Background: Hyaluronic acid (HA) dermal fillers are commonly used in cosmetic dermatology. Due to differences in their physical characteristics, HA fillers demonstrate different sensitivity to degradation by hyaluronidase (Hase) because of HA concentration and differences in cross-linking. Similarly, there are differences in the activity of Hase products depending on source and concentration.
Objective: The primary objective was to demonstrate the differences in potency and activity of 5 Hase products when used to degrade 5 different HA products using a human in vivo model.
Materials and methods: The study subject was a healthy, consenting adult woman scheduled to undergo abdominoplasty. Skin to be excised was injected with 0.1 to 0.2 mL of each filler (10 injections each) leaving a visible lump. Immediately afterward, the HA lumps were injected with 4 IU of each Hase product every 2 minutes until the HA lumps were no longer visible or palpable. This procedure was repeated after 30 days. Injected tissues were excised after abdominoplasty for histological analysis.
Results: The 5 Hase products displayed a wide range of doses and times required to completely degrade the 5 HA products ranging from <2 to >16 minutes.
Conclusion: Cosmetic practitioners should familiarize themselves with differences in HA and Hase products.