Journal of Alzheimer's Disease - Volume 11, issue 3

Authors: Khachaturian, Zaven S.

Article Type: Obituary

DOI: 10.3233/JAD-2007-11301

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 257-260, 2007

Authors: Sathishkumar, K. | Xi, Xiaochun | Martin, Roy | Uppu, Rao M.

Article Type: Research Article

Abstract: Aldehydic products from ozonation of cholesterol and peroxidation of phospholipids have been shown to accelerate aggregation of amyloid-β (Aβ) in vitro. Here, we show that 3β-hydroxy-5-oxo-5,6-secocholestan-6-al (ChSeco), an ozonation product of cholesterol, induces Aβ aggregation, generation of reactive oxygen species (ROS), and cytotoxicity in murine GT1-7 hypothalamic neurons. The formation of Aβ aggregates in situ was dose-dependent at ChSeco concentrations ranging from 1 to 20 μM. The increase in insoluble Aβ aggregates at increasing concentrations of ChSeco was accompanied by a decrease in soluble Aβ as evidenced by Western blot analysis. The formation of ROS in neuronal cells was found …to be dose- and time-dependent with the magnitude being higher at 20 μM compared to 10 μM ChSeco or untreated controls. The increase in ROS was associated with depletion of GSH. The cytotoxicity induced by ChSeco involved changes in phosphatidylserine translocation, DNA fragmentation, and caspase 3/7 activity that are characteristic of apoptosis. Pretreatment of neuronal cells with Trolox, a water-soluble analog of α-tocopherol offered partial, but significant protection against ChSeco-induced cell death, whereas, N-acetyl-L-cysteine (NAC) completely prevented the cytotoxic effects of ChSeco. NAC and Trolox were without any effects on ChSeco-induced Aβ aggregation. Fibrillogenesis inhibitors, which inhibited Aβ aggregation, did not inhibit cell death induced by ChSeco, implying that ROS generation, and not Aβ aggregation, plays a major role in the observed cytotoxicity. However, since Alzheimer's and other neurodegenerative diseases are slow and progressive, the formation of Aβ aggregates in vivo by ChSeco may have long-term pathological consequences. Show more

Keywords: Amyloid aggregation, cholesterol secoaldehyde, neuronal apoptosis, oxysterols, ozone, reactive oxygen species

DOI: 10.3233/JAD-2007-11302

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 261-274, 2007

Authors: Fuso, Andrea | Cavallaro, Rosaria A. | Zampelli, Alessandro | D'Anselmi, Fabrizio | Piscopo, Paola | Confaloni, Annamaria | Scarpa, Sigfrido

Article Type: Research Article

Abstract: Multiple aspects of homocysteine metabolism were studied to understand the mechanism responsible for hyperhomocysteinemia toxicity in Alzheimer disease. Besides oxidative stress and vascular damage, homocysteine has also a great importance in regulating DNA methylation through S-adenosylmethionine, the main methyl donor in eukaryotes. Alterations of S-adenosylmethionine and methylation were evidenced in Alzheimer disease and in elderly. In order to clarify whether DNA methylation can provide the basis for amyloid-β overproduction, we used human SK-N-BE neuroblastoma and A172 glioblastoma cell lines. We tested the effects of folate, B12 and B6 deprivation and S-adenosylmethionine addition on methylation metabolism. Our results indicate that homocysteine …accumulation induced through vitamin B deprivation could impair the “Methylation Potential” with consequent presenilin 1, BACE and amyloid-β upregulation. Moreover, we found that homocysteine alterations had an effect on neuroblastoma but not on glioblastoma cells; this suggests a possible differential role of the two cell types in Alzheimer disease. Show more

Keywords: S-adenosylmethionine, homocysteine, folate, vitamin B, DNA methylation, amyloid processing, presenilin 1

DOI: 10.3233/JAD-2007-11303

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 275-290, 2007

Authors: Friedman, Orrie M. | Matsudaira, Paul | Reis Jr., Arthur H. | Simister, Neil | Correia, Ivan | Kew, David | Wei, Julie Y. | Pochapsky, Thomas

Article Type: Research Article

Abstract: Extensive testing of hydrolysates of commercially available organosilanes has identified a number of bifunctional organosiloxane compounds that show potential as therapeutics for treatment of diseases characterized by amyloid deposition such as Alzheimer's disease (AD). All of these compounds protect from and/or reverse the metal-induced aggregation of amyloid Aβ(1–42) peptide in dynamic light scattering (DLS) assays in trifluoroethanol (TFE) solutions, protect from and/or reverse the metal-induced loss of α-helical structure in TFE solutions of amyloid Aβ(1–42) as measured by circular dichroism (CD), and are able to cross blood-brain barrier models at rates above background using Caco-2 and MDCK cell permeation assays. …Based on these studies, we conclude that members of this class of bifunctional organosiloxanes are promising candidates for testing in treatment and/or prevention of AD and other diseases characterized by amyloid deposition. Show more

Keywords: Aluminum, Alzheimer disease, amyloid-β, treatment

DOI: 10.3233/JAD-2007-11304

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 291-300, 2007

Authors: Exley, Christopher

Article Type: Article Commentary

DOI: 10.3233/JAD-2007-11305

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 301-302, 2007

Authors: Friedman, Orrie M. | Matsudaira, Paul | Reis Jr., Arthur H. | Simister, Neil | Pochapsky, Thomas

Article Type: Reply

DOI: 10.3233/JAD-2007-11306

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 303-304, 2007

Authors: Thirumangalakudi, Lakshmi | Yin, Linda | Rao, Haripriya Vittal | Grammas, Paula

Article Type: Research Article

Abstract: Neuronal cell loss is a critical feature of age-related neurodegenerative diseases such as Alzheimer's disease (AD). In the AD brain, a marked increase in pro-inflammatory cytokines and chemokines, including IL-8, has been documented. The objective of this study was to determine the effect of IL-8 on cell viability and expression of neurotoxic, apoptotic, and cell cycle proteins in cultured neurons. Incubation of cultured neurons with IL-8 for 24 h resulted in neuronal cell death. RT-PCR analysis of primary rat neuronal cultures treated with IL-8 for 24 h showed induction of genes for matrix metalloproteinases (MMP-2 and MMP-9), proinflammatory proteases with …neurotoxic properties. Gelatin zymography demonstrated IL-8 induced MMP-2 and MMP-9 activity. Western blot analysis showed that IL-8 also increased levels of the pro-apoptotic protein Bim (Bcl-2-interacting mediator of cell death). In addition, message levels of the cell cycle protein cyclin D1, an early marker for G1/S transition and a protein implicated as a regulator of neuronal apoptosis, were elevated after IL-8 exposure. These results suggest that IL-8 could be an important mediator of neuronal death in AD both via its effects on release of neurotoxins such as MMPs as well as by induction of cell cycle and pro-apoptotic proteins. Show more

Keywords: Inflammation, neurotoxicity, protease, apoptosis, cell cycle

DOI: 10.3233/JAD-2007-11307

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 305-311, 2007

Authors: Debanne, Sara M. | Bielefeld, Roger A. | Cheruvu, Vinay K. | Fritsch, Thomas | Rowland, Douglas Y.

Article Type: Research Article

Abstract: The discrepancy between cohort and case-control studies regarding the association between smoking and Alzheimer's disease (AD) has been attributed to the competing risk of early mortality of smokers. A simulation study was conducted to show that the bias favoring smokers acts also on cohort studies. In the model, individuals {grow older} and have smoking habits according to published year-age-gender-specific patterns, with morbidity and mortality according to their demographic and smoking profiles. Those individuals dying of smoking-related causes (“phantoms”) remain at risk of AD and of death from other causes. Three scenarios were considered: no association of AD and smoking, increased …risk for smokers, and decreased risk for smokers. For each simulation of a cohort study, two incidence density ratios (IDR) were computed: one including the phantoms that developed AD (thus ignoring smoking-related deaths) and another excluding them (thus mimicking real-life studies). For all scenarios, the simulations show that smoking-related death creates a bias, resulting in smokers having an understated risk of AD compared to non-smokers. The speculation that the conflicting results of case-control and cohort studies are solely due to the increased mortality in smokers thus appears unjustified. Other factors must also be considered to explain the discrepancy in results. Show more

Keywords: Alzheimer's disease, smoking, bias, competing risk, Markov Chain, simulation, cohort studies

DOI: 10.3233/JAD-2007-11308

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 313-321, 2007

Authors: Trenkle, Douglas L. | Shankle, William R. | Azen, Stanley P.

Article Type: Research Article

Abstract: Early detection of Alzheimer's disease and related disorders (ADRD) is important, especially in primary care settings. We compared performances of two common screening tests, the Mini-Mental State Exam (MMSE) and Clock Drawing Test (CDT), with that of the MCI Screen ({MCIS}) in 254 patients over 65. None had previous diagnosis of ADRD, and 81% were asymptomatic by Functional Assessment Staging Test ({FAST}) (FAST=1). 215 patients completed all screening tests – 141 had ⩾ 1 abnormal result, 121/141 completed standardized diagnostic assessment, and the remaining 74/215 (34%) screened entirely normally and weren't further evaluated. Potential bias due to unevaluated cases was …statistically adjusted. Among diagnosed cases: AD=43%, cerebrovascular disease=36%, other causes=21%. Bias-adjusted MCI prevalence for FAST stages 1 and 1–3 were 13.9–20.3% and 23.0–28.3%. Bias-adjusted results for the CDT, MMSE and MCIS were: clinical diagnosis validity (kappa statistic)={−0.02 (p=0.61), 0.06 (p=0.23), 0.92 (p< 0.0001)}; sensitivity={59%, 71%, 94%}; specificity={39%, 36%, 97%}; overall accuracy={54%, 62%, 96%}; positive predictive value={16%, 17%, 86%}; and negative predictive value={83%, 87%, 96%}. The MMSE and CDT were not valid for early detection, while the MCIS had high validity and accuracy in the primary care cohort. Show more

Keywords: Normal aging, mild cognitive impairment, Alzheimer's disease, prevalence, sensitivity, accuracy, early detection, primary care, receiver operating characteristic, validity

DOI: 10.3233/JAD-2007-11309

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 323-335, 2007

Authors: Petot, Grace J. | Vega, Ursula | Traore, Fatoumata | Fritsch, Thomas | Debanne, Sara M. | Friedland, Robert P. | Lerner, Alan J.

Article Type: Research Article

Abstract: The purpose of this study is to examine the relationship of height, Apolipoprotein E genotype (APOE) and Alzheimer's disease (AD). Using a case-control design, subjects were recruited from the research registry of the University Memory and Aging Center of Case Western Reserve University and University Hospitals of Cleveland. On entry to the study, height was measured on 239 probable or possible AD patients and 341 healthy controls living in northeast Ohio. Risk of AD was modeled as a function of quartile of height, APOE genotype, years of education and year of birth. Analyses were stratified by gender. For men, cases …were more likely to be shorter when compared to controls (p=0.001). There was only a small difference in mean height between AD cases and controls among women (p=0.05). For men, height in the highest quartile [>179.7 cm (70.75 in)] had a 59% lower risk of developing AD that in the lowest quartile [< 169.5 cm (66.75 in)], controlling for year of birth, and education (p=0.03). For women without an APOE ε4 allele, increasing height was associated with lower risk for AD (OR=0.88; p=0.01) but no significant association was found for women with at least one ε4 allele (OR=1.03; p=0.56). Show more

Keywords: Height, Alzheimer's disease, risk factors, mid-life

DOI: 10.3233/JAD-2007-11310

Citation: Journal of Alzheimer's Disease, vol. 11, no. 3, pp. 337-341, 2007