Duration-dependent influence of dynamic torsion on the intervertebral disc: an intact disc organ culture study

Chan, Samantha; Walser, Jochen; Ferguson, Stephen J.; Gantenbein, Benjamin

doi:10.1007/s00586-015-4140-6

Cited by 18 publications

(16 citation statements)

References 40 publications

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“…Similar to numerous previous studies [36,37], we found a long-term load duration decreased the macromolecule (aggrecan and collagen II) expression and matrix biochemical content (GAG and HYP). Furthermore, the expression of specific markers in juvenile NP cells was also down-regulated in the long-term load duration group.…”

Section: Discussionsupporting

confidence: 92%

Long-term load duration induces N-cadherin down-regulation and loss of cell phenotype of nucleus pulposus cells in a disc bioreactor culture

Zhang

Wang

et al. 2017

Bioscience Reports

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Long-term exposure to a mechanical load causes degenerative changes in the disc nucleus pulposus (NP) tissue. A previous study demonstrated that N-cadherin (N-CDH)-mediated signalling can preserve the NP cell phenotype. However, N-CDH expression and the resulting phenotype alteration in NP cells under mechanical compression remain unclear. The present study investigated the effects of the compressive duration on N-CDH expression and on the phenotype of NP cells in an ex vivo disc organ culture. Porcine discs were organ cultured in a self-developed mechanically active bioreactor for 7 days. The discs were subjected to different dynamic compression durations (1 and 8 h at a magnitude of 0.4 MPa and frequency of 1.0 Hz) once per day. Discs that were not compressed were used as controls. The results showed that long-term compression duration (8 h) significantly down-regulated the expression of N-CDH and NP-specific molecule markers (Brachyury, Laminin, Glypican-3 and Keratin 19), attenuated Alcian Blue staining intensity, decreased glycosaminoglycan (GAG) and hydroxyproline (HYP) contents and decreased matrix macromolecule (aggrecan and collagen II) expression compared with the short-term compression duration (1 h). Taken together, these findings demonstrate that long-term load duration can induce N-CDH down-regulation, loss of normal cell phenotype and result in attenuation of NP-related matrix synthesis in NP cells.

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Section: Discussionsupporting

confidence: 92%

Long-term load duration induces N-cadherin down-regulation and loss of cell phenotype of nucleus pulposus cells in a disc bioreactor culture

Zhang

Wang

et al. 2017

Bioscience Reports

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“…Thus, the architecture of the AF may act to protect collagen fibers from failure and reduce shear stresses at the AF‐endplate interface, which is a common site for disc failure under large rotation angles . It should be noted that while the AF structure may protect the disc from catastrophic failure, high local shear stresses may still initiate tissue remodeling towards the degenerative cascade …”

Section: Discussionmentioning

confidence: 99%

Contribution of facet joints, axial compression, and composition to human lumbar disc torsion mechanics

Bezci

Eleswarapu

Klineberg

et al. 2018

Journal Orthopaedic Research

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Stresses applied to the spinal column are distributed between the intervertebral disc and facet joints. Structural and compositional changes alter stress distributions within the disc and between the disc and facet joints. These changes influence the mechanical properties of the disc joint, including its stiffness, range of motion, and energy absorption under quasi-static and dynamic loads. There have been few studies evaluating the role of facet joints in torsion. Furthermore, the relationship between biochemical composition and torsion mechanics is not well understood. Therefore, the first objective of this study was to investigate the role of facet joints in torsion mechanics of healthy and degenerated human lumbar discs under a wide range of compressive preloads. To achieve this, each disc was tested under four different compressive preloads (300-1200 N) with and without facet joints. The second objective was to develop a quantitative structure-function relationship between tissue composition and torsion mechanics. Facet joints have a significant contribution to disc torsional stiffness (∼60%) and viscoelasticity, regardless of the magnitude of axial compression. The findings from this study demonstrate that annulus fibrosus GAG content plays an important role in disc torsion mechanics. A decrease in GAG content with degeneration reduced torsion mechanics by more than an order of magnitude, while collagen content did not significantly influence disc torsion mechanics. The biochemical-mechanical and compression-torsion relationships reported in this study allow for better comparison between studies that use discs of varying levels of degeneration or testing protocols and provide important design criteria for biological repair strategies. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

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“…Our experiments were performed with excised discs constrained by porous metal platens, a common boundary condition in organ culture systems . This condition was chosen for the present study to allow freezing and cryosectioning of the discs with minimal handling after injection, which was presumed to affect dye distribution.…”

Section: Discussionmentioning

confidence: 99%

“…26 The fluorescent dye measurements ( Figure 3 Our experiments were performed with excised discs constrained by porous metal platens, a common boundary condition in organ culture systems. [27][28][29] This condition was chosen for the present study to allow freezing and cryosectioning of the discs with minimal handling after injection, which was presumed to affect dye distribution. Pilot studies found no differences in either peak pressure or rate of depressurization between excised discs and discs still attached to adjacent vertebrae.…”

Section: Discussionmentioning

confidence: 99%

Slow depressurization following intradiscal injection leads to injectate leakage in a large animal model

2019

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Needle injection has been indicated as the most practical method of delivering therapeutic agents to the intervertebral disc due to the disc's largely avascular nature. As the disc is characterized by both high stiffness and low permeability, injection requires substantial pressure, which may not relax on practical time scales. Additionally, needle puncture results in a localized disruption to the annulus fibrosus that can provide a leakage pathway for pressurized injectate. We hypothesized that intradiscal injection would result in slow relaxation of injectate pressure, followed by leakage upon needle retraction. This hypothesis was tested via controlled injection of fluorescently labeled saline into bovine caudal discs via a 21 gauge needle. Injections were performed with 10% of total disc volume injected at 3%/s followed by a 4‐minute dwell. An analytical poroelastic model was calibrated to the experimental data and used to estimate injectate delivery with time. Experimental results confirmed both pressurization (with a peak of 199 ± 45 kPa) and slow recovery (final pressure of 81 ± 23 kPa). Injectate leakage through the needle puncture was verified following needle retraction in all samples. Histological sections of the discs displayed a clear defect at each disc's injection site with strong fluorescent labeling indicating a leakage pathway. The modeling results suggest that less than one‐fourth of the injected volume was absorbed by the tissue in 4 minutes. Taken together these results suggest that needle injection is a feasible, albeit inefficient method for delivery of therapeutic agents into the intervertebral disc. Particular care should be taken to aspirate un‐absorbed injectate prior to needle retraction to prevent leakage and exposure of surrounding tissues.

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Duration-dependent influence of dynamic torsion on the intervertebral disc: an intact disc organ culture study

Cited by 18 publications

References 40 publications

Long-term load duration induces N-cadherin down-regulation and loss of cell phenotype of nucleus pulposus cells in a disc bioreactor culture

Long-term load duration induces N-cadherin down-regulation and loss of cell phenotype of nucleus pulposus cells in a disc bioreactor culture

Contribution of facet joints, axial compression, and composition to human lumbar disc torsion mechanics

Slow depressurization following intradiscal injection leads to injectate leakage in a large animal model

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