In a series of experiments, scientists at Beth Israel Deaconess Medical Center in Boston have found that gene profiles in the brains of patients with COVID-19 are similar to those observed in aging brains.
Using RNA sequencing to measure the levels of every gene expressed in tissue samples, the scientists assessed changes in gene expression profiles in the brains of COVID-19 patients and compared them to those changes observed in the brains of uninfected individuals.
The analysis, published this week in Nature Aging, suggested that many biological pathways that change with natural aging in the brain also changed in patients with severe COVID-19.
“Ours is the first study to show that COVID-19 is associated with the molecular signatures of brain aging,” co-first and co-corresponding author Maria Mavrikaki, an instructor of pathology at Beth Israel and Harvard Medical School, said in a statement. “We found striking similarities between the brains of patients with COVID-19 and aged individuals.”
Mavrikaki and colleagues analyzed a total of 54 postmortem human frontal cortex tissue samples from adults 22 to 85 years old. Of these, 21 samples were from severe COVID-19 patients and one from an asymptomatic COVID-19 patient who had died.
The samples were age- and sex-matched to uninfected controls with no history of neurological or psychiatric disease. The scientists also included an age- and sex-matched uninfected Alzheimer’s disease case for analysis as a control to a COVID-19 case which had comorbid Alzheimer’s disease, as well as an additional independent control group of uninfected individuals with a history of intensive care or ventilator treatment.
The group said it observed that gene expression in the brain tissue of patients who died of COVID-19 closely resembled that of uninfected individuals 71 years old or older.
While they did not find evidence that the SARS-CoV-2 virus was present in the brain tissue at the time of death, they discovered inflammatory patterns associated with COVID-19, suggesting that that the inflammation may contribute to the aging-like effects observed in the brains of patients with COVID-19 and long COVID, the researchers said.