Prophylactic administration of cannabidiol reduces microglial inflammatory response to kainate-induced seizures and neurogenesis


“Microglia, the dynamic innate immune cells of the central nervous system, become activated in epilepsy. The process of microglial activation in epilepsy results in the creation of an inflammatory environment around the site of seizure onset, which contributes to the epileptogenic process and epilepsy progression. Cannabidiol (CBD) has been effective for use as an adjunctive treatment for two severe pediatric seizure disorders. Newly recognized as an Food and Drug Administration (FDA)-approved drug treatment in epilepsy, it has gained in popularity primarily for pain management. Although CBD is readily available in stores and online retailers, its mechanism of action and specifically its effects on microglia and their functions are yet fully understood. In this study, we examine the effects of commercially available CBD on microglia inflammatory activation and neurogenic response, in the presence and absence of seizures. We use systemic administration of kainate to elicit seizures in mice, which are assessed behaviorally. Artisanal CBD is given in different modes of administration and timing to dissect its effect on seizure intensity, microglial activation and aberrant seizure-related neurogenesis. CBD significantly dampens microglial migration and accumulation to the hippocampus. While long term artisanal CBD use does not prevent or lessen seizure severity, CBD is a promising adjunctive partner for its ability to depress epileptogenic processes. These studies indicate that artisanal CBD is beneficial as it both decreases inflammation in the CNS and reduces the number of ectopic neurons deposited in the hippocampal area post seizure.”

A nutraceutical product, extracted from Cannabis sativa, modulates voltage-gated sodium channel function

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“Background: Purified cannabidiol (CBD), a non-psychoactive phytocannabinoid, has gained regulatory approval to treat intractable childhood epilepsies. Despite this, artisanal and commercial CBD-dominant hemp-based products continue to be used by epilepsy patients. Notably, the CBD doses used in these latter products are much lower than that found to be effective in reducing seizures in clinical trials with purified CBD. This might be because these CBD-dominant hemp products contain other bioactive compounds, including phytocannabinoids and terpenes, which may exert unique effects on epilepsy-relevant drug targets. Voltage-gated sodium (NaV) channels are vital for initiation of neuronal action potential propagation and genetic mutations in these channels result in epilepsy phenotypes. Recent studies suggest that NaV channels are inhibited by purified CBD. However, the effect of cannabis-based products on the function of NaV channels is unknown.

Methods: Using automated-planar patch-clamp technology, we profile a hemp-derived nutraceutical product (NP) against human NaV1.1-NaV1.8 expressed in mammalian cells to examine effects on the biophysical properties of channel conductance, steady-state fast inactivation and recovery from fast inactivation.

Results: NP modifies peak current amplitude of the NaV1.1-NaV1.7 subtypes and has variable effects on the biophysical properties for all channel subtypes tested. NP potently inhibits NaV channels revealing half-maximal inhibitory concentration (IC50) values of between 1.6 and 4.2 μg NP/mL. Purified CBD inhibits NaV1.1, NaV1.2, NaV1.6 and NaV1.7 to reveal IC50 values in the micromolar range. The CBD content of the product equates to IC50 values (93-245 nM), which are at least an order of magnitude lower than purified CBD. Unlike NP, hemp seed oil vehicle alone did not inhibit NaV channels, suggesting that the inhibitory effects of NP are independent of hemp seed oil.

Conclusions: This CBD-dominant NP potently inhibits NaV channels. Future study of the individual elements of NP, including phytocannabinoids and terpenes, may reveal a potent individual component or that its components interact to modulate NaV channels.”

Antiseizure Effects of Cannabidiol Leading to Increased Peroxisome Proliferator-Activated Receptor Gamma Levels in the Hippocampal CA3 Subfield of Epileptic Rats


“We evaluated the effects of cannabidiol (CBD) on seizures and peroxisome proliferator-activated receptor gamma (PPARγ) levels in an animal model of temporal lobe epilepsy (TLE). Adult male Sprague-Dawley rats were continuously monitored by video-electrocorticography up to 10 weeks after an intraperitoneal kainic acid (15 mg/kg) injection. Sixty-seven days after the induction of status epilepticus and the appearance of spontaneous recurrent seizures in all rats, CBD was dissolved in medium-chain triglyceride (MCT) oil and administered subcutaneously at 120 mg/kg (n = 10) or 12 mg/kg (n = 10), twice a day for three days. Similarly, the vehicle was administered to ten epileptic rats. Brain levels of PPARγ immunoreactivity were compared to those of six healthy controls. CBD at 120 mg/kg abolished the seizures in 50% of rats (p = 0.033 vs. pre-treatment, Fisher’s exact test) and reduced total seizure duration (p < 0.05, Tukey Test) and occurrence (p < 0.05). PPARγ levels increased with CBD in the hippocampal CA1 subfield and subiculum (p < 0.05 vs. controls, Holm-Šidák test), but only the highest dose increased the immunoreactivity in the hippocampal CA3 subfield (p < 0.001), perirhinal cortex, and amygdala (p < 0.05). Overall, these results suggest that the antiseizure effects of CBD are associated with upregulation of PPARγ in the hippocampal CA3 region.”

Long-term cannabidiol treatment for seizures in patients with tuberous sclerosis complex: An open-label extension trial

“Objective: To evaluate the long-term safety and efficacy of add-on cannabidiol (CBD) in patients with seizures associated with tuberous sclerosis complex (TSC) in the open-label extension (OLE) of the randomized, placebo-controlled phase 3 trial GWPCARE6 (NCT02544763). Results of an interim (February 2019 data cut) analysis are reported.

Methods: Patients who completed the randomized trial enrolled to receive CBD (Epidiolex® in the United States; Epidyolex® in the EU; 100 mg/mL oral solution). The initial target dose was 25 mg/kg/day, which, based on response and tolerability, could be decreased or increased up to 50 mg/kg/day. The primary end point was safety. Key secondary end points included percentage reduction in TSC-associated (countable focal and generalized) seizures, responder rates, and Subject/Caregiver Global Impression of Change (S/CGIC).

Results: Of 201 patients who completed the randomized phase, 199 (99%) entered the OLE. Mean age was 13 years (range, 1-57). At the time of analysis, 5% of patients had completed treatment, 20% had withdrawn, and 75% were ongoing. One-year retention rate was 79%. Median treatment time was 267 days (range, 18-910) at a 27 mg/kg/day mean modal dose. Most patients (92%) had an adverse event (AE). Most common AEs were diarrhea (42%), seizure (22%), and decreased appetite (20%). AEs led to permanent discontinuation in 6% of patients. There was one death that was deemed treatment unrelated by the investigator. Elevated liver transaminases occurred in 17 patients (9%) patients; 12 were taking valproate. Median percentage reductions in seizure frequency (12-week windows across 48 weeks) were 54%-68%. Seizure responder rates (≥50%, ≥75%, 100% reduction) were 53%-61%, 29%-45%, and 6%-11% across 12-week windows for 48 weeks. Improvement on the S/CGIC scale was reported by 87% of patients/caregivers at 26 weeks.

Significance: In patients with TSC, long-term add-on CBD treatment was well tolerated and sustainably reduced seizures through 48 weeks, with most patients/caregivers reporting global improvement.”

“The results of our study show that add-on CBD can be an efficacious long-term treatment for TSC-associated seizures with manageable side effects and has been approved in patients as young as 1 year of age in the United States.”

Antiseizure Effects of Fully Characterized Non-Psychoactive Cannabis sativa L. Extracts in the Repeated 6-Hz Corneal Stimulation Test


“Compounds present in Cannabis sativa L. preparations have recently attracted much attention in the treatment of drug-resistant epilepsy. Here, we screened two olive oil extracts from a non-psychoactive C. sativa variety, fully characterized by high-performance liquid chromatography and gas chromatography. Particularly, hemp oils with different concentrations of terpenes were administered at the same dose of cannabidiol (25 mg/kg/day orally), 1 h before the 6-Hz corneal stimulation test (44 mA). Mice were stimulated once a day for 5 days and evaluated by video-electrocorticographic recordings and behavioral analysis. Neuronal activation was assessed by FosB/ΔFosB immunoreactivity. Both oils significantly reduced the percentage of mice experiencing convulsive seizures in comparison to olive oil-treated mice (p < 0.050; Fisher’s exact test), but only the oil enriched with terpenes (K2) significantly accelerated full recovery from the seizure. These effects occurred in the presence of reduced power of delta rhythm, and, instead, increased power of theta rhythm, along with a lower FosB/ΔFosB expression in the subiculum (p < 0.050; Duncan’s method). The overall findings suggest that both cannabinoids and terpenes in oil extracts should be considered as potential therapeutic agents against epileptic seizures and epilepsy.”

Long-term use of cannabidiol-enriched medical cannabis in a prospective cohort of children with drug-resistant developmental and epileptic encephalopathy

Epilepsy Action

“Objective: We report our findings regarding effectiveness, safety, and tolerability of cannabidiol (CBD)-enriched medical cannabis as add-on therapy in children with drug-resistant epileptic encephalopathies (DEEs) after a median follow-up of 20 months.

Methods: A prospective cohort study was conducted to assess effectiveness, safety, and tolerability of CBD-enriched medical cannabis oil added to standard antiseizure medications in children with drug-resistant DEE seen at a single center.

Results: Between October 2018 and March 2020, 59 patients were enrolled. Mean age at enrollment was 10.5 years (range, 2-17 years). Median treatment duration was 20 months (range, 12-32). Median age at first seizure was 8 months (range, 1 day – 10 years). At the end of follow-up, 78% of the children had a ≥ 50% decrease in seizure frequency and 47.5% had a > 75% decrease. Seven patients (11.9%) were seizure free. The number of seizures was reduced from a median of 305/month to 90/month, amounting to a mean reduction of 57% and a median reduction of 71% (p < 0.0001). Adverse effects were mostly mild or moderate. CBD was discontinued in 17 patients (28.8%) due to lack of response to treatment, increased seizure frequency, intolerance to the drug, or poor compliance.

Conclusion: In children with drug-resistant DEEs, long-term treatment of CBD-enriched medical cannabis as an adjuvant therapy to antiseizure therapy was found to be safe, well tolerated, and effective. Sustained reductions in seizure frequency and improvement of aspects of daily living were observed compared to our preliminary findings.”

  • “•Long-term use of CBD-enriched medical cannabis as add-on treatment seems safe and effective in DEE.
  • The drug was well tolerated and had a positive impact on aspects of daily living.
  • Good results were found in patients with LGS and DS, as well as those with DEEs other than LGS and DS.
  • No tolerance to CBD-enriched medical cannabis was observed in any of the children.”

A narrative review of molecular mechanism and therapeutic effect of cannabidiol (CBD)

“Cannabidiol (CBD) is an abundant non-psychoactive phytocannabinoid in cannabis extracts which has high affinity on a series of receptors, including Type 1 cannabinoid receptor (CB1), Type 2 cannabinoid receptor (CB2), GPR55, transient receptor potential vanilloid (TRPV) and peroxisome proliferator-activated receptor gamma (PPARγ). By modulating the activities of these receptors, CBD exhibits multiple therapeutic effects, including neuroprotective, antiepileptic, anxiolytic, antipsychotic, anti-inflammatory, analgesic and anticancer properties. CBD could also be applied to treat or prevent COVID-19 and its complications. Here, we provide a narrative review of CBD’s applications in human diseases: from mechanism of action to clinical trials.”

“The herbal use of Cannabis sativa plant extract (also known as cannabis, hemp or marijuana) can be tracked back to ancient China, around 2900 BC.  Cannabidiol (CBD) is one of the most abundant extracts from C. sativa; it has multiple bioactivities and wide health benefits without psychoactive properties. In this review, we summarized the molecular mechanisms and clinical experience in support of CBD as a potential therapeutic compound for various diseases.”

Spinal astroglial cannabinoid receptors control pathological tremor

Nature Neuroscience“Cannabinoids reduce tremor associated with motor disorders induced by injuries and neurodegenerative disease. Here we show that this effect is mediated by cannabinoid receptors on astrocytes in the ventral horn of the spinal cord, where alternating limb movements are initiated. We first demonstrate that tremor is reduced in a mouse model of essential tremor after intrathecal injection of the cannabinoid analog WIN55,212-2. We investigate the underlying mechanism using electrophysiological recordings in spinal cord slices and show that endocannabinoids released from depolarized interneurons activate astrocytic cannabinoid receptors, causing an increase in intracellular Ca2+, subsequent release of purines and inhibition of excitatory neurotransmission. Finally, we show that the anti-tremor action of WIN55,212-2 in the spinal cords of mice is suppressed after knocking out CB1 receptors in astrocytes. Our data suggest that cannabinoids reduce tremor via their action on spinal astrocytes.”

“Medical cannabis can reduce essential tremor: Turns on overlooked cells in central nervous system”

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.”

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.”