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Son YJ, Keum C, Kim M, Jeong G, Jin S, Hwang HW, Kim H, Lee K, Jeon H, Kim H, Pahk KJ, Jang HW, Sun JY, Han HS, Lee KH, Ok MR, Kim YC, Jeong Y. Selective Cell-Cell Adhesion Regulation via Cyclic Mechanical Deformation Induced by Ultrafast Nanovibrations. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37751467 DOI: 10.1021/acsami.3c08941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
The adoption of dynamic mechanomodulation to regulate cellular behavior is an alternative to the use of chemical drugs, allowing spatiotemporal control. However, cell-selective targeting of mechanical stimuli is challenging due to the lack of strategies with which to convert macroscopic mechanical movements to different cellular responses. Here, we designed a nanoscale vibrating surface that controls cell behavior via selective repetitive cell deformation based on a poroelastic cell model. The vibrating indentations induce repetitive water redistribution in the cells with water redistribution rates faster than the vibrating rate; however, in the opposite case, cells perceive the vibrations as a one-time stimulus. The selective regulation of cell-cell adhesion through adjusting the frequency of nanovibration was demonstrated by suppression of cadherin expression in smooth muscle cells (fast water redistribution rate) with no change in vascular endothelial cells (slow water redistribution rate). This technique may provide a new strategy for cell-type-specific mechanical stimulation.
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Affiliation(s)
- Young Ju Son
- Center for Biomaterials, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Changjoon Keum
- Center for Advanced Biomolecular Recognition, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Minsoo Kim
- Center for Advanced Biomolecular Recognition, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Department of Chemistry, Hanyang University, Seoul 04763, Republic of Korea
| | - Goeen Jeong
- Center for Biomaterials, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Soyeong Jin
- Center for Advanced Biomolecular Recognition, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Department of Chemistry, Hanyang University, Seoul 04763, Republic of Korea
| | - Hae Won Hwang
- Center for Biomaterials, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyewon Kim
- Center for Biomaterials, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Kyungwoo Lee
- Center for Biomaterials, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hojeong Jeon
- Center for Biomaterials, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea
| | - Hojun Kim
- Center for Advanced Biomolecular Recognition, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
| | - Ki Joo Pahk
- Department of Biomedical Engineering, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Ho Won Jang
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Jeong-Yun Sun
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyung-Seop Han
- Center for Biomaterials, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
| | - Kwan Hyi Lee
- Center for Advanced Biomolecular Recognition, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
| | - Myoung-Ryul Ok
- Center for Biomaterials, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
| | - Yu-Chan Kim
- Center for Biomaterials, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
| | - Youngdo Jeong
- Center for Advanced Biomolecular Recognition, Biomedical Research Division, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Department of HY-KIST Bio-convergence, Hanyang University, Seoul 04763, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
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Gupta D, Savva J, Li X, Chandler JH, Shelton RM, Scheven BA, Mulvana H, Valdastri P, Lucas M, Walmsley AD. Traditional Multiwell Plates and Petri Dishes Limit the Evaluation of the Effects of Ultrasound on Cells In Vitro. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:1745-1761. [PMID: 35760602 DOI: 10.1016/j.ultrasmedbio.2022.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 04/29/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
Ultrasound accelerates healing in fractured bone; however, the mechanisms responsible are poorly understood. Experimental setups and ultrasound exposures vary or are not adequately characterized across studies, resulting in inter-study variation and difficulty in concluding biological effects. This study investigated experimental variability introduced through the cell culture platform used. Continuous wave ultrasound (45 kHz; 10, 25 or 75 mW/cm2, 5 min/d) was applied, using a Duoson device, to Saos-2 cells seeded in multiwell plates or Petri dishes. Pressure field and vibration quantification and finite-element modelling suggested formation of complex interference patterns, resulting in localized displacement and velocity gradients, more pronounced in multiwell plates. Cell experiments revealed lower metabolic activities in both culture platforms at higher ultrasound intensities and absence of mineralization in certain regions of multiwell plates but not in Petri dishes. Thus, the same transducer produced variable results in different cell culture platforms. Analysis on Petri dishes further revealed that higher intensities reduced vinculin expression and distorted cell morphology, while causing mitochondrial and endoplasmic reticulum damage and accumulation of cells in sub-G1 phase, leading to cell death. More defined experimental setups and reproducible ultrasound exposure systems are required to study the real effect of ultrasound on cells for development of effective ultrasound-based therapies not just limited to bone repair and regeneration.
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Affiliation(s)
- Dhanak Gupta
- School of Dentistry, University of Birmingham, Birmingham, UK.
| | - Jill Savva
- Centre for Medical & Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow, Glasgow, UK
| | - Xuan Li
- Centre for Medical & Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow, Glasgow, UK
| | - James H Chandler
- Science and Technology of Robotics in Medicine (STORM) Laboratory UK, School of Electronic and Electrical Engineering, University of Leeds, Leeds, UK
| | | | - Ben A Scheven
- School of Dentistry, University of Birmingham, Birmingham, UK
| | - Helen Mulvana
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
| | - Pietro Valdastri
- Science and Technology of Robotics in Medicine (STORM) Laboratory UK, School of Electronic and Electrical Engineering, University of Leeds, Leeds, UK
| | - Margaret Lucas
- Centre for Medical & Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow, Glasgow, UK
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Machado P, Li J, Blackman R, Liu JB, Kepler CK, Fang T, Muratore R, Winder JH, Winder AA, Forsberg F. Comparison Between Clinically Available Low-Intensity Pulsed Ultrasound (LIPUS) and a Novel Bimodal Acoustic Signal System for Accelerating Fracture Healing. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:629-636. [PMID: 34822327 DOI: 10.1109/tuffc.2021.3130554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Low-intensity pulsed ultrasound (LIPUS) accelerates fracture healing by stimulating the production of bone callus and the mineralization process. This study compared a novel bimodal acoustic signal (BMAS) device for bone fracture healing to a clinical LIPUS system (EXOGEN; Bioventus, Durham, NC, USA). Thirty rabbits underwent a bilateral fibular osteotomy. Each rabbits' legs were randomized to receive 20-min treatment daily for 18 days with BMAS or LIPUS. The latter utilizes a longitudinal ultrasonic mode only, while the former employs ultrasound-induced shear stress to promote bone formation. Power Doppler imaging (PDI) was acquired days 0, 2, 4, 7, 11, 14, and 18 post-surgery to monitor treatment response and quantified off-line. X-rays were acquired to evaluate fractures on days 0, 14, 18, and 21. Seventeen rabbits completed the study and were euthanized day 21 post-surgery. The fibulae were analyzed to determine maximum torque, initial torsional stiffness, and angular displacement at failure. ANOVAs and paired t-tests were used to compare pair-wise outcome variables for the two treatment modes on a per rabbit basis. The BMAS system induced better fracture healing with greater stiffness (BMAS 0.21 ± 0.19 versus LIPUS 0.16 ± 0.19 [Formula: see text]cm/°, p = 0.050 ) and maximum torque (BMAS 7.84 ± 5.55 versus LIPUS 6.26 ± 3.46 [Formula: see text]cm, p = 0.022 ) than the LIPUS system. Quantitative PDI assessments showed a higher amount of vascularity with LIPUS than BMAS on days 4 and 18 ( ). In conclusion, the novel BMAS technique achieved better bone fracture healing response than the current Food and Drug Administration (FDA)-approved LIPUS system.
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Presas A, Valentin D, Deering J, Kampschulte M, Yu B, Grandfield K, Mele E, Biehl C, Krombach GA, Heiss C, Bosbach WA. Resonance vibration interventions in the femur: Experimental-numerical modelling approaches. J Mech Behav Biomed Mater 2021; 124:104850. [PMID: 34607300 DOI: 10.1016/j.jmbbm.2021.104850] [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: 04/21/2021] [Revised: 09/14/2021] [Accepted: 09/18/2021] [Indexed: 10/20/2022]
Abstract
MOTIVE External vibration excitation might be key to many novel non-surgical interventions for pathologies in the musculoskeletal system and in other parts of the human organism. Lack of understanding about vibration patterns, their controllability, and reproducibility are three limitations of ongoing research. This study establishes a bovine vibration model and animal model replacements for future research. METHODS We used biological samples (n=5) and one polyurethane sample of the bovine femur. Mechanical resonance was measured experimentally and analysed numerically by finite element method. MAIN RESULTS The experiments obtained 5 distinct mode shapes for the biological sample set, with standard deviation < 7.5%. Finite element analysis of the biological samples can replicate experimental mode shape deflection. The use of polyurethane changes resonance character but results are also good approximations of the biological samples. CONCLUSIONS A model of the bovine femur with consistent resonance behaviour is presented with alternatives (polyurethane and finite element analysis) that can serve in reducing the number of necessary biological samples. Future work will be to adapt results to human anatomy. Of clinical interest will be to influence bone pathologies such as post-surgical non-union, or bone functionality as part of haematopoiesis and endocrine secretion.
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Affiliation(s)
- Alexandre Presas
- Center for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Spain
| | - David Valentin
- Center for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Spain
| | - Joseph Deering
- Department of Materials Science and Engineering, McMaster University, Hamilton, ON, Canada
| | - Marian Kampschulte
- Experimental Radiology, Justus Liebig University of Giessen, Germany; Department of Diagnostic and Interventional, and Paediatric Radiology, University Hospital of Giessen, Germany
| | - Bosco Yu
- Department of Materials Science and Engineering, McMaster University, Hamilton, ON, Canada
| | - Kathryn Grandfield
- Department of Materials Science and Engineering, McMaster University, Hamilton, ON, Canada; School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada
| | - Elisa Mele
- Materials Department, Loughborough University, Loughborough, UK
| | - Christoph Biehl
- Experimental Trauma Surgery, Justus Liebig University of Giessen, Germany; Department of Trauma, Hand and Reconstructive Surgery, University Hospital of Giessen, Germany
| | - Gabriele A Krombach
- Experimental Radiology, Justus Liebig University of Giessen, Germany; Department of Diagnostic and Interventional, and Paediatric Radiology, University Hospital of Giessen, Germany
| | - Christian Heiss
- Experimental Trauma Surgery, Justus Liebig University of Giessen, Germany; Department of Trauma, Hand and Reconstructive Surgery, University Hospital of Giessen, Germany
| | - Wolfram A Bosbach
- Experimental Trauma Surgery, Justus Liebig University of Giessen, Germany; Department of Trauma, Hand and Reconstructive Surgery, University Hospital of Giessen, Germany.
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Giantulli S, Tortorella E, Brasili F, Scarpa S, Cerroni B, Paradossi G, Bedini A, Morrone S, Silvestri I, Domenici F. Effect of 1-MHz ultrasound on the proinflammatory interleukin-6 secretion in human keratinocytes. Sci Rep 2021; 11:19033. [PMID: 34561481 PMCID: PMC8463532 DOI: 10.1038/s41598-021-98141-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 08/02/2021] [Indexed: 02/08/2023] Open
Abstract
Keratinocytes, the main cell type of the skin, are one of the most exposed cells to environmental factors, providing a first defence barrier for the host and actively participating in immune response. In fact, keratinocytes express pattern recognition receptors that interact with pathogen associated molecular patterns and damage associated molecular patterns, leading to the production of cytokines and chemokines, including interleukin (IL)-6. Herein, we investigated whether mechanical energy transported by low intensity ultrasound (US) could generate a mechanical stress able to induce the release of inflammatory cytokine such IL-6 in the human keratinocyte cell line, HaCaT. The extensive clinical application of US in both diagnosis and therapy suggests the need to better understand the related biological effects. Our results point out that US promotes the overexpression and secretion of IL-6, associated with the activation of nuclear factor-κB (NF-κB). Furthermore, we observed a reduced cell viability dependent on exposure parameters together with alterations in membrane permeability, paving the way for further investigating the molecular mechanisms related to US exposure.
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Affiliation(s)
- Sabrina Giantulli
- grid.7841.aDepartment of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Elisabetta Tortorella
- grid.7841.aDepartment of Molecular Medicine, Sapienza University of Rome, Rome, Italy ,grid.6530.00000 0001 2300 0941Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Rome, Italy
| | - Francesco Brasili
- grid.6530.00000 0001 2300 0941Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Rome, Italy ,grid.7841.aDepartment of Physics, Sapienza University of Rome, Rome, Italy ,grid.5326.20000 0001 1940 4177CNR-NANOTEC, Institute of Nanotechnology, Soft and Living Matter Laboratory, Rome, Italy
| | - Susanna Scarpa
- grid.7841.aDepartment of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Barbara Cerroni
- grid.6530.00000 0001 2300 0941Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Rome, Italy
| | - Gaio Paradossi
- grid.6530.00000 0001 2300 0941Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Rome, Italy
| | - Angelico Bedini
- grid.425425.00000 0001 2218 2472INAIL, Italian Worker’s Compensation Authority, Rome, Italy
| | - Stefania Morrone
- grid.7841.aDepartment of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Ida Silvestri
- grid.7841.aDepartment of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Fabio Domenici
- grid.6530.00000 0001 2300 0941Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Rome, Italy
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Li Y, Liu G, Xiao F, Gu W, Gao Z, Wu Y, Wang P, Shi M, Yang M, Zhong Z, Liu B. Dual Role of Caveolin-1 in β-Catenin Signaling During Fracture Healing Induced by Low-Intensity Pulsed Ultrasound in Rabbits. J BIOMATER TISS ENG 2021. [DOI: 10.1166/jbt.2021.2553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We did this research to observe the effect of LIPUS on long bone fracture repair and caveolin-1, β-catenin signaling expression in the radius defects of rabbits, to explore its possible molecular mechanisms. 24 male New Zealand rabbits with bilateral radial bone defects
were divided into 4 groups randomly, n = 6. The right side had daily LIPUS exposure for 20 minutes, while the left received sham treatment. After 7, 14, 21, 28 days, respectively, fracture healing was observed by X-ray imaging and Dual Energy X-ray Absorptiometry (DXA) scan, specimens
were harvested for histology, immunohistochemistry, and gene expression analysis. We found that LIPUS brought forward endochondral ossification, increased the bone callus size without changes in Bone Mineral Density (BMD). The caveolin-1 expression increased first then decreased, while the
β-catenin kept growing during the process. These demonstrated that caveolin-1 participated in fracture healing accelerated by LIPUS, which was speculated to play a dual role in β-catenin signaling expression.
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Affiliation(s)
- Yun Li
- Department of Rehabilitation Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Guanghua Liu
- Department of Rehabilitation Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Feng Xiao
- Department of Pathology, Shanghai Seventh People’s Hospital, Shanghai 200137, China
| | - Wenqin Gu
- Department of Rehabilitation Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Zhengdong Gao
- Department of Radiology, Fenglin Community Health Service Center, Xuhui District, Shanghai 200030, China
| | - Yiming Wu
- Department of Rehabilitation Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Ping Wang
- Department of Rehabilitation Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Mingfang Shi
- Department of Rehabilitation Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Mingzhen Yang
- Department of Rehabilitation Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Zongye Zhong
- Department of Rehabilitation Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Bangzhong Liu
- Department of Rehabilitation Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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Valentin D, Presas A, Roehr C, Mele E, Biehl C, Heiss C, Bosbach WA. On the quantification of local power densities in a new vibration bioreactor. PLoS One 2021; 16:e0245768. [PMID: 33481928 PMCID: PMC7822512 DOI: 10.1371/journal.pone.0245768] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 01/07/2021] [Indexed: 12/30/2022] Open
Abstract
We investigate the power densities which are obtainable locally in a vibration bioreactor. These reactor systems are of great relevance for research about oncological or antibacterial therapies. Our focus lies on the local liquid pressure caused by resonance vibration in the fluid contained by the reactor's petri dish. We use for the excitation one piezoelectric patch which offer advantages concerning controllability and reproducibility, when compared to ultrasound. The experimental work is extended by finite element analyses of bioreactor details. The peaks of the vibration response for water, sodium chloride (0.1N Standard solution), and McCoy's 5A culture medium are in good alignment. Several natural frequencies can be observed. Local power density can reach multiple times the magnitude used in ultrasound studies. Based on the observed local power densities, we are planning future work for the exposure of cell cultures to mechanical vibration.
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Affiliation(s)
- David Valentin
- Center for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Barcelona, Spain
| | - Alexandre Presas
- Center for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), Barcelona, Spain
| | - Charline Roehr
- Experimental Trauma Surgery, Justus-Liebig University of Giessen, Giessen, Germany
| | - Elisa Mele
- Materials Department, Loughborough University, Loughborough, United Kingdom
| | - Christoph Biehl
- Experimental Trauma Surgery, Justus-Liebig University of Giessen, Giessen, Germany
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital of Giessen, Giessen, Germany
| | - Christian Heiss
- Experimental Trauma Surgery, Justus-Liebig University of Giessen, Giessen, Germany
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital of Giessen, Giessen, Germany
| | - Wolfram A. Bosbach
- Experimental Trauma Surgery, Justus-Liebig University of Giessen, Giessen, Germany
- Department of Trauma, Hand and Reconstructive Surgery, University Hospital of Giessen, Giessen, Germany
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Valentin D, Roehr C, Presas A, Heiss C, Egusquiza E, Bosbach WA. Experimental and Numerical Design and Evaluation of a Vibration Bioreactor using Piezoelectric Patches. SENSORS (BASEL, SWITZERLAND) 2019; 19:E436. [PMID: 30669693 PMCID: PMC6359548 DOI: 10.3390/s19020436] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/16/2019] [Accepted: 01/16/2019] [Indexed: 11/16/2022]
Abstract
In this present study, we propose a method for exposing biological cells to mechanical vibration. The motive for our research was to design a bioreactor prototype in which in-depth in vitro studies about the influence of vibration on cells and their metabolism can be performed. The therapy of cancer or antibacterial measures are applications of interest. In addition, questions about the reaction of neurons to vibration are still largely unanswered. In our methodology, we used a piezoelectric patch (PZTp) for inducing mechanical vibration to the structure. To control the vibration amplitude, the structure could be excited at different frequency ranges, including resonance and non-resonance conditions. Experimental results show the vibration amplitudes expected for every frequency range tested, as well as the vibration pattern of those excitations. These are essential parameters to quantify the effect of vibration on cell behavior. Furthermore, a numerical model was validated with the experimental results presenting accurate results for the prediction of those parameters. With the calibrated numerical model, we will study in greater depth the effects of different vibration patterns for the abovementioned cell types.
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Affiliation(s)
- David Valentin
- Center for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), 08034 Barcelona, Spain.
| | - Charline Roehr
- Experimental Trauma Surgery, Justus Liebig University of Giessen, Germany.
| | - Alexandre Presas
- Center for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), 08034 Barcelona, Spain.
- Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China.
| | - Christian Heiss
- Experimental Trauma Surgery, Justus Liebig University of Giessen, Germany.
| | - Eduard Egusquiza
- Center for Industrial Diagnostics and Fluid Dynamics (CDIF), Polytechnic University of Catalonia (UPC), 08034 Barcelona, Spain.
| | - Wolfram A Bosbach
- Experimental Trauma Surgery, Justus Liebig University of Giessen, Germany.
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Eguchi K, Shindo T, Ito K, Ogata T, Kurosawa R, Kagaya Y, Monma Y, Ichijo S, Kasukabe S, Miyata S, Yoshikawa T, Yanai K, Taki H, Kanai H, Osumi N, Shimokawa H. Whole-brain low-intensity pulsed ultrasound therapy markedly improves cognitive dysfunctions in mouse models of dementia - Crucial roles of endothelial nitric oxide synthase. Brain Stimul 2018; 11:959-973. [PMID: 29857968 DOI: 10.1016/j.brs.2018.05.012] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 05/01/2018] [Accepted: 05/20/2018] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Therapeutic focused-ultrasound to the hippocampus has been reported to exert neuroprotective effects on dementia. In the present study, we examined whether the whole-brain LIPUS (low-intensity pulsed ultrasound) therapy is effective and safe in 2 mouse models of dementia (vascular dementia, VaD and Alzheimer's disease, AD), and if so, to elucidate the common underlying mechanism(s) involved. METHODS We used bilateral carotid artery stenosis (BCAS) model with micro-coils in male C57BL/6 mice as a VaD model and 5XFAD transgenic mice as an AD model. We applied the LIPUS therapy (1.875 MHz, 6.0 kHz, 32cycles) to the whole brain. RESULTS In both models, the LIPUS therapy markedly ameliorated cognitive impairments (Y-maze test and/or passive avoidance test) associated with improved cerebral blood flow (CBF). Mechanistically, the LIPUS therapy significantly increased CD31-positive endothelial cells and Olig2-positive oligodendrocyte precursor cells (OPCs) in the VaD model, while it reduced Iba-1-positive microglias and amyloid-β (Aβ) plaque in the AD model. In both models, endothelium-related genes were significantly upregulated in RNA-sequencing, and expressions of endothelial nitric oxide synthase (eNOS) and neurotrophins were upregulated in Western blotting. Interestingly, the increases in glia cells and neurotrophin expressions showed significant correlations with eNOS expression. Importantly, these beneficial effects of LIPUS were absent in eNOS-knockout mice. CONCLUSIONS These results indicate that the whole-brain LIPUS is an effective and non-invasive therapy for dementia by activating specific cells corresponding to each pathology, for which eNOS activation plays an important role as a common mechanism.
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Affiliation(s)
- Kumiko Eguchi
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Tomohiko Shindo
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kenta Ito
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Tsuyoshi Ogata
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ryo Kurosawa
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yuta Kagaya
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yuto Monma
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Sadamitsu Ichijo
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Sachie Kasukabe
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Satoshi Miyata
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Takeo Yoshikawa
- Department of Pharmacology, Tohoku University School of Medicine Sendai, Japan
| | - Kazuhiko Yanai
- Department of Pharmacology, Tohoku University School of Medicine Sendai, Japan
| | - Hirofumi Taki
- Biomedical Engineering for Health and Welfare, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Hiroshi Kanai
- Department of Electronic Engineering, Tohoku University Graduate School of Engineering, Sendai, Japan
| | - Noriko Osumi
- Department of Developmental Neuroscience, Tohoku University, Sendai, Japan
| | - Hiroaki Shimokawa
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Hu Y, Wan JMF, Yu ACH. Cytomechanical perturbations during low-intensity ultrasound pulsing. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:1587-98. [PMID: 24642219 DOI: 10.1016/j.ultrasmedbio.2014.01.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 12/23/2013] [Accepted: 01/07/2014] [Indexed: 05/24/2023]
Abstract
To establish the therapeutic potential of low-intensity ultrasound, it is important to characterize its biophysical interactions with living cells. Here, through a series of single-cell direct observations, we show that low-intensity ultrasound pulsing would give rise to a dynamic course of cytomechanical perturbations at both the membrane and nucleus levels. Our investigation was conducted using a composite platform that coupled a 1-MHz ultrasound exposure hardware to a confocal microscopy system. Short ultrasound pulses (5 cycles, 2-kHz pulse repetition frequency) with a spatial-peak time-averaged intensity of 0.24 W/cm(2) (0.85-MPa peak positive acoustic pressure) were delivered over a 10-min period to adherent Neuro-2a neuroblastoma cells, and live imaging of cellular dynamics was performed before, during and after the exposure period. Bright-field imaging results revealed progressive shrinkage of cellular cross-sectional area (25%-45%, N = 7) during low-intensity ultrasound pulsing; the initial rate of size decrease was estimated to be 8%-14% per minute. This shrinkage was found to be transient, as the sonicated cells had recovered (at a rate of size increase of 0.4%-0.9% per minute) to their pre-exposure size within 30 min after the end of exposure. Three-dimensional confocal imaging results further revealed that (i) ultrasound-induced membrane contraction was volumetric in nature (21%-45% reduction), and (ii) a concomitant decrease in nucleus volume was evident (12%-25% reduction). Together, these findings indicate that low-intensity ultrasound pulsing, if applied on the order of minutes, would reversibly perturb the physical and subcellular structures of living cells.
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Affiliation(s)
- Yaxin Hu
- Medical Engineering Program, University of Hong Kong, Pokfulam, Hong Kong
| | - Jennifer M F Wan
- Medical Engineering Program, University of Hong Kong, Pokfulam, Hong Kong
| | - Alfred C H Yu
- Medical Engineering Program, University of Hong Kong, Pokfulam, Hong Kong.
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11
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Matsumoto T, Kuriwaka-Kido R, Kondo T, Endo I, Kido S. Regulation of osteoblast differentiation by interleukin-11 via AP-1 and Smad signaling. Endocr J 2012; 59:91-101. [PMID: 21931225 DOI: 10.1507/endocrj.ej11-0219] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Mechanical stress and parathyroid hormone (PTH) are major stimulators, and aging and glucocorticoids excess are important suppressors of osteoblast differentiation. Mechanical stress and PTH stimulate interleukin (IL)-11 expression in cells of osteoblast lineage by enhancing transcription of IL-11 gene via an increase in intracellular Ca²⁺. The elevated Ca²⁺ activates extracellular signal-regulated kinase (ERK) to enhance phosphorylation of cyclic AMP response element-binding protein (CREB), which binds to the fosB gene promoter and enhances ΔFosB expression. ΔFosB dimerizes with JunD on the IL-11 gene promoter to enhance its transcription. Both mechanical stress and PTH also stimulate phosphorylation of Smad1 via an activation of protein kinase Cδ (PKCδ). Phosphorylated Smad1 binds to the IL-11 gene promoter and forms complex with ΔFosB/JunD to further enhance IL-11 gene transcription. The increased IL-11 then suppresses expression of Wnt inhibitors, including Dickkopf 1 (Dkk1) and 2, and enhances Wnt signaling to stimulate osteoblast differentiation and inhibit adipocyte differentiation. The suppression of osteoblast differentiation by aging involves a decrease in IL-11 gene transcription by a reduction in JunD binding to the activator protein (AP)-1 site of the IL-11 gene promoter. Glucocorticoids inhibit transcriptional activation of IL-11 gene by an interaction of glucocorticoid-glucocorticoid receptor (GR) complex with ΔFosB/JunD heterodimer. Thus, factors that enhance osteoblast differentiation stimulate, and those which suppress osteoblast differentiation inhibit IL-11 gene transcription, and IL-11 enhances Wnt signaling by suppressing expression of its inhibitors. These observations are consistent with the notion that IL-11 mediates stimulatory and inhibitory signals of osteoblast differentiation by affecting Wnt signaling.
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Affiliation(s)
- Toshio Matsumoto
- Department of Medicine and Bioregulatory Sciences, The University of Tokushima Graduate School of Medical Sciences, Tokushima, Japan.
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12
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Angle SR, Sena K, Sumner DR, Virdi AS. Osteogenic differentiation of rat bone marrow stromal cells by various intensities of low-intensity pulsed ultrasound. ULTRASONICS 2011; 51:281-288. [PMID: 20965537 DOI: 10.1016/j.ultras.2010.09.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 08/24/2010] [Accepted: 09/21/2010] [Indexed: 05/30/2023]
Abstract
Bone growth and repair are under the control of biochemical and mechanical signals. Low-intensity pulsed ultrasound (LIPUS) stimulation at 30mW/cm(2) is an established, widely used and FDA approved intervention for accelerating bone healing in fractures and non-unions. Although this LIPUS signal accelerates mineralization and bone regeneration, the actual intensity experienced by the cells at the target site might be lower, due to the possible attenuation caused by the overlying soft tissue. The aim of this study was to investigate whether LIPUS intensities below 30mW/cm(2) are able to provoke phenotypic responses in bone cells. Rat bone marrow stromal cells were cultured under defined conditions and the effect of 2, 15, 30mW/cm(2) and sham treatments were studied at early (cell activation), middle (differentiation into osteogenic cells) and late (biological mineralization) stages of osteogenic differentiation. We observed that not only 30mW/cm(2) but also 2 and 15mW/cm(2), modulated ERK1/2 and p38 intracellular signaling pathways as compared to the sham treatment. After 5 days with daily treatments of 2, 15 and 30mW/cm(2), alkaline phosphatase activity, an early indicator of osteoblast differentiation, increased by 79%, 147% and 209%, respectively, compared to sham, indicating that various intensities of LIPUS were able to initiate osteogenic differentiation. While all LIPUS treatments showed higher mineralization, interestingly, the highest increase of 225% was observed in cells treated with 2mW/cm(2). As the intensity increased to 15 and 30mW/cm(2), the increase in the level of mineralization dropped to 120% and 82%. Our data show that LIPUS intensities lower than the current clinical standard have a positive effect on osteogenic differentiation of rat bone marrow stromal cells. Although Exogen™ at 30mW/cm(2) continues to be effective and should be used as a clinical therapy for fracture healing, if confirmed in vivo, the increased mineralization at lower intensities might be the first step towards redefining the most effective LIPUS intensity for clinical use.
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Affiliation(s)
- S R Angle
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, IL 60612, USA
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13
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Saini V, McCormick S. Changes in NO, iNOS and eNOS Expression in MLO-Y4 Cells After Low-intensity Pulsed Ultrasound Treatment With or Without Shear Stress Exposure. Cell Mol Bioeng 2010. [DOI: 10.1007/s12195-010-0154-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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14
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Low-intensity pulsed ultrasound modulates shear stress induced PGHS-2 expression and PGE2 synthesis in MLO-Y4 osteocyte-like cells. Ann Biomed Eng 2010; 39:378-93. [PMID: 20820919 DOI: 10.1007/s10439-010-0156-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2010] [Accepted: 08/25/2010] [Indexed: 02/01/2023]
Abstract
Fluid shear stress (SS) has been shown to be a prevailing physiological stimulus in the regulation of bone cell metabolism and so are the exogenous biomechanical forces, like ultrasound (US) and vibration. The purpose of this study is to elaborate the interplay of laminar fluid SS with low-intensity pulsed US in the regulation of prostaglandin H synthase 2 (PGHS-2) and prostaglandin E2 (PGE2). Murine long bone osteocyte-like (MLO-Y4) cells were exposed to various regimes of US (1.5 Hz, 30 mW/cm2) and SS (19 dyn/cm2) alone and sequentially. Changes in PGHS-2 gene expression levels were quantified at 3 and 24 h using real-time RT-PCR. PGE2 levels in the culture media were measured using enzyme immunoassay at 3 and 24 h. PGE2 levels significantly increased after exposure to SS for 3 and 24 h by 2.17±0.02 and 5.47±0.42-fold, respectively, compared to control cells. A 20 min US treatment prior to SS significantly increased SS PGE2 levels 2.95±0.18 and 2.90±0.50-fold at 3 and 24 h, respectively. US also significantly increased PGHS-2 mRNA levels in cells exposed to SS. SS caused a 2.74 ± 0.49-fold increase in PGHS-2 mRNA levels at 3 h and a significant 3.70±0.25-fold increase at 24 h relative to control. A 20 min US treatment caused 1.35±0.49 and 2.44±0.82-fold increase in PGHS-2 mRNA levels in cells exposed to SS at 3 and 24 h, respectively. These results indicate that combining US with SS may have a more anabolic benefit for bone tissue than either stimulus alone.
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15
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Sharp LA, Lee YW, Goldstein AS. Effect of low-frequency pulsatile flow on expression of osteoblastic genes by bone marrow stromal cells. Ann Biomed Eng 2009; 37:445-53. [PMID: 19130228 DOI: 10.1007/s10439-008-9632-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2008] [Accepted: 12/23/2008] [Indexed: 11/24/2022]
Abstract
Perfusion culture of osteoprogenitor cells is a promising means to form a bone-like extracellular matrix for tissue engineering applications, but the mechanism by which hydrodynamic shear stimulates expression of bone extracellular matrix (ECM) proteins is not understood. Osteoblasts are mechanosensitive and respond differently to steady and pulsatile flow. Therefore, to probe the effect of flow, bone marrow stromal cells (BMSCs)--cultured under osteogenic conditions--were exposed to steady or pulsatile flow at frequencies of 0.015, 0.044, or 0.074 Hz. Following 24 h of stimulus, cells were cultured statically for an additional 13 days and then analyzed for the expression of bone ECM proteins collagen 1alpha1 (Col1alpha1), osteopontin, osteocalcin (OC), and bone sialoprotein (BSP). All mRNA levels were elevated by flow, but OC and BSP were enhanced modestly with pulsatile flow. To determine if these effects were related to gene induction during flow, BMSCs were again exposed to steady or pulsatile flow for 24 h, but then analyzed immediately for expression of growth and differentiation factors bone morphogenetic proteins (BMP)-2, -4, and -7, transforming growth factor (TGF)-beta1, and vascular endothelial growth factor-A. All growth and differentiation factors were significantly elevated by flow, except BMP-4 which was suppressed. In addition, expression of BMP-2 and -7 were enhanced and TGF-beta1 suppressed by pulsatile flow relative to steady flow. These results demonstrate that pulsatile flow modulates expression of BMP-2, -7, and TGF-beta1 and suggest that enhanced expression of bone ECM proteins by pulsatile flow may be mediated through the induction of BMP-2 and -7.
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Affiliation(s)
- Lindsay A Sharp
- Department of Chemical Engineering, 0211, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0211, USA
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16
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Lu H, Qin L, Lee K, Cheung W, Chan K, Leung K. Identification of genes responsive to low-intensity pulsed ultrasound stimulations. Biochem Biophys Res Commun 2008; 378:569-73. [PMID: 19056340 DOI: 10.1016/j.bbrc.2008.11.074] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2008] [Accepted: 11/18/2008] [Indexed: 11/24/2022]
Abstract
This study was designed to compare the temporal changes of gene expression profile in osteoblastic cell lines (SaOS-2) treated with low-intensity pulsed ultrasound stimulation (LIPUS) using complementary DNA (cDNA) microarrays. SaOS-2 cells were treated with LIPUS for 20min. Thereafter, cells were harvested and RNA was extracted twice at 4 and 24h, respectively. Using cDNA microarrays, 7488 genes with changes in expression in SaOS-2 cells were identified for comparison. Microarray analysis revealed a total of 165 genes in SaOS-2 cells were regulated at 4 and 24h after LIPUS treatment. Except for 30 known LIPUS-regulated genes, our study demonstrated for the first time that over 100 genes were related to the underlying molecular mechanism of LIPUS and suggested that LIPUS might regulate a transient expression of numerous critical genes in osteoblastic cells. These results provide further understanding of the role of LIPUS in the regulation of osteoblastic gene expression potentially involved in the molecular mechanism of osteogenesis in fracture repair.
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Affiliation(s)
- Hongbin Lu
- Musculoskeletal Research Laboratory, Department of Orthopaedics & Traumatology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, PR China
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17
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Chondrogenesis, bone morphogenetic protein-4 and mesenchymal stem cells. Osteoarthritis Cartilage 2008; 16:1121-30. [PMID: 18406633 DOI: 10.1016/j.joca.2008.03.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Accepted: 03/02/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE As adult cartilage has very limited potential to regenerate, cartilage repair is challenging. Available treatments have several disadvantages, including formation of fibrocartilage instead of hyaline-like cartilage, as well as eventual ossification of the newly formed tissue. The focus of this review is the application of bone morphogenetic protein-4 (BMP-4) and mesenchymal stem cells (MSCs) in cartilage repair, a combination that could potentially lead to the formation of permanent hyaline-like cartilage in the defect. METHODS This review is based on recent literature in the orthopaedic and tissue engineering fields, and is focused on MCSs and bone morphogenetic proteins (BMPs). RESULTS BMP-4, a stimulator of chondrogenesis, both in vitro and in vivo, is a potential therapeutic agent for cartilage regeneration. BMP-4 delivery can improve the healing process of an articular cartilage defect by stimulating the synthesis of the cartilage matrix constituents: type II collagen and aggrecan. BMP-4 has also been shown to suppress chondrogenic hypertrophy and maintain regenerated cartilage. Use of an appropriate carrier for BMP-4 is crucial for successful reconstruction of cartilage defects. Due to the relatively short half-life in vivo of BMP-4, there is a need to localize and maintain the delivery of BMP-4 to the injury site. Additionally, the delivery of MSCs to the wound site could improve cartilage regeneration; therefore, the carrier should function both as a cell and a protein delivery vehicle. CONCLUSION The role of BMP-4 in chondrogenesis is significant, and successful methods to deliver BMP-4, with or without MSCs, to the cartilage defect site are a promising therapy to treat cartilage defects.
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Pounder NM, Harrison AJ. Low intensity pulsed ultrasound for fracture healing: a review of the clinical evidence and the associated biological mechanism of action. ULTRASONICS 2008; 48:330-338. [PMID: 18486959 DOI: 10.1016/j.ultras.2008.02.005] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Revised: 11/15/2007] [Accepted: 02/28/2008] [Indexed: 05/26/2023]
Abstract
Low intensity pulsed ultrasound is used in the clinical treatment of fractures and other osseous defects. Level I clinical studies demonstrate the ability of a specific ultrasound signal (1.5 MHz ultrasound pulsed at 1 kHz, 20% duty cycle, 30 mW/cm(2) intensity (SATA)) to accelerate the healing time in fresh tibia, radius and scaphoid fractures by up to 40%. Additionally, the same ultrasound signal has been shown to be effective at resolving all types of nonunions of all ages, following a wide range of fracture types and primary fracture management techniques. Recently, significant efforts have resulted in a more comprehensive understanding of the biological mechanism of action that produces the documented clinical outcomes. Low intensity pulsed ultrasound has been demonstrated to accelerate in vivo all stages of the fracture repair process (inflammation, soft callus formation, hard callus formation). In particular, accelerated mineralisation has been demonstrated in vitro with increases in osteocalcin, alkaline phosphatase, VEGF and MMP-13 expression. Integrins, a family of mechanoreceptors present on a wide range of cells involved in the fracture healing process, have been shown to be activated by the ultrasound signal. Downstream of the integrin activation, focal adhesions occur on the surface of cells with the activation of multiple signalling pathways, including the ERK, NF-kappabeta, and PI3 kinase pathways. These pathways have been directly linked to the production of COX-2 and prostaglandin, which are key to the processes of mineralisation and endochondral ossification in fracture healing.
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Affiliation(s)
- Neill M Pounder
- Orthopaedic Trauma and Clinical Therapies, Smith and Nephew, Inc., Memphis, TN 38116, USA.
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