In vitro optimisation of topical negative pressure regimens for angiogenesis into synthetic dermal replacements.

Background: The use of synthetic dermal replacements (SDRs) in the treatment of large wounds, which have associated morbidity and mortality, has attracted great interest. However, because of poor outcome, SDRs have limited use. The addition of topical negative pressure (TNP) has increased their success, but little research has focused on the underlying mechanisms. This paper studies the in vitro effects of TNP on commonly used SDRs to identify the most effective TNP regimen and optimum SDR for encouraging endothelial cell ingress.

Methods: Endothelial cells were co-cultured in vitro on four SDRs with or without TNP. Negative pressure (125mmHg) was applied intermittently, continuously, for 4h per day, or not at all. Endothelial ingress was measured for each condition.

Results: In the collagen controls, cell migration was minimal. Integratrade mark gave the greatest endothelial cell migration (p<0.05, n=3). TNP increased endothelial cell migration, intermittent application being the optimum regimen.

Conclusions: Integratrade mark has an open sponge structure which may account for greater angiogenicity than Allodermtrade mark, Permacoltrade mark and Xenodermtrade mark. In vitro intermittent TNP stimulates the greatest angiogenic response. The majority of clinical studies investigating SDR success with TNP have used continuous regimens; this study suggests a change in clinical practice to intermittent application.