Reversal of age-related cognitive impairments in mice by an extremely low dose of tetrahydrocannabinol.

Posted on November 7, 2017 by David Worrell

Neurobiology of Aging

“This study was designed to test our hypothesis that an ultra-low dose of delta-9 tetrahydrocannabinol (THC) reverses age-dependent cognitive impairments in old mice and to examine the possible biological mechanisms that underlie this behavioral effect. These findings suggest that extremely low doses of THC that are devoid of any psychotropic effect and do not induce desensitization may provide a safe and effective treatment for cognitive decline in aging humans.” https://www.ncbi.nlm.nih.gov/pubmed/29107185

“Cognitive decline is an integral aspect of aging. The idea that age-related cognitive decline can be reversed and that the old brain can be revitalized is not new. It has been previously suggested that the endocannabinoid system is part of an antiaging homeostatic defense system. In previous studies, we have shown that ultra-low doses of tetrahydrocannabinol (THC, the main psychotropic ingredient in cannabis) protected young mice from cognitive impairments that were evoked by various insults. In the present study, we tested our hypothesis that a single ultra-low dose of THC can reverse age-dependent cognitive decline in mice. Here, we show that a single extremely low dose of THC devoid of any psychotropic activity can trigger an endogenous compensatory mechanism that improves cognitive functioning in old mice and that this effect lasts for at least several weeks. Since THC in high doses (dronabinol, 1–10 mg) is already approved for medical treatments in humans, and since its safety profile is well characterized, we believe that the initiation of clinical trials with ultra-low doses of THC designed to reverse cognitive decline in elderly patients should be straightforward.” http://www.sciencedirect.com/science/article/pii/S0197458017303214

“Reversal of age-related cognitive impairments in mice by an extremely low dose of tetrahydrocannabinol. These findings suggest that extremely low doses of THC that are devoid of any psychotropic effect and do not induce desensitization may provide a safe and effective treatment for cognitive decline in aging humans.” http://www.neurobiologyofaging.org/article/S0197-4580(17)30321-4/fulltext

A Systematic Review of the Effectiveness of Medical Cannabis for Psychiatric, Movement and Neurodegenerative Disorders.

Posted on October 29, 2017 by David Worrell

“The discovery of endocannabinoid’s role within the central nervous system and its potential therapeutic benefits have brought forth rising interest in the use of cannabis for medical purposes. The present review aimed to synthesize and evaluate the available evidences on the efficacy of cannabis and its derivatives for psychiatric, neurodegenerative and movement disorders. A systematic search of randomized controlled trials of cannabis and its derivatives were conducted via databases (PubMed, Embase and the Cochrane Central Register of Controlled Trials). A total of 24 reports that evaluated the use of medical cannabis for Alzheimer’s disease, anorexia nervosa, anxiety, dementia, dystonia, Huntington’s disease, Parkinson’s disease, post-traumatic stress disorder (PTSD), psychosis and Tourette syndrome were included in this review. Trial quality was assessed with the Cochrane risk of bias tool. There is a lack of evidence on the therapeutic effects of cannabinoids for amyotrophic lateral sclerosis and dystonia. Although trials with positive findings were identified for anorexia nervosa, anxiety, PTSD, psychotic symptoms, agitation in Alzheimer’s disease and dementia, Huntington’s disease, and Tourette syndrome, and dyskinesia in Parkinson’s disease, definitive conclusion on its efficacy could not be drawn. Evaluation of these low-quality trials, as rated on the Cochrane risk of bias tools, was challenged by methodological issues such as inadequate description of allocation concealment, blinding and underpowered sample size. More adequately powered controlled trials that examine the long and short term efficacy, safety and tolerability of cannabis for medical use, and the mechanisms underpinning the therapeutic potential are warranted.”

https://www.ncbi.nlm.nih.gov/pubmed/29073741

http://www.cpn.or.kr/journal/view.html?doi=10.9758/cpn.2017.15.4.301

Effects of cannabidiol interactions with Wnt/β-catenin pathway and PPARγ on oxidative stress and neuroinflammation in Alzheimer’s disease.

Posted on October 6, 2017 by David Worrell

Issue Cover

“Alzheimer’s disease (AD) is a neurodegenerative disease, in which the primary etiology remains unknown. AD presents amyloid beta (Aβ) protein aggregation and neurofibrillary plaque deposits. AD shows oxidative stress and chronic inflammation.

In AD, canonical Wingless-Int (Wnt)/β-catenin pathway is downregulated, whereas peroxisome proliferator-activated receptor γ (PPARγ) is increased. Downregulation of Wnt/β-catenin, through activation of glycogen synthase kinase-3β (GSK-3β) by Aβ, and inactivation of phosphatidylinositol 3-kinase/Akt signaling involve oxidative stress in AD.

Cannabidiol (CBD) is a non-psychotomimetic phytocannabinoid from Cannabis sativa plant. In PC12 cells, Aβ-induced tau protein hyperphosphorylation is inhibited by CBD. This inhibition is associated with a downregulation of p-GSK-3β, an inhibitor of Wnt pathway. CBD may also increase Wnt/β-catenin by stimulation of PPARγ, inhibition of Aβ and ubiquitination of amyloid precursor protein.

CBD attenuates oxidative stress and diminishes mitochondrial dysfunction and reactive oxygen species generation. CBD suppresses, through activation of PPARγ, pro-inflammatory signaling and may be a potential new candidate for AD therapy.”

https://www.ncbi.nlm.nih.gov/pubmed/28981597

https://academic.oup.com/abbs/article-abstract/49/10/853/3978657/Effects-of-cannabidiol-interactions-with-Wnt?redirectedFrom=fulltext

Delta-9-Tetrahydrocannabinol (∆9-THC) Induce Neurogenesis and Improve Cognitive Performances of Male Sprague Dawley Rats.

Posted on September 22, 2017 by David Worrell

“Neurogenesis is influenced by various external factors such as enriched environments. Some researchers had postulated that neurogenesis has contributed to the hippocampal learning and memory. This project was designed to observe the effect of Delta-9-tetrahydrocannabinol (∆⁹-THC) in cognitive performance that influenced by the neurogenesis. Different doses of ∆⁹-THC were used for observing the neurogenesis mechanism occurs in the hippocampus of rats. The brains were stained with antibodies, namely BrdU, glial fibrillary acidic protein (GFAP), nestin, doublecortin (DCX) and class III β-tubulin (TuJ-1). The cognitive test was used novel-object discrimination test (NOD) while the proteins involved, DCX and brain-derived neurotrophic factor (BDNF), were measured. Throughout this study, ∆⁹-THC enhanced the markers involved in all stages of neurogenesis mechanism. Simultaneously, the cognitive behaviour of rat also showed improvement in learning and memory functions observed in behavioural test and molecular perspective. Administration of ∆⁹-THC was observed to enhance the neurogenesis in the brain, especially in hippocampus thus improved the cognitive function of rats.” https://www.ncbi.nlm.nih.gov/pubmed/28933048

https://link.springer.com/article/10.1007%2Fs12640-017-9806-x

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Receptor-heteromer mediated regulation of endocannabinoid signaling in activated microglia. Role of CB1 and CB2 receptors and relevance for Alzheimer's disease and levodopa-induced dyskinesia.

Posted on August 29, 2017 by David Worrell

“Endocannabinoids are important regulators of neurotransmission and, acting on activated microglia, they are postulated as neuroprotective agents. Endocannabinoid action is mediated by CB₁ and CB₂ receptors, which may form heteromeric complexes (CB₁-CB₂Hets) with unknown function in microglia. We aimed at establishing the expression and signaling properties of cannabinoidreceptors in resting and LPS/IFN-γ-activated microglia. Unlike CB₁, CB₂ receptors and CB₁-CB₂Hets were upregulated in activated microglia. Resting cell refractory CB₂ receptors became robustly coupled to G_i in activated cells, in which CB₁-CB₂Hets mediated a positive cross-talk. Resting cells were refractory while activated cells were highly responsive to cannabinoids. Interestingly, similar results were obtained in cultures treated with ß-amyloid (Aß_1-42). Activation microglial markers were detected in the striatum of a Parkinson’s disease (PD) model and, remarkably, in primary microglia cultures from the hippocampus of mutant β-amyloid precursor protein (APP_Sw,Ind) mice, a transgenic Alzheimer’s disease (AD) model. Also of note was the similar cannabinoid receptor signaling found in primary cultures of microglia from APP_Sw,Ind and in cells from control animals activated using LPS plus IFN- γ. Expression of CB₁-CB₂Hets was increased in the striatum from rats rendered dyskinetic by chronic levodopa treatment. In summary, our results showed sensitivity of activated microglial cells to cannabinoids, increased CB₁-CB₂Het expression in activated microglia and in microglia from the hippocampus of an AD model, and a correlation between levodopa-induced dyskinesia and striatal microglial activation in a PD model. Cannabinoid receptors and the CB₁-CB₂ heteroreceptor complex in activated microglia have potential as targets in the treatment of neurodegenerative diseases.” https://www.ncbi.nlm.nih.gov/pubmed/28843453 http://www.sciencedirect.com/science/article/pii/S0889159117304038]]>

Receptor-heteromer mediated regulation of endocannabinoid signaling in activated microglia. Role of CB1 and CB2 receptors and relevance for Alzheimer’s disease and levodopa-induced dyskinesia.

Posted on August 29, 2017 by David Worrell

Cover image

We aimed at establishing the expression and signaling properties of cannabinoidreceptors in resting and LPS/IFN-γ-activated microglia. Unlike CB₁, CB₂ receptors and CB₁-CB₂Hets were upregulated in activated microglia. Resting cell refractory CB₂ receptors became robustly coupled to G_i in activated cells, in which CB₁-CB₂Hets mediated a positive cross-talk. Resting cells were refractory while activated cells were highly responsive to cannabinoids. Interestingly, similar results were obtained in cultures treated with ß-amyloid (Aß_1-42). Activation microglial markers were detected in the striatum of a Parkinson’s disease (PD) model and, remarkably, in primary microglia cultures from the hippocampus of mutant β-amyloid precursor protein (APP_Sw,Ind) mice, a transgenic Alzheimer’s disease (AD) model. Also of note was the similar cannabinoid receptor signaling found in primary cultures of microglia from APP_Sw,Ind and in cells from control animals activated using LPS plus IFN- γ. Expression of CB₁-CB₂Hets was increased in the striatum from rats rendered dyskinetic by chronic levodopa treatment.

In summary, our results showed sensitivity of activated microglial cells to cannabinoids, increased CB₁-CB₂Het expression in activated microglia and in microglia from the hippocampus of an AD model, and a correlation between levodopa-induced dyskinesia and striatal microglial activation in a PD model. Cannabinoid receptors and the CB₁-CB₂ heteroreceptor complex in activated microglia have potential as targets in the treatment of neurodegenerative diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/28843453

http://www.sciencedirect.com/science/article/pii/S0889159117304038

Modulation of Astrocyte Activity by Cannabidiol, a Nonpsychoactive Cannabinoid.

Posted on August 10, 2017 by David Worrell

“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]]>

Modeling Neurodegenerative Disorders for Developing Cannabinoid-Based Neuroprotective Therapies.

Posted on August 2, 2017 by David Worrell

“The increase in lifespan during the last 50 years, mainly in developed countries, has originated a progressive elevation in the incidence of chronic neurodegenerative disorders, for which aging is the key risk factor. This fact will definitively become the major biomedical challenge during the present century, in part because the expectation of a persisting elevation in the population older than 65 years over the whole population and, on the other hand, because the current lack of efficacious therapies to control these disorders despite years of intense research. This chapter will address this question and will stress the urgency of developing better neuroprotective and neurorepair strategies that may delay/arrest the progression of these disorders, reviewing the major needs to solve the causes proposed for the permanent failures experienced in recent years, e.g., to develop multitarget strategies, to use more predictive experimental models, and to identify early disease biomarkers. This chapter will propose the cannabinoids and their classic (e.g., endocannabinoid receptors and enzymes) and nonclassic (e.g., peroxisome proliferator-activated receptors, transcription factors) targets as a useful strategy for developing novel therapies for these disorders, based on their broad-spectrum neuroprotective profile, their activity as an endogenous protective system, the location of the endocannabinoid targets in cell substrates critical for neuronal survival, and their ability to serve for preservation and rescue, but also for repair and/or replacement, of neurons and glial cells against cytotoxic insults.” https://www.ncbi.nlm.nih.gov/pubmed/28750802 http://www.sciencedirect.com/science/article/pii/S0076687917301787?via%3Dihub]]>

Alleviation of Neuropathology by Inhibition of Monoacylglycerol Lipase in APP Transgenic Mice Lacking CB2 Receptors.

Posted on July 24, 2017 by David Worrell

“Inhibition of monoacylglycerol lipase (MAGL), the primary enzyme that hydrolyzes the endocannabinoid 2-arachidonoylglycerol (2-AG) in the brain, produces profound anti-inflammatory and neuroprotective effects and improves synaptic and cognitive functions in animal models of Alzheimer’s disease (AD). However, the molecular mechanisms underlying the beneficial effects produced by inhibition of 2-AG metabolism are still not clear. The cannabinoid receptor type 2 (CB2R) has been thought to be a therapeutic target for AD. Here, we provide evidence, however, that CB2R does not play a role in ameliorating AD neuropathology produced by inactivation of MAGL in 5XFAD APP transgenic mice, an animal model of AD. Our results suggest that CB2R is not required in ameliorating neuropathology and preventing cognitive decline by inhibition of 2-AG metabolism in AD model animals.”

https://www.ncbi.nlm.nih.gov/pubmed/28733897

https://link.springer.com/article/10.1007%2Fs12035-017-0689-x

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Amyloid proteotoxicity initiates an inflammatory response blocked by cannabinoids.

Posted on July 20, 2017 by David Worrell

“The beta amyloid (Aβ) and other aggregating proteins in the brain increase with age and are frequently found within neurons. The mechanistic relationship between intracellular amyloid, aging and neurodegeneration is not, however, well understood. We use a proteotoxicity model based upon the inducible expression of Aβ in a human central nervous system nerve cell line to characterize a distinct form of nerve cell death caused by intracellular Aβ. It is shown that intracellular Aβ initiates a toxic inflammatory response leading to the cell’s demise. Aβ induces the expression of multiple proinflammatory genes and an increase in both arachidonic acid and eicosanoids, including prostaglandins that are neuroprotective and leukotrienes that potentiate death. Cannabinoids such as tetrahydrocannabinol stimulate the removal of intraneuronal Aβ, block the inflammatory response, and are protective. Altogether these data show that there is a complex and likely autocatalytic inflammatory response within nerve cells caused by the accumulation of intracellular Aβ, and that this early form of proteotoxicity can be blocked by the activation of cannabinoid receptors.”

https://www.ncbi.nlm.nih.gov/pubmed/28721267

https://www.nature.com/articles/npjamd201612

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Category Archives: Alzheimer’s Disease (AD)