The Longevity of a Bilayered Skin Substitute After Application to Venous Ulcers

BACKGROUND: A bilayered skin substitute composed of allogeneic keratinocytes and fibroblasts in a collagen gel has been approved by the US Food and Drug Administration for the treatment of venous and diabetic ulcers. Its mechanism of action has not been fully determined. OBJECTIVE: To determine the longevity of allogeneic fibroblasts and keratinocytes in a bilayered skin substitute in patients with venous leg ulcers. METHODS: Ten patients with venous leg ulcers were treated with a bilayered skin substitute on day 0, days 3 to 5, and weeks 1 through 3. Biopsy specimens of the grafted wound were taken. We used polymerase chain reaction analysis to determine whether allogeneic DNA was present in the biopsy specimens. RESULTS: We detected allogeneic DNA in 2 of 8 specimens at 1 month after initial grafting. Neither of the 2 patients showed persistence of allogeneic DNA at 2 months after initial grafting. CONCLUSIONS: Allogeneic cells from a bilayered skin substitute do not appear to survive permanently after grafting for treatment of venous leg ulcers. Other mechanisms of action might include cytokine release, structural support, or provision of a moist wound environment.