Megakaryocytes in cerebral vessels may cause neurological impairment in COVID-19

Megakaryocytes in cortical capillaries of patients with coronavirus disease (COVID) -19 can cause marked ischemic changes and lead to various neurological manifestations, according to study results published as a research letter in JAMA Neurology.

Many patients with COVID-19 may experience neurological impairment during the acute illness and after recovery from the acute infection. These manifestations can include confusion, altered state of consciousness, and brain fog. The aim of this study was to evaluate histopathological changes that may underlie these neurological disorders.

Researchers examined brain tissue from autopsies of patients with COVID-19 at Johns Hopkins University and Mass General Brigham to identify histopathological changes in this population. In addition, they included 2 patients without COVID-19 with hypoxic-ischemic changes.

The results showed that megakaryocytes were present in cortical capillaries in 5 patients with COVID-19. These cells were not seen in the cortex of either COVID-19 negative case with hypoxic brain changes.

Several studies have previously shown that endothelial dysfunction can play an important role in severe COVID-19 illness. Research found megakaryocytes are present in several other organs, including the lungs, in patients with COVID-19. However, this is the first report of megakaryocytes in cerebral vessels.

The study’s researchers suggested that in patients with COVID-19, megakaryocytes are recruited into the circulation and pass through the lungs. In the current study, they observed these megakaryocytes in cortical capillaries in 33% of the cases examined.

“We report here a finding that, in some cases, may help identify it by analyzing the brain tissue of patients who have died of COVID-19,” the study researchers wrote. They added, “By blocking the flow through individual capillaries, these large cells become [megakaryocytes] could cause an ischemic change in a particular pattern, potentially leading to an atypical form of neurological impairment. ”


Nauen DW, Hooper JE, Stewart CM, Solomon IH. Assessment of the brain capillaries in coronavirus diseases 2019. JAMA Neurol. Published online February 12, 2021. doi: 10.1001 / jamaneurol.2021.0225

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