Neuronal LR11 expression does not differentiate between clinically-defined Alzheimer's disease and control brains

Area of Science:

• Neuroscience
• Neuropathology
• Genetics

Background:

• Alzheimer's disease (AD) is the primary cause of dementia in older adults.
• Early pathological changes in AD precede cognitive decline, making early event identification crucial for diagnosis and treatment.
• Previous research indicated reduced LR11 (SorLA) expression in AD and mild cognitive impairment (MCI) brains.

Purpose of the Study:

• To re-evaluate LR11 expression in a clinically diagnosed cohort to confirm or refute earlier findings.
• To investigate the association between LR11 expression levels and AD risk in a broader clinical context.

Main Methods:

• Quantitative immunohistochemistry was employed to measure LR11 protein levels.
• The study analyzed brain tissue from 43 participants from the Religious Orders Study with diagnoses of MCI, mild/moderate AD, or no cognitive impairment (NCI).
• Low LR11 expression was defined as being in the lowest tertile of expression across all cases.

Main Results:

• LR11 expression exhibited high variability across all diagnostic groups (MCI, AD, NCI) with no significant differences.
• Only 29% of AD cases displayed low LR11 expression, a proportion similar to that observed in MCI and NCI groups.
• No significant association was found between LR11 levels and AD-associated pathological markers.

Conclusions:

• The study challenges previous findings regarding a consistent reduction in LR11 expression in AD and MCI.
• The relationship between LR11 expression and Alzheimer's disease development appears more complex than previously hypothesized.
• LR11 expression variability suggests it may not be a universal early biomarker for AD across diverse clinical populations.