DIS - Macular Diseases I: AMD - Week 1 Flashcards
True or false
AMD is the most prevalent macular disorder in Australia?
True
Is the prevalence of AMD projected to increase or decrease? Explain why.
Increase due to growing elderly population
Is AMD a bilateral disease? Explain.
Usually affects one eye, but is a bilateral disease - eventually
What do photoreceptors shed? What happends to these and by what?
Shed outer segment discs
RPE enzymes degrade and recycle them
What happens to light-damaged elements shed by the photoreceptors? What do they form and what do they coalesce to form?
Light damaged outer segment discs cannot be degraded/recycled.
They form lipofuscin vesicles
These coalesce to form BLamD
How can BLamD be visualised?
FAF
Where do BLamD accumulate? What happens to them eventually (forming what)?
They accumulate at the basement membrane of the RPE
They are shed by the RPE and form BLinD
What are druplets?
BLinD
What do druplets coalesce to form?
Drusen
Where does reticular drusen form? Is it more or less serious than other forms of drusen?
Forms at the inner surface of the RPE (interface with the photoreceptors)
More serious
What keeps the choriocapillaris active and what is it produced by?
Kept active by cytokines produced by the RPE
Collectively, what do BLamD, BLinD, and drusen do (2)?
Restrict the RPE, reducing bruch’s membrane flow
What is reticular drusen also known as?
Pseudo-drusen
What happens to BLinD with age? What happens to bruchs membrane alongside this? What consequence does this have?
It thickens
Bruchs membrane takes up cholesterol from the blood - forms plaques
Further restricts clearance and exchange of RPE
Consider what happens to BLinD with age. What happens to the choriocapillaris as a result and what is the consequence of this?
It fails to get PEDF/VEGF and atrophies
What promotes an immune response at bruch’s membrane? List two causes of this. Explain how these two result in either wet or dry AMD.
Lack of proper cytokine/metabolite exhcange:
Genotype for factor H
-increases inflammation, resulting in wet AMD
Complement suppression
-decreases inflammation, resulting in dry AMD
How do cholesterol plaques affect bruchs membrane’s function?
Cholesterol coats BLinD, which reduces BM hydraulic conductivity
What is cholesterol trafficking promoted by and how do genetics of this affect AMD?
Promoted by apo-lipoproteins
People with genetic variants in APoE get faster/worse AMD