A Polylactic Acid Dermal Matrix for Wound Epithelialization in Pyoderma Gangrenosum

Dr. Jose Ramirez-GarciaLuna shares background and key details from his poster, “Using a Polylactic Acid Dermal Matrix for Achieving Wound Epithelialization in Patients with Pyoderma Gangrenosum,” presented at SAWC Fall 2023 in Las Vegas, NV.

Transcript

Jose L. Ramirez-Garcialuna, MD, PhD:

Hi. My name is Jose Ramirez-Garcialuna. I'm a medical doctor. I'm originally from Mexico. I was trained there, then immigrated to Canada to do a PhD in experimental surgery. Right now, I'm affiliated to McGill University in Canada. I'm a surgery professor there.

And the part that I'm discussing today is the use of PLA matrices on pyoderma gangrenosum. And as most people should well know, pyodermas are one of the hardest to heal ulcers. And the fact that that's the reason is because pyodermas are inflammatory ulcers. So, what's happening there is neutrophils in the wound bed start eating away the tissues, start eating away all the repaired tissue that's been produced. So, as new repair tissues are produced, neutrophils come, eat it, and destroy it. And this is one of the hallmarks of disease. So, we all know that this kind of ulcer, if you go there and debride the wound bed, the next day, the wound will be larger. And this is because you are flaring up inflammation and the cells are starting to eat away the other tissue. So, these ulcers, people live with them for long periods of time, are hard to heal, and are refractive to usual treatment modalities.

What we decided to do in this in this research was we used PLA matrices, or polylactic acid matrices, on the wound bed. PLA is a material that has been out there a long time, it's deemed to be safe and biocompatible. And this novel material, as it sits in the wound bed, gets degraded down to lactate monomers, and lactate exerts very powerful effects in the wound bed.

The first one is that it is angiogenic, so cells recognize it and produce a TGF response to it. Second, it is immunomodulatory, so cells recognize it and then upregulate genes that produce immunoregulation, bring down inflammation, reduce the motility of cells, particularly neutrophils and macrophages. And then the third component is that it also promotes the growth of cells. Cells grow faster, epithelium comes faster, collagen deposition is faster and so on. Finally, the pH of the wound bed also becomes a little bit more acid. It falls down for around 1.5 to 1 pH units. And by achieving this neutral pH, it's an environment that is that is more conducive for an appropriate healing.

So taken together, when you put these material into the wound bed, in theory, the wound bed shrinks, and you get better healing. However, we didn't know if this was the case for inflammatory ulcers. These properties that I discussed were very interesting, and we thought it made sense to use that on an inflammatory ulcer. We were very surprised to see that when you put it on the wound bed, the wound bed actually, the inflammatory nature of the ulcer shifts and becomes a granulating tissue. So the epithelium comes fast. The wounds close very fast, and we were very surprised with that.

We also used, a novel imaging technology, which is called infrared thermal imaging. And infrared imaging, again, it's not a new technology, but it's novel in medicine. I have done some research with this technology for a few years, and what we have demonstrated is that there is a correlation on the number of blood vessels in the wound tissue and the temperature of the wound bed.

And what was really surprising to see in the beginning with pyoderma ulcers was they're very, very cold. So usually, what we see, for example, in diabetic foot ulcers, is that these are also around 2 to 3 degrees colder than the surrounding tissue. However, for pyodermas, the difference in temperature is around 7 to 8 degrees, which is very, very cold. And this indicates a lack, a profound lack, of blood vessels in the wound bed. So, this is one of the features in thermal imaging we were very surprised by it in the beginning.

But the second part was even more surprising was that whenever we applied PLA, you could see a shift in the wound bed temperature. So, in the beginning, the wound bed starts to get hotter. It goes to around the 2- to 3-degree difference. And then at some point, the temperature equalizes, meaning that the blood vessels and the tissue is receiving, an adequate blood supply, and that's when the epithelialization occurs.

So, by using this technology, we can track and we can really see the inflammatory effects of PLA, and we can also see the healing proceeding. So, we believe it's a very powerful technology, not only fight for pyodermas, but for other ulcers as well as it allows us to identify different etiologies and response to treatment.