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Arthritis & Rheumatism | 2000

An interdisciplinary approach to the care of patients with Wegener's granulomatosis: Long-term outcome in 155 patients

Eva Reinhold-Keller; Nadja Beuge; Ute Latza; Kirsten de Groot; Heinrich Rudert; Bernhard Nölle; Martin Heller; Wolfgang L. Gross

OBJECTIVE To examine the outcome in 155 consecutive patients with Wegeners granulomatosis (WG) followed up for a median of 7 years. METHODS Treatment was adapted to the activity and extent of disease, with regular evaluation by an interdisciplinary team accompanied by group education about vasculitis. RESULTS The estimated median survival time was 21.7 years (95% confidence interval [95% CI] 15.60-27.86). Twenty-two patients died; 19 deaths were attributable to WG and/or its treatment. Significant predictors of survival at diagnosis were age >50 years (hazard ratio [HR] 5.45, 95% CI 1.97-15.02), kidney involvement with impaired renal function (HR 5.42, 95% CI 1.76-16.68), and lung involvement (HR 3.75, 95% CI 1.26-11.16). At some stage, 142 patients received prednisone and cyclophosphamide (CYC), usually as daily CYC plus mesna as uroprotection, 50 patients received trimethoprim/sulfamethoxazole, and 45 received methotrexate. Complete remission was achieved in 83 of the 155 patients. One or more relapses occurred in 99 patients after either complete or partial remission. CYC-induced cystitis and myelodysplastic syndrome occurred in 17 and 11 patients, respectively. A cumulative dose of 100 gm or more of CYC resulted in a 2-fold greater risk of CYC-related morbidity than with lower CYC doses. Serious infections occurred in 41 patients. CONCLUSION An interdisciplinary approach to the care of 155 WG patients resulted in a median survival of >21 years. Kidney or lung involvement at diagnosis was predictive of a >3-fold higher mortality. Although CYC remains essential in the treatment of WG, it was administered as briefly as possible and under close surveillance to avoid permanent CYC-related morbidity, which can lead to serious therapeutic problems in chronic relapsing WG.


Annals of Internal Medicine | 2009

Pulse Versus Daily Oral Cyclophosphamide for Induction of Remission in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis A Randomized Trial

Kirsten de Groot; Lorraine Harper; David Jayne; Luis Felipe Flores Suarez; Gina Gregorini; Wolfgang L. Gross; Rashid Luqmani; Charles D. Pusey; Niels Rasmussen; Renato Alberto Sinico; Vladimir Tesar; Philippe Vanhille; Kerstin Westman; Caroline O. S. Savage

Context Because cyclophosphamide has many adverse effects, dosing regimens that maintain efficacy but improve safety would be welcome. Contribution In this randomized comparison of pulse and daily oral cyclophosphamide regimens for treatment of ANCA-associated vasculitis, equal proportions of patients had remissions, but the pulse regimen seemed safer, mainly because it caused less leukopenia. Caution Patients and providers were not blinded to the intervention, and the study was not powered to detect differences in relapse rate. Implication The efficacy of pulse cyclophosphamide for treatment of ANCA-associated vasculitis seems no different from that of daily oral treatment and may be safer. The Editors Wegener granulomatosis, microscopic polyangiitis, and the renal-limited variant of microscopic polyangiitis are all associated with antineutrophil cytoplasmic antibodies (ANCAs) and are therefore referred to collectively as ANCA-associated vasculitis. The justification for grouping these diseases together as a single clinical entity goes beyond ANCA seropositivity; they cause similar histologic changes in the kidney, are associated with similar pathogenic autoantibodies, and respond similarly to induction immunosuppressive treatment. However, they also differ in important respects; for example, granuloma formation and relapse after treatment are more common in Wegener granulomatosis (1, 2). Outcomes for these previously fatal diseases improved dramatically with the introduction of daily oral cyclophosphamide therapy (3, 4). However, cyclophosphamide has significant adverse effects that influence long-term morbidity and mortality (5, 6). Strategies to reduce these adverse effects include reducing the duration of cyclophosphamide use to 3 to 6 months (maximum, 9 months) (2) and switching to an alternative immunosuppressive regimen after induction of remission and using methotrexate instead of cyclophosphamide in patients without generalized disease and significantly impaired renal function (7). For many patients, however, cyclophosphamide remains the mainstay of therapy for inducing remission and treating relapse, so regimens that maintain efficacy while minimizing cyclophosphamide dose and maximizing safety would be welcome. Previous studies (8) suggest that pulse cyclophosphamide regimens are safe and provide less cumulative cyclophosphamide exposure than daily oral cyclophosphamide regimens. However, small study sizes and variations in treatment regimens, including the use of treatments alongside cyclophosphamide, make the findings preliminary. We designed this trial to test the hypothesis that a regimen of pulsed intermittent cyclophosphamide would be as effective but less toxic than daily oral cyclophosphamide for inducing remission in patients with generalized ANCA-associated vasculitis with active glomerulonephritis. Methods Trial Design and Participants Our trial was an open-label, multicenter, randomized, controlled trial conducted over 18 months. Patients, providers, and the investigators who assessed trial outcomes were not blinded to treatment assignment. Our inclusion criteria were newly diagnosed Wegener granulomatosis, microscopic polyangiitis, or renal-limited microscopic polyangiitis (diagnostic criteria adapted from the 1992 Chapel Hill consensus conference [9] and our groups previous studies [2, 7, 1012]); renal involvement attributable to active vasculitis (as defined by at least 1 of the following: serum creatinine level >150 mol/L [>1.7 mg/dL] and 500 mol/L [5.7 mg/dL], biopsy demonstrating necrotizing glomerulonephritis, erythrocyte casts, or hematuria [>30 erythrocytes per high-power field] and proteinuria [>1 g/d]); and confirmatory histology or ANCA positivity. Our exclusion criteria were coexistence of other multisystem autoimmune disease; hepatitis B or C virus or HIV infection; serum creatinine level greater than 500 mol/L (>5.7 mg/dL); previous cancer; pregnancy; or age younger than 18 or older than 80 years. We conducted our study according to the Declaration of Helsinki. Informed consent was obtained from each participant, and each participating center reviewed the trial protocol and granted ethical approval. Random Assignment Random assignments were computer-generated and performed centrally by permuted blocks of 4, stratified by country and disease. Patients were enrolled by their treating physician and registered with the central trial coordinating office by fax submission of a form that contained information on center, date of birth, sex, disease, and creatinine level. We randomly assigned patients on a 1:1 basis to receive pulse or daily oral cyclophosphamide. Data were collected in record books, entered into a central computerized database, and validated against the record books before analysis. Eleven patients withdrew before random assignment; we randomly assigned 149 patients. Interventions We designed the pulse cyclophosphamide regimen by investigator consensus, on the basis of published experience with pulse cyclophosphamide in ANCA-associated vasculitis. Patients received 3 intravenous pulses of cyclophosphamide, 15 mg/kg, given 2 weeks apart, followed by pulses at 3-week intervals (15 mg/kg intravenously or 5 mg/kg orally on 3 consecutive days, at the physicians discretion) until remission, and then for another 3 months. The maximum dose per pulse was 1.2 g. We reduced the cyclophosphamide dose by 2.5 mg/kg per pulse for persons age 60 to 70 years, 5 mg/kg per pulse for persons older than 70 years, and 2.5 mg/kg per pulse for persons with a serum creatinine level of 300 to 500 mol/L (3.4 to 5.7 mg/dL). At minimum, blood counts were checked on day 10 and 14 after each pulse and immediately before the next pulse. We reduced the dose of the subsequent pulse by 20% for patients with a leukocyte nadir of 2 to 3109/L and 40% for those with a nadir of 1 to 2109/L. The daily oral cyclophosphamide group received cyclophosphamide, 2 mg/kg per day, until remission, followed by 1.5 mg/kg per day for another 3 months. The maximum oral dose was 200 mg, and we reduced the dose by 25% for persons older than 60 years and 50% for those older than 70 years. At minimum, blood counts were checked weekly for the first month, twice-weekly for the second month, and monthly thereafter. We withheld cyclophosphamide for persons with a leukocyte count less than 4109/L, then resumed therapy at a dose reduced by 25 mg/d when their count increased to greater than 4109/L. Both groups continued the cyclophosphamide regimens for 3 months after remission, after which all patients received azathioprine, 2 mg/kg per day orally, until month 18 for remission maintenance. The maximum daily oral dose of azathioprine was 200 mg. Both groups also received prednisolone, 1 mg/kg orally, tapered to 12.5 mg at the end of month 3 and to 5 mg at the end of the study (month 18). 2-Mercaptoethanesulfonate sodium was optional in both groups. No patients received plasmapheresis. We recommended prophylaxis for Pneumocystis jiroveci for all patients. Treatment was allowed to follow local practice for patients who did not achieve remission at 9 months. We collected data on these patients but censored them for purposes of this analysis. For more details on the protocol, see Appendix 1. Outcomes and Follow-up We defined outcomes by using the Birmingham Vasculitis Activity Score (BVAS) index, which measures manifestations of active vasculitis during the 28 days before the date of assessment (13). Our primary outcome was time to remission, defined as the absence of new or worse signs of disease activity on the BVAS and no more than 1 item indicating persistent disease activity (BVAS 1). Secondary outcomes included the proportion of patients who achieved remission at 6 and 9 months and the proportion with major and minor relapses. We defined major relapse as the recurrence or first appearance of at least 1 BVAS item indicating threatened vital organ function attributable to active vasculitis. We defined minor relapse as the recurrence or first appearance of at least 3 other BVAS items related to nonvital organs. An investigator classified patients as achieving remission or having relapse, and an independent observer validated these classifications retrospectively. Additional secondary outcomes were death; change in renal function; adverse events, including leukopenia and infection; and the cumulative dose of cyclophosphamide and prednisolone, which we calculated as the total cumulative drug dose at each time point in the study (3, 6, 9, 12, 15, and 18 months) divided by the number of patients in the study at that point. For each time point, we considered only the dose of drug for those patients still in the study. Unless otherwise noted, we assessed these outcomes at baseline; at 1.5, 3, 4.5, 6, 7.5, 9, 12, 15, and 18 months after baseline; and at relapse, on the basis of standard recommendations. Clinical assessments included BVAS measures at every visit and measures of cumulative damage from any cause since disease onset, as scored by the Vasculitis Damage Index (14), at baseline and every 3 months. Laboratory assessments included measures of full blood count, C-reactive protein, alanine transaminase, serum creatinine, and glucose, as well as dipstick urine analysis. We calculated glomerular filtration rate at entry, remission, and study end by using the Modification of Diet in Renal Disease method (15). Statistical Analysis We determined the sample size for the trial by clinical rather than statistical considerations. We set a recruitment goal of 160 patients; we considered that number ambitious, given the rarity of these conditions (12 per 1 million persons) and the need to recruit patients and conduct the trial within a period (5 years) that was reasonable for our resources. We performed analyses by intention to treat. To account for censoring, we compared remission and survival by using survival methods instead of relat


JAMA | 2010

Mycophenolate Mofetil vs Azathioprine for Remission Maintenance in Antineutrophil Cytoplasmic Antibody–Associated Vasculitis: A Randomized Controlled Trial

Thomas F. Hiemstra; Michael P. Walsh; Alfred Mahr; Caroline O. S. Savage; Kirsten de Groot; Lorraine Harper; Thomas H. Hauser; Irmgard Neumann; Vladimir Tesar; Karl Martin Wissing; Christian Pagnoux; Wilhelm H. Schmitt; David Jayne

CONTEXT Current remission maintenance therapies for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) are limited by partial efficacy and toxicity. OBJECTIVE To compare the effects of mycophenolate mofetil with azathioprine on the prevention of relapses in patients with AAV. DESIGN, SETTING, AND PARTICIPANTS Open-label randomized controlled trial, International Mycophenolate Mofetil Protocol to Reduce Outbreaks of Vasculitides (IMPROVE), to test the hypothesis that mycophenolate mofetil is more effective than azathioprine for preventing relapses in AAV. The trial was conducted at 42 centers in 11 European countries between April 2002 and January 2009 (42-month study). Eligible patients had newly diagnosed AAV (Wegener granulomatosis or microscopic polyangiitis) and were aged 18 to 75 years at diagnosis. INTERVENTIONS Patients were randomly assigned to azathioprine (starting at 2 mg/kg/d) or mycophenolate mofetil (starting at 2000 mg/d) after induction of remission with cyclophosphamide and prednisolone. MAIN OUTCOME MEASURES The primary end point was relapse-free survival, which was assessed using a Cox proportional hazards model. The secondary end points were Vasculitis Damage Index, estimated glomerular filtration rate, and proteinuria. RESULTS A total of 156 patients were assigned to azathioprine (n = 80) or mycophenolate mofetil (n = 76) and were followed up for a median of 39 months (interquartile range, 0.66-53.6 months). All patients were retained in the analysis by intention to treat. Relapses were more common in the mycophenolate mofetil group (42/76 patients) compared with the azathioprine group (30/80 patients), with an unadjusted hazard ratio (HR) for mycophenolate mofetil of 1.69 (95% confidence interval [CI], 1.06-2.70; P = .03). Severe adverse events did not differ significantly between groups. There were 22 severe adverse events in 13 patients (16%) in the azathioprine group and there were 8 severe adverse events in 8 patients (7.5%) in the mycophenolate mofetil group (HR, 0.53 [95% CI, 0.23-1.18]; P = .12). The secondary outcomes of Vasculitis Damage Index, estimated glomerular filtration rate, and proteinuria did not differ significantly between groups. CONCLUSIONS Among patients with AAV, mycophenolate mofetil was less effective than azathioprine for maintaining disease remission. Both treatments had similar adverse event rates. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00307645.


Annals of the Rheumatic Diseases | 2011

Long-term patient survival in ANCA-associated vasculitis

Oliver Flossmann; Annelies E. Berden; Kirsten de Groot; Chris Hagen; Lorraine Harper; Caroline Heijl; Peter Höglund; David Jayne; Raashid Luqmani; Alfred Mahr; Chetan Mukhtyar; Charles D. Pusey; Niels Rasmussen; Coen A. Stegeman; Michael Walsh; Kerstin Westman

Background Wegeners granulomatosis and microscopic polyangiitis are antineutrophil cytoplasm antibodies (ANCA)-associated vasculitides with significant morbidity and mortality. The long-term survival of patients with ANCA associated vasculitis treated with current regimens is uncertain. Objective To describe the long-term patient survival and possible prognostic factors at presentation in an international, multicentre, prospectively recruited representative patient cohort who were treated according to strictly defined protocols at presentation and included the full spectrum of ANCA-associated vasculitis disease. Methods Outcome data were collected for 535 patients who had been recruited at the time of diagnosis to four randomised controlled trials between 1995 and 2002. Trial eligibility was defined by disease severity and extent, covered the spectrum of severity of ANCA-associated vasculitis and used consistent diagnostic criteria. Demographic, clinical and laboratory parameters at trial entry were tested as potential prognostic factors in multivariable models. Results The median duration of follow-up was 5.2 years and 133 (25%) deaths were recorded. Compared with an age- and sex-matched general population there was a mortality ratio of 2.6 (95% CI 2.2 to 3.1). Main causes of death within the first year were infection (48%) and active vasculitis (19%). After the first year the major causes of death were cardiovascular disease (26%), malignancy (22%) and infection (20%). Multivariable analysis showed an estimated glomerular filtration rate <15 ml/min, advancing age, higher Birmingham Vasculitis Activity Score, lower haemoglobin and higher white cell count were significant negative prognostic factors for patient survival. Conclusion Patients with ANCA-associated vasculitis treated with conventional regimens are at increased risk of death compared with an age- and sex-matched population.


Hypertension | 2005

Stimulation of Endothelial Progenitor Cells: A New Putative Therapeutic Effect of Angiotensin II Receptor Antagonists

Ferdinand H. Bahlmann; Kirsten de Groot; Ottfried Mueller; Barbara Hertel; Hermann Haller; Danilo Fliser

The number of circulating endothelial progenitor cells (EPCs) correlates with endothelial dysfunction and cardiovascular risk in humans. We explored whether angiotensin II receptor antagonist therapy affects the number of regenerative EPCs in patients with type 2 diabetes. In a prospective double-blind parallel group study, we randomly treated 18 type 2 diabetics with olmesartan (40 mg) or placebo for 12 weeks. We analyzed circulating CD34+ hematopoietic progenitor cells (flow cytometry) and EPCs (in vitro assay) before and after therapy. We verified the results in a second open trial treating 20 type 2 diabetics with 300 mg of irbesartan for 12 weeks. The number of EPCs was significantly lower in diabetic patients as compared with 38 age-matched healthy subjects (210±10 versus 258±18 per high-power field; P<0.05), whereas there was no significant difference with respect to hematopoietic progenitor cells. Treatment with olmesartan (n=9) significantly increased EPCs from 231±24 to 465±71 per high-power field (P<0.05), but not hematopoietic progenitor cells. In contrast, placebo treatment (n=9) did not affect EPCs and hematopoietic progenitor cells. With irbesartan therapy, EPC number increased significantly from 196±15 to 300±23 per high-power field (P<0.05) already after 4 weeks of treatment. At the end of 12-week therapy, patients had 310±23 EPCs per high-power field (P<0.05 versus baseline). Angiotensin II receptor antagonists increase the number of regenerative EPCs in patients with type 2 diabetes mellitus. This action may be of therapeutic relevance contributing to their beneficial cardiovascular effects.


Annals of the Rheumatic Diseases | 2012

Pulse versus daily oral cyclophosphamide for induction of remission in ANCA-associated vasculitis: long-term follow-up

Lorraine Harper; Matthew D. Morgan; Michael P. Walsh; Peter Höglund; Kerstin Westman; Oliver Flossmann; Vladimir Tesar; Phillipe Vanhille; Kirsten de Groot; Raashid Luqmani; Luis Felipe Flores-Suárez; Richard A. Watts; Charles D. Pusey; Annette Bruchfeld; Niels Rasmussen; Daniel Engelbert Blockmans; Caroline O. S. Savage; David Jayne

Introduction The previously reported randomised controlled trial of a consensus regimen of pulse cyclophosphamide suggested that it was as effective as a daily oral (DO) cyclophosphamide for remission induction of antineutrophil cytoplasm autoantibodies-associated systemic vasculitis when both were combined with the same glucocorticoid protocol (CYCLOPS study (Randomised trial of daily oral versus pulse Cyclophosphamide as therapy for ANCA-associated Systemic Vasculitis published de groot K, harper L et al Ann Int Med 2009)). The study had limited power to detect a difference in relapse. This study describes the long-term outcomes of patients in the CYCLOPS study. Methods Long-term outcomes were ascertained retrospectively from 148 patients previously recruited to the CYCLOPS Trial. Data on survival, relapse, immunosuppressive treatment, cancer incidence, bone fractures, thromboembolic disease and cardiovascular morbidity were collected from physician records retrospectively. All patients were analysed according to the group to which they were randomised. Results Median duration of follow-up was 4.3 years (IQR, 2.95–5.44 years). There was no difference in survival between the two limbs (p=0.92). Fifteen (20.8%) DO and 30 (39.5%) pulse patients had at least one relapse. The risk of relapse was significantly lower in the DO limb than the pulse limb (HR=0.50, 95% CI 0.26 to 0.93; p=0.029). Despite the increased risk of relapse in pulse-treated patients, there was no difference in renal function at study end (p=0.82). There were no differences in adverse events between the treatment limbs. Discussion Pulse cyclophosphamide is associated with a higher relapse risk than DO cyclophosphamide. However, this is not associated with increased mortality or long-term morbidity. Although the study was retrospective, data was returned in 90% of patients from the original trial.


Annals of the Rheumatic Diseases | 2008

Development of comprehensive disease assessment in systemic vasculitis

Oliver Flossmann; P. A. Bacon; Kirsten de Groot; David Rw Jayne; Niels Rasmussen; Philip Seo; Kerstin Westman; R Luqmani

The systemic vasculitides are multisystem disorders with considerable mortality and morbidity and frequent relapses. In the absence of reliable serological markers, accurate clinical tools are required to assess disease activity and damage for treatment decisions, and for the performance of clinical trials. This article reviews and summarises the development and use of disease assessment tools for determining activity and damage in systemic vasculitis and reports ongoing initiatives for further development of disease assessment tools. A literature search was conducted using PubMed and reference lists for vasculitis, assessment, clinical trials, outcome and prognosis. The findings indicate that comprehensive disease assessment in vasculitis requires documentation of disease activity, chronic irreversible damage and impairment of function.


Arthritis & Rheumatism | 2012

Brief Report: Long-term outcome of a randomized clinical trial comparing methotrexate to cyclophosphamide for remission induction in early systemic antineutrophil cytoplasmic antibody–associated vasculitis

Mikkel Faurschou; Kerstin Westman; Niels Rasmussen; Kirsten de Groot; Oliver Flossmann; Peter Höglund; David Jayne

OBJECTIVE The NORAM (Nonrenal Wegeners Granulomatosis Treated Alternatively with Methotrexate [MTX]) trial demonstrated that MTX can replace cyclophosphamide (CYC) as remission-inducing treatment for patients with newly diagnosed early systemic antineutrophil cytoplasmic antibody-associated vasculitis. Duration of relapse-free survival was longer among CYC-treated patients than among MTX-treated patients during short-term followup. The aim of the present study was to describe the long-term outcome in patients enrolled in the randomized clinical trial. METHODS Outcome questionnaires were sent to investigators who had recruited patients for the NORAM trial. Patients treated with MTX for induction of remission (n = 49) were compared to CYC-treated patients (n = 46) with respect to immunosuppressive therapy during followup, relapse-free survival, mortality, and occurrence of other clinical events. RESULTS The median duration of followup was 6 years (range 0.1-10.8 years). One patient developed end-stage renal disease, and 11 died. The number of patients affected by serious infection, malignancy, or severe organ failure did not differ between treatment groups, and no difference in survival rate was observed. The duration of corticosteroid therapy was longer in the MTX group during the 18 months of the trial (P = 0.005). During subsequent followup, patients who were in the MTX group in the NORAM trial received corticosteroids, CYC, and other immunosuppressive agents (azathioprine, MTX, and/or mycophenolate mofetil) for longer periods than those who were in the CYC group (P = 0.004, P = 0.037, and P = 0.031, respectively). The cumulative relapse-free survival tended to be lower in the MTX group (P = 0.056). CONCLUSION In the NORAM cohort, no difference in occurrence of major adverse events was observed between treatment groups during long-term followup. However, first-line treatment with MTX was associated with less effective disease control than CYC-based induction therapy.


Clinical Journal of The American Society of Nephrology | 2006

Pharmacokinetics of Moxifloxacin and Levofloxacin in Intensive Care Unit Patients Who Have Acute Renal Failure and Undergo Extended Daily Dialysis

David Czock; Cordula Hüsig-Linde; Anita Langhoff; Timo Schöpke; Carsten Hafer; Kirsten de Groot; Stefanie Swoboda; Ernst Kuse; Hermann Haller; Danilo Fliser; Frieder Keller; Jan T. Kielstein

Extended daily dialysis (EDD) is increasingly popular in the treatment of acute renal failure (ARF). EDD could remove drugs to a much different degree compared with intermittent standard hemodialysis or continuous renal replacement therapies; however, there are only scarce data on how EDD influences the pharmacokinetics of frequently used drugs. The aim of this study was to determine the pharmacokinetics of two quinolone antibiotics in patients who had anuric ARF and were being treated with EDD. Adult patients who were in the intensive care unit at a tertiary care university hospital and receiving moxifloxacin (n = 10) or levofloxacin (n = 5) therapy were included. The antibiotics were administered intravenously 8 h (400 mg of moxifloxacin) or 12 h (500 mg of levofloxacin) before EDD to study pharmacokinetics off and on EDD. Treatment lasted 8 h; blood and dialysate flow rates were 160 ml/min. In addition to standard pharmacokinetic parameters, the total dialysate concentration of both drugs was measured using a technically simple single-pass batch dialysis system for EDD. Moxifloxacin pharmacokinetics in critically ill patients who had ARF and were undergoing EDD were similar to those in healthy subjects without renal impairment. Levofloxacin, although removed by EDD, had a lower total clearance compared with healthy subjects. According to these findings, anuric critically ill patients who are undergoing EDD should be treated with the standard dosage of moxifloxacin (400 mg/d intravenously). The levofloxacin dosage, however, should be reduced according to the intensity of renal replacement therapy.


Journal of The American Society of Nephrology | 2006

IGF-Binding Protein-3 Modulates TGF-β/BMP-Signaling in Glomerular Podocytes

Imke Peters; Irini Tossidou; Johannes Achenbach; Robert P. Woroniecki; Michael Mengel; Joon-Keun Park; Melanie Paschy; Kirsten de Groot; Hermann Haller; Mario Schiffer

Podocyte apoptosis initiates progressive glomerulosclerosis in TGF-beta1 transgenic and CD2AP-knockout (CD2AP-/-) mice. It was previously shown that in both mouse models, activation of the TGF-beta pathway is the key event during development of podocyte apoptosis. Furthermore, CD2AP is an important modifier of TGF-beta-induced survival signaling via activation of the phosphoinositol 3-kinase/AKT signaling pathway. This article presents IGF-binding protein-3 (IGFBP-3) as a new modulator of apoptosis and survival signaling in glomerular podocytes. High expression of IGFBP-3 protein in the urine of diseased CD2AP-/- mice was discovered, and IGFBP-3 expression in glomerular podocytes and parietal cells was detected. IGFBP-3 can induce changes in podocyte actin cytoskeleton, leads to apoptosis in cultured murine podocytes, and can enhance TGF-beta1-induced apoptosis in vitro. For studying this process on a molecular level, proapoptotic p38 mitogen-activated protein kinase pathways and antiapoptotic phosphoinositol 3-kinase/AKT pathways were examined in cultured murine podocytes. It was found that IGFBP-3 increments the level of TGF-beta1-induced phosphorylated p38 mitogen-activated protein kinase and decreases the phosphorylation of antiapoptotic AKT. This effect is specific for the co-stimulation of IGFBP-3 with TGF-beta1 because a combination of IGFBP-3 with bone morphogenic protein-7 (BMP-7), another member of the TGF-beta superfamily, results in apoptosis opposing signaling effects with a strong increase of phosphorylated AKT and subsequent functional effects. These results demonstrate that the IGF/IGFBP axis plays an important role in the development of podocyte apoptosis by modulation of TGF-beta and BMP-7-induced pro- and antiapoptotic signals.

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David Jayne

University of Cambridge

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