Low-dose cyclosporine and mycophenolate mofetil in renal allograft recipients with suboptimal renal function

Reducing Adverse Effects of Immunosuppressive Agents in Kidney Transplant Recipients

Success in solid organ transplantation with minimal complications can now be achieved for most patients, and a remarkable rate of graft and patient survival can also be expected. However, the potential for adverse events and comorbid conditions increases with longer graft survival. Although the immunosuppressive regimen is central to the outcome of the transplant recipient and directly impacts the survival of the graft, chronic use of immunosuppressive agents is associated with metabolic disturbances such as hypertension, hyperlipidemia, loss of bone density, nephrotoxicity, and diabetes, which may contribute to other comorbid conditions. In addition, changes in appearance, gingival hyperplasia, hirsutism, alopecia, and weight gain disrupt quality of life and may lead to noncompliance with the immunosuppressive regimen. New immunosuppressive medications, including mycophenolate mofetil, sirolimus, basiliximab, and daclizumab, have allowed for experimentation with new regimens designed to reduce or allow discontinuation of corticosteroids and calcineurin inhibitors. This review highlights the impact and cost of immunosuppressive side effects and the potential for new immunosuppressive regimens to reduce this substantial clinical burden in transplantation.

Late Conversion of Kidney Transplant Recipients from Ciclosporin to Tacrolimus Improves Graft Function: Results from a Randomized Controlled Trial

Background

Tacrolimus (TAC) to ciclosporin A (CSA) conversion studies in stable kidney transplant recipients have reported varying effects on graft function. Here we study graft function (eGFR) trajectories using linear mixed models, which provide effect estimates on both slope and baseline level of GFR and offer increased statistical power.

Methods

Secondary analysis of a randomized controlled trial of CSA treated kidney transplant recipients with stable graft function assigned to receive 0.1 mg/kg/day TAC (target 5–8 ng/ml) or to continue CSA based immunosuppression (target 70–150 ng/ml) at a 2:1 ratio. Renal graft function was estimated via the MDRD (eGFR_MDRD) and CKD-EPI (eGFR_CKD-EPI) formulas.

Results

Forty-five patients continued CSA and 96 patients were converted to TAC with a median follow up of 24 months. Baseline demographics (except for recipient age) including native kidney disease, transplant characteristics, kidney graft function, medication use and comorbid conditions did not differ between groups. In respect to long-term renal graft function, linear mixed models showed significantly improved eGFR trajectories (eGFR_MDRD: p<0.001, eGFR_CKD-EPI: p<0.001) in the TAC versus CSA group over 24 months of follow up. Estimated eGFR_CKD-EPI group differences between TAC and CSA were −3.49 (p = 0.019) at 3 months, −5.50 (p<0.001) at 12 months, and −4.48 ml/min/1.73m² (p = 0.003) at 24 months of follow up. Baseline eGFR was a significant predictor of eGFR trajectories (eGFR_MDRD: p<0.001, eGFR_CKD-EPI: p<0.001). Significant effects for randomization group were evident despite short-term trough levels in the supratherapeutic range (27% (n = 26) of TAC patients at week one). Median TAC trough levels were within target range at week 4 after conversion.

Conclusion

Conversion of CSA treated kidney transplant recipients with stable graft function to TAC (target 5–8 ng/ml) showed significantly improved long-term eGFR trajectories when compared to CSA maintenance (target 70–150 ng/ml).

Trial Registration

ClinicalTrials.gov NCT00182559 EudraCT identifier: 2004-004209-98

Safety and effectiveness of mycophenolate in systemic sclerosis. A systematic review

Background

Mycophenolate is increasingly being used in the rheumatic diseases. Its main adverse effects are gastrointestinal, myelosuppression, and infection. These may limit use in systemic sclerosis (SSc) since gastrointestinal involvement is common. The objective of this study is to evaluate gastrointestinal adverse events of mycophenolate in SSc. Secondarily we evaluated other adverse events, and the effectiveness of mycophenolate in skin and lung disease.

Methods

A literature search of Medline, Embase, Cochrane Central Register of Controlled Trials, and CINAHL (inception-2013) was performed. Studies reporting use of mycophenolate in SSc patients, adverse events, modified Rodnan skin score (MRSS), forced vital capacity (FVC), or diffusing capacity of carbon monoxide (DLCO) were included. The primary outcome was gastrointestinal events occurring after the initiation of mycophenolate. Secondary safety outcomes included myelosuppression, infection, malignancy, and death after the initiation of mycophenolate.

Results

617 citations were identified and 21 studies were included. 487 patients were exposed to mycophenolate. The mean disease duration ranged between 0.8-14.1 years. There were 18 deaths and 90 non-lethal adverse events. The non-lethal adverse events included 43 (47.7%) gastrointestinal events, 34 (26%) infections, 6 (5%) cytopenias and 2 (2%) malignancies. The most common gastrointestinal events included diarrhea (n=18 (14%)), nausea (n=12 (9%)), and abdominal pain (n=3 (2%)). The rate of discontinuation ranged between 8%-40%. Seven observational studies reported improvement or stabilization in FVC, and 5 studies report stabilization or improvement in MRSS.

Conclusion

Mycophenolate-associated gastrointestinal adverse events are common in SSc, but not severe enough to preclude its use. Observational data suggests mycophenolate may be effective in improving or stabilizing interstitial lung disease, and skin involvement.

The anti-fibrotic effect of mycophenolic acid-induced neutral endopeptidase

Mycophenolic acid (MPA) appears to have anti-fibrotic effects, but the molecular mechanisms underlying this are unknown. We prospectively studied 35 stable kidney transplant recipients maintained on cyclosporine and azathioprine. We converted 20 patients from azathioprine to enteric-coated mycophenolate sodium (EC-MPS) and continued the remaining 15 patients on azathioprine. Exploratory mRNA expression profiling, performed on five randomly selected EC-MPS patients, revealed significant upregulation of neutral endopeptidase (NEP), which is an enzyme that degrades angiotensin II. We confirmed these microarray data by measuring levels of NEP expression in all subjects; in addition, we found that NEP gene expression correlated inversely with proteinuria. In an additional 33 patients, glomerular and tubular NEP protein levels from renal graft biopsies were significantly higher among the 13 patients receiving cyclosporine + EC-MPS than among the 12 patients receiving cyclosporine + azathioprine or 8 patients receiving cyclosporine alone. Glomerular NEP expression inversely correlated with glomerulosclerosis and proteinuria, and tubular NEP expression inversely correlated with interstitial fibrosis. Incubation of human proximal tubular cells with MPA increased NEP gene expression in a dose- and time-dependent manner. Moreover, MPA reduced angiotensin II-induced expression of the profibrotic factor plasminogen activator inhibitor-1, and a specific NEP inhibitor completely reversed this effect. Taken together, our data suggest that MPA directly induces expression of neutral endopeptidase, which may reduce proteinuria and slow the progression of renal damage in kidney transplant recipients.

Long-Term Impact of Cyclosporin Reduction with MMF Treatment in Chronic Allograft Dysfunction: REFERENECE Study 3-Year Follow Up

Calcineurin inhibitor (CNI) toxicity contributes to chronic allograft nephropathy (CAN). In the 2-year, randomized, study, we showed that 50% cyclosporin (CsA) reduction in combination with mycophenolate mofetil (MMF) treatment improves kidney function without increasing the risk for graft rejection/loss. To investigate the long-term effect of this regimen, we conducted a follow up study in 70 kidney transplant patients until 5 years after REFERENCE initiation. The improvement of kidney function was confirmed in the MMF group but not in the control group (CsA group). Four graft losses occurred, 2 in each group (graft survival in the MMF group 95.8% and 90.9% in control group). One death occurred in the control group. There was no statistically significant difference in the occurrence of serious adverse events or acute graft rejections. A limitation is the weak proportion of patient still remaining within the control group. On the other hand, REFERENCE focuses on the CsA regimen while opinions about the tacrolimus ones are still debated. In conclusion, CsA reduction in the presence of MMF treatment seems to maintain kidney function and is well tolerated in the long term.

Mycophenolate mofetil and calcineurin-inhibitor reduction: recent progress

Mycophenolate mofetil (MMF) in combination with calcineurin inhibitors (CNIs) has greatly contributed to acute rejection rate reduction. Because of its immunosuppressive potency it was initially thought that MMF would help in reducing/avoiding CNI-related nephrotoxicity. Elective avoidance of CNI in induction and maintenance MMF-based immunosuppression has resulted in an increased risk for acute and chronic rejection. A recent meta-analysis suggests that CNI elimination in patients on MMF with progressive renal dysfunction is associated with a better outcome, although more data are needed to support any recommendation. So far, the more conservative approach involving CNI minimization with MMF has been associated with amelioration of renal function and low risk for rejection, providing an adequate risk/benefit balance. However, MMF with belatacept might pave the way for CNI-free induction and maintenance immunosuppression. Meanwhile, the assessment of immunological risk by new monitoring tools could be a prerequisite to further implement such CNI sparing strategies.

Mycophenolic acid formulations in adult renal transplantation - update on efficacy and tolerability

The description more than 30 years ago of the role of de novo purine synthesis in T and B lymphocytes clonal proliferation opened the possibility for selective immunosuppression by targeting specific enzymatic pathways. Mycophenolic acid (MPA) blocks the key enzyme inosine monophosphate dehydrogenase and the production of guanosine nucleotides required for DNA synthesis. Two MPA formulations are currently used in clinical transplantation as part of the maintenance immunosuppressive regimen. Mycophenolate mofetil (MMF) was the first MPA agent to be approved for the prevention of acute rejection following renal transplantation, in combination with cyclosporine and steroids. Enteric-coated mycophenolate sodium (EC-MPS) is an alternative MPA formulation available in clinical transplantation. In this review, we will discuss the clinical trials that have evaluated the efficacy and safety of MPA in adult kidney transplantation for the prevention of acute rejection and their use in new combination regimens aiming at minimizing calcineurin inhibitor toxicity and chronic allograft nephropathy. We will also discuss MPA pharmacokinetics and the rationale for therapeutic drug monitoring in optimizing the balance between efficacy and safety in individual patients.

Improved long-term graft function in pediatric transplant renal recipients with chronic allograft nephropathy

CAN is the leading cause of graft loss in pediatric renal transplant recipients. A retrospective single centre analysis of pediatric transplant patients with CAN treated with MMF in conjunction with CNI minimisation/withdrawal is reported. 35 children were successfully started on MMF. The mean age at transplant was 7.9 +/- 0.1 years. MMF was introduced 3.5 +/- 0.1 years after transplantation and patients were followed up for a mean of 32.2 +/- 0.5 months. CAN was confirmed on biopsy in 31 patients. CNI was stopped in 23 patients at a mean time of 16.5 +/- 0.6 months after MMF introduction and minimised in the remaining patients. Prior to MMF introduction, GFR was deteriorating by 21.6 +/- 0.07 ml/min/1.73 m(2)/yr. After MMF, there was an overall improvement in GFR of 4.0 +/- 0.03 ml/min/1.73 m(2)/yr. This was most marked in the first six months when the GFR improved by 20.8 +/- 0.06 ml/min/1.73 m(2)/day. Mean acute rejection episode rate prior to MMF was significantly reduced after MMF introduction. MMF was discontinued in a total of 4 patients due to adverse effects. CNI minimisation/withdrawal with MMF introduction is safe and leads to significant initial improvement with subsequent stabilisation of GFR and improved long term graft survival in pediatric renal transplant recipients with CAN.

Minimization of calcineurin inhibitors to improve long-term outcomes in kidney transplantation

Long-term outcomes after kidney transplantation remain suboptimal, despite the great achievements observed in recent years with the use of modern immunosuppressive drugs. Currently, the calcineurin inhibitors (CNI) cyclosporine and tacrolimus remain the cornerstones of immunosuppressive regimens in many centers worldwide, regardless of their well described side-effects, including nephrotoxicity. In this article, we review recent CNI-minimization strategies in kidney transplantation, while emphasizing on the importance of long-term follow-up and patient monitoring. Finally, accumulating data indicate that low-dose CNI-based regimens would provide an interesting balance between efficacy and toxicity.

Long-term efficacy and safety of a calcineurin inhibitor-free regimen in live-donor renal transplant recipients

Calcineurin inhibitor (CNI) nephrotoxicity is a major concern after renal transplantation. To investigate the safety and efficacy of a CNI-free immunosuppressive regimen, 132 live-donor renal transplant recipients were included in a prospective, randomized controlled trial. All patients received induction therapy with basiliximab and steroids. The patients were randomized to a maintenance immunosuppression regimen that included steroids, sirolimus, and either low-dose tacrolimus or mycophenolate mofetil (MMF). Over a mean follow-up period of approximately 5 yr, patient and graft survival did not significantly differ between the two maintenance regimens. Patient survival was 93.8% and 98.5% in the tacrolimus/sirolimus and MMF/sirolimus groups, respectively, and graft survival was 83% and 88%, respectively. However, the MMF/sirolimus group had significantly better renal function, calculated by Cockcroft-Gault, from the second year post-transplant until the last follow-up. In addition, this group was less likely to require a change in their primary immunosuppression regimen than the tacrolimus/sirolimus group (20.8% versus 53.8%, P = 0.001). The safety profile was similar between groups. In summary, after long-term follow-up, a CNI-free maintenance regimen consisting of sirolimus, MMF, and steroids was both safe and efficacious among low to moderate immunologic risk renal transplant recipients.

Calcineurin inhibitor-sparing regimens in solid organ transplantation: focus on improving renal function and nephrotoxicity

BACKGROUND

The calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, have had a revolutionary effect on the overall success of renal transplantation through reduction in early immunologic injury and acute rejection rates. However, the CNIs have a significant adverse impact on renal function and cardiovascular disease, and extended long-term graft survival has not been achieved. The recognition of these effects sparked interest in CNI-sparing strategies. Strategies to limit CNI exposure include CNI minimization, avoidance, and withdrawal. We sought to review the impact of CNI-sparing strategies in kidney, liver, and heart transplantation.

MATERIALS AND METHODS

A PubMed search 1966 to August 2006 was conducted to identify relevant research articles, and the references of these articles as well as the authors' personal files were reviewed.

RESULTS

Calcineurin inhibitor minimization using mycophenolate mofetil or sirolimus may be associated with a modest increase in creatinine clearance (CrCl) and a decrease in serum creatinine (SCr) in the short term. Despite improvement in CrCl or SCr, CNI nephrotoxicity and chronic allograft nephrotoxicity are progressive over time when CNI exposure is maintained. In kidney transplantation, the tubulo-interstitial and glomerular damage are irreversible. Mycophenolate mofetil may improve renal outcomes during CNI minimization more than sirolimus, and antibody induction may be effective to limit CNI exposure, but longer-term follow-up data are required. Use of sirolimus with mycophenolate mofetil or azathioprine to avoid CNI exposure de novo has improved glomerular filtration rate for at least two yr in most studies in kidney transplantation; however, experience is limited in liver and heart transplantation, and reports of delayed graft function and wound healing with sirolimus may have dampened enthusiasm for de novo use. Late CNI withdrawal has achieved variable results, possibly because withdrawal was attempted after the kidney damage was too extensive. Early CNI withdrawal, prior to significant graft damage, has generally improved CrCl and markers of fibrosis and decreased chronic allograft lesions, a finding also observed with sirolimus in most CNI avoidance studies. Successful withdrawal appears to be more effective than CNI minimization.

CONCLUSIONS

Calcineurin inhibitors are associated with significant nephrotoxicity and chronic kidney damage. Minimization is associated with a modest increase in renal function, but persistent damage is observed on biopsies as long as the CNIs are continued. Avoidance is hampered by lack of experience and possible sirolimus-induced side effects. CNI withdrawal may be the best option by delivering CNIs during the early period of immunologic graft injury and then converting them to less nephrotoxic agents before significant renal damage occurs.

Calcineurin Inhibitor Reduction Based on Maintenance Immunosuppression With Mycophenolate Mofetil in Renal Transplant Patients: POP Study

Since calcineurin inhibitors (CNI) have been introduced, they have become the cornerstone of immunosuppression for renal transplant patients, but their cardiovascular and neurological toxicities, and primarily their renal toxicity, have brought about an increased effort to find combinations of immunosuppressants that are either CNI-free or that use minimum doses of these drugs. The weight of immunosuppression therefore lies with drugs that have a better toxicity profile. The POP observational transverse study including 213 renal transplant patients was designed to study CNI minimization strategies. The mean time of transplant evolution to the time of reduction was 9.9 +/- 11.8 months. The acute rejection rate to the start of reduction was 9.4%. Almost all the patients were undergoing treatment with CNI + mycophenolate mofetil (MMF) + steroids in the immediate posttransplantation period. When reduction was chosen, all patients were undergoing treatment with MMF (mean dose at the start of reduction = 1490.7 +/- 478.0 mg/d). Among the cohort, 66.7% of patients were being treated with tacrolimus (mean C0 levels 13.3 +/- 6.6 ng/mL) and 33.3% with cyclosporine (mean C0 levels 192.2 +/- 94.0 ng/mL; mean C2 levels 1097.5 +/- 457.6). The main reasons for withdrawal were nephrotoxicity (55.9% of the cases), as well as prevention of adverse effects (21.6%). The mean target CNI dose reduction was 41.4% +/- 21.45% in the tacrolimus group and 28.6 +/- 10.0% in the cyclosporine group. In conclusion, CNI toxicity, primarily renal toxicity, makes reduction of these drugs based on the use of full MMF doses an alternative to manage renal transplant patients.

Antifibrotic actions of mycophenolic acid

Mycophenolic acid (MPA) is a highly selective, non-competitive and reversible inhibitor of the inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme in the de novo biosynthesis of guanosine nucleotides. Mycophenolate mofetil (MMF, the ester prodrug of MPA) strongly inhibits both T- and B-lymphocyte proliferation and has now been widely used in the prevention of acute and chronic allograft rejection. Recent evidence, however, suggests that MMF is also capable of inhibiting the proliferation of non-immune cells. In various cell lines, e.g. smooth muscle cells, renal tubular cells, mesangial cells, and fibroblasts, MPA reduced or even abrogated proliferation in response to proliferative stimuli. In animal studies, MMF ameliorated renal lesions in immune-mediated disease, e.g. in the Anti-Thy 1.1 model and experimental lupus nephritis, but was also effective in non-immune-mediated renal damage, e.g. in the rat remnant kidney model or in a model of chronic cyclosporine nephrotoxicity in the rat. In humans, MMF reduced proteinuria in steroid-resistant nephrotic syndrome and had beneficial effects in the prevention and treatment of chronic allograft nephropathy and calcineurin inhibitor toxicity through the reduction of immune- and non-immune-mediated renal damage. MMF is well tolerated and has proven to be a relatively safe drug. Taken together, there is a growing body of evidence pointing to therapeutic applications of MMF other than immunosuppression, in particular the prevention of fibrosis.

Cyclosporine sparing with mycophenolate mofetil, daclizumab and corticosteroids in renal allograft recipients: the CAESAR Study

Although the calcineurin inhibitors (CNI) cyclosporine (CsA) and tacrolimus are highly effective immunosuppressants, they are associated with serious side effects. There is great interest in immunosuppressive regimens that permit reduction or elimination of CNIs, while maintaining adequate immunosuppression and acceptable acute rejection rates. Patients (n = 536) receiving their first renal allograft were randomized to one of three immunosuppressant regimens: daclizumab, mycophenolate mofetil (MMF), corticosteroids (CS) and low-dose CsA (target trough levels of 50-100 ng/mL), weaned from month 4 and withdrawn by month 6; daclizumab, MMF, CS and low-dose CsA; or MMF, CS and standard-dose CsA. Mean GFR 12 months after transplantation (primary end point) was not statistically different in the CsA withdrawal and low-dose CsA groups (both 50.9 mL/min/1.73 m(2)) vs. the standard-dose CsA group (48.6 mL/min/1.73 m(2)). At 12 months, the incidence of biopsy-proven acute rejection was significantly higher in the CsA withdrawal group (38%) vs. the low- or standard-dose CsA groups (25.4% and 27.5%, respectively; p < 0.05). In summary, a regimen of continuous low-dose CsA with MMF, CS and daclizumab induction is a clinically safe and effective immunosuppressive regimen in renal transplant recipients.

Mycophenolate mofetil is associated with altered expression of chronic renal transplant histology

Mycophenolate mofetil (MMF) reduces acute rejection in controlled trials of kidney transplantation and is associated with better registry graft survival. Recent experimental studies have demonstrated additional antifibrotic properties of MMF, however, human histological data are lacking. We evaluated sequential prospective protocol kidney biopsies from two historical cohorts treated with cyclosporine (CSA)-based triple therapy including prednisolone and either MMF (n = 25) or azathioprine (AZA, n = 25). Biopsies (n = 360) were taken from euglycemic kidney-pancreas transplant recipients. Histology was independently assessed by the Banff schema and electron microscopic morphometry. MMF reduced acute rejection and OKT3 use (p < 0.05) compared with AZA. MMF therapy was associated with limited chronic interstitial fibrosis, striped fibrosis and periglomerular fibrosis (p < 0.05-0.001), mesangial matrix accumulation (p < 0.01), chronic glomerulopathy scores (p < 0.05) and glomerulosclerosis (p < 0.05). MMF was associated with delayed expression of CSA nephrotoxicity, reduced arteriolar hyalinosis, striped fibrosis and tubular microcalcification (p < 0.05-0.001). The beneficial effects of MMF remained in recipients without acute rejection. Retrospective analysis shows that MMF therapy was associated with substantially reduced fibrosis in the glomerular, microvascular and interstitial compartments, and a delayed expression of CSA nephrotoxicity. These outcomes may be due to a limitation of immune-mediated injury and suggest a direct effect of reduced fibrogenesis.

Impact of cyclosporine reduction with MMF: a randomized trial in chronic allograft dysfunction. The 'reference' study

Long-term use of calcineurine inhibitors (CNIs) may contribute to the development of chronic allograft dysfunction (CAD). We investigate the impact of the introduction of MMF combined with cyclosporine (CsA) 50% dose reduction. An open, randomized, controlled, multicenter, prospective study was conducted in 103 patients, receiving a CsA-based therapy with a serum creatinine between 1.7-3.4 mg/dL, more than 1 year after transplantation. They were randomized to receive MMF with half dose of CsA (MMF group) or to continue their maintenance CsA dose (control group). A total of 96 weeks after randomization, the evolution of renal function assessed by regression line analysis of 1/SeCr improved in the MMF group (positive slope) vs. the control group (negative slope), 4.2 x 10(-4) vs. -3.0 x 10(-4), respectively (p < 0.001). Concurrently, the absolute renal function improved significantly in the MMF group. No episode of biopsy-proven acute rejection occurred. One patient in each group lost his graft because of biopsy-proven chronic allograft nephropathy. There was a significant decrease of triglycerides level in the MMF group. Anemia and diarrhea were statistically more frequent in the MMF group. In CAD, the reduction of CsA in the presence of MMF results in significant improvement in renal function during a 2-year follow-up.

Maintenance immunosuppression regimens: conversion, minimization, withdrawal, and avoidance

A wide choice of drug combinations is available to clinicians for immunosuppression regimens for their kidney transplant patients. Although many protocols have minimized early graft loss, the optimal long-term regimen is unknown. Recent studies clearly showed that cardiovascular death is now the leading cause of graft loss. Strategies must be developed that address this risk while keeping immunologic events low. Transplant physicians have focused on exploring regimens that minimize or avoid the use of corticosteroids. Studies also have started to explore protocols that minimize calcineurin inhibitor therapy.

Calcineurin Inhibitor Avoidance with Daclizumab, Mycophenolate Mofetil, and Prednisolone in DR-Matched de Novo Kidney Transplant Recipients

BACKGROUND

Calcineurin inhibitor (CNI)-free regimens posttransplantation have been claimed to conserve graft function in addition to reduce the risk factors for cardiovascular and malignant disease in renal transplant recipients.

METHODS

The primary aim of this prospective, open-label, randomized, parallel-group, single-center study was to compare the effect of complete CNI-avoidance posttransplant (daclizumab + mycophenolate mofetil + prednisolone: Dac-group, n=27) with the standard CNI-based immunosuppressive protocol at our transplant unit (cyclosporine A + mycophenolate mofetil + prednisolone: CsA-group, n=27) on renal function (glomerular filtration rate [GFR] determined as plasma clearance of 51Cr-EDTA) in a selected low immunogenic risk population (DR-matched, PRA-negative de novo cadaveric transplant recipients).

RESULTS

There were no significant difference in GFR at week 10 (P=0.61), but GFR was significantly (P=0.029) lower in the Dac-group (52+/-20 ml/min) at month 12 than in the CsA-group (69+/-29 ml/min). One-year patient and graft survival did not differ between the two groups. Overall acute rejection rate was 70.4% (19/27) in the Dac-group and 29.6% (8/27) in the CsA-group (P=0.006).

CONCLUSIONS

The strategy to select DR-matched, PRA-negative de novo cadaveric transplant recipients for a CNI-avoidance protocol was not successful. The incidence of acute rejection was unacceptable high even though anti-CD25 antibody induction as well as initial higher mycophenolate mofetil doses (3 g/day) were applied, and renal function was significantly lower in the CNI-avoidance patients at 1 year. Other strategies need to be examined for avoidance of CNI's in the early posttransplant period.

Change From Cyclosporine to Combination Therapy of Mycophenolic Acid With the New Sphingosine-1-phosphate Receptor Agonist, KRP-203, Prevents Host Nephrotoxicity and Transplant Vasculopathy in Rats

BACKGROUND

Replacement of calcineurin inhibitor (CI) with anti-metabolic agents in transplant patients with CI-induced nephrotoxicity is performed clinically and improves renal function, but increases the risk of rejection. We investigated whether the change from cyclosporine (CsA) to a limited dose of mycophenolic acid (MPA) together with a new sphingosine-1-phosphate (S1P) receptor agonist, KRP-203, is sufficient to prevent both transplant vasculopathy and CsA-induced nephrotoxicity.

METHODS

Orthotopic aortic transplantation was conducted in a high-responder rat combination of Dark Agouti (DA; major histocompatibility complex [MHC] haplotype RT-1a) to Lewis (RT-1(l)). After CsA administration (15 mg/kg/day) for 2 weeks, the recipients were divided into the following treatment groups for 6 weeks: MPA (10 mg/kg); KRP-203 (KRP; 1 mg/kg); and MPA + KRP. Serum creatinine (Cr), arteriolar hyalinosis and expression of transforming growth factor (TGF)-beta1 in the recipient kidney were examined as parameters indicating nephrotoxicity. Intimal hyperplasia was assessed by vascular occlusion, and graft-infiltrated cells were semi-quantitatively evaluated histologically and then characterized immunohistochemically.

RESULTS

Continuous CsA treatment attenuated intimal hyperplasia and cell infiltration (2.9 +/- 0.3% and 0.4 +/- 0.1; p < 0.01 vs vehicle), but increased Cr and hyalinosis (0.43 +/- 0.03 mg/dl and 57.2 +/- 0.4%; p < 0.01) with upregulated TGF-beta1. Replacement of CsA by MPA or KRP treatment alone improved nephrotoxicity, but worsened intimal hyperplasia and cell infiltration. Conversion to MPA + KRP treatment prevented nephrotoxicity (Cr, 0.32 +/- 0.02 mg/dl; hyalinosis, 5.6 +/- 1.3%; p < 0.01 vs CsA) and markedly suppressed intimal hyperplasia and cell infiltration (3.6 +/- 1.2% and 1.0 +/- 0.3; p = not significant vs CsA), with reduced T-cell infiltrates in the graft.

CONCLUSIONS

Changing from CsA to a combined therapy of MMF with S1P agonist is a promising strategy in clinical transplantation to overcome CI-induced nephrotoxicity and chronic rejection.

Preliminary experience with mycophenolate mofetil for preservation of renal function in cardiac transplant patients with documented cyclosporine nephrotoxicity

BACKGROUND

Cyclosporine (CyA) has positively impacted on the outcome of cardiac transplantation; however, the nephrotoxicity associated with CyA has been a major drawback.

METHODS

In an effort to reduce exposure to CyA and possibly alleviate its nephrotoxic effects, we undertook a therapeutic strategy to switch cardiac transplant patients with biopsy-proven CyA nephrotoxicity from azathioprine (AZA) to mycophenolate mofetil (MMF) with subsequent CyA dose reduction or elimination.

RESULTS

MMF was substituted for AZA in five cardiac transplant patients (four males; mean age, 60 +/- 6 years old; average time from transplant was 7 +/- 3 years) who had biopsy proven evidence of CyA nephrotoxicity, and in whom CyA dose was reduced (3/5) or discontinued (2/5). At the time of the therapeutic intervention, four patients had an average serum creatinine of 230 +/- 62 micromol/L and one patient had just been started on haemodialysis (HD). During an average follow-up period of 42 months, the slope of the inverse serum creatinine significantly improved in three patients and continued to deteriorate in one patient. The patient on HD could be transiently taken off HD. However, he developed a severe episode of cardiac rejection requiring antirejection therapy and increase in the dose of CyA. The patient was subsequently returned back on HD.

CONCLUSION

In this preliminary report, we show that AZA to MMF switch with subsequent CyA dose reduction or discontinuation may slow down the progression of kidney disease in some patients. However, the patients should be followed closely for evidence of cardiac rejection.

Calcineurin-inhibitor-sparing immunosuppressive protocols

Calcineurin inhibitors (CNI) have played an important role in improving graft survival. However, the balance between preventing immunologic allograft losses and the management of CNI-related nephrotoxicity is still an issue in renal transplantation. There are three major CNI-sparing strategies. CNI MINIMIZATION: The advent of mycophenolate mofetil (MMF) allows cyclosporine (CsA) reduction to ameliorate renal function in patients with chronic renal allograft dysfunction, without increasing acute rejection rates. In combination with mTOR inhibitors, very low CNI levels may be sufficient to prevent acute rejection. However, in this association, CNI nephrotoxicity is magnified by pharmacokinetic interaction. CNI WITHDRAWAL: CNI withdrawal has been attempted in regimens containing MMF or sirolimus (SRL). Introduction of MMF in patients with chronic allograft nephropathy (CAN) followed by CNI withdrawal resulted in stabilization or improvement of renal function and hypertension profile, although there is some risk of acute rejection. In regimes based on SRL, CNI withdrawal is a safety strategy, achieving a sustained improvement of renal function, histology, and graft survival. There is not consensus at all whether MMF should be added or not in patients converted from CNI to mTOR inhibitor. CNI AVOIDANCE: Polyclonal-based regimens with MMF and steroids have shown acceptable acute rejection rates, but high rates of cytomegalovirus (CMV) and opportunistic infections. Conversely, anti-IL-2R in combination with MMF and steroids resulted in 50% incidence of acute rejection, thus suggesting that CNI avoidance is not feasible in a regimen based on MMF. Alternatively, a protocol based on anti-IL-2R induction therapy combined with SRL, MMF, and prednisone has shown an efficient prevention of acute rejection, higher creatinine clearance and lower rate of CAN in comparison with a group treated with CNI. New strategies using costimulation blockade may help in the development of safe CNI-free regimens. In summary, in renal transplantation the new immunosuppressive medications have made feasible old aspirations such as minimization, withdrawal, or even avoidance of CNI.

In vitro prevention of cyclosporin-induced cell contraction by mycophenolic acid

Nephrotoxicity is a major side-effect of cyclosporin A (CsA), which induces a vasoconstrictive response in vascular smooth muscle and mesangial cells. Mycophenolic acid (MPA) is used in combination with low-dose CsA to reduce nephrotoxicity. We previously demonstrated that MPA affected mesangial cell contractile response to angiotensin II or KCl. Aims of the present study were to evaluate if MPA can prevent CsA-induced contraction of human mesangial and aortic smooth muscle cells (ASMC). Using a morphoquantitative approach, we evidenced that pretreatment with MPA (1 microM) prevented the reduction of cell area induced by CsA within 30 min in both cell types. We then compared the expression of three main cytoskeleton proteins: tubulin, alpha-smooth actin (SMA) and basic calponin, in ASMC and in mesangial cells treated with MPA and/or CsA. CsA alone did not significantly change the expression level of these proteins neither in mesangial cells nor in ASMC. MPA decreased the expression level of tubulin in both mesangial cells and ASMC. Surprisingly, MPA, which stimulated SMA and calponin expression in mesangial cells, exerted an inhibitory effect on both contractile protein expression in ASMC. In conclusion, our results evidenced opposite effects of MPA on calponin and SMA protein expression in ASMC and in mesangial cells, despite similar antiproliferative properties, suggesting that sarcomeric protein expression is controlled by different intracellular mechanisms in mesangial and smooth muscle cells. However, MPA interferes in both cell types with the constrictive properties CsA, which may partially explain the protective effects of MPA against CsA nephrotoxicity.

Chronic allograft nephropathy and mycophenolate mofetil introduction in paediatric renal recipients

Mycophenolate mofetil (MMF) introduction with concurrent reduction in calcineurin inhibitors has been shown to be beneficial in chronic allograft nephropathy (CAN) in adults. MMF was introduced to 19 children with CAN 26.3+/-5.8 (range 3.1-82.6) months after transplantation. Patients were followed up for a mean of 13.2+/-2.9 (range 1.2-51.1) months. The mean initial MMF dose was 660+/-56 mg/m2 per day, increased to 1,042+/-73 mg/m2 per day a year later. Cyclosporin was reduced from 138+/-10 mg/m2 per day at MMF introduction, to 116+/-15 mg/m2 per day at 6 months and 107+/-24 mg/m2 per day at 1 year. Six months prior to MMF introduction GFR deteriorated by -32.7+/-7.3 ml/min per 1.73 m2 per year. Six months after the introduction of MMF, GFR improved by +26.2+/-7.1 ml/min per 1.73 m2 per year (P <0.001). The introduction of MMF significantly reduced both the graft rejection rate (P=0.01) and systolic blood pressure (P=0.01), without a significant change in antihypertensive treatment. Haematological parameters did not significantly differ before and after MMF introduction. The introduction of MMF in paediatric renal transplant recipients with CAN may cause a significant improvement in GFR in both the short-term and the long-term and may well have a beneficial effect on systolic blood pressure. MMF has the potential to enable CNI-sparing protocols to be adopted.

Mycophenolate mofetil substitution for cyclosporine a in renal transplant recipients with chronic progressive allograft dysfunction: the "creeping creatinine" study

BACKGROUND

This study determined whether cyclosporine A (CsA)-treated renal allograft recipients with deteriorating renal function ("creeping creatinine") secondary to chronic allograft nephropathy (CAN) benefit from the addition of mycophenolate mofetil (MMF) to their immunosuppressive regimen, followed by withdrawal of CsA.

METHODS

In a controlled, open, multicenter study, CsA-treated renal allograft recipients with progressively deteriorating renal function were randomized to have their CsA discontinued with the concomitant addition of MMF to their regimen (group A) or to continue treatment with CsA (group B). The primary endpoint was the response rate over the 6-month period after withdrawal of CsA in group A or the equivalent time in group B. Response was defined as a stabilization or reduction of serum creatinine (SCr), as evidenced by a flattening or positive slope of the 1/SCr plot and no graft loss. Secondary endpoints included the incidence of acute rejection, graft and patient survival, and changes in selected metabolic parameters.

RESULTS

The response rate in the primary intent-to-treat population (n=122) was 58% (36/62) in group A versus 32% (19/60) in group B (P=0.0060). The corresponding percentages of responders in the per-protocol population (n=107) were 60% (36/60) and 26% (12/47), respectively (P=0.0008). There were no acute rejections in group A during the study period. Patients in this group also experienced a significant decrease in total cholesterol.

CONCLUSIONS

In patients with progressively deteriorating renal function secondary to CAN, addition of MMF followed by withdrawal of CsA results in a significant improvement in transplant function without the risk of acute rejection.

Erythrocyte sodium lithium countertransport in renal transplant recipients with mycophenolate mofetil and low-dose cyclosporine

Hypertension, a common complication after renal transplantation, has many potential etiologies. Erythrocyte sodium lithium countertransport (Na/LiCT) is a sensitive membrane protein that has been observed to be abnormal in several hypertension-related diseases. We have shown that the kinetics of Na/LiCT were abnormal in renal transplant recipients treated with usual dose of cyclosporine (CsA). We postulated that CsA might be a cause of post-renal transplantation hypertension. There is evidence showing that the severity of CsA nephrotoxicity is dependent on the dose. Mycophenolate mofetil (MMF) may allow CsA dose reduction without increasing the risk of rejection. We studied the impact of CsA dose reduction in association with MMF on the kinetics of erythrocyte Na/LiCT in renal transplants. In 15 renal allograft recipients, 2 g/d MMF were introduced and the CsA dose reduced to reach whole-blood levels between 70 and 100 ng/mL within 1 month. CsA doses and levels, renal function parameters, blood pressure, and the kinetics of Na/LiCT were evaluated before and 6 months after CsA dose reduction. Overall, renal transplant recipients with usual doses of CsA showed a lower Km with a higher Vmax/Km ratio for erythrocyte Na/LiCT than normal controls (Km, 40 +/- 4 vs 74 +/- 11; P <.05; Vmax/Km, 10.2 +/- 1.7 vs 6.1 +/- 0.9; P <.05). After 6 months of CsA dose reduction, the Km and Vmax/Km of Na/LiCT were similar to those of normal controls (Km, 66 +/- 8 vs 74 +/- 11; P >.05; Vmax/Km, 5.7 +/- 1.2 vs 6.1 +/- 0.9; P >.05). These results demonstrate that reduction of CsA dose in combination with MMF may improve the kinetics of Na/LiCT and lessen the long-term side effects of CsA without increasing the risk of rejection.

Crohn's-like changes in the colon due to mycophenolate?

OBJECTIVE

Mycophenolate mofetil (MMF) is used for prevention of allograft rejection in kidney transplant patients. A subset of patients suffers from chronic diarrhoea of unknown origin. The aim of the study was to investigate the effect of MMF on the colonic mucosa.

MATERIALS AND METHODS

Colonic mucosal biopsies from 24 kidney transplant patients receiving MMF and presenting with chronic diarrhoea were analysed using routine stainings and immunohistochemistry for Ki67 and E-cadherin. Results were compared with a control group of 19 kidney transplant patients not receiving MMF. In all patients routine clinical and laboratory investigations were performed in order to explain the diarrhoea.

RESULTS

In 11 patients, the diarrhoea seemed to be of infectious origin. Furthermore, 19/24 of MMF-patients showed characteristic histological alterations of the mucosa that were Crohn's disease-like: discontinuous crypt architectural distortion, increased epithelial mucin secretion, mildly active inflammation and focal presence of dilated and inflamed crypts. Ki67 staining was abnormal in 6/24 MMF patients but also in 4/19 control patients. E-Cadherin staining was normal in most MMF and control patients.

CONCLUSIONS

Diarrhoea following MMF treatment is frequently infectious in origin and associated with morphological changes with a Crohn's-like pattern in the colonic mucosa in a subset of patients. MMF does not induce major alteration in the proliferative compartment of colonic epithelium. The diarrhoea is not associated with altered E-cadherin expression in the colonic epithelium.

Effect of immunosuppressive agents on long-term survival of renal transplant recipients: focus on the cardiovascular risk

In the control of acute rejection, attention is being focused more and more on the long-term adverse effects of the immunosuppressive agents used. Since cardiovascular disease is the main cause of death in renal transplant recipients, optimal control of cardiovascular risk factors is essential in the long-term management of these patients. Unfortunately, several commonly used immunosuppressive drugs interfere with the cardiovascular system. In this review, the cardiovascular adverse effects of the immunosuppressive agents currently used for maintenance immunosuppression are thoroughly discussed. Optimising immunosuppression means finding a balance between efficacy and safety. Corticosteroids induce endothelial dysfunction, hypertension, hyperlipidaemia and diabetes mellitus, and impair fibrinolysis. The use of corticosteroids in transplant recipients is undesirable, not only because of their cardiovascular effects, but also because they induce such adverse effects as osteoporosis, obesity, and atrophy of the skin and vessel wall. Calcineurin inhibitors are the most powerful agents for maintenance immunosuppression. The calcineurin inhibitor ciclosporin (cyclosporine) not only induces these same adverse effects as corticosteroids but is also nephrotoxic. Tacrolimus has a more favourable cardiovascular risk profile than ciclosporin and is also less nephrotoxic. It has little or no effect on blood pressure and serum lipids; however, its diabetogenic effect is more prominent in the period immediately following transplantation, although at maintenance dosages, the diabetogenic effect appears to be comparable to that of ciclosporin. The diabetogenic effect of tacrolimus can be managed by reducing the dose of tacrolimus and early corticosteroid withdrawal. The effect of tacrolimus on endothelial function has not been completely elucidated. The proliferation inhibitors azathioprine and mycophenolate mofetil (MMF) have little effect on the cardiovascular system. Yet, indirectly, by inducing anaemia, they may lead to left ventricular hypertrophy. MMF is an attractive alternative to azathioprine because of its higher potency and possibly lower risk of malignancies. Sirolimus also induces anaemia, but may be promising because of its antiproliferative features. Whether the hyperlipidaemia induced by sirolimus counteracts its beneficial effects is, as yet, unknown. It may be combined with MMF, however, initial attempts resulted in severe mouth ulcers.

Low-Dose Cyclosporine with Mycophenolate Mofetil Induces Similar Calcineurin Activity and Cytokine Inhibition as does Standard-Dose Cyclosporine in Stable Renal Allografts

One strategy to minimize nephrotoxicity in maintenance immunosuppression in renal transplantation is reduction of cyclosporine (CsA) with addition of mycophenolate mofetil (MMF). This approach seems safe, but concern exists about whether it yields adequate immunosuppression in the long term. Thus, we investigated the pharmacodynamic response to CsA in stable renal allografts treated with standard CsA (n = 17, CsA-C0h > or = 125 ng/mL) and low CsA plus MMF (n = 18 CsA-C0h <100 ng/mL). Patients treated with MMF without CsA (n = 13) and healthy subjects (n = 7) were used as controls. We observed that inhibition of calcineurin (CN) activity in peripheral blood mononuclear cells (PBMC), as well as interleukin (IL)-2 and interferon (IFN)-gamma production were similar in Standard-CsA and Low-CsA+MMF groups. Moreover, addition of MMF to a low CsA dose regime improved the correlation between CsA-C2h and both CN activity and IL-2 production. Thus, our results suggest that MMF could be synergistic with the pharmacodynamic effect of low CsA in maintenance immunosuppression.

Conversion from cyclosporine A to mycophenolate mofetil protects recipient kidney and prevents intimal hyperplasia in rat aortic allografts

BACKGROUND

Recent studies have demonstrated that complete conversion from cyclosporine A (CsA) to mycophenolate mofetil (MMF) prolongs graft survival in patients undergoing clinical organ transplantation. We investigated the effects of conversion from CsA to MMF on recipient kidneys and transplant arteriosclerosis in a rat aortic allograft model as a high responder combination.

METHODS

DA (MHC haplotype, RT1a) rat abdominal aortic grafts were orthotopically transplanted into Lewis (RT1l) rats. The recipients were divided into four oral treatment groups: (1) vehicle group, (2) CsA group (15 mg/kg/day), (3) CsA/MMF40 group (conversion from CsA 15 mg/kg/day to MMF 40 mg/kg/day on day 14), and (4) CsA/MMF20 group (conversion from CsA 15 mg/kg/day to MMF 20 mg/kg/day on day 14). On day 28 after transplantation, the rats were sacrificed and the hematoserological parameters were analyzed. The grafted aortas and recipient kidneys also were evaluated histologically and immunohistochemically.

RESULTS

The CsA group developed serological renal dysfunction, arteriolar hyalinosis, and apoptosis in the recipient kidneys, whereas the CsA/MMF40 and CsA/MMF20 groups did not. In the vehicle group, we observed remarkable intimal hyperplasia and marked inflammatory cell infiltration including macrophages and T cells. In the CsA group, intimal hyperplasia was evident without infiltration of macrophages or T cells. In the CsA/MMF40 and CsA/MMF20 groups, intimal hyperplasia was abrogated, while adventitial infiltration of and adhesion to the endothelium by macrophages and T cells occurred.

CONCLUSIONS

Conversion from CsA to MMF protected recipient kidneys and prevented transplant arteriosclerosis. However, insufficient immunosuppression by MMF might reactivate immune cells. This conversion therapy has preventive potential in transplant patients with CsA-associated nephrotoxicity and transplant arteriosclerosis.

Clinical experience of mycophenolate mofetil in the treatment of chronic allograft nephropathy in kidney transplantation: Three-year follow-up

BACKGROUND

Mycophenolate mofetil (MMF) in conjunction with calcineura antagonists has been shown to prevent acute rejection in renal allograft recipients. Its role in treatment of chronic rejection or allograft nephropathy is still controversial. We initiated the study to investigate the effect of adding MMF to a cyclosporine plus prednisolone regimen in renal recipients with chronic allograft nephropathy.

MATERIALS AND METHODS

We retrospectively studied 36 patients with chronic allograft nephropathy, defined clinically as increased of serum creatinine, proteinuria, and hypertension. Renal function, cyclosporine level, renal biopsy, and renal scan were regularly done as indicated. MMF was added to 20 recipients after initial treatment with cyclosporine and prednisolone. The other 16 recipients were managed without adding MMF. Serum creatinine was monitored for 3 years.

RESULTS

The demographic characteristics of the patients in the two groups were comparable. The average dose of prednisolone was unchanged throughout the study and the trough level of cyclosporine was maintained in the range of 100 to 150 ng/mL. The serum creatinine decreased initially in the group on MMF, but renal function deteriorated progressively after 6 months. There was a difference in serum creatinine between the two groups but this did not reach statistical significance.

CONCLUSION

MMF therapy tender to improve renal function initially but did not attenuate significantly the impairment in chronic allograft nephropathy.

Impact of chronic allograft nephropathy and subsequent modifications of immunosuppressive therapy on late graft outcomes in renal transplantation

BACKGROUND

Chronic allograft nephropathy (CAN) is the leading cause of organ failure in renal transplant recipients. We retrospectively evaluated the impact of varying immunosuppression in CAN patients on long-term graft survival.

METHODS

We retrospectively analysed 158 cyclosporin (CsA)-treated renal transplant recipients with biopsy-proven CAN with follow-up of >1 year. Immunosuppression remained unchanged in 75 (NOVAR) and was modified in 83 patients (VAR). In 36.1% of VAR patients, it was increased; in 63.8%, the addition of other immunosuppressants was associated with a 20% reduction in or withdrawal of CsA. A regression model, for creatinine clearance (CrCl) slope analysis after therapy variation, and Cox's analysis were applied.

RESULTS

In VAR patients, two-phase regression did not show a correlation between the inflection point in the CrCl slope and treatment variation. Changing immunosuppression gave a borderline advantage in long-term graft survival compared with NOVAR (P = 0.088). In univariate analysis, severe histological lesions, proteinuria >0.5 g/day and CrCl <25 ml/min at biopsy correlated with poor graft outcome (P = 0.0009). In multivariate analysis, only proteinuria and low CrCl remained significative. Stratifying histological lesions in relation to therapy variation showed that severe lesions significantly decreased survival in both VAR and NOVAR groups; however, the highly negative impact of severe lesions in NOVAR patients on graft survival [relative risk (RR) 3.602] was reduced in VAR patients (RR 1.951), with a 10 year graft survival since biopsy of 0.16 vs 0.34 (P = 0.0001).

CONCLUSIONS

In transplant patients with CAN, variation of immunosuppression can reduce the negative impact of severe chronic lesions.

Preservation of renal function during maintenance therapy with cyclosporine

During the last 20 years the management of cyclosporine (CsA) has improved due to the introduction of microemulsion technology, C2 monitoring, and combination with other new immunosuppressants. All these modifications have reduced the incidence of biopsy-proven acute rejection episodes to approximately 10%. However despite the wide experience, there are unanswered questions regarding CsA monitoring after the first year. Available clinical and histological data suggest that the therapeutic range to avoid nephrotoxicity or underimmunosuppression during the maintenance period is rather narrow. Furthermore, the combination of CsA with new immunosuppressants may modify the target CsA levels. Although the utility of C2 levels during the first year has been well characterized, there are few data on its utility for maintenance therapy, particularly the therapeutic range for C2 levels in patients receiving different immunosuppressive combinations. Since serum creatinine does not precisely reflect the progression of chronic allograft nephropathy, the efficacy of C2 monitoring during the maintenance period must be assessed not only by means of evaluation of renal function, but also histologic assessment using protocol biopsies.

Cyclosporine renal dysfunction

Cyclosporine (CsA), introduced as an immunosuppressive agent in the 1980s, quickly become the first-line treatment in organ transplantation. However, these improvements were associated with an increased incidence of renal dysfunction. CsA causes histopathological changes in renal transplants that are often difficult to distinguish from other processes, especially chronic allograft nephropathy. Enhanced angiotensin II, transforming growth factor-beta, and vascular endothelial growth factor expression together with down-regulation of nitric oxide synthesis may play roles in chronic CsA nephropathy. Efforts have recently focused upon protocols that minimize the risk of CsA nephrotoxicity while preserving low rates of acute rejection. Four types of CsA-sparing studies have emerged from recent clinical experience: (1) conversion studies in which a nonnephrotoxic drug is substituted to allow CsA reduction, (2) minimal CsA exposure studies in which reduced CsA doses are combined with nonnephrotoxic drugs, (3) withdrawal studies in which CsA is completely discontinued at some time after transplantation, and (4) CsA-free studies in which the drug is completely avoided from the time of transplantation. Monitoring of CsA immunosuppression according to C2 blood levels, which better correlate with the area under the time-concentration curve than trough concentrations, should reduce the risk for toxicity; however, the most appropriate target range has not yet been clearly established. Because of interindividual differences in CsA absorption and susceptibility to renal dysfunction, the current therapeutic drug monitoring should be supplemented with pharmacogenetic information on genetic variability of relevant genes for pharmacokinetic parameters and therapeutic targets. This approach may guide choices for immunosuppressants for particular patients, with low toxicity. Thus, despite of 20 years of its history, CsA renal dysfunction remains an important clinical challenge.

Efficacy of mycophenolate mofetil combined with very low-dose cyclosporine microemulsion in long-term liver-transplant patients with renal dysfunction

BACKGROUND

Cyclosporine (CsA)-induced renal dysfunction is common after liver transplantation. We evaluated the efficacy of tapering CsA to a very low dose and introducing mycophenolate mofetil (MMF) in long-term liver-transplant recipients with renal dysfunction. In addition, we assessed the impact of this strategy on calcineurin inhibition and on transforming growth factor (TGF)-beta levels.

METHODS

We prospectively enrolled 19 adult, long-term (>1 year) liver-transplant recipients with a decreased creatinine clearance greater than 25% compared with the first month posttransplant. MMF was introduced, and CsA was tapered to 25 mg twice daily. Calcineurin inhibition and TGF-beta were measured at baseline and 3 months thereafter.

RESULTS

The CsA dose was tapered over 13+/-3 weeks. At 1-year follow-up, serum creatinine decreased from 141+/-24 to 105+/-22 micromol/L (P=0.002), creatinine clearance increased from 53+/-9 to 71+/-19 ml/min (P=0.02), and glomerular filtration rate increased from 40+/-13 to 64+/-18 mL/min (P=0.002). The incidence of acute rejection was 29%. Antihypertensive medications were discontinued in 71% of the patients. Although CsA levels decreased significantly, serum TGF-beta did not differ from normal controls, and calcineurin inhibition remained stable. The incidence of gastrointestinal side-effects and leukopenia was 18% and 24%, respectively.

CONCLUSION

In long-term liver-transplant recipients with renal dysfunction, the introduction of MMF followed by tapering of CsA to a very low dose resulted in a significant improvement in renal function. However, this strategy maybe associated with a risk of acute rejection. The clinical pertinence of measuring serum TGF-beta levels and calcineurin inhibition remains to be determined.

The impact of cyclosporine dose reduction with or without the addition of rapamycin on functional, molecular, and histological markers of chronic allograft nephropathy

BACKGROUND

Overexposure to cyclosporine is a risk factor for chronic allograft nephropathy (CAN) and dose reduction has been advocated. The purpose of this study was to determine the impact of adding the non-nephrotoxic immunosuppressant, rapamycin, after cyclosporine dose reduction in renal-allograft recipients with CAN.

METHODS

Thirty-one patients with biopsy-confirmed CAN were prospectively randomized to receive a 40% cyclosporine dose reduction with (rapamycin, n=16) or without (control, n=15) the addition of rapamycin 2 mg/day. Renal function and side-effect parameters were assessed. Patients had renal allograft biopsies taken at recruitment and after 6 months. Glomeruli were isolated from these and underwent total mRNA extraction followed by RT-PCR-ELISA to assess transforming growth factor-beta1, collagen III, TIMP-1, TIMP-2, and matrix metalloproteinase-2 expression. Samples were also stained with Sirius red and the percentage interstitial volume fraction quantified by computerized histomorphometric analysis. Data are presented as mean (+/-SD).

RESULTS

Patient characteristics and cyclosporine trough levels after dose reduction (rapamycin 68 [+/-21] vs. control 56 [+/-19] ng/mL, P=NS) were similar in both groups. Rapamycin patients had a significant fall in Cr-51 radioisotope glomerular filtration rate (31.6 [+/-8.9] to 27.3 [+/-8.6] mL/min, P<0.01) that was not significant in controls (29.5 [+/-10.4] to 27.0 [+/-8.0] mL/min, P=NS). Transforming growth factor-beta1 expression fell over time in control but remained constant in rapamycin patients. Conversely collagen III expression increased over the 6-month follow-up in rapamycin patients but not in controls. Both had comparable increases in TIMP-1 and matrix metalloproteinase-2 but only rapamycin patients developed a significant increase in TIMP-2. Sirius red-stained interstitial volume fraction fell over the study in controls (15.3-11.2%, P=0.06) but not in rapamycin patients (16.2-16.3%, P=NS).

CONCLUSION

Rapamycin (2 mg/day) did not improve functional, molecular, or histological outcome in patients with CAN after cyclosporine dose reduction. Further studies involving larger numbers of patients are necessary to confirm these findings.

Reversibility of chronic cyclosporine nephropathy in rats after withdrawal of cyclosporine

Renal interstitial inflammation is an important factor in the pathogenesis of chronic cyclosporin A (CsA) nephropathy. We studied the expression of the chemoattractant osteopontin (OPN) and the relationship between OPN expression and tubulointerstitial injury in a rat model of chronic CsA nephropathy. Chronic CsA nephropathy was induced in Sprague-Dawley rats by administering CsA (15 mg/kg sc) for 5 wk and then withdrawing it for 5 or 10 wk. Renal function, histopathology (arteriolopathy, ED-1-positive cells, and tubulointerstitial fibrosis), renin-angiotensin system (RAS) activity, and OPN expression were observed during the follow-up period. Renal function deteriorated in CsA-treated rats, with the development of typical histopathology and activation of RAS. After CsA withdrawal, these parameters were significantly reversed (all P < 0.05). The upregulation of OPN mRNA and protein expression seen in CsA-treated rat kidneys was decreased 5 wk after CsA withdrawal and was further decreased after 10 wk. Of note, OPN mRNA expression correlated with the number of infiltrating macrophage (r = 0.651, P < 0.01) and tubulointerstitial fibrosis (r = 0.729, P < 0.01). These findings suggest that OPN expression and macrophage infiltration decrease after long-term CsA withdrawal in rats with established chronic CsA nephropathy, and this is closely associated with recovery from renal injury.

Influence of the new immunosuppressive combinations on arterial hypertension after renal transplantation

Arterial hypertension is highly prevalent after renal transplantation and may contribute to the risk of cardiovascular disease. Also, arterial hypertension has been reported to be an independent risk factor for graft failure. Immunosuppressive drugs such as corticosteroids, cyclosporine and tacrolimus may be important contributing factors to post-transplant hypertension. Recent data from multicenter trials and from conversion studies (cyclosporine to tacrolimus) suggest that renal transplant patients under tacrolimus-based therapy showed less arterial hypertension compared with cyclosporine treated patients. New immunosuppressive drugs, including mycophenolate mofetil and rapamycin, are not nephrotoxic and they do not have any hypertensive effect. New immunosuppressive combinations including mycophenolate mofetil in a triple therapy regimen (associated with corticosteroids and cyclosporine) can reduce blood pressure so that corticosteroids can be stopped or cyclosporine reduced or even eliminated. Non-nephrotoxic regimens using rapamycin (sirolimus) as basic immunosuppression, associated with azathioprine or mycophenolate mofetil, could reduce the incidence of post-transplant arterial hypertension. Also, in renal transplant patients initially immunosuppressed with rapamycin, cyclosporine and corticosteroids, after the elimination of CSA, a lower blood pressure is achieved. In summary, new protocols with mycophenolate mofetil and/or rapamycin may permit several combinations that offer important alternatives to classical immunosuppressive regimens to reduce the incidence and clinical impact of arterial hypertension after renal transplantation.

Cyclosporine withdrawal and mycophenolate mofetil treatment effects on the progression of chronic cyclosporine nephrotoxicity

BACKGROUND

Recent clinical trials of mycophenolate mofetil (MMF) in chronic allograft nephropathy (CAN) demonstrated that the dose of cyclosporine A (CsA) is one of the critical factors in determining graft function in CAN, but the effect of MMF on chronic CsA nephropathy is undetermined. We undertook this study to evaluate the effect of MMF on CsA-induced nephrotoxicity in an animal model of chronic CsA nephropathy.

METHODS

In the first experiment, Sprague-Dawley rats on a low-salt diet were treated with CsA (7.5 mg/kg per day) for 10 weeks, or were treated with CsA for five weeks and then MMF (20 mg/kg per day) was administered five weeks later. In the second experiment, rats were treated with CsA for five weeks, and CsA was then withdrawn for five weeks with or without MMF treatment. Renal function, histologic parameters (tubulointerstitial fibrosis, arteriolopathy, ED-1-positive cells, renin-positive glomeruli, TUNEL-positive cells) and the expression of osteopontin and transforming growth factor (TGF)-beta1 mRNA expressions were compared for different treatment groups.

RESULTS

CsA-treated rats showed decreased renal function and increased histologic parameters compared with the vehicle (VH)-treated rats. The addition of MMF did not improve these parameters compared with the CsA-treated rats. With CsA withdrawal, renal function and histologic parameters were significantly improved compared with the CsA-treated rats, and MMF treatment after CsA withdrawal further improved the histologic parameters. At the molecular level, the addition of MMF did not decrease the expression of osteopontin and transforming growth factor-beta1 (TGF-beta1) mRNAs, which were increased in the CsA-treated rat kidney. With CsA withdrawal, the expression of both mRNAs was significantly decreased compared with the CsA group, and a further decrease was observed with MMF treatment after CsA was withdrawn.

CONCLUSION

The combined treatment of CsA and MMF does not prevent the development of chronic CsA nephrotoxicity, but MMF treatment after CsA withdrawal does improve chronic CsA nephrotoxicity. This finding provides a rationale for MMF treatment in chronic CsA nephrotoxicity.

Cyclosporin: an updated review of the pharmacokinetic properties, clinical efficacy and tolerability of a microemulsion-based formulation (neoral)1 in organ transplantation

Cyclosporin is a lipophilic cyclic polypeptide immunosuppressant that interferes with the activity of T cells chiefly via calcineurin inhibition. The original oil-based oral formulation of this drug (Sandimmun)l was characterised by high intra- and interpatient pharmacokinetic variability, with poor bioavailability in many patients; a novel microemulsion formulation (Neoral)1 was therefore developed to circumvent these problems. Studies show increases, attributable chiefly to improved absorption in patients who absorb the drug only poorly from the original formulation, in mean systemic exposure to cyclosporin with the microemulsion, with no clinically significant differences in tolerability or drug interaction profiles. Cyclosporin microemulsion is at least as effective as the oil-based formulation in renal, liver and heart transplant recipients, with trends towards decreased incidence of acute rejection with the microemulsion formulation in some (statistically significant in a few) trials. Cyclosporin microemulsion and tacrolimus appear to have similar efficacy in preventing acute rejection episodes in most renal, pancreas-kidney, liver and heart transplant recipients. However, there are indications of superior efficacy for tacrolimus in some trials, particularly in the prevention of severe acute rejection and in Black transplant recipients. Current 12-month data also indicate equivalent efficacy of sirolimus in renal transplantation. Conversion from the oil-based to microemulsion formulation in stable renal, liver and heart transplant recipients is achievable with no change in acute rejection rates. The addition of an anti-interleukin-2 receptor monoclonal antibody and/or mycophenolate mofetil to cyclosporin microemulsion plus corticosteroids decreases rates of acute rejection; corticosteroid withdrawal without increased acute rejection rates was also achieved on the addition of these agents in some trials. Pharmacoeconomic analyses have shown savings in direct healthcare costs in kidney or liver transplantation when cyclosporin microemulsion is used in preference to the oil-based formulation, although studies incorporating indirect costs or expressing costs in terms of therapeutic outcomes are currently unavailable.

CONCLUSIONS

The introduction of cyclosporin microemulsion has consolidated the place of the drug as a mainstay of therapy in all types of solid organ transplantation; research into optimisation of outcomes through more effective therapeutic monitoring in patients receiving this formulation is ongoing. Several novel immunosuppressants have been introduced in recent years: further clinical and pharmacoeconomic research will be needed to clarify the relative positioning of these agents, particularly with respect to specific patient groups. Other new drugs (basiliximab/daclizumab and mycophenolate mofetil) offer particular advantages when used in combination with cyclosporin.