Soluble TREM2 is elevated in Parkinson's disease subgroups with increased CSF tau

Area of Science:

• Neuroscience
• Immunology
• Neuropathology

Background:

• Parkinson's disease (PD) is a common neurodegenerative disorder, second only to Alzheimer's disease.
• Cognitive impairment and dementia frequently develop in PD patients, significantly impacting morbidity.
• PD pathology involves alpha-synuclein aggregation, often co-occurring with amyloid-beta and tau, hallmarks of Alzheimer's disease.

Purpose of the Study:

• To investigate the role of soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in Parkinson's disease.
• To determine if cerebrospinal fluid (CSF) and/or plasma sTREM2 levels differ between Parkinson's disease subgroups defined by CSF biomarkers.
• To explore sTREM2 as a potential immune biomarker for neuronal injury in Parkinson's disease.

Main Methods:

• A cross-sectional study involving 165 participants: cognitively normal elderly, PD with no cognitive impairment, PD with mild cognitive impairment, and PD with dementia.
• Participants were stratified based on CSF amyloid-beta and tau levels.
• CSF and plasma sTREM2 concentrations were measured and analyzed across subgroups.

Main Results:

• CSF sTREM2 concentrations were significantly elevated in Parkinson's disease subgroups exhibiting a positive tau CSF biomarker signature.
• No significant elevation in CSF sTREM2 was observed in Parkinson's disease subgroups with a positive CSF amyloid-beta biomarker signature.
• These findings suggest a specific association between tau pathology and elevated sTREM2 in PD.

Conclusions:

• Elevated CSF sTREM2 in Parkinson's disease is linked to tau pathology, not amyloid-beta pathology.
• CSF sTREM2 may serve as a valuable surrogate immune biomarker for neuronal injury in Parkinson's disease.
• This research aids in understanding the immune response and neuropathological mechanisms in Parkinson's disease progression.