A Clinical Histology Study Evaluating the Biostimulatory Activity Longevity of Injectable Poly-L-Lactic Acid for Facial Rejuvenation

BACKGROUND: Poly-L-lactic acid (PLLA) is an injectable filler used for restoring facial fat volume loss that improves skin quality. OBJECTIVE: To evaluate the histological changes underlying the observed improvement in skin quality after repeated PLLA injections. METHODS: Ten healthy women were enrolled in this randomized, placebo-controlled, single-center study. Eligible subjects received 3 treatments every 4 weeks with either PLLA (treatment group) or saline (control group) injections, into both sides of the face. Follow-up visits were at week 18 after the last treatment. Assessments included live ratings, patient questionnaires, three-dimensional microtopography imaging analysis, and histological analysis from biopsies taken before and after PLLA treatment. RESULTS: At the 18-week follow-up, there was a significant improvement in investigator- and subject-rated global aesthetic improvement (GAIS) scores, as well as a decrease in wrinkle severity in PLLA-treated but not placebo-treated patients. Skin quality parameters of erythema, pore size, and roughness were significantly improved from baseline and compared with placebo at the 18-week follow-up as assessed by microtopographic analysis and investigator ratings. Histologic analysis revealed increased tissue remodeling and angiogenesis in PLLA-treated tissues at the 18-week follow-up and decreased elastin fragmentation compared with baseline. No treatment-related adverse events occurred. CONCLUSION: Repeated PLLA treatments may improve skin quality through tissue remodeling and neovascularization. J Drugs Dermatol. 2024;23(9):729-734. doi:10.36849/JDD.8057.