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Martyts A, Sachs D, Hiebert P, Junker H, Robmann S, Hopf R, Steenbock H, Brinckmann J, Werner S, Giampietro C, Mazza E. Biomechanical and biochemical changes in murine skin during development and aging. Acta Biomater 2024; 186:316-329. [PMID: 39009208 DOI: 10.1016/j.actbio.2024.07.013] [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: 04/10/2024] [Revised: 06/21/2024] [Accepted: 07/10/2024] [Indexed: 07/17/2024]
Abstract
Aging leads to biochemical and biomechanical changes in skin, with biological and functional consequences. Despite extensive literature on skin aging, there is a lack of studies which investigate the maturation of the tissue and connect the microscopic changes in the skin to its macroscopic biomechanical behavior as it evolves over time. The present work addresses this knowledge gap using multiscale characterization of skin in a murine model considering newborn, adult and aged mice. Monotonic uniaxial loading, tension relaxation with change of bath, and loading to failure tests were performed on murine skin samples from different age groups, complemented by inflation experiments and atomic force microscopy indentation measurements. In parallel, skin samples were characterized using histological and biochemical techniques to assess tissue morphology, collagen organization, as well as collagen content and cross-linking. We show that 1-week-old skin differs across nearly all measured parameters from adult skin, showing reduced strain stiffening and tensile strength, a thinner dermis, lower collagen content and altered crosslinking patterns. Surprisingly, adult and aged skin were similar across most biomechanical parameters in the physiologic loading range, while aged skin had lower tensile strength and lower stiffening behavior at large force values. This correlates with altered collagen content and cross-links. Based on a computational model, differences in mechanocoupled stimuli in the skin of the different age groups were calculated, pointing to a potential biological significance of the age-induced biomechanical changes in regulating the local biophysical environment of dermal cells. STATEMENT OF SIGNIFICANCE: Skin microstructure and the emerging mechanical properties change with age, leading to biological, functional and health-related consequences. Despite extensive literature on skin aging, only very limited quantitative data are available on microstructural changes and the corresponding macroscopic biomechanical behavior as they evolve over time. This work provides a wide-range multiscale mechanical characterization of skin of newborn, adult and aged mice, and quantifies microstructural correlations in tissue morphology, collagen content, organization and cross-linking. Remarkably, aged skin retained normal hydration and normal biomechanical function in the physiological loading range but showed significantly reduced properties at super-physiological loading. Our data show that age-related microstructural differences have a profound effect not only on tissue-level properties but also on the cell-level biophysical environment.
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Affiliation(s)
- Anastasiya Martyts
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland
| | - David Sachs
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland
| | - Paul Hiebert
- Institute of Molecular Health Sciences, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Håvar Junker
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland
| | - Serjosha Robmann
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland
| | - Raoul Hopf
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland
| | - Heiko Steenbock
- Institute of Virology and Cell Biology, University of Lübeck, 23562 Lübeck, Germany
| | - Jürgen Brinckmann
- Institute of Virology and Cell Biology, University of Lübeck, 23562 Lübeck, Germany; Department of Dermatology, University of Lübeck, 23562 Lübeck, Germany
| | - Sabine Werner
- Institute of Molecular Health Sciences, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Costanza Giampietro
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Edoardo Mazza
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland.
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Wetzell B, Ork B, Softic D, Morse J, Hutchens W, Meng F, McLean JB, Moore MA, Qin X. Characterization of a full-thickness decellularized and lyophilized human placental membrane for clinical applications. Int Wound J 2024; 21:e14888. [PMID: 38686514 PMCID: PMC11058634 DOI: 10.1111/iwj.14888] [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: 03/01/2024] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 05/02/2024] Open
Abstract
Allografts derived from live-birth tissue obtained with donor consent have emerged as an important treatment option for wound and soft tissue repairs. Placental membrane derived from the amniotic sac consists of the amnion and chorion, the latter of which contains the trophoblast layer. For ease of cleaning and processing, these layers are often separated with or without re-lamination and the trophoblast layer is typically discarded, both of which can negatively affect the abundance of native biological factors and make the grafts difficult to handle. Thus, a full-thickness placental membrane that includes a fully-intact decellularized trophoblast layer was developed for homologous clinical use as a protective barrier and scaffold in soft tissue repairs. Here, we demonstrate that this full-thickness placental membrane is effectively decellularized while retaining native extracellular matrix (ECM) scaffold and biological factors, including the full trophoblast layer. Following processing, it is porous, biocompatible, supports cell proliferation in vitro, and retains its biomechanical strength and the ability to pass through a cannula without visible evidence of movement or damage. Finally, it was accepted as a natural scaffold in vivo with evidence of host-cell infiltration, angiogenesis, tissue remodelling, and structural layer retention for up to 10 weeks in a murine subcutaneous implant model.
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Affiliation(s)
- Bradley Wetzell
- Global Scientific Affairs and Clinical EngagementLifeNet Health®Virginia BeachVirginiaUSA
| | - Britini Ork
- Institute of Regenerative MedicineLifeNet HealthVirginia BeachVirginiaUSA
| | - Davorka Softic
- Institute of Regenerative MedicineLifeNet HealthVirginia BeachVirginiaUSA
| | - Jennifer Morse
- Institute of Regenerative MedicineLifeNet HealthVirginia BeachVirginiaUSA
| | - William Hutchens
- Institute of Regenerative MedicineLifeNet HealthVirginia BeachVirginiaUSA
| | - Fanwei Meng
- Institute of Regenerative MedicineLifeNet HealthVirginia BeachVirginiaUSA
| | - Julie B. McLean
- Global Scientific Affairs and Clinical EngagementLifeNet Health®Virginia BeachVirginiaUSA
| | - Mark A. Moore
- Global Scientific Affairs and Clinical EngagementLifeNet Health®Virginia BeachVirginiaUSA
| | - Xiaofei Qin
- Institute of Regenerative MedicineLifeNet HealthVirginia BeachVirginiaUSA
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Vergote S, Robmann S, Van Der Merwe J, Richter J, Deprest J, Mazza E. Preterm membranes are mechanically more resistant than term membranes. Prenat Diagn 2024; 44:317-324. [PMID: 38168862 DOI: 10.1002/pd.6511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 10/29/2023] [Accepted: 12/17/2023] [Indexed: 01/05/2024]
Abstract
OBJECTIVE To compare the biomechanical properties of fetal preterm membranes (20 + 0 weeks to 30 + 0 weeks) to those of the term (37 + 0 to 41 + 0 weeks). METHOD Amnion and chorion were manually separated and samples were cut to the required geometry. Rectangular samples with (mode 1) and without (uniaxial) a notch, were tested for tearing energy, critical elongation, and tangent stiffness. Suture retention and inter-suture distance testing investigated the effect of suture placement. RESULTS From the 15 preterm and 10 term placentas studied, no notable differences were observed in uniaxial testing. Mode 1 fracture testing showed a difference in tearing energy between the preterm and term chorion (0.025 ± 0.005 vs. 0.017 ± 0.005 J/m-1 ; p = 0.027) but not in the amnion (0.030 ± 0.017 vs. 0.029 ± 0.009 J/m-1 ; p = 0.895). Both preterm amnion and chorion showed a higher critical elongation compared with term (1.229 ± 0.057 vs. 1.166 ± 0.046; p = 0.019 and 1.307 ± 0.049 vs. 1.218 ± 0.058; p = 0.012). Preterm amnion had a higher suture retention strength than its term counterpart (0.189 ± 0.065 vs. 0.121 ± 0.031 N; p = 0.023). In inter-suture distance tests, no significant interaction was observed beyond 3 mm, but the preterm chorion showed less interaction at 1-2 mm distances. CONCLUSION Preterm membranes have equivalent or superior tensile properties to term membranes. The chorion appears to contribute to the mechanical integrity of fetal membranes, particularly in preterm stages.
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Affiliation(s)
- Simen Vergote
- Department of Obstetrics and Gynaecology, UZ Leuven, Department of Development and Regeneration, Cluster Woman and Child, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Serjosha Robmann
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Johannes Van Der Merwe
- Department of Obstetrics and Gynaecology, UZ Leuven, Department of Development and Regeneration, Cluster Woman and Child, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Jute Richter
- Department of Obstetrics and Gynaecology, UZ Leuven, Department of Development and Regeneration, Cluster Woman and Child, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Jan Deprest
- Department of Obstetrics and Gynaecology, UZ Leuven, Department of Development and Regeneration, Cluster Woman and Child, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
- Institute for Women's Health, University College London, London, UK
| | - Edoardo Mazza
- Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
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Chittajallu SNSH, Gururani H, Tse KM, Rath SN, Basu S, Chinthapenta V. Investigation of microstructural failure in the human cornea through fracture tests. Sci Rep 2023; 13:13876. [PMID: 37620375 PMCID: PMC10449857 DOI: 10.1038/s41598-023-40286-3] [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: 03/23/2023] [Accepted: 08/08/2023] [Indexed: 08/26/2023] Open
Abstract
Fracture toughness of the human cornea is one of the critical parameters in suture-involved corneal surgeries and the development of bioengineered mimetics of the human cornea. The present article systematically studied the fracture characteristics of the human cornea to evaluate its resistance to tear in the opening (Mode-I) and trouser tear mode (Mode-III). Tear experiments reveal the dependency of the fracture behavior on the notch size and its location created in the corneal specimens. The findings indicate lamellar tear and collagen fiber pull-out as a failure mechanism in trouser tear and opening mode tests, respectively. Experimental results have shown a localized variation of tear behavior in trouser tear mode and indicated an increasing resistance to tear from the corneal center to the periphery. This article demonstrated the complications of evaluating fracture toughness in opening mode and showed that the limbus was weaker than the cornea and sclera against tearing. The overall outcomes of the present study help in designing experiments to understand the toughness of the diseased tissues, understanding the effect of the suturing location and donor placement, and creating numerical models to study parameters affecting corneal replacement surgery.
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Affiliation(s)
- Sai Naga Sri Harsha Chittajallu
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad (IIT Hyderabad), Hyderabad, India
- Department of Mechanical and Product Design Engineering, Swinburne University of Technology, Melbourne, Australia
- Centre for Technology Innovation, LV Prasad Eye Institute, Hyderabad, India
| | - Himanshu Gururani
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad (IIT Hyderabad), Hyderabad, India
| | - Kwong Ming Tse
- Department of Mechanical and Product Design Engineering, Swinburne University of Technology, Melbourne, Australia
| | - Subha Narayan Rath
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Hyderabad, India
| | - Sayan Basu
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, India
| | - Viswanath Chinthapenta
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad (IIT Hyderabad), Hyderabad, India.
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Samimi K, Contreras Guzman E, Wu M, Carlson L, Feltovich H, Hall TJ, Myers KM, Oyen ML, Skala MC. Optical coherence tomography of human fetal membrane sub-layers during loading. BIOMEDICAL OPTICS EXPRESS 2023; 14:2969-2985. [PMID: 37342693 PMCID: PMC10278609 DOI: 10.1364/boe.489691] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/11/2023] [Accepted: 05/13/2023] [Indexed: 06/23/2023]
Abstract
Fetal membranes have important mechanical and antimicrobial roles in maintaining pregnancy. However, the small thickness (<800 µm) of fetal membranes places them outside the resolution limits of most ultrasound and magnetic resonance systems. Optical imaging methods like optical coherence tomography (OCT) have the potential to fill this resolution gap. Here, OCT and machine learning methods were developed to characterize the ex vivo properties of human fetal membranes under dynamic loading. A saline inflation test was incorporated into an OCT system, and tests were performed on n = 33 and n = 32 human samples obtained from labored and C-section donors, respectively. Fetal membranes were collected in near-cervical and near-placental locations. Histology, endogenous two photon fluorescence microscopy, and second harmonic generation microscopy were used to identify sources of contrast in OCT images of fetal membranes. A convolutional neural network was trained to automatically segment fetal membrane sub-layers with high accuracy (Dice coefficients >0.8). Intact amniochorion bilayer and separated amnion and chorion were individually loaded, and the amnion layer was identified as the load-bearing layer within intact fetal membranes for both labored and C-section samples, consistent with prior work. Additionally, the rupture pressure and thickness of the amniochorion bilayer from the near-placental region were greater than those of the near-cervical region for labored samples. This location-dependent change in fetal membrane thickness was not attributable to the load-bearing amnion layer. Finally, the initial phase of the loading curve indicates that amniochorion bilayer from the near-cervical region is strain-hardened compared to the near-placental region in labored samples. Overall, these studies fill a gap in our understanding of the structural and mechanical properties of human fetal membranes at high resolution under dynamic loading events.
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Affiliation(s)
- Kayvan Samimi
- Morgridge Institute for Research, Madison, WI 53715, USA
| | | | - May Wu
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Lindsey Carlson
- Department of Obstetrics and Gynecology, Intermountain Healthcare, Provo, UT 84604, USA
| | - Helen Feltovich
- Department of Obstetrics and Gynecology, Intermountain Healthcare, Provo, UT 84604, USA
| | - Timothy J. Hall
- Department of Medical Physics, University of Wisconsin, Madison, WI 53705, USA
| | - Kristin M. Myers
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - Michelle L. Oyen
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63105, USA
| | - Melissa C. Skala
- Morgridge Institute for Research, Madison, WI 53715, USA
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706, USA
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Okazaki Y, Taniguchi K, Miyamoto Y, Kinoshita S, Nakabayashi K, Kaneko K, Hamada H, Satoh T, Murashima A, Hata K. Glucocorticoids increase the risk of preterm premature rupture of membranes possibly by inducing ITGA8 gene expression in the amnion. Placenta 2022; 128:73-82. [DOI: 10.1016/j.placenta.2022.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 07/04/2022] [Accepted: 07/14/2022] [Indexed: 11/30/2022]
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Wells HC, Sizeland KH, Kirby N, Haverkamp RG. Structure and Strength of Bovine and Equine Amniotic Membrane. BIOLOGY 2022; 11:biology11081096. [PMID: 35892952 PMCID: PMC9329871 DOI: 10.3390/biology11081096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary Thin, strong scaffold materials are needed for surgical applications. There is a limited selection of available materials and new materials are required. Amnionic membrane from cattle and horses were investigated for this purpose. The structure of these materials was characterized with synchrotron techniques and the strength was measured. A possible relationship between the structure and strength was identified. These amnion materials from animal sources are strong, thin, and elastic materials, although weaker than some other collagen tissues. They may be suitable for use in surgery as an alternative to material from human donors. Abstract Thin, strong scaffold materials are needed for surgical applications. New materials are required, particularly those readily available, such as from non-human sources. Bovine amniotic membrane (antepartum) and equine amniotic membrane (postpartum) were characterized with tear and tensile tests. The structural arrangement of the collagen fibrils was determined by small-angle X-ray scattering, scanning electron microscopy, and ultrasonic imaging. Bovine amnion had a thickness-normalized tear strength of 12.6 (3.8) N/mm, while equine amnion was 14.8 (5.3) N/mm. SAXS analysis of the collagen fibril arrangement yielded an orientation index of 0.587 (0.06) and 0.681 (0.05) for bovine and equine, respectively. This may indicate a relationship between more highly aligned collagen fibrils and greater strength, as seen in other materials. Amnion from bovine or equine sources are strong, thin, elastic materials, although weaker than other collagen tissue materials commonly used, that may find application in surgery as an alternative to material from human donors.
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Affiliation(s)
- Hannah C. Wells
- School of Food and Advanced Technology, Massey University, Palmerston North 4442, New Zealand;
| | - Katie H. Sizeland
- ANSTO, Lucas Heights, NSW 2234, Australia;
- ANSTO, Clayton, VIC 3168, Australia;
| | | | - Richard G. Haverkamp
- School of Food and Advanced Technology, Massey University, Palmerston North 4442, New Zealand;
- Correspondence:
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Famos F, Avilla-Royo E, Vonzun L, Ochsenbein-Kölble N, Ehrbar M. Miniaturized bioengineered models for preterm fetal membrane healing. Fetal Diagn Ther 2022; 49:235-244. [PMID: 35709687 DOI: 10.1159/000525559] [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: 03/30/2022] [Accepted: 05/26/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION The reason for the absence of fetal membrane (FM) healing after a fetoscopic intervention is not known. We hypothesize that the lack of robust miniaturized models to study preterm FM functions is currently hampering the development of new treatments for FM healing. Specifically, miniaturized models to study preterm FM healing with minimal amounts of tissue are currently lacking. METHODS In this study, we collected FMs from planned cesarean deliveries and developed different ex vivo models with an engineered biomaterial to study FM healing. Then, the effect of PDGF-BB on the migration of cells from preterm and term FMs was evaluated. RESULTS FMs could be viably cultured ex vivo for 14 days. In a model of punctured FMs, migration of cells into FM defects was less pronounced than migration out of the tissue into the biomaterial. In a miniaturized model of preterm cell migration, PDGF-BB promoted migration of preterm amnion cells into the biomaterial. DISCUSSION AND CONCLUSION By using a novel miniaturized model of preterm tissue, we here successfully demonstrate that PDGF-BB can promote preterm FM cell migration of microtissues encapsulated in a three-dimensional environment.
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Affiliation(s)
- Flurina Famos
- Department of Obstetrics, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Eva Avilla-Royo
- Department of Obstetrics, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Ladina Vonzun
- Department of Obstetrics, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- The Zurich Center for Fetal Diagnosis and Therapy, Zurich, Switzerland
| | - Nicole Ochsenbein-Kölble
- Department of Obstetrics, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- The Zurich Center for Fetal Diagnosis and Therapy, Zurich, Switzerland
| | - Martin Ehrbar
- Department of Obstetrics, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- The Zurich Center for Fetal Diagnosis and Therapy, Zurich, Switzerland
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A Review on Damage and Rupture Modelling for Soft Tissues. Bioengineering (Basel) 2022; 9:bioengineering9010026. [PMID: 35049735 PMCID: PMC8773318 DOI: 10.3390/bioengineering9010026] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 11/16/2022] Open
Abstract
Computational modelling of damage and rupture of non-connective and connective soft tissues due to pathological and supra-physiological mechanisms is vital in the fundamental understanding of failures. Recent advancements in soft tissue damage models play an essential role in developing artificial tissues, medical devices/implants, and surgical intervention practices. The current article reviews the recently developed damage models and rupture models that considered the microstructure of the tissues. Earlier review works presented damage and rupture separately, wherein this work reviews both damage and rupture in soft tissues. Wherein the present article provides a detailed review of various models on the damage evolution and tear in soft tissues focusing on key conceptual ideas, advantages, limitations, and challenges. Some key challenges of damage and rupture models are outlined in the article, which helps extend the present damage and rupture models to various soft tissues.
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10
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Computational modeling in pregnancy biomechanics research. J Mech Behav Biomed Mater 2022; 128:105099. [DOI: 10.1016/j.jmbbm.2022.105099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 01/11/2022] [Accepted: 01/18/2022] [Indexed: 11/24/2022]
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Mhatre A, Shetty D, Shetty A, Dharmadhikari S, Wadkar P. Comparative evaluation of the physical properties of membranes for periodontal regeneration: An In vitro Study. ADVANCES IN HUMAN BIOLOGY 2022. [DOI: 10.4103/aihb.aihb_113_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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12
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Membrane curvature and connective fiber alignment in guinea pig round window membrane. Acta Biomater 2021; 136:343-362. [PMID: 34563725 DOI: 10.1016/j.actbio.2021.09.036] [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: 02/15/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 11/23/2022]
Abstract
The round window membrane (RWM) covers an opening between the perilymph fluid-filled inner ear space and the air-filled middle ear space. As the only non-osseous barrier between these two spaces, the RWM is an ideal candidate for aspiration of perilymph for diagnostics purposes and delivery of medication for treatment of inner ear disorders. Routine access across the RWM requires the development of new surgical tools whose design can only be optimized with a thorough understanding of the RWM's structure and properties. The RWM possesses a layer of collagen and elastic fibers so characterization of the distribution and orientation of these fibers is essential. Confocal and two-photon microscopy were conducted on intact RWMs in a guinea pig model to characterize the distribution of collagen and elastic fibers. The fibers were imaged via second-harmonic-generation, autofluorescence, and Rhodamine B staining. Quantitative analyses of both fiber orientation and geometrical properties of the RWM uncovered a significant correlation between mean fiber orientations and directions of zero curvature in some portions of the RWM, with an even more significant correlation between the mean fiber orientations and linear distance along the RWM in a direction approximately parallel to the cochlear axis. The measured mean fiber directions and dispersions can be incorporated into a generalized structure tensor for use in the development of continuum anisotropic mechanical constitutive models that in turn will enable optimization of surgical tools to access the cochlea. STATEMENT OF SIGNIFICANCE: The Round Window Membrane (RWM) is the only non-osseous barrier separating the middle and inner ear spaces, and thus is an ideal portal for medical access to the cochlea. An understanding of RWM structure and mechanical response is necessary to optimize the design of surgical tools for this purpose. The RWM geometry and the connective fiber orientation and dispersion are measured via confocal and 2-photon microscopy. A region of the RWM geometry is characterized as a hyperbolic paraboloid and another region as a tapered parabolic cylinder. Predominant fiber directions correlate well with directions of zero curvature in the hyperbolic paraboloid region. Overall fiber directions correlate well with position along a line approximately parallel to the central axis of the cochlea's spiral.
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13
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Leimert KB, Xu W, Princ MM, Chemtob S, Olson DM. Inflammatory Amplification: A Central Tenet of Uterine Transition for Labor. Front Cell Infect Microbiol 2021; 11:660983. [PMID: 34490133 PMCID: PMC8417473 DOI: 10.3389/fcimb.2021.660983] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 06/30/2021] [Indexed: 11/23/2022] Open
Abstract
In preparation for delivery, the uterus transitions from actively maintaining quiescence during pregnancy to an active parturient state. This transition occurs as a result of the accumulation of pro-inflammatory signals which are amplified by positive feedback interactions involving paracrine and autocrine signaling at the level of each intrauterine cell and tissue. The amplification events occur in parallel until they reach a certain threshold, ‘tipping the scale’ and contributing to processes of uterine activation and functional progesterone withdrawal. The described signaling interactions all occur upstream from the presentation of clinical labor symptoms. In this review, we will: 1) describe the different physiological processes involved in uterine transition for each intrauterine tissue; 2) compare and contrast the current models of labor initiation; 3) introduce innovative models for measuring paracrine inflammatory interactions; and 4) discuss the therapeutic value in identifying and targeting key players in this crucial event for preterm birth.
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Affiliation(s)
- Kelycia B Leimert
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada
| | - Wendy Xu
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada
| | - Magdalena M Princ
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada
| | - Sylvain Chemtob
- Department of Pediatrics, Ophthalmology and Pharmacology, CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - David M Olson
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada
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Amberg B, DeKoninck P, Kashyap A, Rodgers K, Zahra V, Hooper S, Crossley K, Hodges R. The effects of cold, dry and heated, humidified amniotic insufflation on sheep fetal membranes. Placenta 2021; 114:1-7. [PMID: 34418749 DOI: 10.1016/j.placenta.2021.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 07/16/2021] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Uterine distension with pressurised carbon dioxide (CO2) (amniotic insufflation) is used clinically to improve visibility during keyhole fetal surgery. However, there are concerns that amniotic insufflation with unconditioned (cold, dry) CO2 damages the fetal membranes which leads to post-operative preterm prelabour rupture of membranes (iatrogenic PPROM). We assessed whether heating and humidifying the insufflated CO2 could reduce fetal membrane damage in sheep. METHODS Thirteen pregnant ewes at 103-106 days gestation underwent amniotic insufflation with cold, dry (22 °C, 0-5% humidity, n = 6) or heated, humidified (40 °C, 95-100% humidity, n = 7) CO2 at 15 mmHg for 180 min. Twelve non-insufflated amniotic sacs acted as controls. Fetal membrane sections were collected after insufflation and analysed for molecular and histological markers of cell damage (caspase 3 and high mobility group box 1 [HMGB1]), inflammation (interleukin 1-alpha [IL1-alpha], IL8 and vascular cell adhesion molecule [VCAM]) and collagen weakening (matrix metalloprotease 9 [MMP9]). RESULTS Exposure to cold, dry CO2 increased mRNA levels of caspase 3, HMGB1, IL1-alpha, IL8, VCAM and MMP9 and increased amniotic epithelial caspase 3 and HMGB1 cell counts relative to controls. Exposure to heated, humidified CO2 also increased IL8 levels relative to controls however, HMGB1, IL1-alpha and VCAM mRNA levels and amniotic epithelial HMGB1 cell counts were significantly lower than the cold, dry group. DISCUSSION Amniotic insufflation with cold, dry CO2 damaged the amniotic epithelium and induced fetal membrane inflammation. Heated, humidified insufflation partially mitigated this damage and inflammation in sheep and may prove an important step in reducing the risk of iatrogenic PPROM following keyhole fetal surgery.
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Affiliation(s)
- Benjamin Amberg
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia; The Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Philip DeKoninck
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia; The Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia; Department of Obstetrics and Gynaecology, Erasmus MC-Sophia Children's Hospital, Rotterdam, the Netherlands
| | - Aidan Kashyap
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia; The Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Karyn Rodgers
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia; The Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Valarie Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia; The Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Stuart Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia; The Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Kelly Crossley
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia; The Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Ryan Hodges
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia; The Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia.
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15
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Weichert J, Sepulveda W, Gembicki M. Further insights into unusual acrania-exencephaly-anencephaly sequence caused by amniotic band – first trimester fetoscopic correlation with two- and three-dimensional ultrasound. CASE REPORTS IN PERINATAL MEDICINE 2021. [DOI: 10.1515/crpm-2021-0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Objectives
Antenatal detection of acrania-exencephaly-anencephaly (AEA) sequence beyond 10 completed weeks of gestation is usually straight-forward. An earlier detection and classification of the causative conditions prior to disaggregation of exposed dysplastic brain tissue remains challenging.
Case presentation
We present two- and three-dimensional ultrasound correlated with fetoscopic findings of an unusual type of neural tube defect at 11 gestational weeks caused by an amniotic constriction ring resulting in cystic degeneration of the developing skull.
Conclusions
By giving further illustrative insights into early defective brain development, this report confirms recent findings of an unusual subtype of acrania-exencephaly-anencephaly sequence suggesting early disruption of the developing brain, following an amniotic entrapment of the skull.
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Affiliation(s)
- Jan Weichert
- Department of Gynecology and Obstetrics , Division of Prenatal Medicine, University Hospital of Schleswig-Holstein, Campus Luebeck , Luebeck , Germany
| | - Waldo Sepulveda
- FETALMED – Maternal-Fetal Diagnostic Center , Santiago , Chile
| | - Michael Gembicki
- Department of Gynecology and Obstetrics , Division of Prenatal Medicine, University Hospital of Schleswig-Holstein, Campus Luebeck , Luebeck , Germany
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16
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Amberg BJ, Hodges RJ, Rodgers KA, Crossley KJ, Hooper SB, DeKoninck PLJ. Why Do the Fetal Membranes Rupture Early after Fetoscopy? A Review. Fetal Diagn Ther 2021; 48:493-503. [PMID: 34404043 DOI: 10.1159/000517151] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 05/03/2021] [Indexed: 11/19/2022]
Abstract
Iatrogenic preterm premature rupture of the fetal membranes (iPPROM) remains the Achilles' heel of keyhole fetal surgery (fetoscopy) despite significant efforts in preclinical models to develop new therapies. This limited success is partially due to incomplete understanding why the fetal membranes rupture early after fetoscopy and notable differences in membrane physiology between humans and domestic species. In this review, we summarize aspects of fetoscopy that may contribute to iPPROM, the previous efforts to develop new therapies, and limitations of preclinical models commonly used in fetal membrane research.
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Affiliation(s)
- Benjamin J Amberg
- The Department of Obstetrics and Gynaecology, School of Clinical Sciences, Monash University, Melbourne, Victoria, Australia, .,The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia,
| | - Ryan J Hodges
- The Department of Obstetrics and Gynaecology, School of Clinical Sciences, Monash University, Melbourne, Victoria, Australia.,The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - Karyn A Rodgers
- The Department of Obstetrics and Gynaecology, School of Clinical Sciences, Monash University, Melbourne, Victoria, Australia.,The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - Kelly J Crossley
- The Department of Obstetrics and Gynaecology, School of Clinical Sciences, Monash University, Melbourne, Victoria, Australia.,The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - Stuart B Hooper
- The Department of Obstetrics and Gynaecology, School of Clinical Sciences, Monash University, Melbourne, Victoria, Australia.,The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - Philip L J DeKoninck
- The Department of Obstetrics and Gynaecology, School of Clinical Sciences, Monash University, Melbourne, Victoria, Australia.,The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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17
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Bircher K, Merluzzi R, Wahlsten A, Spiess D, Simões-Wüst AP, Ochsenbein-Kölble N, Zimmermann R, Deprest J, Mazza E. Influence of osmolarity and hydration on the tear resistance of the human amniotic membrane. J Biomech 2019; 98:109419. [PMID: 31679754 DOI: 10.1016/j.jbiomech.2019.109419] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/15/2019] [Accepted: 10/13/2019] [Indexed: 12/20/2022]
Abstract
The amnion is considered to be the load-bearing part of the fetal membranes. We investigated the influence of osmolarity of the testing medium and hydration on its fracture toughness. Mode I fracture tests revealed that physiological variations in the bath osmolarity do not influence the tear resistance of amnion, while larger changes, i.e. from physiological saline solution to distilled water, lead to a significant reduction of the fracture toughness. Uniaxial tensile tests on collagen hydrogels confirmed the reduction in toughness, suggesting that lower bath osmolarity triggers changes in the failure properties of single collagen fibers. Prenatal surgeries, in particular fetoscopic procedures with partial amniotic carbon dioxide insufflation, might result in dehydration of the amnion. Dehydration induced a brittle behavior; however, subsequent rehydration for 15 min resulted in a similar tear resistance as for the fresh tissue.
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Affiliation(s)
- Kevin Bircher
- ETH Zurich, Institute for Mechanical Systems, 8092 Zurich, Switzerland
| | - Riccardo Merluzzi
- ETH Zurich, Institute for Mechanical Systems, 8092 Zurich, Switzerland
| | - Adam Wahlsten
- ETH Zurich, Institute for Mechanical Systems, 8092 Zurich, Switzerland
| | - Deborah Spiess
- University Hospital Zurich, Department of Obstetrics, 8091 Zurich, Switzerland
| | | | | | - Roland Zimmermann
- University Hospital Zurich, Department of Obstetrics, 8091 Zurich, Switzerland
| | - Jan Deprest
- University Hospitals Leuven, Department of Obstetrics and Gynecology, 3000 Leuven, Belgium; Institute of Women's Health, Research Department of Maternal Fetal Medicine, University College London, London, UK
| | - Edoardo Mazza
- ETH Zurich, Institute for Mechanical Systems, 8092 Zurich, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland.
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18
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Miller KS, Myers K, Oyen M. Bioengineering in women's health, volume 2: pregnancy—from implantation to parturition. Interface Focus 2019. [DOI: 10.1098/rsfs.2019.0081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
This special issue of
Interface Focus
is the second of two sets of articles on the topic of bioengineering in women's health. This second issue in the series focuses on pregnancy, a dynamic time in a women's life that involves dramatic physiologic changes within a relatively small timeframe. Pregnancy demands endurance and resilience of one's body and represents a critical component of women's health research. The health of an individual leading up to, during and after pregnancy is paramount for reproductive health and the lifelong health of offspring. The articles in this issue explore physiological events that support reproduction spanning from embryo implantation, through gestation, to delivery and parturition. Specifically, the articles highlight essential developments in placenta, fetal membranes, cervix, pelvic floor and anthropometry research. The featured bioengineering disciplines deployed to study such complex biological processes are diverse, with articles detailing the latest advancements in computational modelling at various biological length-scales, biomaterial design, material modelling, non-invasive diagnostic techniques, microfluidic devices and experimental mechanics. This second issue continues the first in this series, on the physiology of the non-pregnant woman.
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Affiliation(s)
- Kristin S. Miller
- Biomedical Engineering, Tulane University, 500 Lindy Boggs Center, New Orleans, LA 70118, USA
| | - Kristin Myers
- Mechanical Engineering, Columbia University, New York, NY 10025, USA
| | - Michelle Oyen
- Department of Engineering, East Carolina University, Greenville, NC, USA
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