Dementia Flashcards

1
Q

What is the most common type of dementia?

Alzheimers Disease
Vascular Dementia
Mixed AD + VaD
Dementia with Lewy Body

A

What is the most common type of dementia?

Alzheimers Disease
Vascular Dementia
Mixed AD + VaD
Dementia with Lewy Body

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2
Q

Name 4 non-modifiable risk factors for dementia [4]

Name 4 modifiable risk factors for dementia [4]

A

Non-modifiable risk factors
* Age (greatest risk factor)
* Genetic predisposition
* Family history
* Downs syndrome

Modifiable risk factors
* Vascular Risk factors (high cholesterol, hypertension, diabetes)
* Cognitive inactivity (low education attainment)
* Environment (head injury)
* Depression

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3
Q

Pathogenesis of Alzeimers DIsease (AD)

State the name of this protein [1]

Where is it found within the cell? [1]

A

Amyloid plaque - found in cytosol

Early disease progession

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4
Q

Pathogenesis of Alzeimers DIsease (AD)

State the name of this protein [1]

Where is it found within the cell? [1]

Is it associated with early or late disease progression? [1]

A

Tau intraneuronal

Later disease progression

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5
Q

Pathogenesis of Alzeimers DIsease (AD)

Name the genes [3] and proteins [3] that are critical for early onset AD [3]

A

Genes for early onset AD (not common). caused by the following genes
* Amyloid precursor protein (APP)
* Presenellin 1 (PSEN1)
* Presenellin (PSEN2)

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6
Q

Pathogenesis of Alzeimers DIsease (AD)

What is the final product of amyloid precursor protein being cleaved? [1]

A

Aβ peptides (this is a normal metablic event)

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7
Q

Which gene is associated with late onset AD? [1]

A

Late onset (60+ years of age)
* Apolipoprotein E (Ch.19)

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8
Q

Presenilin 1 & 2 are responsible for making which secretase? [1]

A

Presenilin 1 & 2 proteins is one part (subunit) of a complex called gamma- (γ-) secretase.

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9
Q

Describe the difference in APP processing between the amyloidogenic and non-amyloidogenic pathway

A

APP protein has 3 cleaving sites. Depending on combination of secretases have will cause different payhways

Non-amyloidogenic pathway:
* alpha-secretases and gamma-secretases

Amyloidogenic pathway:
* Beta-secretases and gamma-secretases
* Generates: AB peptide with two isoforms:AB 40 and AB 42.

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10
Q

Label A-D

A

A: gamma secretase
B: alpha secretase
C: Beta secretase
D: gamma secretase

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11
Q

Name the two isoforms of AB protein that form insoluble plaques

A

AB 40 and AB 42

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12
Q

Describe the inflammatory response caused by familial forms of AD pathogenesis (from early AD genes) [2]

Describe the effect of amyloid plaques within neurons (caused by familial forms of AD pathogenesis) [2]

A

Inflammatory response:
* Microglial activation - inability to clear AP causes chronic inflammation of microglia
* Astrocytosis (increase in amount) and acute phase protein release

Progressive neuritic injury within amyloid plaques
* Disruption of neuronal metabolism and ionic homeostasis:
* Oxidative Stress

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13
Q

Which molecule is APOE involved in the metabolism of? [1]

What are the three isoforms of APOE? [3]
Which is the greatest risk for AD and why? [2]

A

Involved in cholesterol metabolism

APOE2; APOE3 & APOE4

APOE4 has greatest risk factor and decreases clearance of extracellular Aβ.

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14
Q

Which posttranslational modification does the microtubule-binding protein, tau undergo which contributes to Alzheimer’s pathology? [1]

Which amino acids can undergo this specific post translational modification? [3]

A

Hyperphosphorylation.

Tyrosine, serine and threonine.

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15
Q

Which change in AD pathophysiology relates to cognitive decline? [1]

A

Hyperphosphorylated tau tangles correlate to cognitive decline (Amyloid plaques does not)

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16
Q

Normal function of tau? [1]

What is abnormal tau function [2] and how does this occur? [1]

A

Tau protein stabilizes microtubules (through four tubulin binding domains)

Microtubules become destabilised by tau when it becomes hyperphosporlated, which decreases its ability to bind to microtubules and disrupts neurons / affects axonal transport

17
Q

Which gene encodes tau? [1]

Are mutations to this gene linked to familial AD? [1]

A

MAPT gene

NOT linked to familial AD; instead to frontotemporal dementia (FTD) and several other Tauopathies.

18
Q

Describe effect of AD on cholinergic pathways? [2]

What can be given to reverse this effect? [1]

A

Cholinergic forebrain pathways innervating cortical and limbic structures degenerate in AD

Blockade of acetylcholinesterase increases the failing cholinergic signal

19
Q

Biomarkers AD

What are current established CSF markers? [2]

A

CSF markers:
Amyloid beta: AB40 and AB42

20
Q

Biomarkers AD

Which imaging types can you use to diagnose AD? [2]

A

Structural MRI
PET (v. costly)

21
Q

Biomarkers for AD

What are potential future blood based biomarkers for diagnosing AD? [1]

A

Tau

22
Q

Treatment strategies in AD

Name the drug class [1] and 3 drug examples you prescribe for mild - moderate AD? [3]

Name the drug class [1] and 3 drug examples you prescribe for severe AD? [1]

A

Mild-Moderate AD:
* Acetylcholinesterase inhibitors(e.g. donepezil, galantamine and rivastigmine)

Severe AD:
* NMDA receptor antagonists (e.g. memantine)

23
Q

Describe the difference in frequency and magnitude of the side effects between memantine and acetylcholinesterase inhibitors (e.g. donepezil, galantamine and rivastigmine)

A

The side-effects of memantine are less common and less severe than for the cholinesterase inhibitors.

They include dizziness, headaches, tiredness, increased blood pressure and constipation (due to wide prevelance)

24
Q

AD can be associated with a slow form of [] due to increased glutamate

A

AD can be associated with a slow form of excitotoxicity due to increased glutamate

25
Q

Which other drugs may AD patients be described based off their symptoms? [3]

But what needs to be considered about these? [1]

A

Antidepressant drugs
Antipsychotic drugs
Mood stabilisers

But overuse of anti-pyschotics can increase in mortality

26
Q

Name 6 potential new mechanisms for AD treatment

A
  • β-secretase inhibitors
  • Notch-sparing γ-secretase inhibitors or modulators
  • Aβ vaccines and monoclonal antibodies
  • Aβ aggregation inhibitors
  • Tau lowering/anti aggregation compounds
  • Regulation of abnormal anti-inflammatory mechanisms