Spray on skin

Researchers in England are studying the efficacy of spray on skin for the treatment of burn wounds after pilot studies showed remarkable results from a patient with 90% burns. Callan Emery reports.

The body’s skin is too often taken for granted and it is only when it is burnt, cut or otherwise diseased, that one really comes to terms with the essential role that it plays in protecting the body.

In essence the skin acts as a barrier between the body and the environment. Its two most important functions are to prevent fluid loss from the body on the one hand and to prevent infections entering the body on the other.

However, once this all important protection is lost, through a burn wound for example, then the body immediately becomes exposed to the life-threatening fluid loss and deadly infections. And in many cases where a patient has severe burns, where 90% of the skin surface area is lost, they die.

Traditionally, physicians have treated burn patients by first excising the burnt tissue and then grafting skin harvested from a healthy part of the patient’s body on to the burn wound. In large part this treatment works very well and is widely practiced.

However, in cases where a patient has burns covering a large part of the body, treating the burns with the traditional skin graft is not ideal as there is insufficient healthy skin to harvest for the graft. Such cases are often fatal.

Now a treatment under clinical investigation in the United Kingdom could provide new hope for patients with severe burns.

The novel treatment involves science-fictionlike sounding “spray on skin”. It is an ingenious procedure and if the pilot testing is anything to go by, the treatment looks very promising.

One of the researchers, Mr Phil Gilbert, a consultant plastic surgeon and director of the McIndoe Burn Centre at Queen Victoria Hospital, explains: “When a patient with major burns arrives at the Burn Centre an operation is generally indicated within 48 hours. At this time a small skin graft – two square centimetres – is taken for culture in the cell laboratory. It takes two to three weeks to grow sufficient cells. Meanwhile, the burn will have been debrided and dressed with a temporary material. When the cells are ready, widely meshed skin grafts (6:1 or 9:1) are put on the raw area and then the cultured skin cells are sprayed over the top. A non-adherent dressing is applied. The graft is then dealt with in the same way as a normal skin graft.”

Mr Gilbert added: “In pilot studies we get the impression that wounds heal noticeably quicker with less scarring using this spray on method with skin cells. We now need to quantify how good it is at saving lives, repairing wounds and reducing the cost of caring for burns victims.”

Dr Liz James, a cell culture scientist and head of research at the Blond- McIndoe Research Centre at Queen Victoria Hospital, said: “We are conducting the study on two groups of patients; a number of adults with severe burns and 50 children aged between 12 and 36 months with scalds.”

The Blond-McIndoe Research Centre is an independent organisation funded largely through charitable donations. The centre specialises in research in plastic and reconstructive surgery with an emphasis on the treatment of burn injuries and wound healing (www.blondmcindoe.com).

Dr James added: “We have seen what I can only describe as miraculous results using spray on skin with patients surviving 90% burns who otherwise had very little chance of survival.”

Dr James explained that growing skin cells in the lab is not a new procedure. In fact, skin cells have been grown in laboratories since the 1970s. She added that in four weeks enough cells can be grown in the lab to cover the entire body's surface area.

Mr Baljit Dheansa, consultant burns and plastic surgeon at Queen Victoria Hospital, explained to Middle East Health that the skin mesh assists the skin cells to attach and grow on the wound.

“The harvested skin can be stretched up to nine times its original surface area [forming a skin mesh], although we generally stretch it four or six times for this procedure,” he said.

“We’ve found that if we simply spray skin cells straight on to the wound without a skin mesh, they do not readily attach to the tissue.” Mr Dheansa explained that the cells are sprayed on using a fine aerosol.

“The cells are mixed with a liquid, put into a syringe and then pushed through a fine aerosol, which is attached to the syringe.”

Responding to a question as to why they were only conducting these trials now when, as a National Geographic news report stated recently, plastic surgeons at the Royal Perth Hospital in Australia have been using the procedure to treat burn patients for nearly a decade, Mr Dheansa pointed out that although they were doing “very good work at Royal Perth, there was no objective data to say for sure whether spray on skin was in fact a better treatment than the traditional skin graft. There is no comparative data.”

Mr Gilbert added: “Despite the use of sprayed cells reported from Perth, the view is that very many of those patients would have healed satisfactorily without the cells. No truly controlled data is available. “As the whole process of using cultured cells is expensive, the health bodies [in the UK] require evidence of its effectiveness.”

The trials will also determine whether spray on skin improves a patient’s rate of recovery and their final outcome, by providing an objective comparison between this procedure and the traditional skin graft.

Mr Dheansa said in the trial of adult severe burn patients, 25 burn patients would volunteer to receive spray-on cells. Half of each volunteer's wounds would get the spray treatment and the other half would be treated using only the standard graft technique. In this way they could determine the comparative efficacy of the two treatments.

He pointed out that the trials were in their early stages and that they intended to follow up with volunteers for 12 to 18 months after the treatment to fully assess the effectiveness of the procedure.

Mr Dheansa explained that in the trial involving child volunteers with scalds, being carried out jointly with the Royal Victoria Infirmary in Newcastle, the researchers would first give the wound a chance to heal. “If the wound does not heal after about two to three weeks – when scarring would set in – we will spray cells onto the unhealed patch to see if scarring can be avoided.”

According to Dietch et al (1983) a burn wound that takes 21 days or more to heal has a 70% or greater risk of developing a significant scar. A burn wound that heals in less than 10 days has only a 4% risk of developing scar hypertrophy. Mr Gilbert said so far they have not seen any adverse effects from the procedure.

He pointed out that although the procedure is not quicker than conventional skin grafting, the advantage of using spray on skin is the ability to graft much larger areas where there are limited donor sites available. He added that the procedure would also be useful to “patients who have extensive skin loss, or if there is a desire to reduce the size of a graft donorsite.”

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