Reversing facial fillers: interactions between hyaluronidase and commercially available hyaluronic-acid based fillers.

INTRODUCTION: Hyaluronidase (HA) degrades hyaluronic acid, allowing flexibility in the use of hyaluronic acid-based fillers commonly used in facial correction. Potentially differing properties of available hyaluronidases and fillers may influence their interaction, leading to important differences in ultimate cosmetic results. This study examines the physical properties of various fillers after exposure to commonly available hyaluronidases in vitro to better inform their in vivo clinical use.

METHODS: Four commonly used HA fillers were exposed to varying concentrations of Vitrase (ovine testicular hyaluronidase) and Hylenex (human recombinant hyaluronidase) in vitro. The gross properties of these fillers were then observed to evaluate time- and dose-response; photographs were obtained to allow visual comparison at 1 minute and 5 minutes post-exposure.

RESULTS: At a concentration of 0.1 mL Vitrase to 0.2 mL filler, Restylane dissipated most followed by Juvéderm; Belotero most retained its form. Hylenex at the same concentration showed similar results, again affecting Restylane most and Belotero least. Response to treatment with both hyaluronidases increased substantially over time, increasing progressively from exposure to 5 minutes post-exposure. When exposed to Hylenex at 15 U and 30 U to 0.2 mL filler, Belotero retained its form most, followed by Juvéderm, Juvéderm Voluma, and then Restylane. The effects on filler structure increased with 30 U concentration vs 15 U concentration of Hylenex.

DISCUSSION: Available hyaluronidases and HA fillers appear to have differing physical properties that influence their interaction in a time and dose-dependent manner. Knowledge of the ways in which specific fillers interact with different hyaluronidases may help achieve desired cosmesis when aiming to adjust delicate facial fillers.