The effect of supplemental oxygen and continuous positive airway pressure withdrawal on endocan levels.

PURPOSE: Endocan is a biomarker of endothelial dysfunction, which is a precursor to cardiovascular disease. Obstructive sleep apnoea (OSA) is associated with elevated endocan levels but the effects of treatment on endocan levels in OSA are not fully established. We aimed to determine whether endocan levels could be detected by immunoassay and to determine the effect of supplemental oxygen during continuous positive airway pressure (CPAP) withdrawal on circulating endocan levels. METHODS: We conducted an exploratory analysis from a randomised controlled crossover study which included participants with OSA. Participants stopped their CPAP therapy and were randomised to receive either supplemental oxygen or sham for 14 nights before crossing over. Supplemental oxygen blocked the rise in blood pressure seen in the sham group. We analysed plasma endocan levels by immunoassay at baseline and after 14 nights of intervention in both groups. RESULTS: Twenty-five participants were included, with a total of 100 samples. Endocan levels were detectable at all time points in 22 participants (88%), and in 93 (93%) samples. Supplemental oxygen had no effect on endocan levels compared to sham (+ 0.52 ng/ml, 95%CI -0.21 to + 1.25, p = 0.16), and there was no significant difference in endocan levels from baseline to follow-up in either the sham (-0.30 ng/ml, 95%CI -0.89 to + 0.30, p = 0.31) or supplemental oxygen (+ 0.22 ng/ml, 95%CI 0.00 to + 0.44, p = 0.05) arm. CONCLUSIONS: We have shown that endocan levels are detectable before and after CPAP withdrawal. However, we found no effect of supplemental oxygen following CPAP withdrawal on circulating endocan levels. TRIAL REGISTRATION AND DATE: ISRCTN 17,987,510 19/02/2015.

Impact of early postoperative blood glucose variability on serum endocan level in cardiac surgery patients: a sub study of the ENDOLUNG observational study.

BACKGROUND: Early postoperative glycemic variability is associated with worse outcome after cardiac surgery, but the underlying mechanisms remain unknown. This study aimed to describe the relationship between postoperative glycemic variability and endothelial function, as assessed by serum endocan level in cardiac surgery patients. METHODS: We performed a post hoc analysis of patients included in the single-center observational ENDOLUNG study. Adult patients who underwent planned isolated coronary artery bypass graft surgery were eligible. Postoperative glycemic variability was assessed by calculating the coefficient of variability (CV) of blood glucose measured within 24 (CV24) and 48 (CV48) hours after surgery. Serum endocan level was measured at 24 (Endocan24) and 48 (Endocan48) hours after surgery. Pearson's correlation coefficient with 95% confidence interval (95% CI) was calculated between CV24 and Endocan24, and between CV48 and Endocan48. RESULTS: Data from 177 patients were analyzed. Median CV24 and CV48 were 18% (range 7 to 39%) and 20% (range 7 to 35%) respectively. Neither CV48 nor CV24 were significantly correlated to Endocan48 and Endocan24 respectively (r (95% CI) = 0.150 (0.001 to 0.290; and r (95% CI) = 0.080 (-0.070 to 0.220), respectively). CONCLUSIONS: Early postoperative glycemic variability within 48 h after planned cardiac surgery does not appear to be correlated with postoperative serum endocan level. CLINICAL TRIAL REGISTRATION NUMBER: NCT02542423.

Kinetics of endocan in patients undergoing cardiac surgery with and without cardiopulmonary bypass.

BACKGROUND: Endocan plays an important role in the processes of inflammation and infection. The use of cardiopulmonary bypass (CPB) during cardiac surgery can induce an inflammatory response. We aimed to describe the kinetics of endocan in patients undergoing cardiac surgery with and without the use of CPB. METHODS: Single-centre, observational study with retrospective analysis of prospectively collected data, to compare the kinetics of endocan in patients undergoing isolated coronary artery bypass graft (CABG) surgery. Endocan was measured at induction of general anesthesia (baseline), and at 6, 24, 48 and 72 h after the end of surgery. Patients were classified into two groups, namely those undergoing CPB (CPB group) and those without CPB (off-pump group). RESULTS: In total, 91 patients were included in this analysis: 61 patients in the CPB group and 30 in the off-pump group. There were no major significant differences between groups. Patients with CPB had a significantly higher level of endocan at 6 h (9.7 ±â€¯6.7 ng/ml vs 6.9 ±â€¯3.3 ng/ml, p = 0.03), but the difference was no longer statistically significant at subsequent timepoints. Endocan values were not significantly correlated with the duration of CPB (p = 0.53). CONCLUSION: Endocan levels in patients undergoing isolated CABG surgery with CPB are significantly higher at 6 h than in patients with off-pump surgery, and peaks earlier in those with CPB (6 h) than in those undergoing off-pump surgery (24 h).

Endocan, sepsis, pneumonia, and acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) and hospital-acquired pneumonia (HAP) are major problems of public health in intensive care units (ICUs), occurring in 15% of critically ill patients. Among the factors explaining ARDS development, sepsis is known as a frequent cause. Sepsis, ARDS, and HAP increase morbidity, mortality, length of stay in the ICU, and the overall costs of healthcare. The major challenge remains to identify accurately among critically ill patients those at risk of poor outcomes who could benefit from novel therapies. Endocan is released by the pulmonary endothelium in response to local or systemic injury. It inhibits mainly leukocyte diapedesis rather than leukocyte rolling or adhesion to the endothelial cells both in vitro and in vivo. Endocan was evaluated in 25 clinical reports, including 2454 critically ill patients and 452 healthy controls. The diagnostic value of endocan for sepsis or sepsis severity was equal to procalcitonin but its prognostic value was better. A predictive value for postoperative pneumonia was evidenced in two studies, and a predictive value for ARDS in four studies from three independent centers. This review presents an overview of the structure, expression, and functions of endocan. We also hereby summarize the potential applications of endocan in the prediction and prognosis of ARDS and HAP, as well as in the prognosis of sepsis.

Evaluation of endothelial biomarkers as predictors of organ failures in septic shock patients.

BACKGROUND: Endothelial injury is recognized to trigger organ failures during the first 48h of septic shock. We evaluate endothelial biomarkers at ICU admission in their ability to predict severity, outcome, and organ failures in septic shock patients. METHODS: This prospective observational pilot study was conducted in a medical intensive care unit of a university hospital. Plasma levels of endothelial biomarkers as angiopoietin-2, sE-selectin or endocan were measured at ICU admission of 20 patients presenting with septic shock. Clinical and biological data were recorded at inclusion and each day during the first week. RESULTS: Significant correlations were found between angiopoietin-2 and severity scores at Day 1: SAPS2 (r(2)=0.620; p=0.004) and LOD score (r(2)=0.681; p=0.001). The angiopoietin-2 level was significantly higher in patients presenting with organ failure such as hemodynamic, renal or hepatic failure. It correlated with catecholamine infusion dose and was higher in non survivors compared with survivors (33.5 [28.9-51.4] vs. 12.4 [6.4-14.7]ng/ml; p=0.001). In contrast, in that population presenting with septic shock, endocan level at inclusion was not related to any organ failure at inclusion or Day 1 but appeared lower in patients presenting with respiratory failure at Day 3 compared to those who do not (1.9 [0.99-3.1] vs 5.2 [3.1-17.2]ng/ml; p=0.032). The endocan level at inclusion was correlated with the decrease in PaO2/FiO2 ratio at Day 2 (r(2)=0.628; p=0.0004) and Day 3 (r(2)=0.645; p=0.005). Endocan level <2.54ng/ml at admission is predictive of a respiratory failure presence at Day 3. CONCLUSION: In septic shock patients, angiopoietine-2 is related with clinical severity during the first 24h but only endocan is able to predict the presence of respiratory failure at Day 3.

The disulfide bond between cysteine 10 and cysteine 34 is required for CCL18 activity.

Asthma is a Th2-mediated disease that involves Th2 cell and eosinophil migration into the bronchial mucosa which is dependent upon the expression of a specific set of chemokines within the lung. Among them, CCL18 seems to play a key role because of its preferential expression in the lung, and its up-regulation by Th2 cytokines. Here, we show that the optimal naïve T cell and basophil chemotaxis, and basophil histamine release induced by rhCCL18 occurred at a 100 time lower concentration with CHO-derived rhCCL18 than with E. coli-derived rhCCL18. FT-ICR mass spectrometry of the intact chemokines showed that the rhCCL18 produced by CHO cells contained the 2 disulfide bonds Cys10-Cys34 and Cys11-Cys50, in clear contrast to the rhCCL18 derived from E. coli where the Cys10-Cys34 bond was absent. We found that reduction of the Cys10-Cys34 of the CHO-derived rhCCL18 resulted in a shift of its activity, reaching the same level as the E. coli-derived rhCCL18. These results demonstrate that the Cys10-Cys34 disulfide bond is involved in the function of CCL18.

Evaluation of Endocan as a Treatment for Acute Inflammatory Respiratory Failure.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a life-threatening condition resulting from acute pulmonary inflammation. However, no specific treatment for ARDS has yet been developed. Previous findings suggest that lung injuries related to ARDS could be regulated by endocan (Esm-1). The aim of this study was to evaluate the potential efficiency of endocan in the treatment of ARDS. METHODS: We first compared the features of acute pulmonary inflammation and the severity of hypoxemia in a tracheal LPS-induced acute lung injury (ALI) model performed in knockout (Esm1-/-) and wild type (WT) littermate C57Bl/6 mice. Next, we assessed the effects of a continuous infusion of glycosylated murine endocan in our ALI model in Esm1-/- mice. RESULTS: In our ALI model, we report higher alveolar leukocytes (p < 0.001), neutrophils (p < 0.001), and MPO (p < 0.001), and lower blood oxygenation (p < 0.001) in Esm1-/- mice compared to WT mice. Continuous delivery of glycosylated murine endocan after LPS-induced ALI resulted in decreased alveolar leukocytes (p = 0.012) and neutrophils (p = 0.012), higher blood oxygenation levels (p < 0.001), and reduced histological lung injury (p = 0.04), compared to mice treated with PBS. CONCLUSIONS: Endocan appears to be an effective treatment in an ARDS-like model in C57Bl/6 mice.

Double-stranded RNA exacerbates pulmonary allergic reaction through TLR3: implication of airway epithelium and dendritic cells.

Respiratory viral infections have been implicated in exacerbations of allergic asthma, characterized by a Th2-biased immune response. Respiratory viruses target airway epithelial cells and dendritic cells (DCs). Their activation is, at least in part, mediated by the TLR3-dependent recognition of virus-derived dsRNA. To elucidate the role of epithelial cells and DCs and the implication of TLR3/Toll/IL-1R domain-containing adaptor-inducing IFN-beta (TRIF) pathway, we developed a mouse model of lung allergic exacerbation. The effect of intranasal administration of dsRNA in OVA-sensitized wild-type mice and TRIF(-/-) mice was evaluated on airway hyperresponsiveness and pulmonary inflammation. Our data demonstrated that treatment with dsRNA significantly increased the airway hyperresponsiveness, the lung inflammation, and the OVA-specific Th2 response. This was associated with an infiltrate of eosinophils, myeloid DCs, and T lymphocytes. TRIF activation was required for the development of dsRNA-induced exacerbation of the allergic reaction. Intratracheal transfer of IL-4/dsRNA/OVA-pretreated DCs also triggered exacerbation of the allergic reaction, whereas cells primed with dsRNA/OVA had a more limited effect. dsRNA-induced production of CCL20 by airway epithelium was associated with DC recruitment. In vivo and in vitro treatment with dsRNA amplified airway epithelial production of the pro-Th2 chemokines CCL11 and CCL17, their secretion being enhanced by Th2 cytokines. In conclusion, dsRNA derived from respiratory viruses trigger exacerbation of the pulmonary allergic reaction through TLR3/TRIF-dependent pathway. Moreover, Th2 cytokines participate in this process by modulating the response of airway epithelium and DCs to dsRNA.

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.

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.

Characterization and binding activity of the chondroitin/dermatan sulfate chain from Endocan, a soluble endothelial proteoglycan.

Endocan is a recently identified soluble chondroitin/dermatan sulfate (CS/DS) proteoglycan. Synthesized by endothelial cells, it has been found to be over-expressed in the vasculature surrounding a number of tumors, and by promoting growth factor mitogenic activities, hepatocyte growth factor/scatter factor (HGF/SF) in particular, it supports cellular proliferation. In this work, we characterized the glycosaminoglycan (GAG) chain of Endocan, purified either from the naturally producing human umbilical vein endothelial cells (HUVEC) or from a recombinant over-expression system in human embryonic kidney cells (HEK). Compositional analysis using different chondroitinases as well as nuclear magnetic resonance studies revealed that the GAG chains from both sources share many characteristics, with the exception of size (15 and 40 kDa, respectively, for HUVEC and HEK-293 cells). The DS-specific, IdoA-containing disaccharides contribute 30% of the chain (15% of which are 2-O-sulfated) and are mostly clustered in tetra- (35%), hexa- (12%), and octa- (5%) saccharide domains. Highly sulfated D, E, and B disaccharide units (HexA2S-GalNAc6S, HexA-GalNAc4S6S, and HexA2S-GalNAc4S) were also detected in significant amounts in both chains and may account for the HGF/SF-binding activity of the CS/DS. This work establishes that HEK-293 cells can be engineered to provide a valuable source of Endocan with authentic CS/DS chains, enabling the purification of sufficient amounts for structural and/or binding analysis and providing a possible model of Endocan CS/DS chain organization.

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

AIMS: 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. METHOD AND RESULTS: 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. CONCLUSIONS: 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.

Cleaved endocan acts as a biologic competitor of endocan in the control of ICAM-1-dependent leukocyte diapedesis.

Dysregulated leukocyte diapedesis is a major contributor to acute severe inflammatory states like sepsis and acute respiratory distress syndrome, which are common conditions in critically ill subjects. Endocan is a circulating proteoglycan that binds to the leukocyte integrin LFA-1 and blocks its interaction with its endothelial ligand ICAM-1, subsequently leading to the inhibition of leukocyte recruitment. Recent data have highlighted the hypothetic role of p14, endocan's major catabolite found in the bloodstream of septic patients, as a potential antagonist of endocan, thus participating in the regulation of acute inflammation. We hereby characterize the role of p14 as a biologic competitor of endocan, through assessment of its molecular interactions with LFA-1, endocan, and ICAM-1, as well as its effects on human leukocyte trafficking. Using immunodetection assay, we report that p14 can bind to LFA-1, thus inhibiting the interaction between LFA-1 and endocan, which in turn leads to the restoration of the ICAM-1/LFA-1 interaction. In primary human T cells trafficking assays, we underline the absence of effect of p14 on ICAM-1-dependent adhesion and migration, as well as on transendothelial migration. However, in those models, p14 reverses the antimigratory effect of endocan. To conclude, our study supports the hypothesis of an antagonistic role of p14 versus endocan in its effect on the LFA-1/ICAM-1-dependent human leukocyte recruitment.