The role of fractional carbon dioxide laser in modulating smooth muscle actin expression in Keloid and Hypertrophic scars

Background Keloids (K) and hypertrophic scars (HTS) are challenging due to their disfiguring nature and tendency to recur. The immunohistochemical expression of α-smooth muscle actin (α-SMA), which reflects fibroblast activity, may be influenced by fractional carbon dioxide (fCO 2 ) laser therapy, potentially improving scar appearance, and texture. Objective To assess the effects of fCO 2 laser treatment on the histopathological and clinical characteristics of K and HTS, focusing on the expression of α-SMA as a marker of treatment efficacy. Patients and methods This interventional study was performed on 30 patients with either K or HTS. Participants underwent three sessions of fCO 2 laser treatment. Scar assessments were conducted using the Vancouver Scar Scale, and skin biopsies were taken pre and post-treatment for histopathological and immunohistochemical analysis of α-SMA expression. Results Significant improvements were noted post-treatment, with reductions in scar erythema, pain, and pruritus ( P <0.05). The mean size of lesions also showed a significant decrease ( P <0.05). Furthermore, α-SMA expression notably decreased, with a reduction in strongly positive cases from 80% pretreatment to 10% post-treatment and an increase in negative cases from 10 to 60%. Overall, patient satisfaction correlated positively with these improvements. Conclusion fCO 2 laser treatment significantly alters the clinical and histopathological profiles of K and HTS, reducing α-SMA expression and improving overall scar quality.