Lower Serum Iron and Hemoglobin Levels are Associated with Acute Seizures in Patients with Ruptured Cerebral Aneurysms

Revealing the mechanisms of blood-brain barrier in chronic neurodegenerative disease: an opportunity for therapeutic intervention

The brain microenvironment is tightly regulated, and the blood-brain barrier (BBB) plays a pivotal role in maintaining the homeostasis of the central nervous system. It effectively safeguards brain tissue from harmful substances in peripheral blood. However, both acute pathological factors and age-related biodegradation have the potential to compromise the integrity of the BBB and are associated with chronic neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD), as well as Epilepsy (EP). This association arises due to infiltration of peripheral foreign bodies including microorganisms, immune-inflammatory mediators, and plasma proteins into the central nervous system when the BBB is compromised. Nevertheless, these partial and generalized understandings do not prompt a shift from passive to active treatment approaches. Therefore, it is imperative to acquire a comprehensive and in-depth understanding of the intricate molecular mechanisms underlying vascular disease alterations associated with the onset and progression of chronic neurodegenerative disorders, as well as the subsequent homeostatic changes triggered by BBB impairment. The present article aims to systematically summarize and review recent scientific work with a specific focus on elucidating the fundamental mechanisms underlying BBB damage in AD, PD, and EP as well as their consequential impact on disease progression. These findings not only offer guidance for optimizing the physiological function of the BBB, but also provide valuable insights for developing intervention strategies aimed at early restoration of BBB structural integrity, thereby laying a solid foundation for designing drug delivery strategies centered around the BBB.

Restless legs syndrome in patients with epilepsy: risk analysis, polysomnography, and quality of life evaluation

STUDY OBJECTIVES

Restless legs syndrome (RLS) is a circadian rhythm related sensorimotor disorder due to brain iron deficiency, with lesion sites at the putamen and substantia nigra. However, epilepsy is a disease with abnormal electric discharge from the cortex and can be triggered with iron disequilibrium. We designed a case-control study to discover the association between epilepsy and RLS.

METHODS

A total of 24 patients with epilepsy and RLS and 72 patients with epilepsy without RLS were included. Most of the patients underwent polysomnography and video electroencephalogram tests and took sleep questionnaires. We collected information on seizure characteristics, including general or focal onset, epileptogenic focus, current antiseizure medications, medically responsive epilepsy or refractory epilepsy, and nocturnal attacks. The sleep architectures of the two groups were compared. We analyzed the risk factors for RLS using multivariate logistic regression.

RESULTS

Among the patients with epilepsy, the occurrence of RLS was associated with refractory epilepsy (OR 6.422, p = 0.002) and nocturnal seizures (OR 4.960, p = 0.005). Sleep parameters were not significantly associated with RLS status. Quality of life was significantly impaired in the group with RLS in both the physical and mental domains.

CONCLUSIONS

Refractory epilepsy and nocturnal seizures were strongly correlated with RLS in patients with epilepsy. RLS should be considered a predictable comorbidity in patients with epilepsy. The management of RLS not only led to better control of the patient's epilepsy but also improved their quality of life.

The association between hematologic traits and aneurysm-related subarachnoid hemorrhage: a two-sample mendelian randomization study

Several hematologic traits have been suggested to potentially contribute to the formation and rupture of intracranial aneurysms (IA). The purpose of this study is to explore the causal association between hematologic traits and the risk of IA. To explore the causal association between hematologic traits and the risk of IA, we employed two-sample Mendelian randomization (MR) analysis. Two independent summary-level GWAS data were used for preliminary and replicated MR analyses. The inverse variance weighted (IVW) method was employed as the primary method in the MR analyses. The stabilities of the results were further confirmed by a meta-analysis. In the preliminary MR analysis, hematocrit, hemoglobin concentration (p = 0.0047), basophil count (p = 0.0219) had a suggestive inverse causal relationship with the risk of aneurysm-associated subarachnoid hemorrhage (aSAH). The monocyte percentage of white cells (p = 0.00956) was suggestively positively causally correlated with the risk of aSAH. In the replicated MR analysis, only the monocyte percentage of white cells (p = 0.00297) remained consistent with the MR results in the preliminary analysis. The hematocrit, hemoglobin concentration, and basophil count no longer showed significant causal relationship (p > 0.05). Meta-analysis results further confirmed that only the MR result of monocyte percentage of white cells reached significance in the random effect model and fixed effect model. None of the 25 hematologic traits was causally associated with the risk of unruptured intracranial aneurysms (uIA). This study revealed a suggestive positive association between the monocyte percentage of white cells and the risk of aSAH. This finding contributes to a better understanding that monocytes/macrophages could participate in the risk of aSAH.

Lower Serum Iron Level Predicts Postoperative Global Cerebral Edema Following Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Iron plays an important role in neuronal injury and edema formation after intracranial hemorrhage. However, the role of serum iron in aneurysmal subarachnoid hemorrhage (aSAH) is yet to be well-established. This study aims to identify whether serum iron could predict postoperative global cerebral edema (GCE) and poor outcome in aSAH.

METHODS

847 patients' aSAH clinical data were retrospectively collected at the First Affiliated Hospital of Fujian Medical University. Data on demographics, clinical characteristics, and laboratory values were collected and analyzed through univariate and multivariate analyses. Propensity score matching (PSM) analysis was performed to balance the baseline differences between the groups.

RESULTS

The incidence of high-grade global cerebral edema (H-GCE) following aSAH was 12.99% (110/847). Serum iron levels [odds ratio (OR) = 1.143; 95% confidence interval (CI), (1.097-1.191); p < 0.001] were associated with the occurrence of H-GCE following aSAH in the univariate analysis. This association remained statistically significant even after adjusting for other variables in the multivariate model, with serum iron having an OR of 1.091 (95% CI, 1.043-1.141; p < 0.001) for GCE. After 1:1 PSM, serum iron levels ≤ 10.7 µmol/L remained a significant independent predictor of GCE (p = 0.002). The receiver operating characteristic (ROC) curve analysis determined that a serum iron cut-off value of ≤ 10.7 µmol/L was optimal for predicting H-GCE [Areas under the ROC curves (AUC) = 0.701, 95% CI, (0.669-0.732), p < 0.001; sensitivity, 67.27%; specificity, 63.77%] in patients with aSAH. Additionally, a trend was observed in which higher Hunt-Hess grades (HH grade) were associated with lower serum iron levels, and higher modified Fisher grades (mFisher grade) were associated with lower serum iron levels. In addition, the serum iron level was also associated with a 3-month functional neurological outcome (p < 0.001).

CONCLUSIONS

The results of this study indicate that a decreased serum iron level serves as a clinically significant biomarker for the prediction of postoperative GCE and a poor outcome at 3-months in patients with aSAH.

Reevaluation of risk factors for aneurysmal subarachnoid hemorrhage associated epilepsy

BACKGROUND

Symptomatic epilepsy is a common complication of aneurysmal subarachnoid hemorrhage (aSAH) associated with poor outcome. We sought to analyze the risk factors leading to post-SAH epilepsy.

METHODS

All consecutive aSAH cases treated between 01/2003 and 06/2016 were retrospectively included. Post-aSAH period was followed up to 03/2020 for the occurrence of epilepsy. Demographic characteristics and previous medical history of the patients, parameters of initial severity, performed treatments, certain early and late complications of aSAH, as well as routine laboratory and vital parameter measurements were collected. Functional outcome was assessed at discharge and 6 months after aSAH using the modified Rankin scale (mRS).

RESULTS

During the post-aSAH follow-up (median: 8.93 months/patient), 85 of 948 individuals (9%) in the final analysis developed symptomatic epilepsy (median: 3.43 months). In the majority of cases, epilepsy was diagnosed >3 weeks after aSAH (n = 67, 78.8%) and in survivors with poor outcome at discharge (mRS = 4-5, 15.8% vs. 5.3%, p < 0.0001). Of over 150 analyzed potential risk factors, the following parameters were independently associated with the risk of symptomatic epilepsy after aSAH: thyroid dysfunction (aHR = 1.81, p = 0.029), need for decompressive craniectomy (aHR = 2.32, p = 0.011) and shunt placement (aHR = 1.94, p = 0.022), prolonged tachycardia (≥4 days, aHR = 2.06, p = 0.025), as well as anemia signs (mean red blood cell count <3.6 × 10¹² /L [aHR = 2.4, p = 0.015] and mean hematocrit <31% [aHR = 2.13, p = 0.044]) during first 2 weeks after aSAH.

CONCLUSION

Symptomatic epilepsy occurs predominantly in individuals with poor outcome at discharge and after the acute phase of aSAH. Knowledge of risk factors associated with aSAH-related epilepsy might help in early identification and treatment of compromised individuals, and therefore, help to improve their outcome.

Modifiable risk factors for intracranial aneurysms: Evidence from genetic studies

Background:

Intracranial aneurysm (IA) is a crucial health concern with limited strategies for prevention and treatment.

Aim:

To identify potentially modifiable risk factors, such as socioeconomic, behaviors, dietary, and cardiometabolic factors, for IA and its subtypes.

Methods:

Summary statistics for IA were derived from a genome-wide association study with an overall 79,429 participants. Single nucleotide polymorphisms associated with modifiable risk factors at genome-wide significance ( P = 5 × 10–8) were used as instrumental variables. The inverse-variance-weighted method, weighted-median method, Mendelian randomization (MR)-Egger regression, MR-Pleiotropy RESidual Sum and Outlier, and multivariable MR analyses were performed to evaluate the effect estimates.

Results:

Genetically predicted educational attainment, insomnia, smoking, and systolic and diastolic blood pressure (SBP and DBP) were significantly associated with the risk of IA. The odds ratios (ORs) were 0.44 (95% confidence interval (CI): 0.37–0.52) for educational attainment, 1.15 (95% CI: 1.08–1.23) for insomnia, 1.56 (95% CI: 1.38–1.75) for smoking initiation, 2.69 (95% CI: 1.77–4.07) for cigarette per day, 2.65 (95% CI: 1.72–4.08) for lifetime smoking, 1.07 (95% CI: 1.06–1.09), and 1.06 (95% CI: 1.04–1.10) for SBP and DBP, respectively. Similar effect estimates were observed for unruptured IAs and aneurysmal subarachnoid hemorrhage.

Conclusions:

This study provided genetic evidence that several modifiable risk factors, including blood pressure, smoking, educational attainment, and insomnia were associated with the risk of IA.

Emerging Role of Microglia-Mediated Neuroinflammation in Epilepsy after Subarachnoid Hemorrhage

Epilepsy is a common and serious complication of subarachnoid hemorrhage (SAH), giving rise to increased morbidity and mortality. It's difficult to identify patients at high risk of epilepsy and the application of anti-epileptic drugs (AEDs) following SAH is a controversial topic. Therefore, it's pressingly needed to gain a better understanding of the risk factors, underlying mechanisms and the optimization of therapeutic strategies for epilepsy after SAH. Neuroinflammation, characterized by microglial activation and the release of inflammatory cytokines, has drawn growing attention due to its influence on patients with epilepsy after SAH. In this review, we discuss the risk factors for epilepsy after SAH and emphasize the critical role of microglia. Then we discuss how various molecules arising from pathophysiological changes after SAH activate specific receptors such as TLR4, NLRP3, RAGE, P2X7R and initiate the downstream inflammatory pathways. Additionally, we focus on the significant responses implicated in epilepsy including neuronal excitotoxicity, the disruption of blood-brain barrier (BBB) and the change of immune responses. As the application of AEDs for seizure prophylaxis after SAH remains controversial, the regulation of neuroinflammation targeting the key pathological molecules could be a promising therapeutic method. While neuroinflammation appears to contribute to epilepsy after SAH, more comprehensive experiments on their relationships are needed.