Neuroprotective effects of statins may not be related to total and low-density lipoprotein cholesterol lowering

Associations of dyslipidaemia and lipid-lowering treatment with risk of postoperative cognitive dysfunction: a systematic review and meta-analysis

BACKGROUND

Lipid imbalance is linked to age-related cognitive impairment, but its role in postoperative cognitive dysfunction (POCD) is unknown. Here, we present a systematic review and meta-analysis on dyslipidaemia, lipid-lowering treatment and POCD risk.

METHODS

PubMed, Ovid SP and Cochrane databases were searched for longitudinal studies that reported on associations of any measure of dyslipidaemia and/or lipid-lowering treatment with POCD as relative risks (RRs) or ORs. Fixed-effects inverse variance models were used to combine effects.

RESULTS

Of 205 articles identified in the search, 17 studies on 2725 patients (grand mean age 67 years; mean age range 61-71 years) with follow-up periods of 1 day to 4 years (median 7 days; IQR 1-68 days) were included. Studies focused almost exclusively on hypercholesterolaemia as a measure of dyslipidaemia and on statins as lipid-lowering treatment. Across 12 studies on hypercholesterolaemia, we found no association with POCD risk (RR 0.93; 95% CI 0.80 to 1.08; P=0.34). Statin use before surgery was associated with a reduced POCD risk across eight studies (RR 0.81; 95% CI 0.67 to 0.98; P=0.03), but data on treatment duration were lacking.

CONCLUSION

Statin users appear to be at reduced risk of POCD although hypercholesterolaemia per se may not be associated with POCD risk. Trial studies are needed to evaluate the usefulness of statins in POCD prevention.

Enhanced oxidative stress response and neuroprotection of combined limb remote ischemic conditioning and atorvastatin after transient ischemic stroke in rats

BACKGROUND:

Limb remote ischemic conditioning (LRIC) and atorvastatin (AtS) both provide neuroprotection in stroke. We evaluated the enhanced neuroprotective effect of combining these two treatments in preventing ischemia/reperfusion (I/R)-induced cerebral injury in a rat model and investigated the corresponding molecular mechanisms.

MATERIALS AND METHODS:

Transient cerebral ischemia was induced in Sprague–Dawley male rats by middle cerebral artery occlusion (MCAO) for 90 min followed by reperfusion (I/R). Rats were divided into 5 groups, sham, I/R, I/R + AtS, I/R + LRIC and I/R + AtS + LRIC. Pretreatment with LRIC and/or AtS for 14 days before MCAO surgery. Infarct volume, neurological score, Western blot, immuno-histochemical analyses were performed.

RESULTS:

The combination of LRIC plus AtS pretreatment decreased infarct volume and inhibited neuronal apoptosis. Combination treatment achieved stronger neuroprotection than monotherapy with LRIC or AtS. These therapies reduced reactive oxygen species production in the peri-ischemia region, associated with significantly increased expression and activation of superoxide dismutase 1, hemeoxygenase 1 and nuclear factor erythroid 2-related factor 2.

CONCLUSIONS:

Both LRIC and AtS + LRIC treatments conferred neuroprotection in ischemic stroke by reducing brain oxidative stress. AtS plus LRIC is an attractive translational research option due to its ease of use, tolerability, economical, and tremendous neuroprotective potential in stroke.

Lovastatin modulates glycogen synthase kinase-3β pathway and inhibits mossy fiber sprouting after pilocarpine-induced status epilepticus

This study was undertaken to assay the effect of lovastatin on the glycogen synthase kinase-3 beta (GSK-3β) and collapsin responsive mediator protein-2 (CRMP-2) signaling pathway and mossy fiber sprouting (MFS) in epileptic rats. MFS in the dentate gyrus (DG) is an important feature of temporal lobe epilepsy (TLE) and is highly related to the severity and the frequency of spontaneous recurrent seizures. However, the molecular mechanism of MFS is mostly unknown. GSK-3β and CRMP-2 are the genes responsible for axonal growth and neuronal polarity in the hippocampus, therefore this pathway is a potential target to investigate MFS. Pilocarpine-induced status epilepticus animal model was taken as our researching material. Western blot, histological and electrophysiological techniques were used as the studying tools. The results showed that the expression level of GSK-3β and CRMP-2 were elevated after seizure induction, and the administration of lovastatin reversed this effect and significantly reduced the extent of MFS in both DG and CA3 region in the hippocampus. The alteration of expression level of GSK-3β and CRMP-2 after seizure induction proposes that GSK-3β and CRMP-2 are crucial for MFS and epiletogenesis. The fact that lovastatin reversed the expression level of GSK-3β and CRMP-2 indicated that GSK-3β and CRMP-2 are possible to be a novel mechanism of lovatstain to suppress MFS and revealed a new therapeutic target and researching direction for studying the mechanism of MFS and epileptogenesis.

Evidence for the efficacy of statins in animal stroke models: a meta-analysis

Protective effects of statins have been well documented for stroke therapy. Here, we used a systematic review and meta-analysis to assess these evidences. We identified 190 studies using statin treatment in stroke animal models by electronic searching. From those, only studies describing ischemic occlusive stroke and reporting data on infarct volume and/or neurological outcome were included in the analysis (41 publications, 1882 animals). The global estimate effect was assessed by Weighted Mean Difference meta-analysis. Statins reduced infarct volume by 25.12% (20.66%-29.58%, P < 0.001) and consistently, induced an improvement on neurological outcome (20.36% (14.17%-26.56%), P < 0.001). Stratified analysis showed that simvastatin had the greatest effect on infarct volume reduction (38.18%) and neurological improvement (22.94%), whereas bigger infarct reduction was observed giving the statin as a pre-treatment (33.5%) compared with post-treatment (16.02%). The use of pentobarbital sodium, the timing of statin administration, the statement of conflict of interest and the type of statin studied were found to be independent factors in the meta-regression, indicating their influence on the results of studies examining statin treatment. In conclusion, this meta-analysis provides further evidences of the efficacy of statins, supporting their potential use for human stroke therapy.

Statin use before and after acute ischemic stroke onset improves neurological outcome

The devastating consequences of stroke, both in terms of morbidity and mortality, and the economic implications it has worldwide, coupled with a growing knowledge regarding its pathophysiology, has led to the development of novel therapeutic strategies in recent years that have had an enormous impact on clinical practice and the outcome of stroke patients. While thrombolysis is regarded as the most important of these developments, its relatively narrow therapeutic window and complexity of administration imply that only a minority of stroke patients can benefit from it. Among other strategies, in an attempt to overcome this limitation, research has focused on the development of neuroprotection aimed to salvage ischemic brain tissue by means complementary to reperfusion. Among these approaches, the use of statins stands out, which, by inhibiting the HMG CoA reductase, interfere with the formation of isoprenoid intermediates in the biosynthesis of cholesterol, and have been shown to have a positive impact in both the incidence and outcome of acute stroke. The main results of animal models, observational studies, clinical trials and opinion articles available in the medical literature covering the effect of statins on acute brain ischemia will be reviewed in order to provide in-depth information regarding their mode of action and current evidence regarding their potential benefits for ischemic stroke patients.

Lower low-density lipoprotein cholesterol levels are associated with Parkinson's disease

The apolipoprotein E (APOE) epsilon2 allele has been associated with both Parkinson's disease (PD) and lower low-density lipoprotein cholesterol (LDL-C). We tested the hypothesis that lower LDL-C may be associated with PD. This case-control study used fasting lipid profiles obtained from 124 PD cases and 112 controls. The PD cases were recruited from consecutive cases presenting at our tertiary Movement Disorder Clinic, and the controls were recruited from the spouse populations of the same clinic. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) were calculated from unconditional logistic regressions, adjusting for age, gender, smoking status, and use of cholesterol-lowering agents. Lower LDL-C concentrations were associated with a higher occurrence of PD. Compared with participants with the highest LDL-C (> or =138 mg/dL), the OR was 2.2 (95% CI = 0.9-5.1) for participants with LDL-C of 115 to 137, 3.5 (95% CI = 1.6-8.1) for LDL-C of 93 to 114, and 2.6 (95% CI = 1.1-5.9) for LDL-C of < or = 92. Interestingly, use of either cholesterol-lowering drugs, or statins alone, was related to lower PD occurrence. Thus, our data provide preliminary evidence that low LDL-C may be associated with higher occurrence of PD, and/or that statin use may lower PD occurrence, either of which finding warrants further investigation.

Preoperative Statin Therapy Does Not Reduce Cognitive Dysfunction After Cardiopulmonary Bypass

OBJECTIVE

The purpose of this study was to determine if patients receiving statin therapy before coronary artery bypass grafting surgery would have less cognitive dysfunction after cardiopulmonary bypass as a consequence of a diminished inflammatory response.

DESIGN

Retrospective observational study of patients undergoing coronary artery bypass grafting surgery.

SETTING

Referral center for cardiothoracic surgery at a university hospital.

PARTICIPANTS

Four hundred forty patients undergoing coronary artery bypass grafting surgery with cardiopulmonary bypass.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Thirty-five percent of patients received statins in the preoperative period. Multivariable analysis revealed no effect of preoperative statin therapy on cognitive function (p = 0.67). Post hoc analysis revealed that statin therapy at hospital discharge was associated with less improvement in cognitive performance at 6 weeks after surgery (p = 0.011). No significant differences were found between statin therapy groups in either range or maximum value of any of the cytokines (p > 0.05).

CONCLUSIONS

Preoperative statin therapy did not decrease the inflammatory response to cardiopulmonary bypass or the cognitive dysfunction commonly seen after cardiac surgery.

Pharmacologic Agents in Stroke Prevention, Acute Stroke Therapy, and Interventional Procedures

Pharmaceutical agents have moved far beyond just the aspirin and heparin that were the mainstays of stroke and interventional therapy as recently as 10 to 15 years ago. Our understanding of the mechanisms of thrombus formation and vascular response to damage as well as our armamentarium has tremendously improved in the past decade. Direct thrombin inhibitors, powerful antiplatelet agents, new fibrinolytic agents, and statins now allow far greater manipulation of the intraprocedural and postprocedural clot cascade and atherogenesis. It is mandatory that current-day interventionists understand the correct and appropriate use of these agents to achieve the desired outcomes of therapy.