4 / 162
of new or doublecortin-positive neurons in the hippocampus. Mor-
phological and mRNA evidence indicated a hyperactive profile of
microglia in the TBI-LPS mice. For example, increased microglia
(Iba-1
+
) in the CA3 of the hippocampus from TBI-LPS mice had an
increased perimeter, max length, and proportional area. In addition,
microglia from TBI-LPS mice had the highest levels of TNF and
CCL2. Taken together, these data support the hypothesis that a diffuse
TBI sensitizes the brain to secondary challenges that augment cog-
nitive decline and impairment after injury.
Keywords: Microglia, Priming, Neuroinflammation, mFPI
T1-06
GENETIC AND PHARMACOLOGICAL MODULATION OF
TRIGEMINAL PAIN MOLECULES IN A MODEL OF TRAU-
MATIC BRAIN INJURY
Brittany Daiutolo
, Ashley Tyburski, Shannon Clark, Melanie Elliott
Thomas Jefferson University, Neurosurgery, Philadelphia, USA
Headache is the most common symptom of post-concussion syn-
drome, a highly prevalent disorder following mild to moderate trau-
matic brain injury (TBI). Headache may persist months to years
beyond the expected period of healing from post-traumatic inflam-
mation. A hypothesis that persistent inflammatory processes initiate
and maintain the sensitization of trigeminal pain neurons promoting
the development of chronic headache has been under investigation by
our laboratory. Two key pain signaling molecules implicated in mi-
graine, nitric oxide (NO) and calcitonin gene-related peptide (CGRP),
may play a role in post-traumatic headache. Following TBI, release of
nitric oxide (NO) is largely derived from the inducible nitric oxide
synthase isoform (iNOS). CGRP is a well-studied nociceptive neu-
ropeptide in migraine pathophysiology. The goal was to study the
relationship of CGRP and iNOS in the trigeminal pain circuit in a
model of a mild-moderate TBI, controlled cortical impact (CCI).
Pharmacotherapies known to inhibit the actions of CGRP, a CGRP
antagonist (MK8825) and sumatriptan, were administered post-injury
and compared to saline controls. The effects of treatment on iNOS
mRNA and protein were determined, as well as the cellular source and
distribution of iNOS in the trigeminal ganglia and trigeminal nucleus
caudalis (TNC). The effects of CCI in iNOS knockouts (KO) were
compared to wild-type mice with CCI on CGRP levels in the TNC.
Sensory behaviors indicative of headache were also measured. Allo-
dynic thresholds were significantly increased in MK8825 and suma-
triptan mice compared to CCI injured controls, p
<
0.01. Photophobia
was attenuated in MK8825 treated mice compared to vehicle treated
mice, p
<
0.05. Treatments significantly reduced the level of iNOS
mRNA and immunoreactivity in the TNC and ganglia, p
<
0.01. iNOS
co-localized with neurons in the TNC and glial cells in the ganglia.
Sumatriptan significantly reduced CGRP levels in the TNC, p
<
0.01.
iNOS deletion significantly attenuated CGRP at 3 days post-injury,
p
<
0.05. Findings support synergistic interactions between CGRP and
iNOS following TBI and indicate a prolonged therapeutic window for
CGRP-targeted treatment.
Keywords: CGRP, Nitric oxide
T1-07
LEVEL-SPECIFIC OPTIMIZATION OF CELLULAR INTER-
VENTION IN SPINAL CORD INJURY - A NEW PARADIGM
James Hong
1
, Jian Wang
1
, Yang Liu
1
, Anna Badner
1
, Rachel Dragas
1
,
Ahad Siddiqui
1
, Stefania Forner
1
, Reaz Vawda
1
, Michael Fehlings
1,2
1
Toronto Western Research Institute, Genetics and Development,
Toronto, Canada
2
University of Toronto, Surgery, Toronto, Canada
Although half of all spinal cord injuries (SCIs) occur at the cervical
level (cSCI), thoracic SCI (tSCI) models are preferred due to re-
duced mortality. Recently, there has been a shift towards cSCI
models given their higher clinical relevance. Despite differences in
vascular supply, similar pathophysiological profiles between tSCI
and cSCI have been assumed. Consequently, current cell therapy
paradigms in cSCI are largely inefficacious. By elucidating the
differences in the temporal profiles of secondary injury following
cSCI and tSCI, modulations to the injury milieu followed by timed
cellular intervention can then occur. We posit that temporal sec-
ondary injury profiles in SCI are level-dependent due to differences
in vascular disruption and neuroinflammation post-SCI. Wistar rats
received either a 23 g C6 or a 35 g T6 spinal cord clip-compression
injury for 1-minute after laminectomy. At 3, 7, 14 days post-SCI,
animals were sacrificed. Lesional and peri-lesional spinal cord tissue
was processed for RNASeq and ELISA. An identical set of lesioned
animals underwent high resolution ultrasound imaging for functional
vascularity. Time-matched laminectomy rats were used as controls.
Hierarchical clustering of RNASeq and ELISA arrays revealed that
the majority of pro-inflammatory cytokine expression peaked at days
3 and 14 after cSCI, and at days 7 and 14 after tSCI. Most differ-
entially expressed proteins were identified at days 7 and 14 between
tSCI and cSCI, and enrichment analysis revealed these proteins to be
involved in leukocyte differentiation and migration. This data cor-
relates strongly with a significant improvement in functional vas-
cularity from days 3–7 with a sharp decrease from days 7–14 after
cSCI, while tSCI only decreased at day 7–14. For the first time,
differences in pathophysiological profiles have been shown between
tSCI and cSCI. Thus, level-specific paradigms for cellular inter-
vention will be crucial for the successful clinical translation of cell
therapy in SCI.
Keywords: injury niche, ultrasound and power doppler, high-
throughput profiling, cervical spinal cord injury, thoracic spinal cord
injury, neural precursor cells
T1-08
KETOGENIC DIET DECREASES OXIDATIVE STRESS AND
IMPROVES MITOCHONDRIAL RESPIRATORY COMPLEX
ACTIVITY
Tiffany Greco
, David Hovda, Mayumi Prins
UCLA, Neurosurgery, Los Angeles, USA
Cerebral metabolism of ketones after traumatic brain injury (TBI) im-
proves contusion volume and behavior in an age-dependent manner.
Neuroprotection is attributed to improved cellular energetics, although
other properties contribute to the beneficial effects. Oxidative stress is
responsible for mitochondrial dysfunction after TBI. Ketones are re-
ported to decrease oxidative stress, increase antioxidants and scavenge
free-radicals. It is hypothesized that ketogenic diet (KD) will decrease
post-TBI oxidative stress and improve mitochondria. Postnatal day 35
(PND35) male rats were given sham or controlled cortical impact (CCI)
injury and placed on standard (STD) or KD. Ipsilateral cortex homoge-
nates and mitochondria were assayed for markers of oxidative stress,
antioxidant expression and mitochondrial function. Oxidative stress was
significantly increased at 6 and 24 hrs post-injury and attenuated by KD
while also inducing protein expression of antioxidants. Complex I ac-
tivity was inhibited in both STD and KD groups at 6 hrs and normalized
by 24 hrs. KD significantly improved Complex II-III activity that was
A-4