Combination treatment with asiaticoside and rapamycin: A new hope for in-stent restenosis

The aim of this study was to investigate and characterize the efficacy and mechanism of action of asiaticoside in combination with rapamycin in the inhibition of in-stent restenosis (ISR). The effects of asiaticoside combined with rapamycin on cell proliferation in vitro were evaluated by MTT assay. The mRNA expression was analyzed by quantitative polymerase chain reaction (qPCR). Enzyme-linked immunosorbent assay (ELISA) was used to confirm protein synthesis. The cell growth inhibition rate in the combination group was significantly higher compared with those in the asiaticoside and rapamycin groups for human aortic fibroblasts (HAFs; 63.50±3.83, 53.06±8.10 and 60.34±4.9%, respectively) and human aortic smooth muscle cells (HASMCs; 33.12±1.35, 26.21±7.59 and 28.27±4.92, respectively; P<0.05). However, for human coronary artery endothelial cells (HCAECs), the cell growth inhibition rates in the combination, asiaticoside and rapamycin groups were 11.09±1.17, 26.22±4.24 and 34.80±2.80%, respectively (P<0.05), as detected by MTT assay. The qPCR assay showed that in the combination group the level of von Willebrand factor (vWF) mRNA was downregulated, while platelet endothelial cell adhesion molecule (PECAM-1) and endothelial nitric oxide synthase (eNOS) mRNAs were upregulated in HCAECs compared with the rapamycin group (P<0.05). Transforming growth factor (TGF)-β1 and TIMP1 mRNAs were downregulated while Smad7 and matrix metalloproteinase 1 (MMP1) mRNAs were upregulated in HAFs compared with the rapamycin and AT groups (P<0.05). The ELISA showed that the type I collagen level was significantly reduced in HASMCs and HAFs (P<0.05). The data suggest that asiaticoside combined with rapamycin may be effective in the reduction of ISR.