An ultrastructural study of Pick bodies

Area of Science:

• Neuroscience
• Cell Biology
• Pathology

Background:

• Pick bodies (PB) are abnormal protein aggregates found in certain neurodegenerative diseases.
• Understanding the ultrastructure of PB is crucial for differentiating them from other tauopathies like Alzheimer's disease.

Purpose of the Study:

• To conduct an ultrastructural analysis of filamentous components within Pick bodies.
• To compare the morphology and composition of filaments in Pick bodies with those in Alzheimer-type neurofibrillary tangles.

Main Methods:

• Transmission electron microscopy was used for ultrastructural examination.
• Filament dimensions were quantified using histograms.
• Morphological classification of filamentous structures was performed.

Main Results:

• Pick bodies contain a heterogeneous mix of filaments, unlike the uniform paired helical filaments (PHF) in Alzheimer's disease.
• Three distinct filament types were identified: altered neurofilaments (10-14 nm), unique tubules (15-22 nm), and PHF.
• PHF in Pick bodies exhibit different crossover distances compared to Alzheimer's PHF, resembling those in progressive supranuclear palsy.

Conclusions:

• Pick bodies are composed of diverse filamentous structures, distinct from the characteristic PHF of Alzheimer's disease.
• The observed filament heterogeneity suggests a complex pathological process in Pick's disease.
• Ultrastructural differences in PHF may aid in differential diagnosis of tauopathies.