Page 86 - NNS 2014 Program & Abstract Book

patients based on their specific impairment may contribute to more
targeted treatment strategies.
A comprehensive analysis of gait-related data, including time-distance
and kinematic parameters as well as measures of lower-limb strength was
performed over a range of walking speeds in 22 iSCI patients and 21
healthy controls.
iSCI patients remained capable to modulate step length, cadence,
and gait-cycle timing (interlimb coordination) within their speed
range despite severe limitations in walking velocity (*50% reduc-
tion). However, hip-knee coordination (intralimb coordination) re-
mained distinctly altered and was inappropriately modulated at
increased walking speeds. This measure and its quantifiable charac-
teristics may reveal the severity of functional impairment and allow
for patient stratification. Principal component analysis (PCA) applied
on the multivariate set of gait data revealed that the largest variance
was determined by parameters of walking speed and movement dy-
namics (PC1 45%), while measures representing interlimb (20%) or
intralimb (12%) coordination came to lie along the PC2 and PC3 axes,
respectively.
In iSCI distinct clusters of interrelated gait parameters can be
discerned that may reflect distinct domains of neural control of
walking. Data-driven analysis of gait-related parameters may im-
prove the evaluation of therapeutic interventions and accelerate the
identification of targeted interventions to increase locomotor out-
come in iSCI.
Key words
gait pattern, locomotion, motor control, spinal cord injury
B2-07
HINDLIMB MUSCLE STRETCH REDUCES LOCOMOTOR
FUNCTION AFTER A SPINAL CORD INJURY: ACUTE AND
CHRONIC TIME POINTS
Keller, A.1, Shum-Siu, A.2, Wainwright, G.3, Seibt, E.3 , Magnuson, D.2
1University of Louisville, Department of Physiology and Biophysics,
Louisville, USA
2Neurological Surgery, Louisville, USA
3Speed School of Engineering, Louisville, USA
After spinal cord injury (SCI), patients commonly develop spasticity
and contractures as secondary complications of ‘‘upper motor neu-
ron’’ lesions. Physical therapists use stretching maneuvers to maintain
extensibility of soft tissues and to manage spasticity. However,
available evidence that supports stretching as an effective rehabilita-
tion technique is unconvincing. Previous studies in our lab found that
stretching has negative effects on locomotor recovery in rats with
acute mild thoracic SCIs. The present study utilized a more clinically
relevant moderately-severe contusion injury, to determine the effects
of stretching on locomotion at acute and chronic time points and to
observe how stretching influences in-cage activity. Female SD rats
with 25 g-cm T10 contusion injuries received our standard 24-minute
stretch protocol, daily for 5 weeks starting 4 days (acute) or, for 4
weeks starting 12 weeks (chronic) post-injury. Deficits in locomotion
were evident in the acute animals after only 5 days of stretching. As
animals regained muscle tone by week 3 post-injury, ‘therapists’ had
to apply more pressure during stretch in order to achieve a normal end
range of motion. A more intense stretch, which was maintained for the
following 2 weeks, resulted in even greater impairments in locomo-
tion. In the chronic group dramatic drops in locomotor function were
also observed after only 5 days, and most animals had BBB scores of
0–3 for weeks 2, 3 and 4 of stretching. Importantly, overnight activity
did not differ between acute and control groups at any time point.
However, the chronic group traveled significantly less distance during
the weeks of therapy, presumably due to their severe hindlimb defi-
cits. Locomotor function recovered to the control levels for both
stretch groups within 3 weeks once daily stretching ceased. Our
findings show that stretching has an acute and temporarily detrimental
effect on locomotor recovery for animals with moderately-severe
contusion SCI.
Key words
locomotion, stretching
B2-08
IMPROVING LOCOMOTION IN SPINAL CORD INJURED
RATS: A BIOENGINEERING APPROACH
Silva, N.A., Gomes, E.D., Leite-Almeida, H., Sousa, N., Salgado, A.J.
Life and Health Sciences Research Institute (ICVS), University of
Minho, Braga, Portugal
Spinal cord injury (SCI) represents a significant health world problem.
Multidisciplinary approaches such those presented by tissue engi-
neering (TE) concepts hold great promise for SCI treatment. There-
fore the objective of the present work focused on the development of a
TE approach based on biodegradable polymers, 3D printing tech-
niques, adipose stem cells and olfactory ensheathing cells, aimed at
inducing the regeneration within SCI sites. 3D rigid tubular structures
with different thickness layers as well as different pore geometry and
orientation were processed using 3D plotting, a rapid prototyping
technology. Additionally, click chemistry techniques were used to
immobilize the GRGDS peptide into the gellan gum hydrogel. Then,
both the tubular scaffolds and de hydrogel were combined in order to
obtain a hybrid structure. Biological evaluation of the structures was
firstly carried out by determining their cytotoxicity, followed by the
encapsulation of stem cells on the gel phase. Results of the cytotox-
icity assays revealed that the scaffolds were non cytotoxic. Moreover,
chemical modification on the gellan gum hydrogel had a profound
influence on cell growth and morphology. Afterwards, scaffolds were
implanted on a rat hemisection model of SCI. Locomotory evaluation
was performed using BBB, open field and rotarod tests. The in vivo
evaluation revealed a good integration and an absence of inflam-
matory response to the scaffolds implantation. Moreover animals
implanted with the biodegradable structures showed significant im-
provements on BBB motor scale and on the activity box. In addition,
the combinatorial treatment led to a reduction in astroglyosis and
inflammatory response. In conclusion, our TE approach holds great
promise for SCI repair. Future work will be focus on the use of our TE
treatment in a contusion SCI model.
Key words
adipose stem cells, biomaterials, olfactory ensheathing cells, spinal
cord injury regeneration, tissue engineering
B2-09
UMBILICAL CORD MATRIX CELL SECRETOME REDUCES
VASCULAR PERMEABILITY & LESION VOLUME AFTER
TRAUMATIC SPINAL CORD INJURY
Vawda, R.1, Mikhail, M.1, Badner, A.M.1,2, Jose, A.1, Fehlings, M.G.1–3
1Division of Genetics and Development, Toronto Western Research
Institute, Krembil Neuroscience Program, University Health Network,
Toronto, Canada
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