2. Introduction
• Alzheimer’s is the most common cause of
dementia in adult life and is associated with
the selective damage of brain regions and
neural circuits critical for memory and
cognition.
• The pathogenesis of this disease is complex,
and involves many molecular, cellular, and
physiological pathologies.
3. What is AD?
• Alzheimer’s disease (AD) is a devastating
illness characterized by progressive memory
loss, impaired thinking, personality change,
and inability to perform routine tasks of daily
living.
5. Cells of the nervous system
1. Neurons
2.Neuroglia cells
Astrocyte
Oligodentrocytes
Ependymal cells
Microglia
6. Neurons
• The brain has billions of neurons, each with an
axon and many dendrites.
• To stay healthy, neurons must communicate
with each other, carry out metabolism, and
repair themselves.
• AD disrupts all three of these essential jobs.
9. Etiology and risk factors
• Although the risk of developing AD increases
with age – in most people with AD, symptoms
first appear after age 60 – AD is not a part of
normal aging. It is caused by a fatal disease
that affects the brain.
• Family history
15. Other crucial parts….
• Hippocampus: where short-term memories
are converted to long-term memories
• Thalamus: receives sensory and limbic
information and sends to cerebral cortex
• Hypothalamus: monitors certain activities and
controls body’s internal clock
• Limbic system: controls emotions and
instinctive behavior (includes the
hippocampus and parts of the cortex)
17. AD and brain
• Amyloid plaques
• Neuro fibrillary tangles
• Loss of connection between cells and cell
death
• Genetic factor
• Cellular and other cause
18. Amyloid plaque
Amyloid precursor protein (APP) is the
precursor to amyloid plaque.
APP sticks through the neuron membrane.
23. Neurofibrillary tangles
• Neurons have an internal support structure
partly made up of microtubules. A protein
called tau helps stabilize microtubules.
• In AD, tau changes, causing microtubules to
twist together in helical fashion , and tau
proteins clump together to form
neurofibrillary tangles.
26. Genetic factor
• Presenillin -1 and 2 genes are muted to cause
over production of betaamyloid(cell
damage/death/inflammation)
• Apolipoprotein E (ApoE) gene on chromosome
19
• Four allele of apolipoprotein –E that is Apo E-
2,3,4.
• Role in cholesterol transport
• E4 associated with AD but E2 is protective
27. Contd....
– ApoE4 promotes the formation of neuritic
plaques;also binds to beta-amyloid to make it
insoluble.
-Apo E-4 increase the risk of person to develop
late onset of AD
– E4 neither necessary nor sufficient to cause AD
(many people have apoE4 gene, but do not
have AD).
28. Cellular and others ….
• Aging causes formation of free radicals
• HT, obesity, smoking, atherosclerosis, high
cholesterol and homocysteine increase the
risk of AD.
29. Conclusion
The neural damage in AD is irreversible, and
hence the disease cannot be cured.
There is no effective drug for relieving
symptoms, and no prospect of one in the near
future.