Tiziana Granata

Brain Inflammation in Epilepsy: Experimental and Clinical Evidence

Summary:  Inflammatory reactions occur in the brain in various CNS diseases, including autoimmune, neurodegenerative, and epileptic disorders. Proinflammatory and antiinflammatory cytokines and related molecules have been described in CNS and plasma, in experimental models of seizures and in clinical cases of epilepsy. Inflammation involves both the innate and the adaptive immune systems and shares molecules and pathways also activated by systemic infection. Experimental studies in rodents show that inflammatory reactions in the brain can enhance neuronal excitability, impair cell survival, and increase the permeability of the blood–brain barrier to blood‐borne molecules and cells. Moreover, some antiinflammatory treatments reduce seizures in experimental models and, in some instances, in clinical cases of epilepsy. However, inflammatory reactions in brain also can be beneficial, depending on the tissue microenvironment, the inflammatory mediators produced in injured tissue, the functional status of the target cells, and the length of time the tissue is exposed to inflammation. We provide an overview of the current knowledge in this field and attempt to bridge experimental and clinical evidence to discuss critically the possibility that inflammation may be a common factor contributing, or predisposing, to the occurrence of seizures and cell death, in various forms of epilepsy of different etiologies. The elucidation of this aspect may open new perspectives for the pharmacologic treatment of seizures.

Seizure‐Promoting Effect of Blood–Brain Barrier Disruption

Summary:  Purpose: It is generally accepted that blood–brain barrier (BBB) failure occurs as a result of CNS diseases, including epilepsy. However, evidences also suggest that BBB failure may be an etiological factor contributing to the development of seizures.

Spectrum of SCN1A mutations in severe myoclonic epilepsy of infancy

Objectives: SCN1A mutations were recently reported in several patients with severe myoclonic epilepsy in infancy (SMEI). The authors analyzed SCN1A mutations in 93 patients with SMEI and made genotype-phenotype correlation to clarify the role of this gene in the etiology of SMEI. Methods: All patients fulfilled the criteria for SMEI. The authors analyzed all patients for SCN1A mutations using denaturing high performance liquid chromatography. If a patient’s chromatogram was abnormal, the authors sequenced the gene in the patient and both parents. Results: SCN1A mutations were identified in 33 patients (35%). Most mutations were de novo, but were inherited in three patients. Parents carrying the inherited mutations had either no symptoms or a milder form of epilepsy. A greater frequency of unilateral motor seizures was the only clinical difference between patients with SCN1A mutations and those without. Truncating mutations were more frequently associated with such seizures than were missense mutations. The percentage of cases with family history of epilepsy was significantly higher in patients with SCN1A mutations. Conclusions: Unilateral motor seizures may be a specific clinical characteristic of SMEI caused by SCN1A mutations. Ten percent of SCN1A mutations are inherited from an asymptomatic or mildly affected parent, suggesting that SMEI is genetically heterogeneous. The increased frequency of familial epilepsy indicates that other genetic factors may contribute to this disorder.

Antagonism of peripheral inflammation reduces the severity of status epilepticus

Status epilepticus (SE) is one of the most serious manifestations of epilepsy. Systemic inflammation and damage of blood-brain barrier (BBB) are etiologic cofactors in the pathogenesis of pilocarpine SE while acute osmotic disruption of the BBB is sufficient to elicit seizures. Whether an inflammatory-vascular-BBB mechanism could apply to the lithium-pilocarpine model is unknown. LiCl facilitated seizures induced by low-dose pilocarpine by activation of circulating T-lymphocytes and mononuclear cells. Serum IL-1beta levels increased and BBB damage occurred concurrently to increased theta EEG activity. These events occurred prior to SE induced by cholinergic exposure. SE was elicited by lithium and pilocarpine irrespective of their sequence of administration supporting a common pathogenetic mechanism. Since IL-1beta is an etiologic trigger for BBB breakdown and its serum elevation occurs before onset of SE early after LiCl and pilocarpine injections, we tested the hypothesis that intravenous administration of IL-1 receptor antagonists (IL-1ra) may prevent pilocarpine-induced seizures. Animals pre-treated with IL-1ra exhibited significant reduction of SE onset and of BBB damage. Our data support the concept of targeting systemic inflammation and BBB for the prevention of status epilepticus.

Familial schizencephaly associated with EMX2 mutation

We describe two brothers aged 8 and 10 affected by severe bilateral schizencephaly, carrying an identical point mutation of the homeobox gene EMX2. Both children had severe neurologic deficits and mental retardation, although they differed in the anatomic extent of the brain malformation and in the severity of the clinical picture. The present findings, together with the reported cases of schizencephaly associated with EMX2 mutations, support the hypothesis that, at least in some cases, schizencephalies are determined by deleterious mutations of this homeobox gene. The different morphoclinical pictures suggest that, besides the EMX2 mutation, other factors are relevant in determining the severity of the brain malformation and clinical picture.

Experience with immunomodulatory treatments in Rasmussen’s encephalitis

The authors investigated immunomodulatory treatments in 15 patients with Rasmussen encephalitis (RE) (14 with childhood and one with adolescent onset RE). Positive time-limited responses were obtained in 11 patients using variable combinations of corticosteroids, apheresis, and high-dose IV immunoglobulins. Although surgical exclusion of the affected hemisphere is the only treatment that halts disease progression, immunomodulation can be considered when early surgery is not feasible, in late-onset patients with slower disease progression, and in the few cases of bilateral disease.

Epileptic phenotypes associated with mitochondrial disorders

Objective: To define the clinical and EEG features of the epileptic syndromes occurring in adult and infantile mitochondrial encephalopathies (ME). Methods: Thirty-one patients with recurrent and apparently unprovoked seizures associated with primary ME were included in the study. Diagnosis of ME was based on the recognition of a morphologic, biochemical, or molecular defect. Results: Epileptic seizures were the first recognized symptom in 53% of the patients. Many adults (43%) and most infants (70%) had nontypical ME phenotypes. Partial seizures, mainly with elementary motor symptoms, and focal or multifocal EEG epileptiform activities characterized the epileptic presentation in 71% of the patients. Generalized myoclonic seizures were an early and consistent symptom only in the five patients with an A8344G mitochondrial DNA point mutation with classic myoclonus epilepsy with ragged red fibers (MERRF) syndrome or “overlapping” characteristics. Photoparoxysmal EEG responses were observed not only in patients with typical MERRF, but also in adult patients with ME with lactic acidosis and strokelike episodes (MELAS), or overlapping phenotypes, and in one child with Leigh syndrome. Conclusions: Epilepsy is an important sign in the early presentation of ME and may be the most apparent neurologic sign of nontypical ME, often leading to the diagnostic workup. Except for those with an A8344G mitochondrial DNA point mutation, most of our patients had partial seizures or EEG signs indicating a focal origin.

Polymicrogyria and deletion 22q11.2 syndrome: window to the etiology of a common cortical malformation.

Several brain malformations have been described in rare patients with the deletion 22q11.2 syndrome (DEL22q11) including agenesis of the corpus callosum, pachygyria or polymicrogyria (PMG), cerebellar anomalies and meningomyelocele, with PMG reported most frequently. In view of our interest in the causes of PMG, we reviewed clinical data including brain‐imaging studies on 21 patients with PMG associated with deletion 22q11.2 and another 11 from the literature. We found that the cortical malformation consists of perisylvian PMG of variable severity and frequent asymmetry with a striking predisposition for the right hemisphere (P = 0.008). This and other observations suggest that the PMG may be a sequela of abnormal embryonic vascular development rather than a primary brain malformation. We also noted mild cerebellar hypoplasia or mega‐cisterna magna in 8 of 24 patients. Although this was not the focus of the present study, mild cerebellar anomalies are probably the most common brain malformation associated with DEL22q11.

An open-label trial of levetiracetam in severe myoclonic epilepsy of infancy

Objective: To conduct an open-label, add-on trial on safety and efficacy of levetiracetam in severe myoclonic epilepsy of infancy (SMEI). Patients and Methods: SMEI patients were recruited from different centers according to the following criteria: age ≥3 years; at least four tonic-clonic seizures/month during the last 8 weeks; previous use of at least two drugs. Levetiracetam was orally administrated at starting dose of approximately 10 mg/kg/day up to 50 to 60 mg/kg/day in two doses. Treatment period included a 5- to 6-week up-titration phase and a 12-week evaluation phase. Efficacy variables were responder rate by seizure type and reduction of the mean number per week of each seizure type. Analysis was performed using Fisher exact and Wilcoxon tests. Results: Twenty-eight patients (mean age: 9.4 ± 5.6 years) entered the study. Sixteen (57.1%) showed SCN1A mutations. Mean number of concomitant drugs was 2.5. Mean levetiracetam dose achieved was 2,016 mg/day. Twenty-three (82.1%) completed the trial. Responders were 64.2% for tonic-clonic, 60% for myoclonic, 60% for focal, and 44.4% for absence seizures. Number per week of tonic-clonic (median: 3 vs 1; p = 0.0001), myoclonic (median: 21 vs 3; p = 0.002), and focal seizures (median: 7.5 vs 3; p = 0.031) was significantly decreased compared to baseline. Levetiracetam effect was not related to age at onset and duration of epilepsy, genetic status, and concomitant therapy. Levetiracetam was well tolerated by subjects who completed the study. To date, follow-up ranges 6 to 36 months (mean, 16.2 ± 13.4). Conclusion: Levetiracetam add-on is effective and well tolerated in severe myoclonic epilepsy of infancy. Placebo-controlled studies should confirm these findings.

Rasmussen's encephalitis: Early characteristics allow diagnosis

Objective: To identify early manifestations of Rasmussen encephalitis (RE) that can prompt early and reasonably secure diagnosis, allowing medical or surgical therapies at an early stage when they may be more effective in slowing the disease. Methods: The authors studied 12 patients with clinical and neuropathologic diagnosis of RE, followed from disease onset, assessing clinical history, imaging, and EEG and focusing on early characteristics. Anti-GluR3 antibody assays were also considered in 11 patients. Results: By 4 months from first symptoms, all cases had 1) refractory focal seizures with a predominant motor component, 2) slow focal activity on EEG contralateral to the motor manifestations, and 3) focal contralateral white matter hyperintensity with insular cortical atrophy on neuroimaging. Less constant or later findings were epilepsia partialis continua, oligoclonal bands, and serum anti-GluR3 antibodies. Conclusions: The association of partial seizures with focal EEG and neuroimaging changes allows a tentative diagnosis of RE 4 to 6 months after first symptoms.