The effect of valproic acid on sleep structure and ethanol consumption in rats with various types of individual reactivity before and after stress exposure

The influence of valproic acid on sleep structure and alcohol motivation was studied in pretyped rats prior and following REM sleep deprivation. During EEG recording of wake-sleep cycle valporoic acid was shown to produce hypnotic action dependent on drug dosage in high active and low active animals. There was also shown that following REM sleep deprivation low active animals significantly reduced ethanol consumption under valproic acid influence. It seems likely from the results obtained that valproic acid could be used as hypnotic and antialcoholic drug.     

Valproic acid analysis in saliva and serum using selected ion monitoring (electron ionization) of the tert.-butyldimethylsilyl derivatives

A highly sensitive ion monitoring method for the determination of valproic acid in saliva and in serum has been developed based on the gas chromatographic—mass spectrometric analysis of the tert.-butyldimethylsilyl derivatives. Extraction methods are simple and the techniques for derivatization are rapid and convenient. Selected ion monitoring was carried out using electron ionization conditions and a common ion m/z 201 (M⁺ − 57) present in valproic acid and the internal standard octanoic acid. The lower limit of sensitivity that has acceptable precision for assay purposes is 0.1 mg/l based on a 200-μl sample size. The ion monitoring method (derivatized) was compared to a gas chromatographic method (underivatized) for serum valproate assays and found to be essentially identical.The assay methodology was used in a kinetic study of valproic acid in two normal subjects. Saliva levels of drug were found to give reasonably good correlations with serum total and with serum free concentrations of drug in both individuals.     

Effect of anticonvulsant drugs on plasma total cholesterol, high-density lipoprotein cholesterol, and apolipoproteins A and B in children with epilepsy

The effect of long-term anticonvulsant drug therapy with phenobarbital, phenytoin, carbamazepine, primidone, and valproic acid in epileptic children on plasma total cholesterol and high-density lipoprotein cholesterol (HDLC) was studied. Except valproic acid, all the drugs significantly increased the total cholesterol and HDLC, but the effect was more pronounced with HDLC. Among the subfractions of HDLC, almost all the increase due to drug therapy were in the HDLC-2 fraction. Treatment with antiepileptic drugs had no effect on HDLC-3. Apolipoprotein-A levels were significantly higher with drug therapy, but no effect was seen in the apolipoprotein-B levels. Plasma concentration of total cholesterol, HDLC, or its components was unaffected with valproic acid therapy.     

Zinc concentrations in mouse embryo and maternal plasma

The effect of a single teratogenic dose of the antiepileptic drug valproic acid and its nonteratogenic metabolite, 2-en-valproic acid, on zinc concentrations in mouse plasma, embryo, and decidua on d 9 of gestation was investigated. The substances were injected subcutaneously (sc) as their sodium salts. In this mouse model, valproic acid induced between 20% (400 mg/kg dose) and 60% (600 mg/kg dose) incidence of exencephaly in living fetuses; 2-en-valproic acid was not teratogenic at these dose levels. The zinc concentrations in plasma were significantly increased 1 and 2 h after administration of both substances. The embryonic zinc concentrations were increased 2 and 4 h after application of both substances. The concentrations of zinc in the decidua were not affected. The similarity of effects of valproic acid and its nonteratogenic analog on zinc concentrations in maternal plasma and embryo suggests that the teratogenicity of a single administration of valproic acid in the mouse is not owing to interference with the zinc metabolism in this species.     

Determination of valproic acid kinetics in patients during maintenance therapy using a tetradeuterated form of the drug

A method has been developed for measuring concentrations of valproic acid and, with stable isotopes, labelled forms of VPA, in the plasma of patients undergoing maintenance therapy. One tetradeutero isomer of valproic acid-di-(2,3-dideuteropropyl) acetic acid-has been synthesized for administration to patients. A [2H14]valproic acid-diheptadeuteropropyl acetic acid-was synthesized as the internal standard. After isolation from body fluids the acids were methylated with diazomethane. The McLafferty fragments of the methyl esters were used for mass spectrometric quantification. It was demonstrated that the [2H4]valproic acid used behaves kinetically like the unlabelled drug in the human body. One dose of [2H4]valproic acid was given as a pulse dose to epileptic patients and the elimination profile was measured during continuous normal treatment. The half-life of valproic acid in patients under barbiturate or carbamazepine co-medication was reduced to at least half the value found after single dose administration to healthy volunteers.     

Protective effects of valproic acid against airway hyperresponsiveness and airway remodeling in a mouse model of allergic airways disease

Airway remodeling and airway hyperresponsiveness are major aspects of asthma pathology that are not targeted optimally by existing anti-inflammatory drugs. Histone deacetylase inhibitors have a wide range of effects that may potentially abrogate aspects of remodeling. One such histone deacetylase inhibitor is valproic acid (2-propylvaleric acid). Valproic acid is used clinically as an anti-epileptic drug and is a potent inhibitor of class I histone deacetylases but also inhibits class II histone deacetylases. We used valproic acid as a molecular model of histone deacetylase inhibition in vivo in chronic allergic airways disease mice with airway remodeling and airway hyperresponsiveness. Wild-type Balb/c mice with allergic airways disease were treated with valproic acid or vehicle control. Airway inflammation was assessed by bronchoalveolar lavage fluid cell counts and examination of lung tissue sections. Remodeling was assessed by morphometric analysis of histochemically stained slides and lung function was assessed by invasive plethysmography measurement of airway resistance. Valproic acid treatment did not affect inflammation parameters; however, valproic acid treatment resulted in reduced epithelial thickness as compared to vehicle treated mice

(p < 0.01), reduced subepithelial collagen deposition (p < 0.05) and attenuated airway hyperresponsiveness (p < 0.05 and p < 0.01 for the two highest doses of methacholine, respectively). These findings show that treatment with valproic acid can reduce structural airway remodeling changes and hyperresponsiveness, providing further evidence for the potential use of histone deacetylase inhibitors for the treatment of asthma.     

Induction of GRP78 by valproic acid is dependent upon histone deacetylase inhibition

Valproic (2-propylpentanoic) acid is a commonly used drug in the treatment of bipolar disorder and epilepsy. The molecular mechanism that underlies its clinical efficacy remains controversial and is complicated by the broad range of intracellular effects of valproic acid, including its ability to inhibit histone deacetylase (HDAC) and induce protein chaperone expression. Here we show that an established HDAC inhibitor, trichostatin A, promotes ER chaperone expression in HEK293 cells. Furthermore, we use chemical derivatives of valproic acid to show that the ability to promote GRP78 levels directly correlates with the induction of histone H4 hyperacetylation. These results suggest that exposure to valproic acid enhances chaperone expression by a mechanism that involves histone hyperacetylation.     

Pattern- and age-dependency of the antiepileptic effects induced by valproic acid in the rat hippocampus.

The effects induced by the antiepileptic drug valproic acid were studied in the CA3 subfield of in vitro hippocampal slices obtained from young (16- to 27-day-old) and adult (over 60-day-old) rats. Spontaneous epileptiform discharges were induced by the addition of the convulsant 4-aminopyridine to the medium. Valproic acid (0.5 mM) selectively blocked the ictal epileptiform discharges in slices obtained from young rats. Interictal epileptiform discharges disappeared during perfusion with higher doses of valproic acid (2 mM). This blockade of interictal epileptiform activity was not observed when valproic acid (0.5-5 mM) was tested in hippocampal slices from adult rats. Thus, in the hippocampus of young rats, 4-aminopyridine-induced ictal activity is more sensitive to valproic acid than are interictal discharges. Moreover, valproic acid is effective in controlling interictal discharges in the young, but not in the adult rat hippocampus.     

Protective effects of valproic acid against airway hyperresponsiveness and airway remodeling in a mouse model of allergic airways disease

Airway remodeling and airway hyperresponsiveness are major aspects of asthma pathology that are not targeted optimally by existing anti-inflammatory drugs. Histone deacetylase inhibitors have a wide range of effects that may potentially abrogate aspects of remodeling. One such histone deacetylase inhibitor is valproic acid (2-propylvaleric acid). Valproic acid is used clinically as an anti-epileptic drug and is a potent inhibitor of class I histone deacetylases but also inhibits class II histone deacetylases. We used valproic acid as a molecular model of histone deacetylase inhibition in vivo in chronic allergic airways disease mice with airway remodeling and airway hyperresponsiveness. Wild-type Balb/c mice with allergic airways disease were treated with valproic acid or vehicle control. Airway inflammation was assessed by bronchoalveolar lavage fluid cell counts and examination of lung tissue sections. Remodeling was assessed by morphometric analysis of histochemically stained slides and lung function was assessed by invasive plethysmography measurement of airway resistance. Valproic acid treatment did not affect inflammation parameters; however, valproic acid treatment resulted in reduced epithelial thickness as compared to vehicle treated mice (p < 0.01), reduced subepithelial collagen deposition (p < 0.05) and attenuated airway hyperresponsiveness (p < 0.05 and p < 0.01 for the two highest doses of methacholine, respectively). These findings show that treatment with valproic acid can reduce structural airway remodeling changes and hyperresponsiveness, providing further evidence for the potential use of histone deacetylase inhibitors for the treatment of asthma.     

Valproic Acid and Fatalities in Children: A Review of Individual Case Safety Reports in VigiBase

Introduction

Valproic acid is an effective first line drug for the treatment of epilepsy. Hepatotoxicity is a rare and potentially fatal adverse reaction for this medicine.

Objective

Firstly to characterise valproic acid reports on children with fatal outcome and secondly to determine reporting over time of hepatotoxicity with fatal outcome.

Methods

Individual case safety reports (ICSRs) for children ≤17 years with valproic acid and fatal outcome were retrieved from the WHO Global ICSR database, VigiBase, in June 2013. Reports were classified into hepatotoxic reactions or other reactions. Shrinkage observed-to-expected ratios were used to explore the relative reporting trend over time and for patient age. The frequency of polytherapy, i.e. reports with more than one antiepileptic medicine, was investigated.

Results

There have been 268 ICSRs with valproic acid and fatal outcome in children, reported from 25 countries since 1977. A total of 156 fatalities were reported with hepatotoxicity, which has been continuously and disproportionally reported over time. There were 31 fatalities with pancreatitis. Other frequently reported events were coma/encephalopathy, seizures, respiratory disorders and coagulopathy. Hepatotoxicity was disproportionally and most commonly reported in children aged 6 years and under (104/156 reports) but affected children of all ages. Polytherapy was significantly more frequently reported for valproic acid with fatal outcome (58%) compared with non-fatal outcome (34%).

Conclusion

Hepatotoxicity remains a considerable problem. The risk appears to be greatest in young children (6 years and below) but can occur at any age. Polytherapy is commonly reported and seems to be a risk factor for hepatotoxicity, pancreatitis and other serious adverse drug reactions with valproic acid.     

Wfs1 mutation makes mice sensitive to insulin-like effect of acute valproic acid and resistant to streptozocin

Valproic acid (VLP) is a widely used anticonvulsant and mood-stabilizing drug that relieves the endoplasmic reticulum (ER) stress response, a pathogenetic process related to diabetes. The aim of the present study was to evaluate whether acute valproic acid is able to interfere with glucose intolerance in two different diabetes models: The first model was a Wfs1 mutant mouse with an elevated ER stress response and the second model a streptozocin-induced diabetic mouse. VLP (300 mg/kg, i.p.) was administered to Wfs1 knockout (KO) mice and glucose tolerance test was performed 15 min later. VLP did not have an effect on the course of the glucose tolerance test in wild-type mice, while it did normalize the glucose intolerance in Wfs1 knockout mice. Acute valproic acid also lowered the blood glucose levels in streptozocin-treated mice and potentiated the effect of insulin in these mice. Thus, acute valproic acid is effective in lowering blood glucose levels possibly by potentiating insulin action in both Wfs1 KO mice and in streptozocin-induced type 1 diabetic mice.     

Anemia secondary to valproic acid therapy in a 13- year-old boy: a case report

ABSTRACT: INTRODUCTION: Valproic acid is a commonly used anti-epileptic drug. Hematological toxicities are among theoccasionally observed adverse effects of this medication. CASE PRESENTATION: We present the case of a 13-year-old Caucasian boy who demonstrated mild anemia 12months after the introduction of valproic acid therapy. A bone marrow biopsy revealedmaturation arrest of proerythroblasts. CONCLUSION: Prompt diagnosis and valproic acid discontinuation resulted in the patient's recovery.     

Simultaneous treatment with camptothecin and valproic acid suppresses induction of Bcl-XL and promotes apoptosis of MCF-7 breast cancer cells

Camptothecin derivatives have been widely used for chemotherapy in patients with various cancers, but intrinsic and acquired drug resistance is major drawback to be overcome. In the present study, we demonstrated that simultaneous treatment with camptothecin and valproic acid induced apoptosis of MCF-7 cells, whereas neither agent alone could efficiently induce apoptosis. This induction of apoptosis was associated with loss of the mitochondrial membrane potential and was caspase dependent. Further investigation showed that concurrent treatment modulated the expression of pro-apoptotic and anti-apoptotic genes. Bcl-X_L expression was induced in MCF-7 cells treated with camptothecin alone, but not in cells treated simultaneously with camptothecin and valproic acid. Ectopic overexpression of Bcl-X_L in MCF-7 cells completely suppressed the induction of apoptosis, even with simultaneous treatment. On the other hand, efficient induction of apoptosis was achieved by treatment with camptothecin and Bcl-X_L inactivation (using siRNA or BH3 mimetic). The cytotoxic effect of camptothecin combined with valproic acid was more than additive for MCF-7 cells. Taken together, our results suggest that simultaneous administration of camptothecin and valproic acid might be useful for anticancer therapy.     

Direct interaction between the catalytic subunit of Protein Phosphatase 1 and pRb

Background

Among the epigenetic alterations occurring in cancer, DNA hypermethylation and histone hypoacetylation are the focus of intense research because their pharmacological inhibition has shown to produce antineoplastic activity in a variety of experimental models. The objective of this study was to evaluate the combined antineoplastic effect of the DNA methylation inhibitor hydralazine and the histone deacetylase inhibitor valproic acid in a panel of cancer cell lines.

Results

Hydralazine showed no growth inhibitory effect on cervical, colon, breast, sarcoma, glioma, and head & neck cancer cell lines when used alone. On the contrary, valproic acid showed a strong growth inhibitory effect that is potentiated by hydralazine in some cell lines. Individually, hydralazine and valproic acid displayed distinctive effects upon global gene over-expression but the number of genes over-expressed increased when cells were treated with the combination. Treatment of HeLa cells with hydralazine and valproic acid lead to an increase in the cytotoxicity of gemcitabine, cisplatin and adriamycin. A higher antitumor effect of adriamycin was observed in mice xenografted with human fibrosarcoma cells when the animals were co-treated with hydralazine and valproic acid.

Conclusion

Hydralazine and valproic acid, two widely used drugs for cardiovascular and neurological conditions respectively have promising antineoplastic effects when used concurrently and may increase the antitumor efficacy of current cytotoxic agents.     

Marked accumulation of valproic acid in embryonic neuroepithelium of the mouse during early organogenesis

Valproic acid, an antiepileptic drug, causes neural tube defects in mice and man. 14C-labeled valproic acid (sodium-salt) was administered to pregnant mice on days 8 and 9 of gestation (period of high sensitivity in regard to formation of neural tube defects in this species). Two dose levels of valproic acid (1 and 400 mg/kg) were used; in each case the total radioactivity administered was the same: 400 microCi/kg or 14.7 MBq/kg. Autoradiography combined with computerized densitometry revealed that in low-dose animals most of the radioactivity was confined to maternal liver and kidney, while at high doses more activity was observed in soft tissues and fluids, including amniotic fluid. In the embryo, the neuroepithelium showed the highest concentration, irrespective of dose and survival interval (30 min, 3 h, and 6 h). Upon administration of the high dose, up to five times more radioactivity (approximately 2,000 times more valproic acid) was recovered in embryonic tissues than after the low dose. It is concluded that high doses of VPA saturate the capacities of metabolism, excretion, and protein binding in the maternal organism, resulting in a higher proportion of the dose reaching the embryo, allowing more of the drug to be accumulated by the target organ, the neuroepithelium.     

The inhibition by valproic acid of the mitochondrial oxidation of monocarboxylic and omega-hydroxymonocarboxylic acids: possible implications for the metabolism of gamma-aminobutyric acid

The interactions of 1-5 mM valproic acid with the hepatic fatty acid oxidation are here described. Valproic acid was not substrate for hepatic peroxisomal fatty acid oxidation. Its activation outside the mitochondrial matrix compartment was poor when compared to that of octanoic acid, a fatty acid containing the same number of carbones. Valproic acid did not inhibit the fatty acyl-CoA oxidase nor the cyanide-insensitive acyl-CoA oxidation. Valproic acid inhibited the mitochondrial oxidations of both long-chain monocarboxylyl-CoAs and omega-hydroxymonocarboxylyl-CoAs. Valproic acid prevented the oxidation by coupled mitochondria of decanoic and 10-hydroxydecanoic acids. Both butyric and 4-hydroxybutyric acids were oxidized by coupled mitochondria. These activities were abolished by preincubating the enzyme source with valproic acid. Administration to rats of 0.5% (w/w)- or 1% (w/w)-valproate containing diets were efficient in producing increased liver peroxisomal population and beta-oxidation. Preliminary investigations on the effects of valproic acid on mitochondrial fatty acid oxidation as a function of the animal used for the experiments pointed out an association of the protection of the mitochondrial process against the toxicity of the drug with enhanced carnitine acyltransferase and acyl-CoA hydrolase activities.     

Plasma vitamin values and antiepileptic therapy: case reports of pregnancy outcomes affected by a neural tube defect

BACKGROUND: Folic acid supplementation reduces the occurrence of neural tube defects (NTDs); however, it is not clear whether it protects against teratogenic effects of antiepileptic drugs. METHODS: We report the cases of four pregnant women receiving valproic acid therapy, who all had NTD-affected offspring, despite periconceptional 5 mg/day of folic acid supplementation (cases), and investigated homocysteine metabolism, linked with folate metabolism. Their plasma homocysteine, folates, and vitamin B6 and B12 results were compared with values of two other women, who were also receiving valproic acid and folic acid complement, but who had normal pregnancies (valproic acid controls), and values of 40 pregnant women who had normal pregnancies and were not receiving any therapy (controls without therapy). Because of the possible existence of a genetic susceptibility, polymorphisms in homocysteine metabolism were sought. RESULTS: Two cases showed a decreased phosphopyridoxal level, compared with levels in the controls not receiving therapy. The genotype TT (C677T) is an NTD genetic susceptibility, but it was observed in only one valproic acid control. Various polymorphisms were observed in the cases, but were also common in the controls. Several studies have reported that valproic acid therapy lowers vitamin B6 levels. Our case with the greatest decrease in plasma phosphopyridoxal, who was taking periconceptional folic acid plus pyridoxine therapy, had a normal second pregnancy outcome. CONCLUSIONS: In addition to folates, other vitamins, such as vitamin B6, may have played a role in NTDs in our patients taking an antiepileptic drug.