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Dose-dependent response of tissue-engineered intervertebral discs to dynamic unconfined compressive loading
Katherine D Hudson1, Robert I Mozia, Lawrence J Bonassar
11 Department of Biomedical Engineering, Cornell University , Ithaca, New York.
Tissue Engineering. Part A
|October 4, 2014
Summary
Dynamic compression enhances tissue-engineered intervertebral discs (TE-IVDs). Mechanical loading significantly increased glycosaminoglycans and mechanical properties, indicating improved functionality for potential implantation.
Area of Science:
- Biomaterials Science
- Tissue Engineering
- Orthopedics
Background:
- Degenerative disc disease poses significant challenges for current surgical treatments.
- Tissue-engineered intervertebral discs (TE-IVDs) offer a promising alternative for disc regeneration.
- Developing functional TE-IVDs requires optimization of their biochemical and mechanical properties.
Purpose of the Study:
- To investigate the effects of dynamic unconfined compression on the biochemical and mechanical properties of composite TE-IVDs.
- To determine the optimal strain amplitude for TE-IVD maturation.
- To assess region-specific responses within the TE-IVDs to mechanical stimulation.
Main Methods:
- Composite TE-IVDs were fabricated with an alginate nucleus pulposus (NP) and a type I collagen annulus fibrosus (AF).
- TE-IVDs underwent dynamic unconfined compression at varying strain amplitudes (1-10%) for two weeks.
- Biochemical assays (GAGs, hydroxyproline) and mechanical testing (moduli) were performed post-loading.
Main Results:
- Mechanical loading significantly increased GAGs and hydroxyproline content in both AF and NP regions.
- A dose-dependent increase in both equilibrium (2-fold) and instantaneous (4.3-fold) moduli was observed.
- Optimal functional improvements were achieved at a 5% strain amplitude, with region-dependent responses.
Conclusions:
- Dynamic mechanical loading effectively enhances the functionality of composite TE-IVDs.
- The observed region-dependent responses suggest tailored maturation strategies are possible.
- This loading protocol shows potential for scaling to larger models to accelerate TE-IVD maturation for clinical application.
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