Here - EWMA 2013

Key Session: Regenerative Medicine
7
Regenerative medicine in burn wound healing: aiming for the
perfect skin
Magda Ulrich 1
1 Association of Dutch Burn Centres (Beverwijk, Netherlands).
Healing of full thickness wounds, such as burn wounds, is still complicated by
(hypertrophic) scar formation and contraction. Standard treatment is transplantation with
autologous split thickness skin graft. In extended burns the grafts have to be widely
meshed because of limited donor sites. This often results in a poor functional and
cosmetic outcome. Application of cultured autologous keratinocytes (CK) may enhance
wound closure and improve scars. In 1979 the first epidermal substitute, a confluent
epithelial sheet, was developed. These CEA (cultured Epidermal Autografts) have been
used in burn patients with variable success.
Due to the variation in efficacy new strategies have been employed and currently the
application of preconfluent proliferating keratinocytes is considered a better strategy.
In addition to the epidermal grafts, the outcome of healing may improve with the
application of dermal substitutes. Over the past decades several scaffolds to mimic the
dermis have been developed. These substitutes can be supplemented with growth
factors and cells.
8
Distinct contribution of stem and progenitor cells
to epidermal maintenance
Key Session: Regenerative Medicine
Guilhem Mascré 1 , Sophie Dekoninck 1 , Benjamin Drogat 1 , Khalil Kass Youssef 1 ,
Sylvain Brohée 1,2 , Panagiota A. Sotiropoulou 1 , Benjamin D. Simons 3,4 , Cédric Blanpain 4,5
1 Université Libre de Bruxelles, IRIBHM, (Bruxelles, Belgium);
2 Université Libre de Bruxelles, Machine Learning Group (Bruxelles, Belgium);
3 Cavendish Laboratory, Department of Physics, University of Cambridge (Cambridge,
United Kingdom);
4 The Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge
(Cambridge, United Kingdom);
5 WELBIO, Université Libre de Bruxelles (Bruxelles, Belgium).
The skin interfollicular epidermis (IFE) is the first barrier against the external environment
and its maintenance is critical for survival. Two seemingly opposite theories have been
proposed to explain IFE homeostasis. One posits that IFE is maintained by long-lived
slow-cycling stem cells (SCs) that give rise to transit-amplifying (TA) cell progeny, while
the other suggests that homeostasis is achieved by a single committed progenitor (CP)
population that balances stochastic fate. Here, we probed the cellular heterogeneity
within the IFE using two different inducible CREER targeting IFE progenitors.
Quantitative analysis of clonal fate data and proliferation dynamics demonstrate the
existence of two distinct proliferative cell compartments arranged in a hierarchy involving
slow-cycling SCs and CP cells. Following wounding, only SCs contribute substantially to
the repair and long-term regeneration of the tissue, while CP cells make a minimal and
transient contribution.
The discovery of mesenchymal stem cells (MSC), especially the presence of these stem
cells in subcutaneous fat has opened new opportunities for cell based tissue
engineering.
Several papers have shown that MSC reduce fibrosis. Initially the general idea was that
MSC were incorporated into the damaged tissues and differentiated into the tissue
specific cells. However it is now becoming clear that these cells exert their main
therapeutic effect through paracrine actions and their immune regulatory features, and to
a lesser extent through the incorporation into the damaged tissue.
KEY SESSION: REGENERATIVE MEDICINE
EWMA 2013
COPENHAGEN
15-17 May · 2013
Danish Wound
Healing Society
23