2202 kidney transplant recipients with 10 years of graft function: what happens next?

Endovascular Treatment for Transplant Renal Artery Stenosis: 10 Years' Experience from a Single Center

INTRODUCTION

Transplant renal artery stenosis (TRAS) is a common post-renal transplant complication. Although endovascular treatment is widely used to treat TRAS, previous research has been limited by small sample sizes. This article aimed to present the clinical outcomes of endovascular treatment for TRAS in a large sample.

METHODS

Between January 2010 and December 2019, this study included patients with TRAS who were admitted to our center. All patients' clinical symptoms, comorbidities, imaging data, treatment, and follow-up results were reviewed retrospectively.

RESULTS

Seventy two patients participated in this study. The median time between renal transplantation and TRAS was 5.25 months. Out of 72 patients, 55 (76.4%) received balloon dilatation in conjunction with stent deployment, 10 (13.9%) received drug-coated balloon dilatation alone, and 7 (9.7%) received balloon dilatation alone. The median follow-up period was 27 months. Primary patency rates were 100%, 81.8%, 74.5%, 64.6%, and 61.8% at 1, 3, 6, 12, and 24 months. A total of 23 patients were found to have restenosis during follow-up, with 6 (26.1%) requiring reintervention and none remaining restenosis after the second treatment. In the subgroup analysis of the three types of stenosis, patients with transplant renal stenosis at the anastomosis had a significantly higher rate of primary patency. Between endovascular treatments, the primary patency rate, postoperative creatinine clearance, and mean systolic blood pressure did not differ significantly.

CONCLUSION

Endovascular treatment resulted in favorable short-term patency as well as effective relief of renal dysfunction and renal hypertension in TRAS patients.

Targeted delivery of galunisertib using machine perfusion reduces fibrogenesis in an integrated ex vivo renal transplant and fibrogenesis model

BACKGROUND AND PURPOSE

Fibrosis in kidney allografts is a major post-transplant complication that contributes to graft failure. Lately, multiple potent inhibitors of fibrosis-related pathways have been developed such as galunisertib, an inhibitor of the transforming growth factor-beta (TGF-β/TGFβ1) signalling pathway. This drug, however, poses risks for adverse effects when administered systemically. Therefore, we devised a new repurposing strategy in which galunisertib is administered ex vivo. We combined machine perfusion and tissue slices to explore the antifibrotic effects of galunisertib in renal grafts.

EXPERIMENTAL APPROACH

Porcine kidneys were subjected to 30 min of warm ischaemia, 24 h of oxygenated hypothermic machine perfusion and 6 h of normothermic machine perfusion with various treatments (i.e. untreated control, TGFβ1, galunisertib or TGFβ1 + galunisertib; n = 8 kidneys per group). To determine whether effects persisted upon ceasing treatment, kidney slices were prepared from respective kidneys and incubated for 48 h.

KEY RESULTS

Galunisertib treatment improved general viability without negatively affecting renal function or elevating levels of injury markers or by-products of oxidative stress during perfusion. Galunisertib also reduced inflammation and, more importantly, reduced the onset of fibrosis after 48 h of incubation.

CONCLUSIONS AND IMPLICATIONS

Our findings demonstrate the value of using machine perfusion for administering antifibrotic drugs such as galunisertib, proving it to be an effective example of repurposing.

Long-term mortality in pediatric solid organ recipients-A nationwide study

BACKGROUND

The present study aimed at investigating long-term mortality of patients who underwent solid organ transplantation during childhood and at identifying their causes of death.

METHODS

A cohort of 233 pediatric solid organ transplant recipients who had a kidney, liver, or heart transplantation between 1982 and 2015 in Finland were studied. Year of birth-, sex-, and hometown-matched controls (n = 1157) were identified using the Population Register Center registry. The Causes of Death Registry was utilized to identify the causes of death.

RESULTS

Among the transplant recipients, there were 60 (25.8%) deaths (median follow-up 18.0 years, interquartile range of 11.0-23.0 years). Transplant recipients' risk of death was nearly 130-fold higher than that of the controls (95% CI 51.9-1784.6). The 20-year survival rates for kidney, liver, and heart recipients were 86.1% (95% CI 79.9%-92.3%), 58.5% (95% CI 46.2%-74.1%), and 61.4% (95% CI 48.1%-78.4%), respectively. The most common causes of death were cardiovascular diseases (23%), infections (22%), and malignancies (17%). There were no significant differences in survival based on sex or transplantation era.

CONCLUSION

The late mortality is still significantly higher among pediatric solid organ recipients in comparison with controls. Cardiovascular complications, infections, and cancers are the main causes of late mortality for all studied transplant groups. These findings emphasize the cruciality of careful monitoring of pediatric transplant recipients in order to reduce long-term mortality.

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.

Long-term outcomes and prognostic factors in kidney transplant recipients in Jakarta, Indonesia: a cohort study

OBJECTIVES

To determine the long-term survival rates and prognostic factors in kidney transplant (KT) recipients in Jakarta, Indonesia.

DESIGN

Retrospective cohort study.

SETTING

A KT centre in Jakarta.

PARTICIPANTS

We enrolled 754 consecutive adult recipients who underwent KT between 2010 and 2020.

MAIN OUTCOME MEASURES

Rates of 10-year patient, all-cause and death-censored graft survival and their prognostic factors in KT recipients.

RESULTS

The 10-year patient survival, all-cause survival and death-censored graft survival rates of KT recipients were 74%, 68% and 81%, respectively. The prognostic factors for poor patient survival were a pretransplant dialysis duration>24 months (HR 1.64, 95% CI, 1.08 to 2.49; p=0.02), cardiovascular disease (HR 1.59, 95% CI, 1.11 to 2.31; p=0.01), delayed graft function (DGF) (HR 4.94, 95% CI, 2.76 to 8.82; p<0.001), post-transplant infection (HR 2.63, 95% CI, 1.56 to 4.43; p<0.001) and acute rejection (HR 2.49, 95% CI, 1.20 to 5.15; p=0.01). All-cause graft survival was prognosticated by a pretransplant dialysis duration>24 months (HR 1.74, 95% CI, 1.15 to 2.47; p=0.007), cardiovascular disease (HR 1.65, 95% CI, 1.18 to 2.33; p=0.004), DGF (HR 5.39, 95% CI, 3.13 to 9.28; p<0.001), post-transplant infection (HR 2.46, 95% CI, 1.05 to 4.02; p<0.001) and acute rejection (HR 4.18, 95% CI, 2.23 to 7.84; p<0.001). Factors associated with poor death-censored graft survival were a pretransplant dialysis duration >24 months (HR 2.19, 95% CI, 1.32 to 3.63; p=0.002), cardiovascular disease (HR 1.65, 95% CI, 1.02 to 2.68; p=0.04) and acute rejection (HR 5.52, 95% CI, 2.80 to 10.83; p<0.001).

CONCLUSIONS

The survival rates of KT recipients are prognosticated by pretransplant dialysis duration, cardiovascular disease, DGF, post-transplant infection and acute rejection. Stricter eligibility criteria for recipients, more sensitive cross-match testing methods and better infection management strategies may be beneficial for improving the survival rates.

Exploring Porcine Precision-Cut Kidney Slices as a Model for Transplant-Related Ischemia-Reperfusion Injury

Marginal donor kidneys are more likely to develop ischemia-reperfusion injury (IRI), resulting in inferior long-term outcomes. Perfusion techniques are used to attenuate IRI and improve graft quality. However, machine perfusion is still in its infancy, and more research is required for optimal conditions and potential repairing therapies. Experimental machine perfusion using porcine kidneys is a great way to investigate transplant-related IRI, but these experiments are costly and time-consuming. Therefore, an intermediate model to study IRI would be of great value. We developed a precision-cut kidney slice (PCKS) model that resembles ischemia-reperfusion and provides opportunities for studying multiple interventions simultaneously. Porcine kidneys were procured from a local slaughterhouse, exposed to 30 min of warm ischemia, and cold preserved. Subsequently, PCKS were prepared and incubated under various conditions. Adenosine triphosphate (ATP) levels and histological tissue integrity were assessed for renal viability and injury. Slicing did not influence tissue viability, and PCKS remained viable up to 72 h incubation with significantly increased ATP levels. Hypothermic and normothermic incubation led to significantly higher ATP levels than baseline. William’s medium E supplemented with Ciprofloxacin (and Amphotericin-B) provided the most beneficial condition for incubation of porcine PCKS. The porcine PCKS model can be used for studying transplant IRI.

Doxycycline Alters the Porcine Renal Proteome and Degradome during Hypothermic Machine Perfusion

Ischemia-reperfusion injury (IRI) is a hallmark for tissue injury in donation after circulatory death (DCD) kidneys. The implementation of hypothermic machine perfusion (HMP) provides a platform for improved preservation of DCD kidneys. Doxycycline administration has shown protective effects during IRI. Therefore, we explored the impact of doxycycline on proteolytic degradation mechanisms and the urinary proteome of perfused kidney grafts. Porcine kidneys underwent 30 min of warm ischemia, 24 h of oxygenated HMP (control/doxycycline) and 240 min of ex vivo reperfusion. A proteomic analysis revealed distinctive clustering profiles between urine samples collected at T15 min and T240 min. High-efficiency undecanal-based N-termini (HUNTER) kidney tissue degradomics revealed significantly more proteolytic activity in the control group at T-10. At T240, significantly more proteolytic activity was observed in the doxycycline group, indicating that doxycycline alters protein degradation during HMP. In conclusion, doxycycline administration during HMP led to significant proteomic and proteolytic differences and protective effects by attenuating urinary NGAL levels. Ultimately, we unraveled metabolic, and complement and coagulation pathways that undergo alterations during machine perfusion and that could be targeted to attenuate IRI induced injury.

Shifting Paradigms for Suppressing Fibrosis in Kidney Transplants: Supplementing Perfusion Solutions With Anti-fibrotic Drugs

Great efforts have been made toward addressing the demand for donor kidneys. One of the most promising approaches is to use kidneys from donation after circulatory death donors. These kidneys, however, suffer from more severe ischemia and reperfusion injury than those obtained via donation after brain death and are thus more prone to develop interstitial fibrosis and tubular atrophy. Even though machine perfusion is increasingly used to reduce ischemia and reperfusion injury, there are no effective treatments available to ameliorate interstitial fibrosis and tubular atrophy, forcing patients to resume dialysis, undergo re-transplantation, or suffer from premature death. Safe and effective anti-fibrotic therapies are therefore greatly desired. We propose a new therapeutic approach in which machine perfusion solutions are supplemented with anti-fibrotic compounds. This allows the use of higher concentrations than those used in humans whilst eliminating side effects in other organs. To the authors' knowledge, no one has reviewed whether such an approach could reduce interstitial fibrosis and tubular atrophy; we therefore set out to explore its merit. In this review, we first provide background information on ischemia and reperfusion injury as well as interstitial fibrosis and tubular atrophy, after which we describe currently available approaches for preserving donor kidneys. We then present an evaluation of selected compounds. To identify promising compounds, we analyzed publications describing the effects of anti-fibrotic molecules in precision-cut kidneys slices, which are viable explants that can be cultured ex vivo for up to a few days whilst retaining functional and structural features. LY2109761, galunisertib, imatinib, nintedanib, and butaprost were shown to exert anti-fibrotic effects in slices within a relatively short timeframe (<48 h) and are therefore considered to be excellent candidates for follow-up ex vivo machine perfusion studies.

Equity or Equality? Which Approach Brings More Satisfaction in a Kidney-Exchange Chain?

In United States (U.S.), government-funded organizations, such as NLDAC, reimburse travel and subsistence expenses incurred during living-organ donation process. However, in Iran, there is a non-governmental organization called Iranian Kidney Foundation (IKF) that funds the direct and indirect costs of donors through charitable donations and contributions from participants in the exchange program. In this article, for countries outside the U.S. that currently use an equality approach, we propose a potential new compensation-apportionment approach (equitable approach) for kidney-exchange chains and compare it with the currently available system (equality approach) in terms of the apportionment of compensation in a kidney-exchange chain to cover the expenses incurred by the initiating living donor of the chain in the act of donation. To this end, we propose a mechanism to apportion compensation among all participating pairs based on the equity approach by utilizing a prediction model to calculate the probability of graft survival in each transplant operation. These probabilities are then used to define the utility of any transplantation, considering the quality of each pair’s donated and received kidney in the chain. Afterward, the corresponding cost is apportioned by a mechanism based on the normalized differences between the utility of donated and received kidneys for each incompatible pair of the chain. In summary, we demonstrate that by utilizing the equitable approach, there is more fairness and equity in the allocation of resources in organ-procurement systems, which results in more satisfaction among incompatible pairs. Additional future prospective studies are needed to assess this proposed equitable approach for kidney-exchange chains in countries outside the U.S., such as Iran, that currently use an equality approach.

Is It Time to Utilize Genetic Testing for Living Kidney Donor Evaluation?

Living donor kidney transplantation is an effective strategy to mitigate the challenges of solid organ shortage. However, being a living kidney donor is not without risk, as donors may encounter short- and long-term complications including the risk of developing chronic kidney disease, end-stage kidney disease, hypertension, and possible pregnancy-related complications. Although the evaluation of potential living donors is a thorough and meticulous process with the intention of decreasing the chance of complications, particularly in donors who have lifetime risk projection, risk factors for kidney disease including genetic predispositions may be missed because they are not routinely investigated. This type of testing may not be offered to patients due to variability and decreased penetrance of symptoms and lack of availability of appropriate genetic testing and genetic specialists. We report a case of a middle-aged woman with a history of gestational diabetes and preeclampsia who underwent an uneventful living kidney donation. She developed postdonation nonnephrotic range proteinuria and microscopic hematuria. Given the risk of biopsy with a solitary kidney, genetic testing was performed and revealed autosomal dominant Alport syndrome. Our case underscores the utility of genetic testing. Hopefully, future research will examine the incorporation of predonation genetic testing into living kidney donor evaluation.

Advanced Genomics-Based Approaches for Defining Allograft Rejection With Single Cell Resolution

Solid organ transplant recipients require long-term immunosuppression for prevention of rejection. Calcineurin inhibitor (CNI)-based immunosuppressive regimens have remained the primary means for immunosuppression for four decades now, yet little is known about their effects on graft resident and infiltrating immune cell populations. Similarly, the understanding of rejection biology under specific types of immunosuppression remains to be defined. Furthermore, development of innovative, rationally designed targeted therapeutics for mitigating or preventing rejection requires a fundamental understanding of the immunobiology that underlies the rejection process. The established use of microarray technologies in transplantation has provided great insight into gene transcripts associated with allograft rejection but does not characterize rejection on a single cell level. Therefore, the development of novel genomics tools, such as single cell sequencing techniques, combined with powerful bioinformatics approaches, has enabled characterization of immune processes at the single cell level. This can provide profound insights into the rejection process, including identification of resident and infiltrating cell transcriptomes, cell-cell interactions, and T cell receptor α/β repertoires. In this review, we discuss genomic analysis techniques, including microarray, bulk RNAseq (bulkSeq), single-cell RNAseq (scRNAseq), and spatial transcriptomic (ST) techniques, including considerations of their benefits and limitations. Further, other techniques, such as chromatin analysis via assay for transposase-accessible chromatin sequencing (ATACseq), bioinformatic regulatory network analyses, and protein-based approaches are also examined. Application of these tools will play a crucial role in redefining transplant rejection with single cell resolution and likely aid in the development of future immunomodulatory therapies in solid organ transplantation.

Advanced glycation end products and oxidative stress as a basis for metabolic abnormalities in patients with type 1 diabetes after successful simultaneous pancreas-kidney transplantation

Aim. To compare advanced glycation end-products (AGE, RAGE) and 3-nitrotyrosine (3-HT) in patients with DM 1 after successful simultaneous pancreas-kidney transplantation (SPK) and kidney transplantation alone (KTA). To assess relationship between levels of AGE, RAGE, 3-HT and renal transplant (RT) function, carbohydrate and mineral metabolism. Materials and methods. The study included 58 patients who received kidney transplantation in end-stage renal disease (ESRD). 36 patients received SPK. There were performed routine laboratory, examination of AGE, RAGE, 3-NT, parathyroid hormone (PTH), 25(OH)vitamin D, calcium, phosphorus, FGF23, osteoprotegerin (OPG), and fetuin-A levels. Results. All patients after SPK reached normoglycemia (HbA1c 5.7 [5.3; 6.1] %; C-peptide 3.24 [2.29; 4.40] ng/ml) with the achievement of significant difference vs patients after KTA. Arterial hypertension (AH) was more frequent in recipients of SPK before transplantation than after (p=0.008). AH also persisted in greater number of cases in patients after KTA than after SPK. Patients after SPK had higher AGE (р=0.0003) and lower RAGE (р=0.000003) levels. OPG in patients after SPK was significantly higher (р=0.04). The correlation analysis revealed significant positive correlation between 3-HT and OPG (p0.05; r=0.30), RAGE and eGFR (r=-0.52), HbA1c (r=0.48), duration of AH (r=0.34), AGE with HbA1c (r=0.51). Conclusion. The results of the "metabolic memory" markers analysis may indicate their contribution to the persistence of the metabolic consequences of CKD and DM 1 after achievement of normoglycemia and renal function restoration and their possible participation in development of recurrent nephropathy, vascular calcification, and bone disorders.

The Tacrolimus Metabolism Rate and Dyslipidemia after Kidney Transplantation

Fast tacrolimus (Tac) metabolism is associated with reduced survival rates after renal transplantation (RTx), mainly due to cardiovascular events. Because dyslipidemia is a leading cause of cardiovascular death, we hypothesized that most RTx patients do not achieve recommended target low-density lipoprotein cholesterol (LDL-C) levels (European cardiology society guidelines) and that fast Tac metabolizers have higher dyslipidemia rates. This study included RTx recipients who received initial immunosuppression with immediate-release tacrolimus (IR-Tac), mycophenolate, and prednisolone. Patients were grouped according to their Tac concentration-to-dose ratio (C/D ratio) 3 months after RTx. Dyslipidemia parameters were analyzed at RTx, 3 months, and 12 months after RTx. Statin use and renal function were documented in a 12-month follow-up, and death was documented in a 60-month follow-up. Ninety-six RTx recipients were divided into two groups: 31 fast Tac metabolizers (C/D ratio < 1.05 ng/mL·1/mg) and 65 slow metabolizers (C/D ratio ≥ 1.05 ng/mL·1/mg). There were no differences in triglyceride or cholesterol levels between groups at RTx, 3, and 12 months after RTx. A total of 93.5% of fast and 95.4% of slow metabolizers did not achieve target LDL-C levels (p = 0.657). Fast metabolizers developed lower renal function compared to slow metabolizers 12 months after RTx (p = 0.009). Fast metabolizers showed a 60 month survival rate of 96.8% compared to 94.7% in the slow metabolizer group (p = 0.811). As most RTx recipients do not reach recommended target LDL-C levels, individualized nutritional counseling and lipid-lowering therapy must be intensified. Fast Tac metabolism is associated with lower renal function after RTx, but does not play a significant role in dyslipidemia.

Urinary Carnosinase-1 Excretion is Associated with Urinary Carnosine Depletion and Risk of Graft Failure in Kidney Transplant Recipients: Results of the TransplantLines Cohort Study

Carnosine affords protection against oxidative and carbonyl stress, yet high concentrations of the carnosinase-1 enzyme may limit this. We recently reported that high urinary carnosinase-1 is associated with kidney function decline and albuminuria in patients with chronic kidney disease. We prospectively investigated whether urinary carnosinase-1 is associated with a high risk for development of late graft failure in kidney transplant recipients (KTRs). Carnosine and carnosinase-1 were measured in 24 h urine in a longitudinal cohort of 703 stable KTRs and 257 healthy controls. Cox regression was used to analyze the prospective data. Urinary carnosine excretions were significantly decreased in KTRs (26.5 [IQR 21.4–33.3] µmol/24 h versus 34.8 [IQR 25.6–46.8] µmol/24 h; p < 0.001). In KTRs, high urinary carnosinase-1 concentrations were associated with increased risk of undetectable urinary carnosine (OR 1.24, 95%CI [1.06–1.45]; p = 0.007). During median follow-up for 5.3 [4.5–6.0] years, 84 (12%) KTRs developed graft failure. In Cox regression analyses, high urinary carnosinase-1 excretions were associated with increased risk of graft failure (HR 1.73, 95%CI [1.44–2.08]; p < 0.001) independent of potential confounders. Since urinary carnosine is depleted and urinary carnosinase-1 imparts a higher risk for graft failure in KTRs, future studies determining the potential of carnosine supplementation in these patients are warranted.

Metabolic Consequences of Solid Organ Transplantation

Metabolic complications affect over 50% of solid organ transplant recipients. These include posttransplant diabetes, nonalcoholic fatty liver disease, dyslipidemia, and obesity. Preexisting metabolic disease is further exacerbated with immunosuppression and posttransplant weight gain. Patients transition from a state of cachexia induced by end-organ disease to a pro-anabolic state after transplant due to weight gain, sedentary lifestyle, and suboptimal dietary habits in the setting of immunosuppression. Specific immunosuppressants have different metabolic effects, although all the foundation/maintenance immunosuppressants (calcineurin inhibitors, mTOR inhibitors) increase the risk of metabolic disease. In this comprehensive review, we summarize the emerging knowledge of the molecular pathogenesis of these different metabolic complications, and the potential genetic contribution (recipient +/- donor) to these conditions. These metabolic complications impact both graft and patient survival, particularly increasing the risk of cardiovascular and cancer-associated mortality. The current evidence for prevention and therapeutic management of posttransplant metabolic conditions is provided while highlighting gaps for future avenues in translational research.

Comparison of two strategies based on mammalian target of rapamycin inhibitors in secondary prevention of non-melanoma skin cancer after kidney transplantation, a pilot study

After kidney transplantation, withdrawal of calcineurin inhibitors (CNI) and conversion to sirolimus (SRL) may reduce the occurrence of new non-melanoma skin cancer (NMSC). Conversely, a reduced CNI exposure with everolimus (EVR) is an alternative strategy that has not been thoroughly evaluated. We retrospectively compared the occurrence of newly diagnosed NMSCs in two cohorts of kidney transplant recipients (KTR) with at least one NMSC: 35 patients were converted to EVR with reduced CNI exposure (CNI/EVR group), whereas 46 patients were converted to SRL in association with mycophenolic acid (MPA) (SRL/MPA group). Two years after conversion, survival free of new NMSC was similar between the two cohorts (p = .37), with 19 KTR (54.3%) in the CNI/EVR group and 22 (47.8%) in the SRL/MPA group being diagnosed of at least one new NMSC. Half of the KTR from both groups showed adverse events, leading to mTORi discontinuation for 37.1% of KTR in the CNI/EVR group and 21.7% in the SRL/MPA group (p = .09). The incidence of rejections was similar between the two groups. In a retrospective cohort of KTR with at least one post-transplant NMSC, the outcome of the patients converted to a CNI/EVR regimen was not different from those converted to a SRL/MPA regimen.

Antihypertensive Treatment in Kidney Transplant Recipients-A Current Single Center Experience

Arterial hypertension affects the survival of the kidney graft and the cardiovascular morbidity and mortality of the recipient after kidney transplantation (KTx). Thus, antihypertensive treatment is necessary for a vast majority of these patients. Long-term data on antihypertensive drugs and their effects on allograft function after KTx is still limited, and further investigation is required. We retrospectively analyzed a cohort of 854 recipients who received a kidney transplant at our transplant center between 2007 and 2015 with regard to antihypertensive treatment and its influence on graft function and survival. 1-y after KTx, 95.3% patients were treated with antihypertensive therapy. Of these, 38.6% received mono- or dual-drug therapy, 38.0% received three to four drugs and 8.1% were on a regimen of ≥5 drugs. Beta-blockers were the most frequently used antihypertensive agents (68.1%). Neither the use of angiotensin-converting enzyme inhibitor/angiotensin receptor blockers (51.9%) and calcium channel blockers (51.5%), nor the use the use of loop diuretics (38.7%) affected allograft survival. Arterial hypertension and the number of antihypertensive agents were associated with unfavorable allograft outcomes (each p < 0.001). In addition to the well-known risk factors of cold ischemic time and acute rejection episodes, the number of antihypertensive drugs after one year, which reflects the severity of hypertension, is a strong predictor of unfavorable allograft survival.

Continuous function of 80 primary renal allografts for 30-47 years with maintenance prednisone and azathioprine/mycophenolate mofetil therapy: A clinical mosaic of long-term successes

Eighty primary renal allograft recipients, 61 living-related and 19 deceased donor, transplanted from 1963 through 1984 had continuous graft function for 30-47 years. They were treated with three different early immunosuppression programs (1963-1970: thymectomy, splenectomy, high oral prednisone; 1971-1979: divided-dose intravenous methylprednisolone; and 1980-1984: antilymphocyte globulin) each with maintenance prednisone and azathioprine, and no calcineurin inhibitor. Long-term treatment often included the anti-platelet medication, dipyridamole. Although both recipient and donor ages were young (27.2 ± 9.5 and 33.1 ± 12.0 years, respectively), six recipients with a parent donor had >40-year success. At 35 years, death-censored graft survival was 85.3% and death with a functioning graft 84.2%; overall graft survival was 69.5% (Kaplan-Meier estimate). Biopsy-documented early acute cellular and highly probable antibody-mediated rejections were reversed with divided-dose intravenous methylprednisolone. Complications are detailed in an integrated timeline. Hypogammaglobulinemia identified after 20 years doubled the infection rate. An association between a monoclonal gammopathy of undetermined significance and non-plasma-cell malignancies was identified. Twenty-seven azathioprine-treated patients tested after 37 years had extremely low levels of T1/T2 B lymphocytes representing a "low immunosuppression state of allograft acceptance (LISAA)". The lifetime achievements of these patients following a single renal allograft and low-dose maintenance immunosuppression are remarkable. Their success evolved as a clinical mosaic.

Risk of Graft Failure in Kidney Recipients with Cured Post-Transplant Cancer

BACKGROUND

Post-transplant cancer (PTC) is a critical complication after kidney transplantation. However, whether successfully cured PTC affects the long-term graft outcome remains unclear.

METHODS

We retrospectively reviewed 1,629 kidney transplant recipients from 1995 to 2017 after excluding patients with post-transplant hematologic or advanced non-curable cancers and who underwent allograft nephrectomy because of cancer. Cured PTCs were defined as cancers treated with curative methods and/or adjuvant therapy without recurrence during ≥ 2 years. Propensity score matching was performed to match cured PTC patients with cancer-naïve patients (i.e., non-PTC group).

RESULTS

During the median period of 7 years (maximum, 23 years), 70 patients (4.3%) had cured PTCs. The PTC group showed significantly higher risks of death-censored graft failure (adjusted hazard ratio [HR], 2.56 [1.05-6.23]), class II donor-specific antibodies (adjusted HRs, 3.37 [1.30-8.71]), estimated glomerular filtration rate < 30 mL/min/1.73 m² (adjusted HR, 2.68 [1.43-5.02]) and random urine protein/creatinine ratio > 1 g (adjusted HR, 3.61 [1.92-6.79]) compared to non-PTC group. However, the risk of mortality was not different between the PTC and non-PTC groups. According to the cancer type, only urogenital cancer had a significant association with graft failure (adjusted HR, 4.26 [1.19-15.22]) and the gastrointestinal cancer showed elevated risk of T cell mediated rejection compared to non-PTC (adjusted HR, 20.44 [6.02-69.39]).

CONCLUSION

Appropriate monitoring of graft function is necessary in patients with cured PTCs.

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.

Change in the Pattern of Posttransplantation Anemia in Kidney Receptors: Sex Role in Recipients and Type of Donor

OBJECTIVE

Posttransplant anemia (PTA) in kidney recipients is a complication that has repercussions mainly of cardiovascular consequence. The objective of this study is to determine the prevalence of anemia, as well as the relationship between kidney recipient and donor sex, in the presence or absence of anemia at 12 months after kidney transplant (KT).

MATERIAL AND METHODS

Observational, longitudinal study of KTs made over a 5-year period, from 2013 to 2017, in a renal transplant unit from La Raza National Health Care Medical Center. Three hundred twenty-eight records were analyzed. Hemoglobin (Hb) and the presence or absence of anemia according to the definition by the World Health Organization were analyzed. The association between kidney recipient sex and donor type (living or deceased) was evaluated. Analysis of central tendency and dispersion were performed and the mean difference was established with χ² test or Student t test. Significance level was set at P < .05.

RESULTS

The mean Hb (standard deviation) before KT was 10.38 (2.16) g/dL; Hb at 12 months was 14.47 (2.37) g/dL with an absolute increase of 4.09 g/dL. Before KT, male kidney recipients had a mean Hb of 10.54 (2.17) g/dL. At 12 months post-KT, mean Hb was 15.33 (2.25) with a change of 4.79 g/dL. Before KT, female kidney recipients had a mean Hb of 10.16 (2.13) g/dL. At 12 months post-KT, mean Hb was 13.31 (2.01) with a change of 3.15 g/dL. The difference between both sexes was 1.64 g/dL at the end of 12 months. Sixteen out of 152 (10.5%) patients had a serum creatinine (Cr) < 1.2 mg/dL and anemia; 36 out of 176 (20.5%) patients had a Cr ≥ 1.2 mg/dL and anemia (P = .014). In the bivariate logistic regression with an odds ratio of 2.047 (95% confidence interval, 1027-4078; P = .042) for higher Cr levels and the presence of persistent anemia.

CONCLUSIONS

There is a prevalence of anemia in female kidney recipients and recipients of kidneys from deceased donors. There is a higher risk of persistent anemia in the case of patients with some degree of graft failure at 12 months.

Urinary sulfate excretion and risk of late graft failure in renal transplant recipients - a prospective cohort study

Hydrogen sulfide (H₂S), produced from metabolism of dietary sulfur‐containing amino acids, is allegedly a renoprotective compound. Twenty‐four‐hour urinary sulfate excretion (USE) may reflect H₂S bioavailability. We aimed to investigate the association of USE with graft failure in a large prospective cohort of renal transplant recipients (RTR). We included 704 stable RTR, recruited at least 1 year after transplantation. We applied log‐rank testing and Cox regression analyses to study association of USE, measured from baseline 24 h urine samples, with graft failure. Median age was 55 [45–63] years (57% male, eGFR was 45 ± 19 ml/min/1.73 m²). Median USE was 17.1 [13.1–21.1] mmol/24 h. Over median follow‐up of 5.3 [4.5–6.0] years, 84 RTR experienced graft failure. RTR in the lowest sex‐specific tertile of USE experienced a higher rate of graft failure during follow‐up than RTR in the middle and highest sex‐specific tertiles (18%, 13%, and 5%, respectively, log‐rank P < 0.001). In Cox regression analyses, USE was inversely associated with graft failure [HR per 10 mmol/24 h: 0.37 (0.24–0.55), P < 0.001]. The association remained independent of adjustment for potential confounders, including age, sex, eGFR, proteinuria, time between transplantation and baseline, BMI, smoking, and high sensitivity C‐reactive protein [HR per 10 mmol/24 h: 0.51 (0.31–0.82), P = 0.01]. In conclusion, this study demonstrates a significant inverse association of USE with graft failure in RTR, suggesting high H₂S bioavailability as a novel, potentially modifiable factor for prevention of graft failure in RTR.

A critical review of the relationship between post-transplant atherosclerotic events and cytomegalovirus exposure in kidney transplant recipients

Introduction: Cytomegalovirus (CMV) infection after kidney transplantation (KT) has been implicated in the so-called 'indirect effects' attributable to the viral ability to evade host's immunity and trigger sustained inflammation. Whether CMV exposure contributes to the development of post-transplant atherosclerotic events (AEs) remains controversial.Areas covered: This review (based on a PubMed/MEDLINE search from database inception to October 2019) summarizes the proposed mechanisms for the role of CMV in atherogenesis, including accelerated immunosenescence, endothelial injury and inflammatory milieu in the vessel wall. Sero-epidemiological evidence linking CMV exposure and cardiovascular disease in the general population is discussed. Finally, we performed a comprehensive review of observational studies investigating the impact of CMV infection on the occurrence of AE after KT, as well as the potential protective effect of antiviral prophylaxis.Expert opinion: Reviewed studies provide biological plausibility and preliminary clinical evidence pointing to the pathogenic role of CMV in post-transplant atherogenesis. However, no definitive recommendations can be made regarding the use of antiviral prophylaxis to prevent post-transplant AE, since existing evidence is mainly founded on inadequately powered post hoc analysis. Well-designed observational studies should clarify the differential impact of prophylactic or preemptive approaches on the occurrence of CMV-associated post-transplant AE among KT recipients.

Statin Safety and Associated Adverse Events: A Scientific Statement From the American Heart Association

One in 4 Americans >40 years of age takes a statin to reduce the risk of myocardial infarction, ischemic stroke, and other complications of atherosclerotic disease. The most effective statins produce a mean reduction in low-density lipoprotein cholesterol of 55% to 60% at the maximum dosage, and 6 of the 7 marketed statins are available in generic form, which makes them affordable for most patients. Primarily using data from randomized controlled trials, supplemented with observational data where necessary, this scientific statement provides a comprehensive review of statin safety and tolerability. The review covers the general patient population, as well as demographic subgroups, including the elderly, children, pregnant women, East Asians, and patients with specific conditions such as chronic disease of the kidney and liver, human immunodeficiency viral infection, and organ transplants. The risk of statin-induced serious muscle injury, including rhabdomyolysis, is <0.1%, and the risk of serious hepatotoxicity is ≈0.001%. The risk of statin-induced newly diagnosed diabetes mellitus is ≈0.2% per year of treatment, depending on the underlying risk of diabetes mellitus in the population studied. In patients with cerebrovascular disease, statins possibly increase the risk of hemorrhagic stroke; however, they clearly produce a greater reduction in the risk of atherothrombotic stroke and thus total stroke, as well as other cardiovascular events. There is no convincing evidence for a causal relationship between statins and cancer, cataracts, cognitive dysfunction, peripheral neuropathy, erectile dysfunction, or tendonitis. In US clinical practices, roughly 10% of patients stop taking a statin because of subjective complaints, most commonly muscle symptoms without raised creatine kinase. In contrast, in randomized clinical trials, the difference in the incidence of muscle symptoms without significantly raised creatinine kinase in statin-treated compared with placebo-treated participants is <1%, and it is even smaller (0.1%) for patients who discontinued treatment because of such muscle symptoms. This suggests that muscle symptoms are usually not caused by pharmacological effects of the statin. Restarting statin therapy in these patients can be challenging, but it is important, especially in patients at high risk of cardiovascular events, for whom prevention of these events is a priority. Overall, in patients for whom statin treatment is recommended by current guidelines, the benefits greatly outweigh the risks.

The impact of immunosuppression on postoperative graft function after graft-unrelated surgery: a retrospective controlled cohort study

Background

Physicians are faced with a growing number of patients after renal transplantation undergoing graft-unrelated surgery. So far, little is known about the postoperative restitution of graft function and the risk factors for a poor outcome.

Methods

One hundred one kidney transplant recipients undergoing graft-unrelated surgery between 2005 and 2015 were reviewed retrospectively. A risk analysis was performed and differences in creatinine, GFR and immunosuppressive treatment were evaluated. Additional, a comparison with a case-matched non-transplanted control group were performed.

Results

Preoperative creatinine averaged 1.88 mg / dl [0.62–5.22 mg / dl] and increased to 2.49 mg / dl [0.69–8.30 mg / dl] postoperatively. Acute kidney failure occurred in 18 patients and 14 patients had a permanent renal failure. Significant risk factors for the development of postoperative renal dysfunction were female gender, a preoperative creatinine above 2.0 mg / dl as well as a GFR below 40 ml / min and emergency surgery. Patients with tacrolimus and mycophenolate mofetil treatment showed a significant lower risk of renal dysfunction than patients with other immunosuppressants postoperatively. Contrary to that, the risk of patients with cyclosporine treatment was significantly increased. Transplanted patients showed a significantly increased rate of postoperative renal dysfunction.

Conclusions

The choice of immunosuppressant might have an impact on graft function and survival of kidney transplant recipients after graft-unrelated surgery. Further investigations are needed.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1358-2) contains supplementary material, which is available to authorized users.

Causes of late transplant failure in cyclosporine-treated kidney allograft recipients

BACKGROUND

There is little information about very long-term outcomes of kidney allograft recipients exposed to calcineurin inhibitors.

METHODS

In this single-centre retrospective study with 20-year follow-up, we analyzed data from 644 patients who underwent primary renal transplantation between 1983 and 1993. Participants were treated with a cyclosporine-based immunosuppressive scheme and had allograft function at 1 year.

RESULTS

After 20 years, 15.2% patients died, 39.7% experienced allograft loss, 26.8% were alive with a functioning transplant, and 18.2% were lost to follow-up. Cardiovascular disease (30.8%), malignancy (26.6%) and infection (17.0%) were the main causes of death. Age, new-onset proteinuria > 1 g/day, major acute cardiovascular event (MACE), and malignancy were independent predictors of mortality at time-dependent multivariate analysis. Chronic rejection (63.3%), recurrent glomerulonephritis (14.0%), and nonspecific interstitial fibrosis/tubular atrophy (13.2%) were the leading cause of allograft loss. Basal disease, hepatitis C, difference between 1 year and nadir serum creatinine, new-onset proteinuria > 1 g/day, and MACE were independent predictors of transplant failure. Among patients with 20-year allograft function, we recorded the following complications: hypertension (85%), malignancy (13%), diabetes (9%), and cardiovascular disease (9%). Median serum creatinine and proteinuria were 1.4 mg/dL and 0.6 g/day, respectively.

CONCLUSIONS

Prolonged use of cyclosporine may expose to several dose-related adverse events and may contribute to the development of allograft dysfunction but it does not necessarily cause relentless, progressive transplant failure if patients are carefully and consistently monitored during the follow-up.

Practice patterns in arteriovenous fistula ligation among kidney transplant recipients in the United States Renal Data Systems

BACKGROUND

Arteriovenous fistulas (AVF) and grafts (AVG) have been associated with significant cardiac morbidity that often improves after ligation. However, AV access ligation after kidney transplant (KT) is controversial due to concern for potential long-term allograft failure. We investigated US trends in AV access ligation after KT and the association between ligation and allograft failure.

METHODS

All adult Medicare patients on pretransplant hemodialysis with a functioning AVF or AVG who underwent first-time KT were studied using the United States Renal Data Systems (January 2011 to December 2013). Post-transplant AV access ligation was determined using current procedural terminology codes. The incidence of post-transplant AV access ligation was described, and characteristics for patients undergoing ligation vs no ligation were compared. Kaplan-Meier curves and Cox proportional hazard models were then used to determine the association of AV access ligation with long-term allograft failure and all-cause mortality after accounting for patient characteristics, donor characteristics, and variation in transplant center practices.

RESULTS

A total of 16,845 patients with functioning AVF/AVG received a KT during the study period. Of these, 779 (4.6%) underwent post-transplant AV access ligation. The proportion of patients who underwent ligation varied substantially between transplant centers, ranging from 0% (43.0% of centers) to >10% (11.0% of centers). Transplant recipients who underwent access ligation were more likely to be female (40.4% vs 36.6%), had lower median body mass index (27.6 vs 28.4 kg/m²), spent longer on dialysis pretransplant (4.2 vs 4.0 years), and were less likely to have renal failure secondary to diabetes compared with other etiologies (25.0% vs 34.9%) (all, P ≤ .03). Patients who underwent ligation were also more likely to have steal syndrome (77.2% vs 4.1%) and AV access infectious or aneurysmal complications (2.7% vs 0.7%) (both, P < .001). After adjusting for donor and recipient characteristics, increasing age (adjusted hazards ratio [aHR], 1.01; 95% confidence interval [CI], 1.00-1.01), increasing years on dialysis (aHR, 1.06; 95% CI, 1.00-1.13), zero human leukocyte antigen mismatch (aHR, 1.82; [95% CI, 1.09-3.05), and steal syndrome (aHR, 41.00; 95% CI, 34.56-48.64) were associated with post-transplant AV access ligation. Black race (aHR, 0.82; 95% CI, 0.69-0.98) and congestive heart failure (aHR, 0.66; 95% CI, 0.54-0.82) were negatively associated with ligation. Three-year allograft failure occurred in 4.9% ± 1.3% transplant recipients who underwent access ligation vs 9.5% ± 0.5% transplant recipients with functioning access (log-rank, P = .30), and was not significantly different between groups after risk adjustment (aHR, 0.81; 95% CI, 0.47-1.40). There was also no significant association between AV access and all-cause mortality after risk adjustment (aHR, 0.84; 95% CI, 0.46-1.54).

CONCLUSIONS

Post-transplant AV access ligation is uncommon and generally reserved for patients with steal syndrome. Importantly, ligation is not associated with post-transplant allograft failure, which occurs in less than 10% of patients at 3 years. There also appears to be no reduction in all-cause mortality with AV access ligation. These data suggest that AV access ligation after KT can likely be reserved for access-related complications because the systemic benefits appear to be minimal.

The Risk of Stroke in Kidney Transplant Recipients with End-Stage Kidney Disease

Background: The incidence of stroke after kidney transplantation is poorly understood. Our study aimed to determine the incidence and predictors of stroke as well as mortality from stroke in kidney transplant recipients (KTRs). Methods: This retrospective cohort study used the National Health Insurance Research Database in Taiwan to study KTRs (N = 4635), patients with end-stage renal disease (ESRD; N = 69,297), and patients from the general population who were chronic kidney disease (CKD)-free and matched by comorbidities (N = 69,297) for the years 2000 through 2010. The risk of stroke was analyzed using univariate and multivariate Cox regression models and compared between study cohorts. Findings: Compared with the ESRD subgroup, KTRs had a significantly lower risk of overall stroke (adjusted hazard ratio (aHR) = 0.37, 95% confidence interval (CI) = 0.31⁻0.44), ischemic stroke (aHR = 0.45, 95% CI = 0.37⁻0.55), and hemorrhagic stroke (aHR = 0.20, 95% CI = 0.14⁻0.29). The risk patterns for each type of stroke in the KTR group were not significantly different than those of the CKD-free control subgroup. The predictors of stroke were age and diabetes in KTRs. All forms of stroke after transplantation independently predicted an increased risk of subsequent mortality, and the strongest risk was related to hemorrhagic events. Interpretation: KTRs had a lower risk of stroke than ESRD patients, but this risk was not significantly different from that of the CKD-free comorbidities-matched general population group. Although stroke was relatively uncommon among cardiovascular events, it predicted unfavorable outcome in KTRs.

Characteristics and Outcomes of Kidney Transplant Recipients with a Functioning Graft for More than 25 Years

Background

Information regarding the clinical characteristics and outcomes of kidney transplant recipients (KTRs) with > 25 years of graft survival is limited.

Methods

In this single-center observational study, we characterized KTRs transplanted between 1973 and 1992 with active follow-up as of July 31, 2017.

Results

We identified 112 patients with > 25 years of allograft function. The mean posttransplantation follow-up was 29.8 ± 4.0 years. Glomerulonephritis was the most common cause of end-stage renal disease (ESRD) (52%). The majority received live donor transplants (66%), including 25 patients (22%) with human leukocyte antigen-matched kidneys. The incidence of biopsy-confirmed acute rejection was 21%, ranging from 0 to 26 years post transplantation. Donor-specific antibodies (DSA) were checked in 80% of patients at a mean of 28.4 ± 0.11 years post transplantation. Of these, only 15% were positive. The incidence of malignancy was 44%, with nonmelanoma skin cancers being most common. The incidence of infectious complications was 77%, mostly represented by urinary tract infections. At the time of last follow-up, 63% were on a calcineurin inhibitor (CNI)-free regimen, mean serum creatinine was 1.4 ± 0.6 mg/dL, and the prevalence of hypertension and dyslipidemia was 89 and 88%, respectively.

Conclusion

The majority of patients with a long-term functioning graft had glomerulonephritis as cause of ESRD, had received a live donor kidney, were on a CNI-free regimen, and had a low incidence of DSA and opportunistic infections. These characteristics define a unique group of patients requiring specific posttransplantation monitoring and management.

Long-term Graft and Patient Survival after Percutaneous Angioplasty or Arterial Stent Placement for Transplant Renal Artery Stenosis: A 21-year Matched Cohort Study

Purpose To compare long-term graft and patient survival after percutaneous angioplasty (PTA) or stent placement for transplant renal artery stenosis (TRAS) with a control cohort without TRAS. Materials and Methods This is a retrospective matched cohort study of 41 patients (median age, 49 years; range, 18-72 years), including 27 male patients (median age, 48 years; range, 18-67 years) and 14 female patients (median age, 52 years; range, 24-68 years), with TRAS from December 1995 through 2016. Primary end points were death-censored graft and patient survival, compared by using log-rank test and Cox proportional regression. Secondary outcomes were improvement in renal function, blood pressure (BP), and complications. Results Twenty-four patients underwent PTA and 17 received stent placements. Ten-year graft survival was 92.1% (range, 83.2%-100%) versus 81.4% (range, 67.8%-95.3%) (P = .56), and 10-year patient survival was 89.9% (79.1%-100%) versus 84.7% (72.1%-97.5%) (P = .49), for the study and control groups, respectively. Five patients (12%) resumed dialysis in each group and a total of 17 patients died (eight in the study group and nine in the control group). Most patients died with a functioning graft (seven of eight in the study group and seven of nine in the control group). Posttreatment median systolic and diastolic BP improved by 12% and 7.4%, respectively, and serum creatinine improved by 27%. Normal systolic BP and serum creatinine level at 1 year after treatment were associated with better survival for patients (P = .04; hazard ratio [HR], 1.04; 95% confidence interval [CI]: 1.0, 1.075) and grafts (P < .001; HR, 1.02; 95% CI: 1.0, 1.027). Other covariates, including PTA versus renal stent placement, intra-arterial pressure gradient greater than 10%, diastolic BP, age at transplantation, sex, graft type, rejection, and delayed graft function, were not significant. Five patients (12.2%) had a complication (Society of Interventional Radiology class A, two of 41 [4.9%]; class B, two of 41 [4.9%]; and class D, one of 41 [2.4%]); 30-day graft loss and patient mortality were zero. Conclusion Long-term graft and patient survival after endovascular correction of transplant renal artery stenosis (TRAS) was similar to that without TRAS and most patients avoided returning to dialysis. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Dickey and Durrani in this issue.

Inferior long-term allograft and patient outcomes among recipients of offspring living donor kidneys

While offspring-to-parent living donor kidney transplantations may represent an ideal donor-recipient combination to optimize long-term transplantation outcomes, the sex-specific long-term success of these transplantations remains unclear. We hypothesize that allograft and recipient survivals in offspring-to-parent living donor kidney transplantation differ between men and women due to donor-specific alloimmunization during pregnancy. We retrospectively analyzed long-term allograft and patient survival among men and women who received an offspring living donor kidney compared with those who received other haplotype-matched living donor kidneys. Based on multivariable Cox proportional hazards modeling of Organ Procurement and Transplantation Network data from 2001 to 2015, we found that both men and women who received offspring living donor kidneys had significantly increased mortality compared with recipients who received nonoffspring living donor kidneys. While male recipients of any living donor kidney had greater risk of mortality and allograft failure than female recipients, there was no significant difference in all-cause allograft failure or mortality in male versus female recipients of offspring living donor kidney transplantations. Our analysis demonstrated no significant interaction between recipient sex and donor offspring status. We conclude that nonoffspring living donors should be considered whenever feasible for both men and women with multiple donor options.

The Spectrum of Histopathological Changes in the Renal Allograft - a 12 Months Protocol Biopsy Study

INTRODUCTION

Renal transplantation became a routine and successful medical treatment for Chronic Kidney Disease in the last 30 years all over the world. Introduction of Luminex based Single Antigen Beads (SAB) and recent BANFF consensus of histopathological phenotypes of different forms of rejection enables more precise diagnosis and changes the therapeutic approach. The graft biopsies, protocol or cause, indicated, remain a golden diagnostic tool for clinical follow up of kidney transplant recipients (KTR).

AIM

The study aimed to analyse the histopathological changes in renal grafts 12 months after the surgery in KTR with satisfactory kidney function.

MATERIAL AND METHODS

A 12-month protocol biopsy study was performed in a cohort of 50 Kidney transplant recipients (42 from living and 8 from deceased donors). Usual work-up for suitable donors and recipients, standard surgical procedure, basic principles of peri and postoperative care and follow up were done in all KTR. Sequential quadruple immunosuppression including induction with Anti-thymocyte globulin (ATG) or Interleukin-2R antagonist (IL-2R), and triple drug maintenance therapy with Calcineurin Inhibitors (CNI), Mycophenolate Mofetil (MMF) and Steroids were prescribed to all pts. Different forms of Glomerulonephritis (16), Hypertension (10), End Stage Renal Disease (13), Hereditary Nephropathies (6), Diabetes (3) and Vesicoureteral Reflux (2) were the underlying diseases. All biopsies were performed under ultrasound guidance. The 16 gauge needles with automated "gun" were used to take 2 cores of tissue. The samples were stained with HE, PAS, Trichrome Masson and Silver and reviewed by the same pathologist. A revised and uploaded BANFF 2013 classification in 6 categories (Cat) was used.

RESULTS

Out of 48 biopsies, 15 (31%) were considered as normal, 4 (8%), Borderline (BL-Cat 3), 5 (10%) as Interstitial Fibrosis/Tubular Atrophy (IF/TA-Cat 5), 5 (10%) were classified as non-immunological (Cat 6), 2 as a pure antibody-mediated rejection (ABMR-Cat 2) and T-cell Mediated Rejection (TCMR-Cat 4). The remaining 17 samples were classified as a "mixed" rejection: 7 (41%) ABMR + IF/TA, 5 (29%) ABMR + BL + IF/TA, 2 (11%) BL + IF/TA, 1 (5%) ABMR + BL, 1 (5%) ABMR + TCMR and 1 (5%) TCMR + IF/TA. The mean serum creatinine at the time of the biopsy was 126.7 ± 23.4 µmol/L, while GFR-MDRD 63.4 ± 20.7 ml/min, which means that the majority of the findings were subclinical. Among the non-immunological histological findings (Cat 6), 3 cases belonged to CNI toxicity, 1 to BK nephropathy and 1 to recurrence of the primary disease.

CONCLUSION

Our 12-month protocol biopsy study revealed the presence of different forms of mixed subclinical rejection. Use of recent BANFF classification and scoring system enables more precise diagnosis and subsequently different approach to the further treatment of the KTR. More correlative long-term studies including Anti HLA antibodies and Endothelial Cell Activation- Associated Transcripts (ENDAT) are needed.

Kidney transplantation in Romania: two transplant centers experience

PURPOSE

Kidney graft survival rates improved from decade to decade, but data about factors that affect patient and graft survival remain challenging and even controversial.

METHODS

We analyzed retrospectively data from kidney transplanted patients followed in two Romanian transplant centers (Iasi and Bucharest)-new programmes specifically developed after 1989 to cover transplantation requirements for two-thirds of Romania. We used a composite survival outcome defined as 50% reduction in estimated glomerular filtration rate (eGFR), return to dialysis or death. Survival analysis was performed using uni- and multivariable Cox regression with baseline and time-updated covariates.

RESULTS

From the entire cohort of 365 patients, 243 had the outcome of interest. In the univariable Cox survival analysis, age, hemoglobin, eGFR, cholesterol, AST and transplant center were associated with the outcome. The multivariable Cox analysis reveals that only cholesterol (HR 0.97, 95% CI 0.94-0.99 per 10 mg/dL increase) and transplant center (HR 3.64, 95% CI 2.67-4.97) remain associated. For the time-updated Cox survival analysis we found that eGFR (HR 0.91, 95% CI 0.87-0.96 per 10 ml/min/1.73 m² increase) and cholesterol are associated with the outcome in the univariable analysis and only eGFR and transplant center in the multivariable Cox survival analysis.

CONCLUSIONS

Our study reports data from two distinct transplant centers from a developing country. Our results are similar to the current literature data, but also reveal that the approach of a center to the transplantation management is an independent factor associated with graft survival.

Toward Establishing Core Outcome Domains For Trials in Kidney Transplantation: Report of the Standardized Outcomes in Nephrology-Kidney Transplantation Consensus Workshops

BACKGROUND

Treatment decisions in kidney transplantation requires patients and clinicians to weigh the benefits and harms of a broad range of medical and surgical interventions, but the heterogeneity and lack of patient-relevant outcomes across trials in transplantation makes these trade-offs uncertain, thus, the need for a core outcome set that reflects stakeholder priorities.

METHODS

We convened 2 international Standardized Outcomes in Nephrology-Kidney Transplantation stakeholder consensus workshops in Boston (17 patients/caregivers; 52 health professionals) and Hong Kong (10 patients/caregivers; 45 health professionals). In facilitated breakout groups, participants discussed the development and implementation of core outcome domains for trials in kidney transplantation.

RESULTS

Seven themes were identified. Reinforcing the paramount importance of graft outcomes encompassed the prevailing dread of dialysis, distilling the meaning of graft function, and acknowledging the terrifying and ambiguous terminology of rejection. Reflecting critical trade-offs between graft health and medical comorbidities was fundamental. Contextualizing mortality explained discrepancies in the prioritization of death among stakeholders-inevitability of death (patients), preventing premature death (clinicians), and ensuring safety (regulators). Imperative to capture patient-reported outcomes was driven by making explicit patient priorities, fulfilling regulatory requirements, and addressing life participation. Specificity to transplant; feasibility and pragmatism (long-term impacts and responsiveness to interventions); and recognizing gradients of severity within outcome domains were raised as considerations.

CONCLUSIONS

Stakeholders support the inclusion of graft health, mortality, cardiovascular disease, infection, cancer, and patient-reported outcomes (ie, life participation) in a core outcomes set. Addressing ambiguous terminology and feasibility is needed in establishing these core outcome domains for trials in kidney transplantation.

Developing Consensus-Based Priority Outcome Domains for Trials in Kidney Transplantation: A Multinational Delphi Survey With Patients, Caregivers, and Health Professionals

BACKGROUND

Inconsistencies in outcome reporting and frequent omission of patient-centered outcomes can diminish the value of trials in treatment decision making. We identified critically important outcome domains in kidney transplantation based on the shared priorities of patients/caregivers and health professionals.

METHODS

In a 3-round Delphi survey, patients/caregivers and health professionals rated the importance of outcome domains for trials in kidney transplantation on a 9-point Likert scale and provided comments. During rounds 2 and 3, participants rerated the outcomes after reviewing their own score, the distribution of the respondents' scores, and comments. We calculated the median, mean, and proportion rating 7 to 9 (critically important), and analyzed comments thematically.

RESULTS

One thousand eighteen participants (461 [45%] patients/caregivers and 557 [55%] health professionals) from 79 countries completed round 1, and 779 (77%) completed round 3. The top 8 outcomes that met the consensus criteria in round 3 (mean, ≥7.5; median, ≥8; proportion, >85%) in both groups were graft loss, graft function, chronic rejection, acute rejection, mortality, infection, cancer (excluding skin), and cardiovascular disease. Compared with health professionals, patients/caregivers gave higher priority to 6 outcomes (mean difference of 0.5 or more): skin cancer, surgical complications, cognition, blood pressure, depression, and ability to work. We identified 5 themes: capacity to control and inevitability, personal relevance, debilitating repercussions, gaining awareness of risks, and addressing knowledge gaps.

CONCLUSIONS

Graft complications and severe comorbidities were critically important for both stakeholder groups. These stakeholder-prioritized outcomes will inform the core outcome set to improve the consistency and relevance of trials in kidney transplantation.

Orthogonal Comparison of Molecular Signatures of Kidney Transplants With Subclinical and Clinical Acute Rejection: Equivalent Performance Is Agnostic to Both Technology and Platform

We performed orthogonal technology comparisons of concurrent peripheral blood and biopsy tissue samples from 69 kidney transplant recipients who underwent comprehensive algorithm-driven clinical phenotyping. The sample cohort included patients with normal protocol biopsies and stable transplant (sTx) function (n = 25), subclinical acute rejection (subAR, n = 23), and clinical acute rejection (cAR, n = 21). Comparisons between microarray and RNA sequencing (RNA-seq) signatures were performed and demonstrated a strong correlation between the blood and tissue compartments for both technology platforms. A number of shared differentially expressed genes and pathways between subAR and cAR in both platforms strongly suggest that these two clinical phenotypes form a continuum of alloimmune activation. SubAR is associated with fewer or less expressed genes than cAR in blood, whereas in biopsy tissues, this clinical phenotype demonstrates a more robust molecular signature for both platforms. The discovery work done in this study confirms a clear ability to detect gene expression profiles for sTx, subAR, and cAR in both blood and biopsy tissue, yielding equivalent predictive performance that is agnostic to both technology and platform. Our data also provide strong biological insights into the molecular mechanisms underlying these signatures, underscoring their logistical potential as molecular diagnostics to improve clinical outcomes following kidney transplantation.

Emerging drugs for prevention of T-cell mediated rejection in liver and kidney transplantation

INTRODUCTION

Acute and chronic graft rejection continues to be an important problem after solid organ transplantation. With the introduction of potent immunosuppressive agents such as calcineurin inhibitors, the risk of rejection has been significantly reduced. However, the adverse effects of life-long immunosuppression remain a concern, and there exist a fine balance between over-immunosuppression and risk of rejection. Areas covered: In this review, the current standard of care in immunosuppressive therapy, including the use of steroids, calcineurin inhibitors, mycophenolate prodrugs and mammalian target of rapamycin inhibitors, will be discussed. Newer immunosuppressive agents showing promising early data after liver and kidney transplantation will also be explored. Expert Opinion: Currently, calcineurin inhibitors continue to be a vital component of immunosuppressive therapy after solid organ transplantation. Although minimization and avoidance strategies have been developed, the ultimate goal of inducing tolerance remains elusive. Newer emerging agents should have potent and specific immunosuppressive activity, with minimal associated side effects. An individualized approach should be adopted to tailor immunosuppression according to the different needs of recipients.

Application of Operational Tolerance Signatures Are Limited by Variability and Type of Immunosuppression in Renal Transplant Recipients: A Cross-Sectional Study

Supplemental digital content is available in the text.

Background

Renal transplant recipients (RTR) frequently develop complications relating to chronic immunosuppression. Identifying RTR who could safely reduce immunosuppression is therefore highly desirable. We hypothesized that “signatures” described in RTR who have stopped immunosuppression but maintained stable graft function (“operational tolerance”) may enable identification of immunosuppressed RTR who are candidates for immunosuppression minimization. However, the effect of immunosuppression itself on these signatures and circulating B-cell populations is currently unknown.

Methods

We undertook a cross-sectional study of 117 RTR to assess the effect of immunosuppression upon circulating B cell populations, humoral alloresponse and 2 previously published “signatures” of operational tolerance.

Results

Immunosuppression associated with alterations in both published “signatures.” Azathioprine associated with a decrease in transitional and naive B-cell numbers and calcineurin inhibition associated with an increase in the number of circulating plasmablasts. However, only azathioprine use associated with the presence of donor-specific anti-HLA IgG antibodies. Calcineurin inhibition associated with an increase in total serum IgM but not IgG. Data were corrected for age, time since last transplant, and other immunosuppression.

Conclusions

Current signatures of operational tolerance may be significantly affected by immunosuppressive regimen, which may hinder use in their current form in clinical practice. Calcineurin inhibition may prevent the development of long-lasting humoral alloresponses, whereas azathioprine therapy may be associated with donor specific antibody development.

Acetylsalicylic Acid Resistance After Simultaneous Pancreas-Kidney Transplantation

BACKGROUND

The most common conditions leading to death after simultaneous pancreas-kidney transplantations (SPKs) are cardiovascular diseases. The aim of this study was to test the platelet aggregation inhibitor acetylsalicylic acid (ASA) resistance in patients after SPKs, including investigations into the triggering factors.

METHODS

Thirty-two patients (22 men, 10 women; overall age, 47.4 ± 8.6 years) were involved in our study and took 100 mg ASA per day. We used optical platelet aggregometry to detect resistance.

RESULTS

Resistance occurred in 40.6% of the study group. However, with the use of logistic regression analysis, the examined 24 factors did not show any significant correspondence with resistance.

CONCLUSIONS

The incidence of ASA resistance seems to be higher compared with other groups, but the triggering effect is still unproved. Clarifying this question should be important regarding the mortality- and morbidity-reducing capacity of antiplatelet drugs in the management of cardiovascular conditions.

Impaired P2Y12 inhibition by clopidogrel in kidney transplant recipients: results from a cohort study

Background

Cardiovascular complications represent a major cause of morbidity and mortality for patients who received kidney transplantation (KT). However, the impact of KT and chronic immunosuppression on platelet response to clopidogrel in patients undergoing coronary or peripheral revascularization procedures remains unclear. This cohort study compares platelet responsiveness to clopidogrel as assessed byvasodilator-stimulated phosphoprotein (VASP) phosphorylation.

Methods

The study population was divided between chronic kidney disease (CKD) patients who underwent KT (n = 36) and non-transplanted CKD patients (control group, n = 126). Patients were on maintenance antiplatelet therapy with clopidogrel 75 mg daily for at least 8 days. The mean platelet reactivity index (PRI) VASP values and the prevalence of high on-treatment platelet reactivity (HPR, defined as PRI VASP ≥61 %) were compared.

Results

The mean PRI VASP value was significantly higher in the transplant group (60.1 ± 3 vs 51.2 ± 1.6 %; p=0.014). HPR was significantly more common in the transplant group on clopidogrel maintenance therapy (58 vs. 31 %; p = 0.011). KT was the only independent predictor of HPR (odds ratio: 2.6; 95 % confidence interval: 1.03–6.27, p = 0.03). The effect of treatment with calcineurin inhibitors on clopidogrel response could not be analyzed separately from the kidney transplant status.

Conclusions

KT is associated with an increased prevalence of HPR. Our results suggest that plateletfunction tests may be clinically useful for the management of this specific population.