Platelets play a key role in strokes: They can even drive nerve cells in the brain into a kind of suicide mode, as scientists from the University of Würzburg now report in the journal "Blood".
A stroke typically develops as follows: A blood vessel supplying the brain with vital oxygen and nutrients is blocked by a blood clot, resulting in nerve cell death. Signs and symptoms of a stroke can include inability to move and speech problems.
Platelets are a major constituent of these blood clots. They are small cell fragments that circulate in the blood vessels whose function is to stop bleeding and close wounds.
"Scientists have suspected platelets to play an important role in the development of strokes for quite some time. But their exact function was unknown until recently," says Professor Christoph Kleinschnitz, head of the Stroke Unit of the Department of Neurology of the Würzburg University Hospital.
Detrimental platelet factor
Together with colleagues from Tübingen and Belgium, the Würzburg researchers have now closed this knowledge gap. What's special about their discovery: They found out that platelets are harmful in different phases of the stroke.
In the early phase, the platelets release a special clotting protein called the Von Willebrand factor. As the scientists report in the renowned journal "Blood", this factor promotes clotting in the brain and aggravates the brain damage after a stroke.
Platelets can trigger apoptosis
But platelets are equally significant in the later phase of a stroke. In a further article in "Blood", the research team demonstrates that the platelets subsequently travel from the vessels into the brain tissue where they can directly damage the nerve cells.
"The underlying mechanism is called apoptosis," explains Dr Peter Kraft from the Department of Neurology of the Würzburg University Hospital. This is a kind of suicide programme of the nerve cells. It is activated once the platelets come into contact with the nerve cells. The researchers have proved that platelets are capable of triggering apoptosis in the brain for the first time ever.
Promising antibodies for therapy
"In order to develop new targets for therapy, it is crucial to understand how platelets behave in the various stages of the stroke," Professor Kleinschnitz explains. "We are pinning our hopes on novel antibodies that are capable of suppressing the harmful function of the platelets." In animal models, these antibodies still work even when they are administered as late as one hour after the stroke.
Moreover, the antibodies can mitigate the nerve-damaging effect of the Von Willebrand factor. And they cause the nerve cells to go into suicide mode less frequently. "So antibodies could target different causes of stroke and be beneficial to many patients," Kleinschnitz says. Before translating into actual therapies, however, additional investigations and safety tests will have to be conducted.
Their research was funded by Deutsche Forschungsgemeinschaft (DFG) within the scope of the Würzburg Collaborative Research Center 688.
Two publications in "Blood"
“Platelets induce apoptosis via membrane-bound FasL”, Rebecca I. Schleicher, Frank Reichenbach, Peter Kraft, Anil Kumar, Mario Lescan, Franziska Todt, Kerstin Göbel, Tobias Geisler, Axel Bauer, Marcus Olbrich, Martin Schaller, Sebastian Wesselborg, Lorraine O’Reilly, Sven G. Meuth, Klaus Schulze-Osthoff, Meinrad Gawaz, Xuri Li, Christoph Kleinschnitz, Frank Edlich, and Harald F. Langer, Blood, 31 July 2015, DOI: http://dx.doi.org/10.1182/blood-2013-12-544445
“While not essential for normal thrombosis and hemostasis, platelet-derived von Willebrand factor fosters cerebral ischemia reperfusion injury in mice”, Sebastien Verhenne, Frederik Denorme, Sarah Libbrecht, Aline Vandenbulcke, Inge Pareyn, Hans Deckmyn, Antoon Lambrecht, Bernhard Nieswandt, Christoph Kleinschnitz, Karen Vanhoorelbeke, Simon F. De Meyer, Blood, 24 July 2015, DOI: http://dx.doi.org/10.1182/blood-2015-03-632901
Prof. Dr. Christoph Kleinschnitz, Department of Neurology of the Würzburg University Hospital, Phone: +49 931 201-23756, firstname.lastname@example.org
Robert Emmerich | idw - Informationsdienst Wissenschaft
What the world's tiniest 'monster truck' reveals
23.08.2017 | American Chemical Society
Treating arthritis with algae
23.08.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
23.08.2017 | Life Sciences
23.08.2017 | Life Sciences
23.08.2017 | Physics and Astronomy