A pro-inflammatory gut mucosal cytokine response is associated with mild COVID-19 disease and superior induction of serum antibodies

The relationship between gastrointestinal tract infection, the host immune response, and the clinical outcome of disease is not well understood in COVID-19. We sought to understand the effect of intestinal immune responses to SARS-CoV-2 on patient outcomes including the magnitude of systemic antibody induction. Combining two prospective cohort studies, International Severe Acute Respiratory and emerging Infections Consortium Comprehensive Clinical Characterisations Collaboration (ISARIC4C) and Integrated Network for Surveillance, Trials and Investigations into COVID-19 Transmission (INSTINCT), we acquired samples from 88 COVID-19 cases representing the full spectrum of disease severity and analysed viral RNA and host gut cytokine responses in the context of clinical and virological outcome measures. There was no correlation between the upper respiratory tract and faecal viral loads. Using hierarchical clustering, we identified a group of fecal cytokines including Interleukin-17A, Granulocyte macrophage colony-stimulating factor, Tumor necrosis factorα, Interleukin-23, and S100A8, that were transiently elevated in mild cases and also correlated with the magnitude of systemic anti-Spike-receptor-binding domain antibody induction. Receiver operating characteristic curve analysis showed that expression of these gut cytokines at study enrolment in hospitalised COVID-19 cases was associated negatively with overall clinical severity implicating a protective role in COVID-19. This suggests that a productive intestinal immune response may be beneficial in the response to a respiratory pathogen and a biomarker of a successful barrier response.

Preliminary evidence for the acceptability, safety, and efficacy of the flash technique

Objectives

This study reports on four similar studies intended to explore the acceptability, safety, and efficacy of the flash technique (FT), a method of rapidly reducing the intensity of a disturbing memory or image, with minimal subjective disturbance for subjects during the process. Of the four studies, two were conducted during FT trainings in the United States, one in Australia, and one in Uganda.

Methods

The studies involve pre-, post-, and follow-up repeated-measures design to determine the effectiveness of a 15-min FT intervention. A total of 654 subjects were asked to think of a disturbing memory and then participate in a structured experience of an FT. The purpose of this investigation was to determine whether a brief application of an FT would be safe and effective in significantly reducing their disturbance. In each study, subjects rated their disturbing memories on a 0-to-10 scale, with zero representing no disturbance at all and 10 representing the worst they could imagine. Then, they took part in a 15-min group practicum where they were guided in a self-administering FT with no individual supervision or support.

Results

In all four studies, the mean reduction in disturbance exceeded two-thirds, the results were significant (p < 0.001), and the effect size was very large. Of the 813 sessions (654 subjects) represented in these studies, only two subjects reported slight increases in disturbances, and both of these subjects reported reductions in disturbance in their second FT experiences 2 h later. At a 4-week follow-up, mean disturbance levels in all four studies indicated maintenance of benefit or slightly further reduction of mean disturbance levels. An 18-month follow-up study with a subgroup of subjects who initially reported a high level of memory-related distress found similar maintenance of gains as well as symptom reduction.

Conclusion

These findings provide preliminary evidence of acceptability, safety, and efficacy of FT; therefore, further study is warranted.

Feasibility of mass cytometry proteomic characterisation of circulating tumour cells in head and neck squamous cell carcinoma for deep phenotyping

BACKGROUND

Circulating tumour cells (CTCs) are a potential cancer biomarker, but current methods of CTC analysis at single-cell resolution are limited. Here, we describe high-dimensional single-cell mass cytometry proteomic analysis of CTCs in HNSCC.

METHODS

Parsortix microfluidic-enriched CTCs from 14 treatment-naïve HNSCC patients were analysed by mass cytometry analysis using 41 antibodies. Immune cell lineage, epithelial-mesenchymal transition (EMT), stemness, proliferation and immune checkpoint expression was assessed alongside phosphorylation status of multiple signalling proteins. Patient-matched tumour gene expression and CTC EMT profiles were compared. Standard bulk CTC RNAseq was performed as a baseline comparator to assess mass cytometry data.

RESULTS

CTCs were detected in 13/14 patients with CTC counts of 2-24 CTCs/ml blood. Unsupervised clustering separated CTCs into epithelial, early EMT and advanced EMT groups that differed in signalling pathway activation state. Patient-specific CTC cluster patterns separated into immune checkpoint low and high groups. Patient tumour and CTC EMT profiles differed. Mass cytometry outperformed bulk RNAseq to detect CTCs and characterise cell phenotype.

DISCUSSION

We demonstrate mass cytometry allows high-plex proteomic characterisation of CTCs at single-cell resolution and identify common CTC sub-groups with potential for novel biomarker development and immune checkpoint inhibitor treatment stratification.

Design and Implementation of a National SARS-CoV-2 Monitoring Program in England: REACT-1 Study

Data System. The REal-time Assessment of Community Transmission-1 (REACT-1) Study was funded by the Department of Health and Social Care in England to provide reliable and timely estimates of prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection over time, by person and place. Data Collection/Processing. The study team (researchers from Imperial College London and its logistics partner Ipsos) wrote to named individuals aged 5 years and older in random cross-sections of the population of England, using the National Health Service list of patients registered with a general practitioner (near-universal coverage) as a sampling frame. We collected data over 2 to 3 weeks approximately every month across 19 rounds of data collection from May 1, 2020, to March 31, 2022. Data Analysis/Dissemination. We have disseminated the data and study materials widely via the study Web site, preprints, publications in peer-reviewed journals, and the media. We make available data tabulations, suitably anonymized to protect participant confidentiality, on request to the study's data access committee. Public Health Implications. The study provided inter alia real-time data on SARS-CoV-2 prevalence over time, by area, and by sociodemographic variables; estimates of vaccine effectiveness; and symptom profiles, and detected emergence of new variants based on viral genome sequencing. (Am J Public Health. 2023;113(5):545-554. https://doi.org/10.2105/AJPH.2023.307230).

Preferential uptake of SARS-CoV-2 by pericytes potentiates vascular damage and permeability in an organoid model of the microvasculature

AIMS

Thrombotic complications and vasculopathy have been extensively associated with severe COVID-19 infection; however, the mechanisms inducing endotheliitis and the disruption of endothelial integrity in the microcirculation are poorly understood. We hypothesized that within the vessel wall, pericytes preferentially take up viral particles and mediate the subsequent loss of vascular integrity.

METHODS AND RESULTS

Immunofluorescence of post-mortem patient sections was used to assess pathophysiological aspects of COVID-19 infection. The effects of COVID-19 on the microvasculature were assessed using a vascular organoid model exposed to live viral particles or recombinant viral antigens. We find increased expression of the viral entry receptor angiotensin-converting enzyme 2 on pericytes when compared to vascular endothelium and a reduction in the expression of the junctional protein CD144, as well as increased cell death, upon treatment with both live virus and/or viral antigens. We observe a dysregulation of genes implicated in vascular permeability, including Notch receptor 3, angiopoietin-2, and TEK. Activation of vascular organoids with interleukin-1β did not have an additive effect on vascular permeability. Spike antigen was detected in some patients' lung pericytes, which was associated with a decrease in CD144 expression and increased platelet recruitment and von Willebrand factor (VWF) deposition in the capillaries of these patients, with thrombi in large vessels rich in VWF and fibrin.

CONCLUSION

Together, our data indicate that direct viral exposure to the microvasculature modelled by organoid infection and viral antigen treatment results in pericyte infection, detachment, damage, and cell death, disrupting pericyte-endothelial cell crosstalk and increasing microvascular endothelial permeability, which can promote thrombotic and bleeding complications in the microcirculation.

Human T Lymphotropic Virus 1-Associated Myelopathy: Overview of Human T Cell Lymphotropic Virus-1/2 Tests and Potential Biomarkers

Human T cell lymphotropic virus (HTLV)-1-associated myelopathy is a chronic, disabling inflammatory disorder of the spinal cord caused by HTLV-1 infection. The diagnosis of HTLV-1-associated myelopathy (HAM) is based on clinical and laboratorial findings. The disease is characterized by the presence of spastic paraparesis associated with detection of anti-HTLV-1 antibodies or HTLV-1 genomes in blood and cerebrospinal fluid (CSF). New inflammatory markers have been proposed for the diagnosis and assessment of the prognosis of HAM. We reviewed the laboratory diagnostic and potential surrogate markers for HAM. The serological screening tests for detection of anti-HTLV-1/2 antibodies are highly sensitive and specific, but confirmation and typing of HTLV-1 or HTLV-2 infection by other serological or molecular methods are essential. Detection of intrathecal anti-HTLV-1 antibodies and quantification of the HTLV-1 provirus in CSF provide additional evidence for diagnosis especially in atypical cases or where alternative causes of neuroinflammation cannot be excluded. The CXC motif chemokine ligand 10 and neopterin in serum and CSF are now emerging as inflammatory markers with prognostic value and for HAM monitoring and management. In addition, measures of neurodegeneration, such as neurofilament light chain in the CSF and blood, may also contribute to the HAM prognosis. This review is useful for clinicians and researchers evaluating potential benefits and limitations of each biomarker in clinical practice. The advent of new markers makes it necessary to update the criteria for the best evidence-based approach and for worldwide consensus regarding the use of diagnostic and surrogate markers for HAM.

Characterizing the epithelial-mesenchymal transition status of circulating tumor cells in head and neck squamous cell carcinoma

BACKGROUND

Circulating tumor cells (CTCs), in particular those undergoing an epithelial-mesenchymal transition (EMT), are a promising source of biomarkers in head and neck squamous cell carcinoma (HNSCC). Our aim was to validate a protocol using microfluidic enrichment (Parsortix platform) with flow-cytometry CTC characterization.

METHOD

Blood samples from 20 treatment naïve HNSCC patients underwent Parsortix enrichment and flow cytometry analysis to quantify CTCs and identify epithelial or EMT subgroups-correlated to clinical outcomes and EMT gene-expression in tumor tissue.

RESULTS

CTCs were detected in 65% of patients (mean count 4 CTCs/ml). CTCs correlated with advanced disease (p = 0.0121), but not T or N classification. Epithelial or EMT CTCs did not correlate with progression-free or overall survival. Tumor mesenchymal gene-expression did not correlate with CTC EMT expression (p = 0.347).

DISCUSSION

Microfluidic enrichment and flow cytometry successfully characterizes EMT CTCs in HNSCC. The lack of association between tumor and CTC EMT profile suggests CTCs may undergo an adaptive EMT in response to stimuli within the circulation.

Determinants of neointimal strut coverage in bio-degradable polymer coated ultrathin strut stent

Introduction

Incomplete strut coverage (ISC) is the most important morphometric determinant of stent thrombosis. Determinants of ISC have been studied in thick and thin strut stents.

Purpose

To identify morphometric factors causing ISC in the biodegradable polymer-coated ultra-thin strut drug eluting stent (BP-UTS-DES) that are designed to encourage better strut coverage.

Methods

Patients undergoing implantation of a 65μm BP-UTS-DES had opportunistic OCT during staged PCI to assess strut coverage at 90 days. Images were analysed offline by experienced operators blinded to patient and procedural data. Neointimal thickness (NIT, μm) was measured as the minimum endoluminal distant between the strut and lumen border. All malapposed struts were considered uncovered. ISC was defined as &lt;100% covered struts in a frame. Stepwise logistic regression using multiple morphometric variables was used to identify independent determinants of ISC including markers of circumferential distribution of neointimal growth (CVS,NUS,RUS), symmetry of stent expansion (SEI, AVS, MAS) in each cross section and the geographical location of the frame along the axis of the stent.

Results

We analysed 11652 frames of 65 stents (1976 mm) in 46 arteries of 40 patients. All stents were post dilated. 95.6% arteries had &gt;20mm stents, 39.1% were overlapped and 15.2% were chronic total occlusions. Malapposition was seen in 2.6% of all struts and 39.2% of uncovered struts. The proportion of covered struts decreased as indices of circumferential uniformity of distribution of neointimal hyperplasia increased (CVS: r=0.37, p&lt;0.001; RUS: r=0.36, p&lt;0.001; NUS: r=0.52, p&lt;0.001). As uniformity of stent expansion improved (SEI increased) strut coverage and circumferential uniformity of neointimal hyperplasia increased (CVS, NUS and RUS decreased) suggesting that distribution of neointimal growth becomes homogeneous as uniformity of stent expansion improves (Fig. 1). Determinants ISC is shown in Table 1.

Conclusion

SEI but not AVS or MAS determines ISC. Compared to the distal third of the stent frames in the middle third had lower and the proximal third had high risk of ISC.

Funding Acknowledgement

Type of funding sources: None.

Omicron SARS-CoV-2 epidemic in England during February 2022: A series of cross-sectional community surveys

Background

The Omicron wave of COVID-19 in England peaked in January 2022 resulting from the rapid transmission of the Omicron BA.1 variant. We investigate the spread and dynamics of the SARS-CoV-2 epidemic in the population of England during February 2022, by region, age and main SARS-CoV-2 sub-lineage.

Methods

In the REal-time Assessment of Community Transmission-1 (REACT-1) study we obtained data from a random sample of 94,950 participants with valid throat and nose swab results by RT-PCR during round 18 (8 February to 1 March 2022).

Findings

We estimated a weighted mean SARS-CoV-2 prevalence of 2.88% (95% credible interval [CrI] 2.76-3.00), with a within-round effective reproduction number (R) overall of 0.94 (0·91-0.96). While within-round weighted prevalence fell among children (aged 5 to 17 years) and adults aged 18 to 54 years, we observed a level or increasing weighted prevalence among those aged 55 years and older with an R of 1.04 (1.00-1.09). Among 1,616 positive samples with sublineages determined, one (0.1% [0.0-0.3]) corresponded to XE BA.1/BA.2 recombinant and the remainder were Omicron: N=1047, 64.8% (62.4-67.2) were BA.1; N=568, 35.2% (32.8-37.6) were BA.2. We estimated an R additive advantage for BA.2 (vs BA.1) of 0.38 (0.34-0.41). The highest proportion of BA.2 among positives was found in London.

Interpretation

In February 2022, infection prevalence in England remained high with level or increasing rates of infection in older people and an uptick in hospitalisations. Ongoing surveillance of both survey and hospitalisations data is required.

Funding

Department of Health and Social Care, England.

Incisional hernia following colorectal cancer surgery according to suture technique: Hughes Abdominal Repair Randomized Trial (HART)

BACKGROUND

Incisional hernias cause morbidity and may require further surgery. HART (Hughes Abdominal Repair Trial) assessed the effect of an alternative suture method on the incidence of incisional hernia following colorectal cancer surgery.

METHODS

A pragmatic multicentre single-blind RCT allocated patients undergoing midline incision for colorectal cancer to either Hughes closure (double far-near-near-far sutures of 1 nylon suture at 2-cm intervals along the fascia combined with conventional mass closure) or the surgeon's standard closure. The primary outcome was the incidence of incisional hernia at 1 year assessed by clinical examination. An intention-to-treat analysis was performed.

RESULTS

Between August 2014 and February 2018, 802 patients were randomized to either Hughes closure (401) or the standard mass closure group (401). At 1 year after surgery, 672 patients (83.7 per cent) were included in the primary outcome analysis; 50 of 339 patients (14.8 per cent) in the Hughes group and 57 of 333 (17.1 per cent) in the standard closure group had incisional hernia (OR 0.84, 95 per cent c.i. 0.55 to 1.27; P = 0.402). At 2 years, 78 patients (28.7 per cent) in the Hughes repair group and 84 (31.8 per cent) in the standard closure group had incisional hernia (OR 0.86, 0.59 to 1.25; P = 0.429). Adverse events were similar in the two groups, apart from the rate of surgical-site infection, which was higher in the Hughes group (13.2 versus 7.7 per cent; OR 1.82, 1.14 to 2.91; P = 0.011).

CONCLUSION

The incidence of incisional hernia after colorectal cancer surgery is high. There was no statistical difference in incidence between Hughes closure and mass closure at 1 or 2 years.

REGISTRATION NUMBER

ISRCTN25616490 (http://www.controlled-trials.com).

Dynamics of competing SARS-CoV-2 variants during the Omicron epidemic in England

The SARS-CoV-2 pandemic has been characterised by the regular emergence of genomic variants. With natural and vaccine-induced population immunity at high levels, evolutionary pressure favours variants better able to evade SARS-CoV-2 neutralising antibodies. The Omicron variant (first detected in November 2021) exhibited a high degree of immune evasion, leading to increased infection rates worldwide. However, estimates of the magnitude of this Omicron wave have often relied on routine testing data, which are prone to several biases. Using data from the REal-time Assessment of Community Transmission-1 (REACT-1) study, a series of cross-sectional surveys assessing prevalence of SARS-CoV-2 infection in England, we estimated the dynamics of England's Omicron wave (from 9 September 2021 to 1 March 2022). We estimate an initial peak in national Omicron prevalence of 6.89% (5.34%, 10.61%) during January 2022, followed by a resurgence in SARS-CoV-2 infections as the more transmissible Omicron sub-lineage, BA.2 replaced BA.1 and BA.1.1. Assuming the emergence of further distinct variants, intermittent epidemics of similar magnitudes may become the 'new normal'.

SARS-CoV-2 lineage dynamics in England from September to November 2021: high diversity of Delta sub-lineages and increased transmissibility of AY.4.2

BACKGROUND

Since the emergence of SARS-CoV-2, evolutionary pressure has driven large increases in the transmissibility of the virus. However, with increasing levels of immunity through vaccination and natural infection the evolutionary pressure will switch towards immune escape. Genomic surveillance in regions of high immunity is crucial in detecting emerging variants that can more successfully navigate the immune landscape.

METHODS

We present phylogenetic relationships and lineage dynamics within England (a country with high levels of immunity), as inferred from a random community sample of individuals who provided a self-administered throat and nose swab for rt-PCR testing as part of the REal-time Assessment of Community Transmission-1 (REACT-1) study. During round 14 (9 September-27 September 2021) and 15 (19 October-5 November 2021) lineages were determined for 1322 positive individuals, with 27.1% of those which reported their symptom status reporting no symptoms in the previous month.

RESULTS

We identified 44 unique lineages, all of which were Delta or Delta sub-lineages, and found a reduction in their mutation rate over the study period. The proportion of the Delta sub-lineage AY.4.2 was increasing, with a reproduction number 15% (95% CI 8-23%) greater than the most prevalent lineage, AY.4. Further, AY.4.2 was less associated with the most predictive COVID-19 symptoms (p = 0.029) and had a reduced mutation rate (p = 0.050). Both AY.4.2 and AY.4 were found to be geographically clustered in September but this was no longer the case by late October/early November, with only the lineage AY.6 exhibiting clustering towards the South of England.

CONCLUSIONS

As SARS-CoV-2 moves towards endemicity and new variants emerge, genomic data obtained from random community samples can augment routine surveillance data without the potential biases introduced due to higher sampling rates of symptomatic individuals.

Broadening symptom criteria improves early case identification in SARS-CoV-2 contacts

BACKGROUND

The success of case isolation and contact tracing for the control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission depends on the accuracy and speed of case identification. We assessed whether inclusion of additional symptoms alongside three canonical symptoms (CS), i.e. fever, cough and loss or change in smell or taste, could improve case definitions and accelerate case identification in SARS-CoV-2 contacts.

METHODS

Two prospective longitudinal London (UK)-based cohorts of community SARS-CoV-2 contacts, recruited within 5 days of exposure, provided independent training and test datasets. Infected and uninfected contacts completed daily symptom diaries from the earliest possible time-points. Diagnostic information gained by adding symptoms to the CS was quantified using likelihood ratios and area under the receiver operating characteristic curve. Improvements in sensitivity and time to detection were compared with penalties in terms of specificity and number needed to test.

RESULTS

Of 529 contacts within two cohorts, 164 (31%) developed PCR-confirmed infection and 365 (69%) remained uninfected. In the training dataset (n=168), 29% of infected contacts did not report the CS. Four symptoms (sore throat, muscle aches, headache and appetite loss) were identified as early-predictors (EP) which added diagnostic value to the CS. The broadened symptom criterion "≥1 of the CS, or ≥2 of the EP" identified PCR-positive contacts in the test dataset on average 2 days earlier after exposure (p=0.07) than "≥1 of the CS", with only modest reduction in specificity (5.7%).

CONCLUSIONS

Broadening symptom criteria to include individuals with at least two of muscle aches, headache, appetite loss and sore throat identifies more infections and reduces time to detection, providing greater opportunities to prevent SARS-CoV-2 transmission.

Twin peaks: The Omicron SARS-CoV-2 BA.1 and BA.2 epidemics in England

Rapid transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has led to record-breaking incidence rates around the world. The Real-time Assessment of Community Transmission-1 (REACT-1) study has tracked SARS-CoV-2 infection in England using reverse transcription polymerase chain reaction (RT-PCR) results from self-administered throat and nose swabs from randomly selected participants aged 5 years and older approximately monthly from May 2020 to March 2022. Weighted prevalence in March 2022 was the highest recorded in REACT-1 at 6.37% (N = 109,181), with the Omicron BA.2 variant largely replacing the BA.1 variant. Prevalence was increasing overall, with the greatest increase in those aged 65 to 74 years and 75 years and older. This was associated with increased hospitalizations and deaths, but at much lower levels than in previous waves against a backdrop of high levels of vaccination.

Breakthrough SARS-CoV-2 infections in double and triple vaccinated adults and single dose vaccine effectiveness among children in Autumn 2021 in England: REACT-1 study

Background

Prevalence of SARS-CoV-2 infection with Delta variant was increasing in England in late summer 2021 among children aged 5 to 17 years, and adults who had received two vaccine doses. In September 2021, a third (booster) dose was offered to vaccinated adults aged 50 years and over, vulnerable adults and healthcare/care-home workers, and a single vaccine dose already offered to 16 and 17 year-olds was extended to children aged 12 to 15 years.

Methods

SARS-CoV-2 community prevalence in England was available from self-administered throat and nose swabs using reverse transcriptase polymerase chain reaction (RT-PCR) in round 13 (24 June to 12 July 2021, N = 98,233), round 14 (9 to 27 September 2021, N = 100,527) and round 15 (19 October to 5 November 2021, N = 100,112) from the REACT-1 study randomised community surveys. Linking to National Health Service (NHS) vaccination data for consenting participants, we estimated vaccine effectiveness in children aged 12 to 17 years and compared swab-positivity rates in adults who received a third dose with those who received two doses.

Findings

Weighted SARS-CoV-2 prevalence was 1.57% (1.48%, 1.66%) in round 15 compared with 0.83% (0.76%, 0.89%) in round 14, and the previously observed link between infections and hospitalisations and deaths had weakened. Vaccine effectiveness against infection in children aged 12 to 17 years was estimated (round 15) at 64.0% (50.9%, 70.6%) and 67.7% (53.8%, 77.5%) for symptomatic infections. Adults who received a third vaccine dose were less likely to test positive compared to those who received two doses, with adjusted OR of 0.36 (0.25, 0.53).

Interpretation

Vaccination of children aged 12 to 17 years and third (booster) doses in adults were effective at reducing infection risk. High rates of vaccination, including booster doses, are a key part of the strategy to reduce infection rates in the community.

Funding

Department of Health and Social Care, England.

Dominant Power and the Concept of Caste: Implications for Dentistry and Oral Health Inequality

This paper explores the issues of caste and casteism in the U.S. as described by Pulitzer Prize winning journalist Isabel Wilkerson in her 2020 book "Caste: The Origin of Our Discontents". Wilkerson argues that a caste system not only exists in the U.S. but operates as a hidden force affecting social inequality. The paper draws on Wilkerson's work to explore caste as an analytical concept. It begins by defining caste and casteism in contrast with racism, the eight pillars of a caste system, the consequences of casteism, and the psychological drivers of casteism. The paper then applies to concept of caste to understanding power, dentistry, and oral health inequality. The paper concludes by emphasizing that the concept of caste and its relationship to oral health inequality must be understood it if we want to create real social change.

Highly multiplexed, single-cell spatial phenotyping of Epstein-Barr virus infected tissues

The Epstein-Barr virus (EBV), a group 1 carcinogen, is a causative factor in nine different cancers that cause ~165,000 deaths globally each year. Almost all adults carry EBV asymptomatically; the virus persisting primarily in rare memory B cells for the lifetime of the host. However, in some infected individuals, for reasons that are unknown, EBV may contribute to the development of cancer. The immune microenvironment in which infected cells reside may influence or trigger cancer development, but we know very little about how this occurs. We have begun to address these critical questions by deploying a spatial biology assay for comprehensive study of the immune microenvironment of EBV-infected tissues. Using AKOYA’s immunofluorescence based Phenocycler assay, we developed an antibody panel that can detect 40 or more different biomarkers in situ at single cell resolution. The panel contains antibodies directed at EBV infected cells at various stages of viral infection, as well as biomarkers for different immune cell lineages, immune cell activation states and tissue structures. This design allows simultaneous identification of infected immune cells within their microenvironment, while, crucially, maintaining spatial relationships between them. We have now set out to produce unbiased and comprehensive spatial phenotypic maps of normal and EBV infected human FFPE tissues. Our data will provide an initial understanding of how the immune microenvironment of virus-infected cells influences tissue pathology and, ultimately, the development of cancer.

SARS-CoV-2 infection and vaccine effectiveness in England (REACT-1): a series of cross-sectional random community surveys

BACKGROUND

England has experienced a third wave of the COVID-19 epidemic since the end of May, 2021, coinciding with the rapid spread of the delta (B.1.617.2) variant, despite high levels of vaccination among adults. Vaccination rates (single dose) in England are lower among children aged 16-17 years and 12-15 years, whose vaccination in England commenced in August and September, 2021, respectively. We aimed to analyse the underlying dynamics driving patterns in SARS-CoV-2 prevalence during September, 2021, in England.

METHODS

The REal-time Assessment of Community Transmission-1 (REACT-1) study, which commenced data collection in May, 2020, involves a series of random cross-sectional surveys in the general population of England aged 5 years and older. Using RT-PCR swab positivity data from 100 527 participants with valid throat and nose swabs in round 14 of REACT-1 (Sept 9-27, 2021), we estimated community-based prevalence of SARS-CoV-2 and vaccine effectiveness against infection by combining round 14 data with data from round 13 (June 24 to July 12, 2021; n=172 862).

FINDINGS

During September, 2021, we estimated a mean RT-PCR positivity rate of 0·83% (95% CrI 0·76-0·89), with a reproduction number (R) overall of 1·03 (95% CrI 0·94-1·14). Among the 475 (62·2%) of 764 sequenced positive swabs, all were of the delta variant; 22 (4·63%; 95% CI 3·07-6·91) included the Tyr145His mutation in the spike protein associated with the AY.4 sublineage, and there was one Glu484Lys mutation. Age, region, key worker status, and household size jointly contributed to the risk of swab positivity. The highest weighted prevalence was observed among children aged 5-12 years, at 2·32% (95% CrI 1·96-2·73) and those aged 13-17 years, at 2·55% (2·11-3·08). The SARS-CoV-2 epidemic grew in those aged 5-11 years, with an R of 1·42 (95% CrI 1·18-1·68), but declined in those aged 18-54 years, with an R of 0·81 (0·68-0·97). At ages 18-64 years, the adjusted vaccine effectiveness against infection was 62·8% (95% CI 49·3-72·7) after two doses compared to unvaccinated people, for all vaccines combined, 44·8% (22·5-60·7) for the ChAdOx1 nCov-19 (Oxford-AstraZeneca) vaccine, and 71·3% (56·6-81·0) for the BNT162b2 (Pfizer-BioNTech) vaccine. In individuals aged 18 years and older, the weighted prevalence of swab positivity was 0·35% (95% CrI 0·31-0·40) if the second dose was administered up to 3 months before their swab but 0·55% (0·50-0·61) for those who received their second dose 3-6 months before their swab, compared to 1·76% (1·60-1·95) among unvaccinated individuals.

INTERPRETATION

In September, 2021, at the start of the autumn school term in England, infections were increasing exponentially in children aged 5-17 years, at a time when vaccination rates were low in this age group. In adults, compared to those who received their second dose less than 3 months ago, the higher prevalence of swab positivity at 3-6 months following two doses of the COVID-19 vaccine suggests an increased risk of breakthrough infections during this period. The vaccination programme needs to reach children as well as unvaccinated and partially vaccinated adults to reduce SARS-CoV-2 transmission and associated disruptions to work and education.

FUNDING

Department of Health and Social Care, England.

Rapid increase in Omicron infections in England during December 2021: REACT-1 study

The unprecedented rise in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections during December 2021 was concurrent with rapid spread of the Omicron variant in England and globally. We analyzed the prevalence of SARS-CoV-2 and its dynamics in England from the end of November to mid-December 2021 among almost 100,000 participants in the REACT-1 study. Prevalence was high with rapid growth nationally and particularly in London during December 2021, with an increasing proportion of infections due to Omicron. We observed large decreases in swab positivity among mostly vaccinated older children (12 to 17 years) relative to unvaccinated younger children (5 to 11 years), and in adults who received a third (booster) vaccine dose versus two doses. Our results reinforce the importance of vaccination and booster campaigns, although additional measures have been needed to control the rapid growth of the Omicron variant.

LRR-protein RNH1 dampens the inflammasome activation and is associated with COVID-19 severity

RNH1 prevents inflammation by inhibiting inflammasome activation through controlling caspase-1 protein levels. In COVID-19 patients, RNH1 expression levels were negatively associated with disease severity and inflammation, suggesting a role for RNH1 in SARS-CoV-2–mediated inflammation and pathology.

Inflammasomes are cytosolic innate immune sensors of pathogen infection and cellular damage that induce caspase-1–mediated inflammation upon activation. Although inflammation is protective, uncontrolled excessive inflammation can cause inflammatory diseases and can be detrimental, such as in coronavirus disease (COVID-19). However, the underlying mechanisms that control inflammasome activation are incompletely understood. Here we report that the leucine-rich repeat (LRR) protein ribonuclease inhibitor (RNH1), which shares homology with LRRs of NLRP (nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing) proteins, attenuates inflammasome activation. Deletion of RNH1 in macrophages increases interleukin (IL)-1β production and caspase-1 activation in response to inflammasome stimulation. Mechanistically, RNH1 decreases pro-IL-1β expression and induces proteasome-mediated caspase-1 degradation. Corroborating this, mouse models of monosodium urate (MSU)-induced peritonitis and lipopolysaccharide (LPS)-induced endotoxemia, which are dependent on caspase-1, respectively, show increased neutrophil infiltration and lethality in Rnh1^−/− mice compared with wild-type mice. Furthermore, RNH1 protein levels were negatively related with disease severity and inflammation in hospitalized COVID-19 patients. We propose that RNH1 is a new inflammasome regulator with relevance to COVID-19 severity.

Exponential growth, high prevalence of SARS-CoV-2, and vaccine effectiveness associated with the Delta variant

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections were rising during early summer 2021 in many countries as a result of the Delta variant. We assessed reverse transcription polymerase chain reaction swab positivity in the Real-time Assessment of Community Transmission–1 (REACT-1) study in England. During June and July 2021, we observed sustained exponential growth with an average doubling time of 25 days, driven by complete replacement of the Alpha variant by Delta and by high prevalence at younger, less-vaccinated ages. Prevalence among unvaccinated people [1.21% (95% credible interval 1.03%, 1.41%)] was three times that among double-vaccinated people [0.40% (95% credible interval 0.34%, 0.48%)]. However, after adjusting for age and other variables, vaccine effectiveness for double-vaccinated people was estimated at between ~50% and ~60% during this period in England. Increased social mixing in the presence of Delta had the potential to generate sustained growth in infections, even at high levels of vaccination.

Machine Learning-Based Predictive Modeling of Anxiety and Depressive Symptoms During 8 Months of the COVID-19 Global Pandemic: Repeated Cross-sectional Survey Study

BACKGROUND

The COVID-19 global pandemic has increased the burden of mental illness on Canadian adults. However, the complex combination of demographic, economic, and lifestyle factors and perceived health risks contributing to patterns of anxiety and depression has not been explored.

OBJECTIVE

The aim of this study is to harness flexible machine learning methods to identify constellations of factors related to symptoms of mental illness and to understand their changes over time during the COVID-19 pandemic.

METHODS

Cross-sectional samples of Canadian adults (aged ≥18 years) completed web-based surveys in 6 waves from May to December 2020 (N=6021), and quota sampling strategies were used to match the English-speaking Canadian population in age, gender, and region. The surveys measured anxiety and depression symptoms, sociodemographic characteristics, substance use, and perceived COVID-19 risks and worries. First, principal component analysis was used to condense highly comorbid anxiety and depression symptoms into a single data-driven measure of emotional distress. Second, eXtreme Gradient Boosting (XGBoost), a machine learning algorithm that can model nonlinear and interactive relationships, was used to regress this measure on all included explanatory variables. Variable importance and effects across time were explored using SHapley Additive exPlanations (SHAP).

RESULTS

Principal component analysis of responses to 9 anxiety and depression questions on an ordinal scale revealed a primary latent factor, termed "emotional distress," that explained 76% of the variation in all 9 measures. Our XGBoost model explained a substantial proportion of variance in emotional distress (r2=0.39). The 3 most important items predicting elevated emotional distress were increased worries about finances (SHAP=0.17), worries about getting COVID-19 (SHAP=0.17), and younger age (SHAP=0.13). Hopefulness was associated with emotional distress and moderated the impacts of several other factors. Predicted emotional distress exhibited a nonlinear pattern over time, with the highest predicted symptoms in May and November and the lowest in June.

CONCLUSIONS

Our results highlight factors that may exacerbate emotional distress during the current pandemic and possible future pandemics, including a role of hopefulness in moderating distressing effects of other factors. The pandemic disproportionately affected emotional distress among younger adults and those economically impacted.

DNA and modified vaccinia Ankara prime-boost vaccination generates strong CD8+ T cell responses against minor histocompatibility antigen HA-1

Allogeneic immune responses underlie the graft-versus-leukaemia effect of stem cell transplantation, but disease relapse occurs in many patients. Minor histocompatibility antigen (mHAg) peptides mediate alloreactive T cell responses and induce graft-versus-leukaemia responses when expressed on patient haematopoietic tissue. We vaccinated nine HA-1-negative donors against HA-1 with a 'prime-boost' protocol of either two or three DNA 'priming' vaccinations prior to 'boost' with modified vaccinia Ankara (MVA). HA-1-specific CD8+ T cell responses were observed in seven donors with magnitude up to 1·5% of total CD8+ T cell repertoire. HA-1-specific responses peaked two weeks post-MVA challenge and were measurable in most donors after 12 months. HA-1-specific T cells demonstrated strong cytotoxic activity and lysed target cells with endogenous HA-1 protein expression. The pattern of T cell receptor (TCR) usage by HA-1-specific T cells revealed strong conservation of T cell receptor beta variable 7-9 (TRBV7-9) usage between donors. These findings describe one of the strongest primary peptide-specific CD8+ T cell responses yet recorded to a DNA-MVA prime-boost regimen and this may reflect the strong immunogenicity of mHAg peptides. Prime-boost vaccination in donors or patients may prove of substantial benefit in boosting graft-versus-leukaemia responses.

Optimizing Pharmacology Studies in Pregnant and Lactating Women Using Lessons From HIV: A Consensus Statement

Information on the extent of drug exposure to mothers and infants during pregnancy and lactation normally becomes available years after regulatory approval of a drug. Clinicians face knowledge gaps on drug selection and dosing in pregnancy and infant exposure during breastfeeding. Physiological changes during pregnancy often result in lower drug exposures of antiretrovirals, and in some cases a risk of reduced virologic efficacy. The International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) network and the World Health Organization (WHO)-convened Pediatric Antiretrovirals Working Group collaboratively organized a workshop of key stakeholders in June 2019 to define key standards to generate pharmacology data for antiretrovirals to be used among pregnant and lactating women; review the antiretroviral product pipeline; describe key gaps for use in low-income and middle-income countries; and identify opportunities to undertake optimal studies allowing for rapid implementation in the clinical field. We discussed ethical and regulatory principles, systemic approaches to obtaining data for pregnancy pharmacokinetic/pharmacodynamic (PK/PD) studies, control groups, optimal sampling times during pregnancy, and pharmacokinetic parameters to be considered as primary end points in pregnancy PK/PD studies. For lactation studies, the type of milk to collect, ascertainment of maternal adherence, and optimal PK methods to estimate exposure were discussed. Participants strongly recommended completion of preclinical reproductive toxicology studies prior to phase III, to allow study protocols to include pregnant women or to allow women who become pregnant after enrolment to continue in the trial. The meeting concluded by developing an algorithm for design and interpretation of results and noted that recruitment of pregnant and lactating women into clinical trials is critical.

Hemispheric asymmetry in ocean change and the productivity of ecosystem sentinels

Climate change and other human activities are causing profound effects on marine ecosystem productivity. We show that the breeding success of seabirds is tracking hemispheric differences in ocean warming and human impacts, with the strongest effects on fish-eating, surface-foraging species in the north. Hemispheric asymmetry suggests the need for ocean management at hemispheric scales. For the north, tactical, climate-based recovery plans for forage fish resources are needed to recover seabird breeding productivity. In the south, lower-magnitude change in seabird productivity presents opportunities for strategic management approaches such as large marine protected areas to sustain food webs and maintain predator productivity. Global monitoring of seabird productivity enables the detection of ecosystem change in remote regions and contributes to our understanding of marine climate impacts on ecosystems.

Two alternative methods for the retrieval of somatic cell populations from the mouse ovary

Many modern techniques employed to uncover the molecular fundamentals underlying biological processes require dissociated cells as their starting point/substrate. Investigations into ovarian endocrinology or folliculogenesis, therefore, necessitate robust protocols for dissociating the ovary into its constituent cell populations. While in the mouse, methods to obtain individual, mature follicles are well-established, the separation and isolation of single cells of all types from early mouse follicles, including somatic cells, has been more challenging. Herein we present two methods for the isolation of somatic cells in the ovary. These methods are suitable for a range of applications relating to the study of folliculogenesis and mouse ovarian development. First, an enzymatic dissociation utilising collagenase and a temporary, primary cell culture step using neonatal mouse ovaries which yields large quantities of granulosa cells from primordial, activating, and primary follicles. Second, a rapid papain dissociation resulting in a high viability single cell suspension of ovarian somatic cells in less than an hour, which can be applied from embryonic to adult ovarian samples. Collectively these protocols can be applied to a broad array of investigations with unique advantages and benefits pertaining to both.

The Effect of Pregnancy on the Pharmacokinetics of Total and Unbound Dolutegravir and Its Main Metabolite in Women Living With Human Immunodeficiency Virus

BACKGROUND

Pharmacokinetic and efficacy data on dolutegravir in pregnant women living with human immunodeficiency virus (HIV) are still limited but needed to support its use as one of the preferred antiretroviral agents.

METHODS

Within the multicenter Pharmacokinetics of ANtiretroviral agents in HIV-infected pregNAnt women (PANNA) study, pregnant women living with HIV and using dolutegravir once daily (50 mg, with food) underwent 24-hour pharmacokinetic profiling in their third trimester and postpartum. Dolutegravir exposure in the third trimester was considered adequate if geometric mean unbound, pharmacologically active, minimal plasma concentrations (Cmin, unbound) and ≥90% of individual Cmin, unbound levels were >0.85 µg/L, the proposed 90% inhibitory concentration for unbound dolutegravir. Geometric mean ratios (GMRs) with 90% confidence intervals (CIs) for comparison of total and unbound pharmacokinetic parameters in the third trimester and postpartum were calculated, including the metabolic ratio for dolutegravir-glucuronide. Safety and virological data were collected.

RESULTS

Seventeen women (76% black) were enrolled (25 evaluable pharmacokinetic profiles; 15 in the third trimester, 10 in postpartum). In the third trimester, geometric mean (coefficient of variation, %) Cmin, unbound was 2.87 (87) µg/L and 93% of individual Cmin, unbound levels were >0.85 µg/L. The GMR (90% CI) in the third trimester vs postpartum was 0.86 (.68-1.10) for area under the curve (AUC0-24h), and for Cmax, 0.93 (.77-1.13). GMR (90% CI) for the trough concentrations was 0.71 (.49-1.02), based on total dolutegravir concentrations. Four serious adverse events were reported, unlikely related to dolutegravir. The HIV polymerase chain reaction test was negative in 14/17 infants (result unknown for 3 infants).

CONCLUSIONS

Pharmacokinetic changes for dolutegravir in late pregnancy are not clinically relevant and support the use of dolutegravir 50 mg once daily with food in pregnancy.

CLINICAL TRIALS REGISTRATION

NCT00825929.

Circulating Tumour Cell Expression of Immune Markers as Prognostic and Therapeutic Biomarkers in Head and Neck Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

Rates of loco-regional recurrence and distant metastasis remain high among head and neck squamous cell carcinoma (HNSCC) patients, despite advancing cancer treatment modalities and therapeutic agents. One area that has generated considerable interest is the immune landscape of the tumour, heralding a wave of immune checkpoint inhibitors with notable efficacy in recurrent/metastatic HNSCC patients. However, HNSCC remains poorly served by biomarkers that can direct treatment in a personalised fashion to target the tumour heterogeneity seen between patients. Detection and analysis of circulating tumour cells (CTCs) in HNSCC has provided a previously unseen view of the metastasis forming cells that are potentially contributing to poor clinical outcomes. In particular, identifying CTC expression of phenotypic and druggable protein markers has allowed CTC sub-populations to be defined that hold prognostic value or are potential therapeutic targets themselves. The aim of this systematic review was to examine the role of CTC immune-marker expression as prognostic/therapeutic biomarkers in HNSCC by evaluating progress to date and discussing areas for future research. Our results highlight how few studies have been able to demonstrate prognostic significance of immune-marker expression in CTCs. As expected, the immune checkpoint PD-L1 was the most widely investigated marker. However, no studies evaluated CTC target immune marker expression in immunotherapy cohorts. Despite these findings, the data presented demonstrate promise that CTCs may be a source of future biomarkers for immunotherapy and will provide valuable information regarding the potential immune evasion of these metastasis forming cells.

Incidence and treatment of positive pelvic sidewall lymph nodes in patients with rectal cancer

AIM

The involvement of pelvic sidewall (PSW) lymph nodes in rectal cancer is a marker of locally advanced disease and poor prognosis. Eastern countries generally advocate lateral lymph node dissection (LLND) over the Western approach of neoadjuvant chemoradiotherapy and more limited surgery. The aim of this study was to evaluate how these advanced cancers were treated in three UK Health Boards.

METHODOLOGY

This was a retrospective review of three colorectal multidisciplinary team meetings from 2008 to 2016. All patients with rectal cancer and suspicious PSW lymph nodes on pretreatment MRI were included.

RESULTS

There were 153 (6.2%) patients who met the inclusion criteria from a total of 2461 diagnosed rectal cancers. There was significant variability between the three centres with surgical intervention ranging from 59.2% to 84.4%, P = 0.015. There were 81 patients who had neoadjuvant chemoradiotherapy prior to surgery; of these 67 (82.7%) still had positive PSW nodes on the restaging MRI, but only 13 (19.4%) had LLND. There was no difference in local recurrence (15.3% vs 11.8%, P = 0.66), 5-year overall survival (69.2% vs 80.1%, P = 0.16) or 5-year disease-free survival (69.2% vs 79.4%, P = 0.72) between patients having LLND and those receiving standard neoadjuvant treatment followed by total mesorectal excision surgery.

CONCLUSIONS

This study has demonstrated that rectal cancer patients with PSW positive nodal disease have advanced disease, mostly of the lower rectum, and receive a highly heterogeneous spectrum of therapies, even within a relatively small geographical area. Greater accuracy in our preoperative staging is needed to select those patients who will benefit from LLND surgery.

Abstract 3274: A robust enhancement of cytokine production in a human chronic activation model of T cell exhaustion in vitro through blockade of PD-1/PDL-1 interactions using pembrolizumab or nivolumab; correlation with dissociated tumor immune cell responses

Prolonged exposure to antigens can lead to a state of reduced T cell responsiveness termed exhaustion. Restoring T cell functions from this state of reduced functionality by, for example, blockade of inhibitory immune checkpoints is now an established therapeutic modality with lasting impact on survival for some patients. Modelling human T cell exhaustion and its reversal in vitro can be challenging in medium or high-throughput assays. We have therefore sought to develop and characterize an in vitro model of T cell exhaustion using human T cells. Long-term (14-day) prolonged stimulation of human T cells in vitro led to both an up-regulation of established exhaustion markers PD-1, LAG-3 and TIM-3, and a lack of responsiveness to subsequent stimulation with human allogeneic monocyte-derived dendritic cells (DCs) as assessed by, for instance, IFNγ and TNFα production. Subsequent addition of blocking antibodies against PD-1 (pembrolizumab and nivolumab) led to a robust reversal of exhausted state by, for instance, restoration of cytokine secretion. The magnitude and nature of the response also correlated with the response of dissociated cells from lung and colon carcinomas. This response also showed greater sensitivity to PD-1 blockade compared to freshly isolated T cells or when using PBMCs stimulated with a pool of EBV peptides. By performing intracellular cytokine staining of human exhausted T cells stimulated with allogeneic dendritic cells, we further noted that PD-1 blockade using either pembrolizumab or nivolumab increased the percentage of cells producing IFNγ suggesting a greater responding pool of T cells. However, whilst the levels of the IFNγ in the supernatants of the exhausted T cell/allogeneic dendritic cell cultures was fully restored when compared to ‘fresh' T cell/allogeneic dendritic cell cultures, the percentage of IFNγ+ cells was not, nor was it fully restored by the inclusion of PMA/ionomycin. Taken together, this would suggest that PD-1 blockade induces responding cells to produce more IFNγ. We suggest that this chronic activation model of human T cell exhaustion with a robust assay window, and responsive to the clinically validated anti-PD-1 antibodies, nivolumab and pembrolizumab, may provide a platform for the discovery of new immuno-oncology therapeutics as well as the assessment of differences in mechanism of action between them.

Citation Format: Omar S. Qureshi, Alexander Roberts, Lindsay Bentley, Tina Tang, Fay Stewart, Graham Wallace, Alison Cooper, Aaron Scott, David Thickett, Babu Naidu, Thomas Pinkney, Graham Taylor, Kristian Brock, Louise Healy, Zania Stamataki, Catherine Brady, S J. Curnow, John Gordon, Nicholas M. Barnes. A robust enhancement of cytokine production in a human chronic activation model of T cell exhaustion in vitro through blockade of PD-1/PDL-1 interactions using pembrolizumab or nivolumab; correlation with dissociated tumor immune cell responses [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3274.

Understanding and optimising patient and public involvement in trial oversight: an ethnographic study of eight clinical trials

BACKGROUND

Trial oversight is important for trial governance and conduct. Patients and/or lay members of the public are increasingly included in trial oversight committees, influenced by international patient and public involvement (PPI) initiatives to improve the quality and relevance of research. However, there is a lack of guidance on how to undertake PPI in trial oversight and tokenistic PPI remains an issue. This paper explores how PPI functions in existing trial oversight committees and provides recommendations to optimise PPI in future trials. This was part of a larger study investigating the role and function of oversight committees in trials facing challenges.

METHODS

Using an ethnographic study design, we observed oversight meetings of eight UK trials and conducted semi-structured interviews with members of their trial steering committees (TSCs) and trial management groups (TMGs) including public contributors, trial sponsors and funders. Thematic analysis of data was undertaken, with findings integrated to provide a multi-perspective account of how PPI functions in trial oversight.

RESULTS

Eight TSC and six TMG meetings from eight trials were observed, and 66 semi-structured interviews conducted with 52 purposively sampled oversight group members, including three public contributors. PPI was reported as beneficial in trial oversight, with public members contributing a patient voice and fulfilling a patient advocacy role. However, public contributors were not always active at oversight meetings and were sometimes felt to have a tokenistic role, with trialists reporting a lack of understanding of how to undertake PPI in trial oversight. To optimise PPI in trial oversight, the following areas were highlighted: the importance of planning effective strategies to recruit public contributors; considering the level of oversight and stage(s) of trial to include PPI; support for public contributors by the trial team between and during oversight meetings.

CONCLUSIONS

We present evidence-based recommendations to inform future PPI in trial oversight. Consideration should be given at trial design stage on how to recruit and involve public contributors within trial oversight, as well as support and mentorship for both public contributors and trialists (in how to undertake PPI effectively). Findings from this study further strengthen the evidence base on facilitating meaningful PPI within clinical trials.

A new approach for investigating the response of lipid membranes to electrocompression by coupling droplet mechanics and membrane biophysics

A new method for quantifying lipid-lipid interactions within biomimetic membranes undergoing electrocompression is demonstrated by coupling droplet mechanics and membrane biophysics. The membrane properties are varied by altering the lipid packing through the introduction of cholesterol. Pendant drop tensiometry is used to measure the lipid monolayer tension at an oil-water interface. Next, two lipid-coated aqueous droplets are manipulated into contact to form a bilayer membrane at their adhered interface. The droplet geometries are captured from two angles to provide accurate measurements of both the membrane area and the contact angle between the adhered droplets. Combining the monolayer tension and contact angle measurements enables estimations of the membrane tension with respect to lipid composition. Then, the membrane is electromechanically compressed using a transmembrane voltage. Electrostatic pressure, membrane tension and the work necessary for bilayer thinning are tracked, and a model is proposed to capture the mechanics of membrane compression. The results highlight that a previously unaccounted for energetic term is produced during compression, potentially reflecting changes in the lateral membrane structure. This residual energy is eliminated in cases with cholesterol mole fractions of 0.2 and higher, suggesting that cholesterol diminishes these adjustments.

Sustainable bioenergy for climate mitigation: developing drought-tolerant trees and grasses

BACKGROUND AND AIMS

Bioenergy crops are central to climate mitigation strategies that utilize biogenic carbon, such as BECCS (bioenergy with carbon capture and storage), alongside the use of biomass for heat, power, liquid fuels and, in the future, biorefining to chemicals. Several promising lignocellulosic crops are emerging that have no food role - fast-growing trees and grasses - but are well suited as bioenergy feedstocks, including Populus, Salix, Arundo, Miscanthus, Panicum and Sorghum.

SCOPE

These promising crops remain largely undomesticated and, until recently, have had limited germplasm resources. In order to avoid competition with food crops for land and nature conservation, it is likely that future bioenergy crops will be grown on marginal land that is not needed for food production and is of poor quality and subject to drought stress. Thus, here we define an ideotype for drought tolerance that will enable biomass production to be maintained in the face of moderate drought stress. This includes traits that can readily be measured in wide populations of several hundred unique genotypes for genome-wide association studies, alongside traits that are informative but can only easily be assessed in limited numbers or training populations that may be more suitable for genomic selection. Phenotyping, not genotyping, is now the major bottleneck for progress, since in all lignocellulosic crops studied extensive use has been made of next-generation sequencing such that several thousand markers are now available and populations are emerging that will enable rapid progress for drought-tolerance breeding. The emergence of novel technologies for targeted genotyping by sequencing are particularly welcome. Genome editing has already been demonstrated for Populus and offers significant potential for rapid deployment of drought-tolerant crops through manipulation of ABA receptors, as demonstrated in Arabidopsis, with other gene targets yet to be tested.

CONCLUSIONS

Bioenergy is predicted to be the fastest-developing renewable energy over the coming decade and significant investment over the past decade has been made in developing genomic resources and in collecting wild germplasm from within the natural ranges of several tree and grass crops. Harnessing these resources for climate-resilient crops for the future remains a challenge but one that is likely to be successful.

High-Altitude Wild Species Solanum arcanum LA385-A Potential Source for Improvement of Plant Growth and Photosynthetic Performance at Suboptimal Temperatures

Plant growth, development, and yield of current tomato cultivars are directly affected by low temperatures. Although wild tomato species have been suggested as a potential source for low temperature tolerance, very little is known about their behavior during the reproductive phase. Here, we investigated the impact of suboptimal temperatures (SOT, 16/14°C), as compared to control temperatures (CT, 22/20°C), on plant growth, photosynthetic capacity, and carbohydrate metabolism. Under these conditions, two genotypes were analyzed: a Solanum lycopersicum cultivar Moneymaker and a high-altitude wild species Solanum arcanum LA385, from flowering onset until a later stage of fruit development. Total dry matter production in cv. Moneymaker was reduced up to 30% at SOT, whereas it was hardly affected in wild accession LA385. Specific leaf area, total leaf area, and number of fruits were also decreased at SOT in cv. Moneymaker. In contrast, wild accession LA385 showed an acclimation to SOT, in which Φ_PSII and net CO₂ assimilation rates were less affected; a similar specific leaf area; higher total leaf area; and higher number of fruits compared to those at CT. In addition, LA385 appeared to have a more distinct sucrose metabolism than cv. Moneymaker at both temperatures, in which it had higher contents of sucrose-6-phosphate, sucrose, and ratio of sucrose: starch in leaves and higher ratio of sucrose: hexose in fruits. Overall, our findings indicate that wild accession LA385 is able to acclimate well to SOT during the reproductive phase, whereas growth and development of cv. Moneymaker is reduced at SOT.

Deciphering Melatonin-Stabilized Phase Separation in Phospholipid Bilayers

Lipid bilayers are fundamental building blocks of cell membranes, which contain the machinery needed to perform a range of biological functions, including cell-cell recognition, signal transduction, receptor trafficking, viral budding, and cell fusion. Importantly, many of these functions are thought to take place in the laterally phase-separated regions of the membrane, commonly known as lipid rafts. Here, we provide experimental evidence for the "stabilizing" effect of melatonin, a naturally occurring hormone produced by the brain's pineal gland, on phase-separated model membranes mimicking the outer leaflet of plasma membranes. Specifically, we show that melatonin stabilizes the liquid-ordered/liquid-disordered phase coexistence over an extended range of temperatures. The melatonin-mediated stabilization effect is observed in both nanometer- and micrometer-sized liposomes using small angle neutron scattering (SANS), confocal fluorescence microscopy, and differential scanning calorimetry. To experimentally detect nanoscopic domains in 50 nm diameter phospholipid vesicles, we developed a model using the Landau-Brazovskii approach that may serve as a platform for detecting the existence of nanoscopic lateral heterogeneities in soft matter and biological materials with spherical and planar geometries.

Peptide-Induced Lipid Flip-Flop in Asymmetric Liposomes Measured by Small Angle Neutron Scattering

Despite the prevalence of lipid transbilayer asymmetry in natural plasma membranes, most biomimetic model membranes studied are symmetric. Recent advances have helped to overcome the difficulties in preparing asymmetric liposomes in vitro, allowing for the examination of a larger set of relevant biophysical questions. Here, we investigate the stability of asymmetric bilayers by measuring lipid flip-flop with time-resolved small-angle neutron scattering (SANS). Asymmetric large unilamellar vesicles with inner bilayer leaflets containing predominantly 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and outer leaflets composed mainly of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) displayed slow spontaneous flip-flop at 37 ^◦C (half-time, t_1/2 = 140 h). However, inclusion of peptides, namely, gramicidin, alamethicin, melittin, or pHLIP (i.e., pH-low insertion peptide), accelerated lipid flip-flop. For three of these peptides (i.e., pHLIP, alamethicin, and melittin), each of which was added externally to preformed asymmetric vesicles, we observed a completely scrambled bilayer in less than 2 h. Gramicidin, on the other hand, was preincorporated during the formation of the asymmetric liposomes and showed a time resolvable 8-fold increase in the rate of lipid asymmetry loss. These results point to a membrane surface-related (e.g., adsorption/insertion) event as the primary driver of lipid scrambling in the asymmetric model membranes of this study. We discuss the implications of membrane peptide binding, conformation, and insertion on lipid asymmetry.

Circulating Tumour Cell Biomarkers in Head and Neck Cancer: Current Progress and Future Prospects

Head and neck cancer (HNC) continues to carry a significant burden of disease both for patients and health services. Facilitating biomarker-led treatment decisions is critical to improve outcomes in this group and deliver therapy tailored to the individual tumour biological profile. One solution to develop such biomarkers is a liquid biopsy analysing circulating tumour cells (CTCs)-providing a non-invasive and dynamic assessment of tumour specific alterations in 'real-time'. A major obstacle to implementing such a test is the standardisation of CTC isolation methods and subsequent down-stream analysis. Several options are available, with a recent shift in vogue from positive-selection marker-dependent isolation systems to marker-independent negative-selection techniques. HNC single-CTC characterisation, including single-cell sequencing, to identify actionable mutations and gene-expression signatures has the potential to both guide the understanding of patient tumour heterogeneity and support the adoption of personalised medicine strategies. Microfluidic approaches for isolating CTCs and cell clusters are emerging as novel technologies which can be incorporated with computational platforms to complement current diagnostic and prognostic strategies. We review the current literature to assess progress regarding CTC biomarkers in HNC and potential avenues for future translational research and clinical implementation.

Loss of carotenoids from membranes of Pantoea sp. YR343 results in altered lipid composition and changes in membrane biophysical properties

Bacterial membranes are complex mixtures of lipids and proteins, the combination of which confers biophysical properties that allows cells to respond to environmental conditions. Carotenoids are sterol analogs that are important for regulating membrane dynamics. The membrane of Pantoea sp. YR343 is characterized by the presence of the carotenoid zeaxanthin, and a carotenoid-deficient mutant, ΔcrtB, displays defects in root colonization, reduced secretion of indole-3-acetic acid, and defects in biofilm formation. Here we demonstrate that the loss of carotenoids results in changes to the membrane lipid composition in Pantoea sp. YR343, including increased amounts of unsaturated fatty acids in the ΔcrtB mutant membranes. These mutant cells displayed less fluid membranes in comparison to wild type cells as measured by fluorescence anisotropy of whole cells. Studies with artificial systems, however, have shown that carotenoids impart membrane rigidifying properties. Thus, we examined membrane fluidity using spheroplasts and vesicles composed of lipids extracted from either wild type or mutant cells. Interestingly, with the removal of the cell wall and membrane proteins, ΔcrtB vesicles were more fluid than vesicles made from lipids extracted from wild type cells. In addition, carotenoids appeared to stabilize membrane fluidity during rapidly changing temperatures. Taken together, these results suggest that Pantoea sp. YR343 compensates for the loss of carotenoids by changing lipid composition, which together with membrane proteins, results in reduced membrane fluidity. These changes may influence the abundance or function of membrane proteins that are responsible for the physiological changes observed in the ΔcrtB mutant cells.

Regulation of S1PR2 by the EBV oncogene LMP1 in aggressive ABC-subtype diffuse large B-cell lymphoma

The Epstein-Barr virus (EBV) is found almost exclusively in the activated B-cell (ABC) subtype of diffuse large B-cell lymphoma (DLBCL), yet its contribution to this tumour remains poorly understood. We have focused on the EBV-encoded latent membrane protein-1 (LMP1), a constitutively activated CD40 homologue expressed in almost all EBV-positive DLBCLs and which can disrupt germinal centre (GC) formation and drive lymphomagenesis in mice. Comparison of the transcriptional changes that follow LMP1 expression with those that follow transient CD40 signalling in human GC B cells enabled us to define pathogenic targets of LMP1 aberrantly expressed in ABC-DLBCL. These included the down-regulation of S1PR2, a sphingosine-1-phosphate (S1P) receptor that is transcriptionally down-regulated in ABC-DLBCL, and when genetically ablated leads to DLBCL in mice. Consistent with this, we found that LMP1-expressing primary ABC-DLBCLs were significantly more likely to lack S1PR2 expression than were LMP1-negative tumours. Furthermore, we showed that the down-regulation of S1PR2 by LMP1 drives a signalling loop leading to constitutive activation of the phosphatidylinositol-3-kinase (PI3-K) pathway. Finally, core LMP1-PI3-K targets were enriched for lymphoma-related transcription factors and genes associated with shorter overall survival in patients with ABC-DLBCL. Our data identify a novel function for LMP1 in aggressive DLBCL. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Hypothalamic mechanism of corticotropin-releasing factor's anorexigenic effect in Japanese quail (Coturnix japonica)

Central administration of corticotropin-releasing factor (CRF), a 41-amino acid peptide, is associated with anorexigenic effects across various species, with particularly potent reductions in food intake in rodents and chickens (Gallus gallus domesticus), a species for which the most is known. The purpose of the current study was to determine the hypothalamic mechanism of CRF-induced anorexigenic effects in 7 day-old Japanese quail (Coturnix japonica), a less-intensely-selected gallinaceous relative to the chicken that can provide more evolutionary perspective. After intracerebroventricular (ICV) injection of 2, 22, or 222 pmol of CRF, a dose-dependent decrease in food intake was observed that lasted for 3 and 24 h for the 22 and 222 pmol doses, respectively. The 2 pmol dose had no effect on food or water intake. The numbers of c-Fos immunoreactive cells were increased in the paraventricular nucleus (PVN) and lateral hypothalamic area (LHA) at 1 h post-injection in quail injected with 22 pmol of CRF. The hypothalamic mRNA abundance of proopiomelanocortin, melanocortin receptor subtype 4, CRF, and CRF receptor sub-type 2 was increased at 1 h in quail treated with 22 pmol of CRF. Behavior analyses demonstrated that CRF injection reduced feeding pecks and jumps and increased the time spent standing. In conclusion, results demonstrate that the anorexigenic effects of CRF in Japanese quail are likely influenced by the interaction between CRF and melanocortin systems and that injection of CRF results in species-specific behavioral changes.

Progress in ITER ECE Diagnostic Design and Integration

The ITER Electron Cyclotron Emission (ECE) diagnostic is progressing towards its Preliminary Design Review (PDR). In parallel, the diagnostic integration in the Equatorial Port is ongoing. Port Integration has to address the structural integrity to withstand various loads, maintenance and the safety aspects of ECE diagnostic. The ITER ECE system includes radial and oblique lines-of-sight. Recently, a successful peer-review of the in-port plug Hot Calibration Source has taken place and its performance and integration feasibility has been demonstrated. Four 45-meter long low-loss transmission lines are designed to transmit mm-wave power in the frequency range of 70- 1000 GHz in both X- and O-mode polarization from the port plug to the ECE instrumentation room in the diagnostic building. Prototype transmission lines are being tested [1]. A prototype polarizing Martin-Puplett type Fourier Transform Spectrometer (FTS) operating in the frequency range 70-1000 GHz, has a fast scanning mechanism and a cryo-cooled dual-channel THz detector system. Its performance has been tested as per ITER requirements. Assessment of the instrumentation and control requirements, functional and non-functional requirements, operation procedures, plant automation are ongoing for the PDR. The current status of the diagnostic, together with integration activities, is presented.