Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Green tea extract protects against brain damage in new mouse model of HIV-related dementia

02.05.2007
A compound derived from green tea greatly diminished the neurotoxicity of proteins secreted by the human immunodeficiency virus, suggesting a new approach to the prevention and treatment of HIV-associated dementia, also known as AIDS dementia complex. The disorder is the most severe form of HIV-related neuropsychiatric impairment.

University of South Florida neuroscientist Brian Giunta, MD, reported the findings May 1 at Experimental Biology 2007 in Washington, DC. His presentation was part of the scientific program of the American Society for Pharmacology and Experimental Therapeutics. The study was conducted using a new mouse model for HIV-related dementia developed by Dr. Giunta and Jun Tan, MD, PhD, director of the Neuroimmunology Laboratory at the Silver Child Development Center, USF Department of Psychiatry,

"These findings suggest that EGCG, the green tea-derived compound, may represent a new and natural compound for the prevention and treatment of this devastating disease," Dr. Giunta said.

"This is a very important finding in the prevention and treatment of HIV-related dementia, which is usually observed in the late stages of HIV disease," said Abdul S. Rao, MD, MA, DPhil, senior associate vice president for USF Health and vice dean for research and graduate affairs at the College of Medicine. "The neuroprotective effects of EGCG, the green-tea extract, may offer an alternative to existing mono or combination antiretroviral therapies that are known to have poor central nervous system penetration."

... more about:
»Cytokine »EGCG »Giunta »HIV »HIV proteins »HIV-related »dementia

HIV-associated dementia, a debilitating cognitive, emotional, and physical disorder, affects 22 percent of HIV-infected adults and more than half of HIV-infected children. Symptoms often begin with slight changes in behavior, intellectual ability, memory, and muscle coordination. Some patients experience depression-like symptoms such as loss of appetite and motivation. Tasks requiring complex thinking and high concentration become difficult, and motor skills gradually deteriorate over time.

The highly active antiretroviral therapies used in developed nations appear to slow the development of brain damage in patients with HIV-related dementia, making it a protracted disorder rather than an acute one. Unfortunately, these therapies neither cure nor prevent development of HIV-associated dementia and several epidemiologic studies indicate they increase the prevalence of the dementia. Currently, no treatments specifically target this neuropsychiatric disorder.

HIV-associated dementia is believed to be caused by the direct effects of HIV upon the brain. The virus secretes proteins known as Tat and gp120, which have direct toxic effects on the neurons. The proteins also have indirect effects caused by the release of chemical messengers known as cytokines, which interact with the HIV proteins to cause death of the brain cells. High levels of these cytokines alone also are toxic to the brain.

When healthy mice were given doses of the HIV proteins Gp120 and/or Tat, in combination with a cytokine known as interferon-gamma, they developed brain damage closely resembling that seen in HIV-associated dementia in humans. Dr. Giunta said the finding may help explain the cognitive and behavioral changes in individuals infected with HIV.

Dr. Giunta then used epigallocatechin-3-gallate (EGCG), the major antioxidant derived from green tea, to break into this pathway of neurotoxicity. He was successful both in cell studies and in studies involving the new mouse model of the disease.

Cultured neurons from mice were exposed to EGCG before being given a cocktail of the two neurotoxic HIV proteins and the toxic cytokine. The green tea compound inhibited the ability of the cytokine to act with the HIV proteins to cause death and damage of the neurons. In further confirmation, the green tea compound also inhibited the neurotoxic properties of these HIV proteins in the presence of the cytokine in live mice.

Anne DeLotto Baier | EurekAlert!
Further information:
http://www.usf.edu

Further reports about: Cytokine EGCG Giunta HIV HIV proteins HIV-related dementia

More articles from Life Sciences:

nachricht New photocatalyst speeds up the conversion of carbon dioxide into chemical resources
29.05.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

nachricht Copper hydroxide nanoparticles provide protection against toxic oxygen radicals in cigarette smoke
29.05.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>