The use of valproic acid (VPA) (also known as Depakote, Depakene, and others) frequently results in elevated plasma ammonia. In some people, hyperammonemia may be clinically significant, resulting in hyperammonemic encephalopathy, which may be severe. Valproic acid-induced hyperammonemic encephalopathy may occur in people with normal liver function, despite normal doses and serum levels of VPA. We describe 2 cases of valproic acid-induced hyperammonemic encephalopathy in patients with supratherapeutic VPA levels, although the condition has been described in people with normal VPA levels. With the increasing indications and off-label uses of VPA, family physicians should be aware of this potential complication of VPA and check ammonia levels in patients taking VPA who present with alterations in mental status. Treatment with L-carnitine may be beneficial in reducing ammonia levels. Valproic acid (VPA) is effective in the treatment of seizure disorders, bipolar disorder, migraine headache prophylaxis, neuropathic pain, restless legs syndrome, dementia-related agitation, and social anxiety disorder, among other conditions. VPA has numerous drug interactions and toxicities; severe toxicities include hepatic damage, pancreatitis, teratogenicity, thrombocytopenia, and hyperammonemia. Here we depict 2 case reports of VPA-induced hyperammonemic encephalopathy (VHE), both occurring in patietns with no history of underlying liver disease. In one instance, the patient was able to function, but with significant cognitive limitations. In the second case, the patient was comatose. Both of the patients we describe also had supratherapeutic VPA levels, but VHE is a well-documented potential complication of the use of VPA in the medical literature, and it may occur in people with normal VPA levels.1 Because of the wide spectrum of symptoms associated with VHE, physicians should consider hyperammonemia in the differential diagnosis of any patient taking VPA who shows changes in behavior, cognition, or orientation

Cette étude a été réalisée dans le but d’obtenir une meilleure connaissance du métabolisme cérébral qui se trouve perturbé dans de nombreuses maladies neurologiques ou bien par des médicaments présentant des effets toxiques au niveau du système nerveux central. Pour cela, nous avons utilisé notre approche de métabolomique cellulaire qui combine les techniques de dosages enzymatiques et de spectroscopie RMN du carbone 13 avec des modèles mathématiques des voies métaboliques. Dans la première partie de ce travail, nous avons caractérisé le métabolisme des tranches de cerveau de rat en utilisant les principaux substrats du cerveau. Nos tranches utilisent ces différents substrats et conservent une haute capacité d’oxydation pendant la durée d’incubation. La deuxième partie présente une validation de notre modèle d’étude en testant l’effet du valproate, un médicament antiépileptique très utilisé. Nous montrons, non seulement une augmentation de l’accumulation du GABA et une diminution de celle de l’aspartate dues au valproate, mais aussi une perturbation des flux à travers différentes enzymes du métabolisme du cerveau. Dans la troisième partie, nous avons recherché les effets des composés guanidiniques sur le métabolisme cérébral ; ces composés augmentent l’utilisation de glucose et l’accumulation de lactate par les tranches de cerveau de rat. Nos tranches représentent donc un bon modèle pour les études métaboliques in vitro et notre approche permet d’obtenir une vision d'ensemble du devenir métabolique d'un substrat donné et d'identifier les voies métaboliques impliquées en mesurant les flux enzymatiques en absence et en présence d'un agent pharmacologique ou toxicologique / This study was conducted to obtain a better knowledge of brain metabolism which is altered in many neurological diseases or by drugs with toxic effects on the central nervous system. For this purpose, we used our cellular metabolomic approach that combines enzymatic and carbon 13 NMR measurements with mathematical modeling of metabolic pathways. In the first part of this work, we characterized the metabolism of rat brain slices by using the main substrates of the brain. Our slices metabolized and oxidized these substrates at high rates during the incubation period. The second part presents a validation of our model of study by testing the effect of valproate, a widely used antiepileptic drug. We showed that valproate not only increases the accumulation of GABA and decreases that of aspartate, but also alters fluxes through several enzymes involved in brain metabolism. In the third part, we investigated the effects of guanidino compounds on cerebral metabolism; these compounds increase glucose consumption and lactate accumulation by rat brain slices. Thus, our slices are a good model for metabolic studies in vitro and our approach provides an overview of the metabolic fate of a given substrate and allows to identify the metabolic pathways involved by measuring enzymatic fluxes in the absence and the presence of a pharmacological or toxicological agents

La carbamazépine est une molécule antiépileptique très largement utilisée au point de devenir un marqueur environnemental de l'activité humaine. Elle donne lieu à des réactions d'hypersensibilité particulières, rares mais potentiellement létales, associant manifestations cutanées, hyperéosinophilie et atteintes multi-organiques (DRESS syndrome). Les hypothèses physiopathologiques font principalement appel aux métabolites de la carbamazépine mais la voie métabolique minoritaire des dérivés acridiniques est peu explorée. Les résultats obtenus à partir de stimulations ex vivo en laboratoire indiquent d'une part que l'acridine stimule la sécrétion d'interleukine-5 (facteur de croissance principal des éosinophiles), et d'autre part que la formation d'acridine et d'acridone est possible dans le sang à partir de métabolites primaires (époxyde et iminostilbène). Les données cliniques montrent une diminution des taux sanguins du 9-hydroxyméthyl-10-carbamoylacridan et du rapport acridine/acridone au cours de l'état de DRESS. Le co-traitement par l'acide valproïque majore le taux basal d'IL-5 et oriente en partie le profil métabolique vers celui du DRESS. L'étude de l'action des procédés oxydatifs environnementaux indique que les lits bactériens et le lagunage augmentent le rejet d'acridine. Nos travaux en pharmacologie humaine positionnent l'acridine et l'acridone comme des métabolites sanguins, a minima marqueurs et a maxima acteurs de la physiopathologie du DRESS. L'établissement d'un profil métabolique apparaît justifié lors d'une co-thérapie avec l'acide valproïque chez des patients à terrain atopique. L'acridine semble également être un marqueur environnemental d'intérêt. / Carbamazepine is a very usefull antiepileptic drug, widely used at the point of becoming an environmental marker of human activity. It is giving rise to rare but potentially lethal hypersensitivity reactions, with specific combination of skin manifestations, eosinophilia and multi-organ damage (DRESS syndrome). The pathophysiological hypotheses rely primarily to metabolites of carbamazepine, but the minor pathway of acridinic derivatives is little explored.The results obtained from ex vivo stimulation in our laboratory suggest both that acridine stimulates the secretion of interleukin-5 (main growth factor of eosinophils), and that the formation of acridine and acridone is possible in blood from primary metabolites (epoxide and iminostilbene). Clinical data show a decrease in blood levels of 9-hydroxymethyl-10-carbamoylacridan and in the ratio (acridine / acridone) during the state of DRESS. Co-treatment with valproic acid increases the basal rate of IL-5 and diverts, at least in part, to the metabolic profile of DRESS. The study of the action of environmental oxidative processes indicates that the purification processes by trickling filters and stabilization ponds increase the release of acridine, while activated sludge systems have little impact.Our work in human pharmacology positions acridine and acridone as regular blood metabolites, involved as markers or actors of the pathophysiology of DRESS. The determination of the metabolic profile appears warranted for atopic patients requiring co-therapy with valproic acid. Acridine also appears to be a marker of environmental interest.

Ellipticine is a potent antineoplastic agent, whose mode of action is considered to be based mainly on DNA intercalation and inhibition of topoisomerase II. Ellipticine was also found to form covalent DNA adducts mediated by its enzymatic activation with cytochromes P450 (CYP) and peroxidases. The next study demonstrated increasing formation of these ellipticine-DNA adducts by histone deacetylase inhibitor valproate (VPA) in neuroblastoma cells. This phenomenon correlates with increasing cytotoxicity of ellipticine induced by this histone deacetylase inhibitor. This observation can be explained by several mechanisms. One of them can be loosening the structure of chromatine, which leads to accessing DNA for modification. Another one is the effect of VPA on activities and expression of enzymes metabolizing ellipticine. This study was aimed to test the second hypothesis. Since VPA has been shown to be metabolized by similar enzymes as ellipticine is, we have studied the effect of VPA (i) on oxidation of ellipticine by cytochromes P450 and peroxidases, (ii) on activities of the CYP enzymes, which significantly participate in oxidation of ellipticine (CYP1A, CYP3A) and (iii) on expression of enzymes oxidizing ellipticine (CYP1A1, CYP3A4, lactoperoxidase). Oxidation of ellipticine in vitro by model...

L’HTLV-1 est l’agent étiologique de la TSP/HAM et de l’ATL. La TSP/HAM est une méningomyélite chronique d’évolution lente et progressive. La charge provirale HTLV-1 est corrélée à l’évolutivité de la maladie. La protéine virale Tax module la synthèse et la fonction de multiples protéines de la prolifération et de la survie des lymphocytes T infectés. L’expression virale n’est pas toujours détectable in vivo. Une modulation épigénétique par inhibiteurs d’HDAC a été proposée. Des travaux dans le modèle du BLV et in vitro dans l’infection à HTLV-1 ont conforté ce concept et conduit à un essai thérapeutique évaluant le VPA dans le traitement de la TSP/HAM, qui n’a pas montré d’impact sur la charge provirale. Nous nous sommes intéressés à l’effet du VPA sur les lymphocytes T CD4+ en culture, cibles du virus HTLV-1. L’expression du génome viral, surtout la balance entre les protéines Tax et HBZ a été étudiée avec ou sans VPA. Son expression serait corrélée à la charge provirale et à l’évolution de la TSP/HAM. Nous montrons qu’un tiers des cellules CD4+ infectées expriment Tax. Cette proportion augmente sous VPA. La détection de la protéine p19 est augmentée sous VPA. La stimulation par le VPA de la transcription sens du génome viral a été confirmée par quantification des messagers Tax et Gag alors que l’expression d’HBZ se trouve réprimée sous VPA. Les données cinétiques d’expression spontanée d’HBZ montrent l’existence d’un rétrocontrôle négatif exercé par HBZ sur l’expression de Tax et des gènes structuraux. Influer sur l’expression d’HBZ ouvre une voie nouvelle pour le traitement des maladies associées à HTLV-1. / HTLV-1 is the etiological agent of HAM/TSP and ATL. TSP/HAM is a chronic meningomyelitis with a course being slow and progressive. HTLV-1 proviral load correlates with disease progression. Tax protein modulates the synthesis and function of proteins involved in the regulation of infected T-lymphocytes proliferation and survival. Viral expression is not always detectable in vivo. An epigenetic modulation by the use of HDAC inhibitors has been proposed. A study in the BLV model and an in vitro study in a HTLV-1 infection have lead to a therapeutic assay in order to assess VPA in the treatment of HAM/TSP. This assay did not show any impact on the proviral load. We evaluated the impact of VPA treatment on viral genome expression in cultured lymphocytes, especially the balance between Tax and HBZ. A third of provirus-positive CD4+ T cells spontaneously became Tax-positive. The estimation rose up to two-thirds of Tax-positive infected cells when VPA was added. VPA enhanced Gag p19 protein release. VPA treatment enhanced and prolonged Tax mRNA expression, while it blocked HBZ expression. Our data are consistent with the hypothesis of a feed-back loop coordinating Tax and HBZ expression. Modulation of HBZ expression may impact the net outcome of VPA treatment on HTLV-1-infected cell proliferation and survival.

Schizophrenia postmortem brain is characterized by γ aminobutyric acid downregulation and by decreased dendritic spine density in frontal cortex. Protracted L-methionine treatment exacerbates schizophrenia symptoms, and our earlier work (Tremolizzo et al. and Dong et al.) has shown that L-methionine decreases reelin and GAD67 transcription in mice which is prevented by co-administration of valproate. In this study, we observed a decrease in spine density following L-methionine treatment, which was prevented by co-administration of valproate. Together with our earlier findings conducted under the same experimental conditions, we suggest that downregulation of spine density in L-methionine-treated mice may be because of the decreased expression of reelin and that valproate may prevent spine downregulation by inhibiting the methylation induced decrease in reelin.

Thesis ((M. Pharm. (Pharmaceutics)) -- University of Limpopo, 2019 / Epilepsy is the fourth most common neurological disorder after migraine, stroke and Alzheimer’s disease and it affects about fifty million people worldwide. Careful consideration should be taken when deciding to initiate treatment in epilepsy as it should consider the balance between the possibility of further seizures and their associated risks, including the possible risk of sudden expected death, inconvenience and the risks of taking regular medication for each individual. In the early 1980’s, the first-line treatment for epilepsy was polytherapy. This was due to findings that smaller doses of two drugs rather than larger doses of one drug can achieve synergistic effects or less drug toxicity. However, following more trials on the treatment of epilepsy, this was later changed to monotherapy as first-line treatment. Despite the change, patients remain uncontrolled on a single anti-epileptic drug, thus they are initiated on polytherapy, one such combination being carbamazepine in combination with sodium valproate. The use of these in combination has pharmacological threats such as compliance, the control of side effects and the achievement of synergistic effects. The development of a Fixed Dose Combination (FDC) has often been used to resolve pharmacological threats, and this study aims to develop a fixed dose combination tablet of carbamazepine and sodium valproate to resolve the pharmacological threats in epilepsy. Samples of carbamazepine and sodium valproate and a physical mixture (1:1 w/w) of both drugs and excipients were prepared for compatibility with thermal analysis and spectroscopy techniques. Data was analysed by comparing the DSC curves, FTIR spectra, XRPD peaks and TAM analysis of carbamazepine and sodium valproate alone and in their physical mixture (1:1 w/w) and with excipients. Both carbamazepine and sodium valproate were evaluated for flowability using angle of repose, tapped and bulk density, compressibility index and particle size distribution. To formulate the proposed FDC tablet of carbamazepine and sodium valproate, direct compression and wet granulation methods were employed. The tablets were then evaluated for official and non-official post formulation parameters (weight variation, crushing strength, friability, diameter and thickness, and disintegration) according to BP and USP standards. A standardised HPLC method was developed and validated for analytical procedures. Dissolution studies were conducted xiii according to USP methods to verify and quantify the release of the APIs from the FDC tablet. Carbamazepine and sodium valproate were tested for compatibility with excipients using DSC, FTIR, XRPD and TAM analysis. The overall results confirmed that carbamazepine and sodium valproate are compatible, with each other and the excipients used in the study. Powder flow of carbamazepine and sodium valproate was poor, hence they were subjected to granulation prior to compression to improve flowability. The specifications of the fixed-dose combination were developed in accordance with the FDA’s quality by design concept and WHO recommendations. The tablets were subjected to non-official and official pharmacopoeial tests, and passed all the tests. Dissolution studies according to a USP method were conducted to verify and quantify the release of the APIs in the fixed-dose combination. The initial dissolution rate (DRi) of carbamazepine and sodium valproate in the SLS dissolution medium was rapid as required for an immediate release formulation. The study aimed at developing a fixed dose combination of carbamazepine and sodium valproate to try to reduce the burden of taking more than one tablet for epilepsy. Based on the results obtained from preformulation studies to assay of the final product, the study was successful. / Chieta bursary and HWseta

A associação de ácido valpróico/ divalproato de sódio e lamotrigina tem se mostrado eficaz no tratamento das epilepsias refratárias, tendo como limitador ao seu uso os efeitos adversos, principalmente numa população de crianças e adolescentes, onde esses efeitos são maximizados. Este estudo clínico tem como objetivo avaliar as propriedades farmacológicas da associação valproato/divalproato de sódio e lamotrigina em uma população pediátrica refratária ao tratamento medicamentoso usando método de introdução e escalonamento mais lento do que o preconizado, com seguimento prolongado. Para tal, foi estudado um grupo de 51 crianças e adolescentes com epilepsia de difícil controle, com idades de 4 a 16 anos (mediana de 8 anos), sendo 27 (52,9%) meninas. Dezesseis (31,4%) crianças apresentavam epilepsia generalizada; 35 (68,6%), epilepsia parcial. A associação valproato/divalproato de sódio e lamotrigina foi eficaz no primeiro ano de acompanhamento para 39 (76,5 %) pacientes. No segundo ano de tratamento, esta associação foi eficaz para 36 (70,6%) pacientes. Houve melhora dos drop attacks em 22 pacientes (88,5%), mas não houve especificidade em relação à síndrome ou crise epiléptica. Efeitos adversos observados foram rash, em quatro (7,8%) pacientes, com descontinuidade do tratamento, e tremores sutis em seis (11,7%), resolvidos com a diminuição da dose da lamotrigina. A descontinuidade ocorreu em 12 (23,5%) pacientes, sendo que a maior razão foi o rash cutâneo, seguido pela perda da eficácia ao tratamento, em oito (15,7%) pacientes. Concluímos que, com a proposta de introdução mais lenta da lamotrigina, os efeitos adversos são minimizados (principalmente os referentes ao sistema nervoso central), assim como há melhora das crises debilitantes, que comprometem a qualidade de vida desses pacientes, tendo como resultado uma maior adesão ao esquema terapêutico. Além disso, pontuamos que a eficácia terapêutica se mantém com doses mais baixas de lamotrigina, mesmo após o primeiro ano de tratamento / The association lamotrigine and sodium valproate/divalproex sodium has been shown to be effective in the treatment of refractory epilepsy, having as a limiting factor for its use, adverse effects, especially in a population of children and adolescents where these effects are maximized. This clinical study aims to evaluate the pharmacological properties of this association in a pediatric population refractory to medical treatment using a method of introduction and titration slower than the usually recommended, with extended follow-up. For this purpose, we studied a group of 51 children and adolescents, with refractory epilepsy, ranging from 4 to 16 years old (median 8 years), with 27 (52.9%) girls. Sixteen (31.4%) children presented generalized and 35 (69.6%) focal epilepsy. The association sodium valproate/ divalproex sodium and lamotrigine was effective in the first year of followup in 39 (76.5%) patients. In the second year of treatment this combination was effective in 36 (70.6%) patients. An improvement of drop attacks was observed in 22 (88.5%) patients, but there was no specificity as to the epileptic syndrome or seizure type. Adverse effects were rash, leading to discontinuation in four (7.8%), and subtle tremors, that resolved with reduction of the dose of lamotrigine in six (11.7%) patients. In twelve (23.5%) patients treatment was withdrawn, because of rash (7.8%) and loss of efficacy, in eight (15.7%) patients. We concluded that with the proposed slower introduction of lamotrigine, adverse effects are minimized, especially in the central nervous system, as well as better obtained control of debilitating seizures, affecting quality of life, and resulting in better adherence to the therapeutic scheme. Furthermore, we point out that the therapeutic efficacy is maintained with lower doses of lamotrigine, even after the first year of treatment

A associação de ácido valpróico/ divalproato de sódio e lamotrigina tem se mostrado eficaz no tratamento das epilepsias refratárias, tendo como limitador ao seu uso os efeitos adversos, principalmente numa população de crianças e adolescentes, onde esses efeitos são maximizados. Este estudo clínico tem como objetivo avaliar as propriedades farmacológicas da associação valproato/divalproato de sódio e lamotrigina em uma população pediátrica refratária ao tratamento medicamentoso usando método de introdução e escalonamento mais lento do que o preconizado, com seguimento prolongado. Para tal, foi estudado um grupo de 51 crianças e adolescentes com epilepsia de difícil controle, com idades de 4 a 16 anos (mediana de 8 anos), sendo 27 (52,9%) meninas. Dezesseis (31,4%) crianças apresentavam epilepsia generalizada; 35 (68,6%), epilepsia parcial. A associação valproato/divalproato de sódio e lamotrigina foi eficaz no primeiro ano de acompanhamento para 39 (76,5 %) pacientes. No segundo ano de tratamento, esta associação foi eficaz para 36 (70,6%) pacientes. Houve melhora dos drop attacks em 22 pacientes (88,5%), mas não houve especificidade em relação à síndrome ou crise epiléptica. Efeitos adversos observados foram rash, em quatro (7,8%) pacientes, com descontinuidade do tratamento, e tremores sutis em seis (11,7%), resolvidos com a diminuição da dose da lamotrigina. A descontinuidade ocorreu em 12 (23,5%) pacientes, sendo que a maior razão foi o rash cutâneo, seguido pela perda da eficácia ao tratamento, em oito (15,7%) pacientes. Concluímos que, com a proposta de introdução mais lenta da lamotrigina, os efeitos adversos são minimizados (principalmente os referentes ao sistema nervoso central), assim como há melhora das crises debilitantes, que comprometem a qualidade de vida desses pacientes, tendo como resultado uma maior adesão ao esquema terapêutico. Além disso, pontuamos que a eficácia terapêutica se mantém com doses mais baixas de lamotrigina, mesmo após o primeiro ano de tratamento / The association lamotrigine and sodium valproate/divalproex sodium has been shown to be effective in the treatment of refractory epilepsy, having as a limiting factor for its use, adverse effects, especially in a population of children and adolescents where these effects are maximized. This clinical study aims to evaluate the pharmacological properties of this association in a pediatric population refractory to medical treatment using a method of introduction and titration slower than the usually recommended, with extended follow-up. For this purpose, we studied a group of 51 children and adolescents, with refractory epilepsy, ranging from 4 to 16 years old (median 8 years), with 27 (52.9%) girls. Sixteen (31.4%) children presented generalized and 35 (69.6%) focal epilepsy. The association sodium valproate/ divalproex sodium and lamotrigine was effective in the first year of followup in 39 (76.5%) patients. In the second year of treatment this combination was effective in 36 (70.6%) patients. An improvement of drop attacks was observed in 22 (88.5%) patients, but there was no specificity as to the epileptic syndrome or seizure type. Adverse effects were rash, leading to discontinuation in four (7.8%), and subtle tremors, that resolved with reduction of the dose of lamotrigine in six (11.7%) patients. In twelve (23.5%) patients treatment was withdrawn, because of rash (7.8%) and loss of efficacy, in eight (15.7%) patients. We concluded that with the proposed slower introduction of lamotrigine, adverse effects are minimized, especially in the central nervous system, as well as better obtained control of debilitating seizures, affecting quality of life, and resulting in better adherence to the therapeutic scheme. Furthermore, we point out that the therapeutic efficacy is maintained with lower doses of lamotrigine, even after the first year of treatment

Cancer cells are able to adapt to different stress factors such as hypoxia, which is caused by insufficient tumor vascularization. An increased acetylation status of histones H3 and H4 in UKF-NB-3 and UKF-NB-4 neuroblastoma cell lines was found to be a mechanism of adaptation of these cells to hypoxia. An increase in acetylation of histones H3 and H4 is suggested to cause changes in the structure of chromatin that lead to activation of gene transcription. In addition, cultivation of tested neuroblastoma cells under hypoxic conditions changes expression of proteins of a transcription factor N-myc, which is essential for development of neuroblastomas. This transcription factor is also responsible for a metabolic adaptation of neuroblastoma cells, increases their aggressiveness and its expression leads to a worse prognosis of the disease. Inhibitors of histone deacetylases (HDAC) are suggested to be the promising agents exhibiting various anticancer effects. They can induce cell cycle arrest, differentiation or programmed cell death in sensitive tumors. In this study, the effect of one of inhibitors of HDACs, valproate, on expression of proteins of transcription factors N-myc and hypoxia inducible factor 1α (HIF-1α) was investigated. Valproate decreases protein levels of both transcription factors in...