Quantitative mitochondrial DNA copy number determination using droplet digital PCR with single-cell resolution.

Mitochondria are involved in a number of diverse cellular functions, including energy production, metabolic regulation, apoptosis, calcium homeostasis, cell proliferation, and motility, as well as free radical generation. Mitochondrial DNA (mtDNA) is present at hundreds to thousands of copies per cell in a tissue-specific manner. mtDNA copy number also varies during aging and disease progression and therefore might be considered as a biomarker that mirrors alterations within the human body. Here, we present a new quantitative, highly sensitive droplet digital PCR (ddPCR) method, droplet digital mitochondrial DNA measurement (ddMDM), to measure mtDNA copy number not only from cell populations but also from single cells. Our developed assay can generate data in as little as 3 h, is optimized for 96-well plates, and also allows the direct use of cell lysates without the need for DNA purification or nuclear reference genes. We show that ddMDM is able to detect differences between samples whose mtDNA copy number was close enough as to be indistinguishable by other commonly used mtDNA quantitation methods. By utilizing ddMDM, we show quantitative changes in mtDNA content per cell across a wide variety of physiological contexts including cancer progression, cell cycle progression, human T cell activation, and human aging.

Biological Frailty Index in centenarians.

This study measured the subclinical frailty of centenarians by looking at the accumulation of their biological abnormalities. For this aim, a biological Frailty Index (FI) was computed in centenarians living in Northern Italy. The median value of the biological FI was 0.33 (interquartile range, IQR 0.28-0.41). The biological FI did not significantly differ between women (0.34, IQR 0.31-0.39) and men (0.32, IQR 0.26-0.43). The biological FI seems to have a narrower distribution compared to clinical FI we previously computed in the same cohort. In conclusion, our study suggests that centenarians benefit from exceptional biological reserves that might be underestimated by clinical appearances.

Socially desirable responding in geriatric outpatients with and without mild cognitive impairment and its association with the assessment of self-reported mental health.

BACKGROUND: Socially desirable responding is a potentially relevant issue in older adults and can be evaluated with the Marlowe-Crowne Social Desirability Scale (MCSDS). However, the eight-item MCSDS has never been specifically administered to geriatric subjects, and there is a dearth of literature on the relationship between social desirability and cognitive impairment. Also, the connection between social desirability and subjective measures of psychological well-being is a matter of controversy. This study has three main aims. First, to determine the psychometric properties of the eight-item MCSDS in geriatric outpatients without dementia (i.e. with normal cognition (NC) or mild cognitive impairment (MCI)). Second, to investigate the link between social desirability and cognitive functioning. Third, to determine the association between social desirability and the assessment of self-reported mental health. METHODS: Community-dwelling outpatients (aged ≥ 65) were consecutively recruited and neuropsychologically tested to diagnose NC or MCI (n = 299). Social desirability was assessed with the eight-item MCSDS. Depressive and anxiety symptoms were measured with the short Geriatric Depression (GDS-s) and the State-Trait Personality Inventory Trait Anxiety (STPI-TA) scales. RESULTS: On principal components analysis, the eight-item MCSDS was found to have a multidimensional structure. Of the initial three-component solution, only two subscales had acceptable internal consistency (Cronbach's alpha > 0.6): "Acceptance of responsibility" and "Integrity". The third subscale ("Kindness towards others") appeared to gauge two distinct constructs of formal (i.e. politeness) versus substantive (i.e. forgiveness) compassion. On binary logistic regression, only higher income was a significant predictor of formal compassion. Test-retest reliability was substantial to excellent (Gwet's AC2 ≥ 0.8). There were no meaningful differences in social desirability between the NC and MCI groups. Likewise, negative Spearman's correlations between social desirability and cognitive Z-scores across the whole sample were weak (rs < |0.3|) and confined to one MCSDS item. Although social desirability was an independent predictor of the STPI-TA score in multiple linear regression, it explained only a marginal amount of incremental variance in anxiety symptoms (less than 2%). CONCLUSIONS: Our results suggest that social desirability need not be a major concern when using questionnaires to assess mental health in geriatric outpatients without dementia.

Genomic history of the Italian population recapitulates key evolutionary dynamics of both Continental and Southern Europeans.

BACKGROUND: The cline of human genetic diversity observable across Europe is recapitulated at a micro-geographic scale by variation within the Italian population. Besides resulting from extensive gene flow, this might be ascribable also to local adaptations to diverse ecological contexts evolved by people who anciently spread along the Italian Peninsula. Dissecting the evolutionary history of the ancestors of present-day Italians may thus improve the understanding of demographic and biological processes that contributed to shape the gene pool of European populations. However, previous SNP array-based studies failed to investigate the full spectrum of Italian variation, generally neglecting low-frequency genetic variants and examining a limited set of small effect size alleles, which may represent important determinants of population structure and complex adaptive traits. To overcome these issues, we analyzed 38 high-coverage whole-genome sequences representative of population clusters at the opposite ends of the cline of Italian variation, along with a large panel of modern and ancient Euro-Mediterranean genomes. RESULTS: We provided evidence for the early divergence of Italian groups dating back to the Late Glacial and for Neolithic and distinct Bronze Age migrations having further differentiated their gene pools. We inferred adaptive evolution at insulin-related loci in people from Italian regions with a temperate climate, while possible adaptations to pathogens and ultraviolet radiation were observed in Mediterranean Italians. Some of these adaptive events may also have secondarily modulated population disease or longevity predisposition. CONCLUSIONS: We disentangled the contribution of multiple migratory and adaptive events in shaping the heterogeneous Italian genomic background, which exemplify population dynamics and gene-environment interactions that played significant roles also in the formation of the Continental and Southern European genomic landscapes.

Novel Insight in Idiopathic Normal Pressure Hydrocephalus (iNPH) Biomarker Discovery in CSF.

Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible neurological disease, causing motor and cognitive dysfunction and dementia. iNPH and Alzheimer's disease (AD) share similar molecular characteristics, including amyloid deposition, t-tau and p-tau dysregulation; however, the disease is under-diagnosed and under-treated. The aim was to identify a panel of sphingolipids and proteins in CSF to diagnose iNPH at onset compared to aged subjects with cognitive integrity (C) and AD patients by adopting multiple reaction monitoring mass spectrometry (MRM-MS) for sphingolipid quantitative assessment and advanced high-resolution liquid chromatography-tandem mass spectrometry (LC-MS/MS) for proteomic analysis. The results indicated that iNPH are characterized by an increase in very long chains Cer C22:0, Cer C24:0 and Cer C24:1 and of acute-phase proteins, immunoglobulins and complement component fragments. Proteins involved in synaptic signaling, axogenesis, including BACE1, APP, SEZ6L and SEZ6L2; secretory proteins (CHGA, SCG3 and VGF); glycosylation proteins (POMGNT1 and DAG1); and proteins involved in lipid metabolism (APOH and LCAT) were statistically lower in iNPH. In conclusion, at the disease onset, several factors contribute to maintaining cell homeostasis, and the protective role of very long chains sphingolipids counteract overexpression of amyloidogenic and neurotoxic proteins. Monitoring specific very long chain Cers will improve the early diagnosis and can promote patient follow-up.

Different dimensions of social support differentially predict psychological well-being in late life: opposite effects of perceived emotional support and marital status on symptoms of anxiety and of depression in older outpatients in Italy.

BACKGROUND: Social support is important to psychological well-being in late life. However, findings in the literature regarding its effects are mixed, less information is available for anxiety than for depressive symptoms, and few studies have been carried out in Italy. Therefore, the aim of this study was to investigate the influence of social support on symptoms of anxiety and of depression in a sample of geriatric outpatients in Italy. METHODS: This cross-sectional study consecutively enrolled 299 outpatients without dementia (age ≥ 65, all neuropsychologically tested). Social support was assessed with the ENRICHD Social Support Instrument and by interview. Symptoms of anxiety and of depression were evaluated with short versions of the State-Trait Personality Inventory Trait Anxiety and Geriatric Depression scales. The relationship between social support and psychological well-being was examined by multiple linear regression models with socio-demographic and clinical variables, including cognitive performance, as potential confounders. RESULTS: Perceived emotional support was a negative predictor of symptoms of anxiety (standardised beta coefficient (ß) -0.288, standard error (SE) 0.074, P < 0.001) and symptoms of depression (ß -0.196, SE 0.040, P < 0.001). On the contrary, marital status (i.e. being married) was a positive predictor of symptoms of anxiety (ß 0.199, SE 0.728, P = 0.003) and symptoms of depression (ß 0.142, SE 0.384, P = 0.035). CONCLUSIONS: Different dimensions of social support differentially affect psychological well-being. The protective effect of perceived emotional support is consistent with social cognitive models of health. The harmful effect of being married may be capturing the distress of the pre-bereavement period. Alternatively, it may reflect oppression by gender roles within marriage in a predominantly female sample in a traditional society. Our findings provide insight into the relationship between social support and psychological well-being, and identify potential targets for psychosocial interventions promoting mental health in late life.

Socio-demographic characteristics and cognitive performance in oldest old subjects asking for driving license renewal.

BACKGROUND: No papers have examined the relationship between socio-demographic characteristics and cognitive performance in oldest old subjects (i.e, > = 80 years old) asking for driving license renewal. We hypothesize that, even in this highly functioning population, age, sex, and education influence cognitive performance, expressed as total or single domain (raw) test scores. This research question allows to describe, identify, and preserve independence of subjects still able to drive safely. METHODS: We examined cross-sectionally a cohort of > = 80 years old subjects (at enrollment) asking for driving license renewal in the Milan area, Italy, 2011-2017. The analysis was restricted to 3378 first and 863 second visits where individual's cognitive performance was evaluated. According to the study protocol, the Mini Mental State Examination (MMSE) test was administered at the first visit for driving license renewal and the Montreal Cognitive Assessment (MoCA) test at the second visit, following an additional renewal request. Ordinary least squares regression models were fitted at either time points. In each model, we included age, sex, and education as independent variables, whereas the dependent variable was total or single domain score for either test. In total, we fitted 15 regression models to assess our research hypothesis. RESULTS: The median subject in our sample reached the maximum scores on domains targeting operational and tactical abilities implied in safe driving, but had sub-optimal scores in the long-term memory domain included among the strategic abilities. In multiple models, being > = 87 (versus 80- < 86 years old) significantly decreased the mean total and memory scores of MMSE, but not those of the MoCA. Females (versus males) had significantly higher mean total and long-term memory scores of either tests, but not other domains. Mean total and single domain scores increased for increasing education levels for either tests, with increments for high school graduates being ~ 2 of those with (at most) a junior high school diploma. CONCLUSIONS: Sex and education, as well as age to a lesser extent, predict cognitive functioning in our oldest old population, thus confirming that concepts like cognitive reserve and successful ageing are valuable constructs in the identification of older subjects still able to drive.

Can Serum Nitrosoproteome Predict Longevity of Aged Women?

Aging is characterized by increase in reactive oxygen (ROS) and nitrogen (RNS) species, key factors of cardiac failure and disuse-induced muscle atrophy. This study focused on serum nitroproteome as a trait of longevity by adopting two complementary gel-based techniques: two-dimensional differential in gel electrophoresis (2-D DIGE) and Nitro-DIGE coupled with mass spectrometry of albumin-depleted serum of aged (A, n = 15) and centenarian (C, n = 15) versus young females (Y, n = 15). Results indicate spots differently expressed in A and C compared to Y and spots changed in A vs. C. Nitro-DIGE revealed nitrosated protein spots in A and C compared to Y and spots changed in A vs. C only (p-value < 0.01). Nitro-proteoforms of alpha-1-antitripsin (SERPINA1), alpha-1-antichimotripsin (SERPINA3), ceruloplasmin (CP), 13 proteoforms of haptoglobin (HP), and inactive glycosyltransferase 25 family member 3 (CERCAM) increased in A vs. Y and C. Conversely, nitrosation levels decreased in C vs. Y and A, for immunoglobulin light chain 1 (IGLC1), serotransferrin (TF), transthyretin (TTR), and vitamin D-binding protein (VDBP). Immunoblottings of alcohol dehydrogenase 5/S-nitrosoglutathione reductase (ADH5/GSNOR) and thioredoxin reductase 1 (TRXR1) indicated lower levels of ADH5 in A vs. Y and C, whereas TRXR1 decreased in A and C in comparison to Y. In conclusion, the study identified putative markers in C of healthy aging and high levels of ADH5/GSNOR that can sustain the denitrosylase activity, promoting longevity.

Validation study of the Italian version of Communication Activities of the Daily Living (CADL 2) as an ecologic cognitive assessment measure in older subjects.

INTRODUCTION: Communication can be affected by age related cognitive decline and mental deterioration. The second edition of the Communication Activities of the Daily Living (CADL 2) appears as an interesting ecological assessment tool of cognitive functions in old age. OBJECTIVE: The aim of this work is to (1) develop an Italian version of CADL 2, (2) to test its psychometric properties in terms of reliability and validity, and (3) to measure CADL 2 discriminative capacity between cognitively healthy and cognitively impaired older subjects. METHOD: One hundred and eleven subjects were enrolled (36 M; 75 F, age 80, 80.85 ± 7 years, education 9.3 ± 4.7 years). The CADL 2 was administered together with a standard neuropsychological battery. RESULTS: The CADL 2 showed good reliability and correlates with all the cognitive evaluation tests. The CADL 2's area under the curve was equal to 0.80, index of good diagnostic accuracy. CONCLUSIONS: The CADL 2 is an appropriate assessment tool for communication skills in aging.

Adapted physical activity to promote active and healthy ageing: the PoliFIT pilot randomized waiting list-controlled trial.

BACKGROUND: Physical activities can prevent disability in elderly. AIMS: To evaluate the feasibility and impact on physical function of an adapted physical activity (APA) programme in community-dwelling people of ≥ 70 years old. METHODS: Non-blinded randomized trial with a waiting list control. Eligible people (n = 186) were randomly allocated to 4 months of weekly APA classes of 45 min or in control group performing usual lifestyle activity. PRIMARY OUTCOME: time to walk 400 m. SECONDARY OUTCOMES: short physical performance battery (SPPB), pain (visual analogic scale, McGill Questionnaire), Oswestry Disability Index (ODI), Geriatric Depression Scale (GDS), handgrip strength, accesses to Emergency Department and falls. RESULTS: Participants were allocated to the intervention (n = 130) or to the control (n = 56) group (80% females aged 75.6 ± 4.6 years). We found statistically significant difference in the time to walk 400 m only in the subgroup intervention with the lower performance at baseline (p for interaction 0.031). SPPB improved and VAS decreased more in the intervention group. No significant differences for McGill questionnaire, ODI, GDS, accesses to ER and falls were showed. DISCUSSION: Despite the good rate of attendance (71%) and satisfaction (97%), our APA programme was associated with no benefit on the time to walk 400 m and small benefit on SPPB and VAS. The efficacy of the intervention was likely limited by the short duration and low intensity and by the already good performance of our population at baseline. CONCLUSIONS: We designed this initiative as a pilot study intending to implement research of this type in the future.

Evaluation of Lymphocyte Response to the Induced Oxidative Stress in a Cohort of Ageing Subjects, including Semisupercentenarians and Their Offspring.

The production of reactive oxygen species (ROS) may promote immunosenescence if not counterbalanced by the antioxidant systems. Cell membranes, proteins, and nucleic acids become the target of ROS and progressively lose their structure and functions. This process could lead to an impairment of the immune response. However, little is known about the capability of the immune cells of elderly individuals to dynamically counteract the oxidative stress. Here, the response of the main lymphocyte subsets to the induced oxidative stress in semisupercentenarians (CENT), their offspring (OFF), elderly controls (CTRL), and young individuals (YO) was analyzed using flow cytometry. The results showed that the ratio of the ROS levels between the induced and noninduced (I/NI) oxidative stress conditions was higher in CTRL and OFF than in CENT and YO, in almost all T, B, and NK subsets. Moreover, the ratio of reduced glutathione levels between I/NI conditions was higher in OFF and CENT compared to the other groups in almost all the subsets. Finally, we observed significant correlations between the response to the induced oxidative stress and the degree of methylation in specific genes on the oxidative stress pathway. Globally, these data suggest that the capability to buffer dynamic changes in the oxidative environment could be a hallmark of longevity in humans.

Genome-Wide Scan Informed by Age-Related Disease Identifies Loci for Exceptional Human Longevity.

We developed a new statistical framework to find genetic variants associated with extreme longevity. The method, informed GWAS (iGWAS), takes advantage of knowledge from large studies of age-related disease in order to narrow the search for SNPs associated with longevity. To gain support for our approach, we first show there is an overlap between loci involved in disease and loci associated with extreme longevity. These results indicate that several disease variants may be depleted in centenarians versus the general population. Next, we used iGWAS to harness information from 14 meta-analyses of disease and trait GWAS to identify longevity loci in two studies of long-lived humans. In a standard GWAS analysis, only one locus in these studies is significant (APOE/TOMM40) when controlling the false discovery rate (FDR) at 10%. With iGWAS, we identify eight genetic loci to associate significantly with exceptional human longevity at FDR < 10%. We followed up the eight lead SNPs in independent cohorts, and found replication evidence of four loci and suggestive evidence for one more with exceptional longevity. The loci that replicated (FDR < 5%) included APOE/TOMM40 (associated with Alzheimer's disease), CDKN2B/ANRIL (implicated in the regulation of cellular senescence), ABO (tags the O blood group), and SH2B3/ATXN2 (a signaling gene that extends lifespan in Drosophila and a gene involved in neurological disease). Our results implicate new loci in longevity and reveal a genetic overlap between longevity and age-related diseases and traits, including coronary artery disease and Alzheimer's disease. iGWAS provides a new analytical strategy for uncovering SNPs that influence extreme longevity, and can be applied more broadly to boost power in other studies of complex phenotypes.

Spontaneous confabulations in amnestic-mild cognitive impairment due to Alzheimer's disease: a new (yet old) atypical variant?

Confabulation may be present in Alzheimer's disease (AD), but usually it is not a primary feature of either its typical or atypical variants. In this report, we describe the case of an AD patient who showed an unusual and enduring neuropsychiatric phenotype characterized by early and prominent spontaneous confabulation. Surprisingly, such atypical AD presentation bears a striking resemblance to presbyophrenia, a subtype of dementia which was described at the beginning of the twentieth century and then sank into oblivion. In discussion, we speculate on the "return" of presbyophrenia as an unrecognized neuropsychiatric variant of AD and its possible neuroanatomical substrates.

Duloxetine in elderly major depression disorder: effectiveness and drug plasma level evaluation.

OBJECTIVE: The aim of this open-label naturalistic study was to assess clinical outcomes and the predictive value of duloxetine plasma levels in major depressive disorder in the elderly. METHODS: This naturalistic, open-label design involved 35 outpatients aged between 65 and 87 years. Duloxetine plasma levels were collected in 24 patients after the first month. Patients were evaluated using 21-item Hamilton Rating Scales for Depression, Hamilton Rating Scales for Anxiety, the Clinical Global Impression Severity, Mini Mental State Examination, Cumulative Illness Rating Scale, Barthel Index and Beck's Depression Inventory. RESULTS: Duloxetine plasma levels at T2 ranged from 4.9 to 201.9 ng/mL without a significant correlation between duloxetine dose and plasma levels. A significant improvement in mean 21-item Hamilton Rating Scales for Depression total scores at T2,T3, T4, T9 and T12 and a progressive significantly decrease of the mean Hamilton Rating Scales for Anxiety scores from T3 to T12 were observed. CONCLUSIONS: The levels of duloxetine in plasma do not correlate with a greater clinical improvement, indeed appear to adversely affect the improvement of the Beck Depression Inventory and Hamilton Rating Scales for Anxiety. This could be explained by an increase in side effects that may aggravate the discomfort felt by the patient. Copyright © 2016 John Wiley & Sons, Ltd.

Pneumococcal colonization in older adults.

BACKGROUND: Little is known about pneumococcal carrier states in older adults. The main aim of this study was to evaluate pneumococcal colonization patterns among older adults in two centres in Milan, Italy, before the widespread use of the 13-valent pneumococcal vaccine (PCV13) in this age group, to investigate demographic and clinical features that are associated with pneumococcal colonization and to estimate the potential coverage offered by PCV13. RESULTS: Among 417 adults ≥65 years old (171, 41.1 %, ≥75 years), 41 (9.8 %) were pneumococcal carriers. Univariate and multivariate analyses revealed that pneumococcal colonization was significantly less common among individuals with underlying co-morbidities than among those without (odds ratio [OR] 0.453, 95 % confidence interval [CI] 0.235-0.875, p = 0.018; adjusted OR 0.503, 95 % CI 0.255-0.992, p = 0.047). Moreover, among these patients, those with cardiac disease had a significantly lower risk of colonization (OR 0.308, 95 % CI 0.119-0.795, p = 0.015; adjusted OR 0.341, 95 % CI 0.13-0.894, p = 0.029). Only one vaccinated subject who received 23-valent polysaccharide pneumococcal vaccine (PPV23) was colonized. Twenty-five (89.3 %) of the subjects who were <75 years old and 9 (75.0 %) of those who were ≥75 years old were colonized by at least one of the serotypes that is included in PCV13, with serotype 19 F being the most common. Respiratory allergies as well as overall co-morbidities were more common in subjects who were positive for only non-PCV13 serotypes compared with negative subjects and those who were carriers of only PCV13 serotypes. CONCLUSIONS: Although this study included a relatively small number of subjects and has been performed in a limited geographic setting, results showed that pneumococcal colonization in older people is common, and the monitoring of carriers can offer useful information about the circulation of this pathogen among older people and the potential protective effect of pneumococcal vaccines. Because the colonization in most cases involves the strains that are included in PCV13, this vaccine could be useful in the prevention of pneumococcal infections in the overall population of older people. In subjects with respiratory allergies and in those with co-morbidities, the addition of the PPV23 to PCV13 should be recommended. Due to the low vaccination coverage, urgent educational programmes are required to inform older adults and their medical doctors of the risks of pneumococcal infection and the efficacy and safety of the available pneumococcal vaccines.

Familial late-onset Alzheimer's disease: description of an Italian family with four affected siblings and one case of early-onset dementia in the preceding generation.

We describe a family composed of six siblings, four of which affected by late-onset Alzheimer's disease (LOAD). We constructed the family pedigree, evaluated mutations usually associated with early-onset Alzheimer's disease (APP, PSEN1, PSEN2), and assessed polymorphisms in the apolipoprotein E (APOE) gene and in cytokine genes that we had previously found to be associated with a higher risk of LOAD (IL-10, IL-6, TNF-α). Results showed that all subjects carried one ε4 allele of the APOE gene and those with the earliest age of onset exhibited the AA (-1082) IL-10 and the CC (-174) IL-6 genotypes. The only male had a genetic profile which also included the A (-308) TNF-α allele. These data confirm the role of the APOE gene as genetic risk factor in LOAD, and suggest that the risk of developing AD may be governed by a "susceptibility profile" involving polymorphisms in inflammatory genes.

Type I interferon-mediated pathway interacts with peroxisome proliferator activated receptor-γ (PPAR-γ): at the cross-road of pancreatic cancer cell proliferation.

Pancreatic adenocarcinoma remains an unresolved therapeutic challenge because of its intrinsically refractoriness to both chemo- and radiotherapy due to the complexity of signaling and the activation of survival pathways in cancer cells. Recent studies have demonstrated that the combination of some drugs, targeting most of aberrant pathways crucial for the survival of pancreatic cancer cells may be a valid antitumor strategy for this cancer. Type I interferons (IFNs) may have a role in the pathogenesis and progression of pancreatic adenocarcinoma, but the limit of their clinical use is due to the activation of tumor resistance mechanisms, including JAK-2/STAT-3 pathway. Moreover, aberrant constitutive activation of STAT-3 proteins has been frequently detected in pancreatic adenocarcinoma. The selective targeting of these cell survival cascades could be a promising strategy in order to enhance the antitumor effects of type I IFNs. The activation of peroxisome proliferator-activated receptor γ (PPAR-γ), on the other hand, has a suppressive activity on STAT-3. In fact, PPAR-γ agonists negatively modulate STAT-3 through direct and/or indirect mechanisms in several normal and cancer models. This review provides an overview on the current knowledge about the molecular mechanisms and antitumor activity of these two promising classes of drugs for pancreatic cancer therapy. Finally, the synergistic antiproliferative activity of combined IFN-ß and troglitazone treatment on pancreatic cancer cell lines, evaluated in vitro, and the consequent potential clinical applications will be discussed.

Global changes in DNA methylation in Alzheimer's disease peripheral blood mononuclear cells.

Changes in epigenetic marks may help explain the late onset of Alzheimer's disease (AD). In this study we measured genome-wide DNA methylation by luminometric methylation assay, a quantitative measurement of genome-wide DNA methylation, on DNA isolated from peripheral blood mononuclear cells of 37 subjects with late-onset AD (LOAD) and 44 healthy controls (CT). We found an increase in global DNA methylation in LOAD subjects compared to CT (p=0.0122), associated with worse cognitive performances (p=0.0002). DNA hypermethylation in LOAD group was paralleled by higher DNA methyltransferase 1 (DNMT1) gene expression and protein levels. When data were stratified on the basis of the APOE polymorphisms, higher DNA methylation levels were associated with the presence of APOE ε4 allele (p=0.0043) in the global population. Among the APOE ε3 carriers, a significant increase of DNA methylation was still observed in LOAD patients compared to healthy controls (p=0.05). Our data suggest global DNA methylation in peripheral samples as a useful marker for screening individuals at risk of developing AD.