Neuroinflammation After COVID-19 With Persistent Depressive and Cognitive Symptoms 2023 Braga et al

Key Points

Question Is translocator protein distribution volume (TSPO VT), an index of gliosis (an inflammatory change), measured by positron emission tomography, elevated in the brain after acute COVID-19 infection with sequelae of depressive and cognitive symptoms?

Findings In this case-control study, TSPO VT was elevated in 20 participants with persistent depressive and cognitive symptoms after initially mild to moderate COVID-19 infection when compared with 20 healthy controls, more prominently in the ventral striatum and dorsal putamen. The TSPO VT in the dorsal putamen of COVID-19 cases negatively correlated with motor speed.

Meaning These findings suggest that gliosis, especially in the ventral striatum and dorsal putamen, may reflect injury, ongoing inflammation, or both and provide directions for further therapeutic development.

Abstract
Importance Persistent depressive symptoms, often accompanied by cognitive symptoms, commonly occur after COVID-19 illness (hereinafter termed COVID-DC, DC for depressive and/or cognitive symptoms). In patients with COVID-DC, gliosis, an inflammatory change, was suspected, but measurements of gliosis had not been studied in the brain for this condition.

Objective To determine whether translocator protein total distribution volume (TSPO VT), a marker of gliosis that is quantifiable with positron emission tomography (PET), is elevated in the dorsal putamen, ventral striatum, prefrontal cortex, anterior cingulate cortex, and hippocampus of persons with COVID-DC.

Design, Setting, and Participants This case-control study conducted at a tertiary care psychiatric hospital in Canada from April 1, 2021, to June 30, 2022, compared TSPO VT of specific brain regions in 20 participants with COVID-DC with that in 20 healthy controls. The TSPO VT was measured with fluorine F 18–labeled N-(2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide ([18F]FEPPA) PET.

Main Outcomes and Measures The TSPO VT was measured in the dorsal putamen, ventral striatum, prefrontal cortex, anterior cingulate cortex, and hippocampus. Symptoms were measured with neuropsychological and psychological tests, prioritizing outcomes related to striatal function.

Results The study population included 40 participants (mean [SD] age, 32.9 [12.3] years). The TSPO VT across the regions of interest was greater in persons with COVID-DC (mean [SD] age, 32.7 [11.4] years; 12 [60%] women) compared with healthy control participants (mean [SD] age, 33.3 [13.9] years; 11 [55%] women): mean (SD) difference, 1.51 (4.47); 95% CI, 0.04-2.98; 1.51 divided by 9.20 (17%). The difference was most prominent in the ventral striatum (mean [SD] difference, 1.97 [4.88]; 95% CI, 0.36-3.58; 1.97 divided by 8.87 [22%]) and dorsal putamen (mean difference, 1.70 [4.25]; 95% CI, 0.34-3.06; 1.70 divided by 8.37 [20%]). Motor speed on the finger-tapping test negatively correlated with dorsal putamen TSPO VT (r, −0.53; 95% CI, −0.79 to −0.09), and the 10 persons with the slowest speed among those with COVID-DC had higher dorsal putamen TSPO VT than healthy persons by 2.3 (2.30 divided by 8.37 [27%]; SD, 2.46; 95% CI, 0.92-3.68).

Conclusions and Relevance In this case-control study, TSPO VT was higher in patients with COVID-DC. Greater TSPO VT is evidence for an inflammatory change of elevated gliosis in the brain of an individual with COVID-DC. Gliosis may be consequent to inflammation, injury, or both, particularly in the ventral striatum and dorsal putamen, which may explain some persistent depressive and cognitive symptoms, including slowed motor speed, low motivation or energy, and anhedonia, after initially mild to moderate COVID-19 illness.

https://jamanetwork.com/journals/ja...ign=ftm_links&utm_content=tfl&utm_term=053123

 

https://www.camh.ca/en/camh-news-an...brain-inflammation-associated-with-long-covid

 

I always think about these type of studies, that it would be great if the researchers turned their interest to investigating pwME, using the same tools.

It often seems so close, and yet so far away.

 

Me too. If we find it in LC, we should attempt to replicate it in ME. This work reminds me strongly of Jared Younger's work (S4ME tag) on neuroinflammation. Personally, I believe it's a reasonable guess that low-grade neuroinflammation is a cause of ME.

 

Yes, I think it's a reasonable guess. The Canadian ME/CFS Overview, page 18, notes edema or demyelination as findings on brain MRIs of pwME. I will put the link up in a bit.

ETA:

The link to the CCC ME/CFS Overview; on page 18, about 2/3 of the way down; see "MRI brain scans".

https://www.mefmaction.com/images/stories/Overviews/ME-Overview.pdf.

And ETA #2: spelling corrected