Usefulness of pregnancy-associated plasma protein A in patients with acute coronary syndrome

Risk Assessment after ST-Segment Elevation Myocardial Infarction: Can Biomarkers Improve the Performance of Clinical Variables?

INTRODUCTION

Myocardial infarction with ST-segment elevation (STEMI) is the coronary artery disease associated with the highest risk of morbimortality; however, this risk is heterogeneous, usually being evaluated by clinical scores. Risk assessment is a key factor in personalized clinical management of patients with this disease.

AIM

The aim of this study was to assess whether some new cardiac biomarkers considered alone, combined in a multibiomarker model or in association with clinical variables, improve the short- and long-term risk stratification of STEMI patients.

MATERIALS AND METHODS

This was a retrospective observational study of 253 patients with STEMI. Blood samples were obtained before or during the angiography. The assessed biomarkers were C-terminal fragment of insulin-like growth factor binding protein-4 (CT-IGFBP4), high sensitive cardiac troponin T (hs-cTnT), N-terminal fragment of probrain natriuretic peptide (NT-proBNP), and growth differentiation factor 15 (GDF-15); they reflect different cardiovascular (CV) physiopathological pathways and underlying pathologies. We registered in-hospital and follow-up mortalities and their causes (cardiovascular and all-cause) and major adverse cardiac events (MACE) during a two year follow-up. Discrimination, survival analysis, model calibration, and reclassification of the biomarkers were comprehensively evaluated.

RESULTS AND DISCUSSION

In total, 55 patients (21.7%) died, 33 in-hospital and 22 during the follow-up, most of them (69.1%) from CV causes; 37 MACE occurred during follow-up. Biomarkers showed good prognostic ability to predict mortality, alone and combined with the multibiomarker model. A predictive clinical model based on age, Killip-Kimball class, estimated glomerular filtration rate (eGFR), and heart rate was derived by multivariate analysis. GDF-15 and NT-proBNP significantly improved risk assessment of the clinical model, as shown by discrimination, calibration, and reclassification of all the end-points except for all-cause mortality. The combination of NT-proBNP and hs-cTnT improved CV mortality prediction.

CONCLUSIONS

GDF-15 and NT-proBNP added value to the usual risk assessment of STEMI patients.

Pregnancy associated plasma protein-A as a prognostic biomarker of all-cause mortality and cardiovascular events in patients presenting with chest pain: a systematic review

AIM

Novel biomarkers have been proposed for identification of patients at greater risk of future adverse events among those presenting with chest pain. In this review, we aim to elucidate the ability of pregnancy associated plasma protein-A (PAPP-A) to predict mortality and other cardiovascular events in this patient population.

METHODS

A literature search of the electronic databases Medline, Scopus, Cochrane Library and ClinicalTrials.gov was performed in order to identify studies investigating the utility of PAPP-A to predict mortality and adverse cardiovascular events in patients with chest pain.

RESULTS

Eight studies met our inclusion criteria. Five of these studies pertained to patients with confirmed ischemic chest pain, while the rest included patients presenting with chest pain possibly due to acute coronary syndrome, irrespectively of the underlying cause. Although the results for long-term events were inconclusive in both groups of patients, higher PAPP-A concentrations were found to be a significant predictor of short-term adverse events in patients with confirmed ischemic chest pain.

CONCLUSIONS

PAPP-A appears to be a potentially useful biomarker for short-term risk stratification of patients presenting with chest pain of ischemic origin. However, there is an eminent need for more standardized clinical studies investigating the prognostic value of this biomarker.

Pregnancy-associated plasma protein-A is a stronger predictor for adverse cardiovascular outcomes after acute coronary syndrome in type-2 diabetes mellitus

Background

The risk prediction of pregnancy-associated plasma protein-A (PAPP-A) for future cardiovascular (CV) events post acute coronary syndrome (ACS) in patients with type-2 diabetes mellitus (T2DM) was investigated in comparison to other risk factors.

Methods

PAPP-A was measured at hospital admission in 320 consecutive ACS patients (136 with T2DM and 184 without). All patients were followed for 2 years for occurrence of CV death, non-fatal MI or stroke. Effect of PAPP-A on the CV event risk was estimated using Cox regression models. Receiver operating characteristics (ROC) curves were generated to demonstrate the sensitivity and specificity of PAPP-A in predicting CV events.

Results

ACS patients with T2DM had higher PAPP-A (19.29 ± 16.36 vs. 13.29 ± 13.90 ng/ml, p < 0.001) and higher rate of CV events 2 years post ACS (27.2 vs. 13.6%, p = 0.002) than those without. Higher levels of PAPP-A were significantly associated with increased risk of CV events during 2-year follow-up [HR = 2.97 for 1 SD increase in log₁₀(PAPP-A), 95% CI 2.11–4.18, p < 0.001] in T2DM and (HR = 3.16, 95% CI 2.27–4.39, p < 0.001) in non-T2DM. Among patients with T2DM, PAPP-A showed a larger area under the curve (AUC 0.79) that was significantly more predictive than hsCRP (AUC 0.64), eGFR (AUC 0.66) and LVEF < 50% (AUC 0.52); predictive ability did not improve significantly by including those factors into the model.

Conclusions

Patients with T2DM had higher levels of PAPP-A and increased risk of CV events. Elevated PAPP-A compared to other risk factors was a stronger predictor for future CV events 2 years post ACS in patients with T2DM.

Trial registration ISRCTN10805074. Registered on 20 January 2017, retrospectively registered.

Can pregnancy-associated plasma protein-A be a marker for the assessment of atherosclerosis risk in patients with chronic plaque psoriasis?

Introduction

Psoriasis is an immune-mediated chronic inflammatory dermatosis. Several studies have shown that patients with psoriasis have a much greater risk of cardiovascular diseases than the normal population. The chronic inflammation observed in psoriasis is thought to have a role in the development of atherosclerosis and vascular endothelial injury.

Aim

To examine serum pregnancy-associated plasma protein-A (PAPP-A) levels, which has been regarded as a marker of early stage atherosclerosis in patients with psoriasis that do not have concurrent conventional cardiovascular risk markers.

Material and methods

Forty-one patients diagnosed with a chronic plaque type of psoriasis and 42 equally matched healthy volunteers were included in this study. The PAPP-A levels were compared between patient and control groups and the association between PAPP-A levels and disease duration and severity were evaluated in the patient group.

Results

Statistically, serum PAPP-A levels were significantly higher in the psoriasis group than in the control group (p = 0.015). Serum PAPP-A levels were found to be positively correlated with severity (p = 0.036, r = 0.329) and duration (p = 0.014, r = 0.269) of the disease.

Conclusions

As a marker of early stage atherosclerosis, PAPP-A levels were elevated in the psoriasis group and were correlated with disease duration and severity. This elevation reveals the presence of atherosclerosis in patients with psoriasis. Further studies are needed to confirm the use of PAPP-A as an available and inexpensive screening test and cardiovascular risk assessment for all centers.

Pregnancy-associated plasma protein-A (PAPP-A) as a possible biomarker in patients with coronary artery disease

BACKGROUND

Cardiovascular disease is the leading cause of death in the Western world, and a major cause of this disease is atherosclerosis. Research has demonstrated that pregnancy-associated plasma protein A (PAPP-A) plays a role in cardiovascular disease, as evidenced by the association between PAPP-A and severity of heart damage.

AIM

The aim of this work was to investigate the correlation between PAPP-A concentrations in coronary and peripheral blood and certain clinicopathological factors and antioxidant enzyme activities in patients diagnosed with coronary artery disease.

METHODS

For 65 patients, arterial blood was obtained by puncturing the femoral or radial artery, and coronary blood was obtained via percutaneous coronary intervention. PAPP-A, catalase (CAT), superoxide dismutase-1 (SOD-1), and superoxide dismutase-2 (SOD-2) levels were measured using spectrometric methods.

RESULTS

Coronary PAPP-A levels were slightly higher than peripheral PAPP-A levels (81.25 ± 2.34 and 62 ± 3 ng/mL, respectively, P < 0.0001); these levels were correlated with each other (r = 0.6629, P < 0.001) but not with clinicopathological factors (P > 0.05). Coronary PAPP-A levels were significantly elevated among patients at risk for cardiovascular disease (P < 0.05). Antioxidant enzyme activities were significantly higher in coronary samples than in peripheral samples from subjects with ischemic cardiopathy secondary to atherosclerosis (P < 0.001). Neither coronary nor peripheral PAPP-A levels were correlated with antioxidant enzyme activities in patients with cardiopathy secondary to atherosclerosis (P > 0.05).

CONCLUSIONS

PAPP-A levels could be used as biomarkers to identify patients at risk of coronary artery disease.

Pregnancy-associated plasma protein-A and the vulnerable plaque

For more than a decade, pregnancy-associated plasma protein-A (PAPP-A) has been examined for its relation to acute coronary syndrome (ACS) and the vulnerable plaque. This review summarizes the current knowledge of plasma PAPP-A in relation to nonpregnant individuals focusing on patients with ACS, discusses its use as a possible biomarker for diagnosis and prognosis in ACS, briefly describes the challenges in different assay technologies and describes the effect of heparin administration on PAPP-A concentrations in plasma.

The effect of heparin on pregnancy associated plasma protein-A concentration in healthy, non-pregnant individuals

OBJECTIVES

The objective of this study was to determine the differences in pregnancy associated plasma protein-A (PAPP-A) concentrations in heparin naive and heparin treated healthy men and non-pregnant women, to find a possible difference in different age groups, and to determine the response in PAPP-A concentration to repeated injections of unfractionated heparin.

DESIGN AND METHODS

Twenty-five healthy, non-pregnant volunteers divided into five groups (determined by gender and age) received 5000 IU unfractionated heparin intravenously. Five young men received an additional 5000 IU after 90 and 180 min. Blood samples to determine PAPP-A concentration and APTT were drawn at different time points.

RESULTS

Injection of heparin elicited increase in and rapid normalization of PAPP-A concentrations in all subjects. The group of 20-30-year-old never-pregnant women had lower responses than the individuals of the four other groups. The difference was not significant (p > 0.05). Repeated injections of heparin caused additional peaks in PAPP-A concentration of about the same sizes as the first peak. We observed an increase in time to normalization of PAPP-A concentration (from 75-90 min to 90-150 min) and APTT levels with repeated injections.

CONCLUSIONS

We observed a rapid normalization of PAPP-A. Our result has a great similarity to the half-life of unfractionated heparin. This result combined with the finding of equally sized peaks in PAPP-A concentration, and that all of this was found in healthy, non-pregnant individuals, suggests that heparin might compete for a binding-site on PAPP-A or with PAPP-A itself for a common receptor in healthy arterial vessels.

Pregnancy Associated Plasma Protein-A (PAPP-A) Levels in Acute Coronary Syndrome: A Case Control Study in a Tertiary Care Centre

In recent years, an important objective of cardiovascular research has been to find new markers that would improve the risk stratification and diagnosis of patients presenting with symptoms of acute coronary syndrome (ACS). Established biomarkers for diagnosis of ACS includes troponins and creatine kinase MB (CK-MB). Pregnancy associated plasma protein A (PAPP-A) is an emerging marker which has been described as a marker of plaque instability. PAPP-A is a large metalloproteinase involved in insulin-like growth factor signaling and has been shown to be involved in pathological processes like atherosclerosis. Many studies have been published regarding release of PAPP-A in circulation during ACS. The objective of this study was to evaluate the role of PAPP-A as an early marker of ACS by comparing levels of PAPP-A in patients with acute myocardial infarction (AMI) and unstable angina (UA) with asymptomatic controls. The association of PAPP-A with markers of myocardial necrosis and the association of PAPP-A levels to the presence of risk factors for coronary artery disease was also studied. We measured PAPP-A levels in patients with AMI (30), UA (23) and asymptomatic controls (45). PAPP-A was estimated using PAPP-A US (ultra sensitive) ELISA manufactured by DRG (Germany). PAPP-A levels were significantly elevated in patients with AMI and in patients with UA (mean levels 64.26 ± 1.05 and 36.23 ± 1.05 ng/ml respectively; p < 0.001). Mean PAPP-A levels in controls were 10.68 ± 1.04 ng/ml. In UA cases PAPP-A levels were elevated when the troponin I and CK-MB levels were within the normal range. No correlation was observed between PAPP-A with markers of myocardial necrosis. PAPP-A can serve as a useful biomarker in the diagnosis of ACS, especially UA, where cardiac troponin levels and CK-MB levels are not elevated and ECG changes are inconclusive.

Longitudinal changes in C-reactive protein, proform of eosinophil major basic protein, and pregnancy-associated plasma protein-A during weight changes in obese children

BACKGROUND

Childhood obesity is associated with several complications, including cardiovascular comorbidity. Several biomarkers, such as high-sensitive C-reactive protein (hs-CRP), proform of eosinophil major basic protein (Pro-MBP) and pregnancy associated plasma protein-A (PAPP-A), have equally been linked to increased cardiovascular susceptibility. This study investigates these biomarkers during weight loss and regain in obese children.

MATERIALS AND METHODS

A longitudinal study during a 12-week weight loss program with a 28 months follow-up was conducted. Anthropometrics and plasma concentrations of hs-CRP, Pro-MBP, and PAPP-A were measured at baseline; at days 14, 33 and 82 during weight loss; and at months 10, 16, and 28 during follow-up.

RESULTS

Fifty-three boys and 62 girls aged 8-15 years with a median body mass index (BMI) standard deviation score (SDS) at baseline of 2.78 (boys), and 2.70 (girls) were included. Ninety children completed the weight loss program and 68 children entered the follow-up program. Pro-MBP and PAPP-A, but not hs-CRP, exhibited individual-specific levels (tracking) during weight loss and regain. The PAPP-A/Pro-MBP correlation was strong, whereas the hs-CRP/PAPP-A correlation was weak during weight fluctuations.

CONCLUSION

Hs-CRP changes reflect weight changes. PAPP-A and Pro-MBP exhibited tracking during weight perturbations and may contribute as early risk markers of cardiovascular susceptibility.

Beyond cardiac troponin: recent advances in the development of alternative biomarkers for cardiovascular disease

Biomarkers complement clinical assessment, electrocardiogram and cardiac imaging in the diagnosis, risk stratification, triage and management of patients with suspected acute cardiovascular diseases. While there is broad consensus that cardiac troponin is the preferred biomarker in clinical practice for the detection of cardiomyocyte damage, the role of alternative biomarkers is less clear. In fact, despite high quality basic and clinical research by hundreds of groups worldwide, only a single new alternative cardiovascular biomarker (natriuretic peptides) has managed to achieve widespread clinical acceptance and inclusion in contemporary clinical practice guidelines in the last decade. This review aims to discuss the remaining unmet needs (and hence opportunities for new biomarkers) in two major clinical areas: early diagnosis of acute myocardial infarction; and early diagnosis and management of acute heart failure, and to evaluate in detail selected alternative biomarkers and recent insights gained from measuring novel biomarkers in large randomized treatment studies in patients with stable coronary artery disease, a setting in which alternative biomarkers may play a more prominent role in the future.

Elevated PAPP-A sets alarm bells ringing in patients with cardiac chest pain

Novel biochemical markers may improve the estimation of overall risk in subjects at a high risk of adverse cardiac events. Measurement of some of these markers, including pregnancy-associated plasma protein A (PAPP-A), brings significant prognostic information independent of traditional risk factors. PAPP-A has been recently identified as a marker of plaque destabilization with growing interest in cardiovascular research. Our group has recently demonstrated that higher levels of serum PAPP-A were independently associated with an increased short-term risk of cardiovascular events in a large sample of 2568 consecutive patients presenting with cardiac chest pain. PAPP-A levels above 34.6 mIU/l in cardiac chest-pain patients sets alarm bells ringing as a warning for higher risk of short-term cardiovascular adverse events, including stent thrombosis, myocardial infarction, ischemic stroke or cardiovascular-related death within 90 days, the combined primary end point of this study. Cardiac chest pain patients with PAPP-A levels above 34.6 mIU/l may suffer from adverse cardiovascular events five times more frequently within 90 days than those with lower PAPP-A levels (hazard ratio: 5.28; 95% CI: 3.81-7.31). However, current data do not support the diagnostic role of PAPP-A for acute coronary syndrome in comparison to the gold standard biomarker troponin. Additionally, PAPP-A is known to interact with heparin, which may diminish its potential utility in every day clinical life. Future multicenter and large-volume studies are warranted to validate the use of PAPP-A in routine clinical practice.

Pregnancy-associated plasma protein A predicts adverse vascular events in patients with coronary heart disease: a systematic review and meta-analysis

INTRODUCTION

Prospective studies about the association between elevated circulating pregnancy-associated plasma protein A (PAPP-A) and adverse vascular events in patients with coronary heart diseases (CHD) are inconsistent. We performed a meta-analysis to clarify this issue.

MATERIAL AND METHODS

We identified prospective studies by searching MEDLINE. The vascular outcomes included all-cause mortality, combination of all-cause mortality and non-fatal myocardial infarction (MI), and combined cardiovascular events. Prospective studies providing multivariable adjusted relative risks (RRs) and their 95% confidence intervals (CIs) of pre-mentioned outcomes were included. A random-effects model was used to calculate the pooled RRs. Subgroup and sensitivity analyses were used to explore the potential sources of heterogeneity or modifiable factors.

RESULTS

Fourteen studies with a total of 12 830 participants were included. Elevated PAPP-A level was associated with all-cause mortality (pooled RR 1.74, 95% CI: 1.45 to 2.09, p < 0.001), combined all-cause mortality and non-fatal MI (RR 1.59, 95% CI: 1.37 to 1.85, p < 0.001) and combined cardiovascular events (RR 1.50, 95% CI: 1.22 to 1.85, p < 0.001). There was no significant heterogeneity. Subgroup and sensitivity analyses showed that the positive association was not affected by follow-up term, CHD type, different assay methods of PAPP-A, or studies with less than 5 adjusted variables.

CONCLUSIONS

Elevated serum PAPP-A level is associated with adverse vascular outcomes in patients with CHD.

Plaque characteristics and serum pregnancy-associated plasma protein A levels predict the no-reflow phenomenon after percutaneous coronary intervention

OBJECTIVES

To investigate the relationship between serum plasma pregnancy-associated plasma protein A (PAPP-A) and coronary plaque characteristics, and their prognostic value for coronary no-reflow after percutaneous coronary intervention (PCI).

METHODS

Patients with unstable angina undergoing PCI were divided into a normal reflow group and a no-reflow group after stent deployment. Coronary blood flow was measured angiographically; plaque components were detected by virtual histology intravascular ultrasound. Serum PAPP-A and high-sensitivity C-reactive protein (hsCRP) were measured before PCI. Cardiac troponin T (cTnT) was measured before and 24 h after PCI.

RESULTS

A total of 166 patients with unstable angina undergoing PCI were included: normal reflow group (n = 145) and no-reflow group (n = 21), after stent deployment. Baseline coronary blood flow was similar in the two groups. The no-reflow group had plaques with less-fibrotic tissue and a larger necrotic core, more thin-cap fibroatheromas and plaque ruptures, and higher serum PAPP-A, hsCRP and post-PCI cTnT levels than the normal reflow group. Serum PAPP-A was correlated negatively with plaque fibrotic area and positively with necrotic core area.

CONCLUSION

High serum PAPP-A and plaque lesions with a large necrotic core are associated with the no-reflow phenomenon after PCI, in patients with unstable angina.

PAPP-A in cardiac and non-cardiac conditions

Pregnancy-associated plasma protein-A (PAPP-A), a newly discovered member of insulin like growth factors (IGFs) axis, has been reported to be a biomarker in both cardiac and non-cardiac conditions. PAPP-A mainly acts as a protease cleaving IGF inhibitors - IGF binding proteins (IGFBPs), thereby setting free IGFs. In cardiac conditions, PAPP-A plays an important role in progressive atherosclerosis. As a biomarker, PAPP-A is not only sensitive, specific and early for diagnosis of acute coronary syndrome, but also an independent risk factor for all-cause mortality or combined cardiovascular events. In non-cardiac conditions, PAPP-A is a new anti-aging target. PAPP-A knock out (KO) mice have a prolonged lifespan than the wild type. In addition, PAPP-A is also a biomarker associated with malignant cancer and end stage renal disease.

Ischaemic heart disease in pregnancy

Ischaemic heart disease (IHD) in pregnancy, particularly myocardial infarction (MI), is a rare yet potentially fatal condition for the mother and the foetus. With delays in the age of conception, the changes in some social habits among females including cigarette and shisha smoking in addition to an increased prevalence of diabetes mellitus, IHD may represent a real hazard among pregnant women in the near future. The difficulty in the diagnosis emerges from the similarity of the signs and symptoms of ischaemia and infarct to some of the physiological adaptations that occur in a normal pregnancy. The physiological changes that are normal in pregnancy may aggravate pre-existing disease and may unmask some underlying unrecognized coronary vascular changes; therefore, the diagnosis requires a high index of suspicion and careful assessment of the underlying risk factors. The management of IHD always requires a multidisciplinary team approach. The management of each patient should be individualized according to the clinical condition, the risk factors, and the availability of the necessary support. Pregnancy after MI may be an acceptable and reasonably safe option provided the cited criteria are met. A systematic PubMed search was performed to identify all published data including cases reports, small series and systematic reviews in the existing literature. These publications were comprised of both retrospective and cross sectional population studies to maximize the number of cases considered in order to reach conclusions and make recommendations based on the best available evidence considering the rare occurrence of this event. The epidemiology, diagnosis, medical and surgical treatment, and prognosis of IHD in pregnancy are the subjects of the present review.

Markers of plaque instability in the early diagnosis and risk stratification of acute myocardial infarction

BACKGROUND

Plaque erosion and plaque rupture occur early in the pathophysiology of acute myocardial infarction (AMI). We hypothesized that markers of plaque instability might be useful in the early diagnosis and risk stratification of AMI.

METHODS

In this multicenter study, we examined 4 markers of plaque instability, myeloperoxidase (MPO), myeloid-related protein 8/14 (MRP-8/14), pregnancy-associated plasma protein-A (PAPP-A), and C-reactive protein (CRP) in 398 consecutive patients presenting to the emergency department with acute chest pain and compared them to normal and high-sensitivity cardiac troponin T (cTnT and hs-cTnT). The final diagnosis was adjudicated by 2 independent cardiologists. Primary prognostic end point was death during a median follow-up of 27 months.

RESULTS

The adjudicated final diagnosis was AMI in 76 patients (19%). At emergency department presentation, concentrations of all 4 biomarkers of plaque instability were significantly higher in patients with AMI than in patients with other diagnoses. However, their diagnostic accuracy as quantified by the area under the ROC curve (AUC) was low (MPO 0.63, MRP-8/14 0.65, PAPP-A 0.62, CRP 0.59) and inferior to both normal and high-sensitivity cardiac troponin T (cTnT 0.88, hs-cTnT 0.96; P<0.001 for all comparisons). Thirty-nine patients (10%) died during follow-up. Concentrations of MPO, MRP-8/14, and CRP were higher in nonsurvivors than in survivors and predicted all-cause mortality with moderate accuracy.

CONCLUSIONS

Biomarkers of plaque instability do not seem helpful in the early diagnosis of AMI but may provide some incremental value in the risk stratification of patients with acute chest pain.

Pregnancy-associated plasma protein A in obese children: relationship to markers and risk factors of atherosclerosis and members of the IGF system

BACKGROUND

Pregnancy-associated plasma protein A (PAPPA) is a large placenta-derived glycoprotein, which serves as a protease of several IGF-binding proteins (IGFBPs). In non-pregnant adults, measurable PAPPA levels were detected and have been implicated in the pathophysiology of atherosclerotic plaques. However, data in children is lacking.

OBJECTIVE

To study the relationship between PAPPA, markers of atherosclerosis, and members of the IGF system in pediatric obesity.

PATIENTS AND DESIGN

Eighty-two obese and 52 nonobese children and 1-year longitudinal follow-up study for obese cohort.

INTERVENTION

Outpatient 1-year intervention program based on exercise, behavior, and nutrition therapy.

MAIN OUTCOME MEASURES

Changes in PAPPA levels, carotid intima media thickness (IMT), weight, blood pressure, lipids, metabolic markers, and members of IGF system.

RESULTS

Baseline PAPPA (PAPPA(BL)) serum levels did not differ between obese and lean subjects. PAPPA(BL) correlated significantly with IGF1, IGFBP1, and serum cholesterol. During the 1-year-program mean IMT decreased from 0.66 ± 0.01 to 0.63 ± 0.01 mm (P<0.05) and PAPPA from 1.83 ± 0.12 to 1.58 ± 0.11 μU/l (P<0.00). In linear regression analysis with IMT after intervention as dependent variable, PAPPA contributed significantly to the observed variance. The longitudinal change of PAPPA correlated significantly with the change of serum triglycerides.

CONCLUSION

In this cohort of obese children, PAPPA serum levels correlated significantly with other cardiovascular risk factors. The lack of a direct correlation between PAPPA and IMT suggests that the described association of atherosclerotic plaques and increased PAPPA levels might reflect an indirect mechanism of PAPPA with cardiovascular risk factors such as serum lipids rather than a direct effect on the vasculature.

Established and novel biomarkers in ST-elevation myocardial infarction

Cardiac biomarkers assist in the diagnosis of and risk stratification in acute coronary syndromes. In ST-elevation myocardial infarction (STEMI), rapid diagnosis and initiation of reperfusion via primary percutaneous coronary intervention or fibrinolysis is often based on the clinical history and presenting ECG, but measurement of biomarkers in the early and/or late phases of STEMI may allow the selection of patients who are at increased or decreased risk of subsequent complications. Although the measurement of only three biomarkers (troponin, natriuretic peptides and C-reactive protein) are currently included in practice guidelines, more than 20 other novel cardiac biomarkers have been proposed to provide improved risk stratification after a STEMI.

Positive correlation between pregnancy-associated plasma protein-A level and OX40 ligand expression in patients with acute coronary syndromes

OBJECTIVE

Increasing evidence show that serum pregnancy-associated plasma protein-A (PAPP-A) and OX40 ligand (OX40L) expression have been implicated in acute coronary syndromes (ACS). We investigated the relationship between PAPP-A level and OX40L in serum and membrane-bound OX40L in patients with ACS.

METHODS

The present study included normal controls (n=30), patients with stable angina (SA) (n=60) and patients with ACS, including unstable angina (UA) (n=50) and acute myocardial infarction (AMI) (n=30). Serum concentrations of PAPP-A and soluble OX40L (sOX40L) were determined with Elisa, whereas the expression of OX40L on monocytes were analyzed with flow cytometry.

RESULTS

The expression of OX40L in peripheral monocytes in patients with UA [25.6±5.5 mean fluorescence intensity (MFI)] and AMI (29.4±6.3MFI) were significantly higher than those in patients with SA (10.6±2.8MFI) and controls (11.1±3.5MFI). Both sOX40L and PAPP-A in patients with UA (15.7±4.9ng/mL, 25.4±6.8μg/mL, respectively) and AMI (17.1±5.3ng/mL, 26.3±5.6μg/mL, respectively) were significantly higher than those in patients with SA (3.4±1.4ng/mL, 9.6±2.1μg/mL, respectively) and controls (3.9±1.3ng/mL, 8.5±2.8μg/mL, respectively) (P<0.001). Interestingly, a positive correlation was found between sOX40L, membrane-bound OX40L and serum PAPP-A levels (r(1)=0.54, r(2)=0.51; P<0.0001). Both serum and membrane-bound OX40L and PAPP-A levels significantly correlated with complex coronary stenosis (r(1)=0.56, r(2)=0.55, r(3)=0.40; P<0.001).

CONCLUSION

PAPP-A level was significantly related to soluble and membrane-bound OX40L in patients with ACS. Enhanced level of serum PAPP-A and sOX40L might represent a prognostic marker for coronary disease activity.