Hyaluronic acid-based scaffolds for repair strategies after spinal cord injury: A behavioral study 1...
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Transcript of Hyaluronic acid-based scaffolds for repair strategies after spinal cord injury: A behavioral study 1...
Hyaluronic acid-based scaffolds for repair strategies after spinal cord injury: A
behavioral study
1The University of Texas at Austin, Department of Biomedical Engineering
2The University of Texas at Austin, Department of Psychology
Zin Z. Khaing1, Sydney A. Geissler1, Sandra V. Aguilar1, Timothy Schallert2 and Christine E. Schmidt1
Hyaluronic Acid (HA)
Extracellular and cell surface-associated Highly viscous and hydrophilic Can modulate cell behavior
(development, inflammation axonal growth) Vital role in scar-free wound healing
Other ApplicationsDermal Filler (Restylane®), Adhesion Barrier (Seprafilm®)
Hyaluronic Acid Materials
Images from healon.com and synvisc.com
Vitreous substitute (Healon®) Viscosupplementation (Synvisc®)
In Our Group
After Acute Spinal Cord Injury
Cell death Axonal damage Local hemorrhage Inflammation and edema
Acute Phase
Sub-acute Phase
Expansion of injured area during secondary phaseActivation of microglia and macrophagesAstrocyte activationScar formation (involve fibroblasts, meningial cells, infiltrating progenitors and astrocytes)
production of glial scar including CSPGs
HA after SCIPrevious studies from our lab showed that the presence of high
MW HA hydrogel can
Limit macrophage and microglia infiltration after SCI
Limit astrocyte response in vivo and astrocyte proliferation in vitro
Can alter the amount of CSPG deposition
Support axonal outgrowth after SCI
HA hydrogels after SCISpinal Cord Injury Model: Cervical lateral hemisection at
C3/C4The most clinically relevant model (63% of human SCI are at the cervical level)Rodents mainly use their forelimbs, therefore, behavioral deficits and improvements can be assessed more readily in an accurate manner
Hydrogels Used: GMHA, LN/GMHA, LN/gelfoam, gelfoam, and laminectomy (n=6 in each group)
Analysis: (a) Behavioral(b) Histological
Behavioral Tests1. Forelimb Locomotor Score (FLS) General forelimb usage during locomotion will be scored. Non-linear scale from 0-17.
2. Cylinder Forelimb exploration will be assessed. The numbers of forelimb contacts (left, right, and both) with the cylinder walls
were counted and expressed as a percentage of total placements.
3. Forelimb placing Forelimb placing tests response to sensorimotor/proprioceptive detection of
edge of table with capacity vibrissae (whiskers)
4. Adhesive removal (Sensory bias) Small adhesive backed (sticky) labels are placed on the distal–radial aspect of
both forelimbs Contact and removal times are recorded Tests preference for responding sensory stimuli as well as motor coordination
Forelimb Function
Pre-op3 day
1 week
2 week
4 week
6 week
8 week
10 week
12 week
02468
1012141618
FLS
Sham SurgeryLesioned
FLS
Scor
e
Pre-op3 day
1 week
2 week
4 week
6 week
8 week
10 week
12 week
02468
1012141618
Title
Sham SurgeryLesioned Al-ternatorsLesioned Non-alternatorsFL
S Sc
ore
(1-1
7)
Pre-op
3 day 1 week
2 week
4 week
6 week
8 week
10 week
12 week
0
2
4
6
8
10
12
14
16
18
FLS raw scores, Lesioned Forelimb
Sham Surgery
SCI + gelfoam
SCI + HA Gel
SCI+ HA/LN Gel
SCI + LN soaked gelfoam
FLS
Scor
e (0
-17)
Behavioral Tests1. Forelimb Locomotor Score (FLS) General forelimb usage during locomotion will be scored. Non-linear scale from 0-17.
2. Cylinder Forelimb exploration will be assessed. The numbers of forelimb contacts (left, right, and both) with the cylinder walls
were counted and expressed as a percentage of total placements.
3. Forelimb placing Forelimb placing tests response to sensorimotor/proprioceptive detection of
edge of table with capacity vibrissae (whiskers)
4. Adhesive removal (Sensory bias) Small adhesive backed (sticky) labels are placed on the distal–radial aspect of
both forelimbs Contact and removal times are recorded Tests preference for responding sensory stimuli as well as motor coordination
Cylinder Height
• LN-soaked gelfoam implants showed the most improved behavior
Pre-o
p3-d
ay
1-week
2-week
3-week
4-week
5-week
6-week
7-week
8-week
9-week
10-week
11-week
0123456789
Cylinder Height, Right Paw
Sham SurgerySCI + gelfoamSCI + HA GelSCI + HA/LN GelSCI + LN soaked gelfoam
Hei
ght
of R
each
Paw Preference (Cylinder)
• Implanted animals showed some increase in affected limb usage at 12 week post surgery.
Percent Right Percent Left Percent Right Percent Left Percent Right Percent LeftPre-surgery At 2 weeks At 12 weeks
0
20
40
60
80
100
120
Sham SurgerySCI + gelfoamSCI + HA gelSCI + HA/LN gelSCI + LN/gelfoam
Perc
ent L
imb
Usag
e
Behavioral Tests1. Forelimb Locomotor Score (FLS) General forelimb usage during locomotion will be scored. Non-linear scale from 0-17.
2. Cylinder Forelimb exploration will be assessed. The numbers of forelimb contacts (left, right, and both) with the cylinder walls
were counted and expressed as a percentage of total placements.
3. Forelimb placing Forelimb placing tests response to sensorimotor/proprioceptive detection of
edge of table with capacity vibrissae (whiskers)
4. Adhesive removal (Sensory bias) Small adhesive backed (sticky) labels are placed on the distal–radial aspect of
both forelimbs Contact and removal times are recorded Tests preference for responding sensory stimuli as well as motor coordination
Chronic (Ipsi-lesion)
Chronic (Contra-lesion)
0
1
2
3
4
Vibrissae-induced Placing
Sham SurgeryLesioned AlternatorsLesioned Non-alternators
Scor
e (0
-4)
Acknowledgements
Dr. Christine Schmidt Sydney GeisslerEntire Schmidt lab
CollaboratorsDr. Timothy Schallert, UT-Austin Raymond Grill, UT-Houston Supported By
Texas Paralysis FoundationDavid Van Wagner Foundation
Gillson Longenbough Foundation
Thank You!