The mobilization of CD34 positive mononuclear cells after myocardial infarction is abolished by revascularization of the culprit vessel

[Factors influencing mobilisation of endothelial progenitor cells and angiogenic cytokines after an extensive acute myocardial infarction]

BACKGROUND AND OBJECTIVES

Following an acute myocardial infarction (AMI), bone-marrow derived endothelial progenitor cells (EPC) are mobilised into the peripheral blood. Our aim was to examine the factors influencing this spontaneous cell mobilisation.

PATIENTS AND METHODS

In this study we analysed 47 patients with extensive AMI (left ventricular ejection fraction [LVEF] <50% by echocardiography during the first week post-AMI); we studied the peripheral blood EPC populations expressing CD133(+), CD34(+), KDR(+), CXCR4(+), as well as the cytokines VEGF (vascular endothelial growth factor), SDF-1 (stromal cell-derived factor 1) and TSP-1 (thrombospondin 1), measured on day 5±2.5 after AMI.

RESULTS

The extension of AMI (CPK peak) correlated with the number of CD133(+) mobilised cells: (r=0.40; P=.011). Patients who did not receive perfusion during the acute phase (34%) had more CD34(+)CXCR4(+) cells with a median (interquartile ranges) of 2,401 (498-7,004) vs. 999 (100-1,600), P=.048, and strong correlations between VEGF and CD133(+)CD34(+)KDR(+) (r=.84; P<.01) and SDF-1 and CD34(+)CXCR4(+) (r=.67; P<.01), and between these 2 cytokines (r=.57; P=.01). In the reperfused patients, the correlation between VEGF and CD133(+)CD34(+)KDR(+) was lower (r=.38; P=.03) and the correlation between SDF-1 and CD34(+)CXCR4(+) and VEGF disappeared. Multivariate analysis showed that a VEGF >7pg/mL (P<.01) predicted the mobilisation of CD133(+)CD34(+)KDR(+), whereas hypertension showed a trend (P=.055). Diabetes (P=.045) predicted the number of CD34(+)CXCR4(+), with reperfusion treatment showing a trend in this subpopulation (P=.054).

CONCLUSIONS

Mobilisation of progenitor cells after AMI is influenced by factors such as diabetes and the cytokine VEGF. Hypertension and reperfusion therapy during the acute phase also tend to influence the cell response.

Hyperaldosteronism is associated with a decrease in number and altered growth factor expression of endothelial progenitor cells in rats

BACKGROUND

Aldosterone plays a role in hypertension, the pathogenesis of heart failure and vascular injury. However, little information exists about the possible influence of aldosterone on bone marrow derived endothelial progenitor cells (EPC), which are involved in the repair of damaged endothelium. This study was designed to determine the long- term in vivo influence of aldosterone on the number of EPC.

METHODS

Male Wistar rats were equipped with a subcutaneous pump which released aldosterone (n=20) or placebo (n=20) over 28 days. The animals were either fed with or without the aldosterone antagonist spironolactone (each n=10). EPC were identified by the uptake of ac-LDL and BS-1. The expression of VEGF-2 receptor, VEGF, HGF, SDF1 and the mineralocorticoid receptor (MR) in EPC was assessed by quantitative PCR. Finally, VEGF concentration was measured in the serum of all animals by ELISA.

RESULTS

The total number of EPC was significantly lowered by chronic aldosterone treatment. Spironolactone compensated the effect and lead to a 2-fold increase. While the SDF1 mRNA was not affected by aldosterone, HGF, MR2 and VEGF receptor mRNA were significantly downregulated in EPC. Strikingly spironolactone not only leads to increases in the mRNA expression in hyper-aldosteronemic animals but also exhibited significant increases above the control levels.

CONCLUSION

The present data indicate that high levels of aldosterone impair the function and reduce the numbers of EPC and lead to a downregulation of VEGF and the VEGF receptor in vivo. Spironolactone antagonized these effects. MR blockade by spironolactone may therefore represent a future tool to enhance the response to cell based therapy.

From bone marrow to the arterial wall: the ongoing tale of endothelial progenitor cells

Several physiological and pathophysiological stimuli or drugs modulate endothelial progenitor cell (EPC) mobilization. Moreover, levels of circulating EPCs predict cardiovascular risk and left ventricular remodelling after myocardial infarction. Nevertheless, our understanding in this field is complicated by lack of an unequivocal definition of EPCs, thus limiting their clinical applications. This review summarizes current knowledge and uncertainties on EPC characterization and mobilization in the attempt to define their role in the management of cardiovascular diseases.

Decreased number of circulating progenitor cells in obesity: beneficial effects of weight reduction

AIMS

Cardiovascular risk factors are associated with decreased levels of circulating progenitor cells (CPC). The aim of this study was to determine whether the number of CPC is an independent correlate of body mass index (BMI) and whether weight loss leads to an increase in CPC.

METHODS AND RESULTS

CD34 positive and KDR/CD34, CD133/CD34, and CD117/CD34 double positive cells were measured by fluorescence activated cell sorting (FACS) analysis in peripheral blood of 149 volunteers (52.5 +/- 12.0 years, BMI 21.5-52.7 kg/m(2), mean 31.6 +/- 5.1 kg/m(2)) participating in a weight reduction program offered by German pharmacies. In addition, carotid intima media thickness (IMT) and brachial artery flow-mediated dilatation were determined. After a diet and sports program for 6 months, 86 representing subjects were re-evaluated (mean weight loss 5.8 +/- 5.2 kg). There was an inverse correlation between BMI as well as waist circumference and CPC, especially CD34 positive, KDR/CD34 positive, CD133/CD34 positive, and CD117/CD34 positive cells. This decrease in CPC in obesity held true not only for the absolute cell numbers, but also for the relative fractions of KDR, CD133, and CD117 positive cells within the CD34 positive cells, indicating a specific down regulation of these progenitor cell types. Multiple regression analysis revealed that BMI was a more prominent predictor of CPC regulation than blood pressure, LDL cholesterol, triglycerides, fasting glucose, and smoking. IMT increased in dependence on BMI (P < 0.001) and was inversely correlated with the number of CD34 positive cell (P < 0.05). After diet, there was a significant increase of CD34 and CD117/CD34 positive cells, which correlated with the decrease in BMI. Also, weight loss was accompanied by a decrease in IMT (P = 0.015), which also correlated with the increase in CPC (P < 0.001). The increase in the number of CPC was independent from whether weight loss was achieved by increased physical exercise or by reduced calorie intake only.

CONCLUSION

Obesity is associated with decreased numbers of CPC and increased IMT. Diet and weight loss lead to an increase in CPC count, which might contribute to regression of IMT.

Factors influencing spontaneous mobilization of CD34+ and CD133+ progenitor cells after myocardial infarction

BACKGROUND

Bone marrow-derived circulating progenitor cells (BM-CPCs) are mobilized into adult peripheral blood (PB) during acute myocardial infarction (AMI) and may contribute to the regeneration of infarcted myocardium. The purpose of the present study is to determine whether mobilization of BM-CPCs into PB depends on cardiovascular risk factors (CVRFs), age of patients, infarct associated inflammatory markers, and left ventricular function after AMI.

MATERIALS AND METHODS

Peripheral blood concentrations of CD34/45(+) and CD133/45(+) BM-CPCs were measured by flow cytometry in 44 patients after AMI and in 16 subjects with atypical chest pain acting as controls.

RESULTS

Mobilization of CD34/45(+) and CD133/45(+) BM-CPCs on day 1 after AMI showed significant negative correlation with age, the number of CVRFs, infarct size, creatine phosphokinase peak in bivariate as well as in multivariate analyses. We additionally found a positive correlation of CD34/45(+) and CD133/45(+) BM-CPCs mobilization on day 1 after AMI with global ejection fraction (EF) in bivariate analysis but could not confirm this in multivariate analysis. Elevated of C-reactive protein (CRP) and leukocyte levels on day 1 after AMI were significantly associated with decreased concentrations of CD34/45(+) BM-CPCs. The concentrations of CD34/45(+) and CD133/45(+) BM-CPCs significantly increased in AMI patients, with the peak on day 7 as compared to the control group.

CONCLUSIONS

The mobilization of CD34/45(+) and CD133/45(+) BM-CPCs into the PB depends on many factors, i.e. the number of CVRFs, age, infarct size and inflammatory markers of patients. Most importantly, the severity of the circulatory dysfunction and the amount of necrotic myocardial tissue are the main determinants. Moreover, this spontaneous mobilization of BM-CPCs may serve as a very important surrogate for infarct size as well as for global EF and it may determine the regenerative potency after AMI.

Differential increase of CD34, KDR/CD34, CD133/CD34 and CD117/CD34 positive cells in peripheral blood of patients with acute myocardial infarction

OBJECTIVE

Circulating progenitor cells (CPC) may contribute to cardiac regeneration and neovascularization after acute myocardial infarction (AMI). For potential therapeutic use, understanding the endogenous mechanisms after ischemia is inevitable. We investigated the absolute number, but also the subset composition of CD34+ CPC after AMI.

METHODS

CD34+, KDR+/CD34+, CD133+/CD34+ and CD117+/CD34+CPC were analyzed by FACS in peripheral blood of 10 patients with acute MI (59+/-5 yrs, m/f=8/2) at day of AMI (day 0) and days 1-5. For comparison patients with stable coronary artery disease (CAD, n=12, 66+/-2 yrs, m/f=10/2) and young healthy volunteers (n=7, 26+/-2 yrs, m/f=3/4) were studied.

RESULTS

CD34 and KDR/CD34, CD133/CD34, CD117/CD34 were increased day 3 and 4 after AMI. KDR+ fraction within CD34+ population remained unchanged (58.3+/-7.8% vs 55.3+/-10.6%), whereas CD133+ (64.9+/-3.1% vs 43.5+/-5.9%, P=0.006) and CD117+ fractions (71.7+/-5.6% vs 50.1+/-5.5%, P=0.02) were elevated. In CAD, all CPC and fractions were similar as AMI day 0. Healthy volunteers had more CD34+ than CAD and AMI day 0. Double positive CPC were also higher, but fractions were unchanged vs CAD with more KDR/CD34 in trend (72.8+/-10.6% vs 50.5+/-5.6%, P=0.058). After AMI both absolute numbers of CD34+ and their subset composition change, suggesting selective mobilization of CPC. Increased CPC after AMI never reach numbers of young healthy volunteers.

Cell Therapy in Kidney Disease: Cautious Optimism … But Optimism Nonetheless

The recently discovered therapeutic potential of stem or progenitor cells has initiated development of novel treatments in a number of diseases—treatments that could not only improve patients’ quality of life, but also halt or even prevent disease progression. Hypertension; fluctuations in glycemia, electrolytes, nutrient levels, and circulating volume; and frequent infections and the associated inflammation all greatly impair the endothelium in patients undergoing peritoneal dialysis. As our understanding of the regulatory function of the endothelium advances, focus is increasingly being placed on endothelial repair in acute and chronic renal failure and after renal transplantation. The potential of progenitor cells to repair damaged endothelium and to reduce inflammation in patients with renal failure remains unexamined; however, a successful cell therapy could reduce morbidity and mortality in kidney disease.

Important contributions have been made in identifying progenitor cell populations in the kidney, and further investigations into the relationships of these cells with the pathophysiology of the disease are underway. As the kidney disease field prepares for the first human trials of progenitor cell therapies, we deemed it important to review representative original research, and to share our perspectives and lessons learned from clinical trials of progenitor cell–based therapies that have commenced in patients with cardiovascular disease.