Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists discover what drives the development of a fatal form of malaria

20.08.2008
The culprit: one's own immune system

Platelets – those tiny, unassuming cells that cause blood to clot and scabs to form when you cut yourself – play an important early role in promoting cerebral malaria, an often lethal complication that occurs mostly in children.

Affecting as many as half a billion people in tropical and subtropical regions, malaria is one of the oldest recorded diseases and the parasite responsible for it, Plasmodium, among the most studied pathogens of all time. Still, cerebral malaria, which results from a combination of blood vessel and immune system dysfunction, is not well understood.

In a study described in the August 14 issue of Cell Host and Microbe, Johns Hopkins researchers reveal that when red blood cells are infected with the malaria parasite, they activate platelets to secrete the PF4 protein, which triggers the immune system to inflame blood vessels and obstruct capillaries in the brain; both are hallmarks of cerebral malaria.

In their experiments, the Hopkins team first infected human red blood cells in culture with the malaria parasite and found that this did, indeed, induce platelet activation.

The researchers then infected separate sets of live mice with the malaria parasite: one set treated so that it lacked platelets altogether and two others treated with aspirin or Plavix, platelet inhibitors that prevent the release of PF4.

The survival rate of mice without platelets as well as those treated with inhibitors was improved over that of the mice left alone, but only when the treatment began very soon after infection. When researchers started treating mice with platelet inhibitors one day after infecting them, those mice survived more often than control mice. However, when researchers waited until after three days to treat infected mice with platelet inhibitors, that group did no better in terms of survival.

"Cerebral malaria is lethal 20 percent of the time in the best of hands, and here we've shown that something as simple as aspirin, because of its affect on platelets, might be able to improve the outcomes of those who contract this deadly form of the disease," says David Sullivan M.D., an associate professor of molecular microbiology and immunology in the Johns Hopkins University Bloomberg School of Public Health.

To make the specific connection between PF4 and malaria, the scientists compared the responses to malaria infection by so-called "wild type" normal mice and mice genetically engineered to lack pF4. They found that the amount of parasite in the blood was the same in both sets of mice. The notable difference was in the animals' immune responses to that same parasite burden. More than 60 percent of the mice lacking PF4 were still alive after day 10, while only 30 percent of the mice with PF4 survived that long.

"The take-home lesson is that platelets, by releasing PF4, are playing an early role in the wind-up phase of cerebral malaria," says Craig Morrell, DVM, Ph.D., an assistant professor of molecular and comparative pathobiology at the Johns Hopkins University School of Medicine. "Our mouse studies show that timing is critical; with the mice, we know when we infected them and controlled when we treated them. A big challenge in translating this to humans is that people don't know when they get infected.

"Platelets don't get any respect, but they're the second most abundant cell in the blood after red blood cells and packed full of factors that rally the immune system to action. By taking what we know about platelets and their activation and applying it to malaria, we have found a driver of cerebral malaria."

Beth Simpkins | EurekAlert!
Further information:
http://www.jhmi.edu

More articles from Life Sciences:

nachricht Identifying the blind spots of soil biodiversity
04.08.2020 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht AI & single-cell genomics
04.08.2020 | Helmholtz Zentrum München - German Research Center for Environmental Health

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: AI & single-cell genomics

New software predicts cell fate

Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

Im Focus: NYUAD astrophysicist investigates the possibility of life below the surface of Mars

  • A rover expected to explore below the surface of Mars in 2022 has the potential to provide more insights
  • The findings published in Scientific Reports, Springer Nature suggests the presence of traces of water on Mars, raising the question of the possibility of a life-supporting environment

Although no life has been detected on the Martian surface, a new study from astrophysicist and research scientist at the Center for Space Science at NYU Abu...

Im Focus: Manipulating non-magnetic atoms in a chromium halide enables tuning of magnetic properties

New approach creates synthetic layered magnets with unprecedented level of control over their magnetic properties

The magnetic properties of a chromium halide can be tuned by manipulating the non-magnetic atoms in the material, a team, led by Boston College researchers,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

First radio detection of an extrasolar planetary system around a main-sequence star

04.08.2020 | Physics and Astronomy

The art of making tiny holes

04.08.2020 | Physics and Astronomy

Early Mars was covered in ice sheets, not flowing rivers

04.08.2020 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>