Hyaluronidases for treating complications by hyaluronic acid dermal fillers: evaluation of the effects on cell cultures and human skin

Hybrid Shear-thinning Hydrogel Integrating Hyaluronic Acid with ROS-Responsive Nanoparticles

Nanoparticle (NP) supra-assembly offers unique opportunities to tune macroscopic hydrogels' mechanical strength, material degradation, and drug delivery properties. Here, synthetic, reactive oxygen species (ROS)-responsive NPs are physically crosslinked with hyaluronic acid (HA) through guest-host chemistry to create shear-thinning NP/HA hydrogels. A library of triblock copolymers composed of poly(propylene sulfide)-bl-poly(N,N-dimethylacrylamide)-bl-poly(N,N-dimethylacrylamide-co-N-(1-adamantyl)acrylamide) are synthesized with varied triblock architectures and adamantane grafting densities and then self-assembled into NPs displaying adamantane on their corona. Self-assembled NPs are mixed with β-cyclodextrin grafted HA to yield eighteen NP/HA hydrogel formulations. The NP/HA hydrogel platform demonstrates superior mechanical strength to HA-only hydrogels, susceptibility to oxidative/enzymatic degradation, and inherent cell-protective, antioxidant function. The performance of NP/HA hydrogels is shown to be affected by triblock architecture, guest/host grafting densities, and HA composition. In particular, the length of the hydrophilic second block and adamantane grafting density of self-assembled NPs significantly impacts hydrogel mechanical properties and shear-thinning behavior, while ROS-reactivity of poly(propylene sulfide) protects cells from cytotoxic ROS and reduces oxidative degradation of HA compared to HA-only hydrogels. This work provides insight into polymer structure-function considerations for designing hybrid NP/HA hydrogels and identifies antioxidant, shear-thinning hydrogels as promising injectable delivery platforms for small molecule drugs and therapeutic cells.

In Vitro Evaluation of the Biological Availability of Hyaluronic Acid Polyethylene Glycols-Cross-Linked Hydrogels to Bovine Testes Hyaluronidase

During last years, hyaluronic acid- (HA-) based dermal fillers have grown rapidly and continuously, as reported by the American Society of Aesthetic Plastic Surgery (ASAPS). In fact, HA fillers are considered the gold standard technique for soft tissue augmentation, deep skin hydration, and facial recontouring, playing a key role as an alternative to plastic surgery. HA fillers are less invasive, more biocompatible, and safer and with a more natural and immediate result if compared to plastic surgery. Hence, the safety of HA-based dermal fillers plays a crucial role, mostly in terms of biocompatibility and adjustability in case of unpleasant results and side effects such as, tyndall effect, edema, or granulomas. Hyaluronidase is a naturally occurring enzyme, present in the human body, and can degrade HA fillers avoiding more severe complications. In this article, we analyzed the bioavailability of hyaluronidase degradation of five fillers of Neauvia® hydrogels line (MatexLab SA, Lugano, CH), composed of pure hyaluronic acid and based on PEGDE cross-linking (polyethylene glycol) technology that guarantees a higher biocompatibility and an optimal biointegration and rheological characteristics. The performed in vitro testing is based on the colorimetric determination of the N-acetyl-D-glucosamine (NAG) present in solution after incubation with hyaluronidase, determined at different time points in order to assess the kinetic of each product degradation (1h, 3h, 6h, 24h, 48h, 72h, 120h, and 168h). The aim of this study was to assess, in vitro, how the difference in HA content and PEGDE concentration of the analyzed fillers can influence the product biocompatibility, intended as product enzymatic clearance and duration in time. The results demonstrated that the method was reproducible and easy to perform and that all the analyzed fillers are naturally immediately available for hyaluronidase-mediated degradation.

Early hyaluronidase use in preventing skin necrosis after treatment with dermal fillers: Report of two cases

Injection of dermal fillers, like hyaluronic acid (HA), is a safe procedure, with few and transient side effects such as erythema, bruising and swelling etc. The aim of this report is to provide our protocol for the early treatment of necrotic complications after facial treatment with dermal fillers. We present two cases of skin suffering of the face after dermal infiltration of HA, treated successfully with our early protocol. Our protocol includes the early infiltration of hyaluronidase in the treated areas. We start with infiltration of hyaluronidase distributed over the area to be treated through micro-injections with dosage 40 IU per cm 2. Our protocol includes the use of systemic corticosteroids for 4 days, anti-aggregation therapy, oral antibiotic, topical cream with nitric oxide and compresses with gauze and warm water. In the skin complications after dermal filler treatment, marked pain and characteristic reticulated erythema in the skin distribution of the affected vessels is often developed. Due to the implementation of our protocol in these patients, we managed to avoid an irreversible necrotic complication of the face in both cases. In this report, our protocol was compared with results published in the literature and allowed us to avoid complications such as skin necrosis with permanent damage.

Early hyaluronidase use in preventing skin necrosis after treatment with dermal fillers: Report of two cases

Injection of dermal fillers, like hyaluronic acid (HA), is a safe procedure, with few and transient side effects such as erythema, bruising and swelling etc. The aim of this report is to provide our protocol for the early treatment of necrotic complications after facial treatment with dermal fillers. We present two cases of skin suffering of the face after dermal infiltration of HA, treated successfully with our early protocol. Our protocol includes the early infiltration of hyaluronidase in the treated areas. We start with infiltration of hyaluronidase distributed over the area to be treated through micro-injections with dosage 40 IU per cm 2. Our protocol includes the use of systemic corticosteroids for 4 days, anti-aggregation therapy, oral antibiotic, topical cream with nitric oxide and compresses with gauze and warm water. In the skin complications after dermal filler treatment, marked pain and characteristic reticulated erythema in the skin distribution of the affected vessels is often developed. Due to the implementation of our protocol in these patients, we managed to avoid an irreversible necrotic complication of the face in both cases. In this report, our protocol was compared with results published in the literature and allowed us to avoid complications such as skin necrosis with permanent damage.

Labia Majora Augmentation with Hyaluronic Acid Filler: Technique and Results

BACKGROUND

External female genitalia lose elasticity and volume with age. In the literature several techniques address the redundancy of the labia minora, but only few reports describe the augmentation of labia majora with fat grafting. At present, no studies describe the augmentation of the labia majora with hyaluronic acid.

OBJECTIVES

This study aims to present our technique of infiltration of hyaluronic acid filler, analyzing effectiveness, patient satisfaction, and complications.

METHODS

We retrospectively analyzed 54 patients affected by hypotrophy of the labia majora; they were treated with hyaluronic acid filler between November 2010 and December 2014. The Global Aesthetic Improvement Scale (GAIS) filled out by the doctor and the patients was used to evaluate the results 12 months after the infiltration. Complications were recorded.

RESULTS

A total of 31 patients affected by mild to moderate labia majora hypotrophy were treated with 19 mg/mL HA filler; 23 patients affected by severe labia majora hypotrophy were treated with 21 mg/mL HA filler. Among the first group of patients, one underwent a second infiltration 6 months later with 19 mg/mL HA filler (maximum 1 mL). A significant improvement (P < .0001) in GAIS score was observed, both in the scores provided by the patients and by the doctor. A greater relative improvement was observed in patients affected by severe hypotrophy. No complications were recorded.

CONCLUSIONS

Hyaluronic acid infiltration of the labia majora is able to provide a significant rejuvenation with a simple outpatient procedure. We achieved significant improvements with one infiltration in all cases. The treatment is repeatable, has virtually no complications and it is reversible.

LEVEL OF EVIDENCE

4 Therapeutic.