Standardizing Dimensionless Cutometer Parameters to Determine In Vivo Elasticity of Human Skin

Development and characterization of an emulgel based on a snail slime useful for dermatological applications

Snail slime is an interesting material for effective dermatological use (e.g. wounds). Its properties are stricly connected to the origin. In this paper a snail slime, deriving from the species Helix aspersa Muller and obtained from a company, was deeply characterized and then properly formulated. The slime, obtained by Donatella Veroni method, was firstly submitted to NMR analysis in order to evaluate the chemical composition. The main molecules found are glycolate and allantoin, well known for their activities in wound healing promotion. In vitro experiments performed on keratinocytes, revealed the snail slime ability to promote cellular well-being. Moreover, the microbiological analysis showed high activity against many strains involved in wounds infections such as gram+ (e.g. S. aureus, S. pyogenes), gram- (e.g. P. aeruginosa, E. coli) and the yeast C. albicans. The effect on skin elasticity was evaluated as well by the instrument Cutometer® dualMPA580. The snail slime was then formulated as hydrophilic gel, using a combination of corn starch and sodium hyaluronate as polymers, then used as external water phase of an O/W emulgel. The formulation is physically stable and easily spreadable and demonstrated antimicrobial activity as observed for slime alone, suggesting its suitability to be used for wound treatment.

The WD Domain of Atg16l1 Crucial for LC3-Associated Phagocytosis Is Not Required for Preserving Skin Barrier Function in Mice

The skin is a multifunctional organ, forming a barrier between the external and internal environment, thereby functioning as a safeguard against extrinsic factors. Autophagy has been implicated in epidermal differentiation and in preserving skin homeostasis. LC3-associated phagocytosis (LAP) uses some but not all components of autophagy. The Atg16l1 (Δ WD) mouse model lacks the WD40 domain required for LAP and has been widely used to study the effects of LAP deficiency and autophagy on tissue homeostasis and response to infection. In this study, the Δ WD model was used to study the relationship between LAP and skin homeostasis by determining whether LAP-deficient mice display a cutaneous phenotype. Skin histology of wild-type and Δ WD mice aged 1 year revealed minor morphological differences in the tail skin dermal layer. RT-qPCR and western blot analysis showed no differences in key keratin expression between genotypes. Skin barrier formation, assessed by dye permeation assays, demonstrated full and proper formation of the skin barrier at embryonic day 18.5 in both genotypes. Biomechanical analysis of the skin showed decreased skin elasticity in aged Δ WD but not wild-type mice. In summary, the LAP-deficient Δ WD mice displayed subtle alterations in dermal histology and age-related biomechanical changes.

Deferoxamine topical cream superior to patch in rescuing radiation-induced fibrosis of unwounded and wounded skin

Topical patch delivery of deferoxamine (DFO) has been studied as a treatment for this fibrotic transformation in irradiated tissue. Efficacy of a novel cream formulation of DFO was studied as a RIF therapeutic in unwounded and excisionally wounded irradiated skin. C57BL/6J mice underwent 30 Gy of radiation to the dorsum followed by 4 weeks of recovery. In a first experiment, mice were separated into six conditions: DFO 50 mg cream (D50), DFO 100 mg cream (D100), soluble DFO injections (DI), DFO 1 mg patch (DP), control cream (Vehicle), and irradiated untreated skin (IR). In a second experiment, excisional wounds were created on the irradiated dorsum of mice and then divided into four treatment groups: DFO 100 mg Cream (W-D100), DFO 1 mg patch (W-DP), control cream (W-Vehicle), and irradiated untreated wounds (W-IR). Laser Doppler perfusion scans, biomechanical testing, and histological analysis were performed. In irradiated skin, D100 improved perfusion compared to D50 or DP. Both D100 and DP enhanced dermal characteristics, including thickness, collagen density and 8-isoprostane staining compared to untreated irradiated skin. D100 outperformed DP in CD31 staining, indicating higher vascular density. Extracellular matrix features of D100 and DP resembled normal skin more closely than DI or control. In radiated excisional wounds, D100 facilitated faster wound healing and increased perfusion compared to DP. The 100 mg DFO cream formulation rescued RIF of unwounded irradiated skin and improved excisional wound healing in murine skin relative to patch delivery of DFO.

Evaluation of Esthetic Results after Mass Removal with Elliptical Skin Excision Using Ultrasonography to Measure Skin Thickness

Background: The growth of benign cutaneous masses causes the overlaying skin to expand and become thinner, especially at the central, most projected point. In this retrospective study, a surgical technique comprising an elliptical skin excision was employed to account for these skin changes. Methods: This retrospective study enrolled 980 patients with benign masses. Preoperatively, all patients underwent ultrasonography to evaluate the mass depth and thickness of the attached skin, and mass excision was performed using the elliptical skin-excision method. The operative time was recorded, and complications and esthetic outcomes were assessed using the Cutometer® and the modified Vancouver Scar Scale (mVSS) during 1- and 3-month follow-up visits. Results: The mean operative time (17.48 ± 3.46 min) was significantly shorter than that of conventional methods (p < 0.05). Cutometer parameters showed no significant differences from those of intact skin. The average mVSS scores were 5.21 ± 1.42 and 3.50 ± 1.79 at 1- and 3-month follow-ups, respectively. Conclusions: Mass excision with an elliptical skin attachment resulted in improved esthetic results and easy removal. The attached skin enabled convenient handling without damaging the capsule or other adjacent structures, leaving a thick dermis on both wound edges. Thus, this technique resulted in minimal scarring.

Correlation analysis between texture features and elasticity of skin hyperspectral images in the near-infrared band

BACKGROUND/PURPOSE

Skin elasticity was used to evaluate healthy and diseased skin. Correlation analysis between image texture characteristics and skin elasticity was performed to study the feasibility of assessing skin elasticity using a non-contact method.

MATERIALS AND METHODS

Skin images in the near-infrared band were acquired using a hyperspectral camera, and skin elasticity was obtained using a skin elastimeter. Texture features of the mean, standard deviation, entropy, contrast, correlation, homogeneity, and energy were extracted from the acquired skin images, and a correlation analysis with skin elasticity was performed.

RESULTS

The texture features, and skin elasticity of skin images in the near-infrared band had the highest correlation on the side of eye and under of arm, and the mean and correlation were features of texture suitable for distinguishing skin elasticity according to the body part.

CONCLUSION

In this study, we performed elasticity and correlation analyses for various body parts using the texture characteristics of skin hyperspectral images in the near-infrared band, confirming a significant correlation in some body parts. It is expected that this will be used as a cornerstone of skin elasticity evaluation research using non-contact methods.

Gold nanobipyramids-based laser-activated sealants for effective skin sealing and repair

Anisotropic gold nanostructures have gained increased attention for biomedical applications because of their remarkable optical properties. An emerging type of gold nanostructure-gold nanobipyramids (AuNBP)-has been shown to exhibit superior absorption properties compared to conventionally used gold nanoparticles, which makes them attractive for photothermal applications. We generated a high-shape-purity dispersion of AuNBP using a seed-mediated method and embedded them as photothermal conversion agents in a silk fibroin matrix to investigate their efficacy in photothermal sealing of incisional wounds in immunocompetent mice. These AuNBP-doped laser-activated sealants, or AuNBP-LASE were able to absorb near-infrared laser energy and convert it to heat, thereby inducing transient hyperthermia in the wound and the surrounding tissue. This photothermal conversion facilitated rapid sealing of the skin tissue by the AuNBP-LASE, which resulted in faster functional recovery of skin barrier function compared to nylon sutures at the early stages of repair. Further, the biomechanical properties of the healing skin closed with AuNBP-LASE those of intact skin more rapidly compared to incisions approximated with sutures. Histology studies indicated higher penetration of the LASE within the volume of the incision in skin tissue, lower scab formation, and a similar epidermal gap compared to conventional suturing. These results demonstrate that AuNBP-LASEs can be effective as wound approximation devices for photothermal sealing.

Genetic background determines severity of Loxl1-mediated systemic and ocular elastosis in mice

Pseudoexfoliation syndrome (PEX) is a systemic, age-related disorder characterized by elastosis and extracellular matrix deposits. Its most significant ocular manifestation is an aggressive form of glaucoma associated with variants in the gene encoding lysyl oxidase-like 1 (LOXL1). Depending upon the population, variants in LOXL1 can impart risk or protection for PEX, suggesting the importance of genetic context. As LOXL1 protein levels are lower and the degree of elastosis is higher in people with PEX, we studied Loxl1-deficient mice on three different genetic backgrounds: C57BL/6 (BL/6), 129S×C57BL/6 (50/50) and 129S. Early onset and high prevalence of spontaneous pelvic organ prolapse in BL/6 Loxl1-/- mice necessitated the study of mice that were <2 months old. Similar to pelvic organ prolapse, most elastosis endpoints were the most severe in BL/6 Loxl1-/- mice, including skin laxity, pulmonary tropoelastin accumulation, expansion of Schlemm's canal and dilation of intrascleral veins. Interestingly, intraocular pressure was elevated in 50/50 Loxl1-/- mice, depressed in BL/6 Loxl1-/- mice and unchanged in 129S Loxl1-/- mice compared to that of control littermates. Overall, the 129S background was protective against most elastosis phenotypes studied. Thus, repair of elastin-containing tissues is impacted by the abundance of LOXL1 and genetic context in young animals.

Treatment of Stretch Marks Using a New Formulation Combining Nanofractional Radiofrequency Plus Magnetic Nanofractional Radiofrequency

INTRODUCTION

Stretch marks are common atrophic dermal scars with significant physical and psychological effects. Therefore, there is a need for effective cosmetics and procedures for stretch mark treatment. This study aimed to evaluate the efficacy and safety of a novel treatment for stretch marks that is made up of topical formulations containing beta-glucan combined with nanofractional radiofrequency.

METHODS

This randomized, blinded control trial enrolled 64 Chinese women aged 20-45 years at > 6 months after delivery with obvious white or silver abdominal stretch marks. Participants were randomly allocated to group A (blank group), group B (topical product group), group C (product combined with nanofractional radiofrequency), and group D (vehicle combined with nanofractional radiofrequency). The stretch mark width, skin elasticity, skin color, skin thickness, and collagen density were noninvasively measured. Two trained assessors evaluated the severity, color, outline, and relaxation of the striae.

RESULTS

Group C showed the best treatment efficacy, with no adverse effects observed during the study period.

CONCLUSION

Our findings indicate that stretch mark treatment using topical formulations containing beta-glucan, combined with nanofractional radiofrequency plus magnetic nanofractional radiofrequency, is tolerable and effective.

TRIAL REGISTRATION

ChiCTR2200056725.

Topical vanadate improves tensile strength and alters collagen organisation of excisional wounds in a mouse model

Wound dehiscence, oftentimes a result of the poor tensile strength of early healing wounds, is a significant threat to the post-operative patient, potentially causing life-threatening complications. Vanadate, a protein tyrosine phosphatase inhibitor, has been shown to alter the organisation of deposited collagen in healing wounds and significantly improve the tensile strength of incisional wounds in rats. In this study, we sought to explore the effects of locally administered vanadate on tensile strength and collagen organisation in both the early and remodelling phases of excisional wound healing in a murine model. Wild-type mice underwent stented excisional wounding on their dorsal skin and were divided equally into three treatment conditions: vanadate injection, saline injection control and an untreated control. Tensile strength testing, in vivo suction Cutometer analysis, gross wound measurements and histologic analysis were performed during healing, immediately upon wound closure, and after 4 weeks of remodelling. We found that vanadate treatment significantly increased the tensile strength of wounds and their stiffness relative to control wounds, both immediately upon healing and into the remodelling phase. Histologic analysis revealed that these biomechanical changes were likely the result of increased collagen deposition and an altered collagen organisation composed of thicker and distinctly organised collagen bundles. Given the risk that dehiscence poses to all operative patients, vanadate presents an interesting therapeutic avenue to improve the strength of post-operative wounds and unstable chronic wounds to reduce the risk of dehiscence.

Bayesian Inference With Gaussian Process Surrogates to Characterize Anisotropic Mechanical Properties of Skin From Suction Tests

One of the intrinsic features of skin and other biological tissues is the high variation in the mechanical properties across individuals and different demographics. Mechanical characterization of skin is still a challenge because the need for subject-specific in vivo parameters prevents us from utilizing traditional methods, e.g., uniaxial tensile test. Suction devices have been suggested as the best candidate to acquire mechanical properties of skin noninvasively, but capturing anisotropic properties using a circular probe opening-which is the conventional suction device-is not possible. On the other hand, noncircular probe openings can drive different deformations with respect to fiber orientation and therefore could be used to characterize the anisotropic mechanics of skin noninvasively. We propose the use of elliptical probe openings and a methodology to solve the inverse problem of finding mechanical properties from suction measurements. The proposed probe is tested virtually by solving the forward problem of skin deformation by a finite element (FE) model. The forward problem is a function of the material parameters. In order to solve the inverse problem of determining skin properties from suction data, we use a Bayesian framework. The FE model is an expensive forward function, and is thus substituted with a Gaussian process metamodel to enable the Bayesian inference problem.