10 research outputs found
A structurally and functionally biomimetic biphasic scaffold for intervertebral disc tissue engineering.
Tissue engineering offers high hopes for the treatment of intervertebral disc (IVD) degeneration. Whereas scaffolds of the disc nucleus and annulus have been extensively studied, a truly biomimetic and mechanically functional biphasic scaffold using naturally occurring extracellular matrix is yet to be developed. Here, a biphasic scaffold was fabricated with collagen and glycosaminoglycans (GAGs), two of the most abundant extracellular matrix components in the IVD. Following fabrication, the scaffold was characterized and benchmarked against native disc. The biphasic scaffold was composed of a collagen-GAG co-precipitate making up the nucleus pulposus-like core, and this was encapsulated in multiple lamellae of photochemically crosslinked collagen membranes comprising the annulus fibrosus-like lamellae. On mechanical testing, the height of our engineered disc recovered by similar to 82-89% in an annulus-independent manner, when compared with the 99% recovery exhibited by native disc. The annulus-independent nature of disc height recovery suggests that the fluid replacement function of the engineered nucleus pulposus core might mimic this hitherto unique feature of native disc. Biphasic scaffolds comprised of 10 annulus fibrosus-like lamellae had the best overall mechanical performance among the various designs owing to their similarity to native disc in most aspects, including elastic compliance during creep and recovery, and viscous compliance during recovery. However, the dynamic mechanical performance (including dynamic stiffness and damping factor) of all the biphasic scaffolds was similar to that of the native discs. This study contributes to the rationalized design and development of a biomimetic and mechanically viable biphasic scaffold for IVD tissue engineering.published_or_final_versio
Roles of Cell-matrix Interactions and Cytoskeleton during Chondrogenesis of Mesenchymal Stem Cells in 3D Collagen-GAG Scaffold
Poster Presentatio
Acid-based electrospinning of type I collagen nanofibers for neural tissue engineering
Abstract no. PB3
Fabrication of multi-component spinal motion segment-like construct using mesenchymal stem cells and collagen
Concurrent Session 3Oral Presentatio
Engineering a Multicomponent Spinal Motion Segment-Like Construct from Mesenchymal Stem Cells
Conference theme: The Intervertebral Disc - from Degeneration to Therapeutic Motion PreservationThe abstract can be viewed at http://www.spineresearchforum.org/WFSR_2014_Thieme_AbstractBook_with_Cover.pdfOral PresentationIntroduction
The task of engineering the intervertebral disc is challenging
as the complex tissue needs to integrate with the host tissue
and performits function after the implantation. The vertebrae
connected to the endplates are essential to integrate with the
host vertebrae tissue which had been shown by Luk et al in
whole disc transplantation.1 Hence, engineering the complex
tissue needs to integrate the different components of the
vertebrae (VB), cartilaginous endplate (CEP), nucleus pulposus
(NP), and annulus fibrosus (AF); both biologically and mechanically.
In this study, the multiple component spinal
motion segments were fabricated by integrating these components.
The construct was then loaded in a bioreactor and
supplied with mechanical and biological stimulation. The
functional aspect of the fabricated endplate-like construct
was evaluated by a permeability test.
Materials and Methods
Rabbit mesenchymal stem cells (rMSCs) were encapsulated in
collagen and induced to differentiate toward osteogenic and
chondrogenic lineages before fabricating trilayered osteochondral
(OC) constructs as previously mentioned. To test
the nutritional function of the OC construct which acts as the
endplate, rabbit nucleus pulposus cells (rNPCs)-encapsulated
collagen microspheres were trapped in a sealed chamber
formed with the OC construct such that the nutrients have
to diffuse through the OC construct to reach the inside of the
chamber. Cell viability of the rNPCs was then evaluated. To
fabricate the multiple component construct, a rMSCs encapsulated
collagen-GAG precipitate was added in between two
OC construct and placed in between the shaft of the bioreactor.
Then a layer of rMSC encapsulated collagen was formed
around the construct to form the AF-like lamella. Torsional
loading was applied onto the construct to study its effect on cell alignment in the AF-like lamella. Finally, one to three
layers of AF-like lamellae were added to the spinal motion
segment construct and cultured in the bioreactor with complex
loading for 14 days. Histological, ultrastructural, and
mechanical evaluation was done on the construct.
Results
In the custom developed functionality test for nutrient transport,
the rNPCs in the chamber were viable at the end of the
culture showed that nutrientswere able to diffuse through the
OC construct. For the effect of torsional loading on cell
alignment in the AF-like lamella, alignment analysis showed
that the cells were aligned along a preferred axis under
torsional loading compared with control group without loading.
However, no collagen fibers alignment was found in this
study. The multiple component construct was fabricated with
each component similar to the spinal motion segment. The
different components of the construct were well integrated
throughout the culture and were shown by histology. Mean
torsional stiffness of the constructs significantly increased as
the number of rMSC encapsulated AF-like layer increased.
Conclusion
This study demonstrated the feasibility to engineer a spinal
motion segment-like tissue with collagen and MSC. The OC
constructs demonstrated its nutritional function and can be
used as a vertebra-endplate construct in this model. rMSC
encapsulated in collagen gel can be induced to re-orientate
and align in a certain direction by applying cyclic torsional
force on the tubular structure. This can be a tissue engineered
model to study the effects of various strategies in functional
remodeling and maturation of the intervertebral disc.
Disclosure of Interest
None declared
Reference
1. Luk KD, Ruan DK. Intervertebral disc transplantation: a
biological approach to motion preservation. Eur Spine J
2008;17(Suppl 4):504–51