Lamotrigine effects on immune gene expression in larval zebrafish.

PURPOSE: Despite growing evidence that neuroinflammation and pro-inflammatory cytokines are involved in the pathogenesis of seizures and epilepsy, this knowledge has not been incorporated in the proposed mechanism of action of any of the current antiseizure medications (ASMs). Here, we tested the hypothesis by assessing inflammation markers in larval zebrafish (Danio rerio) exposed to lamotrigine (LTG). METHODS: In order to establish the most appropriate LTG concentrations for the transcriptome analysis (RNAseq), we initially assessed for teratogenic (spinal cord deformation, heart oedema, failed inflation of the swim bladder) and behavioural effects (distance moved, time spent active, and average swimming speed during a light/dark test) in zebrafish larvae exposed to 0, 50, 100, 300, 500, 750, and 1000 µM LTG continuously between 5 and 120 h post fertilisation. Subsequently, we repeated the experiment with 0, 50, 100, or 300 µM LTG for transcriptomic analyses. Two databases (Kyoto Encyclopedia of Genes and Genomes; Gene Ontology) were used to interpret changes in gene expression between groups. RESULTS: Major teratogenic effects were observed at concentrations of ≥ 500 µM LTG, whereas behavioural changes were observed at ≥ 300 µM LTG. Transcriptome analysis revealed a non-linear response to LTG. From the suite of differentially expressed genes (DEG), 85% (n = 80 DEGs) were upregulated following exposure to 50 µM LTG, whereas 58% (n = 12 DEGs) and 91% (n = 210 DEGs) were downregulated in response to 100 and 300 µM LTG. The metabolic pathways affected following exposure to 50 and 300 µM LTG were associated with responses to inflammation and pathogens as well development and regulation of the immune system in both groups. Notable genes within the lists of DEGs included component complement 3 (C3.a), which was significantly upregulated in response to 50 µM LTG, whereas interleukin 1ß (IL-1ß) was significantly downregulated in the 300 µM LTG group. The lowest exposure of 50 µM LTG is regarded as clinically relevant to therapeutic exposure. CONCLUSION: We demonstrated that LTG had an impact on the immune system, with a non-monotonic response curve. This dose-dependent relation could indicate that LTG can affect inflammatory responses and also at clinically relevant concentration. Further studies are needed to establish this method as a tool for screening the effects of ASMs on the immune system.

Seizure control after late introduction of anakinra in a patient with adult onset Rasmussen's encephalitis.

Neuroinflammation has been considered an important pathophysiological process involved in epileptogenesis and may provide possibilities for new treatment possibilities. We present the case of a 45-year-old female with drug resistant epilepsy and progressive right-sided cerebral hemiatrophy associated with adult onset Rasmussen's encephalitis. Over a period of 26 years, she was treated with 14 different antiseizure medications, intravenous immunoglobulins, glucocorticosteroids, underwent two operations with focal resection and subpial transections, and tried out trigeminal nerve stimulation. Extensive blood tests, including antibodies relevant for autoimmune encephalitis, and brain biopsy did not show any signs of neuroinflammation. Eventually, the patient received the interleukin-1 receptor antagonist, anakinra. Within 1-2 days after injection, seizure frequency decreased significantly, and, after one week, the seizures stopped completely. Anakinra treatment was continued for 2 months. Stopping medication led to a relapse of seizures after 2 weeks, with a frequency of up to 45 seizures per day. Reintroduction of anakinra led to rapid recovery. Treatment with anakinra was continued for 7 months. The treatment was discontinued in April 2020, and the patient has been completely seizure free since then. There have been no other changes in antiseizure medication.

Interleukin 18 (IL-18) and its binding protein (IL-18BP) are increased in patients with epilepsy suggesting low-grade systemic inflammation.

PURPOSE: Proinflammatory cytokines seems to play a role in epileptogenesis independent of the underlying cause. The purpose of this study was to assess if IL-18 and its binding protein IL-18BP are related to epilepsy and could act as a predictive biomarker for epileptogenesis. METHODS: In this cross-sectional study, circulating levels of IL-18 and IL-18BP were analysed in 119 epilepsy patients, and 80 healthy controls. Participants completed a questionnaire regarding epilepsy, use of drug(-s) and comorbidity. RESULTS: Epilepsy patients had significantly higher serum levels of IL-18 (p = 0.003) and IL-18BP (p = 0.009) than healthy controls. The groups differed in sex, age and weight, however none of those variables were significantly correlated with IL-18 and IL-18BP in patients or controls. Weight was considered an important confounder in our study. Subgroup investigations revealed that in participants with BMI under 30 kg/m², serum IL-18 (p = 0.032) and IL-18BP (p = 0.029) remained significantly higher in patients than controls. Further analyses showed significantly higher concentration of IL-18 among participants using carbamazepine (CBZ) (p = 0.016) or lamotrigine (LTG) (p = 0.024), but not in those using levetiracetam (LEV) (p = 0.102) compared to controls. No associations were found between serum levels of IL-18 and IL-18BP and epilepsy duration, seizures type, or presence of seizures in the last six months. CONCLUSION: The study shows an elevation of IL-18 and IL-18BP serum levels in epilepsy patients. This result indicates the presence of a low-grade systemic inflammation involving IL-18 in epilepsy. Further investigations should explore the character and clinical impact of IL-18 as well its possible role as a biomarker for epilepsy.

Interactions between antiepileptic drugs and hormones.

Antiepileptic drugs (AEDs) are known to have endocrine side effects in both men and women. These can affect fertility, sexuality, thyroid function, and bone health, all functions of major importance for well-being and quality of life. The liver enzyme inducing antiepileptic drugs (EIAEDs), like phenobarbital, phenytoin, and carbamazepine, and also valproate (VPA), a non-EIAED, are most likely to cause such side effects. AED treatment can alter the levels of different sex hormones. EIAEDs increase sex hormone binding globulin (SHBG) concentrations in both men and women. Over time, this elevation can lead to lower levels of bioactive testosterone and estradiol, which may cause menstrual disturbances, sexual problems, and eventually reduced fertility. VPA can cause weight gain in both men and women. In women, VPA can also lead to androgenization with increased serum testosterone concentrations, menstrual disturbances, and polycystic ovaries. Lamotrigine has not been shown to result in endocrine side effects. The newer AEDs have not yet been thoroughly studied, but case reports indicate that some of these drugs could also be suspected to cause such effects if endocrine changes commence after treatment initiation. It is important to be aware of possible endocrine side effects of AEDs as they can have a major impact on quality of life, and are, at least partly, reversible after AED discontinuation.