Endocan as a potential marker in diagnosis and predicting disease severity in COVID-19 patients: a promising biomarker for patients with false-negative RT-PCR

Endocan as a marker of endotheliitis in COVID-19 patients: modulation by veno-venous extracorporeal membrane oxygenation, arterial hypertension and previous treatment with renin-angiotensin-aldosterone system inhibitors

BACKGROUND AND AIMS

Endocan has been scarcely explored in COVID-19, especially regarding its modulation by veno-venous extracorporeal membrane oxygenation (VV-ECMO), hypertension or previous renin-angiotensin-aldosterone system (RAAS) inhibitors treatment. We compared endocan and other endotheliitis markers in hospitalized COVID-19 patients and assessed their modulation by VV-ECMO, hypertension and previous RAAS inhibitors treatment.

MATERIAL AND METHODS

Serum endocan, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin were measured in "severe" (n = 27), "critically ill" (n = 17) and "critically ill on VV-ECMO" (n = 17) COVID-19 patients at admission, days 3-4, 5-8 and weekly thereafter, and in controls (n = 23) at a single time point.

RESULTS

Admission endocan and VCAM-1 were increased in all patients, but "critically ill on VV-ECMO" patients had higher endocan and E-Selectin. Endocan remained elevated throughout hospitalization in all groups. "Severe" and "critically ill" hypertensive patients or previously treated with RAAS inhibitors had higher endocan and/or VCAM-1, but in VV-ECMO patients the raised endocan values seemed unrelated with these factors. Among all COVID-19 hypertensive patients, those with previous RAAS inhibitors treatment had higher endocan.

CONCLUSIONS

In our study, endocan stands out as the best marker of endotheliitis in hospitalized COVID-19 patients, being upregulated by VV-ECMO support, hypertension and previous RAAS inhibitor treatment.

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.

Role of Serum Endocan Levels in Children with Bacterial and Viral Pneumonia: A Prospective, Case-Control Study

Introduction and Objective: Endocan has been used as a biomarker in the differential diagnosis of pulmonary diseases in adults. However, there are only a limited number of studies on its use in children. In this context, the objective of this study is to evaluate the relationship between serum endocan levels in children with bacterial and viral pneumonia. Materials and Methods: The population of this prospective case-control study consisted of hospitalized children aged 1 month to 15 years diagnosed with pneumonia between August 2020 and July 2021, whereas the control group consisted of randomly selected healthy children. The demographic and clinical characteristics of all participants were recorded. Participants' endocan levels, white blood cell (WBC) and neutrophil counts, and C-reactive protein (CRP) and procalcitonin (PCT) levels were measured within the scope of the laboratory tests. Results: The study sample consisted of 41 children, of whom 21 had bacterial pneumonia and 20 had viral pneumonia, whereas the control group consisted of 47 healthy children. Serum endocan levels, WBC and neutrophil counts, and PCT and CRP levels were significantly higher in children with bacterial pneumonia than in children with viral pneumonia and healthy children (P < 0.05). Additionally, serum endocan levels were significantly higher in children with viral pneumonia than in healthy children (P < 0.001). The endocan levels in children with bacterial pneumonia were significantly associated with the need for intensive care (P = 0.004) and correlated with the length of hospital stay (LoS) (r = 0.592, P = 0.005). Conclusion: The findings of this study indicated that serum endocan levels can be used in the differential diagnosis of bacterial and viral pneumonias. Additionally, it was found that the need for intensive care and LoS were significantly correlated with endocan levels in children with bacterial pneumonia.

Plasma Endocan as a Biomarker of Thrombotic Events in COVID-19 Patients

(1) Background: Endocan is a marker of endothelial dysfunction that may be associated with thrombotic events. The aim of the study was to investigate the performance of endocan as a marker of thrombotic events in COVID-19 patients. (2) Methods: We measured endocan in plasma from 79 documented COVID-19 patients classified according to disease severity (from mild to critical). Thrombotic events were recorded. (3) Results: Endocan concentrations at admission were significantly increased according to COVID-19 severity. Levels of endocan were significantly increased in patients experiencing thrombotic events in comparison with those without (16.2 (5.5−26.7) vs. 1.81 (0.71−10.5) ng/mL, p < 0.001). However, endocan concentrations were not different between pulmonary embolism and other thrombotic events. The Receiver Operating Characteristic (ROC) analysis for the identification of thrombotic events showed an area under the ROC curve (AUC) of 0.776 with an optimal threshold at 2.83 ng/mL (93.8% sensitivity and 54.7% specificity). When combining an endocan measurement with D-dimers, the AUC increased to 0.853. When considering both biomarkers, the Kaplan−Meier survival curves showed that the combination of endocan and D-dimers better discriminated patients with thrombotic events than those without. The combination of D-dimers and endocan was independently associated with thrombotic events. (4) Conclusions: Endocan might be a useful and informative biomarker to better identify thrombotic events in COVID-19 patients.

Serum Endocan Levels and Subclinical Atherosclerosis in Patients with Chronic Kidney and End-Stage Renal Diseases

RESULTS

HD and CKD groups had significantly higher endocan levels when compared with control group (median (IQR): 519.0 (202.3-742.0) versus 409.0 (245.3-505.3) and 273.0 (168.0-395.5) ng/L, respectively). Also, HD patients had significantly higher endocan levels when compared with CKD levels. HD patients had significantly higher carotid intima-media thickness (CIMT) when compared with CKD patients (median (IQR): 0.80 (0.80-0.90) versus 0.75 (0.73-0.75) mm, p < 0.001). HD patients had significantly higher frequency of SCA when compared with CKD patients (46.7% versus 13.3%, p=0.005). Patients with SCA had significantly higher hsCRP (median (IQR): 36.5 (26.8-43.5) versus 24.0 (15.8-29.0) mg/dl) and endocan levels (697.0 (528.3-974.8) versus 222.5 (158.8-565.8) ng/L) when compared with patients without SCA. ROC curve analysis of endocan for identification of SCA in HD patients showed that at a cutoff of 380.5 ng/L, endocan has an AUC of 0.862 with a sensitivity and specificity of 92.9% and 68.7%, respectively.

CONCLUSIONS

Serum endocan levels are related to SCA in HD patients. In addition, it is associated with the hyperinflammatory state in those patients.