Interleukin-2-mediated CD4 T-cell activation correlates highly with effective serological and T-cell responses to SARS-CoV-2 vaccination in people living with HIV.

People living with HIV (PLWH) despite having an appreciable depletion of CD4+ T-cells show a good severe acute respiratory syndrome coronavirus 2 vaccination response. The underlying mechanism(s) are currently not understood. We studied serological and polyfunctional T-cell responses in PLWH receiving anti-retroviral therapy stratified on CD4+ counts as PLWH-high (CD4 ≥ 500 cells/mm3) and PLWH-low (<500 cells/mm3). Responses were assessed longitudinally before the first vaccination (T0), 1-month after the first dose (T1), 3-months (T2), and 6-months (T3) after the second dose. Expectedly, both PLWH-high and -low groups developed similar serological responses after T2, which were also non-significantly different from age and vaccination-matched HIV-negative controls at T3. The immunoglobulin G titers were also protective showing a good correlation with angiotensin-converting enzyme 2-neutralizations (R = 0.628, p = 0.005). While surface and intracellular activation analysis showed no significant difference at T3 between PLWH and controls in activated CD4+CD154+ and CD4+ memory T-cells, spike-specific CD4+ polyfunctional cytokine expression analysis showed that PLWH preferentially express interleukin (IL)-2 (p < 0.001) and controls, interferon-γ (p = 0.017). CD4+ T-cell counts negatively correlated with IL-2-expressing CD4+ T-cells including CD4+ memory T-cells (Spearman ρ: -0.85 and -0.80, respectively; p < 0.001). Our results suggest that the durable serological and CD4+ T-cell responses developing in vaccinated PLWH are associated with IL-2-mediated CD4+ T-cell activation that likely compensates for CD4+ T-cell depletion in PLWH.

High sera levels of SARS-CoV-2 N antigen are associated with death in hospitalized COVID-19 patients.

The presence of free severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid-antigen in sera (N-antigenemia) has been shown in COVID-19 patients. However, the link between the quantitative levels of N-antigenemia and COVID-19 disease severity is not entirely understood. To assess the dynamics and clinical association of N-antigen sera levels with disease severity in COVID-19 patients, we analyzed data from patients included in the French COVID cohort, with at least one sera sample between January and September 2020. We assessed N-antigenemia levels and anti-N IgG titers, and patient outcomes was classified in two groups, survival or death. In samples collected within 8 days since symptom onset, we observed that deceased patients had a higher positivity rate (93% vs. 81%; p < 0.001) and higher median levels of predicted N-antigenemia (2500 vs. 1200 pg/mL; p < 0.001) than surviving patients. Predicted time to N-antigen clearance in sera was prolonged in deceased patients compared to survivors (23.3 vs 19.3 days; p < 0.0001). In a subset of patients with both sera and nasopharyngeal (NP) swabs, predicted time to N-antigen clearance in sera was prolonged in deceased patients (p < 0.001), whereas NP viral load clearance did not differ between the groups (p = 0.07). Our results demonstrate a strong relationship between N-antigenemia levels and COVID-19 severity on a prospective cohort.

Susceptibility profiles and resistance genomics of Pseudomonas aeruginosa isolates from European ICUs participating in the ASPIRE-ICU trial.

OBJECTIVES: To determine the susceptibility profiles and the resistome of Pseudomonas aeruginosa isolates from European ICUs during a prospective cohort study (ASPIRE-ICU). METHODS: 723 isolates from respiratory samples or perianal swabs of 402 patients from 29 sites in 11 countries were studied. MICs of 12 antibiotics were determined by broth microdilution. Horizontally acquired ß-lactamases were analysed through phenotypic and genetic assays. The first respiratory isolates from 105 patients providing such samples were analysed through WGS, including the analysis of the resistome and a previously defined genotypic resistance score. Spontaneous mutant frequencies and the genetic basis of hypermutation were assessed. RESULTS: All agents except colistin showed resistance rates above 20%, including ceftolozane/tazobactam and ceftazidime/avibactam. 24.9% of the isolates were XDR, with a wide intercountry variation (0%-62.5%). 13.2% of the isolates were classified as DTR (difficult-to-treat resistance). 21.4% of the isolates produced ESBLs (mostly PER-1) or carbapenemases (mostly NDM-1, VIM-1/2 and GES-5). WGS showed that these determinants were linked to high-risk clones (particularly ST235 and ST654). WGS revealed a wide repertoire of mutation-driven resistance mechanisms, with multiple lineage-specific mutations. The most frequently mutated genes were gyrA, parC, oprD, mexZ, nalD and parS, but only two of the isolates were hypermutable. Finally, a good accuracy of the genotypic score to predict susceptibility (91%-100%) and resistance (94%-100%) was documented. CONCLUSIONS: An overall high prevalence of resistance is documented European ICUs, but with a wide intercountry variability determined by the dissemination of XDR high-risk clones, arguing for the need to reinforce infection control measures.

Subtle vascular and astrocytic changes in the brain of coronavirus disease 2019 (COVID-19) patients.

BACKGROUND AND PURPOSE: In the central nervous system, a multitude of changes have been described associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, such as microglial activation, perivascular lymphocyte cuffing, hypoxic-ischaemic changes, microthrombosis, infarcts or haemorrhages. It was sought here to assess the vascular basement membranes (vBMs) and surrounding perivascular astrocytes for any morphological changes in acute respiratory syndrome (coronavirus disease 2019, COVID-19) patients. METHODS: The light microscopy morphology of the vBMs and perivascular astrocytes from brains of 14 patients with confirmed SARS-CoV-2 infection was analysed and compared to four control patients utilizing fluorescent immunohistochemistry for collagen IV and astrocytes (GFAP), endothelia (CD31), tight junction 1 (TJ1) adhesion protein, as well as the aquaporin 4 (AQP4) water channel. On 2D and 3D deconvoluted images from the cortex and white matter, vessel densities, diameters, degree of gliosis, collagen IV/GFAP and GFAP/AQP4 colocalizations were calculated, as well as the fractal dimension of astrocytes and vBMs viewed in tangential planes. RESULTS: Fractal dimension analysis of the GFAP-stained astrocytes revealed lower branching complexities and decreased GFAP/collagen IV colocalization for COVID-19 patients. Interestingly, vBMs showed significantly increased irregularities (fractal dimension values) compared to controls. Vessel diameters were increased in COVID-19 cases, especially for the white matter, TJ1 protein decreased its colocalization with the endothelia, and AQP4 reduced its co-expression in astrocytes. CONCLUSIONS: Our data on the irregularity of the basement membranes, loss of endothelial tight junction, reduction of the astrocyte end-feet and decrease of AQP4 suggest subtle morphological changes of the blood-brain barrier in COVID-19 brains that could be linked with indirect inflammatory signalling or hypoxia/hypercapnia.

Clinical efficacy of different monoclonal antibody regimens among non-hospitalised patients with mild to moderate COVID-19 at high risk for disease progression: a prospective cohort study.

This study aimed to compare the clinical progression of COVID-19 in high-risk outpatients treated with the monoclonal antibodies (mAb) bamlanivimab, bamlanivimab-etesevimab and casirivimab-imdevimab. This is an observational, multi-centre, prospective study conducted from 18 March to 15 July 2021 in eight Italian tertiary-care hospitals including mild-to-moderate COVID-19 outpatients receiving bamlanivimab (700 mg), bamlanivimab-etesevimab (700-1400 mg) or casirivimab-imdevimab (1200-1200 mg). All patients were at high risk of COVID-19 progression according to Italian Medicines Agency definitions. In a patient subgroup, SARS-CoV-2 variant and anti-SARS-CoV-2 serology were analysed at baseline. Factors associated with 28-day all-cause hospitalisation were identified using multivariable multilevel logistic regression (MMLR) and summarised with adjusted odds ratio (aOR) and 95% confidence interval (CI). A total of 635 outpatients received mAb: 161 (25.4%) bamlanivimab, 396 (62.4%) bamlanivimab-etesevimab and 78 (12.2%) casirivimab-imdevimab. Ninety-five (15%) patients received full or partial SARS-CoV-2 vaccination. The B.1.1.7 (Alpha) variant was detected in 99% of patients. Baseline serology showed no significant differences among the three mAb regimen groups. Twenty-eight-day all-cause hospitalisation was 11.3%, with a significantly higher proportion (p 0.001) in the bamlanivimab group (18.6%), compared to the bamlanivimab-etesevimab (10.1%) and casirivimab-imdevimab (2.6%) groups. On MMLR, aORs for 28-day all-cause hospitalisation were significantly lower in patients receiving bamlanivimab-etesevimab (aOR 0.51, 95% CI 0.30-0.88 p 0.015) and casirivimab-imdevimab (aOR 0.14, 95% CI 0.03-0.61, p 0.009) compared to those receiving bamlanivimab. No patients with a history of vaccination were hospitalised. The study suggests differences in clinical outcomes among the first available mAb regimens for treating high-risk COVID-19 outpatients. Randomised trials are needed to compare efficacy of mAb combination regimens in high-risk populations and according to circulating variants.

Mechanical Ventilation Impairs IL-17 Cytokine Family Expression in Ventilator-Associated Pneumonia.

Mechanical ventilation (MV) is the primary risk factor for the development of ventilator-associated pneumonia (VAP). Besides inducing a pro-inflammatory T-helper (Th)-1 cytokine response, MV also induces an anti-inflammatory Th2 cytokine response, marked by increased IL-4 secretion and reduced bacterial phagocytic capacity of rodent lung macrophages. Since IL-4 is known to downregulate both Th1 and Th17 cytokines, the latter is important in mediating mucosal immunity and combating bacterial and fungal growth, we studied and showed here in a rat model of MV that Th17 cytokines (IL-17A, IL-17F, and IL-22) were significantly upregulated in the lung as a response to different MV strategies currently utilized in clinic. To study whether the increased IL-4 levels are associated with downregulation of the anti-bacterial Th17 cytokines, we subsequently challenged mechanically ventilated rats with an intratracheal inoculation of Pseudomonas aeruginosa (VAP model) and showed a dramatic downregulation of IL-17A, IL-17F, and IL-22, compared to animals receiving the same bacterial burden without MV. For the studied Th1 cytokines (IFN, TNF, IL-6, and IL-1), only IFN showed a significant decrease as a consequence of bacterial infection in mechanically ventilated rats. We further studied IL-17A, the most studied IL-17 family member, in intensive care unit (ICU) pneumonia patients and showed that VAP patients had significantly lower levels of IL-17A in the endotracheal aspirate compared to patients entering ICU with pre-existing pneumonia. These translational data, obtained both in animal models and in humans, suggest that a deficient anti-bacterial Th17 response in the lung during MV is associated with VAP development.

Mechanical Ventilation Induces Interleukin 4 Secretion in Lungs and Reduces the Phagocytic Capacity of Lung Macrophages.

Patients receiving mechanical ventilation are at risk of developing ventilator-associated pneumonia. Here, we show that clinically utilized ventilation protocols in rats with 5 mL/kg or 8 mL/kg tidal volumes cause increased interleukin 4 (IL-4) expression, lowered ratio of TH1:TH2 transcriptional factors (Tbet:Gata3), and increased arginase 1-positive (Arg1+) macrophages and eosinophils in lungs. Macrophages from ventilated lungs had reduced ex vivo capacity toward phagocytosing bacteria. Ventilated animals, when further challenged with bacterial pneumonia, continued to show persistence of Arg1+ M2 macrophages as well as an increased bacterial burden compared with spontaneously breathing animals receiving the same bacterial dose. Increased IL-4 expression also occurred in a mouse ventilation model, and abrogation of IL-4 signaling restored lung bacterial burden in an IL-4Rα-/- ventilator-associated pneumonia model. Our data suggest that mechanical ventilation induces an immunosuppressive state in lungs, providing new insight in the development of ventilator-associated pneumonia.

Proposal for assignment of allele numbers for mobile colistin resistance (mcr) genes.

The initial report of the mcr-1 (mobile colistin resistance) gene has led to many reports of mcr-1 variants and other mcr genes from different bacterial species originating from human, animal and environmental samples in different geographical locations. Resistance gene nomenclature is complex and unfortunately problems such as different names being used for the same gene/protein or the same name being used for different genes/proteins are not uncommon. Registries exist for some families, such as bla (ß-lactamase) genes, but there is as yet no agreed nomenclature scheme for mcr genes. The National Center for Biotechnology Information (NCBI) recently took over assigning bla allele numbers from the longstanding Lahey ß-lactamase website and has agreed to do the same for mcr genes. Here, we propose a nomenclature scheme that we hope will be acceptable to researchers in this area and that will reduce future confusion.

Consolidating and Exploring Antibiotic Resistance Gene Data Resources.

The unrestricted use of antibiotics has resulted in rapid acquisition of antibiotic resistance (AR) and spread of multidrug-resistant (MDR) bacterial pathogens. With the advent of next-generation sequencing technologies and their application in understanding MDR pathogen dynamics, it has become imperative to unify AR gene data resources for easy accessibility for researchers. However, due to the absence of a centralized platform for AR gene resources, availability, consistency, and accuracy of information vary considerably across different databases. In this article, we explore existing AR gene data resources in order to make them more visible to the clinical microbiology community, to identify their limitations, and to propose potential solutions.

Identification of a novel plasmid-mediated colistin-resistance gene, mcr-2, in Escherichia coli, Belgium, June 2016.

We identified a novel plasmid-mediated colistin-resistance gene in porcine and bovine colistin-resistant Escherichia coli that did not contain mcr-1. The gene, termed mcr-2, a 1,617 bp phosphoethanolamine transferase harboured on an IncX4 plasmid, has 76.7% nucleotide identity to mcr-1. Prevalence of mcr-2 in porcine colistin-resistant E. coli (11/53) in Belgium was higher than that of mcr-1 (7/53). These data call for an immediate introduction of mcr-2 screening in ongoing molecular epidemiological surveillance of colistin-resistant Gram-negative pathogens.

Cardiac Output Assessment by Transthoracic Electrical Bio-impedance in Patients of Acute Myocardial Infarction: Comparative Analysis with Echocardiography.

Objectives: Transthoracic electrical bio-impedance (TEB) has been proposed as a non-invasive and continuous method of cardiac output (CO) measurement, but it still has not found wide usages in clinics. The present study measured CO, using a new instrument NICOMON, and compared it with Echocardiography (ECHO) in acute myocardial infarction (AMI) patients. Methods: In the present study 100 patients of AMI were assessed by both ECHO and NICOMON for cardiac output and ECHO is considered as a reference method for comparison. TEB CO was measured by passing an alternating current and measuring the bio-impedance across the thorax. End diastolic volume (EDV), End systolic volume (ESV) & Left ventricular outflow tract (LVOT) diameter, measured by ECHO were used to calculate CO. Various statistical methods like "t"-test & correlation coefficient (r) were used where found suitable. Results: Results: Mean TEB-CO (4.03±1.11 l/min) was significantly higher (p<0.001) than mean ECHO-CO (3.80±1.28 l/min) with a mean difference of 0.25±1.02 l/min. Conclusions: NICOMON measures CO non-invasively but, it needs more elaborative studies on a larger sample to establish it as an alternative method of ECHO for cardiac output measurement on regular basis.

Brain inflammation in a chronic epilepsy model: Evolving pattern of the translocator protein during epileptogenesis.

AIMS: A hallmark in the neuropathology of temporal lobe epilepsy is brain inflammation which has been suggested as both a biomarker and a new mechanistic target for treatments. The translocator protein (TSPO), due to its high upregulation under neuroinflammatory conditions and the availability of selective PET tracers, is a candidate target. An important step to exploit this target is a thorough characterisation of the spatiotemporal profile of TSPO during epileptogenesis. METHODS: TSPO expression, microglial activation, astrocyte reactivity and cell loss in several brain regions were evaluated at five time points during epileptogenesis, including the chronic epilepsy phase in the kainic acid-induced status epilepticus (KASE) model (n = 52) and control Wistar Han rats (n = 33). Seizure burden was also determined in the chronic phase. Furthermore, ¹8F-PBR111 PET/MRI scans were acquired longitudinally in an additional four KASE animals. RESULTS: TSPO expression measured with in vitro and in vivo techniques was significantly increased at each time point and peaked two weeks post-SE in the limbic system. A prominent association between TSPO expression and activated microglia (p < 0.001; r = 0.7), as well as cell loss (p < 0.001; r = -0.8) could be demonstrated. There was a significant positive correlation between spontaneous seizures and TSPO upregulation in several brain regions with increased TSPO expression. CONCLUSIONS: TSPO expression was dynamically upregulated during epileptogenesis, persisted in the chronic phase and correlated with microglia activation rather than reactive astrocytes. TSPO expression was correlating with spontaneous seizures and its high expression during the latent phase might possibly suggest being an important switching point in disease ontogenesis which could be further investigated by PET imaging.

Assessing the Brainstem Auditory Evoked Potentials in Subjects with Family History of Hypertension.

Background: Hypertension (HTN) has a genetic predisposition and it also impairs microcirculation, thereby, affecting the well vascularized structures like the brainstem and causing changes in Brainstem Auditory Evoked Potentials (BAEPs). Purpose: To find out the usefulness of BAEPs as a screening tool in apparently healthy individuals with a family history of HTN. Methods: One hundred and ten volunteers, aged 17 to 23 years, were enrolled in the study as participants with proper consent. After excluding the subjects with existing diseases or co-morbidities (e.g. diabetes, HTN, schizophrenia, neuropathy, etc.), those on ototoxic or neurotoxic drugs, a preliminary physical examination was performed, following which BAEPs were recorded with a proper device. Statistical analysis is done with SPSS 2016 software using the chi-square test. Results: A consistent distortion in the inter-peak latency of III-V waves is noted when a family history of HTN is present in either parent or maternal grandparents. Other statistically significant findings are present in V/I% (HTN in mother), wave I (HTN in paternal grandfather), wave III (HTN in maternal grandfather), and inter-peak latency I-V (HTN in maternal grandmother). Conclusion: BAEP may be used as a screening tool in individuals with a family history of HTN with supportive evidence from further studies in the near future.

Fractal Analysis in Neurodegenerative Diseases.

Neurodegenerative diseases are defined by progressive nervous system dysfunction and death of neurons. The abnormal conformation and assembly of proteins is suggested to be the most probable cause for many of these neurodegenerative disorders, leading to the accumulation of abnormally aggregated proteins, for example, amyloid ß (Aß) (Alzheimer's disease and vascular dementia), tau protein (Alzheimer's disease and frontotemporal lobar degeneration), α-synuclein (Parkinson's disease and Lewy body dementia), polyglutamine expansion diseases (Huntington disease), or prion proteins (Creutzfeldt-Jakob disease). An aberrant gain-of-function mechanism toward excessive intraparenchymal accumulation thus represents a common pathogenic denominator in all these proteinopathies. Moreover, depending upon the predominant brain area involvement, these different neurodegenerative diseases lead to either movement disorders or dementia syndromes, although the underlying mechanism(s) can sometimes be very similar, and on other occasions, clinically similar syndromes can have quite distinct pathologies. Non-Euclidean image analysis approaches such as fractal dimension (FD) analysis have been applied extensively in quantifying highly variable morphopathological patterns, as well as many other connected biological processes; however, their application to understand and link abnormal proteinaceous depositions to other clinical and pathological features composing these syndromes is yet to be clarified. Thus, this short review aims to present the most important applications of FD in investigating the clinical-pathological spectrum of neurodegenerative diseases.

Cytokine Expression in Cancer Survivors Suffering From Chronic Pain: A Systematic Review.

BACKGROUND: Chronic cancer-related pain remains underdiagnosed and undertreated, although it affects 40% of cancer survivors. Recent insights suggest that cytokine signaling between immune, neuro, and glial cells contributes to chronic pain. OBJECTIVES: This study systematically reviewed cytokine levels and their relation to chronic cancer-related pain and, additionally, investigated differences in cytokine levels between cancer survivors with and without chronic pain. STUDY DESIGN: Systematic review. METHODS: This systematic review was conducted and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines (PRISMA). The study conducted a systematic literature search in the databases PubMed, Web of Science, and Embase for articles examining cytokine levels and pain experience at a time point of a minimum of 3 months post-cancer diagnosis. Pain experience was categorized into a total pain score, pain intensity, and pain interference. The risk of bias was assessed using the Newcastle Ottawa Scale. RESULTS: Eight articles were included, investigating 6 cancer types and 30 cytokines. Moderate evidence was found for pro-inflammatory cytokine IL-6 to be correlated with pain intensity, of which higher levels are observed in cancer survivors experiencing chronic pain compared to pain-free survivors. Moderate evidence was found for TNF-alpha to be not correlated with any pain experience, which is similar for anti-inflammatory cytokines IL-8 and IL-10 with pain intensity. For the remaining 26 cytokines and pain outcomes, only limited evidence was found for an association or alteration. LIMITATIONS: The number of included studies was small. Overall, studies showed a moderate risk of bias, except one indicated a high risk of bias. CONCLUSION: More standardized post-cancer treatment studies are warranted to confirm these results and explore associations and alterations of other cytokines. Nonetheless, moderate evidence suggests that elevated levels of IL-6, in contrast with TNF-alpha levels, are correlated with pain intensity in cancer survivors experiencing chronic pain compared to pain-free survivors.

Mrgprb2-dependent Mast Cell Activation Plays a Crucial Role in Acute Colitis.

BACKGROUND & AIMS: Mast cells (MCs) are typically found at mucosal surfaces, where their immunoglobulin E (IgE)-dependent activation plays a central role in allergic diseases. Over the past years, signaling through Mas-related G protein-coupled receptor b2 (Mrgprb2) in mice and MRGPRX2 in humans has gained a lot of interest as an alternative MC activation pathway with high therapeutic potential. The aim of this study was to explore the relevance of such IgE-independent, Mrgprb2-mediated signaling in colonic MCs in the healthy and acutely inflamed mouse colon. METHODS: Mrgprb2 expression and functionality was studied using a genetic labeling strategy combined with advanced microscopic imaging. Furthermore, Mrgprb2 knockout (Mrgprb2-/-) mice were used to determine the role of this pathway in a preclinical dextran sodium sulphate (DSS) colitis model. RESULTS: We found that Mrgprb2 acts as a novel MC degranulation pathway in a large subset of connective tissue MCs in the mouse distal colon. Acute DSS colitis induced a pronounced increase of Mrgprb2-expressing MCs, which were found in close association with Substance P-positive nerve fibers. Loss of Mrgprb2-mediated signaling impaired DSS-induced neutrophil influx and significantly impacted on acute colitis progression. CONCLUSIONS: Our findings uncover a novel, IgE-independent MC degranulation pathway in the mouse colon that plays a central role in acute colitis pathophysiology, mainly by safeguarding acute colitis progression and severity in mice. This pseudo allergic, Mrgprb2-induced signaling is part of a hitherto unconsidered colonic neuro-immune pathway and might have significant potential for the further development of effective therapeutic treatment strategies for gastrointestinal disorders, such as ulcerative colitis.

Chemosensory assessment and impact on quality of life in neurosensorial cluster of the post COVID 19 syndrome.

COVID-19 pandemic brought chemosensory impairment to the forefront of medicine, revealing gaps in the knowledge of pathophysiological mechanisms, true prevalence and preventive/therapeutic alternatives. This is a sub-study of the ORCHESTRA cohort focusing on post-COVID-19 chemosensory symptoms. Risk factors for neurosensorial cluster of post-COVID-19 syndrome (NSc-PCS) were assessed through multivariable analysis. Psychophysical validated tests were applied on a sub-population of 50 patients. Qualitative chemosensory symptoms as well as nasal and oral chemesthesis were evaluated through anamnestic interview and the quality of life through the SF-36 questionnaire. Chemosensory symptoms evolution and olfactory training's outcome were assessed through phone-call interviews. Out of 1187 patients (female, N = 630), 550 (47%) presented NSc-PCS, with a lower risk for older age and monoclonal antibodies treatment, and a higher risk in females (p < 0.001). Out of the 50 patients evaluated with psychophysical tests, 66% showed smell reduction with a qualitative alteration in 50% of hyposmic and 35% of normosmic patients. Hypogeusia was present in 14 (28%) of the patients assessed, with 56% showing a qualitative alteration; 53% of normogeusic patients presented qualitative disorders. NSc-PCS has a complex, fluctuating, multifaceted presentation. Quantifying and characterizing COVID-19-related chemosensory impairment is key to understand underlying mechanisms and to develop preventive and therapeutic treatment.

The natural history of CVB3 myocarditis in C57BL/6J mice: an extended in-depth characterization.

BACKGROUND AND AIMS: Viral infections are the leading cause of myocarditis. Besides acute cardiac complications, late-stage sequelae such as myocardial fibrosis may develop, importantly impacting the prognosis. Coxsackievirus B3 (CVB)-induced myocarditis in mice is the most commonly used translational model to study viral myocarditis and has provided the majority of our current understanding of the disease pathophysiology. Nevertheless, the late stages of disease, encompassing fibrogenesis and arrhythmogenesis, have been underappreciated in viral myocarditis research to date. The present study investigated the natural history of CVB-induced myocarditis in C57BL/6J mice, expanding the focus beyond the acute phase of disease. In addition, we studied the impact of sex and inoculation dose on the disease course. METHODS AND RESULTS: C57BL/6J mice (12 weeks old; n=154) received a single intraperitoneal injection with CVB to induce viral myocarditis, or vehicle (PBS) as control. Male mice (n=92) were injected with 5 × 105 (regular dose) (RD) or 5 × 106 (high dose) (HD) plaque-forming units of CVB, whereas female mice received the RD only. Animals were sacrificed 1, 2, 4, 8, and 11 weeks after CVB or PBS injection. Virally inoculated mice developed viral disease with a temporary decline in general condition and weight loss, which was less pronounced in female animals (P<.001). In male CVB mice, premature mortality occurred between days 8 and 23 after inoculation (RD: 21%, HD: 20%), whereas all female animals survived. Over the course of disease, cardiac inflammation progressively subsided, with faster resolution in female mice. There were no substantial group differences in the composition of the inflammatory cell infiltrates: predominance of cytotoxic T cells at day 7 and 14, and a switch from arginase1-reactive macrophages to iNOS-reactive macrophages from day 7 to 14 were the main findings. There was concomitant development and maturation of different patterns of myocardial fibrosis, with enhanced fibrogenesis in male mice. Virus was almost completely cleared from the heart by day 14. Serum biomarkers of cardiac damage and cardiac expression of remodeling genes were temporarily elevated during the acute phase of disease. Cardiac CTGF gene upregulation was less prolonged in female CVB animals. In vivo electrophysiology studies at weeks 8 and 11 demonstrated that under baseline conditions (i.e. in the absence of proarrhythmogenic drugs), ventricular arrhythmias could only be induced in CVB animals. The cumulative arrhythmia burden throughout the entire stimulation protocol was not significantly different between CVB and control groups. CONCLUSION: CVB inoculation in C57BL/6J mice represents a model of acute self-limiting viral myocarditis, with progression to different patterns of myocardial fibrosis. Sex, but not inoculation dose, seems to modulate the course of disease.

Immunogenicity, reactogenicity, and safety of a second booster with BNT162b2 or full-dose mRNA-1273: A randomized VACCELERATE trial in adults aged ≥75 years (EU-COVAT-1-AGED Part B).

OBJECTIVES: To assess the safety and immunogenicity of a fourth vaccination (second booster) in individuals aged ≥75 years. METHODS: Participants were randomized to BNT162b2 (Comirnaty, 30 µg) or messenger RNA (mRNA)-1273 (Spikevax, 100 µg). The primary end point was the rate of two-fold antibody titer increase 14 days after vaccination, targeting the receptor binding domain (RBD) region of wild-type SARS-CoV-2. The secondary end points included changes in neutralizing activity against wild-type and 25 variants. Safety was assessed by monitoring solicited adverse events (AEs) for 7 days. RESULTS: A total of 269 participants (mean age 81 years, mRNA-1273 n = 135/BNT162b2 n = 134) were included. Two-fold anti-RBD immunoglobulin (Ig) G titer increase was achieved by 101 of 129 (78%) and 116 of 133 (87%) subjects in the BNT162b2 and the mRNA-1273 group, respectively (P = 0.054). A second booster of mRNA-1273 provided higher anti-RBD IgG geometric mean titer: 21.326 IU/mL (95% confidence interval: 18.235-24.940) vs BNT162b2: 15.181 IU/mL (95% confidence interval: 13.172-17.497). A higher neutralizing activity was noted for the mRNA-1273 group. The most frequent AE was pain at the injection site (51% in mRNA-1273 and 48% in BNT162b2). Participants in the mRNA-1273 group had less vaccine-related AEs (30% vs 39%). CONCLUSIONS: A second booster of either BNT162b2 or mRNA-1273 provided substantial IgG increase. Full-dose mRNA-1273 provided higher IgG levels and neutralizing capacity against SARS-CoV-2, with similar safety profile for subjects of advanced age.

Cellular ageing, increased mortality and FTLD-TDP-associated neuropathology in progranulin knockout mice.

Loss-of-function mutations in progranulin (GRN) are associated with frontotemporal lobar degeneration with intraneuronal ubiquitinated protein accumulations composed primarily of hyperphosphorylated TDP-43 (FTLD-TDP). The mechanism by which GRN deficiency causes TDP-43 pathology or neurodegeneration remains elusive. To explore the role of GRN in vivo, we established Grn knockout mice using a targeted genomic recombination approach and Cre-LoxP technology. Constitutive Grn homozygous knockout (Grn(-/-) ) mice were born in an expected Mendelian pattern of inheritance and showed no phenotypic alterations compared to heterozygous (Grn(+/-) ) or wild-type (Wt) littermates until 10 months of age. From then, Grn(-/-) mice showed reduced survival accompanied by significantly increased gliosis and ubiquitin-positive accumulations in the cortex, hippocampus, and subcortical regions. Although phosphorylated TDP-43 could not be detected in the ubiquitinated inclusions, elevated levels of hyperphosphorylated full-length TDP-43 were recovered from detergent-insoluble brain fractions of Grn(-/-) mice. Phosphorylated TDP-43 increased with age and was primarily extracted from the nuclear fraction. Grn(-/-) mice also showed degenerative liver changes and cathepsin D-positive foamy histiocytes within sinusoids, suggesting widespread defects in lysosomal turnover. An increase in insulin-like growth factor (IGF)-1 was observed in Grn(-/-) brains, and increased IGF-1 signalling has been associated with decreased longevity. Our data suggest that progranulin deficiency in mice leads to reduced survival in adulthood and increased cellular ageing accompanied by hyperphosphorylation of TDP-43, and recapitulates key aspects of FTLD-TDP neuropathology.