April 13, 2023 – In case you or somebody you realize is experiencing “mind fog” after COVID-19, scientists now have a potential clarification — and it won’t deliver a lot consolation.
Researchers in Germany discovered that a part of the virus, the spike protein, stays within the mind lengthy after the virus clears out.
These investigators found the spike protein from the virus in mind tissue of animals and folks after loss of life. The discovering suggests these virus fragments construct up, stick round, and set off irritation that causes lengthy COVID signs.
About 15% of COVID sufferers proceed to have long-term results of the an infection regardless of their restoration, stated senior examine writer Ali Ertürk, PhD, director of the Institute for Tissue Engineering and Regenerative Drugs on the Helmholtz Middle Munich in Germany.
Reported neurological issues embody mind fog, mind tissue loss, a decline in considering skills, and issues with reminiscence, he stated.
“These signs clearly recommend damages and long-term adjustments brought on by SARS-CoV-2 within the mind, the precise molecular mechanisms of that are nonetheless poorly understood,” Ertürk stated.
The researchers additionally suggest a approach the spike protein can get into the mind of their preprint report revealed on-line earlier than peer assessment April 5 on bioRxiv.
Delivered by circulating blood, the spike protein can keep inside small openings within the bone marrow of the cranium referred to as niches. It could possibly additionally reside in the meninges, skinny layers of cells that act as a buffer between the cranium and the mind. From there, one principle goes, the spike protein makes use of channels to enter the mind itself.
The hope is researchers can develop remedies that block a number of steps on this course of and assist individuals keep away from lengthy COVID mind points.
“This can be a very regarding report that actually demonstrates the SARS-CoV-2 spike protein within the skull-meninges-brain axis in postmortem people,” stated Eric Topol, MD, director of the Scripps Analysis Translational Institute in La Jolla, CA, and editor-in-chief of Medscape, WebMD’s sister web site for medical professionals.
Having the spike protein accumulate in buildings proper outdoors the mind and inflicting ongoing irritation is sensible to Topol. The clustering of spike proteins would set off an immune response from this area of interest reservoir of immune cells that trigger the irritation related to lengthy COVID and the signs similar to mind fog, he stated.
Issues with considering and reminiscence after COVID an infection are comparatively frequent. One analysis workforce discovered 22% of individuals with lengthy COVID particularly reported this difficulty, on common, throughout 43 revealed research. Even individuals who had gentle COVID sickness can develop mind fog later, Ertürk and colleagues notice.
So why are researchers blaming the spike protein and never the entire COVID virus? As a part of the examine, they discovered SARS-CoV-2 virus RNA in some individuals after loss of life and never in others, suggesting the virus doesn’t have to be there to set off mind fog. In addition they injected the spike protein straight into the brains of mice and confirmed it may well trigger cells to die.
Researchers additionally discovered no SARS-CoV-2 virus within the mind parenchyma, the useful tissue within the mind containing nerve cells and non-nerve (referred to as glial) cells, however they did detect the spike protein there.
Investigators had been stunned to seek out spike protein within the cranium niches of people that survived COVID and died later from one other trigger. Ertürk, lead writer and PhD scholar Zhouyi Rong, and their colleagues discovered spike protein in 10 of 34 skulls from individuals who died from non-COVID causes in 2021 and 2022.
In addition they discovered COVID can change how proteins act in and across the mind. A few of these proteins are linked to Parkinson’s illness and Alzheimer’s illness, however have by no means earlier than been linked to the virus.
One other surprising discovering was how shut the findings had been in mice and people. There was a “exceptional similarity of distribution of the viral spike protein and dysregulated proteins recognized within the mouse and human samples,” Ertürk stated.
Exams for protein adjustments within the cranium or meninges can be invasive however potential in comparison with sampling the parenchyma contained in the mind. Even much less invasive can be testing blood samples for altered proteins that would determine individuals most vulnerable to growing mind issues after COVID sickness.
It would take extra mind science to get there. “Designing therapy methods for these neurological signs requires an in-depth information of molecules dysregulated by the virus within the mind tissues,” Ertürk stated.