Publication date: Oct 10, 2024

After acute COVID-19, five percent of people experience persistent depressive symptoms and reduced cognitive function (COVID-DC). Theoretical models propose that astrogliosis is important in long COVID but measures primarily indicative of astrogliosis have not been studied in the brain of long COVID or COVID-DC. The objective is to measure [C]SL25. 1188 total distribution volume ([C]SL25. 1188 V), index of monoamine oxidase B (MAO-B) density and marker of astrogliosis with PET in COVID-DC and compare to healthy controls. In 21 COVID-DC cases and 21 healthy controls, [C]SL25. 1188 V was measured in prefrontal cortex, anterior cingulate cortex, hippocampus, dorsal putamen, and ventral striatum. Depressive symptoms were measured with the Beck Depression Inventory-II and cognitive symptoms were measured with neuropsychological tests. [C]SL25. 1188 V was higher in COVID-DC in prefrontal cortex, anterior cingulate cortex, hippocampus, dorsal putamen, and ventral striatum compared to healthy controls. Depressive symptom severity correlated negatively with [C]SL25. 1188 V across prioritized brain regions. More recent acute COVID-19 correlated positively with [C]SL25. 1188 V, reflecting higher values since predominance of the omicron variant. Exploratory analyses found greater [C]SL25. 1188 V in hippocampus, dorsal putamen, and ventral striatum compared to major depressive episode controls with no history of COVID-19; and no relationship to cognitive testing in prioritized regions. Results strongly support the presence of MAO-B labelled astrogliosis in COVID-DC throughout the regions assessed although the association of greater astrogliosis with less symptoms raises the possibility of a protective role. Magnitude of astrogliosis in COVID-DC is greater since emergence of omicron variant.

Semantics

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