Tropomyosin receptor kinase B (TRKB) blockade with Lestaurtinib (CEP-701) to abort status epilepticus and prevent its detrimental behavioral consequences

Abstract

Background: Convulsive status epilepticus (CSE), the most common pediatric neurological emergency is associated with long-term cognitive and psychiatric deficits. To date, no drug has been shown to be effective in preventing these detrimental consequences. In addition, the timely abortion of CSE is critical for the attenuation of its sequelae; however, this condition is resistant to anti-seizure drugs in up to 30% of cases. According to preliminary data in our laboratory, Lestaurtinib (CEP-701) modifies Tropomyosin receptor kinase B (TrkB) activity, increases phenobarbital's anticonvulsant efficacy against Kainic acid (KA)-induced CSE abortion, and inhibits CSE-induced depressive-like behaviors in the KA rat model of temporal lobe epilepsy (TLE). CEP-701 was tested as an adjuvant in a clinical therapy scenario for CSE in children, with the aim of aborting CSE and preventing its detrimental sequelae, namely the cognitive and emotional-behavioral abnormalities, as well as CSE-induced hippocampus neuronal damage.

Methods: In the short-term paradigm, CSE was induced with 0.5μg of intra-amygdalar (i.a.) KA in postnatal day 40 (P40) rats under electroencephalogram (EEG) monitoring. Diazepam (25 mg/kg) was administered 15 minutes post-CSE with either CEP-701 (15 mg/kg) or vehicle (DMSO) intra-peritoneally (i.p.). Another same dose of i.p. diazepam dose was injected 30 minutes post-CSE. A single dose of i.p. levetiracetam (750 mg/kg) was given 45 minutes post-CSE. Controls received intra-amygdalar saline, followed by CEP-701 or vehicle, and all received diazepam and levetiracetam. Rats were sacrificed 24 hors post-CSE, and brains were used for histological and molecular analyses. In the long-term paradigm, CSE was also induced with 0.5μg of intra-amygdalar KA in postnatal day 40 (P40) EEG-monitored rats. 15 minutes post-CSE onset, rats received either CEP-701 (15 mg/kg) or vehicle (DMSO) intraperitoneally (i.p.). Diazepam (50 mg/kg, i.p.) was given 2 hours post-CSE onset. The rats were subjected to 2 days of EEG monitoring post CSE induction and then sequentially subjected to the light dark test followed by open field test then the forced swim test was performed. The Morris water maze was then performed and then finally the modified active avoidance test. Post-behavioral testing, rats were subjected to continuous long-term EEG monitoring for 1 month and then were sacrificed at postnatal day P100 for further histological analyses.

Results: All rats experienced electroclinical seizures reaching Racine stages 4 following KA injections. Short-term outcomes revealed that the CEP-701 treated rats (SKCEP) had a statistically significant shorter seizure duration compared to the vehicle treated rats (SKV) (p<0.05) (SKV: 15.88±1.331 hours versus SKCEP: 8.644 ±1.413 hours). The SKV and SKCEP groups had comparable hippocampal neuronal densities and both were lower than their respective controls. In the long-term paradigm, the small number of rats per group was a limitation for performing statistical analyses, but compared to their control group (LSV), there were trends for the vehicle treated rats (LKV) post-CSE to have increased immobility in the FST test, increased time spent in the periphery in the OFT, and contextual deficits in the MWM and MAAV tests. The CEP-701 treated rats (LKCEP) that underwent CSE, had lower immobility than vehicle treated rats in the FST, and were comparable to controls. CEP-701 treated rats post-CSE were comparable to vehicle treated rats in the rest of the tests.

Conclusion: We show that CEP-701 enhances the anti-seizure effect of standard medications to abort CSE, but does not alleviate CSE-induced hippocampal damage. As far as CSE-induced behavioral sequelae, CEP-701 may reverse the depressive-like behaviors. Further work remains to be done to fully investigate the outcomes of the long-term experimental paradigms by increasing the number of rats per group. Given its human safety profile, CEP-701 is a promising drug to the standard clinical paradigms and can pave the way for future clinical trials, and thus plays a role as an adjuvant anti-seizure medication.