01 December 2011
Foulds, P. G., Mitchell, J. D., Parker, A., Turner, R., Green, G., Diggle, P., Hasegawa, M., Taylor, M., Mann,
D., Allsop, D
Parkinson's disease (PD) is characterized by the presence of Lewy bodies
containing phosphorylated and aggregated α-synuclein
(α-syn). α-Syn is present in human body fluids,
including blood plasma, and is a potential biomarker for PD.
Immunoassays
for total and oligomeric forms of both normal and
phosphorylated (at Ser-129) α-syn have been used to assay plasma samples
from a longitudinal cohort of 32 patients with PD
(sampled at mo 0, 1, 2, 3), as well as single plasma samples from a
group
of 30 healthy control participants.
The levels of
α-syn in plasma varied greatly between individuals, but were remarkably
consistent over time within the same individual
with PD. The mean level of phospho-α-syn was found to be higher (P=0.053) in the PD samples than the controls, whereas this was not the case for total α-syn (P=0.244), oligo-α-syn (P=0.221), or oligo-phospho-α-syn (P=0.181).
Immunoblots of plasma revealed bands (at 21, 24, and 50–60 kDa)
corresponding to phosphorylated α-syn.
Thus, phosphorylated
α-syn can be detected in blood plasma and shows
more promise as a diagnostic marker than the nonphosphorylated protein.
Longitudinal
studies undertaken over a more extended time period
will be required to determine whether α-syn can act as a marker of
disease
progression.
