The Effect of Statins in Epilepsy: A Systematic Review

Clinical approaches for poststroke seizure: a review

Poststroke seizure is a potential complication of stroke, which is the most frequent acute symptomatic seizure in adults. Patients with stroke may present with an abnormal or aggressive behavior accompanied by altered mental status and symptoms, such as hemiparesis, dysarthria, and sensory deficits. Although stroke manifestations that mimic seizures are rare, diagnosing poststroke seizures can be challenging when accompanied with negative postictal symptoms. Differential diagnoses of poststroke seizures include movement disorders, syncope, and functional (nonepileptic) seizures, which may present with symptoms similar to seizures. Furthermore, it is important to determine whether poststroke seizures occur early or late. Seizures occurring within and after 7 d of stroke onset were classified as early and late seizures, respectively. Early seizures have the same clinical course as acute symptomatic seizures; they rarely recur or require long-term antiseizure medication. Conversely, late seizures are associated with a risk of recurrence similar to that of unprovoked seizures in a patient with a focal lesion, thereby requiring long-term administration of antiseizure medication. After diagnosis, concerns regarding treatment strategies, treatment duration, and administration of primary and secondary prophylaxis often arise. Antiseizure medication decisions for the initiation of short-term primary and long-term secondary seizure prophylaxis should be considered for patients with stroke. Antiseizure drugs such as lamotrigine, carbamazepine, lacosamide, levetiracetam, phenytoin, and valproate may be administered. Poststroke seizures should be diagnosed systematically through history with differential diagnosis; in addition, classifying them as early or late seizures can help to determine treatment strategies.

Analyzing the causal relationship between lipid-lowering drug target genes and epilepsy: a Mendelian randomization study

Background

Previous research has yielded conflicting results on the link between epilepsy risk and lipid-lowering medications. The aim of this study is to determine whether the risk of epilepsy outcomes is causally related to lipid-lowering medications predicted by genetics.

Methods

We used genetic instruments as proxies to the exposure of lipid-lowering drugs, employing variants within or near genes targeted by these drugs and associated with low-density lipoprotein cholesterol (LDL cholesterol) from a genome-wide association study. These variants served as controlling factors. Through drug target Mendelian randomization, we systematically assessed the impact of lipid-lowering medications, including HMG-CoA reductase (HMGCR) inhibitors, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, and Niemann-Pick C1-like 1 (NPC1L1) inhibitors, on epilepsy.

Results

The analysis demonstrated that a higher expression of HMGCR was associated with an elevated risk of various types of epilepsy, including all types (OR = 1.17, 95% CI:1.03 to 1.32, p = 0.01), focal epilepsy (OR = 1.24, 95% CI:1.08 to 1.43, p = 0.003), and focal epilepsy documented with lesions other than hippocampal sclerosis (OR = 1.05, 95% CI: 1.01 to 1.10, p = 0.02). The risk of juvenile absence epilepsy (JAE) was also associated with higher expression of PCSK9 (OR = 1.06, 95% CI: 1.02 to 1.09, p = 0.002). For other relationships, there was no reliable supporting data available.

Conclusion

The drug target MR investigation suggests a possible link between reduced epilepsy vulnerability and HMGCR and PCSK9 inhibition.

Association between statins and the risk of suicide attempt, depression, anxiety, and seizure: A population-based, self-controlled case series study

BACKGROUND

Risk of suicide attempt, depression, anxiety and seizure and the association with statins is an ongoing debate. We aim to investigate the association between statins and the above neuropsychological outcomes, in specific pre- and post-exposure time windows.

METHODS

We identified patients aged 40-75 years old who were dispensed a statin between January 1, 2003 and December 31, 2012 from the Hong Kong Clinical Data Analysis & Reporting System (CDARS), an electronic medical records database. Patients with new onset of suicide attempt, depression, anxiety and seizure were derived from the original dataset separately, in a self-controlled case series study design. A non-parametric spline-based self-controlled case series model was built to measure continuous changes of risk.

RESULTS

We identified 396,614 statin users. The risk of each outcome was elevated prior to statin initiation with incidence rate ratios of 1.38 (95 % CI, 1.09-1.74) for suicide attempt, 1.29 (95 % CI, 1.15-1.45) for depression, 1.35 (95 % CI, 1.19-1.53) for anxiety, and 1.45 (95 % CI, 1.21-1.73) for seizure. The incidence rate ratios remained elevated after the initiation of statins during the first 90 and 91-365 days after statin prescription and decreased to the baseline level after 1 year of continuous prescription.

LIMITATIONS

CDARS includes prescription data but not adherence data, which could lead to misclassification of exposure periods.

CONCLUSIONS

Our study does not support a direct association between statin use and suicide attempt, depression, anxiety and seizure, whose risks could be explained by cardiovascular events, for which statins were prescribed.

Beneficial Effects of Statins on Seizures Independent of Their Lipid-Lowering Effect: A Narrative Review

Among the many types of central nervous system (CNS) disorders, seizures and epilepsy severely affect the quality of life and routine daily activity of the sufferers. We aimed to review research studies that investigated the effect of statins on the prevention and treatment of seizures and epilepsy. Both animal models and human studies were included in this review. This article starts with a brief introduction about seizure, its prevalence, treatment, and various animal models of seizures and epilepsy. Next, we discuss statin's mechanism of action, side effects, and effects on neurological disorders with a specific focus on seizures. Finally, the effects of different types of statins on seizures are compared. The present review gives a better understanding of the therapeutic effects of statins on neurological disorders in animal models and human studies. This permits researchers to set up study designs to resolve current ambiguities and contradictions on the beneficial effects of statins on neurological disorders.

The Clinical Characteristics of New-Onset Epilepsy in the Elderly and Risk Factors for Treatment Outcomes of Antiseizure Medications

Objective

To describe the clinical characteristics of elderly patients with new-onset epilepsy in a Class A tertiary comprehensive hospital in north China and evaluate the treatment outcomes of antiseizure medications (ASMs). This study focuses on investigating the factors affecting the treatment outcomes, guiding the drug treatment, and judging the prognosis of elderly epilepsy patients.

Methods

We included patients aged 60 years or older at the time of their first seizure between January 2014 and August 2020. Demographic characteristics, effects of ASM, and the proportion of 1-year and long-term seizure freedom were reported. The univariate analysis and binary logistic regression were used to identify factors potentially influencing treatment outcomes.

Results

A total of 326 patients (median age 65 years, 67.2% men) were included. Moreover, 185 (56.7%) patients who received the first ASM monotherapy achieved 1 year of seizure freedom in the early stage. Compared with structural etiology, unknown etiology was associated with a higher likelihood of early seizure freedom (odds ratio [OR] = 0.545; p < 0.05). Conversely, comorbid intracranial malignant tumors, taking carbamazepine (CBZ), and sodium valproate (VPA) were associated with a lower likelihood of seizure freedom (OR = 3.527 vs. 6.550 vs. 8.829; p < 0.05). At long-term follow-up, 263 (80.6%) patients achieved seizure freedom, with 79.8% on monotherapy.

Conclusions

Elderly patients with new-onset epilepsy responded well to the initial ASMs treatment. Patients with intracranial malignant tumors and prescribed VPA and CBZ were less likely to achieve early seizure freedom, while those with unknown etiology had higher probabilities of achieving early seizure freedom than those with structural etiology.

Statins for the Prevention of Post-Stroke Seizure and Epilepsy Development: A Systematic Review and Meta-Analysis

OBJECTIVES

Cerebrovascular disease is the leading cause of seizures and incident epilepsy of known etiology in older adults. Statins have increasingly garnered attention as a potential preventive strategy due to their pleiotropic effects beyond lipid-lowering, which may include neuroprotective and anti-epileptogenic properties. We aim to assess the evidence on statin use for prevention of post-stroke early-onset seizures and post-stroke epilepsy.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis in accordance with PRISMA guidelines, which was prospectively registered with PROSPERO (CRD42019144916). PubMed and Embase were searched from database inception to 05/2020 for English-language, full-text studies examining the association between statin use in adults and development of early-onset seizures (≤7 days post-stroke) or post-stroke epilepsy. Pooled analyses were based on random-effects models using the inverse-variance method.

RESULTS

Of 182 citations identified, 175 were excluded due to duplication or ineligibility. The 7 eligible publications were all cohort studies from East Asia or South America, with a total of 53,579 patients. Pre-stroke statin use was not associated with post-stroke epilepsy (3 studies pooled: OR 1.14, CI 0.91-1.42). However, post-stroke statin use was associated with lower risk of both early-onset seizures (3 studies pooled: OR 0.36, CI 0.25-0.53), and post-stroke epilepsy (6 studies pooled: OR 0.64, CI 0.46-0.88).

CONCLUSIONS

Review of 7 cohort studies suggested post-stroke, but not pre-stroke, statin use may be associated with reduced risk of early-onset seizures and post-stroke epilepsy. Further research is warranted to validate these findings in broader populations and better parse the temporal components of the associations.

Effect of acute and chronic exposure to lovastatin on the anticonvulsant action of classical antiepileptic drugs in the mouse maximal electroshock-induced seizure model

Numerous studies indicate neuroprotective activity of statins, commonly used cholesterol lowering drugs in epilepsy and several other neurological diseases. Promising anti-convulsant and neuroprotective effects of statins, attributed to their anti-excitotoxic and anti-inflammatory action were reported in several animals' seizure models. To determine the effects of acute (single) and chronic (once daily for 7 consecutive days) administration of lovastatin on the protective activity of four classical antiepileptic drugs such as carbamazepine, phenobarbital, phenytoin and valproate in the mouse maximal electroshock seizure model. Seizure activity (maximal electroconvulsions) in mice were generated by alternating current delivered via ear-clip electrodes. Adverse-effect profile of lovastatin combinations with the tested antiepileptic drugs was assessed in the chimney test (motor performance). Total brain concentrations of antiepileptic drugs were evaluated with the fluorescence polarization immunoassay technique as a measure of the pharmacokinetic interaction between drugs. Lovastatin administered acutely or chronically (5-20 mg/kg) did not significantly affect the threshold for electroconvulsions in mice. Acute lovastatin (10 mg/kg) significantly enhanced the anticonvulsant effect of valproate, which was accompanied with a 34% significant increase in total brain concentration of valproate. Acute lovastatin in combination with phenytoin impaired motor performance by notably decreasing the TD₅₀ value of phenytoin. Chronic lovastatin (10 mg/kg) markedly enhanced the anticonvulsant potential of phenytoin. Acute lovastatin increased anticonvulsant action of valproate but also significantly raised level of valproate in brain after combined administration suggesting pharmacokinetic nature of interaction. The combinations of chronic lovastatin combined with phenytoin can potentially enhance the anticonvulsant potency of phenytoin.

Disturbances of brain cholesterol metabolism: A new excitotoxic process associated with status epilepticus

The understanding of the excitotoxic processes associated with a severe status epilepticus (SE) is of major importance. Changes of brain cholesterol homeostasis is an emerging candidate for excitotoxicity. We conducted an overall analysis of the cholesterol homeostasis both (i) in fluids and tissues from patients with SE: blood (n = 63, n = 87 controls), CSF (n = 32, n = 60 controls), and post-mortem brain tissues (n = 8, n = 8 controls) and (ii) in a mouse model of SE induced by an intrahippocampal injection of kainic acid. 24-hydroxycholesterol levels were decreased in kainic acid mouse hippocampus and in human plasma and post-mortem brain tissues of patients with SE when compared with controls. The decrease of 24-hydroxycholesterol levels was followed by increased cholesterol levels and by an increase of the cholesterol synthesis. Desmosterol levels were higher in human CSF and in mice and human hippocampus after SE. Lanosterol and dihydrolanosterol levels were higher in plasma from SE patients. Our results suggest that a CYP46A1 inhibition could occur after SE and is followed by a brain cholesterol accumulation. The excess of cholesterol is known to be excitotoxic for neuronal cells and may participate to neurological sequelae observed after SE. This study highlights a new pathophysiological pathway involved in SE excitotoxicity.

Gene Expression Analysis Identifies Cholesterol Metabolism Dysregulation in Hippocampus of Phenytoin-Resistant Pentylenetetrazol-Kindled Epileptic Mice

Pharmaco-resistant Epilepsy has been a major challenge for medical interventions in controlling seizures. To date, up to 33% of the patients with epilepsy do not show adequate response to anti-epileptic drugs even after prolonged combinatorial drug usage. Using microarray, this study explores the changes in hippocampal gene expression in the phenytoin-resistant pentylenetetrazol (PTZ)-kindled mouse model of epilepsy. Our results from mRNA microarray analysis show distinct gene expression profiles in the hippocampus of phenytoin-resistant and sensitive mice. Pathway enrichment analysis showed differential expression of genes involved in cholesterol biosynthesis in phenytoin-resistant and sensitive mice.

Associations between statin use and suicidality, depression, anxiety, and seizures: a Swedish total-population cohort study

BACKGROUND

Statins have shown both protective and adverse associations with neuropsychiatric outcomes. We aimed to examine the possible associations between statins and suicidality, depression, anxiety, and seizures.

METHODS

Using Swedish national registers, we linked data on dispensed statin prescriptions with data on unplanned (emergency) hospital visits or specialised outpatient care for four neuropsychiatric outcomes: suicidal behaviour (including deaths from suicide), depressive disorders, anxiety disorders, and seizures. We included all individuals in the registries who were dispensed statins and who were aged 15 years or older between Jan 1, 2006, and Dec 31, 2013. We applied a within-individual design using stratified Cox proportional hazards regression to compare the incidence of the defined outcomes during periods on statins and periods off statins within each individual, thus adjusting for time-invariant confounders. Non-specific effects of treatment were tested by investigating these outcomes in relation to thiazide diuretic use and antihistamine use in the same cohort.

FINDINGS

The statin-users cohort comprised 1 149 384 individuals, of whom 1 015 949 (88·4%) were aged 50 years or older, 625 616 (54·4%) were male, and 523 768 (45·6%) were female. The study period consisted of 2 053 310 non-treatment periods and 2 997 545 treatment periods, and 957 216 (83·3%) individuals had a medication status change (from on statins to off statins, or vice versa). Suicide outcomes were found in 6372 (0·6%) individuals, depressive disorders in 23 745 (2·1%), anxiety disorders in 30 100 (2·6%), and seizures in 28 844 (2·5%). There were no clear associations between periods of statin treatment and suicidal behaviour or deaths from suicide (hazard ratio 0·99 [95% CI 0·90-1·08]), anxiety disorders (0·99 [0·95-1·02]), or seizures (1·00 [0·97-1·04]). Statins were associated with reduced hazards of depressive disorders (0·91 [0·87-0·94]), which remained after adjustment for concurrent antidepressant use (0·91 [0·88-0·94]). Hazard ratios for depressive disorders were 0·61 (0·38-1·00; n=14 718) with thiazide diuretic use and 0·84 (0·67-1·06; n=23 715) with antihistamine use.

INTERPRETATION

Statin use is not associated with suicidality, anxiety disorders, or seizures. Whether the observed association between statin use and reduced diagnoses of clinical depression is confounded by non-specific benefits related to being prescribed medication needs further research.

FUNDING

Wellcome Trust, Swedish Research Council, National Institute for Health Research (NIHR) Research Professorship, NIHR Oxford Health Biomedical Research Centre, American Foundation for Suicide Prevention, Karolinska Institutet.

Statin treatment can reduce incidence of early seizure in acute ischemic stroke: A propensity score analysis

A previous study showed early statin administration in patients with acute ischemic stroke (AIS) was associated with a lower risk of early-onset seizure (ES), which is a high risk of epilepsy, but this retrospective study design may not have eliminated confounding factor effects. We aimed to verify the determinants and prognostic significance of ES and clarify the effects of statin administration. Consecutive AIS patients without a history of epilepsy were enrolled. The relationship between ES (within 7 days of index-stroke) and statin treatment was assessed using multivariate and propensity scores (PS). Of 2,969 patients with AIS, 1,623 (54.6%) were treated with statin, and 66 (2.2%) developed ES. In logistic regression models, cortical stroke lesion [odds ratio (OR), 2.82; 95% confidence interval (CI), 1.29–7.28) and pre-morbid modified Rankin Scale (per 1 point) (OR, 1.39; 95% CI, 1.18–1.65) were higher risks for ES, while statin significantly reduced the risk of ES (OR, 0.44; 95% CI, 0.24–0.79). In accordance with PS-matching, statin treatment produced consistent results for ES after adjusting by inverse probability of treatment-weighting PS (OR, 0.41; 95% CI, 0.22–0.75). In conclusion, as previously, statin treatment was independently associated with a lower risk of ES in AIS.