Urinary biomarkers after donor nephrectomy

Organ-Specific Monitoring of Solitary Kidney after Living Donation by Using Markers of Glomerular Filtration Rate and Urinary Proteins

BACKGROUND

Effective follow-up after living kidney donation is important for maintaining the renal function of the donor. We investigated whether the estimated glomerular filtration rate (eGFR) and urinary protein and enzyme levels can provide important information regarding the state of the remaining kidney after donor nephrectomy.

METHODS

Seventy-five living donations were included (prospective/retrospective) in the study. The following parameters were measured up to 1 year after donor nephrectomy: serum creatinine and cystatin C as markers of the GFR; the high-molecular-weight urinary proteins as markers of glomerular injury; and the low-molecular-weight urinary proteins and urinary enzymes as markers of tubular function.

RESULTS

One year after kidney donation, the creatinine and cystatin C values were 1.38-fold increased than their initial values, while the eGFR was 32% lower. At that time, 38% of donors had a moderate or high risk of CKD progression. The biochemical urinary glomerular and tubular kidney markers examined showed different behaviors. After a transient increase, the glomerular proteins normalized. Conversely, the detection of low-molecular-weight urinary proteins and enzymes reflected mild tubular damage at the end of the study period.

CONCLUSIONS

Our findings suggest that for the evaluation of mild tubular damage, low-molecular-weight marker proteins should be included in the urine diagnostic of a personalized living kidney donor follow-up.

Impact of Remote Ischemic Preconditioning Conducted in Living Kidney Donors on Renal Function in Donors and Recipients Following Living Donor Kidney Transplantation: A Randomized Clinical Trial

Although remote ischemic preconditioning (RIPC) has been shown to have renoprotective effects, few studies have assessed the effects of RIPC on renal function in living kidney donors. This study investigated whether RIPC performed in living kidney donors could improve residual renal function in donors and outcomes in recipients following kidney transplantation. The donors were randomized into a control group (n = 85) and a RIPC group (n = 85). The recipients were included according to the matched donors. Serum creatinine (sCr) concentrations and estimated glomerular filtration rate (eGFR) were compared between control and RIPC groups in donors and recipients. Delayed graft function, acute rejection, and graft failure within one year after transplantation were evaluated in recipients. sCr was significantly increased in the control group (mean, 1.13; 95% confidence interval (CI), 1.07–1.18) than the RIPC group (1.01; 95% CI, 0.95–1.07) (p = 0.003) at discharge. Donors with serum creatinine >1.4 mg/dL at discharge had higher prevalence of chronic kidney disease (n = 6, 26.1%) than donors with a normal serum creatinine level (n = 8, 5.4%) (p = 0.003) after one year. sCr concentrations and eGFR were similar in the RIPC and control groups of recipients over the one-year follow-up period. Among recipients, no outcome variables differed significantly in the RIPC and control groups. RIPC was effective in improving early renal function in kidney donors but did not improve renal function in recipients.

Prospective assessment of urinary neutrophil gelatinase-associated lipoprotein in living kidney donors: toward understanding differences between chronic kidney diseases of surgical and medical origin

OBJECTIVES

To evaluate the clinical implications of postoperative urinary neutrophil gelatinase-associated lipoprotein (NGAL) changes and the association between urinary NGAL (uNGAL) and renal function in living kidney donors.

SUBJECTS, PATIENTS AND METHODS

We included 76 healthy adults who underwent donor nephrectomy between December 2013 and November 2014. Perioperative serum creatinine (sCr), uNGAL, serum NGAL (sNGAL), and urinary microalbumin were prospectively measured until 6 months postoperatively. Patients with chronic kidney disease (CKD) due to medical disorders who visited our outpatient clinic during the same period were included for comparison.

RESULTS

The mean (SD) preoperative uNGAL of donors was 5 (5.17) ng/mL. uNGAL (corrected for urinary creatinine) was maximal at 1-2 days postoperatively, decreased on postoperative day 3, and stabilised by 7 days after surgery. Postoperative uNGAL was not associated with sex, age, or preoperative renal function. When corrected for sNGAL to compensate for the systemic increase in NGAL with major surgery, uNGAL on days 1-3 postoperatively was negatively correlated with sCr. Postoperatively, donor uNGAL remained higher than preoperatively for up to 6 months but was significantly lower than in patients with medical CKD with similar glomerular filtration rates.

CONCLUSION

Acute kidney injury due to hyperfiltration of remnant kidney after donor nephrectomy was maximal within 1-2 days postoperatively. The rise in uNGAL during this period in donors was negatively correlated with postoperative sCr levels. Decreased renal function after nephrectomy differs from that of medical CKD.

Cystatin-C is associated with partial recovery of kidney function and progression to chronic kidney disease in living kidney donors: Observational study

Donor nephrectomy in living-donor kidney transplantation may result in hyperfiltration injury in remnant kidney; however, its clinical implication in partial recovery of kidney function (PRKF) in remnant kidney and chronic kidney disease (CKD) progression remains unclear. Thus, we investigated the effect of PRKF on CKD development in the residual kidney and the utility of cystatin-C (Cys-C) in evaluating renal function in living-donor kidney transplantation donors.The electronic medical records and laboratory results of 1648 kidney transplant (KT) donors and 13,834 healthy nondonors between January 2006 and November 2014 were reviewed. The predictors of PRKF and CKD diagnosed by Kidney Disease: Improving Global Outcomes (KDIGO) criteria were evaluated by multivariate analysis. CKD risk was compared between KT donors and healthy nondonors using Cox proportional hazard regression analysis following propensity score matching (PSM).The incidence of PRKF for KT donors was 49.3% (813). CKD incidence was 24.8% (408) in KT donors and 2.0% (277) in healthy nondonors. The predictors of PRKF were, male sex (odds ratio [OR], 17.32; 95% confidence interval [CI] 9.16-32.77), age (OR, 1.02; 95% CI, 1.00-1.04; P < 0.001), Cys-C concentration (OR, 1.02; 95% CI, 1.00-1.04; P = 0.02), and preoperative albumin level (OR, 0.49; 95% CI, 0.27-0.89; P = 0.02). The predictors of CKD were age (hazards ratio [HR], 1.04; 95% CI, 1.02-1.05; P < 0.001), Cys-C concentration (HR, 1.024; 95% CI, 1.012-1.037; P < 0.001), and PRKF (HR, 1.41; 95% CI, 1.04-1.92; P = 0.03). After PSM, the risk of progression to CKD was higher in KT donors than in healthy nondonors (HR, 58.4; 95% CI, 34.2-99.8; P < 0.001).Donor nephrectomy is associated with PRKF and progression to CKD. Cys-C is a useful early marker for detecting PRKF and CKD.

Plasma Neutrophil Gelatinase-associated Lipoprotein in Living Kidney Donors

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker for acute kidney injury. This study was conducted to determine the clinical implications of perioperative plasma NGAL levels for renal function after living donor nephrectomy.

METHODS

Between July 2013 and May 2014, 112 donors underwent live donor nephrectomy at our institution. Donor plasma NGAL levels were measured perioperatively for 6 months. The relationship between perioperative plasma NGAL and recovery of renal function was analyzed. Renal function was estimated with the Modification of Diet in Renal Disease formula.

RESULTS

Mean preoperative NGAL was 62.1 ± 29.5 ng/mL. Plasma NGAL was most elevated 1 week postoperatively (218 ± 95.5 ng/mL), and stabilized after 1 month (122.9 ± 45.3 ng/mL). Preoperative plasma NGAL was not correlated with donor age or preoperative estimated glomerular filtration rates (eGFR), but was negatively correlated with 6-month eGFR (r = -0.458, P < .001). During the observation period, plasma NGAL at 1 week was most correlated with 6-month eGFR (r = -0.554, P < .001). An ROC curve analysis showed that age, preoperative eGFR, and 1-week postoperative plasma NGAL were highly predictive of developing of chronic kidney disease (CKD), defined as eGFR <60 mL/min/1.73 m(2), 6 months postoperatively (AUC = 0.91, P < .001). One-week postoperative plasma NGAL was also independently associated with CKD risk at 6 months (odds ratio: 1.13 for each 10 ng/mL increase, P = .013).

CONCLUSION

Plasma NGAL becomes elevated after kidney donation and can provide information about acute kidney injury during the compensatory hyperfiltration period. Donors with increased perioperative plasma NGAL require close observation because their possibility of developing CKD after donation may be greater.

Hand-assisted Laparoscopic Donor Nephrectomy and Cytokine Changes

BACKGROUND

Laparoscopic living-donor nephrectomy (LDN) exerts systemic effects causing transaminitis and increased urinary neutrophil gelatinase-associated lipocalm (NGAL) excretion. Hand-assisted laparoscopic donor nephrectomy, which tends to be shorter with less pneumoperitoneum, may be hypothesized to produce less systemic stimulation than total laparoscopic LDN.

METHODS

Serial urine and serum samples were collected from 15 patients undergoing HALDN. Samples were analyzed for NGAL and kidney injury molecule 1 (KIM-1) levels preoperatively and 24 hours post-surgery. Data relating to alanine aminotransferase, creatinine, and estimated glomerular filtration rate was also analyzed in 48 live donors preoperatively and at 24 hours and 48 hours post-surgery and compared to published data on LDN.

RESULTS

Expected changes to creatinine and estimated glomerular filtration rates were observed in the donors. Compared to the preoperative levels, alanine aminotransferase levels showed a significant decrease at 24 hours (P = .004) and were not significantly different from baseline levels at 48 hours (P = .08). Serum KIM-1 and NGAL levels remained unchanged (P = .89 and P = .14, respectively) at 24 hours after donation. Similarly, urinary levels of KIM-1 and NGAL were not statistically significantly different after donation. Mean operating time for this cohort was 1 hour, 36 minutes.

CONCLUSIONS

In contrast to other published data, our cohort did not exhibit changes to liver function tests or biomarker changes after donor nephrectomy. This could be because of the lower operative time (96 minutes vs. 216 minutes) or because of the intermittent release of the pneumoperitoneum in the hand-assisted method which may exert less of a systemic inflammatory response.