COPD: balancing oxidants and antioxidants

Abstract

Chronic obstructive pulmonary disease (COPD) is one of the most common chronic illnesses in the world. The disease encompasses emphysema, chronic bronchitis, and small airway obstruction and can be caused by environmental exposures, primarily cigarette smoking. Since only a small subset of smokers develop COPD, it is believed that host factors interact with the environment to increase the propensity to develop disease. The major pathogenic factors causing disease include infection and inflammation, protease and antiprotease imbalance, and oxidative stress overwhelming antioxidant defenses. In this review, we will discuss the major environmental and host sources for oxidative stress; discuss how oxidative stress regulates chronic bronchitis; review the latest information on genetic predisposition to COPD, specifically focusing on oxidant/antioxidant imbalance; and review future antioxidant therapeutic options for COPD. The complexity of COPD will necessitate a multi-target therapeutic approach. It is likely that antioxidant supplementation and dietary antioxidants will have a place in these future combination therapies.

Keywords: Chinese herbs; acupuncture; cigarette smoking; dietary antioxidants; gene regulation; mucins.

Figure 1

Schematic depicting the cascade of events underlying the biological effects of cigarette smoking. Note: With exposure to cigarette smoke, there is generation of oxidative stress followed by cell signaling, activation of transcription factors, and release of mediators. Abbreviations: COPD, chronic obstructive pulmonary disease; NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells; Nrf2, nuclear factor erythroid 2-related factor 2.