Alcohol consumers with liver pathology rarely display α-synuclein pathology

Area of Science:

• Neuropathology
• Toxicology
• Gerontology

Background:

• Alcohol consumption's potential neuroprotective effects, particularly against Parkinson's disease (PD), remain an area of interest.
• Understanding the relationship between liver pathologies (LP) induced by alcohol and neurodegenerative markers is crucial for elucidating disease mechanisms.

Purpose of the Study:

• To investigate the association between alcohol-related liver pathologies and key neuropathological hallmarks of neurodegenerative diseases, including alpha-synuclein (αS).
• To explore the correlation between liver steatosis, fibrosis, inflammation, and the presence of αS, hyperphosphorylated tau (HPτ), amyloid-beta (Aβ), and TDP-43 in postmortem brain tissue.

Main Methods:

• Postmortem brain and liver tissue samples from 100 subjects (aged 51-93) were analyzed using standardized assessment strategies.
• Subjects were categorized based on the severity of alcohol-induced liver pathologies (none, mild, moderate, severe).
• Correlations between liver pathology markers and brain protein aggregates (αS, HPτ, Aβ, TDP-43) and astrocyte types were statistically evaluated.

Main Results:

• A significant negative correlation was observed between liver steatosis/fibrosis and brain αS pathology.
• Severe liver pathologies were associated with a higher frequency of Alzheimer's type II astrocytes.
• Dementia was more prevalent in subjects with mild LP compared to those with severe LP, often attributed to mixed pathologies.

Conclusions:

• Findings support the hypothesis that alcohol consumption may be protective against α-synucleinopathies, a key feature of Parkinson's disease.
• Alcohol-induced liver damage shows a complex interplay with brain pathology, but appears to reduce αS accumulation.
• Further research is warranted to fully understand the mechanisms underlying alcohol's potential neuroprotective role in synucleinopathies.