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 Closing the carbon loop
08.12.2016 | University of Pittsburgh

nachricht Newly discovered bacteria-binding protein in the intestine
08.12.2016 | University of Gothenburg

All articles from Life Sciences >>>

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

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>