Abstract 2038: Statin Targeted Treatment Against Intimal Hyperplasia Using Unique Chitosan-PLGA Nanoparticles

Introduction: Statins have beneficial pleiotropic effects, including reducing intimal hyperplasia (IH) after intervention for peripheral arterial disease. Using a unique nanoparticle (NP) to locally maximize statin’s pleiotropic benefits, we hypothesized chitosan-functionalized polylactic-co-glycolic nanoparticles loaded with simvastatin (SL-cNPs) would: 1) be taken up by endothelial cells (ECs) and vascular smooth muscle cells (VSMCs); 2) affect EC and VSMC function; and 3) reduce IH compared to systemic simvastatin. Methods: cNPs were loaded with simvastatin (2% w/w ) and encapsulated with lipophilic tracer, DiD. In vitro , human aortic ECs and VSMCs (passage 3-5) were cultured with 0.2mg SL-cNPs or basal media (30 min). After 24 hours, uptake of SL-cNPs was assessed by immunostaining and flow cytometry. Functional effect of SL-cNPs was determined using qPCR for mRNA expression of RhoA, RhoB and Ras. In vivo, male Sprague-Dawley rats (n=6-9/group) underwent carotid artery balloon injury in the following groups: 1) intraluminal therapy using normal saline control, empty cNPs or SL-cNPs; and 2) oral simvastatin (10mg/kg/day, 7 days pre-operative until sacrifice) plus intraluminal saline or SL-cNPs. Rats were sacrificed (day 14), perfusion fixed, arteries harvested, and IH quantified with morphometric analysis. Student’s t-test and one-way ANOVA was performed (p <0.05 for significance). Results: In vitro , SL-cNPs were readily taken up by ECs (79.6%, 38,606/48,501) and VSMCs (46.4%, 25,774/55,549). SL-cNPs induced a compensatory increase in expression of EC RhoA (1.3-fold) and VSMC RhoA (1.7-fold) and RhoB (5.4-fold) (p<0.05). In vivo, oral simvastatin plus intraluminal SL-cNPs reduced IH compared to controls (0.44 ± 0.04 vs 0.34 ± 0.03, p<0.05). Although oral simvastatin and SL-cNPs alone trended toward IH reduction, the effect was not significant (0.35 ± 0.03 and 0.377 ± 0.03, respectively). No difference existed between oral simvastatin and SL-cNP therapy. Conclusion: cNPs can be used as a novel vehicle to locally deliver statins to vascular cells. Although only the combination of oral simvastatin and SL-cNPs effectively reduced IH, different routes and/or concentration of SL-cNPs may allow for a more robust effect on IH prevention.