Based on the similar symptoms of the post-COVID syndrome (long-term COVID) and chronic fatigue syndrome, American researchers studied the biological basis of these two conditions and found a lot in common. The article is published in the journal Proceedings of the National Academy of Sciences.
Myalgic encephalomyelitis, or chronic fatigue syndrome, is a complex disease of the central nervous system, which affects from one to two and a half million people in the United States alone. It is characterized by such symptoms as severe, debilitating fatigue that does not pass even after a long rest, sleep disorders, difficult thinking, usually called “brain fog,” anomalies of the autonomic nervous system. As a rule, all these symptoms worsen after physical or cognitive stress.
In almost the same way, patients with post-COVID syndrome describe their condition, who, after suffering from COVID-19, fatigue, shortness of breath, problems with sleep, memory, and concentration persist for several weeks or even months.
Researchers from the Johns Hopkins University School of Medicine have suggested that both syndromes have a common cause — a biological reaction of the body to stress associated with infections or other external influences.
“The response to infections or injuries is complex and covers all systems of the body. With any failure, it can cause a feeling of fatigue, brain fog, pain, and other symptoms,” the words of the lead author of the study, Bindu Paul, associate professor of the Department of Pharmacology and Molecular Sciences of the Faculty of Medicine, are quoted in a press release from Johns Hopkins University.
Both with the syndrome of increased fatigue and with prolonged COVID, the authors note the central role of oxygen molecules that accumulate in cells. This process, called oxidative stress, leads to the occurrence at the cellular level of a redox imbalance associated with inflammation and metabolic disorders that are observed in both diseases.
The authors studied the relationship between the redox imbalance and other reactions of the body to stress — inflammation, energy metabolic deficiency, and hypo metabolic state — and the manifestations of chronic fatigue and long-term COVID syndromes. Previously, Paul and his colleagues recorded oxidative stress in diseases such as Huntington’s disease, Alzheimer’s disease, and Parkinson’s disease.
“We don’t know yet how many patients with COVID-19 will have long-term symptoms, but it is estimated that at least seven percent of them will,” says another study participant Anthony Komaroff from Harvard Medical School in Boston.
In the future, scientists hope to continue studying the molecular mechanisms of diseases characterized by oxidative stress, inflammation, and metabolic disorders.