Amaryllis H. Van Craenenbroeck

Quantification of circulating CD34+/KDR+/CD45dim endothelial progenitor cells: analytical considerations.

The discovery of peripheral circulating cells that contribute to vasculogenesis and endothelial repair was one of the most fascinating breakthroughs in the domain of vascular research during the last two decades. The population of vasculogenic cells however, is heterogeneous and can be analyzed using different approaches including in vitro culture and flow cytometry. Circulating CD34(+)/KDR(+)/CD45(dim) endothelial progenitor cells (EPC) have a great potential as biomarkers in various cardiovascular diseases. With the expanding interest in this field, the development of standardized protocols is critical. In this review we describe in detail the pre-analytical and analytical factors that should be taken into account when quantifying CD34(+)/KDR(+)/CD45(dim) EPC using flow cytometry. Moreover, technical suggestions in order to enhance accuracy and reproducibility of this enumeration are provided.

Assessment of Endothelial Dysfunction in Childhood Obesity and Clinical Use

The association of obesity with noncommunicable diseases, such as cardiovascular complications and diabetes, is considered a major threat to the management of health care worldwide. Epidemiological findings show that childhood obesity is rapidly rising in Western society, as well as in developing countries. This pandemic is not without consequences and can affect the risk of future cardiovascular disease in these children. Childhood obesity is associated with endothelial dysfunction, the first yet still reversible step towards atherosclerosis. Advanced research techniques have added further insight on how childhood obesity and associated comorbidities lead to endothelial dysfunction. Techniques used to measure endothelial function were further brought to perfection, and novel biomarkers, including endothelial progenitor cells, were discovered. The aim of this paper is to provide a critical overview on both in vivo as well as in vitro markers for endothelial integrity. Additionally, an in-depth description of the mechanisms that disrupt the delicate balance between endothelial damage and repair will be given. Finally, the effects of lifestyle interventions and pharmacotherapy on endothelial dysfunction will be reviewed.

Effect of Moderate Aerobic Exercise Training on Endothelial Function and Arterial Stiffness in CKD Stages 3-4: A Randomized Controlled Trial

BACKGROUND Evidence of a beneficial effect of exercise training on mediators of vascular disease is accumulating in chronic kidney disease (CKD), but its effect on vascular function in vivo still has to be established. The present study was designed to investigate whether a formal aerobic exercise training program improves peripheral endothelial function in patients with CKD stages 3 to 4. STUDY DESIGN Randomized controlled trial with a parallel-group design. SETTING & PARTICIPANTS 48 patients with CKD stages 3 to 4 without established cardiovascular disease were randomly assigned to either an exercise training program or usual care. 40 patients completed the study (exercise training, 19; usual care, 21). INTERVENTION The 3-month home-based aerobic training program consisted of 4 daily cycling sessions of 10 minutes each at a target heart rate, calculated as 90% of the heart rate achieved at the anaerobic threshold. Patients in the usual-care group were given standard therapy. OUTCOMES The primary outcome was peripheral endothelial function. Secondary outcomes were aerobic capacity, arterial stiffness, numbers of endothelial (EPCs) and osteogenic progenitor cells (OPCs), migratory function of circulatory angiogenic cells, and health-related quality of life. MEASUREMENTS Endothelial function was assessed with flow-mediated dilation of the brachial artery, aerobic capacity by peak oxygen uptake (VO(2peak)), arterial stiffness by carotid-femoral pulse wave velocity, numbers of EPCs and OPCs by flow cytometry, circulatory angiogenic cell function by an in vitro migratory assay, and quality of life by the Kidney Disease Quality of Life-Short Form questionnaire. RESULTS Exercise training significantly improved VO(2peak) and quality of life, but not in vivo vascular function (flow-mediated dilation and carotid-femoral pulse wave velocity) or cellular markers for vascular function (EPC and OPC count and circulatory angiogenic cell migratory function). LIMITATIONS Short duration and intermittent nature of the exercise intervention. CONCLUSIONS In patients with CKD stages 3 to 4 without overt cardiovascular disease, 3 months of aerobic exercise training improved VO(2peak) and quality of life, without altering endothelial function or arterial stiffness.

Plasma levels of microRNA in chronic kidney disease: patterns in acute and chronic exercise

Exercise training is an effective way to improve exercise capacity in chronic kidney disease (CKD), but the underlying mechanisms are only partly understood. In healthy subjects (HS), microRNA (miRNA or miR) are dynamically regulated following exercise and have, therefore, been suggested as regulators of cardiovascular adaptation to exercise. However, these effects were not studied in CKD before. The effect of acute exercise (i.e., an acute exercise bout) was assessed in 32 patients with CKD and 12 age- and sex-matched HS (study 1). miRNA expression in response to chronic exercise (i.e., a 3-mo exercise training program) was evaluated in 40 CKD patients (study 2). In a subgroup of study 2, the acute-exercise induced effect was evaluated at baseline and at follow-up. Plasma levels of a preselected panel miRNA, involved in exercise adaptation processes such as angiogenesis (miR-126, miR-210), inflammation (miR-21, miR-146a), hypoxia/ischemia (miR-21, miR-210), and progenitor cells (miR-150), were quantified by RT-PCR. Additionally, seven miRNA involved in similar biological processes were quantified in the subgroup of study 2. Baseline, studied miRNA were comparable in CKD and HS. Following acute exercise, miR-150 levels increased in both CKD (fold change 2.12 ± 0.39, P = 0.002; and HS: fold change 2.41 ± 0.48 P = 0.018, P for interaction > 0.05). miR-146a acutely decreased in CKD (fold change 0.92 ± 0.13, P = 0.024), whereas it remained unchanged in HS. Levels of miR-21, miR-126, and miR-210 remained unaltered. Chronic exercise did not elicit a significant change in the studied miRNA levels. However, an acute exercise-induced decrease in miR-210 was observed in CKD patients, only after training (fold change 0.76 ± 0.15). The differential expression in circulating miRNA in response to acute and chronic exercise may point toward a physiological role in cardiovascular adaptation to exercise, also in CKD.

Vascular Effects of Exercise Training in CKD: Current Evidence and Pathophysiological Mechanisms

Cardiovascular disease remains the main cause of morbidity and mortality in patients with CKD, an observation that cannot be explained by the coexistence of traditional risk factors alone. Recently, other mechanisms, such as alterations in nitric oxide bioavailability, impaired endothelial repair mechanisms, inflammation, and oxidative stress (all characteristic in CKD), have gained much attention as mediators for the increased cardiovascular risk. Regular physical training is a valuable nonpharmacological intervention for primary and secondary prevention of cardiovascular disease. Likewise, the benefits of exercise training on exercise capacity and quality of life are increasingly recognized in patients with CKD. Furthermore, exercise training could also influence potential reversible mechanisms involved in atherosclerosis and arteriosclerosis. After discussing briefly the general concepts of vascular disease in CKD, this review provides an overview of the current evidence for the effects of exercise training at both clinical and preclinical levels. It concludes with some practical considerations on exercise training in this specific patient group.

Acute Exercise-Induced Response of Monocyte Subtypes in Chronic Heart and Renal Failure

Purpose. Monocytes (Mon1-2-3) play a substantial role in low-grade inflammation associated with high cardiovascular morbidity and mortality of patients with chronic kidney disease (CKD) and chronic heart failure (CHF). The effect of an acute exercise bout on monocyte subsets in the setting of systemic inflammation is currently unknown. This study aims (1) to evaluate baseline distribution of monocyte subsets in CHF and CKD versus healthy subjects (HS) and (2) to evaluate the effect of an acute exercise bout. Exercise-induced IL-6 and MCP-1 release are related to the Mon1-2-3 response. Methods. Twenty CHF patients, 20 CKD patients, and 15 HS were included. Before and after a maximal cardiopulmonary exercise test, monocyte subsets were quantified by flow cytometry: CD14++CD16−CCR2+ (Mon1), CD14++CD16+CCR2+ (Mon2), and CD14+CD16++CCR2− (Mon3). Serum levels of IL-6 and MCP-1 were determined by ELISA. Results. Baseline distribution of Mon1-2-3 was comparable between the 3 groups. Following acute exercise, %Mon2 and %Mon3 increased significantly at the expense of a decrease in %Mon1 in HS and in CKD. This response was significantly attenuated in CHF (P < 0.05). In HS only, MCP-1 levels increased following exercise; IL-6 levels were unchanged. Circulatory power was a strong and independent predictor of the changes in Mon1 (β = −0.461, P < 0.001) and Mon3 (β = 0.449, P < 0.001); and baseline LVEF of the change in Mon2 (β = 0.441, P < 0.001). Conclusion. The response of monocytes to acute exercise is characterized by an increase in proangiogenic and proinflammatory Mon2 and Mon3 at the expense of phagocytic Mon1. This exercise-induced monocyte subset response is mainly driven by hemodynamic changes and not by preexistent low-grade inflammation.

Induction of Cytomegalovirus-Specific T Cell Responses in Healthy Volunteers and Allogeneic Stem Cell Recipients Using Vaccination With Messenger RNA–Transfected Dendritic Cells

Background Infection with human cytomegalovirus (CMV) is a significant cause of morbidity and mortality in solid organ and hematopoietic stem cell transplant (HSCT) recipients. Methods The present study explored the safety, feasibility, and immunogenicity of CMV pp65 messenger RNA–loaded autologous monocyte-derived dendritic cells (DC) as a cellular vaccine for active immunization in healthy volunteers and allogeneic HSCT recipients. Four CMV-seronegative healthy volunteers and three allogeneic HSCT recipients were included in the study. Four clinical-grade autologous monocyte-derived DC vaccines were prepared after a single leukapheresis procedure and administered intradermally at a weekly interval. Results De novo induction of CMV-specific T-cell responses was detected in three of four healthy volunteers without serious adverse events. Of the HSCT recipients, none developed CMV disease and one of two patients displayed a remarkable threefold increase in CMV pp65-specific T cells on completion of the DC vaccination trial. Conclusion In conclusion, our DC vaccination strategy induced or expanded a CMV-specific cellular response in four of six efficacy-evaluable study subjects, providing a base for its further exploration in larger cohorts.

Effects of aerobic interval training and continuous training on cellular markers of endothelial integrity in coronary artery disease: a SAINTEX-CAD substudy

In this large multicenter trial, we aimed to assess the effect of aerobic exercise training in stable coronary artery disease (CAD) patients on cellular markers of endothelial integrity and to examine their relation with improvement of endothelial function. Two-hundred CAD patients (left ventricular ejection fraction > 40%, 90% male, mean age 58.4 ± 9.1 yr) were randomized on a 1:1 base to a supervised 12-wk rehabilitation program of either aerobic interval training or aerobic continuous training on a bicycle. At baseline and after 12 wk, numbers of circulating CD34(+)/KDR(+)/CD45dim endothelial progenitor cells (EPCs), CD31(+)/CD3(+)/CXCR4(+) angiogenic T cells, and CD31(+)/CD42b(-) endothelial microparticles (EMPs) were analyzed by flow cytometry. Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery. After 12 wk of aerobic interval training or aerobic continuous training, numbers of circulating EPCs, angiogenic T cells, and EMPs were comparable with baseline levels. Whereas improvement in peak oxygen consumption was correlated to improvement in FMD (Pearson r = 0.17, P = 0.035), a direct correlation of baseline or posttraining EPCs, angiogenic T cells, and EMP levels with FMD was absent. Baseline EMPs related inversely to the magnitude of the increases in peak oxygen consumption (Spearman rho = -0.245, P = 0.027) and FMD (Spearman rho = -0.374, P = 0.001) following exercise training. In conclusion, endothelial function improvement in response to exercise training in patients with CAD did not relate to altered levels of EPCs and angiogenic T cells and/or a diminished shedding of EMPs into the circulation. EMP flow cytometry may be predictive of the increase in aerobic capacity and endothelial function.

Hallervorden-Spatz disease : historical case presentation in the spotlight of nosological evolution

Baron Dr. Ludo van Bogaert (1897–1989) authored more than 700 publications, gave countless lectures at Belgian and foreign universities and at international congresses, and trained more than 300 specialists from all over the world in the Bunge Institute. He filmed many of his patients suffering from movement disorders. Hallervorden‐Spatz disease (HSD) was first described in 1922. The recognition of this well‐defined syndrome was followed by several case reports published and in 1936, a new case was reported by Ludo van Bogaert and Clovis Vincent. To the best of our knowledge, this case report can be considered as the first filmed case of HSD.

TransFix® for delayed flow cytometry of endothelial progenitor cells and angiogenic T cells.

Endothelial progenitor cells (EPC) and angiogenic T cells have not been validated for use in studies that involve delayed sample processing and analysis. Here, we report our results for the flow cytometric enumeration of circulating EPC and angiogenic T cells using TransFix®-treated whole blood obtained from adult patients with cardiovascular disease and healthy volunteers. Both cell types promote neovascularization and vascular homeostasis. As such they have been put forward as novel diagnostic markers for endothelial dysfunction and may add prognostic information in patients with cardiovascular disease. Our findings indicate that by the addition of TransFix® cellular antigen stabilizing reagent to whole blood, analyses can be postponed up to 7 days after blood collection. Therefore, this procedure may facilitate laboratory workflow, as well as the organization of multicenter studies, which requires analyses to be conducted in a central core laboratory.