Researchers from Linköping University in Sweden were able to detect the cells needed for fever to occur in the blood vessels of the brain.
The study, which was conducted on mice, was published in the Proceedings of the National Academy of Sciences (PNAS) last October, and the website "EurekAlert" wrote about it, and answered the question that has been posed for a long time: What organ is responsible for causing the fever?
Fever is a body temperature that is higher than the normal temperature that varies from person to person, but it is usually around 37 degrees Celsius.
Fever is the body's response to infection
Fever is the body's response to infection and inflammation, and is the body's way of defending against bacteria and viruses.
When the body is exposed to infection or inflammation, it responds by releasing molecules called cytokines into the bloodstream, and these molecules are too large to cross the blood-brain barrier.
The blood-brain barrier is a network of capillaries that protect the brain from substances that may cause brain damage.
The outer surface of the blood-brain barrier contains receptors that detect cytokines, and these receptors pass the signal to cells on the inner surface of the blood vessel walls in the blood-brain barrier, known as endothelial cells, and then begin to produce a molecule similar to the hormone prostaglandin "E2" (E2), Which in turn activates receptors in the hypothalamus, which regulate body temperature, triggering a fever. However, it is not yet clear if this is the only mechanism behind the fever.
It was previously thought that prostaglandins must also be produced in certain cells of some organs such as the liver and lungs in order to initiate the fever reaction, but researchers at Linköping University have shown that this is not the case, as it turns out that only the endothelial cells of the brain are required to produce the fever reaction.
old question
"Our results answer a question that has been asked for decades. There has never been any evidence that only endothelial cells in the brain are needed to initiate a febrile reaction," says Anders Blomqvist, a professor at Linköping University.
The researchers worked with genetically modified mice, removing some of the genes that code for the production of prostaglandins in the endothelial cells of the brain. Then, they injected the mice with substances found in the cell walls of certain bacteria, which produced a fever in this way. The genetically modified mice did not show any fever reaction after the injection.
This allowed the researchers to conclude that these endothelial cells were necessary to cause fever, but it did not appear if they were sufficient.
For this reason, the researchers tested another genetically modified mouse model in which the only cells that could produce prostaglandin E2 were the endothelial cells of the brain. These mice showed a fever reaction, confirming that the endothelial cells in the brain were already sufficient.
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