Andrew R L Medford

Differential expression of Toll-like receptor (TLR)-2 and TLR-4 on monocytes in human sepsis

Toll‐like receptors (TLRs) are a recently described family of immune receptors involved in the recognition of pathogen‐associated molecular patterns (PAMPs). The central role of TLR‐2 and TLR‐4 in microbial responses suggests they may be implicated in the pathogenesis of human sepsis. We hypothesized that the incidence and outcome of sepsis would be influenced by the expression of TLR‐2 and TLR‐4 on monocytes. We have examined the expression of TLR‐2 and TLR‐4 mRNA and protein and their response to pro‐ and anti‐inflammatory agents on monocytes from subjects in the intensive therapy unit (ITU) with and without Gram‐negative, Gram‐positive or polymicrobial sepsis. We compared these data to ITU and healthy control subjects. TLR‐2 mRNA was significantly up‐regulated on monocytes from subjects with both Gram‐positive and Gram‐negative sepsis. Similarly, we detected increased levels of TLR‐2 protein on the surface of monocytes from sepsis subjects relative to ITU controls. TLR‐4 mRNA was increased in Gram‐positive subjects; however, there was no corresponding increase in TLR‐4 protein. Although TLR‐4 mRNA expression in healthy control monocytes could be modulated in vitro by culture with lipopolysaccharide or interleukin‐10, this was not observed in monocytes obtained from sepsis and ITU control subjects, suggesting that septic and ITU control milieus may alter the immunoregulation of TLR‐4 mRNA expression on monocytes. TLR‐2 mRNA was not modulated in culture by any stimulus in any group. We suggest that expression and regulatory response of monocyte TLR‐2, and to a lesser extent TLR‐4 may be abnormal in human sepsis.

Predicting survival in malignant pleural effusion: development and validation of the LENT prognostic score

Background Malignant pleural effusion (MPE) causes debilitating breathlessness and predicting survival is challenging. This study aimed to obtain contemporary data on survival by underlying tumour type in patients with MPE, identify prognostic indicators of overall survival and develop and validate a prognostic scoring system. Methods Three large international cohorts of patients with MPE were used to calculate survival by cell type (univariable Cox model). The prognostic value of 14 predefined variables was evaluated in the most complete data set (multivariable Cox model). A clinical prognostic scoring system was then developed and validated. Results Based on the results of the international data and the multivariable survival analysis, the LENT prognostic score (pleural fluid lactate dehydrogenase, Eastern Cooperative Oncology Group (ECOG) performance score (PS), neutrophil-to-lymphocyte ratio and tumour type) was developed and subsequently validated using an independent data set. Risk stratifying patients into low-risk, moderate-risk and high-risk groups gave median (IQR) survivals of 319 days (228–549; n=43), 130 days (47–467; n=129) and 44 days (22–77; n=31), respectively. Only 65% (20/31) of patients with a high-risk LENT score survived 1 month from diagnosis and just 3% (1/31) survived 6 months. Analysis of the area under the receiver operating curve revealed the LENT score to be superior at predicting survival compared with ECOG PS at 1 month (0.77 vs 0.66, p<0.01), 3 months (0.84 vs 0.75, p<0.01) and 6 months (0.85 vs 0.76, p<0.01). Conclusions The LENT scoring system is the first validated prognostic score in MPE, which predicts survival with significantly better accuracy than ECOG PS alone. This may aid clinical decision making in this diverse patient population.

Vascular endothelial growth factor (VEGF) in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS): paradox or paradigm?

Acute respiratory distress syndrome (ARDS), the most severe form of acute lung injury (ALI), remains a devastating condition with a high mortality. It is characterised by alveolar injury and increased pulmonary vascular permeability. Vascular endothelial cell growth factor (VEGF) was identified by its properties to increase permeability and act as a cellular growth factor, hence its potential for a key role in the pathogenesis of ALI/ARDS. This review describes the basic biology of VEGF and its receptors as an essential prerequisite to discussing the available and sometimes paradoxical published data, before considering a paradigm for the role of VEGF in the human lung.

Vascular endothelial growth factor gene polymorphism and acute respiratory distress syndrome.

Background: Non-cardiogenic pulmonary oedema is a characteristic feature of the acute respiratory distress syndrome (ARDS). The properties of vascular endothelial growth factor (VEGF) as a potent vascular permogen and mitogen have led to investigation of its potential role in this condition. Lower VEGF plasma levels have been linked to the presence of the T allele in the +936 CT polymorphism. We hypothesised that the presence of the T allele would be associated with the development and severity of ARDS. Methods: A cohort of 137 normal subjects, 117 ventilated patients with ARDS, and 103 “at risk” of ARDS were genotyped for the VEGF+936 CT polymorphism. The severity of physiological disturbance and mortality was determined in the ventilated cohorts. Results: The CT and TT genotype frequencies were increased in ARDS patients compared with both normal subjects (OR 2.01, 95% CI 1.13 to 3.58, p = 0.02) and those “at risk” (OR 2.05, 95% CI 1.02 to 2.20, p = 0.03). In patients with ARDS but not those “at risk”, CT and TT genotypes were associated with a higher mean APACHE III score (80.9 (4.3) v 69.3 (2.9), p<0.05). Conclusion: These data support a role for VEGF in the pathogenesis of ARDS and its associated physiological derangement.

Mediastinal staging procedures in lung cancer: EBUS, TBNA and mediastinoscopy

Purpose of review There is increasing awareness of minimally invasive endoscopic techniques for mediastinal staging in lung cancer. Traditionally, cervical mediastinoscopy has been utilized. Endobronchial ultrasound-guided fine needle aspiration (EBUS) has recently emerged as a potential alternative. Recent findings EBUS has sensitivity for lung cancer which is at least equivalent (if not superior) to cervical mediastinoscopy. However, cervical mediastinoscopy remains superior to EBUS and other techniques in its high negative predictive value. More recent data suggest EBUS may have a role in presurgical staging of radiologically normal subcentimetre nodes and its negative predictive value may be equivalent to surgical staging. Ongoing comparative studies between EBUS and cervical mediastinoscopy may well clarify relative performance and cost analyses. Summary Currently, insufficient data are present to recommend replacing cervical mediastinoscopy with EBUS for lung cancer staging; the negative predictive value of EBUS requires validation. However, EBUS can be recommended for initial staging as a minimally invasive option provided negative results are followed by cervical mediastinoscopy. This would also allow cervical mediastinoscopy to be reserved for re-staging. Conventional transbronchial needle aspiration has a limited role only as a first-line staging procedure but may aid diagnosis. In the future, EBUS may have a role in presurgical staging of the radiologically normal mediastinum and re-staging if prior staging is done by cervical mediastinoscopy.

A performance and theoretical cost analysis of endobronchial ultrasound-guided transbronchial needle aspiration in a UK tertiary respiratory centre

BACKGROUND New innovative techniques can improve patient care but may not be appropriately funded. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS) offers a minimally invasive mediastinal staging and diagnostic method for suspected lung cancer. AIM We report the performance and cost analysis of a newly established EBUS service in a prospective real world cohort of patients to assess the impact of Payment by Results (PbR). DESIGN Prospective cohort study. METHODS Fifty-four patients between June 2008 and April 2009 underwent EBUS for evaluation of unexplained mediastinal lymphadenopathy on CT. Cost analysis was performed from local Trust financial data and 2008-09 tariffs. RESULTS EBUS had an 89% sensitivity, 75% negative predictive value and 92% accuracy for malignancy. EBUS coding was inaccurate in 15.6% of cases. The actual cost of an EBUS is 1252-1433 pounds but is coded as a standard bronchoscopy (561 pounds). EBUS reduces health community costs by 107824 pounds/year, as a result of a Primary Care Trust cost saving of 113968 pounds/year and a Trust cost deficit of 6144 pounds/year. Coding inaccuracies further alter the Primary Care Trust costs. CONCLUSION Medical innovation is fundamental to improved patient care. EBUS can potentially reduce morbidity for lung cancer patients and save health community costs. However, with PbR the service provider delivers this at a loss as the tariffs do not reflect innovation and because of coding inaccuracies. We suggest tariffs for innovative procedures need to reflect the true cost.

A Prospective Study of Conventional Transbronchial Needle Aspiration: Performance and Cost Utility

Background: Conventional transbronchial needle aspiration (TBNA) is a cheap, minimally invasive tool for lung cancer staging and diagnosis. Endobronchial ultrasound-guided TBNA (EBUS-TBNA) is more sensitive but is more expensive and less widely available. We describe a prospective analysis of TBNA diagnostic, staging and cost utility in a centre in the UK. Objectives: To illustrate the potential diagnostic, staging and cost utility of a low cost conventional TBNA service. Methods: A prospective analysis of 79 TBNA procedures over a 2-year period was performed looking at performance and cost utility in a ‘mixed’ cohort with variable pre-test probability of malignancy (year 1) followed by a high probability cohort (year 2). Results: TBNA avoided mediastinoscopy in 25% of the cases overall (37% in high probability vs. 13% in the ‘mixed’ cohort, p = 0.03). The overall prevalence of malignancy was 84%, sensitivity 79%, negative predictive value 58% and accuracy 85%. Diagnostic utility varied with pre-test probability and nodal station. TBNA down-staged 8% of lung cancer patients to receive surgery and confirmed the pre-treatment stage (inoperability) in 74%. TBNA led to theoretical cost savings of GBP 560 per patient. Conclusions: TBNA can achieve a high diagnostic sensitivity for cancer in high probability patients and stage the majority appropriately, thereby avoiding unnecessary mediastinoscopies and reducing costs. It may also down-stage a minority to have surgery. TBNA is cheap, routinely available and learnable. As EBUS-TBNA will take time to develop due to its costs, all respiratory centres should perform TBNA at flexible bronchoscopy in suspected lung cancer with accessible mediastinal adenopathy.

Vascular Endothelial Growth Factor (VEGF) isoform expression and activity in human and murine lung injury

BackgroundThe properties of vascular endothelial growth factor (VEGF) as a potent vascular permogen and mitogen have led to investigation of its potential role in lung injury. Alternate spliced VEGF transcript generates several isoforms with potentially differing functions. The purpose of this study was to determine VEGF isoform expression and source in normal and ARDS subjects and investigate the expression and regulation of VEGF isoforms by human alveolar type 2 (ATII) cells.MethodsVEGF protein expression was assessed immunohistochemically in archival normal and ARDS human lung tissue. VEGF isoform mRNA expression was assessed in human and murine lung tissue. Purified ATII cells were cultured with proinflammatory cytokines prior to RNA extraction/cell supernatant sampling/proliferation assay.Measurements and Main ResultsVEGF was expressed on alveolar epithelium, vascular endothelium and alveolar macrophages in normal and ARDS human lung tissue. Increases in VEGF expression were detected in later ARDS in comparison to both normal subjects and early ARDS (p < 0.001). VEGF121, VEGF165 and VEGF189 isoform mRNA expression increased in later ARDS (p < 0.05). The ratio of soluble to cell-associated isoforms was lower in early ARDS than normal subjects and later ARDS and also in murine lung injury. ATII cells constitutionally produced VEGF165 and VEGF121 protein which was increased by LPS (p < 0.05). VEGF165 upregulated ATII cell proliferation (p < 0.001) that was inhibited by soluble VEGF receptor 1 (sflt) (p < 0.05).ConclusionThese data demonstrate that changes in VEGF isoform expression occur in ARDS which may be related to their production by and mitogenic effect on ATII cells; with potentially significant clinical consequences.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA): Applications in chest disease

Endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA) offers a minimally invasive option for staging the mediastinum in suspect lung cancer but also in the diagnosis of mediastinal lesions accessible from the airway. This review is aimed at centres considering establishing an EBUS service that may not be so familiar with the technique. It focuses primarily on technical aspects of EBUS‐TBNA, training issues, cost considerations, indications, advantages and disadvantages compared with other mediastinal sampling techniques as well as some reference to its performance in clinical studies.

Impact of needle gauge on characterization of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) histology samples.

Endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA) is a minimally invasive mediastinal node sampling technique used for lung cancer staging and diagnosis of mediastinal lesions. The four published studies assessing sampling with 21‐G or 22‐G needles conflict. The study objective is to evaluate the diagnostic utility of 21‐G versus 22‐G EBUS‐TBNA needles, and the ability to subcharacterize both benign and malignant lesions using histopathological assessment only.