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Egawa T, Ogawa T, Yokokawa T, Kido K, Iyama R, Zhao H, Kurogi E, Goto K, Hayashi T. Glycative stress inhibits hypertrophy and impairs cell membrane integrity in overloaded mouse skeletal muscle. J Cachexia Sarcopenia Muscle 2024; 15:883-896. [PMID: 38575520 PMCID: PMC11154761 DOI: 10.1002/jcsm.13444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 01/04/2024] [Accepted: 01/21/2024] [Indexed: 04/06/2024] Open
Abstract
BACKGROUND Glycative stress, characterized by the formation and accumulation of advanced glycation end products (AGEs) associated with protein glycation reactions, has been implicated in inducing a decline of muscle function. Although the inverse correlation between glycative stress and muscle mass and strength has been demonstrated, the underlying molecular mechanisms are not fully understood. This study aimed to elucidate how glycative stress affects the skeletal muscle, particularly the adaptive muscle response to hypertrophic stimuli and its molecular mechanism. METHODS Male C57BL/6NCr mice were randomly divided into the following two groups: the bovine serum albumin (BSA)-treated and AGE-treated groups. Mice in the AGE-treated group were intraperitoneally administered AGEs (0.5 mg/g) once daily, whereas those in the BSA-treated group received an equal amount of BSA (0.5 mg/g) as the vehicle control. After 7 days of continuous administration, the right leg plantaris muscle of mice in each group underwent functional overload treatment by synergist ablation for 7 days to induce muscle hypertrophy. In in vitro studies, cultured C2C12 myocytes were treated with AGEs (1 mg/mL) to examine cell adhesion and cell membrane permeability. RESULTS Continuous AGE administration increased the levels of fluorescent AGEs, Nε-(carboxymethyl) lysine, and methylglyoxal-derived hydroimidazolone-1 in both plasma and skeletal muscle. Plantaris muscle weight, muscle fibre cross-sectional area, protein synthesis rate, and the number of myonuclei increased with functional overload in both groups; however, the increase was significantly reduced by AGE treatment. Some muscles of AGE-treated mice were destroyed by functional overload. Proteomic analysis was performed to explore the mechanisms of muscle hypertrophy suppression and myofibre destruction by AGEs. When principal component analysis was performed on 4659 data obtained by proteomic analysis, AGE treatment was observed to affect protein expression only in functionally overloaded muscles. Enrichment analysis of the 436 proteins extracted using the K-means method further identified a group of proteins involved in cell adhesion. Consistent with this finding, dystrophin-glycoprotein complex proteins and cell adhesion-related proteins were confirmed to increase with functional overload; however, this was attenuated by AGE treatment. Additionally, the treatment of C2C12 muscle cells with AGEs inhibited their ability to adhere and increased cell membrane permeability. CONCLUSIONS This study indicates that glycative stress may be a novel pathogenic factor in skeletal muscle dysfunctions by causing loss of membrane integrity and preventing muscle mass gain.
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Affiliation(s)
- Tatsuro Egawa
- Laboratory of Health and Exercise Sciences, Graduate School of Human and Environmental StudiesKyoto UniversityKyotoJapan
| | - Takeshi Ogawa
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental StudiesKyoto UniversityKyotoJapan
| | - Takumi Yokokawa
- Division of Food Science and Biotechnology, Graduate School of AgricultureKyoto UniversityKyotoJapan
| | - Kohei Kido
- Health and Medical Research InstituteNational Institute of Advanced Industrial Science and Technology (AIST)KagawaJapan
- Institute for Physical ActivityFukuoka UniversityFukuokaJapan
| | - Ryota Iyama
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental StudiesKyoto UniversityKyotoJapan
| | - Haiyu Zhao
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental StudiesKyoto UniversityKyotoJapan
| | - Eriko Kurogi
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental StudiesKyoto UniversityKyotoJapan
| | - Katsumasa Goto
- Laboratory of Physiology, Graduate School of Health SciencesToyohashi SOZO UniversityToyohashiJapan
| | - Tatsuya Hayashi
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental StudiesKyoto UniversityKyotoJapan
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Portoghese C, Deppisch M, Sonenblum S, Samson B, Munro C, Capasso V, Call E, Black J, Brienza D. The Role of Shear Stress and Shear Strain in Pressure Injury Development. Adv Skin Wound Care 2024; 37:20-25. [PMID: 38117167 DOI: 10.1097/asw.0000000000000075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
ABSTRACT Although other patient safety indicators have seen a decline, pressure injury (PI) incidence has continued to rise. In this article, the authors discuss the role of shear stress and shear strain in PI development and describe how accurate assessment and management can reduce PI risk. They provide explanations of shear stress, shear strain, friction, and tissue deformation to support a better clinical understanding of how damaging these forces are for soft tissue. Clinicians must carefully assess each patient's risk factors regarding shear forces within the contexts of activity and mobility. The authors also provide a toolbox of mitigation strategies, including support surface selection, selection of materials that contact the individual, management of immobility using positioning techniques, and the use of safe patient handling techniques. With a clear understanding of how shear forces affect PI risk and mitigation strategies, clinicians will more accurately assess PI risk and improve PI prevention care plans, ultimately reducing PI incidence to become more aligned with other patient safety indicators.
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Affiliation(s)
- Caroline Portoghese
- Caroline Portoghese, OTR/L, ATP/SMS, is Assistive Technology Professional and Rehabilitation Consultant, Handi Medical, Saint Paul, Minnesota. Michelle Deppisch, PT, CWS, is Wound Care Consultant, Michele Deppisch PT, CWS, LLC, Hertford, North Carolina. Sharon Sonenblum, PhD, is Principal Research Scientist, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia. Barbara Samson, OTR/L, MBA, CWS, CSPHC, is Executive Clinical Specialist, Mölnlycke Health Care, Peachtree Corners, Georgia. Cassendra Munro, PhD, RN, RNFA, CNOR, Nurse Scientist, Stanford Health Care, Office of Research, Patient Care Services, Menlo Park, California. Virginia Capasso, PhD, ANP-BC, ACNS-BC, CWS, is Advanced Practice Nurse and Nurse Scientist, Massachusetts General Hospital, Boston, Massachusetts, and Instructor in Surgery, Harvard Medical School, Boston. Evan Call, MS, CSM-NRM, is Adjunct Faculty, Weber State University, Ogden, Utah. Joyce Black, PhD, RN, FAAN, is Florence Neidfelt Professor of Nursing, University of Nebraska Medical Center, College of Nursing, Omaha, Nebraska. David Brienza, PhD, is Professor, University of Pittsburgh, Pittsburgh, Pennsylvania. The authors have disclosed no financial relationships related to this article. Submitted March 12, 2023; accepted in revised form July 5, 2023
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Samadian A, Kratochvílová M, Hokynková A, Šín P, Nováková M, Štěpka P, Pokorná A, Babula P. Changes in gene expression in pressure ulcers debrided by different approaches - a pilot study. Physiol Res 2023; 72:S535-S542. [PMID: 38165757 PMCID: PMC10861252 DOI: 10.33549/physiolres.935222] [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: 03/31/2023] [Accepted: 09/11/2023] [Indexed: 02/01/2024] Open
Abstract
Pressure ulcers (PUs), also known as pressure injuries, are chronic wounds that represent potential lifelong complications. Pressure ulcers of a deep category (III and IV) are often indicated for surgical treatment - debridement and surgical reconstruction. Sharp surgical debridement is widely used in the debridement of PUs; however, the Versajet® hydrosurgery system is becoming an increasingly popular tool for tangential excision in surgery due to its numerous advantages. This work focused on the expression of selected genes, especially those associated with oxidative stress, in PUs debrided by two approaches - sharp surgical debridement and debridement using Versajet® hydrosurgery system. Expression of following genes was evaluated: NFE2L2, ACTA2, NFKB1, VEGFA, MKI67, HMOX1, HMOX2, HIF1A, and SOD2. ACTB and PSMB were used as housekeeping genes. So far, five patients have been enrolled in the study. Preliminary results suggest no significant difference in gene expression with different pressure ulcer treatment approaches except NFE2L2, despite the macroscopic differences. However, the results revealed correlations between the expression of some genes, namely HIF1A and SOD2, VEGFA and SOD2 and VEGFA and HIF1A. These results may indicate a connection between hypoxia, oxidative stress, pressure ulcer healing processes and angiogenesis.
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Affiliation(s)
- A Samadian
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic, Department of Burns and Plastic Surgery, University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
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Yoshimura M, Kohno M, Okamoto Y, Tsuchiya S, Ogawa K, Fukuma A, Kurihara C, Miyama M, Matsumura H. The incidence of intraoperatively acquired pressure injuries in the park-bench position was reduced by applying soft silicone multilayer foam dressings. Int Wound J 2023; 21:e14407. [PMID: 37814469 PMCID: PMC10824620 DOI: 10.1111/iwj.14407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/07/2023] [Accepted: 09/07/2023] [Indexed: 10/11/2023] Open
Abstract
The Park-Bench Position (PBP) is associated with a high incidence rate of intraoperatively acquired pressure injuries (IAPIs). Preventive measures must be established to prevent the development of IAPIs. We investigated the risk factors for PBP by applying a soft silicone multilayered foam dressing (SMD) under core temperature management to prevent IAPIs. We conducted a prospective, single-centre, open-label observational study of patients undergoing elective neurosurgery operations using PBP in a university hospital in Japan. The incidence rate of IAPIs in this study was compared with that in our two previous studies, in which a film dressing was applied and core temperature management was not performed. IAPIs developed in 90 patients (6.7%); in the lateral thoracic region in five patients and the iliac crest region in one patient. The operative time (every 1 h: p = 0.0001, OR: odds ratio 3.62, 95% CI: confidence interval 1.73-11.42) was significantly associated with the incidence of IAPIs. In our two previous studies, the incidence rate of IAPIs was 11.0% and 24.1%, respectively, when film dressing was used. SMD may weaken the involvement of risk factors in IAPIs.
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Affiliation(s)
- Mine Yoshimura
- Department of NursingTokyo Medical University HospitalTokyoJapan
| | - Michihiro Kohno
- Department of NeurosurgeryTokyo Medical UniversityTokyoJapan
| | - Yukako Okamoto
- Department of NursingTokyo Medical University HospitalTokyoJapan
| | - Sakura Tsuchiya
- Department of NursingTokyo Medical University HospitalTokyoJapan
| | - Kyoko Ogawa
- Department of NursingTokyo Medical University HospitalTokyoJapan
| | - Akane Fukuma
- Department of NursingTokyo Medical University HospitalTokyoJapan
| | - Chie Kurihara
- Department of NursingTokyo Medical University HospitalTokyoJapan
| | - Mari Miyama
- Department of NursingTokyo Medical University HospitalTokyoJapan
| | - Hajime Matsumura
- Department of Plastic and Reconstructive SurgeryTokyo Medical UniversityTokyoJapan
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Jia J, Chong S, Yu L, Yao Y. Cell membrane tensile strain under cyclic compression: A viscoelastic myoblast finite element model. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2022. [DOI: 10.1016/j.medntd.2022.100155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Gefen A. The influence zone: a critical performance measure for negative pressure wound therapy systems. BRITISH JOURNAL OF NURSING (MARK ALLEN PUBLISHING) 2022; 31:S8-S12. [PMID: 35980923 DOI: 10.12968/bjon.2022.31.15.s8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This article provides an introduction to the theory of, what is termed, the 'influence zone' in the context of negative pressure wound therapy (NPWT). It is a quantitative bioengineering performance measure for NPWT systems, to indicate their effectiveness, namely, how far from the wound bed edges a specific system is able to deliver effective mechano-stimulation into the periwound, and at which intensity. The influence zone therefore provides objective and standardised metrics of one of the fundamental modes of action of NPWT systems: the ability to effectively and optimally deform both the wound and periwound macroscopically and microscopically. Most important is the mechanical deformation of the periwound area to activate cells responsible for tissue repair, particularly (myo)fibroblasts. Notably, the influence zone must extend sufficiently into the periwound to stimulate (myo)fibroblasts in order that they migrate and progress the wound healing process, facilitating the formation of scar tissue, without overstretching the periwound tissues so as not cause or escalate further cell and tissue damage. The inclusion of the influence zone theory within research to investigate the efficacy of NPWT systems facilitates systematic comparisons of commercially available and potentially new systems. This approach has the capacity to guide not only research and development work, but also clinical decision-making. Recently published research found that inducing an effective influence zone first and foremost requires continuous delivery of the intended pressure to the wound bed.
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Affiliation(s)
- Amit Gefen
- Professor of Biomedical Engineering, The Herbert J Berman Chair in Vascular Bioengineering, Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Israel
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In silico stress fibre content affects peak strain in cytoplasm and nucleus but not in the membrane for uniaxial substrate stretch. Med Biol Eng Comput 2021; 59:1933-1944. [PMID: 34392447 DOI: 10.1007/s11517-021-02393-z] [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: 09/03/2020] [Accepted: 06/13/2021] [Indexed: 10/20/2022]
Abstract
Existing in silico models for single cell mechanics feature limited representations of cytoskeletal structures that contribute substantially to the mechanics of a cell. We propose a micromechanical hierarchical approach to capture the mechanical contribution of actin stress fibres. For a cell-specific fibroblast geometry with membrane, cytoplasm and nucleus, the Mori-Tanaka homogenization method was employed to describe cytoplasmic inhomogeneities and constitutive contribution of actin stress fibres. The homogenization was implemented in a finite element model of the fibroblast attached to a substrate through focal adhesions. Strain in cell membrane, cytoplasm and nucleus due to uniaxial substrate stretch was assessed for different stress fibre volume fractions and different elastic modulus of the substrate. A considerable decrease of the peak strain with increasing stress fibre content was observed in cytoplasm and nucleus but not the membrane, whereas the peak strain in cytoplasm, nucleus and membrane increased for increasing elastic modulus of the substrate. Finite element mesh of reconstructed human fibroblast and intracellular strain distribution in cell subjected to substrate stretch.
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Gefen A, Brienza DM, Cuddigan J, Haesler E, Kottner J. Our contemporary understanding of the aetiology of pressure ulcers/pressure injuries. Int Wound J 2021; 19:692-704. [PMID: 34382331 PMCID: PMC8874092 DOI: 10.1111/iwj.13667] [Citation(s) in RCA: 82] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/02/2021] [Accepted: 07/25/2021] [Indexed: 12/25/2022] Open
Abstract
In 2019, the third and updated edition of the Clinical Practice Guideline (CPG) on Prevention and Treatment of Pressure Ulcers/Injuries has been published. In addition to this most up‐to‐date evidence‐based guidance for clinicians, related topics such as pressure ulcers (PUs)/pressure injuries (PIs) aetiology, classification, and future research needs were considered by the teams of experts. To elaborate on these topics, this is the third paper of a series of the CPG articles, which summarises the latest understanding of the aetiology of PUs/PIs with a special focus on the effects of soft tissue deformation. Sustained deformations of soft tissues cause initial cell death and tissue damage that ultimately may result in the formation of PUs/PIs. High tissue deformations result in cell damage on a microscopic level within just a few minutes, although it may take hours of sustained loading for the damage to become clinically visible. Superficial skin damage seems to be primarily caused by excessive shear strain/stress exposures, deeper PUs/PIs predominantly result from high pressures in combination with shear at the surface over bony prominences, or under stiff medical devices. Therefore, primary PU/PI prevention should aim for minimising deformations by either reducing the peak strain/stress values in tissues or decreasing the exposure time.
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Affiliation(s)
- Amit Gefen
- The Herbert J. Berman Chair in Vascular Bioengineering, Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - David M Brienza
- Departments of Rehabilitation Science and Technology & Bioengineering and the McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Janet Cuddigan
- College of Nursing, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Emily Haesler
- School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Australia.,Australian Centre for Evidence Based Aged Care, School of Nursing and Midwifery, LaTrobe University, Melbourne, Victoria, Australia.,Australian National University Medical School, Academic Unit of General Practice, Australian National University, Canberra, ACT, Australia
| | - Jan Kottner
- Charité Center 1 for Health and Human Sciences, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Abstract
GENERAL PURPOSE To outline a conceptual schema describing the relationships among the empirically supported risk factors, the etiologic factors, and the mitigating measures that influence pressure injury (PI) development in the critical care population. TARGET AUDIENCE This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. LEARNING OBJECTIVES/OUTCOMES After participating in this educational activity, the participant will: 1. Choose a static intrinsic factor that increases the risk for the development of PI. 2. List several dynamic intrinsic risk factors for developing a PI. 3. Identify dynamic extrinsic risk factors that may predispose a patient to developing a PI. 4. Explain the pathophysiology of PI development.
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The mechanobiology theory of the development of medical device-related pressure ulcers revealed through a cell-scale computational modeling framework. Biomech Model Mechanobiol 2021; 20:851-860. [PMID: 33606118 PMCID: PMC7893381 DOI: 10.1007/s10237-021-01432-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/03/2021] [Indexed: 12/17/2022]
Abstract
Pressure ulcers are localized sites of tissue damage which form due to the continuous exposure of skin and underlying soft tissues to sustained mechanical loading, by bodyweight forces or because a body site is in prolonged contact with an interfacing object. The latter is the common cause for the specific sub-class of pressure ulcers termed ‘medical device-related pressure ulcers’, where the injury is known to have been caused by a medical device applied for a diagnostic or therapeutic purpose. Etiological research has established three key contributors to pressure ulcer formation, namely direct cell and tissue deformation, inflammatory edema and ischemic damage which are typically activated sequentially to fuel the injury spiral. Here, we visualize and analyze the above etiological mechanism using a new cell-scale modeling framework. Specifically, we consider here the deformation-inflicted and inflammatory contributors to the damage progression in a medical device-related pressure ulcer scenario, forming under a continuous positive airway pressure ventilation mask at the microarchitecture of the nasal bridge. We demonstrate the detrimental effects of exposure to high-level continuous external strains, which causes deformation-inflicted cell damage almost immediately. This in turn induces localized edema, which exacerbates the cell-scale mechanical loading state and thereby progresses cell damage further in a nonlinear, escalating pattern. The cell-scale quantitative description of the damage cascade provided here is important not only from a basic science perspective, but also for creating awareness among clinicians as well as industry and regulators with regards to the need for improving the design of skin-contacting medical devices.
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Mansur R, Peko L, Shabshin N, Cherbinski L, Neeman Z, Gefen A. Ultrasound elastography reveals the relation between body posture and soft-tissue stiffness which is relevant to the etiology of sitting-acquired pressure ulcers. Physiol Meas 2021; 41:124002. [PMID: 33126232 DOI: 10.1088/1361-6579/abc66d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Sitting-acquired pressure ulcers (PUs) are common in wheelchair users. These PUs are often serious and may involve deep tissue injury (DTI). Investigating the mechanical properties of the tissues susceptible to DTI may help in guiding the prevention and early detection of PUs. In this study, shear wave elastography (SWE) was used to measure the normative mechanical properties of the soft tissues of the buttocks, i.e. skeletal muscle and subcutaneous fat, under the ischial tuberosities, in a convenient sample of healthy adults without weight bearing and with weight bearing of different times. APPROACH We compared the stiffness properties of these soft tissues between the lying prone and sitting postures, to determine whether there are detectable property changes that may be associated with the type of posture. We hypothesized that muscle contractions and 3D tissue configurations associated with the posture may influence the measured tissue stiffnesses. MAIN RESULTS Our results have shown that indeed, SWE values differed significantly across postures, but not over time in a specific posture or for the right versus left sides of the body. SIGNIFICANCE We have therefore demonstrated that soft-tissue stiffness increases when sitting with weight bearing and may contribute to increasing the potential PU risk in sitting compared to lying prone, given the stiffer behavior of tissues observed in sitting postures.
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Affiliation(s)
- Ruba Mansur
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
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Role of microRNAs in Pressure Ulcer Immune Response, Pathogenesis, and Treatment. Int J Mol Sci 2020; 22:ijms22010064. [PMID: 33374656 PMCID: PMC7793489 DOI: 10.3390/ijms22010064] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/16/2020] [Accepted: 12/22/2020] [Indexed: 02/07/2023] Open
Abstract
Pressure ulcers are preventable, yet highly prevalent, chronic wounds that have significant patient morbidity and high healthcare costs. Like other chronic wounds, they are characterized by impaired wound healing due to dysregulated immune processes. This review will highlight key biochemical pathways in the pathogenesis of pressure injury and how this signaling leads to impaired wound healing. This review is the first to comprehensively describe the current literature on microRNA (miRNA, miR) regulation of pressure ulcer pathophysiology.
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Katzengold R, Orlov A, Gefen A. A novel system for dynamic stretching of cell cultures reveals the mechanobiology for delivering better negative pressure wound therapy. Biomech Model Mechanobiol 2020; 20:193-204. [PMID: 32803464 DOI: 10.1007/s10237-020-01377-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 08/05/2020] [Indexed: 12/20/2022]
Abstract
Serious wounds, both chronic and acute (e.g., surgical), are among the most common, expensive and difficult-to-treat health problems. Negative pressure wound therapy (NPWT) is considered a mainstream procedure for treating both wound types. Soft tissue deformation stimuli are the crux of NPWT, enhancing cell proliferation and migration from peri-wound tissues which contributes to healing. We developed a dynamic stretching device (DSD) contained in a miniature incubator for applying controlled deformations to fibroblast wound assays. Prior to the stretching experiments, fibroblasts were seeded in 6-well culture plates with elastic substrata and let to reach confluency. Squashing damage was then induced at the culture centers, and the DSD was activated to deliver stretching regimes that represented common clinical NPWT protocols at two peak strain levels, 0.5% and 3%. Analyses of the normalized maximal migration rate (MMR) data for the collective cell movement revealed that for the 3% strain level, the normalized MMR of cultures subjected to a 0.1 Hz stretch frequency regime was ~ 1.4 times and statistically significantly greater (p < 0.05) than that of the cultures subjected to no-stretch (control) or to static stretch (2nd control). Correspondingly, analysis of the time to gap closure data indicated that the closure time of the wound assays subjected to the 0.1 Hz regime was ~ 30% shorter than that of the cultures subjected to the control regimes (p < 0.05). Other simulated NPWT protocols did not emerge as superior to the controls. The present method and system are a powerful platform for further revealing the mechanobiology of NPWT and for improving this technology.
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Affiliation(s)
- Rona Katzengold
- The Herbert J. Berman Chair in Vascular Bioengineering, Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Alexey Orlov
- The Herbert J. Berman Chair in Vascular Bioengineering, Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Amit Gefen
- The Herbert J. Berman Chair in Vascular Bioengineering, Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 6997801, Tel Aviv, Israel.
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Wang Y, Song J, Liu X, Liu J, Zhang Q, Yan X, Yuan X, Ren D. Multiple Effects of Mechanical Stretch on Myogenic Progenitor Cells. Stem Cells Dev 2020; 29:336-352. [PMID: 31950873 DOI: 10.1089/scd.2019.0286] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Yaqi Wang
- Department of Stomatology Medical Center, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
- Department of Stomatology, Medical School of Qingdao University, Qingdao, China
| | - Jing Song
- Department of Stomatology Medical Center, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
- Department of Stomatology, Medical School of Qingdao University, Qingdao, China
| | - Xinqiang Liu
- Department of Stomatology Medical Center, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Jun Liu
- Department of Stomatology Medical Center, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Qiang Zhang
- Department of Stomatology Medical Center, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
- Department of Stomatology, Medical School of Qingdao University, Qingdao, China
| | - Xiao Yan
- Department of Stomatology Medical Center, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
- Department of Stomatology, Medical School of Qingdao University, Qingdao, China
| | - Xiao Yuan
- Department of Stomatology Medical Center, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Dapeng Ren
- Department of Stomatology Medical Center, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
- Department of Stomatology, Medical School of Qingdao University, Qingdao, China
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Yoshimura M, Ohura N, Santamaria N, Watanabe Y, Akizuki T, Gefen A. High body mass index is a strong predictor of intraoperative acquired pressure injury in spinal surgery patients when prophylactic film dressings are applied: A retrospective analysis prior to the BOSS Trial. Int Wound J 2020; 17:660-669. [PMID: 32067390 DOI: 10.1111/iwj.13287] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 12/04/2019] [Accepted: 12/05/2019] [Indexed: 12/12/2022] Open
Abstract
We reported the efficacy of soft silicone multilayered foam dressings in preventing intraoperatively acquired pressure injuries (IAPIs) in the prone position using a Relton-Hall frame (BOSS trial). The aim of this study was to clarify the incidence and extract the risk factors for IAPIs in cases in which polyurethane film dressing was used against IAPIs before the BOSS trial period. This study conducted as a retrospective dual-center cohort study between August 2014 and Jun 2015 using the medical records in the operating room. The incidence of IAPIs that developed within 24 hours after surgery was 7.1% (7/99). The multivariate logistic regression analysis revealed that body mass index (BMI) (P = .0016, odds ratio [OR]: 1.22, 95% confidence interval (CI) 1.08-1.4) and length of surgery (P < .0001, OR 2.47, 95% CI 1.86-3.51) were independently associated with the development of IAPIs. Since high BMI was not extracted in BOSS trial, we conclude that the application of soft silicone multilayer foam dressings is important for preventing the development of IAPIs in patients with high BMI values.
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Affiliation(s)
- Mine Yoshimura
- Department of Nursing, Tokyo Medical University Hospital, Tokyo, Japan
| | - Norihiko Ohura
- Department of Plastic and Reconstructive Surgery, Kyorin University School of Medicine, Tokyo, Japan
| | - Nick Santamaria
- Department of Nursing, Faculty of Medicine Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Yorikatsu Watanabe
- Department of Plastic, Reconstructive & Aesthetic Surgery, Tokyo Metropolitan Police Hospital, Tokyo, Japan
| | - Tanetaka Akizuki
- Department of Plastic, Reconstructive & Aesthetic Surgery, Tokyo Metropolitan Police Hospital, Tokyo, Japan
| | - Amit Gefen
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
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16
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Van Damme N, Van Hecke A, Remue E, Van den Bussche K, Moore Z, Gefen A, Verhaeghe S, Beeckman D. Physiological processes of inflammation and edema initiated by sustained mechanical loading in subcutaneous tissues: A scoping review. Wound Repair Regen 2019; 28:242-265. [DOI: 10.1111/wrr.12777] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 09/23/2019] [Accepted: 10/23/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Nele Van Damme
- Skin Integrity Research Group (SKINT), University Centre for Nursing and Midwifery, Department of Public HealthGhent University Ghent Belgium
| | - Ann Van Hecke
- University Centre for Nursing and Midwifery, Department of Public HealthGhent University Ghent Belgium
| | - Eline Remue
- University Centre for Nursing and Midwifery, Department of Public HealthGhent University Ghent Belgium
- Nursing departmentGhent University Hospital Ghent Belgium
| | - Karen Van den Bussche
- Skin Integrity Research Group (SKINT), University Centre for Nursing and Midwifery, Department of Public HealthGhent University Ghent Belgium
| | - Zena Moore
- Skin Integrity Research Group (SKINT), University Centre for Nursing and Midwifery, Department of Public HealthGhent University Ghent Belgium
- School of Nursing & MidwiferyRoyal College of Surgeons in Ireland (RCSI) Dublin Ireland
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of EngineeringTel Aviv University Tel Aviv Israel
| | - Sofie Verhaeghe
- University Centre for Nursing and Midwifery, Department of Public HealthGhent University Ghent Belgium
- Department of Health CareVIVES University of Applied Sciences Roeselare Belgium
| | - Dimitri Beeckman
- Skin Integrity Research Group (SKINT), University Centre for Nursing and Midwifery, Department of Public HealthGhent University Ghent Belgium
- School of Nursing & MidwiferyRoyal College of Surgeons in Ireland (RCSI) Dublin Ireland
- School of Health SciencesÖrebro University Örebro Sweden
- Research Unit of Plastic Surgery, Department of Clinical Research, Faculty of Health SciencesUniversity of Southern Denmark Odense Denmark
- School of Nursing and MidwiferyMonash University Melbourne Australia
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17
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How medical engineering has changed our understanding of chronic wounds and future prospects. Med Eng Phys 2019; 72:13-18. [DOI: 10.1016/j.medengphy.2019.08.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 08/27/2019] [Indexed: 12/26/2022]
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18
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Alvarez-Elizondo MB, Barenholz-Cohen T, Weihs D. Sodium pyruvate pre-treatment prevents cell death due to localised, damaging mechanical strains in the context of pressure ulcers. Int Wound J 2019; 16:1153-1163. [PMID: 31407500 DOI: 10.1111/iwj.13173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/26/2019] [Indexed: 12/27/2022] Open
Abstract
We demonstrate sodium pyruvate (NaPy) pre-treatment as a successful approach for pressure ulcer (PU) prevention by averting their aetiological origin-cell-level damage and death by large, sustained mechanical loads. We evaluated the NaPy pre-treatment effect on permeability changes in the cell's plasma membrane (PM) following application of in vitro damaging-level strains. Fibroblasts or myoblasts, respectively, models for superficial or deep-tissue damage were grown in 0 or 1 mM NaPy, emulating typical physiological or cell culture conditions. Cells were pre-treated for 4 hours with 0 to 5 mM NaPy prior to 3-hour sustained, damaging-level loads (12% strain). PM permeability was quantified by the cell uptake of small (4 kDa), fluorescent dextran compared with unstrained control using fluorescence-activated cell sorting (FACS). Pre-treatment with 1 mM, and especially 5 mM, NaPy significantly reduces damage to PM integrity. Long-term NaPy pre-exposure can improve protective treatment, affecting fibroblasts and myoblasts differently. Pre-treating with NaPy, a natural cell metabolite, allows cells under damaging-level mechanical loads to maintain their PM integrity, that is, to avoid loss of homeostasis and inevitable, eventual cell death, by preventing initial, microscale stages of PU formation. This pre-treatment may be applied prior to planned periods of immobility, for example, planned surgery or transport, to prolong safe time in a position by preventing initial cell damage that can cascade and lead to PU formation.
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Affiliation(s)
| | - Tamar Barenholz-Cohen
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Daphne Weihs
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
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19
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Abstract
In this article, the vulnerability of the soft tissues of the heel to pressure ulcers (injuries) is explained from a biomechanical engineering perspective, and emerging technologies for protecting the heel, particularly low-friction garments, are reviewed. Sustained deformations in the soft tissue of the weight-bearing posterior heel cause progressive cell and tissue damage due to loss of homeostasis in the cells, as the cytoskeleton and plasma membranes of the affected cells lose integrity and functionality. This deformation damage onsets and evolves rapidly when there is no relief of the tissue distortion (e.g. in supine motionless lying). Hence, prevention should be timely and be applied across all patient populations that are at risk. In particular there is a need to protect tissues from the action of frictional forces that are shearing not only the skin but also the deep tissue structures of the heel. The internal anatomy and physiology of the posterior heel, the common hospital conditions (lying supine, head of the bed elevated) and medical conditions involving neuropathy and perfusion impairments may impose specific risk for heel (pressure) ulcers. There is growing evidence that low-friction-fabric garments may provide added benefits in preventing heel ulcers when used in addition to standard clinical and technology-supported pressure ulcer prevention strategies, as the low-friction fabric structures absorb frictional forces before these are able to considerably distort the susceptible heel tissues.
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Affiliation(s)
- Amit Gefen
- Professor in Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Israel
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20
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Gould LJ, Bohn G, Bryant R, Paine T, Couch K, Cowan L, McFarland F, Simman R. Pressure ulcer summit 2018: An interdisciplinary approach to improve our understanding of the risk of pressure‐induced tissue damage. Wound Repair Regen 2019; 27:497-508. [DOI: 10.1111/wrr.12730] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/12/2019] [Accepted: 05/07/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Lisa J. Gould
- South Shore Hospital Center for Wound Healing Weymouth Massachusetts
| | | | - Ruth Bryant
- Abbott Northwestern Hospital Minneapolis Minnesota
| | - Tim Paine
- Department of RehabilitationLitchfield Hills Orthopedic Torrington Connecticut
| | - Kara Couch
- Wound Healing and Limb Preservation CenterGeorge Washington University Hospital Washington District of Columbia
| | - Linda Cowan
- Center of Innovation on Disability and Rehabilitation ResearchVirginia Health Care Richmond Virginia
| | | | - Richard Simman
- Jobst Vascular InstituteUniversity of Toledo College of Medicine Toledo Ohio
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21
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LaPlaca MC, Lessing MC, Prado GR, Zhou R, Tate CC, Geddes-Klein D, Meaney DF, Zhang L. Mechanoporation is a potential indicator of tissue strain and subsequent degeneration following experimental traumatic brain injury. Clin Biomech (Bristol, Avon) 2019; 64:2-13. [PMID: 29933966 DOI: 10.1016/j.clinbiomech.2018.05.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 05/25/2018] [Accepted: 05/31/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND An increases in plasma membrane permeability is part of the acute pathology of traumatic brain injury and may be a function of excessive membrane force. This membrane damage, or mechanoporation, allows non-specific flux of ions and other molecules across the plasma membrane, and may ultimately lead to cell death. The relationships among tissue stress and strain, membrane permeability, and subsequent cell degeneration, however, are not fully understood. METHODS Fluorescent molecules of different sizes were introduced to the cerebrospinal fluid space prior to injury and animals were sacrificed at either 10 min or 24 h after injury. We compared the spatial distribution of plasma membrane damage following controlled cortical impact in the rat to the stress and strain tissue patterns in a 3-D finite element simulation of the injury parameters. FINDINGS Permeable cells were located primarily in the ipsilateral cortex and hippocampus of injured rats at 10 min post-injury; however by 24 h there was also a significant increase in the number of permeable cells. Analysis of colocalization of permeability marker uptake and Fluorojade staining revealed a subset of permeable cells with signs of degeneration at 24 h, but plasma membrane damage was evident in the vast majority of degenerating cells. The regional and subregional distribution patterns of the maximum principal strain and shear stress estimated by the finite element model were comparable to the cell membrane damage profiles following a compressive impact. INTERPRETATION These results indicate that acute membrane permeability is prominent following traumatic brain injury in areas that experience high shear or tensile stress and strain due to differential mechanical properties of the cell and tissue organization, and that this mechanoporation may play a role in the initiation of secondary injury, contributing to cell death.
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Affiliation(s)
- Michelle C LaPlaca
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Dr., Atlanta, GA 030332-0535, USA.
| | - M Christian Lessing
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Dr., Atlanta, GA 030332-0535, USA
| | - Gustavo R Prado
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Dr., Atlanta, GA 030332-0535, USA
| | - Runzhou Zhou
- Department of Biomedical Engineering, Wayne State University, 818 W Hancock St., Detroit, MI 48201, USA
| | - Ciara C Tate
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Dr., Atlanta, GA 030332-0535, USA
| | - Donna Geddes-Klein
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd St., Philadelphia, PA 19104-6321, USA
| | - David F Meaney
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd St., Philadelphia, PA 19104-6321, USA
| | - Liying Zhang
- Department of Biomedical Engineering, Wayne State University, 818 W Hancock St., Detroit, MI 48201, USA
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22
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Traa WA, van Turnhout MC, Nelissen JL, Strijkers GJ, Bader DL, Oomens CWJ. There is an individual tolerance to mechanical loading in compression induced deep tissue injury. Clin Biomech (Bristol, Avon) 2019; 63:153-160. [PMID: 30897463 DOI: 10.1016/j.clinbiomech.2019.02.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/14/2019] [Accepted: 02/22/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Deep tissue injury is a type of pressure ulcer which originates subcutaneously due to sustained mechanical loading. The relationship between mechanical compression and damage development has been extensively studied in 2D. However, recent studies have suggested that damage develops beyond the site of indentation. The objective of this study was to compare mechanical loading conditions to the associated damage in 3D. METHODS An indentation test was performed on the tibialis anterior muscle of rats (n = 39). Changes in the form of oedema and structural damage were monitored with MRI in an extensive region. The internal deformations were evaluated using MRI based 3D finite element models. FINDINGS Damage propagates away from the loaded region. The 3D analysis indicates that there is a subject specific tolerance to compression induced deep tissue injury. INTERPRETATION Individual tolerance is an important factor when considering the mechanical loading conditions which induce damage.
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Affiliation(s)
- Willeke A Traa
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands.
| | - Mark C van Turnhout
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Jules L Nelissen
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; Department of Radiology and Nuclear Medicine, Academic Medical Center, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Biomedical Engineering and Physics, Meibergdreef 9, Amsterdam, the Netherlands
| | - Gustav J Strijkers
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; Amsterdam UMC, University of Amsterdam, Biomedical Engineering and Physics, Meibergdreef 9, Amsterdam, the Netherlands
| | - Dan L Bader
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands; Faculty of Health Sciences, University of Southampton, Southampton, United Kingdom
| | - Cees W J Oomens
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands
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23
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Santamaria N, Creehan S, Fletcher J, Alves P, Gefen A. Preventing pressure injuries in the emergency department: Current evidence and practice considerations. Int Wound J 2019; 16:746-752. [PMID: 30815991 DOI: 10.1111/iwj.13092] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/16/2019] [Accepted: 01/21/2019] [Indexed: 12/13/2022] Open
Abstract
The emergency department (ED) is at the front line of hospital pressure injury (PI) prevention, yet ED clinicians must balance many competing clinical priorities in the care of seriously ill patients. This paper presents the current biomechanical and clinical evidence and management considerations to assist EDs to continue to develop and implement evidence-based PI prevention protocols for the high-risk emergency/trauma patient. The prevention of hospital-acquired pressure injuries has received significant focus internationally over many years because of the additional burden that these injuries place on the patient, the additional costs and impact to the efficiency of the hospital, and the potential for litigation. The development of a PI is the result of a complex number of biomechanical, physiological, and environmental interactions. Our understanding of the interaction of these factors has improved significantly over the past 10 years. We have demonstrated that large reductions in PI incidence rates can be achieved in critical care and general hospital wards through the application of advanced evidence-based prevention protocols and believe that further improvement can be achieved through the application of these approaches in the ED.
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Affiliation(s)
- Nick Santamaria
- Department of Nursing, University of Melbourne, Melbourne, Victoria, Australia
| | - Sue Creehan
- Department of Nursing, Virginia Commonwealth University, Richmond, Virginia
| | | | - Paulo Alves
- Department of Nursing, Catholic University of Portugal, Lisbon, Portugal
| | - Amit Gefen
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
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24
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Marom A, Berkovitch Y, Toume S, Alvarez-Elizondo MB, Weihs D. Non-damaging stretching combined with sodium pyruvate supplement accelerate migration of fibroblasts and myoblasts during gap closure. Clin Biomech (Bristol, Avon) 2019; 62:96-103. [PMID: 30711737 DOI: 10.1016/j.clinbiomech.2019.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 01/09/2019] [Accepted: 01/27/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Sustained, low- and mid-level (3-6%), radial stretching combined with varying concentrations of sodium pyruvate (NaPy) supplement increase the migration rate during microscale gap closure following an in vitro injury; NaPy is a physiological supplement often used in cell-culture media. Recently we showed that low-level tensile strains accelerate in vitro kinematics during en masse cell migration; topically applied mechanical deformations also accelerate in vivo healing in larger wounds. The constituents and nutrients at injury sites change. Thus, we combine a supplement with stretching conditions to effectively accelerate wound healing. METHODS Monolayers of murine fibroblasts (NIH3T3) or myoblasts (C2C12) were cultured in 1 mM NaPy on stretchable, linear-elastic substrates. Monolayers were subjected to 0, 3, or 6% stretching using a custom three-dimensionally printed stretching apparatus, micro-damage was immediately induced, media was replaced with fresh media containing 0, 1, or 5 mM NaPy, and cell migration kinematics during gap-closure were quantitatively evaluated. FINDINGS In myoblasts, the smallest evaluated strain (3%, minimal risk of damage) combined with preinjury (1 mM) and post-injury exogenous NaPy supplements accelerated gap closure in a statistically significant manner; response was NaPy concentration dependent. In both fibroblasts and myoblasts, when cells were pre-exposed to NaPy, yet no supplement was provided post-injury, mid-level stretches (6%) compensated for post-injury deficiency in exogenous NaPy and accelerated gap-closure in a statistically significant manner. INTERPRETATION Small deformations combined with NaPy supplement prior-to and following cell-damage accelerate en masse cell migration and can be applied in wound healing, e.g. to preventatively accelerate closure of microscale gaps.
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Affiliation(s)
- Anat Marom
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Yulia Berkovitch
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Samer Toume
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | | | - Daphne Weihs
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
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25
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Microclimate: A critical review in the context of pressure ulcer prevention. Clin Biomech (Bristol, Avon) 2018; 59:62-70. [PMID: 30199821 DOI: 10.1016/j.clinbiomech.2018.09.010] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 08/01/2018] [Accepted: 09/04/2018] [Indexed: 02/07/2023]
Abstract
Pressure ulcers are caused by sustained mechanical loading and deformation of the skin and subcutaneous layers between internal stiff anatomical structures and external surfaces or devices. In addition, the skin microclimate (temperature, humidity and airflow next to the skin surface) is an indirect pressure ulcer risk factor. Temperature and humidity affect the structure and function of the skin increasing or lowering possible damage thresholds for the skin and underlying soft tissues. From a pressure ulcer prevention research perspective, the effects of humidity and temperature next to the skin surface are inextricably linked to concurrent soft tissue deformation. Direct clinical evidence supporting the association between microclimate and pressure ulceration is sparse and of high risk of bias. Currently, it is recommended to keep the skin dry and cool and/or to allow recovery periods between phases of occlusion. The stratum corneum must be prevented from becoming overhydrated or from drying out but exact ranges of an acceptable microclimate are unknown. Therefore, vague terms like 'microclimate management' should be avoided but product and microclimate characteristics should be explicitly stated to allow an informed decision making. Pressure ulcer prevention interventions like repositioning, the use of special support surfaces, cushions, and prophylactic dressings are effective only if they reduce sustained deformations in soft tissues. This mode of action outweighs possible undesirable microclimate properties. As long as uncertainty exists efforts must be taken to use as less occlusive materials as possible. There seems to be individual intrinsic characteristics making patients more vulnerable to microclimate effects.
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26
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Yang H, Yao Y, Li H, Ho LWC, Yin B, Yung WY, Leung KCF, Mak AFT, Choi CHJ. Promoting intracellular delivery of sub-25 nm nanoparticles via defined levels of compression. NANOSCALE 2018; 10:15090-15102. [PMID: 30059120 DOI: 10.1039/c8nr04927k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Many investigations into the interactions between nanoparticles and mammalian cells entail the use of culture systems that do not account for the effect of extracellular mechanical cues, such as compression. In this work, we present an experimental set-up to systematically investigate the combined effects of nanoparticle size and compressive stress on the cellular uptake and intracellular localization of poly(ethylene glycol)-coated gold nanoparticles (Au-PEG NPs). Specifically, we employ an automated micromechanical system to apply defined levels of compressive strain to an agarose gel, which transmits defined amounts of unconfined, uniaxial compressive stress to a monolayer of C2C12 mouse myoblasts seeded underneath the gel without compromising cell viability. Notably, uptake of Au-PEG NPs smaller than 25 nm by compressed myoblasts is up to 5-fold higher than that by uncompressed cells. The optimal compressive stress for maximizing the cellular uptake of sub-25 nm NPs monotonically increases with NP size. With and without compression, the Au-PEG NPs enter C2C12 cells via energy-dependent uptake; they also enter compressed cells via clathrin-mediated endocytosis as the major pathway. Upon cellular entry, the Au-PEG NPs more readily reside in the late endosomes or lysosomes of compressed cells than uncompressed cells. Results from our experimental set-up yield mechanistic insights into the delivery of NPs to cell types under extracellular compression.
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Affiliation(s)
- Hongrong Yang
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
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27
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Santamaria N, Gerdtz M, Kapp S, Wilson L, Gefen A. A randomised controlled trial of the clinical effectiveness of multi-layer silicone foam dressings for the prevention of pressure injuries in high-risk aged care residents: The Border III Trial. Int Wound J 2018; 15:482-490. [PMID: 29635842 DOI: 10.1111/iwj.12891] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 12/31/2017] [Indexed: 12/11/2022] Open
Abstract
Pressure injuries are prevalent in highly dependent aged care residents. This study investigated the clinical effectiveness of the application of the Mepilex Border Sacrum and Mepilex Heel dressings to prevent the development of facility-acquired pressure injuries. A total of 288 recently admitted residents were enrolled from 40 Australian nursing homes into a randomised controlled trial. Residents randomised to standard care (n = 150) received pressure injury prevention as recommended by international guidelines. Residents randomised to the intervention (n = 138) received standard pressure injury prevention care and had dressings applied to their sacrum and heels. Participants were comparable on demographic and physiological parameters. More residents in the control group developed pressure injuries than in the intervention group (16 vs 3, P = 0.004), and they developed more pressure injuries in total than residents in the intervention group. The results represent a relative risk reduction of 80% for residents treated with the dressings and for every 12 patients that we treated we prevented one pressure injury. Based on our findings, we conclude that the use of the Mölnlycke Mepilex Border Sacrum and Mepilex Heel dressings confers a significant additional protective benefit to nursing home residents with a high risk of developing a facility-acquired pressure injury.
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Affiliation(s)
- Nick Santamaria
- Department of Nursing, University of Melbourne, Melbourne, Australia
| | - Marie Gerdtz
- Department of Nursing, University of Melbourne, Melbourne, Australia
| | - Suzanne Kapp
- Department of Nursing, University of Melbourne, Melbourne, Australia
| | - Lauren Wilson
- Department of Nursing, University of Melbourne, Melbourne, Australia
| | - Amit Gefen
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
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28
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Lustig M, Gefen A, Benayahu D. Adipogenesis and lipid production in adipocytes subjected to sustained tensile deformations and elevated glucose concentration: a living cell-scale model system of diabesity. Biomech Model Mechanobiol 2018; 17:903-913. [PMID: 29335836 DOI: 10.1007/s10237-017-1000-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/29/2017] [Indexed: 12/15/2022]
Abstract
Adipocyte fate commitment is characterized by morphological changes of fibroblastic pre-adipocyte cells, and specifically by accumulation of lipid droplets (LDs) as part of the adipogenesis metabolism. Formation of LDs indicates the production of triglycerides from glucose through an insulin-regulated glucose internalization process. In obesity, adipocytes typically become insulin resistant, and glucose transport into the cells is impaired, resulting in type 2 diabetes. In the present study, we monitored the adipogenesis in 3T3-L1 cultured cells exposed to high (450 mg/dL hyperglycemia) and low (100 mg/dL physiological) glucose concentrations, in a novel cell culture model system of diabesity. In addition to glucose conditions, cells were concurrently exposed to different substrate tensile strains (12% and control) based on our prior work which revealed that adipogenesis is accelerated in cultures subjected to static, chronic substrate tensile deformations. Phase-contrast images were taken throughout the adipogenesis process (3 weeks) and were analyzed by an image processing algorithm which quantitatively monitors cell differentiation and lipid accumulation (number of LDs per cell and their radius as well as cell size and shape). The results indicated that high glucose concentrations and substrate tensile strains delivered to adipocytes accelerated lipid production by 1.7- and 1.4-fold, respectively. In addition, significant changes in average cell projected area and in other morphological attributes were observed during the differentiation process. The importance of this study is in characterizing the adipogenesis parameters as potential read-outs that can predict the occurrence of insulin resistance in the development of diabesity.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Dafna Benayahu
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel.
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Abdalrahman T, Dubuis L, Green J, Davies N, Franz T. Cellular mechanosensitivity to substrate stiffness decreases with increasing dissimilarity to cell stiffness. Biomech Model Mechanobiol 2017; 16:2063-2075. [PMID: 28733924 DOI: 10.1007/s10237-017-0938-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 07/11/2017] [Indexed: 01/07/2023]
Abstract
Computational modelling has received increasing attention to investigate multi-scale coupled problems in micro-heterogeneous biological structures such as cells. In the current study, we investigated for a single cell the effects of (1) different cell-substrate attachment (2) and different substrate modulus [Formula: see text] on intracellular deformations. A fibroblast was geometrically reconstructed from confocal micrographs. Finite element models of the cell on a planar substrate were developed. Intracellular deformations due to substrate stretch of [Formula: see text], were assessed for: (1) cell-substrate attachment implemented as full basal contact (FC) and 124 focal adhesions (FA), respectively, and [Formula: see text]140 KPa and (2) [Formula: see text], 140, 1000, and 10,000 KPa, respectively, and FA attachment. The largest strains in cytosol, nucleus and cell membrane were higher for FC (1.35[Formula: see text], 0.235[Formula: see text] and 0.6[Formula: see text]) than for FA attachment (0.0952[Formula: see text], 0.0472[Formula: see text] and 0.05[Formula: see text]). For increasing [Formula: see text], the largest maximum principal strain was 4.4[Formula: see text], 5[Formula: see text], 5.3[Formula: see text] and 5.3[Formula: see text] in the membrane, 9.5[Formula: see text], 1.1[Formula: see text], 1.2[Formula: see text] and 1.2[Formula: see text] in the cytosol, and 4.5[Formula: see text], 5.3[Formula: see text], 5.7[Formula: see text] and 5.7[Formula: see text] in the nucleus. The results show (1) the importance of representing FA in cell models and (2) higher cellular mechanical sensitivity for substrate stiffness changes in the range of cell stiffness. The latter indicates that matching substrate stiffness to cell stiffness, and moderate variation of the former is very effective for controlled variation of cell deformation. The developed methodology is useful for parametric studies on cellular mechanics to obtain quantitative data of subcellular strains and stresses that cannot easily be measured experimentally.
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Affiliation(s)
- Tamer Abdalrahman
- Division of Biomedical Engineering, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa
| | - Laura Dubuis
- Division of Biomedical Engineering, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa
| | - Jason Green
- Cardiovascular Research Unit, Chris Barnard Division of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa
| | - Neil Davies
- Cardiovascular Research Unit, Chris Barnard Division of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa
| | - Thomas Franz
- Division of Biomedical Engineering, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa. .,Bioengineering Science Research Group, Engineering Sciences, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK.
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Toume S, Gefen A, Weihs D. Low-level stretching accelerates cell migration into a gap. Int Wound J 2016; 14:698-703. [PMID: 27748039 DOI: 10.1111/iwj.12679] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 08/29/2016] [Accepted: 09/12/2016] [Indexed: 01/03/2023] Open
Abstract
We observed that radially stretching cell monolayers at a low level (3%) increases the rate at which they migrate to close a gap formed by in vitro injury. Wound healing has been shown to accelerate in vivo when deformations are topically applied, for example, by negative pressure wound therapy. However, the direct effect of deformations on cell migration during gap closure is still unknown. Thus, we have evaluated the effect of radially applied, sustained (static) tensile strain on the kinematics of en mass cell migration. Monolayers of murine fibroblasts were cultured on stretchable, linear-elastic substrates that were subjected to different tensile strains, using a custom-designed three-dimensionally printed stretching apparatus. Immediately following stretching, the monolayer was 'wounded' at its centre, and cell migration during gap closure was monitored and quantitatively evaluated. We observed a significant increase in normalised migration rates and a reduction of gap closure time with 3% stretching, relative to unstretched controls or 6% stretch. Interestingly, the initial gap area was linearly correlated with the maximum migration rate, especially when stretching was applied. Therefore, small deformations applied to cell monolayers during gap closure enhance en mass cell migration associated with wound healing and can be used to fine-tune treatment protocols.
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Affiliation(s)
- Samer Toume
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Daphne Weihs
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
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31
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Yao Y, Da Ong LX, Li X, Wan K, Mak AFT. Effects of Biowastes Released by Mechanically Damaged Muscle Cells on the Propagation of Deep Tissue Injury: A Multiphysics Study. Ann Biomed Eng 2016; 45:761-774. [PMID: 27624658 DOI: 10.1007/s10439-016-1731-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/07/2016] [Indexed: 12/24/2022]
Abstract
Deep tissue injuries occur in muscle tissues around bony prominences under mechanical loading leading to severe pressure ulcers. Tissue compression can potentially compromise lymphatic transport and cause accumulation of metabolic biowastes, which may cause further cell damage under continuous mechanical loading. In this study, we hypothesized that biowastes released by mechanically damaged muscle cells could be toxic to the surrounding muscle cells and could compromise the capability of the surrounding muscle cells to withstand further mechanical loadings. In vitro, we applied prolonged low compressive stress (PLCS) and short-term high compressive stress to myoblasts to cause cell damage and collected the biowastes released by the damaged cells under the respective loading scenarios. In silico, we used COMSOL to simulate the compressive stress distribution and the diffusion of biowastes in a semi-3D buttock finite element model. In vitro results showed that biowastes collected from cells damaged under PLCS were more toxic and could compromise the capability of normal myoblasts to resist compressive damage. In silico results showed that higher biowastes diffusion coefficient, higher biowastes release rate, lower biowastes tolerance threshold and earlier timeline of releasing biowastes would cause faster propagation of tissue damage. This study highlighted the importance of biowastes in the development of deep tissue injury to clinical pressure ulcers under prolonged skeletal compression.
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Affiliation(s)
- Yifei Yao
- Division of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Lucas Xian Da Ong
- Division of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Xiaotong Li
- Division of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Kinlun Wan
- Division of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Arthur F T Mak
- Division of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China.
- Division of Biomedical Engineering, The Chinese University of Hong Kong, Rm. 429, Ho Sin Hang Engineering Building, Shatin, N.T., Hong Kong SAR, China.
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32
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Alihemmati Z, Vahidi B, Haghighipour N, Salehi M. Computational simulation of static/cyclic cell stimulations to investigate mechanical modulation of an individual mesenchymal stem cell using confocal microscopy. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 70:494-504. [PMID: 27770921 DOI: 10.1016/j.msec.2016.09.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/09/2016] [Accepted: 09/08/2016] [Indexed: 01/27/2023]
Abstract
It has been found that cells react to mechanical stimuli, while the type and magnitude of these cells are different in various physiological and pathological conditions. These stimuli may affect cell behaviors via mechanotransduction mechanisms. The aim of this study is to evaluate mechanical responses of a mesenchymal stem cell (MSC) to a pressure loading using finite elements method (FEM) to clarify procedures of MSC mechanotransduction. The model is constructed based on an experimental set up in which statics and cyclic compressive loads are implemented on a model constructed from a confocal microscopy 3D image of a stem cell. Both of the applied compressive loads are considered in the physiological loading regimes. Moreover, a viscohyperelastic material model was assumed for the cell through which the finite elements simulation anticipates cell behavior based on strain and stress distributions in its components. As a result, high strain and stress values were captured from the viscohyperelastic model because of fluidic behavior of cytosol when compared with the obtained results through the hyperelastic models. It can be concluded that the generated strain produced by cyclic pressure is almost 8% higher than that caused by the static load and the von Mises stress distribution is significantly increased to about 150kPa through the cyclic loading. In total, the results does not only trace the efficacy of an individual 3D model of MSC using biomechanical experiments of cell modulation, but these results provide knowledge in interpretations from cell geometry. The current study was performed to determine a realistic aspect of cell behavior.
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Affiliation(s)
- Zakieh Alihemmati
- Division of Biomedical Engineering, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Bahman Vahidi
- Division of Biomedical Engineering, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran.
| | | | - Mohammad Salehi
- Department of Mechanical Engineering, University of Tehran, Tehran, Iran
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33
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Gefen A, Weihs D. Cytoskeleton and plasma-membrane damage resulting from exposure to sustained deformations: A review of the mechanobiology of chronic wounds. Med Eng Phys 2016; 38:828-33. [DOI: 10.1016/j.medengphy.2016.05.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 05/19/2016] [Accepted: 05/23/2016] [Indexed: 12/14/2022]
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34
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Gefen A, Weihs D. Mechanical cytoprotection: A review of cytoskeleton-protection approaches for cells. J Biomech 2016; 49:1321-1329. [DOI: 10.1016/j.jbiomech.2015.10.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 10/20/2015] [Accepted: 10/21/2015] [Indexed: 12/28/2022]
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35
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Printable low-cost, sustained and dynamic cell stretching apparatus. J Biomech 2016; 49:1336-1339. [DOI: 10.1016/j.jbiomech.2016.03.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/13/2016] [Accepted: 03/16/2016] [Indexed: 12/30/2022]
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36
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Effects of oxidative stress-induced changes in the actin cytoskeletal structure on myoblast damage under compressive stress: confocal-based cell-specific finite element analysis. Biomech Model Mechanobiol 2016; 15:1495-1508. [DOI: 10.1007/s10237-016-0779-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/03/2016] [Indexed: 01/07/2023]
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37
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Jagannathan NS, Tucker-Kellogg L. Membrane permeability during pressure ulcer formation: A computational model of dynamic competition between cytoskeletal damage and repair. J Biomech 2015; 49:1311-1320. [PMID: 26772800 DOI: 10.1016/j.jbiomech.2015.12.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 12/11/2015] [Accepted: 12/14/2015] [Indexed: 10/22/2022]
Abstract
Pressure ulcers are debilitating wounds that arise frequently in people who have lost mobility. Mechanical stress, oxidative stress and ischemia-reperfusion injury are potential sources of damage during pressure ulcer formation, but cross-talk between these sources has rarely been investigated. In vitro experiments with mechanically-induced cell damage previously demonstrated that non-lethal amounts of static cell deformation could induce myoblast membrane permeabilization. Permeabilization, in turn, has the potential to induce oxidative stress via leakage of calcium, myoglobin or alarmins. In this work, we constructed a hypothetical causal network of cellular-scale effects resulting from deformation and permeabilization, and we investigated the theoretical sensitivity of cell death toward various parameters and pathways of the model. Simulations showed that the survival/death outcome was particularly sensitive to the speed of membrane repair. The outcome was also sensitive to whether oxidative stress could decrease the speed of membrane repair. Finally, using the assumption that apoptosis and necrosis would have opposite effects on membrane leakage in dying cells, we showed that promoting apoptosis might under certain conditions have the paradoxical effect of decreasing, rather than increasing, total cell death. Our work illustrates that apoptosis may have hidden benefits at preventing spatial spread of death. More broadly, our work shows the importance of membrane repair dynamics and highlights the need for experiments to measure the effects of ischemia, apoptosis induction, and other co-occurring sources of cell stress toward the speed of membrane repair.
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Affiliation(s)
- N Suhas Jagannathan
- Centre for Computational Biology, and Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore
| | - Lisa Tucker-Kellogg
- Centre for Computational Biology, and Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore; Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore; BioSystems and Micromechanics (BioSyM) Singapore-MIT Alliance for Research and Technology, 1 Create Way, Singapore.
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38
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Webb R. How has our view of pressure ulcers changed and what does the future hold? J Wound Care 2015; 24:587-8. [PMID: 26654739 DOI: 10.12968/jowc.2015.24.12.587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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39
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Contoured Foam Cushions Cannot Provide Long-term Protection Against Pressure-Ulcers for Individuals with a Spinal Cord Injury. Adv Skin Wound Care 2015; 28:303-16. [DOI: 10.1097/01.asw.0000465300.99194.27] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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40
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Katzengold R, Shoham N, Benayahu D, Gefen A. Simulating single cell experiments in mechanical testing of adipocytes. Biomech Model Mechanobiol 2014; 14:537-47. [DOI: 10.1007/s10237-014-0620-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 09/04/2014] [Indexed: 01/25/2023]
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41
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Levy A, Kopplin K, Gefen A. Computer simulations of efficacy of air-cell-based cushions in protecting against reoccurrence of pressure ulcers. ACTA ACUST UNITED AC 2014; 51:1297-319. [DOI: 10.1682/jrrd.2014.02.0048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 07/03/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Ayelet Levy
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Israel
| | | | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Israel
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42
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Chenu O, Vuillerme N, Bucki M, Diot B, Cannard F, Payan Y. TexiCare: An innovative embedded device for pressure ulcer prevention. Preliminary results with a paraplegic volunteer. J Tissue Viability 2013; 22:83-90. [DOI: 10.1016/j.jtv.2013.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 05/17/2013] [Accepted: 05/20/2013] [Indexed: 11/25/2022]
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43
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Leopold E, Gefen A. Changes in permeability of the plasma membrane of myoblasts to fluorescent dyes with different molecular masses under sustained uniaxial stretching. Med Eng Phys 2013; 35:601-7. [DOI: 10.1016/j.medengphy.2012.07.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 06/28/2012] [Accepted: 07/12/2012] [Indexed: 01/27/2023]
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44
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Solis LR, Twist E, Seres P, Thompson RB, Mushahwar VK. Prevention of deep tissue injury through muscle contractions induced by intermittent electrical stimulation after spinal cord injury in pigs. J Appl Physiol (1985) 2012; 114:286-96. [PMID: 23172030 DOI: 10.1152/japplphysiol.00257.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Deep tissue injury (DTI) is a severe medical complication that commonly affects those with spinal cord injury. It is caused by prolonged external loading of the muscles, entrapping them between a bony prominence and the support surface. The entrapment causes excessive mechanical deformation and increases in interstitial pressure, leading to muscle breakdown deep around the bony prominences. We proposed the use of intermittent electrical stimulation (IES) as a novel prophylactic method for the prevention of DTI. In this study, we assessed the long-term effectiveness of this technique in pigs that had received a partial spinal cord injury that paralyzed one hindlimb. The pigs recovered for 2 wk postsurgery, and subsequently, their paralyzed limbs were loaded to 25% of their body weights 4 h/day for 4 consecutive days each week for 1 mo. One group of pigs (n = 3) received IES during the loading, whereas another group (n = 3) did not. DTI was quantified using magnetic resonance imaging (MRI) and postmortem histology. In the group that did not receive IES, MRI assessments revealed signs of tissue damage in 48% of the volume of the loaded muscle. In the group that did receive IES, only 8% of the loaded muscle volume showed signs of tissue damage. Similar findings were found through postmortem histology. This study demonstrates, for the first time, that IES may be an effective technique for preventing the formation of DTI in loaded muscles after spinal cord injury.
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Affiliation(s)
- Leandro R Solis
- Rehabilitation Science Program, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada
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45
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Shoham N, Gefen A. Deformations, mechanical strains and stresses across the different hierarchical scales in weight-bearing soft tissues. J Tissue Viability 2012; 21:39-46. [DOI: 10.1016/j.jtv.2012.03.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 02/03/2012] [Accepted: 03/25/2012] [Indexed: 01/23/2023]
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46
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Leopold E, Gefen A. A simple stochastic model to explain the sigmoid nature of the strain-time cellular tolerance curve. J Tissue Viability 2012; 21:27-36. [DOI: 10.1016/j.jtv.2011.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Revised: 11/20/2011] [Accepted: 11/29/2011] [Indexed: 12/12/2022]
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47
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Levy A, Enzer S, Shoham N, Zaretsky U, Gefen A. Large, but not small sustained tensile strains stimulate adipogenesis in culture. Ann Biomed Eng 2011; 40:1052-60. [PMID: 22203192 DOI: 10.1007/s10439-011-0496-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 12/17/2011] [Indexed: 12/13/2022]
Abstract
Understanding the mechanoresponsiveness of adipocytes and the characteristics of the mechanical stimuli that regulate adipogenesis is critically important in establishing knowledge in regard to the long-term effects of a sedentary lifestyle (or immobility in extreme medical conditions) as well as concerning obesity and related diseases. In this study we subjected 3T3-L1 preadipocytes cultured on elastic substrata to different levels of static equiaxial tensile strains within the physiological range, up to substrate tensile strain (STS) of 12%, while inducing differentiation in the cultures. Based on prior work which revealed that adipogenesis is accelerated in cultures subjected to STS of 12% by activating the mitogen-activated protein kinase kinase signaling pathway, we were specifically interested in identifying the STS levels which trigger this process. We hence monitored the production and accumulation of lipid droplets (LDs) using a non-destructive, image-processing-based method that we have previously developed, for a period of 4 weeks. The experimental data demonstrated accelerated adipogenesis in the cultures subjected to STS levels of 6%, 9%, and 12% with respect to cultures subjected to STS of 3% and (non-stretched) control cultures. This accelerated adipogenic response to the large sustained STS manifested in significantly larger numbers and greater sizes of LDs in the cultures that were stretched to large STS levels (p < 0.05), starting at approximately day 14 following induction of differentiation. Hence, indeed, there appears to be a certain tensile strain threshold, or domain-which is found within the physiological range-above which the responsiveness of adipocytes to sustained static stretching increases and is manifested in accelerated adipogenesis.
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Affiliation(s)
- Ayelet Levy
- Department of Biomedical Engineering, Tel Aviv University, 69978 Tel Aviv, Israel
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