Pierre Ernst

Bio: Pierre Ernst is an academic researcher from McGill University. The author has contributed to research in topics: Asthma & COPD. The author has an hindex of 64, co-authored 232 publications receiving 16614 citations. Previous affiliations of Pierre Ernst include Jewish General Hospital & McGill University Health Centre.

The Use of β-Agonists and the Risk of Death and near Death from Asthma

Abstract: Background. Morbidity and mortality from asthma appear to be increasing, and it has been suggested that medications used to treat asthma are contributing to this trend. We investigated a possible association between death or near death from asthma and the regular use of β2-agonist bronchodilators. Methods. Using linked health insurance data bases from Saskatchewan, Canada, we conducted a matched case–control study of subjects drawn from a cohort of 12,301 patients for whom asthma medications had been prescribed between 1978 and 1987. We matched 129 case patients who had fatal or near-fatal asthma with 655 controls (who had received medications for asthma but had not had fatal or near-fatal events) with respect to region of residence, age, receipt of social assistance, and previous hospitalization for asthma. Results. The use of β-agonists administered by a metered-dose inhaler was associated with an increased risk of death from asthma (odds ratio, 2.6 per canister per month; 95 percent confidence...

Low-dose inhaled corticosteroids and the prevention of death from asthma.

Abstract: Background Although inhaled corticosteroids are effective for the treatment of asthma, it is uncertain whether their use can prevent death from asthma. Methods We used the Saskatchewan Health data bases to form a population-based cohort of all subjects from 5 through 44 years of age who were using antiasthma drugs during the period from 1975 through 1991. We followed subjects until the end of 1997, their 55th birthday, death, emigration, or termination of health insurance coverage, whichever came first. We conducted a nested case–control study in which subjects who died of asthma were matched with controls within the cohort according to the length of follow-up at the time of death of the case patient (the index date), the date of study entry, and the severity of asthma. We calculated rate ratios after adjustment for the subject's age and sex; the number of prescriptions of theophylline, nebulized and oral β-adrenergic agonists, and oral corticosteroids in the year before the index date; the number of cani...

Eosinophil-associated TGF-beta1 mRNA expression and airways fibrosis in bronchial asthma.

Abstract: The histopathology of bronchial asthma is associated with structural changes within the airways, including subepithelial fibrosis, as well as chronic eosinophilic inflammation. The mechanisms responsible for this tissue remodeling, and in particular the role of inflammatory cells, remain to be established. Transforming growth factor-β (TGF-β) is a potent profibrotic cytokine which may contribute to the thickening of the reticular lamina by the deposition of collagen fibers. To investigate the molecular mechanisms underlying these structural changes, we have investigated the expression of TGF-β1 mRNA and immunoreactivity within the bronchial mucosa of mild to severe asthmatic individuals and normal control subjects using the techniques of in situ hybridization and immunocytochemistry. As eosinophils are prominent within the asthmatic airway and are known to synthesize pro-inflammatory cytokines, the presence of TGF-β1 mRNA and immunoreactive protein in eosinophils was also examined. Asthmatic individuals e...

Long-term natural history of chronic obstructive pulmonary disease: severe exacerbations and mortality

Abstract: Background The long-term natural history of chronic obstructive pulmonary disease (COPD) in terms of successive severe exacerbations and mortality is unknown. Methods The authors formed an inception cohort of patients from their first ever hospitalisation for COPD during 1990e2005, using the healthcare databases from the province of Quebec, Canada. Patients were followed until death or 31 March 2007, and all COPD hospitalisations occurring during follow-up were identified. The hazard functions of successive hospitalised COPD exacerbations and all-cause mortality over time were estimated, and HRs adjusted for age, sex, calendar time and comorbidity. Results The cohort included 73106 patients hospitalised for the first time for COPD, of whom 50580 died during the 17-year follow-up, with 50% and 75% mortality at 3.6 and 7.7 years respectively. The median time from the first to the second hospitalised exacerbation was around 5 years and decreased to <4 months from the 9th to the 10th. The risk of the subsequent severe exacerbation was increased threefold after the second severe exacerbation and 24-fold after the 10th, relative to the first. Mortality after a severe exacerbation peaked to 40 deaths per 10000 per day in the first week after admission, dropping gradually to 5 after 3 months. Conclusions The course of COPD involves a rapid decline in health status after the second severe exacerbation and high mortality in the weeks following every severe exacerbation. Two strategic targets for COPD management should include delaying the second severe exacerbation and improving treatment of severe exacerbations to reduce their excessive early mortality.

Increased formation of the potent oxidant peroxynitrite in the airways of asthmatic patients is associated with induction of nitric oxide synthase: effect of inhaled glucocorticoid

Abstract: Peroxynitrite is a potent oxidant formed by the rapid reaction of the free radicals nitric oxide (NO) and superoxide. It causes airway hyperresponsiveness and airway epithelial damage, enhances inflammatory cell recruitment, and inhibits pulmonary surfactant. Asthma is characterized by increased airway hyperresponsiveness, airway epithelial shedding, and inflammation. We examined the production of peroxynitrite and the expression of inducible nitric oxide synthase (iNOS) in airways of asthmatic patients compared to normal control subjects. We also performed a double-blind, crossover randomized-order, placebo-controlled study on 10 asthmatic patients to study the effects of inhaled glucocorticoid treatment (Budesonide) on the formation of peroxynitrite and NO. Fiberoptic bronchial biopsies were examined by immunohistochemistry with antiserum to nitrotyrosine, a marker of protein nitration by peroxynitrite. We also examined the expression of iNOS by immunohistochemistry and in situ hybridization, and measured exhaled NO by chemiluminescence. We correlated the airway production of peroxynitrite with pulmonary functions and airway responsiveness. In airway passages of control subjects, there was weak or no nitrotyrosine immunoreactivity. In contrast, there was strong immunoreactivity for nitrotyrosine in the airway epithelium and inflammatory cells in the airways of persons with asthma. Budesonide treatment resulted in a significant reduction in nitrotyrosine immunoreactivity. Expression of iNOS was evident in the airway pithelium of controls and asthmatic patients, but was significantly more abundant in asthmatic patients. The presence of nitrotyrosine in the airway epithelium (r=-0.841, P<0.0001; r=-0.771, P=0.0004) and inflammatory cells (r=-0.727, P=0014; r=-0.681, P=0.004) correlated inversely with methacholine PC20 and forced expiratory volume in 1 s, respectively. Asthma is associated with increased peroxynitrite formation in the airways, which is reduced after Budesonide treatment. The potent oxidant peroxynitrite may contribute to airway obstruction and hyperresponsiveness and epithelial damage in asthma.

Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD executive summary.

Abstract: Chronic obstructive pulmonary disease (COPD) remains a major public health problem. It is the fourth leading cause of chronic morbidity and mortality in the United States, and is projected to rank fifth in 2020 in burden of disease worldwide, according to a study published by the World Bank/World Health Organization. Yet, COPD remains relatively unknown or ignored by the public as well as public health and government officials. In 1998, in an effort to bring more attention to COPD, its management, and its prevention, a committed group of scientists encouraged the U.S. National Heart, Lung, and Blood Institute and the World Health Organization to form the Global Initiative for Chronic Obstructive Lung Disease (GOLD). Among the important objectives of GOLD are to increase awareness of COPD and to help the millions of people who suffer from this disease and die prematurely of it or its complications. The first step in the GOLD program was to prepare a consensus report, Global Strategy for the Diagnosis, Management, and Prevention of COPD, published in 2001. The present, newly revised document follows the same format as the original consensus report, but has been updated to reflect the many publications on COPD that have appeared. GOLD national leaders, a network of international experts, have initiated investigations of the causes and prevalence of COPD in their countries, and developed innovative approaches for the dissemination and implementation of COPD management guidelines. We appreciate the enormous amount of work the GOLD national leaders have done on behalf of their patients with COPD. Despite the achievements in the 5 years since the GOLD report was originally published, considerable additional work is ahead of us if we are to control this major public health problem. The GOLD initiative will continue to bring COPD to the attention of governments, public health officials, health care workers, and the general public, but a concerted effort by all involved in health care will be necessary.

Health effects of fine particulate air pollution: lines that connect

Abstract: Efforts to understand and mitigate the health effects of particulate matter (PM) air pollution have a rich and interesting history. This review focuses on six substantial lines of research that have been pursued since 1997 that have helped elucidate our understanding about the effects of PM on human health. There has been substantial progress in the evaluation of PM health effects at different time-scales of exposure and in the exploration of the shape of the concentration-response function. There has also been emerging evidence of PM-related cardiovascular health effects and growing knowledge regarding interconnected general pathophysiological pathways that link PM exposure with cardiopulmonary morbidity and mortality. Despite important gaps in scientific knowledge and continued reasons for some skepticism, a comprehensive evaluation of the research findings provides persuasive evidence that exposure to fine particulate air pollution has adverse effects on cardiopulmonary health. Although much of this research has been motivated by environmental public health policy, these results have important scientific, medical, and public health implications that are broader than debates over legally mandated air quality standards.

The human microbiome project.

Abstract: A strategy to understand the microbial components of the human genetic and metabolic landscape and how they contribute to normal physiology and predisposition to disease.