A Pilot Feasibility Study in Establishing the Role of Ultrasound-Guided Pleural Biopsies in Pleural Infection (The AUDIO Study)

Background Pleural infection is a common complication of pneumonia associated with high mortality and poor clinical outcome. Treatment of pleural infection relies on the use of broad-spectrum antibiotics because reliable pathogen identification occurs infrequently. We performed a feasibility interventional clinical study assessing the safety and significance of ultrasound (US)-guided pleural biopsy culture to increase microbiological yield. In an exploratory investigation, the 16S ribosomal RNA technique was applied to assess its utility on increasing speed and accuracy vs standard microbiological diagnosis. Methods Twenty patients with clinically established pleural infection were recruited. Participants underwent a detailed US scan and US-guided pleural biopsies before chest drain insertion, alongside standard clinical management. Pleural biopsies and routine clinical samples (pleural fluid and blood) were submitted for microbiological analysis. Results US-guided pleural biopsies were safe with no adverse events. US-guided pleural biopsies increased microbiological yield by 25% in addition to pleural fluid and blood samples. The technique provided a substantially higher microbiological yield compared with pleural fluid and blood culture samples (45% compared with 20% and 10%, respectively). The 16S ribosomal RNA technique was successfully applied to pleural biopsy samples, demonstrating high sensitivity (93%) and specificity (89.5%). Conclusions Our findings demonstrate the safety of US-guided pleural biopsies in patients with pleural infection and a substantial increase in microbiological diagnosis, suggesting potential niche of infection in this disease. Quantitative polymerase chain reaction primer assessment of pleural fluid and biopsy appears to have excellent sensitivity and specificity.</p

Mutant KRAS promotes malignant pleural effusion formation

Malignant pleural effusion (MPE) is the lethal consequence of various human cancers metastatic to the pleural cavity. However, the mechanisms responsible for the development of MPE are still obscure. Here we show that mutant KRAS is important for MPE induction in mice. Pleural disseminated, mutant KRAS bearing tumour cells upregulate and systemically release chemokine ligand 2 (CCL2) into the bloodstream to mobilize myeloid cells from the host bone marrow to the pleural space via the spleen. These cells promote MPE formation, as indicated by splenectomy and splenocyte restoration experiments. In addition, KRAS mutations are frequently detected in human MPE and cell lines isolated thereof, but are often lost during automated analyses, as indicated by manual versus automated examination of Sanger sequencing traces. Finally, the novel KRAS inhibitor deltarasin and a monoclonal antibody directed against CCL2 are equally effective against an experimental mouse model of MPE, a result that holds promise for future efficient therapies against the human condition

Whole transcriptome data analysis of mouse embryonic hematopoietic stem and progenitor cells that lack Geminin expression

We performed cDNA microarrays (Affymetrix Mouse Gene 1.0 ST Chip) to analyze the transcriptome of hematopoietic stem and progenitor cells (HSPCs) from E15.5dpc wild type and Geminin (Gmnn) knockout embryos. Lineage negative cells from embryonic livers were isolated using fluorescence activated cell sorting. RNA samples were used to examine the transcriptional programs regulated by Geminin during embryonic hematopoiesis. The data sets were analyzed using the GeneSpring v12.5 platform (Agilent). The list of differentially expressed genes was filtered in meta-analyses to investigate the molecular basis of the phenotype observed in the knockout embryos, which exhibited defective hematopoiesis and death. The data from this study are related to the research article “Geminin deletion increases the number of fetal hematopoietic stem cells by affecting the expression of key transcription factors” (Karamitros et al., 2015) [1].The microarray dataset has been deposited at the Gene Expression Omnibus (GEO) under accession GEO: GSE53056

The association between pleural fluid exposure and survival in pleural mesothelioma

Background: Most patients with malignant pleural mesothelioma (MPM) present with malignant pleural effusion (MPE). There is in vitro evidence that MPE may not be a simple bystander of malignancy, but potentially has biological properties improving cancer cell survival and promoting cancer progression. If this is the case, MPE management may need to shift from current symptomatic strategies to aggressive fluid removal to impact on survival. Research question: Is there an association between pleural fluid exposure and survival in MPM? Study design and Methods: Data on 761 patients diagnosed with MPM between 2008-2018 were collected from patient medical records in 3 UK pleural units. Data included factors previously identified as influencing prognosis in MPM. Medical imaging was reviewed for presence, size and duration of pleural effusion. Time-dependent covariate analysis of pleural fluid exposure and survival (model included weight loss, serum albumin, Hb, MPM subtype, performance status, chemotherapy, age), and multivariable cox regression analysis of pleurodesis and survival were conducted. Results: Median overall survival was 278 days (IQR 127-505, 95% CI 253-301). Pleural fluid exposure duration showed no association with survival (HR 1.0, 95% CI 1.0-1.0). Median survival was 473, 378 and 258 days with complete, partial, and no pleurodesis (p 0.008). Interpretation: Pleurodesis success appears to be associated with improved survival, however it is unclear whether duration of MPM exposure to pleural fluid is associated with survival within the limitations of this retrospective study. Future prospective studies are required to assess this potentially important mechanism

Intercostal vessel screening prior to pleural interventions by the respiratory physician: a prospective study of real world practice

Introduction The rising incidence of pleural disease is seeing an international growth of pleural services, with physicians performing an ever-increasing volume of pleural interventions. These are frequently conducted at sites without immediate access to thoracic surgery or interventional radiology and serious complications such as pleural bleeding are likely to be under-reported. Aim To assess whether intercostal vessel screening can be performed by respiratory physicians at the time of pleural intervention, as an additional step that could potentially enhance safe practice. Methods This was a prospective, observational study of 596 ultrasound-guided pleural procedures conducted by respiratory physicians and trainees in a tertiary centre. Operators did not have additional formal radiology training. Intercostal vessel screening was performed using a low frequency probe and the colour Doppler feature. Results The intercostal vessels were screened in 95% of procedures and the intercostal artery (ICA) was successfully identified in 53% of cases. Screening resulted in an overall site alteration rate of 16% in all procedures, which increased to 30% when the ICA was successfully identified. This resulted in procedure abandonment in 2% of cases due to absence of a suitable entry site. Intercostal vessel screening was shown to be of particular value in the context of image-guided pleural biopsy. Conclusion Intercostal vessel screening is a simple and potentially important additional step that can be performed by respiratory physicians at the time of pleural intervention without advanced ultrasound expertise. Whether the widespread use of this technique can improve safety requires further evaluation in a multi-centre setting with a robust prospective study

Pleural fluid has pro-growth biological properties which enable cancer cell proliferation

Objectives: Patients with malignant pleural mesothelioma (MPM) or pleural metastases often present with malignant pleural effusion (MPE). This study aimed to analyse the effect of pleural fluid on cancer cells. Materials and Methods: Established patient-derived cancer cell cultures derived from MPE (MPM, breast carcinoma, lung adenocarcinoma) were seeded in 100% pleural fluid (exudate MPM MPE, transudate MPE, non-MPE transudate fluid) and proliferation was monitored. In addition, the establishment of new MPM cell cultures, derived from MPE specimens, was attempted by seeding the cells in 100% MPE fluid. Results: All established cancer cell cultures proliferated with similar growth rates in the different types of pleural fluid. Primary MPM cell culture success was similar with MPE fluid as with full culture medium. Conclusions: Pleural fluid alone is adequate for cancer cell proliferation in vitro, regardless of the source of pleural fluid. These results support the hypothesis that pleural fluid has important pro-growth biological properties, but the mechanisms for this effect are unclear and likely not malignant effusion specific.peer-reviewe