Serum and spent dialysis fluid concentration of Neutrophil Gelatinase-Associated Lipocalin (NGAL) in patient with peritonitis

Abstract

Objective: Neutrophil gelatinase-associated lipocalin (NGAL) is a 25-kDa glycoprotein that is highly inducible in a variety of epithelial cells during inflammation. In the present study, we examined level of NGAL in serum and spent peritoneal dialysis fluid (sPDF) from patients with peritonitis (P). Methods: Serum and sPDF were collected from patients as baseline before the onset of P. Once patients developed P, serum was collected on days 1, 7, and 42 whereas sPDF were collected on days 1, 3, 5, 7, and 14 after P. The concentrations of NGAL in serum and sPDF were determined by sandwich ELISA. Results: Serum NGAL concentration collected from patients on day 1 after P was significantly higher (p<0.01) than baseline. There was no significant difference in serum NGAL concentration among serum collected at baseline and that of day 7 and day 42 after P. There was positive correlation (p<0.05) between neutrophil count and serum NGAL concentration at all time points after P examined suggesting that neutrophils are the source of the raised circulatory NGAL levels after P. NGAL concentration in sPDF remained significantly higher (p<0.05) than baseline at the first 3 days after the P episode and was gradually decreased from day 5 onward. There was positive correlation (p<0.05) between NGAL concentration in PDF of P patients and the neutrophil count on days 1 and 3, but not on days 5, 7, 14, or 42 after P, suggesting neutrophils are the source of the raised NGAL levels in the PDF only in the first 3 day after P. There was no difference in NGAL concentration in the serum or sPDF between patients with gram-negative and gram-positive bacterial P. However, the NGAL concentration in sPDF from patient with culture-negative P was significantly lower than that from patients with gram-negative and gram-positive bacterial P. Conclusion: We have provided novel data on the concentration of NGAL in serum and spent PDF from patients with P. We hope these data can help in future elucidation of the role of NGAL in P.