Inflammation & Tissue Repair Flashcards
process of removing harmful agents and beginning repair process
Inflammation
Acute inflammation is part of _____ immunity
Innate
5 steps of acute inflammation
Recognition of threat (DAMPs and PAMPs)
Recruit leukocytes and inflammatory proteins to site
Regulation (innate anti-inflammatory processes)
Resolution
Repair tissue damage
PAMPs are recognized by these receptors on endothelium, dendritic cells, macrophages, and WBCs
Toll-like receptors
Necrotic tissue is recognized by these
Damage-associated molecular patterns (DAMPs)
Examples: uric acid, free DNA, low K+
DAMPs are recognized by these receptors present on all cells
NOD-like receptors
DAMPs are recognized by NOD-like receptor to produce ________
Inflammasome
Inflammasome activates this enzyme
Caspase 1
(which activates IL-1 –> fever and leukocyte recruitment)
Caspase 1 activates this
IL-1 –> fever and leukocyte recruitment
Caspase 1 is involved in this process
DAMPs are recognized by NOD-like receptor to produce inflammasome, which then activates caspase 1 to activate IL-1 –> fever and leukocyte recruitment
= Recognition of threat; begins process of acute inflammatory response
3 main phases of leukocyte recruitment during acute inflammation
Dilation of small arterioles (increase blood flow)
Increased vascular permeability (leakage of protein rich fluid)
Emigration of leukocytes from vessel in tissue
Dilation of small arterioles during acute inflammation is mediated by these
Histamines
Dilation of small arterioles increases or decreases capillary blood flow?
Increases
Increased blood flow leads to redness (rubor) and warmth (color)
____ blood flow allows leukocytes to leave circulation
Slow
Leukocyte margination occurs during acute inflammation due to this
Stasis (slow blood flow)
Leukocyte rolling is mediated by these
Selectins
Leukocyte adhesion to endothelium is mediated by this interaction
Integrin : adhesion molecule interaction
Leukocyte migration across vessel wall occurs in venules toward ______ gradient
Chemokine
Increased vascular permeability occurs via these 2 mechanisms
Endothelial contraction (mediated by histamines, leukotrienes, bradykinins)
Endothelial damage (detachment from basement membrane)
Endothelial contraction causes increased vascular permeability is mediated by these 3 things, and is rapid and short-lived
Histamines, Leukotrienes, Bradykinins
Mechanism of increased vascular permeability that is rapid and short-lived (minutes)
Endothelial contraction
Mechanism of increased vascular permeability that may be long-lived (hours to days); caused by thermal burns, some microbial toxins
Endothelial damage
Increased vascular permeability allows _____ rich exudate to flow into tissues, causing swelling
Protein and cell-rich
Key cell types recruited to site of acute inflammation are:
Phagocytes (neutrophil and macrophage)
Earliest cell to arrive in acute inflammation
Neutrophils
Main cell that arrives at site of acute inflammation
Macrophage
Neutrophils arrive at site of acute inflammation after _____ hours
6-24 hours
Earliest cell
Macrophages arrive at site of acute inflammation after _____ hours
24-48
(later; after neutrophils)
Leukocytes are brought to site of acute inflammation via chemotaxis, mediated by these 4 things
Bacterial production (e.g. LPS)
Cytokines
Complement (especially C5a)
Arachidonic acid metabolites (e.g. leukotriene B4)
Step of acute inflammation that involves innate anti-inflammatory processes
Regulation
Membrane bound threat destruction can involve either of these
Phagolysosome / inflammasome
_______ apoptosis immediately after phagolysosome destruction is involved in the regulation step of acute inflammation
Neutrophil
2 Anti-inflammatory mediators involved in the regulation step of acute inflammation
IL-1:IL-1 receptor antagonist
Bradykinin (kinases)
2 protease inhibitors involved in the regulation step of acute inflammation
Serum alpha-1 antitrypsin
Neutrophil elastase
4 possible outcomes of acute inflammation
Usual outcome is complete resolution
Excess tissue liquefaction –> abscess
Excess tissue necrosis –> tissue removal, replaced with scar
Failure to remove offending agent –> chronic inflammation
Excess tissue liquefaction is a possible outcome of acute inflammation that leads to this
Abscess
Liquefaction necrosis is a possible outcome of acute inflammation that involves _____ surrounded by fibrosis
PMNs (polymorphonuclear leukocytes = neutrophils, basophils, eosinophils)
Term that describes excess tissue liquefaction (pus forming)
Suppuration
Early repaired tissue; early scar
Granulation tissue
Cells that lay down collagen in scar formation
Fibroblasts
Immunodeficiency due to defective Beta chain of neutrophil integrins
Prevents WBC:endothelial adhesion and tissue migration
Delayed umbilical cord separation, followed by omphalitis
Elevated WBC count
Frequent/recurrent indolent bacterial infection
May have skin/other sites necrotizing infection/abscess without pus
Leukocyte adhesion deficiency-1
Elevated WBC count and chronic skin infections with no pus are indicative of this condition
Leukocyte adhesion deficiency-1
3 clinical signs of Leukocyte adhesion deficiency-1
Delayed umbilican cord separation, followed by omphalitis
Elevated WBC count
Frequent/recurrent skin (or other sites) infections without pus
Leukocyte adhesion deficiency-1 is due to defective this
Defective Beta chain of neutrophil integrins
Leukocyte adhesion deficiency-1 prevents this
WBC:endothelial adhesion and tissue migration
(due to defective beta chain of neutrophil integrins)
During phagocytosis, these structures surround and engulf particles into phagosome
Pseudopods
Organelle that produces materials to kill/digest offending agent
Lysosome
These are produced after phagolysosome fusion and during respiratory burst of neutrophils
ROS
How many components does NADPH oxidase have?
7; some in membrane, some in cytoplasm
This process results in the NADPH oxidase components being brought together to form active enzyme
Phagocytosis
Reactive nitrogen and reactive oxygen species are produced during this step in phagocytosis
Phagolysosome fusion
Immune deficiency due to defective phagosome-lysosome fusion
Autosomal recessive mutation of LYST gene
Affects neutrophil granules, melanocyte granules (partial albinism), neuronal axonal vesicle transport (peripheral neuropathy), platelet granules (bleeding disorder)
Neutropenia
Neutrophils and lymphocytes with LARGE fused granules
Delayed microbial killing
Mostly skin/mucosal infections
Bleeding diathesis
Chediak-Higashi Syndrome
Chediak-Higashi Syndrome is due to defective this
Phagosome-lysosome fusion
Chediak-Higashi Syndrome
is caused by an autosomal recessive mutation of this
LYST gene (LYSosomal Traffic regulator)
Chediak-Higashi Syndrome affects these 4 cells
Neutrophil granules (innate immune deficiency)
Melanocyte granules (partial albinism)
Neuronal axonal vesicle transport (peripheral neuropathy)
Platelet granules (bleeding disorder)
Condition characterized by neutrophils and lymphocytes with LARGE fused granules
Chediak-Higashi Syndrome
Condition that can involve albinism, bleeding diathesis, peripheral neuropathy, delayed microbial killing
Chediak-Higashi Syndrome
Mediator of acute inflammation:
Vasoactive amine released by mast cells (preformed and stored in granules)
Released by various stimuli
Causes vasodilation and venule permeability
Histamine
Histamine is released by these cells
Mast cells
2 actions of histamine
Vasodilation and Venule permeability
Mediator of acute inflammation:
Arachidonic acid metabolite
Produced by lipooxygenase in mast cells, other WBCs (preformed and stored in granules)
Causes neutrophil chemotaxis and activation, smooth muscle contraction
Leukotrienes
Leukotrienes are a metabolite of this
Arachidonic acid
Leukotrienes are produced by this enzyme in mast cells and other WBCs
Lipooxygenase
3 actions of leukotrienes
Neutrophil chemotaxis
Neutrophil activation
Smooth muscle contraction
Mediator of acute inflammation:
Arachidonic acid metabolite
Produced by cyclo-oxygenase in mast cells, endothelium, platelets, other WBCs (preformed and stored in granules)
Causes neutrophil chemotaxis and vascular permeability
Prostaglandins
Prostaglandins are metabolites of this
Arachidonic acid
Prostaglandins are produced by this enzyme in mast cells, endothelium, platelets, other WBCs
Cyclo-oxygenase
2 actions of prostaglandins
Neutrophil chemotaxis
Vascular permeability
Lipooxygenase in mast cells and other WBCs produce this mediator of acute inflammation
Leukotrienes
Cyclo-oxygenase in mast cells, endothelium, platelets and other WBCs produces this mediator of acute inflammation
Prostaglandins
Mediator of acute inflammation that causes vasodilation and venule permeability
Histamine
Mediator of acute inflammation that causes neutrophil chemotaxis and activation, and smooth muscle contraction
(Bronchus = bronchoconstriction)
(Arterioles = Vasoconstriction)
Leukotrienes
Mediator of acute inflammation that causes neutrophil chemotaxis and vascular permeability
Prostaglandins
Mediator of acute inflammation that cause:
Endothelial activation
WBC activation
Fibroblast activation
Acute phase response
Induce protein and lipid catabolism; suppress appetite
Cytokines, especially TNF, IL-2, and IL-1
Endogenous pyrogen that sets thermoregulation at higher set-point
IL-2
Complement factors that induce histamine release, leading to vasodilation and permeability
C3a and C5a
Complement factor that leads to chemotaxis of neutrophils, monocytes, eosinophils, basophils
C5a
Complement factor that activates lipooxygenase, which produces leukotrienes and thromboxanes
C5a
C5a activates this enzyme, which produces leukotrienes and thromboxanes
Lipooxygenase
5 cardinal signs of acute inflammation
Rubor: tissue erythema
Calor: tissue warmth
Tumor: tissue swelling
Dolor: tenderness/pain
Functio laesa (loss of function)
Cardinal sign of acute inflammation that describes tissue erythema
Rubor
Cardinal sign of acute inflammation that describes tissue warmth
Calor
Cardinal sign of acute inflammation that describes tissue swelling
Tumor
Cardinal sign of acute inflammation that describes tendernoss/pain
Dolor
prolonged inflammatory response with co-existing tissue injury and repair attempts
Chronic inflammation
4 settings in which chronic inflammation occurs
Persistent infection/injury
Hypersensitivity responses/granulomatous disease
Insoluble toxins (Silica, Beryllium)
Autoimmune disorders
2 main cells of chronic inflammation
Macrophage > lymphocytes (mononuclear cells)
Macrophage becomes M1 cell when T cells secrete this
gamma IFN
Macrophage becomes M2 cell when T cells secrete this
IL-4 and IL-13
When T cells secrete gamma IFN, macrophages become this
M1 cell
When T cells secrete IL-4 and IL-13, macrophages become this
M2 cell
M1 cell produces these
NO and ROS, lysosomal enzymes (innate immunity)
M2 cell produces these
PDGF, FGF (initiates repair process)
2 morphological forms of macrophages
Mononuclear cell (kidney bean shaped nucleus)
Multinucleated forms called Giant Cells
Type of T cells that secrete gamma interferon, activating M1 cells
Th1
Type of T cells that secrete IL-4, IL-5, and IL-13, activating M2 cells (tissue repair) and recruiting eosinophils
Th2
Type of T cells that secrete IL-17, recruiting neutrophils
Th17
Th17 cells secrete IL-17, recruiting these
Neutrophils
Type of T cells involved in bacteria, viruses, and autoimmune diseases
Th1 and Th17
Type of T cells involved with helminths and allergy
Th2
Type of cells that morphologically have small round nuclei, usually scant cytoplasm
Activated forms have more cytoplasm
Lymphocytes
Type of cell that morphologically looks like “glass slippers”
Plasma cells
Type of chronic inflammation against persistent stimuli
Granulomatous inflammation
Granulomatous inflammation is a type of chronic inflammation against this
Persistent stimuli
Cell type involved in granulomatous inflammation
Macrophages
Change in macrophage morphology to epitheliod histiocyte (“banana shape”) occurs during this
May form multinucleated giant cells
Granulomatous inflammation
Released by macrophages and has elevated serum levels granulomatous inflammation
ACE
Released by macrophages during granulomatous inflammation and increases Ca absorption (hypercalcemia)
Vitamin D
How does granulomatous inflammation act to eliminate threats?
Walls off threats
2 typical persistent infections eliminated by granulomatous inflammation
Tuberculosis and Fungi
Granulomatous inflammation often contains this which appears morphologically pink/glassy
Fibrous/hyalinized material
Granulomatous inflammation that is caseating is seen in this infection
Tuberculosis
Immunodeficiency due to NADPH oxidase deficiency
Results in inability to generate superoxide from NADPH
Cannot generate ROS to kill microorganisms
Poor fungal and bacterial killing by neutrophils
Monocytes/macrophages are recruited
Attempt to wall off infection with granulomas
Early childhood onset
Recurrent infections with catalase positive organisms
Pneumonia
Osteomyelitis
Skin infections
Lymphadenitis (lymph node enlargement)
Ineffective phagocyte killing → attempt to contain with granulomas
Also with draining skin nodules
Chronic granulomatous disease
Chronic granulomatous disease is due to a deficiency in this
NADPH oxidase
Cannot generate ROS to kill microorganisms
Condition characterized by ineffective phagocyte killing; attempt to contain with granulomas
Chronic granulomatous disease
In Chronic granulomatous disease, there is ineffective phagocyte killing, so the body compensates by doing this
Attempt to contain infection with granulomas
Condition characterized by early childhood onset, recurrent infections with catalase positive organisms, skin infections, lymphadenitis
Chronic granulomatous disease
3 key cells in tissue repair
Macrophages (M2), fibroblast (collagen), endothelial cell (angiogenesis)
2 processes by which tissue repair occurs
Regeneration
Connective tissue deposition
Describes tissues that are normally continuously regenerating
Surface epithelium, bone marrow
Labile tissues
Tissues that are not dividing but able to stimulate cells to divide
Stem cells, mature cells can re-enter cell cycle
Stable tissues
Tissues that are unable to divide and have no ability to regenerate
Nervous, cardiac muscle
Permanent tissues
2 types of permanent tissues
Nervous and cardiac muscle
2 examples of labile tissues
Surface epithelium and bone marrow
Example of stable tissue
Stem cells
This process of tissue repair depends on proliferative potential of tissue (labile, stable, permanent)
Regeneration
Connective tissue deposition occurs during tissue repair in these 2 settings
Damage is too severe to restore with cellular regeneration
Damage to organ incapable of regeneration (e.g. cardiac)
Connective tissue deposition produces this type of tissue
Granulation tissue - scar/fibrosis
3 components of connective tissue deposition during tissue repair
Angiogenesis (vessels)
Connective fiber deposition
Connective tissue remodeling
4 steps in angiogenesis during connective tissue deposition of tissue repair
Vasodilation (due to NO and VEGF)
Pericytes separate from vessels and breakdown basement membrane
Endothelium migrates to area of injury (pericytes follow)
New vessel is canalized
During angiogenesis, vasodilation occurs due to these 2 molecules
NO and VEGF
Produces increased vascular permeability
NO and VEGF lead to this
Vasodilation; angiogenesis
Cells that separate from vessel and breakdown the basement membrane during angiogenesis
Pericytes
Family of enzymes that digest the basement membrane
MMPs (matrix matelloproteinases)
Cells that separate from vessel and breakdown basement membrane during angiogenesis
Pericytes
M2 cells produce TGF beta, which recruits these cells during connective tissue deposition
Fibroblasts
M2 cells produce this which recruits fibroblasts during connective tissue deposition
TGF beta
Cells which produce TGF beta, recruiting fibroblasts during connective tissue deposition
M2 cells
Granulation tissue that is diffuse or parenchymal
Fibrosis
Granulation tissue that is localized/defined
Scar
M2 cells produce TGF beta during connective tissue deposition, which has these 4 effects
Recruits fibroblasts
Stimulates collagen and fibronectin production
Inhibits MMPs
Inhibits lymphocyte and other WBC activity
M2 cells produce TGF beta during connective tissue deposition, which stimulates the production of these
Collagen and fibronectin
M2 cells produce TGF beta during connective tissue deposition, which inhibits these enzymes
MMPs
M2 cells produce TGF beta during connective tissue deposition, which inhibits these cells
Lymphocytes and other WBC activity
At what point during connective tissue deposition in tissue repair is there granulation tissue?
After connective tissue fiber deposition; where M2 cells have produced TGF beta
Enzymes that are important during connective tissue remodeling of connective tissue deposition in tissue repair and allow collagen turnover
MMPs (matrix metalloproteases)
Type of fibroblasts that produce actin filaments
Myofibroblasts
Cells that are able to contract and reapproximate wound edges togethers during collagen tissue deposition of tissue repair
Myofibroblasts
At what point of collagen tissue deposition of tissue repair is there a mature scar? (dense collagen, mature vessels that are not leaky and have thicker walls)
After connective tissue remodeling
During this part of tissue repair, vessel number decreases, collagen density increases, myofibroblasts produce actin filaments, and WBCs depart
Connective tissue remodeling
Repair process for small wound and minimal separation
First intention tissue repair
Formation of this during first intention tissue repair provides scaffold for repair
Clot formation
Attracts WBCs, fibroblasts, and endothelium
What happens <24 hours during first intention tissue repair?
Neutrophils begin removing necrotic tissue
Epithelium at base begin proliferating
What happens day 3 during first intention tissue repair?
Surface covered by epithelium
Macrophages replace neutrophils
What happens day 5 during first intention tissue repair?
Fibroblasts proliferate and begin type I collagen production
What happens week 2 during first intention tissue repair?
Scar is maturing
What happens at 1 month during first intention tissue repair?
Mature scar without WBCs, tensile strength ~70% of original
At what time of first intention tissue repair does:
Neutrophils begin removing necrotic tissue
Epithelium at base begins proliferating
<24 hours
At what time of first intention tissue repair does:
Surface covered by epithelium
Macrophages replace neutrophils
Day 3
At what time of first intention tissue repair does:
Fibroblasts proliferate and begin producing collagen
Day 5
At what time of first intention tissue repair does:
Scar is maturing
Week 2
At what time of first intention tissue repair does:
Mature scar without WBCs; tensile strength ~70% of original
1 month
Repair process for wound without approximation (i.e. gaping wound; edges are not brought together)
Second intention
4 differences of second intention tissue repair compared to first intention
Gap filled with larger volume of clot and necrotic material
Large volume of granulation tissue fills gap
Larger number of myofibroblasts produced
Produces more prominent scar
Type of collagen that forms provisional matrix during second intention tissue repair
Collegen type III
Type of collagen that replaces the provisional matrix during first intention tissue repair
Type I collagen
Why does second intention tissue repair have higher potential for inflammation-mediated damage and infection?
Gap is filled with larger volume of clot and necrotic material
Healing by second intention often produces this type of scar
Hypertrophic scar
Raised above surrounding tissue
Tissue repair abnormality of excessive fibrous tissue where certain people are predisposed to this
Keloid formation (greatly raised about surrounding tissue)
Keloid formation is more common in people of this origin
African origin
Tissue repair abnormality of excessive fibrous tissue that disturbs organ function
Parenchymal fibrosis
Two cytokines that can lead to production of PG-E2 during fever
IL-1 and TNF
Compound that leads to increased preoptic nucleus set point during systemic inflammatory response syndrome
PG-E2
Occurs when WBCs are released from storage pools and increased production
Leukocytosis
Immune cells elevated in bacterial infection
Neutrophils
Immune cells elevated in viral infection
Lymphocytes
Immune cells elevated in bacterial parasitic infection and allergy
Eosinophils
C-reactive protein, erythrocyte sedimentation rate (ESR), serum amyloid A, hepcidin, and fibrinogen are examples of acute phase reactants that are seen in these states
Inflammatory states