1
|
Patterson F, Miralami R, Tansey KE, Prabhu RK, Priddy LB. Deleterious effects of whole-body vibration on the spine: A review of in vivo, ex vivo, and in vitro models. Animal Model Exp Med 2021; 4:77-86. [PMID: 34179716 PMCID: PMC8212824 DOI: 10.1002/ame2.12163] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/19/2021] [Indexed: 12/19/2022] Open
Abstract
Occupational exposure to whole-body vibration is associated with the development of musculoskeletal, neurological, and other ailments. Low back pain and other spine disorders are prevalent among those exposed to whole-body vibration in occupational and military settings. Although standards for limiting exposure to whole-body vibration have been in place for decades, there is a lack of understanding of whole-body vibration-associated risks among safety and healthcare professionals. Consequently, disorders associated with whole-body vibration exposure remain prevalent in the workforce and military. The relationship between whole-body vibration and low back pain in humans has been established largely through cohort studies, for which vibration inputs that lead to symptoms are rarely, if ever, quantified. This gap in knowledge highlights the need for the development of relevant in vivo, ex vivo, and in vitro models to study such pathologies. The parameters of vibrational stimuli (eg, frequency and direction) play critical roles in such pathologies, but the specific cause-and-effect relationships between whole-body vibration and spinal pathologies remain mostly unknown. This paper provides a summary of whole-body vibration parameters; reviews in vivo, ex vivo, and in vitro models for spinal pathologies resulting from whole-body vibration; and offers suggestions to address the gaps in translating injury biomechanics data to inform clinical practice.
Collapse
Affiliation(s)
- Folly Patterson
- Department of Agricultural and Biological EngineeringMississippi State UniversityMississippi StateMSUSA
- Center for Advanced Vehicular SystemsMississippi State UniversityStarkvilleMSUSA
| | - Raheleh Miralami
- Center for Advanced Vehicular SystemsMississippi State UniversityStarkvilleMSUSA
| | - Keith E. Tansey
- Department of Neurosurgery and NeurobiologyUniversity of Mississippi Medical CenterJacksonMSUSA
- Center for Neuroscience and Neurological RecoveryMethodist Rehabilitation CenterJacksonMSUSA
- Spinal Cord Injury Medicine and Research ServicesG.V. (Sonny) Montgomery VA Medical CenterJacksonMSUSA
| | - Raj K. Prabhu
- Department of Agricultural and Biological EngineeringMississippi State UniversityMississippi StateMSUSA
- Center for Advanced Vehicular SystemsMississippi State UniversityStarkvilleMSUSA
| | - Lauren B. Priddy
- Department of Agricultural and Biological EngineeringMississippi State UniversityMississippi StateMSUSA
- Center for Advanced Vehicular SystemsMississippi State UniversityStarkvilleMSUSA
| |
Collapse
|
2
|
Shah BS, Chahine NO. Dynamic Hydrostatic Pressure Regulates Nucleus Pulposus Phenotypic Expression and Metabolism in a Cell Density-Dependent Manner. J Biomech Eng 2019; 140:2666887. [PMID: 29247254 DOI: 10.1115/1.4038758] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Indexed: 11/08/2022]
Abstract
Dynamic hydrostatic pressure (HP) loading can modulate nucleus pulposus (NP) cell metabolism, extracellular matrix (ECM) composition, and induce transformation of notochordal NP cells into mature phenotype. However, the effects of varying cell density and dynamic HP magnitude on NP phenotype and metabolism are unknown. This study examined the effects of physiological magnitudes of HP loading applied to bovine NP cells encapsulated within three-dimensional (3D) alginate beads. Study 1: seeding density (1 M/mL versus 4 M/mL) was evaluated in unloaded and loaded (0.1 MPa, 0.1 Hz) conditions. Study 2: loading magnitude (0, 0.1, and 0.6 MPa) applied at 0.1 Hz to 1 M/mL for 7 days was evaluated. Study 1: 4 M/mL cell density had significantly lower adenosine triphosphate (ATP), glycosaminoglycan (GAG) and collagen content, and increased lactate dehydrogenase (LDH). HP loading significantly increased ATP levels, and expression of aggrecan, collagen I, keratin-19, and N-cadherin in HP loaded versus unloaded groups. Study 2: aggrecan expression increased in a dose dependent manner with HP magnitude, whereas N-cadherin and keratin-19 expression were greatest in low HP loading compared to unloaded. Overall, the findings of the current study indicate that cell seeding density within a 3D construct is a critical variable influencing the mechanobiological response of NP cells to HP loading. NP mechanobiology and phenotypic expression was also found to be dependent on the magnitude of HP loading. These findings suggest that HP loading and culture conditions of NP cells may require complex optimization for engineering an NP replacement tissue.
Collapse
Affiliation(s)
- Bhranti S Shah
- Department of Orthopedic Surgery, Columbia University, New York, NY 10032
| | - Nadeen O Chahine
- Department of Orthopedic Surgery, Columbia University, 650 West 168th Street, 14-1408E, New York, NY 10032.,Department of Biomedical Engineering, Columbia University, New York, NY 10032 e-mail:
| |
Collapse
|
3
|
Abstract
Purpose of review The endplates form the interface between the rigid vertebral bodies and compliant intervertebral discs. Proper endplate function involves a balance between conflicting biomechanical and nutritional demands. This review summarizes recent data that highlight the importance of proper endplate function and the relationships between endplate dysfunction, adjacent disc degeneration, and axial low back pain. Recent findings Changes to endplate morphology and composition that impair its permeability associate with disc degeneration. Endplate damage also associates with disc degeneration, and the progression of degeneration may be accelerated and the chronicity of symptoms heightened when damage coincides with evidence of adjacent bone marrow lesions. Summary The endplate plays a key role in the development of disc degeneration and low back pain. Clarification of the mechanisms governing endplate degeneration and developments in clinical imaging that enable precise evaluation of endplate function and dysfunction will distinguish the correlative vs. causative nature of endplate damage and motivate new treatments that target pathologic endplate function.
Collapse
|
4
|
Abstract
Mechanical loading of the intervertebral disc (IVD) initiates cell-mediated remodeling events that contribute to disc degeneration. Cells of the IVD, nucleus pulposus (NP) and anulus fibrosus (AF), will exhibit various responses to different mechanical stimuli which appear to be highly dependent on loading type, magnitude, duration, and anatomic zone of cell origin. Cells of the NP, the innermost region of the disc, exhibit an anabolic response to low-moderate magnitudes of static compression, osmotic pressure, or hydrostatic pressure, while higher magnitudes promote a catabolic response marked by increased protease expression and activity. Cells of the outer AF are responsive to physical forces in a manner that depends on frequency and magnitude, as are cells of the NP, though they experience different forces, deformations, pressure, and osmotic pressure in vivo. Much remains to be understood of the mechanotransduction pathways that regulate IVD cell responses to loading, including responses to specific stimuli and also differences among cell types. There is evidence that cytoskeletal remodeling and receptor-mediated signaling are important mechanotransduction events that can regulate downstream effects like gene expression and posttranslational biosynthesis, all of which may influence phenotype and bioactivity. These and other mechanotransduction events will be regulated by known and to-be-discovered cell-matrix and cell-cell interactions, and depend on composition of extracellular matrix ligands for cell interaction, matrix stiffness, and the phenotype of the cells themselves. Here, we present a review of the current knowledge of the role of mechanical stimuli and the impact upon the cellular response to loading and changes that occur with aging and degeneration of the IVD.
Collapse
Affiliation(s)
- Bailey V Fearing
- Department of Biomedical Engineering & Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
| | - Paula A Hernandez
- Department of Orthopaedic Surgery, University of Texas Southwestern, Dallas, Texas
| | - Lori A Setton
- Department of Biomedical Engineering & Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
| | - Nadeen O Chahine
- Department of Orthopedic Surgery & Biomedical Engineering, Columbia University, New York, New York
| |
Collapse
|
5
|
Hodson NW, Patel S, Richardson SM, Hoyland JA, Gilbert HTJ. Degenerate intervertebral disc-like pH induces a catabolic mechanoresponse in human nucleus pulposus cells. JOR Spine 2018; 1:e1004. [PMID: 31463436 PMCID: PMC6711490 DOI: 10.1002/jsp2.1004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/22/2018] [Accepted: 02/12/2018] [Indexed: 11/07/2022] Open
Abstract
Mechanical stimulation is known to influence intervertebral disc (IVD) cell behavior and function, but the effect on disc cells is routinely considered in isolation from other microenvironmental factors. Acidic pH has been shown to be a prominent and detrimental microenvironmental factor present in degenerate IVDs, but its influence on the human disc cell mechanoresponse has never been studied. We investigated the response of agarose-encapsulated human nucleus pulposus (NP) cells to 0.004 MPa, 1.0 Hz and 1 hour of compression (Flexcell FX4000 Compression System) under pH conditions representative of nondegenerate (pH 7.1) and degenerate (pH 6.5) IVDs. Cell viability, extracellular matrix production, and expression of anabolic/anti-catabolic and catabolic genes were assessed. We report that preculture of NP cells in agarose gels was required in order for cells to be mechanoresponsive, and this correlated with increased type VI collagen, α5β1 integrin, and fibronectin expression. Furthermore, the matrix homeostatic response observed at pH 7.1 (representative of nondegenerate IVDs; increased aggrecan [AGC], tissue inhibitor of metalloproteinases-1 [TIMP1], matrix metalloproteinase-3 [MMP3], a disintegrin and metalloproteinase with thrombospondin motif-5 [ADAMTS5] gene expression) was RGD-integrin dependent, whereas only MMP3 remained mechanoresponsive at pH 6.5, and this was independent of RGD-integrins. Our findings suggest differential mechanotransduction pathways operating for specific genes, with RGD-integrin dependent AGC expression, but not RGD-independent MMP3 expression, inhibited at pH representative of degenerate IVDs (pH 6.5), which could contribute to the catabolic phenotype observed during IVD degeneration. CLINICAL SIGNIFICANCE Characterizing the influence of the mechanical and chemical intervertebral disc microenvironment on disc cells, particularly in disc degeneration, could help develop future therapeutic strategies for the treatment of discogenic back pain.
Collapse
Affiliation(s)
- Nathan W. Hodson
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Sonal Patel
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Stephen M. Richardson
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Judith A. Hoyland
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- NIHR Manchester Musculoskeletal Biomedical Research Unit, Central Manchester NHS Foundation TrustManchester Academic Health Science CentreManchesterUK
| | - Hamish T. J. Gilbert
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- Wellcome Trust Centre for Cell‐Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| |
Collapse
|
6
|
Zvicer J, Obradovic B. Bioreactors with hydrostatic pressures imitating physiological environments in intervertebral discs. J Tissue Eng Regen Med 2017; 12:529-545. [PMID: 28763577 DOI: 10.1002/term.2533] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 06/27/2017] [Accepted: 07/27/2017] [Indexed: 12/28/2022]
Abstract
Intervertebral discs are normally exposed to a variety of loads and stresses but hydrostatic pressure (HP) could be the main biosignal for chondrogenic cell differentiation and maintenance of this tissue. Although there are simple approaches to intermittently expose cell cultures to HP in separate material testing devices, utilization of biomimetic bioreactors aiming to provide in vitro conditions mimicking those found in vivo, attracts special attention. However, design of such bioreactors is complex due to the requirement of high HP magnitudes (up to 3 MPa) applied in different regimes mimicking pressures arising in intervertebral disc during normal daily activities. Furthermore, efficient mass transfer has to be facilitated to cells within 3D scaffolds, and the engineering challenges include avoidance or removal of gas bubbles in the culture medium before pressurization as well as selection of appropriate, biocompatible construction materials and maintenance of sterility during cultivation. Here, we review approaches to induce HP in 2D and 3D cell cultures categorized into 5 groups: (I) discontinuous systems with direct pressurization of the cultivation medium by a piston, (II) discontinuous systems with indirect pressurization by a compression fluid, (III) continuous systems with direct pressurization of the cultivation medium, static culture, (IV) continuous systems with culture perfusion, and (V) systems applying HP in conjunction with other physical signals. Although the complexity is increasing as additional features are added to the systems, the need to understand HP effects on cells and tissues in a physiologically relevant, yet precisely controlled, environment together with current technological advancements are leading towards innovative bioreactor solutions.
Collapse
Affiliation(s)
- Jovana Zvicer
- Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
| | - Bojana Obradovic
- Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
| |
Collapse
|
7
|
Pang L, Li P, Zhang R, Xu Y, Song L, Zhou Q. Role of p38-MAPK pathway in the effects of high-magnitude compression on nucleus pulposus cell senescence in a disc perfusion culture. Biosci Rep 2017; 37:BSR20170718. [PMID: 28620118 PMCID: PMC5635211 DOI: 10.1042/bsr20170718] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/14/2017] [Accepted: 06/14/2017] [Indexed: 01/12/2023] Open
Abstract
Nucleus pulposus (NP) cell senescence is a typical pathological feature within the degenerative intervertebral disc. As a potential inducing and aggregating factor of disc degeneration, mechanical overloading affects disc biology in multiple ways. The present study was to investigate the NP cell senescence-associated phenotype under intermittent high compression in an ex vivo disc bioreactor culture, and the role of the p38-MAPK pathway in this regulatory process. Porcine discs were cultured in culture chambers of a self-developed mechanically active bioreactor and subjected to different magnitudes of dynamic compression (low-magnitude and high-magnitude: 0.1 and 1.3 MPa at a frequency of 1.0 Hz for 2 h per day respectively) for 7 days. Non-compressed discs were used as controls. The inhibitor SB203580 was used to study the role of the p38-MAPK pathway in this process. Results showed that intermittent high-magnitude compression clearly induced senescence-associated changes in NP cells, such as increasing β-galactosidase-positive NP cells, decreasing PCNA-positive NP cells, promoting the formation of senescence-associated heterochromatic foci (SAHF), up-regulating the expression of senescence markers (p16 and p53), and attenuating matrix production. However, inhibition of the p38-MAPK pathway partly attenuated the effects of intermittent high-magnitude (1.3 MPa) compression on those described NP cell senescence-associated parameters. In conclusion, intermittent high-magnitude compression can induce NP cell senescence-associated changes in an ex vivo disc bioreactor culture, and the p38-MAPK pathway is involved in this process.
Collapse
Affiliation(s)
- Lianglong Pang
- Department of Spine Surgery, Liaocheng People's Hospital, Liaocheng, Shandong, 25200, China
| | - Pei Li
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
- Department of Orthopedic Surgery, No.89 Hospital of PLA, Weifang, Shandong, 261026, China
| | - Ruijie Zhang
- Department of Respiratory Medicine, The Third Xiangya Hospital, Central South University, Changsha, Hunan 410013, China
| | - Yuan Xu
- Department of Orthopedic Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Lei Song
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Qiang Zhou
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| |
Collapse
|
8
|
Influence of different frequencies of axial cyclic loading on time-domain vibration response of the lumbar spine: A finite element study. Comput Biol Med 2017; 86:75-81. [PMID: 28511121 DOI: 10.1016/j.compbiomed.2017.05.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 05/07/2017] [Accepted: 05/07/2017] [Indexed: 12/20/2022]
Abstract
Very few studies have quantitatively analyzed influence of the loading frequency on time-domain vibration response of the whole lumbar spine in the presence of a physiologic compressive preload. In this study, a three-dimensional non-linear finite element model of ligamentous L1-S1 segment was developed to predict time-domain dynamic response of the whole lumbar spine to axial cyclic loading with different frequencies. A compressive follower preload of 400 N was applied to the model to simulate the physiologic compressive load. Modal analysis was initially performed to extract axial resonant frequency of the model under a 40 kg upper body mass and the 400 N preload. The result showed that the axial resonant frequency was 7.77 Hz. Subsequently, transient dynamic analyses were performed on the model under a sinusoidal axial load of ±40 N at frequencies of 3, 5, 7, 9, 11, 13 and 15 Hz with the 400 N preload and 40 kg mass. The computational results (strains and stresses in the spinal components) were collected and plotted as a function of time. These predicted results were found to be frequency-dependent and consistent with the notion in engineering dynamics texts that the closer the loading frequency approaches the resonant frequency, the larger the response is. For example, the results for 5 Hz load compared to 3 Hz load showed a 68.6-111.5% increase in peak-to-bottom variations of the predicted response parameters, and the results for 13 Hz load compared to 11 Hz load showed a 26.4-37.8% decrease in these variations.
Collapse
|
9
|
Streijger F, Lee JH, Manouchehri N, Melnyk AD, Chak J, Tigchelaar S, So K, Okon EB, Jiang S, Kinsler R, Barazanji K, Cripton PA, Kwon BK. Responses of the Acutely Injured Spinal Cord to Vibration that Simulates Transport in Helicopters or Mine-Resistant Ambush-Protected Vehicles. J Neurotrauma 2016; 33:2217-2226. [DOI: 10.1089/neu.2016.4456] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Femke Streijger
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Jae H.T. Lee
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Neda Manouchehri
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Angela D. Melnyk
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jason Chak
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Seth Tigchelaar
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Kitty So
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Elena B. Okon
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Shudong Jiang
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Rachel Kinsler
- Enroute Care and Airworthiness Division, United States Army Aeromedical Research Laboratory, Fort Rucker, Alabama
| | - Khalid Barazanji
- Enroute Care and Airworthiness Division, United States Army Aeromedical Research Laboratory, Fort Rucker, Alabama
| | - Peter A. Cripton
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian K. Kwon
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Combined Neurosurgical and Orthopaedics Spine Program (CNOSP), Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
10
|
Li P, Gan Y, Xu Y, Song L, Wang H, Zhang C, Wang L, Zhao C, Luo L, Zhou Q. Matrix homeostasis within the immature annulus fibrosus depends on the frequency of dynamic compression: a study based on the self-developed mechanically active bioreactor. Biomech Model Mechanobiol 2016; 16:385-394. [PMID: 27590020 DOI: 10.1007/s10237-016-0823-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 08/22/2016] [Indexed: 02/06/2023]
Abstract
Evidence suggests that mechanical load is related to structural destruction of disk annulus fibrosus (AF) either in adult disk degeneration or in child disk acute injury. Both biochemical and biomechanical properties are different between immature and mature disks. However, the effects of mechanical compression on immature AF are not fully clear. This study was to investigate the effects of a relatively wide range of dynamic compressive frequency on matrix homeostasis within the immature AF. Immature disks from pig (3-4 months) were randomly assigned into the control group (non-compression) and compression groups (0.1, 0.5, 1.0, 3.0 and 5.0 Hz). All disks were bioreactor-cultured for 7 days. AF matrix production was evaluated by histology, gene expression, glycosaminoglycan (GAG) content, hydroxyproline (HYP) content and immunohistochemistry. Generally, no obvious difference was found in HE staining between control group and compression groups. However, alcian blue staining indicated proteoglycan content in the 5.0-Hz group was decreased compared with the control group and other compression groups. Similarly, a catabolic remodeling gene expression profile with the down-regulated matrix genes (aggrecan, collagen I and collagen II) and tissue inhibitor of metalloproteinases (TIMP-1 and TIMP-3) and the up-regulated matrix catabolic enzymes (ADAMTS-4 and MMP-3) was found in the 5.0-Hz group. Further analysis indicated that GAG content, HYP content and aggrecan protein deposition were also decreased in the 5.0-Hz group. Hence, we concluded that matrix homeostasis within the immature AF was compressive frequency dependent, and the relatively higher frequency (5.0 Hz) is unfavorable for matrix production within the immature AF. These findings will contribute to further understanding of the relationship between mechanical compression and immature AF biosynthesis.
Collapse
Affiliation(s)
- Pei Li
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China
| | - Yibo Gan
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China
| | - Yuan Xu
- Department of Orthopedic Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400038, China
| | - Lei Song
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China
| | - Haoming Wang
- Department of Orthopedic Surgery, Chongqing Three Gorges Central Hospital, Chongqing, 404000, China
| | - Chengmin Zhang
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China
| | - Liyuan Wang
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China
| | - Chen Zhao
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China
| | - Lei Luo
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China
| | - Qiang Zhou
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
| |
Collapse
|
11
|
Li P, Gan Y, Wang H, Xu Y, Song L, Zhang C, Li S, Zhou Q. Biological Responses of the Immature Annulus Fibrosus to Dynamic Compression in a Disc Perfusion Culture. Cells Tissues Organs 2016; 202:296-306. [PMID: 27415834 DOI: 10.1159/000446363] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2016] [Indexed: 11/19/2022] Open
Abstract
Mechanical stimuli participate in disc development and remodelling. However, the effects of mechanical load on the immature annulus fibrosus (AF) are largely unclear. This study aimed to investigate how the immature AF responded to dynamic compressive magnitude and duration. Immature porcine discs were bioreactor-cultured for 7 days and then dynamically compressed at various magnitudes (0.1, 0.2, 0.4, 0.8 and 1.3 MPa at a frequency of 1.0 Hz for 2 h/day) and durations (1, 2, 4 and 8 h/day at a magnitude of 0.4 MPa and a frequency of 1.0 Hz). Non-compressed discs were used as controls. The immature AF tissue was analysed for histology, gene expression (aggrecan, collagen I, ADAMTS-4, MMP-3, TIMP-1 and TIMP-3), biochemical content of glycosaminoglycans (GAG) and hydroxyproline (HYP) and aggrecan immunohistochemical staining. In the lower-compressive-magnitude groups (0.1, 0.2 and 0.4 MPa), the immature AF showed an up-regulation in the expression of matrix genes, GAG and HYP content and aggrecan deposition. In the compression duration groups, the GAG and HYP content and aggrecan deposition declined to a minimum in the 8-hour group, in which a catabolic gene expression profile was found. In conclusion, this study indicated that the effects of dynamic compression on the immature AF are magnitude and duration dependent and that catabolic remodelling within the immature AF can be induced by high compressive magnitudes and long compressive durations.
Collapse
|
12
|
Optical Coherence Tomographic Elastography Reveals Mesoscale Shear Strain Inhomogeneities in the Annulus Fibrosus. Spine (Phila Pa 1976) 2016; 41:E770-E777. [PMID: 26849796 PMCID: PMC4925193 DOI: 10.1097/brs.0000000000001463] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Basic science study using in vitro tissue testing and imaging to characterize local strains in annulus fibrosus (AF) tissue. OBJECTIVE To characterize mesoscale strain inhomogeneities between lamellar and inter-/translamellar (ITL) matrix compartments during tissue shear loading. SUMMARY OF BACKGROUND DATA The intervertebral disc is characterized by significant heterogeneities in tissue structure and plays a critical role in load distribution and force transmission in the spine. In particular, the AF possesses a lamellar architecture interdigitated by a complex network of extracellular matrix components that form a distinct ITL compartment. Currently, there is not a firm understanding of how the lamellar and ITL matrix coordinately support tissue loading. METHODS AF tissue samples were prepared from frozen porcine lumbar spines and mounted onto custom fixtures of a materials testing system that incorporates optical coherence tomography (OCT) imaging to perform tissue elastography. Tissues were subjected to 20 and 40% nominal shear strain, and OCT images were captured and segmented to identify regions of interest corresponding to lamellar and ITL compartments. Images were analyzed using an optical flow algorithm to quantify local shear strains within each compartment. RESULTS Using histology and OCT, we first verified our ability to visualize and discriminate the ITL matrix from the lamellar matrix in porcine AF tissues. Local AF strains in the ITL compartment (22.0 ± 13.8, 31.1 ± 16.9 at 20% and 40% applied shear, respectively) were significantly higher than corresponding strains in the surrounding lamellar compartment (12.1 ± 5.6, 15.3 ± 5.2) for all tissue samples (P < 0.05). CONCLUSION Results from this study demonstrate that the lamellar and ITL compartments of the AF distribute strain unevenly during tissue loading. Specifically, shear strain is significantly higher in the ITL matrix, suggesting that these regions may be more susceptible to tissue damage and more mechanobiologically active. LEVEL OF EVIDENCE N/A.
Collapse
|
13
|
Li P, Gan Y, Xu Y, Li S, Song L, Li S, Li H, Zhou Q. Osmolarity affects matrix synthesis in the nucleus pulposus associated with the involvement of MAPK pathways: A study of ex vivo disc organ culture system. J Orthop Res 2016; 34:1092-100. [PMID: 26576043 DOI: 10.1002/jor.23106] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 11/16/2015] [Indexed: 02/04/2023]
Abstract
Matrix homeostasis within the nucleus pulposus (NP) is important for disc function. Unfortunately, the effects of osmolarity on NP matrix synthesis in a disc organ culture system and the underlying mechanisms are largely unknown. The present study was to investigate the effects of different osmolarity modes (constant and cyclic) and osmolarity levels (hypo-, iso-, and hyper-) on NP matrix synthesis using a disc organ culture system and determine whether ERK1/2 or p38MAPK pathway has a role in this process. Porcine discs were cultured for 7 days in various osmotic media, including constant hypo-, iso-, hyper-osmolarity (330, 430, and 550 mOsm/kg, respectively) and cyclic-osmolarity (430 mOsm/kg for 8 h, followed by 550 mOsm/kg for 16 h). The role of ERK1/2 and p38MAPK pathways were determined by their inhibitors U0126 and SB202190 respectively. The expression of SOX9 and downstream aggrecan and collagen II, biochemical content, and histology were used to assess NP matrix synthesis. The findings revealed that NP matrix synthesis was promoted in iso- and cyclic-osmolarity cultures compared to hypo- or hyper-osmolarity culture although the level of matrix synthesis in cyclic-osmolarity culture did not reach that in iso-osmolarity culture. Further analysis suggested that inhibition of the ERK1/2 or p38MAPK pathway in iso- and cyclic-osmolarity cultures reduced NP matrix production. Therefore, we concluded that the effects of osmolarity on NP matrix synthesis depend on osmolarity level (hypo-, iso-, or hyper-) and osmolarity mode (constant or cyclic), and the ERK1/2 and p38MAPK pathways may participate in this process. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1092-1100, 2016.
Collapse
Affiliation(s)
- Pei Li
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Yibo Gan
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Yuan Xu
- Department of Orthopedic Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Songtao Li
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Lei Song
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Sukai Li
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Huijuan Li
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Qiang Zhou
- Department of Orthopedic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| |
Collapse
|
14
|
Spyropoulou A, Karamesinis K, Basdra EK. Mechanotransduction pathways in bone pathobiology. Biochim Biophys Acta Mol Basis Dis 2015; 1852:1700-8. [PMID: 26004394 DOI: 10.1016/j.bbadis.2015.05.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 05/12/2015] [Accepted: 05/14/2015] [Indexed: 12/16/2022]
Abstract
The skeleton is subject to dynamic changes throughout life and bone remodeling is essential for maintenance of bone functionality. The cell populations which predominantly participate in bone and cartilage remodeling, namely osteocytes, osteoblasts, osteoclasts and chondrocytes sense and respond to external mechanical signals and via a series of molecular cascades control bone metabolism and turnover rate. The aforementioned process, known as mechanotransduction, is the underlying mechanism that controls bone homeostasis and function. A wide array of cross-talking signaling pathways has been found to play an important role in the preservation of bone and cartilage tissue health. Moreover, alterations in bone mechanotransduction pathways, due to genetic, hormonal and biomechanical factors, are considered responsible for the pathogenesis of bone and cartilage diseases. Extensive research has been conducted and demonstrated that aberrations in mechanotransduction pathways result in disease-like effects, however only few signaling pathways have actually been engaged in the development of bone disease. The aim of the present review is to present these signaling molecules and cascades that have been found to be mechano-responsive and implicated in bone disease development, as revealed by research in the last five years. In addition, the role of these molecules as prognostic or diagnostic disease markers and their potential as therapeutic targets are also discussed.
Collapse
Affiliation(s)
- Anastasia Spyropoulou
- Department of Biological Chemistry, Cellular and Molecular Biomechanics Unit, University of Athens Medical School, 11527 Athens, Greece
| | - Konstantinos Karamesinis
- Department of Biological Chemistry, Cellular and Molecular Biomechanics Unit, University of Athens Medical School, 11527 Athens, Greece
| | - Efthimia K Basdra
- Department of Biological Chemistry, Cellular and Molecular Biomechanics Unit, University of Athens Medical School, 11527 Athens, Greece.
| |
Collapse
|
15
|
Gonzales S, Wang C, Levene H, Cheung HS, Huang CYC. ATP promotes extracellular matrix biosynthesis of intervertebral disc cells. Cell Tissue Res 2014; 359:635-642. [PMID: 25407524 DOI: 10.1007/s00441-014-2042-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 10/16/2014] [Indexed: 01/07/2023]
Abstract
We have recently found a high accumulation of extracellular adenosine triphosphate (ATP) in the center of healthy porcine intervertebral discs (IVD). Since ATP is a powerful extracellular signaling molecule, extracellular ATP accumulation might regulate biological activities in the IVD. The objective of this study was therefore to investigate the effects of extracellular ATP on the extracellular matrix (ECM) biosynthesis of porcine IVD cells isolated from two distinct anatomical regions: the annulus fibrosus (AF) and nucleus pulposus (NP). ATP treatment significantly promotes ECM deposition and corresponding gene expression (aggrecan and type II collagen) by both cell types in three-dimensional agarose culture. A significant increase in ECM accumulation has been found in AF cells at a lower ATP treatment level (20 μM) compared with NP cells (100 μM), indicating that AF cells are more sensitive to extracellular ATP than NP cells. NP cells also exhibit higher ECM accumulation and intracellular ATP than AF cells under control and treatment conditions, suggesting that NP cells are intrinsically more metabolically active. Moreover, ATP treatment also augments the intracellular ATP level in NP and AF cells. Our findings suggest that extracellular ATP not only promotes ECM biosynthesis via a molecular pathway, but also increases energy supply to fuel that process.
Collapse
Affiliation(s)
- Silvia Gonzales
- Department of Biomedical Engineering, College of Engineering, University of Miami, P.O. Box 248294, Coral Gables, FL, 33124-0621, USA
| | - Chong Wang
- Department of Biomedical Engineering, College of Engineering, University of Miami, P.O. Box 248294, Coral Gables, FL, 33124-0621, USA
| | - Howard Levene
- Department of Neurological Surgery, University of Miami, Miami, FL, 33136, USA
| | - Herman S Cheung
- Department of Biomedical Engineering, College of Engineering, University of Miami, P.O. Box 248294, Coral Gables, FL, 33124-0621, USA
- Geriatric Research, Education and Clinical Center, Miami Veterans Affairs Medical Center, Miami, FL, 33125, USA
| | - Chun-Yuh Charles Huang
- Department of Biomedical Engineering, College of Engineering, University of Miami, P.O. Box 248294, Coral Gables, FL, 33124-0621, USA.
| |
Collapse
|
16
|
Gilbert HTJ, Nagra NS, Freemont AJ, Millward-Sadler SJ, Hoyland JA. Integrin - dependent mechanotransduction in mechanically stimulated human annulus fibrosus cells: evidence for an alternative mechanotransduction pathway operating with degeneration. PLoS One 2013; 8:e72994. [PMID: 24039840 PMCID: PMC3764176 DOI: 10.1371/journal.pone.0072994] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 07/23/2013] [Indexed: 12/11/2022] Open
Abstract
Intervertebral disc (IVD) cells derived from degenerate tissue respond aberrantly to mechanical stimuli, potentially due to altered mechanotransduction pathways. Elucidation of the altered, or alternative, mechanotransduction pathways operating with degeneration could yield novel targets for the treatment of IVD disease. Our aim here was to investigate the involvement of RGD-recognising integrins and associated signalling molecules in the response to cyclic tensile strain (CTS) of human annulus fibrosus (AF) cells derived from non-degenerate and degenerate IVDs. AF cells from non-degenerate and degenerate human IVDs were cyclically strained with and without function blocking RGD – peptides with 10% strain, 1.0 Hz for 20 minutes using a Flexercell® strain device. QRT-PCR and Western blotting were performed to analyse gene expression of type I collagen and ADAMTS -4, and phosphorylation of focal adhesion kinase (FAK), respectively. The response to 1.0 Hz CTS differed between the two groups of AF cells, with decreased ADAMTS -4 gene expression and decreased type I collagen gene expression post load in AF cells derived from non-degenerate and degenerate IVDs, respectively. Pre-treatment of non-degenerate AF cells with RGD peptides prevented the CTS-induced decrease in ADAMTS -4 gene expression, but caused an increase in expression at 24 hours, a response not observed in degenerate AF cells where RGD pre-treatment failed to inhibit the mechano-response. In addition, FAK phosphorylation increased in CTS stimulated AF cells derived from non-degenerate, but not degenerate IVDs, with RGD pre-treatment inhibiting the CTS – dependent increase in phosphorylated FAK. Our findings suggest that RGD -integrins are involved in the 1.0 Hz CTS – induced mechano-response observed in AF cells derived from non-degenerate, but not degenerate IVDs. This data supports our previous work, suggesting an alternative mechanotransduction pathway may be operating in degenerate AF cells.
Collapse
Affiliation(s)
- Hamish T. J. Gilbert
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Navraj S. Nagra
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Anthony J. Freemont
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Sarah J. Millward-Sadler
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Judith A. Hoyland
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
- * E-mail:
| |
Collapse
|
17
|
Pasqualini M, Lavet C, Elbadaoui M, Vanden-Bossche A, Laroche N, Gnyubkin V, Vico L. Skeletal site-specific effects of whole body vibration in mature rats: from deleterious to beneficial frequency-dependent effects. Bone 2013; 55:69-77. [PMID: 23545229 DOI: 10.1016/j.bone.2013.03.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 03/13/2013] [Accepted: 03/16/2013] [Indexed: 01/03/2023]
Abstract
Whole body vibration (WBV) is receiving increasing interest as an anti-osteoporotic prevention strategy. In this context, selective effects of different frequency and acceleration magnitude modalities on musculoskeletal responses need to be better defined. Our aim was to investigate the bone effects of different vibration frequencies at constant g level. Vertical WBV was delivered at 0.7 g (peak acceleration) and 8, 52 or 90 Hz sinusoidal vibration to mature male rats 10 min daily for 5 days/week for 4 weeks. Peak accelerations measured by skin or bone-mounted accelerometers at L2 vertebral and tibia crest levels revealed similar values between adjacent skin and bone sites. Local accelerations were greater at 8 Hz compared with 52 and 90 Hz and were greater in vertebra than tibia for all the frequencies tested. At 52 Hz, bone responses were mainly seen in L2 vertebral body and were characterized by trabecular reorganization and stimulated mineral apposition rate (MAR) without any bone volume alteration. At 90 Hz, axial and appendicular skeletons were affected as were the cortical and trabecular compartments. Cortical thickness increased in femur diaphysis (17%) along with decreased porosity; trabecular bone volume increased at distal femur metaphysis (23%) and even more at L2 vertebral body (32%), along with decreased SMI and increased trabecular connectivity. Trabecular thickness increased at the tibia proximal metaphysis. Bone cellular activities indicated a greater bone formation rate, which was more pronounced at vertebra (300%) than at long bone (33%). Active bone resorption surfaces were unaffected. At 8 Hz, however, hyperosteoidosis with reduced MAR along with increased resorption surfaces occurred in the tibia; hyperosteoidosis and trend towards decreased MAR was also seen in L2 vertebra. Trabecular bone mineral density was decreased at femur and tibia. Thus the most favorable regimen is 90 Hz, while deleterious effects were seen at 8 Hz. We concluded that the skeleton is frequency-scalable, thus highlighting the importance of WBV regimen conditions and suggesting that cautions are required for frequencies less than 10 Hz, at least in rats.
Collapse
Affiliation(s)
- Marion Pasqualini
- INSERM U1059/LBTO, Université Jean Monnet, Université de Lyon, Saint-Étienne, France
| | | | | | | | | | | | | |
Collapse
|
18
|
Neidlinger-Wilke C, Galbusera F, Pratsinis H, Mavrogonatou E, Mietsch A, Kletsas D, Wilke HJ. Mechanical loading of the intervertebral disc: from the macroscopic to the cellular level. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2013; 23 Suppl 3:S333-43. [DOI: 10.1007/s00586-013-2855-9] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 05/10/2013] [Accepted: 06/03/2013] [Indexed: 12/24/2022]
|
19
|
Liao J, Ke M, Xu T, Lin L. Electroacupuncture inhibits apoptosis in annulus fibrosis cells through suppression of the mitochondria-dependent pathway in a rat model of cervical intervertebral disc degradation. Genet Mol Biol 2012; 35:686-92. [PMID: 23055810 PMCID: PMC3459421 DOI: 10.1590/s1415-47572012005000046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 05/09/2012] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to investigate whether treatment with electroacupuncture (EA) inhibited mitochondria-dependent apoptosis in annulus fibrosis (AF) cells in a rat model of cervical intervertebral disc degradation induced by unbalanced dynamic and static forces. Forty Sprague-Dawley rats were used in this study, of which 30 underwent surgery to induce cervical intervertebral disc degradation, 10 rats received EA at acupoints Dazhui (DU 14) and Shousanli (LI 10). TUNEL staining was measured to assess apoptosis in AF cells, immunohistochemistry was used to examine Bcl-2 and Bax expression, colorimetric assays were used to determine caspase 9 and caspase 3 activities and RT-PCR and western blotting were used to assess the mRNA and protein expression of Crk and ERK2. Treatment with EA reduced the number of AF-positive cells in TUNEL staining, increased Bcl-2-positive cells and decreased Bax-positive cells in immunohistochemical staining, significantly inhibited the activation of caspases-9 and -3, and enhanced the mRNA and protein expression of Crk and ERK2. Our data show that EA inhibits AF cell apoptosis via the mitochondria-dependent pathway and up-regulates Crk and ERK2 expression. These results suggest that treatment with may be a good alternative therapy for preventing cervical spondylosis.
Collapse
Affiliation(s)
- Jun Liao
- Department of Acupuncture and Moxa and Tuina, Fujian University of Traditional Chinese Medicine, Fujian, P.R. China
| | | | | | | |
Collapse
|
20
|
Neidlinger-Wilke C, Mietsch A, Rinkler C, Wilke HJ, Ignatius A, Urban J. Interactions of environmental conditions and mechanical loads have influence on matrix turnover by nucleus pulposus cells. J Orthop Res 2012; 30:112-21. [PMID: 21674606 DOI: 10.1002/jor.21481] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 05/26/2011] [Indexed: 02/04/2023]
Abstract
Disc degeneration is associated with several changes in the physicochemical environment of intervertebral disc cells. Nucleus pulposus (NP) cells in the center of degenerated discs are exposed to decreased glucose supply, osmolarity, pH, and oxygen levels. To understand the complexity of these interactions on a cellular level, we designed standardized experiments in which we compared responses to these environmental factors under normal levels with those seen under two different degrees of disc degeneration. We hypothesized that these changes in environmental stimuli influence gene expression of matrix proteins and matrix degrading enzymes and alter their responses to cyclic hydrostatic pressure (HP). Our results suggest that a simulation of degenerative conditions influences the degradation of disc matrix through impairing matrix formation and accelerating matrix resorption via up- or down-regulation of the respective target genes. The greatest effects were seen for decreases in glucose concentration and pH. Low oxygen had little influence. HP had little direct effect but appeared to counteract matrix degradation by reducing or inverting some of the adverse effects of other stimuli. For ongoing in vitro studies, interactions between mechanical stimuli and factors in the physicochemical environment should not be ignored as these could markedly influence results.
Collapse
|
21
|
Fernando H, Czamanski J, Yuan TY, Gu W, Abdi S, Huang CY. Mechanical loading affects the energy metabolism of intervertebral disc cells. J Orthop Res 2011; 29:1634-41. [PMID: 21484859 PMCID: PMC3137745 DOI: 10.1002/jor.21430] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Accepted: 03/15/2011] [Indexed: 02/04/2023]
Abstract
Research has shown that mechanical loading affects matrix biosynthesis of intervertebral disc (IVD) cells; however, the pathway(s) to this effect is currently unknown. Cellular matrix biosynthesis is an energy demanding process. The objective of this study was to investigate the effects of static and dynamic compressive loading on energy metabolism of IVD cells. Porcine annulus fibrosus (AF) and nucleus pulposus (NP) cells seeded in 2% agarose were used in this experiment. Experimental groups included 15% static compression and 0.1 and 1 Hz dynamic compression at 15% strain magnitude for 4 h. ATP, lactate, glucose, and nitric oxide (NO) contents in culture media, and ATP content in cell-agarose construct were measured using biochemical assays. While the total ATP content of AF cells was promoted by static and dynamic loading, only 1 Hz dynamic loading increased total ATP content of NP cells. Increases in lactate production and glucose consumption of AF cells suggest that ATP production via glycolysis is promoted by dynamic compression. ATP release and NO production of AF and NP cells were significantly increased by dynamic loading. Thus, this study clearly illustrates that static and dynamic compressive loading affect IVD cell energy production while cellular responses to mechanical loading were both cell type and compression type dependent.
Collapse
Affiliation(s)
- H.N. Fernando
- Stem Cell and Mechanobiology Lab, Dept of Biomedical Engineering, University of Miami, Coral Gables, Florida 33146, USA
| | - J. Czamanski
- Stem Cell and Mechanobiology Lab, Dept of Biomedical Engineering, University of Miami, Coral Gables, Florida 33146, USA
| | - T.-Y. Yuan
- Stem Cell and Mechanobiology Lab, Dept of Biomedical Engineering, University of Miami, Coral Gables, Florida 33146, USA, Tissue Biomechanics Lab, Dept of Biomedical Engineering, University of Miami, Coral Gables, Florida 33146, USA
| | - W.Y. Gu
- Tissue Biomechanics Lab, Dept of Biomedical Engineering, University of Miami, Coral Gables, Florida 33146, USA
| | - S. Abdi
- Department of Anesthesiology, Critical Care and Pain Medicine, BIDMC, Harvard Medical School, Boston, MA
| | - C.-Y.C. Huang
- Stem Cell and Mechanobiology Lab, Dept of Biomedical Engineering, University of Miami, Coral Gables, Florida 33146, USA
| |
Collapse
|
22
|
Chan SCW, Ferguson SJ, Gantenbein-Ritter B. The effects of dynamic loading on the intervertebral disc. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2011; 20:1796-812. [PMID: 21541667 DOI: 10.1007/s00586-011-1827-1] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 03/21/2011] [Accepted: 04/20/2011] [Indexed: 01/08/2023]
Abstract
Loading is important to maintain the balance of matrix turnover in the intervertebral disc (IVD). Daily cyclic diurnal assists in the transport of large soluble factors across the IVD and its surrounding circulation and applies direct and indirect stimulus to disc cells. Acute mechanical injury and accumulated overloading, however, could induce disc degeneration. Recently, there is more information available on how cyclic loading, especially axial compression and hydrostatic pressure, affects IVD cell biology. This review summarises recent studies on the response of the IVD and stem cells to applied cyclic compression and hydrostatic pressure. These studies investigate the possible role of loading in the initiation and progression of disc degeneration as well as quantifying a physiological loading condition for the study of disc degeneration biological therapy. Subsequently, a possible physiological/beneficial loading range is proposed. This physiological/beneficial loading could provide insight into how to design loading regimes in specific system for the testing of various biological therapies such as cell therapy, chemical therapy or tissue engineering constructs to achieve a better final outcome. In addition, the parameter space of 'physiological' loading may also be an important factor for the differentiation of stem cells towards most ideally 'discogenic' cells for tissue engineering purpose.
Collapse
Affiliation(s)
- Samantha C W Chan
- ARTORG Center for Biomedical Engineering, Spine Research Center, Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstrasse 78, 3014 Bern, Switzerland
| | | | | |
Collapse
|
23
|
Difference in Energy Metabolism of Annulus Fibrosus and Nucleus Pulposus Cells of the Intervertebral Disc. Cell Mol Bioeng 2011; 4:302-310. [PMID: 21625336 DOI: 10.1007/s12195-011-0164-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Low back pain is associated with intervertebral disc degeneration. One of the main signs of degeneration is the inability to maintain extracellular matrix integrity. Extracellular matrix synthesis is closely related to production of adenosine triphosphate (i.e. energy) of the cells. The intervertebral disc is composed of two major anatomical regions: annulus fibrosus and nucleus pulposus, which are structurally and compositionally different, indicating that their cellular metabolisms may also be distinct. The objective of this study was to investigate energy metabolism of annulus fibrosus and nucleus pulposus cells with and without dynamic compression, and examine differences between the two cell types. Porcine annulus and nucleus tissues were harvested and enzymatically digested. Cells were isolated and embedded into agarose constructs. Dynamically loaded samples were subjected to a sinusoidal displacement at 2 Hz and 15% strain for 4 h. Energy metabolism of cells was analyzed by measuring adenosine triphosphate content and release, glucose consumption, and lactate/nitric oxide production. A comparison of those measurements between annulus and nucleus cells was conducted. Annulus and nucleus cells exhibited different metabolic pathways. Nucleus cells had higher adenosine triphosphate content with and without dynamic loading, while annulus cells had higher lactate production and glucose consumption. Compression increased adenosine triphosphate release from both cell types and increased energy production of annulus cells. Dynamic loading affected energy metabolism of intervertebral disc cells, with the effect being greater in annulus cells.
Collapse
|
24
|
Yang X, Wang D, Hao J, Gong M, Arlet V, Balian G, Shen FH, Li XJ. Enhancement of matrix production and cell proliferation in human annulus cells under bioreactor culture. Tissue Eng Part A 2011; 17:1595-603. [PMID: 21303231 DOI: 10.1089/ten.tea.2010.0449] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Tissue engineering is a promising approach for treatment of disc degeneration. Herein, we evaluated effects of rotating bioreactor culture on the extracellular matrix production and proliferation of human annulus fibrosus (AF) cells. AF cells were embedded into alginate beads, and then cultured up to 3 weeks in a rotating wall vessel bioreactor or a static vessel. By real-time reverse transcription-polymerase chain reaction, expression of aggrecan, collagen type I and type II, and collagen prolyl 4-hydroxylase II was remarkably elevated, whereas expression of matrix metalloproteinase 3 and a disintegrin and metalloproteinase with thrombospondin motifs 5 was significantly decreased under bioreactor. Biochemical analysis revealed that the levels of the whole cell-associated proteoglycan and collagen were approximately five- and twofolds in rotating bioreactor, respectively, compared to those in static culture. Moreover, AF cell proliferation was augmented in rotating bioreactor. DNA contents were threefolds higher in rotating bioreactor than that in static culture. Expression of the proliferating cell nuclear antigen was robustly enhanced in rotating bioreactor as early as 1 week. Our findings suggested that rotating bioreactor culture would be an effective technique for expansion of human annulus cells for tissue engineering driven treatment of disc degeneration.
Collapse
Affiliation(s)
- Xinlin Yang
- Orthopaedic Research Lab, University of Virginia, Charlottesville, Virginia 22908, USA
| | | | | | | | | | | | | | | |
Collapse
|
25
|
latridis JC, Godburn K, Wuertz K, Alini M, Roughley PJ. Region-dependent aggrecan degradation patterns in the rat intervertebral disc are affected by mechanical loading in vivo. Spine (Phila Pa 1976) 2011; 36:203-9. [PMID: 20714280 PMCID: PMC2988868 DOI: 10.1097/brs.0b013e3181cec247] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Immunoblotting study to evaluate aggrecan degradation patterns in rat intervertebral discs (IVDs) subjected to mechanical overload. OBJECTIVE To evaluate the effects of in vivo dynamic compression overloading on aggrecan degradation products associated with matrix metalloproteinase (MMP) and aggrecanase activity in different regions of the IVD. SUMMARY OF BACKGROUND DATA Aggrecan cleavage at the MMP and aggrecanase sites is an important event in human IVD aging, with distinct cleavage patterns in the anulus and nucleus regions.No such information is available on regional variations in rat IVDs, nor on how such cleavage is affected by mechanical loading. METHODS Sprague-Dawley rats were instrumented with an Ilizarov-type device and subjected to dynamic compression (1 MPa and 1 Hz for 8 hours per day for 8 weeks). Control, sham, and overloaded IVDs were separated by disc region and analyzed for aggrecan degradation products using immunoblotting techniques, with antibodies specific for the aggrecanase and MMP cleavage sites in the interglobular domain of aggrecan. RESULTS Control IVDs exhibited strong regional variation in aggrecan degradation patterns with minimal degradation products being present in the nucleus pulposus, degradation products associated with aggrecanase cleavage predominating in the inner anulus fibrosus (AF), and degradation products associated with MMP cleavage predominating in the outer AF. Dynamic compression overloading increased the amount of aggrecan degradation products associated with MMP cleavage not only in the AF but also in the nucleus pulposus. Degradation profiles of sham IVDs were similar to control. CONCLUSION Aggrecan G1 regions resulting from proteolysis were found to have a strong regionally specific pattern in the rat IVD, which was altered under excessive loading. The shift from aggrecanase to MMP-induced degradation products with dynamic compression overloading suggests that protein degradation and loss can precede major structural disruption in the IVD, and that MMP-induced aggrecan degradation may be a marker of mechanically induced disc degeneration.
Collapse
Affiliation(s)
- James C latridis
- School of Engineering, University of Vermont, Burlington, VT 05405, USA.
| | | | | | | | | |
Collapse
|
26
|
Gilbert HTJ, Hoyland JA, Freemont AJ, Millward-Sadler SJ. The involvement of interleukin-1 and interleukin-4 in the response of human annulus fibrosus cells to cyclic tensile strain: an altered mechanotransduction pathway with degeneration. Arthritis Res Ther 2011; 13:R8. [PMID: 21276216 PMCID: PMC3241352 DOI: 10.1186/ar3229] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 12/01/2010] [Accepted: 01/28/2011] [Indexed: 01/30/2023] Open
Abstract
Introduction Recent evidence suggests that intervertebral disc (IVD) cells derived from degenerative tissue are unable to respond to physiologically relevant mechanical stimuli in the 'normal' anabolic manner, but instead respond by increasing matrix catabolism. Understanding the nature of the biological processes which allow disc cells to sense and respond to mechanical stimuli (a process termed 'mechanotransduction') is important to ascertain whether these signalling pathways differ with disease. The aim here was to investigate the involvement of interleukin (IL)-1 and IL-4 in the response of annulus fibrosus (AF) cells derived from nondegenerative and degenerative tissue to cyclic tensile strain to determine whether cytokine involvement differed with IVD degeneration. Methods AF cells were isolated from nondegenerative and degenerative human IVDs, expanded in monolayers and cyclically strained in the presence or absence of the cytokine inhibitors IL-1 receptor antagonist (IL-1Ra) or IL-4 receptor antibody (IL-4RAb) with 10% strain at 1.0 Hz for 20 minutes using a Flexcell strain device. Total RNA was extracted from the cells at time points of baseline control and 1 or 24 hours poststimulation. Quantitative real-time polymerase chain reaction was used to analyse the gene expression of matrix proteins (aggrecan and type I collagen) and enzymes (matrix metalloproteinase 3 (MMP3) and a disintegrin and metalloproteinase with a thrombospondin type 1 motif 4 (ADAMTS4)). Results Expression of catabolic genes (MMP3 and ADAMTS4) decreased in AF cells derived from nondegenerative tissue in response to 1.0-Hz stimulation, and this decrease in gene expression was inhibited or increased following pretreatment of cells with IL-1Ra or IL-4RAb respectively. Treatment of AF cells derived from degenerative tissue with an identical stimulus (1.0-Hz) resulted in reduced anabolic gene expression (aggrecan and type I collagen), with IL-1Ra or IL-4RAb pretreatment having no effect. Conclusions Both IL-1 and IL-4 are involved in the response of AF cells derived from nondegenerative tissue to 1.0-Hz cyclic tensile strain. Interestingly, the altered response observed at 1.0-Hz in AF cells from degenerative tissue appears to be independent of either cytokine, suggesting an alternative mechanotransduction pathway in operation.
Collapse
Affiliation(s)
- Hamish T J Gilbert
- School of Biomedicine, Faculty of Medical and Human Sciences, University of Manchester, Manchester M139PL, UK
| | | | | | | |
Collapse
|
27
|
Smith LJ, Nerurkar NL, Choi KS, Harfe BD, Elliott DM. Degeneration and regeneration of the intervertebral disc: lessons from development. Dis Model Mech 2010; 4:31-41. [PMID: 21123625 PMCID: PMC3008962 DOI: 10.1242/dmm.006403] [Citation(s) in RCA: 250] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Degeneration of the intervertebral discs, a process characterized by a cascade of cellular, biochemical, structural and functional changes, is strongly implicated as a cause of low back pain. Current treatment strategies for disc degeneration typically address the symptoms of low back pain without treating the underlying cause or restoring mechanical function. A more in-depth understanding of disc degeneration, as well as opportunities for therapeutic intervention, can be obtained by considering aspects of intervertebral disc development. Development of the intervertebral disc involves the coalescence of several different cell types through highly orchestrated and complex molecular interactions. The resulting structures must function synergistically in an environment that is subjected to continuous mechanical perturbation throughout the life of an individual. Early postnatal changes, including altered cellularity, vascular regression and altered extracellular matrix composition, might set the disc on a slow course towards symptomatic degeneration. In this Perspective, we review the pathogenesis and treatment of intervertebral disc degeneration in the context of disc development. Within this scope, we examine how model systems have advanced our understanding of embryonic morphogenesis and associated molecular signaling pathways, in addition to the postnatal changes to the cellular, nutritional and mechanical microenvironment. We also discuss the current status of biological therapeutic strategies that promote disc regeneration and repair, and how lessons from development might provide clues for their refinement.
Collapse
Affiliation(s)
- Lachlan J Smith
- Department of Orthopaedic Surgery, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | |
Collapse
|
28
|
Gilbert HTJ, Hoyland JA, Millward-Sadler SJ. The response of human anulus fibrosus cells to cyclic tensile strain is frequency-dependent and altered with disc degeneration. ACTA ACUST UNITED AC 2010; 62:3385-94. [PMID: 20617521 DOI: 10.1002/art.27643] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Mechanical loads are important for homeostasis of the intervertebral disc (IVD) cell matrix, with physiologic and nonphysiologic loads leading to matrix anabolism and catabolism, respectively. Previous investigations into the effects of load on disc cells have predominantly used animal models, with the limited number of human studies focusing primarily on nucleus pulposus cells. The aim of this study was to examine the effect of cyclic tensile strain (CTS) on human anulus fibrosus (AF) cells to ascertain whether the response was frequency-dependent and to compare AF cells derived from nondegenerated and degenerated tissue samples. METHODS AF cells were isolated from nondegenerated and degenerated human IVDs, expanded in monolayer, and cyclically strained for 20 minutes, applying 10% strain at a frequency of 1.0 Hz or 0.33 Hz with the use of a Flexcell strain device. Total RNA was extracted from the cells at baseline (control) and at 1, 3, and 24 hours following application of CTS. Real-time quantitative polymerase chain reaction was used to analyze gene expression of matrix proteins (aggrecan, type I collagen, and type II collagen) and enzymes (matrix metalloproteinases [MMPs] 3, 9, 13, and ADAMTS-4). RESULTS The expression of catabolic genes (MMP-3 and ADAMTS-4) in AF cells derived from nondegenerated tissue decreased in response to 1.0 Hz of CTS, whereas changing the frequency to 0.33 Hz resulted in a shift toward matrix catabolism. Application of 1.0 Hz of CTS reduced anabolic gene expression (aggrecan and type I collagen) in AF cells derived from degenerated tissue, with 0.33 Hz of CTS resulting in increased catabolic gene expression. CONCLUSION The response of human AF cells to CTS is frequency-dependent and is altered by degeneration.
Collapse
|
29
|
The combined effects of limited nutrition and high-frequency loading on intervertebral discs with endplates. Spine (Phila Pa 1976) 2010; 35:1744-52. [PMID: 20395884 DOI: 10.1097/brs.0b013e3181c48019] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Whole ovine caudal intervertebral discs were cultured under simulated-physiologic or high-frequency loading and either sufficient or limited nutrition for 7 days. OBJECTIVE To study the effect of high-frequency loading under sufficient or limited glucose conditions and to investigate the additive effects of load and nutrition on cell survival, gene expression, and cell activity after 7 days of culture. SUMMARY OF BACKGROUND DATA Limited nutrition and certain mechanical stimuli are generally believed to be etiologic factors for disc degeneration. Although these effects and their interactions have been demonstrated in cell culture, no investigations have been reported in entire discs. METHODS Discs were maintained in a whole organ culture bioreactor system under simulated-physiologic (0.2 Hz) or high-frequency (10 Hz) loading, in media with either limited (2 g/L) or sufficient (4.5 g/L) glucose concentration. After 7 days, cell viability, relative gene expression, newly synthesized chondroitin sulfate content, glycosaminoglycan synthesis rate, and disc morphology were assessed after culture and compared with fresh tissue. RESULTS Culture under either limited glucose or high-frequency loading conditions led to a significant drop in cell viability. Combined treatment with limited glucose and high-frequency loading resulted in an additive increase in cell death in both the anulus fibrosus and nucleus pulposus and in an increase in MMP13 gene expression. CONCLUSION Supporting in vivo studies and cell culture experiments, high-frequency loading simulating vibration conditions shows detrimental effects on intervertebral disc cells in whole organ culture. The effect on cell viability was exacerbated by limited nutrition culture. However, neither frequency nor limited glucose affected cell metabolism, measured by glycosaminoglycan synthesis rate. Longer culture periods may be required to detect changes at the extracellular matrix level.
Collapse
|
30
|
Xie M, Yang S, Win HL, Xiong L, Huang J, Zhou J. Rabbit annulus fibrosus cell apoptosis induced by mechanical overload via a mitochondrial apoptotic pathway. ACTA ACUST UNITED AC 2010; 30:379-84. [DOI: 10.1007/s11596-010-0361-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Indexed: 12/25/2022]
|
31
|
Malekian M, Trieu D, Owoc JS, Park SS, Hunter CJ. Investigation of the intervertebral disc and fused joint dynamics through experimental modal analysis and the receptance coupling method. J Biomech Eng 2010; 132:041004. [PMID: 20387967 DOI: 10.1115/1.4001114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Identification of intervertebral disc (IVD) dynamics is important in understanding the spine mechanism and behavior. This paper experimentally identifies the dynamics of the bovine caudal IVD using experimental modal analysis and the inverse receptance coupling method. Experimental modal analysis was performed on free-free mounted bovine caudal vertebrae joined by an IVD and a fused IVD joint. Shear, rotational, and axial dynamics of the joints are identified by curve fitting of the frequency response functions, and identifying the damping ratio, stiffness, and modal frequency in each axis. The identified dynamics are compared with the IVD joints with and without fusion. Results provide important insight into IVD dynamics and fused IVD dynamics. This method can be extended to identify human IVD joint dynamics.
Collapse
Affiliation(s)
- M Malekian
- Department of Mechanical and Manufacturing Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
| | | | | | | | | |
Collapse
|
32
|
Grad S, Alini M, Eglin D, Sakai D, Mochida J, Mahor S, Collin E, Dash B, Pandit A. Cells and Biomaterials for Intervertebral Disc Regeneration. ACTA ACUST UNITED AC 2010. [DOI: 10.2200/s00250ed1v01y201006tis005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
33
|
Guo LX, Zhang M, Li JL, Zhang YM, Wang ZW, Teo EC. Influence Prediction of Tissue Injury on Frequency Variations of the Lumbar Spine under Vibration. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2009; 13:521-6. [DOI: 10.1089/omi.2009.0026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, People's Republic of China
| | - Ming Zhang
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, People's Republic of China
| | - Jin-Li Li
- Department of Journal of Northeastern University, Northeastern University, Shenyang, People's Republic of China
| | - Yi-Min Zhang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, People's Republic of China
| | - Zhao-Wen Wang
- School of Materials and Metallurgy, Northeastern University, Shenyang, People's Republic of China
| | - Ee-Chon Teo
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore
| |
Collapse
|
34
|
Le Maitre CL, Fotheringham AP, Freemont AJ, Hoyland JA. Development of an in vitro model to test the efficacy of novel therapies for IVD degeneration. J Tissue Eng Regen Med 2009; 3:461-9. [PMID: 19444863 DOI: 10.1002/term.180] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Low back pain (LBP) is a major cause of disability worldwide that has been linked to intervertebral disc (IVD) degeneration. An improved understanding of the pathogenesis of disc degeneration is now developing, which is leading to the development of a number of possible future therapies targeted at the underlying pathology and regeneration strategies. Although results thus far are promising, the investigation of such therapies in an environment that mimics the mechanical environment of the human disc in vivo is problematic. The development of an in vitro model system that can maintain metabolically active IVD tissue within a loading environment pertaining to that of the human spine is crucial for testing the efficacy of future cell-based and tissue-engineering therapies for IVD degeneration. Here, using our novel loading rig, capable of mimicking the loading environment experienced within the human spine, we have cultured nucleus pulposus tissue explants, applied a daily hydrostatic loading regime for up to 2 weeks and investigated proteoglycan retention, metabolic activity and cellular phenotype. IVD tissue cultured under a loading environment pertaining to the in vivo loading environment maintained metabolic cell activity, proteoglycan content and cellular phenotype. Indeed, all parameters were improved in IVD tissue cultured with load compared to unloaded controls. Such a model is invaluable for investigations assessing the feasibility and efficacy of future therapeutic approaches to inhibiting degeneration or stimulating regeneration of the IVD, where the in vivo loading environment may be crucial to their success or failure.
Collapse
Affiliation(s)
- Christine L Le Maitre
- Biomedical Research Centre, Biosciences, Sheffield Hallam University, City Campus, Owen Building, Howard Street, Sheffield S1 1WB, UK
| | | | | | | |
Collapse
|
35
|
Cellular mechanobiology of the intervertebral disc: new directions and approaches. J Biomech 2009; 43:137-45. [PMID: 19828150 DOI: 10.1016/j.jbiomech.2009.09.019] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2009] [Indexed: 01/08/2023]
Abstract
The more we learn about the intervertebral disc (IVD), the more we come to appreciate the intricacies involved in transmission of forces through the ECM to the cell, and in the biological determinants of its response to mechanical stress. This review highlights recent developments in our knowledge of IVD physiology and examines their impact on cellular mechanobiology. Discussion centers around the continually evolving cellular and microstructural anatomy of the nucleus pulposus (NP) and the annulus fibrosus (AF) in response to complex stresses generated in support of axial load and spinal motion. Particular attention has been given to cells from the immature NP and the interlamellar AF, and assessment of their potential mechanobiologic contributions to the health and function of the IVD. In addition, several innovative approaches that have been brought to bear on studying the interplay between disc cells and their micromechanical environment are discussed. Techniques for "engineering" cellular function and technologies for fabricating more structurally defined biomaterial scaffolds have recently been employed in disc research. Such tools can be used to elucidate the biological and physical mechanisms by which different IVD cell populations are regulated by mechanical stress, and contribute to advancement of preventative and therapeutic measures.
Collapse
|
36
|
Korecki CL, Kuo CK, Tuan RS, Iatridis JC. Intervertebral disc cell response to dynamic compression is age and frequency dependent. J Orthop Res 2009; 27:800-6. [PMID: 19058142 PMCID: PMC2757142 DOI: 10.1002/jor.20814] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The maintenance of the intervertebral disc extracellular matrix is regulated by mechanical loading, nutrition, and the accumulation of matrix proteins and cytokines that are affected by both aging and degeneration. Evidence suggests that cellular aging may lead to alterations in the quantity and quality of extracellular matrix produced. The aims of this study were to examine the role of loading and maturation (a subset of aging), and the interaction between these two factors in intervertebral disc cell gene expression and biosynthesis in a controlled 3D culture environment. Cells were isolated from young (4-6 months) and mature (18-24 months) bovine caudal annulus fibrosus and nucleus pulposus tissue. Isolated cells were seeded into alginate and dynamically compressed for 7 days at either 0.1, 1, or 3 Hz or maintained as a free-swelling control. After 7 days, DNA and sulfated glycosaminoglycan contents were analyzed along with real time, quantitative reverse transcription-polymerase chain reaction analysis for collagen types I and II, aggrecan, and matrix metalloproteinase-3 gene expression. Results suggest that maturation plays an important role in intervertebral disc homeostasis and influences the cell response to mechanical loading. While isolated intervertebral disc cells responded to mechanical compression in 3D culture, the effect of loading frequency was minimal. Altered cellular phenotype and biosynthesis rates appear to be an attribute of the cell maturation process, potentially independent of changes in cellular microenvironment associated with lost nutrition and disc degeneration. Mature cells may have a decreased capacity to create or retain extracellular matrix components in response to mechanical loading compared to young cells.
Collapse
Affiliation(s)
- Casey L. Korecki
- Spine Bioengineering Lab, College of Engineering and Mathematical Sciences, University of Vermont, Burlington, Vermont 05405
| | - Catherine K. Kuo
- Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892
| | - Rocky S. Tuan
- Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892
| | - James C. Iatridis
- Spine Bioengineering Lab, College of Engineering and Mathematical Sciences, University of Vermont, Burlington, Vermont 05405
| |
Collapse
|
37
|
Le Maitre CL, Frain J, Millward-Sadler J, Fotheringham AP, Freemont AJ, Hoyland JA. Altered integrin mechanotransduction in human nucleus pulposus cells derived from degenerated discs. ACTA ACUST UNITED AC 2009; 60:460-9. [DOI: 10.1002/art.24248] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
38
|
Elder BD, Athanasiou KA. Synergistic and additive effects of hydrostatic pressure and growth factors on tissue formation. PLoS One 2008; 3:e2341. [PMID: 18523560 PMCID: PMC2394656 DOI: 10.1371/journal.pone.0002341] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 04/28/2008] [Indexed: 11/18/2022] Open
Abstract
Background Hydrostatic pressure (HP) is a significant factor in the function of many tissues, including cartilage, knee meniscus, temporomandibular joint disc, intervertebral disc, bone, bladder, and vasculature. Though studies have been performed in assessing the role of HP in tissue biochemistry, to the best of our knowledge, no studies have demonstrated enhanced mechanical properties from HP application in any tissue. Methodology/Principal Findings The objective of this study was to determine the effects of hydrostatic pressure (HP), with and without growth factors, on the biomechanical and biochemical properties of engineered articular cartilage constructs, using a two-phased approach. In phase I, a 3×3 full-factorial design of HP magnitude (1, 5, 10 MPa) and frequency (0, 0.1, 1 Hz) was used, and the best two treatments were selected for use in phase II. Static HP at 5 MPa and 10 MPa resulted in significant 95% and 96% increases, respectively, in aggregate modulus (HA), with corresponding increases in GAG content. These regimens also resulted in significant 101% and 92% increases in Young's modulus (EY), with corresponding increases in collagen content. Phase II employed a 3×3 full-factorial design of HP (no HP, 5 MPa static, 10 MPa static) and growth factor application (no GF, BMP-2+IGF-I, TGF-β1). The combination of 10 MPa static HP and TGF-β1 treatment had an additive effect on both HA and EY, as well as a synergistic effect on collagen content. This group demonstrated a 164% increase in HA, a 231% increase in EY, an 85% increase in GAG/wet weight (WW), and a 173% increase in collagen/WW, relative to control. Conclusions/Significance To our knowledge, this is the first study to demonstrate increases in the biomechanical properties of tissue from pure HP application, using a cartilage model. Furthermore, it is the only study to demonstrate additive or synergistic effects between HP and growth factors on tissue functional properties. These findings are exciting as coupling HP stimulation with growth factor application has allowed for the formation of tissue engineered constructs with biomechanical and biochemical properties spanning native tissue values.
Collapse
Affiliation(s)
- Benjamin D. Elder
- Department of Bioengineering, Rice University, Houston, Texas, United States of America
| | - Kyriacos A. Athanasiou
- Department of Bioengineering, Rice University, Houston, Texas, United States of America
- * E-mail:
| |
Collapse
|
39
|
Abstract
STUDY DESIGN A bovine intervertebral disc organ culture model was used to study the effect of dynamic compression magnitude on mechanical behavior and measurement of biosynthesis rate, cell viability, and mRNA expression. OBJECTIVE The objective of this study was to examine the effect of loading magnitude on intervertebral disc mechanics and biology in an organ culture model. SUMMARY OF BACKGROUND DATA The in vivo and cell culture response of intervertebral disc cells to dynamic mechanical loading provides evidence the disc responds in a magnitude dependent manner. However, the ability to link mechanical behavior of the disc with biologic phenomena has been limited. A large animal organ culture system facilitates measurements of tissue mechanics and biologic response parameters on the same sample allowing a broader understanding of disc mechanobiology. METHODS Bovine caudal intervertebral discs were placed in organ culture for 6 days and assigned to a static control or 1 of 2 dynamic compression loading protocols (0.2-1 MPa or 0.2-2.5 MPa) at 1 Hz for 1 hour for 5 days. Disc structure was assessed with measurements of dynamic modulus, creep, height loss, water content, and proteoglycan loss to the culture medium. Cellular responses were assessed through changes in cell viability, metabolism, and qRT-PCR analyses. RESULTS Increasing magnitudes of compression increased disc modulus and creep; however, all mechanical parameters recovered each day. In the anulus, significant increases in gene expression for collagen I and a trend of increasing sulfate incorporation were observed. In the nucleus, increasing gene expression for collagen I and MMP3 was observed between magnitudes and between static controls and the lowest magnitude of loading. CONCLUSION Results support the hypothesis that biologic remodeling precedes damage to the intervertebral disc structure, that compression is a healthy loading condition for the disc, and further support the link between applied loading and biologic remodeling.
Collapse
|
40
|
Hydrostatic pressure differentially regulates outer and inner annulus fibrosus cell matrix production in 3D scaffolds. Ann Biomed Eng 2007; 36:204-13. [PMID: 18026839 DOI: 10.1007/s10439-007-9407-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Accepted: 11/08/2007] [Indexed: 01/07/2023]
Abstract
Mechanical stimulation may be used to enhance the development of engineered constructs for the replacement of load bearing tissues, such as the intervertebral disc. This study examined the effects of dynamic hydrostatic pressure (HP) on outer and inner annulus (OA, IA) fibrosus cells seeded on fibrous poly(glycolic acid)-poly(L-lactic acid) scaffolds. Constructs were pressurized (5 MPa, 0.5 Hz) for 4 h/day from day 3 to day 14 of culture and analyzed using ELISAs and immunohistochemistry (IHC) to assess extracellular matrix (ECM) production. Both cell types were viable, with OA cells exhibiting more infiltration into the scaffold, which was enhanced by HP. ELISA analyses revealed that HP had no effect on type I collagen production while a significant increase in type II collagen (COL II) was measured in pressurized OA constructs compared to day 14 unloaded controls. Both OA and IA dynamically loaded scaffolds exhibited more uniform COL II elaboration as shown by IHC analyses, which was most pronounced in OA-seeded scaffolds. Overall, HP resulted in enhanced ECM elaboration and organization by OA-seeded constructs, while IA-seeded scaffolds were less responsive. As such, hydrostatic pressurization may be beneficial in annulus fibrosus tissue engineering when applied in concert with an appropriate cell source and scaffold material.
Collapse
|