Endothelial dysfunction is one of the earliest pathological effects of cigarette smoking. It has recently been suggested that endothelial progenitor cells (EPCs) could contribute to ongoing endothelial maintenance and repair. Accordingly, we tested the hypothesis that cigarette smoking is associated with EPC dysfunction.
EPCs were isolated from the peripheral venous blood of 15 healthy smokers and 11 age-matched nonsmokers. The number of EPCs was significantly reduced in smokers versus control subjects (51.6+/-1.9 versus 120.3+/-10.0 per power field, p<0.001). Moreover, the functional activities of EPCs isolated from smokers were severely compromised. First, the proliferative and migratory response of EPCs isolated from smokers were reduced by 75% and 19%, respectively (p<0.05). Second, EPCs from smokers showed an important decreased adherence to HUVECs that had been previously activated with tumor necrosis factor-alpha (TNF-alpha) (p<0.01). Finally, the participation of EPCs to tube formation in a matrigel assay was reduced by 38% in smokers versus control subjects (p<0.001). We found that EPCs from smokers had a significant reduction in the expression of the endothelial cell-specific markers (VE-cadherin, KDR, and vWF). Moreover, ROS formation was significantly increased in EPCs from smokers, whereas the serum antioxidant and nitrite levels of smokers were reduced and correlated with impaired EPC number and functional activity.
Cigarette smoking is associated with a reduced number of EPCs together with an important impairment of EPC differentiation and functional activities. Our results suggest that EPC dysfunction could contribute to impair blood vessel healing and growth in smokers.
"These findings were bolstered by our significant decrements in bone marrow EPC function, specifically chemotaxis and tube formation, which rely on these chemical signals. Michaud and colleagues also found that exposure to smoke caused a reduction in the chemotaxis potential and tube formation of EPCs (Michaud et al., 2006). The loss of EPC function is particularly concerning given their reparative role in the cardiovascular system. "
[Show abstract][Hide abstract] ABSTRACT: Introduction:
The discovery of endothelial progenitor cells (EPCs) may help to explain observed cardiovascular effects associated with inhaled nickel nanoparticle exposures, such as increases in vascular inflammation, generation of reactive oxygen species, altered vasomotor tone and potentiated atherosclerosis in murine species.
Following an acute whole body inhalation exposure to 500 µg/m(3) of nickel nanoparticles for 5 h, bone marrow EPCs from C57BL/6 mice were isolated. EPCs were harvested for their RNA or used in a variety of assays including chemotaxis, tube formation and proliferation. Gene expression was assessed for important receptors involved in EPC mobilization and homing using RT-PCR methods. EPCs, circulating endothelial progenitor cells (CEPCs), circulating endothelial cells (CECs) and endothelial microparticles (EMPs) were quantified on a BD FACSCalibur to examine endothelial damage and repair associated with the exposure.
Results and conclusions:
Acute exposure to inhaled nickel nanoparticles significantly increased both bone marrow EPCs as well as their levels in circulation (CEPCs). CECs were significantly elevated indicating that endothelial damage occurred due to the exposure. There was no significant difference in EMPs between the two groups. Tube formation and chemotaxis, but not proliferation, of bone marrow EPCs was impaired in the nickel nanoparticle exposed group. These results coincided with a decrease in the mRNA of receptors involved in EPC mobilization and homing. These data provide new insight into how an acute nickel nanoparticle exposure to half of the current Occupational Safety & Health Administration (OSHA) permissible exposure limit may adversely affect EPCs and exacerbate cardiovascular disease states.
"Circulating endothelial progenitor cells (EPCs) are mobilized from the bone marrow and are able to integrate into vascular structures at sites of neovascularisation where they differentiate into endothelial cells and proliferate , . Many studies suggest that the physiological function of EPCs is the maintenance of vascular integrity –. Cord blood EPC-derived endothelial cells (EPDCs) isolated from human umbilical cord blood can be extensively expanded in vitro. "
[Show abstract][Hide abstract] ABSTRACT: The vascular system is adapted to specific functions in different tissues and organs. Vascular endothelial cells are important elements of this adaptation, leading to the concept of 'specialized endothelial cells'. The phenotype of these cells is highly dependent on their specific microenvironment and when isolated and cultured, they lose their specific features after few passages, making models using such cells poorly predictive and irreproducible. We propose a new source of specialized endothelial cells based on cord blood circulating endothelial progenitors (EPCs). As prototype examples, we evaluated the capacity of EPCs to acquire properties characteristic of cerebral microvascular endothelial cells (blood-brain barrier (BBB)) or of arterial endothelial cells, in specific inducing culture conditions.
First, we demonstrated that EPC-derived endothelial cells (EPDCs) co-cultured with astrocytes acquired several BBB phenotypic characteristics, such as restricted paracellular diffusion of hydrophilic solutes and the expression of tight junction proteins. Second, we observed that culture of the same EPDCs in a high concentration of VEGF resulted, through activation of Notch signaling, in an increase of expression of most arterial endothelial markers.
We have thus demonstrated that in vitro culture of early passage human cord blood EPDCs under specific conditions can induce phenotypic changes towards BBB or arterial phenotypes, indicating that these EPDCs maintain enough plasticity to acquire characteristics of a variety of specialized phenotypes. We propose that this property of EPDCs might be exploited for producing specialized endothelial cells in culture to be used for drug testing and predictive in vitro assays.
PLoS ONE 01/2014; 9(1):e84179. DOI:10.1371/journal.pone.0084179 · 3.23 Impact Factor
"This group of patients showed significantly lower exercise capacity, significantly higher levels of hsCRP and a higher prevalence , albeit not significant, of smoking habit and hypertension. Both these risk factors have been previously associated with a depletion of circulating EPCs, through decreased mobilization from the bone marrow and increased senescence   . Therefore it is conceivable that all these factors could have influenced the different response of these patients to the PA protocol. "
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Among the benefits of a cardiac rehabilitation (CR) program for patients after an acute coronary syndrome (ACS) is the mobilization of endothelial progenitor cells (EPCs). However not all patients respond to CR with an increase of EPC. We performed this study to identify the characteristics of patients who will not benefit from an increase of EPCs at the end of a CR program. METHODS: 112 ACS patients were admitted to a four-week CR program. EPCs, high sensitivity C-reactive protein (hsCRP) and NT-ProBNP levels were determined at the beginning (T1) and at the end (T2) of the CR program. All patients performed a cardiopulmonary exercise test at T1 and at T2. EPCs were defined as CD34+KDR+, CD133+KDR+ and CD34+CD133+KDR+. hsCRP and NT-ProBNP were measured by nephelometric and immunometric method, respectively. RESULTS: At T2, we observed a significant increase of EPCs (p=0.001), VO(2) peak, Watt max HDL-cholesterol (p<0.0001) and a significant decrease (p<0.001) of hsCRP and NT-ProBNP, triglycerides, HbA1c, systolic blood pressure and waist circumference. Variations of VO(2) peak were significantly correlated with the variations of EPCs. Patients with increased EPCs showed significantly (p=0.01) lower baseline levels of CRP and higher basal Watt max (p=0.04). In a multivariate logistic regression analysis, the lowest tertile of baseline hsCRP significantly affected the likelihood of having an increase of EPCs at the end of the CR program. CONCLUSIONS: A CR program determines an increase of EPCs with a decrease of CRP and NT-ProBNP. A different trend for EPCs can be detected among patients correlated to CRP levels and exercise tolerance.
International journal of cardiology 05/2012; 167(5). DOI:10.1016/j.ijcard.2012.04.157 · 4.04 Impact Factor
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