A high crosslinking grade of hyaluronic acid found in a dermal filler causing adverse effects

Performance assessment of an injectable hyaluronic acid/polylactic acid complex hydrogel with enhanced biological properties as a dermal filler

Injectable hyaluronic acid (HA) hydrogel plays an important role in dermal filling. However, conventional HA dermal fillers mostly lack bio-functional diversity and frequently cause adverse reactions because of the chemical stiffness of highly modified degree and crosslinker residues. In this study, polylactic acid (PLA) was embedded into HA hydrogel as a bioactive substance and 1,4-butanediol diglycidyl ether was used as a crosslinker to prepare the HA/PLA composite hydrogel with enhanced biocompatibility and biological performance. We aimed to investigate the properties of HA/PLA composite hydrogels as dermal fillers by assessing the rheological properties, surface microstructure, enzymolysis stability, swelling ratio, degradation rate, cytotoxicity, and anti-wrinkle effect on photo-aged skin. The results showed that the stability and stiffness of the composite hydrogel decreased with an increasing amount of PLA, while the in vivo safety of the HA/PLA hydrogel was enhanced, showing no adverse reactions such as edema, redness, or swelling. Moreover, the composite hydrogel with 2 wt% PLA exhibited excellent anti-wrinkle effects, showing the highest collagen production. Thus, the PLA-embedded HA composite hydrogel showed potential as a dermal filler with high safety, easy injectability, and excellent anti-wrinkle effects.

Injectable Hyaluronan-Based Thermoresponsive Hydrogels for Dermatological Applications

Most marketed HA-based dermal fillers use chemical cross-linking to improve mechanical properties and extend their lifetime in vivo; however, stiffer products with higher elasticity require an increased extrusion force for injection in clinical practice. To balance longevity and injectability, we propose a thermosensitive dermal filler, injectable as a low viscosity fluid that undergoes gelation in situ upon injection. To this end, HA was conjugated via a linker to poly(N-isopropylacrylamide) (pNIPAM), a thermosensitive polymer using "green chemistry", with water as the solvent. HA-L-pNIPAM hydrogels showed a comparatively low viscosity (G' was 105.1 and 233 for Candidate1 and Belotero Volume^®, respectively) at room temperature and spontaneously formed a stiffer gel with submicron structure at body temperature. Hydrogel formulations exhibited superior resistance against enzymatic and oxidative degradation and could be administered using a comparatively lower injection force (49 N and >100 N for Candidate 1 and Belotero Volume^®, respectively) with a 32G needle. Formulations were biocompatible (viability of L929 mouse fibroblasts was >100% and ~85% for HA-L-pNIPAM hydrogel aqueous extract and their degradation product, respectively), and offered an extended residence time (up to 72 h) at the injection site. This property could potentially be exploited to develop sustained release drug delivery systems for the management of dermatologic and systemic disorders.

Silica Hydrogels as Platform for Delivery of Hyaluronic Acid

Hyaluronic acid (HA) is chondroprotective and anti-inflammatory drug used clinically for treatment of inflammatory disorders (arthritis, skin diseases, bowel diseases, etc.). In addition, HA is a crucial ingredient in the cosmetic products used to eliminate the unpleasant consequences of inflammatory skin diseases. The main disadvantages that limit its use are its low mechanical properties and its rapid biodegradation. In this paper, silica hydrogels are considered as a promising matrix for HA to improve its properties. The hybrid HA-silica hydrogels were synthesized by the sol-gel method. Morphology of the hydrogels was investigated by optical microscopy and scanning electron microscopy methods. Taking into account their potential applications for topical and injectable delivery, much attention was paid to investigation of deformation properties of the hydrogels under shear, compression, and tension. Their resistance to enzymatic degradation in vitro was estimated. Kinetics and mechanisms of HA release from the hybrid hydrogels in vitro were also studied. It was found that the indicated properties can be controlled by synthesis conditions, HA molecular weight, and its loading in the hydrogels. Silica hydrogels are a prospective platform for the development of new soft formulations and cosmetic compositions of HA with improved pharmacological and consumer properties.

Transcriptomic Analysis in Human 3D Skin Model Injected with Resorbable Hyaluronic Acid Fillers Reveals Foreign Body Response

Usage of injectable dermal fillers applied for aesthetic purposes has extensively increased over the years. As such, the number of related adverse reactions has increased, including patients showing severe complications such as product migration, topical swelling and inflammatory reactions of the skin. In order to understand the underlying molecular events of these adverse reactions we performed a genome-wide gene expression study on the multi-cell type human Phenion® Full-Thickness Skin Model exposed to five experimental hyaluronic acid (HA) preparations with increasing cross-linking degree, four commercial fillers from Perfectha®, and non-resorbable filler Bio-Alcamid®. In addition, we evaluated whether cross-linking degree or particle size of the HA-based fillers could be associated with the occurrence of adverse effects. In all cases, exposure to different HA fillers resulted in a clearly elevated gene expression of cytokines and chemokines related to acute inflammation as part of the foreign body response. Furthermore, for one experimental filler genes of OXPHOS complexes I-V were significantly down-regulated (adjusted p-value < 0.05), resulting in mitochondrial dysfunction which can be linked to over-expression of pro-inflammatory cytokines TNFα and IL-1β and chemokine CCL2. Our hypothesis that cross-linking degree or particle size of the HA-based fillers is related to the biological responses induced by these fillers could only partially be confirmed for particle size. In conclusion, our innovative approach resulted in gene expression changes from a human 3D skin model exposed to dermal fillers that mechanistically substantiate aforementioned adverse reactions, and thereby adds to the weight of evidence that these fillers may induce inflammatory and fibrotic responses.

Evaluation of Adverse Effects of Resorbable Hyaluronic Acid Fillers: Determination of Macrophage Responses

Resorbable tissue fillers for aesthetic purposes can induce severe complications including product migration, late swelling, and inflammatory reactions. The relation between product characteristics and adverse effects is not well understood. We hypothesized that the degree of cross-linking hyaluronic acid (HA) fillers was associated with the occurrence of adverse effects. Five experimental HA preparations similar to HA fillers were synthesized with an increasing degree of cross-linking. Furthermore, a series of commercial fillers (Perfectha^®) was obtained that differ in degradation time based on the size of their particulate HA components. Cytotoxic responses and cytokine production by human THP-1-derived macrophages exposed to extracts of the evaluated resorbable HA fillers were absent to minimal. Gene expression analysis of the HA-exposed macrophages revealed the responses related to cell cycle control and immune reactivity. Our results could not confirm the hypothesis that the level of cross-linking in our experimental HA fillers or the particulate size of commercial HA fillers is related to the induced biological responses. However, the evaluation of cytokine induction and gene expression in macrophages after biomaterial exposure presents promising opportunities for the development of methods to identify cellular processes that may be predictive for biomaterial-induced responses in patients.

Hyaluronan Hydrogels: Rheology and Stability in Relation to the Type/Level of Biopolymer Chemical Modification

BDDE (1,4-butanediol-diglycidylether)-crosslinked hyaluronan (HA) hydrogels are widely used for dermo-aesthetic purposes. The rheology and stability of the gels under physiological conditions greatly affect their clinical indications and outcomes. To date, no studies investigating how these features are related to the chemistry of the polymeric network have been reported. Here, four available HA-BDDE hydrogels were studied to determine how and to what extent their rheology and stability with respect to enzymatic hydrolysis relate to the type and degree of HA structural modification. ¹H-/¹³C-NMR analyses were associated for the quantification of the “true” HA chemical derivatization level, discriminating between HA that was effectively crosslinked by BDDE, and branched HA with BDDE that was anchored on one side. The rheology was measured conventionally and during hydration in a physiological medium. Sensitivity to bovine testicular hyaluronidase was quantified. The correlation between NMR data and gel rheology/stability was evaluated. The study indicated that (1) the gels greatly differed in the amounts of branched, crosslinked, and overall modified HA, with most of the HA being branched; (2) unexpectedly, the conventionally measured rheological properties did not correlate with the chemical data; (3) the gels’ ranking in terms of rheology was greatly affected by hydration; (4) the rheology of the hydrated gels was quantitatively correlated with the amount of crosslinked HA, whereas the correlations with the total HA modification level and with the degree of branched HA were less significant; (5) increasing HA derivatization/crosslinking over 9/3 mol% did not enhance the stability with respect to hyaluronidases. These results broaden our knowledge of these gels and provide valuable information for improving their design and characterization.

Triple Cross-Linked Hyaluronic Acid Based on Tri-Hyal Technique Has More Durable Effect on Dermal Renewal

Background

Hyaluronic acid (HA)-based fillers are applied to treat facial wrinkles and volume loss. Many efforts have been made to improve properties of HA to prolong the duration in aesthetic indications. A new cross-linking technique called “Tri-Hyal”, could make HAs to achieve desired rheological characteristics. HAs synthesized by Tri-Hyal are triple cross-linked and sustained-release, which could increase duration of promoting skin rejuvenation after injection.

Purpose

To evaluate the efficiency and persistence of HAs with Tri-Hyal on skin rejuvenation and further investigate underlying mechanisms, we compared the performances of cross-linked HA (AF) based on Tri-Hyal with another highly acceptable HA filler (Res) in vivo and in vitro.

Methods

Male BALB/c mice were divided into three groups, treated with AF, Res and vehicle, respectively. Skin biopsies were taken on day 0, 30, 90 and 180 after injection and hematoxylin and eosin (H&E), Masson’s trichrome (MT), immunohistochemical (IHC) stainings for CD31, TGF-β and MMP9 were performed. EdU incorporation, cell counting kit-8 (CCK-8), SA-β-Gal staining and activity were measured by biochemical analysis. RFP-GFP-LC3 adeno virus was used for autophagic flux detection. Protein levels of CD44, P62 and LC3I/II were detected by Western blot. Reactive oxygen species (ROS) level was detected by flow cytometry with DCFH-DA probe.

Results

The AF synthesized by Tri-Hyal showed persistent dermal structural correction without attenuation up to 6 months, which was illustrated by skin thickness, formation of elastic fibers and vascular density. Consistently, in fibroblasts the AF improved cell proliferation and slowed the senescent in vitro. Furthermore, it promoted cellular autophagy to reduce ROS level, which would account for its function in skin renewal.

Conclusion

The HA with Tri-Hyal could stimulate the production of extracellular matrix components more persistently than traditional HA fillers. In terms of mechanisms, it delayed senescence in dermal fibroblasts through reducing oxidative stress mediated by induction of autophagy.

An evaluation of the long-term safety and biodegradability of hyaluronic acid dermal fillers (YVOIRE® ) for the correction of nasolabial folds: Two multicenter, prospective, observational cohort studies

BACKGROUND

The therapeutic effects of hyaluronic acid dermal fillers to correct facial wrinkles and folds usually last up to 6-12 months. Few studies have evaluated their long-term safety.

AIMS

To evaluate the long-term safety and biodegradability of two hyaluronic acid dermal fillers (YVOIRE^® classic s and YVOIRE^® volume s) for the correction of nasolabial folds (NLFs) in two prospective, observational studies.

METHODS

Subjects scheduled to receive the injections of YVOIRE^® classic s (N = 503) or YVOIRE^® volume s (N = 503) at NLFs were followed up until complete clinical biodegradation, defined as a change in Wrinkle Severity Rating Scale (WSRS) score of ≥0 from baseline. The primary biodegradation endpoint was the proportion of subjects with complete clinical biodegradation during or after the 104-week post-treatment period.

RESULTS

Complete clinical biodegradation was observed in 93.5% [95% CI 91.0-95.5%] of 494 assessable YVOIRE^® classic s recipients and 98.5% [95% CI 97.0-99.4%] of 469 YVOIRE^® volume s recipients during the 104-week post-treatment period. In most subjects, complete clinical biodegradation was observed within 52 weeks of the last treatment. Treatment-related adverse events (AEs) (mostly mild local injection-site reactions) occurred within 52 weeks post-treatment, in 68.2% and 75.0% of YVOIRE^® classic s and YVOIRE^® volume s recipients, respectively. During the 12- to 18-months after YVOIRE^® volume s injection, 0.6% of subjects had treatment-related AEs (local injection-site reactions). No treatment-related AEs occurred 12- to 24-months after YVOIRE^® classic s injection.

CONCLUSIONS

YVOIRE^® classic s and YVOIRE^® volume s can be safely used to correct NLFs. Total clinical biodegradation tends to occur within 12 months of injection.

Effects of Polynucleotide Dermal Filler in the Correction of Crow's Feet Using an Antera Three-Dimensional Camera

BACKGROUND

Dermal fillers are gaining interest for tissue enlargement and skin improvement. Among them, polynucleotides have demonstrated multiple skin beneficial effects. The effects of polynucleotide fillers were objectively evaluated using an Antera 3D camera, subjectively evaluated by participants and investigators.

METHODS

Thirty subjects with crow's feet were enrolled in the study. The subjects received polynucleotide filler for crow's feet. Crow's feet grading score (CFGS), global esthetic improvement scale (GAIS), and Antera 3D imaging results were evaluated.

RESULTS

Twenty-eight subjects (93.3%) completed the study. An improvement in CFGS compared with that at baseline (p < 0.001) was observed 18 weeks after the first injection of polynucleotides. Additionally, at the final visit, there were improvements in wrinkle, texture, pore, depression, and Hb values compared with those at baseline (p < 0.05). However, no significant difference in melanin level was detected between the initial and final visits.

CONCLUSIONS

Improvements in wrinkles, pores, texture, depression, and Hb level after polynucleotide filler injection were verified by objective and subjective evaluations. To the best of our knowledge, this is the first report on the objective evaluation of polynucleotide fillers in crow's feet using the Antera 3D camera.

LEVEL OF EVIDENCE IV

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Molecular Weight of Hyaluronic Acid Has Major Influence on Its Efficacy and Safety for Viscosupplementation in Hip Osteoarthritis: A Systematic Review and Meta-Analysis

BACKGROUND

This study aimed to compare the efficacy and safety of intra-articular hyaluronic acid (HA) injection with different molecular weights (MWs) for treating hip osteoarthritis (OA).

METHODS

A systematic literature search for relevant studies was conducted in 3 electronic databases, including PubMed, BMJ Journals, and Cochrane Library, from inception to April 2020. Extracted outcomes included visual analogue scale (VAS) (1, 3, and 6 months), Lequesne index (3 and 6 months), and adverse effects. HAs were classified into low-molecular-weight (LMW), moderate-molecular-weight (MMW), high-molecular-weight (HMW), and ultra-high-molecular-weight (UHMW) groups. Meta-analysis was performed using Review Manager 5.3.

RESULTS

A total of 15 studies with 614 patients were included. Our meta-analysis showed that the HMW HA group had the best improvement in VAS and Lequesne index compared with other HA groups for all the follow-up visits. Moreover, the HMW group demonstrated significantly better improvement than the other groups in VAS at 6-month follow-up and in Lequesne index at 3- and 6-month follow-ups. Analysis for adverse effects revealed low rates of systemic adverse effects (≤0.6%) in all groups and similar rate of local adverse effects (around 10%) among the groups except for UHMW HA group (37.5%).

CONCLUSION

Among different MWs of HA for treating hip OA, HMW HA injection demonstrated the best efficacy for up to 6 months after treatment without increased risk of adverse effects. Further studies with more comprehensive data and a higher level of evidence are required to prove our results.

ASIA syndrome symptoms induced by gluteal biopolymer injections: Case-series and narrative review

Background

The number of plastic surgery procedures have been rising in the last few years. The morbi-mortality due to illegal use of biopolymers is a public health problem. One of the clinical consequences, foreign body modelling reaction, may be a precursor of ASIA (Autoimmune/Inflammatory disease induced by adjuvants) syndrome.The objective of this article is to present a case-series study of patients who developed ASIA syndrome following gluteal injection with biopolymers and emphasize the importance of toxic exposure in triggering autoimmune responses. A surgical technique used on some of the patients in the study is described.

Methods

A group of thirteen patients, diagnosed with foreign body modelling reaction, who developed ASIA syndrome confirmed by approved criteria was followed between May 2016 and May 2018. The "Butterfly Wings Technique," a new surgical procedure for patients who have medium to severe compromise, was used on five of them.A narrative literature review was done to look for subjects with ASIA syndrome and gluteal biopolymer infiltration.

Results

All the patients in the present case-series with foreign body modelling reaction developed ASIA syndrome. Some of them had a background of familial autoimmunity. Five of the patients were surgically treated and saw a clinical improvement after the extraction of the biopolymer with the proposed technique.The narrative literature review identified 7 articles related to the disease through the database search.

Conclusions

We suggest that foreign body modelling reaction should be considered a precursor to ASIA syndrome. New research projects will be needed in the future to evaluate the factors that determine when ASIA syndrome is triggered in a patient with this reaction.

Two Randomized Controlled Trials of Hyaluronic Acid Fillers for the Correction of Nasolabial Folds

YVOIRE Classic s (YC) and Restylane (RES) have similar rheological properties, which suit mid-dermis injection, while the rheological properties of YVOIRE Volume s (YV) are comparable to those of Perlane (PER), which suit deep dermis injection to treat deep wrinkles. Two similarly designed studies aimed to evaluate the performance and safety of YC and YV injected into the nasolabial folds (NLFs).

METHODS

These were split-face designed, evaluator-blind, noninferiority studies. Fifty-eight subjects with moderate-to-severe NLFs were enrolled in the first study and treated with YC and RES, and 57 subjects were enrolled in the second study and treated with YV and PER. The Wrinkle Severity Rating Scale ranged from 1 (no visible fold) to 5 (extremely deep and long folds), and subject satisfaction was evaluated.

RESULTS

The least squares mean Wrinkle Severity Rating Scale scores (standard error) at week 26 were 2.56 (0.09) for both YC- and RES-treated NLFs and 2.89 (0.08) and 2.91 (0.08) for YV- and PER-treated NLFs, respectively. The difference between the groups was 0 and 0.02, and the lower limit of its 95% confidence interval was -0.0725 and -0.0125, which was greater than the predefined margin (-0.29), proving the noninferiority of YC and YV to RES and PER, respectively. The safety profiles and subject satisfaction of YC and YV were similar to those of RES and PER, respectively.

CONCLUSION

YC is comparable to RES and YV is comparable to PER in terms of performance and safety profiles, with NLF-correcting effects lasting for up to 26 weeks.

Extracellular Matrix Mimics Using Hyaluronan-Based Biomaterials

Hyaluronan (HA) is a critical element of the extracellular matrix (ECM). The regulated synthesis and degradation of HA modulates the ECM chemical and physical properties that, in turn, influence cellular behavior. HA triggers signaling pathways associated with the adhesion, proliferation, migration, and differentiation of cells, mediated by its interaction with specific cellular receptors or by tuning the mechanical properties of the ECM. This review summarizes the recent advances on strategies used to mimic the HA present in the ECM to study healthy or pathological cellular behavior. This includes the development of HA-based 2D and 3D in vitro tissue models for the seeding and encapsulation of cells, respectively, and HA particles as carriers for the targeted delivery of therapeutic agents.

Comparative Evaluation of the Effectiveness of Novel Hyaluronic Acid-Polynucleotide Complex Dermal Filler

HA (Hyaluronic acid) filler, the most commonly used dermal filler, causes several side effects. HA-PN (Hyaluronic acid-Polynucleotide), a new composite filler, has excellent biocompatibility and induces tissue regeneration. In this study, we compare the efficacies and safety profiles of these fillers. The characteristics of HA and HA-PN fillers were compared using scanning electron microscopy and rheometry. No morphological difference was noted between the fillers. However, the latter had higher viscosity and elasticity values. The HA-PN filler induced higher cell migration than the HA filler in a wound healing assay. It was also found to stimulate better collagen synthesis in human and mouse fibroblasts. The HA and HA-PN fillers were injected into SKH1 hairless mice to determine changes in their volume for up to 24 weeks. Increased cell migration and collagen synthesis were observed in mice injected with the HA-PN complex filler. Although the safety and durability of the HA and HA-PN fillers were similar, the latter induced a lower transient receptor potential vanilloid 4 expression and caused less stimulation upon injection. In conclusion, HA-PN complex fillers can stimulate fibroblast growth and facilitate volume growth and skin regeneration.

Benchtop NMR spectroscopy in the analysis of substandard and falsified medicines as well as illegal drugs

Substandard and falsified medical products may cause harm to patients and fail to treat the diseases or conditions for which they were intended. It is therefore required to have analytical methods available to assess medical product quality. Benchtop NMR spectroscopy provides a generic, inherently quantitative, analytical method capable of separating specific signals from those of a matrix. We have developed an analytical method for the analysis of active ingredients in pharmaceutical products and illegal drugs, based on benchtop NMR spectroscopy. Within its resolution limits, benchtop NMR spectroscopy is useful in determining the identity of the active ingredients in products containing acetaminophen, aspirin, caffeine, diclofenac, ibuprofen, naproxen, sildenafil, tadalafil and sibutramine, cocaine, and gamma hydroxybutyric acid, with a limit of detection of about 1 mg/mL. Furthermore, the content of the active ingredient can be determined with an error of 10%. Additionally, a chemometrics approach is shown to be useful to classify spectra in order to identify the active substances present in the sample, reducing the need for expert interpretation of the spectra acquired.