The Endocannabinoid System: A Potential Target for the Treatment of Various Diseases

ijms-logo“The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems.

In addition to regulating physiological processes, the ECS directly influences anxiety, feeding behaviour/appetite, emotional behaviour, depression, nervous functions, neurogenesis, neuroprotection, reward, cognition, learning, memory, pain sensation, fertility, pregnancy, and pre-and post-natal development.

The ECS is also involved in several pathophysiological diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases. In recent years, genetic and pharmacological manipulation of the ECS has gained significant interest in medicine, research, and drug discovery and development.

The distribution of the components of the ECS system throughout the body, and the physiological/pathophysiological role of the ECS-signalling pathways in many diseases, all offer promising opportunities for the development of novel cannabinergic, cannabimimetic, and cannabinoid-based therapeutic drugs that genetically or pharmacologically modulate the ECS via inhibition of metabolic pathways and/or agonism or antagonism of the receptors of the ECS. This modulation results in the differential expression/activity of the components of the ECS that may be beneficial in the treatment of a number of diseases.

This manuscript in-depth review will investigate the potential of the ECS in the treatment of various diseases, and to put forth the suggestion that many of these secondary metabolites of Cannabis sativa L. (hereafter referred to as “C. sativa L.” or “medical cannabis”), may also have potential as lead compounds in the development of cannabinoid-based pharmaceuticals for a variety of diseases.”

https://pubmed.ncbi.nlm.nih.gov/34502379/

https://www.mdpi.com/1422-0067/22/17/9472

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Cannabigerolic acid, a major biosynthetic precursor molecule in cannabis, exhibits divergent effects on seizures in mouse models of epilepsy

British Journal of Pharmacology“Background and purpose: Cannabis has been used to treat epilepsy for millennia, with such use validated by regulatory approval of cannabidiol (CBD) for the treatment of Dravet syndrome. Unregulated artisanal cannabis-based products used to treat children with intractable epilepsies often contain relatively low doses of CBD but are enriched in other phytocannabinoids. This raises the possibility that other cannabis constituents might have anticonvulsant properties.

Experimental approach: We used the Scn1a+/- mouse model of Dravet syndrome to interrogate the cannabis plant for phytocannabinoids with anticonvulsant effects against hyperthermia-induced seizures. The most promising, cannabigerolic acid (CBGA), was further examined against spontaneous seizures and survival in Scn1a+/- mice. CBGA was also examined in conventional electroshock seizure models. In addition, we surveyed the pharmacological effects of CBGA across multiple drug targets.

Key results: The initial screen identified three phytocannabinoids with novel anticonvulsant properties: CBGA, cannabidivarinic acid (CBDVA) and cannabigerovarinic acid (CBGVA). CBGA was the most potent and potentiated the anticonvulsant effects of clobazam against hyperthermia-induced and spontaneous seizures, and was anticonvulsant in the MES threshold test. However, CBGA was proconvulsant in the 6-Hz threshold test and a high dose increased spontaneous seizure frequency in Scn1a+/- mice. CBGA was found to interact with numerous epilepsy-relevant targets including GPR55, TRPV1 channels and GABAA receptors.

Conclusion: These results suggest CBGA, CBDVA and CBGVA may contribute to the effects of cannabis-based products in childhood epilepsy. While these phytocannabinoids have anticonvulsant potential and could be lead compounds for drug development programs, several liabilities would need to be overcome before CBD is superseded by another in this class.”

https://pubmed.ncbi.nlm.nih.gov/34384142/

https://bpspubs.onlinelibrary.wiley.com/doi/10.1111/bph.15661

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Add-on cannabidiol in patients with Dravet syndrome: Results of a long-term open-label extension trial

“Objective: Add-on cannabidiol (CBD) reduced seizures associated with Dravet syndrome (DS) in two randomized, double-blind, placebo-controlled trials: GWPCARE1 Part B (NCT02091375) and GWPCARE2 (NCT02224703). Patients who completed GWPCARE1 Part A (NCT02091206) or Part B, or GWPCARE2, were enrolled in a long-term open-label extension trial, GWPCARE5 (NCT02224573). We present an interim analysis of the safety, efficacy, and patient-reported outcomes from GWPCARE5.

Methods: Patients received a pharmaceutical formulation of highly purified CBD in oral solution (100 mg/ml), titrated from 2.5 to 20 mg/kg/day over a 2-week period, added to their existing medications. Based on response and tolerance, CBD could be reduced or increased to 30 mg/kg/day.

Results: Of the 330 patients who completed the original randomized trials, 315 (95%) enrolled in this open-label extension. Median treatment duration was 444 days (range = 18-1535), with a mean modal dose of 22 mg/kg/day; patients received a median of three concomitant antiseizure medications. Adverse events (AEs) occurred in 97% patients (mild, 23%; moderate, 50%; severe, 25%). Commonly reported AEs were diarrhea (43%), pyrexia (39%), decreased appetite (31%), and somnolence (28%). Twenty-eight (9%) patients discontinued due to AEs. Sixty-nine (22%) patients had liver transaminase elevations >3 × upper limit of normal; 84% were on concomitant valproic acid. In patients from GWPCARE1 Part B and GWPCARE2, the median reduction from baseline in monthly seizure frequency assessed in 12-week periods up to Week 156 was 45%-74% for convulsive seizures and 49%-84% for total seizures. Across all visit windows, ≥83% patients/caregivers completing a Subject/Caregiver Global Impression of Change scale reported improvement in overall condition.

Significance: We show that long-term CBD treatment had an acceptable safety profile and led to sustained, clinically meaningful reductions in seizure frequency in patients with treatment-resistant DS.”

https://pubmed.ncbi.nlm.nih.gov/34406656/

https://onlinelibrary.wiley.com/doi/10.1111/epi.17036

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Cannabidiol interactions with voltage-gated sodium channels

eLife logo “Voltage-gated sodium channels are targets for a range of pharmaceutical drugs developed for treatment of neurological diseases.

Cannabidiol (CBD), the non-psychoactive compound isolated from cannabis plants, was recently approved for treatment of two types of epilepsy associated with sodium channel mutations.

This study used high resolution X-ray crystallography to demonstrate the detailed nature of the interactions between CBD and the NavMs voltage-gated sodium channel, and electrophysiology to show the functional effects of binding CBD to these channels.

CBD binds at a novel site at the interface of the fenestrations and the central hydrophobic cavity of the channel. Binding at this site blocks the transmembrane-spanning sodium ion translocation pathway, providing a molecular mechanism for channel inhibition. Modelling studies suggest why the closely-related psychoactive compound tetrahydrocannabinol may not have the same effects on these channels. Finally, comparisons are made with the TRPV2 channel, also recently proposed as a target site for CBD.

In summary, this study provides novel insight into a possible mechanism for CBD interactions with sodium channels.”

https://pubmed.ncbi.nlm.nih.gov/33089780/

https://elifesciences.org/articles/58593

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Practical use of pharmaceutically purified oral cannabidiol in Dravet syndrome and Lennox-Gastaut syndrome

Publication Cover “Pharmaceutically purified oral cannabidiol (CBD) has been recently approved by the US Food and Drug Administration and European Medicines Agency as treatment of seizures associated with Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS), which are severe and difficult-to-treat developmental and epileptic encephalopathies with onset in early childhood.

Areas covered: This review will critically review the pharmacokinetic properties of CBD, the interactions with antiseizure and non-antiseizure medications, and the main tolerability and safety issues to provide guidance for its use in everyday practice.

Expert opinion: CBD is metabolized in the liver and can influence the activity of enzymes involved in drug metabolism. The best characterized drug-drug interaction is between CBD and clobazam. The most common adverse events include somnolence, gastrointestinal discomfort and increase in serum transaminases.

High-grade purified CBD oral solution represents an effective therapeutic option in patients with DS and LGS.

The findings cannot be extrapolated to other cannabis-based products, synthetic cannabinoids for medicinal use and non-medicinal cannabis and CBD derivatives.”

https://pubmed.ncbi.nlm.nih.gov/33026899/

“Pharmaceutically purified oral cannabidiol (CBD) is approved for treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome.”

https://www.tandfonline.com/doi/abs/10.1080/14737175.2021.1834383?journalCode=iern20

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Development of cannabidiol as a treatment for severe childhood epilepsies

“In recent years there has been a growing appreciation by regulatory authorities that cannabis-based medicines can play a useful role in disease therapy.

Although often conflagrated by proponents of recreational use, the legislative rescheduling of cannabis-derived compounds, such as cannabidiol (CBD), has been associated with the steady increase in the pursuit of use of medicinal cannabis.

One key driver in this interest has been the scientific demonstration of efficacy and safety of CBD in randomised, placebo-controlled clinical trials in children and young adults with difficult-to-treat epilepsies, which has encouraged increasing numbers of human trials of CBD for other indications and in other populations.

The introduction of CBD as the medicine Epidiolex in the US (in 2018) and as Epidyolex in the EU (in 2019) as the first cannabis-derived therapeutic for the treatment for seizures was underpinned by preclinical research performed at the University of Reading.

This work was awarded the British Pharmacological Society Sir James Black Award for Contributions to Drug Discovery 2019 and is discussed in the following review article.”

https://pubmed.ncbi.nlm.nih.gov/32986848/

https://bpspubs.onlinelibrary.wiley.com/doi/10.1111/bph.15274

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Clinical implications of trials investigating drug-drug interactions between cannabidiol and enzyme inducers or inhibitors or common antiseizure drugs

“Highly purified cannabidiol (CBD) has demonstrated efficacy with an acceptable safety profile in patients with Lennox-Gastaut syndrome or Dravet syndrome in randomized, double-blind, add-on, controlled phase 3 trials.

It is important to consider the possibility of drug-drug interactions (DDIs). Here, we review six trials of CBD (Epidiolex/Epidyolex; 100 mg/mL oral solution) in healthy volunteers or patients with epilepsy, which investigated potential interactions between CBD and enzymes involved in drug metabolism of common antiseizure drugs (ASDs).

CBD did not affect CYP3A4 activity. Induction of CYP3A4 and CYP2C19 led to small reductions in exposure to CBD and its major metabolites. Inhibition of CYP3A4 activity did not affect CBD exposure and caused small increases in exposure to CBD metabolites. Inhibition of CYP2C19 activity led to a small increase in exposure to CBD and small decreases in exposure to CBD metabolites.

One potentially clinically important DDI was identified: combination of CBD and clobazam (CLB) did not affect CBD or CLB exposure, but increased exposure to major metabolites of both compounds. Reduction of CLB dose may be considered if adverse reactions known to occur with CLB are experienced when it is coadministered with CBD.

There was a small increase of exposure to stiripentol (STP) when coadministered with CBD. STP had no effect on CBD exposure but led to minor decreases in exposure to CBD metabolites. Combination of CBD and valproate (VPA) did not cause clinically important changes in the pharmacokinetics of either drug, or 2-propyl-4-pentenoic acid. Concomitant VPA caused small increases in exposure to CBD metabolites. Dose adjustments are not likely to be necessary when CBD is combined with STP or VPA.

The safety results from these trials were consistent with the known safety profile of CBD. These trials indicate an overall low potential for DDIs between CBD and other ASDs, except for CLB.”

https://pubmed.ncbi.nlm.nih.gov/32918835/

https://onlinelibrary.wiley.com/doi/full/10.1111/epi.16674

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Add-on cannabidiol significantly decreases seizures in 3 patients with SYNGAP1 developmental and epileptic encephalopathy

“Mutations in SYNGAP1 are associated with developmental delay, epilepsy, and autism spectrum disorder (ASD). Epilepsy is often drug-resistant in this syndrome with frequent drop attacks.

In a prospective study of add-on cannabidiol (CBD), we identified three patients with SYNGAP1 mutations: two boys and one girl. Seizure onset was at 3.5, 8, and 18 months (M), respectively, with numerous atypical absences per day associated with eyelid myoclonia (2/3 patients), upper limb myoclonic jerks (2/3 patients), and drop attacks (all patients). Seizures were resistant to at least 5 antiepileptic drugs (AEDs).

After CBD introduction, two patients were responders since M2 and achieve a seizure reduction of 90% and 80%, respectively, at M9 with disappearance of drop attacks. EEGs showed an improvement regarding background activity and interictal anomalies. The last patient showed a late response at M7 of treatment with an 80% decrease in seizure frequency. Caregiver in all three evaluated as much improved the status of their children. Treatment was well-tolerated in all, and no major adverse events (AEs) were reported.

CBD showed efficacy in patients with drug-resistant epilepsy due to SYNGAP1 mutations. Other patients with rare genetic developmental and epileptic encephalopathies with drug-resistant epilepsies might benefit from CBD.”

https://pubmed.ncbi.nlm.nih.gov/32913957/

“CBD add‐on therapy in patients with SYNGAP1 encephalopathy showed a good response in three patients with a good safety profile and a late response in one patient. This therapy should be included in the treatment algorithm of patients with SYNGAP1 mutations presenting drug resistance epilepsy and might be expanded to other rare genetic epilepsies that might not be included in formal trials.”

https://onlinelibrary.wiley.com/doi/full/10.1002/epi4.12411

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Receptors and Channels Possibly Mediating the Effects of Phytocannabinoids on Seizures and Epilepsy

pharmaceuticals-logo“Epilepsy contributes to approximately 1% of the global disease burden. By affecting especially young children as well as older persons of all social and racial variety, epilepsy is a present disorder worldwide. Currently, only 65% of epileptic patients can be successfully treated with antiepileptic drugs. For this reason, alternative medicine receives more attention.

Cannabis has been cultivated for over 6000 years to treat pain and insomnia and used since the 19th century to suppress epileptic seizures.

The two best described phytocannabinoids, (-)-trans9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are claimed to have positive effects on different neurological as well as neurodegenerative diseases, including epilepsy.

There are different cannabinoids which act through different types of receptors and channels, including the cannabinoid receptor 1 and 2 (CB1, CB2), G protein-coupled receptor 55 (GPR55) and 18 (GPR18), opioid receptor µ and δ, transient receptor potential vanilloid type 1 (TRPV1) and 2 (TRPV2), type A γ-aminobutyric acid receptor (GABAAR) and voltage-gated sodium channels (VGSC).

The mechanisms and importance of the interaction between phytocannabinoids and their different sites of action regarding epileptic seizures and their clinical value are described in this review.”

https://pubmed.ncbi.nlm.nih.gov/32751761/

https://www.mdpi.com/1424-8247/13/8/174

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Cannabidiol inhibits febrile seizure by modulating AMPA receptor kinetics through its interaction with the N-terminal domain of GluA1/GluA2

Pharmacological Research “Cannabidiol (CBD) is a major phytocannabinoid in Cannabis sativa. CBD is being increasingly reported as a clinical treatment for neurological diseases.

Febrile seizure is one of the most common diseases in children with limited therapeutic options. We investigated possible therapeutic effects of CBD on febrile seizures and the underlying mechanism.

Use of a hyperthermia-induced seizures model revealed that CBD significantly prolonged seizure latency and reduced the severity of thermally-induced seizures. Hippocampal neuronal excitability was significantly decreased by CBD. Further, CBD significantly reduced the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) mediated evoked excitatory postsynaptic currents (eEPSCs) and the amplitude and frequency of miniature EPSCs (mEPSCs).

Furthermore, CBD significantly accelerated deactivation in GluA1 and GluA2 subunits. Interestingly, CBD slowed receptor recovery from desensitization of GluA1, but not GluA2. These effects on kinetics were even more prominent when AMPAR was co-expressed with γ-8, the high expression isoform 8 of transmembrane AMPAR regulated protein (TARPγ8) in the hippocampus. The inhibitory effects of CBD on AMPAR depended on its interaction with the distal N-terminal domain of GluA1/GluA2.

CBD inhibited AMPAR activity and reduced hippocampal neuronal excitability, thereby improving the symptoms of febrile seizure in mice. The putative binding site of CBD in the N-terminal domain of GluA1/GluA2 may be a drug target for allosteric gating modulation of AMPAR.”

https://pubmed.ncbi.nlm.nih.gov/32805354/

“Cannabidiol (CBD) significantly prolonged seizure latency and reduced seizure severity.”

https://www.sciencedirect.com/science/article/abs/pii/S1043661820314365?via%3Dihub

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