See also Shantsila E, Blann AD, Lip GYH. Circulating endothelial cells: from bench to clinical practice.This issue, pp 865-8.Summary. Background: Circulating endothelial cells (CECs) have emerged as non-invasive biomarkers of vascular dysfunction. The most widely used method for their detection is CD146-based immunomagnetic separation (IMS). Although this approach has provided consensus values in both normal and pathologic situations, it remains tedious and requires a trained operator. Objectives: Our objective was to evaluate a new hybrid assay for CEC measurement using a combination of preenrichment of CD146+ circulating cells and multiparametric flow cytometry measurement (FCM). Patients and methods: CECs were determined in peripheral blood from 20 healthy volunteers, 12 patients undergoing coronary angioplasty, and 30 renal transplant recipients, and blood spiked with cultured endothelial cells. CD146+ cells were isolated using CD146-coated magnetic nanoparticles and labeled using CD45-fluorescein isothiocyanate and CD146-PE or isotype control antibody and propidium iodide before FCM. The same samples were also processed using CD146-based immunomagnetic separation as the reference method. Results: The hybrid assay detected CECs, identified as CD45

Endothelial dysfunction occurs in hemodialysis and kidney-transplanted patients and can be enhanced by immunosuppressive therapy. Circulating endothelial cells (CEC), endothelial microparticles (EMP) and sVCAM-1 provide information on endothelium activation and damage.We compared the impact of two immunosuppressive regimens (CsA/Aza vs. Tac/MMF) on the kinetics of CEC, EMP and sVCAM-1 levels in 52 patients, both before graft and 3, 6, 9 and 12 months after graft, in reference to 50 healthy controls.CEC, EMP and sVCAM-1 levels were significantly decreased 1 year after transplantation (M12) as compared to pretransplant values. At M12, CEC and sVCAM-1 levels were significantly higher than those of controls whereas EMP reached normal values. Nine months postgraft, lower CEC and normalized EMP levels were found in patients receiving cyclosporine microemulsion/ azathioprine (CsA/Aza) when compared to patients treated with tacrolimus/ mycophenolate mofetil (Tac/MMF). Multivariate analysis evidenced positive correlations between CEC and history of cardiovascular diseases and between EMP and cytomegalovirus infection at M12.In conclusion, our combined analysis of endothelial injury markers confirms the favorable impact of renal transplantation on endothelium, and show that CEC levels discriminate treatment-associated endothelial toxicity. These results enlighten the potential of these noninvasive blood biomarkers in indexing vascular injury and optimize therapeutic options.

The profile of circulating endothelial markers shows massive endothelial activation and repair/remodeling during AI-TTP, and suggests that CECs and EPCs may be promising prognostic biomarkers of the disease.