Kidney histology and function in liver transplant patients

[Kidney failure after liver transplantation]

One third of cirrhotic patients present impaired kidney function. It has multifactorial causes and has a harmful effect on patients' morbi-mortality before and after liver transplant. Kidney function does not improve in all patients after liver transplantation and liver-transplant recipients are at high risk of developing chronic kidney disease. Causes for renal dysfunction can be divided in three groups: preoperative, peroperative and postoperative factors. To date, there is no consensus for the modality of evaluation the risk for chronic kidney disease after liver transplantation, and for its prevention. In the present review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease to determine a risk stratification for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this setting, and highlight the indications of combined liver-kidney transplantation.

Kidney Failure after Liver Transplantation

One-third of patients with cirrhosis present kidney failure (AKI and CKD). It has multifactorial causes and a harmful effect on morbidity and mortality before and after liver transplantation. Kidney function does not improve in all patients after liver transplantation, and liver transplant recipients are at a high risk of developing chronic kidney disease. The causes of renal dysfunction can be divided into three groups: pre-operative, perioperative and post-operative factors. To date, there is no consensus on the modality to evaluate the risk of chronic kidney disease after liver transplantation, or for its prevention. In this narrative review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease in order to establish a risk categorization for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this context, and highlight the indications of combined liver–kidney transplantation.

Risk factors for new-onset chronic kidney disease in patients who have received a liver transplant

The aim of the present study was to analyze the risk factors for new-onset chronic kidney disease (CKD) in patients who have received a liver transplant. A total of 190 patients who underwent liver transplantation between March 2001 and January 2015 were followed up, and analyzed retrospectively. Sex, age, primary disease, preoperative laboratory findings (hemoglobin, albumin, creatinine and glomerular filtration rate), surgical approach, blood loss during the surgery and transfusion volume, postoperative complications, and the average levels of calcineurin inhibitors (CNIs) (from liver transplantation to the onset of CKD) were analyzed. In total, 40 patients developed new-onset CKD after transplantation. Clinical data in the new-onset CKD group were compared with the non-CKD group. A χ2 test, t-test and logistic regression analysis were performed using SPSS 17.0 software. The incidence of new-onset CKD after liver transplantation was 21.1%. Renal pathology included IgA nephropathy, hepatitis B virus-associated nephropathy, membranous proliferative glomerulonephritis, focal segmental glomerular sclerosis and cryoglobulinemia-associated renal injury. Among the CKD patients, 85.7% had tubulointerstitial damage. Univariate analysis showed that preoperative renal function, hemoglobin, intraoperative blood loss and transfusion volume, postoperative acute kidney injury, average levels of CNIs, and hypertension were risk factors for new-onset CKD after liver transplantation. Logistic regression analysis showed that preoperative glomerular filtration rate [odds ratio (OR)=0.980, P=0.041], hemoglobin (OR=0.972, P=0.034), average levels of CNIs (OR=1.364, P=0.015) and hypertension (OR=4.833, P=0.048)] were independent risk factors for new-onset CKD. The incidence of new-onset CKD in patients who received liver transplantation was high. The main risk factors were identified to be preoperative glomerular filtration rate, hemoglobin, postoperative average levels of CNIs and hypertension.

Pretransplant urinary proteome analysis does not predict development of chronic kidney disease after liver transplantation

BACKGROUND & AIMS

Chronic kidney disease (CKD) is a common complication after liver transplantation. Kidney biopsies cannot be easily performed before liver transplantation to predict patients at high risk for CKD. The aim of our study was to determine whether pre-, peri- and post-transplant factors, as well as peptides present in preliver transplant urine samples were associated with loss in kidney function at 6 months post-transplantation using proteome analysis.

METHODS

Eighty patients who underwent a liver transplantation and that had pretransplant glomerular filtration rate (GFR) value of ≥60 mL/min/1.73 m² (MDRD) were included in the study.

RESULTS

GFR decreased significantly after transplantation. At month 6 post-transplantation, 40 patients displayed a CKD, i.e. eGFR of <60 mL/min/1.73 m², while the other 40 patients did not. Although thousands of peptides were identified, none was significantly associated with the development of CKD at 6 months after liver transplantation. Moreover, using a urinary peptidome classifier to detect preexisting CKD, no difference was found in CKD scores between the 2 groups. After analysis of a large number of pre-, peri- and post-transplant parameters, viral hepatitis as a cause for liver transplantation was the sole independent predictive factor for CKD. No difference in peptides with differential urinary abundance between patients who received a graft for virus related liver disease vs. all other causes of liver disease was observed.

CONCLUSION

Urinary peptidome analysis before liver transplantation failed to identify a peptide pattern associated with the development of CKD at 6 months after liver transplantation.

Outcomes and native renal recovery following simultaneous liver-kidney transplantation

With the increase in patients having impaired renal function at liver transplant due to MELD, accurate predictors of posttransplant native renal recovery are needed to select candidates for simultaneous liver-kidney transplantation (SLK). Current UNOS guidelines rely on specific clinical criteria for SLK allocation. To examine these guidelines and other variables predicting nonrecovery, we analyzed 155 SLK recipients, focusing on a subset (n = 78) that had post-SLK native GFR (nGFR) determined by radionuclide renal scans. The 77 patients not having renal scans received a higher number of extended criteria donor organs and had worse posttransplant survival. Of the 78 renal scan patients, 31 met and 47 did not meet pre-SLK UNOS criteria. The UNOS criteria were more predictive than our institutional criteria for all nGFR recovery thresholds (20-40 mL/min), although at the most conservative cut-off (nGFR ≤ 20) it had low sensitivity (55.3%), specificity (75%), PPV (67.6%) and NPV (63.8%) for predicting post-SLK nonrecovery. On multivariate analysis, the only predictor of native renal nonrecovery (nGFR ≤ 20) was abnormal pre-SLK renal imaging (OR 3.85, CI 1.22-12.5). Our data support the need to refine SLK selection utilizing more definitive biomarkers and predictors of native renal recovery than current clinical criteria.

Proteinuria following sirolimus conversion is associated with deterioration of kidney function in liver transplant recipients

BACKGROUND

The role of sirolimus (SRL) conversion in the preservation of kidney function in liver transplant (LT) recipients with calcineurin inhibitor (CNI) nephrotoxicity is unclear.

METHODS

Data on 102 LT recipients with deteriorating kidney function after CNI exposure who were later converted to SRL were retrospectively reviewed. Kidney function was assessed using serum creatinine and estimated glomerular filtration rate (eGFR) at time of conversion and serially thereafter. The primary endpoint was stabilization or improvement of kidney function as assessed by eGFR at last recorded follow-up compared with eGFR at the time of conversion.

RESULT

After a median (interquartile range) of 3.1 (1.6-4.5) years of follow-up, serum creatinine decreased from 1.9 ± 0.8 to 1.8 ± 0.7 mg/dL (P=0.25) and eGFR increased from 40.8 ± 16.7 to 44.3 ± 20.0 mL/min (P=0.03). During the same time period, 24-hr urinary protein excretion increased from median (interquartile range) of 72 (0-155) to 382 (169-999) mg/day (P=0.0001). Sixty-five (64%) patients achieved the primary endpoint and 37 (36%) experienced deterioration in kidney function. Independent predictors of deterioration of kidney function after SRL conversion were development of proteinuria ≥ 1000 mg/day (odds ratio [OR]: 3.3, confidence interval [CI]: 1.1-9.5 P=0.03), post-LT diabetes (OR: 4.2, CI: 1.6-11.1, P=0.004), and higher eGFR at time of conversion (OR: 1.6, CI: 1.2-2.2, P=0.003).

CONCLUSION

Improvement or stabilization of kidney function occurred in the majority of LT recipients converted to SRL for CNI nephrotoxicity. Proteinuria ≥ 1000 mg/day, post-LT diabetes, and higher baseline eGFR were independent predictors of kidney function loss after SRL conversion.

Do kidney histology lesions predict long-term kidney function after liver transplantation?

Histological renal lesions observed after liver transplantation are complex, multifactorial, and interrelated. The aims of this study were to determine whether kidney lesions observed at five yr after liver transplantation can predict long-term kidney function. Ninety-nine liver transplant patients receiving calcineurin inhibitor (CNI)-based immunosuppression, who had undergone a kidney biopsy at 60±48 months post-transplant, were included in this follow-up study. Kidney biopsies were scored according to the Banff classification. Estimated glomerular filtration rate (eGFR) was assessed at last follow-up, that is, 109±48 months after liver transplantation. eGFR decreased from 92±33 mL/min at transplantation to 63±19 mL/min after six months, to 57±17 mL/min at the kidney biopsy, to 54±24 mL/min at last follow-up (p<0.0001). At last follow-up, only three patients required renal replacement therapy. After the kidney biopsy, 13 patients were converted from CNIs to mammalian target of rapamycin inhibitors, but no significant improvement in eGFR was observed after conversion. Elevated eGFR at six months post-transplant and a lower fibrous intimal thickening score (cv) observed at five yr post-transplant were the two independent predictive factors for eGFR≥60 mL/min at nine yr post-transplant. Long-term kidney function seems to be predicted by the kidney vascular lesions.

Hepatitis E virus and the kidney in solid-organ transplant patients

BACKGROUND

Hepatitis E virus (HEV) infection is an emerging disease in industrialized countries. Few data regarding genotype 3 HEV extrahepatic manifestations exist.

METHODS

We assessed kidney function and histology in solid-organ transplant patients during HEV infection. In all, 51 cases of genotype 3 HEV infections were diagnosed (34 kidney, 14 liver, and 3 kidney-pancreas transplant patients). Of these, 43.2% were cleared of the virus spontaneously within 6 months of infection, whereas 56.8% evolved to chronic hepatitis. Twelve of these patients completed a 3-month antiviral therapy and were followed up for 6 months posttreatment. Kidney function (estimated glomerular filtration rate [eGFR] obtained by the Modification of Diet in Renal Disease equation) and proteinuria were assessed before infection, during HEV infection and during follow-up. Kidney biopsies were obtained from patients with high proteinuria and decreased eGFR levels.

RESULTS

During HEV infection, there was a significant decrease in eGFR in both kidney- and liver-transplant patients. Glomerular diseases were observed in kidney biopsies obtained during the acute and chronic phases. This included membranoproliferative glomerulonephritis and relapses in IgA nephropathy. The majority of patients had cryoglobulinemia that became negative after HEV clearance. Kidney function improved and proteinuria decreased after HEV clearance.

CONCLUSION

HEV-associated glomerulonephritis seems to be an HEV-related extrahepatic manifestation. Further studies are required to confirm these observations.