Background. Dementia is a multi-etiologic syndrome characterized by multiple cognitive deficits but not always by the presence of cognitive impairment. Cognitive impairment is associated with multiple non-modifiable risk factors but few modifiable factors. Epidemiological studies have shown an association between periodontitis, a potentially modifiable risk factor, and cognitive impairment.Objectives. To determine whether clinical periodontitis is associated with the diagnosis of cognitive impairment/dementia after controlling for known risk factors, including age, sex, and educational level.Methods. A case-control study was conducted in Granada, Spain, in two groups of dentate individuals over 50 years of age: cases with a firm diagnosis of mild cognitive impairment or dementia of any type or severity, and controls with no subjective memory loss complaints and a score >30 in the "Phototest" cognitive test (screening test for cognitive impairment). Periodontitis was evaluated by measuring tooth loss, plaque and bleeding indexes, pocket depths, and clinical attachment loss.Results. The study included 409 dentate adults, 180 with cognitive impairment and 229 without. A moderate and statistically significant association was observed between clinical attachment loss and cognitive impairment after controlling for age, sex, educational level, oral hygiene habits, and hyperlipidemia (p=0.049). No significant association was found between tooth loss and cognitive impairment.Conclusion. Periodontitis appears to be associated with cognitive impairment after controlling for confounders such as age, sex, and educational level. KEY WORDS.Periodontitis, periodontal attachment loss, mild cognitive impairment, dementia.Dementia is a multi-etiologic syndrome characterized by the acquired involvement of multiple cognitive/behavioral domains that compromise the sufferer's functional capacity 1 . It largely affects the elderly, although it can commence at any age 1 . Mild cognitive impairment is an intermediate state, frequently appearing before the development of dementia, in which the cognitive and behavioral impairment is not sufficiently severe to have functional repercussions 2 . The main cause of dementia is Alzheimer's Disease (AD), a neurodegenerative process of multifactorial and complex etiology associated with multiple risk and protective factors; its prevalence increases exponentially with age from 65 years on, and it represents one of the main socio-health problems faced by the developed world 3 . It is estimated that there will be 35.6 million individuals with dementia worldwide in 2010 and that this number will double every 20 years, reaching more than 115 million by 2050 1 . The magnitude of the challenge and the 1 Journal of Periodontology; absence of curative treatments make the development of preventive measures a matter of extreme urgency. Although many risk factors are non-modifiable (e.g., age, sex, and genetic risk factors), others are susceptible to modification through individual choices, e.g., certain dieta...

There is growing evidence to support the hypothesis that statins may act as neuroprotectants in several neuropathological conditions, including Alzheimer's disease. The mechanisms for neuroprotection are only partially understood, however, and pleiotropic phenomena could be involved. We have made a comparative study of 9 statins (lovastatin, mevastatin, pravastatin, simvastatin, cerivastatin, atorvastatin, fluvastatin, pitavastatin, and rosuvastatin), analyzing several parameters that could be related to neuroprotection, such as chemical structure, lipophilicity, potential blood-brain-barrier penetration (BBB), 3-hydroxy-3-methylglutaryl co-enzyme A reductase inhibition, cholesterol modulation in neurons, glia, and human hepatocyte cell lines, and protection against neurodegeneration caused by tau hyperphosphorylation induced by okadaic acid. Our results indicate that monacolin J derivatives (natural and semi-synthetic statins) are the best candidates for the prevention of neurodegenerative conditions due to their higher potential BBB penetration capacity, cholesterol lowering effect on neurons with a satisfactory safety profile, and in vitro protection against cell death caused by okadaic acid in culture. Among the nine statins studied, simvastatin presented the best characteristics for preventing neurodegenerative conditions.

MS-based quantitative proteomics plays an increasingly important role in biological and medical research and the development of these techniques remains one of the most important challenges in mass spectrometry. Numerous stable isotope labeling approaches have been proposed. However, and particularly in the case of 18 O-labeling, a standard protocol of general applicability is still lacking, and statistical issues associated to these methods remain to be investigated. In this work we present an improved high-throughput quantitative proteomics method based on whole proteome concentration by SDS-PAGE, optimized in-gel digestion, peptide 18 O-labeling, and separation by off-gel isoelectric focusing followed by liquid chromatography-LIT-MS. We demonstrate that the off-gel technique is fully compatible with 18 The analysis of differential protein expression is fundamental for the understanding of biological processes and plays an increasingly important role in biological and medical research (1). In recent years, numerous stable isotope labeling (SIL) 1 techniques have emerged as alternatives to the historically used two-dimensional-based approaches for semiquantitative proteomic studies. In these techniques the quantification is done in the same mass spectrometer where peptides are analyzed by tandem mass spectrometry (MS/MS), so relative quantification and peptide identification is performed at the same time. The differences among the several existing SIL approaches are mainly related to the way labels are introduced and the method used to perform the quantification by MS. Thus, in the SILAC method (2) labels are introduced metabolically at the protein level before peptides are generated from protein by enzymatic digestion, minimizing variability introduced by peptide preparation, whereas in the others labeling is performed postdigestion at the peptide level, either chemically in the iTRAQ method (3), or enzymatically in the 18 O labeling method (4 -6). In the iTRAQ method, quantification is made at the MS/MS level, allowing the possibility of performing multiplexed comparisons (7) whereas in SILAC and 18 O methods peptides are quantified at the MS level and are mainly used for pairwise comparisons. In other SIL approaches, such as the ICAT method (8), labeled peptides are specifically recovered after an affinity purification approach; this allows reducing peptide complexity, which is particularly appropriate to selectively analyze peptide subpopulations, such as reduced or oxidized cys-containing peptides (9). The 18 O labeling method has the advantage that labels are intro-

Herpes simplex virus type 1 (HSV-1) is neurotropic and enters a latent state lasting the lifetime of the host. This pathogen has recently been proposed as a risk factor for Alzheimer's disease (AD) in conjunction with apolipoprotein E4 (ApoE4). In a murine acute infection model, we showed that viral neuroinvasiveness depends directly on the overall ApoE dosage and especially on the presence of isoform ApoE4. If an interaction between ApoE and HSV-1 is involved in AD, it may occur during latency rather than during acute infection. Certainly, ApoE plays an important role in late-onset AD, i.e., at a time in life when the majority of people harbor HSV-1 in their nervous system. In the present work, wild-type, APOE knockout, APOE3, and APOE4 transgenic mice were used to analyze the influence of the ApoE profile on the levels of latent virus DNA. The knockout mice had significantly lower concentrations of the virus in the nervous system than the wild-type mice, while the APOE4 mice had very high levels in the brain compared to the APOE3 animals. ApoE4 seems to facilitate HSV-1 latency in the brain much more so than ApoE3. The APOE dosage correlated directly with the HSV-1 DNA concentration in the brain, strengthening the hypothesis that HSV-1, together with ApoE, might be involved in AD.

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Statins have recently been shown to act as protectants against several neuropathological conditions. They have received special attention in the field of Alzheimer's disease (AD), where epidemiological studies indicating a lower prevalence of AD/dementia in statin-prescribed populations. Excitotoxicity, which derives from the overstimulation of glutamate receptors, is a major cause of neuron death in several neurological diseases, including AD and epilepsy. We have carried out a comparative study to investigate the effects of all the commercially available statins (simvastatin, lovastatin, fluvastatin, pravastatin, and atorvastatin) on neuron damage and memory impairment. To this end, we studied neurodegeneration in a mouse model by systemic administration of kainate. Simvastatin was the most effective statin in reducing the deleterious effects caused by kainate, including the severity of seizures, excitotoxicity, oxidative damage, neuritic dystrophy and apoptosis in the hippocampus and other limbic structures of the brain cortex. Lovastatin was the second most efficient statin in preventing seizures and histopathological signs of excitotoxicity, whilst fluvastatin, pravastatin, and atorvastatin showed neither antiepileptic nor neuroprotective effects. Only simvastatin enhanced episodic-like memory. To the best of our knowledge this is the first in vivo study to analyze the neuroprotective effect of all the commercially available statins. Our results suggest that both simvastatin and lovastatin (but especially simvastatin) may well have therapeutic potential in the treatment of neurodegenerative diseases involving excitotoxicity and memory impairment, including AD.

In vivo bioluminescence imaging is becoming increasingly popular. Quantification of bioluminescent signals requires knowledge of the variability and reproducibility of this technique. The objective of this study was to analyze the time course of luminescent signal emitted from firefly luciferase-expressing tumors in two locations, following luciferin injection and at different times after tumor cell implantation. Knowledge of the kinetics of the bioluminescent signals is required for the reliable quantification and comparison of signal during longitudinal studies. The kinetics of bioluminescence was evaluated in orthotopic and heterotopic brain tumors in mice using a human brain tumor cell line constitutively expressing luciferase. Tumor cells were implanted in the brains and flanks of the animals, and wholebody images revealing tumor location were obtained. Tumor burden was monitored over time by the quantitation of photon emission. The magnitude of bioluminescence measured in vivo varied with time after the injection of luciferin, as well as with dose, which necessitated that the comparison of the quantitative results take into consideration the time after injection. Heterotopic and orthotopic tumors exhibited significantly different time courses; however, time after implantation as characterized by kinetic studies performed on days 4 and 14 after cell implantation revealed no significant differences in orthotopic tumors. Future quantitative longitudinal studies must take into account the differences in the kinetics of different models.

Apolipoprotein E (ApoE), a constituent of the lipoproteins, may be relevant in herpes simplex virus type 1 (HSV-1) infection of the central nervous system (CNS), since HSV-1 binds to human serum ApoE lipoproteins. This study demonstrates the involvement of ApoE in the hematogenous route of HSV-1 to the CNS