A case of disseminated cryptococcosis with abdominal involvement due to Cryptococcus neoformans species complex in a Ragdoll cat and false-negative cryptococcal antigen lateral flow tests due to the postzone phenomenon

Although cryptococcosis is the most common systemic fungal disease of cats, abdominal involvement is rarely reported. The pathogenesis of cryptococcosis usually involves sinonasal colonisation, followed by tissue invasion and sinonasal infection, with possible subsequent spread to the lungs and/or direct extension into the central nervous system (CNS), for example, via the cribriform plate. Further haematogenous spread can occur to any tissue, including skin and the CNS. This report describes a case of disseminated cryptococcosis due to Cryptococcus neoformans species complex in a 13-year-old cat, the fourth documented Australian feline case with abdominal involvement. The cat presented with a chronic history of upper respiratory disease that progressed to severe lethargy and anorexia. An autopsy revealed striking peritonitis with multifocal abdominal involvement affecting the liver, spleen, adrenal glands, kidneys, pancreas and mesentery. Cryptococcal organisms were also observed in organs within the thoracic cavity, sinonasal tissues and the CNS. Testing of abdominal fluid and serum for cryptococcal antigen using a commercially available lateral flow assay using neat fluid specimen initially tested false-negative. However, after dilution of the sample to 1:64, a positive result was obtained, confirming a postzone phenomenon. Taken together, the collective findings were indicative of widely disseminated cryptococcosis due to Cryptococcus neoformans with atypical involvement of the abdominal cavity.

Proteomics of mouse brain endothelium uncovers dysregulation of vesicular transport pathways during aging

Age-related decline in brain endothelial cell (BEC) function contributes critically to neurological disease. Comprehensive atlases of the BEC transcriptome have become available, but results from proteomic profiling are lacking. To gain insights into endothelial pathways affected by aging, we developed a magnetic-activated cell sorting-based mouse BEC enrichment protocol compatible with proteomics and resolved the profiles of protein abundance changes during aging. Unsupervised cluster analysis revealed a segregation of age-related protein dynamics with biological functions, including a downregulation of vesicle-mediated transport. We found a dysregulation of key regulators of endocytosis and receptor recycling (most prominently Arf6), macropinocytosis and lysosomal degradation. In gene deletion and overexpression experiments, Arf6 affected endocytosis pathways in endothelial cells. Our approach uncovered changes not picked up by transcriptomic studies, such as accumulation of vesicle cargo and receptor ligands, including Apoe. Proteomic analysis of BECs from Apoe-deficient mice revealed a signature of accelerated aging. Our findings provide a resource for analysing BEC function during aging.

AI implementation in the UK landscape: Knowledge of AI governance, perceived challenges and opportunities, and ways forward for radiographers

INTRODUCTION

Despite the rapid increase of AI-enabled applications deployed in clinical practice, many challenges exist around AI implementation, including the clarity of governance frameworks, usability of validation of AI models, and customisation of training for radiographers. This study aimed to explore the perceptions of diagnostic and therapeutic radiographers, with existing theoretical and/or practical knowledge of AI, on issues of relevance to the field, such as AI implementation, including knowledge of AI governance and procurement, perceptions about enablers and challenges and future priorities for AI adoption.

METHODS

An online survey was designed and distributed to UK-based qualified radiographers who work in medical imaging and/or radiotherapy and have some previous theoretical and/or practical knowledge of working with AI. Participants were recruited through the researchers' professional networks on social media with support from the AI advisory group of the Society and College of Radiographers. Survey questions related to AI training/education, knowledge of AI governance frameworks, data privacy procedures, AI implementation considerations, and priorities for AI adoption. Descriptive statistics were employed to analyse the data, and chi-square tests were used to explore significant relationships between variables.

RESULTS

In total, 88 valid responses were received. Most radiographers (56.6 %) had not received any AI-related training. Also, although approximately 63 % of them used an evaluation framework to assess AI models' performance before implementation, many (36.9 %) were still unsure about suitable evaluation methods. Radiographers requested clearer guidance on AI governance, ample time to implement AI in their practice safely, adequate funding, effective leadership, and targeted support from AI champions. AI training, robust governance frameworks, and patient and public involvement were seen as priorities for the successful implementation of AI by radiographers.

CONCLUSION

AI implementation is progressing within radiography, but without customised training, clearer governance, key stakeholder engagement and suitable new roles created, it will be hard to harness its benefits and minimise related risks.

IMPLICATIONS FOR PRACTICE

The results of this study highlight some of the priorities and challenges for radiographers in relation to AI adoption, namely the need for developing robust AI governance frameworks and providing optimal AI training.

Proteogenomic Data Integration Reveals CXCL10 as a Potentially Downstream Causal Mediator for IL-6 Signaling on Atherosclerosis

BACKGROUND

Genetic and experimental studies support a causal involvement of IL-6 (interleukin-6) signaling in atheroprogression. Although trials targeting IL-6 signaling are underway, any benefits must be balanced against an impaired host immune response. Dissecting the mechanisms that mediate the effects of IL-6 signaling on atherosclerosis could offer insights about novel drug targets with more specific effects.

METHODS

Leveraging data from 522 681 individuals, we constructed a genetic instrument of 26 variants in the gene encoding the IL-6R (IL-6 receptor) that proxied for pharmacological IL-6R inhibition. Using Mendelian randomization, we assessed its effects on 3281 plasma proteins quantified with an aptamer-based assay in the INTERVAL cohort (n=3301). Using mediation Mendelian randomization, we explored proteomic mediators of the effects of genetically proxied IL-6 signaling on coronary artery disease, large artery atherosclerotic stroke, and peripheral artery disease. For significant mediators, we tested associations of their circulating levels with incident cardiovascular events in a population-based study (n=1704) and explored the histological, transcriptomic, and cellular phenotypes correlated with their expression levels in samples from human atherosclerotic lesions.

RESULTS

We found significant effects of genetically proxied IL-6 signaling on 70 circulating proteins involved in cytokine production/regulation and immune cell recruitment/differentiation, which correlated with the proteomic effects of pharmacological IL-6R inhibition in a clinical trial. Among the 70 significant proteins, genetically proxied circulating levels of CXCL10 (C-X-C motif chemokine ligand 10) were associated with risk of coronary artery disease, large artery atherosclerotic stroke, and peripheral artery disease, with up to 67% of the effects of genetically downregulated IL-6 signaling on these end points mediated by decreases in CXCL10. Higher midlife circulating CXCL10 levels were associated with a larger number of cardiovascular events over 20 years, whereas higher CXCL10 expression in human atherosclerotic lesions correlated with a larger lipid core and a transcriptomic profile reflecting immune cell infiltration, adaptive immune system activation, and cytokine signaling.

CONCLUSIONS

Integrating multiomics data, we found a proteomic signature of IL-6 signaling activation and mediators of its effects on cardiovascular disease. Our analyses suggest the interferon-γ-inducible chemokine CXCL10 to be a potentially causal mediator for atherosclerosis in 3 vascular compartments and, as such, could serve as a promising drug target for atheroprotection.

Deep Resequencing of the 1q22 Locus in Non-Lobar Intracerebral Hemorrhage

OBJECTIVE

Genome-wide association studies have identified 1q22 as a susceptibility locus for cerebral small vessel diseases, including non-lobar intracerebral hemorrhage (ICH) and lacunar stroke. In the present study, we performed targeted high-depth sequencing of 1q22 in ICH cases and controls to further characterize this locus and prioritize potential causal mechanisms, which remain unknown.

METHODS

A total of 95,000 base pairs spanning 1q22, including SEMA4A, SLC25A44, and PMF1/PMF1-BGLAP were sequenced in 1,055 spontaneous ICH cases (534 lobar and 521 non-lobar) and 1,078 controls. Firth regression and Rare Variant Influential Filtering Tool analysis were used to analyze common and rare variants, respectively. Chromatin interaction analyses were performed using Hi-C, chromatin immunoprecipitation followed by sequencing, and chromatin interaction analysis with paired-end tag databases. Multivariable Mendelian randomization assessed whether alterations in gene-specific expression relative to regionally co-expressed genes at 1q22 could be causally related to ICH risk.

RESULTS

Common and rare variant analyses prioritized variants in SEMA4A 5'-UTR and PMF1 intronic regions, overlapping with active promoter and enhancer regions based on ENCODE annotation. Hi-C data analysis determined that 1q22 is spatially organized in a single chromatin loop, and that the genes therein belong to the same topologically associating domain. Chromatin immunoprecipitation followed by sequencing and chromatin interaction analysis with paired-end tag data analysis highlighted the presence of long-range interactions between the SEMA4A-promoter and PMF1-enhancer regions prioritized by association testing. Multivariable Mendelian randomization analyses demonstrated that PMF1 overexpression could be causally related to non-lobar ICH risk.

INTERPRETATION

Altered promoter-enhancer interactions leading to PMF1 overexpression, potentially dysregulating polyamine catabolism, could explain demonstrated associations with non-lobar ICH risk at 1q22, offering a potential new target for prevention of ICH and cerebral small vessel disease. ANN NEUROL 2024;95:325-337.

Genetically proxied HTRA1 protease activity and circulating levels independently predict risk of ischemic stroke and coronary artery disease

HTRA1 has emerged as a major risk gene for stroke and cerebral small vessel disease with both rare and common variants contributing to disease risk. However, the precise mechanisms mediating this risk remain largely unknown as does the full spectrum of phenotypes associated with genetic variation in HTRA1 in the general population. Using a family-history informed approach, we first show that rare variants in HTRA1 are linked to ischemic stroke in 425,338 European individuals from the UK Biobank with replication in 143,149 individuals from the Biobank Japan. Integrating data from biochemical experiments on 76 mutations occurring in the UK Biobank, we next show that rare variants causing loss of protease function in vitro associate with ischemic stroke, coronary artery disease, and skeletal traits. In addition, a common causal variant (rs2672592) modulating circulating HTRA1 mRNA and protein levels enhances the risk of ischemic stroke, small vessel stroke, and coronary artery disease while lowering the risk of migraine and age-related macular dystrophy in GWAS and UK Biobank data from > 2,000,000 individuals. There was no evidence of an interaction between genetically proxied HTRA1 activity and levels. Our findings demonstrate a central role of HTRA1 for human disease including stroke and coronary artery disease and identify two independent mechanisms that might qualify as targets for future therapeutic interventions.

A severe case of disseminated cryptococcosis in a young French bulldog living in South-East Queensland caused by Cryptococcus gattii VGII

BACKGROUND

Cryptococcus is one of the most common systemic mycosis worldwide, infecting young adults of the large to giant breed dogs. Infection is commonly acquired from the environment via the sinonasal cavity as the main portal of entry. It either remains there, or spreads to the central nervous system (CNS) and the eye (optic nerve and retina) by penetration of the cribriform plate, or haematogenously to other viscera. Lung involvement is uncommon in cats and dogs in contrast to human and equine patients. Whilst there is a wide genetic diversity amongst Cryptococcus neoformans and Cryptococcus gattii isolates along the West Coast and Northern parts of Australia, the molecular diversity of C. gatti is considered very low on the East Coast of Australia, with a huge preponderance of VGI cases. We report on a young small breed brachycephalic dog that presented with extreme gastrointestinal and respiratory signs, but no CNS involvement. It is the first reported case of C. gattii VGII genotype in a companion animal from Queensland.

CASE REPORT

A 9-month old female entire French Bulldog presented initially for diarrhoea. Clinical progression was accompanied by the development of respiratory signs, so the patient was referred to a 24 h care facility. Following hospitalisation, the patient became hypoxemic requiring mechanical ventilation. A bronchoalveolar lavage performed antemortem confirmed abundant Cryptococcal spp. Further culturing and genotyping identified the species as Cryptococcus gattii VGII. Post-mortem findings indicated gross gastrointestinal and mesenteric involvement, with possible dissemination to the local mesenteric lymph node and lungs.

CONCLUSION

This case describes a rare example of a Cryptococcus spp suspected of disseminating from the gastrointestinal tract to the lungs, without involvement of the CNS. The observation of this finding in a small brachycephalic breed is unusual, and the finding of genotype VGII on the East Coast of Queensland is extremely unusual as there is no prior travel history of the dog or owners. The presence of a miliary lung pattern with primary gastrointestinal disease in a small breed dog warrants adding cryptococcosis to the differential diagnosis.

Mixed-reality technology for clinical communication: objective assessment of the HoloLens 2 as a clinical communication device in a simulated on-call scenario

OBJECTIVE

Specialty on-call clinicians cover large areas and complex workloads. This study aimed to assess clinical communication using the mixed-reality HoloLens 2 device within a simulated on-call scenario.

METHOD

This study was structured as a randomised, within-participant, controlled study. Thirty ENT trainees used either the HoloLens 2 or a traditional telephone to communicate a clinical case to a consultant. The quality of the clinical communication was scored objectively and subjectively.

RESULTS

Clinical communication using the HoloLens 2 scored statistically higher than telephone (n = 30) (11.9 of 15 vs 10.2 of 15; p = 0.001). Subjectively, consultants judged more communication episodes to be inadequate when using the telephone (7 of 30) versus the HoloLens 2 (0 of 30) (p = 0.01). Qualitative feedback indicates that the HoloLens 2 was easy to use and would add value during an on-call scenario with remote consultant supervision.

CONCLUSION

This study demonstrated the benefit that mixed-reality devices, such as the HoloLens 2 can bring to clinical communication through increasing the accuracy of communication and confidence of the users.

Carriers of rare damaging CCR2 genetic variants are at lower risk of atherosclerotic disease

Background

The CCL2/CCR2 axis governs monocyte trafficking and recruitment to atherosclerotic lesions. Human genetic analyses and population-based studies support an association between circulating CCL2 levels and atherosclerosis. Still, it remains unknown whether pharmacological targeting of CCR2, the main CCL2 receptor, would provide protection against human atherosclerotic disease.

Methods

In whole-exome sequencing data from 454,775 UK Biobank participants (40-69 years), we identified predicted loss-of-function (LoF) or damaging missense (REVEL score >0.5) variants within the CCR2 gene. We prioritized variants associated with lower monocyte count (p<0.05) and tested associations with vascular risk factors and risk of atherosclerotic disease over a mean follow-up of 14 years. The results were replicated in a pooled cohort of three independent datasets (TOPMed, deCODE and Penn Medicine BioBank; total n=441,445) and the effect of the most frequent damaging variant was experimentally validated.

Results

A total of 45 predicted LoF or damaging missense variants were identified in the CCR2 gene, 4 of which were also significantly associated with lower monocyte count, but not with other white blood cell counts. Heterozygous carriers of these variants were at a lower risk of a combined atherosclerosis outcome, showed a lower burden of atherosclerosis across four vascular beds, and were at a lower lifetime risk of coronary artery disease and myocardial infarction. There was no evidence of association with vascular risk factors including LDL-cholesterol, blood pressure, glycemic status, or C-reactive protein. Using a cAMP assay, we found that cells transfected with the most frequent CCR2 damaging variant (3:46358273:T:A, M249K, 547 carriers, frequency: 0.14%) show a decrease in signaling in response to CCL2. The associations of the M249K variant with myocardial infarction were consistent across cohorts (ORUKB: 0.62 95%CI: 0.39-0.96; ORexternal: 0.64 95%CI: 0.34-1.19; ORpooled: 0.64 95%CI: 0.450.90). In a phenome-wide association study, we found no evidence for higher risk of common infections or mortality among carriers of damaging CCR2 variants.

Conclusions

Heterozygous carriers of damaging CCR2 variants have a lower burden of atherosclerosis and lower lifetime risk of myocardial infarction. In conjunction with previous evidence from experimental and epidemiological studies, our findings highlight the translational potential of CCR2-targeting as an atheroprotective approach.

Deep resequencing of the 1q22 locus in non-lobar intracerebral hemorrhage

Objective

Genome-wide association studies have identified 1q22 as a susceptibility locus for cerebral small vessel diseases (CSVDs), including non-lobar intracerebral hemorrhage (ICH) and lacunar stroke. In the present study we performed targeted high-depth sequencing of 1q22 in ICH cases and controls to further characterize this locus and prioritize potential causal mechanisms, which remain unknown.

Methods

95,000 base pairs spanning 1q22 , including SEMA4A, SLC25A44 and PMF1 / PMF1-BGLAP were sequenced in 1,055 spontaneous ICH cases (534 lobar and 521 non-lobar) and 1,078 controls. Firth regression and RIFT analysis were used to analyze common and rare variants, respectively. Chromatin interaction analyses were performed using Hi-C, ChIP-Seq and ChIA-PET databases. Multivariable Mendelian randomization (MVMR) assessed whether alterations in gene-specific expression relative to regionally co-expressed genes at 1q22 could be causally related to ICH risk.

Results

Common and rare variant analyses prioritized variants in SEMA4A 5'-UTR and PMF1 intronic regions, overlapping with active promoter and enhancer regions based on ENCODE annotation. Hi-C data analysis determined that 1q22 is spatially organized in a single chromatin loop and that the genes therein belong to the same Topologically Associating Domain. ChIP-Seq and ChIA-PET data analysis highlighted the presence of long-range interactions between the SEMA4A -promoter and PMF1 -enhancer regions prioritized by association testing. MVMR analyses demonstrated that PMF1 overexpression could be causally related to non-lobar ICH risk.

Interpretation

Altered promoter-enhancer interactions leading to PMF1 overexpression, potentially dysregulating polyamine catabolism, could explain demonstrated associations with non-lobar ICH risk at 1q22 , offering a potential new target for prevention of ICH and CSVD.

A Genomic Risk Score Identifies Individuals at High Risk for Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) has an estimated heritability of 29%. We developed a genomic risk score for ICH and determined its predictive power in comparison to standard clinical risk factors.

METHODS

We combined genome-wide association data from individuals of European ancestry for ICH and related traits in a meta-genomic risk score ([metaGRS]; 2.6 million variants). We tested associations with ICH and its predictive performance in addition to clinical risk factors in a held-out validation dataset (842 cases and 796 controls). We tested associations with risk of incident ICH in the population-based UK Biobank cohort (486 784 individuals, 1526 events, median follow-up 11.3 years).

RESULTS

One SD increment in the metaGRS was significantly associated with 31% higher odds for ICH (95% CI, 1.16-1.48) in age-, sex- and clinical risk factor-adjusted models. The metaGRS identified individuals with almost 5-fold higher odds for ICH in the top score percentile (odds ratio, 4.83 [95% CI, 1.56-21.2]). Predictive models for ICH incorporating the metaGRS in addition to clinical predictors showed superior performance compared to the clinical risk factors alone (c-index, 0.695 versus 0.686). The metaGRS showed similar associations for lobar and nonlobar ICH, independent of the known APOE risk locus for lobar ICH. In the UK Biobank, the metaGRS was associated with higher risk of incident ICH (hazard ratio, 1.15 [95% CI, 1.09-1.21]). The associations were significant within both a relatively high-risk population of antithrombotic medications users, as well as among a relatively low-risk population with a good control of vascular risk factors and no use of anticoagulants.

CONCLUSIONS

We developed and validated a genomic risk score that predicts lifetime risk of ICH beyond established clinical risk factors among individuals of European ancestry. Whether implementation of the score in risk prognostication models for high-risk populations, such as patients under antithrombotic treatment, could improve clinical decision making should be explored in future studies.

Proteogenomic integration reveals CXCL10 as a potentially downstream causal mediator for IL-6 signaling on atherosclerosis

Background

Genetic and experimental studies support a causal involvement of interleukin-6 (IL-6) signaling in atheroprogression. While trials targeting IL-6 signaling are underway, any benefits must be balanced against an impaired host immune response. Dissecting the mechanisms that mediate the effects of IL-6 signaling on atherosclerosis could offer insights about novel drug targets with more specific effects.

Methods

Leveraging data from 522,681 individuals, we constructed a genetic instrument of 26 variants in the gene encoding the IL-6 receptor (IL-6R) that proxied for pharmacological IL-6R inhibition. Using Mendelian randomization (MR), we assessed its effects on 3,281 plasma proteins quantified with an aptamer-based assay in the INTERVAL cohort (n=3,301). Using mediation MR, we explored proteomic mediators of the effects of genetically proxied IL-6 signaling on coronary artery disease (CAD), large artery atherosclerotic stroke (LAAS), and peripheral artery disease (PAD). For significant mediators, we tested associations of their circulating levels with incident cardiovascular events in a population-based study (n=1,704) and explored the histological, transcriptomic, and cellular phenotypes correlated with their expression levels in samples from human atherosclerotic lesions.

Results

We found significant effects of genetically proxied IL-6 signaling on 70 circulating proteins involved in cytokine production/regulation and immune cell recruitment/differentiation, which correlated with the proteomic effects of pharmacological IL-6R inhibition in a clinical trial. Among the 70 significant proteins, genetically proxied circulating levels of CXCL10 were associated with risk of CAD, LAAS, and PAD with up to 67% of the effects of genetically downregulated IL-6 signaling on these endpoints mediated by decreases in CXCL10. Higher midlife circulating CXCL10 levels were associated with a larger number of cardiovascular events over 20 years, whereas higher CXCL10 expression in human atherosclerotic lesions correlated with a larger lipid core and a transcriptomic profile reflecting immune cell infiltration, adaptive immune system activation, and cytokine signaling.

Conclusions

Integrating multiomics data, we found a proteomic signature of IL-6 signaling activation and mediators of its effects on cardiovascular disease. Our analyses suggest the interferon-γ-inducible chemokine CXCL10 to be a potentially causal mediator for atherosclerosis in three vascular compartments and as such could serve as a promising drug target for atheroprotection.

Acute kidney injury in 18 cats after subcutaneous meloxicam and an update on non-steroidal anti-inflammatory drug usage in feline patients in Australia

OBJECTIVES

Acute kidney injury (AKI) is a well-known but poorly documented adverse effect of non-steroidal anti-inflammatory drugs (NSAIDs) in cats. We aimed to describe instances of NSAID-associated AKI in cats and survey Australian veterinarians on NSAID use in acute settings.

METHODS

Medical records of cats that developed an AKI subsequent to the administration of meloxicam were obtained by searching the databases of seven practices in Queensland, as well as by contemporaneously contacting select veterinary colleagues of the authors in both general and specialist small animal practice. An online questionnaire was created for the survey, and the URL distributed to Australian practitioners.

RESULTS

A total of 18 cases were retrieved, all of which received injectable meloxicam. The indication(s) for its use and the dosage prescribed were within the manufacturer's recommendations for Australian veterinarians. The majority of cases (13/18 cats) received the label dose of 0.3 mg/kg subcutaneously (SC) on the day of the procedure. In 12/18 cats, the injection was given in association with general anaesthesia or sedation. Fourteen cats survived to hospital discharge. Of 187 survey respondees, 89% routinely administered NSAIDs for surgery-related analgesia, with 98% prescribing meloxicam and 84% of these giving it SC. Ninety percent of respondees routinely administered NSAIDs for non-surgical-related analgesia, with 99% prescribing meloxicam and 35% of those giving it SC.

CONCLUSIONS AND RELEVANCE

We strongly recommend that practitioners avoid prescribing meloxicam SC in cats. This recommendation is emphatic in situations where concurrent dehydration and/or hypotension are possible.

Genetic Risk Score Improves Risk Stratification for Anticoagulation-Related Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is the most devastating adverse outcome for patients on anticoagulants. Clinical risk scores that quantify bleeding risk can guide decision-making in situations when indication or duration for anticoagulation is uncertain. We investigated whether integration of a genetic risk score into an existing risk factor-based CRS could improve risk stratification for anticoagulation-related ICH.

METHODS

We constructed 153 genetic risk scores from genome-wide association data of 1545 ICH cases and 1481 controls and validated them in 431 ICH cases and 431 matched controls from the population-based UK Biobank. The score that explained the largest variance in ICH risk was selected and tested for prediction of incident ICH in an independent cohort of 5530 anticoagulant users. A CRS for major anticoagulation-related hemorrhage, based on 8/9 components of the HAS-BLED score, was compared with a combined clinical and genetic risk score incorporating an additional point for high genetic risk for ICH.

RESULTS

Among anticoagulated individuals, 94 ICH occurred over a mean follow-up of 11.9 years. Compared with the lowest genetic risk score tertile, being in the highest tertile was associated with a two-fold increased risk for incident ICH (hazard ratio, 2.08 [95% CI, 1.22-3.56]). Although the CRS predicted incident ICH with a hazard ratio of 1.24 per 1-point increase (95% CI [1.01-1.53]), adding a point for high genetic ICH risk led to a stronger association (hazard ratio of 1.33 per 1-point increase [95% CI, 1.11-1.59]) with improved risk stratification (C index 0.57 versus 0.53) and maintained calibration (integrated calibration index 0.001 for both). The new clinical and genetic risk score showed 19% improvement in high-risk classification among individuals with ICH and a net reclassification improvement of 0.10.

CONCLUSIONS

Among anticoagulant users, a prediction score incorporating genomic information is superior to a clinical risk score alone for ICH risk stratification and could serve in clinical decision-making.

The interplay between inflammatory cytokines and cardiometabolic disease: bi-directional mendelian randomisation study

Objective

To leverage large scale genetic association data to investigate the interplay between circulating cytokines and cardiometabolic traits, and thus identifying potential therapeutic targets.

Design

Bi-directional Mendelian randomisation study.

Setting

Genome-wide association studies from three Finnish cohorts (Northern Finland Birth Cohort 1966, Young Finns Study, or FINRISK study), and genetic association summary statistics pooled from observational studies for expression quantitative trait loci and cardiometabolic traits.

Participants

Data for 47 circulating cytokines in 13 365 individuals from genome-wide association studies, summary statistic data for up to 21 735 individuals on circulating cytokines, summary statistic gene expression data across 49 tissues in 838 individuals, and summary statistic data for up to 1 320 016 individuals on cardiometabolic traits.

Interventions

Relations between circulating cytokines and cardiovascular, anthropometric, lipid, or glycaemic traits (coronary artery disease, stroke, type 2 diabetes mellitus, body mass index, waist circumference, waist to hip ratio, systolic blood pressure, glycated haemoglobin, high density lipoprotein cholesterol, low density lipoprotein cholesterol, total cholesterol, triglycerides, C reactive protein, glucose, fasting insulin, and lifetime smoking).

Main outcome methods

Genetic instrumental variables that are biologically plausible for the circulating cytokines were generated. The effects of cardiometabolic risk factors on concentrations of circulating cytokines, circulating cytokines on other circulating cytokines, and circulating cytokines on cardiometabolic outcomes were investigated.

Results

Genetic evidence (mendelian randomisation P<0.0011) suggests that higher body mass index, waist circumference, smoking, higher concentrations of lipids, and systolic blood pressure increase circulating concentrations of several inflammatory cytokines and C reactive protein. Evidence for causal relations (mendelian randomisation P<0.0011) were noted between circulating cytokines, including a key role of vascular endothelial growth factor on influencing the concentrations of 10 other cytokines. Both mendelian randomisation (P<0.05) and colocalisation (posterior probability >0.5) suggested that coronary artery disease risk is increased by higher concentrations of circulating tumour necrosis factor related apoptosis-inducing ligand (TRAIL), interleukin-1 receptor antagonist (IL1RA), and macrophage colony-stimulating factor (MCSF).

Conclusion

This study offers insight into inflammatory mediators of cardiometabolic risk factors, cytokine signalling cascades, and effects of circulating cytokines on different cardiometabolic outcomes.

Abstract WMP106: Sex-stratified Transethnic GWAS Meta-analysis Identifies Novel Candidates For Early Onset Ischemic Stroke

Background: Early onset ischemic stroke (IS) affects males and females unequally, but the etiologic background of the sex differences remains inadequately understood. We hypothesize that stratifying GWAS by sex provides an opportunity to 1) identify loci that shed light on mechanisms and pathways relevant to sex specific effects in IS and 2) discover novel IS loci.

Methods: We performed a sex-stratified transethnic GWAS meta-analysis in 6,879 female IS cases and 11,264 male cases < 60 years-old and > 700,000 sex-matched controls from the Early Onset Stroke Genetics Consortium. We tested for difference (p-diff) between the men- and women-specific beta-estimates with corresponding standard errors using the t statistics.

Results: We found genome-wide significant evidence for association (p < 5 х 10 -8 ) at a locus near NYAP2 for females (chr2:225661726:C:CT, p = 2.11 х 10 -8 , OR = 1.38, p-diff = 1.69 х 10 -4 ) and in PIAS4 for males (chr19:4013652:C:CA, p = 6.29 х 10 -9 , OR = 0.85, p-diff = 0.02) in transethnic analysis. NYAP2 has previously shown suggestive evidence for association with early onset menopause. PIAS4 , a candidate gene for migraine, has shown sex-specific expression levels in migraine patients compared to controls. Additional loci with suggestive evidence (p < 1 х 10 -6 ) for association in a sex-dependent manner included MMP1-MMP3 - MMP12 , a previously known stroke locus, for males (chr11:102822455:A:G, p = 3.99 х 10 -7 , OR = 1.17, p-diff = 0.02), and a novel stroke locus near TMX1 , a transmembrane platelet protein, for females (chr14:51193174:G:C, p = 4.15 х 10 -7 , OR = 1.76, p-diff = 4.08 х 10 -3 ). The known early onset IS locus ABO did not show evidence for sex-specific association despite suggestive association in the male stratified analysis (chr9:133274295:A:T, p = 3.15 х 10 -7 , OR = 1.17, p-diff = 0.81).

Conclusions: We identified potential novel stroke loci and evidence for sex differences at other biologically relevant loci by stratifying GWAS by sex. To our knowledge, our cohort represents the largest early onset IS GWAS cohort to date. However, our findings require verification in large sample sizes and also evaluation in older onset IS. Sex-specific association analysis is a potentially useful tool for characterizing the genetic basis of early onset IS.

Brucella suis in three dogs: presentation, diagnosis and clinical management

Brucella suis is an emerging, zoonotic disease predominantly affecting dogs and humans that engage in feral pig hunting in Australia and other countries. Although B. suis infection in dogs shares some clinical similarities to the host-adapted species (B. canis), B. suis remains an incompletely understood pathogen in dogs with limited published data on its pathogenesis and clinical features. This case series describes the presentations, diagnosis, and clinical management of B. suis infection in three dogs: (1) a bitch with dystocia, abortion and mastitis; (2) an entire male dog with septic arthritis and presumptive osteomyelitis; and (3) a castrated male dog with lymphadenitis. Unique features of these cases are reported including the first documented detection of B. suis from milk and isolation from lymph nodes of canine patients, as well as the follow-up of pups born to a B. suis-infected bitch. Consistent with previous reports, all three dogs showed a favourable clinical response to combination antibiotic therapy with rifampicin and doxycycline. Individually tailored drug regimens were required based on the clinical presentation and other factors, including owner expectations and compliance with therapy as well as a zoonotic risk assessment (generally considered low, except around time of whelping). The authors include their recommendations for the clinical management of dogs that are at-risk or seropositive for B. suis with or without clinical signs or laboratory-confirmed infection.

Polygenic Effect on Tau Pathology Progression in Alzheimer's Disease

OBJECTIVE

Polygenic variation accounts for a substantial portion of the risk of Alzheimer's disease (AD), but its effect on the rate of fibrillar-tau accumulation as a key driver of dementia symptoms is unclear.

METHODS

We combined the to-date largest number of genetic risk variants of AD (n = 85 lead single-nucleotide polymorphisms [SNPs]) from recent genome-wide association studies (GWAS) to generate a polygenic score (PGS). We assessed longitudinal tau-positron emission tomography (PET), amyloid-PET, and cognition in 231 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Using the PGS, together with global amyloid-PET, we predicted the rate of tau-PET increases in Braak-stage regions-of-interest and cognitive decline. We also assessed PGS-risk enrichment effects on the required sample size in clinical trials targeting tau pathology.

RESULTS

We found that a higher PGS was associated with higher rates of tau-PET accumulation, in particular at elevated amyloid-PET levels. The tau-PET increases mediated the association between PGS and faster cognitive decline. Risk enrichment through high PGS afforded sample size savings by 34%.

INTERPRETATION

Our results demonstrate that the PGS predicts faster tau progression and thus cognitive decline, showing utility to enhance statistical power in clinical trials. ANN NEUROL 2023.

Genetic proxies for PCSK9 inhibition associate with lipoprotein(a): Effects on coronary artery disease and ischemic stroke

BACKGROUND AND AIMS

Post hoc analyses of clinical trials show that PCSK9 inhibitors might lower lipoprotein(a), but whether this effect contributes to reductions in cardiovascular risk remains unknown. We aimed to assess whether genetically proxied PCSK9 inhibition influences lipoprotein(a) (Lp(a)), and whether any such effect could mediate its effects on coronary artery disease (CAD) and ischemic stroke (IS).

METHODS

To explore associations between the genetic proxies for PCSK9 inhibitors and Lp(a) levels, we used UK Biobank data (310,020 individuals). We identified 10 variants in the PCSK9 gene associated with lower PCSK9 and LDL-C levels as proxies for PCSK9 inhibition. We explored the effects of genetically proxied PCSK9 inhibition on Lp(a) levels, as well as on odds of CAD (60,801 cases, 184,305 controls) and IS (60,341 cases, 454,450 controls) in two-sample Mendelian randomization analyses. In mediation analyses, we assessed the effects of genetically proxied PCSK9 inhibition on CAD and IS mediated through reductions in Lp(a) levels.

RESULTS

Genetically proxied PCSK9 inhibition (1-SD decrement in PCSK9 concentration; corresponding to 20.6 mg/dl decrement in LDL-C levels) was associated with a 4% decrease in log-Lp(a) levels (beta: -0.038, 95%CI: -0.053 to -0.023). We estimated a 0.8% reduction in the odds for CAD (OR: 0.992, 95%CI: 0.989-0.995) and a 0.5% reduction in the odds for atherosclerotic IS (OR: 0.995, 95%CI: 0.992-0.998) due to reductions in Lp(a) levels through genetically proxied PCSK9 inhibition, corresponding to 3.8% and 3.2% of the total effects, respectively.

CONCLUSIONS

Genetic proxies for PCSK9 inhibition are associated with lower Lp(a) levels. However, Lp(a) lowering explains only a small proportion of the total effects of genetic proxies for PCSK9 inhibitors on risk of CAD and IS.

Stroke genetics informs drug discovery and risk prediction across ancestries

Previous genome-wide association studies (GWASs) of stroke - the second leading cause of death worldwide - were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries.

Contribution of Common Genetic Variants to Risk of Early-Onset Ischemic Stroke

BACKGROUND AND OBJECTIVES

Current genome-wide association studies of ischemic stroke have focused primarily on late-onset disease. As a complement to these studies, we sought to identify the contribution of common genetic variants to risk of early-onset ischemic stroke.

METHODS

We performed a meta-analysis of genome-wide association studies of early-onset stroke (EOS), ages 18-59 years, using individual-level data or summary statistics in 16,730 cases and 599,237 nonstroke controls obtained across 48 different studies. We further compared effect sizes at associated loci between EOS and late-onset stroke (LOS) and compared polygenic risk scores (PRS) for venous thromboembolism (VTE) between EOS and LOS.

RESULTS

We observed genome-wide significant associations of EOS with 2 variants in ABO, a known stroke locus. These variants tag blood subgroups O1 and A1, and the effect sizes of both variants were significantly larger in EOS compared with LOS. The odds ratio (OR) for rs529565, tagging O1, was 0.88 (95% confidence interval [CI]: 0.85-0.91) in EOS vs 0.96 (95% CI: 0.92-1.00) in LOS, and the OR for rs635634, tagging A1, was 1.16 (1.11-1.21) for EOS vs 1.05 (0.99-1.11) in LOS; p-values for interaction = 0.001 and 0.005, respectively. Using PRSs, we observed that greater genetic risk for VTE, another prothrombotic condition, was more strongly associated with EOS compared with LOS (p = 0.008).

DISCUSSION

The ABO locus, genetically predicted blood group A, and higher genetic propensity for venous thrombosis are more strongly associated with EOS than with LOS, supporting a stronger role of prothrombotic factors in EOS.

Frequency and Phenotype Associations of Rare Variants in 5 Monogenic Cerebral Small Vessel Disease Genes in 200,000 UK Biobank Participants

BACKGROUND AND OBJECTIVES

Based on previous case reports and disease-based cohorts, a minority of patients with cerebral small vessel disease (cSVD) have a monogenic cause, with many also manifesting extracerebral phenotypes. We investigated the frequency, penetrance, and phenotype associations of putative pathogenic variants in cSVD genes in the UK Biobank (UKB), a large population-based study.

METHODS

We used a systematic review of previous literature and ClinVar to identify putative pathogenic rare variants in CTSA, TREX1, HTRA1, and COL4A1/2. We mapped phenotypes previously attributed to these variants (phenotypes-of-interest) to disease coding systems used in the UKB's linked health data from UK hospital admissions, death records, and primary care. Among 199,313 exome-sequenced UKB participants, we assessed the following: the proportion of participants carrying ≥1 variant(s); phenotype-of-interest penetrance; and the association between variant carrier status and phenotypes-of-interest using a binary (any phenotype present/absent) and phenotype burden (linear score of the number of phenotypes a participant possessed) approach.

RESULTS

Among UKB participants, 0.5% had ≥1 variant(s) in studied genes. Using hospital admission and death records, 4%-20% of variant carriers per gene had an associated phenotype. This increased to 7%-55% when including primary care records. Only COL4A1 variant carrier status was significantly associated with having ≥1 phenotype-of-interest and a higher phenotype score (OR = 1.29, p = 0.006).

DISCUSSION

While putative pathogenic rare variants in monogenic cSVD genes occur in 1:200 people in the UKB population, only approximately half of variant carriers have a relevant disease phenotype recorded in their linked health data. We could not replicate most previously reported gene-phenotype associations, suggesting lower penetrance rates, overestimated pathogenicity, and/or limited statistical power.

An association of VDR gene polymorphism in hypovitaminosis D mediated secondary hyperparathyroidism in adolescent girls; a tertiary hospital study in central India

Vitamin D is required to maintain normal serum calcium and phosphate levels that help normal bone mineralization, nerve conduction, muscle contraction, immune function, cell proliferation, and differentiation. Interventions including vitamin D supplementation may not improve vitamin D deficiency, as various complex genomic actions could contribute to vitamin D deficiency in the Indian population. Thus, we assessed hypovitaminosis D's relationship with vitamin D receptor (VDR) gene polymorphism and evaluated parathyroid hormone (PTH) levels in seemingly healthy adolescent school-going girls. We included 100 school-going girls (aged 12-17 years) studying in four schools of different socio-economic strata of Bhopal, India. The selected participants were divided into four groups based on the school in which they were studying. Blood samples were tested for serum calcium, phosphorus, PTH, ALP, vitamin D 25(OH) D, and albumin levels.VDR polymorphism was detected through the PCR-RFLP. Data were analyzed using the chi-square test, ANOVA, and linear regression. The difference in the age, calcium, ALP, and vitamin D values between the four groups were significant (P < 0.05), whereas high PTH levels (80%) were found. A higher prevalence of homozygous polymorphic allele demonstrates a molecular signature for severe secondary hyperparathyroidism. Hypovitaminosis D ranged from 84.9% to 100%, and a high prevalence of VDR polymorphism was observed. Attention must be paid to the health of this age group of school-going girls as hypovitaminosis D and associated VDR gene polymorphism could be the reason for secondary hyperparathyroidism (SHPT), showing changes in bone mineral density in these adolescent girls to ensure their future health.

Genetically predicted on-statin LDL response is associated with higher intracerebral haemorrhage risk

Statins lower low-density lipoprotein cholesterol and are widely used for the prevention of atherosclerotic cardiovascular disease. Whether statin-induced low-density lipoprotein reduction increases risk of intracerebral haemorrhage has been debated for almost two decades. Here, we explored whether genetically predicted on-statin low-density lipoprotein response is associated with intracerebral haemorrhage risk using Mendelian randomization. Using genomic data from randomized trials, we derived a polygenic score from 35 single nucleotide polymorphisms of on-statin low-density lipoprotein response and tested it in the population-based UK Biobank. We extracted statin drug and dose information from primary care data on a subset of 225 195 UK Biobank participants covering a period of 29 years. We validated the effects of the genetic score on longitudinal low-density lipoprotein measurements with generalized mixed models and explored associations with incident intracerebral haemorrhage using Cox regression analysis. Statins were prescribed at least once to 75 973 (31%) of the study participants (mean 57 years, 55% females). Among statin users, mean low-density lipoprotein decreased by 3.45 mg/dl per year [95% confidence interval (CI): (-3.47, -3.42)] over follow-up. A higher genetic score of statin response [1 standard deviation (SD) increment] was associated with significant additional reductions in low-density lipoprotein levels [-0.05 mg/dl per year, (-0.07, -0.02)], showed concordant lipidomic effects on other lipid traits as statin use and was associated with a lower risk for incident myocardial infarction [hazard ratio per SD increment 0.98 95% CI (0.96, 0.99)] and peripheral artery disease [hazard ratio per SD increment 0.93 95% CI (0.87, 0.99)]. Over a 11-year follow-up period, a higher genetically predicted statin response among statin users was associated with higher intracerebral haemorrhage risk in a model adjusting for statin dose [hazard ratio per SD increment 1.16, 95% CI (1.05, 1.28)]. On the contrary, there was no association with intracerebral haemorrhage risk among statin non-users (P = 0.89). These results provide further support for the hypothesis that statin-induced low-density lipoprotein reduction may be causally associated with intracerebral haemorrhage risk. While the net benefit of statins for preventing vascular disease is well-established, these results provide insights about the personalized response to statin intake and the role of pharmacological low-density lipoprotein lowering in the pathogenesis of intracerebral haemorrhage.

Associations of genetically predicted IL-6 signaling with cardiovascular disease risk across population subgroups

BACKGROUND

Interleukin 6 (IL-6) signaling is being investigated as a therapeutic target for atherosclerotic cardiovascular disease (CVD). While changes in circulating high-sensitivity C-reactive protein (hsCRP) are used as a marker of IL-6 signaling, it is not known whether there is effect heterogeneity in relation to baseline hsCRP levels or other cardiovascular risk factors. The aim of this study was to explore the association of genetically predicted IL-6 signaling with CVD risk across populations stratified by baseline hsCRP levels and cardiovascular risk factors.

METHODS

Among 397,060 White British UK Biobank participants without known CVD at baseline, we calculated a genetic risk score for IL-6 receptor (IL-6R)-mediated signaling, composed of 26 variants at the IL6R gene locus. We then applied linear and non-linear Mendelian randomization analyses exploring associations with a combined endpoint of incident coronary artery disease, ischemic stroke, peripheral artery disease, aortic aneurysm, and cardiovascular death stratifying by baseline hsCRP levels and cardiovascular risk factors.

RESULTS

The study participants (median age 59 years, 53.9% females) were followed-up for a median of 8.8 years, over which time a total of 46,033 incident cardiovascular events occurred. Genetically predicted IL-6R-mediated signaling activity was associated with higher CVD risk (hazard ratio per 1-mg/dL increment in absolute hsCRP levels: 1.11, 95% CI: 1.06-1.17). The increase in CVD risk was linearly related to baseline absolute hsCRP levels. There was no evidence of heterogeneity in the association of genetically predicted IL-6R-mediated signaling with CVD risk when stratifying the population by sex, age, body mass index, estimated glomerular filtration rate, or systolic blood pressure, but there was evidence of greater associations in individuals with low-density lipoprotein cholesterol ≥ 160 mg/dL.

CONCLUSIONS

Any benefit of inhibiting IL-6 signaling for CVD risk reduction is likely to be proportional to absolute reductions in hsCRP levels. Therapeutic inhibition of IL-6 signaling for CVD risk reduction should therefore prioritize those individuals with the highest baseline levels of hsCRP.

AB0602 Temporal artery biopsy positivity rates vary more between similar hospitals than by length, with particular variation between geographic regions

Background

Clinical practice surrounding giant cell arteritis (GCA) diagnosis, including the use of temporal artery biopsy (TAB) where appropriate, needs to be consistently accurate to minimise both GCA-related end-organ damage and unnecessary glucocorticosteroid toxicity in all patients. Despite this imperative, the delivery of such clinical care, which can be measured by diagnostic investigation performance characteristics such as TAB positivity rates, varies substantially between different hospitals as it is traditionally reliant on unstructured clinical intuition. While clinical care practices plausibly might be more consistent between neighbouring hospitals given they frequently exchange medical staff and use common teaching sources, these factors are less likely to be applicable when comparing hospitals in different geographical regions within a country, even though educational standards, online information resources, and access to clinical care should be consistent. It therefore stands to reason that variation of diagnostic practice might be greater between geographically distant hospitals.

Objectives

To compare clinical practice surrounding GCA diagnosis, using TAB positivity rates, between similar hospitals in the same city and a geographically distant city in a different region, to understand the contribution of geographic separation to variance in practice.

Methods

TAB histopathological reports were reviewed at three tertiary referral hospital centres: two with neighbouring catchments in the same city, and one in a different city in a neighbouring geographical region in the same country. All three had similar resourcing and catchment demographics during the study period, and none used formal clinical risk stratification scores for GCA pre-test probability. Characteristics including age, sex, biopsy laterality, biopsy length, and hospital were captured, in addition to key histopathological features. Multivariable logistic regression with site-varying intercept was performed, using cubic splines for biopsy length to account for the non-linearity observed.

Results

TAB reports from 708 patients were captured between the three hospitals in two geographical regions. All three sites had a median age of 74 years, had 67-69% of patients being female, and reported median biopsy length between 1.7-2.0cm (Table 1). Despite these similarities, they reported positivity rates varying widely (16% and 24% in Region 1, 29% in Region 2). Apart from age, hospital site was the strongest contributing factor to TAB positivity, with length having little effect outside the very extreme high end and 90% of patients had a biopsy length <4.8cm (Figure 1). For these patients, hospital site differentiated TAB positivity across all biopsy lengths, with Region 2 reporting the highest TAB positivity odds ratio of 2.39 (95%CI: 1.37-4.19).

Table 1.CharacteristicSite1Region1 N = 218Site2Region1 N = 361Site1Region2 N = 129Bilateral laterality (%)66 (30%)105 (29%)1 (0.8%)Biopsy length (cm, median (IQR))2.0 (1.4, 3.0)1.7 (1.2, 3.5)1.7 (1.4, 2.2)Female sex (%)149 (68%)249 (69%)86 (67%)Age (y, median (IQR))74 (65, 81)74 (65, 80)74 (68, 81)TAB positivity (%)34 (16%)88 (24%)38 (29%)Figure 1.

Marginal probabilities of positive TAB obtained from the multivariable logistic regression model (A) across biopsy lengths, with 80% of observed lengths falling between the two vertical red lines (10% and 90% deciles); (B) across hospital sites; (C) across patient age.

Conclusion

Hospital site contributes more greatly to variation in GCA diagnosis clinical practice than demographics or other clinical features do, with particular variation between geographic regions. As part of clinical care standards, using a replicable pre-test GCA probability score1 to select patients is likely to be as important to diagnosis as the diagnostic tool characteristics themselves.

References

[1]Laskou F, et al. A probability score to aid the diagnosis of suspected giant cell arteritis. Clin Exp Rheumatol. 2019 Jan 1;37(Suppl 117):104-8.

Disclosure of Interests

None declared

Detection of Brucella spp. during a serosurvey of pig-hunting and regional pet dogs in eastern Australia

Brucellosis is a zoonotic disease with worldwide distribution. Brucella suis serotype 1 is thought to be maintained in the Australian feral pig population, with disease prevalence higher in Queensland (Qld) than New South Wales (NSW). Pig hunting is a popular recreational activity in rural Qld and NSW, with feral pigs in these states thought to carry B. suis. Brucellosis associated with B. suis has been diagnosed in dogs engaged in pig hunting in some of these areas. A total of 431 dogs from northern Qld and north‐west NSW were recruited. Two distinct cohorts of clinically healthy dogs were tested – (1) 96 dogs from central, north and far north Queensland actively engaged in pig‐hunting and (2) 335 dogs from rural and remote north‐west NSW that were primarily companion (non‐pig hunting) animals. Serum samples were tested for antibodies to Brucella spp. using the Rose Bengal test (RBT) test followed by complement fixation testing (CFT) for RBT‐positive samples. A subset of samples was retested using RBT and CFT. Seven dogs were considered seropositive for B. suis from Qld and remote NSW, including 4/96 (4.2%; 95% CI 3.5% to 4.3%) from the pig‐hunting cohort and 3/335 (0.9%) from the regional pet dog cohort. The use of RBT and CFT in dogs to detect anti‐Brucella antibodies requires validation. Veterinarians treating pig‐hunting dogs and physicians treating pig hunters in central, north and far north Qld need to be aware of the zoonotic risk posed by B. suis to these groups.

Feline immunodeficiency virus (FIV) infection in domestic pet cats in Australia and New Zealand: Guidelines for diagnosis, prevention and management

Despite the passage of over 30 years since its discovery, the importance of feline immunodeficiency virus (FIV) on the health and longevity of infected domestic cats is hotly debated amongst feline experts. Notwithstanding the absence of good quality information, Australian and New Zealand (NZ) veterinarians should aim to minimise the exposure of cats to FIV. The most reliable way to achieve this goal is to recommend that all pet cats are kept exclusively indoors, or with secure outdoor access (e.g., cat enclosures, secure gardens), with FIV testing of any in‐contact cats. All animal holding facilities should aim to individually house adult cats to limit the spread of FIV infection in groups of animals that are stressed and do not have established social hierarchies. Point‐of‐care (PoC) FIV antibody tests are available in Australia and NZ that can distinguish FIV‐infected and uninfected FIV‐vaccinated cats (Witness™ and Anigen Rapid™). Although testing of whole blood, serum or plasma remains the gold standard for FIV diagnosis, PoC testing using saliva may offer a welfare‐friendly alternative in the future. PCR testing to detect FIV infection is not recommended as a screening procedure since a negative PCR result does not rule out FIV infection and is only recommended in specific scenarios. Australia and NZ are two of three countries where a dual subtype FIV vaccine (Fel‐O‐Vax® FIV) is available and offers a further avenue for disease prevention. Since FIV vaccination only has a reported field effectiveness of 56% in Australia, and possibly lower in NZ, FIV‐vaccinated cats should undergo annual FIV testing prior to annual FIV re‐vaccination using a suitable PoC kit to check infection has not occurred in the preceding year. With FIV‐infected cats, clinicians should strive to be even more thorough than usual at detecting early signs of disease. The most effective way to enhance the quality of life and life expectancy of FIV‐infected cats is to optimise basic husbandry and to treat any concurrent conditions early in the disease course. Currently, no available drugs are registered for the treatment of FIV infection. Critically, the euthanasia of healthy FIV‐infected cats, and sick FIV‐infected cats without appropriate clinical investigations, should not occur.

Shared genetic background between SARS-CoV-2 infection and large artery stroke

BACKGROUND AND AIMS

Increased risk of stroke, particularly large artery stroke (LAS), has been observed in patients with COVID-19. The biological processes underlying the observed higher risk are still unknown. We explored the association between stroke subtypes and COVID-19 susceptibility to understand whether biological mechanisms specific to SARS-CoV-2 uptake/infection could be leading to excess stroke risk in this population.

PATIENTS AND METHODS

We constructed a polygenic risk score (PRS) of COVID-19 susceptibility and tested its association with stroke subtypes using individual- and summary-level genetic data (SiGN, MEGASTROKE). We generated co-expression networks of genes involved in SARS-CoV-2 uptake/infection (ACE2, TMPRSS2, BEST3, ISLR2 and ADAM17) based on existing tissue expression libraries. Gene-based association testing was performed using S-PrediXcan and VEGAS2. Permutation independence tests were performed to assess SARS-CoV-2-related gene enrichment in stroke and its subtypes.

RESULTS

Our PRS demonstrated an association between COVID-19 susceptibility and LAS in SiGN (OR = 1.05 per SD increase, 95% CI: (1.00, 1.10), p = 0.04) and MEGASTROKE (β = 0.510, 95% CI: (0.242, 0.779), FDR-p = 0.0019). The SARS-CoV-2 risk-related ISLR2 co-expression gene network was significantly associated with genetic risk of LAS in aorta, tibial arteries, and multiple brain regions (P < 0.05).

CONCLUSION

Presence of genetic correlation and significant pathway enrichment suggest that increases in LAS risk reported in COVID-19 patients may be intrinsic to the viral infection, rather than a more generalized response to severe illness.

Complicated Carotid Artery Plaques and Risk of Recurrent Ischemic Stroke or TIA

BACKGROUND

Complicated nonstenosing carotid artery plaques (CAPs) are an under-recognized cause of stroke.

OBJECTIVES

The purpose of this study was to determine whether complicated CAP ipsilateral to acute ischemic anterior circulation stroke (icCAP) are associated with recurrent ischemic stroke or transient ischemic attack (TIA).

METHODS

The CAPIAS (Carotid Plaque Imaging in Acute Stroke) multicenter study prospectively recruited patients with ischemic stroke restricted to the territory of a single carotid artery. Complicated (AHA-lesion type VI) CAP were defined by multisequence, contrast-enhanced carotid magnetic resonance imaging obtained within 10 days from stroke onset. Recurrent events were assessed after 3, 12, 24, and 36 months. The primary outcome was recurrent ischemic stroke or TIA.

RESULTS

Among 196 patients enrolled, 104 patients had cryptogenic stroke and nonstenosing CAP. During a mean follow-up of 30 months, recurrent ischemic stroke or TIA occurred in 21 patients. Recurrent events were significantly more frequent in patients with icCAP than in patients without icCAP, both in the overall cohort (incidence rate [3-year interval]: 9.50 vs 3.61 per 100 patient-years; P = 0.025, log-rank test) and in patients with cryptogenic stroke (10.92 vs 1.82 per 100 patient-years; P = 0.003). The results were driven by ipsilateral events. A ruptured fibrous cap (HR: 4.91; 95% CI: 1.31-18.45; P = 0.018) and intraplaque hemorrhage (HR: 4.37; 95% CI: 1.20-15.97; P = 0.026) were associated with a significantly increased risk of recurrent events in patients with cryptogenic stroke.

CONCLUSIONS

Complicated CAP ipsilateral to acute ischemic anterior circulation stroke are associated with an increased risk of recurrent ischemic stroke or TIA. Carotid plaque imaging identifies high-risk patients who might be suited for inclusion into future secondary prevention trials. (Carotid Plaque Imaging in Acute Stroke [CAPIAS]; NCT01284933).

Cardiac Risk Factors for Stroke: A Comprehensive Mendelian Randomization Study

BACKGROUND

Observational studies suggest an association of stroke with cardiac traits beyond atrial fibrillation, the leading source of cardioembolism. However, controversy remains regarding a causal role of these traits in stroke pathogenesis. Here, we leveraged genetic data to systematically assess associations between cardiac traits and stroke risk using a Mendelian Randomization framework.

METHODS

We studied 66 cardiac traits including cardiovascular diseases, magnetic resonance imaging-derived cardiac imaging, echocardiographic imaging, and electrocardiographic measures, as well as blood biomarkers in a 2-sample Mendelian Randomization approach. Genetic predisposition to each trait was explored for associations with risk of stroke and stroke subtypes in data from the MEGASTROKE consortium (40 585 cases/406 111 controls). Using multivariable Mendelian Randomization, we adjusted for potential pleiotropic or mediating effects relating to atrial fibrillation, coronary artery disease, and systolic blood pressure.

RESULTS

As expected, we observed strong independent associations between genetic predisposition to atrial fibrillation and cardioembolic stroke and between genetic predisposition to coronary artery disease as a proxy for atherosclerosis and large-artery stroke. Our data-driven analyses further indicated associations of genetic predisposition to both heart failure and lower resting heart rate with stroke. However, these associations were explained by atrial fibrillation, coronary artery disease, and systolic blood pressure in multivariable analyses. Genetically predicted P-wave terminal force in V1, an electrocardiographic marker for atrial cardiopathy, was inversely associated with large-artery stroke.

CONCLUSIONS

Available genetic data do not support substantial effects of cardiac traits on the risk of stroke beyond known clinical risk factors. Our findings highlight the need to carefully control for confounding and other potential biases in studies examining candidate cardiac risk factors for stroke.

Seroprevalence of Coxiella burnetii in pig-hunting dogs from north Queensland, Australia

The causative agent of Q fever, Coxiella burnetii, is endemic to Queensland and is one of the most important notifiable zoonotic diseases in Australia. The reservoir species for C. burnetii are classically ruminants, including sheep, cattle and goats. There is increasing evidence of C. burnetii exposure in dogs across eastern and central Australia. The present study aimed to determine if pig-hunting dogs above the Tropic of Capricorn in Queensland had similar rates of C. burnetii exposure to previous serosurveys of companion dogs in rural north-west New South Wales. A total of 104 pig-hunting dogs had serum IgG antibody titres to phase I and phase 2 C. burnetii determined using an indirect immunofluorescence assay test. Almost one in five dogs (18.3%; 19/104; 95% confidence interval 9.6%-35.5%) were seropositive to C. burnetii, with neutered dogs more likely to test positive compared to entire dogs (P = 0.0497). Seropositivity of the sampled pig-hunting dogs was one of the highest recorded in Australia. Thirty-nine owners of the pig-hunting dogs completed a survey, revealing 12.8% (5/39) had been vaccinated against Q fever and 90% (35/39) were aware that both feral pigs and dogs could potentially be sources of C. burnetii. Our findings indicate that pig hunters should be aware of the risk of exposure to Q fever during hunts and the sentinel role their dogs may play in C. burnetii exposure.

Physician-Confirmed and Administrative Definitions of Stroke in UK Biobank Reflect the Same Underlying Genetic Trait

Background

Stroke in UK Biobank (UKB) is ascertained via linkages to coded administrative datasets and self-report. We studied the accuracy of these codes using genetic validation.

Methods

We compiled stroke-specific and broad cerebrovascular disease (CVD) code lists (Read V2/V3, ICD-9/-10) for medical settings (hospital, death record, primary care) and self-report. Among 408,210 UKB participants, we identified all with a relevant code, creating 12 stroke definitions based on the code type and source. We performed genome-wide association studies (GWASs) for each definition, comparing summary results against the largest published stroke GWAS (MEGASTROKE), assessing genetic correlations, and replicating 32 stroke-associated loci.

Results

The stroke case numbers identified varied widely from 3,976 (primary care stroke-specific codes) to 19,449 (all codes, all sources). All 12 UKB stroke definitions were significantly correlated with the MEGASTROKE summary GWAS results (rg.81-1) and each other (rg.4-1). However, Bonferroni-corrected confidence intervals were wide, suggesting limited precision of some results. Six previously reported stroke-associated loci were replicated using ≥1 UKB stroke definition.

Conclusions

Stroke case numbers in UKB depend on the code source and type used, with a 5-fold difference in the maximum case-sample size. All stroke definitions are significantly genetically correlated with the largest stroke GWAS to date.

Abstract WMP99: Proteomics Study Of Stroke In Young Adults

Introduction: A prior systematic Mendelian randomization screen of 653 circulating proteins in a predominantly older ischemic stroke (IS) population identified a causal role for several established and novel biomarkers for IS and IS subtypes. We contrasted the magnitude of genetically determined levels of 6 of these biomarkers between early- and late-onset IS.

Methods: We constructed genetic risk scores (GRS) for these 6 protein biomarkers from previously published GWAS analyses carried out in European populations. Using regression analysis, we evaluated associations of these GRS with IS and IS subtypes in 10,549 early onset (ages 18-59) and 9,272 late onset (ages 60 and older) IS cases and associated controls. The Wald test was used to test for heterogeneity in the odds ratios between the two groups.

Results: Of the 6 biomarkers, only genetically determined protein levels of histo-blood group ABO system transferase were more strongly associated with early compared to late onset stroke (p < 0.002). Higher genetically determined levels of F11 and LPA and lower genetically determined levels of MMP12 were associated with both early and late onset IS with no evidence for differential effect sizes, while genetically determined levels of CD40 and SCARA5 showed no association with either early or late onset stroke. In subtype-specific analyses, increasing levels of genetically determined F11 were correlated with increased risk of all strokes in both groups. Higher genetically determined LPA levels were associated with large artery atherosclerotic (LAA) strokes in both groups, while lower genetically determined MMP12 levels were associated with LAA strokes in both groups.

Conclusions: Genetically determined histo-blood group ABO system transferase levels are more strongly associated with all strokes in early than in late onset stroke. Genetically determined blood protein levels of F11, LPA, and MMP12 were associated with both early and late onset stroke. Lack of association for CD40 and SCARA5 may be due to a smaller sample size than the initial discovery study.

Genome-wide analysis of 102,084 migraine cases identifies 123 risk loci and subtype-specific risk alleles

Migraine affects over a billion individuals worldwide but its genetic underpinning remains largely unknown. Here, we performed a genome-wide association study of 102,084 migraine cases and 771,257 controls and identified 123 loci, of which 86 are previously unknown. These loci provide an opportunity to evaluate shared and distinct genetic components in the two main migraine subtypes: migraine with aura and migraine without aura. Stratification of the risk loci using 29,679 cases with subtype information indicated three risk variants that seem specific for migraine with aura (in HMOX2, CACNA1A and MPPED2), two that seem specific for migraine without aura (near SPINK2 and near FECH) and nine that increase susceptibility for migraine regardless of subtype. The new risk loci include genes encoding recent migraine-specific drug targets, namely calcitonin gene-related peptide (CALCA/CALCB) and serotonin 1F receptor (HTR1F). Overall, genomic annotations among migraine-associated variants were enriched in both vascular and central nervous system tissue/cell types, supporting unequivocally that neurovascular mechanisms underlie migraine pathophysiology.

Abstract 154: Sex-specific Genome Wide Association Study Of Early-onset Ischemic Stroke

Introduction: Genetic studies of early-onset disease have been an effective strategy to identify novel pathways and drug targets generalizable also to later-onset disease. Few studies have investigated the sex-specific genetic associations with early-onset ischemic stroke even though several features of ischemic stroke differ between males and females. We hypothesized that stratifying the GWAS by sex would reveal novel stroke loci.

Methods: We performed a transethnic ischemic stroke GWAS of 3,056 female cases and 4,462 male cases < 60 years-old and 16,192 and 16,048 sex-matched controls, respectively, from the Early Onset Stroke Genetics Consortium.

Results: We identified a significant association in women with a locus in close proximity to TMX1 , a transmembrane platelet protein that inhibits platelet function. Additionally, we identified 2 other suggestive (P < 5 x 10 -6 ) loci in females (see Table), i.e., at APOH , which encodes beta2-glycoprotein I, an established GWAS locus for lipoprotein(a), and LRFN2 which has been previously reported to associate with obesity-related measures and type II diabetes. We observed suggestive evidence for association in males with MMP3/MMP12 , a known stroke susceptibility locus.

Conclusions: Despite a very modest sample size, sex-specific analyses identified suggestive associations at biologically important novel loci in females and a known stroke locus in males. Further studies of sex-specific associations in both early- and later-onset ischemic stroke are needed.

Migraine, Stroke, and Cervical Arterial Dissection: Shared Genetics for a Triad of Brain Disorders With Vascular Involvement

BACKGROUND AND OBJECTIVES

Migraine, stroke, and cervical artery dissection (CeAD) represent a triad of cerebrovascular disorders with pairwise comorbid relationships and vascular involvement. Larger samples and recent advances in methodology invite systematic exploration of their shared genetics.

METHODS

Genetic analyses leveraged summary statistics from genome-wide association studies of the largest available samples of each disorder, including subtypes of stroke (ischemic stroke, large artery stroke, small vessel stroke, and cardioembolic stroke) and migraine (with aura and without aura). For each pair of disorders, genetic correlation was assessed both on a genome-wide basis and within independent segments across the genome including known specific loci for each disorder. A cross-trait meta-analysis was used to identify novel candidate loci. Finally, potential causality of migraine susceptibility on stroke and CeAD was assessed by Mendelian randomization.

RESULTS

Among all pairs of disorders, genome-wide genetic correlation was observed only between CeAD and migraine, particularly MO. Local genetic correlations were more extensive between migraine and CeAD than those between migraine and stroke or CeAD and stroke and revealed evidence for novel CeAD associations at rs6693567 (ADAMTSL4/ECM1), rs11187838 (PLCE1), and rs7940646 (MRVI1) while strengthening prior subthreshold evidence at rs9486725 (FHL5) and rs650724 (LRP1). At known migraine loci, novel associations with stroke had concordant risk alleles for small vessel stroke at rs191602009 (CARF) and for cardioembolic stroke at rs55884259 (NKX2-5). Known migraine loci also revealed novel associations but with opposite risk alleles for all stroke, ischemic stroke, and small vessel stroke at rs55928386 (HTRA1), for large artery stroke at rs11172113 (LRP1), and for all stroke and ischemic stroke at rs1535791 and rs4942561 (both LRCH1), respectively. rs182923402 (near PTCH1) was a novel concordant locus for migraine and cardioembolic stroke. Mendelian randomization supported potential causal influences of migraine on CeAD (odds ratio [95% confidence interval] per doubling migraine prevalence = 1.69 [1.24-2.3], p = 0.0009) with concordant risk, but with opposite risk on large artery stroke (0.86 [0.76-0.96], p = 0.0067).

DISCUSSION

The findings emphasize shared genetic risk between migraine and CeAD while identifying loci with likely vascular function in migraine and shared but opposite genetic risk between migraine and stroke subtypes, and a central role of LRP1 in all 3 cerebrovascular disorders.

Abstract TMP99: Genetics Of Stroke Of Undetermined Source: Overlap With Known Stroke Etiologies And Associations With Modifiable Risk Factors

Introduction: Stroke etiology remains unknown in 30% of cases, hindering secondary prevention efforts. We leveraged human genetic data in order to identify evidence of overlap between stroke of undetermined source and defined stroke etiologies as well as causal relationships with modifiable risk factors.

Methods: We analyzed genome-wide data from 16,851 ischemic stroke cases and 32,473 controls from the NINDS Stroke Genetics Network with TOAST- and CCS-defined subtypes. Using genetic risk scores for large artery, cardioembolic, and small vessel stroke (LAS, CES, SVS) we assessed the degree of overlap with stroke of undetermined source and used pairwise GWAS to search for shared loci. We then applied Mendelian randomization (MR) to identify causal risk factors for stroke of undetermined source.

Results: There was significant overlap between stroke of undetermined source and all defined stroke subtypes at a genome-wide and locus level (19 shared loci with LAS, 2 with CES, 5 with SVS). Shared loci pointed to altered gene expression in arterial tissue and blood and atherosclerosis-related mechanisms. Further, genetically predicted carotid intima media thickness was associated with stroke of undetermined source. While genetic liability to atrial fibrillation also showed a significant association, this was attenuated in analyses excluding cases with incomplete diagnostic workup. MR analyses showed significant associations in blood pressure, diabetes, waist-to-hip ratio, inflammatory pathways (IL-6 signaling, MCP-1 levels), and elevated factor XI levels with stroke of undetermined source (Figure).

Conclusion: These analyses suggest that stroke of undetermined source shares genetic and modifiable risk factors with defined stroke subtypes. Together, they raise the hypothesis that refinement of current subtyping approaches can reduce the proportion of cases classified as undetermined and optimize secondary prevention strategies.

Cardiovascular Risk Factors and MRI Markers of Cerebral Small Vessel Disease: A Mendelian Randomization Study

BACKGROUND AND OBJECTIVES

Cardiovascular risk factors have been implicated in the etiology of cerebral small vessel disease (CSVD); however, whether the associations are causal remains unclear in part due to the susceptibility of observational studies to reverse causation and confounding. Here, we use mendelian randomization (MR) to determine which cardiovascular risk factors are likely to be involved in the etiology of CSVD.

METHODS

We used data from large-scale genome-wide association studies of European ancestry to identify genetic proxies for blood pressure, blood lipids, body mass index (BMI), type 2 diabetes, smoking initiation, cigarettes per day, and alcohol consumption. MR was performed to assess their association with 3 neuroimaging features that are altered in CSVD (white matter hyperintensities [WMH], fractional anisotropy [FA], and mean diffusivity [MD]) using genetic summary data from the UK Biobank (N = 31,855). Our primary analysis used inverse-weighted median MR, with validation using weighted median, MR-Egger, and a pleiotropy-minimizing approach. Finally, multivariable MR was performed to study the effects of multiple risk factors jointly.

RESULTS

MR analysis showed consistent associations across all methods for higher genetically proxied systolic and diastolic blood pressures with WMH, FA, and MD and for higher genetically proxied BMI with WMH. There was weaker evidence for associations between total cholesterol, low-density lipoprotein, smoking initiation, pulse pressure, and type 2 diabetes liability and at least 1 CSVD imaging feature, but these associations were not reproducible across all validation methods used. Multivariable MR analysis for blood pressure traits found that the effect was primarily through genetically proxied diastolic blood pressure across all CSVD traits.

DISCUSSION

Genetic predisposition to higher blood pressure, primarily diastolic blood pressure, and to higher BMI is associated with a higher burden of CSVD, suggesting a causal role. Improved management and treatment of these risk factors could reduce the burden of CSVD.

Additive Effects of Genetic Interleukin-6 Signaling Downregulation and Low-Density Lipoprotein Cholesterol Lowering on Cardiovascular Disease: A 2×2 Factorial Mendelian Randomization Analysis

Background Although trials suggest that anti-inflammatory approaches targeting interleukin (IL)-6 signaling can reduce cardiovascular risk, it remains unknown whether targeting IL-6 signaling could reduce risk additively to low-density lipoprotein cholesterol (LDL-C) lowering. Here, we assess interactions in associations of genetic downregulation of IL-6 signaling and LDL-C lowering with lifetime cardiovascular disease risk. Methods and Results Genetic scores for IL-6 signaling downregulation and LDL-C lowering were used to divide 408 225 White British individuals in UK Biobank into groups of lifelong exposure to downregulated IL-6 signaling, lower LDL-C, or both. Associations with risk of cardiovascular disease (coronary artery disease, ischemic stroke, peripheral artery disease, aortic aneurysm, vascular death) were explored in factorial Mendelian randomization. Compared with individuals with genetic IL-6 and LDL-C scores above the median, individuals with LDL-C scores lower than the median but IL-6 scores above the median had an odds ratio (OR) of 0.96 (95% CI, 0.93-0.98) for cardiovascular disease. A similar OR (0.96; 95% CI, 0.93-0.98) was estimated for individuals with genetic IL-6 scores below the median but LDL-C scores above the median. Individuals with both genetic scores lower than the median were at lower odds of cardiovascular disease (OR, 0.92; 95% CI, 0.90-0.95). There was no interaction between the 2 scores (relative excess risk attributed to interaction index, 0; synergy index, 1; P for multiplicative interaction=0.51). Genetic IL-6 score below the median was associated with lower cardiovascular disease risk across measured LDL-C strata (<100 or ≥100 mg/dL). Conclusions Genetically downregulated IL-6 signaling and genetically lowered LDL-C are associated with additively lower lifetime risk of cardiovascular disease. Future trials should explore combined IL-6 inhibition and LDL-C lowering treatments for cardiovascular prevention.