Human Histology and Persistence of Various Injectable Filler Substances for Soft Tissue Augmentation

Clinical Outcomes and Safety Profile of a Dextranomer-Hyaluronic Acid Hybrid Filler: A Case Series Analysis

BACKGROUND

The demand for aesthetic treatments targeting the middle and lower face is on the rise, especially because of changes in appearance associated with aging.

AIM

This study aimed to assess the use of a hybrid filler for sculpting and contouring of the chin, jaw, and malar region.

METHODS AND MATERIALS

A retrospective analysis was performed on patients who underwent jaw and chin contouring and cheek augmentation using a hybrid filler (hyaluronic acid and dextranomer). The evaluation focused on the naturalness of appearance, enhancement in volume, and the durability of the results, employing a 5-point scale. Both patient satisfaction and physician evaluations were measured using the Likert scale and the Global Aesthetic Improvement Scale (GAIS), respectively. Follow-up with patients extended up to 6 months after treatment, during which any treatment-related adverse events (AEs) were meticulously recorded and analyzed.

RESULTS

Nineteen patients participated in the study, receiving an average injection volume of 2.4 ± 0.9 mL to attain the desired outcomes. The evaluation of natural appearance, volumizing effects, and durability at the analyzed time point consistently scored above 4. All 19 patients' aesthetic improvement was evaluated as "very much improved" and "much improved", at the GAIS score. All patients report improvement in their appearance, with 89.5% rating it as "very much improved" or "much improved" on the Likert scale. Only expected AEs such as mild pain and lower swelling were registered.

CONCLUSION

The hybrid filler proved effective and safe for facial contouring, with significant patient satisfaction and minimal adverse effects.

Polylactic Acid-Based Polymers Used for Facial Rejuvenation: A Narrative Review

For decades, a diverse range of natural and synthetic materials have been utilized to enhance human tissue and achieve improved aesthetic results. Among these, dermal fillers are some of the most popular treatments. Initially, the primary role of dermal fillers was to restore lost volume. However, with advancements in biomaterial research, a variety of biostimulatory fillers have become essential in aesthetic medicine. One such filler, polylactic acid (PLA), has been extensively used for facial rejuvenation. Upon injection, PLA not only provides immediate volume restoration but also enhances skin quality and appearance while promoting the regeneration of collagen, elastin, and vasculature. This narrative review highlights PLA as a regenerative aesthetic treatment, detailing its physicochemical properties, mechanisms of regeneration stimulation, and clinical applications in facial aesthetics. It represents the cutting-edge foundation upon which further developments can be built to ensure optimal and safe outcomes in treatments using PLA-based collagen stimulators and other similar products for facial rejuvenation. 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 .

Tofacitinib for managing granuloma formation after dermal filler injection: three case reports and literature review

BACKGROUND

Granuloma formation is an uncommon and persistent skin inflammatory condition caused by the injection of dermal fillers. The exact cause of this reaction is not well understood, but it may be associated with irritating components or abnormal immune function. Treating granulomas can be difficult. However, recent research has shown that Janus kinase (JAK) inhibitors hold promise as a potential therapy for refractory granulomatous diseases.

OBJECTIVES

The aim was to evaluate the efficacy and safety of tofacitinib as a treatment for granulomas secondary to filler injection and the possible mechanisms were discussed and summarized.

METHODS

This study focuses on three cases of patients who experienced granuloma formation after receiving filler injections and were subsequently treated with tofacitinib. The efficacy and safety of the treatment were evaluated using parameters such as photographs and monitoring for any adverse reactions. In addition, a literature review was conducted to explore the underlying mechanisms and potential effects of tofacitinib.

RESULTS

All three cases recovered from swelling and nodules without side effects through the off-label use of oral tofacitinib. Existing data review reveals some approaches for cutaneous granulomatous disorders like inhibiting macrophage activation and downregulation of the JAK-STAT pathway.

CONCLUSION

This report emphasizes the effectiveness of JAK inhibitors in treating granulomas caused by filler injections. Recent advancements in understanding the underlying mechanisms of granulomatous reactions have paved the way for JAK inhibitors to be regarded as a promising treatment choice. However, further research is necessary to fully assess the safety and long-term effectiveness of using tofacitinib for granuloma treatment.

Application of PLLA (Poly-L-Lactic acid) for rejuvenation and reproduction of facial cutaneous tissue in aesthetics: A review

Poly-L-lactin acid (PLLA) has been widely used in the field of bio-medicine. In 2004, as an injectable material, PLLA was approved by the FDA to treat AIDS-related facial atrophy. Since then, several injectable stuffs containing PLLA have been approved for marketing in various countries and regions. Recently, PLLA has often been used to treat facial rejuvenation problems like cutaneous depressions and static wrinkles which always induce unsatisfactory facial expression. This review introduces the physicochemical properties, regeneration stimulating mechanism, applications in aesthetics and injectable comorbidity of PLLA.

The Role of Calcium Hydroxylapatite (Radiesse) as a Regenerative Aesthetic Treatment: A Narrative Review

For decades, a wide variety of natural and synthetic materials have been used to augment human tissue to improve aesthetic outcomes. Dermal fillers are some of the most widely used aesthetic treatments throughout the body. Initially, the primary function of dermal fillers was to restore depleted volume. As biomaterial research has advanced, however, a variety of biostimulatory fillers have become staples in aesthetic medicine. Such fillers often contain a carrying vehicle and a biostimulatory material that induces de novo synthesis of major structural components of the extracellular matrix. One such filler, Radiesse (Merz Aesthetics, Raleigh, NC), is composed of calcium hydroxylapatite microspheres suspended in a carboxymethylcellulose gel. In addition to immediate volumization, Radiesse treatment results in increases of collagen, elastin, vasculature, proteoglycans, and fibroblast populations via a cell-biomaterial-mediated interaction. When injected, Radiesse acts as a cell scaffold and clinically manifests as immediate restoration of depleted volume, improvements in skin quality and appearance, and regeneration of endogenous extracellular matrices. This narrative review contextualizes Radiesse as a regenerative aesthetic treatment, summarizes its unique use cases, reviews its rheological, material, and regenerative properties, and hypothesizes future combination treatments in the age of regenerative aesthetics.

LEVEL OF EVIDENCE: 5

Investigation of Crosslinking Parameters and Characterization of Hyaluronic Acid Dermal Fillers: From Design to Product Performances

Despite process similarities, distinctive manufacturing technologies offer hyaluronic acid dermal fillers with different in vitro physicochemical and rheological properties due to peculiar crosslinked hydrogel networks. A better understanding of dermal filler properties could provide specific clinical indications and expectations with more accurate performance correlations. In this study, with an emphasis on the degree of modification, hyaluronic acid concentration and molecular weight, these process parameters were able to modulate dermal filler properties, especially rheology. Moreover, an extensive characterization of commercial hyaluronic acid injectables of the Hyal System line was described to present product properties and help to elucidate related clinical effects. Standardized methodologies were applied to correlate in vitro parameters with feasible clinical indications. In view of an optimized dermal filler design, the results of the extrudability measurements allowed the quantification of the effect of hydrogel composition, rheological properties and needle size on injectability. Composition, dynamic viscosity and needle size showed an impactful influence on hydrogel extrudability. Finally, the positive influence of 200 KDa hyaluronic acid in comparison to fragments of ether-crosslinked hyaluronic acid on fibroblast recognition were shown with a migration assay.

Widening Aging Eyes and Ending Outdoor Tearing with Retrobulbar Injections of Dermal Fillers

As people age, the intraorbital fat may diminish and palpebral fissures may narrow, causing the eyes to increasingly tear outside in cold weather. As the bulbus recedes from the conjunctiva, a "wind trap" is formed in the lateral corner of the eye. This wind trap appears to irritate the adjacent lacrimal gland. In this article, an 84-year-old patient experienced annoying outdoor tearing despite having undergone three tarsal strip canthopexies during the past 20 years.

Methods

Retrobulbar injections of 3.5-mL high-viscous dermal fillers (Bellafill or Radiesse) pushed the eyeballs forward, aligned the bulbus with the conjunctiva, and closed the wind trap behind the lateral canthus. Magnetic resonance imaging confirmed the filler material in the posterior lateral corner of the orbit.

Results

The effect was immediate: the patient's constant outdoor tearing had resolved after the first treatment of his senile enophthalmos. In addition, the narrow palpebral fissure had widened by 2 mm and rejuvenated his aging eyes.

Conclusions

An eyeball that has receded with age can be pushed forward with a retrobulbar injection of a long lasting dermal filler to reattach to the eyelids.

The extended effect of adsorbed damage-associated molecular patterns and Toll-like receptor 2 signaling on macrophage-material interactions

Implanted biomaterials elicit an immune-mediated foreign body reaction (FBR) that results in the fibrous encapsulation of the implant and can critically impact the performance of some implants. Consequently, understanding the molecular mechanisms that underpin cell-materials interactions that initiate biomaterial-induced inflammation and fibrosis is critical to improving the performance of biomaterial implants negatively impacted by the FBR. Damage-associated molecular patterns (DAMPs) are endogenous mediators of inflammation that are released upon tissue injury and induce sterile inflammation via Toll-like receptors (TLRs). However, the prevalence of DAMPs within the adsorbed protein layer on material surfaces and their role mediating cell-material interactions is unclear. Previously, our group demonstrated that molecules in fibroblast lysates adsorbed to various biomaterials and induced a potent TLR2-dependent inflammatory response in macrophages at 24 h. In this study, we examined the extended response of RAW-Blue reporter macrophages on lysate or serum-adsorbed Teflon™ AF surfaces to understand the potential role of adsorbed DAMPs in macrophage-material interactions at later time points. Lysate-conditioned surfaces maintained increased nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1) transcription factor activity and increased expression Regulated upon Activation, Normal T Cell Expressed and Presumably Secreted (RANTES/CCL5) at 72 h and 120 h, compared to FBS-conditioned surfaces. In contrast, monocyte chemoattractant protein 1 (MCP-1/CCL2) was only elevated at 72 h in lysate conditions. Transforming growth factor beta 1 (TGF-β1) secretion was significantly increased on lysate-conditioned surfaces, while conditioned media from macrophages on lysate-conditioned surfaces induced alpha smooth muscle actin (αSMA) expression in 3T3 fibroblasts. TLR2 neutralizing antibody treatment significantly decreased NF-κB/AP-1 activity and attenuated TGF-β1 expression at both time points, and MCP-1 and RANTES at 72 h. Finally, multinucleated cells were observed on lysate-conditioned surfaces at 72 h, indicating adsorbed DAMPs induced a fusion permissive environment for adherent macrophages. This study demonstrates that adsorbed DAMPs continue to influence macrophage-material responses beyond the initial 24-h period and maintain a pro-inflammatory and fibrotic response that models aspects of the early FBR. Furthermore, the transient inhibition of TLR2 continued to exert an effect at these later time points, suggesting TLR2 may be a target for therapeutic interventions in FBR.

Bringing hydrogel-based craniofacial therapies to the clinic

This review explores the evolution of the use of hydrogels for craniofacial soft tissue engineering, ranging in complexity from acellular injectable fillers to fabricated, cell-laden constructs with complex compositions and architectures. Addressing both in situ and ex vivo approaches, tissue restoration secondary to trauma or tumor resection is discussed. Beginning with relatively simple epithelia of oral mucosa and gingiva, then moving to more functional units like vocal cords or soft tissues with multilayer branched structures, such as salivary glands, various approaches are presented toward the design of function-driven architectures, inspired by native tissue organization. Multiple tissue replacement paradigms are presented here, including the application of hydrogels as structural materials and as delivery platforms for cells and/or therapeutics. A practical hierarchy is proposed for hydrogel systems in craniofacial applications, based on their material and cellular complexity, spatial order, and biological cargo(s). This hierarchy reflects the regulatory complexity dictated by the Food and Drug Administration (FDA) in the United States prior to commercialization of these systems for use in humans. The wide array of available biofabrication methods, ranging from simple syringe extrusion of a biomaterial to light-based spatial patterning for complex architectures, is considered within the history of FDA-approved commercial therapies. Lastly, the review assesses the impact of these regulatory pathways on the translational potential of promising pre-clinical technologies for craniofacial applications. STATEMENT OF SIGNIFICANCE: While many commercially available hydrogel-based products are in use for the craniofacial region, most are simple formulations that either are applied topically or injected into tissue for aesthetic purposes. The academic literature previews many exciting applications that harness the versatility of hydrogels for craniofacial soft tissue engineering. One of the most exciting developments in the field is the emergence of advanced biofabrication methods to design complex hydrogel systems that can promote the functional or structural repair of tissues. To date, no clinically available hydrogel-based therapy takes full advantage of current pre-clinical advances. This review surveys the increasing complexity of the current landscape of available clinical therapies and presents a framework for future expanded use of hydrogels with an eye toward translatability and U.S. regulatory approval for craniofacial applications.

Injectable polydimethylsiloxane microfiller coated with zwitterionic polymer for enhanced biocompatibility

Silicone-based fillers have been applied in several branches of medicine, such as soft tissue augmentation, because of their stability and durability. However, the inherently hydrophobic surfaces of silicone occasionally cause excessive deposition of the fibrous matrix in vivo, leading to severe fibrosis. In this study, we evaluated the use of a zwitterionic copolymer to offer a facile surface treatment method for silicone-based fillers and performed a preclinical trial of the formulation as-prepared. The copolymer has amphiphilic moieties, which act as macromolecular surfactants that can functionalize and stabilize the silicone particles during fabrication. The effectiveness and safety of the particle filler were evaluated histologically by scoring the peri-implant tissues into previously defined categories. Our results suggest that zwitterion-coated silicone fillers can inhibit protein adsorption, and thus, help attenuate foreign body reactions in a rat model. This demonstrates their potential for wide application in different fields within the discipline of medicine.

Materials Selection for the Injection into Vaginal Wall for Treatment of Vaginal Atrophy

Vaginal atrophy caused by the aging process and perineal trauma has a negative impact on women. A new vaginal atrophy treatment is injection of materials into the vaginal wall, including platelet-rich plasma (PRP), autogenous fat graft (AFG), hyaluronic acid (HA), botulinum toxin (BTX), and collagen, but to date their efficacy has not been reviewed. Vaginal wall injection is available only for mild cases of vaginal atrophy or as an adjunct to vaginal surgery. PRP is used mainly to restore vaginal function, and multiple injections are needed to achieve good results in vaginal atrophy. HA, AFG, and collagen are used mainly to augment the vaginal wall. BTX injection can inhibit vaginal muscle spasm and reduce pain during sexual intercourse in patients with vaginismus. Injection of most of these materials into vaginal wall is effective and relatively safe. Vascular embolisms are the most serious complication of vaginal injection and should be prevented. In addition, there has been no randomized double-blind placebo-controlled trial or discussion of methods to avoid serious complications resulting from vaginal injection. Therefore, further studies of the injection of materials into the vaginal wall to treat vaginal atrophy are required, and the procedures should be standardized to benefit more patients.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 www.springer.com/00266 .

Immunocompatibility and non-thrombogenicity of gelatin-based hydrogels

Immunocompatibility and non-thrombogenicity are important requirements for biomedical applications such as vascular grafts. Here, gelatin-based hydrogels formed by reaction of porcine gelatin with increasing amounts of lysine diisocyanate ethyl ester were investigated in vitro in this regard. In addition, potential adverse effects of the hydrogels were determined using the "Hen's egg test on chorioallantoic membrane" (HET-CAM) test and a mouse model.The study revealed that the hydrogels were immunocompatible, since complement activation was absent and a substantial induction of reactive oxygen species generating monocytes and neutrophils could not be observed in whole human blood. The density as well as the activation state of adherent thrombocytes was comparable to medical grade polydimethylsiloxane, which was used as reference material. The HET-CAM test confirmed the compatibility of the hydrogels with vessel functionality since no bleedings, thrombotic events, or vessel destructions were observed. Only for the samples synthesized with the highest LDI amount the number of growing blood vessels in the CAM was comparable to controls and significantly higher than for the softer materials. Implantation into mice showed the absence of adverse or toxic effects in spleen, liver, or kidney, and only a mild lymphocytic activation in the form of a follicular hyperplasia in draining lymph nodes (slightly increased after the implantation of the material prepared with the lowest LDI content). These results imply that candidate materials prepared with mid to high amounts of LDI are suitable for the coating of the blood contacting surface of cardiovascular implants.

Complications Following Non-Surgical Aesthetic Treatments in HIV+ Patients Receiving Antiretroviral Therapy: A 12-Years Experience

Since the advent of HIV antiretroviral therapies at the end of the 20th century, the morbidity and mortality rates associated with HIV infection have decreased dramatically. Unfortunately, these benefits are associated with substantial morphologic changes in the body, such as abnormal fat distribution with peripheral lipohypertrophy and facial lipoatrophy. Facial wasting is considered the major stigma for HIV–infected people and may result in reduced antiretroviral adherence. Patients suffering from the stigmata of HIV infection can benefit from non-surgical aesthetic treatments performed with fillers or lipolytic agents that provide a quick and reliable service for facial rejuvenation, with high patient satisfaction and a low risk of complications. In the present paper, a retrospective analysis of complications following non-surgical aesthetic treatments (calcium hydroxyapatite-based filler, hyaluronic acid filler, polyacrylamide hydrogel filler and dehoxycholic acid injections), in a cohort of 116 consecutive HIV+ patients, treated over a period of 12 years, was performed. With the exception of the tardive swelling reported after calcium hydroxyapatite injections, complications were recorded just after polyacrylamide hydrogel treatment as small, palpable, nonvisible nodules or aseptic abscess. Our experience is consistent with those already published in the literature and the complication rate seems to be comparable to non-infected patients.

Objective evaluation of biomaterial effects after injection laryngoplasty - Introduction of artificial intelligence-based ultrasonic image analysis

OBJECTIVE

Hyaluronic acid (HA) can be degraded over time. However, persistence of the effects after injection laryngoplasty (IL) for unilateral vocal fold paralysis (UVFP), longer than expected from HA longevity, has been observed. The purpose of the study was to develop a methodology with clinical utility for objective evaluation of the temporal change in HA volume after IL using artificial intelligence (AI)-based ultrasonic assessment.

DESIGN, SETTING AND PARTICIPANTS

Imaging phantoms simulating injected HA were built in different volumes for designing the algorithm for machine learning. Subsequently, five adult patients who had undergone IL with HA for UVFP were recruited for clinical evaluation.

MAIN OUTCOME MEASURES

Estimated volumes were evaluated for injected HA by the automatic algorithm as well as voice outcomes at 2 weeks, and 2 and 6 months after IL.

RESULTS

On imaging phantoms, contours on each frame were described well by the algorithm and the volume could be estimated accordingly. The error rates were 0%-9.2%. Moreover, the resultant contours of the HA area were captured in detail for all participants. The estimated volume decreased to an average of 65.76% remaining at 2 months and to a minimal amount at 6 months while glottal closure remained improved.

CONCLUSION

The volume change of the injected HA over time for an individual was estimated non-invasively by AI-based ultrasonic image analysis. The prolonged effect after treatment, longer than HA longevity, was demonstrated objectively for the first time. The information is beneficial to achieve optimal cost-effectiveness of IL and improve the life quality of the patients.