Amyloid beta (Aβ) plaques are one of the hallmarks of Alzheimer's disease (AD). However, currently available anti-amyloid therapies fail to show effectiveness in the treatment of AD in humans. It has been found that there are different types of Aβ plaque (diffuse and focal types) in the postmortem human brain. In this study, we aimed to investigate the correlations among different types of Aβ plaque and AD-related neuropathological and cognitive changes based on a postmortem human brain bank in China. The results indicated that focal plaques, but not diffuse plaques, significantly increased with age in the human hippocampus. We also found that the number of focal plaques was positively correlated with the severity of AD-related neuropathological changes (measured by the "ABC" scoring system) and cognitive decline (measured by the Everyday Cognitive Insider Questionnaire). Furthermore, most of the focal plaques were co-localized with neuritic plaques (identified by Bielschowsky silver staining) and accompanied by microglial and other inflammatory cells. Our findings suggest the potential of using focal-type but not general Aβ plaques as biomarkers for the neuropathological evaluation of AD.
Alzheimer Disease/pathology* ; Amyloid beta-Peptides/metabolism* ; Amyloid beta-Protein Precursor ; Brain/pathology* ; Cognitive Dysfunction/pathology* ; Hippocampus/metabolism* ; Humans ; Neuroinflammatory Diseases ; Plaque, Amyloid/pathology*

Amyloid ; metabolism ; Humans ; Male ; Middle Aged ; Pituitary Neoplasms ; metabolism ; pathology ; surgery ; Plaque, Amyloid ; pathology ; Prolactin ; secretion ; Prolactinoma ; metabolism ; pathology ; surgery ; Synaptophysin ; metabolism

Adequate assessment of plaque deposition levels in the brain of mouse models of Alzheimer disease (AD) is required in many core issues of studies on AD, including studies on the mechanisms underlying plaque pathogenesis, identification of cellular factors modifying plaque pathology, and developments of anti-AD drugs. The present study was undertaken to quantitatively evaluate plaque deposition patterns in the brains of the two popular AD models, Tg2576 and Tg-APPswe/PS1dE9 mice. Coronally-cut brain sections of Tg2576 and Tg-APPswe/PS1dE9 mice were prepared and plaque depositions were visualized by staining with anti-amyloid beta peptides antibody. Microscopic images of plaque depositions in the prefrontal cortex, parietal cortex, piriform cortex and hippocampus were obtained and the number of plaques in each region was determined by a computer-aided image analysis method. A series of optical images representing a gradual increase of plaque deposition levels were selected in the four different brain regions and were assigned in each with a numerical grade of 1-6, where +1 was lowest and +6, highest, so that plaques per unit in mm2 increased "sigmoidally" over the grading scales. Analyzing plaque depositions using the photographic plaque reference panels and a computer-aid image analysis method, it was demonstrated that the brains of Tg2576 mice started to accumulate predominantly small plaques, while the brains of Tg-APPswe/PS1dE9 mice deposited relatively large plaques.
Alzheimer Disease/genetics/*pathology ; Amyloid beta-Protein Precursor/genetics/metabolism ; Animals ; Disease Models, Animal ; Humans ; Mice ; Mice, Transgenic ; Plaque, Amyloid/*pathology

Alzheimer's disease (AD) is a common disease in elder people. Its incidence rate is about 5% in people above 60 years old. It has become an important factor that seriously impacts the development of families and society, and caused wildly attention all over the world. In this article, we discuss the mechanisms of AD in four aspects and put forward the strategies of drug therapy.
Aged ; Alzheimer Disease ; drug therapy ; etiology ; Amyloid beta-Peptides ; metabolism ; Amyloid beta-Protein Precursor ; metabolism ; Apoptosis ; drug effects ; Cholinesterase Inhibitors ; therapeutic use ; Female ; Humans ; Male ; Nerve Growth Factor ; metabolism ; Neurofibrils ; pathology ; Nootropic Agents ; therapeutic use ; Plaque, Amyloid ; metabolism ; Synapses ; pathology

Small ubiquitin-related modifiers (SUMOs) belong to an important class of ubiquitin like proteins. SUMOylation is a post-translational modification process that regulates the functional properties of many proteins, among which are several proteins implicated in neurodegenerative diseases. This study was aimed to investigate the changes of SUMO-1 expression and modification, and the relationship between SUMO-1 and Alzheimer's disease (AD) pathology in APP/PS1 transgenic AD mice. Using Western blot, co-immunoprecipitation and immunofluorescent staining methods, the SUMO-1 expression and modification and its relation to tau, amyloid precursor protein (APP) and β-amyloid protein (Aβ) in the 12-month-old APP/PS1 transgenic AD mice were analyzed. The results showed that: (1) Compared with the normal wild-type mice, the expression and modification of SUMO-1 increased in brain of AD mice, which was accompanied by an increase of ubiquitination; (2) In RIPA soluble protein fraction of cerebral cortex, co-immunoprecipitation analysis showed tau SUMOylated by SUMO-1 increased in AD mice, however, AT8 antibody labeled phosphorylated tau was less SUMOylated whereas PS422 antibody labeled phosphorylated tau was similar to control mice; (3) Double immunofluorescent staining showed that SUMO-1 could distributed in amyloid plaques, appearing that some of SUMO-1 diffused in centre of some plaques and some of SUMO-1 co-localized with AT8 labeled phosphorylated tau forming punctate aggregates around amyloid plaques which was concerned as dystrophic neurites, however, less Aβ, APP and PS422 labeled phosphorylated tau were found co-localized with SUMO-1. These results suggest that SUMO-1 expression and modification increase abnormally in transgenic AD mice, which may participate in modulation of the formation of senile plaques and dystrophic neurites.
Alzheimer Disease ; physiopathology ; Amyloid beta-Peptides ; metabolism ; Amyloid beta-Protein Precursor ; metabolism ; Animals ; Brain ; pathology ; Mice ; Mice, Transgenic ; Neurites ; pathology ; Phosphorylation ; Plaque, Amyloid ; physiopathology ; SUMO-1 Protein ; metabolism ; Sumoylation ; tau Proteins ; metabolism

OBJECTIVETo study the association between Alzheimer' s disease (AD) and apolipoprotein E (apoE) polymorphism and apoE epsilon4 allele; and to investigate the role of apoE in senile plaque formation.

METHODSDuring the period from 1982 to 2003, 27 portmortem cases of AD from the archival files of Department of Pathology of Beijing Hospital, diagnosed according to the consortium to establish a registry for Alzheimer's disease (CERAD) criteria, were enrolled into this study. Among the 27 cases studied, there were 23 cases of definite AD and 4 cases of probable AD. Postmortem brain tissues from 67 neurologically unremarkable deceased were used as age-matched controls. Immunohistochemical study for beta-amyloid (Abeta) and Tau protein, as well as immunohistochemical study for Abeta/apoE, were performed in all AD cases using streptavidin-peroxidase (SP) and double immunostaining ( SP/ABC) methods, respectively. Senile plaques and neurofibrillary tangles in the 23 cases of definite AD were further quantified. The apoE genotypes in all cases were analyzed by polymerase chain reaction and restriction fragment length polymorphism technologies.

RESULTSImmunohistochemical study for Abeta distinguished 4 different types of senile plaques: diffuse non-neuritic plaques, diffuse neuritic plaques, dense-core neuritic plaques and dense-core non-neuritic plaques. Double immunohistochemistry for Abeta/apoE showed that some senile plaques were positive for both Abeta and apoE. The expression rates for Abeta and apoE in these 4 different types of senile plaques were 4. 28%, 84. 71%, 8.50% and 2.51%, respectively. The positivity rate for Abeta/apoE in diffuse neuritic plaques were significantly higher than those in other 3 types (P < 0.01). The frequency of occurrence of apoE epsilon4 allele in AD was significantly higher than that in the control group (P < 0.01). The numbers of senile plaques and neurofibrillary tangles in AD cases with apoE epsilon4 allele were also significantly higher than those in AD cases without apoE epsilon4 allele (P < 0.01).

CONCLUSIONSApoE polymorphism is associated with AD. The presence of apoE epsilon4 allele carries a higher risk for the development of AD. ApoE may also play an important role in the transformation of diffuse non-neuritic plaques to diffuse neuritic plaques.

Aged ; Aged, 80 and over ; Alleles ; Alzheimer Disease ; metabolism ; pathology ; Amyloid beta-Peptides ; metabolism ; Apolipoproteins E ; genetics ; metabolism ; Brain ; metabolism ; pathology ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Neurofibrillary Tangles ; pathology ; Plaque, Amyloid ; pathology ; tau Proteins ; metabolism

OBJECTIVETo recognize relationship of protein related neurodegeneration abnormal aggregation in the aged brains with their cognitive and motor functions.

METHODSBrain tissues from the consecutive autopsy cases of the aged from January 2005 to December 2006 in PLA General Hospital were carried out for immunohistochemical staining with beta amyloid, tau, α-synuclein and ubiquitin antibodies. The consortium to establish a registry for Alzheimer's disease (CERAD) was used to semi-quantitatively analyze Aβ positive core plaques density and Braak staging for tau positive neurofibrillary tangles (NFTs) and α-synuclein positive Lewy bodies. In addition, Aβ positive cerebral amyloid angiopathy (CAA), neuritic plaques and various ubiquitin positive structures were also observed. The relationship of these protein abnormal depositions in the aged brains with cognitive and motor functions were analyzed.

RESULTSIn brain tissues of 16 consecutive autopsy cases of the aged from 78 to 95 years, there were 13 cases with Aβ positive core plaques, their density was 2 cases with sparse, 2 cases with moderate and 9 cases with frequent, respectively, according to CREAD.Eight cases with Aβ positive CAA were found, including 6 cases of mild CAA and 2 cases of severe CAA. There were 12 cases with tau positive NFTs, including 6 cases with Braak stageI-II, 4 cases with stage III-IV and 2 cases with stage V-VI. There were 5 cases with frequent Aβ core plaques, meanwhile existing numerous tau/ubiquitin positive neuritic plaques and Braak stage IV-VI of tau positive NFTs, all of them presented cognitive dysfunction. Among 4 other cases with frequent Aβ core plaques, only one case coexisted α-synuclein positive Lewy bodies showed moderate cognitive impairment, remaining 3 cases did not present cognitive dysfunction. There were 4 cases with α-synuclein positive Lewy bodies in the brainstem, and all of these cases presented parkinsonian motor dysfunction. 13 cases with ubiquitin positive structures were found.

CONCLUSIONSBeta amyloid protein positive deposit in the aged brain is an important marker of normal brain aging and cognitive impairment; frequent Aβ core plaques in the neocortex plus Braak IV and above tau positive NFTs are closely related to cognitive dysfunction of Alzheimer's disease; α-synuclein positive Lewy bodies in the brainstem is one of the important pathological markers of parkinsonian motor disorders; ubiquitin deposition involves the development of some characteristic structures of several neurodegenerative diseases.

Aged ; Alzheimer Disease ; metabolism ; pathology ; Amyloid beta-Peptides ; analysis ; Autopsy ; Brain ; pathology ; Brain Chemistry ; Cerebral Amyloid Angiopathy ; Humans ; Neurofibrillary Tangles ; chemistry ; pathology ; Plaque, Amyloid ; Ubiquitin ; analysis ; alpha-Synuclein ; analysis ; tau Proteins ; analysis

The plant viral protease, NIa, has a strict substrate specificity for the consensus sequence of Val-Xaa-His-Gln, with a scissoring property after Gln. We recently reported that NIa efficiently cleaved the amyloid-beta (Abeta) peptide, which contains the sequence Val-His-His-Gln in the vicinity of the cleavage site by alpha-secretase, and that the expression of NIa using a lentiviral system in the brain of AD mouse model reduced plaque deposition levels. In the present study, we investigated whether exogenous expression of NIa in the brain of AD mouse model is beneficial to the improvement of cognitive deficits. To address this question, Lenti-NIa was intracerebrally injected into the brain of Tg-APPswe/PS1dE9 (Tg-APP/PS1) mice at 7 months of age and behavioral tests were performed 15-30 days afterwards. The results of the water maze test indicated that Tg-APP/PS1 mice which had been injected with Lenti-GFP showed an increased latency in finding the hidden-platform and markedly enhanced navigation near the maze-wall, and that such behavioral deficits were significantly reversed in Tg-APP/PS1 mice injected with Lenti-NIa. In the passive avoidance test, Tg-APP/PS1 mice exhibited a severe deficit in their contextual memory retention, which was reversed by NIa expression. In the marble burying test, Tg-APP/PS1 mice buried marbles fewer than non-transgenic mice, which was also significantly improved by NIa. After behavioral tests, it was verified that the Tg-APP/PS1 mice with Lenti-NIa injection had reduced Abeta levels and plaque deposition when compared to Tg-APP/PS1 mice. These results showed that the plant viral protease, NIa, not only reduces Abeta pathology, but also improves behavioral deficits.
Alzheimer Disease/*metabolism/pathology/physiopathology ; Amyloid beta-Peptides/*metabolism ; Amyloid beta-Protein Precursor/genetics ; Animals ; Avoidance Learning ; Brain/*metabolism/pathology/physiopathology ; *Cognition ; Cognition Disorders ; Disease Models, Animal ; Endopeptidases/*genetics/metabolism ; Gene Expression ; Maze Learning ; Memory ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Plaque, Amyloid/metabolism/*pathology ; Presenilin-1/genetics ; Viral Proteins/*genetics/metabolism

OBJECTIVESTo investigate the changes of nuclear factor (NF-)κBp65 and inflammatory chemotactic factors including monocyte chemoattractant protein 1 (MCP-1/CCL-2), macrophage inflammatory protein 1α (MIP-1α/CCL-3), glial fibrillary acidic protein (GFAP) in brains of the patients with Alzheimer's disease (AD) and reveal the correlation of these factors.

METHODSTen patients with AD and 8 age-matched control subjects were selected in the study. Immunohistochemistry was performed to determine the protein expression of NF-κBp65, MCP-1, MIP-1α and GFAP. Double-immunohistochemistry was used to detect the expression of GFAP and β-amyloid peptide 1-42 (Aβ(1-42)) in the hippocampus, temporal and frontal cortices.

RESULTSAs compared to age-matched controls (the numbers of the positively stained neuronal cells: 0.31 ± 0.20, 0.25 ± 0.20 and 0.25 ± 0.20, respectively), the immunoreactivities of NF-κBp65 in the hippocampus and the temporal and frontal cortices (numbers of the positively stained cells: 3.6 ± 1.5, 2.2 ± 1.2 and 2.2 ± 1.2, respectively) were significantly increased in AD brains. The levels of MCP-1 and MIP-1α in the hippocampus, and the temporal and frontal cortices (numbers of the positively stained neuronal cells: 8.0 ± 1.3, 8.8 ± 1.0, 9.3 ± 1.4, respectively;and 8.1 ± 1.5, 12.5 ± 1.1, 6.4 ± 1.1, respectively) with AD were significantly higher than those of controls (the numbers of the positive neuronal cells: 4.5 ± 0.9, 4.5 ± 0.6, 4.0 ± 1.8, respectively; and 5.0 ± 1.9, 6.3 ± 2.2, 3.8 ± 1.5, respectively). An increased number of glial cells stained with GFAP were observed to extensively distribute around the senile plaques in AD brains. There were significant correlations between NF-κBp65 and these inflammatory chemotactic factors in AD brains.

CONCLUSIONCorrelative expressions of NF and inflammatory chemotactic factors were found in the brains of AD patients, through a mechanism that may involve the inflammatory response induced by Aβ in the processing of AD.

Aged ; Aged, 80 and over ; Alzheimer Disease ; metabolism ; pathology ; Brain ; metabolism ; pathology ; Chemokine CCL2 ; metabolism ; Chemokine CCL3 ; metabolism ; Female ; Frontal Lobe ; metabolism ; pathology ; Glial Fibrillary Acidic Protein ; metabolism ; Hippocampus ; metabolism ; pathology ; Humans ; Immunohistochemistry ; Male ; Neuroglia ; metabolism ; pathology ; Plaque, Amyloid ; metabolism ; pathology ; Temporal Lobe ; metabolism ; pathology ; Transcription Factor RelA ; metabolism

The possibility that P2X7 receptor (P2X7R) expression in microglia would mediate neuronal damage via reactive oxygen species (ROS) production was examined in the APPswe/PS1dE9 mouse model of Alzheimer's disease (AD). P2X7R was predominantly expressed in CD11b-immunopositive microglia from 3 months of age before Abeta plaque formation. In addition, gp91phox, a catalytic subunit of NADPH oxidase, and ethidium fluorescence were detected in P2X7R-positive microglial cells of animals at 6 months of age, indicating that P2X7R-positive microglia could produce ROS. Postsynaptic density 95-positive dendrites showed significant damage in regions positive for P2X7R in the cerebral cortex of 6 month-old mice. Taken together, up-regulation of P2X7R activation and ROS production in microglia are parallel with Abeta increase and correlate with synaptotoxicity in AD.
Aging ; *Alzheimer Disease/genetics/metabolism/pathology ; Amyloid beta-Peptides ; Animals ; Antigens, CD11b/immunology ; Blotting, Western ; Cerebral Cortex/metabolism/*pathology ; Disease Models, Animal ; Gene Expression ; Mice ; Mice, Transgenic ; Microglia/*metabolism/pathology ; Neurons/metabolism/*pathology ; Plaque, Amyloid ; Reactive Oxygen Species/*metabolism ; Receptors, Immunologic/analysis ; Receptors, Purinergic P2X7/*genetics/metabolism