FTK 3: Amyloid

Question 1

amyloid

Answer 1

deposition of proteinaceous substances in extracellular space that causes either interruption of cell function or atrophy during disease

Question 2

light chain amyloid

Answer 2

= made up of monoclonal immunoglobulin (Ab) light chains

seen in…
1. plasma cell dyscrasias
2. plasma cell tumors
3. Equine nodular cutaneous amyloidosis

NOT RELATED TO INFLAMMATION

Question 3

3 characteristics of amyloid

Answer 3

(1) Smooth to fibrillar and eosinophilic (pinkish) using H&E

(2) Stains red with Congo red stain and has apple-green birefringence when viewed with polarized light

(3) Molecular structure is a beta-pleated sheet, which makes it resistant to enzymatic degradation

Question 4

secondary amyloid

Answer 4

SAA (serum amyloid-associated protein) released by the liver as an acute phase protein

seen after chronic antigenic stimulation or chronic inflammation

pathogenesis
1. SAA released into circulation after chronic inflammation

2. taken up by macrophages and metabolized into amyloid
3. deposited into extracellular space and causes atrophy/cell dysfunction
   Liver = space of Disse
   Kidney = affects glomerulus or deposited in interstitium
4. can also cause HYPOXIA if blocking blood flow to organ

Question 5

islet amyloid

Answer 5

beta cells in the pancreas co-secrete insulin with a precursor polypeptide to sit in the interstitial of pancreatic islets

often seen in older cats with diabetes mellitus