NNS 2015 Program & Abstract Book

linked to cognitive impairment. Insulin-like growth factor-1 (IGF1) is

a potent neurotrophic factor capable of mediating neuroprotective and

neuroreparative processes. We have shown that elevating brain levels

of IGF1 stimulates hippocampal neurogenesis, enhancing the recovery

of immature neuron numbers after severe TBI in mice. However, little

is known about the effectiveness of IGF1 to promote long-term sur-

vival of neurons born after injury. To this end, astrocyte-specific IGF1

conditionally overexpressing mice (IGF1-TG) and wild-type (WT)

mice received controlled cortical impact or sham injury and 50 mg/kg

BrdU (i.p.) twice daily for 7 days following TBI. At six weeks fol-

lowing injury, total numbers of proliferated cells (BrdU

) and the

subset expressing a mature neuronal marker (NeuN

/BrdU

) were

counted at the injury epicenter. IGF1 significantly increased NeuN

BrdU

cell density at 6 weeks post-injury (p

0.05, compared to WT

injured mice). These data suggest that IGF1 stimulates the formation

of new hippocampal neurons acutely after brain injury and that these

new neurons survive to maturity. Future studies will examine the

electrophysiological function of these newborn neurons.

Keywords: Neurogenesis, Survival, IGF1

D8-14

SYNERGISTIC EFFECTS OF

-HYDROXYBUTYRATE AND

ACETYL-L-CARNITINE ON MITOCHONDRIAL FUNCTION

AFTER SPINAL CORD INJURY

Samirkumar Patel

, Jenna VanRooyen

, Patrick Sullivan

Alexander Rabchevsky

University of Kentucky, Spinal Cord & Brain Injury Research Cen-

ter, Dept of Physiology, Lexington, USA

University of Kentucky, Spinal Cord & Brain Injury Research Cen-

ter, Dept of Anatomy & Neurobiology, Lexington, USA

Mitochondrial dysfunction and oxidative stress are key factors after

contusion spinal cord injury (SCI) that lead to cell death and ulti-

mately functional deficits and, therefore, serve as pivotal targets for

SCI therapeutics. The current study evaluated the effects of admin-

istering ketone bodies, namely

-hydroxybutyrate (BHB) on mito-

chondrial function and oxidative stress following SCI. Moreover, we

tested BHB treatment either alone or delivered in combination with

acetyl-l-carnitine (ALC), an alternative bio-fuel for mitochondria.

Injured Sprague-Dawley rats (250 kdyn at L1/L2 spinal level) were

divided into 3 treatment groups (n

6/group): 1) Vehicle-treated-in-

jured, 2) 1.66 mmol/kg BHB-treated injured and 3) 1.66 mmol/kg

BHB

300 mg/kg ALC-treated injured. Drugs were administered in-

traperitoneally at 1 hr post-injury followed by insertion of an osmotic

mini-pump (s.c.) to deliver Vehicle or BHB (1.66 mmols/kg/day) or

BHB

ALC (300 mg/kg/day) for 24 hrs. A Sham group received only

a T12 laminectomy. At 24 hr post-injury, spinal cord mitochondria

were isolated and assessed for oxygen consumption rate (OCR) using

Seahorse Bioscience XFe24 extracellular flux analyser, as well as for

content of endogenous antioxidant glutathione (GSH). Results showed

significantly (p

0.05) decreased OCR (

50%) in Vehicle-treated

injured group compared to Shams and that treatment with BHB alone

significantly (p

0.05) preserved mitochondrial OCR (

35% lower

than Sham) after 24 hrs. Furthermore, combined treatment with

BHB

ALC additively restored mitochondrial OCR (

10% lower

than Sham) compared to BHB alone. Notably, while SCI also resulted

in significant (p

0.05) depletion of GSH (

25%), continuous

treatment with BHB completely restored GSH to normal levels. On-

going experiments are assessing whether combined BHB

ALC ad-

ditively normalize oxidative stress parameters and activities of key

mitochondrial enzyme complexes at 24 hr post-injury. Planned ex-

periments will assess the effects of such combinatorial treatments on

tissue sparing and recovery of hindlimb function following SCI.

Keywords: mitochondrial respiration, functional recovery, gluta-

thione, oxidative stress

D8-15

RE-PURPOSING AN FDA-APPROVED DRUG AS AN ANTI-

OXIDANT TO SCAVENGE REACTIVE CARBONYLS FOL-

LOWING TBI-INDUCED LIPID PEROXIDATION

Johnny Cebak

, Indrapal Singh, Juan Wang, Edward Hall

University of Kentucky, Department of Anatomy and Neurobiology,

Lexington, USA

Lipid peroxidation is a key contributor to the pathology of traumatic

brain injury (TBI). Traditional antioxidant therapies are intended to

scavenge the free radicals responsible for either the initiation or prop-

agation of lipid peroxidation (LP). However, targeting free radicals after

TBI is difficult as they rapidly react with other cellular macromolecules.

Our laboratory utilizes a novel antioxidant approach that scavenges the

final stages of LP i.e., the formation of carbonyl-containing breakdown

products. By scavenging breakdown products such as the highly reac-

tive and neurotoxic aldehydes 4-hydroxynonenal (4-HNE) and acrolein,

we are able to prevent the covalent modification of cellular proteins.

Without intervention, carbonyl additions render cellular proteins non-

functional which initiates the loss of ionic homeostasis, mitochondrial

failure, and subsequent neuronal death. Phenelzine (PZ) is an FDA-

approved monoamine oxidase inhibitor traditionally used for the treat-

ment of depression. However, PZ also possesses a hydrazine functional

group capable of covalently binding carbonyls. We hypothesized that

PZ will protect mitochondrial function and reduce markers of oxidative

damage by scavenging reactive aldehydes. Indeed, in our

ex vivo

ex-

periments the exogenous application of 4-HNE or acrolein significantly

reduced respiratory function and increased markers of oxidative damage

(

0.05) in isolated non-injured rat cortical mitochondria, whereas PZ

pre-treatment significantly prevented mitochondrial dysfunction and

oxidative damage in a concentration-related manner (

0.05). We

attribute PZ’s neuroprotective effects to the hydrazine moiety based on

experiments demonstrating that a structurally similar MAO inhibitor,

pargyline, that lacks the hydrazine moiety was unable to protect mito-

chondria. Our

in vivo

experiments demonstrated that PZ treatment,

10mg/kg s.c. begun at 15 minutes and repeated q12 hrs, significantly

attenuated mitochondrial respiratory failure 72 hours post-injury fol-

lowing rat controlled cortical impact injury, while also significantly

reducing cortical lesion volume 2 weeks post-injury. We are presently

investigating the optimal PZ dosing regimen for improvement of cog-

nitive and motor behavioral recovery and the therapeutic window for

the neuroprotective effects of the drug to determine its feasibility for

translation into human TBI testing.

Keywords: Phenelzine, Mitochondria, Oxidative Damage, 4-HNE,

acrolein, TBI

D8-16

BIOMARKER PROFILES SUPPORT A NEUROPROTECTIVE

EFFECT OF LEVETIRACETAM IN TBI: FINDINGS FROM

OPERATION BRAIN TRAUMA THERAPY

Stefania Mondello

, Megan Browning

, Deborah A. Shear

, Helen M.

Bramlett

, C. Edward Dixon

, Kara Schmid

, W. Dalton Dietrich

Kevin K. Wang

, Ronald L. Hayes

, Frank C. Tortella

, Patrick M.

Kochanek

A-118