The use of poly-L-lactic acid in case of involutional changes in the body skin: clinical, ultrasound and histological assessment of effectiveness

Relevance. Injection preparations of poly-L-lactic acid (PLLA) are widely used to correct age-related skin changes and soft tissue volume deficiency. The stimulating effect of PLLA on atrophic skin changes is realized at different levels and affects various mechanisms of aging. The clinical effect of PLLA administration may vary depending on the depth of administration, as well as on the volume of water used for dilution, that is, on the final concentration of the active substance. Objective. Evaluation of the effectiveness and safety of PLLA administration in different concentrations and at different levels using objective methods: ultrasound and histological diagnostics. Material and methods. PLLA was administered in the abdominal area to four healthy volunteers with signs of sagging skin in various dilutions and at different depths. The effect of the injection was evaluated after 4 and 6 weeks based on visual examination and photo documentation, ultrasound and histological analysis of tissue biopsies in the injection area. Results. Upon visual examination, the clinical effect in the form of compaction and alignment of the skin relief of the anterior abdominal wall began to manifest itself 14 days after the PLLA injection and tended to increase. The most pronounced clinical results were obtained 4—6 weeks after administration of PLLA. The ultrasound pattern after 4—6 weeks was characterized by an increase in the acoustic density of the dermis. After 6 weeks, more pronounced results were achieved when the filler was administered at the level of the border of the dermis and hypodermis when 150 mg of PLLA was reconstituted by 10 ml of water for injection and when it was administered at the hypodermic level using 20 ml of water for injection for reconstitution. Analysis of the histological picture showed an increase in the density of collagen fibers after the treatment with PLLA. Conclusion. The positive dynamics of the clinical picture after the injection of PLLA in the form of compaction and alignment of the skin relief occurs with structural changes indicating the accumulation of connective tissue fibers in the area of administration of polylactic acid. Thus, from a clinical point of view, the body treatment with PLLA is effective and safe.