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Stromal cells from subcutaneous adipose tissue seeded in a native collagen/elastin dermal substitute reduce wound contraction in full thickness skin defects.

BACKGROUND
Dermal substitutes seeded with cultured fibroblasts have been developed to improve dermal regeneration in full thickness wounds. Because of cell cultivation, 3 weeks are required before patients can be treated with these autologous adipose tissue. This substitute is easily fabricated within hours, which allows immediate treatment of full thickness defects.


EXPERIMENTAL DESIGN
Porcine full thickness wounds were substituted with native collagen/alpha-elastin hydrolysate matrices. One group of matrices was left unseeded as negative control. The second was seeded with cultured dermal fibroblasts as positive control. The third was seeded with a stromal-vascular-fraction of adipose tissue, and the fourth was seeded with a stromal fraction with few vascular fragments (SF). All substitutes were covered with split skin mesh grafts and were protected against dehydration and infection with a microporous polyether urethane membrane. For 8 weeks, weekly biopsies were taken, myofibroblasts and fibroblasts were counted, thickness of the granulation tissue band was measured, and wound contraction and histology were evaluated.


RESULTS
Negative control and stromal-vascular-fraction substitutes were invaded by high numbers of myofibroblasts and fibroblasts. They did not reduce wound contraction, and scar tissue was formed. SF substitutes reduced the accumulation of myofibroblasts and fibroblasts and prevented the formation of granulation tissue. As a result, dermal regeneration improved, and wound contraction was less than by the other substitutes.


CONCLUSIONS
Adipose tissue cell isolates included vascular fragments containing endothelial cells. Seeded in dermal substitutes, these vascular fragments induced hypergranulation tissue formation and caused wound contraction. SF substitutes contained few endothelial cells. As a result, the contraction arresting effect of the seeded stromal cell fraction was effective. Our concept of a cellular dermal substitute seeded with stromal cells from adipose tissue is feasible and allows immediate treatment of full thickness skin defects.