Model Of Infantile Spasms Research Articles

2-deoxyglucose and β-hydroxybutyrate fail to attenuate seizures in the betamethasone-NMDA model of infantile spasms.

Infantile spasms (IS) is an epileptic encephalopathy with a poor neurodevelopmental prognosis, and limited, often ineffective treatment options. The effectiveness of metabolic approaches to seizure control is being increasingly shown in a wide variety of epilepsies. This study investigates the efficacy of the glycolysis inhibitor 2‐deoxyglucose (2‐DG) and the ketone body β‐hydroxybutyrate (BHB) in the betamethasone‐NMDA model of rat IS. Prenatal rats were exposed to betamethasone on gestational day 15 (G15) and NMDA on postnatal day 15 (P15). Video‐electroencephalography (v‐EEG) was used to monitor spasms. NMDA consistently induced hyperflexion spasms associated with interictal sharp‐slow wave EEG activity and ictal flattening of EEG signals, reminiscent of hypsarrhythmia and electrodecrement, respectively. 2‐DG (500 mg/kg, i.p), BHB (200 mg/kg, i.p.), or both were administered immediately after occurrence of the first spasm. No experimental treatment altered significantly the number, severity, or progression of spasms compared with saline treatment. These data suggest that metabolic inhibition of glycolysis or ketogenesis does not reduce infantile spasms in the NMDA model. The study further validates the betamethasone‐NMDA model in terms of its behavioral and electrographic resemblance to human IS and supports its use for preclinical drug screening.

New developments for dietary treatment of epilepsy after a century of history for the ketogenic diet.

This scientific commentary refers to ‘The link between brain acidosis, breathing, and seizures: a novel mechanism of action for the ketogenic diet in a model of infantile spasms’ by Choudhary et al. (https://doi.org/10.1093/braincomms/fcab189) and ‘K.Vita: a feasibility study of a blend of medium chain triglycerides to manage drug-resistant epilepsy’ by Schoeler et al. (https://doi.org/10.1093/braincomms/fcab160)

The link between brain acidosis, breathing and seizures: a novel mechanism of action for the ketogenic diet in a model of infantile spasms.

Infantile spasms (IS) syndrome is a catastrophic, epileptic encephalopathy of infancy that is often refractory to current antiepileptic therapies. The ketogenic diet (KD) has emerged as an alternative treatment for patients with medically intractable epilepsy, though the prospective validity and mechanism of action for IS remains largely unexplored. We investigated the KD's efficacy as well as its mechanism of action in a rodent model of intractable IS. The spasms were induced using the triple-hit paradigm and the animals were then artificially reared and put on either the KD (4:1 fats: carbohydrate + protein) or a control milk diet (CM; 1.7:1). 31Phosphorus magnetic resonance spectroscopy (31P MRS) and head-out plethysmography were examined in conjunction with continuous video-EEG behavioural recordings in lesioned animals and sham-operated controls. The KD resulted in a peripheral ketosis observed both in the blood and urine. The KD led to a robust reduction in the frequency of spasms observed, with approximately a 1.5-fold increase in the rate of survival. Intriguingly, the KD resulted in an intracerebral acidosis as measured with 31P MRS. In addition, the respiratory profile of the lesioned rats on the KD was significantly altered with slower, deeper and longer breathing, resulting in decreased levels of expired CO2. Sodium bicarbonate supplementation, acting as a pH buffer, partially reversed the KD's protective effects on spasm frequency. There were no differences in the mitochondrial respiratory profiles in the liver and brain frontal cortex measured between the groups, supporting the notion that the effects of the KD on breathing are not entirely due to changes in intermediary metabolism. Together, our results indicate that the KD produces its anticonvulsant effects through changes in respiration leading to intracerebral acidosis. These findings provide a novel understanding of the mechanisms underlying the anti-seizure effects of the KD in IS. Further research is required to determine whether the effects of the KD on breathing and intracerebral acid-base balance are seen in other paediatric models of epilepsy.

ACTON PROLONGATUM® suppresses spasms head to head with Acthar® Gel in the model of infantile spasms

Epileptic spasms during infancy (infantile spasms, IS) are a rare epilepsy syndrome with dire prognosis. Current treatments, effective in about 55% of cases, include hormonal therapy (adrenocorticotropic hormone [ACTH] = adrenocorticotropin or corticosteroids) or vigabatrin (also in combination with hormones). In addition to their limited efficacy, these treatments may also carry serious adverse effects. Thus, the search for new effective drugs to treat this rare disease is desirable. In this study, we determined the efficacy of ACTON PROLONGATUM® (AP; Ferring Pharmaceuticals) in comparison with Acthar® Gel (Mallinckrodt) and full 39 amino-acid rat ACTH molecule (Genscript) in the rodent model of IS consisting of prenatal priming with betamethasone and repeated postnatal trigger of spasms with N-methyl-d-aspartate. Treatment with these ACTH varieties was given on postnatal days (P)12, P13, and P14 in a prospective test (treatment onset on P12 AFTER induction of spasms). Two independent arms were investigated: subcutaneous (SC) and intramuscular (IM) deliveries that were evaluated separately. In the SC arm, there was a significant suppression of the number of spasms after both Acthar® Gel and AP on P13 and P15 compared with gelatin control. In the IM arm, a significant suppression of the number of spasms was achieved only after AP on both P13 and P15 indicating that after IM delivery, Acthar® Gel was not as effective as AP. In this study, we confirmed the efficacy of two ACTH formulations (gelatin-based Acthar® Gel and carboxymethyl cellulose-based AP) in the model of IS. ACTON PROLONGATUM® may become a valuable therapy for IS. In our animal model, AP was at least as efficient as the standard of care, Acthar® Gel.

Acquired parvalbumin-selective interneuronopathy in the multiple-hit model of infantile spasms: A putative basis for the partial responsiveness to vigabatrin analogs?

SummaryWest syndrome, an age‐specific epileptic encephalopathy, manifests with infantile spasms (IS) and impaired neurodevelopmental outcomes and epilepsy. The multiple‐hit rat model of IS is a chronic model of IS due to structural etiology, in which spasms respond partially to vigabatrin analogs. Using this model, we investigated whether IS due to structural etiology may have deficits in parvalbumin (PRV) and somatostatin (SST) immunoreactive (‐ir) interneurons, and calretinin‐ir (CR‐ir) neurons of the primary somatosensory cortex of postnatal day (PN) 20–24 rats, using specific immunohistochemical assays. PN3 Sprague‐Dawley male rats underwent the multiple‐hit induction protocol, were monitored until PN20–24, and were transcardially perfused to collect brains for histology. Age‐matched sham and naive control male rats were also used. Coronal brain cryosections were stained with anti‐PRV, anti‐CR, and anti‐SST antibodies, and regions of interest (ROIs) from the primary somatosensory cortices were selected to determine PRV‐, CR‐, and SST‐ir cell counts and cortical ROI volumes, with blinding to experimental group. Statistical analyses were done using a linear mixed model accounting for repeated measures. We found PRV‐ir interneuronal selective reduction, sparing of the CR‐ir and SST‐ir neurons, and bilateral cortical atrophy. Our findings provide evidence for acquired PRV‐selective interneuronopathy, possibly underlying the pathogenesis of IS, neurodevelopmental deficits, and epilepsy, and potentially contributing to the partial response to vigabatrin analogs in this model.

APC conditional knock-out mouse is a model of infantile spasms with elevated neuronal β-catenin levels, neonatal spasms, and chronic seizures

Infantile spasms (IS) are a catastrophic childhood epilepsy syndrome characterized by flexion-extension spasms during infancy that progress to chronic seizures and cognitive deficits in later life. The molecular causes of IS are poorly defined. Genetic screens of individuals with IS have identified multiple risk genes, several of which are predicted to alter β-catenin pathways. However, evidence linking malfunction of β-catenin pathways and IS is lacking. Here, we show that conditional deletion in mice of the adenomatous polyposis coli gene (APC cKO), the major negative regulator of β-catenin, leads to excessive β-catenin levels and multiple salient features of human IS. Compared with wild-type littermates, neonatal APC cKO mice exhibit flexion-extension motor spasms and abnormal high-amplitude electroencephalographic discharges. Additionally, the frequency of excitatory postsynaptic currents is increased in layer V pyramidal cells, the major output neurons of the cerebral cortex. At adult ages, APC cKOs display spontaneous electroclinical seizures. These data provide the first evidence that malfunctions of APC/β-catenin pathways cause pathophysiological changes consistent with IS. Our findings demonstrate that the APC cKO is a new genetic model of IS, provide novel insights into molecular and functional alterations that can lead to IS, and suggest novel targets for therapeutic intervention.

A potential effect of ganaxolone in an animal model of infantile spasms

Infantile spasms (IS), a devastating epileptic encephalopathy of infancy, involve various etiologies associated with an unknown underlying common pathophysiology. The efficacy of adrenocorticotropic hormone (ACTH) as an IS therapy suggests a role for steroid hormones in treating IS. This study used an animal model of IS to test the efficacy of ganaxolone, a synthetic neurosteroid, promoting tonic GABAA inhibition. The model of cryptogenic IS used in this study involved prenatal priming of rats with betamethasone (0.4 mg/kg i.p. at 08:30 and 18:30) on gestational day 15. To test the acute effects of ganaxolone, rats were pretreated with ganaxolone (10, 25, or 50mg/kg i.p.) or vehicle (β-cyclodextrin, i.p.) 30 min prior to N-methyl-d-aspartate (NMDA)-induced spasms at postnatal day 15 (P15). To mimic human conditions, another group of rats was randomly divided and repeatedly treated with ganaxolone (20mg/kg at 9:00 and 18:00 from P13-15) or vehicle after experiencing NMDA-triggered spasms at P12. Additional spasms were triggered on P13 and P15. We determined latency to the onset of spasms and the total number of spasms per 90-min observation period after the trigger at P15. On P19 and P21, behavioral tests were performed in rats with randomized repeated treatments. The 25mg/kg and 50mg/kg doses of ganaxolone significantly delayed the onset of spasms compared with the controls, and significantly decreased the number of spasms or suppressed their incidence. Ganaxolone had significant side effects in terms of sedation: all animals with the 50mg/kg dose were sleeping during the test. Randomized ganaxolone treatment for 3 days also significantly delayed the onset and decreased the number of spasms triggered by NMDA on P15, and decreased exploratory behavior after multiple NMDA triggered spasms. Ganaxolone significantly suppresses the development of spasms in the rat model of cryptogenic IS. This synthetic neurosteroid active in an animal model of IS might contribute to the current armamentarium to treat human IS.

CPP‐115, a vigabatrin analogue, decreases spasms in the multiple‐hit rat model of infantile spasms

Infantile spasms (IS) have poor outcomes and limited treatment options, including vigabatrin, a γ-aminobutyric acid (GABA) aminotransferase inactivator. Vigabatrin has been associated with retinal toxicity. A high affinity vigabatrin analogue (CPP-115; Catalyst Pharmaceutical Partners, Inc., Coral Gables, FL, U.S.A.) has shown lower risk of retinal toxicity. Here, we test the efficacy of CPP-115 in reducing spasms and its tolerability in the multiple-hit rat model of IS, in which daily vigabatrin reduced spasms for only one day, but was not well tolerated. Male rats were treated with the protocol of the multiple-hit model of IS on postnatal day 3 (PN3). Using a randomized, blinded, vehicle-controlled, dose-response study design, CPP-115 (0.1, 1, or 5 mg/kg intraperitoneally [i.p.]) or vehicle was given daily (PN4-12) or as a single injection (PN7) after spasm onset. Intermittent video- or video-electroencephalography (EEG) monitoring was done. Secondary end points included the following: daily weights, survival, performance on open field activity, surface righting time, and negative geotaxis (PN3-20), horizontal bar (PN13-20), and Barnes maze (PN16-19). Statistics used a linear mixed model of raw or normalized log-transformed data, taking into account the repeated observations on each animal. The lower CPP-115 doses (0.1-1 mg/kg/day, PN4-12) reduced spasms between PN6 and 7 without increasing mortality. CPP-115 at 5 mg/kg/day (PN4-12) reduced spasms earlier (PN5), but was eventually lethal. A single CPP-115 injection (1 mg/kg, i.p.) decreased electroclinical spasms acutely but transiently. CPP-115 transiently improved the probability to >50% reduction of spasms, but did not accelerate spasm cessation. CPP-115 did not alter neurodevelopmental outcomes or visuospatial learning. We provide proof-of-concept evidence that CPP-115, a vigabatrin analogue, decreases spasms in the multiple-hit rat model of IS at considerably lower and better tolerated doses than vigabatrin did in our previous studies. Further optimization of the treatment protocol is needed. CPP-115 may be a promising new candidate treatment for IS with better tolerability than vigabatrin.

Validation of the rat model of cryptogenic infantile spasms

To determine whether a new model of cryptogenic infantile spasms consisting of prenatal priming with betamethasone and postnatal trigger of spasms by N-methyl-D-aspartate (NMDA) responds to chronic adrenocorticotropic hormone (ACTH) treatment, and has electroencephalography (EEG) signature, efficacy of treatments, and behavioral impairments similar to those in human infantile spasms. Rats prenatally primed with betamethasone on gestational day 15 were used. Spasms were triggered with NMDA between postnatal days (P) 10 and 15 in a single session or in multiple sessions in one subject. The expression of spasms was compared to prenatally saline-injected controls. Effects of relevant treatments (ACTH, vigabatrin, methylprednisolone, rapamycin) were determined in betamethasone-primed rats. In the rats after spasms, behavioral evaluation was performed in the open field and elevated plus maze on P20-22. NMDA at P10-15 (the rat "infant" period) triggers the spasms significantly earlier and in greater numbers in the prenatal betamethasone-exposed brain compared to controls. Similar to human condition, the spasms occur in clusters. Repeated trigger of spasms is associated with ictal EEG electrodecrements and interictal large-amplitude waves, a possible rat variant of hypsarrhythmia. Chronic ACTH treatment in a randomized experiment, and chronic pretreatment with methylprednisolone significantly suppress the number of spasms similar to the human condition. Pretreatment with vigabatrin, but not rapamycin, suppressed the spasms. Significant behavioral changes occurred following multiple bouts of spasms. The model of infantile spasms has remarkable similarities with the human condition in semiology, EEG, pharmacologic response, and long-term outcome. Therefore, the model can be used to search for novel and more effective treatments for infantile spasms.

Infantile spasms: Toward a selective diagnostic and therapeutic approach

Infantile spasms: Toward a selective diagnostic and therapeutic approach

Model of cryptogenic infantile spasms after prenatal corticosteroid priming

Infantile spasms (IS) is a devastating epilepsy syndrome of childhood. IS occurs in 3-12-month-old infants and is characterized by spasms, interictal electroencephalography (EEG) hypsarrhythmia, and profound mental retardation. Hormonal therapy [adrenocorticotropic hormone (ACTH), corticosteroids] is frequently used, but its efficacy is tainted by severe side effects. For research of novel therapies, a validated animal model of IS is required. We propose the model of spastic seizures triggered by N-methyl-d-aspartate (NMDA) in infant rats prenatally exposed to betamethasone. The spasms have remarkable similarity to human IS, including motor flexion spasms, ictal EEG electrodecrement, and responsiveness to ACTH. Interestingly, the spasms do not involve the hippocampus. Autoradiographic metabolic mapping as well as tagging of the areas of neuronal excitation with c-fos indicates a strong involvement of hypothalamic structures such as the arcuate nucleus, which has significant bilateral connections with other hypothalamic nuclei as well as with the brainstem.

Animal Models of Infantile Spasms: Is the Holy Grail Finally in Sight?

A New Animal Model of Infantile Spasms with Unprovoked Persistent Seizures. Lee CL, Frost JD Jr, Swann JW, Hrachovy RA. Epilepsia 2008;49(2):298–307. PURPOSE: Infantile spasms is one of the most severe epileptic syndromes of infancy and early childhood. Progress toward understanding the pathophysiology of this disorder and the development of effective therapies has been hindered by the lack of a relevant animal model. We report here the creation of such a model. METHODS: The sodium channel blocker, tetrodotoxin (TTX), was chronically infused into the developing neocortex or hippocampus of infant rats by way of an osmotic minipump starting on postnatal day 10–12. RESULTS: After a minimum of 10 days of infusion, approximately one-third of these rats began to display very brief (1–2 s) spasms, which consisted of symmetric or asymmetric flexion or extension of the trunk and sometimes involvement of one or both forelimbs. The typical ictal EEG pattern associated with the behavioral spasms consisted of an initial generalized, high amplitude, slow wave followed by an electrodecrement with superimposed fast activity. The interictal EEG revealed multifocal spikes and sharp waves, and in most animals that had spasms a hypsarrhythmic pattern was seen, at least intermittently, during NREM sleep. Like in humans, the spasms in the rat often occurred in clusters especially during sleep–wake transitions. Comparison of the ictal and interictal EEGs recorded in this model and those from humans with infantile spasms revealed that the patterns and the frequency components of both the ictal events and hypsarrhythmia were very similar. DISCUSSION: The TTX model of infantile spasms should be of value in furthering an understanding of the pathophysiology of this seizure disorder.

Chronic ACTH treatment: Influence on 5-HT2 receptors and behavioral supersensitivity induced by 5,7-dihydroxytryptamine lesions

The capacity of the serotonin (5-HT) precursor 5-HIP to induce the ACTH-responsive myoclonic-convulsive disorder infantile spasms in patients with Down's syndrome has been cited as evidence for altered serotonergic neurotransmission in infantile spasms. Since there is no animal model of infantile spasms, the suitability of behavioral supersensitivity (myoclonus) evoked by 5-HTP in rats with 5,7-dihydroxytryptamine (DHT) lesions as a model was tested by determining the effect of chronic treatment with ACTH (40 IU/kg) on 5-HTP-evoked myoclonus. In rats treated with DHT as adults, ACTH administration did not alter the "serotonergic behaviors," such as myoclonus, induced by 30 mg/kg 5-hydroxytryptophan (5-HTP), but induced a small significant increase in Bmax of neocortical 5-HT2 sites of the DHT group, with no change in rats without lesions. In rats treated with DHT as neonates, there was also no significant difference in behaviors evoked by several doses of 5-HTP. These data suggest that ACTH minimally modifies the effects on 5-HT receptors of DHT lesions, but the intracisternal DHT model is not a suitable model for infantile spasms because chronic ACTH was not antimyoclonic.