Tapping into the Influence of Keratinocyte Allografts and Biocenosis on Healing of Chronic Leg Ulcers: Split-Ulcer Controlled Pilot Study

BACKGROUND: Cultured keratinocytes may represent an alternative therapy aiming at boosting leg ulcer healing. There is no evidence-based study comparing objectively the healing rate of split-ulcer portions covered or not covered by cultured keratinocytes. OBJECTIVE: To assess the effect of cultured keratinocytes on the healing rate of leg ulcers. METHOD: Five applications of fresh (cela, XCELLentis, Ghent, Belgium) or frozen (CryoCeal, XCELLentis) cultured allogeneic keratinocytes were performed at weekly intervals to treat large leg ulcers (mean diameter > 5 cm) in four patients. A split-ulcer study was designed to secure a control area covered only by petrolatum gauze. Clinical, planimetric, bacteriologic, and immunohistologic assessments of the keratinocyte-treated and control parts of the ulcers were performed. RESULTS: Compared with controls, planimetry revealed a beneficial effect afforded by cryopreserved cultured keratinocytes on the ulcer healing rate of two of four ulcers (+12 and 81%). The healing effect was obtained on the ulcers associated with the lowest bacterial load. Cultured keratinocytes did not qualitatively and quantitatively modify the ulcer biocenosis. They did not affect the number of any type of inflammatory cells present in the granulation tissue (type I dermal dendrocytes, macrophages, T lymphocytes, granulocytes). No specific side effect of cultured keratinocytes was evidenced. CONCLUSION: In this small case series, it appears that cultured allogeneic keratinocytes may be helpful in the healing process of venous leg ulcers. However, a clean wound with reduced bacterial load seems to be the prerequisite condition for obtaining a beneficial effect.