![]() ![]() While a well‐designed system, it is unclear if it could be used to apply clinically relevant pressures to normal healthy skin (NHS) or engineered skin substitutes (ESS) that could be used for skin grafting. This system, or similar, was utilised to study responses to sub‐atmospheric pressures in osteogenic differentiation of adult stem cells,ĭressing types on dermal fibroblast energetics,Īnd cellular proliferation and viability. It also included medium flow below the hydrogels to provide nutrients for longer culture times. This bioreactor incorporated the foam and adhesive with the pressure being applied centrally, similar to clinical applications. developed a bioreactor that applied negative pressure to cell‐seeded hydrogels in a modified six‐well dish. The magnitude of the pressure quickly dissipates with distance from the suction cup where the negative pressure originates leaving many questions regarding mechanisms of action, and the ability to correlate pressure settings to the physiology of wound healing. These pressures also increase proportionally to an increase in pump pressure settings. While negative pressures, or suction, may be found directly under the suction cup, it is evident that there are also positive pressures that exert forces onto the edges of the tissue or wound being treated. NPWT is traditionally applied via a tube with a suction cup placed on top of open‐cell foam with an impermeable adhesive layer placed on top the pressure is measured at the pump and not at the wound site. While this method could be used with intact skin, it does not fully recapitulate the clinical use of NPWT. Many have chosen to apply negative pressure to a chamber in which culture dishes were placed. Multiple groups have studied the responses of cells and tissues to negative pressure. In vitro testing is an important complement to clinical trials and animal studies as it allows control of the environmental conditions, screen several conditions quickly, and study the anatomic and physiologic mechanisms of action of NPWT more easily. While frequently implemented for wound care in the paediatric population, additional studies are still warranted to establish standard treatment guidelines.Ĭurrently, the NPWT devices are approved for wound closure and removal of exudate however, use with skin grafts is not contraindicated per the U.S. NPWT has been shown to lead to decreased graft failure rates,Īlong with increased patient satisfaction. While traditionally used when treating open wounds, NPWT is increasingly being used for closed wounds, fluid management, and as an adjunct to improve skin graft adherence of both meshed and sheet grafts. Negative pressure wound therapy (NPWT) has become the prevailing standard of care for complex acute and chronic wounds however, clinicians have yet to reach a consensus regarding the best practices and mechanisms of action. This bioreactor design can be used to evaluate the impacts of NPWT on the anatomy and physiology of skin to improve outcomes in wounds after grafting with normal or engineered skin. The engineered skin had a similar trend but the differences were not significant. Vascular endothelial growth factor levels were significantly higher in the normal flow‐only group, 152.0 ± 75.1 pg/mg protein, than the other culture conditions, 81.6 ± 35.5 pg/mg for the static and 103.6 ± pg/mg for the negative pressure conditions. The engineered skin underwent apoptosis in the flow‐only group however, the application of negative pressure reduced apoptosis. The normal skin remained viable under all culture conditions. ![]() While it remained intact, there was damage to the epidermal‐dermal junction in the ESS after application of negative pressure. Both skin types were cultured under static, flow‐only, and −75 mm Hg conditions for 3 days. Clinically relevant pressures were applied, and the native human skin was able to withstand greater negative pressures than the engineered substitutes. ![]() ![]() We describe the design and validation of a bioreactor to determine the prospective benefits of NPWT on skin grafts and engineered skin substitutes (ESS). While it is generally agreed that negative pressure leads to improved wound healing, universal consensus on its optimal application is not supported in the literature. Negative pressure wound therapy (NPWT) has become the prevailing standard of care for treating complex soft tissue wounds and is now being considered for use in alternative applications including improving skin graft take. ![]()
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