The course of a stroke was previously described by scientists as follows: A blood vessel supplying the brain with oxygen and vital nutrients is suddenly blocked by a blood clot. This leads to a stroke, causing injury to the brain. As a result, many patients suffer from neurological dysfunctions, such as severe paralysis or speech disorders.
After a stroke, regulatory T cells (green) can be mainly identified in the cerebral vessels (red), where they interact with the vessel wall, clotting the respective blood vessel in the process (upper row of pictures). Accordingly, the cerebral blood flow (lower row of pictures) after a stroke is significantly higher in mice without regulatory T cells (right) than in normal mice (left). For measuring the cerebral blood flow, the animals were examined in an MRI scanner.
Picture: Christoph Kleinschnitz / Heinz Wiendl
"This picture must be supplemented by another important factor, namely the immune system," says Professor Christoph Kleinschnitz, head of stroke medicine at the University of Würzburg's Department of Neurology. He verified this in a joint project with the study group of Professor Heinz Wiendl at the University Hospital of Münster.
Regulatory T cells as culprits
The new insight was discovered in mice the immune system of which lacks regulatory T cells due to a genetic defect: The brain damage sustained by these mice after a stroke is reduced by about 75 percent as compared to normal mice. Furthermore, these mice develop significantly fewer neurological dysfunctions.
Regulatory T helper cells are an important part of the immune system and usually have the task of suppressing excessive immune responses of the body. Due to their regulatory properties, they play a protective role in many diseases, such as multiple sclerosis or rheumatism.
Paradigm shift in immunology
"The fact that regulatory T cells aggravate the brain damage to this extent in acute stroke cases came as a complete surprise to us," reports Heinz Wiendl, Director of the Department of Neurology, Division for Inflammatory Diseases of the Nervous System and Neuro-Oncology at the University Hospital of Münster: "We can say without exaggeration that this constitutes a paradigm shift from the perspective of immunology."
In their research, the immunologists also investigated with which mechanisms the regulatory T cells exacerbate the harmful effect of a stroke. They found out that this cell type interacts with platelets and blood vessel walls, especially in the early stages after a stroke. This worsens the clotting of the cerebral vessels, further reducing the cerebral blood flow.
The next studies
The scientists are now going to determine whether the results can be applied to humans. Should this be the case, strokes might be treated in future with drugs that affect regulatory T cells.
"This would represent a small medical revolution," says Kleinschnitz, for stroke is a widespread disease, having become the second leading cause of death worldwide. Effective therapies are scarce. "It will still take a series of further studies, however, to translate the discovery into an effective drug treatment," Kleinschnitz emphasizes.
Sponsors of the research
The studies were funded by the German Research Foundation (DFG) and by the Else Kröner-Fresenius Foundation. The DFG supported the research via the excellence cluster "Cells in motion" in Münster and the collaborative research center 688 in Würzburg.
"Regulatory T cells are strong promoters of acute ischemic stroke in mice by inducing dysfunction of the cerebral microvasculature", Christoph Kleinschnitz, Peter Kraft, Angela Dreykluft, Ina Hagedorn, Kerstin Göbel, Michael K Schuhmann, Friederike Langhauser, Xavier Helluy, Tobias Schwarz, Stefan Bittner, Christian T Mayer, Marc Brede, Csanad Varallyay, Mirko Pham, Martin Bendszus, Peter Jakob, Tim Magnus, Sven G Meuth, Yoichiro Iwakura, Alma Zernecke, Tim Sparwasser, Bernhard Nieswandt, Guido Stoll, Heinz Wiendl. Blood, published ahead of print November 15, 2012, doi:10.1182/blood-2012-04-426734
Prof. Dr. Christoph Kleinschnitz, Department of Neurology at the University Hospital of Würzburg, T (0931) 201-23756, email@example.com
or Prof. Dr. Heinz Wiendl, Department of Neurology – Division for Inflammatory Diseases of the Nervous System and Neuro-Oncology, University Hospital of Münster, T (0251) 83-46810, firstname.lastname@example.org
Robert Emmerich | Uni Würzburg
Second cause of hidden hearing loss identified
20.02.2017 | Michigan Medicine - University of Michigan
Prospect for more effective treatment of nerve pain
20.02.2017 | Universität Zürich
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
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”...
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...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
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...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
21.02.2017 | Earth Sciences
21.02.2017 | Medical Engineering
21.02.2017 | Trade Fair News