Dermal substitutes

Keywords Permacol Integra Skin substitute Dermal substitute Cultured keratinocytes Collagen. Animal model... 

Fig. 25.1 Spraying cultured autologous keratinocytes over Permacol paste dermal substitute biomaterial to achieve epithelialisation of the full-thickness wound...

The biomaterials tested exhibited successful integration, confirming results of previous studies, and the partial wound epithelialisation was achieved by day 21 where either split-thickness skin graft or cultured keratinocytes were applied over dermal substitute biomaterial (Figs. 25.2 and 25.3). 

Fig. 25.2 Survival of a split-thickness skin graft applied over Permacol paste. SSG day 0, assessed 6 days post grafting, haematoxylin and eosin, xlOO. Epithelium of a split-thickness skin graft (SSG) was viable and well-structured. Dermal component of the graft was intimately attached to the well-cellularised Permacol paste PP) with minimal signs of the inflammatory reaction. Dermal substitute biomaterial integrated into the full-thickness wound via granulation tissue in growth present at the paste and wound bed (WB) interface...

Our experiments indicate that cnltnred subconfluent autologons keratinocytes, when applied via aerosol in dermal substitute-grafted full-thickness wonnds, have the ability to snrvive and proliferate in vivo thus contributing to definitive wonnd... 

Take rates of up to 47% have been reported by other researchers if cells were grafted over dermal substitute biomaterial [19]. Other studies where sprayed keratinocytes were combined with alternative dermal substitute Integra , in a similar porcine chamber experimental model, revealed epithelialisation of 20-25%, 21 days post grafting [20], which is in agreement with results of our experiments. It is reasonable to construe that the low percentage of epithelialisation achieved in... 

In an aftermath of large scale natural or man-made disasters there is likely to be lack of donor sites for SSG harvest to treat extensive bums. Use of isolated keratinocytes which can be actively propagated in vitro [24] and applied in vivo along with dermal substitutes may potentially solve the problem of epithelial deficiency and scarring complications, thus reducing the rates of morbidity and mortality in bums critical care. 

Results of our experiments suggest that (1) dermal substitute biomaterials may contribute to the improved wound re-epithehalisation when combined with cultured autologous keratinocytes and (2) porcine collagen paste is able to support splitthickness skin graft survival as well as autologous cultured keratinocyte proliferation. 

This makes the novel collagen paste a suitable alternative to current dermal substitutes to treat acute full-thickness wounds with a potential to be widely used in a bums emergency care. 

Shevchenko RV, Sibbons PD, Sharpe JR, James SE (2008) Use of a novel porcine collagen paste as a dermal substitute in fuU-thickness wounds. Wound Repair Regen 16(2) 198-207... 

Wisser D, Steffes J (2003). Skin replacement with a collagen based dermal substitute, autologous keratinocytes and fibroblasts in burn trauma. Burns. 29 375-380. 

Fujimori Y, Ueda K, Fumimoto H, Kubo K, Kuroyanagi Y. Skin regeneration for children with burn scar contracture using autologous cultured dermal substitutes and superthin auto-skin grafts preliminary clinical study. Ann Blast Surg 2006 57 408-414. 

W. Haslik, L.-P. Kamolz, G. Nathschlager, H. Andel, G. Meissl, M. Frey, First experiences with the collagen-elastin matrix Matri-derm as a dermal substitute in severe burn injuries of the hand. Bums 33 (2007) 364-368. 

Kuroyanagi, Y., Yamada, N., Yamashita, R., and Uchinuma, E. (2001), Tissue-engineered product Allogeneic cultured dermal substitute composed of spongy collagen with fibroblasts, Artif. Organs 25(3) 180-186. 

The ideal dermal substitute obviously needs to integrate into the wound in which it has been implanted, by allowing the invasion into it of fibroblasts, other cells, and angio-genetic vascular buds/vessels from the wound bed. Once estabfished, the fibroblasts need to be stable enough to lay down autologous collagen. 

From the outset it was necessary that any biodegradable polyurethane intended for use as a dermal substitute would need to be nontoxic to cells (noncytotoxic) and support the growth of fibroblasts (and their production of collagen) and keratinocytes. Ultimately, in the wound, the matrix would need to sustain blood vessel in-growth to supply the overlying skin-grafted epidermis with nutrients, oxygen, immune cells, and factors, and transport out the toxic by-products of cellular respiration. Therefore, microvascular endothelial cells (MVECs) would also need to thrive in the presence of BTM. 

Klein B, Schiffer R, Hafemann B, Klosterhalfen B, Zwadlo-Klarwasser G. Inflammatory response to a porcine membrane composed of fibrous collagen and elastin as dermal substitute. J Mater Sci Mater Med. 2001 12 419-24. 

Helary, C., Bataille, I., Abed, A., Illoul, C., Anglo, A., Louedec, L., Letourneur, D., Meddahi-Pelle, A., and Giraud-Guille, M. M. (2010). Concentrated collagen hydrogels as dermal substitutes. Biomaterials 31, 481 90. 

Skin substitutes currently available vary in complexity, ranging from temporary synthetic wound dressings to permanent skin replacements, either with or without incorporation of cultured skin cells (Table 47.1). Some of the acellular materials have components that incorporate into the wound bed and may become populated with dermal cells from the host. These dermal substitutes replace the dermal component of the... 

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