Poly-L-Lactic Acid Filler Increases Adipogenesis and Adiponectin in Aged Subcutaneous Tissue

Poly-L-lactic acid (PLLA) filler, which increases volume and collagen synthesis, is used for skin rejuvenation. Subcutaneous adipose tissue (SAT) contains precursors that differentiate into mature adipocytes that secrete adiponectin, which modulates SAT function and increases adipogenesis. During aging, adiponectin and precursor cell functions decrease, reducing adipogenesis and facial volume. Adiponectin also increases collagen synthesis by stimulating fibroblasts. After hydrogen peroxide treatment to induce senescent adipocytes (3T3-L1) and aged skin, follow-up PLLA treatment increased adipogenesis by stimulating the nuclear factor erythroid-2-related factor 2 (NRF2)/peroxisome proliferator-activated receptor gamma (PPARγ)/CCAAT/enhancer binding protein alpha (C/EBPα) pathway. This resulted in increased adiponectin secretion, which promoted collagen synthesis and mitigated the loss of SAT volume. In the senescent adipocyte, PLLA increased NRF2/PPARγ/C/EBPα, adipogenesis factors (fatty acid binding protein 4, lipoprotein lipase, and cluster of differentiation 36), lipogenesis factors (ATP citrate lyase, acetyl-CoA carboxylase, and fatty acid synthase), adiponectin, and lipid droplet size. Treatment of senescent fibroblasts with conditioned medium from PLLA-treated adipocytes increased collagen1 and 3 and decreased matrix metalloproteinase1 and 3 expressions. Similarly, PLLA increased NRF2/PPARγ/C/EBPα, adipogenesis, and lipogenesis factors in aged mouse SAT. Also, PLLA increased adiponectin and adipocyte numbers without hypertrophy and increased collagen accumulation and dermal thickness. In summary, PLLA increased adipogenesis and adiponectin, which increased the volume of SAT and collagen synthesis, thereby rejuvenating aged skin.