Approximately 50,000 new HIV infections are reported in the United States every year, according to the HIV Surveillance Supplemental Report of 2012. It inevitably progresses into chronic AIDS, and as no major, straightforward cure exists, scientists have proposed alternative treatments as a means of mitigating the disease’s effects.
Now, researchers believe that tetrahydrocannabinol (THC) in medical marijuana can play an important role in treating patients with HIV by protecting immune tissues in the gut from the spread of the infection, according to an article published in AIDS Research and Human Retroviruses.
A team of researchers at the Louisiana State University Health Sciences Center tested the effects of THC, the main psychoactive ingredient in marijuana, on gut tissue of SIV-infected rhesus macaques, according to a Feb. 18 press release.
“SIV is what is used in this study to infect rhesus macaques, and this is a very strong animal model for mirroring HIV infections in humans,” said Rahm Gummuluru, a Boston University professor of microbiology.
Some macaques, which are a type of smaller monkeys found across a variety of habitats in Asia, were given THC while a control group was given placebos. Researchers gave chronic dosage levels of THC over a period of 17 months, said Patricia Molina, head author of the report.
At the end of the trial period, researchers observed lower circulation of the SIV virus: cells in the macaques treated with THC.
“Chronic THC, starting 30 days prior to simian immunodeficiency virus inoculation, decreased early mortality from SIV infection and lowered the amount of virus in circulation and in lymph nodes,” she said.
Additionally, the experimental group experienced less inflammation in the gut area. This lower level of inflammation prevents excessive immune system responses, such as the body’s creation of cytokines.
“When our bodies, or in this case monkeys, are infected with SIV, we generate a lot of immune responses,” Gummuluru said. “We make molecules like cytokines which help our bodies to fight pathogen-like viruses.”
However, the immune system’s excessive response of producing these virus fighting-molecules becomes detrimental over time, Gummuluru said.
“It turns out, when we get infected by viruses such SIV or HIV, we tend to make more than what is necessary,” he said. “It is an over-exuberant response to the pathogen. So our tissues are dying because we make more cytokines than necessary, more antiviral factors than necessary.”
Cytokines are essentially proteins that mediate between cells. In the guts of the THC-administered macaques, there was less activation to create these molecules. This slowed production of cytokines allowed for a longer survival of T-cells, which are white blood cells that fight invading pathogens.
“The reason why HIV is so deadly is because it infects the very cells that we need to fight the virus,” Gummuluru said. “So, it kills these T-cells very rapidly, and our body continuously makes the T-cells because that is part of our immune system to make cells as they die out.”
The positive effect of the THC on T-cell population, along with the lesser viral loads in this experimental group, support curiosity for the usage of psychoactive ingredients in the arena of long-term virus treatment.
“What this gets to is this argument over whether one can slow down the disease by giving immunosuppressive reagents to people or individuals,” Gummuluru said. “There’s not a cure. There’s just no way to help the immune system fight the virus, but you can prolong life.”
However, Molina said researchers must examine the role of other components of marijuana before advocating for its use as a treatment for HIV.
“The scarcity of scientific evidence concurs with the conclusions of the report from the White House’s Office of National Drug Control Policy on the need for understanding the long-term effects of cannabinoid use on the body, mental health and behavior, particularly on the potential beneficial or detrimental effects in the course of chronic diseases,” she said.
This investigation of the effects of THC among viral disease ties into the ongoing, nationwide discussion of medical marijuana usage. In November 2012, Massachusetts residents voted to allow medical marijuana in the Commonwealth.
BU students have involved themselves in the conversation on the role of medical marijuana, most notably through the group Students for Sensible Drug Policy. The club’s overall mission is to provide information regarding drug usage and policy in promotion of public health education throughout the community, said club president Melanie Kirsh.
“We don’t condone or condemn drug use, and we do believe that medical marijuana is the right way to go,” Kirsh, a College of Arts and Sciences sophomore, said.
The club supported this stance by campaigning for medical cannabis legalization during the voting period in Massachusetts.
“The reasoning why we wanted people to vote yes was because that people with chronic diseases or illnesses benefit so much from the usage of medical cannabis because it’s a pain reliever,” Kirsh said.
Despite the official legalization in the Commonwealth, the benefits of medical marijuana do not have everybody sold. The drug’s psychoactive effects, through the eyes of some scientists and citizens, are not tame enough for regulated usage.
“Its principal risks are of dependence, bad interactions with existing mental health and substance abuse problems, and problems with present and even future cognition, particularly among adolescents” said Dr. Timothy Naimi, a BU School of Medicine professor.
Although traditional pain relief differs from the slowing down of HIV and SIV progression, the usage of THC and other psychoactive cannabinoids as a medical treatment remains the central theme to the conversation. Despite potential flaws in medical marijuana, the research of this LSU team provides an example that the THC contained can prove to be a positive.
“Because gut associated lymphoid tissues have been shown to play important roles in the infection, these findings may reveal novel mechanisms that potentially contribute to cannabinoid-mediated disease modulation” Molina said. The doctor plans on conducting follow-up research on the topic.