Author Archives: David Worrell

The Cannabinoid Receptor Agonist THC Attenuates Weight Loss in a Rodent Model of Activity-Based Anorexia

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“Anorexia nervosa (AN) is characterized by anhedonia whereby patients experience little pleasure or reward in many aspects of their lives. Reward pathways and the endocannabionid system have been implicated in the mediation of food intake. The potential to exploit these systems to reverse weight loss is investigated in a rodent model of activity-based anorexia (ABA).

Given the powerful role of the endocannabionid system in stimulating reward processes and the apparent poor development of these processes in AN, it is important to test the hypothesis that exogenous administration of cannabinoid type 1 (CB1) receptor agonists can reverse the anorexia displayed in a rodent ABA model…

Importantly, the data presented here show for the first time the efficacy of THC  in retarding the progression of ABA…

In conclusion, these data establish for the first time the effectiveness of THC in rescuing animals from profound body weight loss associated with the development of ABA, independent of physical activity, which is enhanced if allowed access to highly palatable foods.

These results from the animal-based model of AN highlight the potential of cannabinoids and of the endocannabinoid system in the treatment of human anorexia.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3096804/

Cannabis and Δ9-tetrahydrocannabinol (THC) for weight loss?

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“Obesity is one of the highest preventable causes of morbidity and mortality in the developed world. It has been well known for a long time that exposure to cannabis produces an increase of appetite (a phenomenon referred to as the ‘munchies’). This phenomenon led to an exploration of the role of the endocannabinoid system in the regulation of obesity and associated metabolic syndrome.

This effort subsequently led to the development of a successful therapeutic approach for obesity that consisted of blocking the cannabinoid CB1 receptors using ligands such as Rimonabant in order to produce weight loss and improve metabolic profile. Despite being efficacious, Rimonabant was associated with increased rates of depression and anxiety and therefore removed from the market.

We recently discovered that the prevalence of obesity is paradoxically much lower in cannabis users as compared to non-users and that this difference is not accounted for by tobacco smoking status and is still present after adjusting for variables such as sex and age.

Here, we propose that this effect is directly related to exposure to the Δ(9)-tetrahydrocannabinol (THC) present in cannabis smoke.

We therefore propose the seemingly paradoxical hypothesis that THC or a THC/cannabidiol combination drug may produce weight loss and may be a useful therapeutic for the treatment of obesity and its complications.”

http://www.ncbi.nlm.nih.gov/pubmed/23410498

Amphiregulin is a factor for resistance of glioma cells to cannabinoid-induced apoptosis.

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“Gliomas, one of the most malignant forms of cancer, exhibit high resistance to conventional therapies. Identification of the molecular mechanisms responsible for this resistance is therefore of great interest to improve the efficacy of the treatments against these tumors. Delta9-Tetrahydrocannabinol (THC), the major active ingredient of marijuana, and other cannabinoids inhibit tumor growth in animal models of cancer, including glioma, an effect that relies, at least in part, on the ability of these compounds to induce apoptosis of tumor cells.

…we identified the epidermal growth factor receptor ligand amphiregulin as a candidate factor to mediate the resistance of glioma cells to cannabinoid treatment… in vivo silencing of amphiregulin rendered the resistant tumors xenografts sensitive to cannabinoid antitumoral action.

Amphiregulin expression was associated with increased extracellular signal-regulated kinase (ERK) activation, which mediated the resistance to THC by blunting the expression of p8 and TRB3-two genes involved in cannabinoid-induced apoptosis of glioma cells.

 Our findings therefore identify Amphirregulin as a factor for resistance of glioma cells to THC-induced apoptosis and contribute to unraveling the molecular bases underlying the emerging notion that targeted inhibition of the EGFR pathway can improve the efficacy of antitumoral therapies.”

http://www.ncbi.nlm.nih.gov/pubmed/19229996

Stimulation of the midkine/ALK axis renders glioma cells resistant to cannabinoid antitumoral action

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“Δ9-Tetrahydrocannabinol (THC), the major active ingredient of marijuana, and other cannabinoids inhibit tumor growth in animal models of cancer, including glioma, an effect that relies, at least in part, on the stimulation of autophagy-mediated apoptosis in tumor cells. 

…Altogether, our findings identify Mdk as a pivotal factor involved in the resistance of glioma cells to THC pro-autophagic and antitumoral action, and suggest that selective targeting of the Mdk/ALK axis could help to improve the efficacy of antitumoral therapies for gliomas.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3131933/

Stimulation of ALK by the growth factor midkine renders glioma cells resistant to autophagy-mediated cell death

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“Δ9-tetrahydrocannabinol (THC), the main active component of marijuana, promotes cancer cell death via autophagy stimulation.

We find that activation of the tyrosine kinase receptor ALK by its ligand midkine interferes with the signaling mechanism by which THC promotes autophagy-mediated glioma cell death.”

 http://www.ncbi.nlm.nih.gov/pubmed/21593591

Marijuana Chemical May Fight Brain Cancer – CBSNews

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“The active chemical in marijuana promotes the death of brain cancer cells by essentially helping them feed upon themselves, researchers in Spain report.

Guillermo Velasco and colleagues at Complutense University in Spain have found that the active ingredient in marijuana, THC, causes brain cancer cells to undergo a process called autophagy. Autophagy is the breakdown of a cell that occurs when the cell essentially self-digests.

The team discovered that cannabinoids such as THC had anticancer effects in mice with human brain cancer cells and people with brain tumors . When mice with the human brain cancer cells received the THC, the tumor growth shrank.

Two patients enrolled in a clinical trial received THC directly to the brain as an experimental treatment for recurrent glioblastoma multiforme , a highly aggressive brain tumor. Biopsies taken before and after treatment helped track their progress. After receiving the THC, there was evidence of increased autophagy activity.

The findings appear in the April 1 issue of the Journal of Clinical Investigation.

The patients did not have any toxic effects from the treatment. Previous studies of THC for the treatment of cancer have also found the therapy to be well tolerated, according to background information in journal article.

Study authors say their findings could lead to new strategies for preventing tumor growth.”

http://www.cbsnews.com/2100-500368_162-4913095.html

“Cannabinoid action induces autophagy-mediated cell death through stimulation of ER stress in human glioma cells…These findings describe a mechanism by which THC can promote the autophagic death of human and mouse cancer cells and provide evidence that cannabinoid administration may be an effective therapeutic strategy for targeting human cancers.” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2673842/

 

Cannabinoid receptor 1 deficiency in a mouse model of Alzheimer’s disease leads to enhanced cognitive impairment despite of a reduction in amyloid deposition.

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“Alzheimer’s disease (AD) is characterized by amyloid-β deposition in amyloid plaques, neurofibrillary tangles, inflammation, neuronal loss, and cognitive deficits. Cannabinoids display neuromodulatory and neuroprotective effects and affect memory acquisition. Here, we studied the impact of cannabinoid receptor type 1 (CB1) deficiency on the development of AD pathology…

…the findings indicate that CB1 deficiency can worsen AD-related cognitive deficits and support a potential role of CB1 as a pharmacologic target.”

http://www.ncbi.nlm.nih.gov/pubmed/23838176

Structure-dependent inhibitory effects of synthetic cannabinoids against 12-O-tetradecanoylphorbol-13-acetate-induced inflammation and skin tumour promotion in mice.

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“Whether and how synthetic cannabinoids affect inflammation and carcinogenesis has not been well studied. The present study was thus conducted to assess effects of synthetic cannabinoids on inflammation and carcinogenesis in vivo in mice…

The present results suggest that synthetic cannabinoids, such as JWH-018, -122 and -210, may be used as cancer chemopreventive agents in the future.”

http://www.ncbi.nlm.nih.gov/pubmed/23837590

Biochemical and immunohistochemical changes in delta-9-tetrahydrocannabinol-treated type 2 diabetic rats.

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“The regulation of glucose, lipid metabolism and immunoreactivities of insulin and glucagon peptides by delta-9-tetrahydrocannabinol (Δ9-THC) in diabetes were examined in an experimental rat model… 

These results indicate that Δ9-THC may serve a protective role against hyperlipidemia and hyperglycemia in diabetic rats.”

http://www.ncbi.nlm.nih.gov/pubmed/23845579

CB1 Cannabinoid Receptor Agonist Prevents NGF-Induced Sensitization of TRPV1 in Sensory Neurons.

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“The transient receptor potential vanilloid type 1 channel (TRPV1) and nerve growth factor (NGF) are important mediators of inflammatory pain…

Cannabinoids, by activating CB1 G protein-coupled receptors, produce analgesia in a variety of pain models, though the exact mechanisms are not known. We tested the hypothesis that activation of the CB1 receptor by cannabinoids attenuates NGF-induced TRPV1 sensitization….

These results support the hypothesis that cannabinoids, acting through CB1 receptors, may produce analgesia in part by preventing NGF-induced sensitization of TRPV1 in afferent nociceptor nerve endings.”

http://www.ncbi.nlm.nih.gov/pubmed/23850608