AN IN-VIVO MODEL OF HUMAN PROLIFERATIVE SCAR

Background. Many aspects related to the biology and the effective ther apy of proliferative scars have remained undefined, in part due to a l ack of an accurate and reproducible animal model with which to systema tically study them. This report describes a new model for investigatin g the pathophysiology and manipulation of human proliferative scars. M aterials and methods. Human proliferative scars (n = 86) were explante d into flaps based on isolated vascular pedicles in congenitally athym ic rats. Serial analysis of the structural and functional integrity of the explanted scars was performed by microscopy and by measurement of human procollagen type III peptide (PIIIP) production, human factor V III immunostaining, and in vitro cellular proliferation. Results. By t hese methods, both fibroblastic and epithelial components of explanted scar specimens retained the histologic characteristics of original hu man scar specimens, for up to 12 months. Over the same duration, scar explants continued to have high levels of human PIIIP, comparable to t hose found in original surgical specimens. The microvasculature of sca r explants demonstrated a double basement membrane, with no staining o f human factor VIII in the inner capillary endothelial layer, suggesti ng that host vessels were growing into ghost vessels of the human dono r scar. Human factor Vm staining decreased over time, Fibroblasts cult ured from explanted scar demonstrated less aggressive growth character istics than those from original surgical specimens. Conclusions. This new model is the first to allow such long-term maintenance and serial evaluation of human proliferative scar on an accessible, isolated vasc ulature, It may prove useful in further defining the biology and thera py of this widespread pathologic process. (C) 1998 Academic Press.