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The ageing brain

The ageing brain. Volume reduction: begins around 50 with a loss of brain weight of around 2-3% per decade Changes in nerve cell numbers and size - various studies with various results ( 10-25%), although some structures seem resistent

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The ageing brain

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  1. The ageing brain • Volume reduction: begins around 50 with a loss of brain weight of around 2-3% per decade • Changes in nerve cell numbers and size - various studies with various results ( 10-25%), although some structures seem resistent - dendritic and synaptic changes may be compensated by sprouting

  2. Microscopy of the aging brain • Increase in lipofuscin • Senile plaques • Neurofibrillary tangles • Granulovacuolar degeneration • Hirano bodies • Leukoaraiosis • Amyloid (congophilic) angiopathy

  3. Neurodegenerations • Damage to lysosomes, nuclear DNA, mitochondria leads to release of caspases, initiating apoptosis. • In many if not most neurodegenerations this damage is started by abnormal protein-protein interactions leading to protein storage. • Examples: • Ubiquinopathies • Tauopathies • Synucleinopathies • Prion diseases

  4. Ubiquinopathies: Alzheimer’s disease Pre-senile and senile forms Onset before or after 65 years of age Progression slow (often > 1 decade) Pathological changes are similar to aging, but more severe

  5. Senile plaque Heterogeneous structure Amyloid core surrounded by a clear zone Crown of filamentous or granular material made up of neuronal projections filled with argyrophilic filaments and debris Macrophages and astrocytes

  6. Tauopathies • Pick’s disease • Progressive Supranuclear Palsy • Cortico basal degeneration • etc

  7. Pick’s disease • Dementia with relative rapid progression with frontal symptoms (aggressive behavior often, or problems with initiation of tasks), onset from 50 years of age, frequently hereditary. • Gross findings are characterized by a lobar atrophy affecting the frontal lobe and the anterior temporal lobe (mostly the anterior 1/3 of the superior temporal gyrus) • Histology:Pick’s cells (swollen neurons ), Pick’s bodies ( argyrophilic intracytoplasmic inclusions), neuronal loss and gliosis

  8. Progressive supranuclear palsy • Dementia combined with vertical gaze paralysis, and Parkinsonism • Abnormal tau accumulation in neurons and glial cells, neuronal loss and gliosis • Characteristic topography:In the midbrain and striatum (Substantia nigra, red nucleus, colliculi, globus pallidus, subthalamic nucleus, periaqueductal grey matter, dorsal and medial raphe, locus coeruleus)

  9. Synucleinopathies • Parkinson’s disease • Dementia with Lewy bodies • etc

  10. M. Parkinson • Onset 30-80 • Rest tremor mostly starting with hands (like counting money) • Stooped posture, walking with small steps • Depigmentation of Substantia nigra and Locus coeruleus • Lewy bodies and loss of pigmented neurons • Loss of dopaminergic innervation to the striatum

  11. Parkinson’s disease

  12. Lewy bodies

  13. Synuclein

  14. Dementia with Lewy bodies

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