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Kupratis ME, Rahman A, Burris DL, Corbin EA, Price C. Enzymatic digestion does not compromise sliding-mediated cartilage lubrication. Acta Biomater 2024; 178:196-207. [PMID: 38428511 DOI: 10.1016/j.actbio.2024.02.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/03/2024]
Abstract
Articular cartilage's remarkable low-friction properties are essential to joint function. In osteoarthritis (OA), cartilage degeneration (e.g., proteoglycan loss and collagen damage) decreases tissue modulus and increases permeability. Although these changes impair lubrication in fully depressurized and slowly slid cartilage, new evidence suggests such relationships may not hold under biofidelic sliding conditions more representative of those encountered in vivo. Our recent studies using the convergent stationary contact area (cSCA) configuration demonstrate that articulation (i.e., sliding) generates interfacial hydrodynamic pressures capable of replenishing cartilage interstitial fluid/pressure lost to compressive loading through a mechanism termed tribological rehydration. This fluid recovery sustains in vivo-like kinetic friction coefficients (µk<0.02 in PBS and <0.005 in synovial fluid) with little sensitivity to mechanical properties in healthy tissue. However, the tribomechanical function of compromised cartilage under biofidelic sliding conditions remains unknown. Here, we investigated the effects of OA-like changes in cartilage mechanical properties, modeled via enzymatic digestion of mature bovine cartilage, on its tribomechanical function during cSCA sliding. We found no differences in sliding-driven tribological rehydration behaviors or µk between naïve and digested cSCA cartilage (in PBS or synovial fluid). This suggests that OA-like cartilage retains sufficient functional properties to support naïve-like fluid recovery and lubrication under biofidelic sliding conditions. However, OA-like cartilage accumulated greater total tissue strains due to elevated strain accrual during initial load application. Together, these results suggest that elevated total tissue strains-as opposed to activity-mediated strains or friction-driven wear-might be the key biomechanical mediator of OA pathology in cartilage. STATEMENT OF SIGNIFICANCE: Osteoarthritis (OA) decreases cartilage's modulus and increases its permeability. While these changes compromise frictional performance in benchtop testing under low fluid load support (FLS) conditions, whether such observations hold under sliding conditions that better represent the joints' dynamic FLS conditions in vivo is unclear. Here, we leveraged biofidelic benchtop sliding experiments-that is, those mimicking joints' native sliding environment-to examine how OA-like changes in mechanical properties effect cartilage's natural lubrication. We found no differences in sliding-mediated fluid recovery or kinetic friction behaviors between naïve and OA-like cartilage. However, OA-like cartilage experienced greater strain accumulation during load application, suggesting that elevated tissue strains (not friction-driven wear) may be the primary biomechanical mediator of OA pathology.
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Affiliation(s)
| | - Atia Rahman
- Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - David L Burris
- Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Elise A Corbin
- Biomedical Engineering, University of Delaware, Newark, DE, USA; Materials Science & Engineering, University of Delaware, Newark, DE, USA
| | - Christopher Price
- Biomedical Engineering, University of Delaware, Newark, DE, USA; Mechanical Engineering, University of Delaware, Newark, DE, USA.
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2
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Petersen CA, Sise CV, Dewing JX, Yun J, Zimmerman BK, Guo XE, Hung CT, Ateshian GA. Immature bovine cartilage wear is due to fatigue failure from repetitive compressive forces and not reciprocating frictional forces. Osteoarthritis Cartilage 2023; 31:1594-1601. [PMID: 37633593 PMCID: PMC10841040 DOI: 10.1016/j.joca.2023.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 08/28/2023]
Abstract
OBJECTIVE Wear of articular cartilage is not well understood. We hypothesize that cartilage wears due to fatigue failure in repetitive compression instead of reciprocating friction. DESIGN This study compares reciprocating sliding of immature bovine articular cartilage against glass in two testing configurations: (1) a stationary contact area configuration (SCA), which results in static compression, interstitial fluid depressurization, and increasing friction coefficient during reciprocating sliding, and (2) a migrating contact area configuration (MCA), which maintains pressurization and low friction while producing repetitive compressive loading in addition to reciprocating sliding. Contact pressure, sliding duration, and sliding distance were controlled to be similar between test groups. RESULTS SCA tests exhibited an average friction coefficient of μ=0.084±0.032, while MCA tests exhibited a lower average friction coefficient of μ=0.020±0.008 (p<10-4). Despite the lower friction, MCA cartilage samples exhibited clear surface damage with a significantly greater average surface deviation from a fitted plane after wear testing (Rq=0.125±0.095 mm) than cartilage samples slid in a SCA configuration (Rq=0.044±0.017 mm, p=0.002), which showed minimal signs of wear. Polarized light microscopy confirmed that delamination damage occurred between the superficial and middle zones of the articular cartilage in MCA samples. CONCLUSIONS The greatest wear was observed in the group with lowest friction coefficient, subjected to cyclical instead of static compression, implying that friction is not the primary driver of cartilage wear. Delamination between superficial and middle zones implies the main mode of wear is fatigue failure under cyclical compression, not fatigue or abrasion due to reciprocating frictional sliding.
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Affiliation(s)
- C A Petersen
- Department of Mechanical Engineering, Columbia University, New York, NY, United States
| | - C V Sise
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - J X Dewing
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - J Yun
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - B K Zimmerman
- Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - X E Guo
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - C T Hung
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - G A Ateshian
- Department of Mechanical Engineering, Columbia University, New York, NY, United States; Department of Biomedical Engineering, Columbia University, New York, NY, United States.
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3
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Demott C, Jones MR, Chesney CD, Grunlan MA. Adhesive Hydrogel Building Blocks to Reconstruct Complex Cartilage Tissues. ACS Biomater Sci Eng 2023; 9:1952-1960. [PMID: 36881710 PMCID: PMC10848198 DOI: 10.1021/acsbiomaterials.2c01438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 02/14/2023] [Indexed: 03/09/2023]
Abstract
Cartilage has an intrinsically low healing capacity, thereby requiring surgical intervention. However, limitations of biological grafting and existing synthetic replacements have prompted the need to produce cartilage-mimetic substitutes. Cartilage tissues perform critical functions that include load bearing and weight distribution, as well as articulation. These are characterized by a range of high moduli (≥1 MPa) as well as high hydration (60-80%). Additionally, cartilage tissues display spatial heterogeneity, resulting in regional differences in stiffness that are paramount to biomechanical performance. Thus, cartilage substitutes would ideally recapitulate both local and regional properties. Toward this goal, triple network (TN) hydrogels were prepared with cartilage-like hydration and moduli as well as adhesivity to one another. TNs were formed with either an anionic or cationic 3rd network, resulting in adhesion upon contact due to electrostatic attractive forces. With the increased concentration of the 3rd network, robust adhesivity was achieved as characterized by shear strengths of ∼80 kPa. The utility of TN hydrogels to form cartilage-like constructs was exemplified in the case of an intervertebral disc (IVD) having two discrete but connected zones. Overall, these adhesive TN hydrogels represent a potential strategy to prepare cartilage substitutes with native-like regional properties.
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Affiliation(s)
- Connor
J. Demott
- Department
of Biomedical Engineering, Texas A&M
University, College
Station, Texas 77843-3003, United States
| | - McKenzie R. Jones
- Department
of Biomedical Engineering, Texas A&M
University, College
Station, Texas 77843-3003, United States
| | - Caleb D. Chesney
- Department
of Biomedical Engineering, Texas A&M
University, College
Station, Texas 77843-3003, United States
| | - Melissa A. Grunlan
- Department
of Biomedical Engineering, Texas A&M
University, College
Station, Texas 77843-3003, United States
- Department
of Materials Science & Engineering, Texas A&M University, College
Station, Texas 77843-3003, United States
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843-3003, United States
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4
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Locke RC, Zlotnick HM, Stoeckl BD, Fryhofer GW, Galarraga JH, Dhand AP, Zgonis MH, Carey JL, Burdick JA, Mauck RL. Linguistic Analysis Identifies Emergent Biomaterial Fabrication Trends for Orthopaedic Applications. Adv Healthc Mater 2023; 12:e2202591. [PMID: 36657736 PMCID: PMC10121863 DOI: 10.1002/adhm.202202591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 12/20/2022] [Indexed: 01/21/2023]
Abstract
The expanse of publications in tissue engineering (TE) and orthopedic TE (OTE) over the past 20 years presents an opportunity to probe emergent trends in the field to better guide future technologies that can make an impact on musculoskeletal therapies. Leveraging this trove of knowledge, a hierarchical systematic search method and trend analysis using connected network mapping of key terms is developed. Within discrete time intervals, an accelerated publication rate for anatomic orthopedic tissue engineering (AOTE) of osteochondral defects, tendons, menisci, and entheses is identified. Within these growing fields, the top-listed key terms are extracted and stratified into evident categories, such as biomaterials, delivery method, or 3D printing and biofabrication. It is then identified which categories decreased, remained constant, increased, or emerged over time, identifying the specific emergent categories currently driving innovation in orthopedic repair technologies. Together, these data demonstrate a significant convergence of material types and descriptors used across tissue types. From this convergence, design criteria to support future research of anatomic constructs that mimic both the form and function of native tissues are formulated. In summary, this review identifies large-scale trends and predicts new directions in orthopedics that will define future materials and technologies.
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Affiliation(s)
- Ryan C. Locke
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
- Department of Veterans Affairs, CMCVAMC, Philadelphia, PA, USA
| | - Hannah M. Zlotnick
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
- Department of Veterans Affairs, CMCVAMC, Philadelphia, PA, USA
| | - Brendan D. Stoeckl
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
- Department of Veterans Affairs, CMCVAMC, Philadelphia, PA, USA
| | - George W. Fryhofer
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Abhishek P. Dhand
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Miltiadis H. Zgonis
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - James L. Carey
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Jason A. Burdick
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, USA
- BioFrontiers Institute, University of Colorado, Boulder, CO, USA
| | - Robert L. Mauck
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
- Department of Veterans Affairs, CMCVAMC, Philadelphia, PA, USA
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5
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Demott CJ, Grunlan MA. Emerging polymeric material strategies for cartilage repair. J Mater Chem B 2022; 10:9578-9589. [PMID: 36373438 DOI: 10.1039/d2tb02005j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cartilage is found throughout the body, serving an array of essential functions. Owing to the limited healing capacity of cartilage, damage or degeneration is often permanent and so requires clinical intervention. Established surgical techniques generally rely on biological grafting. However, recent advances in polymeric materials provide an encouraging alternative to overcome limits of auto- and allografts. For regenerative engineering of cartilage, a polymeric scaffold ideally supports and instructs tissue regeneration while also providing mechanical integrity. Scaffolds direct regeneration via chemical and mechanical cues, as well as delivery and support of exogenous cells and bioactive factors. Advanced polymeric scaffolds aim to direct regeneration locally, replicating the heterogeneities of native tissues. Alternatively, new cartilage-mimetic hydrogels have potential to serve as synthetic cartilage replacements. Prepared as multi-network or composite hydrogels, the most promising candidates have simultaneously realized the hydration, mechanical, and tribological properties of native cartilage. Collectively, the recent rise in polymers for cartilage regeneration and replacement proposes a changing paradigm, with a new generation of materials paving the way for improved clinical outcomes.
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Affiliation(s)
- Connor J Demott
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843-3003, USA
| | - Melissa A Grunlan
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843-3003, USA.,Department of Materials Science & Engineering, Texas A&M University, College Station, TX 77843-3003, USA.,Department of Chemistry, Texas A&M University, College Station, TX 77843-3003, USA.
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6
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Demott CJ, Jones MR, Chesney CD, Yeisley DJ, Culibrk RA, Hahn MS, Grunlan MA. Ultra-High Modulus Hydrogels Mimicking Cartilage of the Human Body. Macromol Biosci 2022; 22:e2200283. [PMID: 36040017 DOI: 10.1002/mabi.202200283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/12/2022] [Indexed: 12/25/2022]
Abstract
The human body is comprised of numerous types of cartilage with a range of high moduli, despite their high hydration. Owing to the limitations of cartilage tissue healing and biological grafting procedures, synthetic replacements have emerged but are limited by poorly matched moduli. While conventional hydrogels can achieve similar hydration to cartilage tissues, their moduli are substantially inferior. Herein, triple network (TN) hydrogels are prepared to synergistically leverage intra-network electrostatic repulsive and hydrophobic interactions, as well as inter-network electrostatic attractive interactions. They are comprised of an anionic 1st network, a neutral 2nd network (capable of hydrophobic associations), and a cationic 3rd network. Collectively, these interactions act synergistically as effective, yet dynamic crosslinks. By tuning the concentration of the cationic 3rd network, these TN hydrogels achieve high moduli of ≈1.5 to ≈3.5 MPa without diminishing cartilage-like water contents (≈80%), strengths, or toughness values. This unprecedented combination of properties poises these TN hydrogels as cartilage substitutes in applications spanning articulating joints, intervertebral discs (IVDs), trachea, and temporomandibular joint disc (TMJ).
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Affiliation(s)
- Connor J Demott
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3003, USA
| | - McKenzie R Jones
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3003, USA
| | - Caleb D Chesney
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3003, USA
| | - Daniel J Yeisley
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180-3590, USA
| | - Robert A Culibrk
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180-3590, USA
| | - Mariah S Hahn
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180-3590, USA
| | - Melissa A Grunlan
- Department of Biomedical Engineering, Department of Materials Science & Engineering, and Department of Chemistry, Texas A&M University, College Station, TX, 77843-3003, USA
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7
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Kupratis ME, Gure AE, Benson JM, Ortved KF, Burris DL, Price C. Comparative tribology II-Measurable biphasic tissue properties have predictable impacts on cartilage rehydration and lubricity. Acta Biomater 2022; 138:375-389. [PMID: 34728427 DOI: 10.1016/j.actbio.2021.10.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 11/16/2022]
Abstract
Healthy articular cartilage supports load bearing and frictional properties unmatched among biological tissues and man-made bearing materials. Balancing fluid exudation and recovery under loaded and articulated conditions is essential to the tissue's biological and mechanical longevity. Our prior tribological investigations, which leveraged the convergent stationary contact area (cSCA) configuration, revealed that sliding alone can modulate cartilage interstitial fluid pressurization and the recovery and maintenance of lubrication under load through a mechanism termed 'tribological rehydration.' Our recent comparative assessment of tribological rehydration revealed remarkably consistent sliding speed-dependent fluid recovery and lubrication behaviors across femoral condyle cartilage from five mammalian species (equine/horse, bovine/cow, porcine/pig, ovine/sheep, and caprine/goat). In the present study, we identified and characterized key predictive relationships among tissue properties, sliding-induced tribological rehydration, and the modulation/recovery of lubrication within healthy articular cartilage. Using correlational analysis, we linked observed speed-dependent tribological rehydration behaviors to cartilage's geometry and biphasic properties (tensile and compressive moduli, and permeability). Together, these findings demonstrate that easily measurable biphasic tissue characteristics (e.g., bulk tissue material properties, compressive strain magnitude, and strain rates) can be used to predict cartilage's rehydration and lubricating abilities, and ultimately its function in vivo. STATEMENT OF SIGNIFICANCE: In healthy cartilage, articulation recovers fluid lost to static loading thereby sustaining tissue lubricity. Osteoarthritis causes changes to cartilage composition, stiffness, and permeability associated with faster fluid exudation and presumably poorer frictional outcomes. Yet, the relationship between mechanical properties and fluid recovery during articulation/sliding remains unclear. Through innovative, high-speed benchtop sliding and indentation experiments, we found that cartilage's tissue properties regulate its exudation/hydration under slow sliding speeds but have minimal effect at high sliding speeds. In fact, cartilage rehydration appears insensitive to permeability and stiffness under high fluid load support conditions. This new understanding of the balance of cartilage exudation and rehydration during activity, based upon comparative tribology studies, may improve prevention and rehabilitation strategies for joint injuries and osteoarthritis.
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Affiliation(s)
- Meghan E Kupratis
- Biomedical Engineering, University of Delaware, Newark, Delaware, USA
| | - Ahmed E Gure
- Biomedical Engineering, University of Delaware, Newark, Delaware, USA
| | - Jamie M Benson
- Biomedical Engineering, University of Delaware, Newark, Delaware, USA
| | - Kyla F Ortved
- Clinical Studies, New Bolton Center, University of Pennsylvania School of Veterinary Medicine, Kennett Square, Pennsylvania, USA
| | - David L Burris
- Biomedical Engineering, University of Delaware, Newark, Delaware, USA; Mechanical Engineering, University of Delaware, Newark, Delaware, USA
| | - Christopher Price
- Biomedical Engineering, University of Delaware, Newark, Delaware, USA; Mechanical Engineering, University of Delaware, Newark, Delaware, USA.
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8
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Sun Y, Wang N, Yu J, Yan Y, Dong H, Wu X, Zhang M, Wang Y, Li P, Wei X, Chen W. Study on the poroelastic behaviors of the defected articular cartilage. Comput Methods Biomech Biomed Engin 2021; 25:1288-1300. [PMID: 34807804 DOI: 10.1080/10255842.2021.2007376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
This article presented the possible mechanism of arthritis damaged changes in cartilage's interstitial fluid flowing behavior. Firstly, the analytical solutions for the pore fluid pressure and velocity in the idealized cartilage defect model were obtained, which are employed to validate the finite element (FE) method. Then according to the MRI data, an articular cartilage FE model was developed to study the effects of defect characteristics on its poroelastic behaviors. The results showed the interstitial fluid pressure and velocity in defected articular cartilage is diminished, moreover, this trend is even more severe as the defect radius or thickness increased. As the development of osteoarthritis goes, the fluid velocity is decreased and cause the even serious nutrients loss.
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Affiliation(s)
- Yuqin Sun
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Ningning Wang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Jianhao Yu
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Yang Yan
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Hao Dong
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Xiaogang Wu
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Meizhen Zhang
- College of Physical Education, Taiyuan University of Technology, Taiyuan, China
| | - Yanqin Wang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Pengcui Li
- Shanxi Provincial Key Laboratory for Repair of Bone and Soft Tissue Injury, Taiyuan, China
| | - Xiaochun Wei
- Shanxi Provincial Key Laboratory for Repair of Bone and Soft Tissue Injury, Taiyuan, China
| | - Weiyi Chen
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
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9
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Culliton KN, Speirs AD. Sliding contact accelerates solute transport into the cartilage surface compared to axial loading. Osteoarthritis Cartilage 2021; 29:1362-1369. [PMID: 34082132 DOI: 10.1016/j.joca.2021.05.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 05/14/2021] [Accepted: 05/25/2021] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The objectives of this study were: first, to compare solute uptake driven by sliding to cyclic uniaxial compression. And secondly, to evaluate the role of the superficial region on passive diffusion to determine if mechanical action is merely overcoming the low permeability of the superficial region or exceeding equilibrium capacity of the tissue. DESIGN Tests were performed on osteochondral plugs under two types of conditions: cyclic loading (sliding vs axial compression) and unloaded passive diffusion (intact vs superficial zone removed). The articular surfaces were exposed to a fluorescent bath and uptake was quantified from the surface to the subchondral bone using fluorescent microscopy. Primary outcome measures were total mass transfer, mass transfer rate, and surface partition factor. RESULTS Mass transfer was 2.1-fold higher at 0.5 h for sliding compared to uniaxial compression (p = 0.004). This increased to 4.4-fold at 2 h (p = 0.002). Solute transport for both loading conditions at 2 h had reached or exceeded intact passive diffusion at 12 h. Total mass transport and mass transport per hour was higher in samples without the superficial region compared to intact samples at equilibrium. Rate of mass transfer was not declining for samples subject to sliding indicating solute uptake induced by sliding would exceed passive tissue capacity. CONCLUSIONS These results are the first to quantify solute uptake between two components of joint articulation. The study demonstrates that sliding is a larger driver of solute transport compared to cyclic uniaxial compression. This has implications for cell nutrition, tissue engineering and biochemical signaling.
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Affiliation(s)
- K N Culliton
- Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, Canada
| | - A D Speirs
- Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, Canada.
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10
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Articular Cartilage Friction, Strain, and Viability Under Physiological to Pathological Benchtop Sliding Conditions. Cell Mol Bioeng 2021; 14:349-363. [PMID: 34295444 DOI: 10.1007/s12195-021-00671-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/06/2021] [Indexed: 10/21/2022] Open
Abstract
In vivo, articular cartilage is exceptionally resistant to wear, damage, and dysfunction. However, replicating cartilage's phenomenal in vivo tribomechanics (i.e., high fluid load support, low frictions and strains) and mechanobiology on the benchtop has been difficult, because classical testing approaches tend to minimize hydrodynamic contributors to tissue function. Our convergent stationary contact area (cSCA) configuration retains the ability for hydrodynamically-mediated processes to contribute to interstitial hydration recovery and tribomechanical function via 'tribological rehydration'. Using the cSCA, we investigated how in situ chondrocyte survival is impacted by the presence of tribological rehydration during the reciprocal sliding of a glass counterface against a compressively loaded equine cSCA cartilage explant. When tribological rehydration was compromised during testing, by slow-speed sliding, 'pathophysiological' tribomechanical environments and high surface cell death were observed. When tribological rehydration was preserved, by high-speed sliding, 'semi-physiological' sliding environments and suppressed cell death were realized. Inclusion of synovial fluid during testing fostered 'truly physiological' sliding outcomes consistent with the in vivo environment but had limited influence on cell death compared to high-speed sliding in PBS. Subsequently, path analysis identified friction as a primary driver of cell death, with strain an indirect driver, supporting the contention that articulation mediated rehydration can benefit both the biomechanical properties and biological homeostasis of cartilage. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-021-00671-2.
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11
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Putignano C, Burris D, Moore A, Dini D. Cartilage rehydration: The sliding-induced hydrodynamic triggering mechanism. Acta Biomater 2021; 125:90-99. [PMID: 33676047 DOI: 10.1016/j.actbio.2021.02.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 10/22/2022]
Abstract
Loading-induced cartilage exudation causes loss of fluid from the tissue, joint space thinning and, in a long term prospective, the insurgence of osteoarthritis. Fortunately, experiments show that joints recover interstitial fluid and thicken during articulation after static loading, thus reversing the exudation process. Here, we provide the first original theoretical explanation to this crucial phenomenon, by implementing a numerical model capable of accounting for the multiscale porous lubrication occurring in joints. We prove that sliding-induced rehydration occurs because of hydrodynamic reasons and is specifically related to a wedge effect at the contact inlet. Furthermore, numerically predicted rehydration rates are consistent with experimentally measured rates and corroborate the robustness of the model here proposed. The paper provides key information, in terms of fundamental lubrication multiscale mechanisms, to understand the rehydration of cartilage and, more generally, of any biological tissue exhibiting a significant porosity: such a theoretical framework is, thus, crucial to inform the design of new effective cartilage-mimicking biomaterials. STATEMENT OF SIGNIFICANCE: Motion and, precisely, joints articulation ensures that cartilage tissues preserve adequate level of hydration and, thus, maintain excellent mechanical properties in terms of high resilience, considerable load-carrying capacity and remarkably low friction. Conversely, when statically loaded, cartilage starts to exudate, causing joint space thinning and, in the long term, possible osteoarthritis; joints motion is, thus, the key to prevent the degradation of the tissues. By developing a numerical multiscale lubrication theory, and by corroborating this approach with experiments, we provide the first original theoretical explanation to this motion-induced cartilage rehydration mechanism. Assessing the rehydration hydrodynamic origin is, in fact, fundamental not only to understand the joints physiology, but also to highlight a key requirement for cartilage-mimicking biomaterials.
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12
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Kupratis ME, Gure A, Ortved KF, Burris DL, Price C. Comparative Tribology: Articulation-induced rehydration of cartilage across species. BIOTRIBOLOGY (OXFORD) 2021; 25:100159. [PMID: 37780679 PMCID: PMC10540460 DOI: 10.1016/j.biotri.2020.100159] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Articular cartilage is a robust tissue that facilitates load distribution and wear-free articulation in diarthrodial joints. These biomechanical capabilities are fundamentally tied to tissue hydration, whereby high interstitial fluid pressures and fluid load support facilitate the maintenance of low tissue strains and frictions. Our recent ex vivo studies of cartilage sliding biomechanics using the convergent stationary contact area (cSCA) configuration, first introduced by Dowson and colleagues, unexpectedly demonstrated that sliding alone can promote recovery of interstitial pressure and lubrication lost to static compression through a mechanism termed 'tribological rehydration.' Although exclusively examined in bovine stifle cartilage to date, we hypothesized that tribological rehydration, i.e., the ability to recover/modulate tissue strains and lubrication through sliding, is a universal behavior of articular cartilage. This study aimed to establish if, and to what extent, sliding-induced tribological rehydration is conserved in articular cartilage across a number of preclinical animal species/models and diarthrodial joints. Using a comparative approach, we found that articular cartilage from equine, bovine, ovine, and caprine stifles, and porcine stifle, hip, and tarsal joints all exhibited remarkably consistent sliding speed-dependent compression/strain recovery and lubrication behaviors under matched contact stresses (0.25 MPa). All cartilage specimens tested supported robust, tribological rehydration during high-speed sliding (>30 mm/s), which as a result of competitive recovery of interstitial lubrication, promoted remarkable decreases in kinetic friction during continuous sliding. The conservation of tribological rehydration across mammalian quadruped articular cartilage suggests that sliding-induced recovery of interstitial hydration represents an important tissue adaptation and largely understudied contributor to the biomechanics of cartilage and joints.
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Affiliation(s)
| | - Ahmed Gure
- Bioengineering, University of Texas Arlington
| | - Kyla F. Ortved
- Clinical Studies, New Bolton Center, University of Pennsylvania
| | - David L. Burris
- Biomedical Engineering, University of Delaware
- Mechanical Engineering, University of Delaware
| | - Christopher Price
- Biomedical Engineering, University of Delaware
- Mechanical Engineering, University of Delaware
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Transient stiffening of cartilage during joint articulation: A microindentation study. J Mech Behav Biomed Mater 2020; 113:104113. [PMID: 33032010 DOI: 10.1016/j.jmbbm.2020.104113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 08/23/2020] [Accepted: 09/24/2020] [Indexed: 11/21/2022]
Abstract
As a mechanoactive tissue, articular cartilage undergoes compression and shear on a daily basis. With the advent of high resolution and sensitive mechanical testing methods, such as micro- and nanoindentation, it has become possible to assess changes in small-scale mechanical properties due to compression and shear of the tissue. However, investigations on the changes of these properties before and after joint articulation have been limited. To simulate articular loading of cartilage in the context of human gait, a previously developed bioreactor system was used. Immediately after bioreactor testing, the stiffness was measured using microindentation. Specifically, we investigated whether the mechanical response of the tissue was transient or permanent, dependent on counterface material, and an effect limited to the superficial zone of cartilage. We found that cartilage surface stiffness increases immediately after articular loading and returns to baseline values within 3 hr. Cartilage-on-cartilage stiffening was found to be higher compared to both alumina- and cobalt chromium-on-cartilage stiffening, which were not significantly different from each other. This stiffening response was found to be unique to the superficial zone, as articular loading on cartilage with the superficial zone removed showed no changes in stiffness. The findings of this study suggest that the cartilage superficial zone may adapt its stiffness as a response to articular loading. As the superficial zone is often compromised during the course of osteoarthritic disease, this finding is of clinical relevance, suggesting that the load-bearing function deteriorates over time.
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Graham BT, Moore AC, Burris DL, Price C. Detrimental effects of long sedentary bouts on the biomechanical response of cartilage to sliding. Connect Tissue Res 2020; 61:375-388. [PMID: 31910694 DOI: 10.1080/03008207.2019.1673382] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purpose/Aim: Epidemiological evidence suggests, contrary to popular mythos, that increased exercise/joint activity does not place articular cartilage at increased risk of disease, but instead promotes joint health. One explanation for this might be activity-induced cartilage rehydration; where joint articulation drives restoration of tissue hydration, thickness, and dependent tribomechanical outcomes (e.g., load support, stiffness, and lubricity) lost to joint loading. However, there have been no studies investigating how patterning of intermittent articulation influences the hydration and biomechanical functions of cartilage.Materials and Methods: Here we leveraged the convergent stationary contact area (cSCA) testing configuration and its unique ability to drive tribological rehydration, to elucidate how intermittency of activity affects the biomechanical functions of bovine stifle cartilage under well-controlled sliding conditions that have been designed to model a typical "day" of human joint activity.Results: For a fixed volume of "daily" activity (30 min) and sedentary time (60 min), breaking up intermittent activity into longer and less-frequent bouts (corresponding to longer continuous sedentary periods) resulted in the exposure of articular cartilage to markedly greater strains, losses of interstitial pressure, and friction coefficients.Conclusions: These results demonstrated that the regularity of ex vivo activity regimens, specifically the duration of sedentary bouts, had a dominant effect on the biomechanical functions of articular cartilage. In more practical terms, the results suggest that brief but regular movement patterns (e.g., every hour) may be biomechanically preferred to long and infrequent movement patterns (e.g., a long walk after a sedentary day) when controlling for daily activity volume (e.g., 30 min).
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Affiliation(s)
- Brian T Graham
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Axel C Moore
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - David L Burris
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA.,Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Christopher Price
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA.,Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
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Riemenschneider PE, Rose MD, Giordani M, McNary SM. Compressive fatigue and endurance of juvenile bovine articular cartilage explants. J Biomech 2019; 95:109304. [DOI: 10.1016/j.jbiomech.2019.07.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 11/24/2022]
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Orozco GA, Tanska P, Florea C, Grodzinsky AJ, Korhonen RK. A novel mechanobiological model can predict how physiologically relevant dynamic loading causes proteoglycan loss in mechanically injured articular cartilage. Sci Rep 2018; 8:15599. [PMID: 30348953 PMCID: PMC6197240 DOI: 10.1038/s41598-018-33759-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/02/2018] [Indexed: 12/13/2022] Open
Abstract
Cartilage provides low-friction properties and plays an essential role in diarthrodial joints. A hydrated ground substance composed mainly of proteoglycans (PGs) and a fibrillar collagen network are the main constituents of cartilage. Unfortunately, traumatic joint loading can destroy this complex structure and produce lesions in tissue, leading later to changes in tissue composition and, ultimately, to post-traumatic osteoarthritis (PTOA). Consequently, the fixed charge density (FCD) of PGs may decrease near the lesion. However, the underlying mechanisms leading to these tissue changes are unknown. Here, knee cartilage disks from bovine calves were injuriously compressed, followed by a physiologically relevant dynamic compression for twelve days. FCD content at different follow-up time points was assessed using digital densitometry. A novel cartilage degeneration model was developed by implementing deviatoric and maximum shear strain, as well as fluid velocity controlled algorithms to simulate the FCD loss as a function of time. Predicted loss of FCD was quite uniform around the cartilage lesions when the degeneration algorithm was driven by the fluid velocity, while the deviatoric and shear strain driven mechanisms exhibited slightly discontinuous FCD loss around cracks. Our degeneration algorithm predictions fitted well with the FCD content measured from the experiments. The developed model could subsequently be applied for prediction of FCD depletion around different cartilage lesions and for suggesting optimal rehabilitation protocols.
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Affiliation(s)
- Gustavo A Orozco
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - Petri Tanska
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Cristina Florea
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
- Departments of Biological Engineering, Electrical Engineering and Computer Science and Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Alan J Grodzinsky
- Departments of Biological Engineering, Electrical Engineering and Computer Science and Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Rami K Korhonen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
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