A minimally invasive human in vivo cutaneous wound model for the evaluation of innate skin reactivity and healing status.

Individual variability in skin reactivity and healing capacity after trauma are important clinical issues. The aims were to develop an in vivo, human wound model based on a standardised minimal skin injury and to demonstrate therapeutic effect of simple wound therapies in terms of morphological wound outcome with changes in skin blood perfusion as a quantified indicator of wound healing. In a series of experiments, wounds were induced on the normal forearm skin of volunteers using a blood collection lancet. This was well tolerated. Wounds were assessed by naked eye examination or laser Doppler perfusion imaging (LDPI) at baseline and at up to 6 further time points up to 96 h in control wounds and wounds treated by commonly used occlusive dressing options. Assessment by clinical observation with 10x magnification showed over 96 h a progression of erythema, surface crust, a new keratinisation layer and finally healed areas. LDPI quantifying wound erythema showed a peak at 24 h and near normal levels at 96 h. Inter-individual variability was evident but intra-individual variability was much less pronounced. Wounds treated with occlusion showed a statistically significant more rapid return to baseline blood perfusion as measured by LDPI compared to controls supported by favourable healing parameters in the clinical assessment. The paper exemplifies use of non-invasive, bioengineering technique for quantification of individual innate variability in skin reactivity, wound healing capacity and therapeutic effect in a well-tolerated in vivo, human, minimal skin trauma model.