Medical Research: What are the main findings of the study?
Dr. Cao: The major goal of this study was to investigate the effect of Ä9-tetrahydrocannabinol (THC), a major component of marijuana, on Alzheimer’s disease (AD) pathology. THC has long been known to have anti-inflammatory effects, but we were looking to determine whether THC directly affected amyloid beta (Aâ). Aâ aggregation is considered one of the key pathological hallmarks of Alzheimer’s disease. Our study showed that extremely low doses of THC were able to decrease Aâ production, inhibit Aâ aggregation, and enhance mitochondrial function in a cellular model of AD. Decreased levels of amyloid beta, coupled with THC’s inhibitory effect on aggregation may protect against the progression of Alzheimer’s disease.
Medical Research: Were any of the findings unexpected?
Dr. Cao: We were surprised at how little THC was needed to effectively decrease Aâ aggregation. The concentrations we used were at the nanomolar (10-9) level. We’re talking about very low concentrations of this stuff, likely low enough to avoid any potential adverse effects. Moreover, anti-Alzheimer’s effects seem to be mediated by multiple pathways, increasing the likelihood that it may be a useful compound in disease treatment.
Medical Research: What should clinicians and patients take away from your report?
Dr. Cao: Low levels of THC, when given at the correct time in the correct manner, may effectively treat Alzheimer’s disease. Recent reports, apart from our own, have shown that Aâ may inhibit the body’s endogenous cannabinoid system. Moreover, THC and THC related compounds reduce multiple pathological processes in AD mice. When this information is taken in concert with our study, THC should be considered a useful lead compound in the development of Alzheimer’s therapeutics.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Cao: The dose and target population are critically important for any drug, so additional research needs to be carried out to determine the most efficacious dosing regimens in the treatment of Alzheimer’s disease. THC has already been shown to be safe, and is used in the treatment of many other conditions in states that have legalized its medical use. Furthermore, there are currently no FDA approved disease modifying therapies for Alzheimer’s disease, only symptomatic treatments are available. Given the good safety profile and efficacy of extremely low doses in pre-clinical studies, clinicians should consider clinical trials in patients that have failed other available drugs.