Belimumab in kidney transplantation: an experimental medicine, randomised, placebo-controlled phase 2 trial.

BACKGROUND: B cells produce alloantibodies and activate alloreactive T cells, negatively affecting kidney transplant survival. By contrast, regulatory B cells are associated with transplant tolerance. Immunotherapies are needed that inhibit B-cell effector function, including antibody secretion, while sparing regulators and minimising infection risk. B lymphocyte stimulator (BLyS) is a cytokine that promotes B-cell activation and has not previously been targeted in kidney transplant recipients. We aimed to determine the safety and activity of an anti-BLyS antibody, belimumab, in addition to standard-of-care immunosuppression in adult kidney transplant recipients. We used an experimental medicine study design with multiple secondary and exploratory endpoints to gain further insight into the effect of belimumab on the generation of de-novo IgG and on the regulatory B-cell compartment. METHODS: We undertook a double-blind, randomised, placebo-controlled phase 2 trial of belimumab, in addition to standard-of-care immunosuppression (basiliximab, mycophenolate mofetil, tacrolimus, and prednisolone) at two centres, Addenbrooke's Hospital, Cambridge, UK, and Guy's and St Thomas' Hospital, London, UK. Participants were eligible if they were aged 18-75 years and receiving a kidney transplant and were planned to receive standard-of-care immunosuppression. Participants were randomly assigned (1:1) to receive either intravenous belimumab 10 mg per kg bodyweight or placebo, given at day 0, 14, and 28, and then every 4 weeks for a total of seven infusions. The co-primary endpoints were safety and change in the concentration of naive B cells from baseline to week 24, both of which were analysed in all patients who received a transplant and at least one dose of drug or placebo (the modified intention-to-treat [mITT] population). This trial has been completed and is registered with ClinicalTrials.gov, NCT01536379, and EudraCT, 2011-006215-56. FINDINGS: Between Sept 13, 2013, and Feb 8, 2015, of 303 patients assessed for eligibility, 28 kidney transplant recipients were randomly assigned to receive belimumab (n=14) or placebo (n=14). 25 patients (12 [86%] patients assigned to the belimumab group and 13 [93%] patients assigned to the placebo group) received a transplant and were included in the mITT population. We observed similar proportions of adverse events in the belimumab and placebo groups, including serious infections (one [8%] of 12 in the belimumab group and five [38%] of 13 in the placebo group during the 6-month on-treatment phase; and none in the belimumab group and two [15%] in the placebo group during the 6-month follow-up). In the on-treatment phase, one patient in the placebo group died because of fatal myocardial infarction and acute cardiac failure. The co-primary endpoint of a reduction in naive B cells from baseline to week 24 was not met. Treatment with belimumab did not significantly reduce the number of naive B cells from baseline to week 24 (adjusted mean difference between the belimumab and placebo treatment groups -34·4 cells per µL, 95% CI -109·5 to 40·7). INTERPRETATION: Belimumab might be a useful adjunct to standard-of-care immunosuppression in renal transplantation, with no major increased risk of infection and potential beneficial effects on humoral alloimmunity. FUNDING: GlaxoSmithKline.

CSF1 Restores Innate Immunity After Liver Injury in Mice and Serum Levels Indicate Outcomes of Patients With Acute Liver Failure.

BACKGROUND & AIMS: Liver regeneration requires functional liver macrophages, which provide an immune barrier that is compromised after liver injury. The numbers of liver macrophages are controlled by macrophage colony-stimulating factor (CSF1). We examined the prognostic significance of the serum level of CSF1 in patients with acute liver injury and studied its effects in mice. METHODS: We measured levels of CSF1 in serum samples collected from 55 patients who underwent partial hepatectomy at the Royal Infirmary Edinburgh between December 2012 and October 2013, as well as from 78 patients with acetaminophen-induced acute liver failure admitted to the Royal Infirmary Edinburgh or the University of Kansas Medical Centre. We studied the effects of increased levels of CSF1 in uninjured mice that express wild-type CSF1 receptor or a constitutive or inducible CSF1-receptor reporter, as well as in chemokine receptor 2 (Ccr2)-/- mice; we performed fate-tracing experiments using bone marrow chimeras. We administered CSF1-Fc (fragment, crystallizable) to mice after partial hepatectomy and acetaminophen intoxication, and measured regenerative parameters and innate immunity by clearance of fluorescent microbeads and bacterial particles. RESULTS: Serum levels of CSF1 increased in patients undergoing liver surgery in proportion to the extent of liver resected. In patients with acetaminophen-induced acute liver failure, a low serum level of CSF1 was associated with increased mortality. In mice, administration of CSF1-Fc promoted hepatic macrophage accumulation via proliferation of resident macrophages and recruitment of monocytes. CSF1-Fc also promoted transdifferentiation of infiltrating monocytes into cells with a hepatic macrophage phenotype. CSF1-Fc increased innate immunity in mice after partial hepatectomy or acetaminophen-induced injury, with resident hepatic macrophage as the main effector cells. CONCLUSIONS: Serum CSF1 appears to be a prognostic marker for patients with acute liver injury. CSF1 might be developed as a therapeutic agent to restore innate immune function after liver injury.

Tissue-resident macrophages protect the liver from ischemia reperfusion injury via a heme oxygenase-1-dependent mechanism.

Kupffer cells are the resident macrophage population of the liver and have previously been implicated in the pathogenesis of hepatic ischemia-reperfusion injury (IRI). Kupffer cells are the major site of expression of hepatic heme oxygenase-1 (HO-1), which has been shown to have anti-inflammatory actions and to protect animals and cells from oxidative injury. Kupffer cells and circulating monocytes were selectively ablated using liposomal clodronate (LC) in the CD11b DTR mouse before induction of hepatic ischemia. Kupffer cell depletion resulted in loss of HO-1 expression and increased susceptibility to hepatic IRI, whereas ablation of circulating monocytes did not affect IRI phenotype. Targeted deletion of HO-1 rendered mice highly susceptible to hepatic IRI. In vivo, HO-1 deletion resulted in pro-inflammatory Kupffer cell differentiation characterized by enhanced Ly6c and MARCO (macrophage receptor with collagenous structure) expression as well as decreased F4/80 expression, mirrored by an expansion in immature circulating monocytes. In vitro, HO-1 inhibition throughout macrophage differentiation led to increased cell numbers, and pro-inflammatory Ly6c+ CD11c- F4/80- phenotype. These data support a critical role for tissue-resident macrophages in homeostasis following ischemic injury, and a co-dependence of HO-1 expression and tissue-resident macrophage differentiation.

Absence of GP130 cytokine receptor signaling causes extended Stüve-Wiedemann syndrome.

The gene IL6ST encodes GP130, the common signal transducer of the IL-6 cytokine family consisting of 10 cytokines. Previous studies have identified cytokine-selective IL6ST defects that preserve LIF signaling. We describe three unrelated families with at least five affected individuals who presented with lethal Stüve-Wiedemann-like syndrome characterized by skeletal dysplasia and neonatal lung dysfunction with additional features such as congenital thrombocytopenia, eczematoid dermatitis, renal abnormalities, and defective acute-phase response. We identified essential loss-of-function variants in IL6ST (a homozygous nonsense variant and a homozygous intronic splice variant with exon skipping). Functional tests showed absent cellular responses to GP130-dependent cytokines including IL-6, IL-11, IL-27, oncostatin M (OSM), and leukemia inhibitory factor (LIF). Genetic reconstitution of GP130 by lentiviral transduction in patient-derived cells reversed the signaling defect. This study identifies a new genetic syndrome caused by the complete lack of signaling of a whole family of GP130-dependent cytokines in humans and highlights the importance of the LIF signaling pathway in pre- and perinatal development.

Interleukin-18 as a drug repositioning opportunity for inflammatory bowel disease: A Mendelian randomization study.

Support from human genetics increases the probability of success in drug development. However, few examples exist of successful genomically-driven drug repositioning. Given that a Mendelian form of severe enterocolitis is due to up-regulation of the interleukin-18 (IL18) signaling pathway, and pharmacologic inhibition of IL18 has been shown to reverse this enterocolitis, we undertook a Mendelian randomization study to test the causal effect of elevated IL18 levels on inflammatory bowel disease susceptibility (IBD) in 12,882 cases and 21,770 controls. Mendelian randomization is an established method to assess the role of biomarkers in disease etiology in a manner that minimizes confounding and prevents reverse causation. Using three SNPs that explained almost 7% of the variance in IL18 level, we found that each genetically predicted standard deviation increase in IL18 was associated with an increase in IBD susceptibility (odds ratio = 1.22, 95% CI = 1.11-1.34, P-value = 6 × 10-5). This association was further validated in 25,042 IBD cases and 34,915 controls (odds ratio = 1.13, 95% CI = 1.05-1.20). Recently, an anti-IL18 monoclonal antibody, which decreased free IL18 levels, was found to be safe, yet ineffective in a phase II trial for type 2 diabetes. Taken together, these genomic findings implicated IBD as an alternative indication for anti-IL18 therapy, which should be tested in randomized controlled trials.

Negative regulation of soluble Flt-1 and soluble endoglin release by heme oxygenase-1.

BACKGROUND: Preeclampsia is characterized clinically by hypertension and proteinuria. Soluble Flt-1 (sFlt-1; also known as soluble vascular endothelial growth factor receptor-1 [VEGFR-1]) and soluble endoglin (sEng) are elevated in preeclampsia, and their administration to pregnant rats elicits preeclampsia-like symptoms. Heme oxygenase-1 (HO-1) and its metabolite carbon monoxide (CO) exert protective effects against oxidative stimuli. Thus, we hypothesized that HO-1 upregulation may offer protection against preeclampsia by inhibiting sFlt-1 and sEng release. METHODS AND RESULTS: Preeclamptic villous explants secreted high levels of sFlt-1 and sEng. Adenoviral overexpression of HO-1 in endothelial cells inhibited VEGF-mediated sFlt-1 release and interferon-gamma- and tumor necrosis factor-alpha-induced sEng release, whereas HO-1 inhibition potentiated sFlt-1 and sEng production from endothelial cells and placental villous explants. Consistent with these findings, mice lacking HO-1 produced higher levels of sFlt-1 and sEng compared with wild-type mice. Using selective ligands (VEGF-E and placental growth factor) and a receptor-specific inhibitor (SU-1498), we demonstrated that VEGF-induced sFlt-1 release was VEGFR-2 dependent. Furthermore, CO-releasing molecule-2 (CORM-2) or CO decreased sFlt-1 release and inhibited VEGFR-2 phosphorylation. Treatment of endothelial cells with statins upregulated HO-1 and inhibited the release of sFlt-1, whereas vitamins C and E had no effect. CONCLUSIONS: The present study demonstrates that the HO-1/CO pathway inhibits sFlt-1 and sEng release, providing compelling evidence for a protective role of HO-1 in pregnancy, and identifies HO-1 as a novel target for the treatment of preeclampsia.

A molecular signature for delayed graft function.

Chronic kidney disease and associated comorbidities (diabetes, cardiovascular diseases) manifest with an accelerated ageing phenotype, leading ultimately to organ failure and renal replacement therapy. This process can be modulated by epigenetic and environmental factors which promote loss of physiological function and resilience to stress earlier, linking biological age with adverse outcomes post-transplantation including delayed graft function (DGF). The molecular features underpinning this have yet to be fully elucidated. We have determined a molecular signature for loss of resilience and impaired physiological function, via a synchronous genome, transcriptome and proteome snapshot, using human renal allografts as a source of healthy tissue as an in vivo model of ageing in humans. This comprises 42 specific transcripts, related through IFNγ signalling, which in allografts displaying clinically impaired physiological function (DGF) exhibited a greater magnitude of change in transcriptional amplitude and elevated expression of noncoding RNAs and pseudogenes, consistent with increased allostatic load. This was accompanied by increased DNA methylation within the promoter and intragenic regions of the DGF panel in preperfusion allografts with immediate graft function. Pathway analysis indicated that an inability to sufficiently resolve inflammatory responses was enabled by decreased resilience to stress and resulted in impaired physiological function in biologically older allografts. Cross-comparison with publically available data sets for renal pathologies identified significant transcriptional commonality for over 20 DGF transcripts. Our data are clinically relevant and important, as they provide a clear molecular signature for the burden of "wear and tear" within the kidney and thus age-related physiological capability and resilience.

Overcoming Translational Barriers in Acute Kidney Injury: A Report from an NIDDK Workshop.

AKI is a complex clinical condition associated with high mortality, morbidity, and health care costs. Despite improvements in methodology and design of clinical trials, and advances in understanding the underlying pathophysiology of rodent AKI, no pharmacologic agent exists for the prevention or treatment of AKI in humans. To address the barriers that affect successful clinical translation of drug targets identified and validated in preclinical animal models of AKI in this patient population, the National Institute of Diabetes and Digestive and Kidney Diseases convened the "AKI Outcomes: Overcoming Barriers in AKI" workshop on February 10-12, 2015. The workshop used a reverse translational medicine approach to identify steps necessary to achieve clinical success. During the workshop, breakout groups were charged first to design feasible, phase 2, proof-of-concept clinical trials for delayed transplant graft function, prevention of AKI (primary prevention), and treatment of AKI (secondary prevention and recovery). Breakout groups then were responsible for identification of preclinical animal models that would replicate the pathophysiology of the phase 2 proof-of-concept patient population, including primary and secondary end points. Breakout groups identified considerable gaps in knowledge regarding human AKI, our understanding of the pathophysiology of AKI in preclinical animal models, and the fidelity of cellular and molecular targets that have been evaluated preclinically to provide information regarding human AKI of various etiologies. The workshop concluded with attendees defining a new path forward to a better understanding of the etiology, pathology, and pathophysiology of human AKI.

The use of marginal heart beating donor livers for transplantation in the United kingdom.

BACKGROUND: This study investigated the use of deceased heart-beating donor livers offered for transplantation during a 10-year period, during which there has been an increasing disparity between organ supply and demand in the United Kingdom. METHODS: Summary data from the National Transplant Database were analyzed on all 7107 heart-beating cadaveric donor livers offered for transplantation in the United Kingdom between 1996 and 2006, with particular attention to livers that were not retrieved, not transplanted, or that subsequently failed to function after transplantation. RESULTS: The difference between the number of patients registered for liver transplantation in the United Kingdom and those transplanted increased from 132 in 1996 to 333 in 2006, leading to a 77% increase in the number of waiting list deaths. Mean donor age increased by 6.1 (5.7-6.6) years during the period studied, in part because of a reduction in the proportion of donors arising from road fatalities. Despite this, the rate of primary nonfunction remained low (1.7% during 1996-2006). The absolute risk increase of primary nonfunction arising from receipt of a moderately as opposed to mildly steatotic organ was 2.6%, which translates to a "number needed to harm" of 41 patients. CONCLUSIONS: The decline in both the number and the quality of livers offered for transplantation in the United Kingdom during the past 10 years has not been associated with a change in the rate of primary nonfunction. In these times of acute donor shortage, these data may justify a more liberal use of marginal grafts.

Insulin induces heme oxygenase-1 through the phosphatidylinositol 3-kinase/Akt pathway and the Nrf2 transcription factor in renal cells.

Heme oxygenase-1 catalyzes the breakdown of heme and is protective in models of kidney transplantation. In this study we describe the induction of heme oxygenase-1 mRNA and protein by insulin. Following treatment with insulin, a five-fold increase in heme oxygenase-1 mRNA and a four-fold increase in protein expression were observed in renal adenocarcinoma cells; insulin-induced heme oxygenase-1 expression was also demonstrated in mouse primary tubular epithelial cells. The induction of heme oxygenase-1 in renal adenocarcinoma cells was blocked by actinomycin D and cycloheximide and was abolished by the phosphatidylinositol 3-kinase inhibitor, LY294002, but not by the inactive analog LY303511. Overexpressing a dominant-negative form of Akt abrogated the heme oxygenase-1-inducing effects of insulin, whereas cells transfected with a constitutively active Akt construct demonstrated an increase in heme oxygenase-1 promoter activity and protein expression. The transcription factor NF-E2-related factor-2 was found to translocate to the nucleus following insulin treatment in a phosphatidylinositol 3-kinase-dependent manner. Pretreatment with NF-E2-related factor-2 small-interfering RNA abolished insulin-induced heme oxygenase-1 induction. Insulin was also found to activate the mitogen-activated protein kinase cascades p38 and extracellular signal-related kinase; however, inhibition of these pathways with SB202190 and PD98059 did not alter insulin-induced heme oxygenase-1 expression. Thus, insulin induces heme oxygenase-1 mRNA and protein expression in renal cells in a phosphatidylinositol 3-kinase/Akt and NF-E2-related factor-2-dependent manner.

Use of Renal Replacement Therapy May Influence Graft Outcomes following Liver Transplantation for Acute Liver Failure: A Propensity-Score Matched Population-Based Retrospective Cohort Study.

INTRODUCTION: Acute kidney injury is associated with a poor prognosis in acute liver failure but little is known of outcomes in patients undergoing transplantation for acute liver failure who require renal replacement therapy. METHODS: A retrospective analysis of the United Kingdom Transplant Registry was performed (1 January 2001-31 December 2011) with patient and graft survival determined using Kaplan-Meier methods. Cox proportional hazards models were used together with propensity-score based full matching on renal replacement therapy use. RESULTS: Three-year patient and graft survival for patients receiving renal replacement therapy were 77.7% and 72.6% compared with 85.1% and 79.4% for those not requiring renal replacement therapy (P<0.001 and P = 0.009 respectively, n = 725). In a Cox proportional hazards model, renal replacement therapy was a predictor of both patient death (hazard ratio (HR) 1.59, 95% CI 1.01-2.50, P = 0.044) but not graft loss (HR 1.39, 95% CI 0.92-2.10, P = 0.114). In groups fully matched on baseline covariates, those not receiving renal replacement therapy with a serum creatinine greater than 175 µmol/L had a significantly worse risk of graft failure than those receiving renal replacement therapy. CONCLUSION: In patients being transplanted for acute liver failure, use of renal replacement therapy is a strong predictor of patient death and graft loss. Those not receiving renal replacement therapy with an elevated serum creatinine may be at greater risk of early graft failure than those receiving renal replacement therapy. A low threshold for instituting renal replacement therapy may therefore be beneficial.

Ischemic preconditioning in the liver is independent of regulatory T cell activity.

Ischemic preconditioning (IPC) protects organs from ischemia reperfusion injury (IRI) through unknown mechanisms. Effector T cell populations have been implicated in the pathogenesis of IRI, and T regulatory cells (Treg) have become a putative therapeutic target, with suggested involvement in IPC. We explored the role of Treg in hepatic IRI and IPC in detail. IPC significantly reduced injury following ischemia reperfusion insults. Treg were mobilized rapidly to the circulation and liver after IRI, but IPC did not further increase Treg numbers, nor was it associated with modulation of circulating pro-inflammatory chemokine or cytokine profiles. We used two techniques to deplete Treg from mice prior to IRI. Neither Treg depleted FoxP3.LuciDTR mice, nor wildtyoe mice depleted of Tregs with PC61, were more susceptible to IRI compared with controls. Despite successful enrichment of Treg in the liver, by adoptive transfer of both iTreg and nTreg or by in vivo expansion of Treg with IL-2/anti-IL-2 complexes, no protection against IRI was observed.We have explored the role of Treg in IRI and IPC using a variety of techniques to deplete and enrich them within both the liver and systemically. This work represents an important negative finding that Treg are not implicated in IPC and are unlikely to have translational potential in hepatic IRI.

Heme oxygenase system in hepatic ischemia-reperfusion injury.

Hepatic ischemia-reperfusion injury (IRI) limits access to transplantation. Heme oxygenase-1 (HO-1) is a powerful antioxidant enzyme which degrades free heme into biliverdin, free iron and carbon monoxide. HO-1 and its metabolites have the ability to modulate a wide variety of inflammatory disorders including hepatic IRI. Mechanisms of this protective effect include reduction of oxygen free radicals, alteration of macrophage and T cell phenotype. Further work is required to understand the physiological importance of the many actions of HO-1 identified experimentally, and to harness the protective effect of HO-1 for therapeutic potential.

c-Jun terminal kinase-2 gene deleted mice overexpress hemeoxygenase-1 and are protected from hepatic ischemia reperfusion injury.

BACKGROUND: Targeted deletion of c-jun amino terminal kinase-2 (jnk-2) upregulates the activator protein-1 transcription factor system. We hypothesized that this would lead to induction of hemeoxygenase-1 (HO-1) and confer protection from hepatic ischemia reperfusion injury. METHODS: Wild-type and jnk-2 -/- animals were subjected to hepatic ischemia reperfusion insults in two models: a total hepatic ischemia model involving timed Pringle maneuver, and a partial hepatic ischemia model involving selective occlusion of the portal pedicle supplying the left hepatic lobe. Optimal durations of injury were calibrated for each model. After 24 hr, animals were killed, and blood and tissues were collected for alanine aminotransferase, histologic injury scoring, and other analyses. Before total or partial hepatic ischemia reperfusion insults, some animals were subject to HO-1 inhibition with chromium mesoporphyrin IX or Kupffer cell depletion with liposomal clodronate. Bone marrow-derived monocytes were grown from hemopoietic progenitors taken from wild-type and jnk-2 -/- mice before stimulation with lipopolysaccharide and measurement of tumour necrosis factor-alpha production. RESULTS: Jnk-2 -/- animals were protected from hepatic ischemia reperfusion injury. HO-1 expression and activity was elevated in jnk-2 -/- animals (2.2-fold; P=0.006). Most HO-1 was expressed in Kupffer cells. Inhibition of HO-1 in jnk-2 -/- animals led to the loss of protection from ischemia. Depletion of Kupffer cells using liposomal clodronate led to loss of hepatic HO-1 expression and much more severe injury in wild-type and jnk-2 -/- animals. In vitro studies of cultured macrophages demonstrated reduced tumour necrosis factor-alpha secretion after lipopolysaccharide stimulus, an effect lost after HO-1 inhibition.

Heat shock protein 90-binding agents protect renal cells from oxidative stress and reduce kidney ischemia-reperfusion injury.

Heat shock proteins (Hsps) are protective in models of transplantation, yet practical strategies to upregulate them remain elusive. The heat shock protein 90-binding agent (HBA) geldanamycin and its analogs (17-AAG and 17-DMAG) are known to upregulate Hsps and confer cellular protection but have not been investigated in a model relevant to transplantation. We examined the ability of HBAs to upregulate Hsp expression and confer protection in renal adenocarcinoma (ACHN) cells in vitro and in a mouse model of kidney ischemia-reperfusion (I/R) injury. Hsp70 gene expression was increased 30-40 times in ACHN cells treated with HBAs, and trimerization and DNA binding of heat shock transcription factor-1 (HSF1) were demonstrated. A three- and twofold increase in Hsp70 and Hsp27 protein expression, respectively, was found in ACHN cells treated with HBAs. HBAs protected ACHN cells from an H2O2-mediated oxidative stress, and HSF1 short interfering RNA was found to abrogate HBA-mediated Hsp induction and protection. In vivo, Hsp70 was upregulated in the kidneys, liver, lungs, and heart of HBA-treated mice. This was associated with a functional and morphological renal protection from I/R injury. Therefore, HBAs mediate upregulation of protective Hsps in mouse kidneys which are associated with reduced I/R injury and may be useful in reducing transplant-associated kidney injury.

"Off-pump" repair of a postangioplasty coronary artery bleed.

Following percutaneous multivessel coronary stent implantation with full anticoagulation, a 65-year-old man suffered tamponade and cardiac arrest. After successful resuscitation, he underwent repeat coronary angiography which demonstrated extravasation of contrast from a distal circumflex subbranch. Thereafter, he was transferred to the cardiothoracic surgery unit where the leaking vessel was oversewn using the Medtronic Octopus Retractor for stabilization. This report illustrates the growing wider use of "off-pump" techniques beyond coronary artery bypass grafting. In this case, the patient was exposed to a much shorter procedure with less morbidity than could have been expected had cardiopulmonary bypass been used.