| Objective: To investigate the time course of serum and urine Klothoconcerntration in patients pre and after cardiac sugery. To evaluate the relationship ofserum and urine Klotho concentration with the development and the prognosis ofacute kidney injury after cardiac surgery.Methods:1) Patients undergoing cardiac surgery were enrolled in thisprospective study. Patients’ serum and urine were collected on different timepointsbefore and after surgery. The demographics, laboratory parameters and prognosisconditions of patients were also recorded. The concentration of Klotho protein in theirurine and serum was detected by ELISA. Klotho protein concentrations on differenttimepoints were compared between AKI patients and non-AKI patients. Theconcentration of Klotho protein in urine was compared with the NGAL’s. Risk factorsof AKI following cardiac surgery were analysed using multiple-stepwise logisticregression analysis.2) The concentration of Klotho protein in urine and serum werecompared in patients with different outcomes.The risk factors of the outcome of AKIwere analysed by the logistic regression. Thus the relationship between Klotho proteinconcentration and the prognosis of patients was explored.Results:1)91patients following cardiac surgery were enrolled.The average agewas61.08±9.69years old with63.7%of male,15.4%of diabetics mellitus (DM) and36.3%of hypertension (HBP). There were33patients who developed AKI. Thedemographics of AKI and non-AKI patients were similar. The operation duration andCPB duration of AKI patients were longer than that of non-AKI (all P<0.05). Thepreoperative Cystatin C of AKI patients was higher than that of non-AKI patients(P<0.05). At the same time, the length of stay of AKI patients was longer than that ofnon-AKI patients, the hospitalization costs of AKI patients was higher than that of non-AKI patients (P<0.05).2)The preoperative Klotho protein concentration in urineand serum of AKI patients was similar to that of non-AKI patients (P>0.05). Thedescend range of Klotho concentration in serum of AKI patients was significantlyhigher than that of non-AKI patients at0hr after surgery (0.177±0.155vs0.456±0.327ng/mL, P<0.05). The ascensional range of Klotho concentration in urine of AKIpatients was significantly higher than that of non-AKI patients at0hr after surgery[1.690(1.026,2.677)vs0.526(0.230,0.891) ng/μmol, P<0.05].3) Logistic regressionanalysis showed that longer operation duration, increased urinary Klothoconcentration and decreased serum Klotho concentration were the independent riskfactors of AKI events in patients following cardiac surgery.4) At0hr after surgery, theserum Klotho concentration in patients without totally recovery of renal function wassignificantly lower than that in serum of patients with totally recovery of renalfunction (P<0.05). The risk factors of the recovery of renal function in AKI patientswere the duration of cardiac arrest, the duration of aortic cross clamp, baseline eGFR,Klotho concentration in urine at0hr after surgery, Klotho concentration in serum at0hr after surgery.5) The diagnosis value of serum and urine Klotho for the incidenceof AKI immediately after surgery was good. The area under the receiver-operatingcharacteristic(ROC) curve of serum Klotho was0.788with the sensitivity of0.707and specificity of0.788for a cutoff value of0.234ng/mL. ROC of urine Klotho was0.853with the sensitivity of0.909and specificity of0.759for a cutoff value of0.858ng/μmol.Conclusion: Both urine and serum concentration of Klotho protein in patientsundergoing cardiac surgery changed immediately after surgery and extend for a longtime, which may be earlier than that of urine NGAL, suggesting Klotho may becomea biomaker in diagnosis of AKI. Longer operation time, increased urine Klothoconcentration and decreased serum Klotho concentration were the independent riskfactors of AKI events in patients after cardiac surgery. The decreased serum Klothoprotein may relate to the prognosis of AKI. |
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