Patients with COVID-19 typically report headaches, confusion and other neurological symptoms, but doctors don’t fully understand how the disease targets the brain during infection.
Now researchers from Tulane University have shown in detail how COVID-19 affects the central nervous system, according to a new study published in Communication Nature.
The results are the first comprehensive assessment of the neuropathology associated with SARS-CoV-2 infection in a non-human primate model.
The team of researchers found severe brain inflammation and damage consistent with reduced blood flow or oxygen to the brain, including neuron damage and death. They also found small bleeds in the brain.
Surprisingly, these findings were present in subjects who did not suffer severe respiratory illness from the virus.
Tracy Fischer, Ph.D., principal investigator and associate professor of microbiology and immunology at Tulane National Primate Research Center, has studied the brain for decades. Shortly after the primate center launched its COVID-19 pilot program in the spring of 2020, it began studying brain tissue from several subjects who had been infected.
Fischer’s initial findings documenting the extent of brain damage from SARS-CoV-2 infection were so striking that she spent the following year further refining the study’s controls for ensure that the results were clearly attributable to the infection.
“Because the subjects did not experience significant respiratory symptoms, no one expected them to have the severity of disease that we found in the brain,” Fischer said. “But the results were distinct and profound, and unmistakably the result of infection. »
The findings are also consistent with autopsy studies of people who have died from COVID-19, suggesting that nonhuman primates may serve as a suitable model, or proxy, for how humans experience the disease.
Neurological complications are often among the first symptoms of SARS-CoV-2 infection and can be the most severe and long-lasting. They also affect people indiscriminately – of all ages, with or without comorbidities, and with varying degrees of disease severity.
Fischer hopes that this study and future studies that investigate how SARS-CoV-2 affects the brain will contribute to the understanding and treatment of patients suffering from the neurological consequences of COVID-19 and long COVID.