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Mekonnen TT, Ambekar YS, Zevallos-Delgado C, Nair A, Zvietcovich F, Zarkoob H, Singh M, Lim YW, Ferrer M, Aglyamov SR, Scarcelli G, Song MJ, Larin KV. Dual optical elastography detects TGF - β -induced alterations in the biomechanical properties of skin scaffolds. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:095002. [PMID: 39295639 PMCID: PMC11409821 DOI: 10.1117/1.jbo.29.9.095002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Revised: 08/27/2024] [Accepted: 09/03/2024] [Indexed: 09/21/2024]
Abstract
Significance The skin's mechanical properties are tightly regulated. Various pathologies can affect skin stiffness, and understanding these changes is a focus in tissue engineering. Ex vivo skin scaffolds are a robust platform for evaluating the effects of various genetic and molecular interactions on the skin. Transforming growth factor-beta ( TGF - β ) is a critical signaling molecule in the skin that can regulate the amount of collagen and elastin in the skin and, consequently, its mechanical properties. Aim This study investigates the biomechanical properties of bio-engineered skin scaffolds, focusing on the influence of TGF - β , a signaling molecule with diverse cellular functions. Approach The TGF - β receptor I inhibitor, galunisertib, was employed to assess the mechanical changes resulting from dysregulation of TGF - β . Skin scaffold samples, grouped into three categories (control, TGF - β -treated, and TGF - β + galunisertib-treated), were prepared in two distinct culture media-one with aprotinin (AP) and another without. Two optical elastography techniques, namely wave-based optical coherence elastography (OCE) and Brillouin microscopy, were utilized to quantify the biomechanical properties of the tissues. Results Results showed significantly higher wave speed (with AP, p < 0.001 ; without AP, p < 0.001 ) and Brillouin frequency shift (with AP, p < 0.001 ; without AP, p = 0.01 ) in TGF - β -treated group compared with the control group. The difference in wave speed between the control and TGF - β + galunisertib with ( p = 0.10 ) and without AP ( p = 0.36 ) was not significant. Moreover, the TGF - β + galunisertib-treated group exhibited lower wave speed without and with AP and reduced Brillouin frequency shift than the TGF - β -treated group without AP, further strengthening the potential role of TGF - β in regulating the mechanical properties of the samples. Conclusions These findings offer valuable insights into TGF - β -induced biomechanical alterations in bio-engineered skin scaffolds, highlighting the potential of OCE and Brillouin microscopy in the development of targeted therapies in conditions involving abnormal tissue remodeling and fibrosis.
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Affiliation(s)
- Taye T. Mekonnen
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
- University of Sydney, Department of Mechanical Engineering, Sydney, New South Wales, Australia
| | - Yogeshwari S. Ambekar
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
| | | | - Achuth Nair
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Fernando Zvietcovich
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
- Pontificia Universidad Catolica del Peru, Department of Engineering, Lima, Peru
| | - Hoda Zarkoob
- National Institutes of Health, National Center for Advancing Translational Sciences, Rockville, Maryland, United States
| | - Manmohan Singh
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Yi Wei Lim
- National Institutes of Health, National Center for Advancing Translational Sciences, Rockville, Maryland, United States
| | - Marc Ferrer
- National Institutes of Health, National Center for Advancing Translational Sciences, Rockville, Maryland, United States
| | - Salavat R. Aglyamov
- University of Houston, Department of Mechanical Engineering, Houston, Texas, United States
| | - Giuliano Scarcelli
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
| | - Min Jae Song
- National Institutes of Health, National Center for Advancing Translational Sciences, Rockville, Maryland, United States
| | - Kirill V. Larin
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
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2
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Zheng Z, Meng Sua Y, Zhu S, Rehain P, Huang YP. Non-contact elasticity contrast imaging using photon counting. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:076003. [PMID: 38989529 PMCID: PMC11234449 DOI: 10.1117/1.jbo.29.7.076003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 05/17/2024] [Accepted: 05/17/2024] [Indexed: 07/12/2024]
Abstract
Significance Tissues' biomechanical properties, such as elasticity, are related to tissue health. Optical coherence elastography produces images of tissues based on their elasticity, but its performance is constrained by the laser power used, working distance, and excitation methods. Aim We develop a new method to reconstruct the elasticity contrast image over a long working distance, with only low-intensity illumination, and by non-contact acoustic wave excitation. Approach We combine single-photon vibrometry and quantum parametric mode sorting (QPMS) to measure the oscillating backscattered signals at a single-photon level and derive the phantoms' relative elasticity. Results We test our system on tissue-mimicking phantoms consisting of contrast sections with different concentrations and thus stiffness. Our results show that as the driving acoustic frequency is swept, the phantoms' vibrational responses are mapped onto the photon-counting histograms from which their mechanical properties-including elasticity-can be derived. Through lateral and longitudinal laser scanning at a fixed frequency, a contrast image based on samples' elasticity can be reliably reconstructed upon photon level signals. Conclusions We demonstrated the reliability of QPMS-based elasticity contrast imaging of agar phantoms in a long working distance, low-intensity environment. This technique has the potential for in-depth images of real biological tissue and provides a new approach to elastography research and applications.
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Affiliation(s)
- Zipei Zheng
- Stevens Institute of Technology, Center for Quantum Science and Engineering, Department of Physics, Hoboken, New Jersey, United States
| | - Yong Meng Sua
- Stevens Institute of Technology, Center for Quantum Science and Engineering, Department of Physics, Hoboken, New Jersey, United States
| | - Shenyu Zhu
- Stevens Institute of Technology, Center for Quantum Science and Engineering, Department of Physics, Hoboken, New Jersey, United States
| | - Patrick Rehain
- Stevens Institute of Technology, Center for Quantum Science and Engineering, Department of Physics, Hoboken, New Jersey, United States
| | - Yu-Ping Huang
- Stevens Institute of Technology, Center for Quantum Science and Engineering, Department of Physics, Hoboken, New Jersey, United States
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3
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Burhan S, Detrez N, Rewerts K, Strenge P, Buschschlüter S, Kren J, Hagel C, Bonsanto MM, Brinkmann R, Huber R. Phase unwrapping for MHz optical coherence elastography and application to brain tumor tissue. BIOMEDICAL OPTICS EXPRESS 2024; 15:1038-1058. [PMID: 38404346 PMCID: PMC10890849 DOI: 10.1364/boe.510020] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/15/2023] [Accepted: 12/17/2023] [Indexed: 02/27/2024]
Abstract
During neuro-oncologic surgery, phase-sensitive optical coherence elastography (OCE) can be valuable for distinguishing between healthy and diseased tissue. However, the phase unwrapping process required to retrieve the original phase signal is a challenging and critical task. To address this issue, we demonstrate a one-dimensional unwrapping algorithm that recovers the phase signal from a 3.2 MHz OCE system. With a processing time of approximately 0.11 s per frame on the GPU, multiple 2π wraps are detected and corrected. By utilizing this approach, exact and reproducible information on tissue deformation can be obtained with pixel accuracy over the entire acquisition time. Measurements of brain tumor-mimicking phantoms and human ex vivo brain tumor samples verified the algorithm's reliability. The tissue samples were subjected to a 200 ms short air pulse. A correlation with histological findings confirmed the algorithm's dependability.
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Affiliation(s)
- Sazgar Burhan
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Nicolas Detrez
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Katharina Rewerts
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Paul Strenge
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | | | - Jessica Kren
- Klinik für Neurochirurgie, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Christian Hagel
- Institut für Neuropathologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20251 Hamburg, Germany
| | - Matteo Mario Bonsanto
- Institut für Neuropathologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20251 Hamburg, Germany
| | - Ralf Brinkmann
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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Salimi M, Roshanfar M, Tabatabaei N, Mosadegh B. Machine Learning-Assisted Short-Wave InfraRed (SWIR) Techniques for Biomedical Applications: Towards Personalized Medicine. J Pers Med 2023; 14:33. [PMID: 38248734 PMCID: PMC10817559 DOI: 10.3390/jpm14010033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/08/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
Personalized medicine transforms healthcare by adapting interventions to individuals' unique genetic, molecular, and clinical profiles. To maximize diagnostic and/or therapeutic efficacy, personalized medicine requires advanced imaging devices and sensors for accurate assessment and monitoring of individual patient conditions or responses to therapeutics. In the field of biomedical optics, short-wave infrared (SWIR) techniques offer an array of capabilities that hold promise to significantly enhance diagnostics, imaging, and therapeutic interventions. SWIR techniques provide in vivo information, which was previously inaccessible, by making use of its capacity to penetrate biological tissues with reduced attenuation and enable researchers and clinicians to delve deeper into anatomical structures, physiological processes, and molecular interactions. Combining SWIR techniques with machine learning (ML), which is a powerful tool for analyzing information, holds the potential to provide unprecedented accuracy for disease detection, precision in treatment guidance, and correlations of complex biological features, opening the way for the data-driven personalized medicine field. Despite numerous biomedical demonstrations that utilize cutting-edge SWIR techniques, the clinical potential of this approach has remained significantly underexplored. This paper demonstrates how the synergy between SWIR imaging and ML is reshaping biomedical research and clinical applications. As the paper showcases the growing significance of SWIR imaging techniques that are empowered by ML, it calls for continued collaboration between researchers, engineers, and clinicians to boost the translation of this technology into clinics, ultimately bridging the gap between cutting-edge technology and its potential for personalized medicine.
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Affiliation(s)
| | - Majid Roshanfar
- Department of Mechanical Engineering, Concordia University, Montreal, QC H3G 1M8, Canada;
| | - Nima Tabatabaei
- Department of Mechanical Engineering, York University, Toronto, ON M3J 1P3, Canada;
| | - Bobak Mosadegh
- Dalio Institute of Cardiovascular Imaging, Department of Radiology, Weill Cornell Medicine, New York, NY 10021, USA
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5
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Desai R, Chawla H, Larin K, Assassi S. Methods for objective assessment of skin involvement in systemic sclerosis. Curr Opin Rheumatol 2023; 35:301-308. [PMID: 37605869 PMCID: PMC11015902 DOI: 10.1097/bor.0000000000000968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
PURPOSE OF REVIEW Skin fibrosis is the most prominent disease manifestation of systemic sclerosis (SSc). Although the treatment for other SSc manifestations has expanded over the years, there is limited progress in identifying effective treatment options for SSc skin involvement. This is in part due to limitations in the utilized outcome measures for assessment of skin fibrosis. This review focuses on different emerging assessment tools for SSc skin involvement and their potential use for clinical care and multicenter trials. RECENT FINDINGS Durometer and other device-based methodologies requiring application of direct pressure to the affected skin have been studied in SSc. However, there are concerns that the required application of pressure might be a source of variability. Ultrasound-based methods have been compared with modified Rodnan Skin Score in several studies, indicating acceptable construct validity. However, few studies have examined their criterion validity by providing comparisons to skin histology. Optical coherence-based methods show promising preliminary results for simultaneous assessment of skin fibrosis and vasculopathy. Further standardization and validation (including comparison to skin histology) of these promising novel assessment tools in large, longitudinal SSc cohort studies are needed to establish them as clinically useful outcome measures with acceptable sensitivity to change. SUMMARY Recent advances in imaging techniques provide a promising opportunity for development of a valid and reliable assessment tool for quantification of SSc skin fibrosis, which can pave the way for approval of effective treatment options for this high burden disease manifestation.
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Affiliation(s)
- Ruhani Desai
- Division of Rheumatology, The University of Texas Health Science Center at Houston, TX, USA
| | - Harshdeep Chawla
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Kirill Larin
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Shervin Assassi
- Division of Rheumatology, The University of Texas Health Science Center at Houston, TX, USA
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6
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Hatami M, Nevozhay D, Singh M, Schill A, Boerner P, Aglyamov S, Sokolov K, Larin KV. Nanobomb optical coherence elastography in multilayered phantoms. BIOMEDICAL OPTICS EXPRESS 2023; 14:5670-5681. [PMID: 38021113 PMCID: PMC10659790 DOI: 10.1364/boe.502576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/23/2023] [Accepted: 10/03/2023] [Indexed: 12/01/2023]
Abstract
Many tissues are composed of layered structures, and a better understanding of the changes in the layered tissue biomechanics can enable advanced guidance and monitoring of therapy. The advent of elastography using longitudinally propagating shear waves (LSWs) has created the prospect of a high-resolution assessment of depth-dependent tissue elasticity. Laser activation of liquid-to-gas phase transition of dye-loaded perfluorocarbon (PFC) nanodroplets (a.k.a., nanobombs) can produce highly localized LSWs. This study aims to leverage the potential of photoactivation of nanobombs to incudce LSWs with very high-frequency content in wave-based optical coherence elastography (OCE) to estimate the elasticity gradient with high resolution. In this work, we used multilayered tissue-mimicking phantoms to demonstrate that highly localized nanobomb (NB)-induced LSWs can discriminate depth-wise tissue elasticity gradients. The results show that the NB-induced LSWs rapidly change speed when transitioning between layers with different mechanical properties, resulting in an elasticity resolution of ∼65 µm. These results show promise for characterizing the elasticity of multilayer tissue with a fine resolution.
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Affiliation(s)
- Maryam Hatami
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204, USA
| | - Dmitry Nevozhay
- Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204, USA
| | - Alexander Schill
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204, USA
| | - Paul Boerner
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204, USA
| | - Salavat Aglyamov
- Department of Mechanical Engineering, University of Houston, Houston, Texas 77204, USA
| | - Konstantin Sokolov
- Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Department of Bioengineering, Rice University, Houston, Texas 77030, USA
| | - Kirill V Larin
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204, USA
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7
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Mekonnen T, Schill AW, Zevallos-Delgado C, Singh M, Aglyamov SR, Larin KV. Reverberant optical coherence elastography using multifocal acoustic radiation force. OPTICS LETTERS 2023; 48:2773-2776. [PMID: 37262207 DOI: 10.1364/ol.482201] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 04/15/2023] [Indexed: 06/03/2023]
Abstract
In this study, we introduce a multifocal acoustic radiation force source that combines an ultrasound transducer and a 3D-printed acoustic lens for application in reverberant optical coherence elastography (Rev-OCE). An array of plano-concave acoustic lenses, each with an 11.8 mm aperture diameter, were used to spatially distribute the acoustic energy generated by a 1 MHz planar ultrasound transducer, producing multiple focal spots on a target plane. These focal spots generate reverberant shear wave fields detected by the optical coherence tomography (OCT) system. The effectiveness of the multifocal Rev-OCE system in probing mechanical properties with high resolution is demonstrated in layered gelatin phantoms.
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8
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Mekonnen T, Zevallos-Delgado C, Zhang H, Singh M, Aglyamov SR, Larin KV. The lens capsule significantly affects the viscoelastic properties of the lens as quantified by optical coherence elastography. Front Bioeng Biotechnol 2023; 11:1134086. [PMID: 36970614 PMCID: PMC10034121 DOI: 10.3389/fbioe.2023.1134086] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 02/21/2023] [Indexed: 03/11/2023] Open
Abstract
The crystalline lens is a transparent, biconvex structure that has its curvature and refractive power modulated to focus light onto the retina. This intrinsic morphological adjustment of the lens to fulfill changing visual demands is achieved by the coordinated interaction between the lens and its suspension system, which includes the lens capsule. Thus, characterizing the influence of the lens capsule on the whole lens’s biomechanical properties is important for understanding the physiological process of accommodation and early diagnosis and treatment of lenticular diseases. In this study, we assessed the viscoelastic properties of the lens using phase-sensitive optical coherence elastography (PhS-OCE) coupled with acoustic radiation force (ARF) excitation. The elastic wave propagation induced by ARF excitation, which was focused on the surface of the lens, was tracked with phase-sensitive optical coherence tomography. Experiments were conducted on eight freshly excised porcine lenses before and after the capsular bag was dissected away. Results showed that the group velocity of the surface elastic wave, V, in the lens with the capsule intact (V=2.55±0.23 m/s) was significantly higher (p < 0.001) than after the capsule was removed (V=1.19±0.25 m/s). Similarly, the viscoelastic assessment using a model that utilizes the dispersion of a surface wave showed that both Young’s modulus, E, and shear viscosity coefficient, η, of the encapsulated lens (E=8.14±1.10 kPa,η=0.89±0.093 Pa∙s) were significantly higher than that of the decapsulated lens (E=3.10±0.43 kPa,η=0.28±0.021 Pa∙s). These findings, together with the geometrical change upon removal of the capsule, indicate that the capsule plays a critical role in determining the viscoelastic properties of the crystalline lens.
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Affiliation(s)
- Taye Mekonnen
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | | | - Hongqiu Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Salavat R. Aglyamov
- Department of Mechanical Engineering, University of Houston, Houston, TX, United States
| | - Kirill V. Larin
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
- *Correspondence: Kirill V. Larin,
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9
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Zaitsev VY, Sovetsky AA, Matveyev AL, Matveev LA, Shabanov D, Salamatova VY, Karavaikin PA, Vassilevski YV. Application of compression optical coherence elastography for characterization of human pericardium: A pilot study. JOURNAL OF BIOPHOTONICS 2023; 16:e202200253. [PMID: 36397665 DOI: 10.1002/jbio.202200253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/23/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
The recent impressive progress in Compression Optical Coherence Elastography (C-OCE) demonstrated diverse biomedical applications, comprising ophthalmology, oncology, etc. High resolution of C-OCE enables spatially resolved characterization of elasticity of rather thin (thickness < 1 mm) samples, which previously was impossible. Besides Young's modulus, C-OCE enables obtaining of nonlinear stress-strain dependences for various tissues. Here, we report the first application of C-OCE to nondestructively characterize biomechanics of human pericardium, for which data of conventional tensile tests are very limited and controversial. C-OCE revealed pronounced differences among differently prepared pericardium samples. Ample understanding of the influence of chemo-mechanical treatment on pericardium biomechanics is very important because of rapidly growing usage of own patients' pericardium for replacement of aortic valve leaflets in cardio-surgery. The figure demonstrates differences in the tangent Young's modulus after glutaraldehyde-induced cross-linking for two pericardium samples. One sample was over-stretched during the preparation, which caused some damage to the tissue.
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Affiliation(s)
- Vladimir Y Zaitsev
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Alexander A Sovetsky
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Alexander L Matveyev
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Lev A Matveev
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Dmitry Shabanov
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Victoria Y Salamatova
- Sechenov University, Moscow, Russia
- Sirius University of Science and Technology, Sochi, Russia
| | | | - Yuri V Vassilevski
- Sechenov University, Moscow, Russia
- Sirius University of Science and Technology, Sochi, Russia
- Marchuk Institute of Numerical Mathematics, Russian Academy of Sciences, Moscow, Russia
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10
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Lin X, Mekonnen T, Verma S, Zevallos-Delgado C, Singh M, Aglyamov SR, Gesteira TF, Larin KV, Coulson-Thomas VJ. Hyaluronan Modulates the Biomechanical Properties of the Cornea. Invest Ophthalmol Vis Sci 2022; 63:6. [PMID: 36478198 PMCID: PMC9733656 DOI: 10.1167/iovs.63.13.6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose Hyaluronan (HA) is a major constituent of the extracellular matrix (ECM) that has high viscosity and is essential for maintaining tissue hydration. In the cornea, HA is enriched in the limbal region and is a key component of the limbal epithelial stem cell niche. HA is upregulated after injury participating in the formation of the provisional matrix, and has a key role in regulating the wound healing process. This study investigated whether changes in the distribution of HA before and after injury affects the biomechanical properties of the cornea in vivo. Methods Corneas of wild-type (wt) mice and mice lacking enzymes involved in the biosynthesis of HA were analyzed before, immediately after, and 7 and 14 days after a corneal alkali burn (AB). The corneas were evaluated using both a ring light and fluorescein stain by in vivo confocal microscopy, optical coherence elastography (OCE), and immunostaining of corneal whole mounts. Results Our results show that wt mice and mice lacking HA synthase (Has)1 and 3 present an increase in corneal stiffness 7 and 14 days after AB without a significant increase in HA expression and absence of scarring at 14 days after AB. In contrast, mice lacking Has2 present a significant decrease in corneal stiffness, with a significant increase in HA expression and scarring at 14 days after AB. Conclusions Our findings show that the mechanical properties of the cornea are significantly modulated by changes in HA distribution following alkali burn.
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Affiliation(s)
- Xiao Lin
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Taye Mekonnen
- Department of Biomedical Engineering, University of Houston, Houston, Texas, United States
| | - Sudhir Verma
- College of Optometry, University of Houston, Houston, Texas, United States,Department of Zoology, Deen Dayal Upadhyaya College, University of Delhi, Delhi, India
| | | | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, Houston, Texas, United States
| | - Salavat R. Aglyamov
- Department of Mechanical Engineering, University of Houston, Houston, Texas, United States
| | - Tarsis F. Gesteira
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Kirill V. Larin
- Department of Biomedical Engineering, University of Houston, Houston, Texas, United States
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11
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Nair A, Ambekar YS, Zevallos-Delgado C, Mekonnen T, Sun M, Zvietcovich F, Singh M, Aglyamov S, Koch M, Scarcelli G, Espana EM, Larin KV. Multiple Optical Elastography Techniques Reveal the Regulation of Corneal Stiffness by Collagen XII. Invest Ophthalmol Vis Sci 2022; 63:24. [PMID: 36383352 PMCID: PMC9680591 DOI: 10.1167/iovs.63.12.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 10/19/2022] [Indexed: 11/17/2022] Open
Abstract
Purpose Collagen XII plays a role in regulating the structure and mechanical properties of the cornea. In this work, several optical elastography techniques were used to investigate the effect of collagen XII deficiency on the stiffness of the murine cornea. Methods A three-prong optical elastography approach was used to investigate the mechanical properties of the cornea. Brillouin microscopy, air-coupled ultrasonic optical coherence elastography (OCE) and heartbeat OCE were used to assess the mechanical properties of wild type (WT) and collagen XII-deficient (Col12a1-/-) murine corneas. The Brillouin frequency shift, elastic wave speed, and compressive strain were all measured as a function of intraocular pressure (IOP). Results All three optical elastography modalities measured a significantly decreased stiffness in the Col12a1-/- compared to the WT (P < 0.01 for all three modalities). The optical coherence elastography techniques showed that mean stiffness increased as a function of IOP; however, Brillouin microscopy showed no discernable trend in Brillouin frequency shift as a function of IOP. Conclusions Our approach suggests that the absence of collagen XII significantly softens the cornea. Although both optical coherence elastography techniques showed an expected increase in corneal stiffness as a function of IOP, Brillouin microscopy did not show such a relationship, suggesting that the Brillouin longitudinal modulus may not be affected by changes in IOP. Future work will focus on multimodal biomechanical models, evaluating the effects of other collagen types on corneal stiffness, and in vivo measurements.
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Affiliation(s)
- Achuth Nair
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Yogeshwari S. Ambekar
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | | | - Taye Mekonnen
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Mei Sun
- Cornea and External Disease, Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Fernando Zvietcovich
- Department of Engineering, Pontificia Universidad Catolica del Peru, San Miguel, Lima, Peru
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Salavat Aglyamov
- Department of Mechanical Engineering, University of Houston, Houston, TX, United States
| | - Manuel Koch
- Institute for Dental Research and Oral Musculoskeletal Biology, Center for Molecular Medicine Cologne, and Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Giuliano Scarcelli
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States
| | - Edgar M. Espana
- Cornea and External Disease, Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Kirill V. Larin
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States
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