Real Inflammation Flashcards
Inflammation
Response of living vascularized tissue to injury
Goal of inflammation
Remove damaged, necrotic tissues and foreign invaders
Repair
Injured tissue is replaced through
- regeneration of native parenchyma tissue
- by filling of defect with fibrous tissue
- both
Cardinal signs of inflammation
Rubor -redness
Dolor -pain
Calor - fever
Tumor - swelling
Fifth signs of inflammation
Loss of function
2 types of inflammation
Acute and chronic
Acute inflammation
Rapid onset
Short duration ( hours to days )
Exudation of fluid and plasma proteins leading to edema
Emigration of leukocytes , mostly neutrophils
3 characteristics of acute inflammation
> alteration in vascular caliber leading to increased blood flow
> structural changes in micro vascular use to allow plasma cells to get into tissues
> emigration of leukocytes to site of injury , accumulation and activation
Stimuli of acute inflammation
Infections
Tissue necrosis ( ischemia , trauma, mechanical injury )
Foreign Bodies
Immune reaction like in hypersensitivity
Changes in vascular flow and caliber
Transient constriction for few seconds
Vasodilation ( arterioles and then to the capillaries ) => NO and histamine
Increased permeability
Stasis of blood and more viscous blood
Leukocytes adhesion to endothelium and migrations through the wall
Increased vascular permeability
Contraction of endothelial cells
Increased interendothelial cells (histamine, bradykinin, leukotrienes, neuropeptide substance b)
EnDothelial injury
Endothelial cell necrosis and detachment
Transcytosis => increased transport of fluids and proteins
Responses of lymphatic vessels
Lymph flow increased to drain edema
How would you have lymphangitis or lymphadenitis in acute inflammation
Leukocytes , debris and microbes find their way into the lymph during drainage
Lymphangitis
Inflammation of the lymphatic channels because of infection distal to channel
Lymphadenitis
Inflammation of the lymph nodes
Recruitment of leukocytes to site of infections
Margination
Rolling
Adhesion to endothelium
Migration across endothelium and vessel wall (diapedesis)
Migration into tissue towards chemotactic stimulus
Rolling of leukocytes mediators ( receptors on left, ligand on the right )
L-selecting (leukocyte ) —- Glycam-1, CD34 (endothelium)
E-selectin (endothelium ) —- sialyl-lewis X modified protein (leukocytes )
P-selecting (platelet and endothelium ) —- sialyl-lewis X modified protein (leukocytes )
Adhesion of leukocytes mediators (ligand on the right )
VLA-4 integrin (leukocyte ) —— VCAM-1 (endothelium)
LFA-1 integrin (leukocyte ) —— ICAM-1 (endothelium)
MAC-1 integrin (leukocyte ) —— ICAM-1 (endothelium)
VLA-4
Very late antigen 4
LFA-1
Lymphocyte function associated antigen 1
VCAM 1
Vascular cell adhesion molecule 1
ICAM 1
Intercellular adhesion molecule I
Leukocytes migration through endothelium mediators (ligand on right )
PECAM-1 CD31 (endothelium) ——- ligand (leukocyte )
Collagenase (break down basement membrane )
PECAM1 h
Platelet endothelial cell adhesion molecule
Chemotaxis
Locomotion oriented along a chemical gradient produced by chemoattractants
Exogenous chemoattractants
Bacterial products ( peptides with n-formylmethionine) , lipids
Endogenous chemoattractants
Cytokines ( IL8)
Complement system C5a
Arachidonic acid metabolites like leukotrienes B4
Chemotaxis process
Chemotactic agent binds G protein receptor on leukocyte surface
Signal initiated
Secondary message which increases calcium and activate the Rac/Rho/ cdc42
Polymerizatioj of actin induced which increases its quantity at edge of cell
Leukocyte moved by filopodia towards stimuli
Dominant leukocytes during first 6 to 24 hours of acute inflammation
Neutrophils
Leukocyte that replaced neutrophils after 24 hours to 48 hours
Monocytes
Who survive longer neutrophils or monocytesu
Monocytes
Cellular infiltration that do not have same infiltration pattern in acute inflammation
Pseudomonas bacteria - neutrophils dominate for several days
Viral infection - lymphocytes may
Some hypersensitivity rxns- eosinophils dominant
Recognition of microbes and dead tissues by
Toll like receptors
G protein coupled receptors on macrophages, neutrophils and other leukocytes
Receptors for opsinins
Receptors for cytokines
Toll like receptors recognize
Bacteria lipopolysaccharide (LPS)
Bacterial Proteoglycans and lipids
Unmethylated CpG nucleotides
dsDNA viral
G protein coupled receptors on macrophages, neutrophils and other leukocytes recognize…
Small bacterial peptide with n formylmethionyl
Chemokines
Product of complement such as c5a
Lipid mediators
PGs
Leukotrienes
Receptors for opsinins recognize
Antibodies
Complement proteins
Lectins
Opsonization
Coating of particle to make it more disgestable through phagocytosis
Receptors for cytokines recognize
Cytokines (inf-y)
Removal of offending agents in acute inflammation
Phagocytosis : Recognition and attachment Particle engulfment Vacuole formation with particle inside Killing and degradation of particle
In acute inflammation, how is engulfed particle killed
ROS (superoxide ion)
Reactive nitrogen species ( NO, peroxynitrite)
Enzymes like elastase
Microbicidal granules (defensins, lactoferrin, lysozyme, Cathelicidins)
What leukocytes when activated promote proliferation of endothelial cells and fibroblasts , and synthesis of collagen
Macrophages
Leukocytes induced injury
Collateral damage as part of normal defense reaction
In appropriate target of Inflammatory response
Leukocyte induced injury examples
Acute respiratory distress syndrome with neutrophils
Acute transplant rejection by lymphocytes antibodies and complement
Asthma by eosinophils IGE antibodies
Glomerulonephritis By neutrophils monocytes antibodies complement
Septic shock by cytokines
Like abscess by neutrophils and bacteria
Arthritis by lymphocytes macrophages and antibodies
Atherosclerosis by macrophages and lymphocytes
Chronic transplants rejection by lymphocytes and cytokines
Leukocytes genetic defects
Leukocyte adhesion deficiency 1
Leukocyte adhesion deficiency 2
Chronic granulomatous disease=> decreased oxidative burst
X linked => phagocyte oxidase membrane component
Autosomal recessive => phagocyte oxidase cytoplasmic component
MPO deficiency => decreased microbial killing because deficient MPO
Chediak higashi syndrome
Leukocyte adhesion deficiency 1
Mutation in beta chain CD11/CD18 integrans - defective leucocyte adhésion
Genetic defect in leukocytes function
Leukocytes adhesion deficiency 1 leukocyte adhesion deficiency 2 Chronic granulomatosis disease X linked Autosomal recessive MPO Deficiency Chediak higashi syndrome
Leukocyte adhesion deficiency 2
Mutation in fucosyl transferase fr synthesis of sialylated oligosaccharadise - defective leucocyte adhésion
Chronic granulomatosis disease X linked
Decreased oxidative burst due to Phagocytes oxidase (membrane components)
Chronic granulomatosis disease Autosomal recessive
Decreased oxidative burst due to phagocyte oxidase but cytoplasmic component
MPO deficiency
Defect in macrophages causing decreased microbial clearance
Chediak higashi syndrome
Decreased leukocyte function due to mutations
Affect protein involved involved in lysosomal membrane traffic
Acquired defects in leukocyte function
Bone marrow suppression ( tumors , radiation, chemotherapy) - production of leukocyte
Diabetes, malignancy, sepsis , chronic dialysis - adhesion, chemotaxis
Leukemia, anemia, sepsis, diabetes, malnutrition - phagocytosis , microbicidal activity
Mediators of inflammation for termination
Produced in rapid bursts when stimuli present
Short half lives
Degraded after release
Cytokines released by macrophages for anti inflammation response
IL 10
TGF BETA
Anti inflammatory lipid mediators
Resolvins
Protectins
Neural impulses in antiinflammation
Cholinergic discharge
Inhibit production of TNF in macrophages
Types of mediators of inflammation
Cell derived mediators
Plasma protein derived mediators
Cell derived mediators of acute inflammation
Platelets Neutrophils Monocyte macrophages Mast cells Mesenchymal cells ( endothelium, smooth muscle , fibroblasts ) Ahh
Plasma protein derived mediators
Complement proteins
Kinins
Present in blood as inactive precursors
Cell derived mediators that release HISTAMINE
Mast cells
Basophils
Platelets
Histamine action
Vasodilation
Increased permeability
Endothelial activation
Cell derived mediators that release serotonin
Platelets
Role of serotonin
Vasodilation
Increased permeability
Cell derived mediators that release prostaglandins
Mast cell , leukocyte
Prostaglandins role
Vasodilation
Pain
Fever
Cell derived mediators that release leukotriene
Mast cell
Leukocytes
Leukotriene action
Increased vascular permeability
Chemotaxis
Leukocyte adhesion And Activation
Cell derived mediators that release platelet activating factors
Leukocytes
Mast cells
Platelet activating factor role
Vasodilation Increased vascular permeability Leukocyte adhesion Chemotaxis Degranulation Oxidative burst
Cell derived mediators that release ROS
Leukocyte
ROS role
Killing of microbes
Tissue damage
Cell derived mediators that release nitric oxide
Endothelium
Macrophages
Nitric oxide role
Vascular smooth muscle relaxation
Killing of microbes
Cell derived mediators that release chemokines
Leukocytes
Activated macrophages
Chemokines roles
Chemotaxis
Leukocytes activation
Cell derived mediators that release cytokines ( TNF, IL1)
Macrophages
Endothelial cells
Mast cells
Cytokines roles ( TNF , IL1)
Local endothelial activation with expression of adhesion molecule
Fever Pain Anorexia Hypotension Decrease vascular resistance
Fibroblast effects of acute inflammation
Increased : Proliferation of fibroblasts Collagen synthesis Collagenase Protease PGE synthesis
Cell derived mediators that release neuropeptides ( substance P and neurokinin A)
Sensory nerves
Various leukocytes
Role of neuropeptides
Initiation and propagation of inflammatory response
Increase vascular permeability
Pain
Plasma protein derived mediators that release complement products (C5a, C3a, C4a)
Plasma produced in liver
Complement products role
Leucocyte chemotaxis and activation
Vasodilation by mast cell stimulation
Plasma protein derived mediators that release kinins
Plasma produced by liver
Kinin role
Increased vascular permeability
Smooth muscle contraction
Vasodilation
Pain
Proteases activated during coagulation
Plasma
Proteases action
Endothelial activation
Leukocyte recruitment
Classical complement pathway
C1 —> activated C1
Activated C1 —> C4bC2b
C4bC2b —C3 convertase —> C4bC2bC3b
C4bC2bC3b —C5 convertase—> C5-9 MAC complex
Lectin pathway
C1 —mannose binding lectin —> activated C1
Activated C1 —> C4bC2b
C4bC2b —C3 convertase —> C4bC2bC3b
C4bC2bC3b —C5 convertase—> C5-9 MAC complex
Alternative pathway
C3 —> C3b
C3b — factor B and D —> C3bBb —> C3bBb3b —> C5 convertase—> C5-9 MAC complex
Fate of complement activation
Destruction of microbe by leukocytes (C5a, C3a)
Phagocytosis of microbe (C3b)
Mac complex lysis of microbe
Outcomes of chronic inflammation
Complete resolution
Healing by connective tissue (fibrosis )
Progression to chronic inflammation
Morphology pattern of acute inflammation
Dilation small blood vessels
Slowing of blood flow
Accumulation of leukocytes in extra vascular tissue
Accumulation of fluid in extra vascular tissue
Special morphological features of acute inflammation
Serous inflammation Fibrinous inflammation Suppurative or purulent inflammation Abscess Ulcers
Serous inflammation
Outpouring of thin fluid ( effusion) that may be derived from plasma or from secretions of mesothelioma cells lining serous cavities ( peritoneal , pleural , pericardial )
Example of serous inflammation
Skin blister
Fibrinous inflammation
Due to very increase in vascular permeability
Large molecule like fibrinogen pass vascular barrier
Fibrin deposited in extra cellular space
Occurs in large vascular leaks or in presence of procoagulant stimulus
Found in body cavities that
Fibrinous inflammation histology
Fibrin -> eosinophilic mesh work of threads or amorphous coagulum
Fibrinous exudate removal
Fibrin removed by Fibrinolysis
Other debris by macrophages s
What happens if fibrin not removed
Stimulate ingrowth of fibroblast
Leads to scarring
Organization of fibrin
Conversion of fibrin to scar tissue
Suppurative or purulent inflammation
Production of large amount of pus or purulent exudate
Plus contains neutrophils, nécrose cells , edema fluid
Pyogenic bacteria
Bacteria that cause suppurative inflammation with formation of pus
Abscesses
Localized collection of purulent inflammatory tissue due to suppuration buried in tissue
Due to deep seeding of bacteria into tissue
Abscess histology
Central region with mass of necrotic leukocytes and tissue cells
Some of preserved neutrophils around necrosis
Around it , vascular dilation parenchymal and fibroblastic proliferation occur
Fate of abscess
Walled off
Replaced by connective tissue
Ulcers
Local defect, excavation of surface of an organ or tissue
Produced by shedding of inflammatory necrotic tissue
Exist when tissue necrosis and resultant inflammation occur on tissues surface or near it
Most common site of ulcers
Mucosa of the mouth, stomach, intestines , genitourinary tract
Skin and subcutaneous tissue of lower extremeties in older persons
Chronic inflammation
May follow acute inflammation or insidious from onset
Longer duration (weeks or months) with active inflammation, tissue destruction, attempts at repair
Main factors of chronic inflammation
Lymphocytes and macrophages
Proliferation of blood vessels
Fibrosis
Tissue destruction
Conditions with insidious onset of chronic inflammation
Rheumatoid arthritis
Atherosclerosis
Tuberculosis
Pulmonary fibrosis
Causes of chronic inflammation
Persistent infections of difficult microorganism to eradicate
Immune mediated inflammatory disease ( autoimmune disease , unregulated immune response against microbes , response against common substances)
Prolonged exposure to potentially toxic agents
Endogenous ( toxic lipid) , exogenous ( silica)
Morphology of chronic inflammation
Infiltration:
mononuclear ( macrophages , lymphocytes )
plasma cells ( eosinophilia and mast cells )
Tissue destruction ( persistent offending agent or inflammatory cells )
Attempts at healing by connective tissue ( fibrosis )
Proliferation of small blood vessels by angiogenesis
Role of macrophages in chronic inflammation
Help in inflammation and tissue injury : ROS and NOS Proteases Cytokines , chemokines Coagulation factors AA metabolites
Repair : Growth factors Fibrogenic cytokines Angiogenic factors Remodeling collagenesis
Granulomatois inflammation
Distinctive pattern of chronic i
Inflammation
Formation of granulomas in inflammation ( cellular attempt to contain offending agent difficult to eradicate)
Strong activation of T lymphocytes -> macrophages activation
Main disease with granulmatois inflammation
Tuberculosis
Sarcoidosis Leprosy Syphilis Mycotic infections Irritant lipids Autoimmune disorders
Systemic effect of inflammation
Acute phase response : Fever High acute phase proteins ( C reactive protein, fibrinogen, serum) Leukocytosis ( neutrophilia, lymphocytes is, eosinophilia) Leukopenia ( typhoid fever, viruses, rickettsia, protozoa, TB) High pulse High blood pressure Decreased sweating Rigors Chills Anorexia Somnolence Malaise Disseminated intravascular coagulation CDV failure Metabolic disturbance Septic shock
Consequence of defective inflammation
Increased infection
delayed wound healing
Consequence of excessive inflammation
Allergies Autoimmunity Atherosclerosis IHD Neurodégénérative disease like alzheimer