Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA; Epilepsy Therapy Screening Program (ETSP) Contract Site, University of Utah, Salt Lake City, UT 84112, USA; Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84108, USA.
Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA; Epilepsy Therapy Screening Program (ETSP) Contract Site, University of Utah, Salt Lake City, UT 84112, USA.
Exp Neurol. 2022 Mar;349:113954. doi: 10.1016/j.expneurol.2021.113954. Epub 2021 Dec 17.
The discovery and development of novel antiseizure drugs (ASDs) that are effective in controlling pharmacoresistant spontaneous recurrent seizures (SRSs) continues to represent a significant unmet clinical need. The Epilepsy Therapy Screening Program (ETSP) has undertaken efforts to address this need by adopting animal models that represent the salient features of human pharmacoresistant epilepsy and employing these models for preclinical testing of investigational ASDs. One such model that has garnered increased interest in recent years is the mouse variant of the Intra-Amygdala Kainate (IAK) microinjection model of mesial temporal lobe epilepsy (MTLE). In establishing a version of this model, several methodological variables were evaluated for their effect(s) on pertinent quantitative endpoints. Although administration of a benzodiazepine 40 min after kainate (KA) induced status epilepticus (SE) is commonly used to improve survival, data presented here demonstrates similar outcomes (mortality, hippocampal damage, latency periods, and 90-day SRS natural history) between mice given midazolam and those that were not. Using a version of this model that did not interrupt SE with a benzodiazepine, a 90-day natural history study was performed and survival, latency periods, SRS frequencies and durations, and SRS clustering data were quantified. Finally, an important step towards model adoption is to assess the sensitivities or resistances of SRSs to a panel of approved and clinically used ASDs. Accordingly, the following ASDs were evaluated for their effects on SRSs in these mice: phenytoin (20 mg/kg, b.i.d.), carbamazepine (30 mg/kg, t.i.d.), valproate (240 mg/kg, t.i.d.), diazepam (4 mg/kg, b.i.d.), and phenobarbital (25 and 50 mg/kg, b.i.d.). Valproate, diazepam, and phenobarbital significantly attenuated SRS frequency relative to vehicle controls at doses devoid of observable adverse behavioral effects. Only diazepam significantly increased seizure freedom. Neither phenytoin nor carbamazepine significantly altered SRS frequency or freedom under these experimental conditions. These data demonstrate that SRSs in this IAK model of MTLE are pharmacoresistant to two representative sodium channel-inhibiting ASDs (phenytoin and carbamazepine) and partially sensitive to GABA receptor modulating ASDs (diazepam and phenobarbital) or a mixed-mechanism ASD (valproate). Accordingly, this model is being incorporated into the NINDS-funded ETSP testing platform for treatment resistant epilepsy.
新型抗癫痫药物(ASD)的发现和开发对于控制耐药性自发性复发性癫痫(SRS)仍然是一个重大的未满足的临床需求。癫痫治疗筛选计划(ETSP)通过采用代表人类耐药性癫痫特征的动物模型并将这些模型用于研究性 ASD 的临床前测试来努力满足这一需求。近年来,一种越来越受到关注的模型是内侧颞叶癫痫(MTLE)的内侧杏仁核海人酸(IAK)微量注射模型的小鼠变体。在建立这种模型的过程中,评估了几个方法变量对相关定量终点的影响。尽管在海人酸(KA)诱导的癫痫持续状态(SE)后 40 分钟给予苯二氮䓬类药物通常用于提高存活率,但这里呈现的数据表明,接受咪达唑仑和未接受咪达唑仑的小鼠之间的死亡率、海马损伤、潜伏期和 90 天 SRS 自然史结果相似。使用一种未用苯二氮䓬类药物中断 SE 的模型版本,进行了 90 天自然史研究,并对存活率、潜伏期、SRS 频率和持续时间以及 SRS 聚类数据进行了量化。最后,向模型采用迈进的重要一步是评估 SRS 对一组批准和临床使用的 ASD 的敏感性或耐药性。因此,评估了以下 ASD 对这些小鼠 SRS 的影响:苯妥英(20mg/kg,bid)、卡马西平(30mg/kg,tid)、丙戊酸钠(240mg/kg,tid)、地西泮(4mg/kg,bid)和苯巴比妥(25 和 50mg/kg,bid)。在没有观察到明显不良行为影响的剂量下,丙戊酸钠、地西泮和苯巴比妥与载体对照相比显著降低了 SRS 频率。只有地西泮显著增加了无癫痫发作的自由。在这些实验条件下,苯妥英或卡马西平均未显著改变 SRS 频率或自由。这些数据表明,内侧杏仁核海人酸模型中的 SRS 对两种代表性的钠通道抑制性 ASD(苯妥英和卡马西平)具有耐药性,对 GABA 受体调节性 ASD(地西泮和苯巴比妥)或混合机制 ASD(丙戊酸钠)具有部分敏感性。因此,该模型正在被纳入 NINDS 资助的 ETSP 治疗耐药性癫痫测试平台。