Rapid in vitro biocompatibility assay of endovascular stents by flow cytometry using platelet activation and platelet-leukocyte aggregation

Abstract

Clinical studies suggest that stent design and surface texture are responsible for differences in biocompatibility of metallic endovascular stents. A simple in vitro experimental setup was established to test stent‐induced degree of platelet and leukocyte activation and platelet‐leukocyte aggregation by flow cytometry. Heparin‐coated tantalum stents and gold‐coated and uncoated stainless steel stents were tested. Stents were implanted into silicone tubes and exposed to blood from healthy volunteers. Platelet and leukocyte activation and percentage of leukocyte‐platelet aggregates were determined in a whole‐blood assay by subsequent staining for activation‐associated antigens (CD41a, CD42b, CD62p, and fibrinogen binding) and leukocyte antigens (CD14 and CD45) and flow cytometric analysis. Blood taken directly after venous puncture or exposed to the silicone tube alone was used as negative controls. Positive control was in vitro stimulation with thrombin receptor activating peptide (TRAP‐6). Low degree of platelet activation and significant increase in monocyte‐ and neutrophil‐platelet aggregation were observed in blood exposed to stents (P < 0.05). In addition, leukocyte activation was induced as measured by increased CD45 and CD14 expression. Heparin coated stents continuously induced less platelet activation and leukocyte‐platelet aggregation than uncoated stainless steel stents of the same length and shorter stents of the same structure. Stent surface coating and texture plays a role in platelet and leukocyte activation and leukocyte‐platelet aggregation. Using this simple in vitro assay and whole blood and flow cytometry, it seems possible to differentiate stents by their potency to activate platelets and/or leukocytes. This assay could be applied for improving the biocompatibility of coronary stents. Cytometry (Comm. Clin. Cytometry) 38:30–39, 1999. © 1999 Wiley‐Liss, Inc.

Spontaneous Echo Contrast Caused by Platelet and Leukocyte Aggregates?

“…Blood sample preparation was based on the consensus protocol for flow cytometric analysis of platelet function, 9 with slight modifications. 10 …”

Biocompatible hydrogel supports the growth of respiratory epithelial cells: Possibilities in tracheal tissue engineering

“…22,23 Leukocytes show an altered expression of various surface marker proteins on contact with noncompatible materials, 24 and the quantification of these markers by flow cytometry has been used as a tool to assess material incompatibility. 25 Comparable and unaltered expression profiles (p > 0.05) for CD11b/CD18, 26 CD45, 27 and CD14 27 by macrophages cultured on the hydrogel and TCPS control (Fig. 3) suggest the hydrogel's nonactivated nature toward macrophages.…”

Clovamide-Type Phenylpropenoic Acid Amides,N-Coumaroyldopamine andN-Caffeoyldopamine, Inhibit Platelet-Leukocyte Interactions via Suppressing P-Selectin Expression

“…Data were acquired for 10,000 platelets, and the extent of exposure of CD62p was determined as the measure of platelet activation (FACSCalibur flow cytometer and Cell Quest Pro software; BD Biosciences, San Jose, CA). Fluorescein isothiocyanate (FITC)-conjugated rat anti-mouse CD62p (P-selectin) monoclonal antibody and the isotype control were obtained from BD Biosciences (Tá rnok et al, 1999;Ahn et al, 2005).…”

“…Antibodies used to identify blood cells were as follows: R-phycoerythrin (PE) rat antimouse CD41 and isotype control R-PE-conjugated rat IgG 1 (BD Biosciences) for platelets and FITC rat anti-mouse CD45 and isotype control FITC-conjugated rat IgG 2b (Serotec, Raleigh, NC) for leukocytes. Platelet-leukocyte interactions were determined by flow cytometry as described previously (Tá rnok et al, 1999).…”