Rituximab in autoimmune connective tissue disease–associated interstitial lung disease

Objective. CTD-associated interstitial lung disease (ILD) often fails to respond to conventional immunomodulatory agents. There is now considerable interest in the use of rituximab in systemic autoimmune CTD in patients refractory to standard treatments. The aim of this study was to review the experience of North Bristol NHS Trust managing patients with CTD-associated ILD with rituximab and explore possible associations with treatment response. Methods. We conducted a retrospective analysis of all patients who received rituximab under the Bristol CTD-ILD service, having failed to respond to other immunomodulatory treatments. Results were collated for pulmonary function and radiological outcomes before and after treatment. Results. Twenty-four patients were treated with rituximab. Their physiological parameters had failed to improve despite other immunomodulatory agents, with a mean change in forced vital capacity (FVC) prior to therapy of − 3.3% (95% CI − 5.6, −1.1) and mean change in diffusing capacity of carbon monoxide of − 4.3% (95% CI − 7.7, −0.9). After rituximab, radiology remained stable or improved for 11 patients, while worsening was observed in 9 patients. The decline in FVC was halted following treatment, with a mean change of + 4.1% (95% CI 0.9, 7.2), while diffusing capacity of carbon monoxide was stable [mean change +2.1% (95% CI − 1.0, 5.2)]. Patients with myositis overlap or antisynthetase syndrome appeared to respond well to treatment, with four patients showing clinically significant improvement in FVC >10%. Conclusion. Rituximab is a therapeutic option in treatment-refractory CTD-associated ILD. Some disease subgroups may respond better than others, however, more work is needed to define its role in managing these patients

VEGF (Vascular Endothelial Growth Factor) and Fibrotic Lung Disease

Interstitial lung disease (ILD) encompasses a group of heterogeneous diseases characterised by varying degrees of aberrant inflammation and fibrosis of the lung parenchyma. This may occur in isolation, such as in idiopathic pulmonary fibrosis (IPF) or as part of a wider disease process affecting multiple organs, such as in systemic sclerosis. Anti-Vascular Endothelial Growth Factor (anti-VEGF) therapy is one component of an existing broad-spectrum therapeutic option in IPF (nintedanib) and may become part of the emerging therapeutic strategy for other ILDs in the future. This article describes our current understanding of VEGF biology in normal lung homeostasis and how changes in its bioavailability may contribute the pathogenesis of ILD. The complexity of VEGF biology is particularly highlighted with an emphasis on the potential non-vascular, non-angiogenic roles for VEGF in the lung, in both health and disease

Epidemiological study of E. coli O157:H7 isolated in Northern Ireland using pulsed-field gel electrophoresis (PFGE)

In Northern Ireland over the last 7 years, there is a mean of 41.9 laboratory reports per annum of human gastrointestinal infection (range 19-54) caused by Escherichia coli O157:H7. In the preceding years 1992-1996, reports were 5.4 per annum, whereas in 1997-2000, reports increased from 30 to 54 per annum. This high level has continued on an annual basis to date. The aim of this study was therefore to retrospectively examine this period of exponential increase in reports to help ascertain the genetic relatedness of strains employing pulsed-field gel electrophoresis (PFGE), as no data on the molecular epidemiology of E. coli O157:H7 in Northern Ireland has yet been published. Clinical isolates (n=84) were PFGE typed employing Xba I digestion and resulting band profiles demonstrated the presence of 13, 9 and 16 clonal types, for 1997, 1998 and 1999, respectively. In 1998, five clonal types remained from 1997 with the introduction of 4 new clonal types, whereas in 1999, 10 new clonal types were observed, accounting for over half (58%) of the E. coli O157 isolates for that year. These data suggest that, unlike gastrointestinal infections due to thermophilic campylobacters, there was considerable genetic evolution of PFGE clonal types of E. coli O157, through the displacement and emergence of genotypes. Further studies are now required to find the environmental reservoirs of these common clonal types of clinical E. coli O157:H7 in Northern Ireland to help define sources and routes of transmission of this infection locally

VEGF isoforms have differential effects on permeability of human pulmonary microvascular endothelial cells

Abstract Background Alternative splicing of Vascular endothelial growth factor-A mRNA transcripts (commonly referred as VEGF) leads to the generation of functionally differing isoforms, the relative amounts of which have potentially significant physiological outcomes in conditions such as acute respiratory distress syndrome (ARDS). The effect of such isoforms on pulmonary vascular permeability is unknown. We hypothesised that VEGF165a and VEGF165b isoforms would have differing effects on pulmonary vascular permeability caused by differential activation of intercellular signal transduction pathways. Method To test this hypothesis we investigated the physiological effect of VEGF165a and VEGF165b on Human Pulmonary Microvascular Endothelial Cell (HPMEC) permeability using three different methods: trans-endothelial electrical resistance (TEER), Electric cell-substrate impedance sensing (ECIS) and FITC-BSA passage. In addition, potential downstream signalling pathways of the VEGF isoforms were investigated by Western blotting and the use of specific signalling inhibitors. Results VEGF165a increased HPMEC permeability using all three methods (paracellular and transcellular) and led to associated VE-cadherin and actin stress fibre changes. In contrast, VEGF165b decreased paracellular permeability and did not induce changes in VE-cadherin cell distribution. Furthermore, VEGF165a and VEGF165b had differing effects on both the phosphorylation of VEGF receptors and downstream signalling proteins pMEK, p42/44MAPK, p38 MAPK, pAKT and peNOS. Interestingly specific inhibition of the pMEK, p38 MAPK, PI3 kinase and eNOS pathways blocked the effects of both VEGF165a and VEGF165b on paracellular permeability and the effect of VEGF165a on proliferation/migration, suggesting that this difference in cellular response is mediated by an as yet unidentified signalling pathway(s). Conclusion This study demonstrates that the novel isoform VEGF165a and VEGF165b induce differing effects on permeability in pulmonary microvascular endothelial cells

The role of IREB2 and transforming growth factor beta-1 genetic variants in COPD: a replication case-control study

<p>Abstract</p> <p>Background</p> <p>Genetic factors are known to contribute to COPD susceptibility and these factors are not fully understood. Conflicting results have been reported for many genetic studies of candidate genes based on their role in the disease. Genome-wide association studies in combination with expression profiling have identified a number of new candidates including <it>IREB2</it>. A meta-analysis has implicated transforming growth factor beta-1 (<it>TGFbeta1</it>) as a contributor to disease susceptibility.</p> <p>Methods</p> <p>We have examined previously reported associations in both genes in a collection of 1017 white COPD patients and 912 non-diseased smoking controls. Genotype information was obtained for seven SNPs in the <it>IREB2 </it>gene, and for four SNPs in the <it>TGFbeta1 </it>gene. Allele and genotype frequencies were compared between COPD cases and controls, and odds ratios were calculated. The analysis was adjusted for age, sex, smoking and centre, including interactions of age, sex and smoking with centre.</p> <p>Results</p> <p>Our data replicate the association of <it>IREB2 </it>SNPs in association with COPD for SNP rs2568494, rs2656069 and rs12593229 with respective adjusted p-values of 0.0018, 0.0039 and 0.0053. No significant associations were identified for <it>TGFbeta1</it>.</p> <p>Conclusions</p> <p>These studies have therefore confirmed that the <it>IREB2 </it>locus is a contributor to COPD susceptibility and suggests a new pathway in COPD pathogenesis invoking iron homeostasis.</p

Differential expression of VEGF-Axxx isoforms is critical for development of pulmonary fibrosis

RATIONALE Fibrosis after lung injury is related to poor outcome, and idiopathic pulmonary fibrosis (IPF) can be regarded as an exemplar. Vascular endothelial growth factor (VEGF)-A has been implicated in this context, but there are conflicting reports as to whether it is a contributory or protective factor. Differential splicing of the VEGF-A gene produces multiple functional isoforms including VEGF-Aa and VEGF-Ab, a member of the inhibitory family. To date there is no clear information on the role of VEGF-A in IPF. OBJECTIVES To establish VEGF-A isoform expression and functional effects in IPF. METHODS We used tissue sections, plasma, and lung fibroblasts from patients with IPF and control subjects. In a bleomycin-induced lung fibrosis model we used wild-type MMTV mice and a triple transgenic mouse SPC-rtTATetoCreLoxP-VEGF-Ato conditionally induce VEGF-A isoform deletion specifically in the alveolar type II (ATII) cells of adult mice. MEASUREMENTS AND MAIN RESULTS IPF and normal lung fibroblasts differentially expressed and responded to VEGF-Aa and VEGF-Ab in terms of proliferation and matrix expression. Increased VEGF-Ab was detected in plasma of progressing patients with IPF. In a mouse model of pulmonary fibrosis, ATII-specific deficiency of VEGF-A or constitutive overexpression of VEGF-Ab inhibited the development of pulmonary fibrosis, as did treatment with intraperitoneal delivery of VEGF-Ab to wild-type mice. CONCLUSIONS These results indicate that changes in the bioavailability of VEGF-A sourced from ATII cells, namely the ratio of VEGF-Aa to VEGF-Ab, are critical in development of pulmonary fibrosis and may be a paradigm for the regulation of tissue repair

The role of microRNA-155/liver X receptor pathway in experimental and idiopathic pulmonary fibrosis

Background: Idiopathic Pulmonary Fibrosis (IPF) is progressive and rapidly fatal. Improved understanding of pathogenesis is required to prosper novel therapeutics. Epigenetic changes contribute to IPF therefore microRNAs may reveal novel pathogenic pathways. Objectives: To determine the regulatory role of microRNA(miR)-155 in the pro-fibrotic function of murine lung macrophages and fibroblasts, IPF lung fibroblasts and its contribution to experimental pulmonary fibrosis. Methods: Bleomycin-induced lung fibrosis in wild-type and miR-155-/- mice was analyzed by histology, collagen and pro-fibrotic gene expression. Mechanisms were identified by in silico and molecular approaches; validated in mouse lung fibroblasts and macrophages, and in IPF lung fibroblasts, using loss-and-gain of function assays, and in vivo using specific inhibitors. Results: miR-155-/- mice developed exacerbated lung fibrosis, increased collagen deposition, collagen 1 and 3 mRNA expression, TGFβ production, and activation of alternatively-activated macrophages, contributed by deregulation of the microRNA-155 target gene the liver X receptor (LXR)α in lung fibroblasts and macrophages. Inhibition of LXRα in experimental lung fibrosis and in IPF lung fibroblasts reduced the exacerbated fibrotic response. Similarly, enforced expression of miR-155 reduced the pro-fibrotic phenotype of IPF and miR-155-/- fibroblasts. Conclusion: We describe herein a molecular pathway comprising miR-155 and its epigenetic LXRα target that when deregulated enables pathogenic pulmonary fibrosis. Manipulation of the miR-155/LXR pathway may have therapeutic potential for IPF