Circulating progenitor cells and their interaction with platelets in patients with an acute coronary syndrome

CD34⁺ cells expressing KDR (CD34⁺/KDR⁺) represent a small proportion of circulating progenitor cells that have the capacity to interact with platelets and to differentiate into mature endothelial cells, thus contributing to vascular homeostasis and regeneration as well as to re-endothelialization. We investigated the levels of CD34⁺ and CD34⁺/KDR⁺ progenitor cells as well as their interaction with platelets in acute coronary syndrome (ACS) patients before the initiation (baseline) of their treatment with a P2Y₁₂ receptor antagonist, and at 5-days post-treatment (follow-up). Sixty-seven consecutive ACS patients and thirty healthy subjects (controls) participated in the study. On admission, all patients received 325 mg aspirin, followed by 100 mg/day and then were loaded either with 600 mg clopidogrel or 180 mg ticagrelor, followed by 75 mg/day (n = 36) or 90 mg × 2/day (n = 31), respectively. The levels of circulating CD34⁺ and CD34⁺/KDR⁺ progenitor cells, as well as their interaction with platelets, were determined by flow cytometry, before and after activation with ADP, in vitro. The circulating levels of CD34⁺ and CD34⁺/KDR⁺ cells in both patient groups at baseline were lower compared with controls while they were significantly increased at 5-days of follow-up in both groups, this increase being more pronounced in the ticagrelor group. The platelet/CD34⁺ (CD61⁺/CD34⁺) conjugates were higher at baseline and reduced at follow-up while the platelet/KDR⁺ (CD61⁺/KDR⁺) conjugates were lower at baseline and increased at follow-up, both changes being more pronounced in the ticagrelor group. ADP activation of control samples significantly increased the KDR expression by CD34⁺ cells and the CD61⁺/KDR⁺ conjugates, these parameters being unaffected in patients at baseline but increased at follow-up. Short-term dual antiplatelet therapy in ACS patients restores the low platelet/KDR⁺ conjugates and CD34⁺ cell levels and improves the low membrane expression levels of KDR in these cells, an effect being more pronounced in ticagrelor-treated patients. This may represent a pleiotropic effect of antiplatelet therapy towards vascular endothelial regeneration.     

Endothelial progenitor cells correlate with endothelial function in patients with coronary artery disease

Endothelial progenitor cells (EPC) predict morbidity and mortality in patients at cardiovascular risk.Patients with low EPC counts and impaired endothelial colony forming activity have a higher incidence for cardiovascular events compared to patients with high EPC counts and favorable colony forming activity. The pathophysiological basis for this finding may be an insufficient endothelial cell repair by EPC.We postulate that EPC influence coronary endothelial function which itself is relevant for the outcome of patients at cardiovascular risk. To test this hypothesis in humans, endothelial function was invasively assessed in 90 patients with coronary heart disease by quantitative coronary angiography during intracoronary acetylcholine infusion. Flow cytometry of mononuclear cells isolated from peripheral blood was performed to assess CD133(+) or CD34(+)/KDR(+) EPC. EPC function was assessed ex vivo by determination of endothelial colony forming units. Low EPC number as well as impaired endothelial colony forming activity correlated with severely impaired coronary endothelial function in univariate analysis. Multivariate analysis revealed that only the number of EPC predicts severe endothelial dysfunction independent of classical cardiovascular risk factors. Endothelial function closely correlates with the number of circulating EPC providing new mechanistic insights and options for risk assessment in patients with coronary heart disease.     

内皮祖细胞在急性肺损伤中的应用

急性肺损伤(acute lung injury,ALI)是临床常见危重症,目前缺乏有效的治疗手段,病死率高达40%[1].内皮细胞的损伤和活化在ALI发病机制中占有极其重要的地位[2].     

药物洗脱支架对老年急性冠状动脉综合征患者内皮祖细胞的影响

目的探讨急性冠状动脉综合征患者行药物洗脱支架置入后,对内皮祖细胞(EPC)数量及功能的影响。方法选择急性冠状动脉综合征患者60例,根据治疗分为支架置入组32例和单纯药物组28例,均在入院时、术后1周及6个月采用流式细胞仪测定外周血中CD34/KDR单个核细胞水平;外周血分离单个核细胞体外诱导培养2周,异硫氰酸荧光素标记荆豆凝集素Ⅰ和DiI标记乙酰化低密度脂蛋白免疫荧光染色双阳性细胞为正在分化的EPC,分别观察其集落形成、增殖及迁移能力。结果与术前比较,支架置入组术后1周及6个月EPC数量、双阳性细胞数量、迁移及增殖能力明显增高(P<0.05);与单纯药物组比较,支架置入组术后1周及6个月EPC数量、双阳性细胞数量、迁移及增殖能力明显增高(P<0.05)。结论药物洗脱支架置入后EPC数量及功能均增加,从而有助于改善动脉血管内皮功能。     

Endothelial progenitor cells in patients with essential hypertension

OBJECTIVE(S): The eventual role of blood pressure on the endothelial progenitor cell (EPC) has rarely been evaluated and data collected so far relate to patients with co-existing coronary heart disease. METHODS: We have studied the number and functional activity of EPC as well as the number of EPC endothelial colony-forming units (CFU) in a carefully selected group of 36 patients with essential hypertension and 24 normotensive control subjects. RESULTS: In patients with essential hypertension, the EPC number was not statistically different from that found in control subjects (mean +/- SD, essential hypertension 58 +/- 29, controls 53 +/- 20; EPC/high power field). CFU per well were not statistically different in patients with essential hypertension compared with normotensive controls (mean +/- SD, patients with essential hypertension 2.4 +/- 2.6, normotensive controls 3 +/- 3.3 CFU/well). In essential hypertension patients, the EPC number was inversely correlated with both total (R=0.635, P < 0.0001) and low-density lipoprotein (LDL)-cholesterol (R=0.486, P < 0.05). Neither the EPC number nor the EPC CFU were correlated with age, systolic blood pressure, diastolic blood pressure, body mass index, lipoprotein(a), high-sensitivity C-reactive protein or homocysteine. CONCLUSIONS: The present study shows that essential hypertension is not characterized by the altered number or functional activity of EPC. Plasma total and LDL-cholesterol are independent predictors of reduced numbers of circulating EPC in essential hypertension patients. The absence of any correlation between the characteristics of EPC and several markers predictive of cardiovascular damage merits further investigation.     

Endothelial progenitor cells are reduced in refractory hypertension

Circulating endothelial progenitor cells (EPCs) play a key role in the maintenance of endothelial homoeostasis and promote vascular repair. They may also be of predictive value for cardiovascular events. Reduced EPC number and functional activity have been associated with several cardiovascular risk factors, but their relationship with hypertension remains unclear. The objective of this study was to investigate if number and function of circulating EPCs are reduced in patients with refractory hypertension (RHT). Circulating EPCs (CD34+ CD133+/CD45+) were isolated from peripheral blood by flow cytometry in 39 RHT and 30 normotensive controls. EPC number was also determined in vitro after 7 days in culture. After age adjustment, EPC concentration was significantly reduced in RHT as compared with controls (mean (95% CI), 33.8 (18.1-49.6) vs 69.1 (50.7-87.5) EPCs per 10(5) peripheral mononuclear cells (MNCs), respectively; P=0.014). After in vitro culture, EPCs were also reduced in patients as compared with controls (mean (95% CI), 142.3 (49.5-235.0) vs 611.0 (480.2-741.8) EPCs per field, respectively, P<0.001). In multiple linear regression analysis, circulating EPCs were significantly reduced by 56.3% in RHT as compared with control (P=0.006), independently of all other known risk factors. Moreover, RHT had a high independent predictive value for lower EPC proliferation. The number of EPCs per field was reduced by 76.7% in RHT with respect to controls (P<0.001). In summary, the number of circulating EPCs after culture is reduced in patients with RHT, which may be related to the increased rate of endothelial dysfunction, atherosclerotic disease and cardiovascular events observed in this population.     

Endothelial progenitor cells and coronary artery disease

Endothelial progenitor cells have radically altered the way in which vascular biologists and clinicians think about the genesis, development, and healing of atherosclerotic lesions.     

急性冠脉综合征患者内皮祖细胞及C反应蛋白的变化

目的:观察急性冠脉综合征(ACS)患者外周血中内皮祖细胞(EPCs)及C反应蛋白的变化。方法:入选40例ACS(不稳定型心绞痛18例、急性心肌梗死22例)患者与20例行冠状动脉造影术排除冠心病的正常人(正常对照组),取所有研究对象外周血100μl分别加入CD34-PE、AC133-异硫氰酸荧光素(FITC)荧光抗体使与EPCs表面CD34、AC133抗原结合,通过流式细胞仪检测PE、FITC阳性细胞的数量。同时检测高敏C反应蛋白(hsCRP)浓度。结果:与正常对照组比较,不稳定型心绞痛、急性心肌梗死患者外周血中EPCs数量显著增多[(0.48±0.04)%比(0.84±0.31)%比(1.57±0.62)%,P<0.001],hsCRP浓度明显升高[(0.63±011)mg/L比(7.8±0.59)mg/L比(11.2±0.46)mg/L,P<0.001],且上述指标在急性心肌梗死组明显高于不稳定心绞痛组(P<0.001),所有患者外周血中EPCs数量与hsCRP浓度正相关(r=0.82,P<0.001)。结论:急性冠脉综合征患者外周血中内皮祖细胞数量显著增多,可能与炎症因子激活骨髓干细胞分化为内皮祖细胞,参与血管修复有关。     

老年急性冠状动脉综合征患者辅助性T淋巴细胞的研究

目的 通过分析老年急性冠状动脉综合征(ACS)患者外周血中辅助性T淋巴细胞亚群1(Th1)和亚群2(Th2)频率的变化,探讨辅助性T淋巴细胞在ACS进程中的作用.方法 通过细胞内细胞染色对32例ACS患者(ACS组)、35例稳定性心绞痛(SAP)患者(SAP组)及20例健康体检者(对照组)的外周血单个核细胞进行Th1、Th2分型,ELISA法检测血浆Th1、Th2相关细胞因子水平:干扰素-γ(IFN-γ)、白细胞介素2(IL-2)、白细胞介素4(IL-4)和白细胞介素10(IL-10).结果 ACS组患者Th1细胞较SAP组及对照组明显升高(P＜0.05);3组间Th2细胞变化无统计学差异(P＞0.05).ACS组患者Th1相关细胞因子IFN-γ和IL-2较SAP组和对照组明显升高(P＜0.05);ACS组患者Th2相关细胞因子IL-10较SAP组和对照组明显降低(P＜0.05),IL-4低于检测水平;IFN-γ和IL-2水平与Th1的升高密切相关(P＜0.05).结论 Th1和Th2的失衡与ACS的发生密切相关,其相关细胞因子IFN-γ和IL-2水平的升高,使系统炎性反应进一步恶化.     

老年急性冠状动脉综合征患者树突状细胞的功能状态

目的　研究老年急性冠状动脉综合征 (ACS)患者树突状细胞 (DC)的功能。方法　将 4 5例ACS患者分为老年组 (2 5例 )和非老年组 (2 0例 ) ,另选健康体检者 2 2例分为老年对照组 (12例 )和非老年对照组 (10例 ) ,入院时取外周血分离单个核细胞 ,制备DC。检测DC表面共刺激分子CD86的表达和DC对同种异体T淋巴细胞的刺激能力 ;酶联免疫吸附法测定培养液中细胞因子浓度 ;分析CD86表达相关因素。结果　与非老年组比较 ,老年组DC功能下降。与老年和非老年对照组比较 ,ACS患者DC表面CD86的表达明显增高 ;对T淋巴细胞刺激的能力增强 ;经DC刺激的淋巴细胞分泌致炎细胞因子增多 ,抑炎细胞因子减少 ;CD86的表达与血清低密度脂蛋白及C反应蛋白水平呈正相关。ACS时DC的激活与年龄无关。结论　正常人DC功能随年龄增加而下降 ;老年ACS患者DC的功能亢进可能是ACS发病及预后不良的原因 ;低密度脂蛋白与DC的激活有关。     

Impact of a cardiac rehabilitation program and inflammatory state on endothelial progenitor cells in acute coronary syndrome patients

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), VO₂ 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 VO₂ 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.     

Endothelial adhesion molecules ICAM-1, VCAM-1 and E-selectin in patients with acute coronary syndrome

INTRODUCTION AND OBJECTIVES: The acute inflammatory response is an important phenomenon in the pathogenesis of myocardial damage during acute coronary syndrome. Endothelial dysfunction has been found in unstable angina and acute myocardial infarction, although the results are controversial. The purpose of this study was to determine the levels of the soluble endothelial adhesion molecules ICAM-1, VCAM-1 and E-selectin, in patients with unstable angina and acute myocardial infarction, compare the results in both groups, and analyze their relation with the degree of myocardial injury. METHODS: Serum concentrations of ICAM-1, VCAM-1, and E-selectin were measured in 37 control subjects and 43 patients (32 with acute myocardial infarction and 11 with unstable angina). Measurements were made at the time of admission and ten days later using commercial enzyme-linked immunoabsorbent assay (ELISA) kits (R&D Systems, UK). RESULTS: There was a significant increase in E-selectin (p < 0.05) in patients with unstable angina at admission and ten days later. In contrast, patients with acute myocardial infarction showed no significant differences in E-selectin compared with the control group at admission or ten days later. A significant increase in VCAM-1 levels was demonstrated in both groups of patients and ICAM-1 levels in acute myocardial infarction, but the concentrations of VCAM-1 and ICAM-1 in both groups of patients at admission and ten days later did not differ significantly. There was no relation between soluble endothelial adhesion molecule levels and the severity of myocardial damage estimated by cardiac enzymes or electrocardiographic changes. CONCLUSION: This study indicates that serum levels of E-selectin, measured at time of admission and ten days later, could be a marker for unstable angina and might be useful in the differential diagnosis with myocardial infarction.