Author
John Q. Trojanowski
Other affiliations: Vanderbilt University, University of California, San Francisco, University of Michigan ...read more
Bio: John Q. Trojanowski is an academic researcher from University of Pennsylvania. The author has contributed to research in topics: Alzheimer's disease & Dementia. The author has an hindex of 226, co-authored 1467 publications receiving 213948 citations. Previous affiliations of John Q. Trojanowski include Vanderbilt University & University of California, San Francisco.
Papers published on a yearly basis
Papers
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TL;DR: Six broad areas of neuropathological investigation into schizophrenia are summarized and discussed and a general lack of neurodegenerative disease lesions or ongoing astrocytosis that would indicate post-maturational neural injury is found.
Abstract: The search for the defining neuropathology of schizophrenia continues to be one of the highest priority areas of research into this severely debilitating and common neuropsychiatric disorder. While lesions that are diagnostic of the disorder have not yet been identified, recent efforts employing molecule-specific probes and quantitative methods of analysis have enumerated many potentially important findings in the brains of patients with schizophrenia that warrant confirmation and elucidation. In this review, the major findings of six broad areas of neuropathological investigation are summarized and discussed. While substantial controversy exists in all areas, in sum: (1) diagnostic neuropathological investigations find only assorted and nonspecific abnormalities in the brains of schizophrenics that are likely to be representative of lesions found in age-compatible control groups; (2) morphometric studies of gross structures generally confirm the clinical in vivo neuroimaging findings of enlarged ventricles, decreased size of ventromedial temporal lobe structures, and decreased parahippocampal cortical thickness; (3) morphometric microscopy studies find frequent alterations in neuron density and decreased neuron size in limbic, temporal, and frontal regions; (4) investigations of connectivity are at an early stage but describe abnormal dendritic spine densities in the cortex, various changes in synaptic vesicle protein expression in limbic, temporal, and frontal cortices, and alterations in glutamatergic, catecholaminergic, and intrinsic innervation in anterior cingulate cortex – together, these findings suggest a “miswiring” in the schizophrenic brain; (5) investigations of aberrant neurodevelopment in schizophrenia describe abnormalities in cortical cytoarchitecture and several developmentally regulated proteins in the hippocampal region suggesting abnormal neuronal migration, differentiation, and/or cell pruning; and (6) studies of neurodegeneration and neural injury find a general lack of neurodegenerative disease lesions or ongoing astrocytosis that would indicate post-maturational neural injury.
211 citations
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TL;DR: The glucocerebrosidase gene was examined in 75 autopsy specimens with different synucleinopathies and identified mutations in 23% of cases of dementia with Lewy bodies, expanding on previous findings in subjects with Parkinson disease.
Abstract: The synucleinopathies are neurodegenerative disorders defined by inclusions composed of aberrantly fibrillized α-synuclein, but factors contributing to this process remain largely unknown. The authors examined the glucocerebrosidase gene in 75 autopsy specimens with different synucleinopathies and identified mutations in 23% of cases of dementia with Lewy bodies, expanding on previous findings in subjects with Parkinson disease. Mutations in this lysosomal protein may interfere with the clearance or promote aggregation of α-synuclein.
210 citations
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TL;DR: It is demonstrated that cerebrospinal fluid neurogranin is increased already at the early clinical stage of Alzheimer's disease and predicts cognitive deterioration and disease-associated changes in metabolic and structural biomarkers over time.
Abstract: Synaptic dysfunction is linked to cognitive symptoms in Alzheimer's disease. Thus, measurement of synapse proteins in cerebrospinal fluid may be useful biomarkers to monitor synaptic degeneration. Cerebrospinal fluid levels of the postsynaptic protein neurogranin are increased in Alzheimer's disease, including in the predementia stage of the disease. Here, we tested the performance of cerebrospinal fluid neurogranin to predict cognitive decline and brain injury in the Alzheimer's Disease Neuroimaging Initiative study. An in-house immunoassay was used to analyse neurogranin in cerebrospinal fluid samples from a cohort of patients who at recruitment were diagnosed as having Alzheimer's disease with dementia (n = 95) or mild cognitive impairment (n = 173), as well as in cognitively normal subjects (n = 110). Patients with mild cognitive impairment were grouped into those that remained cognitively stable for at least 2 years (stable mild cognitive impairment) and those who progressed to Alzheimer's disease dementia during follow-up (progressive mild cognitive impairment). Correlations were tested between baseline cerebrospinal fluid neurogranin levels and baseline and longitudinal cognitive impairment, brain atrophy and glucose metabolism within each diagnostic group. Cerebrospinal fluid neurogranin was increased in patients with Alzheimer's disease dementia (P < 0.001), progressive mild cognitive impairment (P < 0.001) and stable mild cognitive impairment (P < 0.05) compared with controls, and in Alzheimer's disease dementia (P < 0.01) and progressive mild cognitive impairment (P < 0.05) compared with stable mild cognitive impairment. In the mild cognitive impairment group, high baseline cerebrospinal fluid neurogranin levels predicted cognitive decline as reflected by decreased Mini-Mental State Examination (P < 0.001) and increased Alzheimer's Disease Assessment Scale-cognitive subscale (P < 0.001) scores at clinical follow-up. In addition, high baseline cerebrospinal fluid neurogranin levels in the mild cognitive impairment group correlated with longitudinal reductions in cortical glucose metabolism (P < 0.001) and hippocampal volume (P < 0.001) at clinical follow-up. Furthermore, within the progressive mild cognitive impairment group, elevated cerebrospinal fluid neurogranin levels were associated with accelerated deterioration in Alzheimer's Disease Assessment Scale-cognitive subscale (β = 0.0017, P = 0.01). These data demonstrate that cerebrospinal fluid neurogranin is increased already at the early clinical stage of Alzheimer's disease and predicts cognitive deterioration and disease-associated changes in metabolic and structural biomarkers over time.
210 citations
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TL;DR: Comparison of tau pathologies in DP with those in AD showed that the same tau epitopes map to filamentous tau inclusions in AD and DP brains, while the abnormal tau proteins isolated from DP brains are indistinguishable from the six abnormally phosphorylated brain tau isoforms in AD brains, suggesting recurrent TBI may cause dementia pugilistica by activating pathological mechanisms similar to those involved in AD.
Abstract: Insights into mechanisms of familial Alzheimer's disease (AD) caused by genetic mutations have emerged rapidly compared to sporadic AD. Indeed, despite identification of several sporadic AD risk factors, it remains enigmatic how or why they predispose to neurodegenerative disease. For example, traumatic brain injury (TBI) predisposes to AD, and recurrent TBI in career boxers may cause a progressive memory disorder associated with AD-like brain pathology known as dementia pugilistica (DP). Although the reasons for this are unknown, repeated TBI may cause DP by mechanisms similar to those involved in AD. To investigate this possibility, we compared the molecular profile of tau pathologies in DP with those in AD and showed that the same tau epitopes map to filamentous tau inclusions in AD and DP brains, while the abnormal tau proteins isolated from DP brains are indistinguishable from the six abnormally phosphorylated brain tau isoforms in AD brains. Thus, these data suggest that recurrent TBI may cause DP by activating pathological mechanisms similar to those that cause brain degeneration due to accumulations of filamentous tau lesions in AD, and similar, albeit attenuated, activation of these processes by a single TBI may increase susceptibility to sporadic AD decades after the event.
209 citations
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TL;DR: In this paper, the authors investigated the protein levels and activity of 12/15-LOX in different brain regions of histopathologically confirmed Alzheimer's disease and control cases, using quantitative Western blot analysis.
Abstract: Alzheimer’s disease (AD) is a chronic neurodegenerative disorder that impairs cognition and behavior. Although the initiating molecular events are not known, increasing evidence suggests that oxidative stress could play a functional role in its pathogenesis. Lipoxygenase (LOX) enzymes by oxidizing polyunsaturated fatty acids synthesize hydroperoxyacids, which are potent pro-oxidant mediators. Because circumstantial evidence suggests that 12/15-LOX is a major source of oxidative stress, we investigated the protein levels and activity of this enzyme in different brain regions of histopathologically confirmed AD and control cases. Using quantitative Western blot analysis we demonstrated that in affected frontal and temporal regions of AD brains the amount of 12/15-LOX was higher compared with controls, whereas no difference between the two groups was detected in the cerebellum. This observation was confirmed by immunohistochemical studies. Levels of 12/15-hydroxyeicosatetraenoic acids, metabolic products of 12/15-LOX, were also markedly elevated in AD brains compared to controls. This increase directly correlated with brain lipid peroxidation, and inversely with vitamin E levels. Finally, genetic deletion of this enzyme in vitro resulted in a reduction of the cellular oxidative stress response after incubation with H2O2 or amyloid β. These data show that the 12/15-LOX metabolic pathway is increased and correlates with an oxidative imbalance in the AD brain, implying that this enzyme might contribute to the pathogenesis of this neurodegenerative disorder.
208 citations
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28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。
18,940 citations
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Johns Hopkins University1, Johns Hopkins University School of Medicine2, Mayo Clinic3, McGill University4, Harvard University5, University of California, Irvine6, University of Pittsburgh7, Columbia University Medical Center8, Eli Lilly and Company9, Washington University in St. Louis10, UCL Institute of Neurology11, VU University Medical Center12, Alzheimer's Association13, Northwestern University14, National Institutes of Health15
TL;DR: The workgroup sought to ensure that the revised criteria would be flexible enough to be used by both general healthcare providers without access to neuropsychological testing, advanced imaging, and cerebrospinal fluid measures, and specialized investigators involved in research or in clinical trial studies who would have these tools available.
Abstract: The National Institute on Aging and the Alzheimer's Association charged a workgroup with the task of revising the 1984 criteria for Alzheimer's disease (AD) dementia. The workgroup sought to ensure that the revised criteria would be flexible enough to be used by both general healthcare providers without access to neuropsychological testing, advanced imaging, and cerebrospinal fluid measures, and specialized investigators involved in research or in clinical trial studies who would have these tools available. We present criteria for all-cause dementia and for AD dementia. We retained the general framework of probable AD dementia from the 1984 criteria. On the basis of the past 27 years of experience, we made several changes in the clinical criteria for the diagnosis. We also retained the term possible AD dementia, but redefined it in a manner more focused than before. Biomarker evidence was also integrated into the diagnostic formulations for probable and possible AD dementia for use in research settings. The core clinical criteria for AD dementia will continue to be the cornerstone of the diagnosis in clinical practice, but biomarker evidence is expected to enhance the pathophysiological specificity of the diagnosis of AD dementia. Much work lies ahead for validating the biomarker diagnosis of AD dementia.
13,710 citations
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TL;DR: It has been more than 10 years since it was first proposed that the neurodegeneration in Alzheimer's disease (AD) may be caused by deposition of amyloid β-peptide in plaques in brain tissue and the rest of the disease process is proposed to result from an imbalance between Aβ production and Aβ clearance.
Abstract: It has been more than 10 years since it was first proposed that the neurodegeneration in Alzheimer9s disease (AD) may be caused by deposition of amyloid β-peptide (Aβ) in plaques in brain tissue. According to the amyloid hypothesis, accumulation of Aβ in the brain is the primary influence driving AD pathogenesis. The rest of the disease process, including formation of neurofibrillary tangles containing tau protein, is proposed to result from an imbalance between Aβ production and Aβ clearance.
12,652 citations
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9,362 citations
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TL;DR: There is growing evidence that aging involves, in addition, progressive changes in free radical-mediated regulatory processes that result in altered gene expression.
Abstract: At high concentrations, free radicals and radical-derived, nonradical reactive species are hazardous for living organisms and damage all major cellular constituents. At moderate concentrations, how...
9,131 citations