Klotho gene is an anti-aging gene that is highly expressed in the kidney. Its encoding product Klotho protein can inhibit inflammation, oxidative stress injury, and apoptosis in renal tissue. It is regarded as a renal protective protein and expected to be a new target for the treatment of renal diseases. This article reviewed the biological characteristics of Klotho and the protective effect of Klotho on renal graft function.

Objective To study the prognostic role of plasma neutrophil gelatinase-associated lipocalin (NGAL) early after renal transplantation.Methods A total of 37 kidney recipients were enrolled from Department of Organ Transplantation,Guangdong Second Provincial General Hospital within a 12-month period of time.Plasma NGAL was measured immediately before and at 6 and 12 h post-transplantation.Changes of serum creatinine were documented daily within the first week postoperation.Acute kidney injury (AKI)/graft rejection during the first week after transplantation was the outcome variable.Results The levels of serum NGAL in the 37 patients were (311.14 ± 102.69),(317.81 ± 107.28) and (312.16 ± 134.80) μg/L respectively immediately before and at 6 and 12 h post-transplantation.There was no significant difference in serum NGAL levels before and 6 h or 12 h after operation (P =0.70,and P =0.96).There were no significant differences in gender and age between the two groups (P =0.29,and P =0.20).There was significant difference in creatinine levels between the AKI group and the non-AKI group (P =0.002) and between pre-operation and 6 or 12 h postoperation.The preoperative levels of serum NGAL in AKI group and non-AKI group were (333.58 ± 116.30) and (300.36 ± 96.15) μg/L (P =0.36),and those were (383.3 ± 147.16) and (286.32 ± 65.97) μg/L (P＜0.01) at 6 h,and (437.33 ± 164.16) and (252.08 ± 57.53) μg/L (P＜ 0.001) at 12 h after operation.The sensitivity and specificity of serumNGAL (317μg/L at 12 h after operation as the cutoff value) predicting AKI was 100％ and 92％ respectively,which was much better than that of serum creatinine at the corresponding time point (sensitivity =66.7％,and specificity =61.9％).Conclusion Plasma NGAL,particularly at 12 h after transplantation,is a very sensitive and specific biomarker for predicting AKI.

Objective To explore the feasibility of serum Klotho level in the elderly donors to predict the renal graft function in the recipients. Methods Clinical data of 16 elderly donors and 27 recipients undergoing renal transplantation were collected. The general status of the recipients was observed. The levels of serum Klotho and serum creatinine (Scr) in the elderly donors were measured on the day of renal transplantation. The Scr levels in the recipients were measured at postoperative 1, 3 and 12 months respectively. The estimated glomerular filtration rate (eGFR) was calculated. The correlation between the serum Klotho level of the donors and postoperative graft function of the recipients was analyzed. Results The cold ischemia time during renal transplantation was (649±245) min. The incidence rate of delayed graft function (DGF) was 26%. The incidence rate of acute rejection was 7%. In the elderly donors, the serum Klotho level was 537 (245-793) pg/mL and the Scr level was (164±62) μmol/L. At postoperative 1, 3 and 12 months, the Scr levels in the recipients were (136±47), (132±43) and (133±46) μmol/L, respectively. The corresponding eGFR was (52±20), (52±19) and (53±21) mL/(min?1.73m²), respectively. The serum Klotho level in the elderly donors was negatively correlated with the renal graft function at postoperative 1 month in the recipients (P < 0.05). The sensitivity and specificity of serum Klotho level in predicting the renal graft insufficiency at postoperative 1 month were 0.909 and 0.769. Conclusions The preoperative serum Klotho level in the elderly donors have predictive value for renal graft function in the recipients at postoperative 1 month.