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Ma S, Zhang Z, Li GY, Cao Y. Guided wave elastography of human skins with a layered model incorporating the effect of muscle state. J Biomech 2024; 174:112279. [PMID: 39146898 DOI: 10.1016/j.jbiomech.2024.112279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 07/30/2024] [Accepted: 08/09/2024] [Indexed: 08/17/2024]
Abstract
In vivo mechanical characterization of skin finds broad applications in understanding skin aging, diagnosis of some skin diseases and assessing the effectiveness of diverse skin care strategies. Skin has a layered structure consisting of the epidermis, dermis and subcutaneous layers. Although much effort has been made towards mechanical characterization of skin, it remains a challenging issue to measure the mechanical properties of an individual layer in vivo. To address this issue, we here report a guided wave elastography method for layered human skin which incorporates the effect of muscle states. Both finite element simulations and phantom experiments have been performed to validate the method. For skin-mimicking phantoms with different fat layer thicknesses, the errors in the identified shear modulus of the skin layers are no more than 11 %. In vivo experiments have been carried out on 6 healthy subjects to demonstrate the potential use of the method in clinics. A statistical analysis indicates the muscle contraction contributes to the stiffening of the skin (p < 0.001). Finally, a phase diagram has been constructed to reveal the extent to which muscle sates (including both passive and active states) affect the measurement of elastic modulus of a skin layer, which may guide the application of the method in practice.
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Affiliation(s)
- Shiyu Ma
- Institute of Biomechanics and Medical Engineering, AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, PR China
| | - Zhaoyi Zhang
- Institute of Biomechanics and Medical Engineering, AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, PR China
| | - Guo-Yang Li
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, PR China
| | - Yanping Cao
- Institute of Biomechanics and Medical Engineering, AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, PR China.
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Oliveira RN, Meleiro LADC, Quilty B, McGuinness GB. Release of natural extracts from PVA and PVA-CMC hydrogel wound dressings: a power law swelling/delivery. Front Bioeng Biotechnol 2024; 12:1406336. [PMID: 39165402 PMCID: PMC11333833 DOI: 10.3389/fbioe.2024.1406336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Accepted: 07/05/2024] [Indexed: 08/22/2024] Open
Abstract
Introduction PVA hydrogels present many characteristics of the ideal dressing, although without antimicrobial properties. The present work aims to study the physical, mechanical and release characteristics of hydrogel wound dressings loaded with either of two natural herbal products, sage extract and dragon's blood. Methods Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and tensile mechanical testing were used to investigate the structure and properties of the gels. Swelling and degradation tests were conducted according to ISO 10993-9. Release characteristics were studied using UV Spectrophotometry. Results PVA matrices incorporating sage extract or dragon's blood (DB) present hydrogen bonding between these components. PVA-CMC hydrogels containing sage present similar spectra to PVA-CMC alone, probably indicating low miscibility or interaction between the matrix and sage. The opposite is found for DB, which exhibits more pronounced interference with crystallinity than sage. DB and NaCMC negatively affect Young's modulus and failure strength. All samples appear to reach equilibrium swelling degree (ESD) in 24 h. The addition of DB and sage to PVA increases the gels' swelling capacity, indicating that the substances likely separate PVA chains. The inclusion of CMC contributes to high media uptake. The kinetics profile of media uptake for 4 days is described by a power-law model, which is correlated to the drug delivery mechanism. Discussion A PVA-CMC gel incorporating 15% DB, the highest amount tested, shows the most favorable characteristics for flavonoid delivery, as well as flexibility and swelling capacity.
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Affiliation(s)
- Renata Nunes Oliveira
- Chemical Engineering Department, Institute of Technology, Federal Rural University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luiz Augusto da Cruz Meleiro
- Chemical Engineering Department, Institute of Technology, Federal Rural University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Brid Quilty
- School of Biotechnology, Dublin City University, Dublin, Ireland
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Alberini R, Spagnoli A, Sadeghinia MJ, Skallerud B, Terzano M, Holzapfel GA. Second harmonic generation microscopy, biaxial mechanical tests and fiber dispersion models in human skin biomechanics. Acta Biomater 2024:S1742-7061(24)00398-2. [PMID: 39048027 DOI: 10.1016/j.actbio.2024.07.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 07/13/2024] [Accepted: 07/16/2024] [Indexed: 07/27/2024]
Abstract
Advanced numerical simulations of the mechanical behavior of human skin require thorough calibration of the material's constitutive models based on experimental ex vivo mechanical tests along with images of tissue microstructure for a variety of biomedical applications. In this work, a total of 14 human healthy skin samples and 4 additional scarred skin samples were experimentally analyzed to gain deep insights into the biomechanics of human skin. In particular, second harmonic generation (SHG) microscopy was used to extract detailed images of the distribution of collagen fibers, which were subsequently processed using a three-dimensional Fourier transform-based method recently proposed by the authors to quantify the distribution of fiber orientations. Mechanical tests under both biaxial and uniaxial loading were performed to calibrate the relevant mechanical parameters of two widely used constitutive models of soft fiber-reinforced biological tissues that account for non-symmetrical fiber dispersion. The calibration of the models allowed us to identify correlations between the mechanical parameters of the constitutive models considered. STATEMENT OF SIGNIFICANCE: Constitutive models for soft collagenous tissues can accurately reproduce the complex nonlinear and anisotropic mechanical behavior of skin. However, a comprehensive analysis of both microstructural and mechanical parameters is still missing for human skin. In this study, these parameters are determined by combining biaxial mechanical tests and SHG stacks of collagen fibers on ex vivo healthy human skin samples. The constitutive parameters are provided for two widely used hyperelastic models and enable accurate characterization of skin mechanical behavior for advanced numerical simulations.
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Affiliation(s)
- Riccardo Alberini
- Department of Engineering and Architecture, University of Parma, Parma, Italy
| | - Andrea Spagnoli
- Department of Engineering and Architecture, University of Parma, Parma, Italy.
| | - Mohammad Javad Sadeghinia
- Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Bjorn Skallerud
- Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Michele Terzano
- Institute of Biomechanics, Graz University of Technology, Graz, Austria
| | - Gerhard A Holzapfel
- Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Institute of Biomechanics, Graz University of Technology, Graz, Austria
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Cho H, Dohi T, Wakai H, Quong WL, Linh NDT, Usami S, Ogawa R. In the face and neck, keloid scar distribution is related to skin thickness and stiffness changes associated with movement. Wound Repair Regen 2024; 32:419-428. [PMID: 38602106 DOI: 10.1111/wrr.13180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 02/25/2024] [Accepted: 04/01/2024] [Indexed: 04/12/2024]
Abstract
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.
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Affiliation(s)
- Hoyu Cho
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
| | - Teruyuki Dohi
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
| | - Hanae Wakai
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
| | - Whitney Laurel Quong
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
- Department of Plastic, Reconstructive, and Aesthetic Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Nguyen Doan Tien Linh
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
| | - Satoshi Usami
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
- Graduate School of Education, The University of Tokyo, Tokyo, Japan
| | - Rei Ogawa
- Department of Plastic, Reconstructive and Regenerative Surgery, Nippon Medical School, Tokyo, Japan
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Li F, Zhi J, Zhao R, Sun Y, Wen H, Cai H, Chen W, Jiang X, Bai R. Discovery of matrix metalloproteinase inhibitors as anti-skin photoaging agents. Eur J Med Chem 2024; 267:116152. [PMID: 38278079 DOI: 10.1016/j.ejmech.2024.116152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 01/11/2024] [Indexed: 01/28/2024]
Abstract
Photodamage is the result of prolonged exposure of the skin to sunlight. This exposure causes an overexpression of matrix metalloproteinases (MMPs), leading to the abnormal degradation of collagen in the skin tissue and resulting in skin aging and damage. This review presents a detailed overview of MMPs as a potential target for addressing skin aging. Specifically, we elucidated the precise mechanisms by which MMP inhibitors exert their anti-photoaging effects. Furthermore, we comprehensively analyzed the current research progress on MMP inhibitors that demonstrate significant inhibitory activity against MMPs and anti-skin photoaging effects. The review also provides insights into the structure-activity relationships of these inhibitors. Our objective in conducting this review is to provide valuable practical information to researchers engaged in investigations on anti-skin photoaging.
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Affiliation(s)
- Feifan Li
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-tumor Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Jia Zhi
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-tumor Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Rui Zhao
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-tumor Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Yinyan Sun
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-tumor Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Hao Wen
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-tumor Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Hong Cai
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-tumor Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Wenchao Chen
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-tumor Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Xiaoying Jiang
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-tumor Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, PR China
| | - Renren Bai
- School of Pharmacy, Hangzhou Normal University, Hangzhou, 311121, PR China; Key Laboratory of Elemene Class Anti-tumor Chinese Medicines, Engineering Laboratory of Development and Application of Traditional Chinese Medicines, Collaborative Innovation Center of Traditional Chinese Medicines of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121, PR China.
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Borzabadi-Farahani A, Mosahebi A, Zargaran D. A Scoping Review of Hyaluronidase Use in Managing the Complications of Aesthetic Interventions. Aesthetic Plast Surg 2024; 48:1193-1209. [PMID: 36536092 PMCID: PMC10999391 DOI: 10.1007/s00266-022-03207-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 11/19/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND Hyaluronidase is used as an adjunct or main treatment to manage complications associated with cosmetic hyaluronic acid (HA) filler injections such as necrosis, blindness, hypersensitivity, delayed nodules, and poor aesthetic outcomes. OBJECTIVE To systematically map the available evidence and identify the gaps in knowledge on the effectiveness of hyaluronidase use in managing the aesthetic complications associated with HA injections (vascular occlusion, blindness, nodules, delayed hypersensivity, granuloma, poor aesthetic outcome). METHODS PubMed, Medline, Embase and Cochrane databases were used up to May 2022, to look for randomized clinical trials (RCTs), clinical trials, and retrospective case-control studies reporting on the use of hyaluronidase for managing the HA filler injection complications. RESULTS The database search yielded 395 studies; of those 5 RCTs (all carried out in the USA) were selected (53 subjects), indicating the effectiveness of hyaluronidase for removal of un-complicated injected HA nodules (forearm, upper arm, or back skin). The follow-ups ranged from 14 days to 4 years. The amount of HA filler injected into each site varied from 0.2 to 0.4 mL. A dose dependent response was observed for most HA fillers. No major adverse reactions were reported. Overall, for removal of every 0.1 mL of HA filler they injected 1.25-37.5 units of hyaluronidase (single injections). When 3 consecutive weekly hyaluronidase injection was used much lower doses of 0.375-2.25 unit was utilised. There was no evidence in a form of RCTs, clinical trials, and retrospective case-control studies on the removal/reversal of HA injections in the facial skin, or management of over-corrections, inflammatory nodules, or tissue ischemia/necrosis associated with HA filler injection. CONCLUSION Based on studies on the forearm, upper arm and back skin, hyaluronidase can be used for the reversal of uncomplicated HA filler injection nodule. However, further adequately powered studies are warranted to establish the ideal treatment protocol/dose of hyaluronidase for reversal of HA filler injections in the facial region or management of complications associated with aesthetic HA injection. LEVEL OF EVIDENCE III 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 .
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Affiliation(s)
- Ali Borzabadi-Farahani
- Division of Surgery & Interventional Science (Minimally Invasive Aesthetics), University College London (UCL), London, WC1E 6BT, UK.
- Crouch End Orthodontics, 72 Crouch End Hill, London, N8 8AG, England, UK.
| | - Afshin Mosahebi
- Department of Plastic Surgery, Royal Free Hospital, University College London, London, UK
| | - David Zargaran
- Department of Plastic Surgery, Royal Free Hospital, University College London, London, UK
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7
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Romodina MN, Parmar A, Singh K. In vivo measurement of the biomechanical properties of human skin with motion-corrected Brillouin microscopy. BIOMEDICAL OPTICS EXPRESS 2024; 15:1777-1784. [PMID: 38495685 PMCID: PMC10942711 DOI: 10.1364/boe.516032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/18/2024] [Accepted: 01/30/2024] [Indexed: 03/19/2024]
Abstract
Biomechanical testing of human skin in vivo is important to study the aging process and pathological conditions such as skin cancer. Brillouin microscopy allows the all-optical, non-contact visualization of the mechanical properties of cells and tissues over space. Here, we use the combination of Brillouin microscopy and optical coherence tomography for motion-corrected, depth-resolved biomechanical testing of human skin in vivo. We obtained two peaks in the Brillouin spectra for the epidermis, the first at 7 GHz and the second near 9-10 GHz. The experimentally measured Brillouin frequency shift of the dermis is lower compared to the epidermis and is 6.8 GHz, indicating the lower stiffness of the dermis.
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Affiliation(s)
- Maria N. Romodina
- Max Planck Institute for the Science of Light, Staudtstr. 2, 91058 Erlangen, Germany
| | - Asha Parmar
- Max Planck Institute for the Science of Light, Staudtstr. 2, 91058 Erlangen, Germany
- Department of Physics, Friedrich Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Kanwarpal Singh
- Max Planck Institute for the Science of Light, Staudtstr. 2, 91058 Erlangen, Germany
- Department of Physics, Friedrich Alexander University Erlangen-Nürnberg, Erlangen, Germany
- Department of Electrical and Computer Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
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Reuvekamp H, Hekman E, van der Heide E, Matthews D. Strategies in surface engineering for the regulation of microclimates in skin-medical product interactions. Heliyon 2024; 10:e25395. [PMID: 38370189 PMCID: PMC10869805 DOI: 10.1016/j.heliyon.2024.e25395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/17/2023] [Accepted: 01/25/2024] [Indexed: 02/20/2024] Open
Abstract
There is a growing number of personal healthcare devices that are in prolonged contact with the skin. The functionality of these products is linked to the interface formed by the contact between the medical apparatus and the skin. The interface can be characterised by its topology, compliance, and moisture and thermal regulating capabilities. Many devices are, however, described to have suboptimal and occlusive contacts, resulting in physiological unfavourable microclimates at the interface. The resulting poor management of moisture and temperature can impact the functionality and utility of the device and, in severe cases, lead to physical harm to the user. Being able to control the microclimate is therefore expected to limit medical-device related injuries and prevent associated skin complications. Surface engineering can modify and potentially enhance the regulation of the microclimate factors surrounding the interface between a product's surface and the skin. This review provides an overview of potential engineering solutions considering the needs for, and influences on, regulation of temperature and moisture by considering the skin-medical device interface as a system. These findings serve as a platform for the anticipated progress in the role of surface engineering for skin-device microclimate regulation.
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Affiliation(s)
- H. Reuvekamp
- Laboratory for Surface Technology and Tribology, Department of Mechanics of Solids, Surfaces and Systems (MS3), Faculty of Engineering Technology, University of Twente, Postbox 217, 7500 AE Enschede, the Netherlands
| | - E.E.G. Hekman
- Biomedical Device Design and Production Lab, Department of Biomechanical Engineering (BE), Faculty of Engineering Technology, University of Twente, Postbox 217, 7500 AE Enschede, the Netherlands
| | - E. van der Heide
- Laboratory for Surface Technology and Tribology, Department of Mechanics of Solids, Surfaces and Systems (MS3), Faculty of Engineering Technology, University of Twente, Postbox 217, 7500 AE Enschede, the Netherlands
| | - D.T.A. Matthews
- Laboratory for Surface Technology and Tribology, Department of Mechanics of Solids, Surfaces and Systems (MS3), Faculty of Engineering Technology, University of Twente, Postbox 217, 7500 AE Enschede, the Netherlands
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9
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Song G, Gosain AK, Buganza Tepole A, Rhee K, Lee T. Exploring uncertainty in hyper-viscoelastic properties of scalp skin through patient-specific finite element models for reconstructive surgery. Comput Methods Biomech Biomed Engin 2024:1-15. [PMID: 38339988 DOI: 10.1080/10255842.2024.2313067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/10/2024] [Indexed: 02/12/2024]
Abstract
Understanding skin responses to external forces is crucial for post-cutaneous flap wound healing. However, the in vivo viscoelastic behavior of scalp skin remains poorly understood. Personalized virtual surgery simulations offer a way to study tissue responses in relevant 3D geometries. Yet, anticipating wound risk remains challenging due to limited data on skin viscoelasticity, which hinders our ability to determine the interplay between wound size and stress levels. To bridge this gap, we reexamine three clinical cases involving scalp reconstruction using patient-specific geometric models and employ uncertainty quantification through a Monte Carlo simulation approach to study the effect of skin viscoelasticity on the final stress levels from reconstructive surgery. Utilizing the generalized Maxwell model via the Prony series, we can parameterize and efficiently sample a realistic range of viscoelastic response and thus shed light on the influence of viscoelastic material uncertainty in surgical scenarios. Our analysis identifies regions at risk of wound complications based on reported threshold stress values from the literature and highlights the significance of focusing on long-term responses rather than short-term ones.
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Affiliation(s)
- Gyohyeon Song
- Department of Intelligent Robotics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Arun K Gosain
- Surgery (Pediatric Surgery), Plastic Surgery, Lurie Children's Hospital of Chicago, Northwestern Feinberg School of Medicine, Chicago 60611, IL, United States
| | - Adrian Buganza Tepole
- Department of Mechanical Engineering, Purdue University, West Lafayette 47907, IN, United States
| | - Kyehan Rhee
- Department of Mechanical Engineering, Myongji University, Yongin, 17058, Republic of Korea
| | - Taeksang Lee
- Department of Mechanical Engineering, Myongji University, Yongin, 17058, Republic of Korea
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10
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Lin CY, Sugerman GP, Kakaletsis S, Meador WD, Buganza AT, Rausch MK. Sex- and age-dependent skin mechanics-A detailed look in mice. Acta Biomater 2024; 175:106-113. [PMID: 38042263 DOI: 10.1016/j.actbio.2023.11.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/28/2023] [Accepted: 11/21/2023] [Indexed: 12/04/2023]
Abstract
Skin aging is of immense societal and, thus, scientific interest. Because mechanics play a critical role in skin's function, a plethora of studies have investigated age-induced changes in skin mechanics. Nonetheless, much remains to be learned about the mechanics of aging skin. This is especially true when considering sex as a biological variable. In our work, we set out to answer some of these questions using mice as a model system. Specifically, we combined mechanical testing, histology, collagen assays, and two-photon microscopy to identify age- and sex-dependent changes in skin mechanics and to relate them to structural, microstructural, and compositional factors. Our work revealed that skin stiffness, thickness, and collagen content all decreased with age and were sex dependent. Interestingly, sex differences in stiffness were age induced. We hope our findings not only further our fundamental understanding of skin aging but also highlight both age and sex as important variables when conducting studies on skin mechanics. STATEMENT OF SIGNIFICANCE: Our work addresses the question, "How do sex and age affect the mechanics of skin?" Answering this question is of both scientific and societal importance. We do so in mice as a model system. Thereby, we hope to add clarity to a body of literature that appears divided on the effect of both factors. Our findings have important implications for those studying age and sex differences, especially in mice as a model system.
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Affiliation(s)
- Chien-Yu Lin
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Gabriella P Sugerman
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Sotirios Kakaletsis
- Department of Aerospace Engineering & Engineering Mechanics, The University of Texas at Austin, Austin, TX, USA
| | - William D Meador
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Adrian T Buganza
- Department of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Manuel K Rausch
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA; Department of Aerospace Engineering & Engineering Mechanics, The University of Texas at Austin, Austin, TX, USA; Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, TX, USA.
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11
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Huang F, Wang X, Zhang M, Wang L, Wang Y, Hu Y, Dong T, Wei P. Correlating facial skin parameters with age and gender in population of Shaanxi Province, China. J Cosmet Dermatol 2023. [PMID: 38093505 DOI: 10.1111/jocd.16113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 11/13/2023] [Accepted: 11/21/2023] [Indexed: 01/13/2024]
Abstract
OBJECTIVE This study was designed to comprehensively evaluate the changes in facial skin biophysical parameters with age, as well the influence of gender differences in populations of Shaanxi Province, China. METHODS Fourteen skin parameters, including stratum corneum hydration (SCH), transdermal water loss (TEWL), erythema, melanin, R0, R2, R5, R7, F4, gloss, skin surface pH, skin erythema index (a*), wrinkle length, and sebum, were measured by noninvasive instruments in 481 volunteers from Shaanxi Province. Spearman correlation analysis was performed to analyze the relationship between skin parameters and age. Additionally, skin parameters were analyzed for different age groups and different genders. RESULTS The results of the study showed a linear decrease in skin surface pH and sebum content with age, and the skin elasticity parameters R0, R2, R5, and R7 decreased significantly at the age of 54-65 years. Wrinkle length showed a linear and increase with age. R5 showed a weak negative correlation with age, R2, R7, and sebum content showed a moderate negative correlation, while wrinkle length showed a strong positive correlation. Considering the effect of gender on skin parameters, the results showed that SCH and gloss were lower in men than in women, while TEWL, erythema, melanin, wrinkle length, and sebum were higher than in women. However, there was no difference in skin elasticity between them. CONCLUSION The facial skin parameters, especially for the wrinkle length, exhibited the strong correlation relationship with ages in Shaanxi Province. Meanwhile, most skin parameters show significant differences with gender, which can provide a reference for future research and development in the field of cosmetics.
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Affiliation(s)
- Fengyu Huang
- College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China
| | - Xin Wang
- Shaanxi United Nations Test Evaluation Technology Co. Ltd., Xi'an, China
| | - Mengmeng Zhang
- College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China
| | - Lifang Wang
- Shaanxi Provincial Institute of Food and Drug Inspection Xi'an, Xi'an, China
| | - Yanfeng Wang
- Shaanxi United Nations Test Evaluation Technology Co. Ltd., Xi'an, China
| | - Yong Hu
- College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China
| | - Taiwei Dong
- College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China
| | - Peifeng Wei
- College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China
- The Second Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China
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12
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Margara A, Haykal D, Musella D, Bellia G, Boriani F. Hyaluronan Hybrid Cooperative Complexes Injection as a Biostimulation for Postobese Skin Laxity in the Arm: A Histopathologic Study. Aesthet Surg J Open Forum 2023; 6:ojad110. [PMID: 38887212 PMCID: PMC11181863 DOI: 10.1093/asjof/ojad110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024] Open
Abstract
Background The Hybrid Cooperative Complexes of high and low molecular weight hyaluronic acids (HHCC) improve skin structure and bioactivity. Massive weight loss damages cellular composition and morphological structure of skin. An injective treatment of postobese skin consisting of HHCC may have a role in counteracting these histopathological alterations. Objectives To analyze the histological effects of HHCC injection in the cutaneous tissues of massive weight loss patients suffering from arm laxity. Methods Nine ex-obese patients with postweight-loss-related arm laxity and ptosis requiring brachioplasty were prospectively recruited at the first author's department. HHCC injection was performed on only 1 arm, which included 2 injective sessions separated by 30 days. One month posttreatment, patients underwent a bilateral brachioplasty, and the surgical specimens were histologically examined, searching for any variation in the cutaneous connective tissue following injections. Histology on treated specimens showed a statistically significant increased density of elastic fibers along with a lower fragmentation of the same fibers compared to the untreated tissue. Fibroblasts demonstrated a swollen appearance as if involved in a bioactivation process. Results Treatment with HHCC increases the number of elastin fibers and determines a more regular elastin deposition and architecture, as well as the bioactivation of fibroblasts. The contralateral untreated area showed an irregular structure with elastosis and elastolysis. Conclusions More studies are necessary, but histologically proven benefits are demonstrated in the HHCC-treated skins when compared with basal controlateral skin. These data support the use of HHCC formulations for the treatment of postobese skin laxity. Level of Evidence 5
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Affiliation(s)
| | - Diala Haykal
- Corresponding Author: Dr Diala Haykal, 49 Ter Rue de Paris, 91120 Palaiseau, France. E-mail: ; Instagram: @centre_laser_palaiseau; Twitter: @drdialahaykal
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13
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Roth S. Thoughts and perspectives on biomechanical numerical models under impacts: Are women forgotten from research? Proc Inst Mech Eng H 2023; 237:1122-1138. [PMID: 37702375 DOI: 10.1177/09544119231195182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
The present paper explores a series of articles in the literature which deal with impact biomechanics of the head and thorax/abdomen segments, investigating the "sex specific properties/data" used in the studies. Statements in these studies are analyzed and point out, the use of male or female subjects for the developments of finite element models and their validation against experimental data. The present analysis raises the question about "androcentrism," and how biomechanical engineering findings and the design of the derived protecting devices are focused on male subjects.
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Affiliation(s)
- Sebastien Roth
- Laboratoire Interdisciplinaire Carnot de Bourgogne, site Université de Technologie de Belfort-Montbéliard (UTBM), UMR CNRS 6303/Univ. Bourgogne Franche-Comte (UBFC), Belfort, France
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14
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Lin CY, Sugerman GP, Kakaletsis S, Meador WD, Buganza AT, Rausch MK. Sex- and Age-dependent Skin Mechanics - A Detailed Look in Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.08.531781. [PMID: 36945509 PMCID: PMC10028869 DOI: 10.1101/2023.03.08.531781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Skin aging is of immense societal and, thus, scientific interest. Because mechanics play a critical role in skin's function, a plethora of studies have investigated age-induced changes in skin mechanics. Nonetheless, much remains to be learned about the mechanics of aging skin. This is especially true when considering sex as a biological variable. In our work, we set out to answer some of these questions using mice as a model system. Specifically, we combined mechanical testing, histology, collagen assays, and two-photon microscopy to identify age- and sex-dependent changes in skin mechanics and to relate them to structural, microstructural, and compositional factors. Our work revealed that skin stiffness, thickness, and collagen content all decreased with age and were sex dependent. Interestingly, sex differences in stiffness were age induced. We hope our findings not only further our fundamental understanding of skin aging but also highlight both age and sex as important variables when conducting studies on skin mechanics.
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Affiliation(s)
- Chien-Yu Lin
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Gabriella P Sugerman
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Sotirios Kakaletsis
- Department of Aerospace Engineering & Engineering Mechanics, The University of Texas at Austin, Austin, Texas, USA
| | - William D Meador
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Adrian T Buganza
- Department of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Manuel K Rausch
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
- Department of Aerospace Engineering & Engineering Mechanics, The University of Texas at Austin, Austin, Texas, USA
- Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, Texas, USA
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15
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Yeni B, Dermietzel A, Varnava C, Wiebringhaus P, Aitzetmueller M, Klietz ML, Hirsch T, Kueckelhaus M. Biomechanische Eigenschaften transgener Haut nach lebensrettender Regeneration der Epidermis durch kombinierte Gen- und Stammzelltherapie. J Dtsch Dermatol Ges 2023; 21:245-254. [PMID: 36929542 DOI: 10.1111/ddg.14978_g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 11/23/2022] [Indexed: 03/18/2023]
Affiliation(s)
- Burcu Yeni
- Abteilung für Plastische und Rekonstruktive Chirurgie, Institut für Muskuloskelettale Medizin, Universitätsklinikum Münster
- Abteilung für Plastische, Rekonstruktive und Ästhetische Chirurgie, Handchirurgie, Fachklinik Hornheide, Münster
| | - Alexander Dermietzel
- Abteilung für Plastische und Rekonstruktive Chirurgie, Institut für Muskuloskelettale Medizin, Universitätsklinikum Münster
- Abteilung für Plastische, Rekonstruktive und Ästhetische Chirurgie, Handchirurgie, Fachklinik Hornheide, Münster
- Abteilung für Plastische Chirurgie, Klinik für Unfall-, Hand- und Wiederherstellungschirurgie, Universitätsklinikum Münster
| | - Charalampos Varnava
- Abteilung für Plastische und Rekonstruktive Chirurgie, Institut für Muskuloskelettale Medizin, Universitätsklinikum Münster
- Abteilung für Plastische, Rekonstruktive und Ästhetische Chirurgie, Handchirurgie, Fachklinik Hornheide, Münster
- Abteilung für Plastische Chirurgie, Klinik für Unfall-, Hand- und Wiederherstellungschirurgie, Universitätsklinikum Münster
| | - Philipp Wiebringhaus
- Abteilung für Plastische und Rekonstruktive Chirurgie, Institut für Muskuloskelettale Medizin, Universitätsklinikum Münster
- Abteilung für Plastische, Rekonstruktive und Ästhetische Chirurgie, Handchirurgie, Fachklinik Hornheide, Münster
- Abteilung für Plastische Chirurgie, Klinik für Unfall-, Hand- und Wiederherstellungschirurgie, Universitätsklinikum Münster
| | - Matthias Aitzetmueller
- Abteilung für Plastische und Rekonstruktive Chirurgie, Institut für Muskuloskelettale Medizin, Universitätsklinikum Münster
- Abteilung für Plastische, Rekonstruktive und Ästhetische Chirurgie, Handchirurgie, Fachklinik Hornheide, Münster
- Abteilung für Plastische Chirurgie, Klinik für Unfall-, Hand- und Wiederherstellungschirurgie, Universitätsklinikum Münster
| | - Marie-Luise Klietz
- Abteilung für Plastische und Rekonstruktive Chirurgie, Institut für Muskuloskelettale Medizin, Universitätsklinikum Münster
- Abteilung für Plastische, Rekonstruktive und Ästhetische Chirurgie, Handchirurgie, Fachklinik Hornheide, Münster
- Abteilung für Plastische Chirurgie, Klinik für Unfall-, Hand- und Wiederherstellungschirurgie, Universitätsklinikum Münster
| | - Tobias Hirsch
- Abteilung für Plastische und Rekonstruktive Chirurgie, Institut für Muskuloskelettale Medizin, Universitätsklinikum Münster
- Abteilung für Plastische, Rekonstruktive und Ästhetische Chirurgie, Handchirurgie, Fachklinik Hornheide, Münster
- Abteilung für Plastische Chirurgie, Klinik für Unfall-, Hand- und Wiederherstellungschirurgie, Universitätsklinikum Münster
| | - Maximilian Kueckelhaus
- Abteilung für Plastische und Rekonstruktive Chirurgie, Institut für Muskuloskelettale Medizin, Universitätsklinikum Münster
- Abteilung für Plastische, Rekonstruktive und Ästhetische Chirurgie, Handchirurgie, Fachklinik Hornheide, Münster
- Abteilung für Plastische Chirurgie, Klinik für Unfall-, Hand- und Wiederherstellungschirurgie, Universitätsklinikum Münster
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16
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Yeni B, Dermietzel A, Varnava C, Wiebringhaus P, Aitzetmueller M, Klietz ML, Hirsch T, Kueckelhaus M. Transgenic skin biomechanical properties following first lifesaving epidermal regeneration using combined gene and cell therapy. J Dtsch Dermatol Ges 2023; 21:245-252. [PMID: 36772919 DOI: 10.1111/ddg.14978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 11/23/2022] [Indexed: 02/12/2023]
Abstract
BACKGROUND In 2017, we reported the first life-saving regeneration of virtually an entire epidermis by combined gene and stem cell therapy. Recently, we demonstrated excellent long-term stability of this transgenic epidermis. Skin quality in this experimental approach and its potential application in other conditions were elucidated here regarding long-term outcomes of biomechanical properties. PATIENTS AND METHODS Analysis of biomechanical properties including skin elasticity, anisotropy and friction was performed on multiple body sites 24, 36 and 60 months following transplantation. Firstly, the sites were matched against and compared to remaining stable non-transgenic areas as well as to a control group of 13 healthy subjects. Parameters for skin elasticity, deformation and friction were assessed non-invasively. RESULTS Biomechanical properties of the transgenic epidermis showed encouraging results in comparison to both the remaining stable non-transgenic skin as well as healthy controls. Skin elasticity was comparable to the controls. Skin friction showed some decrease in both transgenic and non-transgenic areas as compared to the controls. CONCLUSIONS The excellent functional outcomes of the transgenic epidermis demonstrate stable long-term results of this novel combined gene and stem cell therapy for epidermal regeneration. Thus, other applications for this technology, such as treatment of specific burns, should be explored.
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Affiliation(s)
- Burcu Yeni
- Department of Plastic and Reconstructive Surgery, Institute of Musculoskeletal Medicine, University Hospital Muenster, Muenster, Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Fachklinik Hornheide, Muenster, Germany
| | - Alexander Dermietzel
- Department of Plastic and Reconstructive Surgery, Institute of Musculoskeletal Medicine, University Hospital Muenster, Muenster, Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Fachklinik Hornheide, Muenster, Germany
- Division of Plastic Surgery, Department of Trauma, Hand and Reconstructive Surgery, University Hospital Muenster, Muenster, Germany
| | - Charalampos Varnava
- Department of Plastic and Reconstructive Surgery, Institute of Musculoskeletal Medicine, University Hospital Muenster, Muenster, Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Fachklinik Hornheide, Muenster, Germany
- Division of Plastic Surgery, Department of Trauma, Hand and Reconstructive Surgery, University Hospital Muenster, Muenster, Germany
| | - Philipp Wiebringhaus
- Department of Plastic and Reconstructive Surgery, Institute of Musculoskeletal Medicine, University Hospital Muenster, Muenster, Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Fachklinik Hornheide, Muenster, Germany
- Division of Plastic Surgery, Department of Trauma, Hand and Reconstructive Surgery, University Hospital Muenster, Muenster, Germany
| | - Matthias Aitzetmueller
- Department of Plastic and Reconstructive Surgery, Institute of Musculoskeletal Medicine, University Hospital Muenster, Muenster, Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Fachklinik Hornheide, Muenster, Germany
- Division of Plastic Surgery, Department of Trauma, Hand and Reconstructive Surgery, University Hospital Muenster, Muenster, Germany
| | - Marie-Luise Klietz
- Department of Plastic and Reconstructive Surgery, Institute of Musculoskeletal Medicine, University Hospital Muenster, Muenster, Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Fachklinik Hornheide, Muenster, Germany
- Division of Plastic Surgery, Department of Trauma, Hand and Reconstructive Surgery, University Hospital Muenster, Muenster, Germany
| | - Tobias Hirsch
- Department of Plastic and Reconstructive Surgery, Institute of Musculoskeletal Medicine, University Hospital Muenster, Muenster, Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Fachklinik Hornheide, Muenster, Germany
- Division of Plastic Surgery, Department of Trauma, Hand and Reconstructive Surgery, University Hospital Muenster, Muenster, Germany
| | - Maximilian Kueckelhaus
- Department of Plastic and Reconstructive Surgery, Institute of Musculoskeletal Medicine, University Hospital Muenster, Muenster, Germany
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Fachklinik Hornheide, Muenster, Germany
- Division of Plastic Surgery, Department of Trauma, Hand and Reconstructive Surgery, University Hospital Muenster, Muenster, Germany
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17
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Beatty MW, Wee AG, Marx DB, Ridgway L, Simetich B, De Sousa TC, Vakilzadian K, Schulte J. Viscoelastic Properties of Human Facial Skin and Comparisons with Facial Prosthetic Elastomers. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2023. [PMID: 36903138 PMCID: PMC10004410 DOI: 10.3390/ma16052023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/23/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Prosthesis discomfort and a lack of skin-like quality is a source of patient dissatisfaction with facial prostheses. To engineer skin-like replacements, knowledge of the differences between facial skin properties and those for prosthetic materials is essential. This project measured six viscoelastic properties (percent laxity, stiffness, elastic deformation, creep, absorbed energy, and percent elasticity) at six facial locations with a suction device in a human adult population equally stratified for age, sex, and race. The same properties were measured for eight facial prosthetic elastomers currently available for clinical usage. The results showed that the prosthetic materials were 1.8 to 6.4 times higher in stiffness, 2 to 4 times lower in absorbed energy, and 2.75 to 9 times lower in viscous creep than facial skin (p < 0.001). Clustering analyses determined that facial skin properties fell into three groups-those associated with body of ear, cheek, and remaining locations. This provides baseline information for designing future replacements for missing facial tissues.
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Affiliation(s)
- Mark W. Beatty
- Research Service, VA Nebraska-Western Iowa Healthcare System, 4101 Woolworth Avenue, Omaha, NE 68105, USA
- Department of Adult Restorative Dentistry, University of Nebraska Medical Center College of Dentistry, 4000 East Campus Loop South, Lincoln, NE 68583, USA
| | - Alvin G. Wee
- Research Service, VA Nebraska-Western Iowa Healthcare System, 4101 Woolworth Avenue, Omaha, NE 68105, USA
- Department of Restorative Sciences, University of Minnesota School of Dentistry, Malcolm Moos Health Sciences Tower, 515 Delaware Street SE, Minneapolis, MN 55455, USA
| | - David B. Marx
- Department of Statistics, 340 Hardin Hall, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Lauren Ridgway
- Formerly Department of Prosthodontics, Creighton University School of Dentistry, 2109 Cuming Street, Omaha, NE 68102, USA
| | - Bobby Simetich
- Department of Adult Restorative Dentistry, University of Nebraska Medical Center College of Dentistry, 4000 East Campus Loop South, Lincoln, NE 68583, USA
| | - Thiago Carvalho De Sousa
- Department of Dentistry, School of Health Sciences, University of Brasilia (UnB), Brasilia 70910-900, Brazil
| | - Kevin Vakilzadian
- Private Practice, Pine Ridge Dental, 8545 Executive Woods Drive Suite #2, Lincoln, NE 68512, USA
| | - Joel Schulte
- Process Engineer, GSK Consumer Healthcare, 1401 Cornhusker Highway, Lincoln, NE 68517, USA
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18
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Arora G, Khandpur S, Bansal A, Shetty B, Aggarwal S, Saha S, Sachdeva S, Gupta M, Sharma A, Monalisa K, Bhandari M, Bagrodia A. Current understanding of frictional dermatoses: A review. Indian J Dermatol Venereol Leprol 2023; 89:170-188. [PMID: 36461803 DOI: 10.25259/ijdvl_519_2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 10/01/2021] [Indexed: 11/11/2022]
Abstract
Human skin is continually exposed to internal and external forces, dynamic as well as static. The skin is normally flexible and can resist mechanical trauma due to friction, pressure, vibration, suction and laceration to a considerable degree. However, an excess of these forces can abnormally affect the structure and function of the skin, setting the stage for the development of a skin disorder. Repetitive trauma can cause lichenification, hyperpigmentation, erythema, scaling, fissuring, blisters, ulceration and chronic alterations. Frictional dermatoses is an under-recognised entity with no clear-cut definition and encompasses a variety of terms such as frictional dermatitis, frictional melanosis, frictional pigmentary dermatoses and certain other named entities, many of which are confusing. The authors propose to define frictional dermatoses as 'a group of disorders caused by repetitive trauma to the skin as a result of friction of varied aetiology which can have a wide range of cutaneous manifestations depending on the type of insult.' The exact prevalence of frictional dermatoses as a separate entity is unknown. Authors who conducted this review include a group of dermatologists and post graduate students from various institutions. Literature was reviewed through PubMed, Medscape, Medline, ResearchGate and Google Scholar using the terms 'frictional dermatitis,' 'friction and skin,' 'dermatoses and culture,' 'clothing dermatitis,' 'friction melanosis,' 'PPE induced dermatoses in COVID-19 era,' etc. A total of 122 articles were reviewed and 100 articles among them were shortlisted and included in the study, after removing duplications. The review was followed up with further deliberation which resulted in the formulation of a new definition and classification of frictional dermatoses taking into account the morphology, histopathological characteristics, anatomical region affected and the major predisposing factors. The rising incidence of mechanical dermatoses in the COVID-19 era was also emphasised.
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Affiliation(s)
- Gulhima Arora
- Mehektagul Dermaclinic, All India Institute of Medical Sciences, New Delhi, India
| | - Sujay Khandpur
- Department of Dermatology and Venereology, All India Institute of Medical Sciences, New Delhi, India
| | - Anuva Bansal
- Department of Dermatology and Venereology, Maulana Azad Medical College, New Delhi, India
| | - Bhavishya Shetty
- Department of Dermatology and Venereology, Maulana Azad Medical College, New Delhi, India
| | - Sonia Aggarwal
- Department of Dermatology and Venereology, University College of Medical Sciences, New Delhi, India
| | - Sushobhan Saha
- Department of Dermatology and Venereology, University College of Medical Sciences, New Delhi, India
| | - Soumya Sachdeva
- Department of Dermatology and Venereology, Atal Bihari Vajpayee Institute of Medical Sciences and Dr. RML Hospital, New Delhi, India
| | - Meghna Gupta
- Department of Dermatology and Venereology, Maulana Azad Medical College, New Delhi, India
| | - Ananya Sharma
- Department of Dermatology and Venereology, All India Institute of Medical Sciences, New Delhi, India
| | - Kumari Monalisa
- Department of Dermatology and Venereology, Maulana Azad Medical College, New Delhi, India
| | - Molisha Bhandari
- Department of Dermatology and Venereology, Vardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
| | - Anjali Bagrodia
- Department of Dermatology and Venereology, Maulana Azad Medical College, New Delhi, India
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Jeon B, Jung HG, Lee SW, Lee G, Shim JH, Kim MO, Kim BJ, Kim SH, Lee H, Lee SW, Yoon DS, Jo SJ, Choi TH, Lee W. Melanoma Detection by AFM Indentation of Histological Specimens. Diagnostics (Basel) 2022; 12:1736. [PMID: 35885640 PMCID: PMC9323377 DOI: 10.3390/diagnostics12071736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/29/2022] [Accepted: 07/15/2022] [Indexed: 11/16/2022] Open
Abstract
Melanoma is visible unlike other types of cancer, but it is still challenging to diagnose correctly because of the difficulty in distinguishing between benign nevus and melanoma. We conducted a robust investigation of melanoma, identifying considerable differences in local elastic properties between nevus and melanoma tissues by using atomic force microscopy (AFM) indentation of histological specimens. Specifically, the histograms of the elastic modulus of melanoma displayed multimodal Gaussian distributions, exhibiting heterogeneous mechanical properties, in contrast with the unimodal distributions of elastic modulus in the benign nevus. We identified this notable signature was consistent regardless of blotch incidence by sex, age, anatomical site (e.g., thigh, calf, arm, eyelid, and cheek), or cancer stage (I, IV, and V). In addition, we found that the non-linearity of the force-distance curves for melanoma is increased compared to benign nevus. We believe that AFM indentation of histological specimens may technically complement conventional histopathological analysis for earlier and more precise melanoma detection.
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Affiliation(s)
- Byoungjun Jeon
- Interdisciplinary Program for Bioengineering, Graduate School, Seoul National University, Seoul 08826, Korea;
| | - Hyo Gi Jung
- School of Biomedical Engineering, Korea University, Seoul 02841, Korea; (H.G.J.); (S.W.L.); (D.S.Y.)
- Interdisciplinary Program in Precision Public Health, Korea University, Seoul 02841, Korea
| | - Sang Won Lee
- School of Biomedical Engineering, Korea University, Seoul 02841, Korea; (H.G.J.); (S.W.L.); (D.S.Y.)
| | - Gyudo Lee
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 30019, Korea;
- Interdisciplinary Graduate Program for Artificial Intelligence Smart Convergence Technology, Korea University, Sejong 30019, Korea
| | - Jung Hee Shim
- Department of Plastic and Reconstructive Surgery, Research Services, Seoul National University Bundang Hospital, Seongnam 13620, Korea;
| | - Mi Ok Kim
- Department of Plastic and Reconstructive Surgery, Institute of Human Environment Interface Biology, Seoul National University College of Medicine, Seoul 03087, Korea; (M.O.K.); (B.J.K.)
| | - Byung Jun Kim
- Department of Plastic and Reconstructive Surgery, Institute of Human Environment Interface Biology, Seoul National University College of Medicine, Seoul 03087, Korea; (M.O.K.); (B.J.K.)
| | - Sang-Hyon Kim
- Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu 41931, Korea;
| | - Hyungbeen Lee
- Department of Biomedical Engineering, Yonsei University, Wonju 26493, Korea; (H.L.); (S.W.L.)
- R&D Center of Curigin Ltd., Seoul 04778, Korea
| | - Sang Woo Lee
- Department of Biomedical Engineering, Yonsei University, Wonju 26493, Korea; (H.L.); (S.W.L.)
| | - Dae Sung Yoon
- School of Biomedical Engineering, Korea University, Seoul 02841, Korea; (H.G.J.); (S.W.L.); (D.S.Y.)
- Interdisciplinary Program in Precision Public Health, Korea University, Seoul 02841, Korea
- Astrion Inc., Seoul 02841, Korea
| | - Seong Jin Jo
- Department of Dermatology, Seoul National University College of Medicine, Seoul 03087, Korea
| | - Tae Hyun Choi
- Department of Plastic and Reconstructive Surgery, Institute of Human Environment Interface Biology, Seoul National University College of Medicine, Seoul 03087, Korea; (M.O.K.); (B.J.K.)
| | - Wonseok Lee
- Department of Electrical Engineering, Korea National University of Transportation, Chungju 27469, Korea
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20
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OLDER PATIENTS AND PATIENTS WITH SEVERE ARTERIOSCLEROSIS ARE LESS LIKELY TO DEVELOP KELOIDS AND HYPERTROPHIC SCARS AFTER THORACIC MIDLINE INCISION: A SURVEY-BASED ANALYSIS OF 328 CASES. Plast Reconstr Surg 2022; 150:659-669. [PMID: 35787599 DOI: 10.1097/prs.0000000000009451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Surgery is a well-known trigger of keloid and hypertrophic scarring. Sternotomy scars are subject to high skin tension, which is also known to promote pathological scarring. This suggests that sternotomies in adults associate with high pathological-scarring rates, which is also our anecdotal experience. However, this notion has never been formally examined. Therefore, we conducted a survey-based cohort study of patients who had undergone a sternotomy. STUDY DESIGN All consecutive Japanese adults (≥18 years) who underwent cardiovascular surgery with sternotomy in 2014-2017 were identified in 2019 by chart review and sent a questionnaire. Respondents formed the study cohort. The questionnaire presented randomly-ordered photos of representative mature, keloid, and hypertrophic scars and asked the patients to choose the image that best resembled their midline scar when it was particularly noticeable. The incidence of self-reported pathological scarring (keloids and hypertrophic scars were grouped together) and the patient demographic (age and sex) and clinical characteristics (e.g. intima media thickness of the left and right common and internal carotid arteries) that associated with pathological scarring were determined. RESULTS Of the 548 sternotomy patients, 328 (mean age, 67 years; 68.0% male) responded (60% response rate). Of these, 195 (59.5%) reported they had a pathological scar. Compared to mature-scar patients, pathological-scar patients had lower mean age (65 vs. 69 years, p=0.0002) and intima-media thickness (0.92 vs. 1.05 mm, p=0.028). CONCLUSION Sternotomy was associated with a high rate of pathological scarring. An older age and arteriosclerosis were associated with less pathological scarring.
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21
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Lv J, Yang S, Lv M, Lv J, Sui Y, Guo S. Protective roles of mesenchymal stem cells on skin photoaging: A narrative review. Tissue Cell 2022; 76:101746. [PMID: 35182986 DOI: 10.1016/j.tice.2022.101746] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/17/2022] [Accepted: 01/25/2022] [Indexed: 12/30/2022]
Abstract
Skin is a natural barrier of human body and a visual indicator of aging process. Exposure to ultraviolet (UV) radiation in the sunlight may injure the skin tissues and cause local damage. Besides, it is reported that repetitive or long-term exposure to UV radiation may reduce the collagen production, change the normal skin structure and cause premature skin aging. This is termed "photoaging". The classical symptoms of photoaging include increased roughness, wrinkle formation, mottled pigmentation or even precancerous changes. Mesenchymal stem cells (MSCs) are a kind of cells with the ability of self-renewal and multidirectional differentiation into many types of cells, like adipocytes, osteoblasts and chondrocytes. Researchers have explored diverse pharmacological actions of MSCs because of their migratory activity, paracrine actions and immunoregulation effects. In recent years, the huge potential of MSCs in preventing skin from photoaging has gained wide attention. MSCs exert their beneficial effects on skin photoaging via antioxidant effect, anti-apoptotic/anti-inflammatory effect, reduction of matrix metalloproteinases (MMPs) and activation of dermal fibroblasts proliferation. MSCs and MSC related products have demonstrated huge potential in the treatment of skin photoaging. This narrative review concisely sums up the recent research developments on the roles of MSCs in protection against photoaging and highlights the enormous potential of MSCs in skin photoaging treatment.
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Affiliation(s)
- Jiacheng Lv
- Department of Plastic Surgery, The First Hospital of China Medical University, Shenyang, China
| | - Shude Yang
- Department of Plastic Surgery, The First Hospital of China Medical University, Shenyang, China
| | - Mengzhu Lv
- Department of Plastic Surgery, The First Hospital of China Medical University, Shenyang, China
| | - Jiarui Lv
- Department of Physiology, School of Life Science, China Medical University, Shenyang, China
| | - Yanan Sui
- Department of Ophthalmology, The Second Hospital of Dalian Medical University, Dalian, China
| | - Shu Guo
- Department of Plastic Surgery, The First Hospital of China Medical University, Shenyang, China.
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22
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Needleless administration of advanced therapies into the skin via the appendages using a hypobaric patch. Proc Natl Acad Sci U S A 2022; 119:e2120340119. [PMID: 35482922 PMCID: PMC9170139 DOI: 10.1073/pnas.2120340119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Needleless delivery into the skin would overcome a major barrier to efficient clinical utilization of advanced therapies such as nanomaterials and macromolecules. This study demonstrates that controlled skin stretching (in porcine, rat, and mouse models) using a patch comprising a hypobaric chamber, to open the skin appendages, can increase the permeability of the tissue and provide a means to enable direct delivery of advanced therapies directly into the skin without the use of a needle or injection system. This technology can facilitate the self-administration of therapeutics including vaccines, RNA, and antigens, thus improving the translation of these products into effective clinical use. Advanced therapies are commonly administered via injection even when they act within the skin tissue, and this increases the chances of off-target effects. Here we report the use of a skin patch containing a hypobaric chamber that induces skin dome formation to enable needleless delivery of advanced therapies directly into porcine, rat, and mouse skin. Finite element method modeling showed that the hypobaric chamber in the patch opened the skin appendages by 32%, thinned the skin, and compressed the appendage wall epithelia. These changes allowed direct delivery of an H1N1 vaccine antigen and a diclofenac nanotherapeutic into the skin. Fluorescence imaging and infrared mapping of the skin showed needleless delivery via the appendages. The in vivo utility of the patch was demonstrated by a superior immunoglobulin G response to the vaccine antigen in mice compared to intramuscular injection and a 70% reduction in rat paw swelling in vivo over 5 h with diclofenac without skin histology changes.
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Spagnoli A, Alberini R, Raposio E, Terzano M. Simulation and optimization of reconstructive surgery procedures on human skin. J Mech Behav Biomed Mater 2022; 131:105215. [DOI: 10.1016/j.jmbbm.2022.105215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/16/2022] [Accepted: 04/01/2022] [Indexed: 11/25/2022]
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Van Nuffel M, Meulyzer C, Gheysen B, Böhrer A, Anthonissen M, Van den Kerckhove E, Degreef I. Palmar skin elasticity measured by the Cutometer MPA 580 is decreased in mild Dupuytren's disease compared to healthy controls. HAND THERAPY 2022; 27:14-21. [PMID: 37904791 PMCID: PMC10584061 DOI: 10.1177/17589983211061616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 11/04/2021] [Indexed: 11/01/2023]
Abstract
Introduction Involvement of the palmar skin is often seen in patients with Dupuytren's disease (DD) with severe finger contractures. However, skin elasticity may be already decreased earlier in the disease. The Cutometer MPA 580 could provide an objective skin measurement tool to assess this decrease in elasticity. Linking objective skin measurements to functional outcome measures could lead to better prediction of disease progression. We set up a study to investigate if the Cutometer was able to detect differences in skin elasticity between patients with mild Dupuytren's disease and healthy controls. Methods A cross-sectional analytical study was performed. Three assessors measured skin elasticity (palmar hand) on two sites using the Cutometer on 30 patients with mild DD and 30 healthy controls. Student's t-test was used to evaluate differences in skin elasticity and a linear model to evaluate interactions between the groups and sites. Results Significant differences in skin elasticity were found between DD patients and controls, as well as differences based on the location examined. Discussion Similar to other skin conditions, the Cutometer MPA 580 was able to demonstrate a significant lower elasticity in the palmar skin in DD patients compared to healthy controls. A decrease in skin elasticity in different locations of the hand correlated with areas that often pose problems in the treatment of more severe DD. The Cutometer could potentially be a tool to identify these areas earlier in the disease.
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Affiliation(s)
- Maarten Van Nuffel
- Department of Medical Sciences, KU Leuven-University of Leuven; Hand Unit, Department of Orthopaedic Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Caroline Meulyzer
- Department of Rehabilitation Sciences, KU Leuven-University of Leuven; Department of Physical Medicine and Rehabilitation, University Hospitals Leuven, Leuven, Belgium
| | - Britt Gheysen
- Department of Rehabilitation Sciences, KU Leuven-University of Leuven; Department of Physical Medicine and Rehabilitation, University Hospitals Leuven, Leuven, Belgium
| | - Arne Böhrer
- Department of Rehabilitation Sciences, KU Leuven-University of Leuven; Department of Physical Medicine and Rehabilitation, University Hospitals Leuven, Leuven, Belgium
| | - Mieke Anthonissen
- Department of Rehabilitation Sciences, KU Leuven-University of Leuven; Department of Physical Medicine and Rehabilitation, University Hospitals Leuven, Leuven, Belgium
- Oscare, Organisation for Burns, Scar After-care and Research, Antwerp, Belgium
| | - Eric Van den Kerckhove
- Department of Rehabilitation Sciences, KU Leuven-University of Leuven; Department of Physical Medicine and Rehabilitation, University Hospitals Leuven, Leuven, Belgium
- Department of Plastic, Reconstructive and Hand Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Ilse Degreef
- Department of Medical Sciences, KU Leuven-University of Leuven; Hand Unit, Department of Orthopaedic Surgery, University Hospitals Leuven, Leuven, Belgium
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Dwivedi KK, Lakhani P, Kumar S, Kumar N. Effect of collagen fibre orientation on the Poisson's ratio and stress relaxation of skin: an ex vivo and in vivo study. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211301. [PMID: 35345435 PMCID: PMC8941416 DOI: 10.1098/rsos.211301] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
During surgical treatment skin undergoes extensive deformation, hence it must be able to withstand large mechanical stresses without damage. Therefore, understanding the mechanical properties of skin becomes important. A detailed investigation on the relationship between the three-dimensional deformation response of skin and its microstructure is conducted in the current study. This study also discloses the underlying science of skin viscoelasticity. Deformation response of skin is captured using digital image correlation, whereas micro-CT, scanning electron microscopy and atomic force microscopy are used for microstructure analysis. Skin shows a large lateral contraction and expansion (auxeticity) when stretched parallel and perpendicular to the skin tension lines, respectively. Large lateral contraction is a result of fluid exudation from the tissue, while large rotation of the stiff collagen fibres in the loading direction explains the skin auxeticity. During stress relaxation, lateral contraction and fluid effluxion from skin reveal that tissue volume loss is the intrinsic science of skin viscoelasticity. Furthermore, the results obtained from in vivo study on human skin show the relevance of the ex vivo study to physiological conditions and stretching of the skin during its treatments.
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Affiliation(s)
- Krashn Kumar Dwivedi
- Department of Biomedical Engineering, Indian Institute of Technology, Ropar, India
| | - Piyush Lakhani
- Department of Mechanical Engineering, Indian Institute of Technology, Ropar, India
| | - Sachin Kumar
- Department of Mechanical Engineering, Indian Institute of Technology, Ropar, India
| | - Navin Kumar
- Department of Biomedical Engineering, Indian Institute of Technology, Ropar, India
- Department of Mechanical Engineering, Indian Institute of Technology, Ropar, India
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Sree VD, Ardekani A, Vlachos P, Tepole AB. The biomechanics of autoinjector — Skin interactions during dynamic needle insertion. J Biomech 2022; 134:110995. [DOI: 10.1016/j.jbiomech.2022.110995] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 11/25/2022]
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Merrick C, Rosati R, Filingeri D. The role of friction on skin wetness perception during dynamic interactions between the human index fingerpad and materials of varying moisture content. J Neurophysiol 2022; 127:725-736. [PMID: 35044853 PMCID: PMC8897031 DOI: 10.1152/jn.00382.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mechanosensory inputs arising from dynamic interactions between the skin and moisture, such as when sliding a finger over a wet substrate, contribute to the perception of skin wetness. Yet, the exact relationship between the mechanical properties of a wet substrate, such as friction, and the resulting wetness perception remains to be established under naturalistic haptic interactions. We modeled the relationship between mechanical and thermal properties of substrates varying in moisture levels (0.49 × 10−4; 1.10 × 10−4; and 2.67 × 10−4 mL·mm−2), coefficient of friction (0.783, 0.848, 1.033, 0.839, 0.876, and 0.763), and maximum thermal transfer rate (Qmax, ranging from 511 to 1,260 W·m−2·K−1), and wetness perception arising from the index finger pad’s contact with such substrates. Forty young participants (20M/20F) performed dynamic interactions with 21 different stimuli using their index finger pad at a controlled angle, pressure, and speed. Participants rated their wetness perception using a 100-mm visual analog scale (very dry to very wet). Partial least squares regression analysis indicated that coefficient of friction explained only ∼11% of the variance in wetness perception, whereas Qmax and moisture content accounted for ∼22% and 18% of the variance, respectively. These parameters shared positive relationships with wetness perception, such that the greater the Qmax, moisture content, and coefficient of friction, the wetter the perception. We found no differences in wetness perception between males and females. Our findings indicate that although the friction of a wet substrate modulates wetness perception, it is still secondary to thermal parameters such as Qmax. NEW & NOTEWORTHY Our skin often interacts with wet materials, yet how their physical properties influence our experience of wetness remains poorly understood. We evaluated wetness perception following naturalistic haptic interactions with materials varying in moisture content, friction, optical profiles, and heat transfer rates. We show that although mechanical parameters can influence wetness perception, their role is secondary to that of thermal factors. These findings expand our understanding of multisensory integration and could guide innovation in healthcare product design.
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Affiliation(s)
- Charlotte Merrick
- THERMOSENSELAB, Environmental Ergonomics Research Centre, Loughborough Design School, grid.6571.5Loughborough University, Loughborough, United Kingdom
| | - Rodrigo Rosati
- Procter and Gamble Service GmbH, Frankfurt am Taunus, Germany
| | - Davide Filingeri
- THERMOSENSELAB, Skin Health Research Group, School of Health Science, University of Southampton, United Kingdom
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28
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Lynch B, Pageon H, Le Blay H, Brizion S, Bastien P, Bornschlögl T, Domanov Y. A mechanistic view on the aging human skin through ex vivo layer-by-layer analysis of mechanics and microstructure of facial and mammary dermis. Sci Rep 2022; 12:849. [PMID: 35039567 PMCID: PMC8764052 DOI: 10.1038/s41598-022-04767-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/31/2021] [Indexed: 01/09/2023] Open
Abstract
Age-related changes in skin mechanics have a major impact on the aesthetic perception of skin. The link between skin microstructure and mechanics is crucial for therapeutic and cosmetic applications as it bridges the micro- and the macro-scale. While our perception is governed by visual and tactile changes at the macroscopic scale, it is the microscopic scale (molecular assemblies, cells) that is targeted by topical treatments including active compounds and energies. We report here a large dataset on freshly excised human skin, and in particular facial skin highly relevant for cosmetics and aesthetic procedures. Detailed layer-by-layer mechanical analysis revealed significant age-dependent decrease in stiffness and elastic recoil of full-thickness skin from two different anatomical areas. In mammary skin, we found that the onset of mechanical degradation was earlier in the superficial papillary layer than in the deeper, reticular dermis. These mechanical data are linked with microstructural alterations observed in the collagen and elastic networks using staining and advanced imaging approaches. Our data suggest that with ageing, the earliest microstructural and mechanical changes occur in the top-most layers of dermis/skin and then propagate deeper, providing an opportunity for preventive topical treatments acting at the level of papillary dermis.
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Affiliation(s)
- Barbara Lynch
- L'Oréal Research and Innovation, Advanced Research, Aulnay-sous-Bois, France.
| | - Hervé Pageon
- L'Oréal Research and Innovation, Advanced Research, Aulnay-sous-Bois, France
| | - Heiva Le Blay
- L'Oréal Research and Innovation, Advanced Research, Aulnay-sous-Bois, France
| | - Sébastien Brizion
- L'Oréal Research and Innovation, Advanced Research, Aulnay-sous-Bois, France
| | - Philippe Bastien
- L'Oréal Research and Innovation, Advanced Research, Aulnay-sous-Bois, France
| | - Thomas Bornschlögl
- L'Oréal Research and Innovation, Advanced Research, Aulnay-sous-Bois, France
| | - Yegor Domanov
- L'Oréal Research and Innovation, Advanced Research, Aulnay-sous-Bois, France
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29
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Ficarella E, Natalicchio A, Spina R, Galantucci LM. Technological scouting of bi-material face masks: experimental analysis on real faces. PROCEDIA CIRP 2022; 110:354-359. [PMID: 35822103 PMCID: PMC9264979 DOI: 10.1016/j.procir.2022.06.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/29/2022]
Abstract
The need for personal protective equipment rapidly grew during the COVID-19. Companies had to face problems related to their products' sustainability, adherence, and comfortability. Designing a face mask with proper adherence and comfortability in wearing and breathing became a matter of great importance. In this work, the adherence of an innovative face mask and its comfortability were experimentally tested with real faces, considering the deformation of the mask and the soft facial tissues. A stereophotogrammetric acquisition was made of the face with the face mask during these tests. A comparison between the geometries of the face and the mask, undeformed and deformed, gave the respective deformations. The force applied by the mask to the face was calculated, measuring the elastic strain of the mask bands during wearing and the deformation.
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30
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Dwivedi KK, Lakhani P, Kumar S, Kumar N. A hyperelastic model to capture the mechanical behaviour and histological aspects of the soft tissues. J Mech Behav Biomed Mater 2021; 126:105013. [PMID: 34920323 DOI: 10.1016/j.jmbbm.2021.105013] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/10/2021] [Accepted: 11/27/2021] [Indexed: 11/19/2022]
Abstract
It is well established that the soft connective tissues show a nonlinear elastic response that comes from their microstructural arrangement. Tissues' microstructure alters with various physiological conditions and may affect their mechanical responses. Therefore, the accurate prediction of tissue's mechanical response is crucial for clinical diagnosis and treatments. Thus, a physically motivated and mathematically simplified model is required for the accurate prediction of tissues' mechanical and structural responses. This study explored the 'Exp-Ln' hyperelastic model (Khajehsaeid et al., 2013) to capture soft tissues' mechanical and histological behaviour. In this work, uniaxial tensile test data for the belly and back pig skin were extracted from the experiments performed in our laboratory, whereas uniaxial test data for other soft tissues (human skin, tendon, ligament, and aorta) were extracted from the literature. The 'Exp-Ln; and other hyperelastic models (e.g. Money Rivlin, Ogden, Yeoh, and Gent models) were fitted with these experimental data, and obtained results were compared between the models. These results show that the 'Exp-Ln' model could capture the mechanical behaviour of soft tissues more accurately than other hyperelastic models. This model was also found numerically stable for all modes and ranges of deformation. This study also investigated the link between 'Exp-Ln' material parameters and tissue's histological parameters. The histological parameters such as collagen content, fibre free length, crosslink density, and collagen arrangement were measured using staining and ATR-FTIR techniques. The material parameters were found statistically correlated with the histological parameters. Further, 'Exp-Ln' model was implemented in ABAQUS through the VUMAT subroutine, where the mechanical behaviour of various soft tissues was simulated for different modes of deformation. The finite element analysis results obtained using the 'Exp-Ln' model agreed with the experiments and were more accurate than other hyperelastic models. Overall, these results demonstrate the capability of 'Exp-Ln' model to predict the mechanical and structural responses of the soft tissues.
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Affiliation(s)
- Krashn Kr Dwivedi
- Department of Biomedical Engineering, Indian Institute of Technology Ropar, India
| | - Piyush Lakhani
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, India
| | - Sachin Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, India
| | - Navin Kumar
- Department of Biomedical Engineering, Indian Institute of Technology Ropar, India; Department of Mechanical Engineering, Indian Institute of Technology Ropar, India.
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31
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The Influence of Headform/Helmet Friction on Head Impact Biomechanics in Oblique Impacts at Different Tangential Velocities. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app112311318] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oblique impacts of the helmet against the ground are the most frequent scenarios in real-world motorcycle crashes. The combination of two factors that largely affect the results of oblique impact tests are discussed in this work. This study aims to quantify the effect of the friction at the interface between the headform and the interior of a motorcycle helmet at different magnitudes of tangential velocity. The helmeted headform, with low friction and high friction surface of the headform, was dropped against three oblique anvils at different impact velocities resulting in three different magnitudes of the tangential velocity (3.27 m/s, 5.66 m/s, 8.08 m/s) with the same normal component of the impact velocity (5.66 m/s). Three impact directions (front, left-side and right-side) and three repetitions per impact condition were tested resulting in 54 impacts. Tangential velocity variation showed little effect on the linear acceleration results. On the contrary, the rotational results showed that the effect of the headform’s surface depends on the magnitude of the tangential velocity and on the impact direction. These results indicate that a combination of low friction with low tangential velocities may result into underprediction of the rotational headform variables that would not be representative of real-world conditions.
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32
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Cha SY, Park SY, Lee JS, Lee KH, Kim JH, Fang Y, Shin SS. Efficacy of Dendrobium candidum polysaccharide extract as a moisturizer. J Cosmet Dermatol 2021; 21:3117-3126. [PMID: 34841665 DOI: 10.1111/jocd.14586] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/20/2021] [Indexed: 12/25/2022]
Abstract
INTRODUCTION This study investigated the role of natural polymers as moisturizers with low toxicity and biodegradability in the cosmetic and pharmaceutical industries. We isolated a polysaccharide extract from Dendrobium candidum (D. candidum) and determined its efficacy in skin hydration when used as an active cosmetic ingredient. METHODS The molecular weight distribution of D. candidum polysaccharides was analyzed via gel permeation chromatography (GPC). We performed real-time reverse transcription PCR (RT-PCR) and western blotting assays to investigate the physiological mechanism of the polysaccharides extracted from D. candidum (PDC). Based on in vitro data, the efficacy of PDC in improving skin condition was tested on the face of 21 volunteers. RESULTS The expression of filaggrin (FLG), caspase-14, and bleomycin hydrolase, which are the major components contributing to skin hydration, was significantly increased in the PDC-treated group. Further, the PDC upregulated the mRNA expression of occludin and claudin-1, which play a key role in epidermal barrier function. In addition, a topical application of PDC markedly increased skin hydration and improved trans-epidermal water loss (TEWL) and skin elasticity after 2 weeks. CONCLUSIONS It is the first study reporting the efficacy of PDC-mediated FLG mechanism associated with positive skin hydration. PDC can be used as an active ingredient in moisturizers. Long-term application of PDC-based moisturizers may result in significant improvement in elasticity and barrier function.
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Affiliation(s)
- So Yoon Cha
- HYUNDAI BIOLAND. Co., Ltd., Cheongju-si, Republic of Korea
| | - So Yeon Park
- HYUNDAI BIOLAND. Co., Ltd., Cheongju-si, Republic of Korea
| | - Jae Seok Lee
- HYUNDAI BIOLAND. Co., Ltd., Cheongju-si, Republic of Korea
| | - Kang Hyuk Lee
- HYUNDAI BIOLAND. Co., Ltd., Cheongju-si, Republic of Korea
| | | | | | - Song Seok Shin
- HYUNDAI BIOLAND. Co., Ltd., Cheongju-si, Republic of Korea
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Kim J, Yoo S, Kwon OS, Jeong ET, Lim JM, Park SG. Influence of quarantine mask use on skin characteristics: One of the changes in our life caused by the COVID-19 pandemic. Skin Res Technol 2021; 27:599-606. [PMID: 33369781 PMCID: PMC8359323 DOI: 10.1111/srt.12992] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 12/04/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND The influence of various environmental factors on skin properties is well known. However, there is a lack of research into the effect of quarantine masks on skin properties, even though the use of masks has significantly increased after the COVID-19 outbreak. Therefore, this study aimed to investigate the influence of mask use on skin properties. MATERIALS AND METHODS Twenty subjects were enrolled in this study. The subjects used approved quarantine masks for 6 hours a day for 2 weeks. We measured eight skin biophysical parameters: temperature, redness, pore volume, texture, elasticity, trans-epidermal water loss (TEWL), sebum content, and pH, and evaluated acne lesions before and after using quarantine masks. The evaluation was performed on the mask-wearing area of the face. RESULTS Skin temperature, redness, and TEWL increased significantly after a 6-hour mask use, while the sebum content increased marginally. Skin elasticity was reduced by the use of masks over 1 and 2 weeks, whereas the pore volume and the number of acne lesions increased after a 2-week mask use. The skin changes caused by mask use showed sex-based differences in the skin elasticity (after 6 hours), redness, and roughness (after 2 weeks). CONCLUSIONS The use of quarantine masks causes a change in the skin temperature, redness, and TEWL in the short term and in skin elasticity, pores, and acne in the long term. This study revealed that prolonged mask use could have negative effects on the skin.
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Affiliation(s)
| | - Suji Yoo
- LG Household & Health Care (LG H&H)SeoulKorea
| | - Oh Sun Kwon
- LG Household & Health Care (LG H&H)SeoulKorea
| | | | - Jun Man Lim
- LG Household & Health Care (LG H&H)SeoulKorea
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Gentile P, Garcovich S. Adipose-Derived Mesenchymal Stem Cells (AD-MSCs) against Ultraviolet (UV) Radiation Effects and the Skin Photoaging. Biomedicines 2021; 9:biomedicines9050532. [PMID: 34064624 PMCID: PMC8151305 DOI: 10.3390/biomedicines9050532] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/07/2021] [Accepted: 05/09/2021] [Indexed: 12/26/2022] Open
Abstract
The skin is a natural barrier against the ultraviolet (UV) radiation of sunlight. The long-term and/or repetitive exposure to the sunlight and related UV radiation may change the skin structure, decreasing collagen production, promoting premature skin aging, which is termed "photoaging". The signs of photoaging include wrinkle formation, mottled pigmentation, and/or cancerous changes. For many years, adipose-derived mesenchymal stem cells (AD-MSCs) and fat grafting (F-GRF) have been used to combat photoaging signs, wrinkles, loss of elasticity, and face soft tissue defects. Several studies have analyzed in vitro actions of AD-MSCs against photoaging's effects, thanks to their migratory activity, paracrine actions, and related in vivo-ex vivo outcomes. In fact, AD-MSCs act against skin photoaging in vitro via activation of dermal fibroblast proliferation, antioxidant effect, and matrix metalloproteinases (MMPs) reduction. In vivo and ex vivo outcomes regard the local injection of AD-MSCs, F-GRF, and/or enriched-F-GRF with AD-MSCs directly in the wrinkles and the face's soft tissue defects. This concise review summarizes the most recent in vitro, in vivo and ex vivo outcomes and developments on the effects of AD-MSCs and F-GRF against photoaging.
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Affiliation(s)
- Pietro Gentile
- Department of Surgical Science, Plastic and Reconstructive Surgery, Medical School, “Tor Vergata” University, 00133 Rome, Italy
- Scientific Director of Academy of International Regenerative Medicine & Surgery Societies (AIRMESS), 1201 Geneva, Switzerland
- Correspondence: ; Tel.: +39-3388-5154-79
| | - Simone Garcovich
- Institute of Dermatology, F. Policlinico Gemelli IRCSS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
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Deflorin C, Hohenauer E, Stoop R, van Daele U, Clijsen R, Taeymans J. Response to Vercelli et al. re: "Physical Management of Scar Tissue: A Systematic Review and Meta-Analysis". J Altern Complement Med 2021; 27:374-376. [PMID: 33826859 DOI: 10.1089/acm.2020.29089.cde] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Carlina Deflorin
- Rehabilitation Research Laboratory (2rLab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart/Manno, Switzerland
| | - Erich Hohenauer
- Rehabilitation Research Laboratory (2rLab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart/Manno, Switzerland.,School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom.,International University of Applied Sciences THIM, Landquart, Switzerland
| | - Rahel Stoop
- Rehabilitation Research Laboratory (2rLab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart/Manno, Switzerland
| | - Ulrike van Daele
- Department of Rehabilitation Sciences and Physiotherapy, University of Antwerp, Antwerp, Belgium.,Oscare, Organization for Burns, Scar After-Care and Research, Antwerp, Belgium
| | - Ron Clijsen
- Rehabilitation Research Laboratory (2rLab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart/Manno, Switzerland.,School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom.,International University of Applied Sciences THIM, Landquart, Switzerland.,Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Health, Bern University of Applied Sciences, Berne, Switzerland
| | - Jan Taeymans
- Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Health, Bern University of Applied Sciences, Berne, Switzerland
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McIntyre S, Nagi SS, McGlone F, Olausson H. The Effects of Ageing on Tactile Function in Humans. Neuroscience 2021; 464:53-58. [PMID: 33607227 DOI: 10.1016/j.neuroscience.2021.02.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 02/04/2021] [Accepted: 02/09/2021] [Indexed: 12/21/2022]
Abstract
Ageing is accompanied by a steady decline in touch sensitivity and acuity. Conversely, pleasant touch, such as experienced during a caress, is even more pleasant in old age. There are many physiological changes that might explain these perceptual changes, but researchers have not yet identified any specific mechanisms. Here, we review both the perceptual and structural changes to the touch system that are associated with ageing. The structural changes include reduced elasticity of the skin in older people, as well as reduced numbers and altered morphology of skin tactile receptors. Effects of ageing on the peripheral and central nervous systems include demyelination, which affects the timing of neural signals, as well as reduced numbers of peripheral nerve fibres. The ageing brain also undergoes complex changes in blood flow, metabolism, plasticity, neurotransmitter function, and, for touch, the body map in primary somatosensory cortex. Although several studies have attempted to find a direct link between perceptual and structural changes, this has proved surprisingly elusive. We also highlight the need for more evidence regarding age-related changes in peripheral nerve function in the hairy skin, as well as the social and emotional aspects of touch.
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Affiliation(s)
- Sarah McIntyre
- Center for Social and Affective Neuroscience, Linköping University, Sweden.
| | - Saad S Nagi
- Center for Social and Affective Neuroscience, Linköping University, Sweden
| | - Francis McGlone
- Research Centre in Brain & Behaviour, Liverpool John Moores University, Liverpool, United Kingdom
| | - Håkan Olausson
- Center for Social and Affective Neuroscience, Linköping University, Sweden
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Faraji Rad Z, Prewett PD, Davies GJ. High-resolution two-photon polymerization: the most versatile technique for the fabrication of microneedle arrays. MICROSYSTEMS & NANOENGINEERING 2021; 7:71. [PMID: 34567783 PMCID: PMC8433298 DOI: 10.1038/s41378-021-00298-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/01/2021] [Accepted: 07/16/2021] [Indexed: 05/05/2023]
Abstract
Microneedle patches have received much interest in the last two decades as drug/vaccine delivery or fluid sampling systems for diagnostic and monitoring purposes. Microneedles are manufactured using a variety of additive and subtractive micromanufacturing techniques. In the last decade, much attention has been paid to using additive manufacturing techniques in both research and industry, such as 3D printing, fused deposition modeling, inkjet printing, and two-photon polymerization (2PP), with 2PP being the most flexible method for the fabrication of microneedle arrays. 2PP is one of the most versatile and precise additive manufacturing processes, which enables the fabrication of arbitrary three-dimensional (3D) prototypes directly from computer-aided-design (CAD) models with a resolution down to 100 nm. Due to its unprecedented flexibility and high spatial resolution, the use of this technology has been widespread for the fabrication of bio-microdevices and bio-nanodevices such as microneedles and microfluidic devices. This is a pioneering transformative technology that facilitates the fabrication of complex miniaturized structures that cannot be fabricated with established multistep manufacturing methods such as injection molding, photolithography, and etching. Thus, microstructures are designed according to structural and fluid dynamics considerations rather than the manufacturing constraints imposed by methods such as machining or etching processes. This article presents the fundamentals of 2PP and the recent development of microneedle array fabrication through 2PP as a precise and unique method for the manufacture of microstructures, which may overcome the shortcomings of conventional manufacturing processes.
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Affiliation(s)
- Zahra Faraji Rad
- School of Mechanical and Electrical Engineering, University of Southern Queensland, Springfield Central, QLD 4300 Australia
| | - Philip D. Prewett
- Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT UK
- Oxacus Ltd, Dorchester-on-Thames, OX10 7HN UK
| | - Graham J. Davies
- Faculty of Engineering, UNSW Australia, Kensington, NSW 2052 Australia
- College of Engineering and Physical Sciences, School of Engineering, University of Birmingham, Birmingham, B15 2TT UK
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Zhou K, Feng K, Li C, Huang Z. A Weighted Average Phase Velocity Inversion Model for Depth-Resolved Elasticity Evaluation in Human Skin In-Vivo. IEEE Trans Biomed Eng 2020; 68:1969-1977. [PMID: 33326373 DOI: 10.1109/tbme.2020.3045133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE In current surface acoustic wave (SAW) elastography field, wavelength-depth inversion model is a straightforward and widely used inversion model for depth-resolved elasticity profile reconstruction. However, the elasticity directly evaluated from the wavelength-depth relationship is biased. Thus, a new inversion model, termed weighted average phase velocity (WAPV) inversion model, is proposed to provide depth-resolved Young's modulus estimate with better accuracy. METHODS The forward model for SAW phase velocity dispersion curve generation was derived from the numerical simulations of SAWs in layered materials, and inversion was implemented by matching the measured phase velocity dispersion curve to the one generated from the forward model using the least squares fitting. Three two-layer agar phantoms with different top-layer thicknesses and one three-layer agar phantom were tested to validate the proposed inversion model. Then the model was demonstrated on human skin at various sites (palm, forearm and back of hand) in-vivo. RESULTS In multi-layered agar phantoms, depth-resolved elasticity estimates provided by the model have a maximal total inversion error of 15.2% per sample after inversion error compensation. In in-vivo human skin, the quantified bulk Young's moduli (palm: 212 ± 78 kPa; forearm: 32 ± 11 kPa and back of hand: 29 ± 8 kPa) are comparable to the reference values in the literature. CONCLUSION The WAPV inversion model can provide accurate depth-resolved Young's modulus estimates in layered biological soft tissues. SIGNIFICANCE The proposed model can predict depth-resolved elasticity in layered biological soft tissues with a reasonable accuracy which traditional wavelength-depth inversion model cannot provide.
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Dolečková I, Čápová A, Machková L, Moravčíková S, Marešová M, Velebný V. Seasonal variations in the skin parameters of Caucasian women from Central Europe. Skin Res Technol 2020; 27:358-369. [PMID: 33084174 DOI: 10.1111/srt.12951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/07/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND The human skin is greatly affected by external factors such as UV radiation (UVR), ambient temperature (T), and air humidity. These factors oscillate during the year giving rise to the seasonal variations in the skin properties. The aim of this study was to evaluate the effect of seasons, environmental T, relative and absolute humidity on the skin parameters of Caucasian women, perform a literature review and discuss the possible factors lying behind the found changes. MATERIALS AND METHODS We measured stratum corneum (SC) hydration, transepidermal water loss (TEWL), sebum level, erythema index, and elasticity parameters R2 and R7 on the forehead and the cheek of Caucasian women from the Czech Republic throughout the year. We also performed a non-systematic literature review focused on the seasonal variations in these skin parameters. RESULTS We confirmed a well-documented low SC hydration and sebum production in winter. In spring, we found the lowest TEWL (on the forehead) and the highest SC hydration but also the highest erythema index and the lowest elasticity presumably indicating skin photodamage. For most of the skin parameters, the seasonal variations probably arise due to a complex action of different factors as we extensively discussed. CONCLUSION The data about the seasonal variations in the skin parameters are still highly inconsistent and further studies are needed for better understanding of the normal skin changes throughout the year.
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Dwivedi KK, Lakhani P, Kumar S, Kumar N. The Effect of Strain Rate on the Stress Relaxation of the Pig Dermis: A Hyper-Viscoelastic Approach. J Biomech Eng 2020; 142:091006. [PMID: 32005989 DOI: 10.1115/1.4046205] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Indexed: 01/01/2023]
Abstract
The understanding of strain rate-dependent mechanical properties of the skin is important for accurate prediction of its biomechanics under different loading conditions. This study investigated the effect of strain rate, i.e., 0.025/s (low), 0.5/s (medium), and 1.25/s (high), ranging in the physiological loading rate of connective tissue, on the stress-relaxation response of the porcine dermis. Results show that in the initial phase of the relaxation, the value of stress relaxation (extent of relaxation) was found higher for high strain rate. However, the equilibrium stress was found strain rate independent. A Mooney-Rivlin-based five-term quasi-linear viscoelastic (QLV) model was proposed to determine the effect of strain rate on the stress-relaxation behavior of the porcine dermis. The value of relaxation modulus G1 and G2 were found higher for the high strain rate, whereas the reverse trend was observed for G3, G4, and G5. Moreover, the value of time constants τ1,τ2,τ3τ4, and τ5 were found higher for low strain rate. Statistical analysis shows no significant difference in the values of G5, τ4, and τ5 among the three strain rates. The proposed model was found capable to fit the stress-relaxation response of skin with great accuracy, e.g., root-mean-squared-error (RMSE) value equal to 0.015 ± 0.00012 MPa. Moreover, this hyper-viscoelastic model can be utilized: to quantify the effects of age and diseases on the skin; to simulate the stresses on sutures during large wound closure and impact loading.
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Affiliation(s)
- Krashn K Dwivedi
- Centre for Biomedical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
| | - Piyush Lakhani
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
| | - Sachin Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
| | - Navin Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
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Dwivedi KK, Lakhani P, Kumar S, Kumar N. Frequency dependent inelastic response of collagen architecture of pig dermis under cyclic tensile loading: An experimental study. J Mech Behav Biomed Mater 2020; 112:104030. [PMID: 32858398 DOI: 10.1016/j.jmbbm.2020.104030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/06/2020] [Accepted: 08/07/2020] [Indexed: 01/20/2023]
Abstract
The evaluation of collagen architecture of the dermis in response to mechanical stimulation is important as it affects the macroscopic mechanical properties of the dermis. A detailed understanding of the processes involved in the alteration of the collagen structure is required to correlate the mechanical stimulation with tissue remodeling. This study investigated the effect of cyclic frequencies i.e. low (0.1 Hz), medium (2.0 Hz), and high (5.0 Hz) (physiological range) in the alteration of pig dermis collagen structure and its correlation with the macroscopic mechanical response of the dermis. The assessment of the collagen structure of virgin and mechanical tested specimens at tropocollagen, collagen fibril, and fiber level was performed using Fourier-transform infrared-attenuated total reflection (FTIR-ATR), atomic force microscopy (AFM), and scanning electron microscopy (SEM) respectively. After 103 cycles, a significantly higher alteration in collagen structure with discrete plastic-type damage was found for low frequency. This frequency dependent alteration of the collagen structure was found in correlation with the dermis macroscopic response. The value of inelastic strain, stress softening, damage parameter (reduction in elastic modulus), and reduction in energy dissipation were observed significantly large for slow frequency. A power-law based empirical relations, as a function of frequency and number of cycles, were proposed to predict the value of inelastic strain and damage parameter. This study also suggests that hierarchical structural response against the mechanical stimulation is time-dependent rather than cycle-dependent, may affect the tissue remodeling.
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Affiliation(s)
| | | | - Sachin Kumar
- Department of Mechanical Engineering, IIT, Ropar, India.
| | - Navin Kumar
- Center for Biomedical Engineering Department, IIT, Ropar, India; Department of Mechanical Engineering, IIT, Ropar, India.
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Kilo S, Wick J, Mini Vijayan S, Göen T, Horch RE, Ludolph I, Drexler H. Impact of physiologically relevant temperatures on dermal absorption of active substances - an ex-vivo study in human skin. Toxicol In Vitro 2020; 68:104954. [PMID: 32738276 DOI: 10.1016/j.tiv.2020.104954] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/08/2020] [Accepted: 07/27/2020] [Indexed: 11/18/2022]
Abstract
Skin temperature plays a certain role in the dermal absorption of substances, but the extent and mechanisms of skin temperatures-induced modulation in ranges caused by physiological thermoregulation or environmental conditions are largely unknown. The influence of dermal temperature on the absorption of the model lipophilic compound (anisole) and the model hydrophilic compounds (1,4-dioxane, ethanol) through human skin was investigated at three dermal temperatures (25, 32 and 39 °C) in an ex-vivo diffusion cell model. The substances were applied to the skin and transdermal penetration was monitored. All substances showed temperature dependent variations in their penetration behavior (3 h: 25-39 °C: 202-275% increase in cumulative, transdermally penetrated amounts). The relative differences in absorption in relation to temperature were greatest within 45 min after exposure (25-39 °C: 347-653% rise in cumulated penetration), although absolute amounts absorbed were small (45 min vs. 3 h: 4.5-14.5%). Regardless of blood circulation, skin temperature significantly influences the amount and kinetics of dermal absorption. Substance-dependent, temperature-related changes of the lipid layer order or the porous pathway may facilitate penetration. The early-stage modulation of transdermal penetration indicates transappendageal absorption, which may be relevant for short-term exposures. For both, toxicological evaluation and perfusion cell studies, it is important to consider the thermal influence on absorption or to perform the latter at a standardized temperature (32±1 °C).
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Affiliation(s)
- S Kilo
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany.
| | - J Wick
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - S Mini Vijayan
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - T Göen
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - R E Horch
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - I Ludolph
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - H Drexler
- Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
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Solé-Boldo L, Raddatz G, Schütz S, Mallm JP, Rippe K, Lonsdorf AS, Rodríguez-Paredes M, Lyko F. Single-cell transcriptomes of the human skin reveal age-related loss of fibroblast priming. Commun Biol 2020; 3:188. [PMID: 32327715 PMCID: PMC7181753 DOI: 10.1038/s42003-020-0922-4] [Citation(s) in RCA: 225] [Impact Index Per Article: 56.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 03/31/2020] [Indexed: 12/21/2022] Open
Abstract
Fibroblasts are an essential cell population for human skin architecture and function. While fibroblast heterogeneity is well established, this phenomenon has not been analyzed systematically yet. We have used single-cell RNA sequencing to analyze the transcriptomes of more than 5,000 fibroblasts from a sun-protected area in healthy human donors. Our results define four main subpopulations that can be spatially localized and show differential secretory, mesenchymal and pro-inflammatory functional annotations. Importantly, we found that this fibroblast 'priming' becomes reduced with age. We also show that aging causes a substantial reduction in the predicted interactions between dermal fibroblasts and other skin cells, including undifferentiated keratinocytes at the dermal-epidermal junction. Our work thus provides evidence for a functional specialization of human dermal fibroblasts and identifies the partial loss of cellular identity as an important age-related change in the human dermis. These findings have important implications for understanding human skin aging and its associated phenotypes.
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Affiliation(s)
- Llorenç Solé-Boldo
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120, Heidelberg, Germany
| | - Günter Raddatz
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120, Heidelberg, Germany
| | - Sabrina Schütz
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120, Heidelberg, Germany
| | - Jan-Philipp Mallm
- Division of Chromatin Networks, German Cancer Research Center and Bioquant, 69120, Heidelberg, Germany
| | - Karsten Rippe
- Division of Chromatin Networks, German Cancer Research Center and Bioquant, 69120, Heidelberg, Germany
| | - Anke S Lonsdorf
- Department of Dermatology, University Hospital, Ruprecht-Karls University of Heidelberg, 69120, Heidelberg, Germany
| | - Manuel Rodríguez-Paredes
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120, Heidelberg, Germany.
| | - Frank Lyko
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120, Heidelberg, Germany.
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Malo-Urriés M, Estébanez-de-Miguel E, Bueno-Gracia E, Tricás-Moreno JM, Santos-Lasaosa S, Hidalgo-García C. Sensory function in headache: a comparative study among patients with cluster headache, migraine, tension-type headache, and asymptomatic subjects. Neurol Sci 2020; 41:2801-2810. [DOI: 10.1007/s10072-020-04384-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/28/2020] [Indexed: 10/24/2022]
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Interpersonal differences in the friction response of skin relate to FTIR measures for skin lipids and hydration. Colloids Surf B Biointerfaces 2020; 189:110883. [PMID: 32105961 DOI: 10.1016/j.colsurfb.2020.110883] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 02/16/2020] [Accepted: 02/17/2020] [Indexed: 01/04/2023]
Abstract
Understanding the mechanical response of skin to contact is of importance when developing products that interact with the skin. The shear forces that arise due to friction in the interface are a key aspect of skin interactions, because shear is known to contribute to discomfort and tissue injury. However, the frictional response of skin shows large variations between people. It has been hypothesised that these variations relate to differences between people in the physiological properties of their skin, but the underlying mechanisms are not well understood. In order to gain new insights into these interpersonal differences in friction behaviour, in vivo FTIR measurements and in vivo friction measurements were performed on the same patch of skin. Quantitative analysis of the various peaks in the FTIR spectra provided information on the moisture content of the stratum corneum and the amount and mechanical properties of the lipids on the skin. The lipid viscosity, as characterised by the width of the 2920 cm-1 peak, correlates with the friction, whilst, interestingly, no relationship was found between the quantity of lipids on the skin surface and the coefficient of friction. Additionally, and as expected, a fairly strong correlation was obtained between the moisture content, as characterised by the height of the Amide I peak and the coefficient of friction. The presented results show that spectroscopy techniques can be used in as a non-invasive method to identify people who may show elevated levels of friction and thus are at increased risk of developing shear induced tissue injury.
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Meador WD, Sugerman GP, Story HM, Seifert AW, Bersi MR, Tepole AB, Rausch MK. The regional-dependent biaxial behavior of young and aged mouse skin: A detailed histomechanical characterization, residual strain analysis, and constitutive model. Acta Biomater 2020; 101:403-413. [PMID: 31614209 DOI: 10.1016/j.actbio.2019.10.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 01/12/2023]
Abstract
Skin fulfills several vital functions, many of which are dependent on its mechanical properties. Therefore, as mice have become an invaluable model for skin research, determining murine skin's mechanical properties is important. Specifically, skin's mechanical properties are important for functional tests as well as for prognostic and diagnostic purposes. Additionally, computational simulations of skin behavior are becoming commonplace, rendering accurate models of murine skin's constitutive behavior necessary. To date, our knowledge of mouse skin mechanics shows significant gaps. For example, there are no comprehensive reports correlating skin's mechanical properties with region, age, and direction. Moreover, mouse skin's residual strain behavior has not been reported on. In our current work, we set out to fill these gaps. Based on histology, 2-photon microscopy, and planar biaxial testing, while accurately tracking various reference configurations, we report on differences in gross structure, microstructural organization, and constitutive response of skin, and cast those properties into a versatile Fung-type hyperelastic constitutive law for three reference configurations. Our data is the most comprehensive report contrasting the mechanical properties of young (12 weeks) and aged (52 weeks) mouse skin and will, thus, be valuable to basic science as control data, and provide accurate constitutive laws for mouse skin modeling. STATEMENT OF SIGNIFICANCE: Our findings are significant as they fill several gaps in our understanding of mouse skin mechanics. This is particularly important as mouse skin is becoming a frequent and critical model of human skin for cosmetic and medical science. Specifically, we quantified how mechanical properties of mice skin vary with age, with location, and with direction. Additionally, we cast our findings into constitutive models that can be used by others for predictive computer simulations of skin behavior.
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Sakai S, Inoue-Sato M, Amemiya R, Murakami M, Inagaki K, Sakairi Y. The influence of autogenic training on the physical properties of skin and cardiac autonomic activity in postmenopausal women: an exploratory study. Int J Dermatol 2020; 59:103-109. [PMID: 31294461 DOI: 10.1111/ijd.14582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/08/2019] [Accepted: 06/14/2019] [Indexed: 01/24/2023]
Abstract
BACKGROUND Autogenic training (AT) is a major relaxation training technique whose clinical efficacy has been verified in dermatology. Many reports demonstrate ameliorated skin conditions in AT-treated subjects with reduced psychological stress. However, no studies have examined the effects of AT on the skin of postmenopausal women. OBJECTIVES We examine the influences of AT on the physical properties of skin and cardiac autonomic activity in postmenopausal women. METHODS Postmenopausal women were classed into an AT group and a control one. The women in the AT group were mentored by a professional to practice AT twice a day for 7 weeks. The women in the control group were instructed to close their eyes for 3 minutes instead of AT. Hydration of the stratum corneum (SC), transepidermal water loss (TEWL), skin elasticity and heart-rate variability (HRV) were measured before and after the study period to examine how they changed. RESULTS SC hydration and skin elasticity of the cheek, increased in both groups, and the increase was significantly higher in the AT group (n = 14) than in the control group (n = 12) (P < 0.05, Cohen's d = 1.03; P < 0.05, Cohen's d = 0.99; respectively). TEWL did not change in either group. LF/HF was lower in the AT group than in the control group (P < 0.05, Cohen's d = 0.91). CONCLUSION AT increased SC hydration and skin elasticity with changes in the balance of autonomic nervous system activity in postmenopausal women, implying that AT may have improvement effects on aged skin by menopause.
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Affiliation(s)
- Shingo Sakai
- Skincare Products Research, Kao Corporation, Odawara, Kanagawa, Japan
| | - Mayumi Inoue-Sato
- Skincare Products Research, Kao Corporation, Odawara, Kanagawa, Japan
| | - Rei Amemiya
- Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Motoko Murakami
- Skincare Products Research, Kao Corporation, Odawara, Kanagawa, Japan
| | - Kazuki Inagaki
- Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yosuke Sakairi
- Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
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Thieulin C, Pailler-Mattei C, Abdouni A, Djaghloul M, Zahouani H. Mechanical and topographical anisotropy for human skin: Ageing effect. J Mech Behav Biomed Mater 2019; 103:103551. [PMID: 32090946 DOI: 10.1016/j.jmbbm.2019.103551] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 10/30/2019] [Accepted: 11/20/2019] [Indexed: 11/25/2022]
Abstract
Skin ageing is a complex process which strongly impacts the three skin layers (epidermis, dermis, hypodermis) both functionally and structurally. Of particular interest are the effects of ageing on the dermis biomechanics and how this evolution can impact the reorganization of the cutaneous lines which compose the skin relief. It has been argued that the skin relief could reflect the underlying mechanical condition of the skin. Nevertheless, there is not yet conclusive evidence of the existence of such a link. This work aims at experimentally studying, in vivo, the correlation between the anisotropy of human skin biomechanics and skin topography as a function of ageing. The study was conducted on a panel of 20 men divided into 4 groups according to age (from 23 to 64 years old). The measurements were performed on the right volar forearm of each volunteer. For the biomechanical measurements, an innovative contactless bio-rheometer was developed. It allows access to the mechanical behaviour of the skin in several directions. This device generates an air blast without any contact with the skin area and measures its dynamic response (evaluation of speed of wave propagation) with a linear laser. Moreover, a turntable enables measurements to be made in different angular directions. To analyse the topography of skin relief, we proposed a new method, based on watershed and linear radon transformations. First, an optical analysis of a replica of the skin relief is performed. Then, from the skin image obtained, the density of the cutaneous lines is calculated in different directions using watersheld transformation. The orientation of the detected lines is then estimated with an algorithm based on linear radon transformation. The results observed show a good correlation between the skin relief and the mechanical properties of the skin all along the ageing process. For both topography and mechanical properties, there is a transition from an almost isotropic mechanical behaviour to an anisotropic one as a function of ageing process. Thus, we might conclude that the skin relief reflects the underlying mechanical conditions of the skin.
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Affiliation(s)
- C Thieulin
- Laboratoire de Tribologie et Dynamique des Systèmes, UMR-CNRS 5513, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, Ecully, France.
| | - C Pailler-Mattei
- Laboratoire de Tribologie et Dynamique des Systèmes, UMR-CNRS 5513, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, Ecully, France; Université de Lyon, Faculté de Pharmacie-ISPB, Laboratoire de Biophysique, Lyon, France
| | - A Abdouni
- Laboratoire de Tribologie et Dynamique des Systèmes, UMR-CNRS 5513, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, Ecully, France
| | - M Djaghloul
- Laboratoire de Tribologie et Dynamique des Systèmes, UMR-CNRS 5513, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, Ecully, France
| | - H Zahouani
- Laboratoire de Tribologie et Dynamique des Systèmes, UMR-CNRS 5513, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, Ecully, France
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Rodriguez E, Chong BF. SnapshotDx Quiz: October 2019. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Hurley S, Messaraa C, O'Connor C, Metois A, Walsh M, Mc Namee D, Mansfield A, Robertson N, Doyle L, Mavon A. DermaTOP Blue and Antera 3D as methods to assess cosmetic solutions targeting eyelid sagging. Skin Res Technol 2019; 26:209-214. [PMID: 31560408 DOI: 10.1111/srt.12781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/02/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND As the eye contour ages, the skin on the lid becomes lax often causing a voluminous protrusion where the superior palpebral sulcus begins to sag onto the upper eyelid. This sagging feature may present a novel anti-ageing target for cosmetic products when treating the eye area. A quantitative method to evaluate the volume of this sagging feature has not been previously established. We investigate the use of the DermaTOP fringe projector and Antera 3D Camera to this end. METHODS Eyelid topographic measurements were collected on 20 female volunteers aged 50-75 years with the DermaTOP and Antera 3D. The DermaTOP and Antera 3D measurements were assessed for reproducibility and product effect detection capabilities. RESULTS The DermaTOP and Antera 3D successfully measured sagging feature volume, demonstrated reproducibility of measurement and furthermore were suitably sensitive to allow for detection of sagging feature volume reduction after a single application of aqueous tightening serum. DermaTOP parameters were found to moderately correlated with the Antera 3D parameters. CONCLUSION Both the DermaTOP and Antera 3D allow for quantitative measurement of eyelid sagging feature volume and in-turn permit evaluation of anti-ageing cosmetic preparations targeting the eyelid.
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Affiliation(s)
- Sarah Hurley
- Oriflame Research and Development, R&D, Bray, Ireland
| | | | | | | | - Melissa Walsh
- Oriflame Research and Development, R&D, Bray, Ireland
| | | | | | | | - Leah Doyle
- Oriflame Research and Development, R&D, Bray, Ireland
| | - Alain Mavon
- Oriflame Skin Research Institute, Oriflame Cosmetics AB, Stockholm, Sweden
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