Atypical hemolytic uremic syndrome in the era of terminal complement inhibition: an observational cohort study.

Historically, the majority of patients with complement-mediated atypical hemolytic uremic syndrome (CaHUS) progress to end-stage kidney disease (ESKD). Single-arm trials of eculizumab with a short follow-up suggested efficacy. We prove, for the first time to our knowledge, in a genotype matched CaHUS cohort that the 5-year cumulative estimate of ESKD-free survival improved from 39.5% in a control cohort to 85.5% in the eculizumab-treated cohort (hazard ratio, 4.95; 95% confidence interval [CI], 2.75-8.90; P = .000; number needed to treat, 2.17 [95% CI, 1.81-2.73]). The outcome of eculizumab treatment is associated with the underlying genotype. Lower serum creatinine, lower platelet count, lower blood pressure, and younger age at presentation as well as shorter time between presentation and the first dose of eculizumab were associated with estimated glomerular filtration rate >60 ml/min at 6 months in multivariate analysis. The rate of meningococcal infection in the treated cohort was 550 times greater than the background rate in the general population. The relapse rate upon eculizumab withdrawal was 1 per 9.5 person years for patients with a pathogenic mutation and 1 per 10.8 person years for those with a variant of uncertain significance. No relapses were recorded in 67.3 person years off eculizumab in those with no rare genetic variants. Eculizumab was restarted in 6 individuals with functioning kidneys in whom it had been stopped, with no individual progressing to ESKD. We demonstrated that biallelic pathogenic mutations in RNA-processing genes, including EXOSC3, encoding an essential part of the RNA exosome, cause eculizumab nonresponsive aHUS. Recessive HSD11B2 mutations causing apparent mineralocorticoid excess may also present with thrombotic microangiopathy.

Nitration of chemokine CXCL8 acts as a natural mechanism to limit acute inflammation.

Chemokine CXCL8 is a key facilitator of the human host immune response, mediating neutrophil migration, and activation at the site of infection and injury. The oxidative burst is an important effector mechanism which leads to the generation of reactive nitrogen species (RNS), including peroxynitrite. The current study was performed to determine the potential for nitration to alter the biological properties of CXCL8 and its detection in human disease. Here, we show peroxynitrite nitrates CXCL8 and thereby regulates neutrophil migration and activation. The nitrated chemokine was unable to induce transendothelial neutrophil migration in vitro and failed to promote leukocyte recruitment in vivo. This reduced activity is due to impairment in both G protein-coupled receptor signaling and glycosaminoglycan binding. Using a novel antibody, nitrated CXCL8 was detected in bronchoalveolar lavage samples from patients with pneumonia. These findings were validated by mass spectrometry. Our results provide the first direct evidence of chemokine nitration in human pathophysiology and suggest a natural mechanism that limits acute inflammation.

Dissecting the Therapeutic Mechanisms of Sphingosine-1-Phosphate Receptor Agonism during Ischaemia and Reperfusion.

Sphingosine 1-phosphate (S1P) and S1P receptors (S1PR) regulate many cellular processes, including lymphocyte migration and endothelial barrier function. As neutrophils are major mediators of inflammation, their transendothelial migration may be the target of therapeutic approaches to inflammatory conditions such as ischaemia-reperfusion injury (IRI). The aim of this project was to assess whether these therapeutic effects are mediated by S1P acting on neutrophils directly or indirectly through the endothelial cells. First, our murine model of peritoneum cell recruitment demonstrated the ability of S1P to reduce CXCL8-mediated neutrophil recruitment. Mechanistic in vitro studies revealed that S1P signals in neutrophils mainly through the S1PR1 and 4 receptors and induces phosphorylation of ERK1/2; however, this had no effect on neutrophil transmigration and adhesion. S1P treatment of endothelial cells significantly reduced TNF-α-induced neutrophil adhesion under flow (p < 0.01) and transendothelial migration towards CXCL8 during in vitro chemotaxis assays (p < 0.05). S1PR1 agonist CYM5442 treatment of endothelial cells also reduced neutrophil transmigration (p < 0.01) and endothelial permeability (p < 0.005), as shown using in vitro permeability assays. S1PR3 agonist had no effects on chemotaxis or permeability. In an in vivo mouse model of renal IRI, S1PR agonism with CYM5442 reduced endothelial permeability as shown by reduced Evan's Blue dye extravasation. Western blot was used to assess phosphorylation at different sites on vascular endothelial (VE)-cadherin and showed that CYM5442 reduced VEGF-mediated phosphorylation. Taken together, the results of this study suggest that reductions in neutrophil infiltration during IRI in response to S1P are mediated primarily by S1PR1 signalling on endothelial cells, possibly by altering phosphorylation of VE-cadherin. The results also demonstrate the therapeutic potential of S1PR1 agonist during IRI.

MicroRNA antagonist therapy during normothermic machine perfusion of donor kidneys.

Normothermic machine perfusion (NMP) is a novel clinical approach to overcome the limitations of traditional hypothermic organ preservation. NMP can be used to assess and recondition organs prior to transplant and is the subject of clinical trials in solid organ transplantation. In addition, NMP provides an opportunity to deliver therapeutic agents directly to the organ, thus avoiding many limitations associated with systemic treatment of the recipient. We report the delivery of oligonucleotide-based therapy to human kidneys during NMP, in this case to target microRNA function (antagomir). An antagomir targeting mir-24-3p localized to the endothelium and proximal tubular epithelium. Endosomal uptake during NMP conditions facilitated antagomir co-localization with proteins involved in the RNA-induced silencing complex (RISC) and demonstrated engagement of the miRNA target. This pattern of uptake was not seen during cold perfusion. Targeting mir-24-3p action increased expression of genes controlled by this microRNA, including heme oxygenase-1 and sphingosine-1-phosphate receptor 1. The expression of genes not under the control of mir-24-3p was unchanged, indicating specificity of the antagomir effect. In summary, this is the first report of ex vivo gymnotic delivery of oligonucleotide to the human kidney and demonstrates that NMP provides the platform to bind and block detrimental microRNAs in donor kidneys prior to transplantation.

Comparative efficacy of ravulizumab and eculizumab in the treatment of atypical hemolytic uremic syndrome: An indirect comparison using clinical trial data.

Ravulizumab and eculizumab are approved terminal complement inhibitor treatments for atypical hemolytic uremic syndrome (aHUS). Ravulizumab was engineered from eculizumab to have an increased half-life allowing for reduced dosing frequency (8-weekly vs. 2-weekly). To account for differences in respective clinical trials, a validated balancing technique was used to enable an indirect comparison of ravulizumab and eculizumab treatment efficacy in aHUS. Patient-level data from four eculizumab clinical trials were available for pooling and comparison with data from two ravulizumab trials. In the primary analysis, adult native kidney data were compared. Propensity scores were calculated from baseline characteristics (dialysis status, estimated glomerular filtration rate, platelet count, serum lactate dehydrogenase). Stabilized inverse probability weighting was used to balance groups. Changes in outcomes from baseline to 26 weeks were compared between treatment groups. Sensitivity and subgroup analyses were conducted to assess the robustness of findings. Overall, 85 patients (46 ravulizumab, 39 eculizumab) were included in the primary analysis. Demographic and clinical characteristics were well balanced after weighting at baseline. At 26 weeks, clinical outcomes (including renal function, hematological markers, and dialysis prevalence), and fatigue and quality of life measures were improved with eculizumab and ravulizumab treatment. No differences between treatment groups reached statistical significance, although confidence intervals were wide. Sensitivity and subgroup analysis results were consistent with those of the primary analysis. Using appropriate methodology for indirect comparison of studies, no differences in outcomes were seen between ravulizumab and eculizumab, although, owing to small sample sizes, confidence intervals were wide.

Novel delivery of cellular therapy to reduce ischemia reperfusion injury in kidney transplantation.

Ex vivo normothermic machine perfusion (NMP) of donor kidneys prior to transplantation provides a platform for direct delivery of cellular therapeutics to optimize organ quality prior to transplantation. Multipotent Adult Progenitor Cells (MAPC® ) possess potent immunomodulatory properties that could minimize ischemia reperfusion injury. We investigated the potential capability of MAPC cells in kidney NMP. Pairs (5) of human kidneys, from the same donor, were simultaneously perfused for 7 hours. Kidneys were randomly allocated to receive MAPC treatment or control. Serial samples of perfusate, urine, and tissue biopsies were taken for comparison. MAPC-treated kidneys demonstrated improved urine output (P = .009), decreased expression of injury biomarker NGAL (P = .012), improved microvascular perfusion on contrast-enhanced ultrasound (cortex P = .019, medulla P = .001), downregulation of interleukin (IL)-1ß (P = .050), and upregulation of IL-10 (P < .047) and Indolamine-2, 3-dioxygenase (P = .050). A chemotaxis model demonstrated decreased neutrophil recruitment when stimulated with perfusate from MAPC-treated kidneys (P < .001). Immunofluorescence revealed prelabeled MAPC cells in the perivascular space of kidneys during NMP. We report the first successful delivery of cellular therapy to a human kidney during NMP. Kidneys treated with MAPC cells demonstrate improvement in clinically relevant parameters and injury biomarkers. This novel method of cell therapy delivery provides an exciting opportunity to recondition organs prior to transplantation.

Cell therapy during machine perfusion.

There has been increasing use of organs from extended criteria or donation after circulatory death donors to meet the demands of the transplant waiting list. Over the past decade, there has been considerable progress in technologies to preserve organs prior to transplantation to improve the function of these marginal organs. This has led to the development of normothermic machine perfusion, whereby an organ is perfused with warmed, oxygenated blood and nutrients to resume normal physiological function in an isolated ex-vivo platform. With this advance in preservation comes significant opportunities to recondition, repair and regenerate organs prior to transplantation using cellular therapies. This review aims to discuss the possibilities of machine perfusion technology; highlighting the potential for organ-directed reconditioning and the future avenues for investigation in this field.

MiR-126-3p Is Dynamically Regulated in Endothelial-to-Mesenchymal Transition during Fibrosis.

In fibrotic diseases, myofibroblasts derive from a range of cell types including endothelial-to-mesenchymal transition (EndMT). Increasing evidence suggests that miRNAs are key regulators in biological processes but their profile is relatively understudied in EndMT. In human umbilical vein endothelial cells (HUVEC), EndMT was induced by treatment with TGFß2 and IL1ß. A significant decrease in endothelial markers such as VE-cadherin, CD31 and an increase in mesenchymal markers such as fibronectin were observed. In parallel, miRNA profiling showed that miR-126-3p was down-regulated in HUVECs undergoing EndMT and over-expression of miR-126-3p prevented EndMT, maintaining CD31 and repressing fibronectin expression. EndMT was investigated using lineage tracing with transgenic Cdh5-Cre-ERT2; Rosa26R-stop-YFP mice in two established models of fibrosis: cardiac ischaemic injury and kidney ureteric occlusion. In both cardiac and kidney fibrosis, lineage tracing showed a significant subpopulation of endothelial-derived cells expressed mesenchymal markers, indicating they had undergone EndMT. In addition, miR-126-3p was restricted to endothelial cells and down-regulated in murine fibrotic kidney and heart tissue. These findings were confirmed in patient kidney biopsies. MiR-126-3p expression is restricted to endothelial cells and is down-regulated during EndMT. Over-expression of miR-126-3p reduces EndMT, therefore, it could be considered for miRNA-based therapeutics in fibrotic organs.

Long-term outcomes and response to treatment in diacylglycerol kinase epsilon nephropathy.

Recessive mutations in diacylglycerol kinase epsilon (DGKE) display genetic pleiotropy, with pathological features reported as either thrombotic microangiopathy or membranoproliferative glomerulonephritis (MPGN), and clinical features of atypical hemolytic uremic syndrome (aHUS), nephrotic syndrome or both. Pathophysiological mechanisms and optimal management strategies have not yet been defined. In prospective and retrospective studies of aHUS referred to the United Kingdom National aHUS service and prospective studies of MPGN referred to the National Registry of Rare Kidney Diseases for MPGN we defined the incidence of DGKE aHUS as 0.009/million/year and so-called DGKE MPGN as 0.006/million/year, giving a combined incidence of 0.015/million/year. Here, we describe a cohort of sixteen individuals with DGKE nephropathy. One presented with isolated nephrotic syndrome. Analysis of pathological features reveals that DGKE mutations give an MPGN-like appearance to different extents, with but more often without changes in arterioles or arteries. In 15 patients presenting with aHUS, ten had concurrent substantial proteinuria. Identified triggering events were rare but coexistent developmental disorders were seen in six. Nine with aHUS experienced at least one relapse, although in only one did a relapse of aHUS occur after age five years. Persistent proteinuria was seen in the majority of cases. Only two individuals have reached end stage renal disease, 20 years after the initial presentation, and in one, renal transplantation was successfully undertaken without relapse. Six individuals received eculizumab. Relapses on treatment occurred in one individual. In four individuals eculizumab was withdrawn, with one spontaneously resolving aHUS relapse occurring. Thus we suggest that DGKE-mediated aHUS is eculizumab non-responsive and that in individuals who currently receive eculizumab therapy it can be safely withdrawn. This has important patient safety and economic implications.

The methyltransferase SET9 regulates TGFB1 activation of renal fibroblasts via interaction with SMAD3.

Chronic kidney disease (CKD) is a global socioeconomic problem. It is characterised by the presence of differentiated myofibroblasts, which cause tissue fibrosis in response to TGFB1, leading to renal failure. Here, we define a novel interaction between the SET9 lysine methyltransferase (also known as SETD7) and SMAD3, the principal mediator of TGFB1 signalling in myofibroblasts. We show that SET9-deficient fibroblasts exhibit globally altered gene expression profiles in response to TGFB1, whilst overexpression of SET9 enhances SMAD3 transcriptional activity. We also show that SET9 facilitates nuclear import of SMAD3 and controls SMAD3 protein degradation via ubiquitylation. On a cellular level, we demonstrate that SET9 is broadly required for the effects of TGFB1 in diseased primary renal fibroblasts; SET9 promotes fibroblast migration into wounds, expression of extracellular matrix proteins, collagen contractility and myofibroblast differentiation. Finally, we demonstrate that SET9 is recruited to the α-smooth muscle actin gene in response to TGFB1, providing a mechanism by which SET9 regulates myofibroblast contractility and differentiation. Together with previous studies, we make the case for SET9 inhibition in the treatment of progressive CKD.

The impact of severe acute kidney injury requiring renal replacement therapy on survival and renal function of heart transplant recipients - a UK cohort study.

Severe acute kidney injury (AKI), defined as requiring renal replacement therapy (RRT), is associated with higher mortality postheart transplantation, but its long-term renal consequences are not known. Anonymized data of 3365 patients, who underwent heart transplantation between 1995 and 2017, were retrieved from the UK Transplant Registry. Multivariable binary logistic regression was performed to identify risk factors for severe AKI requiring RRT, Kaplan-Meier analysis to compare survival and renal function deterioration of the RRT and non-RRT groups, and multivariable Cox regression model to identify predicting factors of mortality and end-stage renal disease (ESRD). 26.0% of heart recipients received RRT post-transplant. The RRT group has lower survival rates at all time points, especially in the immediate post-transplant period. However, conditional on 3 months survival, older age, diabetes and coronary heart disease, but not post-transplant RRT, were the risk factors for long-term survival. The predicting factors for ESRD were insulin-dependent diabetes, renal function at transplantation, eGFR decline in the first 3 months post-transplant, post-transplant severe AKI and transplantation era. Severe AKI requiring RRT post-transplant is associated with worse short-term survival, but has no impact on long-term mortality. It also accelerates recipients' renal function deterioration in the long term.

Immunosuppression-induced clonal T-cell lymphoproliferative disease causing severe diarrhoea mimicking coeliac disease following renal transplantation: a case report.

BACKGROUND: Post-transplant lymphoproliferative disease is a recognized complication following solid organ transplantation. This is usually a B cell disease and frequently associated with Epstein Barr virus infection, although T cell PTLD can occur. T cell PTLD is usually a monomorphic, lymphomatous disease associated with an adverse prognosis. CASE REPORT: We report a 52 year old male pre-emptive renal transplant recipient who developed severe diarrhea with weight loss following intensification of his immunosuppression due to antibody mediated rejection 3 years after transplantation. Duodenal biopsy demonstrated monoclonal CD8+ T cell duodenitis leading to increased intraepithlieal lymphocytes and sub-total villous atrophy mimicking coeliac disease. Coeliac disease was excluded by negative anti-tissue transglutaminase antibody, HLA-DQ2 and HLA-DQ8 testing. There was no evidence of lymphoma either on biopsy or CT enterography and no FDG avid disease on PET. Symptoms did not improve with reduction of immunosuppression, but resolved fully on complete withdrawal of treatment. The transplant failed and he was established on dialysis. The diagnosis was early PTLD. CONCLUSIONS: Oesophagogastroduodenoscopy with small bowel biopsies is a useful investigation for determining the cause of diarrhoea in renal transplant patients when more common causes have been excluded. This is the first report that we are aware of clonal T cell PTLD mimicking coeliac disease which only resolved after complete withdrawal of immunosuppression. As treatments for lymphoma are aggressive they are only initiated in the malignant phase and management of early stage PTLD is to minimise risk of progression by reducing immunosuppression. Any plans to retransplant will have to take into consideration the possibility that PTLD will recur.

Mutations in mitochondrial DNA causing tubulointerstitial kidney disease.

Tubulointerstitial kidney disease is an important cause of progressive renal failure whose aetiology is incompletely understood. We analysed a large pedigree with maternally inherited tubulointerstitial kidney disease and identified a homoplasmic substitution in the control region of the mitochondrial genome (m.547A>T). While mutations in mtDNA coding sequence are a well recognised cause of disease affecting multiple organs, mutations in the control region have never been shown to cause disease. Strikingly, our patients did not have classical features of mitochondrial disease. Patient fibroblasts showed reduced levels of mitochondrial tRNAPhe, tRNALeu1 and reduced mitochondrial protein translation and respiration. Mitochondrial transfer demonstrated mitochondrial transmission of the defect and in vitro assays showed reduced activity of the heavy strand promoter. We also identified further kindreds with the same phenotype carrying a homoplasmic mutation in mitochondrial tRNAPhe (m.616T>C). Thus mutations in mitochondrial DNA can cause maternally inherited renal disease, likely mediated through reduced function of mitochondrial tRNAPhe.

A C-terminal CXCL8 peptide based on chemokine-glycosaminoglycan interactions reduces neutrophil adhesion and migration during inflammation.

Leucocyte recruitment is critical during many acute and chronic inflammatory diseases. Chemokines are key mediators of leucocyte recruitment during the inflammatory response, by signalling through specific chemokine G-protein-coupled receptors (GPCRs). In addition, chemokines interact with cell-surface glycosaminoglycans (GAGs) to generate a chemotactic gradient. The chemokine interleukin-8/CXCL8, a prototypical neutrophil chemoattractant, is characterized by a long, highly positively charged GAG-binding C-terminal region, absent in most other chemokines. To examine whether the CXCL8 C-terminal peptide has a modulatory role in GAG binding during neutrophil recruitment, we synthesized the wild-type CXCL8 C-terminal [CXCL8 (54-72)] (Peptide 1), a peptide with a substitution of glutamic acid (E) 70 with lysine (K) (Peptide 2) to increase positive charge; and also, a scrambled sequence peptide (Peptide 3). Surface plasmon resonance showed that Peptide 1, corresponding to the core CXCL8 GAG-binding region, binds to GAG but Peptide 2 binding was detected at lower concentrations. In the absence of cellular GAG, the peptides did not affect CXCL8-induced calcium signalling or neutrophil chemotaxis along a diffusion gradient, suggesting no effect on GPCR binding. All peptides equally inhibited neutrophil adhesion to endothelial cells under physiological flow conditions. Peptide 2, with its greater positive charge and binding to polyanionic GAG, inhibited CXCL8-induced neutrophil transendothelial migration. Our studies suggest that the E70K CXCL8 peptide, may serve as a lead molecule for further development of therapeutic inhibitors of neutrophil-mediated inflammation based on modulation of chemokine-GAG binding.

Ischaemia reperfusion injury: mechanisms of progression to chronic graft dysfunction.

The increasing use of extended criteria organs to meet the demand for kidney transplantation raises an important question of how the severity of early ischaemic injury influences long-term outcomes. Significant acute ischaemic kidney injury is associated with delayed graft function, increased immune-associated events and, ultimately, earlier deterioration of graft function. A comprehensive understanding of immediate molecular events that ensue post-ischaemia and their potential long-term consequences are key to the discovery of novel therapeutic targets. Acute ischaemic injury primarily affects tubular structure and function. Depending on the severity and persistence of the insult, this may resolve completely, leading to restoration of normal function, or be sustained, resulting in persistent renal impairment and progressive functional loss. Long-term effects of acute renal ischaemia are mediated by several mechanisms including hypoxia, HIF-1 activation, endothelial dysfunction leading to vascular rarefaction, sustained pro-inflammatory stimuli involving innate and adaptive immune responses, failure of tubular cells to recover and epigenetic changes. This review describes the biological relevance and interaction of these mechanisms based on currently available evidence.

Outcomes in patients with atypical hemolytic uremic syndrome treated with eculizumab in a long-term observational study.

BACKGROUND: There are limited long-term outcome data in eculizumab-treated patients with atypical hemolytic uremic syndrome (aHUS). We report final results from the largest prospective, observational, multicenter study of patients with aHUS treated with eculizumab. METHODS: Patients with aHUS who participated in any of five parent eculizumab trials and received at least one eculizumab infusion were eligible for enrollment in a long-term follow-up study. Rates of thrombotic microangiopathy (TMA) manifestations off versus on eculizumab were evaluated. Additional endpoints included change from baseline estimated glomerular filtration rate (eGFR), long-term renal outcomes, and serious targeted treatment-emergent adverse events. RESULTS: Among 93 patients (0-80 years of age), 51 (55%) remained on eculizumab and 42 (45%) discontinued; for those who discontinued, 21 (50%) reinitiated therapy. Patients who reinitiated eculizumab had similar baseline clinical characteristics to patients who remained on eculizumab, with higher likelihood of genetic/autoimmune complement abnormalities, more prior TMAs, and longer disease course versus those who did not reinitiate. Mean eGFR improved rapidly and remained stable for up to 6 years on eculizumab. In patients who discontinued, there was a trend toward decreasing renal function over time from discontinuation. Additionally, off-treatment TMA manifestation rates were higher in those aged < 18 years at diagnosis, with identified genetic/autoimmune complement abnormalities, or history of multiple TMAs prior to eculizumab initiation. The safety profile was consistent with previous studies. Three definite and one possible meningococcal infections related to eculizumab were reported and resolved with treatment. Three deaths unrelated to eculizumab were reported. CONCLUSIONS: The current study confirms the efficacy and safety of eculizumab in aHUS, particularly with regard to long-term renal function and TMA events. Pediatric age at disease onset and presence of genetic or autoimmune complement abnormalities are risk factors for TMA events off treatment. Overall, patients who discontinue eculizumab may be at risk for additional TMA manifestations and renal function decreases. Discontinuation of eculizumab, with careful monitoring, is an option in select patients with consideration of patient preference, organ function normalization, and risk factors for relapse, including mutational analysis, age of onset, and history of multiple TMA episodes. TRIAL REGISTRATION: ClinicalTrials.gov NCT01522170 , January 31, 2012.

Factor H autoantibody is associated with atypical hemolytic uremic syndrome in children in the United Kingdom and Ireland.

Factor H autoantibodies can impair complement regulation, resulting in atypical hemolytic uremic syndrome, predominantly in childhood. There are no trials investigating treatment, and clinical practice is only informed by retrospective cohort analysis. Here we examined 175 children presenting with atypical hemolytic uremic syndrome in the United Kingdom and Ireland for factor H autoantibodies that included 17 children with titers above the international standard. Of the 17, seven had a concomitant rare genetic variant in a gene encoding a complement pathway component or regulator. Two children received supportive treatment; both developed established renal failure. Plasma exchange was associated with a poor rate of renal recovery in seven of 11 treated. Six patients treated with eculizumab recovered renal function. Contrary to global practice, immunosuppressive therapy to prevent relapse in plasma exchange-treated patients was not adopted due to concerns over treatment-associated complications. Without immunosuppression, the relapse rate was high (five of seven). However, reintroduction of treatment resulted in recovery of renal function. All patients treated with eculizumab achieved sustained remission. Five patients received renal transplants without specific factor H autoantibody-targeted treatment with recurrence in one who also had a functionally significant CFI mutation. Thus, our current practice is to initiate eculizumab therapy for treatment of factor H autoantibody-mediated atypical hemolytic uremic syndrome rather than plasma exchange with or without immunosuppression. Based on this retrospective analysis we see no suggestion of inferior treatment, albeit the strength of our conclusions is limited by the small sample size.

Outcomes of patients with atypical haemolytic uraemic syndrome with native and transplanted kidneys treated with eculizumab: a pooled post hoc analysis.

Atypical haemolytic uraemic syndrome (aHUS) often leads to end-stage renal disease (ESRD) and kidney transplantation; graft loss rates are high due to disease recurrence. A post hoc analysis of four prospective clinical trials in aHUS was performed to evaluate eculizumab, a terminal complement inhibitor, in patients with native or transplanted kidneys. The trials included 26-week treatment and extension periods. Dialysis, transplant and graft loss were evaluated. Study endpoints included complete thrombotic microangiopathy (TMA) response, TMA event-free status, haematologic and renal parameters and adverse events. Of 100 patients, 74 had native kidneys and 26 in the transplant subgroup had a collective history of 38 grafts. No patients lost grafts and only one with pre-existing ESRD received a transplant on treatment. Efficacy endpoints were achieved similarly in both subgroups. After 26 weeks, mean absolute estimated glomerular filtration rate increased from baseline to 61 and 37 ml/min/1.73 m2 in native (n = 71; P < 0.0001) and transplanted kidney (n = 25; P = 0.0092) subgroups. Two patients (one/subgroup) developed meningococcal infections; both recovered, one continued therapy. Eculizumab was well tolerated. Eculizumab improved haematologic and renal outcomes in both subgroups. In patients with histories of multiple graft losses, eculizumab protected kidney function.

Regulation of Chemokine Function: The Roles of GAG-Binding and Post-Translational Nitration.

The primary function of chemokines is to direct the migration of leukocytes to the site of injury during inflammation. The effects of chemokines are modulated by several means, including binding to G-protein coupled receptors (GPCRs), binding to glycosaminoglycans (GAGs), and through post-translational modifications (PTMs). GAGs, present on cell surfaces, bind chemokines released in response to injury. Chemokines bind leukocytes via their GPCRs, which directs migration and contributes to local inflammation. Studies have shown that GAGs or GAG-binding peptides can be used to interfere with chemokine binding and reduce leukocyte recruitment. Post-translational modifications of chemokines, such as nitration, which occurs due to the production of reactive species during oxidative stress, can also alter their biological activity. This review describes the regulation of chemokine function by GAG-binding ability and by post-translational nitration. These are both aspects of chemokine biology that could be targeted if the therapeutic potential of chemokines, like CXCL8, to modulate inflammation is to be realised.

An extended mini-complement factor H molecule ameliorates experimental C3 glomerulopathy.

Abnormal regulation of the complement alternative pathway is associated with C3 glomerulopathy. Complement factor H is the main plasma regulator of the alternative pathway and consists of 20 short consensus repeat (SCR) domains. Although recombinant full-length factor H represents a logical treatment for C3 glomerulopathy, its production has proved challenging. We and others have designed recombinant mini-factor H proteins in which 'non-essential' SCR domains have been removed. Here, we report the in vitro and in vivo effects of a mini-complement factor H protein, FH1-5^18-20, using the unique factor H-deficient (Cfh-/-) mouse model of C3 glomerulopathy. FH1-5^18-20 is comprised of the key complement regulatory domains (SCRs 1-5) linked to the surface recognition domains (SCRs 18-20). Intraperitoneal injection of FH1-5^18-20 in Cfh-/- mice reduced abnormal glomerular C3 deposition, similar to full-length factor H. Systemic effects on plasma alternative pathway control were comparatively modest, in association with a short half-life. Thus, FH1-5^18-20 is a potential therapeutic agent for C3 glomerulopathy and other renal conditions with alternative pathway-mediated tissue injury.