Skin Stiffness Research Articles

Using Machine Learning to Link Genotype Data with Phenotypic Traits in Complex Genetic Disorders

Genetic disorders are among the most devastating diseases that affect humans. Yet, several genetic disorders remain incomprehensible to scientists and doctors. Correlating genotype data with phenotypic manifestations has the potential to help scientists better understand complex genetic disorders, such as Fibrodysplasia Ossificans Progressiva (FOP), Wilson’s disease, and Stiff Skin Syndrome. However, if such processes were done manually by humans, they might lead to severe errors or misconceptions and, quite simply, be a waste of time. Computer algorithms and machine learning techniques can be efficiently utilized to analyze genotype data along with phenotypic manifestations, providing scientists with the necessary data to reach accurate conclusions on misunderstood diseases.

Cardiovascular risks and endothelial dysfunction in reproductive-age women with endometriosis

Endometriosis is a prevalent gynecological condition, affecting around 10% of reproductive-age women. Inflammatory processes associated with endometriosis may contribute to endothelial dysfunction. Increased skin accumulation of advanced glycation end-products (AGEs), reflecting arterial stiffness, potentially links endometriosis with elevated risk of cardiovascular events. We hypothesized that patients with endometriosis have impaired endothelial function as well as increased arterial stiffness and AGE skin accumulation, compared to healthy controls. We compared endothelial function, arterial stiffness, and levels of AGEs in patients suffering from endometriosis and in healthy controls. The study included 45 women aged 20 to 40: 21 patients with endometriosis and 24 healthy controls, matched in terms of age, BMI, and blood pressure values. Endo-PAT 2000 device was used for non-invasive assessment of (i) endothelial function, expressed as Reactive Hyperemia Index (RHI), and (ii) arterial stiffness, expressed as Augmentation Index (AI) and Augmentation Index at 75 heart beats/min (AI@75). Endothelial dysfunction was defined as an RHI value ≤ 1.67. AGE Reader device was used for non-invasive evaluation of skin AGE level accumulation. Patients with endometriosis had lower mean RHI values (1.69 ± 0.54 vs. 2.02 ± 0.48, p = 0.037) and a higher prevalence of endothelial dysfunction, (52.4% vs. 20.8%, p = 0.027) compared to healthy controls. Skin AGE level was higher in patients with endometriosis, compared to controls (2.00 ± 0.57 vs. 1.70 ± 0.24, p = 0.013). There were no significant differences in AI and AI@75 between the two groups. Patients with endometriosis have impaired endothelial function and higher AGE skin accumulation, which are well-established preclinical manifestations of increased cardiovascular risk. There is a great need for comprehensive cardiovascular risk assessments in women with endometriosis to prevent the development of potential atherosclerotic-based complications.

The asymptotic-numerical method for the post-buckling response of curvilinearly stiffened panels

Abstract In the present work, the asymptotic-numerical method is applied in conjunction with the Ritz method as a powerful mean for analysing the post-buckling response of panels with variable stiffness skin and curvilinear stringers. Main advantage of the proposed approach is the reduced computational time. The Ritz method guarantees an excellent ratio between accuracy and required degrees of freedom; the asymptotic-numerical method requires just one matrix inversion throughout the solution process. Moreover, the complete analytical representation of the non-linear equilibrium path is obtained, as opposed to the point-by-point representation of predictor-corrector algorithms. Several test cases are presented and compared with standard Newton-Raphson computations and commercial finite element simulations. The results show noticeable saving of computational time. For the test cases investigated, the asymptotic-numerical method requires about one third of the time required by a standard Newton-Raphson routine. These results demonstrate that the combination between Ritz and the asymptotic-numerical method is an excellent strategy for investigating the post-buckling response of innovative curvilinearly stiffened panels.

The diagnostic value and clinical relevance of high frequency ultrasound and shear wave elastography in systemic sclerosis: an observational monocentric study.

To unravel the features of skin involvement in patients with systemic sclerosis (SSc) by high frequency ultrasound (HFU) and shear wave elastography (SWE). To assess the ultrasound capabilities to distinguish SSc patients from healthy controls (HCs). We recruited a cohort of SSc patients in this cross-sectional study. HFU and SWE were used to quantify skin thickness and skin stiffness. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic capabilities of ultrasound in SSc. The correlation analysis was used to evaluate the clinical relevance of ultrasound measurements in SSc. 20 consecutive SSc patients and 20 age-, gender- and body mass index-matched HCs were included. The skin thickness and stiffness were significantly greater in SSc patients compared with HCs. Patients with high disease activity had higher skin thickness and stiffness compared with patients with low disease activity. The area under the ROC curve (AUC) of the dorsum of middle fingers assessed by HFU was 0.847 (95% CI, 0.761-0.933). The AUC of the forearms and dorsum of hands assessed by SWE were 0.909 (95% CI, 0.829-0.989) and 0.879 (95% CI, 0.807-0.951). Further, the combined HFU and SWE tests displayed the best diagnostic performance with an AUC of 0.980 (95% CI, 0.939-1.000). A significant positive correlation between the ultrasound measurements and the modified Rodnan skin score (mRSS) was observed. The application of ultrasound can assist with disease diagnosis, it is necessary to develop a standard operating protocol to help with future implementation of ultrasound in SSc.

Electromechanical coupling optimization for a sandwich beam activation using piezoceramics

Sandwich beams composed of two stiff carbon fiber skins and a viscoelastic core are often used to passively dissipate energy through the activation of shearing in a specific frequency range. Semi-active or active energy dissipation can be made possible on those structures adding piezoelectric patches, coupling mechanical vibration energy and electrical energy. J.L. Guyader et al. [jsv, 1978] theorized a frequency dependent equivalent dynamic model of a sandwich structure, recently extended to the homogenization of anisotropic multi-layers by F.Marchetti et al. [jsv, 2020]. This frequency-dependent stiffness of the beam has to be taken into account in the piezoceramic thickness definition in order to optimize the global electromechanical coupling coefficient. An analytical model is derived from the works of F.Marchetti et al. and adapted to predict the first vibration mode of a finite cantilever beam instrumented with a piezoelectric patch. The electromechanical coupling evolution is then calculated with the proper boundary conditions and for different PZT ceramic thicknesses. This model is furtherly used to define the best transducer configuration for a given sandwich structure beam.

The effect of female breast surface area on skin stiffness and tactile sensitivity at rest and following exercise in the heat.

Female development includes significant morphological changes across the breast. Yet, whether differences in breast surface area (BrSA) modify breast skin stiffness and tactile sensitivity at rest and after exercise in the heat remain unclear. We investigated the relationship between BrSA and skin stiffness and tactile sensitivity in 20 young to middle-aged women (27±8years of age) of varying breast sizes (BrSA range: 147-502cm2) at rest and after a submaximal run in a warm climatic chamber (32 ± 53%±1.7% relative humidity). Skin stiffness above and below the nipple and tactile sensitivity from the nipple down were measured. Associations between BrSA and both skin stiffness and tactile sensitivity at rest were determined via correlation analyses. Effects of exercise and test site were assessed by a two-way ANOVA. Skin stiffness was positively correlated with BrSA 3cm above the areola edge (r=0.61, P=0.005) and at the superior areola border (r=0.54, P=0.016), but not below the nipple (P>0.05). The area 3cm below the areola was also significantly stiffer than all other test sites (P<0.043). Tactile sensitivity did not vary with BrSA (P>0.09), but it varied across the breast (i.e., the area 3cm below the areola was more sensitive than the inferior areola edge; P=0.018). Skin stiffness and tactile sensitivity across the breast decreased after exercise by ∼37% (P<0.001) and ∼45% (P=0.008), respectively. These findings expand our fundamental understanding of the mechanosensory properties of the female breast, and they could help to inform sportswear innovation to better meet the support needs of women of different breast sizes at rest and following exercise.

Cross-sectional study using the University of California, Los Angeles, Scleroderma Clinical Trials Consortium Gastrointestinal Tract Instrument 2.0 (UCLA SCTC GIT 2.0) for gastrointestinal disorders of systemic sclerosis.

This study aimed to identify severe gastrointestinal ailments in patients with systemic sclerosis (SSc), investigate the role of antibodies in gastrointestinal disorders, and explore the relationship between limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc) in terms of gastrointestinal involvement and its association with skin stiffness. We used the University of California, Los Angeles, Scleroderma Clinical Trials Consortium Gastrointestinal Tract Instrument 2.0 (UCLA SCTC GIT 2.0) questionnaire to assess gastrointestinal disturbances in 100 patients with SSc. Gastrointestinal impairment was categorized into three levels: absence of or minor symptoms, moderate symptoms, and severe symptoms, as indicated by the total gastrointestinal tract (GIT) score. Comparing 27 patients with dcSSc and 73 patients with lcSSc, severe gastrointestinal disturbances were found in 7.4% of patients with dcSSc and 4.1% of patients with lcSSc. A total of 18.0% of anticentromere antibody (ACA)-positive patients exhibited moderate to severe symptoms, while 9.1% of antitopoisomerase 1 antibody-positive patients displayed similar symptoms. The average disease duration in patients with severe symptoms was 15.0 years, in those with moderate symptoms was 10.3 years, and in those who were symptom-free or mildly affected was 8.5 years. Among 16 patients with moderate to severe gastrointestinal disorders, a positive correlation was observed between the modified Rodnan skin thickness score (mRSS) and total GIT score. In addition, a positive correlation was identified between fecal incontinence and mRSS, with weaker correlations for reflux and bloating symptoms. Patients with gastrointestinal disorders showed a tendency to worsen over time, particularly in ACA-positive patients with dcSSc. Furthermore, a correlation was observed between mRSS and fecal incontinence, reflux, and abdominal bloating in patients with moderate to severe gastrointestinal disturbances.

Dual optical elastography detects -induced alterations in the biomechanical properties of skin scaffolds.

The skin's mechanical properties are tightly regulated. Various pathologies can affect skin stiffness, and understanding these changes is a focus in tissue engineering. Ex vivo skin scaffolds are a robust platform for evaluating the effects of various genetic and molecular interactions on the skin. Transforming growth factor-beta ( ) is a critical signaling molecule in the skin that can regulate the amount of collagen and elastin in the skin and, consequently, its mechanical properties. This study investigates the biomechanical properties of bio-engineered skin scaffolds, focusing on the influence of , a signaling molecule with diverse cellular functions. The receptor I inhibitor, galunisertib, was employed to assess the mechanical changes resulting from dysregulation of . Skin scaffold samples, grouped into three categories (control, -treated, and + galunisertib-treated), were prepared in two distinct culture media-one with aprotinin (AP) and another without. Two optical elastography techniques, namely wave-based optical coherence elastography (OCE) and Brillouin microscopy, were utilized to quantify the biomechanical properties of the tissues. Results showed significantly higher wave speed (with AP, ; without AP, ) and Brillouin frequency shift (with AP, ; without AP, ) in -treated group compared with the control group. The difference in wave speed between the control and + galunisertib with ( ) and without AP ( ) was not significant. Moreover, the + galunisertib-treated group exhibited lower wave speed without and with AP and reduced Brillouin frequency shift than the -treated group without AP, further strengthening the potential role of in regulating the mechanical properties of the samples. These findings offer valuable insights into -induced biomechanical alterations in bio-engineered skin scaffolds, highlighting the potential of OCE and Brillouin microscopy in the development of targeted therapies in conditions involving abnormal tissue remodeling and fibrosis.

Tissue expansion mitigates radiation-induced skin fibrosis in a porcine model

Tissue expansion (TE) is the primary method for breast reconstruction after mastectomy. In many cases, mastectomy patients undergo radiation treatment (XR). Radiation is known to induce skin fibrosis and is one of the main causes for complications during post-mastectomy breast reconstruction. TE, on the other hand, induces a pro-regenerative response that culminates in growth of new skin. However, the combined effect of XR and TE on skin mechanics is unknown. Here we used the porcine model of TE to study the effect of radiation on skin fibrosis through biaxial testing, histological analysis, and kinematic analysis of skin deformation over time. We found that XR leads to stiffening of skin compared to control based on a shift in the transition stretch (transition between a low stiffness and an exponential stress-strain region characteristic of collagenous tissue) and an increase in the high modulus (modulus computed with stress-stretch data past the transition point). The change in transition stretch can be explained by thicker, more aligned collagen fiber bundles measured in histology images. Skin subjected to both XR+TE showed similar microstructure to controls as well as similar biaxial response, suggesting that physiological remodeling of collagen induced by TE partially counteracts pro-fibrotic XR effects. Skin growth was indirectly assessed with a kinematic approach that quantified increase in permanent area changes without reduction in thickness, suggesting production of new tissue driven by TE even in the presence of radiation treatment. Future work will focus on the detailed biological mechanisms by which TE counteracts radiation induced fibrosis. Statement of significanceBreast cancer is the most prevalent in women and its treatment often results in total breast removal (mastectomy), followed by reconstruction using tissue expanders. Radiation, which is used in about a third of breast reconstruction cases, can lead to significant complications. The timing of radiation treatment remains controversial. Radiation is known to cause immediate skin damage and long-term fibrosis. Tissue expansion leads to a pro-regenerative response involving collagen remodeling. Here we show that tissue expansion immediately prior to radiation can reduce the level of radiation-induced fibrosis. Thus, we anticipate that this new evidence will open up new avenues of investigation into how the collagen remodeling and pro-regenerative effects of tissue expansion can be leverage to prevent radiation-induced fibrosis.

Topographical changes in extracellular matrix during skin fibrosis and recovery can be evaluated using automated image analysis algorithms.

Skin fibrosis is characterized by fibroblast activation and intradermal fat loss, resulting in excess deposition and remodeling of dermal extracellular matrix (ECM). The topography of the dominant ECM proteins, such as collagens, can indicate skin stiffness and remains understudied in evaluating fibrotic skin. Here, we adapted two different unbiased image analysis algorithms to define collagen topography and alignment in a genetically inducible and reversible Wnt activation fibrosis model. We demonstrated that Wnt-activated fibrotic skin has altered collagen fiber characteristics and a loss of collagen alignment, which were restored in the reversible model. This study highlights how unbiased algorithms can be used to analyze ECM topography, providing novel avenues to evaluate fibrotic skin onset, recovery, and treatment.

New clinical classification of stiff skin syndrome.

Stiff skin syndrome (SSS) is a rare disease characterized by thickened, indurated skin and limited joint movement. Multiple diverse phenotypes have been reported, and the correlation of severity with the clinical heterogeneity and histopathological findings of SSS needs to be refined. To define subtypes based on clinical features and predict the prognosis of a new SSS classification. Eighty-three patients with SSS were retrospectively reviewed for clinicopathological manifestations and routine laboratory workup, including 59 cases obtained from a PubMed search between 1971 and 2022 and 24 cases diagnosed in our department between 2003 and 2022. Among the 83 patients, 27.7, 41, and 31.3% had classic widespread, generalized segmental, and localized SSS, respectively. Joint immobility was present in 100, 71, and 20% of classic, generalized, and localized cases, respectively. Histopathologic findings were common among the 3 groups, and based on that, we further found a difference in the distribution of proliferative collagen. 54.5% of classic and 50% of generalized cases occurred throughout the dermis or the subcutis, whereas 76% of localized cases were mainly involved in the reticular dermis or subcutis. In patients with incipient localized SSS, 42% (21/50) developed generalized SSS, and only 6% (3/50) progressed to classic SSS, whereas more than half of the incipient generalized SSS cases (60.6%, 20/33) developed classic SSS. This retrospective study was limited to previously published cases with limited data. We propose a distinct clinical classification characterized by lesion distribution, including classic widespread, generalized segmental, and localized SSS, associated with disease severity and prognosis.

Hyaline fibromatosis syndrome: a rare, yet recognizable syndrome.

Hyaline fibromatosis syndrome is a rare autosomal recessive disorder caused by ANTXR2 pathogenic variants. The disorder is characterized by the deposition of amorphous hyaline material in connective tissues. The hallmarks of the disease are joint contractures, generalized skin stiffness, hyperpigmented papules over extensor surfaces of joints, fleshy perianal masses, severe diarrhea, and gingival hypertrophy. The severity of the disease varies and prognosis is poor. No specific treatment is yet available. Most patients with the severe form of the condition pass away before the second year of age. In this study, we describe the clinical and molecular findings of a cohort of seven hyaline fibromatosis syndrome patients who were diagnosed and followed up at a single tertiary reference center in Turkey. Genomic DNA was extracted by standard salting out method from peripheric blood samples of three patients. In one patient DNA extraction was performed on pathology slides since peripheric blood DNA was not available. All coding exons of the ANTXR2 were amplified and sequenced on ABI Prism 3500 Genetic Analyser. Sanger sequencing was performed in 3 patients and homozygous c.945T>G p.(Cys315Trp), c.1073dup p.(Ala359CysfsTer13), and c.1074del p.(Ala359HisfsTer50) variants were identified in ANTXR2. All patients passed away before the age of five years. HFS is a rare, progressive disorder with a broad phenotypic spectrum. HFS can be recognized easily with distinctive clinical features. Nevertheless, it has poor prognosis with increased mortality due to severe clinical decompensation.

Layer jamming skin‐based bionic webbed foot soft gripper with variable stiffness and envelopment

Inspired by webbed feet, a bionic webbed foot soft gripper with variable stiffness was designed by integrating a pneumatic networks actuator with layer jamming skin. Layer jamming skin as the key component of bionic webbed foot soft gripper, its design and fabrication process were described. An experimental platform combining stretch/bend control was established to analyze the impact of activated negative pressure, different materials and shapes jamming units, and the number of jamming layers on the stiffness of the layer jamming skin. The layer jamming skin conforms to the characteristics of variable stiffness by evaluating the experimental and numerical results of the layer jamming skin under external loading. The curling and adaptability test demonstrated the layer jamming skin's adaptability and flexibility to various shapes and sizes of caught objects. The variable stiffness, adaptability, and gripping force of the bionic webbed foot soft gripper during object grasping were assessed through gripping experiments. This work presents an enveloping gripper with variable stiffness, high adaptability, and strong grasping force.

A Gaussian process approach for rapid evaluation of skin tension

Skin tension plays a pivotal role in clinical settings, it affects scarring, wound healing and skin necrosis. Despite its importance, there is no widely accepted method for assessing in vivo skin tension or its natural pre-stretch. This study aims to utilise modern machine learning (ML) methods to develop a model that uses non-invasive measurements of surface wave speed to predict clinically useful skin properties such as stress and natural pre-stretch. A large dataset consisting of simulated wave propagation experiments was created using a simplified two-dimensional finite element (FE) model. Using this dataset, a sensitivity analysis was performed, highlighting the effect of the material parameters and material model on the Rayleigh and supersonic shear wave speeds. Then, a Gaussian process regression model was trained to solve the ill-posed inverse problem of predicting stress and pre-stretch of skin using measurements of surface wave speed. This model had good predictive performance (R2 = 0.9570) and it was possible to interpolate simplified parametric equations to calculate the stress and pre-stretch. To demonstrate that wave speed measurements could be obtained cheaply and easily, a simple experiment was devised to obtain wave speed measurements from synthetic skin at different values of pre-stretch. These experimental wave speeds agree well with the FE simulations, and a model trained solely on the FE data provided accurate predictions of synthetic skin stiffness. Both the simulated and experimental results provide further evidence that elastic wave measurements coupled with ML models are a viable non-invasive method to determine in vivo skin tension. Statement of significanceTo prevent unfavourable patient outcomes from reconstructive surgery, it is necessary to determine relevant subject-specific skin properties. For example, during a skin graft, it is necessary to estimate the pre-stretch of the skin to account for shrinkage upon excision. Existing methods are invasive or rely on the experience of the clinician. Our work aims to present an innovative framework to non-invasively determine in vivo material properties using the speed of a surface wave travelling through the skin. Our findings have implications for the planning of surgical procedures and provides further motivation for the use of elastic wave measurements to determine in vivo material properties.

Numerical parametric study of embedded geosynthetic-reinforced soil abutment

Three-dimensional numerical analysis was conducted to investigate the performance of embedded geosynthetic-reinforced soil abutments. The numerical model was validated using field-monitoring data. A parametric study was conducted to investigate the key factors affecting the performance of the embedded abutment under the working conditions, including the pile offset distance, pile diameter, pile spacing, and bridge load. The piles exhibited a retaining rather than a pushing effect in these cases due to the relatively high stiffness and negative skin friction of the piles, thus reducing the loads exerted on the facing wall. The lateral displacement of the facing wall significantly increased as the pile offset distance decreased mainly due to the reduced anchor length of the reinforcement and enhanced retaining effect of the piles. As the pile diameter increases, the deflection of the facing wall is constrained by factors such as increased bearing width, limited displacement, and enhanced retention effect of thepiles. This is an efficient way to increase the pile density near the abutment centerline to control thedeformation of the facing wall. An increase in the vertical bridge load resulted in a decrease in negative skin friction, leading to increased foundation settlement and lateral displacement of the facing wall.

Exploring Anti-Fibrotic Effects of Adipose-Derived Stem Cells: Transcriptome Analysis upon Fibrotic, Inflammatory, and Hypoxic Conditioning.

Autologous fat transfers show promise in treating fibrotic skin diseases, reversing scarring and stiffness, and improving quality of life. Adipose-derived stem cells (ADSCs) within these grafts are believed to be crucial for this effect, particularly their secreted factors, though the specific mechanisms remain unclear. This study investigates transcriptomic changes in ADSCs after in vitro fibrotic, inflammatory, and hypoxic conditioning. High-throughput gene expression assays were conducted on ADSCs exposed to IL1-β, TGF-β1, and hypoxia and in media with fetal bovine serum (FBS). Flow cytometry characterized the ADSCs. RNA-Seq analysis revealed distinct gene expression patterns between the conditions. FBS upregulated pathways were related to the cell cycle, replication, wound healing, and ossification. IL1-β induced immunomodulatory pathways, including granulocyte chemotaxis and cytokine production. TGF-β1 treatment upregulated wound healing and muscle tissue development pathways. Hypoxia led to the downregulation of mitochondria and cellular activity.

In the face and neck, keloid scar distribution is related to skin thickness and stiffness changes associated with movement.

Keloid scars tend to occur in high-tension sites due to mechanical stimuli that are involved in their development. To date, a detailed analysis of keloid distribution focused specifically on facial and neck areas has not been reported, and limited literature exists as to the related mechanical factors. To rectify this deficiency of knowledge, we first quantified the facial and neck keloid distribution observed clinically in 113 patients. Subsequently, we performed a rigorous investigation into the mechanical factors and their associated changes at these anatomic sites in healthy volunteers without a history of pathologic scarring. The association between keloid-predilection sites and sebaceous gland-dense and acne-prone sites was also examined. To assess skin stretch, thickness and stiffness, VECTRA, ultrasound and indentometer were utilised. Baseline skin stiffness and thickness were measured, as well as the magnitude of change in these values associated with facial expression and postural changes. Within the face and neck, keloids were most common near the mandibular angle (41.3%) and lateral submental (20.0%) regions. These areas of increased keloid incidence were not associated with areas more dense in sebaceous glands, nor linked consistently with acne-susceptible regions. Binomial logistic regression revealed that changes in skin stiffness and thickness related to postural changes significantly predicted keloid distribution. Skin stiffness and thickness changes related to prolonged mechanical forces (postural changes) are most pronounced at sites of high keloid predilection. This finding further elucidates the means by which skin stretch and tension are related to keloid development. As a more detailed analysis of mechanical forces on facial and neck skin, this study evaluates the nuances of multiple skin-mechanical properties, and their changes in a three-dimensional framework. Such factors may be critical to better understanding keloid progression and development in the face and neck.

High Pressure 3 × 30 Minute Compression Methods for Advanced Lower Limb Lymphedema Patients.

Introduction: In advanced lymphedema of lower limbs, stage III bandaging under the routinely applied pressure of 40-60 mmHg remains largely ineffective. This is caused by skin and subcutaneous tissue stiffness due to fibrosis. Edema fluid accumulates deep in the subcutaneous tissue. Evacuating this fluid requires a high external compression force to overcome the resistance of fibrous tissue. We aimed to investigate the effectiveness of the compression method, with high pressure lasting for 3 days. Methods and Results: Twenty-one patients with lower limb lymphedema, stage III, of the postinflammatory type were included. Patients with acute inflammatory symptoms, venous thrombosis, profuse varicose veins, diabetes, and cardiac insufficiency with edema were excluded. A 10-cm-wide rubber bandage was applied to the foot and calf. The interface pressure measured using PicoPress ranged from 58 to 120 mmHg. Skin and deep tissue tonometry, skin water concentration, leg circumference, and drop of interface pressure were measured. Ultrasound examination was done before and after each compression session. The calf circumference decreased by 15.9 ± 5.4%, deep tissue stiffness by 58.9 ± 18.9%, skin stiffness by 69.6 ± 13.5%, and skin water concentration by 43.8 ± 11.5%. Interface pressure dropped to 66.3 mmHg (28-110 mmHg); ultrasonography images showed less fluid in the tissue. Conclusions: High-pressure 30-minute leg compression can remove excess edema fluid within 3 days and enable adjustment of nonstretch compression stockings. This method is more effective in advanced lymphedema at the beginning of therapy than the standard 30-50-mmHg bandaging as it provides an immediate effect.

Effects of a leave-on product on the strength of the dermoepidermal junction: An exploratory, intraindividual, randomized controlled trial in older adults with dry skin.

Skin aging is associated with dry skin and a decrease of the strength of the dermoepidermal adhesion, which increases the risk for lacerations (skin tears). Application of leave-on products improves dry skin and seems to reduce skin tear incidence. The aim of this study was to measure the effects of a humectant containing leave-on product on the strength of the dermoepidermal junction in older adult participants with dry skin. A randomized controlled trial using a split body design was conducted. One forearm was randomly selected and treated with a lipophilic leave-on product containing 5% urea for 8 weeks. The other forearm was the control. The parameters stratum corneum hydration (SCH), transepidermal water loss, pH, roughness, epidermal thickness and skin stiffness were measured at the baseline, Weeks 4 and 8. At Week 8, suction blisters were created and time to blistering was measured. Blister roofs and interstitial fluid were analyzed for Interleukin-1α, 6 and 8. Twelve participants were included. After 8 weeks treatment, SCH was higher (median difference 11.6 AU), and the overall dry skin score (median difference -1) and median roughness (Rz difference -12.2 µm) were lower compared to the control arms. The median group difference for Interleukin-1α was -452 fg/µg total protein (TP) in the blister roofs and -2.2 fg/µg TP in the blister fluids. The median time to blister formation was 7.7 min higher compared to the control arms. The regular application of humectant containing leave-on products improves dry skin and seems to lower inflammation and contribute to the strengthening of the dermoepidermal adhesion. This partly explains how the use of topical leave-on products helps to prevent skin tears.

Surfacic characterization of soft tissues biomechanical properties using impact-based methods: A comparative study

Various methods have been developed to assess the skin stiffness in order to assist the clinician for therapeutic monitoring or these diagnoses. The objective of this work was to compare the performances of a new acoustical characterization method based on impact analysis with those of two existing approaches, namely (i) a suction device, the Cutometer®, and (ii) a digital palpation tool, the MyotonPro®. This new impact analysis method is based on the analysis of the temporal variation of the force obtained during the impact of an instrumented hammer on a cylindrical punch placed in contact with a soft tissue mimicking phantom (Technogel®). The performances of the three aforementioned techniques (sensitivity and resolution) were assessed using homogeneous or bilayer structures with various thickness and rigidity, formed by different soft tissues mimicking gel pads. The impact analysis based method (IBAM) was two times better than the other two approaches in terms of reproducibility and sensitivity. The axial resolution of the IBAM was around 20 times better compared to the two other methods. The results open the way for the development of a cheap, non-invasive and objective method that could be used in the future in the cosmetic industry and in dermatology. This project has received funding from the projects OrthAncil (ANR-21-CE19-0035-03) and from the project OrthoMat (ANR-21-CE17-0004).