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Medical Marijuana Potpourri: Week 1
Yesterday, we focused on the historical facts regarding the medicinal use of cannabis. Today, we will focus on the use of marijuana in the treatment of methicillin-resistant Staphylococcus aureus and in the treatment of prion diseases.
Editors' Note: Medical marijuana has become an important area of study in healthcare. Doctors and healthcare professionals must understand the medical, legal, social and political issues to best respond to their patients’ questions and attend to their needs. This content area is not intended to encourage or dissuade the use of medical marijuana, but has been created to provide a balanced portrayal of the research in this area. The Drug Enforcement Agency issued “The DEA Position on Marijuana” in January 2011, which is their most recent position statement and provides information about medical marijuana and issues related to the conflicts between federal and state law.
Yes there is evidence, in pre-clinical studies. Scientists from Italy and the United Kingdom reported in the August 2007 issue of the Journal of Natural Products ([i]) that five major cannabinoids that were directly extracted from the cannabis plant—cannabidiol, cannabichromene, cannabigerol, Δ 9-tetrahydrocannabinol, and cannabinol—showed potent antibacterial activity against six different strains of MRSA of clinical relevance, with MIC (minimum inhibitory concentration) values in the 0.5-2 μg/mL range. In the assays, cannabinoids were as effective as vancomycin, and their mechanism of antibacterial activity is as-yet unknown and represents a new antibiotic class. This new class of antibiotics could be of aid, given the growing problem of antibiotic resistance.
[i] Appendino et al. Antibacterial Cannabinoids from Cannabis sativa: A Structure-Activity Study. Journal of NaturalProducts 2008, 71:8:1427-1430.
Yes there is evidence, in pre-clinical studies. Prion diseases are neurodegenerative diseases that are invariably fatal. They are characterized by the deposition of a pathological form of the prion protein resulting in a ‘spongiform’ appearance on post-mortem histological examination of neural tissue. In 2007, American and French researchers reported significant findings in an article entitled “Nonpsychoactive cannabidiol prevents prion accumulation and protects neurons against prion toxicity” in the Journal of Neuroscience ([i]). They reported that cannabidiol (CBD):
Inhibited prion accumulation in mouse and sheep prion disease cell cultures
Inhibited prion formation in the brain but not the spleen of infected mice given intraperitoneal injections of CBD (20 mg/kg, three times per week, for 3 weeks)
At the dose of 60 mg/kg increased survival time of infected mice by 5.7 days.
The authors conclude that CBD likely represents a new class of anti-prion drugs.
Brain endocannabinoid system research published in 2011 in Neuroscience ([ii]) showed that, in a mouse model of prion infection, there was upregulation of the endocannabinoid 2-arachidonoyglycerol (2-AG) 10 weeks post-infection and upregulation of CB2 receptor expression as early as 10-32 weeks post-infection. This data suggests that there are important alterations of the endocannabinoid system during early stages of prion diseases.
These findings are encouraging, as prions are very difficult to kill. According to the National Institute of Neurological Disorders and Stroke, presently there is no FDA-approved treatment that can cure or even control CJD. Researchers have tested many different types drugs to treat CJD. These drugs include amantadine, steroids, interferon, acyclovir, antiviral agents, and antibiotics. None of these drugs have successfully cured CJD.
[i] Dirikoc et al. Cannabidiol Prevents Prion Accumulation and Protects Neurons against Prion Toxicity. The Journal of Neuroscience 2007; 27(36):9537-9544.
[ii] Petrosino et al. Alteration of the endocannabinoid system in mouse brain during prion disease. Neuroscience 2011; 177:292-297.