Researchers seek better approach to healing wounds

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September 1, 2011 - 7:00pm

On a warm summer day in Lincoln, an easy game of catch can be a good way to enjoy the day. That's what Leigh Gramke and a friend did recently. A pretty normal thing for Gramke, who's been playing softball most of her life.

"T-ball when I was in kindergarten, first grade, I don't know, a long time ago," she said. "I was good at it."

Good enough that she played one season of college softball. Now, though, playing catch is about the only thing she can do with the sport she loves. It all changed last December.

"I was coming home after a night and just lost control of my car and went into a creek, and the car caught on fire," she said. "A couple just happened to be following me, and saw my lights disappear, and pulled me out of the vehicle and saved my life."


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Forty percent of Gramke's body was burned. That required special care at the Burn Center at St. Elizabeth Regional Medical Center in Lincoln. There are numerous examples of the marvels of modern medicine, from progress in neonatal care to robotic surgery. But there are some areas of medical care that haven't advanced as far as others; one of those is the treatment and recovery of skin-related wounds.

Scientifically, skin is a complex combination of cells and genes, part of the reason new treatments have been difficult to come by. Skin normally heals by developing a scar, which is an unorganized refashioning of those layers. That creates issues like flexibility and mobility for victims, along with cosmetic concerns.

Dr. David Voigt is a co-director of the Burn Center at St. Elizabeth.

"The skin is actually dead," he explained. "And so, depending upon how many layers of the skin are dead depends upon whether the burn will heal on its own or whether it's gonna require excision and grafting to get that wound to close. Anything that takes longer than 21 days to heal, we tell the patients they're better off having a skin graft. Anything that heals in less than 14 days, we tell them they're better off without a skin graft.

"Between the 14- and 21-day period, we tell them they have to trust us," he continued. "For us, it depends on where the burn is. It's gonna be different if it's a burn to the hand than if it's the middle of the thigh."

Skin grafting is not a modern marvel, however. It's been state-of-the-art for burn healing for decades. But research efforts in Nebraska could advance the treatment of wounds. Dr. Mark Carlson is a surgeon and researcher with a dual appointment at the University of Nebraska Medical Center and the Department of Veterans Affairs Medical Center in Omaha.

"Skin grafting is where the doctor will shave an area of skin off the patient, off the burned patient, but from an area where there's no burn. And then apply that piece of shaved skin to where the burn is."

"It's kind of an imperfect solution," he said. "Right now, in 2011, skin grafting is the best treatment we have for burns. It's been that way for 70 years. Despite all the research that we've done on trying to develop skin replacements, and we have some, the best skin replacement we have today is still the patient's own skin in the form of a skin graft. And so, that's why there are thousands of laboratories across the world, including mine, trying to devise a better skin replacement."

Carlson is working on the development of a liquid bandage. Its first application would be to stop bleeding quickly. The U.S. Department of Defense is funding the research, looking for solutions in battlefield settings. But Carlson is also working on a regenerative medicine approach where the liquid bandage would help new skin grow, in addition to stopping the bleeding of a wound. He shows a sample that looks much like a piece of gauze.

"You have your liquid bandage, which can kind of mold to whatever surface that you are trying to treat. This is a form in its mesh form. This actually would be more of the configuration that we would use to create a new piece of skin. Now, of course, this isn't there yet. The actual new piece of skin in the culture dish would contain cells and growth factors and other things, but this would be kind of a starting point to make that new piece of skin."

Carlson's approach to the problem isn't the only one being explored in Nebraska.

In a research lab in Lincoln, a different approach is underway to try to improve wound healing. Clague Hodgson, founder of Nature Technology Corporation, is also searching for better solutions. He points to a centrifuge that spins up to 25,000 times per minute.

"As that liquid goes down through that tube, it's being splattered against the walls of the centrifuge," he said. "And there's a blanket there that catches all that material."

Nature Technology develops gene-based therapies and vaccines. It takes plasmid, which is a segment of DNA that can be replicated. Placed in a fermenter filled with e coli for more than 40 hours, the liquid then goes to the centrifuge and comes out as a paste, creating copies of the plasmid that can be used for medical and cosmetic purposes. Among other things, Hodgson said the process addresses the cost-effectiveness of gene therapy treatments.

"Basically, we start out with a molecule that's been cut and pasted together in the test tube," he said. "And we've got just one or a few copies of that molecule. So we now put it in a test tube with a bacterial cell and we use an electric shock to introduce the DNA molecule through the bacterial cell wall into the bacterium, where it's now in an environment where it can actually grow. It actually co-ops the host cells replication machinery to allow it to replicate that DNA, the same replication machinery that's being used to replicate the host cell DNA.

"So the host has a number of enzymes, called DNA preliminaces, that allow the DNA to replicate, and so by co-opting it, we can grow thousands of copies of our plasmid inside the bacterial cell," he continued. "So we feed it a very nutritious broth, which you've seen growing in the lab. And over a period of about 44 hours, we get a very high density of bacterial cells. And we then use temperature induction to allow the plasmid to replicate at the expense of the bacteria. And the end result is a very high concentration of plasmid.

"We've got basically, the highest published yields of plasmid DNA, which is about two and a half grams per liter. And a gram is an awful lot of plasmid DNA. For a medicine, you might need a few micrograms, or millionths of a gram. So a gram is a lot of doses of plasmid."

What Hodgson envisions is production of a topical cream that would aid healing when applied to a wound. But what Nature Technology is doing is an early step in the process. It's the pre-clinical stage of testing. Other companies will now conduct animal testing, and if successful, only then can human trials occur. Still, Hodgson sees the potential benefits from this process for healing wounds.

"The best example is probably burns," he said. "You've probably seen these awful pictures of humans who have burns over large areas of their body. And in many cases, they're basically a living bacterial plate. Any microorganism that lands on them is a source of potential infection. And in many cases, it's a long process. So if you can speed that process up by a factor of three, it makes a huge difference."

With skin grafting being the best current approach to healing, that requires taking healthy skin to repair wounds. In a way, that doubles the size of a burn victim's injuries and provides another incentive to find a quicker way to heal or a new way to repair wounds that a liquid bandage might address.

For Leigh Gramke, that could have meant being back on the softball field this summer instead of taking a year off. She spent about four months at St. Elizabeth recovering from her burn injuries. Much of that time was healing from a skin graft operation just in time to do another one.

"I'd get up walking and doing my regular stuff and they'd have to all start over like two weeks after that," she said. "It takes a lot of patience. And a lot of strength to get through it, because it's kind of a lingering pain. You have it throughout the whole time you're here."

But slowly, Gramke is getting back in the game.

"I'm hoping I can get to running again," she said. "I don't know if I'll be as good as before the injury, but I'm hoping at least jogging."

She probably won't be able to resume her college softball career, but her goal is recreational softball by next year. Maybe by then, researchers will be closer to a new way to treat burn injuries that will get others back on the playing field in a shorter amount of time.

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