Researchers studying epidermolysis bullosa (EB), using the unusual approach of collecting live cells from discarded wound dressings, have discovered new insights about the condition which could lead to new approaches to treatment and better wound healing.
“Studying wound healing in humans is very challenging, and we know very little about the process in humans,” said Andrew South, PhD, one of the lead authors on the research, in a press release. “What we do know is from animal studies, and animal skin and the way it heals is very different from human skin.”
Dr. South is an associate professor in the Department of Dermatology and Cutaneous Biology at Thomas Jefferson University, Philadelphia.
The research is published online in Scientific Reports (Sept. 15, 2020).
One challenge in treating EB is predicting which wounds will heal on their own, and which will not, Dr. South noted. Taking biopsies is impractical as it is painful for the patient and may slow wound healing even further.
As a potential alternative approach, researchers—including collaborators from Chile and Austria—collected and analyzed 133 discarded wound dressings from 51 EB patients. Samples were collected from both acute and chronic wounds. They defined acute wounds as those that had been present for 21 days or fewer, and chronic as wounds that had been present for more than three months.
This study differed from prior research that collected samples from discarded dressings.
“Previous studies had used wound dressings or bandages to collect fluid and look at what proteins are in there,” said Dr. South. “But no one has actually looked at what cells are present. Applying the techniques our lab frequently uses, we were able to isolate viable or living cells from the dressings.”
The researchers recovered a large number of cells from the dressings, often more than 100 million. The larger the wound, and the more time a dressing was on a wound, the more cells were recovered, according to the release.
Collected samples were then characterized to see what type of cells were present in the wound. Dr. South and his colleagues detected a variety of immune cells including lymphocytes, granulocytes or neutrophils, and monocytes or macrophages.
The investigators found a difference between samples taken from acute wounds and those from chronic wounds. There was a significantly higher number of neutrophils at chronic wound sites.
“Previous findings from animal studies and protein analysis of human wound dressings had supported the idea that when neutrophils hang around longer than they should, that stalls the healing process and can lead to chronicity,” said Dr. South. “Our findings support that theory more definitively, by showing that chronic wounds are characterized by higher levels of neutrophils.”
In the release, the authors suggest that their findings give more insight into wound healing, and could help develop therapies that promote the process. They suggest this could include treatments that neutralize excess neutrophils, or recruit macrophages, which begin the next stage in healing after neutrophils.
The researchers now plan to expand on their technique, by further analyzing the individual cells collected from the wound dressings, and the genetic material inside them.
“Currently we are working with colleagues in Santiago, Chile on collecting dressings from EB patients over a period of time,” said Dr. South. “This allows us to follow patients longitudinally, and observe a wound and how its cellular composition changes as it heals or doesn’t heal.”
The team says they hope that this will reveal genetic markers that can predict healing or chronicity.
“This method of sampling could be an alternative to bothersome swabs or blood draws, which are especially hard to do in newborns,” said Dr. South. “Since we know EB can present at birth, this technique could give us really early insight into the how severe the disease might be.”
Dr. South and his colleagues hope that this technique can be applied to a variety of other conditions, such as diabetic foot ulcers and vascular leg ulcers.
“The field of wound healing has been crying out for a better understanding of what drives a chronic wound,” said Dr. South. “This technique could be transformative, and eventually help patients live more comfortable and healthy lives.”
This study was supported by the Chilean National Fund for Scientific and Technological Development (FONDECYT) Regular, grant number 1181093.
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