Amyloidosis

Question 1

What are the four main types of amyloid?

Answer 1

• Amyloid light chain (AL): derived from immunoglobulin light chains (λ, κ),
  associated with immunoglobulin-secreting cells (plasma cells)
• Amyloid-associated (AA): derived from serum amyloid A (SAA)synthesized in the
  liver and released during systemic inflammation
• A-β: derived from amyloid precursor protein (APP), associated with amyloid
  angiopathy in Alzheimer’s and some forms of canine neurodegeneration
• Islet Amyloid: derived from islet amyloid polypeptide (IAPP), synthesized by the β
  cells of the pancreatic islets

Question 2

What is primary amyloidosis associated with?

Answer 2

associated with immune cell dysfunction (plasma cell tumours)

Question 3

What is secondary amyloidosis associated with?

Answer 3

associated with chronic inflammation or tissue destruction; can
be associated with autoimmune conditions that result in chronic inflammation

Question 4

What two clinical conditions are associated with primary amyloidosis?

Answer 4

• Monoclonal gammopathy on serum protein electrophoresis
• Bence-Jones proteins: light chains are small, can be filtered into urine

Question 5

What is secondary amyloidosis also called?

Answer 5

reactive systemic amyloidosis

Question 6

How does the pathogenesis of secondary amyloidosis usually begin?

Answer 6

It starts with the production of amyloidogenic proteins prone to misfolding
The proteins are normally degraded, but the degredation process is inadequate

Question 7

What usually causes death in secondary amyloidosis?

Answer 7

Usually due to renal failure

Question 8

What is familial amyloidosis?

Answer 8

• AA form, hereditary in some dog and cat breeds
• Abyssinian cats, Shar Pei dogs
• Primarily deposits in kidneys, lesser extent in liver
• Glomerular distribution in cats, medullary in dogs

Question 9

What is aging amyloidosis?

Answer 9

• Usually A-β form, cerebrovascular amyloidosis in old dogs
• May also deposit in heart, GI tract, lungs