Fabrication of a silver particle-integrated silicone polymer-covered metal stent against sludge and biofilm formation and stent-induced tissue inflammation

Abstract

To reduce tissue or tumor ingrowth, covered self-expandable metal stents (SEMSs) have been developed. The effectiveness of covered SEMSs may be attenuated by sludge or stone formation or by stent clogging due to the formation of biofilm on the covering membrane. In this study, we tested the hypothesis that a silicone membrane containing silver particles (Ag-P) would prevent sludge and biofilm formation on the covered SEMS. In vitro, the Ag-P-integrated silicone polymer-covered membrane exhibited sustained antibacterial activity, and there was no definite release of silver ions from the Ag-P-integrated silicone polymer membrane at any time point. Using a porcine stent model, in vivo analysis demonstrated that the Ag-P-integrated silicone polymer-covered SEMS reduced the thickness of the biofilm and the quantity of sludge formed, compared with a conventional silicone-covered SEMS. In vivo, the release of silver ions from an Ag-P-integrated silicone polymer-covered SEMS was not detected in porcine serum. The Ag-P-integrated silicone polymer-covered SEMS also resulted in significantly less stent-related bile duct and subepithelium tissue inflammation than a conventional silicone polymer-covered SEMS. Therefore, the Ag-P-integrated silicone polymer-covered SEMS reduced sludge and biofilm formation and stent-induced pathological changes in tissue. This novel SEMS may prolong the stent patency in clinical application.

Aspirin for metal stent in malignant distal common bile duct obstruction (AIMS): study protocol for a multicenter randomized controlled trial

“…Research trends show that physicians are mainly focused on the mechanical aspects of SEMS to increase patency, and the structure and composition of these stents are constantly evolving [31][32][33][34]. Despite this, the need for improved stent patency has not been met because of the lack of research on chemical prophylaxis for stent patency.…”

“…It is known that aspirin leads to cell apoptosis by inhibiting Bcl-2 expression and downregulating COX-2 expression, which is known to convert arachidonic acid to prostaglandins, and it may reduce tumorcell invasion through the downregulation of MMP-2 expression [41,42]. Some studies have also provided evidence that aspirin promotes deoxyribonucleic acid (DNA) self-healing by the upregulation of hMLH1, hMSH2, hMSH6, hPMS2 [43], and XRCC expression [44], slowing down gene-mutation accumulation, and protecting normal cell DNA [32,45]. Recent studies have suggested several new aspirin pathways, such as inhibiting the synthesis of prostaglandin E2 (PGE2) [46], controlling the number of circulating platelets and their activity levels to evade several innate anti-tumor effects [47][48][49][50], increasing chemo-agent toxicity, and downregulating cellular drug resistance [51,52].…”

Aspirin for metal stent in malignant distal common bile duct obstruction (AIMS): Study protocol for a multicenter randomized controlled trial

“…[30] Research trends show that physicians are mainly focused on the mechanical aspects of SEMS to increase patency, and the structure and composition of these stents are constantly evolving. [31][32][33][34] Despite this, the need for improved stent patency has not been met because of the lack of research on chemical prophylaxis for stent patency. Based on the study of Jang et al, [11] we will investigate whether aspirin use after index ERBD with SEMS for malignant distal CBD obstruction is effective and safe.…”

Aspirin for metal stent in malignant distal common bile duct obstruction (AIMS): Study protocol for a multicenter randomized controlled trial

“…[27] Research trends show that physicians are mainly focused on the mechanical aspects of SEMS to increase patency, and the structure and composition of these stents are constantly evolving. [28][29][30][31] Despite this, the need for improved stent patency has not been met because of the lack of research on chemical prophylaxis for stent patency. Based on the study of Jang et al, [11] we will investigate whether aspirin use after index ERBD with SEMS for malignant distal CBD obstruction is effective and safe.…”

“…[38,39] Some studies have also provided evidence that aspirin promotes DNA self-healing by the upregulation of hMLH1, hMSH2, hMSH6, hPMS2, [40] and XRCC expression, [41] slowing down gene mutation accumulation, and protecting normal cell DNA. [29,42] Recent studies have suggested several new aspirin pathways, such as inhibiting the synthesis of PGE2, [43] controlling the number of circulating platelets and their activity levels to evade several innate anti-tumor effects, [44][45][46][47] increasing chemo agent toxicity, and downregulating cellular drug resistance. [48,49] Since the results of these basic studies have mostly been conducted in vitro and have not been proven in humans, these outcomes cannot be presented as definitive mechanisms of aspirin.…”