Alva G.,ATP Clinical Research |
Schmitt F.A.,Sanders Brown Center on Aging |
Meng X.,Novartis |
International Journal of Geriatric Psychiatry | Year: 2011
Objective: In Alzheimer's disease (AD), rivastigmine has demonstrated statistically significant efficacy versus placebo on cognition and activities of daily living (ADL). The aim of this retrospective analysis was to further evaluate the treatment effects of rivastigmine on individual ADL items. Methods: This exploratory analysis focused on the Alzheimer's Disease Cooperative Study Activities of Daily Living (ADCS-ADL) outcome from a large, international, 24-week, controlled trial of rivastigmine once-daily transdermal patch and twice-daily capsules in AD (CENA713D2320, NCT00099242). Percentages of patients "improving" or "not worsening" on individual ADL items were calculated and changes from baseline with rivastigmine versus placebo were evaluated. Results: Patients received rivastigmine patch (9.5 mg/24 h; n=247), capsule (12 mg/day; n=254), and placebo (n=281). Statistically significant changes from baseline in composite ADCS-ADL scores in both rivastigmine treatment groups versus placebo (p<0.05) had previously been reported. In this responder analysis of the subset of patients who showed baseline functional impairments on each item, statistically significant differences favoring rivastigmine were seen on the following functions: bathing, clearing dishes, obtaining a beverage, garbage disposal, traveling, shopping, writing, using household appliances, and talking about current events. A responder analysis of emergence of ADL impairment was not as sensitive to treatment effects. Conclusions: These findings suggest that rivastigmine may benefit specific ADL, particularly in patients who are already exhibiting functional impairment. Further research is required to improve understanding of how drugs such as rivastigmine exert their clinical effects. Copyright © 2010 John Wiley & Sons, Ltd.
Nelson P.T.,University of Kentucky |
Nelson P.T.,Sanders Brown Center on Aging |
Wang W.-X.,Sanders Brown Center on Aging |
Partch A.B.,University of Kentucky |
And 9 more authors.
Journal of Neuropathology and Experimental Neurology | Year: 2015
Hippocampal sclerosis of aging (HS-Aging) is a common high-morbidity neurodegenerative condition in elderly persons. To understand the risk factors for HS-Aging, we analyzed data from the Alzheimer's Disease Genetics Consortium and correlated the data with clinical and pathologic information from the National Alzheimer's Coordinating Center database. Overall, 268 research volunteers with HS-Aging and 2,957 controls were included; detailed neuropathologic data were available for all. The study focused on single-nucleotide polymorphisms previously associated with HS-Aging risk: rs5848 (GRN), rs1990622 (TMEM106B), and rs704180 (ABCC9). Analyses of a subsample that was not previously evaluated (51 HS-Aging cases and 561 controls) replicated the associations of previously identified HS-Aging risk alleles. To test for evidence of gene-gene interactions and genotype-phenotype relationships, pooled data were analyzed. The risk for HS-Aging diagnosis associated with these genetic polymorphisms was not secondary to an association with either Alzheimer disease or dementia with Lewy body neuropathologic changes. The presence of multiple risk genotypes was associated with a trend for additive risk for HS-Aging pathology. We conclude that multiple genes play important roles in HS-Aging, which is a distinctive neurodegenerative disease of aging. © 2014 by the American Association of Neuropathologists, Inc.
Schmitt F.A.,Sanders Brown Center on Aging |
Xiangyi Meng,Novartis |
Tekin S.,Novartis |
American Journal of Alzheimer's Disease and other Dementias | Year: 2010
Alzheimer's disease (AD) patients treated with rivastigmine transdermal patch have shown statistically significant differences versus placebo on the AD Assessment scale-cognitive subscale (ADAS-cog). In this retrospective analysis of a double-blind, placebo- and active-controlled, 24-week clinical trial, the specific effects of rivastigmine patch on individual ADAS-cog items and cognitive domains (memory, language, and praxis) were explored. The mean baseline to week 24 changes were calculated for each ADAS-cog item and domain in this exploratory, hypothesis-generating analysis. Patients on 9.5 mg/24 h rivastigmine patch, 17.4 mg/24 h rivastigmine patch, and 3 to 12 mg/d rivastigmine capsules showed improvements over placebo on the memory and praxis ADAS-cog subscales. The rivastigmine patch groups also showed improvements on the language subscale. Significant differences versus placebo were seen on several individual item scores in the rivastigmine-treated groups. Rivastigmine patch was associated with improvements on the memory, praxis, and language domains of cognition in patients with mild-to-moderate AD. © The Author(s) 2010.
PubMed | University of Massachusetts Boston, University of Kentucky and Sanders Brown Center on Aging
Type: Journal Article | Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience | Year: 2016
One of the most common symptoms of Alzheimers disease (AD) and related tauopathies is memory loss. The exact mechanisms leading to memory loss in tauopathies are not yet known; however, decreased translation due to ribosomal dysfunction has been implicated as a part of this process. Here we use a proteomics approach that incorporates subcellular fractionation and coimmunoprecipitation of tau from human AD and non-demented control brains to identify novel interactions between tau and the endoplasmic reticulum (ER). We show that ribosomes associate more closely with tau in AD than with tau in control brains, and that this abnormal association leads to a decrease in RNA translation. The aberrant tau-ribosome association also impaired synthesis of the synaptic protein PSD-95, suggesting that this phenomenon contributes to synaptic dysfunction. These findings provide novel information about tau-protein interactions in human brains, and they describe, for the first time, a dysfunctional consequence of tau-ribosome associations that directly alters protein synthesis. Significance statement: Despite the identification of abnormal tau-ribosomal interactions in tauopathies >25 years ago, the consequences of this association remained elusive until now. Here, we show that pathological tau associates closely with ribosomes in AD brains, and that this interaction impairs protein synthesis. The overall result is a stark reduction of nascent proteins, including those that participate in synaptic plasticity, which is crucial for learning and memory. These data mechanistically link a common pathologic sign, such as the appearance of pathological tau inside brain cells, with cognitive impairments evident in virtually all tauopathies.
Gleichmann M.,U.S. National Institute on Aging |
Zhang Y.,U.S. National Institute on Aging |
Wood W.H.,U.S. National Institute on Aging |
Becker K.G.,U.S. National Institute on Aging |
And 8 more authors.
Neurobiology of Aging | Year: 2012
Activity-dependent modulation of neuronal gene expression promotes neuronal survival and plasticity, and neuronal network activity is perturbed in aging and Alzheimer's disease (AD). Here we show that cerebral cortical neurons respond to chronic suppression of excitability by downregulating the expression of genes and their encoded proteins involved in inhibitory transmission (GABAergic and somatostatin) and Ca 2+ signaling; alterations in pathways involved in lipid metabolism and energy management are also features of silenced neuronal networks. A molecular fingerprint strikingly similar to that of diminished network activity occurs in the human brain during aging and in AD, and opposite changes occur in response to activation of N-methyl-D-aspartate (NMDA) and brain-derived neurotrophic factor (BDNF) receptors in cultured cortical neurons and in mice in response to an enriched environment or electroconvulsive shock. Our findings suggest that reduced inhibitory neurotransmission during aging and in AD may be the result of compensatory responses that, paradoxically, render the neurons vulnerable to Ca 2+-mediated degeneration. © 2012.
Cykowski M.D.,Houston Methodist Hospital |
Takei H.,Houston Methodist Hospital |
Van Eldik L.J.,Sanders Brown Center on Aging |
Schmitt F.A.,Sanders Brown Center on Aging |
And 4 more authors.
Journal of Neuropathology and Experimental Neurology | Year: 2016
Transactivating responsive sequence (TAR) DNA-binding protein 43-kDa (TDP-43) pathology has been described in various brain diseases, but the full anatomical distribution and clinical and biological implications of that pathology are incompletely characterized. Here, we describe TDP-43 neuropathology in the basal forebrain, hypothalamus, and adjacent nuclei in 98 individuals (mean age, 86 years; median final mini-mental state examination score, 27). On examination blinded to clinical and pathologic diagnoses, we identified TDP-43 pathology that most frequently involved the ventromedial basal forebrain in 19 individuals (19.4%). As expected, many of these brains had comorbid pathologies including those of Alzheimer disease (AD), Lewy body disease (LBD), and/or hippocampal sclerosis of aging (HS-Aging). The basal forebrain TDP-43 pathology was strongly associated with comorbid HS-Aging (odds ratio = 6.8, p = 0.001), whereas there was no significant association between basal forebrain TDP-43 pathology and either AD or LBD neuropathology. In this sample, there were some cases with apparent preclinical TDP-43 pathology in the basal forebrain that may indicate that this is an early affected area in HS-Aging. We conclude that TDP-43 pathology in the basal forebrain is strongly associated with HS-Aging. These results raise questions about a specific pathogenetic relationship between basal forebrain TDP-43 and non-HSAging comorbid diseases (AD and LBD). © 2016 American Association of Neuropathologists, Inc. All rights reserved.
Ivanchak N.,University of Kentucky |
Fletcher K.,University of Kentucky |
Jicha G.A.,University of Kentucky |
Jicha G.A.,Sanders Brown Center on Aging
Current Psychiatry Reports | Year: 2012
Attentional deficits are frequently seen in isolation as the presenting sign and symptom of neurodegenerative disease, manifest as mild cognitive impairment (MCI). Persistent ADHD in the geriatric population could well be misconstrued as MCI, leading to the incorrect assumption that such persons are succumbing to a neurodegenerative disease process. Alternatively, the molecular, neuroanatomic, or neurochemical abnormalities seen in ADHD may contribute to the development of de novo late life neurodegenerative disease. The present review examines the issue of causality vs confound regarding the association of ADHD with MCI, suggesting that both are tenable hypotheses. © Springer Science+Business Media, LLC 2012.
Bieging K.T.,Northwestern University |
Fish K.,Northwestern University |
Bondada S.,Sanders Brown Center on Aging |
Bondada S.,University of Kentucky |
Longnecker R.,Northwestern University
Blood | Year: 2011
The link between EBV infection and Burkitt lymphoma (BL) is strong, but the mechanism underlying that link has been elusive. We have developed a mouse model for EBV-associated BL in which LMP2A, an EBV latency protein, and MYC are expressed in B cells. Our model has demonstrated the ability of LMP2A to accelerate tumor onset, increase spleen size, and bypass p53 inactivation. Here we describe the results of total gene expression analysis of tumor and pretumor B cells from our transgenic mouse model. Although we see many phenotypic differences and changes in gene expression in pretumor B cells, the transcriptional profiles of tumor cells from LMP2A/λ-MYC and λ-MYC mice are strikingly similar, with fewer than 20 genes differentially expressed.We evaluated the functional significance of one of the most interesting differentially expressed genes, Egr1, and found that it was not required for acceleration of tumor onset by LMP2A. Our studies demonstrate the remarkable ability of LMP2A to affect the pretumor B-cell phenotype and tumorigenesis without substantially altering gene expression in tumor cells. © 2011 by The American Society of Hematology.
Neltner J.H.,University of Kentucky |
Abner E.L.,Sanders Brown Center on Aging |
Schmitt F.A.,Sanders Brown Center on Aging |
Denison S.K.,Sanders Brown Center on Aging |
And 3 more authors.
Journal of Neuropathology and Experimental Neurology | Year: 2012
Quantitative neuropathologic methods provide information that is important for both research and clinical applications. The technologic advancement of digital pathology and image analysis offers new solutions to enable valid quantification of pathologic severity that is reproducible between raters regardless of experience. Using an Aperio ScanScope XT and its accompanying image analysis software, we designed algorithms for quantitation of amyloid and tau pathologies on 65 amyloid (6F/3D antibody) and 48 phospho-tau (PHF-1)-immunostained sections of human temporal neocortex. Quantitative digital pathologic data were compared with manual pathology counts. There were excellent correlations between manually counted and digitally analyzed neuropathologic parameters (R = 0.56-0.72). Data were highly reproducible among 3 participants with varying degrees of expertise in neuropathology (intraclass correlation coefficient values, >0.910). Digital quantification also provided additional parameters, including average plaque area, which shows statistically significant differences when samples are stratified according to apolipoprotein E allele status (average plaque area, 380.9 Î1/2m in apolipoprotein E [Latin Small Letter Open E]4 carriers vs 274.4 m for noncarriers; p < 0.001). Thus, digital pathology offers a rigorous and reproducible method for quantifying Alzheimer disease neuropathologic changes and may provide additional insights into morphologic characteristics that were previously more challenging to assess because of technical limitations. © 2012 by the American Association of Neuropathologists, Inc.
Lim Y.-b.,Yonsei University |
Mays C.E.,Sanders Brown Center on Aging |
Mays C.E.,University of Kentucky |
Kim Y.,Sanders Brown Center on Aging |
And 5 more authors.
Biomaterials | Year: 2010
Branched polyamines are effective in inhibiting prions in a cationic surface charge density dependent manner. However, toxicity associated with branched polyamines, in general, often hampers the successful application of the compounds to treat prion diseases. Here, we report that constitutively maintained cationic properties in branched polyamines reduced the intrinsic toxicity of the compounds while retaining the anti-prion activities. In prion-infected neuroblastoma cells, quaternization of amines in polyethyleneimine (PEI) and polyamidoamine (PAMAM) dendrimers markedly increased the nontoxic concentration ranges of the compounds and still supported, albeit reduced, an appreciable level of anti-prion activity in clearing prions from the infected cells. Furthermore, quaternized PEI was able to degrade prions at acidic pH conditions and inhibit the in vitro prion propagation facilitated by conversion of the normal prion protein isoform to its misfolded counterpart, although such activities were decreased by quaternization. Quaternized PAMAM was least effective in degrading prions but efficiently inhibited prion conversion with the same efficacy as unmodified PAMAM. Our results suggest that quaternization represents an effective strategy for developing nontoxic branched polyamines with potent anti-prion activity. This study highlights the importance of polyamine structural control for developing polyamine-based anti-prion agents and understanding of an action mechanism of quaternized branched polyamines. © 2009 Elsevier Ltd. All rights reserved.