Flashlamp pulsed dye laser (PDL) suppression of keloid proliferation through down-regulation of TGF-beta1 expression and extracellular matrix expression.

BACKGROUND AND OBJECTIVES

Keloids have been treated with flashlamp pulsed dye lasers (PDLs) with good results. We investigated whether PDL treatments induced keloid regression by decreasing growth factor-beta(1) (TGF-beta(1)) induction, thereby reducing fibroblast proliferation and collagen deposition.

STUDY DESIGN/MATERIALS AND METHODS: Clinical evaluation and photography documented keloid height/texture, erythema, and pliability before and after PDL treatments scheduled at 2-month intervals in 30 patients. Fluence per pulse was 10-18 J/cm(2) (mean 14.0 J/cm(2)). Immunohistochemical (IHC) staining of TGF-beta(1), proliferating cell nuclear antigen (PCNA), and collagen (types I and III) in extra-cellular matrix was performed on 10 intra-lesional or punch biopsies obtained before and 7 days after PDL treatments.

RESULTS

Twelve months after final PDL treatments, keloid regression ( >/= 50%) had occurred in 26/30 patients in whom erythema and surface irregularities had been reduced and pliability had been increased. In 4/30 patients, no changes in keloids had occurred after 12 months. Multiple treatments ( > 6) yielded better results than fewer treatments: 79% versus 50%, respectively. Marked keloid regression ( >/= 90%) occurred in two patients who had received more than 10 treatments. IHC staining indicated that expression of TGF-beta(1), PCNA and collagen type III, but not type I, was significantly reduced in keloid fibroblasts after PDL irradiation.

CONCLUSIONS

Keloids regressed following PDL-induced reduction in TGF-beta(1) expression, fibroblast proliferation, and collagen type III deposition. More than six PDL treatments at 2-month intervals provided the best results.