OPTN/SRTR 2016 Annual Data Report: Kidney

Deceased donor urinary DKK3 associates with future allograft function following kidney transplantation

Predicting future kidney allograft function is challenging. Novel biomarkers, such as urinary Dickkopf-3 (uDKK3), may help guide donor selection and improve allograft outcomes. In this prospective multicenter pilot trial, we investigated whether donor uDKK3 reflects organ quality and is associated with future allograft function. We measured uDKK3/creatinine ratios (uDKK3/crea) from 95 deceased and 46 living kidney donors. Pre-nephrectomy uDKK3/crea levels were 100x higher in deceased than in living donors (9888 pg/mg versus 113 pg/mg, p<0.001). Among deceased donor transplantations, recipients were stratified by their corresponding uDKK3/crea donor levels ranging below (group A, n=68) or above (group B, n=65) median. The primary endpoint of best estimated glomerular filtration rate (eGFR) within the first 3 months after kidney transplantation was superior in group A (56.3 ml/min/1.73 m2) compared to group B (44.2 ml/min/1.73 m2, p=0.0139). Second, the composite clinical endpoint consisting of death, allograft failure or eGFR decline >50% occurred less frequent in group A. By mixed linear regression modelling, donor uDKK3/crea remained an independent predictor of eGFR after transplantation, with a slope of -4.282 ml/min/1.73 m2 per logarithmic increase in donor uDKK3/crea. In summary, urinary DKK3 may serve as a non-invasive, donor-dependent biomarker for assessing organ quality and future allograft function.

Nitric oxide protects intestinal mucosal barrier function and prevents acute graft rejection after intestinal transplantation: A mini-review

Intestinal transplantation is a complex technical procedure that provides patients suffering from end-stage intestinal failure an opportunity to enjoy improved quality of life, nutrition and survival. Compared to other types of organ transplants, it is a relatively new advancement in the field of organ transplantation. Nevertheless, great advances have been made over the past few decades to the present era, including the use of ischemic preconditioning, gene therapy, and addition of pharmacological supplements to preservation solutions. However, despite these strides, intestinal transplantation is still a challenging endeavor due to several factors. Notable among them is ischemia-reperfusion injury (IRI), which results in loss of cellular integrity and mucosal barrier function. In addition, IRI causes graft failure, delayed graft function, and decreased graft and recipient survival. This has necessitated the search for novel therapeutic avenues and improved transplantation protocols to prevent or attenuate intestinal IRI. Among the many candidate agents that are being investigated to combat IRI and its associated complications, nitric oxide (NO). NO is an endogenously produced gaseous signaling molecule with several therapeutic properties. The purpose of this mini-review is to discuss IRI and its related complications in intestinal transplantation, and NO as an emerging pharmacological tool against this challenging pathological condition. i.

Lymphotoxin β receptor and tertiary lymphoid organs shape acute and chronic allograft rejection

Solid organ transplantation remains the life-saving treatment for end-stage organ failure, but chronic rejection remains a major obstacle to long-term allograft outcomes and has not improved substantially. Tertiary lymphoid organs (TLOs) are ectopic lymphoid structures that form under conditions of chronic inflammation, and evidence from human transplantation suggests that TLOs regularly form in allografts undergoing chronic rejection. In this study, we utilized a mouse renal transplantation model and manipulation of the lymphotoxin αβ/lymphotoxin β receptor (LTαβ/LTβR) pathway, which is essential for TLO formation, to define the role of TLOs in transplantation. We showed that intragraft TLOs are sufficient to activate the alloimmune response and mediate graft rejection in a model where the only lymphoid organs are TLOs in the allograft. When transplanted to recipients with a normal set of secondary lymphoid organs, the presence of graft TLOs or LTα overexpression accelerated rejection. If the LTβR pathway was disrupted in the donor graft, TLO formation was abrogated, and graft survival was prolonged. Intravital microscopy of renal TLOs demonstrated that local T and B cell activation in TLOs is similar to that observed in secondary lymphoid organs. In summary, we demonstrated that immune activation in TLOs contributes to local immune responses, leading to earlier allograft failure. TLOs and the LTαβ/LTβR pathway are therefore prime targets to limit local immune responses and prevent allograft rejection. These findings are applicable to other diseases, such as autoimmune diseases or tumors, where either limiting or boosting local immune responses is beneficial and improves disease outcomes.

CCR7 and CD48 as Predicted Targets in Acute Rejection Related to M1 Macrophage after Pediatric Kidney Transplantation

Background

Kidney transplantation (KT) is the best treatment for end-stage renal disease. Although long and short-term survival rates for the graft have improved significantly with the development of immunosuppressants, acute rejection (AR) remains a major risk factor attacking the graft and patients. The innate immune response plays an important role in rejection. Therefore, our objective is to determine the biomarkers of congenital immunity associated with AR after KT and provide support for future research.

Materials and Methods

A differential expression genes (DEGs) analysis was performed based on the dataset GSE174020 from the NCBI gene Expression Synthesis Database (GEO) and then combined with the GSE5099 M1 macrophage-related gene identified in the Molecular Signatures Database. We then identified genes in DEGs associated with M1 macrophages defined as DEM1Gs and performed gene ontology (GO) and Kyoto Encyclopedia of Genomes (KEGG) enrichment analysis. Cibersort was used to analyze the immune cell infiltration during AR. At the same time, we used the protein-protein interaction (PPI) network and Cytoscape software to determine the key genes. Dataset, GSE14328 derived from pediatric patients, GSE138043 and GSE9493 derived from adult patients, were used to verify Hub genes. Additional verification was the rat KT model, which was used to perform HE staining, immunohistochemical staining, and Western Blot. Hub genes were searched in the HPA database to confirm their expression. Finally, we construct the interaction network of transcription factor (TF)-Hub genes and miRNA-Hub genes.

Results

Compared to the normal group, 366 genes were upregulated, and 423 genes were downregulated in the AR group. Then, 106 genes related to M1 macrophages were found among these genes. GO and KEGG enrichment analysis showed that these genes are mainly involved in cytokine binding, antigen binding, NK cell-mediated cytotoxicity, activation of immune receptors and immune response, and activation of the inflammatory NF-κB signaling pathway. Two Hub genes, namely CCR7 and CD48, were identified by PPI and Cytoscape analysis. They have been verified in external validation sets, originated from both pediatric patients and adult patients, and animal experiments. In the HPA database, CCR7 and CD48 are mainly expressed in T cells, B cells, macrophages, and tissues where these immune cells are distributed. In addition to immunoinfiltration, CD4+T, CD8+T, NK cells, NKT cells, and monocytes increased significantly in the AR group, which was highly consistent with the results of Hub gene screening. Finally, we predicted that 19 TFs and 32 miRNAs might interact with the Hub gene.

Conclusions

Through a comprehensive bioinformatic analysis, our findings may provide predictive and therapeutic targets for AR after KT.

Impacts of Pre-transplant Panel-Reactive Antibody on Post-transplantation Outcomes: A Study of Nationwide Heart Transplant Registry Data

BACKGROUND AND OBJECTIVES

The number of sensitized heart failure patients on waiting lists for heart transplantation (HTx) is increasing. Using the Korean Organ Transplantation Registry (KOTRY), a nationwide multicenter database, we investigated the prevalence and clinical impact of calculated panel-reactive antibody (cPRA) in patients undergoing HTx.

METHODS

We retrospectively reviewed 813 patients who underwent HTx between 2014 and 2021. Patients were grouped according to peak PRA level as group A: patients with cPRA ≤10% (n= 492); group B: patients with cPRA >10%, <50% (n=160); group C patients with cPRA ≥50% (n=161). Post-HTx outcomes were freedom from antibody-mediated rejection (AMR), acute cellular rejection, coronary allograft vasculopathy, and all-cause mortality.

RESULTS

The median follow-up duration was 44 (19-72) months. Female sex, re-transplantation, and pre-HTx renal replacement therapy were independently associated with an increased risk of sensitization (cPRA ≥50%). Group C patients were more likely to have longer hospital stays and to use anti-thymocyte globulin as an induction agent compared to groups A and B. Significantly more patients in group C had positive flow cytometric crossmatch and had a higher incidence of preformed donor-specific antibody (DSA) compared to groups A and B. During follow-up, group C had a significantly higher rate of AMR, but the overall survival rate was comparable to that of groups A and B. In a subgroup analysis of group C, post-transplant survival was comparable despite higher preformed DSA in a desensitized group compared to the non-desensitized group.

CONCLUSIONS

Patients with cPRA ≥50% had significantly higher incidence of preformed DSA and lower freedom from AMR, but post-HTx survival rates were similar to those with cPRA <50%. Our findings suggest that sensitized patients can attain comparable post-transplant survival to non-sensitized patients when treated with optimal desensitization treatment and therapeutic intervention.

Use of Federal Reimbursement for Living Donor Costs by Racial and Ethnic Minorities: Implications for Disparities in Access to Living Donor Transplantation

BACKGROUND

Minority race, ethnicity, and financial barriers are associated with lower rates of living donor (LD) kidney transplantation (LDKT). Financial reimbursement for LD costs may impact social determinants of health and, therefore, impact disparities in access to LDKT.

METHODS

Among US LDKTs, we studied associations between racial and ethnic minority status and utilization of the National Living Donor Assistance Center (NLDAC), a means-tested reimbursement program for nonmedical LD costs. We analyzed demographic, clinical, income, and survey data from NLDAC and the Scientific Registry of Transplant Recipients (January 1, 2011, to December 31, 2022) to identify predictors of NLDAC utilization.

RESULTS

Among 70 069 US LDKTs, 6093 NLDAC applicants were identified (9% of US LDKTs). Racial and ethnic minorities were over-represented in NLDAC-supported LDKTs compared with non-NLDAC US LDKTs (Black donors 12% versus 9%; Black recipients 15% versus 12%; Hispanic donors 21% versus 14%; Hispanic recipients 23% versus 15%; all P < 0.001). Among preemptive transplants, use of NLDAC by donors to Hispanic recipients (11%) was nearly twice as high as that of non-Hispanic recipients (6%) (P < 0.001). At time of NLDAC application, 72% stated NLDAC "will make it possible" to donate; higher proportions of minority applicants agreed (Black 80%, White 70%, P < 0.001; Hispanic 79%, non-Hispanic 70%, P < 0.001). Racial and ethnic minority-concordant transplants were significantly more likely to use NLDAC (donor/recipient: Black/Black risk-adjusted odds ratio [OR], 1.85, other/other OR 2.59, Hispanic/Hispanic OR 1.53; all P < 0.05).

CONCLUSIONS

Reduction of LD financial barriers may increase access to LDKT, particularly in racial and ethnic minority communities.

Screening of novel biomarkers for acute kidney transplant rejection using DIA-MS based proteomics

BACKGROUND

Kidney transplantation is the preferred treatment for patients with end-stage renal disease. However, acute rejection poses a threat to the graft long-term survival. The aim of this study was to identify novel biomarkers to detect acute kidney transplant rejection.

METHODS

The serum proteomic profiling of kidney transplant patients with T cell-mediated acute rejection (TCMR) and stable allograft function (STA) was analyzed using data-independent acquisition mass spectrometry (DIA-MS). The differentially expressed proteins (DEPs) of interest were further verified by enzyme-linked immunosorbent assay (ELISA).

RESULTS

A total of 131 DEPs were identified between STA and TCMR patients, 114 DEPs were identified between mild and severe TCMR patients. The verification results showed that remarkable higher concentrations of serum amyloid A protein 1 (SAA1) and insulin like growth factor binding protein 2 (IGFBP2), and lower fetuin-A (AHSG) concentration were found in TCMR patients when compared with STA patients. We also found higher SAA1 concentration in severe TCMR group when compared with mild TCMR group. The receiver operating characteristics (ROC) analysis further confirmed that combination of SAA1, AHSG, and IGFBP2 had excellent performance in the acute rejection diagnosis.

CONCLUSIONS

Our data demonstrated that serum SAA1, AHSG, and IGFBP2 could be effective biomarkers for diagnosing acute rejection after kidney transplantation. DIA-MS has great potential in biomarker screening of kidney transplantation.

Impact of Switching From Immediate- or Prolonged-Release to Once-Daily Extended-Release Tacrolimus (LCPT) on Tremor in Stable Kidney Transplant Recipients: The Observational ELIT Study

Once-daily extended-release tacrolimus (LCPT) exhibits increased bioavailability versus immediate-release (IR-TAC) and prolonged release (PR-TAC) tacrolimus. Improvements in tremor were previously reported in a limited number of kidney transplant patients who switched to LCPT. We conducted a non-interventional, non-randomized, uncontrolled, longitudinal, prospective, multicenter study to assess the impact of switching to LCPT on tremor and quality of life (QoL) in a larger population of stable kidney transplant patients. The primary endpoint was change in The Essential Tremor Rating Assessment Scale (TETRAS) score; secondary endpoints included 12-item Short Form Survey (SF-12) scores, tacrolimus trough concentrations, neurologic symptoms, and safety assessments. Subgroup analyses were conducted to assess change in TETRAS score and tacrolimus trough concentration/dose (C0/D) ratio by prior tacrolimus formulation and tacrolimus metabolizer status. Among 221 patients, the mean decrease of TETRAS score after switch to LCPT was statistically significant (p < 0.0001 vs. baseline). There was no statistically significant difference in change in TETRAS score after switch to LCPT between patients who had received IR-TAC and those who had received PR-TAC before switch, or between fast and slow metabolizers of tacrolimus. The overall increase of C0/D ratio post-switch to LCPT was statistically significant (p < 0.0001) and from baseline to either M1 or M3 (both p < 0.0001) in the mITT population and in all subgroups. In the fast metabolizers group, the C0/D ratio crossed over the threshold of 1.05 ng/mL/mg after the switch to LCPT. Other neurologic symptoms tended to improve, and the SF-12 mental component summary score improved significantly. No new safety concerns were evident. In this observational study, all patients had a significant improvement of tremor, QoL and C0/D ratio post-switch to LCPT irrespective of the previous tacrolimus formulation administered (IR-TAC or PR-TAC) and irrespective from their metabolism status (fast or slow metabolizers).

Spatiotemporal immune atlas of a clinical-grade gene-edited pig-to-human kidney xenotransplant

Pig-to-human xenotransplantation is rapidly approaching the clinical arena; however, it is unclear which immunomodulatory regimens will effectively control human immune responses to pig xenografts. Here, we transplant a gene-edited pig kidney into a brain-dead human recipient on pharmacologic immunosuppression and study the human immune response to the xenograft using spatial transcriptomics and single-cell RNA sequencing. Human immune cells are uncommon in the porcine kidney cortex early after xenotransplantation and consist of primarily myeloid cells. Both the porcine resident macrophages and human infiltrating macrophages express genes consistent with an alternatively activated, anti-inflammatory phenotype. No significant infiltration of human B or T cells into the porcine kidney xenograft is detectable. Altogether, these findings provide proof of concept that conventional pharmacologic immunosuppression may be able to restrict infiltration of human immune cells into the xenograft early after compatible pig-to-human kidney xenotransplantation.

Effect of Different Induction Immunosuppression on the Incidence of Infectious Complications after Kidney Transplantation-Single Center Study

Background/Objectives: Potent immunosuppression lowers the incidence of acute graft rejection but increases the risk of infections. In order to decrease either infectious complications or acute rejection, it is necessary to identify risk groups of patients profiting from personalized induction immunosuppressive treatment. The aim of our analysis was to find whether there were higher incidences of infectious complications after kidney transplantation (KT) in groups with different induction immunosuppressive treatment and also to find independent risk factors for recurrent infections. Materials: We retrospectively evaluated all patients with induction treatment with basiliximab after kidney transplantation from 2014 to 2019 at our center relative to age- and sex-matched controls of patients with thymoglobulin induction immunosuppression. Results: Our study consisted of two groups: basiliximab (39) and thymoglobulin (39). In the thymoglobulin group we observed an increased incidence of recurrent infection in every observed interval; however, acute rejection was seen more often in the basiliximab group. A history of respiratory diseases and thrombocytopenia were identified as independent risk factors for recurrent bacterial infections from the first to sixth month after KT. Decreased eGFR from the first month, infections caused by multi-drug-resistant bacteria, and severe infections (reflected by the need for hospitalization) were identified as independent risk factors for recurrent bacterial infections from the first to the twelfth month after KT. Conclusions: We found that in the group of patients with thymoglobulin induction immunosuppressive treatment, infectious complications occurred significantly more often during the entire monitored period with decreased incidence of acute humoral and cellular rejection occurred more often.

Barriers and Facilitators to Exercise in Older Adults Awaiting Kidney Transplantation and Their Care Partners

Rationale & Objective

Despite guidelines calling to improve physical activity in older adults, and evidence suggesting that prekidney transplant physical function is highly associated with posttransplant outcomes, only a small percentage of older patients treated with dialysis are engaged in structured exercise. We sought to elucidate barriers and facilitators of exercise among older adults treated with dialysis awaiting transplant and their care partners.

Study Design

Individual, in-depth, cognitive interviews were conducted separately for patients and care partners through secure web-conferencing.

Setting & Participants

Twenty-three patients (≥50 years of age, treated with dialysis from the University of San Francisco kidney transplantation clinic, with a short physical performance battery of ≤10) and their care partners.

Analytical Approach

All audio interviews were transcribed verbatim. Three investigators independently coded data and performed qualitative thematic content. The interview guide was updated iteratively based on the Capability Opportunity Motivation Behavior model.

Results

Patients' median age was 60 years (57 ± 63.5) and care partners' median ages was 57 years (49.5 ± 65.5). Thirty-nine percent of patients and 78% of care partners were female, 39% of patients and 30% of care partners self-identified as African American, and 47% of dyads were spouse or partner relationships. Major themes for barriers to pretransplant exercise included lack of understanding of an appropriate regimen, physical impairments, dialysis schedules, and safety concerns. Major facilitators included having individualized or structured exercise programs, increasing social support for patients and care partners, and motivation to regain independence or functionality or to promote successful transplantation.

Limitations

Participants geographically limited to Northern California.

Conclusions

Although patients and care partners report numerous barriers to pretransplant exercise and activity, they also reported many facilitators. An individualized, structured, home-based exercise program could circumvent many of the reported barriers and allow older patients to improve pretransplant physical function.

Donor and recipient risk factors for the development of primary graft dysfunction following lung transplantation

Primary Graft Dysfunction (PGD) is a major cause of both short-term and long-term morbidity and mortality following lung transplantation. Various donor, recipient, and technical risk factors have been previously identified as being associated with the development of PGD. Here, we present a comprehensive review of the current literature as it pertains to PGD following lung transplantation, as well as discussing current strategies to mitigate PGD and future directions. We will pay special attention to recent advances in lung transplantation such as ex-vivo lung perfusion, thoracoabdominal normothermic regional perfusion, and up-to-date literature published in the interim since the 2016 ISHLT consensus statement on PGD and the COVID-19 pandemic.

Impact of race-neutral eGFR calculations on African American kidney transplant candidate wait time: A single center retrospective analysis

Race-inclusive estimated glomerular filtration rate (eGFR) could contribute to racial disparity in access to kidney transplantation. The Organ Procurement and Transplantation Network (OPTN) issued a policy allowing waiting time modification for candidates affected by race-inclusive eGFR calculations. Implementation of the new OPTN policy at the kidney transplant program of the Mount Sinai Hospital involved review of 921 African American candidates, of whom 240 (26%) candidates gained a median of 1 year and 10 months. The duration of time candidates gained varied from a minimum of 5 days to a maximum of 12 years and 3 months; 45.4% gained at least 2 years, and 12% gained at least 4 years of wait time. Among those who gained wait time, 20 (8.3%) candidates received deceased donor kidney transplants. Candidates who gained wait time had similar sociodemographic characteristics as those who did not, except that the median age for the former was higher by 3 years (59 vs. 56). Our early data suggest that the current policy on waiting time modification for candidates affected by race-inclusive estimation of GFR has the potential to improve racial disparity in access to kidney transplantation. However, the generalizability of our findings to other centers requires further study.

The Significance of Major Histocompatibility Complex Class I Chain-related Molecule A in Solid Organ and Hematopoietic Stem Cell Transplantation: A Comprehensive Overview

Improving long-term allograft survival and minimizing recipient morbidity is of key importance in all of transplantation. Improved matching of classical HLA molecules and avoiding HLA donor-specific antibody has been a major focus; however, emerging data suggest the relevance of nonclassical HLA molecules, major histocompatibility complex class I chain-related gene A (MICA) and B, in transplant outcomes. The purpose of this review is to discuss the structure, function, polymorphisms, and genetics of the MICA molecule and relates this to clinical outcomes in solid organ and hematopoietic stem cell transplantation. The tools available for genotyping and antibody detection will be reviewed combined with a discussion of their shortcomings. Although data supporting the relevance of MICA molecules have accumulated, key knowledge gaps exist and should be addressed before widespread implementation of MICA testing for recipients pre- or posttransplantation.

Causes of death and associated factors with death after liver transplantation: a nationwide database study

BACKGROUND/AIMS

This study investigated overall, 1-year, and 5-year mortality rate, the causes of death, and associated factors with death in liver transplantation recipients.

METHODS

A total of 11,590 liver transplant recipients identified from National Health Insurance Service database between 2006 and 2017 were included. Factors associated with all-cause of death were analyzed by Cox proportional regression models. Cumulative mortality rate according to the underlying indication was estimated by Kaplan-Meier method.

RESULTS

The 12-year survival rate for all liver transplant recipients was 68%. In the overall, 1-year, and 5-year mortality of liver transplant recipients, hepatic death was the highest contributing risk, accounting for >65% of the causes of death. Deaths from cirrhosis and liver failure accounted for a high proportion of deaths within 1 year after transplantation, and deaths from malignant tumors such as hepatocellular carcinoma were high among late-stage deaths.

DISCUSSION

Although the most common cause of death from liver transplantation is due to primary disease, there was a difference in the pattern of major causes of death according to the period from transplantation to death. If appropriate medical intervention is performed at each period after transplantation, the survival rate can be improved.

Assessing Trans-Inhibition of OATP1B1 and OATP1B3 by Calcineurin and/or PPIase Inhibitors and Global Identification of OATP1B1/3-Associated Proteins

Organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 are key determinants of drug-drug interactions (DDIs). Various drugs including the calcineurin inhibitor (CNI) cyclosporine A (CsA) exert preincubation-induced trans-inhibitory effects upon OATP1B1 and/or OATP1B3 (abbreviated as OATP1B1/3) by unknown mechanism(s). OATP1B1/3 are phosphoproteins; calcineurin, which dephosphorylates and regulates numerous phosphoproteins, has not previously been investigated in the context of preincubation-induced trans-inhibition of OATP1B1/3. Herein, we compare the trans-inhibitory effects exerted on OATP1B1 and OATP1B3 by CsA, the non-analogous CNI tacrolimus, and the non-CNI CsA analogue SCY-635 in transporter-overexpressing human embryonic kidney (HEK) 293 stable cell lines. Preincubation (10-60 min) with tacrolimus (1-10 µM) rapidly and significantly reduces OATP1B1- and OATP1B3-mediated transport up to 0.18 ± 0.03- and 0.20 ± 0.02-fold compared to the control, respectively. Both CsA and SCY-635 can trans-inhibit OATP1B1, with the inhibitory effects progressively increasing over a 60 min preincubation time. At each equivalent preincubation time, CsA has greater trans-inhibitory effects toward OATP1B1 than SCY-635. Preincubation with SCY-635 for 60 min yielded IC50 of 2.2 ± 1.4 µM against OATP1B1, which is ~18 fold greater than that of CsA (0.12 ± 0.04 µM). Furthermore, a proteomics-based screening for protein interactors was used to examine possible proteins and processes contributing to OATP1B1/3 regulation and preincubation-induced inhibition by CNIs and other drugs. A total of 861 and 357 proteins were identified as specifically associated with OATP1B1 and OATP1B3, respectively, including various protein kinases, ubiquitin-related enzymes, the tacrolimus (FK506)-binding proteins FKBP5 and FKBP8, and several known regulatory targets of calcineurin. The current study reports several novel findings that expand our understanding of impaired OATP1B1/3 function; these include preincubation-induced trans-inhibition of OATP1B1/3 by the CNI tacrolimus, greater preincubation-induced inhibition by CsA compared to its non-CNI analogue SCY-635, and association of OATP1B1/3 with various proteins relevant to established and candidate OATP1B1/3 regulatory processes.

Anti-thymocyte globulin for treatment of T-cell-mediated allograft rejection

Anti-thymocyte globulin (ATG) is a pivotal immunosuppressive therapy utilized in the management of T-cell-mediated rejection and steroid-resistant rejection among renal transplant recipients. Commercially available as Thymoglobulin (rabbit-derived, Sanofi, United States), ATG-Fresenius S (rabbit-derived), and ATGAM (equine-derived, Pfizer, United States), these formulations share a common mechanism of action centered on their interaction with cell surface markers of immune cells, imparting immunosuppressive effects. Although the prevailing mechanism predominantly involves T-cell depletion via the com plement-mediated pathway, alternate mechanisms have been elucidated. Optimal dosing and treatment duration of ATG have exhibited variance across ran domised trials and clinical reports, rendering the establishment of standardized guidelines a challenge. The spectrum of risks associated with ATG administration spans from transient adverse effects such as fever, chills, and skin rash in the acute phase to long-term concerns related to immunosuppression, including susceptibility to infections and malignancies. This comprehensive review aims to provide a thorough exploration of the current understanding of ATG, encom passing its mechanism of action, clinical utility in the treatment of acute renal graft rejections, specifically steroid-resistant cases, efficacy in rejection episode reversal, and a synthesis of findings from different eras of maintenance immunosuppression. Additionally, it delves into the adverse effects associated with ATG therapy and its impact on long-term graft function. Furthermore, the review underscores the existing gaps in evidence, particularly in the context of the Banff classification of rejections, and highlights the challenges faced by clinicians when navigating the available literature to strike the optimal balance between the risks and benefits of ATG utilization in renal transplantation.

The role of efferocytosis and transplant rejection: Strategies in promoting transplantation tolerance using apoptotic cell therapy and/or synthetic particles

Recently, efforts have been made to recognize the precise reason(s) for transplant failure and the process of rejection utilizing the molecular signature. Most transplant recipients do not appreciate the unknown length of survival of allogeneic grafts with the existing standard of care. Two noteworthy immunological pathways occur during allogeneic transplant rejection. A nonspecific innate immune response predominates in the early stages of the immune reaction, and allogeneic antigens initiate a donor-specific adaptive reaction. Though the adaptive response is the major cause of allograft rejection, earlier pro-inflammatory responses that are part of the innate immune response are also regarded as significant in graft loss. The onset of the innate and adaptive immune response causes chronic and acute transplant rejection. Currently employed immunosuppressive medications have shown little or no influence on chronic rejection and, as a result, on overall long-term transplant survival. Furthermore, long-term pharmaceutical immunosuppression is associated with side effects, toxicity, and an increased risk of developing diseases, both infectious and metabolic. As a result, there is a need for the development of innovative donor-specific immunosuppressive medications to regulate the allorecognition pathways that induce graft loss and to reduce the side effects of immunosuppression. Efferocytosis is an immunomodulatory mechanism with fast and efficient clearance of apoptotic cells (ACs). As such, AC therapy strategies have been suggested to limit transplant-related sequelae. Efferocytosis-based medicines/treatments can also decrease the use of immunosuppressive drugs and have no detrimental side effects. Thus, this review aims to investigate the impact of efferocytosis on transplant rejection/tolerance and identify approaches using AC clearance to increase transplant viability.

The Long-Term Outcome of Kidney Transplant Recipients in the Eighth Decade Compared With Recipients in the Seventh Decade of Life

BACKGROUND

With the aging of the population, more older patients are being considered for kidney transplantation; therefore, it is crucial to evaluate the risks and benefits of transplantation in this population. This study aimed to assess long-term outcomes of kidney transplantation in a cohort of patients who underwent kidney transplantation at age >70 years, compared with patients aged 60 to 69 years at transplantation.

METHODS

Included in the study were 261 consecutive kidney transplant recipients: 52 were aged >70 years, and 209 were aged 60 to 69 years at transplantation. Data were collected retrospectively and analyzed using multivariate logistic regression to identify potential outcome risk factors.

RESULTS

The number of transplants in both groups increased during the study period. Mortality after transplantation was strongly correlated to age (hazard ratio [HR] = 1.11; 95% CI, 1.05-1.18; P < .001), deceased donor (HR = 2.0; 95% CI, 1.1-3.8; P = .034), and pretransplant diabetes (HR = 2.9; 95% CI, 1.7-4.9; P = .001). Recipients aged >70 years had an increased risk of death censored graft failure (HR = 2.98; 95% CI, 1.56-5.74; P = .001). In living donor transplants, 3-year survival was 80% in recipients age >70 years, compared with 98% in the 60- to 69-year group. Five-year survival was 71% and 92%, respectively. In deceased donor transplants, 3-year survival was 63% and 78%, and 5-year survival was 58% and 72%, respectively. The risk of malignancy (excluding nonmelanotic skin cancer) was nearly triple in the age >70 years group (HR = 2.96; 95% CI, 1.3-6.8; P = .01).

CONCLUSIONS

Patient and graft survival in kidney recipients in the eighth decade is worse compared with recipients in the seventh decade of life. However, it is improved with living kidney donation.

Machine Learning Model to Predict Graft Rejection After Kidney Transplantation

BACKGROUND

There are few predictive studies about early posttransplant outcomes taking into account baseline and posttransplant variables. The objective of this study was to create a predictive model for 30-day graft rejection using machine learning techniques.

METHODS

Retrospective study with 1255 patients undergoing transplant from living and deceased donors at a tertiary health service in Brazil. Recipient, donor, transplantation, and postoperative period data were collected from physical and electronic records. We split the data into derivation (training) and validation (test) datasets. Five supervised machine learning algorithms were developed with this subset of variables in the training set: Simple Logistic Regression, Lasso, Multilayer Perceptron, XGBoost, and Light GBM.

RESULTS

There were 147 (12.48%) cases of graft rejection within 30 days of transplantation. The best model was XGBoost (accuracy, 0.839; receiver operating characteristic area under the curve, 0.715; precision, 0.900). The model showed that deceased donor transplantation, glomerulopathy as an underlying disease, and donor's use of vasoactive drugs had more than 20% importance as rejection risk factors. The variables with the greatest predictive values were thymoglobulin induction and delayed graft function.

CONCLUSIONS

We fitted a machine learning model to predict 30-day graft rejection after kidney transplantation that reaches a higher accuracy and precision. Machine learning models could contribute to predicting kidney survival using nontraditional approaches.

Induction immunosuppression and post-transplant diabetes mellitus: a propensity-matched cohort study

Introduction

Post-transplant diabetes mellitus (PTDM) is a common complication among cardiac transplant recipients, causing diabetes-related complications and death. While certain maintenance immunosuppressive drugs increase PTDM risk, it is unclear whether induction immunosuppression can do the same. Therefore, we evaluated whether induction immunosuppression with IL-2 receptor antagonists, polyclonal anti-lymphocyte antibodies, or Alemtuzumab given in the peri-transplant period is associated with PTDM.

Methods

We used the Scientific Registry of Transplant Recipients database to conduct a cohort study of US adults who received cardiac transplants between January 2008-December 2018. We excluded patients with prior or multiple organ transplants and those with a history of diabetes, resulting in 17,142 recipients. We created propensity-matched cohorts (n=7,412) using predictors of induction immunosuppression and examined the association between post-transplant diabetes and induction immunosuppression by estimating hazard ratios using Cox proportional-hazards models.

Results

In the propensity-matched cohort, the average age was 52.5 (SD=13.2) years, 28.7% were female and 3,706 received induction immunosuppression. There were 867 incident cases of PTDM during 26,710 person-years of follow-up (32.5 cases/1,000 person-years). There was no association between induction immunosuppression and post-transplant diabetes (Hazard Ratio= 1.04, 95% confidence interval 0.91 - 1.19). Similarly, no associations were observed for each class of induction immunosuppression agents and post-transplant diabetes.

Conclusion

The use of contemporary induction immunosuppression in cardiac transplant patients was not associated with post-transplant diabetes.

Systemic inflammation early after kidney transplantation is associated with long-term graft loss: a cohort study

Background

Early graft loss following kidney transplantation is mainly a result of acute rejection or surgical complications, while long-term kidney allograft loss is more complex. We examined the association between systemic inflammation early after kidney transplantation and long-term graft loss, as well as correlations between systemic inflammation scores and inflammatory findings in biopsies 6 weeks and 1 year after kidney transplantation.

Methods

We measured 21 inflammatory biomarkers 10 weeks after transplantation in 699 patients who were transplanted between 2009 and 2012 at Oslo University Hospital, Rikshospitalet, Norway. Low-grade inflammation was assessed with predefined inflammation scores based on specific biomarkers: one overall inflammation score and five pathway-specific scores. Surveillance or indication biopsies were performed in all patients 6 weeks after transplantation. The scores were tested in Cox regression models.

Results

Median follow-up time was 9.1 years (interquartile range 7.6-10.7 years). During the study period, there were 84 (12.2%) death-censored graft losses. The overall inflammation score was associated with long-term kidney graft loss both when assessed as a continuous variable (hazard ratio 1.03, 95% CI 1.01-1.06, P = 0.005) and as a categorical variable (4th quartile: hazard ratio 3.19, 95% CI 1.43-7.10, P = 0.005). In the pathway-specific analyses, fibrogenesis activity and vascular inflammation stood out. The vascular inflammation score was associated with inflammation in biopsies 6 weeks and 1 year after transplantation, while the fibrinogenesis score was associated with interstitial fibrosis and tubular atrophy.

Conclusion

In conclusion, a systemic inflammatory environment early after kidney transplantation was associated with biopsy-confirmed kidney graft pathology and long-term kidney graft loss. The systemic vascular inflammation score correlated with inflammatory findings in biopsies 6 weeks and 1 year after transplantation.

Exploring the variable importance in random forests under correlations: a general concept applied to donor organ quality in post-transplant survival

Random Forests are a powerful and frequently applied Machine Learning tool. The permutation variable importance (VIMP) has been proposed to improve the explainability of such a pure prediction model. It describes the expected increase in prediction error after randomly permuting a variable and disturbing its association with the outcome. However, VIMPs measure a variable's marginal influence only, that can make its interpretation difficult or even misleading. In the present work we address the general need for improving the explainability of prediction models by exploring VIMPs in the presence of correlated variables. In particular, we propose to use a variable's residual information for investigating if its permutation importance partially or totally originates from correlated predictors. Hypotheses tests are derived by a resampling algorithm that can further support results by providing test decisions and p-values. In simulation studies we show that the proposed test controls type I error rates. When applying the methods to a Random Forest analysis of post-transplant survival after kidney transplantation, the importance of kidney donor quality for predicting post-transplant survival is shown to be high. However, the transplant allocation policy introduces correlations with other well-known predictors, which raises the concern that the importance of kidney donor quality may simply originate from these predictors. By using the proposed method, this concern is addressed and it is demonstrated that kidney donor quality plays an important role in post-transplant survival, regardless of correlations with other predictors.

Association of Three Different Dietary Approaches to Stop Hypertension Diet Indices with Renal Function in Renal Transplant Recipients

Several dietary indices assess the impacts of the Dietary Approaches to Stop Hypertension (DASH) diet on health outcomes. We explored DASH adherence and renal function among 85 Taiwanese renal transplant recipients (RTRs) in a cross-sectional study. Data collection included demographics, routine laboratory data, and 3-day dietary records. Three separate DASH indices, that defined by Camões (based on nine nutrients), that defined by Fung (using seven food groups and sodium), and that modified by Fung (as above but separated for men and women) were used. Renal function was ascertained through the estimated glomerular filtration rate (eGFR) from patients' medical records. Participants' mean age was 49.7 ± 12.6 years and eGFR was 54.71 ± 21.48 mL/min/1.73 m2. The three established DASH diet indices displayed significant correlations (r = 0.50-0.91) and indicated the nutritional adequacy of the diet. Multiple linear regressions indicated a significant positive association between higher DASH scores for each index and increased eGFR. In addition, RTRs in the highest DASH score tertile had higher eGFR rates than those in the lowest tertile, regardless of confounding variables. Adherence to a DASH-style diet correlated with better renal function among RTRs. Educating RTRs about the DASH diet may prevent graft function deterioration.

Lifetime Risk of Hepatorenal Events Assessed in Longitudinal Cohort of Renal Transplant Recipients with HBV Infection

BACKGROUND

Kidney transplantation is a treatment option for patients with end-stage renal disease (ESRD) who are infected with hepatitis B virus (HBV). However, the impact of nucleos(t)ide analogues usage on the clinical outcomes in HBV-infected ESRD patients undergoing kidney transplantation is not well understood. This study aimed to assess the outcomes of kidney transplant recipients with HBV infection using real-world data to provide insight into the disease course over time.

METHODS

A nationwide retrospective longitudinal population-level cohort study was conducted using the National Health Insurance Research Database. The study evaluated patient and allograft survival and kidney-related and liver-related events and identified factors contributing to these events.

RESULTS

Of the 4838 renal transplant recipients in the study, there were no significant differences in graft survival between the HBV-infected and non-infected groups (P = .244). However, the HBV-infected group had suboptimal patient survival compared to the non-infected group (hazard ratio [HR] for overall survival, 1.80; 95% CI 1.40-2.30; P < .001). Diabetes mellitus was associated with a higher re-dialysis rate (HR, 1.71; 95% CI, 1.38-2.12; P < .001) regarding kidney-associated events. For liver-associated events, HBV-infected status (HR, 9.40; 95% CI, 5.66-15.63; P < .001), and age >60 years (HR, 6.90; 95% CI, 3.14-15.19; P < .001) were associated with increased incidence of liver cancer.

CONCLUSIONS

Hepatitis B-infected renal transplant recipients have comparable graft survival but inferior patient survival outcomes due to pre-existing diseases and increasing liver-related complications. The findings of this study can help optimize treatment strategies and improve long-term outcomes for this patient population.

Value of conventional ultrasound and contrast-enhanced ultrasound for the assessment of renal allograft dysfunction and prognosis

BACKGROUND

Ultrasound (US) is the primary imaging modality for the assessment of transplanted kidneys. This study aims to investigate the ability of conventional US and contrast-enhanced US (CEUS) in assessing renal allograft function and prognosis.

METHODS

A total of 78 consecutive renal allograft recipients were enrolled. Patients were classified as normal allograft function (n = 41) and allograft dysfunction (n = 37) groups. All patients underwent US and parameters were measured. The independent-samples t-test or Mann-Whitney U test, logistic regression analysis, Kaplan-Meier survival plots, and Cox regression analysis were used.

RESULTS

In multivariable analysis, cortical echo intensity (EI) and cortical peak intensity (PI) were determinant US parameters for renal allograft dysfunction (p = .024 and p = .003, respectively). The combination of cortical EI and PI showed an area under the receiver operating characteristic curve (AUROC) of .785 (p < .001). Of 78 patients (median follow-up: 20mo), 16 (20.5%) exhibited composite end points. Cortical PI had a general prediction accuracy with an AUROC of .691, sensitivity of 87.5%, and specificity of 46.8% at the threshold of 22.08 dB in predicting prognosis (p = .019). The combination of estimated-glomerular filtration rate (e-GFR) and PI in predicting prognosis showed an AUROC of .845 with a cut-off value of .836, sensitivity of 84.0%, and specificity of 67.3% (p < .001).

CONCLUSION

This study indicates that cortical EI and PI are useful US parameters for evaluating renal allograft function and e-GFR combined with PI may provide a more accurate predictor of survival.

Feasibility of an implantable bioreactor for renal cell therapy using silicon nanopore membranes

The definitive treatment for end-stage renal disease is kidney transplantation, which remains limited by organ availability and post-transplant complications. Alternatively, an implantable bioartificial kidney could address both problems while enhancing the quality and length of patient life. An implantable bioartificial kidney requires a bioreactor containing renal cells to replicate key native cell functions, such as water and solute reabsorption, and metabolic and endocrinologic functions. Here, we report a proof-of-concept implantable bioreactor containing silicon nanopore membranes to offer a level of immunoprotection to human renal epithelial cells. After implantation into pigs without systemic anticoagulation or immunosuppression therapy for 7 days, we show that cells maintain >90% viability and functionality, with normal or elevated transporter gene expression and vitamin D activation. Despite implantation into a xenograft model, we find that cells exhibit minimal damage, and recipient cytokine levels are not suggestive of hyperacute rejection. These initial data confirm the potential feasibility of an implantable bioreactor for renal cell therapy utilizing silicon nanopore membranes.

Overview of pregnancy in solid-organ transplantation

PURPOSE OF REVIEW

Pregnancy in solid organ transplantation (SOT) is a very complex part of transplant medicine wherein there is scarce information available in the literature. Solid organ transplant recipients often have comorbidities, such as hypertension and diabetes, which add additional risk to a pregnancy.

RECENT FINDINGS

We present this review article on the various aspects of different types of immunosuppressant medications used in pregnancy with added inputs on contraception and fertility after transplant. We described the antepartum and postpartum considerations and discussed the adverse effects of the immunosuppressive medications. Maternal and fetal complications of each SOT have been also discussed in this article.

SUMMARY

This article will serve as the primary review articles for the use of immunosuppressive medications during pregnancy with consideration during pregnancy after SOT.

Age-related decline in anti-HBV antibodies in vaccinated kidney transplant recipients

BACKGROUND

Hepatitis B virus (HBV) vaccination is indicated for all end stage kidney disease patients, including all solid organ transplant candidates. Maintenance of adequate immunity is especially important for immunosuppressed solid organ recipients who are at increased risk for donor or community acquired HBV. The impact of age and immunosuppression on long-term maintenance of HBV immunity postvaccination has not been fully investigated.

METHODS

We performed a single-center retrospective study of 96 kidney transplant recipients, transplanted between July 2012 and December 2020, who had Hepatitis B surface antibody (HBsAb) levels measured pretransplantation and 1-year posttransplantation. We compared the change in HBsAb levels stratified by patient's age (<45, 45-60, and >60) and by whether or not the patient received lymphocyte depleting induction therapy.

RESULTS

Our results demonstrate that HBsAb IgG levels vary by age group, decreased significantly at 1-year posttransplant (p < .0001) and were significantly lower in the older cohort (p = .03). Among recipients who received rabbit anti-thymocyte globulin induction (rATG), the log HbsAb levels were significantly lower in the older age group (2.15 in age <45, 1.75 in age 45-60 and 1.47 in age >60, p = .01). Age group (p = .004), recipient HBcAb status (p = .002), and rATG (p = .048) were independently associated with >20% reduction in log HBsAb levels posttransplant.

CONCLUSION

Significant declines in HBsAb levels occur postkidney transplantation, especially in older individuals, thus placing exposed older kidney transplant recipients at greater risk of HBV infection and associated complications.

Kidney Allograft Monitoring by Combining Donor-Derived Cell-Free DNA and Molecular Gene Expression: A Clinical Management Perspective

Donor-derived cell-free DNA (dd-cfDNA) may safely assess kidney allograft rejection. Molecular Microscope (MMDx®) gene expression may offer increased precision to histology. This single-center retrospective study monitored kidney transplant recipients for rejection at specified time intervals by utilizing creatinine (SCr), proteinuria, donor-specific antibodies (DSAs), and dd-cfDNA. A clinically indicated biopsy sample was sent for histopathology and MMDx®. Patients were categorized into rejection (Rej) and non-rejection (NRej) groups, and further grouped according to antibody-mediated rejection (ABMR) subtypes. Rej and NRej groups included 52 and 37 biopsies, respectively. Median follow-up duration was 506 days. DSAs were positive in 53% and 22% of patients in both groups, respectively (p = 0.01). Among these groups, pre- and post-intervention median SCr, proteinuria, and dd-cfDNA at 1 month, 2 months, and at the last follow-up revealed significant difference for dd-cfDNA (all p = 0.01), however, no difference was found for SCr and proteinuria (p > 0.05). The AUC was 0.80 (95% CI: 0.69-0.91), with an optimal dd-cfDNA criterion of 2.2%. Compared to histology, MMDx® was more likely to diagnose ABMR (79% vs. 100%) with either C4d positivity or negativity and/or DSA positivity or negativity. Hence, a pre- and post-intervention allograft monitoring protocol in combination with dd-cfDNA, MMDx®, and histology has aided in early diagnosis and timely individualized intervention.

Choice of the Dialysis Modality: Practical Considerations

Chronic kidney disease and the need for kidney replacement therapy have increased dramatically in recent decades. Forecasts for the coming years predict an even greater increase, especially in low- and middle-income countries, due to the rise in metabolic and cardiovascular diseases and the aging population. Access to kidney replacement treatments may not be available to all patients, making it especially strategic to set up therapy programs that can ensure the best possible treatment for the greatest number of patients. The choice of the "ideal" kidney replacement therapy often conflicts with medical availability and the patient's tolerance. This paper discusses the pros and cons of various kidney replacement therapy options and their real-world applicability limits.

How Long Does It Take to Acquire Mastery of Performance in Laparoscopic Living Donor Nephrectomy? A Center-Based and Surgeon-Based Operative Time CUSUM Analysis

BACKGROUND

The safety of laparoscopic donor nephrectomy (LDN) has been widely documented, but its challenging learning curve (LC) requires an insightful assessment to expand its application. The aim of this study was to evaluate LC of LDN in a high-volume transplant center.

METHODS

Three hundred forty-three LDNs performed from 2001 to 2018 were evaluated. CUSUM analysis based on the operative time was used to assess the number of cases required to reach mastery in the technique for both the entire surgical team and for the 3 main surgeons considered separately. Analysis of association between demographics, perioperative characteristics, and complications within the different LC phases was conducted.

RESULTS

Mean operative time was 228.9 minutes. Mean length of stay was 3.8 days and mean warm ischemia time (WIT) was 170.8 seconds. Surgical and medical complication rates were 7.3% and 6.4%, respectively. The CUSUM-LC showed a requirement of 157 cases (for surgical team) and 75 cases (for single surgeons) to reach competence in the procedure. Patient baseline characteristic showed no differences among the LC phases. Compared with the initial LC phase, hospital stay was significantly lower at the end of the LC whereas WIT results were longer in the LC descendent phase.

CONCLUSIONS

This study confirms the safety and efficacy of LDN, with a low rate of complications. This analysis suggests that about 75 procedures are required to reach competence and 93 cases to achieve mastery level of skill for a single surgeon. It can be hypothesized that, in a high-volume transplant enter, the time to guarantee training in LDN is compatible with the duration of a clinical fellowship.

Early readmissions post kidney transplantation: lessons learned

INTRODUCTION

Kidney transplantation (KT) is the gold standard treatment for end-stage renal disease (ESRD) patients. Hospital readmissions post-transplant is a common complication and can be considered an indication of avoidable morbidity and hospital quality, and there is a significant correlation between EHR and adverse patient outcomes. This study aimed to assess the readmission rate following kidney transplants, the underlying causes, and possible ways to prevent it.

MATERIAL AND METHODS

We retrospectively reviewed the medical records of recipients from January 2016 to December 2021 in a single center. The primary objective of this study is to find the readmission rate for kidney transplants and the variables that contribute to readmission. Post-transplant complications that were resulted in the readmission categorized into surgical complications, graft-related complications, infections, DVT, and other medical complications.

RESULTS

Four hundred seventy-four renal allograft recipients met our inclusion criteria and were included in the study. 248 (52.3%) of the allograft recipients had at least one readmission during the first 90 days after the transplantation. 89 (18.8%) allograft recipients had more than one readmission episode in the first 90 days post-transplant. The perinephric fluid collection was the most common surgical complication (52.4%), and UTI was the most common infection (50%), causing readmission in the first 90 days post-transplant. The readmission odd ratio was significantly higher in patients above 60 years old and in kidneys with KDPI ≥ 85, and in recipients with DGF.

CONCLUSION

Early hospital readmission (EHR) following a kidney transplant is a common complication. Identifying the causes not only helps the transplant centers to take further steps to prevent some incidents and help to improve the patients' morbidities and mortalities, but also it can reduce the unnecessary costs of readmissions.

Use of organs from increased infectious risk deceased donors in pediatric kidney transplantation

Living donors are the main source of transplanted kidneys for children and young people in many countries, but there still remains a significant need for deceased donor kidney transplantation. Given the waiting times associated with deceased donor kidney transplantation and the morbidity or mortality that can occur in those on the waiting list, it is essential that the utilization of kidneys from deceased donors is optimized. The use of organs from deceased donors at increased risk of transmitting human immunodeficiency virus, hepatitis B virus, or hepatitis C virus is relatively common in adults, but far less so in children. The risks and benefits of the use of kidneys from increased infectious risk donors (IIRD) are discussed. The variation of definitions of IIRD between countries is explored as is the need for pediatric nephrologists and transplant surgeons to have an understanding of the prevalence of viral diseases within the country in which they work. The role of screening tests such as nucleic acid tests is examined, along with the concept of residual risk. Finally, considerations in acquiring informed consent in the use of kidneys from IIRDs in children and young people are discussed.

Does anybody really know what (the kidney median waiting) time is?

The median waiting time (MWT) to deceased donor kidney transplant is of interest to patients, clinicians, and the media but remains elusive due to both methodological and philosophical challenges. We used Organ Procurement and Transplantation Network data from January 2003 to March 2022 to estimate MWTs using various methods and timescales, applied overall, by era, and by candidate demographics. After rising for a decade, the overall MWT fell to 5.19 years between 2015 and 2018 and declined again to 4.05 years (April 2021 to March 2022), based on the Kaplan-Meier method applied to period-prevalent cohorts. MWTs differed markedly by blood type, donor service area, and pediatric vs adult status, but to a lesser degree by race/ethnicity. Choice of methodology affected the magnitude of these differences. Instead of waiting years for an answer, reliable kidney MWT estimates can be obtained shortly after a policy is implemented using the period-prevalent Kaplan-Meier approach, a theoretical but useful construct for which we found no evidence of bias compared with using incident cohorts. We recommend this method be used complementary to the competing risks approach, under which MWT is often inestimable, to fill the present information void concerning the seemingly simple question of how long it takes to get a kidney transplant in the United States.

Hypothermic machine perfusion alleviates ischemia-reperfusion injury of intestinal transplantation in pigs

Background

Intestinal transplantation (IT) has become an important procedure for the treatment of irreversible intestinal failure. However, IT is extremely vulnerable to ischemia-reperfusion injury (IRI). Due to the limitations of static cold storage (SCS), hypothermic machine perfusion (HMP) is rapidly gaining popularity. In this study, the intestinal HMP system is established and HMP is compared with SCS.

Methods

An intestinal HMP system was built. Ten miniature pigs were randomly divided into the HMP and SCS groups, and their intestines were perfused using the HMP device and SCS, respectively, followed by orthotopic auto-transplantation. Analysis was done on the grafts between the two groups.

Results

Operation success rates of the surgery were 100% in both groups. The 7-day survival rate was 100% in the HMP group, which was significantly higher than that of the SCS group (20%, P< 0.05). The pathological results showed that fewer injuries of grafts were in the HMP group. Endotoxin (ET), IL-1, IL-6, IFN-γ and TNF-α levels in the HMP group were significantly lower than in the SCS group (P<0.05), whereas IL-10 levels were significantly higher (P<0.05).The intestinal expression levels of ZO-1 and Occludin were higher in the HMP group compared to the SCS group, whereas Toll-like receptor 4 (TLR4), nuclear factor kappa B (NFκB), and caspase-3 were lower.

Conclusions

In this study, we established a stable intestinal HMP system and demonstrated that HMP could significantly alleviate intestinal IRI and improve the outcome after IT.

Cost-Utility of Immunosuppressive Therapy Post-Renal Transplantation in Saudi Arabia: The Saudi Ministry of Health Perspective

OBJECTIVES

Chronic kidney disease is ranked fourth among the top 10 causes of death in Saudi Arabia. Renal transplantation has been recognized as the treatment of choice compared with long-term dialysis to maintain graft survival and prolong a patient's healthy living. Immunosuppressants (ISs) must be administered lifelong. The choice between IS therapies can be challenging because of the similarity in efficacy with some differences in adverse events profile. The objective of this study was to assess the cost-effectiveness of different IS regimens in Saudi Arabia.

METHODS

A 25-year Markov model was developed based on a previously published study from the Saudi Ministry of Health payer perspective. Efficacy parameters were driven from the literature, whereas cost data were estimated from the Ministry of Health database. A Monte Carlo simulation was conducted to test the base-case model results' robustness.

RESULTS

All comparators resulted in 6.2 quality-adjusted life-years (QALYs) except for Advagraf® treatment (5.5 QALYs). Generic tacrolimus plus mycophenolate mofetil (MMF) will cost 70 701.45 US dollars ($) (Saudi riyal 265 130.44) per patient to gain 6.2 QALYs over 25 years' time horizon. In the improved adherence scenario, Envarsus® plus generic MMF generated 9.6 QALYs with a cost of $59 849 per patient. Monte Carlo simulation results have shown that generic tacrolimus is still the cheapest treatment option compared with other treatment arms.

CONCLUSIONS

The current analysis suggested that all IS options are not cost-effective strategies relative to the willingness-to-pay threshold of $20 000. Nevertheless, Envarsus plus generic MMF regimen could become the most cost-effective regimen at different willingness-to-pay thresholds.

Uncontrolled donation after cardiac death kidney transplantation: Opportunity to expand the donor pool?

BACKGROUND

Compared to controlled donation after cardiac death (cDCD), uncontrolled DCD (uDCD) kidney transplantation remains an underutilized resource in the United States. However, it is unclear whether long-term allograft outcomes following uDCD are inferior to that of cDCD kidney transplantation.

METHODS

From January 1995 to January 2018, the OPTN/UNOS database was queried to discover all reported cases of uDCD and cDCD kidney transplantation. Primary non-function, delayed graft function, ten-year graft and patient survival were compared among uDCD and cDCD patients.

RESULTS

Rates of primary non-function (4.0% [uDCD] vs. 1.8% [cDCD], P < 0.001) and delayed graft function (51.1% [uDCD] vs. 41.7% [cDCD], P < 0.001) were higher following uDCD transplant. However, ten-year graft survival (47.5% [uDCD] vs. 48.4% [cDCD], P = 0.21) and patient survival were similar to cDCD transplantation (59.4% [uDCD] vs. 59.2% [cDCD], P = 0.32).

CONCLUSION

Although initial allograft outcomes are inferior following uDCD, long-term durability of uDCD kidney allografts is on par to cDCD transplantation. Kidney allografts derived by uDCD may be a viable and durable option to increase the donor pool.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Rationale for the IMAGINE study for chronic active antibody-mediated rejection (caAMR) in kidney transplantation

Chronic active antibody-mediated rejection (caAMR) in kidney transplantation is a major cause of late graft loss and despite all efforts to date, there is no proven effective therapy. Indeed, the Transplant Society (TTS) consensus opinion called for a conservative approach optimizing baseline immunosuppression and supportive care focused on blood pressure, blood glucose, and lipid control. This review provides the rationale and early evidence in kidney transplant recipients with caAMR that supported the design of the IMAGINE study whose goal is to evaluate the potential impact of targeting the IL6/IL6R pathway.

Targeting inflammatory monocytes by immune-modifying nanoparticles prevents acute kidney allograft rejection

Inflammatory monocytes are a major component of the cellular infiltrate in acutely rejecting human kidney allografts. Since immune-modifying nanoparticles (IMPs) bind to circulating inflammatory monocytes via the specific scavenger receptor MARCO, causing diversion to the spleen and subsequent apoptosis, we investigated the therapeutic potential of negatively charged, 500-nm diameter polystyrene IMPs to prevent kidney allograft rejection. Kidney transplants were performed from BALB/c (H2^d) to C57BL/6 (H2^b) mice in two groups: controls (allo) and allo mice infused with IMPs. Groups were studied for 14 (acute rejection) or 100 (chronic rejection) days. Allo mice receiving IMPs exhibited superior survival and markedly less acute rejection, with better kidney function, less tubulitis, and diminished inflammatory cell density, cytokine and cytotoxic molecule expression in the allograft and lower titers of donor-specific IgG2c antibody in serum at day 14, as compared to allo mice. Cells isolated from kidneys from allo mice receiving IMPs showed reduced Ly6C^hi monocytes, CD11b⁺ cells and NKT⁺ cells compared to allo mice. IMPs predominantly bound CD11b⁺ cells in the bloodstream and CD11b⁺ and CD11c-B220⁺ marginal zone B cells in the spleen. In the spleen, IMPs were found predominantly in red pulp, colocalized with MARCO and expression of cleaved caspase-3. At day 100, allo mice receiving IMPs exhibited reduced macrophage M1 responses but were not protected from chronic rejection. IMPs afforded significant protection from acute rejection, inhibiting both innate and adaptive alloimmunity. Thus, our current experimental findings, coupled with our earlier demonstration of IMP-induced protection in kidney ischemia-reperfusion injury, identify IMPs as a potential induction agent in kidney transplantation.

Transplant Onconephrology: An Update

Transplant onconephrology is a growing specialty focused on the health care of kidney transplant recipients with cancer. Given the complexities associated with the care of transplant patients, along with the advent of novel cancer therapies such as immune checkpoint inhibitors and chimeric antigen-receptor T cells, there is a dire need for the subspecialty of transplant onconephrology. The management of cancer in the setting of kidney transplantation is best accomplished by a multidisciplinary team, including transplant nephrologists, oncologists, and patients. This review addresses the current state and future opportunities for transplant onconephrology, including the roles of the multidisciplinary team, and related scientific and clinical knowledge.

Tacrolimus Monotherapy is Safe in Immunologically Low-Risk Kidney Transplant Recipients: A Randomized-Controlled Pilot Study

In this randomized-controlled pilot study, the feasibility and safety of tacrolimus monotherapy in immunologically low-risk kidney transplant recipients was evaluated [NTR4824, www.trialregister.nl]. Low immunological risk was defined as maximal 3 HLA mismatches and the absence of panel reactive antibodies. Six months after transplantation, recipients were randomized if eGFR >30 ml/min, proteinuria <50 mg protein/mmol creatinine, no biopsy-proven rejection after 3 months, and no lymphocyte depleting therapy given. Recipients were randomized to tacrolimus/mycophenolate mofetil (TAC/MMF) or to taper and discontinue MMF at month 9 (TACmono). 79 of the 121 recipients were randomized to either TACmono (n = 38) or TAC/MMF (n = 41). Mean recipient age was 59 years and 59% received a living donor transplant. The median follow-up was 62 months. After randomization, 3 TACmono and 4 TAC/MMF recipients experienced a biopsy-proven rejection. At 5 years follow-up, patient survival was 84% in TACmono versus 76% in TAC/MMF with death-censored graft survival of 97% for both groups and no differences in eGFR and proteinuria. Eleven TACmono recipients had an infectious episode versus 22 TAC/MMF recipients (p < 0.03). Donor-specific anti-HLA antibodies were not detected during follow-up in both groups. Tacrolimus monotherapy in selected immunologically low-risk kidney transplant recipients appears safe and reduces the number of infections.

Outcomes of renal transplantation in patients with AL amyloidosis: an international collaboration through The International Kidney and Monoclonal Gammopathy Research Group

Effective systemic therapies suppress toxic light chain production leading to an increased proportion of patients with light chain (AL) amyloidosis who survive longer albeit with end-stage renal disease. There is a critical need to identify patients in this population who benefit from renal transplantation. This multicenter, observational study from five countries includes 237 patients with AL amyloidosis who underwent renal transplantation between 1987 and 2020. With a median follow-up of 8.5 years, the median overall survival from renal transplantation was 8.6 years and was significantly longer in patients with complete and very good partial hematologic responses (CR + VGPR) compared to less than VGPR (9 versus 6.8 years; HR: 1.5, P = 0.04 [95% CI: 1-2.1]) at renal transplantation. Median graft survival was 7.8 years and was better in the CR + VGPR group (8.3 vs 5.7 years, HR: 1.4, P = 0.05 [95% CI: 1-2]). The frequency and time to amyloid recurrence in the graft was also lower (16% vs 37%, p = 0.01) and longer (median time not achieved vs 10 years, p = 0.001) in the CR + VGPR group. Comparing CR vs. VGPR there was no difference in overall or graft survival. Although 69 patients (29%) experienced hematologic relapse, treatment effectively prevented graft loss in the majority (87%). Renal transplantation in selected AL amyloidosis patients is associated with extended overall and renal graft survival. Patients with hematologic CR or VGPR have the most favorable outcomes, and these patients should be considered for renal transplantation.

Clinical Implementation of Different Strategies for Exercise-Based Rehabilitation in Kidney and Liver Transplant Recipients: A Pilot Study

Fundamento:

A doença cardiovascular está entre as principais causas de morte entre pacientes transplantados. Embora esses pacientes possam teoricamente se beneficiar de programas de reabilitação baseada em exercícios (RBE), sua implementação ainda é um desafio.

Objetivo:

Apresentamos nossa experiência inicial em diferentes modos de realização de um programa piloto de RBE em receptores de transplante de rim e fígado.

Métodos:

Trinta e dois pacientes transplantados renais ou hepáticos foram convidados para um programa de RBE de 6 meses realizado na academia do hospital, na academia comunitária ou em casa, de acordo com a preferência do paciente. O nível de significância adotado foi de 5%.

Resultados:

Dez pacientes (31%) não completaram o programa. Entre os 22 que completaram, 7 treinaram na academia do hospital, 7 na academia comunitária e 8 em casa. O efeito geral foi um aumento de 11,4% nos METs máximos (tamanho do efeito de Hedges g = 0,39). O grupo de academia hospitalar teve um aumento nos METs de 25,5% (g = 0,58, tamanho de efeito médio) versus 10% (g = 0,25) e 6,5% (g = 0,20) para os grupos de academia comunitária e em casa, respectivamente. Houve efeito benéfico nas pressões arteriais sistólica e diastólica, maior para os grupos academia hospitalar (g= 0,51 e 0,40) e academia comunitária (g= 0,60 e 1,15) do que para os pacientes treinando em casa (g= 0,07 e 0,10). Nenhum evento adverso significativo foi relatado durante o seguimento.

Conclusão:

Programas de RBE em receptores de transplante de rim e fígado devem ser incentivados, mesmo que sejam realizados fora da academia do hospital, pois são seguros com efeitos positivos na capacidade de exercício e nos fatores de risco cardiovascular.

Antithymocyte globulin versus basiliximab induction for kidney transplantation in elderly patients: matched analysis within the Korean multicentric registry

Background

Basiliximab (BSX) and antithymocyte globulins (ATGs), are two major immunosuppressive agents commonly used as induction therapy for kidney transplant (KT) recipients. The superiority of ATG over BSX has not been well established, especially in elderly KT recipients with low immunological risk.

Methods

A total of 847 elderly (≥60 years old), low-risk KT patients in the Korean Organ Transplantation Registry were propensity score-matched at a 1:2 ratio and compared according to ATG or BSX induction therapy. The primary outcome was patient and graft survival and biopsy-proven acute cellular rejection. The secondary outcome was graft function, BK virus nephropathy, infection, cancer, new-onset diabetes mellitus after transplantation (NODAT), and delayed graft function.

Results

In total, 165 patients in the ATG group were matched with 298 patients in the BSX group with average ages of 64.3 and 64.2 years, respectively. During a follow-up of 28.5 ± 10.4 months, the cumulative probabilities of death-censored graft failure at 3 years posttransplantation were 1.3% and 1.4% in ATG and BSX groups, respectively, without a significant difference (p = 0.72). The cumulative probability of NODAT at 3 years posttransplantation was significantly higher in the BSX group (35.6% vs. 21.6%, p = 0.02). The median tacrolimus trough level was significantly lower at 6 months after KT in the ATG group (5.7 ng/mL vs. 6.4 ng/mL, p = 0.001). There were no differences in the other evaluated outcomes.

Conclusion

Compared with BSX, in elderly, low-risk KT patients, ATG reduced tacrolimus and steroid requirements without differences in all-cause mortality, rejection, or infection, resulting in a reduced NODAT incidence.

Impact of medical eligibility criteria and OPTN policy on simultaneous liver kidney allocation and utilization

BACKGROUND

Organ Procurement and Transplantation Network (OPTN) implemented medical eligibility and safety-net policy on 8/10/17 to optimize simultaneous liver-kidney (SLK) utilization. We examined impact of this policy on SLK listings and number of kidneys used within 1-yr. of receiving liver transplantation (LT) alone.

METHODS AND RESULTS

OPTN database (08/10/14-06/12/20) on adults (N = 66 709) without previous transplant stratified candidates to listings for SLK or LT alone with pre-LT renal dysfunction at listing (eGFR < 30 mL/min or on dialysis). Outcomes were compared for pre (08/10/14-08/09/17) vs. post (08/10/17-06/12/20) policy era. SLK listings decreased in post vs. pre policy era (8.7% vs. 9.6%; P < .001), with 22% reduced odds of SLK listing in the postpolicy era, with a decrease in all OPTN regions except regions 6 and 8, which showed an increase. Among LT-alone recipients with pre-LT renal dysfunction (N = 3272), cumulative 1-year probability was higher in post vs. prepolicy period for dialysis (5.6% vs. 2.3%; P < .0001), KT listing (11.4% vs. 2.0%; P < .0001), and KT (3.7% vs. .25%; P < .0001). Sixty-seven (2.4%) kidneys were saved in post policy era, with 18.1%, 16.6%, 4.3%, and 2.9% saving from regions 7, 2, 11, and 1, respectively.

CONCLUSION

Medical eligibility and safety-net OPTN policy resulted in decreased SLK use and improved access to LT alone among those with pre-LT renal dysfunction. Although decreased in postpolicy era, regional variation of SLK listings remains. In spite of increased use of KT within 1-year of receiving LT alone under safety net, less number of kidneys were used without impact on patient survival in postpolicy era.

Immunotherapy and Antivascular Targeted Therapy in Patients’ Treatment with Concurrent Malignant Tumors after Organ Transplantation: Opportunity or Challenge

Objective

To analyze the therapeutic effects and organ rejection of anti-PD-1 immunotherapy or antivascular targeting therapy on patients with combined malignancies after organ transplantation.

Methods

We collected retrospective studies on “post-transplantation, cancer, immunotherapy, and vascular targeting therapy” in Embase, Wanfang database, Cochrane Library, VIP databases, CNKI, and PubMed, and the case data were organized and analyzed.

Results

Data from only 40 papers met our requirements, which included 2 literature reviews, 4 original researches, and 34 case reports from 2016 to 2020. A total of 40 studies involving 66 patients were included, who were divided into 3 groups (patients using CTLA-4 inhibitors, group 1; patients who received sequential or concurrent anti-PD-1 and anti-CTLA-4 therapy, group 2; and patients using PD-1/PD-L1 inhibitors, group 3). There was no statistical difference in patients' DCR between the three groups (P > 0.05). Also, compared with group 2, there was no statistically significant difference in recipient organ rejection in group 1 and group 3 (P > 0.05). The DCR rate for antivascular targeted therapy is approximately 60%.

Conclusions

Immunotherapy should be carefully selected for patients with combined malignancies after organ transplantation. Antivascular targeted therapy is one of the options worth considering; the risk of side effects of drug therapy is something that needs to be closely monitored when combined with immunotherapy.