Endothelial Nitric Oxide Synthase Polymorphism Is Associated with Delayed Cerebral Ischemia Following Aneurysmal Subarachnoid Hemorrhage

Immunological Profile of Vasospasm after Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) carries high mortality and disability rates, which are substantially driven by complications. Early brain injury and vasospasm can happen after SAH and are crucial events to prevent and treat to improve prognosis. In recent decades, immunological mechanisms have been implicated in SAH complications, with both innate and adaptive immunity involved in mechanisms of damage after SAH. The purpose of this review is to summarize the immunological profile of vasospasm, highlighting the potential implementation of biomarkers for its prediction and management. Overall, the kinetics of central nervous system (CNS) immune invasion and soluble factors' production critically differs between patients developing vasospasm compared to those not experiencing this complication. In particular, in people developing vasospasm, a neutrophil increase develops in the first minutes to days and pairs with a mild depletion of CD45+ lymphocytes. Cytokine production is boosted early on after SAH, and a steep increase in interleukin-6, metalloproteinase-9 and vascular endothelial growth factor (VEGF) anticipates the development of vasospasm after SAH. We also highlight the role of microglia and the potential influence of genetic polymorphism in the development of vasospasm and SAH-related complications.

A Review of Genetic Polymorphisms and Susceptibilities to Complications after Aneurysmal Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) and vasospasm are two complications of subarachnoid hemorrhages (SAHs) which entail high risks of morbidity and mortality. However, it is unknown why only some patients who suffer SAHs will experience DCI and vasospasm. The purpose of this review is to describe the main genetic single nucleotide polymorphisms (SNPs) that have demonstrated a relationship with these complications. The SNP of the nitric oxide endothelial synthase (eNOS) has been related to the size and rupture of an aneurysm, as well as to DCI, vasospasm, and poor neurological outcome. The SNPs responsible for the asymmetric dimetilarginine and the high-mobility group box 1 have also been associated with DCI. An association between vasospasm and the SNPs of the eNOS, the haptoglobin, and the endothelin-1 receptor has been found. The SNPs of the angiotensin-converting enzyme have been related to DCI and poor neurological outcome. Studies on the SNPs of the Ryanodine Receptor yielded varying results regarding their association with vasospasm.

Enhancing S-nitrosoglutathione reductase decreases S-nitrosylation of Drp1 and reduces neuronal apoptosis in experimental subarachnoid hemorrhage both in vivo and in vitro

Subarachnoid hemorrhage (SAH) is a hemorrhagic stroke with a high mortality and disability rate. Nitric oxide (NO) can promote blood supply through vasodilation, leading to protein S-nitrosylation. However, the function of S-nitrosylation in neurons after SAH remains unclear. Excessive NO in the pathological state is converted into S-nitrosoglutathione (GSNO) and stored in cells, which leads to high S-nitrosylation of intracellular proteins and causes nitrosative stress. S-nitrosoglutathione reductase (GSNOR) promotes GSNO degradation and protects cells from excessive S-nitrosylation. We conducted an in vivo rat carotid puncture model and an in vitro neuron hemoglobin intervention. The results showed that SAH induction increased NO, GSNO, neuron protein S-nitrosylation, and neuronal apoptosis, while decreasing the level and activity of GSNOR. GSNOR overexpression by lentivirus decreased GSNO but had little effect on NO. GSNOR overexpression also improved short- and long-term neurobehavioral outcomes in rats and alleviated nitrosative stress. Furthermore, GSNOR reduced neuronal apoptosis and played a neuroprotective role by alleviating Drp1 S-nitrosylation, reducing mitochondrial division. Thus, the regulation of GSNOR in early brain injury and neuronal denitrosylation may play an important role in neuroprotection.

Meta-analysis of associations of genetic polymorphisms with cerebral vasospasm and delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

INTRODUCTION

Cerebral vasospasm (CV) and delayed cerebral ischemia (DCI) are among the most hazardous complications of aneurysmal subarachnoid hemorrhage (aSAH). Genetic factors are thought to play a significant role in the development of both complications.

AIM

To perform a comprehensive meta-analysis of studies that study the association between different genetic polymorphisms and development of DCI and/or CV.

METHODS

We searched MEDLINE and Science Direct databases on May 29, 2021, using iterations of the keywords "subarachnoid hemorrhage", "vasospasm", "delayed cerebral ischemia", and "gene". After duplicates were removed, the two reviewers screened the titles of the articles and abstracts independently. A random-effect model was used to calculate the relative risk with 95% CI; a fixed-effect model was additionally explored.

RESULTS

We pooled data from 16 articles that reported an association between eNOS, apolipoprotein E4 (ApoE4), haptoglobin (Hp), or ryanodine-1 (RYR-1) and CV, DCI, or both. Presence of Hp 2-2 was associated both with CV (RR 2.10, 95% CI 1.33-3.31, p = 0.0014) and DCI (RR 1.57, 95%CI 1.06-2.34, p = 0.026). ApoE4 allele had a borderline association with CV (RR 1.48, 95%CI 0.99-2.21, p = 0.054).

CONCLUSION

Our meta-analysis supports the association between the presence of the Hp2-2 allele and the occurrence of CV and DCI after aSAH. Further studies investigating this association are needed to reinforce this finding.

Common Endothelial Nitric Oxide Synthase Single Nucleotide Polymorphisms are not Related With the Risk for Restless Legs Syndrome

Because nitric oxide and endothelial dysfunction could play a role in the pathogenesis of idiopathic restless legs syndrome (RLS), as was suggested by some preliminary data, we investigated the possible association between the rs2070744 variants in the endothelial nitric oxide synthase (eNOS or NOS3) gene (chromosome 7q36.1) and the risk for RLS in a Caucasian Spanish population. We assessed the frequencies of NOS3 single nucleotide polymorphisms (SNPs) rs2070744, rs1799983, and rs79467411 genotypes and allelic variants in 273 patients with idiopathic RLS and 325 healthy controls using a TaqMan-based qPCR assay. We also analyzed the possible influence of genotype frequency on age at onset of RLS symptoms, gender, family history of RLS, and response to drugs commonly used in the treatment of RLS such as dopaminergic drugs, clonazepam, and GABAergic drugs. The frequencies of genotypes and allelic variants were not associated with the risk for RLS and were not influenced by gender, age, and positive family history of RLS. We identified weak statistical associations of the SNP rs1799983 with the response to dopamine agonists (Pc = 0.018 for the rs1799983 G/T genotype) and of the SNP rs79467411 with the response to clonazepam (Pc = 0.018 for the rs79467411 G allele), although these findings should be cautiously interpreted and require further confirmation. These associations aside, our findings suggest that common NOS3 SNPs are not associated with the risk for idiopathic RLS in Caucasian Spanish people.

Sequence Variation in the DDAH1 Gene Predisposes for Delayed Cerebral Ischemia in Subarachnoidal Hemorrhage

Delayed cerebral ischemia (DCI) often causes poor long-term neurological outcome after subarachnoidal hemorrhage (SAH). Asymmetric dimethylarginine (ADMA) inhibits nitric oxide synthase (NOS) and is associated with DCI after SAH. We studied single nucleotide polymorphisms (SNPs) in the NOS3, DDAH1, DDAH2, PRMT1, and AGXT2 genes that are part of the L-arginine–ADMA–NO pathway, and their association with DCI. We measured L-arginine, ADMA and symmetric dimethylarginine (SDMA) in plasma and cerebrospinal fluid (CSF) of 51 SAH patients at admission; follow-up was until 30 days post-discharge. The primary outcome was the incidence of DCI, defined as new infarctions on cranial computed tomography, which occurred in 18 of 51 patients. Clinical scores did not significantly differ in patients with or without DCI. However, DCI patients had higher plasma ADMA and SDMA levels and higher CSF SDMA levels at admission. DDAH1 SNPs were associated with plasma ADMA, whilst AGXT2 SNPs were associated with plasma SDMA. Carriers of the minor allele of DDAH1 rs233112 had a significantly increased relative risk of DCI (Relative Risk = 2.61 (1.25–5.43), p = 0.002). We conclude that the DDAH1 gene is associated with ADMA concentration and the incidence of DCI in SAH patients, suggesting a pathophysiological link between gene, biomarker, and clinical outcome in patients with SAH.

Nomogram for predicting delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage in the Chinese population

BACKGROUND

Delayed cerebral ischemia is a serious complication of aneurysmal subarachnoid hemorrhage with debilitating and fatal consequences. Lack of well-established risk factors impedes early identification of high-risk patients with delayed cerebral ischemia. A nomogram provides personalized, evidence-based, and accurate risk estimation. To offset the lack of a predictive tool, we developed a nomogram to predict delayed cerebral ischemia before performing surgical interventions for aneurysmal subarachnoid hemorrhage to aid surgical decision-making.

METHODS

We retrospectively collected data from 887 consecutive eligible Chinese patients who underwent surgical clipping or endovascular coiling for aneurysmal subarachnoid hemorrhage. Patients who previously underwent surgery formed the training cohort (n = 621) for nomogram development; those who underwent surgery later formed the validation cohort (n = 266) to confirm the performance of the model. A multivariate logistic regression analysis identified the independent risk factors associated with delayed cerebral ischemia, which were then incorporated into the nomogram.

RESULTS

Delayed cerebral ischemia was identified in 158/621 patients (25.4%) in the training cohort and in 66/266 patients (24.8%) in the validation cohort. Preoperative factors associated with delayed cerebral ischemia were age > 65 years, modified Fisher grade of 3-4, ruptured aneurysm in the anterior circulation, Hunt-Hess grade of 4-5, high blood pressure on admission, and plasma homocysteine level ≥ 10 μmol/L. Incorporating these six factors in the nomogram achieved efficient concordance indices of 0.73 (95% confidence interval, 0.68-0.77) and 0.65 (95% confidence interval, 0.57-0.72) in predicting delayed cerebral ischemia in the training and validation cohorts, respectively.

CONCLUSIONS

Our model can help determine an individual's risk of developing delayed cerebral ischemia in the Chinese population, and thereby, facilitate reasonable treatment-related decision-making.

Oxidative Stress-Mediated Blood-Brain Barrier (BBB) Disruption in Neurological Diseases

The blood-brain barrier (BBB), as a crucial gate of brain-blood molecular exchange, is involved in the pathogenesis of multiple neurological diseases. Oxidative stress is caused by an imbalance between the production of reactive oxygen species (ROS) and the scavenger system. Since oxidative stress plays a significant role in the production and maintenance of the BBB, the cerebrovascular system is especially vulnerable to it. The pathways that initiate BBB dysfunction include, but are not limited to, mitochondrial dysfunction, excitotoxicity, iron metabolism, cytokines, pyroptosis, and necroptosis, all converging on the generation of ROS. Interestingly, ROS also provide common triggers that directly regulate BBB damage, parameters including tight junction (TJ) modifications, transporters, matrix metalloproteinase (MMP) activation, inflammatory responses, and autophagy. We will discuss the role of oxidative stress-mediated BBB disruption in neurological diseases, such as hemorrhagic stroke, ischemic stroke (IS), Alzheimer’s disease (AD), Parkinson’s disease (PD), traumatic brain injury (TBI), amyotrophic lateral sclerosis (ALS), and cerebral small vessel disease (CSVD). This review will also discuss the latest clinical evidence of potential biomarkers and antioxidant drugs towards oxidative stress in neurological diseases. A deeper understanding of how oxidative stress damages BBB may open up more therapeutic options for the treatment of neurological diseases.

Endothelial nitric oxide synthase (NOS3) rs2070744 polymorphism and risk for multiple sclerosis

The possible role of oxidative stress and nitric oxide (NO) in the pathogenesis of multiple sclerosis (MS) has been suggested by several neuropathological, biochemical, and experimental data. Because the single-nucleotide polymorphism (SNP) rs2070744 in the endothelial nitric oxide synthase (eNOS or NOS3) gene (chromosome 7q36.1) showed association with the risk for MS in Iranians, we attempted to replicate the possible association between this SNP and the risk for MS in the Caucasian Spanish population. The frequencies of NOS3rs2070744 genotypes and allelic variants in 300 patients diagnosed with MS and 380 healthy controls were assessed with a TaqMan-based qPCR assay. The possible influence of the genotype frequency on age at onset of MS, the severity of MS, clinical evolutive subtypes of MS, and HLA-DRB1*1501 genotype were also analyzed. The frequencies of rs2070744 genotypes and allelic variants were not associated with the risk of developing MS and were not influenced by gender, age at onset and severity of MS, the clinical subtype of MS or the HLA-DRB1*1501 genotype. This study found a lack of association between NOS3 rs2070744 SNP and the risk for MS in Caucasian Spanish people.

Genetic Factors of Nitric Oxide's System in Psychoneurologic Disorders

According to the recent data, nitric oxide (NO) is a chemical messenger that mediates functions such as vasodilation and neurotransmission, as well as displaying antimicrobial and antitumoral activities. NO has been implicated in the neurotoxicity associated with stroke and neurodegenerative diseases; neural regulation of smooth muscle, including peristalsis; and penile erections. We searched for full-text English publications from the past 15 years in Pubmed and SNPedia databases using keywords and combined word searches (nitric oxide, single nucleotide variants, single nucleotide polymorphisms, genes). In addition, earlier publications of historical interest were included in the review. In our review, we have summarized information regarding all NOS1, NOS2, NOS3, and NOS1AP single nucleotide variants (SNVs) involved in the development of mental disorders and neurological diseases/conditions. The results of the studies we have discussed in this review are contradictory, which might be due to different designs of the studies, small sample sizes in some of them, and different social and geographical characteristics. However, the contribution of genetic and environmental factors has been understudied, which makes this issue increasingly important for researchers as the understanding of these mechanisms can support a search for new approaches to pathogenetic and disease-modifying treatment.

Genetic drivers of cerebral blood flow dysfunction in TBI: a speculative synthesis

Cerebral autoregulatory dysfunction after traumatic brain injury (TBI) is strongly linked to poor global outcome in patients at 6 months after injury. However, our understanding of the drivers of this dysfunction is limited. Genetic variation among individuals within a population gives rise to single-nucleotide polymorphisms (SNPs) that have the potential to influence a given patient's cerebrovascular response to an injury. Associations have been reported between a variety of genetic polymorphisms and global outcome in patients with TBI, but few studies have explored the association between genetic variants and cerebrovascular function after injury. In this Review, we explore polymorphisms that might play an important part in cerebral autoregulatory capacity after TBI. We outline a variety of SNPs, their biological substrates and their potential role in mediating cerebrovascular reactivity. A number of candidate polymorphisms exist in genes that are involved in myogenic, endothelial, metabolic and neurogenic vascular responses to injury. Furthermore, polymorphisms in genes involved in inflammation, the central autonomic response and cortical spreading depression might drive cerebrovascular reactivity. Identification of candidate genes involved in cerebral autoregulation after TBI provides a platform and rationale for further prospective investigation of the link between genetic polymorphisms and autoregulatory function.

Association between endothelial nitric oxide synthase (NOS3) rs2070744 and the risk for migraine

Because nitric oxide could play an important role in the pathogenesis of migraine (suggested by experimental, neuropathological, biochemical, and pharmacological data), and a recent meta-analysis showed an association between the single-nucleotide polymorphism (SNP) rs2070744 in the endothelial nitric oxide synthase (eNOS or NOS3) gene (chromosome 7q36.1) and the risk for migraine in Caucasians, we attempted to replicate the possible association between this SNP and the and the risk for migraine in the Caucasian Spanish population. The frequencies for the NOS3 rs2070744 genotypes and allelic variants were assessed in 283 migraine patients and 287 healthy controls with a TaqMan-based qPCR Assay. The putative influence on genotype frequency of age at onset of migraine attacks, gender, family history of migraine, absence or presence of aura, and triggering of migraine attacks by ethanol, were also analyzed. The frequencies of NOS3 rs2070744 genotypes and allelic variants were not associated with the risk for migraine (OR [95%] CI for the minor allele = 0.91 [0.72-1.15]) and were not influenced by age at onset of migraine, gender, presence of aura, or triggering of migraine attacks by ethanol. NOS3 rs2070744CC genotypes were significantly more frequent in patients with a family history of migraine. NOS3 rs2070744 SNP is not associated with the risk for migraine in Caucasian Spanish people although it might be related to family history.

The Correlation of Endothelial Nitric Oxide Synthase (eNOS) Polymorphism and Other Risk Factors with Aneurysmal Subarachnoid Hemorrhage: A Case-Control Study

Objective

Endothelial nitric oxide synthase gene (eNOS) polymorphism is an association with cerebral aneurysm formation, rupture, and vasospasm and plays a role in the a functional outcome.

Patients and Methods

The aim of the study was to evaluate the role of eNOS gene polymorphism and further assess the predictors of outcome in the aneurysmal subarachnoid hemorrhage (aSAH). A prospective case-control study was conducted from 2009 to 2012 among those who presented with aSAH. A serum sample was collected from aSAH patients along with age and sex-matched healthy controls. The frequency of polymorphism of eNOS gene and other factors (demographic and aneurysmal) were correlated with functional outcome at six month of follow-up.

Results

100 patients with aSAH and 100 healthy controls were enrolled in the cohort. The mean age of the patient group was 51.61 years and control group was 45.81 years with a male:female ratio of 1:1.38 and 1:1.08 for patients and controls, respectively. Among all eNOS polymorphisms, 4BB (65%) 24-VNTR, TT (71%) of T-786C, and GG (71%) of G947T were the most common and frequency was similar in the control group. The occurrences of hypertension, smoking, diabetes were 32%, 37%, and 7% respectively in the patient group. Maximum patients were in WFNS grade 1 (53%) followed by 23% grade 2 and only 10% in grade 4. Fisher grade 3 (57%) was the most common followed by Fisher grade 4 (28%). Most aneurysms (97%) were in anterior circulation. 83% of the aneurysms were clipped and 10% underwent coiling. Size-wise most of the aneurysms were in the middle group (6-9 mm) followed by bigger group (>10 mm) (37%); only 6% aneurysms were in the small aneurysm (<6 mm) group. 33% of the patients had evidence of vasospasm. TT of G894T polymorphism (60%) had the highest incidence of vasospasm. Univariate analysis showed smoking (OR: 3.19, CI: 1.19-8.84, P = 0.01), 4AA (OR: 12.15, CI: 1.13-624.9, P = 0.03) variety of 24-VNTR polymorphism, CC (OR: 15.39, CI: 1.60-762.8, P = 0.01) variety of T786C polymorphism, Fisher grade 4 (OR: 3.43, CI: 1.24-9.68, P = 0.01), WFNS grade (poor vs. good) (OR: 3.42, CI: 1.17-10.12, P = 0.02), vasospasm (OR: 3.84, CI: 1.42-10.75, P = 0.006), intraoperative rupture (OR: 4.77, CI: 1.55-15.27, P = 0.004) were significantly related with unfavorable outcome at 6 months follow-up. In regression analysis, smoking (CI: 0.06-0.69, P = 0.01), Fisher grade 4 (CI: 0.09-1.00, P = 0.05), and intraoperative rupture (CI: 0.05-0.89, P = 0.03) were correlated with an unfavorable outcome at 6 months follow-up.

Conclusion

The eNOS gene polymorphism, smoking, clinical grade (WFNS), Fisher grade, intraoperative rupture, and vasospasm play a role in functional outcome after the treatment of cerebral aneurysms.

Genetic basis of intracranial aneurysm formation and rupture: clinical implications in the postgenomic era

OBJECTIVE

Despite the prevalence and impact of intracranial aneurysms (IAs), the molecular basis of their pathogenesis remains largely unknown. Moreover, there is a dearth of clinically validated biomarkers to efficiently screen patients with IAs and prognosticate risk for rupture. The aim of this study was to survey the literature to systematically identify the spectrum of genetic aberrations that have been identified in IA formation and risk of rupture.

METHODS

A literature search was performed using the Medical Subject Headings (MeSH) system of databases including PubMed, EMBASE, and Google Scholar. Relevant studies that reported on genetic analyses of IAs, rupture risk, and long-term outcomes were included in the qualitative analysis.

RESULTS

A total of 114 studies were reviewed and 65 were included in the qualitative synthesis. There are several well-established mendelian syndromes that confer risk to IAs, with variable frequency. Linkage analyses, genome-wide association studies, candidate gene studies, and exome sequencing identify several recurrent polymorphic variants at candidate loci, and genes associated with the risk of aneurysm formation and rupture, including ANRIL (CDKN2B-AS1, 9p21), ARGHEF17 (11q13), ELN (7q11), SERPINA3 (14q32), and SOX17 (8q11). In addition, polymorphisms in eNOS/NOS3 (7q36) may serve as predictive markers for outcomes following intracranial aneurysm rupture. Genetic aberrations identified to date converge on posited molecular mechanisms involved in vascular remodeling, with strong implications for an associated immune-mediated inflammatory response.

CONCLUSIONS

Comprehensive studies of IA formation and rupture have identified candidate risk variants and loci; however, further genome-wide analyses are needed to identify high-confidence genetic aberrations. The literature supports a role for several risk loci in aneurysm formation and rupture with putative candidate genes. A thorough understanding of the genetic basis governing risk of IA development and the resultant aneurysmal subarachnoid hemorrhage may aid in screening, clinical management, and risk stratification of these patients, and it may also enable identification of putative mechanisms for future drug development.

Correlation Between Altered DNA Methylation of Intergenic Regions of ITPR3 and Development of Delayed Cerebral Ischemia in Patients with Subarachnoid Hemorrhage

BACKGROUND

Delayed cerebral ischemia (DCI) is related to the major causes of morbidity and mortality in patients following subarachnoid hemorrhage (SAH); however, little is known about the role of epigenetics in the pathogenesis of DCI. We investigated the specific DNA methylation profile that may affect the expression of inositol 1-,4-,5-trisphosphate receptor (ITPR3) responsible for cerebral vasospasm following SAH.

METHODS

We prospectively studied patients with SAH between March 2015 and October 2018. The degree of methylation in the distal intergenic region (IGR) located on ITPR3 and gene expression were measured using methylation-specific polymerase chain reaction (MSP) and quantitative real-time polymerase chain reaction (qPCR). To investigate the regulatory mechanims of DNA hypermethylation, we further analyzed the mRNA expression of DNA methyltransferase (DNMT1) and ten-eleven translocation enzymes (TET1, TET2, and TET3).

RESULTS

A total of 42 patients were included in our analysis. Patients with SAH and DCI had significantly higher levels of methylation intensity of distal IGR upstream of ITPR3 than those without DCI (median, 0.941 [interquartile range (IQR), 0.857-0.984] versus (0.670 [IQR, 0.543-0.761]; P < 0.001). In addition, patients with DCI showed decreased mRNA expression of ITPR3 compared with patients without DCI (median, 0.039 [IQR, 0.030-0.045] vs. 0.047 [IQR, 0.038-0.064]; P = 0.0328). Patients with DCI had higher DNMT1 expression (P < 0.001) and lower TET1 expression (P = 0.040) than those without DCI; however, differences in TET2 and TET3 levels between the 2 groups were not statistically significant.

CONCLUSIONS

Hypermethylation of the distal IGR located upstream of ITPR3 is related to greater DCI development in patients with SAH. Further studies of the precise mechanisms of methylation degree and DCI development using in vitro and in vivo models are needed.

MinION rapid sequencing: Review of potential applications in neurosurgery

BACKGROUND

Gene sequencing has played an integral role in the advancement and understanding of disease pathology and treatment. Although historically expensive and time consuming, new sequencing technologies improve our capability to obtain the genetic information in an accurate and timely manner. Within neurosurgery, gene sequencing is routinely used in the diagnosis and treatment of neurosurgical diseases, primarily for brain tumors. This paper reviews nanopore sequencing, an innovation utilized by MinION and outlines its potential use for neurosurgery.

METHODS

A literature search was conducted for publications containing the keywords of Oxford MinION, nanopore sequencing, brain tumor, glioma, whole genome sequencing (WGS), epigenomics, molecular neuropathology, and next-generation sequencing (NGS). In total, 64 articles were selected and used for this review.

RESULTS

The Oxford MinION nanopore sequencing technology has had successful applications within clinical microbiology, human genome sequencing, and cancer genotyping across multiple specialties. Technical details, methodology, and current use of MinION sequencing are discussed through the prism of potential applications to solve neurosurgery-related scientific and diagnostic questions. The MinION device has proven to provide rapid and accurate reads with longer read lengths when compared with NGS. For applications within neurosurgery, the MinION device is capable of providing critical diagnostic information for central nervous system (CNS) tumors within a single day.

CONCLUSIONS

MinION provides rapid and accurate gene sequencing with better affordability and convenience compared with current NGS methods. Widespread success of the MinION nanopore sequencing technology in providing accurate, rapid, and convenient gene sequencing suggests a promising future within research laboratories and to improve care for neurosurgical patients.

The correlation between gene polymorphisms of endothelial nitric oxide synthase and aneurismal subarachnoid hemorrhage

To discuss the association of the T786C and G894T polymorphisms of endothelial nitric oxide synthase (eNOS) with the occurrence and prognosis of aneurismal subarachnoid hemorrhage (aSAH). One hundred sixty-nine patients with aSAH were collected as the case group, which was divided into the good prognosis group and adverse prognosis group according to the condition 3 months after the treatment. One hundred fifty-six healthy volunteers were collected as the control group. The allele and genotype of T786C and G894T polymorphisms of eNOS were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The genotype and allele frequency of eNOS were compared between different groups. And then, the risk factors of aSAH occurrence and prognosis were analyzed by using the logistic regression model. Both the genotype and allele frequency distributions of T786C and G894T between the case group and control group were significantly different (P < 0.05). There were significant differences in the distribution of G894T and T786C allele frequency and G894T genotype between the good prognosis group and adverse prognosis group, and there was no difference in T786C genotype. The results of the logistic regression analysis indicated that T786C and G894T polymorphisms of eNOS were independent influencing factors on the occurrence of aSAH and the G894T polymorphism was also closely related to the prognosis. T786C and G894T polymorphisms of eNOS gene were correlated with the occurrence and prognosis of aSAH, and the G894T polymorphism might be an independent influencing factor.

The role of endothelial nitric oxide synthase -786 T/C polymorphism in cardiac instability following aneurysmal subarachnoid hemorrhage

INTRODUCTION

Cardiac abnormalities are observed frequently after aneurysmal subarachnoid hemorrhage (aSAH). A subset of aSAH patients develops neurogenic cardiomyopathy, likely induced by catecholamine excess. Genetic polymorphisms of the endothelial nitric oxide synthase (eNOS) gene have been linked to decreased nitric oxide (NO) levels, coronary artery spasm, and myocardial infarction. The role of the eNOS single nucleotide polymorphism (SNP) -786 T/C in cardiac instability following aSAH has not been previously investigated.

METHODS

From 2012 to 2015, aSAH patients were prospectively enrolled in the Cerebral Aneurysm Renin Angiotensin System (CARAS) study at two academic institutions. Blood samples were used to assess the eNOS SNP -786 T/C rs2070744 through 5'exonuclease (Taqman) genotyping assays. Associations between this polymorphism and cardiac instability following aSAH were analyzed.

RESULTS

Multivariable analysis demonstrated a dominant effect of the C allele of eNOS SNP -786 T/C on cardiac instability in patients with aSAH. A lower Glasgow Coma Scale score and a history of ischemic vascular disease were also associated with cardiac instability. Furthermore, cardiac instability independently predicted poor functional outcome upon discharge from the hospital.

CONCLUSIONS

The C allele of the eNOS SNP -786 T/C was independently associated with an increased risk for cardiac instability following aSAH. Cardiac instability itself was a risk factor for an unfavorable functional outcome upon discharge from the hospital.

Association of Plasminogen Activator Inhibitor 1 (SERPINE1) Polymorphisms and Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Genetic variations of the serine proteinase inhibitor family E member 1 (SERPINE1) gene, which encodes plasminogen activator inhibitor 1, correlate with serum levels of its product and are associated with thrombophilia and coronary atherosclerosis. Various SERPINE1 ;gene polymorphisms have been identified. However, only the functional 5G/4G polymorphism has been assessed in the context of aneurysmal subarachnoid hemorrhage (aSAH). We assessed associations of 6 SERPINE1 polymorphisms with the clinical sequelae of aSAH.

METHODS

From 2012 to 2015, patients with aSAH were prospectively enrolled into the CARAS (Cerebral Aneurysm Renin Angiotensin System) study at 2 major academic institutions. Blood samples were used to evaluate 6 common SERPINE1 single nucleotide polymorphisms via 5' exonuclease (Taqman) genotyping assays.

RESULTS

There was an association of the AA genotype of rs2227631 with the 4G/4G genotype and of the GG genotype of rs7242 with the AA genotype of rs2227684. In multivariable analysis, patients with the AA genotype of rs2227631 and 4G/4G genotype had an increased risk for developing delayed cerebral ischemia. Patients with the GG genotype of rs7242 and AA genotype of rs2227684 had a decreased risk for a poor functional outcome.

CONCLUSIONS

SERPINE1 gene polymorphisms were associated with delayed cerebral ischemia and functional outcome after aSAH. These associations may arise from alterations of plasminogen activator inhibitor 1 levels.