Tag Archives: cannabinoid receptors

A Review of the Therapeutic Antitumor Potential of Cannabinoids.

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:Image result for J Altern Complement Med.

“The aim of this review is to discuss cannabinoids from a preclinical and clinical oncological perspective and provide the audience with a concise, retrospective overview of the most significant findings concerning the potential use of cannabinoids in cancer treatment.

RESULTS:

Cannabis sativa is a plant rich in more than 100 types of cannabinoids. Besides exogenous plant cannabinoids, mammalian endocannabinoids and synthetic cannabinoid analogues have been identified. Cannabinoid receptors type 1 (CB1) and type 2 (CB2) have been isolated and characterized from mammalian cells. Through cannabinoid receptor and non-receptor signaling pathways, cannabinoids show specific cytotoxicity against tumor cells, while protecting healthy tissue from apoptosis. The dual antiproliferative and proapoptotic effects of cannabinoids and associated signaling pathways have been investigated on a large panel of cancer cell lines. Cannabinoids also display potent anticancer activity against tumor xenografts, including tumors that express high resistance to standard chemotherapeutics. Few studies have investigated the possible synergistic effects of cannabinoids with standard oncology therapies, and are based on the preclinically confirmed concept of “cannabinoid sensitizers.” Also, clinical trials aimed to confirm the antineoplastic activity of cannabinoids have only been evaluated on a small number of subjects, with no consensus conclusions regarding their effectiveness.

CONCLUSIONS:

A large number of cannabinoid compounds have been discovered, developed, and used to study the effects of cannabinoids on cancers in model systems. However, few clinical trials have been conducted on the use of cannabinoids in the treatment of cancers in humans. Further studies require extensive monitoring of the effects of cannabinoids alone or in combination with standard anticancer strategies. With such knowledge, cannabinoids could become a therapy of choice in contemporary oncology.”

 https://www.ncbi.nlm.nih.gov/pubmed/28799775

Neuroprotective activity of cannabinoid receptor-2 against oxidative stress and apoptosis in rat pups having experimentally-induced congenital hypothyroidism.

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“In this study, it was aimed to show the cannabinoid receptor-2 (CB2) role, which is a part of neuroprotective endocannabinoidal system, against increasing nitric oxide synthetase (iNOS, eNOS) levels and the apoptotic activity (caspase-3, caspase-9 and DNA in situ fragmentation) within the postnatal critical period in pups of pregnant rats with artificially induced maternal thyroid hormone (TH) deficiency.

In conclusion, apoptosis was triggered via oxidative stress in hypothyroid pups. Accordingly, neuroprotective activity of CB2 receptors were motivated spontaneously to resist to CNS lesions during the first 3 weeks of postnatal period.”

https://www.ncbi.nlm.nih.gov/pubmed/28799288

Modulation of Astrocyte Activity by Cannabidiol, a Nonpsychoactive Cannabinoid.

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“The astrocytes have gained in recent decades an enormous interest as a potential target for neurotherapies, due to their essential and pleiotropic roles in brain physiology and pathology. Their precise regulation is still far from understood, although several candidate molecules/systems arise as promising targets for astrocyte-mediated neuroregulation and/or neuroprotection.

The cannabinoid system and its ligands have been shown to interact and affect activities of astrocytes. Cannabidiol (CBD) is the main non-psychotomimetic cannabinoid derived from Cannabis. CBD is devoid of direct CB1 and CB2 receptor activity, but exerts a number of important effects in the brain. Here, we attempt to sum up the current findings on the effects of CBD on astrocyte activity, and in this way on central nervous system (CNS) functions, across various tested models and neuropathologies.

The collected data shows that increased astrocyte activity is suppressed in the presence of CBD in models of ischemia, Alzheimer-like and Multiple-Sclerosis-like neurodegenerations, sciatic nerve injury, epilepsy, and schizophrenia. Moreover, CBD has been shown to decrease proinflammatory functions and signaling in astrocytes.”

https://www.ncbi.nlm.nih.gov/pubmed/28788104

http://www.mdpi.com/1422-0067/18/8/1669

Cannabinoid receptor 2-63 RR variant is independently associated with severe necroinflammation in HIV/HCV coinfected patients.

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“This is the first study to analyze the impact of the rs35761398 variant of the CNR2 gene leading to the substitution of GLN (Q) of codon 63 of the cannabinoid receptor 2 (CB2) with ARG (R) on the clinical presentation of chronic hepatitis in HIV/HCV coinfected patients.

This study shows interesting interplay between the CB2-RR variant and liver necroinflammation in chronic hepatitis patients with HIV/HCV coinfection, an observation of clinical value that coincides with the interest in the use of the CB2 agonists and antagonists in clinical practice emerging from the literature.”

 https://www.ncbi.nlm.nih.gov/pubmed/28759568
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0181890

Could Cannabidiol be a Treatment Option for Intractable Childhood and Adolescent Epilepsy?

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 “Epilepsy is an important disease that affects brain function, particularly in those under 3 years old. Uncontrolled seizures can affect cognitive function and quality of life. For these reasons, many trials have been conducted to investigate treatments for pediatric epilepsy. Currently, many antiepileptic drugs are available for the treatment of epilepsy, but cases of intractable epilepsy continue to exist.

In the past, cannabis has been tested as a potential treatment of intractable epilepsy.

Since 2013, 10 epilepsy centers in America have conducted research regarding the efficacy of cannabis to treat epilepsy. Cannabis has many components, including cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). THC has psychoactive properties exerted through its binding of the cannabinoid receptor (CBR) whereas CBD is a CBR antagonist. The inhibition of epilepsy by CBD may therefore be caused by various mechanisms, although the detailed mechanisms of CBD actions have not yet been well defined. In most studies, trial doses of CBD were 2-5 mg/kg/day.

Several such studies have shown that CBD does have efficacy for treatment of epilepsy.

Reported adverse effects of CBD were mostly mild, including drowsiness, diarrhea, and decreased appetite. Severe adverse reactions requiring treatment, such as status epilepticus, have also been reported but it is not clear that this is related to CBD. Furthermore, many previous studies have been limited by an open-label or survey design. In future, double-blind, controlled trials are required and the use of CBD to treat other neurological problems should also be investigated.”  https://www.ncbi.nlm.nih.gov/pubmed/28775950

“Most studies suggest anticonvulsant effects of CBD, and consider most adverse effects to be mild. It must be borne in mind that CBD is still illegal in many contexts. However, it has the potential to treat various neurological problems, including epilepsy.” http://www.j-epilepsy.org/journal/view.php?doi=10.14581/jer.17003

Combined deficiency of the Cnr1 and Cnr2 receptors protects against age-related bone loss by osteoclast inhibition.

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Aging Cell

“The endocannabinoid system plays a role in regulating bone mass and bone cell activity and inactivation of the type 1 (Cnr1) or type 2 (Cnr2) cannabinoid receptors influences peak bone mass and age-related bone loss. As the Cnr1 and Cnr2 receptors have limited homology and are activated by different ligands, we have evaluated the effects of combined deficiency of Cnr1 and 2 receptors (Cnr1/2-/- ) on bone development from birth to old age and studied ovariectomy induced bone loss in female mice. The Cnr1/2-/- mice had accelerated bone accrual at birth when compared with wild type littermates, and by 3 months of age, they had higher trabecular bone mass. They were also significantly protected against ovariectomy-induced bone loss due to a reduction in osteoclast number. The Cnr1/2-/- mice had reduced age-related bone loss when compared with wild-type due to a reduction in osteoclast number. Although bone formation was reduced and bone marrow adiposity increased in Cnr1/2-/- mice, the osteoclast defect outweighed the reduction in bone formation causing preservation of bone mass with aging. This contrasts with the situation previously reported in mice with inactivation of the Cnr1 or Cnr2 receptors individually where aged-related bone loss was greater than in wild-type. We conclude that the Cnr1 and Cnr2 receptors have overlapping but nonredundant roles in regulating osteoclast and osteoblast activities. These observations indicate that combined inhibition of Cnr1 and Cnr2 receptors may be beneficial in preventing age-related bone loss, whereas blockade of individual receptors may be detrimental.”

https://www.ncbi.nlm.nih.gov/pubmed/28752643

http://onlinelibrary.wiley.com/doi/10.1111/acel.12638/abstract

The endocannabinoid system expression in the female reproductive tract is modulated by estrogen.

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“The endocannabinoid system (ECS) is involved in several physiological events that resulted in a growing interest in its modulation. Moreover, the uterine levels of anandamide (AEA), the major endocannabinoid, must be tightly regulated to create proper embryo implantation conditions. However, there are no evidences about the regulation of AEA in uterus by estrogen.

Thus, the aim of this study is to elucidate whether estradiol benzoate (EB) and tamoxifen (TAM) administration to ovariectomized (OVX) rats can induce changes in the expression of cannabinoid receptors and AEA-metabolic enzymes in uterus by evaluating gene transcription and protein levels by qPCR, Western blot and immunohistochemistry.

In summary, these data collectively indicate that the expression of ECS components, as well as, the AEA and PGE2 levels in rat uterus is modulated by EB. Thus, estradiol may have a direct regulatory role in the modulation of ECS in female reproductive tissues.”

https://www.ncbi.nlm.nih.gov/pubmed/28743542

http://linkinghub.elsevier.com/retrieve/pii/S0960076017301887

Longitudinal study of hippocampal volumes in heavy cannabis users.

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SAGE Journals

“Cannabis exposure, particularly heavy cannabis use, has been associated with neuroanatomical alterations in regions rich with cannabinoid receptors such as the hippocampus in some but not in other (mainly cross-sectional) studies. However, it remains unclear whether continued heavy cannabis use alters hippocampal volume, and whether an earlier age of onset and/or a higher dosage exacerbate these changes.

Compared to controls, cannabis users did not show hippocampal volume alterations at either baseline or follow-up. Hippocampal volumes increased over time in both cannabis users and controls, following similar trajectories of increase. Cannabis dose and age of onset of cannabis use did not affect hippocampal volumes.

Continued heavy cannabis use did not affect hippocampal neuroanatomical changes in early adulthood. This contrasts with prior evidence on alterations in this region in samples of older adult cannabis users. In young adults using cannabis at this level, cannabis use may not be heavy enough to affect hippocampal neuroanatomy.”

 https://www.ncbi.nlm.nih.gov/pubmed/28741422
http://journals.sagepub.com/doi/10.1177/0269881117718380

Endocannabinoids in arthritis: current views and perspective.

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International Journal of Rheumatic Diseases

“Preclinical and clinical studies using cannabis-based therapy have been shown to provide both analgesia and anti-inflammatory effects, with an overall alleviation of clinical symptoms in animal models of arthritis, highlighting its promising therapeutic application for humans. Despite this, the development of cannabis-based therapeutics remains in its infancy, with further investigation into its efficacy and safety profile in patients still required. This synopsis reviews the various components of the endocannabinoid system in health and disease and their potential as therapeutic targets.”

https://www.ncbi.nlm.nih.gov/pubmed/28736968

http://onlinelibrary.wiley.com/doi/10.1111/1756-185X.13146/abstract

Neuroprotection by (endo)cannabinoids in glaucoma and retinal neurodegenerative diseases.

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“Emerging neuroprotective strategies are being explored to preserve the retina from degeneration, that occurs in eye pathologies like glaucoma, diabetic retinopathy, age-related macular degeneration, and retinitis pigmentosa. Incidentally, neuroprotection of retina is a defending mechanism designed to prevent or delay neuronal cell death, and to maintain neural function following an initial insult, thus avoiding loss of vision.

Numerous studies have investigated potential neuroprotective properties of plant-derived phytocannabinoids, as well as of their endogenous counterparts collectively termed endocannabinoids (eCBs), in several degenerative diseases of the retina.

eCBs are a group of neuromodulators that, mainly by activating G protein-coupled type-1 and type-2 cannabinoid (CB1 and CB2) receptors, trigger multiple signal transduction cascades that modulate central and peripheral cell functions. A fine balance between biosynthetic and degrading enzymes that control the right concentration of eCBs has been shown to provide neuroprotection in traumatic, ischemic, inflammatory and neurotoxic damage of the brain.

Since the existence of eCBs and their binding receptors was documented in the retina of numerous species (from fishes to primates), their involvement in the visual processing has been demonstrated, more recently with a focus on retinal neurodegeneration and neuroprotection. The aim of this review is to present a modern view of the endocannabinoid system, in order to discuss in a better perspective available data from preclinical studies on the use of eCBs as new neuroprotective agents, potentially useful to prevent glaucoma and retinal neurodegenerative diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/28738764

http://www.eurekaselect.com/154386/article