Herpes simplex virus type 1 DNA is present in specific regions of brain from aged people with and without senile dementia of the Alzheimer type.

We have investigated the possible involvement of viruses, specifically Herpes simplex virus type 1, in senile dementia of the Alzheimer type (SDAT). Using the highly sensitive polymerase chain reaction, we have detected the viral thymidine kinase gene in post-mortem brain from 14/21 cases of senile dementia of the Alzheimer type and 9/15 elderly normals. The temporal cortex and hippocampus were usually virus-positive; in contrast, the occipital cortex was virus-negative in 9/9 SDAT cases and 5/5 elderly normals. Temporal and frontal cortex from younger normals (five infants and five middle-aged) were negative. Thus, the presence of Herpes simplex virus type 1 DNA is a region-dependent feature of the aged brain.     

Latent herpes simplex virus type 1 in normal and Alzheimer's disease brains.

A viral aetiology has long been suspected for Alzheimer's disease (AD) but until now, techniques have not been sufficiently sensitive to provide clear evidence for or against the presence of any viral genome in AD brain. We have used the very highly sensitive method of polymerase chain reaction to look for herpes simplex virus type 1 (HSV1) DNA, specifically the viral thymidine kinase (TK) gene, in autopsy brain specimens. DNA-samples from HSV-infected and uninfected Vero cells have been examined concurrently to provide standard "HSV-positive" and "HSV-negative" samples, the latter guarding also against false positives caused by cross-contamination. To preclude false negatives, we have checked the presence of the human gene, hypoxanthine phosphoribosyl transferase. In all specimens from 8 AD patients and 6 normal individuals (temporal, frontal and hippocampal), we have found viral TK sequences. In contrast, in preliminary studies on lymphocytes from normals and AD patients, we did not find TK sequences. It is postulated that factors such as number or expression of viral genes and host susceptibility might be related to incidence of AD.     

Incidence and distribution of herpes simplex virus types 1 and 2 from genital lesions in college women.

During a 9-month period, 9,772 women were treated at the student health center's gynecology clinic. Herpes simplex virus was isolated from 30 of 57 patients clinically diagnosed as suffering from a herpetic or herpetic-like genial infection for a virological incidence rate of 0.31%. Using virus plaque diameter in chick embryo cells and heat stability of viral thymidine kinase, 37% of the isolates were classified as herpes simplex virus type 1 and 63% were classified as herpes simplex virus type 2.     

Association of variants within APOE, SORL1, RUNX1, BACE1 and ALDH18A1 with dementia in Alzheimer's disease in subjects with Down syndrome

Background: Down syndrome (DS) is caused by either complete or partial triplication of chromosome 21, affecting approximately 1/1000 live births, and it is widely accepted that individuals with DS are more likely to develop dementia of Alzheimer's disease (DAD) compared with the general population. Many studies have investigated genetic susceptibility to AD in the general population, resulting in a number of potential candidate genes that may influence the development of DAD. The majority of these variants, however, have not been investigated in subjects with DS. Aim: The aim of this study was to determine whether genetic variants previously associated with AD in the general population, were also associated with DAD in individuals with DS. Methods: Genotyping of 43 SNPs within 28 genes was undertaken in 187 individuals with Down syndrome with and without dementia of Alzheimer's disease, using the SNPlex platform. Results: Significant associations of SNPs in five genes with DAD in DS were found, namely APOE, SORL1, BACE1, RUNX1 and ALDH18A1. As expected, the most strongly associated SNP was the APOE ?4 rs429358 variant (HR = 2.47 [1.58, 3.87], p = 7.52 × 10⁻⁵), although variants within the more recently implicated SORL1 and RUNX1 genes were also strongly associated with DAD in DS (HR = 0.54 [0.37, 0.80], p = 0.002 and HR = 1.61 [1.15, 2.26], p = 0.006 respectively). Conclusions: Our study demonstrates that a number of variants previously associated with AD in the general population are also associated with DAD in DS. To enable us to determine whether these variants, as well as other more recently revealed AD susceptibility variants, truly contribute to the development of DAD in DS, further multi-centre collaborative studies comprising large number of individuals with DS are needed.     

Investigating the role of rare coding variability in Mendelian dementia genes (APP,PSEN1, PSEN2, GRN,MAPT, and PRNP) in late-onset Alzheimer's disease

The overlapping clinical and neuropathologic features between late-onset apparently sporadic Alzheimer's disease (LOAD), familial Alzheimer's disease (FAD), and other neurodegenerative dementias (frontotemporal dementia, corticobasal degeneration, progressive supranuclear palsy, and Creutzfeldt-Jakob disease) raise the question of whether shared genetic risk factors may explain the similar phenotype among these disparate disorders. To investigate this intriguing hypothesis, we analyzed rare coding variability in 6 Mendelian dementia genes (APP, PSEN1, PSEN2, GRN, MAPT, and PRNP), in 141 LOAD patients and 179 elderly controls, neuropathologically proven, from the UK. In our cohort, 14 LOAD cases (10%) and 11 controls (6%) carry at least 1 rare variant in the genes studied. We report a novel variant in PSEN1 (p.I168T) and a rare variant in PSEN2 (p.A237V), absent in controls and both likely pathogenic. Our findings support previous studies, suggesting that (1) rare coding variability in PSEN1 and PSEN2 may influence the susceptibility for LOAD and (2) GRN, MAPT, and PRNP are not major contributors to LOAD. Thus, genetic screening is pivotal for the clinical differential diagnosis of these neurodegenerative dementias.     

Gliovascular alterations in sporadic and familial Alzheimer's disease: APOE3 Christchurch homozygote glioprotection

In response to brain insults, astrocytes become reactive, promoting protection and tissue repair. However, astroglial reactivity is typical of brain pathologies, including Alzheimer's disease (AD). Considering the heterogeneity of the reactive response, the role of astrocytes in the course of different forms of AD has been underestimated. Colombia has the largest human group known to have familial AD (FAD). This group carries the autosomal dominant and fully penetrant mutation E280A in PSEN1, which causes early-onset AD. Recently, our group identified an E280A carrier who did not develop FAD. The individual was homozygous for the Christchurch mutation R136S in APOE3 (APOEch). Remarkably, APOE is the main genetic risk factor for developing sporadic AD (SAD) and most of cerebral ApoE is produced by astroglia. Here, we characterized astrocyte properties related to reactivity, glutamate homeostasis, and structural integrity of the gliovascular unit (GVU), as factors that could underlie the pathogenesis or protection of AD. Specifically, through histological and 3D microscopy analyses of postmortem samples, we briefly describe the histopathology and cytoarchitecture of the frontal cortex of SAD, FAD, and APOEch, and demonstrate that, while astrodegeneration and vascular deterioration are prominent in SAD, FAD is characterized by hyperreactive-like glia, and APOEch displays the mildest astrocytic and vascular alterations despite having the highest burden of Aβ. Notably, astroglial, gliovascular, and vascular disturbances, as well as brain cell death, correlate with the specific astrocytic phenotypes identified in each condition. This study provides new insights into the potential relevance of the gliovasculature in the development and protection of AD. To our knowledge, this is the first study assessing the components of the GVU in human samples of SAD, FAD, and APOEch.     

Analysis of the herpes simplex virus type 1 UL6 gene in patients with stromal keratitis

Recent work suggests that herpes simplex virus (HSV) stromal keratitis in the mouse is caused by autoreactive T lymphocytes triggered by a 16 amino acid region of the HSV UL6 protein (aa299-314), Science 279, 1344-1347). In the present study we sought to determine whether genetic variation of this presumed autoreactive UL6 epitope is responsible for different pathogenic patterns of human HSV keratitis. To accomplish this, we sequenced the HSV UL6 gene from ocular isolates of 10 patients with necrotizing stromal keratitis, 7 patients with recurrent epithelial keratitis, and 8 patients with other forms of HSV keratitis. The sequences obtained predicted identical UL6(299-314) epitopes for all 25 viral isolates. Furthermore, the upstream sequence of all isolates was free of insertions, deletions, and stop codons. We conclude that different pathogenic patterns of human HSV keratitis occur independent of genetic variation of the HSV UL6 (299-314) epitope.     

Apoptosis and antigen receptor function in T and B cells following exposure to herpes simplex virus

T cells are an essential component of the immune response against herpes simplex virus (HSV) infection. We previously reported that incubation of T cells with HSV-infected fibroblasts inhibits subsequent T cell antigen receptor signal transduction. In the current study, we found that incubation of T cells with HSV-infected fibroblasts also leads to apoptosis in exposed T cells. Apoptosis was observed in Jurkat cells, a T cell leukemia line, and also in CD4(+) cells isolated from human peripheral blood mononuclear cells. Direct infection of these cells with HSV also resulted in apoptosis. Clinical isolates of both HSV type 1 and 2 induced apoptosis in infected T cells at comparable levels to cells infected with laboratory strains of HSV, suggesting an immune evasion mechanism that may be clinically relevant. Further understanding of these viral immune evasion mechanisms could be exploited for better management of HSV infection.     

Effects of S-acetylglutathione in cell and animal model of herpes simplex virus type 1 infection

Intracellular glutathione (GSH) plays an important regulatory role in the host response to viral infections. Replenishment of intracellular GSH is a desirable yet challenging goal, since systemic GSH supplementation is rather inefficient due to a short half-life of GSH in blood plasma. Further, GSH is not taken up by cells directly, but needs to be broken down into amino acids and resynthesized to GSH intracellularly, this process often being impaired during viral infections. These obstacles may be overcome by a novel glutathione derivative S-acetylglutathione (S-GSH), which is more stable in plasma and taken up directly by cells with subsequent conversion to GSH. In the present study, in vitro effects of supplementation with S-GSH or GSH on intracellular GSH levels, cell survival and replication of human herpes simplex virus type 1 (HSV-1) were studied in human foreskin fibroblasts. In addition, in vivo effects of supplementation with S-GSH or GSH on HSV-1-induced mortality were studied in hr/hr mice. In cell culture, viral infection resulted in a significant decrease of intracellular GSH levels. S-GSH efficiently and dose-dependently (5 and 10 mM tested) restored intracellular GSH, and this replenishment was more efficient than with GSH supplementation. In mice, S-GSH, but not GSH, significantly decreased HSV-1-induced mortality (P<0.05). The data suggest that S-GSH is a suitable antiviral agent against HSV-1 both in vitro and in vivo, indicating that this drug may be of benefit in the adjunctive therapy of HSV-1 infections.     

Cytotoxic T cells against herpes simplex virus in Behçet''s disease.

Lymphocytes from 36 patients with Behçet''s disease (20 in remission and 16 in active phase) were stimulated in vitro with herpes simplex virus and then tested for their ability to generate cytotoxic T cell responses to the virus. Significant cytotoxic responses were found. CD4+ and CD8+ subpopulations from the patients in remission generated specific cytotoxic activity against autologous target cells. These observations suggested that CD4+ and CD8+ cytotoxic T cells may have an important host response in herpes virus infection in Behçet''s disease.     

Generalized herpes simplex virus infection in an immunocompromised patient--report of a case and review of the literature

Patients with immunodeficiency or treatment-related immunosuppression are at an increased risk of developing severe herpes simplex virus (HSV) infection. We present a fatal case of a generalized HSV-1 infection in a 22-year-old female afflicted by acute lymphoblastic leukemia who was treated with polychemotherapy. The terminal clinical course was characterized by abdominal pain, progressive hepatic failure, and disseminated intravascular coagulation. Autopsy revealed non-perioral herpetic skin lesions and mucosal ulceration of the esophagus and colon. Punctuated areas of yellow-tan necrosis with hyperemic rims were detected in the liver, spleen, and lung. Numerous petechiae were observed on the mucosal surface of the esophagus, jejunum, ileum, and colon. Microscopically, lesions demonstrated the cellular changes characteristic of herpetic infection. Immunohistochemistry for identification of the virus using monoclonal antibodies against HSV-1 and HSV-2 showed positive staining for HSV-1. Polymerase chain reaction and sequencing confirmed HSV-1 positivity. Emphasis must be placed on clinical awareness of a generalized HSV infection in immunocompromised patients. Absence of orofacial or genital lesions does not rule out the possibility of active HSV infection.     

Analysis of varicella-zoster virus and herpes simplex virus in various clinical samples by the use of different PCR assays

Rapid and reliable detection of varicella-zoster virus (VZV) and herpes simplex virus type 1 (HSV-1) and -2 (HSV-2) is of clinical significance in immunocompromised patients and patients with infections of the central nervous system. This paper describes the detection of VZV and HSV using the commercially available Affigene^® VZV and Affigene^® HSV 1/2 tracer kits in comparison to “in-house” polymerase chain reaction (PCR) assays. For sample preparation, Qiagen (Hilden, Germany) and Affigene^® (Cepheid AB, Bromma, Sweden) DNA extraction kits were used. 175 samples were analyzed for VZV and 352 samples for HSV-1 and -2. Generally more positive results were obtained using the Affigene^® assays compared to the “in-house” methods independent of the DNA preparation method used. There were significant differences in sensitivity between the Affigene^® HSV 1/2 tracer and the “in-house” PCR assays for the detection of both HSV-1 and -2 in cerebrospinal fluid and vesicle/skin swabs. The Affigene^® HSV 1/2 and VZV tracers are very sensitive assays for detection of VZV and HSV. A wide variety of clinical samples can be examined in combination with either the Qiagen or the Affigene^® DNA extraction kits for preparation.     

Cognitive and neural signatures of the APOE E4 allele in mid-aged adults

The apolipoprotein E (APOE) e4 allele is strongly associated with increased risk of cognitive impairments in older adulthood. There is also a possible link to enhanced cognitive performance in younger adults, and the APOE e4 allele may constitute an example of antagonistic pleiotropy. The aim of this work was to investigate the cognitive and neural (functional) effects of the APOE e4 allele during mid-age (45–55 years), where a transition toward cognitive deficit might be expected. APOE e4 carriers (e4+) were compared with non-e4 carriers (e4−) on tasks of sustained and covert attention and prospective memory, and functional magnetic resonance imaging data acquired. Performance by e4+ was equivalent or better than e4− on all 3 tasks, although performance benefits were less pronounced than in youth. Neurally, e4+ showed less task-related recruitment of extrastriate and parietal areas. This became more evident when neural activation data were compared with that of young adults acquired in a parallel study. As expected, mid-age participants showed more diffuse neural activation. Notable was the fact that e4+ showed a relative inability to recruit parietal regions as they aged. This was coupled with a tendency to show greater recruitment of frontal regions, and underactivation of extrastriate visual regions. Thus, mid-age e4+ show a pattern of neural recruitment usually seen later in life, possibly reflecting the source of an accelerated aging profile that describes the e4 genotype.     

Dynamic SAP102 expression in the hippocampal subregions of rats and APP/PS1 mice of various ages

The hippocampus is a structurally and functionally complex brain area that plays important and diverse roles in higher brain functions, such as learning and memory, and mounting evidence indicates that different hippocampal subregions play distinctive roles. The hippocampus is also one of the first regions in the brain to suffer damage in Alzheimer's disease (AD). Synaptic dysfunction in the hippocampus, rather than neuronal loss per se, is paralleled by behavioural and functional deficits in AD. The membrane‐associated guanylate kinase (MAGUK) family of proteins, including SAP102, PSD‐95, PSD‐93 and SAP97, have long been recognized as essential components of the postsynaptic density (PSD) at excitatory synapses. Hippocampal spines are the predominant synaptic transmission sites of excitatory glutamatergic synapses. During postnatal brain development, individual MAGUK members show distinct expression patterns. Although SAP102 has been confirmed as the dominant scaffold protein in neonatal synapses, its expression profiles in adult and ageing rodent hippocampi are discrepant. Furthermore, in AD brains, significantly reduced SAP102 protein levels have been found, suggesting that SAP102 may be related to AD progression; however, the precise mechanism underlying this result remains unclear. Herein, we observed distinct SAP102 expression profiles in the hippocampal CA1, CA3 and DG subregions of rats and APPswe/PS1dE9 (APP/PS1) mice at various ages using immunofluorescence. In Wistar rats, SAP102 was not only highly expressed in the hippocampal subregions of neonatal rats but also maintained relatively high expression levels in adult hippocampi and displayed no obvious decreases in the CA1 and DG subregions of aged rats. Surprisingly, we observed abnormally high SAP102 expression levels in the CA1 stratum moleculare and CA3 stratum polymorphum subregions of 2‐month‐old APP/PS1 mice, but low SAP102 levels in the DG and CA3 subregions of 7‐month‐old APP/PS1 mice, reflecting the subregion‐specific reactivity and vulnerability of AD mouse models in different disease stages. Our findings provide fundamental data to support the functional differences of SAP102 in different hippocampal subregions during postnatal periods and may serve as the basis for additional functional studies on SAP102 in normal physiological conditions and different stages of AD.     

Lamotrigine attenuates deficits in synaptic plasticity and accumulation of amyloid plaques in APP/PS1 transgenic mice

Hyperactivity and its compensatory mechanisms may causally contribute to synaptic and cognitive deficits in Alzheimer's disease (AD). Blocking the overexcitation of the neural network, with levetiracetam (LEV), a sodium channel blocker applied in the treatment of epilepsy, prevented synaptic and cognitive deficits in human amyloid precursor protein (APP) transgenic mice. This study has brought the potential use of antiepileptic drugs (AEDs) in AD therapy. We showed that the chronic treatment with lamotrigine (LTG), a broad-spectrum AED, suppressed abnormal spike activity, prevented the loss of spines, synaptophysin immunoreactivity, and neurons, and thus attenuated the deficits in synaptic plasticity and learning and memory in APP and presenilin 1 (PS1) mice, which express human mutant APP and PS1. In contrast with LEV, which failed to reduce the generation of amyloid β, the chronic LTG treatment reduced the cleavage of APP by β-secretase and thus the numbers and the size of amyloid plaques in the brains of APP and PS1 mice. Moreover, the levels of brain-derived neurotrophic growth factor (BDNF) and nerve growth factor (NGF) were enhanced in the brains of APP and PS1 mice by the chronic LTG treatment. Therefore, these observations demonstrate that LTG attenuates AD pathology through multiple mechanisms, including modulation of abnormal network activity, reduction of the generation of amyloid beta and upregulation of BDNF and NGF.     

CSF beta-amyloid 1-42 and tau in Tunisian patients with Alzheimer's disease: the effect of APOE epsilon4 allele

Alzheimer's disease (AD) is the leading cause of dementia. Currently, no definitive diagnostic test for AD exists. An accurate, convenient and objective test to detect AD is urgently needed for efficient drug development and effective clinical use of emerging therapies. The aim of the present work is to investigate the usefulness of cerebrospinal fluid (CSF) beta-amyloid protein (Abeta1-42) and total tau protein (t-tau) analyses in the diagnosis of AD and whether apolipoprotein E (ApoE) epsilon4 allele is a factor for AD affecting Tunisian people. Abeta1-42 and t-tau levels were measured in CSF from AD patients (n=73), non-Alzheimer dementia (nAD, n=35) and healthy controls (HC, n=38) by sandwich enzyme-linked immunosorbent assay. Abeta1-42 levels were decreased and t-tau increased in AD patients. The combination of Abeta1-42 and t-tau at baseline yielded a sensitivity of 87.4% for detection of AD. The specificities were 97.3% for controls and 82.7% for other dementia. The ApoE epsilon4 allele frequency (29.5%) was significantly higher in the AD patients than in the nAD patients (17.1%) or in the control groups (9.5%). AD patients carrying ApoE epsilon4 allele had lower Abeta1-42 (p<0.001) levels than those without a epsilon4 allele. The combination of t-tau and Abeta1-42 is a robust and reliable assay that may be useful in discriminating cases at risk for AD such as ApoE epsilon4 allele carriers from nAD patients or from age-matched control subjects.     

Genetic variation in BIN1 gene and Alzheimer's disease risk in Han Chinese individuals

Genome-wide association studies have identified the bridging integrator 1 (BIN1) gene as the most important genetic susceptibility locus in late-onset Alzheimer's disease (LOAD) after apolipoprotein E for individuals of European ancestry. To further characterize this association and to isolate the variants within BIN1 contributing to LOAD in Han Chinese individuals, we conducted a 2-step design study in our cohort of 1133 LOAD patients and 1159 control subjects. Sequencing analysis identified 44 variants within BIN1. Follow-up genotyping analysis revealed that a novel missense mutation P318L appeared to exert risk effect for development of LOAD; and rs67327804 was also significantly associated with LOAD risk even after adjusting for age, gender, and apolipoprotein E ε4 status. Haplotype analysis confirmed that the “GA” haplotype derived from single-nucleotide polymorphisms in rs67327804 and rs1060743 showed a 1.4-fold increased risk of LOAD. Our findings provided the first independent evidence that variants in BIN1 were significantly associated with LOAD in Han Chinese individuals.     

质粒型单纯疱疹病毒载体的构建及其在真核细胞中的表达

利用基因工程技术构建成功质粒型Ⅰ型单纯疱疹病毒（ＨＳＶ－１）载体ｐＨＳＶ，其中含有ＨＳＶ－１包装信号序列和ＨＳＶ－１复制起点，以及ＨＳＶ－１ＩＥ６８启动子。为验证其构建是否成功，在其ＩＥ６８启动子下游的多克隆位点上插入了Ｅ．ｃｏｌｉＬａｃＺ基因，构建成ｐＨＳＶＬ质粒。用ＨＳＶ－１温度敏感株（ｔｓＫ株）超感染传代细胞后，将这种质粒转染入该细胞，ｐＨＳＶＬ可在辅助病毒ＨＳＶ－１ｔｓＫ（允许温度为３１℃）存在的条件下被包装成病毒颗粒，由此得到的混合病毒含有ＨＳＶ－１ｔｓＫ和ｐＨＳＶＬ假病毒颗粒，收获后再感染培养的Ｖｅｒｏ细胞，原位检测β－半乳糖苷酶活性呈阳性。同时用ｐＨＳＶＬ病毒接种体外培养的ＳＤ大鼠胚胎脊髓运动神经元，用Ｘ－ｇａｌ原位检测β－半乳糖苷酶的活性，亦发现有阳性的神经元存在。说明载体ｐＨＳＶＬ携带的报告基因ｌａｃＺ在这两种真核细胞中均得以正确表达。报告基因可为其它目的基因所代替，可用于神经生理、病理以及神经系统疾病基因治疗的实验研究。