Exogenous Endothelial Progenitor Cells Research Articles

Exogenous endothelial progenitor cells reached the deficient region of acute cerebral ischemia rats to improve functional recovery via Bcl-2.

As discovered in our previous study, autologous endothelial progenitor cells (EPCs) protect against acute focal ischemia rat via the promotion of angiogenesis. However, it is unknown whether the EPCs that reached the deficient region were transplanted ones or the products of other auto-conversion cells they had promoted. This study aimed to gather direct evidence for determining if exogenous transplanted EPCs directly participate in angiogenesis in ischemic areas and attempted to clarify the related mechanism. First, EPCs were extracted in vitro from male rats, which were characterized by uptake of fluorescently labeled acetylated low-density lipoprotein (ac-LDL) intake and Ulex europaeus agglutinin (UEA-1) and subsequently introduced to middle cerebral artery occlusion (MCAO) female rats for 7 days after ischemia surgery. The EPC-treated animals received approximately 1×106 cells, while the control animals received phosphate buffered saline (PBS). The animals behavior function recovery were by a rotarod (TOR) test, while infarct volume was assessed by brain magnetic resonance imaging (MRI). CD31 antibody was used to determine the presence of EPCs in the ischemic zone, and sex-determining region Y (SRY) gene in-situ hybridization (ISH) traced the EPC process. In addition, immunohistochemistry and Western blot were used to assess B-cell lymphoma 2 (Bcl-2) expression in the ischemic brain. Behavior tests and MRI of all ischemic stroke groups on postoperative day 14 indicated that EPCs were more effective in behavior function recovery and reducing infarct volume and gliosis status than the control group. Cluster of differentiation (CD31) immunofluorescent staining and SRY gene ISH demonstrated that EPCs yielded a better outcome in both angiogenesis and exogenous cell homing status. We also observed increased Bcl-2 distribution and higher plasma Bcl-2 levels in the EPC-treated group compared to the control group. Our results provide direct evidence that exogenous EPCs can participate in angiogenesis to improve neurological outcome and revascularization directly after stroke, with Bcl-2 playing an important role in this process.

Exosomes from Endothelial Progenitor Cells Improve the Outcome of a Murine Model of Sepsis.

Microvascular dysfunction leads to multi-organ failure and mortality in sepsis. Our previous studies demonstrated that administration of exogenous endothelial progenitor cells (EPCs) confers protection in sepsis as evidenced by reduced vascular leakage, improved organ function, and increased survival. We hypothesize that EPCs protect the microvasculature through the exosomes-mediated transfer of microRNAs (miRNAs). Mice were rendered septic by cecal ligation and puncture (CLP), and EPC exosomes were administered intravenously at 4hr after CLP. EPC exosomes treatment improved survival, suppressing lung and renal vascular leakage, and reducing liver and kidney dysfunction in septic mice. EPC exosomes attenuated sepsis-induced increases in plasma levelsof cytokines and chemokine. Moreover, we determined miRNA contents of EPC exosomes with next-generation sequencing and found abundant miR-126-3p and 5p. We demonstrated that exosomal miR-126-5p and 3p suppressed LPS-induced high mobility group box 1 (HMGB1) and vascular cell adhesion molecule 1 (VCAM1) levels, respectively, in human microvascular endothelial cells (HMVECs). Inhibition of microRNA-126-5p and 3p through transfection with microRNA-126-5p and 3p inhibitors abrogated the beneficial effect of EPC exosomes. The inhibition of exosomal microRNA-126 failed to block LPS-induced increase in HMGB1 and VCAM1 protein levels in HMVECs and negated the protective effect of exosomes on sepsis survival. Thus, EPC exosomes prevent microvascular dysfunction and improve sepsis outcomes potentially through the delivery of miR-126.

Exogenous endothelial progenitor cells contribute to hepatocellular carcinoma vasculogenesis in nude mouse

Objective To investigate the homing specificity of bone marrow (BM)-derived endothelial progenitor cells (EPCs) of transgenic mice carrying enhanced green fluorescent protein (EGFP) using a murine intraperitoneal hepatocellular carcinoma (HCC) model and its potential clinical value. Methods BM mononuclear cells were isolated by ficoll density-gradient centrifugation and serial differential adhesion method was used to purify the EPCs carrying EGFP which had been identified by morphology, uptake of DiI-Ac-LDL, binding of UEA-1 lection, flow cytometry and in vitro tube formation. Ex vivo expanded mouse BM-derived EGFP-EPCs were randomly injected into tumor-bearing nude mouse and normal nude mouse via the tail vein. Two weeks after injection of EPCs, the livers and other organs in each group were examined for distribution of transplanted EPCs. Results Fluorescence image analysis revealed that systemically transplanted EPCs 'homed’ to HCC with significantly higher specificity, respectively, in the number of cells in the experimental group were 169.40±10.87 in the livers, 15.40±2.87 in the heart, 14.70±2.02 in the lung, 1.70±0.50 in the kidney, 28.30±4.20 in the spleen, 6.90±1.31 in the pancreas, and 4.60±1.22 in the intestine, and those in the control group were respectively 76.50±4.20, 16.70±1.32, 76.00±3.31, 24.70±1.70, 77.90±4.50, 18.60±2.00 and 12.70±1.70 correspondingly. The number of cells in the liver more than lung (P=0.001), heart (P=0.032), kidney (P=0.002), spleen(P=0.036), pancreas (P=0.001)and bowel(P=0.001), the number of lung and spleen cells was higher in heart(P=0.036), pancreas (P=0.010), kidney (P=0.030) and bowel(P=0.008). as compared to other organs within the experimental group and to anatomically matched liver sections from the control groups (P=0.001). The quantify of EGFP-EPCs in lungs and spleen were higher specificity as compared to other organs (no liver). Immunohischemical showed the transplanted cells differentiate into vascular cells and recruitmented tumor angiogenesis. Conclusion The results suggested that the autologous EPCs in vivo could be recruited specifically into HCC, and take part in the angiogenesis of HCC in the nude mice. Key words: Endothelial progenitor cell; Carcinoma, hepatocellular; Cell transplantation; Vasculogenesis; Angiogenesis

Endothelial progenitor cells induce transplant arteriosclerosis via VEGFR-1/2 activity

Background: Acute rejection (AR) after organ transplantation results in transplant arteriosclerosis (TA). Endothelial progenitor cells (EPCs) are involved in tissue repair and blood vessel formation but are suspected to be a cause of TA. Methods: In this study, we introduced a syngeneic and allogeneic abdominal aortic transplant model with C57BL/6 and BALB/c mice. Syngeneic and allogeneic grafts were histopathologically analyzed after transplantation. Bone marrow-derived EPCs were injected into transplant model animals to observe their distribution and temporal concentration changes. Changes of vascular endothelial growth factor receptor 1 (VEGFR-1), phosphorylated VEGFR-1 (pVEGFR-1), VEGFR-2, pVEGFR-2, protein kinase B (Akt), pAkt, extracellular signal-regulated kinase 1 (Erk1), pErk1 levels in EPCs upon VEGF165 and the VEGFR inhibitor Vandetanib exposure were analyzed in vitro with western blotting. Results: In the allogeneic transplant group, two weeks after transplantation, formations of new intima layers could be observed, and its proliferation gradually increased to four and six weeks post-transplantation (p < 0.05), accompanied by significant arterial stenoses. Exogenous EPCs mainly localized to the damaged sites of the transplant arteries. In vivo, Vandetanib caused a significant dose dependent decrease of transplant hyperplasia (p < 0.05) and inhibited VEGF related proliferation, migration and adhesion of EPCs. Conclusion: Vandetanib treatment can reduce arteriosclerosis induced by abdominal aorta transplantation by blocking VEGFRs in EPCs.

Specific role of impaired glucose metabolism and diabetes mellitus in endothelial progenitor cell characteristics and function.

The disease burden of diabetes mellitus (DM) and its associated cardiovascular complications represent a growing and major global health problem. Recent studies suggest that circulating exogenous endothelial progenitor cells (EPCs) play an important role in endothelial repair and neovascularization at sites of injury or ischemia. Both experimental and clinical studies have demonstrated that hyperglycemia related to DM can induce alterations to EPCs. The reduction and dysfunction of EPCs related to DM correlate with the occurrence and severity of microvascular and macrovascular complications, suggesting a close mechanistic link between EPC dysfunction and impaired vascular function/repair in DM. These alterations to EPCs, likely mediated by multiple pathophysiological mechanisms, including inflammation, oxidative stress, and alterations in Akt and the nitric oxide pathway, affect EPCs at multiple stages: differentiation and mobilization in the bone marrow, trafficking and survival in the circulation, and homing and neovascularization. Several different therapeutic approaches have consequently been proposed to reverse the reduction and dysfunction of EPCs in DM and may represent a novel therapeutic approach to prevent and treat DM-related cardiovascular complications.

A new mosaic pattern in glioma vascularization: exogenous endothelial progenitor cells integrating into the vessels containing tumor-derived endothelial cells.

Emerging evidence suggests that glioma stem-like cells (GSCs) transdifferentiating into vascular endothelial cells (ECs) possibly contributes to tumor resistance to antiangiogenic therapy. Endothelial progenitor cells (EPCs), showing active migration and incorporation into neovasculature of glioma, may be a good vehicle for delivering genes to target GSCs transdifferentiation. Here, we found a new mosaic pattern that exogenous EPCs integrated into the vessels containing the tumor-derived ECs in C6 glioma rat model. Further, we evaluated the effect of these homing EPCs on C6 glioma cells transdifferentiation. The transdifferentiation frequency of C6 glioma cells and the expressions of key factors on GSCs transdifferentiation, i.e. HIF-1α, Notch1, and Flk1 in gliomas with or without EPCs transplantation showed no significant difference. Additionally, magnetic resonance imaging could track the migration and incorporation of EPCs into glioma in vivo, which was confirmed by Prussian blue staining. The number of magnetically labeled EPCs estimated from T2 maps correlated well with direct measurements of labeled cell counts by flow cytometry. Taken together, our findings may provide a rational base for the future application of EPCs as a therapeutic and imaging probe to overcome antiangiogenic resistance for glioma and monitor the efficacy of this treatment.

The Renoprotective Effect of Bone Marrow-Derived Endothelial Progenitor Cell Transplantation on Acute Ischemia-Reperfusion Injury in Rats

ObjectiveTo investigate the renoprotective effects of exogenous endothelial progenitor cells (EPCs) on acute renal ischemia-reperfusion (I/R) injury in rats. MethodsEPCs were collected by in vitro culture of mononuclear cells derived from rat bone marrow. The EPC labeling was performed using chloromethyl-benzamidodialkylcarbocyanine (CM-Dil). Sprague-Dawley rats were equally randomized into an I/R, an EPC, and a control group. We evaluated blood urea nitrogen (BUN) and serum creatinine (Scr), kidney morphology, apoptosis and microvessel density. EPC homing into I/R injured kidneys was observed using a fluorescence microscope. ResultsAfter EPC transplantation, CM-Dil-labeled EPCs were noted at the corticomedullary junction of injured kidneys. The levels of BUN and Scr were markedly lower among the EPC than the I/R group (P < .05). The histopathologic score was higher in the I/R than the EPC group (P < .05). Apoptosis of tubular epithelial cells was substantially reduced among EPC-treated rats (P < .01). In addition, more CD34+ microvessels were documented among the EPC than the other two groups (P < .01). The expression levels of vascular endothelial growth factor (VEGF) were also increased greatly in the EPC group (P < .05). ConclusionTransplanted exogenous EPCs exert protective effects on renal function by maintaining the integrity of peritubular capillaries after I/R injury.

Effects of Magnetically Labeled Exogenous Endothelial Progenitor Cells on Cerebral Blood Perfusion and Microvasculature Alterations after Traumatic Brain Injury in Rat Model

Increasing evidence suggests that endothelial progenitor cells (EPCs), a subgroup of bone marrow hematopoietic stromal cells, play a critical role in neovascularization and tissue repair. To explore the effect of exogenous EPCs on the cerebral blood perfusion and microvessels in the injured region in rat model with traumatic brain injury (TBI). EPCs were collected from the spleens of healthy Sprague-Dawley rats. Fifty-four Sprague-Dawley rats were randomly divided into six groups. The controlled cortical impact TBI was performed. Spleen-derived exogenous EPCs labeled with super-paramagnetic iron oxide (SPIO) (SPIO-EPCs) were transplanted into the blood by tail vein of rats at 6 and 12 h after TBI, respectively. Magnetic resonance imaging (MRI) and computed tomography perfusion imaging were performed at various time points. Microvascular density was determined by immunohistochemistry. In SPIO-EPCs group, patchlike hypointensities were detected in the injured region at 24 h after transplantation, and the range of hypointensities tended to expand gradually over time on MRI, which was confirmed by Prussian blue staining. Computed tomography perfusion imaging parameters were gradually developed from hyperperfusion to normal, while, microvascular density was gradually increased during 72 to 168 h after injury. The values of these indices in SPIO-EPCs group were significantly lower than those in SPIO-alone group at the same time point, but no significant differences were found in different time groups. The intravenously transplanted EPCs diminish the brain injury through restoring cerebral blood perfusion and increasing the cerebral microvasculature in the injured region in rat model with TBI.

Contribution of bone marrow‐derived endothelial progenitor cells to neovascularization and astrogliosis following spinal cord injury

Spinal cord injury causes initial mechanical damage, followed by ischemia-induced, secondary degeneration, worsening the tissue damage. Although endothelial progenitor cells (EPCs) have been reported to play an important role for pathophysiological neovascularization in various ischemic tissues, the EPC kinetics following spinal cord injury have never been elucidated. In this study, we therefore assessed the in vivo kinetics of bone marrow-derived EPCs by EPC colony-forming assay and bone marrow transplantation from Tie2/lacZ transgenic mice into wild-type mice with spinal cord injury. The number of circulating mononuclear cells and EPC colonies formed by the mononuclear cells peaked at day 3 postspinal cord injury. Bone marrow transplantation study revealed that bone marrow-derived EPCs recruited into the injured spinal cord markedly increased at day 7, when neovascularization and astrogliosis drastically occurred in parallel with axon growth in the damaged tissue. To elucidate further the contribution of EPCs to recovery after spinal cord injury, exogenous EPCs were systemically infused immediately after the injury. The administered EPCs were incorporated into the injured spinal cord and accelerated neovascularization and astrogliosis. These findings suggest that bone marrow-derived EPCs may contribute to the tissue repair by augmenting neovascularization and astrogliosis following spinal cord injury.

Combined Therapy with Sonic Hedgehog Gene Transfer and Bone Marrow-Derived Endothelial Progenitor Cells Enhances Angiogenesis and Myogenesis in the Ischemic Skeletal Muscle

We have previously demonstrated that sonic hedgehog (Shh) gene transfer improves angiogenesis in the setting of ischemia by upregulating the expression of multiple growth factors and enhancing the incorporation of endogenous bone marrow (BM)-derived endothelial progenitor cells (EPCs). In this study, we hypothesized that combined therapy with Shh gene transfer and BM-derived EPCs is more effective than Shh gene therapy alone in an experimental model of peripheral limb ischemia. We used old mice, which have a significantly reduced angiogenic response to ischemia, and compared the ability of Shh gene transfer, exogenous EPCs, or both to improve regeneration after ischemia. We found a significantly higher capillary density in the Shh + EPC-treated muscles compared to the other experimental groups. We also found that Shh gene transfer increases the incorporation and survival of transplanted EPCs. Finally, we found a significantly higher number of regenerating myofibers in the ischemic muscles of mice receiving combined treatment with Shh and BM-derived EPCs. In summary, the combination of Shh gene transfer and BM-derived EPCs more effectively promotes angiogenesis and muscle regeneration than each treatment individually and merits further investigation for its potential beneficial effects in ischemic diseases.

The Effects of Magnetically Labeled Rat Spleen-originated Endothelial Progenitor Cells on Growth of Glioma in Vivo: An Experimental Study

The aim of this study was to investigate the effects of exogenous endothelial progenitor cells (EPCs) on the growth and invasiveness of glioma in vivo to provide an experimental basis for the value and safety of using magnetically labeled EPCs as target vectors to detect early infiltration of glioma. EPCs were collected from the spleens of healthy Sprague-Dawley rats, made EPCs conditioned medium after identification. Four models of Sprague-Dawley rat glioma (60 rats in total) were established as a control and three experimental groups (group A, B, and C). In the control group, orthotopic transplantation of C6 glioma cells was performed. Compared to the control group, EPCs conditioned medium was added in group A and P7228-labeled EPCs were added in group B. In group C, P7228-labeled EPCs were transplanted via the tail vein. Magnetic resonance imaging and perfusion-weighted imaging were performed on several days. Tumor microvascular density and vascular endothelial growth factor expression were determined through immunohistochemistry. In group C, hypointense areas were detected at the periphery of the tumor on the first day after transplantation of EPCs, and more hypointense areas were found inside the tumor over time. Tumor size in all four groups developed significantly with increasing time (P < .01), but there was no marked difference among these groups at the same time (P > .05). No remarkable differences in microvascular density and cells positive for vascular endothelial growth factor were found at the same time among the four groups (P > .05). Both magnetic resonance imaging and immunohistochemical findings confirmed that exogenous EPCs could not affect the biologic behavior of C6 glioma cells in vivo through a paracrine effect or by direct cellular interaction. Therefore, exogenous EPCs could not exert significant promoting effects on glioma growth.

Cilostazol enhances integrin‐dependent homing of progenitor cells by activation of camp‐dependent protein kinase in synergy with Epac1

Recruitment and adhesion of exogenous endothelial progenitor cells (EPCs) or endogenously mobilized bone marrow mononuclear cells (BM MNCs) to the sites of ischemia is an important focus of cell therapy. This study sought to determine whether cilostazol enhances integrin-dependent homing of progenitor cells both in vitro and in vivo. In the in vitro experiments with human umbilical cord blood (HUCB)-derived EPCs, cilostazol (10 μM) stimulated up-regulation of integrins β1, α1, and αv as well as 8-pCPT-2'-O-Me-cAMP (100 μM; 8-pCPT, Epac activator). Cilostazol and 8-pCPT significantly enhanced migration and adhesion of HUCB EPCs to a fibronectin-coated plate and endothelial cells, which were inhibited by KT5720 (PKA inhibitor, 1 μM) and GGTI-298 (Rap1 inhibitor, 20 μM). Cilostazol stimulated Epac1 expression and up-regulated the active Rap1, as did 8-pCPT, and they were suppressed by KT5720 (P < 0.001) and GGTI-298 (P < 0.001). 8-pCPT increased p-CREB expression and stimulated PKA activity, which was inhibited by KT5720, Rp-cAMPS, and GGTI-298. In addition, N(6)-benzoyl-cAMP (100 μM) increased Rap1 GTP expression, as did 8-pCPT; they were suppressed by Rp-cAMPS and GGTI-298. The in vivo experiments showed that cilostazol (30 mg/kg/day, orally for 7 days) significantly enhanced the integrin β1 expression in the molecular layer and up-regulated homing of BM MNCs to the injured molecular layer with increased capillary density in mouse brain subjected to transient forebrain ischemia (n = 6, P < 0.001). In conclusion, cilostazol stimulated integrin expression and enhanced migration and adhesion of progenitor cells through cooperative activation of PKA and Epac signals; such activity may improve the efficacy of cell therapy for ischemic disease.

Distribution of exogenous endothelial progenitor cells in a rat model of hepatoma and their impact on liver cancer formation

Distribution of exogenous endothelial progenitor cells in a rat model of hepatoma and their impact on liver cancer formation

The recruitment of exogenous endothelial progenitor cells in lung tumor model of nude mice

Endothelial progenitor cells (EPCs) play an important role in hypoxia-triggered tumor vasculogenesis. However, the homing of exogenous EPCs in tumors is still unclear. In this study, we investigated the recruitment of exogenous EPCs in human lung adenocarcinoma model of nude mice. EPCs labeled with green fluorescence protein (GFP) were transplanted into nude mice bearing human lung adenocarcinoma. The growth of tumor was observed. After the mice were killed, GFP-EPCs in different tissues were examined by fluorescence. The tumor tissues were stained for CD133, hypoxia-inducible factor-1alpha (HIF-1α), stromal cell-derived factor-1α (SDF-1α), and vascular endothelial growth factor receptor (KDR). Real-time polymerase chain reaction of CD133, HIF-1α, SDF-1α, and VEGF-1 were also performed. The growth of tumor in EPC group was significantly faster than that in saline solution group (P <0.05). Under fluorescence microscope, GFP-EPCs were strongly expressed in both tumor and bone marrow. EPCs were recruited to the tumor periphery to participate in tumor vasculogenesis. The expression of CD133, HIF-1α, and SDF-1 mRNA in tumor and bone marrow were significantly higher than that in the liver, spleen, and skin (P<0.05). Exogenous EPCs can be recruited to tumor and accelerate tumor growth. Except tumor, bone marrow can also recruit EPCs.

Human umbilical cord blood endothelial progenitor cells decrease vein graft neointimal hyperplasia in SCID mice

AimsVein graft endothelial damage is a key step in the development of neointimal hyperplasia, leading to vein graft failure. We sought to determine whether exogenous endothelial progenitor cells could promote vein graft re-endothelialization, and thereby ameliorate neointimal hyperplasia. Methods and resultsCarotid artery interposition grafting was performed with syngeneic inferior vena cavae in mice with severe combined immunodeficiency (SCID). Lineage-negative human umbilical cord blood (hUCB) cells (or medium alone) were injected into vein-grafted mice intra-operatively and 2 weeks post-operatively. In vein grafts from hUCB cell-injected mice, we found human HLA-expressing endothelial cells, as well as increased levels of VEGF and FGF-2. Furthermore, hUCB cells secreted VEGF and FGF-2 in vitro. The markedly enhanced endothelial regeneration, likely resulting from both direct engraftment and paracrine actions of hUCB cells, inhibited inflammatory response, diminished intimal cell proliferation, and reduced neointimal hyperplasia in the vein grafts. ConclusionshUCB cells may accelerate vein graft re-endothelialization via both direct differentiation into endothelial cells and release of paracrine factors to enhance endothelial regeneration and reduce inflammation. These data highlight a potential therapeutic role for cellular therapy in vessel injury.

Abstract 2897: Targeting Engraftment of Endothelial Progenitor Cells to Ischemic Tissue by Ultrasound-mediated Transfection of Stromal Cell Derived Factor-1

The homing of endothelial progenitor cells (EPC) to sites of ischemic injury is critical to successful neovascularization. We hypothesize that ultrasound-mediated (UM) transfection of stromal-cell derived factor-1 (SDF-1) would enhance engraftment of exogenously administered EPCs and improve neovascularization in a rat model of chronic hindlimb ischemia. Methods: Bone-marrow derived EPCs were isolated from donor F344 rats, cultured for 7 days, labelled with CMTMR and injected (1 x 10 6 ) into recipient animals via a jugular vein. Unilateral hindlimb ischemia was created by iliac artery ligation in 32 rats. At day 14 post ligation, microvascular blood volume (MBV) and blood flow (MBF) in the hindlimb muscles were assessed by contrast-enhanced ultrasound (CEU). Rats were assigned to 4 treatment groups: control untreated animals, EPCs alone, UM delivery of SDF-1 plasmid (500 μg DNA + 1x10 9 cationic microbubbles), and both UM delivery of SDF-1 + EPCs (n=8 per group). Perfusion was re-assessed at day 28. EPC engraftment was assessed using fluorescent microscopy. Circulating exogenous EPC numbers were determined by FACS at various time-points post injection. Results: Prior to EPC delivery, normalized MBV and MBF in ischemic muscle were similarly reduced in all groups. Control animals showed no changes in perfusion over time. By day 28, EPC treated animals had a significant increase in normalized MBV (1.04±0.24 vs 0.67±0.22, p&lt;0.001), without significant improvements in MBF (0.44±0.13 vs 0.33±0.15, p=NS), while SDF-1/EPC treated animals had significant improvement in both normalized MBV (1.33±0.51 vs 0.67±0.22, p&lt;0.001), and MBF (0.55±0.26 vs 0.33±0.15, p&lt;0.001). Maximal exogenous circulating EPCs could be detected at 72 hours post injection. Fluorescent microscopy showed little to no CMTMR labelled cells in the non-ischemic hindlimb in all groups. In comparison, a rich population of cells was found in the ischemic hindlimb of both the SDF-1/EPC and EPC treated animals, with the SDF-1/EPC animals demonstrating the greatest density of EPCs. Conclusions: Ultrasound-mediated transfection of SDF-1 improves intravenous EPC targeting, enhancing EPC engraftment into chronically ischemic tissue and leading to greater neovascularization response.

The role of angiogenesis in damage and recovery from ischemic stroke

Ischemic stroke is burdened with a high morbidity and mortality in our society. However, there are few effective and largely available therapies for this devastating disease. In additon to advancing acute reperfusion therapies, there is a need to develop treatments aimed to promote repair and regeneration of brain tissue damaged by ischemia (neurorecovery). Therapeutic angiogenesis and vasculogenesis represent novel approaches of regenerative medicine that may help in the cure of patients with acute ischemic stroke. Translation of our knowledge about these processes from the bench to bedside is still underway. Although angiogenesis (the sprouting of new blood vessels from pre-existing vascular structures) is likely to contribute to neurorepair, the finality of the angiogenic response in acute ischemic stroke has not been fully elucidated. The first therapeutic approach to angiogenesis after ischemic stroke would be the modulation of the endogenous angiogenic response. In this setting, early instauration of physical activity, statins, and peroxisome proliferator-activated receptor-gamma agonists may enhance angiogenesis and neuroregeneration. Gene therapy with vascular growth factors has been successfully tested in patients affected by chronic myocardial and peripheral ischemia. Regarding brain ischemia, experiments in animal models have shown that the effect of these growth factors is critically affected by the dosage, route of delivery, and time of administration in relation to stroke onset. In addition, the optimal angiogenic substance is unknown. Finally, vectors for gene transfer should be further optimized. Therapeutic vasculogenesis consists of the administration of exogenous endothelial progenitor cells in order to enhance brain repair processes. Endothelial progenitor cells may be recruited in response to cerebral ischemia and participate in reparative vasculogenesis after acute ischemic stroke. Further research is needed to clarify their role and therapeutic applicability in human brain ischemia.