Long-term renal outcomes after delayed graft function

The effect of goal-directed fluid therapy on delayed graft function in kidney transplant recipients: A systematic review and meta-analysis

Delayed graft function (DGF) is a common post-operative complication with potential long-term sequelae for many kidney transplant recipients, and hemodynamic factors and fluid status play a role. Fixed perioperative fluid infusions are the standard of care, but more recent evidence in the non-transplant population has suggested benefit with goal-directed fluid strategies based on hemodynamic targets. We searched MEDLINE, EMBASE, Cochrane Controlled Trials Registry and Google Scholar through December 2022 for randomized controlled trials comparing risk of DGF between goal-directed and conventional fluid therapy in adults receiving a living or deceased donor kidney transplant. Effect estimates were reported with odds ratios (OR) and pooled using random effects meta-analysis. We identified 4 studies (205 participants) that met the inclusion criteria. The use of goal-directed fluid therapy had no significant effect on DGF (OR 1.37 95% CI, 0.34-5.6; p = 0.52; I2 = 0.11). Subgroup analysis examining effects among deceased and living kidney donation did not reveal significant differences in the effects of fluid strategy on DGF between subgroups. Overall, the strength of the evidence for goal-directed versus conventional fluid therapy to reduce DGF was of low certainty. Our findings highlight the need for larger trials to determine the effect of goal-directed fluid therapy on this patient-centered outcome.

Delayed Graft Function in Kidney Transplant: Risk Factors, Consequences and Prevention Strategies

Background. Delayed graft function is a frequent complication of kidney transplantation that requires dialysis in the first week posttransplant. Materials and Methods. We searched for the most relevant articles in the National Institutes of Health library of medicine, as well as in transplantation, pharmacologic, and nephrological journals. Results. The main factors that may influence the development of delayed graft function (DGF) are ischemia–reperfusion injury, the source and the quality of the donated kidney, and the clinical management of the recipient. The pathophysiology of ischemia–reperfusion injury is complex and involves kidney hypoxia related to the duration of warm and cold ischemia, as well as the harmful effects of blood reperfusion on tubular epithelial cells and endothelial cells. Ischemia–reperfusion injury is more frequent and severe in kidneys from deceased donors than in those from living donors. Of great importance is the quality and function of the donated kidney. Kidneys from living donors and those with normal function can provide better results. In the peri-operative management of the recipient, great attention should be paid to hemodynamic stability and blood pressure; nephrotoxic medicaments should be avoided. Over time, patients with DGF may present lower graft function and survival compared to transplant recipients without DGF. Maladaptation repair, mitochondrial dysfunction, and acute rejection may explain the worse long-term outcome in patients with DGF. Many different strategies meant to prevent DGF have been evaluated, but only prolonged perfusion of dopamine and hypothermic machine perfusion have proven to be of some benefit. Whenever possible, a preemptive transplant from living donor should be preferred.

In kidney recipients from the same deceased donor, discordance in delayed graft function is associated with the worst outcomes

Delayed graft function(DGF) is a common complication among deceased donor kidney transplant recipients(DDKTs) and is associated with worse outcomes. The effect on outcomes of concordance versus discordance in DGF between two different recipients of kidneys from the same donor is largely unknown. We reviewed all adult DDKTs for which both kidneys were transplanted to two different recipients at our center between 2014-2019. DDKTs were divided into four groups based on the DGF status: concordance no DGF(cc-no-DGF); discordance no DGF(dd-no-DGF); discordance DGF(dd-DGF) and concordance in DGF(cc-DGF). Acute rejection (AR) and death censored graft failure (DCGF) were outcomes of interest. A total of 578 DDKTs fulfilled our selection criteria, 280 were in cc-no-DGF, 83 in dd-no-DGF, 83 in dd-DGF, and 132 in cc-DGF. Compared to cc-no-DGF, in univariate analysis, dd-DGF was associated with an increased risk of AR(HR:1.60; 95% CI:1.0-2.56) but cc-DGF was not(HR:1.01; 95% CI:0.63-1.62). dd-DGF was not associated with an increased risk of AR in multivariate analysis. In multivariate analysis, dd-DGF was associated with an increased risk of DCGF (HR: 2.70; 95% CI: 1.05-6.93) but cc-DGF was not (HR:2.36; 95% CI:0.97-5.70). Discordance in DGF is associated with worse outcomes and may need close follow-up and monitoring to improve the outcomes. This article is protected by copyright. All rights reserved.

Biomarkers as diagnostic tests for delayed graft function in kidney transplantation

Delayed graft function (DGF) after kidney transplantation is associated with inferior outcomes and higher healthcare costs. DGF is currently defined as the requirement for dialysis within seven days post-transplant; however, this definition is subjective and nonspecific. Novel biomarkers have potential to improve objectivity and enable earlier diagnosis of DGF. We reviewed the literature to describe the range of novel biomarkers previously studied to predict DGF. We identified marked heterogeneity and low reporting quality of published studies. Among the novel biomarkers, serum NGAL had the greatest potential as a biomarker to predict DGF, but requires further assessment and validation through larger scale studies of diagnostic test performance. Given inadequacies in the dialysis-based definition, coupled with the high incidence and impact of DGF, such studies should be pursued.

Intraoperative fluid management and kidney transplantation outcomes: A retrospective cohort study

BACKGROUND

Patients undergoing kidney transplantation traditionally receive liberal amounts of fluid during surgery. However, excessive fluids can lead to fluid overload and ileus. In this retrospective cohort study, we compared the effect of restrictive versus liberal fluid therapy on kidney transplantation outcomes.

METHODS

Patients who underwent deceased-donor kidney transplantation at Mayo Clinic from January 2014 to March 2019 were included. Those who received <3 L of intravenous fluids intraoperatively were categorized as "restrictive;" those who received ≥3 L were categorized as "liberal." The primary outcome was incidence of delayed graft function (DGF). Secondary outcomes included length of stay, readmission within 30 days, time to return of bowel function, and incidence of postoperative complications.

RESULTS

Of the 1171 patients included, 557 were in the restrictive group and 614 in the liberal group. The mean (SD) fluid intake was 2.17 (.54) L in the restrictive group and 3.67 (.68) L in the liberal group (P<.001). There was no difference in DGF (relative risk, 1.03; P = .56), length of stay (P = .34), readmission (P = .80), return of bowel function (P = .71), or other postoperative complications.

CONCLUSIONS

Intraoperative restrictive fluid therapy during kidney transplantation was not associated with DGF or worse outcomes when compared with liberal fluid therapy.

A pilot study evaluating GSK1070806 inhibition of interleukin-18 in renal transplant delayed graft function

INTRODUCTION

Delayed graft function (DGF) following renal transplantation is a manifestation of acute kidney injury (AKI) leading to poor long-term outcome. Current treatments have limited effectiveness in preventing DGF. Interleukin-18 (IL18), a biomarker of AKI, induces interferon-γ expression and immune activation. GSK1070806, an anti-IL18 monoclonal antibody, neutralizes activated (mature) IL18 released from damaged cells following inflammasome activation. This phase IIa, single-arm trial assessed the effect of a single dose of GSK1070806 on DGF occurrence post donation after circulatory death (DCD) kidney transplantation.

METHODS

The 3 mg/kg intravenous dose was selected based on prior studies and physiologically based pharmacokinetic (PBPK) modeling, indicating the high likelihood of a rapid and high level of IL18 target engagement when administered prior to kidney allograft reperfusion. Utilization of a Bayesian sequential design with a background standard-of-care DGF rate of 50% based on literature, and confirmed via extensive registry data analyses, enabled a statistical efficacy assessment with a minimal sample size. The primary endpoint was DGF frequency, defined as dialysis requirement ≤7 days post transplantation (except for hyperkalemia). Secondary endpoints included safety, pharmacokinetics and pharmacodynamic biomarkers.

RESULTS

GSK1070806 administration was associated with IL18-GSK1070806 complex detection and increased total serum IL18 levels due to IL18 half-life prolongation induced by GSK1070806 binding. Interferon-γ-induced chemokine levels declined or remained unchanged in most patients. Although the study was concluded prior to the Bayesian-defined stopping point, 4/7 enrolled patients (57%) had DGF, exceeding the 50% standard-of-care rate, and an additional two patients, although not reaching the protocol-defined DGF definition, demonstrated poor graft function. Six of seven patients experienced serious adverse events (SAEs), including two treatment-related SAEs.

CONCLUSION

Overall, using a Bayesian design and extensive PBPK dose modeling with only a small sample size, it was deemed unlikely that GSK1070806 would be efficacious in preventing DGF in the enrolled DCD transplant population.

TRIAL REGISTRATION

NCT02723786.

Quantitative Assessment of Intraoperative Laser Fluorescence Angiography with Indocyanine Green Predicts Early Graft Function after Kidney Transplantation

Objective:

This study was designed to demonstrate the predictive ability of quantitative indocyanine green (ICG) fluorescence angiography for the short-term postoperative outcome, the occurrence of delayed graft function (DGF), and long-term graft survival.

Summary Background Data:

DGF is a relevant problem after kidney transplantation; sufficient microperfusion of the allograft is crucial for postoperative organ function. Fluorescence angiography with ICG can serve as an intraoperative quality control of microperfusion.

Methods:

This prospective diagnostic study, conducted in 2 German transplantation centers from November 2015 to October 2018, included 128 consecutive kidney transplantations. Intraoperative assessment of the allograft microperfusion was performed by near-infrared fluorescence angiography with ICG; a software was used for quantitative analysis. The associations between perfusion parameters (eg, ICG Ingress) and donor, recipient, peri-procedural, and postoperative characteristics were evaluated.

Results:

DGF occurred in 23 (24%) kidney recipients from deceased donors. ICG Ingress (P = 0.0027), donor age (P = 0.0452), recipient age (P = 0.0139), and recipient body mass index (P = 0.0017) were associated with DGF. ICG Ingress correlated significantly with recipient age (r = −0.27662, P = 0.0016), cold and warm ischemia time (r = −0.25204, P = 0.0082; r = −0.19778, P = 0.0283), operating time (r = −0.32208, P = 0.0002), eGFR on postoperative days 1 (r =+0.22674, P = 0.0104) and 7 (r = +0.33189, P = 0.0001). The cutoff value for ICG Ingress was 106.23 AU with sensitivity of 78.3% and specificity of 80.8% (P < 0.0001) for the prediction of DGF.

Conclusion:

Fluorescence angiography with ICG allows intraoperative quantitative assessment of microperfusion during kidney transplantation. The parameter ICG Ingress reflects recipient and procedure characteristics and is able to predict the incidence of DGF.

Trial registration:

Clinicaltrials.gov: NCT-02775838

Pericardectomy after pericarditis constrictiva led to onset of transplant kidney function after 98 days of anuric kidney graft: a case report

BACKGROUND

Constrictive pericarditis is easily overlooked and can lead to severe problems in hemodynamics and end-organ perfusion, in our patient leading to 98 days of anuria after living kidney transplantation. This was completely reversible after pericardectomy.

CASE PRESENTATION

A 43-year-old female caucasian patient received a living kidney donation from her mother. She had developed end-stage renal disease 2 years prior due to nephrotic syndrome linked to graft-versus-host disease after allogenic stem-cell transplantation for aplastic anemia. The graft showed insufficient function already in the early postoperative phase. Dialysis was paused after surgery, but the patient developed hypervolemia with ascites and edema in the lower extremities. Doppler ultrasonography showed scarce perfusion, with intrarenal arterial waveforms without end-diastolic flow. The venous perfusion profiles showed pulsatile retrograde flow. There was no identifiable reason for a primary vascular perfusion problem on ultrasonography or transplant kidney angiography. Kidney transplant biopsy revealed no rejection but extensive acute tubular necrosis. Three weeks after transplantation, the patient developed an acute anuric graft failure caused by severe cardiac decompensation. Echocardiography revealed a previously unnoticed constrictive pericarditis, which could be confirmed in a cardio computed tomography scan. The constrictive pericarditis had not been apparent on previous x-rays, computed tomography scans, or echocardiographies, including those for transplantation evaluation. Conservative management of the constrictive pericarditis was not successful and the graft remained anuric. Eventually, the patient underwent pericardectomy 16 weeks after kidney transplantation. Shortly after surgery, the graft started urine production again, which significantly increased within a few days. The clearance improved and 2 weeks later, the patient was free from dialysis.

CONCLUSIONS

This case illustrates that special attention should be given to the pericardium during transplant evaluation, especially for patients who previously underwent stem-cell transplantations, chemotherapy or radiation.

Financial impact of delayed graft function in kidney transplantation

Increased utilization of suboptimal organs in response to organ shortage has resulted in increased incidence of delayed graft function (DGF) after transplantation. Although presumed increased costs associated with DGF are a deterrent to the utilization of these organs, the financial burden of DGF has not been established. We used the Premier Healthcare Database to conduct a retrospective analysis of healthcare resource utilization and costs in kidney transplant patients (n = 12 097) between 1/1/2014 and 12/31/2018. We compared cost and hospital resource utilization for transplants in high-volume (n = 8715) vs low-volume hospitals (n = 3382), DGF (n = 3087) vs non-DGF (n = 9010), and recipients receiving 1 dialysis (n = 1485) vs multiple dialysis (n = 1602). High-volume hospitals costs were lower than low-volume hospitals ($103 946 vs $123 571, P < .0001). DGF was associated with approximately $18 000 (10%) increase in mean costs ($130 492 vs $112 598, P < .0001), 6 additional days of hospitalization (14.7 vs 8.7, P < .0001), and 2 additional ICU days (4.3 vs 2.1, P < .0001). Multiple dialysis sessions were associated with an additional $10 000 compared to those with only 1. In conclusion, DGF is associated with increased costs and length of stay for index kidney transplant hospitalizations and payment schemes taking this into account may reduce clinicians' reluctance to utilize less-than-ideal kidneys.

Factors predicting kidney delayed graft function among recipients of simultaneous liver-kidney transplantation: A single-center experience

BACKGROUND

Kidney delayed graft function (kDGF) remains a challenging problem following simultaneous liver and kidney transplantation (SLKT) with a reported incidence up to 40%. Given the scarcity of renal allografts, it is crucial to minimize the development of kDGF among SLKT recipients to improve patient and graft outcomes. We sought to assess the role of preoperative recipient and donor/graft factors on developing kDGF among recipients of SLKT.

METHODS

A retrospective review of 194 patients who received SLKT in the period from January 2004 to March 2017 in a single center was performed to assess the effect of preoperative factors on the development of kDGF.

RESULTS

Kidney delayed graft function was observed in 95 patients (49%). Multivariate analysis revealed that donor history of hypertension, cold static preservation of kidney grafts [versus using hypothermic pulsatile machine perfusion (HPMP)], donor final creatinine, physiologic MELD, and duration of delay of kidney transplantation after liver transplantation were significant independent predictors for kDGF. kDGF is associated with worse graft function and patient and graft survival.

CONCLUSIONS

Kidney delayed graft function has detrimental effects on graft function and graft survival. Understanding the risks and combining careful perioperative patient management, proper recipient selection and donor matching, and graft preservation using HPMP would decrease kDGF among SLKT recipients.

Influence of Pretransplant Dialysis Vintage on Repeated Kidney Transplantation Outcomes

Dialysis has a dose-dependent effect on first kidney transplantation outcomes, and a shorter waiting time on dialysis is associated with superior graft function. There are not enough data to support this statement in the case of a repeated transplantation. As such, we aimed to evaluate the influence of the dialysis vintage before the last transplantation on graft function as well as patient and graft survival in repeated transplantation situations. Patients who underwent repeated kidney transplantations were included in the retrospective study. Specifically, 79 patients were included who were divided into 4 groups according to the dialysis vintage before the last transplantation. We assessed graft function and patient and graft survival rates after 1- and 3-year follow-up. One-year graft function was worse for patients with a dialysis vintage of more than 31 months (P = .005), but there was no difference after 3 years. One- and 3-year graft survival was better for patients with a dialysis vintage of less than 12 months (P = .017). We concluded that a longer waiting time on dialysis was associated with worse graft function and diminished long-term graft survival after repeated kidney transplantation.

Effects of cyclosporine A pretreatment of deceased organ donors on kidney graft function (Cis-A-rein): study protocol for a randomized controlled trial

BACKGROUND

Renal transplantation represents the treatment of choice of end-stage kidney disease. Delayed graft function (DGF) remains the most frequent complication after this procedure, reaching more than 30%. Its prevention is essential as it impedes early- and long-term prognosis of transplantation. Numerous pharmacological interventions aiming to prevent ischemia-reperfusion injuries failed to reduce the rate of DGF. We hypothesize that cyclosporine as an early preconditioning procedure in donors would be associated with decreased DGF.

METHODS

The Cis-A-rein study is an investigator-initiated, prospective, multicenter, double-blind, randomized, controlled study performed to assess the effects of a donor preconditioning with cyclosporine A on kidney grafts function in transplanted patients. After randomization, a brain dead donor will receive 2.5 mg kg^-1 of cyclosporine A or the same volume of 5% glucose solution. The primary objective is to compare the rate of DGF, defined as the need for at least one dialysis session within the 7 days following transplantation, between both groups. The secondary objectives include rate of slow graft function, mild and severe DGF, urine output and serum creatinine during the first week after transplantation, rate of primary graft dysfunction, renal function and mortality at 1 year. The sample size (n = 648) was determined to obtain 80% power to detect a 10% difference for rate of DGF at day 7 between the two groups (30% of the patients in the placebo group and 20% of the patients in the intervention group).

DISCUSSION

Delayed graft function is a major issue after renal transplantation, impeding long-term prognosis. Cyclosporine A pretreatment in deceased donors could improve the outcome of patients after renal transplantation.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT02907554 Registered on 20 September 2016.

Delayed Initiation of Tacrolimus Is Safe and Effective in Renal Transplant Recipients With Delayed and Slow Graft Function

BACKGROUND

Tacrolimus is widely used in renal transplantation to help prevent acute and chronic rejection, but the nephrotoxicity of tacrolimus may compromise renal function. This study investigates the safety and efficacy in delayed initiation of tacrolimus after antilymphocyte induction therapy in kidney transplant recipients.

METHODS

This retrospective cohort analysis involved data from 68 kidney transplant recipients receiving standard induction therapy (basiliximab [Simulect] or thymoglobulin) combined with tacrolimus. The patients were divided into 2 groups according to whether the start time of tacrolimus therapy was before or after 24 hours posttransplantation. Acute rejection, common complications of immunosuppression, and graft survival were compared.

RESULTS

The mean (SD) timing of tacrolimus administered in the Delayed group was 4 (1.9) days after transplantation. The Delayed group patients had a higher percentage of slow graft function and delayed graft function than the No-delay group. Compared with the No-delay group, delayed initiation of tacrolimus did not increase risk of biopsy-proven acute rejection, infection, posttransplant diabetes mellitus, graft survival, and patient survival.

CONCLUSIONS

Our study confirmed delayed initiation of tacrolimus after antilymphocyte induction therapy is safe and effective in renal transplant recipients with slow or delayed graft function.

Association of Brain-Dead Donors' Terminal Inflammation With Delayed Graft Function in Kidney Transplant Recipients

BACKGROUND

Systemic inflammation affects kidney function in a wide range of diseases. Even in kidney transplant recipients, higher levels of C-reactive protein (CRP) are invariably associated with both worse short- and long-term graft outcomes. However, little is known about systemic inflammation in kidney donors and, notably, brain death causes a strong systemic inflammatory response.

OBJECTIVE

To analyze the role of systemic inflammation of brain-dead donors on short-term kidney graft outcomes (ie, delayed graft function [DGF], defined as the need of dialysis during the first week after transplantation).

MATERIALS AND METHODS

Retrospective analysis of clinical and biochemical characteristics of all brain-dead kidney donors generated in the Hospital Clínic of Barcelona in the 2006 to 2015 period (n = 194). Donors who were tested for CRP in the 24 hours before BD declaration were included (n = 97, 50% of initial population). Clinical and biochemical features of their respective recipients (n = 165) were analyzed, comparing recipients who developed DGF (n = 30) with recipients who did not (n = 135).

RESULTS

Donors whose recipients later developed DGF had much higher CRP values (10.58 [5.1-18.21] vs 4.81 [1.42-12.2] mg/dL, P = .025). Other characteristics associated with the development of DGF were renal biopsy score and recipient dialysis vintage (P = .025 and P = .002, respectively). In logistic regression analysis, PCR maintained significance in the non-expanded criteria donor (ECD) group (odds ratio [OR], 1.102; P = .027), but it lost significance in the ECD group (P = .67).

CONCLUSIONS

Terminal donor CRP was associated with DGF in kidney transplant recipients and proved to be mostly significant in younger donors.

Kidney Transplant With Low Levels of DSA or Low Positive B-Flow Crossmatch: An Underappreciated Option for Highly Sensitized Transplant Candidates

BACKGROUND

Avoiding donor-specific antibody (DSA) is difficult for sensitized patients. Improved understanding of the risk of low level DSA is needed.

METHODS

We retrospectively compared the outcomes of 954 patients transplanted with varied levels of baseline DSA detected by single antigen beads and B flow cytometric crossmatch (XM). Patients were grouped as follows: -DSA/-XM, +DSA/-XM, +DSA/low +XM, +DSA/high +XM, and -DSA/+XM and followed up for a mean of 4.1 ± 1.9 years (similar among groups, P = 0.49).

RESULTS

Death-censored allograft survival was similar in all groups except the +DSA/high +XM group, which was lower at 79.1% versus 96.2% in the -DSA/-XM group (P < 0.01). The incidence of chronic antibody-mediated rejection (CAMR) based on surveillance biopsy was higher with increasing DSA (8.2% -DSA/-XM, 17.0% +DSA/-XM, 30.6% +DSA/low +XM, and 51.2% +DSA/high +XM, P < 0.01), but similar in groups without baseline DSA (8.1% -DSA/-XM vs 15.4% -DSA/+XM, P = 0.19). Having a calculated panel-reactive antibody (cPRA) of 80% or greater was independently associated with CAMR (hazard ratio, 5.2; P = 0.03) even when DSA was undetected at baseline. By 2 years posttransplant, the incidence of CAMR was 19.4% in patients with cPRA of 80% or greater and undetected DSA and negative XM at baseline.

CONCLUSIONS

Kidney transplantation with low-level DSA with or without a low positive XM is a reasonable option for highly sensitized patients and may be advantageous compared with waiting for a negative XM deceased donor. The risk for CAMR is low in patients with no DSA even if the XM is positive. Patients with cPRA of 80% or greater are at risk for CAMR even if no DSA is detected.

The effect of pre-operative methylprednisolone on the incidence of delayed graft function in renal transplantation

Introduction:

This study explores the effect of different corticosteroid administration timings on the incidence of slow/delayed graft function.

Methods:

One hundred and twelve kidney transplants from January 2011 to March 2014 were retrospectively analysed. Thirty-six cases were excluded because they were donor-specific antibody positive ( n=16), received thymoglobulin/plasma exchange ( n=11), were ABO-incompatible ( n=6) or suffered graft loss from vascular thrombosis within the first week post-transplant ( n=3). The study period straddled three eras of corticosteroid administration, from intra-operative intravenous (IV) hydrocortisone (Era 1; n=26), to intra-operative IV methylprednisolone (Era 2; n=38) and pre-operative IV methylprednisolone (Era 3; n=12). The primary endpoint was the incidence of slow/delayed graft function. Secondary outcomes included estimated glomerular filtration rate at discharge and 120 and 365 days, rejection (acute and one-year), wound complications, post-transplant diabetes, increase in low-density lipoprotein or body mass index, and cytomegalovirus or BK viraemia within one year.

Results:

On univariate analysis, pre-operative methylprednisolone was associated with lower incidence of slow/delayed graft function (17%, 55%, 58% in Eras 3, 2, 1 respectively; p=0.041), superior estimated glomerular filtration rate at discharge (median 56, 37 and 43 ml/min for Eras 3, 2, 1 respectively; p=0.033) and at 120 days (median 60, 52, and 46 ml/min for Eras 3, 2, 1 respectively; p=0.017). On multivariate analysis, pre-operative IV methylprednisolone ( vs. Eras 1 and 2 combined; odds ratio 4.79 (90% confidence interval 1.16–19.80); p=0.07) and living donor type ( vs. deceased; odds ratio 5.56 (90% confidence interval 2.25–13.77); p=0.002) were associated with lower incidence of slow/delayed graft function.

Conclusion:

Pre-operative methylprednisolone was associated with reduced slow/delayed graft function and improved early estimated glomerular filtration.

Hypothermic Machine Perfusion Reduced Inflammatory Reaction by Downregulating the Expression of Matrix Metalloproteinase 9 in a Reperfusion Model of Donation After Cardiac Death

The exact mechanism by which hypothermic machine perfusion (HMP) improves the graft quality in kidney transplantation of donation after cardiac death (DCD) remains unclear. The aim of this study was to investigate the correlation between the expression of matrix metalloproteinase 9 (MMP-9) and inflammatory reaction in kidney ischemia-reperfusion (I/R) injury injury followed by cold storage (CS) or HMP model of DCD. New Zealand white rabbit kidneys were subjected to 35 min of warm ischemia and 1 h reperfusion, then preserved by either 1 h reperfusion (sham-operated group), 4 h CS or 4 h HMP in vivo. Kidneys were reperfused 24 h followed by further analysis. No treatment was given to rabbits in the normal control group. The expression of MMP-9, nuclear factor-κB (NF-κB), and MMP-2 mRNA were detected by real-time PCR (RT-PCR). MMP-9 was located by immunohistochemistry and immunofluorescence methods. Tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), myeloperoxidase (MPO), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured by kits for each groups. Compared with the CS group, the expression of MMP-9 and NF-κB mRNA were downregulated in HMP group (P < 0.05). In contrast, expression of MMP-2 mRNA had no statistical significance between CS group and HMP group (P > 0.05). In normal control and sham-operated groups, a low level of MMP-9 expression was detected in glomeruli. However, positive signals of MMP-9 were mostly located in the tubulointerstitium and the vascular wall of CS and HMP groups. Expression of TNF-α, IL-6, MDA, and activity of MPO decreased while activity of SOD in the HMP group increased in contrast to the CS group (P < 0.05). In conclusion, inflammatory cytokines mediated MMP-9 expression through NF-κB band to MMP-9 promoter region, resulting in renal injury. Therefore, HMP reduced inflammatory reaction by downregulating the expression of MMP-9, which may be the mechanism of kidney protection in I/R injury.

Identification of Molecular Markers of Delayed Graft Function Based on the Regulation of Biological Ageing

Introduction

Delayed graft function is a prevalent clinical problem in renal transplantation for which there is no objective system to predict occurrence in advance. It can result in a significant increase in the necessity for hospitalisation post-transplant and is a significant risk factor for other post-transplant complications.

Methodology

The importance of microRNAs (miRNAs), a specific subclass of small RNA, have been clearly demonstrated to influence many pathways in health and disease. To investigate the influence of miRNAs on renal allograft performance post-transplant, the expression of a panel of miRNAs in pre-transplant renal biopsies was measured using qPCR. Expression was then related to clinical parameters and outcomes in two independent renal transplant cohorts.

Results

Here we demonstrate, in two independent cohorts of pre-implantation human renal allograft biopsies, that a novel pre-transplant renal performance scoring system (GRPSS), can determine the occurrence of DGF with a high sensitivity (>90%) and specificity (>60%) for donor allografts pre-transplant, using just three senescence associated microRNAs combined with donor age and type of organ donation.

Conclusion

These results demonstrate a relationship between pre-transplant microRNA expression levels, cellular biological ageing pathways and clinical outcomes for renal transplantation. They provide for a simple, rapid quantitative molecular pre-transplant assay to determine post-transplant allograft function and scope for future intervention. Furthermore, these results demonstrate the involvement of senescence pathways in ischaemic injury during the organ transplantation process and an indication of accelerated bio-ageing as a consequence of both warm and cold ischaemia.

Neutrophil Gelatinase Associated Lipocalin Is an Early and Accurate Biomarker of Graft Function and Tissue Regeneration in Kidney Transplantation from Extended Criteria Donors

Background

Delayed graft function (DGF) is an early complication of kidney transplantation (KT) associated with increased risk of early loss of graft function. DGF increases using kidneys from extended criteria donors (ECD). NGAL is a 25KDa protein proposed as biomarker of acute kidney injury. The aim of this study was to investigate the role of NGAL as an early and accurate indicator of DGF and Tacrolimus (Tac) toxicity and as a mediator of tissue regeneration in KT from ECD.

Methods

We evaluated plasma levels of NGAL in 50 KT patients from ECD in the first 4 days after surgery or after Tac introduction.

Results

Plasma levels of NGAL at day 1 were significantly higher in DGF group. In the non DGF group, NGAL discriminated between slow or immediate graft function and decreased more rapidly than serum creatinine. NGAL increased after Tac introduction, suggesting a role as marker of drug toxicity. In vitro, hypoxia and Tac induced NGAL release from tubular epithelial cells (TEC) favoring an autocrine loop that sustains proliferation and inhibits apoptosis (decrease of caspases and Bax/Bcl-2 ratio).

Conclusions

NGAL is an early and accurate biomarker of graft function in KT from ECD favoring TEC regeneration after ischemic and nephrotoxic injury.

Late acute rejection: incidence, risk factors, and effect on graft survival and function

Long-term graft survival and function has not kept pace with short-term success in kidney transplant (Tx) recipients. LAR ≥6 months post-Tx may contribute to lack of improvement; risk factors for LAR are not well known. Of 64 Tx recipients followed over six yr, 23 (35.9%) had LAR (LAR group) and 41 had no LAR (no LAR group). Of all variables, significant risk factors for LAR included DGF, (43.4% LAR vs. 14.6% in no LAR group, p = 0.0096); de novo DSA (65.2% vs. 26.8%, p = 0.003); mean COV% of TAC (41.8% vs. 34.6%, p = 0.03); and non-adherence (34.8% vs. 7.3%, p = 0.0043). DGF and DSA remained statistically significant (p = 0.002 and 0.003, respectively); COV% TAC had borderline significance (p = 0.057), and non-adherence was not significant on multivariate regression analysis. Patients with LAR had inferior graft survival and function, whereas graft function was stable in the no LAR group over a mean follow-up of 31.2 months. Patients with de novo DSA and DGF should be considered at risk of LAR; an early diagnosis and treatment of LAR may improve graft survival and function.

Obesity in kidney transplantation

Kidney transplantation is the preferred modality of renal replacement therapy. Long-term patient and graft survival have only improved marginally over the recent decade, mainly because of the development of cardiovascular disease after transplantation. Obesity is a risk factor for cardiovascular disease and is common before and after transplantation. This article reviews the literature assessing the role of pre- and post-transplant obesity on patient and graft survival, discusses the underlying obesity-related mechanisms leading to inferior kidney transplant outcomes, and explores the role of nutritional intervention on improving long-term outcomes of transplantation. Although the role of pretransplant obesity remains uncertain, post-transplant obesity increases the risk of graft failure and mortality. Nutritional intervention is effective in achieving post-transplant weight loss, but the effect on long-term outcomes has not been established. Future research should focus on conducting nutritional intervention studies aiming to improve long-term outcomes of kidney transplantation.

The prognostic value of time needed on dialysis in patients with delayed graft function

INTRODUCTION

We hypothesize that in patients with delayed graft function (DGF), the need for a longer time needed on dialysis (TND) post-kidney transplant is associated with poorer long-term function and an increase in complications.

METHODS

This was a retrospective chart review involving collaboration between Western University (WU) Renal Transplant Program of London, Ontario and the Saskatchewan renal transplant program (SRTP). A total of 774 patients (567 WU and 207 SRTP) received kidney transplants between 2004 and 2011, of which 83 patients with deceased donor transplants (59 WU and 24 SRTP) developed DGF, defined as the need for dialysis in the first week posttransplant.

RESULTS

Patients with DGF were divided into three groups depending on TND [group 1: <7 days (n = 52), group 2: 7-14 days (n = 13) and group 3 (n = 18): >14 days]. The creatinine clearance (CrCl) at 30 days (42.5, 33.8, 20.0 cc/min; P < 0.001) and 1 year (56.7, 49.2, 37.3 cc/min, P = 0.031) were significantly different between the three groups. Multivariate regression analysis identified length of TND posttransplant (β = -0.5, P < 0.001) and donation after cardiac death (DCD) donor (β = 19.5, P < 0.001) as the most significant predictors of CrCl at 1 year in these patients with DGF. DCD kidneys with DGF had a higher CrCl at 1 year and fewer readmissions in the first year compared with non-DCD kidneys with DGF.

DISCUSSION

Our study suggests that increased TND is associated with worse CrCl at 1 year. The data also support the hypothesis of a different mechanism for DGF in DCD and non-DCD kidneys.

Is delayed graft function causally associated with long-term outcomes after kidney transplantation? Instrumental variable analysis

BACKGROUND

Although some studies have found an association between delayed graft function (DGF) after kidney transplantation and worse long-term outcomes, a causal relationship remains controversial. We investigated this relationship using an instrumental variables model (IVM), a quasi-randomization technique for drawing causal inferences.

METHODS

We identified 80,690 adult, deceased-donor, kidney-only transplant recipients from the Scientific Registry of Transplant Recipients between 1997 and 2010. We used cold ischemia time (CIT) as an instrument to test the hypothesis that DGF causes death-censored graft failure and mortality at 1 and 5 years after transplantation, controlling for an array of characteristics known to affect patient and graft survival. We compared our IVM results with a multivariable linear probability model.

RESULTS

DGF occurred in 27% of our sample. Graft failure rates at 1 and 5 years were 6% and 22%, respectively, and 1-year and 5-year mortality rates were 5% and 20%, respectively. In the linear probability model, DGF was associated with increased risk of both graft failure and mortality at 1 and 5 years (P<0.001). In the IVM, we found evidence suggesting a causal relationship between DGF and death-censored graft failure at both 1 year (13.5% increase; P<0.001) and 5 years (16.2% increase; P<0.001) and between DGF and mortality at both 1 year (7.1% increase; P<0.001) and 5 years (11.0% increase; P<0.01). Results were robust to exclusion of lower quality as well as pumped kidneys and use of a creatinine-based definition for DGF.

CONCLUSION

Instrumental variables analysis supports a causal relationship between DGF and both graft failure and mortality.

Efficacy and safety of thymoglobulin and basiliximab in kidney transplant patients at high risk for acute rejection and delayed graft function

OBJECTIVES

To compare the efficacy and safety of thymoglobulin compared with basiliximab in patients who had kidney transplants and are at high risk for acute rejection and delayed graft function.

MATERIALS AND METHODS

A retrospective review of patients who had 1 or more risk factors for acute rejection and delayed graft function and who were given either thymoglobulin or basiliximab for induction therapy. Incidences of acute rejection, antibody-treated acute rejection, delayed graft function, chronic rejection, cancer, infection, leucopenia, and thrombocytopenia were compared between thymoglobulin and basiliximab groups. Serum creatinine levels within 1 year and long-term graft and patient survival also were compared.

RESULTS

A total of 327 patients were included. Incidences of acute rejection, antibody-treated acute rejection, delayed graft function, and chronic rejection were significantly lower in the thymoglobulin group than in the basiliximab group (P < .05). Serum creatinine levels were lower in the thymoglobulin group on postoperative days 7, 14, and 30 (P < .05). There were no statistically significant differences regarding long-term graft and patient survival, cancer, or total infection rate between the groups. Incidences of Cytomegalovirus infection, leucopenia, and thrombocytopenia were significantly higher in the thymoglobulin group (P < .05).

CONCLUSIONS

Thymoglobulin may improve short-term outcomes, compared with basiliximab, in patients who had kidney transplants and are at high risk for acute rejection and delayed graft function. However, long-term outcomes are similar with thymoglobulin and basiliximab.

Slow early graft function: a neglected entity after renal transplantation

BACKGROUND

After renal transplantation, early graft function (EGF) can be divided into delayed graft function (DGF), slow graft function (SGF) and immediate graft function (IGF). DGF is well documented. However, when evaluating the long-term significance of early function, the literature shows conflicting definitions and inconsistent results. In addition, SGF, a new entity separate to DGF and IGF, is a recent and poorly understood development.

AIM

To investigate the risk factors for and the impact of poor EGF (PEGF) on long-term outcome.

METHODS

This retrospective study reviewed the records of local adult patients who underwent renal transplantation at the Groote Schuur Hospital (Cape Town, South Africa) between 2004 and 2008. EGF was divided according to day 5 serum creatinine into IGF (serum creatinine <150 µmol/l), SGF (serum creatinine >150 but <450 µmol/l) and DGF (serum creatinine >450 µmol/l or dialysis in the first week). DGF and SGF together comprised PEGF, with IGF alone representing good EGF (GEGF).

RESULTS

A total of 121 patients (77 men, 44 women; mean age 39 years, range 14-67) were included in the study. Eighteen were excluded due to nephrectomy (n = 8), death (n = 6) or loss to follow-up (n = 4) within the first year. Analysis of cadaveric donors showed no significant risk factors for PEGF with the exception of cold ischaemic time, which differed significantly between the GEGF and PEGF groups, with means of 12 and 16 h, respectively (p = 0.013). Considering both living and cadaveric grafts, the 1-year estimated glomerular filtration rate (eGFR) was significantly different between IGF and DGF (p = 0.038) as well as between IGF and SGF (p = 0.028), with no significant difference between SGF and DGF (p > 0.05). A comparison of the PEGF and GEGF groups yielded significantly different 1-year eGFR values (60 and 50 ml/min, respectively; p = 0.07), with PEGF also associated with a longer hospital stay (20 vs. 14 days; p = 0.00005). Acute rejection was independently associated with a lower 1-year eGFR (p = 0.028), but in the absence of rejection, GEGF and PEGF remained significantly different with regards to 1-year eGFR (p = 0.024).

CONCLUSIONS

SGF is not related to IGF but rather to DGF and should thus be regarded as a form of PEGF as opposed to GEGF. PEGF has a worse long-term outcome, and this indicates the need for increased efforts in its prevention and greater attention to its management.

Induction therapy by anti-thymocyte globulin (rabbit) versus basiliximab in deceased donor renal transplants and the effect on delayed graft function and outcomes

The use of induction therapy significantly reduces the incidence of acute rejection (AR) episodes posttransplantation and prevents delayed graft function (DGF). In our program, all adult deceased donor kidney transplant (DDKT) recipients receive immunosuppression induction therapy with either basiliximab (anti-CD25 Ab) or rabbit anti-thymocyte globulin (RATG). Our protocol is risk adjusted such that patients who are at a higher risk for DGF or AR received RATG and all other patients receive anti-CD25 Ab. We hypothesized that treating our higher-risk patients with RATG induction at the time of transplantation would lead to a lower rate of DGF and better outcomes. From August 1, 2005 through August 31, 2010, 116 consecutive adult patients received a DDKT in a single academic transplantation center. All DDKT patients received induction with RATG or anti-CD25 Ab. The induction decision was made prior to transplantation based on donor and recipient risk factors for AR and DGF. Transplants that were deemed at higher risk for DGF or AR based on donor factors or recipient factors received RATG. Medical records and patient databases were reviewed retrospectively. The use of RATG in higher-risk recipients for DGF and AR did not significantly reduce the DGF rate. At 6 months the function of the allograft function measured as creatinine clearance or serum creatinine was lower in the RATG group than the patients who received anti-CD25 Ab induction. The choice of induction therapy did not improve outcomes in high-risk patients in this short-term study.

Impact of early kidney resistance index on kidney graft and patient survival during a 5-year follow-up

BACKGROUND

Resistance index (RI) measured by Doppler sonography during the early post-transplant period reflects interstitial oedema within the transplanted kidney. We have prospectively analysed the relationship between RI measured shortly after kidney transplantation (KTx), patient and graft survival, as well as kidney graft function during a 5-year follow-up.

METHODS

RI was measured at the second to fourth day after KTx in 364 consecutive patients, who were divided into tertiles, according to baseline RI value (Group 1: RI < 0.73, Group 2: RI between 0.73 and 0.85 and Group 3: RI > 0.85). The kidney graft function [estimated glomerular filtration rate (eGFR)] during the follow-up period was calculated according to the Modification of Diet in Renal Disease formula.

RESULTS

During the 5-year follow-up period, 23 patients died (2.6 versus 6.5 versus 9.6% in RI tertiles, respectively) and 59 lost their kidney graft (12.1 versus 17.7 versus 18.4%, respectively). Survival analyses showed that the effect of RI was significant for a combined outcome [graft loss or death; hazard ratio (HR) = 10.88] and in relation to death, it was of borderline significance (HR = 45.3, P = 0.09). The effect of delayed graft function (DGF) was only significant on graft loss (HR = 1.73). eGFR in the highest tertile was lower than in the lowest tertile during the entire follow-up period.

CONCLUSIONS

High RI values measured in segmental arteries in the very early post-transplant period predict worse kidney graft function and increased risk of all-cause graft loss, including patient death in the 5-year follow-up period. (ii) The predictive value of RI is not completely independent from the adverse influence of DGF on the premature graft loss.

The clinical and financial burden of early dialysis after deceased donor kidney transplantation

Background

The economic implications of dialysis-requiring allograft dysfunction early after kidney transplantation are not well-described.

Methods

Data for Medicare-insured adult kidney transplant recipients in 1995-2004 who did not develop permanent graft failure in the first 90 days were drawn from the United States Renal Data System. We identified dialysis treatment records from Medicare claims and categorized patients according to frequency and duration of post-transplant dialysis as: first week (delayed graft function, DGF), second week, weeks 3 or 4, second month, or third month. Associations of dialysis requirements with Medicare payments for the transplant hospitalization and over the next three years were estimated with multivariable linear regression. Graft and patient survival according to early dialysis requirements were examined with multivariable survival analysis.

Results

Among 37,533 recipients, 15,314 (41%) experienced DGF and 3,184 (21% of those with DGF) received dialysis beyond the first week. Compared with no dialysis in the first 3 months, adjusted marginal first-year costs associated with early post-transplant dialysis ranged from $6,467 for dialysis requirement limited to first week to $27,606 for dialysis in multiple periods (p<0.0001). Patients who experienced DGF and received dialysis in >2 early periods were more than twice as likely to lose their grafts within 3 years as those without early dialysis requirements.

Conclusions

While dialysis in the first week post-transplant is an adverse risk marker, early dialysis in weeks 2 to 12 is associated with similarly adverse, if not worse, costs and clinical consequences. This observation supports a need for broader definition of DGF.

Pretransplant transcriptome profiles identify among kidneys with delayed graft function those with poorer quality and outcome

Robust biomarkers are needed to identify donor kidneys with poor quality associated with inferior early and longer-term outcome. The occurrence of delayed graft function (DGF) is most often used as a clinical outcome marker to capture poor kidney quality. Gene expression profiles of 92 preimplantation biopsies were evaluated in relation to DGF and estimated glomerular filtration rate (eGFR) to identify preoperative gene transcript changes associated with short-term function. Patients were stratified into those who required dialysis during the first week (DGF group) versus those without (noDGF group) and subclassified according to 1-month eGFR of >45 mL/min (eGFR(hi)) versus eGFR of ≤45 mL/min (eGFR(lo)). The groups and subgroups were compared in relation to clinical donor and recipient variables and transcriptome-associated biological pathways. A validation set was used to confirm target genes. Donor and recipient characteristics were similar between the DGF versus noDGF groups. A total of 206 probe sets were significant between groups (P < 0.01), but the gene functional analyses failed to identify any significantly affected pathways. However, the subclassification of the DGF and noDGF groups identified 283 probe sets to be significant among groups and associated with biological pathways. Kidneys that developed postoperative DGF and sustained an impaired 1-month function (DGF(lo) group) showed a transcriptome profile of significant immune activation already preimplant. In addition, these kidneys maintained a poorer transplant function throughout the first-year posttransplant. In conclusion, DGF is a poor marker for organ quality and transplant outcome. In contrast, preimplant gene expression profiles identify "poor quality" grafts and may eventually improve organ allocation.

Assessment of kidney organ quality and prediction of outcome at time of transplantation

The critical importance of donor organ quality, i.e., number of surviving nephrons, ability to withstand injury, and capacity for repair in determining short- and long-term outcomes is becoming increasingly clear. This review provides an overview of studies to assess donor kidney quality and subsequent transplant outcomes based on clinical pathology and transcriptome-based variables available at time of transplantation. Prediction scores using clinical variables function when applied to large data sets but perform poorly for the individual patient. Histopathology findings in pre-implantation or post-reperfusion biopsies help to assess structural integrity of the donor kidney, provide information on pre-existing donor disease, and can serve as a baseline for tracking changes over time. However, more validated approaches of analysis and prospective studies are needed to reduce the number of discarded organs, improve allocation, and allow prediction of outcomes. Molecular profiling detects changes not seen by morphology or captured by clinical markers. In particular, molecular profiles provide a quantitative measurement of inflammatory burden or immune activation and reflect coordinated changes in pathways associated with injury and repair. However, description of transcriptome patterns is not an end in itself. The identification of predictive gene sets and the application to an individualized patient management needs the integration of clinical and pathology-based variables, as well as more objective reference markers of transplant function, post-transplant events, and long-term outcomes.

Effect of hemodialysis before transplant surgery on renal allograft function--a pair of randomized controlled trials

BACKGROUND

Hemodialysis immediately before kidney transplant surgery has been suggested to adversely affect early graft function. On the other hand, considering its profound antiinflammatory effects, a beneficial impact of regional citrate anticoagulation on the evolution of graft function can be speculated. We sought to assess the clinical impact of preoperative hemodialysis and dialysis anticoagulation in two related randomized trials.

METHODS

Eligible kidney transplant candidates with a serum potassium less than or equal to 5.0 mEq/L were randomized to receive dialysis or no dialysis before deceased donor transplantation. Patients with a potassium more than 5.0 mEq/L were randomized to receive dialysis with heparin or citrate anticoagulation. The primary endpoint was the estimated glomerular filtration rate (eGFR) at posttransplant day 5.

RESULTS

The first comparison (56 vs. 54 patients) revealed no effect of dialysis on eGFR at day 5 (primary endpoint, 12 [interquartile range 5-36] vs. 13 [5-37] mL/min/1.73 m2, P=0.98), rates of delayed graft function (22% vs. 27%, P=0.66), cellular rejection (20% vs. 24%, P=0.65), and C4d-positive dysfunction (2% vs. 9%, P=0.11) or 1-year death-censored graft survival (89% vs. 91%, P=0.51). Comparing citrate with heparin anticoagulation (44 vs. 66 patients), no differences in eGFR at day 5 (17 [8-31] vs. 14 [6-38] ml/min/1.73 m2, P=0.57), delayed graft function (21% vs. 30%, P=0.28), cellular rejection (23% vs. 33%, P=0.29), and graft survival (90% vs. 88%, P=0.44) were found. For citrate anticoagulation, less C4d-positive rejection episodes (P=0.08) and higher 1-year eGFR levels (P=0.03) were observed.

CONCLUSION

Pretransplant hemodialysis and anticoagulation may not affect early graft function in a meaningful way.

ABCB1 genotypes predict cyclosporine-related adverse events and kidney allograft outcome

Cyclosporine A (CsA) is a substrate of P-glycoprotein, an efflux transporter encoded by the ABCB1 gene. Compared with carriers of the wild-type gene, carriers of T allelic variants in exons 21 or 26 have reduced P-glycoprotein activity and, secondarily, increased intracellular concentration of CsA; therefore, carriers of T variants might be at increased risk for CsA-related adverse events. We evaluated the associations between ABCB1 genotypes (in exons 12, 21, and 26) and CsA-related outcomes in 147 renal transplant recipients who were receiving CsA-based immunosuppression and were included in the Mycophenolate Steroids Sparing study. During a median of 65.5 mo follow-up, carriers of T allelic variants in exons 21 or 26 had a three-fold risk for delayed graft function (DGF), a trend to slower recovery of renal function and lower GFR at study end, and significantly higher incidences of new-onset diabetes and cytomegalovirus reactivation compared with carriers of the wild-type genotype. T variants in both exons 21 and 26 were independently associated with 3.8- and 3.5-fold higher risk for DGF, respectively (P = 0.022 and P = 0.034). The incidence of acute rejection and the mean CsA dose and blood levels were comparable in genotype groups. In conclusion, renal transplant recipients with T allelic variants in ABCB1 exons 21 or 26 are at increased risk for CsA-related adverse events. Genetic evaluation may help to identify patients at risk and to modulate CsA therapy to optimize graft and patient outcomes.

Oncostatin M pathway plays a major role in the renal acute phase response

The acute phase response is traditionally characterized by hepatic synthesis of proteins as an inflammatory response to injury, with interleukin-6 (IL-6) being the key mediator. In contrast, microarray studies in human renal transplant implantation biopsies indicate a strong acute phase response in the deceased donor kidney, associated with a significant upregulation of oncostatin M receptor β (OSMR). The aim of this study was to determine whether the kidney can generate a strong acute phase response, mediated by the OSM/OSMR gateway. Genes associated with the IL-6 cytokine family and acute phase reactants were analyzed by real-time RT-PCR in four groups of human biopsies spanning a spectrum of renal injury. OSM, OSMR, and fibrinogen β (FGB) were progressively more highly expressed from prenephrectomy, living donor, deceased donor, to discarded donor kidneys, suggesting correlation with severity of injury and local renal synthesis. Acute phase response gene expression was analyzed in human proximal tubular cells in culture in response to OSM. OSM induced a significant increase in expression of FGB, OSMR, serpin peptidase inhibitor A1, IL-6, and lipopolysaccharide binding protein, and a decrease in IL-6R. These changes were largely attenuated by coincubation with an OSMR blocking antibody, indicating the OSM effect was mediated through OSMR. OSM also resulted in a significantly altered expression of acute phase genes compared with IL-6 or leukemia inhibitory factor, suggesting that OSM is the predominant cytokine mediating the renal tubular acute phase response. In conclusion, the renal parenchyma is capable of generating a strong acute phase response, likely mediated via OSM/OSMR.