Estudo da remodelação dérmica induzida pela aplicação intradérmica do ácido hialurônico na pele fotoenvelhecida

Hyaluronic acid (HA) filler is an important dermatological procedure for the treatment of wrinkles and facial volume loss. The HA gel is generally degraded in 3 to 9 months, but many studies reported sustained clinical effect longer than the half life of HA gel. The objectives of this study were to evaluate the clinical and histological results of a HA filler injection and to quantify dermis remodeling at 3 and 9 months after HA injections into aged faces. Twenty female patients were enrolled in this study, aged between 40 and 50 years (45.8 ± 3.6), Fitzpatrick skin phototypes III and IV, nasolabial folds between grades 3 and 5 of the wrinkle scale of Genzyme. HA filler was injected into the nasolabial folds and preauricular regions of the patients. Skin biopsies of the preauricular regions were performed before the procedure and at 3 and 9 months after the procedure. There was a good clinical effect of the treatment performed after one, three, six, nine and twelve months. The immunohistochemistry study was performed on 10 of the 20 patients randomly chosen, in which we analyzed the expression of metalloproteinases, enzymes responsible for the remodeling of extracellular matrix (MMP-1, 3, 7, 9, 13), of the metalloproteinase inhibitor (TIMP-1 and 2) and collagen type I and III at T0, T3 and T9. For statistical analysis of the clinical, histopathological, morphometric and immunohistochemistry data, the Wilcoxon test and descriptive analysis were used, according to the criteria evaluated. Clinically, all patients improved the degree of depth of the nasolabial folds in the scale of Genzyme (p 0.05) after 9 months. The percentage of the area occupied by HA gel over the entire biopsy fragment ranged from 35.4 ± 9.2% after 3 months of application of the gel, to 35.2 ± 9.6% after 9 months. Immunohistochemistry showed a decrease in MMP-1 and 13 in T3 and T9 (p < 0.05).Thus, we can conclude that intradermal injection with HA gel can lead to sustained clinical improvement not only by the gel present in the skin, but also for all the effects of remodeling of the dermis and epidermis after the procedure, as observed in this study.