Pathology

Chemical mediators of inflammation and the

inflammatory response. Session 2

7th Lecture

Dr. Ahmad H. Ibrahim .

PhD. University of Science Malaysia USM Malaysia MSc . University of Science Malaysia USM Malaysia

Objectives

1. To learn the basic of Chemical mediators of inflammation.

2. To know about the source of chemical mediator.

3. To recognize the stimulates production of mediators?

4. To study the clotting system.

What stimulates the production of mediators?

• Microbial products • Necrotic debris

Properties of Chemical Mediators • Specific stimulus • Short lived • Cascade reaction

1. Vasoactive Amines A substance containing amino groups, such as histamine or serotonin, that acts on the blood vessels to alter their permeability or to cause vasodilation.

A. Histamine

• Primary source: - Mast cells • Mast cell degranulation: - Physical injury - Antibody binding - Anaphylotoxins (a complement peptides C3a, C4a, C5a) activation of CS)

Mast Cells

• Located in - Dermis - gut mucosa and submucosa - Conjunctiva - pulmonary alveoli and airways • Dermal mast cells are often located in close

proximity to blood vessels, nerves, and

lymphatics • Estimated density of 7000 to 20,000 mast cells

per cubic millimeter of skin

B. Serotonin

• Primary source: - Platelets - Neuroendocrine cells • Function: - Neurotransmitter in GIT

2. Arachadonic Acid Metabolites

• Types - Prostaglandins - Leukotrienes • Source - Membrane phospholipids • Stimuli - Mechanical, chemical, and physical stimuli or other mediators (e.g., C5a) release AA from membrane

phospholipids through the action of cellular phospholipases, mainly phospholipase.

3. Cytokines

• Proteins produced by cells • Chemokines: - Chemoattractant cytokines • Example: - TNF (Tumor necrosis factor) - IL-1

4. Complement system products

• plasma endopeptidases that comprise three interrelated systems, the kinin system that produces bradykinin, the complement system

that produces proteins that interact with antigen--antibody complexes and mediate

immunologic injury and inflammation, and the

clotting system that increases vascular permeability and chemotactic activity for the leukocytes.

Factor X is a clotting protein (also called a clotting factor). Clotting factors are specialized proteins that are essential for proper clotting, the process by which blood clumps together to plug the site of a wound to stop bleeding.

5. Coagulation products Clotting system

Kinin system

References

1. EI Hindawi, A.: Basic General Pathology. Faculty of Medicine, Cairo University 2009

2. Reid,R Callander, R Ramsden I, Roberts,F . MacFarlane,PS. Pathology Illustrated 6th

edition, Elsevier Science Health Science div 2005

3. Jones, E. & Morris, A. Cell biology & Genetics. Mosby, London Philadelphia SI Louis,

4. Sydney, Tokyo. 1998

5. Kumar,v., Abbas A.K. Cotran, R.S. Robbins,& Cotran Basic Pathology. 7" edition, W.B.

6. Saunders Co., Philadelphia, London, Toronto, Sydney, New York, Sydney & Tokyo.

2005

7. Stevens,J. & Lowe,J.: Pathology. Mosby. 1998

8. Underwood, J.C.E.: General and Systematic Pathology. 3' edition. Churchill Livingstone.

Edinburgh, London, Madrid, Melbourne, New York & Tokyo. 2000