Paula Denman of the Queensland University of Technology used QCIF's High Performance Computers to model the growth of skin cell colonies for the development of a new aerosolised burns treatment.

Severe burns can be very traumatic for the patient and often life-threatening. The commonly applied technique of taking epidermal cells from an unburnt area of the patient’s body, expanding them in culture,  then grafting the resultant skin sheet onto the patient’s burn to provide permanent coverage has several disadvantages:

• it may take 3 to 4 weeks for the graft to be available
• the skin cell sheets are hard to handle, as they are very fragile and the sheets often have poor attachment in areas such as joints, hands and the face where there is complex topography or mechanical forces 
• treatment can be prohibitively expensive - it has been estimated that the cost of treatment was around US $110,000 per adult during the period from 1990 to 1995

Paul's new method involves taking skin cells known as keratinocytes from an area of the patient's undamaged skin, culturing the cells in a laboratory, encouraging them to rapidly proliferate over a period of 5-10 days, and then harvesting and separating the cells from each other.  The cells are then suspended in aerosolization medium, and sprayed onto the wound surface, where they migrate and proliferate, eventually covering the wound.  This method is claimed to result in faster healing and better quality re-epithelialisation than CEA, with better delivery of cells at a substantially reduced cost.

Figures 1 and 2 show frames from simulations showing the coverage of skin cells over time, for different initial spatial distributions.  Figure 1 shows the coverage assuming the initial positions of the colonies were chosen randomly from a normal distribution.  Figure 2 shows the coverage assuming the initial positions of the colonies were chosen randomly from a uniform distribution.  The wound area is 20 mm × 20 mm.  In each case, there are 15 colonies initially - 3 highly active colonies (shown in red), 5 moderately active colonies (green) and 7 least-active colonies (blue).  Black regions indicate quiescent cells.  Frame 1 of each figure shows the initial distribution of colonies (t=0), while frames 2 to 4 show the coverage after 8, 16 and 24 days respectively.

For the case of the normal distribution, the wound is essentially completely healed after 21 days.

Participants

Paula Denman, Professor Sean McElwain
School of Mathematical Sciences, QUT

Publications

Denman, P.K., McElwain, D.L.S., Harkin, D.G. and Upton, Z. "Mathematical Modelling of Aerosolised Skin Grafts Incorporating Keratinocyte Clonal Subtypes", Bulletin of Mathematical Biology, accepted 06/02/06, available online.

Denman, P.K., McElwain, D.L.S. and Norbury, J. "Analysis of Travelling Waves Associated with the Modelling of Aerosolised Skin Grafts", Bulletin of Mathematical Biology, accepted 04/05/06, available online.