Lecture 6 - Inflammation and repair Flashcards
4 things that cause fibrosis to be favored over regeneration
- severe/prolonged injury
- loss of basement membrane
- large amounts of exudate
- lack of renewable cells (non-dividing)
most tissues have a __ cell population of cells with latent capacity to regenerate, if tissue is damaged the neighboring cells can leave G0, divide and migrate to replace
stable
__ do not enter G0 (quiescent) state/they continue to multiply throughout life, these cells have lots of repair compacity
labile
3 examples of labile cells
epithelial, hematopoietic, and lymphoid cells
5 examples of stable cells (can divide and migrate)
- epithelial cells in lung, liver, kidney, endocrine glands
- endothelial cels
- fibroblasts
- smooth m
- +/- skeletal m
non-dividing cells do not have the capacity to __ they only have limited capacity to regenerate portions of cell cytoplasm post injury. give 2 examples!
divide, cardiac myocytes and neurons
only repair for non-dividing cells of the heart and neurons is by
scarring
4 stem and progenitor cells in tissues
- skin - hair follicle bulge stim cells and interfollicular epidermal stem cells
- intestinal crypt stem cells
- liver oval cells
- eye corneal stem cells
4 things that favor regeneration over scarring
- mild/brief injury
- maintenance of basement membrane/microvascular/tissue framework
- SMALL amounts of exudate
- renewable cells (dividing progenitor/stem cells)
healing by __ there is little exudate and tissue elements are close (no large gap)
first intention
healing by __ the edges of wound are wide apart, damaged area contians exudate and necrotic debris, fills in with granulation tissue but leaves large area of fibrosis (scar)
second intention
__ is the replacement of fibrin and necrotic debris by granulation tissue
organization
__ is highly organized form of fibrovascular tissue with orderly episodes of mac influtration, stimulation of angiogenesis and fibrosis and maturation to dense c.t. scar
granulation tissue
__ in horses is an example of exuberant granulation tissue producing proliferative lesions
proud flesh
is granulomatous inflammation the same as granulation tissue
NO
2 consequences of fibrosis
- loss of functional parenchyma
2. alteration of tissue physical properties (prone to tearing, less compliant)
4 zones of granulation tissue
- necrotic debris and fibrin
- macs and ingrowing caps
- prolif caps and fibroblasts
- maturing fibrous c.t. (scar tissue)
__ refers to fibrin exudate, __ refers to collagen rich c.t. repair process
fibrinous, fibrous
__ inflammation dominated by macs, __ is a type of repair process where an injury gets filled in and organized
granulomatous, granulation
what factors promote angiogenesis
VEGF, bFGF, PDGF
what factors are important in deposition and remodeling of ECM
TGF beta, PDGF, TNF, IL1, collagenase, MMPs
6 things that promote fibroblast migration/replication and collagen synthesis
- PDGF (Platelet derived GF)
- EGF (epidermal GF)
- FGF (Fibroblast GF)
- TGF beta (Transforming GF)
- TNF alpha (Tumor necrosis factor)
- IL1
3 things that promote epithelial proliferation and migration
- EGF (epidermal GF)
- HGF (hepatocyte gf)
- KGF (keratinocyte GF)
3 things that promote angiogenesis
- VEGF (Vascular endothelial gf)
- FGF (fibroblast gf)
- PDGF (platelet derived gf)
__ promotes granulation tissue formation (increase keratinocyte and firboblast prolif/migration)
EGF alpha (epidermal GF) - from platelets and macs
__ increases epithelial proliferation and cell scattering/migration
HGF (hepatocyte GF, scattor factor) - from fibroblasts, platelets and endothelial cells
__ increases epi cell (keratinocyte) migration, prolif, and differentiation
KGF (keratinocyte GF) - from fibroblasts
what factors are from fibroblasts
KGF and HGF
What factors are from platelets
EGF, HGF
What factros are from macs and platelets
EGF
__ increases chemotaxis (fibroblasts), synthesis, angiogenesis and wound contraction
PDGF (platelet derived gf)
__ activates macs and promotes fibrosis (stimulate fibroblast and collagen synthesis)
TNF alpha
__ is chemotactic for fibroblasts (and other cells), increases collagen syn, TIMP, TGF beta and DECREASES peithelial growth
TGF beta (transforming gf)
__ promotes angiogenesis, stimulates epithelial cell migration, chemotactic for firbobalsts
B-FGF
__ increases angiogenesis and vascular perm
VEGF
EXAM: What are potent inducers of angiogenesis
VEGF, BFGF, PDGF