Liver Transplant Recipients With End-Stage Renal Disease Largely Benefit From Kidney Transplantation

Optimization and Protection of Kidney Health in Liver Transplant Recipients: Intra- and Postoperative Approaches

Postoperative acute kidney injury after liver transplant (LT) has long-term implications for kidney health. LT recipients are at risk of acute kidney injury due to a number of factors related to the donor liver, intraoperative factors including surgical technique, as well as recipient factors, such as pre-LT kidney function and postoperative complications. This review discusses these factors in detail and their impact on posttransplant kidney function. Long-term risk factors such as calcineurin inhibitors have also been discussed. Additionally, the impact of liver allocation policies on pre- and post-LT kidney health is discussed.

Chronic Kidney Disease After Liver Transplantation

Chronic kidney disease among liver transplant recipients is common and associated with an increased mortality risk. Several risk factors and causes for the development of chronic kidney disease have been identified. They can be divided into perioperative factors, such as unresolved acute kidney injury; donor-related factors, such as the use of extended criteria liver allografts; and recipient-related factors, such as the use of calcineurin inhibitors and the presence of metabolic syndrome, diabetes, and obesity. There is a bimodal progression, more prominent during the initial post-transplant months, followed by a gradual but progressive decline over the subsequent years. Management strategies to prevent and treat chronic kidney disease in the general population can be reasonably applied to the liver transplant population and include addressing comorbidities such as hypertension and diabetes. Strategies to minimize or withdraw calcineurin inhibitors from the immunosuppressive regimen can slow progression of kidney dysfunction. Patients with advanced chronic kidney disease should be considered for kidney transplantation due to its survival advantage. Allocation policy in the United States confers safety-net allocation priority for liver transplant recipients who develop advanced chronic kidney disease within the first year of liver transplantation.

Identification of Multiple Hub Genes in Acute Kidney Injury after Kidney Transplantation by Bioinformatics Analysis

Background and Objectives: The molecular mechanisms of the development of acute kidney injury (AKI) after kidney transplantation are not yet clear. The aim of this study was to confirm the genes and mechanisms related to AKI after transplantation. Materials and Methods: To investigate potential genetic targets for AKI, an analysis of the gene expression omnibus database was used to identify key genes and pathways. After identification of differentially expressed genes, Kyoto Encyclopedia of Genes and Genome pathway enrichment analyses were performed. We identified the hub genes and established the protein-protein interaction network. Results: Finally, we identified 137 differentially expressed genes (59 upregulated genes and 16 downregulated genes). AKAP12, AMOT, C3AR1, LY96, PIK3AP1, PLCD4, PLCG2, TENM2, TLR2, and TSPAN5 were filtrated by the hub genes related to the development of post-transplant AKI from the Protein-Protein Interaction (PPI) network. Conclusions: This may provide important evidence of the diagnostic and therapeutic biomarker of AKI.

[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.

Utilization and effectiveness of the organ procurement and transplantation network "safety-net" policy

BACKGROUND

Liver transplant recipients with persistent renal dysfunction may be prioritized on the kidney transplant waitlist based on the Organ Procurement and Transplantation Network "safety-net" policy implemented in 2017. The aim of this study was to evaluate the utilization of kidney transplant and posttransplant outcomes, of liver transplant recipients with persistent renal dysfunction before and after implementation of the Organ Procurement and Transplantation Network kidney safety-net policy and standardization of simultaneous liver-kidney requirements.

METHODS

Using the United Network for Organ Sharing database from January 2015 to March 2019, outcomes of liver transplant recipients listed for kidney transplant and the subset who received kidney after liver transplants were compared before and after policy implementation.

RESULTS

Liver transplant recipients listed for kidney transplant increased from 58 to 200, and kidney after liver transplants increased from 29.3% to 42.5% after safety-net policy implementation. Post-policy kidney after liver transplants received more local organs (91.8% vs 70.6%, P = .03) and trended toward shorter waitlist time (47 [17-123] vs 84 [37-226] days, P = .051). The pre- and post-policy cohorts had similar (P > .05) kidney donor profile index (0.43 [0.27-0.69] vs 0.42 [0.28-0.58]) and delayed graft function (11.8% vs 14.1%). Patient, kidney graft, and liver graft survival were similar (P > .05) between pre and post-policy cohorts. Patient and kidney graft survival were similar between kidney after liver transplants and propensity score-matched kidney transplant alone recipients. Patient, kidney, and liver graft survival were similar between kidney after liver transplants and propensity score-matched simultaneous liver-kidney transplant recipients.

CONCLUSION

This study demonstrates that after Organ Procurement and Transplantation Network "safety-net" policy implementation, there has been an increase in liver transplant recipients with renal dysfunction who are listed for and undergo kidney transplant with excellent short-term results.

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.

Peritoneal Dialysis After Liver Transplantation: A Systematic Review

Background:

Chronic kidney disease following liver transplantation is a major long-term complication. Most liver transplant recipients with kidney failure will be treated with dialysis instead of kidney transplantation due to noneligibility and shortage in organ availability. In this population, the role of peritoneal dialysis (PD) as a modality of kidney replacement therapy (KRT) remains unclear.

Objective:

To determine the feasibility regarding safety, technique survival, and dialysis efficiency of PD in liver transplant recipients requiring KRT for maintenance dialysis.

Design:

Systematic review.

Setting:

Interventional and observational studies reporting the use of PD after liver transplantation.

Patients:

Adult liver transplant recipients with kidney failure treated with maintenance KRT.

Measurements:

Extracted data included eligibility criteria, study design, demographics, and PD modality. The following outcomes of interest were extracted: rate of peritonitis and microorganisms involved, noninfectious peritoneal complications, technique survival, and kidney transplantation-censored technique survival. Non-PD complications included overall survival, liver graft dysfunction, and hospitalization rate.

Methods:

The following databases were searched until July 2020: MedLine/PubMed, EMBASE, CINAHL, and Cochrane Library. Two reviewers independently screening all titles and abstracts of all identified articles. Due to the limited sample size, observational designs and study heterogeneity expected, no meta-analysis was pre-planned. Descriptive statistics were used to report all results.

Results:

From the 5263 identified studies, 4 were included in the analysis as they reported at least 1 outcome of interest on a total of 21 liver transplant recipients, with an overall follow-up duration on PD of 19.0 (Interquartile range [IQR]: 9.5-29.5) months. Fifteen episodes of peritonitis occurred in a total cumulative PD follow-up of 514 patient-months, representing an incidence rate of 0.35 per year. These episodes did not result in PD technique failure, mortality, or impairment of liver graft function.

Limitations:

Limitations include the paucity of studies in the field and the small number of patients included in each report, a risk of publication bias and the impossibility to directly compare hemodialysis to PD in this population. These results, therefore, must be interpreted with caution.

Conclusions:

Based on limited data reporting the feasibility of PD in liver transplant recipients with kidney failure, no signal was associated with an increased risk of infectious complications. Long-term studies evaluating this modality need to be performed.

Registration (PROSPERO):

CRD42020218374.

The mRNA landscape profiling reveals potential biomarkers associated with acute kidney injury AKI after kidney transplantation

Background

This study aims to identify potential biomarkers associated with acute kidney injury (AKI) post kidney transplantation.

Material and Methods

Two mRNA expression profiles from Gene Expression Omnibus repertory were downloaded, including 20 delayed graft function (DGF) and 68 immediate graft function (IGF) samples. Differentially expressed genes (DEGs) were identified between DGF and IGF group. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis of DEGs were performed. Then, a protein-protein interaction analysis was performed to extract hub genes. The key genes were searched by literature retrieval and cross-validated based on the training dataset. An external dataset was used to validate the expression levels of key genes. Receiver operating characteristic curve analyses were performed to evaluate diagnostic performance of key genes for AKI.

Results

A total of 330 DEGs were identified between DGF and IGF samples, including 179 up-regulated and 151 down-regulated genes. Of these, OLIG3, EBF3 and ETV1 were transcription factor genes. Moreover, LEP, EIF4A3, WDR3, MC4R, PPP2CB, DDX21 and GPT served as hub genes in PPI network. EBF3 was significantly up-regulated in validation GSE139061 dataset, which was consistently with our initial gene differential expression analysis. Finally, we found that LEP had a great diagnostic value for AKI (AUC = 0.740).

Conclusion

EBF3 may be associated with the development of AKI following kidney transplantation. Furthermore, LEP had a good diagnostic value for AKI. These findings provide deeper insights into the diagnosis and management of AKI post renal transplantation.

Kidney After Liver Transplantation Matched-pair Analysis: Are Kidneys Allocated to Appropriate Patients to Maximize Their Survival?

BACKGROUND

Kidney after liver transplantation (KALT) is the best therapeutic option for patients with end-stage renal disease after orthotopic liver transplantation (OLT). New allocation policies prioritize kidneys to patients in renal failure within the first year following OLT. There is little data on how kidney quality, measured by kidney donor profile index (KDPI), impacts KALT survival outcomes.

METHODS

The United Network for Organ Sharing database was queried for adult KALT recipients from 1988 to 2015 and compared to their paired kidney transplant alone (KTA) recipients. Seven hundred forty-five pairs were stratified into 3 KDPI subgroups and compared patient survival, graft survival, and death-censored graft survival among matched-paired recipients.

RESULTS

Overall, KTA recipients had superior patient and graft survival compared with the KALT group. KTA patient survival was superior for all 3 KDPI subgroups analysis. KTA graft survival was superior compared with KALT recipients of KDPI 21%-85% kidneys. Inferior graft half-life was observed in KALT versus KTA recipients with KDPI 21%-85% and >85%.

CONCLUSIONS

From a utilitarian perspective, it is important that kidneys are allocated to recipients that are able to maximize their benefit from the full life of the organ. In KTA recipients, graft quality correlates directly to graft survival. However, in KALT patients receiving the matched-pair kidneys of the KTA recipients, patient mortality, rather than kidney quality, dictates graft survival significantly. As allocation practices continue developing, utilization of expanded criteria kidneys that better match anticipated patient and graft survival should be strongly considered to maximize the benefits of limited resources for the greatest number of patients.

Deceased Donor Predictors for Pediatric Liver Allograft Utilization

BACKGROUND

The number of pediatric deceased organ donors has recently declined, and the nonutilization of pediatric liver allografts has limited the development of liver transplantation. We determined the utilization rate of pediatric livers and identified risk factors for graft discard.

METHODS

We used data from the Scientific Registry of Transplant Recipients database from January 1, 2000, to December 31, 2012. The trends of pediatric liver donors and utilization rates were analyzed. Donor risk factors that impacted the graft use of pediatric livers were measured. Logistic regression modelling was performed to evaluate graft utilization and risk factors.

RESULTS

A total of 11,934 eligible pediatric liver donors were identified during this period. A total of 1191 authorized liver grafts did not recover or recovered without transplantation. Factors including pediatric donors >1 year of age (odds ratio [OR] = 2.956, 95% confidence interval [CI] 2.494-3.503, P < .001), nonhead trauma (OR = 2.243, 95% CI 1.903-2.642, P < .001), lack of heartbeat (OR = 7.534, 95% CI 5.899-9.623, P < .001), hepatitis B surface antigen positivity (OR = 4.588, 95% CI 1.021-20.625, P = .047), anti-hepatitis C virus positivity (OR = 4.691, 95% CI 1.352-16.280, P = .015), total bilirubin >1 mg/dL (OR = 1.743, 95% CI 1.469-2.068, P < .001), and blood urea nitrogen >21 mg/dL (OR = 1.941, 95% CI 1.546-2.436, P < .001) were significantly related to graft nonutilization. Steroids or diuretics administered prerecovery were significantly related to graft utilization (OR = 0.684, 95% CI 0.581-0.806, P < .001; OR = 0.744, 95% CI 0.634-0.874, P < .001; respectively).

CONCLUSIONS

The pediatric liver allograft utilization rate and risk factors for nonutilization of grafts were determined.

Liver Retransplantation Associated With Kidney Transplantation for End-stage Liver Graft Disease and Renal Insufficiency: A Morbid Procedure on a Unique Subgroup of Patients

BACKGROUND

Chronic renal disease (CKD) jeopardizes the long-term outcomes of liver transplant recipients. In patients with end-stage liver graft disease and CKD, liver retransplantation associated with kidney transplantation (ReLT-KT) might be necessary. Yet, this specific subset of patients remains poorly described.

METHODS

Indications, perioperative characteristics, and short- and long-term outcomes of patients undergoing ReLT-KT at 2 transplantation units from 1994 to 2012 were analyzed. Risk factors for postoperative mortality and long-term survivals were evaluated.

RESULTS

Among 3060 patients undergoing liver transplantation (LT), 45 (1.5%) underwent ReLT-KT. The proportion of ReLT-KT among LT recipients continuously grew throughout the study period from 0.3% to 2.4% (P < 0.001). Median time from primary LT to ReLT-KT was 151.3 (7.5-282.9) months. The most frequent indications for liver retransplantation were recurrence of the primary liver disease and cholangitis in 15 (33.3%) cases each. CKD was related to calcineurin inhibitors toxicity in 38 (84.4%) cases. Twelve (26.7%) patients died postoperatively. D-MELD (donor age × recipients' MELD) was associated with postoperative mortality (HR: 8.027; 95% CI: 2.387-18.223; P = 0.026) and optimal cut-off value was 1039 (AUC: 0.801; P = 0.002). Overall 1, 3, and 5 years survivals were 68.8%, 65.9%, and 59.5%, respectively. D-MELD > 1039 was the only factor associated with poor survival (P = 0.021).

CONCLUSIONS

ReLT-KT is a highly morbid increasingly performed procedure. Refinements in the selection of grafts and transplant candidates are required to limit the postoperative mortality of these patients.

Decreased Expression of MicroRNA-107 in B Lymphocytes of Patients with Antibody-Mediated Renal Allograft Rejection

MicroRNAs (miRNAs) are small noncoding RNA molecules that participate in normal B cell lineage development through posttranscriptional gene regulation. Antibody-mediated renal allograft rejection (ABMR) is emerging as one of the most common serious threats to renal transplant patients. In this study, we explored the role of miRNAs in the pathogenesis of ABMR. The differentially expressed miRNAs were identified by Affymetrix miRNA microarray analysis using B lymphocytes from 5 recipients and 5 volunteers. Based on quantitative RT-PCR, the expression levels of miR-107 were lower in the B lymphocytes from recipients than in those from volunteers. Computational analysis predicted that 3'-untranslated region of the autophagy-related protein 12 (ATG12) mRNA was targeted by miR-107, and we identified ATG12 as a target of miR-107 by Luciferase assay. Importantly, the expression levels of ATG12 in B lymphocytes of recipients were higher than those in the volunteer group, and miR-107 mimic significantly decreased ATG12 expression and formation of autolysosomes in B lymphocytes of recipients. Furthermore, we observed that levels of autophagy in B lymphocytes of transplant recipients were higher than those in B cells from volunteers. These findings suggest that miR-107 may contribute to the regulation of autophagy via targeting ATG12. Lastly, treatment with an miR-107 mimic caused the decrease in the secretion of IgG and IgM antibodies from B lymphocytes of transplant recipients, indicating that deregulated miR-107 could be involved in the pathogenesis of ABMR. Taken together, we propose that decreased miR-107 expression is associated with autophagy activation in B lymphocytes from patients with ABMR.