Tissue samples
Histological examination of phosphorylated a-syn in different peripheral
tissue biopsies of PD cases has been subject of increasing interest
[12, 14]. Detection of phosphorylated a-syn aggregates in
the autonomic nerve fibers of salivary glands and skin shown promise as
an early histological biomarker [35, 36]. However, the finding is
not specific for PD as similar deposits can be observed in other
alpha-synucleinopathies, too [35]. Similarly, gastrointestinal
biopsy could represent an accessible strategy to assess a-syn
neuropathology in PD patients [37].
Peripheral tissue miRNAs may be of significance as hsa-miR-1260a from PD
patients nasal and buccal swabs was significantly increased as compared
with healthy controls [38]. Interestingly, non-coding miRNAs,
miR-134 and miR-141 downregulated CDNF levels in an experimental setting
calling for clinical studies on the biomarker properties of these miRNAs
[34].