Inducible NOS inhibition reverses tobacco-smoke-induced emphysema and pulmonary hypertension in mice

Antioxidant pharmacological therapies for COPD

Increased oxidative stress occurs in the lungs and systemically in COPD, which plays a role in many of the pathogenic mechanisms in COPD. Hence, targeting local lung and systemic oxidative stress with agents that modulate the antioxidants/redox system or boost endogenous antioxidants would be a useful therapeutic approach in COPD. Thiol antioxidants (N-acetyl-l-cysteine [NAC] and N-acystelyn, carbocysteine, erdosteine, and fudosteine) have been used to increase lung thiol content. Modulation of cigarette smoke (CS) induced oxidative stress and its consequent cellular changes have also been reported to be effected by synthetic molecules, such as spin traps (α-phenyl-N-tert-butyl nitrone), catalytic antioxidants (superoxide dismutase [ECSOD] mimetics), porphyrins, and lipid peroxidation and protein carbonylation blockers/inhibitors (edaravone and lazaroids/tirilazad). Preclinical and clinical trials have shown that these antioxidants can reduce oxidative stress, affect redox and glutathione biosynthesis genes, and proinflammatory gene expression. In this review the approaches to enhance lung antioxidants in COPD and the potential beneficial effects of antioxidant therapy on the course of the disease are discussed.

Is iNOS beginning to smoke?

Inducible nitric oxide synthase (iNOS) helps drive numerous inflammatory disorders, but its inhibition has not had therapeutic success. Now Seimetz et al. (2011) make a case for inhibiting iNOS in an effort to treat one of the world's leading causes of death-chronic obstructive pulmonary disease.

Pharmacological antioxidant strategies as therapeutic interventions for COPD

Cigarette/tobacco smoke/biomass fuel-induced oxidative and aldehyde/carbonyl stress are intimately associated with the progression and exacerbation of chronic obstructive pulmonary disease (COPD). Therefore, targeting systemic and local oxidative stress with antioxidants/redox modulating agents, or boosting the endogenous levels of antioxidants are likely to have beneficial effects in the treatment/management of COPD. Various antioxidant agents, such as thiol molecules (glutathione and mucolytic drugs, such as N-acetyl-L-cysteine and N-acystelyn, erdosteine, fudosteine, ergothioneine, and carbocysteine), have been reported to modulate various cellular and biochemical aspects of COPD. These antioxidants have been found to scavenge and detoxify free radicals and oxidants, regulate of glutathione biosynthesis, control nuclear factor-kappaB (NF-kappaB) activation, and hence inhibiting inflammatory gene expression. Synthetic molecules, such as specific spin traps like α-phenyl-N-tert-butyl nitrone, a catalytic antioxidant (ECSOD mimetic), porphyrins (AEOL 10150 and AEOL 10113), and a superoxide dismutase mimetic M40419, iNOS and myeloperoxidase inhibitors, lipid peroxidation inhibitors/blockers edaravone, and lazaroids/tirilazad have also been shown to have beneficial effects by inhibiting cigarette smoke-induced inflammatory responses and other carbonyl/oxidative stress-induced cellular alterations. A variety of oxidants, free radicals, and carbonyls/aldehydes are implicated in the pathogenesis of COPD, it is therefore, possible that therapeutic administration or supplementation of multiple antioxidants and/or boosting the endogenous levels of antioxidants will be beneficial in the treatment of COPD. This review discusses various novel pharmacological approaches adopted to enhance lung antioxidant levels, and various emerging beneficial and/or prophylactic effects of antioxidant therapeutics in halting or intervening the progression of COPD. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.