Anti-allodynic and medullary modulatory effects of a single dose of delta-9-tetrahydrocannabinol (THC) in neuropathic rats tolerant to morphine

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“Neuropathic pain (NP) is often treated with opioids, the prolonged use of which causes tolerance to their analgesic effect and can potentially cause death by overdose. The phytocannabinoid delta-9-tetrahydrocannabinol (THC) may be an effective alternative analgesic to treat NP in morphine-tolerant subjects. Male Wistar rats developed NP after spared nerve injury, and were then treated with increasing doses of THC (1, 1.5, 2, 2.5, and 5 mg/kg, intraperitoneally) which reduced mechanical allodynia at the dose of 2.5 and 5 mg/kg. Another group of NP rats were treated with morphine (5 mg/kg, twice daily for 7 days, subcutaneously), until tolerance developed, and on day 8 received a single dose of THC (2.5 mg/kg), which significantly reduced mechanical allodynia. To evaluate the modulation of THC in the descending pain pathway, in vivo electrophysiological recordings of pronociceptive ON cells and antinociceptive OFF cells in the rostroventral medulla (RVM) were recorded after intra-PAG microinjection of THC (10 μg/μl). NP rats with morphine tolerance, compared to the control one, showed a tonic reduction of the spontaneous firing rate of ON cells by 44%, but the THC was able to further decrease it (a hallmark of many analgesic drugs acting at supraspinal level). On the other hand, the firing rate, of the antinociceptive OFF cells was increased after morphine tolerance by 133%, but the THC failed to further activate it. Altogether, these findings indicate that a single dose of THC produces antiallodynic effect in individuals with NP who are tolerant to morphine, acting mostly on the ON cells of the descending pain pathways, but not on OFF cells.”

The Cannabis sativa genetics and therapeutics relationship network: automatically associating cannabis-related genes to therapeutic properties through chemicals from cannabis literature

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“Background: Understanding the genome of Cannabis sativa holds significant scientific value due to the multi-faceted therapeutic nature of the plant. Links from cannabis gene to therapeutic property are important to establish gene targets for the optimization of specific therapeutic properties through selective breeding of cannabis strains. Our work establishes a resource for quickly obtaining a complete set of therapeutic properties and genes associated with any known cannabis chemical constituent, as well as relevant literature.

Methods: State-of-the-art natural language processing (NLP) was used to automatically extract information from many cannabis-related publications, thus producing an undirected multipartite weighted-edge paragraph co-occurrence relationship network composed of two relationship types, gene-chemical and chemical property. We also developed an interactive application to visualize sub-graphs of manageable size.

Results: Two hundred thirty-four cannabis constituent chemicals, 352 therapeutic properties, and 124 genes from the Cannabis sativa genome form a multipartite network graph which transforms 29,817 cannabis-related research documents from PubMed Central into an easy to visualize and explore network format.

Conclusion: Use of our network replaces time-consuming and labor intensive manual extraction of information from the large amount of available cannabis literature. This streamlined information retrieval process will enhance the activities of cannabis breeders, cannabis researchers, organic biochemists, pharmaceutical researchers and scientists in many other disciplines.”

Cannabinoids in Treating Parkinson’s Disease Symptoms: A Systematic Review of Clinical Studies

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“Background: Parkinson’s disease (PD) is a serious neurodegenerative condition impacting many individuals worldwide. There is a need for new non-invasive treatments of PD. Cannabinoids in the form of cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) may offer utility as treatment, and our objective was hence to conduct a systematic review regarding the clinical evidence for the efficacy and safety of cannabinoids in treating PD. 

Methods: Screening, data extraction, and quality assessments were all conducted by multiple reviewers, with discrepancies resolved by consensus. 

Results: After conducting searches in 4 different databases, 673 articles were screened. Thirteen articles were deemed eligible for inclusion in this review. It was shown that cannabis, CBD, and nabilone (a synthetic form of THC) were capable of consistently improving motor symptoms more than a placebo. All treatments improved various non-motor symptoms, particularly with cannabis improving pain intensity, and CBD improving psychiatric symptoms in a dose-dependent manner. Adverse effects were usually minor, and, in the case of CBD, rare (except at very high doses). 

Conclusion: Cannabinoids have been shown to safely offer important potential in treating motor symptoms in PD and some non-motor symptoms. More large-scale randomized control trials for specific forms of cannabinoid treatments are required to determine their overall efficacy.”

Antitumor Effects of Cannabis sativa Bioactive Compounds on Colorectal Carcinogenesis

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“Cannabis sativa is a multipurpose plant that has been used in medicine for centuries. Recently, considerable research has focused on the bioactive compounds of this plant, particularly cannabinoids and terpenes. Among other properties, these compounds exhibit antitumor effects in several cancer types, including colorectal cancer (CRC). Cannabinoids show positive effects in the treatment of CRC by inducing apoptosis, proliferation, metastasis, inflammation, angiogenesis, oxidative stress, and autophagy. Terpenes, such as β-caryophyllene, limonene, and myrcene, have also been reported to have potential antitumor effects on CRC through the induction of apoptosis, the inhibition of cell proliferation, and angiogenesis. In addition, synergy effects between cannabinoids and terpenes are believed to be important factors in the treatment of CRC. This review focuses on the current knowledge about the potential of cannabinoids and terpenoids from C. sativa to serve as bioactive agents for the treatment of CRC while evidencing the need for further research to fully elucidate the mechanisms of action and the safety of these compounds.”

“Data suggest that cannabinoids exert advantages in the treatment of CRC, mostly by inducing apoptosis, although some evidence also points out that they may target other key therapeutic events, such as proliferation, metastasis, inflammation, angiogenesis, oxidative stress, and autophagy. The currently available data on this subject refer mostly to the C. sativa major cannabinoids, i.e., CBD, THC, and CBG, but several pieces of evidence suggest that minor cannabinoids and other bioactive compounds such as terpenes also may hold potential as therapeutic agents for CRC. Data also suggest that certain combinations of cannabinoids and terpenes in C. sativa extracts can lead to a synergistic action known as the “entourage effect,” which has been linked to certain pharmacological benefits. The potential therapeutic benefits of the cannabinoids and terpenes from this plant make them key candidates for further drug development.”

Cannabinoids Reduce Melanoma Cell Viability and Do Not Interfere with Commonly Used Targeted Therapy in Metastatic Melanoma In Vivo and In Vitro

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“Background: Cannabinoids are mainly used for recreational purposes, but also made their way into oncology, since these substances can be taken to increase appetite in tumour cachexia. Since there are some hints in the literature that cannabinoids might have some anti-cancerous effects, the aim of this study was to study if and how cannabinoids mediate pro-apoptotic effects in metastatic melanoma in vivo and in vitro and its value besides conventional targeted therapy in vivo. 

Methods: Several melanoma cell lines were treated with different concentrations of cannabinoids, and anti-cancerous efficacy was assessed by proliferation and apoptosis assays. Subsequent pathway analysis was performed using apoptosis, proliferation, flow cytometry and confocal microscopy data. The efficacy of cannabinoids in combination with trametinib was studied in NSG mice in vivo. 

Results: Cannabinoids reduced cell viability in multiple melanoma cell lines in a dose-dependent way. The effect was mediated by CB1, TRPV1 and PPARα receptors, whereby pharmacological blockade of all three receptors protected from cannabinoid-induced apoptosis. Cannabinoids initiated apoptosis by mitochondrial cytochrome c release with consecutive activation of different caspases. Essentially, cannabinoids significantly decreased tumour growth in vivo and were as potent as the MEK inhibitor trametinib. 

Conclusions: We could demonstrate that cannabinoids reduce cell viability in several melanoma cell lines, initiate apoptosis via the intrinsic apoptotic pathway by cytochrome c release and caspase activation and do not interfere with commonly used targeted therapy.”

“Cannabinoids are mainly used for recreational purposes but find their way into oncology due to ongoing legalization efforts and anti-cancerous hints in the scientific literature. The goal of this study was to elucidate the mode of action of a clinically used cannabis medication in metastatic melanoma as well as its clinical value in combination with targeted therapy. By cell viability and apoptosis assays, we could demonstrate that cannabinoids mediate their apoptotic effect in a caspase-mediated fashion by disturbing mitochondrial integrity. With in vivo experiments, we could demonstrate that clinically used cannabinoid medication does not interfere with the commonly used anti-cancerous drug trametinib. Our results suggest that cannabinoids are effective in metastatic melanoma and pave the way for further clinical trials.”

Analgesia by intrathecal delta-9-tetrahydrocannabinol is dependent on Cav3.2 calcium channels

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“Delta-9-tetrahydrocannabinol (Δ9-THC) is known to produce systemic analgesia that involves CB1 and CB2 cannabinoid receptors. However, there is compelling evidence that Δ9-THC can potently inhibit Cav3.2T-type calcium channels which are highly expressed in dorsal root ganglion neurons and in the dorsal horn of the spinal cord. Here, we investigated whether spinal analgesia produced by Δ9-THC involves Cav3.2 channels vis a vis cannabinoid receptors. We show that spinally delivered Δ9-THC produced dose-dependent and long-lasting mechanical anti-hyperalgesia in neuropathic mice, and showed potent analgesic effects in models of inflammatory pain induced by formalin or Complete Freund’s Adjuvant (CFA) injection into the hind paw, with the latter showing no overt sex differences. The Δ9-THC mediated reversal of thermal hyperalgesia in the CFA model was abolished in Cav3.2 null mice, but was unaltered in CB1 and CB2 null animals. Hence, the analgesic effects of spinally delivered Δ9-THC are due to an action on T-type calcium channels, rather than activation of spinal cannabinoid receptors.”

Therapeutic use of cannabinoids for the treatment of neurodegenerative disorders: a potential breakthrough

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“Marijuana, also known as cannabis, is a plant-based illicit drug notorious for its recreational purposes. However, in recent years its extracts are being extensively studied for their overall therapeutic effects. Active substances found in marijuana that interact with the endocannabinoid system are known as cannabinoids, the primary examples being 9-tetrahydrocannabinol (9-THC) and Cannabidiol (CBD). These cannabinoids ligand to receptors such as CB1 (found in CNS) and CB2 (found in immune system cells) to prevent the release of neurotransmitters and modulate immune cell migration as well as cytokine release, respectively (1). In recent years, there has been a surge of interest in the neuroprotective potential of marijuana; however, investigators could not make firm conclusions about the effectiveness of these treatments. A comprehensive review by Bahji A et al. (2022) found an evident link between cannabidiol-based products and relief from the motor as well as behavioural and psychological symptoms spanning Alzheimer’s disease (AD), Huntington’s disease (HD), and Parkinson’s disease (PD) (2). Here we discuss the effects of marijuana and its derivatives on the treating significant neurodegenerative disorders.

Dronabinol (2.5 mg) seemed to lessen the disordered behaviours as assessed by the Cohen-Mansfield Agitation Inventory in 12 patients of AD (p=0.05) (3). Sherman et al. (2018) reported the association of cannabis administration with weight and pain management in AD patients. The adverse effects are typically well tolerated at the levels supplied, even though cannabis is linked to an increased risk of euphoria, sleepiness and psychosis (1). On the other hand, for HD, nabilone (1 or 2 mg) had a substantial therapeutic benefit in a different 10-week placebo-controlled crossover experiment as determined by the overall motor and chorea score on the Unified Huntington’s Disease Rating Scale (UHDRS) (4). Available reviews revealed variable evidence suggesting the clinical benefits of cannabis in treating motor symptoms in patients with PD. A randomized trial found that compared to a placebo, giving a single dosage of 300 mg of CBD successfully decreased tremor amplitude (5).

Neurological diseases, including  the  neurodegenerative diseases,  comprise  8.7% of the disease burden  in lower- middle- income countries (such as Pakistan) (6). Currently, there is no real cure for neurodegenerative disorders, only symptomatic management, such as dopamine treatment for PD or cholinesterase inhibitors for dementia. Cannabinoids might be the lifeline all neurodegenerative disorder patients have been waiting for.”

Long-term safety of medical cannabis in Parkinson’s disease: A retrospective case-control study

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“Background: Whole-plant medical cannabis (MC) products are widely used for controlling symptoms associated with Parkinson’s disease (PD). Despite its widespread use, few studies have investigated the long-term impact of MC on the progression of PD or its safety profile. This study examined the effects of MC on PD in a real-life setting.

Methods: A retrospective case-control study of 152 idiopathic PD patients (mean age 69.1 ± 9.0 years), followed at the Sheba Medical Center Movement Disorders Institute (SMDI) from 2008 to 2022 was conducted. Seventy-six patients who used licensed whole-plant medical cannabis (MC) for at least a year were compared to a matched group who did not receive MC in terms of their Levodopa Equivalent Daily Dose (LEDD), Hoehn and Yahr (H&Y) stage, and cognitive, depressive, and psychotic symptoms.

Results: The median monthly dose of MC was 20 g (IQR: 20-30), with a median Tetrahydrocannabinol (THC) percentage of 10 (IQR: 9.5-14.15) and a median Cannabidiol (CBD) percentage of 4 (IQR: 2-10). There were no significant differences between the MC and the control groups for LEDD or H&Y stage progression (p = 0.90, 0.77, respectively). A Kaplan-Meier analysis showed no evidence of relative worsening of psychotic, depressive, or cognitive symptoms reported by patients to their treating physicians over time in the MC group (p = 0.16-0.50).

Conclusion: Over the 1-3 years of follow-ups, the MC treatment regimens appeared to be safe. MC did not exacerbate neuropsychiatric symptoms and had no detrimental effects on disease progression.”

Cannabis Pharmacogenomics: A Path to Personalized Medicine

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“Cannabis and related compounds have created significant research interest as a promising therapy in many disorders. However, the individual therapeutic effects of cannabinoids and the incidence of side effects are still difficult to determine. Pharmacogenomics may provide the answers to many questions and concerns regarding the cannabis/cannabinoid treatment and help us to understand the variability in individual responses and associated risks. Pharmacogenomics research has made meaningful progress in identifying genetic variations that play a critical role in interpatient variability in response to cannabis. This review classifies the current knowledge of pharmacogenomics associated with medical marijuana and related compounds and can assist in improving the outcomes of cannabinoid therapy and to minimize the adverse effects of cannabis use. Specific examples of pharmacogenomics informing pharmacotherapy as a path to personalized medicine are discussed.”

Personalized medicine could transform healthcare”

Medical Cannabis in the Treatment of Parkinson’s Disease

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“Objectives: Medical cannabis (MC) has recently garnered interest as a potential treatment for neurologic diseases, including Parkinson’s disease (PD). A retrospective chart review was conducted to explore the impact of MC on the symptomatic treatment of patients with PD.

Methods: Patients with PD treated with MC in the normal course of clinical practice were included (n = 69). Data collected from patient charts included MC ratio/formulation changes, PD symptom changes after initiation of MC, and adverse events (AEs) from MC use. Information regarding changes in concomitant medications after MC initiation, including opioids, benzodiazepines, muscle relaxants, and PD medications, was also collected.

Results: Most patients were initially certified for a 1:1 (∆ 9 -tetrahydrocannabinol:cannabidiol) tincture. Eight-seven percent of patients (n = 60) were noted to exhibit an improvement in any PD symptom after starting MC. Symptoms with the highest incidence of improvement included cramping/dystonia, pain, spasticity, lack of appetite, dyskinesia, and tremor. After starting MC, 56% of opioid users (n = 14) were able to decrease or discontinue opioid use with an average daily morphine milligram equivalent change from 31 at baseline to 22 at the last follow-up visit. The MC was well-tolerated with no severe AEs reported and low rate of MC discontinuation due to AEs (n = 4).

Conclusions: The MC may improve motor and nonmotor symptoms in patients with PD and may allow for reduction of concomitant opioid medication use. Large, placebo-controlled, randomized studies of MC use in patients with PD are required.”