M. Musk

Macitentan for the treatment of idiopathic pulmonary fibrosis: the randomised controlled MUSIC trial

Idiopathic pulmonary fibrosis is a progressive, fatal disease. This prospective, randomised, double-blind, multicentre, parallel-group, placebo-controlled phase II trial (NCT00903331) investigated the efficacy and safety of the endothelin receptor antagonist macitentan in idiopathic pulmonary fibrosis. Eligible subjects were adults with idiopathic pulmonary fibrosis of <3 years duration and a histological pattern of usual interstitial pneumonia on surgical lung biopsy. The primary objective was to demonstrate that macitentan (10 mg once daily) positively affected forced vital capacity versus placebo. Using a centralised system, 178 subjects were randomised (2:1) to macitentan (n=119) or placebo (n=59). The median change from baseline up to month 12 in forced vital capacity was -0.20 L in the macitentan arm and -0.20 L in the placebo arm. Overall, no differences between treatments were observed in pulmonary function tests or time to disease worsening or death. Median exposures to macitentan and placebo were 14.5 months and 15.0 months, respectively. Alanine and/or aspartate aminotransferase elevations over three times upper limit of normal arose in 3.4% of macitentan-treated subjects and 5.1% of placebo recipients. In conclusion, the primary objective was not met. Long-term exposure to macitentan was well tolerated with a similar, low incidence of elevated hepatic aminotransferases in each treatment group. Long-term exposure to macitentan was well tolerated in IPF in a trial that did not meet its primary end-point http://ow.ly/p0RDL

Human Metapneumovirus in Lung Transplant Recipients and Comparison to Respiratory Syncytial Virus

RATIONALE Human metapneumovirus is a newly described virus isolated in 2001 from children with acute respiratory viral infection. It has subsequently been reported globally, although there are limited data in lung transplant recipients. OBJECTIVES To prospectively analyze whether human metapneumovirus was circulating in our adult lung transplant community and assess the morbidity of this infection and to compare the clinical presentation and outcome after intravenous ribavirin of human metapneumovirus with that of respiratory syncytial virus (RSV). METHODS Lung transplant patients with clinical features of respiratory viral infection underwent nasopharyngeal aspirates. Patients with a positive specimen for RSV or human metapneumovirus by reverse transcriptase-polymerase chain reaction analysis and graft dysfunction received intravenous ribavirin and pulse steroid therapy. MEASUREMENTS AND MAIN RESULTS Eighty-nine patients had 199 visits for aspirate studies. A viral cause was determined for 62 visits in 47 patients (19 human metapneumovirus, 18 RSV, 13 parainfluenza, 9 influenza A, 2 adenovirus, and 1 influenza B). A significant percentage of patients with metapneumovirus (63%) and RSV (72%) developed graft dysfunction, with average declines in FEV(1) of 30 +/- 12.4% and 25.9 +/- 11.2%, respectively. In these patients, bronchiolitis obliterans syndrome onset or progression occurred in no patients with human metapneumovirus compared with 5 of 13 (38%) patients with RSV at 6 months. CONCLUSIONS Human metapneumovirus is a leading cause of acute respiratory tract illness in lung transplant recipients. The incidence and clinical spectrum at presentation are similar to RSV, although the latter seems to be associated with a higher risk of chronic rejection. We recommend testing of nasopharyngeal aspirates for human metapneumovirus with polymerase chain reaction to assess local epidemiologic patterns.

Prevalence of pulmonary arterial hypertension in an Australian scleroderma population: screening allows for earlier diagnosis

Background:  We sought to determine the prevalence of pulmonary complications and especially pulmonary arterial hypertension (PAH) in an Australian scleroderma population.

Posttransplant Bronchiolitis Obliterans Syndrome Is Associated with Bronchial Epithelial to Mesenchymal Transition

Bronchiolitis obliterans syndrome (BOS) compromises lung transplant outcomes and is characterised by airway epithelial damage and fibrosis. The process whereby the normal epithelial configuration is replaced by fibroblastic scar tissue is poorly understood, but recent studies have implicated epithelial mesenchymal transition (EMT). The primary aim of this study was to assess the utility of flow cytometry in detecting and quantifying EMT in bronchial epithelial cells.

The Impact of Pandemic Influenza A H1N1 2009 on Australian Lung Transplant Recipients

Influenza A H1N1 2009 led to 189 deaths during the Australian pandemic. Community‐acquired respiratory viruses not only can cause prolonged allograft dysfunction in lung transplant recipients but have also been linked to bronchiolitis obliterans syndrome (BOS). We report the impact of the 2009 H1N1 pandemic on Australian lung transplant recipients. An observational study of confirmed H1N1 cases was conducted across five Australian lung transplant programs during the pandemic. An electronic database collected patient demographics, clinical presentation, management and outcomes up to a year follow‐up. Twenty‐four H1N1 cases (mean age 43 ± 14 years, eight females) were identified, incidence of 3%. Illness severity varied from upper respiratory tract symptoms only in 29% to lung allograft dysfunction (≥10% decline FEV1) in 75% to death in 5 (21%) cases (pre‐existing BOS grade 3, n = 4). Treatment with oseltamivir occurred in all but one case confirmed after death, reduced immunosuppression, n = 1, augmented corticosteroid therapy, n = 16, and mechanical/noninvasive ventilation, n = 4. There was BOS grade decline within a year in six cases (32%). In conclusion, Australian lung transplant recipients were variably affected by the H1N1 pandemic mirroring the broader community with significant morbidity and mortality. After initial recovery, a considerable proportion of survivors have demonstrated BOS progression.

Successful establishment of primary small airway cell cultures in human lung transplantation

BackgroundThe study of small airway diseases such as post-transplant bronchiolitis obliterans syndrome (BOS) is hampered by the difficulty in assessing peripheral airway function either physiologically or directly. Our aims were to develop robust methods for sampling small airway epithelial cells (SAEC) and to establish submerged SAEC cultures for downstream experimentation.MethodsSAEC were obtained at 62 post-transplant bronchoscopies in 26 patients using radiologically guided bronchial brushings. Submerged cell cultures were established and SAEC lineage was confirmed using expression of clara cell secretory protein (CCSP).ResultsThe cell yield for SAEC (0.956 ± 0.063 × 106) was lower than for large airway cells (1.306 ± 0.077 × 106) but did not significantly impact on the culture establishment rate (79.0 ± 5.2% vs. 83.8 ± 4.7% p = 0.49). The presence of BOS significantly compromised culture success (independent of cell yield) for SAEC (odds ratio (95%CI) 0.067 (0.01-0.40)) but not LAEC (0.3 (0.05-1.9)). Established cultures were successfully passaged and expanded.ConclusionPrimary SAEC can be successfully obtained from human lung transplant recipients and maintained in culture for downstream experimentation. This technique will facilitate the development of primary in vitro models for BOS and other diseases with a small airway component such as asthma, cystic fibrosis and COPD.

The airway epithelium is a direct source of matrix degrading enzymes in bronchiolitis obliterans syndrome

BACKGROUND Long-term survival after lung transplantation is hindered by the development of bronchiolitis obliterans syndrome (BOS), and recent evidence suggests that dysregulated epithelial repair may underlie its development. Because matrix metalloproteinase (MMP) -2 and MMP-9 secretion is integral to repair, we hypothesized that airway epithelial cells from patients with BOS would over-express these matrix-degrading enzymes. METHODS Cells obtained from bronchial and bronchiolar brushings from patients with and without BOS (without acute rejection or infection) were analyzed via quantitative polymerase chain reaction and immunocytochemistry for MMP-2, and MMP-9 gene and protein expression. The expression of tissue inhibitor of metalloproteinase (TIMP)2 and TIMP1 was also assessed. MMP activity in bronchoalveolar lavage was determined via gelatin zymography. RESULTS MMP-2 and MMP-9 production was significantly higher in bronchoalveolar lavage (3.85- and 11.59-fold, p < 0.001) and airway epithelium (MMP-2 bronchial: 6.33-fold, bronchiolar: 3.57-fold, both p < 0.001; MMP-9 bronchial: 32.55-fold, p < 0.001; bronchiolar: 8.60-fold, p = 0.01) in patients with BOS, but expression in patients without BOS was not different from healthy controls. TIMP expression was similar in patients with and without BOS. Immunostaining confirmed that the airway epithelium was a direct source of MMP-2 and MMP-9 expression in patients with BOS. CONCLUSION In patients with BOS, the airway epithelium over-expresses MMPs, even in the absence of acute rejection or infection. Dysregulated epithelial repair may be a key feature of BOS.

Pulmonary hypertension in pregnancy: two cases and review of the literature

Pulmonary arterial hypertension (PAH) in pregnancy carries a mortality of 30–56%. There are few published data to guide clinicians in its management. Two pregnant women with severe PAH have been treated at Royal Perth Hospital with a successful result in both. Their presentation and management are described. We review the physiological changes in pregnancy, pathophysiology in PAH, and review the literature describing treatment of PAH in pregnancy.

Regional Differences in Susceptibiity of Bronchial Epithelium to Mesenchymal Transition and Inhibition by the Macrolide Antibiotic Azithromycin

Objective Dysregulated repair following epithelial injury is a key forerunner of disease in many organs, and the acquisition of a mesenchymal phenotype by the injured epithelial cells (epithelial to mesenchymal transition, EMT) may serve as a source of fibrosis. The macrolide antibiotic azithromycin and the DNA synthesis inhibitor mycophenolate are in clinical use but their mechanism of action remains unknown in post-transplant bronchiolitis obliterans syndrome (BOS). Here we determined if regional variation in the EMT response to TGFβ1 underlies the bronchiolocentric fibrosis leading to BOS and whether EMT could be inhibited by azithromycin or mycophenolate. Methods/Results We found that small and large airway epithelial cells from stable lung transplant patients underwent EMT when stimulated with TGFβ1, however mesenchymal protein expression was higher and loss of epithelial protein expression more complete in small airway epithelial cells. This regional difference was not mediated by changes in expression of the TGFβRII or Smad3 activation. Azithromycin potentially inhibited EMT in both small and large airway epithelial cells by inhibiting Smad3 expression, but not activation. Conclusion Collectively, these observations provide a biologic basis for a previously unexplained but widely observed clinical phenomena, and a platform for the development of new approaches to fibrotic diseases.

Mesenchymal Stromal Cell Therapy for Chronic Lung Allograft Dysfunction: Results of a First‐in‐Man Study

Chronic lung transplant rejection (termed chronic lung allograft dysfunction [CLAD]) is the main impediment to long‐term survival after lung transplantation. Bone marrow‐derived mesenchymal stromal cells (MSCs) represent an attractive cell therapy in inflammatory diseases, including organ rejection, given their relative immune privilege and immunosuppressive and tolerogenic properties. Preclinical studies in models of obliterative bronchiolitis and human trials in graft versus host disease and renal transplantation suggest potential efficacy in CLAD. The purpose of this phase 1, single‐arm study was to explore the feasibility and safety of intravenous delivery of allogeneic MSCs to patients with advanced CLAD. MSCs from unrelated donors were isolated from bone marrow, expanded and cryopreserved in a GMP‐compliant facility. Patients had deteriorating CLAD and were bronchiolitis obliterans (BOS) grade ≥ 2 or grade 1 with risk factors for rapid progression. MSCs (2 x 106 cells per kilogram patient weight) were infused via a peripheral vein twice weekly for 2 weeks, with 52 weeks follow‐up. Ten Patients (5 male, 8 bilateral, median [interquartile range] age 40 [30–59] years, 3 BOS2, 7 BOS3) participated. MSC treatment was well tolerated with all patients receiving the full dosing schedule without any procedure‐related serious adverse events. The rate of decline in forced expiratory volume in one second slowed after the MSC infusions (120 ml/month preinfusion vs. 30 ml/month postinfusion, p = .08). Two patients died at 152 and 270 days post‐MSC treatment, both from progressive CLAD. In conclusion, infusion of allogeneic bone marrow‐derived MSCs is feasible and safe even in patients with advanced CLAD. Stem Cells Translational Medicine 2017;6:1152–1157