Injury In Renal Transplantation Research Articles

A clinical study of using ROC to compare the efficiency of ASL and BOLD in diagnosis of renal allograft function.

This retrospective study aims to evaluate the effectiveness of renal transplantation function by comparing arterial spin labeling (ASL) and blood oxygen level dependent (BOLD) imaging with the receiver operating characteristic (ROC) curve. According to the estimated glomerular filtration rate (eGFR) values, 42 patients with normal kidney grafts (the normal kidney graft group, eGFR <60 mL/min/1.73 m2) and 93 patients with injured grafts (the kidney graft injury group, eGFR <60 mL/min/1.73 m2) were included in the present study. Renal blood flow (RBF) and the effective transverse relaxation rate (R2*) were calculated by comparing ASL and BOLD imaging. The ROC curve and the youden index were used to evaluate the diagnostic performance of ASL, BOLD, and the combination of them. The results showed that all the clinical features of the patients, except for gender, differed significantly between the 2 groups (P<0.05). The mean RBF value of the renal transplant injury group (104.33±54.76 mL/100 g/min) was significantly lower than that of the normal group (191.84±63.96 mL/100 g/min, P<0.01). The mean medullary R2* value of the renal transplant injury group (27.91±3.35 1/s) was significantly higher than that of the normal group (25.22±2.94 1/s, P<0.01). Negative correlations were found between R2* and eGFR (r=-0.44), and RBF and R2* (r=-0.54; both P<0.01). The ROC analysis showed that both RBF and R2* reflected injured renal function [area under the curves (AUC) =0.86 and 0.72, respectively]. In addition, the AUC of RBF and R2* combined was 0.86, which was comparable to that of RBF alone (P=0.95), while combining R2* and RBF improved the diagnostic performance of R2* alone (AUC =0.86 versus 0.72, respectively; P<0.01). The youden index analysis showed that the diagnostic accuracy of ASL was 80.00%, better than 71.85% of BOLD; the sensitivity and specificity of ASL in diagnosing renal allograft dysfunction were 79.57% and 80.95%, superior to 77.42% and 59.52% of BOLD. Our results showed that the non-invasive assessment of ASL in clinical kidney transplant function is a more promising imaging technique than BOLD.

The effects of thiopental on cold ischemic injury in renal transplantation

One of the most important factors influencing post-transplant success in kidney transplantation is preserving the viability of the organ from removal to transfer into the recipient. This study aimed to reduce the energy requirement with thiopental doses administered before organ transplantation, and to increase the organ viability by minimizing the tissue damage during the cold ischemia process. Twenty female Wistar albino rats were divided into two groups: control group (group C), and thiopental group (group T). In group C, a midline incision was performed, and the renal artery was isolated under ketamine and xylazine anesthesia. A standard organ storage solution (cooled to +4°C) was used for kidney perfusion. Nephrectomy was applied, and the removed kidneys were placed into +4°C standard organ storage solution and stored at +4°C for 12 hours. Animals in group T were subjected to the procedures explained above under 85mg/kg thiopental sodium anesthesia. After 12-hour storage, samples from the kidney tissues were fixed in 10% neutral buffered formalin. Histopathological evaluation and apoptosis detection via TUNEL method were performed. Tubular necrosis was more extensive in group C compared with that in group T and this difference was statistically significant. Similarly, vacuolization was widely observed in group C, and this increase was also statistically significant. For the 'dilatation of Bowman's space' parameter, a significant decrease was observed in group T compared with group C. When the apoptotic index values of both groups were examined, it was seen that they were lower in group T than those in group C. This result was statistically significant. These data suggest that thiopental provides protection to the kidney tissue during the cold storage process. Thiopental has been shown to decrease the number of apoptotic cells in the kidney tissue when administered to the donor before organ transplantation, increasing the organ viability.

Renal transplant injury at caesarean delivery: A cautionary tale and a plan for the future.

Pregnancy following renal transplantation is increasingly common. Overall pregnancy outcomes are favourable; however, specific transplant-related risks do exist. In particular, the risk of caesarean delivery is much higher in renal transplant recipients when compared to the general obstetric population. This is owing to the necessity for preterm delivery in cases of severe and early-onset pre-eclampsia and/or fetal growth restriction. We describe two recent cases of renal transplant injury at caesarean delivery at our institution, a tertiary/quaternary obstetric service, which highlight the potential operative risks associated with abdominal surgery. We propose a standardised approach in the care of transplant recipients undergoing caesarean delivery which is aimed at minimising harm and increasing patient safety.

Integrated Analysis of Prognostic Genes Associated With Ischemia-Reperfusion Injury in Renal Transplantation.

BackgroundIschemia–reperfusion injury (IRI) remains an inevitable and major challenge in renal transplantation. The current study aims to obtain deep insights into underlying mechanisms and seek prognostic genes as potential therapeutic targets for renal IRI (RIRI).MethodsAfter systematically screening the Gene Expression Omnibus (GEO) database, we collected gene expression profiles of over 1,000 specimens from 11 independent cohorts. Differentially expressed genes (DEGs) were identified by comparing allograft kidney biopsies taken before and after reperfusion in the discovery cohort and further validated in another two independent transplant cohorts. Then, graft survival analysis and immune cell analysis of DEGs were performed in another independent renal transplant cohort with long-term follow-ups to further screen out prognostic genes. Cell type and time course analyses were performed for investigating the expression pattern of prognostic genes in more dimensions utilizing a mouse RIRI model. Finally, two novel genes firstly identified in RIRI were verified in the mouse model and comprehensively analyzed to investigate potential mechanisms.ResultsTwenty DEGs upregulated in the process of RIRI throughout different donor types (living donors, cardiac and brain death donors) were successfully identified and validated. Among them, upregulation of 10 genes was associated with poor long-term allograft outcomes and exhibited strong correlations with prognostic immune cells, like macrophages. Furthermore, certain genes were found to be only differentially expressed in specific cell types and remained with high expression levels even months after RIRI in the mouse model, which processed the potential to serve as therapeutic targets. Importantly, two newly identified genes in RIRI, Btg2 and Rhob, were successfully confirmed in the mouse model and found to have strong connections with NF-κB signaling.ConclusionsWe successfully identified and validated 10 IRI-associated prognostic genes in renal transplantation across different donor types, and two novel genes with crucial roles in RIRI were recognized for the first time. Our findings offered promising potential therapeutic targets for RIRI in renal transplantation.

Assessment of chronic allograft injury in renal transplantation using diffusional kurtosis imaging

BackgroundChronic allograft injury (CAI) is a significant reason for which many grafts were lost. The study was conducted to assess the usefulness of diffusional kurtosis imaging (DKI) technology in the non-invasive assessment of CAI.MethodsBetween February 2019 and October 2019, 110 renal allograft recipients were included to analyze relevant DKI parameters. According to estimated glomerular filtration rate (eGFR) (mL/min/ 1.73 m2) level, they were divided to 3 groups: group 1, eGFR ≥ 60 (n = 10); group 2, eGFR 30–60 (n = 69); group 3, eGFR < 30 (n = 31). We performed DKI on a clinical 3T magnetic resonance imaging system. We measured the area of interest to determine the mean kurtosis (MK), mean diffusivity (MD), and apparent diffusion coefficient (ADC) of the renal cortex and medulla. We performed a Pearson correlation analysis to determine the relationship between eGFR and the DKI parameters. We used the receiver operating characteristic curve to estimate the predicted values of DKI parameters in the CAI evaluation. We randomly selected five patients from group 2 for biopsy to confirm CAI.ResultsWith the increase of creatinine, ADC, and MD of the cortex and medulla decrease, MK of the cortex and medulla gradually increase. Among the three different eGFR groups, significant differences were found in cortical and medullary MK (P = 0.039, P < 0.001, P < 0.001, respectively). Cortical and medullary ADC and MD are negatively correlated with eGFR (r = − 0.49, − 0.44, − 0.57, − 0.57, respectively; P < 0.001), while cortical and medullary MK are positively correlated with eGFR (r = 0.42, 0.38; P < 0.001). When 0.491 was set as the cutoff value, MK's CAI assessment showed 87% sensitivity and 100% specificity. All five patients randomly selected for biopsy from the second group confirmed glomerulosclerosis and tubular atrophy/interstitial fibrosis.ConclusionThe DKI technique is related to eGFR as allograft injury progresses and is expected to become a potential non-invasive method for evaluating CAI.

The significance of angiotensin II type 1 receptor (AT1 receptor) in renal transplant injury.

Humoral response beyond human leukocyte antigen (HLA) is of great interest in the transplant community. We decided to summarize the data on a new antigenic target called angiotensin II type 1 receptor (AT1 receptor). Non-HLA antibodies can now be detected in routine clinical care of patients after transplantation, but their role is not fully understood. Numerous analyses showed that non-HLA response may exert a higher risk of allograft rejection and allograft loss independently of the HLA system. Non-HLA response may even have a higher rate of antibody-mediated rejection. Information regarding antigen target, as well as the pathophysiology of its antibodies and diagnostic tools, is essential for a better understanding of non-HLA humoral response. Angiotensin II type 1 receptors are the most recognized target for non-HLA antibodies. Anti-AT1R Abs (anti-angiotensin II type 1-receptor-activating antibodies) may identify renal transplant patients at higher risk of graft rejection and loss. The presence of AT1 receptor expression analyzed together with anti-AT1R Abs should be considered for better transplant immunological risk assessment. Further assessment is required for a better understanding and to create appropriate therapeutic strategies.

Quantitative Proteomics for Monitoring Renal Transplant Injury.

This study is aimed at developing a molecular diagnostics platform to enhance the interpretation of renal allograft biopsies using quantitative proteomic profiling of formalin-fixed and paraffin-embedded (FFPE) specimens. A quantitative proteomics platform composed of 1) an optimized FFPE protein sample preparation method, 2) a tandem mass tag TMT10-plex-based proteomic workflow, and 3) a systematic statistical analysis pipeline to reveal differentially expressed proteins has been developed. This platform is then tested on a small sample set (five samples per phenotype) to reveal proteomic signatures that can differentiate T-cell mediated rejection (TCMR) and polyomavirus BK nephropathy (BKPyVN) from healthy functionally stable kidney tissue (STA). Among 2798 quantified proteins, the expression levels of 740 BKPyVN and 638 TCMR associated proteins are significantly changed compared to STA specimens. Principal component analysis demonstrated good segregation of all three phenotypes investigated. Protein detection and quantitation are highly reproducible: replicate comparative analyses demonstrated 71-84% overlap of detected proteins, and the coefficient of variation for protein measurements is <15% in triplicate liquid chromatography-tandem mass spectrometry runs. Quantitative proteomics can be applied to archived FFPE specimens to differentiate different causes of renal allograft injury.

Elucidating the molecular pathways and immune system transcriptome during ischemia-reperfusion injury in renal transplantation

Ischemia reperfusion injury (IRI) is a major challenge for renal transplantation. This study was performed to explore the mechanisms and potential molecular targets involved in renal IRI. In this study, the gene datasets GSE43974 and GSE126805 from the Gene Expression Omnibus database, which include ischemic and reperfused renal specimens, were analyzed to determine differentially expressed genes (DEGs). Gene ontology annotations, Kyoto Encyclopedia of Genes and Genomes analysis, and gene set enrichment analysis were performed to determine the pathways that are significantly enriched during ischemia and reperfusion. We also determined the microenvironment cell types xCell and performed correlation analyses to reveal the relationship between the molecular pathways and microenvironment cell infiltration. We found 77 DEGs (76 up- and 1 downregulated) and 323 DEGs (312 up- and 11 downregulated) in the GSE43974 and GSE126805 datasets, respectively. Similar signaling pathway enrichment patterns were observed between the two datasets. The combined analyses demonstrate that the NOD-like receptor signaling pathway and its two downstream signaling pathways, MAPK and NF-kβ, are the major significantly enriched pathways. The xCell analysis identified immune cells that are significantly changed after reperfusion, including hematopoietic stem cells, M2 macrophages, monocytes, Treg cells, conventional dendritic cells, and pro B-cells. Enrichment scores of the NOD-like receptor signaling pathway and its downstream pathways during IRI was significantly correlated with the change levels in class-switched memory B-cell and hematopoietic stem cells in both datasets. These data reveal the important role of the NOD-like receptor signaling pathway during IRI, and the close relationship between this pathway and infiltration of specific immune cell types. Our data provide compelling insights into the pathogenesis and potential therapeutic targets for renal IRI.

Effect of ozone oxidative preconditioning on oxidative stress injury in a rat model of kidney transplantation.

The aim of the present study was to investigate the protective effect of ozone oxidative preconditioning (OOP) on renal oxidative stress injury in a rat model of kidney transplantation. Thirty-six male Sprague Dawley (SD) rats were randomly divided into three groups: A sham (S) group, a kidney transplantation (KT) group and an OOP and kidney transplantation (OOP+KT) group. In the S group, the rats' abdomens were opened and closed without transplantation. In the KT group, the rats received a left kidney from donor SD rats. In the OOP+KT group, donor SD rats received 15 OOP treatments by transrectal insufflations (1 mg/kg), once a day, at an ozone concentration of 50 µg/ml, before the kidney transplantation. Twenty-four hours after transplantation, the parameters of renal function of the recipients were measured. The morphology and pathological effects of renal allograft were examined using hematoxylin and eosin staining, periodic acid-Schiff staining, a terminal deoxynucleotidyl transferase dUTP nick end labeling assay and immunohistochemistry. Markers of oxidative stress were also detected using the thiobarbituric acid method, and expression levels of Nrf-2 and HO-1 were determined by western blot analysis. Blood urea nitrogen and creatinine levels were significantly decreased in the OOP+KT group compared with the KT group, and the morphology and pathological changes of renal allograft were also less severe. Meanwhile, the renal allograft cell apoptosis index was significantly higher in the KT group compared to the OOP+KT group (P<0.05). Levels of superoxide dismutase, glutathione and catalase in the renal allografts were significantly higher in the OOP+KT group compared to those in the KT group (P<0.05), while malondialdehyde levels were significantly lower in the OOP+KT group compared to those in the KT group (P<0.05). Western blot analysis indicated that the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf-2) and heme oxygenase 1 (HO-1) were significantly higher in the OOP+KT compared to the KT group (P<0.05). In conclusion, the mechanism by which OOP alleviates oxidative stress injury in renal transplantation may be related to the activation of the signaling pathways of Nrf-2/HO-1 and inhibition of renal tubular epithelial cell apoptosis.

The Use of Genomics and Pathway Analysis in Our Understanding and Prediction of Clinical Renal Transplant Injury.

The development and application of high-throughput molecular profiling have transformed the study of human diseases. The problem of handling large, complex data sets has been facilitated by advances in complex computational analysis. In this review, the recent literature regarding the application of transcriptional genomic information to renal transplantation, with specific reference to acute rejection, acute kidney injury in allografts, chronic allograft injury, and tolerance is discussed, as is the current published data regarding other "omics" strategies-proteomics, metabolomics, and the microRNA transcriptome. These data have shed new light on our understanding of the pathogenesis of specific disease conditions after renal transplantation, but their utility as a biomarker of disease has been hampered by study design and sample size. This review aims to highlight the opportunities and obstacles that exist with genomics and other related technologies to better understand and predict renal allograft outcome.

Mining the human urine proteome for monitoring renal transplant injury

The human urinary proteome provides an assessment of kidney injury with specific biomarkers for different kidney injury phenotypes. In an effort to fully map and decipher changes in the urine proteome and peptidome after kidney transplantation, renal allograft biopsy matched urine samples were collected from 396 kidney transplant recipients. Centralized and blinded histology data from paired graft biopsies was used to classify urine samples into diagnostic categories of acute rejection, chronic allograft nephropathy, BK virus nephritis, and stable graft. A total of 245 urine samples were analyzed by liquid chromatography-mass spectrometry using isobaric Tags for Relative and Absolute Quantitation (iTRAQ) reagents. From a group of over 900 proteins identified in transplant injury, a set of 131 peptides were assessed by selected reaction monitoring for their significance in accurately segregating organ injury causation and pathology in an independent cohort of 151 urine samples. Ultimately, a minimal set of 35 proteins were identified for their ability to segregate the 3 major transplant injury clinical groups, comprising the final panel of 11 urinary peptides for acute rejection (93% area under the curve [AUC]), 12 urinary peptides for chronic allograft nephropathy (99% AUC), and 12 urinary peptides for BK virus nephritis (83% AUC). Thus, urinary proteome discovery and targeted validation can identify urine protein panels for rapid and noninvasive differentiation of different causes of kidney transplant injury, without the requirement of an invasive biopsy.

Induction of IL-8(CXCL8) and MCP-1(CCL2) with oxidative stress and its inhibition with N-acetyl cysteine (NAC) in cell culture model using HK-2 cell

Renal transplantation can often be complicated due to delayed graft function, which is a direct sequel of ischaemia reperfusion injury. The adverse outcome of delayed graft function is not only short term but the long-term function of the graft is also affected. Therefore, it is important to understand the mechanisms of ischaemia reperfusion injury. Reactive oxygen species are the key mediators in ischaemia reperfusion injury causing direct cell damage which also initiate inflammation by inducing chemokines. The presence of inflammation is a marker of severe delayed graft function. However, the effect of oxidative stress on the expression of key chemokines has not been fully established yet.Therefore, the aim of this study was to measure the oxidative stress response and the secretion of chemokines in a cell culture model that mimics the effects of ischaemia reperfusion injury in immortalised human renal proximal tubular epithelial cells, HK-2.Cells were treated with varying concentrations of hydrogen peroxide and markers of oxidative stress response and chemokine release were measured. Exposure to hydrogen peroxide induced a significant increase in the activity of the antioxidant enzyme glutathione peroxidase and the levels of the chemokines Interleukin-8 (IL-8; CXCL8) and MCP-1 (CCL2). A dose related increase of chemokine secretion was also observed. The cytokine Interleukin-1β (IL-1β) at 1ng/ml significantly potentiated the expression of both IL-8 (CXCL8) and MCP-1 (CCL2) which showed synergistic response in the presence of hydrogen peroxide. Pre-incubation of the cells with the anti-oxidant N-acetyl cysteine (NAC) strongly suppressed the induction of both IL-8 and MCP-1 when stimulated with hydrogen peroxide and IL-1β.This study demonstrates the potential of anti-oxidants like N-acetyl cysteine in ameliorating the effects of ischaemia reperfusion injury thus suggesting a new therapeutic approach in renal transplantation. These findings can have potential implications for clinical use to prevent ischaemia reperfusion injury in renal transplantation.

Matrix Metalloproteinase-9 and Graft Preservation Injury in Clinical Renal Transplantation

BackgroundDeleterious effects of matrix metalloproteinase-9 (MMP-9) have been established in experimental renal ischemia-reperfusion models but not in clinical renal transplantation thus far. MethodsWe studied MMP-9 and its physiological inhibitor tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) in 45 consecutive patients of a larger trial in renal transplantation: perioperative anti-thymocyte globulin (group A, n = 15), perioperative basiliximab (group B, n = 16), and conventional triple therapy (group C, n = 14). In addition to systemic blood samples, local blood samples were obtained simultaneously at 1 and 5 minutes after reperfusion from iliac artery and graft vein for calculation of transrenal changes. Because anti-thymocyte globulin activates inflammation, group A was analyzed separately. Groups B and C were pooled (group BC). ResultsAnti-thymocyte globulin infusion caused a robust rise of MMP-9 in the systemic circulation in group A. No significant transrenal difference of MMP-9 or TIMP-1 occurred in either group during graft reperfusion. In group BC, strong transrenal release of MMP-9 at 1 minute after reperfusion correlated with cold ischemia time (R = 0.66, P = .0001) and was associated with delayed graft function (P = .052). ConclusionsRenal production of MMP-9 on graft reperfusion is associated with cold ischemia time and emergence of delayed graft function. MMP inhibition may offer a means to reduce reperfusion injury in renal transplantation.

B cells regulate antidonor T-cell reactivity in transplantation

The analyses of indirect T cell responses in patients with antibody-mediated renal transplant injury by Shiu et al. emphasize the complex contribution of B cells in alloimmunity. The data suggest at least three distinct but potentially overlapping consequences of T/B cell interactions: antigen presentation by B cells, alloantibody production, and immune regulation. These multifaceted functions of B cells should be taken into consideration while developing diagnostic tools and therapeutic strategies.

Hydrogen sulphide as a novel therapy to ameliorate cyclosporine nephrotoxicity

BackgroundCalcineurin inhibitors have significant nephrotoxic side effects, which can exacerbate ischemia–reperfusion injury in renal transplantation. Novel therapeutic agents such as hydrogen sulphide (H2S) may reduce these harmful effects. This study investigated the effects of H2S on cyclosporine (CsA) induced nephrotoxicity. Materials and methodsPorcine kidneys were subjected to 15 min of warm ischemia and 2 h of static cold storage. They were reperfused for 3 h with oxygenated normothermic autologous whole blood on an isolated organ reperfusion apparatus. Kidneys were treated with CsA during reperfusion (n = 6) or cyclosporine and 0.25 mmol/L of H2S infused 10 min before and 20 min after reperfusion (n = 6). These were compared with untreated controls (n = 7). ResultsCsA caused a significant reduction in renal blood flow during reperfusion, which was reversed by H2S (area under the curve renal blood flow CsA 257 ± 93 versus control 477 ± 206 versus CsA + H2S 478 ± 271 mL/min/100 g.h; P = 0.024). Urine output was higher after 2 h of reperfusion in the CsA + H2S group (CsA + H2S 305 ± 218 versus CsA 78 ± 180 versus control 210 ± 45 mL; P = 0.034). CsA treatment was associated with an increase in tubular injury, which was not reversed by H2S (area under the curve fractional excretion of sodium, control 77 ± 53 versus CsA 100 ± 61 versus CsA + H2S 111 ± 57%.h; P = 0.003). Histologic evaluation showed significant vacuolation and glomerular shrinkage in the CsA group. These were significantly reduced by H2S (P = 0.005, 0.002). ConclusionsH2S reversed the vasoconstriction changes associated with CsA treatment during reperfusion.

Ischemia and reperfusion injury in renal transplantation: hemodynamic and immunological paradigms.

Ischemia and reperfusion injury is an inevitable event in renal transplantation. The most important consequences are delayed graft function, longer length of stay, higher hospital costs, high risk of acute rejection, and negative impact of long-term follow-up. Currently, many factors are involved in their pathophysiology and could be classified into two different paradigms for education purposes: hemodynamic and immune. The hemodynamic paradigm is described as the reduction of oxygen delivery due to blood flow interruption, involving many hormone systems, and oxygen-free radicals produced after reperfusion. The immune paradigm has been recently described and involves immune system cells, especially T cells, with a central role in this injury. According to these concepts, new strategies to prevent ischemia and reperfusion injury have been studied, particularly the more physiological forms of storing the kidney, such as the pump machine and the use of antilymphocyte antibody therapy before reperfusion. Pump machine perfusion reduces delayed graft function prevalence and length of stay at hospital, and increases long-term graft survival. The use of antilymphocyte antibody therapy before reperfusion, such as Thymoglobulin™, can reduce the prevalence of delayed graft function and chronic graft dysfunction.

Noninvasive monitoring of mouse renal allograft rejection using micro-CT.

PurposeAcute renal graft rejection can only be definitively diagnosed by renal biopsy. However, biopsies carry a risk of renal transplant injury and loss. Micro-CT is widely used in preclinical studies of small animals. Here, we propose micro-CT could noninvasively monitor and evaluate renal location and function in a mouse kidney transplant model.MethodsOrthotopic kidney transplantation was performed in a BALB/c -to- C57BL/6j or C57BL/6j-to- C57BL/6j mouse model. After optimizing imaging techniques, five mice were imaged with micro-CT and the findings were verified histologically.ResultsMicro-CT can monitor and evaluate renal location and function after orthotopic kidney transplantation. There were no mice deaths while renal transplants were failure.ConclusionWe propose that graft micro-CT imaging is a new option that is noninvasive and specific, and can aid in early detection and follow-up of acute renal rejection. This method is potentially useful to improve posttransplant rejection monitoring.

Possible Mechanisms and Potential Urine Protein Biomarkers through Quantitative Proteomics and Bioinformatics.

Introduction: Inability to effectively monitor graft injuries leads to graft dysfunction. A non-invasive tool to monitor such injuries is an unmet need. Method: Through a robust and comprehensive proteomics analysis, rigorous bioinformatics, and ELISA on a set of 480 urine samples with matched biopsies, we identified and validated potential biomarkers for acute rejection (AR), chronic allograft injury (CAI), and BK virus nephropathy (BKVN). Result: A panel of 100 statistically significant proteins as potential biomarkers for different transplant injury is identified. Four proteins, FGB, FGG, SUMO2, and HLA-DRB1 were selected based on their relevance in AR. Urinary FBB in AR was significantly higher vs STA (p=0.04), vs CAI (p=0.05), and vs BKV (p=0.03). The increased urine protein level of FBG in AR (p=0.04), vs CAI (p=0.05), and vs BKV (p=0.02). The urine protein level of HLA-DRB1 was significantly higher in AR vs STA (p=0.001), vs CAI (p=0.003), and vs BKV (p=0.04). Urine SUMO2 level was significantly higher in AR vs STA urine (p=0.005), and vs BKVN urine (p=0.04). An ROC analysis to identify AR from the rest of the phenotypes (CAI, BK, and STA) on the data from FBB, FGG, and HLA-DRB1 yielded an AUC of 0.8.Table: No Caption available.Figure: No Caption available.Conclusion: A panel of 3 urinary proteins, mined by high throughput proteomics, and validated by customized ELISA, allows for non-invasive diagnosis of AR, not confounded by BKVN. This urinary assay requires no local sample processing, is robust and can be used as a sensitive assay for out-patient renal transplant injury surveillance.

The influence of non-HLA antibodies directed against angiotensin II type 1 receptor (AT1R) on early renal transplant outcomes.

Non-HLA antibodies (Abs) targeting vascular receptors are thought to have an impact on renal transplant injury. Anti-angiotensin II type 1-receptor-activating antibodies (anti-AT1R) have been mentioned to stimulate a severe vascular rejection, but the pretransplant screening has not been introduced yet. The aim of our study was to assess the incidence and importance of anti-AT1R antibodies and their influence on renal transplant in the 1st year of observation. We prospectively evaluated the presence of anti-AT1R antibodies in 117 consecutive renal transplant recipients in pre- and post-transplant screening. Anti-AT1R antibodies were observed in 27/117 (23%) of the analyzed recipients already before transplantation. The function of renal transplant was considerably worse in anti-AT1R(+) group. The patients with anti-AT1R Abs >9U/ml lost their graft more often. Biopsy-proven AR was described in 4/27 (15%) pts in the anti-AT1R(+) group and 13/90 (14.4%) in the anti-AT1R(-) group, but more severe cases of Banff IIB or antibody-mediated rejection (AMR) were more often observed in anti-AT1R (+) 4/27 (15%) vs. 1/90 (1.1%) in anti-AT1R(+) (P=0.009). Patients with anti-AT1R Abs level >9U/ml run a higher risk of graft failure independently of classical immunological risk factors. The recipients with anti-AT1R Abs developed more severe acute rejections described as IIB or AMR in Banff classification. More recipients among the anti-AT1R-positive ones lost the graft. Our study suggests monitoring of anti-AT1R Abs before renal transplantation for assessment of immunologic risk profiles and the identification of patients highly susceptible to immunologic events, graft failure, and graft loss.

The impact of non-HLA antibodies directed against endothelin-1 type A receptors (ETAR) on early renal transplant outcomes

BackgroundNon-HLA antibodies (Abs) targeting vascular receptors are considered to have an influence on renal transplant injury. Anti-endothelin-1 type A receptor (anti-ETAR) antibodies were associated with cellular and antibody-mediated rejection and early onset of vasculopathy in heart transplant patients but their role in renal transplantation remains unclear. The aim of our study was to assess the incidence and importance of anti-ETAR antibodies and their impact on renal transplant during the first year observation. MethodsWe evaluated the presence of anti-ETAR antibodies in 116 consecutive renal transplant recipients in pre- and post-transplant screening (before and in 1st, 3rd, 6th, 12th month after transplantation). Additionally, we assessed the presence of anti-HLA antibodies. Anti-ETAR antibodies were assayed by ELISA. The diagnosis of acute rejection was based on the Banff criteria. ResultsAnti-ETAR antibodies were observed in 55 (47.4%) of the analyzed recipients before transplantation. The function of renal transplant was significantly worse in the anti-ETAR(+) group compared to the anti-ETAR(−) group during the first post-transplant year. One month after transplantation the serum creatinine in anti-ETAR (+) patients (pts) was 1.86±0.8mg/dl and 1.51±0.5 in anti-ETAR(−) pts (p=0.009). Twelve months after transplantation the difference between the groups was still observed 1.70±0.7 vs. 1.40±0.4 (p=0.04).Biopsy proven acute rejection was recognized in 8/55 (14.5%) in ETAR(+) and 9/61 (14.8%) in ETAR(−) patients but cases with mild to severe intimal arteritis (v1–v3) were more often observed in patients with the presence of anti-ETAR Abs 4/55 (7.2%) comparing with 1/61 (1.6%) in anti-ETAR(−) patients. The anti-ETAR antibody levels varied at different measurement intervals during the one-year follow-up. ConclusionsThe presence of anti-ETAR antibodies is associated with a worse renal transplant function during the first 12months after transplantation. Including anti-ETAR antibodies in the diagnostics of renal transplant recipient immune status should be considered to provide comprehensive assessment of humoral alloimmunity.