Here, we demonstrate that POSS-PCU surface immobilized anti-CD34 antibodies selectively captured CD34+cells from peripheral blood, although only a minority of these were EPCs. on anti-CD34-coated POSS-PCU surfaces was not significantly higher than that of POSS-PCU (5.01.0 vs. 1.70.6,p>0.05). However, antibody conjugation significantly improved hemocompatibility, as seen from the prolonged reaction and clotting times, decreased angle and maximum amplitude (p<0.05), as well as decreased platelet adhesion (76.87.8 vs. 8.40.7,p<0.05) and activation. Here, we demonstrate that POSS-PCU surface immobilized anti-CD34 antibodies selectively captured CD34+cells from peripheral blood, although only a minority of these were EPCs. Nevertheless, antibody conjugation significantly improves the hemocompatibility of POSS-PCU, and should therefore continue to be explored in combination with other strategies to improve the specificity of EPC capture to promotein situendothelialization. == Introduction == With the rapid advancement of interventional cardiology over the past decade, percutaneous coronary intervention (PCI) has become the treatment of choice for atherosclerotic coronary artery disease Mouse monoclonal to eNOS (CAD) [1]. Although PCI Rosiridin is widely viewed as an acceptable alternative to coronary artery bypass graft (CABG) surgery, the recent SYNTAX trial revealed that CABG should remain Rosiridin the standard of care for patients with complex lesions [2]. Nevertheless, the prevalence of PCI as a treatment for CAD warrants attention, especially in the realm of cardiovascular regenerative medicine. Majority of PCI involves plaque compression by balloon angioplasty, followed by the deployment of a stent, which acts as a permanent scaffold ensuring vessel patency. Early bare metal stents (BMS) were developed to limit post-angioplasty restenosis, although their success was limited by significant rates (15-30%) of in-stent restenosis (ISR) [3]. ISR is primarily a consequence of neointimal hyperplasia, which is a result of the body mounting an immunological response to the metal stent, as well as local mechanical vascular injury caused by stent deployment. Upregulation of inflammatory mediators and induction of thrombogenic cascades culminate in abnormal vascular smooth muscle cell (VSMC) proliferation, smooth muscle hypertrophy and extracellular matrix deposition, which result in luminal narrowing and vessel re-occlusion [4-8]. The introduction of polymer-coated drug-eluting stents (DES), which allow for localised delivery of anti-proliferative drugs such as sirolimus and paclitaxel to the neointima, was a key advance that resulted in dramatically reduced ISR rates of less than 10% in initial clinical trials. DES have thus become the standard of care and are used in over 85% of PCI [9]. Despite the clear short- to mid-term benefits of using DES over BMS, there have been concerns over the long-term safety of DES. Indeed, a recent meta-analysis in the Cochrane Review revealed that there were not statistically significant difference in death, acute myocardial infarction (MI), or thrombosis rates when comparing DES to BMS [10]. Furthermore, follow-up studies of patients who received first-generation DES (sirolimus- and paclitaxel-eluting stents) have revealed an association with increased cumulative incidence of very late (i.e., >1 year post-stenting) stent thrombosis (ST) [6]. ST is a life-threatening event, with mortality rates of up to 30%, and is postulated to be a result of nonselective drug inhibition of both endothelial cell (EC) and VSMC proliferation, which delay endothelial recovery [3,4]. Furthermore, an inflammatory reaction is induced by the polymer coating in which the drugs are dissolved in, and can cause delayed neointimal hyperplasia and restenosis. Moreover, to decrease the persistent risk of very late ST, long-term (6-12 months post-stenting) dual anti-platelet therapy (aspirin and clopidogrel) is required, and this in itself may bring about undesirable side effects such as hemorrhagic complications and thrombotic thrombocytopenic purpura. As rates of late ST remain higher with DES, the actual long-term benefits of DES over BMS have been called into Rosiridin question [11-15]. There is therefore an urgent need to develop new methods Rosiridin of circumventing both the problems of ISR and thrombosis seen in BMS and DES, for which endothelialization of the stent surface has emerged as a promising approach. A hemocompatible polymer stent coating is therefore a crucial element, as while it must act as a protective coating for the bare metal surface to prevent the problem of ISR as seen with BMS, it must.
Here, we demonstrate that POSS-PCU surface immobilized anti-CD34 antibodies selectively captured CD34+cells from peripheral blood, although only a minority of these were EPCs
