Assessing donor kidney function: the role of CIRBP in predicting delayed graft function post-transplant

Abstract

Introduction: Delayed graft function (DGF) shortens the survival time of transplanted kidneys and increases the risk of rejection. Current methods are inadequate in predicting DGF. More precise tools are required to assess kidney suitability for transplantation. Cold-inducible RNA-binding protein (CIRBP) expression has been linked to acute kidney injury, suggesting its potential as a new biomarker for transplanted kidney function.

Methods: We included deceased donors and recipients who had undergone successful kidney transplantation between 2016 and 2019. Recipients and their paired donors are assigned to either the DGF or immediate graft function (IGF) group, based on the recipient's recovery of graft renal function. Donor plasma CIRBP levels were measured using an enzyme-linked immunosorbent assay kit to assess their relationships with DGF.

Results: Donor plasma CIRBP concentrations in the DGF group were approximately twice as high as those in the IGF group (6.82 vs. 3.44; P<0.001). DGF occurred in all cases where CIRBP concentrations exceeded 7.92 ng/mL. Furthermore, univariate and multivariate analyses (odds ratio [OR]=1.660; P<0.001) confirmed that donor plasma CIRBP level was an independent risk factor for DGF. Additionally, higher CIRBP levels were associated with increased plasma creatinine at 6 months (R²=0.08; P<0.001), and survival analysis showed shorter kidney survival in recipients with DGF (P=0.002).

Conclusions: This study demonstrated that donor plasma CIRBP levels can effectively predict the occurrence of DGF. CIRBP is a potential novel biomarker for evaluating transplanted kidney function.

Clinical trial registration: https://clinicaltrials.gov, identifier NCT06641622.

Keywords: acute kidney injury; cold-inducible RNA binding protein; delayed graft function; graft survival; kidney transplantation.

Figure 1

Flow chart of kidney donors and recipients enrolled in the study.

Figure 2

(A) Donor terminal serum creatinine (SCr) levels were significantly elevated in the DGF group compared to the IGF group. (B) Donor plasma CIRBP concentrations were markedly higher in the DGF group than in the IGF group. (C) There was no statistically significant difference in KDPI values between the DGF and IGF groups. (D) The proportion of female recipients in the DGF group was significantly lower compared to the IGF group. Red dots indicate lost graft kidneys. ns, no significance; ***, P<0.001.

Figure 3

The receiver operating characteristic (ROC) curves depict the ability of donor characteristics to distinguish between immediate graft function (IGF) and delayed graft function (DGF). These curves include donor terminal serum creatinine (A), donor plasma CIRBP (B), kidney donor profile index (KDPI) (C), a prediction model incorporating donor plasma CIRBP and terminal serum creatinine (D), a prediction model incorporating donor plasma CIRBP and female recipient status (E), and a prediction model combining donor plasma CIRBP, female recipient status, and terminal serum creatinine (F).

Figure 4

Spearman correlation analysis between recipient serum creatinine levels at 6 months post-transplantation and donor plasma donor CIRBP (A), terminal serum creatinine (B), and KDPI (C).

Figure 5

(A) Graft survival analysis using Kaplan–Meier curves based on donor plasma CIRBP levels (> 5.484 ng/ml). (B) Graft survival analysis using Kaplan–Meier curves according to whether recipients developed DGF. ROC curves showing the performance of donor characteristics in distinguishing between graft survival and graft loss, including donor terminal serum creatinine (C), donor plasma CIRBP (D), and KDPI (E).