Controlled release of paclitaxel using a drug-eluting stent through modulation of the size of drug particles in vivo

Paclitaxel-coated balloon catheter for benign esophageal stenosis in a rabbit model

Most patients with benign esophageal stenosis require multiple or even continuous balloon dilation treatments to achieve symptom relief. In this study, eighteen rabbits were used to establish an esophageal benign stenosis model and were divided into a control group (n = 6), a balloon group (n = 6) and a PTX-coated balloon group (n = 6) to evaluate the feasibility and effectiveness of paclitaxel (PTX)-coated balloons for the rabbit esophageal benign stenosis model. The weight and esophageal diameter were recorded every 2 weeks until 8 weeks post-surgery. Hematoxylin-eosin staining, Masson's trichrome staining and immunohistochemical staining were performed for pathological analysis. Four weeks post-operation, there was a significant difference in weight between the control group and the balloon group (p = 0.01) and between the control group and the PTX balloon group (p = 0.01). There was a significant difference in the esophageal diameter between the balloon group and the PTX balloon group at 8 weeks post-operation (p = 0.02). Four weeks post-operation, the degree of inflammatory cell infiltration in the PTX balloon group was significantly lower than that in the control group (p = 0.002) and balloon group (p = 0.001). The degree of collagen deposition in the PTX balloon group was significantly lower than that in the control group (p = 0.002) and balloon group (p = 0.03). Eight weeks post-operation, the percentage of cells positive for TGF-β (p < 0.001), the degree of inflammatory cell infiltration (p = 0.02) and the degree of collagen deposition (p = 0.02) in the PTX balloon group were significantly lower than those in the balloon group. Therefore, PTX-coated balloons may alleviate the local inflammatory response and collagen deposition when used during dilation treatment of benign esophageal stenosis.

Study of functional drug-eluting stent in promoting endothelialization and antiproliferation

Drug-eluting stents have been widely used in the clinic because of their impressive ability to reduce restenosis. However, the conventional biodegradable polymers used for drug-loaded coatings undergo bulk erosion, which can induce internal catalysis, resulting in a high local acidity during the degradation process and unfavorable side-effects. Herein, poly(1,3-trimethylene carbonate), a surface eroding biodegradable polymer, was chosen as a drug-loaded coating for cardiovascular stents. We modified both sides of the stent to simultaneously promote re-endothelialization at the inner layer and reduce restenosis at the outer layer, using a titanium oxide (Ti-O) film as the inner layer and a Ti-O film/drug coating as the outer layer. In vitro and in vivo results indicated that the Ti-O film accelerated endothelial cell growth and re-endothelialization, and the drug coating inhibited platelet adhesion, activation, and aggregation, smooth muscle cell proliferation, and significantly reduced neointimal hyperplasia. Therefore, this novel stent may have potential as a cardiovascular stent to treat patients with coronary artery stenosis.