Toxicity of Antiepileptic Drugs to Mitochondria

Mitochondrial encephalopathies and myopathies: Our tertiary center's experience

Mitochondrial diseases have a heterogeneous phenotype and can result from mutations in the mitochondrial or nuclear genomes, constituting a diagnostically and therapeutically challenging group of disorders. We report our center's experience with mitochondrial encephalopathies and myopathies with a cohort of 50 genetically and phenotypically diverse patients followed in the Neurology clinic over the last ten years. Seventeen patients had mitochondrial DNA mutations, presented over a wide range of ages with seizures, feeding difficulties, extraocular movements abnormalities, and had high rates of stroke-like episodes and regression. Twenty-seven patients had nuclear DNA mutations, presented early in life with feeding difficulty, failure-to-thrive, and seizures, and had high proportions of developmental delay, wheelchair dependence, spine abnormalities and dystonia. In six patients, a mutation could not be identified, but they were included for having mitochondrial disease confirmed by histopathology, enzyme analysis and clinical features. These patients had similar characteristics to patients with nuclear DNA mutations, suggesting missed underlying mutations in the nuclear genome. Management was variable among patients, but outcomes were universally poor with severe disability in all cases. Therapeutic entryways through elucidation of disease pathways and remaining unknown genes are acutely needed.

Valproic Acid in Pregnancy Revisited: Neurobehavioral, Biochemical and Molecular Changes Affecting the Embryo and Fetus in Humans and in Animals: A Narrative Review

Valproic acid (VPA) is a very effective anticonvulsant and mood stabilizer with relatively few side effects. Being an epigenetic modulator, it undergoes clinical trials for the treatment of advanced prostatic and breast cancer. However, in pregnancy, it seems to be the most teratogenic antiepileptic drug. Among the proven effects are congenital malformations in about 10%. The more common congenital malformations are neural tube defects, cardiac anomalies, urogenital malformations including hypospadias, skeletal malformations and orofacial clefts. These effects are dose related; daily doses below 600 mg have a limited teratogenic potential. VPA, when added to other anti-seizure medications, increases the malformations rate. It induces malformations even when taken for indications other than epilepsy, adding to the data that epilepsy is not responsible for the teratogenic effects. VPA increases the rate of neurodevelopmental problems causing reduced cognitive abilities and language impairment. It also increases the prevalence of specific neurodevelopmental syndromes like autism (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). High doses of folic acid administered prior to and during pregnancy might alleviate some of the teratogenic effect of VPA and other AEDs. Several teratogenic mechanisms are proposed for VPA, but the most important mechanisms seem to be its effects on the metabolism of folate, SAMe and histones, thus affecting DNA methylation. VPA crosses the human placenta and was found at higher concentrations in fetal blood. Its concentrations in milk are low, therefore nursing is permitted. Animal studies generally recapitulate human data.

Mitochondrial Effects of Common Cardiovascular Medications: The Good, the Bad and the Mixed

Mitochondria are central organelles in the homeostasis of the cardiovascular system via the integration of several physiological processes, such as ATP generation via oxidative phosphorylation, synthesis/exchange of metabolites, calcium sequestration, reactive oxygen species (ROS) production/buffering and control of cellular survival/death. Mitochondrial impairment has been widely recognized as a central pathomechanism of almost all cardiovascular diseases, rendering these organelles important therapeutic targets. Mitochondrial dysfunction has been reported to occur in the setting of drug-induced toxicity in several tissues and organs, including the heart. Members of the drug classes currently used in the therapeutics of cardiovascular pathologies have been reported to both support and undermine mitochondrial function. For the latter case, mitochondrial toxicity is the consequence of drug interference (direct or off-target effects) with mitochondrial respiration/energy conversion, DNA replication, ROS production and detoxification, cell death signaling and mitochondrial dynamics. The present narrative review aims to summarize the beneficial and deleterious mitochondrial effects of common cardiovascular medications as described in various experimental models and identify those for which evidence for both types of effects is available in the literature.

Case report: Monoclonal CGRP-antibody treatment in a migraine patient with a mutation in the mitochondrial single-strand binding protein (SSBP1)

Background

There is a growing body of mitochondrial disorders that are associated with headaches, albeit only one of them is currently listed in the latest International Classification of Headache Disorders, 3rd edition (ICHD-3). Headache frequency and headache presentation can vary widely in this respective patient group. Acute and preventive migraine treatment can be quite challenging—the use of several established medications is often limited due to their side effects in the setting of mitochondrial dysfunction and multi-organ disease.

Case presentation

Along with a review of the literature on treatment options in patients with mitochondrial disorders and migraine headaches, we present the case of a 23-year-old male with a homozygous mutation in the mitochondrial single-strand binding protein (SSBP1) with chronic migraine with aura. After failing several standard of care prophylactics due to either side effects or inefficacy, he was successfully treated with a monoclonal anti-CGRP-antibody as a preventive migraine treatment. The monoclonal antibody was well tolerated and showed adequate efficacy with a sustained > 50% reduction in monthly headache days after 3 years of treatment.

Conclusion

Migraine is often challenging to treat in patients with mitochondriopathy due to therapy-limiting comorbidities. Monoclonal CGRP-antibodies might be a safe treatment option in the prevention of migraine headaches in patients with a mitochondrial disorder.

Late onset AMACR deficiency with metabolic stroke-like episodes and seizures

Alpha-methylacyl-CoA racemase (AMACR) deficiency is a rare peroxisomal disorder causing pristanic acid accumulation. Only 16 cases have been described so far. A female in her seventh decade presented with episodes of dysphasia, headache and sensory disturbance inconsistent with migraine, epilepsy or transient ischaemic attack. An MRI demonstrated unusual changes in the pons, red nuclei, thalami and white matter. Mitochondrial disease was suspected but detailed testing was negative. After eight years of symptoms, she developed a febrile encephalopathy with hemispheric dysfunction, focal convulsive seizures and coma. Her condition stabilised after one month. Lacosamide was continued for seizure prevention. The diagnosis remained elusive until whole genome sequencing revealed AMACR deficiency. Pristanic acid levels were highly elevated and dietary modification was recommended. Genetic peroxisomal disorders can present in older age; our patient is the oldest in the AMACR deficiency literature. Novel features in our case include central apnoea, dystonia and rapid eye movement behaviour disorder.

Cell wall thickenings and tylosoid: developmental morphology reveals novelties for secretory canals in Protium ovatum (Burseraceae)

We investigated the structure, histochemistry, and ultrastructure of the secretory canals in the vegetative axis of Protium ovatum from a developmental perspective. Samples of roots, stems, and leaves were analyzed using light and transmission electron microscopy. Secretory canals composed of a uniseriate epithelium and a wide lumen occurred in the phloem of all analyzed organs. Schizogenesis and lysigenesis were merging processes involved in the origin, growth, ramification, and fusion of the secretory canals, forming an anastomosed secretory net. Essential oils, polysaccharides, and proteins were detected in the epithelial cells, as well as plastids with poorly developed thylakoids, dictyosomes, rough endoplasmic reticulum, polysomes, and oil drops, showing the mixed nature of the secretion. Epithelial cells exhibited pectin-cellulosic thickenings in the anticlinal and radial walls. These thickenings may act in directing the secretion flux toward the lumen, protecting the neighboring tissues from the toxicity of secreted metabolites. Structural irregularities observed in the mitochondria cristae in epithelial cells may be associated with processes induced by toxic substances. Epithelial cells protruded into the lumen and became lignified in the outer portion of the secondary phloem, obliterating the non-functional secretory canals. We propose that this phenomenon presents a physiological significance similar to that of tylose, preserving the secretion flow inside the active portions of the secretory system. To our knowledge, epithelial cells with wall thickenings, mitochondria with structural abnormalities, and obliteration of non-functional canals are features reported for the first time for Burseraceae. These features have important functional significance for Burseraceae secretory system and contribute to a deeper knowledge of P. ovatum, a medically and economically important plant.

Seizure Semiology, EEG, and Imaging Findings in Epilepsy Secondary to Mitochondrial Disease

Background: Identification of an underlying mitochondrial disorder can be challenging due to the significant phenotypic variability between and within specific disorders. Epilepsy can be a presenting symptom with several mitochondrial disorders. In this study, we evaluated clinical, electrophysiologic, and imaging features in patients with epilepsy and mitochondrial disorders to identify common features, which could aid in earlier identification of a mitochondrial etiology. Methods: This is a retrospective case series from January 2011 to December 2019 at a tertiary referral center of patients with epilepsy and a genetically confirmed diagnosis of a mitochondrial disorder. A total of 164 patients were reviewed with 20 patients fulfilling inclusion criteria. Results: A total of 20 patients (14 females, 6 males) aged 0.5-61 years with epilepsy and genetically confirmed mitochondrial disorders were identified. Status epilepticus occurred in 15 patients, with focal status epilepticus in 13 patients, including 9 patients with visual features. Abnormalities over the posterior cerebral regions were seen in 66% of ictal recordings and 44% of imaging studies. All the patients were on nutraceutical supplementation with no significant change in disease progression seen. At last follow-up, eight patients were deceased and the remainder had moderate-to-severe disability. Discussion: In this series of patients with epilepsy and mitochondrial disorders, we found increased propensity for seizures arising from the posterior cerebral regions. Over time, electroencephalogram (EEG) and imaging abnormalities increasingly occurred over the posterior cerebral regions. Focal seizures and focal status epilepticus with visual symptoms were common. Additional study is needed on nutraceutical supplementation in mitochondrial disorders.

Knowledge about the characteristics of stroke-like lesions is expandable

Stroke-like episodes (SLEs) are a common phenotypic feature of various syndromic and non-syndromic mitochondrial disorders (MIDs), particularly of mitochondrial encephalopathy, lactic acidosis, and stroke-like episode syndrome (MELAS). The morphological equivalent of a SLE is the stroke-like lesion (SLE), a dynamic lesion, which initially expands to regress after weeks or months. SLLs present with typical morphological and structural abnormalities on multimodal magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and FDG-PET. It is crucial to clearly delineate SLLs from ischemic stroke, as treatment and outcome vary significantly between the two.

Epilepsy in Mitochondrial Diseases-Current State of Knowledge on Aetiology and Treatment

Mitochondrial diseases are a heterogeneous group of diseases resulting from energy deficit and reduced adenosine triphosphate (ATP) production due to impaired oxidative phosphorylation. The manifestation of mitochondrial disease is usually multi-organ. Epilepsy is one of the most common manifestations of diseases resulting from mitochondrial dysfunction, especially in children. The onset of epilepsy is associated with poor prognosis, while its treatment is very challenging, which further adversely affects the course of these disorders. Fortunately, our knowledge of mitochondrial diseases is still growing, which gives hope for patients to improve their condition in the future. The paper presents the pathophysiology, clinical picture and treatment options for epilepsy in patients with mitochondrial disease.

Epilepsy Associated With Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes

Objectives: The present study explored the clinical characteristics and prognostic factors of epilepsy in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS).

Methods: Thirty-four MELAS patients were included in the present study. They were diagnosed by clinical characteristics, genetic testing, muscle biopsy, and retrospective analysis of other clinical data. The patients were divided into three groups according to the effects of treatment after at least 2 years of follow-up.

Results: Epilepsy was more common in male MELAS patients than in females (20/14). The age of onset ranged from 0.5 to 57 years, with an average of 22.6 years. Patients with epilepsy and MELAS had various forms of seizures. Focal seizures were the most common type affecting 58.82% of patients, and some patients had multiple types of seizures. The abnormal EEG waves were mainly concentrated in the occipital (69.57%), frontal (65.22%) and temporal lobes (47.83%). Overall, the prognosis of patients with epilepsy and MELAS was poor. Poor prognosis was associated with brain atrophy (P = 0.026), status epilepticus (P < 0.001), and use of anti-seizure medications with high mitochondrial toxicity (P = 0.015).

Interpretation: Avoiding the application of anti-seizure medications with high mitochondrial toxicity, controlling seizures more actively and effectively, and delaying the occurrence and progression of brain atrophy as much as possible are particularly important to improve the prognosis of patients with MELAS and epilepsy.

Clinical Therapeutic Management of Human Mitochondrial Disorders

Despite recent advances in the elucidation of etiology and pathogenesis of mitochondrial disorders, their therapeutic management remains challenging. This review focuses on currently available therapeutic options for human mitochondrial disorders. Current treatment of mitochondrial disorders relies on symptomatic, multidisciplinary therapies of various manifestations in organs such as the brain, muscle, nerves, eyes, ears, endocrine organs, heart, intestines, kidneys, lungs, bones, bone marrow, cartilage, immune system, and skin. If respiratory chain functions are primarily or secondarily impaired, antioxidants or cofactors should be additionally given one by one. All patients with mitochondrial disorders should be offered an individually tailored diet and physical training program. Irrespective of the pathogenesis, all patients with mitochondrial disorders should avoid exposure to mitochondrion-toxic agents and environments. Specific treatment can be offered for stroke-like episodes, mitochondrial epilepsy, mitochondrial neurogastrointestinal encephalopathy, Leber hereditary optic neuropathy, thiamine-responsive Leigh syndrome, primary coenzyme Q deficiency, primary carnitine deficiency, Friedreich ataxia, ethylmalonic encephalopathy, acyl-CoA dehydrogenase deficiency, pyruvate dehydrogenase deficiency, and hereditary vitamin E deficiency. Preventing the transmission of mitochondrial DNA-related mitochondrial disorders can be achieved by mitochondrion replacement therapy (spindle transfer, pronuclear transfer). In conclusion, specific and nonspecific therapies for human mitochondrial disorders are available, and beneficial effects have been anecdotally reported. However, double-blind, placebo-controlled studies to confirm effectiveness are lacking for the majority of the measures applied to mitochondrial disorders. Transmission of certain mitochondrial disorders can be prevented by mitochondrion replacement therapy. A multidisciplinary approach is required to meet the therapeutic challenges of patients with mitochondrial disorders.

Selenium and L-carnitine protects from valproic acid-Induced oxidative stress and mitochondrial damages in rat cortical neurons

Oxidative stress and mitochondrial dysfunction have been associated with valproic acid (VPA) induced neurotoxicity. Mitochondria are vulnerable to oxidative damage and are also a major source of superoxide free radicals. Therefore, the need for mitochondrial protective and antioxidant agents for reducing valporic acid toxicity in central nerve system (CNS) is essential. In the present study, we investigated the potential beneficial effects of sodium selenite (SS) and L-carnitine (LC) against valproic acid -induced oxidative stress and mitochondrial dysfunction in isolated rat cortical neurons. Valproic acid (50, 100 and 200 µM) treatment caused a significant decrease in cellular viability, which was accompanied by increases in reactive oxygen species (ROS) generation, GSSG and GSH content, lipid peroxidation and lysosomal and mitochondrial damages. Sodium selenite (1 µM) and L-carnitine (1 mM) pretreatment attenuated valproic acid-induced decrease in cell viability. In addition, sodium selenite (1 µM) and L-carnitine (1 mM) pretreatment significantly protected against valproic acid-induced raise in oxidative stress, mitochondrial and lysosomal dysfunction, lipid peroxidation levels and depletion of GSH content. Our results in the current study provided insights into the protective mechanism by L-carnitine and sodium selenite, which is liked, to neuronal ROS generation and mitochondrial and lysosomal damages.

Chronic pain is common in mitochondrial disease

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Chronic pain is common in patients with mitochondrial disease.

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Pain due to mitochondrial disease is primarily of neuropathic nature.

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Distribution, intensity and type of pain are genetically determined.

In the absence of cure, the main objectives in the management of patients with mitochondrial disease are symptom control and prevention of complications. While pain is a complicating symptom in many chronic diseases and is known to have a clear impact on quality of life, its prevalence and severity in people with mitochondrial disease is unknown. We conducted a survey of pain symptoms in patients with genetically confirmed mitochondrial disease from two UK mitochondrial disease specialist centres. The majority (66.7%) of patients had chronic pain which was primarily of neuropathic nature. Presence of pain did not significantly impact overall quality of life. The m.3243A>G MTTL1 mutation was associated with higher pain severity and increased the likelihood of neuropathic pain compared to other causative nuclear and mitochondrial gene mutations. Although previously not considered a core symptom in people with mitochondrial disease, pain is a common clinical manifestation, frequently of neuropathic nature, and influenced by genotype. Therefore, pain-related symptoms should be carefully characterised and actively managed in this patient population.

Metabolic stroke or stroke-like lesion: Peculiarities of a phenomenon

OBJECTIVES

One of the most frequent cerebral lesions in mitochondrial disorders(MIDs) on imaging is the stroke-like lesion(SLL) clinically manifesting as stroke-like episode (SLE, metabolic stroke). This review aims at discussing recent advances concerning the presentation, diagnosis, and treatment of SLLs.

METHODS

Systematic literature review using appropriate search terms.

RESULTS

SLLs are the hallmark of MELAS but occasionally occur in other MIDs. SLLs are best identified on multimodal, cerebral MRI. SLLs may present as uni-/multilocular, symmetric/asymmetric, cortical/subcortical, supra-/infratentorial condition, initially resembling a cytotoxic edema and later a vasogenic edema, or a variable mix between them. SLLs run through an acute and a chronic stage. The acute stage is characterised by a progressively expanding lesion over days, weeks, or months, showing up as increasing hyperintensity on T2/FLAIR, DWI, and PWI and by hyperperfusion, that does not conform to a vascular territory. ADC maps are initially hypointens to become hyperintens during the course. More rarely, a variable mixture of hyper- and hypointensities may be found. The chronic stage is characterised by hypoperfusion, gadolinium enhancement, and regression of hyperintensities to various endpoints. SLLs originate from an initial cortical lesion due to focal metabolic breakdown, which either remains stable or expands within the cortex or to subcortical areas. Some SLLs show spontaneous reversibility (fleeing cortical lesions) suggesting that neuronal/glial damage does not reach the threshold of irreversible cell death.

CONCLUSIONS

SLLs are a unique feature of various MIDs in particular MELAS. SLLs are dynamic and change their appearance over time. SLLs are accessible to treatment.

Therapeutic management of stroke-like episodes varies from that of encephalitis

INTRODUCTION

Stroke-like episodes (SLEs) are typical cerebral manifestations of certain mitochondrial disorders (MIDs). They are characterised by a vasogenic edema in a non-vascular distribution. PATIENTS CONCERNS:: none DIAGNOSIS:: SLEs show up on cerebral MRI as stroke-like lesions (SLLs), characterised by vasogenic edema in a non-vascular distribution. SLLs expand in the acute stage and regress during the chronic stage. They show hyperperfusion in the acute stage and hypoperfusion in the chronic stage.

INTERVENTIONS

SLLs respond favorably to antiseizure drugs, to No-precursors, steroids, the ketogenic diet, and antioxidants.

OUTCOME

SLLs end up as normal tissue, white matter lesion, grey matter lesion, cyst, laminar cortical necrosis, or the toenail sign.

CONCLUSIONS

SLLs are a frequent manifestation of MIDs. They undergo dynamic changes in the acute and chronic stage. They need to be differentiated from ischemic stroke as they are differentially treated.

Stroke-like episodes in OPA1 carriers require comprehensive work-up and therapeutic considerations

This is a letter to the Editor concerning the recently published article by Zerem et al. The paper described a 12yo female with multisystem mitochondrial disorder (MID) due to the compound heterozygous variants c.1963_1964dupAT and p.Ile382Met in OPA1 manifesting phenotypically with congenital nystagmus, developmental delay, visual impairment, gait ataxia, epilepsy, a stroke-like episode (SLE) with encephalopathy and vomiting, and hearing impairment. This interesting case could be more meaningful by providing more information about the treatment of the SLE/stroke-like lesion (SLL), about the morphological characteristics of the SLL on MRI, and the results of prospective investigations for subclinical involvement of organs so far clinically unaffected.

Cluster headache as a manifestation of a stroke-like episode in a carrier of the MT-ND3 variant m.10158T>C

In a recent article Fu et al reported about a 52 years old female with a mitochondrial disorder due to the variant m.10158T>C in the mtDNA located gene MT-ND3. The study has a number of shortcomings. The study would particularly profit from providing more data about multisystem disease, from providing the current medication, the cerebro-spinal fluid findings, the detailed phenotypic presentation, and the genotype of first-degree relatives. Since the index patient had experienced recurrent seizures it is crucial to know the current and previous anti-seizure medication as it may strongly determine the outcome. Some of them are mitochondrion-toxic and particularly valproic acid may exhibit fatal side effects. The outcome may also depend on the degree of multisystem involvement why it is crucial to prospectively investigate the patient for subclinical involvement of organs not obviously affected. Additionally, the outcome of the stroke-like lesions on imaging would be interesting to see. Stroke-like lesions may completely disappear or may end up as white matter lesion, laminar cortical necrosis, focal atrophy, cyst, or as the so-called toenail sign. There is also a need of discussing more profoundly the imaging findings and their diagnostic significance and to investigate first degree relatives of the index patient clinically and genetically. Though highly interesting, the presentation of this case of a mitochondrial disorder lacks clinical and genetic data of the patient and his relatives. Outcome parameters, such as severity of disease, degree of progression, drugs, pathogenicity of the mutation, and multisystem involvement require a profound discussion.

Defined neuronal populations drive fatal phenotype in a mouse model of Leigh syndrome

Mitochondrial deficits in energy production cause untreatable and fatal pathologies known as mitochondrial disease (MD). Central nervous system affectation is critical in Leigh Syndrome (LS), a common MD presentation, leading to motor and respiratory deficits, seizures and premature death. However, only specific neuronal populations are affected. Furthermore, their molecular identity and their contribution to the disease remains unknown. Here, using a mouse model of LS lacking the mitochondrial complex I subunit Ndufs4, we dissect the critical role of genetically-defined neuronal populations in LS progression. Ndufs4 inactivation in Vglut2-expressing glutamatergic neurons leads to decreased neuronal firing, brainstem inflammation, motor and respiratory deficits, and early death. In contrast, Ndufs4 deletion in GABAergic neurons causes basal ganglia inflammation without motor or respiratory involvement, but accompanied by hypothermia and severe epileptic seizures preceding death. These results provide novel insight in the cell type-specific contribution to the pathology, dissecting the underlying cellular mechanisms of MD.

Severe infantile epileptic encephalopathy associated with D-glyceric aciduria: report of a novel case and review

D-glycerate 2 kinase (DGK) is an enzyme that mediates the conversion of D-glycerate, an intermediate metabolite of serine and fructose metabolism, to 2-phosphoglycerate. Deficiency of DGK leads to accumulation of D-glycerate in various tissues and its massive excretion in urine. D-glyceric aciduria (DGA) is an autosomal recessive metabolic disorder caused by mutations in the GLYCTK gene. The clinical spectrum of DGA is highly variable, ranging from severe progressive infantile encephalopathy to a practically asymptomatic condition. We describe a male patient from a consanguineous Arab family with infantile onset of DGA, characterized by profound psychomotor retardation, progressive microcephaly, intractable seizures, cortical blindness and deafness. Consecutive brain MR imaging showed an evolving brain atrophy, thinning of the corpus callosum and diffuse abnormal white matter signals. Whole exome sequencing identified the homozygous missense variant in the GLYCTK gene [c.455 T > C, NM_145262.3], which affected a highly conserved leucine residue located at a domain of yet unknown function of the enzyme [p.Leu152Pro, NP_660305]. In silico analysis of the variant supported its pathogenicity. A review of the 15 previously reported patients, together with the current one, confirms a clear association between DGA and severe neurological impairment. Yet, future studies of additional patients with DGA are required to better understand the clinical phenotype and pathogenesis.

Effects of Valproate Monotherapy on the Oxidant-Antioxidant Status in Mexican Epileptic Children: A Longitudinal Study

Epilepsy is a neurological disorder that can produce brain injury and neuronal death. Several factors such as oxidative stress have been implicated in epileptogenesis. Valproic acid (VPA) is a widely used drug for the treatment of epilepsy, but the mechanisms underlying these benefits are complex and still not fully understood. The objective of this study was to evaluate, for the first time, the effects of VPA on the oxidant-antioxidant status in Mexican epileptic children before and after 6 or 12 months of treatment with VPA by determining the activities of several plasmatic antioxidant enzymes (glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT)) and oxidant marker (malondialdehyde (MDA), hydrogen peroxide (H2O2), 8-hydroxy-2-deoxyguanosine (8-OHdG), and 3-nitrotyrosine (3-NT) levels) profiles. The possible relationships between these markers and some clinicopathological factors were also evaluated. Plasma samples were obtained from the peripheral blood of 16 healthy children and 32 patients diagnosed with epilepsy, and antioxidant/oxidant markers were measured spectrometrically. Significant decreases in all antioxidant enzyme activities, with the exception of GPx, and increases in all oxidant markers in epileptic subjects versus healthy children were observed. Interestingly, all these effects reverted after VPA monotherapy, although the results were different depending on the treatment period (6 or 12 months). These changes were contingent upon brain imaging findings, type of epilepsy, etiology of epilepsy, and the efficacy of 6 months of VPA monotherapy. Significant and positive correlations of GPx and SOD activities and H2O2 and 8-OHdG levels with the age of children at the beginning of treatment were observed. H2O2 levels were also positively correlated with number of seizures before VPA monotherapy. VPA showed significant antioxidant effects decreasing seizure activity, possibly depending on the presence of cerebral structural alterations, treatment time, and age.

Phenytoin-induced choreoathetosis after serial seizures due to traumatic brain injury and chronic alcoholism

Intravenous phenytoin (PHT) for suspected seizures may trigger severe choreoathetosis. Discontinuation of PHT results in immediate and complete resolution of hyperkinesias. Co-medication with valproic acid, levetiracetam, tranquilisers, and anesthetics or alcohol presumably do not modify this adverse effect of PHT. Choreoathetosis can be easily misinterpreted as seizures.

Mitochondrial DNA copy number is associated with psychosis severity and anti-psychotic treatment

Mitochondrial pathology has been implicated in the pathogenesis of psychotic disorders. A few studies have proposed reduced leukocyte mitochondrial DNA (mtDNA) copy number in schizophrenia and bipolar disorder type I, compared to healthy controls. However, it is unknown if mtDNA copy number alteration is driven by psychosis, comorbidity or treatment. Whole blood mtDNA copy number was determined in 594 psychosis patients and corrected for platelet to leukocyte count ratio (mtDNAcn_res). The dependence of mtDNAcn_res on clinical profile, metabolic comorbidity and antipsychotic drug exposure was assessed. mtDNAcn_res was reduced with age (β = −0.210, p < 0.001), use of clozapine (β = −0.110,p = 0.012) and risperidone (β = −0.109,p = 0.014), dependent on prescribed dosage (p = 0.006 and p = 0.026, respectively), and the proportion of life on treatment (p = 0.006). Clozapine (p = 0.0005) and risperidone (p = 0.0126) had a reducing effect on the mtDNA copy number also in stem cell-derived human neurons in vitro at therapeutic plasma levels. For patients not on these drugs, psychosis severity had an effect (β = −0.129, p = 0.017), similar to age (β = −0.159, p = 0.003) and LDL (β = −0.119, p = 0.029) on whole blood mtDNAcn_res. Further research is required to determine if mtDNAcn_res reflects any psychosis-intrinsic mitochondrial changes.