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West syndrome model: seek and you will find
R Kábová1, S Veresová, L Velísek
1Department of Pathological Physiology, Third Faculty of Medicine, Charles University Prague, Czech Republic.
Insights
N-methyl-D-aspartate (NMDA)-induced seizures in infant rats mimic some aspects of West syndrome but are resistant to common therapies. This suggests NMDA-induced seizures may not be an accurate model for developing new West syndrome treatments.
Area of Science:
- Neuroscience
- Pediatric Neurology
- Pharmacology
Background:
- West syndrome is an infant-onset epileptic encephalopathy characterized by infantile spasms, hypsarrhythmia on EEG, and developmental delay.
- Current treatments for West syndrome, including ACTH, corticosteroids, valproic acid, pyridoxine, and vigabatrine, are often difficult and necessitate the development of more effective antiepileptic drugs.
- A significant challenge in West syndrome research is the lack of an accurate animal model that fully replicates the human condition.
Purpose of the Study:
- To evaluate the utility of N-methyl-D-aspartate (NMDA)-induced seizures in infant rats as a potential animal model for West syndrome.
- To assess the efficacy of hydrocortisone, pyridoxine, and sodium valproate in treating NMDA-induced seizures in infant rats.
Main Methods:
- Infant rats (12 and 18 days old) were administered NMDA (15 or 45 mg/kg) to induce seizures characterized by hyperflexion (emprosthotonus).
- The effects of hydrocortisone, pyridoxine, and sodium valproate on NMDA-induced seizures and associated neuronal damage were investigated.
- Electroencephalogram (EEG) patterns were monitored, though they were not specific to the induced seizures.
Main Results:
- NMDA-induced seizures in infant rats exhibited age-specificity and hyperflexion, partially resembling West syndrome features.
- Sodium valproate showed minimal efficacy against NMDA-induced emprosthotonus.
- High doses of pyridoxine acted as a proconvulsant, while hydrocortisone exacerbated NMDA-induced neuronal damage.
Conclusions:
- NMDA-induced seizures in infant rats, despite some similarities to West syndrome, demonstrate significant resistance to tested therapies, questioning their suitability as a preclinical model.
- Further research is needed to identify and develop accurate animal models for West syndrome to facilitate the discovery of novel antiepileptic drugs and understand disease mechanisms.
Abstract:
West syndrome is an age-specific epileptic syndrome with onset in infancy. It comprises infantile spasms (usually flexion convulsions), EEG pattern of hypsarrhythmia and mental retardation. Current therapy involves ACTH, corticosteroids, valproic acid, pyridoxine and vigabatrine. The treatment is difficult and more effective antiepileptic drugs are required. Unfortunately, there is no animal model of West syndrome that would accurately depict the situation found in humans. N-methyl-D-asparate (NMDA)-induced seizures in infant rats have certain features of the West syndrome model. These seizures are age-specific (they occur before 25 days of age), include hyperflection (emprosthotonus), their EEG is not specific and they somewhat respond to treatment with the benzodiazepine clonazepam. In 12 and 18 day old rats, we tested the effects of hydrocortisone, pyridoxine and sodium valproate against the seizures induced by 15 and 45 mg/kg of NMDA i.p., respectively. There were weak effects of sodium valproate against the NMDA-induced emprosthotonus. In contrast, high doses of pyridoxine were proconvulsant and hydrocortisone worsened the damage of nerve cells induced by NMDA. The data show that NMDA-induced seizures although similar to West syndrome are extremely resistant to therapy and may not be a good model of the West syndrome. However, the search for an adequate model that would allow for determination of possible mechanisms and testing of putative antiepileptic drugs will continue.