Therapeutic effects of cannabinoids in animal models of seizures, epilepsy, epileptogenesis, and epilepsy-related neuroprotection

The anxiolytic effects of cannabinoids: A comprehensive review

Cannabinoids, notably cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC), have emerged as promising candidates for anxiety disorder treatment, supported by both preclinical and clinical evidence. CBD exhibits notable anxiolytic effects with a favourable safety profile, though concerns regarding mild side effects and drug interactions remain. Conversely, THC, the primary psychoactive compound, presents a range of side effects, underscoring the importance of careful dosage management and individualized treatment strategies. So far there are no FDA approved cannabinoid medications for anxiety. The review highlights challenges in cannabinoid research, including dosage variability, variable preclinical data, and limited long-term data. Despite these limitations, cannabinoids represent a promising avenue for anxiety management, with the potential for further optimization in formulation, dosing protocols, and consideration of interactions with conventional therapies. Addressing these challenges could pave the way for novel and personalized approaches to treating anxiety disorders using cannabinoid-based therapies.

The Development of Cannabinoids as Therapeutic Agents in the United States

Cannabis is one of the oldest and widely used substances in the world. Cannabinoids within the cannabis plant, known as phytocannabinoids, mediate cannabis' effects through interactions with the body's endogenous cannabinoid system. This endogenous system, the endocannabinoid system, has important roles in physical and mental health. These roles point to the potential to develop cannabinoids as therapeutic agents while underscoring the risks related to interfering with the endogenous system during nonmedical use. This scoping narrative review synthesizes the current evidence for both the therapeutic and adverse effects of the major (i.e., Δ9-tetrahydrocannabinol and cannabidiol) and lesser studied minor phytocannabinoids, from nonclinical to clinical research. We pay particular attention to the areas where evidence is well established, including analgesic effects after acute exposures and neurocognitive risks after acute and chronic use. In addition, drug development considerations for cannabinoids as therapeutic agents within the United States are reviewed. The proposed clinical study design considerations encourage methodological standards for greater scientific rigor and reproducibility to ultimately extend our knowledge of the risks and benefits of cannabinoids for patients and providers. SIGNIFICANCE STATEMENT: This work provides a review of prior research related to phytocannabinoids, including therapeutic potential and known risks in the context of drug development within the United States. We also provide study design considerations for future cannabinoid drug development.

The Role of Ion Channels and Intracellular Signaling Cascades in the Inhibitory Action of WIN 55,212-2 upon Hyperexcitation

Gi-coupled receptors, particularly cannabinoid receptors (CBRs), are considered perspective targets for treating brain pathologies, including epilepsy. However, the precise mechanism of the anticonvulsant effect of the CBR agonists remains unknown. We have found that WIN 55,212-2 (a CBR agonist) suppresses the synchronous oscillations of the intracellular concentration of Ca2+ ions (epileptiform activity) induced in the neurons of rat hippocampal neuron-glial cultures by bicuculline or NH4Cl. As we have demonstrated, the WIN 55,212-2 effect is mediated by CB1R receptors. The agonist suppresses Ca2+ inflow mediated by the voltage-gated calcium channels but does not alter the inflow mediated by NMDA, AMPA, and kainate receptors. We have also found that phospholipase C (PLC), protein kinase C (PKC), and G-protein-coupled inwardly rectifying K+ channels (GIRK channels) are involved in the molecular mechanism underlying the inhibitory action of CB1R activation against epileptiform activity. Thus, our results demonstrate that the antiepileptic action of CB1R agonists is mediated by different intracellular signaling cascades, including non-canonical PLC/PKC-associated pathways.

Therapeutic potential of CB1R activation by Qingyangshen glycoside M1 for seizure relief

ETHNOPHARMACOLOGICAL RELEVANCE

Cynanchum otophyllum C.K.Schneid.PI.Wilson, commonly referred as ''Qingyangshen'' (QYS), is a traditional folk medicine from Yunnan, renowned for its efficacy in neurological and psychiatric disorders. Glycosides isolated from QYS have shown promise in alleviating epilepsy, however, mechanisms of action and specific molecular targets remain to be elucidated.

AIM OF THE STUDY

The study aimed to evaluate the anticonvulsant effects of Qingyangshen glycosides M1 (M1), a C21 steroidal glycoside from QYS, on pentylenetetrazol (PTZ)-induced convulsions in zebrafish (Danio rerio), and its neuroprotective effect on Glutamate (Glu)-induced damage to PC12 cells, and importantly to identify its potential molecular targets.

MATERIALS AND METHODS

To evaluate anticonvulsant activity of M1, 7 days-post-fertilization (7-dpf) animals were pretreated (by immersion) and then exposed to PTZ (10 mM) solution. Furthermore, Glu-induced PC12 cell damage was employed to investigate the neuroprotective and anti-apoptotic capacity. Cells were pretreated with various concentrations of M1 (0-10 μM) for 12 h and then co-treated with Glu (15 mM) for an additional 24 h. The cell viability, apoptosis rate and apoptosis-related proteins (p-PI3K, PI3K, Akt, p-Akt, CREB, p-CREB, BDNF, Bax and Bcl-2) were measured using CCK-8, annexin V/PI and Western blot assays. To model the expected interaction between M1 and candidate cannabinoid receptor type 1 (CB1R), ERK phosphorylation, molecular docking, and drug affinity responsive target stability (DARTS) techniques were employed. Finally, CB1R antagonist Rimonabant (Rim) was validated by co-administration in both zebrafish and cells to confirm the requirement of CB1R for M1 efficacy.

RESULTS

At a concentration of 400 μM, M1 dramatically reversed PTZ-induced convulsive-like behaviors in zebrafish, as evidenced by a significant reduction in locomotor activity. In the context of Glu-induced cytotoxicity, M1 (10 μM) demonstrated a notable increase in cell viability and suppressed apoptosis through modulation of the Bax/Bcl-2 ratio and activation of the PI3K/Akt/CREB/BDNF signaling axis. These effects were facilitated through CB1R activation. In contrast, Rim dampened the beneficial activities of M1 as a cannabinoid agonist.

CONCLUSIONS

These results demonstrated that M1 as a potential CB1R activator, exhibiting anticonvulsive effects in a PTZ-induced zebrafish model and neuroprotective properties via the PI3K/Akt/CREB/BDNF signaling axis in a Glu-induced PC12 cell injury model. Notably, the observed seizure relief attenuated by CB1R chemical antagonism.

In silico exploration of CB2 receptor agonist in the management of neuroinflammatory conditions by pharmacophore modeling

Endocannabinoid system plays a pivotal role in controlling neuroinflammation, and modulating this system may not only aid in managing symptoms of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Multiple sclerosis, Epilepsy, Central and Peripheral neuropathic pain, but also, have the potential to target these diseases at an early-stage. In the present study, six different pharmacophore hypotheses were generated from Cannabidiol (CBD)-Cannabinoid Receptor subtype-2 (CB2) and then Zinc database was screened for identification of hit molecules. Identified 215 hit molecules were subjected to preliminary screening with ADMET and drug likeness properties, and about 48 molecules were found with no violations and toxicity properties. In molecular docking studies, six compounds showed better binding energy than CBD and β-caryophyllene (known inhibitor of CB2). These six molecules were designated as leads and subjected to re-docking with glide tool and Lead1 (ZINC000078815430) showed docking score of -9.877 kcal/mol, whereas CBD and β-caryophyllene showed score of -9.664 and -8.499 kcal/mol, respectively. Lead1 and CBD were evaluated for stability studies with Desmond tool by molecular dynamic simulation studies. Lead1 showed better stability than CBD in all studied parameters such as RMSD, RMSF, SSE, Rg, SASA, etc. In MM-GBSA free energy calculations, ΔGbinding energy of CB2-CBD complex and CB2-Lead1 were found to be -103.13±11.19 and -107.94±5.42 kcal/mol, respectively. Six lead molecules stated in the study hold promise with respect to CBD agonistic activity for treating and/or managing chronic conditions and can be explored as an alternative for early-stage cure, which has not yet been experimentally explored.

Cannabidiol is a behavioral modulator in BTBR mouse model of idiopathic autism

Introduction

The prevalence of Autism Spectrum Disorder (ASD) has drastically risen over the last two decades and is currently estimated to affect 1 in 36 children in the U.S., according to the center for disease control (CDC). This heterogenous neurodevelopmental disorder is characterized by impaired social interactions, communication deficits, and repetitive behaviors plus restricted interest. Autistic individuals also commonly present with a myriad of comorbidities, such as attention deficit hyperactivity disorder, anxiety, and seizures. To date, a pharmacological intervention for the treatment of core autistic symptoms has not been identified. Cannabidiol (CBD), the major nonpsychoactive constituent of Cannabis sativa, is suggested to have multiple therapeutic applications, but its effect(s) on idiopathic autism is unknown. We hypothesized that CBD will effectively attenuate the autism-like behaviors and autism-associated comorbid behaviors in BTBR T+Itpr3tf/J (BTBR) mice, an established mouse model of idiopathic ASD.

Methods

Male BTBR mice were injected intraperitoneally with either vehicle, 20 mg/kg CBD or 50 mg/kg CBD daily for two weeks beginning at postnatal day 21 ± 3. On the final treatment day, a battery of behavioral assays were used to evaluate the effects of CBD on the BTBR mice, as compared to age-matched, vehicle-treated C57BL/6 J mice.

Results

High dose (50 mg/kg) CBD treatment attenuated the elevated repetitive self-grooming behavior and hyperlocomotion in BTBR mice. The social deficits exhibited by the control BTBR mice were rescued by the 20 mg/kg CBD treatment.

Discussion

Our data indicate that different doses for CBD are needed for treating specific ASD-like behaviors. Together, our results suggest that CBD may be an effective drug to ameliorate repetitive/restricted behaviors, social deficits, and autism-associated hyperactivity.

Acute toxic hippocampal encephalopathy in heavy cannabis users: A case report

Cannabis use is increasing rapidly among young people worldwide despite the deleterious effects of this toxic substance on health. We report a case of acute hippocampal encephalopathy in a heavy cannabis user (8-10 joints/d for 6 years) who presented with a nonfebrile status epilepticus. Brain magnetic resonance imaging revealed bilateral and symmetrical high-signal abnormalities in the hippocampal regions. The damage to these regions is often severe, long-lasting, and sometimes irreversible. Therefore, every doctor (emergency doctor, resuscitator, neurologist...) is asked to request a brain MRI in case of neurological signs in a young cannabis user.

Binding of the monoacylglycerol lipase (MAGL) radiotracer [3H]T-401 in the rat brain after status epilepticus

OBJECTIVES

Monoacylglycerol lipase (MAGL) is a cytosolic serine hydrolase considered a potential novel drug target for the treatment of CNS disorders including epilepsy. Here we examined MAGL levels in a rat model of epilepsy.

METHODS

Autoradiography has been used to validate the binding properties of the MAGL radiotracer, [3H]T-401, in the rat brain, and to explore spatial and temporal changes in binding levels in a model of temporal lobe epilepsy model using unilateral intra-hippocampal injections of kainic acid (KA) in rats.

RESULTS

Specific and saturable binding of [3H]T-401 was detected in both cortical grey and subcortical white matter. Saturation experiments revealed a KD in the range between 15 nM and 17 nM, and full saturation was achieved at concentrations around 30 nM. The binding could be completely blocked with the cold ligand (Ki 44.2 nM) and at higher affinity (Ki 1.27 nM) with another structurally different MAGL inhibitor, ABD 1970. Bilateral reduction in [3H]T-401 binding was observed in the cerebral cortex and the hippocampus few days after status epilepticus that further declined to a level of around 30% compared to the control. No change in binding was observed in either the hypothalamus nor the white matter at any time point. Direct comparison to [3H]UCB-J binding to synaptic vesicle glycoprotein 2 A (SV2A), another protein localized in the pre-synapse, revealed that while binding to MAGL remained low in the chronic phase, SV2A was increased significantly in some cortical areas.

SIGNIFICANCE

These data show that MAGL is reduced in the cerebral cortex and hippocampus in a chronic epilepsy model and indicate that MAGL inhibitors may further reduce MAGL activity in the treatment resistant epilepsy patient.

Traumatic Brain Injury Outcomes After Recreational Cannabis Use

Purpose

Basic science data indicate potential neuroprotective effects of cannabinoids in traumatic brain injury (TBI). We aimed to evaluate the effects of pre-TBI recreational cannabis use on TBI outcomes.

Patients and Methods

We used i2b2 (a scalable informatics framework; www.i2b2.org) to identify all patients presenting with acute TBI between 1/1/2014 and 12/31/2016, then conducted a double-abstraction medical chart review to compile basic demographic, urine drug screen (UDS), Glasgow Coma Scale (GCS), and available outcomes data (mortality, modified Rankin Scale (mRS), duration of stay, disposition (home, skilled nursing facility, inpatient rehabilitation, other)) at discharge and at specific time points thereafter. We conducted multivariable nested ordinal and logistic regression analyses to estimate associations between cannabis use, other UDS results, demographic factors, and selected outcomes.

Results

i2b2 identified 6396 patients who acutely presented to our emergency room with TBI. Of those, 3729 received UDS, with 22.2% of them testing positive for cannabis. Mortality was similar in patients who tested positive vs negative for cannabis (3.9% vs 4.8%; p = 0.3) despite more severe GCS on admission in the cannabis positive group (p = 0.045). Several discharge outcome measures favored the cannabis positive group who had a higher rate of discharge home vs other care settings (p < 0.001), lower discharge mRS (p < 0.001), and shorter duration of hospital stay (p < 0.001) than the UDS negative group. Multivariable analyses confirmed mostly independent associations between positive cannabis screen and these post-TBI short- and long-term outcomes.

Conclusion

This study adds evidence about the potentially neuroprotective effects of recreational cannabis for short- and long-term post-TBI outcomes. These results need to be confirmed via prospective data collections.

The longitudinal effects of cannabidiol on brain temperature in patients with treatment-resistant epilepsy

Neuroinflammation (NI) is a key pathophysiological contributor to treatment-resistant epilepsy (TRE) that remains challenging to observe in vivo. Magnetic resonance spectroscopic imaging and thermometry (MRSI-t) is an emerging technique that can be used to non-invasively map brain temperature, whereby brain temperature elevations serve as a surrogate for the cellular and biochemical processes associated with NI. In a previous multimodal imaging study of focal epilepsy patients, we observed MRSI-t-based brain temperature elevations ipsilateral to the seizure onset zone (SOZ) that were concordant with evidence of edema (Sharma et al., 2023). Despite its potential as tool, it is unclear if MRSI-t can monitor changes in brain temperature in response to treatment. We imaged 25 participants approximately 12-weeks apart. Eight patients with TRE were imaged before receiving highly-purified pharmaceutical grade cannabidiol (CBD; pre-CBD) and after 12-weeks of CBD (on-CBD) therapy. Seventeen healthy controls (HCs) were also imaged twice. Repeated measures t-tests computed changes in TRE patients' seizure symptoms, mood, and brain temperature within their respective SOZs. Repeated measures ANOVAs tested Group*Time changes in imaging data. Participants with TRE had abnormally high peak brain temperatures within their SOZs that decreased after CBD initiation (p < 0.0001). Seizure severity scores also improved after CBD initiation (p < 0.001). These findings provide insights into the possible neural effects of CBD, and further demonstrate MRSI-t's potential as a tool for delineating SOZ. Further investigations into MRSI-t as a longitudinal measure of therapy-induced changes in NI are warranted.

Alterations of auditory sensory gating in mice with noise-induced tinnitus treated with nicotine and cannabis extract

Tinnitus is a phantom sound perception affecting both auditory and limbic structures. The mechanisms of tinnitus remain unclear and it is debatable whether tinnitus alters attention to sound and the ability to inhibit repetitive sounds, a phenomenon also known as auditory gating. Here we investigate if noise exposure interferes with auditory gating and whether natural extracts of cannabis or nicotine could improve auditory pre-attentional processing in noise-exposed mice. We used 22 male C57BL/6J mice divided into noise-exposed (exposed to a 9-11 kHz narrow band noise for 1 h) and sham (no sound during noise exposure) groups. Hearing thresholds were measured using auditory brainstem responses, and tinnitus-like behavior was assessed using Gap prepulse inhibition of acoustic startle. After noise exposure, mice were implanted with multi-electrodes in the dorsal hippocampus to assess auditory event-related potentials in response to paired clicks. The results showed that mice with tinnitus-like behavior displayed auditory gating of repetitive clicks, but with larger amplitudes and longer latencies of the N40 component of the aERP waveform. The combination of cannabis extract and nicotine improved the auditory gating ratio in noise-exposed mice without permanent hearing threshold shifts. Lastly, the longer latency of the N40 component appears due to an increased sensitivity to cannabis extract in noise-exposed mice compared to sham mice. The study suggests that the altered central plasticity in tinnitus is more sensitive to the combined actions on the cholinergic and the endocannabinoid systems. Overall, the findings contribute to a better understanding of pharmacological modulation of auditory sensory gating.

Investigating Owner Use of Dietary Supplements in Dogs with Canine Cognitive Dysfunction

Canine cognitive dysfunction (CCD) is becoming increasingly recognized in veterinary medicine, as dogs live longer and with CCD being highly prevalent among the elderly dog population. Various studies have shown that diet and dietary supplementation can positively influence the clinical signs of CCD, especially if given at an early stage. The aim of this study was to investigate owner use of dietary supplements (DSs) in dogs with age-related behavioral changes. An observational study based on an online questionnaire for owners of dogs with age-related behavioral changes was performed. Out of a total of 394 owners who completed the survey, after noticing age-related behavioral changes, over half of the dogs received DSs (54%), whereas only 8% reported changing their dog's base diet. The most used DS was fish oil (48%). The use of DSs should be discussed with and monitored by veterinary surgeons since many geriatric patients have multi-morbidities, may have specific nutritional requirements and receive multi-faceted medications.

Pharmacological diversity amongst approved and emerging antiseizure medications for the treatment of developmental and epileptic encephalopathies

Developmental and epileptic encephalopathies (DEEs) are rare neurodevelopmental disorders characterised by early-onset and often intractable seizures and developmental delay/regression, and include Dravet syndrome and Lennox-Gastaut syndrome (LGS). Rufinamide, fenfluramine, stiripentol, cannabidiol and ganaxolone are antiseizure medications (ASMs) with diverse mechanisms of action that have been approved for treating specific DEEs. Rufinamide is thought to suppress neuronal hyperexcitability by preventing the functional recycling of voltage-gated sodium channels from the inactivated to resting state. It is licensed for adjunctive treatment of seizures associated with LGS. Fenfluramine increases extracellular serotonin levels and may reduce seizures via activation of specific serotonin receptors and positive modulation of the sigma-1 receptor. Fenfluramine is licensed for adjunctive treatment of seizures associated with Dravet syndrome and LGS. Stiripentol is a positive allosteric modulator of type-A gamma-aminobutyric acid (GABAA) receptors. As a broad-spectrum inhibitor of cytochrome P450 enzymes, its antiseizure effects may additionally arise through pharmacokinetic interactions with co-administered ASMs. Stiripentol is licensed for treating seizures associated with Dravet syndrome in patients taking clobazam and/or valproate. The mechanism(s) of action of cannabidiol remains largely unclear although multiple targets have been proposed, including transient receptor potential vanilloid 1, G protein-coupled receptor 55 and equilibrative nucleoside transporter 1. Cannabidiol is licensed as adjunctive treatment in conjunction with clobazam for seizures associated with Dravet syndrome and LGS, and as adjunctive treatment of seizures associated with tuberous sclerosis complex. Like stiripentol, ganaxolone is a positive allosteric modulator at GABAA receptors. It has recently been licensed in the USA for the treatment of seizures associated with cyclin-dependent kinase-like 5 deficiency disorder. Greater understanding of the causes of DEEs has driven research into the potential use of other novel and repurposed agents. Putative ASMs currently in clinical development for use in DEEs include soticlestat, carisbamate, verapamil, radiprodil, clemizole and lorcaserin.

Cannabidiol modulates excitatory-inhibitory ratio to counter hippocampal hyperactivity

Cannabidiol (CBD), a non-euphoric component of cannabis, reduces seizures in multiple forms of pediatric epilepsies, but the mechanism(s) of anti-seizure action remain unclear. In one leading model, CBD acts at glutamatergic axon terminals, blocking the pro-excitatory actions of an endogenous membrane phospholipid, lysophosphatidylinositol (LPI), at the G-protein-coupled receptor GPR55. However, the impact of LPI-GPR55 signaling at inhibitory synapses and in epileptogenesis remains underexplored. We found that LPI transiently increased hippocampal CA3-CA1 excitatory presynaptic release probability and evoked synaptic strength in WT mice, while attenuating inhibitory postsynaptic strength by decreasing GABAARγ2 and gephyrin puncta. LPI effects at excitatory and inhibitory synapses were eliminated by CBD pre-treatment and absent after GPR55 deletion. Acute pentylenetrazole-induced seizures elevated GPR55 and LPI levels, and chronic lithium-pilocarpine-induced epileptogenesis potentiated LPI's pro-excitatory effects. We propose that CBD exerts potential anti-seizure effects by blocking LPI's synaptic effects and dampening hyperexcitability.

NETWORK ANALYSIS REVEALS A ROLE OF THE HIPPOCAMPUS IN ABSENCE SEIZURES: THE EFFECTS OF A CANNABINOID AGONIST

The role of the hippocampus (Hp) in absence epileptic networks and the effect of endocannabinoid system on this network remain enigmatic. Here, using adapted nonlinear Granger causality, we compared the differences in network strength in four intervals (baseline or interictal, preictal, ictal and postictal) in two hours before (Epoch 1) and six hours (epochs 2, 3 and 4) after the administration of three different doses of the endocannabinoid agonist WIN55,212-2 (WIN) or solvent. Local field potentials were recorded for eight hours in 23 WAG/Rij rats in the Frontal (FC), Parietal PC), Occipital Cortex (OC) and in the hippocampus (Hp). The four intervals were visually marked by an expert neurophysiologist and the strength of couplings between electrode pairs were calculated in both directions. Ictally, a strong decrease in coupling strength was found between Hp and FC, as well as a large increase bidirectionally between PC and FC and unidirectionally from FC and PC to OC, and from FC to Hp over all epochs. The highest dose of WIN increased the couplings strength from FC to Hp and from OC to PC during 4 and 2 hr respectively in all intervals, and decreased the FC to PC coupling strength postictally in epoch 2. A single rat showed generalized convulsive seizures after the highest dose: this rat shared not only coupling changes with the other rats in the same condition, but showed many more. WIN reduced SWD number in epoch 2 and 3, their mean duration increased in epochs 3 and 4. Conclusions:during SWDs FC and PC are strongly coupled and drive OC, while at the same time the influence of Hp to FC is diminished. The first is in agreement with the cortical focus theory, the latter demonstrates an involvement of the hippocampus in SWD occurrence and that ictally the hippocampal control of the cortico-thalamo-cortical system is lost. WIN causes dramatic network changes which have major consequences for the decrease of SWDs, the occurrence of convulsive seizures, and the normal cortico-cortical and cortico-hippocampal interactions.

Cannabinoid regulation of neurons in the dentate gyrus during epileptogenesis: Role of CB1R-associated proteins and downstream pathways

The hippocampal formation plays a central role in the development of temporal lobe epilepsy (TLE), a disease characterized by recurrent, unprovoked epileptic discharges. TLE is a neurologic disorder characterized by acute long-lasting seizures (i.e., abnormal electrical activity in the brain) or seizures that occur in close proximity without recovery, typically after a brain injury or status epilepticus. After status epilepticus, epileptogenic hyperexcitability develops gradually over the following months to years, resulting in the emergence of chronic, recurrent seizures. Acting as a filter or gate, the hippocampal dentate gyrus (DG) normally prevents excessive excitation from propagating through the hippocampus, and is considered a critical region in the progression of epileptogenesis in pathological conditions. Importantly, lipid-derived endogenous cannabinoids (endocannabinoids), which are produced on demand as retrograde messengers, are central regulators of neuronal activity in the DG circuit. In this review, we summarize recent findings concerning the role of the DG in controlling hyperexcitability and propose how DG regulation by cannabinoids (CBs) could provide avenues for therapeutic interventions. We also highlight possible pathways and manipulations that could be relevant for the control of hyperexcitation. The use of CB compounds to treat epilepsies is controversial, as anecdotal evidence is not always validated by clinical trials. Recent publications shed light on the importance of the DG as a region regulating incoming hippocampal excitability during epileptogenesis. We review recent findings concerning the modulation of the hippocampal DG circuitry by CBs and discuss putative underlying pathways. A better understanding of the mechanisms by which CBs exert their action during seizures may be useful to improve therapies.

Neuroimmunology of status epilepticus

Status epilepticus (SE) is a very heterogeneous clinical condition often refractory to available treatment options. Evidence in animal models shows that neuroinflammation arises in the brain during SE due to the activation of innate immune mechanisms in brain parenchyma cells. Intervention studies in animal models support the involvement of neuroinflammation in SE onset, duration, and severity, refractoriness to treatments, and long-term neurological consequences. Clinical evidence shows that neuroinflammation occurs in patients with SE of diverse etiologies likely representing a common phenomenon, thus broadening the involvement of the immune system beyond the infective and autoimmune etiologies. There is urgent need for novel therapies for refractory SE that rely upon a better understanding of the basic mechanisms underlying this clinical condition. Preclinical and clinical evidence encourage consideration of specific anti-inflammatory treatments for controlling SE and its consequences in patients.

A Complete Endocannabinoid Signaling System Modulates Synaptic Transmission between Human Induced Pluripotent Stem Cell-Derived Neurons

The endocannabinoid system (ECS) modulates synaptic function to regulate many aspects of neurophysiology. It adapts to environmental changes and is affected by disease. Thus, the ECS presents an important target for therapeutic development. Despite recent interest in cannabinoid-based treatments, few preclinical studies are conducted in human systems. Human induced pluripotent stem cells (hiPSCs) provide one possible solution to this issue. However, it is not known if these cells have a fully functional ECS. Here, we show that hiPSC-derived neuron/astrocyte cultures exhibit a complete ECS. Using Ca2+ imaging and a genetically encoded endocannabinoid sensor, we demonstrate that they not only respond to exogenously applied cannabinoids but also produce and metabolize endocannabinoids. Synaptically driven [Ca2+]i spiking activity was inhibited (EC50 = 48 ± 13 nM) by the efficacious agonist [R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrolol [1,2,3-de]-1,4-benzoxazin-yl]-(1-naphthalenyl)methanone mesylate] (Win 55,212-2) and by the endogenous ligand 2-arachidonoyl glycerol (2-AG; EC50 = 2.0 ± 0.6 µm). The effects of Win 55212-2 were blocked by a CB1 receptor-selective antagonist. Δ9-Tetrahydrocannabinol acted as a partial agonist, maximally inhibiting synaptic activity by 47 ± 14% (EC50 = 1.4 ± 1.9 µm). Carbachol stimulated 2-AG production in a manner that was independent of Ca2+ and blocked by selective inhibition of diacylglycerol lipase. 2-AG returned to basal levels via a process mediated by monoacylglycerol lipase as indicated by slowed recovery in cultures treated with 4-[Bis(1,3-benzodioxol-5-yl)hydroxymethyl]-1-piperidinecarboxylic acid 4-nitrophenyl ester (JZL 184). Win 55,212-2 markedly desensitized CB1 receptor function following a 1-day exposure, whereas desensitization was incomplete following 7-day treatment with JZL 184. This human cell culture model is well suited for functional analysis of the ECS and as a platform for drug development. SIGNIFICANCE STATEMENT: Despite known differences between the human response to cannabinoids and that of other species, an in vitro human model demonstrating a fully functional endocannabinoid system has not been described. Human induced pluripotent stem cells (hiPSCs) can be obtained from skin samples and then reprogrammed into neurons for use in basic research and drug screening. Here, we show that hiPSC-derived neuronal cultures exhibit a complete endocannabinoid system suitable for mechanistic studies and drug discovery.

Pharmacodynamic synergism contributes to the antiseizure action of cannabidiol and clobazam

The management of refractory epilepsy involves treatment with more than one antiseizure medication (ASM). Combination of ASMs with distinct mechanisms of action are hypothesized to improve overall treatment effectiveness. In clinical trials, concomitant use of cannabidiol (CBD) and clobazam (CLB) was associated with increased seizure reduction and bidirectional elevation in levels of their active metabolites, 7-hydroxy-cannabidiol (7-OH-CBD) and nor-clobazam (n-CLB). Using isobolographic analysis, we investigated whether CBD and CLB interacted pharmacodynamically. In the mouse maximal electroshock seizure (MES) test, brain tissue levels of CBD and CLB corresponding to seizure prevention in 50% of animals (brain Effective Exposure, bEE₅₀) were 7.9 μM and 1.6 μM, respectively. In the 6 Hz psychomotor seizure model, 7-OH-CBD displayed a 5-fold greater potency than CBD (b-EE₅₀, 8.7 μM vs 47.3 μM). Isobolographic analysis performed on combination of CBD/CLB at 1:1, 3:1, and 1:3 ratios based on equi-effective bEE₅₀ values revealed synergism at all doses with combination indices (CI) of 0.43, 0.62 and 0.75 respectively. These outcomes were independent of pharmacokinetic interaction between CBD and CLB. These findings identify pharmacodynamic synergism as an important factor underlying enhanced antiseizure effect during concomitant CBD and CLB use.

Isobolographic analysis of adjunct antiseizure activity of the FDA-approved cannabidiol with neurosteroids and benzodiazepines in adult refractory focal onset epilepsy

Epilepsy is a serious neurological disorder associated with recurrent and unpredictable seizures and extensive neuropsychiatric comorbidities. There is no cure for epilepsy, and over one third of epileptic patients have been diagnosed with drug-refractory epilepsy, indicating the critical need for novel antiseizure medications (ASMs). Cannabidiol (CBD) has been shown to decrease seizures in pediatric epilepsies, such as Dravet and Lennox-Gastaut syndromes; however, it has not been rigorously tested for adult seizures or in models of refractory focal epilepsy. Although the exact mechanism is unknown, it is likely to act in a way that is unique to certain GABA-A receptor-modulating drugs, such as neurosteroids and benzodiazepines. In this study, we sought to determine the adjunct antiseizure activity of a clinical CBD product in an adult 6-Hz model of focal refractory epilepsy. CBD was evaluated alone in both a dose-response and time-course manner and in an adjunct combination with two ASMs ganaxolone (neurosteroid) and midazolam (benzodiazepine) against 6-Hz-induced refractory focal onset, generalized seizures. In pharmacological studies, CBD produced dose-dependent protection against seizures (ED50, 53 mg/kg, i.p.) without any side effects. CBD significantly reduced both electrographic activity and behavioral ictal responses with no apparent sex differences. CBD was evaluated in an isobologram design in conjunction with ganaxolone or midazolam at three standard ratios (1:1, 1:3, 3:1). Isobolographic analysis shows the combination regimens of CBD + ganaxolone and CBD + midazolam exerted combination index of 0.313 and 0.164, indicating strong synergism for seizure protection, with little to no toxicity. Together, these results demonstrate the therapeutic potential of CBD monotherapy and as an adjunct therapy for adult focal refractory epilepsy in combination with GABAergic ASMs.

Therapeutic and clinical foundations of cannabidiol therapy for difficult-to-treat seizures in children and adults with refractory epilepsies

Novel and effective antiseizure medications are needed to treat refractory and rare forms of epilepsy. Cannabinoids, which are obtained from the cannabis plant, have a long history of medical use, including for neurologic conditions. In 2018, the US Food and Drug Administration approved the first phytocannabinoid, cannabidiol (CBD, Epidiolex), which is now indicated for severe seizures associated with three rare forms of developmental and epileptic encephalopathy: Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex. Compelling evidence supports the efficacy of CBD in experimental models and patients with epilepsy. In randomized clinical trials, highly-purified CBD has demonstrated efficacy with an acceptable safety profile in children and adults with difficult-to-treat seizures. Although the underlying antiseizure mechanisms of CBD in humans have not yet been elucidated, the identification of novel antiseizure targets of CBD preclinically indicates multimodal mechanisms that include non-cannabinoid pathways. In addition to antiseizure effects, CBD possesses strong anti-inflammatory and neuroprotective activities, which might contribute to protective effects in epilepsy and other conditions. This article provides a succinct overview of therapeutic approaches and clinical foundations of CBD, emphasizing the clinical utility of CBD for the treatment of seizures associated with refractory and rare epilepsies. CBD has shown to be a safe and effective antiseizure medicine, demonstrating a broad spectrum of efficacy across multiple seizure types, including those associated with severe epilepsies with childhood onset. Despite such promise, there are many perils with CBD that hampers its widespread use, including limited understanding of pharmacodynamics, limited exposure-response relationship, limited information for seizure freedom with continued use, complex pharmacokinetics with drug interactions, risk of adverse effects, and lack of expert therapeutic guidelines. These scientific issues need to be resolved by further investigations, which would decide the unique role of CBD in the management of refractory epilepsy.

Fenfluramine treatment is associated with improvement in everyday executive function in preschool-aged children (<5 years) with Dravet syndrome: A critical period for early neurodevelopment

OBJECTIVE

To evaluate whether fenfluramine (FFA) is associated with improvement in everyday executive function (EF)-self-regulation-in preschool-aged children with Dravet syndrome (DS).

METHODS

Children with DS received placebo or FFA in one of two phase III studies (first study: placebo, FFA 0.2 mg/kg/day, or FFA 0.7 mg/kg/day added to stiripentol-free standard-of-care regimens; second study: placebo or FFA 0.4 mg/kg/day added to stiripentol-inclusive regimens). Everyday EF was evaluated at baseline and Week 14-15 for children aged 2-4 years with parent ratings on the Behavior Rating Inventory of Executive Function®-Preschool (BRIEF®-P); raw scores were transformed to T-scores and summarized in Inhibitory Self-Control Index (ISCI), Flexibility Index (FI), Emergent Metacognition Index (EMI), and Global Executive Composite (GEC). Clinically meaningful improvement and worsening were defined using RCI ≥ 90% and RCI ≥ 80% certainty, respectively. The associations between placebo vs FFA combined (0.2, 0.4, and 0.7 mg/kg/day) or individual treatment groups and the likelihood of clinically meaningful change in BRIEF®-P indexes/composite T-scores were evaluated using Somers'd; pairwise comparisons were calculated by 2-sided Fisher's Exact tests (p ≤ 0.05) and Cramér's V.

RESULTS

Data were analyzed for 61 evaluable children of median age 3 years (placebo, n = 22; FFA 0.2 mg/kg/day, n = 15; 0.4 mg/kg/day [with stiripentol], n = 10; 0.7 mg/kg/day, n = 14 [total FFA, n = 39]). Elevated or problematic T-scores (T ≥ 65) were reported in 55% to 86% of patients at baseline for ISCI, EMI, and GEC, and in ∼33% for FI. Seventeen of the 61 children (28%) showed reliable, clinically meaningful improvement (RCI ≥ 90% certainty) in at least one BRIEF®-P index/composite, including a majority of the children in the FFA 0.7 mg/kg/day group (9/14, 64%). Only 53% of these children (9/17) also experienced clinically meaningful reduction (≥50%) in monthly convulsive seizure frequency, including 6/14 patients in the FFA 0.7 mg/kg/day group. Overall, there were positive associations between the four individual treatment groups and the likelihood of reliable, clinically meaningful improvement in all BRIEF®-P indexes/composite (ISCI, p = 0.001; FI, p = 0.005; EMI, p = 0.040; GEC, p = 0.002). The FFA 0.7 mg/kg/day group showed a greater likelihood of reliable, clinically meaningful improvement than placebo in ISCI (50% vs 5%; p = 0.003), FI (36% vs 0%; p = 0.005), and GEC (36% vs 0%; p = 0.005). For EMI, the FFA 0.7 mg/kg/day group showed a greater likelihood of reliable, clinically meaningful improvement than the FFA 0.2 mg/kg/day group (29% vs 0%; p = 0.040), but did not meet the significance threshold compared with placebo (29% vs 5%; p = 0.064). There were no significant associations between treatment and the likelihood of reliable, clinically meaningful worsening (p > 0.05).

SIGNIFICANCE

In this preschool-aged DS population with high baseline everyday EF impairment, FFA treatment for 14-15 weeks was associated with dose-dependent, clinically meaningful improvements in regulating behavior, emotion, cognition, and overall everyday EF. These clinically meaningful improvements in everyday EF were not entirely due to seizure frequency reduction, suggesting that FFA may have direct effects on everyday EF during the early formative years of neurodevelopment.

The Endocannabinoid System in Caenorhabditis elegans

The existence of a formal Endocannabinoid System in C. elegans has been questioned due to data showing the absence of typical cannabinoid receptors in the worm; however, the presence of a full metabolism for endocannabinoids, alternative ligands, and receptors for these agents and a considerable number of orthologous and homologous genes regulating physiological cannabinoid-like signals and responses - several of which are similar to those of mammals - demonstrates a well-structured and functional complex system in nematodes. In this review, we describe and compare similarities and differences between the Endocannabinoid System in mammals and nematodes, highlighting the basis for the integral study of this novel system in the worm.

Single cannabidiol administration affects anxiety-, obsessive compulsive-, object memory-, and attention-like behaviors in mice in a sex and concentration dependent manner

RATIONALE

The behavioral effects of cannabidiol (CBD) are understudied, but are important, given its therapeutic potential and widespread use as a natural supplement.

OBJECTIVE

The objective of this study was to test whether a single injection of CBD affected anxiety-like or attention-like behavior, or memory in wildtype mice or mice with reported trait anxiety due to a targeted gene-deletion in a voltage-dependent potassium channel, Kv1.3.

METHODS

Wildtype C57BL/6 J and Kv1.3-/- mice of both sexes were reared to adulthood and then administered an intraperitoneal injection of 10 or 20 mg/kg CBD. Mice were behaviorally-phenotyped using the marble-burying test, the light-dark box (LDB), short (1 h) and long-term (24 h) object memory test, the elevated-plus maze (EPM), and the object-based attention task in order to assess obsessive compulsive-, anxiety-, and attention-like behaviors, and memory.

RESULTS

We discovered that acute CBD treatment reduced marble burying in male, but not female mice. CBD was effective in lessening anxiety-like behaviors determined by the LDB test in both male and female wildtype mice, whereby the effective dose required to observe the effect in females was less. In Kv1.3-/- mice, CBD increased anxiety-like behaviors in the LDB in both sexes at the higher concentration of CBD and it similarly increased anxiety-like behavior in females in the EPM at the lower concentration of CBD. Long-term object memory was reduced in male wildtype mice at the lower concentration of CBD. Finally, ADHD- or attention-like behaviors were not altered by CBD in wildtype mice, but in Kv1.3-/- mice, females were observed to have a loss in attention while males demonstrated improved attention.

CONCLUSIONS

We conclude that administration of a single dose of CBD has immediate effects on mouse behavior that is dose, sex, and anxiety-state dependent - and that these behavioral outcomes are important to examine in parallel human trials.

Current Cannabidiol Safety: A Review

BACKGROUND

Marijuana, also known as cannabis, is the second most widely used illegal psychoactive substance smoked worldwide after tobacco, mainly due to the psychoactive effects induced by D-9-tetrahydrocannabinol (9-THC). Cannabidiol (CBD) is extracted from cannabis and may be used as an anti-inflammatory agent. Some patents on cannabidiol are discussed in this review. The cannabinoid is a non-psychoactive isomer of the more infamous tetrahydrocannabinol (THC); and is available in several administration modes, most known as CBD oil.

OBJECTIVES

This study aims to provide an enhanced review of cannabidiol properties used in treating inflammation. This review also emphasises the current safety profile of cannabidiol.

METHODS

Cannabis is also called Marijuana. It is the second most commonly used illegal psychoactive substance in the universe after tobacco. D-9-tetrahydrocannabinol (9-THC) present in cannabis produces psychoactive effects. Cannabidiol (CBD) extracted from cannabis is used for antiinflammatory purposes. Cannabis smoking causes various types of cancer, such as lung, tongue, and jaw. The current review took literature from Google Scholar, PubMed, and Google Patents. Many clinical investigations are included in this review.

RESULT

After analysing the literature on cannabis, it has been suggested that although cannabis is banned in some countries, it may be included in the treatment and mitigation of some diseases and symptoms like pain management, epilepsy, cancer, and anxiety disorder. Mild side effects were frequently observed in cannabis medications, which included infertility in females, liver damage, etc. Conclusion: Cannabis contains chemical compounds such as the cannabinoids delta-9- tetrahydrocannabinol (THC), a psychoactive substance, and non-psychoactive cannabidiol (CBD). Cannabidiol has been confirmed as an efficient treatment of epilepsy in several clinical trials, with one pure CBD product named Epidiolex. It is also used in treating anxiety and acne, as a pain reliever, and has anti-inflammatory properties.

Efficacy of the FDA-approved cannabidiol on the development and persistence of temporal lobe epilepsy and complex focal onset seizures

Presently there is no drug therapy for curing epilepsy. Despite many advancements in epilepsy research, nearly 30% of people with epilepsy remain refractory to current antiseizure medications (ASM). Cannabidiol (CBD) has recently been approved as an ASM for pediatric refractory seizures, but it has not been widely tested for adult epileptogenesis and focal onset seizures. In this study, we investigated the efficacy of the FDA-approved CBD in controlling epileptogenesis and complex focal onset seizures using the mouse kindling model of human temporal lobe epilepsy. We also tested combination regimens of CBD with other ASMs. The two primary outcome measures were disease modification and suppression of generalized seizures. In the epileptogenesis study, CBD had a striking effect in attenuating kindling development, with a dose-dependent decrease in behavioral and electrographic seizure activity. In the retention study, mice previously treated with CBD had significantly reduced overall seizure burden, suggesting disease modification. In a fully-kindled seizure study, CBD produced rapid and atypical U-shaped dose-dependent protection against generalized seizures (ED₅₀, 52 mg/kg, i.p.). In a time-course study, CBD showed a maximal protective effect within 1 h of injection, and it declined within 4 h with a biphasic response. In the combination study, CBD produced synergistic/ additive protection when given with midazolam and ganaxolone but not with tiagabine, indicating its strong potential as an adjunct ASM. Finally, the protective effects of CBD were not associated with motor and functional impairments. These preclinical findings demonstrate the potential of adjunct CBD for controlling adult complex focal onset seizure conditions.

Cannabidiol in canine epilepsy

The anticonvulsant effect of cannabidiol (CBD), which has been confirmed by findings from animal models and human trials, has attracted the interest of veterinary practitioners and dog owners. Moreover, social media and public pressure has sparked a renewed awareness of cannabinoids, which have been used for epilepsy since ancient times. Unfortunately, at this moment veterinarians and veterinary neurologists have difficulty prescribing cannabinoids because of the paucity of sound scientific studies. Pharmacokinetic studies in dogs have demonstrated a low oral bioavailability of CBD and a high first-pass effect through the liver. Administering CBD in oil-based formulations and/or with food has been shown to enhance the bioavailability in dogs, rats and humans. Tolerability studies in healthy dogs and dogs with epilepsy have demonstrated that CBD was safe and well tolerated with only mild to moderate adverse effects. In this context, it should be noted that the quality of available CBD varies widely, underscoring the importance of pharmaceutical quality and its control. One clinical trial in dogs with drug-resistant idiopathic epilepsy failed to confirm a difference in response rates between the CBD group and the placebo group, while in another cross-over trial a ≥ 50 % reduction in epileptic seizure frequency was found in six of 14 dogs in the treatment phase, a reduction that was not observed during the placebo phase. Based on the current state of knowledge it is not possible to provide clear-cut recommendations for the use of CBD in canine epilepsy. Randomized controlled canine trials with large sample sizes are needed to determine the range of therapeutic plasma concentrations, develop evidence-based dosing regimens, determine the efficacy of cannabidiol in drug-refractory epilepsy, and explore potential associations between treatment effects and different etiologies, epilepsy types, and drug combinations.

The impact of phyto- and endo-cannabinoids on central nervous system diseases：A review

Background and aim

Cannabis sativa L. is a medicinal plant with a long history. Phyto-cannabinoids are a class of compounds from C. sativa L. with varieties of structures. Endocannabinoids exist in the human body. This article provides an overview of natural cannabinoids (phyto-cannabinoids and endocannabinoids) with an emphasis on their pharmacology activities.

Experimental procedure

The keywords "Cannabis sativa L″, "cannabinoids", and "central nervous system (CNS) diseases" were used for searching and collecting pieces of literature from PubMed, ScienceDirect, Web of Science, and Google Scholar. The data were extracted and analyzed to explore the effects of cannabinoids on CNS diseases.

Result and conclusion

In this paper, schematic diagrams are used to intuitively show the phyto-cannabinoids skeletons' mutual conversion and pharmacological activities, with special emphasis on their relevant pharmacological activities on central nervous system (CNS) diseases. It was found that the endocannabinoid system and microglia play a crucial role in the treatment of CNS diseases. In the past few years, pharmacological studies focused on Δ⁹-THC, CBD, and the endocannabinoids system. It is expected to encourage new studies on a more deep exploration of other types of cannabinoids and the mechanism of their pharmacological activities in the future.

Cannabidiol Impairs Brain Mitochondrial Metabolism and Neuronal Integrity

Background: The mechanisms underlying the clinical effects of CBD remain poorly understood. Given the increasing evidence for CBD's effects on mitochondria, we sought to examine in more detail whether CBD impacts mitochondrial function and neuronal integrity. Methods: We utilized BE(2)-M17 neuroblastoma cells or acutely isolated brain mitochondria from rodents using a Seahorse extracellular flux analyzer and a fluorescent spectrofluorophotometer assay. Mitochondrial ion channel activity and hippocampal long-term potentiation were measured using standard cellular electrophysiological methods. Spatial learning/memory function was evaluated using the Morris water maze task. Plasma concentrations of CBD were assessed with liquid chromatography-mass spectrometry, and cellular viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction neuronal injury assay. Results: At low micromolar concentrations, CBD reduced mitochondrial respiration, the threshold for mitochondrial permeability transition, and calcium uptake, blocked a novel mitochondrial chloride channel, and reduced the viability of hippocampal cells. These effects were paralleled by in vitro and in vivo learning/memory deficits. We further found that these effects were independent of cannabinoid receptor 1 and mitochondrial G-protein-coupled receptor 55. Conclusion: Our results provide evidence for concentration- and dose-dependent toxicological effects of CBD, findings that may bear potential relevance to clinical populations.

Pharmacological perspectives and mechanisms involved in epileptogenesis

Background

Epileptogenesis can be defined as the process by which a previously healthy brain develops a tendency toward recurrent electrical activity, occurring in three phases: first as an initial trigger (such as stroke, infections, and traumatic brain injury); followed by the latency period and the onset of spontaneous and recurrent seizures which characterizes epilepsy.

Main body

The mechanisms that may be involved in epileptogenesis are inflammation, neurogenesis, migration of neurons to different regions of the brain, neural reorganization, and neuroplasticity.In recent years, experimental studies have enabled the discovery of several mechanisms involved in the process of epileptogenesis, mainly neuroinflammation, that involves the activation of glial cells and an increase in specific inflammatory mediators. The lack of an experimental animal model protocol for epileptogenic compounds contributes to the difficulty in understanding disease development and the creation of new drugs.

Conclusion

To solve these difficulties, a new approach is needed in the development of new AEDs that focus on the process of epileptogenesis and the consolidation of animal models for studies of antiepileptogenic compounds, aiming to reach the clinical phases of the study. Some examples of these compounds are rapamycin, which inhibits mTOR signaling, and losartan, that potentiates the antiepileptogenic effect of some AEDs. Based on this, this review discusses the main mechanisms involved in epileptogenesis, as well as its pharmacological approach.

Behavioral and Molecular Responses to Exogenous Cannabinoids During Pentylenetetrazol-Induced Convulsions in Male and Female Rats

Epilepsy is a disabling, chronic brain disease,affecting ~1% of the World’s population, characterized by recurrent seizures (sudden, uncontrolled brain activity), which may manifest with motor symptoms (e.g., convulsions) or non-motor symptoms. Temporal lobe epilepsies (TLE) compromising the hippocampus are the most common form of focal epilepsies. Resistance in ~1/3 of epileptic patients to the first line of treatment, i.e., antiepileptic drugs (AEDs), has been an important motivation to seek alternative treatments. Among these, the plant Cannabis sativa (commonly known as marihuana) or compounds extracted from it (cannabinoids) have gained widespread popularity. Moreover, sex differences have been proposed in epilepsy syndromes and in cannabinoid action. In the hippocampus, cannabinoids interact with the CB1R receptor whose membrane levels are regulated by β-Arrestin2, a protein that promotes its endocytosis and causes its downregulation. In this article, we evaluate the modulatory role of WIN 55,212-2 (WIN), a synthetic exogenous cannabinoid on behavioral convulsions and on the levels of CB1R and β-Arrestin2 in female and male adolescent rats after a single injection of the proconvulsant pentylenetetrazol (PTZ). As epilepsies can have a considerable impact on synaptic proteins that regulate neuronal toxicity, plasticity, and cognition, we also measured the levels of key proteins markers of excitatory synapses, in order to examine whether exogenous cannabinoids may prevent such pathologic changes after acute seizures. We found that the exogenous administration of WIN prevented convulsions of medium severity in females and males and increased the levels of phosphorylated CaMKII in the hippocampus. Furthermore, we observed a higher degree of colocalization between CB1R and β-Arrestin2 in the granule cell layer.

Anticonvulsant Action and Long-Term Effects of Chronic Cannabidiol Treatment in the Rat Pentylenetetrazole-Kindling Model of Epilepsy

Cannabidiol (CBD) showed anticonvulsant action in several preclinical models and is currently approved by regulatory agencies to treat childhood epilepsy syndromes. However, CBD treatment has limited benefits, and its long-term effects on cognition are not fully understood yet. This study aimed to examine the impact of long-term CBD treatment in the pentylenetetrazole (PTZ)-kindling model of epilepsy. Adult male Wistar rats (N = 24) received PTZ (35 mg/kg intraperitoneally) every other day until two consecutive generalized seizures occurred. CBD (60 mg/kg body weight) was administered daily by the oral route until the kindled state was achieved (n = 12). To confirm that the formulation and administration techniques were not of concern, liquid chromatography–mass spectrometry was performed to test the brain penetration of the CBD formula. As a result of CBD treatment, a lower mortality rate and significantly prolonged generalized seizure latency (925.3 ± 120.0 vs. 550.1 ± 69.62 s) were observed, while the frequency and duration of generalized seizures were not influenced. The CBD-treated group showed a significant decrease in vertical exploration in the open field test and a significant decrease in the discrimination index in the novel object recognition (NOR) test (−0.01 ± 0.17 vs. 0.57 ± 0.15, p = 0.04). The observed behavioral characteristics may be connected to the decreased thickness of the stratum pyramidale or the decreased astrogliosis observed in the hippocampus. In conclusion, CBD treatment did not prevent kindling, nor did it affect seizure frequency or duration. However, it did increase the latency to the first seizure and decreased the prolonged status epilepticus-related mortality in PTZ-kindled rats. The cognitive impairment observed in the NOR test may be related to the high dose used in this study, which may warrant further investigation.

Adjunctive Transdermal Cannabidiol for Adults With Focal Epilepsy: A Randomized Clinical Trial

Importance

Cannabidiol has shown efficacy in randomized clinical trials for drug-resistant epilepsy in specific syndromes that predominantly affect children. However, high-level evidence for the efficacy and safety of cannabidiol in the most common form of drug-resistant epilepsy in adults, focal epilepsy, is lacking.

Objective

To investigate the efficacy, safety, and tolerability of transdermally administered cannabidiol in adults with drug-resistant focal epilepsy.

Design, Setting, and Participants

A randomized, double-blind, placebo-controlled, multicenter clinical trial at 14 epilepsy trial centers in Australia and New Zealand. Participants were adults with drug-resistant focal epilepsy receiving a stable regimen of up to 3 antiseizure medications. Data were analyzed from July 2017 to November 2018.

Interventions

Eligible participants were randomized (1:1:1) to 195-mg or 390-mg transdermal cannabidiol or placebo twice daily for 12 weeks, after which they could enroll in an open-label extension study for up to 2 years.

Main Outcomes and Measures

Seizure frequency was self-reported using a daily diary. The primary efficacy end point was the least squares mean difference in the log-transformed total seizure frequency per 28-day period, adjusted to a common baseline log seizure rate, during the 12-week treatment period.

Results

A total of 188 patients (45% male [85 patients] and 54.8% female [103 patients]) with a mean (SD) age of 39.2 (12.78) years were randomized, treated, and analyzed (195-mg cannabidiol, 63 participants; 390-mg cannabidiol, 62 participants; placebo, 63 participants). At week 12 of the double-blind period, there was no difference in seizure frequency between placebo (mean [SD] 2.49 [1.31] seizures per 28 days) and 195-mg cannabidiol (mean [SD] 2.51 [1.15] seizures per 28 days; least squares mean difference, 0.014; 95% CI, -0.175 to 0.203; P = .89) or 390-mg cannabidiol (mean [SD] 2.59 [1.12] seizures per 28 days; least squares mean difference, 0.096; 95% CI, -0.093 to 0.285; P = .32). By month 6 of the open-label extension, 115 patients (60.8%) achieved a seizure reduction of at least 50%. Treatment-emergent adverse events occurred in 50.4% (63 of 125 participants) of the cannabidiol group vs 41.3% (26 of 63 participants) in the placebo group, with a treatment difference of 9.1% (95% CI, -6.0% to 23.6%), and occurred at similar rates in the cannabidiol groups. Few participants discontinued (7% [14 of 188 participants]), and most (98% [171 of 174 participants]) continued into the open-label extension.

Conclusions and Relevance

Both doses of transdermal cannabidiol were well tolerated and safe. No significant difference in efficacy was observed between cannabidiol and placebo during the double-blind treatment period. The open-label extension demonstrated the long-term safety, tolerability, and acceptability of transdermal cannabidiol delivery.

Trial Registration

ACTRN12616000510448 (double-blind); ACTRN12616001455459 (open-label).

A Review on the Recent Advancements on Therapeutic Effects of Ions in the Physiological Environments

This review focuses on the therapeutic effects of ions when released in physiological environments. Recent studies have shown that metallic ions like Ag+, Sr2+, Mg2+, Mn2+, Cu2+, Ca2+, P+5, etc., have shown promising results in drug delivery systems and regenerative medicine. These metallic ions can be loaded in nanoparticles, mesoporous bioactive glass nanoparticles (MBGNs), hydroxyapatite (HA), calcium phosphates, polymeric coatings, and salt solutions. The metallic ions can exhibit different functions in the physiological environment such as antibacterial, antiviral, anticancer, bioactive, biocompatible, and angiogenic effects. Furthermore, the metals/metalloid ions can be loaded into scaffolds to improve osteoblast proliferation, differentiation, bone development, fibroblast growth, and improved wound healing efficacy. Moreover, different ions possess different therapeutic limits. Therefore, further mechanisms need to be developed for the highly controlled and sustained release of these ions. This review paper summarizes the recent progress in the use of metallic/metalloid ions in regenerative medicine and encourages further study of ions as a solution to cure diseases.

Analysing an allelic series of rare missense variants of CACNA1I in a Swedish schizophrenia cohort

CACNA1I is implicated in the susceptibility to schizophrenia by large-scale genetic association studies of single nucleotide polymorphisms. However, the channelopathy of CACNA1I in schizophrenia is unknown. CACNA1I encodes CaV3.3, a neuronal voltage-gated calcium channel that underlies a subtype of T-type current that is important for neuronal excitability in the thalamic reticular nucleus and other regions of the brain. Here, we present an extensive functional characterization of 57 naturally occurring rare and common missense variants of CACNA1I derived from a Swedish schizophrenia cohort of more than 10 000 individuals. Our analysis of this allelic series of coding CACNA1I variants revealed that reduced CaV3.3 channel current density was the dominant phenotype associated with rare CACNA1I coding alleles derived from control subjects, whereas rare CACNA1I alleles from schizophrenia patients encoded CaV3.3 channels with altered responses to voltages. CACNA1I variants associated with altered current density primarily impact the ionic channel pore and those associated with altered responses to voltage impact the voltage-sensing domain. CaV3.3 variants associated with altered voltage dependence of the CaV3.3 channel and those associated with peak current density deficits were significantly segregated across affected and unaffected groups (Fisher's exact test, P = 0.034). Our results, together with recent data from the SCHEMA (Schizophrenia Exome Sequencing Meta-Analysis) cohort, suggest that reduced CaV3.3 function may protect against schizophrenia risk in rare cases. We subsequently modelled the effect of the biophysical properties of CaV3.3 channel variants on thalamic reticular nucleus excitability and found that compared with common variants, ultrarare CaV3.3-coding variants derived from control subjects significantly decreased thalamic reticular nucleus excitability (P = 0.011). When all rare variants were analysed, there was a non-significant trend between variants that reduced thalamic reticular nucleus excitability and variants that either had no effect or increased thalamic reticular nucleus excitability across disease status. Taken together, the results of our functional analysis of an allelic series of >50 CACNA1I variants in a schizophrenia cohort reveal that loss of function of CaV3.3 is a molecular phenotype associated with reduced disease risk burden, and our approach may serve as a template strategy for channelopathies in polygenic disorders.

Neuroplastic alterations in cannabinoid receptors type 1 (CB1) in animal models of epileptic seizures

Currently, there is an urgent need to better comprehend neuroplastic alterations in cannabinoid receptors type 1 (CB1) and to understand the biological meaning of these alterations in epileptic disorders. The present study reviewed neuroplastic changes in CB1 distribution, expression, and functionality in animal models of epileptic seizures. Neuroplastic alterations in CB1 were consistently observed in chemical, genetic, electrical, and febrile seizure models. Most studies assessed changes in hippocampal and cortical CB1, while thalamic, hypothalamic, and brainstem nuclei were rarely investigated. Additionally, the relationship between CB1 alteration and the control of brain excitability through modulation of specific neuronal networks, such as striatonigral, nigrotectal and thalamocortical pathways, and inhibitory projections to hippocampal pyramidal neurons, were all presented and discussed in the present review. Neuroplastic alterations in CB1 detected in animal models of epilepsy may reflect two different scenarios: (1) endogenous adaptations aimed to control neuronal hyperexcitability in epilepsy or (2) pathological alterations that facilitate neuronal hyperexcitability. Additionally, a better comprehension of neuroplastic and functional alterations in CB1 can improve pharmacological therapies for epilepsies and their comorbidities.

Cannabidiol and epilepsy in Brazil: a current review

BACKGROUND

Cannabidiol (CBD) has become a promising therapeutic option in the treatment of epilepsy. Recent studies provide robust evidence that CBD is effective and safe. Limitations in current knowledge and regulatory issues still limit CBD use. CBD use regarding epilepsy types still lacks clear guidelines.

OBJECTIVE

To critically review the main current pharmacological features and clinical issues regarding CBD use in epilepsy, to provide current regulatory background regarding CBD use in Brazil, and to suggest a practical CBD therapeutic guide in Brazil.

METHODS

Non-systematic literature review (up to February 2022) of current concepts of CBD and epilepsy, including the authors' personal experience.

RESULTS

Five pivotal trials have led to CBD approval as an adjunctive treatment for Dravet and Lennox-Gastaut syndromes, and for the tuberous sclerosis complex. Efficacy of CBD in other drug-resistant epilepsies remains not completely understood. CBD adverse event profile and drug interactions are better understood. CBD is well tolerated. In Brazil, CBD is not classified as a medication, but as a product subject to a distinct regulatory legislation. CBD is still not offered by the National Brazilian health system, but can be purchased in authorized pharmacies or imported under prescription and signed informed consent.

CONCLUSION

CBD is a recognized novel treatment for epilepsy. Future well-designed studies and public health strategies are needed to offer widespread access to CBD, and to improve the quality of life of people living with epilepsy in Brazil.

Partial protective effects of cannabidiol against PTZ-induced acute seizures in female rats during the proestrus-estrus transition

Approximately 70% of women with epilepsy experience additional challenges in seizure exacerbation due to hormonal changes, particularly during fluctuations of estrogen-progesterone levels in the menstrual cycle, which is known as catamenial epilepsy. In animal models of epilepsy, a sustained increase in seizure frequency has been observed in female rats during the proestrus-estrus transition when estrogen levels are high and progesterone levels are low resembling catamenial epilepsy. Cannabidiol (CBD) has been proposed to have anticonvulsant and anti-inflammatory effects, able to decrease seizure duration and increase seizure threshold in rats with epilepsy. However, most studies have used males to investigate the pharmacological effects of CBD on seizures, and the neuroprotective effects of CBD against seizures exacerbated by hormonal fluctuations in females are still little explored. Given this scenario, the aim of the present study was to investigate whether CBD would protect against acute seizures induced by pentylenetetrazole (PTZ) in female rats during a pro-convulsant hormonal phase. Therefore, CBD (50 mg/kg) or saline was administered during the proestrus-estrus transition phase, 1 h prior to induction of seizures with PTZ (60 mg/kg), and the following parameters were recorded: duration, latency to first seizure, as well as percentage of convulsing animals (incidence), mortality, and severity of seizures. Brains were processed for immunohistochemistry for microglial cells (Iba-1), and blood was collected for the analysis of cytokines (IL-1β, IL-6, IL-10, and TNF-α). Cannabidiol pre-treated rats showed a significant reduction in duration and severity of seizures, and IL-1β levels, although the latency, incidence of seizures, and mortality rate remained unchanged as well the quantification of microglia in the selected areas. Therefore, acute administration of CBD in a single dose prior to seizure induction showed a partial neuroprotective effect against seizure severity and inflammation, suggesting that female rats in the proconvulsant phase of proestrus-estrus have a low seizure threshold and are more resistant to the anticonvulsant effects of CBD. It appears that other doses or administration windows of CBD may be required to achieve a full protective effect against seizures, suggesting that CBD could be used as an adjunctive therapy during fluctuations of estrogen-progesterone levels. In this sense, considering the hormonal fluctuation as a seizure-potentiating factor, our study contributes to understand the anticonvulsant activity of CBD in females in a pro-convulsant hormonal phase, similar to catamenial seizures in humans.

The endocannabinoid system in zebrafish and its potential to study the effects of Cannabis in humans

Zebrafish is considered an unprecedented animal model in drug discovery. A review of the literature presents highlights and elucidates the biological effects of chemical components found in Cannabis sativa. Particular attention is paid to endocannabinoid system (eCB) and its main receptors (CB1 and CB2). The zebrafish model is a promising one for the study of cannabinoids because of the many similarities to the human system. Despite the recent advances on the eCB system, there is still the need to elucidate some of the interactions and, thus, the zebrafish model can be used for that purpose as it respects the 3Rs concept and reduced time and costs. In view of the relevance of cannabinoids in the treatment and prevention of diseases, as well as the importance of the zebrafish animal model in elucidating the biological effects of new drugs, the aim of this study was to bring to light information on the use of the zebrafish animal model in testing C. sativa-based medicines.

Cannabidiol activates neuronal Kv7 channels

Cannabidiol (CBD), a chemical found in the Cannabis sativa plant, is a clinically effective antiepileptic drug whose mechanism of action is unknown. Using a fluorescence-based thallium flux assay, we performed a large-scale screen and found enhancement of flux through heterologously expressed human Kv7.2/7.3 channels by CBD. Patch-clamp recordings showed that CBD acts at submicromolar concentrations to shift the voltage dependence of Kv7.2/7.3 channels in the hyperpolarizing direction, producing a dramatic enhancement of current at voltages near –50 mV. CBD enhanced native M-current in mouse superior cervical ganglion starting at concentrations of 30 nM and also enhanced M-current in rat hippocampal neurons. The potent enhancement of Kv2/7.3 channels by CBD may contribute to its effectiveness as an antiepileptic drug by reducing neuronal hyperexcitability.

Modulation of Recombinant Human T-Type Calcium Channels by Δ9-Tetrahydrocannabinolic Acid In Vitro

Introduction: Low voltage-activated T-type calcium channels (T-type I_Ca), Ca_V3.1, Ca_V3.2, and Ca_V3.3, are opened by small depolarizations from the resting membrane potential in many cells and have been associated with neurological disorders, including absence epilepsy and pain. Δ⁹-tetrahydrocannabinol (THC) is the principal psychoactive compound in Cannabis and also directly modulates T-type I_Ca; however, there is no information about functional activity of most phytocannabinoids on T-type calcium channels, including Δ⁹-tetrahydrocannabinolic acid (THCA), the natural nonpsychoactive precursor of THC. The aim of this work was to characterize THCA effects on T-type calcium channels. Materials and Methods: We used HEK293 Flp-In-TREx cells stably expressing Ca_V3.1, 3.2, or 3.3. Whole-cell patch clamp recordings were made to investigate cannabinoid modulation of I_Ca. Results: THCA and THC inhibited the peak current amplitude Ca_V3.1 with pEC₅₀s of 6.0±0.7 and 5.6±0.4, respectively. THC (1 μM) or THC produced a significant negative shift in half activation and inactivation of Ca_V3.1, and both drugs prolonged Ca_V3.1 deactivation kinetics. THCA (10 μM) inhibited Ca_V3.2 by 53%±4%, and both THCA and THC produced a substantial negative shift in the voltage for half inactivation and modest negative shift in half activation of Ca_V3.2. THC prolonged the deactivation time of Ca_V3.2, while THCA did not. THCA inhibited the peak current of Ca_V3.3 by 43%±2% (10 μM) but did not notably affect Ca_V3.3 channel activation or inactivation; however, THC caused significant hyperpolarizing shift in Ca_V3.3 steady-state inactivation. Discussion: THCA modulated T-type I_Ca currents in vitro, with significant modulation of kinetics and voltage dependence at low μM concentrations. This study suggests that THCA may have potential for therapeutic use in pain and epilepsy through T-type calcium channel modulation without the unwanted psychoactive effects associated with THC.

The Role of the Possible Receptors and Intracellular Pathways in Protective Effect of Exogenous Anandamide in Kindling Model of Epilepsy

In this research, the involvement of CB1 and TRPV1 receptors in the possible protective effects of anandamide were investigated in the kindling model of epilepsy. The basolateral amygdala of the rat brain was chosen to put stimulating electrodes. Semi-rapid kindling was induced by a repetitive sub-threshold stimulation for 5-9 consecutive days. There were seven groups, six of which were kindled and used for drug testing by intracerebroventricular (i.c.v.) microinjection. (i) Sham, (ii) control group received vehicles, (iii) anandamide (AEA; 100 ng/rat), (iv) capsazepine (TRPV1 antagonist; 100 ng/rat), (v) AM251 (CB1 antagonist; 100 ng/rat), (vi) AM251 + anandamide, and (vii) capsazepine + anandamide. The after-discharge duration, seizure duration, and stage five duration were measured in rats. Moreover, the expressions of the extracellular signal-regulated kinase (ERK) and the cAMP responsive element binding (CREB) proteins in the hippocampus were also studied. The anandamide-treated group showed a significant decrease in seizure scores, while no change was shown in seizure scores in the capsazepine- and AM251-treated groups compared with the control group. Co-administrations of either capsazepine + AEA or AM251 + AEA attenuated the protective effect of AEA against seizure. Furthermore, the group received AEA showed a decrease in the expressions of CREB and p-CREB possibly through the activation of the CB1 and TRPV1 receptors. Activation of CB1 and TRPV1 receptors might be involved in AEA anticonvulsant effect in kindling model of epilepsy. This effect could be due to suppression of CREB phosphorylation in hippocampal neurons.

Epilepsy and cannabis: so near, yet so far

Following media attention on children with refractory epilepsies reportedly deriving benefit from cannabis-based medicinal products (CBMPs), the UK government changed the law in 2018 so that CBMPs could be legally prescribed. Subsequently, a pure cannabidiol (CBD) product has been licensed for two epilepsy syndromes. However, despite pressure from campaign groups and allied politicians, almost no children have received unlicensed CBMPs under the UK NHS. This review explores the science behind CBMPs in paediatric epilepsies and highlights the areas that warrant further research. It identifies a lack of level I evidence for efficacy and safety as, currently, the major obstacle to prescribing. Unlicensed medicines are often used in paediatrics but almost all are used 'off-label', with supporting evidence of efficacy and safety derived either from other age-groups or from disease conditions. CBMPs, except for pure CBD, are unique in that they are currently both unlicensed and fall outside the 'off-label' category. The review acknowledges the treatment gap in refractory epilepsies and the potential use of CBMPs. However, it argues against exceptionally circumventing the usual standard of evidence required by regulatory prescribing authorities and warns against allowing vulnerable children to become the 'trojan horse' for deregulation of the commercial cannabis market.

Considerations for Cannabinoids in Perioperative Care by Anesthesiologists

Increased usage of recreational and medically indicated cannabinoid compounds has been an undeniable reality for anesthesiologists in recent years. These compounds’ complicated pharmacology, composition, and biological effects result in challenging issues for anesthesiologists during different phases of perioperative care. Here, we review the existing formulation of cannabinoids and their biological activity to put them into the context of the anesthesia plan execution. Perioperative considerations should include a way to gauge the patient’s intake of cannabinoids, the ability to gain consent properly, and vigilance to the increased risk of pulmonary and airway problems. Intraoperative management in individuals with cannabinoid use is complicated by the effects cannabinoids have on general anesthetics and depth of anesthesia monitoring while simultaneously increasing the potential occurrence of intraoperative hemodynamic instability. Postoperative planning should involve higher vigilance to the risk of postoperative strokes and acute coronary syndromes. However, most of the data are not up to date, rending definite conclusions on the importance of perioperative cannabinoid intake on anesthesia management difficult.

The type 1 cannabinoid receptor positive allosteric modulators GAT591 and GAT593 reduce spike-and-wave discharges in Genetic Absence Epilepsy Rats from Strasbourg

Childhood absence epilepsy (CAE) is a non-convulsive seizure disorder primarily in children characterized by absence seizures. Absence seizures consist of 2.5–5 Hz spike-and-wave discharges (SWDs) detectable using electroencephalography (EEG). Current drug treatments are only partially effective and adverse side effects have spurred research into alternative treatment approaches. Recent research shows that positive allosteric modulation of the type-1 cannabinoid receptor (CB1R) reduces the frequency and duration of SWDs in Genetic Absence Epilepsy Rats from Strasbourg (GAERS), a model that recapitulates the SWDs in CAE. Here, we tested additional CB1R ago-PAMs, GAT591 and GAT593, for their potential in alleviating SWD activity in GAERS. In vitro experiments confirm that GAT591 and GAT593 exhibit increased potency and selectivity in cell cultures and behave as CB1R allosteric agonists and PAMs. To assess drug effects on SWDs, bilateral electrodes were surgically implanted in the somatosensory cortices of male GAERS and EEGs recorded for 4 h following systemic administration of GAT591 or GAT593 (1.0, 3.0 and 10.0 mg/kg). Both GAT591 and GAT593 dose-dependently reduced total SWD duration during the recording period. The greatest effect on SWD activity was observed at 10.0 mg/kg doses, with GAT591 and GAT593 reducing seizure duration by 36% and 34% respectively. Taken together, these results support the continued investigation of CB1R PAMs as a potential therapeutic to alleviate SWDs in absence epilepsy.

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Positive allosteric modulators (PAMs) of cannabinoid type 1 receptors may help treat absence epilepsy.

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Two ago-PAMs for CB1Rs were assessed using in vitro and in vivo assays.

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The increased efficacy of the CB1R-PAMs GAT591 and GAT593 was confirmed in vitro.

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Systemic injection of either compound reduced spike-and-wave discharges in a rat genetic model of absence epilepsy.

Commonalities for comorbidity: Overlapping features of the endocannabinoid system in depression and epilepsy

A wealth of clinical and pre-clinical data supports a bidirectional comorbidity between depression and epilepsy. This suggests commonalities in underlying mechanisms that may serve as targets for more effective treatment strategies. Unfortunately, many patients with this comorbidity are highly refractory to current treatment strategies, while others experience a worsening of one arm of the comorbidity when treating the other arm. This highlights the need for novel pharmaceutical targets that may provide safe and effective relief for both depression and epilepsy symptoms. The endocannabinoid system (ECS) of the brain has become an area of intense interest for possible roles in depression and epilepsy. Several existing literature reviews have provided in-depth analysis of the involvement of various aspects of the ECS in depression or epilepsy separately, while others have addressed the effectiveness of different treatment strategies targeting the ECS in either condition individually. However, there is not currently a review that considers the ECS when both conditions are comorbid. This mini-review will address areas of common overlap between the ECS in depression and in epilepsy, such as commonalities in endocannabinoids themselves, their receptors, and degradative enzymes. These areas of overlap will be discussed alongside their implications for treatment of this challenging comorbidity.

The Endocannabinoid System in Glial Cells and Their Profitable Interactions to Treat Epilepsy: Evidence from Animal Models

Epilepsy is one of the most common neurological conditions. Yearly, five million people are diagnosed with epileptic-related disorders. The neuroprotective and therapeutic effect of (endo)cannabinoid compounds has been extensively investigated in several models of epilepsy. Therefore, the study of specific cell-type-dependent mechanisms underlying cannabinoid effects is crucial to understanding epileptic disorders. It is estimated that about 100 billion neurons and a roughly equal number of glial cells co-exist in the human brain. The glial population is in charge of neuronal viability, and therefore, their participation in brain pathophysiology is crucial. Furthermore, glial malfunctioning occurs in a wide range of neurological disorders. However, little is known about the impact of the endocannabinoid system (ECS) regulation over glial cells, even less in pathological conditions such as epilepsy. In this review, we aim to compile the existing knowledge on the role of the ECS in different cell types, with a particular emphasis on glial cells and their impact on epilepsy. Thus, we propose that glial cells could be a novel target for cannabinoid agents for treating the etiology of epilepsy and managing seizure-like disorders.

Klotho ameliorated cognitive deficits in a temporal lobe epilepsy rat model by inhibiting ferroptosis

Cognitive deficits are among the most common comorbidities of temporal lobe epilepsy (TLE). Ferroptosis associated with the accumulation of iron overload-dependent lipid peroxidation produces significant cognitive deficits in TLE. The anti-aging protein, klotho, has been shown to exert neuroprotective effects while enhancing cognition in neurodegenerative disorders. However, the role of klotho in TLE progression has not been established. In this study, we evaluated the effects and underlying mechanisms of klotho in a rat model of TLE induced by lithium-chloride and pilocarpine (LiCl-Pilo). The expression of klotho was found to be inhibited in the hippocampus following LiCl-Pilo induced TLE in rats. An adeno-virus (AAV), which mediated klotho overexpression (AAV-KL) was injected into the bilateral hippocampus of the rat models. After 3 weeks, rats were treated through intraperitoneal injections of LiCl-Pilo. After 9 weeks, AAV-KL was found to have significantly induced klotho overexpression in the hippocampus, effectively ameliorated cognitive deficits and exerted neuroprotective effects in LiCl-Pilo induced TLE rat models. Klotho significantly prevented ferroptosis and iron overload. Meanwhile, klotho regulated the expressions of divalent metal transporter 1 (DMT 1) and ferroportin (FPN) that were associated with iron accumulation in the hippocampus. Furthermore, klotho significantly elevated glutathione peroxidase-4 (GPX-4) and glutathione (GSH) levels while suppressed reactive oxygen species (ROS) levels. In conclusion, klotho ameliorated cognitive deficits and exerted neuroprotective effects by inhibiting ferroptosis in LiCl-Pilo induced TLE rat models.

The perceived effects of cannabis products in the management of seizures in CDKL5 Deficiency Disorder

INTRODUCTION

CDKL5 Deficiency Disorder (CDD) is a severe treatment-resistant form of early-onset epilepsy. Current treatment options are often ineffective and associated with adverse effects, forcing families to seek alternative therapies for their children including products derived from cannabis. Reportsof miraculous cures and a public preferencefor 'natural' therapies have resulted in considerable public interest, and so this study aimed to characterize the use of cannabis in these individuals, as well as compare caregiver perceptions of efficacy and safety to objective evidence of seizure control and number of antiepileptic drugs used.

METHODS

Families from the International CDKL5 Disorder Database were invited to complete questionnaires which included data relating to their child's current and past treatments, including use of any cannabis-derived preparations. Perceived effects on seizure control, as well as additional benefits and adverse effects were reported. Seizure frequency and number of antiepileptic drugs were compared between those actively using cannabis products and those who were not. Longitudinal analysis was performed on a subset of the study population to compare these same variables at pre-treatment and post-treatment time points.

RESULTS

Three hundred and twelve caregivers answered questions regarding their child's use of antiepileptic medications. Of these, 82 (26%) described use of cannabis preparations either at present, or in the past, with the most common being cannabidiol. Of 70 caregivers that described their perceived effect on seizure control, more than two thirds reported an improvement in seizure control, either temporary (16%) or lasting (54%). Additional benefits included improvements in attention, cognition, and sleep. The majority of responses (78%) described adverse effects as 'none', though some reported an increase in sedation and gastrointestinal upset. There was no reduction in the median seizure frequency nor the number of different antiepileptic drugs, for those who were actively using cannabis products compared to those who were not. Similarly, individuals who were not using cannabis products at an initial time point had no differences in seizure frequency nor number of antiepileptic drugs at a second timepoint when they had started using this treatment.

CONCLUSIONS

Although this is an observational study, limited by potential participation bias and the unreliable nature of unblinded self-assessment, it suggests that caregivers perceive cannabis products, especially cannabidiol, to have a tolerable adverse effect profile and adequate efficacy. Despite this, cannabis was not associated with a reduction in seizure frequency nor number of antiepileptic drugs when compared to non-users or when compared to pre-treatment. Randomized controlled trials are urgently needed to more reliably assess this treatment's safety and efficacy.