A new study suggests that marijuana may have potential for protecting brain cells against Alzheimer’s disease.
Published in the June 2016 issue of Nature, the study found that tetrahydrocannabinol (THC), the main psychoactive compound in marijuana, and other active cannabis compounds could block the progression of the disease.
Lab tests by the Salk Institute, a Southern California nonprofit research organization, showed that marijuana compounds could remove harmful amyloid beta proteins, the plaque that accumulates on brain cells, which is a hallmark of Alzheimer’s disease. The compounds in the study also significantly reduced cellular inflammation, a major contributor to the onset of the disease.
David Schubert, senior author of the study and head of the cellular neurobiology laboratory at the Salk Institute, says the preliminary findings in this study could have potentially groundbreaking results. Schubert emphasizes that clinical trials on humans are needed, but if his THC compound drug testing is correct, it could be life-altering for those with Alzheimer’s.
“You’d have a product out there which is somewhat available and not too expensive, and which could really help millions of people,” Schubert says.
Alzheimer’s is an incurable brain disease that causes memory and mental deterioration with age. It affects more than 5 million Americans. According to a recent report by the Alzheimer’s Association, there are approximately 177,00 people living with Alzheimer’s in Los Angeles County. It’s one of the leading causes of death in the United States.
Schubert has been researching Alzheimer’s at the Salk Institute for almost 45 years. He says his lab works with natural products, such as curcumin — which is found in turmeric — and now cannabis, to make pharmaceuticals aimed at treating the disease.
“We’ve been interested in things that appear in nature for quite a long time. What we do is we find these compounds and we modify them chemically so they are more druglike and get into the brain better,” Schubert says.
In separate but related research, Schubert’s lab developed an Alzheimer’s drug called J147 that also removes amyloid beta from nerve cells and reduces the inflammatory response in the brain and nerve cells. One of the key ingredients to J147 is curcumin, a substance found in the plant turmeric, which Schubert studied after discovering Alzheimer’s rates in India were very low, where the spice is widely consumed as part of curry dishes. Schubert’s plant research to develop J147 led to the THC study. “It turns out that this J147 drug works through some of the same pathways, the same receptors, as the active component in marijuana — this THC compound,” says Schubert. He explains that the researchers put the THC on the cells and discovered it clears out the plaque, the same as J147, which means the marijuana component has a biological relevance to Alzheimer’s disease.
Current treatments don’t slow down or halt the disease in the brain, but if the Salk Institute’s preliminary study with the THC compound is correct, Schubert says patients would be able to get treatment before the disease progressed.
Keith Fargo, Ph.D., director of scientific programs at the Alzheimer’s Association, finds Schubert’s study promising. The association has even helped fund some of Schubert’s previous research with curcumin. “This is an interesting paper because it involves THC, which is active in marijuana, but there’s a lot more in this paper as well,” Fargo says. He adds that further research could even advance studies past marijuana itself. “It wouldn’t necessarily be the whole plant cannabis or even THC that would end up being used clinically. But it might be some other molecule that works through cannabinoid receptors to give you the effects you want, but that research has yet to be done.”
Cannabinoid receptors are part of a system of molecules that naturally occur throughout the body; known as endogenous cannabinoids, or endocannabinoids, they are remarkably similar to the active ingredient in marijuana. Researchers have found that the cannabinoid receptors are distributed widely throughout both the body and the brain, which suggests they play important roles in regulating our system — including our memory.
“There are many chemicals naturally occurring in the body that work through these cannabinoid receptors, and, of course, there are external factors as well, including THC and other compounds within marijuana and other plants,” Fargo says. Exercise, for example, has also been found to activate cannabinoid receptors.
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“We have no idea until a clinical trial is completed whether THC or any cannabinoid would be either safe or effective for human use. So we do not recommend the use of marijuana or cannabis in people who have Alzheimer’s,” Fargo says. He adds that there are unwanted side effects of cannabis consumption to consider: “Marijuana can cause memory problems in the short term, which would not be ideal for Alzheimer’s patients."
Meanwhile, Schubert’s inbox has been flooded with personal stories of the plant helping Alzheimer’s patients. “I got 50 different emails from people saying, ‘I’ve given my grandmother, mother, father or whatever marijuana, and it’s helped with Alzheimer’s.’ So I think there’s really something to this,” Schubert says. “If we can move these studies past the very basic tissue/culture pathway type analysis to animal studies, and really sort out what compounds and what the marijuana is doing, a lot of labs would be really interested in doing this. But right now with the legal structure and the social structure, this is very difficult to do.”
Schubert’s lab continues to face difficulties in furthering its studies on its THC compound because of the Catch-22 of how potential drugs are tested. Marijuana is classified as a Schedule 1 drug, in the same category as heroin and cocaine, which makes it extremely difficult for researchers to receive federal approval, as well as funding, to study the plant’s benefits. There’s also the social stigma of marijuana. Schubert says it is often viewed as addictive, but he says salt and sugar are likely more addictive than marijuana. Another hurdle for researchers, according to Schubert, is that more education is needed among the public and the medical community about the powerful plant.
“It’s really important to emphasize that there’s probably some really serious medicinal relevance to marijuana,” Schubert says. “It could be a good therapeutic itself. But unless you free up some legal aspects of studying this stuff, it’s very, very difficult to get either funding or approval.”