Endocan Levels Research Articles

Serum Proteoglycans as Prognostic Biomarkers of Hepatocellular Carcinoma in Patients with Alcoholic Cirrhosis

Proteoglycans are involved in neoangiogenesis and transduction of oncogenic signals, two hallmarks of carcinogenesis. This study sought to assess the prognostic value of serum levels of three proteoglycans (endocan, syndecan-1, and glypican-3) and VEGF in 295 patients with alcoholic cirrhosis: 170 without hepatocellular carcinoma, 58 with early hepatocellular carcinoma, and 67 with advanced hepatocellular carcinoma at inclusion. We analyzed the association between proteoglycan levels and prognosis using Kaplan-Meier and Cox methods. Serum levels of the three proteoglycans and VEGF were increased in patients with advanced hepatocellular carcinoma compared with those without hepatocellular carcinoma or with early hepatocellular carcinoma. In multivariate analysis, high levels of serum endocan (>5 ng/mL) were independently associated with death [HR, 2.84; 95% confidence interval (CI,) 1.18-6.84; P = 0.02], but not with hepatocellular carcinoma occurrence, in patients without hepatocellular carcinoma at baseline. High serum endocan (>5 ng/mL) and syndecan-1 (>50 ng/mL) levels were significantly associated with greater risk of tumor recurrence (P = 0.025) in patients with early hepatocellular carcinoma treated by radiofrequency ablation. In patients with advanced hepatocellular carcinoma, high serum levels of endocan (P = 0.004) and syndecan-1 (P = 0.006) were significantly associated with less favorable overall survival. However, only a high level of serum syndecan-1 (>50 ng/mL) was independently associated with greater risk of death (HR, 6.21 95% CI, 1.90-20.30; P = 0.0025). Serum endocan and syndecan-1 are easily assessable prognostic serum biomarkers of overall survival in alcoholic cirrhosis with and without hepatocellular carcinoma. These new biomarkers will be useful to manage patients with hepatocellular carcinoma developed on alcoholic cirrhosis.

Identification of a 14 kDa endocan fragment generated by cathepsin G, a novel circulating biomarker in patients with sepsis

Severe septic syndrome, which is the most prevalent and lethal cause of acute respiratory distress syndrome, remains one of the most frequent causes of admission and death in intensive care units (ICU). Inflammatory phenomenon leading to severe sepsis are multiple and not yet completely understood. The main target damage during severe sepsis is the endothelium. Endocan, specifically secreted by activated-pulmonary vascular endothelial cells, is thought to play a key role in the control of the lung inflammatory reaction. A recent clinical investigation found that a low plasma endocan level was predictive of respiratory failure. In this study, the hypothesis that low levels of endocan may result from proteolysis was tested. We demonstrate that cathepsin G (CG), neutrophil elastase (NE), and to a lesser extent proteinase 3 (PR3), degrade endocan. Interestingly, a novel endocan peptide fragment of 14kDa, named p14, was identified, resulting from the specific cleavage of endocan by CG, corresponding to the N-terminal 111–116 amino acids of the endocan polypeptide. An immunoassay specific for p14 endocan fragment was then developed, and revealed increased plasma levels of p14 in 20 out of 55 severe septic patients, ranging from 0.52 to 10.40ng/mL versus undetectable p14 in plasma from 32 control subjects (p=0.0011). No correlations were found between p14 and endocan blood levels in severe septic patients. Taken together, the p14 endocan fragment represents a novel interesting biomarker which could participate to the pathogenesis of sepsis.

Serum levels of endothelium-derived endocan are increased inpatients with untreated acute myeloid leukemia

Endocan is a soluble proteoglycan expressed only by vascular endotheliumand is also found circulating in the bloodstream. Inflammatory cytokines aswell as proangiogenic growth factors increase its expression, and increasedserum levels are found in immunocompetent patients with sepsis. We investigatedserum endocan levels in patients with untreated acute myeloid leukemia (AML)and AML patients during chemotherapy-induced bone marrow failure. We observedincreased levels in 40 AML patients compared with healthy controls, whichwas also confirmed in a second cohort. The serum levels decreased after intensivechemotherapy and subsequent severe chemotherapy-induced cytopenia, and increasedlevels were thereafter observed during bone marrow regeneration. However,even for these severely immunocompromized patients, serum endocan levels increasedduring complicating bacterial infections before a decrease was seen duringantibiotic therapy. To conclude, serum endocan is a disease marker in AML,but serum levels are also affected by complicating infections and bone marrowregeneration.

Lower serum endocan levels are associated with the development of acute lung injury after major trauma

PurposeEndocan is a proteoglycan expressed by endothelial cells in the lung that may inhibit leukocyte recruitment and thus prevent the development of acute lung injury (ALI). We tested the association of serum endocan levels with subsequent development of ALI after major trauma. Materials and MethodsThis was a single-center nested case-control study within a prospective cohort study of major trauma patients. Using an enzyme-linked immunosorbent assay test, we measured endocan levels from admission serum in 24 controls (no ALI) and 24 cases (ALI within 5 days of trauma). Multivariable logistic regression was used to test the association of admission serum endocan levels with subsequent ALI. ResultsPatients who developed ALI had lower levels of endocan on admission (mean, 3.5 ± 1.4 ng/mL vs 4.9 ± 2.6 ng/mL in controls; P = .02). For each 1-unit increase in serum endocan level, the odds ratio for ALI development decreased (0.69; 95% confidence interval, 0.49-0.97; P = .03). Lower endocan levels remained associated with a higher incidence of ALI after adjustment for age and illness severity. ConclusionsLower levels of serum endocan on admission are associated with subsequent development of ALI in trauma patients. These observations may be explained by endocan-mediated blockade of leukocyte recruitment in the lung.

Effects of peripheral blood stem cell apheresis on systemic cytokine levels in patients with multiple myeloma

BACKGROUND AIMS. Pro-angiogenic cytokines can affect myeloma cell proliferation directly and indirectly through stimulation of cancer-associated angiogenesis. METHODS. We investigated how peripheral blood stem cell (PBSC) collection affected plasma angioregulatory cytokine levels in 15 consecutive myeloma patients. RESULTS. Plasma levels of hepatocyte growth factor (HGF) were significantly increased prior to apheresis in patients compared with donors, and a further increase was detected immediately after PBSC apheresis. HGF levels decreased within 24 h, but were still higher than the levels in healthy donors, whose HGF levels were not altered by platelet apheresis. Pre-apheresis levels of other angioregulatory cytokines, angiopoietin-2 and vascular endothelial growth factor (VEGF), were also increased in patients, whereas angiopoietin-1, angiogenin and basic fibroblast growth factor levels did not differ from healthy controls. PBSC harvesting decreased angiopoietin-1 and VEGF levels, increased the microvascular endothelial cell marker endocan levels but did not affect the other mediators. CONCLUSIONS. Our results show that PBSC apheresis alters systemic angioregulatory profiles in myeloma patients. This cytokine modulation is not a general characteristic of all apheresis procedures and was not seen in healthy platelet donors.

Expression and distribution of endocan in human tissues

Endocan is a novel human endothelial cell specific molecule. Its expression is regulated by cytokines and vascular endothelial growth factor (VEGF). The distribution of endocan in normal human tissues, however, remains unclear. We examined the expression of endocan in normal human tissue using immunohistochemical stains. Endocan was expressed in actively proliferative or neogeneic tissues and cells such as glandular tissues, endothelium of neovasculature, bronchial epithelium, germinal centers of lymph nodes etc. Endocan was not present in silent or resting tissues or cells such as endothelium of great arteries and spleen etc. Our findings suggest that endocan may act as a marker for angiogenesis or oncogenesis and could be regarded as a candidate gene for inflammatory tissue, neoplasia, tumor development and metastasis. The expression level of endocan may assist early diagnosis and prognosis of some tumors.

Targeting the angiopoietin (Ang)/Tie-2 pathway in the crosstalk between acute myeloid leukaemia and endothelial cells: studies of Tie-2 blocking antibodies, exogenous Ang-2 and inhibition of constitutive agonistic Ang-1 release

Background: The Tie-2 receptor can bind its agonistic ligand Angiopoietin-1 (Ang-1) and the potential antagonist Ang-2. Tie-2 can be expressed both by primary human acute myeloid leukaemia (AML) cells and endothelial cells, and Tie-2-blocking antibodies are now being evaluated in clinical trials for cancer treatment. Design and methods: We investigated the effects of Tie-2-blocking antibodies, exogenous Ang-2 and pharmacological agents on AML cell proliferation and the release of angioregulatory mediators. Results: Tie-2-blocking antibodies had a growth inhibitory effect on human AML cells co-cultured with microvascular endothelial cells, but this inhibition was not observed when leukaemic cells were co-cultured with fibroblasts or osteoblasts. AML cell viability in co-cultures was not altered by anti-Tie-2. Furthermore, anti-Tie-2 decreased hepatocyte growth factor (HGF) levels and increased CXCL8 levels in co-cultures, whereas the levels of endocan (a proteoglycan released by endothelial cells) were not altered. The only significant effects of exogenous Ang-2 were decreased levels of HGF and endocan. Constitutive AML cell release of agonistic Ang-1 was decreased by the proteasomal inhibitor bortezomib and the specific IκB-kinase/NFκB inhibitor BMS-345541. Conclusion: We conclude that various strategies for inhibition of Tie-2-mediated signalling should be considered in AML therapy, possibly in combination with other antiangiogenic strategies.

Differential kinetics of endothelial cell activation biomarkers E-selectin and endocan during nonlethal endotoxemia in 129Sv mice: a role for PMN-derived serine proteases in the transient decrease of circulating endocan levels

Severe septic syndrome remains one of the most frequent causes of death in ICUs. One of the main players in this pathology is the endothelium integrity. Our laboratory has demonstrated in preliminary clinical studies among the various biomarkers of endothelial dysfunction that blood levels of endocan (ESM-1), a pulmonary vascular endothelial cell-specific molecule participating in the control of endothelial-leukocyte interactions, are associated with the severity and evolution of septic states. On the other hand, we showed in vivo that antiprotease therapy is associated with a decrease of the leukocyte rolling and firm leukocyte adhesion to endothelium in sepsis. This decrease in the leukocyte-endothelial cell contacts was associated with an increase of blood endocan levels, suggesting a linkage between leukocyte proteases, endocan, and inflammation during sepsis.

Endocan (endothelial cell-specific molecule-1) as a pertinent biomarker of endothelial dysfunction in sepsis

One of the main players in the severity of sepsis is the endothelium integrity. Endocan, also called endothelial cell-specific molecule-1 (ESM-1), was shown to be preferentially expressed in lung vasculature. Structurally, endocan/ESM-1 is a 50 kDa proteoglycan that can interact with ICAM-1 and LFA-1 integrins and consequently prevents inflammatory events. In an experimental rat endotoxemic shock model, we previously showed that a decrease in the leukocyte-endothelial cell contacts (induced by drugs) is clearly linked to an increase of blood endocan levels. Blood levels of endocan/ESM-1 were also shown to be associated with the severity and evolution of septic states in preliminary studies.

Vascular endocan (ESM‐1) is markedly overexpressed in clear cell renal cell carcinoma

In kidney cancer, new anti-angiogenic therapies have emerged requiring parameters of effectiveness. The aim was to analyse the expression of endocan or endothelial cell-specific molecule-1, which is a proteoglycan up-regulated in presence of pro-angiogenic factors. We investigated 44 renal clear cell carcinomas (RCC) and 25 papillary carcinomas (PC). Circulating endocan was detected by enzyme-linked immunosorbent assays (ELISA) in 14 patients with RCC, in eight with PC and in 15 healthy volunteers. Endocan was detected by immunohistochemistry in endothelial cells in almost all the cases of RCC without immunoreactivity in tumour cells. In PC, only 5/25 tumours exhibited weak immunoreactivity. Reverse transcriptase-polymerase chain reaction study confirmed that endocan levels were strongly increased in RCC. Endocan was also detected by ELISA at levels from 3- to 10-fold higher in the sera of patients with RCC. In vitro, addition of sunitinib prevented the release of endocan in human umbilical vascular endothelial cells when induced by vascular endothelial growth factor. Our results showed that endocan is overexpressed in patients with RCC. Endocan could therefore appear as a marker of interest in the follow-up and may be a potential parameter to monitor the tumour response to anti-angiogenic therapeutics.

A subset of patients with high-risk acute myelogenous leukemia shows improved peripheral blood cell counts when treated with the combination of valproic acid, theophylline and all- trans retinoic acid

Acute myelogenous leukemia (AML) patients (24 consecutive patients, median age 71 years, 17 high-risk disease) were treated with all- trans retinoic acid, theophylline and valproic acid. Among 22 evaluable patients 9 responded with increased normal peripheral blood cell counts. The responses could be classified as hematological improvement according to response criteria for patients with myelodysplastic syndromes (MDS) for four patients only. The nine patients with increased normal cell counts had a median survival from start of therapy of 147 days compared with 48 days for the other patients. Four patients fulfilling the MDS criteria had a survival ranging from 112 to 644 days. The treatment was associated with decreased in vitro cytokine-dependent AML cell proliferation and increased blood levels of Endocan and angiopoietin-2 both for responders and non-responders. We conclude that the therapy causes disease stabilization for a subset of AML patients.

In vivo biological effects of ATRA in the treatment of AML

Background: All-trans retinoic acid (ATRA) is mandatory in the treatment of acute promyelocytic leukaemia (APL). Experimental studies suggest that ATRA can induce differentiation and apoptosis in leukaemia cells also for other acute myelogenous leukaemia (AML) subtypes, but the clinical observations are conflicting. Design and methods: Twenty-two AML patients with non-APL disease received oral ATRA alone (22.5 mg/m2 twice daily) for two days, the patients thereafter continued ATRA together with valproic acid and theophylline. We investigated the biological effects of the initial 2 days treatment with ATRA alone. Serum/plasma samples were collected before and after 2 days of ATRA, peripheral blood AML cells were collected from all 12 patients with circulating leukaemia cells (ClinicalTrials.gov NCT00175812; EudraCT no. 2004-001663-22). Results: AML cells collected during therapy had altered flow cytometric forward and right angle light scatters but no morphological signs of differentiation. ATRA increased the percentage of circulating AML cells in G0/G1 phase for 9 out of 12 patients (p = 0.043). Circulating leukaemia cells derived during therapy had increased intracellular levels of P21 (mean increase in mean fluorescence intensity (MFI) being 18.2%, p = 0.017), and decreased levels of Gata-2 (mean decrease in MFI 19%, p = 0.026), NF-κB p65 (mean decrease in MFI 15.4%, p = 0.033) and Bcl-2 (mean decrease in MFI 7.2%, p = 0.005). In addition, increased systemic levels of the endothelial marker endocan (plasma) and the angioregulatory mediator angiopoietin-2 (serum) were observed. Conclusions: In vivo ATRA treatment in AML affects leukaemic cell morphology, regulation of cell cycle progression and apoptosis, and possibly also microvascular endothelial cell functions.

Endocan is a VEGF-A and PI3K regulated gene with increased expression in human renal cancer

An in vitro model of VEGF-A-induced angiogenesis was used to generate transcription profiles of human microvascular endothelial cells. Microarray analysis showed increased transcription of genes known to regulate angiogenesis, but also genes that previously have not been firmly associated with angiogenesis such as endocan, pinin, plakophilin, phosphodiesterase 4B and gelsolin. Increased endocan mRNA levels in response to VEGF-A in endothelial cells and in human renal cancer have previously been reported. We now show increased endocan protein levels in VEGF-A treated endothelial cells and in human renal clear cell carcinoma. Increased protein expression was observed both in tumor cells and in a subset of tumor vessels, while expression in normal kidney tissue was low. VEGF-A seemed to be a specific inducer of endocan transcription since FGF-2, PDGF-BB, HGF/SF and EGF did not alter expression levels. Inhibition of PI3K with LY294002 caused a 12-fold increase in endocan transcription suggesting a repressive function of PI3K. In contrast inhibition of Src or MEK, which are signaling pathways activated by VEGF-A, did not influence basal or VEGF-A-induced endocan levels. In conclusion our study shows that, among angiogenic growth factors, VEGF-A is a specific inducer of endocan transcription which is translated into increased protein levels in VEGF-A treated endothelial cells. Increased endocan protein expression in human renal cancer suggests a role in tumor growth.

Endocan Expression and Relationship with Survival in Human Non–Small Cell Lung Cancer

We evaluated the expression of endocan, a soluble lung- and kidney-selective endothelial cell-specific dermatan sulfate proteoglycan, in non-small cell lung tumors compared with normal lung and studied the significance of high levels of circulating endocan in patients with non-small cell lung cancer. Endocan and vascular endothelial growth factor mRNA expression were evaluated by semiquantitative PCR in tumoral and nontumoral lung tissue samples from a first series of 24 patients submitted to curative surgery. Relationships between survival, time to tumor progression, and serum levels of endocan were evaluated in a second series of 30 previously untreated patients addressed for staging. In non-small cell lung cancers, endocan mRNA was overexpressed compared with control lung. Immunohistochemistry shows that endocan was expressed only by tumor endothelium in all cases, especially in the periphery of the tumors, with no differences between adenocarcinoma and squamous cell carcinoma. Endocan and vascular endothelial growth factor mRNA expression was positively correlated in lung tumors. Serum endocan levels, as well as tumor, node, and metastasis status, were correlated with both survival and time to tumor progression. However, endocan serum level was not an independent prognostic factor due to its correlation with the presence of metastasis. Endocan is overexpressed in non-small cell lung tumors compared with healthy lung and probably represents a response of tumoral endothelium to proangiogenic growth factor stimulation. Circulating levels of endocan might reflect tumor angiogenic stimulation and present prognostic significance.

Endocan, a new endothelial marker in human sepsis*

a) To evaluate in septic patients the blood levels of endocan, a circulating proteoglycan, which regulates leukocyte function-associated antigen-1/intercellular adhesion molecule-1 interactions in vitro; b) to determine whether endocan could be used as a diagnostic and prognostic marker in sepsis in the intensive care unit; and c) to study kinetics of endocan secretion by endothelial cells in vitro after stimulation by soluble mediators involved in sepsis. Prospective observational study. Intensive care unit of the University Hospitals of Lille, France, and Geneva, Switzerland. All patients admitted to the intensive care unit over a 6-month period with clinical evidence of severe sepsis or septic shock. None. In vitro, we showed a sustained endocan secretion by endothelial cells after stimulation by lipopolysaccharide and tumor necrosis factor-alpha. Circulating levels of endocan measured in 63 patients admitted to the intensive care unit with sepsis were significantly elevated compared with 20 healthy donors and seven patients with systemic inflammatory response syndrome: 2.71 +/- 4.88 ng/mL vs. 0.77 +/- 0.44 ng/mL vs. 0.68 +/- 1.03 ng/mL (median +/- interquartile range, p < .001). Endocan levels were higher in patients with septic shock (6.11 +/- 12.99 ng/mL, n = 22) than in patients with severe sepsis (1.97 +/- 7.8 ng/mL, n = 12) or sepsis (1.95 +/- 1.63 ng/mL, n = 29). Measurement of endocan at intensive care unit admission revealed higher levels in nonsurvivors (n = 12) than in patients still alive 10 days later (n = 51, 6.98 +/- 13.8 vs. 2.45 +/- 4.09, p < .01). These results suggest that in septic patients, endocan blood level is related to the severity of illness and the outcome of the patient and may represent a novel endothelial cell dysfunction marker.

005 Endocan, a potential new endothelial marker in human sepsis

Resume Introduction We previously reported that serum levels of endocan, an endothelial derived dermatan sulphate proteoglycan which regulates LFA-1/ ICAM-1 interactions in vitro , are elevated in patients with sepsis. As the endothelium is an important player in sepsis, and endothelial activation parallel sepsis severity, we wonder if blood levels of endocan could be used as a diagnostic and prognostic marker in sepsis and how it compares with previously pro-posed markers as von Willebrand factor, IL6, IL 10, Procalcitonin or C reactive protein. We also studied kinetics of endocan secretion by endothelial cells in vitro after stimulation by soluble mediators involved in sepsis. Material and methods Endocan values were quantified by an in house sandwich type ELISA. Commercial assays were used for procalcitonin, C reactive protein, IL10, IL6, von Willebrand Factor. Design Prospective observational study. Setting Intensive care unit (ICU) of the University Hospitals of Lille, France, and Geneva, Switzerland. Patients All patients admitted to the intensive care unit over a 6-month period with clinical evidence of sepsis. Interventions None. Measurements and main results In vitro , we showed a sustained endocan secretion by endothelial cells after stimulation by LPS and TNFα. Circulating levels of endocan measured in 63 patients admitted in ICU with sepsis were significantly elevated compared to 20 healthy donors and 7 SIRS patients: 2.71 ± 4.88 ng/ml vs 0.77 ± 0.44 ng/ml vs 0.68 ± 1.03 ng/ml (median ± interquartile range) (p Conclusions These results suggest that in septic patients, endocan blood level is related to the severity and to the outcome of the patients, and may represent a novel endothelial cell dysfunction marker.

Purification and characterization of endocan (endothelial cell‐specific molecule‐1), a circulating proteoglycan involved in tumour progression and inflammatory diseases

Introduction By virtue of the multiplicity of their protein‐binding partners (e.g. growth factors, cytokines/chemokines), proteoglycans have been shown to be involved in the regulation of a large number of pathophysiological processes including cancer and inflammatory diseases. We have studied and characterized endocan, also called endothelial cell‐specific molecule‐1 (ESM‐1), which represents a new group of circulating proteoglycans. Endocan is mainly expressed by endothelial cells but also by epithelial cells from lung, gut and kidney. Structurally, endocan is constituted of a mature polypeptide of 165 amino acids with a single glycosaminoglycan chain covalently linked to the serine at position 137 (Béchard et al. 2001).Methods and results We showed that human umbilical vein endothelial cells expressed endocan specifically with a single chain of dermatan sulfate (DS) as glycosaminoglycan moiety. As shown by surface plasmon resonance, the DS chain directly interacts with cytokines and growth factors including hepatocyte growth factor/scatter factor and could be responsible for endocan's biological activities. Human embryonic kidney 293 cells, which have been genetically engineered to overexpress endocan, induce tumour growth when injected subcutaneously in SCID mice. Moreover, inflammatory cytokines such as TNF‐a and IL‐1 have been shown to increase the synthesis and the secretion of endocan from human umbilical vein endothelial cells.Conclusion These results suggest that circulating levels of endocan may represent a novel marker for cancer and inflammatory diseases. Further studies on its GAG structure could help us to better understand the biological activities of endocan and to design future glycomic‐based therapies.

CALPAIN INHIBITORS IMPROVE MYOCARDIAL DYSFUNCTION AND INFLAMMATION INDUCED BY ENDOTOXIN IN RATS

Excessive activation of calpains has been implicated in the pathophysiology of inflammation, trauma, and ischemia reperfusion injury. Here, we investigated the effects of calpain inhibition on myocardial dysfunction and inflammation induced by endotoxin in rats. Rats were treated i.v. with endotoxin (10 mg/kg) or endotoxin plus calpain inhibitors and were then prepared after 4 h for myocardial contractility assessment, detection of endothelium leukocyte interactions, and plasma TNF-alpha, nitrite/nitrate, and endocan levels. Compared with vehicle-treated rats, hearts from endotoxin-treated rats had reduced systolic performance that was partially prevented by calpain inhibitors, i.e., acetyl-leucyl-leucyl-arginal (leupeptin), carbobenzoxy-valyl-phenylalanial (calpain inhibitor III), and N-acetyl-leucinyl-leucinyl-norleucinal (ALLN). Leupeptin and calpain inhibitor III reduced plasma TNF-alpha levels in endotoxin-treated rats. ALLN reduced plasma TNF-alpha and nitrite/nitrate levels in endotoxin-treated rats. Endotoxin treatment increased mesenteric venule leukocyte rolling (10 +/- 3 leukocytes/min vs. 44 +/- 10 leukocytes/min; P < 0.01) and adhesion (2 +/- 2 leukocytes/min vs. 15 +/- 3 leukocytes/min; P < 0.01), which was reduced by calpain inhibitors. Attenuation of leukocyte endothelium interactions observed in calpain inhibitor-treated rats with sepsis was associated with increases in plasma anti-adhesion molecule endocan. In conclusion, calpain inhibitors improved endotoxin-induced cardiac dysfunction, which may be attributed to the modulation of endothelium leukocyte interactions in the inflamed vasculature.