Inflammation with chemical mediators and Recent Advances.pptx

Inflammation with chemical mediators and Recent Advances. This PPT also explain how Inflammation resolves and what are pericytes.

1. INFLAMMATION Dr. Madhan Prabhu

2. Introduction Inflammation is defined as the local response of living mammalian tissues to injury from any agent. It is a body defense reaction in order to eliminate or limit the spread of injurious agent, followed by removal of the necrosed cells and tissues. A protective mechanism

3. Inflammatory agents Infective agents - bacteria, viruses and their toxins, fungi, parasites. Immunological agents - cell-mediated and antigen- antibody reactions. Physical agents - heat, cold, radiation, mechanical trauma. Chemical agents - organic and inorganic poisons. Inert materials - such as foreign bodies.

4. Cardinal Signs 4 signs Aulus Cornelius Celsus Rubor Tumor Calor Dolor 5th sign is Functio Laesa - Rudolf Ludwig Carl Virchow

5. Classification Acute Short Duration Represents early body reaction - followed by healing Chronic Longer duration Causative agents acute inflammation persists for a long time Chronic Active Inflammation Stimulus is such that it induces chronic inflammation from the beginning

6. Acute Inflammation Main features Accumulation of fluid and plasma in the affected site Intravascular activation of platelets PMN Neutrophils as inflammatory cells 2 types Vascular Cellular

7. Acute Inflammation Vascular Events Haemodynamic changes Altered Vascular permeability

8. Acute Inflammation Vascular Events - Haemodynamic Changes Transient Vasoconstriction - immediate and irrespective, mainly in arterioles mild - 3 to 5 seconds, Severe - 5 mins Persistent continuous Vasodilation - mainly arterioles and lesser extent in others components, obvious in half and hour, increases blood to the microvascular bed - redness and warmth Local Hydrostatic Pressure - increased local hydrostatic pressure - transudate of fluid - swelling Slowing or Stasis - increased concentration of red cells - raised blood viscosity Leucocytic Margination - peripheral orientation of leucocyte along the vascular endothelium Stick to vascular endothelium Move and migrate through the gaps between the endothelium Known as Emigration

9. Acute Inflammation Vascular Events - Altered Vascular Permeability Accumulation of Oedema - fluid in interstitial compartment Escape of fluid is due to vasodilation and consequent elevation in hydrostatic pressure - Transudate Oedema appears by increased vascular permeability - Exudate

10. Mechanism in Increased Vascular Permeability Contraction of endothelial cells Retraction of endothelial cells Direct injury to endothelial cells Endothelial injury mediated by leucocytes Leakiness and Neo-vascularisation

11. Mechanism in Vascular Permeability Contraction of endothelial Cells Affects venules exclusively Endothelial cells develop temporary gaps Mediated by the release of Histamine, Bradykinin and other chemical Mediators Short duration (15 - 30 mins) - immediately after injury

12. Mechanism in Vascular Permeability Retraction of endothelial cells Structural reorganisation of cytoskeleton of endothelial cells, reversible retraction of at the intercellular junctions. Mediated by cytokines IL-1, TNF alpha

13. Mechanism in Vascular Permeability Direct Injury to endothelial cells Causes cell necrosis and appearance of physical gaps. Process of thrombosis is initiated at the site of damaged endothelial cells. Affects all levels of micro vasculature. Either appear immediately after injury and last for several hours or days - severe bacterial infections Or delay of 2-12 hours and last for hours or days - moderate thermal injury and radiation injury

14. Mechanism in Vascular Permeability Endothelial injury mediated by Leucocytes Adherence of leucocytes to the endothelium at the site of inflammation. Activation of leucocytes - release proteolytic enzymes and toxic oxygen. Cause endothelial injury and increased vascular leakiness. Affects mostly venules and is a late response.

15. Mechanism in Vascular Permeability Leakiness and Neovascularisation Newly formed capillaries under the influence of vascular endothelial growth factor (VEGF). Process of repair and in tumours are excessively leaky

16. Cellular Events Cellular phase of inflammation consists of 2 processes Exudation of Leucocyte Phagocytosis

17. Cellular Events Exudation of Leucocyte Changes in the formed elements of blood Rolling and adhesion Emigration Chemotaxis

18. Cellular Events Exudation of Leucocyte - Changes in the formed elements of blood Central stream of cells comprised by leucocytes and RBCs and peripheral cell free layer of plasma close to vessel wall. Later, central stream of cells widens and peripheral plasma zone becomes narrower because of loss of plasma by exudation. This phenomenon is known as margination. Neutrophils of the central column come close to the vessel wall - pavementing

19. Cellular Events Exudation of Leucocyte - Rolling and Adhesion Peripherally marginated and pavemented neutrophils slowly roll over the endothelial cells lining the vessel wall (rolling phase). Transient bond between the leucocytes and endothelial cells becoming firmer (adhesion phase). The following molecules bring about rolling and adhesion phases Selectins Integrins Immunoglobulin gene superfamily adhesion molecule

20. Cellular Events Exudation of Leucocyte - Exudation After sticking of neutrophils to endothelium, They move along the endothelial surface till a suitable site between the endothelial cells is found where the neutrophils throw out cytoplasmic pseudopods. Cross the basement membrane by damaging it locally - collagenases and escape out into the extravascular space - emigration Diapedesis - escape of red cells through gaps between the endothelial cells Passive phenomenon Raised hydrostatic pressure Hemorrhagic appearance to the inflammatory exudate

21. Cellular Events Exudation of Leucocyte - Chemotaxis After extravasating from the blood, Leukocytes migrate toward sites of infection or injury along a chemical gradient by a process called chemotaxis They have to cross several barriers - endothelium, basement membrane, perivascular myofibroblasts and matrix. Potent chemotactic substances or chemokines for neutrophils. Leukotriene B4 (LT-B4) - arachidonic acid metabolites. Components of complement system - C5a and C3a in particular. Cytokines Interleukins, in particular IL-8

22. Cellular Events Exudation of Leucocyte - Chemotaxis

23. Cellular Events Phagocytosis The process of engulfment of solid particulate material by the cells. 2 main types of phagocytic cells Polymorphonuclear neutrophils (PMNs) : early in acute inflammatory response, also known as microphages Macrophages: Circulating monocytes and fixed tissue mononuclear phagocytes This phagocytic cells releases proteolytic enzymes lysozyme, protease, collagenase, elastase, lipase, proteinase, gelatinase and acid hydrolases

24. Cellular Events Phagocytosis The microbe undergoes the process of phagocytosis in following 3 steps : Recognition and attachment Engulfment Killing and degradation

25. Cellular Events Phagocytosis - Recognition and attachment Phagocytosis is initiated by the expression of surface receptors on macrophages. Its further enhanced when the microorganisms are coated with specific proteins, opsonins. Establish a bond between bacteria and the cell membrane of phagocytic cell. Major opsonins are lgG opsonin. C3b opsonin Lectins

26. Cellular Events Phagocytosis - Engulfment Formation of cytoplasmic pseudopods around the particle due to activation of actin filaments around cell wall. Eventually plasma membrane gets lysed and fuses with nearby lysosomes - phagolysosome.

27. Cellular Events Phagocytosis - Killing and Degradation Killing of Microorganism take place by Antibacterial substances further degraded by hydrolytic enzymes Sometimes this process fails to kill and degrade some bacteria like tubercle bacilli.

28. Cellular Events Phagocytosis

29. Cellular Events Disposal of Microorganism Intracellular mechanisms Oxidative bactericidal mechanism by oxygen free radicals MPO-dependent MPO-independent Oxidative bactericidal mechanism by lysosomal granules Non-oxidative bactericidal mechanism Extracellular mechanisms Granules Immune mechanisms

30. Cellular Events Disposal of Microorganism - Intracellular mechanisms Kill microbes more often by oxidative mechanism and less often non-oxidative pathways Oxidative bactericidal mechanism by oxygen free radicals. Production of reactive oxygen metabolites (0' 2 H 2 2 , OH', HOCI, HOI, HOBr) Activated phagocytic leucocytes requires the essential presence of NADPH oxidase Present in the cell membrane of phagosome reduces oxygen to superoxide ion (0’ 2 )

31. Cellular Events Disposal of Microorganism - Intracellular mechanisms Superoxide is subsequently converted into H202 Bactericidal activity is carried out either via enzyme MPO dependent or MPO independent. MPO dependent killings MPO acts on H2O2, in the presence of halides - form hypochlorous acid (HOCI, HOI, HOBr) MPO independent killings Mature macrophages lack the enzyme MPO. bactericidal activity by producing OH- ions and superoxide singlet oxygen (0’) H2O2, in the presence of 0'2 (Haber - Weiss reaction) or in the presence of Fe++ (Fenton reaction)

32. Cellular Events Disposal of Microorganism - Intracellular mechanisms Oxidative bactericidal mechanism by lysosomal granules preformed granule-stored products of neutrophils and macrophages. secreted into the phagosome and the extracellular environment. Non-oxidative bactericidal mechanism Some agents released from the granules of phagocytic cells do not require oxygen for bactericidal activity Granules: cause lysis within phagosome, ex: lysosomal hydrolases, permeability increasing factors, cationic proteins (defensins), lipases, ptoteases, DNAases. Nitric oxide: reactive free radicals similar to oxygen free radicals potent mechanism of microbial killing produced by endothelial cells as well as by activated macrophages

33. Cellular Events Disposal of Microorganism - Extracellular mechanisms Granules Degranulation by macrophages and neutrophils same as intercellular Immune mechanisms immune-mediated lysis of microbes takes place outside the cells by mechanisms of cytolysis, antibody-mediated lysis and by cell-mediated cytotoxicity

34. Outcomes of Acute Inflammation Resolution - restoration to normal, limited injury chemical substances neutralisation normalisation of vascular permeability apoptosis of inflammatory cells lymphatic drainage Healing by scar tissue destruction fibrinous inflammation purulent inflammation -› abscess formation (pus, pyogenic membrane, resorption - pseudoxanthoma cells - weeks to months) Progression into chronic inflammation

35. Chemical Mediators of Inflammation Chemical mediators that are responsible for vascular and cellular events Knowledge of this mediators - basis of anti-inflammatory drugs. It may be either of two types, Cell Derived - produced locally by cells at the site of inflammation Plasma derived - mainly from liver Some mediators are derived from Necrotic cells

36. Chemical Mediators of Inflammation Induce their effects by binding to specific receptors on target cells - it may be one or a very few targets, or multiple Some may have direct enzymatic and/or toxic activities. Ex: lysosomal proteases Some may stimulate target cells to release secondary effector molecules Control the response and tightly regulated Amplify a particular response Opposing effects Once activated and released from the cell, mediators either Quickly decay. Ex: arachidonic acid metabolites Inactivated by enzymes ex: kininase inactivates bradykinin Eliminated Ex: antioxidants scavenge toxic oxygen metabolites Inhibited. Complement-inhibitory proteins

37. Chemical Mediators of Inflammation Sequestered in intracellular granules Rapidly secreted upon cellular activation. Ex: histamine in mast cells Synthesised from beginning in response to a stimulus. Ex: Prostaglandins and cytokines Tissue macrophages, mast cells, and endothelial cells - capable of producing different mediators. Various cell derived mediators Vasoactive amines Arachidonic acid metabolites Lysosomal component Platelet activating factors (PAF) Cytokines Reactive Oxygen Species (ROS) and nitrogen oxide (NO) Neuropeptides

38. Chemical Mediators of Inflammation Cell derived Mediators - Vasoactive Amines Stored as preformed molecules in mast cells or early inflammatory cells. Histamine many cell types, particularly mast cells adjacent to vessels, circulating basophils and platelets variety of stimuli physical injury immune reactions involving binding of IgE antibodies to Fc receptors on mast cells C3a and C5a fragments of complement - anaphylatoxins Leukocyte-derived histamine-releasing proteins Neuropeptides e.g., substance P Certain cytokines e.g., IL-1 and IL-8 arteriolar dilation & increased vascular permeability : endothelial contraction and interendothelial gaps itching and pain inactivated by Histaminase

39. Chemical Mediators of Inflammation Cell derived Mediators - Vasoactive Amines Serotonin 5-hydroxytryptamine preformed vasoactive mediator - effects similar to those of histamine but less potent Released from platelet dense body granules during platelet aggregation

40. Chemical Mediators of Inflammation Cell derived Mediators - Arachidonic acid Metabolites Also known as eicosanoids. Variety of biologic processes, including inflammation and hemostasis - virtually every step of inflammation. short-range hormones that act locally at the site of generation and then decay spontaneously or are enzymatically destroyed Derived from : Leukocytes, mast cells, endothelial cells, and platelets Dietary linoleic acid

41. Chemical Mediators of Inflammation Cell derived Mediators - Arachidonic acid Metabolites Component of cell membrane phospholipids. AA is released from these phospholipids via cellular phospholipase that have been activated by mechanical, chemical, or physical stimuli, or by inflammatory mediators such as C5a. Metabolism proceeds along either of this two major enzymatic pathways Cyclooxygenase: prostaglandins and thromboxanes - AUTOCOIDS Lipoxygenase: leukotrienes and lipoxins

42. Chemical Mediators of Inflammation Cell derived Mediators - Arachidonic acid Metabolites Cyclooxygenase - a fatty acid enzyme present as COX-1 and COX-2, Metabolises AA to following derivative Prostaglandins (PGD2, PGE2 and PGF2-0) Thromboxane A2 (TXA2) Prostacyclin (PG12) Resolvins Major anti-inflammatory drugs act by inhibiting activity of the enzyme COX - inhibitors (NSAIDs)

43. Chemical Mediators of Inflammation Cell derived Mediators - Lipo-oxygenase Pathway Lipo-oxygenase - predominant enzyme in neutrophils. Acts on activated AA to form hydroperoxy eicosatetraenoic acid (5-HPETE). Further per-oxidation forms following metabolites 5-HETE (hydroxy compound) - intermediate Leukotrienes (LT) Lipoxins (LX)

44. Chemical Mediators of Inflammation Cell derived Mediators - Pathways

45. Chemical Mediators of Inflammation Cell derived Mediators - Lysosomal Components Inflammatory cells like neutrophils and monocytes - lysosomal granules. Its of 2 types : Granules of neutrophils Primary or azurophil: myeloperoxidase, acid hydrolases, acid phosphatase, lysozyme, defensins (cationic protein), phospholipase, cathepsin G, elastase, and protease Secondary or specific: alkaline phosphatase, lactoferrin, gelatinase, collagenase, lysozyme, vitamin-B12 binding proteins, plasminogen activator Tertiary: gelatinase and acid hydrolases Granules of monocytes and tissue macrophages acid proteases, collagenase, elastase and plasminogen activator more active in chronic inflammation

46. Chemical Mediators of Inflammation Cell derived Mediators - Platelet activating factors Phospholipid (membrane) -derived mediator with a broad spectrum of inflammatory effects. Membrane of neutrophils, monocytes, basophils, endothelial cells, and platelets (and other cells) by the action of phospholipase Az. Functions of PAF Stimulating platelets, vasoconstriction and bronchoconstriction inducing vasodilation and increased vascular permeability low conc. 100-1000 times potent than HISTAMINE enhanced leukocyte adhesion, chemotaxis, leukocyte degranulation, and the oxidative burst stimulates the synthesis of other mediators, particularly eicosanoids

47. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines polypeptide substances produced by activated lymphocytes (lymphokines) and activated monocytes (monokines). Major cytokines in acute inflammation TNF and IL-1, Chemokines - a group of chemoattractant cytokines Chronic inflammation : interferon- (IFN-𝜸) and IL-12

48. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines - Tumor necrosis factor and Interleukin 1 Produced by activated macrophages, as well as mast cells, endothelial cells, and some other cell types Stimulated by microbial products, such as bacterial endotoxin, immune complexes, and products of T lymphocytes Principal role in inflammation - endothelial activation expression of adhesion molecules on endothelial cells - increased leukocyte binding and recruitment, enhance the production of additional cytokines (notably chemokines) and eicosanoids

49. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines - Tumor necrosis factor and Interleukin 1 TNF - increases thrombogenicity of endothelium and causes aggregation and activation of neutrophils IL-1 - fibroblasts, resulting in increased proliferation and production of extracellular matrix May enter the circulation - systemic acute-phase reaction Fever & lethargy hepatic synthesis of various acute-phase proteins, metabolic wasting (cachexia), neutrophil release into the circulation, release of adrenocorticotropic hormone (inducing corticosteroid synthesis and release).

50. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines - Tumor necrosis factor and Interleukin 1

51. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines - Chemokines act primarily as chemoattractants for different subsets of leukocytes Also activate leukocytes Chemokines are classified into four groups out of which 2 are the major group CXC chemokines: IL-8 CC chemokines : MCP-1

52. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines - Reactive Oxygen Species synthesized via the NADPH oxidase - from neutrophils and macrophages by microbes, immune complexes, cytokines, and a variety of other inflammatory stimuli Within lysosomes - destroy phagocytosed microbes and necrotic cells low levels increase chemokine, cytokine, and adhesion molecule expression amplifying the cascade of inflammatory mediators

53. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines - Reactive Oxygen Species High levels - tissue injury by several mechanisms endothelial damage, with thrombosis and increased permeability; protease activation and anti-protease inactivation, with a net increase in breakdown of the ECM; direct injury to other cell types Various antioxidant - protective mechanisms against this ROS catalase, superoxide dismutase, and glutathione

54. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines - Nitric Oxide short-lived, soluble, free-radical gas formed by activated macrophages during the oxidation of arginine by the action of enzyme, NO synthase (NOS). Three isoforms of NOS Type I (nNOS) - neuronal, no role in i/m Type II (iNOS) - induced by chemical mediators, macrophages and endothelial cells Type III (eNOS) - primarily (but not exclusively) within endothelium

55. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines - Nitric Oxide NO plays many roles in inflammation including relaxation of vascular smooth muscle (vasodilation), antagonism of all stages of platelet activation (adhesion, aggregation, and degranulation) reduction of leukocyte recruitment at inflammatory sites action as a microbicidal (cytotoxic) agent (with or without superoxide radicals) in activated macrophages.

56. Chemical Mediators of Inflammation Cell derived Mediators - Cytokines - Neuropeptides initiate inflammatory responses small proteins, such as substance P transmit pain signals, regulate vessel tone, and modulate vascular permeability prominent in the lung and gastrointestinal tract

57. Chemical Mediators of Inflammation Plasma Protein Derived Mediators Circulating proteins of four interrelated systems - the complement, kinin, clotting and fibrinolytic systems Inactive precursors that are activated at the site of inflammation - action of enzyme. Each of these systems has its inhibitors and accelerators in plasma - negative and positive feedback mechanisms respectively. Hageman factor (factor XII) of clotting system - a key role in interactions of the four systems.

58. Chemical Mediators of Inflammation Hageman Factor protein synthesized by the liver. initiates four systems involved in the inflammatory response Kinin system - vasoactive kinins; Clotting system - inducing the activation of thrombin, fibrinopeptides, and factor X, Fibrinolytic system - plasmin and inactivating thrombin; Complement system - anaphylatoxins C3a and C5a Gets activated - collagen, basement membrane, or activated platelets.

59. Chemical Mediators of Inflammation Hageman Factor

60. Chemical Mediators of Inflammation Clotting System Factor XIla - driven proteolytic cascade leads to activation of thrombin. Functions of thrombin cleaves circulating soluble fibrinogen to generate an insoluble fibrin clot Fibrinopeptides - increase vascular permeability & chemotactic for leukocytes. In inflammation, Binding of thrombin to the receptors on endothelial cells - activation and enhanced leukocyte adhesion

61. Chemical Mediators of Inflammation Clotting System

62. Chemical Mediators of Inflammation Fibrinolytic System Hageman factor induces clotting system and fibrinolytic system concurrently - control over the 2 system Limit clotting by cleaving fibrin - solubilising the fibrin clot. In absence of this - even minor injury could lead to coagulation of entire vasculature. Plasminogen activator - released from endothelium, leukocytes, and other tissues and kallikrein from kinin system Cleave plasminogen, a plasma protein - further forms PLASMIN

63. Chemical Mediators of Inflammation Fibrinolytic System

64. Chemical Mediators of Inflammation Kinin System Haegman Factor activates Prekallikrein activator - acts on plasma prekallikrein to give kallikrein. Kallikrein acts on kininogen (HMW) to give Bradykinin. Bradykinin are short-lived - rapidly degraded by kininases present in plasma and tissues

65. Chemical Mediators of Inflammation Kinin System Slow contraction of smooth muscle Bradykinin acts in the early stage of inflammation : vasodilatation; increased vascular permeability pain

66. Chemical Mediators of Inflammation Complement System Important role in host defense (immunity) and inflammation Consists of plasma proteins (C1 - C9) - activated at the sites of i/m Contribute to the inflammatory response by increasing vascular permeability and leukocyte chemotaxis. The activation of complement - tightly controlled by cell-associated and circulating regulatory proteins Inappropriate or excessive complement activation (e.g., in antibody-mediated diseases) - serious tissue injury in a variety of immunologic disorders

67. Chemical Mediators of Inflammation Complement System The critical step in the activation of biologically active complement products is the activation of the third component, C3 - C3a. This occurs in 3 steps : Classical Pathway : antigen-antibody complexes Alternative pathway: triggered by bacterial polysaccharides - microbial cell-wall components Lectin pathway : plasma lectin binds to mannose residues on microbes - activates early component of the classical pathway • As C3 activated - further activation of other complement proteins takes place i.e C1 - C9

68. Chemical Mediators of Inflammation Complement System The actions of activated complement system in inflammation are as under: C3a, C5a, C4a (anaphylatoxins) - activate mast cells and basophils to release of histamine C3b - an opsonin. C5a - chemotactic for leucocytes. Membrane attack complex (MAC) (C5b-C9) - a lipid dissolving agent and causes holes in the phospholipid membrane of the cell

69. Chemical Mediators of Inflammation Complement System

70. Chronic Inflammation Inflammation of prolonged duration (weeks to months to years) in which active inflammation, tissue injury, and healing proceed simultaneously. It involves mainly following events Angiogenesis Mononuclear cell infiltrate - macrophages, lymphocytes, and plasma cells Fibrosis - Scar

71. Chronic Inflammation Causes Following acute inflammation persistence of the injurious agent or because of interference with the normal process of healing e.g. in osteomyelitis, pneumonia terminating in lung abscess Recurrent attacks of acute inflammation repeated bouts of acute inflammation culminate in chronicity of the process Ex: Recurrent urinary tract infection - chronic pyelonephritis, Repeated acute infection of gall bladder - chronic cholecystitis Chronic inflammation starting from beginning low pathogenicity is chronic from the beginning Ex: infection with Mycobacterium tuberculosis, Treponema palladium

72. Chronic Inflammation Cells and Mediators Macrophages Lymphocytes, Plasma Cells, Eosinophils, Mast Cells

73. Chronic Inflammation Macrophages Dominant cells of chronic inflammation Derived from circulating blood monocytes Reticulo - endothelial system Also known as Mononuclear-phagocyte system. Macrophage present in liver - Kupffer cells spleen lymph nodes - sinus histiocytes central nervous system - microglial cells lungs - alveolar macrophages

74. Chronic Inflammation Lymphocytes T and B lymphocytes migrate - inflammatory sites - chemokines. Lymphocytes and macrophages interact in a bidirectional way important role in chronic inflammation

75. Chronic Inflammation Eosinophils inflammatory sites around parasitic infections or as part of immune reactions mediated by IgE Associated with allergies Induced by specific chemokines - eotaxin Granules contain major basic protein - highly charged cationic protein toxic to parasites also causes epithelial cell necrosis

76. Chronic Inflammation Mast Cells Sentinel (watch) cells widely distributed in connective tissues throughout the body Both acute and chronic inflammatory responses. Produced by cytokines such as TNF and chemokines atopic individuals - individuals prone to allergic reactions Mast cells Armed with IgE antibody As the environmental antigens enters It releases histamines and AA metabolites anaphylactic shock

77. Chronic Inflammation Systemic Effects Fever: infectious form of inflammation Anaemia: accompanied by anaemia of varying degree Leucocytosis : leucocytosis but generally there is relative lymphocytosis in these cases. ESR: elevated Amyloidosis: develop secondary systemic amyloidosis.

78. Chronic Inflammation Systemic Effects Also known as acute-phase reaction. Cytokines TNF, IL-1, and IL-6. The acute-phase response consists of several clinical and pathologic changes Fever Elevated plasma levels of acute-phase proteins C-reactive protein (CRP), Fibrinogen, Serum amyloid A (SAA) protein Leukocytosis septic shock

79. Chronic Inflammation Fever Especially when inflammation is caused by infection Pyrogens - Prostaglandin (PG) synthesis in the vascular and perivascular cells of the hypothalamus - NEUROTRANSMITTER- temp. reset. Lipopolysaccharide (LPS) from bacterial cell wall (Exogenous Pyrogens) - Leukocytes - cytokines like IL1 & TNF (Endogenous Pyrogens) - COX (AA-PG)

80. Chronic Inflammation

81. Pericytes Pericytes (previously known as Rouget cells) are multi-functional mural cells of the microcirculation that wrap around the endothelial cells. Embedded in the basement membrane of blood capillaries, where they communicate with endothelial cells by means of both direct physical contact and paracrine signalling

82. Pericytes Pericyte - mediated leukocyte diapedesis involves Crawling through the basement membrane Adhesion to and crawling on pericytes Finally migration through pericyte gaps into interstitial space Neutrophils first interact with adhesion molecules on the surface of pericytes

83. Pericytes Pericytes not only support leukocytes during diapedesis; They also potentiate leukocyte effector functions in the interstitial space. Pericyte gaps maintain the integrity of the basement membrane by forming preferential paths for leukocyte recruitment in addition to forming a barrier to excessive leukocyte extravasation

84. Pericytes

85. Resolution of Inflammation Once the toxins are removed the inflammatory process has to end, they are done by

86. Management NSAIDs Steroids Serratiopeptidase

87. Management NSAIDs They decrease inflammation and fever by inhibiting Cyclooxyrgenase pathway Some studies suggest that preoperative medication delayed pain onset, decreased peak pain intensity and postoperative swelling, thus reducing post operative amount of discomfort. COX 1 mainly produces prostaglandins, COX 2 solely responsible for production of Prostaglandin products (PGE2 and Prostacyclin)

88. Management NSAIDs Ketorolac 300 times more selective in blocking COX 1 than COX 2 is most ulcerogenic This explains why it is given for acute pain for no more than 5 days Celecoxib is 8 times more selective in inhibiting COX 2 - given for chronic pain and longer duration It has higher risk of causing MI and Stroke Acetaminophen is weak inhibitor of both COX, unlike Ibuprofen and diclofenac, it does not block the substrate binding channel of enzymes but disrupts electron transfer

89. Management NSAIDs It works more downstream than other NSAIDs in cyclooxygenase pathway This is the reason it is combined with other NSAIDs such as ibuprofen and Diclofenac which causes synergistic effect These drugs should be avoided in patient with aspirin, NSAID sensitive asthma because the blockade of COX can shift the archadonic pathway to bronchoconstrictive and pro-inflammatory lipoxygenase products Avoided in patient with true NSAID allergies, GI ulcers Oral anticoagulant patients because of its additive anti platelet effect And patients taking lithium as they inhibit active secretion of widely used bipolar depression drug

90. Management Steroids They act by suppression of each stage of inflammation They decrease capillary dilation - leukocyte migration - phagocytosis Decrease in total number of circulating lymphocytes, Basophils, eosinophils and monocytes Inhibition of formation of granulation tissue by retarding fibroblast proliferation and collagen synthesis Their major role is reducing the production of Phospholipase enzyme which is responsible for the COX/LOX pathways They inhibit the production of prostaglandin, leukotrienes as well as reducing chemoattractants such as Cytokines

91. Management Steroids - Common Preparation Plasma Half life for various synthetic glucocorticoids range from 1hr to 4hr Plasma half life is not a good indication of biological activity rather suppression of adrenocorticotropic hormone by pituitary gland after administration of single dose of glucocorticoid A dose must be equal or exceed the physiological amount released by the body Usually 15-25mg/day is released at time of crisis 300 mg is released, thus a dose exceeding this limit is recommended

92. Management Steroids - Common Preparation Post operative oedema peaks 48-72 hours after surgery, most glucocorticoids effect do not exceed 24hr To maintain anti inflammatory efficacy a minimum of 3 days to maximum of 5 days to maximise their benefit and minimise the risk of delayed wound healing HPA Axis suppression Ideal route is IV - immediate pharmacological response, reduce patient noncompliance, more predictable response Oral administration - delayed onset, can create erratic response, relies on patient compliance. However convenient, economic and safe

93. Management Steroids - Adverse Effects Osteoporosis, fracture and osteonecrosis - initially favouring osteoclastic active, reducing calcium absorption in gut. 5 mg or more prednisolone associated with bone loss and increased bone fracture Adrenal Suppression - occurs when exposure to exogenous corticosteroids. Inhaled and topical also induced, Sudden withdrawal - Gradual tapering Cushingoid Feature - Risk is higher in patients with higher Body mass index, younger and high caloric intake

94. Management Steroids - Adverse Effects Diabetic and Hyperglycaemia - Most common cause of drug induced DM, increased Insulin resistant DM. Effect shows higher post prandial than fasting Myopathy - Muscle weakness and atrophy higher doses - rapid onset. Decreased synthesis and catabolism of proteins Glaucoma and Cataracts - Painless increase in intraocular pressure,

95. Management Serratiopeptidase Reduces capillary permeability induced by histamine, bradykinin, and serotonin Breaks down abnormal exudates and proteins; facilitates the absorption of decomposed products through blood and lymphatics Enzyme promotes wound healing and repair and restores the skin temperature of the inflamed area, burn or trauma to normal Absorbed in gut -> Systemic Circulation. Once absorbed it penetrates in all tissues and attains higher concentration in inflamed tissues, peak in 1 hour Promotes wound healing and repair, restores the skin temperature of the inflamed area, burn or trauma to normal It does not bind with LOX and block LOX-catalysed Specialised Pro-Resolvin Mediators biosynthesis

96. Management Serratiopeptidase Recent studies Use of ciprofloxacin and serratiopeptidase periodontal solutions for extended drug delivery was studied Comparative study, the anti-inflammatory activity of serratiopeptidase with dexamethasone in the control of inflammation was demonstrated Serratiopeptidase along with broad spectrum antibiotics was employed in the treatment of osteoarticular infection Enzyme was also reported effective in the treatment of peri-implantitis in combination with several antibiotics

97. Newer Modalities Micro RNAs Bone Marrow derived Mesenchymal Stem Cells Medical Maggot Therapy Topical Insulin Fluorescence Biomodulation Hyperbaric Oxygen Therapy

98. Newer Modalities MicroRNAs Small noncoding RNA of 22 nucleotide long, regulates various cellular and physiological function Can regulate the process of inflammation by targeting mRNAs of mediators of inflammation Drawbacks - single micro RNA can silence number of different protein - specificity of treatment is a problem Overdose can cause non specific immune response and toxicity

99. Newer Modalities Bone Marrow derived Mesenchymal Stem Cells Strong potential for cutaneous wound healing Impart faster wound healing via higher cell migration, angiogenesis, epithelialisation and granulation tissue formation. They secrete chemoattractants macrophages and keratinocytes Drawbacks - Malignant transformation Spread of Infectious diseases

100. Newer Modalities Medical Maggot Therapy Disinfected maggots are used Cleans and disinfects wound by clearing necrotic tissue Secretion or Excretion reduced superoxide production and lowers the production of MPO from neutrophils Decreases pro-inflammatory cytokines and increased anti inflammatory cytokines Drawbacks - Pain and Discomfort

101. Newer Modalities Topical Insulin Peptide hormone with wide physiological function It has been found that insulin receptor are significantly expressed in damaged wound than intact skin indicating insulin signalling pathway in wound repair Anti inflammatory property due to IL - 4, IL - 13, IL 10 and lower IFN-𝜸 Inactivation of TNF-𝛂 mediated inflammatory pathway Topical application in diabetic foot ulcer showed faster healing than conventional topical gels

102. Newer Modalities Fluorescence Biomodulation Kind of laser using red or near infra red light for reducing inflammation and promoting wound healing Decreased TNF-𝛂 and up regulated VEGF and Mettaloprotineases Mechanism is by reducing microbial load, down regulation of pro inflammatory cytokines, induction of cell proliferation, stimulation angiogenesis, increased collagen production and minimal scar formation

103. Newer Modalities Hyperbaric Oxygen Therapy Oxygen impairment leads to hamper wound healing phase Activated immune cells, cytokine, Modulate inflammatory and bacterial mediators Reducing inflammation and regeneration macrophage and satellite cell activation Increasing levels of VEGF, IL-6 and down regulating endothelia - 1 In soft tissue and bone infection - reduced growth of microorganism thus improving leukocyte and macrophage function Drawback - Claustrophobia, reversible myopia, mild to severe pain to Barotrauma

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