Can
Cannabis Reduce HIV Disease Progression?
SUMMARY
THC, the main psychoactive component in marijuana, was
associated with decreased viral load and lower risk of
death in monkeys infected with a virus related to HIV. |
By
Liz Highleyman
Cannabis
has been shown in studies to improve appetite, relieve chronic
pain, and reduce nausea due to chemotherapy. Many people with
HIV/AIDS use medical marijuana
to combat wasting and other symptoms, which raises questions
about what effects it might have on HIV and its progression.
Many
immune cells express cannabinoid receptors, indicating that
cannabis may influence immune function. Some prior research
suggested that marijuana use is associated with HIV disease
progression, but such studies were prone to confounding by
socioeconomic and other factors related to illegal drug use.
As
described in the June
2011, issue of AIDS Research and Human Retroviruses,
Patricia Molina and colleagues from Louisiana State University
Health Sciences Center examined the impact of ongoing administration
of delta-9-tetrahydrocannabinol (THC) in macaque monkeys exposed
to simian immunodeficiency virus (SIV).
Eight rhesus macaques received twice-daily intramuscular injections
of either THC or a placebo. After 28 days, they were intravenously
inoculated with a highly infectious dose of SIV. The researchers
looked and immune and metabolic indicators of disease progression
during the initial 6-month asymptomatic phase after infection.
Results
 |
THC
administration did not significantly increase viral load
or exacerbate immune dysfunction. |
|
After
exposure to SIV, the monkeys showed measurable viral loads,
decreased CD4/CD8 T-cell ratios, and increased CD8 cell
proliferation. |
|
Administration
of cannabis prior to infection produced little or no effects
on these parameters. |
|
THC-treated monkeys lost CD4 cells more slowly than the
placebo group. |
|
Monkeys
given THC had a significantly lower early mortality rate
compared with placebo-treated animals. |
|
THC-treated
monkeys had lower plasma and cerebrospinal fluid SIV viral
load than those in the placebo group. |
|
Monkeys
in the THC group also experienced less wasting, though
the difference did not reach statistical significance.
|
|
In
a laboratory study, THC decreased SIV replication in MT4-R5?cells
in vitro. |
"These
results indicate that chronic [THC] does not increase viral
load or aggravate morbidity and may actually ameliorate SIV
disease progression," the study authors concluded.
"Two of the [placebo-treated] animals succumbed to SIV
infection shortly after 5 months, and a third reached end
stage at 7 months," they elaborated in their discussion.
"Among the [THC-treated] animals, the first animal did
not reach end stage until 11 months post-SIV inoculation.
"
"We speculate that reduced levels of SIV, retention of
body mass, and attenuation of inflammation are likely mechanisms
for [THC]-mediated modulation of disease progression that
warrant further study," they wrote.
Investigator affiliations: Departments of Physiology, Pharmacology,
Medicine, Microbiology, and Pathology, Louisiana State University
Health Sciences Center, New Orleans, LA; and School of Public
Health, Alcohol Research Center, and Alcohol and Drug Abuse
Center of Excellence, Louisiana State University Health Sciences
Center, New Orleans, LA.
5/31/11
Reference
PE
Molina, P Winsauer, P Zhang, et al. Cannabinoid Administration
Attenuates the Progression of Simian Immunodeficiency Virus.
AIDS Research and Human Retroviruses 27(6): 585-592 (free
full text). June 2011.
