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The outer root sheath of hair follicles plays an important role in epidermal regeneration in vivo. Keratinocytes isolated by explantation of outer root sheath tissue have extensive proliferative capacity irrespective of donor age, which probably depends on pluripotent epithelial stem cells residing in the outer root sheath. These keratinocytes can be organotypically grown to epidermal equivalents in vitro. We report here that in a multicenter, randomized phase II study, EpiDex trade mark, a tissue-engineered, fully differentiated autologous epidermal equivalent derived from keratinocytes of the outer root sheath of plucked anagen hair follicles, is as effective as split-thickness skin autografting in the promotion of healing and complete closure of recalcitrant vascular leg ulcers.

Background: Maggot therapy (biosurgery) has received increasing interest for the debridement of chronic wounds and for the improvement of wound healing. The purpose of this study was to investigate the clinical effects, side-effects, and possible mechanisms of action of biosurgery., Methods: Biosurgery was used for debridement in 30 patients with chronic leg ulcers of mixed origin. The effect of a single application of maggots for 1-4 days was evaluated by a clinical wound score and contact-free spectroscopy. Side-effects were recorded., Results: Debridement was rapid and selective. The wound secretion was temporarily increased. We observed a significant improvement of the wound score with a decrease from 13.5 +/- 1.8 to 6.3 +/- 2.7 (P < 0.001). The treatment was well tolerated in most patients. Twelve out of 30 patients reported temporary pain, but only two needed analgesic treatment. Other side-effects included venous bleeding in one patient. The remittance spectra showed an improvement of tissue oxygenation as revealed by the characteristic oxygen doublet peak (548 and 575 nm)., Conclusions: Biosurgery is an effective and rapid treatment for the debridement of chronic wounds and the improvement of wound healing. A possible mode of action is the increase in tissue oxygenation. More studies are needed.

Objective wound monitoring is an essential tool for evidence-based medicine in leg ulcers and other chronic wounds. Non-invasive and contact-free optical remittance spectroscopy seems to be a useful approach as it can provide additional information with respect to more traditional techniques of wound scoring. Twenty-three patients with chronic venous, arterial, and mixed leg ulcers were enrolled in this study. The clinical state of the ulcers was documented by a clinical wound score (quantity, color, and consistency of granulation tissue). The spectroscopic readings were performed with a novel diode-array spectrometer system in the visible and near-infrared range of the spectrum (400-1600 nm) with a resolution of 5 nm. The wound spectra mainly depend on the absorption of hemoglobin and water. The maximum correlation coefficients of mean remittance spectra with the clinical wound scores did not exceed +/- 0.5. Discriminant and cluster analysis were applied for spectral classification of wound scores. By using cross-validation the percentage of correct predicted wound scores was about 69%. Our results indicate that the application of optical visible and near-infrared spectroscopy could be a valuable remedy for the clinician.