Differential scanning calorimetric examination of pathologic scar tissues of human skin

Abstract

Keloid and hypertrophic scarring is a dermal fibroproliferative disorder characterized by increased fibroblast proliferation and excessive production of collagen. Excess scar formation occurs after dermal injury as a result of abnormal wound healing. Keloid formation has been ascribed to altered growth factor regulation, aberrant collagen turnover, genetics, immune dysfunction, sebum reaction, and altered mechanics. No single hypothesis adequately explains keloid formation. The thermal denaturations of pathologic human skin scar tissues were monitored by a SETARAM Micro DSC-II calorimeter. All the experiments were performed between 0 and 100 °C. The heating rate was 0.3 K min−1. DSC scans clearly demonstrated significant differences between the different types and conditions of samples (intact skin: T m = 54.8 °C and ΔH cal = 4.5 J g−1; normal scar: T m = 53.8 °C and ΔH cal = 4.2 J g−1; hypertrophic scar: T m = 54.2 °C and ΔH cal = 2.4 J g−1; keloid: T m = 52.9 °C and ΔH cal = 8.3 J g−1). The heat capacity change between native and denatured states of samples increased with the degree of structural alterations indicating significant water loosing. These observations could be explained with the structural alterations caused by the biochemical processes. With our investigations, we could demonstrate that DSC is a useful and well-applicable method for the investigation of collagen tissue of the human keloid and hypertrophic scar tissues. Our results may be of clinical relevance in the future, i.e., in the diagnosis of the two different pathologic scar formations, or in the choice of the optimal therapy of the disease.