A new technique for combining pre-vascularized sheets of dermal stem cells with split-thickness skin grafts (STSG) may improve the treatment of large, full-thickness burn wounds, according to findings published in Theranostics (2017; 7(1):117–131).
Researchers from Michigan Technological University in Houghton, Mich., and First Affiliated Hospital of Sun Yat-sen University in Guangzhou, China noted in the paper that combining STSG with a dermal substitute has previously been attempted in order to overcome some of the limitations of large STSGs such as contraction, however vascularization problems have led to unsatisfactory outcomes.
To try to overcome these problems, they developed a technique for producing pre-vascularized sheets of human mesenchymal stem cells (hMSCs).
The investigators compared cultured hMSC cell sheets to pre-vascularized hMSC cell sheets in a rat full thickness wound model. The cell sheets were implanted, and then covered with autologous STSGs. Both types of cell sheet significantly reduced skin contraction and improved cosmetic appearance compared to a STSG-alone control group. However, the pre-vascularized group had the least hemorrhage and necrosis, and also the lowest level of inflammatory cell infiltration.
“The engineered stem cell sheet will overcome the limitation of current treatments for extensive and severe wounds, such as for acute burn injuries,” senior author Feng Zhao, BME, an associate professor of biomedical engineering at Michigan Tech, said in a press release, “and significantly improve the quality of life for patients suffering from burns.”
Both the STSGs and hMSCs are hard to harvest, noted Zhao, and they are mechanically fragile, so improved harvesting technologies will need to be developed.
Larger studies in pig models and eventually in humans are also needed.