Circulating endothelial cells as biomarker for cardiovascular diseases

Abstract

BackgroundEndothelial dysfunction is involved in several cardiovascular diseases. Elevated levels of circulating endothelial cells (CECs) and low levels of endothelial progenitor cells (EPCs) have been described in different cardiovascular conditions, suggesting their potential use as diagnostic biomarkers for endothelial dysfunction. Compared to typical peripheral blood leukocyte subsets, CECs and EPCs occur at very low frequency. The reliable identification and characterization of CECs and EPCs is a prerequisite for their clinical use, however, a validated method to this purpose is still missing but a key for rare cell events.ObjectivesTo establish a validated flow cytometric procedure in order to quantify CECs and EPCs in human whole blood.MethodsIn the establishment phase, the assay sensitivity, robustness, and the sample storage conditions were optimized as prerequisite for clinical use. In a second phase, CECs and EPCs were analyzed in heart failure with preserved (HFpEF) and reduced (HFrEF) ejection fraction, in arterial hypertension (aHT), and in diabetic nephropathy (DN) in comparison to age‐matched healthy controls.ResultsThe quantification procedure for CECs and EPCs showed high sensitivity and reproducibility. CEC values resulted significantly increased in patients with DN and HFpEF in comparison to healthy controls. CEC quantification showed a diagnostic sensitivity of 90% and a sensitivity of 68.0%, 70.4%, and 66.7% for DN, HFpEF, and aHT, respectively.ConclusionA robust and precise assay to quantify CECs and EPCs in pre‐clinical and clinical studies has been established. CEC counts resulted to be a good diagnostic biomarker for DN and HFpEF.

The Blood Circulating Rare Cell Population. What Is It and What Is It Good for?

“…Consequently, it is worthwhile to investigate several phenotypes at the same time to obtain greater picture of the disorder [96]. In contrast to mature EnC, EPC numbers were often reported to be inversely correlated with disease [98]. One of the big-interest marker applications beside cancer is the prediction of MI related death as well as cardiovascular risk assessment [99].…”

Fluid-based assays and precision medicine of cardiovascular diseases: the ‘hope’ for Pandora’s box?

“…AMI, acute myocardial infarction; CECs, circulating endothelial cells; CHD, coronary heart disease; CV, cardiovascular; cfDNA, circulating cell-free DNA; dd-cfDNA, donor-derived cfDNA; dn, diabetic nephropathy; EPCs, endothelial progenitor cells; FAM101A, refilin a; HFpEF, heart failure preserved ejection fraction; miRNA, micro-RNA; PAH, pulmonary arterial hypertension. et al 20 have established a robust flow cytometric assay for CEC and EPC quantification in 101 patients affected by HF, diabetic nephropathy (DN) and hypertension (HT) compared with 11 controls. Evidence from this study reported that increased CEC counts may be a reliable diagnostic biomarker for DN and HF with preserved ejection fraction (EF).…”

“…Evidence from this study reported that increased CEC counts may be a reliable diagnostic biomarker for DN and HF with preserved ejection fraction (EF). 20 Another case-control study evaluated a correlation between the percentage of CECs and levels of endothelin-1 (ET-1) in peripheral whole blood isolated from 15 left-to-right shunt CHD without PAH, 26 CHD complicated with mild PAH and 17 CHD complicated with moderate-to-severe PAH with respect to 30 controls. 42 From results, an increased CEC number causing ET-1 production was observed in patients with CHD-PAH, suggesting that a combination of CECs and ET-1 may be used to define therapeutic strategies for control of PAH onset.…”

“…Rather, advanced fluidbased assays better describe the modern complex technologies able to detect circulating intact cells and cell-free nucleic acids, circulating epigeneticsensitive molecules (DNA methylated, modified histones and non-coding RNAs), circulating metabolites and other cell products, such as microvesicles and exosomes in CV diseases. [19][20][21][22] Could liquid biopsy represent the 'the hope' for Pandora's box in precision medicine of CV diseases? We summarise the main advantages and limitations of several liquid biopsy approaches with respect to traditional endomyocardial biopsy (EMB) and discuss their putative clinical applications for personalised therapy of Review some CV diseases, mainly coronary heart disease (CHD), acute myocardial infarction (AMI), HF and pulmonary arterial hypertension (PAH).…”

Editorial comment: variables affecting the presence of mesenchymal stromal cells in the peripheral blood and their relationship with apheresis product

“…In analogy to identification of MSCs within tissues (Mendez‐Ferrer et al , ; Consentius et al , ), a crucial aspect for flow cytometry‐based identification of circulating endothelial, haematopoietic, or mesenchymal progenitor lineages is their clear phenotypic distinction with appropriate marker panels (Pitchford et al , ). Of importance is their distinction from circulating HSCs (Mendez‐Ferrer et al , ), circulating EPCs and also circulating mature endothelial cells (CEC) (Asahara et al , ; Lanuti et al , ; Farinacci, et al , ). In particular, the latter two are phenotypically closely related to MSCs, also adhere to culture plastic, and may therefore potentially easily be mistaken for MSCs.…”