Increased total cytokeratin-18 serum and urine levels in chronic kidney disease

Abstract

Background Increased cell death in chronic kidney disease (CKD) by either necrosis or apoptosis has been confirmed by a variety of studies. Possible sources are an inadequate persistent inflammation and ischemia as a consequence of CKD or caused by the underlying renal disease. Detection of total or caspase cleaved cytokeratin 18 (CK-18) is a novel and elegant method to determine necrosis or apoptosis of epithelial cells in the patients' sera and urine. Methods 120 patients with CKD stages 1 to 5 were included in the study. Twenty healthy volunteers served as controls. Total and caspase cleaved CK-18 urine and serum concentrations were determined by ELISA. Results The concentration of serum total CK-18 was significantly higher in CKD stages 3–5 as compared to the healthy controls. Urinary total CK-18 excretion was increased in patients with CKD 5 compared to controls. A significant correlation between urine total CK18 and urine protein and albumin levels was found. Moreover, ROC curve analysis showed the potential of serum and especially urine total CK-18 levels to predict various CKD stages. Conclusions We provide evidence for increased total CK-18 serum and urine levels in CKD patients, possibly indicating that epithelial cell necrosis is prevalent in CKD.