Proteins left behind by COVID-19 long after initial infection can cause cortisol levels in the brain to plummet, inflame the nervous system and prime its immune cells to hyper-react when another stressor arises, according to new animal research by University of Colorado Boulder scientists.
By News-Medical.net
Extracts
The study, published in the journal Brain Behaviour and Immunity, sheds new light on what might underly the neurological symptoms of Long COVID, an intractable syndrome which impacts as many as 35% of those infected with the virus.
Previous research has shown that SARS-CoV-2 antigens, immune-stimulating proteins shed by the virus that causes COVID-19, linger in the blood stream of Long COVID patients as much as a year after infection.
To explore just how such antigens impact the brain and nervous system, the research team injected an antigen called S1 (a subunit of the “spike” protein) into the spinal fluid of rats and compared them to a control group.
Matthew Frank, PhD, lead author, notes that cortisol is a critical anti-inflammatory, helps convert fuel into energy and is important for regulating blood pressure and the sleep-wake cycle and keeping the immune response to infection in check. One recent study showed that people with Long COVID tend to have low cortisol levels. So do people with chronic fatigue syndrome, research shows.
“We show for the first time that exposure to antigens left behind by this virus can actually change the immune response in the brain so that it overreacts to subsequent stressors or infection.”
He stresses that the study was in animals and that more research is necessary to determine whether and how low cortisol might lead to Long Covid symptoms in people.
MEA Comment
This is not the first research study to link lowered levels of cortisol (hypocortisolaemia) to Long Covid.
Hypocortisolaemia has also been reported in several research studies in ME/CFS – resulting in clinical trials to assess the use of low dose steroids (i.e. hydrocortisone) as a possible treatment.
Unfortunately, the results were not supportive and steroids should not therefore be used to treat ME/CFS.
Information on Low Dose Steroids & ME/CFS
Dr Charles Shepherd,
Trustee and Hon. Medical Adviser to the ME Association.
Member of the 2018-2021 NICE Guideline Committee.
Member of the 2002 Independent Working Group on ME/CFS.
More information
- BLOOMBERG: Striking Drop in Stress Hormone Predicts Long Covid in Study | August 12, 2022
- The American Journal of Medicine: Is Low Cortisol a Marker of Long Covid? | March 25, 2024