Recent Advances and Clinical Outcomes of Kidney Transplantation

Better kidney allograft survival despite higher-risk donor and recipient characteristics between 1995 and 2014

BACKGROUND AND HYPOTHESIS

Advances in organ procurement, surgical techniques, immunosuppression regimens, and prophylactic antibiotic therapies have dramatically improved kidney transplant graft failure. It is unclear how these interventions have affected longer-term graft failure. It is hypothesized that graft failure has improved over the last 20 years.

METHODS

Data on all first kidney transplants from 1995 to 2014 were extracted from the Australia and New Zealand Dialysis and Transplant Registry with follow-up as of 31 December 2021. Primary exposure was transplant era, classified into 5-year intervals. Primary outcome was all-cause 5-year graft failure. Secondary outcomes included all-cause 10-year graft failure and cause-specific graft failure. Kaplan-Meier curves and multivariable Cox proportional hazards regression models were used to assess trends in all-cause graft failure. Fine-Gray subdistribution hazard models verified that changes in death rates were not biasing the Cox proportional hazards regression models. Cumulative incidence functions were used to assess temporal trends in cause-specific graft failure.

RESULTS

Across 10 871 kidney transplants, there was a shift towards transplanting more recipients aged >45 years old, with more comorbidities, longer dialysis vintage, body mass index >30 kg/m2, and greater human leukocyte antigen mismatches. Donor age has increased but no clear shift in donor source was observed. Compared to 1995-99 (reference), the adjusted hazard ratio for 5-year graft failure was 0.78 (95% CI 0.67-0.91), 0.70 (95% CI 0.59-0.83), and 0.60 (95% CI 0.50-0.73) for 2000-04, 2005-09, and 2010-14, respectively. Ten-year graft failure similarly reduced from 0.83 (95% CI 0.74-0.93) for 2000-04 to 0.78 (95% CI 0.68-0.89) for 2010-14, compared to 1995-99.

CONCLUSION

Medium- and long-term all-cause graft failure has improved steadily since 1995-99. Significant reductions in graft failure due to rejection and vascular causes were observed at 5 years, and due to rejection, vascular causes, death, and glomerular disease at 10 years.

The Relationship between Sclerostin and Kidney Transplantation Mineral Bone Disorders: A Molecule of Controversies

Kidney transplantation is the most effective treatment option for most patients with end-stage kidney disease due to reduced mortality, decreased cardiovascular events and increased quality of life compared to patients treated with dialysis. However, kidney transplantation is not devoid of both acute and chronic complications including mineral bone disorders (MBD) which are already present in patients with chronic kidney disease (CKD) before kidney transplantation. The natural history of MBD after kidney transplantation is variable and new markers are needed to define MBD after kidney transplantation. One of these promising molecules is sclerostin. The main action of sclerostin is to inhibit bone formation and mineralization by blocking osteoblast differentiation and function. In kidney transplant recipients (KTRs), various studies have shown that sclerostin is associated with graft function, bone parameters, vascular calcification, and arterial stiffness although non-uniformly. Furthermore, data for inhibition of sclerostin with monoclonal antibody romosozumab for treatment of osteoporosis is available for general population but not in KTRs which osteoporosis is highly prevalent. In this narrative review, we have summarized the studies investigating the change of sclerostin before and after kidney transplantation, the relationship between sclerostin and laboratory parameters, bone metabolism and vascular calcification in the context of kidney transplantation. We also pointed out the uncertainties, explained the causes of divergent findings and suggest further potential study topics regarding sclerostin in kidney transplantation.

Donor genetic burden for cerebrovascular risk and kidney transplant outcome

BACKGROUND AND HYPOTHESIS

Kidney grafts from donors who died of stroke and related traits have worse outcomes relative to grafts from both living donors and those who died of other causes. We hypothesise that deceased donors, particularly those who died of stroke, have elevated polygenic burden for cerebrovascular traits. We further hypothesise that this donor polygenic burden is associated with inferior graft outcomes in the recipient.

METHODS

Using a dataset of 6666 deceased and living kidney donors from seven different European ancestry transplant cohorts, we investigated the role of polygenic burden for cerebrovascular traits (hypertension, stroke, and intracranial aneurysm (IA)) on donor age of death and recipient graft outcomes.

RESULTS

We found that kidney donors who died of stroke had elevated intracranial aneurysm and hypertension polygenic risk scores, compared to healthy controls and living donors. This burden was associated with age of death among donors who died of stroke. Increased donor polygenic risk for hypertension was associated with reduced long term graft survival (HR: 1.44, 95% CI [1.07, 1.93]) and increased burden for hypertension, and intracranial aneurysm was associated with reduced recipient estimated glomerular filtration rate (eGFR) at 1 year.

CONCLUSIONS

Collectively, the results presented here demonstrate the impact of inherited factors associated with donors' death on long-term graft function.

Arteriovenous fistula for haemodialysis as a predictor of de novo heart failure in kidney transplant recipients

Background

The haemodynamic effects of a functioning haemodialysis arteriovenous fistula (AVF) can cause or exacerbate heart failure (HF). We investigated whether the presence of an AVF at the time of kidney transplant (KT) is associated with de novo HF.

Methods

This was an observational cohort study including adult patients who received a KT in the West of Scotland between 2010 and 2020. We evaluated the risk and associations of pretransplant factors with de novo HF, alone and as a composite cardiovascular (CV) outcome (including non-fatal myocardial infarction, non-fatal stroke, de novo HF and CV death). Multivariable proportional hazards regression and sensitivity analyses were used to identify independent correlates of the outcomes.

Results

Among 1330 included patients, the incident rate of de novo HF after transplantation was 58/1000 person-years [95% confidence interval (CI) 50-67] in AVF patients (n = 716) compared with 33/1000 person-years (95% CI 27-41) in non-AVF patients (n = 614). De novo HF was associated with the presence of an AVF [adjusted hazard ratio (aHR) 2.14 (95% CI 1.40-3.26)], duration of dialysis [aHR 1.03/year increase (95% CI 1.01-1.04)], age at transplant [aHR 1.03/year increase (95% CI 1.02-1.05)], female sex [aHR 1.93 (95% CI 1.40-2.65)] and pretransplant diabetes [aHR 2.43 (95% CI 1.48-4.01)]. The presence of an AVF was also associated with the composite CV outcome [aHR 1.91 (95% CI 1.31-2.78)].

Conclusions

The presence of an AVF may be an underrecognized modifiable predictor of de novo HF posttransplantation.

Prediction of Early Kidney Transplant Graft Outcome: Insulin Resistance Index

BACKGROUND

New-onset diabetes after transplantation and increased insulin resistance have both been shown to affect graft performance and survival after kidney transplantation. Thus, we aimed to evaluate the predictive roles of different insulin resistance indices on early graft function in kidney transplant recipients.

MATERIALS AND METHODS

We conducted a retrospective analysis of non-diabetic patients who received kidney transplantation between January 1, 2018 and December 31, 2021. The primary outcome was the predictive role of different insulin resistance indices on early graft function of serum creatinine level and estimated glomerular filtration rate at 1, 3, 6, and 12 months. The secondary outcome analyzed was the possible clinical predictive factors for poor kidney graft function at 12 months.

RESULTS

Among 123 kidney transplantation patients, stratification with homeostatic model assessment for insulin resistance showed no significant difference in kidney graft function outcome at 1, 3, 6, and 12 months. However, patients with a higher insulin-to-glucose ratio exhibited a significantly higher serum creatinine level at 3 and 6 months and a significantly lower estimated glomerular filtration rate level at 3, 6, and 12 months. Using multivariate logistic regression analysis, patients with a higher insulin-to-glucose ratio were associated with a poorer kidney graft function 12 months after transplantation.

CONCLUSION

Patients with a higher baseline insulin resistance with an insulin-to-glucose ratio ≥of 0.092 exhibited a significantly worse early kidney graft function. Thus, with the identification of patients with increased insulin resistance, early intervention, and preventive measures can be implemented to enhance graft performance further.

Frequency of skin diseases in renal transplant recipients and patients with chronic kidney disease in a tertiary center: a cross-sectional study

BACKGROUND

The prevalence of chronic kidney disease (CKD) has increased in the recent decades, along with the number of patients in the terminal stages of this disease, requiring transplantation. Some skin disorders are more frequent in patients with CKD and in renal transplant recipients (RTR).

OBJECTIVES

To evaluate the frequency of skin diseases in RTR and patients with CKD receiving conservative treatment.

DESIGN AND SETTING

This observational cross-sectional study recruited consecutive patients with CKD and RTR from a nephrology clinic at a teaching hospital in Brazil between 2015 and 2020.

METHODS

Quantitative, descriptive, and analytical approaches were used. The sample was selected based on convenience sampling. Data were collected from dermatological visits and participants' medical records.

RESULTS

Overall, 308 participants were included: 206 RTR (66.9%, median age: 48 years, interquartile range [IQR] 38.0-56.0, 63.6% men) and 102 patients with CKD (33.1%, median age: 61.0 years, IQR 50.0-71.2, 48% men). The frequency of infectious skin diseases (39.3% vs. 21.6% P = 0.002) were higher in RTR than in patients with CKD. Neoplastic skin lesions were present in nine (4.4%) RTR and in only one (1.0%) patient with CKD. Among the RTR, the ratio of basal cell carcinoma to squamous cell carcinoma was 2:1.

CONCLUSIONS

This study revealed that an increased frequency of infectious skin diseases may be expected in patients who have undergone kidney transplantation. Among skin cancers, BCC is more frequently observed in RTR, especially in those using azathioprine.

Evolving Trends in Kidney Transplant Outcomes Among Older Adults: A Comparative Analysis Before and During the COVID-19 Pandemic

Background

Advancements in medical technology, healthcare delivery, and organ allocation resulted in improved patient/graft survival for older (age ≥65) kidney transplant (KT) recipients. However, the recent trends in these post-KT outcomes are uncertain in light of the mounting burden of cardiovascular disease, changing kidney allocation policies, heterogeneity in candidates' risk profile, and the coronavirus disease 2019 pandemic. Thus, we examined secular trends in post-KT outcomes among older and younger KT recipients over the last 3 decades.

Methods

We identified 73 078 older and 378 800 younger adult (aged 18-64) recipients using Scientific Registry of Transplant Recipients (1990-2022). KTs were grouped into 6 prepandemic eras and 1 postpandemic-onset era. Kaplan-Meier and Cox proportional hazards models were used to examine temporal trends in post-KT mortality and death-censored graft failure.

Results

From 1990 to 2022, a 19-fold increase in the proportion of older KT recipients was observed compared to a 2-fold increase in younger adults despite a slight decline in the absolute number of older recipients in 2020. The mortality risk for older recipients between 2015 and March 14, 2020, was 39% (adjusted hazard ratio [aHR] = 0.61, 95% confidence interval [CI], 0.50-0.75) lower compared to 1990-1994, whereas that for younger adults was 47% lower (aHR = 0.53, 95% CI, 0.48-0.59). However, mortality risk during the pandemic was 25% lower (aHR = 0.75, 95% CI, 0.61-0.93) in older adults and 37% lower in younger adults (aHR = 0.63, 95% CI, 0.56-0.70) relative to 1990-1994. For both populations, the risk of graft failure declined over time and was unaffected during the pandemic relative to the preceding period.

Conclusions

The steady improvements in 5-y mortality and graft survival were disrupted during the pandemic, particularly among older adults. Specifically, mortality among older adults reflected rates seen 20 y prior.

MCP1 Inverts the Correlation between FGF23 and Omega 6/3 Ratio: Is It Also True in Renal Transplantation?

During chronic kidney disease (CKD) progression, an increase in fibroblast growth factor (FGF23) is present. In stage 5, a positive correlation between FGF23 and omega-6 (n-6) polyunsaturated fatty acids (PUFAs) emerges. Hypothesizing that the rising positive correlation between monocyte chemoattractant protein 1 (MCP1) and n-6 in stage 4 could be the cause, we previously explored FGF23 and MCP1's roles in dyslipidemia and cardiovascular risk in CKD. In the present paper, we retraced the study evaluating 40 kidney transplant patients (KTx), a cohort where several factors might modify the previous relationships found. An ELISA and gas chromatography assessed the MCP1, FGF23, and PUFA levels. Despite the FGF23 increase (p < 0.0001), low MCP1 levels were found. A decrease in the n-6/n-3 ratio (p = 0.042 CKD stage 4 vs. 5) lowered by the increase in both n-3 αlinolenic (p = 0.012) and docosapentaenoic acid (p = 0.049) was observed. A negative correlation between FGF23 and the n-6/n-3 ratio in CKD stage 4 (r2 -0.3 p = 0.043) and none with MCP1 appeared. According to our findings, different mechanisms in the relationship between FGF23, PUFAs, and MCP1 in CKD and KTx patients might be present, which is possibly related to the immunosuppressive status of the last. Future research will further clarify our hypothesis.

Tuberculosis in Kidney Transplant Recipients: A Nationwide Cohort in a Low Tuberculosis Incidence Country

Background

World Health Organization recommends tuberculosis (TB) preventive treatment for risk groups such as patients preparing for organ transplantation. Pretransplant screening or treatment of latent TB infection has not been routine practice in Finland.

Methods

In this nationwide registry study, we assessed the risk of TB among kidney transplant recipients compared to the general population. TB cases were identified by data linkage of the national infectious disease and the national transplant registries between 1995 and 2019. Standardized incidence ratios were calculated with adjustment for age, sex, and annual TB dynamics.

Results

A total of 4101 kidney transplants in 3900 recipients with a follow-up of 37 652 patient-years were included. Eighteen TB cases were detected. Patients diagnosed with TB were older (median age 64 y, interquartile range 56-66) at transplantation than those without TB (median 51 y, interquartile range 41-60, P < 0.001). The standardized incidence ratio of TB was 6.9 among kidney transplant recipients compared to general population during the whole study period 1995-2019 but decreased from 12.5 in 1995-2007 to 3.2 in 2008-2019. The standardized incidence ratio was 44.2 during the first year after transplantation. Significant differences in 5-y graft losses were not detected between TB patients and those without TB.

Conclusions

The standardized incidence ratio of TB in kidney transplant recipients has decreased over the years, but these patients remain at risk of TB, especially during the first posttransplant year. Cost-benefit analysis is required to address feasibility of latent TB infection screening among transplant candidates in countries with low incidence of TB.

Predictor factor for worse outcomes in kidney transplant recipients infected with coronavirus disease 2019: A systematic review and meta-analysis

INTRODUCTION

The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a massive impact on the health sector, especially in patients with pre-existing comorbidities. This study aims to define the predictor factors for worse outcomes in kidney transplant patients infected with SARS-CoV-2 and affected by coronavirus disease 2019 (COVID-19). We have analyzed in these patients their prior medical history, their clinical symptoms, and their laboratory results.

METHOD

We assessed outcomes of kidney transplant patients with confirmed COVID-19 until July 2021 from PubMed, Medline, Science Direct, Cochrane databases, EMBASE, Scopus, and EBSCO. We performed meta-analyses of nine published studies to estimate predictor factors. The analysis was analyzed by the Newcastle-Ottawa Scale (NOS) and then using the Review Manager 5.4 software.

RESULT

Our analysis demonstrated that the most significant risk factors for the worse COVID-19 outcomes for kidney transplant patients included: age of 60 and older [MD 9.31(95% CI, 6.31-12.30), p < 0.0001, I2 = 76%], diabetic nephropathy [OR 2.13 (95% CI, 1.49-3.04), p < 0.0001, I2 = 76%], dyspnea [OR 4.53, (95% CI, 2.22-9.22), p < 0.0001, I2 = 76%], acute kidney injury (AKI) [OR 4.53 (95% CI, 1.10-5.21), p = 0.03, I2 = 58%], and some laboratory markers. Many patients had two or multiple risk factors in combination.

CONCLUSION

Age and several comorbidities were the most significant factors for COVID-19 outcomes for kidney transplant recipients.

The Gut Microbiota in Kidney Transplantation: A Target for Personalized Therapy?

Kidney transplantation improves quality of life, morbidity, and mortality of patients with kidney failure. However, integrated immunosuppressive therapy required to preserve graft function is associated with the development of post-transplant complications, including infections, altered immunosuppressive metabolism, gastrointestinal toxicity, and diarrhea. The gut microbiota has emerged as a potential therapeutic target for personalizing immunosuppressive therapy and managing post-transplant complications. This review reports current evidence on gut microbial dysbiosis in kidney transplant recipients, alterations in their gut microbiota associated with kidney transplantation outcomes, and the application of gut microbiota intervention therapies in treating post-transplant complications.

Robotic-assisted versus laparoscopic living donor nephrectomy for renal transplantation: a systematic review and meta-analysis

INTRODUCTION

Renal transplantation remains the definitive treatment for end-stage renal disease. Currently employed minimally invasive techniques include robotic-assisted laparoscopy and laparoscopy. This study aims to determine whether either method provides an advantage.

METHODS

Following PRISMA guidelines, a systematic review was conducted. Data were analysed using Review Manager 5.3.

RESULTS

A total of 12 studies were included. Operative time and operative bleeding were similar between both approaches, with a mean difference (MD) of 16min (95% confidence interval (CI) -4.06, 37.38; p = 0.11) and 10.44ml (95% CI -43.89, 64.78; p = 0.71), respectively. Robotics had longer warm ischemia time (MD 1.14min; 95% CI 0.65, 1.63; p = 0.00001) but reduced length of stay (LOS) (MD -0.23days; 95% CI -0.45, -0.01; p = 0.04) and pain (MD -1.26 VAS; 95% CI -1.77, 0.75). Similar complication and conversion rates were seen among groups.

CONCLUSIONS

Robotic approaches provide a viable alternative to laparoscopic surgery. Operative time, bleeding volumes, complications and conversion rates are similar between both techniques; apparent robotic advantages on LOS and Pain need to be better analysed by future studies.

The Kidney Transplant Self-Management Scale: Instrument Development and Psychometric Testing

This study reports the development and psychometric testing of the Kidney Transplant Self-Management Scale (KT-SMS). The instrument development phase included the following: (a) conceptual definition, item generation, and framework; (b) face validity assessment; and (c) content validity assessment. The psychometric testing phase included the following: (a) construct validity testing; (b) internal consistency reliability testing; (c) convergent validity testing; and (d) predictive power of the KT-SMS using a cross-sectional sample of kidney transplant recipients (N = 153). Factor analysis results supported the 16-item KT-SMS as multidimensional with five domains (medication adherence, cardiovascular risk reduction, protecting kidney, ownership, and skin cancer prevention). Internal consistency reliability for the total scale and five subscales was adequate. Convergent validity was supported as the intercorrelations of the KT-SMS total score with the five subscales were significant. The KT-SMS total score and five subscales were significantly correlated with self-efficacy for managing chronic disease, patient activation, and health-related quality of life.

Afucosylation of HLA-specific IgG1 as a potential predictor of antibody pathogenicity in kidney transplantation

Antibody-mediated rejection (AMR) is the leading cause of graft failure. While donor-specific antibodies (DSAs) are associated with a higher risk of AMR, not all patients with DSAs develop rejection, suggesting that the characteristics of alloantibodies determining their pathogenicity remain undefined. Using human leukocyte antigen (HLA)-A2-specific antibodies as a model, we apply systems serology tools to investigate qualitative features of immunoglobulin G (IgG) alloantibodies including Fc-glycosylation patterns and FcγR-binding properties. Levels of afucosylated anti-A2 antibodies are elevated in seropositive patients, especially those with AMR, suggesting potential cytotoxicity via FcγRIII-mediated mechanisms. Afucosylation of both glycoengineered monoclonal and naturally glycovariant polyclonal serum IgG specific to HLA-A2 drives potentiated binding to, slower dissociation from, and enhanced signaling through FcγRIII, a receptor widely expressed on innate effector cells, and greater cytotoxicity against HLA-A2+ cells mediated by natural killer (NK) cells. Collectively, these results suggest that afucosylated DSA may be a biomarker of AMR and contribute to pathogenesis.

Could thymoglobulin increase hemorrhagic risk in the perioperative transplantation period of sensitized kidney recipients?

OBJECTIVE

It has been described that thymoglobulin could increase the risk of infections and malignancies, in comparison to basiliximab. Leukopenia and thrombocytopenia are also more common within the first days after transplantation among thymoglobulin patients. Our objective was to analyze bleeding complications in this subset of patients.

MATERIAL AND METHODS

Bleeding complications were evaluated among 515 renal transplants carried out at our institution between 2012 and 2018. We compared patients treated with thymoglobulin (Group 1, N=91) with those treated with basiliximab (Group 2, N=424).

RESULTS

We found differences in platelet decrease: 95,142.2 (55,339.6) in Group 1 and 52,364.3 (69,116.6) in Group 2 (P=0.001), number of patients with severe thrombocytopenia (<75,000/mm³) (20.8% vs. 3.7%, P=0.001), number of blood units transfused (3.25 (0.572) vs. 2.2 (0.191, P=0.028) and percentage of patients that required surgery due to bleeding (18.2% vs. 7.7%, P=0.046). In a multiple lineal regression multivariable analysis (dependent variable was number of blood units transfused), only age [OR 0.037, 95% CI (0.003-0.070)] and type of immunosuppression [OR 1.592, 95% CI (1.38-2.84)] showed statistical significance.

CONCLUSIONS

The use of thymoglobulin in the perioperative transplantation period could increase bleeding complications. In our series, in the group of patients with thymoglobulin, severe thrombocytopenia was 6 times more frequent, and active bleeding that required surgery was also 2.5 times more frequent. One way to continue with the use of this immunosuppression agent, might be to adjust the dose instead of discontinuing it. The use of thymoglobulin should be a factor to consider in the postoperative period of these patients.

Kidney Transplant-Associated Viral Infection Rates and Outcomes in a Single-Centre Cohort

BACKGROUND

Opportunistic infections remain a significant cause of morbidity and mortality after kidney transplantation. This retrospective cohort study aimed to assess the incidence and predictors of post-transplant DNA virus infections (CMV, EBV, BKV and JCV infections) in kidney transplant recipients (KTR) at a single tertiary centre and evaluate their impact on graft outcomes.

METHODS

KTR transplanted between 2000 and 2021 were evaluated. Multivariate logistic regression analysis and Cox proportional hazard analyses were used to identify factors associated with DNA virus infections and their impact on allograft outcomes respectively. A sub-analysis of individual viral infections was also conducted to describe the pattern, timing, interventions, and outcomes of individual infections.

RESULTS

Data from 962 recipients were evaluated (Mean age 47.3 ± 15 years, 62% male, 81% white). 30% of recipients (288/962) had infection(s) by one or more of the DNA viruses. Individually, CMV, EBV, BKV and JCV viruses were diagnosed in 13.8%. 11.3%, 8.9% and 4.4% of recipients respectively. Factors associated with increased risk of post-transplant DNA virus infection included recipient female gender, higher number of HLA mismatch, lower baseline estimated glomerular filtration rate (eGFR), CMV seropositive donor, maintenance with cyclosporin (rather than tacrolimus) and higher number of maintenance immunosuppressive medications. The slope of eGFR decline was steeper in recipients with a history of DNA virus infection irrespective of the virus type. Further, GFR declined faster with an increasing number of different viral infections. Death-censored graft loss adjusted for age, gender, total HLA mismatch, baseline eGFR and acute rejection was significantly higher in recipients with a history of DNA virus infection than those without infection (adjusted hazard ratio (aHR, 1.74, 95% CI, 1.08-2.80)). In contrast, dialysis-free survival did not differ between the two groups of recipients (aHR, 1.13, 95% CI, 0.88-1.47).

CONCLUSION

Post-transplant DNA viral infection is associated with a higher risk of allograft loss. Careful management of immunosuppression and close surveillance of at-risk recipients may improve graft outcomes.

Perioperative outcomes and readmissions following cardiac operations in kidney transplant recipients

OBJECTIVE

Although kidney transplant (KTx) recipients are at significant risk for cardiovascular disease, outcomes following cardiac operations have been examined in limited series. The present study thus aimed to assess the impact of KTx on in-hospital perioperative outcomes and readmissions in a nationally representative cohort.

METHODS

All adults undergoing elective coronary artery bypass grafting, valve repair/replacement or a combination thereof were identified from the 2010-2018 Nationwide Readmissions Database. Patients were stratified by history of KTx. Transplant-capable centres were defined as hospitals performing at least one KTx annually. To perform risk-adjustment in assessing outcomes, multivariable regression models were developed.

RESULTS

Of an estimated 1 407 351 patients included for analysis, 0.2% (n=2849) were KTx recipients. Compared with the general cardiac surgical population, patients with prior KTx experienced higher adjusted odds of in-hospital mortality (adjusted OR (AOR) 2.44, 95% CI 1.72 to 3.47, p<0.001) and perioperative complication (AOR 1.67, 95% CI 1.44 to 1.94, p<0.001). Additionally, KTx was independently associated with greater readmission rates within 30 days (AOR 1.96, 95% CI 1.65 to 2.34, p<0.001) with kidney injury contributing significantly to the burden of rehospitalisation (4.6 vs 1.8%, p=0.005). In a subpopulation comprised of only KTx recipients, treatment at a transplant-capable centre reduced odds of kidney injury with non-transplant hospitals as reference (AOR 0.65, 95% CI 0.43 to 0.98, p=0.037).

CONCLUSIONS

Kidney transplant recipients undergoing cardiac operations encounter significant risks compared with the general surgical population. Referral to transplant-capable centres should be explored to improve outcomes and to preserve allograft function in this population.

Validation of a gene expression signature to measure immune quiescence in kidney transplant recipients in the CLIA setting

Aim: Allograft rejection remains a major cause of graft failure in kidney transplantation. Here the authors report the validation of a non-invasive molecular diagnostic assay, AlloMap Kidney, using peripheral blood. Methods: The AlloMap Kidney test is a gene expression profile utilizing the RNA-seq platform to measure immune quiescence in kidney transplant patients. Results/Conclusions: Analytical validation showed robust performance characteristics with an accuracy correlation coefficient of 0.997 and a precision coefficient of variation of 0.049 across testing. Clinical validation from the prospective, multi-center studies of 235 samples (66 rejection and 169 quiescence specimens) demonstrated the sensitivity of 70% and specificity of 66% for allograft rejection, while the negative predictive value was 95% to discriminate rejection from quiescence at 10% prevalence of rejection.

KLF4 Affects Acute Renal Allograft Injury via Binding to MicroRNA-155-5p Promoter to Regulate ERRFI1

Kruppel-like factor 4 (KLF4) owns the promising potential in treating kidney injury, which inevitably occurs during renal allograft. Given that, this research targets to unveil KLF4-oriented mechanism from microRNA-155-5p/ERBB receptor feedback inhibitor 1 (miR-155-5p/ERRFI1) axis in acute renal allograft injury. Mice were injected with miR-155-5p-related sequences before acute renal allograft modeling. Afterwards, serum inflammation, along with oxidative stress, renal tubular injury, and apoptosis in renal tissues were detected. HK-2 cells were processed by hypoxia/reoxygenation (H/R) and transfected with miR-155-5p- or ERRFI1-related sequences, after which cell proliferation and apoptosis were measured. KLF4, miR-155-5p, and ERRFI1 expressions and their interaction were tested. KLF4 and miR-155-5p levels were enhanced, and ERRFI1 level was repressed in mice after acute renal allograft and in H/R-treated HK-2 cells. KLF4 bound to the promoter of miR-155-5p. Depleting miR-155-5p reduced serum inflammation and attenuated oxidative stress, renal tubular injury, and apoptosis in mice with acute renal allograft injury. Downregulating miR-155-5p facilitated proliferation and repressed apoptosis of H/R-treated HK-2 cells. miR-155-5p targeted ERRFI1. Knocking down ERRFI1 antagonized the effects of downregulated miR-155-5p on acute renal allograft injury, as well as on H/R-treated HK-2 cell proliferation and apoptosis. A summary displays that silencing KLF4 suppresses miR-155-5p to attenuate acute renal allograft injury by upregulating ERRFI1, which provides a way to control acute renal allograft injury.

The Application of Nanoparticles in Diagnosis and Treatment of Kidney Diseases

Nanomedicine is currently showing great promise for new methods of diagnosing and treating many diseases, particularly in kidney disease and transplantation. The unique properties of nanoparticles arise from the diversity of size effects, used to design targeted nanoparticles for specific cells or tissues, taking renal clearance and tubular secretion mechanisms into account. The design of surface particles on nanoparticles offers a wide range of possibilities, among which antibodies play an important role. Nanoparticles find applications in encapsulated drug delivery systems containing immunosuppressants and other drugs, in imaging, gene therapies and many other branches of medicine. They have the potential to revolutionize kidney transplantation by reducing and preventing ischemia-reperfusion injury, more efficiently delivering drugs to the graft site while avoiding systemic effects, accurately localizing and visualising the diseased site and enabling continuous monitoring of graft function. So far, there are known nanoparticles with no toxic effects on human tissue, although further studies are still needed to confirm their safety.

Clinicopathologic analysis of malignant or premalignant cutaneous neoplasms in Japanese kidney transplant recipients

It is well known that recipients of kidney transplants are at an increased risk of developing malignant or premalignant cutaneous neoplasms (MPCNs) after transplantation. However, the pathogenesis of MPCNs after kidney transplant has not been well-studied in Asian populations. This study aimed to describe the clinicopathologiccharacteristics of MPCNs in an Asian population. We retrospectively reviewed the medical records of 1956 patients who received kidney transplants at two hospitals in Japan, between 2003 and 2019. Among these patients, 24 developed 50 MPCN lesions, including 14 squamous cell carcinoma (SCC, 28%), 23 Bowen's disease (BD, 46%), 11 actinic keratosis (AK, 22%), and two basal cell carcinoma (BCC, 4%). No patient had malignant melanoma. The duration from transplantation to the diagnosis was significantly longer for SCC than for BD or AK (P=0.021, 0.036, respectively). Seven patients had multiple MPCNs in sun-exposed areas of skin. Among the 50 MPCNs, 40 (80%) were located in sun-exposed areas, and 10 (20%) were located in sun-protected areas. MPCNs in sun-exposed skin were frequently accompanied by dermal solar elastosis (90%, 36/40). We found high-risk human papillomavirus (HR-HPV) infections in two anogenital lesions (100%, 2/2). In contrast, HR-HPV infections were not detected in any extragenital lesions (0%, 0/30). Our results suggested that, among Japanese recipients of kidney transplant, MPCNs in sun-exposed skin areas may be associated with immunosuppression and ultraviolet exposure.

Impact of gut microbiota on kidney transplantation

Kidney transplantation is recognized as one of the most effective treatments for patients who suffer from end-stage renal disease. The major potential outcomes following kidney transplantation include engraftment, rejection, and associated complications. The outcomes are dependent on a variety of factors in those who underwent renal grafts or kidney transplant recipients. Those factors include the administration of immunosuppressive drugs and prophylactic antimicrobial agents to recipients. Recent studies have shown that gut microbiota play an important role in the outcome of subjects with kidney transplantation. An imbalance of the components/diversity of gut microbiota, known as gut dysbiosis, has been shown to have a big impact on the immune system of the host and the modification of host inflammatory cytokines. Although gut dysbiosis is affected by variation in diet and medication, a substantial amount of evidence showing a link between alteration in human gut microbiota and outcomes of kidney transplantation has recently been reported. Therefore, the objective of this review is to comprehensively summarize and discuss the major findings from in vivo and clinical data pertaining to the impact of gut microbiota on kidney transplantation. Any controversial findings are compiled to enable a clear overview of the role of gut microbiota and the outcome of kidney transplantation.

Dialysis patients have comparable results to patients who have received kidney transplant after total joint arthroplasty: a systematic review and meta-analysis

Patients with end-stage renal disease (ESRD) have inferior outcomes after hip and knee total joint arthroplasty (TJA), with higher risk for surgical site complications (SSC) and periprosthetic joint infection (PJI).

We conducted a systematic review and meta-analysis regarding outcomes after hip and knee TJA in ESRD patients who have received dialysis or a kidney transplant (KT) using PubMed, MEDLINE, Cochrane Reviews, and Embase in order to: (1) determine the mortality and infection rate of TJA in patients receiving dialysis or KT and (2) to identify risk factors associated with the outcome.

We included 22 studies and 9384 patients (dialysis, n = 8921, KT, n = 463). The overall mortality rate was 14.9% and was slightly higher in KT patients (dialysis vs. KT, 13.8% vs. 15.8%). The overall SSC rate was 3.4%, while dialysis and KT patients each had an incidence of 3.3% and 3.6%, respectively. For PJI, the overall rate was 3.9%, while the incidence for dialysis patients was 4.0% and for KT patients was 3.7%.

Using multi-regression analysis, age, sex, the type of arthroplasty (knee or hip) performed, and the form of renal replacement therapy (dialysis or KT) were not significant risk factors.

In patients on dialysis or who had received a KT, TJA is associated with a slight increase in mortality, SSC and PJI rates.

Cite this article: EFORT Open Rev 2021;6:618-628. DOI: 10.1302/2058-5241.6.200116

Outcomes of Kidney Transplant Recipients with Sickle Cell Disease: An Analysis of the 2000-2019 UNOS/OPTN Database

Background: Lower patient survival has been observed in sickle cell disease (SCD) patients who go on to receive a kidney transplant. This study aimed to assess the post-transplant outcomes of SCD kidney transplant recipients in the contemporary era. Methods: We used the OPTN/UNOS database to identify first-time kidney transplant recipients from 2010 through 2019. We compared patient and allograft survival between recipients with SCD (n = 105) vs. all other diagnoses (non-SCD, n = 146,325) as the reported cause of end-stage kidney disease. We examined whether post-transplant outcomes improved among SCD in the recent era (2010–2019), compared to the early era (2000–2009). Results: After adjusting for differences in baseline characteristics, SCD was significantly associated with lower patient survival (HR 2.87; 95% CI 1.75–4.68) and death-censored graft survival (HR 1.98; 95% CI 1.30–3.01), compared to non-SCD recipients. The lower patient survival and death-censored graft survival in SCD recipients were consistently observed in comparison to outcomes of recipients with diabetes, glomerular disease, and hypertension as the cause of end-stage kidney disease. There was no significant difference in death censored graft survival (HR 0.99; 95% CI 0.51–1.73, p = 0.98) and patient survival (HR 0.93; 95% CI 0.50–1.74, p = 0.82) of SCD recipients in the recent versus early era. Conclusions: Patient and allograft survival in SCD kidney recipients were worse than recipients with other diagnoses. Overall SCD patient and allograft outcomes in the recent era did not improve from the early era. The findings of our study should not discourage kidney transplantation for ESKD patients with SCD due to a known survival benefit of transplantation compared with remaining on dialysis. Urgent future studies are needed to identify strategies to improve patient and allograft survival in SCD kidney recipients. In addition, it may be reasonable to assign risk adjustment for SCD patients.

Epidemiology of cannabis use and associated outcomes among kidney transplant recipients: A meta-analysis

OBJECTIVE

Cannabis is the most commonly used recreational drug in the United States, and transplant acceptability for cannabis using candidates varies among transplant centers. However, the prevalence and impact of cannabis use on outcomes of kidney transplant recipients remain unclear. This study aimed to summarize the prevalence and impact of cannabis use on outcomes after kidney transplantation.

METHODS

A literature search was performed using Ovid MEDLINE, EMBASE, and The Cochrane Library Databases from inception until September 2019 to identify studies assessing the prevalence of cannabis use among kidney transplant recipients, and reported adverse outcomes after kidney transplantation. Effect estimates from the individual studies were obtained and combined utilizing random-effects, generic inverse variance method of DerSimonian-Laird.

RESULTS

A total of four cohort studies with a total of 55 897 kidney transplant recipients were enrolled. Overall, the pooled estimated prevalence of cannabis use was 3.2% (95% CI 0.4%-20.5%). While the use of cannabis was not significantly associated with all-cause allograft failure (OR = 1.31, 95% CI 0.70-2.46) or mortality (OR = 1.52, 95% CI 0.59-3.92), the use of cannabis among kidney transplant recipients was significantly associated with increased death-censored graft failure with pooled OR of 1.72 (95% CI 1.13-2.60).

CONCLUSIONS

The overall estimated prevalence of cannabis use among kidney transplant recipients is 3.2%. The use of cannabis is associated with increased death-censored graft failure, but not mortality after kidney transplantation.

Development and validation of routine clinical laboratory data derived marker-based nomograms for the prediction of 5-year graft survival in kidney transplant recipients

Background: To develop and validate predictive nomograms for 5-year graft survival in kidney transplant recipients (KTRs) with easily-available laboratory data derived markers and clinical variables within the first year post-transplant.

Methods: The clinical and routine laboratory data from within the first year post-transplant of 1289 KTRs was collected to generate candidate predictors. Univariate and multivariate Cox analyses and LASSO were conducted to select final predictors. X-tile analysis was applied to identify optimal cutoff values to transform potential continuous factors into category variables and stratify patients. C-index, calibration curve, dynamic time-dependent AUC, decision curve analysis, and Kaplan-Meier curves were used to evaluate models’ predictive accuracy and clinical utility.

Results: Two predictive nomograms were constructed by using 0–6- and 0–12- month laboratory data, and showed good predictive performance with C-indexes of 0.78 and 0.85, respectively, in the training cohort. Calibration curves showed that the prediction probabilities of 5-year graft survival were in concordance with actual observations. Additionally, KTRs could be successfully stratified into three risk groups by nomograms.

Conclusions: These predictive nomograms combining demographic and 0–6- or 0–12- month markers derived from post-transplant laboratory data could serve as useful tools for early identification of 5-year graft survival probability in individual KTRs.

CYP3A5 Gene-Guided Tacrolimus Treatment of Living-Donor Egyptian Kidney Transplanted Patients

Background

Tacrolimus is an approved first-line immunosuppressive agent for kidney transplantations. Part of interindividual and interethnic differences in the response of patients to tacrolimus is attributed to polymorphisms at CYP3A5 metabolic enzyme. CYP3A5 gene expression status is associated with tacrolimus dose requirement in renal transplant recipients.

Materials and Methods

In this study, we determined the allelic frequency of CYP3A5*3 in 76 renal transplanted patients of Egyptian descent. Secondly, we evaluated the influence of the CYP3A5 gene variant on tacrolimus doses required for these patients as well on dose-adjusted tacrolimus trough-concentrations.

Results

The CYP3A5*3 variant was the most frequent allele detected at 85.53%. Additionally, our results showed that, mean tacrolimus daily requirements for heterozygous patients (CYP3A5*1/*3) were significantly higher compared to homozygous patients (CYP3A5*3/*3) during the first year after kidney transplantation.

Conclusion

This is the first study in Egypt contributing to the individualization of tacrolimus dosing in Egyptian patients, informed by the CYP3A5 genotype.

Serum Klotho in Living Kidney Donors and Kidney Transplant Recipients: A Meta-Analysis

α-Klotho is a known anti-aging protein that exerts diverse physiological effects, including phosphate homeostasis. Klotho expression occurs predominantly in the kidney and is significantly decreased in patients with chronic kidney disease. However, changes in serum klotho levels and impacts of klotho on outcomes among kidney transplant (KTx) recipients and kidney donors remain unclear. A literature search was conducted using MEDLINE, EMBASE, and Cochrane Database from inception through October 2019 to identify studies evaluating serum klotho levels and impacts of klotho on outcomes among KTx recipients and kidney donors. Study results were pooled and analyzed utilizing a random-effects model. Ten cohort studies with a total of 431 KTx recipients and 5 cohort studies with a total of 108 living kidney donors and were identified. After KTx, recipients had a significant increase in serum klotho levels (at 4 to 13 months post-KTx) with a mean difference (MD) of 243.11 pg/mL (three studies; 95% CI 67.41 to 418.81 pg/mL). Although KTx recipients had a lower serum klotho level with a MD of = -234.50 pg/mL (five studies; 95% CI -444.84 to -24.16 pg/mL) compared to healthy unmatched volunteers, one study demonstrated comparable klotho levels between KTx recipients and eGFR-matched controls. Among kidney donors, there was a significant decrease in serum klotho levels post-nephrectomy (day 3 to day 5) with a mean difference (MD) of -232.24 pg/mL (three studies; 95% CI -299.41 to -165.07 pg/mL). At one year following kidney donation, serum klotho levels remained lower than baseline before nephrectomy with a MD of = -110.80 pg/mL (two studies; 95% CI 166.35 to 55.24 pg/mL). Compared to healthy volunteers, living kidney donors had lower serum klotho levels with a MD of = -92.41 pg/mL (two studies; 95% CI -180.53 to -4.29 pg/mL). There is a significant reduction in serum klotho levels after living kidney donation and an increase in serum klotho levels after KTx. Future prospective studies are needed to assess the impact of changes in klotho on clinical outcomes in KTx recipients and living kidney donors.

The Use of Donor-Derived Cell-Free DNA for Assessment of Allograft Rejection and Injury Status

Patient monitoring after kidney transplantation (KT) for early detection of allograft rejection remains key in preventing allograft loss. Serum creatinine has poor predictive value to detect ongoing active rejection as its increase is not sensitive, nor specific for acute renal allograft rejection. Diagnosis of acute rejection requires allograft biopsy and histological assessment, which can be logistically challenging in some cases and carries inherent risk for complications related to procedure. Donor-derived cell-free DNA (dd-cfDNA), DNA of donor origin in the blood of KT recipient arising from cells undergoing injury and death, has been examined as a potential surrogate marker for allograft rejection. A rise in dd-cfDNA levels precedes changes in serum creatinine allows early detections and use as a screening tool for allograft rejection. In addition, when used in conjunction with donor-specific antibodies (DSA), it increases the pre-biopsy probability of antibody-mediated rejection (ABMR) aiding the decision-making process. Advancements in noninvasive biomarker assays such as dd-cfDNA may offer the opportunity to improve and expand the spectrum of available diagnostic tools to monitor and detect risk for rejection and positively impact outcomes for KT recipients. In this this article, we discussed the evolution of dd-cfDNA assays and recent evidence of assessment of allograft rejection and injury status of KT by the use of dd-cfDNA.

Degree of Glomerulosclerosis in Procurement Kidney Biopsies from Marginal Donor Kidneys and Their Implications in Predicting Graft Outcomes

Background: This study aimed to assess the association between the percentage of glomerulosclerosis (GS) in procurement allograft biopsies from high-risk deceased donor and graft outcomes in kidney transplant recipients. Methods: The UNOS database was used to identify deceased-donor kidneys with a kidney donor profile index (KDPI) score > 85% from 2005 to 2014. Deceased donor kidneys were categorized based on the percentage of GS: 0-10%, 11-20%, >20% and no biopsy performed. The outcome included death-censored graft survival, patient survival, rate of delayed graft function, and 1-year acute rejection. Results: Of 22,006 kidneys, 91.2% were biopsied showing 0-10% GS (58.0%), 11-20% GS (13.5%), >20% GS (19.7%); 8.8% were not biopsied. The rate of kidney discard was 48.5%; 33.6% in 0-10% GS, 68.9% in 11-20% GS, and 77.4% in >20% GS. 49.8% of kidneys were discarded in those that were not biopsied. Death-censored graft survival at 5 years was 75.8% for 0-10% GS, 70.9% for >10% GS, and 74.8% for the no biopsy group. Among kidneys with >10% GS, there was no significant difference in death-censored graft survival between 11-20% GS and >20% GS. Recipients with >10% GS had an increased risk of graft failure (HR = 1.27, p < 0.001), compared with 0-10% GS. There was no significant difference in patient survival, acute rejection at 1-year, and delayed graft function between 0% and 10% GS and >10% GS. Conclusion: In >85% KDPI kidneys, our study suggested that discard rates increased with higher percentages of GS, and GS >10% is an independent prognostic factor for graft failure. Due to organ shortage, future studies are needed to identify strategies to use these marginal kidneys safely and improve outcomes.