Srage as biomarker for COPD, introducing novel LC-MS-based methods for the quantification of serum srage levels

Rationale: Soluble RAGE (sRAGE) is a promising biomarker for COPD and an attractive target for biomarker validation studies. Validated, reliable and clinically applicable biomarkers are needed for the early detection of COPD, identification of clinically relevant subgroups of COPD and for the selection of subjects for clinical trials. The circulating levels of sRAGE are decreased in COPD patients compared to both smoking and non-smoking controls, and are even further decreased during COPD exacerbations. Furthermore, the serum levels of sRAGE associate with neutrophilic airway inflammation, decline in FEV1, and emphysema. Methods: To date, most studies use commercially available ELISA kits for measurements of sRAGE, which have limited accuracy and reproducibility. Here, we present two novel liquid chromatography-mass spectrometry (LC-MS) methods for the quantification of sRAGE in serum. Our first approach measures the free, unbound fraction of sRAGE using an immunoaffinity enrichment-based method as sample preparation, comparable to the ELISA. Our second approach is an antibody-free method based on strong cation exchange solid-phase extraction, which likely measures the total sRAGE fraction. Both sample preparation methods are followed by LC-MS analysis in the multiple reaction monitoring mode. Results: Using the immunoaffinity enrichment-based method we are able to detect and quantify sRAGE in human serum over a large range (0.1-10 ng/mL) with high precision and accuracy (C

IL-33 expression is lower in current smokers at both transcriptomic and protein level

INTRODUCTION: IL-33 is a pro-inflammatory cytokine thought to play a role in the pathogenesis of asthma and COPD. A recent clinical trial using the anti-IL33 antibody showed a reduction in exacerbation and improved lung function in ex-smokers but not current smokers with COPD. In this study, we aimed to understand the effects of smoking status on IL-33. METHODS: We investigated the association of smoking status with the level of gene expression of IL33 in the airways in eight independent transcriptomic studies of lung airways. Additionally, we performed western blot and immunohistochemistry for IL-33 in lung tissue to assess protein levels. RESULTS: Across the bulk RNA-sequencing datasets, IL-33 gene expression and its signaling pathway were significantly lower in current- compared to ex- or never-smokers and increased upon smoking cessation (p<0.05). Single-cell sequencing showed that IL-33 is predominantly expressed in resting basal epithelial cells and decreases during the differentiation process triggered by smoke exposure. We also found a higher transitioning of this cellular sub-population into a more differentiated cell type during chronic smoking, potentially driving the reduction of IL-33. Protein analysis demonstrated lower IL-33 levels in lung tissue from COPD current- compared to ex-smokers and a lower proportion of IL-33 positive basal cells in current versus ex-smoking controls. CONCLUSION: We provide strong evidence that cigarette smoke leads to an overall reduction in IL33 expression in both transcriptomic and protein level and this may be due to the decrease in resting basal cells. Together, these findings may explain the clinical observation that a recent antibody-based anti-IL-33 treatment is more effective in ex- than current smokers with COPD

Precision medicine for more oxygen (P4O2): study design and first results of the Long COVID-19 extension

Introduction: The coronavirus disease 2019 (COVID-19) pandemic has led to the death of almost 7 million people, however, with a cumulative incidence of 0.76 billion, most people survive COVID-19. Several studies indicate that the acute phase of COVID-19 may be followed by persistent symptoms including fatigue, dyspnea, headache, musculoskeletal symptoms, and pulmonary functional-and radiological abnormalities. However, the impact of COVID-19 on long-term health outcomes remains to be elucidated. Aims: The Precision Medicine for more Oxygen (P4O2) consortium COVID-19 extension aims to identify long COVID patients that are at risk for developing chronic lung disease and furthermore, to identify treatable traits and innovative personalized therapeutic strategies for prevention and treatment. This study aims to describe the study design and first results of the P4O2 COVID-19 cohort. Methods: The P4O2 COVID-19 study is a prospective multicenter cohort study that includes nested personalized counseling intervention trial. Patients, aged 40-65 years, were recruited from outpatient post-COVID clinics from five hospitals in The Netherlands. During study visits at 3-6 and 12-18 months post-COVID-19, data from medical records, pulmonary function tests, chest computed tomography scans and biological samples were collected and questionnaires were administered. Furthermore, exposome data was collected at the patient's home and state-of-the-art imaging techniques as well as multi-omics analyses will be performed on collected data. Results: 95 long COVID patients were enrolled between May 2021 and September 2022. The current study showed persistence of clinical symptoms and signs of pulmonary function test/radiological abnormalities in post-COVID patients at 3-6 months post-COVID. The most commonly reported symptoms included respiratory symptoms (78.9%), neurological symptoms (68.4%) and fatigue (67.4%). Female sex and infection with the Delta, compared with the Beta, SARS-CoV-2 variant were significantly associated with more persisting symptom categories. Conclusions: The P4O2 COVID-19 study contributes to our understanding of the long-term health impacts of COVID-19. Furthermore, P4O2 COVID-19 can lead to the identification of different phenotypes of long COVID patients, for example those that are at risk for developing chronic lung disease. Understanding the mechanisms behind the different phenotypes and identifying these patients at an early stage can help to develop and optimize prevention and treatment strategies.Pathogenesis and treatment of chronic pulmonary disease