Marijuana Improves Cognition in HIV Patients

Norbert Kaminski, PhD

Medical marijuana could help prevent the development of neurocognitive disorders in patients with HIV, according to a new study.

Tetrahydrocannabinol (THC), the prominent compound in marijuana, was found to slow the process of neurodegeneration — a condition common in about half of all patients with HIV — according to a study from researchers at Michigan State University (MSU).

Norbert Kaminski, PhD, author and director for the Institute for Integrative Toxicology, and Professor of Pharmacology and Toxicology, told MD Magazine the neurodegenerative process in patients HIV is driven in part of monocytes, the white blood cells that cause low-level chronic inflammation in the brain and the destruction of neurons.

Patients’ immune systems are almost constantly stimulated for fighting the virus, causing chronic inflammation in the brain.

In healthy individuals, about 5% to 15% of active monocytes are expressing inflammation markers, Kaminski said. In patients with HIV, about 40% to 60% of monocytes are expressing the markers. The result is a great variation of cognitive issues in patients with HIV.

“It can really run the gamut, from being relatively mild to, in extreme cases, what you observe in an Alzheimer’s patient,” Kaminski said.

In a comparative study involving patients with HIV who were either treated with medical marijuana or not, Kaminski and a colleague analyzed donor’s isolated white blood cells, to observe marijuana’s effect on inflammatory cell levels.

Researchers found that treated patients reported monocyte expression rates similar to that of healthy individuals again. The marijuana served as anti-inflammatory agent, reducing the number of monocytes in patients.

To Kaminski’s knowledge, only a handful of published studies have focused on marijuana’s effect on the immune system. The HIV patient population is difficult to analyze for new therapies due to the limited class of animal subjects that can be infected with a human-like form of the virus.

That said, the 40-patient study gives researchers a new possibility to follow in inflammation therapy.

“The anti-inflammatory properties were not novel,” Kaminski said. “What was novel was the rate of decrease of monocytes in these patients.”

A similar study into therapies for cognition in patients with HIV last month found that early antiretroviral therapy can have a similarly positive effect in treating neurolgical conditions.

Though medical marijuana is not an uncommon therapy in patients with HIV, it’s been often prescribed for stimulating patient appetite, relieving anxiety surrounding the condition, or to combat adverse effects from other therapies, Kaminski said.

For as much as it could be a breakthrough in HIV therapy, there’s even wider indication for the researchers’ discoveries.

“The implications go beyond these patients — that rate of neuroinflammation has also been indicated in neurological disorders such as Parkinson’s disease and Alzheimer’s disease,” Kaminski said.

Consideration for these indications, in studies with expanded patient populations, would be considered for follow-up research.

The study, "HIV-infected cannabis users have lower circulating CD16+ monocytes and IP-10 levels compared to non-using HIV patients," was published online in the journal AIDS last month.