Apoe Ko Mice ◽

Apoe Ko

Alteration in post-ischemic neovascularization is a common complication of atherosclerotic disease. This results, at least in part, from abrogation of bone-marrow mononuclear cells (BM-MNC) pro-angiogenic potential. Overexpression of eNOS has been shown to promote vessel growth in the setting of ischemia. We hypothesized that eNOS overexpression could restore impaired neovascularization in atherosclerotic (ApoE KO) mice. Hind limb ischemia was induced in mice by right femoral artery ligation. After two weeks we evaluated tissue perfusion of the foot by Laser Doppler, vessel density in the hind limb by micro-angiography and histology, and atherosclerotic plaque size. In vitro BM-MNC cell culture assays were performed. Tissue perfusion and vessel density were 1.5-fold increased in transgenic mice overexpressing eNOS (eNOStg) as compared to wild type (WT) (P<0.001, n=10). Transplantation of 1x106 WT- or eNOStg BM-MNC in WT recipients caused a 1.5-fold increase in tissue perfusion and vessel density compared to injection of PBS (P<0.001, n=10). Next, we used ApoE KO mice and crossbreeds of eNOStg and ApoE KO mice (eNOStg*ApoE KO). Tissue perfusion and vessel density were 1.8-fold increased in eNOStg*ApoE KO mice as compared to ApoE KO mice (P<0.001, n=10). Transplantation of both WT- or eNOStg*ApoE KO BM-MNC in ApoE KO recipients caused a 1.6- to 2-fold increase in tissue perfusion and vessel density compared to PBS (P<0.01, n=10), while transplantation of ApoE KO BM-MNC had no positive effect on neovascularization. Moreover, transplantation of WT BM-MNC significantly increased plaque size, while eNOStg*ApoE KO BM-MNC had no effect on plaque size. eNOS overexpression did not affect BM-MNC apoptosis and secretion of growth factors but increased their ability to differentiate in vitro into EPC. Conclusion: eNOS overexpression in the endothelium improves post-ischemic neovascularization in both physiological as atherosclerotic settings. Furthermore, eNOS overexpression in the bone marrow restores the impaired pro-angiogenic potential of atherosclerotic BM-MNC without adverse effects on plaque size. Therefore, overexpression of eNOS could play a vital part in the development of therapeutic angiogenesis for atherosclerotic disease.

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