Common and specific proteins and pathways in heart and cerebral ischemia.

OBJECTIVE: To understand the similarities and differences between acute ischemic stroke and acute myocardial infarction (AMI) to help in the development of specific or common treatment strategies. METHODS: Using an aptamer-based proteomic array, we measured and compared 1310 circulating proteins in the blood of 40 patients with AIS, 9 patients with AMI, and 31 healthy controls. Pathway enrichment analysis was performed using GSEA and g:profiler. RESULTS: Ninety-four proteins were differentially expressed in AIS, and 284 were differentially expressed in AMI. Of these, 8 were specific to cerebral ischemia, and 197 were specific to myocardial infarction. Forty-two proteins were altered in both ischemia processes. Most altered pathways in AIS could be classified as immune response, cell cycle processing, molecular transport, or signaling. Pathways altered in AMI were mostly related to lipid metabolism and transport, highlighting cholesterol metabolic processes and estrogen signaling. In both types of ischemia, we found pathways related to metabolism, specifically purine metabolism, and signaling processes, such as TNF signaling or MAPK1/3. CONCLUSIONS: The present study revealed proteins and pathways that were specifically altered in cerebral ischemia, in cardiac ischemia, or in both diseases, providing information on the similarities and differences of ischemic conditions. The role of common and specific proteins and pathways should be explored in detail to find possible therapeutic targets.

A Mouse Brain-based Multi-omics Integrative Approach Reveals Potential Blood Biomarkers for Ischemic Stroke.

Stroke remains a leading cause of death and disability worldwide. Despite continuous advances, the identification of key molecular signatures in the hyper-acute phase of ischemic stroke is still a primary interest for translational research on stroke diagnosis, prognosis, and treatment. Data integration from high-throughput -omics techniques has become crucial to unraveling key interactions among different molecular elements in complex biological contexts, such as ischemic stroke. Thus, we used advanced data integration methods for a multi-level joint analysis of transcriptomics and proteomics data sets obtained from mouse brains at 2 h after cerebral ischemia. By modeling net-like correlation structures, we identified an integrated network of genes and proteins that are differentially expressed at a very early stage after stroke. We validated 10 of these deregulated elements in acute stroke, and changes in their expression pattern over time after cerebral ischemia were described. Of these, CLDN20, GADD45G, RGS2, BAG5, and CTNND2 were next evaluated as blood biomarkers of cerebral ischemia in mice and human blood samples, which were obtained from stroke patients and patients presenting stroke-mimicking conditions. Our findings indicate that CTNND2 levels in blood might potentially be useful for distinguishing ischemic strokes from stroke-mimicking conditions in the hyper-acute phase of the disease. Furthermore, circulating GADD45G content within the first 6 h after stroke could also play a key role in predicting poor outcomes in stroke patients. For the first time, we have used an integrative biostatistical approach to elucidate key molecules in the initial stages of stroke pathophysiology and highlight new notable molecules that might be further considered as blood biomarkers of ischemic stroke.

Evaluation and Characterization of Post-Stroke Lung Damage in a Murine Model of Cerebral Ischemia.

After stroke and other brain injuries, there is a high incidence of respiratory complications such as pneumonia or acute lung injury. The molecular mechanisms that drive the brain-lung interaction post-stroke have not yet been elucidated. We performed transient middle cerebral artery occlusion (MCAO) and sham surgery on C57BL/6J mice and collected bronchoalveolar lavage fluid (BALF), serum, brain, and lung homogenate samples 24 h after surgery. A 92 proteins-panel developed by Olink Proteomics® was used to analyze the content in BALF and lung homogenates. MCAO animals had higher protein concentration levels in BALF than sham-controls, but these levels did not correlate with the infarct volume. No alteration in alveolar-capillary barrier permeability was observed. A total of 12 and 14 proteins were differentially expressed between the groups (FDR < 0.1) in BALF and lung tissue homogenates, respectively. Of those, HGF, TGF-α, and CCL2 were identified as the most relevant to this study. Their protein expression patterns were verified by ELISA. This study confirmed that post-stroke lung damage was not associated with increased lung permeability or cerebral ischemia severity. Furthermore, the dysregulation of HGF, TGF-α, and CCL2 in BALF and lung tissue after ischemia could play an important role in the molecular mechanisms underlying stroke-induced lung damage.

Association of blood-based biomarkers with radiologic markers and cognitive decline in atrial fibrillation patients.

BACKGROUND: Atrial fibrillation (AF) has been associated with an increased risk of silent brain infarcts (SBI) and cognitive impairment, even in patients with low embolic risk. We aimed to test the association between 11 blood-biomarkers representing different AF-related pathways, and SBI, white matter hyperintensities (WMH), and cognitive decline in patients with AF and low embolic risk. METHODS: The present study followed a cross-sectional design. 70 patients with a history of AF and CHADS2 score ≤1, and 10 controls with neither AF nor SBI were included. All patients underwent a 3T brain MRI. Cortical and large subcortical ischemic lesions were considered presumed embolic origin lesions. White matter hyperintensities (WMH) were measured according to the Fazekas scale. A subset of patients underwent cognitive evaluation with the MoCA test. Circulating proteins were measured under blind conditions in a laboratory at Roche Diagnostics, Germany. RESULTS: 45 patients presented SBI in the MRI, and 25 did not. Ang-2, FGF-23, and BMP-10 were increased in patients with SBI. Ang-2 was elevated only in patients with embolic infarcts, whereas FGF-23 and BMP-10 tended to be elevated in patients with both types of infarcts. Ang-2 (OR = 1.56 [0.94-2.59], p = 0.087), and BMP-10 (OR = 4.83 [0.99-23.60], p = 0.052) were the biomarkers that showed the highest association with SBI when entered in a multivariable logistic regression model corrected by age. No biomarker was found associated with WMH or mild cognitive impairment. CONCLUSIONS: BMP-10, and Ang-2 were increased in patients with SBI. Its usefulness to detect SBI in AF patients should be further explored.

Single Cell Immuno-Laser Microdissection Coupled to Label-Free Proteomics to Reveal the Proteotypes of Human Brain Cells After Ischemia.

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.

Venous and arterial TNF-R1 predicts outcome and complications in acute subarachnoid hemorrhage.

BACKGROUND: There is increasing evidence for the role of inflammation in clinical outcome after subarachnoid hemorrhage (SAH). Specifically, the TNF-alfa(α) pathway seems to be relevant after SAH. Although the TNF-α main receptor, TNF-R1 is associated with aneurysm growth and rupture, its relation to prognosis is unknown. We sought to compare TNF-R1 levels in peripheral venous blood and arterial blood closer to the ruptured aneurysm to study the association of TNF-R1 blood levels with poor prognosis (modified Rankin Scale > 2 at discharge, 3 and 6 months) and complications (hydrocephalus or delayed cerebral ischemia/DCI) following SAH. METHODS: We included consecutive SAH patients admitted in the first 72 h of symptoms. Blood samples were simultaneously collected from a peripheral vein and from the main parent artery of the aneurysm. Levels of TNF-R1 were measured using enzyme-linked immunosorbent assays. RESULTS: We analyzed 58 patients. Arterial and venous levels of TNF-R1 were correlated (R = 0.706, p < 0.001). In multivariate regression analysis, venous TNF-R1 was an independent predictor of poor outcome at 6 months after adjusting by age and sex [odds ratio (OR) 11.63; 95% CI 2.09-64.7, p = 0.005] and after adjusting by Glasgow Coma Scale and Fisher scales (OR 8.74; 95% CI 1.45-52.7, p = 0.018). There was no association of TNF-R1 with DCI. A cut-off for arterial TNF-R1 of 1523.7 pg/mL had 75% sensitivity/66% specificity for the prediction of hydrocephalus. CONCLUSION: Levels of venous TNF-R1 are associated with poor outcome in SAH. A specific association was found between levels of arterial TNF-R1 and hydrocephalus. These results are consistent with the role of TNF-α pathway in SAH and need to be validated in larger cohorts.

Blood Biomarkers for the Early Diagnosis of Stroke: The Stroke-Chip Study.

BACKGROUND AND PURPOSE: Stroke diagnosis could be challenging in the acute phase. We aimed to develop a blood-based diagnostic tool to differentiate between real strokes and stroke mimics and between ischemic and hemorrhagic strokes in the hyperacute phase. METHODS: The Stroke-Chip was a prospective, observational, multicenter study, conducted at 6 Stroke Centers in Catalonia. Consecutive patients with suspected stroke were enrolled within the first 6 hours after symptom onset, and blood samples were drawn immediately after admission. A 21-biomarker panel selected among previous results and from the literature was measured by immunoassays. Outcomes were differentiation between real strokes and stroke mimics and between ischemic and hemorrhagic strokes. Predictive models were developed by combining biomarkers and clinical variables in logistic regression models. Accuracy was evaluated with receiver operating characteristic curves. RESULTS: From August 2012 to December 2013, 1308 patients were included (71.9% ischemic, 14.8% stroke mimics, and 13.3% hemorrhagic). For stroke versus stroke mimics comparison, no biomarker resulted included in the logistic regression model, but it was only integrated by clinical variables, with a predictive accuracy of 80.8%. For ischemic versus hemorrhagic strokes comparison, NT-proBNP (N-Terminal Pro-B-Type Natriuretic Peptide) >4.9 (odds ratio, 2.40; 95% confidence interval, 1.55-3.71; P<0.0001) and endostatin >4.7 (odds ratio, 2.02; 95% confidence interval, 1.19-3.45; P=0.010), together with age, sex, blood pressure, stroke severity, atrial fibrillation, and hypertension, were included in the model. Predictive accuracy was 80.6%. CONCLUSIONS: The studied biomarkers were not sufficient for an accurate differential diagnosis of stroke in the hyperacute setting. Additional discovery of new biomarkers and improvement on laboratory techniques seem necessary for achieving a molecular diagnosis of stroke.

Plasmatic retinol-binding protein 4 and glial fibrillary acidic protein as biomarkers to differentiate ischemic stroke and intracerebral hemorrhage.

A rapid differentiation of acute ischemic stroke and intracerebral hemorrhage (ICH) is essential for an adequate treatment and to promote a better outcome. Our aim was to identify new plasma biomarkers to differentiate stroke subtypes and to combine their diagnostic ability with other biomarkers already described for this clinical indication. Plasma samples of ischemic stroke patients (36) and ICH patients (10) were screened using a 177 antibodies library, and 11 showed different concentrations among stroke subtypes (p < 0.05), mainly chemokines, growth factors and angiogenic factors. Five proteins were selected for replication in 16 ischemic stroke patients and 16 ICH patients, and retinol-binding protein 4 (RPB4), apolipoprotein B100 and pigment epithelial-derived factor were replicated (p < 0.05). These proteins, together with glial fibrillary acidic protein (GFAP) and receptor for advanced glycation end product, were tested in 38 ischemic stroke and 28 ICH samples. Finally, RBP4 >61 µg/mL and GFAP <0.07 ng/mL showed a specificity of 100% for both subtypes. Moreover, after multivariate logistic regression analysis, RBP4 >48.75 µg/mL (ORadj : 6.09 (1.3-28.57), p = 0.02) and GFAP <0.07 ng/mL (ORadj : 0.03 (0.003-0.31), p = 0.003) resulted in independent predictors of stroke subtype, improving discrimination by 29% (p < 0.0001). Both biomarkers might be useful as diagnostic biomarkers to differentiate ischemic stroke and ICH. A rapid differentiation of ischemic stroke from intracerebral hemorrhage is essential to provide the appropriate treatment. We describe the discovery and subsequent replications of RBP4 and its combination with circulating GFAP as plasmatic biomarkers for hyperacute stroke subtype differentiation. The combination of these biomarkers and others might aid to speed up the discrimination of both stroke subtypes improving the outcome of patients.

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

BACKGROUND AND PURPOSE: Fluorescent molecular peroxidation products (FMPPs) are considered potential markers of molecular oxidative damage and may provoke increased permeability and disruption of the blood-brain barrier. This study aimed to determine the value of FMPPs as a biomarker to predict neurological worsening related to early hemorrhagic transformation. METHODS: Baseline FMPP levels were measured in 186 consecutive acute ischemic stroke patients before tissue plasminogen activator treatment was administered. A serial FMPP profile (baseline before tissue plasminogen activator treatment, and 1, 2, 12, and 24 hours from treatment) was determined in a subset of 100 patients. Computed tomographic scans were performed at admission and repeated at 24 to 48 hours or after neurological worsening occurred. Symptomatic intracranial hemorrhage was defined as blood at any site in the brain associated with neurological deterioration. RESULTS: Patients who worsened had higher median FMPP levels compared with those who did not (59.68 [48.63-85.73] versus 44.87 [36.37-58.90] Uf/mL; P=0.035) at baseline. After logistic regression multivariate analysis, FMPP >48.2 Uf/mL together with age, hypertension, and systolic blood pressure remained baseline predictors of worsening at 48 hours. Moreover, baseline FMPP determination helped to distinguish between patients who worsened and those who did not (Integrated Discrimination Improvement index, 5.7%; P=0.0004). Finally, within patients who had worsened at 48 hours, those with symptomatic intracranial hemorrhage had higher FMPP levels (P=0.038). CONCLUSIONS: FMPPs might be a valuable biomarker of poor early neurological outcome and be related to the appearance of symptomatic intracranial hemorrhage in tissue plasminogen activator-treated patients, one of the most feared neurological complications after thrombolytic treatment of acute ischemic stroke.

Role of beta-defensin 2 and interleukin-4 receptor as stroke outcome biomarkers.

Acute ischemic stroke is a complex disease with huge interindividual evolution variability that makes challenging the prediction of an adverse outcome. Our aim was to study the association of bloodstream signatures to early neurological outcome after stroke, by combining a subpooling of samples strategy with protein array discovery approach. Plasma samples from 36 acute stroke patients (< 4.5 h from onset) were equally pooled within outcome groups: worsening, stability, and improvement (n = 3 pools of four patients each, for each outcome group). These nine pools were screened using a 177 antibodies library, and 35 proteins were found altered regarding outcome classification (p < 0.1). Processes of inflammation, immune response, coagulation, and apoptosis were regulated by these proteins. Ten representative candidates, mainly cytokines and chemokines, were assayed for replication in individual baseline plasma samples from 80 new stroke patients: ß-defensin2, MIP-3b, plasminogen activator inhibitor 1 active, ß-cell-attracting chemokine 1, Exodus-2, interleukin-4 receptor (IL-4R), IL-12p40, leukemia inhibitor factor, MIP-1b, and tumor necrosis factor-related weak inducer of apoptosis. Multivariate logistic regression analysis showed ß-defensin 2 (ORadj 4.87 [1.13-20.91] p = 0.033) and IL-4R (ORadj 3.52 [1.03-12.08] p = 0.045) as independent predictors of worsening at 24 h after adjustment by clinical variables. Both biomarkers improve the prediction by 19% as compared to clinical information, suggesting a potential role for risk stratification in acute thrombolyzed stroke patients. Early neurological deterioration after stroke is not easily predictable. The use of blood biomarkers might help in decision-making processes regarding this complication. By combining a sub-pooling of samples strategy with protein array discovery approach, we have found two new biomarkers: beta-defensin-2 and interleukin-4 receptor. Both biomarkers improve the prediction of poor-outcome over clinical variables in the acute phase of stroke.

Exploratory study of blood biomarkers in patients with post-stroke epilepsy.

INTRODUCTION: In addition to clinical factors, blood-based biomarkers can provide useful information on the risk of developing post-stroke epilepsy (PSE). Our aim was to identify serum biomarkers at stroke onset that could contribute to predicting patients at higher risk of PSE. PATIENTS AND METHODS: From a previous study in which 895 acute stroke patients were followed-up, 51 patients developed PSE. We selected 15 patients with PSE and 15 controls without epilepsy. In a biomarker discovery setting, 5 Olink panels of 96 proteins each, were used to determine protein levels. Biomarkers that were down-regulated and overexpressed in PSE patients, and those that showed the strongest interactions with other proteins were validated using an enzyme-linked immunosorbent assay in samples from 50 PSE patients and 50 controls. A ROC curve analysis was used to evaluate the predictive ability of significant biomarkers to develop PSE. RESULTS: Mean age of the PSE discovery cohort was 68.56 ± 15.1, 40% women and baseline NIHSS 12 [IQR 1-25]. Nine proteins were down-expressed: CASP-8, TNFSF-14, STAMBP, ENRAGE, EDA2R, SIRT2, TGF-alpha, OSM and CLEC1B. VEGFa, CD40 and CCL4 showed greatest interactions with the remaining proteins. In the validation analysis, TNFSF-14 was the single biomarker showing statistically significant downregulated levels in PSE patients (p = 0.006) and it showed a good predictive capability to develop PSE (AUC 0.733, 95% CI 0.601-0.865). DISCUSSION AND CONCLUSION: Protein expression in PSE patients differs from that of non-epileptic stroke patients, suggesting the involvement of several different proteins in post-stroke epileptogenesis. TNFSF-14 emerges as a potential biomarker for predicting PSE.

Biomarkers to improve functional outcome prediction after ischemic stroke: Results from the SICFAIL, STRAWINSKI, and PREDICT studies.

BACKGROUND AND AIMS: Acute ischemic stroke (AIS) outcome prognostication remains challenging despite available prognostic models. We investigated whether a biomarker panel improves the predictive performance of established prognostic scores. METHODS: We investigated the improvement in discrimination, calibration, and overall performance by adding five biomarkers (procalcitonin, copeptin, cortisol, mid-regional pro-atrial natriuretic peptide (MR-proANP), and N-terminal pro-B-type natriuretic peptide (NT-proBNP)) to the Acute Stroke Registry and Analysis of Lausanne (ASTRAL) and age/NIHSS scores using data from two prospective cohort studies (SICFAIL, PREDICT) and one clinical trial (STRAWINSKI). Poor outcome was defined as mRS > 2 at 12 (SICFAIL, derivation dataset) or 3 months (PREDICT/STRAWINSKI, pooled external validation dataset). RESULTS: Among 412 SICFAIL participants (median age 70 years, quartiles 59-78; 63% male; median NIHSS score 3, quartiles 1-5), 29% had a poor outcome. Area under the curve of the ASTRAL and age/NIHSS were 0.76 (95% CI 0.71-0.81) and 0.77 (95% CI 0.73-0.82), respectively. Copeptin (0.79, 95% CI 0.74-0.84), NT-proBNP (0.80, 95% CI 0.76-0.84), and MR-proANP (0.79, 95% CI 0.75-0.84) significantly improved ASTRAL score's discrimination, calibration, and overall performance. Copeptin improved age/NIHSS model's discrimination, copeptin, MR-proANP, and NT-proBNP improved its calibration and overall performance. In the validation dataset (450 patients, median age 73 years, quartiles 66-81; 54% men; median NIHSS score 8, quartiles 3-14), copeptin was independently associated with various definitions of poor outcome and also mortality. Copeptin did not increase model's discrimination but it did improve calibration and overall model performance. DISCUSSION: Copeptin, NT-proBNP, and MR-proANP improved modest but consistently the predictive performance of established prognostic scores in patients with mild AIS. Copeptin was most consistently associated with poor outcome in patients with moderate to severe AIS, although its added prognostic value was less obvious.

Immunological biomarkers improve the accuracy of clinical risk models of infection in the acute phase of ischemic stroke.

UNLABELLED: Infection is an independent risk factor for adverse outcome in stroke patients. The risk of developing an infection in this setting is partly related to a stroke-induced immunodepression, in which a shift to a predominant Th2 (immunosuppressive) phenotype has been postulated to play a major role. Our aim was to study whether clinical variables or changes in plasma cytokine expression can predict poststroke infections. PATIENTS AND METHODS: Medical records of 92 stroke patients were reviewed, and the baseline concentration of cytokines from the Th1/Th2 system was determined. Clinical and serological predictors of incident infections and their prognostic significance were sought by means of univariate and multivariate analysis, and two predictive models for developing an infection were constructed by combining independent predictors (strictly clinical in one, and both clinical and serological in the other) for this outcome. The improvement conferred by the addition of immunological markers to the clinical model was assessed by comparing their respective ROC curves and by improvement (Net Reclassification Index and Integrated Discriminator Improvement) analysis. RESULTS: Nineteen patients (20.7% of the study sample) developed an infection. Ongoing antiplatelet therapy at symptom onset (OR 0.02, 95% CI 0.001-0.23, p = 0.001), diabetes mellitus (OR 9.96, 95% CI 1.32-75.29, p = 0.03), IL-13 level <33 pg/ml (OR 84.16, 95% CI 2.53-2795.18, p = 0.01) and interferon-γ level >8.4 pg/ml (OR 60.17, 95% CI 1.78-2037.23, p = 0.02) were independently associated with the development of infections during hospital admission. The combined regression model predicted infection with an accuracy of 93.4%, an improvement in the predictive capacity of 17% (p < 0.001). Infection was associated with a worse neurological status at hospital discharge (median NIHSS score 11 (6-18) vs. 4 (1-11.5), p = 0.014). CONCLUSIONS: This study shows that bloodstream biomarkers are useful to improve the accuracy of clinical prognostic models for infection in the acute phase of stroke. The clinical predictors of infection in the acute phase of stroke are relatively well established in the medical literature, but further research to identify the optimal combination of biomarkers (possibly inflammatory and stress markers) to be included in a clinically useful model is needed. Such a model could be subsequently used in clinical trials to assess the effect of prophylactic and/or early antibiotic therapy in this setting, a currently controversial issue in this field.

Diesel exhaust particles exposure exacerbates pro-thrombogenic plasma features ex-vivo after cerebral ischemia and accelerates tPA-induced clot-lysis in hypertensive subjects.

The combustion of fossil fuels, mainly by diesel engines, generates Diesel Exhaust Particles (DEP) which are the main source of Particulate Matter (PM), a major air pollutant in urban areas. These particles are a risk factor for stroke with 5.6% of cases attributed to PM exposure. Our aim was to evaluate the effect of DEP exposure on clot formation and lysis in the context of stroke. An ex-vivo clot formation and lysis turbidimetric assay has been conducted in human and mouse plasma samples from ischemic stroke or control subjects exposed to DEP or control conditions. Experimental DEP exposure was achieved by nasal instillation in mice, or by ex-vivo exposure in human plasma. Results show consistent pro-thrombogenic features in plasma after human ischemic stroke and mouse cerebral ischemia (distal MCAo), boosted by the presence of DEP. Otherwise, thrombolysis times were increased after ischemia in chronically exposed mice but not in the DEP exposed group. Finally, subjects living in areas with high PM levels presented accelerated thrombolysis compared to those living in low polluted areas. Overall, our results point at a disbalance of the thrombogenic/lytic system in presence of DEP which could impact on ischemic stroke onset, clot size and thrombolytic treatment.

Blood biomarker changes following therapeutic hypothermia in ischemic stroke.

INTRODUCTION: Therapeutic hypothermia is a promising candidate for stroke treatment although its efficacy has not yet been demonstrated in patients. Changes in blood molecules could act as surrogate markers to evaluate the efficacy and safety of therapeutic cooling. METHODS: Blood samples from 54 patients included in the EuroHYP-1 study (27 treated with hypothermia, and 27 controls) were obtained at baseline, 24 ± 2 h, and 72 ± 4 h. The levels of a panel of 27 biomarkers, including matrix metalloproteinases and cardiac and inflammatory markers, were measured. RESULTS: Metalloproteinase-3 (MMP-3), fatty-acid-binding protein (FABP), and interleukin-8 (IL-8) increased over time in relation to the hypothermia treatment. Statistically significant correlations between the minimum temperature achieved by each patient in the hypothermia group and the MMP-3 level measured at 72 h, FABP level measured at 24 h, and IL-8 levels measured at 24 and 72 h were found. No differential biomarker levels were observed in patients with poor or favorable outcomes according to modified Rankin Scale scores. CONCLUSION: Although the exact roles of MMP3, FABP, and IL-8 in hypothermia-treated stroke patients are not known, further exploration is needed to confirm their roles in brain ischemia.

Lipoprotein-associated phospholipase A(2) activity is associated with large-artery atherosclerotic etiology and recurrent stroke in TIA patients.

BACKGROUND: Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) has emerged as a novel biomarker in cardiovascular diseases due to its ability to predict stroke in population-based studies. We aimed to investigate Lp-PLA(2) levels in transient ischemic attack (TIA) patients and to study their relationship with stroke recurrence. METHODS: Lp-PLA(2) mass and activity were measured by means of the PLAC test with an automated Olympus analyzer and by a colorimetric activity method (diaDexus) in 166 TIA patients and 144 healthy controls. Vascular risk factors and stroke etiology were assessed. Outcome was defined as the presence of recurrent stroke/TIA within 7 and 30 days after the index TIA. Multivariate analyses were performed to identify potential predictors of recurrence. RESULTS: Both Lp-PLA(2) mass and activity (p < 0.05) were higher in TIA than in controls. Several risk factors or previous treatments were associated with Lp-PLA(2) mass and activity level. During follow-up, 20 strokes/TIA (12%) occurred within the first 30 days and the presence of a large-artery atherosclerosis etiology of stroke (HR 3.28, p = 0.011), together with the past medical history of hyperlipidemia (HR 3.68, p = 0.008) and Lp-PLA(2) activity of >207 nmol/ml/min (HR 2.7, p = 0.042) were all significant predictors for recurrent stroke/TIA. CONCLUSIONS: Lp-PLA(2) activity might add significant prognostic information in the early evaluation of TIA patients.

VAP-1/SSAO plasma activity and brain expression in human hemorrhagic stroke.

BACKGROUND: Vascular adhesion protein-1 (VAP-1) is a cell surface and circulating enzyme that belongs to the semicarbazide-sensitive amine oxidase (SSAO) family, which oxidatively deaminates primary amines and is implicated in leukocyte extravasation. Our aim was to investigate the alteration of soluble VAP-1/SSAO activity in plasma samples after acute intracerebral hemorrhage (ICH) and its presence in human ICH brain tissue. METHODS: VAP-1/SSAO activity was determined in plasma of 66 ICH patients and 58 healthy controls. In addition, we assessed the expression of VAP-1/SSAO in postmortem brain tissue from hemorrhagic stroke patients by Western blot and immunohistochemistry. RESULTS: We observed significantly higher levels of plasma VAP-1/SSAO activity in patients with ICH compared to matched elderly controls (p = 0.001). Plasma VAP-1/SSAO activity <2.7 pmol/min·mg and baseline ICH volume <17 ml were independent predictors of neurological improvement after 48 h (OR 6.8, 95% CI 1.14-41.67, p = 0.035, and OR 10.64, 95% CI 1.1-100, p = 0.041, respectively), after adjustment for baseline stroke severity. We also found that membrane-bound VAP-1/SSAO levels were lower in the perihematoma region than in the corresponding contralateral brain areas of patients deceased due to ICH (p = 0.024). CONCLUSIONS: Our data demonstrate that plasma VAP-1/SSAO activity is increased in ICH and predicts neurological outcome, suggesting a possible contribution of the soluble protein in secondary brain damage. Furthermore, anti-VAP-1/SSAO strategies might be a promising approach to prevent neurological worsening following ICH.

Plasma ß-amyloid levels in cerebral amyloid angiopathy-associated hemorrhagic stroke.

BACKGROUND: Cerebral amyloid angiopathy (CAA) is one of the main causes of intracerebral hemorrhage (ICH) in the elderly. OBJECTIVE: To analyze ß-amyloid (Aß) species in plasma in order to uncover biological markers that may contribute to improve the diagnosis of CAA in life. METHODS: We determined the level of Aß(1-40), Aß(N-40), Aß(1-42) and Aß(N-42) in plasma of CAA-related ICH patients (n = 29) and healthy controls (n = 21) using xMAP® technology. Hemorrhages were identified and classified using a CT scan and brain MRI. Patients were clinically classified as probable or possible CAA according to the Boston criteria. RESULTS: We found that plasma full-length Aß(1-42) and truncated fragments Aß(N-42) were higher in probable CAA patients than in controls (p < 0.001 and p = 0.046, respectively), and full-length Aß(1-40) was selectively elevated in probable CAA compared to possible cases (p = 0.015) and controls (p = 0.005). In addition, plasma Aß(N-42) levels were also higher in patients that presented multiple lobar macrohemorrhages compared to patients that had one symptomatic hemorrhagic event (p = 0.022), indicating that a certain degree of CAA severity is necessary to show increased Aß fragments in peripheral circulation. CONCLUSION: Our results suggest that specific Aß fragments in plasma might be considered as potential biomarkers for the diagnosis of CAA.

Blood-biomarkers and devices for atrial fibrillation screening: Lessons learned from the AFRICAT (Atrial Fibrillation Research In CATalonia) study.

BACKGROUND AND OBJECTIVE: AFRICAT is a prospective cohort study intending to develop an atrial fibrillation (AF) screening program through the combination of blood markers, rhythm detection devices, and long-term monitoring in our community. In particular, we aimed to validate the use of NT-proBNP, and identify new blood biomarkers associated with AF. Also, we aimed to compare AF detection using various wearables and long-term Holter monitoring. METHODS: 359 subjects aged 65-75 years with hypertension and diabetes were included in two phases: Phase I (n = 100) and Phase II (n = 259). AF diagnosis was performed by baseline 12-lead ECG, 4 weeks of Holter monitoring (NuuboTM), and/or medical history. An aptamer array including 1310 proteins was measured in the blood of 26 patients. Candidates were selected according to p-value, logFC and biological function to be tested in verification and validation phases. Several screening devices were tested and compared: AliveCor, Watch BP, MyDiagnostick and Fibricheck. RESULTS: AF was present in 34 subjects (9.47%). The aptamer array revealed 41 proteins with differential expression in AF individuals. TIMP-2 and ST-2 were the most promising candidates in the verification analysis, but none of them was further validated. NT-proBNP (log-transformed) (OR = 1.934; p<0.001) was the only independent biomarker to detect AF in the whole cohort. Compared to an ECG, WatchBP had the highest sensitivity (84.6%) and AUC (0.895 [0.780-1]), while MyDiagnostick showed the highest specificity (97.10%). CONCLUSION: The inclusion and monitoring of a cohort of primary care patients for AF detection, together with the testing of biomarkers and screening devices provided useful lessons about AF screening in our community. An AF screening strategy using rhythm detection devices and short monitoring periods among high-risk patients with high NT-proBNP levels could be feasible.