Are axial intervertebral disc biomechanics determined by osmosis?

Pieter Paul A. Vergroesen, Kaj S. Emanuel, Mirte Peeters, Idsart Kingma, Theodoor H. Smit

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The intervertebral disc faces high compressive forces during daily activities. Axial compression induces creeping fluid loss and reduction in disc height. With degeneration, disc fluids and height are progressively lost, altering biomechanics. It is assumed that this reduction of fluids is caused by a decline of osmolality within the disc due to proteoglycan depletion. Here we investigate the isolated effect of a reduction in osmosis on the biomechanical properties of the intervertebral disc. Continuous diurnal loading was applied to healthy caprine intervertebral discs in a loaded disc culture system for a total of 6. days. We increased testing bath osmolality with two doses of polyethylene-glycol (PEG), thereby reducing the osmotic gradient between the disc and the surrounding fluid. This way we could study the isolated effect of reduced osmosis on axial creep, without damaging the disc. We evaluated: daily creep and recovery, recovery time-constants and compressive stiffness. Additionally, we investigated water content. There was a strong dose-dependent effect of PEG concentration on water content and axial creep behaviour: disc height, amplitude and rate of creep and recovery were all significantly reduced. Axial compressive stiffness of the disc was not affected. Reduction of water content and amplitude of creep and recovery showed similarity to degenerative disc biomechanics. However, the time-constants increased, indicating that the hydraulic permeability was reduced, in contrast to what happens with degeneration. This suggests that besides the osmotic gradient, the permeability of the tissues determines healthy intervertebral disc biomechanics.

Original languageEnglish
Pages (from-to)4-9
JournalJournal of Biomechanics
Volume70
DOIs
Publication statusPublished - 21 Mar 2018

Cite this

Vergroesen, P. P. A., Emanuel, K. S., Peeters, M., Kingma, I., & Smit, T. H. (2018). Are axial intervertebral disc biomechanics determined by osmosis? Journal of Biomechanics, 70, 4-9. https://doi.org/10.1016/j.jbiomech.2017.04.027
Vergroesen, Pieter Paul A. ; Emanuel, Kaj S. ; Peeters, Mirte ; Kingma, Idsart ; Smit, Theodoor H. / Are axial intervertebral disc biomechanics determined by osmosis?. In: Journal of Biomechanics. 2018 ; Vol. 70. pp. 4-9.
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abstract = "The intervertebral disc faces high compressive forces during daily activities. Axial compression induces creeping fluid loss and reduction in disc height. With degeneration, disc fluids and height are progressively lost, altering biomechanics. It is assumed that this reduction of fluids is caused by a decline of osmolality within the disc due to proteoglycan depletion. Here we investigate the isolated effect of a reduction in osmosis on the biomechanical properties of the intervertebral disc. Continuous diurnal loading was applied to healthy caprine intervertebral discs in a loaded disc culture system for a total of 6. days. We increased testing bath osmolality with two doses of polyethylene-glycol (PEG), thereby reducing the osmotic gradient between the disc and the surrounding fluid. This way we could study the isolated effect of reduced osmosis on axial creep, without damaging the disc. We evaluated: daily creep and recovery, recovery time-constants and compressive stiffness. Additionally, we investigated water content. There was a strong dose-dependent effect of PEG concentration on water content and axial creep behaviour: disc height, amplitude and rate of creep and recovery were all significantly reduced. Axial compressive stiffness of the disc was not affected. Reduction of water content and amplitude of creep and recovery showed similarity to degenerative disc biomechanics. However, the time-constants increased, indicating that the hydraulic permeability was reduced, in contrast to what happens with degeneration. This suggests that besides the osmotic gradient, the permeability of the tissues determines healthy intervertebral disc biomechanics.",
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Vergroesen, PPA, Emanuel, KS, Peeters, M, Kingma, I & Smit, TH 2018, 'Are axial intervertebral disc biomechanics determined by osmosis?' Journal of Biomechanics, vol. 70, pp. 4-9. https://doi.org/10.1016/j.jbiomech.2017.04.027

Are axial intervertebral disc biomechanics determined by osmosis? / Vergroesen, Pieter Paul A.; Emanuel, Kaj S.; Peeters, Mirte; Kingma, Idsart; Smit, Theodoor H.

In: Journal of Biomechanics, Vol. 70, 21.03.2018, p. 4-9.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - Are axial intervertebral disc biomechanics determined by osmosis?

AU - Vergroesen, Pieter Paul A.

AU - Emanuel, Kaj S.

AU - Peeters, Mirte

AU - Kingma, Idsart

AU - Smit, Theodoor H.

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N2 - The intervertebral disc faces high compressive forces during daily activities. Axial compression induces creeping fluid loss and reduction in disc height. With degeneration, disc fluids and height are progressively lost, altering biomechanics. It is assumed that this reduction of fluids is caused by a decline of osmolality within the disc due to proteoglycan depletion. Here we investigate the isolated effect of a reduction in osmosis on the biomechanical properties of the intervertebral disc. Continuous diurnal loading was applied to healthy caprine intervertebral discs in a loaded disc culture system for a total of 6. days. We increased testing bath osmolality with two doses of polyethylene-glycol (PEG), thereby reducing the osmotic gradient between the disc and the surrounding fluid. This way we could study the isolated effect of reduced osmosis on axial creep, without damaging the disc. We evaluated: daily creep and recovery, recovery time-constants and compressive stiffness. Additionally, we investigated water content. There was a strong dose-dependent effect of PEG concentration on water content and axial creep behaviour: disc height, amplitude and rate of creep and recovery were all significantly reduced. Axial compressive stiffness of the disc was not affected. Reduction of water content and amplitude of creep and recovery showed similarity to degenerative disc biomechanics. However, the time-constants increased, indicating that the hydraulic permeability was reduced, in contrast to what happens with degeneration. This suggests that besides the osmotic gradient, the permeability of the tissues determines healthy intervertebral disc biomechanics.

AB - The intervertebral disc faces high compressive forces during daily activities. Axial compression induces creeping fluid loss and reduction in disc height. With degeneration, disc fluids and height are progressively lost, altering biomechanics. It is assumed that this reduction of fluids is caused by a decline of osmolality within the disc due to proteoglycan depletion. Here we investigate the isolated effect of a reduction in osmosis on the biomechanical properties of the intervertebral disc. Continuous diurnal loading was applied to healthy caprine intervertebral discs in a loaded disc culture system for a total of 6. days. We increased testing bath osmolality with two doses of polyethylene-glycol (PEG), thereby reducing the osmotic gradient between the disc and the surrounding fluid. This way we could study the isolated effect of reduced osmosis on axial creep, without damaging the disc. We evaluated: daily creep and recovery, recovery time-constants and compressive stiffness. Additionally, we investigated water content. There was a strong dose-dependent effect of PEG concentration on water content and axial creep behaviour: disc height, amplitude and rate of creep and recovery were all significantly reduced. Axial compressive stiffness of the disc was not affected. Reduction of water content and amplitude of creep and recovery showed similarity to degenerative disc biomechanics. However, the time-constants increased, indicating that the hydraulic permeability was reduced, in contrast to what happens with degeneration. This suggests that besides the osmotic gradient, the permeability of the tissues determines healthy intervertebral disc biomechanics.

KW - Creep

KW - Intervertebral disc

KW - Osmolality

KW - Permeability

KW - Proteoglycans

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