R E Mrak

University of Toledo, Toledo, Ohio, United States

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Publications (125)463.83 Total impact

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    ABSTRACT: Alzheimer's disease (AD) is characterized neuropathologically by the presence of amyloid plaques, neuritic plaques, and neurofibrillary tangles (NFTs). These lesions occur not only in demented individuals with AD but also in non-demented persons. In non-demented individuals, amyloid and neuritic plaques are usually accompanied with NFTs and are considered to represent asymptomatic or preclinical AD (pre-AD) pathology. Here, we defined and characterized neuropathological differences between clinical AD, non-demented pre-AD, and non-AD control cases. Our results show that clinical AD may be defined as cases exhibiting late stages of NFT, amyloid, and neuritic plaque pathology. This is in contrast to the neuropathological changes characteristic of pre-AD, which display early stages of these lesions. Both AD and pre-AD cases often exhibit cerebral amyloid angiopathy (CAA) and granulovacuolar degeneration (GVD), and when they do, these AD-related pathologies were at early stages in pre-AD cases and at late stages in symptomatic AD. Importantly, NFTs, GVD, and CAA were also observed in non-AD cases, i.e., in cases without amyloid plaque pathology. Moreover, soluble and dispersible, high-molecular-weight amyloid β-protein (Aβ) aggregates detected by blue-native polyacrylamide gel electrophoresis were elevated in clinical AD compared to that in pre-AD and non-AD cases. Detection of NFTs, GVD, and CAA in cases without amyloid plaques, presently classified as non-AD, is consistent with the idea that NFTs, GVD, and CAA may precede amyloid plaque pathology and may represent a pre-amyloid plaque stage of pre-AD not yet considered in the current recommendations for the neuropathological diagnosis of AD. Our finding of early stages of AD-related NFT, amyloid, and GVD pathology provides a more clear definition of pre-AD cases that is in contrast to the changes in clinical AD, which is characterized by late stages of these AD-related pathologies. The observed elevation of soluble/dispersible Aβ aggregates from pre-AD compared to that in AD cases suggests that, in addition to more widespread AD-related pathologies, soluble/dispersible Aβ aggregates in the neuropil play a role in the conversion of pre-AD to clinical AD.
    European Archives of Psychiatry and Clinical Neuroscience 09/2013; · 3.36 Impact Factor
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    Sue T Griffin, Robert E Mrak
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    ABSTRACT: The editors of Journal of Neuroinflammation would like to thank all the reviewers who have contributed to the journal in Volume 9 (2012).
    Journal of Neuroinflammation 02/2013; 10(1):17. · 4.35 Impact Factor
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    ABSTRACT: Precocious development of Alzheimer-type neuropathological changes in epilepsy patients, especially in APOE ϵ4,4 carriers is well known, but not the ways in which other APOE allelic combinations influence this outcome. Frozen and paraffin-embedded tissue samples resected from superior temporal lobes of 92 patients undergoing temporal lobectomies as a treatment for medication-resistant temporal lobe epilepsy were used in this study. To determine if epilepsy-related changes reflect those in another neurological condition, analogous tissue samples harvested from 10 autopsy-verified Alzheimer brains, and from 10 neurologically and neuropathologically normal control patients were analyzed using immunofluorescence histochemistry, western immunoblot, and real-time PCR to determine genotype effects on neuronal number and size, neuronal and glial expressions of amyloid β (Aβ) precursor protein (βAPP), Aβ, apolipoprotein E (ApoE), S100B, interleukin-1α and β, and α and β secretases; and on markers of neuronal stress, including DNA/RNA damage and caspase 3 expression. Allelic combinations of APOE influenced each epilepsy-related neuronal and glial response measured as well as neuropathological change. APOE ϵ3,3 conferred greatest neuronal resilience denoted as greatest production of the acute phase proteins and low neuronal stress as assessed by DNA/RNA damage and caspase-3 expression. Among patients having an APOE ϵ2 allele, none had Aβ plaques; their neuronal sizes, like those with APOE ϵ3,3 genotype were larger than those with other genotypes. APOE ϵ4,4 conferred the weakest neuronal resilience in epilepsy as well as in Alzheimer patients, but there were no APOE genotype-dependent differences in these parameters in neurologically normal patients. Our findings provide evidence that the strength of the neuronal stress response is more related to patient APOE genotype than to either the etiology of the stress or to the age of the patient, suggesting that APOE genotyping may be a useful tool in treatment decisions.
    Acta neuropathologica communications. 01/2013; 1(1):41.
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    ABSTRACT: Epilepsy is associated with precocious development of Alzheimer-type neuropathological changes, including appearance of senile plaques, neuronal loss and glial activation. As inheritance of APOE ε4 allele(s) is reported to favor this outcome, we sought to investigate neuronal and glial responses that differ according to APOE genotype. With an eye toward defining ways in which APOE ε3 alleles may foster neuronal well-being in epilepsy and/or APOE ε4 alleles exacerbate neuronal decline, neuronal and glial characteristics were studied in temporal lobectomy specimens from epilepsy patients of either APOE ε4,4 or APOE ε3,3 genotype. Tissue and/or cellular expressions of interleukin-1 alpha (IL-1α), apolipoprotein E (ApoE), amyloid β (Aβ) precursor protein (βAPP), synaptophysin, phosphorylated tau, and Aβ were determined in frozen and paraffin-embedded tissues from 52 APOE ε3,3 and 7 APOE ε4,4 (0.25 to 71 years) epilepsy patients, and 5 neurologically normal patients using Western blot, RT-PCR, and fluorescence immunohistochemistry. Tissue levels of IL-1α were elevated in patients of both APOE ε3,3 and APOE ε4,4 genotypes, and this elevation was apparent as an increase in the number of activated microglia per neuron (APOE ε3,3 vs APOE ε4,4 = 3.7 ± 1.2 vs 1.5 ± 0.4; P < 0.05). This, together with increases in βAPP and ApoE, was associated with apparent neuronal sparing in that APOE ε4,4 genotype was associated with smaller neuron size (APOE ε4,4 vs APOE ε3,3 = 173 ± 27 vs 356 ± 45; P ≤ 0.01) and greater DNA damage (APOE ε4,4 vs APOE ε3,3 = 67 ± 10 vs 39 ± 2; P = 0.01). 3) Aβ plaques were noted at early ages in our epilepsy patients, regardless of APOE genotype (APOE ε4,4 age 10; APOE ε3,3 age 17). Our findings of neuronal and glial events, which correlate with lesser neuronal DNA damage and larger, more robust neurons in epilepsy patients of APOE ε3,3 genotype compared to APOE ε4,4 genotype carriers, are consistent with the idea that the APOE ε3,3 genotype better protects neurons subjected to the hyperexcitability of epilepsy and thus confers less risk of AD (Alzheimer's disease).Please see related article: http://www.biomedcentral.com/1741-7015/10/36.
    BMC Medicine 04/2012; 10:35. · 7.28 Impact Factor
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    Robert E Mrak
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    ABSTRACT: Microglia have long been noted to be present and activated in Alzheimer brain. Demonstrations that these microglia are associated with the specific lesions of Alzheimer disease-Aβ plaques and neurofibrillary tangles-and that these microglia overexpress the potent proinflammatory cytokine interleukin-1 led to the recognition of a potential pathogenic role for these cells in initiation and progression of disease. Activated, cytokine-overexpressing microglia are near-universal components of Aβ plaques at early (diffuse) and mid (neuritic) stages of progression in Alzheimer brain, and only decline in end-stage, dense core plaques. They correlate with plaque distribution across cerebral cortical cytoarchitectonic layers and across brain regions. They also show close associations with tangle-bearing neurons in Alzheimer brain. Microglial activation is a consistent feature in conditions that confer increased risk for Alzheimer disease or that are associated with accelerated appearance of Alzheimer-type neuropathological changes. These include normal ageing, head injury, diabetes, heart disease, and chronic intractable epilepsy. The neuropathological demonstration of microglial activation in Alzheimer brain and in Alzheimer-related conditions opened the field of basic and applied investigations centered on the idea of a pathogenically important neuroinflammatory process in Alzheimer disease.
    International journal of Alzheimer's disease. 01/2012; 2012:165021.
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    ABSTRACT: We have previously outlined functional interactions, including feedback cycles, between several of the gene products implicated in the pathogenesis of Alzheimer's disease. A number of Alzheimer-related stressors induce neuronal expression of apolipoprotein E (ApoE), β-amyloid precursor protein (βAPP), and fragments of the latter such as amyloid β-peptide (Aβ) and secreted APP (sAPP). These stressors include interleukin-1 (IL-1)-mediated neuroinflammation and glutamate-mediated excitotoxicity. Such circumstances are especially powerful when they transpire in the context of an APOE ε4 allele. Semi-quantitative immunofluorescence imaging was used to analyze rat brains implanted with IL-1β slow-release pellets, sham pellets, or no pellets. Primary neuronal or NT2 cell cultures were treated with IL-1β, glutamate, Aβ, or sAPP; relative levels of ApoE mRNA and protein were measured by RT-PCR, qRT-PCR, and western immunoblot analysis. Cultures were also treated with inhibitors of multi-lineage kinases--in particular MAPK-p38 (SB203580), ERK (U0126), or JNK (SP600125)--prior to exposure of cultures to IL-1β, Aβ, sAPP, or glutamate. Immunofluorescence of tissue sections from pellet-implanted rats showed that IL-1β induces expression of βAPP, IL-1α, and ApoE; the latter was confirmed by western blot analysis. These protein changes were mirrored by increases in their mRNAs, as well as in those encoding IL-1β, IL-1β-converting enzyme (ICE), and tumor necrosis factor (TNF). IL-1β also increased ApoE expression in neuronal cultures. It stimulated release of sAPP and glutamate in these cultures too, and both of these agents--as well as Aβ--stimulated ApoE expression themselves, suggesting that they may contribute to the effect of IL-1β on ApoE levels. Inhibitors of MAPK-p38, ERK, and JNK inhibited ApoE induction by all these agents except glutamate, which was sensitive only to inhibitors of ERK and JNK. Conditions of glial activation and hyperexcitation can elevate proinflammatory cytokines, ApoE, glutamate, βAPP, and its secreted fragments. Because each of these factors promotes glial activation and neuronal hyperexcitation, these relationships have the potential to sustain self-propagating neurodegenerative cycles that could culminate in a progressive neurodegenerative disorder such as Alzheimer's disease.
    Journal of Neuroinflammation 12/2011; 8:175. · 4.35 Impact Factor
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    K E Funk, R E Mrak, J Kuret
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    ABSTRACT: Granulovacuolar degeneration involves the accumulation of large, double membrane-bound bodies within certain neurones during the course of Alzheimer's disease (AD) and other adult-onset dementias. Because of the two-layer membrane morphology, it has been proposed that the bodies are related to autophagic organelles. The aim of this study was to test this hypothesis, and determine the approximate stage at which the pathway stalls in AD. Spatial colocalization of autophagic and endocytic markers with casein kinase 1 delta, a marker for granulovacuolar degeneration (GVD) bodies, was evaluated in hippocampal sections prepared from post mortem Braak stage IV and V AD cases using double-label confocal fluorescence microscopy. GVD bodies colocalized weakly with early-stage autophagy markers LC3 and p62, but strongly with late-stage marker lysosome-associated membrane protein 1 (LAMP1), which decorated their surrounding membranes. GVD bodies also colocalized strongly with charged multivesicular body protein 2B (CHMP2B), which colocalized with the core granule, but less strongly with lysosomal marker cathepsin D. The resultant immunohistochemical signature suggests that granulovacuolar degeneration bodies (GVBs) do contain late-stage autophagic markers, and accumulate at the nexus of autophagic and endocytic pathways. The data further suggest that failure to complete autolysosome formation may be an important correlate of GVB accumulation.
    Neuropathology and Applied Neurobiology 10/2010; 37(3):295-306. · 4.84 Impact Factor
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    ABSTRACT: The deposition of amyloid beta-protein (Abeta) in the vessel wall, i.e., cerebral amyloid angiopathy (CAA), is associated with Alzheimer's disease (AD). Two types of CAA can be differentiated by the presence or absence of capillary Abeta-deposits. In addition, as in Alzheimer's disease, risk for capillary CAA is associated with the apolipoprotein E (APOE) epsilon4-allele. Because these morphological and genetic differences between the two types of AD-related CAA exist, the question arises as to whether there exist further differences between AD cases with and without capillary CAA and, if so, whether capillary CAA can be employed to distinguish and define specific subtypes of AD. To address this question, we studied AD and control cases both with and without capillary CAA to identify the following: (1) distinguishing neuropathological features; (2) alterations in perivascular protein expression; and (3) genotype-specific associations. More widespread Abeta-plaque pathology was observed in AD cases with capillary CAA than in those without. Expression of perivascular excitatory amino acid transporter 2 (EAAT-2/GLT-1) was reduced in cortical astrocytes of AD cases with capillary CAA in contrast to those lacking capillary Abeta-deposition and controls. Genetically, AD cases with capillary CAA were strongly associated with the APOE epsilon4 allele compared to those lacking capillary CAA and to controls. To further validate the existence of distinct types of AD we analyzed polymorphisms in additional apoE- and cholesterol-related candidate genes. Our results revealed an association between AD cases without capillary CAA (i.e., AD cases with CAA but lacking capillary CAA and AD cases without CAA) and the T-allele of the alpha(2)macroglobulin receptor/low-density lipoprotein receptor-related protein-1 (LRP-1) C766T polymorphism as opposed to AD cases with capillary CAA and non-AD controls. Taken together, these results indicate that AD cases with capillary CAA differ significantly from other AD cases both genetically and morphologically, thereby pointing to a specific capillary CAA-related and APOE epsilon4-associated subtype of AD.
    Acta Neuropathologica 08/2010; 120(2):169-83. · 9.73 Impact Factor
  • Shimin Hu, Robert E Mrak, Peter J Goldblatt
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    ABSTRACT: We report an unusual case of hepatocellular carcinoma with three histologically and immunohistochemically distinct components, arising in a noncirrhotic liver, with a pulmonary tumor embolus from one of the three components. The histological patterns of the three components were fibrolamellar, well-differentiated nodular, and pleomorphic. The immunophenotypes were, respectively CK7- /CK20- /Hep Par1+, CK7+ /CK20- /Hep Par1+, and CK7+ /CK20+ /Hep Par1-. The tumor in the pulmonary embolus showed only the morphological and immunohistochemical features of the pleomorphic component. This unusual case ofmetastasizing hepatocellular carcinoma with three distinct histologic components suggests that the histological and immunophenotype of the tumor might be useful in predicting metastatic potential.
    Connecticut medicine 02/2010; 74(2):79-83.
  • W. Sue T. Griffin, Robert E. Mrak
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    ABSTRACT: Improvements in modern hygiene and public health have resulted in decreased human contact with organisms associated with so-called ‘dirtier’ environs. These changes, in turn have led to an appreciation of the potential importance of such ‘friendly’ organisms toward proper development of the human immune system. Based on this, a novel hypothesis (the hygiene hypothesis) has been formulated. This idea suggests that a paucity of exposure to environmental pathogens retards proper immune system development, and consequently decreases its ability to effectively thwart a variety of effectors with degenerative consequences, such as those associated with chronic inflammatory responses in diseases as seemingly diverse as those of the gut and the brain. In this chapter, we review current information, including the potential contribution of inheritance to development of hypotheses regarding the pathogenesis of chronic neurodegenerative diseases, especially Alzheimer’s disease. We further explore ways in which the hygiene hypothesis and ideas in Darwinian medicine may play a role in the neuropathogenesis of these diseases.
    12/2009: pages 257-278;
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    ABSTRACT: Metabolic brain imaging is widely used to evaluate brain function and disease, and quantitative assays require local retention of compounds used to register changes in cellular activity. As labeled metabolites of [1- and 6-(14)C]glucose are rapidly released in large quantities during brain activation, this study evaluated release of metabolites and proteins through perivascular fluid flow, a pathway that carries solutes from brain to peripheral lymphatic drainage sites. Assays with [3,4-(14)C]glucose ruled out local oxidation of glucose-derived lactate as a major contributor of label loss. Brief infusion of [1-(14)C]glucose and D-[(14)C]lactate into the inferior colliculus of conscious rats during acoustic stimulation labeled the meninges, consistent with perivascular clearance of [(14)C]metabolites from interstitial fluid. Microinfusion of Evans blue albumin and amyloid-beta(1-40) (Abeta) caused perivascular labeling in the inferior colliculus, labeled the surrounding meninges, and Abeta-labeled-specific blood vessels in the caudate and olfactory bulb and was deposited in cervical lymph nodes. Efflux of extracellular glucose, lactate, and Abeta into perivascular fluid pathways is a normal route for clearance of material from the inferior colliculus that contributes to underestimates of brain energetics. Convergence of 'watershed' drainage to common pathways may facilitate perivascular amyloid plaque formation and pathway obstruction in Alzheimer's disease.
    Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism 09/2009; 30(1):162-76. · 5.46 Impact Factor
  • Robert E Mrak
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    ABSTRACT: A role for innate immunity in neurodegenerative diseases is now widely accepted, although debate continues over the relative contributions of these processes to disease progression and/or to disease amelioration. The idea that microglia and cytokines are important in neurodegeneration arose from neuropathological observations, especially in Alzheimer's disease. Microglia are invariant components of the Abeta plaques of Alzheimer's disease, where they show a waxing and waning of numbers, activation state, and cytokine expression during plaque progression. This is in contrast to diffuse Abeta deposits sometimes found in abundance in the brain of non-demented elderly individuals, which do not contain activated microglia. In Alzheimer's disease, plaque-associated astrocytes, which also produce paracrine mediators, show a pattern similar to that of microglia; and the associated plaque progression is accompanied by progressive damage to and loss of adjacent neurons. Further, activated microglia and astrocytes show a progressive pattern of association with neurofibrillary tangles. These observations, together with known functions of the involved cytokines, originally suggested a central role for immunological phenomena in driving disease progression in Alzheimer's disease. Further observations have extended these ideas to alpha-synuclein-based diseases (Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy) as well as other neurodegenerative diseases and conditions.
    Journal of Alzheimer's disease: JAD 08/2009; 18(3):473-81. · 4.17 Impact Factor
  • Murat Gokden, Robert E Mrak
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    ABSTRACT: Neoplasms consisting of pituitary adenoma and craniopharyngioma components are rare and are being increasingly recognized. Their histogenesis is not clear. Most represent collision tumors; others are difficult to assess. Here, we describe a pituitary adenoma with an intermingled craniopharyngioma component, without forming 2 distinct mass lesions or histologic delineation. Areas that suggest a transition between the 2 components were also present. It was clinically a nonfunctioning adenoma, which was also negative for pituitary hormones by immunohistochemistry. Its histogenesis and implications are discussed with a review of the literature.
    Human pathology 06/2009; 40(8):1189-93. · 3.03 Impact Factor
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    ABSTRACT: Cell membrane abnormalities due to changes in phospholipid (PL) composition and metabolism have been implicated in schizophrenia pathogenesis. That work has generally assessed membrane phospholipids from nonneural tissues such as erythrocytes and platelets. High-resolution (31)P NMR spectroscopy was used to characterize PLs of gray matter in postmortem brain for 20 schizophrenics, 20 controls, and 7 patients with other mental illnesses (psychiatric controls). Tissues from frontal, temporal, and occipital cortices were extracted with hexane-isopropanol, and (31)P NMR spectra were obtained in an organic-solvent system to resolve the major PL classes (based on headgroups) and subclasses (based on linkage at the sn - 1 position). Surprisingly, repeated-measures multivariate analysis of variance revealed no overall differences among the groups. There were no significant differences (P < .05) among the three groups for any individual PL subclass, including lysophospholipids. The sum of all phosphatidylethanolamine headgroups was significantly lower for schizophrenics than for controls or psychiatric controls in the frontal cortex. The present results are minimally correlated with previous results for aqueous PL metabolites on these same samples. The metabolite changes measured by in vivo (31)P MRS in schizophrenia do not appear to reflect PL concentration changes. The present results offer very little support for the phospholipid hypothesis of schizophrenia.
    Magnetic Resonance in Medicine 12/2008; 61(1):28-34. · 3.27 Impact Factor
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    ABSTRACT: Theories regarding the initiation and progression of Alzheimer disease (AD) often consider potential roles played by elevations of beta-amyloid precursor protein (betaAPP). Because it is the source of amyloid beta-peptide, betaAPP may simply contribute more pathogenic stimulus when elevated; some analyses have, however, reported a decline in betaAPP in AD. We found a progressive increase in neuronal betaAPP expression with increasing age in the brains of nondemented individuals, whereas in AD patient samples, betaAPP antigenicity decreased in neuronal somata in a manner that correlated with accumulation of mature amyloid beta-peptide plaques. In contrast, apolipoprotein E (ApoE) expression correlated with accumulation of plaques, and even greater amounts of ApoE were detected in plaques. Induction of betaAPP by glutamate in neuronal cell cultures was found to depend upon ApoE levels or activity. Thus, elevations in expression of ApoE and betaAPP by cellular stresses are likely normally linked in vivo, and uncoupling of this link, or other pathologic events in AD initiation, may leave neurons with diminished betaAPP expression, which might in turn reduce their resistance to stressors.
    Journal of Neuropathology and Experimental Neurology 08/2008; 67(8):773-83. · 4.35 Impact Factor
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    ABSTRACT: Interleukin-1α-immunoreactive (IL-1α+) microglia are prominent components of neuritic plaques in Alzheimer's disease, and may be important in the evolution of neuritic plaques from diffuse amyloid deposits. Neuritic plaques show a characteristic distribution across cerebral regions and are absent in the cerebellum of patients with Alzheimer's disease. We used single- and dual-immunohistochemical labelling to investigate the possibility that the expression of IL-1α is correlated with this regional distribution of neuritic (tau 2-immunoreactive, tau 2+) plaques. In Alzheimer's disease, tau 2+ neuritic plaques occurred with increasing frequency in grey matter of frontal and occipital lobes, temporal lobe, and hippocampus. There were positive correlations between the regional patterns of distribution of activated IL-1α+ microglia and tau2+ neuritic plaques as well as between activated IL-1α+ microglia and activated astrocytes. No activated IL-1α+ microglia, tau 2+ neuritic plaques, or activated astrocyies were observed in cerebellum of these Alzheimer patients. These regional relationships between activated IL-1α+ microglia, tau 2+ neuritic plaques, and activated astrocytes, together with the established functions of IL-1, support a causal association between the overexpression of IL-1 and the evolution of β-amyloid deposits into neuritic plaques in Alzheimer's disease.
    Neuropathology and Applied Neurobiology 05/2008; 21(4):290 - 301. · 4.84 Impact Factor
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    ABSTRACT: Evidence has been accumulating that schizophrenia involves abnormalities in the composition and metabolism of cell membrane phospholipids (PLs) in the brain. In vivo 31P MRS has been used to measure the metabolic precursors and degradation products of PL metabolism in schizophrenia. Because in vivo line widths are substantially broader than in solution, only the broad phosphomonoester (PME) and phosphodiester bands, or partly resolved resonances of individual metabolites, are typically measured in vivo in the 31P spectrum. In addition to poor resolution, the relatively low signal-to-noise ratio (SNR) makes precise quantitation difficult. An alternative with substantially better resolution and precision for quantitation is high-resolution NMR spectroscopy of extracts of samples from postmortem brain. Here we determine absolute concentrations of the individual PL metabolites phosphocholine (pc), phosphoethanolamine (pe), glycerophosphocholine (gpc), and glycerophosphoethanolamine in aqueous extracts of tissue from frontal, temporal, and occipital cortex of postmortem brain for schizophrenics, controls, and patients with other mental illnesses (psychiatric controls [PC]) using high-resolution 31P NMR spectroscopy. For the complete groups, which included both males and females, there were no statistically significant differences for schizophrenics vs. controls for any of the four PL metabolites in any of the three brain regions. Trends (0.05 < P < 0.10) were noted for increased gpc in schizophrenia in all three regions. PC differed from both controls and schizophrenics in several measures. When only males were considered, gpc was significantly (P < 0.05) elevated in all three brain regions in schizophrenia.
    Magnetic Resonance in Medicine 04/2008; 59(3):469-74. · 3.27 Impact Factor
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    Robert E Mrak, W Sue T Griffin
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    ABSTRACT: Clinical dementia associated with the appearance of Lewy bodies in the cerebral cortex has been recognized for over 40 years. Until the 1990s, however, cortical Lewy body disease was thought to be a rare cause of dementia. At that time, the advent of sensitive and specific immunohistochemical techniques for highlighting these elusive structures led to the recognition of cortical Lewy body disease as a common substrate for clinical dementia. Current diagnostic criteria recognize dementia with Lewy bodies as a clinicopathological entity. Also recognized is the closely related (and perhaps biologically identical) entity of Parkinson's disease dementia, which differs from dementia with Lewy bodies only in the temporal sequence of appearance of clinical symptoms. The generic term "Lewy body disease" encompasses both entities. There is frequent and extensive overlap, both clinically and pathologically, between dementia with Lewy bodies and Alzheimer's disease. The two diseases share several genetic and environmental risk factors that have in common increased inflammatory states associated with increased disease risk. Moreover, pathological and experimental work has implicated the involvement of activated microglia and of microglia-derived interleukin-1 in the pathogenesis of the pathognomonic lesions of both diseases. Such neuroinflammatory processes may be the common link driving progression in both diseases and explaining the frequent overlap between the two diseases.
    Neuropsychiatric Disease and Treatment 11/2007; 3(5):619-25. · 2.00 Impact Factor
  • Robert E Mrak, W Sue T Griffin
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    ABSTRACT: Cortical Lewy body disease as a cause of dementia has been recognized for more than 40 years. Only in the past 15 to 20 years, however, has the true frequency of this entity come to be appreciated, primarily because of the advent of sensitive and specific immunohistochemical diagnostic techniques. We now know that there is frequent and extensive overlap, both clinically and pathologically, between Lewy body and Alzheimer diseases. Although some of this overlap may be attributable to common genetic and environmental risk factors, it is also now apparent that the 2 diseases share common neuroinflammatory mechanisms involving activation of microglia, overexpression of interleukin-1 and other inflammatory mediators, and inflammatory toxicity to neurons. Activated microglia are found in association with alpha-synuclein-containing neurons and glia in Parkinson disease, in dementia with Lewy bodies, and in multiple system atrophy, and these associations are reminiscent of microglial associations with neurofibrillary tangle-containing neurons in Alzheimer disease. In vitro and in vivo experimental work has shown reciprocal induction between alpha-synuclein and injured neurons on one hand and activated microglia and cytokine overexpression on the other. These neuroinflammatory processes may be a common link driving progression in both diseases and explaining the frequent overlap between the 2 diseases.
    Journal of Neuropathology and Experimental Neurology 09/2007; 66(8):683-6. · 4.35 Impact Factor
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    ABSTRACT: Medulloblastoma (MB) is the most common malignant brain tumor of childhood. Although modern therapy has produced five-year survival rates as high as 70% for some MB patients, this resulted in significant long-term treatment-related morbidity. The cellular mechanisms involved in metastatic spread of medulloblastoma are largely unknown. Neurotrophins (NT) comprise a family of structurally and functionally related neurotrophic factors that are critical for central nervous system (CNS) development with nerve growth factor (NGF) being the prototypic NT. NT acts through two groups of structurally unrelated neurotrophin receptors (NTR): a family of receptor tyrosine kinases (Trks, mainly TrkA, TrkB, and TrkC) and a tumor necrosis factor receptor (TNFR)-like molecule called p75NTR TrkC expression is a good prognostic indicator for MB. TrkC binds only to neurotrophin-3 (NT-3) whereas p75 binds to all NT family members. Importantly, little is known about the biological functions of p75 in primitive neuroectodermal tumors such as MB. In contrast, NT-regulated heparanase (HPSE) is a unique extracellular matrix-degrading enzyme known to be associated with tumor progression in a wide variety of cancers. However, HPSE roles in MB invasive pathways have not been investigated. We provide evidence of a differential expression of HPSE in newly-developed medulloblastoma cell lines. Secondly, we show a correlation between HPSE expression and the invasive properties of these medulloblastoma lines. Thirdly, by performing investigations to elucidate prognostic implications of HPSE and TrkC/p75NTR expression in MB, we demonstrate a correlation between p75NTR and HPSE expression. Finally, by using antibodies specific to TrkC and immunohistochemistry (IHC) we prove that IHC scores reveal a significant expression of HPSE in 76% of MB tissues from children aged 3 years and older. Taken together, our data provide evidence that HPSE functionality, in a context linked to TrkC and p75NTR activation, may play critical roles in medulloblastoma tumor invasion and progression.
    Journal of experimental & clinical cancer research: CR 04/2007; 26(1):5-23. · 1.50 Impact Factor

Publication Stats

6k Citations
463.83 Total Impact Points

Institutions

  • 2007–2013
    • University of Toledo
      • Department of Pathology
      Toledo, Ohio, United States
  • 1994–2013
    • University of Arkansas at Little Rock
      Little Rock, Arkansas, United States
  • 2010
    • Medical University of Ohio at Toledo
      Toledo, Ohio, United States
  • 1993–2009
    • University of Arkansas for Medical Sciences
      • • Department of Neurology
      • • Department of Anesthesiology
      Little Rock, Arkansas, United States
  • 2008
    • Central Arkansas Veterans Healthcare System
      Washington, Washington, D.C., United States
  • 1994–2008
    • Second Military Medical University, Shanghai
      Shanghai, Shanghai Shi, China
  • 2004
    • University of Florida
      • Department of Neuroscience
      Gainesville, FL, United States
  • 2000
    • Banner Sun Health Research Institute
      Sun City, Arizona, United States
  • 1999
    • Hinchingbrooke Health Care NHS Trust
      Huntingdon, England, United Kingdom
    • University of Glasgow
      Glasgow, Scotland, United Kingdom
  • 1993–1999
    • Arkansas Children's Hospital
      Little Rock, Arkansas, United States
  • 1997–1998
    • U.S. Department of Veterans Affairs
      Washington, Washington, D.C., United States