Pregnancy-associated plasma protein-A promotes TF procoagulant activity in human endothelial cells by Akt-NF-κB axis

The Pregnancy-Associated Plasma Protein-A (PAPP-A) Story

Pregnancy-associated plasma protein-A (PAPP-A) was first identified in the early 1970s as a placental protein of unknown function, present at high concentrations in the circulation of pregnant women. In the mid-to-late 1990s, PAPP-A was discovered to be a metzincin metalloproteinase, expressed by many nonplacental cells, that regulates local insulin-like growth factor (IGF) activity through cleavage of high-affinity IGF binding proteins (IGFBPs), in particular IGFBP-4. With PAPP-A as a cell surface-associated enzyme, the reduced affinity of the cleavage fragments results in increased IGF available to bind and activate IGF receptors in the pericellular environment. This proteolytic regulation of IGF activity is important, since the IGFs promote proliferation, differentiation, migration, and survival in various normal and cancer cells. Thus, there has been a steady growth in investigation of PAPP-A structure and function outside of pregnancy. This review provides historical perspective on the discovery of PAPP-A and its structure and cellular function, highlights key studies of the first 50 years in PAPP-A research, and introduces new findings from recent years.

Integrating Mechanisms in Thrombotic Peripheral Arterial Disease

Peripheral arterial disease (PAD), a manifestation of systemic atherosclerosis, is underdiagnosed in the general population. Despite the extensive research performed to unravel its pathophysiology, inadequate knowledge exists, thus preventing the development of new treatments. This review aims to highlight the essential elements of atherosclerosis contributing to the pathophysiology of PAD. Furthermore, emphasis will be placed on the role of thrombo-inflammation, with particular focus on platelet and coagulation activation as well as cell-cell interactions. Additional insight will be then discussed to reveal the contribution of hypercoagulability to the development of vascular diseases such as PAD. Lastly, the current antithrombotic treatments will be discussed, and light will be shed on promising new targets aiming to aid the development of new treatments.

Vulnerable Atherosclerotic Plaque: Is There a Molecular Signature?

Atherosclerosis and its clinical manifestations, coronary and cerebral artery diseases, are the most common cause of death worldwide. The main pathophysiological mechanism for these complications is the rupture of vulnerable atherosclerotic plaques and subsequent thrombosis. Pathological studies of the vulnerable lesions showed that more frequently, plaques rich in lipids and with a high level of inflammation, responsible for mild or moderate stenosis, are more prone to rupture, leading to acute events. Identifying the vulnerable plaques helps to stratify patients at risk of developing acute vascular events. Traditional imaging methods based on plaque appearance and size are not reliable in prediction the risk of rupture. Intravascular imaging is a novel technique able to identify vulnerable lesions, but it is invasive and an operator-dependent technique. This review aims to summarize the current data from literature regarding the main biomarkers involved in the attempt to diagnose vulnerable atherosclerotic lesions. These biomarkers could be the base for risk stratification and development of the new therapeutic drugs in the treatment of patients with vulnerable atherosclerotic plaques.

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.

LncRNA XIST regulates atherosclerosis progression in ox-LDL-induced HUVECs

Long noncoding RNAs (lncRNAs) have been verified as vital regulators in human disease, including atherosclerosis. However, the precise role of X-inactive-specific transcript (XIST) in atherosclerosis remains unclear. The proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs) exposed to low-density lipoprotein (ox-LDL) were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide, and flow cytometry assays, correspondingly. The western blot assay was used to quantify protein expression. Lactate dehydrogenase activity and the concentrations of inflammatory factors were measured by matched kits. The real-time quantitative polymerase chain reaction (qPCR) was used to determine α-smooth muscle actin, smooth muscle protein 22-α, XIST, miR-98-5p, and pregnancy-associated plasma protein A (PAPPA) levels in HUVECs. The relationship among XIST, miR-98-5p, and PAPPA was analyzed by dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. We found ox-LDL repressed proliferation and induced inflammation and apoptosis in HUVECs. Loss-of-functional experiment suggested that the downregulation of XIST overturned the ox-LDL-induced effects on HUVECs. Additionally, overexpression of miR-98-5p-induced effects on ox-LDL-stimulated HUVECs was abolished by upregulation of XIST. However, silencing of miR-98-5p strengthened the ox-LDL-induced effects on HUVECs by increasing expression of PAPPA. Mechanistically, XIST could regulate PAPPA expression in ox-LDL-induced HUVECs by sponging miR-98-5p, providing understanding for atherosclerosis.

Pregnancy-Associated Plasma Protein A Induces Inflammatory Cytokine Expression by Activating IGF-I/PI3K/Akt Pathways

Pregnancy-associated plasma protein A (PAPP-A) was previously reported to be an inflammatory biomarker and a prognostic marker of acute coronary syndrome (ACS) and involved in the process of atherosclerosis and plaque rupture. However, the role of PAPP-A in inflammation is poorly understood. In this study, we aimed to investigate the role of PAPP-A in macrophage activation and inflammatory cytokine production. RAW264.7 macrophages were treated with or without PAPP-A. Reverse-transcriptase quantitative real-time PCR (RT-qPCR) and Western blot were performed to detect gene and protein expressions. The concentration of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in culture supernatants was determined by ELISA. Results showed that PAPP-A significantly stimulated the expression of MCP-1, TNF-α, and IL-6 at both transcriptional and translational levels in a dose-dependent and time-dependent manner. The secretion of these inflammatory cytokines by macrophages was also increased after PAPP-A treatment. Moreover, PAPP-A activated the IGF-I/PI3K/Akt signaling pathway in macrophages. The PAPP-A-mediated upregulation of MCP-1, TNF-α, and IL-6 mRNA and protein levels were strongly inhibited by PI3K inhibitors or IGF-IR siRNA, indicating that the upregulation of MCP-1, TNF-α, and IL-6 could involve the IGF-I/PI3K/Akt pathway. Together, this study demonstrates that PAPP-A activates the macrophage signaling pathway (IGF-I/PI3K/Akt), which drives the expression and production of inflammatory cytokines known to contribute to the initiation and progression of ACS. These findings indicate that PAPP-A may play a proinflammatory role in the pathophysiology of ACS and serve as a potential therapeutic target.

Elevated PAPP-A levels in lean patients with polycystic ovary syndrome

OBJECTIVES

This study aimed to evaluate the serum concentrations of PAPP-A (pregnancy associated placental protein-A), a biomarker which is associated with cardiovascular disease, in patients with polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

A total of 62 women with PCOS, and 68 age and body mass index (BMI) matched controls were eligible for the study. Hirsutism scores, hormonal and metabolic profile as well as PAPP-A levels were assessed in each subject.

RESULTS

Women with PCOS and controls yielded similar median serum levels of PAPP-A (1.7 ng/ml versus 1.8 ng/ml, respectively, p = 0.328). However, when patients were compared based on BMI; subgroup analyses found that among women with BMI<27 kg/m², patients with PCOS exhibited higher PAPP-A levels than controls (2.1 ng/ml versus 1.8 ng/ml, respectively, p = 0.018). When women with PCOS were evaluated in their own based on BMI, lean PCOS women showed higher levels of PAPP-A (2.1 ng/ml versus 1.5 ng/ml, p = 0.002). PAPP-A levels were negatively correlated with age (p = 0.031, r = -0.189), BMI (p = 0.002, r = -0.265) and triglyceride levels (p < 0.001, r = -0.3).

CONCLUSION

The data of the present study suggested that PAPP-A might be a clinical indicator in PCOS, in which the risks of metabolic syndrome and cardiovascular event are increased. Especially a group of young patients with BMI <27 kg/m² might benefit from the cardiovascular risk evaluation using PAPP-A, supplying prognostic information for high risk in the development of cardiovascular disease.

The placental bed vascular pathology revisited: a risk indicator for cardiovascular disease

AIM

The present paper intends in the first place to clarify the confusing terminology for describing the vascular pathology of the placental bed in relation to long-term risk of cardiovascular disease.

METHODS

Systematic review of relevant topics.

RESULTS

The maternal blood supply to the placenta is achieved by some 100 utero-placental spiral arteries with an outside diameter varying between 200 and 600 microns. Defective physiological changes of the myometrial segment of utero-placental spiral arteries and, particularly in preeclampsia associated to hypertensive disease, the presence of atherosclerosis in their proximal segment are a cause of obstructive vascular pathology. On the other hand, basal arteries which supply the inner myometrium and basal decidua are not affected by physiological change and maintain their musculoelastic structure. They can be identified by their external diameter of less than 120 microns. Acute atherosis is an aspecific vascular lesion that occurs in basal as well as spiral arteries inside, as well as outside, the placental bed in association with a variety of obstetrical conditions.

CONCLUSIONS

An increased risk of future cardiovascular disease, should be linked to atherosis or, at a later stage, atherosclerosis of utero-placental spiral arteries, rather than to that of decidual basal arteries.

Upregulation of TH/IL-17 Pathway-Related Genes in Human Coronary Endothelial Cells Stimulated with Serum of Patients with Acute Coronary Syndromes

Background

Inflammation plays an essential role in the development and complications of atherosclerosis plaques, including acute coronary syndromes (ACS). Indeed, previous reports have shown that within the coronary circulation of ACS patients, several soluble mediators are released. Moreover, it has been demonstrated that endothelial dysfunction might play an important role in atherosclerosis as well as ACS pathophysiology. However, the mechanisms by which these soluble mediators might affect endothelial functions are still largely unknown. We have evaluated whether soluble mediators contained in serum from coronary circulation of ACS patients might promote changes of gene profile in human coronary endothelial cells (HCAECs).

Methods

HCAECs were stimulated in vitro for 12 h with serum obtained from the coronary sinus (CS) and the aorta (Ao) of ACS patients; stable angina (SA) patients served as controls. Gene expression profiles of stimulated cells were evaluated by microarray and real-time PCR.

Results

HCAECs stimulated with serum from CS of ACS patients showed a significant change (upregulation and downregulation) in gene expression profile as compared with cells stimulated with serum from CS of SA patients. Moreover, ad hoc sub analysis indicated the upregulation of Th-17/IL-17 pathway-related genes.

Conclusion

This study demonstrates that, in ACS patients, the chemical mediators released in the coronary circulation might be able to perturb coronary endothelial cells (ECs) modifying their gene profile. These modified ECs, through downregulation of protective gene and, mainly, through upregulation of gene able to modulate the Th-17/IL-17 pathway, might play a key role in progression of coronary atherosclerosis and in developing future acute events.

Predictive value of serum pregnancy-associated plasma protein A for patients with ischemic cerebrovascular disease

BACKGROUND

To investigate the role of pregnancy-associated plasma protein A (PAPP-A) in the outcome of ischemic cerebrovascular disease.

METHODS

We analyzed the levels of PAPP-A in the transient ischemic attack (TIA) patients, ischemic stroke (IS) patients and normal control, and followed up the outcome of the patients in the following 2 years. Blood samples were drawn at admission, prior to treatment with heparins.

RESULTS

The levels of PAPP-A in TIA patients, IS patients and normal control were 4.91 (2.11, 6.48) mIU/L, 6.77 (3.31, 10.23) mIU/L and 4.25 (1.76, 5.22) mIU/L, respectively. The follow-up results of TIA patients and IS patients indicated the PAPP-A concentration in the poor prognosis group were higher than those in the good prognosis group (5.90 vs 4.46 mIU/L, P<.05, 10.06 vs 5.12 mIU/L, P<.05, respectively). Serum PAPP-A concentration emerged as a predictor of risk stratification with an OR of 1.41 and 1.25 (P<.05, P<.05).

CONCLUSIONS

Higher PAPP-A concentration has a forecasting value on prognosis in ischemic cerebrovascular disease.