Monthly Archives: August 2018

Optimization Of A Preclinical Therapy Of Cannabinoids In Combination With Temozolomide Against Glioma.

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 Biochemical Pharmacology “Glioblastoma multiforme (GBM) is the most frequent and aggressive form of brain cancer. These features are explained at least in part by the high resistance exhibited by these tumors to current anticancer therapies. Thus, the development of novel therapeutic approaches is urgently needed to improve the survival of the patients suffering this devastating disease.

Δ9-Tetrahydrocannabinol (THC, the major active ingredient of marijuana), and other cannabinoids have been shown to exert antitumoral actions in animal models of cancer, including glioma. The mechanism of these anticancer actions relies, at least in part, on the ability of these compounds to stimulate autophagy-mediated apoptosis in tumor cells.

Previous observations from our group demonstrated that local administration of THC (or of THC + CBD at a 1:1 ratio, a mixture that resembles the composition of the cannabinoid-based medicine Sativex®) in combination with Temozolomide, the benchmark agent for the treatment of GBM, synergistically reduces the growth of glioma xenografts.

With the aim of optimizing the possible clinical utilization of cannabinoids in anti-GBM therapies, in this work we explored the anticancer efficacy of the systemic administration of cannabinoids in combination with TMZ in preclinical models of glioma.

Our results show that oral administration of THC+CBD (Sativex-like extracts) in combination with TMZ produces a strong antitumoral effect in both subcutaneous and intracranial glioma cell-derived tumor xenografts. In contrast, combined administration of Sativex-like and BCNU (another alkylating agent used for the treatment of GBM which share structural similarities with the TMZ) did not show a stronger effect than individual treatments.

Altogether, our findings support the notion that the combined administration of TMZ and oral cannabinoids could be therapeutically exploited for the management of GBM.”

https://www.ncbi.nlm.nih.gov/pubmed/30125556

https://www.sciencedirect.com/science/article/abs/pii/S0006295218303496

Cannabidiol Attenuates Experimental Autoimmune Encephalomyelitis Model of Multiple Sclerosis Through Induction of Myeloid-Derived Suppressor Cells.

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“Multiple sclerosis (MS) is a chronic debilitating autoimmune disease without a cure. While the use of marijuana cannabinoids for MS has recently been approved in some countries, the precise mechanism of action leading to attenuate neuroinflammation is not clear. We used experimental autoimmune encephalomyelitis (EAE), a murine model of MS, to explore the anti-inflammatory properties of cannabidiol (CBD), a non-psychoactive cannabinoid. Treatment with CBD caused attenuation of EAE disease paradigms as indicated by a significant reduction in clinical scores of paralysis, decreased T cell infiltration in the central nervous system, and reduced levels of IL-17 and IFNγ. Interestingly, CBD treatment led to a profound increase in myeloid-derived suppressor cells (MDSCs) in EAE mice when compared to the vehicle-treated EAE controls. These MDSCs caused robust inhibition of MOG-induced proliferation of T cells in vitro. Moreover, adoptive transfer of CBD-induced MDSCs ameliorated EAE while MDSC depletion reversed the beneficial effects of CBD treatment, thereby conclusively demonstrating that MDSCs played a crucial role in CBD-mediated attenuation of EAE. Together, these studies demonstrate for the first time that CBD treatment may ameliorate EAE through induction of immunosuppressive MDSCs.”

https://www.ncbi.nlm.nih.gov/pubmed/30123217

“In conclusion, we have demonstrated that the mitigation of EAE with CBD comes from its ability to target a range of anti-inflammatory pathways, including (i) induction of anti-inflammatory MDSCs and (ii) decrease in pro-inflammatory and induction of anti-inflammatory cytokines. Because CBD is non-psychoactive, our studies suggest that CBD may constitute an excellent candidate for the treatment of MS and other autoimmune diseases. Our studies provide further evidence of the importance of MDSCs and that manipulation of such cells may constitute novel therapeutic modality to treat MS and other autoimmune diseases.”

https://www.frontiersin.org/articles/10.3389/fimmu.2018.01782/full

Dravet Syndrome: A Sodium Channel Interneuronopathy.

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Current Opinion in Physiology

“Dravet Syndrome is a devastating childhood epilepsy disorder with high incidence of premature death plus comorbidities of ataxia, circadian rhythm disorder, impaired sleep quality, autistic-like social-interaction deficits and severe cognitive impairment. It is primarily caused by heterozygous loss-of-function mutations in the SCN1A gene that encodes brain voltage-gated sodium channel type-1, termed NaV1.1. Here I review experiments on mouse genetic models that implicate specific loss of sodium currents and action potential firing in GABAergic inhibitory interneurons as the fundamental cause of Dravet Syndrome. The resulting imbalance of excitatory to inhibitory neurotransmission in neural circuits causes both epilepsy and co-morbidities. Promising therapeutic approaches involving atypical sodium channel blockers, novel drug combinations, and cannabidiol give hope for improved outcomes for Dravet Syndrome patients.”

https://www.ncbi.nlm.nih.gov/pubmed/30123852
https://www.sciencedirect.com/science/article/pii/S2468867317300305?via%3Dihub

Impact of substance use disorder on gray matter volume in schizophrenia.

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Psychiatry Research: Neuroimaging

“Substance use may confound the study of brain structure in schizophrenia. We used voxel-based morphometry (VBM) to examine whether differences in regional gray matter volumes exist between schizophrenia patients with (n = 92) and without (n = 66) clinically significant cannabis and/or alcohol use histories compared to 88 healthy control subjects.

Relative to controls, patients with schizophrenia had reduced gray matter volume in the bilateral precentral gyrus, right medial frontal cortex, right visual cortex, right occipital pole, right thalamus, bilateral amygdala, and bilateral cerebellum regardless of substance use history.

Within these regions, we found no volume differences between patients with schizophrenia and a history of cannabis and/or alcohol compared to patients with schizophrenia without a clinically significant substance use history.

Our data support the idea that a clinically meaningful history of alcohol or cannabis use does not significantly compound the gray matter deficits associated with schizophrenia.”

 https://www.ncbi.nlm.nih.gov/pubmed/30121336
https://www.sciencedirect.com/science/article/pii/S0925492718300040?via%3Dihub

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

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 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.

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 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

The novel peripherally active cannabinoid type 1 and serotonin type 3 receptor agonist AM9405 inhibits gastrointestinal motility and reduces abdominal pain in mouse models mimicking irritable bowel syndrome.

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European Journal of Pharmacology

“The endocannabinoid system (ECS) plays a crucial role in numerous physiological processes in the central and peripheral nervous systems. In the gastrointestinal (GI) tract, selective cannabinoid (CB) receptor agonists exert potent inhibitory actions on motility and pain signalling. In the present study, we used mouse models of diarrhea, hypermotility, and abdominal pain to examine whether a novel synthetic CB1 receptor agonist AM9405 [(2-(2,6-dihydroxy-4-(2-methyloctan-2-yl)phenyl)-1,3-dimethyl-1H-benzo[d]imidazol-3-ium bromide); also known as GAT379] exhibits effects of potential therapeutic relevance. AM9405 significantly slowed mouse intestinal motility in physiological conditions. Moreover, AM9405 reversed hypermotility and reduced pain in mouse models mimicking symptoms of functional GI disorders, such as stress-induced diarrhoea and writhing test. Interestingly, some of the effects of AM9405 were blocked by a 5-HT3 antagonist suggesting interaction with 5-HT3 receptors. In our study we show that combining CB1 agonism with 5-HT3 agonism may alter physiological functions and experimental pathophysiologies in a manner that make such compounds promising drugs for the future treatment of functional GI disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/30121173

https://www.sciencedirect.com/science/article/pii/S0014299918304734?via%3Dihub

Antimicrobial activity of Cannabis sativa, Thuja orientalis and Psidium guajava leaf extracts against methicillin-resistant Staphylococcus aureus.

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Journal of Integrative Medicine

“This study examined the antimicrobial activity of Cannabis sativa, Thuja orientalis and Psidium guajava against methicillin-resistant Staphylococcus aureus (MRSA) and used a standardized purification protocol to determine the presence and abundance of bioactive compounds in the leaf extracts.

RESULTS:

Resistance to methicillin, penicillin, oxacillin and cefoxitin was observed in each of the clinical and nonclinical MRSA isolates. However, they were still vulnerable to vancomycin. Used individually, the 50% extract of each plant leaf inhibited MRSA growth. A profound synergism was observed when C. sativa was used in combination with T. orientalis (1:1) and when P. guajava was used in combination with T. orientalis (1:1). This was shown by larger zones of inhibition. This synergism was probably due to the combined inhibitory effect of phenolics present in the leaf extracts (i.e., quercetin and gallic acid) and catechin, as detected by HPTLC.

CONCLUSION:

The leaf extracts of C. sativa, T. orientalis and P. guajava had potential for the control of both hospital- and community-acquired MRSA. Moreover, the inhibitory effect was enhanced when extracts were used in combination.”

https://www.ncbi.nlm.nih.gov/pubmed/30120078

https://www.sciencedirect.com/science/article/pii/S2095496418300815?via%3Dihub

New approaches and challenges to targeting the endocannabinoid system.

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“The endocannabinoid signalling system was discovered because receptors in this system are the targets of compounds present in psychotropic preparations of Cannabis sativa. The search for new therapeutics that target endocannabinoid signalling is both challenging and potentially rewarding, as endocannabinoids are implicated in numerous physiological and pathological processes. Hundreds of mediators chemically related to the endocannabinoids, often with similar metabolic pathways but different targets, have complicated the development of inhibitors of endocannabinoid metabolic enzymes but have also stimulated the rational design of multi-target drugs. Meanwhile, drugs based on botanical cannabinoids have come to the clinical forefront, synthetic agonists designed to bind cannabinoid receptor 1 with very high affinity have become a societal threat and the gut microbiome has been found to signal in part through the endocannabinoid network. The current development of drugs that alter endocannabinoid signalling and how this complex system could be pharmacologically manipulated in the future are described in this Opinion article.”

https://www.ncbi.nlm.nih.gov/pubmed/30116049
https://www.nature.com/articles/nrd.2018.115

Cannabinoid signalling in the immature brain: encephalopathies and neurodevelopmental disorders.

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Biochemical Pharmacology

“The endocannabinoid system exerts a crucial neuromodulatory role in many brain areas that is essential for proper regulation of neuronal activity. The role of cannabinoid signalling controlling neuronal activity in the adult brain is also evident when considering its contribution to adult brain insults or neurodegenerative diseases.

In the context of brain genetic or acquired encephalopathies administration of cannabinoid-based molecules has demonstrated to exert symptomatic relief and hence, they are proposed as new potential therapeutic compounds.

This review article summarizes the main evidences indicating the beneficial action of cannabinoid-derived molecules in preclinical models of neonatal hypoxia/ischemic damage. In a second part, we discuss the available evidences of therapeutic actions of cannabidiol in children with refractory epilepsy syndromes. Finally, we discuss the current view of cannabinoid signalling mechanisms active in the immature brain that affect in neural cell fate and can contribute to long-term neural cell plasticity.”

https://www.ncbi.nlm.nih.gov/pubmed/30118663

https://www.sciencedirect.com/science/article/abs/pii/S0006295218303344