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Home , Granulation tissue, Healing, Inflammation, Wound healing

• Dhaval Bhavsar, MD • Assistant Professor Dept of Plastic, Wound and KUMC

Dhaval Bhavsar, (Basics) Skin

• Largest • Provides

. Protection from elements, Infective organisms

. Protective sensation

• When breached – , loss of thermal regulation

Dhaval Bhavsar, Wound Healing (Basics) Normal Skin

http://www.agen.ufl.edu/~chyn/age2062/lect/lect_19/174.gif

Dhaval Bhavsar, Wound Healing (Basics)

http://www.ratbehavior.org/images/Epidermis.jpg

Dhaval Bhavsar, Wound Healing (Basics)

http://neuromedia.neurobio.ucla.edu/campbell/skin/wp_images/161_dermis.gif

Dhaval Bhavsar, Wound Healing (Basics) What is Wound

“any break in the skin or an organ caused by violence or surgical incision” http://www.udap.com/images/yellowstone

Dhaval Bhavsar, Wound Healing (Basics) Wound Healing

• restoration of continuity after wounding

http://fulton.edzone.net/cites/winkler-science/team1/chapter%205/image11.gif

Dhaval Bhavsar, Wound Healing (Basics) Wound Healing- 3 Classic Phases

• • Proliferation • Remodeling

http://www.bumc.bu.edu/www/Busm/sg/Images/suturing/phase2.gif

Dhaval Bhavsar, Wound Healing (Basics)

• Clot formation

• Start point of inflammation

Dhaval Bhavsar, Wound Healing (Basics) Inflammatory phase

• Starts within 6-8 hrs

• PMN cells

• Later ()

Dhaval Bhavsar, Wound Healing (Basics) Inflammation

• Reaches its height at 24-48 hrs

• Also release growth factors

• Prepares wound for proliferation

Dhaval Bhavsar, Wound Healing (Basics) Proliferation

• Fibroplasia

• Matrix deposition

•

• Re-epithelialization

Dhaval Bhavsar, Wound Healing (Basics) Granulation

http://www.worldwidewounds.com/2002/april/Vowden/images/WBP-Figure-5e.jpg http://medweb.bham.ac.uk/http/depts/path/Teaching

Dhaval Bhavsar, Wound Healing (Basics) Fibroplasia

• – activated • Most important cells • Secrete- • • • • •

Dhaval Bhavsar, Wound Healing (Basics) Fibroplasia

• Fibroblasts increase in number as inflammatory cells decrease

• Begins 3-5 days after wounding

• Migrate and proliferate in response to fibronectin, -derived (PDGF), growth factor, transforming growth factor, and C5a

Dhaval Bhavsar, Wound Healing (Basics) Collagen deposition

• The most important matrix component

• Deposition starts about 3rd day and continues for 2-4 weeks depending on wound size

• Procollagen Tropocollagen Collagen

Dhaval Bhavsar, Wound Healing (Basics) Collagen Deposition

• Collagen deposition dependent on

• Age • Tension • Pressure •

Dhaval Bhavsar, Wound Healing (Basics) Matrix • Source- fibroblasts • Components . GAG . Heparin Sulfate . Chondroitin Sulfate . .

Dhaval Bhavsar, Wound Healing (Basics) Angiogenesis • Wound healing requires rich supply to sustain newly formed tissue

• It is evident in erythema (redness) of the new

• density decreases as the need reduces and scar matures

Dhaval Bhavsar, Wound Healing (Basics) Angiogenesis

• Macrophages release- derived angiogenic factor in response to low tissue tension

• Work as chemoattractant

• Basic FGF and VEGF are also important

Dhaval Bhavsar, Wound Healing (Basics) Angiogenesis

• Endothelial cells bud arise from capillary ends

• Produced in line

http://www.med.unibs.it/~airc/angio2.gif • Endothelial cells coalesce and bind Dhaval Bhavsar, Wound Healing (Basics) Re-epithelialization

• Covers the with epidermal cells and completes wound healing

• Re-establishes the barrier

Dhaval Bhavsar, Wound Healing (Basics) Re-epithelialization

• -rich protrusions, lamellipodia and filopodia • Adhesions at the leading edge • Cells move forward by contracting the actin • Coordinated processes of http://www.biochemweb.org/fenteany/research/cell_migration/ assembly, disassembly and turnover

Dhaval Bhavsar, Wound Healing (Basics) Epithelial Migration

http://www.biochemweb.org/fenteany/research/cell_migration/

Dhaval Bhavsar, Wound Healing (Basics) Wound Contraction

• Centripetal movement of wound edges

• Maximal rate of contraction - 0.75 mm/day

• Depends on the degree of tissue laxity and shape of the wound

• Role of

Dhaval Bhavsar, Wound Healing (Basics) Myofibroblast

http://www.grad.ucl.ac.uk/comp/2003/research/gallery/entries/large/016.jpg

Lab Invest 2003, 83:1689-1707

Dhaval Bhavsar, Wound Healing (Basics) Remodeling

• Collagen remodeling – depends on balance between new collagen formation and collagen destruction

• and Matrix

Dhaval Bhavsar, Wound Healing (Basics) Remodeling • Collagen becomes increasingly organized

• Fibronectin gradually disappears

• Hyaluronic acid and glycosaminoglycans are replaced by

• Water is resorbed

• These events allow collagen fibers to lie closer together, facilitating collagen cross-linking

Dhaval Bhavsar, Wound Healing (Basics) Remodeling

• Begins approximately 21 days after

• Remodeling may continue indefinitely

Dhaval Bhavsar, Wound Healing (Basics) Strength of Repaired Wound

• Tensile strength- load capacity per unit area

• Maximum achieved in 90 days

• Usually it is 80% of original strength

• Bursting strength- force required to break a wound regardless of its dimension

Dhaval Bhavsar, Wound Healing (Basics) Clinical Wound Healing

http://www.anat.ucl.ac.uk/business/images/woundhealing.jpg

• Stages are concurrent

• Epithelial migration – 1mm/day

• Requires intervention if larger than 5 cm

Dhaval Bhavsar, Wound Healing (Basics) Burn Wound Healing Superficial Partial • Superficial- primary Deep epithelization

• Partial- From epithelial appendages

• Deep partial- slow epithelization from remaining epithelial appendages

• Deep- Can not epithelize

Dhaval Bhavsar, Wound Healing (Basics) Dhaval Bhavsar, Wound Healing (Basics) Fetal Wound Healing

• Rapid

• Efficient

• Perfect

• Scar less

Dhaval Bhavsar, Wound Healing (Basics) Fetal Wound Healing

• Involves mechanisms similar to and proliferation during embryonic stage of fetal life

• No inflammation

• Wound contraction takes place but no scarring

Dhaval Bhavsar, Wound Healing (Basics) Abnormal Healing

• •

• Chronic non-healing wound

Dhaval Bhavsar, Wound Healing (Basics) Hypertrophic Scar

• Imbalance in collagen production and degradation

• Either over production OR • Low degradation

• Red, elevated http://www.51qe.cn/pic/30/12/17/42/b/01701.jpg Dhaval Bhavsar, Wound Healing (Basics) Hypertrophic Scar

• Usually along tension lines

• occurs more in areas with laxity

http://surgclerk.med.utoronto.ca/Burn/images/scar1.jpg

Dhaval Bhavsar, Wound Healing (Basics) Keloid

• African>Asians> Caucasians

• Comparable to malignant growth

• Extends beyond wound http://www.emedicine.com/derm/images/917dumbellear.jpg margins

Dhaval Bhavsar, Wound Healing (Basics) Non healing Wound

• Wound that fails to progress through an orderly sequence of repair in a timely fashion

• Arbitrary time point: 3-4 http://www.uth.tmc.edu/anes/wound/images/figure_1.jpg weeks

Dhaval Bhavsar, Wound Healing (Basics) Causes of Delayed Wound Healing • Infection • Tissue • Repeated trauma • Presence of necrotic tissue or • Systemic causes • • Malnutrition- •

Dhaval Bhavsar, Wound Healing (Basics) Common Non-healing

Diabetic wound Pressure sore Venus

http://medicine.ucsd.edu/ http://health-pictures.com/images/Decubitus.jpg http://www.bu.edu/woundbiotech/bioengineered

Dhaval Bhavsar, Wound Healing (Basics) Wound Healing & Nutrition

• and A Investigate • Serum protein • Protein • Hemoglobin Essential amino acids

• Micronutrients Mg, Cu, Zn, Fe

Dhaval Bhavsar, Wound Healing (Basics) Tendon Repair

Gross Examination Intermediate phase

Early phase J Hand Surg [Am]. 2003 Sep;28(5):814-23 Late phase

Dhaval Bhavsar, Wound Healing (Basics) Nerve Repair

http://www.northland.cc.mn.us/biology/AP2Online/Fall2001/Nervous/images/neuron_regeneration.gif

Dhaval Bhavsar, Wound Healing (Basics) Bone Repair

http://137.222.110.150/calnet/musculo/image/fracture%20repair%20scheme.jpg

Dhaval Bhavsar, Wound Healing (Basics) THANK YOU

Dhaval Bhavsar, Wound Healing (Basics)