Levels of cystatin C in low- and high-flux hemodialysis in children with end-stage renal disease.

BACKGROUND: Cystatin-C (CyC) is a middle molecule that is freely filtered at the glomerulus and almost completely reabsorbed by the proximal tubules. The aim of this study was to evaluate serum CyC and its reduction ratio as a biomarker for assessing the adequacy of the hemodialysis (HD) sessions in children with end-stage renal disease on maintenance HD. We also compared levels of CyC in patients on low-flux HD (LFH) and high-flux HD (HFH). METHODS: Forty patients were included in the study and divided into two groups, with one group (16 patients) receiving HFH and the other group receiving LFH (24 patients) (high-flux and low-flux polysulfone filters, respectively). Before and after each dialysis session serum CyC and beta-2-microglobulin (B2M) levels were measured using an ELISA technique, and routine laboratory tests were performed for each patient. RESULTS: Pre-dialytic levels of CyC were significantly lower in the patients receiving HFH than in those receiving LFH (7.33 ± 1.35 vs. 9.73 ± 0.93, respectively; p < 0.0001). In the HFH group, post-dialytic levels of serum CyC were significantly lower than pre-dialytic levels (4.49 ± 0.71 vs. 7.33 ± 1.35, respectively; p < 0.0001). The reduction ratio (RR) of CyC was significantly higher in the HFH group than in the LFH group (38.2 ± 3.91 vs. -6.49 ± 5.05, respectively; p < 0.0001). Serum CyC level significantly correlated with B2M, urea and creatinine levels in both the LFH and HFH groups, whereas its RR significantly correlated with the RRs of urea, creatinine, and B2M in the HFH group. CONCLUSION: The results of our study emphasize the role of CyC as a good marker for assessing the adequacy of HD sessions in children on HFH and show that the CyC RR may be used as an index of middle-molecule toxin clearance following HFH sessions.

A comparative study of two angiogenic factors: vascular endothelial growth factor and angiogenin in induced sputum from asthmatic children in acute attack.

BACKGROUND: Angiogenesis is a prerequisite for airway remodeling in bronchial asthma. Several factors may play important roles in inflammation and angiogenesis through effects on inflammatory cell infiltration or neovascularization. OBJECTIVES: (1) To determine the levels of vascular endothelial growth factor (VEGF) and angiogenin in sputum supernatants of asthmatic children during the acute attack and 6 weeks after start of therapy; and (2) to correlate their levels with the degree of asthma severity. SUBJECTS AND METHODS: Twenty asthmatic children with acute attack (mean age, 9.6 +/- 3.5 years [+/- SD]) and 12 sex- and age-matched healthy control children were enrolled in the study. Sputum supernatants were collected for determination of VEGF and angiogenin levels. Serum samples were withdrawn for IgE measurement. The above tests were performed using an enzyme-linked immunosorbent assay. The FEV1 was measured using spirometry. VEGF, angiogenin, and FEV1 estimations were repeated for asthmatic children 6 weeks after start of therapy. RESULTS: During the acute attack, asthmatic children had significantly higher levels of VEGF and angiogenin than in healthy control children (p < 0.001). VEGF and angiogenin levels showed more elevation with increase in asthma severity (p < 0.001). A significant positive correlation existed between both angiogenic factors (r = 0.98, p < 0.001). A negative significant correlation was found between FEV1 percentage of predicted and both VEGF (r = -0.99, p < 0.001) and angiogenin (r = -0.97, p < 0.001). A nonsignificant correlation was found between serum IgE and sputum VEGF (r = 0.09, p > 0.05). Although there was a significant decrease in the levels of both VEGF and angiogenin after 6 weeks of treatment with corticosteroid inhalation therapy, the levels did not reach normal control levels (p < 0.001 and p < 0.05, respectively). CONCLUSIONS: Our results show that both VEGF and angiogenin levels were elevated in children with acute asthma. The study also suggests that increased severity of bronchial asthma in children is associated with the expression of both angiogenic factors, which are implicated in asthma pathogenesis. After 6 weeks of therapy, the levels of both angiogenic factors showed significant decrease.

Plasma neutrophil gelatinase-associated lipocalin as an early biomarker for prediction of acute kidney injury after cardio-pulmonary bypass in pediatric cardiac surgery.

INTRODUCTION: Cardiopulmonary bypass (CPB) surgery is considered one of the most frequent surgical procedures in which acute kidney injury (AKI) represents a frequent and serious complication. The aim of the present study was to evaluate the efficiency of neutrophil gelatinase-associated lipocalin (NGAL) as an early AKI biomarker after CPB in pediatric cardiac surgery. MATERIAL AND METHODS: The study included forty children aged 2 to 78 months undergoing CPB. They were divided into group I: patients who suffered AKI grades II and III; and group II: patients who did not develop AKI or at risk. Peripheral venous blood was withdrawn pre- and post-operatively for serial measurements of NGAL and creatinine. Statistical analysis was performed using Statistical Package for Social Sciences version 14. RESULTS: Mean plasma NGAL levels showed highly significant elevations in group I patients at 2, 12, and 24 h after surgery (p < 0.0001) compared to group II. Significant correlations were found between NGAL and creatinine at different time intervals. Highly significant correlations (p < 0.0001) were found between plasma NGAL and AKI at 2, 12 and 24 h after surgery. A cut-off level of 100 ng/ml at 2 h, and 125 ng/ml at 12 h post-operatively both recorded the highest accuracy, being 95% accurate, with sensitivity of 100% and 89.5% respectively, and specificity of 90.5% and 100% respectively. CONCLUSIONS: This study showed that plasma NGAL could be used as an early biomarker for detection of AKI following CPB. We recommend further studies on a wider scale to validate the current study results.