COCAINE SPEEDS HIV'S SPREAD IN CELLS
By E. J. Mundell
Reuters 14 Feb. 2002
New York -- Experts have long known that cocaine abuse
encourages risky behaviors linked to infection with HIV. Now, research
in mice suggests the drug may also speed the cell-to-cell spread of
the virus by up to 200-times.
"This is important, because cocaine use--specifically crack
cocaine--is a significant public health problem, and it's particularly
significant in populations at risk for contracting HIV," said
researcher Dr. Gayle Baldwin, of the University of California, Los
Angeles. Her team published their findings in the March issue of the
Journal of Infectious Diseases.
Previous population-based studies have suggested that HIV-related
disease progresses faster in drug abusers than in non-users. However,
ethical and practical concerns have meant that its nearly impossible
to carry out studies that would measure the effects of cocaine on HIV
spread at the cellular level.
In their research, Baldwin's team developed a mouse model of human HIV
infection. They first transplanted human cells into mice, then
infected those cells with HIV. Next, they fed some of the mice cocaine
in liquid form, at dosages roughly comparable to those used by human
addicts. The rest of the mice received no cocaine.
"What we found was that cocaine use dramatically accelerated the
spread of HIV infection," Baldwin told Reuters Health. In fact, the
blood cells of mice fed cocaine had nearly 200 times the level of
virus of those who did not receive the drug.
Furthermore, cocaine-fed rodents experienced significant injury to
their immune systems, as well. "There was a dramatic decrease in the
number of CD4+ T cells--these are one of the primary cellular immune
defenders, and the target cell of choice for HIV," Baldwin said.
According to the researchers, the number of CD4+ cells fell 9 times
faster in rats fed cocaine versus those that were not.
The exact mechanisms behind cocaine's impact on HIV and immune health
remains unclear. "There certainly are some targets we can look at,"
Baldwin said. "Cocaine doesn't work by itself...it has a number of
byproducts, and these byproducts can act on HIV. These can include
things as straightforward as cellular mediators such as cytokines,
compounds which have been already shown to have an effect on HIV
replication." Cocaine and its byproducts might also help HIV break
Regardless of the way in which it wreaks havoc with HIV, the message
to HIV-positive individuals--or anyone else--seems clear: stay away
"Even if cocaine had no effect on HIV replication, the consequences of
use in immune-compromised population is very straightforward," Baldwin
noted. But evidence that cocaine could actually speed the spread of
HIV within cells may now mean that "the caution against this sort of
recreational drug use has now been increased 200-fold," she said.
Source: The Journal of Infectious Diseases, 2002:185:701-705.