Structural Predictors of Lung Function Decline in Young Smokers with Normal Spirometry.

Rationale: Chronic obstructive pulmonary disease (COPD) due to tobacco smoking commonly presents when extensive lung damage has occurred. Objectives: We hypothesized that structural change would be detected early in the natural history of COPD and would relate to loss of lung function with time. Methods: We recruited 431 current smokers (median age, 39 yr; 16 pack-years smoked) and recorded symptoms using the COPD Assessment Test (CAT), spirometry, and quantitative thoracic computed tomography (QCT) scans at study entry. These scan results were compared with those from 67 never-smoking control subjects. Three hundred sixty-eight participants were followed every six months with measurement of postbronchodilator spirometry for a median of 32 months. The rate of FEV1 decline, adjusted for current smoking status, age, and sex, was related to the initial QCT appearances and symptoms, measured using the CAT. Measurements and Main Results: There were no material differences in demography or subjective CT appearances between the young smokers and control subjects, but 55.7% of the former had CAT scores greater than 10, and 24.2% reported chronic bronchitis. QCT assessments of disease probability-defined functional small airway disease, ground-glass opacification, bronchovascular prominence, and ratio of small blood vessel volume to total pulmonary vessel volume were increased compared with control subjects and were all associated with a faster FEV1 decline, as was a higher CAT score. Conclusions: Radiological abnormalities on CT are already established in young smokers with normal lung function and are associated with FEV1 loss independently of the impact of symptoms. Structural abnormalities are present early in the natural history of COPD and are markers of disease progression. Clinical trial registered with www.clinicaltrials.gov (NCT03480347).

Cytokine biomarkers of exacerbations in sputum from Chronic Obstructive Pulmonary Disease patients: a prospective cohort study.

BACKGROUND: We determined the relationships between cytokine expression in sputum and clinical data to characterise and understand Chronic Obstructive Pulmonary Disease (COPD) exacerbations in COPD patients. METHODS: We measured 30 cytokines in 936 sputum samples, collected at stable state (ST) and exacerbation (EX) visits from 99 participants in the Acute Exacerbation and Respiratory InfectionS in COPD (AERIS) study (NCT01360398, www.clinicaltrials.gov). We determined their longitudinal expression and examined differential expression based on disease status or exacerbation type. RESULTS: Of the cytokines, 17 were suitable for analysis. As for disease states, in EX sputum samples, IL-17A, TNF-α, IL-1ß, and IL-10 were significantly increased compared to ST sputum samples, but a logistic mixed model could not predict disease state. As for exacerbation types, bacteria-associated exacerbations showed higher expression of IL-17A, TNF-α, IL-1ß, and IL-1α. IL-1α, IL-1ß, and TNF-α were identified as suitable biomarkers for bacteria-associated exacerbation. Bacteria-associated exacerbations also formed a cluster separate from other exacerbation types in principal component analysis. CONCLUSIONS: Measurement of cytokines in sputum from COPD patients could help identify bacteria-associated exacerbations based on increased concentrations of IL-1α, IL-1ß, or TNF-α. This finding may provide a point-of-care assessment to distinguish a bacterial exacerbation of COPD from other exacerbation types.

Immunopeptidomic analysis of influenza A virus infected human tissues identifies internal proteins as a rich source of HLA ligands.

CD8+ and CD4+ T cells provide cell-mediated cross-protection against multiple influenza strains by recognising epitopes bound as peptides to human leukocyte antigen (HLA) class I and -II molecules respectively. Two challenges in identifying the immunodominant epitopes needed to generate a universal T cell influenza vaccine are: A lack of cell models susceptible to influenza infection which present population-prevalent HLA allotypes, and an absence of a reliable in-vitro method of identifying class II HLA peptides. Here we present a mass spectrometry-based proteomics strategy for identifying viral peptides derived from the A/H3N2/X31 and A/H3N2/Wisconsin/67/2005 strains of influenza. We compared the HLA-I and -II immunopeptidomes presented by ex-vivo influenza challenged human lung tissues. We then compared these with directly infected immortalised macrophage-like cell line (THP1) and primary dendritic cells fed apoptotic influenza-infected respiratory epithelial cells. In each of the three experimental conditions we identified novel influenza class I and II HLA peptides with motifs specific for the host allotype. Ex-vivo infected lung tissues yielded few class-II HLA peptides despite significant numbers of alveolar macrophages, including directly infected ones, present within the tissues. THP1 cells presented HLA-I viral peptides derived predominantly from internal proteins. Primary dendritic cells presented predominantly viral envelope-derived HLA class II peptides following phagocytosis of apoptotic infected cells. The most frequent viral source protein for HLA-I and -II was matrix 1 protein (M1). This work confirms that internal influenza proteins, particularly M1, are a rich source of CD4+ and CD8+ T cell epitopes. Moreover, we demonstrate the utility of two ex-vivo fully human infection models which enable direct HLA-I and -II immunopeptide identification without significant viral tropism limitations. Application of this epitope discovery strategy in a clinical setting will provide more certainty in rational vaccine design against influenza and other emergent viruses.

Single-arm, first-in-human feasibility study results for an ultra-low-cost insulin pump.

BACKGROUND: Use of Continuous Subcutaneous Insulin Infusion (CSII) has been shown to improve glycemic outcomes in Type 1 Diabetes (T1D), but high costs limit accessibility. To address this issue, an inter-operable, open-source Ultra-Low-Cost Insulin Pump (ULCIP) was developed and previously shown to demonstrate comparable delivery accuracy to commercial models in standardised laboratory tests. This study aims to evaluate the updated ULCIP in-vivo, assessing its viability as an affordable alternative for those who cannot afford commercially available devices. METHODS: This first-in-human feasibility study recruited six participants with T1D. During a nine-hour inpatient stay, participants used the ULCIP under clinical supervision. Venous glucose, insulin, and ß-Hydroxybutyrate were monitored to assess device performance. RESULTS: Participants displayed expected blood glucose and blood insulin levels in response to programmed basal and bolus insulin dosing. One participant developed mild ketosis, which was treated and did not recur when a new pump reservoir was placed. All other participants maintained ß-Hydroxybutyrate < 0.6 mmol/L throughout. CONCLUSION: The ULCIP safely delivered insulin therapy to users in a supervised inpatient environment. Future work should focus on correcting a pump hardware issue identified in this trial and extending device capabilities for use in closed loop control. Longer-term outpatient studies are warranted. TRIAL REGISTRATION: The trial was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12623001288617) on the 11 December 2023.

Antiviral Responses of Tissue-resident CD49a+ Lung Natural Killer Cells Are Dysregulated in Chronic Obstructive Pulmonary Disease.

Rationale: Tissue-resident natural killer (trNK) cells have been identified in numerous organs, but little is known about their functional contribution to respiratory immunity, in particular during chronic lung diseases such as chronic obstructive pulmonary disease (COPD). Objectives: To investigate the phenotype and antiviral responses of trNK cells in murine cigarette smoke-induced experimental COPD and in human lung parenchyma from COPD donors. Methods: Mice were exposed to cigarette smoke for 12 weeks to induce COPD-like lung disease. Lung trNK cell phenotypes and function were analyzed by flow cytometry in both murine and human disease with and without challenge with influenza A virus. Measurements and Main Results: In the mouse lung, CD49a+CD49b+EOMES+ and CD49a+CD49b-EOMESlo NK cell populations had a distinct phenotype compared with CD49a- circulating NK cells. CD49a+ NK cells were more extensively altered earlier in disease onset than circulating NK cells, and increased proportions of CD49a+ NK cells correlated with worsening disease in both murine and human COPD. Furthermore, the presence of lung disease delayed both circulating and trNK cell functional responses to influenza infection. CD49a+ NK cells markedly increased their NKG2D, CD103, and CD69 expression in experimental COPD after influenza infection, and human CD49a+ NK cells were hyperactive to ex vivo influenza infection in COPD donors. Conclusions: Collectively, these results demonstrate that trNK cell function is altered in cigarette smoke-induced disease and suggests that smoke exposure may aberrantly prime trNK cell responsiveness to viral infection. This may contribute to excess inflammation during viral exacerbations of COPD.

The utility of rested prolactin sampling in the evaluation of hyperprolactinaemia.

BACKGROUND AND AIMS: Serum prolactin levels may be elevated by venepuncture stress. We investigated the utility of a rested prolactin sample, obtained through an indwelling venous cannula, in preventing the overdiagnosis of hyperprolactinaemia. METHODS: Patients at our institution undergo serial prolactin sampling, usually over 40 min, when investigating hyperprolactinaemia. We retrospectively reviewed all serial prolactin sampling performed during a 3-year period. Patients with possible medication-induced hyperprolactinaemia and macroprolactin interference were excluded. We assessed the effect of venepuncture-associated stress on hyperprolactinaemia with the main outcome being normalisation of serum prolactin at the end of serial sampling. RESULTS: Ninety-three patients with documented hyperprolactinaemia (range 360-1690 mU/L) were included in the analysis. Prolactin decreased during serial sampling in 73 patients (78%), suggesting a prevalent effect of venepuncture stress. The final prolactin sample was normal in 50 patients (54%), consistent with stress hyperprolactinaemia rather than pathological hyperprolactinaemia. Patients with a referral prolactin result greater than two times the upper reference limit (URL) were less likely (15%) to have a normal prolactin result on serial sampling. Measurement of a single rested prolactin sample from an indwelling cannula showed the same diagnostic utility as serial sampling. CONCLUSION: Serum prolactin results are frequently elevated by the stress of venepuncture. Confirmation of pathological hyperprolactinaemia in a rested sample obtained from an indwelling venous cannula is recommended in patients with mild hyperprolactinaemia, particularly when the referral prolactin is less than two times the URL.

Biomarkers of tissue remodelling are elevated in serum of COVID-19 patients who develop interstitial lung disease - an exploratory biomarker study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a viral pneumonia that can result in serious respiratory illness. It is associated with extensive systemic inflammation, changes to the lung extracellular matrix, and long-term lung impairment such as interstitial lung disease (ILD). In this study, the aim was to investigate whether tissue remodelling, wound healing, and neutrophil activity is altered in patients with COVID-19 and how these relate to the development of post-COVID ILD. METHOD: Serum samples were collected from 63 patients three months after discharge as part of the Research Evaluation Alongside Clinical Treatment study in COVID-19 (REACT COVID-19), 10 of whom developed ILD, and 16 healthy controls. Samples were quantified using neo-epitope specific biomarkers reflecting tissue stiffness and formation (PC3X, PRO-C3, and PRO-C6), tissue degradation (C1M, C3M, and C6M), wound healing (PRO-FIB and X-FIB), and neutrophil activity (CPa9-HNE and ELP-3). RESULTS: Mean serum levels of PC3X (p < 0.0001), PRO-C3 (p = 0.002), C3M (p = 0.009), PRO-FIB (p < 0.0001), CPa9-HNE (p < 0.0001), and ELP-3 (p < 0.0001) were significantly elevated in patients with COVID-19 compared to healthy controls. Moreover, PC3X (p = 0.023) and PRO-C3 (p = 0.032) were significantly elevated in post-COVID ILD as compared to COVID-19. CONCLUSION: Serological biomarkers reflecting type III collagen remodelling, clot formation, and neutrophil activity were significantly elevated in COVID-19 and type III collagen formation markers were further elevated in post-COVID ILD. The findings suggest an increased type III collagen remodelling in COVID-19 and warrants further investigations to assess the potential of tissue remodelling biomarkers as a tool to identify COVID-19 patients at high risk of developing ILD.

Remote Patient Monitoring and Machine Learning in Acute Exacerbations of Chronic Obstructive Pulmonary Disease: Dual Systematic Literature Review and Narrative Synthesis.

BACKGROUND: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are associated with high mortality, morbidity, and poor quality of life and constitute a substantial burden to patients and health care systems. New approaches to prevent or reduce the severity of AECOPD are urgently needed. Internationally, this has prompted increased interest in the potential of remote patient monitoring (RPM) and digital medicine. RPM refers to the direct transmission of patient-reported outcomes, physiological, and functional data, including heart rate, weight, blood pressure, oxygen saturation, physical activity, and lung function (spirometry), directly to health care professionals through automation, web-based data entry, or phone-based data entry. Machine learning has the potential to enhance RPM in chronic obstructive pulmonary disease by increasing the accuracy and precision of AECOPD prediction systems. OBJECTIVE: This study aimed to conduct a dual systematic review. The first review focuses on randomized controlled trials where RPM was used as an intervention to treat or improve AECOPD. The second review examines studies that combined machine learning with RPM to predict AECOPD. We review the evidence and concepts behind RPM and machine learning and discuss the strengths, limitations, and clinical use of available systems. We have generated a list of recommendations needed to deliver patient and health care system benefits. METHODS: A comprehensive search strategy, encompassing the Scopus and Web of Science databases, was used to identify relevant studies. A total of 2 independent reviewers (HMGG and CM) conducted study selection, data extraction, and quality assessment, with discrepancies resolved through consensus. Data synthesis involved evidence assessment using a Critical Appraisal Skills Programme checklist and a narrative synthesis. Reporting followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RESULTS: These narrative syntheses suggest that 57% (16/28) of the randomized controlled trials for RPM interventions fail to achieve the required level of evidence for better outcomes in AECOPD. However, the integration of machine learning into RPM demonstrates promise for increasing the predictive accuracy of AECOPD and, therefore, early intervention. CONCLUSIONS: This review suggests a transition toward the integration of machine learning into RPM for predicting AECOPD. We discuss particular RPM indices that have the potential to improve AECOPD prediction and highlight research gaps concerning patient factors and the maintained adoption of RPM. Furthermore, we emphasize the importance of a more comprehensive examination of patient and health care burdens associated with RPM, along with the development of practical solutions.

Smaller Biceps Femoris Aponeurosis Size in Legs with a History of Hamstring Strain Injury.

Biceps femoris long head (BFLH) aponeurosis size was compared between legs with and without prior hamstring strain injury (HSI) using two approaches: within-group (injured vs. uninjured legs of previous unilateral HSI athletes) and between-group (previously injured legs of HSI athletes vs. legs of No Prior HSI athletes). MRI scans were performed on currently healthy, competitive male athletes with Prior HSI history (n=23;≥1 verified BFLH injury; including a sub-group with unilateral HSI history; most recent HSI 1.6±1.2 years ago) and pair-matched athletes with No Prior HSI history (n=23). Anonymized axial images were manually segmented to quantify BFLH aponeurosis and muscle size. Prior unilateral HSI athletes' BFLH aponeurosis maximum width, aponeurosis area, and aponeurosis:muscle area ratio were 14.0-19.6% smaller in previously injured vs. contralateral uninjured legs (paired t-test, 0.008≤P≤0.044). BFLH aponeurosis maximum width and area were also 9.4-16.5% smaller in previously injured legs (n=28) from Prior HSI athletes vs. legs (n=46) of No Prior HSI athletes (unpaired t-test, 0.001≤P≤0.044). BFLH aponeurosis size was smaller in legs with prior HSI vs. those without prior HSI. These findings suggest BFLH aponeurosis size, especially maximum width, could be a potential cause or consequence of HSI, with prospective evidence needed to support or refute these possibilities.

Simultaneous Optimization of MP2RAGE T1 -weighted (UNI) and FLuid And White matter Suppression (FLAWS) brain images at 7T using Extended Phase Graph (EPG) Simulations.

PURPOSE: The MP2RAGE sequence is typically optimized for either T1 -weighted uniform image (UNI) or gray matter-dominant fluid and white matter suppression (FLAWS) contrast images. Here, the purpose was to optimize an MP2RAGE protocol at 7 Tesla to provide UNI and FLAWS images simultaneously in a clinically applicable acquisition time at <0.7 mm isotropic resolution. METHODS: Using the extended phase graph formalism, the signal evolution of the MP2RAGE sequence was simulated incorporating T2 relaxation, diffusion, RF spoiling, and B1 + variability. Flip angles and TI were optimized at different TRs (TRMP2RAGE ) to produce an optimal contrast-to-noise ratio for UNI and FLAWS images. Simulation results were validated by comparison to MP2RAGE brain scans of 5 healthy subjects, and a final protocol at TRMP2RAGE  = 4000 ms was applied in 19 subjects aged 8-62 years with and without epilepsy. RESULTS: FLAWS contrast images could be obtained while maintaining >85% of the optimal UNI contrast-to-noise ratio. Using TI1 /TI2 /TRMP2RAGE of 650/2280/4000 ms, 6/8 partial Fourier in the inner phase-encoding direction, and GRAPPA factor = 4 in the other, images with 0.65 mm isotropic resolution were produced in <7.5 min. The contrast-to-noise ratio was around 20% smaller at TRMP2RAGE  = 4000 ms compared to that at TRMP2RAGE  = 5000 ms; however, the 20% shorter duration makes TRMP2RAGE  = 4000 ms a good candidate for clinical applications example, pediatrics. CONCLUSION: FLAWS and UNI images could be obtained in a single scan with 0.65 mm isotropic resolution, providing a set of high-contrast images and full brain coverage in a clinically applicable scan time. Images with excellent anatomical detail were demonstrated over a wide age range using the optimized parameter set.

Inhaled nebulised unfractionated heparin (UFH) for the treatment of hospitalised patients with COVID-19: A randomised controlled pilot study.

There is a strong scientific rationale to use nebulised unfractionated heparin (UFH) in treating patients with COVID-19. This pilot study investigated whether nebulised UFH was safe and had any impact on mortality, length of hospitalisation and clinical progression, in the treatment of hospitalised patients with COVID-19. This parallel group, open label, randomised trial included adult patients with confirmed SARS-CoV-2 infection admitted to two hospitals in Brazil. One hundred patients were planned to be randomised to either "standard of care" (SOC) or SOC plus nebulized UFH. The trial was stopped after randomisation of 75 patients due to falling COVID-19 hospitalisation rates. Significance tests were 1-sided test (10% significance level). The key analysis populations were intention to treat (ITT) and modified ITT (mITT) which excluded (from both arms) subjects admitted to ITU or who died within 24 h of randomisation. In the ITT population (n = 75), mortality was numerically lower for nebulised UFH (6 out of 38 patients; 15.8%) versus SOC (10 out of 37 patients; 27.0%), but not statistically significant; odds ratio (OR) 0.51, p = 0.24. However, in the mITT population, nebulised UFH reduced mortality (OR 0.2, p = 0.035). Length of hospital stay was similar between groups, but at day 29, there was a greater improvement in ordinal score following treatment with UFH in the ITT and mITT populations (p = 0.076 and p = 0.012 respectively), while mechanical ventilation rates were lower with UFH in the mITT population (OR 0.31; p = 0.08). Nebulised UFH did not cause any significant adverse events. In conclusion, nebulised UFH added to SOC in hospitalised patients with COVID-19 was well tolerated and showed clinical benefit, particularly in patients who received at least 6 doses of heparin. This trial was funded by The J.R. Moulton Charity Trust and registered under REBEC RBR-8r9hy8f (UTN code: U1111-1263-3136).

Towards an artificial human lung: modelling organ-like complexity to aid mechanistic understanding.

Respiratory diseases account for over 5 million deaths yearly and are a huge burden to healthcare systems worldwide. Murine models have been of paramount importance to decode human lung biology in vivo, but their genetic, anatomical, physiological and immunological differences with humans significantly hamper successful translation of research into clinical practice. Thus, to clearly understand human lung physiology, development, homeostasis and mechanistic dysregulation that may lead to disease, it is essential to develop models that accurately recreate the extraordinary complexity of the human pulmonary architecture and biology. Recent advances in micro-engineering technology and tissue engineering have allowed the development of more sophisticated models intending to bridge the gap between the native lung and its replicates in vitro Alongside advanced culture techniques, remarkable technological growth in downstream analyses has significantly increased the predictive power of human biology-based in vitro models by allowing capture and quantification of complex signals. Refined integrated multi-omics readouts could lead to an acceleration of the translational pipeline from in vitro experimental settings to drug development and clinical testing in the future. This review highlights the range and complexity of state-of-the-art lung models for different areas of the respiratory system, from nasal to large airways, small airways and alveoli, with consideration of various aspects of disease states and their potential applications, including pre-clinical drug testing. We explore how development of optimised physiologically relevant in vitro human lung models could accelerate the identification of novel therapeutics with increased potential to translate successfully from the bench to the patient's bedside.

Parallel transmit pulse design for saturation homogeneity (PUSH) for magnetization transfer imaging at 7T.

PURPOSE: This work proposes a novel RF pulse design for parallel transmit (pTx) systems to obtain uniform saturation of semisolid magnetization for magnetization transfer (MT) contrast in the presence of transmit field B1+ inhomogeneities. The semisolid magnetization is usually modeled as being purely longitudinal, with the applied B1+ field saturating but not rotating its magnetization; thus, standard pTx pulse design methods do not apply. THEORY AND METHODS: Pulse design for saturation homogeneity (PUSH) optimizes pTx RF pulses by considering uniformity of root-mean squared B1+ , B1rms , which relates to the rate of semisolid saturation. Here we considered designs consisting of a small number of spatially non-selective sub-pulses optimized over either a single 2D plane or 3D. Simulations and in vivo experiments on a 7T Terra system with an 8-TX Nova head coil in five subjects were carried out to study the homogenization of B1rms and of the MT contrast by acquiring MT ratio maps. RESULTS: Simulations and in vivo experiments showed up to six and two times more uniform B1rms compared to circular polarized (CP) mode for 2D and 3D optimizations, respectively. This translated into 4 and 1.25 times more uniform MT contrast, consistently for all subjects, where two sub-pulses were enough for the implementation and coil used. CONCLUSION: The proposed PUSH method obtains more uniform and higher MT contrast than CP mode within the same specific absorption rate (SAR) budget.

COVID-19 and the long-term cardio-respiratory and metabolic health complications.

Severe acute respiratory syndrome coronavirus type-2 (SARS-CoV-2) transmission continues to impact people globally. Whilst the acute symptoms and management strategies are well documented, millions of people globally are experiencing a prolonged and debilitating symptom profile that is reported to last months and even years. COVID-19 is a multi-system disease however the magnitude of the effects and its associated legacy is presently not well understood. Early reports indicate that multidisciplinary approaches between clinical and non-clinical entities are needed to provide effective and rehabilitative patient support pathways and restore pre-COVID-19 quality of life and functional status. Accordingly, this review provides a summary of the impact on cardiovascular, inflammatory, respiratory, and musculoskeletal function following an acute COVID-19 infection along with the prolonged effects of long-COVID.

Nontypeable Haemophilus influenzae infection of pulmonary macrophages drives neutrophilic inflammation in severe asthma.

BACKGROUND: Nontypeable Haemophilus influenzae (NTHi) is a respiratory tract pathobiont that chronically colonizes the airways of asthma patients and is associated with severe, neutrophilic disease phenotypes. The mechanism of NTHi airway persistence is not well understood, but accumulating evidence suggests NTHi can persist within host airway immune cells such as macrophages. We hypothesized that NTHi infection of pulmonary macrophages drives neutrophilic inflammation in severe asthma. METHODS: Bronchoalveolar lavage (BAL) samples from 25 severe asthma patients were assessed by fluorescence in situ hybridisation to quantify NTHi presence. Weighted gene correlation network analysis (WGCNA) was performed on RNASeq data from NTHi-infected monocyte-derived macrophages to identify transcriptomic networks associated with NTHi infection. RESULTS: NTHi was detected in 56% of BAL samples (NTHi+) and was associated with longer asthma duration (34 vs 22.5 years, p = .0436) and higher sputum neutrophil proportion (67% vs 25%, p = .0462). WGCNA identified a transcriptomic network of immune-related macrophage genes significantly associated with NTHi infection, including upregulation of T17 inflammatory mediators and neutrophil chemoattractants IL1B, IL8, IL23 and CCL20 (all p < .05). Macrophage network genes SGPP2 (p = .0221), IL1B (p = .0014) and GBP1 (p = .0477) were more highly expressed in NTHi+ BAL and moderately correlated with asthma duration (IL1B; rho = 0.41, p = .041) and lower prebronchodilator FEV1/FVC% (GBP1; rho = -0.43, p = .046 and IL1B; rho = -0.42, p = .055). CONCLUSIONS: NTHi persistence with pulmonary macrophages may contribute to chronic airway inflammation and T17 responses in severe asthma, which can lead to decreased lung function and reduced steroid responsiveness. Identifying therapeutic strategies to reduce the burden of NTHi in asthma could improve patient outcomes.

Inflammation and physical dysfunction: responses to moderate intensity exercise in chronic kidney disease.

BACKGROUND: People with chronic kidney disease (CKD) experience skeletal muscle wasting, reduced levels of physical function and performance, and chronic systemic inflammation. While it is known that a relationship exists between inflammation and muscle wasting, the association between inflammation and physical function or performance in CKD has not been well studied. Exercise has anti-inflammatory effects, but little is known regarding the effect of moderate intensity exercise. This study aimed to (i) compare systemic and intramuscular inflammation between CKD stage G3b-5 and non-CKD controls; (ii) establish whether a relationship exists between physical performance, exercise capacity and inflammation in CKD; (iii) determine changes in systemic and intramuscular inflammation following 12 weeks of exercise; and (iv) investigate whether improving inflammatory status via training contributes to improvements in physical performance and muscle mass. METHODS: This is a secondary analysis of previously collected data. CKD patients stages G3b-5 (n = 84, n = 43 males) and non-CKD controls (n = 26, n = 17 males) underwent tests of physical performance, exercise capacity, muscle strength and muscle size. In addition, a subgroup of CKD participants underwent 12 weeks of exercise training, randomized to aerobic (AE, n = 21) or combined (CE, n = 20) training. Plasma and intramuscular inflammation and myostatin were measured at rest and following exercise. RESULTS: Tumour necrosis factor-α was negatively associated with lower $^{^{^{.}}}{\rm V}$O2Peak (P = 0.01), Rectus femoris-cross sectional area (P = 0.002) and incremental shuttle walk test performance (P < 0.001). Interleukin-6 was negatively associated with sit-to-stand 60 performances (P = 0.006) and hand grip strength (P = 0.001). Unaccustomed exercise created an intramuscular inflammatory response that was attenuated following 12 weeks of training. Exercise training did not reduce systemic inflammation, but AE training did significantly reduce mature myostatin levels (P = 0.02). Changes in inflammation were not associated with changes in physical performance. CONCLUSIONS: Systemic inflammation may contribute to reduced physical function in CKD. Twelve weeks of exercise training was unable to reduce the level of chronic systemic inflammation in these patients, but did reduce plasma myostatin concentrations. Further research is required to further investigate this.

Inflammatory Endotype-associated Airway Microbiome in Chronic Obstructive Pulmonary Disease Clinical Stability and Exacerbations: A Multicohort Longitudinal Analysis.

Rationale: Understanding the role of the airway microbiome in chronic obstructive pulmonary disease (COPD) inflammatory endotypes may help to develop microbiome-based diagnostic and therapeutic approaches. Objectives: To understand the association of the airway microbiome with neutrophilic and eosinophilic COPD at stability and during exacerbations. Methods: An integrative analysis was performed on 1,706 sputum samples collected longitudinally from 510 patients with COPD recruited at four UK sites of the BEAT-COPD (Biomarkers to Target Antibiotic and Systemic COPD), COPDMAP (Chronic Obstructive Pulmonary Disease Medical Research Council/Association of the British Pharmaceutical Industry), and AERIS (Acute Exacerbation and Respiratory Infections in COPD) cohorts. The microbiome was analyzed using COPDMAP and AERIS as a discovery data set and BEAT-COPD as a validation data set. Measurements and Main Results: The airway microbiome in neutrophilic COPD was heterogeneous, with two primary community types differentiated by the predominance of Haemophilus. The Haemophilus-predominant subgroup had elevated sputum IL-1ß and TNFα (tumor necrosis factor α) and was relatively stable over time. The other neutrophilic subgroup with a balanced microbiome profile had elevated sputum and serum IL-17A and was temporally dynamic. Patients in this state at stability were susceptible to the greatest microbiome shifts during exacerbations. This subgroup can temporally switch to both neutrophilic Haemophilus-predominant and eosinophilic states that were otherwise mutually exclusive. Time-series analysis on the microbiome showed that the temporal trajectories of Campylobacter and Granulicatella were indicative of intrapatient switches from neutrophilic to eosinophilic inflammation, in track with patient sputum eosinophilia over time. Network analysis revealed distinct host-microbiome interaction patterns among neutrophilic Haemophilus-predominant, neutrophilic balanced microbiome, and eosinophilic subgroups. Conclusions: The airway microbiome can stratify neutrophilic COPD into subgroups that justify different therapies. Neutrophilic and eosinophilic COPD are interchangeable in some patients. Monitoring temporal variability of the airway microbiome may track patient inflammatory status over time.

Biomarkers to guide the use of antibiotics for acute exacerbations of COPD (AECOPD): a systematic review and meta-analysis.

BACKGROUND: Antibiotics are frequently prescribed for acute exacerbations of COPD (AECOPD) even though most do not have a bacterial aetiology. Biomarkers may help clinicians target antibiotic use by identifying AECOPD caused by bacterial pathogens. We aimed to summarise current evidence on the diagnostic accuracy of biomarkers for detecting bacterial versus non-bacterial AECOPD. METHODS: We searched Embase and Medline using a search strategy including terms for COPD, biomarkers and bacterial infection. Data regarding diagnostic accuracy for each biomarker in predicting bacterial cause of exacerbation were extracted and summarised. We used to QUADAS-2 tool to assess risk of bias. RESULTS: Of 509 papers identified, 39 papers evaluating 61 biomarkers were eligible for inclusion. Moderate quality evidence was found for associations between serum C-reactive protein (CRP), serum procalcitonin (PCT), sputum interleukin (IL)-8 and sputum tumour necrosis factor alpha (TNF-α), and the presence of bacterial pathogens in the sputum of patients with AECOPD. Having bacterial pathogens was associated with a mean difference (higher) CRP and PCT of 29.44 mg/L and 0.76 ng/mL respectively. There was inconsistent or weak evidence for associations between bacterial AECOPD and higher levels of sputum IL-1ß, IL-6, myeloperoxidase (MPO) and neutrophil elastase (NE). We did not find any consistent evidence of diagnostic value for other biomarkers. CONCLUSIONS: There is moderate evidence from heterogeneous studies that serum CRP and PCT are of value in differentiating bacterial from non-bacterial AECOPD, and little evidence for other biomarkers. Further high-quality research on the role of biomarkers in identifying bacterial exacerbations is needed.

Sputum sample positivity for Haemophilus influenzae or Moraxella catarrhalis in acute exacerbations of chronic obstructive pulmonary disease: evaluation of association with positivity at earlier stable disease timepoints.

BACKGROUND: Infection with Haemophilus influenzae (Hi) or Moraxella catarrhalis (Mcat) is a risk factor for exacerbation in chronic obstructive pulmonary disease (COPD). The ability to predict Hi- or Mcat-associated exacerbations may be useful for interventions developed to reduce exacerbation frequency. METHODS: In a COPD observational study, sputum samples were collected at monthly stable-state visits and at exacerbation during two years of follow-up. Bacterial species (Hi, Mcat) were identified by culture and quantitative PCR assay. Post-hoc analyses were conducted to assess: (1) first Hi- or Mcat-positive exacerbations given presence or absence of Hi or Mcat at the screening visit (stable-state timepoint); (2) first Hi- or Mcat-positive exacerbations given presence or absence of Hi or Mcat at stable timepoints within previous 90 days; (3) second Hi- or Mcat-positive exacerbations given presence or absence of Hi or Mcat at stable timepoints within previous 90 days. Percentages and risk ratios (RRs) with 95% confidence intervals were calculated. RESULTS: PCR results for analyses 1, 2 and 3 (samples from 84, 88 and 83 subjects, respectively) showed that the risk of an Hi- or Mcat-positive exacerbation is significantly higher if sputum sample was Hi- or Mcat-positive than if Hi- or Mcat-negative at previous stable timepoints (apart from Mcat in analysis 3); RRs ranged from 2.1 to 3.2 for Hi and 1.9 to 2.6 for Mcat.For all analyses, the percentage of Hi- or Mcat-positive exacerbations given previous Hi- or Mcat-positive stable timepoints was higher than the percentage of Hi- or Mcat-positive exacerbations if Hi- or Mcat-negative at previous stable timepoints. Percentage of Hi- or Mcat-positive exacerbations given previous Hi- or Mcat-negative stable timepoints was 26.3%-37.0% for Hi and 17.6%-19.7% for Mcat. CONCLUSIONS: Presence of Hi or Mcat at a stable timepoint was associated with a higher risk of a subsequent Hi- or Mcat-associated exacerbation compared with earlier absence. However, a large percentage of Hi- or Mcat-associated exacerbations was not associated with Hi/Mcat detection at an earlier timepoint. This suggests that administration of an intervention to reduce these exacerbations should be independent of bacterial presence at baseline. Trial Registration https://clinicaltrials.gov/ ; NCT01360398, registered May 25, 2011.

Dysregulation of COVID-19 related gene expression in the COPD lung.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) patients are at increased risk of poor outcome from Coronavirus disease (COVID-19). Early data suggest elevated Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) receptor angiotensin converting enzyme 2 (ACE2) expression, but relationships to disease phenotype and downstream regulators of inflammation in the Renin-Angiotensin system (RAS) are unknown. We aimed to determine the relationship between RAS gene expression relevant to SARS-CoV-2 infection in the lung with disease characteristics in COPD, and the regulation of newly identified SARS-CoV-2 receptors and spike-cleaving proteases, important for SARS-CoV-2 infection. METHODS: We quantified gene expression using RNA sequencing of epithelial brushings and bronchial biopsies from 31 COPD and 37 control subjects. RESULTS: ACE2 gene expression (log2-fold change (FC)) was increased in COPD compared to ex-smoking (HV-ES) controls in epithelial brushings (0.25, p = 0.042) and bronchial biopsies (0.23, p = 0.050), and correlated with worse lung function (r = - 0.28, p = 0.0090). ACE2 was further increased in frequent exacerbators compared to infrequent exacerbators (0.51, p = 0.00045) and associated with use of ACE inhibitors (ACEi) (0.50, p = 0.0034), having cardiovascular disease (0.23, p = 0.048) or hypertension (0.34, p = 0.0089), and inhaled corticosteroid use in COPD subjects in bronchial biopsies (0.33, p = 0.049). Angiotensin II receptor type (AGTR)1 and 2 expression was decreased in COPD bronchial biopsies compared to HV-ES controls with log2FC of -0.26 (p = 0.033) and - 0.40, (p = 0.0010), respectively. However, the AGTR1:2 ratio was increased in COPD subjects compared with HV-ES controls, log2FC of 0.57 (p = 0.0051). Basigin, a newly identified potential SARS-CoV-2 receptor was also upregulated in both brushes, log2FC of 0.17 (p = 0.0040), and bronchial biopsies, (log2FC of 0.18 (p = 0.017), in COPD vs HV-ES. Transmembrane protease, serine (TMPRSS)2 was not differentially regulated between control and COPD. However, various other spike-cleaving proteases were, including TMPRSS4 and Cathepsin B, in both epithelial brushes (log2FC of 0.25 (p = 0.0012) and log2FC of 0.56 (p = 5.49E-06), respectively) and bronchial biopsies (log2FC of 0.49 (p = 0.00021) and log2FC of 0.246 (p = 0.028), respectively). CONCLUSION: This study identifies key differences in expression of genes related to susceptibility and aetiology of COVID-19 within the COPD lung. Further studies to understand the impact on clinical course of disease are now required.