Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Antibiotic might fight HIV-induced neurological problems

29.04.2005


By studying animals, Johns Hopkins researchers have discovered that the antibiotic minocycline might help alleviate HIV’s negative effects on the brain and central nervous system, problems that can develop even though antiretroviral therapy controls the virus elsewhere in the body.



Five monkeys infected with simian immunodeficiency virus (SIV), a very close relative of HIV, and treated with minocycline had less damage to brain cells, less brain inflammation, and less virus in the central nervous system than six infected monkeys that received no treatment, the researchers report in the April 27 issue of the Journal of the American Medical Association.

"In people, antiretroviral treatments do a great job of controlling HIV in blood, but most of the drugs don’t cross the blood-brain barrier very well," says Christine Zink, D.V.M., Ph.D., professor of comparative medicine at the Johns Hopkins University School of Medicine. "As a result, even though the infection seems to be controlled, it may still cause damage in the brain. And because people are living with HIV longer than ever, the prevalence of neurological damage is increasing. Currently, there’s no drug to treat it directly."


In use for more than 30 years, minocycline was specifically designed to cross the blood-brain barrier, the biological "wall" that limits what can pass from the blood into the brain. Other researchers have reported that this antibiotic can protect brain cells in animal models of other diseases -- multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer’s disease, stroke and more. The drug is being tested in early clinical trials for some non-HIV-related conditions.

"Last year we discovered that SIV triggers some of the same biological pathways of cell death and inflammation as these other diseases," says Sheila Barber, Ph.D., assistant professor of comparative medicine. "Testing minocycline in our animal model of HIV infection was really a logical next step."

A multicenter clinical trial is being planned to test whether minocycline has the same effects in HIV-infected people as it does in SIV-infected monkeys, but it is not expected to start until sometime next year.

"It is too early to recommend minocycline for patients," emphasizes Ned Sacktor, M.D., an associate professor of neurology at the Johns Hopkins Bayview Medical Center who wasn’t involved with the current study, but who is one of the physicians planning the clinical trial. "One needs to proceed with a clinical research trial first to prove its safety and efficacy against HIV-associated cognitive impairment."

SIV and HIV both affect the same tissues in the same way and use the same tricks to infect cells and outwit treatments, but SIV infects only non-human primates, and HIV only infects people. Antiretroviral drugs target and interfere with the viral proteins needed to accomplish this.

In contrast, minocycline doesn’t target the virus or its proteins. While they’re still working out the details, the researchers have shown that minocycline "calms down" as yet undefined biological pathways that involve two specific proteins -- MCP-1 and p38 -- implicated in damage in neurodegenerative diseases.

The MCP-1 protein, when secreted from brain cells under attack from HIV or SIV, attracts infection-fighting cells known as macrophages, which then enter the brain. The influx of these cells contributes to swelling and inflammation known as encephalitis. The other protein, p38, helps trigger a series of events that result in a cell’s programmed death, called apoptosis.

Only one of the five treated monkeys showed any signs of encephalitis, and that monkey’s condition was deemed mild by a set of standard measures. After the same amount of time -- 84 days after infection -- five of the six untreated monkeys had evidence of moderate or severe encephalitis and much more physical evidence of damage to brain cells, the researchers report.

"The infection in the animal model is predictable and aggressive, so we can get meaningful data by studying fewer animals," says Zink, who was on the team that developed the model about six years ago. "It’s a really demanding test of a potential treatment for HIV."

The animal model has already helped improve understanding of how HIV might affect the brain, and this is the first time it’s been used to test a potential treatment. Studies with the animals are augmented by laboratory experiments with cells to clarify observations.

Notably, these laboratory experiments have shown that minocycline somehow suppresses replication of HIV and SIV in macrophages -- the immune cells recruited to the brain during HIV infection -- and lymphocytes -- immune cells that carry "sleeping" HIV and SIV even when antiretroviral treatment is effective.

"If this preliminary observation holds up, minocycline could be really important for treating HIV infection in developing countries where access to traditional antiretroviral drugs is very limited," says Zink. "Most of the 40 million people with HIV infection live in these countries."

Joanna Downer | EurekAlert!
Further information:
http://www.jhmi.edu

More articles from Health and Medicine:

nachricht NTU scientists build new ultrasound device using 3-D printing technology
07.12.2016 | Nanyang Technological University

nachricht How to turn white fat brown
07.12.2016 | University of Pennsylvania School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Silicon solar cell of ISFH yields 25% efficiency with passivating POLO contacts

08.12.2016 | Power and Electrical Engineering

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>