The researchers say they are one step closer to finding a potential cure for HIV after successfully eliminating the virus in live mice for the first time.
Using a combination of CRISPR gene editing technology and a therapeutic treatment called LASER ART, scientists at Temple University and the University of Nebraska Medical Center stated that they had erased HIV DNA from animal genomes in what they call an unprecedented study published Tuesday in the journal Nature Communications.
"We think this study is an important step forward because for the first time it shows after 40 years of the AIDS epidemic that HIV disease is a curable disease," said study co-author Dr. Kamel Khalili, chairman of the department of neuroscience and director of the Center for Neurovirology and the complete NeuroAIDS Center at Temple University.
About 1.1 million people in the United States live with HIV, a virus that attacks the body's immune system and makes a person more susceptible to getting sick. If HIV is not treated, it can turn into AIDS, a disease in which the virus severely damages the immune system. People with AIDS live on average about 3 years after their diagnosis, according to HIV.gov.
The virus is currently treated with antiretroviral therapy (ART), which suppresses it from replication and prevents many patients in the United States from developing AIDS. ART does not eliminate the body of HIV, however, and if a patient stops treatment the virus will continue to replicate.
But now researchers say they are able to destroy the virus in "humanized" mice, which have been injected with human bone marrow to mimic the human immune system.
The study authors used two different tools to fight the virus: CRISPR and LASER ART technology.
CRISPR-Cas9 is a gene modification tool that has been boasted as a revolutionary technology that can help researchers cure or potentially cure genetic diseases. It gives scientists the ability to modify an organism's DNA so they can add, remove or modify certain genetic materials.
LASER ART is a "super" form of ART that maintains replication of the virus at low levels for longer periods of time, according to co-author Dr. Howard Gendelman, president of the pharmacology and experimental neuroscience division of the UNMC and director of the Center for Neurodegeneration Diseases. The antiretroviral drug is then stored in nanocrystals, which slowly release the drug in which the virus is found.
"We're going to the root cause," Gendelman said. "We are looking for the virus that is already integrated into the genome of the host cell."
The researchers said they used the two treatments simultaneously. First, they administered LASER ART to reduce the growth of HIV, so they used CRISPR treatment as "chemical shears" to "eliminate the DNA residue embedded in the still present HIV," said Gendelman.
The virus did not return to nine of the 21 mice in which the method was tested, according to Khalili.
The authors of the study say the results are promising and are testing the combination of CRISPR-LASER ART on primates. However, there is still a lot of work to be done before the method can be tested on humans.
"The things that work in mice may not work in men," Gendelman said. "The limitations of any mouse work have to do with the species, like the drug we administered, the distribution, which is much easier than a man or a woman."
Gendelman noted that humans are much larger than mice, so there will be many more HIV DNA scientists that they will have to destroy if they test on humans. Khalili also said that steps have yet to be taken to increase the efficiency and safety of the method, but the data from this study "hopefully" that researchers work in primates and are "cautious, but very aggressive" that go on with the tests.
The researchers aim to get approval from the Food and Drug Administration to conduct a phase 1 clinical trial in humans by mid-2020, Khalili said.
Although the study was conducted in mice, Gendelman said that it is still important because it shows that the sterilization of HIV in living animals is possible.
"We are at the peak of a scientific revolution in human genomes that can change the course, quality and longevity of life," said Gendelman.
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