Current Practices in Hyaluronic Acid Dermal Filler Treatment in Asia Pacific and Practical Approaches to Achieving Safe and Natural-Looking Results

Late-Onset Reactions after Hyaluronic Acid Dermal Fillers: A Consensus Recommendation on Etiology, Prevention and Management

Hyaluronic acid (HA) dermal fillers, generally considered low-risk, can lead to rare late-onset reactions (LORs) manifesting between 3 and 4 months postinjection, occasionally even as early as 24 h postinjection. The Complication Assessment and Risk Evaluation (CARE) board was established to review these reactions. In this publication, the authors aims to explore the etiological hypotheses underlying LORs, associated risk factors, prevention, and management approaches suggested by the CARE board. The CARE board identified three etiological hypotheses contributing to LORs. Firstly, the physicochemical structure of the filler, particularly low molecular weight HA, which may trigger an immune response. Secondly, infection, potentially introduced during injection or by dormant biofilm activation. Lastly, an imbalance in the host immune system, caused by factors like autoimmune diseases or viral infections, may lead to extended foreign body reactions, delayed type IV hypersensitivity, or adjuvant-based reactions. Based on these hypotheses, the board categorized various risk factors as patient-related (e.g., recent dental treatment, current medical status, active autoimmune disease), product-related (e.g., molecular weight), and procedure-related (e.g., aseptic technique and trauma). To reduce the risk of LORs, the CARE board recommends diligent patient selection, including comprehensive medical history assessment and informed consent. Practitioners should maintain an effective aseptic technique, and choose an appropriate product and injection depth for the anatomical location. Post-procedure, patients should receive education on proper filler care. Management of LORs depends on the suspected etiology, and the CARE board has proposed an algorithm to determine the most appropriate treatment. Hyaluronidase is recommended for noninflammatory reactions in the absence of active infection, while watchful waiting and/or steroid treatment may be preferred for inflammatory reactions. Hyaluronidase is not recommended as a first-line treatment for infections, which require drainage, bacterial culture, and antibiotic treatment. However, the board emphasizes the need for individualized evaluation and treatment in all cases.

Ellansé: Advanced Technology and Advantageous Selection of New Collagen Stimulating Agents for Face Rejuvenation

Facial injections have a comparative mature market and system in China, but all kinds of injection materials have their own advantages and disadvantages, even hyaluronic acid, as the most common injection material, can form an unnatural stiffness after injection. Currently, Ellansé, a biodegradable collagen stimulator, has shown superior aesthetic results while ensuring safety and naturalness, making it a more preferable choice for a variety of facial injections. The purpose of this review is to introduce the features and benefits of Ellansé, so that doctors in the field can better understand and learn how to use it properly and minimize the risk of complications, and have a better choice for the medical aesthetic field in China in numerous aspects. The papers with the keyword "Ellansé" is very few in number, and there is a lack of systematic overview. Ellansé itself has unique advantages for the Chinese population, as it is an attractive option for the treatment of aging face due to high patient satisfaction, long-lasting results and low side effects (Guo et al. in J Cosmet Dermatol 21(5):1959-1966, 2022). More clinical data will be available in the future to confirm its performance and longevity in various sites. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Etiology of Delayed Inflammatory Reaction Induced by Hyaluronic Acid Filler

The etiology and pathophysiology of delayed inflammatory reactions caused by hyaluronic acid fillers have not yet been elucidated. Previous studies have suggested that the etiology can be attributed to the hyaluronic acid filler itself, patient's immunological status, infection, and injection technique. Hyaluronic acid fillers are composed of high-molecular weight hyaluronic acids that are chemically cross-linked using substances such as 1,4-butanediol diglycidyl ether (BDDE). The mechanism by which BDDE cross-links the two hyaluronic acid disaccharides is still unclear and it may exist as a fully reacted cross-linker, pendant cross-linker, deactivated cross-linker, and residual cross-linker. The hyaluronic acid filler also contains impurities such as silicone oil and aluminum during the manufacturing process. Impurities can induce a foreign body reaction when the hyaluronic acid filler is injected into the body. Aseptic hyaluronic acid filler injections should be performed while considering the possibility of biofilm formation or delayed inflammatory reaction. Delayed inflammatory reactions tend to occur when patients experience flu-like illnesses; thus, the patient's immunological status plays an important role in delayed inflammatory reactions. Large-bolus hyaluronic acid filler injections can induce foreign body reactions and carry a relatively high risk of granuloma formation.

Ultra-condensed Fat: A Novel Fat Product for Volume Augmentation

BACKGROUND

Fat transplantation retention rate is individualized and unpredictable. The presence of blood components and oil droplets in the injected lipoaspirate increases inflammation and fibrosis in a dose-dependent manner, and is probably the key factor associated with poor retention.

OBJECTIVES

This study describes a volumetric fat grafting strategy based on optimization of grafts via screening intact fat particles and absorbing free oil droplets and impurities.

METHODS

Centrifuged fat components were analyzed by n-hexane leaching. A special device was applied to de-oil intact fat components and obtain ultra-condensed fat (UCF). UCF was evaluated by scanning electron microscopy, particle size analysis, and flow cytometric analysis. Histological and immunohistochemical changes were investigated in a nude mouse fat graft model over 90 days.

RESULTS

The lower 50% of centrifuged fat was concentrated to 40% of the original volume to obtain UCF. In UCF, the free oil droplet content was less than 10%, more than 80% of particles were larger than 1000 µm, and architecturally important fat components were present. The retention rate of UCF was significantly higher than that of Coleman fat on day 90 (57.5 ± 2.7% vs. 32.8 ± 2.5%, p < 0.001). Histological analysis detected small preadipocytes with multiple intracellular lipid droplets on day 3 in UCF grafts, indicative of early adipogenesis. Angiogenesis and macrophage infiltration were observed in UCF grafts soon after transplantation.

CONCLUSION

Adipose regeneration with UCF involves rapid macrophage infiltration and exit, resulting in angiogenesis and adipogenesis. UCF may serve as a lipofiller which is beneficial for fat regeneration.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .