Endocan and the respiratory system: a review

Diagnostic Role of Circulating Endocan Levels in Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis

Endocan, as an endothelial cell damage marker, plays role in several cardiovascular and non-cardiovascular diseases. This systematic review and meta-analysis evaluates the role of endocan as a potential diagnostic or prognostic biomarker for obstructive sleep apnea (OSA). International databases including PubMed, Embase, Web of Science, and Scopus were searched for relevant studies assessing endocan levels in OSA patients compared with healthy controls or within different severities or comorbidities of OSA. Random-effect meta-analysis was performed in order to calculate the standardized mean difference (SMD) and 95% confidence interval (CI) of serum/plasma endocan in all comparisons. A total of 10 studies were included in our systematic review, among which seven were used in meta-analysis. Meta-analysis showed that endocan levels were significantly higher in patients with OSA compared with healthy controls (SMD 1.29, 95% CI 0.64-1.93, P < .001) and this was not different between serum and plasma subgroups. However, there was no statistical difference between severe and non-severe OSA patients (SMD .64, 95% CI -.22 to 1.50, P = .147). Considerably, higher endocan levels in patients with OSA in comparison with non-OSA individuals might have clinical implications. This association warrants further research due to its potential use as a diagnostic and prognostic biomarker.

Effect of nano-curcumin supplementation on angina status, and traditional and novel cardiovascular risk factors in overweight or obese patients with coronary slow flow phenomenon: a randomized double-blind placebo-controlled clinical trial

BACKGROUND

Cardiovascular events and poor quality of life are frequently observed in patients with coronary slow flow phenomenon (CSFP). This trial evaluated the effect of nano-curcumin supplement containing curcuminoids, as multifunctional nutraceuticals, on angina status, and some traditional and novel cardiovascular risk factors in overweight or obese patients with CSFP.

METHODS

In this double-blind, randomized, placebo-controlled clinical trial, 42 overweight or obese patients with CSFP received either 80 mg/day of nano-curcumin or placebo for 12 weeks. Seattle angina questionnaire (SAQ) as a clinical measure of angina status, circulating endocan, adropin, homocysteine, lipid profile, and the novel scores of visceral adiposity index (VAI) and waist-triglyceride index (WTI) were assessed before and after the intervention. The independent samples t-test, Mann-Whitney test, analysis of covariance, Chi-square, and Fisher's exact tests were used where appropriate.

RESULTS

All domains of SAQ including physical limitation, angina stability, angina frequency-severity, treatment satisfaction, and disease perception and quality of life improved significantly in the nano-curcumin compared with the placebo group. No significant changes were observed in serum endocan, adropin, and homocysteine following the intervention. Triglycerides, triglyceride/high-density lipoprotein cholesterol ratio, WTI and VAI values improved significantly only within the nano-curcumin group.

CONCLUSIONS

Supplementation with 80 mg/day nano-curcumin (containing curcuminoids) for 12 weeks significantly improved clinically important disease-specific aspects of health in patients with CSFP. Some traditional and novel cardiovascular risk factors improved significantly only compared with the baseline values, which need further investigation.

TRIAL REGISTRATION

This study was approved by the Ethics Committee of Tehran University of Medical Sciences (IR.TUMS.VCR.REC.1398.794). The study protocol was registered at Iranian Registry of Clinical Trials by IRCT20131125015536N8 registration ID at 19.06.2019.

Systematic Review of Endocan as a Potential Biomarker of COVID-19

Since the start of the coronavirus disease 2019 (COVID-19) pandemic, several biomarkers have been proposed to assess the diagnosis and prognosis of this disease. The present systematic review evaluated endocan (a marker of endothelial cell damage) as a potential diagnostic and prognostic biomarker for COVID-19. PubMed, Scopus, Web of Science, and Embase were searched for studies comparing circulating endocan levels between COVID-19 cases and controls, and/or different severities/complications of COVID-19. Eight studies (686 individuals) were included, from which four reported significantly higher levels of endocan in COVID-19 cases compared with healthy controls. More severe disease was also associated with higher endocan levels in some of the studies. Studies reported higher endocan levels in patients who died from COVID-19, were admitted to an intensive care unit, and had COVID-19-related complications. Endocan also acted as a diagnostic and prognostic biomarker with different cut-offs. In conclusion, endocan could be a novel diagnostic and prognostic biomarker for COVID-19. Further studies with larger sample sizes are warranted to evaluate this role of endocan.

Novel inflammatory biomarkers in the prognosis of COVID-19

BACKGROUND

The central role of inflammatory progression in the development of Coronavirus disease 2019 (COVID-19), especially in severe cases, is indisputable. However, the role of some novel inflammatory biomarkers in the prognosis of COVID-19 remains controversial.

OBJECTIVE

To assess the effect of some novel inflammatory biomarkers in the occurrence and prognosis of COVID-19.

METHODS

We systematically retrieved the studies related to COVID-19 and the inflammatory biomarkers of interest. The data of each biomarker in different groups were extracted, then were categorized and pooled. The standardized mean difference was chosen as an effect size measure to compare the difference between groups.

RESULTS

A total of 90 studies with 12,059 participants were included in this study. We found higher levels of endocan, PTX3, suPAR, sRAGE, galectin-3, and monocyte distribution width (MDW) in the COVID-19 positive groups compared to the COVID-19 negative groups. No significant differences for suPAR and galectin-3 were detected between the severe group and mild/moderate group of COVID-19. In addition, the deaths usually had higher levels of PTX3, sCD14-ST, suPAR, and MDW at admission compared to the survivors. Furthermore, patients with higher levels of endocan, galectin-3, sCD14-ST, suPAR, and MDW usually developed poorer comprehensive clinical prognoses.

CONCLUSIONS

In summary, this meta-analysis provides the most up-to-date and comprehensive evidence for the role of the mentioned novel inflammatory biomarkers in the prognosis of COVID-19, especially in evaluating death and other poor prognoses, with most biomarkers showing a better discriminatory ability.

The impact of macrophages on endothelial cells is potentiated by cycling hypoxia: Enhanced tumor inflammation and metastasis

Cycling hypoxia (cyH), neo-angiogenesis, and tumor-associated macrophages are key features of the tumor microenvironment. In this study, we demonstrate that cyH potentiates the induction by unpolarized and M1-like macrophages of endothelial inflammatory phenotype and adhesiveness for monocytes and cancer cells. This process triggers a positive feedback loop sustaining tumor inflammation. This work opens the door for innovative therapeutic strategies to treat tumor inflammation and metastasis.

In cancers, the interaction between macrophages and endothelial cells (ECs) regulates tumor inflammation and metastasis. These cells are both affected by cycling hypoxia (cyH), also called intermittent hypoxia, a feature of the tumor microenvironment. cyH is also known to favor tumor inflammation and metastasis. Nonetheless, the potential impact of cyH on the dialog between macrophages and ECs is still unknown. In this work, the effects of unpolarized, M1-like, and M2-like macrophages exposed to normoxia, chronic hypoxia (chH), and cyH on endothelial adhesion molecule expression, pro-inflammatory gene expression, and EC adhesiveness for monocytes and cancer cells were investigated. cyH increased the ability of unpolarized and M1-like macrophages to induce EC inflammation and to increase the expression of the EC endothelial adhesion molecule ICAM1, respectively. Unpolarized, M1-like, and M2-like macrophages were all able to promote EC adhesive properties toward cancer cells. Furthermore, the ability of macrophages (mostly M1-like) to shift EC phenotype toward one allowing cancer cell and monocyte adhesion onto ECs was potentiated by cyH. These effects were specific to cyH because they were not observed with chH. Together, these results show that cyH amplifies the effects of macrophages on ECs, which may promote tumor inflammation and metastasis.

Evaluation of endothelial cell-specific molecule-1 as a biomarker of glycocalyx damage in canine myxomatous mitral valve disease

Background

Endothelial cell-specific molecule-1 (ESM-1) has emerged as a potential biomarker for cardiovascular disease in humans. Myxomatous mitral valve disease (MMVD) is the most common heart disease in dogs, and we hypothesized that MMVD causes chronic inflammation that increases susceptibility to endothelial glycocalyx (eGCX) damage. In this study, we measured the concentration of ESM-1 in a group of dogs with MMVD and evaluated factors affecting eGCX damage.

Results

Sixty-four dogs (control, n = 6; MMVD, n = 58) were enrolled in this study. There was no significant difference in serum ESM-1 concentrations among the MMVD stages. The serum ESM-1 concentration was significantly higher in the death group than in the alive group in MMVD dogs. (p = 0.006). In five dogs with MMVD, serum ESM-1 concentrations tended to decrease when the cardiac drug (pimobendan, furosemide, and digoxin) dose was increased.

Conclusions

In cases where MMVD progressed to decompensated heart failure with clinical symptoms and resulted in death, the concentration of serum ESM-1 increased significantly. Therefore, ESM-1 could be utilized as a new potential negative prognostic factor in patients with MMVD.

Blood and aqueous humor phoenixin, endocan and spexin in patients with diabetes mellitus and cataract with and without diabetic retinopathy

Peptide phoenixin (PNX), endocan (EDC), and spexin (SPX) are associated with diabetes. Therefore, the purpose of this study was to investigate the levels of PNX, EDC and SPX in the blood and aqueous humor (AH) of patient with type 2 diabetes with and without DRP and cataract. 30 type 2 diabetes patients with cataract (DM + C), 30 DRP patient with cataract (DRP + C), 30 non-diabetic patient with only cataract and 30 control participants were enrolled into this study. PNX, EDC, and SPX were measured in blood and AH by ELISA. In patients with DRP + C, the levels of PNX and EDC were significantly higher in both AH and blood samples compared with the group of patients without DRP + C (<0.05). Also, in patients with DM + C, the levels of PNX and EDC were higher in both AH and blood samples compared with the group of patients without DM + C. However, in patients with DRP + C, the levels of SPX were significantly lower in both AH and blood samples compared with the group of patients without DRP + C (<0.05). Also, in patients with DM + C, the levels of SPX were also lower in both AH and blood samples compared with the group of patients without DM + C. These findings suggest that increased PNX, EDC, and decreased SPX amounts in blood and AH of DM + C and DRP + C groups when compared with control and cataract groups show that they might have a role in the pathophysiology of DM + C, especially in the DRP + C.

Endocan in Acute Leukemia: Current Knowledge and Future Perspectives

Endocan is a soluble dermatan sulfate proteoglycan expressed by endothelial cells and detected in serum/plasma. Its expression is increased in tumors/tumor vessels in several human malignancies, and high expression (high serum/plasma levels or tumor levels) has an adverse prognostic impact in several malignancies. The p14 endocan degradation product can also be detected in serum/plasma, but previous clinical studies as well as previously unpublished results presented in this review suggest that endocan and p14 endocan fragment levels reflect different biological characteristics, and the endocan levels seem to reflect the disease heterogeneity in acute leukemia better than the p14 fragment levels. Furthermore, decreased systemic endocan levels in previously immunocompetent sepsis patients are associated with later severe respiratory complications, but it is not known whether this is true also for immunocompromised acute leukemia patients. Finally, endocan is associated with increased early nonrelapse mortality in (acute leukemia) patients receiving allogeneic stem cell transplantation, and this adverse prognostic impact seems to be independent of the adverse impact of excessive fluid overload. Systemic endocan levels may also become important to predict cytokine release syndrome after immunotherapy/haploidentical transplantation, and in the long-term follow-up of acute leukemia survivors with regard to cardiovascular risk. Therapeutic targeting of endocan is now possible, and the possible role of endocan in acute leukemia should be further investigated to clarify whether the therapeutic strategy should also be considered.

Prognostic and Diagnostic Value of Endocan in Kidney Diseases

Endocan, previously called endothelial cell-specific molecule-1, is a soluble proteoglycan that is predominantly expressed in vascular endothelial cells of the lungs and kidneys. It is upregulated by proinflammatory cytokines and plays a critical role in inflammatory, proliferative, and neovascularization processes. The utility of endocan as a biomarker in a wide spectrum of diseases is being increasingly acknowledged. In this review, we summarize the current evidence concerning the role of endocan in kidney diseases, with emphasis on its prognostic and diagnostic value. It seems that the determination of plasma endocan levels may provide useful prognostic information in many types of renal failure such as chronic kidney disease, IgA nephropathy, and diabetic nephropathy. Endocan could additionally improve the early diagnostic evaluation of acute kidney disease, chronic renal allograft injury, and acute rejection after kidney transplantation, thus contributing to endothelial cell injury monitoring in a timely manner.

Is Serum Endocan Level an Indicator of the Severity of Childhood Community-Acquired Pneumonia?

Objective We aimed to investigate the relationship between serum endocan, procalcitonin (PCT), C-reactive protein (CRP), white blood cell count (WBC), neutrophil/lymphocyte ratios (NLR), and the severity of the disease in childhood community-acquired pneumonia (CAP) cases.

Methods This cross-sectional designed study included 30 pneumonia cases and 30 severe pneumonia cases aged between 3 months and 18 years who were hospitalized and treated in our hospital with the diagnosis of CAP. We also included 30 healthy controls in the same age range. Pearson's correlation and receiver operating characteristic (ROC) curve analyzes were performed.

Results PCT, endocan, NLR, and CRP levels were found to be significantly higher in patients with severe pneumonia. Sensitivity and specificity values in detecting pneumonia were 72.5 and 93% for PCT, 78.4 and 83.3% for CRP, 78.4 and 76.7% for endocan, and 64.7 and 63.3% for NLR. However, the area under the curve in ROC analysis were 0.821, 0.840, 0.842, and 0.670 for PCT, CRP, endocan, and NLR respectively.

Conclusion Endocan may be a marker of the diagnosis of pneumonia and not clinical severity, but studies are needed in large patient populations.

Endocan: A Key Player of Cardiovascular Disease

Endothelial dysfunction is considered to be an early change in atherosclerosis. Endocan, also known as endothelial cell specific molecule-1, is a soluble proteoglycan mainly secreted by endothelial cells. Inflammatory factors such as IL-1β and TNF-α can up regulate the expression of endocan and then affect the expression of cell adhesion molecules, such as ICAM-1 and VCAM-1, which play an important role in promoting leukocyte migration and inflammatory response. Elevated plasma levels of endocan may reflect endothelial activation and dysfunction, and is considered to be a potential immuno-inflammatory marker that may be related to cardiovascular disease. In the case of hypertension, diabetes, angina pectoris and acute myocardial infarction, the increase or decrease of serum endocan levels is of great significance. Here, we reviewed the current research on endocan, and emphasis its possible clinical value as a prognostic marker of cardiovascular disease. Endocan may be a useful biomarker for the prognosis of cardiovascular disease, but more research is needed on its mechanism of action.

Proteoglycan Endocan: A multifaceted therapeutic target in Cancer

Endocan is known to be a circulating dermatan sulfate proteoglycan that regulates endothelial cell function. Dysregulation of endocan expression is observed not only in the tumor vasculature but also in cancer cells. Accumulating evidence has revealed that disordered endocan facilitates cancer progression via enhancing cancer cell proliferation, cell mobility, and cancer stemness properties. Recently, various interacting proteins and diverse subcellular localizations of endocan were identified in cancer cells. Herein, we summarize the application of endocan in cancer diagnoses and prognoses using serum and tumor specimens. We further discuss that the aberrant molecular characteristics of endocan may be due to the mislocalization of endocan in cancer cells. Defining the specific cellular roles of endocan will provide a promising diagnostic factor and therapeutic target for cancer patients.

Inhalation of particulate matter containing free radicals leads to decreased vascular responsiveness associated with an altered pulmonary function

Airborne particulate matter (PM) is associated with an increased risk for cardiovascular diseases. Although the goal of thermal remediation is to eliminate organic wastes through combustion, when incomplete combustion occurs, organics chemisorb to transition metals to generate PM-containing environmentally persistent free radicals (EPFRs). Similar EPFR species have been detected in PM found in diesel and gasoline exhaust, woodsmoke, and urban air. Prior in vivo studies demonstrated that EPFRs reduce cardiac function secondary to elevations in pulmonary arterial pressures. In vitro studies showed that EPFRs increase ROS and cytokines in pulmonary epithelial cells. We thus hypothesized that EPFR inhalation would promote lung inflammation and oxidative stress, leading to systemic inflammation, vascular endothelial injury, and a decline in vascular function. Mice were exposed to EPFRs for either 4 h or for 4 h/day for 10 days and lung and vascular function were assessed. After a 4-h exposure, plasma nitric oxide (NO) was reduced while endothelin-1 (ET-1) was increased, however lung function was not altered. After 10 day, plasma NO and ET-1 levels were again altered and lung tidal volume was reduced. These time course studies suggested the vasculature may be an early target of injury. To test this hypothesis, an intermediate time point of 3 days was selected. Though the mice exhibited no marked inflammation in either the lung or the blood, we did note significantly reduced endothelial function concurrent with a reduction in lung tidal volume and an elevation in annexin V protein levels in the lung. Although vascular dysfunction was not dependent upon inflammation, it may be associated with an injury at the air-blood interface. Gene expression analysis suggested roles for oxidative stress and aryl hydrocarbon receptor (Ahr) signaling. Studies probing the relationship between pulmonary oxidative stress and AhR signaling at the air-blood interface with vascular dysfunction seem warranted.NEW & NOTEWORTHY Particulate matter (PM) resulting from the combustion of organic matter is known to contribute to cardiopulmonary disease. Despite hypotheses that cardiovascular dysfunction occurring after PM exposures is secondary to lung or systemic inflammation, these studies investigating exposures to PM-containing environmentally persistent free radicals (EPFRs) demonstrate that cardiovascular dysfunction precedes pulmonary inflammation. The cardiopulmonary health consequences of EPFRs have yet to be thoroughly evaluated, especially in healthy, adult mice. Our data suggest the vasculature as a direct target of PM exposure, and our studies aimed to elucidate the mechanisms contributing to EPFR-induced vascular dysfunction.

Endocan and Circulating Progenitor Cells in Women with Systemic Sclerosis: Association with Inflammation and Pulmonary Hypertension

Background: Systemic sclerosis (SSc) is characterized by early vasculopathy and fibrosis in the skin, lungs, and other tissues. Vascular manifestations of SSc include Raynaud’s phenomenon, digital ulcers, and pulmonary artery hypertension (PAH). PAH is the second most common cause of mortality in SSc. Circulating CD34+ cells associated with cardiovascular health status in several conditions, including chronic immune-inflammatory disease. CD34+ cell numbers have been found inconstantly reduced in SSc. Endocan, a proteoglycan expressed by endothelial cells, was recently suggested as a marker of vascular stress. We tested the relationships among CD34+ cells, endocan, inflammatory markers, vitamin D levels, and clinical parameters in SSc patients with PAH. METHODS: Standard echocardiography was performed. Vitamin D levels, CD34+ cells, inflammatory markers, endocan plasma levels were determined in 36 female SSc patients (24 diffuse/12 limited) and 36 matched controls (HC). RESULTS: We found no difference in CD34+ and vitamin D levels in SSc as compared to controls; ESR, CRP, fibrinogen, endocan, sPAP were higher in SSc with respect to controls. We found a correlation between endocan and: CD34+ cells (r: −0.540, p = 0.002), pulmonary arterial pressure (sPAP) (r: 0.565, p < 0.001), tricuspid annular plane excursion (TAPSE) (r: −0.311, p < 0.01), and E/A ratio (r: −0.487, p < 0.001), but not with ejection fraction (r: −0.057, p = 0.785) in SSc. CD34+ cells correlate with fibrinogen (r: −0.619, p < 0.001), sPAP (r: −0.404, p = 0.011), E/A (r: 0.470, p < 0.005 in SSc. CONCLUSION: CD34+ cell number was significantly correlated with endocan levels and with sPAP in SSc; endocan and CD34+ progenitor cells might be suggested as a potential marker of disease status.

Endocan as a potential biomarker of disease severity and exacerbations in COPD

INTRODUCTION

Endocan is a proteoglycan that is regarded as a novel marker of endothelial dysfunction. Endothelial dysfunction in pulmonary vascular bed is known to play an important role for the pathogenesis of COPD.

OBJECTIVE

This study aimed to determine serum endocan levels in patients with stable COPD and acute exacerbation of COPD (AECOPD) and to test the relationship between serum endocan levels and exacerbations.

METHODS

This study enrolled a total of 55 COPD patients, 24 of which had AECOPD and 31 had stable COPD. All patients' basic demographic and clinical data were recorded and blood samples were collected.

RESULTS

Serum endocan levels were significantly higher in the AECOPD group compared to the stable COPD and control groups (for both p < 0.001) and stable COPD group had higher levels than the control group (p < 0.005). Additionally, serum endocan levels were negatively correlated with FVC, FEV1, partial oxygen pressure and oxygen saturation (r = -0.30, p = 0.03; r = -0.34, p = 0.01; r = -0.34, p = 0.01 and r = -0.36, p = 0.007 respectively), and positively correlated with disease duration and systolic pulmonary artery pressure (r = 0.47, p < 0.001; r = 0.31, p = 0.02 respectively). A cut-off value of 434.29 pg/ml for endocan predicted exacerbation with a sensitivity of 79% and a specificity of 84% (AUC: 0.778, 95% Cl 0.648-0.909; p < 0.001). Logistic regression analysis revealed that increased endocan levels was independent predictor of COPD exacerbation (OR = 9.32, 95%CI, 1.64-52.95; p = 0.01).

CONCLUSION

Endocan may be a novel biomarker for detection of endothelial dysfunction and prediction of exacerbations in patients with COPD.

The role of endocan and selected pro-inflammatory cytokines in systemic lupus erythematosus

INTRODUCTION

Systemic lupus erythematosus (SLE) is a multisystem inflammatory autoimmune disease with a wide spectrum of clinical manifestations. Cytokines such as interleukin-1 (IL-1) and tumour necrosis factor α (TNF-α) are involved in its pathogenesis. Endocan is a novel marker of endothelial dysfunction and is likely to be engaged in proinflammatory processes in SLE.

AIM

To determine whether endocan serum concentration in SLE patients vary from healthy controls.

MATERIAL AND METHODS

The study included 36 patients with SLE. SLEDAI-2K score was used to assess disease activity. The control group comprised 23 healthy volunteers. ELISA kits were used to assess serum concentrations of endocan, IL-1β, TNF-α, vascular endothelial growth factor (VEGF) and high-sensitivity C reactive protein (hs-CRP).

RESULTS

The serum concentration of endocan was significantly higher (p < 0.001) in the SLE group than in healthy individuals. A positive correlation was found between serum levels of endocan and IL-1β (r = 0.47, p < 0.05). Active SLE patients (SLEDAI-2K score above 6 points) with an elevated total cholesterol level (above 5.17 mmol/l) were found to have VEGF concentration higher than those with a normal cholesterol level (p < 0.03). No other relevant relationships were found between the serum concentration of endocan, other laboratory parameters, anthropometric features, activity and duration of SLE.

CONCLUSIONS

A higher serum level of endocan in SLE patients indicates its possible role in the pathogenesis of the disease and reflects endothelial dysfunction. Our findings indicate that endocan could serve as a potential marker of endothelial dysfunction in SLE.

Peripheral arterial tonometry as a method of measuring reactive hyperaemia correlates with organ dysfunction and prognosis in the critically ill patient: a prospective observational study

Predictions of mortality may help in the selection of patients who benefit from intensive care. Endothelial dysfunction is partially responsible for many of the organic dysfunctions in critical illness. Reactive hyperaemia is a vascular response of the endothelium that can be measured by peripheral arterial tonometry (RH-PAT). We aimed to assess if reactive hyperaemia is affected by critical illness and if it correlates with outcomes. Prospective study with a cohort of consecutive patients admitted to an Intensive Care Unit. RH-PAT was accessed on admission and on the 7th day after admission. Early and late survivors were compared to non-survivors. The effect of RH-PAT variation on late mortality was studied by a logistic regression model. The association between RH-PAT and severity scores and biomarkers of organic dysfunction was investigated by multivariate analysis. 86 patients were enrolled. Mean ln(RHI) on admission was 0.580 and was significantly lower in patients with higher severity scores (p < 0.01) and early non-survivors (0.388; p = 0.027). The model for prediction of early-mortality estimated that each 0.1 decrease in ln(RHI) increased the odds for mortality by 13%. In 39 patients, a 2nd RH-PAT measurement was performed on the 7th day. The variation of ln(RHI) was significantly different between non-survivors and survivors (− 24.2% vs. 63.9%, p = 0.026). Ln(RHI) was significantly lower in patients with renal and cardiovascular dysfunction (p < 0.01). RH-PAT is correlated with disease severity and seems to be an independent marker of early mortality, cardiovascular and renal dysfunctions. RH-PAT variation predicts late mortality. There appears to be an RH-PAT impairment in the acute phase of severe diseases that may be reversible and associated with better outcomes.

Endocan: A novel biomarker for risk stratification, prognosis and therapeutic monitoring in human cardiovascular and renal diseases

The vascular endothelium is localized at the interface between the blood and surrounding tissues, playing a pivotal role in the maintenance of tissue-fluid homeostasis and in the regulation of host defense, inflammation, vascular tone and remodeling, angiogenesis and haemostasis. The dysfunctional endothelium was shown to be implicated in the pathophysiology of several endothelial-dependent disorders, such as arterial hypertension, coronary artery disease, heart failure and chronic kidney disease, in which it is an early predictor of cardiovascular events. Endocan is a soluble dermatan sulphate proteoglycan mainly secreted by the activated endothelium. It is upregulated by several proinflammatory cytokines and proangiogenic factors and may itself contribute to the inflammatory status. In addition of being a surrogate marker of inflammation and endothelial dysfunction, it seems to be involved in the regulation of several proliferative and neovascularization processes. Therefore, its utility as a biomarker in a wide spectrum of diseases has been increasingly explored. Here, we review the current evidence concerning the role of endocan in several human cardiovascular and renal diseases, where it seems to be a promising biomarker for risk stratification, prognosis and therapeutic monitoring.

Identification of novel functions of the ROCK2-specific inhibitor KD025 by bioinformatics analysis

Rho-associated protein kinases (ROCKs) have various cellular functions, which include actin cytoskeleton remodeling and vesicular trafficking, and there are two major mammalian ROCK isotypes, namely, ROCK1 (ROKβ) and ROCK2 (ROKα). The ROCK2-specific inhibitor KD025 (SLx-2119) is currently undergoing phase II clinical trials, but its cellular functions have not been fully explored. In this study, we investigated the functions of KD025 at the genomics level by bioinformatics analysis using the GSE8686 microarray dataset from the NCBI GEO database, in three different primary human cell lines. An initial microarray analysis conducted by Boerma et al. focused on the effects of KD025 on cell adhesion and blood coagulation, but did not provide comprehensive information on the functions of KD025. Our analysis of differentially expressed genes (DEGs) showed ~70% coincidence with Boerma et al.'s findings, and newly identified that CCND1, CXCL2, NT5E, and SMOX were differentially expressed by KD025. However, due to low numbers of co-regulated DEGs, we were unable to extract the functions of KD025 with significance. To overcome this limitation, we used gene set enrichment analysis (GSEA) and the heatmap hierarchical clustering method. We confirmed KD025 regulated inflammation and adipogenesis pathways, as previously reported experimentally. In addition, we found KD025 has novel regulatory functions on various pathways, including oxidative phosphorylation, WNT signaling, angiogenesis, and KRAS signaling. Further studies are required to systematically characterize these newly identified functions of KD025.

Endocan as a marker of disease severity in pulmonary thromboembolism

INTRODUCTION

The aim of this study is to determine the serum endocan levels in patients with pulmonary thromboembolism (PTE) and investigate whether a relationship exists between serum endocan levels and the disease severity.

MATERIALS AND METHODS

The study included 85 patients with acute PTE and 40 healthy control subjects. The patients with PTE were divided into three groups at admission as "high-risk", "intermediate-risk" and "low-risk", considering the guidelines of the European Society of Cardiology. Serum endocan levels in all participants' blood samples were measured.

RESULTS

The mean serum endocan levels were significantly higher in the PTE group, compared to the control subjects (P < 0.001). Serum endocan levels were significantly higher in the "high-risk" group when compared with patients in the "low-risk" and "intermediate-risk" groups (P < 0.001 and P < 0.01 respectively). Similarly, serum endocan levels were higher in the "intermediate-risk" group compared to those in the "low-risk" group (P < 0.001). There was a negative correlation between serum endocan levels and partial oxygen pressure (r = -0.262, P = 0.016), whereas a positive correlation was found between the serum endocan levels and systolic pulmonary arterial pressure (r = 0.296, P = 0.006). Additionally, endocan had an area under the curve in the receiver operating characteristic curve of 0.837 (0.768-0.907; 95% CI; P < 0.001) and cut-off value was 194.5 pg/mL (sensitivity 80%, specificity 72.5%).

CONCLUSION

Serum endocan levels were higher and related to the severity of the disease in PTE patients. Additionally, endocan could be an indicator to be used in the diagnosis of PTE and in the prediction of the disease severity.

Identification of ESM1 overexpressed in head and neck squamous cell carcinoma

Background

Endocan, also known as endothelial cell specific molecule-1 (ESM1), is a 50 kDa soluble proteoglycan which is frequently overexpressed in many cancer types. Whether it is dysregulated in head and neck squamous cell carcinoma (HNSCC) has not been investigated.

Methods

We analyzed the expression of ESM1 using bioinformatics analysis based on data from The Cancer Genome Atlas (TCGA), and then validated that ESM1 was significantly overexpressed in human HNSCC at the protein level using immunohistochemistry. We also analyzed the genes co-expressed with ESM1 in HNSCC.

Results

The most correlated gene was angiopoietin-2 (ANGPT2), a molecule which regulates physiological and pathological angiogenesis. Several transcription factor binding motifs including SMAD3, SMAD4, SOX3, SOX4, HIF2A and AP-1 components were significantly enriched in the promoter regions of the genes co-expressed with ESM1. Further analysis based on ChIP-seq data from the ENCODE (Encyclopedia of DNA Elements) project revealed that AP-1 is an important regulator of ESM1 expression.

Conclusions

Our results revealed a dysregulation of ESM1 and a potential regulatory mechanism for the co-expression network in HNSCC.

Endocan Is an Independent Predictor of Heart Failure-Related Mortality and Hospitalizations in Patients with Chronic Stable Heart Failure

Background

Heart failure (HF) is characterized by unfavorable prognosis. Disease trajectory of HF, however, may vary, and risk assessment of patients remains elusive. In our study, we sought to determine the prognostic impact of endocan—a novel biomarker of endothelial dysfunction and low-grade inflammation—in patients with heart failure.

Methods

In outpatients with chronic HF, baseline values of endocan were determined and clinical follow-up for a minimum of 18 months obtained. A multivariate Cox proportional hazard model was built for HF-related death or hospitalization requiring inotropic support.

Results

A total of 120 patients (mean age 71 years, 64% male, mean LVEF 36%) were included. During a mean follow-up of 656 ± 109 days, 50 patients (41.6%) experienced an event. On Cox multivariate analysis, endocan values emerged as an independent predictor of HF prognosis (HR, 1.471 CI 95% 1.183-1.829, p = 0.001, for each 1 ng/mL increase) even after adjustment for age, gender, HF etiology, LVEF, NYHA class, NT-proBNP, and exercise tolerance.

Conclusions

Endocan is an independent predictor of HF-related events in chronic HF individuals and represents a promising tool for risk assessment of HF patients.

Is Endocan a Novel Diagnostic Marker for the Severity of Bronchopulmonary Dysplasia in Very Low Birth Weight Infants?

INTRODUCTION

Endocan levels were found to be associated with severity and mortality of the respiratory system diseases.

OBJECTIVE

We aimed to figure out whether endocan was an important marker for the diagnosis, severity and follow-up of bronchopulmonary dysplasia (BPD).

MATERIALS AND METHODS

Infants with moderate/severe BPD, and who required hydrocortisone treatment were included in the study group. Infants without BPD were allocated in the control group. Endocan levels were compared between the control group and the study group, and before and after the treatment in the study group.

RESULTS

A total of 148 infants, 74 infants in the control group and 74 infants in the BPD group, were included. The endocan level was higher in the BPD group than in the control group (P = .001). Endocan levels before treatment in the BPD group was found to be higher than endocan level after treatment (P = .021).

CONCLUSION

Our study found that endocan levels increased in moderate/severe BPD. Serum endocan levels may be a safe and novel indicator for the follow-up of response to treatment and the prognosis of the severity of the disease.

Enhanced Function of Induced Pluripotent Stem Cell-Derived Endothelial Cells Through ESM1 Signaling

The mortality rate for (cardio)‐vascular disease is one of the highest in the world, so a healthy functional endothelium is of outmost importance against vascular disease. In this study, human induced pluripotent stem (iPS) cells were reprogrammed from 1 ml blood of healthy donors and subsequently differentiated into endothelial cells (iPS‐ECs) with typical EC characteristics. This research combined iPS cell technologies and next‐generation sequencing to acquire an insight into the transcriptional regulation of iPS‐ECs. We identified endothelial cell‐specific molecule 1 (ESM1) as one of the highest expressed genes during EC differentiation, playing a key role in EC enrichment and function by regulating connexin 40 (CX40) and eNOS. Importantly, ESM1 enhanced the iPS‐ECs potential to improve angiogenesis and neovascularisation in in vivo models of angiogenesis and hind limb ischemia. These findings demonstrated for the first time that enriched functional ECs are derived through cell reprogramming and ESM1 signaling, opening the horizon for drug screening and cell‐based therapies for vascular diseases. Therefore, this study showcases a new approach for enriching and enhancing the function of induced pluripotent stem (iPS) cell‐derived ECs from a very small amount of blood through ESM1 signaling, which greatly enhances their functionality and increases their therapeutic potential. Stem Cells2019;37:226–239

The association of elevated circulating endocan levels with lung function decline in COPD patients

Background

Endocan is thought to be a novel inflammatory marker that is associated with a variety of inflammatory diseases. However, its role in the pathogenesis of COPD remains unclear. This study aims to explore the potential role of endocan in COPD.

Methods

In total, 27 healthy volunteers, 55 COPD patients and 36 acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients were included in the study. Basic demographic characteristics, clinical features and blood samples were collected. Magnetic luminex screening assays were used to detect the concentration of endocan, Fas and Fas ligand (Fas-L) in plasma. Differences between groups were compared using an Independent sample t-test, Welch’s t-test, chi-squared test and Wilcoxon rank sum test. The correlations of plasma endocan with lung function parameters, Fas and Fas-L were analyzed by Pearson’s partial correlation test (adjusted for age, gender, body mass index and smoking history) and multiple linear regression.

Results

Plasma endocan levels in COPD patients were significantly higher than those in healthy volunteers (509.7±18.25 pg/mL vs 434.8±18.98 pg/mL (P=0.0124)), and AECOPD patients had the highest levels of endocan (524.7±27.18 pg/mL). Correlation analysis showed that circulating endocan had a negative correlation to FEV₁/FVC, FEV₁/predictive and FVC (adjusted r=−0.213, P=0.03; adjusted r=−0.209, P=0.034; and adjusted r=−0.300, P=0.002, respectively), and had a positive correlation to Fas (adjusted r=0.280, P=0.004).

Conclusion

Our study shows that elevated circulating endocan levels are associated with reduced lung ventilation function in COPD and AECOPD patients. In addition, endocan may influence apoptosis in COPD, suggesting that endocan may play a role in COPD pathogenesis.

Serum endocan levels in patients with stable COPD

Background

Endothelial cell specific molecule-1, also called as endocan, is a dermatan sulfate proteoglycan, which is expressed by endothelial cells in alveolar walls of the lung and kidney. High endocan levels are found associated with endothelial dysfunction and inflammation. We hypothesize that endocan level is also high in COPD due to systemic inflammation and endothelial dysfunction. We aimed to investigate the expression of endocan in patients with stable COPD.

Material and methods

The study included patients with COPD and control subjects. COPD patients were classified according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 criteria. Demographics, body mass index, smoking history, and comorbidities were recorded. Endocan levels of COPD patients and controls were compared.

Results

Totally, 88 subjects (47 stable COPD patients, 41 controls) were evaluated. Endocan levels were significantly higher in COPD patients than control group (860.1±259.8 vs 647.3±316.9 pg/mL, P=0.001). There was no relationship between GOLD COPD categories and endocan levels. Also endocan levels were similar between COPD patients with or without hypoxemia.

Conclusion

Serum endocan level was significantly higher in patients with stable COPD. Further studies should be performed to better understand the relationship between endocan and COPD.

A novel role of endocan in alleviating LPS-induced acute lung injury

AIMS

Endotoxin induced acute lung injury (ALI) is a critical complication of some clinical illnesses. Endothelial cell dysfunction and excessive pro-inflammation cytokine release are pivotal to the injury of alveolar-capillary membrane which is the typical characteristic of endotoxic lung injury. As a potential marker of endothelial cells, endocan plays an important role in many endothelial-dependent pathophysiological diseases. We speculated that endocan have anti-inflammatory property in ALI. Here, we investigated the role of endocan in LPS-induced ALI.

MATERIALS AND METHODS

Mice were randomly divided into 4 groups. LPS were used to construct ALI mice model by aerosolization for 20 min. Endocan was intraperitoneal injected at 30 min before LPS exposure. Levels of TNF-α, IFN-γ, IL-1β, IL-6 and MPO activities were detected by indicated ELISA. Cell apoptotic rate was determined by Annexin V/PI kit, ROS level and MPTP were detected by DCFH-DA and JC-1 kit, respectively. Seahorse XF96 was applied to evaluate the alteration of OCR and ECAR. Western blot and qRT-PCR were used to detect indicated molecules.

KEY FINDINGS

Endocan effectively decreased TNF-α, IFN-γ, IL-1β, and IL-6 levels as well as relieved pulmonary epithelium cell apoptosis caused by LPS exposure. Endocan significantly reversed LPS induced UPR^mt and promoted cell metabolism reprogramming which were crucial for the protective characteristic of endocan in ALI mice model.

SIGNIFICANCE

The above findings suggested endocan could significantly suppress inflammatory response in ALI model through attenuating UPR^mt associated apoptosis and switch cellular bioenergetics, indicating endocan could be considered as a promising compound against LPS induced ALI.