Category Archives: Epilepsy

Anticonvulsive Properties of Cannabidiol in a Model of Generalized Seizure Are Transient Receptor Potential Vanilloid 1 Dependent

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View details for Cannabis and Cannabinoid Research cover image“Highly purified cannabidiol (CBD) (approved as Epidiolex® in the United States) has demonstrated efficacy with an acceptable safety profile in patients with Lennox-Gastaut or Dravet syndrome in four randomized controlled trials. CBD possesses affinity for many target classes with functional effects relevant to the pathophysiology of many disease types, including epilepsy.

Although the mechanism of action of CBD underlying the reduction of seizures in humans is unknown, transient receptor potential vanilloid 1 (TRPV1) represents a plausible target because (1) CBD activates and then desensitizes TRPV1, (2) TRPV1 is overexpressed in models of temporal lobe epilepsy and patients with epilepsy, (3) and TRPV1 modulates neuronal excitability.

Methods: To investigate a potential role of TRPV1 in the anticonvulsive effects of CBD, the effect of CBD on seizure threshold was assessed using a mouse maximal electroshock threshold model of generalized seizure in TRPV1 knockout and wildtype mice. The dose dependence of the CBD effect was determined and compared with that of the positive comparator diazepam and vehicle.

Results: At 50 and 100 mg/kg, CBD significantly (p<0.0001) increased seizure threshold in wildtype mice compared with TRPV1 knockout and vehicle controls. This effect was observed only at 100 mg/kg in TRPV1 knockout mice compared with knockout vehicle mice, in which gene deletion partially attenuated the CBD-increased seizure threshold. The effect of high-dose CBD in wildtype mice was nevertheless significantly different from vehicle-treated TRPV1 knockout mice (p<0.0001). Bioanalysis confirmed that genotype-specific differential brain exposure to CBD was not responsible for the observed effect on seizure threshold.

Conclusion: These data strongly implicate TRPV1 in the potential mechanisms of action for the anticonvulsive effects of CBD. The partial inhibition of the anticonvulsive effect of high-dose CBD in TRPV1 knockout mice may indicate the involvement of targets other than TRPV1. Further characterization of TRPV1 in the anticonvulsive effect of CBD in validated models of seizure is warranted, as is pharmacological investigation of the molecular interaction between CBD and TRPV1.”

https://pubmed.ncbi.nlm.nih.gov/32656346/

https://www.liebertpub.com/doi/10.1089/can.2019.0028

Interactions Between Cannabidiol and Δ 9 -Tetrahydrocannabinol in Modulating Seizure Susceptibility and Survival in a Mousae Model of Dravet Syndrome

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British Journal of Pharmacology “Extracts from the cannabis plant can dramatically improve the health of children suffering from refractory epilepsies such as Dravet syndrome.

These extracts typically contain cannabidiol (CBD), a phytocannabinoid with well-documented anticonvulsant effects, but may also contain Δ9 -tetrahydrocannabinol (Δ9 -THC). It is unclear whether the presence of Δ9 -THC modulates the anticonvulsant efficacy of CBD. Here we utilized the Scn1a+/- mouse model of Dravet syndrome to examine this question.

Key results: Administered alone, CBD (100 mg/kg i.p.) was anticonvulsant against hyperthermia-induced seizures as were low (0.1 and 0.3 mg/kg i.p.) but not higher doses of Δ9 -THC. A subthreshold dose of CBD (12 mg/kg) enhanced the anticonvulsant effects Δ9 -THC (0.1 mg/kg). Subchronic oral administration of Δ9 -THC or CBD alone did not affect spontaneous seizure frequency or mortality while, surprisingly, their co-administration increased the severity of spontaneous seizures and overall mortality.

Conclusion and implications: Low doses of Δ9 -THC are anticonvulsant against hyperthermia-induced seizures in Scn1a+/ mice, effects that are enhanced by a sub-anticonvulsant dose of CBD. However, proconvulsant effects and increased premature mortality are observed when CBD and Δ9 -THC are subchronically dosed in combination. The possible explanations and implications of this are discussed.”

https://pubmed.ncbi.nlm.nih.gov/32608111/

https://bpspubs.onlinelibrary.wiley.com/doi/abs/10.1111/bph.15181

Cannabidiol Efficacy Independent of Clobazam: Meta-Analysis of Four Randomized-Controlled Trials

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 Acta Neurologica Scandinavica“The efficacy of cannabidiol (CBD) with and without concomitant clobazam (CLB) was evaluated in stratified analyses of four large randomized controlled trials, two in Lennox-Gastaut syndrome and two in Dravet syndrome.

Results: The meta-analysis favored CBD vs. placebo regardless of CLB use. The treatment ratio (95% CI) of CBD over placebo for the average reduction in seizure frequency was 0.59 (0.52, 0.68; p<0.0001) with CLB and 0.85 (0.73, 0.98; p=0.0226) without CLB, and the 50% responder rate odds ratio (95% CI) was 2.51 (1.69, 3.71; p<0.0001) with CLB and 2.40 (1.38, 4.16; p=0.0020) without CLB. Adverse events (AEs) related to somnolence, rash, pneumonia, or aggression were more common in patients with concomitant CLB. There was a significant exposure/response relationship for CBD and its active metabolite.

Conclusions: These results indicate CBD is efficacious with and without CLB, but do not exclude the possibility of a synergistic effect associated with the combination of agents. The safety and tolerability profile of CBD without CLB shows a lower rate of certain AEs than with CLB.”

https://pubmed.ncbi.nlm.nih.gov/32592183/

https://onlinelibrary.wiley.com/doi/abs/10.1111/ane.13305

Cannabis Constituents Reduce Seizure Behavior in Chemically-Induced and scn1a-mutant Zebrafish

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Epilepsy and Behavior Journal | Epilepsy Foundation“Current antiepileptic drugs (AEDs) are undesirable for many reasons including the inability to reduce seizures in certain types of epilepsy, such as Dravet syndrome (DS) where in one-third of patients does not respond to current AEDs, and severe adverse effects that are frequently experienced by patients.

Epidiolex, a cannabidiol (CBD)-based drug, was recently approved for treatment of DS. While Epidiolex shows great promise in reducing seizures in patients with DS, it is used in conjunction with other AEDs and can cause liver toxicity. To investigate whether other cannabis-derived compounds could also reduce seizures, the antiepileptic effects of CBD, Δ9-tetrahydrocannabinol (THC), cannabidivarin (CBDV), cannabinol (CBN), and linalool (LN) were compared in both a chemically-induced (pentylenetetrazole, PTZ) and a DS (scn1Lab-/-) seizure models.

Cannabidiol (0.6 and 1 μM) and THC (1 and 4 μM) significantly reduced PTZ-induced total distance moved. At the highest THC concentration, the significant reduction in PTZ-induced behavior was likely the result of sedation as opposed to antiseizure activity.

In the DS model, CBD (0.6 μM), THC (1 μM), CBN (0.6 and 1 μM), and LN (4 μM) significantly reduced total distance traveled. Cannabinol was the most effective at reducing total distance relative to controls. In addition to CBD, other cannabis-derived compounds showed promise in reducing seizure-like activity in zebrafish.

Specifically, four of the five compounds were effective in the DS model, whereas in the PTZ model, only CBD and THC were, suggesting a divergence in the mode of action among the cannabis constituents.”

https://pubmed.ncbi.nlm.nih.gov/32585475/

“In the DS model, CBD, THC, CBN, and LN caused significant reduction in seizure behavior, while THC and CBD were effective in both models.”

https://linkinghub.elsevier.com/retrieve/pii/S1525505020303310

Chronic Cannabidiol Alters Genome-Wide DNA Methylation in Adult Mouse Hippocampus: Epigenetic Implications for Psychiatric Disease

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Environmental and Molecular Mutagenesis“Cannabidiol (CBD) is the primary non-psychoactive compound found in cannabis (Cannabis sativa) and an increasingly popular dietary supplement as a result of widespread availability of CBD-containing products.

CBD is FDA-approved for the treatment of epilepsy and exhibits anxiolytic, antipsychotic, prosocial, and other behavioral effects in animal and human studies, however, the underlying mechanisms governing these phenotypes are still being elucidated. The epigenome, particularly DNA methylation, is responsive to environmental input and can govern persistent patterns of gene regulation affecting phenotype across the life course.

In order to understand the epigenomic activity of chronic cannabidiol exposure in the adult brain, 12-week-old male C57BL/6 mice were exposed to either 20 mg/kg CBD or vehicle daily by oral administration for fourteen days. Hippocampal tissue was collected and reduced-representation bisulfite sequencing (RRBS) was performed. Analyses revealed 3,323 differentially methylated loci (DMLs) in CBD-exposed animals with a small skew toward global hypomethylation.

Genes for cell adhesion and migration, dendritic spine development, and excitatory postsynaptic potential were found to be enriched in a gene ontology term analysis of DML-containing genes, and disease ontology enrichment revealed an overrepresentation of DMLs in gene sets associated with autism spectrum disorder, schizophrenia, and other phenotypes.

These results suggest that the epigenome may be a key substrate for CBD’s behavioral effects and provides a wealth of gene regulatory information for further study.”

https://pubmed.ncbi.nlm.nih.gov/32579259/

https://onlinelibrary.wiley.com/doi/abs/10.1002/em.22396

Cannabidiol Anticonvulsant Effect Is Mediated by the PI3Kγ Pathway

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Neuropharmacology“The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/Akt)/mechanistic target of rapamycin (mTOR) signaling pathway has been associated with several pathologies in the central nervous system (CNS), including epilepsy. There is evidence supporting the hypothesis that the PI3Kγ signaling pathway may mediate the powerful anticonvulsant properties associated with the cannabinoidergic system.

This work aims to investigate if the anticonvulsant and neuroprotective effects of cannabidiol (CBD) are mediated by PI3Kγ.

CDB increased latency and reduced the severity of pilocarpine-induced behavioral seizures, as well as prevented postictal changes, such as neurodegeneration, microgliosis and astrocytosis, in WT animals, but not in PI3Kγ-/-. CBD in vivo effects were abolished by pharmacological inhibition of cannabinoid receptor or mTOR. In vitro, PI3Kγ inhibition or deficiency also changed CBD protection observed in glutamate-induced cell death assay. Thus, we suggest that the modulation of PI3K/mTOR signaling pathway is involved in the anticonvulsant and neuroprotective effects of CBD.

These findings are important not only for the elucidation of the mechanisms of action of CBD, which are currently poorly understood, but also to allow the prediction of therapeutic and side effects, ensuring efficacy and safety in the treatment of patients with epilepsy.”

https://pubmed.ncbi.nlm.nih.gov/32574650/

“CBD is anticonvulsant in a model of pilocarpine-induced behavioral seizures. CB1 receptor mediates the effects of CBD. PI3Kγ pathway mediates the anticonvulsant neuroprotective effects of CBD.”

https://www.sciencedirect.com/science/article/abs/pii/S0028390820302240?via%3Dihub

Current Application of Cannabidiol (CBD) in the Management and Treatment of Neurological Disorders

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SpringerLink“Cannabidiol (CBD), which is nonintoxicating pharmacologically relevant constituents of Cannabis, demonstrates several beneficial effects. It has been found to have antioxidative, anti-inflammatory, and neuroprotective effects. As the medicinal use of CBD is gaining popularity for treatment of various disorders, the recent flare-up of largely unproven and unregulated cannabis-based preparations on medical therapeutics may have its greatest impact in the field of neurology. Currently, as lot of clinical trials are underway, CBD demonstrates remarkable potential to become a supplemental therapy in various neurological conditions. It has shown promise in the treatment of neurological disorders such as anxiety, chronic pain, trigeminal neuralgia, epilepsy, and essential tremors as well as psychiatric disorders. While recent FDA-approved prescription drugs have demonstrated safety, efficacy, and consistency enough for regulatory approval in spasticity in multiple sclerosis (MS) and in Dravet and Lennox-Gastaut Syndromes (LGS), many therapeutic challenges still remain. In the current review, the authors have shed light on the application of CBD in the management and treatment of various neurological disorders.”

https://pubmed.ncbi.nlm.nih.gov/32556748/

https://link.springer.com/article/10.1007%2Fs10072-020-04514-2

Plant Derived Versus Synthetic Cannabidiol: Wishes and Commitment of Epilepsy Patients

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 cannabidiol | www.thctotalhealthcare.com“A special component of cannabis, cannabidiol (CBD), is currently in the focus of epilepsy treatment and research. In this context, we investigated patients’ expectations and preferences pertaining to plant-derived versus synthetic formulation of cannabidiol, as well as their willingness to get this treatment.

Methods: One hundred and four of 153 patients with different forms of epilepsy (54 % female, mean age 40 ± 16 yrs.) responded to the survey. The survey consisted of 8 questions addressing expectations of and concerns towards CBD treatment, preferences of plant-derived versus synthetic CBD, estimated monthly costs, and willingness to buy CBD at one’s own expense.

Results: The majority (73 %) of the responding epilepsy patients wished to receive plant-derived CBD; 5 % preferred synthetic CBD. Reasons for this choice were botanic origin, lack of chemistry, and the assumption of fewer and less dangerous side effects. Eighty-two percent of the patients estimated the monthly costs of CBD treatment to be below €500. Using the willingness-to-pay approach to assess the commitment of patients, 68 % could imagine buying the drug themselves. Fifty-three percent of these would be willing to pay up to €100, 40 % €100 to €200, and another 7 % €200 to €500 per month.

Conclusion: There is an overwhelming preference towards plant-derived cannabidiol in epilepsy patients, driven by the idea of organic substances being safer and better tolerated than synthetic. The willingness-to-pay approach reflects the high burden and pressure of uncontrolled epilepsy and the expectation of relief. Non-realistic ideas of pricing as well as what patients would be willing and able to pay confirm this perception.”

https://pubmed.ncbi.nlm.nih.gov/32554292/

“Epilepsy patients preferred plant-derived cannabidiol to synthetic cannabidiol.”

https://www.seizure-journal.com/article/S1059-1311(20)30175-8/pdf

Effectiveness of Cannabidiol in a Prospective Cohort of Children With Drug-Resistant Epileptic Encephalopathy in Argentina

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“We report our preliminary findings regarding effectiveness, safety, and tolerability of cannabidiol (CBD) added to antiepileptic therapy in a cohort of children with drug-resistant epileptic encephalopathies (EEs) with a mean follow-up of 8.5 months (range, 3-12 months).

Methods: A prospective cohort study was designed with the aim of assessing the effectiveness, safety, and tolerability of the addition of CBD to standard antiseizure medications (ASMs) in children with drug-resistant EE enrolled at a single center (Neurology Department, Hospital de Pediatría “Juan P. Garrahan”, Buenos Aires, Argentina).

Results: Fifty patients were enrolled between October 2018 and October 2019, 49 of whom had a follow-up of at least 3 months at the time this interim analysis was performed. Mean age at enrollment was 10.5 years (range 2-16). Median age at first seizure was 7 months. Up to the last visit of each patient (follow-up 3-12 months) 39/49 children (80 %) had responded to treatment with a decrease in seizure frequency. Overall, 77.6 % of the patients had a seizure reduction of at least 25 %, 73.5 % had a ≥ 50 % reduction, and 49 % had a ≥ 75 % reduction. Mean monthly seizure frequency was reduced from 959 to 381 (median decrease from 299 to 102, range, 38-1900; median decrease 66 %, p < 0.001). All adverse effects were mild or moderate. The most common adverse effect was drowsiness (in 32 %), usually reversed by adjusting clobazam dose (in 12 children).

Conclusion: In children with drug-resistant EEs, CBD oil as an adjuvant therapy to antiepileptic therapy seems safe, well tolerated, and effective.”

https://pubmed.ncbi.nlm.nih.gov/32544657/

“Cannibidiol showed good effectiveness, with a ≥ 50 % reduction in seizure frequency in 73.5 % of the patients. Good results were obtained in patients with Lennox-Gastaut and Dravet syndromes. In epileptic encephalopathies other than Lennox-Gastaut results were also good. Cannabidiol showed good safety and tolerability as all adverse effects were mild or moderate.”

https://www.seizure-journal.com/article/S1059-1311(20)30167-9/pdf

Does Cannabidiol Have Antiseizure Activity Independent of Its Interactions With Clobazam? An Appraisal of the Evidence From Randomized Controlled Trials

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 Epilepsia“Four pivotal randomized placebo-controlled trials have demonstrated that adjunctive therapy with cannabidiol (CBD) improves seizure control in patients with Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS).

Between 47% and 68% of patients allocated to CBD treatment in these trials were receiving clobazam (CLB), which shows complex interactions with CBD resulting, in particular, in a 3.4- to 5-fold increase in plasma concentration of the active metabolite norclobazam. This raises concern as to the role played by these interactions in determining the reduction in seizure frequency in CBD-treated patients, and the question of whether CBD per se has clinically evident antiseizure effects.

We appraised available evidence on the clinical consequences of the CBD-CLB interaction, focusing on subgroup analyses of seizure outcomes in patients on and off CLB comedication in the pivotal CBD trials, as provided by the European Medicines Agency Public Assessment Report.

Evaluation of the results of individual trials clearly showed that improvement in seizure control over placebo was greater when CBD was added on to CLB than when it was added on to other medications. However, seizure control was also improved in patients off CLB, and despite the small sample size the difference vs placebo was statistically significant for the 10 mg/kg/d dose in one of the two LGS trials.

Stronger evidence for an antiseizure effect of CBD independent of an interaction with CLB emerges from meta-analyses of seizure outcomes in the pooled population of LGS and DS patients not receiving CLB comedication.

Although these results need to be interpreted taking into account methodological limitations, they provide the best clinical evidence to date that CBD exerts therapeutic effects in patients with epilepsy that are independent of its interaction with CLB. Greater antiseizure effects, and a greater burden of adverse effects, are observed when CBD is combined with CLB.”

https://pubmed.ncbi.nlm.nih.gov/32452568/

https://onlinelibrary.wiley.com/doi/abs/10.1111/epi.16542