Tacrolimus exposure in the real world: an analysis from the Mycophenolic acid Observational REnal transplant study.

Tacrolimus exposure and renal function data to 36 months post-transplant were analyzed from the prospective, observational Mycophenolic acid Observational REnal transplant (MORE) registry in which de novo kidney transplant patients were managed according to local practice. Tacrolimus trough (C0 ) concentration at month 12 was stratified as low (<6 ng/mL), moderate (6-8 ng/mL), or high (>8 ng/mL) in 724 patients. Estimated glomerular filtration rate (eGFR) was stratified as low (<60 mL/min/1.73 m(2) ) or high (≥60 mL/min/1.73 m(2) ). High tacrolimus C0 (>8 ng/mL) was observed in 47.7%, 34.1%, 26.8%, and 26.7% of patients at baseline and months 12, 24, and 36, respectively. Biopsy-proven acute rejection was similar to month 36 regardless of tacrolimus C0 category at month 12. Tacrolimus C0 >8 ng/mL vs. <6 ng/mL at month 12 was predictive of low eGFR at month 24 (p = 0.023) with a nonsignificant trend at month 36 (p = 0.085). Infections (p < 0.013) and BK virus infection (p < 0.001) were most frequent in the low tacrolimus C0 cohort. Neutropenia was most frequent in the high tacrolimus C0 category (p = 0.010). In conclusion, over a quarter of patients were exposed to high tacrolimus C0 to 36 months post-transplant. Tacrolimus exposure did not affect rejection risk, but tacrolimus C0 >8 ng/mL at month 12 was predictive of subsequent low eGFR compared to C0 <6 ng/mL.

Outcomes in ethnic minority renal transplant recipients receiving everolimus versus mycophenolate: comparative risk assessment results from a pooled analysis.

BACKGROUND: Everolimus (EVR) has demonstrated good efficacy after renal transplantation. Racial disparities in clinical outcomes after de novo renal transplantation are well documented; whether the efficacy of EVR varies based on recipient ethnicity is unknown. We conducted a comparative risk assessment of EVR by ethnicity. METHODS: Data on 2004 renal transplant recipients from three EVR studies were pooled to identify the impact of ethnicity on efficacy outcomes across EVR dosing groups and control groups. Ethnic groups compared were African Americans, non-U.S. blacks, Asians, Hispanics, and Caucasians. EVR groups received either 1.5 or 3 mg per day, with either standard-dose cyclosporine or reduced-dose cyclosporine. Control groups received mycophenolic acid (MPA) with standard-dose cyclosporine. Composite efficacy failure endpoint was graft loss, death, biopsy-proven acute rejection, or lost to follow-up. Adjusted odds ratios were calculated using a logistic regression model. RESULTS: The proportion of renal transplant recipients who met the composite endpoint was African Americans (46%), non-U.S. black (35%), Caucasian (31%), Hispanic (28%), and Asian (25%). The odds of meeting the composite endpoint were significantly (P=0.0001) greater for African Americans versus Caucasians but did not differ among the other ethnic groups (ethnic groups were only compared with Caucasians). EVR and MPA were associated with similar efficacy among each of the ethnic groups. CONCLUSION: In this pooled data analysis in more than 2000 renal transplant recipients, EVR versus MPA resulted in similar composite endpoint incidence events across ethnicities. Consistent with previously published data, African Americans had poorer clinical outcomes. EVR is efficacious regardless of ethnicity.

Association of clinical events with everolimus exposure in kidney transplant patients receiving reduced cyclosporine.

BACKGROUND: The association between clinical events and everolimus exposure in patients receiving reduced-exposure calcineurin inhibitor therapy is poorly explored. METHODS: In a pre-planned, descriptive analysis of data from a randomized controlled trial, events were correlated with everolimus trough concentrations in 556 newly transplanted kidney transplant patients receiving everolimus with reduced-exposure cyclosporine (CsA) and steroids. Influence of everolimus exposure on clinical events was stratified according to predefined time-normalized concentrations. RESULTS: The incidence of treated biopsy-proven acute rejection and graft loss at month 12 was highest in patients with everolimus <3 ng/mL (36.4% and 28.6%, respectively, vs. 9.1-15.3% and 0.9-5.0% with higher concentration ranges). A higher mortality rate was observed in patients with an everolimus trough concentration ≥ 12 ng/mL (10.0% vs. 1.7-5.6% with lower concentration ranges). The lowest rates of renal dysfunction (defined as poor renal function [estimated GFR, serum creatinine] or proteinuria), wound healing events, peripheral edema, new-onset diabetes mellitus, hypercholesterolemia and hypertriglyceridemia were generally observed with everolimus trough concentration in the range 3-8 ng/mL and CsA <100 ng/mL. Proteinuria occurred most frequently in patients with very low or very high everolimus trough concentrations. CONCLUSIONS: These results support an exposure-response relationship between clinical events and everolimus trough concentrations in kidney transplant patients receiving reduced-exposure CsA.

Effect of donor kidney volume on recipient outcome: does the "dose" matter?

BACKGROUND: The effect of donor kidney volume on recipient kidney function has not been fully evaluated. METHODS: We performed a prospective analysis of 125 consecutive living kidney donor/recipient pairs. Donor kidney volume was calculated from pretransplantation computed tomography angiograms using a three-dimensional computerized volume method. Cortical volume was calculated from arterial phase and total volume from delayed phase. Because weight is a surrogate marker for metabolic demands, we looked at the "volume dose" by calculating the ratio of donor kidney volume to recipient weight. Recipient kidney function was assessed by calculating the estimated glomerular filtration rate (eGFR) using the Chronic Kidney Disease Epidemiology Collaboration formula. Logistic regression models were used to evaluate odds of developing eGFR of <60 mL/min per 1.73m(2) (eGFR<60) at 12 months. RESULTS: Because cortical and total volumes were correlated (R=0.734, P<0.001), we used total kidney volume to evaluate the dose effect. The mean donated volume dose (SD) was 2.13 (0.62) mL/kg. The mean recipient eGFR at 12 months was 63.6 (17.3) mL/min per 1.73 m, and it correlated with volume dose (r=0.341, P<0.001). Compared with the lowest tertile, those in the highest tertile of donor kidney volume to recipient weight had lower odds ratio of developing eGFR of less than 60 mL/min per 1.73 m(2) (odds ratio, 0.23; 95% confidence interval, 0.07-0.81) in a multivariate logistic regression model. Spline regression suggested that a volume dose greater than 2.5 mL/kg was associated with lowest risk of eGFR of less than 60 mL/min per 1.73 m(2) at 12 months. CONCLUSIONS: Donor kidney volume dosing is an important determinant of recipient graft outcomes and may predict recipient kidney function in kidney transplantation.

Low-dose fluconazole prophylaxis in kidney transplant recipients receiving tacrolimus.

BACKGROUND: The use of prophylactic antifungal therapy is suggested after kidney transplantation. However, efficacy of low-dose (50 mg) oral fluconazole and its effect on tacrolimus trough levels in patients maintained on tacrolimus and mycophenolic acid, with or without corticosteroids, is unknown. METHODS: A retrospective analysis to evaluate efficacy was performed in 305 kidney transplant recipients. An additional analysis to evaluate the fluconazole-tacrolimus drug interaction was performed in 103 patients. Complete tacrolimus area under the curve measurements were also performed in seven patients to further evaluate this drug interaction. RESULTS: The incidence of fungal infections was very low (0.6%, n = 2). The average tacrolimus trough level at the time of discontinuation and one wk after stopping fluconazole was unchanged (11.69 ± 3.18 and 11.15 ± 3.69 ng/mL, p = 0.145, n = 103). Tacrolimus trough levels on and off of fluconazole in a subgroup of patients continued on corticosteroids, was not significantly different (p = 0.952) but was significantly lower after fluconazole discontinuation if corticosteroids were withdrawn (p = 0.037). However, data from complete tacrolimus pharmacokinetics in the corticosteroid withdrawal group demonstrated no clinically significant differences. CONCLUSION: Low-dose, once daily oral fluconazole is effective antifungal prophylaxis after kidney transplantation without significant effects on tacrolimus trough levels or overall exposure.

Role of cellular cholesterol in pharmacologic preconditioning with cyclosporine in experimental kidney transplantation.

BACKGROUND/AIMS: Ischemia reperfusion injury in the early posttransplant period affects immediate graft function and late allograft dysfunction. Recently, we showed that pharmacologic preconditioning with a calcineurin inhibitor improved transplant outcomes in rat syngeneic kidney transplantation. There is also evidence that cellular cholesterol content increases after many types of renal injury. METHODS: In this study, we looked at the effect of cyclosporine (CsA) on the donor kidney free cholesterol (FC) content in this model. Donor rats were pretreated with one dose of CsA 10 mg/kg administered 24 h or 7 days before being subjected to 2 h cold ischemia and then transplanted. RESULTS: Pharmacologic preconditioning with CsA significantly improved renal function and histology and increased donor kidney FC content. On the other hand, fluvastatin co-administration with CsA abrogated that beneficial effect in association with a decrease in donor kidney FC content. CONCLUSION: CsA preconditioning leads to better outcomes in kidney transplantation and is associated with up-regulation of renal FC content. The latter may then contribute to acquired cytoresistance, possibly by stabilizing the plasma membrane. Thus, use of statins around the time of transplantation may need to be evaluated until further studies are conducted to determine the clinical relevance of this observation.

Post-transplant increased levels of serum sCD30 is a marker for prediction of kidney allograft loss in a 5-year prospective study.

BACKGROUND: Levels of sCD30 represent a biomarker for early outcome in kidney transplantation. The purpose of this study was to determine the role of sCD30 levels for prediction of graft loss in the late post-transplant period. METHODS: Sera were collected immediately pre-transplant and yearly thereafter for up to 5-year post-transplant in 37 primary renal transplant recipients. Levels of serum sCD30 were tested using a fluorescent microsphere assay. RESULTS: Levels of sCD30 significantly decreased after transplantation and remained normal in 34 patients without graft loss up to 5-year post-transplant. Elevated levels of serum sCD30 preceded the increase of serum creatinine in patients with subsequent graft loss. CONCLUSIONS: Elevated levels of serum sCD30 post-transplant might be a marker for predicting subsequent graft loss in the post-transplant period.

No occurrence of de novo HLA antibodies in patients with early corticosteroid withdrawal in a 5-year prospective randomized study.

The purpose of this study was to determine the effect of early corticosteroid cessation on the occurrence of de novo human leukocyte antigen (HLA) antibody posttransplant. Renal transplant recipients (n=37) were randomized to early corticosteroid withdrawal at day 7 posttransplant (n=21 patients), or to chronic steroids (n=16), all in combination with thymoglobulin as induction agent, tacrolimus and mycophenolic acid as maintenance therapy. To establish the time course of HLA antibody appearance, sera collected pretransplant and for up to 5 years posttransplant were screened for the appearance of HLA antibodies. In this 5-year longitudinal study, only one patient in the control group developed a de novo donor-specific HLA antibody. We conclude that renal transplant recipients on steroid withdrawal by the end of week 1 are not at higher risk for developing HLA antibodies compared with a standard steroid regimen up to 5 years posttransplant.

Donor preconditioning with a calcineurin inhibitor improves outcome in rat syngeneic kidney transplantation.

Ischemia-reperfusion injury (IRI) in the early posttransplant period affects immediate graft function and late allograft dysfunction. This study determines the influence of pharmacologic preconditioning with a calcineurin inhibitor on IRI in a syngeneic F344 rat kidney transplant model. Donor rats were pretreated with one dose of cyclosporine (10 mg/kg) or tacrolimus (1 mg/kg) administered at 24 hr or 7 days before being subjected to 2 hr of cold ischemia and then transplanted. Pharmacologic preconditioning significantly improved renal function, as assessed by serum creatinine and inulin clearance, and histologic score versus vehicle-treated rats. There were no differences between cyclosporine and tacrolimus in the measured outcomes. This renoprotective effect, although not complete, was seen with only one dose of calcineurin inhibitor, and the effect was sustained for at least 7 days before IRI. This approach may represent a viable pharmacologic intervention to decrease IRI at the time of organ transplantation.

Optimizing tacrolimus therapy in the maintenance of renal allografts: 12-month results.

BACKGROUND: The determination of optimal tacrolimus (TAC) trough levels is needed to prevent adverse effects of calcineurin inhibitors. METHODS: Stable transplant recipients currently receiving cyclosporine (CsA) were assigned randomly (1:1:1) to continue CsA (target trough level of 50-250 ng/mL); or convert to "reduced" TAC (target trough level 3.0-5.9 ng/mL) or "standard" TAC (target trough level 6.0-8.9 ng/mL). RESULTS: At 12 months, there was a significant improvement in renal function in the reduced TAC versus CsA group with lower serum creatinine (P=0.004) and cystatin C (P<0.001), and higher estimated creatinine clearance (P=0.017). However, there were no statistically significant differences in any renal parameter in the standard TAC versus CsA group. Total and low-density lipoprotein cholesterol were significantly reduced in both TAC groups versus the CsA group (P<0.001). Patient and graft survival and episodes of biopsy-confirmed acute rejection were similar for all treatment groups, and no statistically significant differences were observed between groups in the incidence of new-onset diabetes or cardiac conditions, or in the prevalence of hyperglycemia, hypertension, or hyperlipidemia among patients who did not have these conditions at baseline. Alopecia developed more commonly among TAC-treated patients than CsA-treated patients (P<0.001). CONCLUSIONS: Compared with CsA continuation, conversion to reduced TAC target trough concentrations resulted in significantly improved renal function without increasing the risk of rejection. Conversion to TAC, regardless of target concentration, resulted in improved serum lipid profiles in kidney transplant recipients at 12 months.

Factors affecting kidney-transplant outcome in recipients with lupus nephritis.

BACKGROUND: Factors associated with outcome in renal transplant recipients with lupus nephritis have not been studied. METHODS: Using the data from the United States Renal Data System of patients transplanted between January 1, 1995 through December 31, 2002 (and followed through December 31, 2003) (n = 2882), we performed a retrospective analysis of factors associated with long-term death-censored graft survival and recipient survival. RESULTS: The number of pretransplant pregnancies incrementally increased the risk of graft failure [hazard ratio (HR) 1.54, p < 0.05] in the entire subgroup of females and in the subgroup of recipients aged 25-35 yr. Recipient and donor age had an association with both the risk of graft failure (HR 0.96, p < 0.001; HR 1.01, p < 0.005) and recipient death (HR 1.04, p < 0.001; HR 1.01, p < 0.05). Greater graft-failure risk accompanied increased recipient weight (HR 1.01, p < 0.001); African Americans compared with whites (HR 1.55, p < 0.001); greater Charlson comorbidity index (HR 1.17, p < 0.05); and greater panel reactive antibody (PRA) levels (HR 1.06, p < 0.001). Pretransplant peritoneal dialysis as the predominant modality had an association with decreased risk of graft failure (HR 0.49, p < 0.001), while prior transplantation was associated with greater risk of graft failure and recipient death (HR 2.29, p < 0.001; HR 3.59, p < 0.001, respectively) compared with hemodialysis (HD). The number of matched human leukocyte antigens (HLA) antigens and living donors (HR 0.92, p < 0.05; HR 0.64, p < 0.001, respectively) was associated with decreased risk of graft failure. Increased risk of graft failure and recipient death was associated with nonuse of calcineurin inhibitors (HR 1.89, p < 0.005; HR 1.80, p < 0.005) and mycophenolic acid (MPA) (including mycophenolate mofetil and MPA) or azathioprine (HR 1.41, p < 0.05; HR 1.66, p < 0.01). Using both cyclosporine and tacrolimus was associated with increased risk of graft failure (HR 2.09, p < 0.05). Using MPA is associated with greater risk of recipient death compared with azathioprine (HR 1.47, p < 0.05). CONCLUSION: In renal transplant recipients with lupus nephritis, multiple pregnancies, multiple blood transfusions, greater comorbidity index, higher body weight, age and African American race of the donor or recipient, prior history of transplantation, greater PRA levels, lower level of HLA matching, deceased donors, and HD in pretransplant period have an association with increased risk of graft failure. Similarly, higher recipient and donor age, prior transplantations, and higher rate of pretransplant transfusions are associated with greater risk of recipient mortality. Using neither cyclosporine nor tacrolimus or using both (compared with tacrolimus) and neither MPA nor azathioprine (compared with azathioprine) was associated with increased risk of graft failure and recipient death. Using MPA is associated with greater risk of recipient death compared with azathioprine. Testing these results in a prospective study might provide important information for clinical practice.

Conversion from cyclosporine to tacrolimus in patients at risk for chronic renal allograft failure: 60-month results of the CRAF Study.

BACKGROUND: This study compared the long-term effects of switching from cyclosporine to tacrolimus on the incidence, progression, and severity of chronic renal allograft failure in patients with elevated serum creatinine levels. METHODS: Patients were assigned randomly (2:1) to switch to tacrolimus or remain on cyclosporine. Tacrolimus was initiated at 1/50th of the cyclosporine dose or 0.15 mg/kg/day, whichever dose was lower, to maintain trough concentrations between 5 and 15 ng/mL. Cyclosporine doses were adjusted to achieve trough concentrations between 100 and 300 ng/mL. RESULTS: At 60 months, the median change from baseline in serum creatinine was -0.2 mg/dL in the tacrolimus group and 0.3 mg/dL in the cyclosporine group (P=0.003). Median change in estimated creatinine clearance was 1.2 mL/min in the tacrolimus group and -4.1 mL/min in the cyclosporine group (P=0.019). The incidence of new-onset diabetes, hyperglycemia, hypertension, lymphoma, and malignancies was generally low and comparable between groups. Fewer patients in the tacrolimus group than in the cyclosporine group developed new cardiac conditions (11% vs. 28%, P=0.004), had low-density lipoprotein (LDL) cholesterol values more than 130 mg/dL (29% vs. 57%, P=0.002), or developed hyperlipidemia (24% vs. 67%, P=0.046) during the 60-month follow-up period. Despite these changes, patient and graft survival were similar for both groups. CONCLUSION: Switching from cyclosporine to tacrolimus resulted in improved renal function and a reduction in the occurrence of new-onset cardiac conditions and hyperlipidemia, with no increase in the incidence of new-onset diabetes or new-onset hyperglycemia. However, after 5 years there was no impact on patient or graft survival.

Effect of cyclosporine and sirolimus on the expression of connective tissue growth factor in rat experimental chronic nephrotoxicity.

BACKGROUND/AIMS: Connective tissue growth factor (CTGF) is a pro-fibrotic growth factor that acts downstream of transforming growth factor (TGF)-beta. However, CTGF regulation remains unknown. We tried to determine the effect of two commonly used immunosuppressants, cyclosporine (CsA) and sirolimus (SRL), on CTGF expression in a model of chronic nephrotoxicity. METHODS: Adult Sprague-Dawley rats kept on a low-salt diet were treated daily for 4 weeks with vehicle (VH), SRL (0.3 mg/kg), CsA5 (5 mg/kg), CsA10 (10 mg/kg) or both CsA5 and SRL. CTGF and TGF-beta1 expressions were evaluated by Northern blot. Functional and histologic parameters in addition to number of apoptotic cells were determined. RESULTS: At 28 days, both CsA doses were capable of inhibiting CTGF mRNA expression to levels similar to control. On the other hand, SRL increased CTGF expression by 3.5-fold. However, addition of CsA to SRL completely reversed that trend and returned levels to control. The results were different for TGF-beta1, which was increased by both CsA and SRL and to a greater extent by the drug combination. CONCLUSION: Unlike TGF-beta, CTGF does not seem to play an important role in CsA-induced chronic nephrotoxicity. In addition, calcineurin-dependent pathways are likely involved in CTGF regulation.

The association between length of post-kidney transplant hospitalization and long-term graft and recipient survival.

BACKGROUND: There has been a general trend towards shortened length of post-kidney transplant hospitalization (LOH). The decision regarding patients's discharge from the hospital theoretically may be based on several factors, including, but not limited to, patient well being, insurance status, family situation and other, mostly socio-economic factors, as opposed to hard medical evidence. However, the appropriate LOH in kidney transplant recipients is not well studied regarding long-term outcomes. METHODS: This study retrospectively analysed the association between LOH and graft and recipient survival based on United States Renal Data System dataset. In total, 100,762 patients who underwent transplant during 1995-2002 were included. Kaplan-Meier survival analysis and Cox models were applied to the whole patient cohort and on sub-groups stratified by the presence of delayed graft function, patient comorbidity index and donor type (deceased or living). RESULTS: In recipient survival, both short (<4 d) and long (>5 d) LOH showed a significant adverse effect (p < 0.01) on survival times. In the analysis of graft survival, long LOH (>or=2 wk) also showed significant adverse effects (p < 0.001) on survival times. However, short LOH (<4 d) did not reach statistical significance, although it was still associated with adverse effects on graft survival. These observations were consistent across the whole patient cohort and sub-groups stratified by the presence of delayed graft function, patient comorbidity index and donor type. CONCLUSION: Clinical considerations should be used to make the decision regarding appropriate time of post-kidney transplant recipient discharge. Based on this study, shorter than four d post-kidney transplant hospitalization may potentially be harmful to long-term graft and recipient survival.

Role of maintenance immunosuppressive regimen in kidney transplant outcome.

Data of long-term immunosuppressive protocol comparison are lacking. The goal of this study was to compare kidney transplant outcome using three common immunosuppressive protocols. A retrospective study was performed of the graft and recipient survival using US Renal Data System data (n = 31,012) between January 1, 1995, and December 31, 1999, with the follow-up through December 31, 2000, on prednisone + cyclosporine + mycophenolate mofetil (PCM; n = 17,108), prednisone + tacrolimus + mycophenolate mofetil (PTM; n = 7225), or prednisone + cyclosporine + azathioprine (PCA; n = 6679). Compared with PCM, there is an increased risk for allograft failure associated with PTM (hazard ratio [HR] 1.09; P < 0.05) and PCA (HR 1.15; P < 0.001). Similar associations were demonstrated in the following subgroups: Early (before 1997) and late (in or after 1997) transplant periods, in living-donor transplants, and in adult and kidney-only recipients. This association also was found between PCA regimen and graft survival in the entire patient population (HR 1.15; P < 0.001) and in the studied subgroups. PCA (HR 1.15; P < 0.005), but not PTM (HR 1.01; P = 0.816), regimen was associated with increased recipient mortality in the entire patient population and in patient subgroups. Secondary outcomes (serum creatinine values at given time points, acute rejection rate, and posttransplantation malignancies) are also discussed. These data suggest that a PCM regimen is associated with lower risk for graft failure compared with a PTM regimen and with lower risk for graft failure and recipient death compared with a PCA regimen.

A retrospective assessment of pre-treatment variables on the response to darbepoetin alfa after renal transplantation.

This retrospective review assesses the efficacy of darbepoetin alfa for treating anemia after renal transplantation. Patients were evaluated over a 12-week period, and efficacy was based on achieving hemoglobin >12 g/dL. Thirty-six patients were analyzed (53% male, 53% cadaveric allografts, median age 42.5 years). Baseline creatinine clearance ranged from approximately 15 to >100 mL/min. Most patients initiated darbepoetin alfa <3 months (50%) or >12 months (44%) after transplantation, 19% were previously receiving recombinant human erythropoietin (rHuEPO), and 47% were on concomitant ACE inhibitors. The majority of patients received either tacrolimus- (53%) or cyclosporine- (44%) based immunosuppression. Overall, 29 (81%) patients achieved the hemoglobin target with a mean time to response of 4.4 weeks. Neither the time to anemia onset, previous rHuEPO therapy, concomitant ACE inhibitor, allograft source, immunosuppressive regimen, nor degree of renal function affected the proportion of patients achieving the hemoglobin target, time to response or darbepoetin alfa dose requirement. Patients with anemia >12 months post-transplantation or on concomitant ACE inhibitors required a significantly longer duration of therapy. No adverse events associated with darbepoetin alfa therapy were detected. These results demonstrate that darbepoetin alfa is a safe and effective treatment for anemia in renal transplant recipients.

Effect of pirfenidone on apoptosis-regulatory genes in chronic cyclosporine nephrotoxicity.

BACKGROUND: : Apoptosis was shown to play a role in the progression of fibrosis in a chronic cyclosporine A (CsA) nephrotoxicity animal model. In addition, the antifibrotic molecule pirfenidone (PFD) was shown to ameliorate fibrosis in this model. We evaluated the role of PFD on the expression of apoptosis-regulatory genes in the kidneys of CsA-treated rats. METHODS: : Rats were administered CsA 7.5 mg/kg per day, CsA+PFD (250 mg/kg/day), vehicle (VH), or VH+PFD, and sacrificed at 28 days. Physiologic and histologic changes were studied, and apoptosis was detected by terminal deoxynucleotide transferase-mediated dUTP nick-end labeling stain. The mRNA expression of pro-apoptotic genes p53 and Fas-ligand was evaluated by quantitative polymerase chain reaction, and that of Bcl-xL, an anti-apoptotic gene, was evaluated by Northern blot analysis. In addition to mRNA expression, immunohistochemical studies of caspase 3 were performed. RESULT: : PFD administration to CsA-treated rats significantly ameliorated nephrotoxicity. Apoptosis-positive cells were increased by CsA but significantly reduced by PFD treatment (68+/-19 vs. 3+/-1, P<0.01). In addition, PFD down-regulated the mRNA expression of CsA-induced p53 and Fas-ligand (P<0.01) and increased that of Bcl-xL, previously reduced by CsA (P<0.01). Finally, PFD significantly down-regulated caspase 3 expression, present mostly on renal tubular epithelial cells. None of these changes were observed in VH-treated rats. CONCLUSION: : Whereas CsA favored the expression of pro-apoptotic genes, that effect was ameliorated by PFD. Because apoptosis can partly explain the loss of cells associated with fibrosis, the influence of PFD on apoptosis-regulatory genes in a manner that reduces apoptosis may explain some of its antifibrotic properties.