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There is a critical need for good biomarkers in neurodegenerative research.
A biomarker is an objective indicator of a medical state that can be assessed from outside a patient, and can be measured accurately and reproducibly. It could come in the form of a medical imaging application or a biological sample (such as a blood test).
Recent research points towards a particular protein (referred to as GPNMB) that could be a potential biomarker for a specific subtype of Parkinson’s.
In today’s post, we will review some of the research on this topic and consider how a biomarker could potentially be used in Parkinson’s research.
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Back in 2016, some researchers reported something interesting.
They had been investigating cells collected from people with a condition called Gaucher disease (Pronounced: ‘Go-Shay’; don’t ask – we’ll discuss what it is in a moment, just let me get the intro out of the way). Specifically, the scientists were seeking potential biomarkers for Gaucher disease… and they might have found one.
Here is their report:
Title: Elevation of glycoprotein nonmetastatic melanoma protein B in type 1 Gaucher disease patients and mouse models.
Authors: Kramer G, Wegdam W, Donker-Koopman W, Ottenhoff R, Gaspar P, Verhoek M, Nelson J, Gabriel T, Kallemeijn W, Boot RG, Laman JD, Vissers JP, Cox T, Pavlova E, Moran MT, Aerts JM, van Eijk M.
Journal: FEBS Open Bio. 2016 Jul 30;6(9):902-13.
PMID: 27642553 (This report is OPEN ACCESS if you would like to read it)
In the study, the researchers collected cells from the spleen of an individual with Gaucher disease and looked for proteins in the cells that were higher than normal.
They found glycoprotein non-metastatic melanoma protein B (GPNMB, also known as osteoactivin) was ridiculously high. Off the charts high. They then compared GPNMB levels in blood samples collected from 59 people with Gaucher disease and 20 healthy controls. As you can see in the graph below, GPNMB levels were on average 25‐fold higher in all of the 59 people with Gaucher disease (Note: the Y axis is logarithmic):
Interestingly, when the individuals with Gaucher disease started the standard treatment for the condition, the levels of GPNMB collectively dropped:
And this result has been independently validated (Click here to read that report). The second study used a larger cohort of individuals with Gaucher disease (155 patients) and they found a >15-fold elevation of GPNMB in the blood of this group (compared to controls). And again these high levels were reduced when the Gaucher group started treatment:
A third study found that GPNMB levels in the brains of a mouse model of Gaucher disease correlated with disease severity in the mice, and also reported elevated GPNMB levels in brain samples from patients with Gaucher disease.
All of the research groups concluded that their data supports the potential utility of GPNMB as a biomarker of Gaucher disease.
Great! But what is Gaucher disease and why is this on a website for Parkinson’s research?