Peptides surface modification to prevent stent blockage

描述（由申请人提供）：胆道支架堵塞是内镜支架置入术缓解恶性梗阻性黄疸的主要并发症。细菌通过它们的皮利粘附在支架表面，并且还通过产生糖萼形成细菌生物膜。胆道支架由于细菌生物膜的形成和支架腔内污泥的积累而被堵塞。细菌β-葡萄糖醛酸苷酶使胆红素二葡萄糖醛酸苷解结合，导致胆红素钙沉淀，从而形成胆汁淤积物。这归因于需氧细菌如E.大肠杆菌和厌氧细菌如C.产气荚膜杆菌 已经尝试了不同的方法来防止细菌附着和支架堵塞，包括使用不同的塑料材料、改变支架设计、生物杀灭剂浸渍和全身抗生素预防。然而，这些方法都没有产生显著的临床效益。 小分子多肽可能影响细菌基因/酶活性的表达并影响其粘附特性。在这个项目中，我们使用“一珠一化合物”组合文库方法探索肽表面修饰的潜在益处。这种新的高通量技术可以筛选大量可能影响细菌粘附的不同肽。 在实验的第一部分，我们研究了单菌E. coli和E.大肠杆菌和肠球菌与许多预先生成的肽表面，以鉴定抗细菌附着的肽。使用自动微测序鉴定这些选择的肽的氨基酸序列。然后合成大量特异性纯化的抗性肽，并用于涂覆和修饰塑料支架。然后用特殊的流动室或改良的罗宾斯装置测试这些抗性肽涂层支架在延迟或防止细菌附着方面的作用。如果在体外研究中观察到显著获益，则将提出一项随机对照临床研究来确定耐药肽涂层支架的获益。研究结果可能为预防慢性植入医疗器械相关感染，特别是延长塑料支架通畅性提供新的线索。

DESCRIPTION (provided by applicant): Biliary stent blockage is the major complication of endoscopic stenting for the palliation of malignant obstructive jaundice. Bacteria adhere to the stent surface with their pili and also through the production of glycocalyx to form a bacterial biofilm. Biliary stents become blocked as a result of bacterial biofilm formation and accumulation of sludge within the lumen of the stent. Biliary sludge formed as a result of deconjugation of bilirubin diglucuronide by bacterial Beta-glucuronidase, resulting in the precipitation of calcium bilirubinate. This is attributed to enzymatic activities of aerobic bacteria such as E. coli and anaerobic bacteria such as C. perfringens. Different methods have been tried to prevent bacterial attachment and stent blockage including use of different plastic materials, changing stent designs, biocide impregnation and systemic antibiotic prophylaxis. However, none of these methods have produced significant clinical benefits. Small molecular peptides may influence the bacterial expression of gene/enzyme activities and affect their adherence characteristics. In this project, we explore the potential benefits of peptide surface modification using the "one-bead one-compound" combinatorial library method. This novel high through put technique can screen large numbers of different peptides that may affect bacterial adherence. In the first part of the experiment, we study the interaction between single bacteria E. coli and a mixed culture of E. coli and Enterococcus with a number of pre-generated peptide surfaces to identify peptide(s) that resist bacterial attachment. The amino acids sequence of these selected peptides are identified using automatic microsequencing. Large quantity of the specific purified resistant peptides are then synthesized and used to coat and modify plastic stents. The effects of these resistant peptide coated stents in delaying or preventing bacterial attachment is then tested with a special flow chamber or Modified Robbins Device. If significant benefit is observed with the in-vitro studies, a randomized controlled clinical study will be proposed to determine the benefits of the resistant peptide coated stents. The results may shed new lights in the prevention of chronic implanted medical device related infections and specifically in prolonging plastic stent patency.