Valproic acid toxicity: overview and management

Alteration in folate carrier expression via histone deacetylase inhibition in BeWo human placental choriocarcinoma cells

Folates are essential nutrients for fetal development during pregnancy. Valproic acid (VPA), an inhibitor of histone deacetylases (HDACs), alters the expression of folate carriers in placental cells; however, the underlying mechanisms remain unclear. Here, we aimed to determine the profiles of folate carriers (folate receptor alpha [FOLR1], solute carrier [SLC]-19A1, and SLC46A1) after inhibition of HDACs, especially class I and IIa HDACs, using different inhibitors and gene knockdown tests. Quantitative polymerase chain reaction revealed that BeWo cells (a trophoblast model) expressed HDACs and folate carriers, similar to human placental villi. FOLR1 expression was upregulated by VPA, apicidin, and trichostatin A, but downregulated by MS-275 after 24 h treatment. VPA and apicidin upregulated the expression of SLC46A1. These inhibitors downregulated SLC19A1 expression. TMP269 (a class IIa inhibitor) did not affect folate carrier levels. HDAC1/2 knockdown upregulated FOLR1 and SLC46A1 levels, whereas HDAC1/3 knockdown downregulated FOLR1 levels. Our findings suggest that the pharmacological inhibition of class I HDACs alters the expression of folate carriers in BeWo cells. By contrast, HDAC inhibitors exert different regulatory effects on folate carriers. Moreover, HDAC1/2 inhibition may be a potential mechanism involved in altering FOLR1 and SLC46A1 levels.

Transient Arginine Vasopressin Deficiency Induced by Valproic Acid Intoxication: A Case Report

Valproic acid is commonly used for treating seizures and psychiatric disorders. Valproic acid is a common anticonvulsant drug causing overdose for suicidal purposes. The most common symptom of valproic acid poisoning is central nervous system damage. Most cases result in mild to moderate drowsiness, while in severe cases, fatal cerebral edema and coma have been reported. Other complications include respiratory depression, hepatotoxicity, thrombocytopenia, and multi-organ failure resulting in circulatory collapse. Herein, we present a case of a 42-year-old woman who ingested an overdose of 600 mg nitrazepam, 50 mg olanzapine, and 35,600 mg valproic acid. The maximum daily doses for nitrazepam, olanzapine, and valproic acid are 15, 20, and 1200 mg, respectively. This overdose led to reversible arginine vasopressin (AVP) deficiency as a rare but significant complication. The deficiency led to polyuria with dilute urine, which was effectively suppressed by AVP administration. This case highlights the potential for reversible AVP deficiency as a rare but significant complication of valproic acid overdose. Early diagnosis and appropriate management are crucial for favorable outcomes.

Simultaneous, Dual Continuous Venovenous Haemodiafiltration as Salvage Therapy for Severe Sodium Valproate Intoxication

Sodium valproate overdose leads to CNS depression, cerebral oedema, and severe metabolic acidosis in cases of severe toxicity. Extracorporeal removal, specifically through intermittent haemodialysis, is recommended, though not always tolerated by or accessible to haemodynamically unstable patients in intensive care units. We present a case of a male in his mid-twenties presenting following a massive, intentional overdose of 13 g of sodium valproate over 7 hours, with an initial valproate blood concentration of 975 μg/ml (normal 50-100 μg/ml). He was hypoxic and severely acidotic on arrival and was given fluids and L-carnitine according to TOXBASE guidelines. This resulted in only marginal improvement to his acidosis. Once transferred to our intensive care unit, the patient was started on inotropic support followed by continuous venovenous hemofiltration (CVVHDF) at the maximum effluent rate of 60 ml/kg/hr. Due to his persisting metabolic acidosis and worsening hyperlacataemia, dual CVVHDF was started by adding another filter in series after 26 hours, increasing the maximum effluent rate to 96 ml/kg/hr. The patient remained on dual CVVHDF for 31 hours, during which his acidosis and lactate showed considerable improvement, and he was subsequently stepped down to single-filter CVVHDF for a further 20 hours until complete resolution of his acidosis. This case report recognises dual CVVHDF as a viable salvage therapy for severe sodium valproate overdose by facilitating the achievement of a higher effluent flow rate compared to what can be accomplished with single-filter CVVHDF.

Innovative non-targeted screening approach using High-resolution mass spectrometry for the screening of organic chemicals and identification of specific tracers of soil and dust exposure in children

Environmental contamination through direct contact, ingestion and inhalation are common routes of children's exposure to chemicals, in which through indoor and outdoor activities associated with common hand-to-mouth, touching objects, and behavioral tendencies, children can be susceptible and vulnerable to organic contaminants in the environment. The objectives of this study were the screening and identification of a wide range of organic contaminants in indoor dust, soil, food, drinking water, and urine matrices (N = 439), prioritizing chemicals to assess children's environmental exposure, and selection of unique tracers of soil and dust ingestion in young children by non-targeted analysis (NTA) using Q-Exactive Orbitrap followed data processing by the Compound Discoverer (v3.3, SP2). Chemical features were first prioritized based on their predominant abundance (peak area>500,000), detection frequency (in >50% of the samples), available information on their uses and potential toxicological effects. Specific tracers of soil and dust exposure in children were selected in this study including Tripropyl citrate and 4-Dodecylbenzenesulfonic acid. The criteria for selection of the tracers were based on their higher abundance, detection frequency, unique functional uses, measurable amounts in urine (suitable biomarker), and with information on gastrointestinal absorption, metabolism, and excretion, and were further confirmed by authentic standards. We are proposing for the first time suitable unique tracers for dust ingestion by children.

Transcriptomic profile of human iPSC-derived podocyte-like cells exposed to a panel of xenobiotics

Podocytes play a critical role in the formation and maintenance of the glomerular filtration barrier and injury to these cells can lead to a breakdown of the glomerular barrier causing permanent damage leading to progressive chronic kidney disease. Matured podocytes have little proliferative potential, which makes them critical cells from a health perspective, but also challenging cells to maintain in vitro. Differentiating podocyte-like cells from induced pluripotent stem cells (iPSC) provides a novel and continuous source of cells. Here, we investigated the effect of a 24-h exposure to eight compounds, including the known glomerular toxins doxorubicin and pamidronate, on transcriptomic alterations in iPSC derived podocytes. Doxorubicin (50 nM), pamidronate (50 μM), sodium arsenite (10 μM), and cyclosporine A (15 μM) had a strong impact on the transcriptome, gentamicin (450 μg/ml), lead chloride (15 μM) and valproic acid (500 μM) had a mild impact and busulfan (50 μM) exhibited no impact. Gene alterations and pathways analysis provided mechanistic insight for example, doxorubicin exposure affected the p53 pathway and dedifferentiation, pamidronate activated several pathways including HIF1alpha and sodium arsenite up-regulated oxidative stress and metal responses. The results demonstrate the applicability of iPSC derived podocytes for toxicological and mechanistic investigations.

Effects of valproic acid and levetiracetam monotherapy on balance functions in patients with generalized epilepsy

BACKGROUND

It is reported that antiepileptic drugs have an effect on balance functions. The aim of the study was to evaluate and compare the effects of valproic acid and levetiracetam monotherapy on balance functions in patients with generalized epilepsy using objective test methods.

METHODS

The study included 43 generalized epilepsy patients aged 18-60 years, including 20 patients receiving valproic acid monotherapy, 23 patients receiving levetiracetam monotherapy, and 25 healthy individuals as controls, in the Neurology Clinic of a university hospital in eastern Turkey. The demographic data form was filled out and the Video Head Impulse Test and Vestibular Evoked Myogenic Potentials test were performed.

RESULTS

Statistically significant differences were obtained between the groups in lateral, posterior, and anterior semicircular canal gains and RALP and LARP asymmetry values in the V-HIT test (p < 0.05). Statistically significant differences were obtained between the groups in P1, N1 latency and asymmetry values in the C-VEMP test and in N1, P1 latency, amplitude, and asymmetry values in the o-VEMP test (p < 0.05).

CONCLUSION

Valproic acid and levetiracetam may affect the vestibulocular and vestibulocolic reflex pathways negatively. In this cohort, valproic acid had more pronounced adverse effects on balance functions as compared to levetiracetam.

Zinc-Dependent Histone Deacetylases in Lung Endothelial Pathobiology

A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and, as such, provides a semi-selective barrier between the blood and the interstitial space. Compromise of the lung EC barrier due to inflammatory or toxic events may result in pulmonary edema, which is a cardinal feature of acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS). The EC functions are controlled, at least in part, via epigenetic mechanisms mediated by histone deacetylases (HDACs). Zinc-dependent HDACs represent the largest group of HDACs and are activated by Zn2+. Members of this HDAC group are involved in epigenetic regulation primarily by modifying the structure of chromatin upon removal of acetyl groups from histones. In addition, they can deacetylate many non-histone histone proteins, including those located in extranuclear compartments. Recently, the therapeutic potential of inhibiting zinc-dependent HDACs for EC barrier preservation has gained momentum. However, the role of specific HDAC subtypes in EC barrier regulation remains largely unknown. This review aims to provide an update on the role of zinc-dependent HDACs in endothelial dysfunction and its related diseases. We will broadly focus on biological contributions, signaling pathways and transcriptional roles of HDACs in endothelial pathobiology associated mainly with lung diseases, and we will discuss the potential of their inhibitors for lung injury prevention.

Discontinuation of Levetiracetam and Valproic Acid Due to Adverse Effects in Early Post-traumatic Seizure Prophylaxis

INTRODUCTION

Levetiracetam (LEV) and valproic acid (VPA) are two anti-epileptic drugs (AEDs) routinely used for post-traumatic seizure (PTS) prophylaxis at our institution. In our practice, VPA is used for its beneficial effects on behavioral agitation and headaches, but it is also associated with abnormal liver function tests (LFTs). Both medications may be associated with thrombocytopenia. There is less literature comparing the adverse effect profiles and discontinuation rates of LEV and VPA in the context of PTS prophylaxis. We conducted a quality improvement (QI) analysis to determine the safety of LEV and VPA for traumatic brain injury (TBI) patients at our institution. In particular, our QI analysis involved calculating the rates of discontinuation or change of drug regimen due to the adverse effects.

METHODS

Our QI analysis focused on patients treated for TBI at our institution during a six-year period. We recorded the AED used and if the AED was discontinued or switched due to thrombocytopenia, behavioral agitation, headaches, or elevated LFTs (including elevated aspartate aminotransferase or alanine aminotransferase values). We also recorded the incidence of early PTS, defined as seizures within seven days of the TBI.

RESULTS

Our QI analysis included patients with a mean age of approximately 49 years with nearly 75% males. The mean Glasgow Coma Scale (GCS) score was 12.88, with 73.11% of patients having a mild GCS. The three leading injury mechanisms were fall, assault, and motor vehicle collision. The three leading types of TBI were traumatic subarachnoid hemorrhage, subdural hematoma, and cerebral contusion. Among patients with no prior history of seizures, we found an early PTS incidence of 7.28%. For patients administered LEV and VPA, 0.11% (1/898) and 3.85% (4/104) had the medication discontinued or changed because of thrombocytopenia (p < 0.001), respectively. For patients on LEV, 4.01% (36/898) and 1.78% (16/898) had the medication discontinued or changed because of behavioral agitation and headaches, respectively. For patients on VPA, 2.88% (3/104) had the medication discontinued or changed because of hepatotoxicity. In total, 5.90% versus 6.73% (p > 0.5) of patients on LEV and VPA, respectively, had their medication regimens changed due to the adverse effects.

CONCLUSIONS

The incidence of early PTS in our patients is within the range of what has been reported in the literature. The rate of discontinuation of LEV and VPA on account of adverse events is low in the context of PTS prophylaxis. Both medications had similar overall rates of discontinuation. VPA was discontinued more frequently than LEV due to thrombocytopenia, but discontinuation was not common in either case. LEV is associated with behavioral agitation and headaches, which makes VPA a desirable alternative for patients suffering from these symptoms.

Effects of valproic acid on syncytialization in human placental trophoblast cell lines

The placenta is a critical organ for fetal development and a healthy pregnancy, and has multifaceted functions (e.g., substance exchange and hormone secretion). Syncytialization of trophoblasts is important for maintaining placental functions. Epilepsy is one of the most common neurological conditions worldwide. Therefore, this study aimed to reveal the influence of antiepileptic drugs, including valproic acid (VPA), carbamazepine, lamotrigine, gabapentin, levetiracetam, topiramate, lacosamide, and clobazam, at clinically relevant concentrations on syncytialization using in vitro models of trophoblasts. To induce differentiation into syncytiotrophoblast-like cells, BeWo cells were treated with forskolin. Exposure to VPA was found to dose-dependently influence syncytialization-associated genes (ERVW-1, ERVFRD-1, GJA1, CGB, CSH, SLC1A5, and ABCC4) in differentiated BeWo cells. Herein, the biomarkers between differentiated BeWo cells and the human trophoblast stem model (TSCT) were compared. In particular, MFSD2A levels were low in BeWo cells but abundant in TSCT cells. VPA exposure affected the expression of ERVW-1, ERVFRD-1, GJA1, CSH, MFSD2A, and ABCC4 in differentiated cells (ST-TSCT). Furthermore, VPA exposure attenuated BeWo and TSCT cell fusion. Finally, the relationships between neonatal/placental parameters and the expression of syncytialization markers in human term placentas were analyzed. MFSD2A expression was positively correlated with neonatal body weight, head circumference, chest circumference, and placental weight. Our findings have important implications for better understanding the mechanisms of toxicity of antiepileptic drugs and predicting the risks to placental and fetal development.

Real-World Effectiveness and Safety of Direct-Acting Antivirals in Patients with Chronic Hepatitis C and Epilepsy: An Epi-Ter-2 Study in Poland

INTRODUCTION

In Poland, active HCV infection affects between 0.4 and 0.5% of the population, i.e., about 150,000 people, while the number of patients with epilepsy is estimated to be 350,000-400,000. Currently available antiviral therapies show little interaction with neurological drugs. The aim of our study was to evaluate the effectiveness and safety of the treatment of chronic HCV infection in patients with coexisting epilepsy.

METHODS

A total of 184 epilepsy patients were selected from the group of 10,152 HCV-infected patients treated for HCV infection within the Epiter-2 database from 2015 to 2018. Comparing the effectiveness and safety of anti-HCV regimens between the patients with comorbid epilepsy and 3573 patients without comorbidities was our study's objective.

RESULTS

The effectiveness of anti-HCV treatment was high in both the sample and the control group. No statistically significant SVR difference was observed between the sample group, with ITT = 93.5% and mITT = 95.5%, and the control group, with ITT = 95.2% and mITT = 97.5%, regardless of the genotype and the stage of liver disease at the start of therapy. The treatment was safe in patients with epilepsy.

CONCLUSIONS

The effectiveness and safety of HCV treatment in patients with epilepsy are comparable to those of patients with no significant comorbidities.

Quantitative systems pharmacology Model to characterize valproic acid-induced hyperammonemia and the effect of L-carnitine supplementation

Valproic acid (VPA) is a short-chain fatty acid widely prescribed in the treatment of seizure disorders and epilepsy syndromes, although its therapeutic value may be undermined by its toxicity. VPA serious adverse effects are reported to have a significant and dose-dependent incidence, many associated with VPA-induced hyperammonemia. This effect has been linked with reduced levels of carnitine; an endogenous compound involved in fatty acid's mitochondrial β-oxidation by facilitation of its entrance via the carnitine shuttle. High exposure to VPA can lead to carnitine depletion causing a misbalance between the intra-mitochondrial β-oxidation and the microsomal ω-oxidation, a pathway that produces toxic metabolites such as 4-en-VPA which inhibits ammonia elimination. Moreover, a reduction in carnitine levels might be also related to VPA-induced obesity and lipids disorder. In turn, L-carnitine supplementation (CS) has been recommended and empirically used to reduce VPA's hepatotoxicity. The aim of this work was to develop a Quantitative Systems Pharmacology (QSP) model to characterize VPA-induced hyperammonemia and evaluate the benefits of CS in preventing hyperammonemia under both chronic treatment and after VPA overdosing. The QSP model included a VPA population pharmacokinetics model that allowed the prediction of total and unbound concentrations after single and multiple oral doses considering its saturable binding to plasma proteins. Predictions of time courses for 2-en-VPA, 4-en-DPA, VPA-glucuronide, carnitine, ammonia and urea levels, and for the relative change in fatty acids, Acetyl-CoA, and glutamate reflected the VPA induced changes and the efficacy of the treatment with L-carnitine. The QSP model was implemented to give a rational basis for the L-carnitine dose selection to optimize CS depending on VPA dosage regime and to assess the currently recommended L-carnitine rescue therapy after VPA overdosing. Results show that a L-carnitine dose equal to the double of the VPA dose using the same interdose interval would maintain the ammonia levels at baseline. The QSP model may be expanded in the future to describe other adverse events linked to VPA-induced changes in endogenous compounds.

Embryonic exposure to acetyl-L-carnitine protects against valproic acid-induced cardiac malformation in zebrafish model

Worldwide, estimated counts of about 7.9 million children are born with serious birth defects. In addition to genetic factors, prenatal exposure to drugs and environmental toxicants represents a major contributing factor to congenital malformations. In earlier investigation, we explored cardiac malformation caused by valproic acid (VPA) during early developing stages of zebrafish. Since heart depends on mitochondrial fatty acid oxidative metabolism for energy demands in which carnitine shuttle has a major role, the present study aimed to investigate the effect of acetyl-L-carnitine (AC) against VPA-induced cardiac malformation in developing zebrafish. Initially, AC was subjected to toxicological evaluation, and two micromolar concentrations (25 µM and 50 µM) were selected for evaluation. A sub-lethal concentration of VPA (50 µM) was selected to induce cardiac malformation. The embryos were grouped and the drug exposures were made at 2.5 h post-fertilization (hpf). The cardiac development and functioning was monitored. A progressive decline in cardiac functioning was noted in group exposed to VPA 50 µM. At 96 hpf and 120 hpf, the morphology of heart was severely affected with the chambers which became elongated and string-like accompanied by histological changes. Acridine orange staining showed accumulation of apoptotic cells. Group exposed to VPA 50 µM with AC 50 µM showed a significant reduction in pericardial sac edema with morphological, functional and histological recovery in developing heart. Moreover, reduced number of apoptotic cells was noted. The improvement with AC might be due to restoration of carnitine homeostasis for cardiac energy metabolism in developing heart.

Determination of valproic acid and its six metabolites in human serum using LC-MS/MS and application to interaction with carbapenems in epileptic patients

Valproic acid (VPA) is a classic medication for several types of epilepsy and mood disorders, and some of its effectiveness and toxicity is associated with metabolites. Although many reports have reported the drug-drug interactions of VPA, no study has focused on the influence of carbapenems (CBPMs) on VPA's active metabolites. An LC-MS/MS method for determining VPA and its six metabolites (3-hydroxy valproic acid, 4-hydroxy valproic acid, 2-propyl-2-pentenoic acid, 2-propyl-4-pentenoic acid, 3-keto valproic acid, and 2-propylglutaric acid) in human serum was established and applied to evaluate the drug-drug interaction with CBPMs in epileptic patients. The stable isotope valproic acid-d6 was used as an internal standard. Analytes in serum samples (50 μl) were isolated using a Kinetex C₁₈ column (3 × 100 mm, 2.6 μm) and detected via negative electrospray ionization after protein precipitation. It was linear (r > 0.99) over the calibration range for different analytes. The accuracy was 91.44-110.92%, and the precision was less than 9.98%. The matrix effect, recovery, and stability met the acceptance criteria. According to the data collected from 150 epileptic patients, the concentration-dose ratio for VPA and its metabolites decreased with CBPM polytherapy. This method is simple and rapid with great accuracy and precision. It is suitable for routine clinical analysis of VPA and its metabolites in human serum.

Therapeutic and Toxic Effects of Valproic Acid Metabolites

Valproic acid (VPA) and its salts are psychotropic drugs that are widely used in neurological diseases (epilepsy, neuropathic pain, migraine, etc.) and psychiatric disorders (schizophrenia, bipolar affective disorder, addiction diseases, etc.). In addition, the indications for the appointment of valproate have been expanding in recent years in connection with the study of new mechanisms of action of therapeutic and toxic metabolites of VPA in the human body. Thus, VPA is considered a component of disease-modifying therapy for multiple tumors, neurodegenerative diseases (Huntington's disease, Parkinson's disease, Duchenne progressive dystrophy, etc.), and human immunodeficiency syndrome. The metabolism of VPA is complex and continues to be studied. Known pathways of VPA metabolism include: β-oxidation in the tricarboxylic acid cycle (acetylation); oxidation with the participation of cytochrome P-450 isoenzymes (P-oxidation); and glucuronidation. The complex metabolism of VPA explains the diversity of its active and inactive metabolites, which have therapeutic, neutral, or toxic effects. It is known that some active metabolites of VPA may have a stronger clinical effect than VPA itself. These reasons explain the relevance of this narrative review, which summarizes the results of studies of blood (serum, plasma) and urinary metabolites of VPA from the standpoint of the pharmacogenomics and pharmacometabolomics. In addition, a new personalized approach to assessing the cumulative risk of developing VPA-induced adverse reactions is presented and ways for their correction are proposed depending on the patient's pharmacogenetic profile and the level of therapeutic and toxic VPA metabolites in the human body fluids (blood, urine).

Elevated Anion Gap Metabolic Acidosis With High Osmolar Gap and Increased Serum Acetone Level: A Case Report

Acetone poisoning, although not very common, can present with varied signs and symptoms. High acetone levels in serum can be due to exogenous exposure or endogenous production of acetone. Unlike certain alcohol toxicities, acetone does not cause high anion gap metabolic acidosis.

A 69-year-old male presented to our service with shock and acute encephalopathy and required intensive care support. Initial laboratory investigation showed high anion gap metabolic acidosis with high osmolar gap. Serum acetone level was elevated. Clinicians need to be aware of how to elucidate such metabolic disturbances and associated toxicities.

Management and Associated Toxicokinetics of Massive Valproic Acid Ingestion with High Flow Continuous Venovenous Hemodiafiltration

INTRODUCTION

Valproic acid (VPA) toxicity commonly results in a self-limited state of CNS depression that is managed with supportive care and levocarnitine. In massive overdose, patients can develop toxic encephalopathy, shock, multisystem organ failure, and death. We present a case with relevant toxicokinetics of a patient presenting with a profoundly elevated VPA concentration resulting in survival, treated with supportive care including high-dose continuous venovenous hemodiafiltration (CVVHDF).

CASE REPORT

A 17-year-old female presented to an emergency department after being found unresponsive at home with concern for massive VPA ingestion. She arrived obtunded and hypotensive with initial VPA concentration of 2226 mg/L, estimated 9 h post-ingestion. Her early hospital course was marked by hypotension requiring multiple vasopressors, and her workup was notable for multiple severe metabolic derangements. High-dose CVVHDF was initiated upon transfer to a tertiary children's hospital with the aim to enhance VPA removal and normalize metabolic derangements. At that time, her VPA concentration was 1071 mg/L. Apparent half-life of VPA improved modestly with extracorporeal treatment, but her metabolic derangements and hemodynamic instability corrected rapidly. Her clinical course was complicated by necrotizing pancreatitis, pancytopenia requiring transfusions of multiple cell lines, coma, and seizures. She ultimately recovered with normal neurological function.

Meropenem to Treat Valproic Acid Intoxication

ABSTRACT

This therapeutic drug monitoring (TDM) grand round describes a patient with serious valproic acid intoxication. A total valproic acid level of 844 mg/L and an unbound valproic acid level of 604 mg/L were observed. Meropenem was administered to enhance the clearance of valproic acid. This off-label usage of meropenem is based on the drug-drug interaction between carbapenems and valproic acid, which reduced the level of valproic acid within 24 hours after administration.

L-carnitine does not improve valproic acid poisoning management: a cohort study with toxicokinetics and concentration/effect relationships

Background

Valproic acid (VPA) poisoning is responsible for life-threatening neurological and metabolic impairments. Despite only low-level evidence of effectiveness, L-carnitine has been used for years to prevent or reverse VPA-related toxicity. We aimed to evaluate the effects of L-carnitine used to treat acute VPA poisoning on the time-course of plasma VPA concentrations and VPA-related toxicity. We designed a single-center cohort study including all VPA-poisoned patients admitted to the intensive care unit. We studied VPA toxicokinetics using a nonlinear mixed-effects model-based population approach and modeled individual plasma VPA/blood lactate concentration relationships. Then, we evaluated L-carnitine-attributed effects by comparing VPA elimination half-lives and time-courses of blood lactate levels and organ dysfunction [assessed by the Sequential Organ Failure Assessment (SOFA) score] between matched L-carnitine-treated and non-treated patients using a multivariate analysis including a propensity score.

Results

Sixty-nine VPA-poisoned patients (40F/29 M; age, 41 years [32–47]) (median [25th–75th percentiles]; SOFA score, 4 [1–6]) were included. The presumed VPA ingested dose was 15 g [10–32]. Plasma VPA concentration on admission was 231 mg/L [147–415]. The most common manifestations were coma (70%), hyperlactatemia (3.9 mmol/L [2.7–4.9]) and hyperammonemia (127 mmol/L [92–159]). VPA toxicokinetics well fitted a one-compartment linear model with a mean elimination half-life of 22.9 h (coefficient of variation, 28.1%). Plasma VPA (C)/blood lactate concentration (E) relationships were well described by an exponential growth equation [\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$E={E}_{0}\times {e}^{k\cdot C}$$\end{document}E=E0×ek·C; with baseline E₀ = 1.3 mmol/L (43.9%) and rate constant of the effect, k = 0.003 L/mg (59.5%)]. Based on a multivariate analysis, peak blood lactate concentration was the only factor independently associated with L-carnitine administration (odds ratio, 1.9, 95% confidence interval, 1.2–2.8; P = 0.004). We found no significant contribution of L-carnitine to enhancing VPA elimination, accelerating blood lactate level normalization and/or preventing organ dysfunction.

Conclusions

VPA poisoning results in severe toxicity. While L-carnitine does not contribute to enhancing VPA clearance, its impact on accelerating blood lactate level normalization and/or preventing organ dysfunction remains uncertain. Investigating VPA toxicokinetics and concentration/effect relationships may help understanding how to improve VPA-poisoned patient management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-00984-z.

Case Report: A Case of Valproic Acid-Induced Hyperammonemic Encephalopathy Associated With the Initiation of Lithium: A Re-duplicable Finding

INTRODUCTION

Hyperammonemic encephalopathy (HAE) is a serious adverse effect of valproate semisodium, which is facilitated by the potential for drug interaction. However, despite frequent co-prescription of valproate semisodium and lithium, the role of this combination in the occurrence of HAE has not been defined in the literature. This case report concerns the occurrence of HAE concomitant with the initiation of lithium in a 29-year-old patient who had been placed on valproate semisodium for a schizoaffective disorder.

CASE REPORT

Due to a relapse while on a combined antipsychotic and mood-stabilizing therapy (paliperidone palmitate and valproate semisodium), a cross-taper from valproate semisodium to lithium was proposed. The initiation of lithium was accompanied by an acute confusional syndrome, an elevated serum valproate level and hyperammonemia suggestive of drug-induced HAE. The discontinuation of lithium and reduction of valproate semisodium led to neurological improvement, until a recrudescence of psychiatric symptoms justified a rechallenge of the combination within the framework of a new cross-taper. As soon as Lithium was re-initiated, an increase in the serum valproate level and hyperammonemia were again noted.

DISCUSSION

The mechanisms of valproate-related HAE involve various metabolic pathways. In this case, exploration of the iatrogenic hypothesis focused on the imputability of concomitant cannabis use and co-prescriptions of benzodiazepines, antipsychotics, and in all likelihood, mood stabilizers.

CONCLUSION

Therefore, this case study suggests that Lithium plays a role in serum valproate level elevation, and supports the hypothesis of an association between an elevated serum valproate level, hyperammonemia and reversible encephalopathy. A more in-depth pharmacokinetic exploration would provide a better understanding of the mechanisms of these interactions and support for the benefit-risk balance associated with this frequent co-prescription.

Hyperammonemia during treatment with valproate in critically ill patients

INTRODUCTION

Hyperammonemia (HA) is a potential side-effect of valproate (VPA) treatment, which has been described during long-term administration. The aim of this study was to evaluate the incidence, the impact and the risk factors of HA in critically ill patients.

METHODS

We reviewed the data of all adult patients treated in our mixed 35-bed Department of Intensive Care over a 12-year period (2004-2015) who: a) were treated with VPA for more than 72 h and b) had at least one measurement of ammonium and VPA levels during the ICU stay; patients with Child-Pugh C liver cirrhosis were excluded. HA was defined as ammonium levels above 60 μg/dl.

RESULTS

Of a total of 2640 patients treated with VPA, 319 patients met the inclusion criteria (median age 64 years; male gender 55%); 78% of them were admitted for neurological reasons and ICU mortality was 30%. Median ammonium levels were 88 [63-118] µg/dl. HA was found in 245 (77%) patients. For those patients with HA, median time from start of VPA therapy to HA was 3 [2-5] days. In a multivariable analysis, high VPA serum levels, mechanical ventilation and sepsis were independently associated with HA during VPA therapy. In 98/243 (40%) of HA patients, VPA was interrupted; VPA interruption was more frequent in patients with ammonium levels > 100 μg/dl than others (p = 0.001). HA was not an independent predictor of ICU mortality or poor neurological outcome.

CONCLUSIONS

In this study, HA was a common finding during treatment with VPA in acutely ill patients. VPA levels, sepsis and mechanical ventilation were risk factors for HA. Hyperammonemia did not influence patients' outcome.

Reactive metabolites of the anticonvulsant drugs and approaches to minimize the adverse drug reaction

Several generations of antiepileptic drugs (AEDs) are available in the market for the treatment of seizures, but these are amalgamated with acute to chronic side effects. The most common side effects of AEDs are dose-related, but some are idiosyncratic adverse drug reactions (ADRs) that transpire due to the formation of reactive metabolite (RM) after the bioactivation process. Because of the adverse reactions patients usually discontinue the medication in between the treatment. The AEDs such as valproic acid, lamotrigine, phenytoin etc., can be categorized under such types because they form the RM which may prevail with life-threatening adverse effects or immune-mediated reactions. Hepatotoxicity, teratogenicity, cutaneous hypersensitivity, dizziness, addiction, serum sickness reaction, renal calculi, metabolic acidosis are associated with the metabolites of drugs such as arene oxide, N-desmethyldiazepam, 2-(1-hydroxyethyl)-2-methylsuccinimide, 2-(sulphamoy1acetyl)-phenol, E-2-en-VPA and 4-en-VPA and carbamazepine-10,11-epoxide, etc. The major toxicities are associated with the moieties that are either capable of forming RM or the functional groups may itself be too reactive prior to the metabolism. These functional groups or fragment structures are typically known as structural alerts or toxicophores. Therefore, minimizing the bioactivation potential of lead structures in the early phases of drug discovery by a modification to low-risk drug molecules is a priority for the pharmaceutical companies. Additionally, excellent potency and pharmacokinetic (PK) behaviour help in ensuring that appropriate (low dose) candidate drugs progress into the development phase. The current review discusses about RMs in the anticonvulsant drugs along with their mechanism vis-a-vis research efforts that have been taken to minimize the toxic effects of AEDs therapy.

Microtubule associated proteins as targets for anticancer drug development

The dynamic equilibrium of tubulin-microtubule is an essential aspect of cell survivality. Modulation of this dynamics has become an important target for the cancer drug development. Tubulin exists in the alpha-beta dimer form which polymerizes to form microtubule and further depolymerizes back to tubulin dimer. The microtubule plays an essential role in mitosis and cell multiplication. Antitubulin drugs disturb the microtubule dynamics which is essentially required for DNA segregation and cell division during mitosis so killing the cancerous cells. Microtubule Associated Proteins (MAPs) interact with cellular cytoskeletal microtubules. MAPs bind to the either polymerized or depolymerized tubulin dimers within the cell and mostly causing stabilization of microtubules. Some of the tubulin binding drugs are in clinical use and others in clinical trial. MAPs inhibitors are also in clinical trial. Post-translational modification of lysine-40 either in histone or in alpha tubulin has an important role in gene expression and is balanced between histone deacetylases (HDACs) and histone acetyltransferases (HATs). HDAC inhibitors have the anticancer properties to form a drug for the treatment of cancer. They act by inducing cell cycle arrest and cell death. Some of the HDAC inhibitors are approved to be used as anticancer drug while others are under different phases of clinical trial. The present review updates on various MAPs, their role in cancer progression, MAPs inhibitors and their future prospects.

Valproic acid inhibits chronic Toxoplasma infection and associated brain inflammation in mice

Individuals infected with Toxoplasma gondii (T. gondii) are prone to psycho-behavioral disorders, most notably schizophrenia and bipolar. Valproic acid reportedly inhibited the proliferation of T. gondii tachyzoites in vitro. However, animals treated with the drug neither lived longer during acute infection nor had fewer brain cysts upon chronic infection. In this study, a quantitative real-time PCR (qPCR) method was applied to quantify copy numbers of BAG1 (a bradyzoite-specific protein), REP529 DNA (a repetitive DNA fragment of the parasite), and SAG1 (a highly expressed tachyzoite-specific surface protein) in brains of chronically infected mice treated by valproic acid. The treatment inhibited the infection and decreased BAG1, SAG1, and REP529 copy numbers in mice brains (P < 0.0001), comparable to Trimethoprim/Sulfamethoxazole (TMP/SMZ), the common medication for Toxoplasmosis treatment. Moreover, valproic acid decreased brain TNF-α expression (P < 0.0001), comparable to TMP/SMZ. Histological examination of mice brains showed a marked reduction in cyst establishment, perivascular infiltration of lymphocytes, and glial nodules to the same level as the TMP/SMZ group. Our results provide direct evidence for the efficacy of valproic acid, a mood-stabilizing and antipsychotic drug against chronic Toxoplasma infection. These results might help modulate therapeutic regimens for neuropsychiatric patients and design more effective anti-Toxoplasma drugs.

Instantaneous Differentiation of Functional Isomers via Reactive Flowing Atmospheric Pressure Afterglow Mass Spectrometry

Ambient mass spectrometry (AMS) allows direct desorption and ionization of analytes in real time with minimal-to-no sample preparation. However, it may present inadequate capabilities for differentiating isomers. Here, a reactive flowing atmospheric-pressure afterglow (reactive-FAPA) AMS source is developed for rapid isomer differentiation by derivatization of analytes in real time. The effects of the reactive-FAPA operating conditions on the reagent and product ions were studied and optimized for highly volatile and non-volatile model compounds with different carbonyl functional groups. In addition, two functional isomers of valproic acid (VPA) metabolites, 4-ene VPA and γ-valprolactone, are successfully differentiated for the first time by incorporating methylamine (MA) reagent vapor into the plasma effluent used for desorption/ionization. Reactive-FAPAMS for 4-ene VPA shows only detectable peaks of the protonated acylation product [M + MA-H₂O + H]⁺, while for γ-valprolactone, it shows detectable peaks for both protonated acylation product [M + MA-H₂O + H]⁺ and protonated intermediate [M + MA + H]⁺. A method for quantitative characterization of mixtures of 4-ene VPA and γ-valprolactone is also developed and validated. In addition, reactive-FAPAMS also shows better detection sensitivity compared to nonreactive-FAPAMS for some larger analyte types, such as UV filters and steroids. The limit of detection (LOD) of pregnenolone acetate in reactive-FAPAMS is 310 ng/mL, which is about 10 times better than its LOD in nonreactive-FAPA.

Megaesophagus and Megaduodenum Found Incidentally on a Routine Chest Radiograph During a Health Examination

Chronic idiopathic intestinal pseudo-obstruction (CIIP) caused by impaired intestinal peristalsis leads to intestinal obstructive symptoms. A 20-year-old man had marked esophageal dilatation that was found incidentally on chest radiography during a health examination. Chest/abdominal contrast-enhanced computed tomography and endoscopy showed marked esophageal and duodenal dilatation without mechanical obstruction. Upper gastrointestinal series and high-resolution esophageal manometry revealed absent peristalsis in the dilated part. CIIP was suspected in the patient's father, suggesting familial CIIP. The patient likely had signs of pre-onset CIIP. This is the first case of suspected CIIP in which detailed gastrointestinal tract examinations were performed before symptoms appeared.

Toxicology of Psychoactive Substances

A trend in the increasing use of prescription psychoactive drugs (PADs), including antidepressants, antipsychotics, and mood stabilizers, has been reported in the United States and globally. In addition, there has been an increase in the production and usage of illicit PADs and emergence of new psychoactive substances (NPSs) all over the world. PADs pose unique challenges for critical care providers who may encounter toxicology issues due to drug interactions, side effects, or drug overdoses. This article provides a summary of the toxicologic features of commonly used and abused PADs: antidepressants, antipsychotics, mood stabilizers, hallucinogens, NPSs, caffeine, nicotine, and cannabis.

Histone Deacetylase 7 Inhibition in a Murine Model of Gram-Negative Pneumonia-Induced Acute Lung Injury

BACKGROUND

Pulmonary infections remain the most common cause of Acute Respiratory Distress Syndrome (ARDS), a pulmonary inflammatory disease with high mortality, for which no targeted therapy currently exists. We have previously demonstrated an ameliorated syndrome with early, broad spectrum Histone Deacetylase (HDAC) inhibition in a murine model of gram-negative pneumonia-induced Acute Lung Injury (ALI), the underlying pulmonary pathologic phenotype leading to ARDS. With the current project we aim to determine if selective inhibition of a specific HDAC leads to a similar pro-survival phenotype, potentially pointing to a future therapeutic target.

METHODS

C57Bl/6 mice underwent endotracheal instillation of 30×10Escherichia coli (strain 19138) versus saline (n = 24). Half the infected mice were administered Trichostatin A (TSA) 30 min later. All animals were sacrificed 6 h later for tissue sampling and HDAC quantification, while another set of animals (n = 24) was followed to determine survival. Experiments were repeated with selective siRNA inhibition of the HDAC demonstrating the greatest inhibition versus scrambled siRNA (n = 24).

RESULTS

TSA significantly ameliorated the inflammatory phenotype and improved survival in infected-ALI mice, and HDAC7 was the HDAC with the greatest transcription and protein translation suppression. Similar results were obtained with selective HDAC7 siRNA inhibition compared with scrambled siRNA.

CONCLUSION

HDAC7 appears to play a key role in the inflammatory response that leads to ALI after gram-negative pneumonia in mice.

[Cardiac arrest under special circumstances]

These guidelines of the European Resuscitation Council (ERC) Cardiac Arrest under Special Circumstances are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required for basic and advanced life support for the prevention and treatment of cardiac arrest under special circumstances; in particular, specific causes (hypoxia, trauma, anaphylaxis, sepsis, hypo-/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), specific settings (operating room, cardiac surgery, cardiac catheterization laboratory, dialysis unit, dental clinics, transportation [in-flight, cruise ships], sport, drowning, mass casualty incidents), and specific patient groups (asthma and chronic obstructive pulmonary disease, neurological disease, morbid obesity, pregnancy).

Hyperammonemia in acetaminophen toxicity

INTRODUCTION

Acetaminophen-induced hepatotoxicity can result in hyperammonemia, but it is not clear if elevated ammonia concentrations predict encephalopathy.

METHODS

We retrospectively studied patients with acetaminophen toxicity at a liver transplant center over 8 years (January 1, 2010-December 31, 2017), who developed hepatotoxicity (AST and/or ALT >1000 IU/L) or hyperammonemia (ammonia > 40 µmol/L). We recorded baseline characteristics, laboratory data, documented grade of encephalopathy, and treatments administered. Sensitivity and specificity values were calculated for varying ammonia concentrations.

RESULTS

A total of 102 patient encounters were included with 75 having ammonia concentrations. On presentation, 40% (30/75) of patients had concentrations greater than 100 µmol/L. However, an [ammonia] > 100 µmol/L was neither sensitive (46 % [95% CI: 26-67%]) nor specific (63% [48 - 76%]) for encephalopathy. Only an increasing ammonia concentration had a significant, but small (1.53 (95% CI: 1.06 - 2.20)) positive likelihood ratio for the development of hepatic encephalopathy.

DISCUSSION

Animal models have suggested that in acetaminophen toxicity, encephalopathy may be secondary to an alternative mechanism other than hyperammonemia which may explain the lack of correlation between initial hyperammonemia and encephalopathy in this cohort. Additionally, a lack of empiric treatment for hyperammonemia did not appear to alter the course of any of the patients. None of these patients developed encephalopathy.

CONCLUSION

In cases of acetaminophen-induced hepatotoxicity, ammonia concentrations do not correlate with encephalopathy and empiric treatment for hyperammonemia does not appear to be beneficial.

Antioxidant and anti-inflammatory properties of alpha-lipoic acid protect against valproic acid-induced liver injury

Valproic acid (VPA) is one of the most used antiepileptic drugs despite of its many adverse effects such as anemia, leucopenia, thrombocytopenia, and liver toxicity. The hepatoprotective effect of alpha-lipoic acid (ALA) was confirmed. The aim of this study was to detect the protective effect of ALA against the adverse effects of VPA. To study this, 30 white albino Wistar male rats were divided into four groups. Group I was the control group; Group II included rats that received ALA (100 mg·kg-1·day-1) orally for 14 days; Group III and Group IV included rats that received VPA (500 mg·kg-1·day-1) for 15 days intraperitoneally, but Group IV rats received ALA (100 mg·kg-1·day-1) orally for 14 days prior to VPA. Blood samples were collected and livers were excised from rats for colorimetric analysis and quantitative real-time PCR. The rats that received VPA showed leucopenia, thrombocytopenia, a significant decrease of superoxide dismutase, glutathione, nuclear factor erythroid 2-related factor 2, and sirtuin 1, besides a significant increase of malondialdehyde and tumor necrosis factor α. Prior treatment with ALA prevented all these results; ALA protected against VPA-induced liver damage and hematological disturbance via antioxidant and anti-inflammatory properties.

Ferulic Acid Induces Keratin 6α via Inhibition of Nuclear β-Catenin Accumulation and Activation of Nrf2 in Wound-Induced Inflammation

Injured tissue triggers complex interactions through biological process associated with keratins. Rapid recovery is most important for protection against secondary infection and inflammatory pain. For rapid wound healing with minimal pain and side effects, shilajit has been used as an ayurvedic medicine. However, the mechanisms of rapid wound closure are unknown. Here, we found that shilajit induced wound closure in an acute wound model and induced migration in skin explant cultures through evaluation of transcriptomics via microarray testing. In addition, ferulic acid (FA), as a bioactive compound, induced migration via modulation of keratin 6α (K6α) and inhibition of β-catenin in primary keratinocytes of skin explant culture and injured full-thickness skin, because accumulation of β-catenin into the nucleus acts as a negative regulator and disturbs migration in human epidermal keratinocytes. Furthermore, FA alleviated wound-induced inflammation via activation of nuclear factor erythroid-2-related factor 2 (Nrf2) at the wound edge. These findings show that FA is a novel therapeutic agent for wound healing that acts via inhibition of β-catenin in keratinocytes and by activation of Nrf2 in wound-induced inflammation.

European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances

These European Resuscitation Council (ERC) Cardiac Arrest in Special Circumstances guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required to basic and advanced life support for the prevention and treatment of cardiac arrest in special circumstances; specifically special causes (hypoxia, trauma, anaphylaxis, sepsis, hypo/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), special settings (operating room, cardiac surgery, catheter laboratory, dialysis unit, dental clinics, transportation (in-flight, cruise ships), sport, drowning, mass casualty incidents), and special patient groups (asthma and COPD, neurological disease, obesity, pregnancy).

Thinking out of the box: management of valproic acid toxicity with carbapenems

Valproic acid (VPA) is commonly used medication to treat seizure disorder and as prophylaxis for bipolar disorder. Acute VPA toxicity can cause varied symptoms ranging from mild drowsiness to severe cerebral oedema and coma. The therapeutic level of VPA is around 50-100 µg/mL and most of it is protein bound. It is mainly metabolised by liver and is eliminated via bile. The metabolites of VPA interfere with urea cycle and cause deficiency in carnitine leading to increase in ammonia levels. The use of carnitine to treat VPA toxicity is well known but it is still unclear if it lowers VPA levels. We report a case of VPA toxicity that did not respond to use of carnitine at 6000 mg orally but was successfully treated using meropenem leading to lowering of VPA levels and also clinical improvement of patient.

Cedrus atlantica Extract Suppress Glioblastoma Growth through Promotion of Genotoxicity and Apoptosis: In Vitro and In Vivo Studies

Glioblastoma (GBM) is the most common malignant primary brain tumor in humans, exhibiting highly infiltrative growth and drug resistance to conventional chemotherapy. Cedrus atlantica (CAt) extract has been shown to decrease postoperative pain and inhibit the growth of K562 leukemia cells. The aim of this study was to assess the anti-GBM activity and molecular mechanism of CAt extract in vitro and in vivo. The results showed that CAt extract greatly suppressed GBM cells both in vitro and in vivo and enhanced the survival rate in subcutaneous and orthotopic animal models. Moreover, CAt extract increased the level of ROS and induced DNA damage, resulting in cell cycle arrest at the G₀/G₁ phase and cell apoptosis. Western blotting results indicated that CAt extract regulates p53/p21 and CDK4/cyclin D1 protein expression and activates extrinsic and intrinsic apoptosis. Furthermore, CAt extract enhanced the cytotoxicity of Temozolomide and decreased AKT/mTOR signaling by combination treatment. In toxicity assays, CAt extract exhibited low cytotoxicity toward normal cells or organs in vitro and in vivo. CAt extract suppresses the growth of GBM by induction of genotoxicity and activation of apoptosis. The results of this study suggest that CAt extract can be developed as a therapeutic agent or adjuvant for GBM treatment in the future.

Management of status epilepticus in patients with liver or kidney disease: a narrative review

Introduction: Status epilepticus (SE) is a neurologic and medical emergency with significant related morbidity and mortality. Hepatic or renal dysfunction can considerably affect the pharmacokinetics of drugs used for SE through a variety of direct or indirect mechanisms.Areas Covered: This review aims to focus on the therapeutic management of SE in patients with hepatic or renal impairment, highlighting drugs' selection and dose changes that may be necessary due to altered drug metabolism and excretion. The references for this review were identified by searches of PubMed and Google Scholar until May 2020.Expert opinion: According to literature evidence and clinical experience, in patients with renal disease, the authors suggest considering lorazepam as the drug of choice in pre-hospital and intra-hospital early-stage SE, phenytoin in definite SE, propofol in refractory or super-refractory SE. In patients with liver disease, the authors suggest the use of lorazepam as drug of choice in pre-hospital and intra-hospital early-stage SE, lacosamide in definite SE, propofol in refractory or super-refractory SE. A list of preferred drugs for all SE stages is provided.

Kinetic modeling of stem cell transcriptome dynamics to identify regulatory modules of normal and disturbed neuroectodermal differentiation

Thousands of transcriptome data sets are available, but approaches for their use in dynamic cell response modelling are few, especially for processes affected simultaneously by two orthogonal influencing variables. We approached this problem for neuroepithelial development of human pluripotent stem cells (differentiation variable), in the presence or absence of valproic acid (signaling variable). Using few basic assumptions (sequential differentiation states of cells; discrete on/off states for individual genes in these states), and time-resolved transcriptome data, a comprehensive model of spontaneous and perturbed gene expression dynamics was developed. The model made reliable predictions (average correlation of 0.85 between predicted and subsequently tested expression values). Even regulations predicted to be non-monotonic were successfully validated by PCR in new sets of experiments. Transient patterns of gene regulation were identified from model predictions. They pointed towards activation of Wnt signaling as a candidate pathway leading to a redirection of differentiation away from neuroepithelial cells towards neural crest. Intervention experiments, using a Wnt/beta-catenin antagonist, led to a phenotypic rescue of this disturbed differentiation. Thus, our broadly applicable model allows the analysis of transcriptome changes in complex time/perturbation matrices.

Meropenem for management of valproic acid overdose: a case report

Objectives Valproic acid (VPA) is an anticonvulsant used in several clinical scenarios. VPA has been increasingly associated with intentional or unintentional overdose. In patients presenting with severe VPA overdose, supportive care and airway protection are cornerstones of treatment, while levocarnitine is suggested in patients with hyperammonemia and hemodialysis is recommended in patients with VPA serum concentrations (SC) >1,300 mg/L and presence of cerebral edema or shock. Meropenem is a carbapenem antibiotic with a broad spectrum of activity. The pharmacological interaction between VPA and meropenem is characterized by a rapid decrease in VPA concentrations, which contraindicates concurrent use. Case presentation The following case report describes the use of meropenem to enhance the clearance of VPA in the case of severe VPA overdose. A patient with altered mental status was transported to the emergency department (ED) after VPA overdose. Meropenem was prescribed for significant elevated VPA SC. An important decline in SC was observed with short-term meropenem dosing, and an improvement in mental status occurred shortly after administration. Conclusions Carbapenem therapy has the potential to be used as last line strategy in the management of severe VPA overdose in patients where SC represent a significant risk of toxicity and clinical symptoms suggest difficulty managing the patient.

Synthesis of a novel amide derivative of valproic acid and 1,3,4-thiadiazole with antiepileptic activity

Valproates are commonly used to treat various forms of epilepsy. Problems accompanying their clinical application include drug resistance, adverse effects, acute and chronic toxicity. Safer anticonvulsants with improved efficacy can be obtained through the chemical modification of valproic acid structure. Thiadiazole-linked amide derivatives of valproates hold great promise because 1,3,4-thiadiazole can improve the drug’s bioavailability and reduce its toxicity. The aim of this work was to synthesize a novel amide derivative of valproic acid and 1,3,4-thiadiazole exerting antiepileptic activity. The chemical structure of the synthesized valproate was studied by IR, proton NMR and 13С-NMR-spectroscopy, mass spectroscopy and elemental analysis. The purity and individuality of the compound was confirmed by thin-layer and high-performance liquid chromatography. Its antiepileptic activity was assessed in the test with intraperitoneally injected 250 mg/kg isoniazid and subsequent Probit analysis. The synthesized N-(5-ethyl-1,3,4-thiadiazol-2-yl)-2-propyl pentane amide (valprazolamide) had the following characteristics. ESI+MS: m/z 256.1 [M + H]+; MRM transitions: m/z 256.1 — m/z 81.0 and m/z 130.1. The valproate exerted antiepileptic activity against isoniazid-induced seizures in mice. In the test with isoniazid, ED50 of intraperitoneally injected VPZ was 126.8 mg/kg (95% CI: 65.5–245.4). Its therapeutic index was 7.3.

Antiepileptic Overdose

Antiepileptics include various groups of drugs that have different mechanisms of actions and adverse effects. They are often also used to treat other disorders such as psychosis, chronic pain, and migraine. The most common drugs implicated in overdose include phenytoin, sodium valproate, carbamazepine, and phenobarbital. Common signs of toxicity of these drugs are central nervous system manifestations such as altered sensorium, lethargy, ataxia, and nystagmus. Some ingestions can paradoxically precipitate seizures and even status epilepticus. Sodium valproate can cause hyperammonemic encephalopathy and cerebral edema. Carbamazepine is implicated in cardiac arrhythmias and hyponatremia. Phenobarbital causes sedation, respiratory depression, and hypotension. In suspected overdose, apart from the routine laboratory tests, serum levels of the drug should be sent. Serial levels should be measured, as drug toxicity can be prolonged. Treatment of all these overdoses begins with stabilization of airway, breathing, and circulation, and endotracheal intubation being performed to protect the airway in patients with altered mental status. For decontamination, a single dose of activated charcoal should be given. Multidose of activated charcoal may be useful in phenytoin, carbamazepine, and phenobarbital overdose. Naloxone and carnitine are indicated in valproate overdose. Carbamazepine overdose can cause a widened QRS complex and arrhythmias, which can be treated with sodium bicarbonate. Forced alkaline diuresis is no longer advocated for phenobarbital poisoning. The Extracorporeal Treatments in Poisoning (EXTRIP) workgroup have formulated guidelines for extracorporeal removal of all these drugs. In most cases, hemodialysis is preferred. Other modalities include charcoal hemoperfusion (especially for carbamazepine) or continuous venovenous hemodialysis. Patients who ingest long-acting preparations should be monitored for longer periods.

Relevance of CYP2C9 Function in Valproate Therapy

BACKGROUND

Genetic polymorphisms of drug metabolizing enzymes can substantially modify the pharmacokinetics of a drug and eventually its efficacy or toxicity; however, inferring a patient's drug metabolizing capacity merely from his or her genotype can lead to false prediction. Non-genetic host factors (age, sex, disease states) and environmental factors (nutrition, comedication) can transiently alter the enzyme expression and activities resulting in genotypephenotype mismatch. Although valproic acid is a well-tolerated anticonvulsant, pediatric patients are particularly vulnerable to valproate injury that can be partly attributed to the age-related differences in metabolic pathways.

METHODS

CYP2C9 mediated oxidation of valproate, which is the minor metabolic pathway in adults, appears to become the principal route in children. Genetic and non-genetic variations in CYP2C9 activity can result in significant inter- and intra-individual differences in valproate pharmacokinetics and valproate induced adverse reactions.

RESULTS

The loss-of-function alleles, CYP2C9*2 or CYP2C9*3, display significant reduction in valproate metabolism in children; furthermore, low CYP2C9 expression in patients with CYP2C9*1/*1 genotype also leads to a decrease in valproate metabolizing capacity. Due to phenoconversion, the homozygous wild genotype, expected to be translated to CYP2C9 enzyme with normal activity, is transiently switched into poor (or extensive) metabolizer phenotype.

CONCLUSION

Novel strategy for valproate therapy adjusted to CYP2C9-status (CYP2C9 genotype and CYP2C9 expression) is strongly recommended in childhood. The early knowledge of pediatric patients' CYP2C9-status facilitates the optimization of valproate dosing which contributes to the avoidance of misdosing induced adverse reactions, such as abnormal blood levels of ammonia and alkaline phosphatase, and improves the safety of children's anticonvulsant therapy.

Valproic acid stimulates in vitro migration of the placenta-derived mesenchymal stem/stromal cell line CMSC29

Background

The placenta is an abundant source of mesenchymal stem/stromal cells (MSC), but our understanding of their functional properties remains limited. We previously created a placental-derived chorionic MSC (CMSC) cell line to overcome the difficulties associated with conducting extensive ex vivo optimization and experimental work on primary cells. The aim of this study was to characterize the migratory behavior of the CMSC29 cell line in vitro.

Methods

Stimulators of MSC migration, including two cytokines, stromal cell-derived factor-1α (SDF-1α) and hepatocyte growth factor (HGF), and a pharmacological agent, valproic acid (VPA), were tested for their ability to stimulate CMSC29 cell migration. Assessment of cell migration was performed using the xCELLigence Real-Time Cell Analyzer (RTCA).

Results

There was no significant increase in CMSC29 cell migration towards serum free medium with increasing concentration gradients of SDF-1α or HGF. In contrast, treating CMSC29 cells with VPA alone significantly increased their migration towards serum free medium.

Conclusions

Immortalized CMSC29 cells retain important properties of primary CMSC, but their migratory properties are altered. CMSC29 cells do not migrate in response to factors that reportedly stimulate primary MSC/CMSC migration. However, CMSC29 increase their migration in response to VPA treatment alone. Further studies are needed to determine the mechanism by which VPA acts alone to stimulate CMSC29 migration. Still, this study provides evidence that VPA pre-treatment may improve the benefits of cell-based therapies that employ certain MSC sub-types.

Plausibility of the zebrafish embryos/larvae as an alternative animal model for autism: A comparison study of transcriptome changes

Autism spectrum disorder (ASD) is a serious neurodevelopmental disorder characterized by impaired or abnormal social interaction and communication and by restricted and repetitive behaviour. ASD is highly prevalent in Asia, Europe, and the United States, and the frequency of ASD is growing each year. Recent epidemiological studies have indicated that ASD may be caused or triggered by exposure to chemicals in the environment, such as those in the air or water. Thus, toxicological studies are needed to examine chemicals that might be implicated. However, the experimental efficiency of existing experimental models is limited, and many models represent challenges in terms of animal welfare. Thus, alternative ASD animal models are necessary. To address this, we examined the efficacy of the zebrafish embryo/larva as an alternative model of ASD. Specifically, we exposed zebrafish to valproic acid (0, 12.5, 25, 50, or 100 μM), which is a chemical known to induce autism-like effects. We then analysed subsequent developmental, behavioural, and transcriptomic changes. We found that 100 μM and 50 μM valproic acid decreased the hatching rate and locomotor activity of zebrafish embryos/larvae. Transcriptomic analysis revealed significant alterations in a number of genes associated with autism, such as adsl, mbd5, shank3, and tsc1b. Additionally, we found changes in gene ontology that were also reported in previous studies. Our findings indicate that zebrafish embryos/larvae and humans with ASD might have common physiological pathways, indicating that this animal model may represent an alternative tool for examining the causes of and potential treatments for this illness.

Valproic acid inhibits the protective effects of stromal cells against chemotherapy in breast cancer: Insights from proteomics and systems biology

Interaction between tumor and stromal cells is beginning to be decoded as a contributor to chemotherapy resistance. Here, we aim to take a system-level approach to explore a mechanism by which stromal cells induce chemoresistance in cancer cells and subsequently identify a drug that can inhibit such interaction. Using a proteomic dataset containing quantitative data on secretome of stromal cells, we performed multivariate analyses and found that bone-marrow mesenchymal stem cells (BM-MSCs) play the most protective role against chemotherapeutics. Pathway enrichment tests showed that secreted cytokines from BM-MSCs activated 4 signaling pathways including Janus kinase-signal transducer and activator of transcription, phosphatidylinositol 3-kinase-protein kinase B, and mitogen-activated protein kinase, transforming growth factor-β in cancer cells collectively leading to nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) transcription factor activation. Based on the data from integrated Library of Integrated Network-Based Cellular Signatures (iLINCs) program, we found that among different drugs, valproic acid (VA) affected the expression of 34 genes within the identified pathways that are activated by stromal cells. Our in vitro experiments confirmed that VA inhibits NF-kB activation in cancer cells. In addition, analyzing gene expression data in patients taking oral VA showed that this drug decreased expression of antioxidant enzymes culminating in increased oxidative stress in tumor cells. These results suggest that VA confines the protective role of stromal cells by inhibiting the adaptation mechanisms toward oxidative stress which is potentiated by stromal cells. Since VA is an already prescribed drug manifesting anticancer effects, this study provides a mechanistic insight for combination of VA with chemotherapy in the clinical setting.