Safety and efficacy of a carboxymethyl chitosan dermal injection device for the treatment of skin defects: a first-in-man, pilot, comparative, split-body study.

Injectable soft-tissue devices are increasingly used for improving skin defects and deficiencies related to ageing. To assess the safety and efficacy of KIO015, a new injectable soft-tissue device formulated with carboxymethyl chitosan for the intradermal treatment of skin defects associated with ageing. Twenty-two subjects (40-65 years) were randomized to receive injections in the neckline of KIO015 and a non-cross-linked HA-based device, and were followed for up to 10 months. Injection site reactions (ISRs) and adverse events (AEs) were documented. Skin improvement was assessed instrumentally and clinically. Skin biopsies at injection zones in the lower back were taken at Day 28 for histopathology and immunohistochemistry analyses, to further assess product performance. Histomorphometric analyses on rabbits and in vitro assessment of KIO015 antioxidant capacity were also conducted. KIO015 was very well tolerated. Only expected and transient ISRs were observed; mainly erythema and hematoma. No adverse local effects or foreign body granuloma were observed histologically. Both clinical and instrumental evaluations confirmed the performance of KIO015. The skin was firmer and more elastic. Skin hydration showed significant improvement three days after injection. KIO015 exhibited superior overall maintenance of skin hydration after 10 months as compared to HA. These clinical results were supported by in vitro trials and implantation tests in the rabbit. The results from this pilot study support the use of KIO015 as an innovative alternative to HA-based devices for intradermal treatment of skin disorders.

Spreading Pattern and Tissue Response to Hyaluronic Acid Gel Injections in the Subcutis: Ultrasound Videos, Ultrasound Measurements, and Histology.

BACKGROUND: Despite the popularity of hyaluronic acid (HA) filler treatments, few publications focus on their effects on adipose tissue. OBJECTIVES: The authors assessed the deposition pattern in the subcutis of injected HA, the tissue response at short and intermediate term, and the effects of remodeling the filler by strong finger pressure immediately after the treatment. METHODS: Two brands, specifically developed by the industry for deep injection, were compared. The gels were injected subcutaneously in 5 candidates for abdominoplasty or breast reduction, in the area of excision, 6 to 98 days before surgery. Ultrasound measurements and films were compared with postoperative histological findings. Tissue response was scored semi-quantitatively. RESULTS: Real-time ultrasound showed a slightly different deposition pattern of the 2 brands. Histologically, both were present in large pools of the same magnitude and looked the same. Linear retrograde injection sometimes resulted in a globular deposit due to elastic recoil of septae. After remodeling and over time, HA deposits became difficult to detect by ultrasound. Firm remodeling of the tissue immediately after injection or time had no significant effect on filler spread or tissue response. Except for 1 zone of granuloma formation, tolerance for both fillers was good. CONCLUSIONS: HA deposition in adipose tissue occurs in much larger pools than in the dermis. Ultrasound examination is useful during and immediately after the injection but less reliable after filler remodeling or over time. Filler deposition can be less precise, and reshaping by finger pressure can have less effect than expected.

Hyaluronic Acid After Subcutaneous Injection-An Objective Assessment.

BACKGROUND: Hyaluronic acid (HA) fillers are the preferred injectable products for aesthetic correction of skin depressions and restoration of facial volume. OBJECTIVE: To investigate the subcutaneous distribution of 3, biophysically distinct, CE-marked and FDA-approved HA fillers. MATERIALS AND METHODS: BELB, JUVV, and RESL were injected ex vivo in porcine and human skin. Immediately after injection, the skin samples were snap-frozen, cross-sectioned, and visualized using stereomicroscopy and full-field optical coherence tomography. Images were compared with histological sections after hematoxylin and eosin staining. RESULTS: Hyaluronic acid fillers were distributed as homogeneous bolus in the ex vivo skin. The injection bulks were found to preserve the fibrous trabecular network, shift the fat lobules, and displace the adjacent adipocyte layers independently of the formulation injected. CONCLUSION: For the first time, the subcutaneous injection of 3 HA fillers with markedly different biophysical properties was systematically investigated by complementary visualization techniques. Despite their different properties, no difference in distribution was found after subcutaneous injection. The global preservation of the hypodermis structure observed was consistent with the good tolerability seen in clinical practice after implantation of the HA fillers in the subcutaneous skin layer.

Injection Depth in Intradermal Therapy: Update and Correction of Published Data.

BACKGROUND: This paper sought to compare calculated injection depth data with published report claims concerning intradermal therapy and skin rejuvenation of the face, hands, neck, and décolleté. OBJECTIVE: A mathematical formula was employed to assess the injection depth, and data from literature were retrieved and compared with the calculated figures to determine whether the claims about the injection depth proved correct. METHODS: Based on a study by Della Volpe et al., involving 140 skin residues adapted for plastic surgery, we have calculated injection depths from published reports on intradermal therapy and skin rejuvenation while comparing these figures with the published injection depth claims. RESULTS: Most injections were not performed at the claimed depth, with over 70% of them carried out in the fat layer, thus, the hypodermis. This is not the recommended depth for a refined injection technique in the intradermal therapy field. CONCLUSION: Whilst examining our study results, two different possibilities come to mind. We must either: 1) review and correct the existing histological classification; and/or 2) better learn to correctly inject in the superficial-dermis, mid-dermis, and deep-dermis. In other words, a perfect control over the needle penetration angle and implanted part appears urgently required.

J Drugs Dermatol. 2018;17(1):89-96.

Ultrasound and Histologic Examination after Subcutaneous Injection of Two Volumizing Hyaluronic Acid Fillers: A Preliminary Study.

BACKGROUND: This study examined the influence of hyaluronic acid (HA) crosslinking technology on the ultrasound and histologic behavior of HA fillers designed for subcutaneous injection. METHODS: One subject received subcutaneous injections of 0.25 ml Cohesive Polydensified Matrix (CPM) and Vycross volumizing HA in tissue scheduled for abdominoplasty by bolus and retrograde fanning techniques. Ultrasound analyses were performed on days 0 and 8 and histologic analyses on days 0 and 21 after injection. A series of simple rheologic tests was also performed. RESULTS: Day 0 ultrasound images after bolus injection showed CPM and Vycross as hypoechogenic papules in the hypodermis. CPM appeared little changed after gentle massage, whereas Vycross appeared more hyperechogenic and diminished in size. Ultrasound images at day 8 were similar. On day 0, both gels appeared less hypoechogenic after retrograde fanning than after bolus injection. Vycross was interspersed with hyperechogenic areas (fibrous septa from the fat network structure) and unlike CPM became almost completely invisible after gentle massage. On day 8, CPM appeared as a hypoechogenic pool and Vycross as a long, thin rod. Day 0 histologic findings confirmed ultrasound results. Day 21 CPM histologic findings showed a discrete inflammatory reaction along the injection row after retrograde fanning. Vycross had a more pronounced inflammatory reaction, particularly after retrograde fanning, with macrophages and giant cells surrounding the implant. Rheologic tests showed CPM to have greater cohesivity and resistance to traction forces than Vycross. CONCLUSIONS: CPM HA volumizer appears to maintain greater tissue integrity than Vycross after subcutaneous injection with less inflammatory activity.

Two Crosslinking Technologies for Superficial Reticular Dermis Injection: A Comparative Ultrasound and Histologic Study.

Background: Few hyaluronic acid fillers have been developed for superficial injection. Objective: To compare the diffusion and integration properties of cohesive polydensified matrix and Vycross® technology hyaluronic acid fillers with lidocaine following injection into the superficial reticular dermis. Methods and materials: Two subjects received two injections each of cohesive polydensified matrix and Vycross® hyaluronic acid (0.2mL/site) in the superficial reticular dermis of the buttock under ultrasound control. Biopsies were obtained at Days 0, 15, and/or 90. Ultrasound and histologic analyses were performed, plus a series of simple rheological tests. Results: Day 0 ultrasound images showed cohesive polydensified matrix hyaluronic acid homogeneous with the surrounding dermis. Vycross® hyaluronic acid showed more heterogeneity and some leakage into the hypodermis. Day 15 and Day 90 images were similar to Day 0. Histologic examination of biopsy tissue showed cohesive polydensified matrix hyaluronic acid homogeneously distributed among collagen fibrils with no visible particles. Vycross® hyaluronic acid appeared as variable-sized pools with a particulate appearance. Neither gel was associated with an inflammatory reaction. Laboratory tests showed cohesive polydensified matrix hyaluronic acid to have greater cohesivity and resistance to traction forces than Vycross®. Conclusion: cohesive polydensified matrix gel with lidocaine is homogeneously distributed following injection in the superficial reticular dermis and may be particularly suited for aesthetic indications requiring superficial injection.

In vivo bio-integration of three hyaluronic acid fillers in human skin: a histological study.

BACKGROUND: Hyaluronic acid (HA) formulations are used for aesthetic applications. Different cross-linking technologies result in HA dermal fillers with specific characteristic visco-elastic properties. OBJECTIVE: Bio-integration of three CE-marked HA dermal fillers, a cohesive (monophasic) polydensified, a cohesive (monophasic) monodensified and a non-cohesive (biphasic) filler, was analysed with a follow-up of 114 days after injection. Our aim was to study the tolerability and inflammatory response of these fillers, their patterns of distribution in the dermis, and influence on tissue integrity. METHODS: Three HA formulations were injected intradermally into the iliac crest region in 15 subjects. Tissue samples were analysed after 8 and 114 days by histology and immunohistochemistry, and visualized using optical and transmission electron microscopy. RESULTS: Histological results demonstrated that the tested HA fillers showed specific characteristic bio-integration patterns in the reticular dermis. Observations under the optical and electron microscopes revealed morphological conservation of cutaneous structures. Immunohistochemical results confirmed absence of inflammation, immune response and granuloma. CONCLUSION: The three tested dermal fillers show an excellent tolerability and preservation of the dermal cells and matrix components. Their tissue integration was dependent on their visco-elastic properties. The cohesive polydensified filler showed the most homogeneous integration with an optimal spreading within the reticular dermis, which is achieved by filling even the smallest spaces between collagen bundles and elastin fibrils, while preserving the structural integrity of the latter. Absence of adverse reactions confirms safety of the tested HA dermal fillers.

A blanching technique for intradermal injection of the hyaluronic acid Belotero.

With the proliferation of dermal fillers in the aesthetic workplace have come instructions from various manufacturers regarding dermal placement. Determination of injection needle location in the dermis has in large part been based on physician expertise, product and needle familiarity, and patient-specific skin characteristics. An understanding of the precise depth of dermal structures may help practitioners improve injection specificity. Unlike other dermal fillers that suggest intradermal and deep dermal injection planes, a new hyaluronic acid with a cohesive polydensified matrix may be more appropriate for the superficial dermis because of its structure and its high degree of integration into the dermis. To that end, the authors designed a small study to quantify the depth of the superficial dermis by means of ultrasound and histology. Using ultrasound resources, the authors determined the depths of the epidermis, the dermis, and the reticular dermis in the buttocks of six patients; the authors then extrapolated the depth of the superficial reticular dermis. Histologic studies of two of the patients showed full integration of the product in the reticular dermis. Following determination of injection depths and filler integration, the authors describe a technique ("blanching") for injection of the cohesive polydensified matrix hyaluronic acid into the superficial dermis. At this time, blanching is appropriate only for injection of the cohesive polydensified matrix hyaluronic acid known as Belotero Balance in the United States, although it may have applications for other hyaluronic acid products outside of the United States.

Superficial dermal injection of hyaluronic acid soft tissue fillers: comparative ultrasound study.

BACKGROUND: Superficial dermal injection of hyaluronic acids (HAs) has not been well studied. OBJECTIVES: To study HAs injected into the superficial dermis using ultrasound examination and measurements, to evaluate induration and pain, and to examine histology. MATERIALS AND METHODS: Three commercial HAs were injected into the superficial dermis (0.2 mL). The HAs used were a biphasic gel, a monophasic monodensified gel, and a monophasic polydensified gel. Ultrasound measurements and images were obtained, pain assessed, and biopsies performed at 7 days. RESULTS: Participants experienced pain from the HAs that did not contain lidocaine. After 8 days, the biphasic HA papules appeared erythematous, with two-thirds reporting the biphasic HA papules as tender. Ultrasound demonstrated superficial placement of HA gels in the upper dermis. The gels each exhibited unique characteristic patterns on ultrasound. Skin biopsies of the superficial dermal placement confirmed earlier patterns. Superficial placement of the biphasic product is associated with tenderness and an eosinophilic inflammatory infiltrate. CONCLUSION: Superficial placement of HAs is possible, as demonstrated by ultrasonography. Gels that do not have lidocaine within them are more painful. Injection of biphasic HA gels superficially in the dermis is associated with clinical erythema and tenderness and histology showing an eosinophilic infiltrate.

Hyaluronan and the "mushroom" technique: an assessment of hyaluronan injections into the glans.

BACKGROUND: An Asian technique of injecting collagen below the corona of the glans-the "mushroom" technique-increases the diameter of the penis glans and heightens sexual sensations for the participant and his sexual partner. OBJECTIVES: To improve the physical and aesthetic results of the "mushroom" technique-compared with previous procedures using collagen-by using a new material and alternative injection locations and patterns. MATERIALS AND METHODS: The team used a monophasic polydensified hyaluronan (HA) gel for superficial injection into the glans of 12 men aged 28 to 61. Local anesthetic was applied, and one of three injection patterns was tried. Participants self-assessed efficacy and pre- versus postinjection sensitivity using a visual analogue scale and a multiple-choice questionnaire. RESULTS: All participants experienced heightened levels of sensation and increased glans diameter. The hyaluronan gel was well tolerated. Of the three injection patterns tested, one (retrograde contiguous injection) was found to be an improvement over the "mushroom" injection protocol. CONCLUSIONS: Injection directly into the glans increases its diameter when the penis is erect, and heightens sexual sensations. The monophasic and polydensified hyaluronan gels are suitable alternatives to collagen.

Comparative histology of intradermal implantation of mono and biphasic hyaluronic acid fillers.

BACKGROUND: Hyaluronic acid (HA) gels have been used as filler material in the aesthetic field. Although the native HA molecule is without specificity of species and organs, synthetic cross-linked gels have differences in chemical composition and three-dimensional structure. Different technologies are employed in cross-linking, and the products have varying rheological properties. OBJECTIVE: To determine whether the gels with differing chemical composition have differing histologic behavior when injected into human skin to determine if the histology changes after 14 days of implantation. MATERIALS AND METHODS: Human volunteers consented to having controlled placement of HA intradermally into forearm or buttock skin. The trials were conducted in a single clinic in association with the Hôpitaux Universitaires de Genève, Geneva, Switzerland. The biopsies were taken immediately after implantation of the product and at day 14. Standard paraffin sections were prepared and stained with hematoxylin and eosin and Alcian blue and examined by an independent pathologist. RESULTS: Results show that each type of HA has a predictable histologic behavior in the skin. Biphasic gel has demonstrated deposition in big pools, often deep in the reticular dermis. The pools compress the collagen fibers. The papillary dermis and superficial reticular dermis are free of HA. Monophasic monodensified gels show large pools of hyaluronans throughout all the thickness of the reticular dermis. This material breaks up the collagen fibers of most of the dermal plane. The papillary dermis is free of exogenous hyaluronans. Monophasic polydensified cohesive gel penetrates into the dermis in a diffuse, evenly distributed manner, except in the papillary dermis, which remains free of exogenous material. CONCLUSION: The different types of cross-linked HA have different behaviors in the dermis immediately after their injection. The patterns are consistent between patients and are predictable. These histologic patterns do not change when biopsies are examined at 2 weeks.