Thread by @MBVanElzakker

New preprint of a #longCOVID study from us:

"Neuroinflammation in post-acute sequelae of COVID-19 (PASC) as assessed by [11C]PBR28 PET correlates with vascular disease measures"biorxiv.org/content/10.110…

We conducted PET neuroimaging on 12 long COVID patients with diverse symptoms, and compared to 43 healthy controls that had already been scanned in the same scanner under the same protocol (most pre-pandemic). The PET radioligand that we used detects the TSPO protein, and...

...increased TSPO signal is consistent with neuroinflammation processes like glial activation, penetrating immune cells, or inflammatory activation of neurovascular endothelial cells. This is the whole-brain pattern of significantly increased PET signal in the cases vs. controls:

The bar graph shows the average whole-brain PET signal from each participant; we extract and plot those data to make sure the overall effect is not driven by outliers. We didn't really think there is a "long COVID brain region" per se so we also extracted PET data from specific..

...structures, also to look at their distribution (data here are normalized to control means). You can see a wide distribution among controls, but long COVID participants were consistently higher.
pMCC=posterior midcingulate cortex
CC=corpus callosum
ACC=anterior cingulate cortex

Some (not all) of the PET signal pattern seemed to be consistent with areas where there are windows in the blood-brain barrier, so we wanted to investigate if blood-borne factors might be related to that PET signal. We collected blood samples from 11 long COVID participants...

...right before their scan (not controls, which were from several different mostly pre-pandemic studies). Based on existing studies we tested for markers related to vascular health and found pretty strong correlations between PET signal and 7 different vascular-related factors.

In the long COVID group, we found moderate-to-strong correlations between the neuroinflammation-related PET signal and: Fibrinogen, α2-macroglobulin, orosomucoid, fetuin A, sL-selectin, pentraxin-2, and haptoglobin (some of these have alternate names).

Special thanks to the study participants for generously working with us (and in many cases returning for multiple studies) and thanks to PolyBio Research Foundation @PolyBioRF donors for funding this project!