Search PubMed⌕ Search

Biomedical subjects

Paul W Noble

Publications and source records attributed to Paul W Noble.

18 recordsLinked to original sources
PubMed2006

Idiopathic pulmonary fibrosis: natural history and prognosis.

Idiopathic pulmonary fibrosis (IPF) is associated with a poor prognosis, although considerable interpatient heterogeneity may be observed. Baseline dyspnea, lung function abnormalities, and gas exchange impairments are predictive of outcome, but recent evidence suggests the change in these parameters over time is as predictive, and in some cases more predictive, of outcome. A change in forced vital capacity > or =10% may be an important surrogate marker for mortality risk in IPF patients. Histologic analysis shows the deposition of interstitial connective tissue and granulation tissue leading to formation of fibroblastic foci. Thus, ongoing epithelial damage and repair processes associated with persistent fibroblastic proliferation seem important in IPF natural history.

Humans↗
PubMed2005

Regulation of lung injury and repair by Toll-like receptors and hyaluronan.

Mechanisms that regulate inflammation and repair after acute lung injury are incompletely understood. The extracellular matrix glycosaminoglycan hyaluronan is produced after tissue injury and impaired clearance results in unremitting inflammation. Here we report that hyaluronan degradation products require MyD88 and both Toll-like receptor (TLR)4 and TLR2 in vitro and in vivo to initiate inflammatory responses in acute lung injury. Hyaluronan fragments isolated from serum of individuals with acute lung injury stimulated macrophage chemokine production in a TLR4- and TLR2-dependent manner. Myd88(-/-) and Tlr4(-/-)Tlr2(-/-) mice showed impaired transepithelial migration of inflammatory cells but decreased survival and enhanced epithelial cell apoptosis after lung injury. Lung epithelial cell-specific overexpression of high-molecular-mass hyaluronan was protective against acute lung injury. Furthermore, epithelial cell-surface hyaluronan was protective against apoptosis, in part, through TLR-dependent basal activation of NF-kappaB. Hyaluronan-TLR2 and hyaluronan-TLR4 interactions provide signals that initiate inflammatory responses, maintain epithelial cell integrity and promote recovery from acute lung injury.

Animals↗
PubMed2005

Cutting edge: TLR4 deficiency confers susceptibility to lethal oxidant lung injury.

TLRs have been studied extensively in pathogen-mediated host responses. We use a murine model of lethal oxidant-mediated injury to demonstrate for the first time that mammalian TLR4 is required for survival and lung integrity. Administering high levels of inspired oxygen, or hyperoxia, is commonly used as a life-sustaining measure in critically ill patients. However, prolonged exposures can lead to respiratory failure and death. TLR4-deficient mice exhibited increased mortality and lung injury during hyperoxia. The enhanced susceptibility of TLR4-deficient mice to hyperoxia was associated with an inability to up-regulate Bcl-2 and phospho-Akt. Restoration of Bcl-2 and phospho-Akt levels by the exogenous transfer of the antioxidant gene heme oxygenase-1 markedly attenuated hyperoxia-induced injury, apoptosis, and mortality in TLR4-deficient mice. Taken together, our results suggest a protective role of TLR4 in oxidant-mediated injury, providing novel mechanistic links among innate immunity, oxidant stress, and apoptosis.

Animals↗
PubMed2005

The clinical course of patients with idiopathic pulmonary fibrosis.

BACKGROUND: Prospective data defining the clinical course in idiopathic pulmonary fibrosis (IPF) are sparse. OBJECTIVE: To analyze the clinical course of patients with mild to moderate IPF. DESIGN: Analysis of data from the placebo group of a randomized, controlled trial evaluating interferon-gamma1b. SETTING: Academic and community medical centers. PATIENTS: 168 patients in the placebo group of a trial evaluating interferon-gamma1b. MEASUREMENTS: Measures of physiology and dyspnea assessed at 12-week intervals; hospitalizations; and the pace of deterioration and cause of death over a median period of 76 weeks. RESULTS: Physiologic variables changed minimally during the study. However, 23% of patients required hospitalization for a respiratory disorder and 21% died. Idiopathic pulmonary fibrosis was the primary cause of death in 89% of patients who died, and an apparent acute clinical deterioration preceded death in 47% of these patients. LIMITATIONS: The instrument used to define the pace of deterioration and cause of death was applied retrospectively. CONCLUSIONS: Recognition of the common occurrence of acute fatal deterioration in patients with mild to moderate IPF has important implications for monitoring patients and supports early referral for lung transplantation.

Aged↗
PubMed2005

Analyses of efficacy end points in a controlled trial of interferon-gamma1b for idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a devastating disease, yet validated, reliable criteria for evaluating patient response to therapies in clinical trials are lacking. METHODS: To optimize selection of end point criteria for the study of interferon (IFN)-gamma1b in patients with IPF, we retrospectively analyzed the components of the primary efficacy end point used in a large, controlled study of 330 patients for reliability, validity, and sensitivity to treatment effect. The primary end point components were death, disease progression defined as a > or = 5 mm Hg increase in resting alveolar-arterial oxygen pressure gradient (P[A-a]O2), and disease progression defined as a > or = 10% decrease in percentage of predicted FVC. RESULTS: We found that the P(A-a)O2 criterion was not reliable and was not associated with mortality. In contrast, the FVC criterion was reliable and was associated with a 2.4-fold increase in the risk of death. Of the three measures, only mortality was sensitive to a treatment effect of IFN-gamma1b. Additionally, the tendency for mortality benefit was observed in nearly all patient subgroups defined by baseline physiology. The effect of IFN-gamma1b on mortality was strongest in patients with baseline percentage of predicted FVC > or = 55% (p = 0.004) or percentage of predicted diffusing capacity of the lung for carbon monoxide > or = 30% (p = 0.008). CONCLUSION: We conclude that mortality is the most inclusive end point for future trials of IFN- gamma1b in patients with IPF, and that a > 10% decrement in the percentage of predicted FVC represents a valid measure of disease progression.

Adult↗
PubMed2005

Case study review.

Examining case studies from patients with interstitial lung diseases (ILDs) is important in order to evaluate current diagnosis and treatment options. Two cases will be discussed; the first case examines a patient with usual interstitial pneumonia, and the second case examines a patient with subacute ILD and elements to suggest a forme fruste presentation of an unclassifiable connective tissue disease. Each case highlights components of the differential diagnosis, as well as reviews the treatments and prognoses of these patients. The cases provide clinical pearls that are designed to enhance the reader's understanding of ILDs.

Aged↗
PubMed2004

Early growth response gene 1-mediated apoptosis is essential for transforming growth factor beta1-induced pulmonary fibrosis.

Fibrosis and apoptosis are juxtaposed in pulmonary disorders such as asthma and the interstitial diseases, and transforming growth factor (TGF)-beta(1) has been implicated in the pathogenesis of these responses. However, the in vivo effector functions of TGF-beta(1) in the lung and its roles in the pathogenesis of these responses are not completely understood. In addition, the relationships between apoptosis and other TGF-beta(1)-induced responses have not been defined. To address these issues, we targeted bioactive TGF-beta(1) to the murine lung using a novel externally regulatable, triple transgenic system. TGF-beta(1) produced a transient wave of epithelial apoptosis that was followed by mononuclear-rich inflammation, tissue fibrosis, myofibroblast and myocyte hyperplasia, and septal rupture with honeycombing. Studies of these mice highlighted the reversibility of this fibrotic response. They also demonstrated that a null mutation of early growth response gene (Egr)-1 or caspase inhibition blocked TGF-beta(1)-induced apoptosis. Interestingly, both interventions markedly ameliorated TGF-beta(1)-induced fibrosis and alveolar remodeling. These studies illustrate the complex effects of TGF-beta(1) in vivo and define the critical role of Egr-1 in the TGF-beta(1) phenotype. They also demonstrate that Egr-1-mediated apoptosis is a prerequisite for TGF-beta(1)-induced fibrosis and remodeling.

Actins↗
PubMed2004

A placebo-controlled trial of interferon gamma-1b in patients with idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis is a progressive, fatal disease with no known efficacious therapy. METHODS: In a double-blind, multinational trial, we randomly assigned 330 patients with idiopathic pulmonary fibrosis that was unresponsive to corticosteroid therapy to receive subcutaneous interferon gamma-1b or placebo. RESULTS: Over a median of 58 weeks, interferon gamma-1b therapy did not significantly affect the primary end point of progression-free survival, defined as the time to disease progression or death, and no significant treatment effect was observed on measures of lung function, gas exchange, or the quality of life. Ten percent of patients in the interferon gamma-1b group died, as compared with 17 percent of patients in the placebo group (P=0.08). Treatment with interferon gamma-1b was associated with more frequent constitutional symptoms. However, the rates of treatment adherence and premature discontinuation of treatment were similar in the two groups. More pneumonias were reported among patients in the interferon gamma-1b group, but the incidence of severe or life-threatening respiratory tract infections was similar in the two groups. CONCLUSIONS: In a well-defined population of patients with idiopathic pulmonary fibrosis, interferon gamma-1b did not affect progression-free survival, pulmonary function, or the quality of life. Owing to the size and duration of the trial, a clinically significant survival benefit could not be ruled out.

Disease Progression↗
PubMed2004

Idiopathic pulmonary fibrosis: new insights into pathogenesis.

The combination of the unique pathologic features of usual interstitial pneumonia (UIP) on biopsy, the progressive clinical course, and resistance to anti-inflammatory therapy constitutes the cardinal manifestations of what is termed idiopathic pulmonary fibrosis (IFP)/usual interstitial pneumonia, and it has led to recent suggestions that new therapies should be directed at regulating fibroblast functions rather than targeting the inflammatory response. The observation that "early" UIP looks like "late" UIP but there is less of it has been largely responsible for re-evaluation of the paradigm that IPF is the result of uncontrolled lung inflammation. This article highlights aspects of current thoughts on pathogenesis of IFP and expands on recent reviews.

Apoptosis↗
PubMed2004

Regulation of pulmonary fibrosis by chemokine receptor CXCR3.

CXC chemokine receptor 3 (CXCR3) is the receptor for the IFN-gamma-inducible C-X-C chemokines MIG/CXCL9, IP-10/CXCL10, and I-TAC/CXCL11. CXCR3 is expressed on activated immune cells and proliferating endothelial cells. The role of CXCR3 in fibroproliferation has not been investigated. We examined the role of CXCR3 in pulmonary injury and repair in vivo. CXCR3-deficient mice demonstrated increased mortality with progressive interstitial fibrosis relative to WT mice. Increased fibrosis occurred without increased inflammatory cell recruitment. CXCR3 deficiency resulted in both a reduced early burst of IFN-gamma production and decreased expression of CXCL10 after lung injury. We identified a relative deficiency in lung NK cells in the unchallenged CXCR3-deficient lung and demonstrated production of IFN-gamma by WT lung NK cells in vivo following lung injury. The fibrotic phenotype in the CXCR3-deficient mice was significantly reversed following administration of exogenous IFN-gamma or restoration of endogenous IFN-gamma production by adoptive transfer of WT lymph node and spleen cells. Finally, pretreatment of WT mice with IFN-gamma-neutralizing Ab's enhanced fibrosis following lung injury. These data demonstrate a nonredundant role for CXCR3 in limiting tissue fibroproliferation and suggest that this effect may be mediated, in part, by the innate production of IFN-gamma following lung injury.

Adoptive Transfer↗
PubMed2003

Small interfering RNA targeting heme oxygenase-1 enhances ischemia-reperfusion-induced lung apoptosis.

Heme oxygenase-1 (HO-1) is emerging as an important cytoprotective enzyme system in a variety of injury models. To optimize future therapeutic applications of HO-1, it is necessary to delineate the precise functions and mechanisms as well as modes of externally regulating HO-1 expression. Investigations have been limited by difficulties with the generation of HO-1 null mice and the lack of specific HO-1 inhibitors. Lung ischemia-reperfusion (I-R) injury is the inciting event in acute lung failure following transplantation, surgery, and shock. To study the function of HO-1 in I-R-induced lung injury, we designed small interfering RNA (siRNA) sequences that effectively suppress HO-1 expression both in vitro and in vivo in an organ-specific manner. In this study we show that there is enhanced apoptosis, via increased Fas expression and caspase 3 activity, in the presence of HO-1 siRNA in endothelial cells and mouse lung during I-R injury, whereas HO-1 overexpression attenuates apoptosis. To the best of our knowledge, we are the first to demonstrate that lung-specific siRNA delivery can be achieved by intranasal administration without the need for viral vectors or transfection agents in vivo, thereby obviating potential concerns for toxicity if siRNA technology is to have clinical application in the future.

Animals↗
PubMed2002

Resolution of lung inflammation by CD44.

Successful repair after tissue injury and inflammation requires resolution of the inflammatory response and removal of extracellular matrix breakdown products. We have examined whether the cell-surface adhesion molecule and hyaluronan receptor CD44 plays a role in resolving lung inflammation. CD44-deficient mice succumb to unremitting inflammation following noninfectious lung injury, characterized by impaired clearance of apoptotic neutrophils, persistent accumulation of hyaluronan fragments at the site of tissue injury, and impaired activation of transforming growth factor-beta1. This phenotype was partially reversed by reconstitution with CD44+ cells, thus demonstrating a critical role for this receptor in resolving lung inflammation.

Animals↗
PubMed2002

CD44 deficiency leads to enhanced neutrophil migration and lung injury in Escherichia coli pneumonia in mice.

CD44 is a major cell-surface receptor for hyaluronic acid (HA), a glycosaminoglycan component of extracellular matrix. HA-CD44 interactions have been implicated in leukocyte extravasation into an inflammatory site. This study examined the role of CD44 in acute inflammatory responses during pneumonias induced by Escherichia coli and Streptococcus pneumoniae using CD44-deficient mice. In E. coli-induced pneumonia, neutrophil accumulation in the lungs and edema formation was increased by 84% and 88%, respectively, in CD44-deficient mice compared to wild-type mice. In contrast, no difference was observed between these genotypes in S. pneumoniae-induced pneumonia, and the HA content in the lungs decreased after instillation of S. pneumoniae, but not E. coli, in both genotypes. Studies to determine the mechanisms for this enhanced response showed that: 1) neutrophil apoptosis was not different between these two genotypes in either type of pneumonia; 2) CD44 deficiency resulted in enhanced mRNA expression of several inflammatory genes; and 3) CD44-deficient neutrophils migrated through Matrigel in response to chemoattractants faster and in greater numbers than wild-type neutrophils in vitro and this increase was in part dependent on HA content in the Matrigel. These data demonstrate that CD44 deficiency results in enhanced inflammation in E. coli but not S. pneumoniae-induced pneumonia, suggesting a previously unrecognized role for CD44 in limiting the inflammatory response to E. coli.

Animals↗
PubMed2002

Hyaluronan and its catabolic products in tissue injury and repair.

Hyaluronan is an unbiquitous glycosaminoglycan present in most tissues. Under homeostatic conditions hyaluronan exists as a high molecular mass polymer that has important roles in tissue structural integrity. Under conditions of stress such as following tissue injury, hyaluronan becomes depolymerized and lower molecular mass polymers are generated. The biological properties of these hyaluronan fragments appear to be distinct from the larger precursor molecules. This review examines the biological role of hyaluronan fragments in tissue injury and repair.

Animals↗