Single-cell transcriptomic atlas of lung microvascular regeneration after targeted endothelial cell ablation.

We sought to define the mechanism underlying lung microvascular regeneration in a model of severe acute lung injury (ALI) induced by selective lung endothelial cell ablation. Intratracheal instillation of DT in transgenic mice expressing human diphtheria toxin (DT) receptor targeted to ECs resulted in ablation of >70% of lung ECs, producing severe ALI with near complete resolution by 7 days. Using single-cell RNA sequencing, eight distinct endothelial clusters were resolved, including alveolar aerocytes (aCap) ECs expressing apelin at baseline and general capillary (gCap) ECs expressing the apelin receptor. At 3 days post-injury, a novel gCap EC population emerged characterized by de novo expression of apelin, together with the stem cell marker, protein C receptor. These stem-like cells transitioned at 5 days to proliferative endothelial progenitor-like cells, expressing apelin receptor together with the pro-proliferative transcription factor, Foxm1, and were responsible for the rapid replenishment of all depleted EC populations by 7 days post-injury. Treatment with an apelin receptor antagonist prevented ALI resolution and resulted in excessive mortality, consistent with a central role for apelin signaling in EC regeneration and microvascular repair. The lung has a remarkable capacity for microvasculature EC regeneration which is orchestrated by newly emergent apelin-expressing gCap endothelial stem-like cells that give rise to highly proliferative, apelin receptor-positive endothelial progenitors responsible for the regeneration of the lung microvasculature.

A propensity score matching analysis for CPAP versus conventional oxygen therapy as a ceiling of care in COVID-19-associated type 1 respiratory failure

Background Continuous positive airway pressure (CPAP) is increasingly used as a ward ceiling of care. Nevertheless, little is known about its effectiveness. Objective A retrospective study to explore whether CPAP therapy as a ceiling of care improves outcome in coronavirus disease 2019 (COVID-19)-infected patients with acute respiratory failure. Methods A retrospective cohort study was conducted on adult COVID-19-infected patients admitted to two UK hospitals from the March 1 to June 30, 2020. All patients experienced type 1 respiratory failure and were not suitable for intubation. They were divided into two groups: patients for CPAP versus conventional oxygen therapy (COT). Results A total of 39 patients received CPAP, whereas 247 received COT. CPAP group patients were more hypoxic (mean SpO2 86.5% vs. 91%, P=0.003), younger (mean±SD: 71.8±8.8 vs. 80.7±9.8 years, P<0.001), and less frail than the COT group [median (interquartile range) clinical frailty score 4 (3–5) vs. 6 (4–7), P<0.001]. Overall, 35 patients died in the CPAP group (89.7%) compared with 185 patients in the COT group (74.9%) (P=0.041). Propensity score matching of the two groups showed that CPAP was still associated with higher mortality (90.3 vs. 67.7%, P=0.029). Length of hospital stay was similar in both groups (mean±SD 9.2±7.3 vs. 9.7±8.6 days, P=0.719). Conclusion In COVID-19-infected patients presenting with type 1 respiratory failure and deemed not suitable for escalation to intubation, the use of CPAP therapy does not carry extra benefit than COT. In such patients, COT appears to be the appropriate measure. Further studies are required to corroborate these findings.

Social Distancing Crowd Segmentation, Estimation and Visualisation

This research shows a modern crowd counting solution which alters typical prediction solutions into a segmentation of individuals based on a distance threshold, allowing for better visualisation and results. The study proposes using YOLOv4-normal and YOLOv4-tiny models, which have shown great results throughout calibration with an MAE of 14 and 36 respectively. However it did present some issues of accuracy degradation when trained on head annotations at any level of crowd density. As for visualisation, perspective transformation was used which directly helped in providing the distance calculation that was absent from standard transformation. If any variants of YOLOv4 are to be used, the main argument is the choice between speed over accuracy while relying on native implementations. In the case of distance regulation, any transformation that maps itself onto the region of interest, such as perspective transformation should be used to precisely determine distances from a camera to the region of interest itself. © 2021 IEEE.

Poly(I:C) enhances mesenchymal stem cell control of myeloid cells from COVID-19 patients.

Mesenchymal stem cells (MSCs) are being studied for the treatment of COVID-19-associated critical illness, due to their immunomodulatory properties. Here, we hypothesized that viral mimic-priming improves MSCs' abilities to rebalance the dysregulated immune responses in COVID-19. Transcriptome analysis of poly(I:C)-primed MSCs (pIC-MSCs) showed upregulation of pathways in antiviral and immunomodulatory responses. Together with increased expression of antiviral proteins such as MX1, IFITM3, and OAS1, these changes translated to greater effector functions in regulating monocytes and granulocytes while further enhancing MSCs' ability to block SARS-CoV-2 pseudovirus entry into epithelial cells. Most importantly, the addition of pIC-MSCs to COVID-19 patient whole blood significantly reduced inflammatory neutrophils and increased M2 monocytes while enhancing their phagocytic effector function. We reveal for the first time that MSCs can be primed by Toll-like receptor 3 agonist to improve their ability to rebalance the dysregulated immune responses seen in severe SARS-CoV-2 infection.

Challenges in the implementation of COSA Teletrial model in the Monash-Gippsland Teletrial project

Background: The COSA Teletrial framework was piloted in 2017 and recently adopted as the national principles for teletrials (1). The Monash-Gippsland (MG) Teletrial project was initiated in 2019, funded by the Victorian Cancer Agency, aiming to increase clinical trials access for regional patients. The project was impacted by the COVID-19 pandemic lockdowns and recommenced in April 2021. Key learnings from the project are presented here. Aims: To report on the barriers and enablers found within the MG Teletrial project. Methods : A review of project meeting minutes was undertaken alongside informal discussions with participants and key stakeholders. Challenges affecting Latrobe Regional Hospital (LRH) in adopting open trials at Monash Health (MH) were itemised below. Results : Governance processes are lengthy and complex despite the adoption of COSA model by both health services with existing central ethics approval. Infrastructure and partnerships: Outsourcing of LRH pathology and radiology to private providers requires additional contracting and costs. Lack of cancer prescribing software at MH and common Electronic Medical Record pose difficulties with source documents management. The funding from collaborative partnerships allows LRH to successfully join the Regional Trials with critical research resources. Regular communications via teleconferencing has greatly facilitated progress. Staffing: The nature of appointments with fractional oncologist at LRH present challenges in clinical trials development. Access to the project funded full-timeMH Teletrial fellow working alongside the Trials Hub funded consultant and LRH study coordinator was essential. Logistics: Staff exchanges for training have been repeatedly thwarted by sudden lockdowns. Technical issues including a major malware attack on LRH email significantly impacted communications for months in 2019. Conclusions : The establishment of Teletrial at a greenfield site is complex and requires significant, longer term infrastructure support, including human and non-human resources.

Mesenchymal stromal cell extracellular vesicles as therapy for acute and chronic respiratory diseases: A meta-analysis.

Preclinical studies suggest mesenchymal stromal cell extracellular vesicles (MSC-EVs) reduce inflammation and improve organ function in lung diseases; however, an objective analysis of all available data is needed prior to translation. Using rigorous meta-research methods, we determined the effectiveness of MSC-EVs for preclinical respiratory diseases and identified experimental conditions that may further refine this therapy. A systematic search of MEDLINE/Embase identified 1167 records. After screening, 52 articles were included for data extraction and evaluated for risk of bias and quality of reporting in study design. A random effects meta-analysis was conducted for acute lung injury (ALI; N = 23), bronchopulmonary dysplasia (BPD; N = 8) and pulmonary arterial hypertension (PAH; N = 7). Subgroup analyses identified EV methods/characteristics that may be associated with improved efficacy. Data is presented as standardized mean differences (SMD) or risk ratios (RR) with 95% confidence intervals (CI). For ALI, MSC-EVs markedly reduced lung injury (SMD -4.33, CI -5.73 to -2.92), vascular permeability (SMD -2.43, CI -3.05 to -1.82), and mortality (RR 0.39, CI 0.22 to 0.68). Small EVs were more consistently effective than large EVs whereas no differences were observed between tissue sources, immunocompatibility or isolation techniques. For BPD, alveolarization was improved by MSC-EVs (SMD -1.45, CI -2.08 to -0.82) with small EVs more consistently beneficial then small/large EVs. In PAH, right ventricular systolic pressure (SMD -4.16, CI -5.68 to -2.64) and hypertrophy (SMD -2.80, CI -3.68 to -1.91) were significantly attenuated by EVs. In BPD and PAH, EVs isolated by ultracentrifugation demonstrated therapeutic benefit whereas tangential flow filtration (N = 2) displayed minimal efficacy. Lastly, risk of bias and quality of reporting for experimental design were consistently unclear across all studies. Our findings demonstrate clear potential of MSC-EVs to be developed as therapy for acute and chronic lung diseases. However, greater transparency in research design and direct comparisons of isolation technique and EV subtypes are needed to generate robust evidence to guide clinical translation. Protocol Registration: PROSPERO CRD42020145334.

The death of neoliberalism? UK responses to the pandemic

It is sometimes argued that unprecedented and drastic interventions to mitigate the economic and social effects of the pandemic must herald the diminution of neoliberal ideology in guiding UK government responses. However, by reference to government approaches to the previous crisis in 2008, and the recession that followed, that view is here considered to be simplistic, resting in part upon an over-narrow understanding of neoliberalism. Instead, it is argued that neoliberal ideology was maintained and further embedded in responding to the financial crisis and recession, especially apparent in the prolonged austerity regime that followed. How this ideology has remained influential in guiding government responses to the pandemic is next demonstrated, and some negative consequences highlighted for both public health and social welfare. Prospects for challenging the influence of neoliberalism are then considered. In some respects, the pandemic may have enhanced resistance to such challenges by, for instance, fragmenting the cohesion of workforces, but it has also generated countervailing forces. These include the emergence of mutual aid groups and social movements which could beneficially coalesce via a human rights framework in undermining the continuing dominance of neoliberal ideology and influence. © 2021 Informa UK Limited, trading as Taylor & Francis Group.

Nebulised heparin for patients with or at risk of acute respiratory distress syndrome: a multicentre, randomised, double-blind, placebo-controlled phase 3 trial.

BACKGROUND: Mechanical ventilation in intensive care for 48 h or longer is associated with the acute respiratory distress syndrome (ARDS), which might be present at the time ventilatory support is instituted or develop afterwards, predominantly during the first 5 days. Survivors of prolonged mechanical ventilation and ARDS are at risk of considerably impaired physical function that can persist for years. An early pathogenic mechanism of lung injury in mechanically ventilated, critically ill patients is inflammation-induced pulmonary fibrin deposition, leading to thrombosis of the microvasculature and hyaline membrane formation in the air sacs. The main aim of this study was to determine if nebulised heparin, which targets fibrin deposition, would limit lung injury and thereby accelerate recovery of physical function in patients with or at risk of ARDS. METHODS: The Can Heparin Administration Reduce Lung Injury (CHARLI) study was an investigator-initiated, multicentre, double-blind, randomised phase 3 trial across nine hospitals in Australia. Adult intensive care patients on invasive ventilation, with impaired oxygenation defined by a PaO2/FiO2 ratio of less than 300, and with the expectation of invasive ventilation beyond the next calendar day were recruited. Key exclusion criteria were heparin allergy, pulmonary bleeding, and platelet count less than 50 X 109/L. Patients were randomly assigned 1:1, with stratification by site and using blocks of variable size and random seed, via a web-based system, to either unfractionated heparin sodium 25 000 IU in 5 mL or identical placebo (sodium chloride 0·9% 5 mL), administered using a vibrating mesh membrane nebuliser every 6 h to day 10 while invasively ventilated. Patients, clinicians, and investigators were masked to treatment allocation. The primary outcome was the Short Form 36 Health Survey Physical Function Score (out of 100) of survivors at day 60. Prespecified secondary outcomes, which are exploratory, included development of ARDS to day 5 among at-risk patients, deterioration of the Murray Lung Injury Score (MLIS) to day 5, mortality at day 60, residence of survivors at day 60, and serious adverse events. Analyses followed the intention-to-treat principle. There was no imputation of missing data. The trial is registered with the Australian and New Zealand Clinical Trials Register, number ACTRN12612000418875 . FINDINGS: Between Sept 4, 2012, and Aug 23, 2018, 256 patients were randomised. Final follow-up was on Feb 25, 2019. We excluded three patients who revoked consent and one ineligible participant who received no intervention. Of 252 patients included in data analysis, the mean age was 58 years (SD 15), 157 (62%) were men, and 118 (47%) had ARDS. 128 (51%) patients were assigned to the heparin group and 124 (49%) to the placebo group, all of whom received their assigned intervention. Survivors in the heparin group (n=97) had similar SF-36 Physical Function Scores at day 60 compared to the placebo group (n=94; mean 53·6 [SD 31·6] vs 48·7 [35·7]; difference 4·9 [95% CI -4·8 to 14·5]; p=0·32). Compared with the placebo group, the heparin group had fewer cases of ARDS develop to day 5 among the at-risk patients (nine [15%] of 62 patients vs 21 [30%] of 71 patients; hazard ratio 0·46 [95% CI 0·22 to 0·98]; p=0·0431), less deterioration of the MLIS to day 5 (difference -0·14 [-0·26 to -0·02]; p=0·0215), similar day 60 mortality (23 [18%] of 127 patients vs 18 [15%] of 123 patients; odds ratio [OR] 1·29 [95% CI 0·66 to 2·53]; p=0·46), and more day 60 survivors at home (86 [87%] of 99 patients vs 73 [73%] of 100 patients; OR 2·45 [1·18 to 5·08]; p=0·0165). A similar number of serious adverse events occurred in each group (seven [5%] of 128 patients in the heparin group vs three [2%] of 124 patients in the placebo group; OR 2·33 [0·59 to 9·24]; p=0·23), which were a transient increase in airway pressure during nebulisation (n=3 in the heparin group), major non-pulmonary bleeding (n=2 in each group), haemoptysis (n=1 in the heparin group), tracheotomy site bleeding (n=1 in the heparin group), and hypoxaemia during nebulisation (n=1 in the placebo group). INTERPRETATION: In patients with or at risk of ARDS, nebulised heparin did not improve self-reported performance of daily physical activities, but was well tolerated and exploratory outcomes suggest less progression of lung injury and earlier return home. Further research is justified to establish if nebulised heparin accelerates recovery in those who have or are at risk of ARDS. FUNDING: Rowe Family Foundation, TR and RB Ditchfield Medical Research Endowment Fund, Patricia Madigan Charitable Trust, and The J and R McGauran Trust Fund.

CPAP as a useful tool in COVID-19 related Acute Hypoxemic Respiratory Failure: Experience from 3 UK Hospitals (preprint)

Introduction: Severe acute hypoxemic respiratory failure (AHRF) in COVID-19 pneumonia is associated with a high mortality rate, resulting in mounting pressures on intensive care units worldwide. Different oxygenation management protocols are used in different centres. Most centres switch patients who fail to oxygenate adequately using conventional oxygen therapy (COT) methods to non-invasive positive pressure ventilation (NIPPV), usually continuous positive airway pressure (CPAP). Other centres resort to invasive mechanical ventilation (IMV) directly, without a trial of NIPPV. In this trial, we aim to compare the efficacy of different approaches in managing COVID-related AHRF, and ascertain if CPAP therapy reduces the need for IMV. Methods: We carried out a retrospective cohort study on patients with laboratory-confirmed COVID-19 at three university hospitals in Essex, United Kingdom. We included all patients with significant AHRF (defined as needing oxygen therapy FiO2 more than 0.4 to maintain an oxygen saturation of 92%) who were deemed eligible for IMV escalation during a 3-month period (1st March to 31st May 2020).Results: Out of 174 patients who met the criteria, 84 patients received CPAP (Group 1). Half needed intubation (n=42). 90 patients did not have a CPAP trial (Group 2). 76.6% needed intubation (n=69). No difference was found between the two groups in demographic criteria or disease severity. Our results show a significant difference in 60-day mortality between group 1 and 2 (25% versus 37.8%, p=0.02). COT as standalone therapy for COVID-19 patients (group 2) was associated with a trend of more increased risk of intubation and an increased relative risk of death (RR 2.14, 95% CI 1.39 to 3.29). This corresponds to a number needed to treat (NNT) of 3.74 (95% CI 2.47 to 7.73). Patients in group 1 who failed CPAP trial and required intubation did not have an increased risk of mortality when compared to group 2 patients who required intubation.Conclusion: Our results support introducing CPAP rather than escalating FiO2 in cases refractory to COT. Our study suggests CPAP can be safely used to treat patients with AHRF. Clinical trials are needed to guide recommendations for optimum timing and selection of patients most likely to benefit.

Components of a safe cystectomy service during coronavirus disease 2019 in a high-volume centre

Objective: Delivery of a safe cystectomy service is a multidisciplinary exercise. In this article, we detail the measures implemented at our institution to deliver a cystectomy service for bladder cancer patients during coronavirus disease 2019 (COVID-19). Methods: A ‘one-stop’ enhanced recovery clinic had been established at our hospital, consisting of an anaesthetist, an exercise testing service, urinary diversion nurses, clinical nurse specialists and surgeons. During COVID-19, we modified these processes in order to continue to provide urgent cystectomy safely for bladder cancer. We collected patients’ outcomes prospectively measuring demographic characteristics, oncological and perioperative outcomes, the presence of COVID-19 symptoms and confirmed COVID-19 test results. Results: From March to May 2020, 25 patients underwent radical cystectomy for bladder cancer. Twenty-four procedures were performed with robotic assistance and one open as part of a research trial. We instituted modifications at various multidisciplinary steps, including patient selection, preoperative optimisation, enhanced recovery protocols, patient counselling and perioperative protocols. Thirty-day mortality was 0%. The 30-day rate of Clavien ⩾3 complications was 8%. Postoperatively, none of the patients developed COVID-19 based on World Health Organization criteria and testing. Conclusion: We safely delivered a complex cystectomy service during the peak of the COVID-19 pandemic without any COVID-19-related morbidity or mortality. Level of evidence: Level 2b.

Genetically Modified Mesenchymal Stromal/Stem Cells: Application in Critical Illness.

Critical illnesses including sepsis, acute respiratory distress syndromes, ischemic cardiovascular disorders and acute organ injuries are associated with high mortality, morbidity as well as significant health care system expenses. While these diverse conditions require different specific therapeutic approaches, mesenchymal stem/stromal cell (MSCs) are multipotent cells capable of self-renewal, tri-lineage differentiation with a broad range regenerative and immunomodulatory activities, making them attractive for the treatment of critical illness. The therapeutic effects of MSCs have been extensively investigated in several pre-clinical models of critical illness as well as in phase I and II clinical cell therapy trials with mixed results. Whilst these studies have demonstrated the therapeutic potential for MSC therapy in critical illness, optimization for clinical use is an ongoing challenge. MSCs can be readily genetically modified by application of different techniques and tools leading to overexpress or inhibit genes related to their immunomodulatory or regenerative functions. Here we will review recent approaches designed to enhance the therapeutic potential of MSCs with an emphasis on the technology used to generate genetically modified cells, target genes, target diseases and the implication of genetically modified MSCs in cell therapy for critical illness.

Estimating the effect of physical distancing on the COVID-19 pandemic using an urban mobility index (preprint)

Background: Governments have implemented population-wide physical distancing measures to control COVID-19, but metrics evaluating their effectiveness are not readily available. Methods: We used a publicly available mobility index from a popular transit application to evaluate the effect of physical distancing on infection growth rates and reproductive numbers in 40 jurisdictions between March 23 and April 12, 2020. Findings: A 10% decrease in mobility was associated with a 14.6% decrease (exp({beta}) = 0.854; 95% credible interval: 0.835, 0.873) in the average daily growth rate and a -0.061 (95% CI: -0.071, -0.052) change in the instantaneous reproductive number two weeks later. Interpretation: Our analysis demonstrates that decreases in urban mobility were predictive of declines in epidemic growth. Mobility metrics offer an appealing method to calibrate population-level physical distancing policy and implementation, especially as jurisdictions relax restrictions and consider alternative physical distancing strategies. Funding: No external funding was received for this study.