Rescue Allocation Modes in Eurotransplant Kidney Transplantation: Recipient Oriented Extended Allocation Versus Competitive Rescue Allocation-A Retrospective Multicenter Outcome Analysis

BACKGROUND

Whenever the kidney standard allocation (SA) algorithms according to the Eurotransplant (ET) Kidney Allocation System or the Eurotransplant Senior Program fail, rescue allocation (RA) is initiated. There are 2 procedurally different modes of RA: recipient oriented extended allocation (REAL) and competitive rescue allocation (CRA). The objective of this study was to evaluate the association of patient survival and graft failure with RA mode and whether or not it varied across the different ET countries.

METHODS

The ET database was retrospectively analyzed for donor and recipient clinical and demographic characteristics in association with graft outcomes of deceased donor renal transplantation (DDRT) across all ET countries and centers from 2014 to 2021 using Cox proportional hazards methods.

RESULTS

Seventeen thousand six hundred seventy-nine renal transplantations were included (SA 15 658 [89%], REAL 860 [4.9%], and CRA 1161 [6.6%]). In CRA, donors were older, cold ischemia times were longer, and HLA matches were worse in comparison with REAL and especially SA. Multivariable analyses showed comparable graft and recipient survival between SA and REAL; however, CRA was associated with shorter graft survival. Germany performed 76% of all DDRTs after REAL and CRA and the latter mode reduced waiting times by up to 2.9 y.

CONCLUSIONS

REAL and CRA are used differently in the ET countries according to national donor rates. Both RA schemes optimize graft utilization, lead to acceptable outcomes, and help to stabilize national DDRT programs, especially in Germany.

Excellent efficacy and beneficial safety during observational 5-year follow-up of rapid steroid withdrawal after renal transplantation (Harmony FU study)

BACKGROUND

We previously reported excellent efficacy and improved safety aspects of rapid steroid withdrawal (RSWD) in the randomized controlled 1-year "Harmony" trial with 587 predominantly deceased-donor kidney transplant recipients randomized either to basiliximab or rabbit antithymocyte globulin induction therapy and compared with standard immunosuppressive therapy consisting of basiliximab, low tacrolimus once daily, mycophenolate mofetil and corticosteroids.

METHODS

The 5-year post-trial follow-up (FU) data were obtained in an observational manner at a 3- and a 5-year visit only for those Harmony patients who consented to participate and covered clinical events that occurred from the second year onwards.

RESULTS

Biopsy-proven acute rejection and death-censored graft loss rates remained low and independent of RSWD. Rapid steroid withdrawal was an independent positive factor for patient survival (adjusted hazard ratio 0.554, 95% confidence interval 0.314-0.976; P = .041).The reduced incidence of post-transplantation diabetes mellitus in RSWD patients during the original 1-year study period was not compensated by later incidences during FU. Incidences of other important outcome parameters such as opportunistic infections, malignancies, cardiovascular morbidity/risk factors, donor-specific antibody formation or kidney function did not differ during FU period.

CONCLUSIONS

With all the limitations of a post-trial FU study, the Harmony FU data confirm excellent efficacy and beneficial safety aspects of RSWD under modern immunosuppressive therapy over the course of 5 years after kidney transplantation in an immunologically low-risk, elderly population of Caucasian kidney transplant recipients. Trial registration: Clinical trial registration number: Investigator Initiated Trial (NCT00724022, FU study DRKS00005786).

Human Leucocyte Antigen-Matching Can Improve Long Term Outcome of Renal Allografts from Donors Older Than 75 Years

BACKGROUND

Renal transplantation is the therapy of choice for kidney failure. The Eurotransplant Senior Program (ESP) has been established to allocate kidneys ≥65 years to recipients of the same age group considered a regional allocation with short cold ischemia (CIT) but not human-leukocyte-antigen (HLA)-matching. The acceptance of organs aged ≥75 years is also still controversial within the ESP.

METHODS

In a multicenter approach, 179 kidney grafts ≥75 years (mean donor age 78 years) that were transplanted in 174 patients in 5 German transplant centers were analyzed. The primary focus of the analysis was long-term outcome of the grafts and the impact of CIT, HLA matching, and recipient related risk factors.

RESULTS

The mean graft survival was 59 months (median 67 months) with a mean donor age of 78.3 ± 2.9 years. Grafts with 0 to 3 HLA-mismatches had a significantly better overall graft survival compared to grafts with ≥4 mismatches (69 months vs 54 months; P = .008). The mean CIT was short (11.9 ± 5.3 hours) and had no impact on graft survival.

CONCLUSION

Recipients receiving a kidney graft from donors aged ≥75 years can benefit from nearly 5 years of survival with a functioning graft. Even minimal HLA matching may improve long term allograft survival.

Kidney Transplantation After Rescue Allocation-the Eurotransplant Experience: A Retrospective Multicenter Outcome Analysis

BACKGROUND

At Eurotransplant (ET), kidneys are transferred to "rescue allocation" (RA), whenever the standard allocation (SA) algorithms Eurotransplant Kidney Allocation System (ETKAS) and Eurotransplant Senior Program (ESP) fail. We analyzed the outcome of RA.

METHODS

Retrospective patient clinical and demographic characteristics association analyses were performed with graft outcomes for 2422 recipients of a deceased donor renal transplantation (DDRT) after RA versus 25 481 after SA from 71 centers across all ET countries from 2006 to 2018.

RESULTS

Numbers of DDRTs after RA increased over the time, especially in Germany. RA played a minor role in ESP versus ETKAS (2.7% versus 10.4%). RA recipients and donors were older compared with SA recipients and donors, cold ischemia times were longer, waiting times were shorter, and the incidence of primary nonfunction was comparable. Among ETKAS recipients, HLA matching was more favorable in SA (mean 3.7 versus 2.5). In multivariate modeling, the incidence of graft loss in ETKAS recipients was reduced in RA compared with SA (subdistribution hazard ratio, 0.80; 95% confidence interval [0.70-0.91], P < 0.001), whereas other outcomes (mortality, death with functioning graft (DwFG)) were not significantly different. None of the 3 outcomes were significantly different when comparing RA with SA within the ESP program.

CONCLUSIONS

Facing increased waiting times and mortality on dialysis due to donor shortage, this study reveals encouragingly positive DDRT outcomes following RA. This supports the extension of RA to more patients and as an alternative tool to enable transplantation in patients in countries with prohibitively long waiting times or at risk of deterioration.

A noninvasive diagnostic approach to retrospective donor HLA typing in kidney transplant patients using urine

Antibody-mediated rejection (AMR) is a major obstacle to long-term kidney transplantation. AMR is mostly caused by donor specific HLA antibodies, which can arise before or any time after transplantation. Incomplete donor HLA typing and unavailability of donor DNA regularly preclude the assessment of donor-specificity of circulating anti-HLA antibodies. In our centre, this problem arises in approximately 20% of all post-transplant HLA-antibody assessments. We demonstrate that this diagnostic challenge can be resolved by establishing donor renal tubular cell cultures from recipient´s urine as a source of high-quality donor DNA. DNA was then verified for genetic origin and purity by fluorescence in situ hybridization and short tandem repeat analysis. Two representative cases highlight the diagnostic value of this approach which is corroborated by analysis of ten additional patients. The latter were randomly sampled from routine clinical care patients with available donor DNA as controls. In all 12 cases, we were able to perform full HLA typing of the respective donors confirmed by cross-comparison to results from the stored 10 donor DNAs. We propose that this noninvasive diagnostic approach for HLA typing in kidney transplant patients is valuable to determine donor specificity of HLA antibodies, which is important in clinical assessment of suspected AMR.

[Kidney as pacemaker for cardiovascular aging]

Kidney patients age faster and vascular risk factors intensify the process. Lifetime is reduced up to 16 years in patients with diabetes mellitus type 2 and kidney disease. SGLT2 inhibitors play a significant role in maintaining organ function. By inhibiting the SGLT2 transporter in the proximal tubule of the kidneys, energy and water are continuously excreted and metabolic processes that are counter-regulated are set in motion. This hypometabolic adaptation supports organ functions and induces longevity. Kidney protection extends life expectancy of patients with diabetes mellitus type 2.Also patients with heart failure benefit and a 3-stage therapy is newly being discussed. The beta blocker is combined with an SGLT2 inhibitor in the first stage. In the second stage, the angiotensin receptor/neprilysin inhibitor and then a mineralocorticoid receptor antagonist (MRA) is used. These therapies have a complementary effect.

Color-coded summation images in the evaluation of renal artery stenosis before and after percutaneous transluminal angioplasty

BACKGROUND

Endovascular therapy is the gold standard in patients with hemodynamic relevant renal artery stenosis (RAS) resistant to medical therapy. The severity grading of the stenosis as well as the result assessment after endovascular approach is predominantly based on visible estimations of the anatomic appearance. We aim to investigate the application of color-coded DSA parameters to gain hemodynamic information during endovascular renal artery interventions and for the assessment of the procedures´ technical success.

METHODS

We retrospectively evaluated 32 patients who underwent endovascular renal artery revascularization and applied color-coded summation imaging on selected monochromatic DSA images. The differences in time to peak (dTTP) of contrast enhancement in predefined anatomical measuring points were analyzed. Furthermore, differences in systolic blood pressure values (SBP) and serum creatinine were obtained. The value of underlying diabetes mellitus as a predictor for clinical outcome was assessed. Correlation analysis between the patients´ gender as well as the presence of diabetes mellitus and dTTP was performed.

RESULTS

Endovascular revascularization resulted in statistically significant improvement in 4/7 regions of interest. Highly significant improvement of perfusion in terms of shortened TTP values could be found at the segmental artery level and in the intrastenotical segment (p < 0.001), significant improvement prestenotical and in the apical renal parenchyma (p < 0.05). In the other anatomic regions, differences revealed not to be significant. Differences between SBP and serum creatinine levels before and after the procedure were significant (p = 0.004 and 0.0004). Patients´ gender as well as the presence of diabetes mellitus did not reveal to be predictors for the clinical success of the procedure. Furthermore, diabetes and gender did not show relevant correlation with dTTP in the parenchymal measuring points.

CONCLUSIONS

The supplementary use of color-coding DSA and the data gained from parametric images may provide helpful information in the evaluation of the procedures´ technical success. The segmental artery might be a particularly suitable vascular territory for analyzing differences in blood flow characteristics. Further studies with larger cohorts are needed to further confirm the diagnostic value of this technique.

The transition clinic in chronic kidney disease care

People with advanced chronic kidney disease and evidence of progression have a high risk of renal replacement therapy. Specialized transition clinics could offer a better option for preparing these patients for dialysis, transplantation or conservative care. This review focuses on the different aspects of such transition clinics. We discuss which patients should be referred to these units and when referral should take place. Patient involvement in the decision-making process is important and requires unbiased patient education. There are many themes, both patient-centred and within the healthcare structure, that will influence the process of shared decision-making and the modality choice. Aspects of placing an access for haemodialysis and peritoneal dialysis are reviewed. Finally, we discuss the importance of pre-emptive transplantation and a planned dialysis start, all with a focus on multidisciplinary collaboration at the transition clinic.

Comparison of different algorithms for the assessment of cardiovascular risk after kidney transplantation by the time of entering waiting list

Background

The prevalence of cardiovascular disease is high among patients with chronic kidney disease and cardiovascular events (CVE) remain the leading cause of death after kidney transplantation (KT). We performed a retrospective analysis of 389 KT recipients to assess if the European Society of Cardiology Score (ESC-Score), Framingham Heart Study Score (FRAMINGHAM), Prospective Cardiovascular Munster Study Score (PROCAM-Score) or Assessing cardiovascular risk using Scottish Intercollegiate Guidelines Network Score (ASSIGN-Score) algorithms can predict cardiovascular risk after KT at the time of entering the waiting list.

Methods

389 KT candidates were scored by the time of entering the waiting list. Pearsons chi-square test, cox regression analysis and survival estimates were performed to evaluate the reliability of the cardiovascular scoring models after successful KT.

Results

During a follow-up of 8 ± 5.8 years, 96 patients (30%) died due to cardiovascular problems, whereas 13.9% suffered non-fatal CVE. Graft loss occurred in 84 patients (21.6%). Predictors of CVE, survival and graft loss were age and the length of end-stage kidney disease. All scores performed well in assessing the risk for CVE (P &lt; 0.01). Receiver-operating characteristic analysis using the ESC-SCORE, as an example, suggested a cut-off for risk stratification and clinical decisions.

Conclusions

We found all tested scores were reliable for cardiovascular assessment. We suggest using cardiac scores for risk assessment before KT and then taking further steps according to current guidelines.

First Treatment of Relapsing Rapidly Progressive IgA Nephropathy With Eculizumab After Living Kidney Donation: A Case Report

BACKGROUND

IgA nephropathy (IGAN) rarely can present as a crescent and progressive form leading to end-stage renal disease (ESRD) in a short period of time. Recurrence of IGAN after kidney transplantation is frequent, and complement components such as C3, C4d, and C5 seem to be involved. We present a case of a young male patient with ESRD caused by rapidly progressive IGAN and who demonstrated rapid recurrence of crescentic IGAN after kidney donation.

CASE REPORT

In September 2014, a 28-year-old male patient was hospitalized due to IGAN with 60% of crescents. Cyclophosphamide, steroids, and plasmapheresis did not prevent ESRD. After 8 months of peritoneal dialysis, the patient received a blood group-compatible living donor kidney from his 57-year-old mother. Immunosuppression consisted of tacrolimus, mycophenolic acid, and steroids without induction therapy. Acute graft failure occurred 2 months later, and graft biopsy results revealed recurrence of crescentic IGAN. Cyclophosphamide was added to tacrolimus and steroid treatment, but graft function could not be restored despite viable kidney tissue in repeated biopsy specimens. Rescue therapy with 4 single doses of eculizumab was introduced while hemodialysis had already been initiated. After a cumulative dose of 1800 mg of eculizumab, kidney function did not recover.

CONCLUSIONS

In this case, eculizumab was not effective in treating IGAN recurrence after transplantation. Therapy was started late when hemodialysis had already been initiated; an earlier start of therapy might be more effective.

Safety and Efficacy of Induction Therapy With Thymoglobulin in AB0-Incompatible Kidney Transplantation

INTRODUCTION

Data suggest an additional role of T cells in antibody-mediated rejections. In 2001 a protocol for AB0-incompatible kidney transplantation based on B-cell-depleting anti-CD20 antibody rituximab, antigen-specific blood group IgG immunoadsorption, intravenous immunoglobulins, and triple immunosuppression was introduced in Europe, which used induction therapy with the use of interleukin-2 receptor antibody (IL2-RA) basiliximab. We used thymoglobulin in AB0-incompatible patients as induction in the face of high immunologic risk.

METHODS

We retrospectively evaluated a cohort of 9 AB0i living donation (LD) recipients from 2011 to 2014. Desensitization included blood group-specific immunoadsorption. Eighteen AB0-compatible LD recipients receiving induction therapy with thymoglobulin served as control subjects. Another control group consisted of 18 AB0-compatible LD recipients receiving basiliximab. Follow-up was 24 months. We captured graft function by estimating glomerular filtration rate (eGFR by Modification of Diet in Renal Disease formula), rejection episodes, and bacterial and viral infections.

RESULTS

All patients experienced immediate graft function. No significant or clinical differences were observed regarding graft function, rejection rates, or infections between the groups, although there seemed to be slightly higher cytomegalovirus infection rates due to preemptive therapy strategy.

CONCLUSIONS

Thymoglobulin appears to be similar in safety and efficacy to IL-2-antagonists in AB0i kidney transplantation.

Successful Short-Term Intravenous Treatment of Disseminated Nocardia farcinica Infection with Severe Hyponatremia After Kidney Transplantation: A Case Report

BACKGROUND

Nocardia is a genus of gram-positive Actinomycetes that are ubiquitous in decaying organic material, soil, and water. Some Nocardia species can infect humans, mainly by airborne transmission. Several reports describe disseminated infections, which are rare and mostly affect strongly immunocompromised patients because intact T-cell-mediated immunity is the major protective mechanism.

CASE REPORT

We report a case of disseminated pulmonary, cerebral, and cutaneous infection with Nocardia farcinica in a 66-year-old kidney transplant recipient treated with low-dose triple immunosuppression. The patient was initially admitted because of severe hyponatremia and pneumonia with radiologic signs of pleural effusion. The infectious agent was isolated when cutaneous lesions developed. Oral trimethoprim/sulfamethoxazole treatment led to severe hyponatremia; therefore, long-term treatment with parenteral amikacin and minocycline was initiated. After 7 months of consistent intravenous treatment, the lesions completely resolved and treatment was stopped, against some expert suggestions. The patient had remained free of relapse at the time of writing.

CONCLUSIONS

Disseminated Nocardia infection in immunocompromised patients is a rare but life-threatening disease. Owing to its infrequency, the variety of clinical patterns, antimicrobial resistance, and often fatal complications of standardized therapy, the diagnosis and treatment of this infection remain challenging and protracted.

Effects of Dopamine Donor Pretreatment on Graft Survival after Kidney Transplantation: A Randomized Trial

BACKGROUND AND OBJECTIVES

Donor dopamine improves initial graft function after kidney transplantation due to antioxidant properties. We investigated if a 4 µg/kg per minute continuous dopamine infusion administered after brain-death confirmation affects long-term graft survival and examined the exposure-response relationship with treatment duration.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Five-year follow-up of 487 renal transplant patients from 60 European centers who had participated in the randomized, multicenter trial of dopamine donor pretreatment between 2004 and 2007 (ClinicalTrials.gov identifier: NCT00115115).

RESULTS

Follow-up was complete in 99.2%. Graft survival was 72.6% versus 68.7% (P=0.34), and 83.3% versus 80.4% (P=0.42) after death-censoring in treatment and control arms according to trial assignment. Although infusion times varied substantially in the treatment arm (range 0-32.2 hours), duration of the dopamine infusion and all-cause graft failure exhibited an exposure-response relationship (hazard ratio, 0.96; 95% confidence interval [95% CI], 0.92 to 1.00, per hour). Cumulative frequency curves of graft survival and exposure time of the dopamine infusion indicated a maximum response rate at 7.10 hours (95% CI, 6.99 to 7.21), which almost coincided with the optimum infusion time for improvement of early graft function (7.05 hours; 95% CI, 6.92 to 7.18). Taking infusion time of 7.1 hours as threshold in subsequent graft survival analyses indicated a relevant benefit: Overall, 81.5% versus 68.5%; P=0.03; and 90.3% versus 80.2%; P=0.04 after death-censoring.

CONCLUSIONS

We failed to show a significant graft survival advantage on intention-to-treat. Dopamine infusion time was very short in a considerable number of donors assigned to treatment. Our finding of a significant, nonlinear exposure-response relationship disclosed a threshold value of the dopamine infusion time that may improve long-term kidney graft survival.

Donor antigen-specific regulatory T-cell function affects outcome in kidney transplant recipients

Chronic transplant dysfunction, a major impediment to long-term allograft survival, is caused by several factors including an ongoing alloimmune response termed chronic rejection. To define some of these factors further, we selected 107 patients mismatched to their donors from 623 patients transplanted at a single center. Patients were categorized according to their immunosuppressive treatment and further divided into those with stable or chronic allograft dysfunction. Donor human lymphocyte antigen allopeptide-specific T-cell lines were then generated from stable patients and those with biopsy-proven chronic allograft nephropathy. Increased amounts of CD4+CD25+ regulatory T cells (Tregs) and Treg-associated gene expression profiles were found in cell lines derived from the patients with stable compared with those with chronic allograft dysfunction. Furthermore, a higher percentage of Tregs was found in patients with stable graft function on tacrolimus-based compared with cyclosporine-based immunosuppression protocols. Patients with stable graft function had a significantly higher expression of interleukin (IL)-4 and IL-10, whereas the cytokines IL-2, IL-17, and interferon-γ were significantly higher in patients with allograft dysfunction in vitro. Thus, enhancing the operational role of naturally occurring donor-specific Tregs in allograft recipients by adjusting the immunosuppression protocol may be advantageous particularly for patients with ongoing chronic rejection.

Risk factors for Pneumocystis jiroveci pneumonia (PcP) in renal transplant recipients

BACKGROUND

Pneumocystis jiroveci pneumonia (PcP) is a potentially life-threatening complication in renal transplant recipients with increased reports during the past few years. Individual risk factors for susceptibility to PcP are incompletely understood.

METHODS

We retrospectively analysed 60 cases of confirmed PcP, diagnosed in six German transplant centres between 2004 and 2008, as well as 60 matched controls.

RESULTS

Compared with controls, PcP cases revealed the following significant differences: PcP cases had a poorer renal function (eGFR 31 vs. 42 mL/min in controls), more biopsy-proven rejections (18 vs. 5 patients), more frequent treatment with mycophenolate mofetil (53 vs. 44 patients) and less frequent treatment with interleukin-2 receptor antagonist (20 vs. 32 patients). According to centre policy, in those years, none of the patients or controls had received PcP prophylaxis after transplantation. Of the 60 patients with PcP, 30% developed the disease after the currently recommended duration of prophylactic treatment, 27% died in the course of the disease and 45% required treatment in the ICU.

CONCLUSIONS

Our case-control study reveals a novel risk profile for PcP. Renal transplant recipients with more pronounced renal insufficiency following rejection episodes and treated with intensified immunosuppression are at particular risk for PcP.

Effects of donor pretreatment with dopamine on graft function after kidney transplantation: a randomized controlled trial

CONTEXT

Kidney graft function after transplantation can be improved through pharmacological donor pretreatment to limit organ injury from cold preservation.

OBJECTIVE

To determine whether pretreatment of brain-dead donors with low-dose dopamine improves early graft function in human renal transplant recipients.

DESIGN, SETTING, AND PATIENTS

Randomized, open-label, multicenter, parallel-group trial of 264 deceased heart-beating donors and 487 subsequent renal transplants performed at 60 European centers between March 2004 and August 2007 (final follow-up, December 31, 2008). Eligible donors were stable under low-dose norepinephrine with a normal serum creatinine concentration on admission.

INTERVENTIONS

Donors were randomized to receive low-dose dopamine (4 mug/kg/min).

MAIN OUTCOME MEASURES

Dialysis requirement during first week after transplantation.

RESULTS

Dopamine was infused for a median of 344 minutes (IQR, 215 minutes). Dialysis was significantly reduced in recipients of a dopamine-treated graft. Fewer recipients in the treatment group needed multiple dialyses (56/227; 24.7%; 95% CI, 19.0%-30.3%; vs 92/260; 35.4%; 95% CI, 29.5%-41.2%; P = .01). The need for multiple dialyses posttransplant was associated with allograft failure after 3 years (HR, 3.61; 95% CI, 2.39-5.45; P < .001), whereas a single dialysis was not (HR, 0.67; 95% CI, 0.21-2.18; P = .51). Besides donor dopamine (OR, 0.54; 95% CI, 0.35-0.83; P = .005), cold ischemic time (OR, 1.07; 95% CI, 1.02-1.11 per hour; P = .001), donor age (OR, 1.03; 95% CI, 1.01-1.05 per year; P < .001), and recipient body weight (OR, 1.02; 95% CI, 1.01-1.04 per kg; P = .009) were independent explanatory variables in a multiple logistic regression model. Dopamine resulted in significant but clinically meaningless increases in the donor's systolic blood pressure (3.8 mm Hg; 95% CI, 0.7-6.9 mm Hg; P = .02) and urine production before surgical recovery of the kidneys (29 mL; 95% CI, 7-51 mL; P = .009) but had no influence on outcome.

CONCLUSION

Donor pretreatment with low-dose dopamine reduces the need for dialysis after kidney transplantation.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00115115.

[MRI after renal transplantation with dysfunctional allograft: are there typical diagnoses in the early and late postoperative phases?]

PURPOSE

The aim of this study was to evaluate the different MRI diagnoses in the early and late post-operative period after renal transplantation with dysfunctional allograft.

MATERIALS AND METHODS

Due to unknown transplant dysfunction, 49 patients (30-male, 19 female) received a total of 74 MRI studies. According to the date of examination all MRI studies were divided in an early (< or = 60 days, ETP) and a late post-transplant time period (> 60 days, LTP). All MRI studies were performed on 1.5 T MRI systems using a standardised imaging protocol consisting of a morphological (pre- and post-contrast enhanced T (1)- and T (2)-weighted TSE sequences), a vascular (contrast-enhanced 3D MRA) and a urographical part (Flash 3D sequences). Frequencies of diagnoses in ETP and LTP, and diagnoses within each transplant time period were analysed.

RESULTS

44/74 MRI studies were performed in ETP, 30/74 in LTP. In total 80 diagnoses were obtained: Renal artery stenosis (ETP, n = 21; LTP, n = 5), renal vein stenosis (ETP, n = 2), renal vein thrombosis (ETP, n = 2), renal perfusion defect (ETP, n = 11), rejection (ETP, n = 1; LTP, n = 2), abscess (ETP, n = 1), urinary outflow obstruction (LTP, n = 4), without MRI pathology (ETP, n = 11; LTP, n = 20). Renal artery stenosis was the most prevalent diagnosis in ETP, and a more frequent finding in ETP compared to LTP (p < 0.05). Renal perfusion defects were more frequent in ETP than in LTP (p < 0.05). In the ETP vascular diseases (34/49 diagnoses) were more frequent (p < 0.05) than uropathological diseases (0/49 diagnoses).

CONCLUSIONS

Our results indicate that vascular diseases are a more frequent occurrence in the early post-operative course after renal transplantation than uropathological diseases. However, a transplant follow-up MRI study needs to contain a morphological, vascular and functional imaging part to answer combined clinical questions.

Prospective age-matching in elderly kidney transplant recipients--a 5-year analysis of the Eurotransplant Senior Program

Renal transplantation faces challenges: the organ shortage resulting in extended waiting times and an aging population resulting in death with a functioning graft. The Eurotransplant Senior Program (ESP) allocates kidneys within a narrow geographic area from donors aged >/=65 years to recipients >/=65 years regardless of HLA. This analysis investigates the impact of the ESP on waiting time, graft and patient survival. The ESP group (n = 1406, old to old) was compared to two groups allocated via the Eurotransplant Kidney Allocation System (ETKAS) with either similar donor age (old to any [O/A], donor age >/=65, n = 446) or recipient age (any to old, [A/O], recipient age 60-64, n = 1687). All patients were transplanted between 1999 and 2004. Since initiation of the ESP (1999), availability of elderly donors doubled and waiting time for ESP patients decreased. Local allocation led to shorter cold ischemia time (11.9 vs. >17.0 h, p < 0.001) and less delayed graft function (DGF, ESP 29.7% vs. O/A 36.2%, p = 0.047) but 5-10% higher rejection rates. Graft and patient survival were not negatively affected by the ESP allocation when compared to the standard allocation. The ESP age matching of elderly donors and recipients is an effective allocation system for organs from elderly donors.

[Antiphospholipid antibody syndrome: a priori a contraindication to kidney transplantation?]

BACKGROUND

The antiphospholipid antibody syndrome (APLS) is characterised by the presence of antiphospholipid antibodies in association with thrombotic disorders of the arterial and/or venous system, spontaneous abortion and thrombocytopenia. Several studies have shown that end-stage renal disease patients with APLS are at extremely high risk for graft thrombosis and graft loss after kidney transplantation.

MATERIAL AND METHODS

We report on the treatment and clinical courses of 6 APLS renal transplant patients.

RESULTS

Of 3 patients treated with low-dose subcutaneous heparin two had early graft loss due to venous graft thrombosis; of those patients treated by systemic heparin (PTT goal 45-55 s) and followed by coumadin (INR 2.5-3.0) only one had early graft loss whereas 2 grafts are doing well 2 years post-transplant.

CONCLUSION

Our experience as well as recently published data suggest that kidney transplantation can be performed successfully in APLS patients if anticoagulation therapy is performed consistently. A general APL antibody screening prior to kidney transplantation does not seem to be justified at present. A prospective, randomised multicenter study is warranted to evaluate the management of these patients with respect to intensity, type and duration of anticoagulation therapy.

Effects of Pravastatin Treatment on Blood Pressure Regulation after Renal Transplantation

BACKGROUND/AIM

Hypertension is one of the main cardiovascular risk factors and has an impact also on long-term kidney graft survival. In addition to their lipid-lowering properties, it was shown that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors also have a blood pressure lowering effect. We examined whether treatment with a statin interferes with blood pressure regulation and antihypertensive treatment after renal transplantation.

METHODS

74 patients were treated with initially 20 mg of pravastatin daily immediately after kidney transplantation. This group was compared to a matched cohort of 76 patients without statin treatment. All patients received standard immunosuppressive triple therapy with ciclosporin A microemulsion together with an antiproliferative agent and prednisolone. Primary objective of this analysis was systolic and diastolic blood pressure regulation with and without pravastatin. Furthermore, graft function expressed as creatinine clearance and proteinuria, immunosuppressive regimen, and incidence of cardiovascular events and graft loss were recorded for 48 months.

RESULTS

The blood pressure regulation was comparable in both groups; however, to achieve this, significantly more antihypertensive drugs had to be used in the statin-treated patients as compared with the controls (2.9 vs. 2.2 agents at 48 months). A slightly higher ciclosporin A exposure of the statin-treated patients could have contributed to this observation. The graft function after 4 years was comparable between the groups (creatinine clearance 56.9 vs. 57.0 ml/min), and a trend of reduced proteinuria could be demonstrated after 4 years of statin treatment (0.4 vs. 0.9 g/day). The low-density lipoprotein cholesterol levels decreased as expected during treatment (3.1 vs. 3.7 mmol/l at 48 months), but the recommended target levels for patients with a high cardiovascular risk have not been reached. A trend towards lower incidences of acute rejection, chronic allograft nephropathy, and graft loss was noted in the statin-treated group. Adverse effects of statin treatment have not been observed.

CONCLUSION

Treatment with pravastatin at low to average dosages does not result in improved blood pressure regulation after kidney transplantation.

Efficacy and safety of preemptive anti-CMV therapy with valganciclovir after kidney transplantation

BACKGROUND

CMV infections still pose a potentially serious threat to kidney transplant recipients and have a significant impact on graft as well as patient survival. The antiviral agent valganciclovir (VGCV) has a greater bioavailability after oral administration than oral ganciclovir (GCV) and can be considered a substitute for GCV. The substance is approved in North America and Europe for anti-CMV prophylaxis after organ transplantation. In this pilot study, we examined if VGCV could also be administered in preemptive treatment of CMV infections.

METHODS

Twenty-eight renal transplant recipients suffering from 32 asymptomatic episodes of CMV infection were treated with VGCV and followed up. CMV infection was diagnosed by routine controls of pp65-antigenemia in pre-defined intervals. All patients received sequential quadruple immunosuppression. VGCV was given for up to 12 wk in a dosage adapted to renal graft function. Efficacy and safety parameters were monitored for 16 wk.

RESULTS

Twenty-seven episodes of CMV antigenemia, two patients progressing to CMV syndrome and three patients progressing to CMV disease were treated. Primary efficiency was 79%, Four patients relapsed and were treated with a second course resulting in serological recovery. Two patients did not respond to oral VCGV and were switched to another antiviral agent. Graft function remained stable during and after treatment. Serious side effects were seen in seven patients, four patients complained of diarrhea and gastrointestinal pain, three patients suffered from leucopenia, in one of these treatment had to be temporary paused. Fifty-nine percent of all episodes were treated in a completely ambulatory setting.

CONCLUSIONS

VGCV can be considered as an option also for preemptive treatment of CMV infections after renal transplantation. The antiviral potency seems to be adequate, potential side effects are comparable with IV GCV. Because of the improved pharmacokinetics of VGCV the substance can be used to abbreviate or even completely avoid in-hospital care of CMV infections.

Advanced renal insufficiency in a 34-year-old man with Lowe syndrome

Lowe syndrome, or oculocerebrorenal syndrome of Lowe (OCRL), is a rare X-chromosomal disorder characterized by renal dysfunction, congenital cataract, and, in the majority of cases, mental retardation. Although gradual loss of renal function has been seen in most patients, age of onset of deterioration in renal function and its severity and course over time in adult patients have not been documented in detail. We report a 34-year-old man with OCRL without histological changes in renal tissue at the ages of 5 and 8 years, whereas at the age of 29 years, focal and segmental glomerulosclerosis and tubular atrophy were found. During subsequent follow-up of 5 years, progressive loss of renal function occurred, and end-stage renal failure can be expected in a few years. Clinical diagnosis was strongly supported by detecting a nucleotide substitution (IVS19+1g-->a) in the evolutionarily strictly conserved splice consensus sequence of intron 19 of the OCRL1 gene, which may interfere with normal splicing. Clinical course, possible molecular consequences of this novel mutation, and correlation between genotype and phenotype are discussed.

L-arginine deficiency and supplementation in experimental acute renal failure and in human kidney transplantation

BACKGROUND

The "L-arginine paradox" refers to situations where L-arginine (L-Arg) supplementation stimulates nitric oxide (NO) synthesis, despite saturating intracellular concentrations. This paradox is frequently observed in acute renal failure (ARF). First, the effects of L-Arg on renal function of rats with ARF were studied. Based on the promising results from these initial studies, the second part of our study searched for a form of ARF in humans that could be studied easily under conditions with little variance and yet was linked with endothelial dysfunction. Thus, we investigated the effects of L-Arg supplementation immediately after kidney transplantation in 54 patients.

METHODS

In uranyl nitrate-induced ARF in rats the effects of L-Arg and L-NNA (inhibitor of nitric oxide synthase; NOS) on glomerular filtration rate (GFR), renal plasma flow (RPF), blood pressure (BP) and NOx (NO2- +NO3-) excretion were examined. Tissue L-Arg levels, NOS activities, immunodetection of NOS and superoxide dismutase (SOD), activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and xanthine oxidase, and nitrotyrosine immunoreactive protein (NT-IR) were determined and compared to sham operated animals. Secondly, in a randomized, double-blind study, the effects of L-Arg on GFR and RPF were investigated in 54 kidney transplant recipients, receiving IV L-Arg for three days. GFR and RPF were measured on days 1, 3, 5 and 10 by scintigraphy.

RESULTS

In experimental ARF, decreased RPF and GFR were associated with reduced tissue L-Arg levels, endothelial NOS-III expression, NO formation and NOx excretion. Reduction in GFR, RPF and NOx excretion were reversed upon administration of exogenous L-Arg. There also was a loss of Cu,Zn-SOD, a key enzyme against oxidative stress, and an elevation of NT-IR, an indicator of nitrosative stress and suggested marker for pathological actions of NO. However, NT-IR was not dependent on de novo NO synthesis and not related to the functional effects of l-Arg administration. In kidney transplant recipients receiving organs with a short cold ischemia time (CIT) and from young donors, that is, those with a higher likelihood of a functional endothelium, early administration of L-Arg improved renal function.

CONCLUSION

Both experimental and clinical data show that \L-Arg deficiency and endothelial dysfunction are pathomechanistically relevant in ARF. The data suggest a therapeutic potential for the administration of L-Arg in ARF and kidney transplantation, at least in patients receiving kidneys with shorter CIT and from younger donors.

Haemodynamic effects of valsartan in acute renal ischaemia/reperfusion injury

BACKGROUND

Acute deterioration of renal function is an important side-effect of angiotensin-converting enzyme (ACE) inhibitors, especially if accompanied by other nephrotoxic events. Angiotensin II receptor(1) blockers (ARB) are thought to have fewer side-effects on renal perfusion and function. We examined the effects of valsartan (VAL) on kidney function as well as the contribution of the nitric oxide (NO) system in a rat model of ischaemic acute renal failure (ARF).

METHODS

ARF was induced by 40 min of clamping of both renal arteries in female Sprague-Dawley rats. Renal haemodynamic and tubular parameters were determined during post-ischaemic infusion of vehicle, VAL, VAL and the NO-synthase substrate L-arginine, and VAL together with inhibition of NO synthases (NOS) by L-NMMA.

RESULTS

Clamping induced acute renal failure with marked decreases in glomerular filtration rate (GFR) and renal plasma flow (RPF) accompanied by a rise in renal vascular resistance (RVR) and fractional sodium excretion. Valsartan caused a slight but significant improvement of GFR and RPF without full recovery of renal function and caused a lowering of RVR and tubular sodium loss. L-arginine-co-administration had no additive beneficial effect. Valsartan-induced changes were not significantly depressed by unspecific inhibition of NOS.

CONCLUSIONS

Inhibition of the angiotensin II-receptor(1) diminishes the deleterious effects of ischaemia and reperfusion on glomerular function and on the renal microcirculation. An involvement of the NO system could not be demonstrated.

Hormonal changes in brain death and immune activation in the donor

Kidneys obtained from brain dead donors show inferior graft survival compared to living donation. The effects of brain death itself are thought to be partly responsible for these results. We, therefore, examined levels of catecholamines, the vasoconstricting hormones AT II, ET-1 and renin activity, pituitary hormones, and their correlation to pro-inflammatory cytokines and cytokine receptors. In 17 brain dead patients and 19 preoperative neurosurgical patients, these parameters were measured by HPLC, RIA and ELISA. Brain death resulted in massive increases in serum catecholamines, AT II and ET-1, as well as PRA, whereas thyroid and adrenal hormone levels remained unchanged. We found a significant correlation with rises in IL-6 and soluble TNF and IL-2 receptors as markers for the activation of immunological cascades. We concluded that these effects could be directly and indirectly responsible for the impaired organ perfusion and function observed in brain death.

Tacrolimus in acute renal failure: does L-arginine-infusion prevent changes in renal hemodynamics?

Nephrotoxicity is one of the main side effects of calcineurin-inhibitors. The influence of tacrolimus on the renal vasculature has not been well described. We have therefore examined the effects of tacrolimus on renal functional parameters as well as the contribution of the NO-system in a model of ischemic acute renal failure (ARF). Induction of ARF was achieved by clamping both renal arteries of female Sprague-Dawley rats. During the experiment, RBF, GFR, MAP, RVR and FENa were determined during infusion of vehicle, TAC, TAC and the NOS-activator L-arginine, and TAC and NOS-inhibition due to L-NMMA. TAC induced a significant rise in RVR with further decrease of RBF and GFR. Simultaneous L-arginine-infusion could reverse these effects during the infusion without complete restoration to preischemic levels. NOS-inhibition increased MAP and RBF without any effect on GFR. FENa did not differ significantly between the groups. Tacrolimus in the situation of ischemic acute renal failure causes vasoconstriction of pre- and postglomerular vessels with a further deterioration of renal function. L-arginine abolishes the functional deterioration, most likely due to increased NO-liberation.

Endotoxin-induced acute renal failure in the rat: effects of urodilatin and diltiazem on renal function

Acute renal failure (ARF) due to endotoxins is a common problem in clinical medicine. Endotoxins are released from the outer membrane of the gram-negative bacterial envelope and are composed of lipopolysaccharides (LPS). Although systemic hypotension often is present, LPS-induced ARF is characterized by marked intrarenal vasoconstriction. Both calcium channel blockers and natriuretic peptides are able to antagonize vasoconstricting signals and have been reported to exert beneficial effects in toxic and ischemic ARF: We investigated the effects of diltiazem (Dil, 300 micrograms/kg) or urodilatin (Uro, 40 micrograms/kg) or a combination of both (same doses) on renal function in early LPS-induced ARF: One hour after induction of ARF by i.v. injection of LPS glomerular filtration rate (GFR, clearance of fluorescence-marked inulin) was distinctly reduced to about 54% of basal values. In the following infusion period (60 min) a significant increase of GFR was observed with diltiazem (1.54 +/- 0.11 ml/min), urodilatin (1.60 +/- 0.10 ml/min) and the combination of both drugs (1.66 +/- 0.04 ml/min) compared to controls (1.17 +/- 0.08 ml/min). Combined administration did not cause additive effects. Also 60 and 120 minutes after stopping of drug infusion elevated GFR could be maintained in all experimental groups. Due to their vasorelaxing activity both Uro and Dil induced a decrease of mean arterial blood pressure in comparison with controls and revealed remarkable diuretic and natriuretic activity. In conclusion our results underline that marked intrarenal vasoconstriction in LPS-induced ARF can be antagonized by the well known relaxing potency of Uro and Dil towards vascular smooth muscle and mesangial cells. Both Uro and Dil were capable of improving suppressed renal function in the early phase of LPS-induced ARF in the rat as long as severe systemic hypotension is absent.

Effects of urodilatin and diltiazem on renal function in ischemic acute renal failure in the rat

In humans as well as in experimental models the hallmark of ischemic acute renal failure (ARF) is a profound diminution in glomerular filtration rate (GFR) and renal blood flow. Both calcium antagonists and a-ANP have been reported to exert beneficial effects in ischemic ARF. No data, however, exist about combined administration of the natriuretic peptide urodilatin and calcium channel blockers. We therefore investigated the effects of urodilatin (URO, 40 micrograms/kg/h, i.v.) and diltiazem (DIL, 300 micrograms/kg/h, i.v.) in the rat given immediately after clamping of both renal arteries for 40 min. Compared to controls (0.07 +/- 0.01) depressed GFR (ml/min/100 g) was clearly elevated with URO (0.16 +/- 0.03), DIL (0.13 +/- 0.03) and URO + DIL (0.14 +/- 0.02) after the ischemic lesion. After cessation of drug delivery the beneficial effects were blunted in the URO group, in contrast to the DIL and URO + DIL group, where GFR was significantly elevated compared to controls even 3 h after starting reperfusion. Besides that also urine flow, sodium excretion and blood pressure were examined. In conclusion both URO and DIL exert beneficial effects in ischemic ARF in the rat while infused. In contrast to URO DIL showed prolonged beneficial effects even after cessation of drug delivery. An additional effect of both drugs could not be observed.

Toxic acute renal failure in the rat: effects of diltiazem and urodilatin on renal function

Beneficial effects of natriuretic peptides have been reported in different models of acute renal failure (ARF). Calcium antagonists can also improve renal function, especially in ischemic models of ARF. The aim of our study was to investigate the effects of urodilatin and diltiazem alone and in combination in uranyl nitrate-induced toxic ARF in the rat. Three hours after induction of ARF glomerular filtration rate (GFR) was clearly diminished to about 50% compared to basal values. Intravenous infusion of diltiazem and urodilatin revealed a significant increase of GFR that even continued after cessation of drug delivery. Combined administration of urodilatin and diltiazem had no additional effect, probably due to a more pronounced fall in blood pressure in this group. Besides their vasorelaxing and blood pressure lowering effects both drugs also revealed diuretic activity. In conclusion both urodilatin and diltiazem are able to elevate GFR in the early phase of toxic ARF in the rat.