Pericardial fluid and serum levels of vascular endothelial growth factor and endostatin in patients with or without coronary artery disease

Identification of Endoplasmic Reticulum Stress-Related Biomarkers in Coronary Artery Disease

Coronary artery disease (CAD) is caused by atherosclerotic lesions in the coronary vessels. Endoplasmic reticulum stress (ERS) acts in cardiovascular disease, and its role in CAD is not clear. A total of 13 differentially expressed ERS-related genes (DEERSRGs) in CAD were identified. Functional enrichment analysis demonstrated the DEERSRGs were mainly enriched in endoplasmic reticulum (ER)-related pathways. Then, eight genes (RCN2, HRC, DERL2, RNF183, CRH, TMED2, PPP1R15A, and IL1A) were authenticated as ERS-related biomarkers in CAD by least absolute shrinkage and selection operator (LASSO). The receiver operating characteristic (ROC) analysis showed that the LASSO logistic model constructed based on biomarkers had a better diagnostic effect, which was confirmed by the ANN and GSE23561 datasets. Also, ROC results showed that seven of the eight biomarkers had better diagnostic effects. The nomogram model had good predictive power, and biomarkers were mostly enriched in pathways associated with CAD. The biomarkers were significantly associated with 10 immune cells, and RCN2, DERL2, TMED2, and RNF183 were negatively correlated with most chemokines. Eight biomarkers had significant correlations with both immunoinhibitors and immunostimulators. In addition, eight biomarkers were significantly different in both CAD and control samples, CRH and HRC were upregulated in CAD. The quantitative reverse transcription-polymerase chain reaction (qRT-PCR) showed that RCN2, HRC, DERL2, CRH, and IL1A were consistent with the bioinformatics analysis. RCN2, HRC, DERL2, RNF183, CRH, TMED2, PPP1R15A, and IL1A were identified as biomarkers of CAD. Functional enrichment analysis and immunoassays for biomarkers provide new ideas for the treatment of CAD.

Pericardial fluid troponin in cardiac surgery

BACKGROUND AND OBJECTIVE

Pericardial Fluid (PF) is a rich reservoir of biologically active factors. Due to its proximity to the heart, the biochemical structure of PF may reflect the pathological changes in the cardiac interstitial environment. This manuscript aimed to determine whether the PF level of cardiac troponins changes in patients undergoing cardiac surgery.

METHODS

This scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Medline, EMBASE, Cochrane, ClinicalTrials.gov, and Google Scholar databases were electronically searched for primary studies using the keywords "pericardial fluid," "troponin," and "cardiac surgery." The primary outcome of interest was changes in troponin levels within the PF preoperatively and postoperatively. Secondary outcomes of interest included comparisons between troponin level changes in the PF compared to plasma.

RESULTS

A total of 2901 manuscripts were screened through a title and abstract stage by two independent blinded reviewers. Of those, 2894 studies were excluded, and the remaining seven studies underwent a full-text review. Studies were excluded if they did not provide data or failed to meet inclusion criteria. Ultimately, six articles were included that discussed cardiac troponin levels within the PF in patients who had undergone cardiac surgery. Pericardial troponin concentration increased over time after surgery, and levels were significantly higher in PF compared to serum. All studies found that the type of operation did not affect these overall observations.

CONCLUSION

Our review of the literature suggest that the PF level of cardiac troponins increases in patients undergoing cardiac surgery, irrespective of the procedure type. However, these changes' exact pattern and clinical significance remain undefined.

Accumulation of Inflammatory Mediators in the Normal Pericardial Fluid

There is paucity of studies that focus on the composition of pericardial fluid under resting conditions. The purpose of this study is to determine the levels of inflammatory mediators in pericardial fluid and their correlation with plasma levels in patients undergoing elective cardiac surgery. We conducted a prospective cohort study on candidates for elective aortic valve replacement surgery. Pericardial fluid and peripheral venous blood samples were collected after opening the pericardium. Levels of interleukin 1α (IL-1α); interleukin 1β (IL-1β); interleukin 2 (IL-2) interleukin 4 (IL-4); interleukin 6 (IL-6); interleukin 8 (IL8); interleukin 10 (IL10); tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), vascular endothelial growth factor (VEGF), monocyte chemotactic protein-1 (MCP-1) epidermal growth factor (EGF), soluble E-selectin, L-selectin, P-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) were determined in both pericardial fluid and serum samples. A total of 45 patients with a mean age of 74 years were included of which 66% were males. Serum levels of all study mediators were within normal limits. Serum and pericardial levels of IL-1 α, IL-1 β, IL-2, IL-4, and IL-10 were similar. Levels of VEGF, EGF, VCAM-2, ICAM 1, E-selectin, P-selectin, and L-selectin were significantly lower in pericardial fluid than in serum. However, levels of IL-6, IL-8, TNF-α, IFN-γ, MCP-1, and MCP-1 were significantly higher in the pericardial fluid than in serum. Under normal conditions, the pattern of distribution of different inflammatory mediators in the pericardial fluid does not reflect serum levels. This may either reflect the condition of the underlying myocardium and epicardial fat or the activity of the mesothelial and mononuclear cells present in pericardial fluid.

Enhanced external counterpulsation ameliorates endothelial dysfunction and elevates exercise tolerance in patients with coronary artery disease

PURPOSE

Enhanced external counterpulsation (EECP) is a new non-drug treatment for coronary artery disease (CAD). However, the long-term effect of EECP on endothelial dysfunction and exercise tolerance, and the relationship between the changes in the endothelial dysfunction and exercise tolerance in the patients with coronary heart disease are still unclear.

METHODS

A total of 240 patients with CAD were randomly divided into EECP group (n = 120) and control group (n = 120). All patients received routine treatment of CAD as the basic therapy. Patients in the EECP group received 35 1-h daily sessions of EECP during 7 consecutive weeks while the control group received the same treatment course, but the cuff inflation pressure was 0-10 mmHg. Peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI), and inner diameter (ID) of the right carotid artery were examined using a Color Doppler Ultrasound and used to calculate the fluid shear stress (FSS). Serum levels of human vascular endothelial cell growth factor (VEGF), vascular endothelial cell growth factor receptor 2 (VEGFR2), and human angiotensin 2 (Ang2) were determined by enzyme-linked immunosorbent assay (ELISA). Exercise load time, maximal oxygen uptake (VO2max ), metabolic equivalent (METs), anaerobic threshold (AT), peak oxygen pulse (VO2max/HR) were assessed using cardiopulmonary exercise tests.

RESULTS

After 1 year follow-up, the EDV, PSV, ID, and FSS were significantly increased in the EECP group (P < 0.05 and 0.01, respectively), whereas there were no significant changes in these parameters in the control group. The serum levels of VEGF and VEGFR2 were elevated in the EECP and control groups (all P < 0.05). However, the changes in VEGF and VEGFR2 were significantly higher in the EECP group than in the control group (P < 0.01). The serum level of Ang2 was decreased in the EECP group (P < 0.05) and no obvious changes in the control group. As for exercise tolerance of patients, there were significant increases in the exercise load time, VO2max, VO2max/HR, AT and METs in the EECP group (all P < 0.05) and VO2max and METs in the control group (all P < 0.05). Correlation analyses showed a significant and positive correlations of VEGF and VEGFR2 levels with the changes in FSS (all P < 0.001). The correlations were still remained even after adjustment for confounders (all Padjustment < 0.001). Linear regression displays the age, the medication of ACEI (angiotensin-converting enzyme inhibitors) or ARB (angiotensin receptor blockers), the diabetes and the changes in VEGF and VEGFR2 were positively and independently associated with the changes in METs after adjustment for confounders (all Padjustment < 0.05).

CONCLUSION

The data of our study suggested that EECP is a useful therapeutic measurement for amelioration of endothelial dysfunction and long-term elevation of exercise tolerance for patients with coronary heart disease.

CLINICAL TRIAL REGISTRATION

[http://www.chictr.org.cn/], identifier [ChiCTR1800020102].

Endostatin in Renal and Cardiovascular Diseases

Endostatin, a protein derived from the cleavage of collagen XVIII by the action of proteases, is an endogenous inhibitor known for its ability to inhibit proliferation and migration of endothelial cells, angiogenesis, and tumor growth. Angiogenesis is defined as the formation of new blood vessels from pre-existing vasculature, which is crucial in many physiological processes, such as embryogenesis, tissue regeneration, and neoplasia.

SUMMARY

Increasing evidence shows that dysregulation of angiogenesis is crucial for the pathogenesis of renal and cardiovascular diseases. Endostatin plays a pivotal role in the regulation of angiogenesis. Recent studies have provided evidence that circulating endostatin increases significantly in patients with kidney and heart failure and may also contribute to disease progression.

KEY MESSAGE

In the current review, we summarize the latest findings on preclinical and clinical studies analyzing the impact of endostatin on renal and cardiovascular diseases.

An overview of human pericardial space and pericardial fluid

The pericardium is a double-layered fibro-serous sac that envelops the majority of the surface of the heart as well as the great vessels. Pericardial fluid is also contained within the pericardial space. Together, the pericardium and pericardial fluid contribute to a homeostatic environment that facilitates normal cardiac function. Different diseases and procedural interventions may disrupt this homeostatic space causing an imbalance in the composition of immune mediators or by mechanical stress. Inflammatory cells, cytokines, and chemokines are present in the pericardial space. How these specific mediators contribute to different diseases is the subject of debate and research. With the advent of highly specialized assays that can identify and quantify various mediators we can potentially establish specific and sensitive biomarkers that can be used to differentiate pathologies, and aid clinicians in improving clinical outcomes for patients.

Different Expressions of Pericardial Fluid MicroRNAs in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy and Ischemic Heart Disease Undergoing Ventricular Tachycardia Ablation

Introduction: Pericardial fluid is enriched with biologically active molecules of cardiovascular origin including microRNAs. Investigation of the disease-specific extracellular microRNAs could shed light on the molecular processes underlying disease development. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart disease characterized by life-threatening arrhythmias and progressive heart failure development. The current data about the association between microRNAs and ARVC development are limited.

Methods and Results: We performed small RNA sequence analysis of microRNAs of pericardial fluid samples obtained during transcutaneous epicardial access for ventricular tachycardia (VT) ablation of six patients with definite ARVC and three post-infarction VT patients. Disease-associated microRNAs of pericardial fluid were identified. Five microRNAs (hsa-miR-1-3p, hsa-miR-21-5p, hsa-miR-122-5p, hsa-miR-206, and hsa-miR-3679-5p) were found to be differentially expressed between patients with ARVC and patients with post-infarction VT. Enrichment analysis of differentially expressed microRNAs revealed their close linkage to cardiac diseases.

Conclusion: Our data extend the knowledge of pericardial fluid microRNA composition and highlight five pericardial fluid microRNAs potentially linked to ARVC pathogenesis. Further studies are required to confirm the use of pericardial fluid RNA sequencing in differential diagnosis of ARVC.

Circulating endostatin as a risk factor for cardiovascular events in patients with stable coronary heart disease: A CLARICOR trial sub-study

BACKGROUND AND AIMS

Raised levels of serum endostatin, a biologically active fragment of collagen XVIII, have been observed in patients with ischemic heart disease but association with incident cardiovascular events in patients with stable coronary heart disease is uncertain.

METHODS

The CLARICOR-trial is a randomized, placebo-controlled trial of stable coronary heart disease patients evaluating 14-day treatment with clarithromycin. The primary outcome was a composite of acute myocardial infarction, unstable angina pectoris, cerebrovascular disease or all-cause mortality. In the present sub-study using 10-year follow-up data, we investigated associations between serum endostatin at entry (randomization) and the composite outcome and its components during follow-up. The placebo group was used as discovery sample (1204 events, n = 1998) and the clarithromycin-treated group as replication sample (1220 events, n = 1979).

RESULTS

In Cox regression models adjusting for cardiovascular risk factors, glomerular filtration rate, and current pharmacological treatment, higher serum endostatin was associated with an increased risk of the composite outcome in the discovery sample (hazard ratio per standard deviation increase 1.11, 95% CI 1.03-1.19, p = 0.004), but slightly weaker and not statistically significant in the replication sample (hazard ratio 1.06, 95% CI 1.00-1.14, p = 0.06). In contrast, strong and consistent associations were found between endostatin and cardiovascular and all-cause mortality in all multivariable models and sub-samples. Addition of endostatin to a model with established cardiovascular risk factors provided no substantial improvement of risk prediction (<1%).

CONCLUSIONS

Raised levels of serum endostatin might be associated with cardiovascular events in patients with stable coronary heart disease. The clinical utility of endostatin measurements remains to be established.

The association between circulating endostatin levels and incident myocardial infarction

OBJECTIVE

Increased levels of circulating endostatin have been observed in patients with prevalent ischemic heart disease. However, the association between circulating endostatin, and incident myocardial infarction (MI) is less studied. Our main aim was to study the association between circulating endostatin and incident MI in the community adjusted for established cardiovascular risk factors in men and women.

DESIGN

Circulating endostatin was measured in a nested case control study based on three large community-based Swedish cohorts, including 533 MI cases, and 1003 age-, sex- and cohort-matched controls. Odds ratios (OR) with 95% confidence intervals (CI) were calculated with adjustments for established cardiovascular risk factors.

RESULTS

Higher endostatin was associated with a higher incidence of MI independently of established cardiovascular risk factors (OR 1.19, 95% CI 1.03-1.37, p = .02), but this association was abolished after additional adjustment for C-reactive protein. Sex-stratified analyses suggest that the association was substantially stronger in women as compared to men.

CONCLUSIONS

In our community based sample, higher endostatin predicted incident myocardial infarction predominantly in women but not independently of CRP. Thus, our findings do not support a broad utility of endostatin measurements for the prediction of incident myocardial infarction in clinical practice.

Vascular endothelial growth factor, endostatin levels and clinical features among patients with ulcerative colitis and irritable bowel syndrome and among healthy controls: a cross-sectional analytical study

BACKGROUND

Increased angiogenetic activity in inflammatory bowel disease (IBD) has been shown in previous studies. The aim of this study was to evaluate the relationship of serum vascular endothelial growth factor (VEGF) and endostatin levels with clinical features and mucosal expression in patients with ulcerative colitis (UC).

DESIGN AND SETTING

Cross-sectional analytical study conducted in a tertiary-level public hospital.

METHODS

Serum VEGF and endostatin levels were determined in 82 individuals: 39 with UC, 28 with irritable bowel syndrome (IBS) and 15 healthy controls (HCs), using enzyme-linked immunosorbent assays (ELISA). VEGF and endostatin expressions were studied using immunohistochemistry (IHC).

RESULTS

Mean serum VEGF and endostatin levels were significantly higher in patients with UC than in patients with IBS and in HCs (511.9 ± 377.5 pg/ml, 305.0 ± 121.42 pg/ml and 36.1 ± 40.6 pg/ml; P = 0.001 for VEGF; and 155.50 ± 59.8 ng/ml, 116.9 ± 23.8 ng/ml and 102.2 ± 22.4 ng/ml; P < 0.001 for endostatin, respectively). There was a positive correlation between serum VEGF and endostatin levels (r = 0.422; P < 0.01). Mean H-scores for VEGF expression were higher in the active UC group than in the inactive UC and IBS groups, in the stroma, endothelium and epithelium. Mean H-scores for endostatin expression were higher in the active UC group than in the inactive UC and IBS groups, in the stroma and endothelium. There was no endostatin expression in the epithelium.

CONCLUSION

Increased endostatin appears to be a defensive reaction to increased VEGF in patients with UC.

New Insights into the Role of Basement Membrane-Derived Matricryptins in the Heart

The extracellular matrix (ECM), which contributes to structural homeostasis as well as to the regulation of cellular function, is enzymatically cleaved by proteases, such as matrix metalloproteinases and cathepsins, in the normal and diseased heart. During the past two decades, matricryptins have been defined as fragments of ECM with a biologically active cryptic site, namely the 'matricryptic site,' and their biological activities have been initially identified and clarified, including anti-angiogenic and anti-tumor effects. Thus, matricryptins are expected to be novel anti-tumor drugs, and thus widely investigated. Although there are a smaller number of studies on the expression and function of matricryptins in fields other than cancer research, some matricryptins have been recently clarified to have biological functions beyond an anti-angiogenic effect in heart. This review particularly focuses on the expression and function of basement membrane-derived matricryptins, including arresten, canstatin, tumstatin, endostatin and endorepellin, during cardiac diseases leading to heart failure such as cardiac hypertrophy and myocardial infarction.

Endostatin: a promising biomarker in the cardiovascular continuum?

The current review article aims to provide an up-to-date summary of previous studies in humans that have reported the association between circulating endostatin levels and different cardiovascular phenotypes. We also aim to provide suggestions for future directions of future research evaluating endostatin as a clinically relevant cardiovascular biomarker. With a few exceptions, higher circulating levels of endostatin seem to reflect vascular and myocardial damage, and a worsened prognosis for cardiovascular events or mortality in individuals with hypertension, diabetes, kidney disease, cardiovascular disease, as well as in the general population. Circulating endostatin seems to be a promising biomarker for cardiovascular pathology, but there is not enough evidence to date to support the use of endostatin measurements in clinical practice.

Lowering homocysteine decreases levels and expression of VEGF(165) and endostatin

BACKGROUND

Homocysteine, vascular endothelial growth factor (VEGF), and endostatin have been implicated in angiogenesis and in the development and progression of atherothrombotic vascular disease. We sought to determine whether homocysteine modulates plasma levels of VEGF and endostatin and their expression in leukocytes in patients with peripheral arterial disease (PAD) or diabetes mellitus (DM).

MATERIALS AND METHODS

Ten patients with PAD and 15 patients with type 2 DM were evaluated before and 6 wk after oral administration of folic acid and B vitamins. Evaluation included measurements of plasma levels of homocysteine, VEGF, and endostatin by enzyme-linked immunosorbent assay and the expression of VEGF and endostatin mRNAs in leukocytes using RT-PCR. The measurements were compared with baseline findings in 12 healthy subjects.

RESULTS

Basal homocysteine (P < 0.001) and VEGF (P < 0.01) levels were elevated in all patients versus healthy subjects. Basal endostatin levels were lower in patients with PAD but were higher in patients with DM compared with healthy subjects (P < 0.001). In patients with PAD or DM, folic acid and B vitamins administration resulted in significant reduction (P < 0.001) of plasma levels of homocysteine (20.9% and 26.2%), VEGF (29.7% and 40.4%) and endostatin (9.4% and 5.7%), respectively. Moreover, VEGF and endostatin mRNA expression in leukocytes was down-regulated in all patients after B vitamins and folate treatment.

CONCLUSION

These findings demonstrate that lowering of homocysteine with B vitamins and folic acid resulted in substantial reduction of plasma levels of VEGF but minimal reduction of endostatin and in down-regulation of their expression in leukocytes in patients with PAD or DM.