Characterization and Biomarker Analyses of Post-COVID-19 Complications and Neurological Manifestations, 2021, Sun et al

The premise is really interesting. It seems that they can isolate particular extracellular vesicles using antibodies against a cell adhesion molecule that is expressed on neurons. I'm not quite sure if that means that the vesicles with the neuronal cell adhesion molecule have come from neuron cells, or are destined to be absorbed by neuron cells, or both.

And it seems that the EV cargo can differentiate a range of health conditions, and certain proteins are a marker for cognitive impairment in a range of conditions. I find it tremendously exciting that researchers with this type of background are turning their attention to post-Covid issues. And they seem to understand Long-covid - there isn't the idea that it's 'just fatigue'.

 

There wasn't much in the cytokine analysis, in terms of differentiating post-Covid participants with (nCov) and without (Cov) neurological symptoms.

I thought the IgG levels measured was interesting - these are in confirmed cases of Covid-19, with some of them having no or very low antibodies to Covid. People who had had Covid and have neurological symptoms (nCov) were more likely to have Covid antibodies than people who had had Covid and don't have neurological symptoms.

The researchers seem quite happy that the EVs they are labelling neuronal EVs (nEV) do indeed come from neurons, because they carry higher levels of synaptophysin.

Here are the levels of proteins associated with neural damage and inflammation that they looked for:


Levels do seem to be elevated in the people who have had Covid, compared to the controls. But the levels are, if anything, a bit higher in the people without post-Covid neurological symptoms (Cov) than those with them (nCov).

I mean, read this description for HMGB1:

You might think the people with headaches and and an inability to think well would have loads of the stuff. And they did have more than the controls, but, on average, less than the post-Covid people without lingering neurological symptoms.


It's a small study, with acknowledged problems, including 50% of the nCov having been hospitalised, while only 19% of the Cov group were.

But, investigation of these neuronal EV's might be a really good alternative to analysis of cerebrospinal fluid for ME/CFS and Long Covid research. I hope we see a bigger study from this group.