Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Gα12 signaling regulates transcriptional and phenotypic responses that promote glioblastoma tumor invasion

In silico interrogation of glioblastoma (GBM) in The Cancer Genome Atlas (TCGA) revealed upregulation of GNA12 (Gα12), encoding the alpha subunit of the heterotrimeric G-protein G12, concomitant with overexpression of multiple G-protein coupled receptors (GPCRs) that signal through Gα12. Glioma stem cell lines from patient-derived xenografts also showed elevated levels of Gα12. Knockdown (KD) of Gα12 was carried out in two different human GBM stem cell (GSC) lines. Tumors generated in vivo by orthotopic injection of Gα12KD GSC cells showed reduced invasiveness, without apparent changes in tumor size or survival relative to control GSC tumor-bearing mice. Transcriptional profiling of GSC-23 cell tumors revealed significant differences between WT and Gα12KD tumors including reduced expression of genes associated with the extracellular matrix, as well as decreased expression of stem cell genes and increased expression of several proneural genes. Thrombospondin-1 (THBS1), one of the genes most repressed by Gα12 knockdown, was shown to be required for Gα12-mediated cell migration in vitro and for in vivo tumor invasion. Chemogenetic activation of GSC-23 cells harboring a Gα12-coupled DREADD also increased THBS1 expression and in vitro invasion. Collectively, our findings implicate Gα12 signaling in regulation of transcriptional reprogramming that promotes invasiveness, highlighting this as a potential signaling node for therapeutic intervention.

A gain-of-function p53 mutant synergizes with oncogenic NRAS to promote acute myeloid leukemia in mice

We previously demonstrated that a subset of acute myeloid leukemia (AML) patients with concurrent RAS pathway and TP53 mutations have an extremely poor prognosis and that most of these TP53 mutations are missense mutations. Here, we report that, in contrast to the mixed AML and T cell malignancy that developed in NrasG12D/+ p53-/- (NP-/-) mice, NrasG12D/+ p53R172H/+ (NPmut) mice rapidly developed inflammation-associated AML. Under the inflammatory conditions, NPmut hematopoietic stem and progenitor cells (HSPCs) displayed imbalanced myelopoiesis and lymphopoiesis and mostly normal cell proliferation despite MEK/ERK hyperactivation. RNA-Seq analysis revealed that oncogenic NRAS signaling and mutant p53 synergized to establish an NPmut-AML transcriptome distinct from that of NP-/- cells. The NPmut-AML transcriptome showed GATA2 downregulation and elevated the expression of inflammatory genes, including those linked to NF-κB signaling. NF-κB was also upregulated in human NRAS TP53 AML. Exogenous expression of GATA2 in human NPmut KY821 AML cells downregulated inflammatory gene expression. Mouse and human NPmut AML cells were sensitive to MEK and NF-κB inhibition in vitro. The proteasome inhibitor bortezomib stabilized the NF-κB-inhibitory protein IκBα, reduced inflammatory gene expression, and potentiated the survival benefit of a MEK inhibitor in NPmut mice. Our study demonstrates that a p53 structural mutant synergized with oncogenic NRAS to promote AML through mechanisms distinct from p53 loss.

HAPLN1 matrikine: a bone marrow homing factor linked to poor outcomes in patients with MM

The bone marrow (BM) microenvironment is critical for dissemination, growth, and survival of multiple myeloma (MM) cells. Homing of myeloma cells to the BM niche is a crucial step in MM dissemination, but the mechanisms involved are incompletely understood. In particular, any role of matrikines, neofunctional peptides derived from extracellular matrix proteins, remains unknown. Here, we report that a matrikine derived from hyaluronan and proteoglycan link protein 1 (HAPLN1) induces MM cell adhesion to the BM stromal components, such as fibronectin, endothelial cells, and stromal cells and, furthermore, induces their chemotactic and chemokinetic migration. In a mouse xenograft model, we show that MM cells preferentially home to HAPLN1 matrikine-conditioned BM. The transcription factor STAT1 is activated by HAPLN1 matrikine and is necessary to induce MM cell adhesion, migration, migration-related genes, and BM homing. STAT1 activation is mediated by interferon beta (IFN-β), which is induced by NF-κB after stimulation by HAPLN1 matrikine. Finally, we also provide evidence that higher levels of HAPLN1 in BM samples correlate with poorer progression-free survival of patients with newly diagnosed MM. These data reveal that a matrikine present in the BM microenvironment acts as a chemoattractant, plays an important role in BM homing of MM cells via NF-κB-IFN-β-STAT1 signaling, and may help identify patients with poor outcomes. This study also provides a mechanistic rationale for targeting HAPLN1 matrikine in MM therapy.

Several Alphaherpesviruses Interact Similarly with the NF-κB Pathway and Suppress NF-κB-Dependent Gene Expression

Alphaherpesvirus infection is associated with attenuation of different aspects of the host innate immune response that is elicited to confine primary infections at the mucosal epithelia. Here, we report that infection of epithelial cells with several alphaherpesviruses of different species, including herpes simplex virus 1 and 2 (HSV-1 and HSV-2), feline alphaherpesvirus 1 (FHV-1), and bovine alphaherpesvirus 1 (BoHV-1) results in the inactivation of the responses driven by the nuclear factor kappa B (NF-κB) pathway, considered a pillar of the innate immune response. The mode to interact with and circumvent NF-κB-driven responses in infected epithelial cells is seemingly conserved in human, feline, and porcine alphaherpesviruses, consisting of a persistent activation of the NF-κB cascade but a potent repression of NF-κB-dependent transcription activity, which relies on replication of viral genomes. However, BoHV-1 apparently deviates from the other investigated members of the taxon in this respect, as BoHV-1-infected epithelial cells do not display the persistent NF-κB activation observed for the other alphaherpesviruses. In conclusion, this study suggests that inhibition of NF-κB transcription activity is a strategy used by several alphaherpesviruses to prevent NF-κB-driven responses in infected epithelial cells. IMPORTANCE The current study provides a side-by-side comparison of the interaction of different alphaherpesviruses with NF-κB, a key and central player in the (proinflammatory) innate host response, in infected nontransformed epithelial cell lines. We report that all studied viruses prevent expression of the hallmark NF-κB-dependent gene IκB, often but not always via similar strategies, pointing to suppression of NF-κB-dependent host gene expression in infected epithelial cells as a common and therefore likely important aspect of alphaherpesviruses.

Role of mitochondria-bound HK2 in rheumatoid arthritis fibroblast-like synoviocytes

Background

Glucose metabolism, specifically, hexokinase 2 (HK2), has a critical role in rheumatoid arthritis (RA) fibroblast-like synoviocyte (FLS) phenotype. HK2 localizes not only in the cytosol but also in the mitochondria, where it protects mitochondria against stress. We hypothesize that mitochondria-bound HK2 is a key regulator of RA FLS phenotype.

Methods

HK2 localization was evaluated by confocal microscopy after FLS stimulation. RA FLSs were infected with Green fluorescent protein (GFP), full-length (FL)-HK2, or HK2 lacking its mitochondrial binding motif (HK2ΔN) expressing adenovirus (Ad). RA FLS was also incubated with methyl jasmonate (MJ; 2.5 mM), tofacitinib (1 µM), or methotrexate (1 µM). RA FLS was tested for migration and invasion and gene expression. Gene associations with HK2 expression were identified by examining single-cell RNA sequencing (scRNA-seq) data from murine models of arthritis. Mice were injected with K/BxN serum and given MJ. Ad-FLHK2 or Ad-HK2ΔN was injected into the knee of wild-type mice.

Results

Cobalt chloride (CoCl2) and platelet-derived growth factor (PDGF) stimulation induced HK2 mitochondrial translocation. Overexpression of the HK2 mutant and MJ incubation reversed the invasive and migrative phenotype induced by FL-HK2 after PDGF stimulation, and MJ also decreased the expression of C-X-C Motif Chemokine Ligand 1 (CXCL1) and Collagen Type I Alpha 1 Chain (COL1A1). Of interest, tofacitinib but not methotrexate had an effect on HK2 dissociation from the mitochondria. In murine models, MJ treatment significantly decreased arthritis severity, whereas HK2FL was able to induce synovial hypertrophy as opposed to HK2ΔN.

Conclusion

Our results suggest that mitochondrial HK2 regulates the aggressive phenotype of RA FLS. New therapeutic approaches to dissociate HK2 from mitochondria offer a safer approach than global glycolysis inhibition.

RHOA, a small G-protein, signals to mitophagy through regulation of PINK1 protein stability and protects cardiomyocytes against ischemia

RHOA (ras homolog family member A) is a small G-protein that regulates a range of cellular processes including cell growth and survival. RHOA is a proximal downstream effector of G protein-coupled receptors coupling to GNA12/Gα12-GNA13/Gα13 proteins, and is activated in response to stretch and oxidative stress, functioning as a stress-response molecule. It has been demonstrated that RHOA signaling provides cardioprotection through inhibition of mitochondrial death pathways. Mitochondrial integrity is preserved not only by inhibition of mitochondrial death pathways but also by mitochondrial quality control mechanisms including mitophagy. One of the most well-established mechanisms of mitophagy is the mitochondrial membrane depolarization-dependent PINK1-PRKN/Parkin pathway. However, depolarization of the mitochondrial membrane potential is a late-stage event that occurs just before cell death, and additional intracellular mechanisms that enhance the PINK1-PRKN pathway have not been fully determined. We recently discovered that RHOA activation engages a unique mechanism to regulate PINK1 protein stability without inducing mitochondrial membrane depolarization, leading to increased mitophagy and protection against ischemia in cardiomyocytes. Our results suggest regulation of RHOA signaling as a potential strategy to enhance protective mitophagy against stress without compromising mitochondrial functions.

Ectopic CH60 mediates HAPLN1-induced cell survival signaling in multiple myeloma

Multiple myeloma (MM), the second most common hematological malignancy, is generally considered incurable because of the development of drug resistance. We previously reported that hyaluronan and proteoglycan link protein 1 (HAPLN1) produced by stromal cells induces activation of NF-κB, a tumor-supportive transcription factor, and promotes drug resistance in MM cells. However, the identity of the cell surface receptor that detects HAPLN1 and thereby engenders pro-tumorigenic signaling in MM cells remains unknown. Here, we performed an unbiased cell surface biotinylation assay and identified chaperonin 60 (CH60) as the direct binding partner of HAPLN1 on MM cells. Cell surface CH60 specifically interacted with TLR4 to evoke HAPLN1-induced NF-κB signaling, transcription of anti-apoptotic genes, and drug resistance in MM cells. Collectively, our findings identify a cell surface CH60-TLR4 complex as a HAPLN1 receptor and a potential molecular target to overcome drug resistance in MM cells.

HAPLN1 confers multiple myeloma cell resistance to several classes of therapeutic drugs

Multiple myeloma (MM), a malignant plasma cell infiltration of the bone marrow, is generally considered incurable: resistance to multiple therapeutic drugs inevitably arises from tumor cell-intrinsic and tumor microenvironment (TME)-mediated mechanisms. Here we report that the proteoglycan tandem repeat 1 (PTR1) domain of the TME matrix protein, hyaluronan and proteoglycan link protein 1 (HAPLN1), induces a host of cell survival genes in MM cells and variable resistance to different classes of clinical drugs, including certain proteasome inhibitors, steroids, immunomodulatory drugs, and DNA damaging agents, in several MM cell lines tested. Collectively, our study identifies HAPLN1 as an extracellular matrix factor that can simultaneously confer MM cell resistance to multiple therapeutic drugs.

RhoA signaling increases mitophagy and protects cardiomyocytes against ischemia by stabilizing PINK1 protein and recruiting Parkin to mitochondria

Mitophagy, a mitochondria-specific form of autophagy, removes dysfunctional mitochondria and is hence an essential process contributing to mitochondrial quality control. PTEN-induced kinase 1 (PINK1) and the E3 ubiquitin ligase Parkin are critical molecules involved in stress-induced mitophagy, but the intracellular signaling mechanisms by which this pathway is regulated are unclear. We tested the hypothesis that signaling through RhoA, a small GTPase, induces mitophagy via modulation of the PINK1/Parkin pathway as a protective mechanism against ischemic stress. We demonstrate that expression of constitutively active RhoA as well as sphingosine-1-phosphate induced activation of endogenous RhoA in cardiomyocytes result in an accumulation of PINK1 at mitochondria. This is accompanied by translocation of Parkin to mitochondria and ubiquitination of mitochondrial proteins leading to recognition of mitochondria by autophagosomes and their lysosomal degradation. Expression of RhoA in cardiomyocytes confers protection against ischemia, and this cardioprotection is attenuated by siRNA-mediated PINK1 knockdown. In vivo myocardial infarction elicits increases in mitochondrial PINK1, Parkin, and ubiquitinated mitochondrial proteins. AAV9-mediated RhoA expression potentiates these responses and a concurrent decrease in infarct size is observed. Interestingly, induction of mitochondrial PINK1 accumulation in response to RhoA signaling is neither mediated through its transcriptional upregulation nor dependent on depolarization of the mitochondrial membrane, the canonical mechanism for PINK1 accumulation. Instead, our results reveal that RhoA signaling inhibits PINK1 cleavage, thereby stabilizing PINK1 protein at mitochondria. We further show that active RhoA localizes at mitochondria and interacts with PINK1, and that the mitochondrial localization of RhoA is regulated by its downstream effector protein kinase D. These findings demonstrate that RhoA activation engages a unique mechanism to regulate PINK1 accumulation, induce mitophagy and protect against ischemic stress, and implicates regulation of RhoA signaling as a potential strategy to enhance mitophagy and confer protection under stress conditions.

The SUMO protease SENP1 promotes aggressive behaviors of high HIF2α expressing renal cell carcinoma cells

While an important role for the SUMO protease SENP1 is recognized in multiple solid cancers, its role in renal cell carcinoma (RCC) pathogenesis, particularly the most dominant subtype, clear cell RCC (ccRCC), is poorly understood. Here we show that a combination of high HIF2α and SENP1 expression in ccRCC samples predicts poor patient survival. Using ccRCC cell models that express high HIF2α but low SENP1, we show that overexpression of SENP1 reduces sumoylation and ubiquitination of HIF2α, increases HIF2α transcriptional activity, and enhances expression of genes associated with cancer cell invasion, stemness and epithelial-mesenchymal transition. Accordingly, ccRCC cells with high HIF2α and SENP1 showed increased invasion and sphere formation in vitro, and local invasion and metastasis in vivo. Finally, SENP1 overexpression caused high HIF2α ccRCC cells to acquire resistance to a clinical mTOR inhibitor, everolimus. These results reveal a combination of high SENP1 and HIF2α expression gives particularly poor prognosis for ccRCC patients and suggest that SENP1 may be an attractive new target for treating metastatic RCC (mRCC).

A Hyaluronan and Proteoglycan Link Protein 1 Matrikine: Role of Matrix Metalloproteinase 2 in Multiple Myeloma NF-κB Activation and Drug Resistance

The NF-κB signaling pathway plays key roles in inflammation and the pathogenesis of many solid and hematologic malignancies, including multiple myeloma, a malignancy of the plasma cells. While proteasome inhibitors, such as bortezomib, employed in multiple myeloma treatments may inhibit NF-κB signaling pathways, multiple myeloma cells often become drug resistant in part due to non-cell autonomous mechanism(s) from the multiple myeloma tumor microenvironment. We previously found that fragments of, but not full-length, hyaluronan and proteoglycan link protein 1 (HAPLN1), produced by multiple myeloma bone marrow stromal cells (BMSC), activate an atypical bortezomib-resistant NF-κB pathway in multiple myeloma cells. In our current study, we found that multiple myeloma cells promote HAPLN1 expression and matrix metalloproteinase 2 (MMP2) activity in cocultured BMSCs and MMP2 activity is higher in BMSCs established from multiple myeloma patients' BM aspirates relative to normal equivalents. Moreover, MMP2 cleaves HAPLN1 into forms similar in size to those previously observed in patients with multiple myeloma with progressive disease. Both HAPLN1 and MMP2 in BMSCs were required to enhance NF-κB activation and resistance to bortezomib-induced cell death in cocultured multiple myeloma cells. We propose that MMP2-processing of HAPLN1 produces a matrikine that induces NF-κB activation and promotes bortezomib resistance in multiple myeloma cells.

IMPLICATIONS

HAPLN1 and MMP2 produced by BMSCs obtained from patients with multiple myeloma promote NF-κB activity and resistance to bortezomib toxicity in multiple myeloma cells, uncovering their potential as biomarkers or therapeutic targets to address bortezomib resistance in patients with multiple myeloma.

Larger Posterior Revascularization Associated with Reduction of Choroidal Anastomosis in Moyamoya Disease: A Quantitative Angiographic Analysis

BACKGROUND AND PURPOSE

Choroidal anastomosis, a hemorrhage-prone periventricular collateral manifestation in Moyamoya disease, outflows to the cortex posterior to the central sulcus. The objective of the present study was to test whether the angiographic extent of revascularization posterior to the central sulcus contributes to the postoperative reduction of choroidal anastomosis.

MATERIALS AND METHODS

This retrospective cohort study included choroidal anastomosis-positive hemispheres before direct bypass surgery. The postoperative reduction of choroidal anastomosis was determined by a consensus of 2 raters according to the previous research. An imaging software automatically traced the angiographic revascularization area, which was subsequently divided into anterior and posterior parts by an anatomic line corresponding to the central sulcus. Each area was quantitatively measured as a percentage relative to the whole supratentorial area.

RESULTS

Postoperative reduction of choroidal anastomosis was achieved in 68 (85.0%) of the 80 included hemispheres. The revascularization area posterior to the central sulcus was significantly larger in the hemispheres with reduction than in those with no reduction (mean, 15.2% [SD, 7.1%] versus 4.2% [SD, 3.4%], P < .001), whereas no significant difference was observed in the revascularization area anterior to the central sulcus. Multivariate analysis revealed that the revascularization area posterior to the central sulcus was the only significant factor associated with reduction (OR, 1.57; 95% CI, 1.21-2.03, for every 1% increase).

CONCLUSIONS

The results suggest that a larger revascularization posterior to the central sulcus is associated with postoperative reduction of choroidal anastomosis regardless of the extent of anterior revascularization. It might facilitate optimal selection of the revascularization site for preventing hemorrhage.

Pseudorabies Virus Infection Results in a Broad Inhibition of Host Gene Transcription

Pseudorabies virus (PRV) is a porcine alphaherpesvirus that belongs to the Herpesviridae family. We showed earlier that infection of porcine epithelial cells with PRV triggers activation of the nuclear factor κB (NF-κB) pathway, a pivotal signaling axis in the early immune response. However, PRV-induced NF-κB activation does not lead to NF-κB-dependent gene expression. Here, using electrophoretic mobility shift assays (EMSAs), we show that PRV does not disrupt the ability of NF-κB to interact with its κB target sites. Assessing basal cellular transcriptional activity in PRV-infected cells by quantitation of prespliced transcripts of constitutively expressed genes uncovered a broad suppression of cellular transcription by PRV, which also affects the inducible expression of NF-κB target genes. Host cell transcription inhibition was rescued when viral genome replication was blocked using phosphonoacetic acid (PAA). Remarkably, we found that host gene expression shutoff in PRV-infected cells correlated with a substantial retention of the NF-κB subunit p65, the TATA box binding protein, and RNA polymerase II-essential factors required for (NF-κB-dependent) gene transcription-in expanding PRV replication centers in the nucleus and thereby away from the host chromatin. This study reveals a potent mechanism used by the alphaherpesvirus PRV to steer the protein production capacity of infected cells to viral proteins by preventing expression of host genes, including inducible genes involved in mounting antiviral responses. IMPORTANCE Herpesviruses are highly successful pathogens that cause lifelong persistent infections of their host. Modulation of the intracellular environment of infected cells is imperative for the success of virus infections. We reported earlier that a DNA damage response in epithelial cells infected with the alphaherpesvirus pseudorabies virus (PRV) results in activation of the hallmark proinflammatory NF-κB signaling axis but, remarkably, that this activation does not lead to NF-κB-induced (proinflammatory) gene expression. Here, we report that PRV-mediated inhibition of host gene expression stretches beyond NF-κB-dependent gene expression and in fact reflects a broad inhibition of host gene transcription, which correlates with a substantial recruitment of essential host transcription factors in viral replication compartments in the nucleus, away from the host chromatin. These data uncover a potent alphaherpesvirus mechanism to interfere with production of host proteins, including proteins involved in antiviral responses.

Timelapse viability assay to detect division and death of primary multiple myeloma cells in response to drug treatments with single cell resolution

Heterogeneity among cancer cells and in the tumor microenvironment (TME) is thought to be a significant contributor to the heterogeneity of clinical therapy response observed between patients and can evolve over time. A primary example of this is multiple myeloma (MM), a generally incurable cancer where such heterogeneity contributes to the persistent evolution of drug resistance. However, there is a paucity of functional assays for studying this heterogeneity in patient samples or for assessing the influence of the patient TME on therapy response. Indeed, the population-averaged data provided by traditional drug response assays and the large number of cells required for screening remain significant hurdles to advancement. To address these hurdles, we developed a suite of accessible technologies for quantifying functional drug response to a panel of therapies in ex vivo three-dimensional culture using small quantities of a patient's own cancer and TME components. This suite includes tools for label-free single-cell identification and quantification of both cell division and death events with a standard brightfield microscope, an open-source software package for objective image analysis and feasible data management of multi-day timelapse experiments, and a new approach to fluorescent detection of cell death that is compatible with long-term imaging of primary cells. These new tools and capabilities are used to enable sensitive, objective, functional characterization of primary MM cell therapy response in the presence of TME components, laying the foundation for future studies and efforts to enable predictive assessment drug efficacy for individual patients.

ATPase Inhibitory Factor-1 Disrupts Mitochondrial Ca2+ Handling and Promotes Pathological Cardiac Hypertrophy through CaMKIIδ

ATPase inhibitory factor-1 (IF1) preserves cellular ATP under conditions of respiratory collapse, yet the function of IF1 under normal respiring conditions is unresolved. We tested the hypothesis that IF1 promotes mitochondrial dysfunction and pathological cardiomyocyte hypertrophy in the context of heart failure (HF). Methods and results: Cardiac expression of IF1 was increased in mice and in humans with HF, downstream of neurohumoral signaling pathways and in patterns that resembled the fetal-like gene program. Adenoviral expression of wild-type IF1 in primary cardiomyocytes resulted in pathological hypertrophy and metabolic remodeling as evidenced by enhanced mitochondrial oxidative stress, reduced mitochondrial respiratory capacity, and the augmentation of extramitochondrial glycolysis. Similar perturbations were observed with an IF1 mutant incapable of binding to ATP synthase (E55A mutation), an indication that these effects occurred independent of binding to ATP synthase. Instead, IF1 promoted mitochondrial fragmentation and compromised mitochondrial Ca2+ handling, which resulted in sarcoplasmic reticulum Ca2+ overloading. The effects of IF1 on Ca2+ handling were associated with the cytosolic activation of calcium-calmodulin kinase II (CaMKII) and inhibition of CaMKII or co-expression of catalytically dead CaMKIIδC was sufficient to prevent IF1 induced pathological hypertrophy. Conclusions: IF1 represents a novel member of the fetal-like gene program that contributes to mitochondrial dysfunction and pathological cardiac remodeling in HF. Furthermore, we present evidence for a novel, ATP-synthase-independent, role for IF1 in mitochondrial Ca2+ handling and mitochondrial-to-nuclear crosstalk involving CaMKII.

SiglecF(HI) Marks Late-Stage Neutrophils of the Infarcted Heart: A Single-Cell Transcriptomic Analysis of Neutrophil Diversification

Background

Neutrophils are thought to be short‐lived first responders to tissue injuries such as myocardial infarction (MI), but little is known about their diversification or dynamics.

Methods and Results

We permanently ligated the left anterior descending coronary arteries of mice and performed single‐cell RNA sequencing and analysis of >28 000 neutrophil transcriptomes isolated from the heart, peripheral blood, and bone marrow of mice on days 1 to 4 after MI or at steady‐state. Unsupervised clustering of cardiac neutrophils revealed 5 major subsets, 3 of which originated in the bone marrow, including a late‐emerging granulocyte expressing SiglecF, a marker classically used to define eosinophils. SiglecF^HI neutrophils represented ≈25% of neutrophils on day 1 and grew to account for >50% of neutrophils by day 4 post‐MI. Validation studies using quantitative polymerase chain reaction of fluorescent‐activated cell sorter sorted Ly6G⁺SiglecF^HI and Ly6G⁺SiglecF^LO neutrophils confirmed the distinct nature of these populations. To confirm that the cells were neutrophils rather than eosinophils, we infarcted GATA‐deficient mice (∆dblGATA) and observed similar quantities of infiltrating Ly6G⁺SiglecF^HI cells despite marked reductions of conventional eosinophils. In contrast to other neutrophil subsets, Ly6G⁺SiglecF^HI neutrophils expressed high levels of Myc‐regulated genes, which are associated with longevity and are consistent with the persistence of this population on day 4 after MI.

Conclusions

Overall, our data provide a spatial and temporal atlas of neutrophil specialization in response to MI and reveal a dynamic proinflammatory cardiac Ly6G⁺SigF⁺(Myc⁺NFϰB⁺) neutrophil that has been overlooked because of negative selection.

Cortical Distribution of Fragile Periventricular Anastomotic Collateral Vessels in Moyamoya Disease: An Exploratory Cross-Sectional Study of Japanese Patients with Moyamoya Disease

BACKGROUND AND PURPOSE

Collateral vessels in Moyamoya disease represent potential sources of bleeding. To test whether these cortical distributions vary among subtypes, we investigated cortical terminations using both standardized MR imaging and MRA.

MATERIALS AND METHODS

Patients with Moyamoya disease who underwent MR imaging with MRA in our institution were enrolled in this study. MRA was spatially normalized to the Montreal Neurological Institute space; then, collateral vessels were measured on MRA and classified into 3 types of anastomosis according to the parent artery: lenticulostriate, thalamic, and choroidal. We also obtained the coordinates of collateral vessel outflow to the cortex. Differences in cortical terminations were compared among the 3 types of anastomosis.

RESULTS

We investigated 219 patients with Moyamoya disease, and a total of 190 collateral vessels (lenticulostriate anastomosis, n = 72; thalamic anastomosis, n = 21; choroidal anastomosis, n = 97) in 46 patients met the inclusion criteria. We classified the distribution patterns of collateral anastomosis as follows: lenticulostriate collaterals outflowing anteriorly (P < .001; 95% CI, 67.0-87.0) and medially (P < .001; 95% CI, 11.0-24.0) more frequently than choroidal collaterals; lenticulostriate collaterals outflowing anteriorly more frequently than thalamic collaterals (P < .001; 95% CI, 34.0-68.0); and choroidal collaterals outflowing posteriorly more frequently than thalamic collaterals (P < .001; 95% CI, 14.0-34.0). Lenticulostriate anastomoses outflowed to the superior or inferior frontal sulcus and interhemispheric fissure. Thalamic anastomoses outflowed to the insular cortex and cortex around the central sulcus. Choroidal anastomoses outflowed to the cortex posterior to the central sulcus and the insular cortex.

CONCLUSIONS

Cortical distribution patterns appear to differ markedly among the 3 types of collaterals.

Long-term outcomes of Japan-specific dosage of rivaroxaban in high-risk patients with non-valvular atrial fibrillation: analysis from the XAPASS

Background

XAPASS is a real-world, prospective, single-arm, observational study conducted as a post-marketing surveillance mandated by the health authority in Japan. Nowadays, direct oral anticoagulant therapy using factor Xa or thrombin inhibitor has been the standard of care for patients with non-valvular atrial fibrillation (NVAF) to prevent ischemic stroke. However, the clinical impact of reduced dosage (approved dose of 15 or 10 mg once daily in Japan is relatively reduced compared to global dosage) factor Xa inhibitor rivaroxaban in high-risk patients remains unclear.

Purpose

The present sub-analysis of XAPASS was carried out to assess long-term safety and effectiveness of reduced-dose rivaroxaban in high-risk NVAF patients for bleeding and thromboembolism.

Methods

All patients with NVAF who were newly started on rivaroxaban were eligible for surveillance. The principal safety outcome was a composite of major and non-major bleeding events, and the primary effectiveness outcome was a composite of ischaemic stroke, haemorrhagic stroke, non-central nervous system systemic embolism (non-CNS SE), and myocardial infarction (MI). In this present sub-analysis, high-risk patients were defined as those who had two of the following three risk factors: elderly (≥75 years old), low body weight (≤50 kg), and renal impairment (CrCl &lt;50 mL/min).

Results

In total, 11,308 patients were enrolled between April 2012 and June 2014 from 1,419 hospitals, and overall data were analysed from 10,664 patients from whom data were collected. Among them, 3,694 patients matched the criteria for the high-risk patients defined in this sub-analysis, and 6,970 patients did not match the criteria (non-high-risk patients). The mean treatment duration was 791±673 days in the high-risk patients and 944±709 days in the non-high-risk patients. Mean patient age was 80.9±5.5 years and 69.0±9.0 years at baseline, respectively. Mean CHADS2 score was 2.8 and 1.8, and CHA2DS2-VASc score was 4.4 and 2.9, respectively. The rates of CHADS2 component comorbidities were lower in the non-high-risk patients except for diabetes mellitus. The incidence rates of any bleeding, major bleeding, and the primary effectiveness outcomes were 4.8, 1.6, and 2.1%/patient-year in the high-risk patients. The incidence rates of these clinical events in the non-high-risk patients were 3.3, 0.9, and 1.0%/patient-year, respectively.

Conclusions

Incidence rates of long-term bleeding and thromboembolism were higher in the high-risk patients than in the non-high-risk patients. However, the rates of these outcomes using the Japan-specific reduced dose were not so high. Furthermore, the balance between safety and effectiveness outcomes was within an acceptable range. The present study provides useful information for physicians to stratify high-risk patients using the reduced dose in daily clinical practice.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Bayer Yakuhin Ltd.

IκBα Nuclear Export Enables 4-1BB-Induced cRel Activation and IL-2 Production to Promote CD8 T Cell Immunity

Optimal CD8 T cell immunity is orchestrated by signaling events initiated by TCR recognition of peptide Ag in concert with signals from molecules such as CD28 and 4-1BB. The molecular mechanisms underlying the temporal and spatial signaling dynamics in CD8 T cells remain incompletely understood. In this study, we show that stimulation of naive CD8 T cells with agonistic CD3 and CD28 Abs, mimicking TCR and costimulatory signals, coordinately induces 4-1BB and cRel to enable elevated cytosolic cRel:IκBα complex formation and subsequent 4-1BB-induced IκBα degradation, sustained cRel activation, heightened IL-2 production and T cell expansion. Nfkbia^NES/NES CD8 T cells harboring a mutated IκBα nuclear export sequence abnormally accumulate inactive cRel:IκBα complexes in the nucleus following stimulation with agonistic anti-CD3 and anti-CD28 Abs, rendering them resistant to 4-1BB induced signaling and a disrupted chain of events necessary for efficient T cell expansion. Consequently, CD8 T cells in Nfkbia^NES/NES mice poorly expand during viral infection, and this can be overcome by exogenous IL-2 administration. Consistent with cell-based data, adoptive transfer experiments demonstrated that the antiviral CD8 T cell defect in Nfkbia^NES/NES mice was cell intrinsic. Thus, these results reveal that IκBα, via its unique nuclear export function, enables, rather than inhibits 4-1BB-induced cRel activation and IL-2 production to facilitate optimal CD8 T cell immunity.

IκBα deficiency imposes a fetal phenotype to intestinal stem cells

The intestinal epithelium is a paradigm of adult tissue in constant regeneration that is supported by intestinal stem cells (ISCs). The mechanisms regulating ISC homeostasis after injury are poorly understood. We previously demonstrated that IκBα, the main regulator of NF-κB, exerts alternative nuclear functions as cytokine sensor in a subset of PRC2-regulated genes. Here, we show that nuclear IκBα is present in the ISC compartment. Mice deficient for IκBα show altered intestinal cell differentiation with persistence of a fetal-like ISC phenotype, associated with aberrant PRC2 activity at specific loci. Moreover, IκBα-deficient intestinal cells produce morphologically aberrant organoids carrying a PRC2-dependent fetal-like transcriptional signature. DSS treatment, which induces acute damage in the colonic epithelium of mice, results in a temporary loss of nuclear P-IκBα and its subsequent accumulation in early CD44-positive regenerating areas. Importantly, IκBα-deficient mice show higher resistance to damage, likely due to the persistent fetal-like ISC phenotype. These results highlight intestinal IκBα as a chromatin sensor of inflammation in the ISC compartment.

Inflammation in nonischemic heart disease: initiation by cardiomyocyte CaMKII and NLRP3 inflammasome signaling

There is substantial evidence that chronic heart failure in humans and in animal models is associated with inflammation. Ischemic interventions such as myocardial infarction lead to necrotic cell death and release of damage associated molecular patterns, factors that signal cell damage and induce expression of proinflammatory chemokines and cytokines. It has recently become evident that nonischemic interventions are also associated with increases in inflammatory genes and immune cell accumulation in the heart and that these contribute to fibrosis and ventricular dysfunction. How proinflammatory responses are elicited in nonischemic heart disease which is not, at least initially, associated with cell death is a critical unanswered question. In this review we provide evidence supporting the hypothesis that cardiomyocytes are an initiating site of inflammatory gene expression in response to nonischemic stress. Furthermore we discuss the role of the multifunctional Ca2+/calmodulin-regulated kinase, CaMKIIδ, as a transducer of stress signals to nuclear factor-κB activation, expression of proinflammatory cytokines and chemokines, and priming and activation of the NOD-like pyrin domain-containing protein 3 (NLRP3) inflammasome in cardiomyocytes. We summarize recent evidence that subsequent macrophage recruitment, fibrosis and contractile dysfunction induced by angiotensin II infusion or transverse aortic constriction are ameliorated by blockade of CaMKII, of monocyte chemoattractant protein-1/C-C chemokine receptor type 2 signaling, or of NLRP3 inflammasome activation.

Bone Marrow Stromal Cells Transcriptionally Repress ESR1 but Cannot Overcome Constitutive ESR1 Mutant Activity

Estrogen receptor α (ER) is the target of endocrine therapies in ER-positive breast cancer (BC), but their therapeutic effectiveness diminishes with disease progression. Most metastatic BCs retain an ER-positive status, but ER expression levels are reduced. We asked how the bone tumor microenvironment (TME) regulates ER expression. We observed ESR1 mRNA and ER protein downregulation in BC cells treated with conditioned media (CM) from patient-derived, cancer-activated bone marrow stromal cells (BMSCs) and the BMSC cell line HS5. Decreases in ESR1 mRNA were attributed to decreases in nascent transcripts as well as decreased RNA polymerase II occupancy and H3K27Ac levels on the ESR1 promoter and/or distal enhancer (ENH1). Repression extended to neighboring genes of ESR1, including ARMT1 and SYNE1. Although ERK/MAPK signaling pathway can repress ER expression by other TME cell types, MAPK inhibition did not reverse decreases in ER expression by BMSC-CM. ESR1 mRNA and ER protein half-lives in MCF7 cells were unchanged by BMSC-CM treatment. Whereas ER phosphorylation was induced, ER activity was repressed by BMSC-CM as neither ER occupancy at known binding sites nor estrogen response element-luciferase activity was detected. BMSC-CM also repressed expression of ER target genes. In cells expressing the Y537S and D538G ESR1 mutations, BMSC-CM reduced ESR1, but expression of target genes PGR and TFF1 remained significantly elevated compared with that of control wild-type cells. These studies demonstrate that BMSCs can transcriptionally corepress ESR1 with neighboring genes and inhibit receptor activity, but the functional consequences of the BMSC TME can be limited by metastasis-associated ESR1 mutations.

Dissociation of mitochondrial HK-II elicits mitophagy and confers cardioprotection against ischemia

Preservation of mitochondrial integrity is critical for maintaining cellular homeostasis. Mitophagy is a mitochondria-specific type of autophagy which eliminates damaged mitochondria thereby contributing to mitochondrial quality control. Depolarization of the mitochondrial membrane potential is an established mechanism for inducing mitophagy, mediated through PINK1 stabilization and Parkin recruitment to mitochondria. Hexokinase-II (HK-II) which catalyzes the first step in glucose metabolism, also functions as a signaling molecule to regulate cell survival, and a significant fraction of cellular HK-II is associated with mitochondria (mitoHK-II). We demonstrate here that pharmacological interventions and adenoviral expression of a mitoHK-II dissociating peptide which reduce mitoHK-II levels lead to robust increases in mitochondrial Parkin and ubiquitination of mitochondrial proteins in cardiomyocytes and in a human glioblastoma cell line 1321N1, independent of mitochondrial membrane depolarization or PINK1 accumulation. MitoHK-II dissociation-induced mitophagy was demonstrated using Mito-Keima in cardiomyocytes and in 1321N1 cells. Subjecting cardiomyocytes or the in vivo heart to ischemia leads to modest dissociation of mitoHK-II. This response is potentiated by expression of the mitoHK-II dissociating peptide, which increases Parkin recruitment to mitochondria and, importantly, provides cardioprotection against ischemic stress. These results suggest that mitoHK-II dissociation is a physiologically relevant cellular event that is induced by ischemic stress, the enhancement of which protects against ischemic damage. The mechanism which underlies the effects of mitoHK-II dissociation can be attributed to the ability of Bcl2-associated athanogene 5 (BAG5), an inhibitor of Parkin, to localize to mitochondria and form a molecular complex with HK-II. Overexpression of BAG5 attenuates while knockdown of BAG5 sensitizes the effect of mitoHK-II dissociation on mitophagy. We suggest that HK-II, a glycolytic molecule, can function as a sensor for metabolic derangements at mitochondria to trigger mitophagy, and modulating the intracellular localization of HK-II could be a novel way of regulating mitophagy to prevent cell death induced by ischemic stress.

Inflammation and NLRP3 Inflammasome Activation Initiated in Response to Pressure Overload by Ca2+/Calmodulin-Dependent Protein Kinase II δ Signaling in Cardiomyocytes Are Essential for Adverse Cardiac Remodeling

BACKGROUND

Inflammation is associated with cardiac remodeling and heart failure, but how it is initiated in response to nonischemic interventions in the absence of cell death is not known. We tested the hypothesis that activation of Ca²⁺/calmodulin-dependent protein kinase II δ (CaMKIIδ) in cardiomyocytes (CMs) in response to pressure overload elicits inflammatory responses leading to adverse remodeling.

METHODS

Mice in which CaMKIIδ was selectively deleted from CMs (cardiac-specific knockout [CKO]) and floxed control mice were subjected to transverse aortic constriction (TAC). The effects of CM-specific CaMKIIδ deletion on inflammatory gene expression, inflammasome activation, macrophage accumulation, and fibrosis were assessed by quantitative polymerase chain reaction, histochemistry, and ventricular remodeling by echocardiography.

RESULTS

TAC induced increases in cardiac mRNA levels for proinflammatory chemokines and cytokines in ≤3 days, and these responses were significantly blunted when CM CaMKIIδ was deleted. Apoptotic and necrotic cell death were absent at this time. CMs isolated from TAC hearts mirrored these robust increases in gene expression, which were markedly attenuated in CKO. Priming and activation of the NOD-like receptor pyrin domain-containing protein 3 inflammasome, assessed by measuring interleukin-1β and NOD-like receptor pyrin domain-containing protein 3 mRNA levels, caspase-1 activity, and interleukin-18 cleavage, were increased at day 3 after TAC in control hearts and in CMs isolated from these hearts. These responses were dependent on CaMKIIδ and associated with activation of Nuclear Factor-kappa B and reactive oxygen species. Accumulation of macrophages observed at days 7 to 14 after TAC was diminished in CKO and, by blocking Monocyte Chemotactic Protein-1 signaling, deletion of CM Monocyte Chemotactic Protein-1 or inhibition of inflammasome activation. Fibrosis was also attenuated by these interventions and in the CKO heart. Ventricular dilation and contractile dysfunction observed at day 42 after TAC were diminished in the CKO. Inhibition of CaMKII, Nuclear Factor-kappa B, inflammasome, or Monocyte Chemotactic Protein-1 signaling in the first 1 or 2 weeks after TAC decreased remodeling, but inhibition of CaMKII after 2 weeks did not.

CONCLUSIONS

Activation of CaMKIIδ in response to pressure overload triggers inflammatory gene expression and activation of the NOD-like receptor pyrin domain-containing protein 3 inflammasome in CMs. These responses provide signals for macrophage recruitment, fibrosis, and myocardial dysfunction in the heart. Our work suggests the importance of targeting early inflammatory responses induced by CM CaMKIIδ signaling to prevent progression to heart failure.

CRISPR/Cas9-based editing of a sensitive transcriptional regulatory element to achieve cell type-specific knockdown of the NEMO scaffold protein

The use of alternative promoters for the cell type-specific expression of a given mRNA/protein is a common cell strategy. NEMO is a scaffold protein required for canonical NF-κB signaling. Transcription of the NEMO gene is primarily controlled by two promoters: one (promoter B) drives NEMO transcription in most cell types and the second (promoter D) is largely responsible for NEMO transcription in liver cells. Herein, we have used a CRISPR/Cas9-based approach to disrupt a core sequence element of promoter B, and this genetic editing essentially eliminates expression of NEMO mRNA and protein in 293T human kidney cells. By cell subcloning, we have isolated targeted 293T cell lines that express no detectable NEMO protein, have defined genomic alterations at promoter B, and do not support activation of canonical NF-κB signaling in response to treatment with tumor necrosis factor. Nevertheless, non-canonical NF-κB signaling is intact in these NEMO-deficient cells. Expression of ectopic wild-type NEMO, but not certain human NEMO disease mutants, in the edited cells restores downstream NF-κB signaling in response to tumor necrosis factor. Targeting of the promoter B element does not substantially reduce NEMO expression (from promoter D) in the human SNU-423 liver cancer cell line. Thus, we have created a strategy for selectively eliminating cell type-specific expression from an alternative promoter and have generated 293T cell lines with a functional knockout of NEMO. The implications of these findings for further studies and for therapeutic approaches to target canonical NF-κB signaling are discussed.

Identification of the Bleeding Point in Hemorrhagic Moyamoya Disease Using Fusion Images of Susceptibility-Weighted Imaging and Time-of-Flight MRA

BACKGROUND AND PURPOSE

The location of intracerebral hemorrhage in Moyamoya disease is a prognostic factor for rebleeding and the degree of preventive effects obtainable with bypass surgery. We evaluated whether the bleeding point and responsible vessel were detectable using fusion images of SWI and time-of-flight MRA performed during chronic-phase hemorrhage.

MATERIALS AND METHODS

We retrospectively enrolled 42 patients with hemorrhagic Moyamoya disease (48 hemorrhagic events). Fusion images of SWI and MRA were made using workstations, and we defined the bleeding point as the point at which the signal of an abnormally extended artery on MRA overlapped the hypointense area on SWI. Two independent raters identified the bleeding point, and classified the location and responsible vessels.

RESULTS

The bleeding point was detectable at a frequency of 79.2% by rater 1. Agreement for the presence of a bleeding point was high (interrater κ = 0.83; 95% CI, 0.65-1; intrarater κ = 0.86; 95% CI, 0.68-1). The frequency of a periventricular location of the bleeding point was 65.8% by rater 1, and agreement on the location was again high (interrater κ = 0.92; 95% CI, 0.82-1; intrarater κ = 0.85; 95% CI, 0.72-0.99). The choroidal artery was the most frequent responsible vessel (57.9% by rater 1), and agreement on the responsible vessel was high (interrater κ = 0.84; 95% CI, 0.69-1; intrarater κ = 0.90; 95% CI, 0.78-1).

CONCLUSIONS

Detection of the bleeding point in hemorrhagic Moyamoya disease using SWI and MRA fusion images offers highly reproducible results.