Outcome of kidney transplant in primary, repeat, and kidney-after-nonrenal solid-organ transplantation: 15-year analysis of recent UNOS database

NSD2 modulates Drp1-mediated mitochondrial fission in chronic renal allograft interstitial fibrosis by methylating STAT1

Renal interstitial fibrosis/tubular atrophy (IF/TA) is a prominent pathological feature of chronic allograft dysfunction (CAD). Our previous study has demonstrated that epithelial-mesenchymal transition (EMT) plays a significant role in shaping the development of IF/TA. Nuclear SET domain (NSD2), a histone methyltransferase catalyzing methylation at lysine 36 of histone 3, is crucially involved in the development and progression of solid tumors. But its role in the development of renal allograft interstitial fibrosis has yet to be elucidated. Here, we characterize NSD2 as a crucial mediator in the mouse renal transplantation model in vivo and a model of tumor necrosis factor-α (TNF-α) stimulated-human renal tubular epithelial cells (HK-2) in vitro. Functionally, NSD2 knockdown inhibits EMT, dynamin-related protein 1 (Drp1)-mediated mitochondrial fission in mice. Conversely, NSD2 overexpression exacerbates fibrosis-associated phenotypes and mitochondrial fission in tubular cells. Mechanistically, tubular NSD2 aggravated the Drp-1 mediated mitochondrial fission via STAT1/ERK/PI3K/Akt signaling pathway in TNF-α-induced epithelial cell models. Momentously, mass spectrometry (MS) Analysis and site-directed mutagenesis assays revealed that NSD2 interacted with and induced Mono-methylation of STAT1 on K173, leading to its phosphorylation, IMB1-dependent nuclear translocation and subsequent influence on TNF-α-induced EMT and mitochondrial fission in NSD2-dependent manner. Collectively, these findings shed light on the mechanisms and suggest that targeting NSD2 could be a promising therapeutic approach to enhance tubular cell survival and alleviate interstitial fibrosis in renal allografts during CAD.

[Surgical outcomes and complications following third kidney transplantation]

BACKGROUND

After two consecutive kidney transplant failures, a third kidney transplantation improves survival for patients on the waiting list. The surgical outcomes and complications of third kidney transplantations remain poorly known.

METHODS

We analyzed the last 100 third kidney transplantations performed in our center between January 2000 and August 2018. The data, relating to donors and recipients, were extracted retrospectively from medical records and from the prospective DIVAT database (computerized and validated data in transplantation). Continuous variables are expressed as means, medians, first and third quartiles (median, [Q1;Q3]). Categorical variables are expressed as percentages. Patient and transplant survivals were calculated using the Kaplan-Meier method.

RESULTS

Mean age of recipients was 46.4 years (47, [36;53]). Thirty-five percent had kidney failure due to urinary tract malformations. Mean age of donors was 48.2 years (52, [39.75; 58]) with 63% of donors with standard criteria. Mean cold ischemia time was 22.4hours (21, [16.5; 29.2]). Surgical mortality rate was 2% and surgical complication rate was 45%. Third kidney transplants survival was 73.1% and 58.8% at 5 years and 10 years. Mortality rate with a functioning transplant was 18%.

CONCLUSION

A third kidney transplant offers satisfactory functional outcomes but remains associated with high morbi-mortality and a significant death rate with a functioning transplant.

LEVEL OF EVIDENCE: 4

Disruption of RCAN1.4 expression mediated by YY1/HDAC2 modulates chronic renal allograft interstitial fibrosis

Chronic allograft dysfunction (CAD) is a major factor that hinders kidney transplant survival in the long run. Epithelial-mesenchymal transition (EMT) has been confirmed to significantly contribute to interstitial fibrosis/tubular atrophy (IF/TA), which is the main histopathological feature of CAD. Aberrant expression of the regulator of calcineurin 1 (RCAN1), recognized as an endogenous inhibitor of the calcineurin phosphatase, has been shown to be extensively involved in various kidney diseases. However, it remains unclear how RCAN1.4 regulates IF/TA formation in CAD patients. Herein, an in vivo mouse renal transplantation model and an in vitro model of human renal tubular epithelial cells (HK-2) treated with tumor necrosis factor-α (TNF-α) were employed. Our results proved that RCAN1.4 expression was decreased in vivo and in vitro, in addition to the up-regulation of Yin Yang 1 (YY1), a transcription factor that has been reported to convey multiple functions in chronic kidney disease (CKD). Knocking in of RCAN1.4 efficiently attenuated chronic renal allograft interstitial fibrosis in vivo and inhibited TNF-α-induced EMT in vitro through regulating anti-oxidative stress and the calcineurin/nuclear factor of activated T cells cytoplasmic 1 (NFATc1) signaling pathway. In addition, suppression of YY1 mediated by shRNA or siRNA alleviated TNF-α-induced EMT through abolishing reactive species partly in an RCAN1.4-dependent manner. Notably, we confirmed that YY1 negatively regulated RCAN1.4 transcription by directly interacting with the RCAN1.4 promoter. In addition, histone deacetylase 2 (HDAC2) interacted with YY1 to form a multi-molecular complex, which was involved in TNF-α-induced RCAN1.4 transcriptional repression. Therefore, RCAN1.4 is suggested to be modulated by the YY1/HDAC2 transcription repressor complex in an epigenetic manner, which is a mediated nephroprotective effect partly through modulating O2⋅- generation and the calcineurin/NFATc1 signaling pathway. Thus, the YY1-RCAN1.4 axis constitutes an innovative target for IF/TA treatment in CAD patients.

Benefit of Kidney Transplantation for Post Lung Transplantation Renal Failure

INTRODUCTION

Nephrotoxicity is a significant side effect of thoracic transplantation. Many lung transplant patients will require subsequent renal transplantation (KAL). Recently, simultaneous lung/kidney transplants (SLuK) have become an attractive option for patients with end-stage renal disease at the time of lung transplantation. This article explores SLuK outcomes compared to conventional KAL, as well as outcomes among KAL patients against those were KAL listed but never transplanted.

MATERIALS AND METHODS

The United Network for Organ Sharing/the Organ Procurement and Transportation Network database was used to identify SLuK patients (n = 74), KAL transplants (n = 456), and patients who were listed for KAL but were never transplanted (n = 626). Significance was determined by chi², Wilcoxon rank sum test, or independent t-tests. Death-censored graft survival for subgroups was estimated using Kaplan-Meier with log-rank for significance. Analyses were completed using SPSS Statistics 28.

RESULTS

The SLuK cohort was older (P = 0.04), more likely diabetic (P < 0.001), and had shorter life expectancies (P < 0.001) than KAL patients. Of those SLuK transplants within 5 y, 84% of patients were alive 1 y post transplant and 82% were alive 3 y post-transplant (compared to 74.6% and 60.3% of overall SLuK). Patients who did undergo KAL were younger and had a lower body mass index (both P < 0.001) compared to those who did not. Those who received a kidney had increased survival times compared to WL patients (P < 0.001).

CONCLUSIONS

Conventional KAL transplants are still favorable for average lung recipients. However, recent improvements have made SLuK an option for patients with renal dysfunction. Those patients who were able to receive KAL transplants were better surgical candidates than those who remained on the waitlist.

National Trends in Transplantation-Associated Intensive Care Unit Admission in South Korea From 2010 to 2019

BACKGROUND

We aimed to investigate the mortality and associated factors among patients admitted to the intensive care unit (ICU) after transplantation in South Korea.

MATERIALS AND METHODS

The South Korean National Health Insurance Service database was used as the data source. All adult patients (age ≥18 years) who were admitted to the ICU for organ transplantation-related causes from January 1, 2010 to December 31, 2019 (10 years) were included. Transplantation-associated ICU admissions were defined as admissions to the ward and ICU after transplantation or to the ICU before transplantation.

RESULTS

A total of 23,994 ICU admissions after transplantation were included in the analysis (mean [SD] age: 52.7 [10.7] years; men: 67.0%; kidney transplantation: n = 9638; liver transplantation: n = 12,196; heart and/or lung transplantation: n = 1829; pancreas or small bowel transplantation: n = 331). Transplantation-associated ICU admissions gradually increased from 1666 in 2010 to 3014 in 2019. The 1-year mortality rates were 21.2%, 12.3%, 4.2%, and 3.0% after heart and/or lung, liver, pancreas or small bowel, and kidney transplantation, respectively. Invasive life support procedures during ICU stay, comorbidities, and older age were potential risk factors for 1-year mortality after transplantation.

CONCLUSION

Transplantation-associated ICU admissions gradually increased from 2010 to 2019 in South Korea. The 1-year mortality rate after transplantation was the highest in the heart and/or lung transplantation group, followed by those of the liver, pancreas or small bowel, and kidney transplantation groups.

The strategy of diminishing age gap effect on different donor-recipient combinations in living donor kidney transplantation

BACKGROUND

The disparity between kidney donation and the number of uremic patients on the waiting list has increased the demand for older live-donor kidneys (OLK). However, the donor-recipient age gap may have an impact on the recipient's outcome.

METHODS

Patients who underwent living donor kidney transplantation at our institute between 2005 and 2019 were enrolled and categorized into four donor-recipient groups according to age (≥50 years and <50 years). The Estimated Post-Transplant Survival (EPTS) score was used to quantify the recipient's condition. Adjusted models analyzed recipient outcomes and related risks among the four groups.

RESULTS

Of the 154 pairs of live donors and recipients, OLK did not influence overall or death-censored graft survival. The four donor-recipient combinations had similar recipient outcomes, except it slightly worsened in the "old donor to young recipient" group. The EPTS score (adjusted HR, 1.02; 95% CI, 1.01-1.04; p = 0.014) and rejection (adjusted HR, 4.26; 95% CI, 1.36-13.37; p = 0.013) were significant risk factors for overall and death-censored graft survival, respectively. Recipients with pretransplant diabetes or prior solid organ transplantation could have amplified risk effects. The main causes of graft loss were death in older recipients and chronic rejection in younger recipients.

CONCLUSION

OLK is safe for young recipients. Nevertheless, adequate immunosuppression should be maintained to prevent rejection and subsequent graft loss, especially for those receiving second kidney transplantation. In contrast, older recipients should avoid overt immunosuppression and control their comorbidities, such as diabetes-related complications to improve their long-term outcomes.

Kidney disease in non-kidney solid organ transplantation

Kidney disease after non-kidney solid organ transplantation (NKSOT) is a common post-transplant complication associated with deleterious outcomes. Kidney disease, both acute kidney injury and chronic kidney disease (CKD) alike, emanates from multifactorial, summative pre-, peri- and post-transplant events. Several factors leading to kidney disease are shared amongst solid organ transplantation in addition to distinct mechanisms unique to individual transplant types. The aim of this review is to summarize the current literature describing kidney disease in NKSOT. We conducted a narrative review of pertinent studies on the subject, limiting our search to full text studies in the English language. Kidney disease after NKSOT is prevalent, particularly in intestinal and lung transplantation. Management strategies in the peri-operative and post-transplant periods including proteinuria management, calcineurin-inhibitor minimization/ sparing approaches, and nephrology referral can counteract CKD progression and/or aid in subsequent kidney after solid organ transplantation. Kidney disease after NKSOT is an important consideration in organ allocation practices, ethics of transplantation. Kidney disease after SOT is an incipient condition demanding further inquiry. While some truths have been revealed about this chronic disease, as we have aimed to describe in this review, continued multidisciplinary efforts are needed more than ever to combat this threat to patient and allograft survival.

Trends in underlying causes of death in solid organ transplant recipients between 2010 and 2020: Using the CLASS method for determining specific causes of death

Monitoring specific underlying causes of death in solid organ transplant (SOT) recipients is important in order to identify emerging trends and health challenges. This retrospective cohort study includes all SOT recipients transplanted at Rigshospitalet between January 1st, 2010 and December 31st, 2019. The underlying cause of death was determined using the newly developed Classification of Death Causes after Transplantation (CLASS) method. Cox regression analyses assessed risk factors for all-cause and cause-specific mortality. Of the 1774 SOT recipients included, 299 patients died during a total of 7511 person-years of follow-up (PYFU) with cancer (N = 57, 19%), graft rejection (N = 55, 18%) and infections (N = 52, 17%) being the most frequent causes of death. We observed a lower risk of all-cause death with increasing transplant calendar year (HR 0.91, 95% CI 0.86–0.96 per 1-year increase), alongside death from graft rejection (HR 0.84 per year, 95% CI 0.74–0.95) and death from infections (HR 0.86 per year, 95% CI 0.77–0.97). Further, there was a trend towards lower cumulative incidence of death from cardiovascular disease, graft failure and cancer in more recent years, while death from other organ specific and non-organ specific causes did not decrease. All-cause mortality among SOT recipients has decreased over the past decade, mainly due to a decrease in graft rejection- and infection-related deaths. Conversely, deaths from a broad range of other causes have remained unchanged, suggesting that cause of death among SOT recipients is increasingly diverse and warrants a multidisciplinary effort and attention in the future.

Pretransplant characteristics of kidney transplant recipients that predict posttransplant outcome

Better characterization of the potential kidney transplant recipient using novel biomarkers, for example, pretransplant plasma endotrophin, will lead to improved outcome after transplantation. This mini-review will focus on current knowledge about pretransplant recipients’ characteristics, biomarkers, and immunology. Clinical characteristics of recipients including age, obesity, blood pressure, comorbidities, and estimated survival scores have been introduced for prediction of recipient and allograft survival. The pretransplant immunologic risk assessment include histocompatibility leukocyte antigens (HLAs), anti-HLA donor-specific antibodies, HLA-DQ mismatch, and non-HLA antibodies. Recently, there has been the hope that pretransplant determination of markers can further improve the prediction of posttransplant complications, both short-term and long-term outcomes including rejections, allograft loss, and mortality. Higher pretransplant plasma endotrophin levels were independently associated with posttransplant acute allograft injury in three prospective European cohorts. Elevated numbers of non-synonymous single-nucleotide polymorphism mismatch have been associated with increased allograft loss in a multivariable analysis. It is concluded that there is a need for integration of clinical characteristics and novel molecular and immunological markers to improve future transplant medicine to reach better diagnostic decisions tailored to the individual patient.

Understanding disparities and barriers associated with pediatric transplant evaluation and time to listing: Moving toward a more comprehensive picture

BACKGROUND

Delayed time to listing (TTL) for pediatric transplant patients is associated with increased risks of mortality and morbidity. The full range of health disparities, sociodemographic factors, and other barriers associated with delays in listing in the pediatric transplant candidate evaluation process has not been fully examined.

METHODS

Retrospective chart reviews were conducted for 183 kidney, liver, and heart transplant candidates ages 0-18 who were referred for evaluation during 2012-2015. Demographic information and potential barriers (e g., social/medical factors, financial concerns) were gathered from pre-transplant evaluations and included in a comprehensive model to evaluate mechanisms that explain differences in TTL. Descriptive statistics, logistic regression models, Cox proportional hazards models, and path analysis were used for analyses.

RESULTS

Candidates included 26.8% heart, 33.3% liver, and 39.9% kidney patients. The most common barrier to listing was financial (71.6%), followed by caregiver psychological or substance use (57.9%), and medical problems (49.7%). Higher age, kidney, and liver organ type (relative to the heart), and presence of social, medical, administrative/motivation, and financial barriers were all directly associated with longer TTL. Public insurance was indirectly associated with TTL through social, administrative/motivation, and financial barriers. Organ type was indirectly associated with TTL through financial barriers.

CONCLUSIONS

Results suggest social problems, administrative issues, and financial issues act as mechanisms through which insurance type and liver transplant candidates face increased risk of delays in transplant listing time. There are numerous clinical implications and interventions that are warranted to reduce TTL among pediatric transplant candidates with co-occurring barriers.

Everolimus Alleviates Renal Allograft Interstitial Fibrosis by Inhibiting Epithelial-to-Mesenchymal Transition Not Only via Inducing Autophagy but Also via Stabilizing IκB-α

Chronic allograft dysfunction (CAD) is the major cause of late graft loss in long-term renal transplantation. In our previous study, we found that epithelial–mesenchymal transition (EMT) is a significant event in the progression of renal allograft tubulointerstitial fibrosis, and impaired autophagic flux plays a critical role in renal allograft fibrosis. Everolimus (EVR) has been reported to be widely used to prevent the progression of organ fibrosis and graft rejection. However, the pharmacological mechanism of EVR in kidney transplantation remains to be determined. We used CAD rat model and the human kidney 2 (HK2) cell line treated with tumor necrosis factor-α (TNF-α) and EVR to examine the role of EVR on TNF-α-induced EMT and transplanted renal interstitial fibrosis. Here, we found that EVR could attenuate the progression of EMT and renal allograft interstitial fibrosis, and also activate autophagy in vivo. To explore the mechanism behind it, we detected the relationship among EVR, autophagy level, and TNF-α-induced EMT in HK2 cells. Our results showed that autophagy was upregulated upon mTOR pathway inhibition by EVR, which could significantly reduce expression of TNF-α-induced EMT. However, the inhibition of EVR on TNF-α-induced EMT was partly reversed following the addition of autophagy inhibitor chloroquine. In addition, we found that TNF-α activated EMT through protein kinase B (Akt) as well as nuclear factor kappa B (NF-κB) pathway according to the RNA sequencing, and EVR’s effect on the EMT was only associated with IκB-α stabilization instead of the Akt pathway. Together, our findings suggest that EVR may retard impaired autophagic flux and block NF-κB pathway activation, and thereby prevent progression of TNF-α-induced EMT and renal allograft interstitial fibrosis.

CKD in Recipients of Nonkidney Solid Organ Transplants: A Review

Chronic kidney disease (CKD) after solid organ transplant is a common clinical presentation, affecting 10% to 20% of liver, heart and lung transplant recipients and accounting for approximately 5% of the kidney transplant waiting list. The causes of CKD are different for different types of transplants and are not all, or even predominantly, due to calcineurin inhibitor toxicity, with significant heterogeneity particularly in liver transplant recipients. Many solid organ transplant recipients with advanced CKD benefit from kidney transplantation, but have a higher rate of death while waitlisted and higher mortality following transplant than the general kidney failure population. Recent organ allocation policies and proposals have attempted to address the appropriate identification and prioritization of candidates in need of a kidney transplant, either simultaneous with or following non-kidney transplant. Future research should focus on predictive factors for individuals identified at high risk for progression to kidney failure and death, and strategies to preserve kidney function and minimize the CKD burden in this unique patient population.

Efficacy and safety of Sodium-Glucose-Transporter-2 inhibitors in kidney transplant patients

PURPOSE OF REVIEW

This review discusses current evidence and future perspectives for use of SLT2 inhibitors in kidney transplant recipients (KTRs).

RECENT FINDINGS

Sodium-Glucose-Transporter-2 inhibitors (SGLT2is) lower plasma glucose in patients with type 2 diabetes, and protect against heart failure and progression of chronic kidney disease by a glucose-independent mechanism. Most of the current studies with SGLT2is in kidney transplant patients are however short-term retrospective case studies. These, together with one small randomized clinical trial, show that SGLT2is lower glucose also in KTRs with type 2 diabetes or posttransplant diabetes mellitus. Larger reductions in HbA1c (-0.5 to 1.5% points) are seen only in patients with estimated GFR > 60 ml/min/1.73m2 and HbA1c > 8%. With lower gomerular filtration rate (GFR) or glycated hemoglobin (HbA1c) the glucose-lowering effect is trivial. However, a reduction in body weight, blood pressure and uric acid is also seen, whereas the frequency of side effects (mycotic or urinary tract infections) does not seem to exceed what is seen in nontransplanted patients. Long-term effects on GFR have not been studied in kidney transplanted patients, but SGLT2is induce an early dip in GFR also in these patients. This could signal a beneficial long-term effect on renal hemodynamics.

SUMMARY

SGLT2is lower glucose safely also in patients with single kidney grafts, but long-term kidney function and patient survival are yet to be explored.

Kidney Disease After Nonkidney Solid Organ Transplant

Nonkidney solid organ transplants (NKSOTs) are increasing in the United States with improving long-term allograft and patient survival. CKD is prevalent in patients with NKSOT and is associated with increased morbidity and mortality especially in those who progress to end-stage kidney disease. Calcineurin inhibitor nephrotoxicity is a main contributor to CKD after NKSOT, but other factors in the pretransplant, peritransplant, and post-transplant period can predispose to progressive kidney dysfunction. The management of CKD after NKSOT generally follows society guidelines for native kidney disease. Kidney-protective and calcineurin inhibitor-sparing immunosuppression has been explored in this population and warrants a discussion with transplant teams. Kidney transplantation in NKSOT recipients remains the kidney replacement therapy of choice for suitable candidates, as it provides a survival benefit over remaining on dialysis.

The Relationship between Timing of Pretransplant Kidney Biopsy, Graft Loss, and Survival in Kidney Transplantation: An Italian Cohort Study

INTRODUCTION

Kidney biopsy is performed to assess if an extended criteria graft can be used for transplantation. It may be performed before or after cross-clamping during organ procurement. This study aims to evaluate whether the timing of biopsy may modify cold ischemia times (CIT) and/or graft outcomes.

METHODS

Kidney transplants performed in our center from January 2007 to December 2017 were analyzed. Grafts with preimplantation kidney biopsy were included. Biopsies were performed during surgical back table (ex situ kidney biopsy [ESKB]) until 2012 and since then before the aortic cross-clamping (in situ kidney biopsy [ISKB]). To overcome biases owing to different distributions, a propensity score model was developed. The study population consists in 322 patients, 115 ESKB, and 207 ISKB.

RESULTS

CIT was significantly lower for ISKB (730 min ISKB vs. 840 min ESKB, p value = 0.001). In both crude (OR 0.27; 95% confidence interval, 95% CI 0.12-0.60; p value = 0.002) and adjusted analyses (OR 0.37; 95% CI 0.14-0.94; p value = 0.039), ISKB was associated with a reduced odd of graft loss when compared to ESKB.

DISCUSSION/CONCLUSION

Performing preimplantation kidney biopsy during the recovery, prior to the aortic cross-clamping, may be a strategy to reduce CIT and improve transplant outcomes.

Simultaneous heart-kidney transplantation results in respectable long-term outcome but a high rate of early kidney graft loss in high-risk recipients - a European single center analysis

BACKGROUND

In spite of renal graft shortage and increasing waiting times for transplant candidates, simultaneous heart and kidney transplantation (HKTx) is an increasingly performed procedure established for patients with combined end-stage cardiac and renal failure. Although data on renal graft outcome in this setting is limited, reports on reduced graft survival in comparison to solitary kidney transplantation (KTx) have led to an ongoing discussion of adequate organ utilization.

METHODS

This retrospective study was conducted to evaluate prognostic factors and outcomes of 27 patients undergoing HKTx in comparison to a matched cohort of 27 patients undergoing solitary KTx between September 1987 and October 2019 in one of Europe's largest transplant centers.

RESULTS

Median follow-up was 100.33 (0.46-362.09) months. Despite lower five-year kidney graft survival (62.6% versus 92.1%; 111.73 versus 183.08 months; p = 0.189), graft function and patient survival (138.90 versus 192.71 months; p = 0.128) were not significantly inferior after HKTx in general. However, in case of prior cardiac surgery requiring sternotomy we observed significantly reduced early graft and patient survival (57.00 and 94.09 months, respectively) when compared to patients undergoing solitary KTx (183.08 and 192.71 months; p < 0.001, respectively) or HKTx without prior cardiac surgery (203.22 and 203.22 months; p = 0.016 and p = 0.019, respectively), most probably explained by the significantly increased rate of primary nonfunction (33.3%) and in-hospital mortality (25.0%).

CONCLUSIONS

Our data demonstrates the increased rate of early kidney graft loss and thus significantly inferior graft survival in high-risk patients undergoing HKTx. Thus, we advocate for a "kidney-after-heart" program in such patients to ensure responsible and reasonable utilization of scarce resources in times of ongoing organ shortage crisis.

A review of liver dysfunction in the lung transplant patient

Liver dysfunction is an increasingly common finding in patients evaluated for lung transplantation. New or worsening dysfunction in the perioperative period, defined by presence of clinical ascites/encephalopathy, high model for end-stage liver disease (MELD) score, and/or independent diagnostic criteria, is associated with high short- and long-term mortality. Therefore, a thorough liver function assessment is necessary prior to listing for lung transplant. Unfortunately, identification and intraoperative monitoring remain the only options for prevention of disease progression with isolated lung transplantation. Combined lung and liver transplantation may provide an option for definitive long-term management in selecting patients with known liver disease at high risk for postoperative progression. However, experience with the combined operation is extremely limited and indications for combined lung and liver transplant remain unclear. Herein, we present a comprehensive literature review of patients with liver dysfunction undergoing lung transplantation with and without concurrent liver transplant in an effort to illuminate the risks, benefits, and clinical judgement surrounding decision to pursue combined lung-liver transplantation (CLLT). We also argue description of liver function is currently a weakness of the current lung allocation scoring system. Additional algorithms incorporating liver function may aid in risk stratification and decision to pursue combined transplantation.

Impaired ATG16L-Dependent Autophagy Promotes Renal Interstitial Fibrosis in Chronic Renal Graft Dysfunction Through Inducing EndMT by NF-κB Signal Pathway

Chronic renal graft dysfunction (CAD) is caused by multiple factors, including glomerular sclerosis, inflammation, interstitial fibrosis and tubular atrophy (IF/TA). However, the most prominent elements of CAD are IF/TA. Our studies have confirmed that endothelial-mesenchymal transition (EndMT) is an important source to allograft IF/TA. The characteristic of EndMT is the loss of endothelial marker and the acquisition of mesenchymal or fibroblastic phenotypes. Autophagy is an intracellular degradation pathway that is regulated by autophagy-related proteins and plays a vital role in many fibrotic conditions. However, whether or not autophagy contributes to fibrosis of renal allograft and how such mechanism occurs still remains unclear. Autophagy related 16 like gene (ATG16L) is a critical autophagy-related gene (ARG) necessary for autophagosome formation. Here, we first analyzed kidney transplant patient tissues from Gene Expression Omnibus (GEO) datasets and 60 transplant patients from our center. Recipients with stable kidney function were defined as non-CAD group and all patients in CAD group were histopathologically diagnosed with CAD. Results showed that ATG16L, as one significant differential ARG, was less expressed in CAD group compared to the non-CAD group. Furthermore, we found there were less autophagosomes and autolysosomes in transplanted kidneys of CAD patients, and downregulation of autophagy is a poor prognostic factor. In vitro, we found out that the knockdown of ATG16L enhanced the process of EndMT in human renal glomerular endothelial cells (HRGECs). In vivo, the changes of EndMT and autophagic flux were then detected in rat renal transplant models of CAD. We demonstrated the occurrence of EndMT, and indicated that abundance of ATG16L was accompanied by the dynamic autophagic flux change along different stages of kidney transplantation. Mechanistically, knockdown of ATG16L, specifically in endothelial cells, reduced of NF-κB degradation and excreted inflammatory cytokines (IL-1β, IL-6 and TNF-α), which could facilitate EndMT. In conclusion, ATG16L-dependent autophagic flux causing by transplant showed progressive loss increase over time. Inflammatory cytokines from this process promoted EndMT, thereby leading to progression of CAD. ATG16L served as a negative regulator of EndMT and development of renal graft fibrosis, and autophagy can be explored as a potential therapeutic target for chronic renal graft dysfunction.

Long-term outcomes after kidney transplant failure and variables related to risk of death and probability of retransplant: Results from a single-center cohort study in Brazil

Background

Returning to dialysis after kidney graft loss (GL) is associated with a high risk of mortality, mainly in the first 3–6 months. The follow-up of patients with GL should be extended to better understand crude patient outcomes, mainly in emerging countries, where the transplantation activity has increased.

Methods

This is a historical single-center cohort study conducted in an emerging country (Brazil) that included 115 transplant patients with kidney allograft failure who were followed for 44.1 (21.4; 72.6) months after GL. The outcomes were death or retransplantation after GL calculated by Kaplan-Meier and log-rank tests. Proportional hazard ratios for death and retransplantation were assessed by Cox regression.

Results

The 5-year probability of retransplantation was 38.7% (95% CI: 26.1%-51.2%) and that of death was 37.7% (95% CI: 24.9%-50.5%); OR = 1.03 (95% CI: 0.71–1.70) and P = 0.66. The likelihood of retransplantation was higher in patients who resumed dialysis with higher levels of hemoglobin (HR = 1.22; 95% CI = 1.04–1.43; P = 0.01) and lower in blood type O patients (HR = 0.48; 95% CI = 0.25–0.93; P = 0.03), which was associated with a lower frequency of retransplantation with a subsequent living-donor kidney. On the other hand, the risk of death was significantly associated with Charlson comorbidity index (HR for each point = 1.37; 95% CI 1.19–1.50; P<0.001), and residual eGFR at the time when patients had resumed to dialysis (HR for each mL = 1.14; 95% CI = 1.05–1.25; P = 0.002). The trend toward a lower risk of death when patients had resumed to dialysis using AV fistula access was observed (HR = 0.50; 95% CI 0.25–1.02; P = 0.06), while a higher risk seems to be associated with the number of previous engraftment (HR = 2.01; 95% CI 0.99–4.07; P = 0.05).

Conclusions

The 5-year probability of retransplantation was not less than that of death. Variables related to the probability of retransplantation were hemoglobin level before resuming dialysis and ABO blood type, while the risk of death was associated with comorbidities and residual eGFR.

The Irish experience of kidney transplantation among recipients with prior non-renal solid organ transplants: A retrospective study on short- and long-term outcomes

BACKGROUND

This study aims to evaluate allograft and patient outcomes among recipients of kidney transplants after non-renal solid organ transplants. We also aim to compare our findings with recipients of a repeat kidney transplant.

METHODS

We performed an analysis on kidney transplant recipients who underwent kidney transplantation after a non-renal solid organ transplant. Survival data were stratified into 2 groups: Group A (n = 37) consisted of recipients of a kidney transplant after prior non-renal solid organ transplant, and Group B (n = 330) consisted of recipients of a repeat kidney transplant.

RESULTS

The 1-,5-, and 10-year graft survival (death-censored) for recipients of a kidney transplant post-non-renal solid organ transplant (Group A) were 97.3%, 91.5%, and 86.9%, compared with 97.9%, 90.2%, and 83.4% for recipients of a repeat kidney transplant (Group B) (p = .32). The 1-, 5-, and 10-year patient survival rates were 97.3%, 82.7%, and 79.1% in Group A compared to 97.9%, 90.2%, and 83.4% in Group B. Unadjusted overall patient survival was significantly lower for Group A (p = .017).

CONCLUSION

Kidney transplant recipients who have undergone a previous non-renal solid organ transplant have similar allograft survival outcomes, but higher long-term mortality rates compared to repeat kidney transplant recipients.

Predictors of long-term renal allograft survival after second kidney transplantation

INTRODUCTION

Few studies investigate significant perioperative predictors for long-term renal allograft survival after second kidney transplant (SKT). We compared long-term survival following SKT with primary kidney transplant and determined predictors of renal allograft failure after SKT.

METHODS

Outcomes of all primary or second kidney transplant recipients at a national kidney transplant center between 1993 and 2017 were reviewed. The primary outcomes measurements were renal allograft survival for both first and second kidney transplants. Secondary outcome measurements were incidence of delayed graft function (DGF), incidence of acute rejection (AR), and predictors for renal allograft survival in SKT recipients.

RESULTS

In total, there were 392 SKTs and 2748 primary kidney transplants performed between 1993 and 2017. The 1-, 5-, and 10-year death-censored graft survival for deceased-donor recipients was 95.3%, 88.7%, and 78.2% for primary kidney transplant and 94.9%, 87.1%, and 74.9% for SKT (P = .0288). Survival of primary renal allograft <6 years (HR 0.6, P = .017), AR episodes (HR 1.6, P = .031), DGF (HR 2.0, P = .005), and HLA-DR MM (HR 1.7, P = .018) was independent predictors of long-term renal allograft failure after SKT.

CONCLUSION

These findings may provide important information on long-term survival outcomes after SKT and for identifying patients at risk for long-term renal allograft failure after SKT.

Long-Term Redistribution of Peripheral Lymphocyte Subpopulations after Switching from Calcineurin to mTOR Inhibitors in Kidney Transplant Recipients

Classical immunosuppression based on steroids, calcineurin inhibitors, and mycophenolate results in several unwanted effects and unsatisfactory long-term outcomes in kidney transplantation (KT). New immunosuppressors search for fewer adverse events and increased graft survival but may have a distinct impact on graft function and immunological biomarkers according to their mechanism of action. This prospective study evaluates the immunological effect of tacrolimus to serine/threonine protein kinase mechanistic target of rapamycin inhibitors (mTORi) conversion in 29 KT recipients compared with 16 controls maintained on tacrolimus. We evaluated renal function, human leukocyte antigen (HLA) antibodies and peripheral blood lymphocyte subsets at inclusion and at 3, 12, and 24 months later. Twenty immunophenotyped healthy subjects served as reference. Renal function remained stable in both groups with no significant change in proteinuria. Two patients in the mTORi group developed HLA donor-specific antibodies and none in the control group (7% vs. 0%, p = 0.53). Both groups showed a progressive increase in regulatory T cells, more prominent in patients converted to mTORi within the first 18 months post-KT (p < 0.001). All patients showed a decrease in naïve B cells (p < 0.001), excepting those converted to mTORi without receiving steroids (p = 0.31). Transitional B cells significantly decreased in mTORi patients (p < 0.001), independently of concomitant steroid treatment. Finally, CD56^bright and CD94/NK group 2 member A receptor positive (NKG2A⁺) Natural Killer (NK) cell subsets increased in mTORi- compared to tacrolimus-treated patients (both p < 0.001). Patients switched to mTORi displayed a significant redistribution of peripheral blood lymphocyte subpopulations proposed to be associated with graft outcomes. The administration of steroids modified some of these changes.

Kidney Transplantation in Patients With Chronic Kidney Disease After a Previous Lung Transplantation

BACKGROUND

The development of chronic kidney disease is a common complication after a lung transplantation, especially since the introduction of immunosuppressive treatments based on calcineurin inhibitors. Many of these patients reach end-stage renal disease and even need renal replacement therapy. Among the different options of renal replacement therapy, we consider kidney transplantation as a feasible option for these patients.

METHODS

A single center, observational retrospective study including 8 lung transplanted patients who have received a kidney transplant in the period between 2013 and 2017 with at least 1 year of follow-up was used.

RESULTS

Seven patients maintained an adequate function of the graft 1 year after kidney transplantation, and 1 patient died because of a pulmonary condition in spite of a previous kidney transplant. Two patients presented delayed graft function in the first days after surgery.

CONCLUSIONS

The kidney transplantation is a technique of renal replacement therapy that should be considered in patients with previous lung transplantation. Experienced centers in double sequential lung and kidney transplantation should be established to assess and treat these types of patients.

Trends in the Causes of Death among Kidney Transplant Recipients in the United States (1996-2014)

BACKGROUND

Death with graft function remains an important cause of graft loss among kidney transplant recipients (KTRs). Little is known about the trend of specific causes of death in KTRs in recent years.

METHODS

We analyzed United States Renal Data System data (1996-2014) to determine 1- and 10-year all-cause and cause-specific mortality in adult KTRs who died with a functioning allograft. We also studied 1- and 10-year trends in the various causes of mortality.

RESULTS

Of 210,327 KTRs who received their first kidney transplant from 1996 to 2014, 3.2% died within 1 year after transplant. Cardiovascular deaths constituted the majority (24.7%), followed by infectious (15.2%) and malignant (2.9%) causes; 40.1% of deaths had no reported cause. Using 1996 as the referent year, all-cause as well as cardiovascular mortality declined, whereas mortality due to malignancy did not. For analyses of 10-year mortality, we studied 94,384 patients who received a first kidney transplant from 1996 to 2005. Of those, 22.1% died over 10 years and the causative patterns of their causes of death were similar to those associated with 1-year mortality.

CONCLUSIONS

Despite the downtrend in mortality over the last 2 decades, a significant percentage of KTRs die in 10-years with a functioning graft, and cardiovascular mortality remains the leading cause of death. These data also highlight the need for diligent collection of mortality data in KTRs.