Cannabis in liver disorders: a friend or a foe?

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“The recent legalization of recreational marijuana use in some parts of the world, the discovery of new indications for the clinical application of cannabis, and the acceptance of the use of cannabis in practice has been paralleled by extensive research on the active components of cannabis and the endocannabinoid system within the human body.

In this review, we evaluate the available evidence on cannabis and its constituents and the application of this evidence in clinical practice, focusing particularly on the liver and liver diseases.

Constituents of cannabis, such as cannabidiol and Δ-tetrahydrocannabinol, have shown anti-inflammatory, antioxidant, and hepatoprotective effects both in in vitro and clinical studies, and appear to have potential in the symptom management and treatment of various liver diseases that were previously considered difficult to manage conservatively.

In addition, the manipulation of the inherent endocannabinoid response system has found favor in many clinical fields and has generated considerable research and clinical interest. Moreover, evidence with regard to the adverse effects of marijuana use in liver diseases is weak, which has led to raise a question on the prior rules, with regard to a denial of liver transplantation to marijuana users.

All in all, the recent trends in research, clinical experiences, as well as the legislature, has opened up new avenues towards the widespread clinical application of cannabis and its derivatives as well as modifiers of the components of the endocannabinoid system. More research is required to fully exploit these new evidences.”

https://www.ncbi.nlm.nih.gov/pubmed/30169449

https://insights.ovid.com/crossref?an=00042737-900000000-97980

Δ9-tetrahydrocannabivarin impairs epithelial calcium transport through inhibition of TRPV5 and TRPV6.

 Pharmacological Research

“Compounds extracted from the cannabis plant, including the psychoactive Δ9-tetrahydrocannabinol (THC) and related phytocannabinoids, evoke multiple diverse biological actions as ligands of the G protein-coupled cannabinoid receptors CB1 and CB2. In addition, there is increasing evidence that phytocannabinoids also have non-CB targets, including several ion channels of the transient receptor potential superfamily.

We investigated the effects of six non-THC phytocannabinoids on the epithelial calcium channels TRPV5 and TRPV6, and found that one of them, Δ9-tetrahydrocannabivarin (THCV), exerted a strong and concentration-dependent inhibitory effect on mammalian TRPV5 and TRPV6 and on the single zebrafish orthologue drTRPV5/6. Moreover, THCV attenuated the drTRPV5/6-dependent ossification in zebrafish embryos in vivo. Oppositely, 11-hydroxy-THCV (THCV-OH), a product of THCV metabolism in mammals, stimulated drTRPV5/6-mediated Ca2+ uptake and ossification.

These results identify the epithelial calcium channels TRPV5 and TRPV6 as novel targets of phytocannabinoids, and suggest that THCV-containing products may modulate TRPV5- and TRPV6-dependent epithelial calcium transport.”

https://www.ncbi.nlm.nih.gov/pubmed/30170189

https://linkinghub.elsevier.com/retrieve/pii/S1043661818311095

Effects of feeding a source of omega-3 fatty acid during the early postpartum period on the endocannabinoid system in the bovine endometrium.

Theriogenology

“A total of sixteen Holstein dairy cows (35 ± 1.1 kg/d of milk yield) were randomly assigned to consider the effects of feeding omega-3 sources on endometrial endocannabinoids system (ECS) genes expression to understand the effect mechanism of omega-3 on reproductive performances during the early postpartum period to evaluate to what extent can be intervened in reproduction, e.g. via nutrition to improve fertility. Experimental diets were 1) either protected palm oil (control) or 2) extruded linseed (linseed). Cows (n = 16) were fed from calving date to 70 days in milk (DIM). There was no difference between groups (mean ± S.E.M.) in parity (3.0 ± 1.00) or body condition score (BCS) at calving day (3.1 ± 0.25). At 30 DIM, the ovulatory cycles of cows were synchronized using two injections of prostaglandin F2α (PGF2α) with a 14-day interval. On day 15 of synchronized estrous cycle (d0 = ovulation) uterine endometrial biopsies were collected to evaluate the expression of genes related to ECS (endocannabinoid receptor (CNR2), N-acyl phosphatidylethanolamine phospholipase D (NAPEPLD), fatty acid amide hydrolase (FAAH), N-acylethanolamine acid amidase (NAAA), monoglyceride lipase (MGLL)) and PGF2α. Results showed that dry matter intake and milk yield were not affected by diets. Uterine endometrial NAAA (7.69 fold), and MGLL (1.96 fold) genes expression were greater (P < 0.05) in cows fed linseed compared with control ones. The messenger RNA (mRNA) levels of CNR-2 (4.26 fold), and NAPEPLD (20.0 fold) were decreased (P < 0.05) in animals fed linseed compared to control cows. The expression of mRNA for the FAAH was not influenced by the diets. First service conception rate was greater in cows fed linseed compared to control cows (75 vs. 25%). Pregnancy loss within 32-60 day after artificial insemination (AI) was lower in cows fed linseed compared to control cows (0 vs. 100%). In conclusion these data demonstrated that positive effect of omega-3 on reproduction may act through a mechanism involving the ECS. However, more studies to be undertaken to confirm these results.”

Targeting the Endocannabinoid System for Prevention or Treatment of Chemotherapy-Induced Neuropathic Pain: Studies in Animal Models.

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“There is a scarcity of drugs to either prevent or properly manage chemotherapy-induced neuropathic pain (CINP). Cannabis or cannabinoids have been reported to improve pain measures in patients with neuropathic pain.

For this review, a search was done in PubMed for papers that examined the expression of and/or evaluated the use of cannabinoids or drugs that prevent or treat established CINP in a CB receptor-dependent manner in animal models.

Studies suggest there is a specific deficiency of endocannabinoids in the periphery during CINP.

Inhibitors of FAAH and MGL, enzymes that degrade the endocannabinoids, CB receptor agonists, desipramine, and coadministered indomethacin plus minocycline were found to either prevent the development and/or attenuate established CINP in a CB receptor-dependent manner.

The studies analysed suggest that targeting the endocannabinoid system for prevention and treatment of CINP is a plausible therapeutic option. Almost 90% of the studies on animal models of CINP analysed utilised male rodents. Taking into consideration clinical and experimental findings that show gender differences in the mechanisms involved in pain including CINP and in response to analgesics, it is imperative that future studies on CINP utilise more female models.”

“Cannabis or cannabinoids have been reported to improve pain measures in patients with neuropathic or cancer pain. The studies analysed suggest that targeting the endocannabinoid system for prevention and treatment of CINP is a plausible therapeutic option.” https://www.hindawi.com/journals/prm/2018/5234943/

A Brief Background on Cannabis: From Plant to Medical Indications.

 Ingenta Connect

“Cannabis has been used as a medicinal plant for thousands of years.

As a result of centuries of breeding and selection, there are now over 700 varieties of cannabis that contain hundreds of compounds, including cannabinoids and terpenes.

Cannabinoids are fatty compounds that are the main biological active constituents of cannabis. Terpenes are volatile compounds that occur in many plants and have distinct odors.

Cannabinoids exert their effect on the body by binding to receptors, specifically cannabinoid receptors types 1 and 2. These receptors, together with endogenous cannabinoids and the systems for synthesis, transport, and degradation, are called the Endocannabinoid System.

The two most prevalent and commonly known cannabinoids in the cannabis plant are delta-9-tetrahydrocannabinol (THC) and cannabidiol.

The speed, strength, and type of effects of cannabis vary based on the route of administration. THC is rapidly distributed through the body to fatty tissues like the brain and is metabolized by the cytochrome P450 system to 11-hydroxy-THC, which is also psychoactive.

Cannabis and cannabinoids have been indicated for several medical conditions.

There is evidence of efficacy in the symptomatic treatment of nausea and vomiting, pain, insomnia, post-traumatic stress disorder, anxiety, loss of appetite, Tourette’s syndrome, and epilepsy. Cannabis has also been associated with treatment for glaucoma, Huntington’s Disease, Parkinson’s Disease, and dystonia, but there is not good evidence to support its efficacy. Side effects of cannabis include psychosis and anxiety, which can be severe.

Here, we provided a summary of the history of cannabis, its pharmacology, and its medical uses.”

https://www.ncbi.nlm.nih.gov/pubmed/30139415

Cannabinoids in dermatology: a scoping review.

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“The therapeutic applications of cannabis and cannabinoids are an increasingly conspicuous topic as de-criminalization and legalization of these products continues to expand.

A limited number of cannabinoid compounds have been approved for a specific set of conditions. However, the current role of cannabinoids for the treatment of dermatologic conditions remains to be defined.

We conducted a review of the current literature to determine the applications of cannabinoids for the therapy of various skin diseases.

After conducting our analysis, we found that cannabinoid products have the potential to treat a variety of skin conditions, including acne vulgaris, allergic contact dermatitis, asteatotic dermatitis, atopic dermatitis, hidradenitis suppurativa, Kaposi sarcoma, pruritus, psoriasis, skin cancer, and the cutaneous manifestations of systemic sclerosis. However, the majority of available data on these compounds are pre-clinical and there is a corresponding lack of high-quality randomized, controlled trials that evaluate their effects.

Cannabinoids have shown some initial promise as therapy for a variety of skin diseases. However, there is a requirement for thorough pre-clinical research and large-scale, randomized, controlled trials before cannabinoids can be considered safe and effective treatments for these conditions.”

“The endocannabinoid system of the skin. A potential approach for the treatment of skin disorders”  https://www.sciencedirect.com/science/article/abs/pii/S0006295218303484

The endocannabinoid system of the skin. A potential approach for the treatment of skin disorders.

Biochemical Pharmacology

“The skin is the largest organ of the body and has a complex and very active structure that contributes to homeostasis and provides the first line defense against injury and infection.

In the past few years it has become evident that the endocannabinoid system (ECS) plays a relevant role in healthy and diseased skin.

Specifically, we review how the dysregulation of ECS has been associated to dermatological disorders such as atopic dermatitis, psoriasis, scleroderma and skin cancer. Therefore, the druggability of the ECS could open new research avenues for the treatment of the pathologies mentioned.

Numerous studies have reported that phytocannabinoids and their biological analogues modulate a complex network pharmacology involved in the modulation of ECS, focusing on classical cannabinoid receptors, transient receptor potential channels (TRPs), and peroxisome proliferator-activated receptors (PPARs).

The combined targeting of several end-points seems critical to provide better chances of therapeutically success, in sharp contrast to the one-disease-one-target dogma that permeates current drug discovery campaigns.”

https://www.ncbi.nlm.nih.gov/pubmed/30138623

https://www.sciencedirect.com/science/article/abs/pii/S0006295218303484

Cannabinoids and reduced risk of hepatic steatosis in HIV-HCV co-infection: paving the way for future clinical research

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“Whether or not cannabis itself or cannabinoids contained in it may help to reduce hepatic steatosis in HIV-HCV coinfected patients remains an open question. The existing body of knowledge on the interactions between cannabis and the liver suggest a protective effect of cannabinoids on insulin resistance, diabetes, and NAFLD in the general population. Clinical research with randomized study designs is needed to evaluate the efficacy and safety of cannabis-based pharmacotherapies in HIV-HCV coinfected patients. Targeting the endocannabinoid system seems essential to differently manage several pathological conditions such as intestinal inflammation, obesity, diabetes and fatty liver disease. However, to date, few drugs have been tested in clinical trials. CB1-antagonists and CB2 agonists appear to be viable therapeutic options that need to be explored for the management of liver diseases. As HCV cure rates are coming close to 100% in the era of direct-acting antivirals, it is especially important to be able to identify modifiable risk factors of complications and death in HIV-HCV coinfected patients, as well as possible levers for intervention. Given the persistence of metabolic risk factors after HCV eradication, cannabis-based therapies need to be evaluated both as preventive and therapeutic tools in patients living with or at risk of liver steatosis, possibly in combination with existing conventional approaches.”

https://www.tandfonline.com/doi/full/10.1080/14787210.2018.1473764

Cannabinoid pharmacology/therapeutics in chronic degenerative disorders affecting the central nervous system.

 Biochemical Pharmacology “The endocannabinoid system (ECS) exerts a modulatory effect of important functions such as neurotransmission, glial activation, oxidative stress, or protein homeostasis.

Dysregulation of these cellular processes is a common neuropathological hallmark in aging and in neurodegenerative diseases of the central nervous system (CNS). The broad spectrum of actions of cannabinoids allows targeting different aspects of these multifactorial diseases.

In this review, we examine the therapeutic potential of the ECS for the treatment of chronic neurodegenerative diseases of the CNS focusing on Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and amyotrophic lateral sclerosis.

First, we describe the localization of the molecular components of the ECS and how they are altered under neurodegenerative conditions, either contributing to or protecting cells from degeneration.

Second, we address recent advances in the modulation of the ECS using experimental models through different strategies including the direct targeting of cannabinoid receptors with agonists or antagonists, increasing the endocannabinoid tone by the inhibition of endocannabinoid hydrolysis, and activation of cannabinoid receptor-independent effects.

Preclinical evidence indicates that cannabinoid pharmacology is complex but supports the therapeutic potential of targeting the ECS.

Third, we review the clinical evidence and discuss the future perspectives on how to bridge human and animal studies to develop cannabinoid-based therapies for each neurodegenerative disorder.

Finally, we summarize the most relevant opportunities of cannabinoid pharmacology related to each disease and the multiple unexplored pathways in cannabinoid pharmacology that could be useful for the treatment of neurodegenerative diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/30121249

https://www.sciencedirect.com/science/article/abs/pii/S000629521830337X

Revisiting cannabinoid receptor 2 expression and function in murine retina.

 Neuropharmacology

“The cannabinoid receptor CB2 plays a significant role in the regulation of immune function whereas neuronal expression remains a subject of contention. Multiple studies have described CB2 in retina and a recent study showed that CB2 deletion altered retinal visual processing. We revisited CB2 expression using immunohistochemistry and a recently developed CB2-eGFP reporter mouse. We examined the consequence of acute vs. prolonged CB2 deactivation on the electroretinogram (ERG) responses. We also examined lipidomics in CB2 knockout mice and potential changes in microglia using Scholl analysis. Consistent with a published report, in CB2 receptor knockout mice see an increased ERG scotopic a-wave, as well as stronger responses in dark adapted cone-driven ON bipolar cells and, to a lesser extent cone-driven ON bipolar cells early in light adaptation. Significantly, however, acute block with CB2 antagonist, AM630, did not mimic the results observed in the CB2 knockout mice whereas chronic (7 days) block did. Immunohistochemical studies show no CB2 in retina under non-pathological conditions, even with published antibodies. Retinal CB2-eGFP reporter signal is minimal under baseline conditions but upregulated by intraocular injection of either LPS or carrageenan. CB2 knockout mice see modest declines in a broad spectrum of cannabinoid-related lipids. The numbers and morphology of microglia were unaltered. In summary minimal CB2 expression is seen in healthy retina. CB2 appears to be upregulated under pathological conditions. Previously reported functional consequences of CB2 deletion are an adaptive response to prolonged blockade of these receptors. CB2 therefore impacts retinal signaling but perhaps in an indirect, potentially extra-ocular fashion.”

https://www.ncbi.nlm.nih.gov/pubmed/30121200

https://www.sciencedirect.com/science/article/pii/S0028390818304775?via%3Dihub