Wound Healing The Basic Principles
 
Wound healing Day 21 - 2yrs Remodelling Contracture Day 4 - 21 Proliferation Granulation Day 1 - 4 Inflammation Immediate ...
Haemostasis <ul><li>Sealing of damaged blood vessels </li></ul><ul><li>Vasoconstriction </li></ul><ul><li>Platelet –utilit...
Inflammatory  phase <ul><li>Characterised by “ rubor et tumor cum calore et dolore” – 4 days. </li></ul><ul><li>Polymorpho...
Proliferative phase (4 – 21 days) <ul><li>Involves proliferation, granulation and contraction </li></ul><ul><li>Framers bu...
Remodelling or Maturation phase <ul><li>Interior finishing  Ξ  Remodeling or Maturation -> ↑Tensile strength </li></ul><ul...
 
Platelets <ul><li>Vessel damage </li></ul><ul><ul><li>Platelet aggregation </li></ul></ul><ul><ul><li>Activation of coagul...
Neutrophils <ul><li>Adhesion </li></ul><ul><li>Diapedesis </li></ul><ul><li>Migration by chaemotaxis </li></ul><ul><li>Pha...
Monocytes <ul><li>Monocyte  MACROPHAGE </li></ul><ul><li>Phagocytose bacteria </li></ul><ul><li>Release of cytokines </li>...
Lymphocytes <ul><li>Helper T cells </li></ul><ul><li>Produce chaemotactic factors like </li></ul><ul><ul><li>IFN –r, IL – ...
Fibroblast <ul><li>Synthesize </li></ul><ul><ul><li>Collagen </li></ul></ul><ul><ul><li>Fibronectin </li></ul></ul><ul><ul...
Angiocytes <ul><ul><li>Proliferation of endothelial cells </li></ul></ul><ul><ul><li>Formation of capillary buds </li></ul...
Keratinocytes <ul><li>Migration Resurface the wound </li></ul><ul><li>Phagocytosis </li></ul><ul><li>Cytokine release </li...
Healing responses Haemostsis Inflammation Proliferation Immediate Day 1 - 4 Day 4 - 21 Platelets Neutrophils Macrophages L...
 
Matrix <ul><li>Formation of fibrin plug marks the first stage of tissue repair  </li></ul><ul><li>It serves as a provision...
Matrix  contd. <ul><li>Matrix is composed of  </li></ul><ul><ul><li>Fibrous protein </li></ul></ul><ul><ul><li>Polysacchar...
Matrix  contd. <ul><li>Fibrous protein has two parts </li></ul><ul><ul><li>Structural part formed by collagen & elastin </...
Fibronectin <ul><li>Linear glycoproteins with modular cell/matrix binding structure </li></ul><ul><li>This structure encou...
Collagen <ul><li>They are the most abundant proteins in mammals  </li></ul><ul><li>They are secreted by fibroblast </li></...
Collagen contd. <ul><li>During fibroblastic phase PDGF,TGF & EGF stimulate fibroblast </li></ul><ul><li>Initially type 3 i...
Matrix metalloproteases <ul><li>Comprise the core wound enzyme </li></ul><ul><li>Brings about wound remodelling by matrix ...
Factors affecting wound healing <ul><li>Local factors </li></ul><ul><li>Infection </li></ul><ul><li>Blood supply </li></ul...
Factors affecting wound healing <ul><li>Systemic factors: </li></ul><ul><li>Age </li></ul><ul><li>Nutrition </li></ul><ul>...
Systemic factors <ul><li>Steroids </li></ul><ul><li>Immune deficiency </li></ul><ul><li>Cytotoxic drugs </li></ul><ul><li>...
Nutrition & wound healing <ul><li>Glucose </li></ul><ul><li>ATP, source of cellular energy  </li></ul><ul><li>Diabetes imp...
<ul><li>Components of phospholipid and prostaglandins </li></ul><ul><li>Phospholipid Cell membrane synthesis </li></ul><ul...
Proteins <ul><li>Deficiency causes </li></ul><ul><ul><li>Impaired collagen deposition  </li></ul></ul><ul><ul><li>Decrease...
<ul><li>Glutamine  </li></ul><ul><ul><li>Most abundant amino acid  </li></ul></ul><ul><ul><li>Essential for lymphocyte pro...
Arginine <ul><li>Enhances collagen deposition  </li></ul><ul><li>Enhances wound breaking strength </li></ul><ul><li>Substr...
Vitamins <ul><li>Vitamin A </li></ul><ul><ul><li>Influence inflammatory response in wounds </li></ul></ul><ul><ul><li>Incr...
Vitamins <ul><li>Vitamin C deficiency </li></ul><ul><ul><li>Impaired collagen synthesis & cross linking </li></ul></ul><ul...
Vitamins <ul><li>Vitamin E </li></ul><ul><ul><li>Decreases excess scar formation </li></ul></ul><ul><ul><li>As an antioxid...
Micronutrients <ul><li>Magnesium </li></ul><ul><ul><li>Co-factor for protein synthesis  </li></ul></ul><ul><ul><li>Provide...
Iron <ul><li>For hydroxylation of Proline & Lysine  </li></ul><ul><li>Part of Oxygen transport system </li></ul><ul><li>De...
Diabetes Mellitus <ul><li>Fibroblast & endothelial cells adversely affected </li></ul><ul><li>Collagen deposition reduced ...
Tissue  ischemia <ul><li>Tissue oxygen pr  < 40mm hg </li></ul><ul><ul><li>Delayed wound repair </li></ul></ul><ul><li>Red...
Tissue  ischemia <ul><li>Tissue O 2  pressure < 30 mm hg </li></ul><ul><li>Reduced killing of bacteria by phagocytosis </l...
Wound  debridement <ul><li>Reduces effects of ischaemia on wound healing </li></ul><ul><li>Removes tissue laden with bacte...
Types of wound healing <ul><li>Primary </li></ul><ul><li>Delayed primay </li></ul><ul><li>Secondary intention </li></ul>
Ideal wound dressing  <ul><li>Mechanical & bacterial protection </li></ul><ul><li>Moist environment </li></ul><ul><li>Faci...
Ideal wound dressing – contd. <ul><li>Non toxic & non allergenic </li></ul><ul><li>Highly absorbable & sterile </li></ul><...
Occlusive wound dressing <ul><li>Non resorbable </li></ul><ul><li>Sterile or non sterile device </li></ul><ul><li>Covers t...
Advantages of occlusive dressings <ul><li>↓  dehydration and cell death </li></ul><ul><li>↑  angiogenesis </li></ul><ul><l...
Non biologic occlusive dressing <ul><li>Films & foams </li></ul><ul><li>Hydrocolloids </li></ul><ul><li>Alginates </li></u...
Biologic  Occlusive Dressing <ul><li>Allograft </li></ul><ul><li>Xenograft </li></ul><ul><li>Amnion </li></ul><ul><li>Skin...
Upcoming SlideShare
Loading in …5
×

Acromegaly 19.07.08

2,680 views

Published on

0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
2,680
On SlideShare
0
From Embeds
0
Number of Embeds
167
Actions
Shares
0
Downloads
175
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

Acromegaly 19.07.08

  1. 1. Wound Healing The Basic Principles
  2. 3. Wound healing Day 21 - 2yrs Remodelling Contracture Day 4 - 21 Proliferation Granulation Day 1 - 4 Inflammation Immediate Haemostasis Days post injury Phase of healing
  3. 4. Haemostasis <ul><li>Sealing of damaged blood vessels </li></ul><ul><li>Vasoconstriction </li></ul><ul><li>Platelet –utility worker </li></ul><ul><li>Under the influence of the ADP, platelets aggregate and adhere to the exposed collagen. Intrinsic clotting cascade -> thrombin -> fibrinogen ->fibrin -> platelet aggregate into a stable haemostatic plug </li></ul>
  4. 5. Inflammatory phase <ul><li>Characterised by “ rubor et tumor cum calore et dolore” – 4 days. </li></ul><ul><li>Polymorphonuclear leukocytes - non skilled laborers – phagocytize debri and microorganisms, aided by local mast cells. </li></ul><ul><li>Macrophages – contractor – phagocytize bacteria –second line of defence and secrete IMs and growth factors like FGF,EGF,TGF beta, IL-1 which appears to direct the next stage. </li></ul>
  5. 6. Proliferative phase (4 – 21 days) <ul><li>Involves proliferation, granulation and contraction </li></ul><ul><li>Framers build the framework of the new house – “framer” cells – fibroblasts secrete collagen network – specialised fibroblasts -> wound contraction </li></ul><ul><li>The “plumber” cells , pericytes and endothelial cells -> angiogenesis </li></ul><ul><li>The “roofer” and “sider”cells - keratinocytes -> epithelisation </li></ul>
  6. 7. Remodelling or Maturation phase <ul><li>Interior finishing Ξ Remodeling or Maturation -> ↑Tensile strength </li></ul><ul><li>The cell -> fibroblast </li></ul><ul><li>Results in scar – active dynamic tissue </li></ul><ul><li>Stage I (upto 4 wks) – soft, fine&weak </li></ul><ul><li>Stage II (4 – 12 wks)–red, hard & strong </li></ul><ul><li>Stage III (12wks to 2 yrs) – soft, white& supple scar </li></ul>
  7. 9. Platelets <ul><li>Vessel damage </li></ul><ul><ul><li>Platelet aggregation </li></ul></ul><ul><ul><li>Activation of coagulation cascade </li></ul></ul><ul><ul><li>Clot </li></ul></ul><ul><ul><li>Degranulation Inflammatory mediators </li></ul></ul>
  8. 10. Neutrophils <ul><li>Adhesion </li></ul><ul><li>Diapedesis </li></ul><ul><li>Migration by chaemotaxis </li></ul><ul><li>Phagocytose bacteria </li></ul><ul><li>Scavenge necrotic debris and foreign material </li></ul>
  9. 11. Monocytes <ul><li>Monocyte MACROPHAGE </li></ul><ul><li>Phagocytose bacteria </li></ul><ul><li>Release of cytokines </li></ul><ul><li>Degradation of connective tissue </li></ul><ul><li>Stimulate angiogenesis </li></ul><ul><li>Inflammatory phase Reparative phase </li></ul>
  10. 12. Lymphocytes <ul><li>Helper T cells </li></ul><ul><li>Produce chaemotactic factors like </li></ul><ul><ul><li>IFN –r, IL – 2, CSF </li></ul></ul><ul><li>Involved in chronic wound healing </li></ul>
  11. 13. Fibroblast <ul><li>Synthesize </li></ul><ul><ul><li>Collagen </li></ul></ul><ul><ul><li>Fibronectin </li></ul></ul><ul><ul><li>Protein </li></ul></ul><ul><li>Fibroblast Myofibroblast Contraction </li></ul>Extracellular matrix
  12. 14. Angiocytes <ul><ul><li>Proliferation of endothelial cells </li></ul></ul><ul><ul><li>Formation of capillary buds </li></ul></ul><ul><ul><li>Angiogenesis </li></ul></ul>
  13. 15. Keratinocytes <ul><li>Migration Resurface the wound </li></ul><ul><li>Phagocytosis </li></ul><ul><li>Cytokine release </li></ul><ul><li>Reconstitution of basement membrane </li></ul><ul><li>Collagen secretion Anchoring fibrils </li></ul>
  14. 16. Healing responses Haemostsis Inflammation Proliferation Immediate Day 1 - 4 Day 4 - 21 Platelets Neutrophils Macrophages Lymphocyte Fibroblast Framers Contracture Angiocyte Plumber Keratinocytes Roofers & siders Utility worker Unskilled workers Contractor Asst. Contractor Remodeling Day 21–2 yrs Fibrocytes Remodelers
  15. 18. Matrix <ul><li>Formation of fibrin plug marks the first stage of tissue repair </li></ul><ul><li>It serves as a provisional matrix </li></ul><ul><li>Provisional matrix replaced by mature matrix during proliferative phase </li></ul>
  16. 19. Matrix contd. <ul><li>Matrix is composed of </li></ul><ul><ul><li>Fibrous protein </li></ul></ul><ul><ul><li>Polysaccharide gel </li></ul></ul><ul><ul><ul><li>Proteoglycans </li></ul></ul></ul><ul><ul><ul><li>Function </li></ul></ul></ul><ul><ul><ul><ul><li>Permits difussion of nutrients to the cells </li></ul></ul></ul></ul>
  17. 20. Matrix contd. <ul><li>Fibrous protein has two parts </li></ul><ul><ul><li>Structural part formed by collagen & elastin </li></ul></ul><ul><ul><li>Adhesive part formed by fibronectin and laminin </li></ul></ul>
  18. 21. Fibronectin <ul><li>Linear glycoproteins with modular cell/matrix binding structure </li></ul><ul><li>This structure encourages cell to cell & cell to substrate interaction </li></ul><ul><li>Fibronectin and its degradation products are chemo attractant </li></ul>
  19. 22. Collagen <ul><li>They are the most abundant proteins in mammals </li></ul><ul><li>They are secreted by fibroblast </li></ul><ul><li>At least 13 types have been described </li></ul><ul><li>Type 1- 4 are most common </li></ul><ul><li>Rich in glycine and proline </li></ul>
  20. 23. Collagen contd. <ul><li>During fibroblastic phase PDGF,TGF & EGF stimulate fibroblast </li></ul><ul><li>Initially type 3 is secreted in higher conc: (as in embryo) </li></ul><ul><li>Collagen degradation by collagenase occurs concurrently with collagen synthesis </li></ul>
  21. 24. Matrix metalloproteases <ul><li>Comprise the core wound enzyme </li></ul><ul><li>Brings about wound remodelling by matrix degradation </li></ul><ul><li>Produced by fibroblast </li></ul><ul><li>Regulated by cytokines </li></ul><ul><li>Increased level is seen in chronic wounds </li></ul>
  22. 25. Factors affecting wound healing <ul><li>Local factors </li></ul><ul><li>Infection </li></ul><ul><li>Blood supply </li></ul><ul><li>Foreign body </li></ul><ul><li>Tissue characteristics </li></ul><ul><li>Epithelium heals well </li></ul><ul><li>Nerve cells, cardiac muscle once </li></ul><ul><li>injured,do not heal </li></ul>
  23. 26. Factors affecting wound healing <ul><li>Systemic factors: </li></ul><ul><li>Age </li></ul><ul><li>Nutrition </li></ul><ul><li>Haematologic disturbance </li></ul><ul><li>Diabetes </li></ul><ul><li>Renal failure </li></ul><ul><li>Jaundice </li></ul><ul><li>Malignancy </li></ul>
  24. 27. Systemic factors <ul><li>Steroids </li></ul><ul><li>Immune deficiency </li></ul><ul><li>Cytotoxic drugs </li></ul><ul><li>Whole body irradiation </li></ul>
  25. 28. Nutrition & wound healing <ul><li>Glucose </li></ul><ul><li>ATP, source of cellular energy </li></ul><ul><li>Diabetes impairs wound healing </li></ul><ul><li>Inhibits </li></ul><ul><ul><li>Fibroblast </li></ul></ul><ul><ul><li>Endothelial cells </li></ul></ul><ul><ul><li>Leucocyte chaemotaxis </li></ul></ul>
  26. 29. <ul><li>Components of phospholipid and prostaglandins </li></ul><ul><li>Phospholipid Cell membrane synthesis </li></ul><ul><li>Prostaglandins Important in inflammation </li></ul><ul><li>Deficiency of free fatty acids causes impaired wound healing </li></ul>Fats
  27. 30. Proteins <ul><li>Deficiency causes </li></ul><ul><ul><li>Impaired collagen deposition </li></ul></ul><ul><ul><li>Decreased wound breaking strength </li></ul></ul><ul><ul><li>Increased wound infection rates </li></ul></ul><ul><ul><li>Decreased angiogenesis </li></ul></ul><ul><ul><li>Decreased cellular replication </li></ul></ul>
  28. 31. <ul><li>Glutamine </li></ul><ul><ul><li>Most abundant amino acid </li></ul></ul><ul><ul><li>Essential for lymphocyte proliferation </li></ul></ul><ul><ul><li>Stimulates immune response </li></ul></ul><ul><ul><li>Precursor for synthesis of nucleotides in fibroblasts & macrophages </li></ul></ul>Amino acids
  29. 32. Arginine <ul><li>Enhances collagen deposition </li></ul><ul><li>Enhances wound breaking strength </li></ul><ul><li>Substrate for nitric oxide synthesis </li></ul><ul><li>NO important in wound healing </li></ul>
  30. 33. Vitamins <ul><li>Vitamin A </li></ul><ul><ul><li>Influence inflammatory response in wounds </li></ul></ul><ul><ul><li>Increase macrophage influx </li></ul></ul><ul><ul><li>Stimulates collagen synthesis, cross linking </li></ul></ul><ul><ul><li>Stimulates epithelialisation </li></ul></ul>
  31. 34. Vitamins <ul><li>Vitamin C deficiency </li></ul><ul><ul><li>Impaired collagen synthesis & cross linking </li></ul></ul><ul><ul><li>Decreased angiogenesis </li></ul></ul><ul><ul><li>Haemorrhage </li></ul></ul><ul><ul><li>Susceptibility to infection </li></ul></ul>
  32. 35. Vitamins <ul><li>Vitamin E </li></ul><ul><ul><li>Decreases excess scar formation </li></ul></ul><ul><ul><li>As an antioxidant </li></ul></ul>
  33. 36. Micronutrients <ul><li>Magnesium </li></ul><ul><ul><li>Co-factor for protein synthesis </li></ul></ul><ul><ul><li>Provide structural stability to ATP & collagen synthesis </li></ul></ul><ul><li>Zinc </li></ul><ul><ul><li>Important in immune function </li></ul></ul><ul><ul><li>Deficiency causes wound infection </li></ul></ul>
  34. 37. Iron <ul><li>For hydroxylation of Proline & Lysine </li></ul><ul><li>Part of Oxygen transport system </li></ul><ul><li>Deficiency </li></ul><ul><ul><li>Impaired collagen production </li></ul></ul>
  35. 38. Diabetes Mellitus <ul><li>Fibroblast & endothelial cells adversely affected </li></ul><ul><li>Collagen deposition reduced </li></ul><ul><li>Wound Remodelling reduced </li></ul><ul><li>Chaemotaxis & phagocytosis reduced </li></ul><ul><li>Renal failure-> adverse effect </li></ul>
  36. 39. Tissue ischemia <ul><li>Tissue oxygen pr < 40mm hg </li></ul><ul><ul><li>Delayed wound repair </li></ul></ul><ul><li>Reduced collagen formation </li></ul><ul><li>Reduced cross linking </li></ul>
  37. 40. Tissue ischemia <ul><li>Tissue O 2 pressure < 30 mm hg </li></ul><ul><li>Reduced killing of bacteria by phagocytosis </li></ul><ul><li>Inhibition of angiogenesis </li></ul><ul><li>Inhibition of epithelialisation </li></ul>
  38. 41. Wound debridement <ul><li>Reduces effects of ischaemia on wound healing </li></ul><ul><li>Removes tissue laden with bacteria </li></ul>
  39. 42. Types of wound healing <ul><li>Primary </li></ul><ul><li>Delayed primay </li></ul><ul><li>Secondary intention </li></ul>
  40. 43. Ideal wound dressing <ul><li>Mechanical & bacterial protection </li></ul><ul><li>Moist environment </li></ul><ul><li>Facilitate epithelialisation </li></ul><ul><li>Allow gas & fluid exchange </li></ul><ul><li>Remain non adherent </li></ul>
  41. 44. Ideal wound dressing – contd. <ul><li>Non toxic & non allergenic </li></ul><ul><li>Highly absorbable & sterile </li></ul><ul><li>Easy to use </li></ul><ul><li>Suitable forms & sizes should be available </li></ul><ul><li>Aesthetically attractive </li></ul><ul><li>Cost effective </li></ul>
  42. 45. Occlusive wound dressing <ul><li>Non resorbable </li></ul><ul><li>Sterile or non sterile device </li></ul><ul><li>Covers the wound </li></ul><ul><li>Moist environment </li></ul><ul><li>Allow gas & fluid exchange </li></ul>
  43. 46. Advantages of occlusive dressings <ul><li>↓ dehydration and cell death </li></ul><ul><li>↑ angiogenesis </li></ul><ul><li>Enhanced autolytic debridement </li></ul><ul><li>↑ re – epithelisation </li></ul><ul><li>Bacterial barrier and ↓infection rates </li></ul><ul><li>↓ Pain </li></ul><ul><li>↓ Costs </li></ul>
  44. 47. Non biologic occlusive dressing <ul><li>Films & foams </li></ul><ul><li>Hydrocolloids </li></ul><ul><li>Alginates </li></ul><ul><li>Hydrogels </li></ul><ul><li>Silicon gel coats </li></ul><ul><li>Octylcyano acrylate </li></ul>
  45. 48. Biologic Occlusive Dressing <ul><li>Allograft </li></ul><ul><li>Xenograft </li></ul><ul><li>Amnion </li></ul><ul><li>Skin substitutes </li></ul>

×