This document presents results from a study characterizing glucose concentration microenvironments in ex vivo organ culture models of bovine and human intervertebral discs (IVDs). Computational models showed that sealing off the cartilage endplate (CEP) led to cell death in the nucleus pulposus due to low glucose concentrations. An experimental defect model found decreased disc height after 1 week when the CEP was sealed, indicating degeneration. Future work will analyze pressure, viability, and experimentally determine glucose levels to validate injectable cell therapies, as current culture methods may not replicate true physiological conditions.

1. D is ta n c e a lo n g Y a x is (m m )
GlucoseConcentration(mM)
0 1 0 2 0 3 0 4 0
0
1
2
3
4
5
1 5
1 6
1 7
1 8
1 9
2 0
Y0 Y
(F)
Ex Vivo Bovine 20 mM
Human Degenerated
D is ta n c e a lo n g X a x is (m m )
GlucoseConcentration(mM)
0 1 0 2 0 3 0
0
1
2
3
4
5
1 5
1 6
1 7
1 8
1 9
2 0 H u m a n H e a lth y
H u m a n D e g e n e ra te d
E x V iv o B o vin e 5 m M
E x V iv o B o vin e 2 0 m M
Ex V iv o B o vin e S e a le d
o ff C E P
X
AF NP
CEP
X0
X
Day7Day0
RESULTS - GLUCOSE CONCENTRATION MAP
Ex Vivo Bovine 5 mM
X0
X
X0
X
Y0
Y
Y0
Y
Y0
Y
Ex Vivo Bovine 5 mM
0 mM
2 mM
3 mM
4 mM
5 mM
1 mM
17 mM
18 mM
19 mM
20 mM
16 mM
X0
X
Y0
Y
Human Healthy Human Healthy
Human Degenerated
Ex Vivo Bovine 20 mM
Ex Vivo Bovine Sealed Off CEP Ex Vivo Bovine Sealed Off CEP
15 mM
X0
X
Y0
Y
0 mM
2 mM
3 mM
4 mM
5 mM
1 mM
0 mM
2 mM
3 mM
4 mM
5 mM
1 mM
0 mM
2 mM
3 mM
4 mM
5 mM
1 mM
X0 X
HeightofIVD(mm)
D a y 0 D a y 7
0
1 0
2 0
3 0
Day 7 Control
RESULTS - ONE WEEK DEFECT MODEL STUDY
MATERIALS & METHODS
Day 7 Defect Chamber
IVD
Isolation
IVD cultured for 7 days in
defect chamber with CEP
sealed off
Stirring essential to ensure no gradients
Computational model to map glucose
concentrations using Comsol ®
INTRODUCTION
Degeneration of the intervertebral disc (IVD) is considered as
a primary cause to back pain, which affects up to 80% of
people at some stage during their life costing €240 billion in
Europe annually.
Healthy
IVD
Early Stage
Degeneration
Late Stage
Degeneration
Nucleus Pulposus (NP)
Annulus Fibrosus (AF)
Cartilage End Plate
(CEP)
Transportation of vital nutrients, such as glucose play a
significant role in maintaining disc health. Disc degeneration
results in a loss of function and reduction in overall disc height.
CURRENT TREATMENTS
[2]
Disc replacement
Injectable cell based
therapy
OBJECTIVES
Develop a static organ culture system to induce degeneration
in a bovine IVD and to characterise the glucose nutrient
microenvironment that exists in ex vivo organ culture models.
DISCUSSION & CONCLUSION
This work was supported by the MSc in Bioengineering programme at Trinity College Dublin, Ireland.
TRINITY CENTRE FOR BIOENGINEERING
Y
Z
X
Y
Z
Y
X
Y
Z
Cell Death
Begins at
0.5 mM [3]
Computational models show that by sealing of the CEP cell death should
occur within the NP. A defect was formed within NP and change in disc
height was observed after a 1 week experimental study in defect chamber.
Future experiments will analyse intradiscal pressure and cell viability, as
well as experimentally determining the glucose concentration.
Current culture techniques may not truly represent the physiological
conditions within the IVD and therefore need to be revised in order to
validate injectable cell based therapies.
[1] Galbusera, F. 2011. Computer Methods in Biomechanics and Biomedical Engineering, 14(8), pp. 729-39.
[2] http://www.privatepatientadvocate.com/images/ArtificialDisc300.jpg
[3] Horner, H. A. & Urban, J. P. 2001. Spine, 26(23), pp. 2543-2549.
ACKNOWLEDGMENTS & REFERENCES
[1]