Background and Purpose: 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. Methods: 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). Results: 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. Conclusions: 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.

Stroke is the fifth leading cause of death and the most frequent cause of disability worldwide. Currently, stroke diagnosis is based on neuroimaging; therefore, the lack of a rapid tool to diagnose stroke is still a major concern. In addition, therapeutic approaches to combat ischemic stroke are still scarce, since the only approved therapies are directed toward restoring blood flow to the affected brain area. However, due to the reduced time window during which these therapies are effective, few patients benefit from them; therefore, alternative treatments are urgently needed to reduce stroke brain damage in order to improve patients’ outcome. The inflammatory response triggered after the ischemic event plays an important role in the progression of stroke; consequently, the study of inflammatory molecules in the acute phase of stroke has attracted increasing interest in recent decades. Here, we provide an overview of the inflammatory processes occurring during ischemic stroke, as well as the potential for these inflammatory molecules to become stroke biomarkers and the possibility that these candidates will become interesting neuroprotective therapeutic targets to be blocked or stimulated in order to modulate inflammation after stroke.

Background: CCL23 role in the inflammatory response after acute brain injuries remains elusive. Here, we evaluated whetherCCL23 blood levels associate with acquired cerebral lesions and determinedCCL23 predictive capacity for assessing stroke prognosis. We used preclinical models to study theCCL23 homologous chemokines in rodents,CCL9 andCCL6.Methods: BaselineCCL23 blood levels were determined on 245 individuals, including ischaemic strokes (IS), stroke mimics and controls. Temporal profile of circulatingCCL23 was explored from baseline to 24 h in 20 of theIS. In an independent cohort of 120ISwith a 3‐month follow‐up,CCL23 blood levels were included in logistic regression models to predictISoutcome.CCL9/CCL6 cerebral expression was evaluated in rodent models of brain damage. Both chemokines were also profiled in circulation and histologically located on brain following ischaemia.Results: BaselineCCL23 blood levels did not discriminateIS, but permitted an accurate discrimination of patients presenting acute brain lesions (P = 0.003).ISexhibited a continuous increase from baseline to 24 h in circulatingCCL23 (P < 0.001). BaselineCCL23 blood levels resulted an independent predictor ofISoutcome at hospital discharge (OR_adj: 19.702 [1.815–213.918],P = 0.014) and mortality after 3 months (OR_adj: 21.47 [3.434–134.221],P = 0.001).In preclinics, expression of rodent chemokines in neurons following cerebral lesions was elevated.CCL9 circulating levels decreased early after ischaemia (P < 0.001), whereasCCL6 did not alter within the first 24 h after ischaemia.Conclusions: Although preclinical models do not seem suitable to characterizeCCL23, it might be a novel promising biomarker for the early diagnosis of cerebral lesions and might facilitate the prediction of stroke patient outcome.

Cerebral ischemia entails rapid tissue damage in the affected brain area causing devastating neurological dysfunction. How each component of the neurovascular unit contributes or responds to the ischemic insult in the context of the human brain has not been solved yet. Thus, the analysis of the proteome is a straightforward approach to unraveling these cell proteotypes. In this study, post-mortem brain slices from ischemic stroke patients were obtained corresponding to infarcted (IC) and contralateral (CL) areas. By means of laser microdissection, neurons and blood brain barrier structures (BBB) were isolated and analyzed using label-free quantification. MS data are available via ProteomeXchange with identifier PXD003519. Ninety proteins were identified only in neurons, 260 proteins only in the BBB and 261 proteins in both cell types. Bioinformatics analyses revealed that repair processes, mainly related to synaptic plasticity, are outlined in microdissected neurons, with nonexclusive important functions found in the BBB. A total of 30 proteins showing p < 0.05 and fold-change> 2 between IC and CL areas were considered meaningful in this study: 13 in neurons, 14 in the BBB and 3 in both cell types. Twelve of these proteins were selected as candidates and analyzed by immunohistofluorescence in independent brains. The MS findings were completely verified for neuronal SAHH2 and SRSF1 whereas the presence in both cell types of GABT and EAA2 was only validated in neurons. In addition, SAHH2 showed its potential as a prognostic biomarker of neurological improvement when analyzed early in the plasma of ischemic stroke patients. Therefore, the quantitative proteomes of neurons and the BBB (or proteotypes) after human brain ischemia presented here contribute to increasing the knowledge regarding the molecular mechanisms of ischemic stroke pathology and highlight new proteins that might represent putative biomarkers of brain ischemia or therapeutic targets.

The limited accessibility to the brain has turned the cerebrospinal fluid (CSF) into a valuable source that may contribute to the complete understanding of the stroke pathophysiology. Here we have described the CSF proteome in the hyper-acute phase of cerebral ischemia by performing an aptamer-based proteomic assay (SOMAscan) in CSF samples collected before and 30 min after male Wistar rats had undergone a 90 min Middle Cerebral Artery Occlusion (MCAO) or sham-surgery. Proteomic results indicated that cerebral ischemia acutely increased the CSF levels of 716 proteins, mostly overrepresented in leukocyte chemotaxis and neuronal death processes. Seven promising candidates were further evaluated in rat plasma and brain (CKB, CaMK2A, CaMK2B, CaMK2D, PDXP, AREG, CMPK). The 3 CaMK2 family-members and CMPK early decreased in the infarcted brain area and, together with AREG, co-localized with neurons. Conversely, CKB levels remained consistent after the insult and specifically matched with astrocytes. Further exploration of these candidates in human plasma revealed the potential of CKB and CMPK to diagnose stroke, while CaMK2B and CMPK resulted feasible biomarkers of functional stroke outcome. Our findings provided insights into the CSF proteome following cerebral ischemia and identified new outstanding proteins that might be further considered as potential biomarkers of stroke.