Renal biomarkers for assessment of kidney function in renal transplant recipients: how do they compare?

Uncover diagnostic immunity/hypoxia/ferroptosis/epithelial mesenchymal transformation-related CCR5, CD86, CD8A, ITGAM, and PTPRC in kidney transplantation patients with allograft rejection

The aim of this study was to identify predictive immunity/hypoxia/ferroptosis/epithelial mesenchymal transformation (EMT)-related biomarkers, pathways and new drugs in allograft rejection in kidney transplant patients. First, gene expression data were downloaded followed by identification of differentially expressed genes (DEGs), weighted gene co-expression network analysis (WGCNA) and protein–protein interaction (PPI) analysis. Second, diagnostic model was construction based on key genes, followed by correlation analysis between immune/hypoxia/ferroptosis/EMT and key diagnostic genes. Finally, drug prediction of diagnostic key genes was carried out. Five diagnostic genes were further identified, including CCR5, CD86, CD8A, ITGAM, and PTPRC, which were positively correlated with allograft rejection after the kidney transplant. Highly infiltrated immune cells, highly expression of hypoxia-related genes and activated status of EMT were significantly positively correlated with five diagnostic genes. Interestingly, suppressors of ferroptosis (SOFs) and drivers of ferroptosis (DOFs) showed a complex regulatory relationship between ferroptosis and five diagnostic genes. CD86, CCR5, and ITGAM were respectively drug target of ABATACEPT, MARAVIROC, and CLARITHROMYCIN. PTPRC was drug target of both PREDNISONE and EPOETIN BETA. In conclusion, the study could be useful in understanding changes in the microenvironment within transplantation, which may promote or sustain the development of allograft rejection after kidney transplantation.

A urine score for noninvasive accurate diagnosis and prediction of kidney transplant rejection

Accurate and noninvasive monitoring of renal allograft posttransplant is essential for early detection of acute rejection (AR) and to affect the long-term survival of the transplant. We present the development and validation of a noninvasive, spot urine-based diagnostic assay based on measurements of six urinary DNA, protein, and metabolic biomarkers. The performance of this assay for detecting kidney injury in both native kidneys and renal allografts is presented on a cohort of 601 distinct urine samples. The urinary composite score enables diagnosis of AR, with a receiver-operator characteristic curve area under the curve of 0.99 and an accuracy of 96%. In addition, we demonstrate the clinical utility of this assay for predicting AR before a rise in the serum creatinine, enabling earlier detection of rejection than currently possible by standard of care tests. This noninvasive, sensitive, and quantitative approach is a robust and informative method for the rapid and routine monitoring of renal allografts.

Effect of deflazacort on pregnancy outcome in kidney transplant patients: should we change the immunosuppressant before conception?

Background

Despite the good prognosis in patients with transplant organs, limited evidence is available on how immunosuppressants affect pregnancy. The aim of this study was to determine whether immunosuppressant use affects the pregnancy outcome and to identify whether there is any need to change the immunosuppressant before the patient tries to conceive.

Methods

This retrospective cohort study included women with previous kidney transplantation history who visited the Department of Obstetrics and Gynecology for either infertility or antenatal care between January 2005 and May 2016. A total of 40 cases (36 women) met the inclusion criteria. Statistical analyses were performed using SAS version 9.4.

Results

There were no differences in the immunosuppressant regimen between the pregnant and non-pregnant groups (never-pregnant+miscarriage) (P = 0.73). Individual immunosuppressant use was significantly different in terms of pregnancy outcome among the never-pregnant, miscarriage, and clinical pregnancy groups (azathioprine, P = 0.01; deflazacort, P < 0.0001). Only deflazacort use differed significantly between the clinical pregnancy and non-pregnant groups (P = 0.003). After adjusting for factors that may affect pregnancy outcome, deflazacort use remained significantly associated with a decreased odds ratio for clinical pregnancy (P = 0.02). Cox regression analysis also showed that deflazacort use was the only remaining factor that could hinder the success of clinical pregnancy (P = 0.03).

Conclusions

Our study suggests that the type of immunosuppressive regimen may not affect the success of clinical pregnancy. However, deflazacort may decrease the possibility of clinical pregnancy in women with kidney transplant when they try to conceive.

First Canadian experience with robotic laparoendoscopic single-site vs. standard laparoscopic living-donor nephrectomy: A prospective comparative study

INTRODUCTION

We aimed to compare the outcomes of robotic laparoendoscopic single-site living donor nephrectomy (R-LESS LDN) vs. standard laparoscopic living donor nephrectomy (LLDN).

METHODS

Between October 2013 and November 2015, 39 patients were allocated to either standard LLDN (n=25) or R-LESS LDN (n=14). Patient demographics, perioperative outcomes, analgesic requirement, visual analogue scale of pain at postoperative days 1, 3, 7, and 30, and a health-related quality of life and body image questionnaire were prospectively collected.

RESULTS

There were no significant differences in demographics and intraoperative outcomes between the two cohorts. The R-LESS LDN cohort had lower analgesic requirement (p=0.002) and lower visual pain scores on days 1 and 3 (p=0.001). Additionally, body image and satisfaction scores in the R-LESS group were also superior compared to the LLDN cohort (p=0.008). There was no significant difference in the postoperative complications according to the Clavien-Dindo system. Recipient graft functional outcomes were equivalent.

CONCLUSIONS

This is the first evidence that R-LESS LDN is safe and associated with comparable surgical and early functional outcomes compared to LLDN, while pain, donor body image, and satisfaction scores were improved compared to LLDN.

Effect of glomerular filtration rate impairment on diagnostic performance of neutrophil gelatinase-associated lipocalin and B-type natriuretic peptide as markers of acute cardiac and renal failure in chronic kidney disease patients

INTRODUCTION

Cardio-renal syndromes are characterized by the impairment of cardiac and renal functions. Plasma and urinary neutrophil gelatinase-associated lipocalin (NGAL), and plasma B-type natriuretic peptide (BNP) are markers of acute kidney injury (AKI) and heart failure (HF), respectively.

METHODS

GFR (99mTc-DTPA), plasma BNP, and plasma and urinary concentrations of NGAL were measured in 310 clinically stable CKD patients, at functional stages from 1 to 5. Serum and urinary low-molecular-weight proteins cystatin C and β2-microglobulin, and urinary tubular enzymes were measured for comparison. Plasma BNP, NGAL, cystatin C and β2-microglobulin were measured also in 31 maintenance hemodialysis patients.

RESULTS

Plasma NGAL increased with the reduction of GFR in CKD patients from stage 2. In the different CKD stages modest differences were found for BNP values. Urinary NGAL increased slightly but significantly in patients at CKD stages 4 and 5, similarly to urinary cystatin C and β2-microglobulin. In maintenance hemodialysis patients, plasma NGAL and BNP were markedly increased, and high-flux hemodialysis significantly decreased their plasma concentrations.

CONCLUSIONS

Plasma NGAL increases markedly with the reduction in GFR, generating a very high number of false positive diagnoses of AKI in stable CKD patients. The grade of GFR impairment and the cause of kidney disease have a lower effect on urinary NGAL and on plasma BNP. In any case, specific reference values of NGAL and BNP should be used in chronic kidney disease patients, according to their functional stage, when assessing acute kidney injury, heart failure, and cardio-renal syndromes in patients with impaired GFR.

Cystatin C and serum creatinine as predictors of kidney graft outcome

PURPOSE

Serum cystatin C (Cys C) was evaluated as a predictor of kidney graft failure progression, and its predictive ability was compared to other markers of graft function.

METHODS

The following kidney graft markers were determined in 91 patients who came for regular checkups of kidney graft function to our outpatient service in February 2008: Cys C, serum creatinine (sCr), 24-h proteinuria and 24-h urinary creatinine clearance (CCr). Glomerular filtration rate (eGFR) was estimated using sCr-based and Cys C formula. Patients were regularly monitored until February 2013 or to graft failure.

RESULTS

During follow-up, graft failure occurred in 21 recipients. The Cys C ≥2.65 mg/l discriminated patients with and without graft failure (sensitivity of 80.95% and specificity of 92.86%). According to c statistic, the highest performance was achieved for Cys C (0.874). In addition, Cys C area under the curve (AUC) was significantly better than CCr AUC (p = 0.007), 24-h proteinuria AUC (p = 0.03), eGFR estimated by the chronic kidney disease epidemiology collaboration (EPI) AUC (p = 0.05), but not better than sCr or eGFR AUCs calculated by other formulas. In the multivariable model, sCr, CCr, Cys C and eGFRs were predictors of graft failure. Combination of Cys C, sCr and logarithm of 24 h proteinuria (0.883) or Cys C, CCr and logarithm of 24-h proteinuria (0.884) had the highest AUC for predicting graft outcome that exceed insignificantly Cys C or sCr areas.

CONCLUSIONS

The most reliable predictors of graft outcome were Cys C, sCr and proteinuria. Because Cys C is unavailable in many transplant centers, from the practical point of view, sCr remains the most sensitive predictor of graft outcome.

Evaluation of methods based on creatinine and cystatin C to estimate glomerular filtration rate in chronic kidney disease

PURPOSE

Estimated glomerular filtration rate (GFR) is a useful tool for the detection of chronic kidney disease (CKD). Several methods have been proposed, but findings can vary in specific groups such as patients with diabetes, elderly and high and low body mass index and, also, with the stage of CKD. The objective of this study was comparing the accuracy of the currently used equations for estimating GFR with that of the gold standard technetium-(99m)-diethylene triamine pentaacetic acid (99mTc-DTPA).

METHODS

We performed a cross-sectional study of 129 patients with all five CKD stages. GFR was estimated using the following: 24-h urine creatinine clearance, Cockcroft-Gault equation, MDRD equation, CKD-EPI equation, Hoek's cystatin C equation, and isotopic 99mTc-DTPA (as gold standard). We evaluated agreement in the whole study population and according to age, sex, weight, and diabetes.

RESULTS

All methods had good agreement. The best agreement was observed with the cystatin C [intraclass coefficient correlation (ICC) 95 % confidence interval (95 % CI), 0.87 (0.82-0.91)], followed by CKD-EPI [ICC 0.83 (0.77-0.88)]. Twenty-four-hour urine creatinine clearance showed the worst agreement in patients older than 65 years [ICC 0.70 (0.56-0.79)]. The Cockcroft-Gault equation showed the worst agreement in younger than 65 years [ICC 0.64 (0.42-0.79)]. The best agreement for classification in the correct CKD stage was with the cystatin C equation [κ = 0.80 (0.74-0.87)]. GFR was overestimated with all methods in CKD stages 4 and 5.

CONCLUSIONS

The methods used in clinical practice are adequate for classification of CKD. Cystatin C is the most accurate method, followed by CKD-EPI. The Cockcroft-Gault equation is not accurate in young patients. Twenty-four-hour urine creatinine clearance loses accuracy in patients aged older than 65 years.