New study reveals possible brain mechanisms behind COVID-19 delirium
Researchers from King’s College London have shown that when brain cells are directly exposed to blood taken from COVID-19 patients with delirium, there is an increase in cell death and a decrease in the generation of new brain cells. Delirium represents a state of confusion indicating that, in these patients, the COVID-19 infection had impacted the brain.
Published in Molecular Psychiatry, the study’s findings indicate a key role for the inflammatory proteins (cytokines) produced by the immune system during infection and could help inform potential treatments to reduce symptoms of confusion, disorientation and memory deficits in COVID-19 patients.
The study collected serum samples from 36 patients admitted to Guy's and St Thomas' NHS Foundation Trust, in London, during the first wave of the COVID-19 pandemic in the UK (March-June 2020). Half of these patients were experiencing delirium symptoms whilst the other half did not present with these symptoms at time of hospital admission.
Researchers used a validated in vitro human cell model that consists of cells from the hippocampus, a part of the brain fundamental in many cognitive, memory and learning skills. Researchers treated cells from the hippocampus directly with the serum samples and observed the impacts on cell generation and death, as well as on the levels of different cytokines.
Results showed that treatment with serum taken from COVID-19 patients with delirium increased cell death and decreased generation of new brain cells. Investigation of the serum showed that those patients with delirium had higher levels of the cytokine IL6, while there was no difference between patients on other cytokines. Treating the brain cells with the serum did produce higher levels of two other cytokines – IL12 and IL13 –suggesting there is a process or cascade where IL12 and I1L3 are generated by brain cells in response to inflammation in the body created by IL6, and together they produce the delirium.
