Acute Inflammation Flashcards
1
Q
Acute phase protein (APP) defined as
A
- Protein whose concentration increases (pos. APP) or decreases (neg. APP) by 25% or more during inflammatory processes or disorder
2
Q
Acute phase proteins (APP) synthesized where
A
- Most synthesized in the liver (except gamma globulins; from plasma cells)
3
Q
APP regulated by
A
- Inflammatory cytokines *IL-6, IL-1Beta, TNF-alpha - Most regulated primarily at transcriptional level, but some post-transcriptional and transnational changes as well
4
Q
Clinical relevance of APP
A
- Reflect the presence and intensity of an inflammatory process - Useful as a diagnostic aid, helping to differentiate inflammatory from non-inflammatory conditions
5
Q
APP that rise the most after inflammatory stimulus
A
- C-reactive protein - Serum amyloid A
6
Q
Serum vs. Plasma
A
- Plasma still has active clotting factors *Inactivating them leaves you with serum
7
Q
Alpha 1 globulin
A
- alpha1- Antitrypsin
8
Q
Alpha 1/Alpha 2 globulins
A
- Ceruloplasmin
9
Q
Alpha 2 globulins
A
- Haptoglobin - alpha 2-macroglobulin
10
Q
Beta 1 globulin
A
- Transferrin
11
Q
Beta 2 globulin
A
- Fibrinogen
12
Q
Globulins increased during infection
A
- alpha 1 - alpha 2
13
Q
Alpha 1 antitrypsin deficiency
A
- Emphysema (adults) - cirrhosis (juvenile)
14
Q
C-reactive protein (CRP) elevated during
A
- Chronic inflammatory conditions - Cancer
15
Q
CRP regulation
A
- At the transcriptional level: IL-6 induces, other cytokines act synergistically to increase response
16
Q
CRP functions
A
- part of innate immune response - Ca++ dependent binding of phosphocholine (PCh) *PCh present on cell membranes of bacterial and fungal pathogens - Binds nuclear components of apoptotic or necrotic cells - Ligand-bound CRP is bound by C1q and activates the classical complement pathway - CRP may also help recruit phagocytes by binding Fc receptors
17
Q
Lower elevated levels of CRP are associated with
A
- Increase cardiovascular risk
18
Q
Serum amyloid A structure
A
- Family of apolipoproteins, some acute phase reactants, some constitutive - Contains alpha helix w/ beta pleated sheets
19
Q
SAA regulation
A
- Levels increase within hours of stimulus - Magnitude of increase may be larger than CRP - Induced by synergistic action of cytokines *IL-1, IL-6
20
Q
SAA function
A
- Precursor of amyloid A protein, major component of secondary amyloid plaques - Associates w/ HDL, replacing apolipoprotein A-1 *This is going to induce reverse cholesterol transport - Reduces storage of cholesterol esters in macrophages (decrease foam cells)
21
Q
Altered properties of acute phase HDL
A
- Cleared from the circulation more rapidly - 5x increased binding to macrophages - Enhanced uptake of HDL by macrophages
22
Q
Fibrinogen regulation
A
- Made in hepatocytes - Moderate APP - induced by IL-6, glucocorticoids, oncostatin-M Abundant in plasma, elongated shape, greatest effect on ESR - Allows the platelet to coagulate
23
Q
Fibrinogen and its cleavage products functions
A
- Immunosuppression - Proliferation - Haemostasis - Blood vessel tone - Angiogenesis - Cell migration
24
Q
Erythrocyte Sedimentation Rate (ESR)
A
- Blood + anti-coagulant placed in vertical tube and measure rate of fall - Measures the distance that a vertical column of anticoagulated blood has fallen in one hour - Most widely used marker of inflammation - Indirect measure of APP, especially fibrinogen - Increased aggregation of rbc causes them to fall faster - Increased by high immunoglobins - changes in rbc size, shape can affect ESR - Progressive increase w/ age
25
Alpha 1- antitrypsin structure
- Single- chain protein w/ 3 oligosaccharide side chains - Over 75 plymorphic forms
26
Alpha 1- antitrypsin regulation
- Most made in liver, ~1% in monocytes - Levels increase 3-4 fold in acute phase - Induced by IL-6
27
Alpha 1- antitrypsin function
- One of the compensatory molecules that will limit the damage that takes place during acute inflammatory events - Inhibits trypsin, elastase, other proteases by forming inactive complexes \*blunts the effect of quite a few of the extracellular components that neutrophils release - Protects elastic fibers in lung alveoli from excessive digestion by neutrophil elastase
28
Deficiency of AAP causes
- Emphysema - Cirrhosis
29
Alpha 2-macroglobulin structure and properties
- Very large glycoprotein w/ 4 identical subunits - Comprises 8-10% total plasma protein
30
Alpha 2-macroglobulin regulation
- Synthesized by hepatocytes, monocytes, astrocytes - Relative levels increased in nephrotic syndrome, due mainly to large size
31
Alpha 2-macroglobulin function
- Panprotease inhibitor \*limits the collateral damage that some of the inflammatory mediator cells are going to do; plays a direct role at the site of inflammation - Transports ~10% of zinc in plasma (albumin transports the rest) - Binds cytokine and growth factors, appears to target them to particular cell types
32
Transferrin structure and properties
- Beta globulin - Negative acute phase protein - Single-chain glycoprotein w/ 2 binding sites for Fe3+
33
Transferrin function
- Carries Fe in blood - Presence of unbound sites protects against infection by Fe-dependent pathogens - Level of saturation changes w/ Fe availability \*TIBC (transferrin iron binding capacity) increases in Fe deficient states
34
Ferritin
- 24 subunits surround a core of 3-4000 Fe3+ - 2 subunit isoforms, L and H - Mostly in tissues, but small amount in blood=indicator of Fe reserves
35
Haptoglobin
- Alpha 2 globulin - Pos. APP - Antioxidant properties - Binds extra-corpuscular HB - Stimulates angiogenesis
36
Albumin
- Small but very abundant - Accounts for 50-60% of protein in plasma - Responsible for 80% osmotic pressure of blood - Represents 25% of total protein synthesized in liver - Neg. APP - Rate of synthesis depends on nutritional status - Transports numerous substances in blood
37
Transthyretin (prealbumin)
- Migrates slightly ahead of albumin during electrophoresis - Neg. APP - Transports Vit. A (retinol) and thyroxine (though most transported by thyroxine binding protein) - Inhibits IL-1 production by monocytes and endothelial cells
38
Lukotrienes
- Arachidonic acid metabolite
- Product of lipoxygenase
- 5 LO (neutrophils): 5-HETE
- Precursor of leukotrienes (LTC4, LTD4, LTE4); vasoconstriction and bronchospasm
39
Lipoxins
- Arachidonic acid metabolite
- Leukocytes + platelets
- Inhibit neutrophil adhesion and chemotaxis
40
Cyclooxygenase
- Arachidonic acid metabolite
- Generate prostaglandins
\*product of mast cells, endothelial cells, and macrophages
41
PGD2
- Prostaglandin
- Secreted by mast cells
- Vasodilation and increases vascular permeability
- Chemoattractant for neutrophils
42
PGE2
- Prostaglandin
- Secreted by many cell types
- Vasodilation and increases vascular permeability
43
ThromboxaneA2
- Prostaglandin
- Secreted by platelets
- Vasoconstriction and promotes platelet aggregation
44
eNOS
- Produced constitutively by endothelium
- Down regulates or limits leukocyte adhesion by down regulating the cell surface molecules that would assoc. w/ endothelial cells
- Short acting
45
iNOS
- Produced by macrophages
- Complex w/ROS to generate reactive nitrogen species as well as all the other antimicrobial intermediates that macrophages produce
46
Nitric oxide
- Product of nitric oxide synthase (NOS) acting on L-arginine
- 3 forms of NOS
\*eNOS
\*nNOS
\*iNOS
- Endogenous compensatory mechanism that reduces inflammatory responses
\*primarily eNOS
- NO production is enhances in response to microbial infection
\*primarily iNOS
47
TNF principal sources and role in inflammation
- Sources
\*Macrophages
\*Mast cells
\*T lymphocytes
- Role: Stimulates expression of endothelial adhesion molecules and secretion of other cytokines; systemic effects
48
IL-1 principal sources and role in inflammation
- Sources:
\*Macrophages
\*Endothelial cells
\*Some epithelial cells
- Role: Similiar to TNF; greater role in fever
49
IL-6 principal sources and role in inflammation
- Sources:
\*Macrophages
\*Other cells
- Systemic effects (acute-phase response)
50
Chemokines principal sources and role in inflammation
- Sources:
\*Macrophages
\*Endothelial cells
\*T lymphocytes
\*Mast cells
\*Other cell types
- Role: Recruitment of leukocytes to site of inflammation; migration of cells to normal tissues
51
Cytokines in acute inflammation
- TNF
- IL-1
- IL-6
- Chemokines
52
Cytokines in chronic inflammation
- IL-12
- IFN-y
- IL-17
53
IL-12 principal sources and role in inflammation
- Sources:
\*Dendritic cells
\*macrophages
- Role: Increased production of IFN-y
54
IFN-y principal sources and role in inflammation
- Sources:
\*T lymphocytes
\*NK cells
- Role: Activation of macrophages (increased ability to kill microbes and tumor cells)
55
IL-17 principal sources and role in inflammation
- Sources:
\*T lymphocytes
- Role: Recruitment of neutrophils and monocytes
56
Principal mediators of inflammation