“We are taking a first step towards specific treatments for coma recovery”

“At European level, per year, there are around 300,000 patients in coma after cardiac arrest, and half a million after head trauma. Every year, we have around a hundred thousand patients in Europe who survive”, explains Professor Stein Silva, resuscitation doctor at Toulouse University Hospital, professor at Toulouse III University – Paul Sabatier, and researcher within the ToNIC and PUPH intensive care unit at Toulouse University Hospital. But these people who emerge from the coma regain consciousness more or less well and many present handicaps: “these visible disabilities are greater than those of all causes of dementia combined, including Alzheimer’s disease, in Europe at least”.

Understanding the underlying mechanisms of coma is therefore a real public health issue. “Research in this area is very active, there have been studies where certain avenues and certain medications have been tested, but to date, none have shown their effectiveness in terms of facilitating the return to consciousness.”, adds the Professor, who presents the very encouraging results of his new work carried out with Dr Benjamine Sarton, resuscitation doctor at Toulouse University Hospital and researcher within the ToNIC unit (Inserm/UT3). The complete study will be published on March 28 in the BRAIN magazine.

Coma: the key role of inflammation in “repairing” patients’ brains

“The state of coma corresponds to the rapid and complete abolition of consciousness following an
severe brain injury”, recalls in the preamble the researchers’ press release. “The most severe form of acute alteration of consciousness, it is a major public health problem, because it is associated with significant mortality and variable levels of recovery, often responsible for significant neurological disabilities.”

In general, coma results from a traumatic brain attack (head trauma for example) or an anoxic brain attack (i.e. following cardiac arrest). “The care of these patients is fairly standardized and mainly centered around maintaining vital functions, while awaiting recovery. spontaneous neurological”, explain the researchers.

To carry out their work, the researchers relied on the analyzes of 17 patients treated in different departments of the Toulouse University Hospital (Purpan multipurpose intensive care unit, Rangueil intensive care unit, neurosurgical intensive care unit, intensive cardiology care), all benefiting from assistance. heavy vital functions (intubation and on an artificial respirator). Among them, 11 were in a coma following a traumatic accident; and 6 were following anoxia.

“Using innovative in vivo molecular imaging methods carried out by positron emission imaging (PET Scan), the Toulouse team was able to observe for the first time the levels of brain inflammation in coma patients and compare them to those of healthy people. These observations made it possible to highlight the importance of the role of cerebral inflammation during coma, thus opening a new area of ​​research with potentially major medical repercussions on patients in coma.”

Predicting Chances of Recovery from Severe Brain Injury

Thanks to these tests carried out between 2018 and 2022, researchers made several discoveries. First, the research group identified significant levels of brain inflammation in areas of the brain involved in conscious information processing. “This made it possible to highlight lesion processes that could potentially be modulated using appropriate treatments, they explain. This result could constitute a major paradigm shift in the field.”

Furthermore, they realized that the profiles of brain inflammation are not the same in patients in coma of traumatic or anoxic origin, both in terms of intensity and location. “This could provide a better understanding of the great heterogeneity of recovery profiles observed in this context.”, underline the scientists, who add that “these imaging methods can be used for prognostic evaluation of patient recovery, depending on the areas affected by brain inflammation”.

Thus, these results could help medical teams predict a patient’s chances of recovery after a severe brain injury, and “guide clinical trials aimed at modulating the immune activity of the brain, in particular through pharmacological means”.

“There is still a long way to go, but it is really a concrete hope now”

“Finding the inflammation is a real hope”, exclaims researcher Professor Silva. “Because we can imagine that among the myriad of drugs that we currently have that can treat inflammation in other diseases, we could have some that are effective in reducing this inflammation in patients in a coma. and therefore improve recovery. We are taking a first step towards specific treatments for coma recovery.”

What next to expect now? “We continue to do research, again with these images, but we will also study the markers in the blood to try to better understand what type of inflammation is involved in these contexts, enthuses the researcher. And the next step is to test the drugs! So we’re still a few years away from getting there, there’s still a long way to go, but it’s really a concrete hope now.”