Page 134 - NNS 2014 Program & Abstract Book

D1-04
STEM CELL TRANSPLANTATION-MEDIATED ALTERA-
TION OF MICROGLIAL PHENOTYPES IN INJURED MOUSE
BRAINS
Gao, J.1, Grill, R.J.2, Dunn, T.J.1, Bedi, S.2, Robert, H.2, Hasen, W.1,
Cox Jr, C.S.2 , Wu, P.1
1University of Texas Medical Branch, Galveston, USA
2University of Texas Medical School, Houston, USA
Neural stem cell (NSC) transplantation promotes functional recovery
from brain trauma. However, the underlying mechanisms still remain
largely unclear, which may hinder the exploration for a full potential
of cell therapy. Given the theory that stem cell transplantation worked
solely by replacing neural cells has been challenged, more studies are
now focusing on the interaction between grafted and host cells.
Special attention has been given to the cross-talk between grafted cells
and host microglia or infiltrated macrophages. It is currently unknown
whether and how grafted NSCs modulate the phenotypic changes of
host microglia/macrophages following traumatic brain injury. To this
end, we transplanted primed human NSCs into mouse brains 24 hours
after controlled cortical impact, collected brain tissues 6 days after
implantation, and then performed Immunohistochemical and western
blot analyses. Human NSC transplantation not only reduced brain
lesion size and decreased APP accumulation, but also favored a
transition of microglia/macrophages from the inflammatory M1 type
to the anti-inflammatory M2. Furthermore, most grafted cells mi-
grated to the injury site where they mainly differentiated into neurons,
and were phagocytized by either M1 or M2 cells without immune
suppression. Thus, our data suggest that grafted NSCs alter the host
environment by turning microglia/macrophages in the injured brain
from a pro-inflammatory to an anti-inflammatory phenotype, which
may enhance neuroprotection after traumatic brain injury.
Key words
anti-inflamation, grafted and host cell interaction, human neural stem
cell, microglial/macrophage
D1-05
CHANGING THE OUTCOME OF TRAUMATIC BRAIN IN-
JURY IN MICE. NO GENES. NO DRUGS
Taylor, J.M., Gregory, E.J., Berman, N.E., Berman, N.E.
University of Kansas Medical Center, Kansas City, USA
The major goal of preclinical studies of traumatic brain injury is to
discover new therapeutic interventions, but nearly all of the clinical
trials based on those discoveries have failed. A new approach is to
combine therapies, but it is not clear which therapies should be chosen
or when they should be delivered. The goal of this study was to de-
termine how outcomes of CCI can be altered without genetic or drug
approaches, providing an experimental model of good and bad out-
comes following comparable injury in the same species. In earlier
studies, we showed that in aged (22–24 month old C57/BL6 mice)
behavioral outcomes are worse, inflammatory responses are increased,
and neuroprotective responses in the HIF-1 alpha pathway, including
expression of erythropoietin (EPO), are decreased when compared with
adult (4–5 months old) mice. In this study, we determined whether
exercise can improve outcomes. Adult (4–5 months) mice were housed
in running wheel cages (runners) for 6 weeks prior to CCI, and they ran
an average of 5 km/night. Control adult mice housed in standard cages
were videotaped, and they did not attempt to exercise (couch mice).
Following the running period, mice were subjected to CCI, and both
motor and cognitive deficits were tested. Runners showed significantly
reduced deficits in the gridwalk test and improved retention scores in
the radial arm water maze when compared with couch mice. Expression
of EPO mRNA in the injured cortex was also increased in runners when
compared with couch mice. Thus, aging worsens outcomes and exercise
improves outcomes after CCI in mice, and expression of EPO is pos-
itively correlated with improved outcomes. Future studies comparing
injury responses in aged mice and exercised adult mice can provide
information on which mechanisms are activated at specific times fol-
lowing injury. Thus, these changes in injury responses that occur
without either genetic manipulation or drug treatment could be used to
identify specific treatment targets and appropriate therapeutic windows
for combined therapies.
Key words
aging, controlled cortical impact, erythropoietin, exercise, mouse
D1-06
DEXAMETHASONE POTENTIATES RECOVERY OF THE
BLOOD-BRAIN BARRIER AFTER PRIMARY BLAST INJURY
IN VITRO
Hue, C.D.1, Cao, S.1, Bass, C.R.2, Meaney, D.F.3, Morrison III, B.1
1Columbia University, NY, USA
2Duke University, Durham, USA
3University of Pennsylvania, Philadelphia, USA
The blood-brain barrier (BBB) has emerged as a promising thera-
peutic target for the treatment of blast-induced traumatic brain injury
in light of recent studies reporting BBB breakdown after blast expo-
sure. We demonstrate that post-injury treatment with dexamethasone
(DEX) potentiates recovery of the BBB in vitro.
Mouse brain endothelial cells (bEnd.3) were cultured to represent an
in vitro BBB model. Cells were seeded on Transwell inserts and cul-
tured for 7 days to confluency. A shock tube with a 76mm-diameter,
50mm-length driver section, and 1240mm-long driven section was used
to generate blast with a 571 kPa peak overpressure, 1.06ms duration,
and 186 kPa*ms impulse. Cultures were placed in a receiver designed to
mimic the skull-brain complex and mitigate wave reflections. Sham
controls were processed identically to injured cultures but not exposed
to blast. Injured and sham cultures were treated with DEX (10 lM) or
vehicle 30min post-injury. TEER was measured with an Endohm-12
chamber connected to an EVOMX Voltohmmeter (WPI). Hydraulic
conductivity was measured using a custom device to quantify fluid flow.
Following blast exposure, DEX-treated cultures exhibited full re-
covery of TEER 1 day after injury compared with 3 days in untreated
cultures, demonstrating potentiated barrier restoration due to treat-
ment. BBB recovery in DEX-treated cultures was permanent up to 3
days following blast. TEER of DEX-treated injured cultures remained
significantly elevated compared with untreated injured cultures and
untreated shams for 3 days after blast, suggesting that treatment was
associated with overall strengthening of the BBB. The time-course for
potentiated TEER recovery was supported by significantly reduced
hydraulic conductivity in DEX-treated cultures compared with un-
treated injured cultures for 3 days after blast, confirming faster re-
covery of barrier integrity. These results suggest utility in DEX
treatment for potentiating functional recovery of the BBB to mitigate
the effects of blast injury.
Key words
bEnd.3, blood-brain barrier, dexamethasone treatment, primary blast
injury, recovery
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