Evaluation in Primates of Cocaine Esterase for the Treatment of Cocaine Toxicity

描述（由申请人提供）：可卡因酯酶（CocE）是生长在南美洲古柯植物根际的红球菌属细菌的产物。这种细菌利用CocE分解可卡因，作为碳和氮的唯一来源。CocE是迄今所观察到的最有效的可卡因酯酶。我们在啮齿类动物的体内和体外都进行了研究，发现它能够立即逆转这些动物体内致命剂量可卡因的影响。虽然CocE似乎是治疗可卡因过量的极好方法，但由于半衰期很短，它作为治疗可卡因滥用的有用性受到限制。一项资助基金（DA021416）目前正在开发具有更大热稳定性和更长的作用持续时间的CocE突变体，并在可卡因毒性的啮齿动物模型中进行测试。当前应用的目的是评估非人类灵长类动物的天然CocE，作为使这种酶可用于治疗人类可卡因过量过程中的一个步骤。该项目每年将评估一个版本的CocE，从天然酶开始，然后进行突变，这些突变已被证明具有更长的作用持续时间。每年将对每种酶依次进行三种类型的研究。第一项研究将确定这种酶的有效剂量，以减少可卡因对心血管的影响，并清除恒河猴血浆中的一系列剂量的可卡因。第二项研究将侧重于测量对每种酶的免疫反应，当它以一段时间间隔重复施用时，应该最大限度地提高滴度。在此过程中，还将研究CocE滴度发展对酶降低可卡因作用能力的影响。第三项研究包括确定CocE及其长效突变体防止可卡因强化作用和改变自用可卡因对心血管的影响的能力。将反复获得每种酶的剂量-反应函数，并分析血液样本的滴度发展，以便监测对CocE影响的耐受性。

DESCRIPTION (provided by applicant): Cocaine esterase (CocE) is a product of the bacterium Rhodococcus sp. which grows in the rhizospheres of coca plants in South America. The bacterium uses CocE to break down cocaine to provide its sole source of carbon and nitrogen. CocE is the most efficient cocaine esterase yet observed. We have studied it in vitro and in vivo in rodents and found that it is able to reverse immediately the effects of lethal doses of cocaine in these animals. Although CocE appears to be a superb treatment for cocaine overdose, its usefulness as a treatment for cocaine abuse is limited by its very short half life. A funded grant (DA021416) is currently developing mutants of CocE that have greater thermostability and longer durations of action and testing them in rodent models of cocaine toxicity. The purpose of the current application is to evaluate native CocE in non-human primates as a step in the process of making this enzyme available for treatment of cocaine overdose in humans. Each year of the project will evaluate a single version of CocE, starting with the native enzyme, and proceeding through mutants that have been shown to have substantially longer durations of action. Three types of studies will be conducted sequentially in each year with each enzyme. The first will identify effective doses of the enzyme for reducing the cardiovascular effects of cocaine and clearing a range of doses of cocaine from the plasma of rhesus monkeys. The second study will focus on measuring immunological responses to each enzyme when it is administered repeatedly at intervals that should maximize development of titers. The effect of CocE titer development on the ability of the enzyme to reduce the effects of cocaine will also be studied in this process. The third study involves determination of the ability of CocE and its longer-acting mutants to prevent the reinforcing effects of cocaine and to modify the cardiovascular effects of self-administered cocaine. Dose-response functions for each enzyme will be obtained repeatedly and blood samples analyzed for titer development so that tolerance to the effects of CocE can be monitored.