People with HIVand other chronic conditions have used prescription marijuana to treat the side effects of medication for decades, but a new study published in the February issue of the journal AIDS Research and Human Retroviruses suggests that daily doses of one component found in marijuana could help cells fend off the virus.
The study is the second of its kind to indicate that delta-9-THC, the primary psychoactive ingredient found in marijuana, could help increase the number of healthy cells in HIV-positive patients who use the drug on a regular basis. A 2011 study by the same team of researchers at Louisiana State University Health Science Center’s Department of Physiology found that HIV-positive monkeys treated with daily doses of delta-9-THC had lower levels of viral infection, higher numbers of immune cells, better survival rates, and less weight loss.
In the most recent study, lead author Patricia Molina, MD, and her colleagues noted that delta-9-THC, given to male rhesus macaque monkeys before they were infected with simian immunodeficiency virus—the most common primate virus used to study HIV—decreased the subject’s likelihood of death and decreased the amount of the virus in the blood and lymph nodes. Similar results were shown when individual cells were exposed to delta-9-THC before being exposed to SIV. Chronic exposure to delta-9-THC also produced stronger anti-inflammatory immune signals and decreased apoptosis, or intestinal cell death.
“These findings may reveal novel mechanisms” for use of cannabinoids, that is, substances found in marijuana, to treat HIV infection, Molina says.
Molina notes that daily dosage of delta-9-THC, which was administered directly into the monkey’s muscle, also produced a tolerance to the drug, meaning higher doses were required over time to maintain the same effect. Molina’s team also noticed that even in its controlled form, delta-9-THC affected the monkeys’ ability to perform complex and memory-related tasks, and reduced receptors in the brain that responded to delta-9-THC.
However, Molina says the treatment did not produce a noticeable increase in food consumption, or, as she explains it, the monkeys had “no munchies.”
The doses of delta-9-THC used in Molina’s study are similar to those in prescription-strength dronabinol (Marinol), which uses a synthetic version of delta-9-THC and is approved by the Food and Drug Administration to treat HIV-associated anorexia and other conditions.
“Although this approval has gained strong support from the lay public, little scientific evidence exists to support the efficacy of such an intervention,” explains Molina. “Because of its ability to affect multiple organ systems, understanding its impact on metabolic, immune, and neurobehavioral function in HIV infection is essential and of paramount concern to public health officials.”
So do these results mean that HIV-positive marijuana users have actually been helping their body fight the disease all along? That’s not an accurate conclusion, says Molina, because there hasn’t been enough human research done to determine how the multiple effects of marijuana interact with existing antiretroviral therapies and compromised immune systems.
“With the advent of highly active antiretroviral therapy (HAART), HIV infection has become a chronic disease frequently coexisting with chronic use of drugs, including marijuana,” Molina says.
But Molina cautions against jumping to conclusions about the possible impact of marijuana use on HIV-positive humans. She says her results could have implications for humans, but emphasizes that the study only examined one chemical component of marijuana, which includes at least 60 other similar compounds.
“Marijuana is not synonymous with delta-9-THC, and the role of other cannabinoids in marijuana remains to be studied,” she says. Before human trials could be carried out, Molina says researchers would need to determine if other cannabinoid compounds found in marijuana could have similar effects on the immune system without the psychoactive effects induced by delta-9-THC.
Molina acknowledges, however, that the results of her study were somewhat surprising to the research team, especially since the study was funded by the National Institutes of Health and the National Institute on Drug Abuse.
“Based on previous studies, there was sufficient evidence to predict that chronic THC [exposure] would have a negative influence in overall markers of disease progression,” says Molina. “The fact that it did not was surprising.”
Instead, researchers found that chronic exposure to THC did not speed up the progression of the disease, did not worsen markers of the disease, and did not increase the rate at which the virus replicated. Such chronic exposure to the specific THC compound in the study could actually reduce viral load and the inflammation of gut tissue in male macaques, Molina says.
So while HIV-positive humans who use marijuana don’t yet have concrete scientific proof that the herb is good for them—and anything smoked and inhaled includes dangerous carcinogens—it’s safe to add Molina’s study to the growing body of evidence that the active ingredient in marijuana does have some legitimate medical properties.
Want to know what other marijuana studies have found? Read our rundown here.