Thesis Characterising the Electrophysiological Properties of Cells in Health and Disease [on ME/CFS], 2024, Clarke

https://openresearch.surrey.ac.uk/e...siological-Properties-of-Cells/99893266002346


Doctoral Thesis
Characterising the Electrophysiological Properties of Cells in Health and Disease

Krista Samantha Pauline Clarke
University of Surrey
Doctor of Philosophy (PhD), University of Surrey
28/06/2024
DOI:
https://doi.org/10.15126/thesis.901143




Abstract
Dielectrophoresis Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome SARS-CoV-2 PBMC COVID-19 Chondrocyte Diagnosis

Biological cells possess intrinsic electrophysiological properties which are fundamental to cellular function. Changes in cell electrophysiology can act as a biomarker, for example to indicate transition from healthy to diseased cell states, changes in cell function, or cell differentiation. This thesis presents three studies which used dielectrophoresis (DEPtech 3DEP) and ζ-potential analysis (two fast, label-free, high-throughput, non-invasive, and low-cost tools) to examine the electrophysiological properties of two cell types, peripheral blood mononuclear cells (PBMCs) and chondrocytes, for novel medical applications.

The first study investigated the electrophysiological properties of PBMCs in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS); a debilitating disease of unknown pathophysiology with no reliable, validated, and quantitative diagnostic test. The dielectric and ζ-potential response of PBMCs to 1.5-hour hyperosmotic challenge differentiated ME/CFS donors from healthy controls with 81.80% sensitivity and 85.70% specificity. This shows potential as a quantitative diagnostic biomarker.

The second study examined whether the electrophysiological properties of PBMCs could act as a correlate of protection to SARS-CoV-2. Cytoplasmic conductivity in unchallenged PBMCs was significantly reduced in donors who had received three SARS-CoV-2 vaccine doses compared with unmatched COVID-19 naïve donors. Stimulation with the receptor binding domain of the SARS-CoV-2 spike protein resulted in significant differences in normalised values of membrane conductance in third-dose vaccinated donors, from COVID-19 naïve and second-dose donors.

The third study investigated chondrocytes, which are used extensively in cell-based cartilage-repair therapies. Chondrocytes rapidly dedifferentiate and become fibroblastic during monolayer cell culture – decreasing the success of reimplantation surgery. Significant changes in chondrocyte electrophysiological properties were observed over time in culture, laying the foundations for the identification of an electrophysiological biomarker that correlates with chondrocytic phenotype, to improve re-implantation outcome.

These studies demonstrate novel applications of dielectrophoresis and ζ-potential analysis – to quantitatively diagnose ME/CFS, identify changes in PBMCs following COVID-exposure, and changes in chondrocyte electrophysiology during dedifferentiation.



Files and links (1)

PDF
Krista Clarke Final Thesis 11.28 MB
PDF Embargoed Access, Embargo ends: 01/07/2025

 

Anyone been up to reading this?

Is study 1 relevant for understanding the OMF nano-needle results?

The three studies sound quite separate but does the author draw links between studies 1 (ME) and 3 (chondrocytes)? Because chondrocytes make extra-cellular matrix which has been discussed in a few threads lately as possibly relevant in ME

 

I think it's embargoed for a year.

 

Ah, missed that date 2025

Did a quick search to see if some of the papers included in the thesis have been published separately as sometimes seems to happen but the only published paper the thesis author appears to have been involved with to date is one on some extremely technical aspects of dielectrophoresis. So we'll have to wait

 

Tentatively answering my own question: it might be relevant. Krista is working on the MEA/MERUK funded project that's following up on Davis' findings, see this thread

 

> 81.80% sensitivity and 85.70% specificity

That's decent. Although not the stark difference Stanford found:



Although the thesis talks about a 1.5 hour hyperosmotic challenge and the chart above shows the separation is not as strong at 1.5hour as it is a bit later.

 

I just googled thesis embargos. They seem to imply something might be seeking publication or patenting. Which may be a hopeful sign.

 

Yes and – in fact, it’s not a very impressive results versus healthy controls. I hope it will be possible to refine this process. It was the scale of the separation in the nanoneedle results that was so striking.

 

Hopefully they will submit something for publication so we can read more details about how they recruited controls. Sometimes healthy controls are not so healthy as in the case of the NIH study where the healthy controls were relatives of patients and in many cases had orthostatic intolerance.

 

I don't think 81.80% sensitivity sounds bad. In my eyes it would probably be pretty close to what is achievable and considering the results of the intramural study and the problems of finding people with "true ME/CFS" is probably better than one can even expect. Anything much higher probably means you haven't identified a signal. I don't think specificity against controls from the general population matters too much either but you'd probably like to get some seperation from people with fatiguing illnesses and deconditioned people.

I think what will matter is whether there is a similar level of seperation as seen in the Stanford study where all controls looked similar but ME/CFS patients varied at different levels. In that case it might not matter if a few ME/CFS patients look similar to HCs, if the HCs all look somewhat similar. But if the results are all over the place and inconsistent things could be trickier.

More importantly will this tell us anything about pathology or might differences just be driven by being deconditioned, sample storage or something else? Has something like this been used to untangle pathology in a different illness?

 

https://meassociation.org.uk/2024/08/explaining-electrophysiological-properties-of-cells/