Healthy Healing

Biologist Luisa Ann DiPietro: Reducing Scarring and Speeding Healing

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Luisa DiPietro Optimizes Healing

Dentist and biologist DiPietro works to change the way we view healing.

Healing

• Is a regenerative series of events

• Involves >12 cell types and >100 molecules

• Can go awry

Question:

Do all types of tissue heal equally well?

Photo: Bill Wiegand

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Answer: No

Different types of tissue heal better than others.

• Skin tissue is more likely to scar than are mucous membranes

• Slippery tissues inside the nose, ears, mouth, and other body cavities heal faster than skin tissue

• Diseased tissue in arteries may not completely heal

• Wounds in people with some diseases may heal more slowly than those of healthy people

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Stages of Healing

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Inflammation in Cells

1. Neutrophils are the first cells to respond to injury

2. Macrophages clean up debris

3. Mast cells induce swelling, warmth, and redness

4. All 3 types of cells summon more immune system cells

Wound cells

Photo: Copyright Dennis Kunkel Microscopy, Inc.

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Angiogenesis

1. New vessels grow and cover wound

2. New vessels bring oxygen and nutrients to wound

3. Proteins grab the edges of wound and close it, forming a protective mesh

4. Excess new vessels die off

Scar

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Too Much of a Good Thing?

• Excess inflammation can damage healthy, neighboring tissues

• Excess inflammation can be life-threatening

• Excess angiogenesis can worsen scarring

In what types of human cells does this NOT occur?

How does this happen?

When is inflammation potentially dangerous?

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DiPietro's Gnawing Problem

• As a dentist, DiPietro knew that severe scarring is rare in tissue with mucous membranes, such as mouth tissue

• As a biological researcher, DiPietro wants to know why the same is not true of other types of tissue, like skin

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Knowledge By Comparison

• Approach #1: Compare how lab-grown, human skin and mouth cells respond to injury

• Approach #2: Compare healing process of injured skin and tongues in mice

In vitro experiment

In vivo animal experiment

DiPietro's Approaches to Better Understand Healing

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Many Unanswered Questions

• What causes scarring?

• Why does your mouth scar so much less severely than your skin?

• Can we learn from these differences?

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Research Applications

Can you think of a new way to prevent scarring?