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 b een 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 cellular substitutes. We developed a dermal substitute seeded with stromal cells derived from autologous a dipose tissue. This substitute is easily fabricated within hours, whic h allows immediate treatment of full thickness defects. EXPERIMENTAL D ESIGN: Porcine full thickness wounds were substituted with native coll agen/alpha-elastin hydrolysate matrices. One group of matrices was lef t unseeded as negative control. The second was seeded with cultured de rmal fibroblasts as positive control. The third was seeded with a stro mal-vascular-fraction of adipose tissue, and the fourth was seeded wit h a stromal fraction with few vascular fragments (SF). All substitutes were covered with split skin mesh grafts and were protected against d ehydration and infection with a microporous polyether urethane membran e. For 8 weeks, weekly biopsies were taken, myofibroblasts and fibrobl asts were counted, thickness of the granulation tissue band was measur ed, and wound contraction and histology were evaluated. RESULTS: Negat ive control and stromal-vascular-fraction substitutes were invaded by high numbers of myofibroblasts and fibroblasts. They did not reduce wo und contraction, and scar tissue was formed. SF substitutes reduced th e accumulation of myofibroblasts and fibroblasts and prevented the for mation of granulation tissue. As a result, dermal regeneration improve d, and wound contraction was less than by the other substitutes. CONCL USIONS: Adipose tissue cell isolates included vascular fragments conta ining endothelial cells. Seeded in dermal substitutes, these vascular fragments induced hypergranulation tissue formation and caused wound c ontraction. SF substitutes contained few endothelial cells. As a resul t, the contraction arresting effect of the seeded stromal cell fractio n was effective. Our concept of a cellular dermal substitute seeded wi th stromal cells from adipose tissue is feasible and allows immediate treatment of full thickness skin defects.