[Management of complications after aesthetic hyaluronic acid injections]

Time- and Dose-Dependent Effects of Hyaluronidase on the Degradation of Different Hyaluronan-Based Fillers In Vitro

BACKGROUND

Hyaluronidase (HYAL) is regarded as the standard for the management of complications associated with hyaluronan (HA)-based fillers. Therefore, the understanding of interactions of HA fillers and HYAL is essential.

METHODS

Nine different commercially available HA fillers (Belotero, Juvéderm, and Restylane) with varying degrees of cross-linking were used for the analysis. Fluorescently dyed HA fillers were individually incubated with varying doses of HYAL [bovine HYAL (Hylase "Dessau"; Riemser Pharma, Germany); 5, 10, and 20 U/mL] or sodium chloride and monitored by time-lapse microscopy. HA filler degradation was assessed as a decrease in fluorescence intensity of HA filler plus HYAL compared to HA filler plus control, quantified by computerized image analysis.

RESULTS

HA fillers show significant differences in their reaction to HYAL. Levels of degradation of HA fillers are positively correlated with increasing concentrations of HYAL. At the highest concentration of HYAL (20 U/mL), all fillers except one (Belotero Volume) reached a significant level of degradation at 5 to 9 hours.

CONCLUSIONS

In this study, the authors show that most HA fillers can be dissolved by HYAL in a dose- and time-dependent manner. Of note, the fillers' technology and degree of cross-linking seem to exert stronger effects on the degradability by HYAL as compared to the concentration of HA.

CLINICAL RELEVANCE STATEMENT

The authors' in vitro analyses support clinical recommendations stating that in the case of a vascular filler incident, HYAL should be applied early and at significant doses ("Time is skin!").

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Dose- and time-dependent effects of hyaluronidase on structural cells and the extracellular matrix of the skin

Introduction

Hyaluronic acid (hyaluronan; HA) is an essential component of the extracellular matrix (ECM) of the skin. The HA-degrading enzyme hyaluronidase (HYAL) is critically involved in the HA-metabolism. Yet, only little information is available regarding the skin’s HA–HYAL interactions on the molecular and cellular levels.

Objective

To analyze the dose- and time-dependent molecular and cellular effects of HYAL on structural cells and the HA-metabolism in the skin.

Materials and methods

Chip-based, genome-wide expression analyses (Affymetrix® GeneChip PrimeView™ Human Gene Expression Array), quantitative real-time PCR analyses, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (DAB), and in vitro wound healing assays were performed to assess dose-dependent and time-kinetic effects of HA and HYAL (bovine hyaluronidase, Hylase “Dessau”) on normal human dermal fibroblasts (NHDF), primary human keratinocytes in vitro and human skin samples ex vivo.

Results

Genome-wide expression analyses revealed an upregulation of HA synthases (HAS) up to 1.8-fold change in HA- and HYAL-treated NHDF. HA and HYAL significantly accelerated wound closure in an in vitro model for cutaneous wound healing. HYAL induced HAS1 and HAS2 mRNA gene expression in NHDF. Interestingly, low concentrations of HYAL (0.015 U/ml) resulted in a significantly higher induction of HAS compared to moderate (0.15 and 1.5 U/ml) and high concentrations (15 U/ml) of HYAL. This observation corresponded to increased concentrations of HA measured by ELISA in conditioned supernatants of HYAL-treated NHDF with the highest concentrations observed for 0.015 U/ml of HYAL. Finally, immunohistochemical analysis of human skin samples incubated with HYAL for up to 48 h ex vivo demonstrated that low concentrations of HYAL (0.015 U/ml) led to a pronounced accumulation of HA, whereas high concentrations of HYAL (15 U/ml) reduced dermal HA-levels.

Conclusion

HYAL is a bioactive enzyme that exerts multiple effects on the HA-metabolism as well as on the structural cells of the skin. Our results indicate that HYAL promotes wound healing and exerts a dose-dependent induction of HA-synthesis in structural cells of the skin. Herein, interestingly the most significant induction of HAS and HA were observed for the lowest concentration of HYAL.

Majocchi's granuloma caused by Trichophyton rubrum after facial injection with hyaluronic acid: A case report

BACKGROUND

Facial cosmetic procedures become popular for people with a desire to have a younger appearance, and cosmetic technology has developed rapidly over the past several decades. However, increasing complications related to cosmetic injections have been reported, and infection is one of the most serious problems and can cause anxiety and facial injury. We here report a case of Majocchi's granuloma (MG) caused by Trichophyton rubrum after facial injection of hyaluronic acid.

CASE SUMMARY

A 37-year-old woman presented to our hospital with a history of red papules, nodules, and abscesses on her left zygomatic arch for 2 mo. She had received a cosmetic injection of hyaluronic acid on the left side of her face prior to the appearance of the lesions. MG caused by Trichophyton rubrum after facial injection of hyaluronic acid was diagnosed based on morphology and molecular biological identification. In vitro antifungal susceptibility testing was conducted according to the Clinical and Laboratory Standards Institute M38-A2 method. Minimal inhibitory concentrations were used to evaluate the antifungal susceptibility. The antifungal agents and their minimal inhibitory concentrations for the strain were terbinafine (< 0.5 μg/mL), itraconazole (0.06 μg/mL), amphotericin B (0.25 μg/mL), fluconazole (32 μg/mL), voriconazole (0.125 μg/mL), posaconazole (0.125 μg/mL), and isavuconazole (0.06 μg/mL). We initially administered 250 mg/d oral terbinafine for 2 mo, but the patient still had painful papules, nodules and abscesses on her face. Then, we adjusted the treatment to itraconazole 400 mg/d for 8 wk based on the in vitro antifungal susceptibility testing results. The skin lesions improved significantly, and there was no recurrence during follow-up.

CONCLUSION

This case revealed that facial injection of hyaluronic acid may cause serious MG. Antifungal susceptibility testing should be considered in the treatment of MG caused by Trichophyton rubrum.

Clinical Applications of Hyaluronidase

Hyaluronidases are enzymes that degrade hyaluronic acid, which constitutes an essential part of the extracellular matrix. Initially discovered in bacteria, hyaluronidases are known to be widely distributed in nature and have been found in many classes including insects, snakes, fish and mammals. In the human, six different hyaluronidases, HYAL1-4, HYAL-P1 and PH-20, have been identified. PH-20 exerts the strongest biologic activity, is found in high concentrations in the testicles and can be localized on the head and the acrosome of human spermatozoa. Today, animal-derived bovine or ovine testicular hyaluronidases as well as synthetic hyaluronidases are clinically applied as adjuncts to increase the bioavailability of drugs, for the therapy of extravasations, or for the management of complications associated with the aesthetic injection of hyaluronic acid-based fillers. Further applications in the fields of surgery, aesthetic medicine, immunology, oncology, and many others can be expected for years to come. Here, we give an overview over the molecular and cellular mode of action of hyaluronidase and the hyaluronic acid metabolism, as well as over current and potential future clinical applications of hyaluronidase.

Standardized in vitro analysis of the degradability of hyaluronic acid fillers by hyaluronidase

Background

Hyaluronidase is a hyaluronic acid (HA) metabolizing enzyme, which is approved as an adjuvant for infiltration anesthesia. The “off-label” use of hyaluronidase is regarded as gold standard for the management of HA-filler-associated complications. Yet, up to date there are only few studies that have systematically assessed the degradability of different HA-fillers by hyaluronidase.

Objective

To analyze the interactions of HA-fillers and hyaluronidase in a time-dependent manner using a novel standardized in vitro approach.

Methods

Comparable HA-fillers, Belotero Balance Lidocaine (BEL; Merz), Emervel classic (EMV; Galderma) and Juvederm Ultra 3 (JUV; Allergan), were incubated with a fluorescent dye and bovine hyaluronidase (HYAL; Hylase “Dessau”, Riemser) or control (NaCl) and monitored by time-lapse videomicroscopy. The degradation of HA-fillers was assessed as decrease in fluorescence intensity of HA-filler plus hyaluronidase vs. HA-filler plus control, quantified by computer-assisted image analysis (ImageJ).

Results

Hyaluronidase showed a significant degradation of the HA-fillers BEL and EMV. Degradation was measurable at 5 h (BEL) and 7 h (EMV), respectively; significance was reached at 14 h (BEL) and 13 h (EMV). No effect of hyaluronidase was observed for JUV.

Conclusion

Time-lapse microscopy enables systematically, standardized, comparative in vitro analyses of the interactions of hyaluronidase and HA-fillers.

Hyaluronidase: from clinical applications to molecular and cellular mechanisms

Over the past 60 years, hyaluronidase has been successfully utilized in ophthalmic surgery and is now being implemented in dermatosurgery as well as in other surgical disciplines. The enzyme is considered a “spreading factor” as it decomplexes hyaluronic acid (also called hyaluronan, HA), an essential component of the extracellular matrix (ECM). When applied as an adjuvant, hyaluronidase enhances the diffusion capacity and bioavailability of injected drugs. Therefore, the enzyme has been used as a local adjuvant to increase the diffusion capacity of local anesthetics, increasing the analgesic efficacy, and the anesthetized area particularly in the first minutes following injection, resulting in diminished intra- and postoperative pain. In aesthetic medicine, the off-label use of hyaluronidase is considered the gold standard for the management of HA-filler-associated complications. Here, we review the clinical use, underlying biological mechanisms, and future directions for the application of hyaluronidase in surgical and aesthetic medicine.