Cluster analysis identifies novel real-world lung disease-pulmonary hypertension subphenotypes: implications for treatment response.

Background: Clinical trials repurposing pulmonary arterial hypertension (PAH) therapies to patients with lung disease- or hypoxia-pulmonary hypertension (PH) (classified as World Health Organization Group 3 PH) have failed to show a consistent benefit. However, Group 3 PH clinical heterogeneity suggests robust phenotyping may inform detection of treatment-responsive subgroups. We hypothesised that cluster analysis would identify subphenotypes with differential responses to oral PAH therapy.

Real-world use of inhaled treprostinil for lung disease-pulmonary hypertension: A protocol for patient evaluation and prescribing.

Inhaled treprostinil was approved recently for interstitial lung disease-pulmonary hypertension; however, efficacy in "real-world" populations is not known. We designed a protocol and report our experience evaluating 10 patients referred for therapy. Misdiagnosis at presentation was common; ultimately, three patients (30%) were prescribed drug.

Tadalafil for veterans with chronic obstructive pulmonary disease-pulmonary hypertension: A multicenter, placebo-controlled randomized trial.

Treating Veterans with chronic obstructive pulmonary disease complicated by pulmonary hypertension (COPD-PH) using phosphodiesterase type-5 inhibitor pharmacotherapy is common, but efficacy data are lacking. To address this further, patients with COPD-PH from five Department of Veterans Affairs hospitals were randomized (1∶1) to receive placebo or oral tadalafil (40 mg/day) for 12 months. The primary endpoint was changed from baseline in 6-min walk distance at 12 months.

Pulmonary vascular resistance and clinical outcomes in patients with pulmonary hypertension: a retrospective cohort study.

Background: In pulmonary hypertension subgroups, elevated pulmonary vascular resistance (PVR) of 3·0 Wood units or more is associated with poor prognosis. However, the spectrum of PVR risk in pulmonary hypertension is not known. To address this area of uncertainty, we aimed to analyse the relationship between PVR and adverse clinical outcomes in pulmonary hypertension.

Association of Borderline Pulmonary Hypertension With Mortality and Hospitalization in a Large Patient Cohort: Insights From the Veterans Affairs Clinical Assessment, Reporting, and Tracking Program.

Background: Pulmonary hypertension (PH) is associated with increased morbidity across the cardiopulmonary disease spectrum. Based primarily on expert consensus opinion, PH is defined by a mean pulmonary artery pressure (mPAP) ≥25 mm Hg. Although mPAP levels below this threshold are common among populations at risk for PH, the relevance of mPAP <25 mm Hg to clinical outcome is unknown.

Protocol for exercise hemodynamic assessment: performing an invasive cardiopulmonary exercise test in clinical practice.

Invasive cardiopulmonary exercise testing (iCPET) combines full central hemodynamic assessment with continuous measurements of pulmonary gas exchange and ventilation to help in understanding the pathophysiology underpinning unexplained exertional intolerance. There is increasing evidence to support the use of iCPET as a key methodology for diagnosing heart failure with preserved ejection fraction and exercise-induced pulmonary hypertension as occult causes of exercise limitation, but there is little information available outlining the methodology to use this diagnostic test in clinical practice. To bridge this knowledge gap, the operational protocol for iCPET at our institution is discussed in detail.

Study design and rationale for investigating phosphodiesterase type 5 inhibition for the treatment of pulmonary hypertension due to chronic obstructive lung disease: the TADA-PHiLD (TADAlafil for Pulmonary Hypertension associated with chronic obstructive Lung Disease) trial.

In patients with chronic obstructive pulmonary disease (COPD), moderate or severe pulmonary hypertension (COPD-PH) is associated with increased rates of morbidity and mortality. Despite this, approaches to treatment and the efficacy of phosphodiesterase type 5 inhibition (PDE-5i) in COPD-PH are unresolved. We present the clinical rationale and study design to assess the effect of oral tadalafil on exercise capacity, cardiopulmonary hemodynamics, and clinical outcome measures in COPD-PH patients.

Cellular FLICE-like inhibitory protein deviates myofibroblast fas-induced apoptosis toward proliferation during lung fibrosis.

A prominent feature of fibrotic tissue in general and of lungs in particular is fibroblast proliferation and accumulation. In patients overcoming fibrosis, apoptosis limits this excessive cell growth. We have previously shown resistance to Fas-induced apoptosis of primary lung fibroblasts from mice with bleomycin-induced lung fibrosis, their escape from immune surveillance, and continued accumulation in spite of overexpression of the Fas death receptor.

Transcriptional changes associated with recovery from heart failure in the SHR.

To identify biological pathways associated with myocardial recovery from heart failure (HF), gene profiling and gene set enrichment analysis (GSEA) were examined in left ventricle of spontaneously hypertensive rats with HF (SHR-F) with no treatment, following treatment with the angiotensin converting enzyme inhibitor captopril, and treatment with captopril combined with the short chain fatty acid derivative phenylbutyrate. Failing hearts demonstrated depressed left ventricular ejection fraction, while ventricular volume and mass increased. Captopril treatment alone prevented further deterioration but did not improve myocardial function; relatively few transcripts were differentially expressed relative to untreated SHR-F.

Transition from compensated hypertrophy to systolic heart failure in the spontaneously hypertensive rat: Structure, function, and transcript analysis.

Gene expression, determined by micro-array analysis, and left ventricular (LV) remodeling associated with the transition to systolic heart failure (HF) were examined in the spontaneously hypertensive rat (SHR). By combining transcript and gene set enrichment analysis (GSEA) of the LV with assessment of function and structure in age-matched SHR with and without HF, we aimed to better understand the molecular events underlying the onset of hypertensive HF. Failing hearts demonstrated depressed LV ejection fraction, systolic blood pressure, and LV papillary muscle force while LV end-diastolic and systolic volume and ventricular mass increased.

Activation of elastin transcription by transforming growth factor-beta in human lung fibroblasts.

Elastin synthesis is essential for lung development and postnatal maturation as well as for repair following injury. Using human embryonic lung fibroblasts that express undetectable levels of elastin as assessed by Northern analyses, we found that treatment with exogenous transforming growth factor-beta (TGF-beta) induced rapid and transient increases in levels of elastin heterogeneous nuclear RNA (hnRNA) followed by increases of elastin mRNA and protein expression. In fibroblasts derived from transgenic mice, TGF-beta induced increases in the expression of a human elastin gene promoter fragment driving a chloramphenicol acetyl transferase reporter gene.

Fibulin-5 gene expression in human lung fibroblasts is regulated by TGF-beta and phosphatidylinositol 3-kinase activity.

Fibulin-5 (FBLN5), an extracellular matrix glycoprotein required for normal elastogenesis, is coordinately expressed with elastin during lung injury and repair. We found that treatment with transforming growth factor-beta (TGF-beta) induced a rapid but transient increase in FBLN5 heterogeneous nuclear RNA (hnRNA) followed by a sustained increased in the steady-state level of FBLN5 mRNA. The transcription start site of the human FBLN5 gene was localized at 221 nucleotides upstream of the translation start site by using primer extension, Northern blots, and functional analysis of transcriptional activity in reporter plasmids containing 5'-flanking regions.

Modulation of amino acid uptake by TGF-beta in lung myofibroblasts.

Hormones such as insulin, growth factors, and cell stress stimulate system A amino acid transporter. Transforming growth factor-beta (TGF-beta) stimulates amino acid uptake thereby inducing cell proliferation, cellular hypertrophy, and matrix synthesis. Insulin appears to activate amino acid in smooth muscle cells via a phosphatidylinositol 3-kinase (PI3-kinase)-dependent pathway.

Induction of the myofibroblast phenotype following elastolytic injury to mouse lung.

The repair of alveolar structures following endotracheal administration of porcine pancreatic elastase (PPE) to mice involves the coordinated deposition of new matrix elements. We determined the induction of the myofibroblast phenotype following elastolytic injury to mouse lung by examining the expression of alpha-smooth muscle actin (alpha-SMA) by immunohistochemistry. We also examined elastin and alpha1(I) collagen mRNA expression by in situ hybridization.

Formation of lung alveolar-like structures in collagen-glycosaminoglycan scaffolds in vitro.

The objective of this study was to investigate the histology of tissue formed when fetal rat lung cells were grown in a collagen-glycosaminoglycan (GAG) tissue-engineering scaffold. The goal was the formation of lung histotypic structures in the tissue-engineering scaffolds in vitro. Achieving this goal would facilitate future investigations of the effects of selected scaffold design parameters on processes that may underlie aspects of lung regeneration in vivo.

Interleukin-1beta induces osteopontin expression in pulmonary fibroblasts.

Osteopontin is a multifunctional matricellular protein identified as one of the most upregulated genes in pulmonary fibrosis. Experimental animal models have identified early pro-fibrotic cytokines as essential to the pathogenesis of inflammation-induced pulmonary fibrosis. However, the principal sources of osteopontin in the fibroproliferative lung, and the factors responsible for its induction, have not been fully defined.

Methods for measuring type I collagen synthesis in vitro.

The excess accumulation of type I collagen within tissues leads to organ dysfunction and occurs as a result of an imbalance between synthesis and degradation. This chapter outlines several methods to assess the in vitro production of type I collagen that are employed in our laboratory. We describe Western immunoblotting of intact alpha1(I) collagen using antibodies directed to alpha1(I) collagen amino and carboxyl propeptides.

Hypoxia suppresses elastin repair by rat lung fibroblasts.

Macrophage and neutrophil proteinases damage lung elastin, disrupting alveolar epithelium and filling alveoli with inflammatory exudate. Alveolar collapse and regional hypoxia occur. Whether low oxygen tension alters fibroblast-mediated lung repair is unknown.

Engraftment of neonatal lung fibroblasts into the normal and elastase-injured lung.

Interstitial fibroblasts are an integral component of the alveolar wall. These cells produce matrix proteins that maintain the extracellular scaffold of alveolar structures. Emphysema is characterized by airspace enlargement resulting from the loss of alveolar cellularity and matrix.

Regulation of elastin gene transcription by proteasome dysfunction.

Elastin, a major extracellular matrix protein and the core component of elastic fiber, is essential to maintain lung structural integrity and normal physiological function. We previously found that the downregulation of elastin gene transcription by IL-1beta is mediated via activation of NF-kappaB and CCAAT/enhancer binding protein (C/EBP)beta, both targets of the ubiquitin-proteasome pathway. To further investigate the molecular mechanisms that underlie the control of elastin gene expression, we disrupted the ubiquitin-proteasome pathway with specific proteasome inhibitors.

Elastase mediates the release of growth factors from lung in vivo.

Uncontrolled elastase activity is involved in the development of several types of lung disease. Previous reports demonstrated that growth factors are liberated from pulmonary matrix storage sites by elastase; however, release of these entities in vivo is not well defined. In the present study, we investigated the release of fibroblast growth factor-2 (FGF-2) and transforming growth factor-beta (TGF-beta), after intratracheal instillation of porcine pancreatic elastase into mice.

Phenylbutyrate decreases type I collagen production in human lung fibroblasts.

Fibrotic lung diseases are characterized by excess extracellular matrix production, in particular type I collagen. Phenylbutyrate (PB) is a non-toxic pharmacological compound that functions as a weak histone deacetylase inhibitor. In hepatic stellate cells, the synthesis of type I collagen expression is decreased by inhibiting histone acetylation.

Coordinate expression of fibulin-5/DANCE and elastin during lung injury repair.

Fibulin-5, previously known as DANCE and EVEC, is a secreted extracellular matrix protein that functions as a scaffold for elastin fiber assembly and as a ligand for integrins alphavbeta3, alphavbeta5, and alpha9beta1. Fibulin-5 is developmentally regulated in the lung, and lung air space enlargement develops in mice deficient in fibulin-5. Fibulin-5 is also induced in adult lung following lung injury by hyperoxia.

Regulation of elastin gene transcription by interleukin-1 beta-induced C/EBP beta isoforms.

We previously showed that interleukin (IL)-1beta decreases elastin gene transcription through activation of the NF-kappaB subunit p65 in neonatal rat lung fibroblasts. The present study was undertaken to further explore the molecular mechanisms responsible for the inhibitory effect of IL-1beta on elastin gene transcription. We found that cycloheximide blocked IL-1beta-induced downregulation of elastin mRNA but did not inhibit IL-1beta-induced translocation of p65 into the nucleus.

Retinoic acid does not affect alveolar septation in adult FVB mice with elastase-induced emphysema.

Background: Administration of ALL-TRANS retinoic acid (ATRA) to adult Sprague-Dawley rats with emphysema induced by porcine pancreatic elastase (PPE) reversed the emphysema perhaps by inducing new alveolar formation.

Objective: A study was conducted to determine whether ATRA can induce new alveolar septa and reverse the airspace enlargement caused in adult mice by PPE treatment.

Methods: 48 FVB mice were divided into 6 groups.