Endothelium-related biomarkers enhanced prediction of kidney support therapy in critically ill patients with non-oliguric acute kidney injury.

Acute kidney injury (AKI) is a common condition in hospitalized patients who often requires kidney support therapy (KST). However, predicting the need for KST in critically ill patients remains challenging. This study aimed to analyze endothelium-related biomarkers as predictors of KST need in critically ill patients with stage 2 AKI. A prospective observational study was conducted on 127 adult ICU patients with stage 2 AKI by serum creatinine only. Endothelium-related biomarkers, including vascular cell adhesion protein-1 (VCAM-1), angiopoietin (AGPT) 1 and 2, and syndecan-1, were measured. Clinical parameters and outcomes were recorded. Logistic regression models, receiver operating characteristic (ROC) curves, continuous net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were used for analysis. Among the patients, 22 (17.2%) required KST within 72 h. AGPT2 and syndecan-1 levels were significantly greater in patients who progressed to the KST. Multivariate analysis revealed that AGPT2 and syndecan-1 were independently associated with the need for KST. The area under the ROC curve (AUC-ROC) for AGPT2 and syndecan-1 performed better than did the constructed clinical model in predicting KST. The combination of AGPT2 and syndecan-1 improved the discrimination capacity of predicting KST beyond that of the clinical model alone. Additionally, this combination improved the classification accuracy of the NRI and IDI. AGPT2 and syndecan-1 demonstrated predictive value for the need for KST in critically ill patients with stage 2 AKI. The combination of AGPT2 and syndecan-1 alone enhanced the predictive capacity of predicting KST beyond clinical variables alone. These findings may contribute to the early identification of patients who will benefit from KST and aid in the management of AKI in critically ill patients.

Angiopoietin-2: A Potential Mediator of the Glycocalyx Injury in Adult Nephrotic Patients.

INTRODUCTION: Glomerulopathy is a group of diseases that affect mainly young adults between the ages of 20 and 40 years. Recently, it has been demonstrated that syndecan-1, a biomarker of endothelial glycocalyx damage, is increased in nephrotic patients with near-normal renal function and it is important to endothelial dysfunction in these patients. Angiopoietin-2 (AGPT2) is an endothelial growth factor that promotes cell derangement. Here we evaluated AGPT2 levels in patients with nephrotic syndrome, near-normal renal function and the possible interaction of AGPT2 with endothelial glycocalyx derangement. METHODS: This was a cross-sectional study performed from January through November 2017. Adult patients (age > 18 years) with nephrotic syndrome and without immunosuppression were included. Blood samples were drawn after a 12 h fast for later measurement of syndecan-1 and AGPT2. Mediation analyses were performed to assess the hypothesized associations of nephrotic syndrome features and AGPT2 with syndecan-1. RESULTS: We included 65 patients, 37 (56.9%) of them female, with primary glomerular disease. Syndecan-1 in nephrotic patients was higher than in control individuals (102.8 ± 36.2 vs. 28.2 ± 9.8 ng/mL, p < 0.001). Correlation of syndecan-1 with the main features of nephrotic syndrome after adjustment for age and estmmated glomerular filtration rate (eGFR) demonstrated that syndecan-1 was significantly associated with 24-h urinary protein excretion, total cholesterol, LDL (low density lipoprotein)-cholesterol, HDL (high-density lipoprotein)-cholesterol, and triglycerides. Angiopoietin-2 was independently associated with serum albumin, 24 h urinary protein excretion, total cholesterol, and LDL-cholesterol, in addition to being strongly associated with syndecan-1 (0.461, p < 0.001). The results of the mediation analyses showed that the direct association between LDL-cholesterol and syndecan-1 was no longer significant after AGPT-2 was included in the mediation analysis. AGPT2 explained 56% of the total observed association between LDL-cholesterol and syndecan-1. CONCLUSION: The association between LDL-cholesterol and glycocalyx derangement in nephrotic patients is possibly mediated by AGPT2.

Glycocalyx injury in adults with nephrotic syndrome: Association with endothelial function.

BACKGROUND: Glomerulopathy is a group of diseases that affect mainly young adults. Endothelial dysfunction, atherosclerosis, and increased cardiac mortality can complicate the evolution of such patients. However, there is no study evaluating endothelial glycocalyx in this pathology. METHODS: This cross-sectional study included 49 patients with untreated primary nephrotic syndrome that were otherwise healthy. In addition to routine laboratory measurements, syndecan-1, intercellular adhesion molecule-1 (ICAM-1), and e-selectin were measured. Moreover, flow-mediated dilation (FMD) was used as the main endothelial function surrogate. RESULTS: Of the 49 patients with nephrotic syndrome, 25 (51.0%) were females. The mean age of patients was 39.0±12.1y. FMD was reduced in nephrotic patients in comparison with controls (3.7±1.7 vs. 6.6±1.1%, p<0.001). Nephrotic patients had higher levels of ICAM-1 (616.6±219.7 vs. 356.9±102.0ng/ml, p<0.001) and syndecan-1 (180.3±64.1 vs. 28.2±9.8ng/ml, p<0.001). No significant difference was observed regarding e-selectin (129.9±54.2 vs. 120.2±61.5ng/ml, p=0.489). After adjusting for age and glomerular filtration rate, syndecan-1 was significantly associated with 24-h urinary protein excretion, LDL-cholesterol, HDL-cholesterol, and triglycerides. While age, LDL-cholesterol, and 24-h urinary protein excretion were associated with FMD in the multivariate analysis, when syndecan-1, ICAM-1, and e-selectin were added to the model, only syndecan-1 was independently associated with FMD. CONCLUSIONS: We demonstrated that syndecan-1, a marker of endothelial glycocalyx damage, is increased in patients with nephrotic syndrome and near-normal renal function. Moreover, we determined its association with nephrotic syndrome features and suggest it can have a role in the endothelial dysfunction of these patients.