Subpopulations Of Endothelial Progenitor Cells Research Articles

Association of Plasma Irisin Levels with Circulating Endothelial Microparticles (EMPs) and Endothelial Progenitor Cells (EPCs) in Children Born Prematurely.

Prematurity has been linked with endothelial dysfunction in later life. The purpose of this study was to evaluate the association between plasma irisin, an adipomyokine reported to protect the functional integrity of vascular endothelium, and circulating endothelial microparticles (EMPs) and endothelial progenitor cells (EPCs), consisting early biomarkers of endothelial dysfunction, in preterm-born children. We studied 131 prepubertal children; 61 preterm and 70 born at term (controls). Plasma irisin was determined by ELISA. Circulating CD62E(+), CD144(+) and CD31(+)/CD42b(-) EMPs, and CD34(+)/VEGFR-2(+)/CD45(-) and CD34(+)/VEGFR-2(+)/CD45dim EPCs, were determined by flow cytometry. Body mass index, waist-to-hip ratio, neck circumference, systolic and diastolic blood pressure, and biochemical parameters (glucose, lipids, insulin, HOMA-IR) were also evaluated. Plasma irisin was significantly lower (p = 0.001), whereas circulating EMPs and EPCs were higher, in children born prematurely compared to controls. Irisin was recognized as independent predictor for CD144(+) and CD31(+)/CD42b(-) EMPs, CD34(+)/VEGFR-2(+)/CD45(-) and CD34(+)/VEGFR-2(+)/CD45dim EPCs in the total study population, and for CD31(+)/CD42b(-) EMPs in the preterm group. In conclusion, plasma irisin correlates independently with circulating EMP and EPC subpopulations in prepubertal children and in preterm-born ones. Further studies in children will potentially elucidate the link between irisin and the primary stages of prematurity-related endothelial dysfunction.

Isolating and characterizing lymphatic endothelial progenitor cells for potential therapeutic lymphangiogenic applications

Lymphatic dysfunction is associated with the progression of several vascular disorders, though currently, there are limited strategies to promote new lymphatic vasculature (i.e., lymphangiogenesis) to restore lost lymphatic function. One promising approach to stimulate lymphangiogenesis involves delivering endothelial progenitor cells (EPCs), which are naturally involved in de novo blood vessel formation and have recently been identified to include a lymphatic subpopulation. However, the contribution of lymphatic EPCs in lymphangiogenesis is not clear and challenges with maintaining the activity of transplanted EPCs remain. Thus, the objective of this study was to isolate lymphatic EPCs from human umbilical cord blood and characterize their role in the initial stages of blood or lymphatic vasculature formation. Furthermore, this study also tested the applicability of alginate hydrogels to deliver lymphatic EPCs for a possible therapeutic application. We postulated and confirmed that blood and lymphatic EPC colonies could be isolated from human umbilical cord blood. Additionally, EPC populations responded to either angiogenic or lymphangiogenic growth factors and could stimulate their respective mature endothelial cells in vasculature models in vitro. Finally, lymphatic EPCs maintained their ability to promote lymphatic sprouts after prolonged interactions with the alginate hydrogel microenvironment. These results suggest EPCs have both a blood and a lymphatic population that have specific roles in promoting revascularization and highlight the potential of alginate hydrogels for the delivery of lymphatic EPCs. Statement of significanceDespite the potential therapeutic benefit of promoting lymphatic vasculature, lymphangiogenesis remains understudied. One appealing strategy for promoting lymphangiogenesis involves delivering lymphatic endothelial progenitor cells (EPCs), which are a subpopulation of EPCs involved in de novo vessel formation. Here, we investigate the role of isolated blood and lymphatic EPC subpopulations in promoting the early stages of vascularization and the utility of alginate hydrogels to deliver lymphatic EPCs. We determined that EPCs had two populations that expressed either blood or lymphatic markers, could stimulate their respective mature vasculature in tissue constructs and that alginate hydrogels maintained the therapeutic potential of lymphatic EPCs. We anticipate this work could support promising biomaterial applications of EPCs to promote revascularization, which could have many therapeutic applications.

Proteomic Signature of Dysfunctional Circulating Endothelial Colony-Forming Cells of Young Adults.

BackgroundA subpopulation of endothelial progenitor cells called endothelial colony‐forming cells (ECFCs) may offer a platform for cellular assessment in clinical studies because of their remarkable angiogenic and expansion potentials in vitro. Despite endothelial cell function being influenced by cardiovascular risk factors, no studies have yet provided a comprehensive proteomic profile to distinguish functional (ie, more angiogenic and expansive cells) versus dysfunctional circulating ECFCs of young adults. The aim of this study was to provide a detailed proteomic comparison between functional and dysfunctional ECFCs.Methods and ResultsPeripheral blood ECFCs were isolated from 11 subjects (45% men, aged 27±5 years) using Ficoll density gradient centrifugation. ECFCs expressed endothelial and progenitor surface markers and displayed cobblestone‐patterned morphology with clonal and angiogenic capacities in vitro. ECFCs were deemed dysfunctional if <1 closed tube formed during the in vitro tube formation assay and proliferation rate was <20%. Hierarchical functional clustering revealed distinct ECFC proteomic signatures between functional and dysfunctional ECFCs with changes in cellular mechanisms involved in exocytosis, vesicle transport, extracellular matrix organization, cell metabolism, and apoptosis. Targeted antiangiogenic proteins in dysfunctional ECFCs included SPARC (secreted protein acidic and rich in cysteine), CD36 (cluster of differentiation 36), LUM (lumican), and PTX3 (pentraxin‐related protein PYX3).ConclusionsCirculating ECFCs with impaired angiogenesis and expansion capacities have a distinct proteomic profile and significant phenotype changes compared with highly angiogenic endothelial cells. Impaired angiogenesis in dysfunctional ECFCs may underlie the link between endothelial dysfunction and cardiovascular disease risks in young adults.

CD34+ cells and endothelial progenitor cell subpopulations are associated with cerebral small vessel disease burden.

Background: Endothelial dysfunction is considered to be involved in the pathogenesis of cerebral small vessel disease (CSVD). Endothelial progenitor cellsare associated with endothelial dysfunction. The present study was designed to investigate the correlation between the populations of circulating CD34-positive cells and endothelial progenitor cells and CSVD burden. Methodology &results: A total of364 patients with confirmed diagnosis of CSVD were included in this prospective study. Multiple ordinal logistic regression analyses showed that subjects with higher CSVD burden had significantly decreased circulating CD34+ cell level (odds ratio [OR], 0.42; p = 0.034)and significantly increased levels of circulating CD34+CD133+CD309+ and CD34+CD133+ cells (OR 1.07, p = 0.031; OR 1.03, p = 0.001, respectively), compared with patients with lower CSVD burden. Conclusion: The findings suggest that the levels of circulating CD34+ cells, CD34+CD133+CD309+ cellsand CD34+CD133+ cells may be used as potential biomarkers to monitor the disease progression of CSVD.

Characterization and Functional Assessment of Endothelial Progenitor Cells in Ischemic Stroke Patients.

Endothelial dysfunction has been implicated in atherosclerosis, ischemic heart disease, and stroke. Endothelial progenitor cells (EPCs), found in the bone marrow and peripheral blood as rare cell population, demonstrated a high proliferation and differentiation capacity. Understanding how such diseases influence the quantity and functionality of EPCs is essential for the development of novel therapies. This study aims to investigate the factors that affect the quantity and functionality of circulating EPCs in stroke patients and healthy controls. Blood samples were collected once from healthy donors (n = 30) and up to 3 times (within 7 days (baseline), 3 and 12 months post-stroke) from stroke patients (n = 207). EPC subpopulations were isolated with flow cytometry for characterization. The Matrigel tubular formation assay was performed as a measure of functionality. An increased amount of circulating EPCs was observed in stroke patients over 45 years when compared to age-matched healthy individuals. EPCs showed a rising trend in stroke patients over the 12-month post-stroke period, reaching statistical significance at 12 months post-stroke. Isolated CD34+KDR+ cells from stroke patients showed impairment in tubular formation capability when compared to cells from healthy donors. The quantity and vasculogenic function of circulating EPCs in peripheral blood have been effectively evaluated in stroke patients and healthy control donors in this study. Age and stroke are found to be 2 influencing factors on the angiogenic capacity. It is suggested that the increase in EPC number is triggered by the recovery response following ischemic stroke. Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s12015-020-10064-z.

N-acetylcysteine differentially regulates the populations of bone marrow and circulating endothelial progenitor cells in mice with limb ischemia

Endothelial progenitor cells (EPCs) are important to tissue repair and regeneration especially after ischemic injury, and very heterogeneous in phenotypes and biological features. Reactive oxygen species are involved in regulating EPC number and function. N-acetylcysteine (NAC) inhibits ischemia-induced reactive oxygen species formation and promotes ischemic limb recovery. This study was to evaluate the effect of NAC on EPC subpopulations in bone marrow (BM) and blood in mice with limb ischemia. Limb ischemia was induced by femoral artery ligation in male C57BL/6 mice with or without NAC treatment. EPC subpopulations, intracellular reactive oxygen species production, cell proliferation and apoptosis in BM and blood cells were analyzed at baseline, day 3 (acute ischemia) and 21 (chronic) after ligation. c-Kit+/CD31+, Sca-1+/Flk-1+, CD34+/CD133+, and CD34+/Flk-1+ were used to define EPC subpopulations. Limb blood flow, function, muscle structure, and capillary density were evaluated with laser Doppler perfusion imaging, treadmill test, and immunohistochemistry, respectively, at day 3, 7, 14 and 21 post ischemia. Reactive oxygen species production in circulating and BM mononuclear cells and EPCs populations were significantly increased in BM and blood in mice with acute and chronic ischemia. NAC treatment effectively blocked ischemia-induced reactive oxygen species production in circulating and BM mononuclear cells, and selectively increased EPC population in circulation, not BM, with preserved proliferation in mice with chronic ischemia, and enhanced limb blood flow and function recovery, while preventing acute ischemia-induced increase in BM and circulating EPCs. These data demonstrated that NAC selectively enhanced circulating EPC population in mice with chronic limb ischemia.

Differentiation potential and functional properties of a CD34‑CD133+ subpopulation of endothelial progenitor cells.

Endothelial progenitor cells (EPCs) promote angiogenesis and play an important role in myocardial and vascular repair after ischemia and infarction. EPCs consist of different subpopulations including CD34‑CD133+ EPCs, which are precursors of more mature CD34+CD133+ EPCs and functionally more active in terms of homing and endothelial regeneration. In the present study we analyzed the functional and differentiation abilities of CD34‑CD133+ EPCs. Isolation of EPC populations (CD34+CD133+, CD34‑CD133+) were performed by specific multi‑step magnetic depletion. After specific stimulation a significant higher adhesive and migrative capacity of CD34‑CD133+ cells could be detected compared to CD34+CD133+ cells (P<0.001, respectively). Next to this finding, not only significantly higher rates of proliferation (P<0.005) were detected among CD34‑CD133+ cells, but also a higher potential of cell‑differentiation capacity into other cell types. Next to a significant increase of CD34‑CD133+ EPCs differentiating into a fibroblast cell‑type (P<0.001), an enhancement into a hepatocytic cell‑type (P=0.033) and a neural cell‑type (P=0.016) could be measured in contrast to CD34+CD133+ cells. On the other hand, there was no significant difference in differentiation into a cardiomyocyte cell‑type between these EPC subpopulations (P=0.053). These results demonstrate that EPC subpopulations vary in their functional abilities and, to different degrees, have the capacity to transdifferentiate into unrelated cell‑types such as fibroblasts, hepatocytes, and neurocytes. This indicates that CD34‑CD133+ cells are more pluripotent compared to the CD34+CD133+ EPC subset, which may have important consequences for the therapy of vascular diseases.

Vitamin D improves endothelial barrier integrity and counteracts inflammatory effects on endothelial progenitor cells.

Endothelial colony-forming cells (ECFCs), a proliferative subpopulation of endothelial progenitor cells, are involved in angiogenesis and endothelial repair. In this study, we investigated endothelial barrier characteristics of ECFCs, whether vitamin D supports cell-cell adhesion and barrier integrity, and how it affects ECFC mobilization and actin dynamics. Although ECFC barrier was disrupted under inflammatory conditions, this effect was rescued by vitamin D treatment, leading to higher stability of an ECFC monolayer. Furthermore, vitamin D enhanced ECFC mobilization toward directional migration. In addition, immunocytochemistry, quantitative real-time PCR, and immunoblotting analysis showed that vitamin D increased endothelial interconnections through vascular endothelial cadherin (VE-cadherin) junctions and by impacting cell dynamics through cofilin and VE-cadherin phosphorylation. Our results suggest that vitamin D treatment efficiently counteracts inflammation in an ECFC monolayer, resulting in higher ECFC barrier integrity. This study provides evidence of a new beneficial effect of vitamin D for ECFC homeostasis.-Schröder-Heurich, B., von Hardenberg, S., Brodowski, L., Kipke, B., Meyer, N., Borns, K., von Kaisenberg, C. S., Brinkmann, H., Claus, P., von Versen-Höynck, F. Vitamin D improves endothelial barrier integrity and counteracts inflammatory effects on endothelial progenitor cells.

Concomitant overexpression of triple antioxidant enzymes selectively increases circulating endothelial progenitor cells in mice with limb ischaemia.

Endothelial progenitor cells (EPCs) are a group of heterogeneous cells in bone marrow (BM) and blood. Ischaemia increases reactive oxygen species (ROS) production that regulates EPC number and function. The present study was conducted to determine if ischaemia‐induced ROS differentially regulated individual EPC subpopulations using a mouse model concomitantly overexpressing superoxide dismutase (SOD)1, SOD3 and glutathione peroxidase. Limb ischaemia was induced by femoral artery ligation in male transgenic mice with their wild‐type littermate as control. BM and blood cells were collected for EPCs analysis and mononuclear cell intracellular ROS production, apoptosis and proliferation at baseline, day 3 and day 21 after ischaemia. Cells positive for c‐Kit+/CD31+ or Sca‐1+/Flk‐1+ or CD34+/CD133+ or CD34+/Flk‐1+ were identified as EPCs. ischaemia significantly increased ROS production and cell apoptosis and decreased proliferation of circulating and BM mononuclear cells and increased BM and circulating EPCs levels. Overexpression of triple antioxidant enzymes effectively prevented ischaemia‐induced ROS production with significantly decreased cell apoptosis and preserved proliferation and significantly increased circulating EPCs level without significant changes in BM EPC populations, associated with enhanced recovery of blood flow and function of the ischemic limb. These data suggested that ischaemia‐induced ROS was differentially involved in the regulation of circulating EPC population.

Analysis of endothelial progenitor subpopulation cells, oxidative DNA damage, and their role in coronary artery disease

Background: Endothelial dysfunction has been associated for the cause of atherosclerosis or cardiovascular diseases (CVDs). Endothelial progenitor cells (EPCs) are exposed to oxidative stress during vascular injury as residents of blood vessel walls or as circulating cells homing to the sites of neovascularization. The current study was designed to analyze various subpopulations of EPCs and their DNA damage in CVDs. Methods: The study included 50 coronary artery disease (CAD) patients which was confirmed by angiography and 50 age-matched healthy controls without CAD. Flow cytometric analysis performed to measure subpopulations in EPCs in the peripheral blood using markers such as CD34, CD133, VEGFR2, and CD45. Oxidative DNA damage was analyzed in CD34+ cells. Mean EPC count was expressed as a percentage of total white blood cells. Three different subpopulations with CD45−/CD133+/VEGFR2+, CD45−/CD34+/VEGFR2+, and CD45−/CD34+/CD133+ coexpressions were measured with various percentages. Results: Subpopulation of CD45−/CD34+/VEGFR2+ cells had shown significant (P = 0.001) decrease in CAD patients in comparison with the healthy controls. There was no significant difference in the subpopulations of CD45−/CD34+/CD133+ cells (P = 0.005) and CD45−/CD133+/VEGFR2+ cells (P = 0.005) in CAD and healthy controls. The CD45−/CD34+/VEGFR2+ subpopulation EPC showed positive correlation with the severity of coronary stenosis (r = 0.35, P = 0.026), while other EPC subpopulation count did not show any correlation. Oxidative DNA damage was higher in CAD compared with controls. The number of EPC subpopulation CD45−/CD34+/VEGFR2+ was inversely correlated with oxidative DNA damage (P = 0.001), hypertension (P = 0.001), and diabetes mellitus (P = 0.004). Conclusion: We observed an association between CD45−/CD34+/VEGFR2 subpopulation EPCs and DNA damage in CAD condition. These findings support a cell biologist in searching the role of EPC populations in the pathophysiology or diagnosis of the disease by a clinician.

Preconditioned Endothelial Progenitor Cells as Biomarker of Vascular Reparation?

The endothelial progenitor cells (EPCs) have defined as cells positively labeled with both hematopoietic stem cells (CD34) and endothelial cell markers predominantly VEGF receptor-2 (VEGFR2) cumulatively. Therefore, there are at least two types of EPCs labelled as early outgrowth EPCs and late outgrowth EPCs probably distinguished their vascular protective ability. Recent animal and clinical studies have shown that reduced number and weak function of EPCs may not only indicate to higher CV risk, but contribute to the impaired heart and vessels reparation. Interestingly, there are some subpopulations of EPCs especially recruited from peripheral blood cells, which may exhibit very variable pro-angiogenic effect and endothelial repair capacity and they are called “preconditioned” EPCs. The aim of the short commentary is depicted the possibilities to use of measurement of traditionally labeled EPCs as biomarker of cardiovascular risk.

ARA290, a Specific Agonist of Erythropoietin/CD131 Heteroreceptor, Improves Circulating Endothelial Progenitors' Angiogenic Potential and Homing Ability.

Alternate erythropoietin (EPO)-mediated signaling via the EPOR/CD131 heteromeric receptor exerts the tissue-protective actions of EPO in a wide spectrum of injuries, especially ischemic diseases. Circulating endothelial progenitor cells contribute to endothelial repair and post-natal angiogenesis after chronic ischemic injury. This work aims to investigate the effects of ARA290, a specific agonist of EPOR/CD131 complex, on a subpopulation of endothelial progenitor cells named endothelial colony-forming cells (ECFCs) and to characterize its contribution to ECFCs-induced angiogenesis after peripheral ischemia. ARA290 effects on ECFCs properties were studied using cell cultures in vitro. We injected ARA290 to mice undergoing chronic hindlimb ischemia (CLI) in combination with ECFC transplantation. The homing of transplanted ECFC to ischemic tissue in vivo was assessed by SPECT/CT imaging. In vitro, ARA290 enhanced the proliferation, migration, and resistance to H2O2-induced apoptosis of ECFCs. After ECFC transplantation to mice with CLI, a single ARA290 injection enhanced the ischemic/non-ischemic ratio of hindlimb blood flow and capillary density after 28 days and the homing of radiolabeled transplanted cells to the ischemic leg 4 h after transplantation. Prior neutralization of platelet-endothelial cell adhesion molecule-1 (CD31) expressed by the transplanted cells inhibited ARA290-induced improvement of homing. ARA290 induces specific improvement of the biological activity of ECFCs. ARA290 administration in combination with ECFCs has a synergistic effect on post-ischemic angiogenesis in vivo. This potentiation appears to rely, at least in part, on a CD31-dependent increase in homing of the transplanted cells to the ischemic tissue.

Nectin-2 (CD112) Is Expressed on Outgrowth Endothelial Cells and Regulates Cell Proliferation and Angiogenic Function.

Outgrowth endothelial cells (OECs) are a subpopulation of endothelial progenitor cells (EPCs) that have the capacity for proliferation and the ability to promote angiogenesis. In this study, we identified Nectin-2 as a surface protein of OECs through unbiased quantitative proteomics analysis. Using immunocytochemistry and flow cytometry, we confirmed that Nectin-2 is highly expressed on OECs. Nectin-2 (CD112) expression was limited or lower on mononuclear cells (MNCs) and mature tube-forming endothelial cells (ECs). Blocking Nectin-2 with a neutralizing monoclonal antibody significantly increased the trans-well migration and tube forming capacity of OECs. Similarly, Nectin-2 knockdown resulted in enhanced tube formation, cell migration and proliferation with p-Erk activation. Moreover, Nectin-2 deficiency resulted in compensatory increase of other Nectin family genes including Nectin-3 and Necl-4 which promote VEGFR signaling. These results indicate that Nectin-2 is a surface marker and an important regulator of OECs, with significant implications for the isolation of OECs and blocking Nectin-2 on OECs by an antibody for angiogenic applications.

Neuromuscular electrical stimulation acutely mobilizes endothelial progenitor cells in critically ill patients with sepsis.

BackgroundEndothelial progenitor cells (EPCs) have been suggested to constitute a restoration index of the disturbed endothelium in ICU patients. Neuromuscular electric stimulation (NMES) is increasingly employed in ICU to prevent comorbidities such as ICU-acquired weakness, which is related to endothelial dysfunction. The role of NMES to mobilize EPCs has not been investigated yet. The purpose of this study was to explore the NMES-induced effects on mobilization of EPCs in septic ICU patients.MethodsThirty-two septic mechanically ventilated patients (mean ± SD, age 58 ± 14 years) were randomized to one of the two 30-min NMES protocols of different characteristics: a high-frequency (75 Hz, 6 s on–21 s off) or a medium-frequency (45 Hz, 5 s on–12 s off) protocol both applied at maximally tolerated intensity. Blood was sampled before and immediately after the NMES sessions. Different EPCs subpopulations were quantified by cytometry markers CD34+/CD133+/CD45−, CD34+/CD133+/CD45−/VEGFR2+ and CD34+/CD45−/VEGFR2+.ResultsOverall, CD34+/CD133+/CD45− EPCs increased from 13.5 ± 10.2 to 20.8 ± 16.9 and CD34+/CD133+/CD45−/VEGFR2+ EPCs from 3.8 ± 5.2 to 6.4 ± 8.5 cells/106 enucleated cells (mean ± SD, p < 0.05). CD34+/CD45−/VEGFR2+ EPCs also increased from 16.5 ± 14.5 to 23.8 ± 19.2 cells/106 enucleated cells (mean ± SD, p < 0.05). EPCs mobilization was not affected by NMES protocol and sepsis severity (p > 0.05), while it was related to corticosteroids administration (p < 0.05).ConclusionsNMES acutely mobilized endothelial progenitor cells, measures of the endothelial restoration potential, in septic ICU patients.

Circulating Endothelial Progenitor Cells in Youth: Fitness, Physical Activity and Adiposity.

Circulating endothelial progenitor cells (EPCs) are early markers of cardiovascular impairment. The role of EPCs in youth remains unclear, and is complicated by differences in how cells are identified. This study (1) described EPCs in pre- and late-pubertal males and females, (2) examined their association with fitness, activity and adiposity, and (3) compared EPCs to published cell definitions. 94 participants completed 2 sessions. During the first session, aerobic fitness (Wpeak) and moderate-to-vigorous physical activity (MVPA) were assessed. During the second session, percent body fat (%BF) was determined by DXA, and a fasted blood sample was collected to measure EPCs by flow cytometry. EPCs were identified as CD31(+)CD34(bright)CD45(dim)CD133(+). Samples were reanalyzed and cell counts were compared to 8 previously published EPC definitions. EPCs were similar in pre- and late-pubertal males and females (p>0.05). Neither EPC concentrations nor proportions were correlated with Wpeak (ρ=- 0.04 to-0.06), MVPA (ρ=- 0.09 to - 0.07) or %BF (ρ=0.20 to 0.14). Agreement between cell data analyzed according the different cell definitions ranged from Κ=-0.06 to 0.82. Our findings suggest that EPCs were not associated with fitness, MVPA or adiposity in youth. The overall poor agreement across definitions may be indicative of distinct EPC subpopulations.

Relation between endothelial progenitor cells and arterial stiffness in patients with psoriasis.

Patients with psoriasis are prone to premature atherosclerosis. We hypothesize that depletion of circulating endothelial progenitor cells (EPC) is related to patients with psoriasis and can contribute to the development of atherosclerosis. Thirty-five plaque-type psoriasis patients (41.9 ± 5.5 years, 30 men) and 20 age- and sex-matched controls were studied. Four subpopulations of EPC, namely, CD34(+) EPC, CD133(+) EPC, CD34(+) /kinase insert domain-containing receptor (KDR)(+) EPC and CD133(+) /KDR(+) EPC were measured by flow cytometry. Arterial stiffness in psoriasis patients was assessed by heart to ankle pulse wave velocity (haPWV), augmentation index (AI) and carotid intima media thickness (IMT). Patients with psoriasis had a lower level of CD34(+) EPC (7.85 ± 2.49% vs 6.26 ± 2.13%, P = 0.02) compared with healthy controls. In patients with psoriasis, level of CD34(+) EPC was negatively related with haPWV (r = -0.43 P = 0.01) and Psoriasis Area and Severity Index (r = -0.39 P = 0.02). Multivariate regression analysis further demonstrated that haPWV was independently associated with level of CD34(+) EPC. Each percentage decrease in CD34(+) EPC accounted for an increase in haPWV of +0.02 m/s. The result demonstrated that patients with psoriasis had reduced CD34(+) EPC compared with controls. Importantly, CD34(+) EPC was independently related with haPWV in these patients. This finding suggests that EPC reduction is associated with the development of arterial stiffness in patients with psoriasis.

Endothelial progenitor cells as markers of severity in hypertrophic cardiomyopathy.

Endothelial progenitor cells (EPCs) are bone marrow-derived cells that are mobilized into the circulation to migrate and differentiate into mature endothelial cells contributing to post-natal physiological and pathological neovascularization. In this study, we evaluated circulating EPCs in patients with hypertrophic cardiomyopathy (HCM) and examined a potential association with clinical parameters of the disease. We included 40 HCM patients and 23 healthy individuals. Using flow cytometry we measured EPCs in peripheral blood as two subpopulations of CD45-/CD34+/VEGFR2+ and CD45-/CD34+/CD133+ cells. Circulating CD45-/CD34+/VEGFR2+ cells were significantly increased in HCM patients in comparison with the controls (0.000238 ± 0.0003136 vs. 0.000057 ± 0.0001316, respectively, P = 0.002). However, there was no significant difference in the number of circulating CD45-/CD34+/CD133+ cells (0.003079 ± 0.0033288 vs. 0.002065 ± 0.0022173, respectively, P = 0.153). The CD45-/CD34+/VEGFR2+ subpopulation revealed a moderate correlation with LV mass index (r = 0.35, P = 0.026), while both EPC subpopulation levels showed strong positive correlations with th E/e' ratio (r = 0.423, P = 0.007 for CD45-/CD34+/VEGFR2+ and r = 0.572, P < 0.001 for CD45-/CD34+/CD133+). HCM patients showed an increased mobilization of EPCs compared with healthy individuals that correlated with diastolic dysfunction. Our findings may open up new dimensions in the pathophysiology, prognostication, and treatment of HCM.

Reduced endothelial progenitor cells in extracranial arterial stenosis but not intracranial arterial stenosis

Endothelial progenitor cells (EPCs) are novel markers of endothelial dysfunction and are related to cardiovascular disease. However, their relationship with cerebral atherosclerosis (CA) has not been investigated extensively. We aim to study the relationship between CA severity and EPC subpopulations levels. We enrolled 197 patients in this study. EPCs were measured by flow cytometry. Digital subtraction angiography was used to assess CA. Arterial lesion severity was evaluated among cerebral arteries which showed steno-occlusion change and the extent of that condition. There was a significant inverse correlation between EPCs level and CA prevalence after adjusting for confounders (CD45(-/dim)CD34(+)CD309(+) cells: odds ratio [OR], 0.110; 95% confidence interval [CI], 0.026-0.475; P = .00; CD45(-/dim)CD133(+)CD309(+) cells: OR, 0.134; 95% CI, 0.030-0.599; P = .01; CD45(-/dim) CD34(+)CD133(+)CD309(+) cells: OR, 0.010; 95% CI, 0.001-0 .541, P = .02). Multivariate logistic regression analysis showed that only the EPCs level was significantly inversely associated with extracranial atherosclerosis rather than intracranial atherosclerosis (P > .05). Our data indicated that EPCs subpopulations were independent predictors for CA severity, even after controlling for traditional risk factors.

Diverse contribution of bone marrow-derived late-outgrowth endothelial progenitor cells to vascular repair under pulmonary arterial hypertension and arterial neointimal formation

AimsIt is still controversial whether bone marrow (BM)-derived endothelial progenitor cells (EPCs) can contribute to vascular repair and prevent the progression of vascular diseases. We aimed to characterize BM-derived EPC subpopulations and to evaluate their therapeutic efficacies to repair injured vascular endothelium of systemic and pulmonary arteries. Methods and resultsBM mononuclear cells of Fisher-344 rats were cultured under endothelial cell-conditions. Early EPCs appeared on days 3–6. Late-outgrowth and very late-outgrowth EPCs (LOCs and VLOCs) were defined as cells forming cobblestone colonies on days 9–14 and 17–21, respectively. Among EPC subpopulations, LOCs showed the highest angiogenic capability with enhanced proliferation potential and secretion of proangiogenic proteins. To investigate the therapeutic effects of these EPCs, Fisher-344 rats underwent wire-mediated endovascular injury in femoral artery (FA) and were concurrently injected intraperitoneally with 60mg/kg monocrotaline (MCT). Injured rats were then treated with six injections of one of three EPCs (1×106 per time). After 4weeks, transplanted LOCs, but not early EPCs or VLOCs, significantly attenuated neointimal lesion formation in injured FAs. Some of CD31+ LOCs directly replaced the injured FA endothelium (replacement ratio: 11.7±7.0%). In contrast, any EPC treatment could neither replace MCT-injured endothelium of pulmonary arterioles nor prevent the progression of pulmonary arterial hypertension (PAH). LOCs modified protectively the expression profile of angiogenic and inflammatory genes in injured FAs, but not in MCT-injured lungs. ConclusionBM-derived LOCs can contribute to vascular repair of injured systemic artery; however, even they cannot rescue injured pulmonary vasculature under MCT-induced PAH.

Thrombin receptor PAR-1 activation on endothelial progenitor cells enhances chemotaxis-associated genes expression and leukocyte recruitment by a COX-2-dependent mechanism.

Endothelial colony forming cells (ECFC) represent a subpopulation of endothelial progenitor cells involved in endothelial repair. The activation of procoagulant mechanisms associated with the vascular wall's inflammatory responses to injury plays a crucial role in the induction and progression of atherosclerosis. However, little is known about ECFC proinflammatory potential. To explore the role of the thrombin receptor PAR-1 proinflammatory effects on ECFC chemotaxis/recruitment capacity. The expression of 30 genes known to be associated with inflammation and chemotaxis was quantified in ECFC by real-time qPCR. PAR-1 activation with the SFLLRN peptide (PAR-1-ap) resulted in a significant increase in nine chemotaxis-associated genes expression, including CCL2 and CCL3 whose receptors are present on ECFC. Furthermore, COX-2 expression was found to be dramatically up-regulated consequently to PAR-1 activation. COX-2 silencing with the specific COX-2-siRNA also triggered down-regulation of the nine target genes. Conditioned media (c.m.) from control-siRNA- and COX-2-siRNA-transfected ECFC, stimulated or not with PAR-1-ap, were produced and tested on ECFC capacity to recruit leukocytes in vitro as well in the muscle of ischemic hindlimb in a preclinical model. The capacity of the c.m. from ECFC stimulated with PAR-1-ap to recruit leukocytes was abrogated when COX-2 gene expression was silenced in vitro (in terms of U937 cells migration and adhesion to endothelial cells) as well as in vivo. Finally, the postnatal vasculogenic stem cell derived from infantile hemangioma tumor (HemSC) incubated with PAR-1-ap increased leukocyte recruitment in Matrigel(®) implant. PAR-1 activation in ECFC increases chemotactic gene expression and leukocyte recruitment at ischemic sites through a COX-2-dependent mechanism.