Long-term protective effects of lamotrigine in a rat ovarian ischemia-reperfusion model.

Ovarium torsion is a gynecological emergency that is common in women of reproductive age and requires early diagnosis and intervention. In this study, we aimed to investigate the long-term anatomical, histological and biochemical protective effects of lamotrigine in ovariums in the ischemia - reperfusion (I-R) model created experimentally in rats. A total of 40 female Sprague-Dawley rats, 14 weeks old, weighing 220-270 g were used in the study. The subjects were randomly distributed to form 4 groups named SHAM group, I - R group, I - R + Lamotrigine (LTG) group and R + LTG group. Under general anesthesia, the ovaries of the rats were reached and ischemia was created for 3 h with vascular clamps. 20 mg / kg LTG was administered intraperitoneally (ip.) to group 3 30 min before ischemia and to group 4 30 min before reperfusion. At the third hour of ischemia, the vascular clamps were opened and the abdomen of the rats was closed according to the surgical procedure. The rats were followed up for 28 days postoperatively and the ovarium tissues taken on the 28th day were examined anatomically and histologically. Biochemically, estradiol (E2), follicle stimulating hormone (FSH) and antimullerian hormone (AMH) levels were measured from blood samples taken from their hearts. Granulosa cells with diffuse vaculations were observed in degenerative follicles in group I-R. Again in this group, severe hemorrhage, fibrosis and edematous areas were observed in the ovarium stroma (Ovarian Histopathological Scoring (OHS): 7). In the I - R + LTG group, OHS was statistically significantly lower than the I - R group (OHS: 2; p < 0.000). In the R + LTG group, although the OHS score was calculated to be lower than the I - R group, there was no statistically significant difference (OHS: 6; p > 0.05). The protective effect of LTG against experimentally created ischemia and reperfusion damage was determined anatomically and histologically. No protective effect of LTG was observed in terms of FSH, E2 and AMH values measured from the blood sera of rats. These findings may provide a basis for future studies using LTG to treat ovarian ischemia-reperfusion injury.

Curcumin protects against lamotrigine-induced chronic ovarian and uterine toxicity in rats by regulating PPAR-γ and ROS production.

Lamotrigine (LTG) is an antiepileptic drug with possible adverse effects on the female reproductive system. Curcumin was declared to improve ovarian performance. Therefore, this study aimed to clarify ovulatory dysfunction (OD) associated with LTG and the role of curcumin in ameliorating this dysfunction. Adult female Wister albino rats were assigned into four groups: negative control (received saline), positive control (received curcumin only), LTG, and LTG with curcumin groups. Drugs were administered for 90 days. The hormonal profile, including testosterone, estrogen, progesterone, luteinizing hormone, and follicle-stimulating hormone, in addition to the lipid profile and glycemic analysis, were tested. Oxidative stress biomarkers analysis in the ovaries and uterus and peroxisome proliferator-activated receptor-γ (PPAR-γ) gene expression were also included. Histopathological examination of ovarian and uterine tissues and immunohistochemical studies were also performed. Curcumin could improve the OD related to chronic LTG intake. That was proved by the normalization of the hormonal profile, glycemic control, lipidemic status, oxidative stress markers, and PPAR-γ gene expression. The histopathological and immunohistochemical examination of ovarian and uterine tissues revealed an improvement after curcumin administration. The results describe an obvious deterioration in ovarian performance with LTG through the effect on lipidemic status, PPAR-γ gene, and creating an oxidative stress condition in the ovaries of chronic users, with a prominent improvement with curcumin addition to the treatment protocol.

Caffeine and Its Interactions with Antiseizure Medications-Is There a Correlation between Preclinical and Clinical Data?

Experimental studies reveal that caffeine (trimethylxanthine) at subconvulsive doses, distinctly reduced the anticonvulsant activity of numerous antiseizure medications (ASMs) in rodents, oxcarbazepine, tiagabine and lamotrigine being the exceptions. Clinical data based on low numbers of patients support the experimental results by showing that caffeine (ingested in high quantities) may sharply increase seizure frequency, considerably reducing the quality of patients' lives. In contrast, this obviously negative activity of caffeine was not found in clinical studies involving much higher numbers of patients. ASMs vulnerable to caffeine in experimental models of seizures encompass carbamazepine, phenobarbital, phenytoin, valproate, gabapentin, levetiracetam, pregabalin and topiramate. An inhibition of R-calcium channels by lamotrigine and oxcarbazepine may account for their resistance to the trimethylxanthine. This assumption, however, is complicated by the fact that topiramate also seems to be a blocker of R-calcium channels. A question arises why large clinical studies failed to confirm the results of experimental and case-report studies. A possibility exists that the proportion of patients taking ASMs resistant to caffeine may be significant and such patients may be sufficiently protected against the negative activity of caffeine.

Dual-pocket inhibition of Nav channels by the antiepileptic drug lamotrigine.

Voltage-gated sodium (Nav) channels govern membrane excitability, thus setting the foundation for various physiological and neuronal processes. Nav channels serve as the primary targets for several classes of widely used and investigational drugs, including local anesthetics, antiepileptic drugs, antiarrhythmics, and analgesics. In this study, we present cryogenic electron microscopy (cryo-EM) structures of human Nav1.7 bound to two clinical drugs, riluzole (RLZ) and lamotrigine (LTG), at resolutions of 2.9 Å and 2.7 Å, respectively. A 3D EM reconstruction of ligand-free Nav1.7 was also obtained at 2.1 Å resolution. RLZ resides in the central cavity of the pore domain and is coordinated by residues from repeats III and IV. Whereas one LTG molecule also binds to the central cavity, the other is found beneath the intracellular gate, known as site BIG. Therefore, LTG, similar to lacosamide and cannabidiol, blocks Nav channels via a dual-pocket mechanism. These structures, complemented with docking and mutational analyses, also explain the structure-activity relationships of the LTG-related linear 6,6 series that have been developed for improved efficacy and subtype specificity on different Nav channels. Our findings reveal the molecular basis for these drugs' mechanism of action and will aid the development of novel antiepileptic and pain-relieving drugs.

Lamotrigine compromises the fidelity of initiator tRNA recruitment to the ribosomal P-site by IF2 and the RbfA release from 30S ribosomes in Escherichia coli.

Lamotrigine (Ltg), an anticonvulsant drug, targets initiation factor 2 (IF2), compromises ribosome biogenesis and causes toxicity to Escherichia coli. However, our understanding of Ltg toxicity in E. coli remains unclear. While our in vitro assays reveal no effects of Ltg on the ribosome-dependent GTPase activity of IF2 or its role in initiation as measured by dipeptide formation in a fast kinetics assay, the in vivo experiments show that Ltg causes accumulation of the 17S precursor of 16S rRNA and leads to a decrease in polysome levels in E. coli. IF2 overexpression in E. coli increases Ltg toxicity. However, the overexpression of initiator tRNA (i-tRNA) protects it from the Ltg toxicity. The depletion of i-tRNA or overexpression of its 3GC mutant (lacking the characteristic 3GC base pairs in anticodon stem) enhances Ltg toxicity, and this enhancement in toxicity is synthetic with IF2 overexpression. The Ltg treatment itself causes a detectable increase in IF2 levels in E. coli and allows initiation with an elongator tRNA, suggesting compromise in the fidelity/specificity of IF2 function. Also, Ltg causes increased accumulation of ribosome-binding factor A (RbfA) on 30S ribosomal subunit. Based on our genetic and biochemical investigations, we show that Ltg compromises the function of i-tRNA/IF2 complex in ribosome maturation.

Region- and time- specific effects of ketamine on cerebral blood flow: a randomized controlled trial.

There is intriguing evidence suggesting that ketamine might have distinct acute and delayed neurofunctional effects, as its acute administration transiently induces schizophrenia-like symptoms, while antidepressant effects slowly emerge and are most pronounced 24 h after administration. Studies attempting to characterize ketamine's mechanism of action by using blood oxygen level dependent (BOLD) imaging have yielded inconsistent results regarding implicated brain regions and direction of effects. This may be due to intrinsic properties of the BOLD contrast, while cerebral blood flow (CBF), as measured with arterial spin labeling, is a single physiological marker more directly related to neural activity. As effects of acute ketamine challenge are sensitive to modulation by pretreatment with lamotrigine, which inhibits glutamate release, a combination of these approaches should be particularly suited to offer novel insights. In total, 75 healthy participants were investigated in a double blind, placebo-controlled, randomized, parallel-group study and underwent two scanning sessions (acute/post 24 h.). Acute ketamine administration was associated with higher perfusion in interior frontal gyrus (IFG) and dorsolateral prefrontal cortex (DLPFC), but no other investigated brain region. Inhibition of glutamate release by pretreatment with lamotrigine abolished ketamine's effect on perfusion. At the delayed time point, pretreatment with lamotrigine was associated with lower perfusion in IFG. These findings underscore the idea that regionally selective patterns of CBF changes reflect proximate effects of modulated glutamate release on neuronal activity. Furthermore, region- specific sustained effects indicate both a swift restoration of disturbed homeostasis in DLPFC as well changes occurring beyond the immediate effects on glutamate signaling in IFG.

Modulatory Effects of Ketamine and Lamotrigine on Cognition: Emotion Interaction in the Brain.

INTRODUCTION: Cognition and emotion are fundamentally integrated in the brain and mutually contribute to behavior. The relation between working memory (WM) and emotion is particularly suited to investigate cognition-emotion interaction since WM is an essential component of many higher cognitive functions. Ketamine affects not only WM but also has a profound impact on emotional processing. Effects of acute ketamine challenge are sensitive to modulation by pretreatment with lamotrigine, which inhibits glutamate release. Accordingly, a combination of these approaches should be particularly suited to investigate cognition-emotion interaction. METHODS: Seventy five healthy subjects were investigated in a double-blind, placebo-controlled, randomized, single-dose, parallel-group study with three treatment conditions. All subjects underwent two scanning sessions (acute/post 24 h). RESULTS: Compared to placebo, acute ketamine administration induced significant dissociative, psychotomimetic, and cognitive effects, as well as an increase in neural activity during WM for positive stimuli. Inhibition of glutamate release by pretreatment with lamotrigine did not influence ketamine's subjective effects, but significantly attenuated its impact on emotional WM and associated neural activity. There was no effect on these measures 24 h after ketamine administration. CONCLUSION: Our results demonstrate differential acute effects of modulated glutamate release and a swift restoration of disturbed neurobehavioral homeostasis in healthy subjects.

Eficacia y seguridad de lacosamida como tratamiento complementario en pacientes pediátricos con epilepsia focal refractaria / Efficacy and safety of lacosamide as adjunctive treatment in pediatric patients with refractory focal epilepsy

ANTECEDENTES: En el marco de la metodología ad hoc para evaluar solicitudes de tecnologías sanitarias, aprobada mediante Resolución de Institución de Evaluación de Tecnologías en Salud e Investigación N° 97-IETSI-ESSALUD-2022, se ha elaborado el presente dictamen que expone la evaluación de la eficacia y seguridad de lacosamida para el tratamiento de pacientes pediátricos con epilepsia focal refractaria. Así, el médico Dr. Edwin Martín Lazo Rivera, especialista en neurología pediátrica del Hospital Nacional Carlos Alberto Seguín Escobedo - Red Asistencial Arequipa y la Dra. Rebeca Fiorella Valdivia Bravo, especialista en pediatría del Hospital Nacional Alberto Sabogal Sologuren de la Red Prestacional Sabogal, siguiendo la Directiva N° 003-IETSI-ESSALUD-2016, enviaron al Instituto de Evaluación de Tecnologías en Salud e Investigación ­ IETSI sus respectivas solicitudes de autorización de uso del producto farmacéutico lacosamida no incluido en el Petitorio Farmacológico de EsSalud. ASPECTOS GENERALES: La epilepsia es una condición del sistema nervioso central caracterizada por crisis epilépticas recurrentes y no provocadas por desencadenantes inmediatos identificables. Así, la crisis epiléptica es aquel acontecimiento transitorio de signos y/o síntomas originados por una actividad neuronal cerebral sincrónica anormal o excesiva, que puede manifestarse por fenómenos sensitivos, motores, sensoriales o autonómicos con o sin pérdida de la conciencia, ya que dependen del área cerebral donde se originan. En ese sentido, las crisis convulsivas se clasifican según tres posibilidades de origen: las de inicio focal, generalizado y desconocido. Las crisis focales, a su vez, se pueden subclasificar en aquellas que tienen pérdida o no de la consciencia, para posteriormente categorizar si los síntomas son motores o no motores. En consecuencia, los especialistas deciden el abordaje terapéutico de los pacientes con epilepsia focal teniendo en cuenta esta clasificación, adicional a la etiología y a las comorbilidades asociadas (Reséndiz-Aparicio et al.,2019, Fisher et al.,2017, INSN.,2020). En todo el mundo, la epilepsia afecta aproximadamente a 65 millones de personas, reportándose una incidencia de la epilepsia de 67,8 por 100 000 habitantes en los países en desarrollo (Mohammadzadeh et al., 2022). En el Perú, se estima que la prevalencia de epilepsia es de 11,9 a 32,1 por cada 1000 personas (Burneo et al., 2017). Asimismo, es conocido que la incidencia de la epilepsia en la población pediátrica es de aproximadamente 0,5 % a 1 % de la población general. Además, algunos estudios sugieren que hasta el 60 % de los pacientes pediátricos con epilepsia presentarán remisión de su condición, mientras que alrededor del 20 % a 30 % de los pacientes con epilepsia serán refractarios al tratamiento médico (Ortiz de la Rosa et al., 2015). METODOLOGÍA: La búsqueda bibliográfica exhaustiva se llevó a cabo con el objetivo de identificar la mejor evidencia disponible sobre la eficacia y seguridad de lacosamida para el tratamiento de pacientes pediátricos con epilepsia focal refractaria a los FAE disponibles en EsSalud. La búsqueda bibliográfica se realizó en las bases de datos PubMed, The Cochrane Library. Web of Science y LILACS. Adicionalmente, se amplió la búsqueda revisando la evidencia generada por grupos internacionales que realizan revisiones sistemáticas (RS), evaluaciones de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC) de: la National Institute for Health and Care Excellence (NICE), la American Academy of Neurology (ANN), la American Epilepsy Society (AES), la Scottish Intercollegiate Guidelines Network (SIGN), la Internacional Database of GRADE Guideline (BIGG), la Canadian Agency for Drugs and Technologies in Health (CADTH), la Comissáo Nacional de Incorporadáo de Tecnologias no Sistema Único de Saúde (CONITEC) y el Ministerio de Salud del Perú (MINSA). Adicionalmente, se realizó una búsqueda manual en las bases el portal de la Base Regional de Informes de Evaluación de Tecnologías en Salud de las Américas (BRISA), y el repositorio institucional de la Dirección General de Medicamentos, Insumos y Drogas (DIGEMID). Finalmente, se realizó una búsqueda en el portal ClinicalTrials.govdel National Institutes of Health (NIH) para identificar ensayos clínicos en desarrollo o que aún no hayan sido publicados. La metodología de tipo escalonada fue utilizada para la selección de documentos a ser incluidos en el presente dictamen. De acuerdo con los criterios de elegibilidad, se priorizaron durante la selección: GPC, ETS, RS de ensayos clínicos (EC) con o sin metaanálisis (MA), y ensayos clínicos aleatorizados (ECA) de fase III. Se elaboraron estrategias de búsqueda sensibles en bases de datos bibliográficas y sitios web para obtener la evidencia científica que permita responder a la pregunta PICO. Las estrategias de búsqueda incluyeron términos relacionados con la intervención y población de interés. Se emplearon términos MeSH4, así como términos de lenguaje libre, junto con operadores booleanos para cada una de las bases de datos elegidas para la búsqueda. Los registros obtenidos de la búsqueda bibliográfica fueron importados al aplicativo web Rayyan (http://rayyan.qcri.org/) para una revisión manual por título y resumen. La selección de los estudios se realizó en una primera fase por dos evaluadores del Equipo Técnico del IETSI de manera independiente (búsqueda par); evaluando los títulos y resúmenes en relación con la pregunta PICO y seleccionando aquellos que serían evaluados a texto completo en una segunda fase por un único evaluador. En la segunda fase, uno de los evaluadores revisó los documentos a texto completo incluidos en la primera fase y realizó la selección final de los estudios. RESULTADOS: Luego de la búsqueda bibliográfica, se incluyó una GPC elaborada por la National Institute for Health and Care Excellence (NICE 2022), y un ECA de fase III, NCT01921205 (Farkas et al., 2019). CONCLUSIÓN: Por lo expuesto, el Instituto de Evaluación de Tecnologías en Salud e Investigación aprueba el uso de lacosamida para el tratamiento complementario en pacientes pediátricos con epilepsia focal refractaria, como producto farmacéutico no incluido en el Petitorio Farmacológico de EsSalud, según lo establecido en el Anexo N° 1. La vigencia del presente informe preliminar es de un año a partir de la fecha de publicación. Así, la continuación de dicha aprobación estará sujeta a la evaluación de los resultados obtenidos y de mayor evidencia que pueda surgir en el tiempo.

Formulation and characterization of lamotrigine nasal insert targeted brain for enhanced epilepsy treatment.

Lamotrigine. (LMT) is a triazine drug has an antiepileptic effect but with low water solubility, dissolution rate and thus therapeutic effect. Spanlastics are nano-vesicular carriers' act as site-specific drug delivery system. Intranasal route could direct the drug from nose to brain and provide a faster and more specific therapeutic effect. Therefore, this study aimed to upload lamotrigine onto nano-vesicles using spanlastic nasal insert delivery for effective epilepsy treatment via overcoming lamotrigine's low solubility and improving its bioavailability. Lamtrigine-loaded nano-spanlastic vesicles were prepared by ethanol injection method. To study different formulation factor's effect on formulations characters; particle size (PS), Zeta potential (ZP), polydispersity index (PDI), entrapment efficiency percentage (EE%) and LMT released amount after 6 h (Q6h); 2^1 and 3^1 full factorial designs were employed. Optimized formula was loaded in lyophilized nasal inserts formulation which were characterized for LMT release and mucoadhesion. Pharmacokinetics studies in plasma and brain were performed on rats to investigate drug targeting efficiency. The optimal nano-spanlastic formulation (F4; containing equal Span 60 amount (100 mg) and edge activator; Tween 80) exhibited nano PS (174.2 nm), high EE% (92.75%), and Q6h > 80%. The prepared nasal inserts (S4) containing 100 mg HPMC has a higher mucoadhesive force (9319.5 dyne/cm2) and dissolution rate (> 80% within 10 min) for rapid in vivo bio-distribution. In vivo studies showed considerable improvement brain and plasma's rate and extent absorption after intranasal administration indicating a high brain targeting efficiency. The results achieved indicate that nano-spanlastic nasal-inserts offer a promising LMT brain targeting in order to maximize its antiepileptic effect.

Lithium produces bi-directionally regulation of mood disturbance, acts synergistically with anti-depressive/-manic agents, and did not deteriorate the cognitive impairment in murine model of bipolar disorder.

Lithium (Li) is a well-established mood disorder treatment and may be neuroprotective. Bi-directional regulation (i.e. affecting manic symptoms and depressive symptoms) by Li has not been demonstrated. This study explored: (1) bidirectional regulation by Li in murine models of depression, mania, and bipolar disorder (BP); and (2) potential Li synergism with antidepressant/anti-mania agents. The chronic unpredictable mild stress (CUMS) and ketamine-induced mania (KM) models were used. These methods were used in series to produce a BP model. In vivo two-photon imaging was used to visualize Ca2+ activity in the dorsolateral prefrontal cortex. Depressiveness, mania, and cognitive function were assessed with the forced swim task (FST), open field activity (OFA) task, and novel object recognition task, respectively. In CUMS mice, Ca2+ activity was increased strongly by Li and weakly by lamotrigine (LTG) or valproate (VPA), and LTG co-administration reduced Li and VPA monotherapy effects; depressive immobility in the FST was attenuated by Li or LTG, and attenuated more strongly by LTG-VPA or LTG-Li; novel object exploration was increased strongly by Li and weakly by LTG-Li, and reduced by LTG, VPA, or LTG-VPA. In KM mice, Li or VPA attenuated OFA mania symptoms and normalized Ca2+ activity partially; Li improved cognitive function while VPA exacerbated the KM alteration. These patterns were replicated in the respective BP model phases. Lithium had bi-directional, albeit weak, mood regulation effects and a cognitive supporting effect. Li co-administration with antidepressant/-manic agents enhanced mood-regulatory efficacy while attenuating their cognitive-impairing effects.

Effects of treatment with clinically relevant valproate, carbamazepine, oxcarbazepine, topiramate, lamotrigine and levetiracetam on ovarian folliculogenesis in young rats.

AIM: To determine the effects of valproate (VPA), carbamazepine (CBZ), oxcarbazepine (OXC), topiramate (TPM), lamotrigine (LTG), and levetiracetam (LEV) on ovarian folliculogenesis in young rats. METHODS: Forty-nine female Wistar rats, aged 21-24 days, were divided equally into 7 experimental groups. These were given tap water over 21-24 days (control group), 300 mg/kg of VPA, 150 mg/kg of CBZ, 150 mg/kg of OXC, 100 mg/kg of TPM, 10 mg/kg of LTG, or 50 mg/kg of LEV daily in 2 doses via oral gavage until the end of puberty. At the end of the study, the estrous cycle of each rat was monitored daily, and those rats in pro-estrus or di-estrus were sacrificed and the ovaries removed. Serial sections obtained from the ovaries were stained with hematoxylin and eosin, and the corpora lutea and follicles were enumerated. Apoptotic cells were detected using the TUNEL technique. Various serial sections were immunohistochemically stained with proliferating cell nuclear antigen (PCNA), growth differentiation factor (GDF)-9, caspase-3, caspase-9, transforming growth factor beta 1 (TGF-1), and epidermal growth factor (EGF), and evaluated and photographed under a light microscope. KEY FINDINGS: The number of corpora lutea was significantly increased in the VPA, CBZ, OXC, and LTG groups compared to the control group (p < 0.001). The number of TUNEL-positive ovarian follicles was 3.3 ± 1.1 (median, 3), 6.1 ± 0.9 (median, 6), and 5.7 ± 0.8 (median,6) in the control, OXC and LEV groups, respectively (p < 0.001). The number of TUNEL-positive granulosa cells was higher in all the groups treated with antiepileptics, with the exception of the TPM group, compared to the control group (p < 0.001). HSCOREs for immunohistochemical staining using PCNA, GDF-9, TGF-1 and EGF were significantly higher in the control group than in the others (p < 0.001). HSCORE for staining using caspase-3 was significantly higher in the VPA, CBZ, OXC and LEV groups, while the HSCORE was significantly lower in the TPM group than in the control group. HSCORE for staining using caspase-9 was significantly higher in the VPA, CBZ and OXC groups, while it was significantly lower in the TPM group than in the control group (p < 0.001). SIGNIFICANCE: Exposure to VPA, CBZ, OXC, TPM, LTG and LEV caused different levels of impaired folliculogenesis in young rats.

Monitoring of lamotrigine concentrations in mothers, colostrum, and breastfed newborns during the early postpartum period.

OBJECTIVE: To analyse the concentrations of lamotrigine in maternal serum, colostrum, and serum of breastfed newborns, and to evaluate the effect of comedication with enzyme-inducing antiseizure medication and valproic acid. METHODS: This cohort study collected data from 158 women and 143 breastfed newborns. Maternal serum, milk (i.e., colostrum), and newborn serum samples were collected between the 2nd and 5th postnatal days, and lamotrigine concentrations were measured by high-performance liquid chromatography. RESULTS: The median lamotrigine concentrations were 2.7 mg/L in maternal serum, 1.4 mg/L in milk, and 1.7 mg/L in newborn serum. The median milk/maternal serum concentration ratio was 0.60, the median newborn/maternal serum concentration ratio was also 0.60, and the median newborn serum/milk concentration ratio was 1.00. A significant correlation was observed between milk and maternal serum concentrations and between newborn serum and milk concentrations, maternal serum concentrations, maternal daily dose, and dose related to maternal body weight. CONCLUSIONS: Exposure to lamotrigine in breastfed newborns is lower than exposure during pregnancy. However, by the same dose by the same mother, lamotrigine concentrations in both maternal serum and milk increase significantly after delivery. This finding, together with the immature function of eliminating enzymes in newborns, may be the reason for reaching concentrations in the reference range used for the general epileptic population in breastfed newborns. Therapeutic monitoring of breastfed newborns serum concentrations of lamotrigine is not mandatory; however, if signs of possible adverse events are noted, newborn serum concentrations should be analysed.

Cardiac sodium channel inhibition by lamotrigine: In vitro characterization and clinical implications.

Lamotrigine, approved for use as an antiseizure medication as well as the treatment of bipolar disorder, inhibits sodium channels in the brain to reduce repetitive neuronal firing and pathological release of glutamate. The shared homology of sodium channels and lack of selectivity associated with channel blocking agents can cause slowing of cardiac conduction and increased proarrhythmic potential. The Vaughan-Williams classification system differentiates sodium channel blockers using biophysical properties of binding. As such, Class Ib inhibitors, including mexiletine, do not slow cardiac conduction as measured by the electrocardiogram, at therapeutically relevant exposure. Our goal was to characterize the biophysical properties of NaV 1.5 block and to support the observed clinical safety of lamotrigine. We used HEK-293 cells stably expressing the hNaV 1.5 channel and voltage clamp electrophysiology to quantify the potency (half-maximal inhibitory concentration) against peak and late channel current, on-/off-rate binding kinetics, voltage-dependence, and tonic block of the cardiac sodium channel by lamotrigine; and compared to clinically relevant Class Ia (quinidine), Ib (mexiletine), and Ic (flecainide) inhibitors. Lamotrigine blocked peak and late NaV 1.5 current at therapeutically relevant exposure, with rapid kinetics and biophysical properties similar to the class Ib inhibitor mexiletine. However, no clinically meaningful prolongation in QRS or PR interval was observed in healthy subjects in a new analysis of a previously reported thorough QT clinical trial (SCA104648). In conclusion, the weak NaV 1.5 block and rapid kinetics do not translate into clinically relevant conduction slowing at therapeutic exposure and support the clinical safety of lamotrigine in patients suffering from epilepsy and bipolar disorder.

Common effects of bipolar disorder medications on expression quantitative trait loci genes.

The molecular mechanism(s) underpinning the clinical efficacy of the current drugs for bipolar disorder (BD) are largely unknown. This study evaluated the transcriptional perturbations potentially playing roles in the therapeutic efficacy of four commonly prescribed psychotropic drugs used to treat BD. NT2-N cells were treated with lamotrigine, lithium, quetiapine, valproate or vehicle control for 24 h. Genome-wide mRNA expression was quantified by RNA-sequencing. Incorporating drug-induced gene expression profiles with BD-associated transcriptional changes from post-mortem brains, we identified potential therapeutic-relevant genes associated with both drug treatments and BD pathophysiology and focused on expression quantitative trait loci (eQTL) genes with genome-wide association with BD. Each eQTL gene was ranked based on its potential role in the therapeutic effect across multiple drugs. The expression of highest-ranked eQTL genes were measured by RT-qPCR to confirm their transcriptional changes observed in RNA-seq. We found 775 genes for which at least 2 drugs reversed expression levels relative to the differential expression in post-mortem brains. Pathway analysis identified enriched biological processes highlighting mitochondrial and endoplasmic reticulum function. Differential expression of SRPK2 and CHDH was confirmed by RT-qPCR following multiple-dose treatments. We pinpointed potential genes involved in the beneficial effects of drugs used for BD and their main associated biological pathways. CHDH, which encodes a mitochondrial protein, had a significant dose-responsive downregulation following treatment with increasing doses of quetiapine and lamotrigine, which in combination with the enriched mitochondrial pathways suggests potential therapeutic roles and demand more studies on mitochondrial involvement in BD to identify novel treatment targets.

Exposure to anti-seizure medications impact growth of gut bacterial species and subsequent host response.

Anti-seizure medications (ASMs) are the first line of treatment for seizure control in children with epilepsy. Cumulative evidence suggests an imbalanced gut microbiota in refractory epilepsy patients. We systematically investigated the differential antimicrobial impacts of nine ASM active ingredients, seven common excipients of ASMs, and four syrup formulations on core early-life gut microbiota strains. Additionally, we evaluated the toxicity and gene expression profiles of HT-29 colon epithelial cells when exposed to active ingredients with or without bacterial supernatants. The physicochemical structure of ASM active ingredients and bacterial phylogeny were found to be related to ASM toxicity. Carbamazepine, lamotrigine, and topiramate reduced the growth of more than ten strains along with syrup excipient propyl-paraben. Various artificial sweeteners present in ASM formulations stimulated the growth of gut bacterial strains. The active ingredients that were more toxic to bacterial strains also exhibited toxicity towards HT-29 cells, yet Bifidobacterium longum supernatant reduced cytotoxic effects of carbamazepine and lamotrigine. Akkermansia muciniphila or mixed community supernatants reduced the expression of drug resistance genes in HT-29 cell lines. In summary, our results indicate that several ASM active ingredients and their excipients regulate the growth of gut bacterial strains in a species-specific manner. Interactions between ASMs and gut epithelial cells might be modulated by gut microbial metabolites.

Spontaneous and TMS-related EEG changes as new biomarkers to measure anti-epileptic drug effects.

Robust biomarkers for anti-epileptic drugs (AEDs) activity in the human brain are essential to increase the probability of successful drug development. The frequency analysis of electroencephalographic (EEG) activity, either spontaneous or evoked by transcranial magnetic stimulation (TMS-EEG) can provide cortical readouts for AEDs. However, a systematic evaluation of the effect of AEDs on spontaneous oscillations and TMS-related spectral perturbation (TRSP) has not yet been provided. We studied the effects of Lamotrigine, Levetiracetam, and of a novel potassium channel opener (XEN1101) in two groups of healthy volunteers. Levetiracetam suppressed TRSP theta, alpha and beta power, whereas Lamotrigine decreased delta and theta but increased the alpha power. Finally, XEN1101 decreased TRSP delta, theta, alpha and beta power. Resting-state EEG showed a decrease of theta band power after Lamotrigine intake. Levetiracetam increased theta, beta and gamma power, while XEN1101 produced an increase of delta, theta, beta and gamma power. Spontaneous and TMS-related cortical oscillations represent a powerful tool to characterize the effect of AEDs on in vivo brain activity. Spectral fingerprints of specific AEDs should be further investigated to provide robust and objective biomarkers of biological effect in human clinical trials.

Evaluation of serum levels of asprosin and other metabolic profiles in patients with idiopathic tonic-clonic generalized epilepsy on treatment with valproic acid.

BACKGROUND: This cross-sectional research was undertaken to determine the serum levels of asprosin, a novel white adipose tissue-derived glucogenic adipokine, in epileptic patients on valproic acid treatment. METHODS: Sixty-six patients diagnosed with idiopathic tonic-clonic generalized epilepsy were divided into three groups: those treated with valproic acid (n = 22), those treated with lamotrigine (n = 22), and twenty-two newly diagnosed or untreated patients. A control group was twenty-two, healthy volunteers with a similar distribution of gender and age. Body mass index (BMI) and fasting serum levels of asprosin, glucose, glycohemoglobin (HbA1c), insulin, and lipid profile were measured for both patients and control groups. Additionally, homeostasis model assessment for insulin resistance (HOMA-IR) was also calculated for the investigated groups. RESULTS: The mean BMI values and fasting serum levels of glucose, HbA1c, insulin, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and triglyceride were much higher in subjects treated with valproic acid than those in the other study groups. Furthermore, a higher number of participants in the valproic acid group fulfilled the insulin resistance criterion (defined as HOMA-IR > 2.5) compared with those in other study groups. The mean fasting serum asprosin concentration was also significantly higher in the valproic acid group than in other study groups. This was while the values of the study parameters were comparable in the healthy, un-treated, and lamotrigine groups. CONCLUSIONS: Our finding suggested that elevated asprosin level might be one of the pathological mechanisms involved in the development of obesity, insulin resistance, and metabolic disturbances related to valproic acid treatment.

Effects of antiepileptic drugs on ovaries of female Wistar rats.

Valproate (VPA) induced changes in ovarian morphology are observed in humans with epilepsy and in non-epileptic animals. The effects of lamotrigine (LTG) on female reproduction is not well known. We investigated whether LTG might be a safer drug for use with patients of reproductive age. Forty Wistar albino female rats were divided into five groups. The control group was injected with saline-vehicle solution. The low dose (LD)-VPA group was injected with 100 mg/kg VPA. The high dose (HD)-VPA group was injected with 500 mg/kg VPA. The LD-LTG group was injected with 10 mg/kg LTG. The HD-LTG group was injected with 50 mg/kg LTG. We evaluated histological and biochemical changes in the ovaries. The number of atretic and cystic follicles was increased in the HD-VPA and HD-LTG groups compared to the control group. A significant increase in malondialdehyde level was found in the VPA groups compared to the control and LTG groups. No significant differences in total glutathione levels or superoxide dismutase activity were found among study groups. Catalase activity was significantly higher in HD-VPA and HD-LTG groups compared to the control, LD-VPA and LD-LTG groups. Prevalence and intensity of caspase-3 immunoreactivity in the luteal cells were significantly greater in the HD-LTG group compared to the control group. VPA administration caused polycystic ovarian syndrome-like changes in the ovary. We found that LD-LTG, which reflects the dose for humans, might be a safer option for use during the reproductive age.

Effects of Lamotrigine and Topiramate on Glial Properties in an Astrocyte-Microglia Co-Culture Model of Inflammation.

BACKGROUND: Astrocytes and microglia are involved in the pathophysiology of epilepsy and bipolar disorder with a link to inflammation. We aimed to investigate the effects of the antiepileptic and mood-stabilizing drugs lamotrigine (LTG) and topiramate (TPM) on glial viability, microglial activation, cytokine release, and expression of gap-junctional protein connexin 43 (Cx43) in different set-ups of an in vitro astrocyte-microglia co-culture model of inflammation. METHODS: Primary rat co-cultures of astrocytes containing 5% (M5, representing "physiological" conditions) or 30% (M30, representing "pathological, inflammatory" conditions) of microglia were treated with different concentrations of LTG and TPM for 24 hours. An 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to measure the glial cell viability. The microglial activation state was analyzed by immunocytochemistry. The pro-inflammatory tumor necrosis factor-α (TNF-α) and anti-inflammatory transforming growth factor-ß1 (TGF-ß1) cytokine levels were measured by enzyme-linked immunosorbent assay. The astroglial Cx43 expression was quantified by western blot. RESULTS: A significant reduction of the glial cell viability after incubation with LTG or TPM was observed in a concentration-dependent manner under all conditions. LTG caused no significant alterations of the microglial phenotypes. Under pathological conditions, TPM led to a significant concentration-dependent reduction of microglial activation. This correlated with increased astroglial Cx43 expression. TNF-α levels were not affected by LTG and TPM. Treatment with higher concentrations of LTG, but not with TPM, led to a significant increase in TGF-ß1 levels in M5 and M30 co-cultures. CONCLUSIONS: Despite the possible glial toxicity of LTG and TPM, both drugs reduced inflammatory activity, suggesting potential positive effects on the neuroinflammatory components of the pathogenesis of epilepsy and bipolar disorder.