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Origin, evolution, and success of pbla, the gonococcal beta-lactamase plasmid, and implications for public health.
Neisseria gonorrhoeae is a leading cause of sexually transmitted infection (STI) and a priority AMR pathogen. Two narrow host range plasmids, pbla and pConj, have contributed to ending penicillin and tetracycline therapy, respectively, and undermine current prevention strategies including doxycycline post-exposure prophylaxis (Doxy-PEP). Here, we investigated the origin and evolution of the beta-lactamase plasmid, pbla. We demonstrate that pbla was likely acquired by the gonococcus from Haemophilus ducreyi, and describe the subsequent evolutionary pathways taken by the three major pbla variants. We show that the ability of pConj to spread pbla promotes their co-occurrence in the gonococcal population and the spread of pbla. Changes that mitigate fitness costs of pbla and the emergence of TEM beta-lactamases that confer increased resistance have contributed to the success of pbla. In particular, TEM-135, which has arisen in certain pbla variants, increases resistance to beta-lactams and only requires one amino acid change to become an extended spectrum beta-lactamase (ESBL). The evolution of pbla underscores the threat of plasmid-mediated resistance to current therapeutic and preventive strategies against gonococcal infection. Given the close relationship between pbla and pConj, widespread use of Doxy-PEP is likely to promote spread of both plasmids, strains which carry pConj and are resistant against third generation cephalosporins, and the emergence of plasmid-mediated ESBL in the gonococcus, with significant public health consequences.
Clinical and cost-effectiveness of lithium versus quetiapine augmentation for treatment-resistant depression in adults: LQD a pragmatic randomised controlled trial.
BACKGROUND: Lithium and several atypical antipsychotics are the recommended first-line augmentation options for treatment-resistant depression; however, few studies have compared them directly, and none for longer than 8 weeks. Consequently, there is little evidence-based guidance for clinicians when choosing an augmentation option for patients with treatment-resistant depression. OBJECTIVES: This trial examined whether it is more clinically and cost-effective to prescribe lithium or quetiapine augmentation therapy for patients with treatment-resistant depression over 12 months. DESIGN: This was a parallel group, multicentre, pragmatic, open-label superiority trial comparing the clinical and cost-effectiveness of lithium versus quetiapine augmentation of antidepressant medication in treatment-resistant depression. Participants were randomised 1 : 1 at baseline to the decision to prescribe either lithium or quetiapine. SETTING: Six National Health Service trusts in England. PARTICIPANTS: Eligible participants were aged ≥ 18 years, met Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria for major depressive disorder, scored ≥ 14 on the 17-item Hamilton Depression Rating Scale and whose depression had had an inadequate response to at least two therapeutic antidepressant treatment trials in the current episode, with a current antidepressant treatment at or above the therapeutic dose for ≥ 6 weeks. Patients with a history of psychosis or bipolar disorder were excluded. Patients were judged suitable for either treatment. INTERVENTIONS: After randomisation, pre-prescribing safety checks were undertaken as per standard care and trial clinicians decided whether to proceed with prescribing the allocated medication. Trial clinicians received recommendations for titration and dosing in line with current clinical guidelines; however, dosing regimens could be altered according to tolerability and response. Participants were followed up using weekly self-report questionnaires and 8-, 26- and 52-week research visits. MAIN OUTCOME MEASURES: The co-primary outcome measures were depressive symptom severity over 52 weeks, measured weekly using the self-rated Quick Inventory of Depressive Symptomatology, and time to all-cause treatment discontinuation of the trial medication. Economic analyses compared costs between the two treatment arms over 52 weeks, from a National Health Service and Personal Social Services perspective, and a societal perspective. RESULTS: Two hundred and twelve participants were randomised, 107 to quetiapine and 105 to lithium. The quetiapine arm showed a significantly greater reduction in depressive symptoms than the lithium arm over 52 weeks (quetiapine vs. lithium area under the differences curve = -68.36, 95% confidence interval: -129.95 to -6.76, p = 0.0296). Median days to discontinuation did not significantly differ between the two arms (quetiapine = 365.0, interquartile range = 57.0-365.0, lithium = 212.0, interquartile range = 21.0-365.0), p = 0.1196. Quetiapine was more cost effective than lithium. Thirty-two serious adverse events were recorded, only one of which was deemed possibly related to the intervention (lithium). LIMITATIONS: The trial was unblinded, therefore expectancies regarding the trial medications may have influenced the results. Further, there was substantial missing data for some of the secondary outcome measures. CONCLUSIONS: As well as being more cost-effective, quetiapine may be a more clinically effective augmentation option for treatment-resistant depression. FUTURE WORK: Examining predictors of treatment response, including clinical, sociodemographic and biological factors, will help establish whether there are additional factors to consider when choosing an augmentation treatment for treatment-resistant depression. TRIAL REGISTRATION: This trial is registered as ISRCTN16387615. FUNDING: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 14/222/02) and is published in full in Health Technology Assessment; Vol. 29, No. 12. See the NIHR Funding and Awards website for further award information.
Correction: Evaluating the generalisability of region-naïve machine learning algorithms for the identification of epilepsy in low-resource settings.
[This corrects the article DOI: 10.1371/journal.pdig.0000491.].
Dreaming of Better Treatments: Advances in Drug Development for Sleep Medicine and Chronotherapy.
Throughout history, the development of new sleep medicines has been driven by progress in our understanding of the mechanisms underlying sleep. Ancient civilisations used their understanding of the sedative nature of natural herbs and compounds to induce sleep. The discovery of barbiturates and bromides heralded a new era of synthetic sleep medicine in the 19th century. This was followed by the development of benzodiazepines that were used to inhibit signalling throughout the brain by promoting gamma-amino butyric acid release and thereby produce loss of consciousness. As our understanding of sleep has deepened, newer therapies have more specifically targeted the wake-inducing neurotransmitter orexin with fewer side effects. Given the newly highlighted role of kinases in sleep/wake regulation, we predict that the next breakthroughs in sleep medicine will likely target these kinases. Given the fundamental role that sleep plays in maintaining brain health through processes such as glymphatic clearance, sleep medicine has therapeutic potential beyond just sleep. Recent evidence suggests that sleep disruptions directly contribute to the build-up of pathological neuronal proteins in neurodegenerative disorders. Therefore, sleep medicine could improve prognosis in disorders such as these. Great attention must be paid to the mechanism of action of each sleep medicine, however, as sleep medicines which do not fully mimic sleep could actually worsen disease progression.
The DESTINIES Study: an online Delphi study to build international consensus on the medical conditions and procedures that confer immunosuppression and their respective COVID-19 risk profiles
Background: The lack of international consensus on defining and categorising immunosuppression has undermined disease surveillance and patient care, particularly during the COVID-19 pandemic. To address this, a global expert panel was recruited to join the eDElphi STudy to fully defiINe and COVID-risk stratify ImmunosupprESsion (DESTINIES) and develop a COVID risk-stratified digital phenotype for ‘adult immunosuppression’ (the DESTINIES phenotype). Methods: Panellists were presented with all medical diagnoses and procedures cited in prevailing immunosuppressed definitions; they evaluated their appropriateness for the DESTINIES phenotype and their risks for severe COVID-19 outcomes through anonymous online questionnaires and discussion. Panel agreement with a series of clinical statements were also assessed; statements incorporated longstanding disputes, including variables that could reverse immunosuppression. Each round of data collection informed and refined a draft phenotype until final ratification. This study was active between May and September 2024. Findings: Sixty-four experts from four continents and 12 international agencies completed two rounds of consensus questionnaire, a discussion group and ratifying vote. Panellists identified candidates posing higher (e.g. Transplantation, Primary Immunodeficiency) and lower COVID-19 risk (e.g. Anorexia nervosa, Cerebral spinal fluid leak) but disagreed on the categorisation of others (e.g. Asplenia, Immune-mediated Inflammatory Disease). Consensus was reached on ten clinical statements, notably removing Drug-managed HIV and Cancer remission from consideration as immunosuppressed. The DESTINIES phenotype was ratified with near unanimous support (94%) for implementation in surveillance. Interpretation: Pending validation, the DESTINIES phenotype provides a clinically meaningful, internationally ratified and digitally practical method for identifying and COVID-19 risk-stratifying adult immunosuppressed patients in healthcare data. Funding: This work was funded by the UK Medical Research Council and EMIS Health.
Cadê o Kauê? Co-design and acceptability testing of a chat-story aimed at enhancing youth participation in the promotion of mental health in Brazil.
BACKGROUND: Adolescent mental health is vital for public health, yet many interventions fail to recognise adolescents as proactive community contributors. This paper discusses the co-design and acceptability testing of a chat-story intervention to enhance Brazilian adolescents' participation in the promotion of mental health in their peer communities. We specifically highlight the iterative process of co-creating this intervention with community stakeholders. METHODS: The co-design was led by researchers, a youth collaborative group, and health-tech experts. Part 1 included quantitative (n = 1,768) and qualitative (n = 46) studies with Brazilian adolescents aged 15-18 for priority-setting. Part 2 involved co-creation and technical production, with input from youth advisors (n = 24), school staff (n = 11), and policy experts (n = 3). In Part 3, the chat-story was user tested (n = 32). Parts 4 and 5 assessed acceptability through a qualitative study in schools (n = 138) and initial efficacy during an online campaign (n = 795). RESULTS: Participants aspired to support their peers' mental health in schools, both one-to-one and collectively, but felt unprepared. This informed the chat-story's goal of enhancing peer support and collective action skills. Themes identified during Part 1, such as prejudice and academic pressure, were woven into the narrative to raise awareness of the social determinants of mental health, drawing from real-life stories. In the final story, players search for their missing best friend at school, uncovering his anxiety struggles and practicing skills such as empathic listening and partnership building. A manual for teachers was collaboratively designed for use within school settings, supplementing direct-to-user online applications. Acceptability testing showed participants found the tool authentic and user-friendly. Online users perceived the tool as preparing and motivating them to offer peer support and engage in collective action. CONCLUSIONS: The immersive co-creation model, enriched by input from key stakeholders, yielded a relevant and well-received intervention for Brazilian adolescents. Co-designed creative tools like chat-stories hold promise as digital mental health tools, fostering awareness, critical reflection, and inspiring adolescents to drive positive social change.
Redefining respiratory sinus arrhythmia as respiratory heart rate variability: an international Expert Recommendation for terminological clarity.
The variation of heart rate in phase with breathing, known as 'respiratory sinus arrhythmia' (RSA), is a physiological phenomenon present in all air-breathing vertebrates. RSA arises from the interaction of several physiological mechanisms but is primarily mediated by rhythmic changes in cardiac parasympathetic (vagal) activity, increasing heart rate during inspiration and decreasing heart rate during expiration. RSA amplitude is an indicator of autonomic and cardiac health; RSA is diminished or absent in common pathological conditions such as chronic heart failure and hypertension. In this Expert Recommendation, we argue that the term 'RSA', although historically important, is semantically inaccurate and carries misleading pathological connotations, contributing to misunderstanding and misinterpretation of the origin and the physiological importance of the phenomenon. We propose replacing 'RSA' with the term 'respiratory heart rate variability' (RespHRV), which avoids pathological connotations and emphasizes the specific respiratory contribution to heart rate variability. We clarify that RespHRV encompasses respiratory-related heart rate variations in both the low-frequency and high-frequency bands traditionally defined in heart rate variability analysis, and that its amplitude should not be misconstrued as a measure of vagal tone. Adopting the proposed term 'RespHRV' is expected to unify understanding and stimulate further experimental and clinical research into the physiological mechanisms and functional importance of this phenomenon.
Working memory filtering at encoding and maintenance in healthy ageing, Alzheimer's and Parkinson's disease.
The differential impact on working memory (WM) performance of distractors presented at encoding or during maintenance was investigated in Alzheimer's Disease (AD), Parkinson's Disease (PD) patients, elderly (EHC) and young healthy controls (YHC), (n = 28 per group). Participants reported the orientation of an arrow from a set of either two or three items, with a distractor present either at encoding or at maintenance. MRI data with hippocampal volumes was also acquired. Mean absolute error and mixture model metrics i.e., memory precision, target detection, misbinding (swapping the features of an object with another probed item) and guessing were computed. EHC and PD patients showed good filtering abilities both at encoding and maintenance. However, AD patients exhibited significant filtering deficits specifically when the distractor appeared during maintenance. In healthy ageing there was a prominent decline in WM memory precision, whilst in AD lower target detection and higher guessing were the main sources of error. Conversely, PD was associated only with higher guessing rates. Hippocampal volume was significantly correlated with filtering during maintenance - but not at encoding. These findings demonstrate how healthy ageing and neurodegenerative diseases exhibit distinct patterns of WM impairment, including when filtering irrelevant material either at encoding and maintenance.
Cholinergic degeneration in prodromal and early Parkinson's: a link to present and future disease states.
The neuropathological process in Parkinson's disease (PD) and Lewy body disorders has been shown to extend well beyond the degeneration of the dopaminergic system, affecting other neuromodulatory systems in the brain which play crucial roles in the clinical expression and progression of these disorders. Here, we investigate the role of the macrostructural integrity of the nucleus basalis of Meynert (NbM), the main source of cholinergic input to the cerebral cortex, in cognitive function, clinical manifestation, and disease progression in non-demented subjects with PD and individuals with isolated REM sleep behaviour disorder (iRBD). Using structural MRI data from 393 early PD patients, 128 iRBD patients, and 186 controls from two longitudinal cohorts, we found significantly lower NbM grey matter volume in both PD (β=-12.56, p=0.003) and iRBD (β=-16.41, p=0.004) compared to controls. In PD, higher NbM volume was associated with better higher-order cognitive function (β=0.10, p=0.045), decreased non-motor (β=-0.66, p=0.026) and motor (β=-1.44, p=0.023) symptom burden, and lower risk of future conversion to dementia (Hazard ratio (HR)<0.400, p<0.004). Higher NbM volume in iRBD was associated with decreased future risk of phenoconversion to PD or dementia with Lewy bodies (DLB) (HR<0.490, p<0.016). However, despite similar NbM volume deficits to those seen in PD, associations between NbM structural deficits and current disease burden or clinical state were less pronounced in iRBD. These findings identify NbM volume as a potential biomarker with dual utility: predicting cognitive decline and disease progression in early PD, while also serving as an early indicator of phenoconversion risk in prodromal disease. The presence of structural deficits before clear clinical correlates in iRBD suggests complex compensatory mechanisms may initially mask cholinergic dysfunction, with subsequent failure of these mechanisms potentially contributing to clinical conversion.
Designing better systems to navigate the sepsis-antimicrobial stewardship tension.
Sepsis is a leading cause of preventable death and requires timely antimicrobial treatment to reduce mortality. Despite extensive sepsis management guidelines, high-income countries continue to have considerable rates of sepsis mortality, indicating a gap between guideline quality, usability, and practical application. Simultaneously, the rise of antimicrobial resistance threatens the efficacy of antimicrobial therapies for infection control, underscoring the tension between sepsis management and antimicrobial stewardship. This Personal View explores how system factors, such as people, environments, tools, technologies, and tasks, influence the sepsis-antimicrobial stewardship tension. With the Systems Engineering Initiative for Patient Safety, we use a case study to highlight how organisational pressures, inadequate diagnostic tools, and sociocultural factors drive the gap between work-as-imagined and work-as-done. These latent safety risks that impede guideline adherence and contribute to unintended antimicrobial use highlight the need to design better systems, not blame individuals for non-compliance. We argue that addressing sepsis and antimicrobial resistance requires a holistic systems approach and that every discipline, including policy makers, clinicians, researchers, and drug developers, should adopt systems thinking in the design of interventions intended to address this problem. This shift is essential to ensuring effective care for patients today while safeguarding the effectiveness of antimicrobials tomorrow.
Automated quality control of T1-weighted brain MRI scans for clinical research: methods comparison and design of a quality prediction classifier
T1-weighted (T1w) MRI is widely used in clinical neuroimaging for studying brain structure and its changes, including those related to neurodegenerative diseases, and as anatomical reference for analysing other modalities. Ensuring high-quality T1w scans is vital as image quality affects reliability of outcome measures. However, visual inspection can be subjective and time-consuming, especially with large datasets. The effectiveness of automated quality control (QC) tools for clinical cohorts remains uncertain. In this study, we used T1w scans from elderly participants within ageing and clinical populations to test the accuracy of existing QC tools with respect to visual QC and to establish a new quality prediction framework for clinical research use. Four datasets acquired from multiple scanners and sites were used (N = 2438, 11 sites, 39 scanner manufacturer models, 3 field strengths – 1.5T, 3T, 2.9T, patients and controls, average age 71 ± 8 years). All structural T1w scans were processed with two standard automated QC pipelines (MRIQC and CAT12). The agreement of the accept-reject ratings was compared between the automated pipelines and with visual QC. We then designed a quality prediction framework that combines the QC measures from the existing automated tools and is trained on clinical research datasets. We tested the classifier performance using cross-validation on data from all sites together, also examining the performance across diagnostic groups. We then tested the generalisability of our approach when leaving one site out and explored how well our approach generalises to data from a different scanner manufacturer and/or field strength from those used for training, as well as on an unseen new dataset of healthy young participants with movement related artefacts. Our results show significant agreement between automated QC tools and visual QC (Kappa=0.30 with MRIQC predictions; Kappa=0.28 with CAT12’s rating) when considering the entire dataset, but the agreement was highly variable across datasets. Our proposed robust undersampling boost (RUS) classifier achieved 87.7% balanced accuracy on the test data combined from different sites (with 86.6% and 88.3% balanced accuracy on scans from patients and controls respectively). This classifier was also found to be generalisable on different combinations of training and test datasets (average balanced accuracy of leave-one-site-out = 78.2%; exploratory models on field strengths and manufacturers = 77.7%; movement related artefact dataset when including 1% scans in the training = 88.5%). While existing QC tools may not be robustly applicable to datasets comprised of older adults, they produce quality metrics that can be leveraged to train a more robust quality control classifiers for ageing and clinical cohorts.
FoxO1-zDHHC4-CD36 S-Acylation Axis Drives Metabolic Dysfunction in Diabetes.
BACKGROUND: The fatty acid (FA) transporter CD36 (FA translocase/cluster of differentiation 36) is the gatekeeper of cardiac FA metabolism. Preferential localization of CD36 to the sarcolemma is one of the initiating cellular responses in the development of muscle insulin resistance and the type 2 diabetic heart. Posttranslational S-acylation controls protein trafficking, and in this study, we hypothesized that increased CD36 S-acylation may underpin the preferential sarcolemmal localization of CD36, driving metabolic and contractile dysfunction in diabetes. METHODS AND RESULTS: Type 2 diabetes increased cardiac CD36 S-acylation, CD36 sarcolemmal localization, FA oxidation rates, and triglyceride storage in the diabetic heart. CD36 S-acylation was increased in diabetic rats, db/db mice, diabetic pigs, and insulin-resistant human iPSC-derived cardiomyocytes, demonstrating conservation between species. The enzyme responsible for S-acylating CD36, zDHHC4, was transcriptionally upregulated in the diabetic heart, and genetic silencing of zDHHC4 using siRNA or lentiviral shRNA decreased CD36 S-acylation. We identified that zDHHC4 expression is under the regulation of the transcription factor FoxO (forkhead box O) 1, as FoxO1 binds to the promotor of zDHHC4 and induces its transcription, as assessed using chromatin immunoprecipitation-seq, chromatin immunoprecipitation-quantitative PCR, luciferase assays, and siRNA silencing. Diabetic mice with cardiomyocyte-specific FoxO1 deletion had decreased cardiac zDHHC4 expression and decreased CD36 S-acylation, which was further confirmed using diabetic mice treated with the FoxO1 inhibitor AS1842856. Pharmacological inhibition of zDHHC enzymes in diabetic hearts decreased CD36 S-acylation, sarcolemmal CD36 content, FA oxidation rates, and triglyceride storage, culminating in improved cardiac function in diabetes. Conversely, inhibiting the deacylating enzymes in control hearts increased CD36 S-acylation, sarcolemmal CD36 content, and FA metabolic rates in control hearts, recapitulating the metabolic phenotype seen in diabetic hearts. CONCLUSIONS: Activation of the FoxO1-zDHHC4-CD36 S-acylation axis in diabetes drives metabolic and contractile dysfunction in type 2 diabetic heart.
Loss of the NF-κB negative regulator Pirk in Drosophila links brain and gut immunity to neurodegeneration
A gut-brain axis influenced by host innate immunity and resident microbiota has been implicated in neurological conditions including Alzheimer's disease. However, the precise connection of innate immunity to Alzheimer's disease remains unclear. Using Pirk, a negative regulator of the IMD/NF-κB pathway in Drosophila, we studied the neurological phenotypes induced when genetically predisposing flies to chronically over-active immunity. Pirk mutants exhibited age-dependent neurological phenotypes such as reduced locomotion and altered sleep patterns coupled to an increased number of brain lesions. Gut-specific pirk-RNA interference led to earlier onset of the neurological phenotypes which, alongside changes in intestinal bacteria in pirk mutants, highlighted a potential early role for the intestinal ecosystem in the onset of neurodegeneration. In contrast, glia-specific RNA interference of pirk resulted in late onset of the relevant phenotypes suggesting a later contribution of the nervous system to the underlying neuropathology. Knockout of the antimicrobial peptide (AMP) gene AttacinD or rearing flies in axenic conditions recovered some of the neurological phenotypes, suggesting both chronic AMP gene expression as well as gut bacteria changes as mediators. Our results indicate an evolutionarily conserved path to neurodegeneration linked to dysregulated immunity. They also reveal that in this context, age-dependent neurodegeneration can happen in less complex non-vertebrate brains in the absence of beta-amyloid or tau aggregation.
Smad4 and TGFβ1 dependent gene expression signatures in conditional intestinal adenoma, organoids and colorectal cancer.
TGF-β ligands suppress growth yet can paradoxically and potently promote cancer invasion and metastasis depending on downstream pathway mutational context, such as loss of Mothers against decapentaplegic homolog 4 (Smad4). Here, we characterised phenotypes and associated gene expression signatures in conditional murine intestinal adenoma with and without Smad4. Conditional Lgr5-CreERT2 activation in Apcfl/flSmad4fl/fl mice resulted in homozygote floxed alleles (ApcΔ/ΔSmad4Δ/Δ) and adenoma formation. The adenoma phenotype was discordant, with reduced small intestinal adenoma burden yet development of large non-metastatic caecal adenoma with nuclear localisation of phospho-Smad2/3. Derived ApcΔ/ΔSmad4Δ/Δ adenoma organoids resisted TGF-β1 dose dependent growth arrest and cell death (IC50 534 pM) compared to ApcΔ/ΔSmad4+/+ (IC50 24 pM). TGF-β1 (390 pM) altered adenoma bulk mRNA expression most significantly for Id1low and Spp1high in ApcΔ/ΔSmad4Δ/Δ. Single cell RNAseq of caecal adenoma identified expansion of Lgr5low, Pak3high and Id1low progenitor populations in ApcΔ/ΔSmad4Δ/Δ. Of the 76 Smad4 and TGF-β1 dependent genes identified in Apcfl/flSmad4fl/fl adenoma organoids, only 7 human equivalent genes were differentially expressed in SMAD4 mutated colorectal cancer (TCGA cohorts), including ID1low. SMAD4low, ID1low SPP1high and PAK3high all correlated with poorer survival. Murine adenoma identified Smad4 dependent gene expression signatures that require further evaluation as functional biomarker classifiers of SMAD4 mutated cancer subtypes.