Stem cell/gene therapy holds HIV at bay in mouse trials
Scientists have successfully transplanted anti-HIV stem cells into mice that served as surrogates for infected patients. Bigger still, however, the process successfully expanded and safeguarded HIV-resistant immune cells, and the cells themselves kept growing even when confronted with the virus.
University of California-Davis Health System scientists came up with the process and say they're ready to test it in human clinical trials. To that end, they're applying for a grant to fuel human studies and seeking regulatory approval to proceed. If successful, they say, the system will essentially cure patients infected with HIV, by helping boost their immune system's ability to resist the virus.
"Ideally, it would be a one-time treatment through which stem cells express HIV-resistant genes, which in turn generate an entire HIV-resistant immune system," said Joseph Anderson, a professor and stem cell researcher at UC Davis' Institute for Regenerative Cures. He's also the lead author of a study detailing the finding, which is published in the May issue of the Journal of Virology.
"Ideally" is the key word here. The results in mice are promising enough but the real question will be if the phenomenon can be replicated in humans, which doesn't always happen. There have been plenty of promising discoveries generated by testing on mice that end up screeching to a halt once they didn't repeat in clinical trials involving people. And other researchers are testing similar uses of stem cells to attack and kill HIV. Still, this deserves further watching. A stem cell approach to treating HIV could be far more effective and lasting than the current regimen of antiretroviral drugs that help keep the disease at bay but don't cure it.
The scientists took several steps to reach their milestone, starting first with mice with immune systems that are similar to patients who have HIV. Next, they genetically modified human blood stem cells (food for producing all kinds of immune cells). Then, in a nod to previous work, they came up with several anti-HIV genes and, using standard gene therapy approaches along with viruses to carry the genes, they placed them into the blood cells. Finally, they introduced the cells into the mice and then confronted them with the virus.
What they found: The cells containing HIV-resistant genes were kept safe from infection and survived when confronted with the virus, keeping normal levels of CD4+ T-cells, which are immune cells targeted by HIV and then used to grow the virus. Even more significantly, the resistant cells grew after the HIV challenge, helping further to protect CD4.