Investigation of hallmarks of carbonyl stress and formation of end products in feline chronic kidney disease as markers of uraemic toxins.

OBJECTIVES: Cats are commonly affected by chronic kidney disease (CKD). Many reactive carbonyl intermediates and end products originating from the oxidative stress pathways are recognised as uraemic toxins and may play a role in CKD progression. The aim of the present study is to confirm whether carbonyl end-product formation is higher in cats affected by CKD and to assess whether an angiotensin-converting enzyme inhibitor (ACEi) might affect these hallmarks. METHODS: Twenty-two cats were divided into three groups: a control group (CG), cats with CKD and cats with CKD treated with an ACEi. Serum levels of pentosidine, carboxymethyllysine, advanced oxidation protein products, malondialdehyde, methylglyoxal and hexanoyl-lysine were measured. In addition, biochemical parameters and systolic blood pressure were evaluated. After checking for normality, comparisons between groups were performed followed by multiple comparison tests. P values ⩽0.05 were considered significant. Correlations between concentrations of the considered biomarkers and of the other metabolic parameters were investigated. RESULTS: Advanced oxidation protein products, malondialdehyde and hexanoyl-lysine concentrations were significantly higher in CKD and ACEi-treated groups compared with the CG ( P <0.05). Carboxymethyllysine increased in the ACEi-treated group when compared with the CG, whereas intermediate values of these biomarkers were found in the CKD group ( P <0.05). The ACEi-treated group showed the highest values of carboxymethyllysine, advanced oxidation protein products and hexanoyl-lysine. By contrast, the CKD group had the highest concentration of malondialdehyde. No statistically significant difference was found in the levels of pentosidine or methylglyoxal. End products correlated with creatinine and urea and with each other. CONCLUSIONS AND RELEVANCE: Significantly high concentrations of both intermediate and end products of carbonyl/oxidative stress were detected in CKD cats. This is the first study to have concurrently taken into account several uraemic toxins and biochemical parameters in cats affected by CKD.

Pectin-honey hydrogel: Characterization, antimicrobial activity and biocompatibility.

BACKGROUND: Novel pectin-honey hydrogels have been developed and characterized as medical device. Ideally, a wound dressing should maintain optimal fluid affinity, permit moisture evaporation, protect the wound from microbes, and have shape-conformability, biocompatibility, and antibacterial activity. OBJECTIVE: A novel, simple and fast method to produce pectin-honey wound dressings is described. METHODS: The properties of these pectin-honey hydrogels were investigated, including swelling ability, water vapour transmission rate, hydrogen peroxide production, methylglyoxal content and antibacterial activity. Biocompatibility was assessed by proliferation assays using cultured fibroblast cells and by in vivo study with subcutaneous and intraperitoneal implantation in rats. RESULTS: Hydrogel showed a good water vapour transmission rate, fluid uptake and were not cytotoxic for fibroblasts. The hydrogel demonstrated good antibacterial activity toward clinically relevant pathogens, including S. aureus and E. coli. Biocompatibility was confirmed by the measurement of plasma levels of interleukin (IL)1 beta, IL-6, tumour necrosis factor (TNF) alpha, and prostaglandin (PG)E2. No histological changes were observed. CONCLUSIONS: The presence of a natural active component, conformability, and complete resorbability are the main characteristics of this new biocompatible biomaterial that is well tolerated by the body, possibly improves healing, may be used for surgical complications prevention, with a simple and inexpensive production process.

Vitamin C, Aging and Alzheimer's Disease.

Accumulating evidence in mice models of accelerated senescence indicates a rescuing role of ascorbic acid in premature aging. Supplementation of ascorbic acid appeared to halt cell growth, oxidative stress, telomere attrition, disorganization of chromatin, and excessive secretion of inflammatory factors, and extend lifespan. Interestingly, ascorbic acid (AA) was also found to positively modulate inflamm-aging and immunosenescence, two hallmarks of biological aging. Moreover, ascorbic acid has been shown to epigenetically regulate genome integrity and stability, indicating a key role of targeted nutrition in healthy aging. Growing in vivo evidence supports the role of ascorbic acid in ameliorating factors linked to Alzheimer's disease (AD) pathogenesis, although evidence in humans yielded equivocal results. The neuroprotective role of ascorbic acid not only relies on the general free radical trapping, but also on the suppression of pro-inflammatory genes, mitigating neuroinflammation, on the chelation of iron, copper, and zinc, and on the suppression of amyloid-beta peptide (Aß) fibrillogenesis. Epidemiological evidence linking diet, one of the most important modifiable lifestyle factors, and risk of Alzheimer's disease is rapidly increasing. Thus, dietary interventions, as a way to epigenetically modulate the human genome, may play a role in the prevention of AD. The present review is aimed at providing an up to date overview of the main biological mechanisms that are associated with ascorbic acid supplementation/bioavailability in the process of aging and Alzheimer's disease. In addition, we will address new fields of research and future directions.

Evaluation of prognostic indices in elderly hospitalized patients.

AIM: Prognosis informs the physician's decision-making process, especially for frail older adults. So far, any non-disease-specific index has proven full evidence for routine use in clinical practice. Here, we aimed at assessing, prospectively, the calibration and discriminating accuracy of validated prognostic indices in a cohort of elderly hospitalized patients. METHODS: This was a prospective observational study that enrolled elderly patients (n = 100). The patients' assessment included clinical variables, as well as the following five prognostic indices of mortality: (i) Levine index (2007); (ii) Walter index (2001); (iii) CARING (C, primary diagnosis of cancer; A, ≥ 2 admissions to the hospital for a chronic illness within the last year; R, resident in a nursing home; I, intensive care unit admission with multiorgan failure, NG, noncancer hospice guidelines [meeting ≥ 2 of the National Hospice and Palliative Care Organization's guidelines]) criteria of Fischer (2006-2011); (iv) Silver Code of Di Bari (2010); and (v) Burden of Illness Score for Elderly Persons of Inouye (2003). RESULTS: Patients' clinical characteristics: 70% women (age 86.20 ± 0.69 years), 30% men (age 85.40 ± 1.07 years), Comorbidity Illness rating scale (CIRS) 4.3 ± 0.61 and Barthel Index 28 ± 0.54. Walter and Burden of Illness Score for Elderly Persons scores showed similar prediction rates when compared with the expected validated values (ancova: F = 14.00, P < 0.008). Burden of Illness Score for Elderly Persons was the most calibrated and accurate index (receiver operating characteristic curve 0.72; P < 0.02). CONCLUSIONS: None of the assessed prognostic indices, in a "real world" scenario, afforded the optimal predictive accuracy (receiver operating characteristic curve 0.90); all these indices are still far from a robust answer to the prognosis in older age, reflecting a poor ability to encompass the spectrum of frailty. Effort should be made to tailor the prognostication in geriatrics, moving from a disease-centered model to a precision model, tailored to the frail phenotype. Geriatr Gerontol Int 2017; 17: 1015-1021.

Do Cancer Drugs Counteract Neurodegeneration? Repurposing for Alzheimer's Disease.

In spite of in depth investigations in the field of the amyloid cascade hypothesis, so far, no disease modifying therapy has been developed for Alzheimer's disease (AD). The pathophysiology provides some evidence of the inverse correlation between cancer and AD. Both AD and cancer are characterized by abnormal cellular behaviors; trigger factors along with a meta synchronously action is expected to drive cancer or neurodegeneration, supporting, respectively, progressive neuronal loss or uncontrolled cell proliferation in cancer cells. So far, cancer and AD are seemingly two opposite ends of the same biological spectrum. Basic science increasingly indicates shared molecular mechanisms between cancer and AD and gives weight to key relevant biological theories; according to them, the inverse tuning of clustered gene expression, the sharing of mutual independent pathway or the deregulated unfolded proteins system (UPR) may count for this inverse association. Additionally, the common biological background gave credibility to the recent discovery of a repurposing role for cancer drugs in AD. It refers to the development of new uses for existing pharmaceuticals having the same role as the original mechanism or to the discovery of a new drug action with disease modifying effects. The present review summarizes the most important biological theories that link neurodegeneration and cancer and provides an up-to-date revision of the repurposing cancer agents for AD. The review also addresses the gap of knowledge, since drug cancer repositioning holds an important promise but further investigations are warranted to ascertain the clinical relevance of such attractive clinical candidate compounds for AD.

Beta-amyloid 1-42 monomers, but not oligomers, produce PHF-like conformation of Tau protein.

The mechanistic relationship between amyloid ß1-42 (Aß1-42) and the alteration of Tau protein are debated. We investigated the effect of Aß1-42 monomers and oligomers on Tau, using mice expressing wild-type human Tau that do not spontaneously develop Tau pathology. After intraventricular injection of Aß1-42, mice were sacrificed after 3 h or 4 days. The short-lasting treatment with Aß monomers, but not oligomers, showed a conformational PHF-like change of Tau, together with hyperphosphorylation. The same treatment induced increase in concentration of GSK3 and MAP kinases. The inhibition of the kinases rescued the Tau changes. Aß monomers increased the levels of total Tau, through the inhibition of proteasomal degradation. Aß oligomers reproduced all the aforementioned alterations only after 4 days of treatment. It is known that Aß1-42 monomers foster synaptic activity. Our results suggest that Aß monomers physiologically favor Tau activity and dendritic sprouting, whereas their excess causes Tau pathology. Moreover, our study indicates that anti-Aß therapies should be targeted to Aß1-42 monomers too.

Amnestic mild cognitive impairment and conversion to Alzheimer's disease: insulin resistance and glycoxidation as early biomarker clusters.

Autopsy studies have indicated brain accumulation of amyloid-ß peptides as a common pathogenetic hallmark of amnestic cognitive impairment (aMCI) and overt Alzheimer's disease (AD). The pathogenesis of AD is still debated but recent reports have even designated AD as type III diabetes. This study aims to assess plasma levels of malondialdehyde, pentosidine, and insulin resistance in a group of aMCI patients, AD subjects, and age- and gender-matched controls, to confirm, beyond the accumulation of amyloid-ß, the presence of a metabolic disorder, as a causative/contributive factor for AD. Patients were recruited and diagnosed as aMCI (n = 180), AD (n = 84), and age- and gender-matched controls (n = 62) at three different Italian memory clinics. Plasma insulin and glucose, plasma pentosidine and malondialdehyde (MDA), HOMA-IR and QUICKI score for insulin sensitivities indexes were collected at the basal visit. Plasma MDA levels were higher in the aMCI group who converted to AD compared to controls, stable aMCI subjects, and AD subjects (p < 0.01) respectively, while plasma pentosidine was higher compared to controls. The aMCI group showed a significant correlation between HOMA-IR, QUICKI, insulin, and MDA (p < 0.02). aMCI might be considered the early biochemical active disease stage where glycoxidation, hyperinsulinemia, and pro-amyloidogenic status are at the highest rate while overt AD might indicate the glycoxidative cascade dwindling, ending a process possibly started two decades earlier.

Monomeric Aß1-42 and RAGE: key players in neuronal differentiation.

The aggregation of amyloid-ß (Aß) peptides plays a crucial role in the onset and progression of Alzheimer's disease. Monomeric form of Aß, indeed, could exert a physiological role. Considering the anti-oligomerization property of all-trans retinoic acid (ATRA), the involvement of monomeric Aß1-42 in ATRA-induced neuronal differentiation has been investigated. Four-day ATRA treatment increases ß-secretase 1 (BACE1) level, Aß1-42 production, and receptor for advanced glycation end-products (RAGE) expression. RAGE is a well-recognized receptor for Aß, and the block of both RAGE and Aß1-42 with specific antibodies strongly impairs neurite formation in ATRA-treated cells. The involvement of Aß1-42 and RAGE in ATRA-induced morphologic changes has been confirmed treating undifferentiated cells with different molecular assemblies of peptide: 1 µM monomeric, but not oligomeric, Aß1-42 increases RAGE expression and favors neurite elongation. The block of RAGE completely prevents this effect. Furthermore, our data underline the involvement of the RAGE-dependent adhesion molecule amphoterin-induced gene and open reading frame-1 as downstream effector of both ATRA and Aß1-42. In conclusion, our findings identify a novel physiological role for monomeric Aß1-42 and RAGE in neuronal differentiation.

Pentosidine determination in CSF: a potential biomarker of Alzheimer's disease?

BACKGROUND: The histopathological hallmarks in Alzheimer's disease (AD) include neuronal cell death, formation of amyloid plaques and neurofibrillary tangles. Glycoxidation plays a crucial role in AD pathogenesis, as pentosidine and Nε- carboxymethyl-lysine (CML), were detected in AD hallmarks, and in vivo cerebrospinal fluid (CSF). However, the definitive role of AGEs in the neuropathology of AD is inconclusive. The aim of this preliminary study was to assess the level of pentosidine in CSF of patients affected by neurological disorders, including probable AD, in order to assess the feasibility of AGEs detection in CSF and to explore pentosidine as a potential biomarker in AD. METHODS: Twenty-five patients diagnosed with AD (NINCDS ADRDA criteria) and different neurological disorders were enrolled. Diabetic patients were excluded. Pentosidine, CML, amyloid ß1-42 were assessed by high performance liquid chromatography (HPLC) by Odetti modified method,and by sandwich ELISA respectively. RESULTS: Our data showed the presence of pentosidine in all CSF samples, a significant increase in CSF pentosidine levels with age (p<0.05) and a significant decreased concentration of pentosidine in four AD subjects (p<0.01), after normalization to CSF protein concentration. CONCLUSIONS: The study showed that AGEs concentration in CSF might benefit from age correction, at least for pentosidine, originally addressing a potential systemic age-dependent AGEs accumulation. The significant decrease of CSF pentosidine in AD, even in 4 patients, might conceive that different AGEs inform specific types of neurodegeneration, depending on oxidative stress levels, blood - brain barrier permeability, brain localization and systemic risk factors.

Structural alterations of human serum albumin caused by glycative and oxidative stressors revealed by circular dichroism analysis.

The aim of this work was to evaluate the ability of oxidative and glycative stressors to modify properties of human serum albumin (HSA) by analyzing markers of glycation (pentosidine) and oxidation (advanced oxidative protein products (AOPPs)) and assessing fluorescence and circular dichroism. HSA was incubated for up to 21 days with ribose, ascorbic acid (AA) and diethylenetriamine pentacetate (DTPA) in various combinations in order to evaluate influences of these substances on the structure of HSA. Ribose was included as a strong glycative molecule, AA as a modulator of oxidative stress, and DTPA as an inhibitor of metal-catalyzed oxidation. Ribose induced a significant increase in pentosidine levels. AA and DTPA prevented the accumulation of pentosidine, especially at later time points. Ribose induced a mild increase in AOPP formation, while AA was a strong inducer of AOPP formation. Ribose, in combination with AA, further increased the formation of AOPP. DTPA prevented the AA-induced generation of AOPP. Ribose was also a potent inducer of fluorescence at 335nm ex/385nm em, which is typical of pentosidine. AA and DTPA prevented this fluorescence. Circular dichroism showed complex results, in which AA and DTPA were strong modifiers of the percentages of the alpha-helical structure of HSA, while ribose affected the structure of HSA only at later time points.

ß-amyloid 1-42 induces physiological transcriptional regulation of BACE1.

The pathogenesis of Alzheimer's disease (AD) is only partially understood. ß-amyloid (Aß) is physiologically generated by sequential cleavage of its precursor protein by the ß- and the γ-secretase and it is normally disposed of. In Alzheimer's disease, Aß is excessively produced or less dismissed, but the hypothesis on its physiological and pathological role are heterogeneous and often discordant. It has been described a positive feedback loop from the γ- to the ß-secretase cleavages of Aß precursor protein, which is activated by mutations of Presenilin 1 (PS1), the catalytic core of the γ-secretase. These findings show that Aß precursor protein as well the activity of the γ-secretase are required to obtain the up-regulation of ß-secretase which is induced by Presenilin 1 mutations. Then, Aß 1-42 is the Aß precursor protein derivative that up-regulates the expression of ß-secretase, and c-jun N-terminal kinase (JNK)/c-Jun and ERK1/2 are involved. Here, we describe the activation of ß-secretase and c-jun N-terminal kinase related proteins by monomeric Aß 1-42, defining the conditions that most efficiently strike the described signaling without producing toxicity. Taken together these data imply that monomeric Aß 1-42, at non-toxic concentrations and time frames, are able to induce a signaling pathway that leads to transcriptional activation of ß-secretase.

Aß1-42-mediated down-regulation of Uch-L1 is dependent on NF-κB activation and impaired BACE1 lysosomal degradation.

Amyloid-ß 1-42 accumulation is the major pathogenetic event in Alzheimer's disease (AD), believed to be responsible for synaptic dysfunction and neuronal cell death. However, the physiologic activity of Aß peptides remains elusive: Aß might not only play a toxic role, but also act as a functional signaling intermediate. We recently reported that Aß1-42 promotes BACE1 transcription through the activation of the JNK-c-jun pathway. Here, we show that the Aß1-42-mediated increase in BACE1 expression is accompanied by a decrease in ubiquitin C-terminal hydrolase L1 (Uch-L1) expression and activity in different cellular models such as neuroblastoma SH-SY5Y as well as NT(2) neuronal cells. We also found that the increase in BACE1 and the decrease in Uch-L1 are related events and depend on NF-κB pathway; thus, Aß1-42 is able to activate NF-κB pathway and the pretreatment with a pharmacological inhibitor, able to block the nuclear translocation of the transactivating unit p65, almost completely prevents both the decrease in Uch-L1 and the increase in BACE1 expression. In addition, the decrease in Uch-L1 activity interferes with the lysosomal degradation of BACE1, as demonstrated by the decrease in Cathepsin D activity and the partial accumulation of BACE1 in lysosomes after Aß1-42 treatment as well after Uch-L1 inhibition. In support of the in vitro data, we observed low protein levels of Uch-L1 associated with high protein levels of BACE1 in sporadic AD brains. Our data suggest that Uch-L1 could be an attractive target for the development of new therapeutic approaches for AD.

Amyloid-ß42 activates the expression of BACE1 through the JNK pathway.

The sequential endoproteolytic cleavages operated by the γ-secretase and the ß-secretase (BACE1) on the amyloid-ß protein precursor (AßPP) result in the production of the amyloid-ß (Aß) species, with two C-terminal variants, at residue 40 or at residue 42. Accumulation in brain tissue of small, soluble aggregates of Aß42 is the major pathogenic event of Alzheimer's disease (AD). However, the physiologic activity of Aß peptides is still elusive. Here, we show that expression of BACE1 is regulated by Aß42, which augments BACE1 gene transcription through the JNK/c-jun signaling pathway. Of note, Aß40 has much less effect on BACE1 expression. These findings unveil a positive feedback loop in which γ-secretase cleavage of AßPP releases a functionally-active peptide, Aß42, that promotes BACE1 transcription. Thus, gene expression induced by Aß42 may have implications in the neuronal dysfunction and degeneration that occurs in AD.

Dysregulation of SREBP2 induces BACE1 expression.

ß-Amyloid hyperproduction has been observed in response to alterations in neuronal intracellular cholesterol storage, efflux, and synthesis, induced in rats by a high-fat diet. It has been suggested that cholesterol homeostasis is altered in Alzheimer's disease resulting in higher ß- and γ-secretase activity. In the current study the neuronal activation status of sterol regulatory element binding protein 2 (SREBP2) as well as its involvement in ß-secretase BACE1 activity was investigated in high-fat fed rats (26% fat and 4% cholesterol for 20 weeks), and in SK-N-BE neuroblastoma cells exposed to 20 µM cholesterol. This work demonstrates that in the brain a hyperlipidic diet is able to induce a hyper-expression of BACE1 and determine an unbalance in cerebral cholesterol homeostasis so that SREBP2 is activated. In addition, we show for the first time the involvement of SREBP2 on expression of BACE1 in SK-N-BE cells exposed to high cholesterol. Although the enhanced risk of Alzheimer's disease in metabolic syndrome is related to several factors, our results suggest that SREBP2, which can be modulated by the impairment of cerebral cholesterol homeostasis, has a direct role on BACE1 expression and may be involved in Alzheimer's disease progression.

RNA polymerase III drives alternative splicing of the potassium channel-interacting protein contributing to brain complexity and neurodegeneration.

Alternative splicing generates protein isoforms that are conditionally or differentially expressed in specific tissues. The discovery of factors that control alternative splicing might clarify the molecular basis of biological and pathological processes. We found that IL1-α-dependent up-regulation of 38A, a small ribonucleic acid (RNA) polymerase III-transcribed RNA, drives the synthesis of an alternatively spliced form of the potassium channel-interacting protein (KCNIP4). The alternative KCNIP4 isoform cannot interact with the γ-secretase complex, resulting in modification of γ-secretase activity, amyloid precursor protein processing, and increased secretion of ß-amyloid enriched in the more toxic Aß x-42 species. Notably, synthesis of the variant KCNIP4 isoform is also detrimental to brain physiology, as it results in the concomitant blockade of the fast kinetics of potassium channels. This alternative splicing shift is observed at high frequency in tissue samples from Alzheimer's disease patients, suggesting that RNA polymerase III cogenes may be upstream determinants of alternative splicing that significantly contribute to homeostasis and pathogenesis in the brain.

Cholesterol and amyloid-ß: evidence for a cross-talk between astrocytes and neuronal cells.

Accumulating data supports the concept that alterations of cholesterol metabolism might influence the development of Alzheimer's disease (AD), a neurodegenerative disorder characterized by progressive accumulation of amyloid-ß (Aß) peptides in the brain. Changes in the neuronal production of Aß have been described as a function of cholesterol levels, thus suggesting a causal link between cholesterol homeostasis dysregulation and AD pathogenesis. Under physiological conditions, cholesterol uptake in the brain is efficiently prevented by the blood-brain barrier, and mature neurons are thought to rely on glial cells for their cholesterol supply. In the present study, we tested the hypothesis that Aß may serve as a signaling molecule capable of informing the astroglial network about the neuronal need for cholesterol. Collectively, our data bolster this hypothesis and demonstrate, for the first time, that Aß(42) exerts an inhibitory effect on the expression of the cholesterol transporter ABCA1 in cultured astrocytes. Accordingly, we also show that ABCA1 expression is reduced in the brain of AßPP/PS1 transgenic mice. These results provide a biological function for Aß peptides and may help to define the pathogenic relationship between cholesterol metabolism in brain and AD.

17A, a novel non-coding RNA, regulates GABA B alternative splicing and signaling in response to inflammatory stimuli and in Alzheimer disease.

Alternative splicing is a central component of human brain complexity; nonetheless, its regulatory mechanisms are still largely unclear. In this work, we describe a novel non-coding (nc) RNA (named 17A) RNA polymerase (pol) III-dependent embedded in the human G-protein-coupled receptor 51 gene (GPR51, GABA B2 receptor). The stable expression of 17A in SHSY5Y neuroblastoma cells induces the synthesis of an alternative splicing isoform that abolish GABA B2 intracellular signaling (i.e., inhibition of cAMP accumulation and activation of K(+) channels). Indeed, 17A is expressed in human brain, and we report that it is upregulated in cerebral tissues derived from Alzheimer disease patients. We demonstrate that 17A expression in neuroblastoma cells enhances the secretion of amyloid ß peptide (Aß) and the Aß x-42/Αß x-40 peptide ratio and that its synthesis is induced in response to inflammatory stimuli. These data correlate, for the first time, the activity of a novel pol III-dependent ncRNA to alternative splicing events and, possibly, to neurodegeneration induced by abnormal GABA B function. We anticipate that further analysis of pol III-dependent regulation of alternative splicing will disclose novel regulatory pathways associated to brain physiology and/or pathology.

Upregulation of presenilin 1 in brains of sporadic, late-onset Alzheimer's disease.

The activity of the ß-secretase involved in the cleavage of amyloid-ß (Aß) is increased in sporadic late-onset Alzheimer's disease (AD). Whether the corresponding γ-secretase activity is altered is still uncertain. We evaluated mRNA expression and protein levels of presenilin 1 (PS1) and γ-secretase activity in the frontal cortex of 32 cases with late-onset sporadic AD and those of 29 control subjects. We found a significant increase in PS1 mRNA, protein levels and γ-secretase activity in AD cases. These findings suggest that upregulation of PS1 leads to Aß overproduction and accumulation in sporadic AD.

Elevation of {beta}-amyloid 1-42 autoantibodies in the blood of amnestic patients with mild cognitive impairment.

OBJECTIVE: To develop a blood-based test for screening populations at risk for Alzheimer disease. DESIGN: Case-control study. Subjects A total of 180 patients with mild cognitive impairment (MCI) and 105 age-matched, cognitively normal controls. INTERVENTIONS: The titer of beta-amyloid 1-42 autoantibodies in the plasma was obtained at the time of diagnosis and evaluated by enzyme-linked immunosorbent assay before and after dissociation of the antigen-antibody complexes. A total of 107 patients with MCI were followed up for 36 months; 70 of the 107 cases progressed to Alzheimer disease. RESULTS: The average level of beta-amyloid 1-42 plasma autoantibodies in patients with MCI that progressed to Alzheimer disease, but not that of the stable cases, was significantly higher than in cognitively normal controls (P < .001). CONCLUSIONS: The results suggest that the plasma beta-amyloid 1-42 autoantibodies parallel beta-amyloid 42 deposition in the brain, which is known to precede by several years the clinical onset of Alzheimer disease. The evaluation of beta-amyloid 1-42 autoantibodies after dissociation of the complexes is a simple and inexpensive method that can be used to predict the occurrence of Alzheimer disease.

The H1 haplotype of the tau gene (MAPT) is associated with mild cognitive impairment.

Mild cognitive impairment is often considered a transitional condition prodromal to Alzheimer's disease. The dissection of genetic risk factors predisposing to mild cognitive impairment is paramount to assess the individual predisposition and reliably evaluate the effectiveness of early therapeutic interventions. We designed a cross-sectional analysis to test whether the occurrence of mild cognitive impairment is influenced by variations of the tau protein gene. The genotypes of seven polymorphisms tagging the major tau haplotypes were assayed on 186 patients with amnestic mild cognitive impairment and 191 unrelated controls. Association study was conducted by logistic regression including APOE genotype and age as covariates. Case-control analysis showed that the common H1 haplotype is significantly overrepresented in patients (OR, 95% CI: 2.31, 1.52-3.51; p<0.001), whereas did not provide positive signals for any of the H1 sub-haplotypes that had been described as associated with Alzheimer inverted exclamation mark s disease. This finding was confirmed when the epsilon4 allele of the APOE gene was taken into account (OR, 95% CI: 2.319, 1.492-3.603; p<0.001). These results firstly suggest that the risk of mild cognitive impairment is influenced by tau protein gene variations and that mild cognitive impairment shares a common genetic background with Alzheimer's disease. They may help elucidating the genetic risk to cognitive decline and designing effective clinical trials.