Renal disease in sarcoidosis patients in a German multicentric retrospective cohort study.

INTRODUCTION: Sarcoidosis is a systemic granulomatous disease potentially affecting every organ system. Renal involvement is reportedly rare, and the evidence consists of case reports and cohort studies. Systematic investigations are scarce and show a varying prevalence ranging from <1% to 30-50%. METHODS: We retrospectively analyzed data from patients with a recent diagnosis of sarcoidosis from five tertiary care centers focusing on renal sarcoidosis. RESULTS: We analyzed data from 327 patients with sarcoidosis between 2001 and 2021. Of 327 patients, 109 (33.3%) had probable or definite renal sarcoidosis. 90 (27.5%) had histopathologic confirmation. 57 (64%) had an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2. The most prominent associated finding was an elevated soluble interleukin-2 receptor. Patients with renal sarcoidosis more frequently received glucocorticoids than other non-renal sarcoidosis patients (92% vs. 78%, p < 0.01). Also, azathioprine (38% vs. 16%, p < 0.001) and mycophenolate mofetil (5% vs. 1%, p < 0.05) were more frequently used in renal sarcoidosis compared to non-renal sarcoidosis, whereas methotrexate was used less frequently (7% vs. 17%, p < 0.05). CONCLUSIONS: Our data of the largest cohort with biopsy-confirmed renal sarcoidosis demonstrate a higher prevalence (27.5% of all patients) than previously published with a relevant disease burden. The urinary findings in most cases were only mildly abnormal, and some patients did not have renal biopsy despite abnormal urinary results. A renal workup should be performed in all patients with a new diagnosis of sarcoidosis.

COVID-19 pandemic impairs medical care of vasculitis patients in Germany: Results of a national patient survey.

Objective: To analyze the impact of the COVID-19 pandemic on medical care and vaccination acceptance of vasculitis patients in Germany. Methods: A web-based national survey was developed by rheumatology centers and vasculitis patient advocacy groups. The survey was distributed nationwide by mail and flyers and could be accessed via a QR-code or weblink from December 2021 to April 2022. Descriptive statistics [mean, median, standard derivation (SD), 25%, 75% quantile] were calculated. 95% confidence intervals were presented for responses that were directly related to the impact of COVID-19 on parameters associated with vasculitis patient care. Results: The online survey was completed by 117 patients with small and large vessel vasculitis [granulomatosis with polyangiitis (n = 69), eosinophilic granulomatosis with polyangiitis (n = 16), microscopic polyangiitis (n = 12), giant cell arteritis (n = 17) and Takayasu's arteritis (n = 3)]. Prescheduled rheumatological appointments had been canceled due to the COVID-19 pandemic in 12.6% of the respondents [95% confidence interval (CI), 7.3-20.0%); in 9% (95% CI, 4.5-15.6%)] appointments had been replaced by digital services. Therapeutic regimens were changed (shifted, reduced, or discontinued) due to the pandemic in 15.5% (95% CI 9.5-22.2%). Vaccination coverages were generally high compared to patients with other rheumatic diseases and the general population. Highest vaccination coverage was observed against COVID-19 (98.1% 95% CI 93.9-99.6%). Conclusion: Vasculitis patients experienced changes in medical care during COVID-19 pandemic such as cancelation of prescheduled rheumatology appointments and modifications in therapeutic regimens. The overall acceptance rate for vaccination was comparatively high, particularly for vaccination against COVID-19.

[Anti B-cell-antibody treatment for maintenance of remission in granulomatosis with polyangiitis and microscopic polyangiitis]. / Anti-B-Zell-Antikörpertherapie zur Remissionserhaltung bei Granulomatose mit Polyangiitis und mikroskopischer Polyangiitis.

Granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) are the most frequent primary necrotizing small vessel vasculitides. In these formerly fatal diseases remission can be induced by stage- and activity-adapted immunosuppressive regimens in the majority of patients. This does not lead to drug-free long-term remission or even cure. Consequently, maintenance of remission medication is needed. Recent randomized controlled trials demonstrated that maintenance treatment with the anti-B-cell antibody Rituximab, administered 6-monthly as opposed to azathioprine leads to a significantly lower relapse rate but a similar profile of adverse events. These data enabled the extension of the approval of Rituximab for maintenance of remission treatment of GPA and MPA in Germany in 2018. Guidelines and expert recommendations concerning measures of infection prevention and vaccination of immunosuppressed patients as well as the management of hypogammaglobulinemia and cytopenia on Rituximab are presented in this review.

[A rare manifestation of an inflammatory rheumatic systemic disease]. / Eine seltene Manifestation einer entzündlich rheumatischen Systemerkrankung.

Granulomatosis with polyangiitis (GPA) is an ANCA(anti-neutrophil cytoplasmatic antibody)-associated small vessel vasculitis usually affecting the respiratory tract and the kidneys. This article reports on a 46-year-old male patient with a rare organ manifestation pattern of GPA: besides a fulminantly progressive tetraparesis the patient suffered from severe ulcerative colitis. The early diagnosis of GPA with unusual findings and its delineation from a septic event is essential.

Treatment of ANCA-associated vasculitis.

Antineutrophil cytoplasmic autoantibody (ANCA)-associated diseases are small-vessel vasculitides, encompassing granulomatosis with polyangiitis (formerly Wegener's granulomatosis), microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis. Once considered life-threatening diseases, the introduction of stage-adapted immunosuppressive therapy and medications with decreased toxicity has improved patients' survival. Treatment is biphasic, consisting of induction of remission (3-6 months) for rapid control of disease activity and maintenance of remission (at least 18 months) to prevent disease relapse using therapeutic alternatives that have reduced toxicity. This Review summarizes current treatment strategies for these diseases, with a special focus on long-term follow-up data from key randomized controlled trials and new developments in remission induction and maintenance therapy. Current treatment strategies have substantial short-term and long-term adverse effects, and relapses are frequent; thus, less-toxic and more-effective approaches are needed. Moreover, the optimal intensity and duration of maintenance therapy remains under debate. Clinical trials have traditionally considered ANCA-associated vasculitides as a single disease entity. However, future studies must stratify participants according to their specific disease, clinical features (different types of organ manifestation, PR3-ANCA or MPO-ANCA positivity) and disease severity.

Renal disease in small-vessel vasculitis.

Glomerulonephritis (GN) is a common manifestation of the antineutrophil cytoplasmic antibody-associated systemic vasculitides (AASV), which include granulomatosis with polyangiitis and microscopic polyangiitis. The level of renal involvement at presentation is highly predictive of survival and should be assessed early so that kidney function can be preserved. AASV patients with urinary sediment but normal function have a twofold greater risk of death than those with no renal involvement. Those with impaired renal function at diagnosis have a fivefold greater risk of death. Renal vasculitis is most prevalent in older patients, who have more severe disease and poorer prognoses. Renal biopsy not only establishes diagnosis but provides information on severity of renal-function impairment and prognosis. Induction of remission with cyclophosphamide is standard treatment. For patients with crescentic, rapidly progressive GN, adjunctive plasma exchange can promote renal recovery. Renal failure occurs in one-fourth of AASV patients after 3 to 4 years; 60% of patients receiving dialysis for acute GN can recover independent renal function. Renal transplant patients with vasculitis fare as well as renal transplant patients without vasculitis. Lastly, renal vasculitis is an independent risk factor for cardiovascular events.

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.

OBJECTIVE: The NORAM (Nonrenal Wegener's 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.

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

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.

TLR-4+ peripheral blood monocytes and cardiovascular events in patients with chronic kidney disease--a prospective follow-up study.

BACKGROUND: Atherosclerosis is an inflammatory process mediated by circulating immune cells, including monocytes. There is accumulating evidence for the involvement of Toll-like receptor 4 (TLR-4) as a mediator of atherogenesis. METHODS: We evaluated the association between CD14+/TLR-4+ monocytes in peripheral blood (flow cytometry) and future cardiovascular events (CVE), e.g. myocardial infarction, percutaneous transluminal coronary angioplasty (including stenting), aortocoronary bypass, stroke and angiographically verified stenosis of peripheral arteries and cardiovascular (CV) death, in 191 patients with chronic kidney disease Stage V receiving hemodialysis therapy. RESULTS: At baseline, CD14+/TLR-4+ monocytes correlated significantly with age (r = 0.2; P = 0.007), high-sensitivity C-reactive protein (r = 0.2; P = 0.008) and mean arterial pressure (r = -0.2; P = 0.02), but not with gender (P = 0.5), smoking (P = 0.6) and the presence of diabetes (P = 0.5). During a median follow-up period of 36 [1-54] months, 79 (41%) patients experienced a CVE. A total of 55 patients died during the follow-up period, 25 of those due to a confirmed CV cause. Log-rank test did not reveal statistical significance for TLR-4+ monocytes concerning incident CVE (P = 0.3), CV death (P = 0.85) and overall death (P = 0.8). In a multiple Cox-regression analysis, we identified age (P = 0.003) and smoking (P = 0.001) as the only independent variables associated with incident CVE. CONCLUSIONS: Unexpectedly, we could not detect an association between CD14+/TLR-4+ monocytes and incident CVE as well as CV death in stable hemodialysis patients. Further studies have to clarify the potential role of this cell population for CV outcome in this population.

Long-term patient survival in ANCA-associated vasculitis.

BACKGROUND: Wegener's 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.

Mycophenolate mofetil vs azathioprine for remission maintenance in antineutrophil cytoplasmic antibody-associated vasculitis: a randomized controlled trial.

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.

Endothelial progenitor cells and cardiovascular events in patients with chronic kidney disease--a prospective follow-up study.

BACKGROUND: Endothelial progenitor cells (EPCs) mediate vascular repair and regeneration. Their number in peripheral blood is related to cardiovascular events in individuals with normal renal function. METHODS: We evaluated the association between functionally active EPCs (cell culture) and traditional cardiovascular risk factors in 265 patients with chronic kidney disease stage V receiving hemodialysis therapy. Thereafter, we prospectively assessed cardiovascular events, e.g. myocardial infarction, percutaneous transluminal coronary angioplasty (including stenting), aorto-coronary bypass, stroke and angiographically verified stenosis of peripheral arteries, and cardiovascular death in this cohort. RESULTS: In our patients EPCs were related only to age (r=0.154; p=0.01). During a median follow-up period of 36 months 109 (41%) patients experienced a cardiovascular event. In a multiple Cox regression analysis, we identified EPCs (p=0.03) and patient age (p=0.01) as the only independent variables associated with incident cardiovascular events. Moreover, a total of 70 patients died during follow-up, 45 of those due to cardiovascular causes. Log rank test confirmed statistical significance for EPCs concerning incident cardiovascular events (p=0.02). CONCLUSIONS: We found a significant association between the number of functionally active EPCs and cardiovascular events in patients with chronic kidney disease. Thus, defective vascular repair and regeneration may be responsible, at least in part, for the enormous cardiovascular morbidity in this population.

EULAR points to consider in the development of classification and diagnostic criteria in systemic vasculitis.

OBJECTIVES: The systemic vasculitides are multiorgan diseases where early diagnosis and treatment can significantly improve outcomes. Robust nomenclature reduces diagnostic delay. However, key aspects of current nomenclature are widely perceived to be out of date, these include disease definitions, classification and diagnostic criteria. Therefore, the aim of the present work was to identify deficiencies and provide contemporary points to consider for the development of future definitions and criteria in systemic vasculitis. METHODS: The expert panel identified areas of concern within existing definitions/criteria. Consequently, a systematic literature review was undertaken looking to address these deficiencies and produce 'points to consider' in accordance with standardised European League Against Rheumatism (EULAR) operating procedures. In the absence of evidence, expert consensus was used. RESULTS: There was unanimous consensus for re-evaluating existing definitions and developing new criteria. A total of 17 points to consider were proposed, covering 6 main areas: biopsy, laboratory testing, diagnostic radiology, nosology, definitions and research agenda. Suggestions to improve and expand current definitions were described including the incorporation of anti-neutrophil cytoplasm antibody and aetiological factors, where known. The importance of biopsy in diagnosis and exclusion of mimics was highlighted, while equally emphasising its problems. Thus, the role of alternative diagnostic tools such as MRI, ultrasound and surrogate markers were also discussed. Finally, structures to develop future criteria were considered. CONCLUSIONS: Limitations in current classification criteria and definitions for vasculitis have been identified and suggestions provided for improvement. Additionally it is proposed that, in combination with the updated evidence, these should form the basis of future attempts to develop and validate revised criteria and definitions of vasculitis.

Toll-like receptor 2 and renal allograft function.

BACKGROUND: Toll-like receptors (TLR) modulate the immune response. We analyzed the relationships between TLR expression in renal tissue with infection, rejection and graft function after kidney transplantation. METHODS: TLR-2 and TLR-4 expression was detected by immunohistochemistry in 257 protocol biopsies obtained 6 weeks, 3 and 6 months after transplantation, and in 108 indication biopsies. We correlated TLR expression in different renal tissue compartments with kidney transplant function 6, 12 and 24 months after transplantation, acute cellular rejection in renal grafts (according to the Banff classification), and urinary tract and cytomegalovirus infections. RESULTS: We found a highly consistent correlation of TLR-2 expression in proximal and distal tubules, and in renal vessels (p < 0.001 for all compartments), but not for TLR-4 expression. This holds true for all protocol biopsy time points as well as for indication biopsies. Positive TLR-2 expression in renal tubules was associated with significantly (p < 0.05) better initial graft function as well as graft function 6, 12 and 24 months after transplantation. We also found a significant (p < 0.05) association between TLR-2 expression and lower incidence of acute cellular rejection in early protocol biopsies (6 weeks). In contrast, positive TLR-4 expression was not related to kidney function or acute cellular rejection. Further, the two different TLR subtypes were not related to episodes of urinary tract or cytomegalovirus infections. CONCLUSION: TLR-2 expression in renal tissue is associated with superior graft function up to 2 years after kidney transplantation. The role of TLR-2 in the immune response against human kidney transplants warrants further investigation.

Simvastatin versus ezetimibe: pleiotropic and lipid-lowering effects on endothelial function in humans.

BACKGROUND: Statins may exert important pleiotropic effects, ie, improve endothelial function, independently of their impact on LDL cholesterol. In humans, however, pleiotropic effects of statins have never been unequivocally demonstrated because prolonged statin treatment always results in reduced LDL cholesterol levels. We therefore tested the hypothesis that similar reductions in LDL cholesterol with simvastatin and ezetimibe, a novel cholesterol absorption inhibitor, result in different effects on endothelial function. METHODS AND RESULTS: Twenty patients with chronic heart failure were randomized to 4 weeks of simvastatin (10 mg/d) or ezetimibe (10 mg/d) treatment. Flow-dependent dilation (FDD) of the radial artery was determined by high-resolution ultrasound before and after intra-arterial vitamin C to determine the portion of FDD inhibited by radicals (DeltaFDD-VC). Activity of extracellular superoxide dismutase, a major vascular antioxidant enzyme system, was determined after release from the endothelium by a heparin bolus injection. Endothelial progenitor cells were analyzed with an in vitro assay. Simvastatin and ezetimibe treatment reduced LDL cholesterol to a similar extent (15.6% versus 15.4%; P=NS), whereas changes in mevalonate, the product of HMG-CoA-reductase, differed between groups (Deltamevalonate-simvastatin, -1.04+/-0.62 versus Deltamevalonate-ezetimibe, 1.79+/-0.94 ng/mL; P<0.05 between groups). Importantly, FDD was markedly improved after simvastatin (10.5+/-0.6% versus 5.1+/-0.7%; P<0.01) but not after ezetimibe treatment (5.6+/-0.5% versus 5.8+/-0.6%; P=NS). DeltaFDD-VC was substantially reduced after simvastatin but not after ezetimibe treatment. Extracellular superoxide dismutase activity was increased by >100% (P<0.05) after simvastatin but not ezetimibe treatment. Simvastatin treatment increased the number of functionally active endothelial progenitor cells, whereas ezetimibe had no effect. CONCLUSIONS: Four weeks of simvastatin treatment improves endothelial function independently of LDL cholesterol lowering, at least in part by reducing oxidant stress. Simvastatin may thereby exert important pleiotropic effects in humans.

Kidney graft function determines endothelial progenitor cell number in renal transplant recipients.

BACKGROUND: Circulating bone marrow-derived endothelial progenitor cells (EPCs) promote vascular repair, and their number correlates with endothelial function and cardiovascular risk in humans. In uremic patients, the number of functionally active EPCs is reduced. Thus, we assessed EPCs in stable patients 6 months or more after renal transplantation. METHODS: We analyzed circulating CD34+ hematopoietic progenitor cells (HPCs) using flow cytometry and EPCs (in vitro assay) in 74 renal transplant patients (51.6+/-11.5 years; 46 males), 74 age-matched healthy subjects, and 29 patients with preterminal renal failure. RESULTS: EPC numbers were similar in renal transplant recipients and controls (232+/-92 vs. 250+/-103/high power field; n.s.), but were significantly higher than in uremic patients (160+/-97/high power field; P=0.004). In addition, transplant recipients had more HPCs than controls (2.71+/-1.65 vs. 1.99+/-1.12 /microl; P=0.004) and uremic patients (1.64+/-0.96/microl; P=0.001). EPCs in renal transplant recipients correlated significantly with graft function(that is, Cockcroft-Gault clearance [r=0.294; P=0.012]), but not with age or HPCs. Moreover, in the multiple regression analysis, graft function (r=0.332; P=0.01) and diastolic blood pressure (r=-0.278; P=0.03) were independent predictors of EPCs. In vitro, sera from renal transplant recipients with poor graft function significantly inhibited EPC differentiation compared with sera from patients with a clearance above 50 mL/min (151+/-54 vs. 274+/-94 EPCs/high power field; P=0.02). CONCLUSIONS: EPC numbers in stable renal transplant recipients are comparable to those found in healthy subjects. In addition, graft function is a significant determinant of EPCs. Prospective studies should explore whether improvement of EPCs influences cardiovascular risk in renal transplant recipients.

Stimulation of endothelial progenitor cells: a new putative therapeutic effect of angiotensin II receptor antagonists.

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.

Low-dose therapy with the long-acting erythropoietin analogue darbepoetin alpha persistently activates endothelial Akt and attenuates progressive organ failure.

BACKGROUND: The hematopoietic cytokine erythropoietin has cytoprotective effects in endothelial cells in vitro that are mediated through direct activation of the pro-survival Akt tyrosine kinase signaling pathway. We tested the hypothesis that low-dose therapy with the long-acting recombinant human erythropoietin analogue darbepoetin alpha protects vascular endothelium in vivo in a classic remnant kidney rat model characterized by severe endothelial damage, progressive vascular sclerosis, and ischemia-induced tissue fibrosis. METHODS AND RESULTS: Using a parallel group study design, we randomly assigned animals after 5/6 nephrectomy to treatment with either saline (n=36) or 0.1 microg/kg body wt darbepoetin (n=24) subcutaneously once weekly. We monitored hematocrit, blood pressure, and serum creatinine regularly and obtained renal tissue 6 weeks after nephrectomy for morphological and immunohistochemical analysis. Darbepoetin-treated animals had significantly improved survival compared with saline-treated controls (63% versus 33%; P<0.05), although hematocrit levels were similar in both groups. Darbepoetin treatment ameliorated endothelial damage; attenuated the composite tissue injury score (saline 1.9+/-0.4; darbepoetin 0.4+/-0.2; P<0.001), which included vascular sclerosis, glomerulosclerosis, and tubulointerstitial damage; and preserved renal function. We found persistent activation of the pro-survival Akt signaling pathway in endothelial and epithelial glomerular cells in darbepoetin-treated animals, accompanied by a significant reduction of apoptotic cell death in renal tissue. CONCLUSIONS: Low-dose darbepoetin treatment confers vascular and tissue protection that is associated with persistent stimulation of the pro-survival Akt signaling pathway. The use of recombinant human erythropoietin or analogues may have utility in preventing ischemia-related progressive vascular injury and organ failure.

Uremia causes endothelial progenitor cell deficiency.

BACKGROUND: Circulating bone marrow-derived endothelial progenitor cells (EPCs) promote vascular repair. Their number in peripheral blood correlates with endothelial function and cardiovascular risk in humans. We explored whether uremia influences the number of EPCs. METHODS: We assessed circulating CD34+ hematopoietic progenitor cells in whole blood using flow cytometry and EPCs (in vitro assay) in 46 patients with advanced renal failure and in 46 age- and gender-matched healthy subjects. Further, the effect of uremia on EPC differentiation was studied in vitro and in vivo. RESULTS: Both in renal patients (r= 0.34, P < 0.02) and in healthy subjects (r= 0.32, P= 0.04) the number of EPCs was significantly correlated to the absolute number of CD34+ hematopoietic progenitor cells. Renal patients had significantly fewer EPCs than healthy subjects, however (167 +/- 15 cells/high power field vs. 235 +/- 17 cells/high power field; P < 0.05). Uremic serum significantly (P < 0.05) inhibited EPC differentiation and functional activity in vitro. Amelioration of uremia after institution of renal replacement therapy in patients with terminal renal failure also significantly (P < 0.05) increased the number of EPCs. CONCLUSION: Uremia inhibits differentiation of EPCs. This may impair cardiovascular repair mechanisms in patients with renal failure.