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Khan B, Nippolainen E, Shahini F, Torniainen J, Mikkonen S, Nonappa, Popov A, Töyräs J, Afara IO. Refractive index of human articular cartilage varies with tissue structure and composition. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2023; 40:2205-2214. [PMID: 38086029 DOI: 10.1364/josaa.498722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/19/2023] [Indexed: 12/18/2023]
Abstract
Optical properties of biological tissues, such as refractive index, are fundamental properties, intrinsically linked to a tissue's composition and structure. This study aims to investigate the variation of refractive index (RI) of human articular cartilage along the tissue depth (via collagen fibril orientation and optical density) and integrity (based on Mankin and Osteoarthritis Research Society International (OARSI) scores). The results show the relationship between RI and PG content (p=0.042), collagen orientation (p=0.037), and OARSI score (p=0.072). When taken into account, the outcome of this study suggests that the RI of healthy cartilage differs from that of pathological cartilage (p=0.072). This could potentially provide knowledge on how progressive tissue degeneration, such as osteoarthritis, affects changes in cartilage RI, which can, in turn, be used as a potential optical biomarker of tissue pathology.
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Hosokawa Y, Onodera T, Homan K, Yamaguchi J, Kudo K, Kameda H, Sugimori H, Iwasaki N. Establishment of a New Qualitative Evaluation Method for Articular Cartilage by Dynamic T2w MRI Using a Novel Contrast Medium as a Water Tracer. Cartilage 2022; 13:19476035221111503. [PMID: 36072990 PMCID: PMC9459471 DOI: 10.1177/19476035221111503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE In the early stages of cartilage damage, diagnostic methods focusing on the mechanism of maintaining the hydrostatic pressure of cartilage are thought to be useful. 17O-labeled water, which is a stable isotope of oxygen, has the advantage of no radiation exposure or allergic reactions and can be detected by magnetic resonance imaging (MRI). This study aimed to evaluate MRI images using 17O-labeled water in a rabbit model. DESIGN Contrast MRI with 17O-labeled water and macroscopic and histological evaluations were performed 4 and 8 weeks after anterior cruciate ligament transection surgery in rabbits. A total of 18 T2-weighted images were acquired, and 17O-labeled water was manually administered on the third scan. The 17O concentration in each phase was calculated from the signal intensity at the articular cartilage. Macroscopic and histological grades were evaluated and compared with the 17O concentration. RESULTS An increase in 17O concentration in the macroscopic and histologically injured areas was observed by MRI. Macroscopic evaluation showed that the 17O concentration significantly increased in the damaged site group. Histological evaluations also showed that 17O concentrations significantly increased at 36 minutes 30 seconds after initiating MRI scanning in the Osteoarthritis Research Society International (OARSI) grade 3 (0.493 in grade 0, 0.659 in grade 1, 0.4651 in grade 2, and 0.9964 in grade 3, P < 0.05). CONCLUSION 17O-labeled water could visualize earlier articular cartilage damage, which is difficult to detect by conventional methods.
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Affiliation(s)
- Yoshiaki Hosokawa
- Department of Orthopaedic Surgery,
Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo,
Japan
| | - Tomohiro Onodera
- Department of Orthopaedic Surgery,
Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo,
Japan,Tomohiro Onodera, Department of Orthopaedic
Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido
University, Sapporo 060-8648, Japan.
| | - Kentaro Homan
- Department of Orthopaedic Surgery,
Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo,
Japan
| | - Jun Yamaguchi
- Department of Orthopaedic Surgery,
Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo,
Japan
| | - Kohsuke Kudo
- Department of Diagnostic Imaging,
Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroyuki Kameda
- Department of Diagnostic Imaging,
Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | | | - Norimasa Iwasaki
- Department of Orthopaedic Surgery,
Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo,
Japan
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Hafner T, Schock J, Post M, Abrar DB, Sewerin P, Linka K, Knobe M, Kuhl C, Truhn D, Nebelung S. A serial multiparametric quantitative magnetic resonance imaging study to assess proteoglycan depletion of human articular cartilage and its effects on functionality. Sci Rep 2020; 10:15106. [PMID: 32934341 PMCID: PMC7492285 DOI: 10.1038/s41598-020-72208-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023] Open
Abstract
Water, collagen, and proteoglycans determine articular cartilage functionality. If altered, susceptibility to premature degeneration is increased. This study investigated the effects of enzymatic proteoglycan depletion on cartilage functionality as assessed by advanced Magnetic Resonance Imaging (MRI) techniques under standardized loading. Lateral femoral condylar cartilage-bone samples from patients undergoing knee replacement (n = 29) were serially imaged by Proton Density-weighted and T1, T1ρ, T2, and T2* mapping sequences on a clinical 3.0 T MRI scanner (Achieva, Philips). Using pressure-controlled indentation loading, samples were imaged unloaded and quasi-statically loaded to 15.1 N and 28.6 N, and both before and after exposure to low-concentrated (LT, 0.1 mg/mL, n = 10) or high-concentrated trypsin (HT, 1.0 mg/mL, n = 10). Controls were not treated (n = 9). Responses to loading were assessed for the entire sample and regionally, i.e. sub- and peri-pistonally, and zonally, i.e. upper and lower sample halves. Trypsin effects were quantified as relative changes (Δ), analysed using appropriate statistical tests, and referenced histologically. Histological proteoglycan depletion was reflected by significant sub-pistonal decreases in T1 (p = 0.003) and T2 (p = 0.008) after HT exposure. Loading-induced changes in T1ρ and T2* were not related. In conclusion, proteoglycan depletion alters cartilage functionality and may be assessed using serial T1 and T2 mapping under loading.
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Affiliation(s)
- Tobias Hafner
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany
| | - Justus Schock
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Hospital Düsseldorf, Moorenstraße 5, 40225, Dusseldorf, Germany.,Institute of Computer Vision and Imaging, RWTH University Aachen, Aachen, Germany
| | - Manuel Post
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany
| | - Daniel Benjamin Abrar
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Hospital Düsseldorf, Moorenstraße 5, 40225, Dusseldorf, Germany
| | - Philipp Sewerin
- Medical Faculty, Department and Hiller-Research-Unit for Rheumatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Kevin Linka
- Department of Continuum and Materials Mechanics, Hamburg University of Technology, Hamburg, Germany
| | - Matthias Knobe
- Clinic for Orthopaedic and Trauma Surgery, Cantonal Hospital Luzern, Luzern, Switzerland
| | - Christiane Kuhl
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany
| | - Daniel Truhn
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany
| | - Sven Nebelung
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Hospital Düsseldorf, Moorenstraße 5, 40225, Dusseldorf, Germany.
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Zhang J, Xiao L, Tong L, Wan C, Hao Z. Quantitative Evaluation of Enzyme-Induced Porcine Articular Cartilage Degeneration Based on Observation of Entire Cartilage Layer Using Ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:861-871. [PMID: 29352619 DOI: 10.1016/j.ultrasmedbio.2017.11.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 11/18/2017] [Accepted: 11/27/2017] [Indexed: 06/07/2023]
Abstract
Enzyme-induced articular cartilage degeneration resembling osteoarthritis was evaluated using a newly defined acoustic parameter, the "averaged magnitude ratio" (AMR), which has been suggested as an indicator of articular cartilage degeneration. In vitro experiments were conducted on porcine cartilage samples digested with trypsin for 2 h (n = 10) and 4 h (n = 13) and healthy control samples (n = 13). AMR was determined with 15- and 25-MHz ultrasound, and the integrated reflection coefficient (IRC) and apparent integrated backscattering coefficient (AIB) were also calculated for comparison. The Young's modulus of superficial cartilage was measured using atomic force microscopy. Performance of the AMR differs between 15 and 25 MHz, possibly because of frequency-related attenuation and resolution of ultrasound. At the proper settings, AMR exhibited a competence similar to that of IRC and AIB in detecting cartilage degeneration and could also detect differences in deeper positions. Furthermore, AMR has the advantages of being easy to measure and requiring no reference material.
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Affiliation(s)
- Jingchen Zhang
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Liying Xiao
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Lingying Tong
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Chao Wan
- Department of Mechanical Engineering, Tsinghua University, Beijing, China; Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing, China
| | - Zhixiu Hao
- Department of Mechanical Engineering, Tsinghua University, Beijing, China.
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Wang K, Wu J, Day R, Kirk TB, Hu X. Characterizing depth-dependent refractive index of articular cartilage subjected to mechanical wear or enzymic degeneration. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:95002. [PMID: 27626900 DOI: 10.1117/1.jbo.21.9.095002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 08/29/2016] [Indexed: 06/06/2023]
Abstract
Utilizing a laser scanning confocal microscope system, the refractive indices of articular cartilage (AC) with mechanical or biochemical degenerations were characterized to investigate whether potential correlations exist between refractive index (RI) and cartilage degeneration. The cartilage samples collected from the medial femoral condyles of kangaroo knees were mechanically degenerated under different loading patterns or digested in trypsin solution with different concentrations. The sequences of RI were then measured from cartilage surface to deep region and the fluctuations of RI were quantified considering combined effects of fluctuating frequency and amplitude. The compositional and microstructural alterations of cartilage samples were assessed with histological methods. Along with the loss of proteoglycans, the average RI of cartilage increased and the local fluctuation of RI became stronger. Short-term high-speed test induced little influence to both the depth fluctuation and overall level of RI. Long-term low-speed test increased the fluctuation of RI but the average RI was barely changed. The results substantially demonstrate that RI of AC varies with both compositional and structural alterations and is potentially an indicator for the degeneration of AC.
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Affiliation(s)
- Kuyu Wang
- University of Western Australia, School of Mechanical and Chemical Engineering, 35 Stirling Highway, Crawley, Perth, Western Australia 6009, Australia
| | - Jianping Wu
- Curtin University, Department of Mechanical Engineering, Perth, Western Australia 6102, Australia
| | - Robert Day
- University of Western Australia, School of Mechanical and Chemical Engineering, 35 Stirling Highway, Crawley, Perth, Western Australia 6009, AustraliacRoyal Perth Hospital, Department of Medical Engineering and Physics, Perth, Western Australia 6000, Australia
| | - Thomas Brett Kirk
- Curtin University, Department of Mechanical Engineering, Perth, Western Australia 6102, Australia
| | - Xiaozhi Hu
- University of Western Australia, School of Mechanical and Chemical Engineering, 35 Stirling Highway, Crawley, Perth, Western Australia 6009, Australia
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Manzano S, Manzano R, Doblaré M, Doweidar MH. Altered swelling and ion fluxes in articular cartilage as a biomarker in osteoarthritis and joint immobilization: a computational analysis. J R Soc Interface 2015; 12:20141090. [PMID: 25392400 DOI: 10.1098/rsif.2014.1090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In healthy cartilage, mechano-electrochemical phenomena act together to maintain tissue homeostasis. Osteoarthritis (OA) and degenerative diseases disrupt this biological equilibrium by causing structural deterioration and subsequent dysfunction of the tissue. Swelling and ion flux alteration as well as abnormal ion distribution are proposed as primary indicators of tissue degradation. In this paper, we present an extension of a previous three-dimensional computational model of the cartilage behaviour developed by the authors to simulate the contribution of the main tissue components in its behaviour. The model considers the mechano-electrochemical events as concurrent phenomena in a three-dimensional environment. This model has been extended here to include the effect of repulsion of negative charges attached to proteoglycans. Moreover, we have studied the fluctuation of these charges owning to proteoglycan variations in healthy and pathological articular cartilage. In this sense, standard patterns of healthy and degraded tissue behaviour can be obtained which could be a helpful diagnostic tool. By introducing measured properties of unhealthy cartilage into the computational model, the severity of tissue degeneration can be predicted avoiding complex tissue extraction and subsequent in vitro analysis. In this work, the model has been applied to monitor and analyse cartilage behaviour at different stages of OA and in both short (four, six and eight weeks) and long-term (11 weeks) fully immobilized joints. Simulation results showed marked differences in the corresponding swelling phenomena, in outgoing cation fluxes and in cation distributions. Furthermore, long-term immobilized patients display similar swelling as well as fluxes and distribution of cations to patients in the early stages of OA, thus, preventive treatments are highly recommended to avoid tissue deterioration.
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Affiliation(s)
- Sara Manzano
- Group of Structural Mechanics and Materials Modelling (GEMM), Aragón Institute of Engineering Research (I3A), University of Zaragoza, Spain Mechanical Engineering Department, School of Engineering and Architecture (EINA), University of Zaragoza, Spain Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Spain
| | - Raquel Manzano
- LAGENBIO-I3A, Veterinary School, University of Zaragoza, Spain
| | - Manuel Doblaré
- Group of Structural Mechanics and Materials Modelling (GEMM), Aragón Institute of Engineering Research (I3A), University of Zaragoza, Spain Mechanical Engineering Department, School of Engineering and Architecture (EINA), University of Zaragoza, Spain Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Spain
| | - Mohamed Hamdy Doweidar
- Group of Structural Mechanics and Materials Modelling (GEMM), Aragón Institute of Engineering Research (I3A), University of Zaragoza, Spain Mechanical Engineering Department, School of Engineering and Architecture (EINA), University of Zaragoza, Spain Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Spain
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Boettcher K, Grumbein S, Winkler U, Nachtsheim J, Lieleg O. Adapting a commercial shear rheometer for applications in cartilage research. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:093903. [PMID: 25273735 DOI: 10.1063/1.4894820] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cartilage research typically requires a broad range of experimental characterization techniques and thus various testing setups. Here, we describe how several of those tests can be performed with a single experimental platform, i.e. a commercial shear rheometer. Although primarily designed for shear experiments, such a rheometer can be equipped with different adapters to perform indentation and creep measurements, quantify alterations in the sample thickness, and conduct friction measurements in addition to shear rheology. Beyond combining four distinct experimental methods into one setup, the modified rheometer allows for performing material characterizations over a broad range of time scales, frequencies, and normal loads.
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Affiliation(s)
- K Boettcher
- Zentralinstitut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
| | - S Grumbein
- Zentralinstitut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
| | - U Winkler
- Zentralinstitut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
| | - J Nachtsheim
- Zentralinstitut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
| | - O Lieleg
- Zentralinstitut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
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8
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Wang Q, Yang YY, Niu HJ, Zhang WJ, Feng QJ, Chen WF. An ultrasound study of altered hydration behaviour of proteoglycan-degraded articular cartilage. BMC Musculoskelet Disord 2013; 14:289. [PMID: 24119051 PMCID: PMC3819513 DOI: 10.1186/1471-2474-14-289] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 09/19/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Articular cartilage is a solid-fluid biphasic material covering the bony ends of articulating joints. Hydration of articular cartilage is important to joint lubrication and weight-wearing. The aims of this study are to measure the altered hydration behaviour of the proteoglycan-degraded articular cartilage using high-frequency ultrasound and then to investigate the effect of proteoglycan (PG) degradation on cartilage hydration. METHODS Twelve porcine patellae with smooth cartilage surface were prepared and evenly divided into two groups: normal group without any enzyme treatment and trypsin group treated with 0.25% trypsin solution for 4 h to digest PG in the tissue. After 40-minute exposure to air at room temperature, the specimens were immerged into the physiological saline solution. The dehydration induced hydration behaviour of the specimen was monitored by the high-frequency (25 MHz) ultrasound pulser/receiver (P/R) system. Dynamic strain and equilibrium strain were extracted to quantitatively evaluate the hydration behaviour of the dehydrated cartilage tissues. RESULTS The hydration progress of the dehydrated cartilage tissue was observed in M-mode ultrasound image indicating that the hydration behaviour of the PG-degraded specimens decreased. The percentage value of the equilibrium strain (1.84 ± 0.21%) of the PG-degraded cartilage significantly (p < 0.01) decreased in comparison with healthy cartilage (3.46 ± 0.49%). The histological sections demonstrated that almost PG content in the entire cartilage layer was digested by trypsin. CONCLUSION Using high-frequency ultrasound, this study found a reduction in the hydration behaviour of the PG-degraded cartilage. The results indicated that the degradation of PG decreased the hydration capability of the dehydrated tissue. This study may provide useful information for further study on changes in the biomechanical property of articular cartilage in osteoarthritis.
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Affiliation(s)
- Qing Wang
- Institute of Medical Information, School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China.
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Wang Q, Zheng YP. Ultrasound assessment of boundary effect on osmosis-induced shrinkage and swelling of articular cartilage in vitro. Connect Tissue Res 2013; 54:153-8. [PMID: 23216088 DOI: 10.3109/03008207.2012.756872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This study aims to use ultrasound to investigate the boundary effect of the cut edge on the osmosis-induced shrinkage and swelling of articular cartilage while the distance from the scanning site to the edge decreases with the reduction of specimen size. Sixteen cartilage-bone specimens (of diameter 6.35 mm) were prepared from normal bovine patellae. The cartilage width was gradually reduced to 4.35 mm and to 2.35 mm. Shrinkage and swelling were induced by changing the concentration of the saline solution and monitored using nominal 50 MHz focused ultrasound. The parameters including shrinkage and swelling peak strains (ϵ(P1) and ϵ(P2), respectively), shrinkage and swelling equilibrium strains (ϵ(E1) and ϵ(E2), respectively), and shrinkage and swelling slopes (k(1) and k(2), respectively) were extracted. The ϵ(P1), ϵ(E1), ϵ(E2), k(1), and k(2) of the 2.35 mm specimens were significantly different (p < 0.05) from those of the 6.35 mm specimens. For the 4.35 mm specimens, ϵ(E1) and ϵ(P1) were, respectively, significantly different (p < 0.05) from ϵ(E1) of the 6.35 mm specimens and ϵ(P1) of the 2.35 mm specimens. The percentage of coefficient of variation (18.5% for shrinkage and 16.3% for swelling) of the 2.35 mm specimens was much higher than that (<8.5%) of the 6.35 mm specimens. The relative root mean square difference (rRMSD%, 12.0% for shrinkage and 10.6% for swelling) of the 2.35 mm specimens was also much higher than that (<5.5%) of the 6.35 mm specimens. The results indicated that the boundary effect of the cut edge on the osmosis-induced shrinkage and swelling of articular cartilage increases with the reduction of specimen size.
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Affiliation(s)
- Qing Wang
- Institute of Medical Information, School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
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Silvast TS, Jurvelin JS, Tiitu V, Quinn TM, Töyräs J. Bath Concentration of Anionic Contrast Agents Does Not Affect Their Diffusion and Distribution in Articular Cartilage In Vitro. Cartilage 2013; 4:42-51. [PMID: 26069649 PMCID: PMC4297109 DOI: 10.1177/1947603512451023] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Differences in contrast agent diffusion reflect changes in composition and structure of articular cartilage. However, in clinical application the contrast agent concentration in the joint capsule varies, which may affect the reliability of contrast enhanced cartilage tomography (CECT). In the present study, effects of concentration of x-ray contrast agents on their diffusion and equilibrium distribution in cartilage were investigated. DESIGN Full-thickness cartilage discs (d = 4.0 mm, n = 120) were detached from bovine patellae (n = 24). The diffusion of various concentrations of ioxaglate (5, 10, 21, 50 mM) and iodide (30, 60, 126, 300 mM) was allowed only through the articular surface. Samples were imaged with a clinical peripheral quantitative computed tomography scanner before immersion in contrast agent, and after 1, 5, 9, 16, 25, and 29 hours in the bath. RESULTS Diffusion and partition coefficients were similar between different contrast agent concentrations. The diffusion coefficient of iodide (473 ± 133 µm(2)/s) was greater (P ≤ 0.001) than that of ioxaglate (92 ± 46 µm(2)/s). In full-thickness cartilage, the partition coefficient (at 29 h) of iodide (71 ± 5%) was greater (P ≤ 0.02 with most concentrations) than that of ioxaglate (62 ± 6%). CONCLUSIONS Significant differences in partition and diffusion coefficient of two similarly charged (-1) contrast agents were detected, which shows the effect of steric interactions. However, the increase in solute concentration did not increase its partition coefficient. In clinical application, it is important that contrast agent concentration does not affect the interpretation of CECT imaging.
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Affiliation(s)
- Tuomo S. Silvast
- SIB-Labs, University of Eastern Finland, Kuopio, Finland,Department of Applied Physics, University of Eastern Finland, Kuopio, Finland,Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
| | - Jukka S. Jurvelin
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Virpi Tiitu
- Institute of Biomedicine, Anatomy, University of Eastern Finland, Kuopio, Finland
| | - Thomas M. Quinn
- Department of Chemical Engineering, McGill University, Montreal, Canada
| | - Juha Töyräs
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland,Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
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Zheng YP, Wang Q, Butt YKC. Real-time electro-mechano-acoustic imaging for monitoring interactions between trypsin and different inhibitors in articular cartilage. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:465-473. [PMID: 21256664 DOI: 10.1016/j.ultrasmedbio.2010.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 11/25/2010] [Accepted: 12/06/2010] [Indexed: 05/30/2023]
Abstract
The purpose of this study was to observe the real-time interactions between trypsin and various inhibitors in articular cartilage in vitro using a novel electro-mechano-acoustic imaging method. Monitored in real-time, articular cartilage specimens from bovine patellae were first treated with trypsin to reach half proteoglycan depletion (Phase I), then the trypsin solution was replaced with (i) physiological saline buffer (PS), (ii) fetal bovine serum (FBS), (iii) protease inhibitor cocktail (PI) and (iv) 10% formalin (F), respectively, to observe their effects on residual digestion (Phase II). Ultrasound radio frequency signals from the articular cartilage were used to form a M-mode image, where the interface between trypsin digested and intact cartilage tissues could be observed with an additional echo generated. The inhibition time, the digestion depth and digestion fraction were measured for each specimen. The results showed that the dilution of trypsin using saline solution was not sufficient to stop the enzyme action instantly. Although groups FBS and PI had a similar inhibition time of approximately 1.5 h, their digestion depth was obviously different (0.25±0.03 and 0.06±0.06 mm, respectively). In contrast, formalin only took <30 min to stop the trypsin digestion with almost no further digestion. The results demonstrated that the current system was capable of monitoring the trypsin digestion and inhibition process in real time. Also, different chemicals affected the residual trypsin digestion to different degrees.
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Affiliation(s)
- Yong-Ping Zheng
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China.
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12
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Wang Q, Zheng YP, Wang XY, Huang YP, Liu MQ, Wang SZ, Zhang ZK, Guo X. Ultrasound evaluation of site-specific effect of simulated microgravity on articular cartilage. ULTRASOUND IN MEDICINE & BIOLOGY 2010; 36:1089-1097. [PMID: 20620696 DOI: 10.1016/j.ultrasmedbio.2010.04.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 04/21/2010] [Accepted: 04/28/2010] [Indexed: 05/29/2023]
Abstract
Space flight induces acute changes in normal physiology in response to the microgravity environment. Articular cartilage is subjected to high loads under a ground reaction force on Earth. The objectives of this study were to investigate the site dependence of morphological and ultrasonic parameters of articular cartilage and to examine the site-specific responses of articular cartilage to simulated microgravity using ultrasound biomicroscopy (UBM). Six rats underwent tail suspension (simulated microgravity) for four weeks and six other rats were kept under normal Earth gravity as controls. Cartilage thickness, ultrasound roughness index (URI), integrated reflection coefficient (IRC) and integrated backscatter coefficient (IBC) of cartilage tissues, as well as histological degeneration were measured at the femoral head (FH), medial femoral condyle (MFC), lateral femoral condyle (LFC), patello-femoral groove (PFG) and patella (PAT). The results showed site dependence not significant in all UBM parameters except cartilage thickness (p < 0.01) in the control specimens. Only minor changes in articular cartilage were induced by 4-week tail suspension, although there were significant decreases in cartilage thickness at the MFC and PAT (p < 0.05) and a significant increase in URI at the PAT (p < 0.01). This study suggested that the 4-week simulated microgravity had only mild effects on femoral articular cartilage in the rat model. This information is useful for human spaceflight and clinical medicine in improving understanding of the effect of microgravity on articular cartilage. However, the effects of longer duration microgravity experience on articular cartilage need further investigation.
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Affiliation(s)
- Qing Wang
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, China
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Wang SZ, Huang YP, Saarakkala S, Zheng YP. Quantitative assessment of articular cartilage with morphologic, acoustic and mechanical properties obtained using high-frequency ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2010; 36:512-527. [PMID: 20172450 DOI: 10.1016/j.ultrasmedbio.2009.12.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Revised: 12/05/2009] [Accepted: 12/17/2009] [Indexed: 05/28/2023]
Abstract
Osteoarthritis (OA) is one of the most common joint diseases among adults, and its early detection is still not possible. In this study, high-frequency ultrasound and ultrasound-assisted mechanical testing systems were used to quantitatively measure the morphologic, acoustic and mechanical properties of normal and enzymatically degraded bovine articular cartilages in vitro. A total of 40 osteochondral cartilage plugs were prepared from 20 bovine patellae (n=20x2) and divided into two groups for collagenase and trypsin digestions, respectively. A high-frequency ultrasound system (center frequency: 40 MHz) was used to analyze the surface integrity (ultrasound roughness index, URI), thickness and acoustic properties of the articular cartilages before and after enzymatic degradations. Acoustic parameters included the integrated reflection coefficient (IRC) from the cartilage surface, reflection from the cartilage-bone interface (AIB(bone)), integrated attenuation (IA) and integrated backscatter (IBS) of the internal cartilage tissue. A newly developed ultrasound water jet indentation system was used to assess the mechanical properties of the cartilage samples. The results showed that the URI increased significantly (p<0.05) after collagenase digestion while no significant change (p>0.05) was found after trypsin digestion. With regard to acoustic parameters, the IRC decreased significantly (p<0.05) after collagenase digestion while no significant change (p>0.05) was found after trypsin digestion. The AIB(bone) demonstrated an insignificant change after collagenase digestion (p>0.05) but a significant decrease after trypsin digestion (p<0.05). Both enzymatic degradation groups showed insignificant differences (p>0.05) in the IA but a significant increase (p<0.05) in the IBS after both enzymatic degradations. The apparent stiffness measured by ultrasound water jet indentation suggested that articular cartilage from both groups became significantly softer (p<0.05) after the enzymatic degradations. A significant relationship was found to exist between the IRC and URI (p<0.05). This study showed that high-frequency ultrasound can be a comprehensive tool to quantitatively and systematically analyze the morphologic, acoustic and mechanical properties of articular cartilage in association with its degeneration.
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Affiliation(s)
- Shu-Zhe Wang
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
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Elkin BS, Shaik MA, Morrison B. Fixed negative charge and the Donnan effect: a description of the driving forces associated with brain tissue swelling and oedema. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2010; 368:585-603. [PMID: 20047940 PMCID: PMC2944388 DOI: 10.1098/rsta.2009.0223] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cerebral oedema or brain tissue swelling is a significant complication following traumatic brain injury or stroke that can increase the intracranial pressure (ICP) and impair blood flow. Here, we have identified a potential driver of oedema: the negatively charged molecules fixed within cells. This fixed charge density (FCD), once exposed, could increase ICP through the Donnan effect. We have shown that metabolic processes and membrane integrity are required for concealing this FCD as slices of rat cortex swelled immediately (within 30 min) following dissection if treated with 2 deoxyglucose + cyanide (2DG+CN) or Triton X-100. Slices given ample oxygen and glucose, however, did not swell significantly. We also found that dead brain tissue swells and shrinks in response to changes in ionic strength of the bathing medium, which suggests that the Donnan effect is capable of pressurizing and swelling brain tissue. As predicted, a non-ionic osmolyte, 1,2 propanediol, elicited no volume change at 2000 x 10(-3) osmoles l(-1) (Osm). Swelling data were well described by triphasic mixture theory with the calculated reference state FCD similar to that measured with a 1,9 dimethylmethylene blue assay. Taken together, these data suggest that intracellular fixed charges may contribute to the driving forces responsible for brain swelling.
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Wang SZ, Huang YP, Wang Q, Zheng YP, He YH. Assessment of depth and degeneration dependences of articular cartilage refractive index using optical coherence tomography in vitro. Connect Tissue Res 2010; 51:36-47. [PMID: 20067415 DOI: 10.3109/03008200902890161] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this study, optical coherence tomography (OCT) with an axial resolution of 15 mum was used to investigate the depth and degeneration dependences of the refractive index (RI) of articular cartilage collected from bovine patellae in vitro. Eighteen disks of articular cartilage with a diameter of 6.35 mm harvested from different patellae were successfully prepared. Each disk was cut into two halves and three horizontal cartilage slices (n = 18 x 2 x 3) with an approximately equal thickness of 0.5 mm were further prepared from each half disk. The cartilage slices were digested by two different enzymes, collagenase and trypsin, to disturb collagen fibrils and proteoglycans, respectively. The samples were submerged in the physiological saline and tested using OCT before and after the enzyme digestion and the RI for each specimen was calculated. The RI of articular cartilage from the superficial to deep regions was 1.361 +/- 0.032 (mean +/- SD), 1.338 +/- 0.036, and 1.371 +/- 0.041 for normal specimens; 1.357 +/- 0.036, 1.331 +/- 0.030, and 1.392 +/- 0.037 for trypsin digested specimens; and 1.361 +/- 0.032, 1.336 +/- 0.048, and 1.376 +/- 0.043 for those treated by collagenase, respectively. Two-factor repeated measure ANOVA revealed that for all the three groups of specimens, the RI in different depths was significantly different (p < 0.05). However, we found that the trypsin and collagenase treatments did not exert a significant effect on the RI (p > 0.05). The results suggested that the depth dependence of articular cartilage should be taken into account when OCT is used for related measurement.
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Affiliation(s)
- Shu-Zhe Wang
- Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hong Kong, China
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Wang Q, Zheng YP. Ultrasound biomicroscopy imaging for monitoring progressive trypsin digestion and inhibition in articular cartilage. ULTRASOUND IN MEDICINE & BIOLOGY 2009; 35:1535-1545. [PMID: 19616365 DOI: 10.1016/j.ultrasmedbio.2009.04.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 04/17/2009] [Accepted: 04/21/2009] [Indexed: 05/28/2023]
Abstract
This study reports an ultrasound biomicroscopy (UBM) imaging approach to monitor the progressive trypsin-induced depletion of proteoglycan (PG) and its inhibition in articular cartilage. Three fresh, normal bovine patellae were obtained and four full-thickness cartilage-bone specimens were prepared from the lower medial side of each patella. One sample was used as a control and the other three were divided into three groups: Groups A, B and C (n=3 for each group). After a 40min 0.25% trypsin digestion, samples from group A were continuously digested in trypsin solution, while those in groups B and C were immersed in physiologic saline and fetal bovine serum (FBS), respectively, for another 280min. The trypsin penetration front was observed by UBM and M-mode images were acquired using 50MHz focused ultrasound and custom-developed software. The results show that the 40min trypsin digestion degraded nearly the whole surface layer of the cartilage tissue. Further digestion in trypsin or residual digestion in saline for 280min depleted most of the PG content, as observed in groups A and B. The replacement of trypsin with a physiologic saline solution only slightly slowed the digestion process (group B), while trypsin inhibitors in FBS stopped the digestion in approximately 1.5h (group C). The normalized digestion fractions of the digested tissues were calculated from ultrasound data and histology sections, and then compared between the groups. Without the use of FBS, 80% to 100% of the full thickness was digested, while this number was only approximately 50% when using FBS. Our findings indicate that the UBM imaging system could provide two-dimensional (2-D) visual information for monitoring progressive trypsin-induced PG depletion in articular cartilage. The system also potentially offers a useful tool for preparing cartilage degeneration models with precisely controlled PG depletion.
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Affiliation(s)
- Qing Wang
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, China
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Zheng YP, Huang YP. More intrinsic parameters should be used in assessing degeneration of articular cartilage with quantitative ultrasound. Arthritis Res Ther 2008; 10:125. [PMID: 19138384 PMCID: PMC2656244 DOI: 10.1186/ar2566] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
During the last decade, the quantitative ultrasound technique has been widely employed as a versatile modality to investigate a thin but crucial tissue layer – the articular cartilage. Previous studies provide information about the morphology and mechanical and acoustic properties of the tissue derived from ultrasound measurements and correlate them with cartilage degeneration. In a previous issue of Arthritis Research & Therapy, Kuroki and colleagues presented a study about the relationship between International Cartilage Repair Society grading and ultrasound echo magnitude, duration, and interval in human knee cartilage. We think indirect measurements of the intrinsic physical characteristics of cartilage, as reported in this study, should be interpreted more carefully as they can be affected by many experimental and physical factors. In this editorial, we offer our opinion that more intrinsic material parameters should be selected for the assessment of degeneration states of cartilage using quantitative ultrasound.
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