Critical phase of healing Flashcards

1
Q

What is tissue healing?

A

Innate mechanism residing in healthy tissue

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2
Q

Examples of excessive healing

A

Scleroderma

Keloid scarring

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3
Q

Examples of impaired healing

A

Diabetes

Vitamin C deficiency

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4
Q

What governs tissue healing?

A

Genetic factors.

Mechanism is embedded in our tissues since birth

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5
Q

What are the 3 stages of tissue healing?

A
Inflammatory stage (4-6)
Proliferative stage (2-24) 
Remofelling stage (21-2 years)
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6
Q

What happens in the inflammatory stage?

A

Swelling and warmth around the wound

Inflammatory mediators go to the wound

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7
Q

What happens in the proliferative stage?

A

New blood vessels grow through the wound
Fibroblasts first lay down ECM to close wound
The fibroblasts then fully differentiate into myofibroblasts that lay donw new connective tissue and fully repair the wound site

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8
Q

What happens during the remodelling stage?

A

Tissue is normalised
Inflammation subsides
Tissue is repaired

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9
Q

What releases growth factors that promote wound healing during the inflammatory process?

A

Clots

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10
Q

What are some of the growth factors released by clots that promote wound healing?

A

TGF-b and PDGF

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11
Q

How does the epithelial layer respond in response to these growth factors?

A

Proliferates and divides to cover wound

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12
Q

How does expression of the collagen gene change during repair process?

A

Highest expression in day 7

Lower in the beginning

Main protein in ECM

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13
Q

What is the role of PGE2?

A

Dilates and makes blood vessels more leaky

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14
Q

When is PGE2 maximally expressed?

A

Early in the wound repair process

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15
Q

Why is wound healing important clinically?

A

Non-healing wounds is a common and costly medical problem

No effective treatment for excessive wound healing or non-healing pathologies

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16
Q

What is scleroderma an example of?

A

An excessive wound healing pathology

17
Q

What do patients with scleroderma present with?

A

Generalised scar tissue formation of surface of internal organs and surface skin

18
Q

What causes persistent wound healing?

A

Constantly activated fibroblasts

19
Q

What is the role of fibroblasts?

A

Lay down more scar tissue and contract the wound

Release pro-fibrosis growth factors

Important proteins/ genes inolved include NfxB, TGFv and MRTFA

NfxB and MRTFA lead to collagen production

20
Q

What is the role of stem cells in wound healing?

A

Activated following tissue injury

Migrate out to the tissues to orchestrate repair processes

DIfferentiate into myofibroblasts