Leukocyte extravasation and wound healing Flashcards
Secreted by platelets and macrophages
PDGF
What is the function of TGFß in wound repair?
Stimulates angiogenesis and fibrosis as well as cell cycle arrest
What is the function of FGF?
Stimulates all aspects of angiogenesis during wound repair
Stimulates fibrosis during wound repair
TGFß
Biopsy of a wound one week after injury would reveal a predominance of which type of cell?
Fibroblast
Functions of PDGF
- Vascular remodeling and SMC migration
- Fibroblast growth
What is the function of MMPs during wound healing?
Tissue remodeling
Mediates vascular remodeling
PDGF
Stimulates all aspects of angiogenesis during wound repair
FGF
Stimulates cell growth by acting via tyrosine kinases
EGF
What factors mediate migration?
C5a, LTB4, kallikrein, platelet-activating factor, IL-8
Name a drug that affects leukocyte extravasation
Glucocorticoids (increase PMN count)
What type of collagen is present in a wound from 2 days-1 week
Type III (granulation tissue)
What type of collagen replaces granulation tissue after about a week of wound repair?
Type I (skin)
Mediates cell cycle arrest
TGFß
Name a disease that affects leukocyte extravasation
Leukocyte adhesion defect = defect in LFA1 integrin (CD11/18) on leukocytes so PMNs can’t tightly bind to endothelium
Tissue remodeling during wound repair
MMPs
What adhesion molecules mediate margination and rolling?
E-selectin –> Sialyl-LewisX
P-selectin –> Sialyl-LewisX
GlyCAM-1, CD-34 –> L-selectin
What is the function of EGF?
Stimulates cell growth via tyrosine kinases
Mediates fibroblast growth
PDGF
What secretes PDGF?
Platelets and macrophages
What factors mediate tight binding?
ICAM-1 (CD54) –> CD11/18 integrins
VCAM-1 (CD106) –> VLA-4 integrin
What factors mediate diapedesis?
PECAM-1 (CD31) –> PECAM-1 (CD31)
Where does leukocytes extravasation take place?
Postcapillary venules
What are the steps in leukocyte extravasation?
Margination/rolling
Tight binding
Diapedesis
Migration
