Treatment Of Chronic Allograft Nephropathy Research Articles

Validation of multiparametric MRI by histopathology after nephrectomy: a case study

ObjectivesRenal multiparametric MRI (mpMRI) is a promising tool to monitor renal allograft health to enable timely treatment of chronic allograft nephropathy. This study aims to validate mpMRI by whole-kidney histology following transplantectomy.Materials and methodsA patient with kidney transplant failure underwent mpMRI prior to transplantectomy. The mpMRI included blood oxygenation level-dependent (BOLD) MRI, T1 and T2 mapping, diffusion-weighted imaging (DWI), 2D phase contrast (2DPC) and arterial spin labeling (ASL). Parenchymal mpMRI measures were compared to normative values obtained in 19 healthy controls. Differences were expressed in standard deviations (SD) of normative values. The mpMRI measures were compared qualitatively to histology.ResultsThe mpMRI showed a heterogeneous parenchyma consistent with extensive interstitial hemorrhage on histology. A global increase in T1 (+ 3.0 SD) and restricted diffusivity (− 3.6 SD) were consistent with inflammation and fibrosis. Decreased T2 (− 1.8 SD) indicated fibrosis or hemorrhage. ASL showed diminished cortical perfusion (− 2.9 SD) with patent proximal arteries. 2DPC revealed a 69% decrease in renal perfusion. Histological evaluation showed a dense inflammatory infiltrate and fibrotic changes, consistent with mpMRI results. Most interlobular arteries were obliterated while proximal arteries were patent, consistent with ASL findings.DiscussionmpMRI findings correlated well with histology both globally as well as locally.

Correlation between shear wave velocity of renal parenchyma and TGF-β1 in chronic allograft nephropathy

Objective To evaluate the change of shear wave velocity (SWV) of renal parenchyma and serum level of transforming growth factor beta 1 (TGF-β1) in the patients with chronic allograft nephropathy (CAN), and further evaluate the correlation between them. Methods A total of 60 patients with chronic allograft nephropathy confirmed by renal biopsy were selected and divided into three groups according to the degree of interstitial fibrosis and tubular atrophy of the transplanted kidney: group C1 (renal cortex involvement 50%, n=20). 30 renal transplant recipients with normal renal function were enrolled for control group. The SWV of the renal were measured by virtual touch tissue quantification (VTQ) and the serum level of TGF-β1 were detected by enzyme linked immunosorbent assay (ELISA) in each group. Results Compared with control group, the SWV and serum TGF-β1 in case groups were significantly higher (P<0.05). SWV measured values: group C3 was the highest, group C2 was middle one and group C1 was the lowest (P<0.05). Statistically significant difference in serum TGF-β1 was observed among these three groups (P<0.05). The renal SWV and serum TGF-β1 had a significant positive correlation (r=0.631, P<0.05). Conclusions Both renal SWV and serum TGF-β1 increase as CAN progressed, which have high value in the diagnosis and treatment of CAN. Key words: Kidney transplantation; Kidney diseases; Ultrasonography, doppler, color; Transforming growth factor beta1

Differences in Tfh Cell Response between the Graft and Spleen with Chronic Allograft Nephropathy

The aim of this study was to investigate follicular helper T (Tfh) cell response and its difference between renal graft and spleen in a rat renal transplantation model undergoing chronic allograft nephropathy (CAN). Orthotopical kidney transplantations were performed on Fischer (F344) rats and transplanted to Lewis rats, using syngeneic Lewis–Lewis grafts as controls. Tissue samples were collected at 8 weeks posttransplantation. The status of Tfh cell response was assessed by measuring the levels of transcription factor B-cell lymphoma 6 (Bcl-6), interleukin-21 (IL-21), chemokine receptor type 5 (CXCR5), and B-cell-activating factor belonging to the TNF family (BAFF). Tfh cell response was upregulated in both renal graft and spleen of the CAN group compared to the control group. However, Tfh cell response of the spleen was weaker than that of the graft, which was possibly related to the upregulation of splenic Treg activation. Also, the difference between two tissues was partially associated with the different expressions of tristetraprolin (TTP)/IL-10. Our data help improve our understanding of the role of Tfh cell response in the body with CAN and may provide a valuable clue for better treatment of CAN.

Impact of immunosuppressive agents on the expression of indoleamine 2,3-dioxygenase, heme oxygenase-1 and interleukin-7 in mesangial cells.

Chronic allograft nephropathy (CAN) is a major cause of graft loss following kidney transplantation and may result from the interactions of various immune and non-immune factors. The aim of the present study was to establish an in vitro model of glomerular mesangial cell injury in order to examine the gene expression levels of indoleamine 2,3-dioxygenase (IDO), heme oxygenase-1 (HO-1) and interleukin-7 (IL-7) in mesangial cells during the healing process as well as to investigate the effects of various immunosuppressants on the expression of these genes. The HBZY-1 glomerular mesangial cell line was pre-treated in vitro with cytochalasin B for 2 h to induce reversible damage. Following the pre-treatment, the HBZY-1 cells were divided into five groups: Blank control group, cyclosporine A (CsA) group, tacrolimus (Tac) group, mycophenolate mofetil (MMF) group and rapamycin (RAPA) group. After treating the mesangial cells with each immunosuppressive drug for 6, 12 or 24 h, the mRNA and protein expression levels of IDO, HO-1 and IL-7 were examined using reverse transcription quantitative polymerase chain reaction (RT-qPCR), western blot and immunohistochemical analyses. The results showed that expression levels of HO-1 were significantly upregulated in response to treatment with CsA, FK506, RAPA and MMF, whereas the expression levels of IL-7 were markedly downregulated by treatment with the above immunosuppressants. CsA, FK506 and MMF significantly enhanced the expression levels of IDO, whereas RAPA exhibited no apparent effect on IDO. The present study may contribute to the understanding of the pathogenesis of CAN and provide novel strategies for the prevention and treatment of CAN.

Biological pathways and potential targets for prevention and therapy of chronic allograft nephropathy.

Renal transplantation (RT) is the best option for patients with end-stage renal disease, but the half-life is limited to a decade due to progressive deterioration of renal function and transplant failure from chronic allograft nephropathy (CAN), which is the leading cause of transplant loss. Extensive research has been done to understand the pathogenesis, the biological pathways of fibrogenesis, and potential therapeutic targets for the prevention and treatment of CAN. Despite the advancements in the immunosuppressive agents and patient care, CAN continues to remain an unresolved problem in renal transplantation. The aim of this paper is to undertake a comprehensive review of the literature on the pathogenesis, biological pathways of RT fibrogenesis, and potential therapeutic targets for the prevention and therapy of CAN.

Editorial introductions

Editorial introductions

Cover Picture: Proteomics – Clinical Applications 7–8/11

AbstractA line in the sand: Late summer starting point for workflow designSecurity is handled by the rising tide. Remily‐Wood et al. developed a procedure for high‐throughput quantitative analysis for cancer research and clinical studies. The process begins with some bench and library work to define the target to be quantitated by determining amino acid sequences, isoforms, post‐translational modifications, and Western blots. Data go into QuAD, a JavaServer supplying other resources (Swiss‐Prot, etc.) and summary statistics of the target proteins. Target proteins and pathways must have ≥3 distinctive peptides, quantitative assays and have cultured cell line equivalents. Heavy isotope‐labeled synthetic peptides and cultured cell sequences are used to follow the LC‐Multiple Reaction Monitoring. The molecular weight equivalent SDS‐PAGE region is excised for screening peptides after in‐gel digestion. The screening conditions use minimal amounts of labeled peptides.Remily‐Wood, E. R. et al., Proteomics Clin. Appl. 2011, 5, 383–396.Getting your ducks in a row: A tough herding jobFrench medical practices require testing all newborns for sickle cell disease. There is a standard method for the test – isoelectric focusing (IEF) followed by HPLC on a cation exchange column. The HPLC ducks can be readily automated and labor costs minimized, but not so for IEF. It is tedious, uses expensive materials and is generally disliked in the lab, especially when many samples need to be run. Hachani et al. report on the development of a MALDI‐MS method that deals with most of problems. Previous research work had been incomplete for a variety of reasons. The new method used the same sample cards, a robotic commercial sample prep method, and automated analysis of samples using a MALDI‐TOF/TOF instrument. Failures of the new method against IEF were informative – most were premature or heterozygous neonatal infants. Conclusion: automated herding of 1000 samples/day looks feasible.Hachani, J. et al., Proteomics Clin. Appl. 2011, 5, 405–414.Double or nothing for the kidney?It is a sucker's bet on some streets in New York and serious business for patients waiting for a kidney transplant. Chronic allograft nephropathy (CAN) is the leading cause of kidney graft failure in the first year after transplant, being responsible for a 50–80% loss rate. The ability to reduce the failure rate by early recognition and treatment of CAN would markedly increase the number of kidneys available. Johnston et al. report here an improved urine protein marker pattern that can distinguish normal from CAN urine protein patterns. The principal element of the pattern (SELDI‐TOF‐MS hardware) was the amount of β2 microglobulin (11.7 kDa). A single β2 microglobulin point is insufficiently discriminating so further work will have to be done in a more complex setting.Johnston, O. et al., Proteomics Clin. Appl. 2011, 5, 422–431.

In this issue

AbstractA line in the sand: Late summer starting point for workflow designpp. 383–396Security is handled by the rising tide. Remily‐Wood et al. developed a procedure for high‐throughput quantitative analysis for cancer research and clinical studies. The process begins with some bench and library work to define the target to be quantitated by determining amino acid sequences, isoforms, post‐translational modifications, and Western blots. Data go into QuAD, a JavaServer supplying other resources (Swiss‐Prot, etc.) and summary statistics of the target proteins. Target proteins and pathways must have ≥3 distinctive peptides, quantitative assays and have cultured cell line equivalents. Heavy isotope‐labeled synthetic peptides and cultured cell sequences are used to follow the LC‐Multiple Reaction Monitoring. The molecular weight equivalent SDS‐PAGE region is excised for screening peptides after in‐gel digestion. The screening conditions use minimal amounts of labeled peptides. magnified imageGetting your ducks in a row: A tough herding jobpp. 405–414French medical practices require testing all newborns for sickle cell disease. There is a standard method for the test – isoelectric focusing (IEF) followed by HPLC on a cation exchange column. The HPLC ducks can be readily automated and labor costs minimized, but not so for IEF. It is tedious, uses expensive materials and is generally disliked in the lab, especially when many samples need to be run. Hachani et al. report on the development of a MALDI‐MS method that deals with most of problems. Previous research work had been incomplete for a variety of reasons. The new method used the same sample cards, a robotic commercial sample prep method, and automated analysis of samples using a MALDI‐TOF/TOF instrument. Failures of the new method against IEF were informative – most were premature or heterozygous neonatal infants. Conclusion: automated herding of 1000 samples/day looks feasible. magnified imageDouble or nothing for the kidney?pp. 422–431It is a sucker's bet on some streets in New York and serious business for patients waiting for a kidney transplant. Chronic allograft nephropathy (CAN) is the leading cause of kidney graft failure in the first year after transplant, being responsible for a 50–80% loss rate. The ability to reduce the failure rate by early recognition and treatment of CAN would markedly increase the number of kidneys available. Johnston et al. report here an improved urine protein marker pattern that can distinguish normal from CAN urine protein patterns. The principal element of the pattern (SELDI‐TOF‐MS hardware) was the amount of β2 microglobulin (11.7 kDa). A single β2 microglobulin point is insufficiently discriminating so further work will have to be done in a more complex setting. magnified image

Therapeutic effect of low-dose aspirin on chronic allograft nephropathy in renal recipient rats

Objective To observe the effect of low-dose aspirin on allogeneic chronic allograft nephropathy in renal recipient rats and the possible mechanisms.Methods Chronic allograft nephropathy model of rats were established and the recipient rats were randomly divided into 2 groups with 10 in each group.Cyclosporine A (5 mg/kg) was administered as a basic treatment one day before surgery to prevent and treat acute rejection.Aspirin therapy group was given oral aspirin (5 mg/kg) daily,and control group were given oral saline 2 ml/d.Animals were sacrificed 8 weeks after operation and the serum creatinine,urea nitrogen levels were determined.Renal histomorphology and immunohistochemistry approaches were used to examine TGF-β1 expression.Results The severity of pathological lesion,increase of serum creatinine and blood urea nitrogen levels,and expression of fibrosis associated factor TGF-β1 in aspirin therapy group were significantly slighter than those of the saline control group(P0.05).Conclusion Low-dose aspirin in addition to routine anti-rejection treatment can be used for treatment of chronic allograft nephropathy in rats,which might be associated with the decreased expression of anticoagulation factor TGF-β1.

The pathogenesis and treatment of chronic allograft nephropathy

Despite improvements in immunosuppressive therapy, long-term allograft survival after kidney transplantation remains as low as 50%. Chronic allograft nephropathy (CAN) is a major cause of late graft loss in renal transplant recipients. The histopathologic signs of CAN-interstitial fibrosis, tubular atrophy, glomerulopathy and vasculopathy-are nonspecific; therefore, the 2007 Banff classification dispensed with the term CAN in favor of 'interstitial fibrosis and tubular atrophy without evidence of any specific etiology'. In this Review, however, the term CAN is used to describe a clinical syndrome that is characterized by progressive decline in renal function from 3 months after transplantation, accompanied by the development of proteinuria and hypertension. The pathogenesis of CAN is complex and incompletely understood, and involves several immunological and non-immunological factors. We discuss the contributory roles of acute rejection, donor age, anti-human-leukocyte-antigen antibodies, calcineurin inhibitor nephrotoxic effects, viral infection, hypertension and hyperlipidemia. The prevention and treatment of CAN needs multidisciplinary strategies. Early detection by means of protocol biopsy and calculation of glomerular filtration rate is the first step, followed by management of modifiable risk factors.

Treatment of Chronic Allograft Nephropathy at Late Stages Using Everolimus or FTY720 in Combination With Cyclosporine

Objective In this study, we used combined treatment with cyclosporine (CsA)/everolimus (EVR) or CsA/FTY720 to affect ongoing chronic allograft nephropathy (CAN) compared with monotherapy with EVR or FTY720. Background CAN is an important cause of renal allograft loss. Immunosuppressive therapy is based on calcineurin inhibitors, which are associated with nephrotoxicity and decreasing graft function. Thus, alternative treatment regimens, including new immunosuppressants, such as EVR or FTY720, are of interest. We asked whether the combination of CsA with EVR or FTY720 ameliorated the development of CAN more effectively than monotherapy with EVR and/or FTY720 during the later stages of CAN. Methods Kidneys from Fisher rats were orthotopically transplanted into Lewis rats. Animals received CsA (1.5 mg/kg/d) for the first 10 days after transplantation. Animals were assigned to 6 groups: EVR (0.5 mg/kg/d), FTY720 (0.5 mg/kg/d), CsA (1.5 mg/kg/d), CsA+EVR (1.5 + 0.5 mg/kg/d), CsA+FTY720 (1.5 + 0.5 mg/kg/d), and vehicle (VEH). Treatment started at week 20. The observation period ended after 28 weeks. Results Treatment with EVR and FTY720 reduced proteinuria and glomerulosclerosis, suppressed lymphocyte and macrophage infiltration, and resulted in a greater number of apoptotic tubular and interstitial cells compared with the combined treatment groups and controls. Conclusion Although EVR and FTY720 monotherapy delayed the progression of CAN, their combination with CsA had no beneficial effect.

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.

Longitudinal analysis of chronic allograft nephropathy: Clinicopathologic correlations

Loss of the allograft from chronic allograft nephropathy and death of the patient from vascular, malignant, or infective disease are the major problems in renal transplantation today. Protocol biopsy of the long-term kidney has provided new data with which to develop strategies for prevention and treatment of chronic allograft nephropathy. Two series of long-term protocol biopsies are reviewed. In the first, renal biopsies were obtained at time 0, and at 3 months and 12 months, and the recipients of the renal allografts were followed up for up to 15 years. In the second, the kidneys of recipients of simultaneous pancreas kidney transplants were biopsied annually for 10 years, and the results correlated with clinical events. Chronic allograft nephropathy is caused by acute and chronic immune-mediated damage, as well as by chronic calcineurin inhibitor nephrotoxicity. Both immune and nonimmune mechanisms exacerbate pre-existing donor disease and ischemia-reperfusion injury. Established interstitial fibrosis and arteriolar hyalinosis lead to progressive glomerular sclerosis and eventual loss of the graft. Protocol biopsies have shown that clinical parameters of renal function underestimate the severity of chronic graft damage. Strategies for preventing or treating chronic renal allograft dysfunction and subsequent graft loss must better control rejection and simultaneously avoid nephrotoxicity.

Immunosuppressive treatment and progression of histologic lesions in kidney allografts

Renal transplantation is the best therapeutic option for patients with end-stage renal disease. Although short-term results are excellent, long-term graft survival has not improved substantially in recent times. Chronic allograft nephropathy (CAN) and death with a functioning graft are the most important causes of graft loss. Recent evidence shows that nephrotoxicity of calcineurin inhibitors contributes to CAN, and the introduction of non-nephrotoxic drugs such as mycophenolate mofetil (MMF) and mammalian target of rapamycin inhibitors may provide new immunosuppressive strategies to improve long-term results after renal transplantation. MMF decreases the risk of developing chronic allograft failure and is useful for treating established CAN, because it has a beneficial effect on allograft fibrosis. Treatment with sirolimus (SRL), a basic immunosuppressive drug given in association with MMF, may offer better renal function, decrease the prevalence of CAN, and downregulate expression of genes responsible for the progression of CAN than treatment with cyclosporine A (CsA). SRL also permits an early elimination of CsA from SRL-CsA-steroid regimens and shows better renal function and improved renal histology without risk of rejection. Notably, this approach improves graft survival at 4 years. Further multicenter studies are needed to determine whether both approaches produce similar results by comparing immunosuppression caused by SRL-based and tacrolimus (TAC)-based treatments. Because TAC is the most commonly used anticalcineurin drug, it is important to compare the effects of steroid-TAC-SRL treatment with and without elimination of TAC. Finally, although caution is needed, the use of non-nephrotoxic immunosuppressive treatment may change the natural history of CAN.

Rapamycin for Treatment of Chronic Allograft Nephropathy in Renal Transplant Patients

Chronic allograft nephropathy (CAN) represents the main cause of renal allograft loss after 1 yr of transplantation. Calcineurin inhibitor (CNI) use is associated with increased graft expression of profibrotic cytokines, whereas rapamycin inhibits fibroblast proliferation. The aim of this randomized, prospective, open-label, single-center study was to evaluate the histologic and clinical effect of rapamycin on biopsy-proven CAN. Eighty-four consecutive patients who had biopsy-proven CAN and received a transplant were randomized to receive either a 40% CNI reduction plus mycophenolate mofetil (group 1; 50 patients) or immediate CNI withdrawal and rapamycin introduction with a loading dose of 0.1 mg/kg per d and a maintaining dose aiming at through levels of 6 to 10 ng/ml (group 2; 34 patients). The follow-up period was 24 mo. At the end of follow-up, 25 patients (group 1, 10 patients; group 2, 15 patients) underwent a second biopsy. CAN lesions were graded according to Banff criteria. alpha-Smooth muscle actin (alpha-SMA) protein expression was evaluated in all biopsies as a marker of fibroblast activation. Graft function and Banff grading were superimposable at randomization. Graft survival was significantly better in group 2 (P = 0.0376, chi2 = 4.323). CAN grading worsened significantly in group 1, whereas it remained stable in group 2. After 24 mo, all group 1 biopsies showed an increase of alpha-SMA expression at the interstitial and vascular levels (P < 0.001); on the contrary, alpha-SMA expression was dramatically reduced in group 2 biopsies (P = 0.005). This study demonstrates that rapamycin introduction/CNI withdrawal improves graft survival and reduces interstitial and vascular alpha-SMA expression, slowing down the progression of allograft injury in patients with CAN.

The clinic diagnosis and treatment of chronic allograft nephropathy

目的 探讨慢性移植肾肾病(CAN)的临床诊断及治疗特点.方法回顾性分析32例CAN临床资料.经移植肾穿刺活检诊断CAN 32例.全部病例予减少环孢素A(CsA)剂量,浓度控制在(100±40)ng/ml上下,应用血管紧张素Ⅱ受体拮抗剂或血管紧张素转化酶抑制剂,限制蛋白质饮食,控制高血压.结果2个月后28例治疗有效,血肌酐恢复到(135±32)μmol/L(与术后比较,P＞0.05,n=28),其中20例蛋白尿消失,移植肾活检复查证实CAN无进展恶化.无效4例,治疗前肌酐已达195～286 μmol/L,移植肾活检复查显示CAN进展恶化.结论移植肾穿刺活检是诊断CAN的主要手段,血肌酐达到160～180 μmol/L时予干预治疗预后较好。

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.

PROTECTIVE EFFECTS OF FTY720 ON CHRONIC ALLOGRAFT NEPHROPATHY BY REDUCING LATE LYMPHOCYTIC INFILTRATION

P783 Aims: Chronic allograft nephropathy (CAN) still belongs to the important causes of late allograft loss. No effective treatment of CAN has been established so far. FTY720, a novel immunosuppressant, reducing lymphocytes in the periphery and increasing lymphocytes in the lymphatic organs, prevents acute renal allograft rejection. However, the significance of lymphocyte infiltration especially during CAN, and whether a reduction of lymphocyte infiltration influences the progression of CAN, is not clear yet. Here we analyzed the potential of FTY720 to reduce the number of graft infiltrating lymphocytes and whether apoptosis could play a role in such an effect even at late stages after kidney transplantation. Methods: Fisher (F344) rat kidneys were orthotopically transplanted into Lewis recipients followed by nephrectomy of the own kidneys. Animals received an initial 10-day course of cyclosporin A (1.5mg/kg/day). FTY720 (0.5mg/kg/d) or vehicle were administered to recipients either from weeks 12 to 24 or from 20 to 24 after transplantation. Kidneys were obtained 24 weeks after transplantation for histological, immunohistological and molecular analysis. Results: FTY720, either initiated at 12 or 20 weeks after transplantation, reduced urinary protein excretion, and significantly ameliorated glomerulosclerosis, interstitial fibrosis, tubular atrophy, and intimal proliferation of graft arteries at 24 weeks after transplantation. Furthermore, FTY720 markedly suppressed lymphocyte infiltration and decreased mRNA levels of IL-10, TGF-β, and PDGF-B but enhanced the number of apoptotic lymphocytes in the grafts with respect to controls. Conclusions: FTY720 ameliorated CAN even at advanced stages. Furthermore, our data suggest that a reduction of graft infiltrating lymphocytes contributed to this effect. Apart from the known lymphocyte depleting effect in the periphery related to the increased homing of lymphocytes to the lymphatic tissue this could also be related to an increased number of lymphocyte apoptosis in the graft.

Mycophenolate mofetil-induced reversal of glomerular filtration loss in children with chronic allograft nephropathy.

Mycophenolate mofetil (MMF) has been used for the treatment of chronic allograft nephropathy (CAN) in adults with inconsistent results, but data in children are rare. To evaluate its impact on advanced CAN, we studied changes in glomerular filtration rate (GFR) and the correlation of GFR changes to histology. Thirty-six children (13.1+/-3.6 years) with a progressive decline in GFR of 16.9+/-12.4 mL/min per 1.73 m2/year and biopsy confirmed CAN 4.3+/-2.9 years after transplantation were studied. MMF was added to conventional immunosuppression (IS) consisting of cyclosporine (CsA) and prednisolone (n=26) or tacrolimus (n=1) or replaced azathioprine in triple IS (n=9). Alterations of GFR were correlated to histologic guidelines according to the Banff chronic score (BCS). One year after conversion, 22 (61%) children showed a rise in GFR (7.5+/-6 mL/min per 1.73 m2), 8 (22%) remained stable, and 6 (17%) showed a further decline of GFR (7.4+/-2 mL/min per 1.73 m2). Mean CsA trough levels were 114 ng/mL before and 98 ng/mL 1 year after conversion. MMF side effects required dose reduction in 14 children. Children responding to MMF with increasing GFR showed a trend toward less fibrosis, less incidence of vasculopathy, and transplant glomerulopathy in the initial biopsy but had a similar incidence of borderline tubulitis compared with the other groups. Cotreatment with MMF reversed the progressive loss of GFR in approximately two thirds of children with CAN for at least 1 year. Less chronicity signs in histology seem to indicate a more favorable response to treatment.

Review of the antiproliferative properties of mycophenolate mofetil in non-immune cells.

Mycophenolate mofetil (MMF), the prodrug ofmycophenolic acid (MPA), is a selective, non-competitive and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH) and of the type II isoform in particular. IMPDH is the rate-limiting enzyme in the de novo biosynthesis of guanosine nucleotides. MMF strongly inhibits both T- and B lymphocyte proliferation and has been used in the prevention of acute and chronic allograft rejection since the mid 1990s. Recent evidence, however, suggests that MMF is also capable of inhibiting the proliferation of non-immune cells. In various cell lines, i.e. smooth muscle cells, renal tubular cells and mesangial cells, MPA reduced or even abrogated proliferation in response to proliferative stimuli. Furthermore, data from our own laboratory demonstrate a dose-dependent inhibition of dermal fibroblast proliferation by MPA. In animal studies, MMF ameliorated renal lesions in immune-mediated disease, i.e. in the anti-thy 1.1 model and experimental lupus nephritis, but was also effective in non-immune-mediated renal damage in the rat remnant-kidney model. These observations prompted several investigators to study the effects of MMF in proliferating (renal) disease of non-immune origin in humans. MMF significantly reduced proteinuria in minimal-change disease and focal segmental glomerulosclerosis. In addition, MMF showed beneficial effects in the treatment of chronic allograft nephropathy and calcineurin inhibitor toxicity through reduction of immune- and non-immune-mediated renal damage. MMF is well tolerated and has proven to be a relatively safe drug causing only minor bone marrow suppression. Taken together, there is a growing body of evidence pointing to therapeutic applications of MMF other than immunosuppression, in particular the prevention of fibrosis.