Publications

Scholarly Journals--Published

  • Baerresen KM, Miller KJ, Hanson ER, Miller JS, Dye RV, Hartman RE, Vermeersch D, Small GW. Neuropsychological tests for predicting cognitive decline in older adults. Neurodegener Dis Manag. 2015 Jun;5(3):191-201. PubMed PMID: 26107318. (10/2015)
  • Ashwal S, Ghosh N, Turenius C, Dulcich M, Denham C, Tone B, Hartman R, Snyder E & Obenaus A (2014) The reparative effects of neural stem cells in neonatal hypoxic ischemic injury are not influenced by host gender. Pediatric Research, in press   (10/2014)
  • Karain B, Xu D, Bellone J, Hartman RE, Shi W (2014) Globus pallidal neurons: Functional classification and effects of dopamine depletion. Synapse, in press.   (10/2014)
  • Milner E, Holtzman J, Friess S, Hartman R, Brody D, Han B & Zipfel G (2014) Endovascular-perforation subarachnoid hemorrhage fails to cause Morris water maze deficits in the mouse. Journal of Cerebral Blood Flow and Metabolism, in press.   (10/2014)
  • Manaenko A, Lekic T, Barnhart M, Hartman R, Zhang JH (2014) Inhibition of transforming growth factor-β attenuates brain Injury and neurological deficits in a rat model of germinal matrix hemorrhage. Stroke, in press.   (10/2014)
  • Kamper J E, Pop V, Fukuda A M, Ajao D O, Hartman R E, & Badaut J. (2013). Juvenile traumatic brain injury evolves into a chronic brain disorder: Behavioral and histological changes over 6 months. Experimental Neurology, 250, 8-19. Traumatic brain injury (TBI) refers to physical trauma to the brain that can lead to motor and cognitive dysfunctions. TBI is particularly serious in infants and young children, often leading to long-term functional impairments. Although clinical research is useful for quantifying and observing the effects of these injuries, few studies have empirically assessed the long-term effects of juvenile TBI (jTBI) on behavior and histology. After a controlled cortical impact delivered to postnatal 17 day old rats, functional abilities were measured after 3, 5, and 6 months using open field (activity levels), zero maze (anxiety-like behaviors), rotarod (sensorimotor abilities, coordination, and balance), and water maze (spatial learning and memory, swim speed, turn bias). Sensorimotor function was impaired for up to 6 months in jTBI animals, which showed no improvement from repeated test exposure. Although spatial learning was not impaired, spatial memory deficits were observed in jTBI animals starting at 3 months after injury. Magnetic resonance imaging and histological data revealed that the effects of jTBI were evolving for up to 6 months post-injury, with reduced cortical thickness, decreased corpus callosum area and CA1 neuronal cell death in jTBI animals distant to the impact site. These findings suggest that this model of jTBI produces long-term impairments comparable to those reported clinically. Although some deficits were stable over time, the variable nature of other deficits (e.g., memory) as well as changing properties of the lesion itself, suggest that the effects of a single jTBI produce a chronic brain disorder with long-term complications. (C) 2013 Elsevier Inc. All rights reserved. (12/2013) (link)
  • Fukuda A M, Adami A, Pop V, Bellone J A, Coats J S, . . . Badaut J. (2013). Posttraumatic reduction of edema with aquaporin-4 RNA interference improves acute and chronic functional recovery. Journal of Cerebral Blood Flow and Metabolism, 33(10), 1621-1632. Traumatic brain injury (TBI) is common in young children and adolescents and is associated with long-term disability and mortality. The neuropathologic sequelae that result from juvenile TBI are a complex cascade of events that include edema formation and brain swelling. Brain aquaporin-4 (AQP4) has a key role in edema formation. Thus, development of novel treatments targeting AQP4 to reduce edema could lessen the neuropathologic sequelae. We hypothesized that inhibiting AQP4 expression by injection of small-interfering RNA (siRNA) targeting AQP4 (siAQP4) after juvenile TBI would decrease edema formation, neuroinflammation, neuronal cell death, and improve neurologic outcomes. The siAQP4 or a RNA-induced silencing complex (RISC)-free control siRNA (siGLO) was injected lateral to the trauma site after controlled cortical impact in postnatal day 17 rats. Magnetic resonance imaging, neurologic testing, and immunohistochemistry were performed to assess outcomes. Pups treated with siAQP4 showed acute (3 days after injury) improvements in motor function and in spatial memory at long term (60 days after injury) compared with siGLO-treated animals. These improvements were associated with decreased edema formation, increased microglial activation, decreased blood-brain barrier disruption, reduced astrogliosis and neuronal cell death. The effectiveness of our treatment paradigm was associated with a 30% decrease in AQP4 expression at the injection site. (10/2013) (link)
  • Lekic T, Rolland W, Manaenko A, Krafft P R, Suzuki H, . . . Hartman R E. (2013). Pontine hemorrhage RESPONSE. Journal of Neurosurgery, 118(5), 1152-1153. (05/2013)
  • Rolland W B, Lekic T, Krafft P R, Hasegawa Y, Altay O, . . . Zhang J H. (2013). Fingolimod reduces cerebral lymphocyte infiltration in experimental models of rodent intracerebral hemorrhage. Experimental Neurology, 241, 45-55. T-lymphocytes promote cerebral inflammation, thus aggravating neuronal injury after stroke. Fingolimod, a sphingosine 1-phosphate receptor analog, prevents the egress of lymphocytes from primary and secondary lymphoid organs. Based on these findings, we hypothesized fingolimod treatment would reduce the number of T-lymphocytes migrating into the brain, thereby ameliorating cerebral inflammation following experimental intracerebral hemorrhage (ICH). We investigated the effects of fingolimod in two well-established murine models of ICH, implementing intrastriatal infusions of either bacterial collagenase (cICH) or autologous blood (bICH). Furthermore, we tested the long term neurological improvements by Fingolimod in a collagenase-induced rat model of ICH. Fingolimod, in contrast to vehicle administration alone, improved neurological functions and reduced brain edema at 24 and 72 h following experimental ICH in CD-1 mice (n = 103; p < 0.05). Significantly fewer lymphocytes were found in blood and brain samples of treated animals when compared to the vehicle group (p < 0.05). Moreover, fingolimod treatment significantly reduced the expression of intercellular adhesion molecule-1 (ICAM-1), interferon-gamma (INF-gamma), and interleukin-17 (IL-17) in the mouse brain at 72 h post-cICH (p < 0.05 compared to vehicle). Long-term neurocognitive performance and histopathological analysis were evaluated in Sprague-Dawley rats between 8 and 10 weeks post-cICH (n = 28). Treated rats showed reduced spatial and motor learning deficits, along with significantly reduced brain atrophy and neuronal cell loss within the basal ganglia (p < 0.05 compared to vehicle). We conclude that fingolimod treatment ameliorated cerebral inflammation, at least to some extent by reducing the availability and subsequent brain infiltration of T-lymphocytes, which improved the short and long-term sequelae after experimental ICH in rodents. (c) 2012 Elsevier Inc. All rights reserved. (03/2013) (link)
  • Huang L, Coats J S, Mohd-Yusof A, Yin Y F, Assaad S, . . . Obenaus A. (2013). Tissue vulnerability is increased following repetitive mild traumatic brain injury in the rat. Brain Research, 1499, 109-120. Repetitive mild traumatic brain injury (rmTBI) is an important medical concern for active sports and military personnel. Multiple mild injuries may exacerbate tissue damage resulting in cumulative brain injury and poor functional recovery. In the present study, we investigated the time course of brain vulnerability to rmTBI in a rat model of mild cortical controlled impact. An initial mild injury was followed by a second injury unilaterally at an interval of 1, 3, or 7 days. RmTBI animals were compared to single mTBI and sham treated animals. Neuropathology was assessed using multi-modal magnetic resonance imaging (MRI), followed by ex vivo tissue immunohistochemistry. Neurological and behavioral outcomes were evaluated in a subset of animals receiving rmTBI 3 days apart and shams. RmTBI 1 or 3 days apart but not 7 days apart revealed significantly exacerbated MRI-definable lesion volumes compared to single mTBI and shams. Increases in cortical tissue damage, extravascular iron and glial activation assessed by histology/immunohistochemistry correlated with in vivo MRI findings where shorter intervals (1 or 3 days apart) resulted in greater tissue pathology. There were no neurological deficits associated with rmTBI 3 day animals. At 1 mo post-injury, animals with rmTBI 3 days apart showed reduced exploratory behaviors and subtle spatial learning memory impairments were observed. Collectively, our findings suggest that the mildly-impacted brain is more vulnerable to repetitive injury when delivered within 3 days following initial mTBI. (c) 2012 Elsevier B.V. All rights reserved. (03/2013) (link)
  • Pop V, Sorensen D W, Kamper J E, Ajao D O, Murphy M P, . . . Badaut J. (2013). Early brain injury alters the blood-brain barrier phenotype in parallel with beta-amyloid and cognitive changes in adulthood. Journal of Cerebral Blood Flow and Metabolism, 33(2), 205-214. Clinical studies suggest that traumatic brain injury (TBI) hastens cognitive decline and development of neuropathology resembling brain aging. Blood-brain barrier (BBB) disruption following TBI may contribute to the aging process by deregulating substance exchange between the brain and blood. We evaluated the effect of juvenile TBI (jTBI) on these processes by examining long-term alterations of BBB proteins, beta-amyloid (A beta) neuropathology, and cognitive changes. A controlled cortical impact was delivered to the parietal cortex of male rats at postnatal day 17, with behavioral studies and brain tissue evaluation at 60 days post-injury (dpi). Immunoglobulin G extravasation was unchanged, and jTBI animals had higher levels of tight-junction protein claudin 5 versus shams, suggesting the absence of BBB disruption. However, decreased P-glycoprotein (P-gp) on cortical blood vessels indicates modifications of BBB properties. In parallel, we observed higher levels of endogenous rodent A beta in several brain regions of the jTBI group versus shams. In addition at 60 dpi, jTBI animals displayed systematic search strategies rather than relying on spatial memory during the water maze. Together, these alterations to the BBB phenotype after jTB1 may contribute to the accumulation of toxic products, which in turn may induce cognitive differences and ultimately accelerate brain aging. Journal of Cerebral Blood Flow & Metabolism (2013) 33, 205-214; doi:10.1038/jcbfm.2012.154; published online 14 November 2012 (02/2013) (link)
  • Lekic T, Rolland W, Manaenko A, Krafft P R, Kamper J E, . . . Zhang J H. (2013). Evaluation of the hematoma consequences, neurobehavioral profiles, and histopathology in a rat model of pontine hemorrhage Laboratory investigation. Journal of Neurosurgery, 118(2), 465-477. Object. Primary pontine hemorrhage (PPH) represents approximately 7% of all intracerebral hemorrhages (ICHs) and is a clinical condition of which little is known. The aim of this study was to characterize the early brain injury, neurobehavioral outcome, and long-term histopathology in a novel preclinical rat model of PPH. Methods. The authors stereotactically infused collagenase (Type VII) into the ventral pontine tegmentum of the rats, in accordance with the most commonly affected clinical region. Measures of cerebrovascular permeability (brain water content, hemoglobin assay, Evans blue, collagen Type IV, ZO-1, and MMP-2 and.MMP-9) and neurological deficit were quantified at 24 hours postinfusion (Experiment 1). Functional outcome was measured over a 30-day period using a vertebrobasilar scale (the modified Voetsch score), open field, wire suspension, beam balance, and inclined-plane tests (Experiment 2). Neurocognitive ability was determined at Week 3 using the rotarod (motor learning), T-maze (working memory), and water maze (spatial learning and memory) (Experiment 3), followed by histopathological analysis 1 week later (Experiment 4). Results. Stereotactic collagenase infusion caused dose-dependent elevations in hematoma volume, brain edema, neurological deficit, and blood-brain barrier rupture, while physiological variables remained stable. Functional outcomes mostly normalized by Week 3, whereas neurocognitive deficits paralleled the cystic cavitary lesion at 30 days. Obstructive hydrocephalus did not develop despite a clinically relevant 30-day mortality rate (approximately 54%). Conclusions. These results suggest that the model can mimic several translational aspects of pontine hemorrhage in humans and can be used in the evaluation of potential preclinical therapeutic interventions. (http://thejns.org/doi/abs/10.3171/20.10.JNS111836) (02/2013) (link)
  • Bellone J A, Vlkolinsky R, & Hartman R E. (2013). Low doses of iron or silicon radiation affect spatial memory in APP/PSEN1 double transgenic mice. Society for Neuroscience Abstract Viewer and Itinerary Planner, 43, . (2013)
  • Ropacki S A, Patel S M, & Hartman R E. (2013). Pomegranate Supplementation Protects against Memory Dysfunction after Heart Surgery: A Pilot Study. Evidence-Based Complementary and Alternative Medicine, , 8. Memory dysfunction is a common complaint following heart surgery and may be related to a diffuse ischemic state induced by microemboli dislodged during the procedure. Ischemia can induce damage by a number of mechanisms, including oxidative stress. Because pomegranates contain a variety of polyphenols with antioxidant and other potentially beneficial effects, we tested whether supplementation with a pomegranate extract before and after heart surgery could protect against postoperative cognitive dysfunction. Patients undergoing elective coronary artery bypass graft and/or valve surgery were given either 2 g of pomegranate extract (in 2 POMx pills) or placebo (pills containing no pomegranate ingredients) per day from one week before surgery to 6 weeks after surgery. The patients were also administered a battery of neuropsychological tests to assess memory function at 1 week before surgery (baseline), 2 weeks after surgery, and 6 weeks after surgery. The placebo group had significant deficits in postsurgery memory retention, and the pomegranate treatment not only protected against this effect, but also actually improved memory retention performance for up to 6 weeks after surgery as compared to presurgery baseline performance. (2013) (link)
  • Dulcich M S, & Hartman R E. (2013). Pomegranate Supplementation Improves Affective and Motor Behavior in Mice after Radiation Exposure. Evidence-Based Complementary and Alternative Medicine, , 8. Currently, NASA has plans for extended space travel, and previous research indicates that space radiation can have negative effects on cognitive skills as well as physical and mental health. With long-termspace travel, astronauts will be exposed to greater radiation levels. Research shows that an antioxidant-enriched diet may offer some protection against the cellular effects of radiation and may provide significant neuroprotection from the effects of radiation-induced cognitive and behavioral skill deficits. Ninety-six C57BL/6 mice (48 pomegranate fed and 48 control) were irradiated with proton radiation (2Gy), and two-month postradiation behaviors were assessed using a battery of behavioral tests to measure cognitive and motor functions. Proton irradiation was associated with depression-like behaviors in the tail suspension test, but this effect was ameliorated by the pomegranate diet. Males, in general, displayed worse coordination and balance than females on the rotarod task, and the pomegranate diet ameliorated this effect. Overall, it appears that proton irradiation, which may be encountered in space, may induce a different pattern of behavioral deficits in males than females and that a pomegranate diet may confer protection against some of those effects. (2013) (link)
  • Zhang J H, Badaut J, Tang J P, Obenaus A, Hartman R, & Pearce W J. (2012). The vascular neural network-a new paradigm in stroke pathophysiology. Nature Reviews Neurology, 8(12), 711-716. The concept of the neurovascular unit as the key brain component affected by stroke is controversial, because current definitions of this entity neglect mechanisms that control perfusion and reperfusion of arteries and arterioles upstream of the cerebral microcirculation. Indeed, although definitions vary, many researchers consider the neurovascular unit to be restricted to endothelial cells, neurons and glia within millimetres of the cerebral capillary microcirculation. This Perspectives article highlights the roles of vascular smooth muscle, endothelial cells and perivascular innervation of cerebral arteries in the initiation and progression of, and recovery from, ischaemic stroke. The concept of the vascular neural network-which includes cerebral arteries, arterioles, and downstream neuronal and glial cell types and structures-is introduced as the fundamental component affected by stroke pathophysiology. The authors also propose that the vascular neural network should be considered the main target for future therapeutic intervention after cerebrovascular insult. Zhang, J. H. et al. Nat. Rev. Neurol. 8, 711-716 (2012); published online 16 October 2012; doi:10.1038/nrneurol.2012.210 (12/2012) (link)
  • Ajao D O, Pop V, Kamper J E, Adami A, Rudobeck E, . . . Badaut J. (2012). Traumatic Brain Injury in Young Rats Leads to Progressive Behavioral Deficits Coincident with Altered Tissue Properties in Adulthood. Journal of Neurotrauma, 29(11), 2060-2074. Traumatic brain injury (TBI) affects many infants and children, and results in enduring motor and cognitive impairments with accompanying changes in white matter tracts, yet few experimental studies in rodent juvenile models of TBI (jTBI) have examined the timeline and nature of these deficits, histologically and functionally. We used a single controlled cortical impact (CCI) injury to the parietal cortex of rats at post-natal day (P) 17 to evaluate behavioral alterations, injury volume, and morphological and molecular changes in gray and white matter, with accompanying measures of electrophysiological function. At 60 days post-injury (dpi), we found that jTBI animals displayed behavioral deficits in foot-fault and rotarod tests, along with a left turn bias throughout their early developmental stages and into adulthood. In addition, anxiety-like behaviors on the zero maze emerged in jTBI animals at 60 dpi. The final lesion constituted only similar to 3% of brain volume, and morphological tissue changes were evaluated using MRI, as well as immunohistochemistry for neuronal nuclei (NeuN), myelin basic protein (MBP), neurofilament-200 (NF200), and oligodendrocytes (CNPase). White matter morphological changes were associated with a global increase in MBP immunostaining and reduced compound action potential amplitudes at 60 dpi. These results suggest that brain injury early in life can induce long-term white matter dysfunction, occurring in parallel with the delayed development and persistence of behavioral deficits, thus modeling clinical and longitudinal TBI observations. (07/2012) (link)
  • Hartman R E, Kamper J E, Goyal R, Stewart J M, & Longo L D. (2012). Motor and cognitive deficits in mice bred to have low or high blood pressure. Physiology & Behavior, 105(4), 1092-1097. Deviations from normal blood pressure can lead to a number of physiological and behavioral complications. We tested the hypothesis that hyper- or hypotension is associated with significant differences in motor activity and coordination, anxiety levels, and spatial learning and memory in male and female mice. Compared to normotensive control mice, hypertensive mice were hyperactive and their performance was significantly worse on the rotarod (males only), cued learning (males only), spatial learning/re-learning, and spatial memory. Hypotensive mice of both genders swam more slowly and performed even worse than hypertensive mice on the rotarod, cued learning, spatial learning/re-learning, and spatial memory tasks. Across all phenotypes, females were generally more active than males in the open field and exhibited more anxiety-like behaviors in the elevated zero maze. Alterations in hemodynamics and/or neurovascular unit function may account for the observed behavioral changes in the hypo- and hypertensive mice. (C) 2011 Elsevier Inc. All rights reserved. (02/2012) (link)
  • Bertolizio G, Bissonnette B, Mason L, Ashwal S, Hartman R, Marcantonio S, & Obenaus A. (2011). Effects of hemodilution after traumatic brain injury in juvenile rats. Pediatric Anesthesia, 21(12), 1198-1208. Background: Normovolemic hemodilution (HD) in adult animal studies has shown exacerbation of traumatic brain injury (TBI) lesion volumes. Similar studies in juvenile rats have not been reported and outcomes are likely to be different. This study investigated the effects of normovolemic hemodilution (21% hematocrit) in a juvenile TBI (jTBI) model. Methods: Twenty 17-day-old rats underwent moderate cortical contusion impact injury (CCI) and were divided into four groups: CCI/hemodilution (HD) (group HD), CCI/no HD (group C), Sham/HD (group SHD), and Sham/no HD (group S). Regional laser Doppler flowmetry (LDF), edema formation (MRI-T2WI), water mobility assessed using diffusion weighted imaging (MRI-DWI), open field activity tests, and histological analyses were evaluated for lesion characteristics. Results: Hemodilution significantly increased blood flow in the HD compared to the C group after TBI. T2WI revealed a significantly increased extravascular blood volume in HD at 1, 7, and 14 days post-CCI. Edematous tissue and total contusional lesion volume were higher in HD-treated animals at 1 and 14 days. DWI revealed that HD, SHD, and C groups had elevated water mobility compared to S groups in the ipsilateral cortex and striatum. Histology showed a larger cortical lesion in the C than HD group. Open field activity was increased in HD, C, and SHD groups compared to the S group. Conclusions: Hemodilution results in significant brain hyperemia with increased edema formation, extravascular blood volume, and water mobility after jTBI. Hemodilution results in less cortical damage but did not alter behavior. Hemodilution is likely not to be clinically beneficial following jTBI. (12/2011) (link)
  • Hartman R E. (2011). A Brief History of Behavioral Assessment Following Experimental Traumatic Brain Injury in Juveniles. Translational Stroke Research, 2(4), 433-437. This review focuses on assessment of behavioral outcomes following traumatic brain injury in juvenile animal models. In the 15 years since the first publication in this field, the majority of studies have used rats roughly equivalent to human toddlers in terms of brain development. Few studies have tested ages closer to human neonates, and fewer have assessed ages closer to human adolescents. Closed head impact has been the most commonly used model, causing relatively consistent motor and cognitive deficits. Additionally, closed head impacts of a more severe nature have generally led to behavioral deficits of a more severe nature. Impact models (both closed and open skull) have produced more severe deficits in younger animals than in older animals, similar to patterns observed in juvenile humans with traumatic brain injury. In contrast, the fluid percussion model has produced relatively subtle deficits that did not get worse with a more severe injury and were worse for older animals than younger animals. Most of the studies have looked at relatively short postinjury time points, and none so far have assessed behavior in old adult animals injured as juveniles. The review ends with a discussion of possible directions for future animal research into juvenile traumatic brain injury. (12/2011) (link)
  • Chen, W., Ma, Q., Suzuki, H., Hartman, R., Tang, J., & Zhang, J. (2011). Osteopontin reduced hypoxia-ischemia neonatal brain injury by suppression of apoptosis in a rat pup model. Stroke, 42(3), 764-769.   (09/2011)
  • Bertolizio G, Bissonnette B, Mason L, Ashwal S, Hartman R, Marcantonio S, Obenaus A. (2011) Effects of hemodilution after traumatic brain injury in juvenile rats. Paediatr Anaesth (09/2011)
  •  Lekic, T., Manaenko, A., Rolland, W., Virbel, K., Hartman, R., Tang, J., Zhang, J.H. (2011) Neuroprotection by melatonin after germinal matrix hemorrhage in neonatal rats. Acta Neurochir Suppl, 111, 201-206.   (09/2011)
  • Lekic, T., Rolland, W., Hartman, R., Kamper, J., Suzuki, H., & Tang, J. (2011). Characterization of the brain injury, neurobehavioral profiles and histopathology in a rat model of cerebellar hemorrhage. Experimental Neurology 227, 96-103.   (09/2011)
  • Obenaus, A., Dilmac, N., Tone, B., Tian, H.R., Hartman, R.E., Digicaylioglu, M., Snyder, E.Y., & Ashwal, S. (2011). Long-Term magnetic resonance imaging of stem cells in neonatal ischemic injury. Annals of Neurology (08/2011)
  • Chen W, Ma Q, Suzuki H, Hartman R, Tang J, & Zhang J H. (2011). Osteopontin reduced hypoxia-ischemia neonatal brain injury by suppression of apoptosis in a rat pup model. Stroke, 42(3), 764-9. BACKGROUND AND PURPOSE: Osteopontin (OPN) is neuroprotective in ischemic brain injuries in adult experimental models; therefore, we hypothesized that OPN would provide neuroprotection and improve long-term neurological function in the immature brain after hypoxic-ischemic (HI) injury. METHODS: HI was induced by unilateral ligation of the right carotid artery followed by hypoxia (8% O(2) for 2 hours) in postnatal Day 7 rats. OPN (0.03 mug or 0.1 mug) was injected intracerebroventricularly at 1 hour post-HI. Temporal expression of endogenous OPN was evaluated in the normal rat brain at the age of 0, 4, 7, 11, 14, and 21 days and in the ipsilateral hemisphere after HI. The effects of OPN were evaluated using 2-3-5-triphenyl tetrazolium chloride staining, apoptotic cell death assay, and cleaved caspase-3 expression. Neurological function was assessed by the Morris water maze test. RESULTS: Endogenous OPN expression in the brain was the highest at the age of 0 day with continuous reduction until the age of 21 days during development. After HI injury, endogenous OPN expression was increased and peaked at 48 hours. Exogenous OPN decreased infarct volume and improved neurological outcomes 7 weeks after HI injury. OPN-induced neuroprotection was blocked by an integrin antagonist. CONCLUSIONS: OPN-induced neuroprotection was associated with cleaved-caspase-3 inhibition and antiapoptotic cell death. OPN treatment improved long-term neurological function against neonatal HI brain injury. (03/2011) (link)
  • Obenaus A, Dilmac N, Tone B, Tian H R, Hartman R, . . . Ashwal S. (2011). Long-Term Magnetic Resonance Imaging of Stem Cells in Neonatal Ischemic Injury. Annals of Neurology, 69(2), 282-291. Objective: Quantitative magnetic resonance imaging (MRI) can serially and noninvasively assess the degree of injury in rat pup models of hypoxic ischemic injury (HII). It can also noninvasively monitor stem cell migration following iron oxide prelabeling. Reports have shown that neural stem cells (NSCs) may help mediate neuroprotection or stimulate neuroreparative responses in adult and neonatal models of ischemic injury. We investigated the ability of high-field MRI to monitor and noninvasively quantify the migration, proliferation, and location of iron oxide-labeled NSCs over very long time periods (58 weeks) in real time while contemporaneously correlating this activity with the evolving severity and extent of neural damage. Methods: Labeled clonal murine NSCs (mNSCs) were implanted 3 days after unilateral HII in 10-day-old rat pups into the contralateral striatum or ventricle. We developed methods for objectively quantifying key aspects of dynamic NSC behavior (eg, viability; extent, and speed of migration; degree of proliferation; extent of integration into host parenchyma). MRI images were validated with histological and immunohistochemical assessments. Results: mNSCs rapidly migrated (100 mu m/day) to the lesion site. Chains of migrating NSCs were observed in the corpus callosum. In pups subjected to HII, though not in intact control animals, we observed a 273% increase in the MR-derived volume of mNSCs 4 weeks after implantation (correlating with the known proliferative behavior of endogenous and exogenous NSCs) that slowly declined over the 58-week time course, with no adverse consequences. Large numbers of now quiescent mNSCs remained at the site of injury, many retaining their iron oxide label. Interpretation: Our studies demonstrate that MRI can simultaneously monitor evolving neonatal cerebral injury as well as NSC migration and location. Most importantly, it can noninvasively monitor proliferation dynamically for prolonged time periods. To be able to pursue clinical trials in newborns using stem cell therapies it is axiomatic that safety be insured through the long-term real time monitoring of cell fate and activity, particularly with regard to observing unanticipated risks to the developing brain. This study supports the feasibility of reliably using MRI for this purpose. ANN NEUROL 2011;69:282-291 (02/2011) (link)
  • Lekic T, Rolland W, Hartman R, Kamper J, Suzuki H, Tang J, & Zhang J H. (2011). Characterization of the brain injury, neurobehavioral profiles, and histopathology in a rat model of cerebellar hemorrhage. Exp Neurol, 227(1), 96-103. Spontaneous cerebellar hemorrhage (SCH) represents approximately 10% of all intracerebral hemorrhage (ICH) and is an important clinical problem of which little is known. This study stereotaxically infused collagenase (type VII) into the deep cerebellar paramedian white matter, which corresponds to the most common clinical injury region. Measures of hemostasis (brain water, hemoglobin assay, Evans blue, collagen-IV, ZO-1, and MMP-2 and MMP-9) and neurodeficit were quantified 24 hours later (Experiment 1). Long-term functional outcomes were measured over 30 days using the ataxia scale (modified Luciani), open field, wire suspension, beam balance, and inclined plane (Experiment 2). Neurocognitive ability was assessed on the third week using the rotarod (motor learning), T maze (working memory), and water maze (spatial learning and memory) (Experiment 3), followed by a histopathological analysis 1 week later (Experiment 4). Stereotaxic collagenase infusion caused dose-dependent elevations in brain edema, neurodeficit, hematoma volume, and blood-brain barrier rupture, while physiological variables remained stable. Most functional outcomes normalized by the third week, while neurocognitive testing showed deficits parallel to the cystic-cavitary lesion at 30 days. All animals survived until sacrifice, and obstructive hydrocephalus did not develop. These results suggest that the model can generate important translational information about this subtype of ICH and could be used for future investigations of therapeutic mechanisms after cerebellar hemorrhage. (01/2011) (link)
  • Lekic T, Manaenko A, Rolland W, Virbel K, Hartman R, Tang J, & Zhang J H. (2011). Neuroprotection by melatonin after germinal matrix hemorrhage in neonatal rats. Acta Neurochir Suppl, 111, 201-6. BACKGROUND: Germinal matrix hemorrhage (GMH) is a devastating neurological disorder of very low birth weight premature infants that leads to post-hemorrhagic hydrocephalus, cerebral palsy, and mental retardation. Melatonin is a potent antioxidant known to reverse free-radical mediated injury in the brain. This study investigated the effect of melatonin treatment after GMH injury. METHODS: Clostridial collagenase was infused into the right germinal matrix region of neonatal rats with stereotaxic technique. Cognitive function, sensorimotor ability, cerebral, cardiac and splenic growths were measured in juvenile animals. RESULTS: Systemic melatonin treatment ameliorated cognitive and sensorimotor dysfunction at the juvenile developmental stage. This hormone also normalized brain atrophy, splenomegaly, and cardiac hypertrophy consequences at 1 month after injury. CONCLUSION: This study supports the role of free radicals in acute neonatal hemorrhagic brain injury. Melatonin is an effective antioxidant that can protect the infant's brain from the post-hemorrhagic consequences of mental retardation and cerebral palsy. Further mechanistic studies are warranted to determine the mechanisms behind these neuroprotective effects. (2011) (link)
  • Lekic T, Hartman R, Rojas H, Manaenko A, Chen W, . . . Zhang J H. (2010). Protective effect of melatonin upon neuropathology, striatal function, and memory ability after intracerebral hemorrhage in rats. J Neurotrauma, 27(3), 627-37. Since free radicals play a role in the mechanisms of brain injury after hemorrhagic stroke, the effect of melatonin (a potent antioxidant and free-radical scavenger) on outcomes was investigated after intracerebral hemorrhage (ICH) in rats. ICH was induced by clostridial collagenase infusion into the right caudate putamen, and several time points and doses of melatonin were studied. Brain edema and neurological function at 24 h were unchanged in comparison with vehicle-treated groups, in spite of oxidative stress reductions. Repeated treatment with the lower dose of melatonin (5 mg/kg) given at 1 h and every 24 h thereafter for 3 days after ICH, led to normalization of striatal function and memory ability over the course of 8 weeks, and less brain atrophy 2 weeks later. These results suggest that melatonin is safe for use after ICH, reduces oxidative stress, provides brain protection, and could be used for future investigations of free radical mechanisms after cerebral hemorrhage. (03/2010) (link)
  • Lekic, T., Hartman, R.E., Rojas, H., Manaenko, A., Chen, W., Ayer, R., Tang, J., & Zhang, J.H. (2010) Protective effect of melatonin upon neuropathology, striatal function, and memory ability after intracerebral hemorrhage in rats. Journal of Neurotrauma, 27(3), 627-37.   (01/2010)
  • Chen, W., Hartman, R.E., Ayer, R., Marcantonio, S., Kamper, J., Tang, J., Zhang, J. (2009). Matrix metalloproteinases inhibition provides neuroprotection against hypoxia-ischemia in the developing brain. Journal of Neurochemistry,   (12/2009)
  • Chen W, Hartman R, Ayer R, Marcantonio S, Kamper J, Tang J, & Zhang J H. (2009). Matrix metalloproteinases inhibition provides neuroprotection against hypoxia-ischemia in the developing brain. J Neurochem, 111(3), 726-36. The present study was designed to investigate the role of matrix metalloproteinases (MMPs) in the immature brain and the long term effects of early MMPs inhibition after hypoxic-ischemic (HI) injury. HI was induced by unilateral ligation of the right carotid artery followed by hypoxia (8% O(2) for 2 h) in P7 rat pups. GM6001, a broad spectrum MMPs inhibitor, was injected (50 mg/kg or 100 mg/kg) intraperitoneally at 2 h and 24 h after HI injury. Blood-brain barrier (BBB) integrity, brain edema, MMP-2/-9 activity, TIMP-1/-2 and tight junction protein (TJP) level were evaluated using IgG staining, Evan's blue extravasation, brain water content, zymography and western blot. Doxycycline, another MMPs inhibitor, was injected (10 mg/kg or 30 mg/kg) intraperitoneally at 2 h after HI, then BBB integrity and brain edema were measured at 48 h post-HI using brain water content measurement and IgG staining. The long-term effects of early MMPs inhibition (GM6001, 100 mg/kg) were evaluated by neurobehavioral tests, body weight, and brain atrophy measurement. GM6001 attenuated brain edema and BBB disruption at the dosage of 100 mg/kg. MMP-2 activity increased at 24 h and peaked at 48 h after HI, whereas MMP-9 activity peaked at 24 h and tapered by 48 h after HI. MMP-9/-2 activities were significantly attenuated by GM6001 at 24 h and 48 h after HI. The degradation of TJPs (ZO-1 and occludin) at 48 h after HI was reversed by GM6001 treatment. Early MMPs inhibition had long-term effects that attenuated ipsilateral brain tissue loss, and improved neurobehavioral outcomes after HI. These results suggest that early MMPs inhibition with a broad-spectrum inhibitor provides both acute and long-term neuroprotection in the developing brain by reducing TJPs degradation, preserving BBB integrity, and ameliorating brain edema after neonatal HI injury. (11/2009) (link)
  • Hartman R, Lekic T, Rojas H, Tang J, & Zhang J H. (2009). Assessing functional outcomes following intracerebral hemorrhage in rats. Brain Res, 1280, 148-57. Translational neuroprotective and drug development studies need to be gauged against well-characterized functional outcomes, including motor, sensory and cognitive domains. Since intracerebral hemorrhage (ICH) causes dramatic neurological and cognitive deficits in humans, we hypothesized that ICH would result in prolonged motor-sensory and learning/memory deficits in rats. Neurological tests of sensorimotor functions were performed before ICH, 1-3 days and 10 weeks after ICH. Water maze, open field, and rotarod performance was tested 2 and 8 weeks after ICH. Early neurological evaluations revealed significant deficits, with almost full recovery by 10 weeks. The water maze revealed significant learning (but not motor) deficits at 2 weeks, but by 8 weeks, the learning deficits had diminished and significant motor deficits had emerged, coinciding with a drop in activity. The injured hemisphere showed significant atrophy at sacrifice. Therefore, ICH produced detectable cognitive and motor deficits in rats that evolved over a 10-week period, and thereby provides a suitable baseline for analysis of future therapeutic interventions following hemorrhagic stroke. (07/2009) (link)
  • Recker R, Adami A, Tone B, Tian H R, Lalas S, . . . Ashwal S. (2009). Rodent neonatal bilateral carotid artery occlusion with hypoxia mimics human hypoxic-ischemic injury. Journal of Cerebral Blood Flow and Metabolism, 29(7), 1305-1316. We report a new clinically relevant model of neonatal hypoxic-ischemic injury in a 10-day-old rat pup. Bilateral carotid artery occlusion and 8% hypoxia (1 to 15 mins, BCAO-H) was induced with varying degrees of injury (mild, moderate, severe), which was quantified using magnetic resonance imaging including diffusion-weighted and T2-weighted imaging at 24 h and 21/28 days. We developed a magnetic resonance imaging-based rat pup severity score and compared 3D ischemic injury volumes/rat pup severity score with histology and behavioral testing. At 24 h, hypoxic-ischemic injury was observed in 17/27 animals; long-term survival was 81%. Magnetic resonance imaging lesion volumes did not correlate with hypoxia duration but correlated with rat pup severity score, which was used to classify animals into mild (n = 21), moderate (n = 6), and severe (n = 10) groups with average brain lesion volumes of 0.9%, 33.2%, and 56.3%, respectively. Histology confirmed lesion location and histologic scoring correlated with the rat pup severity score. We also found excellent correlation between injury severity and multiple behavioral tasks. Bilateral carotid artery occlusion and hypoxia in the P10 rat pup is an excellent model of neonatal hypoxic-ischemic injury because it induces diffuse global injury similar to the term infant. This model can produce graded injury severity, similar to that seen in human neonates, but manipulation with hypoxia duration is unpredictable. Journal of Cerebral Blood Flow & Metabolism (2009) 29, 1305-1316; doi: 10.1038/jcbfm.2009.56; published online 13 May 2009 (07/2009) (link)
  • Hartman, R.E., Shah, A., Fagan, A.M., Schwetye, K.E., Parsadanian, M., Schulman, R.N., Finn, M.B., & Holtzman, D.M.. "Pomegranate juice decreases amyloid load and improves behavior in a mouse model of Alzheimers disease." Neurobiology of Disease 24. (2006): 506-515. Although there are no proven ways to delay onset or slow progression of Alzheimer''s disease (AD), studies suggest that diet can affect risk. Pomegranates contain very high levels of antioxidant polyphenolic substances as compared to other fruits and vegetables. Polyphenols have been shown to be neuroprotective in different model systems. We asked whether dietary supplementation with pomegranate juice (PJ) would influence behavior and AD-like pathology in a transgenic mouse model. Transgenic mice (APP(sw)/Tg2576) received either PJ or sugar water control from 6 to 12.5months of age. PJ-treated mice learned water maze tasks more quickly and swam faster than controls. Mice treated with PJ had significantly less (approximately 50%) accumulation of soluble Abeta(42) and amyloid deposition in the hippocampus as compared to control mice. These results suggest that further studies to validate and determine the mechanism of these effects, as well as whether substances in PJ may be useful in AD, should be considered. (12/2006) (link)
  • Wahrle, S.E., Jiang, H., Parsadanian, M., Hartman, R.E., Bales, K.R., Paul, S.M., & Holtzman, D.M.(2005). Deletion of Abca1 increases Aβ deposition in the PDAPP transgenic mouse model of Alzheimer’s disease. Journal of Biological Chemistry, 280(52), 43236-43242.   (12/2005)
  • Complete, updated list of publications in NCBI Bibliography: http://www.ncbi.nlm.nih.gov/sites/myncbi/1Zqja6bq68j/bibliography/46707223/public/?sort=date&direction=ascending (Present)

Abstract

  • Sorensen D, Ajao D, Kamper J, Hartman R, Obenaus A, & Badaut J. (2013). EARLY NEUROVASCULAR UNIT CHANGES ARE CORRECTED VIA JNK INHIBITION AFTER JUVENILE TRAUMATIC BRAIN INJURY. Journal of Neurotrauma, 30(15), A132-A132. (08/2013)
  • Truong H N, Wolfe C, Hartman R E, Obenaus A, & Blood A B. (2013). NEUROPROTECTIVE EFFECTS OF NITRITE AGAINST HYPOXIC ISCHEMIC BRAIN INJURY IN NEWBORN RAT PUPS. Journal of Investigative Medicine, 61(1), 168-168. (01/2013)
  • Donovan B S V, Bianchi B S A, Hartman R, Bhanu B, Carson M J, & Obenaus A. (2012). COMPUTATIONAL ANALYSIS OF INJURED TISSUE FOLLOWING REPETITIVE MILD TRAUMATIC BRAIN INJURY. Journal of Neurotrauma, 29(10), A159-A160. (07/2012)
  • Badaut J, Ajao D, Kamper J, Pop V, Ashwal S, Hartman R, & Obenaus A. (2011). INHIBITION OF THE JNK PATHWAY IMPROVES THE LONG-TERM FUNCTIONAL RECOVERY AFTER JUVENILE TRAUMATIC BRAIN INJURY. Journal of Neurotrauma, 28(6), A6-A6. (06/2011)
  • (NON-PEER REVIEWED) AQP4 and JNK inhibition together reduce edema and excitotoxic injury in juvenile traumatic brain injury   (2010 - Present)
  • Tang J, Fathali N, Lekie T, Hartman R, Chen W, & Zhang J H. (2009). GRANULOCYTE-COLONY STIMULATING FACTOR-INDUCED NEUROPROTECTION IN ANIMAL MODELS OF BRAIN INJURY. Journal of Neurochemistry, 110, 155-156. (09/2009)
  • Kamper J E, Brody D L, Parsadanian A, Esparza T E, Schwetye K E, . . . Hartman R E. (2009). LONG-TERM BEHAVIORAL ASSESSMENT IN TWO MOUSE MODELS OF JUVENILE TBI. Journal of Neurotrauma, 26(8), A51-A51. (08/2009)