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enhanced survival of NSC. We used a controlled cortical impact device
to perform a TBI on immune-competent rats. Human NSCs were
transplanted into the rats 2 days after injury using FasL releasing aga-
rose hydrogels. The ability of FasL releasing hydrogels to induce T-cell
apoptosis and enhance NSC survival was analyzed 2 and 4 weeks after
injury (n
=
5 per animal group at each time point). Human NSC injec-
tions using cell media or agarose hydrogels were used as controls. We
found a significant enhancement of CD8
+
T cells expressing the apo-
ptosis marker caspase 8 in the rats injected with FasL releasing hy-
drogels in comparison to the control groups at 2 weeks post-injury.
Furthermore, the rats injected with FasL releasing hydrogels showed an
increase in the survival of human NSC at 2 and 4 weeks post-injury.
These results suggest that the FasL releasing hydrogels were successful
creating an immune-privileged zone around the NSC transplantation
site. The development of cell carrier strategies to induce localized
immune-suppression represents a novel approach to enhancing the
survival and efficacy of stem cell transplantation without systemically
affecting the patients’ immune system.
Keywords: Immune-suppression, xenografts, neural stem cell,
Traumatic brain injury
C7-05
ANALYSIS OF IBA-1 AND INFLAMMATORY RESPONSE IN
YOUNG ADULT MICE AFTER MILD TRAUMATIC BRAIN
INJURY
Michael Pezzillo
1,2
, Jennifer Charlton
1
, Alana Conti
1,2
1
John D DIngell VA Medical Center/Wayne State University School of
Medicine, Dept of Neurosurgery, Detroit, USA
2
Wayne State University School of Medicine, Dept of Psychiatry,
Detroit, USA
Mild traumatic brain injury (mTBI) makes up 70–80% of all TBI
cases in the USA. While mTBI’s deficits are often subtle, many
patients experience long-term neurological, cognitive, and behav-
ioral problems following injury. This study highlights the imperative
need to reduce the consequences of mTBI by examining the in-
flammatory response and upregulation of the ionized calcium-bind-
ing adaptor molecule 1 (Iba-1) in activated microglia. A mouse
model of mTBI was used to measure Iba-1 levels in various brain
regions to determine the specific time point, location and severity of
inflammation.
Anesthetized male young adult mice were administered a mild,
midline impact over intact skull and sham surgery was used as a
control. Brains were harvested at 6, 24, 48, and 72-hours, and 7-day
time points post-injury (n
=
3 per time point) and tissues prepared for
immunohistochemistry using antibodies against Iba-1.
Qualitative analysis was completed through the examination of the
morphological state of the microglia identified by positive Iba-1
staining. Microglia were classified as ramified (spiny) as unactivated
or amoeboid (smooth) as activated microglia. The degree of inflam-
mation was categorized as
+
(mild),
++
(moderate), and
+ + +
(severe)
and the state of activated response was measured.
Analysis established the greatest activated response occurred be-
tween 24 and 48-hours in mTBI mice. At these time points the
impact site, arcuate nucleus, and optic tract demonstrated the highest
degrees of inflammation in mTBI mice when compared with sham
controls. Also at the same time point, the nucleus accumbens, corpus
callosum, caudate putamen, and cortex demonstrated a moderate
response when compared with sham controls. The initial point of
increase in microglia activation was noted at the 24-hour time point,
except the optic tract, which had a robust response at the 6-hour time
point. The data may suggest parameters for a therapeutic window,
where targeted reduction in inflammation may limit the effects of
mTBI.
Keywords: mTBI, Iba-1, inflammatory response, immunohisto-
chemistry
C7-06
PERIPHERAL IMMUNE RESPONSE AFTER PEDIATRIC
TRAUMATIC BRAIN INJURY IN RABBIT
Lindsey Rasmussen
, Zhi Zhang, Manda Saraswati, Sujatha Kannan,
Courtney Robertson
Johns Hopkins Hospital, Anesthesiology and Critical Care Medicine,
Baltimore, USA
Background:
Increased levels of inflammatory cytokines and bio-
markers from the cerebral spinal fluid and brain have been found
following traumatic brain injury (TBI) in humans and in animal
models. However, inflammatory changes outside the brain in the pe-
ripheral immune system after TBI are less well studied. More spe-
cifically, the peripheral inflammatory response in pediatric TBI
remains largely unknown.
Objective:
To define changes in pro and anti-inflammatory pro-
cesses in the peripheral immune system in the acute and sub-acute
time period following pediatric TBI.
Methods:
Rabbit kits (n
=
64) from the same litter were randomly
divided into naı¨ve (no intervention), sham (craniotomy alone), and
TBI (controlled cortical impact; 6 mm impactor tip; 5.5 m/s, 2 mm
depth) groups. Spleens and peripheral blood were collected at 6 hrs, 1
day, 3 days, and 7 days post-injury. The mRNA levels of TNF-alpha,
IL1-Beta, IL10, IL-4, IL-6, YM1 and TGF-beta in the spleens and
peripheral blood were analyzed by real-time PCR. Spleens also un-
derwent immunohistochemical analysis for presence and quantifica-
tion of inflammatory cells.
Results:
Results show a decrease in anti-inflammatory cytokines
present in the TBI spleens at 6 hr and 1 day with no significant change
in pro-inflammatory cytokines, compared with naı¨ve and sham
groups. YM1 was found to be significantly increased in spleens 7 days
post injury. Aside from YM1, no change in pro or anti-inflammatory
cytokines was noted in the spleens at 3 or 7 days post injury.
Conclusion:
The response of the pediatric peripheral immune
system to TBI is differentially regulated following insult. Anti-
inflammatory cytokines circulating peripherally appear to preferen-
tially attenuate in the acute period post TBI. Recognition of these
alterations in the peripheral immune system may direct peripherally
administered therapies and testing for TBI in the future.
Keywords: traumatic brain injury, spleen, cytokine, inflammation
C7-07
NEUROINFLAMMATION IN A RABBIT MODEL OF PEDIA-
TRIC TRAUMATIC BRAIN INJURY
Zhi Zhang
, Manda Saraswati, Raymond Koehler, Courtney
Robertson, Sujatha Kannan
Johns Hopkins School of Medicine, ACCM, Baltimore, USA
Neuroinflammation following TBI is a major player in the secondary
response post-injury contributing to widespread cell death and tissue loss.
Microglial distribution and function in the developing brain plays an
important role in the inflammatory response following TBI in the im-
mature brain. In this study, we evaluated the sequential inflammatory
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