Fish oil attenuates methylmalonate-induced seizures

Pathophysiology of propionic and methylmalonic acidemias. Part 2: Treatment strategies

Despite realizing increased survival rates for propionic acidemia (PA) and methylmalonic acidemia (MMA) patients, the current therapeutic regimen is inadequate for preventing or treating the devastating complications that still can occur. The elucidation of pathophysiology of these complications allows us to evaluate and rethink treatment strategies. In this review we display and discuss potential therapy targets and we give a systematic overview on current, experimental and unexplored treatment strategies in order to provide insight in what we have to offer PA and MMA patients, now and in the future. Evidence on the effectiveness of treatment strategies is often scarce, since none were tested in randomized clinical trials. This raises concerns, since even the current consensus on best practice treatment for PA and MMA is not without controversy. To attain substantial improvements in overall outcome, gene, mRNA or enzyme replacement therapy is most promising since permanent reduction of toxic metabolites allows for a less strict therapeutic regime. Hereby, both mitochondrial-associated and therapy induced complications can theoretically be prevented. However, the road from bench to bedside is long, as it is challenging to design a drug that is delivered to the mitochondria of all tissues that require enzymatic activity, including the brain, without inducing any off-target effects. To improve survival rate and quality of life of PA and MMA patients, there is a need for systematic (re-)evaluation of accepted and potential treatment strategies, so that we can better determine who will benefit when and how from which treatment strategy.

Effect of Chronic Krill Oil Supplement on Seizures Induced by Pentylenetetrazole in the Hippocampus of Adult Rats with Previous Febrile Seizures

We evaluated the effect of krill oil (KO) supplement on seizures induced by pentylenetetrazole (PTZ) in animals with previous febrile seizures (FSs) induced by hyperthermia to determine its effectiveness in seizure susceptibility and as an anticonvulsant. Male Wistar rats with FS separated into water (W, 1 mL), palm oil (PO, 300 mg/kg, total volume 1 mL), or KO (300 mg/kg, total volume 1 mL) groups. All drugs were administered chronically via the intragastric route. Electrical activity was recorded by intracranial EEG simultaneously with convulsive behavior. All animals' brains were processed by immunofluorescence against GFAP, NeuN, and connexins (Cx); cellular quantification was performed in hippocampus and pyramidal or granular layer thickness was evaluated with cresyl violet (CV) staining. The results showed a significant delay in convulsive behavior and a slight increased survival time after PTZ administration in the group treated with KO compared with PO and W groups. The epileptiform activity showed high amplitude and frequency, with no significant differences between groups, nor were there differences in the number and duration of discharge trains. KO and PO increased the number of astrocytes and the number of neurons compared with the W group. KO and PO decreased the expression of Cx36 without affecting Cx43 expression or the thickness of layers. Based on these data, we consider it important to perform more experiments to determine the anticonvulsant role of KO, taking into account the partial effect found in this study. KO could be used as a coadjuvant of traditional anticonvulsive treatments. PRACTICAL APPLICATION: In this study was evaluated the anticonvulsive effect of a chronic krill oil (KO) supplement in animals with seizures. Results showed that KO had partial anticonvulsive effects measured by EEG activity and convulsive behavior analysis. These data justify further research that looks at KO supplementation as a prospective coadjuvant of pharmacologic management of seizure disorder.

Functional Nutrients for Epilepsy

Epilepsy is a common neurological disorder of which seizures are a core symptom. Approximately one third of epileptic patients are resistant to antiepileptic drugs and therefore require alternative therapeutic options. Dietary and nutritional supplements can in some cases replace drugs, but with the exception of ketogenic diets, there are no officially recommended dietary considerations for patients with epilepsy. In this review we summarize a selection of nutritional suggestions that have proved beneficial in treating different types of epilepsy. We describe the types of seizures and epilepsy and follow this with an introduction to basic molecular mechanisms. We then examine several functional nutrients for which there is clinical evidence of therapeutic efficacy in reducing seizures or epilepsy-associated sudden death. We also discuss experimental results that demonstrate possible molecular mechanisms elicited by the administration of various nutrients. The availability of multiple dietary and nutritional candidates that show favorable outcomes in animals implies that assessing the clinical potential of these substances will improve translational medicine, ultimately benefitting epilepsy patients.

Dietary Omega-3 Polyunsaturated Fatty Acid Deprivation Does Not Alter Seizure Thresholds but May Prevent the Anti-seizure Effects of Injected Docosahexaenoic Acid in Rats

Background: Brain concentrations of omega-3 docosahexaenoic acid (DHA, 22:6n-3) have been reported to positively correlate with seizure thresholds in rodent seizure models. It is not known whether brain DHA depletion, achieved by chronic dietary omega-3 polyunsaturated fatty acid (PUFA) deficiency, lowers seizure thresholds in rats.

Objective: The present study tested the hypothesis that lowering brain DHA concentration with chronic dietary n-3 PUFA deprivation in rats will reduce seizure thresholds, and that compared to injected oleic acid (OA), injected DHA will raise seizure thresholds in rats maintained on n-3 PUFA adequate and deficient diets.

Methods: Rats (60 days old) were surgically implanted with electrodes in the amygdala, and subsequently randomized to the AIN-93G diet containing adequate levels of n-3 PUFA derived from soybean oil or an n-3 PUFA-deficient diet derived from coconut and safflower oil. The rats were maintained on the diets for 37 weeks. Afterdischarge seizure thresholds (ADTs) were measured every 4–6 weeks by electrically stimulating the amygdala. Between weeks 35 and 37, ADTs were assessed within 1 h of subcutaneous OA or DHA injection (600 mg/kg). Seizure thresholds were also measured in a parallel group of non-implanted rats subjected to the maximal pentylenetetrazol (PTZ, 110 mg/kg) seizure test. PUFA composition was measured in the pyriform-amygdala complex of another group of non-implanted rats sacrificed at 16 and 32 weeks.

Results: Dietary n-3 PUFA deprivation did not significantly alter amygdaloid seizure thresholds or latency to PTZ-induced seizures. Acute injection of OA did not alter amygdaloid ADTs of rats on the n-3 PUFA adequate or deficient diets, whereas acute injection of DHA significantly increased amygdaloid ADTs in rats on the n-3 PUFA adequate control diet as compared to rats on the n-3 PUFA deficient diet (P < 0.05). Pyriform-amygdala DHA percent composition did not significantly differ between the groups, while n-6 docosapentaenoic acid, a marker of n-3 PUFA deficiency, was significantly increased by 2.9-fold at 32 weeks.

Conclusion: Chronic dietary n-3 PUFA deficiency does not alter seizure thresholds in rats, but may prevent the anti-seizure effects of DHA.

Combined malonic and methylmalonic aciduria due to ACSF3 mutations: Benign clinical course in an unselected cohort

BACKGROUND

The clinical significance of combined malonic and methylmalonic aciduria due to ACSF3 deficiency (CMAMMA) is controversial. In most publications, affected patients were identified during the investigation of various complaints.

METHODS

Using a cross-sectional multicenter retrospective natural history study, we describe the course of all known CMAMMA individuals in the province of Quebec.

RESULTS

We identified 25 CMAMMA patients (6 months to 30 years old) with a favorable outcome regardless of treatment. All but one came to clinical attention through the Provincial Neonatal Urine Screening Program (screening on day 21 of life). Median methylmalonic acid (MMA) levels ranged from 107 to 857 mmol/mol creatinine in urine (<10) and from 8 to 42 μmol/L in plasma (<0.4); median urine malonic acid (MA) levels ranged from 9 to 280 mmol/mol creatinine (<5). MMA was consistently higher than MA. These findings are comparable to those previously reported in CMAMMA. Causal ACSF3 mutations were identified in all patients for whom genotyping was performed (76% of cases). The most common ACSF3 mutations in our cohort were c.1075G > A (p.E359K) and c.1672C > T (p.R558W), representing 38.2 and 20.6% of alleles in genotyped families, respectively; we also report several novel mutations.

CONCLUSION

Because our province still performs urine newborn screening, our patient cohort is the only one free of selection bias. Therefore, the favorable clinical course observed suggests that CMAMMA is probably a benign condition, although we cannot exclude the possibility that a small minority of patients may present symptoms attributable to CMAMMA, perhaps as a result of interactions with other genetic or environmental factors.

Mice lacking L-12/15-lipoxygenase show increased mortality during kindling despite demonstrating resistance to epileptogenesis

Objective

Studies have addressed the potential involvement of L-12/15-lipoxygenases (LOs), a polyunsaturated fatty acid metabolizing enzyme, in experimental models of acute stroke and chronic neurodegeneration; however, none to our knowledge has explored its role in epilepsy development. Thus, this study characterizes the cell-specific expression of L-12/15 -LO in the brain and examines its contribution to epileptogenesis.

Methods

L-12/15-LO messenger RNA (mRNA) and protein expression and activity were characterized via polymerase chain reaction (PCR), immunocytochemistry and enzyme-linked immunosorbent assay (ELISA), respectively. To assess its role in epileptogenesis, L-12/15 -LO-deficient mice and their wild-type littermates were treated with pentylenetetrazole (PTZ, ip) every other day for up to 43 days (kindling paradigm). The innate seizure threshold was assessed by the acute PTZ-induced seizure response of naive mice.

Results

L-12/15 -LO mRNA is expressed in hippocampal and cortical tissue from wild-type C57BL/6 mice. In addition, it is physically and functionally expressed by microglia, neurons, and brain microvessel endothelial cells, but not by astrocytes. Mice deficient in L-12/15 -LO were resistant to PTZ-induced kindling and demonstrated an elevated innate seizure threshold. Despite this, a significant increase in seizure-related mortality was observed during the kindling paradigm in L-12/15 -LO nulls relative to their wild-type littermates.

Significance

The present study is the first to detail the role of L-12/15-LO in the epileptogenic process. The results suggest that constitutive L-12/15-LO expression contributes to a lower innate set point for PTZ acute seizure generation, translating to higher rates of kindling acquisition. Nevertheless, increased seizure-related deaths in mice lacking activity of L-12/15-LO suggests that its products may influence endogenous mechanisms involved in termination of seizure activity.

In-Depth Study of the Interaction, Sensitivity, and Gating Modulation by PUFAs on K+ Channels; Interaction and New Targets

Voltage gated potassium channels (K_V) are membrane proteins that allow selective flow of K⁺ ions in a voltage-dependent manner. These channels play an important role in several excitable cells as neurons, cardiomyocytes, and vascular smooth muscle. Over the last 20 years, it has been shown that omega-3 polyunsaturated fatty acids (PUFAs) enhance or decrease the activity of several cardiac K_V channels. PUFAs-dependent modulation of potassium ion channels has been reported to be cardioprotective. However, the precise cellular mechanism underlying the cardiovascular benefits remained unclear in part because new PUFAs targets and signaling pathways continue being discovered. In this review, we will focus on recent data available concerning the following aspects of the K_V channel modulation by PUFAs: (i) the exact residues involved in PUFAs-K_V channels interaction; (ii) the structural PUFAs determinants important for their effects on K_V channels; (iii) the mechanism of the gating modulation of K_V channels and, finally, (iv) the PUFAs modulation of a few new targets present in smooth muscle cells (SMC), K_Ca1.1, K_2P, and K_ATP channels, involved in vascular relaxation.

Omega 3 polyunsaturated fatty acids enhance the protective effect of levetiracetam against seizures, cognitive impairment and hippocampal oxidative DNA damage in young kindled rats

Levetiracetam (LEV) is a unique, effective, relatively safe antiepileptic drug that preferentially interacts with synaptic vesicle protein 2A (SV2A). This study aimed to explore the effect of combined treatment of LEV with omega 3 (OM3) on cognitive impairment and hippocampal oxidative stress and DNA damage induced by seizures in the PTZ-kindled young rat model. Cognitive functions, biomarkers of oxidative stress, and DNA damage were assessed in PTZ-kindled young rats pretreated with single and combined treatment of LEV (30mg/kg, i.p.) and OM3 (200mg/kg, p.o.). Pretreatment with LEV and OM3 at the tested doses significantly attenuated PTZ-induced seizures and decreased cognitive impairment in both passive avoidance and elevated plus maze tests in the PTZ-kindled rats. Moreover, the increase in hippocampal glutamate, malondialdehyde and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels, as well as the decrease in reduced glutathione (GSH) levels and GSH-peroxidase and superoxide dismutase activities induced by PTZ kindling, significantly decreased. These effects were higher with combined treatment of LEV with OM3 and significantly more than the observed effects of single LEV or OM3. In conclusion, the combined treatment of LEV with OM3 is more effective in seizure control and alleviating the cognitive impairment induced by PTZ kindling in the young rat model, the effects that result from the decrease in hippocampal oxidative stress and DNA damage which can be attributed to the antioxidant properties of both LEV and OM3. These results may be promising for the use of LEV and OM3 combination in the treatment of epileptic children.

Monoterpenoid terpinen-4-ol exhibits anticonvulsant activity in behavioural and electrophysiological studies

Terpinen-4-ol (4TRP) is a monoterpenoid alcoholic component of essential oils obtained from several aromatic plants. We investigated the psychopharmacological and electrophysiological activities of 4TRP in male Swiss mice and Wistar rats. 4TRP was administered intraperitoneally (i.p.) at doses of 25 to 200 mg/kg and intracerebroventricularly (i.c.v.) at concentrations of 10, 20, and 40 ng/2 μL. For in vitro experiments, 4TRP concentrations were 0.1 mM and 1.0 mM. 4TRP (i.p.) inhibited pentylenetetrazol- (PTZ-) induced seizures, indicating anticonvulsant effects. Electroencephalographic recordings showed that 4TRP (i.c.v.) protected against PTZ-induced seizures, corroborating the behavioural results. To determine whether 4TRP exerts anticonvulsant effects via regulation of GABAergic neurotransmission, we measured convulsions induced by 3-mercapto-propionic acid (3-MP). The obtained results showed involvement of the GABAergic system in the anticonvulsant action exerted by 4TRP, but flumazenil, a selective antagonist of the benzodiazepine site of the GABA_A receptor, did not reverse the anticonvulsant effect, demonstrating that 4TRP does not bind to the benzodiazepine-binding site. Furthermore, 4TRP decreased the sodium current through voltage-dependent sodium channels, and thus its anticonvulsant effect may be related to changes in neuronal excitability because of modulation of these channels.

Long-term fish oil supplementation attenuates seizure activity in the amygdala induced by 3-mercaptopropionic acid in adult male rats

Several studies have provided evidence of significant effects of omega-3 fatty acids on brain functionality, including seizures and disorders such as epilepsy. Fish oil (FO) is a marine product rich in unsaturated omega-3 fatty acids. Considering that the amygdala is one of the brain structures most sensitive to seizure generation, we aimed to evaluate the effect of long-term chronic FO supplementation (from embryonic conception to adulthood) on the severity of seizures and amygdaloid electroencephalographic activity (EEG) in a 3-mercaptopropionic acid (3-MPA)-induced seizure model using adult rats. Female Wistar rats were fed a commercial diet supplemented daily with FO (300mg/kg) from puberty through mating, gestation, delivery, and weaning of the pups. Only the male pups were then fed daily with a commercial diet supplemented with the same treatment as the dam up to the age of 150days postpartum, when they were bilaterally implanted in the amygdala to record behavior and EEG activity before, during, and after seizures induced by administering 3-MPA. Results were compared with those obtained from rats supplemented with palm oil (PO) and rats treated with a vehicle (CTRL). The male rats treated with FO showed longer latency to seizure onset, fewer convulsive episodes, and attenuated severity compared those in the PO and CTRL groups according to the Racine scale. Moreover, long-term FO supplementation was associated with a reduction of the absolute power (AP) of the fast frequencies (12-25Hz) in the amygdala during the seizure periods. These findings support the idea that chronic supplementation with omega-3 of marine origin may have antiseizure properties as other studies have suggested.

Intraperitoneal administration of docosahexaenoic acid for 14days increases serum unesterified DHA and seizure latency in the maximal pentylenetetrazol model

Docosahexaenoic acid (DHA) is an omega-3 polyunsaturated fatty acid (n-3 PUFA) which has been shown to raise seizure thresholds following acute administration in rats. The aims of the present experiment were the following: 1) to test whether subchronic DHA administration raises seizure threshold in the maximal pentylenetetrazol (PTZ) model 24h following the last injection and 2) to determine whether the increase in seizure threshold is correlated with an increase in serum and/or brain DHA. Animals received daily intraperitoneal (i.p.) injections of 50mg/kg of DHA, DHA ethyl ester (DHA EE), or volume-matched vehicle (albumin/saline) for 14days. On day 15, one subset of animals was seizure tested in the maximal PTZ model (Experiment 1). In a separate (non-seizure tested) subset of animals, blood was collected, and brains were excised following high-energy, head-focused microwave fixation. Lipid analysis was performed on serum and brain (Experiment 2). For data analysis, the DHA and DHA EE groups were combined since they did not differ significantly from each other. In the maximal PTZ model, DHA significantly increased seizure latency by approximately 3-fold as compared to vehicle-injected animals. This increase in seizure latency was associated with an increase in serum unesterified DHA. Total brain DHA and brain unesterified DHA concentrations, however, did not differ significantly in the treatment and control groups. An increase in serum unesterified DHA concentration reflecting increased flux of DHA to the brain appears to explain changes in seizure threshold, independent of changes in brain DHA concentrations.