Intracranial heme metabolism and cerebral vasospasm after aneurysmal subarachnoid hemorrhage

Pharmacogenetic and clinical risk factors for bevacizumab-related gastrointestinal hemorrhage in prostate cancer patients treated on CALGB 90401 (Alliance)

The objective of this study was to discover clinical and pharmacogenetic factors associated with bevacizumab-related gastrointestinal hemorrhage in Cancer and Leukemia Group B (Alliance) 90401. Patients with metastatic castration-resistant prostate cancer received docetaxel and prednisone ± bevacizumab. Patients were genotyped using Illumina HumanHap610-Quad and assessed using cause-specific risk for association between single nucleotide polymorphisms (SNPs) and gastrointestinal hemorrhage. In 1008 patients, grade 2 or higher gastrointestinal hemorrhage occurred in 9.5% and 3.8% of bevacizumab (n = 503) and placebo (n = 505) treated patients, respectively. Bevacizumab (P < 0.001) and age (P = 0.002) were associated with gastrointestinal hemorrhage. In 616 genetically estimated Europeans (n = 314 bevacizumab and n = 302 placebo treated patients), grade 2 or higher gastrointestinal hemorrhage occurred in 9.6% and 2.0% of patients, respectively. One SNP (rs1478947; HR 6.26; 95% CI 3.19-12.28; P = 9.40 × 10-8) surpassed Bonferroni-corrected significance. Grade 2 or higher gastrointestinal hemorrhage rate was 33.3% and 6.2% in bevacizumab-treated patients with the AA/AG and GG genotypes, versus 2.9% and 1.9% in the placebo arm, respectively. Prospective validation of these findings and functional analyses are needed to better understand the genetic contribution to treatment-related gastrointestinal hemorrhage.

Roles of Bilirubin in Hemorrhagic Transformation of Different Types and Severity

BACKGROUND

Hemorrhagic transformation (HT) is a severe complication in patients with acute ischemic stroke (AIS). This study was performed to explore and validate the relation between bilirubin levels and spontaneous HT (sHT) and HT after mechanical thrombectomy (tHT).

METHODS

The study population consisted of 408 consecutive AIS patients with HT and age- and sex-matched patients without HT. All patients were divided into quartiles according to total bilirubin (TBIL) level. HT was classified as hemorrhagic infarction (HI) and parenchymal hematoma (PH) based on radiographic data.

RESULTS

In this study, the baseline TBIL levels were significantly higher in the HT than non-HT patients in both cohorts (p < 0.001). Furthermore, the severity of HT increased with increasing TBIL levels (p < 0.001) in sHT and tHT cohorts. The highest quartile of TBIL was associated with HT in sHT and tHT cohorts (sHT cohort: OR = 3.924 (2.051-7.505), p < 0.001; tHT cohort: OR = 3.557 (1.662-7.611), p = 0.006).

CONCLUSIONS

Our results suggest that an increased TBIL is associated with a high risk of patients with sHT and tHT, and that TBIL is more suitable as a predictor for sHT than tHT. These findings may help to identify patients susceptible to different types and severity of HT.

Continuous lumbar drainage after aneurysmal subarachnoid hemorrhage decreased malondialdehyde in cerebrospinal fluid and improved outcome

PURPOSE

The use of a continuous lumbar drain (LD) for the treatment of aneurysmal subarachnoid hemorrhage (aSAH), and malondialdehyde (MDA), a marker of oxidative stress, is correlated with clinical outcome. This study aimed to investigate the relationship between LD placement and MDA level after aSAH.

METHODS

Patients with modified Fisher's grade III and IV aSAH who underwent early aneurysm obliteration were enrolled. Cerebrospinal fluid (CSF) was obtained on day 7 after aSAH in non-LD group. In LD group, the LD was inserted on day 3 after aSAH for continuous CSF drainage. The levels of intrathecal hemoglobin, total bilirubin, ferritin, and MDA were measured.

RESULTS

There were 41 patients in non-LD group (age: 58.7 ± 13.7 years; female: 61.0%) and 48 patients in LD group (age: 58.3 ± 10.4 years; female: 79.2%). There were more favorable outcomes (Glasgow Outcome Scale ≥4) at 3 months after aSAH in LD group (p = 0.0042). The intrathecal hemoglobin, total bilirubin, ferritin, and MDA levels at day 7 after aSAH were all significantly lower in LD group. An older age (>60 years) (p = 0.0293), higher MDA level in the CSF (p = 0.0208), and delayed ischemic neurological deficit (p = 0.0451) were independent factors associated with unfavorable outcomes. LD placement was associated with a decreased intrathecal MDA level on day 7 after aSAH (p < 0.001).

CONCLUSION

The intrathecal MDA level at day 7 after aSAH can be an effective outcome indicator in modified Fisher's grade III/IV aSAH. Continuous CSF drainage via a LD can decrease the intrathecal MDA level and improve the functional outcome.

Elucidating the progress and impact of ferroptosis in hemorrhagic stroke

Hemorrhagic stroke is a devastating cerebrovascular disease with high morbidity and mortality, for which effective therapies are currently unavailable. Based on different bleeding sites, hemorrhagic stroke can be generally divided into intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH), whose pathogenesis share some similarity. Ferroptosis is a recently defined programmed cell deaths (PCDs), which is a critical supplement to the hypothesis on the mechanism of nervous system injury after hemorrhagic stroke. Ferroptosis is characterized by distinctive morphological changes of mitochondria and iron-dependent accumulation of lipid peroxides. Moreover, scientists have successfully demonstrated the involvement of ferroptosis in animal models of ICH and SAH, indicating that ferroptosis is a promising target for hemorrhagic stroke therapy. However, the studies on ferroptosis still faces a serious of technical and theoretical challenges. This review systematically elaborates the role of ferroptosis in the pathogenesis of hemorrhagic stroke and puts forward some opinions on the dilemma of ferroptosis research.

Inflammation and immune cell abnormalities in intracranial aneurysm subarachnoid hemorrhage (SAH): Relevant signaling pathways and therapeutic strategies

Intracranial aneurysm subarachnoid hemorrhage (SAH) is a cerebrovascular disorder associated with high overall mortality. Currently, the underlying mechanisms of pathological reaction after aneurysm rupture are still unclear, especially in the immune microenvironment, inflammation, and relevant signaling pathways. SAH-induced immune cell population alteration, immune inflammatory signaling pathway activation, and active substance generation are associated with pro-inflammatory cytokines, immunosuppression, and brain injury. Crosstalk between immune disorders and hyperactivation of inflammatory signals aggravated the devastating consequences of brain injury and cerebral vasospasm and increased the risk of infection. In this review, we discussed the role of inflammation and immune cell responses in the occurrence and development of aneurysm SAH, as well as the most relevant immune inflammatory signaling pathways [PI3K/Akt, extracellular signal-regulated kinase (ERK), hypoxia-inducible factor-1α (HIF-1α), STAT, SIRT, mammalian target of rapamycin (mTOR), NLRP3, TLR4/nuclear factor-κB (NF-κB), and Keap1/nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/ARE cascades] and biomarkers in aneurysm SAH. In addition, we also summarized potential therapeutic drugs targeting the aneurysm SAH immune inflammatory responses, such as nimodipine, dexmedetomidine (DEX), fingolimod, and genomic variation-related aneurysm prophylactic agent sunitinib. The intervention of immune inflammatory responses and immune microenvironment significantly reduces the secondary brain injury, thereby improving the prognosis of patients admitted to SAH. Future studies should focus on exploring potential immune inflammatory mechanisms and developing additional therapeutic strategies for precise aneurysm SAH immune inflammatory regulation and genomic variants associated with aneurysm formation.

The Role of Circadian Clock Genes in Critical Illness: The Potential Role of Translational Clock Gene Therapies for Targeting Inflammation, Mitochondrial Function, and Muscle Mass in Intensive Care

The Earth's 24-h planetary rotation, with predictable light and heat cycles, has driven profound evolutionary adaptation, with prominent impacts on physiological mechanisms important for surviving critical illness. Pathways of interest include inflammation, mitochondrial function, energy metabolism, hypoxic signaling, apoptosis, and defenses against reactive oxygen species. Regulation of these by the cellular circadian clock (BMAL-1 and its network) has an important influence on pulmonary inflammation; ventilator-associated lung injury; septic shock; brain injury, including vasospasm; and overall mortality in both animals and humans. Whether it is cytokines, the inflammasome, or mitochondrial biogenesis, circadian medicine represents exciting opportunities for translational therapy in intensive care, which is currently lacking. Circadian medicine also represents a link to metabolic determinants of outcome, such as diabetes and cardiovascular disease. More than ever, we are appreciating the problem of circadian desynchrony in intensive care. This review explores the rationale and evidence for the importance of the circadian clock in surviving critical illness.

Label-Free Cholesteric Liquid Crystal Biosensing Chips for Heme Oxygenase-1 Detection within Cerebrospinal Fluid as an Effective Outcome Indicator for Spontaneous Subarachnoid Hemorrhage

A novel device for cholesteric liquid crystal (LC; CLC)-based biosensing chips for detecting heme oxygenase (HO)-1 within the cerebrospinal fluid (CSF) was invented. In the CLC device, the reorientation of the LCs was strongly influenced by the alignment layer surface and adjacent LCs. When the substrate was coated with the alignment layer, the CLCs oriented homeotropically in a focal conic state. Once HO-1 was immobilized onto the orientation sheet-coated substrate, the CLC changed from a focal conic state to a bright planar state by disrupting the CLCs. The concentration of HO-1 within CSF was shown to be an effective outcome indicator for patients with a spontaneous subarachnoid hemorrhage. We showed that the CLC immunoassaying can be used to measure HO-1 with a lower detection limit of about 10 ng/mL. The linear range was 10 ng/mL to 1 mg/mL. An easy-to-use, rapid-detection, and label-free CLC immunoassay device is proposed.

Ruptured AComA aneurysm and asymptomatic bilateral ACA vasospasm in an infant: surgical case report

Intracranial aneurysms (IAs) are localized dilations of the cerebral vasculature, representing the leading cause for non-traumatic subarachnoid hemorrhage and an important source of morbidity and mortality. Despite it being a frequent pathology and most often diagnosed incidentally, IAs in infants are a very rare occurrence, and the ruptured variant is exceptional. A 4-month-old boy with a negative family history was brought to our department because of several episodes of incoercible vomiting and fever. Upon examination, the child was somnolent, without any noticeable deficit. Transfontanellar ultrasonography and CT angiography revealed a ruptured aneurysm of the anterior communicating artery (AComA), whereas the pre-clipping MRI showed thin, almost angiographically invisible anterior cerebral arteries (ACAs) on both sides due to vasospasm. We intervened surgically by placing an external ventricular shunt in an emergency setting, followed by clipping of the IA in a delayed manner. The child was discharged a month after admission with no deficit, despite the paradoxical aspect of the ACA. Ruptured IAs can be safely treated via microsurgery, even in infants. However, this requires a great amount of experience and surgical expertise. Furthermore, the lack of proper management would most likely result in a severe deficit in the long term. Lastly, the lack of visibility of the ACA on angiographic studies may not have neurological consequences if they occur in this age group.

Iron homeostasis pathway DNA methylation trajectories reveal a role for STEAP3 metalloreductase in patient outcomes after aneurysmal subarachnoid hemorrhage

BACKGROUND

Following aneurysmal subarachnoid hemorrhage (aSAH), the brain is susceptible to ferroptosis, a type of iron-dependent cell death. Therapeutic intervention targeting the iron homeostasis pathway shows promise for mitigating ferroptosis and improving recovery in animal models, but little work has been conducted in humans. DNA methylation (DNAm) plays a key role in gene expression and brain function, plasticity, and injury recovery, making it a potentially useful biomarker of outcomes or therapeutic target for intervention. Therefore, in this longitudinal, observational study, we examined the relationships between trajectories of DNAm in candidate genes related to iron homeostasis and acute (cerebral vasospasm and delayed cerebral ischemia) and long-term (Glasgow Outcome Scale [GOS, unfavorable = 1-3] and death) patient outcomes after aSAH.

RESULTS

Longitudinal, genome-wide DNAm data were generated from DNA extracted from post-aSAH cerebrospinal fluid (n = 260 participants). DNAm trajectories of 637 CpG sites in 36 candidate genes related to iron homeostasis were characterized over 13 days post-aSAH using group-based trajectory analysis, an unsupervised clustering method. Significant associations were identified between inferred DNAm trajectory groups at several CpG sites and acute and long-term outcomes. Among our results, cg25713625 in the STEAP3 metalloreductase gene (STEAP3) stood out. Specifically, in comparing the highest cg25713625 DNAm trajectory group with the lowest, we observed significant associations (i.e., based on p-values less than an empirical significance threshold) with unfavorable GOS at 3 and 12 months (OR = 11.7, p = 0.0006 and OR = 15.6, p = 0.0018, respectively) and death at 3 and 12 months (OR = 19.1, p = 0.0093 and OR = 12.8, p = 0.0041, respectively). These results were replicated in an independent sample (n = 100 participants) observing significant associations with GOS at 3 and 12 months (OR = 8.2, p = 0.001 and OR = 6.3, p = 0.0.0047, respectively) and death at 3 months (OR = 2.3, p = 0.008) and a suggestive association (i.e., p-value < 0.05 not meeting an empirical significance threshold) with death at 12 months (OR = 2.0, p = 0.0272). In both samples, an additive effect of the DNAm trajectory group was observed as the percentage of participants with unfavorable long-term outcomes increased substantially with higher DNAm trajectory groups.

CONCLUSION

Our results support a role for DNAm of cg25713625/STEAP3 in recovery following aSAH. Additional research is needed to further explore the role of DNAm of cg25713625/STEAP3 as a biomarker of unfavorable outcomes, or therapeutic target to improve outcomes, to translate these findings clinically.

Cerebrospinal Fluid from Aneurysmal Subarachnoid Hemorrhage Patients Leads to Hydrocephalus in Nude Mice

OBJECTIVE

Our prior studies have found that intracerebroventricular injection of blood components can cause hydrocephalus and choroid plexus epiplexus cell activation in rats. To minimize the cross-species reaction, the current study examines whether intraventricular injection of acellular components of cerebrospinal fluid (CSF) from subarachnoid hemorrhage patients can cause hydrocephalus and epiplexus macrophage activation in nude mice which lack a T cell inflammatory response.

METHODS

Adult male nude mice received intraventricular injections of acellular CSF from subarachnoid hemorrhage patients or a control patient. All mice had preoperative magnetic resonance imaging as baseline and postoperative scans at 24 h after CSF injection to determine ventricular volume. Brains were harvested at 24 h for brain histology, immunohistochemistry, and electron microscopy.

RESULTS

Intraventricular injection of CSF from two of five subarachnoid hemorrhage patients obtained < 48 h from ictus resulted in ventricular enlargement at 24 h. CSF-related hydrocephalus was associated with activation of epiplexus macrophages and ependymal injury.

CONCLUSIONS

Components of the acellular CSF of subarachnoid hemorrhage patients can cause epiplexus macrophage activation, ependymal cell damage, and ventricular enlargement in nude mice. This may serve as a unique model to study mechanisms of hydrocephalus development following subarachnoid hemorrhage.

Subarachnoid Hemorrhage Increases Level of Heme Oxygenase-1 and Biliverdin Reductase in the Choroid Plexus

Subarachnoid hemorrhage is a specific, life-threatening form of hemorrhagic stroke linked to high morbidity and mortality. It has been found that the choroid plexus of the brain ventricles forming the blood-cerebrospinal fluid barrier plays an important role in subarachnoid hemorrhage pathophysiology. Heme oxygenase-1 and biliverdin reductase are two of the key enzymes of the hemoglobin degradation cascade. Therefore, the aim of present study was to investigate changes in protein levels of heme oxygenase-1 and biliverdin reductase in the rat choroid plexus after experimental subarachnoid hemorrhage induced by injection of non-heparinized autologous blood to the cisterna magna. Artificial cerebrospinal fluid of the same volume as autologous blood was injected to mimic increased intracranial pressure in control rats. Immunohistochemical and Western blot analyses were used to monitor changes in the of heme oxygenase-1 and biliverdin reductase levels in the rat choroid plexus after induction of subarachnoid hemorrhage or artificial cerebrospinal fluid application for 1, 3, and 7 days. We found increased levels of heme oxygenase-1 and biliverdin reductase protein in the choroid plexus over the entire period following subarachnoid hemorrhage induction. The level of heme oxygenase-1 was the highest early (1 and 3 days) after subarachnoid hemorrhage indicating its importance in hemoglobin degradation. Increased levels of heme oxygenase-1 were also observed in the choroid plexus epithelial cells at all time points after application of artificial cerebrospinal fluid. Biliverdin reductase protein was detected mainly in the choroid plexus epithelial cells, with levels gradually increasing during subarachnoid hemorrhage. Our results suggest that heme oxygenase-1 and biliverdin reductase are involved not only in hemoglobin degradation but probably also in protecting choroid plexus epithelial cells and the blood-cerebrospinal fluid barrier from the negative effects of subarachnoid hemorrhage.

Serum bilirubin level correlates with mortality in patients with traumatic brain injury

As a catabolic product of hemoglobin, bilirubin has been confirmed playing an important role in the development of various central nervous system disease. The aim of this study is to explore the correlation between serum bilirubin level and mortality in patients with traumatic brain injury (TBI).Patients admitted with traumatic brain injury (TBI) in our hospital between January 2015 and January 2018 were enrolled in this study. Clinical and laboratory data of 361 patients were retrospectively collected to explore the independent risk factors of mortality.The comparison of baseline characteristics showed that non-survivors had lower Glasgow Coma Scale (GCS) (P < .001) and higher level of serum total bilirubin (TBIL) (P < .001) and direct bilirubin (DBIL) (P < .001). We found that only GCS (P < .001), glucose (P < .001), lactate dehydrogenase (LDH) (P = .042) and DBIL (P = .005) were significant risk factors in multivariate logistic regression analysis. GCS and DBIL had comparable AUC value (0.778 vs 0.750, P > .05) on predicting mortality in TBI patients. The AUC value of the combination of GCS and DBIL is higher than the single value of these two factors (P < .05). Moreover, predictive model 1 consisted of GCS, glucose, LDH and DBIL had the highest AUC value of 0.894.DBIL is a significant risk factor of mortality in TBI patients. Assessing the level of DBIL is beneficial for physicians to evaluate severity and predict outcome for TBI patients.

Attenuation of White Matter Damage Following Deferoxamine Treatment in Rats After Spinal Cord Injury

BACKGROUND

With little information available on axonal and myelin damage surrounding the contusion, the study of spinal cord injury (SCI) so far has focused on neuronal death. In this study, we investigated the role of iron overload in long-term oligodendroglia death and progressive white matter damage to rats after SCI using the iron chelator, deferoxamine (DFX).

METHODS

Female Sprague-Dawley rats received either a contusion at T10 or sham-surgery. The rats were treated with DFX or vehicle. All rats were evaluated in behavioral assessments and then euthanized at different time points. Spinal cords were analyzed by diaminobenzidine-enhanced Perls' staining, non-heme iron measurements, Western blotting, immunohistochemistry, and transmission electron microscopy.

RESULTS

Iron accumulation after SCI resulted in the upregulation of transferrin receptor and divalent metal transporter 1, which exacerbated the intracellular iron overload. DFX treatment reduced iron overload-induced delayed oligodendrocyte death (e.g., 21 days: 47.12 ± 10.5 vs. 20.02 ± 9.4 x 10³/mm² in the vehicle-treated group, n = 4, P < 0.05). After SCI, the markers of axonal damage and demyelination were increased in white matter in the vehicle-treated group compared with the DFX-treated group (P < 0.05).

CONCLUSIONS

Iron overload plays an important role in progressive white matter damage after SCI. DFX may be an effective treatment for white matter damage after SCI.

The role of haptoglobin and hemopexin in the prevention of delayed cerebral ischaemia after aneurysmal subarachnoid haemorrhage: a review of current literature

Delayed cerebral ischaemia (DCI) after aneurysmal subarachnoid haemorrhage (aSAH) is a major cause of mortality and morbidity. The pathophysiology of DCI after aSAH is thought to involve toxic mediators released from lysis of red blood cells within the subarachnoid space, including free haemoglobin and haem. Haptoglobin and hemopexin are endogenously produced acute phase proteins that are involved in the clearance of these toxic mediators. The aim of this review is to investigate the pathophysiological mechanisms involved in DCI and the role of both endogenous as well as exogenously administered haptoglobin and hemopexin in the prevention of DCI.

Haemoglobin scavenging in intracranial bleeding: biology and clinical implications

Haemoglobin is released into the CNS during the breakdown of red blood cells after intracranial bleeding. Extracellular free haemoglobin is directly neurotoxic. Haemoglobin scavenging mechanisms clear haemoglobin and reduce toxicity; these mechanisms include erythrophagocytosis, haptoglobin binding of haemoglobin, haemopexin binding of haem and haem oxygenase breakdown of haem. However, the capacity of these mechanisms is limited in the CNS, and they easily become overwhelmed. Targeting of haemoglobin toxicity and scavenging is, therefore, a rational therapeutic strategy. In this Review, we summarize the neurotoxic mechanisms of extracellular haemoglobin and the peculiarities of haemoglobin scavenging pathways in the brain. Evidence for a role of haemoglobin toxicity in neurological disorders is discussed, with a focus on subarachnoid haemorrhage and intracerebral haemorrhage, and emerging treatment strategies based on the molecular pathways involved are considered. By focusing on a fundamental biological commonality between diverse neurological conditions, we aim to encourage the application of knowledge of haemoglobin toxicity and scavenging across various conditions. We also hope that the principles highlighted will stimulate research to explore the potential of the pathways discussed. Finally, we present a consensus opinion on the research priorities that will help to bring about clinical benefits.

Lower Iron Levels Predict Acute Hydrocephalus Following Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE

We tested the hypothesis that low serum iron levels are associated with acute hydrocephalus following aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

Patients presenting with ruptured intracranial aneurysms were enrolled in the prospective observational study. Age, sex, history of diabetes, hypertension and hyperlipidemia, symptom onset, Fisher grade, Hunt-Hess grade, aneurysm location, hemoglobin, and serum iron were collected. Acute hydrocephalus was determined within 72 hours after subarachnoid hemorrhage. A propensity-score matching analysis was performed to correct imbalances in patient characteristics between hydrocephalus and non-hydrocephalus groups.

RESULTS

A total of 535 patients were included. Incidence of acute hydrocephalus was 20.0%. In multivariate logistic regression analysis, lower serum iron was considered as a risk factor of acute hydrocephalus, as well as delayed ischemic neurologic deficit and lower hemoglobin (P = 0.000). After propensity-score matching, lower serum iron was considered as an independent risk factor for acute hydrocephalus, whereas hemoglobin and delayed ischemic neurologic deficit were not. The matched hydrocephalus group had lower serum iron comparing with the matched non-hydrocephalus group (10.26 ± 5.33 mmol/L vs. 13.44 ± 5.18 mmol/L; P = 0.000). The optimal cut-off value for serum iron levels as a predictor for acute hydrocephalus in patients with aSAH was determined as 13.1 mmol/L in the receiver operating characteristic curve. Furthermore, lower serum iron levels (odds ratio 0.305; 95% confidence interval, 0.178-0.524; P = 0.000) and acute hydrocephalus (odds ratio 0.372; 95% confidence interval, 0.202-0.684; P = 0.001) were predictors of poor outcome, as well as higher Hunt-Hess grade and Fisher grade.

CONCLUSIONS

Lower serum iron levels after aSAH was a predictor of acute hydrocephalus and unfavorable outcome.

Utility of cerebrospinal fluid lactate in aneurysmal subarachnoid hemorrhage

Background:

An external ventricular drain (EVD) treats hydrocephalus in patients with aneurysmal subarachnoid hemorrhage (aSAH). This study examines the utility of cerebrospinal fluid (CSF) lactate collected from an EVD as a proposed biomarker to predict patient outcome and vasospasm/delayed cerebral ischemia.

Methods:

Consecutive adults admitted to Wake Forest Baptist Medical Center from 2010 to 2015 with aSAH were identified through the electronic medical record, and clinical variables were collected and analyzed for correlation with incidence of vasospasm and discharge outcome.

Results:

In all, 51 patients with aSAH and an EVD had CSF lactate measured which ranged from 1.9 to 6.2 mmol/L, with a median value of 3.2 mmol/L. Vasospasm based on transcranial Doppler assessment occurred in 29 patients (57%), of which 20 (45%) were clinically symptomatic. Good outcome (discharge to home/acute rehab) occurred in 35 patients (69%). Sixteen patients (31%) had an unfavorable outcome (died/discharged to nursing homes/long-term acute care facility). In multivariate regression analysis, unfavorable outcome at discharge (P = 0.02), elevated CSF protein (P = 0.04), and admission Hunt and Hess score 3–5 (P = 0.05) were significantly associated with higher CSF lactate. The risk of symptomatic vasospasm increased with lactate in univariate analysis, but did not reach statistical significance (P = 0.077).

Conclusion:

The measurement of the CSF biochemical markers using an EVD is feasible and safe. We found that elevated CSF lactate correlates with patient outcome. Larger prospective studies are needed to test the validity of this finding and for understanding the underlying pathophysiologic mechanisms.

Vascular diseases and bleedings

Diseases of the central nervous system that are caused by an underlying vascular pathology typically result in either hemorrhage or ischemia. Most prominent entities include spontaneous subarachnoid hemorrhage, spontaneous intracerebral hemorrhage, and ischemic stroke. For anatomic reasons, cerebrospinal fluid (CSF) qualifies as body fluid for the exploration of biomarkers in these disorders. Even though in subarachnoid hemorrhage a few CSF parameters have been established for routine diagnostic purposes, there is still an unmet need and broad interest in the identification of molecules that would allow further insight into disease mechanisms and supplement patients' medical care. This chapter provides an overview on what is presently known about CSF biomarkers in spontaneous subarachnoid hemorrhage, spontaneous intracerebral hemorrhage, and ischemic stroke. We recapitulate current evidence on established diagnostic tests, discuss the role of various CSF molecules in the pathophysiology of these diseases, and illuminate their potential use in future clinical practice. Furthermore, we address methodologic aspects as well as shortcomings of research in this field.

The evidence for a role of vasospasm in the pathogenesis of cerebral malaria

Due to delay in treatment, cerebral malaria (CM) remains a significant complication of Plasmodium falciparum infection and is a common cause of death from malaria. In addition, more than 10 % of children surviving CM have neurological and long-term cognitive deficits. Understanding the pathogenesis of CM enables design of supportive treatment, reducing neurological morbidity and mortality. Vaso-occlusion and brain swelling appear to be leading to clinical features, neuronal damage and death in CM. It is proposed that parasitized red blood cells (pRBC), due to cytoadhesion to the endothelium and vasospasm induced by reduced bioavailability of nitric oxide, are causes. Stasis of blood flow and accumulation of pRBC may allow, after schizont rupture, for high concentration of products of haemolysis to accumulate, which leads to localized nitric oxide depletion, inducing adhesion molecules and cerebral vasospasm. Features consistent with an involvement of vasospasm are rapid reversibility of neurological symptoms, intermittently increased or absent flow in medium cerebral artery detectable on Doppler ultrasound and hemispheric reversible changes on cerebral magnetic resonance imaging in some patients. Clinical trials of treatment that can rapidly reduce cerebral vasospasm, including nitric oxide donors, inhaled nitric oxide, endothelin or calcium antagonists, or tissue plasminogen activators, are warranted.

Cerebral vasospasm and corticospinal tract injury induced by a modified rat model of subarachnoid hemorrhage

OBJECTIVE

Double-hemorrhage rat models of subarachnoid hemorrhages (SAH) are most effective at simulating delayed cerebral vasospasms (CVS). The present study modified the models to minimize additional trauma and investigated injury of the corticospinal tract (CST) using diffusion tensor imaging (DTI).

METHODS

On the first day, 0.3ml of autologous arterial blood was collected by puncturing the caudal artery and injected into the cisterna magna via percutaneous puncture; and the operation was repeated on the third day. The diameters of the basilar artery (BA), middle cerebral artery (MCA), and anterior cerebral artery (ACA) were measured by magnetic resonance angiography on days 3, 5, 7, 9, and 11 post-SAH. Meanwhile, on days 3, 7, 11, 15 and 19, DTI was performed to evaluate the injury of the CST at cerebral peduncle (CP) and pyramidal tract (Py) by measuring fractional anisotropy (FA) value.

RESULTS

Blood was deposited mainly in the basal cistern. Diameters of BA, MCA, and ACA were significantly reduced. FA value of the CP was lower in the SAH group than in the control group; but FA value of Py wasn't different between the two groups.

CONCLUSION

This is a minimally-invasive and high performance rat model of SAH. Additionally, the occurrence of CVS is firm and the axons in CP are injured.

Brain iron metabolism and brain injury following subarachnoid hemorrhage: iCeFISH-pilot (CSF iron in SAH)

INTRODUCTION

Iron-mediated oxidative damage has been implicated in the genesis of cerebral vasospasm in animal models of SAH. We sought to explore the relationship between levels of non-protein bound iron in cerebrospinal fluid and the development of brain injury in patients with aneurysmal SAH.

METHODS

Patients admitted with aneurysmal subarachnoid hemorrhage to a Neurointensive care unit of an academic, tertiary medical center, with Hunt and Hess grades 2-4 requiring ventriculostomy insertion as part of their clinical management were included in this pilot study. Samples of cerebrospinal fluid (CSF) were obtained on days 1, 3, and 5. A fluorometric assay that relies on an oxidation sensitive probe was used to measure unbound iron, and levels of iron-handling proteins were measured by means of enzyme-linked immunosorbent assays. We prospectively collected and recorded demographic, clinical, and radiological data.

RESULTS

A total of 12 patients were included in this analysis. Median Hunt and Hess score on admission was 3.5 (IQR: 1) and median modified Fisher scale score was 4 (IQR: 1). Seven of 12 patients (58 %) developed delayed cerebral ischemia (DCI). Day 5 non-transferrin bound iron (NTBI) (7.88 ± 1 vs. 3.58 ± 0.8, p = 0.02) and mean NTBI (7.39 ± 0.4 vs. 3.34 + 0.4 p = 0.03) were significantly higher in patients who developed DCI. Mean redox-active iron, as well as day 3 levels of redox-active iron correlated with development of angiographic vasospasm in logistic regression analysis (p = 0.02); while mean redox-active iron and lower levels of ceruloplasmin on days 3, 5, and peak concentration were correlated with development of deep cerebral infarcts.

CONCLUSIONS

Our preliminary data indicate a causal relationship between unbound iron and brain injury following SAH and suggest a possible protective role for ceruloplasmin in this setting, particularly in the prevention of cerebral ischemia. Further studies are needed to validate these findings and to probe their clinical significance.

Prognostic value of intrathecal heme oxygenase–1 concentration in patients with Fisher Grade III aneurysmal subarachnoid hemorrhage

Object

Experimental studies have demonstrated the crucial role of posthemorrhagic erythrocyte catabolism in the pathogenesis of subarachnoid hemorrhage (SAH). The authors of this study aimed to investigate the prognostic value of a series of CSF biomarkers linked to heme metabolism in SAH patients.

Methods

Patients with Fisher Grade III aneurysmal SAH undergoing early aneurysm obliteration were enrolled. The levels of heme oxygenase–1 (HO-1), oxyhemoglobin, ferritin, and bilirubin in intrathecal CSF were measured on the 7th day posthemorrhage. The associations of functional outcome with clinical and CSF parameters were analyzed.

Results

The study included 41 patients (mean age 59 ± 14 years; 16 male, 25 female), 17 (41.5%) of whom had an unfavorable outcome (Glasgow Outcome Scale score ≤ 3) 3 months after SAH. In terms of the clinical data, age > 60 years, admission World Federation of Neurosurgical Societies Grade ≥ III, and the presence of acute hydrocephalus were independent factors associated with an unfavorable outcome. After adjusting for clinical parameters, a higher level of HO-1 appeared to be the most significant CSF parameter related to an unfavorable outcome among all tested CSF molecules (OR 0.934, 95% CI 0.883–0.989, p = 0.018). Further analysis using a generalized additive model identified a cutoff HO-1 value of 81.2 μM, with higher values predicting unfavorable outcome (82.4% accuracy).

Conclusions

The authors propose that the level of intrathecal CSF HO-1 at Day 7 post-SAH can be an effective outcome indicator in patients with Fisher Grade III aneurysmal SAH.

Deferoxamine attenuates acute hydrocephalus after traumatic brain injury in rats

Acute post-traumatic ventricular dilation and hydrocephalus are relatively frequent consequences of traumatic brain injury (TBI). Several recent studies have indicated that high iron levels in brain may relate to hydrocephalus development after intracranial hemorrhage. However, the role of iron in the development of post-traumatic hydrocephalus is still unclear. This study was to determine whether or not iron has a role in hydrocephalus development after TBI. TBI was induced by lateral fluid-percussion in male Sprague-Dawley rats. Some rats had intraventricular injection of iron. Acute hydrocephalus was measured by magnetic resonance T2-weighted imaging and brain hemorrhage was determined by T2* gradient-echo sequence imaging and brain hemoglobin levels. The effect of deferoxamine on TBI-induced hydrocephalus was examined. TBI resulted in acute hydrocephalus at 24 h (lateral ventricle volume: 24.1 ± 3.0 vs. 9.9 ± 0.2 mm(3) in sham group). Intraventricular injection of iron also caused hydrocephalus (25.7 ± 3.4 vs. 9.0 ± 0.6 mm(3) in saline group). Deferoxamine treatment attenuated TBI-induced hydrocephalus and heme oxygenase-1 upregulation. In conclusion, iron may contribute to acute hydrocephalus after TBI.

Estradiol reduces ferrous citrate complex-induced NOS2 up-regulation in cerebral endothelial cells by interfering the nuclear factor kappa B transactivation through an estrogen receptor β-mediated pathway

Hemorrhagic stroke caused leakage of red blood cells which converts to hemoglobin, heme, and iron accumulated at the lesions. High concentration of ferrous iron from subarachnoid hemorrhage (SAH) induced cerebral vasospasm. Using the two-hemorrhage SAH model in rats, we previously demonstrated that estradiol (E2) significantly attenuated the SAH-induced vasospasm by inhibiting the NOS2 expression. Adding ferrous citrate (FC) complexes to the primary cultured mouse cerebral endothelial cells (CEC) to mimic the SAH conditions, we also showed that FC up-regulates NOS2 through nuclear translocation of NFκB induced by free radicals generation. Here, we further studied the molecular mechanism underlying E2-mediated reduction of the FC-induced up-regulation of NOS2. Treatment with E2 (100 nM) reduced the FC (100 µM)-induced increases of free radical generation and the levels of NOS2 mRNA and protein in the CEC. Moreover, E2 also prevented the FC-induced increases of IκBα phosphorylation, NFκB nuclear translocation, NFκB binding onto the NOS2 promoter, and the NOS2 promoter luciferase activity. However, knock-down the estrogen receptor β (ERβ), but not ERα, abolished the E2-mediated prevention on the FC-induced increases of NOS2 mRNA and protein. The data from the present study suggest that E2 inhibited NOS2 gene expression by interfering with NFκB nuclear translocation and NFκB binding onto the NOS2 through an ERβ-mediated pathway. Our results provide the molecular basis for designing the applicable therapeutic or preventive strategies in the treatment SAH patients.

Effects of topical administration of nimodipine on cerebral blood flow following subarachnoid hemorrhage in pigs

We sought to explore whether topical administration of nimodipine improves the abnormal cerebral perfusion following subarachnoid hemorrhage (SAH) in pigs. Fourteen pigs were randomly divided into three groups: sham (n=4), SAH (n=5), or SAH + nimodipine (n=5). The SAH model was established by injecting fresh autologous nonheparinized arterial blood into the suprasellae cistern. Nimodipine or saline placebo (0.04 g/mL) were administered to the operative area on the fourth day after the SAH model was established. The cerebral blood flow (CBF) was measured 60 min after topical administration of nimodipine by cranial SPECT/CT scans with 5 mCi 99mTc-ECD injected intravenously. The CCR (corticocebellar ratio) was calculated by dividing the counts/voxel of the whole cerebral hemisphere by the average count/voxel in the cerebellar region of reference and RD (relative dispersion). A predictor for impaired autoregulation of CBF was calculated by dividing standard deviation (SD) of regional perfusion by mean perfusion (RD=SD/Mean). CCR and RD were applied to describe hemisphere CBF and perfusion heterogeneity. Cerebral perfusion significantly decreased in the SAH group (CCR: 1.382±0.192, RD: 0.417±0.015) compared to sham (CCR: 1.988±0.346, RD 0.389±0.015) (p<0.05). Abnormal cerebral perfusion status, however, was not significantly improved in the nimodipine + SAH group (CCR: 1.503±0.107, RD: 0.425±0.018) compared to the SAH group (p>0.05). Topical administration of nimodipine did not significantly improve CBF following SAH. These findings were not consistent with our previous data demonstrating that the topical administration of nimodipine significantly alleviates cerebral vasospasm following SAH detected by TCD. Potential mechanisms governing these disparate outcomes require further investigation.

Vasospasm after aneurysmal subarachnoid hemorrhage: recent advances in endovascular management

PURPOSE OF REVIEW

In a rapidly advancing specialty, it is essential to review the recent studies of alternative new treatments and present their efficacy, safety and outcome. We discuss the recent advances in the endovascular treatment of cerebral vasospasm following aneurysmal subarachnoid hemorrhage in the past few years with special focus on the literature regarding this subject in the last 18-24 months.

RECENT FINDINGS

The recent findings are as follows: effect of papaverine on brain oxygen; recent evaluation concerning nimodipine use; combined intraarterial and intravenous use of milrinone; illustration of the numerous recent studies on nicardipine; the safety and efficacy of high-dose intraarterial verapamil; outcome and adverse effects of intraarterial fasudil; transluminal balloon angioplasty; and recent evaluation of its efficacy and evaluation of its prophylactic use.

SUMMARY

Endovascular treatment, including intraarterial vasodilators and transluminal balloon angioplasty, has a very important place in the management of symptomatic vasospasm related to aneurysmal subarachnoid hemorrhage. The efficacy of intraarterial vasodilators has been proven. Numerous studies and analysis of different treatments of cerebrovascular vasospasm took place in the past period. This allowed more understanding and evaluation of their outcome, safety and efficacy helping physicians to choose better treatments to adopt. It emphasizes also the aspects that need more study and research.

Neuronavigation-assisted single transseptal catheter implantation and shunt in patients with posthemorrhagic hydrocephalus and accentuated lateral ventricles dilatation

Background:

To assess the treatment of posthemorrhagic hydrocephalus with accentuated lateral ventricles dilatation by employing a single biventricular neuronavigation-assisted transseptal-implanted catheter with programmable valve and distal peritoneal derivation.

Methods:

A neuronavigation-assisted single transseptal biventricular catheter implantation with distal peritoneal shunt system was performed in 11 patients with posthemorrhagic hydrocephalus and accentuated lateral ventricles dilatations between 2001 and 2010. Patients with concomitant third ventricle dilatation were excluded. Several sequential frustrated attempts of temporary drainage occlusion on both sides confirmed the isolation of the lateral ventricles. Neuronavigation was employed to accurately establish the catheter surgical corridor (trajectory) across the lateral ventricles and throughout the septum pellucidum. The neurological and radiological outcomes were assessed at least 6 months after the procedure.

Results:

Catheter implantation was successfully performed in all patients. Only one catheter was found to be monoventricular on delayed computer tomography controls. Procedure-related complications (bleeding of infections) were not observed. No additional neurological deficits were found after shunt surgery. Six months after procedure, none required additional ventricular catheter implantations or shunt revisions. Radiological and clinical controls confirmed the shunt function and the improved neurological status of all patients.

Conclusion:

Single neuronavigation-assisted transseptal-implanted biventricular catheter is a valid option for the treatment of posthemorrhagic hydrocephalus with accentuated lateral ventricles dilatation. This technique reduces the number of catheters and minimizes the complexity and timing of the surgical procedure as well as potential infection's risks associated with the use of multiple shunting systems.

Cerebrovasospasm following endoscopic cerebrospinal fluid leak repair

Endoscopic repair of spinal fluid leaks is a commonly performed procedure with low morbidity. However, this is the first report of cerebrovasospasm, following endoscopic repair of a cerebrospinal fluid (CSF) leak. A 51-year-old woman underwent endoscopic repair of a spontaneous CSF leak. She subsequently developed symptomatic cerebrovasospasm on postoperative day 3. This was successfully treated with intraarterial verapamil infusion.

Role of iron in brain injury after intraventricular hemorrhage

BACKGROUND AND PURPOSE

Intraventricular extension of hemorrhage is a predictor of poor outcome in intracerebral hemorrhage, and iron overload contributes to brain injury after intracerebral hemorrhage. The current study investigated the role of iron in ventricular dilatation and neuronal death in a rat model of intraventricular hemorrhage (IVH).

METHODS

There were 2 parts in this study. First, male Sprague-Dawley rats had a 200-μL injection of either autologous blood or saline into the right lateral ventricle and were euthanized at different time points. Rats had MRI and brains were used for Western blot analysis, immunohistochemistry, histology, and brain tissue nonheme iron measurements. Second, rats had IVH and were treated with deferoxamine or vehicle, and rats were euthanized 4 weeks later for brain tissue loss and lateral ventricle size measurements.

RESULTS

IVH resulted in brain iron accumulation, bilateral enlargement of the lateral ventricles, and hippocampal brain tissue loss. Iron accumulation was associated with upregulation of heme oxygenase-1 and ferritin. Systemic deferoxamine treatment reduced IVH-induced ventricular enlargement (eg, day 28: 32.7±10.6 vs 43.8±9.7 mm(3) in vehicle-treated group, n=8 to 9; P<0.05) and hippocampal brain tissue loss (hippocampal volume: 89.0±2.7 vs 85.2±4.1 mm(3) in the vehicle-treated group; P<0.05).

CONCLUSIONS

Iron has a role in brain injury after IVH. Deferoxamine may be a therapy for patients with IVH or intraventricular extension after intracerebral hemorrhage.

Predisposing factors related to shunt-dependent chronic hydrocephalus after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Hydrocephalus is a common sequelae of aneurysmal subarachnoid hemorrhage (SAH) and patients who develop hydrocephalus after SAH typically have a worse prognosis than those who do not. This study was designed to identify factors predictive of shunt-dependent chronic hydrocephalus among patients with aneurysmal SAH, and patients who require permanent cerebrospinal fluid diversion.

METHODS

Seven-hundred-and-thirty-four patients with aneurysmal SAH who were treated surgically between 1990 and 2006 were retrospectively studied. Three stages of hydrocephalus have been categorized in this paper, i.e., acute (0-3 days after SAH), subacute (4-13 days after SAH), chronic (>/=14 days after SAH). Criteria indicating the occurrence of hydrocephalus were the presence of significantly enlarged temporal horns or ratio of frontal horn to maximal biparietal diameter more than 30% in computerized tomography.

RESULTS

Overall, 66 of the 734 patients (8.9%) underwent shunting procedures for the treatment of chronic hydrocephalus. Statistically significant associations among the following factors and shunt-dependent chronic hydrocephalus were observed. (1) Increased age (p < 0.05), (2) poor Hunt and Hess grade at admission (p < 0.05), (3) intraventricular hemorrhage (p < 0.05), (4) Fisher grade III, IV at admission (p < 0.05), (5) radiological hydrocephalus at admission (p < 0.05), and (6) post surgery meningitis (p < 0.05) did affect development of chronic hydrocephalus. However the presence of intracerebral hemorrhage, multiple aneurysms, vasospasm, and gender did not influence on the development of shunt-dependent chronic hydrocephalus. In addition, the location of the ruptured aneurysms in posterior cerebral circulation did not correlate with the development of shunt-dependent chronic hydrocephalus.

CONCLUSION

Hydrocephalus after aneurysmal SAH seems to have a multifactorial etiology. Understanding predisposing factors related to the shunt-dependent chronic hydrocephalus may help to guide neurosurgeons for better treatment outcomes.

Prediction of symptomatic cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage: relationship to cerebral salt wasting syndrome

OBJECTIVES

Symptomatic cerebral vasospasm is a major complication in patients with subarachnoid hemorrhage (SAH). Symptomatic cerebral vasospasm has been reported to be related to the patient's blood volume which is influenced by cerebral salt wasting syndrome (CSWS). We undertook a prospective study to assess whether the onset of symptomatic cerebral vasospasm was predictable or not, by observing the phenomena of CSWS (natriuresis and osmotic diuresis).

METHODS

Sixty-seven consecutive aneurysmal SAH patients were analysed. After surgery, all patients underwent hypervolemic therapy in order to keep central venous pressure (CVP) within 8-12 cmH(2)O, serum sodium level above 140 mEq/l and a positive water balance. Patients were classified into two groups: those without symptomatic cerebral vasospasm (n=55) and those with symptomatic cerebral vasospasm (n=12). To estimate natriuresis and osmotic diuresis, sodium in/out, water in/out, CVP and other parameters were measured and compared between the two groups.

RESULTS

One day before symptomatic cerebral vasospasm, three factors reached statistical difference in the group that experienced symptomatic cerebral vasospasm: sodium balance, urine volume and water balance. On the day of symptomatic cerebral vasospasm, two factors reached statistical difference: sodium excretion and urine volume. No factor was significantly different 2 days before symptomatic cerebral vasospasm.

DISCUSSION

Symptomatic cerebral vasospasm has a strong relationship with CSWS. Negative sodium and water balance and increased urine volume indicate a predictor of symptomatic cerebral vasospasm. To predict symptomatic cerebral vasospasm, strict observations are required, because CSWS and symptomatic cerebral vasospasm which follows, develop rapidly.

Activation of cerebral peroxisome proliferator-activated receptors gamma exerts neuroprotection by inhibiting oxidative stress following pilocarpine-induced status epilepticus

Status epilepticus (SE) can cause severe neuronal loss and oxidative damage. As peroxisome proliferator-activated receptor gamma (PPARgamma) agonists possess antioxidative activity, we hypothesize that rosiglitazone, a PPARgamma agonist, might protect the central nervous system (CNS) from oxidative damage in epileptic rats. Using a lithium-pilocarpine-induced SE model, we found that rosiglitazone significantly reduced hippocampal neuronal loss 1 week after SE, potently suppressed the production of reactive oxygen species (ROS) and lipid peroxidation. We also found that treatment with rosiglitazone enhanced antioxidative activity of superoxide dismutase (SOD) and glutathione hormone (GSH), together with decreased expression of heme oxygenase-1 (HO-1) in the hippocampus. The above effects of rosiglitazone can be blocked by co-treatment with PPARgamma antagonist T0070907. The current data suggest that rosiglitazone exerts a neuroprotective effect on oxidative stress-mediated neuronal damage followed by SE. Our data also support the idea that PPARgamma agonist might be a potential neuroprotective agent for epilepsy.

Heme, heme oxygenase, and ferritin: how the vascular endothelium survives (and dies) in an iron-rich environment

Iron-derived reactive oxygen species are involved in the pathogenesis of numerous vascular disorders. One abundant source of redox active iron is heme, which is inherently dangerous when it escapes from its physiologic sites. Here, we present a review of the nature of heme-mediated cytotoxicity and of the strategies by which endothelium manages to protect itself from this clear and present danger. Of all sites in the body, the endothelium may be at greatest risk of exposure to heme. Heme greatly potentiates endothelial cell killing mediated by leukocytes and other sources of reactive oxygen. Heme also promotes the conversion of low-density lipoprotein to cytotoxic oxidized products. Hemoglobin in plasma, when oxidized, transfers heme to endothelium and lipoprotein, thereby enhancing susceptibility to oxidant-mediated injury. As a defense against such stress, endothelial cells upregulate heme oxygenase-1 and ferritin. Heme oxygenase opens the porphyrin ring, producing biliverdin, carbon monoxide, and a most dangerous product-redox active iron. The latter can be effectively controlled by ferritin via sequestration and ferroxidase activity. These homeostatic adjustments have been shown to be effective in the protection of endothelium against the damaging effects of heme and oxidants; lack of adaptation in an iron-rich environment led to extensive endothelial damage in humans.

Lactate Contents From Cerebrospinal Fluid in Experimental Subarachnoid Hemorrhage, Well Correlate With Vasospasm

The role of lactate composition of cerebrospinal fluid (CSF) with vasospasm severity and rabbit neurologic status in subarachnoid hemorrhage was determined. The neurologic status of 20 New Zealand rabbits were graded initially and then, anesthetized and basal angiograms were performed. Then 1.0 mL of CSF was withdrawn through cisterna magna and then 1 mL autologous arterial blood was injected in all rabbits over 1 minute. After 5 days, neurologic severity score (NSS) and vertebrobasilar angiograms of all rabbits were repeated. Rabbits without radiologic vasospasm or spasm under 50% (n=7) were termed as group 1. Rabbits whose cerebral vasospasm were 50% or over 50% (n=7) and NSS is lesser than 3 were termed as groups 2, and rabbits whose cerebral vasospasm were 50% or above 50% (n=7) and NSS is greater than 3 were termed groups 3. On day 7, the CSF lactate values of each group were significantly different (P<0.05) with each other. But when compared with only CSF baseline lactate values groups 2 and 3 were significantly different (P<0.05). However, the NSSs were similar in groups 1 and 2, but group 3 significantly differed from groups 1 and 2 (P<0.05). All groups significantly differed from baseline NSSs (P<0.05). The data showed clearly that the degree of vasospasm correlates not only with neurologic status but also with CSF lactate levels. We suggest that CSF lactate level may be useful as a surrogate marker of cerebral vasospasm degree after subarachnoid hemorrhage in clinics where invasive cerebral angiography could not be assessed for whatever reasons.

Endovascular management of intracranial aneurysms: current experience and future advances

OBJECTIVE

The past 15 years have seen a revolution in the treatment of intracranial aneurysms. Endovascular technology has evolved rapidly since the Food and Drug Administration approval of Guglielmi detachable coils in 1995, which now allows successful treatment of most aneurysms. The authors provide a review of their 11-year experience at Jefferson Hospital for Neuroscience with endovascular embolization of intracranial aneurysms and discuss clinical trial outcomes and future directions of this treatment method.

METHODS

The authors reviewed the clinical and angiographic outcomes for 1307 patients undergoing endovascular treatment of intracranial aneurysms. Their analysis focuses on posterior circulation and middle cerebral artery aneurysms, as well as cases of stent-assisted coil embolization. They review their procedural protocol and patient selection criteria for endovascular management.

RESULTS

Several large clinical trials have demonstrated the safety and efficacy of endovascular treatment of intracranial aneurysms. The International Subarachnoid Aneurysm Trial provides Level I evidence demonstrating a significant reduction in disability or death with endovascular treatment compared with surgical clipping. The most common procedural complications include intraprocedural rupture and thromboembolic events; avoidance strategies are also discussed. Vasospasm after subarachnoid hemorrhage causes neurological morbidity and mortality and can be successfully managed by early recognition and interventional treatment with angioplasty, pharmacologic agents, or both.

CONCLUSION

Long-term studies evaluating experience with aneurysm coil embolization during the past decade indicate that this is a safe and durable treatment method. The introduction of stent-assist techniques has improved the management of wide-neck aneurysms. Future technology developments will likely improve the durability of endovascular treatment further by delivering bioactive agents that promote aneurysm thrombosis beyond the coil mass alone. It is clear that endovascular therapy of both ruptured and unruptured aneurysms is becoming a mainstay of practice in this patient population. Although not replacing open surgery, the continued improvements have allowed aneurysms that previously were amenable only to open clip ligation to be treated safely with durable long-term outcomes.

Clinical review: Prevention and therapy of vasospasm in subarachnoid hemorrhage

Vasospasm is one of the leading causes of morbidity and mortality following aneurysmal subarachnoid hemorrhage (SAH). Radiographic vasospasm usually develops between 5 and 15 days after the initial hemorrhage, and is associated with clinically apparent delayed ischemic neurological deficits (DID) in one-third of patients. The pathophysiology of this reversible vasculopathy is not fully understood but appears to involve structural changes and biochemical alterations at the levels of the vascular endothelium and smooth muscle cells. Blood in the subarachnoid space is believed to trigger these changes. In addition, cerebral perfusion may be concurrently impaired by hypovolemia and impaired cerebral autoregulatory function. The combined effects of these processes can lead to reduction in cerebral blood flow so severe as to cause ischemia leading to infarction. Diagnosis is made by some combination of clinical, cerebral angiographic, and transcranial doppler ultrasonographic factors. Nimodipine, a calcium channel antagonist, is so far the only available therapy with proven benefit for reducing the impact of DID. Aggressive therapy combining hemodynamic augmentation, transluminal balloon angioplasty, and intra-arterial infusion of vasodilator drugs is, to varying degrees, usually implemented. A panoply of drugs, with different mechanisms of action, has been studied in SAH related vasospasm. Currently, the most promising are magnesium sulfate, 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, nitric oxide donors and endothelin-1 antagonists. This paper reviews established and emerging therapies for vasospasm.

Regulation of heme oxygenase-1 gene expression through the phosphatidylinositol 3-kinase/PKC-zeta pathway and Sp1

The molecular mechanisms involved in modulation of the antioxidant cell defence by survival signals remain largely unexplored. Here, we report a mechanistic connection between the survival signal elicited by nerve growth factor (NGF) and the antioxidant cell defence represented by heme oxygenase-1 (HO-1) at the level of a newly identified Sp1 site in the human ho1 proximal promoter. By using luciferase reporter constructs we identified a PI3K-responsive region containing a GC-box that resembled the response element for Sp1. Indeed, transfection of Sp1-deficient SL2 cells, electrophoretic mobility shift assays, the use of the GC-box binding drug mithramycin, and mutation of the GC-box provided evidence for a Sp1-like site in the PI3K-sensitive region. Then, we observed with the use of a Sp1-Gal4 chimera that PI3K regulates the transactivating capacity of Sp1. Cotransfection of active PI3K and PKC-zeta expression vectors resulted in substantial increase of Sp1 phosphorylation and in synergistic activation of both Sp1-Gal4 and endogenous Sp1. Moreover, these effects were mimicked by cotransfection of active MEK and ERK expression vectors and were blocked by the MEK inhibitor PD98059. Inhibition of HO-1 with Sn protoporphyrin IX and blockage of Sp-1-mediatied upregulation of HO-1 with mithramycin attenuated antioxidant and cytoprotective functions of NGF against hydrogen peroxide. This study elucidates how NGF contributes to protection of target cells against oxidative stress.

Cerebrospinal fluid ferritin in chronic hydrocephalus after aneurysmal subarachnoid hemorrhage

OBJECTIVES

Subarachnoid hemorrhage (SAH) is a common cause of chronic hydrocephalus. Blood in the subarachnoid space is intracranially metabolized to bilirubin and iron, and free iron is thereafter detoxified by ferritin. However, no studies have reported the relationship between intracranial heme metabolism and chronic hydrocephalus after SAH. The goal of this prospective study was to clarify the relationship between intracranial heme metabolism and chronic hydrocephalus after SAH.

METHODS

The authors measured the levels of bilirubin, iron and ferritin in the cerebrospinal fluid (CSF) of 70 consecutive patients with aneurysmal SAH of Fisher computed tomography Group III, and determined the relationship between these substances' levels and hydrocephalus requiring ventriculoperitoneal shunting.

RESULTS

The CSF concentrations of ferritin and inflammatory cells were significantly higher in shunted patients (n = 27) than in non-shunted patients (n = 43) on Days 3 and 4 (p < 0.05 in ferritin and p < 0.01 in inflammatory cells) and 11 to 14 (p < 0.005 in ferritin) post-SAH. These results were independent of other clinical factors. The occurrence of chronic hydrocephalus was not affected by the extent of the intracranial heme metabolism in terms of the bilirubin and iron levels.

CONCLUSIONS

This is the first study to show that patients who subsequently had chronic hydrocephalus requiring CSF shunting were associated with higher CSF levels of ferritin in the acute stage of SAH. Higher CSF ferritin levels may not reflect the amount of blood in the subarachnoid space that was intracranially metabolized, but rather more intense subarachnoid inflammatory reactions which may cause chronic hydrocephalus after SAH.

Heme, heme oxygenase and ferritin in vascular endothelial cell injury

Iron-derived reactive oxygen species are implicated in the pathogenesis of numerous vascular disorders including atherosclerosis, microangiopathic hemolytic anemia, vasculitis, and reperfusion injury. One abundant source of redox active iron is heme, which is inherently dangerous when released from intracellular heme proteins. The present review concerns the involvement of heme in vascular endothelial cell damage and the strategies used by endothelium to minimize such damage. Exposure of endothelium to heme greatly potentiates cell killing mediated by polymorphonuclear leukocytes and other sources of reactive oxygen. Free heme also promotes the conversion of low-density lipoprotein (LDL) into cytotoxic oxidized products. Only because of its abundance, hemoglobin probably represents the most important potential source of heme within the vascular endothelium; hemoglobin in plasma, when oxidized, transfers heme to endothelium and LDL, thereby enhancing cellular susceptibility to oxidant-mediated injury. As a defense against such toxicity, upon exposure to heme or hemoglobin, endothelial cells up-regulate heme oxygenase-1 and ferritin. Heme oxygenase-1 is a heme-degrading enzyme that opens the porphyrin ring, producing biliverdin, carbon monoxide, and the most dangerous product - free redox active iron. The latter can be effectively controlled by ferritin via sequestration and ferroxidase activity. Ferritin serves as a protective gene by virtue of antioxidant, antiapoptotic, and antiproliferative actions. These homeostatic adjustments have been shown effective in the protection of endothelium against the damaging effects of exogenous heme and oxidants. The central importance of this protective system was recently highlighted by a child diagnosed with heme oxygenase-1 deficiency, who exhibited extensive endothelial damage.

Bilirubin production and oxidation in CSF of patients with cerebral vasospasm after subarachnoid hemorrhage

Delayed cerebral vasospasm after subarachnoid hemorrhage (SAH) remains a significant cause of mortality and morbidity; however, the etiology is, as yet, unknown, despite intensive research efforts. Research in this laboratory indicates that bilirubin and oxidative stress may be responsible by leading to formation of bilirubin oxidation products (BOXes), so we investigated changes in bilirubin concentration and oxidative stress in vitro, and in cerebral spinal fluid (CSF) from SAH patients. Non-SAH CSF, a source of heme oxygenase I (HO-1), and blood were incubated, and in vitro bilirubin production measured. Cerebrospinal fluid from SAH patients was collected, categorized using stimulation of vascular smooth muscle metabolism in vitro, and information obtained regarding occurrence of vasospasm in the patients. Cerebral spinal fluid was analyzed for hemoglobin, total protein and bilirubin, BOXes, malonyldialdehyde and peroxidized lipids (indicators of an oxidizing environment), and HO-1 concentration. The formation of bilirubin in vitro requires that CSF is present, as well as whole, non-anti-coagulated blood. Bilirubin, BOXes, HO-1, and peroxidized lipid content were significantly higher in CSF from SAH patients with vasospasm, compared with nonvasospasm SAH CSF, and correlated with occurrence of vasospasm. We conclude that vasospasm may be more likely in patients with elevated BOXes. The conditions necessary for the formation of BOXes are indeed present in CSF from SAH patients with vasospasm, but not CSF from SAH patients without vasospasm.

Heme oxygenase expression in human central nervous system disorders

In the normal mammalian CNS, heme oxygenase-2 (HO-2) is constitutively, abundantly, and fairly ubiquitously expressed, whereas heme oxygenase-1 (HO-1) mRNA and protein are confined to small populations of scattered neurons and neuroglia. Unlike ho-2, the ho-1 gene in neural (and many systemic) tissues is exquisitely sensitive to upregulation by a host of pro-oxidant and other noxious stimuli. In Alzheimer disease, HO-1 immunoreactivity is significantly augmented in neurons and astrocytes of the hippocampus and cerebral cortex relative to age-matched, nondemented controls and colocalizes to senile plaques, neurofibrillary tangles, and corpora amylacea. In Parkinson disease, HO-1 decorates Lewy bodies of affected dopaminergic neurons and is highly overexpressed in astrocytes residing within the substantia nigra. The ho-1 gene is also upregulated in glial cells within multiple sclerosis plaques; in the vicinity of human cerebral infarcts, hemorrhages, and contusions; and in various other degenerative and nondegenerative human CNS disorders. The products of the heme oxygenase reaction, free ferrous iron, carbon monoxide, and biliverdin/bilirubin, are all biologically active molecules that may profoundly influence tissue redox homeostasis under a wide range of pathophysiological conditions. Evidence adduced from whole animal and in vitro studies indicates that enhanced HO-1 activity may either ameliorate or exacerbate neural injury, effects likely contingent upon the specific model employed, the duration and intensity of HO-1 induction, and the chemistry of the local redox microenvironment. HO-1 hyperactivity also promotes mitochondrial sequestration of nontransferrin iron in oxidatively challenged astroglia and may thereby contribute to the pathological iron deposition and bioenergetic failure amply documented in aging and degenerating human neural tissues.

Development of Drug Delivery System for Intrathecal Administration and Its Therapeutic Effect on Cerebral Vasospasm and Ischemia

To date, the pharmacologic approach to cerebral vasospasm and ischemia has been hampered in part by an inability to attain sufficiently high concentrations of drugs in the cerebrospinal fluid (CSF). To overcome this limitation of current drug therapy, we have developed a sustained-release preparation of the protein kinase inhibitor fasudil. Experimental cerebral vasospasm in rats and dogs was induced by double injection of autologous arterial blood into the cisterna magna. Focal cerebral ischemia in rats was induced by middle cerebral artery occlusion using an intraluminal suture technique. A single intrathecal injection of liposomal fasudil can maintain a therapeutic the drug concentration in the CSF due to the sustained-release property of liposomes, significantly decreasing intact size of acute ischemia and decreasing vasoconstriction of the basilar artery in cerebral vasospasm. This novel approach for the treatment of cerebral vasospasm and ischemia may have significant potential for use in the clinical setting.