Clinical Variables and Genetic Risk Factors Associated with the Acute Outcome of Ischemic Stroke: A Systematic Review

Genetics of ischemic stroke functional outcome

Ischemic stroke, which accounts for 87% of cerebrovascular accidents, is responsible for massive global burden both in terms of economic cost and personal hardship. Many stroke survivors face long-term disability-a phenotype associated with an increasing number of genetic variants. While clinical variables such as stroke severity greatly impact recovery, genetic polymorphisms linked to functional outcome may offer physicians a unique opportunity to deliver personalized care based on their patient's genetic makeup, leading to improved outcomes. A comprehensive catalogue of the variants at play is required for such an approach. In this review, we compile and describe the polymorphisms associated with outcome scores such as modified Rankin Scale and Barthel Index. Our search identified 74 known genetic polymorphisms spread across 48 features associated with various poststroke disability metrics. The known variants span diverse biological systems and are related to inflammation, vascular homeostasis, growth factors, metabolism, the p53 regulatory pathway, and mitochondrial variation. Understanding how these variants influence functional outcome may be helpful in maximizing poststroke recovery.

Discovery and validation of molecular patterns and immune characteristics in the peripheral blood of ischemic stroke patients

Background

Stroke is a disease with high morbidity, disability, and mortality. Immune factors play a crucial role in the occurrence of ischemic stroke (IS), but their exact mechanism is not clear. This study aims to identify possible immunological mechanisms by recognizing immune-related biomarkers and evaluating the infiltration pattern of immune cells.

Methods

We downloaded datasets of IS patients from GEO, applied R language to discover differentially expressed genes, and elucidated their biological functions using GO, KEGG analysis, and GSEA analysis. The hub genes were then obtained using two machine learning algorithms (least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE)) and the immune cell infiltration pattern was revealed by CIBERSORT. Gene-drug target networks and mRNA-miRNA-lncRNA regulatory networks were constructed using Cytoscape. Finally, we used RT-qPCR to validate the hub genes and applied logistic regression methods to build diagnostic models validated with ROC curves.

Results

We screened 188 differentially expressed genes whose functional analysis was enriched to multiple immune-related pathways. Six hub genes (ANTXR2, BAZ2B, C5AR1, PDK4, PPIH, and STK3) were identified using LASSO and SVM-RFE. ANTXR2, BAZ2B, C5AR1, PDK4, and STK3 were positively correlated with neutrophils and gamma delta T cells, and negatively correlated with T follicular helper cells and CD8, while PPIH showed the exact opposite trend. Immune infiltration indicated increased activity of monocytes, macrophages M0, neutrophils, and mast cells, and decreased infiltration of T follicular helper cells and CD8 in the IS group. The ceRNA network consisted of 306 miRNA-mRNA interacting pairs and 285 miRNA-lncRNA interacting pairs. RT-qPCR results indicated that the expression levels of BAZ2B, C5AR1, PDK4, and STK3 were significantly increased in patients with IS. Finally, we developed a diagnostic model based on these four genes. The AUC value of the model was verified to be 0.999 in the training set and 0.940 in the validation set.

Conclusion

Our research explored the immune-related gene expression modules and provided a specific basis for further study of immunomodulatory therapy of IS.

Effect of abnormal body weight on mortality and functional recovery in adults after stroke: An umbrella review

BACKGROUND

Several published systematic reviews have drawn conflicting conclusions on the effect of abnormal body weight (i.e. being underweight, overweight or obese) on outcomes following stroke. The 'obesity paradox' seen in several diseases (wherein obesity, often associated with mortality and morbidity, appears to be protective and improve outcomes) may be evident after stroke, but inconsistent results of existing reviews, and the issue of being underweight, are worth investigating further.

AIMS

To better understand the impact of body weight on prognosis after stroke, we aimed to answer the following research question: What is the effect of abnormal body weight (underweight, overweight, or obesity) on mortality and functional recovery in adults after stroke?

SUMMARY OF REVIEW

We conducted an umbrella review to synthesize existing evidence on the effects of abnormal body weight on stroke outcomes. We searched Cumulated Index to Nursing and Allied Health Literature (CINAHL) Complete, COCHRANE Database of Systematic Reviews, PubMed, Medline, PEDro, and EMBASE Classic + EMBASE, from inception until 28 February 2023. Seven systematic reviews (1,136,929 participants) from 184 primary studies (counting duplicates) were included. While the risk of mortality increases with being underweight (body mass index (BMI) < 18.5 kg/m2), excess body weight (being overweight (BMI = 25-29.9 kg/m2) or obese (BMI > 30 kg/m2)) is associated with reduced mortality. The impact of abnormal body weight on functional recovery is less clear; data from studies of being underweight are associated with poor functional outcomes while those from studies of excess body weight are inconclusive.

CONCLUSION

Abnormal body weight effects post-stroke outcomes and should be considered in clinical decision-making, prognostic research, and clinical trials of rehabilitation interventions. The "obesity paradox" is evident after stroke, and excess body weight is associated with reduced mortality compared to normal body weight. It is recommended that body weight is routinely recorded for stroke patients, and further research, including well-designed cohort studies with reliable weight data, is needed to further investigate the impact of body weight and distribution on post-stroke outcomes.

Explaining predictors of discharge destination assessed along the patients' acute stroke journey

INTRODUCTION

Accurate prediction of outcome destination at an early stage would help manage patients presenting with stroke. This study assessed the predictive ability of three machine learning (ML) algorithms to predict outcomes at four different stages as well as compared the predictive power of stroke scores.

METHODS

Patients presenting with acute stroke to the Canberra Hospital between 2015 and 2019 were selected retrospectively. 16 potential predictors and one target variable (discharge destination) were obtained from the notes. k-Nearest Neighbour (kNN) and two ensemble-based classification algorithms (Adaptive Boosting and Bootstrap Aggregation) were employed to predict outcomes. Predictive accuracy was assessed at each of the four stages using both overall and per-class accuracy. The contribution of each variable to the prediction outcome was evaluated by the ensemble-based algorithm and using the Relief feature selection algorithm. Various combinations of stroke scores were tested using the aforementioned models.

RESULTS

Of the three ML models, Adaptive Boosting demonstrated the highest accuracy (90%) at Stage 4 in predicting death while the highest overall accuracy (81.7%) was achieved by kNN (k=2/City-block distance). Feature importance analysis has shown that the most important features are the 24-hour Scandinavian Stroke Scale (SSS) and 24-hour National Institutes of Health Stroke Scale (NIHSS) scores, dyslipidaemia, hypertension and premorbid mRS score. For the initial and 24-hour scores, there was a higher correlation (0.93) between SSS scores than for NIHSS scores (0.81). Reducing the overall four scores to InitSSS/24hrNIHSS increased accuracy to 95% in predicting death (Adaptive Boosting) and overall accuracy to 85.4% (kNN). Accuracies at Stage 2 (pre-treatment, 11 predictors) were not far behind those at Stage 4.

CONCLUSION

Our findings suggest that even in the early stages of management, a clinically useful prediction regarding discharge destination can be made. Adaptive Boosting might be the best ML model, especially when it comes to predicting death. The predictors' importance analysis also showed that dyslipidemia and hypertension contributed to the discharge outcome even more than expected. Further, surprisingly using mixed score systems might also lead to higher prediction accuracies.

Association between Genetic Polymorphism of The lncRNA MIAT rs1894720 with Ischemic Stroke Risk and lncRNA MIAT Expression Levels in The Blood after An Ischemic Stroke: A Case-Control Study

OBJECTIVE

Genetic aspects can play an essential role in the occurrence and development of ischemic stroke (IS). Rs1894720 polymorphism is one of the eight single nucleotide polymorphisms (SNPs) in the long non-coding RNA (lncRNA) myocardial infarction-associated transcript (MIAT) locus. The aim of study is the lncRNA MIAT rs1894720 polymorphism decreases IS risk by reducing lncRNA MIAT expression.

MATERIALS AND METHODS

In this case-control study, we studied 232 Iranian patients and 232 controls. The blood samples were collected from patients admitted at different times after stroke symptoms. We enrolled 80, 78, and 74 patients who arrived at the hospital between 0-24, 24-48, and 48-72 hours after the first appearance of symptoms, respectively. DNA genotyping was done by the tetra-primer ARMS-PCR method. Circulating MIAT levels were evaluated by real-time polymerase chain reaction (PCR).

RESULTS

The GT genotype of MIAT rs1894720 showed a significant association with the risk of IS (OR=3.53, 95% CI=2.13-5.84, P<0.001). MIAT expression was higher relative to the control within the first hours after IS. The MIAT levels in IS patients with rs1894720 (GT) were significantly lower relative to patients who had the GG and TT genotypes. Linear regression model indicated a significant correlation between MIAT expression with atherosclerotic risk factors and types of stroke in IS patients. Receiver operating characteristic (ROC) curve analysis showed that the level of lncRNA MIAT after IS could be diagnostic with an area under the curve (AUC) of 0.82. The sensitivity and specificity were 80.17 and 67.24%, respectively (P<0.001).

CONCLUSION

Our study demonstrated that the MIAT rs1894720 polymorphism (GT) might increase the risk of IS in the Iranian population. MIAT expression was up-regulated in our IS patients. Hence, it could be a diagnostic biomarker for IS.

Predictors of Early Neurological Improvement and Its Relationship to Thrombolysis Treatment and Long-Term Outcome in the WAKE-UP Study

INTRODUCTION

The aims of this study were to evaluate the relationship of clinical and imaging baseline factors and treatment on the occurrence of early neurological improvement (ENI) in the WAKE-UP trial of MRI-guided intravenous thrombolysis in unknown onset stroke and to examine the association of ENI with long-term favorable outcome in patients treated with intravenous thrombolysis.

METHODS

We analyzed data from all patients with at least moderate stroke severity, reflected by an initial National Institutes of Health Stroke Scale (NIHSS) score ≥4 randomized in the WAKE-UP trial. ENI was defined as a decrease in NIHSS of ≥8 or a decline to zero or 1 at 24 h after initial presentation to the hospital. Favorable outcome was defined as a modified Rankin Scale score of 0-1 at 90 days. We performed group comparison and multivariable analysis of baseline factors associated with ENI and performed mediation analysis to evaluate the effect of ENI on the relationship between intravenous thrombolysis and favorable outcome.

RESULTS

ENI occurred in 93 out of 384 patients (24.2%) and was more likely to occur in patients who received treatment with alteplase (62.4% vs. 46.0%, p = 0.009), had smaller acute diffusion-weighted imaging lesion volume (5.51 mL vs. 10.9 mL, p ≤ 0.001), and less often large-vessel occlusion on initial MRI (7/93 [12.1%] versus 40/291 [29.9%], p = 0.014). In multivariable analysis, treatment with alteplase (OR 1.97, 95% confidence interval [CI] 0.954-1.100), lower baseline stroke volume (OR 0.965, 95% CI: 0.932-0.994), and shorter time from symptom recognition to treatment (OR 0.994, 95% CI: 0.989-0.999) were independently associated with ENI. Patients with ENI had higher rates of favorable outcome at 90-day follow-up (80.6% vs. 31.3%, p ≤ 0.001). The occurrence of ENI significantly mediated the association of treatment with a good outcome, with ENI at 24 h explaining 39.4% (12.9-96%) of the treatment effect.

CONCLUSION

Intravenous alteplase increases the odds of ENI in patients with at least moderate stroke severity, especially when given early. In patients with large-vessel occlusion, ENI is rarely observed without thrombectomy. ENI represents a good surrogate early marker of treatment effect as more than a third of good outcome at 90 days is explained by ENI at 24 h.

Soluble ST2 Predicts Poor Functional Outcome in Acute Ischemic Stroke Patients

INTRODUCTION

There are very limited data on the role of biomarkers correlating with the outcome in acute ischemic stroke (AIS). We evaluated the predictive values of the plasma concentrations of soluble serum stimulation-2 (sST2), matrix metalloproteinase-9 (MMP-9), and claudin-5 in AIS.

METHODS

The biomarker levels in the plasma samples of consecutive AIS patients collected at baseline, 12 h, and 24 h from stroke onset were quantified using immunoassays. Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) and functional outcome at 90 days using the modified Rankin Scale (mRS), with scores above 3 defined as poor outcome. Receiver operating characteristic curve analysis and multiple logistic regression were performed for evaluating the discriminative power of each marker.

RESULTS

We included 108 patients in the study (mean age 62.3 ± 11.7 years). Median NIHSS score was 12 (interquartile range 8-18). High baseline glucose levels, systolic blood pressure, baseline NIHSS, low Alberta Stroke Program Early CT Score, and hemorrhagic transformation were associated with poor outcomes. Elevated sST2 at 12 h (50.4 ± 51.0 ng/mL; p = 0.047) and 24 h (81.8 ± 101.3 ng/mL; p = 0.001) positively correlated with poor outcomes. MMP-9 (p = 0.086) and claudin-5 (p = 0.2) were not significantly associated with the outcome, although increased expressions of both markers were observed at 12 h. Multiple logistic regression showed that sST2 levels ≥71.8 ng/mL at 24 h, with a specificity of 96.9%, emerged as an independent predictor of poor functional outcome (OR: 6.44; 95% CI: 1.40-46.3; p = 0.029).

CONCLUSION

Evaluation of sST2 may act as a reliable biomarker of functional outcome in AIS.

Early peripheral blood gene expression associated with good and poor 90-day ischemic stroke outcomes

BACKGROUND

This study identified early immune gene responses in peripheral blood associated with 90-day ischemic stroke (IS) outcomes.

METHODS

Peripheral blood samples from the CLEAR trial IS patients at ≤ 3 h, 5 h, and 24 h after stroke were compared to vascular risk factor matched controls. Whole-transcriptome analyses identified genes and networks associated with 90-day IS outcome assessed using the modified Rankin Scale (mRS) and the NIH Stroke Scale (NIHSS).

RESULTS

The expression of 467, 526, and 571 genes measured at ≤ 3, 5 and 24 h after IS, respectively, were associated with poor 90-day mRS outcome (mRS ≥ 3), while 49, 100 and 35 genes at ≤ 3, 5 and 24 h after IS were associated with good mRS 90-day outcome (mRS ≤ 2). Poor outcomes were associated with up-regulated genes or pathways such as IL-6, IL-7, IL-1, STAT3, S100A12, acute phase response, P38/MAPK, FGF, TGFA, MMP9, NF-kB, Toll-like receptor, iNOS, and PI3K/AKT. There were 94 probe sets shared for poor outcomes vs. controls at all three time-points that correlated with 90-day mRS; 13 probe sets were shared for good outcomes vs. controls at all three time-points; and 46 probe sets were shared for poor vs. good outcomes at all three time-points that correlated with 90-day mRS. Weighted Gene Co-Expression Network Analysis (WGCNA) revealed modules significantly associated with 90-day outcome for mRS and NIHSS. Poor outcome modules were enriched with up-regulated neutrophil genes and with down-regulated T cell, B cell and monocyte-specific genes; and good outcome modules were associated with erythroblasts and megakaryocytes. Finally, genes identified by genome-wide association studies (GWAS) to contain significant stroke risk loci or loci associated with stroke outcome including ATP2B, GRK5, SH3PXD2A, CENPQ, HOXC4, HDAC9, BNC2, PTPN11, PIK3CG, CDK6, and PDE4DIP were significantly differentially expressed as a function of stroke outcome in the current study.

CONCLUSIONS

This study suggests the immune response after stroke may impact functional outcomes and that some of the early post-stroke gene expression markers associated with outcome could be useful for predicting outcomes and could be targets for improving outcomes.

Polymorphonuclear phenotypical expression of CD18, at baseline and after in vitro activation, in several clinical disorders: Revision of our case series

BACKGROUND

In relation to the different and important roles of the beta2 integrins, we have revisited the expression of polymorphonuclear leukocyte CD18 in several clinical disorders, at baseline and after in vitro activation.

SUBJECTS

we have examined subjects with type 1 diabetes mellitus, vascular atherosclerotic disease, type 2 diabetes mellitus without and with macrovascular complications, chronic renal failure on conservative treatment, essential hypertension, deep venous thrombosis, acute ischemic stroke and subjects with venous leg ulcers.

METHODS

unfractioned leukocyte suspension was prepared according to the Mikita's method, while the leukocyte were separated into mononuclear and polymorphonuclear cells with a Ficoll-Hypaque medium. Using specific monoclonal antibody, the CD18 expression was evaluated with cytofluorimetric analysis, using FACScan (Becton Dickinson) be Cellquest software; the activation in vitro with PMA was effected according to modified Yasui and Masuda methods.

RESULTS

in type 1 diabetes mellitus, at baseline CD18 is under expressed in comparison with normal control, and not changes after PMA activation were observed; in subjects with vascular atherosclerotic disease, in type 2 diabetes mellitus CD18 is over expressed at baseline but does not vary after activation; in subjects with chronic renal failure, essential hypertension and in subjects with acute ischemic stroke the CD18 up-regulate at baseline compared to normal control, and it increases further after activation; in subjects with deep venous thrombosis the CD18 expression is not different from control group at baseline, but it increases after activation; finally, in subjects with venous leg ulcers the CD18 is normally expressed at baseline, and it does not change after PMA activation.

CONCLUSIONS

in the different clinical disorders, the trend of this integrin subunit provides some specific information, useful to select the best therapeutic strategy in clinical practice.

Fasting blood glucose as a predictor of progressive infarction in men with acute ischemic stroke

Objective

Blood glucose is related to early neurological deterioration in acute ischemic stroke, but multiple mechanisms are involved in early neurological deterioration, such as progressive infarction. This study aimed to determine whether fasting blood glucose (FBG) is an independent predictor of progressive infarction.

Methods

From April 2017 to December 2020, we retrospectively enrolled 477 patients with acute ischemic stroke within 48 hours of onset. Demographic characteristics, clinical information, neuroimaging characteristics, and laboratory data were collected after admission.

Results

We found that 147 (30.8%) patients had progressive infarction. Multiple regression analysis showed that high FBG concentrations (>7.66 mmol/L) were independently associated with progressive infarction. Sex subgroup analysis showed that high FBG concentrations were an independent predictor of progressive infarction in male patients (odds ratio, 2.559; 95% confidence interval, 1.279–5.121). In a receiver operating characteristic curve analysis, FBG concentrations were a predictor of progressive infarction in all cases, especially in male patients. The cutoff value of FBG in all patients and men was 7.155 mmol/L.

Conclusions

FBG is an independent predictor of progressive infarction in patients with acute ischemic stroke within 48 hours of onset, especially in men. Patients with FBG concentrations ≥7.155 mmol/L are more likely to develop progressive infarction.

A tree-based gene-environment interaction analysis with rare features

Gene-environment (G-E) interaction analysis plays a critical role in understanding and modeling complex diseases. Compared to main-effect-only analysis, it is more seriously challenged by higher dimensionality, weaker signals, and the unique "main effects, interactions" variable selection hierarchy. In joint G-E interaction analysis under which a large number of G factors are analysed in a single model, effort tailored to rare features (e.g., SNPs with low minor allele frequencies) has been limited. Existing investigations on rare features have been mostly focused on marginal analysis, where various data aggregation techniques have been developed, and hypothesis testings have been conducted to identify significant aggregated features. However, such techniques cannot be extended to joint G-E interaction analysis. In this study, building on a very recent tree-based data aggregation technique, which has been developed for main-effect-only analysis, we develop a new G-E interaction analysis approach tailored to rare features. The adopted data aggregation technique allows for more efficient information borrowing from neighboring rare features. Similar to some existing state-of-the-art ones, the proposed approach adopts penalization for variable selection, regularized estimation, and respect of the variable selection hierarchy. Simulation shows that it has more accurate identification of important interactions and main effects than several competing alternatives. In the analysis of NFBC1966 study, the proposed approach leads to findings different from the alternatives and with satisfactory prediction and stability performance.

Altered methylation pattern in EXOC4 is associated with stroke outcome: an epigenome-wide association study

BACKGROUND AND PURPOSE

The neurological course after stroke is highly variable and is determined by demographic, clinical and genetic factors. However, other heritable factors such as epigenetic DNA methylation could play a role in neurological changes after stroke.

METHODS

We performed a three-stage epigenome-wide association study to evaluate DNA methylation associated with the difference between the National Institutes of Health Stroke Scale (NIHSS) at baseline and at discharge (ΔNIHSS) in ischaemic stroke patients. DNA methylation data in the Discovery (n = 643) and Replication (n = 62) Cohorts were interrogated with the 450 K and EPIC BeadChip. Nominal CpG sites from the Discovery (p value < 10-06) were also evaluated in a meta-analysis of the Discovery and Replication cohorts, using a random-fixed effect model. Metabolic pathway enrichment was calculated with methylGSA. We integrated the methylation data with 1305 plasma protein expression levels measured by SOMAscan in 46 subjects and measured RNA expression with RT-PCR in a subgroup of 13 subjects. Specific cell-type methylation was assessed using EpiDISH.

RESULTS

The meta-analysis revealed an epigenome-wide significant association in EXOC4 (p value = 8.4 × 10-08) and in MERTK (p value = 1.56 × 10-07). Only the methylation in EXOC4 was also associated in the Discovery and in the Replication Cohorts (p value = 1.14 × 10-06 and p value = 1.3 × 10-02, respectively). EXOC4 methylation negatively correlated with the long-term outcome (coefficient = - 4.91) and showed a tendency towards a decrease in EXOC4 expression (rho = - 0.469, p value = 0.091). Pathway enrichment from the meta-analysis revealed significant associations related to the endocytosis and deubiquitination processes. Seventy-nine plasma proteins were differentially expressed in association with EXOC4 methylation. Pathway analysis of these proteins showed an enrichment in natural killer (NK) cell activation. The cell-type methylation analysis in blood also revealed a differential methylation in NK cells.

CONCLUSIONS

DNA methylation of EXOC4 is associated with a worse neurological course after stroke. The results indicate a potential modulation of pathways involving endocytosis and NK cells regulation.

Genome-Wide Studies in Ischaemic Stroke: Are Genetics Only Useful for Finding Genes?

Ischaemic stroke is a complex disease with some degree of heritability. This means that heritability factors, such as genetics, could be risk factors for ischaemic stroke. The era of genome-wide studies has revealed some of these heritable risk factors, although the data generated by these studies may also be useful in other disciplines. Analysis of these data can be used to understand the biological mechanisms associated with stroke risk and stroke outcome, to determine the causality between stroke and other diseases without the need for expensive clinical trials, or to find potential drug targets with higher success rates than other strategies. In this review we will discuss several of the most relevant studies regarding the genetics of ischaemic stroke and the potential use of the data generated.

Factors Associated with Unfavorable Functional Outcomes After Intravenous Thrombolysis in Patients with Acute Ischemic Stroke

Purpose

Intravenous thrombolysis (IVT) has become a standard treatment for eligible ischemic stroke patients. However, functional outcomes after receiving IVT varied widely. Hence the primary goal of this study is to identify characteristics related to poor outcomes.

Patients and Methods

The study enrolled acute ischemic stroke patients aged 18 or older who received IVT within 4.5 hours after onset between January 2018 and December 2020. The data were retrospectively collected from medical records. The patients were classified as having an excellent (0–2) or poor (3–6) outcomes based on the 90-day modified Rankin Scale (mRS). Univariable and multivariable logistic regression analyses were used to evaluate the results. The predictive model was determined and developed the score using regression coefficients. The prediction power was validated using the area under the receiver operating characteristic curve analysis.

Results

The study included 138 eligible participants. Forty-eight patients had unfavorable functional outcomes. With multivariable logistic regression analysis, factors significantly associated with poor outcomes were age (adjusted odds ratio (AOR), 1.03; 95% confidence interval (CI), 0.99–1.07; P = 0.05), diabetes (3.96; 1.61–9.37; P = 0.003), admission National Institute of Health Stroke Scale (NIHSS) (1.08; 1.01–1.15; P = 0.02) and initial Alberta Stroke Program Early Computed Tomography Score (ASPECTS) (0.56; 0.37–0.86; P = 0.009). The predictive model developed from the findings demonstrated good discrimination power (AuROC 0.803, 95% CI 0.728–0.877).

Conclusion

The current study found that older age, diabetes, atrial fibrillation, higher admission NIHSS, and lower ASPECTS on the initial NCCT brain were related to unfavorable functional outcomes following IVT and served as good predictors of patient functional outcomes.

Stroke Genomics: Current Knowledge, Clinical Applications and Future Possibilities

The pathophysiology of stoke involves many complex pathways and risk factors. Though there are several ongoing studies on stroke, treatment options are limited, and the prevalence of stroke is continuing to increase. Understanding the genomic variants and biological pathways associated with stroke could offer novel therapeutic alternatives in terms of drug targets and receptor modulations for newer treatment methods. It is challenging to identify individual causative mutations in a single gene because many alleles are responsible for minor effects. Therefore, multiple factorial analyses using single nucleotide polymorphisms (SNPs) could be used to gain new insight by identifying potential genetic risk factors. There are many studies, such as Genome-Wide Association Studies (GWAS) and Phenome-Wide Association Studies (PheWAS) which have identified numerous independent loci associated with stroke, which could be instrumental in developing newer drug targets and novel therapies. Additionally, using analytical techniques, such as meta-analysis and Mendelian randomization could help in evaluating stroke risk factors and determining treatment priorities. Combining SNPs into polygenic risk scores and lifestyle risk factors could detect stroke risk at a very young age and help in administering preventive interventions.

Q-15 Minutes Vital Sign Documentation Is a Poor Surrogate for Assessing Quality of Care After Acute Ischemic Stroke

OBJECTIVE

Documenting vital signs and National Institutes of Health Stroke Scale (NIHSS) once every 15 minutes after intravenous thrombolytic therapy for acute ischemic stroke is often used as a metric to assess the quality of care. This study explores the association between "once every 15 minutes" documentation and stroke outcomes.

METHODS

This is a retrospective study of the first 2 hours of vital signs and NIHSS documentation after thrombolytic stroke therapy. Sociodemographic and clinical data, including NIHSS, temperature, heart rate, systolic blood pressure, diastolic blood pressure, mean arterial blood pressure, and respiratory rate, were abstracted from the medical record. Missing documentation was examined for association with modified Rankin Scale (mRS) scores and neurologic changes.

RESULT

Among 84 patients with a mean age of 68.8 years, there were 2276 documented assessments from an expected 3780. There were 104 clinically significant changes in 1 or more index variables. The most commonly missed documentation occurred during interventional radiology. After controlling for admission NIHSS, there was no significant relationship between the completeness of documentation and discharge mRS score (r2 = 0.047, P = .0561), nor between vital sign documentation and discharge mRS (r2 = 0.003, P = .6338).

CONCLUSION

Frequency of documentation does not reflect the quality of care during the early phase of acute stroke treatment.

Low vitamin D levels and the long-term functional outcome of stroke up to 5 years

BACKGROUND AND PURPOSE

Previous studies have established that vitamin D was associated with stroke. The purpose of this study was to investigate the relationship between vitamin D and 5-year outcome of patients with stroke including acute ischemic stroke (AIS) and intracranial hemorrhage (ICH) stroke.

METHODS

Serum 25-hydroxyvitamin D levels were prospectively analyzed in patients admitted to the First Affiliated Hospital of Wenzhou Medical University from 2013 to 2015. Modified Rankin scale (mRS) was used to evaluate their 5-year functional outcome, and univariate and multivariate logistic regressions were applied to evaluate the effects of vitamin D on stroke outcome.

RESULTS

In total, 668 patients diagnosed with stroke were recruited, and 420 completed the 5-year follow-up. Ninety-five patients experienced poor outcome in the 5 years since stroke onset. Vitamin D levels in patients with poor outcome showed significant differences compared to good outcome patients (p < .001). In multivariable logistic regression analysis, after adjusting the potential confounders, the 5-year functional outcome was significantly associated with vitamin D levels. Stroke patients with vitamin D levels less than 38.4 nmol/L had a higher risk for poor outcome compared with those with vitamin D level over 71.4 nmol/L at 5-year (odds ratio [OR] = 3.66, 95% confidence interval [CI] = 1.42-9.45, p = .007), which was consistent with AIS patients (OR = 6.36, 95% CI = 1.89-21.44, p = .003).

CONCLUSION

Vitamin D level less than 38.4 nmol/L at admission is a potential risk biomarker for poor functional outcome at 5-year prognosis in AIS patients, which might provide new ideas for the prognostic assessment of stroke.

Using Human Genetics to Understand Mechanisms in Ischemic Stroke Outcome: From Early Brain Injury to Long-Term Recovery

There is a critical need to elucidate molecular mechanisms underlying brain injury, repair, and recovery following ischemic stroke-a global health problem with major social and economic impact. Despite 5 decades of intensive research, there are no widely accepted neuroprotective drugs that mitigate ischemic brain injury, or neuroreparative drugs, or personalized approaches that guide therapies to enhance recovery. We here explore novel reverse translational approaches that will complement traditional forward translational methods in identifying mechanisms relevant to human stroke outcome. Although genome-wide association studies have yielded over 30 genetic loci that influence ischemic stroke risk, only a few genome-wide association studies have been performed for stroke outcome. We discuss important considerations for genetic studies of ischemic stroke outcome-including carefully designed phenotypes that capture injury/recovery mechanisms, anchored in time to stroke onset. We also address recent genome-wide association studies that provide insight into mechanisms underlying brain injury and repair. There are several ongoing initiatives exploring genomic associations with novel phenotypes related to stroke outcome. To improve the understanding of the genetic architecture of ischemic stroke outcome, larger studies using standardized phenotypes, preferably embedded in standard-of-care measures, are needed. Novel techniques beyond genome-wide association studies-including exploiting informatics, multi-omics, and novel analytics-promise to uncover genetic and molecular pathways from which drug targets and other new interventions may be identified.

Admission Hydration Status and Ischemic Stroke Outcome-Experience from a National Registry of Hospitalized Stroke Patients

Reduced intravascular volume upon ischemic stroke (IS) admission has been associated with in-hospital complications, disability, and reduced survival. We aimed to evaluate the association of the urea-to-creatinine ratio (UCR) with disability or death at discharge, length of stay, in-hospital complications, and mortality during the first year. Using a national registry, we identified hospitalized IS patients without renal failure. Disability or death at discharge, length of stay, in-hospital complications, and mortality during the first year were studied by UCR, and associations between UCR levels and each outcome were assessed adjusting for age, sex, stroke severity, comorbidities, use of statins, and use of diuretics. In total, 2212 patients were included. Levels (median (25–75%)) for the main study variables were: urea 5.16 (3.66–6.83) mmol/L; creatinine 80 (64–92) µmol/L; and UCR 65 (58–74). Levels of UCR were significantly higher in patients with disability or death at discharge (p < 0.0001), those with complications during hospitalization (p = 0.03), those with infection during hospitalization (p = 0.0003), and those dead at 1 year (p < 0.0001). Analysis by UCR quartile showed that rates of disability or death at discharge, infections, complications overall, and death at 1 year in patients with UCR in the 4th quartile were significantly higher than in others. Risk-factor-adjusted analysis by UCR quartiles demonstrated an inconsistent independent association between UCR and disability or death after ischemic stroke. A high 1-year mortality rate was observed in IS patients with elevated UCR, yet this finding was not statistically significant after controlling for risk factors. Our study shows inconsistent associations between hydration status and poor functional status at discharge, and no association with length of stay, in-hospital complications (infectious and overall), and 1-year mortality.

The association between telomere length and ischemic stroke risk and phenotype

The chronological age of a person is a key determinant of etiology and prognosis in the setting of ischemic stroke. Telomere length, an indicator of biological aging, progressively shortens with every cell cycle. Herein, we determined telomere length from peripheral blood leukocytes by Southern blot analyses in a prospective cohort of ischemic stroke patients (n = 163) and equal number of non-stroke controls and evaluated its association with various ischemic stroke features including etiology, severity, and outcome. A shorter telomere length (i.e. lowest quartile; ≤ 5.5 kb) was significantly associated with ischemic stroke (OR 2.95, 95% CI 1.70–5.13). This significant relationship persisted for all stroke etiologies, except for other rare causes of stroke. No significant association was present between admission lesion volume and telomere length; however, patients with shorter telomeres had higher admission National Institutes of Health Stroke Scale scores when adjusted for chronological age, risk factors, etiology, and infarct volume (p = 0.046). On the other hand, chronological age, but not telomere length, was associated with unfavorable outcome (modified Rankin scale > 2) and mortality at 90 days follow-up. The association between shorter telomere length and more severe clinical phenotype at the time of admission, might reflect reduced resilience of cerebral tissue to ischemia as part of biological aging.

International stroke genetics consortium recommendations for studies of genetics of stroke outcome and recovery

Numerous biological mechanisms contribute to outcome after stroke, including brain injury, inflammation, and repair mechanisms. Clinical genetic studies have the potential to discover biological mechanisms affecting stroke recovery in humans and identify intervention targets. Large sample sizes are needed to detect commonly occurring genetic variations related to stroke brain injury and recovery. However, this usually requires combining data from multiple studies where consistent terminology, methodology, and data collection timelines are essential. Our group of expert stroke and rehabilitation clinicians and researchers with knowledge in genetics of stroke recovery here present recommendations for harmonizing phenotype data with focus on measures suitable for multicenter genetic studies of ischemic stroke brain injury and recovery. Our recommendations have been endorsed by the International Stroke Genetics Consortium.

A Workflow for Selection of Single Nucleotide Polymorphic Markers for Studying of Genetics of Ischemic Stroke Outcomes

In this paper we propose a workflow for studying the genetic architecture of ischemic stroke outcomes. It develops further the candidate gene approach. The workflow is based on the animal model of brain ischemia, comparative genomics, human genomic variations, and algorithms of selection of tagging single nucleotide polymorphisms (tagSNPs) in genes which expression was changed after ischemic stroke. The workflow starts from a set of rat genes that changed their expression in response to brain ischemia and results in a set of tagSNPs, which represent other SNPs in the human genes analyzed and influenced on their expression as well.

Admission Glucose Levels May Increase the Risk for Early Neurological Deterioration in Females With Acute Ischemic Stroke

Background and purpose: Early neurological deterioration (END) is associated with poor outcome for patients with acute ischemic stroke (AIS). Patients with hyperglycemia have increased risk for stroke and tend to have poor outcome with and without diabetes after stroke. The present study aimed to determine if blood glucose was associated with END and if sex difference was present in the development of END in AIS patients.

Methods: A total of 220 consecutive patients (both males and females) with AIS between 2012 and 2015 were screened for this retrospective study. After exclusion, 213 patients were included for analysis. Propensity-score matching was used for normalization of variables including stroke severity, time from symptom onset to treatment, and treatment methods.

Results: END was present in 68 patients (31.9%). Multivariate regression analysis showed that the risk of END was significantly higher in males with AIS than in females (P < 0.001), and admission blood glucose level was independently associated with END (P < 0.001). However, subgroup analysis demonstrated that admission glucose levels were significantly associated with increased risk for END only in females, but not in males (P = 0.008). When the cutoff value of 107.1 mg/dL was used, the admission blood glucose level had a significant predictive value for END prediction with a sensitivity of 100% and a specificity of 53% in female patients.

Conclusions: The data demonstrated that sex difference was present for the development of END in AIS patients with an increased risk for males. The present study also showed that admission glucose level could be an important predicting factor for END in female patients with AIS.

Genetic Aspects of Inflammation and Immune Response in Stroke

Genetic determinants play important role in the complex processes of inflammation and immune response in stroke and could be studied in different ways. Inflammation and immunomodulation are associated with repair processes in ischemic stroke, and together with the concept of preconditioning are promising modes of stroke treatment. One of the important aspects to be considered in the recovery of patients after the stroke is a genetic predisposition, which has been studied extensively. Polymorphisms in a number of candidate genes, such as IL-6, BDNF, COX2, CYPC19, and GPIIIa could be associated with stroke outcome and recovery. Recent GWAS studies pointed to the variant in genesPATJ and LOC as new genetic markers of long term outcome. Epigenetic regulation of immune response in stroke is also important, with mechanisms of histone modifications, DNA methylation, and activity of non-coding RNAs. These complex processes are changing from acute phase over the repair to establishing homeostasis or to provoke exaggerated reaction and death. Pharmacogenetics and pharmacogenomics of stroke cures might also be evaluated in the context of immuno-inflammation and brain plasticity. Potential novel genetic treatment modalities are challenged but still in the early phase of the investigation.

Better oral hygiene is associated with lower risk of stroke

BACKGROUND

Periodontal disease or poor oral hygiene may lead to local infection, inflammation, and systemic inflammatory reactions, which are important mediators of development of stroke. We aimed to investigate the association of oral hygiene with risk of stroke in a nationwide population-based cohort.

METHODS

From Korean National Health Insurance System-Health Screening Cohort, 206,602 participants without missing data regarding demographic information, medical history, or blood/urine examination results were included. The presence of periodontal disease and indicators of oral hygiene, such as number of tooth brushings, dental visit history, dental scaling, and number of teeth loss and dental caries were evaluated. Occurrence of stroke including cerebral infarction, cerebral hemorrhage, and subarachnoid hemorrhage was defined as newly registration of International Classification of Diseases-10 codes from I60 to I64 accompanying brain CT and/or MR examination at that time of diagnosis.

RESULTS

The 7337 (3.6%) cases of stroke including 5795 (79.0%) cases of cerebral infarction, 1568 (21.4%) cases of cerebral hemorrhage, and 621 (8.5%) cases of subarachnoid hemorrhage occurred during a median 10.4 years follow-up. In multivariable analysis, frequent tooth brushing (≥3 times per day) was negatively associated with risk of stroke occurrence (hazard ratio [HR]: 0.78, 95% confidence interval [CI]: 0.73-0.84). Number of dental caries (≥4) was positively related to stroke occurrence (HR: 1.28, 95% CI: 1.13-1.44).

CONCLUSIONS

Regular oral hygiene behavior was negatively, and infrequent oral hygiene care was positively associated with risk of occurrence for stroke, respectively. Brushing one's teeth three or more times daily may be associated with lower risk of stroke.