Robbins Ch 3: Inflammation and Repair Flashcards
what are three major components of acute inflammation (AI)
- dilation of small vessels
- increased permeability of microvasculature
- emigration of leukocytes to site of injury
Define exudate and when is it commonly seen?
The escape of fluid, proteins, and blood cells from vascular system into interstitial tissue or body cavities. Commonly seen in site of inflammation.
what is a transudate?
Escape of fluid with low protein content, little or no cellular material, and low specific gravity.
_ results from osmotic or hydrostatic imbalance across vessel wall w/o an increase in vascular permeability.
transudate
Edema results from exudate, transudate or both?
Both
Is pus a transudate or an exudate?
exudate
The changes in vascular flow and caliber as seen during acute inflammation, Vasodilation is mediated by _
histamine, prostaglandins, platelet-activating factor, kinins. But the MAIN player is histamine.
List the following vascular changes and caliber as seen in AI in order:
- Vasodilation
- Vascular permeability
- Stasis
- Leukocyte accumulation
1 –>2 –> 3–>4
Increased vascular permeability is a hallmark of acute inflammation. which vessels are these changes seen in?
Postcapillary venules.
Explain the mechanism via which vascular permeability take place.
- Contraction of endothelial ells resulting in increased interendothelial spaces.
- Endothelial injury, resulting in endothelial cell necrosis and detachment
- Increased transport of fluids and proteins (transcytosis) through the endothelial cell.
What causes the immediate transient response as seen in vascular permeability?
Histamine, bradykinin, leukotrienes and other
What are the mediators of vascular permeability?
Histamine, bradykinin, leukotrienes, and other
Give an example where you’d likely to see delayed prolonged leakage as a sign of acute inflammation.
sun burns.
Give an example of a factor that can cause transcytosis as seen in vascular permeability.
VEGF
List few changes seen in lymphatic vessels, and flow that accompanies AI.
- lymph flow is increased and helps drain edema fluid that accumulates becuase of increased vascular permeability.
- lymphatic vessels proliferate during inflammation
- lymphatic can become secondarily inflamed (lymphagitis)
What is reactive lymphadenitis?
Inflamed lymph nodes and enlargement due to hyperplasia of the lymphoid follicles and increased number of lymphocytes and macrophages.
A patient presents to clinic after an appendectomy. The physician notes red streaks near the skin of the incision. What do the streaks indicate?
Infection. The streaking follows the course of the lymphatic channels and is diagnostic of lymphangitis.
As seen during margination, how does the vascular shear stress change?
Wall shear stress decreases allowing for more leukocytes to assume peripheral position.
What two major family of molecules are involved in leukocyte adhesion and migration?
Selectins and integrins
What molecules mediates the initial rolling interactions as seen in leukocyte recruitment to site of injury and what are their ligands?
selectins (E, L, and P). Their ligands are sialylated oligosaccharides bound to mucin-like glycoprotein backbones.
What cytokines mediates the expression of selectin and their ligands?
Cytokines like NTF, IL1 and chemokines.
What two cytokines specifically induces expression of adhesion molecules on endothelial cells of postcapillary venules adjacent to the injury?
TNF and IL-1
Where are P-selectins stored and what mediates their redistribution from storage to cell surface?
They are stored in Weibel-Palade bodies in endothelial cell granules. Histamine and thrombin stimulates their redistribution to cell surface.
Leukocytes express which selectin and ligands for what selectins?
Expresses L-selectin, and expresses ligands for E and P selectins
What cytokines induce expression of ligands for integrins on endothelial cells?
TNF and IL1 mainly
TNF and IL induce endothelial expression mainly of what ligand for integrin?
VCAM1 - the ligand for beta1 integrin VLA-4
ICAM-1 ligand for beta 2 integrins ILFA 1 and Mac1.
How the integrins VLA-4 and LFA1 get converted from low affinity to high affinity?
Leukocytes normally express integrins in low affinity state. chemokines that were produced at the site of injury bind to endothelial cell proteoglycans and are displayed at high concentrations on endothelial surface. these chemokines bind to and activate the rolling leukocytes which converts VLa4 and FLA1 to high affinity state.
What adhesion molecules present in theintercellular junction between endothelial cells are involved in the migration of leukocytes?
PECAM-1.
What is the most common exogenous chemoattract for Leukocytes?
bacterial products, including peptides that possess an N-formylmethionine terminal amino acid and some lipids
what are some common endogenous chemoattract for leukocytes?
- cytokines like IL-8
- components of complement system, mainly C5a
- Arachidonic acid metabolites mainly Leukotriene B4 (LTB4)
In chemotaxis of leukocytes, leukocyte moves by extending _
filopodia
What are some phagocytic receptors that are used to attach to particle to be ingested by leukocyte/
- mannose receptors
-scavenger receptors
receptors various opsonins
Explain how the macrophage mannose receptor is able to bind only to microbes and not mammalian cells.
Macrophage manose receptor is able to bind terminal mannose and fructose residues of glycoproteins and glycolipids. these sugars are typically part of molecules found on microbial cell walls. Mammalian glycoproteins and glycolipids has sialic acid or N-acetylgalactosamine.
What do scavenger receptors bind?
Originally thought to find LDL that can no longer bind to it’s own receptors, but can bind to variety of microbes.
Name a macrophage integrin that binds microbes for phagocytosis
Mac-1 (CD11b/ CD18)
What are some common opsonins that facilitate recognition by phagocytes
- IgG antibodies
- C3b
- Plasma lectin notably mannose-binding lectin
_ system is considered the most efficient bactericidal system of neutrophils
H202-MPO-halide
H202 cannot kill on it’s own, what enzyme found in neutrophils make it a potent killer by combining with a halide?
myeloperoxidase
How does peroxynitrite kill microbes?
Attacks and damage lipid proteins and nucleic acids
Which neutrophil granules contains myeloperoxidase?
Primary granule (aka larger azurophils)
Which lymphocytes has a role in acute inflammation and the absence of which prones individuals to infections by fungi and bacteria?
TH17 which produces IL17
What molecules (factors, cytokines etc) are known to inhibit /terminate inflammation?
- Lipoxins
- TGF-beta
- IL-10
What is the source of histamine and what are its actions?
Source: mast cells, basophils, platelets
Action: vasodilation, increased vascular permeability, endothelial activation
What are the sources of prostaglandins and what are its actions?
Source: mast cells, leukocytes
Action; Vasodilatio; pain, fever
What are the sources of Leukoctrienes and what are its actions?
Source: mast cells, leukocytes
Actions: increased vascular permeability, chemotaxis, leukocyte adhesion, and activation
Cytokines (TNF, IL-1, IL-6), source and action
Source: macrophages, endothelial cells; mast cells
Actions: Local: endothelial activation. Systemic: fever, metabolic abnormalities, hypotension
What are the sources and action of chemokines?
Source: leukocytes, activated macrophages
Action; chemotaxis, leukocyte activation
What are the sources and actions of platelet-activating factor?
Source: Leukocytes, mast cells
Action; vasodilation, increased vascular permeability, leukocyte adhesion, chemotaxis, degranulation, oxidative burst
what are the sources and actions of comlements?
Source: liver
Action: leukocyte chemotaxis and activation, direct target killing (MAC), vasodilation
what are sources and action of kinins?
Source: Plasma (liver)
Action; increased vascular permeability, smooth muscle contraction, vasodilation, pain