Evaluation of the diagnostic potential of some biochemical and molecular markers in early detection of chronic obstructive pulmonary disease

Abstract

COPD is a progressive immunological disorder characterized by three main pathologic phenotypes; chronic bronchitis associated with mucus hyper secretion, chronic obstructive bronchiolitis, in which remodeling and thickening of the airways walls occurs resulting in narrowed or even obstructed lumens and emphysema resulted from loss of the elastic recoil of the lung due to inflammation of the alveoli with destruction of their walls. COPD is presently the fourth leading cause of death worldwide, but WHO predicts that it will become the third leading cause of death by 2030. Risk factors for COPD are still being studied. Occupational and environmental exposures, increased airway responsiveness, exposure to both indoor and outdoor air pollutants and early life exposure to both infectious and noninfectious agents are all risk factors that might play an important role in the development and advancement of COPD but smoking seems to be the major risk factor and the predominant cause of COPD; it is implicated in 90 % of COPD cases. However, only 10–20 % of the smokers develop COPD, pointing to an additional risk factor, such as genetic susceptibility, e.g., the polymorphisms in genes coding for Summary & Conclusion 114 anti-proteases like A1A, MMPs, like MMP-9 or antioxidant enzymes like SOD. SNPs in the genes coding for the two counter acting enzymes; A1A or MMP-9, leading to genetic deficiency of the former enzyme and up-regulation of the later enzyme, accompanied by exposure to other risk factors such as tobacco smoke, facilitate the process of COPD development and progression. The current ‘‘measure’’ of COPD is FEV1. It is both the defining feature of the disease and its measure of severity. FEV1 is the only accepted marker that meets FDA drug approval criteria for COPD, however; COPD is a complex disease with multiple phenotypes that cannot be identified through measurement of lung function alone. In addition; due to the fact that COPD onset is relatively asymptomatic, patients that are at risk or even in the early stages of the disease are not usually monitored by FEV1 measurements, and they got diagnosed when the disease has already progressed. Consequently; there is a considerable need for a reliable and reproducible biomarker that would be specific for early stage of the disease, and also informative for the follow-up of disease progression and development.