<i>In vivo </i>pilot study of the effects of a subdermal 1470 nm diode laser on human skin

This in vivo pilot study investigates the histological regenerative effects of a subdermal 1470 nm laser (EndoliftX®, Eufoton® , Trieste, Italy) on human abdominal skin, aiming to assess its role in dermal remodeling. Laser energy was delivered at 5, 20, and 40 J/cm2 to defined areas of abdominal skin in patients undergoing abdominoplasty. Biopsies were obtained at 3 and 6 months post-treatment and assessed for changes in dermal thickness, collagen, and elastin content compared to the control untreated region. Histological staining and image analysis revealed that the 5 and 20 J/cm2 treatments significantly increased dermal thickness and collagen deposition, particularly with the 20 J/cm2 dose, which induced dense, organized collagen bundles indicative of neocollagenesis. Sirius red staining showed increased type III collagen, and Verhoeff-Van Gieson (VVG) staining indicated enhanced and more aligned elastin fibers at moderate energy levels. Conversely, the 40 J/cm2 treatment dose showed signs of collagen fragmentation and reduced elastin coherence, suggesting potential thermal damage. These findings confirm the efficacy of EndoliftX in promoting skin tightening and remodeling at optimal energy settings while highlighting a non-linear dose-response relationship. The results support further development of personalized protocols for minimally invasive procedures in regenerative medicine and aesthetic dermatology.