Growth Differentiation Factor-15 in the Early Diagnosis and Risk Stratification of Patients with Acute Chest Pain

Prospective of Pancreatic Cancer Diagnosis Using Cardiac Sensing

Pancreatic carcinoma (Ca Pancreas) is the third leading cause of cancer-related deaths in the world. The malignancies of the pancreas can be diagnosed with the help of various imaging modalities. An endoscopic ultrasound with a tissue biopsy is so far considered to be the gold standard in terms of the detection of Ca Pancreas, especially for lesions <2 mm. However, other methods, like computed tomography (CT), ultrasound, and magnetic resonance imaging (MRI), are also conventionally used. Moreover, newer techniques, like proteomics, radiomics, metabolomics, and artificial intelligence (AI), are slowly being introduced for diagnosing pancreatic cancer. Regardless, it is still a challenge to diagnose pancreatic carcinoma non-invasively at an early stage due to its delayed presentation. Similarly, this also makes it difficult to demonstrate an association between Ca Pancreas and other vital organs of the body, such as the heart. A number of studies have proven a correlation between the heart and pancreatic cancer. The tumor of the pancreas affects the heart at the physiological, as well as the molecular, level. An overexpression of the SMAD4 gene; a disruption in biomolecules, such as IGF, MAPK, and ApoE; and increased CA19-9 markers are a few of the many factors that are noted to affect cardiovascular systems with pancreatic malignancies. A comprehensive review of this correlation will aid researchers in conducting studies to help establish a definite relation between the two organs and discover ways to use it for the early detection of Ca Pancreas.

Cardiovascular Biomarkers: Lessons of the Past and Prospects for the Future

Cardiovascular diseases (CVDs) are a major healthcare burden on the population worldwide. Early detection of this disease is important in prevention and treatment to minimise morbidity and mortality. Biomarkers are a critical tool to either diagnose, screen, or provide prognostic information for pathological conditions. This review discusses the historical cardiac biomarkers used to detect these conditions, discussing their application and their limitations. Identification of new biomarkers have since replaced these and are now in use in routine clinical practice, but still do not detect all disease. Future cardiac biomarkers are showing promise in early studies, but further studies are required to show their value in improving detection of CVD above the current biomarkers. Additionally, the analytical platforms that would allow them to be adopted in healthcare are yet to be established. There is also the need to identify whether these biomarkers can be used for diagnostic, prognostic, or screening purposes, which will impact their implementation in routine clinical practice.

Growth differentiation factor-15, a novel systemic biomarker of oxidative stress, inflammation, and cellular aging: Potential role in cardiovascular diseases

Growth differentiation factor-15 (GDF-15) is a cytokine upregulated in multiple pathological conditions where oxidative stress, endothelial dysfunction, tissue aging, and chronic inflammation are the hallmarks. GDF-15 has many sources of production, including cardiac and vascular myocytes, endothelial cells, adipocytes and macrophages in response to metabolic stress, oncogenic transformation and the burden of proinflammatory cytokines or reactive oxygen species. Although the main sources of GDF-15 are extracardiac tissues, it has been shown to be elevated in many cardiac disorders. In experimental models of heart disease, GDF-15 release is induced after an ischemic insult and in pressure overload scenarios. Likewise, in recent years, an increasing body of evidence has emerged linking GDF-15 to the risk of mortality in acute coronary syndromes, atrial fibrillation and heart failure. Additionally, GDF-15 has been shown to add prognostic information beyond other conventional biomarkers such as natriuretic peptides and cardiac troponins. Further studies are needed to assess whether the incorporation of GDF-15 into clinical practice can improve cardiovascular outcomes.

Biomarkers of acute myocardial infarction: diagnostic and prognostic value. Part 2 (Literature review)

In the second part of the review, we continue the discussion of biomarkers that have a diagnostic and prognostic significance in acute myocardial infarction (AMI). The study of the AMI pathophysiology through the experimental and clinical research contributes to the discovery of new regulatory molecules and pathogenetic mechanisms underlying AMI. At the same time, many molecules involved in the pathogenesis of AMI can be used as effective biomarkers for the diagnosis and prediction of AMI. This article discusses in detail the diagnostic and prognostic value of inflammatory biomarkers of AMI (C-reactive protein, interleukin-6, tumor necrosis factor-alpha, myeloperoxidase, matrix metalloproteinases, soluble form of CD40 ligand, procalcitonin, placental growth factor) and a number of recently discovered new biomarkers of AMI (microribonucleic acids, galectin-3, stimulating growth factor expressed by gene 2, growth differentiation factor 15, proprotein convertase of subtilisin-kexin type 9).

Growth differentiation factor-15 and its role in diabetes and cardiovascular disease

Growth differentiation factor-15 (GDF-15) is cytokine involved in the regulation of multiple systems. Because it has regularly been shown to be increased in cardiovascular disease (CVD) and diabetes, it has been suggested that GDF-15 could be used as a biomarker for these diseases and their severity. However, several studies have demonstrated that GDF-15 has a protective role in regulation of inflammation, endothelial cell function, insulin sensitivity, weight gain, and is cardioprotective in myocardial infarction (MI). While GDF-15 has been implicated in the pathophysiology of many conditions including cancer, this review focuses on the potential functions of GDF-15 and signaling pathways implicated in its role regulating metabolism, insulin sensitivity, and the cardiovascular system.

Post-Myocardial Infarction Ventricular Remodeling Biomarkers-The Key Link between Pathophysiology and Clinic

Studies in recent years have shown increased interest in developing new methods of evaluation, but also in limiting post infarction ventricular remodeling, hoping to improve ventricular function and the further evolution of the patient. This is the point where biomarkers have proven effective in early detection of remodeling phenomena. There are six main processes that promote the remodeling and each of them has specific biomarkers that can be used in predicting the evolution (myocardial necrosis, neurohormonal activation, inflammatory reaction, hypertrophy and fibrosis, apoptosis, mixed processes). Some of the biomarkers such as creatine kinase-myocardial band (CK-MB), troponin, and N-terminal-pro type B natriuretic peptide (NT-proBNP) were so convincing that they immediately found their place in the post infarction patient evaluation protocol. Others that are related to more complex processes such as inflammatory biomarkers, atheroma plaque destabilization biomarkers, and microRNA are still being studied, but the results so far are promising. This article aims to review the markers used so far, but also the existing data on new markers that could be considered, taking into consideration the most important studies that have been conducted so far.

Growth Differentiation Factor-15 as a Potent Predictor of Long-Term Mortality among Subjects with Osteoarthritis

Background: Subjects with osteoarthritis (OA) are at increased risk for cardiovascular (CV) and all-cause mortality. Whether biomarkers improve outcome prediction in these patients remains to be elucidated. We investigated the association between growth differentiation factor 15 (GDF-15), a novel stress-responsive cytokine, and long-term all-cause mortality among OA patients. Methods: Within the Ulm Osteoarthritis Study, GDF-15 has been measured in the serum of 636 subjects, who underwent hip or knee arthroplasty between 1995 and 1996 (median age 65 years). Results: During a median follow-up of 19.7 years, a total of 402 deaths occurred. GDF-15 was inversely associated with walking distance. Compared to the bottom quartile (Q), subjects within the top quartile of GDF-15 demonstrated a 2.69-fold increased risk of dying (hazard ratio (HR) (95% confidence interval (CI)) 2.69 (1.82–3.96) adjusted for age, sex, BMI, smoking status, localization of OA, diabetes, maximum walking distance, total cholesterol, and cystatin C. Further adjustment for NT-proBNP, troponin I, and hs-C-reactive protein did not change the results appreciably (HR (95%CI) 1.56 (1.07–2.28); 1.75 (1.21–2.55); 2.32 (1.55–3.47) for Q2, Q3, and Q4 respectively, p for trend < 0.001). Conclusions: In subjects with OA, GDF-15 represents a potent predictor of decreased survival over >20 years, independently of conventional CV risk factors, renal, cardiac, and inflammatory biomarkers as well as walking disability, previously associated with increased mortality and lower extremity OA.

GDF15: A Hormone Conveying Somatic Distress to the Brain

GDF15 has recently gained scientific and translational prominence with the discovery that its receptor is a GFRAL-RET heterodimer of which GFRAL is expressed solely in the hindbrain. Activation of this receptor results in reduced food intake and loss of body weight and is perceived and recalled by animals as aversive. This information encourages a revised interpretation of the large body of previous research on the protein. GDF15 can be secreted by a wide variety of cell types in response to a broad range of stressors. We propose that central sensing of GDF15 via GFRAL-RET activation results in behaviors that facilitate the reduction of exposure to a noxious stimulus. The human trophoblast appears to have hijacked this signal, producing large amounts of GDF15 from early pregnancy. We speculate that this encourages avoidance of potential teratogens in pregnancy. Circulating GDF15 levels are elevated in a range of human disease states, including various forms of cachexia, and GDF15-GFRAL antagonism is emerging as a therapeutic strategy for anorexia/cachexia syndromes. Metformin elevates circulating GDF15 chronically in humans and the weight loss caused by this drug appears to be dependent on the rise in GDF15. This supports the concept that chronic activation of the GDF15-GFRAL axis has efficacy as an antiobesity agent. In this review, we examine the science of GDF15 since its identification in 1997 with our interpretation of this body of work now being assisted by a clear understanding of its highly selective central site of action.

GDF-15 in Pulmonary and Critical Care Medicine

GDF-15 (growth differentiation factor 15) acts both as a stress-induced cytokine with diverse actions at different body sites and as a cell-autonomous regulator linked to cellular senescence and apoptosis. For multiple reasons, this divergent transforming growth factor-β molecular superfamily member should be better known to pulmonary researchers and clinicians. In ambulatory individuals, GDF-15 concentrations in peripheral blood are an established predictive biomarker of all-cause mortality and of adverse cardiovascular events. Concentrations upon admission of critically ill patients (without or with sepsis) correlate with organ dysfunction and independently predict short- and long-term mortality risk. GDF-15 is a major downstream mediator of p53 activation, but it can also be induced independently of p53, notably by nonsteroidal antiinflammatory agents. GDF-15 blood concentrations are markedly elevated in adults and children with pulmonary hypertension. Concentrations are also increased in chronic obstructive pulmonary disease, in which they contribute to mucus hypersecretion, airway epithelial cell senescence, and impaired antiviral defenses, which together with murine data support a role for GDF-15 in chronic obstructive pulmonary disease pathogenesis and progression. This review summarizes biological and clinical data on GDF-15 relevant to pulmonary and critical care medicine. We highlight the recent discovery of a central nervous system receptor for GDF-15, GFRAL (glial cell line-derived neurotrophic factor family receptor-α-like), an important advance with potential for novel treatments for obesity and cachexia. We also describe limitations and controversies in the existing literature, and we delineate research questions that must be addressed to determine whether GDF-15 can be therapeutically manipulated in other clinical settings.

Growth Differentiation Factor-15 (GDF-15) Is Associated With Mortality in Ischemic Stroke Patients Treated With Acute Revascularization Therapy

Background and Aims: Growth differentiation factor-15 (GDF-15) has been identified as a robust marker of developing cardiovascular disease, however, little is currently known about its prognostic value in stroke patients. In a context of growing interest to discover new biomarkers in stroke, we aimed to assess the association between circulating GDF-15 levels and three-month mortality in ischemic stroke patients treated with acute revascularization therapy.

Methods: 173 patients hospitalized for acute ischemic stroke and treated with either intravenous thrombolysis (n = 99, 57.2%), mechanical thrombectomy (n = 41, 23.4%) or combined therapy (n = 33, 19.1%) were prospectively included. Baseline clinical and biological characteristics were recorded. Plasma GDF-15 levels were measured at admission (D0), and at 24 h, 3 and 7 days. Clinical severity was assessed with the National Institutes of Health Stroke Scale (NIHSS) score, and vital status was obtained 3 months after the stroke.

Results: At 3 months post-stroke, 32 patients (18.5%) had died. The deceased patients had higher D0 plasma GDF-15 levels (median [IQR]: 2,777 [1,769–5,446] vs. 1,460 [965–2,079] pg/mL, P < 0.001). In multivariable logistic regression analysis, D0 GDF-15 levels in the third tertile of the distribution were independently associated with mortality at 3 months (OR = 3.71; 95% CI: 1.09–12.6, P = 0.036), even after adjustment for confounding variables including clinical severity.

Conclusions: Our data show for the first time that GDF-15 plasma concentration at admission is independently associated with 3-month mortality in ischemic stroke patients treated with acute revascularization therapy. The pathophysiological mechanisms that could explain this association warrant further study.

Growth differentiation factor-15 and all-cause mortality in patients with suspected myocardial infarction

BACKGROUND

To assess the prognostic performance of Growth differentiation factor-15 (GDF-15) concentrations in unselected patients presenting with suspected acute myocardial infarction (AMI) and adjudication based on high-sensitivity cardiac troponin (hs-cTn).

METHODS AND RESULTS

In an ongoing prospective multicenter diagnostic study, consecutive patients presenting with suspected AMI to the emergency department and available GDF-15 and hs-cTnT concentrations were included. Adjudication of AMI was performed central by two independent cardiologists using all available clinical information including cardiac imaging and serial hs-cTn concentrations. Overall, 718 patients were included, with 23% (162/718) having an adjudicated diagnosis of AMI. The cumulative incidence of death within 2 years was 19% in patients with AMI (30 deaths in 162 patients) versus 5% in patients without AMI (25 deaths in 556 patients; P < 0.001). In AMI patients, GDF-15 provided an AUC of 0.89 (95% confidence interval [CI] 0.83-0.94) for 2-year death versus 0.55 (95% CI 0.44-0.66) for hs-cTnT (P < 0.001). A GDF-15 cutoff of ≤1560 ng/L predicted 2-year survival in 47% (76/162) of AMI patients and had 100% sensitivity (95% CI 88-100%) for 2-year death. In patients without AMI, GDF-15 provided an AUC of 0.83 (95% CI 0.76-0.89) versus 0.76 (95% CI 0.67-0.85) for hs-cTnT (P = 0.096). A GDF-15 cutoff of ≤886 ng/L predicted 2-year survival in 37% (203/556) of non-AMI patients and had 100% sensitivity (95% CI 86-100%) for 2-year death.

CONCLUSIONS

GDF-15 concentrations at emergency department presentation have a high predictive accuracy for all-cause death in patients with suspected AMI and allow the identification of a large proportion of AMI patients with very low mortality risk.

Diagnostic and prognostic value of biomarkers in acute myocardial infarction

The incidence of acute myocardial infarction (AMI) has been increasing rapidly in recent years, seriously endangering human health. Cardiac biomarkers play critical roles in the diagnosis and prognosis of AMI. Troponin is a highly sensitive and specific biomarker for AMI diagnosis and can independently predict adverse cardiac events. Other biomarkers such as N-terminal B-type natriuretic peptide and C reactive protein are also valuable predictors of cardiovascular prognosis. Recently, several novel biomarkers have been identified for the diagnosis and risk assessment in patients with AMI. A multibiomarker approach can potentially enhance the diagnostic accuracy and provide more information for the early risk stratification of AMI. In this review, we will summarise the biomarkers discovered in recent years and focus on their diagnostic and prognostic value for patients with AMI.

Potential associations of circulating growth differentiation factor-15 with sex hormones in male patients with coronary artery disease

This study aimed to explore the association between growth differentiation factor-15 (GDF-15), a stress-induced factor, and sex hormones in male patients with coronary artery disease (CAD). In this study, we recruited 253 male patients with CAD and 205 male controls. Patients were divided into three groups in accordance with GDF-15 tertiles. Serum levels of GDF-15, testosterone, estradiol and other biochemical variables were measured. Serum levels of GDF-15 were significantly increased and serum testosterone and testosterone/estradiol ratio (T/E2 ratio) were significantly decreased in CAD patients compared with controls. Patients with high GDF-15 levels had lower testosterone (203.97, 95% CI 154.67-328.30 vs. 303.98, 95% CI 246.93-345.66; P = 0.001) and T/E2 ratio (8.82, 95% CI 5.77-11.41 vs. 11.07, 95% CI 7.91-14.32; P = 0.013). Correlation analyses showed that serum GDF-15 levels inversely correlated with testosterone levels (r = -0.339) and T/E2 ratio (r = -0.365) (both P < 0.001). In multivariate regression analyses, the association between GDF-15 and T/E2 ratio was maintained (B=-0.442, 95% CI -99.568 to -6.991, P = 0.015). Furthermore, in vitro studies showed a synergistic effect of testosterone and estradiol on GDF-15 secretion, and demonstrated that testosterone association with estradiol decreased GDF-15 secretion through androgen receptor/estrogen receptor-mediated pathways. Together, these results suggest that upregulation of GDF-15 in the presence of low and imbalanced sex hormone levels may contribute to CAD. Thus, restoring the balance of testosterone and estradiol may inhibit the effects of GDF-15 and serve as a promising therapeutic strategy for the treatment of CAD.

Additional Diagnostic Value of Growth Differentiation Factor-15 (GDF-15) to N-Terminal B-Type Natriuretic Peptide (NT-proBNP) in Patients with Different Stages of Heart Failure

BACKGROUND Growth differentiation factor-15 (GDF-15) is a promising biomarker of cardiac remodeling. The purpose of this study was to explore the diagnostic value of plasma GDF-15 levels in different stages of heart failure (HF) and to assess the relationship with ventricular remodeling. MATERIAL AND METHODS We enrolled 219 HF patients from the Department of Cardiology in Tianjin Union Medical Center as the HF group and 32 healthy subjects as the control group. Circulating GDF-15, NT-proBNP, procollagen I C-terminal propeptide (PICP), and N-terminal procollagen III propeptide (PIIINP) levels were measured using ELISA. Associations between GDF-15 and clinical indicators in cardiac remodeling were assessed using receiver operating characteristic (ROC) curves and Spearman correlation. All the patients were followed up for 1 year. RESULTS The level of plasma GDF-15 in HF patients was higher than in the control group (P<0.05) and increased with higher ACCF/AHA and NYHA classification (P<0.05). Patients with HFrEF had higher GDF-15 levels compared to patients with HFmrEF (P<0.05). GDF-15 and left ventricular mass index (LVMI) were significantly increased as early as the pre-clinical HF stage. Also, GDF-15 levels were positively correlated to LVMI (r=0.433, P<0.05), PICP (r=0.378, P<0.001) and PIIINP (r=0.382, P<0.001). ROC curves were constructed and GDF-15 plus NT-proBNP (AUC=0.905, 95%CI: 0.868-0.942, P<0.001) was superior to NT-proBNP (AUC=0.869, 95%CI: 0.825-0.913, P<0.001) in identifying HF. GDF-15 levels did not predict prognosis after a 1-year follow-up period. CONCLUSIONS GDF-15 combined with NT-proBNP significantly improves the accuracy of diagnosing HF. Plasma GDF-15 levels can indirectly reflect the degree of cardiac remodeling and fibrosis.

GDF-15 predicts cardiovascular events in acute chest pain patients

Background

Treatment of patients presenting with possible acute myocardial infarction (AMI) is based on timely diagnosis and proper risk stratification aided by biomarkers. We aimed at evaluating the predictive value of GDF-15 in patients presenting with symptoms suggestive of AMI.

Methods

Consecutive patients presenting with suspected AMI were enrolled in three study centers. Cardiovascular events were assessed during a follow-up period of 6 months with a combined endpoint of death or MI.

Results

From the 1818 enrolled patients (m/f = 1208/610), 413 (22.7%) had an acute MI and 63 patients reached the combined endpoint. Patients with MI and patients with adverse outcome had higher GDF-15 levels compared with non-MI patients (967.1pg/mL vs. 692.2 pg/L, p<0.001) and with event-free patients (1660 pg/mL vs. 756.6 pg/L, p<0.001). GDF-15 levels were lower in patients with SYNTAX score ≤ 22 (797.3 pg/mL vs. 947.2 pg/L, p = 0.036). Increased GDF-15 levels on admission were associated with a hazard ratio of 2.1 for death or MI (95%CI: 1.67–2.65, p<0.001) in a model adjusted for age and sex and of 1.57 (1.13–2.19, p = 0.008) adjusted for the GRACE score variables. GDF-15 showed a relevant reclassification with regards to the GRACE score with an overall net reclassification index (NRI) of 12.5% and an integrated discrimination improvement (IDI) of 14.56% (p = 0.006).

Conclusion

GDF-15 is an independent predictor of future cardiovascular events in patients presenting with suspected MI. GDF-15 levels correlate with the severity of CAD and can identify and risk-stratify patients who need coronary revascularization.

Growth Differentiation Factor 15 as a Biomarker in Cardiovascular Disease

BACKGROUND

Growth differentiation factor 15 (GDF-15) is expressed and secreted in response to inflammation, oxidative stress, hypoxia, telomere erosion, and oncogene activation. Cardiovascular (CV) disease is a major driver of GDF-15 production. GDF-15 has favorable preanalytic characteristics and can be measured in serum and plasma by immunoassay.

CONTENT

In community-dwelling individuals higher concentrations of GDF-15 are associated with increased risks of developing CV disease, chronic kidney disease, and cancer, independent of traditional CV risk factors, renal function, and other biomarkers (C-reactive protein, B-type natriuretic peptide, cardiac troponin). Low concentrations of GDF-15 are closely associated with longevity. GDF-15 is as an independent marker of all-cause mortality and CV events in patients with coronary artery disease, and may help select patients with non-ST-elevation acute coronary syndrome for early revascularization and more intensive medical therapies. GDF-15 is independently associated with mortality and nonfatal events in atrial fibrillation and heart failure (HF) with preserved or reduced ejection fraction. GDF-15 reflects chronic disease burden and acute perturbations in HF and responds to improvements in hemodynamic status. GDF-15 is independently associated with major bleeding in patients receiving antithrombotic therapies and has been included in a new bleeding risk score, which may become useful for decision support.

SUMMARY

GDF-15 captures distinct aspects of CV disease development, progression, and prognosis, which are not represented by clinical risk predictors and other biomarkers. The usefulness of GDF-15 to guide management decisions and discover new treatment targets should be further explored.

Gdf-15 deficiency does not alter vulnerability of nigrostriatal dopaminergic system in MPTP-intoxicated mice

Growth/differentiation factor-15 (Gdf-15) is a member of the transforming growth factor-β (Tgf-β) superfamily and has been shown to be a potent neurotrophic factor for midbrain dopaminergic (DAergic) neurons both in vitro and in vivo. Gdf-15 has also been shown to be involved in inflammatory processes. The aim of this study was to identify the role of endogenous Gdf-15 in the MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) mouse model of Parkinson's disease (PD) by comparing Gdf-15 (+/+) and Gdf-15 (-/-) mice. At 4 days and 14 days post-MPTP administration, both Gdf-15 (+/+) and Gdf-15 (-/-) mice showed a similar decline in DAergic neuron numbers and in striatal dopamine (DA) levels. This was followed by a comparable restorative phase at 90 days and 120 days, indicating that the absence of Gdf-15 does not affect the susceptibility or the recovery capacity of the nigrostriatal system after MPTP administration. The MPTP-induced microglial and astrocytic response was not significantly altered between the two genotypes. However, pro-inflammatory and anti-inflammatory cytokine profiling revealed the differential expression of markers in Gdf-15 (+/+) and Gdf-15 (-/-) mice after MPTP administration. Thus, the MPTP mouse model fails to uncover a major role of endogenous Gdf-15 in the protection of MPTP-lesioned nigrostriatal DAergic neurons, in contrast to its capacity to protect the 6-hydroxydopamine-intoxicated nigrostriatal system.

High-sensitivity troponin assays for the early rule-out or diagnosis of acute myocardial infarction in people with acute chest pain: a systematic review and cost-effectiveness analysis

BACKGROUND

Early diagnosis of acute myocardial infarction (AMI) can ensure quick and effective treatment but only 20% of adults with emergency admissions for chest pain have an AMI. High-sensitivity cardiac troponin (hs-cTn) assays may allow rapid rule-out of AMI and avoidance of unnecessary hospital admissions and anxiety.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of hs-cTn assays for the early (within 4 hours of presentation) rule-out of AMI in adults with acute chest pain.

METHODS

Sixteen databases, including MEDLINE and EMBASE, research registers and conference proceedings, were searched to October 2013. Study quality was assessed using QUADAS-2. The bivariate model was used to estimate summary sensitivity and specificity for meta-analyses involving four or more studies, otherwise random-effects logistic regression was used. The health-economic analysis considered the long-term costs and quality-adjusted life-years (QALYs) associated with different troponin (Tn) testing methods. The de novo model consisted of a decision tree and Markov model. A lifetime time horizon (60 years) was used.

RESULTS

Eighteen studies were included in the clinical effectiveness review. The optimum strategy, based on the Roche assay, used a limit of blank (LoB) threshold in a presentation sample to rule out AMI [negative likelihood ratio (LR-) 0.10, 95% confidence interval (CI) 0.05 to 0.18]. Patients testing positive could then have a further test at 2 hours; a result above the 99th centile on either sample and a delta (Δ) of ≥ 20% has some potential for ruling in an AMI [positive likelihood ratio (LR+) 8.42, 95% CI 6.11 to 11.60], whereas a result below the 99th centile on both samples and a Δ of < 20% can be used to rule out an AMI (LR- 0.04, 95% CI 0.02 to 0.10). The optimum strategy, based on the Abbott assay, used a limit of detection (LoD) threshold in a presentation sample to rule out AMI (LR- 0.01, 95% CI 0.00 to 0.08). Patients testing positive could then have a further test at 3 hours; a result above the 99th centile on this sample has some potential for ruling in an AMI (LR+ 10.16, 95% CI 8.38 to 12.31), whereas a result below the 99th centile can be used to rule out an AMI (LR- 0.02, 95% CI 0.01 to 0.05). In the base-case analysis, standard Tn testing was both most effective and most costly. Strategies considered cost-effective depending upon incremental cost-effectiveness ratio thresholds were Abbott 99th centile (thresholds of < £6597), Beckman 99th centile (thresholds between £6597 and £30,042), Abbott optimal strategy (LoD threshold at presentation, followed by 99th centile threshold at 3 hours) (thresholds between £30,042 and £103,194) and the standard Tn test (thresholds over £103,194). The Roche 99th centile and the Roche optimal strategy [LoB threshold at presentation followed by 99th centile threshold and/or Δ20% (compared with presentation test) at 1-3 hours] were extendedly dominated in this analysis.

CONCLUSIONS

There is some evidence to suggest that hs-CTn testing may provide an effective and cost-effective approach to early rule-out of AMI. Further research is needed to clarify optimal diagnostic thresholds and testing strategies.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005939.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Growth/differentiation factor-15 deficiency compromises dopaminergic neuron survival and microglial response in the 6-hydroxydopamine mouse model of Parkinson's disease

Growth/differentiation factor-15 (Gdf-15) is a member of the TGF-β superfamily and a pleiotropic, widely distributed cytokine, which has been shown to play roles in various pathologies, including inflammation. Analysis of Gdf-15(-/-) mice has revealed that it serves the postnatal maintenance of spinal cord motor neurons and sensory neurons. In a previous study, exogenous Gdf-15 rescued 6-hydroxydopamine (6-OHDA) lesioned Gdf-15(+/+) nigrostriatal dopaminergic (DAergic) neurons in vitro and in vivo. Whether endogenous Gdf-15 serves the physiological maintenance of nigrostriatal DAergic neurons in health and disease is not known and was addressed in the present study. Stereotactic injection of 6-OHDA into the medial forebrain bundle (MFB) led to a significant decline in the numbers of DAergic neurons in both Gdf-15(+/+) and Gdf-15(-/-) mice over a time-period of 14days. However, this decrease was exacerbated in the Gdf-15(-/-) mice, with only 5.5% surviving neurons as compared to 24% in the Gdf-15(+/+) mice. Furthermore, the microglial response to the 6-OHDA lesion was reduced in Gdf-15(-/-) mice, with significantly lower numbers of total and activated microglia and a differential cytokine expression as compared to the Gdf-15(+/+) mice. Using in vitro models, we could demonstrate the importance of endogenous Gdf-15 in promoting DAergic neuron survival thus highlighting its relevance in a direct neurotrophic supportive role. Taken together, these results indicate the importance of Gdf-15 in promoting survival of DAergic neurons and regulating the inflammatory response post 6-OHDA lesion.

Associations of Circulating Growth Differentiation Factor-15 and ST2 Concentrations With Subclinical Vascular Brain Injury and Incident Stroke

BACKGROUND AND PURPOSE

Growth differentiation factor-15 (GDF-15) and soluble (s)ST2 are markers of cardiac and vascular stress. We investigated the associations between circulating concentrations of these biomarkers and incident stroke and subclinical vascular brain injury in a sample from the Framingham Offspring cohort.

METHODS

We followed 3374 stroke- and dementia-free individuals (mean age, 59.0±9.7 years; 53% women) attending the Framingham Offspring sixth examination cycle 11.8±3.0 years for incident stroke. A subsample of 2463 individuals underwent brain magnetic resonance imaging and neuropsychological testing ≈4.0±1.7 years after the sixth examination.

RESULTS

After adjustment for traditional cardiovascular risk factors, B-type natriuretic peptide, high-sensitivity C-reactive protein, and urine albumin levels, higher stress biomarker levels were associated cross-sectionally with lower brain volumes (β coefficients for intracranial volume comparing fourth [Q4] versus first biomarker [Q1] quartiles: -0.71% for GDF-15; P=0.002 and 0.47% for sST2; P=0.02) and worse performance on the visual reproduction test (β coefficients for Q4 versus Q1: -0.62 for GDF-15; P=0.009 and -0.40 for sST2; P=0.04). Higher GDF-15 concentrations were also associated with greater log-transformed white-matter hyperintensity volumes (β for Q4 versus Q1=0.19; P=0.01). Prospectively, a total of 203 (6%) individuals developed incident stroke/transient ischemic attack during follow-up. After multivariable adjustment, sST2 remained significantly associated with stroke/transient ischemic attack, hazard ratio for Q4 versus Q1 of 1.76, 95% confidence interval of 1.06 to 2.92, and P=0.03.

CONCLUSIONS

Circulating GDF-15 and sST2 are associated with subclinical brain injury and cognitive impairment. Higher sST2 concentrations are also associated with incident stroke, suggesting potential links between cardiac stress biomarkers and brain injury.

No Added Value of Novel Biomarkers in the Diagnostic Assessment of Patients Suspected of Acute Coronary Syndrome

BACKGROUND

Despite the availability of high-sensitive troponin (hs-cTnT), there is still room for improvement in the diagnostic assessment of patients suspected of acute coronary syndrome (ACS). Apart from serial biomarker testing, which is time-consuming, novel biomarkers like copeptin have been proposed to expedite the early diagnosis of suspected ACS in addition to hs-cTnT. We determined whether placenta derived growth factor (PlGF), soluble Fms-like tyrosine kinase 1 (sFlt-1), myoglobin, N-terminal prohormone B-type Natriuretic Peptide (NT-proBNP), growth-differentiation factor 15 (GDF-15) and copeptin improved early assessment of chest pain patients.

METHODS

This prospective, single centre diagnostic FAME-ER study included patients presenting to the ED with symptoms suggestive of ACS. Blood was collected to measure biomarkers, notably, hs-cTnT was retrospectively assessed. Added value of markers was judged by increase in AUC using multivariable logistic regression.

RESULTS

Of 453 patients enrolled, 149 (33%) received a final diagnosis of ACS. Hs-cTnT had the highest diagnostic value in both univariable and multivariable analysis. PPVs of the biomarkers ranged from 23.5% (PlGF) to 77.9% (hs-cTnT), NPVs from 67.0% (PlGF) to 86.4% (hs-cTnT). Only myoglobin yielded diagnostic value in addition to clinical symptoms and electrocardiography (ECG) (AUC of clinical model 0.80) with AUC of 0.84 (p<0.001). However, addition of hs-cTnT was superior (AUC 0.89, p<0.001). Addition of the biomarkers to our clinical model and hs-cTnT did not or only marginally (GDF-15) improved diagnostic performance.

CONCLUSION

When assessing patients suspected of ACS, only myoglobin had added diagnostic value beyond clinical symptoms and ECG. However, when combined with hs-cTnT, it yields no additional diagnostic value. PlGF, sFlt-1, NT-proBNP, GDF-15 and copeptin had no added value to the clinical model or hs-cTnT.

Cardiac myosin-binding protein C: a potential early biomarker of myocardial injury

Cardiac troponins are released and cleared slowly after myocardial injury, complicating the diagnosis of early, and recurrent, acute myocardial infarction. Cardiac myosin-binding protein C (cMyC) is a similarly cardiac-restricted protein that may have different release/clearance kinetics. Using novel antibodies raised against the cardiac-specific N-terminus of cMyC, we used confocal microscopy, immunoblotting and immunoassay to document its location and release. In rodents, we demonstrate rapid release of cMyC using in vitro and in vivo models of acute myocardial infarction. In patients, with ST elevation myocardial infarction (STEMI, n = 20), undergoing therapeutic ablation of septal hypertrophy (TASH, n = 20) or having coronary artery bypass surgery (CABG, n = 20), serum was collected prospectively and frequently. cMyC appears in the serum as full-length and fragmented protein. Compared to cTnT measured using a contemporary high-sensitivity commercial assay, cMyC peaks earlier (STEMI, 9.3 ± 3.1 vs 11.8 ± 3.4 h, P < 0.007; TASH, 9.7 ± 1.4 vs 21.6 ± 1.4 h, P < 0.0001), accumulates more rapidly (during first 4 h after TASH, 25.8 ± 1.9 vs 4.0 ± 0.4 ng/L/min, P < 0.0001) and disappears more rapidly (post-CABG, decay half-time 5.5 ± 0.8 vs 22 ± 5 h, P < 0.0001). Our results demonstrate that following defined myocardial injury, the rise and fall in the serum of cMyC is more rapid than that of cTnT. We speculate that these characteristics could enable earlier diagnosis of myocardial infarction and reinfarction in suspected non-STEMI, a population not included in this early translational study.

Diagnostic and prognostic value of autoantibodies anti-apolipoprotein A-1 and anti-phosphorylcholine in acute non-ST elevation myocardial infarction

BACKGROUND

Autoantibodies have been shown to play a critical role in predicting major adverse cardiovascular events in atherosclerotic patients. We aimed to assess the diagnostic accuracy of autoantibodies to apolipoprotein A-1 (anti-apoA-1 IgG) and to phosphorylcholine (anti-PC IgM) for non-ST segment elevation acute myocardial infarction (NSTEMI) and to explore their potential prognostic value.

METHODS

This prospective multicentre study included 1072 patients presenting to the emergency department for suspected NSTEMI. The final diagnosis was adjudicated by two independent cardiologists. For both antibodies alone or expressed as a ratio (anti-apoA-1 IgG/anti-PC IgM), we determined their (i) diagnostic accuracy for NSTEMI and (ii) prognostic accuracy for major adverse cardiovascular events (MACE) during 1-year follow-up.

RESULTS

A total of 154 patients (14%) had a final diagnosis of NSTEMI. Diagnostic accuracy for the diagnosis of NSTEMI as quantified by the area under the receiver operating characteristics curve (AUC) was very low for both autoantibodies separately as well as combined as a ratio: AUC anti-apoA-1 IgG 0.50 (95%CI, 0.47-0.53, P = 0.99), AUC anti-PC IgM 0.53 (95%CI, 0.50-0.56, P = 0.30) and AUC of the ratio 0.52 (95%CI, 0.49-0.55, P = 0.47). Adding the anti-apoA-1 IgG/Anti-PC IgM ratio to hs-cTnT did not provide incremental diagnostic value over hs-cTnT alone. MACE occurred in 221 patients (21%) during follow-up. The autoantibodies, separately or expressed as ratio, also had very low accuracy to predict MACE (p=ns).

CONCLUSIONS

Anti-apoA-1 IgG and anti-PC IgM autoantibodies did not have diagnostic or prognostic value in patients with NSTEMI.

GDF-15 as a Target and Biomarker for Diabetes and Cardiovascular Diseases: A Translational Prospective

Growth differentiation factor-15 (GDF-15) is a stress responsive cytokine. It is highly expressed in cardiomyocytes, adipocytes, macrophages, endothelial cells, and vascular smooth muscle cells in normal and pathological condition. GDF-15 increases during tissue injury and inflammatory states and is associated with cardiometabolic risk. Increased GDF-15 levels are associated with cardiovascular diseases such as hypertrophy, heart failure, atherosclerosis, endothelial dysfunction, obesity, insulin resistance, diabetes, and chronic kidney diseases in diabetes. Increased GDF-15 level is linked with the progression and prognosis of the disease condition. Age, smoking, and environmental factors are other risk factors that may increase GDF-15 level. Most of the scientific studies reported that GDF-15 plays a protective role in different tissues. However, few reports show that the deficiency of GDF-15 is beneficial against vascular injury and inflammation. GDF-15 protects heart, adipose tissue, and endothelial cells by inhibiting JNK (c-Jun N-terminal kinase), Bad (Bcl-2-associated death promoter), and EGFR (epidermal growth factor receptor) and activating Smad, eNOS, PI3K, and AKT signaling pathways. The present review describes the different animal and clinical studies and patent updates of GDF-15 in diabetes and cardiovascular diseases. It is a challenge for the scientific community to use GDF-15 information for patient monitoring, clinical decision-making, and replacement of current treatment strategies for diabetic and cardiovascular diseases.

Clinical usefulness of novel serum and imaging biomarkers in risk stratification of patients with stable angina

Inflammatory mediators appear to be the most intriguing yet confusing subject, regarding the management of patients with acute coronary syndromes (ACS). The current inflammatory concept of atherosclerotic coronary artery disease (CAD) led many investigators to concentrate on systemic markers of inflammation, as well as imaging techniques, which may be helpful in risk stratification and prognosis assessment for cardiovascular events. In this review, we try to depict many of the recently studied markers regarding stable angina (SA), their clinical usefulness, and possible future applications in the field.

Acute coronary syndrome - the present and future role of biomarkers

Over the past two decades there have been dramatic changes in the diagnosis, treatment and prognosis of acute coronary syndrome (ACS). Several new treatment modalities have been added and the prognosis has improved dramatically. Biomarkers play a crucial role in the management of ACS. At present, cardiac troponin is the biomarker of choice for diagnosis of acute myocardial infarction (AMI). Currently, there are no other biomarkers, which can compete, neither regarding specificity nor regarding early sensitivity. However, there is still a clinical need of a biomarker able to reliably rule-in or rule-out AMI immediately on admission. MicroRNAs seem to be promising new candidates for diagnostic purposes. The optimal combination of biomarkers and new imaging techniques is another important area for research. The list of biomarkers associated with an adverse prognosis in ACS is long. However, for most of them it has been very difficult to prove an added clinical value. Only cardiac troponin, and to some degree also B-type natriuretic peptides, is widely used in clinical practice for risk assessment. Among new markers, growth differentiation factor 15 and the mid-regional part of the prohormone of adrenomedullin, have shown some promising results. Since the renal function is assessed in clinical routine, also markers of the renal function have gained increasing interest. Cardiac troponin has been proven useful for selection of antithrombotic, antiplatelet and invasive treatment. Besides cardiac troponin, no other markers have consistently been shown to be useful for selection of specific treatments.

Growth differentiation factor 15 and cardiovascular events in patients with stable ischemic heart disease (The Heart and Soul Study)

BACKGROUND

Growth differentiation factor 15 (GDF-15) is a relatively new biomarker that predicts mortality in patients with chronic stable angina or acute coronary syndrome. However, the association of GDF-15 with cardiovascular (CV) events and the mechanisms of this association are not well understood.

METHODS

We measured plasma GDF-15 and cardiac disease severity in 984 patients with stable ischemic heart disease who were recruited for the Heart and Soul Study between September 2000 and December 2002. Subsequent CV events (myocardial infarction, stroke, and CV death), hospitalization for heart failure, and all-cause mortality were determined by chart review during an average of 8.9-year follow-up.

RESULTS

Each doubling in GDF-15 was associated with a 2.5-fold increased rate of CV events (hazard ratio [HR] 2.53, 95% CI 2.13-3.01, P < .001). This association persisted after extensive adjustment for covariates including comorbid conditions, measures of cardiac disease severity, cardiac function, inflammatory markers, and adipokines (HR 1.44, 95% CI 1.11-1.87, P < .01). Participants who had GDF-15 levels in the highest tertile had higher mortality compared with those in the lowest tertile (HR 2.73, 95% CI 1.80-4.15, P ≤ .001 adjusted for all covariates). Addition of GDF-15 to existing risk factors resulted in a 50% change in net reclassification of patients' risk for mortality.

CONCLUSIONS

Higher levels of GDF-15 are associated with major CV events in patients with stable ischemic heart disease. This suggests that GDF-15 is capturing an element of risk not explained by other known risk factors.

Emerging families of biomarkers for coronary artery disease: inflammatory mediators

Introduction

Inflammation has been implicated in the development of atherosclerosis in patients with acute coronary syndrome. C-reactive protein is an established nonspecific prognostic inflammatory biomarker for patients with acute coronary syndrome in the medical literature. This has led to a concerted effort to identify circulating inflammatory biomarkers to facilitate predicting the risk for and diagnosing coronary artery disease in at-risk subjects. The objective of this study was to search after novel inflammatory biomarkers reported as useful for diagnosing coronary artery disease.

Methods

The PubMed database was searched for reports published from January 1, 2000 to June 30, 2012 of novel circulating biomarkers for coronary artery disease in addition to the established biomarker, C-reactive protein. The search terms used were “infarction”, “biomarkers”, and “markers”, and only original articles describing clinical trials that were written in English were included. All published articles were separately examined carefully after novel inflammatory markers for acute coronary syndrome. All irrelevant publications without content pertaining to inflammatory biomarkers for acute coronary syndrome were excluded from this study. Our results reflect all articles concerning biomarkers in humans.

Results

The PubMed search yielded 4,415 research articles. After further analysis, all relevant published original articles examining 53 biomarkers were included in this review, which identified 46 inflammation biomarkers useful for detecting coronary artery disease.

Conclusion

The emergence of diverse novel biomarkers for coronary artery disease has provided insight into the varied pathophysiology of this disease. Inflammatory biomarkers have tremendous potential in aiding the prediction of acute coronary syndrome and recurrent ischemic episodes, and will eventually help improve patient care and management.