Stroke Biomarkers Research Articles

Antimicrobial REG3A and Network Inflammatory Proteins Reflect Stroke Severity and Functional Impairment During Ischemic Stroke

Introduction Regenerating Family Member 3 Alpha (REG3A) is an antimicrobial protein secreted by the intestine and pancreas and is involved in immune-mediated inflammatory responses. In healthy individuals, REG3A is minimally expressed. However, acute-phase inflammatory mediators such as IL6 upregulate REG3A during inflammation, trauma, and cell dysregulation. The University of Kentucky Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC) protocol utilizes thrombectomy to isolate intracranial arterial blood (i.e. distal to thrombus) and systemic arterial blood (i.e. carotid) to better understand the pathophysiology of stroke. Initial proteomic analyses of 184 plasma proteins sampled during thrombectomy found that systemic arterial REG3A was increased during large vessel occlusion. The function of REG3A in neuroinflammation sequela of ischemic stroke has yet to be elucidated. Here, we examined the association of plasma REG3A levels with other signaling proteins in systemic plasma during stroke, and its correlation with clinical outcomes of stroke. Methods Systemic arterial plasma samples from 35 thrombectomy subjects underwent Proximity Extension Assay via Olink Proteomics. REG3A levels and inflammatory markers were examined using bivariate regressions. Biserial correlation examined the relationship between the National Institutes of Health Stroke Scale (NIHSS) upon hospital admission and REG3A. Multilinear regression determined predictability of infarct volume and edema volume by REG3A. Results: Systemic arterial levels of IL6 and REG3A were positively correlated (R=0.371, P=0.031). Higher levels of REG3A correlated with increased infarct and edema volume (R=0.416, P=0.014; R=0.418, P=0.014). Multilinear regression predicting infarct (R2=0.985,P<0.001) and edema volume (R2=0.998, P<0.001) each yielded a model with similar shared proteins, REG3A, CXCL11, TGFβ, IL17A, and NCAM1. NIHSS score at admission positively correlated with REG3A( R= 0.373, P=0.032). Conclusions Within a network of proteins, REG3A was predictive of infarct severity and increased neurologic deficits in patients with ELVO. Results of IL6 and REG3A uphold similar associations reported within the literature. Models predicting stroke severity yielded potential protein partners with REG3A, such as IL17, CXCL11, and TGFβ, which interact with REG3A in other inflammatory processes. REG3A function in stroke has yet to be understood, however this study reports novel findings demonstrating the relationship between REG3A and outcomes of stroke. Examining these associations will be critical in defining REG3A function during neuroinflammation and as a potential biomarker of large vessel occlusive stroke predicting clinical outcomes.

Microglial lnc-U90926 facilitates neutrophil infiltration in ischemic stroke via MDH2/CXCL2 axis

Dysregulated long non-coding RNAs (lncRNAs) have been shown to contribute to the pathogenesis of ischemic stroke. However, the potential role of lncRNAs in post-stroke microglial activation remains largely unknown. Here, we uncovered that lncRNA-U90926 was significantly increased in microglia exposed to ischemia/reperfusion both invivo and invitro. In addition, adenovirus-associated virus (AAV)-mediated microglial U90926 silencing alleviated neurological deficits and reduced infarct volume in experimental stroke mice. Microglial U90926 knockdown could reduce the infiltration of neutrophils into ischemic lesion site, which might be attributed to the downregulation of C-X-C motif ligand 2 (CXCL2). Mechanistically, U90926 directly bound to malate dehydrogenase 2 (MDH2) and competitively inhibited the binding of MDH2 to the CXCL2 3' untranslated region (UTR), thus protecting against MDH2-mediated decay of CXCL2 mRNA. Taken together, our study demonstrated that microglial U90926 aggravated ischemic brain injury via facilitating neutrophil infiltration, suggesting that U90926 might be a potential biomarker and therapeutic target for ischemic stroke.

Reduced Retinal Microvascular Perfusion in Patients With Stroke Detected by Optical Coherence Tomography Angiography.

Currently there is a shortage of biomarkers for stroke, one of the leading causes of death and disability in aging populations. Retinal vessels offer a unique and accessible “window” to study the microvasculature in vivo. However, the relationship between the retinal microvasculature and stroke is not entirely clear. To investigate the retinal microvascular characteristics in stroke, we recruited patients with stroke and age-matched control subjects from a tertiary hospital in China. The macular vessel density (VD) in the superficial capillary plexus (SCP) and deep capillary plexus (DCP), foveal avascular zone (FAZ) metrics, and optical coherence tomography angiography (OCTA) measured optic disc VD were recorded for analysis. A total of 189 patients with stroke and 195 control subjects were included. After adjusting for sex, visual acuity, systolic and diastolic blood pressure, a history of smoking, levels of hemoglobulin (HbA1c), cholesterol, and high-density lipoprotein (HDL), the macular VD of SCP and DCP in all sectors was decreased in patients with stroke. In the stroke group, the VD around the FAZ and the VD of the optic disk were lower. Logistic regression found the parafovea-superior-hemi VD of DCP > 54.53% [odds ratio (OR): 0.169] as a protective factor of stroke. Using the integration of all OCTA parameters and traditional risk factors, the area under the receiver operating characteristic (AUC) curve of distinguishing patients with stroke was 0.962, with a sensitivity of 0.944 and a specificity of 0.871. Our study demonstrates that the retinal VD is decreased in patients with stroke independently of the traditional risk factors of stroke, which may shed light on the monitoring of stroke using the retinal microvascular parameters.

C-Reactive Protein and White Blood Cell Count in Non-Infective Acute Ischemic Stroke Patients Treated with Intravenous Thrombolysis.

Background: Previous studies on inflammatory biomarkers in acute ischemic stroke (AIS) produced divergent results. We evaluated whether C-reactive protein (CRP) and white blood cell count (WBC) measured fasting 12–24 h after intravenous thrombolysis (IVT) were associated with outcome in AIS patients without concomitant infection. Methods: The study included 352 AIS patients treated with IVT. Excluded were patients with community-acquired or nosocomial infection. Outcome was measured on discharge and 90 days after stroke onset with the modified Rankin scale (mRS) and defined as poor outcome (mRS 3–6) or death (mRS = 6). Results: Final analysis included 158 patients (median age 72 years (interquartile range 63-82), 53.2% (n = 84) women). Poor outcome on discharge and at day 90 was 3.8-fold and 5.8-fold higher for patients with CRP ≥ 8.65 mg/L (fifth quintile of CRP), respectively, compared with first quintile (<1.71 mg/L). These results remained significant after adjustment for potential confounders (odds ratio (OR) on discharge = 10.68, 95% CI: 2.54–44.83, OR at day 90 after stroke = 7.21, 95% CI: 1.44–36.00). In-hospital death was 6.3-fold higher for patients with fifth quintile of CRP as compared with first quintile and remained independent from other variables (OR = 4.79, 95% CI: 1.29–17.88). Independent predictors of 90-day mortality were WBC < 6.4 × 109 /L (OR = 5.00, 95% CI: 1.49–16.78), baseline National Institute of Health Stroke Scale (NIHSS) score (OR = 1.13 per point, 95% CI: 1.01–1.25) and bleeding brain complications (OR = 5.53, 95% CI: 1.59–19.25) but not CRP ≥ 8.65 mg/L. Conclusions: Non-infective CRP levels are an independent risk factor for poor short- and long-term outcomes and in-hospital mortality in AIS patients treated with IVT. Decreased WBC but not CRP is a predictor for 90-day mortality.

Serum LRG1 as a novel biomarker for cardioembolic stroke

BackgroundIn recent years, LRG1 was found to be closely related to atrial fibrillation, heart failure, and myocardial remodeling after myocardial infarction. While its role in cerebral infarction was still controversial. We aimed to explore the value of LRG1 to identify the cardioembolic stroke. Methods283 acute ischemic stroke(AIS) patients and 169 controls were enrolled. The AIS patients were divided into a CE(cardiogenic embolism) group and a non-CE group. Serum LRG1 levels were quantified by ELISA. ResultsThe serum LRG1 levels were decreased in the AIS patients. CE group had higher serum LRG1 levels than the non-CE group. LRG1 was an independent risk factor for cardioembolic stroke. The area under the curve (AUC) was 0.768 with a sensitivity of 72.5% and specificity of 69.5%, which was not second to BNP and LAD. The combined predictive model we designed, including LRG1, BNP, and LAD, greatly improved the prediction effect. A positive correlation was shown between LRG1 and stroke severity in the CE group. Those who experienced poor outcomes had higher serum LRG1 levels compared with good ones. ConclusionSerum LRG1 was a promising indicator to predict cardioembolic stroke, as well as stroke severity and the 3-month prognosis of it.

Circulating miR-155 and JAK2/STAT3 Axis in Acute Ischemic Stroke Patients and Its Relation to Post-Ischemic Inflammation and Associated Ischemic Stroke Risk Factors.

Background“Micro RNAs and their target genes recently have been identified to play a crucial role in the molecular pathogenesis of post-stroke ischemic cellular injury, which elucidates their new role in ischemic stroke diagnosis and therapy”. Thus, we evaluated the relative serum expression of miR-155, an inflammatory micro RNA, and the mRNAs (JAK2/STAT3) in acute ischemic stroke patients and its associations with the inflammatory cytokine TNF-α and different stroke risk factors.Subjects and MethodsThe relative expression of serum miR-155 and mRNAs (JAK2/STAT3) was assessed using RT-PCR, serum TNF-α was measured using ELIZA in 46 acute ischemic stroke patients and 50 control subjects. Receiver operating characteristic (ROC) curve was constructed to assess the specificity and sensitivity of circulating miR-155, JAK2/STAT3 as biomarkers for acute ischemic stroke.ResultsCirculating miR-155, JAK2/STAT3 were significantly up-regulated among stroke patients (8.5, 2.9, 4.2 fold respectively, P<0.001) with significant increase in TNF-α (263.8 ± 10.7 pg/mL, P <0.001). MiR-155, JAK2/STAT3 were positively correlated with TNF-α. MiR-155, JAK2/STAT3 were significantly increased in stroke patients and associated with risk factors such as hypertension, carotid atherosclerosis, and atrial fibrillation. Our study revealed that miR-155 has diagnostic accuracy for acute ischemic stroke where AUC=0.9, (P<0.001).ConclusionThe elevated expressions of circulating miR-155, JAK2/STAT3, and TNF-α in acute ischemic stroke patients could trigger post-stroke cellular inflammation. MiR-155 could be used as potential inflammatory biomarker for acute ischemic stroke. However, further clinical studies are still needed to determine the exact role of miRNAs and different signal transduction expressions in the stage of acute ischemic stroke.

Trimethyllysine, vascular risk factors and outcome in acute ischemic stroke (MARK-STROKE).

Trimethyllysine (TML) is involved in the generation of the pro-atherogenic metabolite trimethylamine-N-oxide (TMAO) by gut microbiota. In clinical studies, elevated TML levels predicted major adverse cardiovascular events (MACE) in patients with acute or stable coronary artery disease (CAD). In contrast to cardiovascular patients, the role of TML in patients with acute cerebral ischemia is unknown. Here, we evaluated circulating TML levels in 374 stroke patients from the prospective biomarkers in stroke (MARK-STROKE) study. Compared with 167 matched healthy controls, acute ischemic stroke patients had lower median TML plasma concentrations, i.e. 0.71 vs. 0.47µmol/L (p < 0.001) and this difference persisted after adjusting for age and sex. TML plasma concentrations were associated with age, serum creatinine, glucose, cholesterol and lysine. Patients with prevalent arterial hypertension, atrial fibrillation or a history of myocardial infarction had increased TML levels, but this observation was not independent of age, sex and GFR. In 274 patients, follow-up data were available. During a median follow-up of 284 [25th-75th percentile: 198, 431] days, TML was not associated with incident MACE (stroke, myocardial infarction, death). In summary, our data suggests a different role of TML in acute ischemic stroke compared with CAD patients.

Serum calcium and long-term outcome after ischemic stroke: Results from the China National stroke registry III

Background and aimsSerum calcium abnormality is associated with adverse cardiovascular outcomes, but the effects of serum calcium level on stroke outcomes remain unknown. We aimed to assess the relationship between serum calcium level and 1-year outcomes in patients with acute ischemic stroke and transient ischemic attack. MethodsWe included 9375 stroke patients from the China National Stroke Registry III for analysis. Participants were divided into 4 groups according to albumin corrected-calcium quartiles. Composite end point comprised recurrent stroke, myocardial infarction, other ischemic vascular events, and all-cause mortality. Multivariable Cox or logistic regression was used to evaluate the independent association of albumin corrected-calcium with all-cause mortality, recurrent stroke, composite end point, and poor functional outcome (modified Rankin Scale score ≥3). ResultsCompared with the lowest calcium quartile (<2.16 mmol/L), the adjusted hazard ratio (95% CI) of the top quartile (≥2.31 mmol/L) was 1.56 (1.11–2.18) for all-cause mortality, 1.06 (0.87–1.28) for recurrent stroke and 1.08 (0.90–1.01) for composite end point, and the adjusted odds ratio for poor functional outcome was 1.18 (0.96–1.44). The addition of serum calcium to conventional risk factors improved risk prediction of all-cause mortality, leading to a small but significant increase in C-statistics and reclassification with non-significant integrated discrimination improvement (C-statistics, p = 0.02; net reclassification index 11.8%, p = 0.038; integrated discrimination improvement 0.08%, p = 0.42). ConclusionsHigh serum calcium levels at baseline were associated with all-cause mortality at 1-year after ischemic stroke, suggesting that serum calcium may be a potential prognostic biomarker and therapeutic target for ischemic stroke.

The 3'-UTR Polymorphisms in the Thymidylate Synthase (TS) Gene Associated with the Risk of Ischemic Stroke and Silent Brain Infarction.

Thymidylate synthase (TS) is a key gene involved in the repair of DNA damage and DNA synthesis that plays an important role in vascular development and recovery. In particular, TS gene polymorphisms play a major role in the progression of vascular disease and cancer metastasis. Therefore, the aim of this study was to investigate the association of three TS polymorphisms (1100T>C [rs699517], 1170A>G [rs2790], and 1494ins/del [rs151264360]) with ischemic stroke and silent brain infarction (SBI) in Koreans. A total of 1299 participants (507 stroke patients, 383 SBI patients, and 409 controls) were enrolled in the study. Genotyping of the three TS polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism analysis. To examine the association between TS gene polymorphisms and the diseases, we performed statistical analyses, including multivariable logistic regression and Fisher’s exact tests. We found that TS 1100T>C and 1170A>G genotypes were strongly associated with ischemic stroke and SBI susceptibility. More specifically, the TS 1100T>C polymorphism was associated with the likelihood of ischemic stroke (TT vs. CC: AOR = 2.151, 95% CI = 1.275–3.628, P = 0.004) and SBI (TT vs. TC+CC: AOR = 1.443, 95 % CI = 1.009–2.063, P = 0.045). In contrast, the TS 1170A > G polymorphism exhibited lower correlation with the risk of stroke (AA vs. GG: AOR = 0.284, 95% CI = 0.151–0.537, P < 0.0001) and SBI (AA vs. GG: AOR = 0.070, 95% CI = 0.016–0.298, P = 0.0002). Furthermore, we confirmed that the TS 1100T>C polymorphism was synergistic with low folic acid levels (AOR = 6.749, P < 0.0001). Altogether, these results suggest that TS 1100T>C and 1170A > G polymorphisms are associated with the risk of ischemic stroke and SBI, and our study provides the first evidence that 3′-UTR variants in TS are potential biomarkers in ischemic stroke and SBI.

LncRNA MALAT1 aggravates oxygen\u2010glucose deprivation/reoxygenation-induced neuronal endoplasmic reticulum stress and apoptosis via the miR-195a-5p/HMGA1 axis

BackgroundThis study aimed to investigate the potential role and molecular mechanism of lncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in cerebral ischemia/reperfusion injury.ResultsUsing an oxygen-glucose deprivation/reoxygenation (OGD/R) cell model, we determined that the expression of MALAT1 was significantly increased during OGD/R. MALAT1 knockdown reversed OGD/R-induced apoptosis and ER stress. Mechanistically, MALAT1 promoted OGD/R-induced neuronal injury through sponging miR-195a-5p to upregulating high mobility group AT-hook1 (HMGA1).ConclusionsCollectively, these data demonstrate the mechanism underlying the invovlvement of MALAT1 in cerebral ischemia/reperfusion injury, thus providing translational evidence that MALAT1 may serve as a novel biomarker and therapeutic target for ischemic stroke.

Abstract P657: Soluble Receptor for Advanced Glycation End Products and Subtypes Are Protective Biomarkers of Functional Outcome but Not Those of Recurrence in Acute Ischemic Stroke

Background and purpose: Soluble isoforms of receptor for advanced glycation end products (sRAGE) and subtypes have been recognized as contradictory biomarkers of ischemic stroke. We sought to investigate whether the plasma levels of sRAGE and subtypes can predict unfavorable outcome and recurrence in acute ischemic stroke patients. Methods: The data used in this study was from the Third China National Stroke Registy (CNSR III), which was a nationwide, prospective cohort study to register acute ischemic stroke and transient ischemic attack patients. Plasma levels of sRAGE and subtypes were tested by enzyme-linked immunoabsorbent assay (ELISA) method and demonstrated by quartiles. Cox proportional hazards model was used to analysis the association of sRAGE and subtypes with unfavorable outcomes or stroke recurrence at 3- and 12-month in acute ischemic stroke patients, respectively. Unfavorable outcome was defined as modified Rankin Scale (mRS) 3-6. Results: Three thousand one hundred and eighty-nine acute ischemic stroke patients were included and tested for plasma level of sRAGE and subtypes (cRAGE and esRAGE) in this study. Mean age was 62.8±11.5 years and 2161 (67.8%) were male. At 3- and 12-month, there were 426 (13.5%) and 409 (13.1%) patients with an unfavorable outcome and 185 (5.9%) and 293 (9.2%) patients with stroke recurrence, respectively. Refered by quartile one of sAGRE, the adjusted hazard ratios (aHRs) and 95% confidence intervals (95% CIs) of unfavorable outcomes in quartile two to four were 0.81 (0.59-1.10), 0.66 (0.48-0.92) and 0.65 (0.47-0.91) at 3-month and 0.79 (0.58-1.08), 0.61 (9.44-0.85) and 0.66 (0.48-0.91) at 12-month; those of stroke recurrence in quartile two to four were 0.99 (0.66-1.49), 0.99 (0.66-1.49) and 1.02 (0.68-1.54) at 3-month and 1.05 (0.76-1.45), 0.95 (0.68-1.32) and 1.07 (0.77-1.48) at 12-month, respectively. Same data trends were found in subtypes cRAGE and esRAGE. Conclusion: Plasma levels of sRAGE and subtypes were protective biomarkers of unfavorable outcomes but not those of stroke recurrence in acute ischemic stroke patients.

Abstract P58: Motor Recovery After Chronic Stroke Correlates With Diffusion Tensor Measures of Ipsilesional Cerebral and Cerebellar White Matter Integrity

Introduction: We aimed to determine whether white matter (WM) tract integrity improved after a brain-computer interface (BCI) rehabilitation program for chronic stroke patients with upper extremity weakness. Mean diffusivity (MD) was calculated from diffusion tensor imaging (DTI) and is an indication of the integrity of axons and myelination in WM. MD is a biomarker in subacute stroke for post-stroke motor deficits and recovery. Methods: DTI scans were performed with 9 chronic hemiplegic stroke patients within 2 weeks of initiation and completion of a 12-week BCI rehabilitation program. All patients were a minimum of 6 months post-stroke. MD was then calculated using DSI-Studio for WM tracts in each patient at both pre- and post-therapy time points. Motor function was evaluated at these time points using the upper extremity portion of the Fugl-Meyer Assessment (UEFM). Voxelwise statistical analysis comparing pre- and post-intervention MD values was carried out using tract-based spatial statistics (TBSS). Relationships between MD measures in regions of interest and changes in motor function were estimated with Spearman correlations. Results: Voxelwise analysis using TBSS showed no significant group-level change in MD of WM tracts throughout the brain after completing BCI rehabilitation. However, the change in MD in ipsilesional cerebral WM was positively correlated with UEFM change (Spearman’s rho = 0.75, p = 0.02) as was the pre-BCI MD in the ipsilesional cerebellar WM (rho = 0.78, p = 0.01). The correlations between contralesional MD measures and UEFM change were not statistically significant. Conclusion: Correlation between changes in mean diffusivity of ipsilesional cerebral white matter and motor improvement in chronic stroke supports the literature that recovery may be mediated by axonal remyelination and regeneration. Furthermore, we find that pre-therapy, ipsilesional cerebellar white matter MD correlates with motor recovery and as such may serve as a predictive measure of the effectiveness of BCI therapy for patients.

Stimuli‐Responsive Nanotheranostics

Stimuli‐Responsive Nanotheranostics

Acute Stroke Biomarkers: Are We There Yet?

Background: Distinguishing between stroke subtypes and knowing the time of stroke onset are critical in clinical practice. Thrombolysis and thrombectomy are very effective treatments in selected patients with acute ischemic stroke. Neuroimaging helps decide who should be treated and how they should be treated but is expensive, not always available and can have contraindications. These limitations contribute to the under use of these reperfusion therapies.Aim: An alternative approach in acute stroke diagnosis is to identify blood biomarkers which reflect the body's response to the damage caused by the different types of stroke. Specific blood biomarkers capable of differentiating ischemic from hemorrhagic stroke and mimics, identifying large vessel occlusion and capable of predicting stroke onset time would expedite diagnosis and increase eligibility for reperfusion therapies.Summary of Review: To date, measurements of candidate biomarkers have usually occurred beyond the time window for thrombolysis. Nevertheless, some candidate markers of brain tissue damage, particularly the highly abundant glial structural proteins like GFAP and S100β and the matrix protein MMP-9 offer promising results. Grouping of biomarkers in panels can offer additional specificity and sensitivity for ischemic stroke diagnosis. Unbiased “omics” approaches have great potential for biomarker identification because of greater gene, protein, and metabolite coverage but seem unlikely to be the detection methodology of choice because of their inherent cost.Conclusion: To date, despite the evolution of the techniques used in their evaluation, no individual candidate or multimarker panel has proven to have adequate performance for use in an acute clinical setting where decisions about an individual patient are being made. Timing of biomarker measurement, particularly early when decision making is most important, requires urgent and systematic study.

Increased Serum Complement C3 Levels Are Associated With Adverse Clinical Outcomes After Ischemic Stroke.

Complement C3 has been implicated in inflammation and ischemia/reperfusion injury, but its impact on the prognosis of ischemic stroke remains unclear. Aim of this study was to prospectively investigate the association between serum complement C3 and adverse clinical outcomes after ischemic stroke. We measured serum complement C3 levels for 3474 patients with ischemic stroke in 26 participating hospitals and collected data of clinical outcomes at 3 months after ischemic stroke. The primary outcome was composite outcome of death and major disability (modified Rankin Scale score ≥3) at 3 months after stroke onset and secondary outcomes included major disability, death, and vascular events. During 3 months of follow-up, 866 participants (25.4%) developed primary outcome. After multivariate adjustment, elevated serum complement C3 levels were associated with increased risk of primary outcome (odds ratio, 1.30 [95% CI, 1.02-1.65]; Ptrend=0.038) when 2 extreme tertiles were compared. Each SD increase of log-transformed complement C3 was associated with 13% (95% CI, 2%-25%) increased risk of primary outcome. Multivariable-adjusted spline regression model showed a linear relationship between serum complement C3 and the risk of primary outcome (Plinearity=0.022). Addition of serum complement C3 to conventional risk factors significantly improved the risk prediction of primary outcome (net reclassification index: 8.87%, P=0.028; integrated discrimination index: 0.19%, P=0.029). High serum complement C3 levels at baseline were associated with increased risks of adverse clinical outcomes at 3 months after ischemic stroke, suggesting that serum complement C3 may be a valuable prognostic biomarker for ischemic stroke.

Affimer-Based Europium Chelates Allow Sensitive Optical Biosensing in a Range of Human Disease Biomarkers.

The protein biomarker measurement has been well-established using ELISA (enzyme-linked immunosorbent assay), which offers good sensitivity and specificity, but remains slow and expensive. Certain clinical conditions, where rapid measurement or immediate confirmation of a biomarker is paramount for treatment, necessitate more rapid analysis. Biosensors offer the prospect of reagent-less, processing-free measurements at the patient’s bedside. Here, we report a platform for biosensing based on chelated Eu3+ against a range of proteins including biomarkers of cardiac injury (human myoglobin), stroke (glial fibrillary acidic protein (GFAP)), inflammation (C-reactive protein (CRP)) and colorectal cancer (carcinoembryonic antigen (CEA)). The Eu3+ ions are chelated by modified synthetic binding proteins (Affimers), which offer an alternative targeting strategy to existing antibodies. The fluorescence characteristics of the Eu3+ complex with modified Affimers against human myoglobin, GFAP, CRP and CEA were measured in human serum using λex = 395 nm, λem = 590 and 615 nm. The Eu3+-Affimer based complex allowed sensitive detection of human myoglobin, GFAP, CRP and CEA proteins as low as 100 fM in (100-fold) diluted human serum samples. The unique dependence on Eu3+ fluorescence in the visible region (590 and 615 nm) was exploited in this study to allow rapid measurement of the analyte concentration, with measurements in 2 to 3 min. These data demonstrate that the Affimer based Eu3+ complexes can function as nanobiosensors with potential analytical and diagnostic applications.

Retraction Note to: A SERS-based lateral flow assay for the stroke biomarker S100-β.

A surface-enhanced Raman scattering (SERS)-based lateral flow assay (LFA) is described for the quantitative analysis of the proteinic stroke biomarker S100-β that has to be detected at very low concentration levels. The Raman reporter 5,5′-dithiobis-2-nitrobenzoic acid (DTNB) on gold nanoparticles (GNPs) was employed as the SERS tags. They are shown to perform much better than bare GNPs in LF strips. The S100-β protein can be detected by this method with very low detection limits by monitoring the intensity of the characteristic Raman peak of the S100-β protein-conjugated GNPs at 1332 cm−1. Under optimized conditions, the assay works in the 1 pg·mL−1 to 40 ng·mL−1 S100-β concentration range, and the detection limit is as low as 0.14 pg·mL−1. This is lower by a factor of 3 compared to colorimetric or fluorimetric methods.

Circulating Exosomes of Neuronal Origin as Potential Early Biomarkers for Development of Stroke.

Stroke is one of the major causes of morbidity and mortality globally, with devastating effects. It is diagnosed mainly by clinical assessment and brain imaging; however, it is challenging to discriminate stroke from similar conditions with parallel presentations. While brain imaging provides detection of stroke infarcts, it does not provide useful information on the biology and prognosis of the underlying disease process. The complex pathophysiology of stroke infarcts is a barrier in developing sensitive diagnostic tools, which consequently has a detrimental effect on development of treatment regimens. Early diagnosis of stroke is vital for better management, but currently there is no diagnostic blood-based biomarker. The cargo of exosomes can give an insight into the physiological or pathophysiological status of the cell. Exosomes have gained great interest as a means of intercellular communication and recently have been explored as a potential biomarker tool. Circulating exosomes in the blood result from of a contribution from all tissues. The sub-population of exosomes released from brain cells circulating in body fluids are known as neuronal exosomes. This overview presents the vital diagnostic function that could be performed by circulating exosomes of neuronal origin in identifying the subtype of stroke, its severity, and the recovery stages. A number of potential biomarkers that are obtained from circulating exosomes have showed promising potential to function as stroke biomarkers; however, further work is needed to characterize the neuronal exosomes and its payload and to determine the pathways it uses in the complex pathophysiology of stroke. The identification is a subset of exosomal biomarkers that are specific to stroke will enhance the early detection and prognosis of the disease.

Role of Blood-Based Biomarkers in Ischemic Stroke Prognosis: A Systematic Review.

Outcome prognostication in ischemic stroke patients remains challenging due to limited predictive properties of existing models. Blood-based biomarkers might provide additional information to established prognostic factors. We intended to identify the most promising prognostic biomarkers in ischemic stroke, their incremental prognostic value, and whether their predictive value differs among etiologies. We searched MEDLINE (Ovid) and Institute for Scientific Information Web of Knowledge for articles reporting the predictive performance of blood-based biomarkers measured up to 7 days after ischemic stroke and reporting functional outcome or death at least 7 days after stroke. This work updates a previous systematic review (up to January 2007), follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and was registered (International Prospective Register of Systematic Reviews PROSPERO 2018; https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42018094671). Two hundred ninety-one articles published between January 2007 and August 2018 comprising 257 different biomarkers met inclusion criteria. Median sample size was 232 (interquartile range, 110-455); 260 (89%) articles reported regression analyses with 78% adjusting for stroke severity, 82% for age, 67% for both, and 9% for none of them; 37% investigated discrimination, 5% calibration, and 11% reclassification. Including publications from a previous systematic review (1960-January 2007), natriuretic peptides, copeptin, procalcitonin, mannose-binding lectin, adipocyte fatty acid-binding protein, and cortisol were the biomarkers most consistently associated with poor outcome in higher-quality studies showing an incremental value over established prognostic factors. Other biomarkers were less consistently associated with poor outcome or were reported in lower quality studies. High heterogeneity among studies precluded the performance of a meta-analysis. The number of reports on prognostic blood-based biomarkers in ischemic stroke increased 3.5-fold in the period January 2007 to August 2018. Although sample size increased, methodological flaws are still common. Natriuretic peptides and markers of inflammation, atherogenesis, and stress response are the most promising prognostic biomarkers among identified studies.

The bioinformatic identification of proteins with varying levels of post-translational modifications in experimental ischemic stroke in mice

The experimental data obtained by Simats A. et al. (Molecular and Cellular Proteomics, 2020, 19(12), 1921-1936) was analysed using a bioinformatic approach. Original experimental results available in the ProteomeXchange database were obtained using a comprehensive multidomain approach to identify potential blood biomarkers in ischemic stroke in mice. The identification of peptides with post-translational modification (PTM) was performed by us using the raw data (accession code PXD016538). Only phosphorylation and deamination were considered as PTMs. Different combinations of data sets (ischemic tissue with intact tissue, ischemic tissue with control taken from mice after sham surgery, etc.) were compared both in terms of the ratio of abundance for the modified peptide to the unmodified variant and in terms of absolute values of abundance. The most likely change in precisely PTM levels was shown for 27 proteins, which include dynamin, glycogen phosphorylase and 70 kDa heat shock protein.