9/20 Flashcards
Cardinal Signs of Inflammation explained by Chemicals
1-2. Rubor/calor: vasodilation increases blood flow
Histamine, prostaglandins, and bradykinin relax arteriolar smooth muscle
- Tumor: fluid leakage from venules into interstitium (exudate)
Histamine causes endothelial cell contraction
- Dolor: bradykinin and PGE2, sensitive nerve endings
- Fever: pyrogens (LPS) cause IL-1 and TNF-alpha release from macrophage, increased cyclooxygenase activity in hypothalamus
Increased PGE2 raises temp. set point
Mediators of Endothelial Cell Activation
- Early activators: histamine, bradykinin, PAF, thrombin
Promote vasodilation and permeability
- Late Activators: IL-1beta, TNFalpha, IFNgamma
- Other mediators: Complement, bacterial products, hypoxia, viruses, prostaglandins, leukotrienes
Consequences of Endothelial Cell Activation
Transient vasoconstriction from endothelins, thromboxane, and angiotensin II
Vasodilation of precapillary arterioles that is caused by NO, PAF, bradykinin, PGI2
Increased vascular permeability, fluid and cells leave circulation
Release cytokines like IL-8 that promote neutrophil activation
Contraction of cytoplasmic myosin occurs early due to histamine, bradykinin, and leukotrienes, increase vascular permeability by increasing gap between endothelial cells
Retraction of cytoskeletal elements occurs later due to IL-1, INF-gamma, TNF-alpha
Transudate vs. Exudate
- Transudate: low protein content, essentially no leukocytes, no endothelial cell damage, clear liquid
Due to decreased protein synthesis like liver disease or increased protein loss like kidney disease
Allergic dermatitis, herpes
- Exudate: high protein content, has some WBCS and RBCs
Due to inflammation that causes vasodilation and increases interendothelial spaces, has Endothelial Cell damage
Cloudy liquid, fibrin rich, purulent, sanguineous
Starling’s Law and how Inflammation Impacts it
- Increased vascular permeability: slight increase in K
- Interendothelial gap formation: slight increase in K
Involves early contraction of cytoplasmic myosin that is then balanced later by a late retraction of cytoskeletal elements
- Direct Endothelial Cell Injury: large increase in K, severe monophasic increase in permeability
May be direct injury to vessel and can be fast/long lived
May be leukocyte-dependent injury, mostly venules/pulmonary capillaries, late response and is long lived
Steps in Neutrophil Arrival
- Margination: hemoconcentration where RBCs group in middle of vessel, WBC margination, vasodilation slows blood flow
- Rolling- Selectins (speed bumps) upregulated
P-selectin: Weibel-Palade bodies store them on ECs, released by histamine
E-selectin: induced by TNF and IL-1 - Adhesion: cellular adhesion molecules upregulated on endothelial cells by TNF and IL-1, integrins upregulated on leukocytes by C5a, CAM-Integrin interaction results in firm adhesion of leukocytes to endothelial cells
- Transmigration and chemotaxisneutrophils attracted by bacterial products, IL-8, C5a, LTB4
- Phagocytosis
- Resolution: neutrophils do apoptosis and die within a day of inflammation resolution
Cell Adhesion Molecules
P selectin on EC binds to leukocyte mucin carbs like sialyl-Lewis X residues, activated by histamine, PAF, and thrombin
E-selectin upregulated due to TNFalpha and IL-1beta
Integrins on leukocytes bind to ECM, VCAM-1, fibronectin, and fibrinogen
CAMs from immunoglobulin superfamily stimulated by TNFalpha and IL-1beta
Chemokines Dependent Leukocyte Activation
Low avidity integrins on Leukocyte bind to receptors on endothelial cell with chemokines on proteoglycans on cell surface
Activated ECs from TNF and IL-1 express new CAMs that bind to the high avidity integrins on activated leukocytes
Integrins are heterodimeric proteins
Leukocyte Paracellular Transmigration
Intracellular Adhesion molecule 1 (ICAM1) on EC binds macrophage antigen 1 (MAC1)
Triggers increased intracellular Ca2+, RHO, and p38 MAPK to increase myosin contractility and EC contractility
Beta-1 integrin and other proteases on Leukocyte help transmigrated between cells
Leukocyte transcellular transmigration
Go through thin parts of EC with actin and caveolae-rich regions, ICAM1 containing caveolae link together to form vesiculo-vacuolar organelles to form an intracellular channel, ERM proteins provide structural support between ICAM1 and EC actin
Go through pericyte gaps, may need MMP and neutrophil elastase activity to help move through basement membrane
Chemotaxis
Go along conc. gradient of chemotactic factors like C5a, IL-8, and PAF
Rapid actin polymerization at leading edge of leukocyte’s filopodia, integrins on surface help facilitate movement
NSAIDs basics
2 types: non-selective and selective/COX-2 inhibitors
Inhibition of COX-1 causes GIT toxicity, PGE has protective effects on gastric mucosa
COX-1: prostaglandins and thromboxanes
Gastroprotectiin, platelet aggregation, renal function
COX-2: prostaglandins
Pain, fever, renal function, tissue repair, reproduction, development
NSAIDs Types
COX-1/2 Inhibitors-
Aspirin
Ibuprofen: Motrin, Advil, osteoarthritis, rheumatoid arthritis
COX-2 Inhibitors-
Celecoxib: Celebrex, inflammation, osteoarthritis, rheumatoid arthritis
Meloxicam
Patent Ductus Arteriosus
Congenital heart disorder where neonate’s ductus arteriosus fails to close after birth
PDA remains open (patent), have improper mixing between oxygenated aorta blood and deoxygenated pulmonary artery blood
Congestive heart failure if untreated
Prostaglandin E1 keeps the ductus patent, use NSAIDs like indomethacin to help close
NSAIDs Pharmacological Effects
Analgesic
Antipyretic
Anti-inflammatory
Some are uricosuric
GIT damage like ulcers/gastritis (lack PGE1)