Expression of inflammatory and fibrogenetic markers in acne hypertrophic scar formation: focusing on role of TGF-β and IGF-1R.

Acne vulgaris is a universal skin disease and it may leave a scar when the original skin lesion disappears. These scars can cause cosmetic problems and psychological burden, leading to poor quality of life of patients. Acne scars are classified into atrophic scars and hypertrophic scars. As most of the acne scars are atrophic, many studies have been conducted focusing on the treatment of atrophic lesions. This study was conducted to investigate the underlying pathogenesis of acne hypertrophic scars by identifying roles of fibrogenetic and inflammatory markers. Skin biopsy samples were obtained from hypertrophic scars of face and back and from adjacent normal tissues as control group. Some samples from back were immature hypertrophic scars and the other samples were in mature stages. Immunohistochemistry staining and quantitative PCR were performed for fibrogenetic and inflammatory markers. Both in mature and immature hypertrophic scars, vimentin and α-SMA were increased. Production of TGF-β3 protein as well as transcription of TGF-β3 was also significantly elevated. In contrast, expression of TGF-β1 showed no increase. Instead, expression levels of SMAD2 and SMAD4 were increased. Elevations of CD45RO, TNF-α and IL-4 and reduction of IL-10 were observed. In immature hypertrophic scars, IGF-1R and insulin-degrading enzyme expression were increased. Increased apoptosis was observed in immature stages of hypertrophic scars but not in mature stages. Elevations of TGF-β3, SMAD2 and SMAD4 in hypertrophic scars and increase of IGF-1R in immature stages may give some clues for acne hypertrophic scar formation.