Initiation of warfarin is associated with decreased mortality in patients with infective endocarditis: A population-based cohort study.

The use of warfarin to prevent thromboembolism in patients with infective endocarditis (IE) remains controversial due to potentially increased bleeding risks. Population-based retrospective cohort study. Patients aged 18 or older and diagnosed with IE in Hong Kong between January 1st, 1997 and August 31st, 2020 were included. Patients with use of any anticoagulant 30 days before IE diagnosis were excluded. Patients initiated on warfarin within 14 days of IE diagnosis and patients without warfarin use were matched for baseline characteristics using 1:1 propensity score matching. Warfarin use within 14 days of IE diagnosis. Patients were followed up to 90 days for the outcomes of ischemic stroke, all-cause mortality, intracranial hemorrhage, and gastrointestinal bleeding. Cox regression was used to determine hazard ratios (HRs) [95 % confidence intervals (CIs)] between treatment groups. Fine-Gray competing risk regression with all-cause mortality as the competing event was performed as a sensitivity analysis. In addition to 90-day analyses, landmark analyses were performed at 30 days of follow-up. The matched cohort consisted of 675 warfarin users (57.0 % male, age 59 ± 16 years) and 675 warfarin non-users (53.5 % male, age 61 ± 19 years). Warfarin users had a 50 % decreased 90-day risk in all-cause mortality (HR:0.50 [0.39-0.65]), without significantly different 90-day risks of ischemic stroke (HR:1.04 [0.70-1.53]), intracranial hemorrhage (HR:1.25 [0.77-2.04]), and gastrointestinal bleeding (HR:1.04 [0.60-1.78]). Thirty-day landmark analysis showed similar results. Competing risk regression showed significantly higher 30-day cumulative incidence of intracranial hemorrhage in warfarin users (sub-HR:3.34 [1.34-8.31]), but not at 90-day (sub-HR:1.63 [0.95-2.81]). Results from Fine-Gray regression were otherwise congruent with those from Cox regression. Warfarin initiated within 14 days of IE diagnosis was associated with significantly decreased risks of mortality but higher risks of intracranial hemorrhage, with similar risks of ischemic stroke and gastrointestinal bleeding, compared with non-use of warfarin with 14 days of IE diagnosis. Question: Is warfarin, initiated within 14 days of a diagnosis of infective endocarditis (IE), efficacious and safe? In this propensity score-matched, population-based, prospective cohort study from Hong Kong, warfarin use within 14 days of IE diagnosis was associated with a 50 % decrease in the risk of all-cause mortality, albeit with higher risk of intracranial hemorrhage, and without significant differences in the risk of ischaemic stroke and gastrointestinal bleeding. Meaning: In patients with IE, warfarin use within 14 days of diagnosis may have mortality benefits, despite increased risks of intracranial hemorrhage. [Abstract copyright: Copyright © 2023. Published by Elsevier Ltd.

High visit-to-visit cholesterol variability predicts heart failure and adverse cardiovascular events: a population-based cohort study

Dyslipidaemia is associated with elevated cardiovascular risks, with the INTERHEART study observing a tripling of myocardial infarction (MI) risk in patients with dyslipidaemia.1 Most studies focused on mean levels or point estimates of low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), despite well-known visit-to-visit variability.2 Visit-to-visit cholesterol variability, reflecting fluctuations in cholesterol levels between visits, is prognostic for some adverse cardiovascular outcomes such as cardiac arrhythmias and mortality.3,4 Nonetheless, associations between cholesterol variability and heart failure (HF) remain unclear. This study therefore investigated the associations between LDL-C and HDL-C variabilities and the risk of new-onset HF and major adverse cardiovascular outcomes

Targeting of Slc25a21 is associated with orofacial defects and otitis media due to disrupted expression of a neighbouring gene.

Homozygosity for Slc25a21(tm1a(KOMP)Wtsi) results in mice exhibiting orofacial abnormalities, alterations in carpal and rugae structures, hearing impairment and inflammation in the middle ear. In humans it has been hypothesised that the 2-oxoadipate mitochondrial carrier coded by SLC25A21 may be involved in the disease 2-oxoadipate acidaemia. Unexpectedly, no 2-oxoadipate acidaemia-like symptoms were observed in animals homozygous for Slc25a21(tm1a(KOMP)Wtsi) despite confirmation that this allele reduces Slc25a21 expression by 71.3%. To study the complete knockout, an allelic series was generated using the loxP and FRT sites typical of a Knockout Mouse Project allele. After removal of the critical exon and neomycin selection cassette, Slc25a21 knockout mice homozygous for the Slc25a21(tm1b(KOMP)Wtsi) and Slc25a21(tm1d(KOMP)Wtsi) alleles were phenotypically indistinguishable from wild-type. This led us to explore the genomic environment of Slc25a21 and to discover that expression of Pax9, located 3' of the target gene, was reduced in homozygous Slc25a21(tm1a(KOMP)Wtsi) mice. We hypothesize that the presence of the selection cassette is the cause of the down regulation of Pax9 observed. The phenotypes we observed in homozygous Slc25a21(tm1a(KOMP)Wtsi) mice were broadly consistent with a hypomorphic Pax9 allele with the exception of otitis media and hearing impairment which may be a novel consequence of Pax9 down regulation. We explore the ramifications associated with this particular targeted mutation and emphasise the need to interpret phenotypes taking into consideration all potential underlying genetic mechanisms

Predictive value of neutrophil-to-lymphocyte ratio for atrial fibrillation and stroke in type 2 diabetes mellitus: The Hong Kong Diabetes Study

Neutrophil-to-lymphocyte ratio (NLR) is a routinely available biomarker that reflects systemic inflammation. The study evaluated the predictive value of NLR for ischemic stroke and atrial fibrillation (AF) in patients with type 2 diabetes mellitus. This was a population-based cohort study of patients with type 2 diabetes mellitus and complete blood count tests at baseline between 1 January 1st, 2009, and 31 December, 2009, at government-funded hospitals/clinics in Hong Kong. Follow-up was until 31 December, 2019, or death. A total of 85,351 patients (age = 67.6 ± 13.2 years old, male = 48.8%, follow-up = 3101 ± 1441 days) were included. Univariable Cox regression found that increased NLR at quartiles 2, 3 and 4 was significantly associated with higher risks of new-onset ischemic stroke (hazard ratio [HR]: 1.28 [1.20-1.37], p < .001, HR: 1.41 [1.32-1.51], p < .001 and HR: 1.38 [1.29-1.47], p < .001) and AF (HR: 1.09 [1.02-1.17], p < .015; HR: 1.28 [1.20-1.37], p < .001; HR: 1.39 [1.31-1.49], p < .001) compared to quartile 1. On multivariable analysis, NLR remained a significant predictor of ischemic stroke risk for quartiles 2 and 3 (quartile 2: HR: 1.14 [1.05, 1.22], p = .001; quartile 3: HR: 1.14 [1.06, 1.23], p < .001) but not quartile 4 (HR: 1.08 [0.994, 1.17], p = .070). NLR was not predictive of AF after adjusting for confounders (quartile 2: HR: 0.966 [0.874, 1.07], p = .499; quartile 3: HR: 0.978 [0.884, 1.08], p = .661; quartile 4: HR: 1.05 [0.935, 1.16], p = .462). NLR is a significant predictor of new-onset ischaemic stroke after adjusting for significant confounders in Chinese type 2 diabetes patients

A Novel murine model identifies cooperating mutations and therapeutic targets critical for chronic myeloid leukemia progression

The introduction of highly selective ABL-tyrosine kinase inhibitors (TKIs) has revolutionized therapy for chronic myeloid leukemia (CML). However, TKIs are only efficacious in the chronic phase of the disease and effective therapies for TKI-refractory CML, or after progression to blast crisis (BC), are lacking. Whereas the chronic phase of CML is dependent on BCR-ABL, additional mutations are required for progression to BC. However, the identity of these mutations and the pathways they affect are poorly understood, hampering our ability to identify therapeutic targets and improve outcomes. Here, we describe a novel mouse model that allows identification of mechanisms of BC progression in an unbiased and tractable manner, using transposon-based insertional mutagenesis on the background of chronic phase CML. Our BC model is the first to faithfully recapitulate the phenotype, cellular and molecular biology of human CML progression. We report a heterogeneous and unique pattern of insertions identifying known and novel candidate genes and demonstrate that these pathways drive disease progression and provide potential targets for novel therapeutic strategies. Our model greatly informs the biology of CML progression and provides a potent resource for the development of candidate therapies to improve the dismal outcomes in this highly aggressive disease.Work in the Huntly laboratory is funded by CRUK, The European Research Council (ERC), Leukaemia Lymphoma Research, the Kay Kendall Leukaemia Fund, Wellcome Trust, the Medical Research Council (UK), the Leukemia Lymphoma Society America and the Cambridge NIHR Biomedical Research centre. David Adams is funded by Cancer Research UK and Wellcome Trust. Steffen Koschmieder has received funding from Deutsche José Carreras Leukämie-Stiftung (DJCLS; grant 10/23).This is the final published version. It first appeared at http://dx.doi.org/10.1084/jem.2014166

Genome-Wide Analysis of Transcriptional Reprogramming in Mouse Models of Acute Myeloid Leukaemia

Acute leukaemias are commonly caused by mutations that corrupt the transcriptional circuitry of haematopoietic stem/progenitor cells. However, the mechanisms underlying large-scale transcriptional reprogramming remain largely unknown. Here we investigated transcriptional reprogramming at genome-scale in mouse retroviral transplant models of acute myeloid leukaemia (AML) using both gene-expression profiling and ChIP-sequencing. We identified several thousand candidate regulatory regions with altered levels of histone acetylation that were characterised by differential distribution of consensus motifs for key haematopoietic transcription factors including Gata2, Gfi1 and Sfpi1/Pu.1. In particular, downregulation of Gata2 expression was mirrored by abundant GATA motifs in regions of reduced histone acetylation suggesting an important role in leukaemogenic transcriptional reprogramming. Forced re-expression of Gata2 was not compatible with sustained growth of leukaemic cells thus suggesting a previously unrecognised role for Gata2 in downregulation during the development of AML. Additionally, large scale human AML datasets revealed significantly higher expression of GATA2 in CD34+ cells from healthy controls compared with AML blast cells. The integrated genome-scale analysis applied in this study represents a valuable and widely applicable approach to study the transcriptional control of both normal and aberrant haematopoiesis and to identify critical factors responsible for transcriptional reprogramming in human cancer

Early loss of Crebbp confers malignant stem cell properties on lymphoid progenitors.

Loss-of-function mutations of cyclic-AMP response element binding protein, binding protein (CREBBP) are prevalent in lymphoid malignancies. However, the tumour suppressor functions of CREBBP remain unclear. We demonstrate that loss of Crebbp in murine haematopoietic stem and progenitor cells (HSPCs) leads to increased development of B-cell lymphomas. This is preceded by accumulation of hyperproliferative lymphoid progenitors with a defective DNA damage response (DDR) due to a failure to acetylate p53. We identify a premalignant lymphoma stem cell population with decreased H3K27ac, which undergoes transcriptional and genetic evolution due to the altered DDR, resulting in lymphomagenesis. Importantly, when Crebbp is lost later in lymphopoiesis, cellular abnormalities are lost and tumour generation is attenuated. We also document that CREBBP mutations may occur in HSPCs from patients with CREBBP-mutated lymphoma. These data suggest that earlier loss of Crebbp is advantageous for lymphoid transformation and inform the cellular origins and subsequent evolution of lymphoid malignancies

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data