Human histology and persistence of various injectable filler substances for soft tissue augmentation

Clinical and Histological Effects of Calcium Hydroxyapatite Filler in the Orofacial Region: A Study in Rats

BACKGROUND

Calcium hydroxyapatite (CaHA) dermal filler has been increasingly used in facial aesthetic procedures.

OBJECTIVE

To investigate clinical and histological changes associated with calcium hydroxyapatite (CaHA) dermal filler in the orofacial region.

MATERIALS AND METHODS

Forty-eight female Wistar rats were divided into CaHA and control groups. The material was applied in the ventral tongue and the submandibular region; the animals were euthanized after 7, 30, and 90 days.

RESULTS

After 7 days, yellowish nodules with a firm consistency were observed on the tongue. In 2 animals, the material migrated to the base of the tongue. Histopathological examination revealed CaHA spheres surrounded by an infiltrate, predominantly composed of macrophages. In the CaHA group, the percentage of collagen in the tongue and dermis was higher compared with the control group (p < .05) at both 30 and 90 days. The thickness of the epidermis/dermis was also higher in the CaHA group (p < .05). In 5 submandibular glands containing material, areas of edema and hyperemia were observed, along with infiltrates of neutrophils, lymphocytes, and plasma cells. Changes in the morphology of ducts and acini in adjacent regions were evident.

CONCLUSION

CaHA exhibits satisfactory properties for filling and collagen biostimulation in the tested regions. Further studies are required to explore the potential for migration and the glandular alterations.

One-Year Safety Evaluation of New Hyaluronic Acid Fillers (YYS Series): A Prospective, Multicenter, Observational Study

BACKGROUND

With the continuous increasing availability of new filler products, each hyaluronic acid filler brand has distinctive pharmacokinetics, which may be associated with different complications. Therefore, the long-term safety of new generations of fillers should be evaluated.

OBJECTIVE

This prospective, multicenter, observational, postmarketing study (ClinicalTrials.gov identifier: NCT04738019) aimed to investigate the incidence of delayed-onset nodules and adverse reactions after the injection of new hyaluronic acid fillers (YYS series) into the facial skin.

METHODS

Subjects scheduled to receive an injection YYS series filler were followed up for 52 weeks. The authors aimed to determine the incidence of a self-reported delayed-onset nodule-a visible or palpable nodule or mass at the injection site that was detected beyond the 14th day following the injection-during the 1-year follow-up period.

RESULTS

Among the 1,022 subjects who received an injection of the YYS series, the incidences of delayed-onset nodules were 0% for YYS 360, YYS 540, and YYS 720. A 0.21% incidence (1 delayed hypersensitivity reaction) of a delayed-onset adverse reaction was noted for YYS 720, although none were reported for YYS 360 and YYS 540.

CONCLUSION

In this study, a notably low frequency of adverse reactions associated with the YYS series was observed.

Adipose tissue reconstruction facilitated with low immunogenicity decellularized adipose tissue scaffolds

There is currently an urgent need to develop engineered scaffolds to support new adipose tissue formation and facilitate long-term maintenance of function and defect repair to further generate prospective bioactive filler materials capable of fulfilling surgical needs. Herein, adipose regeneration methods were optimized and decellularized adipose tissue (DAT) scaffolds with good biocompatibility were fabricated. Adipose-like tissues were reconstructed using the DAT and 3T3-L1 preadipocytes, which have certain differentiation potential, and the regenerative effects of the engineered adipose tissuesin vitroandin vivowere explored. The method improved the efficiency of adipose removal from tissues, and significantly shortened the time for degreasing. Thus, the DAT not only provided a suitable space for cell growth but also promoted the proliferation, migration, and differentiation of preadipocytes within it. Following implantation of the constructed adipose tissuesin vivo, the DAT showed gradual degradation and integration with surrounding tissues, accompanied by the generation of new adipose tissue analogs. Overall, the combination of adipose-derived extracellular matrix and preadipocytes for adipose tissue reconstruction will be of benefit in the artificial construction of biomimetic implant structures for adipose tissue reconstruction, providing a practical guideline for the initial integration of adipose tissue engineering into clinical medicine.

The microalga Volvox carteri as a cell supportive building block for tissue engineering

Background

V. carteri f. nagariensis constitutes, in its most simplified form, a cellularized spheroid built around and stabilised by a form of primitive extracellular matrix (ECM).

Methods

We developed a modular approach to soft tissue engineering, by compact stacking V. carteri-based building blocks. This approach is made possible by the structure and cell adhesive properties of these building blocks, which results from the composition of their algal ECM.

Results

A primary biocompatibility assessment demonstrated the cytocompatibility of the algal suspension, its histogenesis-promoting properties, and that it did not induce an inflammatory response in vitro. These results allowed us to consider the use of this algal suspension for soft tissue augmentation, and to initiate an in vivo biocompatibility study. V. carteri exhibited cellular fate-directing properties, causing (i) fibroblasts to take on an alkaline phosphatase+ stem-cell-like phenotype and (ii) both human adipose-derived stem cells and mouse embryonic stem cells to differentiate into preadipocytes to adipocytes. The ability of V. carteri to support histogenesis and adipogenesis was also observed in vivo by subcutaneous tissue augmentation of athymic mice, highlighting the potential of V. carteri to support or influence tissue regeneration.

Conclusions

We present for the first time V. carteri as an innovative and inspiring biomaterial for tissue engineering and soft tissue regeneration. Its strategies in terms of shape, structure and composition can be central in the design of a new generation of bio-inspired heterogeneous biomaterials recapitulating more appropriately the complexity of body tissues when guiding their regeneration.

Implications for cumulative and prolonged clinical improvement induced by cross-linked hyaluronic acid: An in vivo biochemical/microscopic study in humans

In photoaged human skin, type I collagen fragmentation impairs dermal extracellular matrix (ECM) integrity, resulting in collapsed/contracted fibroblasts with reduced type I procollagen synthesis. Injections of cross-linked hyaluronic acid (CL-HA) reverse these deleterious changes. To investigate the time course and effects of biochemical changes induced by injected CL-HA, particularly whether fibroblast activation leads to accumulation/deposition of dermal collagen, we injected CL-HA into photoaged skin of human participants over 60 years-old and performed biochemical/microscopic analyses of skin samples. Beginning 1 week post-injection and lasting 6-9 months, fibroblasts exhibited activation, including increased immunostaining and gene expression of markers of type I collagen synthesis, such as heat shock protein 47 and components of the transforming growth factor-β pathway. At 1 week post-injection, multiphoton microscopy revealed elongation/stretching of fibroblasts, indicating enhanced dermal mechanical support. At 4 weeks, second-harmonic generation microscopy revealed thick collagen bundles densely packed around pools of injected CL-HA. At 12 months, accumulation of thick collagen bundles was observed and injected CL-HA remained present in substantial amounts. Thus, by occupying space in the dermal ECM, injected CL-HA rapidly and durably enhances mechanical support, stimulating fibroblast elongation and activation, which results in thick, densely packed type I collagen bundles accumulating as early as 4 weeks post-injection and continuing for at least a year. These observations indicate that early and prolonged clinical improvement following CL-HA injection results from space-filling and collagen deposition. As type I collagen has an estimated half-life of 15 years, our data provide the foundations for optimizing the timing/frequency of repeat CL-HA injections.

Ten-Year Follow-Up of Orbital Volume Augmentation With Calcium Hydroxyapatite Filler in Postenucleation Socket Syndrome

PURPOSE

To describe the efficacy and persistence of injectable calcium hydroxyapatite (CAHY) to correct orbital volume deficit in postenucleation socket syndrome.

METHODS

An observational study was conducted as a clinical review of all patients in the authors' practice who received injectable CAHY placed in the extraconal and intraconal space to increase orbital volume with a 10-year follow up. The amount of CAHY to be injected was defined according to the degree of orbital volume deficit. Patients previously treated with radiotherapy or with a conjunctival fornix insufficient to accommodate the external prosthesis were excluded. All the patients with at least 10 years of follow up were included in the study.

RESULTS

Thirty-one postenucleation socket syndrome patients received injectable CAHY for orbital volume augmentation, with a 10-year follow up. The mean amount of preoperative relative enophthalmos measured by Hertel's exophthalmometry was 14.16 ± 2.15. An increase in the mean orbital volume of 3.35 ± 0.91 at 6 months and 2.97 ± 1.35 at 10 years was obtained. The mean follow-up was 219 ± 18 months (range, 184-240). Patients demonstrated clinical and cosmetic improvement that was observed to continue for 10 years. The complications were peribulbar ecchymosis, 2 extrusions of the internal prosthesis, and 2 ptosis.

CONCLUSIONS

Injectable CAHY provides safe, simple, repeatable, and cost-effective technique to treat volume deficiency in the enophthalmic orbit in the long term. The volume augmentation obtained with this semipermanent filler demonstrated a lasting effect in the orbit with negligible loss of volume at 10 years.

Dermal Fillers in the Treatment of Acne Scars: A Review

Acne vulgaris (AV) is the eighth most common disease in the world. This condition can impair the affected patients' social and psychological functioning and lower their quality of life. In general, scar reduction, rather than complete scar removal, is the aim of AV treatment. Dermal abrasion, chemical peeling, laser resurfacing, subcision, punch methods, tissue-improving substances, and dermal fillers are the currently available therapeutic options. In this study, we focused on the rapidly developing field of dermal fillers used alone or in combination with other therapies to reconstruct skin affected by acne scars and to evaluate the improvement of facial appearance after using different types of dermal fillers.

Enhanced skin neocollagenesis through the transdermal delivery of poly-L-lactic acid microparticles by using a needle-free supersonic atomizer

In this study, a spindle-type nozzle was designed to accelerate poly-L-lactic acid (PLLA) microparticles to supersonic velocities for the transdermal delivery of these microparticles to rats. This approach is needle- and pain-free and enhances skin collagen regeneration. The addition of PLLA microparticles at a concentration of 2 mg/mL did not hinder the growth of 3 T3 fibroblasts and Raw264.7 macrophages. The TNF-α assay revealed no obvious inflammation effect of PLLA microparticles at a concentration of 1 mg/mL. A time-lapse recording revealed that after being cocultured with PLLA microparticles for 24 h, Raw264.7 macrophages gradually approached and surrounded the PLLA microparticles. When 3 T3 fibroblasts were cocultured with Raw264.7 macrophages, which were stimulated using PLLA microparticles, collagen synthesis was increased by approximately 60 % compared with that in samples without PLLA microparticles. In vivo animal experiments indicated that after the transdermal delivery of 10 shots of PLLA microparticles through the supersonic atomizer, no obvious changes or damage to the back skin of Sprague-Dawley rats was observed. More importantly, numerous PLLA microparticles penetrated the rat epidermis into the dermal layer. We found macrophages and fibroblasts present close to the PLLA microparticles. Moreover, only mild or no inflammation reaction was observed. Masson staining revealed that after 6-week implantation, 6 % and 12 % of PLLA microparticles significantly stimulated collagen regeneration in 6-week-old and 32-week-old rats. In addition, picrosirius red staining revealed a significant increase in collagen regeneration, especially for type III collagen, following the 6-week implantation of PLLA microparticles. In summary, this study demonstrated an easy, pain-free, nondestructive approach for introducing PLLA microparticles into the dermal layer by using a supersonic atomizer to stimulate collagen regeneration in vivo.

Adverse Reactions Associated with Dermal Fillers in the Oral and Maxillofacial Region: A Venezuelan Experience

BACKGROUND

Dermal facial fillers are increasingly popular. Published reports on the clinical and histopathologic characteristics related to adverse reactions to dermal fillers in the facial region have been relatively well documented. This study adds to the literature on adverse reactions to injected filler in the oral and maxillofacial region in a South American population.

METHODS

A retrospective, descriptive cross-sectional study (2019-2020) was performed. The study population was a dermatology service in Venezuela. Clinical and histopathologic features of patients with adverse effects were documented.

RESULTS

A total of 35 cases of adverse reactions associated with cosmetic filler procedures were diagnosed during the analyzed period; of these, six cases (17.1%) involved the oral and maxillofacial region. All cases occurred in women. The mean age at diagnosis was 59.3 years (58-73). In three cases, dermal fillers were used in different locations on the face, while three involved the lips. Five patients exhibited adverse reactions to lip filler. All six cases were histopathologically diagnosed as foreign body reactions to injected material. Four and two cases revealed microscopic features compatible with hyaluronic acid and polymethylmethacrylate, respectively.

CONCLUSION

Reflecting the dramatic increase in cosmetic procedures with soft tissue fillers, this study contributed by reporting six cases of foreign body reaction involving the oral and maxillofacial region, confirmed with biopsy and histopathology.

Poly-D,L-Lactic Acid Stimulates Angiogenesis and Collagen Synthesis in Aged Animal Skin

Angiogenesis promotes rejuvenation in multiple organs, including the skin. Heat shock protein 90 (HSP90), hypoxia-inducible factor-1 alpha (HIF-1α), and vascular endothelial growth factor (VEGF) are proangiogenic factors that stimulate the activities of phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and extracellular signal-regulated kinase 1/2 (ERK1/2). Poly-D,L-lactic acid (PDLLA), polynucleotide (PN), and calcium hydroxyapatite (CaHA) are dermal fillers that stimulate the synthesis of dermal collagen. However, it is not yet known whether these compounds promote angiogenesis, which leads to skin rejuvenation. Here, we evaluated whether PDLLA, PN, and CaHA stimulate angiogenesis and skin rejuvenation using H₂O₂-treated senescent macrophages and endothelial cells as an in vitro model for skin aging, and we used young and aged C57BL/6 mice as an in vivo model. Angiogenesis was evaluated via endothelial cell migration length, proliferation, and tube formation after conditioned media (CM) from senescent macrophages was treated with PDLLA, PN, or CaHA. Western blot showed decreased expression levels of HSP90, HIF-1α, and VEGF in senescent macrophages, but higher expression levels of these factors were found after treatment with PDLLA, PN, or CaHA. In addition, after exposure to CM from senescent macrophages treated with PDLLA, PN, or CaHA, senescent endothelial cells expressed higher levels of VEGF receptor 2 (VEGFR2), PI3K, phosphorylated AKT (pAKT), and phosphorylated ERK1/2 (pERK1/2) and demonstrated greater capacities for cell migration, cell proliferation, and tube formation. Based on the levels of 4-hydroxy-2-nonenal, the oxidative stress level was lower in the skin of aged mice injected with PDLLA, PN, or CaHA, while the tumor growth factor (TGF)-β1, TGF-β2, and TGF-β3 expression levels; the density of collagen fibers; and the skin elasticity were higher in the skin of aged mice injected with PDLLA, PN, or CaHA. These effects were greater in PDLLA than in PN or CaHA. In conclusion, our results are consistent with the hypothesis that PDLLA stimulates angiogenesis, leading to the rejuvenation of aged skin. Our study is the first to show that PDLLA, PN, or CaHA can result in angiogenesis in the aged skin, possibly by increasing the levels of HSP90, HIF-1α, and VEGF and increasing collagen synthesis.

An Update on the Clinical Efficacy and Safety of Collagen Injectables for Aesthetic and Regenerative Medicine Applications

Soft tissues diseases significantly affect patients quality of life and usually require targeted, costly and sometimes constant interventions. With the average lifetime increase, a proportional increase of age-related soft tissues diseases has been witnessed. Due to this, the last two decades have seen a tremendous demand for minimally invasive one-step resolutive procedures. Intensive scientific and industrial research has led to the recognition of injectable formulations as a new advantageous approach in the management of complex diseases that are challenging to treat with conventional strategies. Among them, collagen-based products are revealed to be one of the most promising among bioactive biomaterials-based formulations. Collagen is the most abundant structural protein of vertebrate connective tissues and, because of its structural and non-structural role, is one of the most widely used multifunctional biomaterials in the health-related sectors, including medical care and cosmetics. Indeed, collagen-based formulations are historically considered as the "gold standard" and from 1981 have been paving the way for the development of a new generation of fillers. A huge number of collagen-based injectable products have been approved worldwide for clinical use and have routinely been introduced in many clinical settings for both aesthetic and regenerative surgery. In this context, this review article aims to be an update on the clinical outcomes of approved collagen-based injectables for both aesthetic and regenerative medicine of the last 20 years with an in-depth focus on their safety and effectiveness for the treatment of diseases of the integumental, gastrointestinal, musculoskeletal, and urogenital apparatus.

Clinical and histological comparative outcomes after injections of poly-L-lactic acid and calcium hydroxyapatite in arms: A split side study

BACKGROUND

Although much has been published on the use of poly-L-lactic acid (PLLA) and calcium hydroxyapatite (CaHA) for off-face indications, questions remain regarding their exact mechanisms of action in subcutaneous tissue and their comparative efficacy.

OBJECTIVE

To present the clinical and histological results of the PLLA and CaHA injections into the opposing arms of the same patients.

METHODS

Five women received superficial subcutaneous injections of PLLA into the left arm and CaHA into the right arm. After three sessions, the clinical and histological outcomes were analyzed.

RESULTS

After the first session, three patients showed improvement in the right arm (CaHA), but at the end of study, two patients showed better results in the left arm (PLLA). Histologically, moderate to intense lymphocytic and giant cell infiltrate, as well as collagen and elastic fiber neoformation, were observed equally near the particles of both products. Dermis had no inflammatory or fiber alterations.

CONCLUSION

In this study, there were no clinical differences between these two fillers. Despite current thinking and previous histological studies, we found both products produced moderate to intense inflammatory reaction, as well as collagenic/elastogenic fiber neoformation, only in the subcutaneous tissue of the immediate vicinity and surrounding the individual filler particles.

Management of a Large Quantity of Permanent Gluteal Copolyamide Fillers (Aqualift/Activegel): Literature Review and Algorithm

Buttock augmentation is a commonly performed aesthetic surgery. Several methods have been described, but only the use of implants or autologous fat is consensually deemed safe and effective. Synthetic fillers in gluteal augmentation have been described despite potential severe long-term complications, both medical and aesthetic. The aim of this study is to report a series of 2 consecutive cases who underwent buttock and hip augmentation with large volumes of permanent copolyamide filler requiring surgical removal due to significant complications. Based on these cases and a review of recent literature, a management algorithm is proposed. The authors conducted a retrospective chart review of 2 consecutive cases of failed copolyamide filler augmentations in the gluteal and inguinal regions. The authors conducted a literature overview using PubMed (National Institutes of Health, Bethesda, MD) and Google Scholar (Google, Mountain View, CA) to include all articles concerning the removal of large quantities of permanent copolyamide fillers. Based on the physical properties of copolyamide, resection of the filler was performed by percutaneous aspiration with liposuction cannulas, with varying infiltration protocols. Both cases showed successful removal of major parts of the filler; however, residual material tended toward migration, requiring a secondary intervention. Hydrated low-pressure aspiration can manage nonintegrated gluteal copolyamide filler but will achieve only partial resection. Literature shows that radical excision is possible, however, with major drawbacks in function and aesthetics. Moreover, in acute inflammation and infection, an open approach should be preferred.

Level of Evidence 5

Duration of Effect and Associated Factors of Injection Laryngoplasty

OBJECTIVE

Injection laryngoplasty (IL) has become a mainstay in the treatment of unilateral vocal fold paralysis due to technical ease and avoidance of open surgery. The duration of IL effect depends on the injected material and has not been defined clearly. We aimed to define the effective duration of IL and to investigate the associated factors.

METHODS

Fifty-nine patients who underwent IL for unilateral vocal fold paralysis were included. IL was performed using a cricothyroid membrane approach under local anesthesia. During follow-up, in cases that developed subjective hoarseness with objective glottic insufficiency, a second IL was performed, and loss of IL effect was recorded. The duration of IL was analyzed using Kaplan-Meier estimates, and the associations between duration of effect and various factors such as postinjection voice therapy, injected material, and cause of paralysis were investigated using log-rank test.

RESULTS

Of 59 patients, 20 (33.9 %) received a second IL. The median time interval between the first and second IL was 3.3 months (95% CI, 0.4∼27.8 months). The mean duration of effect after IL was 42.5 months (95% CI, 32.1∼52.9 months), and the rate of persisting effect was 63.4% at 1-year after IL (1-year effect rate) and 59.4% at 2 years after IL. The 1-year effect rate was 80.8% in cases with postinjection voice therapy and 57.8% in those without postinjection voice therapy (P = 0.084). Injected material, DM, HTN, patient age and sex, and cause of paralysis had no effect on the 1-year effect rate.

CONCLUSIONS

The mean duration of IL effect was 42.5 months, and the rate of persisting effect was 63.4% at 1-year after IL. There were no significant factors affecting the duration of effect, although the duration tended to be slightly longer in cases with postinjection voice therapy. Further study with a prospective, randomized design is needed.

Hyaluronic Acid Filler Incidentally Found During Mohs Micrographic Surgery: Observations in 36 Patients Regarding Skin Depth, Degradation Size, and Estimated Persistence Time

BACKGROUND

Although its clinical effect is reported to last up to 2 years, how long hyaluronic acid filler (HAF) histologically persists in the skin is unknown.

OBJECTIVE

To determine the approximate persistence time of HAF in the skin and to correlate persistence time with HAF histological appearance, size, depth, and location.

METHODS

Retrospective review of patient data and available frozen sections from 2003 to 2021 in which HAF was identified in 36 Mohs micrographic surgery patients.

RESULTS

Incidental HAF histologically persisted in the skin for as long as 10.75 years in 1 patient and 3 years or more in 36.8% (7/19) of the patients who remembered the time of implantation. HAF is more apparent in frozen sections stained with toluidine blue than those stained with hematoxylin and eosin. Although HAF volume tended to be less with time, fragmentation was present both early at 3 months and at 3 years or more. There was no correlation of persistence time with anatomic location or depth. In 90.3% of the cases (28/31), HAF was located in the subcutaneous fat. There was no granulomatous or giant cell response at any time period.

CONCLUSION

Hyaluronic acid filler may be seen histopathologically in the skin, usually in the subcutaneous fat, up to 10.75 years after implantation.

An Injectable Meta-Biomaterial: From Design and Simulation to In Vivo Shaping and Tissue Induction

A novel type of injectable biomaterial with an elastic softening transition is described. The material enables in vivo shaping, followed by induction of 3D stable vascularized tissue. The synthesis of the injectable meta-biomaterial is instructed by extensive numerical simulation as a suspension of irregularly fragmented, highly porous sponge-like microgels. The irregular particle shape dramatically enhances yield strain for in vivo stability against deformation. Porosity of the particles, along with friction between internal surfaces, provides the elastic softening transition. This emergent metamaterial property enables the material to reversibly change stiffness during deformation, allowing native tissue properties to be matched over a wide range of deformation amplitudes. After subcutaneous injection in mice, predetermined shapes can be sculpted manually. The 3D shape is maintained during excellent host tissue integration, with induction of vascular connective tissue that persists to the end of one-year follow-up. The geometrical design is compatible with many hydrogel materials, including cell-adhesion motives for cell transplantation. The injectable meta-biomaterial therefore provides new perspectives in soft tissue engineering and regenerative medicine.

In vivo inducing collagen regeneration of biodegradable polymer microspheres

Biodegradable polymer particles have been used as dermal fillers for pre-clinical and clinical trials. The impact of material properties of polymers is very important to develop products for aesthetic medicine such as dermal fillers. Herein, eight biodegradable polymers with different molecular weights, chemical compositions or hydrophilic-hydrophobic properties were prepared and characterized for systematical study for aesthetic medicine applications. Polymer microspheres with 20-100 μm were prepared. The in vitro degradation study showed that poly (L-lactic-co-glycolic acid) 75/25 microspheres degraded the fastest, whereas poly (L-lactic acid) (PLLA) microspheres with intrinsic viscosity of 6.89 ([η] = 6.89) with the highest molecular weight showed the slowest degradation rate. After these microspheres were fabricated dermal fillers according to the formula of Sculptra®, they were injected subcutaneously into the back skin of rabbits. In vivo results demonstrated that the degradation rate of microspheres strongly correlated with the foreign body reaction and collagen regeneration was induced by microspheres. The microspheres with faster degradation rate induced inflammatory response and the collagen regeneration maintained in shorter time. PLLA ([η] = 3.80) microsphere with a moderate molecular weight and degradation rate could strongly regenerate Type I and III collagen to maintain a long-term aesthetic medicine effect. These properties of size, morphology and degradation behavior would influence the foreign body reaction and collagen regeneration.

Collagen and the effect of poly-l-lactic acid based materials on its synthesis

Collagen is an important protein in various biological functions such as providing elasticity and waterproofing to the skin, structural stability to the cells in connective tissues (e.g. tendons, and bone) and stabilisation of atherosclerotic plaques. Collagen as a peptide with a peculiar triple helical structure is majorly composed of glycine and proline amino acids and is synthesised by fibroblasts via intracellular and extracellular mechanisms. Collagen plays an important role in wound healing, bone repair and plaque build-up during atherosclerosis. Various factors such as interleukins, insulin-like growth factor-I, nicotine, and glucose have been shown to influence collagen synthesis. This paper provides an overview of collagen structure, synthesis mechanisms, and the parameters that stimulate those mechanisms. Poly-l-lactic acid as a well-known biocompatible and biodegradable polymer has proved to stimulate collagen synthesis in various physical forms. As such, in this review special emphasis is laid on the effects of poly-l-lactic acid as well as its mechanism of action on collagen synthesis.

Comparative Analyses of Inflammatory Response and Tissue Integration of 14 Hyaluronic Acid-Based Fillers in Mini Pigs

Purpose

Hyaluronic acid (HA)-based dermal fillers have been approved for various clinical indications, both cosmetic and medical. Previous studies that have assessed the performance of HA dermal fillers have primarily focused on evaluating filler durability, and only a few have studied their distribution within the tissues. The present study aimed to compare tissue integration of various types of HA dermal fillers having different clinical indications and varying injection depths.

Methods

To examine the local inflammatory response and distribution pattern of 14 HA dermal fillers (six Neuramis [NEU], one Belotero [BEL], three Juvéderm [JUV], and four Restylane [RES]), each product was injected intradermally and subcutaneously at the backs of two male miniature pigs. Histopathological evaluation and visual examination of the tissue sections were conducted 1 and 4 weeks after injection.

Results

Mean inflammatory cell infiltration scores tended to be lower in response to fillers from the NEU and BEL series than to those from the JUV and RES series after intradermal and subcutaneous injection. Furthermore, the inflammatory response to fillers with higher physicochemical properties specifically designed for injection into deeper layers of the skin tended to be slightly higher than those designated for injection into more superficial layers. There was no significant difference in tissue integration according to clinical indication and injection depth, although fillers from the NEU and BEL series exhibited better tissue integration than those from the JUV and RES series.

Conclusion

Our findings not only suggest that the local inflammatory response and tissue integration differ across HA dermal filler products, but also that these parameters could vary according to the recommended clinical indication and injection depth of the products.

Evaluation of Cannula Safety in Injection of Poly-L-Lactic Acid

Background and Objective

Poly-L-lactic acid (PLLA) has been used in various medical applications for decades, including aesthetic ones. The use of a cannula technique in injecting PLLA has been proposed in order to lower the incidence rate of adverse events (AEs) following treatment. Such AEs include nodule formation, which may occur less frequently by fanning the product with a cannula, thus creating a more uniform product placement compared to that resulting from the use of a needle. Currently, however, there is a lack of comparative research regarding the safety of cannulas versus needles for PLLA injections, as the selection of either remains highly subjective. Therefore, the objective of our study was to investigate the safety of cannula use in the administration of PLLA, in order to report safety outcomes.

Materials and Methods

A single-center, retrospective chart review was conducted to examine the data of patients who had previously undergone treatment with PLLA in the form of Sculptra^® Aesthetic™ in the face and/or neck regions. Twenty-seven subject charts met eligibility. Descriptive data regarding treatment and follow-up visits were collected and analyzed.

Results

A total of seven AEs resulted from eighty-two treatment sessions (8.54%), with 6/27 patients having experienced at least one AE (22.22%). Mild bruising was the most commonly reported AE (57.14%). The majority of the AEs were mild and transient in nature, with one moderate AE being a nodule that was possibly related to a concomitant treatment. All AEs were resolved with follow-up care.

Conclusion

Mild AEs such as bruising, swelling and pain should be expected following the use of a cannula for PLLA injections. However, the incidence rates of AEs following treatment can remain low if proper product preparation and treatment techniques are utilized.

In situ Adipogenesis in Biomaterials Without Cell Seeds: Current Status and Perspectives

For cosmetic and reconstructive purposes in the setting of small-volume adipose tissue damage due to aging, traumatic defects, oncological resections, and degenerative diseases, the current strategies for soft tissue replacement involve autologous fat grafts and tissue fillers with synthetic, bioactive, or tissue-engineered materials. However, they all have drawbacks such as volume shrinkage and foreign-body responses. Aiming to regenerate bioactive vascularized adipose tissue on biomaterial scaffolds, adipose tissue engineering (ATE) has emerged as a suitable substitute for soft tissue repair. The essential components of ATE include scaffolds as support, cells as raw materials for fat formation, and a tolerant local environment to allow regeneration to occur. The commonly loaded seeding cells are adipose-derived stem cells (ASCs), which are expected to induce stable and predictable adipose tissue formation. However, defects in stem cell enrichment, such as donor-site sacrifice, limit their wide application. As a promising alternative approach, cell-free bioactive scaffolds recruit endogenous cells for adipogenesis. In biomaterials without cell seeds, the key to sufficient adipogenesis relies on the recruitment of endogenous host cells and continuous induction of cell homing to scaffolds. Regeneration, rather than repair, is the fundamental dominance of an optimal mature product. To induce in situ adipogenesis, many researchers have focused on the mechanical and biochemical properties of scaffolds. In addition, efforts to regulate an angiogenic and adipogenic microenvironment in cell-free settings involve integrating growth factors or extracellular matrix (ECM) proteins onto bioactive scaffolds. Despite the theoretical feasibility and encouraging results in animal models, few of the reported cell-free biomaterials have been tested in humans, and failures of decellularized adipose tissues in adipogenesis have also been reported. In these cases, the most likely reason was the lack of supporting vasculature. This review summarizes the current status of biomaterials without cell seeds. Related mechanisms and influencing factors of in situ adipogenesis in cell-free biomaterials, dilemma in the development of biomaterials, and future perspectives are also addressed.

Clinical Experience with Treatment of Aquafilling Filler-Associated Complications: A Retrospective Study of 146 Cases

BACKGROUND

Aquafilling filler is used for breast and buttock augmentation, which are the most commonly performed cosmetic surgery procedures. However, complications after using Aquafilling filler for breast augmentation have been reported, and there are concerns regarding its use in large areas, such as the buttocks. We provide our experience with complications after breast augmentation and buttock augmentation using Aquafilling filler.

METHODS

This observational cohort study analyzed the data of 399 patients treated for filler-related complications at our institutes from September 2015 to November 2019. Of these patients, 146 underwent surgery to remove Aquafilling filler from the breast or buttock.

RESULTS

The mean time between Aquafilling filler use and complication onset was 38.5 ± 10.2 months. The average amount of filler material removed from one side of the breast or buttock was 285.5 ± 95.8 mL (range 150-750 mL). The most common complications were induration and masses (83.6%), followed by pain (52.1%), firmness (24.7%), asymmetry (10.3%), migration (8.2%), mastitis (6.8%), dimpling (6.2%), fever (3.4%), and sepsis (n = 1). After treatment, there was no recurrence of infection, and the patient satisfaction level based on the visual analogue scale was 8.0 ± 0.9.

CONCLUSIONS

Although Aquafilling filler is easily injectable and has long-term clinical effects, complications can occur. Furthermore, there are concerns regarding its toxicity and influence on the surrounding tissues. Hence, further research studies on Aquafilling filler and evidence regarding its long-term safety are needed.

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 .

Complications after cosmetic periocular filler: prevention and management

Soft tissue fillers are a mainstay in contemporary, minimally invasive facial rejuvenation procedures owing to timely results and minimal recovery period. Although associated with a low complication rate, soft tissue fillers are not without risk. Complications range from mild superficial skin irregularities to granuloma formation to vascular occlusion leading to skin necrosis or even blindness. Fillers vary in composition, elasticity, hydrophilicity and duration of effect that is tailored to specific cosmetic indications. Selecting the right product for the desired effect can cut down on unwanted outcomes. Severe adverse events can be avoided with safe injection technique, early recognition of symptoms and a thorough knowledge of the local anatomy. This review outlines several complications all providers should recognize and discusses strategies for their prevention and management.

Isolation, characterisation and phagocytic function of human macrophages from human peripheral blood

Macrophages are among the most important cells of the immune system. Among other functions, they take part in almost all defense actions against foreign bodies and bacteria, being particularly important in infections, wound healing, and foreign body reactions. Considering their importance for the health of the human body, as well as their important role in several diseases, the in vitro studies based on these cells, are a crucial research field. Taking all mentioned into account, this study describes a simple isolation method of human macrophages (MFUM-HMP-001 and MFUM-HMP-002 cell lines) from peripheral blood. For this purpose, the morphology, the viability, and the phagocytotic activity of the isolated cells were tested. The Immunostaining of MFUM-HMP-001 and MFUM-HMP-002 cells confirmed the macrophage cell markers CD68, CD80, and CD163/M130. The phagocytotic activity was marked in both MFUM-HMP-001 and MFUM-HMP-002 cells, as was the phagocytosis of the pHrodo green Escherichia coli bioparticles conjugates, which was enhanced with the addition of lipopolysaccharide. The cells were stable and exhibited good growth. According to our results, both cell lines are useful for the development of novel macrophage cell-based in vitro models.

Facial Soft Tissue Augmentation With Bellafill: A Review of 4 Years of Clinical Experience in 212 Patients

Introduction

Bellafill (Suneva Medical Inc) is a semipermanent injectable soft tissue filler composed of smooth and uniform polymethylmetacrylate (PMMA) microspheres suspended in a bovine collagen gel. It is a third generation PMMA filler, with more uniform shapes and sizes of the PMMA microspheres, which has been purported to decrease the incidence of granuloma formation.

Methods

We performed a retrospective review of our clinical experience from 2014 to 2017 with Bellafill as a soft tissue injectable filler in the following clinical scenarios: deep nasolabial folds, depressed facial acne scars, malar volume loss, temporal wasting, tear trough deformity, chin augmentation, angle of jaw augmentation, and lip augmentation. The primary outcome is the rate of adverse events, and the secondary outcome is subjective patient satisfaction.

Results

From 2014 to 2017, 842 syringes of Bellafill were administered to 212 patients, for a total of 417 procedures. Of the 417 procedures, 96 (23.0%) were for acne scars, 82 (19.7%) malar volume restorations, 65 (15.6%) nasolabial fold augmentations, 45 (10.8%) chin augmentations, 42 (10.1%) tear trough volume restorations, 28 (6.7%) temple volume restorations, 25 (6.0%) rhinoplasty touch-ups for small areas of nasal depression, 22 (5.3%) lip augmentations, and 12 (2.9%) jaw angle augmentations were performed. A range of 1 to 12 syringes were injected into each patient, over 1 to 3 sessions; 6 cases of adverse events occurred (1.4%). There were 4 cases of solitary nodules in the injection site, 1 case of lower eyelid oedema which persisted for 3 months and 1 case of lower lip oedema which resolved within hours. Patient satisfaction rates ranged from 83.3% for angle of jaw augmentation to 99.0% for improvement of acne scars.

Conclusion

Bellafill is a safe and effective option for a semipermanent soft tissue filler, with high patient satisfaction and a good safety profile.

Human Adipose Tissue Derivatives as a Potent Native Biomaterial for Tissue Regenerative Therapies

BACKGROUND

Human adipose tissue is a great source of translatable biomaterials owing to its ease of availability and simple processing. Reusing discardable adipose tissue for tissue regeneration helps in mimicking the exact native microenvironment of tissue. Over the past 10 years, extraction, processing, tuning and fabrication of adipose tissue have grabbed the attention owing to their native therapeutic and regenerative potential. The present work gives the overview of next generation biomaterials derived from human adipose tissue and their development with clinical relevance.

METHODS

Around 300 articles have been reviewed to widen the knowledge on the isolation, characterization techniques and medical applications of human adipose tissue and its derivatives from bench to bedside. The prospective applications of adipose tissue derivatives like autologous fat graft, stromal vascular fraction, stem cells, preadipocyte, adipokines and extracellular matrix, their behavioural mechanism, rational property of providing native bioenvironment, circumventing their translational abilities, recent advances in featuring them clinically have been reviewed extensively to reveal the dormant side of human adipose tissue.

RESULTS

Basic understanding about the molecular and structural aspect of human adipose tissue is necessary to employ it constructively. This review has nailed the productive usage of human adipose tissue, in a stepwise manner from exploring the methods of extracting derivatives, concerns during processing and its formulations to turning them into functional biomaterials. Their performance as functional biomaterials for skin regeneration, wound healing, soft tissue defects, stem cell and other regenerative therapies under in vitro and in vivo conditions emphasizes the translational efficiency of adipose tissue derivatives.

CONCLUSION

In the recent years, research interest has inclination towards constructive tissue engineering and regenerative therapies. Unravelling the maximum utilization of human adipose tissue derivatives paves a way for improving existing tissue regeneration and cellular based therapies and other biomedical applications.

Comparisons between fresh and cryopreserved fat injections in facial lipofilling

Background

Autologous fat is considered an ideal filler material, and the use of cryopreserved fat grafts is promising in terms of flexibility and efficiency. Therefore, cryopreserved fat grafts have become more common in recent years; however, their complications require further consideration.

Methods

We evaluated 53 patients who underwent facial lipofilling at our institution to confirm the clinical usefulness and safety of cryopreserved fat. Fresh fat injections with or without cryopreserved fat were administered. At one or more sites, 22 patients had a single fresh fat injection, four patients had two or more fresh fat injections, 16 patients had one fresh fat injection followed by one cryopreserved fat injection, six patients had one fresh fat injection followed by two cryopreserved fat injections, and five patients had two fresh fat injections and one or more cryopreserved fat injections.

Results

In total, 281 sets of injection procedures were performed at various sites, of which 170 involved one fresh fat injection, 89 involved one fresh fat injection and one cryopreserved fat injection, and 11 involved one fresh fat injection and two cryopreserved fat injections. One patient experienced self-resolving inflammation as a complication after the second injection in the right cheek. No statistically significant differences were found between the fresh and cryopreserved fat injections.

Conclusion

We suggest that cryopreserved fat is a useful and safe resource for multiple fat injections, with advantages including aseptic fat handling and the delicacy of the technique.

An evaluation of the host response to an interspinous process device based on a series of spine explants: Device for Intervertebral Assisted Motion (DIAM®)

Background

The objective of this study was to evaluate the host response to an interspinous process device [Device for Intervertebral Assisted Motion (DIAM^®)] based on a series of nine spine explants with a mean post-operative explant time of 35 months.

Methods

Explanted periprosthetic tissues were processed for histology and stained with H&E, Wright-Giemsa stain, and Oil Red O. Brightfield and polarized light microscopy were used to evaluate the host response to the device and the resultant particulate debris. The host response was graded per ASTM F981-04. Quantitative histomorphometry was used to characterize particle size, shape, and area per ASTM F1877-05. The presence or absence of bone resorption was also evaluated when bony tissue samples were provided.

Results

Periprosthetic tissues demonstrated a non-specific foreign body response composed of macrophages and foreign body giant cells to the DIAM^® device in most of the accessions. The foreign body reaction was not the stated reason for explantation in any of the accessions. Per ASTM F981-04, a "very slight" to "mild" to "moderate" chronic inflammatory response was observed to the biomaterials and particulate, and this varied by tissue sample and accession. Particle sizes were consistent amongst the explant patients with mean particle size on the order of several microns. Osteolysis, signs of toxicity, necrosis, an immune response, and/or device related infection were not observed.

Conclusions

Cyclic loading of the spine can cause wear in dynamic stabilization systems such as DIAM^®. The fabric nature of the DIAM^® device's polyethylene terephthalate jacket coupled with the generation of polymeric particulate debris predisposes the device to a foreign body reaction consisting of macrophages and foreign body giant cells. Although not all patients are aware of symptoms associated with a foreign body reaction to a deeply implanted device, surgeons should be aware of the host response to this device.

PMMA Safety for Facial Filling: Review of Rates of Granuloma Occurrence and Treatment Methods

PMMA is composed of microspheres suspended in bovine collagen. Once injected in a dermal area, the carrier is absorbed, giving place to collagen that gives volume and maintains the spheres in the place. This process may give origin to exacerbate foreign body reaction and granuloma. The frequency of such complication is not clear. The primary objective was to review and compare the frequencies of granuloma between the published studies. The secondary aim was to compare the therapies and efficacies. The series of cases in which PMMA was used as facial filler were reviewed, and the rate of granulomas was compared; the case report studies describing those complications were also reviewed, and the therapies and outcomes were quantified. The data showed general frequency of PMMA-related complications of 4.9% and granulomas 1.9%; the incidence of granuloma was 1/2075 patients-year, and the time to development ranged from 6 to 180 months. The most used therapies were steroid, surgery or both, with satisfactory results. In conclusion, considering the actual risks and benefits of PMMA, we may affirm that it is a safe filler; doctors and patients must be conscious of potential risks when deciding for its use. 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.

Replacement of gluteal implants by polymethyl methacrylate filler: case report

Silicone prostheses are an alternative to shape the buttock but further studies are still needed to support the effectiveness of its use. A patient sought medical attention for being dissatisfied with the glutaeal silicone prostheses inserted using subcutaneous technique four years before. The treatment adopted was prosthesis removal surgery, and subsequent filling with PMMA.

Rehabilitation of the Dysmorphic Lower Eyelid From Hyaluronic Acid Filler: What to Do After a Good Periocular Treatment Goes Bad

BACKGROUND

Chronic, long-lasting edema accompanied by the Tyndall effect as a delayed reaction to hyaluronic acid (HA) filler injection seems to occur exclusively in the eyelids.

OBJECTIVES

The authors sought to present a treatment algorithm for management of patients with chronic lower eyelid edema as a delayed complication of HA filler injection.

METHODS

Retrospective study including 61 patients with delayed-onset chronic periocular edema following uneventful HA filler injection in the lower eyelids or cheeks. All patients underwent hyaluronidase enzyme dissolution followed by secondary treatment. Three retreatment options were presented: (1) observation, (2) secondary treatment with HA filler, and (3) lower eyelid blepharoplasty.

RESULTS

All patients underwent filler dissolution using hyaluronidase. The mean age was 48 years and 97% of the patients were female. Single treatment was effective in 92% of patients with 8% requiring another hyaluronidase injection to completely eradicate residual edema. Six patients (10%) were satisfied after hyaluronidase only and 6 patients (10%) underwent lower eyelid blepharoplasty. Secondary treatment with HA filler was performed in 48 patients (80%). All were satisfied with final results without further edema in the follow-up period.

CONCLUSIONS

Delayed-onset chronic lower eyelid edema is a frequent HA-related complication and cause of concern when considering periocular HA treatment. Previous treatment has been limited to either hyaluronidase only or blepharoplasty as a secondary solution after hyaluronidase, with only a minority of patients satisfied. Hyaluronidase, shortly followed by HA filler retreatment, is a safe and effective solution.

LEVEL OF EVIDENCE: 4

Vascular Compromise After Soft Tissue Facial Fillers: Case Report and Review of Current Treatment Protocols

The use of facial fillers for soft tissue augmentation is becoming a mainstream treatment modality for patients. Owing to the relative ease of administration, as well as the lucrative nature of such procedures, the number of providers offering facial fillers has been expanding. Although many adverse effects of facial fillers are minor and localized to the site of injection, 1 potential serious, albeit uncommon, adverse effect of facial filler treatment is avascular necrosis. In this article, we review soft tissue filler complications and describe the case of a 52-year-old female patient in whom vascular compromise developed after facial filler administration. In addition to reviewing complications and best practices for treatment management, we discuss anatomic considerations, present an overview of the most common filler materials, describe histologic changes with dermal fillers, and discuss litigation consequences with the use of these minimally invasive procedures. Although facial filler treatment is regarded as a minimally invasive and extremely safe procedure, it is not without complications. Avascular necrosis after soft tissue augmentation with facial fillers is exceedingly rare, with only a few cases reported in the literature, but practitioners who offer this procedure need to be well versed in treatment protocols.

Biochemical and biomechanical comparisions of decellularized scaffolds derived from porcine subcutaneous and visceral adipose tissue

Decellularized adipose tissue (DAT) is a promising biomaterial for adipose tissue engineering. However, there is a lack of research of DAT prepared from xenogeneic porcine adipose tissue. This study aimed to compare the adipogenic ability of DAT derived from porcine subcutaneous (SDAT) and visceral adipose tissue (VDAT). The retention of key collagen in decellularized matrix was analysed to study the biochemical properties of SDAT and VDAT. For the biomechanical study, both DAT materials were fabricated into three-dimensional (3D) porous scaffolds for rheology and compressive tests. Human adipose-derived stem cells (ADSCs) were cultured on both scaffolds to further investigate the effect of matrix stiffness on cellular morphology and on adipogenic differentiation. ADSCs cultured on soft VDAT exhibited significantly reduced cellular area and upregulated adipogenic markers compared to those cultured on SDAT. In vivo results revealed higher adipose regeneration in the VDAT compared to the SDAT. This study further demonstrated that the relative expression of collagen IV and laminin was significantly higher in VDAT than in SDAT, while the collagen I expression and matrix stiffness of SDAT was significantly higher in comparison to VDAT. This result suggested that porcine adipose tissue could serve as a promising candidate for preparing DAT.

Effect of bFGF and fibroblasts combined with hyaluronic acid-based hydrogels on soft tissue augmentation: an experimental study in rats

Background

Hyaluronic acid (HA) has been applied as a primary biomaterial for temporary soft tissue augmentation and as a carrier for cells and the delivery of growth factors to promote tissue regeneration. Although HA derivatives are the most versatile soft tissue fillers on the market, they are resorbed early, within 3 to 12 months. To overcome their short duration, they can be combined with cells or growth factors. The purpose of this study was to investigate the stimulating effects of human fibroblasts and basic fibroblast growth factors (bFGF) on collagen synthesis during soft tissue augmentation by HA hydrogels and to compare these with the effects of a commercial HA derivative (Restylane®).

Methods

The hydrogel group included four conditions. The first condition consisted of hydrogel (H) alone as a negative control, and the other three conditions were bFGF-containing hydrogel (HB), human fibroblast-containing hydrogel (HF), and human fibroblast/bFGF-containing hydrogel (HBF). In the Restylane® group (HGF), the hydrogel was replaced with Restylane® (R, RB, RF, RBF). The gels were implanted subdermally into the back of each nude mouse at four separate sites. Twelve nude mice were used for the hydrogel (n = 6) and Restylane® groups (n = 6). The specimens were harvested 8 weeks after implantation and assessed histomorphometrically, and collagen synthesis was evaluated by RT-PCR.

Results

The hydrogel group showed good biocompatibility with the surrounding tissues and stimulated the formation of a fibrous matrix. HBF and HF showed significantly higher soft tissue synthesis compared to H (p < 0.05), and human collagen type I was well expressed in HB, HF, and HBF; HBF showed the strongest expression. The Restylane® filler was surrounded by a fibrous capsule without any soft tissue infiltration from the neighboring tissue, and collagen synthesis within the Restylane® filler could not be observed, even though no inflammatory reactions were observed.

Conclusion

This study revealed that HA-based hydrogel alone or hydrogel combined with fibroblasts and/or bFGF can be effectively used for soft tissue augmentation.

Delayed sclerosing granulomatous reaction to dermal filler injection of poly-hydroxyethyl-methacrylate suspended in hyaluronic acid: Histochemical and confocal laser scanning microscopical analysis

Re-absorbable dermal fillers of poly-hydroxyethyl-methacrylate suspended in hyaluronic acid are considered overall safe and well tolerable because of biocompatibility; nevertheless, rarely, late, or early adverse reactions may occur.

Gluteal Augmentation with Polymethyl Methacrylate: A 10-year Cohort Study

Supplemental Digital Content is available in the text.

Background:

Many techniques for buttocks augmentation have been developed and published, for a more natural, satisfactory, and safe result for the patient. It has been a challenge to find a technique that presented not only volume gain but also gluteal remodeling.

Methods:

A total of 1,681 patients who underwent gluteal augmentation with Polymethyl methacrylate (PMMA) between 2009 and 2018 were selected for this retrospective cohort study. Data collected included demographics, procedures data, and postoperative outcomes. Side effects were calculated and compared using the Student’s t test.

Results:

A total of 1,681 patients (1,583 women and 98 men) who underwent 2,770 gluteal fillings had their cases retrospectively analyzed. They were injected with 540,751.00 mL of PMMA injected. The patients’ mean age was 39 years, and the mean volume injected in each section was 237 mL during the first procedure and 147 mL during the second procedure. The authors observed 52 cases presenting side effects, representing a rate of 1.88% of 2,770 procedures carried out. The statistically significant (P = 0.02) presence of side effects was detected in relation to the total filling volume.

Conclusions:

This study has demonstrated that gluteal augmentation with PMMA is one of the best options for this type of procedure. In addition, the findings suggest that the guidelines concerning gluteal augmentation must include PMMA filler as an option because PMMA proved to cause few side effects, as demonstrated by this patient cohort.

Efficacy and safety of newly developed cross-linked dextran gel injection for glans penis augmentation with a novel technique

There is no safe and effective standard method for glans penis augmentation. Furthermore, there has been scant research on glans penis augmentation due to a poor understanding of glans anatomy, technical difficulty, and a lack of suitable substances for augmentation. Cross-linked dextran gel is a newly developed filler for soft-tissue augmentation. We evaluated the efficacy and safety of using a novel technique to inject cross-linked dextran gel for glans penis augmentation during a 24-week follow-up study. This prospective, single-arm, multicenter study enrolled twenty healthy adult men who underwent glans penis augmentation between June and August 2013. Cross-linked dextran gel was injected into the glans penis using a simple and easy technique. The sizes of the glans penis and individual satisfaction were assessed. Any adverse event was also reported. A total of 18 individuals were analyzed; two of them were lost to follow-up. The mean procedure time and injected volume were about 30 min and 6.6 ± 0.9 ml, respectively. The mean surface areas of the glans at baseline and 24 weeks were 20.0 ± 3.5 cm² and 33.6 ± 5.4 cm², respectively, representing a mean increase of 68.7% ± 14.0% (P < 0.001). Sixteen individuals (88.9%) were satisfied with the outcomes, and none were dissatisfied. There were no serious adverse events during the study. Cross-linked dextran gel injection for glans penis augmentation was easy and showed a significant augmentative effect on the glans penis, good durability, and was well tolerated without serious adverse events. Therefore, cross-linked dextran gel injection may be an effective, new technique for glans penis augmentation.

Influence of the PLGA/gelatin ratio on the physical, chemical and biological properties of electrospun scaffolds for wound dressings

Chronic wounds are a global health problem, and their treatments are difficult and long lasting. The development of medical devices through tissue engineering has been conducted to heal this type of wound. In this study, it was demonstrated that the combination of natural and synthetic polymers, such as poly (D-L lactide-co-glycolide) (PLGA) and gelatin (Ge), were useful for constructing scaffolds for wound healing. The aim of this study was to evaluate the influence of different PLGA/gelatin ratios (9:1, 7:3 and 5:5 (v/v)) on the physical, chemical and biological properties of electrospun scaffolds for wound dressings. These PLGA/Ge scaffolds had randomly oriented fibers with smooth surfaces and exhibited distances between fibers of less than 10 μm. The 7:3 and 5:5 PLGA/Ge scaffolds showed higher swelling, hydrophilicity and degradation rates than pure PLGA and 9:1 (v/v) PLGA/Ge scaffolds. Young's moduli of the scaffolds were 72 ± 10, 48 ± 6, 58 ± 6 and 6 ± 1 MPa for the pure PLGA scaffold and the 9:1, 7:3 and 5:5 (v/v) PLGA/Ge scaffolds, respectively. Mesenchymal stem cells (MSCs) seeded on all the PLGA/Ge scaffolds were viable, and the cells were attached to the fibers at the different analyzed timepoints. The most significant proliferation rate was observed for cells on the 7:3 PLGA/Ge scaffolds. Biocompatibility analysis showed that all the scaffolds produced inflammation at the first week postimplantation; however, the 7:3 and 5:5 (v/v) PLGA/Ge scaffolds were degraded completely, and there was no inflammatory reaction observed at the fourth week after implantation. In contrast, the 9:1 PLGA/Ge scaffolds persisted in the tissue for more than four weeks; however, at the eighth week, no traces of the scaffolds were found. In conclusion, the scaffolds with the 7:3 PLGA/Ge ratio showed suitable physical, chemical and biological properties for applications in chronic wound treatments.

Hyaluronic Acid Gel Biodegradation After Intrapalpebral and Intraorbital Injection in Experimental Study

PURPOSE

Amid the increasing clinical application of hyaluronic acid (HA) fillers in the ocular adnexa is a paucity of histological data concerning the fate of the injected material. The current study documents the in vivo biodegradation of HA deposited in the eyelid and orbit.

METHODS

The study included 22 chinchilla rabbits. The right upper eyelid of 12 rabbits received a single 0.2 ml Restylane (Galderma, Uppsala, Sweden) subcutaneous injection. In 10 different rabbits, the right orbit was injected with 1.0 ml Restylane SubQ (Galderma, Uppsala, Sweden) in the extraconal space. The rabbits in the eyelid group were euthanized at 2 weeks, 1 month, 2, 4, 6, and 9 months, while the rabbits in the orbit group were euthanized at 1 month, 3, 6, 12, and 18 months. Histological analysis was performed on the harvested samples.

RESULTS

In the eyelid, the HA assumed a sponge-like structure that diminished gradually over time. At 9 months, the injected HA partially persisted, mainly in the peripheral areas of injection. A similar histologic pattern was observed in the injected orbits, with slow changes persisting at the eighteenth month. In both cohorts, clear signs of collagen deposition and pseudocapsule formation were observed around HA droplets, with no signs inflammation.

CONCLUSIONS

HA injected subcutaneously into the eyelid and orbit of rabbits undergoes slow and gradual biodegradation, with HA persisting to no less than 9 months in the eyelid and 18 months in orbit. Neocollagen synthesis and lack of hyaluronidase activity could explain the unexpectedly prolonged HA persistence.

The efficacy of powdered polydioxanone in terms of collagen production compared with poly-L-lactic acid in a murine model

BACKGROUND

There are many collagen-stimulating fillers, including calcium hydroxyapatite, polycaprolactone (PCL), and poly-L-lactic acid (PLLA), and other materials have been tested. Polydioxanone (PDO) has recently been used as absorbable thread-lifting material due to its collagen-forming effects. PDO in powdered form is expected to be a good material for collagen-producing fillers.

OBJECTIVES

To evaluate the collagen-producing effects of powdered PDO injection compared with PLLA injection in a murine model.

MATERIALS AND METHODS

Powdered PDO mixed with sodium carboxymethyl cellulose, PLLA, and phosphate-buffered saline was injected on dorsal skin of 8-week-old rat. Tissue samples were obtained 1, 2, and 12 weeks after the procedures for histopathologic review and for real-time PCR to quantify collagen and tissue growth factors.

RESULTS

Both PLLA and powdered PDO injections induced granulomatous reactions. Collagen type 1, collagen type 3, TGF-β1, TGF-β2, and TGF-β3 showed increases 2 weeks after injection but decreased 12 weeks after injection for both powdered PDO and PLLA.

CONCLUSION

Our results suggested that powdered PDO injection induces collagen formation more effectively than PLLA injection. Therefore, PDO can be a good option for forming collagen.

Autoimmune/inflammatory syndrome induced by adjuvants-ASIA-related to biomaterials: analysis of 45 cases and comprehensive review of the literature

Systemic autoimmune or granulomatous disorders related to biomaterials of human use have rarely been described. The aim of this study was to report cases of autoimmune/inflammatory syndrome induced by adjuvants (ASIA) related to biomaterial injections and prostheses, mainly silicone, hyaluronic acid, acrylamides and methacrylate compounds in a Spanish patient cohort. This study is a retrospective analysis of clinical, laboratory, histopathological and follow-up data of 45 cases of patients suffering from late-onset, non-infectious inflammatory/autoimmune disorders related to bioimplants. Late onset was defined as 3 months or more post injection. Data were obtained through a further non-systematic but comprehensive review of the literature. Forty-five cases of late-onset adverse reactions related to biomaterial injections or prostheses were reviewed. All cases had systemic complaints that could be categorised as ASIA. In all but four patients, inflammatory features at the implantation site preceded distant or systemic manifestations. Abnormal blood tests were common. Localised inflammatory nodules and panniculitis in 40/45 (88.88%) evolved into a variety of disorders, viz., primary biliary cirrhosis, Sjögren's syndrome, sarcoidosis, human adjuvant disease, vasculitis, inflammatory bowel syndrome and inflammatory polyradiculopathy. Five (11.11%) cases presented primarily with systemic autoimmune disorders. Biomaterials and prostheses can provoke late-onset systemic autoimmune disorders fulfilling ASIA criteria, or present primarily local/regional inflammatory reactions that may eventually evolve into systemic autoimmune and/or granulomatous disorders which fall under ASIA.

Granulomatous Inflammation of the Upper Eyelid After Autologous Fat Injection

A 45-year-old female came to the clinic complaining of periorbital swelling and ptosis on the left upper eyelid that had started 6 months previously. She had received an autologous fat injection in the forehead 6 months prior, and there was no other ophthalmologic history. There were no abnormal findings, including pupil, extraocular movement, or fundus examination. There was eyebrow elevation of the left upper eyelid, and the marginal reflex distance 1 was 1 mm on the left eye compared to 4 mm on the right eye. There were a 2-cm-sized round and firm mass on the left upper eyelid that was not accompanied by tenderness. Orbital computed tomography showed heterogeneous infiltration with an ill-defined margin. Excisional biopsy and levator advancement were performed on the left upper eyelid, and histological findings showed chronic granulomatous inflammation with foreign body reaction and fat necrosis.A complete history for patient presentation with autologous fat injection is important when a periorbital mass is encountered clinically because granulomatous inflammation of the eyelid may occur after autologous fat injection in the forehead and can be related to migration of the injected fat.