Increased serum neopterin: a marker of coronary artery disease activity in women

Construction of a Zn(II)-Eu(III) Nanoring with Temperature-Dependent Luminescence for the Qualitative and Quantitative Detection of Neopterin as an Inflammatory Marker

A nine-metal Zn(II)-Eu(III) nanoring 1 with a diameter of about 2.3 nm was constructed by the use of a long-chain Schiff base ligand. It shows a luminescence response to neopterin (Neo) through the enhancement of lanthanide emission with high selectivity and sensitivity, which can be used to quantitatively analyze the concentrations of Neo in fetal calf serum and urine. The luminescence sensing of 1 to Neo is temperature-dependent, and it displays more obvious response behavior at lower temperatures. Filter paper strips bearing 1 can be used to qualitatively detect Neo by the color change from chartreuse to red under a UV lamp. The limit of detection is as low as 3.77 × 10-2 nM.

Plasma levels of soluble VEGF receptor isoforms, circulating pterins and VEGF system SNPs as prognostic biomarkers in patients with acute coronary syndromes

Background

Development of collateral circulation in coronary artery disease is cardio-protective. A key process in forming new blood vessels is attraction to occluded arteries of monocytes with their subsequent activation as macrophages. In patients from a prospectively recruited post-acute coronary syndromes cohort we investigated the prognostic performance of three products of activated macrophages, soluble vascular endothelial growth factor (VEGF) receptors (sFlt-1 and sKDR) and pterins, alongside genetic variants in VEGF receptor genes, VEGFR-1 and VEGFR-2.

Methods

Baseline levels of sFlt-1 (VEGFR1), sKDR (VEGFR2) and pterins were measured in plasma samples from subgroups (n = 513; 211; 144, respectively) of the Coronary Disease Cohort Study (CDCS, n = 2067). DNA samples from the cohort were genotyped for polymorphisms from the VEGFR-1 gene SNPs (rs748252 n = 2027, rs9513070 n = 2048) and VEGFR-2 gene SNPs (rs2071559 n = 2050, rs2305948 n = 2066, rs1870377 n = 2042).

Results

At baseline, levels of sFlt-1 were significantly correlated with age, alcohol consumption, NTproBNP, BNP and other covariates relevant to cardiovascular pathophysiology. Total neopterin levels were associated with alcohol consumption at baseline. 7,8 dihydroneopterin was associated with BMI. The A allele of VEGFR-2 variant rs1870377 was associated with higher plasma sFlt-1 and lower levels of sKDR at baseline. Baseline plasma sFlt-1 was univariately associated with all cause mortality with (p < 0.001) and in a Cox’s proportional hazards regression model sFlt-1 and pterins were both associated with mortality independent of established predictors (p < 0.027).

Conclusions

sFlt-1 and pterins may have potential as prognostic biomarkers in acute coronary syndromes patients. Genetic markers from VEGF system genes warrant further investigation as markers of levels of VEGF system components in these patients.

Trial registration

Australian New Zealand Clinical Trials Registry. ACTRN12605000431628. 16 September 2005, Retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0894-1) contains supplementary material, which is available to authorized users.

Important Biomarkers that Play a Role in the Chronic Obstructive Pulmonary Disease Process

BACKGROUND

Chronic obstructive pulmonary disease (COPD) that includes multiple mechanisms such as inflammation, infection, smoking, hypoxia, and lack of antioxidant response can cause oxidative stress. In our study, we aimed to determine the changes in some oxidative stress [malondialdehyde and glutathione] and some cellular immunity markers (neopterin and TGF-b) in patients diagnosed with COPD and determine the damage to the organism.

METHODS

While the high-performance liquid chromatography (HPLC) method (Immuchrom kit, Germany) was utilized to determine MDA, GSH and NP levels, the ELISA method was used for TGF-b levels.

RESULTS

All obtained data regarding each parameter were compared with both COPD and healthy individuals and between parameters. There was a statistically significant difference between the control group of healthy subjects and COPD group in all parameters (p<0.05). A negative and correlation between oxidant MDA and antioxidant GSH parameters was determined (p=-0.394).

CONCLUSIONS

As a result, it was seen that oxidative balance changed in the patient group and cellular immunity increased. When the obtained data and literature are taken into account, these changes occurring in oxidative balance and cellular immunity are of importance in determining the development in the pathogenesis of COPD, treatment op - tions and their risks for heart disease in advance.

Associations of plasma hepcidin with mortality risk in patients with coronary artery disease

Background

Increased blood hepcidin may be associated with the presence and promotion of atherosclerosis, the association of hepcidin with mortality among coronary artery disease (CAD) patients remains unknown. We sought to assess the relationship of hepcidin and all-cause and cardiovascular disease (CVD) mortality among CAD patients with and without acute coronary syndrome (ACS).

Methods and Results

This study included 759 patients with ACS and 526 patients with stable CAD. After an average follow-up of 4.1 years, 154 deaths were recorded, 114 were due to CVD. After adjusting for CVD risk factors and inflammatory markers, the plasma hepcidin was positively associated with all-cause and CVD mortality in the ACS patients, the multivariable-adjusted hazard ratios (HRs) across tertiles of hepcidin were 1.00, 2.18 (95% CI 1.23-3.94), and 2.82 (95% CI 1.59-5.12) for all-cause mortality (P_trend=0.006), and 1.00, 2.20 (95% CI 1.12-4.05), and 2.64 (95% CI 1.41-5.65) for CVD mortality (P_trend=0.01). The C-index and net reclassification improvement when including hepcidin in traditional CVD models were 1.6% and 21.5% for all-cause mortality, 1.4% and 23.5% for CVD mortality, respectively, (P<0.001).

Conclusions

Plasma hepcidin was positively associated with mortality in ACS patients. Hepcidin may be a potential biomarker for risk prediction in ACS patients.

Highly efficient SERS-based detection of cerebrospinal fluid neopterin as a diagnostic marker of bacterial infection

A highly efficient recognition unit based on surface-enhanced Raman spectroscopy (SERS) was developed as a promising, fast, and sensitive tool for detection of meningococcal meningitis, which is an extremely serious and often fatal disease of the nervous system (an inflammation of the lining around the brain and spinal cord). The results of this study confirmed that there were specific differences in SERS spectra between cerebrospinal fluid (CSF) samples infected by Neisseria meningitidis and the normal CSF, suggesting a potential role for neopterin in meningococcal meningitis detection and screening applications. To estimate the best performance of neopterin as a marker of bacterial infection, principal component analysis (PCA) was performed in a selected region (640–720 cm⁻¹) where the most prominent SERS peak at 695 cm⁻¹ arising from neopterin was observed. The calculated specificity of 95 % and sensitivity of 98 % clearly indicate the effective diagnostic efficiency for differentiation between infected and control samples. Additionally, the limit of detection (LOD) of neopterin in CSF clinical samples was estimated. The level of neopterin was significantly higher in CSF samples infected by N. meningitidis (48 nmol/L), compared to the normal (control) group (4.3 nmol/L). Additionally, this work presents a new type of SERS-active nanostructure, based on polymer mats, that allows simultaneous filtration, immobilization, and enhancement of the Raman signal, enabling detection of spectra from single bacterial cells of N. meningitidis present in CSF samples. This provides a new possibility for fast and easy detection of bacteria in CSF and other clinical body fluids on a time scale of seconds. This method of detection produces consistent results faster and cheaper than traditional laboratory techniques, demonstrates the powerful potential of SERS for detection of disease, and shows the viability of future development in healthcare applications.

Cellular immune activity biomarker neopterin is associated hyperlipidemia: results from a large population-based study

BACKGROUND

Increased serum neopterin had been described in older age two decades ago. Neopterin is a biomarker of systemic adaptive immune activation that could be potentially implicated in metabolic syndrome (MetS). Measurements of waist circumference, triglycerides, high-density lipoprotein cholesterol (HDLC), systolic and diastolic blood pressure, glycated hemoglobin as components of MetS definition, and plasma total neopterin concentrations were performed in 594 participants recruited in the European Prospective Investigation into Cancer and Nutrition (EPIC).

RESULTS

Higher total neopterin concentrations were associated with reduced HDLC (9.7 %, p < 0.01 for men and 9.2 %, p < 0.01 for women), whereas no association was observed with the rest of the MetS components as well as with MetS overall (per 10 nmol/L: OR = 1.42, 95 % CI = 0.85-2.39 for men and OR = 1.38, 95 % CI = 0.79-2.43).

CONCLUSIONS

These data suggest that high total neopterin concentrations are cross-sectionally associated with reduced HDLC, but not with overall MetS.

ZnO oxide films for ultrasensitive, rapid, and label-free detection of neopterin by surface-enhanced Raman spectroscopy

Efficient and low-cost surface-enhanced Raman scattering (SERS) substrates based on Au coated zinc oxide layers for the detection of neopterin were prepared.

Estimation of serum neopterin in patients with acute coronary syndrome

BACKGROUND

The aim of our study was to determine neopterin levels in patients with acute coronary syndrome, in which the release of various cytokines activates the cellular immune system. There is an increase in the number and activity of T-cells in unstable atherosclerotic plaques, and of type 1 helper T-cells that produce interferon γ, which in turn produces neopterin, a byproduct of the guanosine triphosphate-biopterin pathway and a marker for activated macrophages.

METHODS

We studied 600 subjects consisting of healthy volunteers and patients with noncardiac chest pain, ST-segment elevation myocardial infarction, non-ST-segment elevation myocardial infarction, or unstable angina. Neopterin levels were determined by high-performance liquid chromatography.

RESULTS

Mean serum neopterin levels in ST-segment elevation myocardial infarction (11.5 ± 3.2 nmol·L(-1)), non-ST-segment elevation myocardial infarction (9.8 ± 2.9 nmol·L(-1)), and unstable angina patients (9.4 ± 2.3 nmol·L(-1)) were significantly higher than those in noncardiac chest pain patients (7.4 ± 1.9 nmol·L(-1)) and healthy volunteers (7.2 ± 0.6 nmol·L(-1); p < 0.001).

CONCLUSION

These findings suggest that serum neopterin levels may be a useful marker of systemic inflammation, and measurement of serum neopterin may be helpful in assessing the risk of developing coronary heart disease.

Potential Markers in Cardiac Hypertrophy?

Cardiomyopathies are diagnosed based on medical history of patient (symptoms and family history), physical examination, results of echocardiogram and in some situations additionally ECG or chest-X-ray results. Currently used non-invasive diagnostic methods, could be complemented by biochemical tests. In this review some emerging potential biomarkers such as: osteopontin, ST-2 receptor, osteoprotegerin, neopterin, urocortins, growth differentiation factor 15 and urotensin II are described. In current article human and non human investigations have been reviewed, since rat is most commonly used model in experimental cardiology and gives important foundations to clinical knowledge.

Neopterin and atherosclerotic plaque instability in coronary and carotid arteries

Inflammation plays a key role in atherosclerosis and plaque vulnerability, and monocyte/macrophage activation contributes to these processes. Neopterin, a by-product of the guanosine triphosphate pathway, is produced by activated macrophages on stimulation with interferon-γ released from T lymphocytes, and is an activation marker for monocytes/macrophages. Coronary angiographic studies have shown a relationship between increased circulating levels of neopterin and the presence of complex coronary lesions in patients with unstable angina pectoris (UAP). Furthermore, in an immunohistochemical study performed using coronary atherectomy specimens, a significantly higher prevalence of neopterin-positive macrophages was found in culprit lesions in patients with UAP than in those with stable angina pectoris (SAP). We recently clarified that the presence of complex carotid plaques detected by carotid ultrasound was related to increased circulating levels of neopterin, and immunohistochemical localization of neopterin was observed in complex carotid lesions obtained from carotid endarterectomy in patients with SAP. These findings suggest that neopterin is an important biomarker of plaque instability in both coronary and carotid atherosclerotic lesions.

Relations between concentrations of asymmetric dimethylarginine and neopterin as potential risk factors for cardiovascular diseases in haemodialysis-treated patients

OBJECTIVES

To investigate the correlation between concentrations of asymmetric dimethylarginine (ADMA) and neopterin (NP) as potential risk factors for cardiovascular diseases in chronic renal failure patients.

METHOD

In this study, 33 patients with renal failure before and after haemodialysis were compared with healthy control subjects. Serum ADMA and NP levels were measured using high performance liquid chromatography (HPLC).

RESULTS

When ADMA and NP concentrations in renal failure patients were compared before and after dialysis, before dialysis ADMA and NP concentrations were higher than those in the control group. However, ADMA and NP levels showed a falling mean and clear after dialysis. While there is no correlation between ADMA and NP levels before dialysis, there is a mean and positive correlation between ADMA and NP levels after dialysis.

CONCLUSION

Potential risk factors for cardiovascular diseases include high concentrations of both ADMA and NP levels in chronic renal failure patients. A correlation mean between ADMA and NP levels after dialysis was found, but no correlation between ADMA and NP levels before haemodialysis was discovered. These can be evaluated as two different risk factors independent from each other.

Sorting through new biomarkers

Early diagnosis of acute coronary syndromes (ACS) allows for efficient risk stratification, appropriate targeted therapies, and faster patient disposition within crowded emergency departments. Although only troponin testing is recommended for routine use in the 2007 American College of Cardiology/American Heart Association guidelines for non-ST-elevation ACS, emerging data support selected use of other biomarkers, including B-type natriuretic peptides (BNPs) and C-reactive protein. There remains a need to identify additional biomarkers in ACS to enhance risk stratification and to help guide therapeutic decisions in this increasingly complex area of cardiovascular medicine. Cardiac biomarkers may help to diagnosis ACS before cardiomyocyte necrosis, to influence the decision for early invasive treatment, and to provide a means of monitoring response to therapy. In this review, we assess new data in ACS with respect to troponins, BNPs, myeloperoxidase, fatty acid-binding protein, and monocyte chemoattractant protein-1. We also discuss novel biomarkers including growth deficient factor-15 and neopterin.

Association between serum neopterin, obesity and daytime sleepiness in patients with obstructive sleep apnea

OBJECTIVE

Obesity and obstructive sleep apnea (OSA) and systemic inflammation may interact through biochemical pathways. Neopterin (NP) is a monocyte/macrophage activation marker produced by macrophages in response to interferon-gamma secreted by activated T-lymphocytes. This study examines the association between NP, obesity and OSA.

PATIENTS AND METHODS

The study included 22 newly diagnosed OSA (+) patients and 18 OSA (-) patients. Subjects with history of coronary artery disease, transplant patients, history of alcohol and drug abuse, history of HIV and any other significant medical illnesses such as active infections, autoimmune disease, malignancy, liver disease, pulmonary disease (COPD, asthma,...), neuromuscular disease, patients on immunomodulating therapy or HMG-CoA reductase inhibitors were excluded.

RESULTS

There were no significant differences in age, body mass index (BMI), and smoking habits of the OSA (+) patients and OSA (-) patients. Serum NP levels did not show any significant difference between the OSA (+) patients and OSA (-) patients, however, NP levels were positively correlated with BMI (r=0.320, p=0.044). There was no significant correlation between NP and any of the polysomnographic parameters. The result of stepwise regression analyses (r(2)=0.320, p<0.001) showed that high serum NP levels (p=0.004) and apnea-hypopnea index (AHI) were a risk factor for elevated Epworth sleepiness score, independent of BMI.

CONCLUSION

We suggest that serum NP levels correlate with BMI. There was a significant relationship between serum NP levels and excessive daytime sleepiness in OSA patients.

Elevated serum neopterin levels and adverse cardiac events at 6 months follow-up in Mediterranean patients with non-ST-segment elevation acute coronary syndrome

BACKGROUND

Little information exists regarding the prognostic role of biomarkers of inflammation in Mediterranean patients. High C-reactive protein and neopterin levels - a marker of macrophage activation - predict cardiovascular events in stable angina patients and patients with acute coronary syndromes (ACS). We sought to assess whether plasma neopterin levels predict adverse clinical outcomes in Mediterranean patients with non-ST elevation (NSTE) ACS, i.e. unstable angina (UA) and NSTE myocardial infarction (MI).

METHODS

We prospectively assessed 397 patients (74% men) admitted with NSTEACS, 147 (37%) had unstable angina and 250 (63%) NSTEMI. Blood samples for neopterin and CRP assessment were obtained at admission. The study endpoint was the composite of cardiac death, acute myocardial infarction and unstable angina at 180 days.

RESULTS

Baseline neopterin concentrations (nmol/L) were similar in unstable angina and NSTEMI patients (8.3 [6.6-10.7] vs. 7.9 [6.2-10.9]; p=0.4). Fifty-nine patients (14.9%) had events during follow-up. Twenty-nine (21.5%) patients with neopterin levels in the highest third experienced the combined endpoint, compared to 30 (11.5%) patients with neopterin levels in the second and the lowest thirds (log-rank 7.435, p=0.024). On multivariable hazard Cox regression, neopterin (highest vs. 1st and 2nd thirds, HR 1.762, 95% CI [1.023-3.036]) was independently associated with the combined endpoint.

CONCLUSION

Increased neopterin levels are an independent predictor of 180-day adverse cardiac events in Mediterranean patients with NSTEACS.

Non-traditional biomarkers of atherosclerosis in stable and unstable coronary artery disease, do they differ?

BACKGROUND

Biomarkers of atherosclerosis are emerging as a potential tool for assessment of coronary artery disease (CAD) patients. As acute coronary syndrome (ACS), and stable CAD are distinguished in their pathophysiology it is conceivable that they are also characterized by different biomarkers of atherosclerosis.

METHODS

We systematically reviewed the literature for clinical studies of several non-traditional biomarkers of atherosclerosis reflecting various pathophysiological processes, namely macrophage-activity, oxidative-stress, tissue remodeling, and thrombosis in ACS and stable CAD to determine whether circulating biomarkers are differently expressed/predict outcome in these two clinical conditions.

RESULTS

Macrophage-activity (monocyte chemoattractant protein-1, neopterin), tissue-remodeling (matrix metalloproteinase-9) and thrombosis (tissue-factor) related biomarkers were consistently elevated in ACS compared to stable CAD, in accordance with the pathophysiological role of these mediators in plaque rupture, characterizing ACS. Thus, these biomarkers may be applicable for diagnosis of ACS. Additionally, neopterin was consistently shown to predict outcome in both stable and ACS patients and myeloperoxidase was strongly shown to predict outcome in ACS, implying for their potential role in risk stratification of these patients.

CONCLUSIONS

As ACS and stable CAD are characterized by different pathophysiological processes, it appears that the biomarkers that are associated with them are differently expressed in these two clinical conditions

Inflammatory and Apoptotic Markers in Ischemic Heart Disease Patients

Ischemic heart disease is the most frequent cause of cardiovascular morbidity and mortality. It is developed on the basis of atherosclerosis which is today considered a chronic inflammatory disease. It is documented by an increase in inflammatory and immune biomarkers, such as C-reactive protein, fibrinogen, neopterin, leukocytes, lymphocytes and others, that are significantly changed in patients with unstable angina or acute myocardial infarction. CRP is mostly studied. Increased concentrations of CRP are associated with a series of risk factors. CRP may predict recurrent events and mortality independently of cardiac troponin levels, and it is also an independent predictor of a cardiovascular event after adjustment for traditional risk factors. Although CRP currently appears to be the most promising biological marker, there is still controversy regarding its use in clinical practice. Both necrotic and apoptotic cell death are documented during atherogenesis, however, limited data are available about apoptotic markers in ischemic heart disease patients. Increasing evidence supports the existence of apoptotic death initiated by ligation of membrane-bound death receptors or by release of cytochrome c from mitochondria, as well as their regulators in the heart. The studies of serum markers show that the apoptotic process is disregulated in ischemic heart disease patients. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is present in stable atherosclerotic lesions, is increased in vulnerable plaques, but its serum levels are reduced significantly in patients with unstable angina. Serum Fas concentrations are increased and FasL are decreased in subjects at high cardiovascular risk. The results of our study show significant changes in serum Fas, FasL, and Bcl-2 concentrations, and lymphocyte caspase-3 activity in different stages of ischemic heart disease. For now, there is evidence that statins are effective in the regulation of some apoptotic markers. The better understanding of the pathways of apoptosis and their regulation is promissing in yielding novel therapeutic targets for cardiovascular disease.

Potential to inhibit growth of atherosclerotic plaque development through modulation of macrophage neopterin/7,8-dihydroneopterin synthesis

The rise in plasma neopterin observed with increasing severity of vascular disease is a strong indicator of the inflammatory nature of atherosclerosis. Plasma neopterin originates as the oxidation product of 7,8-dihydroneopterin secreted by gamma-interferon stimulated macrophages within atherosclerotic plaques. Neopterin is increasingly being used as a marker of inflammation during clinical management of patients with a range of disorders including atherosclerosis. Yet the role of 7,8-dihydroneopterin/neopterin synthesis during the inflammatory process and plaque formation remains poorly understood and controversial. This is partially due to the unresolved role oxidants play in atherosclerosis and the opposing roles of 7,8-dihydroneopterin/neopterin. Neopterin can act as pro-oxidant, enhancing oxidant damage and triggering apoptosis in a number of different cell types. Neopterin appears to have some cellular signalling properties as well as being able to chelate and enhance the reactivity of transition metal ions during Fenton reactions. In contrast, 7,8-dihydroneopterin is also a radical scavenger, reacting with and neutralizing a range of reactive oxygen species including hypochlorite, nitric oxide and peroxyl radicals, thus protecting lipoproteins and various cell types including macrophages. This has led to the suggestion that 7,8-dihydroneopterin is synthesized to protect macrophages from the oxidants released during inflammation. The oxidant/antioxidant activity observed in vitro appears to be determined both by the relative concentration of these compounds and the specific chemistry of the in vitro system under study. How these activities might influence or modulate the development of atherosclerotic plaque in vivo will be explored in this review.

Elevated levels of neopterin in sleep-disordered breathing

BACKGROUND

Sleep-disordered breathing (SDB) is increasingly being recognized as an independent risk factor for hypertension and cardiovascular disease. Recent evidence suggests that the maladaptive physiologic response to SDB, particularly cardiovascular effects, may result in part from systemic inflammation. Although abnormal cytokine levels have been documented in SDB, data on whether SDB is associated with cellular activation are limited. Thus, this investigation sought to determine whether neopterin, a marker released by activated macrophages, is increased in SDB.

METHODS AND RESULTS

Fifty-five men, free of medical comorbidity, undergoing polysomnography had fasting serum tested for neopterin levels. Multivariable regression methods were used to quantify the association between neopterin and quartiles of the apnea hypopnea index (AHI) while accounting for body mass index, waist circumference, and percentage of body fat. Quartiles of AHI (I: < 3.83 events per hour; II: 3.83 to 11.98 events per hour; III: 11.99 to 36.82 events per hour; IV > 36.82 events per hour) indicated a range from no SDB through severe SDB. Compared to the subjects in the first AHI quartile, serum neopterin levels were higher by 3.0%, 10.9%, and 26.5% in the second, third, and fourth AHI quartiles, respectively (p < 0.001for linear trend). Neopterin levels also were higher in those with greater degree of sleep-related hypoxemia, more stage 1 sleep, and less stage 2 sleep.

CONCLUSION

The results of this study indicate that severity of SDB independently associates with serum levels of neopterin, a marker for macrophage activation that may play an important role in the pathogenesis of SDB-related cardiovascular disease.

Long-term prognostic value of neopterin: a novel marker of monocyte activation in patients with acute coronary syndrome

BACKGROUND

Monocyte activation is believed to play an important role in the pathogenesis of acute coronary syndromes (ACS). Neopterin is a soluble marker of monocyte activation, and elevated levels are of prognostic value in patients with stable coronary artery disease.

METHODS AND RESULTS

Neopterin levels were measured on average at 7 days (in 3946 patients) and at 4 months (in 3369 patients) after ACS in the PRavastatin Or atorVastatin Evaluation Infection Therapy-Thrombolysis In Myocardial Infarction (PROVE IT-TIMI 22) trial. We assessed the relationship between plasma neopterin levels and the risk of death and death or acute coronary events (nonfatal myocardial infarction or unstable angina) over 2 years. Seven days after an ACS event, neopterin levels > or = 12.11 nmol/L (upper quartile, derived from a post hoc analysis) were associated with an increased risk of death and an increased risk of death or acute coronary events after adjustment for age, gender, history of diabetes mellitus, history of hypertension, history of smoking, type of ACS presentation, use of percutaneous coronary intervention for the index event, statin regimen, low-density lipoprotein cholesterol, and high-sensitivity C-reactive protein (hazard ratio, 1.86 [95% CI, 1.24 to 2.77], P=0.003; and hazard ratio, 1.33 [95% CI, 1.09 to 1.63] P=0.006, respectively). Neopterin levels > or = 12.11 nmol/L at 4 months remained a predictor of death alone and of death or acute coronary events after multivariable adjustment that included adjustment for month 4 low-density lipoprotein cholesterol, high-sensitivity C-reactive protein, and statin regimen (hazard ratio, 2.39 [95% CI, 1.43 to 3.99], P=0.001; and hazard ratio, 1.60 [95% CI, 1.21 to 2.11], P=0.001). High-dose atorvastatin significantly attenuated the risk among subjects with neopterin levels > or = 12.11 nmol/L at baseline (interaction P for death or acute coronary event, 0.018).

CONCLUSIONS

Increased monocyte activation detected by an elevated plasma neopterin level identifies patients at long-term risk of death or recurrent acute coronary events after ACS. Intensive statin therapy significantly attenuates the risk of recurrent events among patients with an elevated neopterin level.

Alterations in serum neopterin correlate with thrombolysis in myocardial infarction risk scores in acute coronary syndromes

OBJECTIVES

Using serum neopterin as a marker of macrophage activation, we sought to examine the relationship between serum neopterin levels, thrombolysis in myocardial infarction (TIMI) risk scores, and how different treatments of acute coronary syndromes affect change in neopterin.

METHODS

We examined serum neopterin concentrations at presentation and 72 h after treatment in 70 patients with acute coronary syndromes (35 with medical therapy, 25 with uncoated coronary stents, and 10 received rapamycin-eluting stents) using a commercially available immunoassay. Serum neopterin levels were determined for 36 patients with stable coronary artery disease. TIMI risk scores were calculated when appropriate (n=58).

RESULTS

Serum neopterin had a strong correlation with the TIMI risk score on admission (P<0.0001). The mean baseline neopterin levels in patients with acute coronary syndromes stratified with TIMI scores between 1 and 7 were the following: patients with TIMI 1 scores had a level of 3.3+/-0.4 nmol/l, TIMI 2 patients 4.6+/-0.6 nmol/l, TIMI 3 patients 5.5+/-1.4 nmol/l, TIMI 4 patients 7.5+/-2.4 nmol/l, TIMI 5 patients 10.8+/-3.3 nmol/l, TIMI 6 patients 17.5+/-4.0 nmol/l, and TIMI 7 patients 23.0+/-7.1 nmol/l. Mean changes in serum neopterin were significantly higher for the uncoated stent group than for each of the other three groups (P<0.05).

CONCLUSIONS

Serum neopterin concentrations have a high correlation with TIMI risk scores and may represent a marker useful in stratifying patients with acute coronary syndromes. Our results also suggest that the use of uncoated coronary stents results in macrophage activation not found with other treatment modalities.

[Erectile dysfunction: the role of laboratory in the diagnostic and pronostic evaluation]

OBJECTIVE

To review and to update the different laboratory tests recommended for etiologic diagnostic of erectile dysfunction and to evaluate the effect these tests could have on the pronostic and therapeutic strategy of this pathology.

MATERIAL AND METHODS

We review the last articles related with etiopathogenics and pathophysiologics mechanisms of erectile dysfunction, including our studies on endothelial dysfunction and erectile dysfunction.

RESULTS

The depth and extension of the laboratory protocol in erectile dysfunction is not necessaryly the same in all situations. The age, coincidence of comorbilities, set a different limit between patients demanding complementaries investigations that go beyond the basic request.

CONCLUSIONS

The etiopathogenic laboratory work up in erectile dysfunction is currently changing incorporating news tests. The traditional search of commorbilities like diabetes, hepatic dysfunction, hypogonadism, hyperglucemia is getting broad with recents analitics evaluations related with potential markers of endothelial disease.

The Potential Relevance of the Multiple Lipid-Independent (Pleiotropic) Effects of Statins in the Management of Acute Coronary Syndromes

Emerging data suggest that acute presentations of coronary artery disease may involve a complex interplay between the vessel wall, inflammatory cells, and the coagulation cascade. Although a culprit thrombotic lesion may be treated effectively by antithrombotic therapy and revascularization, this will have little effect on the global processes that determine recurrent events at non-culprit sites. Thus, additional systemic treatment is required to modulate the adverse biological features that are the hallmark of acute coronary syndromes (ACS). Statins possess multiple beneficial effects that are independent of low-density-lipoprotein cholesterol (LDL-C) lowering and that have favorable effects on inflammation, the endothelium, and the coagulation cascade. In the Pravastatin or Atorvastatin Evaluation and Infection Therapy-Thrombolysis In Myocardial Infarction 22 (PROVE IT-TIMI 22) trial, differences were seen based on achieved LDL-C that could be further discriminated by the achieved C-reactive protein level. Studies of non-vascular disease such as multiple sclerosis have shown that statins reduce inflammation, supporting the presence of lipid-independent effects of statins. This review focuses on the potential importance of these effects in the management of ACS.

Mechanism of neopterin-induced myocardial dysfunction in the isolated perfused rat heart

Neopterin is a sensitive marker for diseases involving increased activity of the cellular immune system in humans. Many studies, however, provide evidence for neopterin not only as a marker, but also for its characteristic effects. Recently, we were able to demonstrate a considerable influence of exogenous neopterin at a concentration of 100 mumol/l on cardiac performance in the Langendorff model of isolated perfused rat hearts. The present study was designed to investigate its possible mechanism. During co-infusion of neopterin at a concentration of 100 mumol/l with the unspecific nitric oxide synthase inhibitor N(G)-monomethyl-l-arginine monoacetate, the nitric oxide donor PAPA NONOate, the free radical scavenger N-acetylcysteine, or the pro-inflammatory cytokine tumor necrosis factor-alpha the effects on cardiac contractility parameters and coronary vascular resistance were studied in 67 male Sprague-Dawley rats. The temperature-controlled and pressure-constant Langendorff apparatus was used with retrograde perfusion of the aorta and a Krebs-Henseleit buffer. Neither the unspecific nitric oxide synthase inhibitor nor the nitric oxide donor excludes nitric oxide from playing a mechanistic role in our perfusion studies. Tumor necrosis factor-alpha was without any synergistic or antagonistic effects when co-treated with neopterin. N-acetylcysteine was most effective in abolishing neopterin-dependent effects on cardiac function. The negative effects of neopterin on cardiac performance might be due to an enhancement of oxidative stress by neopterin that can be attenuated by the antioxidant N-acetylcysteine. Neopterin has to be considered a pathogenic factor in the development of cardiac dysfunction in chronic disease states with high neopterin levels secondary to activation of the immune system.

Elevated serum neopterin predicts future adverse cardiac events in patients with chronic stable angina pectoris

AIMS

Serum levels of neopterin, an immune modulator secreted by activated macrophages, are elevated in patients with acute coronary syndromes compared with stable angina patients and control subjects. In unstable angina, serum neopterin levels correlate with the presence of vulnerable coronary stenosis, multiple complex coronary lesions, and patient outcome. The present study assessed the prognostic significance of raised serum neopterin concentrations in patients with stable angina pectoris.

METHODS AND RESULTS

We carried out a 1-year follow-up prospective study in 297 patients with chronic stable chest pain undergoing diagnostic coronary angiography. The primary study endpoint was the composite of non-fatal myocardial infarction, unstable angina, and cardiac death. Fifty-one patients (17.2%) had adverse coronary events during follow-up. Mean serum neopterin levels were significantly higher in patients with events compared with those without (P=0.02). On multiple regression analysis, neopterin levels (P=0.021), severity of coronary artery disease (P=0.009), and a history of previous myocardial infarction (P=0.001) were independent predictors of adverse events.

CONCLUSIONS

Serum neopterin is an independent predictor of major adverse coronary events in patients with chronic stable angina pectoris. This marker of macrophage activation may be useful for risk stratification in patients with chronic stable angina.

Evaluation of serum neopterin, high-sensitivity C-reactive protein and thiobarbituric acid reactive substances in Egyptian patients with acute coronary syndromes

The present study evaluated serum neopterin, high-sensitivity C-reactive protein (hs-CRP) and thiobarbituric acid reactive substances (TBARS) in Egyptian patients with acute coronary artery disease. Thirty-six patients with unstable angina aged (mean +/- SD) 61.3+/-9.4 years, 29 patients with myocardial infarction aged 58.2+/-8.7 years and 24 sex- and age-matched control subjects were included in the study. Neopterin levels were significantly higher in patients with myocardial infarction and those with unstable angina than in the healthy control group (P<0.001). The serum level of neopterin in the control group (median [range]) was 3.25 nmol/L (1.25 nmol/L to 5.4 nmol/L), whereas in patients with unstable angina and those with myocardial infarction, neopterin levels were 10.4 nmol/L (3.5 nmol/L to 15.2 nmol/L) and 12.6 nmol/L (3.25 nmol/L to 17.8 nmol/L), respectively. Levels of hs-CRP and TBARS were also significantly higher in patients with unstable angina and those with myocardial infarction than in the healthy control group (P<0.01). The medians (ranges) of hs-CRP were 4.8 mg/L (2.5 mg/L to 9.9 mg/L), 12.0 mg/L (4.6 mg/L to 31.0 mg/L) and 12.3 mg/L (7.5 mg/L to 32.1 mg/L) in the control group, patients with unstable angina and those with myocardial infarction, respectively. The means +/- SD of TBARS in the control group, patients with unstable angina and those with myocardial infarction were 0.64+/-0.17 mumol/L, 1.17+/-0.31 mumol/L and 1.17+/-0.49 mumol/L, respectively. TBARS positively correlated with hs-CRP and neopterin levels. Furthermore, when both patients and controls were classified according to their smoking status, significantly higher levels of neopterin and TBARS were found in the smokers of each subgroup than in the nonsmokers.In conclusion, the present study found a higher level of neopterin, hs-CRP and TBARS in patients with coronary artery disease. Serum neopterin and hs-CRP positively correlated with the level of TBARS. The authors suggest that triggering factors (eg, smoking, high cholesterol, elevated body mass index or raised blood pressure) may lead to increased oxidative stress, which induces an inflammatory insult leading to higher levels of inflammatory markers such as neopterin and hs-CRP.

Biomarkers of cardiac disease

The challenge of medical practice today is to identify individuals who are at risk of developing disease, determine the severity of the disease and distinguish the responders from the nonresponders to therapy (individualized medicine). Advances in molecular genetics and biology have shifted the paradigm for identification of markers from large-scale epidemiologic studies to studies on genomic- and proteomic-based techniques. Consequently, a large number of biologic markers, referred to as biomarkers, are being identified and validated to serve for risk stratification, prognostication and individualization of therapy. Identification of biomarkers for cardiovascular diseases could also provide insight into the pathogenesis of the phenotype, which is fundamental for the development of specific therapies. The list of biomarkers for cardiovascular disease is expanding rapidly. Nonetheless, the field is in the early stages of evolution and large-scale clinical studies are required to validate the utility of newly identified biomarkers in diagnosis, risk stratification and treatment of cardiovascular diseases. Selected biomarkers for coronary atherosclerosis, acute coronary syndromes and heart failure are discussed in this review.

Markers of Inflammation and Rapid Coronary Artery Disease Progression in Patients With Stable Angina Pectoris

BACKGROUND

Both endothelial cell activation and macrophage activation play a significant role in atherogenesis and atheromatous plaque vulnerability and may determine rapid coronary artery disease (CAD) progression. We sought to assess the association between serum inflammatory markers and rapid CAD progression in patients with chronic stable angina pectoris.

METHODS AND RESULTS

We studied 124 chronic stable angina pectoris patients (84 men; mean age, 61+/-10 years) who were on a waiting list for coronary angioplasty for a mean time of 4.8+/-2.4 months. CAD progression was defined as > or =10% diameter reduction of a pre-existing stenosis > or =50%, > or =30% diameter reduction of a stenosis <50%, development of a new stenosis > or =30% in a previously normal segment, or progression of any stenosis to total occlusion. CAD progression occurred in 35 patients (28%). After adjustment with binary logistic regression, neopterin (P<0.001), high-sensitivity C-reactive protein (P=0.017), matrix metalloproteinase-9 (P=0.002), soluble intercellular adhesion molecule 1 (P<0.001), and previous history of unstable angina (P=0.01) were independent predictors of rapid CAD progression. The association between rapid disease progression and inflammatory markers remained significant even when presence of complex lesions was introduced into the multivariate model.

CONCLUSIONS

Rapid CAD progression in patients with stable angina pectoris is associated with increased C-reactive protein levels and raised concentrations of biochemical markers of endothelial and macrophage activation.

HMG-CoA reductase inhibitors are associated with decreased serum neopterin levels in stable coronary artery disease

Neopterin, a marker of stimulated cellular immune response, is increased in unstable angina, acute myocardial infarction and possibly stable coronary artery disease. 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) have anti-inflammatory properties, but their effect on neopterin is largely unknown. Neopterin was measured in 232 patients undergoing elective coronary angiography and compared to the degree of atherosclerosis, use of concomitant medications and demographics. Neopterin was lower in subjects using statins (n = 66) compared to those not taking statins (median (range): 6.65 (4.1-18.3) vs. 7.70 (3.6-29.1) nmol/l, p < 0.0001). This association was also found in the subgroup of patients with coronary artery disease (1-3-vessel disease, n = 164; 6.60 (4.1-18.3) vs. 7.80 (3.6-29.1) nmol/l, p = 0.0012), whereas only a slight tendency toward lower neopterin levels was found in the group without atherosclerosis (6.90 (5.1-16.0) vs. 7.60 (4.0-18.5) nmol/l, p = 0.17). In patients with coronary atherosclerosis, neopterin concentrations were lower in smokers (n = 105) compared to non-smokers (7.20 (3.6-29.1) vs. 7.90 (4.4-18.6) nmol/l, p < 0.02), confirming previous observations. However, use of statins was associated with lower neopterin levels in both non-smokers and smokers (6.70 (4.1-18.3) vs. 7.60 (3.6-29.1) nmol/l, p < 0.05, and 6.20 (5.2-16.0) vs. 7.80 (4.4-18.6) nmol/l, p < 0.05, respectively). Overall, similar serum neopterin concentrations were found in patients with coronary atherosclerosis and those without. In accordance with their anti-inflammatory effects, the use of statins is associated with lower neopterin levels in patients undergoing elective coronary angiography.

Prognostic value of neopterin levels in treated patients with hypertension and chest pain but without obstructive coronary artery disease

We sought to assess the relation between circulating levels of inflammation markers, such as neopterin and C-reactive protein, and the development of adverse cardiovascular events in patients with hypertension but without obstructive coronary artery disease. We observed that patients who developed adverse events during follow-up had significantly higher neopterin levels compared with patients without events.

Usefulness of elevated neopterin and C-reactive protein levels in predicting cardiovascular events in patients with non-Q-wave myocardial infarction

The value of monocyte/macrophage activity as a prognostic factor in patients with non-Q-wave myocardial infarction (NQMI) has not yet been investigated. Moreover, scarce data are available on the long-term predictive value of markers of inflammation in patients who experience a NQMI. The present study aimed to determine the predictive value of neopterin, alone and in relation to levels of C-reactive protein, on the recurrence of major clinical cardiovascular events in patients who had a NQMI.

Neopterin levels in patients with coronary artery disease are independent of Chlamydia pneumoniae seropositivity

BACKGROUND

Chronic infection with Chlamydia pneumoniae (Cpn) has been associated with atherosclerotic cardiovascular disease in sero-epidemiological, pathological and animal-model studies. Inflammation and immune activation has been proposed as the pathophysiological link between chronic infection and atherosclerosis. The aim of this study was to assess whether Cpn seropositivity is associated with serum neopterin concentrations, a marker of macrophage activation, in patients with stable and unstable angina pectoris.

METHODS

We examined 100 patients with angiographically documented coronary artery disease: 60 patients had chronic stable angina and 40 had Braunwald class III unstable angina. Neopterin concentrations were measured with a commercially available immunoassay. Cpn titres were measured with a microimmunofluorescence (MIF) assay.

RESULTS

Neopterin concentrations were significantly higher in patients with unstable angina compared to those with chronic stable angina (6.30 [4.85-8.80] nmol/L vs 4.95 [3.35-7.05] nmol/L, P =.004), even after adjustment for variables that were significantly different between the 2 groups on univariate analysis. In contrast, the prevalence of positive Cpn serology did not differ significantly between the 2 angina patient groups (65% v 58%, P =.50). Neopterin levels were similar between Cpn-negative and Cpn-positive patients (P =.40) in both stable and unstable angina groups.

CONCLUSIONS

Patients with unstable angina had higher neopterin concentrations than patients with chronic stable angina, probably reflecting the higher degree of immune activation in acute coronary syndromes. Neopterin levels, however, were independent of Cpn serostatus when combining both stable and unstable angina patients. Thus, immune activation in patients with acute coronary syndromes appears to be unrelated to Cpn seropositivity.

Serum neopterin and activity of coronary artery disease

Inflammation plays a key role in the pathogenesis of atherosclerosis. In coronary artery disease (CAD), the release of different cytokines activates cellular defense. Infiltration of neutrophils and monocytes/macrophages is detected in the vessel wall in patients with CAD. Macrophages activated by interferon gamma synthesize metalloproteinases and neopterin, a pteridin derivative that has been used as an immune marker. To determine neopterin levels in patients with chronic CAD and acute coronary syndromes, the authors studied 116 subjects: 1) 25 consecutive patients (18 men, 7 women; mean age 68.5 +/- 14.3, range 40 to 86 years) with unstable angina or acute myocardial infarction (AMI); 2) 31 consecutive patients (25 men, 6 women; mean age 64 +/- 12.7, range 47 to 83 years) with signs and symptoms of clinically stable CAD; and 3) 60 consecutive healthy blood donors (38 men, 22 women; mean age 54.4 +/- 6.23, range 44 to 66 years). Neopterin levels were determined with a commercially available enzyme-linked immunosorbent assay method. In patients with unstable angina and AMI before thrombolytic therapy, neopterin levels were not significantly different from levels in patients with stable CAD (5.97 +/- 1.4 versus 7.84 +/- 3.56 nmol/L; P = 0.15). Neopterin levels in both patient groups did not significantly differ from levels in control subjects (P > 0.1). Neopterin levels in patients with unstable angina and AMI were measured four times during a 72-hour period. The lowest value was observed at baseline and differed significantly from values after 72 hours (P < 0.001; 5.97 +/- 1.4 versus 9.25 +/- 2.36). Neopterin levels after 72 hours were also significantly different from initial values in patients with stable CAD (P < 0.001). There was no correlation between neopterin and creatine kinase (CK) levels, CK-MB isoenzyme, or troponin I as markers for the extent of the myocardial injury during the observation period. These data do not support previous reports of higher baseline levels of serum neopterin in patients with unstable angina or AMI compared with patients with chronic, stable CAD and healthy controls. Neopterin as a marker of macrophage activation is significantly increased in patients with AMI and unstable angina shortly after the onset of symptoms (after a period of 72 hours), supporting the hypothesis of monocyte and macrophage activation in patients with an acute coronary syndrome or AMI.

Association between homocysteine and neopterin in healthy subjects measured by a simple HPLC-fluorometric method

OBJECTIVES

Neopterin and homocysteine promote vascular smooth muscle cell proliferation through the activation of nuclear factor(kappa) B. The aim of this study was to investigate the relation between these two compounds in healthy subjects by a rapid HPLC-fluorometric method which simplifies sample pretreatment for the measurement of neopterin in serum.

DESIGN AND METHODS

In 40 healthy subjects (45.9 +/- 2.1 yr, mean +/- SEM, 10 males, 30 females) serum neopterin concentrations were measured by HPLC-fluorometry and enzyme-linked immunusorbant assay-ELISA and the results were compared. Urinary neopterin and plasma total homocysteine concentrations were assayed by HPLC-fluorometry.

RESULTS

Serum neopterin concentrations measured by HPLC and ELISA were 7.5 +/- 0.4 and 7.4 +/- 0.3 nmol/L, respectively, r = 0.92, p < 0.01. Urinary neopterin level was 163.9 +/- 11.0 nmol/mmol creatinine and plasma total homocysteine 7.6 +/- 0.4 micromol/L. A significant positive correlation was observed between serum neopterin and plasma total homocysteine (r = 0.59, p < 0.01).

CONCLUSIONS

A simple and rapid sample pretreatment for the measurement of neopterin in serum has been introduced. The significant positive correlation between neopterin and homocysteine implies that, interference with leukocyte function might be a new possible mechanism for the deleterious effects of homocysteine on vascular function.