Molecular mechanisms underlying the effects of statins in the central nervous system

Combined pitavastatin and dacarbazine treatment activates apoptosis and autophagy resulting in synergistic cytotoxicity in melanoma cells

Melanoma is an aggressive skin cancer and its incidence is increasing faster than any other type of cancer. Whilst dacarbazine (DTIC) is the standard chemotherapy for metastatic melanoma, it has limited success. Statins, including pitavastatin, have been demonstrated to have a range of anti-cancer effects in a number of human cancer cell lines. The present study therefore explored the anti-cancer activity of combined DTIC and pitavastatin in A375 and WM115 human melanoma cells. Cell survival assays demonstrated that combined DTIC and pitavastatin treatment resulted in synergistic cell death. Cell cycle analyses further revealed that this combined treatment resulted in a G1 cell cycle arrest, as well as a sub-G1 population, indicative of apoptosis. Activation of apoptosis was confirmed by Annexin V-fluorescein isothiocyanate/propidium iodide double-staining and an increase in the levels of active caspase 3 and cleaved poly (ADP-ribose) polymerase. Furthermore, it was demonstrated that apoptosis occurs through the intrinsic pathway, evident from the release of cytochrome c. Finally, combined DTIC and pitavastatin treatment was demonstrated to also activate autophagy as part of a cell death mechanism. The present study provides novel evidence to suggest that the combined treatment of DTIC and pitavastatin may be effective in the treatment of melanoma.

Psychological issues and cognitive impairment in adults with familial hypercholesterolemia

A literature review about depression, anxiety, illness perception and neurocognitive impairment in adults with familial hypercholesterolemia (FH) was performed. Through PubMed and PsycINFO published studies from 1980 until March 2017 were searched. Two papers assessed depression and anxiety. Four papers explored illness perception. Five studies assessed cognitive impairment. Mean depression and anxiety scores were within normal range. From the reviewed research, it can be concluded that deficits in executive functioning and memory appear in FH patients between 18 and 40 years old, and mild cognitive impairment in older than 50. The research in the field of the present review is relatively recent: all the studies have been published in the current century. Further research should be done using complete standardized neuropsychological assessment and brain imaging techniques. Studies exploring the possible influence of cognitive deficits on adherence should be conducted also.

Statin use and cognitive function in middle-aged adults with type 1 diabetes

AIM

To test associations between statin use and cognitive impairment in adults with childhood-onset type 1 diabetes (T1D).

METHODS

In 2010-13, n = 108 middle-aged participants from ongoing observational Pittsburgh Epidemiology of Diabetes Complications Study underwent neurocognitive assessment (mean age and T1D duration of 49 and 41 years, respectively). All were diagnosed with childhood-onset (i.e., prior to age 18) T1D between 1950 and 1980 and were seen within one year of diagnosis at Children’s Hospital of Pittsburgh. Self-reported statin use (yes/no and if yes, name of statin) was collected biennially from parent study baseline (1986-1988) to time of neurocognitive testing. Logistic regression models tested associations between statin use groups and cognitive impairment (defined as having two or more cognitive test scores 1.5SD or worse than published norms) while linear regression models tested associations between statin use groups and cognitive domain z-scores (domains: Verbal IQ, memory, executive function, psychomotor speed, and visuo-construction). All models controlled for education and age. To address confounding by indication, models were repeated using a propensity score for statin use.

RESULTS

Of the 108 participants, 51 reported never using statins. Median duration of statin use among the 57 ever users was 6 years. These 57 ever statin users were split to create two groups (≤ or > median years of statin use): 1-6 years (n = 25), and 7-12 years (n = 32). Compared with never users, using statins 1-6 years tripled the odds of cognitive impairment (OR = 3.16; 95%CI: 0.93-10.72; P = 0.06) and using statins 7-12 years almost quintupled the odds of cognitive impairment (OR = 4.84; 95%CI: 1.63-14.44; P = 0.005). Compared with never users, using statins 1-6 or 7-12 years was related to worse performance in the memory domain (β = -0.52; P = 0.003, and -0.39; P = 0.014, respectively). Adjusting for coronary artery disease, low density lipoprotein cholesterol, and Apo E4 status did not substantially alter results, and none of these covariates were significantly related to cognitive outcomes (all P > 0.05). Propensity score analyses support that associations between poor cognitive outcomes and statin use were not due merely to confounding by indication.

CONCLUSION

Statin use was associated with cognitive impairment, particularly affecting memory, in these middle-aged adults with childhood-onset T1D, whom at this age, should not yet manifest age-related memory deficits.

Statin-Associated Side Effects

Hydroxy-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors or statins are well tolerated, but associated with various statin-associated symptoms (SAS), including statin-associated muscle symptoms (SAMS), diabetes mellitus (DM), and central nervous system complaints. These are "statin-associated symptoms" because they are rare in clinical trials, making their causative relationship to statins unclear. SAS are, nevertheless, important because they prompt dose reduction or discontinuation of these life-saving mediations. SAMS is the most frequent SAS, and mild myalgia may affect 5% to 10% of statin users. Clinically important muscle symptoms, including rhabdomyolysis and statin-induced necrotizing autoimmune myopathy (SINAM), are rare. Antibodies against HMG-CoA reductase apparently provoke SINAM. Good evidence links statins to DM, but evidence linking statins to other SAS is largely anecdotal. Management of SAS requires making the possible diagnosis, altering or discontinuing the statin treatment, and using alternative lipid-lowering therapy.

Implications of cerebrovascular ATP-binding cassette transporter G1 (ABCG1) and apolipoprotein M in cholesterol transport at the blood-brain barrier

Impaired cholesterol/lipoprotein metabolism is linked to neurodegenerative diseases such as Alzheimer's disease (AD). Cerebral cholesterol homeostasis is maintained by the highly efficient blood-brain barrier (BBB) and flux of the oxysterols 24(S)-hydroxycholesterol and 27-hydroxycholesterol, potent liver-X-receptor (LXR) activators. HDL and their apolipoproteins are crucial for cerebral lipid transfer, and loss of ATP binding cassette transporters (ABC)G1 and G4 results in toxic accumulation of oxysterols in the brain. The HDL-associated apolipoprotein (apo)M is positively correlated with pre-β HDL formation in plasma; its presence and function in the brain was thus far unknown. Using an in vitro model of the BBB, we examined expression, regulation, and functions of ABCG1, ABCG4, and apoM in primary porcine brain capillary endothelial cells (pBCEC). RT Q-PCR analyses and immunoblotting revealed that in addition to ABCA1 and scavenger receptor, class B, type I (SR-BI), pBCEC express high levels of ABCG1, which was up-regulated by LXR activation. Immunofluorescent staining, site-specific biotinylation and immunoprecipitation revealed that ABCG1 is localized both to early and late endosomes and on apical and basolateral plasma membranes. Using siRNA interference to silence ABCG1 (by 50%) reduced HDL-mediated [³H]-cholesterol efflux (by 50%) but did not reduce [³H]-24(S)-hydroxycholesterol efflux. In addition to apoA-I, pBCEC express and secrete apoM mainly to the basolateral (brain) compartment. HDL enhanced expression and secretion of apoM by pBCEC, apoM-enriched HDL promoted cellular cholesterol efflux more efficiently than apoM-free HDL, while apoM-silencing diminished cellular cholesterol release. We suggest that ABCG1 and apoM are centrally involved in regulation of cholesterol metabolism/turnover at the BBB.

Statins Reduce Lipopolysaccharide-Induced Cytokine and Inflammatory Mediator Release in an In Vitro Model of Microglial-Like Cells

The anti-inflammatory effects of statins (HMG-CoA reductase inhibitors) within the cardiovascular system are well-established; however, their neuroinflammatory potential is unclear. It is currently unknown whether statins' neurological effects are lipid-dependent or due to pleiotropic mechanisms. Therefore, the assumption that all statin compounds will have the same effect within the central nervous system is potentially inappropriate, with no studies to date having compared all statins in a single model. Thus, the aim of this study was to compare the effects of the six statins (atorvastatin, fluvastatin, pitavastatin, pravastatin, rosuvastatin, and simvastatin) within a single in vitro model of neuroinflammation. To achieve this, PMA-differentiated THP-1 cells were used as surrogate microglial cells, and LPS was used to induce inflammatory conditions. Here, we show that pretreatment with all statins was able to significantly reduce LPS-induced interleukin (IL)-1β and tumour necrosis factor (TNF)-α release, as well as decrease LPS-induced prostaglandin E2 (PGE2). Similarly, global reactive oxygen species (ROS) and nitric oxide (NO) production were decreased following pretreatment with all statins. Based on these findings, it is suggested that more complex cellular models should be considered to further compare individual statin compounds, including translation into in vivo models of acute and/or chronic neuroinflammation.

Simultaneous administration of fluoxetine and simvastatin ameliorates lipid profile, improves brain level of neurotransmitters, and increases bioavailability of simvastatin

Simvastatin (STT), a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, is widely prescribed for dyslipidemia, whereas fluoxetine (FLX) is the first-choice drug for the treatment of depression and anxiety. A recent report suggests that selective serotonin reuptake inhibitors can interact with the cytochrome P450 3A4 substrate, and another one suggests that STT enhances the antidepressant activity of FLX. However, the data are inconclusive. The present study was designed to explore the pharmacokinetic and pharmacodynamic consequences of coadministration of STT and FLX in experimental animals. For this, Wistar rats weighing 250±10 g were divided into four groups, including control, STT (40 mg/kg/day), FLX (20 mg/kg/day), and STT+FLX group, respectively. After the dosing period of 4 weeks, the animals were sacrificed, and the blood and brain samples were collected for the analysis of STT, simvastatin acid (STA), FLX, total cholesterol, triglyceride, high-density lipoprotein (HDL), 5-hydroxytryptamine, dopamine, and hydroxy indole acetic acid. It was found that the coadministration resulted in a significant increase in the bioavailability of STT in the plasma (41.8%) and brain (68.7%) compared to administration of STT alone (p<0.05). The maximum drug concentration (C_max) of STT was also found to be increased significantly in the plasma and brain compared to that achieved after monotherapy (p<0.05). However, STT failed to improve the pharmacokinetics of FLX up to a significant level. The results of this study showed that the combined regimen significantly reduced the level of cholesterol and triglyceride and increased the level of HDL when compared to STT monotherapy. Furthermore, the coadministration of STT with FLX led to an elevated level of neurotransmitters in the brain (p<0.05). FLX increased the concentration of STT in the plasma and brain. The coadministration of these drugs also led to an improved lipid profile. However, in the long-term, this interaction may have a vital clinical importance because the increase in STT level may lead to life-threatening side effects associated with statins.

Hyperlipidemia and statins use for the risk of new-onset anxiety/depression in patients with head and neck cancer: A population-based study

Objective

Anxiety/depression is common among patients with head and neck cancer (HNC), and can negatively affect treatment compliance and outcome. The aim of this study was to assess the association between hyperlipidemia and the risk of new-onset anxiety/depression after the diagnosis of HNC and the influence of administering statins.

Methods

A matched longitudinal cohort study of 1632 subjects (408 HNC patients with preexisting hyperlipidemia and 1224 age- and sex-matched HNC patients without hyperlipidemia) was included and analyzed by using data from Taiwan’s National Health Insurance Research Database from January 1996 to December 2012. The incidence and hazard ratios (HRs) for the development of new-onset anxiety/depression were examined between the two groups. Cox proportional hazard regression was applied to estimate the relative risks of anxiety/depressive disorders adjusted for potential confounding factors. To estimate the risks of anxiety/depression in different sub-groups, a stratified analysis was also used.

Results

HNC patients with preexisting hyperlipidemia had a higher risk for comorbidities such as hypertension, diabetes mellitus, and cardiovascular disease (P <0.001). The incidence rate of anxiety/depression in the HNC patients with preexisting hyperlipidemia was also significantly higher than that among patients without hyperlipidemia (10.78% vs 7.27%, respectively; P = 0.03). A Cox regression model revealed that preexisting hyperlipidemia was an independent risk factor for anxiety/depression (aHR, 1.96; 95% CI, 1.30–2.94). Statins use was protective against anxiety/depression among HNC patients with hyperlipidemia (aHR, 0.85; 95% CI, 0.46–1.57), especially for individuals older than 65 years and for females.

Conclusions

Preexisting hyperlipidemia was associated with increased risk of new-onset anxiety/depression in the HNC patients. Statins use for HNC patients with hyperlipidemia could decrease the risk of anxiety/depression, especially for those older than 65 years and for female patients.

Pharmacodynamic and pharmacokinetic interactions between simvastatin and diazepam in rats

BACKGROUND

Statins and benzodiazepines are widely used drugs, especially in ischemic heart disease, where exacerbation caused by anxiety can even lead to cardiac death. There have not been any reports of statin drug interaction with anxiolytics so far, but it is possible that these drugs interact with each other. We examined the effect of chronic oral administration of simvastatin on the anxiolytic activity and pharmacokinetics of diazepam in rats.

METHODS

Studies were conducted on male Wistar Han rats treated with simvastatin (2.5, 5, 10, 20mg/kg) for 4-6 weeks, and/or diazepam (2.5, 5, 10mg/kg) administered once on the day of the study. Evaluation of potential pharmacodynamic interaction was based on the behavioral tests: elevated plus maze (EPM) test and the Vogel conflict test (VCT). The assessment of the potential pharmacokinetic interaction was based on measurements of concentrations of diazepam and its metabolites in the blood of animals.

RESULTS

Diazepam 5 and 10mg/kg given together with simvastatin 10 and 20mg/kg showed no anxiolytic effect in the EPM test. In the VCT diazepam combinations with simvastatin did not produce any anxiolytic effect either, with an exception of the co-administration of diazepam 10mg/kg and simvastatin 10mg/kg. Simvastatin (20mg/kg) significantly reduced the area under curve (AUC) of diazepam by 51.6% and temazepam by 54.6%.

CONCLUSIONS

Abolition of diazepam anxiolytic effect during concomitant use of simvastatin is probably caused by diminished bioavailability of diazepam, although pharmacodynamic interaction between these drugs cannot be excluded.

Screening for Small Molecule Inhibitors of Statin-Induced APP C-terminal Toxic Fragment Production

Alzheimer's disease (AD) is characterized by neuronal and synaptic loss. One process that could contribute to this loss is the intracellular caspase cleavage of the amyloid precursor protein (APP) resulting in release of the toxic C-terminal 31-amino acid peptide APP-C31 along with the production of APPΔC31, full-length APP minus the C-terminal 31 amino acids. We previously found that a mutation in APP that prevents this caspase cleavage ameliorated synaptic loss and cognitive impairment in a murine AD model. Thus, inhibition of this cleavage is a reasonable target for new therapeutic development. In order to identify small molecules that inhibit the generation of APP-C31, we first used an APPΔC31 cleavage site-specific antibody to develop an AlphaLISA to screen several chemical compound libraries for the level of N-terminal fragment production. This antibody was also used to develop an ELISA for validation studies. In both high throughput screening (HTS) and validation testing, the ability of compounds to inhibit simvastatin- (HTS) or cerivastatin- (validation studies) induced caspase cleavage at the APP-D720 cleavage site was determined in Chinese hamster ovary (CHO) cells stably transfected with wildtype (wt) human APP (CHO-7W). Several compounds, as well as control pan-caspase inhibitor Q-VD-OPh, inhibited APPΔC31 production (measured fragment) and rescued cell death in a dose-dependent manner. The effective compounds fell into several classes including SERCA inhibitors, inhibitors of Wnt signaling, and calcium channel antagonists. Further studies are underway to evaluate the efficacy of lead compounds - identified here using cells and tissues expressing wt human APP - in mouse models of AD expressing mutated human APP, as well as to identify additional compounds and determine the mechanisms by which they exert their effects.

Chemopreventive effect of omega-3 polyunsaturated fatty acids and atorvastatin in rats with bladder cancer

Bladder cancer remains a huge concern for the medical community because of its incidence and prevalence rates, as well as high percentage of recurrence and progression. Omega-3 polyunsaturated fatty acids and atorvastatin proved anti-inflammatory effects through peroxisome proliferator-activated receptor gamma mechanism. However, their chemopreventive effect still remained to be examined and clarified. In this study, bladder cancer was induced in rats by the chemical carcinogen N-butyl-N-(4-hydroxybutyl)nitrosamine. Omega-3 polyunsaturated fatty acids (docosahexaenoic acid and eicosapentaenoic acid: 2:3 w/w; 1200 mg/kg) and/or atorvastatin (6 mg/kg) were given orally daily to rats for eight consecutive weeks concomitantly with N-butyl-N-(4-hydroxybutyl)nitrosamine and continued for further 4 weeks after cessation of N-butyl-N-(4-hydroxybutyl)nitrosamine administration. The histopathological examination of rat bladder revealed the presence of tumors and the absence of apoptotic bodies in sections from N-butyl-N-(4-hydroxybutyl)nitrosamine group, while tumors were absent and apoptotic bodies were clearly observed in sections from rat groups treated with omega-3 polyunsaturated fatty acids, atorvastatin, or both drugs. The study of the molecular mechanisms illustrated downregulation of COX-2 and P53 (mutant) genes and suppression of transforming growth factor beta-1 and the lipid peroxidation product malondialdehyde in serum of rats of the three treated groups. This chemopreventive effect was confirmed by and associated with lower level of bladder tumor antigen in urine. However, the combined treatment with both drugs exhibited the major protective effect and nearly corrected the dyslipidemia that has been induced by N-butyl-N-(4-hydroxybutyl)nitrosamine. Collectively, omega-3 polyunsaturated fatty acids and atorvastatin, besides having anti-inflammatory properties, proved a chemopreventive effect against bladder cancer, which nominates them to be used as adjuvant therapy with other chemotherapeutics.

SIMVASTATIN DECREASES SEX HORMONE LEVELS IN MALE RATS

OBJECTIVE

Statins can inhibit therate-limiting enzyme hydroxymethyl glutaric acid-coenzyme A reductase to reduce cholesterol biosynthesis, and they are used frequently in the clinic. Cholesterol is also a precursor for sex hormones. However, it is not clear whether statins can affect sex hormone levels. The aim of this study was to investigate the effect of long-term use of statins on sex hormone levels in vivo.

METHODS

Forty male Sprague-Dawley rats were randomly divided into four groups. Three simvastatin groups were administered different doses of simvastatin intragastrically daily (4, 8, or 16 mg/kg/day, n = 10). The control group was administered vehicle intragastrically daily (n = 10). The serum lipid spectrum and testosterone, estradiol, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels were measured before (0 weeks) and after 20 and 40 weeks of simvastatin administration.

RESULTS

In the control group, there were no statistically significant differences between lipid levels, liver function, or sex hormone levels before and after intragastric administration. Compared with the previous intragastric administration group, there was no obvious change in liver function with different doses of simvastatin. However, serum levels of total cholesterol, low-density-lipoprotein cholesterol, triglycerides, testosterone, estradiol, and progesterone were markedly decreased in a dose- and time-dependent manner. By contrast, the levels of FSH and LH were significantly higher, showing feedback regulation.

CONCLUSION

Long-term simvastatin intake reduces serum testosterone, estradiol, and progesterone levels in male rats.

ABBREVIATIONS

HMG-CoA = hydroxymethyl glutaric acid CoA LDL = low-density lipoprotein LDL-C = low-density-lipoprotein cholesterol FSH = follicle-stimulating hormone LH = luteinizing hormone.

Statin non-adherence and residual cardiovascular risk: There is need for substantial improvement

Although statin therapy has proven to be the cornerstone for prevention and treatment of cardiovascular disease (CVD), there are many patients for whom long-term therapy remains suboptimal. The aims of this article are to review the current complex issues associated with statin use and to explore when novel treatment approaches should be considered. Statin discontinuation as well as adherence to statin therapy remain two of the greatest challenges for lipidologists. Evidence suggests that between 40 and 75% of patients discontinue their statin therapy within one year after initiation. Furthermore, whilst the reasons for persistence with statin therapy are complex, evidence shows that low-adherence to statins negatively impacts clinical outcomes and residual CV risk remains a major concern. Non-adherence or lack of persistence with long-term statin therapy in real-life may be the main cause of inadequate low density lipoprotein cholesterol lowering with statins. There is a large need for the improvement of the use of statins, which have good safety profiles and are inexpensive. On the other hand, in a non-cost-constrained environment, proprotein convertase subtilisin/kexin type 9 inhibitors should arguably be used more often in those patients in whom treatment with statins remains unsatisfactory.

The Use of Oral Disease-Modifying Therapies in Multiple Sclerosis

Three oral disease-modifying drugs-fingolimod, teriflunomide, and dimethyl fumarate (DMF)-are available for treatment of relapsing forms of multiple sclerosis (MS). All three agents were approved in the last decade, primarily on the basis of a moderate to substantial reduction in the occurrence of MS relapses and central nervous system lesion formation detected by MRI. In the trials leading to approval, the first oral disease-modifying drug, fingolimod, reduced the annualized relapse rate (ARR) from 0.40 in placebo-treated patients to 0.18 (FREEDOMS) and from 0.33 in patients treated with interferon β1a intramuscularly to 0.16 (TRANSFORMS). Teriflunomide, approved on the basis of the two placebo-controlled trials TEMSO and TOWER, demonstrated a reduction in the ARR from 0.54 to 0.37 and from 0.50 to 0.32 respectively. The latest oral MS medication, approved in 2014, is DMF, which had been used in a different formulation for treatment of psoriasis for decades. In the 2-year DEFINE study, the proportion of patients with a relapse was reduced to 27 %, compared with 46 % in placebo arm, whereas in the CONFIRM trial, the ARR was reduced from 0.40 (placebo) to 0.22 in the DMF-treated group of patients. In this review, we will elucidate the mechanisms of action of these three medications and compare their efficacy, safety, and tolerability as a practical guideline for their use. We will further discuss effects other than relapse reduction these small molecules may exert, including potential activities within the central nervous system, and briefly summarize emerging data on new oral MS drugs in clinical development.

Statins for the treatment of depression: A meta-analysis of randomized, double-blind, placebo-controlled trials

BACKGROUND

In epidemiological studies, statins appear to benefit mood, and there are now some randomized controlled trials examining the efficacy of statins. However, the role of statins in depression remains uncertain. Thus the aim of this paper was to assess the effect of statins on depressive symptoms by performing a meta-analysis of all double-blind, randomized, placebo controlled clinical trials (RCT) conducted in subjects with depression.

METHODS

A systematic search was executed using PubMed and ClinicalTrials.gov in November 30th, 2015 for all double-blind, RCT of statins versus placebo in persons with depressive symptoms. Sixty-seven potential articles were identified through search of electronic databases, of those three met inclusion criteria and were included in the meta-analysis. The outcome measure was change in Hamilton Depression Rating Scale (HDRS) scores associated with statin use. A meta-analysis was conducted and standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated. GRADE was used to assess study quality.

RESULTS

The three articles included provided data on 165 participants with moderate to severe depression. Of these, 82 were randomized to statins as an adjuvant therapy to antidepressant treatment (i.e., citalopram or fluoxetine) and 83 to the placebo arm. All studies were double-blind RCTs, with a follow-up of 6-12 weeks. The statin agents evaluated were lovastatin, atorvastatin, and simvastatin. When compared to placebo, statins, as add-on to treatment as usual, largely improved depressive symptoms as assessed by the HDRS (SMD=-0.73, 95% IC -1.04 to -0.42, p<0.001, 3 between-group comparisons, n=165). No serious adverse effects were reported.

CONCLUSIONS

Our results suggest that adjunctive treatment with statins could be useful for the treatment of depressive symptoms. Additional double-blind, randomised, placebo-controlled trials are necessary to settle the matter.

Management of intracerebral hemorrhage--use of statins

Intracerebral hemorrhage (ICH) is a neurologic injury resulting in significant morbidity and mortality. Statins play a significant role in primary and secondary prevention of cardiovascular and cerebrovascular ischemic events. Despite clear benefits of statins in ischemic stroke, post hoc analyses of some studies suggest there may be a link between statin therapy and development of ICH. Direct pharmacologic effects of decreased serum levels of total cholesterol and low-density lipoproteins in conjunction with pleiotropic effects are thought to be linked to this possible increase in ICH risk. In the face of the potential of statins to increase the risk of ICH, recent evidence suggests that statins may also have beneficial effects on patient outcomes when continued or initiated following an ICH. This discordance in findings and the overall lack of well-designed prospective clinical trials increase the complexity of clinical decision making when utilizing statin therapy in patients with, or at risk for, ICH. This review evaluates the pharmacologic effects of statin therapy and describes how these effects translate to both risks and benefits in ICH. The current literature regarding the effects of statin therapy on clinical outcomes in ICH is evaluated to help guide clinicians with decisions regarding initiation, continuation, or discontinuation of statin therapy in patients with ICH.

Geranylgeraniol and Neurological Impairment: Involvement of Apoptosis and Mitochondrial Morphology

Deregulation of the cholesterol pathway is an anomaly observed in human diseases, many of which have in common neurological involvement and unknown pathogenesis. In this study we have used Mevalonate Kinase Deficiency (MKD) as a disease-model in order to investigate the link between the deregulation of the mevalonate pathway and the consequent neurodegeneration. The blocking of the mevalonate pathway in a neuronal cell line (Daoy), using statins or mevalonate, induced an increase in the expression of the inflammasome gene (NLRP3) and programmed cell death related to mitochondrial dysfunction. The morphology of the mitochondria changed, clearly showing the damage induced by oxidative stress and the decreased membrane potential associated with the alterations of the mitochondrial function. The co-administration of geranylgeraniol (GGOH) reduced the inflammatory marker and the damage of the mitochondria, maintaining its shape and components. Our data allow us to speculate about the mechanism by which isoprenoids are able to rescue the inflammatory marker in neuronal cells, independently from the block of the mevalonate pathway, and about the fact that cell death is mitochondria-related.

Statins for the prevention of dementia

BACKGROUND

This is an update of a Cochrane review first published in 2001 and then updated in 2009. Vascular risk factors including high cholesterol levels increase the risk of dementia due to Alzheimer's disease and of vascular dementia. Some observational studies have suggested an association between statin use and lowered incidence of dementia.

OBJECTIVES

To evaluate the efficacy and safety of statins for the prevention of dementia in people at risk of dementia due to their age and to determine whether the efficacy and safety of statins for this purpose depends on cholesterol level, apolipoprotein E (ApoE) genotype or cognitive level.

SEARCH METHODS

We searched ALOIS (the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS, ClinicalTrials.gov and the World Health Organization (WHO) Portal on 11 November 2015.

SELECTION CRITERIA

We included double-blind, randomised, placebo-controlled trials in which statins were administered for at least 12 months to people at risk of dementia.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included two trials with 26,340 participants aged 40 to 82 years of whom 11,610 were aged 70 or older. All participants had a history of, or risk factors for, vascular disease. The studies used different statins (simvastatin and pravastatin). Mean follow-up was 3.2 years in one study and five years in one study. The risk of bias was low. Only one study reported on the incidence of dementia (20,536 participants, 31 cases in each group; odds ratio (OR) 1.00, 95% confidence interval (CI) 0.61 to 1.65, moderate quality evidence, downgraded due to imprecision). Both studies assessed cognitive function, but at different times using different scales, so we judged the results unsuitable for a meta-analysis. There were no differences between statin and placebo groups on five different cognitive tests (high quality evidence). Rates of treatment discontinuation due to non-fatal adverse events were less than 5% in both studies and there was no difference between statin and placebo groups in the risk of withdrawal due to adverse events (26,340 participants, 2 studies, OR 0.94, 95% CI 0.83 to 1.05).

AUTHORS' CONCLUSIONS

There is good evidence that statins given in late life to people at risk of vascular disease do not prevent cognitive decline or dementia. Biologically, it seems feasible that statins could prevent dementia due to their role in cholesterol reduction and initial evidence from observational studies was very promising. However, indication bias may have been a factor in these studies and the evidence from subsequent RCTs has been negative. There were limitations in the included studies involving the cognitive assessments used and the inclusion of participants at moderate to high vascular risk only.

Atorvastatin protects endothelial colony‑forming cells against H2O2‑induced oxidative damage by regulating the expression of annexin A2

Endothelial dysfunction and injury are central events in the pathogenesis of ischemic vascular disorders. Endothelial progenitor cells (EPCs) are mobilized from the bone marrow into the peripheral circulation, where they locate to sites of injured endothelium and are involved in endothelial repair and vascular regeneration. During these processes, EPCs are exposed to oxidative stress, a crucial pathological condition, which occurs during vascular injury and limits the efficacy of EPCs in the repair of injured endothelium. Statins are effective inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, and are commonly used to manage and prevent ischemic vascular disease by reducing plasma cholesterol levels. In addition to lowering cholesterol, statins have also been reported to exert pleiotropic actions, including anti-inflammatory and anti-oxidative activities. The present study aimed to investigate the ability of atorvastatin to protect endothelial colony-forming cells (ECFCs), a homogeneous subtype of EPCs, from hydrogen peroxide (H₂O₂)-induced oxidative damage, and to determine the mechanism underlying this protective action. MTT assay, acridine orange/ethidium bromide staining, reactive oxygen species assay, western blot analysis and tube formation assay were employed. The results demonstrated that H₂O₂ induced cell death and decreased the tube-forming ability of the ECFCs, in a concentration-dependent manner; however, these effects were partially attenuated following administration of atorvastatin. The reversion of the quantitative and qualitative impairment of the H₂O₂-treated ECFCs appeared to be mediated by the regulation of annexin A2, as the expression levels of annexin A2 were decreased following treatment with H₂O₂ and increased following treatment with atorvastatin. These results indicated that annexin A2 may be involved in the H₂O₂-induced damage of ECFCs, and in the protective activities of atorvastatin in response to oxidative stress.

Efficacy of atorvastatin on hippocampal neuronal damage caused by chronic intermittent hypoxia: Involving TLR4 and its downstream signaling pathway

Hippocampal neuronal damage is critical for the initiation and progression of neurocognitive impairment accompanied obstructive sleep apnea syndrome (OSAS). Toll-like receptor 4 (TLR4) plays an important role in the development of several hippocampus-related neural disorders. Atorvastatin was reported beneficially regulates TLR4. Here, we examined the effects of atorvastatin on hippocampal injury caused by chronic intermittent hypoxia (CIH), the most characteristic pathophysiological change of OSAS. Mice were exposed to intermittent hypoxia with or without atorvastatin for 4 weeks. Cell damage, the expressions of TLR4 and its two downstream factors myeloid differentiation factor 88 (MYD88) and TIR-domain-containing adapter-inducing interferon-β (TRIF), inflammatory agents (tumor necrosis factor α and interleukin 1β), and the oxidative stress (superoxide dismutase and malondialdehyde) were determined. Atorvastatin decreased the neural injury and the elevation of TLR4, MyD88, TRIF, pro-inflammatory cytokines and oxidative stress caused by CIH. Our study suggests that atorvastatin may attenuate CIH induced hippocampal neuronal damage partially via TLR4 and its downstream signaling pathway.