Week 1 Inflammation Flashcards
Blood cells involved in inflammation
Neutrophils, Eosinophils, Basophils, Monocytes, Lymphocytes, Platelets,
ENDOTHELIAL cells, basement membrane, and Smooth Muscle cells.
Connective tissue cells involved in inflammation
Mast cells, Fibroblasts, Macrophages, Lymphocytes
Plasma proteins involved in inflammation
Coagulation proteins, Kinins, Fibrinolytic enzymes
Duration and main characteristics of Acute Inflammation
1 week max.
Edema fro increased blood flow and vascular permeability, exudate.
Leukocyte emigration to site of inflammation
Rubor, Tumor, Calor, Dolor
Redness, Swelling, Heat, Pain
Loss of function
What are the advantages of exudation to a wound site?
Dilution of toxins
Increased protein content –> Increased Immunoglobulin
What are the advantages of exudation to a wound site?
Dilution of toxins
Increased protein content –>
- Increased Immunoglobulin
- Fibrin nets, fixing bacteria and wound healing
- Acute phase proteins
What are 4 methods of vascular leakage
Endothelial cell contraction in small venules - histamine, bradykinin, leucotrienes.
Occurs rapidly and is short lived.
Junctional retraction - IL-1, TNFa, IFNy
-delayed effect after 4-6 hours.
Leokocyte-dependent leakage
- leukocyte-produced proteolytic enzymes and free radical increase permeability
Leakage from regenerating/damaged capillaries
-increased leakage as angiogenesis occurs and vessels aren’t sealed tightly.
Stages and mediators of extravasation
1) Rolling. P-selectins bind endothelial glycoproteins
P-Selectin on leukocytes — P-selectin glycoprotein ligand-1 on Endothelial cells
VLA-4 also
2) Slow rolling. Shorter, higher affinity E-selectins bind glycoproteins
E-Selectins
3) Slow rolling allows for chemokine signaling to increase as they move through the inflamed region
4) Firm Adhesion. Leukocyte Integrins bind endothelial GAGs on endothelial Cell Adhesion Molecules (glycoproteins).
VLA1 —- VCAM1
(Very Late Antigen 1)
LFA1 —- ICAM1
(Leukocyte Function-associated Antigen 1)
5) Extravasaion/Diapdesis
Also involves cell adhesion molecules and integrins: LFA1, VCAM1, ICAM1, ICAM2
Exogenous substrates (from pathogens) that activate leukocytes
PAMPs and DAMPs, bound by C-type lectins, and TLRs TLR1, 2, 4, 5, 6, which can be Endosomal or Cell Surface receptors
Pathogenic associated molecular patternsm, PAMPs:
From GrPos bact: G+ cell wall peptidoglycan, lipoteichoic acid
From GrNeg bact: LPS
From either: Flagellin, N-formylmethionine, hypometheylated CpG-DNA, free single or double stranded DNA or RNA
Damage associated molecular patterns, DAMPs:
Components of cells that should be intracellular but are encountered by the macrophages in the environment (from lysed/dead cells)
Nuclear proteins
Mitochondrial DNA
Oxygen radicals
Heat shock proteins
What are endogenous substrates that activate leukocytes?
IL-8
Lipoxygenase productes LTB4
Complement proteins C5a, C3a
What is the receptor expressed on phagocytes that binds opsonized microbes and induces phagocytosis?
What is its ligand?
Receptor: Fc-gamma receptors FcyRs
Ligand: C3b and Fc-fragment of IgG in complex
What are the two pathways of that can initiate phagocytosis?
Opsonin mediated pathway: binding opsonized, antibody bound microbes
Nonspecific pathway: PAMPs
What are the stages of phagocytosis?
What are the two major pathways used to kill target microbes?
1) Recognition and binding
binding PAMPS or opsonized antibody complexes
2) Englufment
Surrounding, Fusion of phaocytic and lysosomal granules onto the target microbe membrane
3) Killing Oxygen dependent: NAPDH oxidase --> Superoxide ion --> H2O2 MPO --> H2O2 + Cl- --> HOCl NO synthase --> Peroxinitrite
Oxygen indepdendent lysozymes lactoferrin MBP, Major basic protein Defensins - pore forming proteins Acid hydrolase
What are some types of Acquired Defects in leukocyte functions? ie, what can disrupt chemotaxis, phagocytosis, microbe killing ability
Burns, Malignancy, Sepsis, AIDS –> disrupt chemotaxis
Hemodialysis –> disrupts leukocyte adhesion
Leukemia, Anemia, Sepsis, Malnutrition, and Neonatal period –> disrupts phagocytosis and microbiocidal ability
Diabetes –> disrupts chemotaxis, adhesion, phagocytosis and killing ability
What major inflammatory cytokines initiate the Acute Phase Reaction?
What other major event do these cytokines initiate?
IL-1
IL-6
TNFa
Stimulate Fever, by activating the hypothalamic regions responsible for inducing fever.
What is the Acute Phase Response? (APR)
What can stimulate it?
The changes in protein expression primarily caused by altered expression in the liver, induced by inflammatory cytokines that are released from innate immune cells.
Stimulated by:
Trauma/Injury, Infection, Stress, Neoplasia, or Inflammation