HMG CoA reductase inhibitors reduce ischemic brain injury of Wistar rats through decreasing oxidative stress on neurons

Statins and angiogenesis in non-cardiovascular diseases

Statins inhibit HMG-CoA reductase by competitively inhibiting the active site of the enzyme, thus preventing cholesterol synthesis and reducing the risk of developing cardiovascular disease. Many pleiotropic effects of statins have been demonstrated that can be either related or unrelated to their cholesterol-lowering ability. Among these effects are their proangiogenic and antiangiogenic properties that could offer new therapeutic applications. In this regard, pro- and anti-angiogenic properties of statins have been shown to be dose dependent. Statins also appear to have a variety of non-cardiovascular angiogenic effects in many diseases, some examples being ocular disease, brain disease, cancer, preeclampsia, diabetes and bone disease, which are discussed in this review using reports from in vitro and in vivo investigations.

Pharmacological Approaches for the Prevention of Breast Implant Capsular Contracture

Capsular contracture is a common complication associated with breast implants following reconstructive or aesthetic surgery in which a tight or constricting scar tissue capsule forms around the implant, often distorting the breast shape and resulting in chronic pain. Capsulectomy (involving full removal of the capsule surrounding the implant) and capsulotomy (where the capsule is released and/or partly removed to create more space for the implant) are the most common surgical procedures used to treat capsular contracture. Various structural modifications of the implant device (including use of textured implants, submuscular placement of the implant, and the use of polyurethane-coated implants) and surgical strategies (including pre-operative skin washing and irrigation of the implant pocket with antibiotics) have been and/or are currently used to help reduce the incidence of capsular contracture. In this article, we review the pharmacological approaches-both commonly practiced in the clinic and experimental-reported in the scientific and clinical literature aimed at either preventing or treating capsular contracture, including (i) pre- and post-operative intravenous administration of drug substances, (ii) systemic (usually oral) administration of drugs before and after surgery, (iii) modification of the implant surface with grafted drug substances, (iv) irrigation of the implant or peri-implant tissue with drugs prior to implantation, and (v) incorporation of drugs into the implant shell or filler prior to surgery followed by drug release in situ after implantation.

Impact of drug treatment and drug interactions in post-stroke epilepsy

Stroke is a huge burden on our society and this is expected to grow in the future due to the aging population and the associated co-morbidities. The improvement of acute stroke care has increased the survival rate of stroke patients, and many patients are left with permanent disability, which makes stroke the main cause of adult disability. Unfortunately, many patients face other severe complications such as post-stroke seizures and epilepsy. Acute seizures (ASS) occur within 1 week after the stroke while later occurring unprovoked seizures are diagnosed as post-stroke epilepsy (PSE). Both are associated with a poor prognosis of a functional recovery. The underlying neurobiological mechanisms are complex and poorly understood. There are no universal guidelines on the management of PSE. There is increasing evidence for several risk factors for ASS/PSE, however, the impacts of recanalization, drugs used for secondary prevention of stroke, treatment of stroke co-morbidities and antiseizure medication are currently poorly understood. This review focuses on the common medications that stroke patients are prescribed and potential drug interactions possibly complicating the management of ASS/PSE.

Statin Therapy in Ischemic Stroke Models: A Meta-Analysis

Statins, drugs known for lipid lowering capabilities and reduction of cardiovascular disease, have demonstrated neuroprotective effects following ischemic stroke in retrospective clinical and animal studies. However, dosing (methods, time, type of statin, and quantity) varies across studies, limiting the clinical applicability of these findings. Furthermore, a comprehensive review of statins in edema and blood-brain barrier (BBB) breakdown is needed to provide insight on diverse, less explored neuroprotective effects. In the present study, we conduct a meta-analysis of publications evaluating statin administration in animal models of ischemic stroke. We review statins' most effective dosing regimen in four outcomes-infarct, edema, BBB breakdown, and functional outcome-to characterize several parameters of benefit associated with statin administration. A search term was constructed to identify experimental murine studies exploring statin use after transient middle cerebral artery occlusion (tMCAO) in PubMed, Web of Science, and Embase. Extracted data included statin type, dose, time and method of administration, and the four predetermined outcomes (functional outcome, edema, BBB breakdown, and infarction). A meta-analysis and stratified meta-regression were conducted using the standardized mean difference (SMD) method for continuous measurements. Included publications were assessed for bias using SYRCLE's RoB tool for animal studies. A total of 24 studies were included. Statin administration significantly reduced infarct volume (p < 0.0001), edema volume (p < 0.002), and neurological deficit (p < 0.0001). Simvastatin and pravastatin were most effective in reducing infarct volume when compared with atorvastatin (p = 0.0475, p = 0.0004) and rosuvastatin (p = 0.0036, p < 0.0001). Pravastatin outperformed all others in functional outcome. Subcutaneous (SC) injection was most effective in all outcomes. Statin therapy reduced BBB breakdown according to our systematic review. Mean study quality was 4.6/10. While statin therapy evidently improves neurological outcome following ischemic stroke, this analysis adds to our understanding of dosing and statins' effects on edema and BBB breakdown. These findings will aid the design of future studies investigating statin use and have larger implications for the clinical care of ischemic stroke patients.

DNA and RNA oxidative damage are associated to mortality in patients with cerebral infarction

OBJECTIVE

Secondary injury due to oxidation may occur during ischemic stroke, possibly leading to oxidative damage to deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Higher blood concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG) (through the oxidation of guanosine from DNA) have been found in ischemic stroke patients than in healthy subjects, and in patients with versus without post-ischemic stroke depression. The present study was carried out to explore the possible association between serum DNA and RNA oxidative damage and mortality in patients with cerebral infarction.

METHODS

A prospective, multicenter observational study was carried out in the Intensive Care Units of 6 Spanish hospitals. We included patients with severe malignant middle cerebral artery infarction (MMCAI) defined as ischemic changes evidenced by computed tomography in more than 50% of the middle cerebral artery territory and a Glasgow Coma Score (GCS)<9. Serum concentrations of the three oxidized guanine species (OGS) (8-hydroxyguanine from DNA or RNA, 8-hydroxyguanosine from RNA, and 8-OHdG from DNA) on the day of MMCAI diagnosis were determined. The study endpoint was 30-day mortality.

RESULTS

We found higher serum OGS levels (p<0.001) in non-surviving (n=34) than in surviving patients (n=34). Logistic regression analyses showed serum OGS levels to be associated to 30-day mortality controlling for lactic acid, GCS and platelet count (OR=1.568; 95%CI=1.131-2.174; p=0.01).

CONCLUSIONS

The novel observation in this study is the association between global serum OGS concentration and mortality in ischemic stroke patients.

Statins and the Brain: More than Lipid Lowering Agents?

BACKGROUND

Statins represent a class of medications widely prescribed to efficiently treat dyslipidemia. These drugs inhibit 3-βhydroxy 3β-methylglutaryl Coenzyme A reductase (HMGR), the rate-limiting enzyme of mevalonate (MVA) pathway. Besides cholesterol, MVA pathway leads to the production of several other compounds, which are essential in the regulation of a plethora of biological activities, including in the central nervous system. For these reasons, statins are able to induce pleiotropic actions, and acquire increased interest as potential and novel modulators in brain processes, especially during pathological conditions.

OBJECTIVE

The purpose of this review is to summarize and examine the current knowledge about pharmacokinetic and pharmacodynamic properties of statins in the brain. In addition, effects of statin on brain diseases are discussed providing the most up-to-date information.

METHODS

Relevant scientific information was identified from PubMed database using the following keywords: statins and brain, central nervous system, neurological diseases, neurodegeneration, brain tumors, mood, stroke.

RESULTS

315 scientific articles were selected and analyzed for the writing of this review article. Several papers highlighted that statin treatment is effective in preventing or ameliorating the symptomatology of a number of brain pathologies. However, other studies failed to demonstrate a neuroprotective effect.

CONCLUSION

Even though considerable research studies suggest pivotal functional outcomes induced by statin therapy, additional investigation is required to better determine the pharmacological effectiveness of statins in the brain, and support their clinical use in the management of different neuropathologies.

Simvastatin improves cerebrovascular injury caused by ischemia‑reperfusion through NF‑κB‑mediated apoptosis via MyD88/TRIF signaling

Cerebrovascular injury is the most prevalent human cerebrovascular disease and frequently results in ischemic stroke. Simvastatin may be a potential therapeutic agent for the treatment of patients with cerebrovascular injury. The present study aimed to investigate the efficacy of and the potential mechanisms regulated by simvastatin in a rat model of ischemia-reperfusion (I/R)-induced cerebrovascular injury. Cerebrovascular injury model rats were established and were subsequently treated with simvastatin or a vehicle control following I/R injury. Cell damage, neurological functions and neuronal apoptosis were examined, as well as the nuclear factor (NF)-κB-mediated myeloid differentiation primary response protein 88 (MyD88)/toll-interleukin-1 receptor domain-containing adapter molecule 1 (TRIF) signaling pathway following simvastatin treatment. The results of the present study demonstrated that simvastatin treatment led to a reduction in cell damage, improvement of neurological functions and decreased neuronal apoptosis compared with vehicle-treated I/R model rats, 14 days post-treatment. In addition, simvastatin treatment reduced cerebral water content and blood-brain barrier disruption in cerebrovascular injury induced by I/R. The results also revealed that simvastatin treatment inhibited neuronal apoptosis via the NF-κB-mediated MyD88/TRIF signaling pathway. In conclusion, simvastatin treatment may reduce I/R-induced neuronal apoptosis via inhibition of the NF-κB-mediated MyD88/TRIF signaling pathway.

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.

Simvastatin protects ischemic spinal cord injury from cell death and cytotoxicity through decreasing oxidative stress: in vitro primary cultured rat spinal cord model under oxygen and glucose deprivation-reoxygenation conditions

Background

Ischemia and the following reperfusion damage are critical mechanisms of spinal cord injury. Statins have been reported to decrease ischemia–reperfusion injury in many organs including the spinal cord. Anti-oxidative effect is one of the main protective mechanisms of statin against neuronal death and cytotoxicity. We hypothesized that statins’ anti-oxidative property would yield neuroprotective effects on spinal cord ischemia–reperfusion injury

Methods

Primary cultured spinal cord motor neurons were isolated from Sprague–Dawley rat fetuses. Ischemia–reperfusion injury model was induced by 60 min of oxygen and glucose deprivation (OGD) and 24 h of reoxygenation. Healthy and OGD cells were treated with simvastatin at concentrations of 0.1, 1, and 10 μM for 24 h. Cell viability was assessed using water-soluble tetrazolium salt (WST)-8, cytotoxicity with LDH, and production of free radicals with DCFDA (2′,7′-dichlorofluorescein diacetate).

Results

OGD reduced neuronal viability compared to normoxic control by 35.3%; however, 0.1–10 μM of simvastatin treatment following OGD improved cell survival. OGD increased LDH release up to 214%; however, simvastatin treatment attenuated its cytotoxicity at concentrations of 0.1–10 μM (p < 0.001 and p = 0.001). Simvastatin also reduced deteriorated morphological changes of motor neurons following OGD. Oxidative stress was reduced by simvastatin (0.1–10 μM) compared to untreated cells exposed to OGD (p < 0.001).

Conclusions

Simvastatin effectively reduced spinal cord neuronal death and cytotoxicity against ischemia–reperfusion injury, probably via modification of oxidative stress.

Cerebral Small Vessel Disease: Targeting Oxidative Stress as a Novel Therapeutic Strategy?

Cerebral small vessel disease (SVD) is a major contributor to stroke, and a leading cause of cognitive impairment and dementia. Despite the devastating effects of cerebral SVD, the pathogenesis of cerebral SVD is still not completely understood. Moreover, there are no specific pharmacological strategies for its prevention or treatment. Cerebral SVD is characterized by marked functional and structural abnormalities of the cerebral microcirculation. The clinical manifestations of these pathological changes include lacunar infarcts, white matter hyperintensities, and cerebral microbleeds. The main purpose of this review is to discuss evidence implicating oxidative stress in the arteriopathy of both non-amyloid and amyloid (cerebral amyloid angiopathy) forms of cerebral SVD and its most important risk factors (hypertension and aging), as well as its contribution to cerebral SVD-related brain injury and cognitive impairment. We also highlight current evidence of the involvement of the NADPH oxidases in the development of oxidative stress, enzymes that are a major source of reactive oxygen species in the cerebral vasculature. Lastly, we discuss potential pharmacological strategies for oxidative stress in cerebral SVD, including some of the historical and emerging NADPH oxidase inhibitors.

Simvastatin versus atorvastatin for improving mild to moderate depression in post-coronary artery bypass graft patients: A double-blind, placebo-controlled, randomized trial

BACKGROUND

A decreased risk of developing depression has been reported among statin users. Aside from their lipid-lowering effects, statins are considered immunomodulatory agents and have protective effects against oxidative stress and inflammation which are well known for their association with depression. The aim of the present study was to compare the probable antidepressant effects of simvastatin and atorvastatin among post-coronary artery bypass graft (CABG) surgery patients with high and low potentials for blood-brain-barrier penetration, respectively.

METHOD

Forty-six outpatients who had undergone CABG in the last 6 months and suffered from mild to moderate depression participated in a parallel, double-blind, placebo-controlled trial, and were randomized to undergo 6 weeks of treatment with either simvastatin (20mg/day) or atorvastatin (20mg/day). Participants were evaluated using Hamilton depression rating scale (HDRS) at baseline and weeks 3 and 6. The primary outcome was to evaluate the efficacy of simvastatin in improving the depressive symptoms.

RESULT

General linear model repeated measures demonstrated significant effect for time×treatment interaction on the HDRS scores [F (1.62, 71.06)=3.41, P=0.048]. There was no significant difference between the treatment groups regarding the adverse events. No one experienced serious adverse event.

LIMITATION

The limitations of the present study were its small sample size and the short-term follow-up period.

CONCLUSION

Treatment with simvastatin seems to be well tolerated with superior antidepressant effects compared to atorvastatin in post-CABG patients. Long-term outcomes of this practice and its probable influence on other psychological aspects are yet to be investigated in future studies.

TRIAL REGISTRATION

Iranian registry of clinical trials (http://www.irct.ir): IRCT201410271556N68.

Pathophysiology and Treatments of Oxidative Injury in Ischemic Stroke: Focus on the Phagocytic NADPH Oxidase 2

SIGNIFICANCE

Phagocytes play a key role in promoting the oxidative stress after ischemic stroke occurrence. The phagocytic NADPH oxidase (NOX) 2 is a membrane-bound enzyme complex involved in the antimicrobial respiratory burst and free radical production in these cells.

RECENT ADVANCES

Different oxidants have been shown to induce opposite effects on neuronal homeostasis after a stroke. However, several experimental models support the detrimental effects of NOX activity (especially the phagocytic isoform) on brain recovery after stroke. Therapeutic strategies selectively targeting the neurotoxic ROS and increasing neuroprotective oxidants have recently produced promising results.

CRITICAL ISSUES

NOX2 might promote carotid plaque rupture and stroke occurrence. In addition, NOX2-derived reactive oxygen species (ROS) released by resident and recruited phagocytes enhance cerebral ischemic injury, activating the inflammatory apoptotic pathways. The aim of this review is to update evidence on phagocyte-related oxidative stress, focusing on the role of NOX2 as a potential therapeutic target to reduce ROS-related cerebral injury after stroke.

FUTURE DIRECTIONS

Radical scavenger compounds (such as Ebselen and Edaravone) are under clinical investigation as a therapeutic approach against stroke. On the other hand, NOX inhibition might represent a promising strategy to prevent the stroke-related injury. Although selective NOX inhibitors are not yet available, nonselective compounds (such as apocynin and fasudil) provided encouraging results in preclinical studies. Whereas additional studies are needed to better evaluate this therapeutic potential in human beings, the development of specific NOX inhibitors (such as monoclonal antibodies, small-molecule inhibitors, or aptamers) might further improve brain recovery after stroke.

Hepatic ischemia/reperfusion injury is diminished by atorvastatin in Wistar rats

BACKGROUND AND AIMS

Temporal occlusion of the hepatoduodenal ligament (HDL) is often used during liver surgeries in order to reduce blood loss, resulting in ischemia/reperfusion injury (I/R). The aim of the study was to investigate the effects of atorvastatin (ATOR) on hepatic I/R injury and on serum levels of tumor necrosis factor-alpha (TNF-α), endothelin-1 (ET-1), antithrombin III (ATIII) and intracellular adhesion molecule-1 (ICAM-1).

METHODS

Liver ischemia was induced in Wistar rats by clamping the HDL for 60 min, followed by either 60 or 180 min reperfusion. Rats received either vehicle or 10 mg/kg ATOR before hepatic I/R. Control group received sham surgery. Livers were examined for histological damage and serum AST, ALT, TNF-α, ET-1, ATIII and ICAM-1 concentrations were measured.

RESULTS

After I/R, AST and ALT were significantly elevated, ATIII levels were significantly depleted, both TNF-α and ICAM-1 levels increased and ET-1 was significantly elevated (at 180 min). ATOR pretreatment attenuated these alterations and diminished histological injury scores.

CONCLUSIONS

Our results show that ATOR protects the liver from I/R injury.

Effects of atorvastatin and insulin in vascular dysfunction associated with type 2 diabetes

Atorvastatin and insulin have distinct mechanisms of action to improve endothelial function. Therefore, we hypothesized that atorvastatin and insulin therapies alone or in combination could have beneficial effects on endothelium-dependent vascular reactivity, oxidative stress, inflammation and metabolic parameters in Goto-Kakizaki (GK) rats, a model of type 2 diabetes fed with atherogenic diet (GKAD). In parallel with the development of diabetes and lipid profile, the generation of oxidative stress was determined by measurement of lipid peroxides and oxidized proteins and the presence of inflammation was evaluated by assessing C-reactive protein (CRP). Additionally, endothelial dependent and independent vascular sensitivity to acetylcholine and sodium nitroprusside were evaluated. GKAD showed increased carbonyl stress, inflammation, fasting glycemia, dyslipidemia and endothelial dysfunction when compared to control GK rats. Noteworthy, supplementation with insulin deteriorated endothelial dysfunction while atorvastatin induced an improvement. Atorvastatin and insulin therapies in combination improved metabolic parameters, CRP levels and insulin resistance indexes and ameliorated endothelial dysfunction in GKAD rats while they were unable to reduce urinary 8-isoprostranes and plasma carbonyl compounds. The therapeutic association of atorvastatin and insulin provided a better metabolic control with a reduction in endothelial dysfunction in GKAD rats by a mechanism that involves an improvement in systemic inflammation.

Continuous oral administration of atorvastatin ameliorates brain damage after transient focal ischemia in rats

AIMS

Pre-treatment with statins is known to ameliorate ischemic brain damage after experimental stroke, and is independent of cholesterol levels. We undertook pre- vs post-ischemic treatment with atorvastatin after focal cerebral ischemia in rats.

MAIN METHODS

Male Sprague-Dawley rats underwent transient 90-min middle cerebral artery occlusion (MCAO). Atorvastatin (20mg/kg/day) or vehicle was administered orally. Rats were divided into vehicle-treated, atorvastatin pre-treatment, atorvastatin post-treatment, and atorvastatin continuous-treatment groups. In the pre-treatment, rats were given atorvastatin or vehicle for 7 days before MCAO. In the post-treatment, rats received atorvastatin or vehicle for 7 days after MCAO. Measurement of infarct volume, as well as neurological and immunohistochemical assessments, were done 24h and 7 days after reperfusion.

KEY FINDINGS

Each atorvastatin-treated group demonstrated significant reductions in infarct and edema volumes compared with the vehicle-treated group 24h after reperfusion. Seven days after reperfusion, infarct volumes in the post-treatment group and continuous-treatment group (but not the pre-treatment group) were significantly smaller than in the vehicle-treated group. Only the continuous-treatment group had significantly improved neurological scores 7 days after reperfusion compared with the vehicle group. Post-treatment and continuous-treatment groups had significantly decreased lipid peroxidation, oxidative DNA damage, microglial activation, expression of tumor necrosis factor-alpha, and neuronal damage in the cortical ischemic boundary area after 7 days of reperfusion.

SIGNIFICANCE

These results suggest that continuous oral administration (avoiding withdrawal) with statins after stroke may reduce the extent of post-ischemic brain damage and improve neurological outcome by inhibiting oxidative stress and inflammatory responses.

Combining statins with tissue plasminogen activator treatment after experimental and human stroke: a safety study on hemorrhagic transformation

AIMS

Statins may afford neuroprotection against ischemic injury, but it remains controversial whether combined treatment with tissue plasminogen activator (tPA) after stroke increases the risk of hemorrhagic transformation (HT), the major tPA-related complication. We evaluated the safety of combining statin with tPA administration during the acute phase of both experimental and human stroke.

METHODS

The occurrence and severity of HT, infarct volume, and neurological outcome were evaluated in spontaneous hypertensive rats (SHR) subjected to embolic middle cerebral arterial occlusion (MCAO), which received vehicle or simvastatin (20 mg/kg), 15 min after ischemia and tPA (9 mg/kg) 3 h after ischemia. Additionally, HT rate was evaluated in stroke patients who were treated with tPA (0.9 mg/kg) within 3 h after symptom onset, considering whether or not were under statins treatment when the stroke occurred.

RESULTS

In the experimental study, no differences in HT rates and severity were found between treatment groups, neither regarding mortality, neurological deficit, infarct volume, or metalloproteinases (MMPs) brain content. In the clinical study, HT rates and hemorrhage type were similar in stroke patients who were or not under statins treatment.

CONCLUSION

This study consistently confirms that the use of statins does not increase HT rates and severity when is combined with tPA administration.

Valproic acid attenuates ischemia-reperfusion injury in the rat brain through inhibition of oxidative stress and inflammation

Valproic acid (VPA), widely used in clinical contexts for the treatment of seizures and bipolar mood disorder, has neuroprotective properties in cellular and animal models. However, the precise mechanisms underlying its neuroprotection against stroke remain unknown. In the present study, we explored the effect of VPA on experimental ischemic stroke. Male Sprague-Dawley rats were subjected to middle cerebral artery occlusion for 90 min, followed by reperfusion. The animals received a single injection of VPA (300 mg/kg) immediately, 90, or 270 min after the induction of ischemia. Vehicle-treated animals underwent the same procedure with physiological saline. Infarct volume and neurological symptoms were evaluated 24 h after reperfusion. Immunohistochemical staining for myeloperoxidase (MPO), microglia (Iba1), 4-hydroxy-2-nonenal (4-HNE), or 8-hydroxy-deoxyguanosine (8-OHdG) was performed. Ischemic boundary zone cell death was determined by TUNEL staining. VPA injected immediately or 90 min after ischemia induction significantly reduced infarct volume and improved neurological deficit compared with vehicle (P<0.05). VPA was ineffective when given 270 min after ischemia induction. VPA significantly reduced TUNEL-positive cells, MPO-positive cells, Iba1-positive cells, 4-HNE-positive cells, and 8-OHdG-positive cells compared with vehicle in the ischemic boundary zone (P<0.05). The therapeutic time window for single injection of VPA is between 0 and 90 min in this model. Our results demonstrate that single injection of VPA may have anti-inflammatory as well as antioxidative effects, leading to reduced cell death in ischemia-reperfusion injury.

Endoplasmic reticulum dysfunction in neurological disease

Endoplasmic reticulum (ER) dysfunction might have an important part to play in a range of neurological disorders, including cerebral ischaemia, sleep apnoea, Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis, the prion diseases, and familial encephalopathy with neuroserpin inclusion bodies. Protein misfolding in the ER initiates the well studied unfolded protein response in energy-starved neurons during stroke, which is relevant to the toxic effects of reperfusion. The toxic peptide amyloid β induces ER stress in Alzheimer's disease, which leads to activation of similar pathways, whereas the accumulation of polymeric neuroserpin in the neuronal ER triggers a poorly understood ER-overload response. In other neurological disorders, such as Parkinson's and Huntington's diseases, ER dysfunction is well recognised but the mechanisms by which it contributes to pathogenesis remain unclear. By targeting components of these signalling responses, amelioration of their toxic effects and so the treatment of a range of neurodegenerative disorders might become possible.

Anti-inflammatory effect of amlodipine plus atorvastatin treatment on carotid atherosclerosis in zucker metabolic syndrome rats

To investigate the effects of amlodipine in combination with atorvastatin on carotid atherosclerotic changes in metabolic syndrome, 8-week-old Zucker fatty rats were treated with vehicle, amlodipine, atorvastatin, or amlodipine in combination with atorvastatin for 28 days. Histological studies of common carotid arteries showed that lipid deposition determined by Sudan III staining was significantly reduced in rats treated with amlodipine or atorvastatin alone and was further reduced by amlodipine in combination with atorvastatin. Immunohistochemical studies of the pro-inflammatory cytokine tumor necrosis factor (TNF)-α, the arterial calcification initiator bone morphogenetic protein (BMP) 2, the angiogenic factor Notch1, and the smooth muscle cell marker α-smooth muscle actin (SMA) showed that the high expression of all four protein in vehicle-treated rats was greatly decreased by amlodipine, atorvastatin, or amlodipine in combination with atorvastatin, in ascending order. Double immunostaining showed marked colocalization of TNF-α with bone morphogenetic protein 2 and Notch1 with α-SMA in the vehicle group, which was greatly reduced by amlodipine plus atorvastatin. These data suggest that combination therapy may be more effective in preventing atherosclerotic processes and subsequent carotid vascular events than administrating amlodipine or atorvastatin alone in metabolic syndrome.

Pleiotropic effects of pitavastatin

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are established first line treatments for hypercholesterolaemia. In addition to the direct effects of statins in reducing concentrations of atherogenic low density lipoprotein cholesterol (LDL-C), several studies have indicated that the beneficial effects of statins may be due to some of their cholesterol-independent, multiple (pleiotropic) effects which may differ between different members of the class. Pitavastatin is a novel synthetic lipophilic statin that has a number of pharmacodynamic and pharmacokinetic properties distinct from those of other statins, which may underlie its potential pleiotropic benefits in reducing cardiovascular risk factors. This review examines the principal pleiotropic effects of pitavastatin on endothelial function, vascular inflammation, oxidative stress and thrombosis. The article is based on a systematic literature search carried out in December 2010, together with more recent relevant publications where appropriate. The available data from clinical trials and in vitro and animal studies suggest that pitavastatin is not only effective in reducing LDL-C and triglycerides, but also has a range of other effects. These include increasing high density lipoprotein cholesterol, decreasing markers of platelet activation, improving cardiac, renal and endothelial function, and reducing endothelial stress, lipoprotein oxidation and, ultimately, improving the signs and symptoms of atherosclerosis. It is concluded that the diverse pleiotropic actions of pitavastatin may contribute to reducing cardiovascular morbidity and mortality beyond that achieved through LDL-C reduction.

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.

Higher on-admission serum triglycerides predict less severe disability and lower all-cause mortality after acute ischemic stroke

BACKGROUND

High(er) on-admission triglyceride (TG) levels have been suggested as an independent predictor of better outcomes of the acute ischemic stroke. Data regarding poststroke physical disabilities have been contradictory. We aimed to investigate the relationship between fasting on-admission TG and development of disability and all-cause mortality over a 2.5-year period.

METHODS

This prospective observational study included 83 acute ischemic stroke patients (29 cardioembolic; 41% men; median age 76 years) followed-up for 28 to 30 months and assessed for physical disability using the Modified Rankin scale (mRS) at 1 week and 3, 12, and 24 months poststroke. TGs were considered as a continuous and a binary variable (≤ 1.27 [n = 43] and >1.27 mmol/L [n = 43]).

RESULTS

Higher TGs (continuous or binary) were independently (default adjustments: stroke type, severity at presentation, age, atrial fibrillation, preindex event antiplatelet use, infarct volume, postindex event antiplatelet, statin and angiotensin-converting enzyme inhibitor use, on-admission fasting cholesterol, mean platelet volume, and glomerular filtration rate) were associated with: (1) higher odds of mRS 0 to 2 (none/mild disability) across the assessments (overall odds ratio [OR] 2.73 [95% confidence interval {CI} 1.15-6.38] and OR 3.57 [95% CI 1.04-12.3], respectively); (2) lower odds of mRS worsening between any 2 consecutive assessments (overall OR 0.44 [95% CI 0.20-0.96] and OR 0.35 [95% CI 0.16-0.77], respectively); (3) lower risk of all-cause mortality (hazard ratio 0.47 [95% CI 0.23-0.96] and hazard ratio 0.45 [95% CI 0.21-0.98], respectively).

CONCLUSIONS

These data suggest that higher fasting TGs on-admission predict less severe disability, reduced disability progression, and all-cause mortality in patients with acute ischemic stroke.

Effect of pretreatment with simvastatin on spinal cord ischemia-reperfusion injury in rats

OBJECTIVE

The aim of this study was to evaluate the pretreatment effect of simvastatin on spinal cord ischemia-reperfusion injury.

DESIGN

Prospective, interventional study.

SETTING

University research laboratory.

PARTICIPANTS

Forty-five male Sprague-Dawley rats.

INTERVENTIONS

Rats were treated with oral simvastatin, 10 mg/kg (simvastatin group; n = 15) or saline (control group; n = 15) for 5 days before ischemia. Spinal cord ischemia was induced using a balloon-tipped catheter placed in the proximal descending aorta in the control and simvastatin groups, but not in the sham group (n = 15).

MEASUREMENTS AND MAIN RESULTS

Neurologic function was assessed daily using the motor deficit index until 7 days after reperfusion. After the last neurologic evaluation, a histologic examination of the spinal cord was performed. At day 1 after reperfusion, the simvastatin group showed a significantly lower motor deficit index compared with the control group (2.0, 2.0-2.0, v 4.0, 3.5-5.0; p < 0.001). This trend was sustained at day 7 (2.0, 1.5-2.0, v 4.0, 3.0-4.0; p < 0.001). The simvastatin group displayed a significantly larger number of normal motor neurons compared with the control group (mean ± SD, 31.7 ± 6.1 v 20.4 ± 4.4; p < 0.001). However, compared with the sham group, the simvastatin group displayed fewer intact motor neurons (sham group, 38.5 ± 5.1; p = 0.005).

CONCLUSIONS

Pretreatment with simvastatin, 10 mg/kg, given orally for 5 days before the ischemia-reperfusion insult, improved the neurologic outcome and preserved more normal motor neurons compared with the control group in a rat model of spinal cord ischemia-reperfusion.

Simvastatin improves morphological and functional recovery of sciatic nerve injury in Wistar rats

AIM

The purpose of this work is to investigate the effects of simvastatin on sciatic nerve regeneration in male Wistar Rats.

MATERIALS AND METHODS

Forty animals were allocated into four groups: (1) control (C); (2) control+simvastatin (CS); (3) lesioned animals+sterile PBS (LC) and (4) lesioned animals+simvastatin (LS). Lesioned animals were submitted to crushing lesion of right sciatic nerve. Simvastatin (20mg/kg/day, i.p.) was administered for five days. Footprints were obtained weekly for evaluation of functional locomotor recovery by means of the Sciatic Function Index (SFI). Blood samples were obtained weekly for quantifying circulating leukocytes. Animals were sacrificed after 21 days for histological analyses of sciatic nerve and spleen.

RESULTS

LS Animals presented increased SFI scores, decreased areas of oedema and mononuclear cell infiltration during Wallerian degeneration and nerve regeneration (7,14 and 21 days; P<0.05). Spleen weight and white pulp areas was increased in LC animals after 21 days. Increased numbers of circulating neutrophils were observed in simvastatin treated animals (CS e LS) at seven, 14 and 21 days, compared to non-treated groups (C and LC).

CONCLUSION

The study suggests that simvastatin accelerates the morphological and functional recovery process of the peripheral nervous system interfering with innate and acquired immunity.

Osteonecrosis development in a novel rat model characterized by a single application of oxidative stress

OBJECTIVE

To investigate the relationship between transient oxidative stress and the development of osteonecrosis in a rat model.

METHODS

A total of 160 male Wistar rats (24 weeks old) were injected only once with the pro-oxidant DL-buthionine-(S,R)-sulfoximine (BSO) (500 mg/kg given intraperitoneally) and were killed 12 hours (group A), 1 day (group B), 3 days (group C), 4 days (group D), 5 days (group E), 7 days (group F), or 14 days (group G) after administration (n = 20 per group). Twenty untreated rats were used as a control group (group N). Femurs were examined histopathologically for the presence of osteonecrosis, and reduced glutathione (GSH) in liver tissue was measured as an index of oxidative stress.

RESULTS

GSH decreased rapidly after BSO administration. Significant decreases were noted in groups A and B as compared to group N (P < 0.0001 and P = 0.0007, respectively), confirming the development of transient extreme oxidative stress soon after BSO administration. The histopathologic study revealed osteonecrosis in 10% of the rats in group E, 35% of the rats in group F, and 40% of the rats in group G.

CONCLUSION

Transient extreme oxidative stress was confirmed to induce osteonecrosis in this model. Since preparation of this model is extremely simple and because rats are well suited to genetic studies, this model may be of use in elucidating the pathophysiology of femoral head osteonecrosis in future studies.

Reduction of spinal cord ischemia/reperfusion injury with simvastatin in rats

BACKGROUND

Surgery of the thoracic or thoracoabdominal aorta may cause spinal cord ischemia and subsequent paraplegia. However, conventional strategies for preventing paraplegia due to spinal cord ischemia provide insufficient protection and cause additional side effects. We hypothesized that simvastatin, a drug recently shown to be neuroprotective against brain ischemia/reperfusion, would be neuroprotective in a rat spinal cord ischemia/reperfusion model.

METHODS

Rats were randomly assigned to simvastatin, vehicle, or sham-surgery (sham) groups (n = 6 per group). Simvastatin (10 mg/kg) or vehicle was administered subcutaneously once daily for 7 days before aortic balloon occlusion, and once at 24 hours after reperfusion. Spinal cord ischemia was induced by balloon inflation of a 2F Fogarty catheter in the thoracic aorta, and the proximal mean arterial blood pressure was maintained at 40 mm Hg for 12 minutes. The sham group received the same operation without inflation of the balloon. Ischemic injury was assessed by hindlimb motor function using the Motor Deficit Index score at 6 to 48 hours after ischemic reperfusion, and histological assessment of the spinal cord was performed 48 hours after reperfusion.

RESULTS

The Motor Deficit Index scores at 24 and 48 hours after reperfusion were significantly improved in the simvastatin group compared with the vehicle group (P = 0.021 and P = 0.023, respectively). Furthermore, there were significantly more normal motor neurons in the simvastatin group than in the vehicle group (P = 0.037). The percentage area of white matter vacuolation was significantly smaller in the simvastatin group than in the vehicle group (P = 0.030).

CONCLUSIONS

Simvastatin treatment can attenuate hindlimb motor dysfunction and histopathological changes in spinal cord ischemia/reperfusion injury in rats.

Protection against ischemic stroke damage by synergistic treatment with amlodipine plus atorvastatin in Zucker metabolic rat

Ischemic stroke is a major neurologic disorder and a leading cause of disability and death in the world. We compared neuroprotective effects of single or combination therapy of amlodipine (AM) and atorvastatin (AT) in such a metabolic syndrome model Zucker rat. The animals were pretreated with vehicle, AM, AT, or the combination of AM plus AT for 28days, and physical and serum parameters were analyzed, then 90min of transient middle cerebral artery occlusion (tMCAO), was performed followed by immunohistochemical analyses at 24h. Without affecting serum levels of lipids, adiponectin, and leptin, the combination therapy of AM plus AT ameliorated the post-ischemic brain weight increase. The single treatment with AM or AT itself exerted neuroprotective effects with reducing inductions of MMP-9 and AT2R, as well as with preserving collagen IV, and the combination therapy of AM plus AT showed a further synergistic benefit against acute ischemic neural damages. Single AT was more protective on these 3 molecules than single AM at this time point of 24h after tMCAO. Thus, the combination therapy with AM plus AT extended the neuroprotectives effect of single treatment with AM or AT on a part of neurovascular unit and a hypertension-related receptor.

Rosuvastatin induces delayed preconditioning against L-glutamate excitotoxicity in cultured cortical neurons

We tested whether rosuvastatin (RST) protected against excitotoxic neuronal cell death in rat primary cortical neuronal cultures. L-glutamate (200 microM, 1h) reduced neuronal viability (% of naive controls, mean+/-SEM, n=8-32, *p<0.05) from 100+/-2% to 60+/-1%*, but pretreatment with RST (0.5 microM, 3 days) increased survival to 88+/-2%*. RST-induced neuroprotection was not affected by co-application with mevalonate (10 microM), although the same dose of mevalonate fully prevented the neurotoxic effects of a high dose (20 microM) of RST. RST (0.5 microM) pretreatment did not affect mitochondrial membrane potential or superoxide anion levels in quiescent neurons. However, RST pretreatment blunted elevations in free intracellular Ca(2+) and reduced increases in superoxide anion levels following glutamate exposure. Manganese superoxide dismutase (SOD), copper-zinc SOD, catalase, and reduced glutathione levels were unaffected by RST pretreatment. In contrast, acute, one time RST application did not affect either baseline or L-glutamate-induced increases in superoxide levels. In summary, three-day RST pretreatment induces resistance to the excitotoxic effect of L-glutamate in cultured neurons apparently by a mechanism that is independent of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibition. The delayed neuroprotection by RST against excitotoxicity does not involve sustained mitochondrial depolarization or superoxide anion production as initiating events, although it is associated with reduced Ca(2+) influx and superoxide anion production upon L-glutamate challenge.

Statins improve visual field alterations related to hypercholesterolemia

OBJECTIVE

To determine whether lipid-lowering treatment with diet or statins would provide beneficial effects on visual field alterations associated with hypercholesterolemia.

METHODS

180 subjects with hypercholesterolemia were randomly assigned to a low fat diet (diet group) or to a low fat diet plus 40 mg/day of pravastatin (pravastatin group). At the beginning of the study and 6 months after the assigned treatment, all subjects underwent a computerized perimetry test and a determination of plasma concentration of glucose, total cholesterol, LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C) and triglycerides.

RESULTS

At 6 months, both groups showed a significant decrease in total cholesterol, LDL-C and triglycerides compared to basal values, and a significant increase in the HDL-C. The pravastatin group had a significantly greater reduction in total cholesterol (-85+/-21 mg/dl) and LDL-C (-86+/-23 mg/dl) than the diet group (-28+/-9 and -28+/-10mg/dl, respectively). All perimetry parameters improved in both groups after the intervention period, although the improvement was greater in the pravastatin group. Using a general linear model, a significant effect of treatment with pravastatin compared to diet was observed in the improvement of all the perimetry parameters, whereas the change in LDL-C concentrations only had a significant effect on the improvement of one of them.

CONCLUSION

In subjects with hypercholesterolemia, the decrease of blood lipids improves visual field parameters. The major beneficial effect noted with pravastatin, compared to diet, suggests that this effect could be due to the lipid-lowering and pleiotropic actions.

Simvastatin induces heme oxygenase-1 expression but fails to reduce inflammation in the capsule surrounding a silicone shell implant in rats

BACKGROUND

Statins are lipid-lowering agents that are widely used in medical practice. Some studies have demonstrated that statins reduce proinflammatory signaling and have antioxidant and anti-inflammatory effects. The inducible heme oxygenase-1 (HO-1) catalyzes the stepwise degradation of heme to produce equimolar quantities of biliverdin, iron, and carbon monoxide; it has also been suggested to promote the important cholesterol-independent cytoprotective action of statins against oxidative insults. However, overexpression of HO-1 may have dual effects under oxidative stress, and the overaccumulation of ferric iron from heme may result in detrimental rather than cytoprotective effects. This study was designed to investigate the effect of a specific statin, simvastatin, and the role of HO-1 on the inflammatory status of the capsule surrounding a silicone shell implant in rats.

METHODS

Sprague-Dawley rats were randomly assigned to different groups according to the indicated implantation time (1 , 2 wk, 1 , 2 , and 3 mo postimplant) and the presence or absence of additional treatment (2 mg/kg oral simvastatin daily and/or 2 mg/kg HO inhibitor zinc protoporphyrin (ZnPP) by intraperitoneal injection daily). The formed de novo capsular tissue around the silicone implant was dissected away at the indicated time of sacrifice for experiments regarding the HO-1 expression and the inflammatory status.

RESULTS

We found a biphasic pattern of inflammation of the capsule with increased production of TNF-α, IL-1β, and COX-2, and activation of NF-κB at 1 wk and again at 1 mo postimplantation. Numerous CD68+monocytes or macrophages were diffusely distributed in the capsule in the early stage but not in the late stage postimplantation. In addition, the implantation procedure induced HO-1 expression, which was significantly up-regulated in the first 2 wk but decreased after 1 mo. Although daily feeding of the rats with simvastatin at 2 mg/kg induced HO-1 expression in the capsule throughout the experimental period, simvastatin treatment failed to reduce the production of TNF-α, IL-1β, and COX-2, or limit NF-κB activation in the early or late stages after implantation. Additionally, simvastatin treatment did not decrease the amount of CD68+cells distributed in the capsule at 1 wk postimplantation. HO-1 up-regulation by simvastatin treatment or down-regulation by additional injection of ZnPP did not demonstrate significant correlation with the inflammatory status of the capsule.

CONCLUSION

Simvastatin failed to reduce inflammation of the capsule surrounding a silicone shell implant. Although simvastatin induced HO-1 expression throughout the experimental time, up-regulated HO-1 expression could not be attributed to the inflammatory status of the capsule.

Atorvastatin prevents hippocampal cell death due to quinolinic acid-induced seizures in mice by increasing Akt phosphorylation and glutamate uptake

Statins are cholesterol-lowering agents due to the inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. Recent studies have shown statins possess pleiotropic effects, which appear to be independent from its cholesterol-lowering action. In this study, we investigated whether atorvastatin would have protective effects against hippocampal cell death promoted by quinolinic acid (QA)-induced seizures in mice. Mice were pretreated with Atorvastatin (1 or 10 mg/kg) or vehicle (saline, 0.9%), orally, once a day for 7 days before the intracerebroventricular (i.c.v.) QA infusion (36.8 nmol/site). Atorvastatin treatment with 1 mg/kg/day did not significantly prevent QA-induced seizures (13.34%). However, administration of atorvastatin 10 mg/kg/day prevented the clonic and/or tonic seizures induced by QA in 29.41% of the mice. Additionally, administration of atorvastatin 10 mg/kg/day significantly prevented QA-induced cell death in the hippocampus. Atorvastatin treatment promoted an increased Akt phosphorylation, which was sustained after QA infusion in both convulsed and non-convulsed mice. Moreover, atorvastatin pretreatment prevented the reduction in glutamate uptake into hippocampal slices induced by QA i.c.v. infusion. These results show that atorvastatin attenuated QA-induced hippocampal cellular death involving the Akt pathway and glutamate transport modulation. Therefore, atorvastatin treatment might be a useful strategy in the prevention of brain injury caused by the exacerbation of glutamatergic toxicity in neurological diseases such as epilepsy.

Molecular analysis of endoplasmic reticulum stress response after global forebrain ischemia/reperfusion in rats: effect of neuroprotectant simvastatin

Simvastatin is a cholesterol-lowering agent whose functional significance and neuroprotective mechanism in ischemic brain injury is not yet solved. The purpose of this study is to evaluate the effect of simvastatin on ischemic brain injury. We examined the endoplasmic reticulum stress response (UPR/unfolded protein response), by measuring the mRNA and protein levels of specific genes such as ATF6, GRP78, and XBP1 after 15 min 4-VO ischemia and different times of reperfusion (1, 3, and 24 h). The results from the group of naïve ischemic rats were compared with results from the group of pre-treated animals with simvastatin. The results of the experiments showed significant increase in all genes at the mRNA level in ischemic phase (about 43% for XBP1, 58% for GRP78, and 39% for ATF6 more than control). The protein level of XBP1 was decreased in pre-treated animals at ischemic phase and first hour of reperfusion (about 15% less), and did not reach control levels. The protein levels of GRP78 were maximal at third hour of reperfusion in statin group with a small decrease at 24 h of reperfusion in both groups. The levels of ATF6 mRNA in statin-treated animals was higher in comparison to non-statin animals at the ischemic phase and the third hour of reperfusion (about 35% higher), which was also translated into the higher protein level. This could indicate that one of the main proteins targeted to enhance neuroprotective effect to ER during the first two hours of reperfusion was ATF6 protein, the levels of which were 60% higher than in non-treated animals. These data suggest that simvastatin, in addition to the proposed neuroprotective effect, exerts a neuroprotective role in the attenuation of ER stress response after acute ischemic/reperfusion insult.

Atorvastatin efficiency after traumatic brain injury in rats

BACKGROUND

The neuroprotective effects of statins possibly depend on their pleiotropic effect such as antioxidative and anti-inflammatory properties. In this study, we have evaluated the efficiency of atorvastatin on brain edema, lipid peroxidation, and ultrastructural changes in TBI animal model.

METHODS

Modified Feeney method has been used for the trauma model in rats. Only craniectomy for group A and trauma after craniectomy for group B was the procedure for animals. For the trauma, rods weighing 24 g were dropped on a foot plate just over the dura. Atorvastatin (1 mg/kg, IP) was administered to the animals in group C after craniectomy and trauma; but on the other hand, animals in group D received only 0.5 mL PEG as the vehicle. Brains were harvested 24 hours after the trauma for the assays of wet-dry weight, lipid peroxidation level, and ultrastructural investigations. Lipid peroxidation levels, TEM, and UNGS were the investigated parameters. The statistical comparisons between the groups were investigated by 1-way ANOVA and post hoc analysis by Duncan and Dunnett T3 test within the groups at the significance level P = .05.

RESULTS

Trauma increased water contents of the brain tissues and lipid peroxidation levels in groups B and D. When compared with the results of group B (brain edema, 84.694% +/- 1.510%; lipid peroxidation, 74.932 +/- 2.491 nmol/g tissue), atorvastatin (1 mg/kg) significantly decreased brain edema (77.362% +/- 1.448%), lipid peroxidation level (58.335 +/- 3.980 nmol/g tissue), and UNGS scores in group C (P < 0.05).

CONCLUSION

In this descriptive study, the remarkable improvements of atorvastatin on brain edema, lipid peroxidation, and ultrastructural investigations encouraged us for a further dose optimization study.

Statin-induced heme oxygenase-1 increases NF-kappaB activation and oxygen radical production in cultured neuronal cells exposed to lipopolysaccharide

With potentially neuroprotective properties, heme oxygenase-1 (HO-1) has been suggested to be the main mediator of cholesterol-independent anti-inflammatory and antioxidant actions of statins. However, we had demonstrated that simvastatin-induced HO-1 increased apoptosis of Neuro 2A cells in glucose deprivation, and iron production from HO-1 activity may be responsible for the toxicity. This study was designed to explore the effect of simvastatin-induced HO-1 on cultured Neuro 2A and C6 cells exposed to lipopolysaccharide (LPS). We found that the HO-1 upregulation was significantly associated with increased nuclear factor kappa B (NF-kappaB) activation, manifested as IkappaBalpha phosphorylation and p65 nuclear translocation, as well as increased production of superoxides. Inhibition of the induced HO-1 by zinc protoporphyrin reduced the increased NF-kappaB activation and superoxides production. RNA interference with HO-1 siRNA reduced the expression of HO-1 transcripts and protein as well as oxygen radical production. Addition of the iron chelator desferrioxamine to reduce the accumulation of ferric iron from heme by HO-1 resulted in blockade of the aggravated oxygen radical production. There was no significant effect on production of oxygen radicals under these conditions in the presence of a CO donor (RuCO) or a CO scavenger (hemoglobin). In addition, the viable cells were significantly decreased in 48 h in those cells receiving simvastatin pretreatment plus LPS compared to those in control or exposed to simvastatin or LPS alone. This study revealed that simvastatin-induced HO-1 led to increased NF-kappaB activation and superoxides production in the neuronal cells when exposed to LPS, and iron production may play a role in such a response.