Foreign Body Response and Encapsulation

Question 1

When does the foreign body response occur?

Answer 1

When materials of non degradable, synthetic, and metallic components are implanted for long-term use

Question 2

How is the foreign body response perceived at the clinical level?

Answer 2

Expected to occur

associated with negative implications for implant longevity

Question 3

Does the foreign body response occur for biodegradable materials?

Answer 3

Only when it has not be designed appropriately

Question 4

Describe the cascade of the foreign body response.

Answer 4

1: Blood-material interaction
2: proteins adsorb and create a film-like deposition
3: cell infiltration of platelets and monocytes
4: the adhered cells release cytokines and chemokine for inflammation response
5: cells are recruited for tissue repair
6: fibrous encapsulation of tissue

Question 5

What is M1 macrophage?

Answer 5

classically activated
pro-inflammatory
pancake, flat structure

Question 6

What is the M2 macrophage

Answer 6

anti-inflammatory
homeostatic
wound healing
wound up structure

Question 7

What is (post) chronic inflammation?

Answer 7

activated when macrophages remain at the implant site
lasts weeks to months
causes granulation tissue formation by depositing ECM with robust angiogenesis at implantation site
If non-degradable, foreign body response begins

Question 8

What is the “foreign body giant cell”?

Answer 8

The fusion of several macrophages to try to eat the massive materials chunk

Question 9

What is encapsulation?

Answer 9

the material is coated in an increasingly dense layer of collagenous connective tissue
causes isolation from surrounding tissue, known as granuloma