Serum Levels of Thioredoxin Are Associated with Stroke Risk, Severity, and Lesion Volumes

The Importance of Thioredoxin-1 in Health and Disease

Thioredoxin-1 (Trx-1) is a multifunctional protein ubiquitously found in the human body. Trx-1 plays an important role in various cellular functions such as maintenance of redox homeostasis, proliferation, and DNA synthesis, but also modulation of transcription factors and control of cell death. Thus, Trx-1 is one of the most important proteins for proper cell and organ function. Therefore, modulation of Trx gene expression or modulation of Trx activity by various mechanisms, including post-translational modifications or protein-protein interactions, could cause a transition from the physiological state of cells and organs to various pathologies such as cancer, and neurodegenerative and cardiovascular diseases. In this review, we not only discuss the current knowledge of Trx in health and disease, but also highlight its potential function as a biomarker.

Advances in the Functions of Thioredoxin System in Central Nervous System Diseases

Significance: The thioredoxin system comprises thioredoxin (Trx), thioredoxin reductase (TrxR), and nicotinamide adenine dinucleotide phosphate, besides an endogenous Trx inhibitor, the thioredoxin-interacting protein (TXNIP). The Trx system plays critical roles in maintaining the redox homeostasis in the central nervous system (CNS), in which oxidative stress damage is prone to occurrence due to its high-energy demand. Recent Advances: Increasing studies have demonstrated that the expression or activity of Trx/TrxR is usually decreased and that TXNIP expression is increased in patients with CNS diseases, including neurodegenerative diseases, cerebral ischemia, traumatic brain injury, and depression, as well as in their cellular and animal models. The compromise of Trx/TrxR enhances the susceptibility of neurons to related pathological state. Increased TXNIP not only enhances the inhibition of Trx activity, but also activates the NOD-like receptor protein 3 inflammasome, resulting in neuroinflammation in the brain. Critical Issues: In this review, we highlight the sources of oxidative stress in the CNS. The expression and function of the Trx system are summarized in different CNS diseases. This review also mentions that some inducers of Trx show neuroprotection in CNS diseases. Future Directions: Accumulating evidence has demonstrated the important roles of the Trx system in CNS diseases, suggesting that the Trx system may be a promising therapeutic target for CNS diseases. Further study should aim to develop the most effective inducers of Trx and specific inhibitors of TXNIP and to apply them in the clinical trials for the treatment of CNS diseases. Antioxid. Redox Signal. 38, 425-441.

Changing Perspectives from Oxidative Stress to Redox Signaling-Extracellular Redox Control in Translational Medicine

Extensive research has changed the understanding of oxidative stress that has been linked to every major disease. Today we distinguish oxidative eu- and distress, acknowledging that redox modifications are crucial for signal transduction in the form of specific thiol switches. Long underestimated, reactive species and redox proteins of the Thioredoxin (Trx) family are indeed essential for physiological processes. Moreover, extracellular redox proteins, low molecular weight thiols and thiol switches affect signal transduction and cell–cell communication. Here, we highlight the impact of extracellular redox regulation for health, intermediate pathophenotypes and disease. Of note, recent advances allow the analysis of redox changes in body fluids without using invasive and expensive techniques. With this new knowledge in redox biochemistry, translational strategies can lead to innovative new preventive and diagnostic tools and treatments in life sciences and medicine.

Fast Imaging of Mitochondrial Thioredoxin Reductase Using a Styrylpyridinium-Based Two-Photon Ratiometric Fluorescent Probe

Thioredoxin reductase (TrxR) is a pivotal antioxidant enzyme, but there remains a challenge for its fast imaging. This work describes the combination of a hydroxyl styrylpyridinium scaffold as the push-pull fluorophore with a carbonate-bridged 1,2-dithiolane unit as the reaction site to develop a fast mitochondrial TrxR2 probe, DSMP. It manifested a plethora of excellent properties including a rapid specific response (12 min), large Stokes shift (170 nm), ratiometric two-photon imaging, favorable binding with TrxR (K_m = 12.5 ± 0.2 μM), and the ability to cross the blood-brain barrier. With the aid of DSMP, we visualized the increased mitochondrial TrxR2 activity in cancer cells compared to normal cells. This offers the direct imaging evidence of the connection between the increased TrxR2 activity and the development of cancer. Additionally, the probe allowed the visualization of the loss in TrxR2 activity in a cellular Parkinson's disease model and, more importantly, in mouse brain tissues of a middle cerebral artery occlusion model for ischemic stroke.

Recent Advances in Fluorescent Probes for Flavinase Activity: Design and Applications

Flavinases, including monoamine oxidase (MAO-A/MAO-B), quinone oxidoreductase (NQO1), thioredoxin reductase (TrxR), nitroreductase (NTR) and so on, are important redox enzymes in organisms. They are considered as biomarkers of cell energy metabolism and cell vitality. Importantly, their aberrant expression is related to various disease processes. Therefore, the accurate measurement of flavinase is useful for the early diagnosis of diseases, which has aroused great concern in the scientific community. Various methods are also available for the detection of flavinases, fluorescence probes are considered to be one of the best detection methods due to their easy and accurate sensing capability. This review aims to introduce the advances in the design and application of flavinase probes in the last five years. This study focuses on analyzing the design strategies and reaction mechanisms of flavinases fluorescent probes and discusses the current challenges, which will further advance the development of diagnostic and therapeutic approaches for flavinase-related diseases.

Elevated serum 4HNE plus decreased serum thioredoxin: Unique feature and implications for acute exacerbation of chronic obstructive pulmonary disease

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a global problem with high mortality. Its pathogenesis is not fully understood. To reveal new serum feature of AECOPD and their potential implications, we have analyzed 180 serum samples, and found that in the serum of AECOPD patients, 4-hydroxy-2-nonenal (4HNE)-protein adducts are dynamically increased as partial pressure of oxygen (PaO2) drops, which is accompanied by progressively decreasing thioredoxin reductase (TrxR1) and thioredoxin (Trx1), as compared with those of healthy people. This phenomenon is unique, because acute hypoxia patients have 1.1-fold or 1.7-fold higher serum TrxR1 or Trx1 activity, respectively, than healthy people, in keeping with low 4HNE level. Moreover, serum 4HNE-protein adducts may form disulfide-linked complexes with high-molecular-weight, the amount of which is significantly increased during AECOPD. Serum 4HNE-protein adducts include 4HNE-Trx1 adduct and 4HNE-TrxR1 adduct, but only the former is significantly increased during AECOPD. Through cell biology, biochemistry and proteomics methods, we have demonstrated that extracellular 4HNE and 4HNE-Trx1 adduct affect human bronchial epithelial cells via different mechanisms. 4HNE-Trx1 adduct may significantly alter the expression of proteins involved mainly in RNA metabolism, but it has no effect on TrxR1/Trx1 expression and cell viability. On the other hand, low levels of 4HNE promote TrxR1/Trx1 expression and cell viability, while high levels of 4HNE inhibit TrxR1/Trx1 expression and cell viability, during which Trx1, at least in part, mediate the 4HNE action. Our data suggest that increasing serum 4HNE and decreasing serum Trx1 in AECOPD patients are closely related to the pathological processes of the disease. This finding also provides a new basis for AECOPD patients to use antioxidant drugs.

Acute ischemic stroke biomarkers: a new era with diagnostic promise?

Stroke is considered as the first cause of neurological dysfunction and second cause of death worldwide. Recombinant tissue plasminogen activator is the only chemical treatment for ischemic stroke approved by the US Food and Drug Administration. It was the only standard of care for a long time with a very narrow therapeutic window, which usually ranges from 3 to 4.5 h of stroke onset; until 2015, when multiple trials demonstrated the benefit of mechanical thrombectomy during the first 6 h. In addition, recent trials showed that mechanical thrombectomy can be beneficial up to 24 h if the patients meet certain criteria including the presence of magnetic resonance imaging/computed tomography perfusion mismatch, which allows better selectivity and higher recruitment of eligible stroke patients. However, magnetic resonance imaging/computed tomography perfusion is not available in all stroke centers. Hence, physicians need other easy and available diagnostic tools to select stroke patients eligible for mechanical thrombectomy. Moreover, stroke management is still challenging for physicians, particularly those dealing with patients with "wake-up" stroke. The resulting brain tissue damage of ischemic stroke and the subsequent pathological processes are mediated by multiple molecular pathways that are modulated by inflammatory markers and post-transcriptional activity. A considerable number of published works suggest the role of inflammatory and cardiac brain-derived biomarkers (serum matrix metalloproteinase, thioredoxin, neuronal and glial markers, and troponin proteins) as well as different biomarkers including the emerging roles of microRNAs. In this review, we assess the accumulating evidence regarding the current status of acute ischemic stroke diagnostic biomarkers that could guide physicians for better management of stroke patients. Our review could give an insight into the roles of the different emerging markers and microRNAs that can be of high diagnostic value in patients with stroke. In fact, the field of stroke research, similar to the field of traumatic brain injury, is in immense need for novel biomarkers that can stratify diagnosis, prognosis, and therapy.

Biomarkers of Unfavorable Outcome in Acute Ischemic Stroke Patients with Successful Recanalization by Endovascular Thrombectomy

<b><i>Background:</i></b> We aimed to identify plasma markers of unfavorable outcomes for patients with acute ischemic stroke (AIS) after recanalization by endovascular thrombectomy (EVT). <b><i>Methods:</i></b> From November 2017 to May 2019, we prospectively collected 61 AIS patients due to anterior large vessel occlusion who achieved recanalization by EVT. Plasma samples were obtained between 18 and 24 h after recanalization. Unfavorable outcomes included futile recanalization at 90 days and overall early complications within 7 days after EVT. <b><i>Results:</i></b> After adjustment for age and initial National Institute of Health Stroke Scale (NIHSS), matrix metalloproteinase-9 (MMP-9), tenascin-C, thioredoxin, ADAMTS13, and gelsolin were independently associated with both futile recanalization and overall early complications significantly (all <i>p</i> &#x3c; 0.05), while C-reactive protein (CRP) was independently associated with overall early complications (<i>p</i> = 0.031) but at the limit of significance for futile recanalization (<i>p</i> = 0.051). The baseline clinical model (BCM) (including age and initial NIHSS) demonstrated discriminating ability to indicate futile recanalization (area under the curve [AUC] 0.807, 95% confidence interval [CI] 0.693–0.921) and overall early complications (AUC 0.749, 95% CI 0.611–0.887). BCM+MMP-9+thioredoxin enhanced discrimination (AUC 0.908, 95% CI 0.839–0.978, <i>p</i> = 0.043) and reclassification (net reclassification improvement [NRI] 67.2%, <i>p</i> &#x3c; 0.001) to indicate futile recanalization. With respect to overall early complications, BCM+MMP-9+tenascin-C, BCM+MMP-9+CRP, BCM+MMP-9+ADAMTS13, BCM+tenascin-C+ADAMTS13, and BCM+CRP+ADAMTS13, all improved discrimination (AUC [95% CI]: 0.868 [0.766–0.970], 0.882 [0.773–0.990], 0.886 [0.788–0.984], 0.880 [0.783–0.977], and 0.863 [0.764–0.962], respectively, all <i>p</i> &#x3c; 0.05 by the DeLong method) and reclassification (NRI 59.1%, 71.8%, 51.1%, 67.4%, and 38.3%, respectively, all <i>p</i> &#x3c; 0.05). <b><i>Conclusions:</i></b> The increased levels of MMP-9, tenascin-C, CRP, thioredoxin, and decreased levels of ADAMTS13 and gelsolin were independent predictors of futile recanalization in AIS patients after recanalization by EVT.

Analytical and clinical validation of rapid chemiluminescence enzyme immunoassay for urinary thioredoxin, an oxidative stress-dependent early biomarker of acute kidney injury

BACKGROUND

Oxidative stress is now recognized to be an important therapeutic target in kidney diseases. However, there are currently no biomarkers that can be used clinically to diagnose renal oxidative stress.

METHODS

A rapid assay system for urinary thioredoxin 1, an oxidative stress-dependent biomarker of acute kidney injury (AKI), was developed as a chemiluminescence enzyme immunoassay and validated analytically and clinically.

RESULTS

Analytic evaluation revealed that hemolytic hemoglobin caused measurements to be abnormally high, above the detectable range. However, urine sediment containing red blood cells did not affect the measurements. Assays using our proposed chemiluminescence enzyme immunoassay were completed within as little as 6 min, whereas a conventional ELISA > 4 h. Aciduria <pH 6.0 led to a significant underestimation of thioredoxin 1 concentrations. However, the effects of aciduria were completely reversible with use of a buffer developed for pH adjustment. Urinary thioredoxin 1 was increased in patients with AKI, but was unaffected by extrarenal oxidative stress diseases, including hypoxemia and myocardial infarction, or by chronic kidney disease in which serum creatinine concentrations were comparable.

CONCLUSIONS

These results suggest that the chemiluminescent enzyme immunoassay system for urinary thioredoxin 1 enables rapid and specific diagnosis of AKI associated with oxidative stress.

Loss of thioredoxin reductase function in a mouse stroke model disclosed by a two-photon fluorescent probe

The first two-photon fluorescent probe (TP-TRFS) is reported, and it was successfully used in vivo.

Blood biomarkers for stroke: the role of thioredoxin in diagnosis and prognosis of acute ischemic stroke

Background

Oxidative stress plays a crucial role in the pathophysiology of acute ischemic stroke. Thioredoxin exists and released from cells during inflammation and oxidative stress and was recognized as an oxidative-stress marker.

Objective

The objective of this study was to assess the role of thioredoxin as an oxidative stress biomarker in diagnosis and prognosis of acute ischemic stroke in a sample of patients recruited from Beni-Suef Governorate, north Upper Egypt.

Methods

A case control study included 100 subjects; 50 patients with first-ever acute ischemic stroke presented within 24 h from the onset and 50 healthy volunteers as a control. Clinical, functional, and radiological evaluation was done for the patients, and all patients and control were subjected to routine laboratory tests and assessment of serum level of thioredoxin by solid-phase sandwich enzyme-linked immunosorbent assay.

Results

Thioredoxin was significantly higher in acute stroke patients compared to control group (p value = 0.001). Thioredoxin level was significantly higher in hypertensive patients (p value = 0.007), patients who had carotid stenosis ≥50% (p value = 0.001), patients with poor outcome (p value = 0.009), and in patients with cardio-embolic stroke (p value = 0.001).

Significant positive correlation was found between thioredoxin level and volume of infarction (r = 0.501 and p = 0.001), stroke severity at presentation (r = 0.503 and p = 0.021) and clinical outcome after 3 months (r = 0.551 and p value = 0.001).

Conclusion

Thioredoxin as a marker of oxidative stress can be used as a new diagnostic and prognostic blood biomarker for stroke.

Prognostic value of serum thioredoxin levels in ischemic stroke

OBJECTIVES

Thioredoxin (Trx) is one of significant antioxidative molecules to diminish oxidative stress. Current evidence suggests that Trx is a potent antioxidant with cytoprotective functions. The aim of our study was to investigate specifically the association between serum Trx levels and acute ischemic stroke (AIS) patients.

METHODS

198 AIS patients and 75 controls were enrolled to the study. Serum Trx levels were measured using an enzyme-linked immunosorbent assay (ELISA). Stroke severity was assessed with the National Institutes of Health Stroke Scale (NIHSS) score on admission. Clinical endpoint was functional outcome measured by Barthel Index (BI) 3 months after admission. Multivariate binary logistic regression analyses were performed to identify predictors.

RESULTS

We found that serum Trx levels were significantly increased in patients as compared to controls. Serum Trx was an independent biomarker to predict ischemic stroke (OR, 1.264; 95% CI, 1.04-1.537; P = 0.019). In addition, there was a negative correlation between NIHSS score at admission and serum Trx levels in cardioembolic stroke patients (r = -0.422; P = 0.013). Furthermore, higher serum Trx levels in AIS patients were associated with favorable functional outcome. Serum Trx was an independent predictor for the functional outcome (OR, 0.862; 95% CI, 0.75-0.991; P = 0.037).

CONCLUSIONS

Serum Trx might be as a biomarker of cardioembolic stroke severity. Increased serum Trx levels could be a useful tool to predict good prognosis in patients with AIS.

Serum IL-33 Is a Novel Diagnostic and Prognostic Biomarker in Acute Ischemic Stroke

Interleukin-33 (IL-33), a newly recognized IL-1 family member, is expressed in various tissues and cells, and involved in pathogenesis of many human diseases. For example, IL-33 plays a protective role in cardiovascular diseases. However, the role of IL-33 in acute ischemic stroke (AIS) remains unclear. This study aims to investigate whether IL-33 level in AIS patient serum can be used as a potential diagnostic and prognostic marker. The study included two hundred and six patients with first-ever ischemic stroke, who were admitted within 72 hours after stroke onset. The serum level of IL-33 was measured with ELISA and the severity of AIS patients on admission was evaluated based on the National Institutes of Health Stroke Scale (NIHSS) score. The functional outcome at 3 months was determined using the Barthel index (BI). We found that serum IL-33 was significantly higher (P < 0.001) in patients with AIS [57.68 ng/L (IQR, 44.95-76.73)] compared with healthy controls [47.48 ng/L (IQR, 38.67-53.78)]. IL-33 was an independent diagnostic biomarker for AIS with an OR of 1.051 (95%Cl, 1.018-1.085; P=0.002). Serum IL-33 was higher (P < 0.05) in the stroke patients with small cerebral infarction volume compared to AIS patients with large cerebral infarction. In addition, serum IL-33 was also significantly higher (P = 0.001) in the patients with mild stroke, compared to the patients with severe stroke. Furthermore, serum IL-33 level in AIS patients with a worse outcome was higher (P < 0.001) compared to AIS patients with a better outcome. IL-33 was also an independent predictor for the functional outcome with an adjusted OR of 0.932 (95% CI, 0.882-0.986). Our results suggest that the lower level of serum IL-33 is associated with large infarction volume and greater stroke severity in AIS patients. Thus, IL-33 can be used as a novel and independent diagnostic and predicting prognostic marker in AIS.

Thioredoxin as a marker for severity and prognosis of aneurysmal subarachnoid hemorrhage

OBJECTIVE

Circulating levels of thioredoxin (Trx), a potent anti-oxidant that modulates inflammation, cell growth and apoptosis, are increased in various critical care conditions. The purpose of this study was to establish the relationship between serum Trx levels and prognosis of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

An enzyme-linked immunosorbent assay measurement of Trx was performed in serum from 132 patients and 132 healthy volunteers. Clinical outcomes included 6-month mortality and unfavorable outcome (Glasgow outcome scale score of 1-3).

RESULTS

The serum Trx levels were significantly higher in patients than in controls (23.4±12.2 ng/mL vs.8.5±4.0 ng/mL, P<0.001) and had close relation to the World Federation of Neurological Surgeons (WFNS) scores (r=0.461, P<0.001) and modified Fisher scores (r=0.459, P<0.001). Trx was an independent predictor for 6-month mortality (Odds ratio, 1.386; 95% confidence interval, 1.015-2.161; P<0.001) and 6-month unfavorable outcome (Odds ratio, 1.297; 95% confidence interval, 1.012-2.002; P<0.001). Based on receiver operating characteristic curve, TRX had similar prognostic value compared with WFNS scores and modified Fisher scores and also significantly improved their prognostic value for 6-month unfavorable outcome, but not for 6-month mortality.

CONCLUSIONS

Elevated plasma Trx levels are correlated with the severity and poor prognosis, substantializing Trx as a potential prognostic predictive biomarker following aSAH.

Serum CXCL12 Levels as a Novel Predictor of Future Stroke Recurrence in Patients with Acute Ischemic Stroke

Previous studies had shown that CXC chemokine ligand-12 (CXCL12) plays a significant role in animal models of ischemic stroke, but its role in human stroke is unclear. The aim of this study was to test the relationship between elevated serum circulating CXCL12 levels and the 1-year stroke recurrence in Chinese patients with acute ischemic stroke (AIS). All consecutive patients with first-ever acute ischemic stroke from January 2011 to September 2013 were recruited to participate in the study. Serum levels of CXCL12 and National Institute of Health Stroke Scale (NIHSS) were measured at the time of admission. Logistic regression analysis was used to evaluate the stroke recurrence according to serum CXCL12 levels. Receiver operating characteristic (ROC) curve was used to evaluate the accuracy of serum CXCL12 in predicting stroke recurrence. Clinical follow-up was performed at 1 year. In our study, 248 patients finished the 1-year follow-up. At 1-year follow-up, 31 patients had a recurrence ischemic stroke. The median CXCL12 levels were significantly higher in those who sustained a recurrence ischemic stroke compared with those who did not [24.2 ng/mL (IQR 15.4-33.7) vs 6.5 ng/mL (IQR 3.4-10.2); Z = 8.258, P < 0.0001]. In multivariate analysis, there was an increased risk of stroke recurrence associated with serum CXCL12 levels ≥12.15 ng/mL (OR 9.122, 95 % CI 6.103-15.104) after adjusting for above possible confounders. The time to recurrence stroke distribution between patients with baseline CXCL12 levels ≥12.15 ng/mL and those with baseline CXCL12 levels <12.15 ng/mL were significantly different (P < 0.0001, log-rank test). Elevated circulating CXCL12 levels at admission are strongly associated with the future recurrence of ischemic stroke in Chinese patients with AIS. Further studies are warranted to confirm this association and define the role for CXCL12 as a novel predictor biomarker for stroke recurrence.