Sex-Specific Regulation of ß-Secretase: A Novel Estrogen Response Element (ERE)-Dependent Mechanism in Alzheimer's Disease.

Women have a higher prevalence and incidence of Alzheimer's disease (AD) than age-matched men, and loss of estrogen might be partially responsible for the higher risk of AD in aged women. While ß-secretase (BACE1) plays an important role in AD pathogenesis, whether BACE1 involved the sex difference in AD pathology remains unclear. This study investigated the hypothesis that estrogen regulates BACE1 transcription via the estrogen response element (ERE) and designated pathways. Using estrogen receptor (ER) knock-out mice and mutagenesis of EREs in HEK293 cells, we demonstrated sex-specific inhibition of BACE1 transcription by estrogen via direct binding to ERE sites and ERα. We also used a repressor of estrogen receptor activity (REA) and showed that an REA-ERE complex downregulated BACE1. A chromatin immunoprecipitation assay analysis determined that all three EREs at the BACE1 promoter were required for estradiol-mediated downregulation of BACE1 transcription in mice. Last, we confirmed the impairment of the REA pathway in the cortex of female AD patients. Our study identified an estrogen-specific BACE1 transcriptional regulation pathway from cell and animal models to AD patients.SIGNIFICANCE STATEMENT With the increase in the aging population and Alzheimer's disease worldwide, an urgent need to find effective approaches to treat or prevent AD. Women have a higher prevalence and incidence of AD than men. Identification of the sex-specific risk for AD may be valuable for disease prevention. This study evaluated several estrogen response element (ERE) sites on the promoter of ß-secretase (BACE1), a key enzyme for AD pathology. We demonstrated that estrogen downregulated BACE1 transcription through direct binding and complex formation with ERE and cofactors. Our novel findings provide evidence that an estrogen supplement may decrease the risk of AD in menopausal and postmenopausal women. Furthermore, this study demonstrates the "sex-specific" mechanisms of BACE1 as a role in AD pathogenesis.

MMP9 modulation improves specific neurobehavioral deficits in a mouse model of Alzheimer's disease.

BACKGROUND: Matrix metallopeptidase 9 (MMP9) has been implicated in a variety of neurological disorders, including Alzheimer's disease (AD), where MMP9 levels are elevated in the brain and cerebrovasculature. Previously our group demonstrated apolipoprotein E4 (apoE4) was less efficient in regulating MMP9 activity in the brain than other apoE isoforms, and that MMP9 inhibition facilitated beta-amyloid (Aß) elimination across the blood-brain barrier (BBB) METHODS: In the current studies, we evaluated the impact of MMP9 modulation on Aß disposition and neurobehavior in AD using two approaches, (1) pharmacological inhibition of MMP9 with SB-3CT in apoE4 x AD (E4FAD) mice, and (2) gene deletion of MMP9 in AD mice (MMP9KO/5xFAD) RESULTS: Treatment with the MMP9 inhibitor SB-3CT in E4FAD mice led to reduced anxiety compared to placebo using the elevated plus maze. Deletion of the MMP9 gene in 5xFAD mice also reduced anxiety using the open field test, in addition to improving sociability and social recognition memory, particularly in male mice, as assessed through the three-chamber task, indicating certain behavioral alterations in AD may be mediated by MMP9. However, neither pharmacological inhibition of MMP9 or gene deletion of MMP9 affected spatial learning or memory in the AD animals, as determined through the radial arm water maze. Moreover, the effect of MMP9 modulation on AD neurobehavior was not due to changes in Aß disposition, as both brain and plasma Aß levels were unchanged in the SB-3CT-treated E4FAD animals and MMP9KO/AD mice compared to their respective controls. CONCLUSIONS: In total, while MMP9 inhibition did improve specific neurobehavioral deficits associated with AD, such as anxiety and social recognition memory, modulation of MMP9 did not alter spatial learning and memory or Aß tissue levels in AD animals. While targeting MMP9 may represent a therapeutic strategy to mitigate aspects of neurobehavioral decline in AD, further work is necessary to understand the nature of the relationship between MMP9 activity and neurological dysfunction.

Novel, natural allosteric inhibitors and enhancers of Candida rugosa lipase activity.

Candida rugosa lipase (CRL) is an enzyme commonly used in medicinal and biotechnological applications. Allosteric modulators of CRL could aid in modifying lipase-related diseases as well as improving biotechnological processes. Thus, a combinatorial approach of computational in-silico and high-throughput in-vitro screening was used to identify allosteric modulators of CRL. The screening of natural product libraries resulted in 132 compounds of which 53 were tested in-vitro. Subsequently, four inhibitors and three enhancers were identified of which rutin and cynaroside represented the strongest inhibitors of CRL activity (IC50: 227 ± 26 µM and 446 ± 15 µM, respectively) and NP-008496 the strongest enhancer (EC50: 425 ± 18 µM). All three compounds were predicted to bind the same allosteric site suggesting a common mechanism. Therefore, the present study demonstrated a reliable work-flow, identified an allosteric site of CRL and determined inhibitors and enhancers with numerous potential medical and biotechnological applications.

A fast, miniaturised in-vitro assay developed for quantification of lipase enzyme activity.

The discovery of allosteric modulators is a multi-disciplinary approach, which is time- and cost-intensive. High-throughput screening combined with novel computational tools can reduce these factors. Thus, we developed an enzyme activity assay, which can be included in the drug discovery work-flow subsequent to the in-silico library screening. While the in-silico screening yields in the identification of potential allosteric modulators, the developed in-vitro assay allows for the characterisation of them. Candida rugosa lipase (CRL), a glyceride hydrolysing enzyme, has been selected for the pilot development. The assay conditions were adjusted to CRL's properties including pH, temperature and substrate specificity for two different substrates. The optimised assay conditions were validated and were used to characterise Tropolone, which was identified as an allosteric modulator. In conclusion, the assay is a reliable, reproducible, and robust tool, which can be streamlined with in-silico screening and incorporated in an automated high-throughput screening workflow.

Plasma cytokine IL-6 levels and subjective cognitive decline: preliminary findings.

OBJECTIVE: Detection of Alzheimer's disease (AD) prior to clinical inception will be paramount for introducing disease modifying treatments. We have begun collecting baseline characteristics of a community cohort for longitudinal assessment and testing of antecedent blood-based biomarkers. We describe the baseline visit from the first 131 subjects in relationship to a commonly described cytokine, interleukin 6 (IL-6). METHODS: Subjects from the community presented for a free memory screening with varying degrees of memory concern. We quantified the baseline plasma levels of the cytokine IL-6 and assessed cognition (Montreal Cognitive Assessment, MoCA) and mood (Geriatric Depression Scale, GDS) in relationship to their memory concern. RESULTS: Baseline MoCA scores were inversely related to age, and this association was influenced by an AD risk factor, Apolipoprotein E (APOE4) carrier status. The degree of subjective cognitive decline correlated with GDS and was inversely related to MoCA scores. Interleukin 6 levels were related to age, body mass index, and years of education. CONCLUSIONS: It will be important to assess how these baseline IL-6 levels and forthcoming novel biomarkers relate to future cognitive decline. Copyright © 2017 John Wiley & Sons, Ltd.

Identification of Telomerase-activating Blends From Naturally Occurring Compounds.

Context • Telomeres are repeated deoxyribonucleic acid (DNA) sequences (TTAGGG) that are located on the 5' ends of chromosomes, and they control the life span of eukaryotic cells. Compelling evidence has shown that the length of a person's life is dictated by the limited number of times that a human cell can divide. The enzyme telomerase has been shown to bind to and extend the length of telomeres. Thus, strategies for activating telomerase may help maintain telomere length and, thus, may lead to improved health during aging. Objective • The current study intended to investigate the effects of several natural compounds on telomerase activity in an established cell model of telomere shortening (ie, IMR90 cells). Design • The research team designed an in vitro study. Setting • The study was conducted at Roskamp Institute in Sarasota, FL, USA. Intervention • The tested single compounds were (1) α-lipoic acid, (1) green tea extract, (2) dimethylaminoethanol L-bitartrate (DMAE L-bitartrate), (3) N-acetyl-L-cysteine hydrochloride (HCL), (4) chlorella powder, (5) L-carnosine, (6) vitamin D3, (7) rhodiola PE 3%/1%, (8) glycine, (9) French red wine extract, (10) chia seed extract, (11) broccoli seed extract, and (12) Astragalus (TA-65). The compounds were tested singly and as blends. Outcome Measures • Telomerase activity for single compounds and blends of compounds was measured by the TeloTAGGG telomerase polymerase chain reaction (PCR) enzyme-linked immunosorbent assay (ELISA). The 4 most potent blends were investigated for their effects on cancer-cell proliferation and for their potential effects on the cytotoxicity and antiproliferative activity of a chemotherapeutic agent, the topoisomerase I inhibitor topotecan. The benefits of 6 population doublings (PDs) were measured for the single compounds, and the 4 blends were compared to 3 concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Results • Certain of the compounds increased telomerase activity, and combinations of the top-ranking compounds were able to increase telomerase activity significantly, from 51% to 290%, relative to controls. Conclusions • The results have confirmed that many naturally occurring compounds hold the potential to activate telomerase and that certain of those compounds have demonstrated synergistic effects to produce more potent blends. Given the relationship between telomere shortening, aging, and the decline of tissue function, it is reasonable to hypothesize that such telomerase-activating blends may have health-promoting benefits, particularly in relation to aging-associated conditions. Further investigation of such blends in human studies that are designed to evaluate safety and the effects on telomere length are thus warranted.

The spleen tyrosine kinase (Syk) regulates Alzheimer amyloid-ß production and Tau hyperphosphorylation.

We have previously shown that the L-type calcium channel (LCC) antagonist nilvadipine reduces brain amyloid-ß (Aß) accumulation by affecting both Aß production and Aß clearance across the blood-brain barrier (BBB). Nilvadipine consists of a mixture of two enantiomers, (+)-nilvadipine and (-)-nilvadipine, in equal proportion. (+)-Nilvadipine is the active enantiomer responsible for the inhibition of LCC, whereas (-)-nilvadipine is considered inactive. Both nilvadipine enantiomers inhibit Aß production and improve the clearance of Aß across the BBB showing that these effects are not related to LCC inhibition. In addition, treatment of P301S mutant human Tau transgenic mice (transgenic Tau P301S) with (-)-nilvadipine reduces Tau hyperphosphorylation at several Alzheimer disease (AD) pertinent epitopes. A search for the mechanism of action of (-)-nilvadipine revealed that this compound inhibits the spleen tyrosine kinase (Syk). We further validated Syk as a target-regulating Aß by showing that pharmacological inhibition of Syk or down-regulation of Syk expression reduces Aß production and increases the clearance of Aß across the BBB mimicking (-)-nilvadipine effects. Moreover, treatment of transgenic mice overexpressing Aß and transgenic Tau P301S mice with a selective Syk inhibitor respectively decreased brain Aß accumulation and Tau hyperphosphorylation at multiple AD relevant epitopes. We show that Syk inhibition induces an increased phosphorylation of the inhibitory Ser-9 residue of glycogen synthase kinase-3ß, a primary Tau kinase involved in Tau phosphorylation, by activating protein kinase A, providing a mechanism explaining the reduction of Tau phosphorylation at GSK3ß-dependent epitopes following Syk inhibition. Altogether our data highlight Syk as a promising target for preventing both Aß accumulation and Tau hyperphosphorylation in AD.

Baseline serum brain-derived neurotrophic factor association with future cognition in community-dwelling older adults undergoing annual memory screening.

OBJECTIVES: It has been shown that peripheral measures of brain-derived neurotrophic factor (BNDF), an important neurotrophin instrumental to the biology of learning, may contribute to predicting cognitive decline. However, the two primary forms of BDNF, mature (mBDNF) and pro (proBDNF), and how they contribute to cognition longitudinally has not been well studied. METHODS: Eighty-two older adults (average age 72.2 ± 6.4 years) provided blood samples at two time points separated on average by 4.2 years while participating in an annual memory screening that included the MoCA (Montreal Cognitive Assessment) and GDS (Geriatric Depression Scale). Both mBDNF and proBDNF from serum were quantified at each time point. Whole blood samples were genotyped for APOE and BDNF Val66Met. RESULTS: Using logistic regression analysis controlling for age, sex, baseline MoCA score, APOE, and BDNF, higher baseline mBDNF was associated with subjects whose screening score was near maximum or maximum (as defined by MoCA score of 29 or 30) at the second collection visit. APOE was a significant contributing factor; however, BDNF Val66Met was not. Using a similar logistic regression analysis, baseline proBDNF was not found to be associated with future cognition. DISCUSSION: This study further supports that mBDNF measured in the serum of older adults may reflect a protective role while proBDNF requires further investigation.

Bacopa monnieri supplementation has no effect on serum brain-derived neurotrophic factor levels but beneficially modulates nuclear factor kappa B and cyclic AMP response element-binding protein levels in healthy elderly subjects.

Background and Aim: Bacopa monnieri is an Ayurvedic herb that has been used for multiple conditions, most notably to augment cognition, particularly memory and attention. Multiple mechanisms, including raising brain-derived neurotrophic factor (BDNF), have been proposed and investigated in animal models that require translational studies in humans. Methods: Bacopa was administered in an open-labeled study to cognitively healthy controls over a 3-month period. Cognition and mood were assessed using the Montreal Cognitive Assessment (MoCA) and geriatric depression scale (GDS) at the baseline and 3-month visit. Laboratories were assessed for safety and serum levels of mature (mBDNF) and proBDNF were quantified. In a subset of subjects, intracellular signaling processes were assessed using western blot analysis. Results: Bacopa was provided to 35 subjects and was well-tolerated except for 4 (11%) subjects who early terminated due to known, reversible, and gastrointestinal side effects (i.e., nausea, diarrhea). Over the 3 months, the GDS and the total MoCA did not significantly change; however, the delayed-recall subscale significantly improved (baseline: 3.8 ± 1.2, 3-months: 4.3 ± 0.9; P = 0.032). Serum mBDNF and proBDNF levels did not significantly change. Cyclic AMP response element-binding protein (CREB) phosphorylation significantly increased (P = 0.028) and p65 nuclear factor kappa B (NF-κB) phosphorylation significantly decreased (P = 0.030). Conclusion: These results suggest that Bacopa may exert an anti-inflammatory effect through NF-κB and improve intracellular signaling processes associated with synaptogenesis (CREB). The future placebo-controlled studies are recommended. Relevance for Patients: B. monnieri will require larger, blinded trials to better understand potential mechanisms, interactions, and utilization.

Impact of gulf war toxic exposures after mild traumatic brain injury.

Chemical and pharmaceutical exposures have been associated with the development of Gulf War Illness (GWI), but how these factors interact with the pathophysiology of traumatic brain injury (TBI) remains an area of study that has received little attention thus far. We studied the effects of pyridostigmine bromide (an anti-nerve agent) and permethrin (a pesticide) exposure in a mouse model of repetitive mild TBI (r-mTBI), with 5 impacts over a 9-day period, followed by Gulf War (GW) toxicant exposure for 10 days beginning 30 days after the last head injury. We then assessed the chronic behavioral and pathological sequelae 5 months after GW agent exposure. We observed that r-mTBI and GWI cumulatively affect the spatial memory of mice in the Barnes maze and result in a shift of search strategies employed by r-mTBI/GW exposed mice. GW exposure also produced anxiety-like behavior in sham animals, but r-mTBI produced disinhibition in both the vehicle and GW treated mice. Pathologically, GW exposure worsened r-mTBI dependent axonal degeneration and neuroinflammation, increased oligodendrocyte cell counts, and increased r-mTBI dependent phosphorylated tau, which was found to colocalize with oligodendrocytes in the corpus callosum. These results suggest that GW exposures may worsen TBI-related deficits. Veterans with a history of both GW chemical exposures as well as TBI may be at higher risk for worse symptoms and outcomes. Subsequent exposure to various toxic substances can influence the chronic nature of mTBI and should be considered as an etiological factor influencing mTBI recovery.

Exogenous lipase administration alters gut microbiota composition and ameliorates Alzheimer's disease-like pathology in APP/PS1 mice.

Alzheimer's disease (AD) represents the most common form of dementia in the elderly with no available disease modifying treatments. Altered gut microbial composition has been widely acknowledged as a common feature of AD, which potentially contributes to progression or onset of AD. To assess the hypothesis that Candida rugosa lipase (CRL), which has been shown to enhance gut microbiome and metabolite composition, can rebalance the gut microbiome composition and reduce AD pathology, the treatment effects in APPswe/PS1de9 (APP/PS1) mice were investigated. The analysis revealed an increased abundance of Acetatifactor and Clostridiales vadin BB60 genera in the gut; increased lipid hydrolysis in the gut lumen, normalization of peripheral unsaturated fatty acids, and reduction of neuroinflammation and memory deficits post treatment. Finally, we demonstrated that the evoked benefits on memory could be transferred via fecal matter transplant (FMT) into antibiotic-induced microbiome-depleted (AIMD) wildtype mice, ameliorating their memory deficits. The findings herein contributed to improve our understanding of the role of the gut microbiome in AD's complex networks and suggested that targeted modification of the gut could contribute to amelioration of AD neuropathology.

Selective antihypertensive dihydropyridines lower Aß accumulation by targeting both the production and the clearance of Aß across the blood-brain barrier.

Several large population-based or clinical trial studies have suggested that certain dihydropyridine (DHP) L-type calcium channel blockers (CCBs) used for the treatment of hypertension may confer protection against the development of Alzheimer disease (AD). However, other studies with drugs of the same class have shown no beneficial clinical effects. To determine whether certain DHPs are able to impact underlying disease processes in AD (specifically the accumulation of the Alzheimer Aß peptide), we investigated the effect of several antihypertensive DHPs and non-DHP CCBs on Aß production. Among the antihypertensive DHPs tested, a few, including nilvadipine, nitrendipine and amlodipine inhibited Aß production in vitro, whereas others had no effect or raised Aß levels. In vivo, nilvadipine and nitrendipine acutely reduced brain Aß levels in a transgenic mouse model of AD (Tg PS1/APPsw) and improved Aß clearance across the blood-brain barrier (BBB), whereas amlodipine and nifedipine were ineffective showing that the Aß-lowering activity of the DHPs is independent of their antihypertensive activity. Chronic oral treatment with nilvadipine decreased Aß burden in the brains of Tg APPsw (Tg2576) and Tg PS1/APPsw mice, and also improved learning abilities and spatial memory. Our data suggest that the clinical benefit conferred by certain antihypertensive DHPs against AD is unrelated to their antihypertensive activity, but rely on their ability to lower brain Aß accumulation by affecting both Aß production and Aß clearance across the BBB.

Adaptive Immune Responses Associated with the Central Nervous System Pathology of Gulf War Illness.

Gulf War Illness is a multisymptomatic condition which affects 30% of veterans from the 1991 Gulf War. While there is evidence for a role of peripheral cellular and humoral adaptive immune responses in Gulf War Illness, a potential role of the adaptive immune system in the central nervous system pathology of this condition remains unknown. Furthermore, many of the clinical features of Gulf War Illness resembles those of autoimmune diseases, but the biological processes are likely different as the etiology of Gulf War Illness is linked to hazardous chemical exposures specific to the Gulf War theatre. This review discusses Gulf War chemical-induced maladaptive immune responses and a potential role of cellular and humoral immune responses that may be relevant to the central nervous system symptoms and pathology of Gulf War Illness. The discussion may stimulate investigations into adaptive immunity for developing novel therapies for Gulf War Illness.

Reduction of beta-amyloid pathology by celastrol in a transgenic mouse model of Alzheimer's disease.

BACKGROUND: Abeta deposits represent a neuropathological hallmark of Alzheimer's disease (AD). Both soluble and insoluble Abeta species are considered to be responsible for initiating the pathological cascade that eventually leads to AD. Therefore, the identification of therapeutic approaches that can lower Abeta production or accumulation remains a priority. NFkappaB has been shown to regulate BACE-1 expression level, the rate limiting enzyme responsible for the production of Abeta. We therefore explored whether the known NFkappaB inhibitor celastrol could represent a suitable compound for decreasing Abeta production and accumulation in vivo. METHODS: The effect of celastrol on amyloid precursor protein (APP) processing, Abeta production and NFkappaB activation was investigated by western blotting and ELISAs using a cell line overexpressing APP. The impact of celastrol on brain Abeta accumulation was tested in a transgenic mouse model of AD overexpressing the human APP695sw mutation and the presenilin-1 mutation M146L (Tg PS1/APPsw) by immunostaining and ELISAs. An acute treatment with celastrol was investigated by administering celastrol intraperitoneally at a dosage of 1 mg/Kg in 35 week-old Tg PS1/APPsw for 4 consecutive days. In addition, a chronic treatment (32 days) with celastrol was tested using a matrix-driven delivery pellet system implanted subcutaneously in 5 month-old Tg PS1/APPsw to ensure a continuous daily release of 2.5 mg/Kg of celastrol. RESULTS: In vitro, celastrol dose dependently prevented NFkappaB activation and inhibited BACE-1 expression. Celastrol potently inhibited Abeta1-40 and Abeta1-42 production by reducing the beta-cleavage of APP, leading to decreased levels of APP-CTFbeta and APPsbeta. In vivo, celastrol appeared to reduce the levels of both soluble and insoluble Abeta1-38, Abeta1-40 and Abeta1-42. In addition, a reduction in Abeta plaque burden and microglial activation was observed in the brains of Tg PS1/APPsw following a chronic administration of celastrol. CONCLUSIONS: Overall our data suggest that celastrol is a potent Abeta lowering compound that acts as an indirect BACE-1 inhibitor possibly by regulating BACE-1 expression level via an NFkappaB dependent mechanism. Additional work is required to determine whether chronic administration of celastrol can be safely achieved with cognitive benefits in a transgenic mouse model of AD.

CD40/CD40L interaction induces Abeta production and increases gamma-secretase activity independently of tumor necrosis factor receptor associated factor (TRAF) signaling.

CD40, a member of tumor necrosis factor receptor superfamily, and its cognate ligand CD40L are both elevated in the brain of Alzheimer's disease (AD) patients compared to controls. We have shown that pharmacological or genetic interruption of CD40/CD40L interaction results in mitigation of AD-like pathology in vivo in transgenic AD mouse models, and in vitro. Recently, we showed that CD40L stimulation could increase Abeta levels via NFkappaB signaling, presumably through TRAFs. In the present work, using CD40 mutants, we show that CD40L can increase levels of Abeta(1-40), Abeta(1-42), sAPPbeta, sAPPalpha and CTFbeta independently of TRAF signaling. We report an increase in mature/immature APP ratio after CD40L treatment of CD40wt and CD40-mutant cells, reflecting alterations in APP trafficking. In addition, results from CD40L treatment of a neuroblastoma cell line over-expressing the C-99 APP fragment suggest that CD40L has an effect on gamma-secretase. Furthermore, inhibition of gamma-secretase activity significantly reduces sAPPbeta levels in the CD40L treated HEK/APPsw CD40wt and the CD40-mutant cells. The latter suggests CD40/CD40L interaction primarily acts on gamma-secretase and affects beta-secretase via a positive feedback mechanism. Taken together, our data suggest that CD40/CD40L interaction modulates APP processing independently of TRAF signaling.

Candida rugosa lipase alters the gastrointestinal environment in wild-type mice.

Diet and commercially available supplements can significantly impact the gut microbial composition; however, the effects of supplements often lack scientific data demonstrating the effects on healthy and diseased individuals. Hence, it was investigated, whether a frequently used supplement in humans, Candida rugosa lipase (CRL), gets delivered active beyond the stomach in the intestinal tract of C57BL/6 J mice and its impact on the gut microbial community and environment. We showed for the first time the movement of CRL in an active state through the mouse digestive tract by determination of intestinal CRL activity and free fatty acids concentrations. The short- and long-term administration of CRL resulted in significant alterations of the gut microbiome, favoring the growth of, for instance, Verrucomicrobia but also other species associated with normal body mass index (BMI) or butyrate expression, both considered beneficial. In addition, we showed that these changes persisted after supplementation and that gut barrier integrity was unaffected by the treatment. In conclusion, CRL can be delivered in an active state beyond the stomach and supplementation altered the murine gut microbiome favoring beneficial bacterial species, which may be of relevance in humans in healthy but also potentially in disease states.

The Influence of Baseline Alzheimer's Disease Severity on Cognitive Decline and CSF Biomarkers in the NILVAD Trial.

We examined the effects of a dihydropyridine calcium channel blocker nilvadipine with anti-inflammatory properties on cognition and cerebrospinal fluid (CSF) biomarkers by baseline Alzheimer's disease (AD) severity. Exploratory analyses were performed on the dataset (n = 497) of a phase III randomized placebo-controlled trial to examine the response to nilvadipine in AD subjects stratified by baseline AD severity into very mild (MMSE ≥ 25), mild (MMSE 20-24) and moderate AD (MMSE < 20). The outcome measures included total and subscale scores of the Alzheimer's Disease Assessment Scale Cognitive 12 (ADAS-Cog 12), the Clinical Dementia Rating Scale sum of boxes (CDR-sb) and the AD composite score (ADCOMS). Cerebrospinal fluid biomarkers Aß38, Aß40, Aß42, neurofilament light chain (NFL), neurogranin, YKL-40, total tau and P181 tau (ptau) were measured in a subset of samples (n = 55). Regression analyses were adjusted for confounders to specifically examine the influence of nilvadipine and baseline AD severity on cognitive outcomes over 78-weeks. Compared to their respective placebo-controls, nilvadipine-treated, very mild AD subjects showed less decline, whereas moderate AD subjects showed a greater cognitive decline on the ADAS-Cog 12 test and the ADCOMS. A lower decline was observed after nilvadipine treatment for a composite memory trait in very mild AD subjects and a composite language trait in mild AD subjects. Cerebrospinal fluid Aß42/Aß40 ratios were increased in mild AD and decreased in moderate AD patients treated with nilvadipine, compared to their respective controls. Among moderate AD subjects, levels of ptau, total tau, neurogranin and YKL-40 increased in subjects treated with nilvadipine compared to placebo. These studies suggest that baseline AD severity influenced the treatment outcome in the NILVAD trial and that future clinical trials of nilvadipine should be restricted to mild and very mild AD patients. Trial Registration: NCT02017340 Registered 20 December 2013, https://clinicaltrials.gov/ct2/show/NCT02017340 EUDRACT Reference Number 2012-002764-27 Registered 04 February 2013, https://www.clinicaltrialsregister.eu/ctr-search/search?query=2012-002764-27.

Serum Abeta levels as predictors of conversion to mild cognitive impairment/Alzheimer disease in an ADAPT subcohort.

Recent evidence suggests an association of beta-amyloid (Abeta) with vascular risk factors and the medications to treat them, which could potentially obfuscate the usefulness of Abeta for prediction of mild cognitive impairment (MCI) or Alzheimer disease (AD). In a subcohort from the Alzheimer's Disease Anti-inflammatory Prevention Trial (enriched for family history of AD), we investigated whether systolic blood pressure, total cholesterol, triglycerides, serum creatinine, apolipoprotein E, and use of statins and antihypertensives influenced the predictive value of serum Abeta for MCI/AD during a 2-year period. We collected blood samples to quantify serum Abeta from cognitively normal participants (n = 203) at baseline and ascertained the outcome of MCI/AD (n = 24) for a period of approximately 2 years. In an unadjusted model, the lowest quartile of Abeta(1-42) (hazard ratio [HR] = 2.93, 95% CI [1.02-8.32], P = 0.04) and of the Abeta(1-42)/Abeta(1-40) ratio (HR = 3.53, 95% CI [1.24-10.07], P = 0.02), compared with the highest quartile, predicted conversion to MCI/AD, but no impact of Abeta(1-40) was observed. No relationship between nonsteroidal antiinflammatory drug interventions and Abeta on MCI/AD risk was evident. Once data were adjusted for potential confounders (age, sex, and education), vascular risk factors, and the medications listed above, the lowest quartiles of Abeta(1-42) (HR = 4.47, 95% CI [1.39-14.39], P = 0.01), and of the Abeta(1-42/)Abeta(1-40) ratio (HR 4.87, 95% CI [1.50-15.87], P = 0.01) became strong predictors of conversion to MCI/AD. In this subcohort of individuals at risk for AD, the association of Abeta with vascular risk factors and medications to treat these conditions did not interfere with Abeta's predictive value for MCI/AD.

High serum Abeta and vascular risk factors in first-degree relatives of Alzheimer's disease patients.

The main objective of this study was to determine whether elevated blood beta-amyloid (Abeta) levels among the first-degree relatives of patients with Alzheimer's Disease (AD) are associated with vascular risk factors of AD. Serum Abeta was measured in samples from 197 cognitively normal first-degree relatives of patients with AD-like dementia. Study participants were recruited as part of an ancillary study of the Alzheimer's Disease Anti-inflammatory Prevention Trial (ADAPT subpopulation). The ADAPT subpopulation was found to be similar in age, sex, and ethnicity to another cognitively normal cohort (n = 98). Using cross-sectional analyses, we examined the association of Abeta with blood pressure, lipid levels, apolipoprotein E genotypes, and the use of prescribed medication to treat vascular risk factors in the ADAPT subpopulation. Abeta(1-40) was positively associated with age, use of antihypertensives, and serum creatinine, and we observed a marginal negative interaction on Abeta(1-40) associated with systolic blood pressure and use of antihypertensives. Serum Abeta(1-42) was associated with statin use and a positive correlation of Abeta (1-42) with HDL was observed among statin nonusers. These findings suggest that high Abeta in the periphery among the family history-enriched cohorts may be due to enrichment of vascular risk factors and may reflect presymptomatic AD pathology. It remains to be determined whether the association of Abeta with medications used for treating vascular risk factors indicates prevention of AD. Longitudinal evaluation of blood Abeta in this cohort will provide a better understanding of the significance of this association in AD etiology.

Proteomic Identification of Pathways Responsible for the Estradiol Therapeutic Window in AD Animal Models.

Benefits and risks were reported for hormone therapy (HT) to prevent chronic disease, including Alzheimer's disease (AD). While the Women's Health Initiative (WHI) found no protective effect of HT on the cognitive function of women whose treatment was initiated far past the onset of menopause, other studies showed reduced risk of AD with midlife treatment, versus increased risk of AD with late treatment. These suggest a critical window during which estradiol must be administered to prevent cognitive decline and AD in women. Our published work supports this, by demonstrating that early and long-term estradiol treatment improves cognitive function and reduce Aß accumulation in AD mouse models with estradiol deficiency, while there is no effect of late and short-term estradiol treatment on AD neuropathogenesis. However, little is known about the molecular mechanisms underlying the critical window and whether different protein networks are responsible for the brain estradiol deficiency-associated risk of AD in females. In this study, we used proteomics to identify target protein pathways that are activated during the estradiol therapeutic window in AD mouse model. Our results showed that different signaling pathways were involved in the regulatory effects of estradiol on MAP1A and hemoglobin α. Estradiol treatment increased the level of MAP1A through the phosphorylation of ERK1/2 and increased the level of hemoglobin α through the phosphorylation of AKT. This study has provided molecular insights into the "critical window" theory and identifies specific target proteins of therapeutic responsiveness that may lead to improved treatment strategies and optimal estradiol therapy.