Host Reactions to Biomaterials

Question 1

Effects on implantation

Answer 1

Damage and inflammation inevitable (surgery or implant?)
tissue changes produced chemically or physically
wound healing depends on blood supply

Question 2

Stage of wound healing

Answer 2

Cellular phase
Fibrous phase
resolution/maturation phase

Question 3

Normal inflammation

Answer 3

histamines and prostaglandins released
vasodilation - more WBC and leakage of fluid and cells into connective tissue
graph

Question 4

Wound healing vs implants

Answer 4

surgery < 2weeks, implant > 2w

Question 5

If toxic biomaterial?

Answer 5

longer macrophage and neutrophil stage

Question 6

If implant moves?

Answer 6

longer cellular phase

Question 7

If implant degrades?

Answer 7

longer cellular phase and giant cells

Question 8

If rough surface?

Answer 8

macrophages and GCs remain until smooth

Question 9

Injury/inflammation flow diagram

Answer 9

-

Question 10

Implant-tissue interactions

Answer 10

1 - toxic: kills cells and tissue
2 - bioinert: fibrous, nonadherent capsule around it (thinner is better)
3 - bioactive: adherent interfacial bond occurs with minimal encapsulation
4 - biodeg: dissolution and replaced by host tissue

Question 11

Graph of acute-chronic-granulation

Answer 11

-

Question 12

Chemical mediators of inflammation

Answer 12

vasoactive agents
plasma proteases
leukotrienes
cytokines
growth factors
lysosomal proteases*
O2 derived free radicals*

Question 13

Acute inflammation

Answer 13

emigration of leukocytes

phagocytosis and enzyme release

Question 14

Chronic inflammation

Answer 14

presence of macrophages produces
- chemicals which inhibit fibroblasts making fibre
- proteases, chemotactics, coag factors, cyto, gfs
prolif of blood vessels and connective tissue

Question 15

Granulation (capillary) tissue

Answer 15

fibroblasts and vascular endothelial cells proliferate

collagen fibres align along stress lines

Question 16

FBR?

Answer 16

process
high surface to volume -> mac and GCs
smooth implants -> fibroblasts
material surface chem may control mac adherent apoptosis

Question 17

Fibrous encapsulation

Answer 17

perfect repair of normal structure - stable and labile cells

injured tissue - permanent cells

Question 18

Granuloma

Answer 18

the response to a material which contained a carbon particulate in a polymer matrix
chronic granuloma, 3 months