Release Of Endothelial Progenitor Cells Research Articles

Exercise Training Effects on Circulating Endothelial and Progenitor Cells in Heart Failure

Heart failure (HF) is a major public health issue worldwide with increased prevalence and a high number of hospitalizations. Patients with chronic HF and either reduced ejection fraction (HFrEF) or mildly reduced ejection fraction (HFmrEF) present vascular endothelial dysfunction and significantly decreased circulating levels of endothelial progenitor cells (EPCs). EPCs are bone marrow-derived cells involved in endothelium regeneration, homeostasis, and neovascularization. One of the unsolved issues in the field of EPCs is the lack of an established method of identification. The most widely approved method is the use of monoclonal antibodies and fluorescence-activated cell sorting (FACS) analysis via flow cytometry. The most frequently used markers are CD34, VEGFR-2, CD45, CD31, CD144, and CD146. Exercise training has demonstrated beneficial effects on EPCs by increasing their number in peripheral circulation and improving their functional capacities in patients with HFrEF or HFmrEF. There are two potential mechanisms of EPCs mobilization: shear stress and the hypoxic/ischemic stimulus. The combination of both leads to the release of EPCs in circulation promoting their repairment properties on the vascular endothelium barrier. EPCs are important therapeutic targets and one of the most promising fields in heart failure and, therefore, individualized exercise training programs should be developed in rehabilitation centers.

Sphingosine-1-Phosphate Improves the Biological Features of Mouse Bone Marrow-Derived EPCs Partially through PI3K/AKT/eNOS/NO Pathway.

Sphingosine-1-phosphate (S1P), a bioactive sphingolipid, is recognized as a critical regulator in physiological and pathophysiological processes of atherosclerosis (AS). However, the underlying mechanism remains unclear. As the precursor cells of endothelial cells (ECs), endothelial progenitor cells (EPCs) can prevent AS development through repairing endothelial monolayer impaired by proatherogenic factors. The present study investigated the effects of S1P on the biological features of mouse bone marrow-derived EPCs and the underlying mechanism. The results showed that S1P improved cell viability, adhesion, and nitric oxide (NO) release of EPCs in a bell-shaped manner, and migration and tube formation dose-dependently. The aforementioned beneficial effects of S1P on EPCs could be inhibited by the phosphatidylinositol 3-kinase (PI3K) inhibitor of LY294002 and nitric oxide synthase (NOS) inhibitor of N’-nitro-L-arginine-methyl ester hydrochloride (L-NAME). The inhibitor of LY294002 inhibited S1P-stimulated activation of phosphorylated protein kinase B (AKT) (p-AKT) and endothelial nitric oxide synthase (eNOS) (p-eNOS), and down-regulated the level of eNOS significantly. The results suggest that S1P improves the biological features of EPCs partially through PI3K/AKT/eNOS/NO signaling pathway.

Endothelial Progenitor Cells at the Interface of Chronic Kidney Disease: From Biology to Therapeutic Advancement.

The 'epidemic' diffusion of chronic kidney disease (CKD) needs the development of new therapeutic approaches to slow down the progression to end-stage renal disease. Endothelial Progenitor Cells (EPCs) are promising tools for the treatment of many human diseases as they promote the repair of damaged tissues. They were also suggested as therapy to repair renal tissue after an injury. Strategies using EPCs to induce a reparative process with functional restoring of a diseased kidney or to delay CKD are of two types: direct stem cells infusion or stimulating endogenous release of EPCs. The repair process following endothelial damage occurs in three steps: 1) mobilization from bone marrow; 2) homing on the sites of vascular injury; 3) incorporation of the endothelium into the injured blood vessels. In this narrative review we pointed our view to the role of EPCs in endothelial repair and the potential in retarding the progression to renal function loss. Physicians need the development of new preventive strategies for detecting patients at risk and discover renal damage. In this way they could slow, by a conservative therapy, the evolution of renal disease and decrease associated morbidity. EPCs have instead well recognized reparative capabilities in many organs. We summarized some recent preclinical and clinical models of EPCs mobilization during CKD and we emphasized the potential use of EPCs to slow the progression of renal disease.

Increased circulation mobilization of endothelial progenitor cells in preterm infants with retinopathy of prematurity

Retinopathy of prematurity (ROP) is a result of increased pathological neoangiogenesis of the retina in preterm infants. Cells responsible for the pathogenesis of ROP are unclear, but some evidence indicates that bone marrow derived cells are involved in this disorder. Endothelial progenitor cells (EPCs), play a role in angiogenesis in response to tissue ischemia or endothelial damage. In this study, the number of cEPCs in preterm infants with ROP was determined to identify whether the circulation mobilization of EPCs is associated with ROP. We evaluated 99 participants in this study: 22 preterm infants with ROP, 35 preterm infants without ROP, and 42 full-term infants. The release of EPCs in the circulation was first quantified. Thereafter, cEPCs were harvested and cultivated, then the biological features of these cells including migratory, proliferative, and tubulogenic activities were analyzed. The mRNA levels of some proangiogenic factors were also measured in preterm infants. Our results showed greater numbers of cEPCs in infants with ROP, which was associated with increased serum concentrations of angiogenic factors and with augmented proliferative, migratory, and tubulogenic activity of these cells. Western blotting showed increased protein levels of VEGF and HIF-α in cEPCs harvested from ROP infants. This study showed that ROP in preterm infants is associated with increased mobilization of EPCs into the circulation. Therefore, increased cEPCs along with elevated levels of angiogenic factors and tubulogenesis suggest that these cells may play a role in the development and progression of ROP.

The Improvement of Respiratory Performance After Phototherapy-Induced EPC Mobilization in Preterm Infants With RDS.

Many infants who develop bronchopulmonary dysplasia (BPD) are born with serious respiratory distress syndrome (RDS), which is associated with impaired vascular and alveolar growth. RDS is a breathing disorder that mostly affects preterm infants and occurs in infants whose lungs have not yet been fully developed. The use of surfactant in RDS treatment does not necessarily prevent BPD. Endothelial progenitor cells (EPCs) may contribute to lung angiogenesis for the prevention and treatment of BPD. The aim of this study was to evaluate the therapeutic efficacy of phototherapy for EPC release in preterm infants born with RDS. Seventy-five RDS preterm infants were divided into two groups: RDS with phototherapy and RDS without phototherapy. Respiratory indices were recorded for each patient. Circulating EPCs were isolated before and after phototherapy and colony forming efficiency, chemotactic, tubulogenic, proliferative, and functional properties of these cells were analyzed. Our results showed that phototherapy increased the release of EPCs into the circulation in RDS preterm infants, with augmentation of cell proliferation, tubulogenic, chemotactic, and proliferative properties of EPCs. Phototherapy-induced EPC release was associated with improved lung function as was recorded by significantly decrease in continuous positive airway pressure (CPAP) days, CPAP plus ventilator days, and PCO2 along with a significant increase in PO2 and PaO2 /FiO2 , resulting in markedly decreased rate of BPD occurrence in preterm infants with RDS. Overall, phototherapy is touted as a promising modality for the amelioration of respiratory performance and prohibition of BPD occurrence in RDS preterm infants. J. Cell. Biochem. 118: 594-604, 2017. © 2016 Wiley Periodicals, Inc.

Multilayer Membranes of Glycosaminoglycans and Collagen I Biomaterials Modulate the Function and Microvesicle Release of Endothelial Progenitor Cells.

Multilayer composite membrane of biomaterials can increase the function of adipose stem cells or osteoprogenitor cells. Recent evidence indicates endothelial progenitor cells (EPCs) and EPCs released microvesicles (MVs) play important roles in angiogenesis and vascular repair. Here, we investigated the effects of biomaterial multilayer membranes of hyaluronic acid (HA) or chondroitin sulfate (CS) and Collagen I (Col I) on the functions and MVs release of EPCs. Layer-by-layer (LBL) technology was applied to construct the multilayer composite membranes. Four types of the membranes constructed by adsorbing either HA or CS and Col I alternatively with different top layers were studied. The results showed that all four types of multilayer composite membranes could promote EPCs proliferation and migration and inhibit cell senility, apoptosis, and the expression of activated caspase-3. Interestingly, these biomaterials increased the release and the miR-126 level of EPCs-MVs. Moreover, the CS-Col I membrane with CS on the top layer showed the most effects on promoting EPCs proliferation, EPCs-MV release, and miR-126 level in EPCs-MVs. In conclusion, HA/CS and Collagen I composed multilayer composite membranes can promote EPCs functions and release of miR-126 riched EPCs-MVs, which provides a novel strategy for tissue repair treatment.

Stem Cell-Released Microvesicles and Exosomes as Novel Biomarkers and Treatments of Diseases.

Extracellular microvesicles (MVs) and exosomes (EXs) can mark the changes of their origin cells. They can transfer their carried messages (proteins, mRNAs, and microRNAs) to target cells to modulate the functions of the recipient cells. Therefore, MVs and EXs are recognized as potential biomarkers and important therapeutic targets or tools for a wide spectrum of diseases including vascular and neurological diseases and cancers [1–4]. While research in stem cells has achieved significant advances during the past decades, there is less information regarding the roles of MVs and EXs released from stem cells. The current special issue includes the selected reviews and original articles focusing on novel studies of stem cell-released MVs and EXs as biomarkers and treatments of cardiovascular and neurological diseases and cancers. There is an urgent need to identify sensitive and specific methods for the isolation and identification of MVs and EXs, which is very important and challenging. J. Wang et al. [5] have developed novel methods for analysis of exosomes released from endothelial cells (ECs) and endothelial progenitor cells (EPCs) by combining microbeads and fluorescence quantum dots (Q-dots®) techniques. The authors showed that anti-CD105/anti-CD144 and anti-CD34/anti-KDR had the highest sensitivity and specificity for isolating and detecting EC-EXs and EPC-EXs, respectively. A. Fricke et al. [6] evaluated whether MVs shed by synovial sarcoma cells carry the tumor-specific fusion gene SYT-SSX transcripts and revealed that these MVs might serve as a diagnostic biomarker for synovial sarcoma. They also noted that more sensitive assays are needed to detect cancer specific microvesicles in the peripheral blood of cancer patients. Leukemia stem cells (LSCs) are able to self-renew, proliferate, and differentiate extensively, which are crucial for the initiation and maintenance of acute myeloid leukemia (AML). AML is an aggressive disease characterized by rapid proliferation of immature myeloid cells. Y. Wang et al. [7] reported that LSCs-released MVs support AML cell malignance and targeting of miR34a could offer a new approach for the management of AML. Exosome-based therapy could overcome many limitations of cell-based strategy in safety, potency, efficacy, and scalability of stem cell products. The article by J. Burke et al. [8] reviewed the existing literature to highlight the current advances of stem cell-derived exosomes with particular attention to regenerative medicine in orthopaedics. A. Luarte et al. [9] provided a review on the potential therapies of stem cell-derived exosomes in CNS diseases by focusing on the neurogenic niche. This article discusses how the modulation of the adult neurogenic niches may be a therapeutic target. F. Alcayaga-Miranda et al. [10] provided a review article which discusses the current knowledge related to the angiogenic potential of exosomes of mesenchymal stem cells and methods to enhance their biological activities. H. Zhang et al. [11] performed meta-analysis based on the reports published between 2000 and 2015 to assess the clinical effectiveness of using exosomes in ischemia/reperfusion injury. They revealed that exosomes secreted from mesenchymal stem cells inhibit myocardial ischemia/reperfusion injury. Hepatic stellate cells (HSCs), also known as liver-specific mesenchymal stem cells (MSCs), contribute to liver regeneration. R. Huang et al. [12] showed that HSC-derived MVs dose-dependently protect hepatocytes from toxicant-induced injury. Although the molecular mechanisms have not been elucidated, the beneficial effects of MVs are likely through maintaining the proliferative activity and the antiapoptotic and antiautophagic abilities of hepatocytes. B. Dai et al. [13] investigated the effects of biomaterial multilayer membranes of hyaluronic acid (HA) or chondroitin sulfate (CS) and Collagen I (Col I) on the functions and MVs release of EPCs. They found that multilayer composite membranes composed of HA/CS and Collagen I composed multilayer composite membranes can promote EPCs functions and release of miR-126 rich EPCs-MVs, which provides a novel strategy for tissue repair treatment. Therefore, combined use of biomaterials and stem cells may present a novel approach for promoting wound healing and tissue regeneration. However, further investigations in animal models and patients are required. Stem cell-derived exosomes and MVs could be used as biomarkers of various diseases, as well as novel approaches to combat diseases. However, further experimentation must be done and more discoveries must be made in order for them to become available for clinical use. We hope that the original research articles and review articles presented in this special issue represent the current advances in this field, which will stimulate further in-depth exploration. Yanfang Chen Yaoliang Tang Weiwen Long Chunxiang Zhang

Effect of High-Dose Atorvastatin Reload on the Release of Endothelial Progenitor Cells in Patients on Long-Term Statin Treatment Who Underwent Percutaneous Coronary Intervention (from the ARMYDA-EPC Study)

Endothelial progenitor cells (EPCs) may concur to endogenous vascular repair. Previous studies have reported that statin treatment increases EPC levels. We investigated whether this occurs in patients on long-term statin treatment who underwent percutaneous coronary interventions (PCIs). In a phase A study, 53 patients (atorvastatin reload [AR] 80 mg 12 hours before + 40 mg 2 hours before PCI, n = 27; placebo [P], n = 26) were evaluated for EPC mobilization as CD45dim/CD34+/CD133+/KDR+ cell number by flow cytometry. Assays were run at randomization (12 hours before PCI, R), immediately before PCI (T0) at 8 (T8) and 24 hours (T24). In phase B study, 50 patients (AR, n = 25; P, n = 25) were evaluated for early colony formation by Hill colony forming unit (CFU) assay, with sampling at randomization and 24 hours later. In phase A, EPCs levels were similar at randomization between 2 arms (0.23% [0.14 to 0.54] of total events in AR vs 0.22% [0.04 to 0.37] in P group; p = 0.33). At PCI, EPC levels were higher in AR arm (0.42% [0.06 to 0.30] vs 0.19% [0.06 to 030]; p = 0.009). Higher EPC levels in AR group were also found at 8 and 24 hours. In phase B, EPC CFUs/well numbers at randomization were similar in the 2 arms (8 [6 to 12] in AR vs 12 [6 to 20] in P group, p = 0.109). EPC CFU/well at 24 hours became significantly higher in AR arm (17 [10 to 23] vs 5 [2 to 13], p = 0.002). In conclusion, high-dose AR before PCI in patients on long-term statin therapy promptly increases EPCs mobilization, which are capable of early colony formation and may contribute to cardioprotection.

Transplantation of cryopreserved human umbilical cord blood-derived endothelial progenitor cells induces recovery of carotid artery injury in nude rats

IntroductionTransplantation of endothelial progenitor cells (EPCs) restores endothelial function in patients with endothelial dysfunction and initial denudation. The goal of the present study was to determine the effect of cryopreserved human umbilical cord blood (UCB)-derived EPC infusion on the repair of carotid artery injury in nude rats.MethodsMononuclear cells (MNCs) from human cryopreserved UCB and peripheral blood (PB) of patients with cardiovascular diseases and healthy volunteers were cultured in a conditioned medium. The in vitro migration, proliferation, adhesion, and survival capacities, as well as paracrine cytokine release of EPCs were investigated. EPC homing, induced reendothelialization, and the effect on neointima formation were also assessed in vivo.ResultsPatient-derived PB EPCs (PPB-EPCs) displayed decreased migration, proliferation, adhesion, and survival capabilities as compared to PB-EPCs from healthy volunteers (HPB-EPCs) and cryopreserved UCB-EPCs. However, there was no difference in the release of vascular endothelial growth factor (VEGF) and stromal cell derived factor 1 (SDF-1) between the three groups. Two weeks after transplantation, more labeled UCB-EPCs and HPB-EPCs than PPB-EPCs were found by cell tracking in the injury zone. Administration of PPB-EPCs, HPB-EPCs, and UCB-EPCs enhanced reendothelialization and inhibited neointima formation compared to the saline control. However, UCB-EPC and HPB-EPC infusion showed a greater improvement than PPB-EPCs.ConclusionsCryopreserved UCB-MNCs derived EPCs and HPB-EPCs show better responses to cytokines and vascular injury than PPB-EPCs. Thus, cryopreservation and delivery of cryopreserved autogenous UCB-EPCs or HPB-EPCs may be a promising vasculoprotective approach for patients with multiple cardiovascular risk factors.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-015-0022-4) contains supplementary material, which is available to authorized users.

Exercise induces stromal cell-derived factor-1α-mediated release of endothelial progenitor cells with increased vasculogenic function.

Endothelial progenitor cells have been shown to traffic to and incorporate into ischemic tissues, where they participate in new blood vessel formation, a process termed vasculogenesis. Previous investigation has demonstrated that endothelial progenitor cells appear to mobilize from bone marrow to the peripheral circulation after exercise. In this study, the authors investigate potential etiologic factors driving this mobilization and investigate whether the mobilized endothelial progenitor cells are the same as those present at baseline. Healthy volunteers (n = 5) performed a monitored 30-minute run to maintain a heart rate greater than 140 beats/min. Venous blood samples were collected before, 10 minutes after, and 24 hours after exercise. Endothelial progenitor cells were isolated and evaluated. Plasma levels of stromal cell-derived factor-1α significantly increased nearly two-fold immediately after exercise, with a nearly four-fold increase in circulating endothelial progenitor cells 24 hours later. The endothelial progenitor cells isolated following exercise demonstrated increased colony formation, proliferation, differentiation, and secretion of angiogenic cytokines. Postexercise endothelial progenitor cells also exhibited a more robust response to hypoxic stimulation. Exercise appears to mobilize endothelial progenitor cells and augment their function by means of stromal cell-derived factor 1α-dependent signaling. The population of endothelial progenitor cells mobilized following exercise is primed for vasculogenesis with increased capacity for proliferation, differentiation, secretion of cytokines, and responsiveness to hypoxia. Given the evidence demonstrating positive regenerative effects of exercise, this may be one possible mechanism for its benefits.

Roles of heme oxygenase-1 promoting regeneration of peribiliary vascular plexus in bile duct ischemia/reperfusion injury

To study the effect of heme oxygenase-1 (HO-1) on peribiliary vascular plexus (PVP) in rat bile duct ischemia/reperfusion injury. Total 128 male SD rats were randomly divided into saline group (Saline), empty virus group (Adv), induced group (Adv-HO-1) and suppressed group (HO-1 siRNA), and there were 32 rats in each group. Rats were injected using 0.5 ml of saline, empty adenovirus, HO-1 adenovirus and siRNA adenovirus (2×10(9) TU/rat) via the dorsal penile vein 24 hours before surgery. Liver function was analyzed at 1 hour and 1, 7, 14 days after reperfusion. HO-1, hypoxiainducible factor-1α (HIF-1α), stromal cell derived factor-1α (SDF-1α) and vascular endothelial growth factor (VEGF) protein content was analyzed by Western blot. The endothelial progenitor cells (EPCs) ratio in the liver and peripheral blood was detected by flow cytometry. Small vascular around the bile duct was observed by α-smooth muscle actin and von Willebrand factor double immunofluorescence staining. Reduced liver injury and higher expression of HIF-1α, SDF-1α and VEGF in the induced group after surgery (q = 5.68-7.52, P < 0.01). EPCs ratio in the liver and peripheral blood was significantly higher in the induced group than saline group (q = 12.14 and 15.26, P < 0.01), and the suppressed group at 7 days after surgery were less than saline group significantly (q = 4.83 and 5.07, P < 0.01). In comparison to the suppressed group, higher density of small vascular around the bile duct was seen in the liver tissue of induced group. HO-1 can induce the expression of HIF-1α, SDF-1α and VEGF, and mobilize the release of EPCs to the peripheral from the bone marrow. EPCs migrate to the liver and promote damaged PVP repair and regeneration.

The Effects of Smoking on Levels of Endothelial Progenitor Cells and Microparticles in the Blood of Healthy Volunteers

BackgroundCigarette smoking, both active and passive, is one of the leading causes of morbidity and mortality in cardiovascular disease. To assess the impact of brief smoking on the vasculature, we determined levels of circulating endothelial progenitor cells (EPCs) and circulating microparticles (MPs) following the smoking of one cigarette by young, healthy intermittent smokers.Materials and Methods12 healthy volunteers were randomized to either smoking or not smoking in a crossover fashion. Blood sampling was performed at baseline, 1, 4 and 24 hours following smoking/not smoking. The numbers of EPCs and MPs were determined by flow cytometry. MPs were measured from platelets, leukocytes and endothelial cells. Moreover, MPs were also labelled with anti-HMGB1 and SYTO 13 to assess the content of nuclear molecules.ResultsActive smoking of one cigarette caused an immediate and significant increase in the numbers of circulating EPCs and MPs of platelet-, endothelial- and leukocyte origin. Levels of MPs containing nuclear molecules were increased, of which the majority were positive for CD41 and CD45 (platelet- and leukocyte origin). CD144 (VE-cadherin) or HMGB1 release did not significantly change during active smoking.ConclusionBrief active smoking of one cigarette generated an acute release of EPC and MPs, of which the latter contained nuclear matter. Together, these results demonstrate acute effects of cigarette smoke on endothelial, platelet and leukocyte function as well as injury to the vascular wall.

Regulation of Endothelial Progenitor Cell Release by Wnt Signaling in Bone Marrow

Endothelial progenitor cells (EPC) have been shown to participate in ischemia-induced retinal neovascularization (NV). Overactivation of Wnt signaling has a pathogenic role in ischemia-induced retinal NV. The purpose of this study is to determine whether Wnt signaling regulates EPC release. Oxygen-induced retinopathy (OIR) was used as a model of retinal NV and Wnt pathway activation. The EPC, marked as c-Kit(+)/Tie-2(+) cells in the peripheral blood and bone marrow, were quantified using flow cytometry following immunolabeling. The Wnt signaling activity was evaluated by measuring nonphosphorylated β-catenin levels and X-gal staining in the Wnt reporter mice (Bat-gal mice). The c-Kit(+)/Tie-2(+) cells were increased significantly in the peripheral blood and bone marrow of mice with OIR, compared to non-OIR mice. Overexpression of kallistatin, an endogenous inhibitor of the Wnt pathway, in kallistatin transgenic (kallistatin-TG) mice with OIR attenuated the increases of c-Kit(+)/Tie-2(+) cells in the peripheral blood and bone marrow, compared to WT mice with OIR. When the Bat-gal mice were crossed with kallistatin-TG mice, kallistatin overexpression suppressed the OIR-induced increases of X-gal-positive cells in the retinas and bone marrow, suggesting inhibition of Wnt signaling in these tissues. Furthermore, intraperitoneal injection of LiCl, a Wnt signaling activator, increased c-Kit(+)/Tie-2(+) cells in the peripheral blood of normal mice. Consistently, LiCl activated Wnt signaling in the retina and bone marrow cells in Bat-gal mice. The Wnt signaling pathway has an important role in EPC release during retinal NV in OIR.

Mobilization of Endothelial Progenitor Cells From Bone Marrow is Impaired in a Piglet Model of Acute Respiratory Distress Syndrome*

To characterize the endothelial progenitor cell mobilization in the models of moderate and severe lung injury, we hypothesized that there were differences in endothelial progenitor cell levels and mobilizing cytokines between moderate and severe lung injury. Prospective, randomized, and controlled experimental study. University research laboratory center. Fifteen healthy piglets. Piglets were randomly allocated to control, moderate lung injury (acute lung injury), and severe lung injury (acute respiratory distress syndrome) groups. Lung injury was established by intravenous infusion of oleic acid. Animals were mechanically ventilated for 24-48 hours, and then animals were weaned from ventilation and cared for until day 7. Endothelial progenitor cells were quantified by flow cytometry. After 24 hours, the number of endothelial progenitor cells in peripheral blood increased in the acute lung injury group but was not altered in the acute respiratory distress syndrome group compared to the control group. The number of CD34KDR, KDRCD133, and CD34KDRCD133 cells was higher in the acute lung injury group than in the acute respiratory distress syndrome group. In bone marrow, the number of CD34KDR and KDRCD133 cells was greater in acute respiratory distress syndrome animals but not altered in acute lung injury animals at 24 hours. Furthermore, plasma stromal cell-derived factor-1 and vascular endothelial growth factor concentrations were higher in acute lung injury than in acute respiratory distress syndrome at 24 hours. Matrix metalloproteinase-9 and soluble kit ligand levels in bone marrow were reduced in acute respiratory distress syndrome compared with acute lung injury. Lung CD34, KDR, and lung stromal cell-derived factor-1 messenger RNA expression were higher in the acute lung injury group than in the acute respiratory distress syndrome group. Furthermore, the expression of CD34, KDR, and CD133 messenger RNA in lung tissue was correlated with stromal cell-derived factor-1 in the lung. There was a rapid release of endothelial progenitor cells from bone marrow into circulation in moderate acute lung injury, and endothelial progenitor cell mobilization was impaired in acute respiratory distress syndrome.

Hyperbaric oxygen for chronic wounds

Hyperbaric oxygen therapy (HBOT), the administration of pressurized 100% oxygen, is used as an adjunct to aid healing in selected chronic wounds. Though the therapy has had a controversial history, research is now elucidating the mechanisms by which HBOT helps to heal wounds. HBOT increases growth factors and local wound signaling, while also promoting a central stem cell release of endothelial progenitor cells from the bone marrow via nitric oxide pathways. The clinical data continue to accumulate in support of HBOT to help hasten wound healing, and reduce the amputation rate in diabetic ulcers. In appropriate patients, HBOT is an effective, noninvasive, adjunct modality that can be used to hasten chronic wound healing.

Circulating Progenitor and Mature Endothelial Cells in Deep Vein Thrombosis

Introduction: Mature circulating endothelial cells (CEC) and circulating endothelial progenitor cells (EPC) have been described in several conditions associated with endothelial injury. Their role in deep vein thrombosis (DVT) has not been previously evaluated. Patients and Methods: In this pilot study we evaluated the time course of CEC and EPC release after vena cava experimental DVT in mice, using the FeCl3 model. We also evaluated their presence in patients with DVT at different phases of the disease (acute and chronic phase). CEC and EPC were evaluated by Flow Cytometry. Results: In mice, both CEC and EPC were increased 24 hours after DVT induction, peaking 48 hours thereafter. After 72 hours, CEC counts decreased sharply, whereas EPC counts decreased less substantially. In DVT patients we observed a significant increase in CEC counts immediately after DVT compared to healthy individuals. Patients with chronic disease also presented a significant elevation of these cell count. In a subgroup of patients for whom serial samples were available, CEC counts decreased significantly after 9-15 months of the acute event. Conclusions: Our results suggest the participation of these cells in the reparative processes that follows DVT, both at immediate and late time-points. The different kinetics of CEC and EPC release in experimental DVT suggests a heterogeneous role for these cells in the reparative events after DVT.

Endothelial Progenitor Cells Improve Directly and Indirectly Early Vascularization of Mesenchymal Stem Cell-Driven Bone Regeneration in a Critical Bone Defect in Rats

Early vascularization of a composite in a critical bone defect is a prerequisite for ingrowth of osteogenic reparative cells to regenerate bone, since lack of vessels does not ensure a sufficient nutritional support of the bone graft. The innovation of this study was to investigate the direct and indirect effects of endothelial progenitor cells (EPCs) and cotransplanted mesenchymal stem cells (MSCs) on the in vivo neovascularization activity in a critical size defect at the early phase of endochondral ossification. Cultivated human EPCs and MSCs were loaded onto β-TCP in vitro. A critical-sized bone defect (5 mm) was created surgically in the femoral diaphysis of adult athymic rat and stabilized with an external fixateur. The bone defects were filled with β-TCP, MSCs seeded on β-TCP, EPCs seeded on β-TCP, and coculture of MSCs and EPCs seeded on β-TCP or autologous bone of rat. After 1 week, the rats were sacrificed. Using quantitative CD34 immunohistochemistry as well as qualitative analysis of vascularization (staining of MHC and VEGF) in decalcified serial sections were performed by means of an image analysis system. Fluorescence microscopy analyzed the direct effects and indirect effects of human implanted EPCs for vessel formation at bone regeneration site. Formation of a primitive vascular plexus was also detectable in the β-TCP, MSC, or autologous bone group, but on a significantly higher level if EPCs alone or combined with MSCs were transplanted. Moreover, highest amount of vascularization were detected when EPCs and MSCs together were implanted. Early vascularization is improved by transplanted EPCs, which formed new vessels directly. Indeed the indirect effect of EPCs to vascularization is much higher. Transplanted EPC release chemotactic factors (VEGF) to recruit EPCs of the host and stimulate vascularization in the bone defect. Transplantation of human EPCs displays a promising approach to improve early vascularization of a scaffold in a critical bone defect. Moreover, coculture of EPCs and MSCs demonstrate also a synergistic effect on new vessel formation and seems to be a potential osteogenic construct for in vivo application.

Journal-related Activities and Other Special Activities at the 2011 American Society of Anesthesiologists Annual Meeting

Journal-related Activities and Other Special Activities at the 2011 American Society of Anesthesiologists Annual Meeting

BFGF and PDGF-BB have a synergistic effect on the proliferation, migration and VEGF release of endothelial progenitor cells

We have investigated the synergistic effects of bFGF (basic fibroblast growth factor) and PDGF-BB (platelet-derived growth factor-BB) on the proliferation, migration and VEGF (vascular endothelial growth factor) release of EPCs (endothelial progenitor cells). The proliferation of EPCs was assayed by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium]. EPCs migration was detected using the Transwell system. Real-time PCR was used to assess the transcription of PDGFRβ mRNA. PLC-γ (phospholipase C gamma) expression and VEGF release were analysed by Western blot and ELISA. bFGF and PDGF-BB could, respectively, or synergistically, promote the proliferation and migration of EPCs, and these effects of bFGF and PDGF-BB were implemented by enhancing PDGFRβ mRNA, PLC-γ and VEGF expression, while inhibitor of PDGF receptor kinase (AG1296) and the selective PLC inhibitor (U73122) could block these effects of bFGF and PDGF-BB. In the meantime, we proved that the amplification by bFGF and PDGF-BB-stimulated PDGFRβ mRNA, PLC-γ and VEGF expression was abrogated by anti-bFGF antibody, AG1296 and U73122. These results strongly suggest that the proliferation and migration of EPCs may depend on bFGF and/or PDGF-BB by PDGFRβ/PLC-γ signalling pathway, and bFGF and/or PDGF-BB stimulate VEGF release at a point downstream from PDGFRβ/PLC-γ in EPCs.

Engineered alginate hydrogels for effective microfluidic capture and release of endothelial progenitor cells from whole blood.

Microfluidic adhesion-based cell separation systems are of interest in clinical and biological applications where small sample volumes must be processed efficiently and rapidly. While the ability to capture rare cells from complex suspensions such as blood using microfluidic systems has been demonstrated, few methods exist for rapid and nondestructive release of the bound cells. Such detachment is critical for applications in tissue engineering and cell-based therapeutics in contrast with diagnostics wherein immunohistochemical, proteomic, and genomic analyses can be carried out by simply lysing captured cells. This paper demonstrates how the incorporation of four-arm amine-terminated poly(ethylene glycol) (PEG) molecules along with antibodies within alginate hydrogels can enhance the ability of the hydrogels to capture endothelial progenitor cells (EPCs) from whole human blood. The hydrogel coatings are applied conformally onto pillar structures within microfluidic channels and their dissolution with a chelator allows for effective recovery of EPCs following capture.