Injectable Skin Fillers

Injectable fillers: current status, physicochemical properties, function mechanism, and perspectives

With the increasing understanding of the aging process and growing desire for minimally invasive treatments, injectable fillers have great potential for correcting and rejuvenating facial wrinkles/folds and contouring the face. However, considering the increasing availability of multiple soft tissue fillers, it is important to understand their inherent biophysical features and specific mechanism. Thus, in this review, we aim to provide an update on the current injectable filler products and analyze and compare their critical physicochemical properties and function mechanisms for volume-filling. Additionally, future trends and development processes for injectable fillers are also proposed.

Long-Term Efficacy and Tolerability of a Medium G' HA Filler with Tri-Hyal Technology on the Rejuvenation of the Mobile Facial Zone

Purpose

Injectable hyaluronic acid-based fillers are commonly used for the correction of skin contour irregularities and to smooth skin depressions formed by volume loss during the aging process. These fillers are particularly efficient to restore perioral skin depressions/wrinkles or to correct topographical anomalies. The European directives require a continuous evaluation of the performance of these medical devices, particularly for CE marked products.

Methods

An 18-month prospective randomized single-blind study for the efficacy and safety of ART FILLER Universal (AFU) was performed on the lips, the nasolabial folds, and the marionettes lines. The evaluations were performed on 153 subjects enrolled in this study. The efficacy, the longevity, and the safety were evaluated for the injected areas via area specific clinical scoring after a single injection with the filler and with no re-touch.

Results

We showed here that filler injection induced potent improvements of volume restoration after a single injection on all the treated areas. These beneficial properties of the filler were significant 3 weeks after injection and during the whole study period. Moreover, injections of the filler were well tolerated by the subjects. The recorded adverse events are routinely seen with HA fillers for face volume corrections, and most of these local reactions resolved within 14 days.

Conclusion

AFU was well tolerated and showed a continuous efficacy for at least 18 months, in exploratory analyses.

Comparative clinical study for the efficacy and safety of two different hyaluronic acid-based fillers with Tri-Hyal versus Vycross technology: A long-term prospective randomized clinical trial

BACKGROUND

Hyaluronic acid-based fillers have an immediate volumizing effect for the treatment of dermal contour deformities and to smooth dermal depressions formed by the loss of volume. A previous study on 2016-2018 has shown the efficacy and safety of the HA-based filler ART FILLER® Volume on the midface only, but not in a comparative manner.

METHODS

In this context, an 18 months prospective randomized single-blind study of the non-inferiority of ART FILLER® Volume versus the reference product Juvéderm Voluma® was performed on the midface, temple, and jawline, and non-comparative study on the chin. The efficacy and the longevity were evaluated for the selected face areas via dedicated clinical scoring systems after a single filler injection without any re-touch or re-injection. The short- and long-term adverse effects were also recorded.

RESULTS

The observations confirmed the non-inferiority of ART FILLER® Volume versus the reference product on the different injected areas. For both fillers, the beneficial effects on volumes restoration were maintained 18 months post-injection; however, these effects were diminished among the time. Furthermore, injections of Art Filler® Volume were well tolerated by the subjects and showed less acute side effects compared with the reference product that may be explained by a lower induction of inflammation.

Application of Nonsurgical Modalities in Improving Facial Aging

Objective. This review aims to summarize different kinds of applications of minimally invasive surgery in improving facial aging to provide a comprehensive and accurate introduction on the issue of esthetic treatment of facial skin. Overview. In the twentieth century, facial rejuvenation has become a new beauty trend. Facial cosmetology has entered a period of antiaging and rejuvenation therapies and microplastic surgery. The pursuit of beauty has promoted the development of minimally invasive plastic surgery. This review introduces the possible causes of facial aging and its related topics with a focus on facial injectable drugs, such as botulinum toxin, main filler materials (hyaluronic acid, calcium hydroxyapatite, poly L-lactic acid, collagen, autologous fat, and polymethyl methacrylate), and some current antiwrinkle technologies, such as thread lift and radiofrequency rhytidectomy. Conclusions. Despite the difference in mechanisms of action, each technique can address facial aging involving the loss of collagen, displacement and enlargement of fat, and muscle relaxation. Combinations of these treatments can provide patients with reasonable, comprehensive, and personalized treatment plans.

A hyaluronic acid-based filler reduces lipolysis in human mature adipocytes and maintains adherence and lipid accumulation of long-term differentiated human preadipocytes

The beneficial role of subcutaneous adipose tissue in skin rejuvenation derived from its capacity to fill the under‐layer volumes but also from its ability to regulate the extracellular matrix production by dermis fibroblasts. Hyaluronic acid (HA), a major component of the extracellular matrix, is a commonly used injectable dermal filler showing excellent efficiencies to maintain tissue augmentation even after its biodegradation. To improve their stability, the HA molecules can also be “cross‐linked” to each other. The effects of cross‐linked HA‐based fillers on the dermal structure are well known. For safety reasons, most of the physicians prefer to use the blunt cannula for injections. However, evidences showed that the cannula could not be located in the dermis, but it passes through immediate hypodermis and the long‐lasting effect of cross‐linked HA‐based fillers may be related to its effects on adipose tissue. To test whether cross‐linked HA has a direct effect on human adipocytes, we treated isolated adipocytes and precursors cells from human skin donors with cross‐linked HA. Biochemical and cellular analysis demonstrated that treatment by cross‐linked HA showed beneficial effects on differentiated cell adherence and survival as well as reduced basal and induced lipolysis in fully mature adipocytes. Taken together, these data showed that cross‐linked HA promoted cell adherence and preserved the adipogenic capacity of preadipocytes during prolonged cell culture, bringing additional evidences of the beneficial role of cross‐linked HA‐based fillers in maintenance of the subcutaneous fat mass. This first study could defend a preventive approach to facial volume loss during natural aging.

Autologous platelet-rich gel for facial rejuvenation and wrinkle amelioration: A pilot study

BACKGROUND

The demand for safe and minimally invasive soft tissue augmentation procedures has increased. Recently, a novel injectable gel based on the autologous platelet rich in growth factor (PRGF) technology has been developed to provide long-term shape and volume stability. It can be customized into low (LVG) or high viscosity (HVG) gel forms to meet different dermatological requirements.

OBJECTIVES

The mechanical and biological properties of both gel forms have been evaluated. The clinical efficacy and safety of this autologous procedure were also evaluated.

METHODS

Growth factor content and biomechanical properties of both gel forms were determined. The in vitro biological capacity on human dermal fibroblasts proliferation was assessed. Clinical performance analysis over ten patients was evaluated by standardized macrophotographs, 3D topographic images, and ultrasound analysis over periocular and nasolabial areas.

RESULTS

Both gel types showed similar growth factor concentration. HVG showed a higher stiffness profile indicating its suitability for deeper tissue defect viscosupplementation while LVG showed optimal rheologic characteristics for superficial volumization. Both gels showed a noticeable biostability after catalytic enzyme degradation. Both forms significantly increased the mitogenic activity of dermal fibroblasts. All patients referred to be highly satisfied and presented optimal clinical results after one month. Overall clinical improvement was maintained for 16 weeks. At the end of the study, the ultrasound examination revealed a cutaneous regenerative effect. No adverse events occurred.

CONCLUSIONS

This preliminary study suggests that autologous platelet gels have desirable mechanical and bioactive properties and allows moderate wrinkle reduction and efficient facial volume reposition with natural results.

Clinical Applications of Hyaluronidase

Hyaluronidases are enzymes that degrade hyaluronic acid, which constitutes an essential part of the extracellular matrix. Initially discovered in bacteria, hyaluronidases are known to be widely distributed in nature and have been found in many classes including insects, snakes, fish and mammals. In the human, six different hyaluronidases, HYAL1-4, HYAL-P1 and PH-20, have been identified. PH-20 exerts the strongest biologic activity, is found in high concentrations in the testicles and can be localized on the head and the acrosome of human spermatozoa. Today, animal-derived bovine or ovine testicular hyaluronidases as well as synthetic hyaluronidases are clinically applied as adjuncts to increase the bioavailability of drugs, for the therapy of extravasations, or for the management of complications associated with the aesthetic injection of hyaluronic acid-based fillers. Further applications in the fields of surgery, aesthetic medicine, immunology, oncology, and many others can be expected for years to come. Here, we give an overview over the molecular and cellular mode of action of hyaluronidase and the hyaluronic acid metabolism, as well as over current and potential future clinical applications of hyaluronidase.

Comparative Evaluation of the Biodegradability and Wrinkle Reduction Efficacy of Human-Derived Collagen Filler and Hyaluronic Acid Filler

BACKGROUND

The development of fillers for wrinkle prevention is growing to meet rising demands to reduce the aging of skin.

OBJECTIVE

In this experiment, we confirmed the effects of human collagen and hyaluronic acid filler biodegradation for wrinkle reduction using a photo-aging mouse model.

MATERIALS AND METHODS

A total of 10 hairless mice (SKH1-Hrhr) were randomly divided into two groups and injected with hyaluronic acid and human-derived collagen filler. At 0, 2, 4, 8, and 12 weeks, PRIMOSlite^®, folliscope, and MRI were used to evaluate the biodegradability of the fillers after the injections. We also studied the photo-aging mouse model for skin roughness and histological evaluation and confirmed that the filler injection had excellent anti-wrinkle effects.

RESULTS

Human-derived collagen fillers had excellent biodegradability compared to that of hyaluronic acid fillers. The skin surface roughness in the photo-aging mouse models was significantly reduced after injections of human-derived collagen filler.

CONCLUSION

Our results showed that the human-derived collagen filler had excellent biodegradability and effectively reduced wrinkle formation in a photo-aging mouse model.

NO LEVEL ASSIGNED

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 .

Redefining face contour with a novel anti-aging cosmetic product: an open-label, prospective clinical study

Background

Skin aging is accelerated by multiple extrinsic factors: ultraviolet radiation, smoking and pollution increase oxidative activity, damaging cellular and extracellular components such as DNA, proteins, and lipids. With age, collagen and hyaluronic acid levels decline, resulting in loss of elasticity and moisture of the skin. Over time this damage leads to characteristic signs that make the skin look older: altered facial contour, sagging skin, wrinkles, and an uneven complexion. This study evaluated the anti-aging effects of a new facial cream formulated with carnosine, Alteromonas ferment extract, crosspolymer hyaluronic acid, and a tripeptide.

Methods

An open-label intra-individual study to assess the anti-aging efficacy of the investigational product in 33 women aged 45 to 65 years. The product was applied twice daily for 56 days. Facial contour and skin deformation, elasticity, hydration, and complexion were measured with specialized equipment at baseline and days 28 and 56. Additionally, subjects completed questionnaires at days 28 and 56 on the perceived efficacy and cosmetic characteristics of the product.

Results

After 56 days of use of the investigational product, a redefining effect was observed, with a significant decrease in sagging jawline (7%). Skin was significantly more hydrated (12%), firmer (29%), and more elastic (20%) (P<0.001 for all). On complexion assessment, skin texture (a measure of skin smoothness) and spots (brown and red skin lesions) also improved significantly (12% and 6% decrease, respectively). In the subjective self-evaluation, the majority of subjects reported that the skin was visibly tightened and more elastic, flexible, and moisturized (91%, 88%, 91%, and 90%, respectively). The product was well tolerated with no adverse events reported during the study.

Conclusion

This new cosmetic product demonstrated anti-aging effects after 56 days of use, most notably a redefined facial contour and improved complexion. It is a safe and effective anti-aging product.

A systematic review of treatments for acne scarring. Part 1: Non-energy-based techniques

Acne is a common condition that can result in permanent scarring. We have performed a comprehensive literature search of the last 10 years in order to determine the efficacy and side effects of commonly used treatments against post-acne scarring. A total of 36 relevant articles were identified on the following interventions: subcision (10), dermabrasion (one), microneedling (eight), dermal fillers (five), and chemical peeling (12). Post acne scarring is a common and challenging condition with no easy and definitive solution. The above interventions have been used with varying degrees of efficacy, each having both pros and cons. All have been deemed to be safe with few and transient adverse reactions. However, further trials with larger number of patients are necessary in order to reach more concrete conclusions regarding their efficacy.

Microscopic and ultrastructural evidences in human skin following calcium hydroxylapatite filler treatment

This study uses light and electron microscopes to gain a better knowledge of the interactions of calcium hydroxylapatite filler with the connective tissue of the skin and the modifications of the human deep dermis, after 2 months of treatment. Some morphological evidences of this observational study of filler treated tissue support-specific mechanism involved in the structural modifications of both filler microspherules and cells of the connective tissue. They demonstrate the absence of any immunological reaction and show that the used filler is modified very slowly over time by the action of cells of the connective tissue closely related to the filler without any activity of phagocytosis. Furthermore, associated with the modifications of the filler, evidences of stimulatory effects on dermal fibroblasts are reported.

Location of injected polymethylmethacrylate microspheres influences the onset of late adverse effects: an experimental and histopathologic study

Polymethylmethacrylate (PMMA) has been widely used in the correction of wrinkles because of its long-lasting cosmetic improvements. However, side effects and complications may occur, and its clinical appearance on the oral mucosa can be similar to that of inflammatory or neoplastic disease. The aim of this research was to compare the clinical and histopathologic responses to PMMA injected by two different methods. Twenty-two rats received an injection of PMMA using the tunneling technique (gold standard), with subcutaneous deposition of the filler in the face, or a variation of the technique with transcutaneous submucosal deposition of the filler in the cheek. The tissue reaction was analyzed clinically every 24 hours during the first week, then once a week for the following 3 months. Histologic evaluation was based on the local inflammatory response to the filler. No clinical changes were observed during the initial evaluation period (0-14 days). After 14 days, only the submucosal group showed extra-oral enlargement (n=4, 18.2%). Histopathologic analysis revealed nodule formation in four animals (18.2%) in the submucosal group, with no nodules observed in the subcutaneous group. The data obtained in this study demonstrate that the technique used to deliver the filler may influence the risk of adverse reactions.

Complications After Facial Injections With Permanent Fillers: Important Limitations and Considerations of MRI Evaluation

BACKGROUND

Soft-tissue fillers have become more prevalent for facial augmentation in the last 2 decades, even though complications of permanent fillers can be challenging to treat. An investigative imaging tool could aid in assessing the nature and extent of these complications when clinical findings are ambiguous.

OBJECTIVES

The authors analyzed the value of magnetic resonance imaging (MRI) in the assessment of delayed-onset complications after injection of patients with permanent fillers.

METHODS

Thirty-two patients with complications related to facial fillers were evaluated in this prospective cohort study. Their medical history was documented, and MRI was conducted before treatment of the complications. Radiologists were informed of the injection sites but were blinded to the results of other clinical evaluations. Levels of agreement between clinical and radiologic findings were calculated with the Jaccard similarity coefficient.

RESULTS

A total of 107 site-specific clinicoradiologic evaluations were analyzed. The level of agreement was assessed as strong for deposits without complications and noninflammatory nodules (combined 85%), moderate for abscesses (60%), fair for low-grade inflammations (32%), and slight for migrations (9%). Results from the MRI examinations aided in subsequent treatment decisions in 11% of cases.

CONCLUSIONS

Study results show that MRI may be useful for diagnosing complications associated with fillers that have migratory potential, for depiction of the extent of deposits before treatment, and for follow-up of low-grade inflammation and abscesses after surgery.

LEVEL OF EVIDENCE

3.

Clinical data on injectable tissue fillers: a review

Treatment with injectable tissue fillers for aesthetic purposes is increasingly popular. In parallel with this success, questions related to the safety of these treatments and the products involved are being raised more prominently. To gain insight in the safety aspects of injectable tissue fillers, we performed a literature review to collect studies reporting clinical data of injectable tissue fillers. We found several case reports where serious complications after more than three years are described. However, there are only a limited number of well-defined prospective clinical studies available with follow-up periods longer than three years. Furthermore, causes of complications, that is, treatment or product related, are often not specified in literature. Considering the intended functional period of fillers in combination with the known occurrence of long-term complications, there is a need for well-defined prospective clinical studies. In order to be able to discriminate between product failure (a product safety issue) or application methodology (a physician expertise or training issue), better identification of observed complications and whether they are product or treatment related, is needed. For the safe use of the fillers it is important that treatment with injectable tissue fillers is performed by a trained physician, who knows the product specifications and its applications.

Inflammatory nodules following soft tissue filler use: a review of causative agents, pathology and treatment options

Nodule development is a common complication following the use of fillers for soft tissue augmentation and is commonly categorized as inflammatory or non-inflammatory in nature. Inflammatory nodules may appear anywhere from days to years after treatment, whereas non-inflammatory nodules are typically seen immediately following implantation and are usually secondary to improper placement of the filler. Although inflammatory nodules are more common with permanent fillers such as silicone, inflammatory nodule development following administration of temporary fillers such as hyaluronic acid and collagen has also been reported. Treated many times with corticosteroids due to their anti-inflammatory properties, inflammatory nodules may be secondary to infection or biofilm formation, warranting the use of alternative agents. Appropriate and prompt diagnosis is important in avoiding delay of treatment or long-term complications for the patient. This paper addresses the etiology, development, and studied treatment options available for inflammatory nodules secondary to each of the major classes of fillers. With this knowledge, practitioners may expeditiously recognize and manage this common side effect and thus maximize functional and aesthetic benefit.

Tissue augmentation with fibrin sealant and cultured fibroblasts: a preliminary study

BACKGROUND

Nonoperative subdermal tissue augmentation is one of the most frequently performed procedures in plastic surgery and dermatological practice. Many products, from biological to synthetic filler substances, are currently available. However, none has achieved ideal clinical efficacy, especially regarding volume maintenance and longevity. We examined the use of fibrin sealant as a biological and fully degradable matrix for dermal augmentation in combination with precultured human fibroblasts and hyaluronic acid gel (HYAFF).

METHODS

Four implant preparations were studied: fibrin glue only (F); 1% HYAFF mixed in fibrin glue (FH); 1.8 × 10(6) cells/ml of fibrin glue (FC); and 1% HYAFF and 1.8 × 10(6) cells/ml of fibrin glue (FHC). Each mouse was given two separate subcutaneous injections of implant material. At 1, 3, and 6 weeks two mice from each group were sacrificed, such that there was an n = 4 for each implant group at each time point. The mice were grossly examined for implant retention and the implants were evaluated by means of immunohistochemistry for fibrosis, integration into surrounding tissue, presence of elastin, and blood vessel infiltration.

RESULTS

Only the implants in the cell-containing groups, FC and FHC, remained after 6 weeks. Moreover, with the exception of a mild inflammatory response, no adverse affects of the cell-seeded implants were noted.

CONCLUSION

Presence of fibroblasts increases implant durability. Further studies should evaluate the ideal hyaluronic acid and fibroblast concentration for long-term longevity.

Optimizing Injectable Poly-L-Lactic Acid Administration for Soft Tissue Augmentation: The Rationale for Three Treatment Sessions

BACKGROUND

The availability and variety of different injectable modalities has led to a dramatic increase in soft tissue augmentation procedures in recent years. Injectable poly-L-lactic acid (PLLA) is a synthetic, biodegradable polymer device approved in the United States for use in immunocompetent patients as a single regimen of up to four treatment sessions for correction of shallow to deep nasolabial fold contour deficiencies and other facial wrinkles. Injectable PLLA is also approved for restoration and/or correction of signs of facial fat loss (lipoatrophy) in individuals with HIV.

METHODS

The present article provides an overview of previous studies with injectable PLLA, and specifically focuses on the number of recommended treatment sessions and intervals between treatment sessions. The authors also provide two case studies to support their recommendations for an average of three treatment sessions.

RESULTS

Although the specific mechanisms remain hypothetical, injections of PLLA are believed to cause a cascade of cellular events that lead to collagen repair and subsequent restoration of facial volume. Because the development of a response to injectable PLLA is gradual and its duration of effect is long lasting, sufficient time between treatment sessions should be allocated to avoid overcorrection.

CONCLUSION

Studies of injectable PLLA support the hypothesized mode of operation, and the experience and clinical recommendations of the authors that suggest that three treatment sessions are an optimal regimen for use of injectable PLLA in the majority of patients.

Safety and persistence of non-animal stabilized hyaluronic Acid fillers for nasolabial folds correction in 30 Indian patients

BACKGROUND

Correction of nasolabial creases through minimally invasive procedures is increasingly being sought by patients. Injecting non-animal stabilized hyaluronic acid filler is a highly effective method to achieve an optimal and persistent cosmetic result

AIMS

To evaluate the efficacy, persistence and safety of Restylane and Perlane (Q-Med, Sweden) for correction of nasolabial folds in Indian patients

MATERIALS AND METHODS

Thirty Indian patients with mild, moderate and severe nasolabial folds (based on Wrinkle Assessment Scale) were recruited in the study after informed consent for correction of their folds with Restylane or Perlane or both. Injections were administered in a single sitting after global assessment of the patient's face using Wrinkle assessment scale (WAS).Optimal filling was performed by using appropriate techniques and its safety and efficacy assessed independently by the investigator as well as by patients at immediately, 3, 6 and 9 months post-procedure. Any adverse reactions were noted.

RESULTS

Twenty two females and 8 males (age range 45-55 years, mean age 52 years) were recruited in the study. An optimum cosmetic correction was obtained in all patients. The efficacy increased with time and was greatest at 3 months after the treatment. Grade 2 improvement was maintained at 9 months in mild and moderate folds, and grade 3 improvement for severe folds. Minor post injection side effects like erythema at puncture site, needle marks and bruising were seen.

CONCLUSION

Restylane and Perlane are safe and effective dermal fillers for correction of nasolabial creases and offer immediate effect.

Complications related to Artecoll injections for soft tissue augmentation of the hand: 3 case reports

Rejuvenation of the aging hand has gained recent popularity. I report on 3 cases with complications related to the use of Artecoll (a permanent filler composed of polymethylmethacrylate) in soft tissue augmentation of the hand. All 3 patients had late-onset granuloma reactions, and the acute attacks were successfully treated with local injections of triamcinolone. However, recurrent reactions and hypopigmentation at the injection sites were noted.

Etiology, prevention, and treatment of dermal filler complications

The availability of dermal fillers for multiple cosmetic indications has led to a dramatic increase in their application. Although fillers are generally regarded as safe tools for soft tissue augmentation, complications can occur. Therefore, to describe and review the complications associated with the currently-available dermal filling agents, the authors conducted a literature review in peer-reviewed journals and present the reported complication rates. They also describe current strategies to avoid, diagnose, and manage complications if they do occur.

Counseling patients on facial volume replacement and adherence with posttreatment instructions

Use of injectable volume replacement products has increased dramatically in the US in recent years. An optimal outcome with volume replacement depends on a thorough knowledge of the products on the part of the dermatologic/aesthetic physician specialist, identification of patients with a likelihood of benefiting from volume replacement procedures, selection of an appropriate product for the individual patient, and effective patient counseling to ensure adherence to posttreatment care instructions. Adherence to physician instructions in the field of dermatology appears limited, and there is very little published information on adherence to physician instructions following facial volume replacement procedures. The purpose of this review is to provide strategies for understanding and overcoming the barriers to adherence with the widely used dermal fillers. Strategies include using patient-centered techniques, such as a motivational interview encouraging the patient to follow postprocedure care instructions, eg, massage. In this case, demonstrating massage techniques while the patient is still in the office, with patient participation and detailed feedback, also contributes to good adherence with posttreatment care instructions. Telephone counseling, reminder postcards, and text messages may help improve clinic attendance for follow-up. Motivated patients who demonstrate good adherence to physician instructions generally respond well to volume replacement treatments, and usually experience fewer adverse events than patients who do not follow instructions. Although promoting adherence to pretreatment and posttreatment protocols remains a challenge, patient counseling throughout the treatment process can lead to successful results.

Update on botulinum toxin and dermal fillers

PURPOSE OF REVIEW

The art and science of facial rejuvenation is an ever-evolving field of medicine, as evidenced by the continual development of new surgical and nonsurgical treatment modalities. Over the past 10 years, the use of botulinum toxin and dermal fillers for aesthetic purposes has risen sharply. Herein, we discuss properties of several commonly used injectable products and provide basic instruction for their use toward the goal of achieving facial rejuvenation.

RECENT FINDINGS

The demand for nonsurgical injection-based facial rejuvenation products has risen enormously in recent years. Used independently or concurrently, botulinum toxin and dermal filler agents offer an affordable, minimally invasive approach to facial rejuvenation.

SUMMARY

Botulinum toxin and dermal fillers can be used to diminish facial rhytides, restore facial volume, and sculpt facial contours, thereby achieving an aesthetically pleasing, youthful facial appearance.

Cross-linked hyaluronan gel reduces the acute rectal toxicity of radiotherapy for prostate cancer

PURPOSE

To prospectively analyze whether cross-linked hyaluronan gel reduces the mean rectal dose and acute rectal toxicity of radiotherapy for prostate cancer.

METHODS AND MATERIALS

Between September 2008 and March 2009, we transperitoneally injected 9 mL of cross-linked hyaluronan gel (Hylaform; Genzyme Corporation, Cambridge, MA) into the anterior perirectal fat of 10 early-stage prostate cancer patients to increase the separation between the prostate and rectum by 8 to 18 mm at the start of radiotherapy. Patients then underwent high-dose rate brachytherapy to 2,200 cGy followed by intensity-modulated radiation therapy to 5,040 cGy. We assessed acute rectal toxicity using the National Cancer Institute Common Terminology Criteria for Adverse Events v3.0 grading scheme.

RESULTS

Median follow-up was 3 months. The anteroposterior dimensions of Hylaform at the start and end of radiotherapy were 13 +/- 3mm (mean +/- SD) and 10 +/- 4mm, respectively. At the start of intensity-modulated radiation therapy, daily mean rectal doses were 73 +/- 13 cGy with Hylaform vs. 106 +/- 20 cGy without Hylaform (p = 0.005). There was a 0% incidence of National Cancer Institute Common Terminology Criteria for Adverse Events v3.0 Grade 1, 2, or 3 acute diarrhea in 10 patients who received Hylaform vs. a 29.7% incidence (n = 71) in 239 historical controls who did not receive Hylaform (p = 0.04).

CONCLUSIONS

By increasing the separation between the prostate and rectum, Hylaform decreased the mean rectal dose. This led to a significant reduction in the acute rectal toxicity of radiotherapy for prostate cancer.

In vivo osteogenic differentiation of human adipose-derived stem cells in an injectable in situ-forming gel scaffold

The sol-to-gel transition occurring at around body temperature makes the MPEG-PCL diblock copolymer an ideal candidate material for use as an injectable in situ-forming gel containing human adipose tissue-derived stem cells (hADSCs). The sol can be prepared at room temperature, and the gel forms at body temperature. Solutions of the copolymer containing hADSCs and osteogenic factors injected into rats formed gel scaffolds at the injection sites. The gels thus formed showed the interconnective pore structure required to support growth, proliferation, and differentiation of hADSCs. Bromodeoxyuridine-labeled hADSCs were confirmed to be present in gels formed in vivo. Bone formation was observed only in gel implants containing both hADSCs and osteogenic factors. Subcutaneous implantation of the in situ-forming gel scaffold demonstrated that hADSCs embedded in the gel stimulated much lower host tissue responses than did the gel alone, probably because of the unique immunomodulatory properties of hADSCs. In conclusion, our data on hADSCs embedded in an in situ gel scaffold suggest that this formulation may provide numerous benefits as a noninvasive alternative for tissue-engineered bone formation.

[Fillers. An overview]

The demand for minimally invasive cosmetic procedures is increasing rapidly every year. In addition to botulinum toxin and laser treatments, the injection of dermal fillers is one of the most relevant methods. Dermal fillers can be used for a multitude of indications: wrinkles (fine to deep), lip augmentation, facial deformities, sunken scars, and HIV-related lipoatrophy in hands, neck and décolleté. There are currently 160 dermal fillers on the market. They differ greatly in terms of origin (own or cadaveric-derived, animal, bacterial fermentation or synthesis), duration of the effect and breakdown properties (temporary, semi-permanent, permanent), injection depth (dermal, subcutaneous, supraperiosteal), and risk profile. Physicians who administer dermal fillers should have a thorough knowledge of their characteristics and of the anatomy of the area to be treated. This is essential for correct administration and optimal aesthetic results. Prior to any treatment, details of the procedure, the desired effects, durability, and potential risks of the filler to be injected should be discussed with the patient. The choice of dermal filler, the injection technique, and the volume to be administered are determined according to the anatomic site, the type of defect, the desired effect, and physician experience.

Tissue integration of polyacrylamide hydrogel: an experimental study of periurethral, perivesical, and mammary gland tissue in the pig

BACKGROUND Polyacrylamide hydrogel (PAAG) is a nondegradable water-based polymer with high viscoelasticity. The gel is used as a tissue filler, the only risk being prolonged infection with anaerobic, contaminating microorganisms if not treated early with broad-spectrum antibiotics. OBJECTIVE With silicone gel as reference, PAAG tissue integration and migration was studied in a longitudinal study of the pig. MATERIALS AND METHODS Forty-one pigs were used. PAAG and silicone gel were injected into mammary tissue, and PAAG was injected into urethral or bladder wall or the anal canal. Tissues and regional lymph nodes were examined at 1, 1(1/2), 3, 3(1/2), 6, 12, and 14 months, and other lymph nodes and organs were examined at 1, 6, 12, and 14 months. RESULTS PAAG was invaded by macrophages and giant cells that were gradually replaced by a network of fibrous tissue. Silicone gel was seen inside these cells or as large vacuoles, surrounded by a fibrous capsule. Regional lymph nodes contained PAAG only at 1 1/2 months and silicone gel at 12 months. CONCLUSION PAAG is a stable, viscoelastic bulking agent, which unlike silicone gel is slowly integrated within its host tissue via a thin fibrous network. Long-term risk of fibrosis and migration is minimal.

Use of calcium hydroxylapatite (Radiesse) for facial augmentation

Radiesse^® (Bioform Inc, USA) is a sterile, latex-free, non-pyrogenic, semi-solid, cohesive subdermal, injectable implant, whose principal component is synthetic calcium hydroxylapatite, a biocompatible material with over 20 years of use in medicine. The semi-solid nature of the product is created by suspending calcium hydroxylapatite microspheres of 25–45 microns diameter in a gel carrier of carboxymethylcellulose. The product has FDA approval for esthetic facial augmentation in the US. Such approval includes the long-lasting correction of moderate to severe facial wrinkles and folds and the treatment of facial fat loss due to immunodeficiency virus infection. Diverse facial regions can be injected in order to ameliorate or enhance some features: glabellar lines, subdermal support of the brows, malar and buccal fat pads, tear troughs, nasolabial folds, nose, lips, perioral region, marionette lines, oral commisures and chin among others, as well as saucerized acne scars. Other medical indications include nipple projection for nipple areolar reconstruction, urinary incontinence, vesicoureteral reflux, vocal cord augmentation, and use as a radiographic tissue marker. The average lasting result is from 12 to 18 months. Radiesse can be considered an effective soft-tissue filler for overall longevity, biocompatibility, and low rate of side effects.