Tag: neuroinflammation

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Review Re-evaluates Biomarker for Imaging Neuroinflammation

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Neuroinflammation can lead to serious neurological or psychiatric diseases, for which there is presently one biomarker available for medical imaging to visualise cerebral inflammation. Trouble is, it has been unclear how to interpret this biomarker. Researchers have now found that a large quantity of this protein indicates a large quantity of inflammatory cells, but its presence is not a sign of their overactivation. These results, published in Nature Communications, pave the way for optimal observation of neuroinflammatory processes with other potential biomarkers, and a re-evaluation of prior research.

In the brain, microglial cells play an important role in inflammation and its potential overactivation. They can be ”activated” when dysfunction occurs, phagocytise pathological cells or proteins and even produce protective substances. Currently, in medical imaging, only one marker can be used to locate and measure microglia non-invasively and in vivo: the TSPO protein, which is present in these cells. This protein can be observed by Positron Emission Tomography (PET), a common imaging technique.

A TSPO of insight

”Hundreds of studies have used PET scans of this protein to explore and quantify microglia. However, no study has succeeded in precisely interpreting the significance of its quantity in the context of an inflammatory reaction,” explains Stergios Tsartsalis, senior clinical associate in the Department of Psychiatry at the UNIGE Faculty of Medicine. Together with other researchers, Stergios Tsartsalis sought to determine if a large quantity of TSPO correspond to a large quantity of inflammatory cells, and whether it is a sign of their overactivation.

The international research team worked on the brains of mouse models of Alzheimer’s disease, amyotrophic lateral sclerosis and multiple sclerosis, and on post-mortem brain samples from patients affected by the same diseases. ”We discovered that a high density of TSPO protein is indeed an indicator of a high density of microglia. On the other hand, the observation of TSPO does not allow us to say whether or not the inflammatory cells are overactivated,” explains the UNIGE researcher, co-first author of the study.

Re-reading the past, optimising the future

This discovery highlights the value of medical imaging of TSPO: it makes it possible to identify cases where the neuroinflammatory disease is linked to a deregulation in the number of glial cells. In addition, the scientists have identified two markers of the state of microglia activation in humans – the LCP2 and TFEC proteins – setting the stage for new medical imaging approaches.

”These results represent a further step towards understanding the role of microglia in neuroinflammation. They will help to optimise the focus of future studies and also to review the conclusions of previous research,” enthuses Stergios Tsartsalis.

Source: Université de Genève

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Hyperbaric Therapy Reduces Neuroinflammation in Autism

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Image by Fakurian Design on Unsplash

A new study at Tel Aviv University showed significant improvements in social skills and the condition of the autistic brain through hyperbaric therapy. The study which is reported in the journal International Journal of Molecular Sciences, was conducted on lab models of autism.

Hyperbaric medicine, where patients sit in special high-pressure chambers while breathing pure oxygen, is considered safe and, besides treating decompression sickness in divers, is already in use for other conditions. The use of hyperbaric medicine to treat autism is contentious, with many holding that it is based on pseudoscience. In recent years, scientific evidence has been accumulating that unique protocols of hyperbaric treatments improve the supply of blood and oxygen to the brain, thereby improving brain function.

Changes observed in the brain included a reduction in neuroinflammation, which is known to be associated with autism. A significant improvement was also found in the social functioning of the animal models treated in the pressure chamber. The study’s success has many implications regarding the applicability and understanding of treating autism using pressure chamber therapy.

The breakthrough was led by doctoral student Inbar Fischer, from the laboratory of Dr Boaz Barak of Tel Aviv University.

Improved brain function

“The medical causes of autism are numerous and varied, and ultimately create the diverse autistic spectrum with which we are familiar,” explains Dr Barak. “About 20% of autistic cases today are explained by genetic causes, that is, those involving genetic defects, but not necessarily ones that are inherited from the parents. Despite the variety of sources of autism, the entire spectrum of behavioural problems associated with it are still included under the single broad heading of ‘autism,’ and the treatments and medications offered do not necessarily correspond directly to the reason why the autism developed.”

In the preliminary phase of the study, a girl carrying the mutation in the SHANK3 gene, which is known to lead to autism, received treatments in the pressure chamber, conducted by Prof Shai Efrati. After the treatments, it was evident that the girl’s social abilities and brain function had improved considerably.

In the next stage, and in order to comprehend the success of the treatment more deeply, the team of researchers at Dr Barak’s laboratory sought to understand what being in a pressurised chamber does to the brain. To this end, the researchers used lab models carrying the same genetic mutation in the SHANK3 gene as that carried by the girl who had been treated. The experiment comprised a protocol of 40 one-hour treatments in a pressure chamber over several weeks.

“We discovered that treatment in the oxygen-enriched pressure chamber reduces inflammation in the brain and leads to an increase in the expression of substances responsible for improving blood and oxygen supply to the brain, and therefore brain function,” explains Dr Barak. “In addition, we saw a decrease in the number of microglial cells, immune system cells that indicate inflammation, which is associated with autism.”

Increased social interest

“Beyond the neurological findings we discovered, what interested us more than anything was to see whether these improvements in the brain also led to an improvement in social behaviour, which is known to be impaired in autistic individuals,” adds Dr Barak. “To our surprise, the findings showed a significant improvement in the social behaviour of the animal models of autism that underwent treatment in the pressure chamber compared to those in the control group, who were exposed to air at normal pressure, and without oxygen enrichment. The animal models that underwent treatment displayed increased social interest, preferring to spend more time in the company of new animals to which they were exposed in comparison to the animal models from the control group.”

Inbar Fischer concludes, “the mutation in the animal models is identical to the mutation that exists in humans. Therefore, our research is likely to have clinical implications for improving the pathological condition of autism resulting from this genetic mutation, and likely also of autism stemming from other causes. Because the pressure chamber treatment is non-intrusive and has been found to be safe, our findings are encouraging and demonstrate that this treatment may improve these behavioral and neurological aspects in humans as well, in addition to offering a scientific explanation of how they occur in the brain.”

Source: Tel Aviv University