An evaluation of the anti-hyperalgesic effects of cannabidiolic acid-methyl ester (CBDA-ME) in a preclinical model of peripheral neuropathic pain.

Posted on January 29, 2020 by David Worrell

Publication cover image “Chronic neuropathic pain (NEP) is associated with growing therapeutic cannabis use. To promote quality of life without psychotropic effects, cannabinoids other than Δ9-tetrahydrocannabidiol, including cannabidiol and its precursor cannabidiolic acid (CBDA), are being evaluated. Due to its instability, CBDA has been understudied, particularly as an anti-nociceptive agent. Adding a methyl ester group (CBDA-ME) significantly enhances its stability, facilitating analyses of its analgesic effects in vivo. This study examines early treatment efficacy of CBDA-ME in a rat model of peripherally induced NEP and evaluates sex as a biological variable.

KEY RESULTS:

In males, CBDA-ME elicited a significant concentration-dependent chronic anti-hyperalgesic effect, also influencing both nociceptive and non-nociceptive mechanoreceptors, which were not observed in females at any of the concentrations tested.

CONCLUSION AND IMPLICATIONS:

Initiating treatment of a peripheral nerve injury with CBDA-ME at an early stage post-surgery provides anti-nociception in males, warranting further investigation into potential sexual dimorphisms underlying this response.”

https://www.ncbi.nlm.nih.gov/pubmed/31981216

https://bpspubs.onlinelibrary.wiley.com/doi/abs/10.1111/bph.14997

The Role of Cannabidiol (CBD) in Chronic Pain Management: An Assessment of Current Evidence.

Posted on January 29, 2020 by David Worrell

“Given the growing challenges in chronic pain management coupled with the ongoing consequences of the opioid epidemic, pain management practitioners are looking into more effective, innovative, and safer alternatives to treat pain.

Cannabis-based medicine had been described for hundreds of years but only recently have we seen the more scientific, evidence-based approach to its use, and ongoing investigations continue to explore its potential medical benefits.

While historically more attention has been paid to the psychoactive component of the cannabis plant Δ⁹-tetrahydrocannabinol (THC), there have been fewer scientific studies on the medical use of the cannabidiol (CBD) – a non-psychoactive component of the cannabis plant.

RECENT FINDINGS:

By examining recent literature, we investigated the use of CBD and its potential role in pain management. Since there are currently no approved pharmaceutical products that contain CBD alone for the management of pain, this review focused on nabiximols (which is a combined product of THC/CBD in a 1:1 ratio) as the only pharmaceutical product available that contains CBD and is being used for the management of pain.

It is difficult to definitely attribute the therapeutic properties to CBD alone since it is always administered with THC.

Based on the available literature, it is difficult to make a recommendation for the use of CBD in chronic pain management. It is also important to note that there are many CBD products currently available as supplements, but these products are non-pharmaceuticals and lack the appropriate clinical studies to support their efficacy claims.”

https://www.ncbi.nlm.nih.gov/pubmed/31980957

https://link.springer.com/article/10.1007%2Fs11916-020-0835-4

Abnormal Cannabidiol Affects Production of Pro-Inflammatory Mediators and Astrocyte Wound Closure in Primary Astrocytic-Microglial Cocultures.

Posted on January 29, 2020 by David Worrell

“Abnormal cannabidiol (abn-CBD) exerts neuroprotective effects in vivo and in vitro. In the present study, we investigated the impact of abn-CBD on the glial production of proinflammatory mediators and scar formation within in vitro models. Primary astrocytic-microglial cocultures and astrocytic cultures from neonatal C57BL/6 mice and CB₂ receptor knockout mice were stimulated with lipopolysaccharide (LPS), and the concentrations of tumor necrosis factor α (TNFα), interleukin-6 (IL-6) and nitrite were determined. Furthermore, we performed a live cell microscopy-based scratch-wound assay. After LPS stimulation, TNFα, IL-6 and nitrite production was more strongly increased in cocultures than in isolated astrocytes. Abn-CBD treatment attenuated the LPS-induced production of TNFα and nitrite in cocultures, while IL-6 production remained unaltered. In isolated astrocytes, only LPS-induced TNFα production was reduced by abn-CBD. Similar effects were observed after abn-CBD application in cocultures of CB₂ knockout mice. Interestingly, LPS-induced TNFα and nitrite levels were far lower in CB₂ knockout cultures compared to wildtypes, while IL-6 levels did not differ. In the scratch-wound assay, treatment with abn-CBD decelerated wound closure when microglial cells were present. Our data shows a differential role of abn-CBD for modulation of glial inflammation and astrocytic scar formation. These findings provide new explanations for mechanisms behind the neuroprotective potential of abn-CBD.”

https://www.ncbi.nlm.nih.gov/pubmed/31979350

https://www.mdpi.com/1420-3049/25/3/496

Phytocannabinoids in Neurological Diseases: Could They Restore a Physiological GABAergic Transmission?

Posted on January 29, 2020 by David Worrell

“γ-Aminobutyric acid type A receptors (GABA_ARs) are the main inhibitory mediators in the central nervous system (CNS). GABA_ARs are pentameric ligand gated ion channels, and the main subunit composition is usually 2α2βγ, with various isotypes assembled within a set of 19 different subunits. The inhibitory function is mediated by chloride ion movement across the GABA_ARs, activated by synaptic GABA release, reducing neuronal excitability in the adult CNS. Several studies highlighted the importance of GABA-mediated transmission during neuro-development, and its involvement in different neurological and neurodevelopmental diseases, from anxiety to epilepsy. However, while it is well known how different classes of drugs are able to modulate the GABA_ARs function (benzodiazepines, barbiturates, neurosteroids, alcohol), up to now little is known about GABA_ARs and cannabinoids interaction in the CNS. Endocannabinoids and phytocannabinoids are lately emerging as a new class of promising drugs for a wide range of neurological conditions, but their safety as medication, and their mechanisms of action are still to be fully elucidated. In this review, we will focus our attention on two of the most promising molecules (Δ9-tetrahydrocannabinol; Δ9-THC and cannabidiol; CBD) of this new class of drugs and their possible mechanism of action on GABA_ARs.”

https://www.ncbi.nlm.nih.gov/pubmed/31979108

https://www.mdpi.com/1422-0067/21/3/723

Allosteric Cannabinoid Receptor 1 (CB1) Ligands Reduce Ocular Pain and Inflammation.

Posted on January 25, 2020 by David Worrell

“Cannabinoid receptor 1 (CB1) activation has been reported to reduce transient receptor potential cation channel subfamily V member 1 (TRPV1)-induced inflammatory responses and is anti-nociceptive and anti-inflammatory in corneal injury.

We examined whether allosteric ligands, can modulate CB1 signaling to reduce pain and inflammation in corneal hyperalgesia.

Corneal hyperalgesia was generated by chemical cauterization of cornea in wildtype and CB2 knockout (CB2^-/-) mice. The novel racemic CB1 allosteric ligand GAT211 and its enantiomers GAT228 and GAT229 were examined alone or in combination with the orthosteric CB1 agonist Δ⁸-tetrahydrocannabinol (Δ⁸-THC). Pain responses were assessed following capsaicin (1 µM) stimulation of injured corneas at 6 h post-cauterization. Corneal neutrophil infiltration was also analyzed. GAT228, but not GAT229 or GAT211, reduced pain scores in response to capsaicin stimulation.

Combination treatments of 0.5% GAT229 or 1% GAT211 with subthreshold Δ⁸-THC (0.4%) significantly reduced pain scores following capsaicin stimulation. The anti-nociceptive effects of both GAT229 and GAT228 were blocked with CB1 antagonist AM251, but remained unaffected in CB2^-/- mice. Two percent GAT228, or the combination of 0.2% Δ⁸-THC with 0.5% GAT229 also significantly reduced corneal inflammation.

CB1 allosteric ligands could offer a novel approach for treating corneal pain and inflammation.”

https://www.ncbi.nlm.nih.gov/pubmed/31968549

https://www.mdpi.com/1420-3049/25/2/417

The effect of orally administered dronabinol on optic nerve head blood flow in healthy subjects- a randomized clinical trial.

Posted on January 25, 2020 by David Worrell

Publication cover image “It has been hypothesized that besides its intraocular pressure (IOP) lowering potential, tetrahydrocannabinol (THC) may also improve ocular hemodynamics.

The aim of the present study was to investigate whether single oral administration of dronabinol, a synthetic THC, alters optic nerve head blood flow (ONHBF) and its regulation in healthy subjects.

The study was carried out in a randomized, placebo-controlled, double-masked, two-way crossover design in twenty-four healthy subjects. For each study participant, two study days were scheduled, on which they either received capsules containing 5mg dronabinol or placebo. ONHBF was measured with laser Doppler flowmetry at rest and while the study participants performed isometric exercise for six minutes to increase mean arterial blood pressure (MAP). This was repeated one hour after drug intake. Ocular perfusion pressure (OPP) was calculated as 2/3MAP-IOP.

Dronabinol was well tolerated and no cannabinoid-related psychoactive effects were reported.

Neither administration of dronabinol nor placebo had an effect on IOP, MAP or OPP. In contrast, dronabinol significantly increased ONHBF at rest by 9.5±8.1% whereas placebo did not show a change in ONHBF (0.3±7.4% vs. baseline, p<0.001 between study days). Dronabinol did not alter the autoregulatory response of ONHBF to isometric exercise.

In conclusion, the present data indicate that low dose dronabinol increases ONHBF in healthy subjects without affecting IOP, OPP or inducing psychoactive side effects. In addition, dronabinol does not alter the autoregulatory response of ONHBF to an experimental increase in OPP. Further studies are needed to investigate whether this effect can also be observed in glaucoma patients.”

https://www.ncbi.nlm.nih.gov/pubmed/31977076

https://ascpt.onlinelibrary.wiley.com/doi/abs/10.1002/cpt.1797

Cannabis use and outcomes after aneurysmal subarachnoid hemorrhage: A nationwide retrospective cohort study.

Posted on January 25, 2020 by David Worrell

Journal of Clinical Neuroscience Home “Cannabis is the most consumed recreational drug in the world.

It is possible that cannabis has an association with an increased risk of vasospasm-related strokes and delayed cerebral ischemia (DCI), which are major causes of morbidity and mortality in aneurysmal subarachnoid hemorrhage (aSAH). Hence, this study aimed to explore the independent relationship between cannabis use and outcomes after aSAH using the 2016 United States Nationwide Inpatient Sample.

RESULTS:

There were 42,394 patients identified with aSAH, of whom 925 were identified as cannabis users.

Cannabis users and non-users were similar in terms of severity of aSAH.

Although the unadjusted mortality rate was lower among cannabis users (16%) than non-users (22%), (p = 0.04), both the age-adjusted odds ratio (OR) (0.83, 95% confidence interval (CI): 0.56; 1.24) and the multivariate-adjusted OR (0.87, 95% CI: 0.54; 1.42) did not reach statistical significance.

Secondary outcomes did not reach statistical significance.

CONCLUSION:

In this nationwide cohort, cannabis users with aSAH had similar outcomes compared to nonusers. However, these results are likely limited by underreporting of cannabis use. Future prospective studies are needed to elucidate the pathophysiology and association between cannabis and outcomes following aSAH.”

https://www.ncbi.nlm.nih.gov/pubmed/31973920

https://www.jocn-journal.com/article/S0967-5868(19)31930-7/fulltext

The nephrologist’s guide to cannabis and cannabinoids.

Posted on January 25, 2020 by David Worrell

“Cannabis (marijuana, weed, pot, ganja, Mary Jane) is the most commonly used federally illicit drug in the United States.

The present review provides an overview of cannabis and cannabinoids with relevance to the practice of nephrology so that clinicians can best take care of patients.