Monocyte-derived and CD34+/KDR+ endothelial progenitor cells in heart failure

Circulating stem cells and cardiovascular outcomes: from basic science to the clinic

The cardiovascular and haematopoietic systems have fundamental inter-relationships during development, as well as in health and disease of the adult organism. Although haematopoietic stem cells (HSCs) emerge from a specialized haemogenic endothelium in the embryo, persistence of haemangioblasts in adulthood is debated. Rather, the vast majority of circulating stem cells (CSCs) is composed of bone marrow-derived HSCs and the downstream haematopoietic stem/progenitors (HSPCs). A fraction of these cells, known as endothelial progenitor cells (EPCs), has endothelial specification and vascular tropism. In general, the levels of HSCs, HSPCs, and EPCs are considered indicative of the endogenous regenerative capacity of the organism as a whole and, particularly, of the cardiovascular system. In the last two decades, the research on CSCs has focused on their physiologic role in tissue/organ homoeostasis, their potential application in cell therapies, and their use as clinical biomarkers. In this review, we provide background information on the biology of CSCs and discuss in detail the clinical implications of changing CSC levels in patients with cardiovascular risk factors or established cardiovascular disease. Of particular interest is the mounting evidence available in the literature on the close relationships between reduced levels of CSCs and adverse cardiovascular outcomes in different cohorts of patients. We also discuss potential mechanisms that explain this association. Beyond CSCs' ability to participate in cardiovascular repair, levels of CSCs need to be interpreted in the context of the broader connections between haematopoiesis and cardiovascular function, including the role of clonal haematopoiesis and inflammatory myelopoiesis.

Adverse Cardiac Remodelling after Acute Myocardial Infarction: Old and New Biomarkers

The prevalence of heart failure (HF) due to cardiac remodelling after acute myocardial infarction (AMI) does not decrease regardless of implementation of new technologies supporting opening culprit coronary artery and solving of ischemia-relating stenosis with primary percutaneous coronary intervention (PCI). Numerous studies have examined the diagnostic and prognostic potencies of circulating cardiac biomarkers in acute coronary syndrome/AMI and heart failure after AMI, and even fewer have depicted the utility of biomarkers in AMI patients undergoing primary PCI. Although complete revascularization at early period of acute coronary syndrome/AMI is an established factor for improved short-term and long-term prognosis and lowered risk of cardiovascular (CV) complications, late adverse cardiac remodelling may be a major risk factor for one-year mortality and postponded heart failure manifestation after PCI with subsequent blood flow resolving in culprit coronary artery. The aim of the review was to focus an attention on circulating biomarker as a promising tool to stratify AMI patients at high risk of poor cardiac recovery and developing HF after successful PCI. The main consideration affects biomarkers of inflammation, biomechanical myocardial stress, cardiac injury and necrosis, fibrosis, endothelial dysfunction, and vascular reparation. Clinical utilities and predictive modalities of natriuretic peptides, cardiac troponins, galectin 3, soluble suppressor tumorogenicity-2, high-sensitive C-reactive protein, growth differential factor-15, midregional proadrenomedullin, noncoding RNAs, and other biomarkers for adverse cardiac remodelling are discussed in the review.

Qishenyiqi dripping pill improves ventricular remodeling and function in patients with chronic heart failure: A pooled analysis

BACKGROUND

Qishenyiqi dripping pill for chronic heart failure (CHF) remains controversial due to lack of high-quality trials. Therefore, we conduct this pooled-analysis to evaluate the efficacy and safety of Qishenyiqi in CHF patients.

METHODS

We searched for randomized clinical trials for Qishenyiqi dripping pill in treating CHF up to August 2018 through China National Knowledge Infrastructure (CNKI), the PubMed Database, the Wanfang Database, the China Scientific Journal Database (VIP), and the Chinese Biomedicine Literature Service System. RevMan 5.3 was used for pooled analyses. Based on the New York Heart Association (NYHA) classification, the clinical therapeutic effect was collected as the primary endpoint.

RESULTS

The efficacy and safety of Qishenyiqi combined with routine treatment significantly increased NYHA functional classification, left ventricular ejection fraction, cardiac index, and 6-minute walking test and decreased brain natriuretic peptide, left ventricular end-diastolic, and end-systolic dimensions with no obvious side effects in comparison with routine therapy alone.

CONCLUSIONS

Together these results provide important insights into Qishenyiqi is effective and safe in improving ventricular remodeling and function of CHF patients.

PROSPERO REGISTRATION NUMBER

PROSPERO106695.

Endothelial Regenerative Capacity and Aging: Influence of Diet, Exercise and Obesity

Background:

The endothelium plays an important role in cardiovascular regulation, from blood flow to platelet aggregation, immune cell infiltration and demargination. A dysfunctional endo-thelium leads to the onset and progression of Cardiovascular Disease (CVD). The aging endothelium displays significant alterations in function, such as reduced vasomotor functions and reduced angio-genic capabilities. This could be partly due to elevated levels of oxidative stress and reduced endothe-lial cell turnover. Circulating angiogenic cells, such as Endothelial Progenitor Cells (EPCs) play a significant role in maintaining endothelial health and function, by supporting endothelial cell prolifera-tion, or via incorporation into the vasculature and differentiation into mature endothelial cells. Howev-er, these cells are reduced in number and function with age, which may contribute to the elevated CVD risk in this population. However, lifestyle factors, such as exercise, physical activity obesity, and dietary intake of omega-3 polyunsaturated fatty acids, nitrates, and antioxidants, significantly af-fect the number and function of these circulating angiogenic cells.

Conclusion:

This review will discuss the effects of advancing age on endothelial health and vascular regenerative capacity, as well as the influence of diet, exercise, and obesity on these cells, the mecha-nistic links and the subsequent impact on cardiovascular health

Circulating angiogenic stem cells in type 2 diabetes are associated with glycemic control and endothelial dysfunction

Circulating angiogenic cells (CACs) of various described phenotypes participate in the regeneration of the damaged endothelium, but the abundance of these cells is highly influenced by external cues including diabetes. It is not entirely clear which CAC populations are most reflective of endothelial function nor which are impacted by diabetes. To answer these questions, we enrolled a human cohort with variable CVD risk and determined relationships between stratified levels of CACs and indices of diabetes and vascular function. We also determined associations between CAC functional markers and diabetes and identified pro-angiogenic molecules which are impacted by diabetes. We found that subjects with low levels of CD34+/AC133+/CD31+/CD45dim cells (CAC-3) had a significantly higher incidence of diabetes (p = 0.004), higher HbA1c levels (p = 0.049) and higher CVD risk scores. Furthermore, there was an association between low CAC-3 levels and impaired vascular function (p = 0.023). These cells from diabetics had reduced levels of CXCR4 and VEGFR2, while diabetics had higher levels of certain cytokines and pro-angiogenic molecules. These results suggest that quantitative and functional defects of CD34+/AC133+/CD31+/CD45dim cells are associated with diabetes and vascular impairment and that this cell type may be a prognostic indicator of CVD and vascular dysfunction.

White blood cell differentials in dogs with congestive heart failure (CHF) in comparison to those in dogs without cardiac disease

OBJECTIVES

To determine if dogs with congestive heart failure have different white blood cell differential cell counts than dogs without cardiac disease.

MATERIALS AND METHODS

In total, 72 dogs with congestive heart failure and 143 controls were included in this retrospective study. Signalment, white blood cell differential counts and echocardiography data were retrieved. Basic statistical analysis was performed on white blood cell differential counts, and principal component analysis was used to compare these counts between cases and controls, with age, gender and case/control status as supplementary variables. Cases and controls were compared with binary logistic regression for the principal components identified and individual white blood cell differential counts. Principal component analysis of cases alone was conducted with age, gender, weight and mitral E wave:isovolumic relaxation time as supplementary variables. Linear regression analysis was used to explore the association between mitral E wave:isovolumic relaxation time and the principal components, weight, gender, age and diagnosis (mitral valve disease or dilated cardiomyopathy).

RESULTS

Among cases and controls, the largest variance in data (component 1) was associated with neutrophils, band neutrophils, monocytes and case status (P<0·01). The odds of an individual being a case increased 2·5-fold (95% confidence interval: 1·4 to 4·4) for each unit increase in component 1. Among the cases, mitral E wave:isovolumic relaxation time was associated with neutrophil count and case/control category.

CLINICAL SIGNIFICANCE

Dogs with congestive heart failure had a statistically significant increase in neutrophils, band neutrophils and monocytes in comparison with those without cardiac disease but the cell counts remained within normal reference intervals.

Progenitor Cells and Clinical Outcomes in Patients With Heart Failure

BACKGROUND

Endogenous regenerative capacity, assessed as circulating progenitor cell (PC) numbers, is an independent predictor of adverse outcomes in patients with cardiovascular disease. However, their predictive role in heart failure (HF) remains controversial. We assessed the relationship between the number of circulating PCs and the pathogenesis and severity of HF and their impact on incident HF events.

METHODS AND RESULTS

We recruited 2049 adults of which 651 had HF diagnosis. PCs were enumerated by flow cytometry as CD45med⁺ blood mononuclear cells expressing CD34, CD133, vascular endothelial growth factor receptor-2, and chemokine (C-X-C motif) receptor 4 epitopes. PC subsets were lower in number in HF and after adjustment for clinical characteristics in multivariable analyses, a low CD34⁺ and CD34⁺/CXCR⁺ cell count remained independently associated with a diagnosis of HF (P<0.01). PC levels were not significantly different in reduced versus preserved ejection fraction patients. In 514 subjects with HF, there were 98 (19.1%) all-cause deaths during a 2.2±1.5-year follow-up. In a Cox regression model adjusting for clinical variables, hematopoietic-enriched PCs (CD34⁺, CD34⁺/CD133⁺, and CD34⁺/CXCR4⁺) were independent predictors of all-cause death (hazard ratio 2.0, 1.6, 1.6-fold higher mortality, respectively; P<0.03) among HF patients. Endothelial-enriched PCs (CD34⁺/VEGF⁺) were independent predictors of mortality in patients with HF with preserved ejection fraction only (hazard ratio, 5.0; P=0.001).

CONCLUSIONS

PC levels are lower in patients with HF, and lower PC counts are strongly and independently predictive of mortality. Strategies to increase PCs and exogenous stem cell therapies designed to improve regenerative capacity in HF, especially, in HF with preserved ejection fraction, need to be further explored.

Vascular precursor cells in tissue injury repair

Vascular precursor cells include stem cells and progenitor cells giving rise to all mature cell types in the wall of blood vessels. When tissue injury occurs, local hypoxia and inflammation result in the generation of vasculogenic mediators which orchestrate migration of vascular precursor cells from their niche environment to the site of tissue injury. The intricate crosstalk among signaling pathways coordinates vascular precursor cell proliferation and differentiation during neovascularization. Establishment of normal blood perfusion plays an essential role in the effective repair of the injured tissue. In recent years, studies on molecular mechanisms underlying the regulation of vascular precursor cell function have achieved substantial progress, which promotes exploration of vascular precursor cell-based approaches to treat chronic wounds and ischemic diseases in vital organ systems. Verification of safety and establishment of specific guidelines for the clinical application of vascular precursor cell-based therapy remain major challenges in the field.

High-intensity Interval training enhances mobilization/functionality of endothelial progenitor cells and depressed shedding of vascular endothelial cells undergoing hypoxia

PURPOSE

Exercise training improves endothelium-dependent vasodilation, whereas hypoxic stress causes vascular endothelial dysfunction. Monocyte-derived endothelial progenitor cells (Mon-EPCs) contribute to vascular repair process by differentiating into endothelial cells. This study investigates how high-intensity interval (HIT) and moderate-intensity continuous (MCT) exercise training affect circulating Mon-EPC levels and EPC functionality under hypoxic condition.

METHODS

Sixty healthy sedentary males were randomized to engage in either HIT (3-min intervals at 40 and 80 % VO_2max for five repetitions, n = 20) or MCT (sustained 60 % VO_2max, n = 20) for 30 min/day, 5 days/week for 6 weeks, or to a control group (CTL) that did not received exercise intervention (n = 20). Mon-EPC characteristics and EPC functionality under hypoxic exercise (HE, 100 W under 12 % O₂) were determined before and after HIT, MCT, and CTL.

RESULTS

The results demonstrated that after the intervention, the HIT group exhibited larger improvements in VO_2peak, estimated peak cardiac output (Q_C), and estimated peak perfusions of frontal cerebral lobe (Q_FC) and vastus lateralis (Q_VL) than the MCT group. Furthermore, HIT (a) increased circulating CD14⁺⁺/CD16^-/CD34⁺/KDR⁺ (Mon-1 EPC) and CD14⁺⁺/CD16⁺/CD34⁺/KDR⁺ (Mon-2 EPC) cell counts, (b) promoted the migration and tube formation of EPCs, (c) diminished the shedding of endothelial (CD34^-/KDR⁺/phosphatidylserine⁺) cells, and (d) elevated plasma nitrite plus nitrate, stromal cell-derived factor-1, matrix metalloproteinase-9, and vascular endothelial growth factor-A concentrations at rest or following HE, compared to those of MCT. In addition, Mon-1 and -2 EPC counts were directly related to VO_2peak and estimated peak Q_C, Q_FC, and Q_VL.

CONCLUSIONS

HIT is superior to MCT for improving hemodynamic adaptation and Mon-EPC production. Moreover, HIT effectively enhances EPC functionality and suppresses endothelial injury undergoing hypoxia.

Prognostic relevance of circulating endothelial progenitor cells in patients with chronic heart failure

Novel strategies for a tailored risk prediction in chronic heart failure (CHF) are crucial to identify patients at very high risk for an improved patient management and to specify treatment regimens. Endothelial progenitor cells (EPCs) are an important endogenous repair mechanism with the ability to counteract endothelial injury and the possibility of new vessel formation. We hypothesised that exhaustion of circulating EPCs may be a suitable prognostic biomarker in patients with CHF. EPCs, defined as CD34+CD45dimKDR+ cells, were analysed using fluorescence-activated cell sorting. EPCs were measured in 185 patients with CHF including 87 (47 %) patients with ischaemic aetiology and 98 (53 %) patients with non-ischaemic CHF and followed for a median time of 2.7 years. During this period, 34.7 % of patients experienced the primary study endpoint all-cause mortality. EPC count was a significant and independent inverse predictor of mortality with an hazard ratio hazard ratio (HR) per increase of one standard deviation (1-SD) of 0.47 (95 % confidence interval [CI]: 0.35-0.61; p<0.001) and remained significant after multivariable adjustment for a comprehensive set of cardiovascular risk factors and potential confounders with a HR per 1-SD of 0.54 (95 % CI: 0.4-0.73; p<0.001). EPCs further demonstrated additional prognostic information indicated by improvements in C-statistic, net reclassification index and integrated discrimination increment. In conclusion, in our study circulating EPCs turned out as strong and independent inverse predictors of mortality underlining the importance of an impaired endothelial repair mechanism in the pathophysiology and progression of CHF.

Vascular Ageing and Exercise: Focus on Cellular Reparative Processes

Ageing is associated with an increased risk of developing noncommunicable diseases (NCDs), such as diabetes and cardiovascular disease (CVD). The increased risk can be attributable to increased prolonged exposure to oxidative stress. Often, CVD is preceded by endothelial dysfunction, which carries with it a proatherothrombotic phenotype. Endothelial senescence and reduced production and release of nitric oxide (NO) are associated with “vascular ageing” and are often accompanied by a reduced ability for the body to repair vascular damage, termed “reendothelialization.” Exercise has been repeatedly shown to confer protection against CVD and diabetes risk and incidence. Regular exercise promotes endothelial function and can prevent endothelial senescence, often through a reduction in oxidative stress. Recently, endothelial precursors, endothelial progenitor cells (EPC), have been shown to repair damaged endothelium, and reduced circulating number and/or function of these cells is associated with ageing. Exercise can modulate both number and function of these cells to promote endothelial homeostasis. In this review we look at the effects of advancing age on the endothelium and these endothelial precursors and how exercise appears to offset this “vascular ageing” process.

Mobilization of CD34+-progenitor cells in patients with severe trauma

Circulating CD34+ progenitor cells () gained importance in the field of regenerative medicine due to their potential to home in on injury sites and differentiate into cells of both endothelial and osteogenic lineages. In this study, we analyzed the mobilization kinetics and the numbers of CD34+, CD31+, CD45+, and CD133+ cells in twenty polytrauma patients (n = 13 male, n = 7 female, mean age 46.5±17.2 years, mean injury severity score (ISS) 35.8±12.5 points). In addition, the endothelial differentiation capacity of enriched CD34+cells was assessed by analyzing DiI-ac-LDL/lectin uptake, the expression of endothelial markers, and the morphological characteristics of these cells in Matrigel and spheroid cultures. We found that on days 1, 3, and 7 after a major trauma, the number of CD34+cells increased from 6- up to 12-fold (p<0.0001) over the number of CD34+cells from a control population of healthy, age-matched volunteers. The numbers of CD31+ cells were consistently higher on days 1 (1.4-fold, p<0.01) and 7 (1.3-fold, p<0.01), whereas the numbers of CD133+ cell did not change during the time course of investigation. Expression of endothelial marker molecules in CD34+cells was significantly induced in the polytrauma patients. In addition, we show that the CD34+ cell levels in severely injured patients were not correlated with clinical parameters, such as the ISS score, the acute physiology and chronic health evaluation II score (APACHE II), as well as the sequential organ failure assessment score (SOFA-2). Our results clearly indicate that pro-angiogenic cells are systemically mobilized after polytrauma and that their numbers are sufficient for the development of novel therapeutic models in regenerative medicine.

Circulating endothelial progenitor cells as a predictor of response to cardiac resynchronization therapy: the missing piece of the puzzle?

BACKGROUND

It would be important to better identify heart failure (HF) patients most likely to respond to cardiac resynchronization therapy (CRT). Because endothelial progenitor cells (EPCs) play a crucial role in the maintenance of vascular endothelium integrity, we hypothesize that patients who have higher circulating EPCs levels have greater neovascularization potential and are more prone to be responders to CRT.

METHODS

Prospective study of 30 consecutive patients, scheduled for CRT. Echocardiographic evaluation was performed before implant and 6 months after. Responders to CRT were defined as patients who were still alive, have not been hospitalized for HF management, and demonstrated ≥15% reduction in left ventricular end-systolic volume (LVESV) at the 6-month follow-up. EPCs were quantified before CRT, from peripheral blood, by flow cytometry using five different conjugated antibodies: anti-CD34, anti-KDR, anti-CD133, anti-CD45, and anti-CXCR4. We quantified five different populations of angiogenic cells: CD133(+) /CD34(+) cells, CD133(+) /KDR(+) cells, CD133(+) /CD34(+) /KDR(+) cells, CD45(dim) CD34(+) /KDR(+) cells, and CD45(dim) CD34(+) /KDR(+) /CXCR4(+) cells.

RESULTS

The proportion of responders to CRT at the 6-month follow-up was 46.7%. Responders to CRT presented higher baseline EPCs levels than nonresponders (0.0003 ± 0.0006% vs 0.0001 ± 0.0002%, P = 0.04, for CD34(+) /CD133(+) /KDR(+) and 0.0006 ± 0.0005% vs 0.0003 ± 0.0003%, P = 0.009, for CD45(dim) CD34(+) /KDR(+) /CXCR4(+) cells). In addition, baseline levels of CD45(dim) CD34(+) /KDR(+) /CXCR4(+) cells were positively correlated with the reduction of LVESV verified 6 months after CRT (r = 0.497, P = 0.008).

CONCLUSIONS

High circulating EPCs levels may identify the subset of HF patients who are more likely to undergo reverse remodeling and benefit from CRT. Addition of EPCs levels assessment to current selection criteria may improve the ability to predict CRT response.