Endogenous granulocyte colony-stimulating factor: a biomarker in acute ischemic stroke

Angiogenesis Biomarkers in Ischemic Stroke Patients

Introduction

Stroke is a global health issue, and ischemic stroke is among the most common strokes affecting many people worldwide. Throughout ischemic stroke, various immune cells counter its effect by releasing cytokines, chemokines, and angiogenic molecules. These molecules can work as potential biomarkers in the diagnosis and monitoring of the progress of ischemic stroke. The current study investigated the use of angiogenic molecules as biomarkers in ischemic stroke patients.

Methods

The samples were obtained from twenty healthy subjects and nineteen patients with ischemic stroke. Multiplex assay was used to measure the serum levels of angiogenic biomarkers, including endoglin, VEGF-A, endothelin-1, G-CSF, and angiopoietin-2. All data were analyzed using an unpaired Student’s t-test. Correlations between measured parameters were made using Pearson correlations.

Results

Angiopoietin-2, VEGF-A, endothelin-1, and endoglin levels in stroke patients were significantly higher compared to healthy controls. Nevertheless, G-CSF level showed a non-significant increase in patients compared to controls. The correlation coefficient of measured angiogenic biomarkers among patients showed significant correlations between endoglin, angiopoietin, VEGF-A, and endothelin-1.

Discussion

The angiogenic factors were significantly increased in patients with ischemic stroke, which may help in the early detection of ischemic stroke and consequently prompt treatment and better prognosis.

Circulating granulocyte colony-stimulating factor and functional outcome after ischemic stroke: an observational study

Objectives: While granulocyte colony-stimulating factor (G-CSF) has shown beneficial effects in experimental ischemic stroke (IS), these effects have not been reproduced clinically. Small-to-medium-sized observational studies have reported varying associations for G-CSF with stroke severity and post-stroke functional outcome, prompting their investigation in a larger study.Methods: Endogenous serum G-CSF (S-GCSF) was measured in the acute phase and after 3 months in patients with IS (N = 435; 36% females; mean age, 57 years) from the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). Stroke severity was scored according to the National Institutes of Health Stroke Scale (NIHSS), and the modified Rankin Scale (mRS) assessed functional outcomes at 3-month and 2-year post-stroke. Correlation and logistic regression analyses with confounder adjustments assessed the relationships.Results: The acute S-GCSF level was 23% higher than at 3-month post-stroke (p < 0.001). Acute G-CSF correlated weakly with stroke severity quintiles (r = 0.12, p = 0.013) and with high-sensitivity C-reactive protein (r = 0.29, p < 0.001). The association between S-GCSF (as quintiles, q) and poor functional outcome at 3 months (mRS 3-6; S-GCSF-q5 vs. S-GCSF-q1, age- and sex-adjusted odds ratio: 4.27, 95% confidence interval: 1.82-9.99; p = 0.001) withstood adjustment for cardiovascular risk factors and stroke subtype, but not additional correction for stroke severity. Post-stroke changes in S-GSCF and absolute 3-month S-GCSF were not associated with 3-month or 2-year functional outcomes.Discussion: Early post-stroke S-GCSF is increased in severe IS and associated with 3-month poor functional outcomes. The change in S-GCSF and the 3-month S-GCSF appear to be less-important, and S-GCSF likely reflects inflammation in large infarctions.

Different changes in granulocyte-colony stimulating factor and its correlation with inflammatory biomarkers in patients after traumatic brain injury

OBJECTIVE

This study analyzed changes in granulocyte-colony stimulating factor (G-CSF) and its correlation with leukocyte and neutrophil counts in patients after traumatic brain injury (TBI).

METHODS

Sixty TBI patients were included retrospectively. The serum levels of G-CSF, tumor necrosis factor-α (TNF-α), and peripheral leukocyte and neutrophil counts at different time points were measured and analyzed, and the 6-month functional outcomes were monitored.

RESULTS

The levels of G-CSF in mild and moderate TBI groups were higher than the control at the first three time points. G-CSF in the severe TBI group increased slowly and peaked at day 7, and was only significantly different from the control at day 7 and 14. The leukocyte and neutrophil counts of the mild group gradually decreased, but a second increase after day 4 was observed in the severe group. The cell counts were higher in the severe group compared to other groups. A positive correlation between G-CSF and leukocyte and neutrophil counts was observed in the severe group at day 1. G-CSF positively correlated with TNF-α in the severe group at day 4 and 7. In severe patients with a good outcome, G-CSF level at day 7 was significantly higher than those with a poor outcome.

CONCLUSION

The G-CSF levels in the severe TBI group exhibited a different pattern from those in the mild and moderate TBI groups, and these levels positively correlated with inflammatory biomarkers. Higher G-CSF levels in severe TBI at day 7 indicated a good outcome at 6 months.

Neurovascular unit crosstalk: Pericytes and astrocytes modify cytokine secretion patterns of brain endothelial cells

Crosstalk among brain endothelial cells (BECs), pericytes, and astrocytes occurs by way of soluble factors, including cytokines. Here, we studied cytokine secretion from both mouse BEC monocultures and tri-cultured with pericytes and astrocytes. Four cytokines were constitutively secreted by BEC monolayers, 12 by LPS-stimulated BECs, 10 by tri-cultures, and 14 by LPS-stimulated tri-cultures. Cytokine levels were generally higher with either LPS stimulation or tri-culture when compared to monocultures and highest in tri-cultures stimulated by LPS. LPS-stimulated secretions fell into eight patterns as categorized by the polarization of cytokine secretions. To determine the cellular origin of cytokine increases in tri-cultures, we cultured mouse BECs with human pericytes and astrocytes and measured cytokines in species-specific assays. Thus, cytokines detected in the human immunoassay were from pericytes/astrocytes and those detected in the mouse immunoassay were from BECs. Several unique patterns were thus found. For example, TNF-alpha was only of pericyte/astrocyte origin; granulocyte colony-stimulating factor was only of BEC origin; IL-6, MCP-1, and GM-CSF of astrocyte/pericyte origin were found in both the luminal and abluminal chambers, suggesting the presence of brain-to-blood transporters. We conclude that crosstalk influences cytokine secretion under constitutive and stimulated conditions from both BECs and pericytes/astrocytes.

Blood Biomarkers for Evaluation of Perinatal Encephalopathy

Recent research in identification of brain injury after trauma shows many possible blood biomarkers that may help identify the fetus and neonate with encephalopathy. Traumatic brain injury shares many common features with perinatal hypoxic-ischemic encephalopathy. Trauma has a hypoxic component, and one of the 1st physiologic consequences of moderate-severe traumatic brain injury is apnea. Trauma and hypoxia-ischemia initiate an excitotoxic cascade and free radical injury followed by the inflammatory cascade, producing injury in neurons, glial cells and white matter. Increased excitatory amino acids, lipid peroxidation products, and alteration in microRNAs and inflammatory markers are common to both traumatic brain injury and perinatal encephalopathy. The blood-brain barrier is disrupted in both leading to egress of substances normally only found in the central nervous system. Brain exosomes may represent ideal biomarker containers, as RNA and protein transported within the vesicles are protected from enzymatic degradation. Evaluation of fetal or neonatal brain derived exosomes that cross the blood-brain barrier and circulate peripherally has been referred to as the "liquid brain biopsy." A multiplex of serum biomarkers could improve upon the current imprecise methods of identifying fetal and neonatal brain injury such as fetal heart rate abnormalities, meconium, cord gases at delivery, and Apgar scores. Quantitative biomarker measurements of perinatal brain injury and recovery could lead to operative delivery only in the presence of significant fetal risk, triage to appropriate therapy after birth and measure the effectiveness of treatment.

Assessing blood granulocyte colony-stimulating factor as a potential biomarker of acute traumatic brain injury in mice and humans

Previous work has found that serum G-CSF was acutely elevated in mice 24h but not one week after controlled cortical impact (CCI). The purpose of this study was to investigate whether blood G-CSF correlates with the elevated brain cytokines in mice after CCI and also if it correlates with traumatic brain injury (TBI) in humans. Here, we found in mice undergoing CCI, a procedure that induces direct injury to the brain, that serum G-CSF correlated directly or indirectly with several brain cytokines, indicating it is a useful marker for the neuroinflammation of TBI. A pilot study in humans (phase I, n=19) confirmed that plasma G-CSF is acutely elevated on day 1 (p<0.001) of TBI and has returned to baseline by one week. In a second human sample (phase II) (n=80), we found plasma G-CSF peaks about 12h after arriving in the emergency department (41.6+/-5.4 pg/ml). Aging was weakly associated (p<0.05) with a less robust elevation in serum G-CSF, but there was no difference with gender. ISS, a measure of total severity of injury, correlated with the degree of elevation in serum G-CSF (r=.419; p<0.05), but severity of head injury (via AIS) did not. The latter may have been because of the statistically narrow range of head injuries among our cases and the high number of cases diagnosed with closed head injury (a non-codable diagnosis). In conclusion, plasma G-CSF may be a useful biomarker of TBI, correlating with neuroinflammation in the animal model and in the human studies with time since injury and total severity of injury. As such, it may be useful in determining whether TBI has occurred within the last 24h.

Autophagy biomarkers in CSF correlates with infarct size, clinical severity and neurological outcome in AIS patients

Background

Autophagy is demonstrated to be involved in acute ischemic stroke(AIS), which, however, is confined to cells and/or animals levels. The aim of this study was to determine two autophagy biomarkers, Beclin1 and LC3B, in cerebrospinal fluid (CSF) and serum of patients with AIS, and to evaluate a possible correlation between levels of Beclin1 and LC3B and severity of neurological deficit and clinical outcome of stroke patients.

Methods

Levels of Beclin1 and LC3B were quantified by ELISA in CSF and serum collected from 37 AIS patients and 21 controls. The clinical severity at stroke onset was determined by the National Institute of Health Stroke Scale (NIHSS) and the neurological outcome was determined by the Modified Rankin Scale (mRs) and the improvement in NIHSS between stroke onset and 3 months later. Associations between autophagy biomarkers and infarct volume, NIHSS and mRs were assessed using Pearson analysis.

Results

The levels of Beclin1 and LC3B were increased both in CSF and serum of AIS patients relative to controls. In CSF, they were positively correlated with infarct volume and NIHSS scores, and negatively correlated with mRs scores, but no significant association was observed in serum. Moreover, AIS patients with higher levels of Beclin1 and LC3B in CSF had significantly higher improvement in NIHSS.

Conclusion

CSF and serum levels of autophagy biomarkers are altered in AIS patients. CSF levels of autophagy biomarkers are associated with infarct volume, clinical severity of and neurological outcome.

Complement component 3 inhibition by an antioxidant is neuroprotective after cerebral ischemia and reperfusion in mice

Oxidative stress after stroke is associated with the inflammatory system activation in the brain. The complement cascade, especially the degradation products of complement component 3, is a key inflammatory mediator of cerebral ischemia. We have shown that pro-inflammatory complement component 3 is increased by oxidative stress after ischemic stroke in mice using DNA array. In this study, we investigated whether up-regulation of complement component 3 is directly related to oxidative stress after transient focal cerebral ischemia in mice and oxygen-glucose deprivation in brain cells. Persistent up-regulation of complement component 3 expression was reduced in copper/zinc-superoxide dismutase transgenic mice, and manganese-superoxide dismutase knock-out mice showed highly increased complement component 3 levels after transient focal cerebral ischemia. Antioxidant N-tert-butyl-α-phenylnitrone treatment suppressed complement component 3 expression after transient focal cerebral ischemia. Accumulation of complement component 3 in neurons and microglia was decreased by N-tert-butyl-α-phenylnitrone, which reduced infarct volume and impaired neurological deficiency after cerebral ischemia and reperfusion in mice. Small interfering RNA specific for complement component 3 transfection showed a significant increase in brain cells viability after oxygen-glucose deprivation. Our study suggests that the neuroprotective effect of antioxidants through complement component 3 suppression is a new strategy for potential therapeutic approaches in stroke.