Prurigo nodularis and dialyzer membrane.

Prurigo nodularis is a skin disease with unknown origin which is frequent in patients on maintenance renal replacement therapy. Here, we report a patient who was dialyzed for more than 10 years with different dialyzers using different dialyzer membranes. Each time when the patient was switched to a polymethylmethacrylate membrane (Filtryzer BK-1.6P), itching and skin lesions disappeared completely. This effect could be verified three times.

Subtotal ablation of parietal epithelial cells induces crescent formation.

Parietal epithelial cells (PECs) of the renal glomerulus contribute to the formation of both cellular crescents in rapidly progressive GN and sclerotic lesions in FSGS. Subtotal transgenic ablation of podocytes induces FSGS but the effect of specific ablation of PECs is unknown. Here, we established an inducible transgenic mouse to allow subtotal ablation of PECs. Proteinuria developed during doxycycline-induced cellular ablation but fully reversed 26 days after termination of doxycycline administration. The ablation of PECs was focal, with only 30% of glomeruli exhibiting histologic changes; however, the number of PECs was reduced up to 90% within affected glomeruli. Ultrastructural analysis revealed disruption of PEC plasma membranes with cytoplasm shedding into Bowman's space. Podocytes showed focal foot process effacement, which was the most likely cause for transient proteinuria. After >9 days of cellular ablation, the remaining PECs formed cellular extensions to cover the denuded Bowman's capsule and expressed the activation marker CD44 de novo. The induced proliferation of PECs persisted throughout the observation period, resulting in the formation of typical cellular crescents with periglomerular infiltrate, albeit without accompanying proteinuria. In summary, subtotal ablation of PECs leads the remaining PECs to react with cellular activation and proliferation, which ultimately forms cellular crescents.

The HSP72 stress response of monocytes from patients on haemodialysis is impaired.

BACKGROUND: Induction of heat shock proteins (HSP), i.e. of the major family member HSP70, is an important cytoprotective-resistance mechanism for monocytes/ macrophages (Mphi). Patients on haemodialysis present with a high infectious morbidity and enhanced carcinoma incidence. Renal insufficiency-related alteration of microbicidal and tumoricidal functions of Mphi, major effectors of the immune system, might promote these diseases. METHODS: Freshly isolated Mphi from Sprague-Dawley rats 2 weeks after 5/6-nephrectomy and from patients on intermittent haemodialysis (IHD) were stimulated by heat shock (HS) and compared to stimulated Mphi of control rats or healthy volunteers (CTR). Expression of HSP72 (inducible HSP70) was assessed by RT-PCR, and/or flow cytometry. Apoptosis of Mphi was detected by flow cytometry (CD14/annexin V-labelling). RESULTS: In rat Mphi, baseline HSP72 expression was similar in both groups, but its induction was significantly impaired in renal insufficiency (214 +/- 68% less HSP70-mRNA versus CTR, n = 6). In patients, HSF-1-mRNA and HSP72-mRNA/protein response to HS was significantly lower, but not affected by dialysis session itself. In parallel, apoptosis of Mphi of patients was enhanced (+83 +/- 29% constitutive apoptotic Mphi versus CTR, n = 8), and HS-dependent protection from apoptosis with and without serum depletion (48 h depletion: HS, +275 +/- 37% apoptotic Mphi versus CTR, n = 6; full medium: +166 +/- 62% versus CTR, n = 8, P < 0.05) was inferior. CONCLUSIONS: Impaired HSP72 stress response of Mphi in patients on haemodialysis might contribute to the observed immune dysfunction and, therefore, to the increased susceptibility to infection and malignancy. Stress impairment is not restricted to uraemia but is already present in a rat model of chronic kidney disease.

Influence of heme oxygenase-1 on microcirculation after kidney transplantation.

BACKGROUND: Cytoprotective proteins, such as heme oxygenase-1 (HO-1), play a decisive role in ischemia-reperfusion injury during kidney transplantation. The aim of this study was to investigate the impact of heme oxygenase-1 on microcirculation and on ischemia-reperfusion injury in an isogenic kidney transplantation rat model. MATERIALS AND METHODS: Seventy male Lewis rats were distributed into three groups. In Group 1(control), the kidneys were only mobilized. In Groups 2 and 3, bilateral nephrectomy was performed, and a kidney from another Lewis rat was orthotopically transplanted on the left side. The donor animals in Group 3 received preconditioning with the HO-1 inductor hemin. 24 h after reperfusion graft function and morphology were examined. Microcirculation was investigated by in vivo microscopy of the renal surface 1 h after reperfusion. RESULTS: HO-1 preconditioning led to significantly lower serum creatinine and serum urea, as well as less histological damage and inducible nitric oxide synthase expression. Microcirculation was improved by a significant enlargement of the vascular diameter and an increase of the capillary flow. CONCLUSIONS: Treatment with hemin improves microcirculation by induction of HO-1 and reduces ischemia-reperfusion injury after kidney transplantation. HO-1 induction was shown to be a promising approach in the preconditioning of donor kidneys.

Stress associated proteins metallothionein, HO-1 and HSP 70 in human zero-hour biopsies of transplanted kidneys.

Light microscopic alterations reflecting both previous and preservation-induced changes in the donor organ are usually not very distinctive. The ischemia/reperfusion-associated injury depends primarily on the conditions of donor organ preservation. The present study examined human kidney biopsies with special attention paid to the molecular mechanisms of preservation-induced injury preceding reperfusion. Stress-associated proteins hemeoxygenase-1 (HO-1), heat shock protein 70 (HSP 70), and metallothionein (MT) were studied in human zero-hour biopsies of transplanted kidneys prior to reperfusion in 29 patients. Protein expression was evaluated by semiquantitative immunohistochemistry and Western blotting for HO-1 and HSP 70. These findings were correlated with terminal deoxynucleotidyltransferase-mediated 2'-deoxyuridine 5'-triphosphate-digoxigenin nick end labeling (TUNEL) staining and follow up. Compared to controls, MT and HSP 70 expression was significantly higher at zero hour. In contrast, HO-1 and the number of TUNEL-positive cells were not elevated. MT and HO-1 immunoexpression were inversely associated with graft function, and hence, were of prognostic relevance. MT and HSP 70 were sensitive to the duration of cold ischemia. MT and HO-1 are suitable indicators for tissue injury during ischemia and may serve as new predictive markers that need to be validated in further independent studies.

Protein kinase C (PKC) dependent induction of tissue factor (TF) by mesangial cells in response to inflammatory mediators and release during apoptosis.

1. In inflammatory kidney diseases procoagulatory activity (PCA) becomes evident. Glomerular fibrin deposits and capillary microthrombi are histopathological hallmarks in most forms of glomerulonephritis. 2. Therefore in this study the expression of tissue factor (TF) as the main inducer of thrombogenesis was examined in cultured human mesangial cells (MC) in response to proinflammatory stimuli such as interleukin-1 (IL-1 beta), tumour necrosis factor alpha (TNF-alpha) and lipopolysaccharide (LPS). Also main signalling pathways were investigated. 3. IL-1 beta, TNF-alpha and LPS induced TF in MC in a time and dose dependent manner on mRNA and protein levels. Highest activity was found after 12 h of stimulation. Induction of TF was completely blockable by BAPTA-AM, a chelator of intracellular [Ca(2+)](i) as well as calphostin, a protein kinase C (PKC) inhibitor. Activation of the protein kinase A (PKA) pathway had no influence on basal TF expression, but down-regulated cytokine-induced TF. The PKA blocker, KT5720, increased TF formation significantly. Since TF exerts its activity primarily on the surface of cells and after release of encrypted receptors we further tested TF activity in MC supernatants. IL-1 beta did not significantly increase TF activity in supernatants of intact cells. However, when MC were rendered apoptotic by oxidative metabolites, IL-1 beta treated MC released highly stimulated TF activity into the supernatants, suggesting that a paracrine activation of the coagulatory cascade can take place under such conditions. 4. Inflammatory mediators up-regulate TF expression in MC by a PKC dependent pathway whereas PKA can serve as a negative feed-back link. Apoptosis of inflammatory MC may trigger to spread PCA.

Acute renal failure in IgA nephropathy: aggravation by gross hematuria due to anticoagulant treatment.

IgA nephropathy is one of the most common forms of glomerulonephritis. Macroscopic or microscopic hematuria with mild proteinuria are the main symptoms. Without complicating factors, IgA nephropathy has a favourable long-term prognosis. We report a case of reversible acute renal failure (ARF) as a complication of mild IgA nephropathy while oral anticoagulants were administered. Diagnosis was based on a renal biopsy showing marked granular mesangial IgA-deposition. In addition, numerous tubules were extended and completely obstructed by red blood cell casts. After hemodialysis treatment and parallel anti-inflammatory steroids and after stopping anticoagulation, renal function gradually improved up to complete remission. This report indicates that anticoagulatory treatment may have negative effects on the long-term prognosis of IgA nephropathy with respect to development of ARF or tubulo-interstitial inflammation.

Monthly administration of a continuous erythropoietin receptor activator provides efficient haemoglobin control in non-dialysis patients during routine clinical practice: results from the non-interventional, single-cohort, multicentre, SUPRA study.

BACKGROUND: The continuous erythropoietin receptor activator (C.E.R.A.) has a long half-life, a relatively low binding affinity for the erythropoiesis receptor and low systemic clearance. These characteristics permit once-monthly dosing, which could reduce staffing requirements and be advantageous for patients. However, outcomes observed during controlled trials of C.E.R.A. have not been assessed under everyday clinical conditions in which physicians make all therapeutic decisions based on their own experience, rather than according to a pre-defined protocol. OBJECTIVE: This study aimed to assess whether the efficacy and safety of C.E.R.A. reported during controlled trials are reproducible under routine clinical conditions. METHODS: This was a non-interventional, single-cohort, multicentre study carried out in 92 specialist nephrology clinics and private practices in Germany. The study included patients with non-dialysis chronic kidney disease and anaemia, with or without current erythropoiesis stimulating agent (ESA) therapy. C.E.R.A. initiation and dosing was at the discretion of the physician. The primary efficacy variable was the proportion of patients for whom all measured haemoglobin (Hb) values during months 7-9 were within the range 11-12 g/dL ('responders'). RESULTS: 335 patients received ≥1 dose of C.E.R.A.; 150 had previously received ESA therapy. The mean number of doses was 7.6 per patient over a mean follow-up of 7.9 months. Mean ± SD Hb was 10.7 ± 1.1 g/dL at baseline and 11.3 ± 1.1 g/dL at the final visit (efficacy population, n = 205). The primary endpoint, all measured Hb values during months 7-9 within the range 11-12 g/dL, was achieved by 19.0% (39/205) of patients, increasing to 41.5% for Hb 11-13 g/dL, 42.0% for 10-12 g/dL and 76.6% for Hb ≥10 g/dL. Hb fluctuation during months 7-9 was ≤1 g/dL in 185/205 patients (90.2%). C.E.R.A. was well tolerated without novel safety concerns. CONCLUSION: Hb levels remained stable during routine use of C.E.R.A. in an unselected population of non-dialysis chronic kidney disease patients with anaemia. C.E.R.A. was administered approximately monthly compared with 3-7 doses per month on previous ESA therapy.

Heme-induced heme oxygenase-1 (HO-1) in human monocytes inhibits apoptosis despite caspase-3 up-regulation.

Monocyte activation, apoptosis and differentiation are hallmarks of most inflammatory vascular disorders. We studied the effects of heme oxygenase-1 (HO-1) induced by its substrate hemin on apoptosis, caspase-3 expression and the differentiation of freshly isolated human monocytes. Hemin induced HO-1 in a dose- and time-dependent fashion as measured by semi-quantitative RT-PCR and flow cytometry. Apoptosis was markedly suppressed by hemin in cells rendered apoptotic by serum deprivation or dexamethasone as determined by flow cytometric detection of annexin V binding or transmission electron microscopy (TEM). The specific HO-1 inhibitor zinc protoporphyrin (ZnPP) reversed the effects of hemin on monocyte apoptosis and diminished cell lifespan. Surprisingly, the cytoprotective effects of hemin were positively correlated with caspase-3 up-regulation. Hemin-induced apoptosis suppression was enhanced by the caspase-3 inhibitor DEVD-CHO, indicating that caspase-3 was active in a pro-apoptotic fashion. Hemin inhibited CD95 as a putative cytoprotective mechanism. Morphological studies and detection of CD86 showed that monocytes differentiated into macrophages in response to hemin after relatively long incubation times, a phenomenon that might be provoked by caspase-3-regulated pathways. Our results confirm a similar cytoprotective effect of hemin/HO-1 for monocytes as has been shown for other cells, despite caspase-3 up-regulation. The fact that HO-1 may adversely affect monocyte survival and differentiation could be of particular significance in future therapies for occlusive vascular diseases or transplant rejection.

Long-term follow-up of double kidney transplantation using a score for evaluation of marginal donors*.

To face the problem of organ shortage, marginal grafts from 36 donors which had been refused for single transplantation were used for double-kidney transplantation (D-KTX). The residual kidney function was evaluated by the Muenster double kidney score. In a 5-year period kidneys from 57 marginal donors were transferred to our center. According to the Muenster double kidney score, the kidneys were distributed to single, double or refusal of transplantation. Sixteen male and 20 female donors were used for D-KTX (70+/-9.3 years, range 53-86). Thirty-six recipients (23 male, 13 female; 60.5+/-6.9 years) were double-grafted within a mean cold ischemic time of 19.3+/-3.4 h. Immunosuppression varied according to human leukocyte antigen (HLA)-mismatch. Graft and patient survival was observed up to 5 years. Initial graft function rate was 69%. Two recipients had a primary nonfunction (5.5%) and nine recipients suffered from delayed graft function (DGF; 25%). One-, 2-, 3-year creatinine values were 1.6 +/- 0.5, 1.9 +/- 0.6 and 2.2 +/- 0.7 mg/dl, respectively. One-, 2-, 3-, 4- and 5-year function rate was 93.7%, 93.5%, 81.8%, 76.4% and 55%, respectively (n = 32, 31, 22, 17 and 9). Acute rejection rate was 19%. 4 grafts were lost to chronic rejection (months 22, 25, 28, 48). Six (16%) died in long-term follow-up because of pneumonia (n = 2), carcinoma of the lung (n = 1), cardial complications (n = 2) and multiorgan failure (n = 1). D-KTX is a safe way to face the problem of organ shortage. However, a score for preoperative evaluation of marginal kidneys for single, dual or refusal of transplantation is essential.

Down-regulation of monocyte apoptosis by phagocytosis of platelets: involvement of a caspase-9, caspase-3, and heat shock protein 70-dependent pathway.

Monocytes interact and cross-talk with platelets in many settings including inflammation, hemostasis, or vascular disorders. During inflammatory diseases, there is a rapid targeting of monocytes and platelets to points of inflammation and endothelial injury, where they lie side-by-side. In this in vitro study, we investigated different interactions between monocytes and platelets and elucidated whether platelets might affect monocyte apoptosis. Freshly isolated human monocytes were rendered apoptotic by serum deprivation or CD95 ligation and cocultured with platelets. Monocyte apoptosis was determined by flow cytometry, TUNEL staining, DNA electrophoresis, and transmission electron microscopy imaging. We could show that monocyte apoptosis was highly suppressed when platelets were added to the cultures. Transmission electron microscopy depicted that monocytes completely ingested thrombocytes by phagocytosis. Blocking thrombocyte uptake by the phagocytosis inhibitor cytochalasin D abrogated the enhanced monocyte survival and led to high apoptosis levels. Monocyte survival was paralleled by down-regulation of caspase-9 and -3 and up-regulation of heat shock protein 70 during uptake of platelets. Platelet supernatants and contents of platelet granules were ineffective in altering monocyte senescence. Also, ingestion of latex beads or zymosan by monocytes was ineffective to mimic platelet-dependent rescue from apoptosis. In conclusion, this study shows that platelets can suppress apoptosis of monocytes by a specific phagocytosis-dependent process with further consequences for atherosclerotic or inflammatory conditions.

Outcome of kidney transplantation in patients with inherited thrombophilia: data of a prospective study.

Inherited prothrombotic risk factors predispose patients to thromboembolic events. In kidney transplant recipients, thrombophilia may manifest itself with venous thrombosis, microvascular occlusion, or acute rejection with major consequences for allograft survival. This is a prospective study on 165 renal allograft recipients to evaluate the contribution of genetic thrombophilic risk factors to transplant outcome. Besides antithrombin, protein C, and protein S deficiencies, none of which was found in our patient group, factor V G1691A (FV G1691A), prothrombin G20210A (PT G20210A) mutations, and methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphisms were studied. The primary endpoint of the study was occurrence of an acute rejection within the first 90 d and transplant loss within 1 yr. Heterozygous FV G1691A and PT G20210A mutations and the MTHFR T677T variant were significantly associated with acute rejections with rejection rates of 68%, 67%, and 71%, respectively, as compared with 35% in patients not carrying these genotypes. Many rejections that were histologically proven were acute vascular ones. Transplant loss was significantly associated exclusively with the PT G20210A group (50% 1-yr graft survival; odds ratio, 10.0; 95% confidence interval, 1.8 to 56.1). PT G20210A patients exerted the highest prothrombotic activity pretransplant, as determined by prothrombin 1.2 fragments (PT F1.2), which may be the background for minor outcome. In conclusion, common prothrombotic mutations are significantly associated with acute rejections, especially vascular rejections, and for PT G20210A also with early transplant failure. Screening for hypercoagulable states pretransplant is recommended to intensify anticoagulatory treatment posttransplant.