Cardiac expression of placental growth factor predicts the improvement of chronic phase left ventricular function in patients with acute myocardial infarction

Fibroblasts activation by embryonic signal switching: A novel mechanism of placental growth factor-induced cardiac remodeling

INTRODUCTION

Cardiac remodeling is defined as cellular interstitial changes that lead dysfunction of the heart after injury. Placental growth factor (PlGF), a member of the VEGF family, has been reported to regulate cardiac hypertrophy in hemodynamic state. We therefore analyze the function of PlGF during cardiac remodeling using cardiac cells and fibroblasts, under Angiotensin II (AngII) stimulation.

METHODS

PlGF overexpressed mouse embryonic fibroblasts derived from C57BL/6 mice, were made by deficient retrovirus vector, designated as C57/PlGF. Only retrovirus vector introduced C57 cells (C57/EV) were used as control. After AngII stimulation, wound scratching assay and MTT proliferation assay with or without p38 MAPK inhibitor, SB205580 were performed in retrovirally-introduced C57 cells. Reactive oxygen species (ROS) production, NF-kB activation, IL-6 and TNF-α production were also measured. Then we assessed AngII-induced cell proliferation of mouse cardiac fibroblasts (CFs) and rat primary cardiomyocytes incubating with C57/PlGF conditioned-medium.

RESULTS

The PlGF production in C57/PlGF were confirmed by ELISA (1093.48 ± 3.5 pg/ml, ±SE). AngII-induced cell migration, proliferation and H2O2 production were increased in C57/PlGF compared with C57/EV. SB205580 inhibited the AngII-induced cell proliferation in C57/PlGF. In C57/PlGF cells, NF-kB activation was higher, followed by up-regulation of IL-6 and TNF-α production. CFs and cardiomyocytes proliferation increased when stimulated with C57/PlGF conditioned-medium.

DISCUSSION

The activation of fibroblast is stimulated by PlGF signaling via p38 MAPK/NF-kB pathway accompanied by elevation of ROS and inflammatory response. Furthermore, these signals stimulate the activation of CFs and cardiomyocytes, indicating that high circulating level of PlGF have a potential to regulate cardiac remodeling.

​Comprehensive mendelian randomization analysis of plasma proteomics to identify new therapeutic targets for the treatment of coronary heart disease and myocardial infarction

BACKGROUND

Ischemic heart disease is one of the leading causes of mortality worldwide, and thus calls for development of more effective therapeutic strategies. This study aimed to identify potential therapeutic targets for coronary heart disease (CHD) and myocardial infarction (MI) by investigating the causal relationship between plasma proteins and these conditions.

METHODS

A two-sample Mendelian randomization (MR) study was performed to evaluate more than 1600 plasma proteins for their causal associations with CHD and MI. The MR findings were further confirmed through Bayesian colocalization, Summary-data-based Mendelian Randomization (SMR), and Transcriptome-Wide Association Studies (TWAS) analyses. Further analyses, including enrichment analysis, single-cell analysis, MR analysis of cardiovascular risk factors, phenome-wide Mendelian Randomization (Phe-MR), and protein-protein interaction (PPI) network construction were conducted to verify the roles of selected causal proteins.

RESULTS

Thirteen proteins were causally associated with CHD, seven of which were also causal for MI. Among them, FES and PCSK9 were causal proteins for both diseases as determined by several analytical methods. PCSK9 was a risk factor of CHD (OR = 1.25, 95% CI: 1.13-1.38, P = 7.47E-06) and MI (OR = 1.36, 95% CI: 1.21-1.54, P = 2.30E-07), whereas FES was protective against CHD (OR = 0.68, 95% CI: 0.59-0.79, P = 6.40E-07) and MI (OR = 0.65, 95% CI: 0.54-0.77, P = 5.38E-07). Further validation through enrichment and single-cell analysis confirmed the causal effects of these proteins. Moreover, MR analysis of cardiovascular risk factors, Phe-MR, and PPI network provided insights into the potential drug development based on the proteins.

CONCLUSIONS

This study investigated the causal pathways associated with CHD and MI, highlighting the protective and risk roles of FES and PCSK9, respectively. FES. Specifically, the results showed that these proteins are promising therapeutic targets for future drug development.

Causal association between placental growth factor and coronary heart disease: a Mendelian randomization study

OBJECTIVE

Placental growth factor (PlGF), an important polypeptide hormone, plays an important regulatory role in various physiological processes. Observational studies have shown that PlGF is associated with the risk of coronary heart disease (CHD). However, the causal association between PlGF and CHD is unclear at present. This study aimed to investigate the causal association between genetically predicted PlGF levels and CHD.

METHODS

Single nucleotide polymorphisms (SNPs) associated with PlGF were selected as instrumental variables (IVs) to evaluate the causal association between genetically predicted circulating PlGF levels and CHD risk by two-sample Mendelian randomization (MR).

RESULTS

Inverse variance weighted (IVW) analysis showed that there was a suggestive causal association between genetically predicted PlGF level and the risk of CHD (OR = 0.79, 95% CI: 0.66-0.95, P = 0.011) overall. In addition, PlGF levels had a significant negative causal association with the risk of myocardial infarction (OR = 0.83, 95% CI: 0.72-0.95, P = 0.007). A negative correlation trend was found between PlGF level and the risk of angina pectoris (OR = 0.89, 95% CI: 0.79-1.01, P = 0.067). In addition, PlGF levels had a significant negative association with the risk of unstable angina pectoris (OR = 0.78, 95% CI: 0.64-0.94, P = 0.008). PlGF levels were negatively correlated with CHD events with suggestive significance (OR = 0.89, 95% CI: 0.80-0.99, P = 0.046).

CONCLUSION

Genetically predicted circulating PlGF levels are causally associated with the risk of CHD, especially acute coronary syndrome, and PlGF is a potential therapeutic target for CHD.

Literature Review: The sFlt1/PlGF Ratio and Pregestational Maternal Comorbidities: New Risk Factors to Predict Pre-Eclampsia

One of the main causes of maternal and neonatal morbidity and mortality is pre-eclampsia. It is characterized by a high sFlt1/PlGF ratio, according to prior research. Pregestational diseases in mothers may increase the risk of developing pre-eclampsia. Only a few studies have looked at the connection between maternal comorbidities before conception and the sFlt1/PlGF ratio. The most recent information regarding the association between maternal pregestational diseases and the ratio of sFlt1/PlGF is described in this review. The paper also examines current research suggesting that changes in pregnancy hormones and metabolites are related to a high sFlt1/PlGF ratio. Certain maternal disorders have been found to dramatically raise sFlt-1 and sFlt1/PlGF levels, according to an analysis of the literature. There is still debate about the data on the association between the sFlt1/PlGF ratio and maternal disorders such as HIV, acute coronary syndromes, cardiovascular function in the mother between 19 and 23 weeks of pregnancy, thyroid hormones, diabetes, and cancer. Additional research is needed to confirm these findings.

The Role of Inflammation in The Cellular and Molecular Mechanisms of Cardiopulmonary Complications of Sickle Cell Disease

Cardiopulmonary complications remain the major cause of mortality despite newer therapies and improvements in the lifespan of patients with sickle cell disease (SCD). Inflammation has been identified as a major risk modifier in the pathogenesis of SCD-associated cardiopulmonary complications in recent mechanistic and observational studies. In this review, we discuss recent cellular and molecular mechanisms of cardiopulmonary complications in SCD and summarize the most recent evidence from clinical and laboratory studies. We emphasize the role of inflammation in the onset and progression of these complications to better understand the underlying pathobiological processes. We also discuss future basic and translational research in addressing questions about the complex role of inflammation in the development of SCD cardiopulmonary complications, which may lead to promising therapies and reduce morbidity and mortality in this vulnerable population.

Progress on the role of traditional Chinese medicine in therapeutic angiogenesis of heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

Cardiovascular diseases are still the leading cause of death worldwide. Heart failure (HF), as the terminal stage of many cardiovascular diseases, has brought a heavy burden to the global medical system. Microvascular rarefaction (decreased myocardial capillary density) with reduced coronary flow reserve is a hallmark of HF and therapeutic myocardial angiogenesis is now emerging as a promising approach for the prevention and treatment in HF. Traditional Chinese medicine (TCM) has made remarkable achievements in the treatment of many cardiovascular diseases. Growing evidence have shown that their protective effect in HF is closely related to therapeutic angiogenesis.

AIM OF THE STUDY

This review is to enlighten the therapeutic effect and pro-angiogenic mechanism of TCM in HF, and provide valuable hints for the development of pro-angiogenic drugs for the treatment of HF.

MATERIALS AND METHODS

The relevant information about cardioprotective TCM was collected from electronic scientific databases such as PubMed, Web of Science, ScienceDirect, and China National Knowledge Infrastructure (CNKI).

RESULTS

The studies showed that TCM formulas, extracts, and compounds from herbal medicines can provide therapeutic effect in HF with their pro-angiogenic activity. Their actions are achieved mainly by regulating the key angiogenesis factors particularly VEGF, as well as related regulators including signal molecules and pathways, non-coding miRNAs and stem cells.

CONCLUSION

TCM and their active components might be promising in therapeutic angiogenesis for the treatment of HF.

Cord blood cardiovascular biomarkers in tetralogy of fallot and D-transposition of great arteries

Previous reports suggest that cord blood biomarkers could serve as a prognostic tool for conotruncal congenital heart defects (CHD). We aimed to describe the cord blood profile of different cardiovascular biomarkers in a prospective series of fetuses with tetralogy of Fallot (ToF) and D-transposition of great arteries (D-TGA) and to explore their correlation with fetal echocardiography and perinatal outcome.

Methods

A prospective cohort study (2014-2019), including fetuses with isolated ToF and D-TGA and healthy controls, was conducted at two tertiary referral centers for CHD in Barcelona. Obstetric ultrasound and fetal echocardiography were performed in the third trimester and cord blood was obtained at delivery. Cord blood concentrations of N-terminal precursor of B-type natriuretic peptide, Troponin I, transforming growth factorβ (TGFβ), placental growth factor, and soluble fms-like tyrosine kinase-1 were determined.

Results

Thirty-four fetuses with conotruncal-CHD (22 ToF and 12 D-TGA) and 36 controls were included. ToF-fetuses showed markedly increased cord blood TGFβ (24.9 ng/ml (15.6-45.3) vs. normal heart 15.7 ng/ml (7.2-24.3) vs. D-TGA 12.6 ng/ml (8.7-37.9); P = 0.012). These results remained statistically significant even after adjusting for maternal body mass index, birth weight and mode of delivery. TGFß levels showed a negative correlation with the pulmonary valve diameter z-score at fetal echocardiography (r = -0.576, P = 0.039). No other differences were found in the rest of cord blood biomarkers among the study populations. Likewise, no other significant correlations were identified between cardiovascular biomarkers, fetal echocardiography and perinatal outcome.

Conclusions

This study newly describes increased cord blood TGFβ concentrations in ToF compared to D-TGA and normal fetuses. We also demonstrate that TGFβ levels correlate with the severity of right ventricle outflow obstruction. These novel findings open a window of research opportunities on new prognostic and potential preventive strategies.

Cord Blood Cardiovascular Biomarkers in Left-Sided Congenital Heart Disease

Fetal echocardiography has limited prognostic ability in the evaluation of left-sided congenital heart defects (left heart defects). Cord blood cardiovascular biomarkers could improve the prognostic evaluation of left heart defects. A multicenter prospective cohort (2013−2019) including fetuses with left heart defects (aortic coarctation, aortic stenosis, hypoplastic left heart, and multilevel obstruction (complex left heart defects) subdivided according to their outcome (favorable vs. poor), and control fetuses were evaluated in the third trimester of pregnancy at three referral centers in Spain. Poor outcome was defined as univentricular palliation, heart transplant, or death. Cord blood concentrations of N-terminal precursor of B-type natriuretic peptide, Troponin I, transforming growth factor β, placental growth factor, and soluble fms-like tyrosine kinase-1 were determined. A total of 45 fetuses with left heart defects (29 favorable and 16 poor outcomes) and 35 normal fetuses were included, with a median follow-up of 3.1 years (interquartile range 1.4−3.9). Left heart defects with favorable outcome showed markedly increased cord blood transforming growth factor β (normal heart median 15.5 ng/mL (6.8−21.4) vs. favorable outcome 51.7 ng/mL (13.8−73.9) vs. poor outcome 25.1 ng/mL (6.9−39.0), p = 0.001) and decreased placental growth factor concentrations (normal heart 17.9 pg/mL (13.8−23.9) vs. favorable outcome 12.8 pg/mL (11.7−13.6) vs. poor outcome 11.0 pg/mL (8.8−15.4), p < 0.001). Poor outcome left heart defects had higher N-terminal precursor of B-type natriuretic peptide (normal heart 508.0 pg/mL (287.5−776.3) vs. favorable outcome 617.0 pg/mL (389.8−1087.8) vs. poor outcome 1450.0 pg/mL (919.0−1645.0), p = 0.001) and drastically reduced soluble fms-like tyrosine kinase-1 concentrations (normal heart 1929.7 pg/mL (1364.3−2715.8) vs. favorable outcome (1848.3 pg/mL (646.9−2313.6) vs. poor outcome 259.0 pg/mL (182.0−606.0), p < 0.001). Results showed that fetuses with left heart defects present a distinct cord blood biomarker profile according to their outcome.

sFlt-1 in Chronic Kidney Disease: Friend or Foe?

Placental growth factor (PlGF) and its receptor, fms-like tyrosine kinase-1 (Flt-1), are important regulators involved in angiogenesis, atherogenesis, and inflammation. This review article focuses on the function of PlGF/Flt-1 signaling and its regulation by soluble Flt-1 (sFlt-1) in chronic kidney disease (CKD). Elevation of circulating sFlt-1 and downregulation of sFlt-1 in the vascular endothelium by uremic toxins and oxidative stress both exacerbate heart failure and atherosclerosis. Circulating sFlt-1 is inconsistent with sFlt-1 synthesis, because levels of matrix-bound sFlt-1 are much higher than those of circulating sFlt-1, as verified by a heparin loading test, and are drastically reduced in CKD.

Fluid shear stress regulates placental growth factor expression via heme oxygenase 1 and iron

Increased fluid shear stress (FSS) is a key initiating stimulus for arteriogenesis, the outward remodeling of collateral arterioles in response to upstream occlusion. Placental growth factor (PLGF) is an important arteriogenic mediator. We previously showed that elevated FSS increases PLGF in a reactive oxygen species (ROS)-dependent fashion both in vitro and ex vivo. Heme oxygenase 1 (HO-1) is a cytoprotective enzyme that is upregulated by stress and has arteriogenic effects. In the current study, we used isolated murine mesentery arterioles and co-cultures of human coronary artery endothelial cells (EC) and smooth muscle cells (SMC) to test the hypothesis that HO-1 mediates the effects of FSS on PLGF. HO-1 mRNA was increased by conditions of increased flow and shear stress in both co-cultures and vessels. Both inhibition of HO-1 with zinc protoporphyrin and HO-1 knockdown abolished the effect of FSS on PLGF. Conversely, induction of HO-1 activity increased PLGF. To determine which HO-1 product upregulates PLGF, co-cultures were treated with a CO donor (CORM-A1), biliverdin, ferric ammonium citrate (FAC), or iron-nitrilotriacetic acid (iron-NTA). Of these FAC and iron-NTA induced an increase PLGF expression. This study demonstrates that FSS acts through iron to induce pro-arteriogenic PLGF, suggesting iron supplementation as a novel potential treatment for revascularization.

Involvement of chronic inflammation via monocyte chemoattractant protein-1 in uraemic cardiomyopathy: a human biopsy study

Aims

Patients undergoing dialysis, even those without coronary artery disease or valvular abnormalities, sometimes present with reduced heart function, which resembles dilated cardiomyopathy (DCM). This condition is known as uraemic cardiomyopathy (UCM). The mechanisms of UCM development are not fully understood. Previous studies demonstrated that the balance between placental growth factor (PlGF) and fms‐like tyrosine kinase‐1 (Flt‐1) is correlated with renal function, and PlGF/Flt‐1 signalling is involved in the development of cardiovascular diseases in patients with chronic kidney disease. This study was conducted to evaluate the pathogenesis of UCM and clarify the differences in the mechanisms of UCM and DCM by using human endomyocardial biopsy and blood samples.

Methods and results

The clinical and pathological features of 30 patients on dialysis with reduced cardiac function [left ventricular ejection fraction (LVEF) ≤50%] (UCM group; mean age: 58.5 ± 9.4 years and LVEF: 39.1 ± 7.2%), 196 DCM patients (DCM group; mean age: 62.7 ± 14.0 years and LVEF: 33.5 ± 8.8%) as controls with reduced cardiac function (LVEF ≤ 45%), and 21 patients as controls with normal cardiac function (control group; mean age: 56.2 ± 19.3 years and LVEF: 67.5 ± 6.7%) were analysed. The percentage of the interstitial fibrosis area in the UCM group was greater than that in the DCM group (P = 0.045). In UCM patients, the percentage of the interstitial fibrosis area was positively correlated with the duration of renal replacement therapy (P < 0.001). The number of infiltrated CD68‐positive macrophages in the myocardium and expression of monocyte chemoattractant protein‐1 (MCP‐1) in cardiomyocytes were significantly greater in the UCM group than in the other groups (P < 0.001, respectively). Furthermore, while the serum level of soluble form of Flt‐1, an endogenous inhibitor of PlGF, in the UCM group was lower compared with that in the DCM group (P < 0.001), the serum levels of PlGF and PlGF/soluble form of Flt‐1 ratio and plasma level of MCP‐1 in the UCM group were higher than those in the DCM group (P < 0.001, respectively).

Conclusions

These results suggest that activated PlGF/Flt‐1 signalling and subsequent macrophage‐mediated chronic non‐infectious inflammation via MCP‐1 in the myocardium are involved in the pathogenesis of UCM.

Angiogenic Factors and Long-Term Cardiovascular Risk in Women That Developed Preeclampsia During Pregnancy

Preeclampsia is caused by placental impairment with increased expression of sFlt-1 (soluble fms-like tyrosine kinase 1) and decreased PlGF (placental growth factor); it has been associated with cardiovascular morbidity and mortality later in life, but the underlying mechanism remains unknown. The aim of this study was to determine whether sFlt-1 and PlGF levels during preeclampsia are associated to long-term cardiovascular risk. We prospectively recruited 43 women with previous preeclampsia and 21 controls with uncomplicated pregnancies. Cardiovascular risk assessment ≈12 years later included maternal hemodynamic, cardiac function and structure, biomarker analysis, and carotid-intima thickness evaluation. Women with previous preeclampsia had higher prevalence of hypertensive disorders and dyslipidemia than controls. In addition, they had worse global longitudinal strain, thicker left ventricular septal and posterior walls, more myocardial mass and increased carotid intima-media thickness compared with controls. PlGF during pregnancy correlated positively with high-density lipoprotein (r=0.341; P=0.006), and negatively with global longitudinal strain (r=-0.581; P<0.001), carotid intima-media thickness (r=-0.251; P=0.045), and mean arterial blood pressure (r=-0.252; P=0.045), when adjusted by study group. sFlt correlated negatively with high-density lipoprotein (r=-0.372; P=0.002) and apolipoprotein A-1 (r=-0.257; P=0.040), and positively with carotid intima-media thickness (r=0.269; P=0.032) and left ventricular posterior wall thickness (r=0.368; P=0.003). The antiangiogenic state present in preeclampsia is related to greater prevalence of cardiovascular risk factors ≈12 years after delivery. The knowledge of altered angiogenic factors may help detect women with a higher risk for premature cardiovascular disease, who will require earlier follow-up after delivery.

The Regulatory Role of Histone Modification on Gene Expression in the Early Stage of Myocardial Infarction

Myocardial infarction (MI) is a fatal heart disease with high morbidity and mortality. Various studies have demonstrated that a series of relatively specific biological events occur within 24 h of MI. However, the roles of histone modifications in this pathological process are still poorly understood. To investigate the regulation of histone modifications on gene expression in early MI, we performed RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) on myocardial tissues 24 h after the onset of MI. The genome-wide profiles of five histone marks (H3K27ac, H3K9ac, H3K4me3, H3K9me3, and H3K27me3) were explored through ChIP-seq. RNA-seq identified 1,032 differentially expressed genes (DEGs) between the MI and sham groups. ChIP-seq analysis found that 195 upregulated DEGs were modified by change of at least one of the three active histone marks (H3K27ac, H3K9ac, and H3K4me3), and the biological processes and pathways analysis showed that these DEGs were significantly enriched in cardiomyocyte differentiation and development, inflammation, angiogenesis, and metabolism. In the transcriptional regulatory network, Ets1, Etv1, and Etv2 were predicted to be involved in gene expression regulation. In addition, by integrating super-enhancers (SEs) with RNA-seq data, 76 DEGs were associated with H3K27ac-enriched SEs in the MI group, and the functions of these SE-associated DEGs were mainly related to angiogenesis. Our results suggest that histone modifications may play important roles in the regulation of gene expression in the early stage of MI, and the early angiogenesis response may be initiated by SEs.

Angiogenesis after acute myocardial infarction

Acute myocardial infarction (MI) inflicts massive injury to the coronary microcirculation leading to vascular disintegration and capillary rarefication in the infarct region. Tissue repair after MI involves a robust angiogenic response that commences in the infarct border zone and extends into the necrotic infarct core. Technological advances in several areas have provided novel mechanistic understanding of postinfarction angiogenesis and how it may be targeted to improve heart function after MI. Cell lineage tracing studies indicate that new capillary structures arise by sprouting angiogenesis from pre-existing endothelial cells (ECs) in the infarct border zone with no meaningful contribution from non-EC sources. Single-cell RNA sequencing shows that ECs in infarcted hearts may be grouped into clusters with distinct gene expression signatures, likely reflecting functionally distinct cell populations. EC-specific multicolour lineage tracing reveals that EC subsets clonally expand after MI. Expanding EC clones may arise from tissue-resident ECs with stem cell characteristics that have been identified in multiple organs including the heart. Tissue repair after MI involves interactions among multiple cell types which occur, to a large extent, through secreted proteins and their cognate receptors. While we are only beginning to understand the full complexity of this intercellular communication, macrophage and fibroblast populations have emerged as major drivers of the angiogenic response after MI. Animal data support the view that the endogenous angiogenic response after MI can be boosted to reduce scarring and adverse left ventricular remodelling. The improved mechanistic understanding of infarct angiogenesis therefore creates multiple therapeutic opportunities. During preclinical development, all proangiogenic strategies should be tested in animal models that replicate both cardiovascular risk factor(s) and the pharmacotherapy typically prescribed to patients with acute MI. Considering that the majority of patients nowadays do well after MI, clinical translation will require careful selection of patients in need of proangiogenic therapies.

Flow-Induced Transcriptomic Remodeling of Endothelial Cells Derived From Human Induced Pluripotent Stem Cells

The vascular system is essential for the development and function of all organs and tissues in our body. The molecular signature and phenotype of endothelial cells (EC) are greatly affected by blood flow-induced shear stress, which is a vital component of vascular development and homeostasis. Recent advances in differentiation of ECs from human induced pluripotent stem cells (hiPSC) have enabled development of in vitro experimental models of the vasculature containing cells from healthy individuals or from patients harboring genetic variants or diseases of interest. Here we have used hiPSC-derived ECs and bulk- and single-cell RNA sequencing to study the effect of flow on the transcriptomic landscape of hiPSC-ECs and their heterogeneity. We demonstrate that hiPS-ECs are plastic and they adapt to flow by expressing known flow-induced genes. Single-cell RNA sequencing showed that flow induced a more homogenous and homeostatically more stable EC population compared to static cultures, as genes related to cell polarization, barrier formation and glucose and fatty acid transport were induced. The hiPS-ECs increased both arterial and venous markers when exposed to flow. Interestingly, while in general there was a greater increase in the venous markers, one cluster with more arterial-like hiPS-ECs was detected. Single-cell RNA sequencing revealed that not all hiPS-ECs are similar even after sorting, but exposing them to flow increases their homogeneity. Since hiPS-ECs resemble immature ECs and demonstrate high plasticity in response to flow, they provide an excellent model to study vascular development.

The role of the PlGF/Flt-1 signaling pathway in the cardiorenal connection

Although the concept of the cardiorenal connection is widely accepted, athe underlying molecular mechanism has not been clearly defined. Nevertheless, accumulating evidence indicates that the nervous system and both the humoral and cellular immune systems are all involved. This review article focuses on the roles of the signaling pathway of placental growth factor (PlGF) and its receptor, fms-like tyrosine kinase-1 (Flt-1), in the development of the cardiorenal connection. PlGF, a member of the vascular endothelial cell growth factor family, is a specific ligand for Flt-1 and plays roles in the development of atherosclerosis, wound healing after ischemia injury, and angiogenesis through Flt-1 signaling. Flt-1, a tyrosine-kinase type receptor with a single transmembrane domain, has a soluble isoform (sFlt-1) consisting of only extracellular domains, and is an intrinsic antagonist of PlGF. In renal dysfunction, PlGF is upregulated and sFlt-1 is downregulated by oxidative stress or uremic toxins, leading to activation of the PlGF/Flt-1 signaling pathway, which in turn plays a role in the worsening of atherosclerosis and heart failure, both of which are frequently associated with renal dysfunction. Monocyte chemotactic protein-1 (MCP-1) is involved in the process downstream of the Flt-1 signaling pathway. Plasma levels of sFlt-1 correlate with the severity of renal dysfunction in patients with heart failure or myocardial infarction, and are associated with the incidence of cardiovascular events. This is inconsistent with the concept of relative activation of the PlGF/Flt-1 pathway in renal dysfunction. However, the level of circulating sFlt-1 does not always parallel sFlt-1 synthesis, probably because sFlt-1 is stored on cell surfaces through its heparin-binding domains and its quantity is regulated differently in renal dysfunction. This review summarizes a novel concept wherein noninfectious inflammation via PlGF/Flt-1 signaling is involved in the development of renal dysfunction-related cardiovascular complications.

The placental growth factor attenuates intimal hyperplasia in vein grafts by improving endothelial dysfunction

Saphenous vein grafts (SVG) patency is limited by intimal hyperplasia (IH) caused by endothelial dysfunction. This study aimed to explore the effect of placental growth factor (PlGF) on the endothelial function of SVG. In rat models of external jugular vein-carotid artery graft treated with PlGF or saline hydrogel, PlGF inhibited vein graft IH (day 28: 12.0 ± 1.9 vs. 61.7 ± 13.1 μm, P < 0.001), promoted microvessel proliferation (day 14: 33.3% 3+ vs. 50.0% 2+, P = 0.03), and increased nitric oxide (NO) production (P < 0.05 on days 1/3/5) and NO synthase (NOS) expression by immunohistochemistry. In human umbilical vein endothelial cells (HUVECs) cultured under hypoxia and treated or not with PlGF, PlGF restored the survival (50 ng/ml PlGF, 48 h: 91.7 ± 0.6% vs. 84.9 ± 0.5%, P < 0.01), migration (by Matrigel assay), and tube formation ability (junctions, tubules, and tubule total length; all P < 0.01) of HUVECs after hypoxia. PlGF increased NO production through increased eNOS expression (P < 0.05), without changes in iNOS expression. The mRNA expression of eNOS decreased after the addition of the PI3K inhibitor LY294002 (P < 0.05). PlGF promoted the protein expression of eNOS by up-regulating AKT, and the AKT and eNOS protein levels were decreased after adding LY294002 (all P < 0.05). In conclusion, PlGF is a candidate for the inhibition of IH in SVG after coronary artery bypass graft. The effects of PlGF are mediated by the upregulation of the eNOS mRNA and protein through the PI3K/AKT signaling pathway. PlGF promotes the secretion of NO by endothelial cells and thereby reduces the occurrence and development of IH.

Obstructive sleep apnoea in acute coronary syndrome

Obstructive sleep apnoea (OSA) syndrome affects about 13% of the male and 7-9% of the female population. Hypoxia, oxidative stress and systemic inflammation link OSA and cardiovascular and metabolic consequences, including coronary artery disease. Current research has identified several clinical phenotypes, and the combination of breathing disturbances during sleep, systemic effects and end-organ damage might help to develop personalised therapeutic approaches. It is unclear whether OSA is a risk factor for acute coronary syndrome (ACS) and might affect its outcome. On the one hand, OSA in patients with ACS may worsen prognosis; on the other hand, OSA-related hypoxaemia could favour the development of coronary collaterals, thereby exerting a protective effect. It is unknown whether positive airway pressure treatment may influence adverse events and consequences of ACS. In non-sleepy patients with OSA and stable coronary artery disease, randomised controlled trials failed to show that continuous positive airway pressure (CPAP) treatment protected against cardiovascular events. Conversely, uncontrolled studies suggested positive effects of CPAP treatment in such patients. Fewer data are available in subjects with ACS and OSA, and results of randomised controlled studies on the effects of CPAP are expected shortly. Meanwhile, the search for reliable markers of risk continues. Recent studies suggest that daytime sleepiness may indicate a more severe OSA phenotype with regard to cardiovascular risk. Finally, some studies suggest sex-related differences. The picture is still incomplete, and the potential role of OSA in patients with ACS awaits confirmation, as well as clear definition of subgroups with different degrees of risk.

Placenta growth factor and sFlt-1 as biomarkers in ischemic heart disease and heart failure: a review

Coronary heart disease (CHD) and heart failure (HF) produce significant morbidity/mortality but identifying new biomarkers could help in the management of each. In this article, we summarize the molecular regulation and biomarker potential of PIGF and sFlt-1 in CHD and HF. PlGF is elevated during ischemia and some studies have shown PlGF, sFlt-1 or PlGF:sFlt-1 ratio, when used in combination with standard biomarkers, strengthens predictions of outcomes. sFlt-1 and PlGF are elevated in HF with sFlt-1 as a stronger predictor of outcomes. Although promising, we discuss additional study criteria needed to confirm the clinical usefulness of PlGF or sFlt-1 in the detection and management of CHD or HF.

Mdivi-1 induced acute changes in the angiogenic profile after ischemia-reperfusion injury in female mice

The aim of this study is to determine the effects of mitochondrial division inhibitor 1 (Mdivi‐1), the mitochondrial fission inhibitor, on the angiogenic profiles after the ischemia reperfusion injury (IR injury) in female mice. Female mice were treated with Mdivi‐1 inhibitor, 2 days prior, on the day of IR injury and 2 days after IR injury, for a period of 5 days. Both control and treatment groups underwent 30 min of ischemia and 72 h of reperfusion. On the day 3, mice were sacrificed and the ischemic and nonischemic portions of heart tissue were collected. Relative levels of 53 angiogenesis‐related proteins were quantified simultaneously using Angiogenic arrays. Heart function was evaluated before and after 72 h of IR injury. Mdivi‐1 treatment ameliorated IR induced functional deterioration with positive angiogenic profile. The seminal changes include suppression of Matrix metalloproteinase (MMP3), tissue inhibitor of metalloproteases (TIMP1) and chemokine (C‐X‐C motif) ligand 10 (CXCL10) levels and prevention of connexin 43 (Cx43) loss and downregulation in the antioxidant enzyme levels. These changes are correlated with enhanced endothelial progenitor cell marker (cluster of differentiation (CD31), endothelial‐specific receptor tyrosine kinase (Tek), fMS‐like tyrosine kinase 4 (Flt4) and kinase insert domain protein receptor (Kdr)) presence. Our study is the first to report the role of mitochondrial dynamics in regulation of myocardial IR‐induced angiogenic responses. Inhibition of excessive mitochondrial fission after IR injury ameliorated heart dysfunction and conferred positive angiogenic response. In addition, there were improvements in the preservation of Cx43 levels and oxidative stress handling along with suppression of apoptosis activation. The findings will aid in shaping the rational drug development process for the prevention of ischemic heart disease, especially in females.

Plasma levels of hepatocyte growth factor and placental growth factor predict mortality in a general population: a prospective cohort study

BACKGROUND

Circulating levels of growth factors involved in leucocyte production and angiogenesis could be indicative of underlying aberrations of tissue homeostasis and therefore be utilized as predictors of risk for all-cause cardiovascular disease (CVD) or cancer mortality.

METHODS

Baseline plasma levels of a range of growth factors were measured in two cohorts of the population-based FINRISK study (1997 Discovery cohort, N = 8444, aged 25-74; 2002 Replication cohort, N = 2951, aged 51-74 years) using a multiplexed bead array methodology and ELISA. Participants were followed up by linking them to registry data.

RESULTS

In the Discovery cohort (653 deaths; 216 CVD-related, 231 cancer-related), fully adjusted Cox proportional hazard regression models showed that increased plasma hepatocyte growth factor (HGF) and placental growth factor (PlGF) were associated with higher risk of 10-year mortality (HR, 1.29 [95% confidence interval (CI), 1.18-1.41] and HR, 1.23 [95% CI, 1.14-1.32], respectively). In the Replication cohort (259 deaths; 83 CVD-related, 90 cancer-related), baseline HGF levels also predicted all-cause mortality (HR, 1.2 [95% CI, 1.08-1.32]; PlGF data not available). By including HGF levels in a CVD mortality model, 9% of all CVD deaths were correctly reclassified in the Discovery cohort (categorical net reclassification improvement [NRI] for events, P = 4.0 × 10^-4 ). Moreover, adding HGF to all-cause and CVD mortality models resulted in an overall clinical NRI of 0.10-0.18 in the Discovery cohort and meta-analyses (P < 0.05 for all tests).

CONCLUSION

Blood levels of HGF and PlGF may serve as new biomarkers for predicting increased risk of death in the general population.

Biological and Pro-Angiogenic Properties of Genetically Modified Human Primary Myoblasts Overexpressing Placental Growth Factor in In Vitro and In Vivo Studies

Cardiovascular diseases are a growing problem in developing countries; therefore, there is an ongoing intensive search for new approaches to treat these disorders. Currently, cellular therapies are focused on healing the damaged heart by implanting stem cells modified with pro-angiogenic factors. This approach ensures that the introduced cells are capable of fulfilling the complex requirements of the environment, including the replacement of the post-infarction scar with cells that are able to contract and promote the formation of new blood vessels that can supply the ischaemic region with nutrients and oxygen. This study focused on the genetic modification of human skeletal muscle cells (SkMCs). We chose myoblast cells due to their close biological resemblance to cardiomyocytes and the placental growth factor (PlGF) gene due to its pro-angiogenic potential. In our in vitro studies, we transfected SkMCs with the PlGF gene using electroporation, which has previously been proven to be efficient and generate robust overexpression of the PlGF gene and elevate PlGF protein secretion. Moreover, the functionality of the secreted pro-angiogenic proteins was confirmed using an in vitro capillary development assay. We have also examined the influence of PlGF overexpression on VEGF-A and VEGF-B, which are well-known factors described in the literature as the most potent activators of blood vessel formation. We were able to confirm the overexpression of VEGF-A in myoblasts transfected with the PlGF gene. The results obtained in this study were further verified in an animal model. These data were able to confirm the potential therapeutic effects of the applied treatments.

Impact of Obstructive Sleep Apnea on the Levels of Placental Growth Factor (PlGF) and Their Value for Predicting Short-Term Adverse Outcomes in Patients with Acute Coronary Syndrome

BACKGROUND

Placental growth factor (PlGF) induces angiogenesis and promotes tissue repair, and plasma PlGF levels change markedly during acute myocardial infarction (AMI). Currently, the impact of obstructive sleep apnea (OSA) in patients with AMI is a subject of debate. Our objective was to evaluate the relationships between PlGF levels and both the severity of acute coronary syndrome (ACS) and short-term outcomes after ACS in patients with and without OSA.

METHODS

A total of 538 consecutive patients (312 OSA patients and 226 controls) admitted for ACS were included in this study. All patients underwent polygraphy in the first 72 hours after hospital admission. The severity of disease and short-term prognoses were evaluated during the hospitalization period. Plasma PlGF levels were measured using an electrochemiluminescence immunoassay.

RESULTS

Patients with OSA were significantly older and more frequently hypertensive and had higher BMIs than those without OSA. After adjusting for age, smoking status, BMI and hypertension, PlGF levels were significantly elevated in patients with OSA compared with patients without OSA (19.9 pg/mL, interquartile range: 16.6-24.5 pg/mL; 18.5 pg/mL, interquartile range: 14.7-22.7 pg/mL; p<0.001), and a higher apnea-hypopnea index (AHI) was associated with higher PlGF concentrations (p<0.003). Patients with higher levels of PlGF had also an increased odds ratio for the presence of 3 or more diseased vessels and for a Killip score>1, even after adjustment.

CONCLUSIONS

The results of this study show that in patients with ACS, elevated plasma levels of PlGF are associated with the presence of OSA and with adverse outcomes during short-term follow-up.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01335087.

Prognostic use of soluble fms-like tyrosine kinase-1 and placental growth factor in patients with coronary artery disease

Background: Intention of the study is to assess the cardiovascular mortality of patients with coronary artery disease (CAD) with the biomarkers of angiogenesis PlGF and its endogenous inhibitor sFlt-1. Methods: The cohort included n = 1848 patients with CAD and 282 subjects without CAD. In 85 patients cardiovascular mortality, as combination of fatal myocardial infarction or any cardiac death, during a median follow-up duration of 3.9 years was reported. Results: In Kaplan–Meier curve analysis PlGF in rising thirds was not predictive regarding outcome (p = 0.54), the same was shown for sFlt-1 (p = 0.44). Cox regression for the fully adjusted model provided a hazard ratio (HR) of 0.8 (p = 0.18) for PlGF and for sFlt-1 a HR = 1.0 (p = 0.8). Conclusion: Our results point out that these biomarkers reflecting angiogenesis might not be suited to establish prognosis in CAD.

Elevated Soluble Fms-Like Tyrosine Kinase-1 and Placental-Like Growth Factor Levels Are Associated With Development and Mortality Risk in Heart Failure

BACKGROUND

Vascular endothelial dysfunction may play an important role in the progression of heart failure (HF). We hypothesize that elevated levels of vascular markers, placental-like growth factor, and soluble Fms-like tyrosine kinase-1 (sFlt-1) are associated with adverse outcomes in patients with HF. We also assessed possible triggers of sFlt-1 elevation in animal HF models.

METHODS AND RESULTS

We measured plasma placental-like growth factor and sFlt-1 in 791 HF patients undergoing elective coronary angiogram. Median (interquartile range) placental-like growth factor and sFlt-1 levels were 24 (20-29) and 382 (277-953) pg/mL, respectively. After 5 years of follow-up, and after using receiver operator characteristic curves to determine optimal cutoffs, high levels of sFlt-1 (≥ 280 pg/mL; adjusted hazard ratio, 1.47; 95% confidence interval, 1.03-2.09; P=0.035) but not placental-like growth factor (≥ 25 pg/mL; adjusted hazard ratio, 1.26; 95% confidence interval, 0.94-1.71, P=0.12) were associated with adverse cardiovascular outcomes. In addition, significant elevation of sFlt-1 levels was observed in left anterior descending artery ligation and transverse aortic constriction HF mouse models after 4 and 8 weeks of follow-up, suggesting vascular stress and ischemia as triggers for sFlt-1 elevation in HF.

CONCLUSIONS

Circulating sFlt-1 is generated as a result of myocardial injury and subsequent HF development. Elevated levels of sFlt-1 are associated with adverse outcomes in stable patients with HF.

Systemic and coronary levels of CRP, MPO, sCD40L and PlGF in patients with coronary artery disease

BACKGROUND

Biomarkers play a pivotal role in the diagnosis and management of patients with acute coronary syndrome. This study aimed to investigate the differences in level of several biomarkers, i.e. C-reactive protein, myeloperoxidase, soluble CD40 ligand and placental growth factor, between acute coronary syndrome and chronic stable angina patients. The relationship between these biomarkers in the coronary circulation and systemic circulation was also investigated.

METHODS

A total of 79 patients were recruited in this study. The coronary blood was sampled from occluded coronary artery, while the peripheral venous blood was withdrawn from antecubital fossa. The serum concentrations of C-reactive protein, soluble CD40 ligand and placental growth factor and plasma concentration of myeloperoxidase were measured using ELISA method.

RESULTS

The systemic level of the markers measured in the peripheral venous blood was significantly increased in acute coronary syndrome compared to chronic stable angina patients. The concentrations of the C-reactive protein, myeloperoxidase and soluble CD40 ligand taken from peripheral vein were closely similar to the concentration found in coronary blood of ACS patients. The level of placental growth factor was significantly higher in coronary circulation than its systemic level.

CONCLUSION

The concentration of these C-reactive protein, myeloperoxidase, soluble CD40 ligand and placental growth factor were significantly increased in acute coronary syndrome patients. The concentration of the markers measured in the systemic circulation directly reflected those in the local coronary circulation. Thus, these markers have potential to become a useful tool in predicting plaque vulnerability in the future.

Fluid shear stress upregulates placental growth factor in the vessel wall via NADPH oxidase 4

Placental growth factor (PLGF), a potent stimulator of arteriogenesis, is upregulated during outward arterial remodeling. Increased fluid shear stress (FSS) is a key physiological stimulus for arteriogenesis. However, the role of FSS in regulating PLGF expression is unknown. To test the hypothesis that FSS regulates PLGF expression in vascular cells and to identify the signaling pathways involved, human coronary artery endothelial cells (HCAEC) and human coronary artery smooth muscle cells were cultured on either side of porous Transwell inserts. HCAEC were then exposed to pulsatile FSS of 0.07 Pa ("normal," mimicking flow through quiescent collaterals), 1.24 Pa ("high," mimicking increased flow in remodeling collaterals), or 0.00 Pa ("static") for 2 h. High FSS increased secreted PLGF protein ∼1.4-fold compared with static control (n = 5, P < 0.01), while normal FSS had no significant effect on PLGF. Similarly, high flow stimulated PLGF mRNA expression nearly twofold in isolated mouse mesenteric arterioles. PLGF knockdown using siRNA revealed that HCAEC were the primary source of PLGF in cocultures (n = 5, P < 0.01). Both H2O2 and nitric oxide production were increased by FSS compared with static control (n = 5, P < 0.05). N(G)-nitro-l-arginine methyl ester (100 μM) had no significant effect on the FSS-induced increase in PLGF. In contrast, both catalase (500 U/ml) and diphenyleneiodonium (5 μM) attenuated the effects of FSS on PLGF protein in cocultures. Diphenyleneiodonium also blocked the effect of high flow to upregulate PLGF mRNA in isolated arterioles. Further studies identified NADPH oxidase 4 as a source of reactive oxygen species for this pathway. We conclude that FSS regulates PLGF expression via NADPH oxidase 4 and reactive oxygen species signaling.

Prognostic Impact of Placental Growth Factor on Mortality and Cardiovascular Events in Dialysis Patients

BACKGROUND

Placental growth factor (PlGF), a member of the vascular endothelial growth factor (VEGF) family, has recently emerged as a predictor of survival and cardiovascular risk. Along with others, we have shown an independent association between PlGF and cardiovascular events in CKD patients, but not much is known about patients receiving dialysis.

METHODS

We studied 205 dialysis patients undergoing cardiac catheterization at the Nara Medical University between April 1, 2004, and December 31, 2012. Serum levels of PlGF and VEGF were measured with ELISA in all the patients.

RESULTS

During a median follow-up of 20 months, 121 participants died from any cause or experienced a cardiovascular event. In the fully adjusted analysis, having an above-median PlGF or VEGF level was associated with a hazards ratio for adverse outcomes of 2.55 (1.72-3.83) and 1.39 (0.95-2.04), respectively. Using a multimarker strategy in a model with age, serum albumin, history of coronary artery disease, brain natriuretic peptide and PlGF, patients with 2, 3 and 4 positive markers had a 3.82-, 5.77- and 6.59-fold higher risk of mortality or a cardiovascular event, respectively, compared to those with no positive markers. The model with PlGF had a significantly higher c-statistic, integrated discrimination improvement index and category-free net reclassification improvement index than the model without PlGF.

CONCLUSION

PlGF is independently associated with mortality and cardiovascular events, but the association between VEGF and adverse events was attenuated with covariate adjustment. The addition of PlGF to models with established clinical predictors provides additional useful prognostic information in patients receiving dialysis.

Low Serum Neutrophil Gelatinase-associated Lipocalin Level as a Marker of Malnutrition in Maintenance Hemodialysis Patients

Background

Neutrophil gelatinase-associated lipocalin (NGAL or LCN2) is an iron-transporting factor which possesses various activities such as amelioration of kidney injury and host defense against pathogens. Its circulating concentrations are elevated in acute and chronic kidney diseases and show a positive correlation with poor renal outcome and mortality, but its clinical significance in maintenance hemodialysis (HD) patients remains elusive.

Methods

Serum NGAL levels were determined by enzyme-linked immunosorbent assay in out-patient, Japanese HD subjects. Their correlation to laboratory findings and morbidity (as development of severe infection or serum albumin reduction) was investigated using linear regression analysis and χ² test.

Results

Pre-dialysis serum NGAL levels in HD patients were elevated by 13-fold compared to healthy subjects (n=8, P<0.001). In a cross-sectional study of 139 cases, serum NGAL concentrations were determined independently by % creatinine generation rate (an indicator of muscle mass, standardized coefficient β=0.40, P<0.001), peripheral blood neutrophil count (β=0.38, P<0.001) and anion gap (which likely reflects dietary protein intake, β=0.16, P<0.05). Iron administration to anemic HD patients caused marked elevation of peripheral blood hemoglobin, serum ferritin and iron-regulatory hormone hepcidin-25 levels, but NGAL levels were not affected. In a prospective study of 87 cases, increase in serum albumin levels a year later was positively associated to baseline NGAL levels by univariate analysis (r=0.36, P<0.01). Furthermore, within a year, patients with the lowest NGAL tertile showed significantly increased risk for marked decline in serum albumin levels (≥0.4 g/dl; odds ratio 5.5, 95% confidence interval 1.5–20.3, P<0.05) and tendency of increased occurrence of severe infection requiring admission (odds ratio 3.1, not significant) compared to the middle and highest tertiles.

Conclusion

Low serum NGAL levels appear to be associated with current malnutrition and also its progressive worsening in maintenance HD patients.

Cell type- and tumor zone-specific expression of pVEGFR-1 and its ligands influence colon cancer metastasis

Background

Detailed knowledge of the essential pro-angiogenic biomolecules, the vascular endothelial growth factor (VEGF) family and its receptors, in the characteristically heterogeneous tumor tissue is a pre-requisite for an effective personalized target therapy. The effects of VEGF receptors after ligand binding are mediated through receptor tyrosine autophosphorylation. We determined the relevance of the VEGFR-1 activating pathway for colon cancer (CC) metastasis.

Methods

The expression profiles of VEGFR-1, phosphorylated (activated) VEGFR-1 (pVEGFR-1^Tyr1048, pVEGFR-1^Tyr1213 and pVEGFR-1^Tyr1333) and the VEGFR-1 ligands (VEGF, PlGF and VEGF-B) were investigated using immunohistochemistry in different tumor compartments (intratumoral - invasive front - extratumoral), cell types (tumor cells – macro- (large and small vessels) and the microvasculature (capillaries) - inflammatory cells) in human sporadic non-metastatic, lymphogenous metastatic and haematogenous metastatic CC.

Results

VEGF and PlGF produced by tumor cells have an autocrine affinity for their receptor VEGFR-1. Subsequent PlGF-mediated receptor activation by autophosphorylation at Tyr1048 and Tyr1213 is a potential signaling pathway, which in turn seems to protect against distant metastasis and, in regions of tumor budding, additionally against lymph node metastasis. This autocrine link could be supported by possible formation of PlGF-VEGF heterodimers and PlGF-PlGF homodimers, which are known to have anti-metastatic properties. In contrast, in order to enhance their potential for distant metastasis tumor cells produce paracrine-acting VEGF-B. VEGFR-1 activation in tumor-associated macrovasculature but not capillaries appears to affect metastatic ability. Paracrine-mediated receptor autophosphorylation at Tyr1048 and Tyr1213 in small vessels located intratumorally and along the invasive front appears to be inversely correlated with metastasis, especially distant metastasis. Additionally, macrovessels are able to produce VEGFR-1 ligands, which influence the metastatic potential. Paracrine-acting VEGF-B production by intratumorally located small vessels and autocrine-acting PlGF production by extratumorally located small vessels seem to be associated with the non-metastatic phenotype. In contrast, VEGF-B-expressing extratumoral large and small vessels correlate with distant metastasis. Lymphocyte-associated VEGFR-1 expression in the invasive front without accompanying autophosphorylation could prevent against distant metastasis possibly by acting as a decoy and scavenger receptor.

Conclusion

VEGFR-1 and its ligands participate in vascular, tumor cell-mediated and immuno-inflammatory processes in a complex biomolecule-dependent and tumor zone-specific manner and hence could influence metastatic behavior in CC.

Placental growth factor influences maternal cardiovascular adaptation to pregnancy in mice

In healthy human pregnancies, placental growth factor (PGF) concentrations rise in maternal plasma during early gestation, peak over Weeks 26-30, then decline. Because PGF in nongravid subjects participates in protection against and recovery from cardiac pathologies, we asked if PGF contributes to pregnancy-induced maternal cardiovascular adaptations. Cardiovascular function and structure were evaluated in virgin, pregnant, and postpartum C56BL/6-Pgf(-) (/) (-) (Pgf(-) (/) (-)) and C57BL/6-Pgf(+/+) (B6) mice using plethysmography, ultrasound, quantitative PCR, and cardiac and renal histology. Pgf(-/-) females had higher systolic blood pressure in early and late pregnancy but an extended, abnormal midpregnancy interval of depressed systolic pressure. Pgf(-/-) cardiac output was lower than gestation day (gd)-matched B6 after midpregnancy. While Pgf(-) (/) (-) left ventricular mass was greater than B6, only B6 showed the expected gestational gain in left ventricular mass. Expression of vasoactive genes in the left ventricle differed at gd8 with elevated Nos expression in Pgf(-) (/) (-) but not at gd14. By gd16, Pgf(-) (/) (-) kidneys were hypertrophic and had glomerular pathology. This study documents for the first time that PGF is associated with the systemic maternal cardiovascular adaptations to pregnancy.

Improvement of risk assessment in systemic light-chain amyloidosis using human placental growth factor

BACKGROUND

Vascular amyloid deposition is common in light-chain amyloidosis resulting in endothelial dysfunction. Human placental growth factor (PlGF), a member of the vascular endothelial growth factor family was found to be altered in diverse pathological conditions, e.g. endothelial dysfunction. This study evaluated the clinical role of PlGF in light-chain amyloidosis.

METHODS

PlGF (cobas-PlGF, Roche Diagnostics, Mannheim, Germany) was analyzed in 125 consecutive patients with AL and correlated with diverse clinical parameters including mortality.

RESULTS

Kidney (n = 76) and heart (n = 57) were predominantly affected by amyloid deposition. Median PlGF was 26.3 (21.1-42.1) ng/L, NT-proBNP 3649 (1124-8581) pg/mL, and hs-TnT 42 (21-107) ng/L. PlGF increased with number of organs involved and with deterioration of renal function. A significant correlation of PlGF with hs-TnT (ρ = 0.306; p = 0.0007) and NT-proBNP (ρ = 0.315; p = 0.0006) was observed, but no correlation was observed with clinical, echocardiography, and electrocardiography parameters of cardiac involvement. In this cohort 1-year all-cause mortality was 19.2 %. The best cutoff discriminating survivors and non-survivors was 28.44 ng/L (sensitivity 66.7 %; specificity 78.1 %). A three-step risk model including hs-TnT and NT-proBNP revealed a better discrimination if patients at intermediary risk were additionally stratified by PlGF. Net reclassification index was 37.2 % (p = 0.002). Multivariate analysis revealed PlGF, difference of involved and uninvolved light chain, number of organs involved and risk class according to troponin T and NT-proBNP as independent predictors of mortality.

CONCLUSION

Plasma PlGF values in AL are invariably associated with the number of involved organs, but not with clinical, echocardiography, and electrocardiography parameters of cardiac involvement. PlGF provide useful information for risk stratification of patients at intermediary risk according to hs-TnT and NT-proBNP.

Panel of emerging cardiac biomarkers contributes for prognosis rather than diagnosis in chronic heart failure

Background: As complex disease, heart failure is associated with various pathophysiological and biochemical disorders. No single biomarker is able to display all these characteristics. Therefore, we evaluated a multimarker panel together with the biochemical gold-standard NT-proBNP. Part of the panel are markers for angiogenesis (Endostatin, IBP-4, IBP-7, sFlt-1 as antiangiogenetic factors and PLGF as angiogenectic factor), myocyte stress (GDF-15), extracellular matrix remodelling (galectin-3, mimecan and TIMP-1), inflammation (galectin-3) and myocyte injury (hs-TnT). Methods: All markers (Roche Diagnostics, Penzberg, Germany) were assessed in a cohort of 149 patients with chronic heart failure and 84 healthy controls. Results: All markers were positively correlated with ln NT-proBNP (each p < 0.05). Furthermore, they were significantly elevated in patients with chronic heart failure (each p < 0.05). All markers increased significantly with severity of LV dysfunction and severity of New York Heart Association class (each p < 0.05), except for PLGF and Mimecan (each p = NS). With the exception of endostatin, mimecan and PLGF, all other markers were further significant predictors for all-cause mortality in a 3-year follow-up. In a multimarker approach of the five biomarkers with the best performance (NT-proBNP, hs-TnT, TIMP-1, GDF-15 and IBP-4), the event rate was superior to NT-proBNP alone and increased significantly and progressively with the number of elevated biomarkers. Conclusion: All emerging markers increased stepwise with the severity of symptoms and LV dysfunction and offer important prognostic information in chronic heart failure, except for PLGF and mimecan. Five biomarkers with different pathophysiological background incorporated additive prognostic value in heart failure. Prognostication in heart failure may be further improved through a multimarker approach.

Melusin protects from cardiac rupture and improves functional remodelling after myocardial infarction

Aims

Melusin is a muscle-specific chaperone protein whose expression is required for a compensatory hypertrophy response to pressure overload. Here, we evaluated the consequences of melusin overexpression in the setting of myocardial infarction (MI) using a comprehensive multicentre approach.

Methods and results

Mice overexpressing melusin in the heart (TG) and wild-type controls (WT) were subjected to permanent LAD ligation and both the acute response (Day 3) and subsequent remodelling (2 weeks) were examined. Mortality in wild-type mice was significant between Days 3 and 7, primarily due to cardiac rupture, but melusin's overexpression strongly reduced mortality (43.2% in wild-type vs. 27.3% in melusin-TG, P = 0.005). At Day 3 after MI, a time point preceding the mortality peak, TG hearts had increased heat shock protein 70 expression, increased ERK1/2 signalling, reduced cardiomyocyte hyper-contractility and inflammatory cell infiltrates, and increased matricellular protein expression in the infarcted area.

At 2 weeks after MI, melusin overexpression conferred a favourable adaptive remodelling characterized by reduced left ventricle dilatation and better preserved contractility in the presence of a comparable degree of hypertrophy. Adaptive remodelling in melusin TG mice was characterized by reduced apoptosis and fibrosis as well as increased cardiomyocyte contractility.

Conclusions

Consistent with its function as a chaperone protein, melusin overexpression exerts a dual protective action following MI reducing an array of maladaptive processes. In the early phase after MI, reduced inflammation and myocyte remodelling protect against cardiac rupture. Chronically, reduced myocyte loss and matrix remodelling, with preserved myocyte contractility, confer adaptive LV remodelling.

Placenta growth factor mediates angiogenesis in hypoxic pulmonary hypertension

Our previous studies have proved that hypoxia enhances the 15-lipoxygenase (15-LO) expression and increases endogenous 15-hydroxyeicosatetraenoic acid (15-HETE) production to promote pulmonary vascular remodeling and angiogenesis, while the mechanisms of how hypoxia regulates 15-LO expression in endothelium is still unknown. As placenta growth factor (PlGF) promotes pathological angiogenesis by acting on the growth, migration and survival of endothelial cells, there may be some connections between PlGF and 15-LO in hypoxia induced endothelial cells proliferation. In this study, we performed immunohistochemistry, pulmonary artery endothelial cells migration and bromodeoxyuridine incorporation to determine the role of PlGF in pulmonary remodeling induced by hypoxia. Our results showed that hypoxia up-regulated PlGF expression, which was mediated by 15-LO/15-HETE pathway. Furthermore, we found that PlGF had a positive feedback regulation with 15-LO expression and 15-HETE generation. The interaction in hypoxia between 15-HETE and PlGF created a PlGF-15-LO-15-HETE loop, leading to endothelial dysfunction. Thus, these findings suggest a new therapeutic agent in combination with the blockade of PlGF as well as 15-LO in hypoxic pulmonary hypertension.

Soluble Fms-like tyrosine kinase 1 is a novel predictor of brain natriuretic peptide elevation

Soluble fms-like tyrosine kinase 1 (sFlt-1) is an endogenous inhibitor of vascular endothelial growth factor, which is involved in cardiovascular remodeling and atherosclerosis development. To examine the predictive role of sFlt-1 levels in patients with asymptomatic heart failure, we measured circulating sFlt-1 in patients with or without coronary artery disease (CAD). We analyzed 88 Japanese patients with CAD or patients at high risk for atherosclerosis and who were undergoing total risk management for cardiovascular disease prevention. Circulating sFlt-1 levels correlated with the increase in plasma brain natriuretic peptide levels (ΔBNP) from baseline to the observed levels 5 years later in CAD patients, patients with previous myocardial infarction, and men. ΔBNP levels correlated with sFlt-1 levels in the high-sFlt-1 patients with CAD (r = 0.511, P < 0.01). In all patients, end-systolic volume index (ΔESVI) increased in correlation with a decrease in left ventricular ejection fraction (ΔEF) in the long-term observation, independent of their history of myocardial infarction (ΔESVI = 2.5 mL/m(2) increase/year). Baseline level of sFlt-1 was independent of ΔESVI or ΔEF. The present 5-year observational study demonstrated that high sFlt-1 levels predicted moderate increases in BNP levels in CAD patients. Moreover, ΔBNP was correlated with ΔESVI/year in CAD patients with high-sFlt-1 levels. These data suggest that high sFlt-1 levels may be an effective biomarker to predict the progression of heart failure in patients with CAD.

Vascular endothelial growth factor in heart failure

Heart failure is a devastating condition, the progression of which culminates in a mismatch of oxygen supply and demand, with limited options for treatment. Heart failure has several underlying causes including, but not limited to, ischaemic heart disease, valvular dysfunction, and hypertensive heart disease. Dysfunctional blood vessel formation is a major problem in advanced heart failure, regardless of the aetiology. Vascular endothelial growth factor (VEGF) is the cornerstone cytokine involved in the formation of new vessels. A multitude of investigations, at both the preclinical and clinical levels, have garnered valuable information on the potential utility of targeting VEGF as a treatment option for heart failure. However, clinical trials of VEGF gene therapy in patients with coronary artery disease or peripheral artery disease have not, to date, demonstrated clinical benefit. In this Review, we outline the biological characterization of VEGF, and examine the evidence for its potential therapeutic application, including the novel concept of VEGF as adjuvant therapy to stem cell transplantation, in patients with heart failure.

Placental growth factor as a protective paracrine effector in the heart

In response to injury, the myocardium hypertrophies in an attempt to maintain or augment function, which is associated with ventricular remodeling and changes in capillary density. During the compensatory phase of the hypertrophic response, the myocardium maintains output and is characterized by a coordinated neo-angiogenic and fibrotic response that supports cardiomyocyte health and survival. Emerging evidence shows that paracrine-mediated cross talk between cardiac myocytes and nonmyocytes within the heart is critical for cardiac adaptation to stress, including the extent of hypertrophy and angiogenesis. This review discusses recent results indicating that placental growth factor (PGF; also called PlGF), a secreted factor within the vascular endothelial growth factor superfamily, is a pivotal mediator of adaptive cardiac hypertrophy and beneficial angiogenesis through its ability to coordinate the intercellular communication between different cell types in the heart.

Placental growth factor increases regional myocardial blood flow and contractile function in chronic myocardial ischemia

Placental growth factor (PlGF) has a distinct biological phenotype with a predominant proangiogenic role in disease without affecting quiescent vessels in healthy organs. We tested whether systemic administration of recombinant human (rh)PlGF improves regional myocardial blood flow (MBF) and systolic function recovery in a porcine chronic myocardial ischemia model. We implanted a flow-limiting stent in the proximal left anterior descending coronary artery and measured systemic hemodynamics, regional myocardial function using MRI, and blood flow using colored microspheres 4 wk later. Animals were then randomized in a blinded way to receive an infusion of rhPlGF (15 μg·kg(-1)·day(-1), n = 9) or PBS (control; n = 10) for 2 wk. At 8 wk, myocardial perfusion and function were reassessed. Infusion of rhPlGF transiently increased PlGF serum levels >30-fold (1,153 ± 180 vs. 33 ± 18 pg/ml at baseline, P < 0.001) without affecting systemic hemodynamics. From 4 to 8 wk, rhPlGF increased regional MBF from 0.46 ± 0.11 to 0.85 ± 0.16 ml·min(-1)·g(-1), with a concomitant increase in systolic wall thickening from 11 ± 3% to 26 ± 5% in the ischemic area. In control animals, no significant changes from 4 to 8 wk were observed (MBF: 0.45 ± 0.07 to 0.49 ± 0.08 ml·min(-1)·g(-1) and systolic wall thickening: 14 ± 4% to 18 ± 1%). rhPlGF-induced functional improvement was accompanied by increased myocardial neovascularization, enhanced glycogen utilization, and reduced oxidative stress and cardiomyocyte apoptosis in the ischemic zone. In conclusion, systemic rhPlGF infusion significantly enhances regional blood flow and contractile function of the chronic ischemic myocardium without adverse effects. PlGF protein infusion may represent an attractive therapeutic strategy to increase myocardial perfusion and energetics in chronic ischemic cardiomyopathy.

An elevated ratio of placental growth factor to soluble fms-like tyrosine kinase-1 predicts adverse outcomes in patients with stable coronary artery disease

OBJECTIVE

To investigate the predictive values of placental growth factor (PlGF) and its endogenous antagonist, soluble fms-like tyrosine kinase-1 (sFlt-1), for the long-term prognosis of patients with stable coronary artery disease (CAD). Both PlGF and sFlt-1 play important roles in the pathological mechanisms of atherosclerosis. We recently demonstrated that the plasma levels of these molecules are correlated with the severity of coronary atherosclerosis.

METHODS

We enrolled 464 patients with stable CAD who consecutively underwent coronary angiography. Baseline blood samples were collected from the femoral artery immediately before coronary angiography (after the administration of 20 units of heparin), and the plasma levels of PlGF and sFlt-1 were measured. A Cox proportional hazard regression analysis was performed to evaluate the relationship between these parameters and the occurrence of all-cause death (ACD) and total cardiovascular events (TCVE) during a median follow-up of 3.3 years.

RESULTS

A total of 31 ACDs and 51 TCVEs occurred. Patients with higher PlGF/sFlt-1 ratios (>4.22×10(-2)) had a significantly higher risk of both ACD and TCVE than patients with lower ratios (<4.22×10(-2)) (hazard ratio [HR]: 3.32, 95% confidence interval [CI]: 1.43 to 7.72, p=0.005, and HR: 2.23, 95% CI: 1.23 to 4.03, p=0.008, respectively). A multivariate analysis showed the PlGF/sFlt-1 ratio to be an independent predictor for ACD, but not TCVE.

CONCLUSION

The baseline PlGF/sFlt-1 ratio is an independent predictor of long-term adverse outcomes in patients with stable CAD.

Elevated concentration of placental growth factor (PlGF) and long term risk in patients with acute coronary syndrome in the PROVE IT-TIMI 22 trial

Placental growth factor (PlGF), a member of the vascular endothelial growth factor (VEGF) family, acts via the flt-1 receptor and promotes endothelial activation and macrophage recruitment into atherosclerotic lesions. We investigated the relationship of PlGF with cardiovascular outcomes in a large cohort of patients presenting across the spectrum of ACS. PlGF was measured at baseline (n = 3,761) and at four-months (n = 3,369) in patients randomized to atorvastatin 80 mg or pravastatin 40 mg after ACS in the PROVE IT-TIMI 22 trial. The primary endpoint was death, myocardial infarction (MI), unstable angina, revascularization or stroke (mean follow-up 24 months). Elevated baseline PlGF was associated with a higher incidence of the primary endpoint through 2 years (Q1 vs. Q5: 18.7 vs. 29.3%, p < 0.0001). The risk of death or MI was also higher in patients with elevated baseline PlGF (Q1 vs. Q5: 7.0 vs. 11.6%, p = 0.029). Adjusting for baseline characteristics and risk factors, elevated baseline PlGF was independently associated with the risk of the primary endpoint (adjusted-HR for Q5 vs. Q1 1.45; 95% CI 1.16-1.83; p = 0.001). Elevated PlGF at four months was associated with higher risk of death or MI (Adjusted HR Q5 vs. Q1 2.79, 95% CI: 1.37-5.68; p = 0.005), and higher risk of the primary endpoint (Adjusted HR Q5 vs. Q1 1.78, 95% CI: 1.26-2.51; p = 0.001). Higher concentration of PlGF after ACS is associated with long-term risk of recurrent cardiovascular events independent of traditional risk factors. This association is present early after ACS and appears to be stronger at four months.

PlGF: a multitasking cytokine with disease-restricted activity

Placental growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family that also comprises VEGF-A (VEGF), VEGF-B, VEGF-C, and VEGF-D. Unlike VEGF, PlGF is dispensable for development and health but has diverse nonredundant roles in tissue ischemia, malignancy, inflammation, and multiple other diseases. Genetic and pharmacological gain-of-function and loss-of-function studies have identified molecular mechanisms of this multitasking cytokine and characterized the therapeutic potential of delivering or blocking PlGF for various disorders.

Evaluation of placental growth factor and soluble Fms-like tyrosine kinase 1 as predictors of all-cause and cardiovascular mortality in patients with Type 1 diabetes with and without diabetic nephropathy

AIMS

Placental growth factor is a vascular endothelial growth factor involved in angiogenesis, vascular inflammation and plaque formation. Soluble Fms-like tyrosine kinase 1 is a decoy receptor for placental growth factor, reducing its activity. The aim of this study is to evaluate the predictive value of placental growth factor and soluble Fms-like tyrosine kinase 1 in relation to all-cause and cardiovascular mortality and decline in kidney function in Type 1 diabetes.

METHODS

This was a prospective, observational follow-up study with 8 (0-13) years [median (range)] of follow-up, including patients with Type 1 diabetes, of whom 458 had diabetic nephropathy [278 men; age 42 ± 11 years (mean ± sd), diabetes duration 28 ± 9 years, glomerular filtration rate 76 ± 33 ml min(-1) 1.73 m(-2) ] and 442 had long-standing normoalbuminuria (234 men; age 45 ± 12 years, diabetes duration 28 ± 10 years).

RESULTS

Placental growth factor and soluble Fms-like tyrosine kinase 1 levels measured at baseline were higher in patients with diabetic nephropathy compared with patients with long-standing normoalbuminuria [median (range)] 15 (4-131) vs. 11 (7-64) ng/l, (P < 0.001) and 86 (42-3462) vs. 77 (43-1557) ng/l (P < 0.001), respectively. In patients with diabetic nephropathy, high levels of placental growth factor predicted all-cause and cardiovascular mortality [hazard ratio 1.94 (1.16-3.24) and hazard ratio 2.91 (1.45-5.85)] after adjustment for sex, age, smoking, systolic blood pressure, HbA(1c) , cholesterol, glomerular filtration rate and previous cardiovascular disease. High levels of placental growth factor predicted increased risk of end-stage renal disease [hazard ratio 2.77 (1.47-5.14)], but covariate adjustments attenuated the association [hazard ratio 1.89 (0.91-3.95)]. Among patients with long-standing normoalbuminuria, placental growth factor levels predicted fatal and non-fatal cardiovascular events [hazard ratio 1.97 (1.03-3.76)], but not all-cause mortality. Baseline soluble Fms-like tyrosine kinase 1 levels did not predict outcome in either group after adjustment.

CONCLUSION

Placental growth factor is elevated in patients with Type 1 diabetes and diabetic nephropathy and predicts all-cause and cardiovascular mortality, but not deterioration of kidney function.

Cardiac biomarkers in acute myocardial infarction

Each year, a large number of patients are seen in the Emergency Department with presentations necessitating investigation for possible acute myocardial infarction. Patients can be stratified by symptoms, risk factors and electrocardiogram results but cardiac biomarkers also have a prime role both diagnostically and prognostically. This review summarizes both the history of cardiac biomarkers as well as currently available (established and novel) assays. Cardiac troponin, our current "gold standard" biomarker criterion for the diagnosis of myocardial infarction has high sensitivity and specificity for this diagnosis and therapies instituted in patients with elevated troponin have been shown to influence outcomes. Other markers of myocardial necrosis, inflammation and neurohormonal activity have also been shown to have either diagnostic or prognostic utility, but none have been shown to be superior to troponin. The measurement of multiple biomarkers and the use of point of care markers may accelerate current diagnostic protocols for the assessment of such patients.

The vascular marker soluble fms-like tyrosine kinase 1 is associated with disease severity and adverse outcomes in chronic heart failure

OBJECTIVES

We sought to evaluate placental growth factor (PlGF) and soluble Fms-like tyrosine kinase 1 (sFlt-1) as clinical biomarkers in chronic heart failure (HF).

BACKGROUND

Vascular remodeling is a crucial compensatory mechanism in chronic HF. The angiogenic ligand PlGF and its target receptor fms-like tyrosine kinase 1 modulate vascular growth and function, but their relevance in human HF is undefined.

METHODS

We measured plasma PlGF and sFlt-1 in 1,403 patients from the Penn Heart Failure Study, a multicenter cohort of chronic systolic HF. Subjects were followed for death, cardiac transplantation, or ventricular assist device placement over a median follow-up of 2 years.

RESULTS

The sFlt-1 was independently associated with measures of HF severity, including New York Heart Association functional class (p < 0.01) and B-type natriuretic peptide (p < 0.01). Patients in the 4th quartile of sFlt-1 (>379 pg/ml) had a 6.17-fold increased risk of adverse outcomes (p < 0.01). This association was robust, even after adjustment for the Seattle Failure Model (hazard ratio: 2.54, 95% confidence interval [CI]: 1.76 to 2.27, p < 0.01) and clinical confounders including HF etiology (hazard ratio: 1.67, 95% CI: 1.06 to 2.63, p = 0.03). Combined assessment of sFlt-1 and B-type natriuretic peptide exhibited high predictive accuracy at 1 year (area under the receiver-operator characteristic curve: 0.791, 95% CI: 0.752 to 0.831) that was greater than either marker alone (p < 0.01 and p = 0.03, respectively). In contrast, PlGF was not an independent marker of disease severity or outcomes.

CONCLUSIONS

Our findings support a role for sFlt-1 in the biology of human HF. With additional study, circulating sFlt-1 might emerge as a clinically useful biomarker to assess the influence of vascular remodeling on clinical outcomes.

PlGF repairs myocardial ischemia through mechanisms of angiogenesis, cardioprotection and recruitment of myo-angiogenic competent marrow progenitors

RATIONALE

Despite preclinical success in regenerating and revascularizing the infarcted heart using angiogenic growth factors or bone marrow (BM) cells, recent clinical trials have revealed less benefit from these therapies than expected.

OBJECTIVE

We explored the therapeutic potential of myocardial gene therapy of placental growth factor (PlGF), a VEGF-related angiogenic growth factor, with progenitor-mobilizing activity.

METHODS AND RESULTS

Myocardial PlGF gene therapy improves cardiac performance after myocardial infarction, by inducing cardiac repair and reparative myoangiogenesis, via upregulation of paracrine anti-apoptotic and angiogenic factors. In addition, PlGF therapy stimulated Sca-1(+)/Lin(-) (SL) BM progenitor proliferation, enhanced their mobilization into peripheral blood, and promoted their recruitment into the peri-infarct borders. Moreover, PlGF enhanced endothelial progenitor colony formation of BM-derived SL cells, and induced a phenotypic switch of BM-SL cells, recruited in the infarct, to the endothelial, smooth muscle and cardiomyocyte lineage.

CONCLUSIONS

Such pleiotropic effects of PlGF on cardiac repair and regeneration offer novel opportunities in the treatment of ischemic heart disease.

Placental growth factor regulates cardiac adaptation and hypertrophy through a paracrine mechanism

RATIONALE

Paracrine growth factor-mediated crosstalk between cardiac myocytes and nonmyocytes in the heart is critical for programming adaptive cardiac hypertrophy in which myocyte size, capillary density, and the extracellular matrix function coordinately.

OBJECTIVE

To examine the role that placental growth factor (PGF) plays in the heart as a paracrine regulator of cardiac adaptation to stress stimulation.

METHODS AND RESULTS

PGF is induced in the heart after pressure-overload stimulation, where it is expressed in both myocytes and nonmyocytes. We generated cardiac-specific and adult inducible PGF-overexpressing transgenic mice and analyzed Pgf(-/-) mice to examine the role that this factor plays in cardiac disease and paracrine signaling. Although PGF transgenic mice did not have a baseline phenotype or a change in capillary density, they did exhibit a greater cardiac hypertrophic response, a greater increase in capillary density, and increased fibroblast content in the heart in response to pressure-overload stimulation. PGF transgenic mice showed a more adaptive type of cardiac growth that was protective against signs of failure with pressure overload and neuroendocrine stimulation. Antithetically, Pgf(-/-) mice rapidly died of heart failure within 1 week of pressure overload, they showed an inability to upregulate angiogenesis, and they showed significantly less fibroblast activity in the heart. Mechanistically, we show that PGF does not have a direct effect on cardiomyocytes but works through endothelial cells and fibroblasts by inducing capillary growth and fibroblast proliferation, which secondarily support greater cardiac hypertrophy through intermediate paracrine growth factors such as interleukin-6.

CONCLUSIONS

PGF is a secreted factor that supports hypertrophy and cardiac function during pressure overload by affecting endothelial cells and fibroblasts that in turn stimulate and support the myocytes through additional paracrine factors.