Severe COVID-19 can cause damage to the brain stem, or brain control center, affecting vital functions such as breathing and causing persistent symptoms such as fatigue, anxiety and breathing difficulties.
Damage to the brainstem, known as the brain’s “control center,” is behind the lasting physical and psychiatric effects in patients who have suffered a severe SARS-CoV-2 coronavirus infection, a new study by researchers suggests. researchers from the universities of Cambridge and Oxford, who managed to identify the harmful effects that Covid-19 can cause on the brain using ultra-high resolution scanners capable of observing the brain in great detail.
The research team scanned the brains of 30 people who had been hospitalized with severe COVID-19 early in the pandemic, before vaccines were available. They discovered that the infection affects an area of the brain stem related to feelings of shortness of breath, fatigue and anxiety.
The MRI scanners used in the study, known as 7-Tesla (7T) scanners, can measure inflammation in the brain. The results have been published in the journal Brain and will allow scientists and doctors to better understand the long-term impact of COVID-19 on both the brain and the rest of the body. Although the study began before these long-term effects of Covid were recognized, its findings will help better understand this condition.
Inflammation in the brain control center after COVID
The brainstem, which connects the brain to the spinal cord, is crucial for many vital functions such as breathing and heart rate. Within this structure, nuclei, which are clusters of nerve cells, regulate essential body functions such as breathing, pain, and blood pressure.
Dr. Catarina Rua, a member of the Department of Clinical Neurosciences at the University of Cambridge and lead author of the study, said that observing inflammation in brainstem nuclei in living people was difficult until now due to the small size and position of these nuclei, so studies on this area were done in autopsies.
For his part, Professor James Rowe, co-leader of the study, explained that the brain stem is the critical connection between our conscious actions and what happens in our bodies. Being able to observe how this area changes due to COVID-19 is key to understanding and treating its lasting effects.
In the early days of the pandemic, postmortem studies of people who died from serious infections showed changes in the brain stem, such as inflammation. Many of these changes are thought to have been due to the immune response following infection, rather than a direct invasion of the virus into the brain.
“Changes in the brain stem caused by COVID-19 infection could also lead to poor mental health outcomes, due to the close connection between physical and mental health”
Rowe noted that people who were seriously ill at the beginning of the pandemic had lasting changes in the brain, likely due to this immune response. However, measuring this response in living people is difficult. Conventional MRI scanners do not offer the necessary level of detail, but 7T scanners do detect the activity of immune cells, which interfere with the ultra-powerful magnetic field.
Many patients hospitalized early in the pandemic reported persistent symptoms such as fatigue, shortness of breath, and chest pain. The researchers hypothesized that these symptoms were due, in part, to damage to the nuclei of the brain stem, damage that persists long after the infection has cleared.
The study revealed that several areas of the brain stem, such as the medulla oblongata, pons, and midbrain, had abnormalities that suggested a neuroinflammatory response. These abnormalities appeared weeks after hospitalization and affected the areas of the brain responsible for breathing.
Rua explained that the presence of abnormalities in areas associated with breathing indicates that prolonged symptoms are due to inflammation in the brain stem after infection. This effect was observed regardless of age or gender, being more marked in those who had severe COVID-19.
In addition to the physical effects, the 7T scans also showed some of the psychiatric impacts of the disease. The brain stem regulates breathing, fatigue and anxiety. “Mental health is closely related to brain health and patients with the strongest immune response also showed higher levels of depression and anxiety,” Rowe said. “Brainstem changes caused by COVID-19 infection could also lead to poor mental health outcomes, due to the close connection between physical and mental health,” Rowe added, noting that patients with higher immune response also showed higher levels of depression and anxiety.
These results could help understand other diseases related to brain stem inflammation, such as multiple sclerosis and dementia. They could also be used to evaluate the effectiveness of treatments for brain diseases. Rua concluded by expressing his astonishment at how this collaboration was carried out at the height of the pandemic, when testing was very difficult to perform, and highlighted the value of the 7T scanners in research.
