Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society
-
Normotrophic, hypertrophic, and keloidal scars are different types of scar formation, which all need a different approach in treatment. Therefore, it is important to differentiate between these types of scar, not only clinically but also histopathologically. Differences were explored for collagen orientation and bundle thickness in 25 normal skin, 57 normotrophic scar, 56 hypertrophic scar, and 56 keloid biopsies, which were selected on clinical diagnosis. ⋯ No differences were found between the different scars. Secondly, compared with normal skin, normotrophic scar, and hypertrophic scar, the bundle distance was significantly larger in keloidal scar, which suggests that thicker collagen bundles are present in keloidal scar. This first extensive histological study showed objective differences between normal skin, normotrophic, hypertrophic, and keloidal scar.
-
Wound healing is compromised by critical colonization and infection with bacteria. Hence, antimicrobial agents are used clinically to decrease the bacterial load and promote wound healing. Polihexanide (PHMB) has been found to be effective against a broad spectrum of micro-organisms and is increasingly utilized in rinsing solutions or in combination with wound dressings because of its good biocompatibility. ⋯ Furthermore, a dressing consisting of biocellulose derived from Acetobacter xylinum with the addition of polihexanide was adept to safeguard keratinocytes against S. aureus. In conclusion, the co-culture system presented embodies a valuable tool as a model system for infected cells in a non-healing wound. Furthermore, the results obtained support the favorable function of polihexanide in the treatment of infected chronic wounds.
-
Homeostasis of the epidermal barrier layer: a theory of how occlusion reduces hypertrophic scarring.
The mechanism of hypertrophic scar reduction using silicone gel sheeting remains elusive. We hypothesize that the decrease in scar formation is due to occlusion and homeostasis of the barrier layer. Using an established model of hypertrophic scarring, rabbits were divided into four groups and scars were tape-stripped or occluded with Kelocote, Cavilon, or Indermil, with each rabbit serving as its own internal control. ⋯ Furthermore, repeated disruption of the permeability barrier by tape stripping led to an increase in scarring. Ultrastructural analysis suggests that occluded wounds may be in an advanced state of wound repair. Occlusion may mediate its effects through establishing homeostasis of the epidermal barrier layer.
-
Previous studies have assessed the effects of changes in microcirculation on wound healing; however, the influence of microcirculation on tissue histomorphology remains widely unknown. Reflectance-mode-confocal microscopy (RMCM) enables in vivo tissue observation on a cellular level. We present RMCM data evaluating the local microcirculation and assess the influence on histomorphology during burn healing. ⋯ Tbl was 14.17+/-0.6 mum (control), increased to 16.93+/-1.15 mum (p<0.05) 12 hours, decreased to 15.93+/-1.20 mum (p<0.05) 32 hours, and to 15.00+/-0.85 mum (p>0.05) 72 hours postburn. Agran was 718+/-56.20 mum(2) (control), increased to 901+/-66.02 mum(2) (p<0.05) 12 hours, decreased to 826+/-56.86 mum(2) 36 hours, and 766+/-65.06 mum(2) at 72 hours postburn. RMCM enables in vivo observation of wound microcirculation and allows direct assessment of vascular effects on cutaneous histomorphology during the healing course of superficial burns.
-
Chronic wounds contain elevated levels of proteases, proinflammatory cytokines, and free radicals. The presence of bacteria further exaggerates the tissue-damaging processes. For successful treatment, the wound dressing needs to manage wound exudates, create a moist environment, inhibit infection, bind pathophysiological factors that are detrimental to wound healing, and provide thermal isolation. ⋯ Incorporation of silver into alginate fibers increased antimicrobial activity and improved the binding affinity for elastase, matrix metalloproteases-2, and the proinflammatory cytokines tested. Addition of silver also enhanced the antioxidant capacity. However, a distinct negative effect of silver-containing alginates on human HaCaT keratinocytes was noted in vitro.