Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Methamphetamine increases susceptibility to deadly fungal infection

30.07.2013
Methamphetamine use can make a person more susceptible to the lung infection cryptococcosis, according to a study published in mBio®, the online open-access journal of the American Society for Microbiology.

Researchers found that injected methamphetamine (METH) significantly enhanced colonization of the lungs by Cryptococcus neoformans and accelerated progression of the disease and the time to death in mouse models.

C. neoformans is usually harmless to healthy individuals, but METH causes chinks in the blood-brain barrier that can permit the fungus to invade the central nervous system, where it causes a deadly brain infection.

"The highest uptake of the drug is in the lungs," says corresponding author Luis Martinez of Long Island University-Post, in Brookville, New York and of Albert Einstein College of Medicine in The Bronx. "This may render the individual susceptible to infection. We wanted to know how METH would alter C. neoformans infection."

Thirteen million people in the US have abused METH in their lifetimes, and regular METH users numbered approximately 353,000 in 2010, the most recent year for which data are available. A central nervous system stimulant that adversely impacts immunological responses, recent studies show that injected METH accumulates in various sites in the body, but the lungs seem to accumulate the highest concentrations, says Martinez, which could well impact how the lung responds to invading pathogens.

To study the impact this accumulation might have on pulmonary infection, Martinez and his colleagues injected mice with doses of METH over the course of three weeks, then exposed those mice to the C. neoformans fungus. In humans, C. neoformans initially infects the lungs but often crosses the blood-brain barrier to infect the central nervous system and cause meningitis. In their experiments, METH significantly accelerated the speed with which the infected mice died, so that nine days after infection, 100% of METH treated mice were dead, compared to 50% of the control mice.

Using fluorescent microscopy to examine lung tissue in METH-treated and control mice, the researchers found that METH enhanced the interaction of C. neoformans with epithelial cells in the lining of the lung. Seven days after exposure to the fungus, the lungs of METH-treated mice showed large numbers of fungi surrounded by vast amounts of gooey polysaccharide in a biofilm-like arrangement. METH-treated mice also displayed low numbers of inflammatory cells early during infection and breathed faster than controls, a sign of respiratory distress.

Martinez says this greater ability to cause disease in the lung may be due in part to simple electrical attraction. Their analysis shows that METH imparts a greater negative charge on the surface of the fungal cells, possibly lending them a greater attraction to the surface of the lung and an enhanced ability to form a biofilm that can protect its members from attack by the immune system. The fungus also releases more of its capsular polysaccharide in METH-treated mice, which can help the organism colonize and persist in the lung.

"When the organism senses the drug, it basically modifies the polysaccharide in the capsule. This might be an explanation for the pathogenicity of the organism in the presence of the drug, but it also tells you how the organism senses the environment and that it will modify the way that it causes disease," Martinez says.

But the fungus doesn't stop in the lungs. "The drug stimulates colonization and biofilm formation in the lungs of these animals," says Martinez. "And this will follow to dissemination to the central nervous system by the fungus."

C. neoformans in the lung moved on to the bloodstream and then into the central nervous system. The brains of METH-treated mice had higher numbers of C. neoformans cells, greater quantities of the fungus' polysaccharide, and larger lesions than control mice, indicating that METH has a detrimental effect on the blood-brain barrier, permitting the pathogen to cross more easily from the bloodstream to infect the central nervous system.

"METH-induced alterations to the molecules responsible to maintain the integrity of the blood-brain barrier provide an explanation for the susceptibility of METH abuser to brain infection by HIV and other pathogens," write the authors.

Martinez and his colleagues plan to follow up on the work by investigating how aspects of the immune system might be involved in changes the drug causes to the blood-brain barrier.

mBio® is an open access online journal published by the American Society for Microbiology to make microbiology research broadly accessible. The focus of the journal is on rapid publication of cutting-edge research spanning the entire spectrum of microbiology and related fields. It can be found online at http://mbio.asm.org.

The American Society for Microbiology is the largest single life science society, composed of over 39,000 scientists and health professionals. ASM's mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.

Jim Sliwa | EurekAlert!
Further information:
http://www.asmusa.org
http://mbio.asm.org

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | 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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>