Fluorescent molecular peroxidation products: a prognostic biomarker of early neurologic deterioration after thrombolysis

Blood-Based Biomarkers: A Forgotten Friend of Hyperacute Ischemic Stroke

Ischemic stroke (IS) is the second leading cause of death worldwide. Multimodal neuroimaging techniques that have significantly facilitated the diagnosis of hyperacute IS are not widely used in underdeveloped areas and community hospitals owing to drawbacks such as high cost and lack of trained operators. Moreover, these methods do not have sufficient resolution to detect changes in the brain at the cellular and molecular levels after IS onset. In contrast, blood-based biomarkers can reflect molecular and biochemical alterations in both normal and pathophysiologic processes including angiogenesis, metabolism, inflammation, oxidative stress, coagulation, thrombosis, glial activation, and neuronal and vascular injury, and can thus provide information complementary to findings from routine examinations and neuroimaging that is useful for diagnosis. In this review, we summarize the current state of knowledge on blood-based biomarkers of hyperacute IS including those associated with neuronal injury, glial activation, inflammation and oxidative stress, vascular injury and angiogenesis, coagulation and thrombosis, and metabolism as well as genetic and genomic biomarkers. Meanwhile, the blood sampling time of the biomarkers which are cited and summarized in the review is within 6 h after the onset of IS. Additionally, we also discuss the diagnostic and prognostic value of blood-based biomarkers in stroke patients, and future directions for their clinical application and development.

Blood Biomarkers of Parenchymal Damage in Ischemic Stroke Patients Treated With Revascularization Therapies

Purpose

Postischemic reperfusion injury may exacerbate cerebral damage and capillary dysfunction, leading to brain edema (BE), hemorrhagic transformation (HT), necrosis, and injury from free radicals with subsequent infarct growth (IG). Several plasmatic biomarkers involved in the ischemic cascade have been studied in relation to radiological and clinical outcomes of reperfusion injury in ischemic stroke with heterogeneous results. This article provides a brief overview of the contribution of circulating biomarkers to the pathophysiology of parenchymal damage in ischemic stroke patients treated with revascularization therapies.

Methods

We included full reports with measurements of plasma markers in patients with acute ischemic stroke treated with revascularization therapies.

Findings

Our research included a large number of observational studies investigating a possible role of circulating biomarkers in the development of parenchymal damage after acute stroke treatments. To make the results clearer, we divided the review in 4 sections, exploring the relation of different biomarkers with each of the indicators of parenchymal damage (HT, BE, IG, recanalization).

Discussion and conclusion

Definite conclusions are difficult to draw because of heterogeneity across studies. However, our review seems to confirm an association between some circulating biomarkers (particularly matrix metalloproteinase-9) and occurrence of parenchymal damage in ischemic stroke patients treated with revascularization therapies.

The initial glycemic variability is associated with early neurological deterioration in diabetic patients with acute ischemic stroke

The association between glycemic variability and early neurological deterioration (END) in acute ischemic stroke remains unclear. This study attempted to explore whether initial glycemic variability increases END in diabetic patients with acute ischemic stroke. We enrolled type 2 diabetic patients undergoing acute ischemic stroke from November 2015 to November 2016. A total of 336 patients within 72 h from stroke onset were included. The serum glucose levels were checked four times per day during the initial 3 hospital days. The standard deviation of blood glucose (SDBG) values and the mean amplitude of glycemic excursions (MAGE) were calculated for glycemic variability. END was defined as an increase in the National Institutes of Health Stroke Scale (NIHSS) ≥ 2 points between hospital days 0 and 5. The frequencies of END and HbA1c were significantly different in subjects grouped according to tertiles of MAGE (9.09, 12.07 and 50.00%, p < 0.001 for END; 7.36 ± 1.91, 7.83 ± 1.93 and 8.56 ± 1.79, p < 0.001 for HbA1c). Compared to patients without END, patients with END had significantly higher HbA1c levels (8.30 ± 1.92 vs 7.80 ± 1.93, p = 0.043), increased SDBG (3.42 ± 1.14 vs 2.60 ± 0.96, p < 0.001), and increased MAGE (6.46 ± 2.09 vs 4.59 ± 1.91, p < 0.001). In a multivariable logistic regression, stroke etiology (OR 0.675; 95% CI 0.485-0.940, p = 0.020), baseline NIHSS (OR 1.086; 95% CI 1.004-1.175, p = 0.040), and MAGE (OR 1.479; 95% CI 1.162-1.882, p = 0.001) were significantly associated with END. Initial glycemic variability is associated with END in diabetic patients with acute ischemic stroke.

Leukoaraiosis as an outcome predictor in the acute and subacute phases of stroke

INTRODUCTION

Leukoaraiosis (LA) is one of the neuroimaging features of cerebral small vessel disease and is associated with poor long-term prognosis. Areas covered: This narrative review focuses on the predictive role of LA on the evolution of the ischemic brain damage and on the clinical outcome in the subacute phase of stroke and in the short-term period afterwards. Expert commentary: LA predicts poorer tissue outcome and clinical prognosis also in acute and subacute stroke. In acute stroke, LA is associated with a less favorable fate of brain infarct and is a marker of increased risk of thrombolysis-related hemorrhagic transformation. The impaired cerebral microcirculation in LA patients may sustain the progression of ischemic lesion and enhance the bleeding risk. The short-term worse clinical outcome in ischemic stroke and intracranial hemorrhage patients with LA might be attributable to a state of altered brain connectivity. Endothelial failure, reduced micro-vessels density, and deficient collateral flow together with reduced functional reserve are some of the involved mechanisms. Future studies should aim at bridging the gap between the knowledge about LA pathophysiology and the therapeutic improvement of brain tissue perfusion and at producing data on early rehabilitation of stroke patients with LA at high disability risk.

Epoxyeicosatrienoic Acids are Mediated by EPHX2 Variants and may be a Predictor of Early Neurological Deterioration in Acute Minor Ischemic Stroke

Aim: To investigatethe association of plasma epoxyeicosatrienoic acids (EETs) with early neurologic deterioration (END), and whether EETs are mediated by EPHX2 variants in patients with minor ischemic stroke (MIS).

Method: This was a prospective, multi-center observational study in patients with acute MIS in the Chinese population.Plasma EETs levels were measured on admission. Single nucleotide polymorphisms (SNPs) of EPHX2rs751141 were genotyped using mass spectrometry. The primary outcome was END within 10 days after admission. END was defined as an increase in NIHSS of 2 or more points. The degree of disability was assessed using the modified Rankin Scale (mRS) at 3 months after admission.

Results: A total of 322 patients were enrolled, of which 85 patients (26.4%) experienced END. The mean EETs level was 64.1 ± 7.5 nmol/L. EETs levels were significantly lower in patients with END compared to patients without END. Frequency of EPHX2 rs751141 GG was higher in patients with END than in patients without END, and EPHX2 rs751141 GG genotype was associated with lower EETs levels. Low level (< 64.4 nmol/L) of EETs was an independent predictor of END (first and second quartiles) in multivariate analyses. END was associated with a higher risk of poor outcome (mRS scores 3–6) at 3 months.

Conclusion: END is fairly common and associated with poor outcomes in acute MIS. EPHX2 variants may mediate EETs levels, and low levels of EETs may be a predictor for END in acute MIS.

Potential biomarkers for predicting hemorrhagic transformation of ischemic stroke

Reperfusion therapy contributes to better clinical outcomes in patients with acute ischemic stroke but carries a more significant risk of hemorrhagic transformation (HT) compared to supportive care. Once HT occurs, the outcome is usually poor and this causes a dilemma in the treatment of ischemic stroke. Consequently, early prediction of HT would be extremely helpful for guiding precise treatment of ischemic stroke. In this review, we focus on summarizing biomarkers of HT and elucidating possible mechanisms so as to identify potential biomarkers for predicting HT.

Ischemic stroke outcome: A review of the influence of post-stroke complications within the different scenarios of stroke care

Stroke remains one of the main causes of death and disability worldwide. The challenge of predicting stroke outcome has been traditionally assessed from a general point of view, where baseline non-modifiable factors such as age or stroke severity are considered the most relevant factors. However, after stroke occurrence, some specific complications such as hemorrhagic transformations or post stroke infections, which lead to a poor outcome, could be developed. An early prediction or identification of these circumstances, based on predictive models including clinical information, could be useful for physicians to individualize and improve stroke care. Furthermore, the addition of biological information such as blood biomarkers or genetic polymorphisms over these predictive models could improve their prognostic value. In this review, we focus on describing the different post-stroke complications that have an impact in short and long-term outcome across different time points in its natural history and on the clinical-biological information that might be useful in their prediction.

Blood biomarkers in the early stage of cerebral ischemia

In ischemic stroke patients, blood-based biomarkers may be applied for the diagnosis of ischemic origin and subtype, prediction of outcomes and targeted treatment in selected patients. Knowledge of the pathophysiology of cerebral ischemia has led to the evaluation of proteins, neurotransmitters, nucleic acids and lipids as potential biomarkers. The present report focuses on the role of blood-based biomarkers in the early stage of ischemic stroke-within 72h of its onset-as gleaned from studies published in English in such patients. Despite growing interest in their potential role in clinical practice, the application of biomarkers for the management of cerebral ischemia is not currently recommended by guidelines. However, there are some promising clinical biomarkers, as well as the N-methyl-d-aspartate (NMDA) peptide and NMDA-receptor (R) autoantibodies that appear to identify the ischemic nature of stroke, and the glial fibrillary acidic protein (GFAP) that might be able to discriminate between acute ischemic and hemorrhagic strokes. Moreover, genomics and proteomics allow the characterization of differences in gene expression, and protein and metabolite production, in ischemic stroke patients compared with controls and, thus, may help to identify novel markers with sufficient sensitivity and specificity. Additional studies to validate promising biomarkers and to identify novel biomarkers are needed.

Docosahexaenoic acid attenuates hyperglycemia-enhanced hemorrhagic transformation after transient focal cerebral ischemia in rats

Hemorrhagic transformation (HT) is a feared complication of cerebral ischemic infarction, especially following the use of thrombolytic therapy. In this study, we examined whether docosahexaenoic acid (DHA; 22:6n-3), an omega-3 essential fatty acid family member, can protect the brain from injury and whether DHA can decrease the risk of HT enhanced by hyperglycemia after focal ischemic injury. Male Sprague-Dawley rats were injected with 50% dextrose (6ml/kg intraperitoneally) to induce hyperglycemia 10min before 1.5h of filament middle cerebral artery occlusion (MCAO) was performed. Treatment with DHA (10mg/kg) 5min before reperfusion reduced HT and further improved the 7-day neurological outcome. It also reduced infarct volume, which is consistent with the restricted DWI and T2WI hyperintensive area. Reduced Evans Blue extravasation and increased expression of collagen IV indicated the improved integrity of the blood-brain barrier (BBB) in DHA-treated rats. Moreover, DHA reduced the expression of the intercellular adhesion molecule-1 (ICAM-1) in the ischemic injured brain. Therefore, we conclude that DHA attenuated hyperglycemia-enhanced HT and improved neurological function by preserving the integrity of BBB and reducing inflammation.