1. Etiopathogenesis of Alzheimer's disease

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.

4. To understand Alzheimer’s disease, it’s important to know a bit about the brain…

5. Cells of the nervous system
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.

7. Structure of the neuron

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

11. CERBRAL HEMCCCCCCCERISPHERES

13. THE BRAIN STEM

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)

16. Etiology for AD
Unknown
Aging
Familial cause

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.

19. Contd….
Enzymes cut the APP into fragments of protein, including beta-amyloid.

20. Contd…
Beta-amyloid fragments come together in clumps to form plaques.

21. Contd..
In AD, many of these clumps form, disrupting the work of neurons. This affects the hippocampus and other areas of the cerebral cortex.

22. NORMAL AND AD CEREBRAL CORTEX

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.

24. NEURO FIBRILLARY 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.