Predicting the ideal serum creatinine of kidney transplant recipients by a simple formula based on the balance between metabolic demands of recipients and renal mass supply from donors

Kidney Allograft Fibrosis: Diagnostic and Therapeutic Strategies

Interstitial fibrosis with tubule atrophy (IF/TA) is the response to virtually any sustained kidney injury and correlates inversely with kidney function and allograft survival. IF/TA is driven by various pathways that include hypoxia, renin-angiotensin-aldosterone system, transforming growth factor (TGF)-β signaling, cellular rejection, inflammation and others. In this review we will focus on key pathways in the progress of renal fibrosis, diagnosis and therapy of allograft fibrosis. This review discusses the role and origin of myofibroblasts as matrix producing cells and therapeutic targets in renal fibrosis with a particular focus on renal allografts. We summarize current trends to use multi-omic approaches to identify new biomarkers for IF/TA detection and to predict allograft survival. Furthermore, we review current imaging strategies that might help to identify and follow-up IF/TA complementary or as alternative to invasive biopsies. We further discuss current clinical trials and therapeutic strategies to treat kidney fibrosis.Supplemental Visual Abstract; http://links.lww.com/TP/C141.

[The impact of obesity on renal function at one year after kidney transplantation: single-center experience]

INTRODUCTION

Kidney transplantation is the treatment of choice for ESRD. Several studies have investigated the factors that may affect kidney function at 1 year. The factors mentioned are anemia, hypercholesterolemia, immunosuppressors, etc. We studied the independent predictors of serum creatinine>100μmol/L at 1 year.

MATERIALS AND METHODS

We conducted a retrospective study from March 1999 to December 2009. We conducted a chart review of 402 kidney transplant patients. The kidneys were removed from cadaveric donors. Data collected included age, weight, height, preoperative BMI, the causal nephropathy, smoking, hypertension, diabetes, anticoagulation. Intraoperative data included operative time, and cold ischemia. Statistical analysis consisted of a t-test for independent samples comparing the group with a creatinine≤100μmol/L vs>100 group, and univariate and multivariate Cox regression for a serum creatinine>100μmol/L at 1 year and test of correlation between BMI and serum creatinine at 1 year postoperatively.

RESULTS

We found a significant difference in BMI and cold ischemia with P=0.008 and P=0.002, respectively. In contrast there was no difference in age, operative time and blood loss, P=0.758, P=0.941 and P=0.963, respectively. Multivariate Cox regression showed that donor age P=0.004 (HR: 1.016 and CI: 1.005-1.027), a recipient age P=0.023 (HR: 0.986 and CI: 0.974-0.998) and BMI P=0.001 (HR: 1.019 and CI: 1.010-1.028) were independent predictors of serum creatinine>100μmol/L at 1 year. The Pearson correlation coefficient r=0.154 (P=0.004) showed a significant correlation between BMI and serum creatinine.

CONCLUSION

Our study showed that donor age, recipient age and BMI were independent predictors of renal function>100μmol/L at 1 year. Our results highlight the difficulty of the management of obesity in renal transplant patients.

LEVEL OF EVIDENCE

5.

Body weight difference between donor and recipient is an important affector of early graft function after renal transplantation

BACKGROUND

Poor early graft function (EGF), a frequent complication of kidney transplantation, can be caused by many risk factors, including donor kidney and body weights.

METHODS

We studied the relationship to early graft function in a rat kidney transplantation model among 3 indices: ratio of graft to body weight; ratio of native kidney to body weight, and weight difference/body weight of the recipient. We categorized 2 groups based on contralateral nephrectomy at day 1 (G1) or day 3 (G2) after transplantation. EGF was evaluated by measuring serum creatinine levels at day 1 after bilateral nephrectomy.

RESULTS

The 3 indices, ie, weight difference/body weight of recipient (G1 and G2: P < .0001), ratio of native kidney to body weight (G1: P < .0001; G2: P = .0013), and ratio of graft to body weight (G1: P = .0064; G2: P = .014) strongly correlated with EGF regardless of the time of contralateral nephrectomy.

CONCLUSIONS

The index of weight difference/body weight of recipient sensitively and predominantly influenced EGF, which probably reflects the systemic metabolic profile.

Assessment of kidney organ quality and prediction of outcome at time of transplantation

The critical importance of donor organ quality, i.e., number of surviving nephrons, ability to withstand injury, and capacity for repair in determining short- and long-term outcomes is becoming increasingly clear. This review provides an overview of studies to assess donor kidney quality and subsequent transplant outcomes based on clinical pathology and transcriptome-based variables available at time of transplantation. Prediction scores using clinical variables function when applied to large data sets but perform poorly for the individual patient. Histopathology findings in pre-implantation or post-reperfusion biopsies help to assess structural integrity of the donor kidney, provide information on pre-existing donor disease, and can serve as a baseline for tracking changes over time. However, more validated approaches of analysis and prospective studies are needed to reduce the number of discarded organs, improve allocation, and allow prediction of outcomes. Molecular profiling detects changes not seen by morphology or captured by clinical markers. In particular, molecular profiles provide a quantitative measurement of inflammatory burden or immune activation and reflect coordinated changes in pathways associated with injury and repair. However, description of transcriptome patterns is not an end in itself. The identification of predictive gene sets and the application to an individualized patient management needs the integration of clinical and pathology-based variables, as well as more objective reference markers of transplant function, post-transplant events, and long-term outcomes.