Keloids are thick fibrous scars that are refractory to treatment and unique to humans. The lack of keloid animal models has hampered development of effective therapies. The authors' goal was to develop an animal model of keloids using grafted engineered skin substitutes composed of keloid-derived cells. To demonstrate the model's utility, differences between deep and superficial keloid fibroblasts were investigated.
Engineered skin substitutes were prepared using six combinations of cells: 1, normal keratinocytes and normal fibroblasts; 2, normal keratinocytes and deep keloid fibroblasts; 3, normal keratinocytes and superficial keloid fibroblasts; 4, keloid keratinocytes and normal fibroblasts; 5, keloid keratinocytes and deep keloid fibroblasts; and 6, keloid keratinocytes and superficial keloid fibroblasts. Engineered skin substitutes stably grafted to athymic mice were evaluated for wound area, thickness, and gene expression.
Deep keloid fibroblasts displayed elevated expression of type 1 collagen alpha 1 (COL1A1), transforming growth factor β-1, periostin, plasminogen activator inhibitor 2, and inhibin beta A compared with superficial keloid fibroblasts and normal fibroblasts. After grafting, engineered skin substitutes in group 5 were significantly thicker than controls and had increased COL1A1 expression. Engineered skin substitutes in group 6 showed significantly increased area. Histologic analysis revealed abnormal collagen organization in engineered skin substitutes containing deep keloid fibroblasts or superficial keloid fibroblasts.
Aspects of the phenotypes of engineered skin substitutes prepared with keloid cells are analogous to thickening and spreading of human keloid scars. Therefore, use of keloid engineered skin substitutes is a valuable new tool for the study of keloid scarring.
From the Research Department, Shriners Hospitals for Children–Cincinnati, and the Department of Surgery, University of Cincinnati College of Medicine.
Received for publication September 20, 2011; accepted December 13, 2011.
Presented in part at the 42nd Annual Meeting of the American Burn Association, in Boston, Massachusetts, March 9 through 12, 2010.
Disclosure:Dr. Boyce is the inventor named on patents assigned to the University of Cincinnati and Shriners Hospitals for Children according to their intellectual property policies. Patents and other intellectual property pertaining to engineered skin substitutes are licensed to Cutanogen Corporation, which was founded by Dr. Boyce, and in which he has past and present financial interests; however, he has no authority or responsibility for Cutanogen's current activities. The remaining authors have no conflicts of interest to declare.
Dorothy M. Supp, Ph.D.; Shriners Hospitals for Children–Cincinnati, 3229 Burnet Avenue, Cincinnati, Ohio, 45229, email@example.com