Effect of corticosteroid withdrawal on tacrolimus and mycophenolate mofetil exposure in a randomized multicenter study

As corticosteroid-sparing protocols are increasingly utilized in kidney transplant recipients, it is crucial to understand potential drug interactions between tacrolimus (TAC) and the effect of corticosteroid withdrawal as well as to characterize dose adjustments of mycophenolate mofetil (MMF) in this setting. This prospective, multicenter, randomized, double-blind study included 397 patients who were randomized on posttransplant day 8 to receive either placebo (CSWD) or corticosteroid continuance (CCS). TAC trough levels at week two posttransplant were significantly greater in the CSWD group whereas TAC doses were comparable to the CCS group. This interaction was not observed in the African American subgroup. Higher serum creatinine and potassium levels were also observed in the CSWD group. MMF dose was significantly reduced in the CSWD group by the investigators because of decreased WBC counts, mostly outside of study protocol criteria, despite similar incidence of neutropenia and reported cytomegalovirus infection. Understanding TAC and MMF exposure in the context of corticosteroid-sparing protocols should allow for improved dosing of immunosuppressants and better management of posttransplant patients.

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.

Cytomegalovirus incidence between everolimus versus mycophenolate in de novo renal transplants: pooled analysis of three clinical trials

Everolimus (EVR) in heart and renal transplant (RTx) recipients may be associated with a decreased incidence of cytomegalovirus (CMV). A detailed analysis of the association between EVR versus mycophenolic acid (MPA) and CMV events has not been reported. CMV data from 2004 de novo RTx recipients from three-randomized, prospective, EVR studies A2309 (N = 833), B201 (N = 588) and B251 (N = 583) were retrospectively analyzed to identify differences between two EVR dosing groups and MPA. EVR groups received 1.5 mg/day, or 3 mg/day with either standard (SD-CsA) or reduced dose cyclosporine (RD-CsA). Controls received MPA with SD-CsA. CMV prophylaxis was as per center practice. CMV incidence (infection/syndrome, disease, viremia) was captured per local center evaluations. Kaplan-Meier analyses demonstrated that freedom from CMV viremia and infection/syndrome was significantly greater for EVR versus MPA for recipients without CMV prophylaxis. Among recipients who received prophylaxis, freedom from viremia was greater for EVR 3.0 mg; freedom from infection/syndrome was greater for EVR 3.0 and 1.5 mg. Although freedom from organ involvement was numerically greater for EVR, it was not statistically significant. This analysis documents significant reductions in the incidence of CMV infection/syndrome and viremia in EVR-treated de novo RTx recipients, especially those who did not receive CMV prophylaxis versus MPA.

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.

Preconditioning: from experimental findings to novel therapies in acute kidney injury

Improving the ability of the kidney to tolerate injury through preconditioning is likely to have important clinical implications. Although a number of preconditioning strategies have been studied, ischemic preconditioning (IP) has been studied the most experimentally. The information gathered has helped us shed more light into the mechanisms responsible for this tissue adaptation that confers to tissues a more resistant status. IP is effective within minutes, suggesting that preformed mediators are involved. This is followed by delayed preconditioning, a phenomenon that is less potent but longer acting. Remote preconditioning occurs also in non-affected tissues and can be transferable. A number of mediators and transcription factors have been implicated including kinases, heat shock proteins, nitric oxide and neurogenic pathways, all of which help change the cell into a more resistant phenotype. There is evidence that IP also occurs in the human environment with lessons learned from myocardial ischemia, hepatic resection and cerebral ischemia. Because of the ethical impediment with intentionally applying organ ischemia, there has been an interest in pharmacological preconditioning lately. Exogenously administered erythropoietin was shown to benefit kidneys subjected to different insults. In addition, mesenchymal stem cells-based approaches for the prevention and treatment of acute kidney injury (AKI) are being studied. Calcineurin inhibitors may represent a viable way to reduce ischemia reperfusion injury in transplantation. Translating the experimental findings to the clinical arena remains a challenge. The discovery of new biomarkers for AKI should help initiate therapy early, when therapy could make a difference.

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.

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.

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.

Lipid-based amphotericin in pulmonary zygomycosis: safety and efficacy of high exposure in a renal allograft recipient

Zygomycosis is associated with a high mortality in immunosuppressed patients. Treatment typically includes surgical resection and administration of intravenous amphotericin B. Success of treatment may require withdrawal of immunosuppression, with risk of graft loss. We report the successful treatment of invasive pulmonary zygomycosis, following initial surgical resection, using very high doses of lipid-based amphotericin B without withdrawal of immunosuppression. The patient received daily doses up to 10 mg/kg/day (51 g cumulatively) of lipid-based amphotericin B along with a brief course of intrapleural amphotericin. Despite immunosuppression not being withdrawn, the patient's kidney allograft function remained stable. We conclude that high doses of lipid-based amphotericin B can be safe and effective as part of the treatment regimen for pulmonary zygomycosis.

Sirolimus increases transforming growth factor-beta1 expression and potentiates chronic cyclosporine nephrotoxicity

BACKGROUND

Sirolimus (SRL) is increasingly being used to decrease cyclosporine (CsA) exposure. SRL is not known to be nephrotoxic and has a mechanism of action distinct from CsA. We investigated the effect of combining CsA and SRL on renal structure and function and on transforming growth factor-beta1 (TGF-beta1) and extracellular matrix (ECM) proteins in a model of chronic CsA nephrotoxicity.

METHODS

Rats treated with vehicle, SRL 0.3 mg/kg/day, CsA 5 or 10 mg/kg/day, or CsA5+SRL were sacrificed at 7 or 28 days. Physiologic and histologic changes were studied in addition to TGF-beta1 mRNA and protein expressions, and mRNA expression of plasminogen activator inhibitor-1 (PAI-1) and ECM proteins biglycan and types I and IV collagen.

RESULTS

While SRL alone did not alter renal function and structure, it potentiated the nephrotoxic actions of CsA when used in combination with low-dose CsA5 and resulted in significant changes similar to high-dose CsA10. In addition, SRL alone increased TGF-beta1 by 44% to 49% (P < 0.05 vs. VH). When used in combination with low-dose CsA5, SRL potentiated TGF-beta1 mRNA and protein by 121% and 176%, respectively (P < 0.05 vs. VH and CsA5), to levels achieved with high-dose CsA10. The expression of the ECM proteins followed that of TGF-beta1; a similar effect was observed with PAI-1, suggesting a decrease in ECM degradation.

CONCLUSION

Because SRL augments nephrotoxicity, caution should be exercised when it is used in combination with CsA. More studies are needed to determine the long-term clinical impact of SRL on nephrotoxicity and allograft function.

Combination therapy with sirolimus and mycophenolate mofetil: effects on the kidney and on transforming growth factor-beta1

Sirolimus (SRL) is not nephrotoxic, but it has been shown to increase transforming growth factor (TGF)-beta. We investigated the effect of combining mycophenolate mofetil (MMF) with SRL on renal structure and function and on TGF-beta1. Rats treated with vehicle (VH), MMF 10 mg/kg/d, SRL 0.3 mg/kg/d, or SRL+MMF were killed at 28 days. The physiologic and histologic changes and expression of TGF-beta1, plasminogen activator inhibitor-1, and extracellular matrix proteins were studied. Although SRL alone did not alter renal function and structure, it increased TGF-beta1 mRNA by 44% and protein by 48% (P <0.05 vs. VH). Treatment with MMF did not affect TGF-beta1. When combined with SRL, MMF decreased TGF-beta1 expression to VH levels. A similar trend was observed with plasminogen activator inhibitor-1 and extracellular matrix proteins. The long-term consequence of increased TGF-beta in SRL-treated kidneys remains unknown. However, because MMF can reverse this trend, SRL and MMF combination therapy may be protective.

Mycophenolate mofetil ameliorates arteriolopathy and decreases transforming growth factor-beta1 in chronic cyclosporine nephrotoxicity

Afferent arteriolopathy is the most characteristic lesion of chronic cyclosporine (CsA) nephrotoxicity. We investigated the effect of therapeutic doses of mycophenolate mofetil (MMF) in a model of chronic CsA nephrotoxicity where transforming growth factor-beta (TGF-beta) was shown to play a central role. Rats treated with vehicle, MMF 10 mg/kg/day, CsA 10 mg/kg/day or CsA + MMF were sacrificed at 7 or 28 days. Physiologic and histologic changes were studied in addition to TGF-beta1 mRNA and protein expressions, and mRNA expression of plasminogen activator inhibitor-1 (PAI-1) and the extracellular matrix (ECM) proteins biglycan and types I and IV collagen. While MMF markedly ameliorated afferent arteriolopathy, it had no significant effect on interstitial fibrosis and tubular atrophy. In addition, MMF treatment reduced both TGF-beta1 mRNA and protein levels by 39% and 32%, respectively (p < 0.05 vs. CsA only). The expression of the ECM proteins followed that of TGF-beta1 and was significantly decreased with MMF; a similar effect was observed with PAI-1, suggesting an increase in ECM degradation. These results suggest that MMF exerts a beneficial effect on CsA arteriolopathy and that it decreases TGF-beta1. While this drug combination may be useful clinically, long-term studies are needed to determine if MMF has a lasting benefit.

Lack of economic benefit with basiliximab induction in living related donor adult renal transplant recipients

STUDY OBJECTIVE

To assess the effect of basiliximab (BAS) induction therapy on acute rejection rates and overall costs in adult living related donor (LRD) renal transplant recipients. Design. Retrospective chart review and cost-effectiveness analysis of the first 12 months after transplantation.

SETTING

University hospital and outpatient renal transplant clinic.

PATIENTS

Sixty consecutive adult LRD renal transplant recipients.

INTERVENTION

The treatment group received BAS 20 mg intravenously on postoperative days 0 and 4. The control group received no induction agents. Both groups received cyclosporine microemulsion, azathioprine, and corticosteroids for maintenance immunosuppression.

MEASUREMENTS AND MAIN RESULTS

Six patients (three in each group) were excluded; three had received muromonab-CD3 as an induction agent and three were lost to follow-up. At 12-months, the frequency of acute rejection episodes was 15% (4/27) in the control group and 22% (6/27) in the BAS group (NS). Renal function, as measured by average serum creatinine level, was similar at months 1, 2, 3, 6, and 12 for both groups. The frequency of infectious complications was similar in both groups. No adverse effects were associated with BAS. Mean initial hospitalization charges were dollar 51,970.01 and dollar 68,093.90 in the control and BAS groups, respectively (p < 0.05). The control group had more readmissions (18 vs 14 in the BAS group), but the average charge/readmission was lower (dollar 10,148.50 vs dollar 21,952.58 in the BAS group; NS). All costs were adjusted to 2000 dollars (US).

CONCLUSION

Basiliximab induction therapy did not provide clear clinical efficacy benefit or prove to be cost-effective compared with no induction in LRD recipients.

Nitric oxide modulates vascular endothelial growth factor and receptors in chronic cyclosporine nephrotoxicity

BACKGROUND

Vascular endothelial growth factor (VEGF) is involved in angiogenesis, wound healing, and inflammation and exerts its effect via tyrosine kinase receptors, fms-like tyrosine kinase (Flt-1) and fetal liver kinase (Flk-1 or KDR). We have previously shown that VEGF is up-regulated in a model of chronic cyclosporine (CsA) nephrotoxicity and that l-arginine (l-Arg) improved while N-nitro-l-arginine-methyl ester (L-NAME) worsened fibrosis. We examined the role of nitric oxide modulation on VEGF in this model.

METHODS

Pair-fed salt-depleted rats were administered CsA, CsA + L-NAME, CsA +l-Arg, vehicle (VH), VH + L-NAME or VH +l-Arg and were sacrificed at 7 or 28 days. Physiologic and histologic changes were studied in addition to the mRNA expression of VEGF and its receptors Flt-1 and KDR/Flk-1 by Northern blot and the protein expression of VEGF by Western blot and immunohistochemical staining.

RESULTS

While L-NAME worsened renal function and histology, l-Arg had the opposite beneficial effect in CsA-treated rats. VEGF mRNA and protein expressions increased with CsA, further increased with L-NAME and became significantly reduced with L-Arg. Flt-1 expression was similar in all groups. On the other hand, KDR/Flk-1 mRNA expression was modulated in a fashion similar to VEGF. Also, nitric oxide modulation did not have an effect on VH-treated rats.

CONCLUSIONS

VEGF expression in chronic CsA nephrotoxicity is increased by nitric oxide blockade and decreased by nitric oxide enhancement. Moreover, VEGF probably exerted its effect via the KDR/Flk-1 receptor. The actions of VEGF in this model remain speculative, but it is probable that VEGF plays a role, either independently or through nitric oxide, in CsA-induced fibrosis.

Recurrent lupus nephritis in the second allograft of a patient with systemic lupus erythematosus

Lupus glomerulonephritis is a common and serious complication of systemic lupus erythematosus (SLE) affecting up to 50% of lupus patients. Recurrent lupus nephritis is rare, complicating as low as 1% of the lupus transplant population according to some authors. However, it may be underreported with more realistic recurrent rates oscillating from 2.8 to 8.7%. We report the case of a patient with SLE who lost her first allograft 4 years after transplantation with a diagnosis of de novo fibrillary glomerulopathy. She underwent a second renal transplantation and her renal function was stable for the past 5 years. She now presented with skin rash, arthralgias and positive lupus serologies. Her creatinine was slightly elevated and proteinuria was also noted. A renal biopsy performed revealed a recurrent focal proliferative lupus nephritis (WHO III). Retrospectively, we believe that her first allograft was also lost to recurrent lupus nephritis. This is a unique case of recurrent lupus nephritis in the second allograft of a patient with SLE.

De novo C1q nephropathy in the renal allograft of a kidney pancreas transplant recipient: BK virus-induced nephropathy?

C1q nephropathy is a distinct entity characterized by extensive and dominant C1q mesangial deposition with associated steroid resistant proteinuria in the absence of systemic lupus erythematosus. Several morphological patterns ranging from very subtle glomerular alterations to focal/segmental glomerulosclerosis and mesangial proliferative changes have been described. Interstitial nephritis secondary to BK polyomavirus is a recently recognized complication in kidney transplant recipients. It may be associated with a tubulitis-like picture, mimicking sometimes acute tubular rejection. We report the case of a kidney pancreas transplant recipient who developed de novo C1q nephropathy, in the setting of BK polyomaviral interstitial nephritis. He presented with renal allograft dysfunction and a kidney biopsy was performed. It was interpreted as acute cellular rejection. C1q deposits were detected by immunofluorescence studies and electron microscopy. The patient did not respond clinically to appropriate anti-rejection treatment and a second renal biopsy was performed. The possibility of an interstitial nephritis secondary to BK polyomavirus mimicking rejection was suggested. Special immunohistochemical and blood/urine PCR studies for BK virus were performed, confirming the diagnosis of BK virus tubulonterstitial nephritis with a persistent, probable BK virus induced C1q nephropathy.

Angiotensin II regulation of vascular endothelial growth factor and receptors Flt-1 and KDR/Flk-1 in cyclosporine nephrotoxicity

BACKGROUND

Vascular endothelial growth factor (VEGF) is involved in angiogenesis, wound healing and inflammation. VEGF exerts its effect via the tyrosine kinase receptors Flt-1 and KDR/Flk-1. We have previously shown that VEGF is up-regulated in a chronic cyclosporine (CsA) nephrotoxicity model. Our current study examined the role of angiotensin II (Ang II) blockade with enalapril (E) or losartan (L) on VEGF in this model.

METHODS

Pair-fed salt-depleted rats were administered vehicle, CsA, CsA + nilvadipine, CsA + hydralazine/hydrochlorthiazide (HCTZ), CsA + E or CsA + L, and were sacrificed at 7 or 28 days. Physiologic and histologic changes were studied in addition to the mRNA expression of VEGF and its receptors Flt-1 and KDR/Flk-1 by Northern blot, and the protein expression of VEGF by Western blot.

RESULTS

While all groups achieved similar blood pressures and creatinine clearances, the amelioration in nephrotoxicity was observed only with Ang II blockade. VEGF mRNA and protein expressions increased with CsA and became significantly reduced with Ang II blockade. Flt-1 expression was similar in all groups; it decreased early and remained low. On the other hand, KDR/Flk-1 mRNA expression was higher at seven days in all groups, except in the +E and +L groups where it was significantly lower, and then became further down-regulated at 28 days.

CONCLUSIONS

The increased VEGF expression in chronic CsA nephrotoxicity seems to be related to up-regulation of Ang II. In addition, VEGF probably exerted its effect via the KDR/Flk-1 receptor. The actions of VEGF in this model remain speculative, but may be related to its effect on macrophage infiltration or matrix deposition.

Pirfenidone treatment decreases transforming growth factor-beta1 and matrix proteins and ameliorates fibrosis in chronic cyclosporine nephrotoxicity

Chronic cyclosporine (CsA) nephrotoxicity is characterized by tubulointerstitial fibrosis. Pirfenidone (PFD) is a novel antifibrotic compound that was shown to prevent and even reverse fibrosis. The mechanism of action of PFD is unclear but involves inhibition of transforming growth factor-beta (TGF-beta). Salt-depleted rats were administered CsA, CsA + PFD, vehicle (VH) or VH + PFD and sacrificed at 28days. Physiologic and histologic changes were studied in addition to TGF-beta1, plasminogen activator inhibitor-1 (PAI-1) and biglycan mRNA expressions by Northern blot. TGF-beta1 immunohistochemistry was also performed. Treatment with PFD ameliorated CsA-induced fibrosis by about 50% (p < 0.05). CsA-induced decrease in creatinine clearance improved with PFD but the difference was not significant. TGF-beta1, PAI-1 and biglycan mRNA expressions increased with CsA (p < 0.05 vs. VH) but strikingly improved with PFD treatment (p < 0.05 vs. CsA), which brought the levels down to VH levels. PFD treatment also decreased TGF-beta1 protein expression by 80%. These results demonstrate that PFD can attenuate renal fibrosis in this model. PFD was associated with a decrease in TGF-beta1 expression, which, in turn, was associated with a decrease in matrix deposition. These experiments suggest that PFD can be clinically useful for preventing chronic CsA nephrotoxicity and may prove to be helpful in other progressive renal diseases.

Expression of vascular endothelial growth factor and its receptors Flt-1 and KDR/Flk-1 in chronic cyclosporine nephrotoxicity

BACKGROUND

Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen involved in angiogenesis, wound healing, and inflammation.

METHODS

Rats placed on low salt diet (LSD) or normal salt diet (NSD) were treated with cyclosporine (CsA) or vehicle (VH) and killed at 7 or 28 days. We studied the expression of VEGF and its receptors Flt-1 and KDR/Flk-1 mRNA by Northern and that of VEGF protein by Western blot.

RESULTS

CsA induced VEGF mRNA and protein expressions at 7 and 28 days in LSD rats. At 7 days, CsA up-regulated the expression of Flt-1 and KDR/Flk-1 receptors; however, at 28 days, Flt-1 remained unchanged whereas KDR/Flk-1 expression declined. In NSD rats, in which the lesion did not develop, the expression of VEGF and its receptors remained similar to control.

CONCLUSIONS

What causes VEGF to be up-regulated remains unclear. Further studies are needed to study the role of hypoxia and other cytokines in relation to VEGF in this model.

De novo fibrillary glomerulopathy in the renal allograft of a patient with systemic lupus erythematosus

Lupus glomerulonephritis is a complication of systemic lupus erythematosus, with 10% of the patients developing end-stage renal disease. It is accepted that lupus patients are good candidates for kidney transplantation and that the disease activity is subdued after transplantation due to rigorous immunosuppression, with a low rate of graft loss due to recurrent glomerulonephritis. While recurrent fibrillary glomerulopathy has been reported in renal allografts, de novo disease has not. We report a patient with systemic lupus who underwent a renal transplantation and subsequently lost her allograft due to de novo fibrillary glomerulopathy. Four years after her first kidney transplant, the patient presented with acute deterioration of her renal function. A renal biopsy was performed, and it revealed a focal mesangioproliferative pattern with positive amorphous mesangial immunofluorescence staining for IgG and C3. Congo red staining was negative. Electron microscopy demonstrated the presence of randomly oriented nonamyloid fibrils in the mesangiun. The diagnosis of de novo fibrillary glomerulopathy was made. The patient lost her allograft and received a second cadaveric renal transplant 1 year later. She has had a stable renal function since then.

Effect of nitric oxide modulation on TGF-beta1 and matrix proteins in chronic cyclosporine nephrotoxicity

BACKGROUND

Chronic cyclosporine (CsA) nephrotoxicity is characterized by interstitial fibrosis and afferent arteriolar hyalinosis. L-arginine (L-Arg), the substrate for nitric oxide (NO) synthase and N-nitro-L-arginine-methyl ester (L-NAME), the NO synthase inhibitor, were shown to modulate acute CsA nephrotoxicity. However, the mechanism of fibrosis in chronic CsA nephrotoxicity remains unclear. Thus, we examined the effect of NO modulation on fibrosis and the expression of transforming growth factor-beta1 (TGF-beta1) and matrix proteins in chronic CsA nephrotoxicity.

METHODS

Rats were administered CsA (7.5 mg/kg), CsA + L-Arg (1.7 g/kg), CsA + L-NAME (3.5 mg/kg), vehicle (VH), VH + L-Arg, and VH + L-NAME, and were sacrificed at 7 or 28 days. NO production, physiologic parameters, and histology were studied in addition to the mRNA expression of TGF-beta1, plasminogen activator inhibitor-1 (PAI-1) and the matrix proteins biglycan and collagens type I and IV by Northern and the protein expression of PAI-1 and fibronectin by enzyme-linked immunosorbent assay.

RESULTS

While L-NAME strikingly reduced NO biosynthesis and worsened the glomerular filtration rate and CsA-induced fibrosis, L-Arg had the opposite beneficial effect. In addition, the CsA-induced up-regulated expression of TGF-beta1, PAI-1, and the matrix proteins biglycan, fibronectin, and collagen I was significantly increased with L-NAME and strikingly improved with L-Arg. Collagen IV expression was not affected. Also, NO modulation did not affect VH-treated rats.

CONCLUSIONS

Chronic CsA nephrotoxicity can be aggravated by NO blockade and ameliorated by NO enhancement, suggesting that NO maintains a protective function. NO modulation was associated with a change in TGF-beta1 expression, which, in turn, was associated with alterations in matrix deposition and matrix degradation through its effect on PAI-1.

Expression of apoptosis regulatory genes in chronic cyclosporine nephrotoxicity favors apoptosis

Expression of apoptosis regulatory genes in chronic cyclosporine nephrotoxicity favors apoptosis.

BACKGROUND

Chronic cyclosporine (CsA) nephrotoxicity is characterized by interstitial fibrosis, tubular dropout, and loss of cellularity in areas of fibrosis. Apoptosis was found to play a role in CsA-induced fibrosis. We evaluated the role of the death genes p53, Bax, and Fas-L (ligand), survival gene Bcl-2, interleukin-converting enzyme (ICE), and caspase-3.

METHODS

Salt-depleted rats were administered CsA 15 mg/kg/day or vehicle (VH) and were sacrificed at 7 or 28 days. Apoptosis was detected by TdT-mediated dUTP-biotin nick end labeling assay. p53 and Bax expressions were evaluated by Northern and Western blot analysis. Fas-L and Bcl-2 expressions were evaluated by immunofluorescence. In addition to ICE mRNA, caspase-3 enzymatic activity was assayed.

RESULTS

Although no differences were seen at one week, apoptosis-positive cells increased with CsA at four weeks (P < 0.05) and correlated with tubular atrophy and interstitial fibrosis (r = 0.8, P < 0.05). CsA induced the expression of p53 (P < 0.05) and Bax (P < 0.01) and decreased that of Bcl-2 (P < 0.05). CsA up-regulated Fas-L expression (P < 0.001). ICE mRNA and caspase-3 activity were also increased (P < 0.01). The changes occurred as early as one week and remained statistically significant at four weeks.

CONCLUSIONS

Specific apoptotic genes are increased in chronic CsA nephrotoxicity. The balance favors the induction of apoptosis. Increased apoptosis could explain the tubular dropout and loss of cellularity with fibrosis. This then may impair the ability of the tubulointerstitium to remodel. Apoptosis could also contribute to some of CsA immunosuppressive effects on activated lymphocytes.

Mechanism of fibrosis in experimental tacrolimus nephrotoxicity

The clinical use of tacrolimus (FK506) is limited by nephrotoxicity. The pathogenesis of fibrosis in chronic FK506 nephrotoxicity remains unknown. Because transforming growth factor (TGF)-beta plays a key role in the fibrogenesis of many diseases, including cyclosporine nephrotoxicity, we studied a salt-depleted rat model of chronic FK506 nephropathy in which clinically relevant FK506 blood levels are obtained and which shows similarities to the lesions described in patients receiving FK506. Pair-fed rats were treated with either FK506 (1 mg/kg/day s.c.) or an equivalent dose of vehicle and were killed at 7 or 28 days. Characteristic histologic changes of tubular injury, interstitial fibrosis, and arteriolopathy developed in FK506-treated rats at 28 days and were accompanied by worsening kidney function, decreased concentrating ability, and enzymuria. FK506-treated kidneys had a progressive increase in the expression of TGF-beta1 and matrix proteins (biglycan, tenascin, fibronectin, and type I collagen). This effect seems to be specific because the expression of type IV collagen, a basement membrane collagen, was not affected. Matrix deposition was present mostly in the tubulointerstitium and vessels in accordance with the FK506 chronic lesion. The expression of plasminogen activator inhibitor-1, a protease inhibitor influenced by TGF-beta, followed TGF-beta1 and matrix proteins, suggesting that the fibrosis of chronic FK506 nephropathy likely involves the dual action of TGF-beta1 on matrix deposition and degradation. Since both peripheral and tissue renin expression were elevated with FK506, the renin-angiotensin system may play a role in the pathogenesis of this condition.

Angiotensin II blockade decreases TGF-beta1 and matrix proteins in cyclosporine nephropathy

Angiotensin II (Ang II) is implicated in fibrosis but the precise mechanism of this effect remains unclear. In a model of chronic cyclosporine (CsA) nephropathy, we previously showed that TGF-beta1 plays a role in CsA-induced tubulointerstitial fibrosis and arteriolopathy by stimulating extracellular matrix (ECM) protein synthesis and inhibiting ECM degradation through increasing the synthesis of plasminogen activator inhibitor (PAI)-1. We hypothesized that Ang II contributes to fibrosis by inducing TGF-beta1. Salt-depleted rats were given placebo, CsA alone, CsA + nilvadipine, CsA + hydralazine/hydrochlorthiazide, CsA + losartan (AT1 receptor antagonist) or CsA + enalapril (Ang converting enzyme inhibitor) and were sacrificed at 7 and 28 days. All treated groups achieved similar blood pressures and glomerular filtration rates. The lesion of chronic CsA nephropathy was ameliorated by concomitant therapy with losartan or enalapril at 28 days, a phenomenon not observed in the other treatment groups. Similarly, Ang II blockade resulted in decreased expression of TGF-beta1 and PAI-1 by Northern and ELISA. Similarly, the expression of ECM proteins directly influenced by TGF-beta decreased with Ang II blockade. These results suggest that CsA-induced fibrosis in this model is independent of renal hemodynamics and is mediated, at least partly, through Ang II induction of TGF-beta1 expression.

Sodium depletion enhances fibrosis and the expression of TGF-beta1 and matrix proteins in experimental chronic cyclosporine nephropathy

The major limitation to the clinical use of cyclosporine (CsA) is renal toxicity. In the past, the lack of an animal model of chronic CsA nephropathy has hampered the study of its pathogenesis. Rats given CsA and placed on a low sodium diet (LSD) develop a histology similar to human lesions of chronic CsA nephropathy, a phenomenon not observed in animals on a normal sodium diet (NSD). We have previously shown that transforming growth factor-beta1 (TGF-beta1) is involved in the CsA-induced renal fibrosis in rats on a LSD. We hypothesized that sodium depletion is critical to the increase in TGF-beta1 expression, which, in turn, results in excessive matrix accumulation. Pair-fed rats were placed on a NSD or LSD, treated with CsA or vehicle, and killed at 7 or 28 days (N = 4 to 6 in each group). All rats achieved similar blood pressure control, and all CsA-treated rats achieved similar CsA blood levels. However, while CsA did not affect creatinine clearance in rats on a NSD, it lowered creatinine clearance in rats on a LSD (P < 0.01). Cyclosporine-induced tubulointerstitial fibrosis and arteriolopathy was observed at 28 days only in the rats on a LSD (P < 0.05). In addition, peripheral renin activity was increased only in the rats on a LSD (P < 0.01), while it remained normal in the rats on a NSD. In addition, CsA-treated rats on a LSD developed a progressive increase in the mRNA expression of TGF-beta1 and the matrix proteins biglycan and type I collagen at 7 and 28 days. Most of the changes were seen at 28 days (P < 0.001 for TGF-beta1, P < 0.01 for biglycan and type I collagen). On the other hand, CsA treatment in rats on a NSD did not affect the mRNA expression of TGF-beta1 and matrix proteins. Most of the changes in the immunofluorescence deposition of the glycoproteins tenascin and fibronectin EDA+ were in the tubulointerstitium and vessels of the kidneys of rats on a LSD and were mostly significant at 28 days, in accordance with the characteristic histology of chronic CsA nephropathy. The mRNA expression of plasminogen activator inhibitor-1, a protease inhibitor involved in matrix degradation and stimulated by TGF-beta1, was observed only in kidneys of rats on a LSD (P < 0.01). Since sodium depletion elevates peripheral renin activity, our experiments suggest a role for the renin-angiotensin system in the expression of TGF-beta1 and matrix proteins in CsA-induced renal fibrosis of rats on a LSD.

Identification of promoter activity and differential expression of transcripts encoding the murine stromelysin-1 gene in renal cells

Stromelysin-1, matrix metalloproteinase-3 (MMP-3), is an important endopeptidase selectively expressed by somatic cells in organ tissues. The renal tubulointerstitium, for example, comprises tubular epithelium and interstitial fibroblasts forming the principal mass of the kidney. We observed that mRNA encoding stromelysin-1 is detectable in murine renal fibroblasts, but not in proximal tubular epithelium. Transcripts measured by RNase protection assay in renal fibroblasts increase following exposure to phorbol ester, and thereafter, activated stromelysin-1 protein can be detected in culture media by Western blotting. A 6.4 Kb genomic clone containing the putative stromelysin-1 promoter was isolated and a relevant 2.1 Kb PstI restriction fragment including 2.1 Kb of the immediate 5'-flanking region was sequenced on both strands. Two transcriptional start sites were identified by primer extension; the major start site corresponded to a previously established position in the rat promoter, and a second undescribed minor transcriptional start site was located 16 bp upstream of the primary site. A HiNF-A chromatin-activating element at -106 bp was found in the early promoter region of pR336 and an active AP-1 site at -72 bp with an Ets/PEA-3 motif at -203 bp was suggested by transient transfection of luciferase minigenes into renal fibroblasts responsive to phorbol ester. This Ets element was identical to a site in the early promoter of the fibroblast-specific gene FSP1. A baseline enhancement in activity of pR336 in fibroblasts was further observed with the addition of 5' flanking sequence out to -1980 bp. This additional region of flanking sequence contains two modular regions: one of multiple PEA-3 elements between -684 bp and -1955 bp and a second region between -1929 bp and -1980 bps containing a second AP-1 site at -1929 bp, a MBF-1/ MEP-1 metal binding site, and a PPAR peroxisome proliferator element at -1950 bp. Our findings implicate a gene structure with expected activity in a mesenchymal phenotype. The PKC-dependent regulation of the stromelysin-1 gene supports the notion that it may be modulated during inflammation or tissue remodeling.

Expression of TGF-beta 1 and matrix proteins is elevated in rats with chronic rejection

The pathogenesis of fibrosis in chronic renal allograft rejection remains unknown. Since TGF-beta 1 plays a key role in fibrogenesis, we studied a rat model of chronic allograft rejection that shows similarities to the structural lesion described in patients. We previously demonstrated an increased expression of TGF-beta 1 in human kidney biopsies with acute and chronic rejection. Recipients of renal allografts (F344-Lewis) and isografts (Lewis-Lewis) were sacrificed at 4, 8, 24 and 52 weeks. Characteristic histologic changes of chronic rejection developed in the allografts as early as four weeks and were accompanied by progressive albuminuria significant by eight weeks. Allografts showed a progressive increase in mRNA expression of TGF-beta 1 and matrix proteins during the 52 week course. Increased matrix deposition by immunofluorescence was mostly present in the interstitium and vessels early and in all kidney compartments later. The mRNA expression of plasminogen activator inhibitor, a protease inhibitor stimulated by TGF-beta 1, increased along with TGF-beta 1 and matrix proteins. These results suggest that the fibrosis of chronic renal allograft rejection is mediated, at least partly, by the dual action of TGF-beta 1 on matrix deposition and degradation.

Cyclosporine nephropathy: pathophysiology and clinical impact

Cyclosporine (CsA) has markedly improved the results of transplantation, and its use has been extended to include autoimmune and primary renal diseases. However, the major limitation to its nephrotoxicity. Acutely, a reversible form of renal vasoconstriction can occur in all patients receiving CsA. In addition, progressive renal insufficiency owing to CsA has also been well documented. Clinically, long-term CsA nephrotoxicity is characterized by slowly progressive azotemia, proteinuria, and hypertension. Histologically, there is striped tubulointerstitial fibrosis, tubular atrophy, and afferent arteriolopathy. New evidence suggests that the histological changes in long-term CsA nephropathy are independent of the functional changes. Recently transforming growth factor (TGF)-beta was shown to be upregulated along with matrix proteins in a model of CsA nephrotoxicity. Because TGF-beta has immunosuppressive activities, it was suggested that it may contribute not only to CsA nephrotoxicity, but also to the mechanism of action of CsA. A number of strategies have been devised to try to minimize CsA nephrotoxicity, but remain inconclusive. Presently, it is not clear what role CsA therapy plays in the chronic failure of renal allografts. Continued research should give new insights into measures to overcome CsA-induced scarring in the kidney.

Role of transforming growth factor-beta 1 in experimental chronic cyclosporine nephropathy

The pathogenesis of fibrosis in chronic cyclosporine (CsA) nephropathy remains unknown. Since TGF-beta 1 plays a key role in the fibrogenesis of a number of renal diseases, we studied a salt-depleted rat model of chronic CsA nephropathy which shows similarity to the structural and functional lesions described in patients. Pair fed rats were treated with either CsA (15 mg/kg/day s.c.) or an equivalent dose of olive oil and sacrificed at 7 and 28 days. Characteristic histologic changes of proximal tubular injury, tubulointerstitial fibrosis and arteriolopathy developed in CsA-treated rats at day 28. They were accompanied by physiologic changes of increased serum creatinine, decreased creatinine clearance, increased enzymuria and decreased concentrating ability. CsA-treated rats showed a progressive increase in mRNA expression of TGF-beta 1 and matrix proteins at days 7 and 28. Most of the changes were in the tubulointerstitial and vascular compartments by immunofluorescence with a predominant involvement of the medulla as compared to cortex. The mRNA expression of plasminogen activator inhibitor, a protease inhibitor stimulated by TGF-beta 1, followed TGF-beta 1 and matrix proteins, suggesting that the fibrosis of chronic CsA nephropathy likely involves the dual action of TGF-beta on matrix deposition and degradation.

Hyperadrenergic state following acute withdrawal from clonidine used at supratherapeutic doses

Abrupt cessation of clonidine treatment precipitates a physiological withdrawal syndrome, thought to be due to a hyperactive state of central autonomic and cognitive adrenergic neuronal systems dependent on presynaptic alpha 2-adrenoceptors and/or imidazoline receptors. We hereby describe a 36-year-old male with history of end-stage renal disease, hypertension and medication non-compliance, who presented with severe hypertension and remarkable agitation. His daily clonidine intake was estimated to be 10 mg. The patient had abruptly discontinued his clonidine five days prior to admission. The following indices of adrenergic activity were measured in plasma (normal control values in parentheses): noradrenaline (NA) 8.59 nmol/l (1.32-4.56 nmol/l), adrenaline (Adr) 1.86 nmol/l (0.83-4.20) nmol/l), total 3-methoxy-4-hydroxyphenylglycol (MHPG) 152.8 nmol/l (45.1-111.5 nmol/l), and free MHPG 33.0 nmol/l (12.2-31.4 nmol/l). Plasma clonidine level was 3.53 ng/ml (15.9 nmol/l) with the usual therapeutic level being < 2.0 ng/ml (8.9 nmol/l). Initially, the patient received sedatives and was started on clonidine for the first 24 hours only, after which time period prazosin was started, with good response of his blood pressure and reversal of his mental status changes. At that point, the plasma values of indices of adrenergic activity had decreased compared with their corresponding initial values by the following percentages: NA 60.6%, Adr 22.6%, total MHPG 42.2% and free MHPG 11.5%. Plasma clonidine level had decreased now by 43.6% to an absolute value of 1.99 ng/ml (8.85 nmol/l). We emphasize that physicians should be aware of clonidine's abuse potential and caution should be taken, as well as the appropriate route chosen, when prescribing clonidine in patients who show features of poor compliance to medications and especially in patients with psychoses, suicide potential or personality disorders.

Transforming growth factor-beta and matrix protein expression in acute and chronic rejection of human renal allografts

Because the increased tissue expression of TGF-beta underlies fibrosis in many diseases, it was hypothesized that sustained elevated transforming growth factor (TGF)-beta overexpression might be responsible for fibrosis in chronic rejection of the renal allograft. To test this hypothesis, biopsies were obtained from 5 patients with acute rejection, 5 patients with chronic rejection, 10 normal individuals, and 10 patients with kidney disease. The tissues were examined by immunofluorescence for the three TGF-beta isoforms (1, 2, and 3) and the two matrix proteins induced by TGF-beta that serve as markers of fibrosis: fibronectin extradomain A positive (EDA+) and plasminogen activator inhibitor-1 (PAI-1). The tubulointerstitium from all cases of acute rejection and chronic rejection showed highly significant increases in immunostaining for the three TGF-beta isoforms (P < 0.001), fibronectin EDA+ (P < 0.005), and PAI-1 (P < 0.001). In the glomeruli, only TGF-beta 1 expression achieved statistical significance (P < 0.005) in acute rejection, whereas in chronic rejection, all three TGF-beta isoforms (p < 0.001) in addition to fibronectin EDA+ (p < 0.001) and PAI-1 (p < 0.001) were elevated. There was both cellular and matrix staining of the TGF-beta isoforms. In striking contrast, control kidney tissues were negative or only weakly positive. Because TGF-beta was present both in acute and in chronic rejection but not in control tissues and because acute rejection episodes are a good predictor for chronic rejection, these results suggest that TGF-beta may play a role in the pathogenesis of fibrosis in chronic rejection.