Leopoldo N. Segal, MD

My interest is to understand the mechanism by which inflammation occurs in Chronic Obstructive Pulmonary Disease (COPD) leading to lung parenchyma destruction and airway remodeling. In the Andre Cournand Pulmonary Physiology Laboratory we can study the distal airway function in patients with early COPD. My focus is on understanding the mechanisms that occur early in the development of this disease where therapeutic approaches might be more efficacious. Although the lung is classically though to be sterile, in COPD increased bacterial colonization leads to airway inflammation and accelerated airway obstruction. The reliance on culture data and contamination by oral flora has limited the ability to understand the effect of airway bacterial load on airway inflammation in early COPD. The study of the microbiome using ribosomal DNA sequence has now opened an opportunity to directly characterize resident microbial flora without the need for bacterial culture. As a pulmonologist, I have sampled the lower airway by bronchoscopy and have exploited recent development next generation rDNA sequence to define complex microbial communities of commensal lung bacteria that we have called a pneumotype. We have found significant bacterial DNA in subjects with early COPD and we evaluate how this pneumotype affects the innate and humoral immunity in the lung of patients with early COPD. By studying how the lung microbiome alters the lung immune response I hope to understand the physiological changes that occurs early in this disease and we may discover new therapeutic targets for patients with obstructive airways disease.