Super High Flux Hemodialysis at High Dialysate Flows: An Ex Vivo Assessment

Background and objectives

The removal of cytokines by standard hemofiltration is limited. Super high flux membranes may significantly improve removal even when used in dialysis mode. We sought to measure cytokine clearance using a large surface super high-flux membrane and a standard hemodialysis setting.

Setting

ICU laboratory of a tertiary institution.

Subjects

Six healthy volunteers.

Methods

Blood form healthy volunteers was incubated for 4 hours with E. coli endotoxin to stimulate cytokine production. Cytokine containing blood was then circulated through a dialysis circuit at 3 different dialysate flow rates. Blood and dialysate were sampled for cytokine and albumin measurements and calculation of clearances.

Results

Super high-flux dialysis achieved high median cytokine clearances (IL-1 clearance of 106 ml/min, IL-6 clearance of 66.8 ml/min, IL-8 clearance of 61.7 ml/min and TNF clearance of 36.1 ml/min). Increasing dialysate flow rate from 300 to 500 ml/min did not significantly increase cytokine clearances. Albumin clearances however were between 2.7 and 5.4 ml/min.

Conclusions

Cytokine dialysis is feasible at high dialysate flow rates yielding high cytokine clearances. Albumin loss, however, is appreciable and may require separate supplementation in the clinical setting.

High frequency of valganciclovir underdosing for cytomegalovirus prophylaxis after renal transplantation

Background

The correct valganciclovir dose for cytomegalovirus (CMV) prophylaxis depends on renal function estimated by the Cockcroft–Gault (CG) estimated creatinine clearance (CG-CrCl) formula. Patients with delayed or rapidly changing graft function after transplantation (tx) will need dose adjustments.

Methods

We performed a retrospective investigation of valganciclovir dosing in renal transplant patients receiving CMV prophylaxis between August 2003 and August 2011, and analysed valganciclovir dosing, CG-CrCl, CMV viraemia (CMV-PCR <750 copies/mL), leucopenia (<3500/µL) and neutropenia (<1500/µL) in the first year post-transplant. On Days 30 and 60 post-transplant, dosing pattern in relation to estimated creatinine clearance was analysed regarding CMV viraemia, leucopenia and neutropenia.

Results

Six hundred and thirty-five patients received valganciclovir prophylaxis that lasted 129 ± 68 days with a mean dose of 248 ± 152 mg/day of whom 112/635 (17.7%) developed CMV viraemia, 166/635 (26.1%) leucopenia and 48/635 (7.6%) neutropenia. CMV resistance within 1 year post-transplant was detected in three patients. Only 137/609 (22.6%) patients received the recommended dose, while n = 426 (70.3%) were underdosed and n = 43 (7.1%) were overdosed at Day 30 post-tx. Risk factors for CMV viraemia were donor positive D (+)/receptor negative R (−) status and short prophylaxis duration, but not low valganciclovir dose. Risk factors for developing leucopenia were D+/R− status and low renal function. No significant differences in dosing frequency were observed in patients developing neutropenia or not (P = 0.584).

Conclusion

Most patients do not receive the recommended valganciclovir dose. Despite obvious underdosing in a large proportion of patients, effective prophylaxis was maintained and it was not associated as a risk factor for CMV viraemia or leucopenia.

IL-17 Expression in the Time Course of Acute Anti-Thy1 Glomerulonephritis

BACKGROUND

Interleukin-17 (IL-17) is a new pro-inflammatory cytokine involved in immune response and inflammatory disease. The main source of IL-17 is a subset of CD4+ T-helper cells, but is also secreted by non-immune cells. The present study analyzes expression of IL-17 in the time course of acute anti-thy1 glomerulonephritis and the role of IL-17 as a potential link between inflammation and fibrosis.

METHODS

Anti-thy1 glomerulonephritis was induced into male Wistar rats by OX-7 antibody injection. After that, samples were taken on days 1, 5, 10 (matrix expansion phase), 15 and 20 (resolution phase). PBS-injected animals served as controls. Proteinuria and histological matrixes score served as the main markers for disease severity. In in vitro experiments, NRK-52E cells were used. For cytokine expressions, mRNA and protein levels were analyzed by utilizing RT-PCR, in situ hybridization and immunofluorescence.

RESULTS

Highest IL-17 mRNA-expression (6.50-fold vs. con; p<0.05) was found on day 5 after induction of anti-thy1 glomerulonephritis along the maximum levels of proteinuria (113 ± 13 mg/d; p<0.001), histological glomerular-matrix accumulation (82%; p<0.001) and TGF-β1 (2.2-fold; p<0.05), IL-6 mRNA expression (36-fold; p<0.05). IL-17 protein expression co-localized with the endothelial cell marker PECAM in immunofluorescence. In NRK-52E cells, co-administration of TGF-β1 and IL-6 synergistically up-regulated IL-17 mRNA 4986-fold (p<0.001).

CONCLUSIONS

The pro-inflammatory cytokine IL-17 is up-regulated in endothelial cells during the time course of acute anti-thy1 glomerulonephritis. In vitro, NRK-52E cells secrete IL-17 under pro-fibrotic and pro-inflammatory conditions.

The inferior impact of antibody-mediated rejection on the clinical outcome of kidney allografts that develop de novo thrombotic microangiopathy

BACKGROUND

Antibody-mediated rejection (AMR) can induce and develop thrombotic microangiopathy (TMA) in renal allografts. A definitive AMR (dAMR) co-presents three diagnostic features. A suspicious AMR (sAMR) is designated when one of the three features is missing.

METHODS

Thirty-two TMA cases overlapping with AMR (AMR+ TMA) were studied, which involved 14 cases of sAMR+ TMA and 18 cases of dAMR+ TMA. Thirty TMA cases free of AMR features (AMR- TMA) were enrolled as control group.

RESULTS

The ratio of complete response to treatment was similar between AMR- TMA and AMR+ TMA group (23.3% vs. 12.5%, p = 0.33), or between sAMR+ TMA and dAMR+ TMA group (14.3% vs. 11.1%, p = 0.79). At eight yr post-transplantation, the death-censored graft survival (DCGS) rate of AMR- TMA group was 62.8%, which was significantly higher than 28.0% of AMR+ TMA group (p = 0.01), but similar between sAMR+ TMA and dAMR+ TMA group (30.0% vs. 26.7%, p = 0.92). Overall, the intimal arteritis and the broad HLA (Human leukocyte antigens) mismatches were closely associated with over time renal allograft failure.

CONCLUSION

The AMR+ TMA has inferior long-term graft survival, but grafts with sAMR+ TMA or dAMR+ TMA have similar characteristics and clinical courses.

No relevant pharmacokinetic interaction between pantoprazole and mycophenolate in renal transplant patients: a randomized crossover study

AIMS

Mycophenolic acid (MPA) suppresses lymphocyte proliferation through inosine monophosphate dehydrogenase (IMPDH) inhibition. Two formulations have been approved: mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS). Pantoprazole (PAN) inhibits gastric acid secretion, which may alter MPA exposure. Data from healthy volunteers suggest a significant drug-drug interaction (DDA) between pantoprazole and MPA. In transplant patients, a decreased MPA area under the concentration-time curve (AUC) may lead to higher IMPDH activity, which may lead to higher acute rejection risk. Therefore this DDA was evaluated in renal transplant patients under maintenance immunosuppressive therapy.

METHODS

In this single-centre, open, randomized, four-sequence, four-treatment crossover study, the influence of PAN 40 mg on MPA pharmacokinetics such as (dose-adjusted) AUC0-12 h (dAUC) was analysed in 20 renal transplant patients (>6 months post-transplantation) receiving MMF (1-2 g day(-1) ) and EC-MPS in combination with ciclosporin. The major metabolite MPA glucuronide (MPAG) and the IMPDH activity were also examined.

RESULTS

MMF + PAN intake led to a lowest mean dAUC for MPA of 41.46 ng h ml(-1) mg(-1) [95% confidence interval (CI) 32.38, 50.54], while MPA exposure was highest for EC-MPS + PAN [dAUC: 46.30 ng h ml(-1) mg(-1) (95% CI 37.11, 55.49)]. Differences in dAUC and dose-adjusted maximum concentration (dCmax) were not significant. Only for MMF [dAUC: 41.46 ng h ml(-1) mg(-1) (95% CI 32.38, 50.54)] and EC-MPS [dAUC: 43.39 ng h ml(-1) mg(-1) (95% CI 33.44, 53.34)] bioequivalence was established for dAUC [geometric mean ratio: 101.25% (90% CI 84.60, 121.17)]. Simultaneous EC-MPS + PAN intake led to an earlier time to Cmax (tmax) [median: 2.0 h (min-max: 0.5-10.0)] than EC-MPS intake alone [3 h (1.5-12.0); P = 0.037]. Tmax was not affected for MMF [1.0 h (0.5-5.0)] ± pantoprazole [1.0 h (0.5-6.0), P = 0.928). No impact on MPAG pharmacokinetics or IMPDH activity was found.

CONCLUSION

Pantoprazole influences EC-MPS and MMF pharmacokinetics but as it had no impact on MPA pharmacodynamics, the immunosuppressive effect of the drug was not impaired.

Designation of T-cell-mediated rejection type Ib and IIa reflects the type of rejection rather than the severity in the Banff classification

OBJECTIVES

Whether T-cell-mediated rejection Banff classification type Ib (severe tubulointerstitial rejection) and type IIa (mild vascular rejection) are associated with responses to antirejection therapy and long-term graft survival are unclear.

MATERIALS AND METHODS

One hundred ten patients were enrolled who had at least 1 episode of T-cell-mediated rejection and whose highest T-cell-mediated rejection severity was T-cell-mediated rejection type Ib or IIa.

RESULTS

T-cell-mediated rejection Ib occurred significantly later than T-cell-mediated rejection IIa (P < .001). The proportion of partial/no response to antirejection therapy was comparable between the 2 groups (P = .83). Up to 8-year posttransplant, death-censored graft survival rate of the T-cell-mediated rejection Ib group was similar to that of the T-cell-mediated rejection IIa group (P = .51). Early T-cell-mediated rejection IIa had a statistically higher death-censored graft survival rate than did late T-cell-mediated rejection IIa (P < .001), while no significant difference in the death-censored graft survival was found between early and late T-cell-mediated rejection Ib (P = .11) or between early T-cell-mediated rejection Ib and early T-cell-mediated rejection IIa (P = .11) or between late T-cell-mediated rejection Ib and late T-cell-mediated rejection IIa (P = .07). Furthermore, the T-cell-mediated rejection IIa with isolated v1 lesion (v1, i0-1, t0-1) showed a similar death-censored graft survival rate compared to T-cell-mediated rejection IIa with intensive tubulointerstitial inflammation (v1, i2-3, t2-3). The timing of rejection, graft number, the number of indicated biopsies and the presence of ci/ct lesions were associated with long-term graft loss.

CONCLUSIONS

The designation of T-cell-mediated rejection type Ib and IIa reflects the different type rather than the distinct severity of rejection and has no independent prognostic significance.

Tubular von Hippel-Lindau knockout protects against rhabdomyolysis-induced AKI

Renal hypoxia occurs in AKI of various etiologies, but adaptation to hypoxia, mediated by hypoxia-inducible factor (HIF), is incomplete in these conditions. Preconditional HIF activation protects against renal ischemia-reperfusion injury, yet the mechanisms involved are largely unknown, and HIF-mediated renoprotection has not been examined in other causes of AKI. Here, we show that selective activation of HIF in renal tubules, through Pax8-rtTA-based inducible knockout of von Hippel-Lindau protein (VHL-KO), protects from rhabdomyolysis-induced AKI. In this model, HIF activation correlated inversely with tubular injury. Specifically, VHL deletion attenuated the increased levels of serum creatinine/urea, caspase-3 protein, and tubular necrosis induced by rhabdomyolysis in wild-type mice. Moreover, HIF activation in nephron segments at risk for injury occurred only in VHL-KO animals. At day 1 after rhabdomyolysis, when tubular injury may be reversible, the HIF-mediated renoprotection in VHL-KO mice was associated with activated glycolysis, cellular glucose uptake and utilization, autophagy, vasodilation, and proton removal, as demonstrated by quantitative PCR, pathway enrichment analysis, and immunohistochemistry. In conclusion, a HIF-mediated shift toward improved energy supply may protect against acute tubular injury in various forms of AKI.

Influence of Everolimus on Steady-State Pharmacokinetics of Cyclosporine in Maintenance Renal Transplant Patients

To investigate possible interactions of the novel immunosuppressant everolimus with cyclosporine, a multicenter, randomized, double-blind, placebo-controlled, dose-escalating phase I study was performed. Everolimus regimens (0.75-10 mg/d) were administered for 28 days to stable renal allograft recipients receiving the microemulsion form of cyclosporine. Steady-state cyclosporine profiles were assessed at baseline on day 0 (cyclosporine alone) and on day 21 with everolimus on steady state. By day 21, mean dose-normalized cyclosporine AUC0-12 increased by 15% in patients receiving placebo. In everolimus-treated patients, mean increases in cyclosporine AUC0-12 ranged from 7% to 43%, which were not significantly different across all dosing cohorts including placebo. Linear regression of everolimus AUC on day 21 versus the increase in cyclosporine AUC0-12 yielded a slope not significantly different from a horizontal line (P = ns). In conclusion, these results suggest that steady-state everolimus exposure over the wide range assessed in this study did not affect steady-state cyclosporine pharmacokinetics.

Pharmacokinetics of aliskiren in patients with end-stage renal disease undergoing haemodialysis

BACKGROUND AND OBJECTIVES

Aliskiren represents a novel class of orally active renin inhibitors. This study analyses the pharmacokinetics, tolerability and safety of single-dose aliskiren inpatients with end-stage renal disease (ESRD) undergoing haemodialysis.

METHODS

Six ESRD patients and six matched healthy volunteers were enrolled in an open-label, parallel-group, single-sequence study. The ESRD patients underwent two treatment periods where 300 mg of aliskiren was administered 48 or 1 h before a standardized haemodialysis session (4 h, 1.4 m(2) high-flux filter, blood flow 300 mL/min, dialysate flow 500 mL/min). Washout was >10 days between both periods. Blood and dialysis samples were taken for up to 96 h postdose to determine aliskiren concentrations.

RESULTS

Compared with the healthy subjects (1681 ± 1034 ng·h/mL), the area under the plasma concentration-time curve (AUC) from time zero to infinity was 61% (haemodialysis at 48 h) and 41% (haemodialysis at 1 h) higher in ESRD patients receiving single-dose aliskiren 300 mg. The maximum (peak) plasma drug concentration (481 ± 497 ng/mL in healthy subjects) was 17% higher (haemodialysis at 48 h) and 16% lower (haemodialysis at 1 h). In both treatment periods, dialysis clearance was below 2% of oral clearance and the mean fraction eliminated from circulation was 10 and 12% in period 1 and 2, respectively. Drug AUCs were similar in ESRD patients receiving aliskiren 1 or 48 h before dialysis. No severe adverse events occurred.

CONCLUSION

The exposure of aliskiren is moderately higher in ESRD patients. Only a minor portion is removed by a typical haemodialysis session. Aliskiren exposure is not significantly affected by intermittent haemodialysis, suggesting that no dose adjustment is necessary in this population.

An evaluation of sirolimus in renal transplantation

INTRODUCTION

Sirolimus is a powerful antiproliferative immunosuppressive drug approved for the prevention of kidney allograft rejection. By its unique mechanism of action, sirolimus provides a multitude of clinical potential and has been used effectively in different drug combinations. Extensive experience has been gained regarding the best timing of its application, side effect profile and potential benefits and limitations compared with other immunosuppressive drugs.

AREAS COVERED

The authors evaluate the recent experience with sirolimus in kidney transplantation. Pivotal randomized controlled trials were used to provide an overview with special attention to pharmacokinetic and dynamic aspects of sirolimus, its current clinical use as well as perspectives for its future role.

EXPERT OPINION

Sirolimus enriches the possibilities of immunosuppressive therapies after renal transplantation. Beneficial effects toward kidney function by allowing CNI sparing, lower incidence of malignancies and less viral infections have been suggested. Sirolimus should be used cautiously in de novo patients for reasons of wound healing. An early conversion to a sirolimus-based CNI-free regimen has shown promising results, whereas late conversion is more challenging. Finally, sirolimus-associated side effects are causing tolerability concerns and frequent discontinuations. Future research should aim to better define the therapeutic window and those patients most likely to benefit.

Impact of biological gender and soluble guanylate cyclase stimulation on renal recovery after relief of unilateral ureteral obstruction

PURPOSE

Gender difference and nitric oxide deficiency contribute to the progression of many chronic kidney diseases. In a model of unilateral ureteral obstruction relief we analyzed the impact of biological gender and nitric oxide/cyclic guanosine monophosphate signaling stimulation on renal disease severity and restoration.

MATERIALS AND METHODS

Female and male rats underwent sham surgery or unilateral ureteral obstruction. After 5-day unilateral ureteral obstruction female and male rats were assigned to obstruction relief alone or obstruction relief plus 7-day treatment with the soluble guanylate cyclase stimulator BAY 41-8543.

RESULTS

Compared to male rats with obstruction relief renal disease was less severe in female rats, which had significantly less tubulointerstitial matrix accumulation and tubular atrophy. In each gender group α1 and β1-soluble guanylate cyclase was comparably and significantly increased but female rats produced significantly more cyclic guanosine monophosphate after treatment with the soluble guanylate cyclase stimulator. In each group BAY 41-8543 treatment was associated with significant amelioration of renal matrix protein expansion, macrophage infiltration, tubular apoptosis and atrophy.

CONCLUSIONS

Female gender is protective for unilateral ureteral obstruction relief. This was linked to higher sensitivity of the soluble guanylate cyclase enzyme and cyclic guanosine monophosphate production in response to BAY 41-8543. In these female and male rats enhancing the signaling of nitric oxide/cyclic guanosine monophosphate with BAY 41-8543 significantly accelerated the restoration of renal architecture after obstruction relief and largely ameliorated the differences in disease severity due to the gender disparity.

Does endothelin B receptor deficiency ameliorate the induction of peritoneal fibrosis in experimental peritoneal dialysis?

BACKGROUND

Peritoneal fibrosis is a serious complication of peritoneal dialysis (PD); however, the mechanisms are poorly understood. The endothelin system exhibits potent pro-fibrotic properties and is known to be stimulated in peritoneal fibrosis. Thus, our study aimed at elucidating the impact of the endothelin B (ETB) receptor on peritoneal membrane thickening by means of an ETB-deficient rat model (ETB(-)(/)(-)) in experimental PD.

METHODS

Wild-type (WT) and ETB(-/-) rats were randomly allocated to four groups (each group n = 10): (i) WT Sham, (ii) WT PD, (iii) ETB(-/-) Sham and (iv) ETB(-/-) PD. All animals underwent surgical implantation of a port for intraperitoneal administration and 1 week of habituation to the procedure by administration of 2 ml of saline once daily. Afterwards, all animals were switched to 12 weeks of 15 ml of saline (Sham groups) or commercially available PD fluid containing 3.86% glucose (PD groups) administered twice daily. Afterwards, animals were sacrificed, and samples from visceral as well as parietal peritoneum were obtained. The samples were stained with Sirius-Red, and at 10 different sites per sample, peritoneal membrane thickness was measured using computer-aided histomorphometry devices.

RESULTS

Mean peritoneal membrane thickness was increased by PD in both WT and ETB(-/-) rats versus respective Sham controls (WT Sham: 22.3 +/- 0.7 microm/ETB Sham: 22.3 +/- 0.9 microm versus WT PD: 26.5 +/- 1.5 microm/ETB PD: 28.7 +/- 1.2 microm; P < 0.05, respectively). However, no difference in peritoneal membrane thickness was detected between WT PD and ETB(-/-) PD groups.

CONCLUSION

Our study demonstrates that PD increases peritoneal membrane thickness in a rat model, but deficiency of the ETB receptor has no detectable impact on this process.

Inflammation in renal transplantation

BACKGROUND AND OBJECTIVES

Renal transplant recipients experience premature cardiovascular disease and death. The association of inflammation, all-cause mortality, and cardiovascular events in renal transplant recipients has not been examined in a large prospective controlled trial.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

ALERT was a randomized, double-blind, placebo-controlled study of the effect of fluvastatin on cardiovascular and renal outcomes in 2102 renal transplant recipients. Patients initially randomized to fluvastatin or placebo in the 5- to 6-yr trial were offered open-label fluvastatin in a 2-yr extension to the original study. The association between inflammation markers, high-sensitivity C-reactive protein (hsCRP), and IL-6 on cardiovascular events and all-cause mortality was investigated.

RESULTS

The baseline IL-6 value was 2.9 +/- 1.9 pg/ml (n = 1751) and that of hsCRP was 3.8 +/- 6.7 mg/L (n = 1910). After adjustment for baseline values for established risk factors, the hazard ratios for a major cardiac event and all-cause mortality for IL-6 were 1.08 [95% confidence interval (CI), 1.01 to 1.15, P = 0.018] and 1.11 (95% CI, 1.05 to 1.18, P < 0.001), respectively. The adjusted hazard ratio for hsCRP for a cardiovascular event was 1.10 (95% CI, 1.01 to 1.20, P = 0.027) and for all-cause mortality was 1.15 (95% CI, 1.06 to 1.1.25, P = 0.049).

CONCLUSIONS

The inflammation markers IL-6 and hsCRP are independently associated with major cardiovascular events and all-cause mortality in renal transplant recipients.

Pharmacodynamic evaluation of the first dose of mycophenolate mofetil before kidney transplantation

BACKGROUND AND OBJECTIVES

The effect of mycophenolate mofetil (MMF) on T cell function has not been evaluated in patients undergoing kidney transplantation. The aim of this study was to assess the effect of 1g of MMF on T cell function, that is, intralymphocyte cytokine expression, T cell activation (CD25 and CD71), and T cell proliferation, as well as inosine monophosphate dehydrogenase (IMPDH) activity, to better understand the relationship between pharmacokinetic and pharmacodynamic markers in patients receiving the first dose of MMF before kidney transplantation.

PATIENTS

Twenty-four patients undergoing a kidney transplantation from a living donor were enrolled in this study.

RESULTS

Compared with baseline (before MMF intake), T cell proliferation (93%), IMPDH activity (74%), CD25 (46%), and CD71 (50%) expression significantly decreased during the first hour after MMF intake, in parallel to the rise in MPA concentration. Thereafter, all pharmacodynamic markers, except IMPDH activity, returned back to baseline level. There was a complex inverse relationship between pharmacokinetic and pharmacodynamic markers. The inhibition of T cell proliferation was highly correlated to IMPDH activity, but also to T cell activation markers.

CONCLUSION

The administration of MMF to patients is associated not only with a dramatic decrease in both T cell proliferation and IMPDH activity, but also with in a decrease in CD25 and CD71 expression.

Outcomes of transplanting deceased-donor kidneys between elderly donors and recipients

Rate of acceptance of deceased-donor kidneys decreases with donor age despite the growing number of aged transplant candidates on the waiting list. In the Eurotransplant Senior Program, HLA-unmatched kidneys from deceased donors aged > or = 65 yr are transplanted regionally into recipients aged > or = 65 yr. Because we have become more willing to accept kidneys from donors aged > or = 75 yr than previous years, we performed a retrospective analysis of this subgroup. Kidneys were accepted from donors aged > or = 75 yr provided a normal creatinine on admission to the hospital, a Cockcroft-Gault creatinine clearance > 80 ml/min, and an absence of comorbidities. We compared outcomes of kidneys from donors aged > or = 75 yr with both younger-donor kidneys transplanted in the Eurotransplant Senior Program and with younger-donor HLA-matched kidneys transplanted into recipients > or = 60 yr. There were no differences in 5-yr graft and patient survival or rate of delayed graft function between groups. Graft function, measured by creatinine and creatinine clearance, differed without pattern at only three of 12 time points during 5 yr of follow-up. In conclusion, our data suggest that kidneys from deceased donors aged > or = 75 yr can be transplanted safely into recipients aged > or = 65 yr if similar donor criteria and local allocation practices are used.

Cross-over kidney transplantation with simultaneous laparoscopic living donor nephrectomy: initial experience

With cross-over living donor kidney transplantation, immunologic incompatibilities within the original donor/recipient pair can be overcome. As minimal invasive techniques for organ recovery are increasingly applied, this should also be performed in a cross-over kidney transplantation. We present the first report of a successful simultaneous laparoscopic kidney recovery for cross-over kidney transplantation as well as a review of the international practice of cross-over kidney transplantation in the context of national laws. Cross-over kidney transplantation should be encouraged. A databank on pairs willing to participate in organ exchange programs should be created.

Hemodialysis membrane with a high-molecular-weight cutoff and cytokine levels in sepsis complicated by acute renal failure: a phase 1 randomized trial

BACKGROUND

Sepsis is the leading cause of acute renal failure. Intermittent hemodialysis (IHD) is a common treatment for patients with acute renal failure. However, standard hemodialysis membranes achieve only little diffusive removal of circulating cytokines. Modified membranes may enable both successful IHD treatment and simultaneous diffusive cytokine removal.

STUDY DESIGN

Double-blind, crossover, randomized, controlled, phase 1 trial.

SETTING & PARTICIPANTS

Tertiary intensive care unit. 10 septic patients with acute renal failure according to RIFLE class F.

INTERVENTION

Each patient was treated with 4 hours of high-cutoff (HCO)-IHD and 4 hours of high-flux (HF)-IHD.

OUTCOMES & MEASUREMENTS

We chose relative change in plasma interleukin 6 (IL-6) concentrations from baseline to 4 hours as the primary outcome for effective cytokine removal. We measured plasma and effluent concentrations of cytokines (IL-6, IL-8, IL-10, and IL-18) and albumin.

RESULTS

Median age was 53 years (25(th) to 75(th) percentiles, 43 to 71 years). Both treatments achieved equal control of uremia. Four hours of HCO-IHD accomplished a greater decrease in plasma IL-6 levels (-30.3%) than 4 hours of HF-IHD (1.1%; P = 0.05). HCO-IHD, but not HF-IHD, achieved substantial diffusive clearance of several cytokines (IL-6, 14.1 mL/min; IL-8, 75.2 mL/min; and IL-10, 25.5 mL/min). Such clearance also was associated with greater relative decreases in plasma IL-8 and IL-10 levels in favor of HCO-IHD (P = 0.02, P = 0.04). We found significantly greater relative changes from prefilter to postfilter plasma IL-6, IL-8, and IL-10 values in favor of HCO-IHD (P = 0.02, P = 0.01, P < 0.01). During HCO-IHD, cumulative albumin loss into the effluent was 7.7 g (25(th) to 75(th) percentiles, 4.8 to 19.6) versus less than 1.0 g for HF-IHD (P < 0.01).

LIMITATIONS

Small phase 1 trial.

CONCLUSION

In septic patients with acute renal failure, HCO-IHD achieved simultaneous uremic control and diffusive cytokine clearances and a greater relative decrease in plasma cytokine concentrations than standard HF-IHD.

Reduced-exposure cyclosporine is safe and efficacious in de novo renal transplant recipients treated with enteric-coated mycophenolic acid and basiliximab

BACKGROUND

The lower limit of exposure to calcineurin inhibitors has not yet been established in de novo renal transplant patients receiving mycophenolic acid therapy with basiliximab.

METHODS

A 12-month, multicenter, randomized, open-label trial was carried out in which de novo renal transplant patients received enteric-coated mycophenolate sodium, cyclosporine microemulsion, steroids and basiliximab. Patients were randomized to receive standard-exposure (n = 45) or reduced-exposure (n = 44) cyclosporine, based on differing C2 target ranges, after the first month post-transplant.

RESULTS

Cyclosporine exposure gradually increased over the first month and was lower than previously recommended. Mean calculated creatinine clearance (primary end-point) was similar in the standard-exposure and reduced-exposure groups at month 6 (55.3+/-3.2 ml/min and 61.5+/-3.7 ml/min respectively, n.s.). There were 4 deaths but no death-censored graft losses, resulting in 95.5% patient and graft survival at one year in both groups. At 6 and 12 months, the incidence of biopsy-proven acute rejection was 17.8% and 17.8% in the standard-exposure group, and 13.6% and 15.9% in the reduced-exposure group. Adverse events were similar between treatment groups. Exploratory analyses could not identify a lower limit for the optimal CsA exposure range, but results suggested that high exposure at one year was associated with deteriorating renal function.

CONCLUSIONS

These results indicate that enteric-coated mycophenolate sodium with reduced-exposure cyclosporine, steroids and basiliximab induction has an excellent therapeutic effect and is safe in de novo kidney transplant recipients. Lower C2 targets than previously recommended, particularly early post-transplant, do not appear to be associated with compromised efficacy.

Use of proliferation signal inhibitors in the management of post-transplant malignancies--clinical guidance

Increasing success in renal transplantation and longer patient survival has meant that post-transplant malignancies are having an increasing impact on long-term graft and patient survival. Choice of the immunosuppressive agents provides one of the controllable risk factors for the development of malignancies in this population. Calcineurin inhibitors (CNIs) are associated with an increased incidence of cancers, whereas the proliferation signal inhibitors (PSIs), everolimus and sirolimus have demonstrated anti-oncogenic effects in pre-clinical models and are currently being investigated as anti-cancer agents in clinical trials. There is increasing evidence demonstrating a lower incidence of post-transplant malignancies in renal transplant recipients receiving PSI-based immunosuppression compared with those receiving CNIs. Conversion from CNIs to PSIs has been shown to lead to the regression of Kaposi's sarcoma in renal transplant recipients and is now part of accepted standard care for this tumour in this setting. The anti-cancer properties of PSI-based regimens have the potential to combine the dual benefits of immunosuppression without the use of CNIs and the direct anti-oncogenic effects through their inhibition of the mammalian target of rapamycin (mTOR) signalling pathway. In the absence of formal clinical trial evidence on the best way to use PSIs in this setting, a workshop was held to provide practical guidance on immunosuppressive strategies in the context of malignancy, given the current state of knowledge.

Conversion From Mycophenolate Mofetil to Enteric-Coated Mycophenolate Sodium in Maintenance Renal Transplant Recipients Receiving Tacrolimus: Clinical, Pharmacokinetic, and Pharmacodynamic Outcomes

BACKGROUND

Mycophenolic acid (MPA) pharmacokinetics using the mycophenolate mofetil (MMF) formulation are known to differ between patients receiving tacrolimus or cyclosporine, but only limited data exist concerning concomitant use of tacrolimus and enteric-coated mycophenolate sodium (EC-MPS).

METHODS

In this six-month, multicenter, open-label, single-arm trial, 63 maintenance renal transplant patients receiving tacrolimus were converted from mycophenolate mofetil (MMF) to EC-MPS.

RESULTS

MPA concentration-time profiles in 21 patients showed that MPA exposure was similar with MMF or EC-MPS (mean area under the curve 39.9+/-11.6 microg x h/mL versus 43.7+/-17.4 microg x h/mL at day 14 post-conversion). Median time to peak concentration was 0.5 hr with MMF and 1.5 hr with EC-MPS. Inosine monophosphate dehydrogenase (IMPDH) activity was almost identical: area under the enzyme activity time curve (AEC) was 124.2+/-32.0 nmol x h/mg prot/h with MMF and 130.3+/-36.6 nmol x h/mg prot/h with EC-MPS at 14 days post-conversion; average daytime IMPDH activity was 10.3+/-2.7 nmol/h/mg protein and 10.9+/-2.7 nmol/h/mg protein, respectively. Maximal daytime inhibition of IMPDH activity was 67% with MMF and 62% with EC-MPS at day 14. One patient (1.6%) experienced mild biopsy-proven acute rejection. No graft losses or deaths occurred. Renal function remained stable (mean calculated creatinine clearance 70.6+/-26.8 mL/min with MMF and 68.8+/-25.4 mL/min six months post-conversion). Adverse events or infections with a suspected relation to EC-MPS occurred in 12 patients (19%). Four patients discontinued EC-MPS due to adverse events or infections.

CONCLUSIONS

MMF and EC-MPS are associated with similar MPA exposure and equivalent pharmacodynamic effect. Conversion of tacrolimus-treated maintenance renal transplant patients from MMF to EC-MPS is safe and well-tolerated and does not compromise therapeutic efficacy.

Long-term safety and efficacy after conversion of maintenance renal transplant recipients from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPA, myfortic)

AIM

A 12-month multicenter, double-blind trial in which maintenance renal transplant patients were randomized to remain on mycophenolate mofetil (MMF) or convert to enteric-coated mycophenolate sodium (EC-MPS, myfortic) has demonstrated that conversion from MMF to EC-MPS is safe. Patients completing the study were invited to enter an open-label extension. Upon entry to the extension, patients who had received MMF during the randomized phase were converted to EC-MPS ("newly-exposed EC-MPS" group) and were monitored separately from those who had been randomized to EC-MPS ("long-term EC-MPS" group). The aim of the extension study was to collect long-term safety and efficacy data on EC-MPS, and to confirm the safety of conversion from MMF to EC-MPS in a larger patient population.

METHODS

All patients received EC-MPS 720 mg b.i.d. with cyclosporine microemulsion and corticosteroids per local practice. Data derived from the analysis of the first 24 months of the extension phase are presented.

RESULTS

Of the 297 patients who completed the core study, 260 (88%) entered the extension; 195 (75%) completed the 24-month extension visit. For on-treatment patients > 95% of the planned daily dose of EC-MPS was administered, and < 13% of patients in both groups had discontinued EC-MPS due to adverse events by 24 months. The overall incidence of adverse events during the extension phase, including infections and hematological abnormalities, was comparable to that seen in the core study, with a similar safety profile in the newly-exposed and long-term EC-MPS groups. There were 3 deaths during the first 24 months of the extension, and 2 graft failures in both the "newly-exposed" and "long-term" EC-MPS groups.

CONCLUSIONS

These data demonstrate that long-term use of EC-MPS is effective and has an acceptable tolerability profile in renal transplant patients, and confirm that conversion of maintenance renal transplant patients from MMF to EC-MPS is a safe therapeutic option.

Profibrotic cytokines and lymphocyte proliferation in stable renal allograft recipients treated with or without cyclosporine A

Profibrotic cytokines such as transforming growth factor-beta 1 (TGF-beta1) and endothelin-1 (ET-1) are involved in the pathogenesis of chronic allograft nephropathy. We assessed the effect of maintenance immunosuppression with or without cyclosporine A on TGF-beta1 and ET-1 expression as well as lymphocyte proliferation in renal allograft recipients. Patients were divided into groups according to their maintenance immunosuppression: A, azathioprine + methylprednisolone; B, cyclosporine A + azathioprine + methylprednisolone. TGF-beta1 and ET-1 plasma concentrations were not different between both groups. TGF-beta1 concentrations in cell culture supernatants and lymphocyte proliferation were higher in group B as compared to group A. No correlation was found between TGF-beta1 plasma concentrations and lymphocyte proliferation. Multiple linear regression analysis revealed that patient characteristics influence TGF-beta1 and ET-1 expression. In conclusion, plasma levels of profibrotic cytokines do not reflect the existing profibrotic potential of immunosuppressive drugs. Demographic factors and the employed co-medication confound the results.

FK506, transforming growth factor-β1 and mesangial matrix synthesis: Parallels and differences compared with cyclosporine A

Cyclosporine A (CsA)-induced glomerulosclerosis is a well-described side effect of CsA treatment. Current evidence indicates that FK506 causes similar morphologic changes. Recently, we demonstrated that CsA up-regulates the expression of transforming growth factor-beta1 (TGF-beta1), its receptors type I (TbetaR-I) and type II (TbetaR-II), as well as related matrix protein synthesis in mesangial cells (MCs). Here, we assessed the effect of FK506 on the expression of TGF-beta1, TbetaR-I, TbetaR-II, fibronectin (FN) and plasminogen activator inhibitor type-1 (PAI-1) in MCs. Resting MCs were incubated with/without FK506. Time- and concentration-dependent expression was measured at the mRNA and protein level. Compared to untreated controls, FK506 stimulated TGF-beta1 mRNA (maximum at 8 h, 100 ng/mL: 2.13+/-0.15-fold, P<0.005) and protein expression (maximum at 96 h, 100 ng/mL: 1.96+/-0.29-fold, P<0.005). In contrast, TbetaR-I and TbetaR-II protein expression remained unchanged. Concerning matrix protein synthesis, FK506 slightly increased FN production (96 h, 100 ng/mL: 1.38+/-0.28-fold, P<0.05), but not PAI-1 production. These results indicate that, comparable to CsA, FK506 induced glomerulosclerosis is also due to a direct effect on mesangial matrix production, which is at least in part mediated via up-regulation of TGF-beta1 expression. The fact that, unlike CsA, FK506 does not increase the expression of TbetaR-I, TbetaR-II, and PAI-1, deserves further investigation.

Effect of pregnancy on long-term kidney function in renal transplant recipients treated with cyclosporine and with azathioprine

In order to investigate the effect of different immunosuppressive regimens and the time interval between transplantation and pregnancy on long-term outcome, we performed a case-control study in pregnant renal allograft recipients. Eighty-one pregnancies of kidney transplanted recipients were identified [cyclosporine (CYA): n = 40; azathioprine (AZA): n = 41]. Controls were matched with respect to important prognostic factors. Posttransplant follow-up was 91.3 +/- 5 months. Graft and patient survival were similar in both groups and there was no apparent effect of immunosuppression. A total of 28 recipients (33%) delivered within 2 years and 6 (8%) subjects within 1 year after transplantation, but these short transplantation-to-pregnancy intervals had no apparent adverse effect on long-term outcome. In contrast to AZA-treated patients, CYA-treated patients experienced an increase in serum creatinine postpartum (1.15 +/- 0.2 mg/dL vs. 1.61 +/- 0.1 mg/dL; p < 0.05). Whole blood CYA levels decreased transiently during pregnancy from 115.9 +/- 8 ng/mL to 80.7 +/- 7 ng/mL leading to a gradual increase in drug dose from 240 +/- 14 mg/day to 324 +/- 21 mg/day (p < 0.05). Following delivery, there was an increase in CYA concentrations to 173 +/- 5.4 ng/mL, requiring rapid dose tapering to baseline of 246 +/- 15 mg/day. Pregnancies in renal recipients do not affect long-term patient and graft survival, independent of the immunosuppression. No detrimental effect of short transplantation-to-pregnancy intervals on long-term graft function was detected.

Cardiovascular risk and renal transplantation: post hoc analyses of the Assessment of Lescol in Renal Transplantation (ALERT) Study

BACKGROUND

Renal transplantation is associated with an increased risk for premature cardiovascular disease. We analyzed the data in the placebo arm of Assessment of Lescol in Renal Transplantation (ALERT) to improve our understanding of the relationship between cardiovascular risk factors and outcomes in this unique population.

METHODS

We performed Cox survival analysis for myocardial infarction, cardiac death, and noncardiac death in 1,052 patients recruited to the placebo arm of ALERT. These subjects were aged 30 to 75 years, had stable graft function at least 6 months after transplantation, had a serum total cholesterol level between 155 and 348 mg/dL (4 and 9 mmol/L), and were receiving cyclosporine-based immunosuppression.

RESULTS

The results confirm previous studies. In multivariate analysis, preexisting coronary heart disease (hazard ratio [HR], 3.69; P < 0.001), total cholesterol level (HR, 1.55 per 50 mg/dL; P = 0.0045), and prior acute rejection (HR, 2.36; P = 0.0023) were independent risk factors. Conversely, independent risk factors for cardiac death were age (HR, 1.58 per decade; P = 0.0033), diabetes (HR, 3.35; P = 0.0002), ST-T changes on the ECG (HR, 3.17; P = 0.0004), and serum creatinine level (HR, 2.65 per milligram per deciliter; P < 0.0001).

CONCLUSION

This analysis confirms that renal transplant recipients share risk factors for myocardial infarction and cardiac death with the general population. However, the pattern of risk factors and their relationship with outcomes is atypical, highlighting the unique nature of cardiovascular risk in transplant recipients.

Lectin-like oxidized low-density lipoprotein (LDL) receptor (LOX-1)-mediated pathway and vascular oxidative injury in older-age rat renal transplants

BACKGROUND

Older-age renal allografts are associated with inferior survival; however, the mechanisms are unclear. Reactive oxygen species participate in aging and in chronic vascular disease. We investigated how mediators of oxidative stress may increase allograft susceptibility to vascular injury.

METHODS

We employed the low-responder allogeneic F344-to-Lew rat renal transplantation model. We used nonimmunosuppressed young (donors and recipients aged 12 weeks), old (donors and recipients aged 52 weeks), and old-to-young animal (donors aged 52 weeks and recipients aged 12 weeks) combinations. Grafts were transplanted after 2 hours cold preservation in University of Wisconsin solution and harvested 1, 2, 7 and 10 days later. Additionally, old animals receiving continuous 1.5 mg/kg cyclosporine (CyA) immunosuppression were included. Renal allograft pathology was scored according to Banff criteria. We studied intragraft vascular adhesion molecule-1 (VCAM-1), lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1), and hypochlorite-modified LDL expression as well as ED-1+ monocytes/macrophages and CD8+ lymphocyte infiltration. Intragraft in situ superoxide anion radical production was determined with dihydroethidium assay on cryosections.

RESULTS

During the first 2 posttransplant days, old transplants demonstrated higher functional impairment and increased oxidative stress, while young transplant had higher ED-1+ monocytes/macrophage infiltration and VCAM-1 expression. The degree of VCAM-1 expression and ED-1+ monocytes/macrophage and CD8+ lymphocyte infiltration correlated at later time points directly with the transplant age. VCAM-1 and LOX-1 staining were localized predominantly on the endothelium of arterial vessels, shifting the distribution to vascular smooth muscle layer strongly dependent on donor age and the grade of vascular injury. LOX-1 staining colocalized with hypochlorite-modified epitopes in the media of injured arteries. We measured increased in situ superoxide anion radical production in corresponding areas. Immunosuppression with CyA had no protective effect on vascular injury and LOX-1 expression.

CONCLUSION

Induction of LOX-1-related oxidation pathways and increased susceptibility to oxidative stress could play an important role in promoting vascular injury in old renal transplants independent of the recipient age.

Differences in reporting of acute rejections between American and European publications of large immunosuppressive trials impair comparability of study results

This study examined the use of different definitions for acute rejection in recent large multicenter trials performed in America and Europe in order to assess whether systematic differences exist between both scientific cultures. We systematically selected recent publications on multicenter randomized controlled trials, investigating immunosuppressive regimens in de novo kidney transplant recipients. Publications included were classified according to the type of acute rejection reported: group 1 reported no or only one type of rejection rate (biopsy-proven or treated); group 2 reported information on both treated and biopsy-proven rates. Other potential factors (journal's impact-factor, study size) were compared within the subgroups. To determine the rates of treated but not biopsy-proven acute rejections, additional analyses were performed within subgroup 2. The reviewed publications were 24/44 (54.5%) European (E) and 20/44 (45.5%) American (A) origin. Eighteen of 44 publications reported no or only one type of rejection rate (group 1); 26 publications reported treated as well as biopsy-proven rates (group 2). Significantly more European publications reported both treated and biopsy-proven rates (E: 18/24 [75.0%] vs A: 8/20 [40.0%]; P = .019). Group 1 American papers were published in higher-ranked journals than European ones. The rate of blindly treated rejections did not differ significantly (A: 6.13% [range 0% to 12.8%] vs E: 8.43% [range 0% to 16.9%]) and the proportion of blindly treated rejections was slightly lower in American studies (A: 18.5% vs E: 26.5%). Our systematic review showed large discrepancies with a trend to report biopsy-proven rejection rates only in recent years.

Two year comparison of sevelamer and calcium carbonate effects on cardiovascular calcification and bone density

BACKGROUND

Calcium-based phosphate binders may induce tissue calcification, and little is known about their effects on bone density. We compared the effects of a calcium with a non-calcium phosphate binder on both arterial calcification and bone density measured by computed tomography.

METHODS

Seventy-two adult haemodialysis patients were randomized to treatment with calcium carbonate (CC) or sevelamer (SEV) for 2 years. Electron beam CT scans were performed at baseline and at 6, 12 and 24 months. Serum phosphorus, calcium, calcium x phosphorus product and intact parathyroid hormone (iPTH) were measured and other routine laboratory tests were also carried out.

RESULTS

The average calcium x phosphorus product was similar in the two treatment groups. However, patients receiving CC had significantly lower average iPTH (P<0.01), were more likely to have hypercalcaemic episodes (P = 0.03) and had significantly greater increases in coronary artery (CC median 484, P<0.0001, SEV median 37, P = 0.3118, between-group P = 0.0178) and aortic (CC median 610, P = 0.0003, SEV median 0, P = 0.5966, between-group P = 0.0039) calcification scores. The CC group also had a significant decrease in trabecular bone density (CC median -6%, P = 0.0049, SEV median +3%, P = 0.0296, between-group P = 0.0025). However, there was no significant difference in cortical bone density between the two groups.

CONCLUSIONS

This 2 year study shows that calcium carbonate use is continuously associated with progressive arterial calcification in haemodialysis patients. In addition, it suggests that it is also associated with decreased trabecular bone density. However, this latter finding requires confirmation by a study specifically devoted to this issue.

Laparoscopic versus Open Donor Nephrectomy in Germany: Impact on Donor Health-Related Quality of Life and Willingness to Donate

INTRODUCTION

Laparoscopic living donor nephrectomy (LDN) offers multiple advantages to the donor. Since 1999 LDN has become the only surgical approach for living kidney donation in our department. To our knowledge a donor health-related quality of life (QoL) has not yet been performed with standardized and validated questionnaires to compare laparoscopic with open nephrectomy. We therefore performed a study with two questionnaires (SF-36/GBB-24) and one set of open questions for all donors in our department.

METHODS

Questionnaires were sent out to all donors between 1983 and 2001 with at least a 1-year follow-up. To exclude a bias a maximum response rate was sought; donors who did not answer were recontacted as well as their recipients or their physicians to motivate them for participation.

RESULTS

The response rate was (89.8%). Except for less limb pain in the laparoscopy group, no difference could be detected for donors QoL with respect to the surgical method. Willingness to donate again was not affected by the surgical method. Nevertheless if asked again today, most donors want laparoscopic kidney retrieval.

CONCLUSIONS

Donors health-related QoL is not affected by the surgical method when queried retrospectively. Nevertheless, most donors today would favor laparoscopy, if they could chose again. How laparoscopy affects a reluctant donor to step forward must be determined in a prospective study.

Cyclosporine C2 levels in de novo renal allograft recipients: a German multicenter prospective observational study

This ongoing multicenter prospective observational study was undertaken in de novo renal allograft recipients managed with cyclosporine (CsA) trough (C0) and 2-hour postdose (C2) level monitoring at defined times so as to assess the risk for an acute rejection episode or allograft dysfunction. The renal transplant recipients (n = 159) were enrolled at 11 German centers. The 6-month posttransplant data from 138 patients were evaluable for this interim analysis. Mean C2 levels (ng/mL), which were measured by liquid chromatography-tandem mass spectrometry at a central laboratory, were: days 3 to 5: 873.1 +/- 391.9; days 7 to 10: 939.1 +/- 422.8; days 14 to 28: 1116.3 +/- 497.6; 3 months: 905.0 +/- 316.8; and after 6 months: 787.0 +/- 276.5. To identify patients at higher risk for acute rejection or allograft dysfunction, we calculated the relative CsA absorption capacity (C2 [ng/mL]/morning dose [mg/kg]; CsA-Abs), yielding mean values on days 3 to 5: 284.4 +/- 115.1; days 7 to 10: 306.7 +/- 134.8; days 14 to 28: 382.5 +/- 164.7; month 3: 501.5 +/- 168.8; month 6: 512.7 +/- 176.5. Three groups were distinguished by CsA-Abs at days 7 to 10: low absorbers (CsA-Abs < 200), normal absorbers (CsA-Abs 200 to 350), and high absorbers (CsA-Abs > 350). A between-group comparison of absorption level at 6 months posttransplant revealed the incidences of biopsy-proven acute rejection and Cockcroft-Gault formula-based mean glomerular filtration rates of 23.8% and 54.7 +/- 19.0 mL/min, 22.6% and 59.5 +/- 20.7 mL/min, and 17.6% and 67.7 +/- 23.5, respectively. In conclusion, mean C2 levels >1000 ng/mL are attained within 2 to 4 weeks, with CsA-Abs increasing continuously over the first 6 posttransplant months. High CsA absorbers show a propensity toward good allograft function and lower acute rejection rates at 6 months after renal transplantation.

Introducing Everolimus (Certican) in Organ Transplantation: An Overview of Preclinical and Early Clinical Developments

Everolimus (Certican) is a novel proliferation signal inhibitor with potent immunosuppressant effects that has been shown to prevent and reverse acute rejection in preclinical models of kidney, heart, and lung transplantation. These effects have been confirmed by clinical studies in which everolimus demonstrated comparable efficacy to azathioprine and mycophenolate mofetil in heart and renal transplantation, respectively, when combined with full-dose cyclosporine (CsA; Neoral). Experimental studies have also shown that everolimus inhibits smooth muscle cell proliferation and prevents neointimal thickening and transplant arteriosclerosis. Importantly, everolimus was shown to significantly reduce both the incidence and severity of cardiac allograft vasculopathy in recipients of heart transplants, which if confirmed in long-term studies, could provide a major advantage in these patients. Use of everolimus was also associated with lower rates of cytomegalovirus infection in both indications. Studies in which everolimus was combined with reduced-exposure CsA have demonstrated significantly improved renal function when compared with full-dose regimens, with no loss of efficacy. The results of preclinical and clinical studies with everolimus thus indicate that this novel proliferation signal inhibitor will be an important addition to the armamentarium by enhancing graft survival and minimizing toxicity.

Beneficial effect of early initiation of lipid-lowering therapy following renal transplantation

BACKGROUND

Renal transplant recipients have a significantly reduced life expectancy, largely due to premature cardiovascular disease. The aim of the current analysis was to investigate the importance of time of initiation of therapy after transplantation, on the benefits of statin therapy.

METHODS

2102 renal transplant recipients with total cholesterol levels of 4.0-9.0 mmol/l were randomly assigned to treatment with fluvastatin (n = 1050) or placebo (n = 1052) and followed for a mean time of 5.1 years. The end-points were major cardiac events. The average median time from transplantation to randomization was 4.5 years (range: 0.5-29 years).

RESULTS

In patients starting treatment with fluvastatin <4.5 years after renal transplantation, the incidence of cardiac events was 4.6% over 5.1 years vs 9.2% in those on placebo (P = 0.007). Fluvastatin significantly reduced the risk of cardiac death and non-fatal myocardial infarction by 56% [risk ratio (RR): 0.44; 95% confidence interval (95% CI): 0.26-0.74; P = 0.002]. In a more detailed analysis patients were grouped into 2-year intervals (since the last transplantation). The frequency of cardiac death and non-fatal myocardial infarction was reduced by 3.2%, 5.1%, 9.6% and 8.2% with fluvastatin treatment as compared to 6%, 10.4%, 13.4% and 9.6% with placebo when treatment was initiated at 0-2, 2-4, 4-6 and >6 years, respectively. The risk reduction for patients initiating therapy with fluvastatin at years 0-2 (compared with >6 years) following transplantation was 59% (RR: 0.41; 95% CI: 0.18-0.92; P = 0.0328). This is also reflected in total time on renal replacement therapy: in patients in the first quartile (<47 months) fluvastatin use was associated with a risk reduction of 64% compared with 19% for patients in the fourth quartile (>120 months) (P = 0.033).

CONCLUSIONS

Our data support an early introduction of fluvastatin therapy in a population of transplant recipients at high risk of premature coronary heart disease.

Functional consequences of a novel uromodulin mutation in a family with familial juvenile hyperuricaemic nephropathy

BACKGROUND

Familial juvenile hyperuricaemic nephropathy (FJHN) is an autosomal-dominant disorder featuring hyperuricaemia, low fractional urate excretion, interstitial nephritis and chronic renal failure. The responsible gene UMOD was recently identified. UMOD encodes for uromodulin or Tamm-Horsfall glycoprotein, the most abundant protein in normal urine. We encountered a family with FJHN and identified a novel UMOD mutation in exon 6.

METHODS

We sequenced the gene in all family members, identified the mutation, and verified its presence in the affected members. We next performed functional studies of the mutant protein by immunofluorescence and FACS analysis on transfected cells.

RESULTS

The mutation p.C347G (c.1039T > G) results in a conserved cysteine to glycine amino acid substitution in the uromodulin zona pellucida (ZP) domain. The cell studies showed that the novel uromodulin mutation causes a delay in protein export to the plasma membrane due to its retention in the endoplasmic reticulum.

CONCLUSIONS

We describe the first reported mutation mapping in the ZP uromodulin domain. Our data provide further evidence showing why the excretion of uromodulin is reduced in this syndrome.

Safety and Efficacy After Conversion From Mycophenolate Mofetil to Enteric-Coated Mycophenolate Sodium: Results of a 1-Year Extension Study

Enteric-coated mycophenolate sodium (EC-MPS) is an enteric-coated formulation of mycophenolic acid. A 12-month, multicenter, double-blind, randomized clinical study demonstrated that converting maintenance renal transplant patients from mycophenolate mofetil (MMF) to EC-MPS is safe and does not affect efficacy. In an open-label study extension, 130 patients initially randomized to MMF were converted to EC-MPS (newly exposed); 130 initially randomized to EC-MPS continued on EC-MPS (EC-MPS long-term). A composite endpoint of biopsy-proven acute rejection (BPAR), graft loss, or death occurred in 3 (2.3%) newly exposed and 2 (1.5%) EC-MPS long-term patients during the extension phase. One patient died and one lost his graft. BPAR occurred in 3 (2.3%) newly exposed patients and 1 (0.8%) EC-MPS long-term patient. During the first 12 months of the extension phase, incidence and type of adverse events was similar in both groups and comparable to that seen in the core study. Nine cases of malignancy were reported, mainly nonmelanoma skin cancers. EC-MPS dose adjustments for adverse events were required in <12% of patients. At the end of the 12-month extension, 58 (44.6%) and 64 (49.2%) newly exposed and EC-MPS long-term patients, respectively, had reported at least one gastrointestinal adverse event. Mean serum creatinine remained stable at the 12-month visit of the extension study (137 micromol/L in the newly exposed and 142 micromol/L in the EC-MPS long-term groups). The results of this study demonstrate the long-term safety of EC-MPS and reconfirm the safety of converting MMF maintenance renal transplant patients to EC-MPS.

Angiotensin II type 1-receptor activating antibodies in renal-allograft rejection

BACKGROUND

Antibodies against HLA antigens cause refractory allograft rejection with vasculopathy in some, but not all, patients.

METHODS

We studied 33 kidney-transplant recipients who had refractory vascular rejection. Thirteen had donor-specific anti-HLA antibodies, whereas 20 did not. Malignant hypertension was present in 16 of the patients without anti-HLA antibodies, 4 of whom had seizures. The remaining 17 patients had no malignant hypertension. We hypothesized that activating antibodies targeting the angiotensin II type 1 (AT1) receptor might be involved.

RESULTS

Activating IgG antibodies targeting the AT1 receptor were detected in serum from all 16 patients with malignant hypertension and without anti-HLA antibodies, but in no other patients. These receptor-activating antibodies are subclass IgG1 and IgG3 antibodies that bind to two different epitopes on the second extracellular loop of the AT1 receptor. Tissue factor expression was increased in renal-biopsy specimens from patients with these antibodies. In vitro stimulation of vascular cells with an AT1-receptor-activating antibody induced phosphorylation of ERK 1/2 kinase and increased the DNA binding activity of the transcription factors activator protein 1 (AP-1) and nuclear factor-kappaB. The AT1 antagonist losartan blocked agonistic AT1-receptor antibody-mediated effects, and passive antibody transfer induced vasculopathy and hypertension in a rat kidney-transplantation model.

CONCLUSIONS

A non-HLA, AT1-receptor-mediated pathway may contribute to refractory vascular rejection, and affected patients might benefit from removal of AT1-receptor antibodies or from pharmacologic blockade of AT1 receptors.

Risk Factors for Reaching Renal Endpoints in the Assessment of Lescol in Renal Transplantation (ALERT) Trial

BACKGROUND

The aim of the study was to identity risk factors for long-term renal transplant function and development of chronic allograft nephropathy (CAN) in renal transplant recipients included in the Assessment of Lescol in Renal Transplantation (ALERT) trial.

METHODS

The ALERT trial was a randomized, double-blind, placebo-controlled study of the effect of fluvastatin, 40 and 80 mg/day, in renal transplant recipients who were randomized to receive fluvastatin (Lescol) (n = 1,050) or placebo (n = 1,052) over 5 to 6 years of follow-up. Renal endpoints including graft loss or doubling of serum creatinine or death were analyzed by univariate and multivariate regression analysis in the placebo group.

RESULTS

There were 137 graft losses (13.5%) in the placebo group, mainly caused by CAN (82%). Univariate risk factors for graft loss or doubling of serum creatinine were as follows: serum creatinine, proteinuria, hypertension, pulse pressure, time since transplantation, donor age, human leukocyte antigen-DR mismatches, treatment for rejection, low high-density lipoprotein cholesterol, and smoking. Multivariate analysis revealed independent risk factors for graft loss as follows: serum creatinine (relative risk [RR], 3.12 per 100-microM increase), proteinuria (RR, 1.64 per 1-g/24 hr increase), and pulse pressure (RR, 1.12 per 10 mm Hg), whereas age was a protective factor. With patient death in the composite endpoint, diabetes mellitus, smoking, age, and number of transplantations were also risk factors.

CONCLUSIONS

Independent risk factors for graft loss or doubling of serum creatinine or patient death are mainly related to renal transplant function, proteinuria, and blood pressure, which emphasizes the importance of renoprotective treatment regimens in this population.

FTY720: early clinical experience

FTY720 is the first in a new class of immunomodulators--sphingosine 1-phosphate receptor (S1P-R) agonists. It is highly effective in prolonging allograft survival in preclinical models of transplantation. Furthermore, FTY720 acts synergistically with calcineurin inhibitors and proliferation inhibitors in these models, suggesting that use of FTY720 in combination with classical immunosuppressants may be a promising new option for transplant patients. Phase I studies conducted in stable renal transplant patients maintained on a cyclosporine (CsA)-based regimen have revealed a tolerable profile of FTY720 for transplant pharmacotherapy. The pharmacokinetics of FTY720 is characterized by linear dose-proportional exposure over a wide range of doses, only moderate interpatient variability, and a prolonged elimination half-life (t(1/2) 89 to 157 hours). These factors suggest that FTY720 can be administered according to a simple once-daily schedule, without the need for blood-level monitoring or dose titration. The pharmacodynamics of FTY720 in humans are characterized by a significant reduction in peripheral blood count by up to 85%. In contrast to the nonspecific myelosuppressive effects of other immunosuppressants, this effect of FTY720 is specific for lymphocytes, with no effect observed on monocytes or granulocytes. In combination with CsA, FTY720 was well tolerated following single or multiple dosing, without any evidence of additional toxicities, indicating that FTY720 may be useful in the future design of more effective and less toxic regimens for prevention of graft rejection.

Impact of cyclosporine on the development of immunosuppressive therapy

With the advent of cyclosporine (CsA) 20 years ago, graft survival increased considerably to more than 80% at 2 years posttransplant. The early formulation of CsA, Sandimmun, is effective in preventing organ rejection, although its absorption profile means it is subject to a high degree of variability. The development of a microemulsion formulation, Neoral, provided a therapy with superior efficacy in kidney, liver, and heart transplantation with an improved pharmacokinetic profile. Calcineurin inhibitors (CNIs), including CsA, have a narrow therapeutic range, so frequent blood measurements to control drug levels are required. Recent research has demonstrated that the measurement of blood CsA concentration at 2 hours postdosing--C2 monitoring--has the potential to optimize efficacy and reduce the side effects associated with CNI use. In heart and de novo kidney transplantation, C2 monitoring may help to further reduce the incidence of acute rejection, while in maintenance renal transplant recipients, C2 monitoring can help to detect overexposure and thus allows safe dose reduction, which may improve blood pressure and renal function. C2 monitoring thus facilitates a better balance between effective Neoral immunosuppression and unwanted side effects. Today, CsA remains the cornerstone of immunosuppression, and ongoing studies aim to further optimize patient management strategies with Neoral. With other trials evaluating the impact of Neoral in combination with newer therapies such as Certican, myfortic, and FTY720, the use of CsA in transplant recipients looks set to continue.

Quality of life of living kidney donors in Germany: a survey with the Validated Short Form-36 and Giessen Subjective Complaints List-24 questionnaires

BACKGROUND

Most studies evaluating the impact of kidney donation on donors' quality of life (QOL) have limitations such as small cohort size, unmatched references, use of nonstandardized and nonvalidated questionnaires, or low response rates.

METHODS

We performed a study on donors' QOL that was designed to avoid these limitations. All available living renal donors in our department in the last 18 years were included in the study. QOL was assessed with two validated, standardized questionnaires (Short Form-36, Giessen Subjective Complaints List [Giessener Beschwerdebogen]-24) and compared with gender- and age-matched references. In addition, specific questions relating to kidney donation were asked.

RESULTS

The response rate (89.8%) is one of the highest reported for studies on QOL of living kidney donors. Most donors had an equal or better QOL than the healthy population. Donors' willingness to donate again (93.4%) or recommend living-donor kidney transplantation (92.4%) was high, irrespective of complications. A small number of donors experienced financial drawbacks or occupational disadvantages. Donors aged 31 to 40 years were found to be at risk of QOL deterioration after organ donation. Donor and recipient complications had a significant impact on donors' QOL. One third of the donors found that the psychologic care preceding and after kidney donation was insufficient.

CONCLUSIONS

Our findings support the practice of living-donor kidney transplantation as a good means to meet the persisting organ shortage. Further effort must be put into minimizing donor and recipient complications. The specific demands of younger donors should be further elucidated. In addition to medical follow-up, living kidney donors should also be offered lifelong psychologic counseling.

Pre-transplant inosine monophosphate dehydrogenase activity is associated with clinical outcome after renal transplantation

Mycophenolate mofetil (MMF), an inhibitor of inosine monophosphate dehydrogenase (IMPDH) activity, is usually administered as a standard dose of 1 g b.i.d. after renal transplantation. Because MMF dose reductions are associated with inferior outcome, we investigated pre-transplant IMPDH activity, MMF dose reductions and outcome. IMPDH activity was determined in isolated peripheral mononuclear cells immediately prior to renal transplantation. We observed considerable inter-individual variability in pre-transplant IMPDH activity (9.35 +/- 4.22 nmol/mg/h). Thirty of 48 patients (62.5%) with standard MMF dose (1 g b.i.d.) had dose reductions within 3 years post-transplant; these patients also had significantly lower IMPDH activity. The area under the receiver-operating characteristics curve (AUC-ROC) for prediction of dose reduction within 6 months post-transplant was 0.75 (95% CI, 0.61-0.89; p < 0.004). IMPDH activity above the cut-off value, MMF dose reduction and age of recipient were significant contributors for the occurrence of acute rejection in the multivariate logistic regression. Patients with high IMPDH activity and MMF dose reduction had the highest rejection rate (81.8% vs. 36.4%; p < 0.01).

CONCLUSION

Patients with low IMPDH activity experienced more complications of MMF therapy. High pre-transplant IMPDH activity and MMF dose reductions were associated with rejection. Determination of IMPDH activity prior to transplantation may help to improve MMF therapy after renal transplantation.