Apelin and vascular endothelial growth factor are associated with mobilization of endothelial progenitor cells after acute myocardial infarction

This study was designed to determine the levels of early endothelial progenitor cells （EPCs）, apelin, vascu- lar endothelial growth factor （VEGF） and stromal cell-derived growth factor-1 （SDF-1） after acute myocardial infarction （AMI）, and to investigate the relationships between these cytokines and early EPCs. Early EPCs, de- fined as CD133＋, KDR＋, and CD34~ cells, were quantified by flow cytometry. The levels of early EPCs and those cytokines in AMI patients were significantly different from those with coronary artery disease or controls （P 〈 0.05）. Plasma apelin levels were inversely correlated with Gensini score and early EPCs （both P 〈 0.01）. Early EPCs, VEGF and SDF-1 showed different patterns of changes in AMI patients during the first 24 h. The trend in the change of early EPCs was proportionally correlated with that of VEGF （P 〈 0.05）. AMI patients exhibited in- creased early EPCs with remarkably decreased apelin levels and enhanced VEGF levels.

Transplantation of vascular endothelial growth factor-modified neural stem/progenitor cells promotes the recovery of neurological function following hypoxic-ischemic brain damage

Neural stem/progenitor cell （NSC） transplantation has been shown to effectively improve neurological function in rats with hypoxic-isch- emic brain damage. Vascular endothelial growth factor （VEGF） is a signaling protein that stimulates angiogenesis and improves neural regeneration. We hypothesized that transplantation of VEGF-transfected NSCs would alleviate hypoxic-ischemic brain damage in neo- natal rats. We produced and transfected a recombinant lentiviral vector containing the VEGF165gene into cultured NSCs. The transfected NSCs were transplanted into the left sensorimotor cortex of rats 3 days after hypoxic-ischemic brain damage. Compared with the NSCs group, VEGF mRNA and protein expression levels were increased in the transgene NSCs group, and learning and memory abilities were significantly improved at 30 days. Furthermore, histopathological changes were alleviated in these animals. Our findings indicate that transplantation of VEGF-transfected NSCs may facilitate the recovery of neurological function, and that its therapeutic effectiveness is better than that of unmodified NSCs.

Correlation between Increased Circulating Endothelial Progenitor Cells and Stage of non-Hodgkin Lymphoma

This study aims to examine the levels of circulating endothelial progenitor cells （cEPCs） in the peripheral blood of patients with non-Hodgkin lymphoma （NHL） and their correlation with the tumor stage. Forty-one patients with biopsy-proven NHL and 16 healthy individuals were recruited. Pe- ripheral blood mononuclear cells （PBMCs） were isolated by density gradient centrifugation, and cEPCs were characterized by triple staining using antibodies against CD133, CD34 and vascular endothelial growth factor receptor-2 （VEGFR-2, CD309） and quantified by flow cytometry. In NHL patients, the number of cEPCs was significantly greater than in control group （P=-0.000）. The cEPCs counts in patients with NHL of stage III-1V were significantly greater than in stage I -II （P=-0.010）. FACS analysis revealed that the number of cEPCs in NHL patients had no correlation with the gender （P=0.401） or the pathological category （P=0.852）. It was suggested that the over-expression of cEPCs in NHL patients may serve as a novel biomarker for disease progression in NHL.

Erythropoietin Receptor Positive Circulating Progenitor Cells and Endothelial Progenitor Cells in Patients with Different Stages of Diabetic Retinopathy

Objective To investigate the possible involvement of erythropoietin （EPO）/erythropoietin receptor （EPOR） system in neovascularization and vascular regeneration in diabetic retinopathy （DR）. Methods EPOR positive circulating progenitor cells （CPCs： CD34^＋） and endothelial progenitor cells （EPCs： CD34^＋KDR^＋） were assessed by flow cytometry in type 2 diabetic patients with different stages of DR. The cohort consisted of age- and sex-matched control patients without diabetes （n=7）, non-prolif- erative DR （NPDR, n=7）, proliferative DR （PDR, n=8）, and PDR complicated with diabetic nephropathy （PDR-DN, n=7）. Results The numbers of EPOR^＋ CPCs and EPOR^＋ EPCs were reduced remarkably in NPDR corn pared with the control group （both P（0.01）, whereas rebounded in PDR and PDR-DN groups in varying degrees. Similar changes were observed in respect of the proportion of EPOR^＋ CPCs in CPCs （NPDR vs. control, P（0.01） and that of EPOR^＋ EPCs in EPCs （NPDR vs. control, P〈0.05）. Conclusion Exogenous EPO, mediated via the EPO/EPOR system of EPCs, may alleviate the impaired vascular regeneration in NPDR, whereas it might aggravate retinal neovascularization in PDR due to a rebound of EPOR^＋ EPCs associated with ischemia.

Effect of Buyang Huanwu Decoction on the proliferation,migration and adhesion of endothelial progenitor cells in rats with acute myocardial infarction

Objective:To investigate the intervention effect of Buyang Huanwu Decoction on endothelial progenitor cell function(EPCs),and to explore the therapeutic mechanism of Buyang Huanwu Decoction.Methods:This research take 54 rats were divided into blank group,the control group,model group,Chinese medicine,western medicine group and combine traditional Chinese and western medicine group,tonifying Yang also five decoction and atorvastatin calcium for acute myocardial infarction(AMI)rats group intervention,by using the method of density gradient centrifugation separation training each rat endothelial progenitor cells,using tetramethyl azo salt trace enzyme reaction colorimetry,used in the determination of adhesion ability and improved Boyden chamber,the method of analysis and comparison between groups of endothelial progenitor cells proliferation,adhesion and migration.Results:In 7 days,14 days and 4 weeks,acute myocardial infarction model of rat peripheral blood EPCs count,proliferation,migration and adhesion ability were compared with control group were significantly decline,tonifying Yang also five decoction group,western medicine control group and combine traditional Chinese and western medicine group of peripheral blood EPCs count,proliferation,migration and adhesion ability compared with model group were significantly increased(P<0.05),and combine traditional Chinese and western medicine group is the traditional Chinese medicine and western medicine group on the improvement of the function of EPCs effect more significantly(P<0.05).Conclusion:Statins combined with Buyang Huanwu Decoction can better improve the endothelial function of AMI rats than traditional Chinese medicine or western medicine.Further clinical studies on statins may better improve the endothelial function of AMI patients,and provide a new research entry point for improving the long-term prognosis of AMI patients.

Transfusion of CXCR4-priming endothelial progenitor cells reduces cerebral ischemic damage and promotes angiogenesis and neurogenesis in db/db diabetic mice

Previous studies suggest that reduction and dysfunction of circulating endothelial progenitor cells(EPCs),and dysregulation in stromal cell derived factor-1/CXC-chemokine receptor 4(SDF-1/ CXCR4) axis in diabetes could be therapeutic targets for diabetic ischemic stroke.This study investigated the efficacy of CXCR4-priming EPCs on cerebral repair following ischemic stroke in db/db diabetic mice.Bone marrow derived EPCs from db/+ control mice were transfected with adenovirus(1×10~7 IU) carrying CXCR4(Ad-CXCR4-EPCs)or null(Ad- null-EPCs).The db/db mice were divided into three groups for EPCs injection(2×10~5 cells/100μl): Ad-CXCR4-EPCs,Ad-null-EPCs or saline(vehicle), via tail vein 2 hrs after middle cerebral artery occlusion (MCAO) surgery.Cerebral blood flow(CBF) was measured with laser Doppler flowmeter.Mice were sacrificed at 2 or 7 days thereafter.Level of circulating EPCs was measured by flow cytometry. Ischemic damage,cerebral microvascular density (MVD),angiogenesis and neurogenesis were determined by histological staining with Fluoro-J,CD31, CD31 +BrdU,NeuN +BrdU,GFAP+BrdU,respectively. Results(table) showed:1) Levels of CXCR4 expression were reduced in the brain and EPCs of db/db mice as measured by real-time RT-PCR and western blot analyses(data not shown);2) The level of circulating EPCs was more in the mice treated with Ad-CXCR4-EPCs;3)EPC transfusion improved CBF,increased MVD,angiogenesis and neurogenesis in peri-infarct area,and decreased ischemic damage.The efficacies were better in Ad-CXCR4 -EPCs group.Data suggest that transfusion of Ad-CXCR4-EPCs could be a therapeutic avenue for ischemia stroke in diabetes.

Transplantation of endothelial progenitor cells transfected with VEGF165 to restore erectile function in diabetic rats

The present study investigated the effect of transplanting endothelial progenitor cells （EPCs） transfected with the vascular endothelial growth factor gene （VEGF165） into the corpora cavernosa of rats with diabetic erectile dysfunction （ED）. A rat model of diabetic ED was constructed via intraperitoneal injection of streptozotocin. After streptozotocin treatment, pre-treated EPCs from each of three groups of rats were transplanted into their corpora cavernosa. Our results, following intracavernosal pressure （ICP） monitoring, showed that ICP increased significantly among rats in the trial group when compared to the results from rats in the blank-plasmid and control groups during basal conditions and electrical stimulation （P〈O.01 for both comparisons）. Histological examination revealed extensive neovascularisation in the corpora cavernosa of rats in the trial group. Fluorescence microscopy indicated that many of the transplanted EPCs in the trial group survived, differentiated into endothelial cells and integrated into the sites of neovascularisation. Based on the results of this study, we conclude that transplantation of VEGF165-transfected EPCs into the corpora cavernosa of rats with diabetic ED restores erectile function.

Growth factor- and cytokine-stimulated endothelial progenitor cells in post-ischemic cerebral neovascularization

Endothelial progenitor cells are resident in the bone marrow blood sinusoids and circulate in the peripheral circulation. They mobilize from the bone marrow after vascular injury and home to the site of injury where they differentiate into endothelial cells. Activation and mobilization of endothelial progenitor cells from the bone marrow is induced via the production and release of endothelial progenitor cell-activating factors and includes specific growth factors and cytokines in response to peripheral tissue hypoxia such as after acute ischemic stroke or trauma. Endotheli- al progenitor cells migrate and home to specific sites following ischemic stroke via growth factor/ cytokine gradients. Some growth factors are less stable under acidic conditions of tissue isch- emia, and synthetic analogues that are stable at low pH may provide a more effective therapeutic approach for inducing endothelial progenitor cell mobilization and promoting cerebral neovascularization following ischemic stroke.

Angiotensin Ⅱ promotes NO production, inhibits apoptosis and enhances adhesion potential of bone marrow-derived endothelial progenitor cells

Endothelial progenitor cells （EPCs） participate in the processes of postnatal neovascularization and re-endothelialization in response to tissue ischemia and endothelial injury. The level of EPCs present has been found to be directly associated with the outcome of cardiovascular diseases, and could be regulated by stimulatory or inhibitory factors. Given the close relationship between angiotensin Ⅱ （AngⅡ） and the cardiovascular＇ system, we investigated the effect of AngⅡ on the activities of bone marrow （BM）-derived EPCs. Cells were isolated from BM of rats by density gradient centrifugation. Administration of AngⅡ significantly promoted nitric oxide （NO） release, inhibited EPC apoptosis and enhanced EPC adhesion potential. All of these AngⅡ-mediated effects on EPCs were attenuated by pretreatment with valsartan or L-NAME. Moreover, both LY294002 and wortmannin abolished the anti-apoptotic effect of AngⅡ. Western blot analyses indicated that endothelial NO synthase （eNOS） protein and phosphorylated Akt increased with the treatment of AngⅡ in EPCs. Thus, AngⅡ improved several activities of EPCs through AngⅡ type 1 receptor （AT1R）, which may represent a possible mechanism linking AnglI and ATIR with angiogenesis. Additionally, AngⅡ-induced NO synthesis through eNOS in EPCs regulates apoptosis and adhesion, and the PI3-kinase/Akt pathway has an essential role in AngⅡ-induced antiapoptosis signaling.

Mobilisation of endothelial progenitor cells： one of the possible mechanisms involved in the chronic administration of melatonin preventing erectile dysfunction in diabetic rats

Diabetes-induced oxidative stress plays a critical role in the mobilisation of endothelial progenitor cells （EPCs） from the bone marrow to the circulation. This study was designed to explore the effects of chronic melatonin administration on the promotion of the mobilisation of EPCs and on the preservation of erectile function in type I diabetic rats. Melatonin was administered to streptozotocin-induced type I diabetic rats. EPCs levels were determined using flow cytometry. Oxidative stress in the bone marrow was indicated by the levels of superoxide dismutase and malondialdehyde. Erectile function was evaluated by measuring the intracavernous pressure during an electrostimulation of the cavernous nerve. The density of the endothelium and the proportions of smooth muscle and collagen in the corpus cavernosum were determined by immunohistochemistry. The administration of melatonin increased the superoxide dismutase level and decreased the malondialdehyde level in the bone marrow. This effect was accompanied by an increased level of circulating EPCs in the diabetic rats. The intracavernous pressure to mean arterial pressure ratio of the rats in the treatment group was significantly greater, compared with diabetic control rats. The histological analysis demonstrated an increase in the endothelial density of the corpus cavernosum after the administration of melatonin. However, melatonin treatment did not change the proportions of smooth muscle and collagen in the corpus cavernosum of diabetic rats. Chronic administration of melatonin has a beneficial effect on preventing erectile dysfunction （ED） in type I diabetic rats. Promoting the mobilisation of EPCs is one of the possible mechanisms involved in the improvement of ED.

Adult endothelial progenitor cells from human peripheral blood maintain monocyte/macrophage function throughout in vitro culture

Mononuclear cells （MNCs） isolated from peripheral blood by density gradient centrifugation were plated on human fibronectin-coated culture plates and cultured in EGM-2 medium. Attached spindle-shaped cells, reported as endothelial progenitor cells （EPCs） by some investigators, had elongated from adherent round cells, but had not proliferated from a small number of cells as supposed previously. The growth curve of the primary EPCs showed that the cells had little proliferative capacity. Flow cytometry analysis showed that the cells could express some of the endothelial lineage markers, while they could also express CD 14, which is considered a marker of monocyte/macrophage lineages throughout culture. In endothelial function assays, the cells demonstrated a lower level of expression of eNOS than mature endothelial cells in the reverse transcription-polymerase chain reaction and did not show an ability to develop tube-like structures in angiogenesis assay in vitro. In this study, we identified the monocytoid function of EPCs by the combined Dillabeled acetylated low-density lipoprotein （Dil-Ac-LDL） and Indian ink uptake tests. All the cells were double positive for Dil- Ac-LDL and Indian ink uptake at days 4, 14 and 28 of culture, which means the EPCs maintained monocytoid function throughout the culture. Therefore, although adult EPCs from peripheral MNCs have some endothelial lineage properties, they maintain typical monocytic function and have little proliferative capacity.

Changes in Number and Biological Function of Endothelial Progenitor Cells in Hypertension Disorder Complicating Pregnancy

To examine the changes in number and function of endothelial progenitor cells （EPCs） from peripheral blood （PB） in hypertension disorder complicating pregnancy （HDCP）, 20 women with HDCP and 20 normal pregnant women at the third trimester were studied. Mononuclear cells （MNCs） from PB were isolated by Ficoll density gradient centrifugation. EPCs were identified by positive expression of both CD34 and CD133 under fluorescence microscope and positive expression of factor Ⅷ as shown by immunocytochemistry. The number of EPCs was flow-cytometrically determined. Proliferation and migration of EPCs were measured by MTT assay and modified Boyden chamber assay, respectively. The adhesion activity of EPCs was detected by counting the number of the adherent cells. The results showed that, compared with normal pregnant women, the number of EPCs was significantly reduced in HDCP （4.29%±1.21% vs 15.32%±2.00%, P〈0.01）, the functional activity of EPCs in HDCP, such as proliferation （13.45%±1.68% vs 18.45%±1.67%）, migration （37.25±7.28 cells/field vs 67.10±9.55 cells/field） and adhesion activity （20.65±5.19 cells/field vs 34.40±6.72 cells/filed） was impaired （P〈0.01）. It is concluded that the number and function of EPCs are significantly decreased in HDCP.

The secretome of endothelial progenitor cells: a potential therapeutic strategy for ischemic stroke

Ischemic stroke continues to be a leading cause of mortality and morbidity in the world. Despite recent advances in the field of stroke medicine, thrombolysis with recombinant tissue plasminogen activator remains as the only pharmacological therapy for stroke patients. However, due to short therapeutic window(4.5 hours of stroke onset) and increased risk of hemorrhage beyond this point, each year globally less than 1% of stroke patients receive this therapy which necessitate the discovery of safe and efficacious therapeutics that can be used beyond the acute phase of stroke. Accumulating evidence indicates that endothelial progenitor cells(EPCs), equipped with an inherent capacity to migrate, proliferate and differentiate, may be one such therapeutics. However, the limited availability of EPCs in peripheral blood and early senescence of few isolated cells in culture conditions adversely affect their application as effective therapeutics. Given that much of the EPC-mediated reparative effects on neurovasculature is realized by a wide range of biologically active substances released by these cells, it is possible that EPC-secretome may serve as an important therapeutic after an ischemic stroke. In light of this assumption, this review paper firstly discusses the main constituents of EPC-secretome that may exert the beneficial effects of EPCs on neurovasculature, and then reviews the currently scant literature that focuses on its therapeutic capacity.

Sleep-disordered breathing is associated with depletion of circulating endothelial progenitor cells and elevation in pulmonary arterial pressure in patients with decompensated systolic heart failure

Background Sleep-disordered breathing （SDB） is known to occur frequently in and may predict worsening progression of patients with congestive heart failure （CHF）. SDB is also known to play an important role in the development of idiopathic pulmonary arterial hyper- tension （PAH） via inducing endothelial dysfunction and vascular remodeling, a pathological process that can be significantly influenced by factors such as osteoprotegerin （OPG） and endothelial progenitor cells （EPCs）. The objective of this study is to determine if CHF with SDB is associated with changes in OPG, EPCs, and PAIl. Methods EPCs were isolated, cultured, and quantified from CHF patients with SDB （n = 52）, or without SDB （n - 68）. OPG and N-terminal pro-brain natriuretic peptide （NT-proBNP） from each group was analyzed and cor- related with EPCs and the mean pulmonary artery pressure （mPAP） measured by right heart catheterization. Results A significant decrease in circulating EPCs （29.30 ± 9.01 vs. 45.17 ± 10.51 EPCs/x 200 field; P 〈 0.05） was found in CHF patients with SDB compared to those without SDB. Both OPG （789.83 ±89.38 vs. 551.29 ± 42.12 pg/mL; P 〈 0.05） and NT-proBNP （5946.50 ± 1434.50 vs. 3028.60 ± 811.90 ng/mL; P 〈 0.05） were also significantly elevated in SDB CHF patients who also had significantly elevated mPAP （50.2 ± 9.5 vs. 36.4 ± 4.1 mm Hg; P 〈 0.05）. EPC numbers correlated inversely with the episodes of apnea and hypopnea per hour （RDI, r = -0.45, P = 0.037） and blood level of OPG （r =-0.53, P = 0.011）. Although NT-proBNP was also increased significantly in patients with SDB, it had no correlation with either EPCs or RD1. Conclusions SDBdue to hypoxemia from decompensated CHF is associated with （1） OPG elevation, （2） EPC depletion, and （3） mPAP elevation. The inverse relationship of circulating OPG with EPCs suggests a likely mechanism for hypoxemia and OPG in the development of pulmonary vascular dysfunction via depleting EPCs, thus worsening prognosis of CHF.

Effect of endothelial progenitor cells derived from human umbilical cord blood on oxygen-induced retinopathy in mice by intravitreal transplantation

AIM： To investigate the effect of endothelial progenitor cells（EPCs） labeled by carboxy fluorescein diacetate succinimidyl ester（CFSE） on murine oxygen-induced retinopathy（OIR） by intravitreal transplantation.METHODS： After isolated from human umbilical cord blood mononuclear cells, EPCs were cultivated and then labeled with CFSE in vitro. C57BL/6J mice were placed to75% hyperoxia chamber from P7 to P12 to establish OIR model. At P12, OIR mice were intravitreally injected with1 μL suspension contained 2×105EPCs（EPCs group） or isometric phosphate buffered saline（PBS group）. The contralateral eye of each mice received no injection（OIR group）. Evans blue angiography and frozen section were examined to track the labeled cells in OIR group at P15 and P19. Using retina paraffin sections and adenosinediphos phatase staining at P12 and P19, the effect of EPCs on OIR mice was evaluated quantitatively and qualitatively. RESULTS： The retinas from EPCs group with less non-perfusion area and fewer peripheral tufts wereobserved at P19, comparing with that from PBS or OIR group. The retinopathy in EPCs group receded earlier with less non-ganglion cells and neovascular nuclei,together with relatively regular distribution. The counts of the neovascular nuclei at P19 were reduced by 44% or45%, compared with those of OIR group or PBS group respectively. Three days after EPCs injection, a large number of EPCs appeared in the vitreous cavity and adhered to the retinal surface. While at one week, the cells gathered between the internal plexiform layer and the inner limiting membrane, and some EPCs appeared in retinal vessels.CONCLUSION： EPCs transplantation can participate in the reparative procedure of the neovascularization in OIR.

Isolation of Cultured Endothelial Progenitor Cells in vitro from PBMCs and CD133^+ Enriched Cells

Two isolation methods for sorting of endothelial progenitor cells(EPCs):from peripheral blood mononuclear cells(PBMCs)and CD133+ enriched cells were compared,by defining the cell morphology,phenotype,reproductive activities and function in vitro,to provide a reference for clinical application of EPCs.PBMCs from healthy subjects were used either directly for cell culture or for CD133+ sorting.The two groups of cells were cultured in complete medium 199(M199)for 7 to 14 days and the phenotypes of EPCs were an...

Effect of Intracoronary Infusion of Bone Marrow Mononuclear Cells or Peripheral Endothelial Progenitor Cells on Myocardial Ischemia-reperfusion Injury in Mini-swine

Objective To simulate and assess the clinical effect of intracoronary infusion of bone marrow mononuclear cells or peripheral endothelial progenitor cells on myocardial reperfusion injury in mini-swine model. Methods Twenty-three mini-swine with myocardial reperfusion injury were used as designed in the study protocol. About （3.54±0.90）×10^7 bone marrow mononuclear cells （MNC group, n=9） or （1.16± 1.07）× 10^7 endothelial progenitor cells （EPC group, n=7） was infused into the affected coronary segment of the swine. The other mini-swine were infused with phosphate buffered saline as control （n=7）. Echocardio- graphy and hemodynamic studies were performed before and 4 weeks after cell infusion. Myocardium infarc- tion size was calculated. Stem cell differentiation was analyzed under a transmission electromicroscope. Results Left ventricular ejection fraction dropped by 0% in EPC group, 2% in MNC group, and 10% in the control group 4 weeks after cell infusion, respectively （P〈0.05）. The systolic parameters increased in MNC and EPC groups but decreased in the control group. However, the diastolic parameters demonstrated no significant change in the three groups （P〉0.05）. EPC decreased total infarction size more than MNC did （1.60±0.26 cm2 vs. 3.71±1.38 cm2, P〈0.05）. Undermature endothelial cells and myocytes were found under transmission electromlcroscope. Conclusions Transplantation of either MNC or EPC may be beneficial to cardiac systolic function, but might not has obvious effect on diastolic function. Intracoronary infusion of EPC might be better than MNC in controlling infarction size. Both MNC and EPC may stimulate angiogenesis, inhibit flbrogenesis, and differentiate into myocardial cells.

Effects of Sirt1 on proliferation,migration,and apoptosis of endothelial progenitor cells in peripheral blood of SD rats with chronic obstructive pulmonary disease

Objective:To explore the effect of Sirt1 on the function of endothelial progenitor cells(EPCs)in rats with chronic obstructive pulmonary disease(COPD).Methods:A rat COPD model was established via smoking and endotoxin administration for three months.The peripheral circulating EPCs were isolated by gradient centrifugation,and their functions,cell cycle distribution,apoptosis,and Sirt1 expression were examined.The function changes of EPCs in the presence or absence of Sirt1 agonist and inhibitor were estimated;meanwhile,the expressions of Sirt1,FOXO3a,NF-κB,and p53 were also evaluated.Results:The proliferation,adhesion,and migration of EPCs decreased while the apoptosis rate was increased in the COPD rats.The expression of Sirt1 protein in EPCs of the COPD group was significantly lower than that in the control group(P<0.01).The overexpression of the Sirt1 gene using a gene transfection technique or Sirt1 agonists(SRT1720)improved the proliferation,migration,and adhesion,and decreased the apoptosis of EPC.However,Sirt1 inhibitor(EX527)decreased EPC functions in the COPD group.The effect of Sirt1 expression on EPC function may be related to reduction of FOXO3a and increase of NF-κB and p53 activity.Conclusions:Increased expression of Sirt1 can improve the proliferation and migration of EPCs and reduce their apoptosis in COPD rats.This change may be related to FOXO3a,NF-κB,and p53 signaling pathways.

Prognostic,diagnostic and therapeutic potential of endothelial progenitor cells for patients with ischaemic stroke:Hype or Hope

Ischaemic stroke is a debilitating disease with immense personal,societal and economic impact.Thrombolysis with recombinant tissue plasminogen activator remains the only approved pharmacotherapy for this disease.As each year less than 1%of eligible patients receive this therapy worldwide,efficacious new therapeutics are desperately needed.Emerging evidence suggest endothelial progenitor cells(EPCs),capable of repairing damaged vasculature,as one such therapeutics.However,questions regarding their optimal dose,delivery route and in vivo survivability remain largely unanswered.Outgrowth endothelial cells,generated in large numbers by ex vivo expansion of EPCs,enable effective assessment of these issues and may eventually serve as off-the-shelf therapeutics.Correlations between circulating EPC levels and stroke outcome imply that EPCs may also serve as clinical biomarkers for stroke.This viewpoint briefly evaluates the current evidence,pinpoints the gaps in the literature and proposes new directions for research.

Comparison of three fluorescence labeling and tracking methods of endothelial progenitor cells in laser-injured retina

AIM： To compare three kinds of fluorescent probes for in vitro labeling and in vivo tracking of endothelial progenitor cells（EPCs） in a mouse model of laser-induced retinal injury.METHODS： EPCs were isolated from human umbilical cord blood mononuclear cells and labeled with three different fluorescent probes： 5-（and-6）-carboxyfluorescein diacetate succinimidyl ester（CFSE）, 1,1′-dilinoleyl-3,3,3′,3′-tetramethylindo-carbocyanine perchlorate linked acetylated low-density lipoprotein（Di I-Ac LDL）, and green fluorescent protein（GFP）. The fluorescent intensity of EPCs was examined by confocal microscopy. Survival rate of labeled EPCs was calculated with trypan blue staining, and their adhesive capability was assessed. A mouse model of retinal injury was induced by laser, and EPCs were injected into the vitreous cavity. Frozen section and fluorescein angiography on flat-mounted retinal samples was employed to track the labeled EPCs in vivo.RESULTS： EPCs labeled with CFSE and Di I-Ac LDL exhibited an intense green and red fluorescence at the beginning; the fluorescence intensity decreased gradually to 20.23% and 49.99% respectively, after 28 d. On the contrary, the florescent intensity of GFP-labeled EPCs increased in a time-dependent manner. All labeled EPCs showed normal morphology and no significant change in survival and adhesive capability. In the mouse model, transplantation of EPCs showed a protective effect against retinal injury. EPCs labeled with CFSE and Di I-Ac LDL were successfully tracked in mice during the development of retinal injury and repair; however, GFP-labeled EPCs were not detected in the laser-injured mouse retina.CONCLUSION： The three fluorescent markers used in this study have their own set of advantages and disadvantages. CFSE and Di I-Ac LDL are suitable for short-term EPClabeling, while GFP should be used for long-term labeling. The choice of fluorescent markers should be guided by the purpose of the study.