Optimization of nonpyridinium oximes for BChE hydrolysis of OPs in plasma

描述(申请人提供)：本研究的主要目的是优化体外开发的基于丁酰胆碱酯酶(BChE)的催化清除剂系统，用于治疗急性有机磷(OP)中毒。由于过量OP对乙酰胆碱酯酶(AChE)的持续抑制作用，目前使用的肟类和阿托品联合疗法对高暴露OP中毒的治疗效果不佳。基于BChE作为化学计量清除剂的治疗新方法似乎昂贵得令人望而却步，每一次应用的价格标签为四位数。由于缺乏有效的BChE复活剂，BChE通过与肟类复活剂结合而从化学计量比转化为催化清除剂的过程一直受到阻碍。在我们的初步研究中，我们能够鉴定出一类独特的非传统结构支架的新型优质特异性BChE复活剂。我们提出的研究采用六步优化迭代循环对这类新型复活剂进行了优化，包括在缓冲介质、体外人血和小鼠动物模型中对肟类*BChE催化清除剂体系的复活和OP水解性进行了详细的动力学表征。初步研究结果表明，BChE与优化的肟复活剂相结合，在几分钟的时间内应能在暴露于比LD50 OP剂量高一个数量级的数量级后，在血浆空间中完全和快速地水解OP，而成本仅为目前开发的基于BChE的化学计量清除剂系统的一小部分。因此，拟议的优化催化清除剂系统技术将能够有效地治疗大量OP中毒人群，并对在封闭通风系统中使用OP神经毒剂作为恐怖分子或作战武器起到威慑作用。 公共卫生意义：该项目将开发优化的、高效的和负担得起的丁酰胆碱酯酶催化清除剂系统，用于快速降解暴露于OP制剂的患者血浆空间中的毒物。

DESCRIPTION (provided by applicant): The principal aim of this study is to optimize the efficient and affordable butyrylcholinesterase (BChE) based catalytic scavenger system developed in vitro for treatment of acute organophosphate (OP) intoxication. Currently used oxime and atropine combination therapy is inefficient for treatment of higher exposure OP poisoning due to constant acetylcholinesterase (AChE) reinhibition by excess OP. Novel approaches in therapy based on BChE as stoichiometric scavenger appear prohibitively expensive with a four figure price tag per single application. Conversion of BChE from stoichiometric to catalytic scavenger by combining it with an oxime reactivator has been hampered by lack of efficient BChE reactivators. In our preliminary studies we were able to identify a novel class of superior specific BChE reactivators of distinct nontraditional structural scaffold. Our proposed study deals with optimization of this novel class of reactivators using six step optimization iterative cycle that include detailed kinetic characterization of both reactivation and OP hydrolytic properties of oxime*BChE catalytic scavenger systems in buffer medium, extracorporeal human blood and in vivo in mouse animal model. Results of preliminary studies indicate that BChE in combination with optimized oxime reactivators should completely and rapidly, in a several minute timeframe, hydrolyze OPs in plasma space following exposure to an order of magnitude higher then LD50 OP doses at a fraction of cost of currently developed BChE based stoichiometric scavenger system. The proposed optimized catalytic scavenger system technology will thus enable an effective treatment of large OP intoxicated populations and serve as deterrent to the use of OP based nerve agents as terrorist or combat weapons in closed ventilation systems. PUBLIC HEALTH RELEVANCE: This project will develop optimized, efficient and affordable butyrylcholinesterase based catalytic scavenger system for rapid degradation of toxicants in the plasma space of patients exposed to OP agents.