A comparison of echocardiography to invasive measurement in the evaluation of pulmonary arterial hypertension in a rat model

Pulmonary arterial hypertension (PAH) is a life-threatening condition characterized by progressive elevation in pulmonary artery pressure (PAP) and total pulmonary vascular resistance (TPVR). Recent advances in imaging techniques have allowed the development of new echocardiographic parameters to evaluate disease progression. However, there are no reports comparing the diagnostic performance of these non-invasive parameters to each other and to invasive measurements. Therefore, we investigated the diagnostic yield of echocardiographically derived TPVR and Doppler parameters of PAP in screening and measuring the severity of PAH in a rat model. Serial echocardiographic and invasive measurements were performed at baseline, 21 and 35 days after monocrotaline-induction of PAH. The most challenging echocardiographic derived TPVR measurement had good correlation with the invasive measurement (r = 0.92, P < 0.001) but also more simple and novel parameters of TPVR were found to be useful although the non-invasive TPVR measurement was feasible in only 29% of the studies due to lack of sufficient tricuspid valve regurgitation. However, echocardiographic measures of PAP, pulmonary artery flow acceleration time (PAAT) and deceleration (PAD), were measurable in all animals, and correlated with invasive PAP (r = −0.74 and r = 0.75, P < 0.001 for both). Right ventricular thickness and area correlated with invasive PAP (r = 0.59 and r = 0.64, P < 0.001 for both). Observer variability of the invasive and non-invasive parameters was low except in tissue-Doppler derived isovolumetric relaxation time. These non-invasive parameters may be used to replace invasive measurements in detecting successful disease induction and to complement invasive data in the evaluation of PAH severity in a rat model

Induction and regulation of matrix metalloproteinase-12in human airway smooth muscle cells

BACKGROUND: The elastolytic enzyme matrix metalloproteinase (MMP)-12 has been implicated in the development of airway inflammation and remodeling. We investigated whether human airway smooth muscle cells could express and secrete MMP-12, thereby participating in the pathogenesis of airway inflammatory diseases. METHODS: Laser capture microdissection was used to collect smooth muscle cells from human bronchial biopsy sections. MMP-12 mRNA expression was analysed by quantitative real-time RT-PCR. MMP-12 protein expression and secretion from cultured primary airway smooth muscle cells was further analysed by Western blot. MMP-12 protein localization in bronchial tissue sections was detected by immunohistochemistry. MMP-12 activity was determined by zymography. The TransAM AP-1 family kit was used to measure c-Jun activation and nuclear binding. Analysis of variance was used to determine statistical significance. RESULTS: We provide evidence that MMP-12 mRNA and protein are expressed by in-situ human airway smooth muscle cells obtained from bronchial biopsies of normal volunteers, and of patients with asthma, COPD and chronic cough. The pro-inflammatory cytokine, interleukin (IL)-1β, induced a >100-fold increase in MMP-12 gene expression and a >10-fold enhancement in MMP-12 activity of primary airway smooth muscle cell cultures. Selective inhibitors of extracellular signal-regulated kinase, c-Jun N-terminal kinase and phosphatidylinositol 3-kinase reduced the activity of IL-1β on MMP-12, indicating a role for these kinases in IL-1β-induced induction and release of MMP-12. IL-1β-induced MMP-12 activity and gene expression was down-regulated by the corticosteroid dexamethasone but up-regulated by the inflammatory cytokine tumour necrosis factor (TNF)-α through enhancing activator protein-1 activation by IL-1β. Transforming growth factor-β had no significant effect on MMP-12 induction. CONCLUSION: Our findings indicate that human airway smooth muscle cells express and secrete MMP-12 that is up-regulated by IL-1β and TNF-α. Bronchial smooth muscle cells may be an important source of elastolytic activity, thereby participating in remodeling in airway diseases such as COPD and chronic asthma

SPINAL NEURILEMOMAS AND NEUROFIBROMAS - CENTRAL DOT SIGN IN POSTGADOLINIUM MRI

The MR studies of three histologically proven spinal neurilemmomas and neurofibromas were reviewed retrospectively. There were two benign neurilemmomas (schwannomas) and one neurofibroma. The common characteristic of these cases was a central low intensity focus (”dot”) seen on postcontrast T1-weighted imaging. The low intensity foci corresponded histologically to a congeries of changes including edema, microcysts, foam cells, hyalinization of blood vessels, old hemorrhage, and dystrophic calcification

Ambulatory oxygen for treatment of exertional hypoxaemia in pulmonary fibrosis (PFOX trial): a randomised controlled trial

INTRODUCTION: Interstitial lung diseases are characterised by scarring of lung tissue that leads to reduced transfer of oxygen into the blood, decreased exercise capacity and premature death. Ambulatory oxygen therapy may be used to treat exertional oxyhaemoglobin desaturation, but there is little evidence to support its efficacy and there is wide variation in clinical practice. This study aims to compare the clinical efficacy and cost-effectiveness of ambulatory oxygen versus ambulatory air in people with fibrotic interstitial lung disease and exertional desaturation. METHODS AND ANALYSIS: A randomised, controlled trial with blinding of participants, clinicians and researchers will be conducted at trial sites in Australia and Sweden. Eligible participants will be randomised 1:1 into two groups. Intervention participants will receive ambulatory oxygen therapy using a portable oxygen concentrator (POC) during daily activities and control participants will use an identical POC modified to deliver air. Outcomes will be assessed at baseline, 3 months and 6 months. The primary outcome is change in physical activity measured by number of steps per day using a physical activity monitor (StepWatch). Secondary outcomes are functional capacity (6-minute walk distance), health-related quality of life (St George Respiratory Questionnaire, EQ-5D-5L and King's Brief Interstitial Lung Disease Questionnaire), breathlessness (Dyspnoea-12), fatigue (Fatigue Severity Scale), anxiety and depression (Hospital Anxiety and Depression Scale), physical activity level (GENEActive), oxygen saturation in daily life, POC usage, and plasma markers of skeletal muscle metabolism, systematic inflammation and oxidative stress. A cost-effectiveness evaluation will also be undertaken. ETHICS AND DISSEMINATION: Ethical approval has been granted in Australia by Alfred Hospital Human Research Ethics Committee (HREC/18/Alfred/42) with governance approval at all Australian sites, and in Sweden (Lund Dnr: 2019-02963). The results will be published in peer-reviewed scientific journals, presented at conferences and disseminated to consumers in publications for lay audiences. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT03737409)