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.

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.

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.

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.

Endocan regulates acute lung inflammation through control of leukocyte diapedesis.

Acute respiratory distress syndrome is a severe form of respiratory failure, occurring in up to 20% of patients admitted to the intensive care unit with sepsis. Dysregulated leukocyte diapedesis is a major contributor to acute respiratory distress syndrome. Endocan is a circulating proteoglycan that binds to the leukocyte integrin leukocyte functional antigen-1 and blocks its interaction with its endothelial ligand, ICAM-1. The objective of this study was to evaluate the role of endocan in the control of acute lung inflammation. In vitro, endocan inhibited human leukocyte transendothelial migration as well as ICAM-1-dependent migration but had a very mild effect on ICAM-1-dependent adhesion. Endocan also acted as an inhibitor of transendothelial migration of mouse leukocytes. The effect of systemic administration of recombinant human endocan was assessed in a model of acute lung inflammation in BALB/c mice. Treatment with endocan 1 h after intratracheal LPS challenge reduced the alveolar inflammatory response, diminished histological features of acute lung injury, and improved respiratory function. These results highlight the anti-inflammatory role of human endocan and its protective effect against acute lung injury.NEW & NOTEWORTHY We show here that endocan inhibits ICAM-1-dependent human leukocyte transendothelial migration and ICAM-1-dependent adhesion. We also found that in BALB/c mice with tracheal LPS-induced acute lung injury treatment with recombinant human endocan reduces lung inflammation, notably through reduction of neutrophilic recruitment, and restores normal lung function. These results confirm the hypothesis that human endocan may have a protective effect against acute lung inflammation.

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.

Low endocan levels are predictive of Acute Respiratory Distress Syndrome in severe sepsis and septic shock.

PURPOSE: Endocan is a circulating proteoglycan measured at high blood levels during severe sepsis, with a likely lung anti-inflammatory function. The aim of this study was to assess whether paradoxically low endocan levels at Intensive Care Unit (ICU) admission could predict Acute Respiratory Distress Syndrome (ARDS) within 72 h in severe septic patients. MATERIALS AND METHODS: Patients admitted for severe sepsis in the ICU of a French University Hospital were included in a prospective single-center observational study between October 2014 and March 2016. RESULTS: 72 patients admitted in ICU for severe sepsis were included. Endocan blood values at inclusion were significantly lower in patients who developed an ARDS at 72 h (p < 0.001). For endocan blood values > 5.36 ng/mL, the adjusted OR for development of ARDS at 72 h was of 0.001 (95% CI 0-0.215; p = 0.011). In our cohort, an endocan value < 2.54 ng/mL predicted ARDS at 72 h with a positive predictive value of 1 (Sp = 1 (95% CI 0.94-1)). CONCLUSIONS: In a cohort of severe septic patients, we observed that low blood levels of endocan at ICU admission were predictive of ARDS at 72 h.

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).

Is Endocan a Diagnostic Marker for Pneumonia After Cardiac Surgery? The ENDOLUNG Study.

BACKGROUND: Postoperative pneumonia is frequent after cardiac surgery and is associated with increased morbidity and mortality. We tested the hypothesis that endocan is an early biomarker for the detection of pneumonia after cardiac surgery. METHODS: Between January and May 2016, 155 patients scheduled to undergo elective cardiac surgery with cardiopulmonary bypass were prospectively included in the study. Serum level of endocan was measured at five timepoints (preoperative, and at 6, 24, 48, and 72 hours after the end of surgery). Procalcitonin and C-reactive protein were measured at 24 and 72 hours. The preoperative and postoperative characteristics of the patients were recorded. Independent predictors of postoperative pneumonia were identified by logistic regression. Threshold values of endocan predictive of postoperative pneumonia were determined using receiver-operating characteristics curve analysis. RESULTS: Seventeen patients (11%) had pneumonia after surgery. Endocan greater than 3.7 ng/mL before induction of anesthesia, or greater than 12.1 ng/mL at 6 hours after surgery, as well body mass index higher than 27 kg/m2 and duration of surgery were independent predictors of postoperative pneumonia. At induction of anesthesia, an endocan cutoff value of 3.7 ng/mL had 65% sensitivity and 72% specificity for the prediction of postoperative pneumonia; whereas at 6 hours, with a cutoff value of 12.1 ng/mL, these values were 71% and 75%, respectively. The time saved by endocan dosage compared with clinical diagnosis of postoperative pneumonia was 96 hours. CONCLUSIONS: This study shows that endocan is an early marker of postoperative pneumonia in patients after cardiac surgery.

Endocan is a stable circulating molecule in ICU patients.

BACKGROUND: Endocan is a lung endothelial cell secreted proteoglycan, possessing multiple physiological roles and potential therapeutic and diagnostic utility as biomarker in pneumonia and acute respiratory distress syndrome. Endocan synthesis and secretion can be induced by proinflammatory cytokines such as TNF-α, but can also be subject of proteolytic degradation causing preanalytical variation. METHODS: We investigated the stability of endocan in conventional serum, plasma, anticoagulated whole blood, as well as whole blood and plasma stabilized with protease inhibitors. RESULTS: Among the recipient tubes for blood collection, those with EDTA gave minimal interference. No dilution effect was observed on recovery tests from 1:2 to 1:16 (v:v). The recovery test in 10 plasma EDTA samples from healthy subjects or septic patients indicated a median recovery of 104.5% [104%-107.5%], and 97% [88.5%; 102.5%], respectively. Patient's plasma endocan remains stable when stored at room temperature till 72h, or following 3 freeze thaw cycles. Finally, no interference was observed with hemolytic, icteric or turbidic plasma samples. CONCLUSION: These results are consistent with the view that endocan measured in ICU patients is intact, stable, and accurate. Then, the low endocan level observed in ICU patients who developed ARDS is likely to be reliable.

Increased Extravascular Lung Water and Plasma Biomarkers of Acute Lung Injury Precede Oxygenation Impairment in Primary Graft Dysfunction After Lung Transplantation.

BACKGROUND: After lung transplantation (LT), early prediction of grade 3 pulmonary graft dysfunction (PGD) remains a research gap for clinicians. We hypothesized that it could be improved using extravascular lung water (EVLWi) and plasma biomarkers of acute lung injury. METHODS: After institutional review board approval and informed consent, consecutive LT recipients were included. Transpulmonary thermodilution-based EVLWi, plasma concentrations of epithelial (soluble receptor for advanced glycation endproducts [sRAGE]) and endothelial biomarkers (soluble intercellular adhesion molecule-1 and endocan [full-length and cleaved p14 fragment]) were obtained before and after LT (0 [H0], 6, 12, 24, 48 and 72 hours after pulmonary artery unclamping). Grade 3 PGD was defined according to the International Society for Lung and Heart Transplantation definition, combining arterial oxygen partial pressure (PaO2)/inspired fraction of oxygen (FiO2) ratio and chest X-rays. Association of clinical risk factors, EVLWi and biomarkers with grade 3 PGD was analyzed under the Bayesian paradigm, using logistic model and areas under the receiver operating characteristic curves (AUCs). RESULTS: In 47 LT recipients, 10 developed grade 3 PGD, which was obvious at H6 in 8 cases. Clinical risk factors, soluble intercellular adhesion molecule-1 and endocan (both forms) were not associated with grade 3 PGD. Significant predictors of grade 3 PGD included (1) EVLWi (optimal cutoff, 13.7 mL/kg; AUC, 0.74; 95% confidence interval [CI], 0.48-0.99), (2) PaO2/FiO2 ratio (optimal cutoff, 236; AUC, 0.68; 95% CI, 0.52-0.84), and (3) sRAGE (optimal cutoff, 11 760 pg/mL; AUC, 0.66; 95% CI, 0.41-0.91) measured at H0. CONCLUSIONS: Immediate postreperfusion increases in EVLWi and sRAGE along with impaired PaO2/FiO2 ratios were early predictors of grade 3 PGD at or beyond 6 hours and may trigger early therapeutic interventions.

Relevance of Endothelial Cell-Specific Molecule 1 (Endocan) Plasma Levels for Predicting Pulmonary Infection after Cardiac Surgery in Chronic Kidney Disease Patients: The Endolung Pilot Study.

OBJECTIVES: This pilot study aimed to evaluate the relevance of endocan plasma levels for predicting pulmonary infection after cardiac surgery in patients with chronic kidney disease (CKD). METHODS: Serum collected in a previous prospective cohort study (from 166 patients with preoperative CKD who underwent cardiac surgery) was used. Five patients with postoperative pulmonary infection were compared with 15 randomly selected CKD patients with an uneventful outcome. Blood samples were tested at 4 time points (preoperatively and 6, 12, and 24 h after the end of surgery). Endocan, procalcitonin, and C-reactive protein plasma levels were compared between the two groups. RESULTS: At 6 h, the patients with pulmonary infection had significantly higher levels of endocan than the patients without pulmonary infection (24.2 ± 15.6 vs. 6.4 ± 3.2 ng/mL; p = 0.03). A receiver operating characteristic curve analysis showed 80% sensitivity and 100% specificity for endocan to predict pulmonary infection (area under the curve 0.84), with a cutoff value of 15.9 ng/mL. The time saved by assessment of the endocan dosage compared to a clinical diagnosis of pulmonary infection was 47 h. CONCLUSION: This pilot study showed that a specific study to assess the link between endocan plasma levels and pulmonary infection after cardiac surgery in CKD patients is of potential utility.