Acellular dermis is a type of biomaterial derived from processing human or animal tissues to remove cells and retain portions of the extracellular matrix (ECM).
These materials are typically cell-free, distinguishing them from classical allografts and xenografts, can be integrated or incorporated into the body, and have been FDA approved for human use for more than 10 years in a wide range of clinical indications.
[1] Although mechanical strength is gained, the artificial crosslinks that are added increase the chance for a host-cell rejection, due to its foreign origin.
[2] Due to this complication, intentional crosslinking is no longer practiced as more recent advancements have been made that increase the lifespan of the collagen without the use of artificial stabilization.
Incorporating devices eventually allow the growth of cells and passage of blood vessels through the matrix, whereas nonincorporating biomaterials are encapsulated by a wall of fused macrophages.
In nonincorporating biomaterials such as Permacol, an acellular porcine dermal implant for hernia repair, it is important that the material is not degraded or infiltrated by the immune system.
In incorporated ECM biomaterials, infiltration by the immune system can occur in as few as seven days, leading to rapid degradation of the device volume.
When ECM biomaterials are added in multiple layers to the ulcer, the wound begins to close quickly and generates host tissue.
Although preliminary studies seem promising, little information is available on the success of and direct comparisons between different ECM biomaterial devices in human trials.