NANOTECH INNOVATIONS

In a breakthrough that could potentially lead to a cure for HIV infection, scientists have discovered a way to remove the virus from infected cells.

The scientists engineered an enzyme which attacks the DNA of the HIV virus and cuts it out of the infected cell, according to a study published today in the U.S. journal Science.

The enzyme is still far from being ready to use as a treatment, the authors warned, but it offers a glimmer of hope for the more than 40 million people infected worldwide.

Cut it out

“A customized enzyme that effectively excises integrated HIV-1 from infected cells in vitro might one day help to eradicate (the) virus from AIDS patients,” Alan Engelman, of Harvard University’s Dana-Farber Cancer Institute, in Boston, U.S., wrote in an article accompanying the study.

Current treatments focus on suppressing the HIV virus in order to delay the onset of AIDS and dramatically extend the life of infected patients. What makes HIV so deadly, however, is its ability to insert itself into the body’s cells and force those cells to produce new infection.

“Consequently the virus becomes inextricably linked to the host, making it virtually impossible to ‘cure’ AIDS patients of their HIV-1 infection,” Engelman explained.

That could change if the enzyme developed by a group of German scientists can be made safe to use on people. That enzyme was able to eliminate the HIV virus from infected human cells in about three months in the laboratory.

The researchers engineered an enzyme called Tre which removes the virus from the genome of infected cells by recognizing and then recombining the structure of the virus’s DNA.

This ability to recognize HIV’s DNA might one day help overcome one of the biggest obstacles to finding a cure: the ability of the HIV virus to avoid detection by reverting to a resting state within infected cells which then cease to produce the virus for months or even years.

“Proof of principle”

“Numerous attempts have been made to activate these cells, with the hope that such strategies would sensitise the accompanying viruses to antiviral drugs, leading to virus eradication,” Engelman wrote. “Advances with such approaches in patients have been slow to materialize.”

New experiments must be designed to see if the Tre enzyme can be used to recognize these dormant infected cells, he wrote.

“Although favourable results would represent perhaps only a baby step toward eventual use in patients, the discovery of the Tre recombinase proves that enzymatic removal of integrated HIV-1 from human chromosomes is a current-day reality,” he said.

The researchers who developed the enzyme were optimistic about their ability to design additional enzymes which would target other parts of the virus’s DNA.

However they warned that there were significant barriers to overcome before the enzyme could be used to help cure patients.

“The most important, and likely most difficult, among these is that the enzyme would need efficient and safe means of delivery and would have to be able to function without adverse side effects,” wrote lead author Indrani Sarkar of the Max Planck Institute for Molecular Cell Biology and Genetics in Dresden.

“Nevertheless the results we present offer an early proof of principal for this type of approach, which we speculate might form a useful basis for the development of future HIV therapies,” Sarkar concluded.

A report presented at the 20th Conference on Retroviruses and Opportunistic Infections describes how an HIV-infected infant underwent remission after receiving antiretroviral therapy (ART) within 30 hours of birth.

A team of researchers from Johns Hopkins Children’s Center, the University of Mississippi Medical Center and the University of Massachusetts Medical School describe the first case of a so-called “functional cure” in an HIV-infected infant. The finding, the investigators say, may help pave the way to eliminating HIV infection in children.

A report on the case is being presented on Sunday, March 3, at the 20th Conference on Retroviruses and Opportunistic Infections (CROI) in Atlanta. Johns Hopkins Children’s Center virologist Deborah Persaud, M.D., lead author on the report, and University of Massachusetts Medical School immunologist Katherine Luzuriaga, M.D., headed a team of laboratory investigators. Pediatric HIV specialist Hannah Gay, M.D., associate professor of pediatrics at the University of Mississippi Medical Center provided treatment to the baby.

The infant described in the report underwent remission of HIV infection after receiving antiretroviral therapy (ART) within 30 hours of birth. The investigators say the prompt administration of antiviral treatment likely led to this infant’s cure by halting the formation of hard-to-treat viral reservoirs — dormant cells responsible for reigniting the infection in most HIV patients within weeks of stopping therapy.

Researchers coated condoms in microscopic particles of silver — which has long been known to have disinfectant …University of Manitoba medical microbiologist Dr Xiaojian Yao, who specializes in researching the HIV virus, has discovered a potential new way to protect ourselves against HIV and the Herpes virus: silver nanoparticles.

He and his team coated condoms in microscopic particles of silver — which has long been known to have disinfectant properties — and they found that when they brought the silver-coated condoms into contact with HIV and Herpes, both viruses were completely inactivated. Additionally, they discovered that both the T-cell and macrophage strains of HIV, as well as drug-resistant strains, were highly susceptible to the silver nanoparticles, and they also acted to prevent the growth of bacteria and fungi.

Nanoparticle research is being pursued in a number of fields, due to their potential as a bridge between larger, bulk substances and the structures of atoms and molecules.

“At such nanoscale, the extremely small size of silver particles exhibits remarkable, unusual physio-chemical properties and biological activity,” said Yao, according to the National Post.

It’s still unclear exactly how the silver nanoparticles are deactivating the viruses, but the research is still in its beginning stages. According to Yao, the nanoparticles themselves, or silver ions released by them, could be bonding to the viruses or altering ‘key proteins’ on the surface of the virus, preventing them from attaching to their host.

Current efforts to make condoms more effective in preventing STDs has included the use of Nonoxynol-9, which recent studies have shown can actually make infection more likely, due to causing genital inflammation and ulceration. Silver nanoparticles, on the other hand, do not cause inflammation and are, in fact, anti-inflammatory, according to the study. Although some silver ions are toxic, the silver nanoparticles themselves are relatively non-toxic, and since the condoms would be discarded quickly after use, exposure would be limited.

Furthermore, since the mere presence of the nanoparticles inhibits the viruses, bacteria and fungi, and the particles do no wash off, anyone who may handle the condom after use would also likely be protected from any potential infection.

Dr Julio Montaner, the director of the B.C. Centre for Excellence in HIV/AIDS called the research “promising”, according to the National Post, but the major issue with condoms is still whether or not they are used.

“Unfortunately, at the most critical moment when these decisions are so important, people’s judgment may be impaired,” said Dr. Montaner. “At the end of the day, if they stay in the pocket, it’s not going to do the job.”