title: Low-dose sirolimus-eluting hydroxyapatite coating on stents does not increase platelet activation and adhesion ex vivo.
abstract: We previously found paclitaxel-eluting polymer-coated stents causing more human platelet-monocyte complex formation than bare metal stents in vitro. Presently, we examined patterns of platelet activation and adhesion after exposure to 6 nanofilm HAp-coated (HAp-nano) stents, 6 HAp-microporous-coated (HAp-micro) stents, 5 HAp sirolimus-eluting microporous-coated (HAp-SES) stents and 5 cobalt-chromium stents (BMS) deployed in an in vitro flow system. Blood obtained from healthy volunteers was circulated and sampled at 0, 10, 30 and 60 min. By flow cytometry, there were no significant differences in P-Selectin expression between the 4 stent types (HAp-nano = 32.5%; HAp-micro = 42.5%, HAp-SES = 10.23%, BMS = 7% change from baseline at 60 min, p = NS); PAC-1 antibody binding (HAp-nano = 11.8%; HAp-micro = 2.9%, HAp-SES = 18%, BMS = 6.4% change from baseline at 60 min, p = NS) or PMC formation (HAp-nano = 21.6%; HAp-micro = 4%, HAp-SES = 6.6%, BMS = 17.4% change from baseline at 60 min, p = NS). The 4 stent types did not differ in the average number of platelet clusters >10 μm in diameter by SEM (HAp-nano = 2.39 ± 5.75; HAp-micro = 2.26 ± 3.43; HAp-SES = 1.93 ± 3.24; BMS = 1.94 ± 2.41, p = NS). The majority of the struts in each stent group were only mildly covered by platelets, (HAp-nano = 80%, HAp-micro = 61%, HAp-SES = 78% and BMS = 52.1%, p = NS). The HAp-microporous-coated stents (ECD) attracted slightly more proteinaceous material than bare metal stents (HAp-micro = 35% struts with complete protein coverage, P < 0.0001 vs. other 3 stent types). In conclusion, biomimetic stent coating with nanofilm or microporous hydroxyapatite, even when eluting low-dose sirolimus, does not increase the platelet activation in circulating human blood, or platelet adhesion to stent surface when compared to bare metal stents in vitro.
authors.affiliation: Skirball Center for Cardiovascular Research, Cardiovascular Research Foundation, 8 Corporate Drive, Orangeburg, NY 10962, USA.
authors.forename: Carlos L
authors.initials: CL
authors.lastname: Alviar
authors.forename: Armando
authors.initials: A
authors.lastname: Tellez
authors.forename: Michael
authors.initials: M
authors.lastname: Wang
authors.forename: Pamela
authors.initials: P
authors.lastname: Potts
authors.forename: Doug
authors.initials: D
authors.lastname: Smith
authors.forename: Manus
authors.initials: M
authors.lastname: Tsui
authors.forename: Wladyslaw
authors.initials: W
authors.lastname: Budzynski
authors.forename: Albert E
authors.initials: AE
authors.lastname: Raizner
authors.forename: Neal S
authors.initials: NS
authors.lastname: Kleiman
authors.forename: Eli I
authors.initials: EI
authors.lastname: Lev
authors.forename: Juan F
authors.initials: JF
authors.lastname: Granada
authors.forename: Greg L
authors.initials: GL
authors.lastname: Kaluza
mesh_terms: D000328:Adult; D020099:Coated Materials, Biocompatible; D054855:Drug-Eluting Stents; D017886:Durapatite; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D008297:Male; D008422:Materials Testing; D015539:Platelet Activation / Q000187:drug effects*; D020123:Sirolimus / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D020099:Coated Materials, Biocompatible; D007166:Immunosuppressive Agents; D017886:Durapatite; D020123:Sirolimus