Wednesday , October 5 2022

Toxoplasmosis parasite changes our synaptic brain


Many people get infected: the toxoplasmosis parasite transforms into the synapse in the brain

Pets are a great job for most people. But some of the four-legged friends can carry the disease. For example, toxoplasmosis, an infectious disease, the pathogen that is commonly found in feline faeces. Researchers have now shown how the toxoplasmosis parasite regenerates the synapse in the brain.

One of the most common infectious diseases

A few years ago, US scientists reported that some cat owners had greater aggression and instability. Those who were infected with Toxoplasma gondii. The worldwide single-digit parasite causes one of the most common infectious diseases, toxoplasmosis.

Viencelled parasite Toxoplasma gondii infects birds and mammals, including humans. However, his final owners are cats. For some people, the pathogen can be dangerous. (Image: alho007 /

The single-parasite infects birds and mammals

Viencelled parasite Toxoplasma gondii infects birds and mammals, including humans. However, his final owners are cats.

Researchers from the Otto von Guericke University in Magdeburg (OVGU) and the Institute of Infectious and Neurodegenerative Studies at the Leibniz Institute of Neurobiology (LIN) studied how parasites affect metabolism in the brain of its hosts and have shown that it changes the molecular composition of the synapse.

Scientists' results were published in the journal Journal of Neuroinflammation.

The disease usually remains unnoticed

According to a report published by the Informationsdienst Wissenschaft (IDW), about 30-50 percent of all people already have been infected with toxoplasm in their lifetime. For those over 50, they even face about 50 percent.

Most of the toxoplasmosis remains unnoticed and the infected do not suspect that they are infected.

"In healthy people, the infection causes short-term cold symptoms, such as chills, fever and bodily pain," Prof. Dr. med Ildiko Rita Dunay, Director of the Institute of Inflammation and Neurodegeneration of OVGU.

"Such an infection can be dangerous for pregnant women or for people with a weakened immune system. There is no therapy to get rid of the parasite when it attacks the brain. So when you are infected, it's a long time," says an expert.

Another problem is that neonatal toxoplasmosis is often not revealed, as reports by the Robert Koch Institute (RKI) reported by the journalist "Scientific reports."

The parasite is absorbed by humans through digestion

The parasite is nesting in the muscle tissues of infected animals, but not only:

"Toxoplasma gondii is absorbed by the digestive process, it enters the bloodstream, as well as migrates to the brain where they live in nerve cells," says Dr. Med. Karl-Heinz Smalla from LIN's Special Lab for Molecular Biologicals.

Previous studies by other German researchers have shown that toxoplasmosis in the brain can have serious long-term effects.

Even Magdeburg scientists have previously found experiments with mice that infected animals of Toxoplasma gondii come up with surprising behavioral changes:

"Mice that are cats looting have lost their natural fear of cats after the infection, and if rodents were presented with a smell of cat urine, they even seemed to have preferred cats," said researchers.

Therefore, in order to explain these behavioral changes, they studied the changes in the foot brain, in particular the synaptic molecular composition, as they are the main signal processing structures in the brain.

In collaboration with the Helmholtz Infectious Disease Research Center in Braunschweig, they were able to prove that, together with 300 synaptic proteins, the levels of infection in the brain have changed in the brain after a toxoplasmosis.

In particular, proteins were particularly reduced in glutamate-releasing exciting synapses. On the other hand, there is an increased level of protein involved in immune responses.

Improved immune response

Sulfidiazine is commonly used to treat toxoplasmic infections, which partially inhibits the spread of toxic diseases.

Psychiatrist and neuroscientist Björn Schott explains: "Now we wanted to know how sulfadiazine treatment is affected by the molecular changes in the brain caused by the infection."

Result: The protein content of the mouse brain after treatment was comparable to the protein content of non-infected species.

"All tested proteins responsible for transmitting the glutamaterge signal were again in the normal range, and the inflammatory activity also decreased measurably."

It appears that the infection causes an increased immune response that reduces the amount of protein involved in causing glutamate-induced synapse, while sulfadiazine reduces the toxoplasma and thus normalizes the immune response, thereby leading to the re-emergence of synaptic proteins.

Opinions may also be important to people

These discoveries can also be medically important for humans.

"They support the suggestion that Toxoplasma gondii is a risk factor for neuropsychiatric disorders," said the neuroscientist Dunay.

"Glutamaterial synapses are associated with the causes of depression, schizophrenia and autism, and the immune response components point to these diseases," explains the expert.

"This suggests that an immune response can lead to synaptic changes that can lead to neuropsychiatric disorders." (Ad)

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