Head of the Regenerative Therapy Unit at the University Hospital of Lausanne, Professor Lee Ann Laurent-Applegate and her team have developed a biological dressing which stimulates skin regeneration in major burns victims.
When an injured person arrives in a major burns centre, the priority is to avoid infections by recovering their body as quickly as possible. If there is not enough healthy skin, a biopsy on unburnt skin makes it possible to take samples of cells from the epidermis which are placed into a culture to make culture grafts in 10 to 12 days. In Lausanne, the Regenerative Therapy Unit is tirelessly seeking to develop new processes.
A biologist and a specialist in tissue engineering to regenerate skin and musculoskeletal tissues, Lee Ann Laurent-Applegate has been working on skin since the eighties. She and her team have developed banks of progenitor cells in accordance with Good Manufacturing Practice (GMP), which can be used in clinic, and have filed a patent for a biological dressing made of progenitor cells from skin cultivated on a collagen matrix. These cells were obtained from a 2cm2 biopsy of foetal skin, and the organ donation was approved by the Ethics Committee of the Canton of Vaud. The advantage of progenitor cells compared to stem cells is that they are already differentiated into specific cell types, which makes them stable and easy to cultivate, whereas with stem cells, there is always the risk of dedifferentiation (they change cell type). Cells obtained from this single biopsy will facilitate the preparation of at least 1,000 billion biological dressings.
Promising clinical trials
In 2005, two clinical trials – the first in geriatric medicine on people suffering from recalcitrant leg ulcers, the second on children with second degree burns on approximately 20% of their bodies – have demonstrated how effective the dressing is as well as unexpected benefits. “Biological dressing was intended to prepare patients for autografting,” explains Lee Ann Laurent-Applegate, “but the research showed that after 10 to 12 days of treatment, the wounded skin was repaired. The biological dressings stimulated the skin to renew itself and consequently, none of the treated patients needed autografts”. These dressings can be prepared quickly, delivered in 48 hours and applied within ten minutes over the whole body; as they are biodegradable, they can be cleaned with water (the dressings are changed and major burns are washed approximately twice a week.
Clinical trials are on “stand-by” since a change in Swiss Law on transplants, which had regulated tissue and cell transplants with regulations established for organ donations since 2007. They will resume again soon. Lee Ann Laurent-Applegate’s team, in collaboration with the hospital’s lawyers, has resolved the jurisprudential issues for this programme and has achieved GMP standardisation and conformity for the stages of creation and use of this biological dressing. A lot of hard work in order to obtain the key that will enable it to continue their clinical research. “We have been monitoring the first patients treated with biological dressings for more than ten years and we have never seen any problems. I understand why it was necessary to bring the processes of cultivating cells and producing biological dressings into conformity with the standards imposed by the law, it is important for the safety of the patient,” she concludes.