Neopterin predicts left ventricular remodeling in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

Neopterin derivatives - a novel therapeutic target rather than biomarker for atherosclerosis and related diseases

This review provides an updated overview of the emerging roles of neopterin derivatives in atherosclerosis. Neopterin, a metabolite of guanosine triphosphate, is produced by interferon-γ-activated macrophages and is expressed at high levels in atheromatous plaques within the human carotid and coronary arteries as well as in the aorta. Plasma concentrations of neopterin are higher in patients with carotid, cerebral, and coronary artery diseases as well as aortic aneurysm. The concentration of neopterin is positively correlated with the severity of coronary artery disease. However, a prospective cohort study showed that neopterin contributes to protection against plaque formation in carotid arteries in patients with atherosclerosis. Moreover, using both in vitro and in vivo experiments, a recent study has shown the atheroprotective effects of neopterin. Neopterin suppresses the expression of monocyte chemotactic protein-1, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 in endothelial cells, and thereby suppresses the adhesion of monocytes to endothelial cells. It also suppresses the inflammatory phenotype of monocyte-derived macrophages. In addition, neopterin suppresses oxidized low-density lipoprotein-induced foam cell formation in macrophages and the migration and proliferation of vascular smooth muscle cells. Neopterin injection into apolipoprotein E-deficient (Apoe^-/-) mice suppresses the development of atherosclerotic lesions. A neopterin derivative tetrahydroneopterin (BH4), also known as a cofactor for nitric oxide (NO) synthases, suppresses atherosclerosis and vascular injury-induced neointimal hyperplasia in Apoe^-/- mice. BH4 administration improves endothelial dysfunction in patients with coronary artery disease. These findings suggest that neopterin production may increase to counteract the progression of atherosclerosis, as neopterin contributes to atheroprotection. Otherwise, the increased neopterin levels in atherosclerosis may reflect a compensatory mechanism associated with inducible NO synthase upregulation in macrophages to supply BH4 for high output NO production caused by decreased endothelial NO synthase in atherosclerosis. Therefore, neopterin derivatives are a novel therapeutic target for atherosclerosis and related diseases.

Safety, tolerability, pharmacokinetics and pharmacodynamics of parenterally administered dutogliptin: A prospective dose-escalating trial

Aims

Animal studies suggest that inhibition of dipeptidyl peptidase 4 (DPP‐IV) may improve heart function and survival after myocardial infarction by increasing cardiac myocytes’ regenerative capacity. Parenterally administered dutogliptin may provide continuous strong DPP‐IV inhibition to translate these results into humans. This trial investigated the safety and tolerability, as well as pharmacokinetics and pharmacodynamics, of parenterally administered dutogliptin after single and repeated doses.

Methods

In an open‐label trial, volunteers received dutogliptin at increasing doses of 30–120 mg subcutaneously or 30 mg intravenously in the single‐dose cohorts. Subjects in the multiple‐dose cohort received 60, 90 or 120 mg dutogliptin subcutaneously once daily on 7 consecutive days.

Results

Forty healthy males were included in the trial. No related serious adverse events occurred. Mild local injection site reactions with no requirement for intervention comprised 147 of 153 (96%) related adverse events. Subcutaneous bioavailability was approximately 100%. Multiple injections at daily intervals did not lead to the accumulation of the study drug. The accumulation ratios based on AUC_0‐24h range from 0.90 to 1.03, supporting this argument. All subjects receiving ≥60 mg dutogliptin yielded a maximum DPP‐IV inhibition >90%. The duration of DPP‐IV inhibition over time increased in a dose‐dependent manner and was highest in the 120‐mg multiple‐dosing cohort with a maximum AUEC_0‐24h of 342 h % (standard deviation: 73), translating into 86% DPP‐IV inhibition 24 hours after dosing.

Conclusion

Parenteral injection of dutogliptin was safe and subcutaneous bioavailability is excellent. DPP‐IV inhibition increased dose dependently to >86% over 24 hours after multiple doses of 120 mg dutogliptin.

Neopterin and Cardiovascular Events Following Coronary Stent Implantation in Patients with Stable Angina Pectoris

AIM

Neopterin is an activation marker for monocytes/macrophages. We prospectively investigated the predictive value of plasma neopterin levels on 2-year and long-term cardiovascular events in patients with stable angina pectoris (SAP) undergoing coronary stent implantation.

METHODS

We studied 123 consecutive patients with SAP who underwent primary coronary stenting (44 patients with bare metal stent: BMS group and 79 with drug-eluting stent: DES group). Plasma neopterin levels were measured on admission using HPLC. Moreover, one frozen coronary artery specimen after DES and three frozen coronary specimens after BMS were obtained by autopsy or endarterectomy, followed by immunohistochemical staining for neopterin.

RESULTS

Plasma neopterin levels were significantly higher in patients with cardiovascular events than in those without them (P＜0.001). In subgroup analyses, higher levels of plasma neopterin in patients with cardiovascular events (P＜0.001) and a positive correlation between neopterin levels and late lumen loss after stenting (P =0.008) were observed in the BMS group but not in the DES group (P=0.53 and P=0.17, respectively). In long-term cardiovascular events, multivariate Cox regression analysis identified the significance of the high-neopterin group as independent determinants of cardiovascular events (hazard ratio, 2.225; 95% CI, 1.283-3.857; P =0.004). Immunohistochemical staining showed abundant neopterin-positive macrophages in the neointima after BMS implantation but no neopterin-positive macrophages in the neointima after DES implantation.

CONCLUSION

These findings suggest that neopterin is associated with cardiovascular events after coronary stent implantation in patients with SAP. However, there might be a strong association between neopterin and cardiovascular events after BMS but not after DES in these patients.

Combined biomarker testing for the prediction of left ventricular remodelling in ST-elevation myocardial infarction

Objective

The utility of different biomarkers for the prediction of left ventricular remodelling (LVR) following ST-elevation myocardial infarction (STEMI) has been evaluated in several studies. However, very few data exist on the prognostic value of combined biomarkers. The aim of this study was to comprehensively investigate the prognostic value for LVR of routinely available biomarkers measured after reperfused STEMI.

Methods

Serial measurements of N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity cardiac troponin T (hs-cTnT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and high-sensitivity C reactive protein (hs-CRP) were performed in 123 patients with STEMI treated with primary percutaneous coronary intervention in this prospective observational study. Patients underwent cardiac MRI at 2 (1–4) and 125 (121–146) days after infarction. An increase in end-diastolic volume of ≥20% was defined as LVR.

Results

LVR occurred in 16 (13%) patients. Peak concentrations of the following biomarkers showed significant areas under the curves (AUCs) for the prediction of LVR—NT-proBNP: 0.68 (95% CI 0.59 to 0.76, p=0.03), hs-cTnT: 0.75 (95% CI 0.66 to 0.82, p<0.01), AST: 0.72 (95% CI 0.63 to 0.79, p<0.01), ALT: 0.66 (95% CI 0.57 to 0.75, p=0.03), LDH: 0.78 (95% CI 0.70 to 0.85, p<0.01) and hs-CRP: 0.63 (95% CI 0.54 to 0.72, p=0.05). The combination of all biomarkers yielded a significant increase in AUC to 0.85 (95% CI 0.77 to 0.91) (all vs NT-proBNP: p=0.02, all vs hs-cTnT: p=0.02, all vs AST: p<0.01, all vs ALT: p<0.01, all vs hs-CRP: p<0.01 and all vs LDH: p=0.04).

Conclusions

In patients with reperfused STEMI, the combined assessment of peak NT-proBNP, hs-cTnT, AST, ALT, hs-CRP and LDH provide incremental prognostic information for the prediction of LVR when compared with single-biomarker measurement.

Neopterin and interleukin-6 as predictors of recurrent atrial fibrillation

OBJECTIVE

Available evidence suggests that inflammation may be associated with atrial fibrillation (AF). This prospective and observational study aimed to assess whether plasma neopterin (NPT) and interleukin-6 (IL-6) levels before and after electrical cardioversion (CV) predict AF recurrence.

METHODS

The study was designed as a prospective observational trial. Blood samples were collected (24 hours before, 24 h after CV, and 7 days after CV) in 60 patients with a dual-chamber pacemakar and preserved left ventricular systolic function who underwent successful CV of persistent AF. All significant parameters associated with AF recurrence lasting ≥30 min and detected by pacemaker data logs were evaluated in multivariate logistic regression analysis. Echocardiography was performed 7 days after CV in patients with sinus rhythm. The control group included 17 subjects without AF.

RESULTS

The analysis included 51 patients who remained in sinus rhythm 7 days after CV. During 12 months of follow-up, AF recurred in 46 patients. Baseline IL-6 levels did not differ between the two groups, but baseline NPT levels were higher in the study group than in the control group (19±7 vs. 11±5 nmol/mL, p<0.001). NPT levels of ≥14.6 nmol/L at baseline and ≥13.3 nmol/L 7 days after CV separated the patients with AF recurrence from those without arrhythmia after CV. Only left atrial emptying fraction <38% was an independent predictor of AF recurrence (p=0.03), whereas NPT levels of ≥13.3 nmol/L 7 days after CV showed borderline statistical significance (p=0.07).

CONCLUSION

Increased NPT level was observed in patients with persistent AF. Neither baseline IL-6 and NPT levels nor their changes within 7 days after CV were predictive of AF recurrence. Further studies are needed to establish the prognostic significance of NPT in patients with AF.

Prognostic value of pentraxin-3 level in patients with STEMI and its relationship with heart failure and markers of oxidative stress

OBJECTIVE

Pentraxin-3 (PTX3) appears to have a cardioprotective effect through a positive influence against postreperfusion damage. This study assesses the prognostic value of PTX3 level and its relationship with clinical parameters and markers of oxidative stress and nitric oxide metabolism in patients with ST-elevation myocardial infarction (STEMI).

METHODS

Plasma/serum levels of several biomarkers of inflammation and oxidative stress and nitrite/nitrate were assessed upon admission and 24 h after STEMI onset in patients treated by primary percutaneous coronary intervention.

RESULTS

ROC analysis showed that plasma PTX3 at 24 h was a strong predictor of 30-day and 1-year mortality and independent predictor of combined end-point of left ventricle dysfunction or mortality in 1 year. The inflammatory response expressed by PTX3 had a significant relationship with age, heart failure, infarct size, impaired flow in the infarct-related artery, and renal function and positively correlated with neopterin, TNF-α, 8-hydroxy-2'-deoxyguanosine, and nitrite/nitrate.

CONCLUSIONS

Plasma PTX3 at 24 h after STEMI onset is a strong predictor of 30-day and 1-year mortality. PTX3 as a single biomarker is comparable with currently used scoring systems (TIMI or GRACE) or B-type natriuretic peptide. PTX3 is also an independent predictor of combined end-point of left ventricle dysfunction or mortality in 1 year.

Decreased level of melatonin in serum predicts left ventricular remodelling after acute myocardial infarction

As experimental studies suggest that melatonin is cardioprotective after myocardial infarction (MI), this study sought to investigate the relationships between circulating levels of melatonin and left ventricular (LV) remodelling in patients after acute MI. This prospective study included 161 patients (age 61±3yr; 78% men) undergoing primary percutaneous coronary intervention who were assessed echocardiographically at hospital discharge (day 3-7) and at 12 months. LV remodelling was defined as >20% increase in LV end-diastolic volume at 12-month follow-up compared with baseline. Serum melatonin concentrations were measured at admission, during the light period. Twenty-four patients showed LV remodelling, and 137 had no evidence of LV remodelling. Patients with LV remodelling had lower levels of melatonin at study entry [9.96 (8.28-11.03) versus 16.74 (13.77-19.59) pg/mL, respectively; P <0.0001]. Multivariate analysis showed that melatonin levels (OR=2.10, CI 95% 1.547-2.870, P<0.001) were an independent predictor of LV remodelling at 12-month follow-up. Receiver operating characteristic (ROC) analysis showed an area under the curve of 0.959 (CI 95% 0.93-0.98; P<0.0001). To our knowledge, this is the first study to show the relationship between melatonin and LV remodelling during the chronic phase post-MI.

Usefulness of circulating biomarkers for the prediction of left ventricular remodeling after myocardial infarction

Left ventricular (LV) remodeling after myocardial infarction (MI) indicates a high risk of heart failure and death, but LV remodeling remains difficult to predict. Biomarkers may help to refine risk stratification for a more personalized medical approach. They may also shed light on the pathophysiologic processes involved. We performed a systematic review of the published evidence about the association of circulating biomarkers with LV remodeling after MI. We selected 59 publications. Overall, these studies examined 112 relations between 52 different biomarkers and LV remodeling. The biomarkers most consistently associated with LV remodeling were involved in extracellular matrix turnover or neurohormonal activation: matrix metalloproteinase-9, collagen peptides, and B-type natriuretic peptide. This review underscores the vitality of the research on LV remodeling but concludes that the ideal biomarker has not yet been identified. To reach this goal, future studies will have to be larger, have standardized imaging end points, and include replication populations to define optimal cutoffs for LV remodeling prediction. Cardiovascular magnetic resonance appears to be the best technique for LV remodeling assessment but its current availability may be a concern for recruitment for multicenter studies. Recent technologic advances will probably yield new candidate biomarkers of LV remodeling. Tests are necessary to determine whether a multimarker approach would significantly improve risk prediction.

Usefulness of serum neopterin levels in acute decompensated heart failure to predict renal dysfunction

CONTEXT

Neopterin serum concentration increases in the presence of renal dysfunction.

OBJECTIVE

We sought to determine the relationship between admission serum neopterin levels and worsening renal function (WRF) in patients with heart failure (HF).

METHODS

We prospectively measured serum neopterin levels in patients with HF and the patients were subdivided into two groups: with and without WRF during hospital admission.

RESULTS

Logistic regression analysis showed that high serum neopterin levels at admission were associated with a greater likelihood of developing WRF.

CONCLUSIONS

Patients admitted to hospital with HF, elevated serum neopterin levels are associated with an increased risk of developing WRF.