VEGF increases engraftment of bone marrow-derived endothelial progenitor cells (EPCs) into vasculature of newborn murine recipients

Recent evidence suggests that bone marrow-derived angioblasts or endothelial progenitor cells circulate in peripheral blood and can incorporate at sites of pathologic neovascularization or during the ovarian cycle. However, the incorporation of endothelial progenitor cells into vessels of nonischemic tissues in adult animals has not been observed. We hypothesized that the vascular microenvironment differs between newborn and adult animals, and that donor endothelial cell progenitors would engraft in rapidly growing normal tissues during the neonatal period. After nonablative administration of bone marrow cells either at birth or at 4 weeks of age, donor-derived endothelial cells were found only in the neovasculature of the newborn recipients. Both the incorporation of donor endothelial cells into the newborn neovasculature as well as tissue vascularity were significantly increased by coadministering vascular endothelial growth factor with bone marrow cells. These findings suggest that bone marrow-derived endothelial progenitor cells can contribute to neovascularization during the newborn period and are responsive to vascular endothelial growth factor.     

Circulating endothelial and endothelial progenitor cells in patients with severe sepsis

Elevated circulating endothelial cell (CEC) and circulating endothelial progenitor cell (CEPC) counts may indicate vascular damage and disease status, but data on these cell populations in patients with severe sepsis are limited. This study compared CEC and CEPC counts in patients with and without severe sepsis following intensive care unit (ICU) admission. Venous blood samples were collected within 24 h, 48-72 h, and 120-144 h. Baseline demographics, 28-day mortality, ICU and hospital days, and Sequential Organ Failure Assessment (SOFA) scores were recorded. Patients with (n = 18) and without (n = 28) severe sepsis were balanced for mean age (63.7 and 61.3 years, respectively) and gender. There were no differences in 28-day mortality, ICU days, or hospital days. Baseline SOFA scores were higher in the sepsis group. At 48-72 h, patients with severe sepsis had significantly higher median CEC counts (51.5 vs. 28.0 cells/4 ml of blood, P = 0.02). CEC values for all ICU patients were significantly (P < 0.05) higher than in healthy volunteers. CEPC counts in both cohorts ranged from 0 to > 21 colonies/4 ml blood (mean = 1.13 ± 2.25; median = 0) without significant differences at any time point. This study demonstrates the ability to quantify CECs and CEPCs using consensus methodology. Understanding the relationship between CEC/CEPC counts and outcomes may provide insight into the mechanisms of endothelial cell changes in severe sepsis.     

Effect of smoking cessation on the number and adhesive properties of early outgrowth endothelial progenitor cells

Background

Endothelial progenitor cells participate in angiogenesis and vascular repair, and cardiovascular risk factors may reduce their numbers or impair their functional properties. Cigarette smoking is a leading cause of preventable cardiovascular death, however, the functional properties of these cells before and after discontinuation of tobacco use have not been systematically analyzed.

Methods

We examined changes in the number and function of early outgrowth endothelial progenitor cells (EPC), isolated from individuals (n = 144; mean age, 47.8 ± 12.0 years; 43% males; more than 50% with additional cardiovascular risk factors or disease) who successfully completed a 5-week smoking cessation (SC) programme.

Results

SC significantly reduced total white blood cell count (WBC; P < 0.0001), plasma LDL cholesterol (P = 0.0002) and fibrinogen (P < 0.0001) levels, but did not alter the number of circulating CD34⁺, VEGFR2⁺ or CD34⁺, CD133⁺ cells (P = 0.14 and 0.57, respectively). Fewer acLDL⁺, lectin⁺ cells could be expanded from peripheral blood mononuclear cells in comparison to baseline (P < 0.001). Furthermore, SC was associated with reduced EPC adhesion to fibronectin (P < 0.001) or TNFα-activated endothelial cells (P = 0.003), and a diminished incorporation of EPC into endothelial cell networks (P = 0.035). Mechanistically, significantly reduced β1- and β2-integrin expression (P < 0.001 and 0.007) and lower contents of intracellular reactive oxygen species (P < 0.007) were detected in EPC following SC, in addition to reduced plasma asymmetric dimethyl-L-arginine (ADMA) levels (P = 0.0003).

Conclusions

Our findings suggest that the oxidative and inflammatory stress reduction associated with smoking cessation impair the adhesiveness of monocyte-derived EPC.     

老年急性白血病患者内皮祖细胞的变化及其临床意义

目的探讨老年急性白血病(AL)患者骨髓及外周血中内皮祖细胞(EPCs)的数量变化及其临床意义。方法采用流式细胞仪(FCM)检测66例初治AL患者骨髓及外周血中的EPCs,其中老年AL组28例,非老年AL组38例。以10例良性血液病患者为对照组。结果 (1)老年AL患者骨髓EPCs绝对计数较外周血明显增高(P<0.001),相对计数较外周血无明显差异(P>0.05)。(2)老年AL患者、非老年AL患者骨髓及外周血EPCs水平较对照组明显增高(P<0.01)。老年AL组骨髓及外周血中EPCs水平较非老年AL组降低,两者无统计学差异(P>0.05)。(3)老年AL患者外周血EPCs绝对计数与白细胞计数(r=0.815,P=0.027)、β2-微球蛋白(r1=0.709,P=0.043)、LDH(r2=0.827,P=0.026)呈正相关。结论老年AL患者EPCs水平明显增高,EPCs可能与老年AL发病相关。     

Circulating endothelial progenitor cells are reduced in SLE in the absence of coronary artery calcification

Circulating endothelial progenitor cells (EPCs) are reduced in patients with systemic lupus erythematosus (SLE). A reduced number of EPCs are associated with the presence of atherosclerosis in other populations. We sought to determine whether the reduction in EPC numbers in SLE is dependent on the presence of advanced coronary artery calcification (CAC). Patients with SLE had previous coronary calcium scores which placed them in either the >75th percentile or <25th percentile for their age. Seventeen patients with SLE and 13 healthy controls (HC) were included in the study. White blood cells were stained for EPC and progenitor cell markers including CD34, CD133, and VEGFR and analyzed by flow cytometry. SLE patients had repeated coronary imaging as well as carotid ultrasound. There was no difference in age between groups. SLE patients with advanced CAC were more likely to be hypertensive, to be smokers, and to have longer disease duration than SLE patients without CAC. SLE patients without evidence of CAC had a significantly lower number of EPCs (CD34+/CD133+/VEGFR+) compared to HC (median (IQR)) 0 (0, 6.7) vs. 10.2 (5.8, 12.3) (P = 0.02). Total numbers of PCs (CD133+/CD34+) were not significantly decreased in patients with SLE ((mean ± SEM) 1,007 ± 154 vs. 824 ± 170 (P = 0.20)). No significant difference was seen in EPC number between SLE patients without CAC and those with advanced CAC. Increased carotid intima-media thickness did not correlate with CAC or EPC number in SLE patients. Reduced numbers of EPCs in SLE patients may be observed compared to HC even in the absence of CAC. Differences in measured risk factor profiles and depletion of total circulating PCs do not fully explain this finding.     

Dynamics of endothelial progenitor cells in patients with advanced hepatocellular carcinoma

Background and aimsCirculating endothelial progenitor cells (EPC) predict tumor vascularization and disease progression, but limited information is available on their dynamics in hepatocellular carcinoma (HCC) undergoing systemic treatment.MethodsWe prospectively analyzed different populations of EPC in 16 patients with advanced HCC receiving sorafenib. Patients were studied before therapy (T0, n = 16) and after two (T2, n = 12) and eight weeks (T8, n = 8), using high-performance flow-cytometry. The tumor response at T8 was categorized as progressive disease (PD) or clinical benefit (CB, all other responses).ResultsAt T0, higher levels of CD34⁺CD133⁺KDR⁺ and CD34⁺KDR⁺ were observed in patients with alpha-fetoprotein ≥400 ng/ml or non-viral liver disease, whereas CD34⁺CD133⁺KDR⁺ cells were virtually absent in patients with vascular invasion. CD34⁺KDR⁺ and CD34⁺CD133⁺KDR⁺ were directly correlated with platelet count. Frequencies of all populations of EPC declined in patients receiving sorafenib. Levels of CD34⁺CD133⁺ were higher at T0 in patients with CB compared to patients with PD. In patients belonging to the CB group CD34⁺KDR⁺ cells at T0 were directly correlated to platelet count.ConclusionIn patients with advanced HCC, EPC are directly correlated with platelet count, suggesting a common activation of selected bone marrow pathways. Levels of a CD34⁺KDR⁺ are higher at baseline in patients responding to sorafenib.     

Decrease and senescence of endothelial progenitor cells in patients with preeclampsia

BACKGROUND: In preeclampsia, the precise mechanism of impaired vascular function is still unclear. We hypothesized that cellular function of circulating endothelial progenitor cells (EPCs) might be impaired in patients with preeclampsia. OBJECTIVE: The objective of this study was to investigate the number and status of cellular senescence of EPCs in the circulation of women with preeclampsia. METHODS: Circulating EPCs were cultured from patients with preeclampsia (n = 8) and normotensive pregnant women (n = 7). EPC numbers were assessed by colony-forming unit (CFU) methodology as previously reported. In addition, to assess cellular senescence, we measured endogenous beta-galactosidase activity. Moreover, we assessed whether the serum level of C-reactive protein (CRP), a marker for systemic inflammation, was associated with cellular impairment of EPCs. RESULTS: The number of circulating EPCs was decreased in women with preeclampsia controls (median, 10.0 vs. 34.0 CFU; P < 0.01). The rate of cellular senescence was significantly increased in patients with preeclampsia (33.9%) compared with that in controls (22.9%; P < 0.05). Patients with preeclampsia were divided into two subgroups: the CRP-negative group (CRP, <0.1 mg/dl; n = 4) and the CRP-positive group (CRP, > or =0.1 mg/dl; n = 4). Interestingly, EPC CFU counts were markedly decreased in CRP-positive patients compared with those in CRP-negative patients (5.0 and 25.0 CFU, respectively; P < 0.05). Median values for cellular senescence were greater in the CRP-positive group than in the CRP-negative group, although this did not achieve statistical significance (43.5% and 33.3%, respectively; P = 0.12). CONCLUSION: Depletion and cellular aging of EPCs in patients with preeclampsia might be associated with endothelial dysfunction and could be affected by systemic inflammation.     

不稳定性心绞痛患者循环内皮祖细胞与血管内皮功能的变化

目的探讨不稳定性心绞痛患者外周血循环内皮祖细胞(EPCS)与血管内皮功能的变化。方法采用高分辨率血管超声法检测30例不稳定性心绞痛患者与30例正常者作对照组肱动脉血流介导的内皮依赖性血管舒张功能(FMD)及硝酸甘油介导的非内皮依赖性血管舒张功能(NMD);流式细胞仪测定外周血中CD34+单个核细胞的水平;外周血分离单个核细胞一定条件下培养2周,免疫组织化学技术鉴定培养贴壁细胞表面标志CD34的表达;倒置荧光显微镜鉴定贴壁细胞FITC-UEA-I和DII-ACLDL双染色阳性细胞为正在分化的EPCS。结果不稳定性心绞痛组FMD明显低于对照组[(5·85±3·04)%比(8·81±4·48)%,P<0·05];NMD在两组中差异无统计学意义[(13·60±5·03)%比(14·18±4·50)%,P>0·05];CD34+细胞水平明显高于对照组[(0·13±0·05)%比(0·09±0·04)%,P<0·05];FMD与CD34+细胞水平呈负相关(R=-0·385,P<0·05)。培养的贴壁细胞免疫组化显示CD34阳性,倒置荧光显微镜显示这些贴壁细胞FITC-UEA-I和DII-ACLDL双染色阳性。结论不稳定性心绞痛患者CD34+细胞增加和血管内皮功能受损,提示循环EPCS增加可能是对急性冠状动脉缺血和内皮损伤的代偿反应。     

Plerixafor stimulates adhesive activity and endothelial regeneration of endothelial progenitor cells via elevating CXCR7 expression

AimsTo assess the effects of plerixafor on function and endothelial regeneration of endothelial progenitor cells (EPCs).MethodsThe proliferation and adhesion capacity of EPCs were evaluated in vitro. Furthermore, the expression levels of CXC chemokine receptor-7 (CXCR7) were detected before and after treatment with plerixafor. The CXCR7 expression of EPCs was knocked-down by RNA interference to evaluate the role of CXCR7 in regulating function of EPCs. A rat carotid artery injury model was established to assess the influences of plerixafor on endothelial regeneration.ResultsPlerixafor stimulated adhesion capacity of EPCs, associating with upregulation of CXCR7 and activation of LFA-1 and VLA-4 molecules. Knockdown of CXCR7 slightly impaired proliferation capacity but significantly attenuated adhesion capacity of EPCs. Plerixafor facilitated endothelial repair at 7 days, while reduced neointimal hyperplasia at 7 and 14 days via recruiting more EPCs participating in endothelial reparation.ConclusionsPlerixafor can positively regulate adhesion capacity of EPCs to HUVECs via elevating the expression level of CXCR7 and stimulating LFA-1 and VLA-4 molecules activation. Treatment with plerixafor accelerated re-endothelialization and inhibited neointimal hyperplasia after endoth elial injury, indicating that it can to be used for endothelial regeneration.     

Lacidipine improves endothelial repair capacity of endothelial progenitor cells from patients with essential hypertension

Background

Endothelial progenitor cells (EPCs) play a critical role in maintaining the integrity of vascular endothelium following arterial injury. Lacidipine has a beneficial effect on endothelium of hypertensive patients, but limited data are available on EPCs-mediated endothelial protection. This study tests the hypothesis that lacidipine treatment can improve endothelial repair capacity of EPCs from hypertensive patients through increasing CXC chemokine receptor four (CXCR4) signaling.

Methods

In vivo reendothelialization capacity of EPCs from hypertensive patients with or without in vitro lacidipine treatment was examined in a nude mouse model of carotid artery injury. Expression of CXCR4 and alteration in migration and adhesion functions of EPCs were evaluated.

Results

Basal CXCR4 expression was markedly reduced in EPCs from hypertensive patients compared with normal subjects. In parallel, the phosphorylation of Janus kinase-2 (JAK-2) of EPCs, a CXCR4 downstream signaling, was also significantly decreased. Lacidipine promoted CXCR4/JAK-2 signaling expression of in vitro EPCs. Transplantation of EPCs pretreated with lacidipine significantly accelerated in vivo reendothelialization. The enhanced in vitro function and in vivo reendothelialization capacity of EPCs were inhibited by shRNA-mediated knockdown of CXCR4 expression or pretreatment with JAK-2 inhibitor AG490, respectively. In hypertensive patients, lacidipine treatment for 4 weeks also resulted in an upregulation of CXCR4/JAK-2 signaling of EPCs, which was associated with augmented EPCs-mediated reendothelialization and improved endothelial function.

Conclusion

Deterioration of CXCR4 signaling may lead to impaired EPCs-mediated reendothelialization of hypertensive patients. Lacidipine-modified EPCs via a partially CXCR4 signaling contribute to enhanced endothelial repair capacity in hypertension.     

Decreased supportive function of platelets from patients with SLE on human endothelial cells

Platelets show a supportive effect on human endothelial cells in culture. Platelets of patients with systemic lupus erythematosus showed a significantly reduced growth stimulation as demonstrated by reduced DNA synthesis of the endothelial cells.