Balance in asthma between matrix metalloproteinases and their inhibitors

For decades asthma has been considered a condition of reversible airflow obstruction, and in the majority of patients complete reversibility of long-standing abnormal spirometric measurements such as FEV sub(1) may be observed after treatment. However, many asthmatics, both children and adults, show evidence of residual airway obstruction that may even be detected in asymptomatic patients. This clinically demonstrable irreversible component of airway obstruction was observed on pathologic findings at the turn of the century and was already proposed in the definition of asthma in 1962. However, these features were almost completely ignored for a long time and the concept of airway remodeling in asthma was only proposed in 1992. Remodeling is defined as to "model again or differently, reconstruct." This is a critical aspect of wound repair in all organs, representing a dynamic process that associates matrix production and degradation in reaction to an inflammatory insult leading to a normal reconstruction process (model again) or a pathologic one (model differently).