Simvastatin Nano-formulation Exhibited Protective Effect in Cellular Model of Atherosclerosis via Inhibition of Osteopontin Expression

Abstract

Background: Atherosclerosis is among the primary causes of mortality globally due to its ability to induce cardiovascular and cerebrovascular events. Osteopontin (OPN) is a pro-inflammatory cytokine that plays an important role in the development of atherosclerosis. Simvastatin, a lipid-lowering drug belonging to the statin class, is known to decrease plasma OPN levels. However, its unfavorable pharmacokinetic profile, characterized by extensive first-pass metabolism leading to poor bioavailability, has restricted its clinical use. Objectives: The present study aimed to assess the efficacy of a nano-formulation of simvastatin [folate-conjugated simvastatin silver (Ag) nano-formulation] in a cellular model of atherosclerosis. Methods: This interventional study was performed on adventitial fibroblasts obtained from rat aorta. The cell viability of aldosterone-stimulated adventitial fibroblasts was evaluated in the presence of simvastatin and its nano-formulation using the MTT (3-[4,5-dimethylthiazole-2-yl]2,5-diphenyltetrazolium bromide) assay and microscopic observation. The expression and quantification of OPN were performed using qPCR and ELISA, respectively. The presence of reactive oxygen species (ROS) was estimated using a fluorescent probe, dihydroethidine (DHE). Variation among data was computed using one-way ANOVA followed by post hoc analysis (Bonferroni post hoc test) using SPSS software (version 19.0, SPSS Inc., Chicago, IL). Results: The nano-formulation of simvastatin was most effective (P < 0.05) in retaining the viability of fibroblasts (300% at 10 μM, P < 0.001), which was significantly decreased (50% at 10 μM, P < 0.001) after aldosterone treatment. Additionally, the formulation prevented the aldosterone-induced increase in OPN expression in fibroblasts. However, ROS levels remained unaltered in all groups. Conclusions: The nano-formulation of simvastatin demonstrated a protective effect in a cellular model of atherosclerosis, likely due to its ability to prevent the increase in aldosterone-induced OPN expression. Assuming a favorable pharmacokinetic profile, owing to its reduced size and folate conjugation, the formulation warrants further investigation in the anti-atherosclerosis drug discovery program.