Statins for the treatment of dementia

Topical issues concerning modern lipid-lowering therapy

Hypercholesterolemia (high levels of atherogenic lipoproteins) is the main modifiable cardiovascular risk factor in most of the populations, including the Russian population. 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) have been used in clinical practice for more than 40 years and have a substantial evidence-based proof of efficacy and safety. Unfortunately, the most of the patients with high cardiovascular risk, including the Russian Federation, still receive initial statin doses and only in 10% of the cases we can reach the recommended target level of low-density lipoprotein cholesterol. This article deals with the current principles of statin therapy according to the latest guidelines and shows updated information concerning the optimization of statin therapy in the elderly and in patients with chronic kidney disease. This article, as well, shows the safety of applying HMG-CoA reductase inhibitors (impact on muscles, liver and cognitive impairments). In addition, the review presents the algorithms for the combination therapy of statins and ezetimibe.

Plasma phosphatidylcholines and vitamin B12/folate levels are possible prognostic biomarkers for progression of Alzheimer's disease

OBJECTIVES

In clinical practice it is important to identify patients suffering from mild cognitive impairment (MCI) who will progress to Alzheimer's disease (AD). The purpose of this study is to investigate whether lipid metabolites and vitamin B12 and folate levels are effective biomarker for an accurate prediction of MCI-to-AD conversion.

METHODS

During the standard diagnostic assessment at our memory clinic 48 cognitively healthy subjects and MCI patients were recruited. These participants were followed up after 7-9 years. Blood was collected, various biochemical markers (including vitamin B12 and folate) analysed and plasma lipids were measured using the AbsoluteIDQ p150 Kit.

RESULTS

There was no significant change in lipid levels in controls converting to MCI. However, we found significant changes in five lipids in converters from controls to AD. Interestingly, also two lipids were altered when MCI re-converted to controls. Vitamin B12 levels were not affected by conversion but folate levels significantly decreased in MCI-AD conversion.

CONCLUSIONS

Taken together, our study provides evidence that some plasma lipids are significantly altered in subjects converting to AD. Future studies will investigate whether the peripheral lipid changes correspond with changes in the brain during the course of the disease. Although this is a small study, there are indications that lipids may be suitable as prognostic markers.

Cognitive Function Assessment in Patients on Moderate- or High-Intensity Statin Therapy

Background

Cardiovascular diseases are the leading cause of death in the USA. Statin therapy reduces cardiovascular events significantly. Cognitive impairment has been reported with statin therapy but there is a lack of consensus. We analyzed the cognitive functions of adult patients who were on moderate-intensity statin therapy (MIST) or high-intensity statin therapy (HIST).

Methods

A total of 213 patients underwent cognitive assessment testing. Cognitive function scores were correlated with the durations of statin therapy, age, and level of education by using Pearson correlation. Independent t-test was used to compare the mean cognitive function score to the gender, race, type of statin therapy, and comorbid conditions.

Results

Mean age of all the patients was 55.4 years. Majority of the patients (66.2%) were on MIST while the rest (33.8%) were on HIST. Cognitive impairment was observed in 17.8% of the studied patients. A total of 41.7% of the patients in the HIST group and 5.7% in the MIST group had cognitive impairment (P < 0.001). There was no correlation between cognitive function score and age (r = -0.106), weakly positive correlation between the level of education and cognitive function score (r = 0.252), and weakly negative correlation between the duration of statin therapy and cognitive function score (r = -0.283). In the group of patients on HIST with cognitive impairment, the proportion of patients on atorvastatin 40 - 80 mg was significantly higher than the proportion of patients on rosuvastatin 20 - 40 mg (66.7% vs. 33.3%; P < 0.05). In the group of patients on MIST with cognitive impairment, atorvastatin 10 - 20 mg was the most commonly used statin therapy (50%), followed by rosuvastatin 10 mg (25%), simvastatin 20 - 40 mg (12.5%) and pravastatin 40 - 80 mg (12.5%).

Conclusions

We found a significantly higher association of cognitive impairment in patients who were on MIST or HIST compared to the general population. We found no correlation between cognitive function score and age, weakly positive correlation between the level of education and cognitive function score, and weakly negative correlation between the duration of statin therapy and cognitive function score. HIST was associated with a higher frequency of cognitive impairment compared to the MIST.

Patient-Reported Outcomes in Online Communications on Statins, Memory, and Cognition: Qualitative Analysis Using Online Communities

BACKGROUND

In drug development clinical trials, there is a need for balance between restricting variables by setting eligibility criteria and representing the broader patient population that may use a product once it is approved. Similarly, although recent policy initiatives focusing on the inclusion of historically underrepresented groups are being implemented, barriers still remain. These limitations of clinical trials may mask potential product benefits and side effects. To bridge these gaps, online communication in health communities may serve as an additional population signal for drug side effects.

OBJECTIVE

The aim of this study was to employ a nontraditional dataset to identify drug side-effect signals. The study was designed to apply both natural language processing (NLP) technology and hands-on linguistic analysis to a set of online posts from known statin users to (1) identify any underlying crossover between the use of statins and impairment of memory or cognition and (2) obtain patient lexicon in their descriptions of experiences with statin medications and memory changes.

METHODS

Researchers utilized user-generated content on Inspire, looking at over 11 million posts across Inspire. Posts were written by patients and caregivers belonging to a variety of communities on Inspire. After identifying these posts, researchers used NLP and hands-on linguistic analysis to draw and expand upon correlations among statin use, memory, and cognition.

RESULTS

NLP analysis of posts identified statistical correlations between statin users and the discussion of memory impairment, which were not observed in control groups. NLP found that, out of all members on Inspire, 3.1% had posted about memory or cognition. In a control group of those who had posted about TNF inhibitors, 6.2% had also posted about memory and cognition. In comparison, of all those who had posted about a statin medication, 22.6% (P<.001) also posted about memory and cognition. Furthermore, linguistic analysis of a sample of posts provided themes and context to these statistical findings. By looking at posts from statin users about memory, four key themes were found and described in detail in the data: memory loss, aphasia, cognitive impairment, and emotional change.

CONCLUSIONS

Correlations from this study point to a need for further research on the impact of statins on memory and cognition. Furthermore, when using nontraditional datasets, such as online communities, NLP and linguistic methodologies broaden the population for identifying side-effect signals. For side effects such as those on memory and cognition, where self-reporting may be unreliable, these methods can provide another avenue to inform patients, providers, and the Food and Drug Administration.

Development of AD-Like Pathology in Skeletal Muscle

Effective therapeutic strategy against Alzheimer's disease (AD) requires early detection of AD; however, clinical diagnosis of Alzheimer's disease (AD) is not precise and a definitive diagnosis of AD is only possible via postmortem examination for AD pathological hallmarks including senile plaques composed of Aβ and neuro fibrillary tangles composed of phosphorylated tau. Although a variety of biomarker has been developed and used in clinical setting, none of them robustly predicts subsequent clinical course of AD. Thus, it is essential to identify new biomarkers that may facilitate the diagnosis of early stages of AD, prediction of subsequent clinical course, and development of new therapeutic strategies. Given that pathological hallmarks of AD including Aβaccumulation and the presence of phosphorylated tau are also detected in peripheral tissues, AD is considered a systemic disease. Without the protection of blood-brain barrier, systemic factors can affect peripheral tissues much earlier than neurons in brain. Here, we will discuss the development of AD-like pathology in skeletal muscle and the potential use of skeletal muscle biopsy (examination for Aβaccumulation and phosphorylated tau) as a biomarker for AD.

Incidence and Comorbidity of Dementia with Lewy Bodies: A Population-Based Cohort Study

Background and Aims

Dementia with Lewy bodies (DLB) is the third most common form of dementia. Epidemiological studies of DLB in Taiwan are scarce. In this study, we estimated the incidence of DLB and comorbidity in the population of Taiwan.

Methods

Data were obtained from the Taiwan National Health Insurance Research Database (NHIRD). DLB patients between 2000 and 2013 were enrolled in assessments of incidence and comorbidity.

Results

The incidence of DLB was shown to be 7.10 per 100,000 person-years (95% CI = 6.63–7.59), which increased with age. The average age at diagnosis was 76.3, and this was higher for males than for females. The comorbidity rates of hypertension and hyperlipidemia in DLB patients were higher in females than in males.

Conclusions

Epidemiologic data from large-scale retrospective studies is crucial to the prevention of DLB.

Systematic review of the efficacy of statins for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most common type of dementia. Recent studies have assessed the possibility of using statins as treatment for AD. However, their efficacy is not clear. In this study, we collected the most relevant information about the efficacy of statins for the treatment of AD. We conducted a systematic literature search using MEDLINE, EMBASE and The Cochrane Library. We included clinical trials, meta-analyses and systematic reviews that analysed the efficacy of statins in AD. We also extracted the characteristics and efficacy results of the studies selected. Of the 304 articles identified, 13 complied with the inclusion criteria. The scientific quality of studies was high and their results indicated that there were no significant differences in the main efficacy variables between statins and placebo treatment for AD. Therefore, according to the available scientific evidence, statins have not shown an improvement in cognition and do not appear to offer significant benefits to patients with AD.

High‑cholesterol diet results in elevated amyloid‑β and oxysterols in rats

The aim of the present study was to investigate the effects of diet cholesterol on oxysterol levels and amyloid‑β (Aβ) production in the peripheral blood and the brains of Sprague‑Dawley (SD) rats. SD rats were randomly divided into five groups and fed 0.015, 0.05, 0.2, 0.5 and 1.6% cholesterol‑containing diets for 8 weeks. The effect of the different diets on the levels of cholesterol, oxysterols [including 27‑hydroxycholesterol (OHC), 24S‑OHC, 7α‑OHC and 7β‑OHC], and the Aβ1‑40 and Aβ1‑42 peptides were examined in the plasma and the brain of the rats. The results demonstrated that diet cholesterol increased the levels of plasma cholesterol in a dose‑dependent manner. The plasma levels of 27‑OHC, 7α‑OHC and 7β‑OHC significantly increased in the 0.5 and 1.6% cholesterol diet groups and the brain levels of 27‑OHC significantly increased in the 1.6% cholesterol diet group. Increased concentration of cholesterol in the diet had no significant influence on plasma and brain levels of 24S‑OHC in the rats. In addition, Aβ1‑40 and Aβ1‑42 levels in plasma and brain were significantly elevated following administration of 0.5 and 1.6% diet cholesterol. The present study revealed that high diet cholesterol contributed to increased level of oxysterols, especially 27‑OHC, in the peripheral blood and the brain, which may be the link between increased peripheral cholesterol and brain Aβ production.

Association of Cognitive Impairment in Patients on 3-Hydroxy-3-Methyl-Glutaryl-CoA Reductase Inhibitors

BACKGROUND

Atherosclerotic cardiovascular diseases are the leading cause of death in the United States. A reduction in cholesterol with 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (statin) significantly reduces mortality and morbidity. Statins may be associated with cognitive impairment or dementia. Our aim was to study the association of cognitive impairment or dementia in patients who were on a statin.

METHODS

Electronic medical records of 3,500 adult patients in our suburban internal medicine office were reviewed.

RESULTS

There were 720 (20.6%) patients in the statin treatment group. Dementia or cognitive impairment was an associated comorbid condition in 7.9% patients in the statin treatment group compared to 3.1% patients in the non-statin group (P < 0.001). Analysis of all of the patients with cognitive impairment or dementia showed that among the age ranges of 51 years through 100 years, the patients in the statin treatment group had a higher prevalence of cognitive impairment or dementia compared to the non-statin group. In the statin treatment group, we found significantly higher prevalence of hyperlipidemia (86.3%), hypertension (69.6%), diabetes mellitus (36.0%), osteoarthritis (31.5%), coronary artery disease (26.1%), hypothyroidism (21.5%) and depression (19.3%) compared to the non-statin group (P < 0.001). About 39.9% of the patients with dementia or cognitive impairment were on statin therapy compared to 18.9% patients who had no dementia or cognitive impairment and were on statin therapy (P < 0.001). Among the patients with cognitive deficit or dementia in the statin treatment group, the majority of the patients were either on atorvastatin (43.9%) or simvastatin (35.1%), followed by rosuvastatin (12.2%) and pravastatin (8.8%). We found greater odds of dementia or cognitive impairment with each year increase in age (1.3 times), in women (2.2 times), African American race (2.7 times), non-consumption of moderate amount of alcohol (two times), diabetes mellitus (1.6 times), hypothyroidism (1.7 times), cerebrovascular accident (3.2 times), and other rheumatological diseases (1.8 times).

CONCLUSIONS

The association of dementia or cognitive impairment was significantly higher in the patients who were on statin therapy compared to the patients who were not on a statin.

Loss of astrocyte cholesterol synthesis disrupts neuronal function and alters whole-body metabolism

Cholesterol is important for normal brain function. The brain synthesizes its own cholesterol, presumably in astrocytes. We have previously shown that diabetes results in decreased brain cholesterol synthesis by a reduction in sterol regulatory element-binding protein 2 (SREBP2)-regulated transcription. Here we show that coculture of control astrocytes with neurons enhances neurite outgrowth, and this is reduced with SREBP2 knockdown astrocytes. In vivo, mice with knockout of SREBP2 in astrocytes have impaired brain development and behavioral and motor defects. These mice also have altered energy balance, altered body composition, and a shift in metabolism toward carbohydrate oxidation driven by increased glucose oxidation by the brain. Thus, SREBP2-mediated cholesterol synthesis in astrocytes plays an important role in brain and neuronal development and function, and altered brain cholesterol synthesis may contribute to the interaction between metabolic diseases, such as diabetes and altered brain function.

Statin Use is Associated with Better Cognitive Function in Elderly with Type 2 Diabetes

The pleiotropic contribution of statins on cognition is uncertain. From 840 patients in the cohort from the Israel Diabetes and Cognitive Decline Study, we identified 61 non-statin users and compared them with 45 patients who had used statins at least 90% of the time. Analysis of covariance was performed to compare mean cognitive z-scores between statin users and non-users while adjusting for socio-demographic, diabetes-related, and cardiovascular covariates which included change in cholesterol by year. Overall cognition, memory, and executive function was found to be significantly better in statin users (p <  0.0008). This suggests a positive effect of statins on cognitive function of type 2 diabetes patients that is independent of cholesterol levels.

Current pharmacotherapy and putative disease-modifying therapy for Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disease of the central nervous system correlated with the progressive loss of cognition and memory. β-Amyloid plaques, neurofibrillary tangles and the deficiency in cholinergic neurotransmission constitute the major hallmarks of the AD. Two major hypotheses have been implicated in the pathogenesis of AD namely the cholinergic hypothesis which ascribed the clinical features of dementia to the deficit cholinergic neurotransmission and the amyloid cascade hypothesis which emphasized on the deposition of insoluble peptides formed due to the faulty cleavage of the amyloid precursor protein. Current pharmacotherapy includes mainly the acetylcholinesterase inhibitors and N-methyl-D-aspartate receptor agonist which offer symptomatic therapy and does not address the underlying cause of the disease. The disease-modifying therapy has garnered a lot of research interest for the development of effective pharmacotherapy for AD. β and γ-Secretase constitute attractive targets that are focussed in the disease-modifying approach. Potentiation of α-secretase also seems to be a promising approach towards the development of an effective anti-Alzheimer therapy. Additionally, the ameliorative agents that prevent aggregation of amyloid peptide and also the ones that modulate inflammation and oxidative damage associated with the disease are focussed upon. Development in the area of the vaccines is in progress to combat the characteristic hallmarks of the disease. Use of cholesterol-lowering agents also is a fruitful strategy for the alleviation of the disease as a close association between the cholesterol and AD has been cited. The present review underlines the major therapeutic strategies for AD with focus on the new developments that are on their way to amend the current therapeutic scenario of the disease.

Etanercept in Alzheimer disease: A randomized, placebo-controlled, double-blind, phase 2 trial

OBJECTIVES

To determine whether the tumor necrosis factor α inhibitor etanercept is well tolerated and obtain preliminary data on its safety in Alzheimer disease dementia.

METHODS

In a double-blind study, patients with mild to moderate Alzheimer disease dementia were randomized (1:1) to subcutaneous etanercept (50 mg) once weekly or identical placebo over a 24-week period. Tolerability and safety of this medication was recorded including secondary outcomes of cognition, global function, behavior, and systemic cytokine levels at baseline, 12 weeks, 24 weeks, and following a 4-week washout period. This trial is registered with EudraCT (2009-013400-31) and ClinicalTrials.gov (NCT01068353).

RESULTS

Forty-one participants (mean age 72.4 years; 61% men) were randomized to etanercept (n = 20) or placebo (n = 21). Etanercept was well tolerated; 90% of participants (18/20) completed the study compared with 71% (15/21) in the placebo group. Although infections were more common in the etanercept group, there were no serious adverse events or new safety concerns. While there were some interesting trends that favored etanercept, there were no statistically significant changes in cognition, behavior, or global function.

CONCLUSIONS

This study showed that subcutaneous etanercept (50 mg/wk) was well tolerated in this small group of patients with Alzheimer disease dementia, but a larger more heterogeneous group needs to be tested before recommending its use for broader groups of patients.

CLASSIFICATION OF EVIDENCE

This study shows Class I evidence that weekly subcutaneous etanercept is well tolerated in Alzheimer disease dementia.

Do statins impair cognition? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

In 2012, the United States Food and Drug Administration (FDA) issued a warning regarding potential adverse effects of HMG-CoA reductase inhibitors (statins) on cognition, based on the Adverse Events Reporting System and a review of the medical literature. We aimed to synthesize randomized clinical trial (RCTs) evidence on the association between statin therapy and cognitive outcomes.

METHODS

We searched MEDLINE, EMBASE, and Cochrane CENTRAL through December 2012, and reviewed published systematic reviews of statin treatment. We sought RCTs that compared statin treatment versus placebo or standard care, and reported at least one cognitive outcome (frequency of adverse cognitive events or measurements using standard neuropsychological cognitive test scores). Studies reporting sufficient information to calculate effect sizes were included in meta-analyses. Standardized and unstandardized mean differences were calculated for continuous outcomes for global cognition and for pre-specified cognitive domains. The main outcome was change in cognition measured by neuropsychological tests; an outcome of secondary interest was the frequency of adverse cognitive events observed during follow-up.

RESULTS

We identified 25 RCTs (all placebo-controlled) reporting cognitive outcomes in 46,836 subjects, of which 23 RCTs reported cognitive test results in 29,012 participants. Adverse cognitive outcomes attributable to statins were rarely reported in trials involving cognitively normal or impaired subjects. Furthermore, meta-analysis of cognitive test data (14 studies; 27,643 participants) failed to show significant adverse effects of statins on all tests of cognition in either cognitively normal subjects (standardized mean difference 0.01, 95% confidence interval, CI, -0.01 to 0.03, p = 0.42) or Alzheimer's disease subjects (standardized mean difference -0.05, 95% CI -0.19 to 0.10, p = 0.38).

CONCLUSIONS

Statin therapy was not associated with cognitive impairment in RCTs. These results raise questions regarding the continued merit of the FDA warning about potential adverse effects of statins on cognition.

Systematic review of atorvastatin for the treatment of Alzheimer's disease

Objective:

To assess the clinical efficacy and safety of atorvastatin in the treatment of Alzheimer's disease.

Data Sources:

Medline (1948/2011-04), Embase (1966/2011-04), Cochrane Library (Issue 3, 2011), Chinese National Knowledge Infrastructure (1989/2011-04), and the Chinese Biomedical Literature Database (1979/2011-04) were searched for randomized clinical trials regardless of language. Abstracts of conference papers were manually searched. Furthermore, Current Controlled Trials (http://controlled-trials.com), Clinical Trials.gov (http://clinicaltrials.gov), and Chinese Clinical Trial Registry (http://www.chictr.org) were also searched. Key words included Alzheimer disease, dementia, cognition, affection, memory dysfunction, hydroxymethylglutaryl-CoA reductase inhibitors, atorvastatin and statins.

Data Selection:

Randomized controlled trials of grade A or B according to quality evaluation criteria of the Cochrane Collaboration were selected, in which atorvastatin and placebo were used to evaluate the effects of atorvastatin in the treatment of Alzheimer's disease. Study methodological quality was evaluated based on criteria described in Cochrane Reviewer's Handbook 5.0.1. Revman 5.1 software was used for data analysis.

Main Outcome Measures:

Clinical efficacy, safety, withdrawal from the studies, and withdrawal due to adverse effects.

Results:

Two randomized controlled trials were included, one was scale A, and the other was scale B. All patients (n = 710, age range 50–90 years) were diagnosed as probable or possible mild to moderate Alzheimer's disease according to standard criteria and treated with atorvastatin 80 mg/d or placebo. There was no difference between the two groups in the final follow-up for Clinical Global Impression of Change scale (WMD = 0.13, 95%CI: –0.15 to 0.40), the Alzheimer's Disease Assessment Scale-cognitive subscale (WMD = 1.05, 95%CI: –3.06 to 6.05), Mini-Mental State Examination Scale (WMD = 0.77, 95%CI: –0.57 to 2.10), and the Neuropsychiatric Instrument (WMD = 2.07, 95%CI: –1.59 to 5.73). The rates of abnormal liver function, withdrawal from treatment, and withdrawal due to adverse effects were higher in the treatment group (OR = 7.86, 95%CI: 2.50-24.69; OR = 4.70, 95%CI: 2.61-8.44; and OR = 5.47, 95%CI: 3.01-9.94; respectively) compared with the placebo group.

Conclusion:

There is insufficient evidence to recommend atorvastatin for the treatment of mild to moderate Alzheimer's disease, because there was no benefit on general function, cognitive function or mental/behavior abnormality outcome measures. Efficacy and safety need to be confirmed by larger and higher quality randomized controlled trials, especially for moderate to severe Alzheimer's disease, because results of this systematic review may be limited by selection bias, implementation bias, as well as measurement bias.

Modulatory role of simvastatin against aluminium chloride-induced behavioural and biochemical changes in rats

Objectives. Aluminium, a neurotoxic agent in humans, has been implicated in the pathogenesis of neurodegenerative disorders. In this study, we examined the behavioral and biochemical effects of aluminium in rats with special emphasis on memory centres, namely, hippocampus and frontal cortex. Further, the effect of simvastatin treatment on aluminium intoxication was evaluated. Methods. Rats were exposed to aluminium chloride (AlCl₃) for 60 days. Simvastatin (10 mg/kg/p.o.) and rivastigmine (1 mg/kg/p.o.) were administered daily prior to AlCl₃. Behavioral parameters were assessed using Morris water maze test and actophotometer followed by biochemical investigations, namely, acetylcholinesterase (AChE) activity, TNF-α level, antioxidant enzymes (GSH, catalase), lipid peroxidation, and nitrite level in hippocampus and frontal cortex. Triglycerides, total cholesterol, LDL, and HDL levels in serum were also determined. Key Findings. Simvastatin treatment improved cognitive function and locomotor activity in rats. Simvastatin reversed hyperlipidemia and significantly rectified the deleterious effect of AlCl₃ on AChE activity. Further, in hippocampus and frontal cortex, aluminium-induced elevation in nitrite and TNF-α and reduction in antioxidant enzymes were inhibited by simvastatin. Conclusion. To conclude, the present study suggests that simvastatin per se protects the neurons in hippocampus and frontal cortex from AlCl₃, an environmental toxin.

Three midlife strategies to prevent cognitive impairment due to Alzheimer's disease

The slow, progressive accumulation of pathology characteristic of Alzheimer's disease is the principal determinant of cognitive decline leading to dementia. Risk-reduction strategies during midlife focus on raising the clinical threshold for the appearance of cognitive symptoms and on reducing the extent of Alzheimer pathology. Best available evidence suggests an approach based on three, conceptually distinct strategies. (1) Raise the threshold for cognitive symptoms by improving brain health. To achieve this goal, the tactic is to reduce cerebrovascular risks mediated by hypertension, diabetes, cigarette smoking, and hyperlipidemia. (2) Raise the threshold for cognitive symptoms by enhancing cognitive reserve. Here, tactics focus on mental stimulation associated with occupation, leisure activities and social engagement. (3) Reduce the burden of Alzheimer pathology. The most promising tactic toward this end is regular aerobic exercise. Tactics in support of strategies to reduce cognitive impairment due to Alzheimer pathology are not yet substantiated by robust, consistent clinical trial evidence. There is pressing need for well-designed pragmatic trials to provide stronger evidence on preventive strategies for late-life cognitive decline and dementia.

Lipid lowering with PCSK9 inhibitors

Statins are the most-effective therapy currently available for lowering the LDL-cholesterol (LDL-C) level and preventing cardiovascular events. Additional therapies are necessary for patients who cannot reach the target LDL-C level when taking the maximum-tolerated dose of a statin. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an enzyme with an important role in lipoprotein metabolism. Rare gain-of-function mutations in PCSK9 lead to a high LDL-C level and premature coronary heart disease, whereas loss-of-function variants lead to a low LDL-C level and a reduced incidence of coronary heart disease. Furthermore, the PCSK9 level is increased with statin therapy through negative feedback, which promotes LDL-receptor degradation and decreases the efficacy of LDL-C lowering with statins. PCSK9 inhibition is, therefore, a rational therapeutic target, and several approaches are being pursued. In phase I, II, and III trials, inhibition of PCSK9 with monoclonal antibodies has produced an additional 50-60% decrease in the LDL-C level when used in combination with statin therapy, compared with statin monotherapy. In short-term trials, PCSK9 inhibitors were well tolerated and had a low incidence of adverse effects. Ongoing phase III trials will provide information about the long-term safety of these drugs, and their efficacy in preventing cardiovascular events.

Unintended effects of statins from observational studies in the general population: systematic review and meta-analysis

BACKGROUND

Efficacy of statins has been extensively studied, with much less information reported on their unintended effects. Evidence from randomized controlled trials (RCTs) on unintended effects is often insufficient to support hypotheses generated from observational studies. We aimed to systematically assess unintended effects of statins from observational studies in general populations with comparison of the findings where possible with those derived from randomized trials.

METHODS

Medline (1998 to January 2012, week 3) and Embase (1998 to 2012, week 6) were searched using the standard BMJ Cohort studies filter. The search was supplemented with reference lists of all identified studies and contact with experts in the field. We included prospective studies with a sample size larger than 1,000 participants, case control (of any size) and routine health service linkage studies of over at least one year duration. Studies in subgroups of patients or follow-up of patient case series were excluded, as well as hospital-based cohort studies.

RESULTS

Ninety studies were identified, reporting on 48 different unintended effects. Statins were associated with lower risks of dementia and cognitive impairment, venous thrombo-embolism, fractures and pneumonia, but these findings were attenuated in analyses restricted to higher quality studies (respectively: OR 0.74 (95% CI 0.62 to 0.87); OR 0.92 (95% CI 0.81 to 1.03); OR 0.97 (95% CI 0.88 to 1.05); OR 0.92 (95% CI 0.83 to 1.02)); and marked heterogeneity of effects across studies remained. Statin use was not related to any increased risk of depression, common eye diseases, renal disorders or arthritis. There was evidence of an increased risk of myopathy, raised liver enzymes and diabetes (respectively: OR 2.63 (95% CI 1.50 to 4.61); OR 1.54 (95% CI 1.47 to 1.62); OR 1.31 (95% CI 0.99 to 1.73)).

CONCLUSIONS

Our systematic review and meta-analyses indicate that high quality observational data can provide relevant evidence on unintended effects of statins to add to the evidence from RCTs. The absolute excess risk of the observed harmful unintended effects of statins is very small compared to the beneficial effects of statins on major cardiovascular events.

Combotherapy and current concepts as well as future strategies for the treatment of Alzheimer's disease

It has been estimated that 35.6 million people globally had dementia in 2010 and the prevalence of dementia has been predicted to double every 20 years. Thus, 115.4 million people may be living with dementia in 2050. Alzheimer's disease (AD) is the leading cause of dementia and is present in 60%-70% of people with dementia. Unfortunately, there are few approved drugs that can alleviate the cognitive or behavioral symptoms of AD dementia. Recent studies have revealed that pathophysiological changes related to AD occur decades before the appearance of clinical symptoms of dementia. This extended preclinical phase of AD provides a critical chance for disease-modifying agents to halt or delay the relentless process of AD. Although several trials targeting various pathological processes are ongoing, the examination of the combined use of different approaches to combat AD seems warranted. In this article, we will review current therapies, future strategies, and ongoing clinical trials for the treatment of AD with a special focus on combination therapies. Furthermore, preventive strategies for cognitively normal subjects in the presymptomatic stages of AD will also be addressed. In this review, we discuss current hypotheses of the disease process. In the decades since the approval of cholinesterase inhibitors, no new drug has ultimately demonstrated clear success in clinical trials. Given the difficulties that have been encountered in attempts to identify a single drug that can treat AD, we must pursue effective multi-target strategies, ie, combination therapies. The combination of cholinesterase inhibitors and memantine is considered well tolerated and safe, and this combination benefits patients with moderate-to-severe AD. In contrast, with the exception of adjuvant therapies of conventional drugs, combinations of different disease-modifying agents with different mechanisms may have promising synergic effects and benefit cognition, behavior, and daily living function.

Effects of HMG-CoA reductase inhibitors on learning and memory in the guinea pig

Statins reduce the risk of death from cardiovascular disease in millions of people worldwide. Recent pharmacovigilance data has suggested that people taking statins have an increased risk of psychiatric adverse events such as amnesia and anxiety. This study aimed to investigate the possibility of statin-induced amnesia through animal models of memory and learning. We conducted extracellular field recordings of synaptic transmission in area CA1 of hippocampal slices to examine the effects of acute cholesterol lowering with lipid lowering drugs. We also assessed the effect of six weeks of simvastatin (2mg/kg/d) and atorvastatin (1mg/kg/d) treatment using the Morris water maze. Long Term Potentiation (LTP) was significantly diminished in the presence of 3µM atorvastatin or simvastatin and by the cholesterol sequestering agent methyl-β-cyclodextrin (MBCD). The effects were reversed in the MBCD but not the statin treated slices by the addition of cholesterol. In the water maze, statin treatment did not cause any deficits in the first five days of reference memory testing, but statin treated guinea pigs preformed significantly worse than control animals in a working memory test. The deficits observed in our experiments in water maze performance and hippocampal LTP are suggestive of statin induced changes in hippocampal plasticity. The effects on LTP are independent of cholesterol regulation, and occur at concentrations that may be relevant to clinical use. Our results may help to explain some of the behavioural changes reported in some people after beginning statin treatment.

Statins more than cholesterol lowering agents in Alzheimer disease: their pleiotropic functions as potential therapeutic targets

Alzheimer disease (AD) is a progressive neurodegenerative disorder characterized by severe cognitive impairment, inability to perform activities of daily living and mood changes. Statins, long known to be beneficial in conditions where dyslipidemia occurs by lowering serum cholesterol levels, also have been proposed for use in neurodegenerative conditions, including AD. However, it is not clear that the purported effectiveness of statins in neurodegenerative disorders is directly related to cholesterol-lowering effects of these agents; rather, the pleiotropic functions of statins likely play critical roles. The aim of this review is to provide an overview on the new discoveries about the effects of statin therapy on the oxidative and nitrosative stress levels as well as on the modulation of the heme oxygenase/biliverdin reductase (HO/BVR) system in the brain. We propose a novel mechanism of action for atorvastatin which, through the activation of HO/BVR-A system, may contribute to the neuroprotective effects thus suggesting a potential therapeutic role in AD and potentially accounting for the observation of decreased AD incidence with persons on statin.

Brain cholesterol metabolism, oxysterols, and dementia

Cholesterol metabolism is implicated in the etiology of Alzheimer's disease (AD) and amyloid production in the brain. While brain cholesterol cannot be measured directly in vivo, the oxysterol, 24S-hydroxycholesterol (24-OHC), is the predominant metabolite of brain cholesterol and can be measured in the blood. The aim of this review is to evaluate plasma 24-OHC as a potential biomarker of AD risk and discuss factors related to its levels in the brain and blood. This systematic review examines studies published between 1950 and June 2012 that examined the relationship between plasma 24-OHC, cognition, brain structure, and dementia using the following key words ("24S-hydroxycholesterol" or "24-hydroxycholesterol") and ("Brain" or "Cognitive"). We found a total of 28 studies of plasma 24-OHC and neurodegenerative disease, including a subset of 12 that used dementia as a clinical endpoint. These studies vary in the direction of the observed associations. Results suggest plasma 24-OHC may be higher in the early stages of cognitive impairment and lower in more advanced stages of AD when compared to cognitively normal controls. Measures of 24-OHC in the blood may be an important potential marker for cholesterol metabolism in the brain and risk of AD. Further studies of plasma 24-OHC and dementia must account for the stage of disease, establish the temporal trends in oxysterol concentrations, and employ neuroimaging modalities to assess the structural and metabolic changes occurring in the brain prior to the onset of cognitive impairment.

Markers of cholesterol transport are associated with amyloid deposition in the brain

Cholesterol is implicated in the development of late-onset Alzheimer's disease (AD). We sought to determine the associations between beta amyloid (Aβ) plaque deposition in vivo using Pittsburgh compound B (PiB) and several indices of cholesterol homeostasis (i.e., total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, apolipoprotein E (ApoE), clusterin, oxysterol metabolites of cholesterol, and previously reported genes associated with late-onset AD) in 175 nondemented elderly subjects. High Aβ deposition was associated significantly with a lower Mini-Mental State Examination score (<27 points, p = 0.04), high systolic blood pressure (p = 0.04), carrying the apolipoprotein E epsilon 4 allele (p < 0.01), and lower plasma ApoE levels (p = 0.02), and variation in the ABCA7 (p = 0.02) and EPHA1 genes (p = 0.02). Cholesterol measures were not related to Aβ deposition in this cohort of nondemented elderly adults. However, plasma and genetic factors relating to cholesterol transport were associated with Aβ deposition in the brain. A better understanding of cholesterol transport mechanisms may lead to the design of potential targets for the prevention of Aβ deposition in the brain.

Biliverdin Reductase-A correlates with inducible nitric oxide synthasein in atorvastatin treated aged canine brain

Alzheimer's disease is a neurodegenerative disorder characterized by progressive cognitive impairment and neuropathology. Recent preclinical and epidemiological studies proposed statins as a possible therapeutic drug for Alzheimer's disease, but the exact mechanisms of action are still unknown. Biliverdin reductase-A is a pleiotropic enzyme involved in cellular stress responses. It not only transforms biliverdin-IX alpha into the antioxidant bilirubin-IX alpha but its serine/threonine/tyrosine kinase activity is able to modulate cell signaling networks. We previously reported the beneficial effects of atorvastatin treatment on biliverdin reductase-A and heme oxygenase-1 in the brains of a well characterized pre-clinical model of Alzheimer's disease, aged beagles, together with observed improvement in cognition. Here we extend our knowledge of the effects of atorvastatin on inducible nitric oxide synthase in parietal cortex, cerebellum and liver of the same animals. We demonstrated that atorvastatin treatment (80 mg/day for 14.5 months) to aged beagles selectively increased inducible nitric oxide synthase in the parietal cortex but not in the cerebellum. In contrast, inducible nitric oxide synthase protein levels were significantly decreased in the liver. Significant positive correlations were found between biliverdin reductase-A and inducible nitric oxide synthase as well as heme oxygenase-1 protein levels in the parietal cortex. The opposite was observed in the liver. Inducible nitric oxide synthase up-regulation in the parietal cortex was positively associated with improved biliverdin reductase-A functions, whereas the oxidative-induced impairment of biliverdin reductase-A in the liver negatively affected inducible nitric oxide synthase expression, thus suggesting a role for biliverdin reductase-A in atorvastatin-dependent inducible nitric oxide synthase changes. Interestingly, increased inducible nitric oxide synthase levels in the parietal cortex were not associated with higher oxidative/nitrosative stress levels. We hypothesize that biliverdin reductase-A-dependent inducible nitric oxide synthase regulation strongly contributes to the cognitive improvement observed following atorvastatin treatment.

PCSK9 Inhibitors: potential in cardiovascular therapeutics

Despite the efficacy of statin therapy, patients treated with these agents face substantial residual risk that is associated with achieved levels of LDL cholesterol (LDL-C). These observations suggest a potential benefit of additional strategies to promote further LDL-C reduction. Proprotein convertase subtilisin/kexin type 9 (PCSK9) has emerged as an attractive target in this regard. Abrogation of PCSK9 function prevents PCSK9-mediated catabolism of LDL receptors, increases cell surface LDL receptor density, and promotes clearance of LDL and other atherogenic lipoproteins from the circulation. Thus far, the most advanced approaches to block PCSK9 action are monoclonal antibodies and anti-sense oligonucleotides. Among statin-treated patients, these agents may produce additional LDL-C lowering exceeding 50 %. In rare genetic experiments of nature, individuals with dominant negative or dual loss of function mutations of PCSK9 appear to have no adverse health effects resulting from lifelong, very low levels of LDL-C. In short-term trials, PCSK9 antibodies have been generally well-tolerated. However, evidence to support long-term safety and efficacy of PCSK9 therapy to reduce cardiovascular risk awaits the results of large cardiovascular outcome trials.

Problems and possible solutions for therapy with statins

Despite issues about the value of statins, benefit for high cardiovascular (CV) risk outweighs problems. However, the practitioner must be aware of concerns, be prepared to respond, and justify statin usage. Symptoms of statin-related myopathy are of more concern than stated by pharmaceutical companies. Occurrence of myopathy symptoms, estimated to be up to 10.4%, can decrease statin adherence of high CV risk patients. Dosage modification, or use of pitavastatin, may help the problematic patient. There are concerns that there may be little benefit of statins for primary prevention in women. However, evidence appears to support statin use in women at high CV risk, both in primary and secondary prevention. Abandoning low-density lipoprotein cholesterol (LDL-C) as a valid target is unwarranted; there is much evidence to support "lower is better." The practitioner must be aware of the complicated processes causing atherosclerosis and when to incorporate new approaches to disease management. Tailoring therapy for CV risk, when indicated, may contribute further to LDL-C reduction. Liver inflammation can occur with statins but is of minimal concern; frequently, statins alleviate the problem. Unless liver transaminases are over three times normal, a statin should be prescribed, if indicated. The net effect of statins on cognition appears to be zero-no harm, no benefit. Despite reports of improved cognition, statins should not be prescribed for this. With diabetes mellitus (DM), statins can increase incidence, but the CV benefit far outweighs any risk. Therefore, statins should be prescribed in DM to reduce CV risk. Statins are a major medical contribution when used appropriately.

A review of the potential therapeutic role of statins in the treatment of Alzheimer's disease: current research and opinion

Alzheimer's disease is one of the most prevalent neurodegenerative disorders. However, there is no current treatment, which definitively influences disease progression over a sustained period. Numerous studies linking an increase in serum cholesterol, mainly during midlife, with the pathogenic process of Alzheimer's disease have been published. Therefore, the role of statins as a therapy in this disorder may be of great interest. The aim of the present review is to summarize of the role of statins in the treatment of Alzheimer's disease.

KIF6 719Arg allele is associated with statin effects on cholesterol levels in amnestic mild cognitive impairment and Alzheimer's disease patients

KIF6 719Arg allele carriers are thought to have a greater lipid lowering response from statin therapy than non-carriers. Given the continued interest in the relationship between cholesterol, statin use, amnestic mild cognitive impairment (aMCI), and Alzheimer's disease (AD), investigating the role of KIF6 719Arg carrier status in these relationships may be of importance. Data from 86 patients (36 aMCI, 50 AD) with an average age of 76.87 ± 8.22 years were used for this study. Total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL), and triglycerides were the outcome variables. 719Arg carriers taking statins had significantly lower TC (p < 0.001) and LDL (p < 0.001) levels than 719Arg carriers not taking statins. In addition, 719Arg carriers not taking statins had significantly higher TC (p = 0.004) and LDL (p < 0.001) than 719Arg non-carriers taking statins. Additional analyses indicated that ApoE ε4 carrier status and statin use interaction is also associated with lower TC (p = 0.04), but not LDL (p = 0.06). The interaction between 719Arg and ApoE ε4 carrier status on TC and LDL was not significant. This study is the first to demonstrate an association between lower cholesterol levels and statin use among KIF6 719Arg allele carriers with aMCI and AD. Accounting for 719Arg carrier status may be important in future studies investigating the link between cholesterol and AD and also for AD and aMCI clinical trials using statins as a treatment.

Current and future treatments for Alzheimer's disease

Alzheimer's dementia (AD) is increasingly being recognized as one of the most important medical and social problems in older people in industrialized and non-industrialized nations. To date, only symptomatic treatments exist for this disease, all trying to counterbalance the neurotransmitter disturbance. Three cholinesterase inhibitors (CIs) are currently available and have been approved for the treatment of mild to moderate AD. A further therapeutic option available for moderate to severe AD is memantine, an N-methyl-D-aspartate receptor noncompetitive antagonist. Treatments capable of stopping or at least effectively modifying the course of AD, referred to as 'disease-modifying' drugs, are still under extensive research. To block the progression of the disease they have to interfere with the pathogenic steps responsible for the clinical symptoms, including the deposition of extracellular amyloid β plaques and intracellular neurofibrillary tangle formation, inflammation, oxidative damage, iron deregulation and cholesterol metabolism. In this review we discuss current symptomatic treatments and new potential disease-modifying therapies for AD that are currently being studied in phase I-III trials.

Restoration of dietary-fat induced blood-brain barrier dysfunction by anti-inflammatory lipid-modulating agents

BACKGROUND

Several studies have identified use of non-steroidal-anti-inflammatory drugs and statins for prevention of dementia, but their efficacy in slowing progression is not well understood. Cerebrovascular disturbances are common pathological feature of Alzheimer's disease. We previously reported chronic ingestion of saturated fatty acids (SFA) compromises blood-brain barrier (BBB) integrity resulting in cerebral extravasation of plasma proteins and inflammation. However, the SFA-induced parenchymal accumulation of plasma proteins could be prevented by co-administration of some cholesterol lowering agents. Restoration of BBB dysfunction is clinically relevant, so the purpose of this study was to explore lipid-lowering agents could reverse BBB disturbances induced by chronic ingestion of SFA's.

METHODS

Wild-type mice were fed an SFA diet for 12 weeks to induce BBB dysfunction, and then randomised to receive atorvastatin, pravastatin or ibuprofen in combination with the SFA-rich diet for 2 or 8 weeks. Abundance of plasma-derived immunoglobulin-G (IgG) and amyloid-β enriched apolipoprotein (apo)-B lipoproteins within brain parenchyme were quantified utilising immunofluorescence microscopy.

RESULTS

Atorvastatin treatment for 2 and 8 weeks restored BBB integrity, indicated by a substantial reduction of IgG and apo B, particularly within the hippocampus. Pravastatin, a water-soluble statin was less effective than atorvastatin (lipid-soluble). Statin effects were independent of changes in plasma lipid homeostasis. Ibuprofen, a lipid-soluble cyclooxygenase inhibitor attenuated cerebral accumulation of IgG and apo B as effectively as atorvastatin. Our findings are consistent with the drug effects being independent of plasma lipid homeostasis.

CONCLUSION

Our findings suggest that BBB dysfunction induced by chronic ingestion of SFA is reversible with timely introduction and sustained treatment with agents that suppress inflammation.

Lipid rafts and Alzheimer's disease: protein-lipid interactions and perturbation of signaling

Lipid rafts are membrane domains, more ordered than the bulk membrane and enriched in cholesterol and sphingolipids. They represent a platform for protein-lipid and protein–protein interactions and for cellular signaling events. In addition to their normal functions, including membrane trafficking, ligand binding (including viruses), axonal development and maintenance of synaptic integrity, rafts have also been implicated in the pathogenesis of several neurodegenerative diseases including Alzheimer’s disease (AD). Lipid rafts promote interaction of the amyloid precursor protein (APP) with the secretase (BACE-1) responsible for generation of the amyloid β peptide, Aβ. Rafts also regulate cholinergic signaling as well as acetylcholinesterase and Aβ interaction. In addition, such major lipid raft components as cholesterol and GM1 ganglioside have been directly implicated in pathogenesis of the disease. Perturbation of lipid raft integrity can also affect various signaling pathways leading to cellular death and AD. In this review, we discuss modulation of APP cleavage by lipid rafts and their components, while also looking at more recent findings on the role of lipid rafts in signaling events.

Cerebrospinal fluid Aβ and tau level fluctuation in an older clinical cohort

OBJECTIVE

To determine whether cerebrospinal fluid (CSF) biomarkers for Alzheimer disease fluctuate significantly over time in a cohort of older, mildly symptomatic individuals.

DESIGN

Biomarker validation in a clinical cohort.

SETTING

University hospital inpatient unit.

PARTICIPANTS

Ten patients admitted for CSF drainage for diagnostic purposes.

MAIN OUTCOME MEASURES

The CSF levels of Aβ1-40, Aβ1-42, tau, and phosphorylated tau on threonine 181 (p-tau(181)) were measured every 6 hours for 24 or 36 hours.

RESULTS

The mean coefficient of variation values for each biomarker assessed in our 10 patients were 5.5% (95% CI, 3.8%-10.0%) for Aβ1-42, 12.2% (9.0%-24.2%) for Aβ1-40, 8.2% (5.7%-15.1%) for total tau, and 11.9% (8.5%-23.0%) for p-tau(181). These values are only slightly higher than the variability in the assay. In addition, no significant circadian fluctuation in any Alzheimer disease biomarker was observed given the limitations of our sampling frequency.

CONCLUSION

In a cohort of elderly patients, little fluctuation in the levels of important Alzheimer disease biomarkers in lumbar CSF is seen as a function of time.

Cholesterol-lowering drugs and incident open-angle glaucoma: a population-based cohort study

Background

Open-angle glaucoma (OAG) is a progressive neurodegenerative disease that may lead to blindness. An elevated intraocular pressure (IOP) is its major risk factor. OAG treatment is currently exclusively directed towards the lowering of the IOP. IOP lowering does not prevent disease progression in all patients and thus other treatment modalities are needed. Earlier studies reported cholesterol-lowering drugs to have neuroprotective properties. The aim of this study was to determine the associations between the use of cholesterol-lowering drugs and incident OAG.

Methodology/Principal Findings

Participants in a prospective population-based cohort study underwent ophthalmic examinations, including IOP measurements and perimetry, at baseline and follow-up. The use of statins and non-statin cholesterol-lowering drugs was monitored continuously during the study. Associations between the use of cholesterol-lowering drugs and incident OAG were analyzed with Cox regression; associations between cholesterol-lowering drugs and IOP at follow-up were analyzed with multiple linear regression. During a mean follow-up of 9.8 years, 108 of 3939 eligible participants (2.7%) developed OAG. The hazard ratio for statin use was 0.54 (95% confidence interval 0.31–0.96; P = 0.034) and for non-statin cholesterol-lowering drugs 2.07 (0.81–5.33; P = 0.13). The effect of statins was more pronounced with prolonged use (hazard ratio 0.89 [0.41–1.94; P = 0.77] for use two years or less; 0.46 [0.23–0.94; P = 0.033] for use more than two years; P-value for trend 0.10). The analyzes were adjusted for age and gender, baseline IOP and IOP-lowering treatment, the family history of glaucoma, and myopia. There was no effect of statins on the IOP.

Conclusions/Significance

Long-term use of statins appears to be associated with a reduced risk of OAG. The observed effect was independent of the IOP. These findings are in line with the idea that statins have neuroprotective properties and may open a way to a new OAG treatment modality.

Therapeutic targets of brain insulin resistance in sporadic Alzheimer's disease

Growing evidence supports roles for brain insulin and insulin-like growth factor (IGF) resistance and metabolic dysfunction in the pathogenesis of Alzheimer's disease (AD). Whether the underlying problem stems from a primary disorder of central nervous system (CNS) neurons and glia, or secondary effects of systemic diseases such as obesity, Type 2 diabetes, or metabolic syndrome, the end-results include impaired glucose utilization, mitochondrial dysfunction, increased oxidative stress, neuroinflammation, and the propagation of cascades that result in the accumulation of neurotoxic misfolded, aggregated, and ubiquitinated fibrillar proteins. This article reviews the roles of impaired insulin and IGF signaling to AD-associated neuronal loss, synaptic disconnection, tau hyperphosphorylation, amyloid-beta accumulation, and impaired energy metabolism, and discusses therapeutic strategies and lifestyle approaches that could be used to prevent, delay the onset, or reduce the severity of AD. Finally, it is critical to recognize that AD is heterogeneous and has a clinical course that fully develops over a period of several decades. Therefore, early and multi-modal preventive and treatment approaches should be regarded as essential.

Treatment of vascular dementia. Recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology

Scientific Department of Cognitive Neurology and Aging of ABN had a consensus meeting to write recommendations on treatment of vascular dementia, there was no previous issue. This disease has numerous particularities and can be considered a preventable dementia. Prevention treatment is primary care of vascular risk factors or a secondary prevention of factors that could cause recurrence of ischemic or hemorrhagic brain modifications. In these guidelines we suggested only symptomatic treatment, pharmacologic or non-pharmacologic. We have reviewed current publications on MEDLINE (PubMed), LILACS e Cochrane Library databases. Recommendations are concern to the following factors and their prevention evidences, association, or treatment of vascular dementia: physical activity, tobacco use, diet and food supplements, arterial hypertension, diabetes mellitus, obesity, statins, cardiac failure, atrial fibrillation, antithrombotics, sleep apnea, carotid revascularization, symptomatic pharmacological treatment.

Cholesterol metabolism in Huntington disease

The CNS is rich in cholesterol, which is essential for neuronal development and survival, synapse maturation, and optimal synaptic activity. Alterations in brain cholesterol homeostasis are linked to neurodegeneration. Studies have demonstrated that Huntington disease (HD), a progressive and fatal neurodegenerative disorder resulting from polyglutamine expansion in the huntingtin protein, is associated with changes in cellular cholesterol metabolism. Emerging evidence from human and animal studies indicates that attenuated brain sterol synthesis and accumulation of cholesterol in neuronal membranes represent two distinct mechanisms occurring in the presence of mutant huntingtin that influence neuronal survival. Increased knowledge of how changes in intraneuronal cholesterol metabolism influence the pathogenesis of HD will provide insights into the potential application of brain cholesterol regulation as a therapeutic strategy for this devastating disease.

Treatment of Alzheimer's disease in Brazil: I. Cognitive disorders

This article reports the recommendations of the Scientific Department of Cognitive Neurology and Aging of the Brazilian Academy of Neurology for the treatment of Alzheimer’s disease (AD) in Brazil, with special focus on cognitive disorders. It constitutes a revision and broadening of the 2005 guidelines based on a consensus involving researchers (physicians and non-physicians) in the field. The authors carried out a search of articles published since 2005 on the MEDLINE, LILACS and Cochrane Library databases. The search criteria were pharmacological and non-pharmacological treatment of cognitive disorders in AD. Studies retrieved were categorized into four classes, and evidence into four levels, based on the 2008 recommendations of the American Academy of Neurology. The recommendations on therapy are pertinent to the dementia phase of AD. Recommendations are proposed for the treatment of cognitive disorders encompassing both pharmacological (including acetyl-cholinesterase inhibitors, memantine and other drugs and substances) and non-pharmacological (including cognitive rehabilitation, physical activity, occupational therapy, and music therapy) approaches. Recommendations for the treatment of behavioral and psychological symptoms of dementia due to Alzheimer’s disease are included in a separate article of this edition.

An improved model for disease progression in patients from the Alzheimer's disease neuroimaging initiative

The objective of this analysis was to develop a semi-mechanistic nonlinear disease progression model using an expanded set of covariates that captures the longitudinal change of Alzheimer's Disease Assessment Scale (ADAS-cog) scores from the Alzheimer's Disease Neuroimaging Initiative study that consisted of 191 Alzheimer disease patients who were followed for 2 years. The model describes the rate of progression and baseline disease severity as a function of influential covariates. The covariates that were tested fell into 4 categories: (1) imaging volumetric measures, (2) serum biomarkers, (3) demographic and genetic factors, and (4) baseline cognitive tests. Covariates found to affect baseline disease status were years since disease onset, hippocampal volume, and ventricular volume. Disease progression rate in the model was influenced by age, total cholesterol, APOE ε4 genotype, Trail Making Test (part B) score, and current levels of impairment as measured by ADAS-cog. Rate of progression was slower for mild and severe Alzheimer patients compared with moderate Alzheimer patients who exhibited faster rates of deterioration. In conclusion, this model describes disease progression in Alzheimer patients using novel covariates that are important for understanding the worsening of ADAS-cog scores over time and may be useful in the future for optimizing study designs through clinical trial simulations.

Cholesterol-independent neuroprotective and neurotoxic activities of statins: perspectives for statin use in Alzheimer disease and other age-related neurodegenerative disorders

Statins, long known to be beneficial in conditions where dyslipidemia occurs by lowering serum cholesterol levels, also have been proposed for use in neurodegenerative conditions, including Alzheimer disease. However, it is not clear that the purported effectiveness of statins in neurodegenerative disorders is directly related to cholesterol-lowering effects of these agents; rather, the pleiotropic functions of statins likely play critical roles. Moreover, it is becoming more apparent with additional studies that statins can have deleterious effects in preclinical studies and lack effectiveness in various recent clinical trials. This perspective paper outlines pros and cons of the use of statins in neurodegenerative disorders, with particular emphasis on Alzheimer disease.

Dental X-ray exposure and Alzheimer's disease: a hypothetical etiological association

Despite the fact that Alzheimer's disease was identified more than 100 years ago, its cause remains elusive. Although the chance of developing Alzheimer's disease increases with age, it is not a natural consequence of aging. This article proposes that dental X-rays can damage microglia telomeres - the structures at the end of chromosomes that determine how many times cells divide before they die - causing them to age prematurely. Degenerated microglia lose their neuroprotective properties, resulting in the formation of neurofibrillary tau tangles and consequently, the neuronal death that causes Alzheimer's dementia. The hypothesis that Alzheimer's is caused specifically by microglia telomere damage would explain the delay of one decade or longer between the presence of Alzheimer's brain pathology and symptoms; telomere damage would not cause any change in microglial function, it would just reset the countdown clock so that senescence and apoptosis occurred earlier than they would have without the environmental insult. Once microglia telomere damage causes premature aging and death, the adjacent neurons are deprived of the physical support, maintenance and nourishment they require to survive. This sequence of events would explain why therapies and vaccines that eliminate amyloid plaques have been unsuccessful in stopping dementia. Regardless of whether clearing plaques is beneficial or harmful - which remains a subject of debate - it does not address the failing microglia population. If microglia telomere damage is causing Alzheimer's disease, self-donated bone marrow or dental pulp stem cell transplants could give rise to new microglia populations that would maintain neuronal health while the original resident microglia population died.

Long-term high-dose atorvastatin decreases brain oxidative and nitrosative stress in a preclinical model of Alzheimer disease: a novel mechanism of action

Alzheimer disease (AD) is an age-related neurodegenerative disorder characterized by progressive memory loss, inability to perform the activities of daily living and personality changes. Unfortunately, drugs effective for this disease are limited to acetylcholinesterase inhibitors that do not impact disease pathogenesis. Statins, which belong to the class of cholesterol-reducing drugs, were proposed as novel agents useful in AD therapy, but the mechanism underlying their neuroprotective effect is still unknown. In this study, we show that atorvastatin may have antioxidant effects, in aged beagles, that represent a natural higher mammalian model of AD. Atorvastatin (80 mg/day for 14.5 months) significantly reduced lipoperoxidation, protein oxidation and nitration, and increased GSH levels in parietal cortex of aged beagles. This effect was specific for brain because it was not paralleled by a concomitant reduction in all these parameters in serum. In addition, atorvastatin slightly reduced the formation of cholesterol oxidation products in cortex but increased the 7-ketocholesterol/total cholesterol ratio in serum. We also found that increased oxidative damage in the parietal cortex was associated with poorer learning (visual discrimination task). Thus, a novel pharmacological effect of atorvastatin mediated by reducing oxidative damage may be one mechanism underlying benefits of this drug in AD.

Neuroprotective therapeutics for Alzheimer's disease: progress and prospects

The number of people with Alzheimer's disease (AD) has never been greater and is set to increase substantially in the decades ahead as the proportion of the population aged 65 years or more rises sharply. There is therefore an urgent need for safe and effective pharmacotherapy to help combat the corresponding and substantial increase in disease burden. Increased understanding of disease aetiology and pathophysiology, particularly in relation to the loss of vulnerable neurons and the formation of plaques and tangles, has increased hope for medications that can slow (or perhaps even halt) the course of the disease. In this article I review the neurobiological basis of AD, current progress towards neuroprotective therapeutics, and prospects for the future.

Mechanisms of amyloid-Beta Peptide uptake by neurons: the role of lipid rafts and lipid raft-associated proteins

A hallmark pathological feature of Alzheimer's disease (AD) is the accumulation of extracellular plaques composed of the amyloid-beta (Aβ) peptide. Thus, classically experiments were designed to examine Aβ toxicities within the central nervous system (CNS) from the extracellular space. However, a significant amount of evidence now suggests that intraneuronal accumulation of Aβ is neurotoxic and may play an important role in the disease progression of AD. One of the means by which neurons accumulate intracellular Aβ is through uptake of extracellular Aβ peptides, and this process may be a potential link between Aβ generation, synaptic dysfunction, and AD pathology. Recent studies have found that neuronal internalization of Aβ involves lipid rafts and various lipid raft-associated receptor proteins. Uptake mechanisms independent of lipid rafts have also been implicated. The aim of this paper is to summarize these findings and discuss their significance in the pathogenesis of AD.