A multifunctional anti-inflammatory drug that can specifically target activated macrophages, massively deplete intracellular H2O2, and produce large amounts CO for a highly efficient treatment of osteoarthritis

Extensive research during the past 2 decades has revealed the mechanism by which continued oxidative stress can lead to chronic inflammation, which in turn could mediate most chronic diseases including cancer, diabetes, and cardiovascular, neurological, and pulmonary diseases. Oxidative stress can activate a variety of transcription factors including NF-κB, AP-1, p53, HIF-1α, PPAR-γ, β-catenin/Wnt, and Nrf2. Activation of these transcription factors can lead to the expression of over 500 different genes, including those for growth factors, inflammatory cytokines, chemokines, cell cycle regulatory molecules, and anti-inflammatory molecules. How oxidative stress activates inflammatory pathways leading to transformation of a normal cell to tumor cell, tumor cell survival, proliferation, chemoresistance, radioresistance, invasion, angiogenesis, and stem cell survival is the focus of this review. Overall, observations to date suggest that oxidative stress, chronic inflammation, and cancer are closely linked. Copyright © 2010 Elsevier Inc. All rights reserved.

The stress-inducible protein heme oxygenase-1 provides protection against oxidative stress. The anti-inflammatory properties of heme oxygenase-1 may serve as a basis for this cytoprotection. We demonstrate here that carbon monoxide, a by-product of heme catabolism by heme oxygenase, mediates potent anti-inflammatory effects. Both in vivo and in vitro, carbon monoxide at low concentrations differentially and selectively inhibited the expression of lipopolysaccharide-induced pro-inflammatory cytokines tumor necrosis factor-alpha, interleukin-1beta, and macrophage inflammatory protein-1beta and increased the lipopolysaccharide-induced expression of the anti-inflammatory cytokine interleukin-10. Carbon monoxide mediated these anti-inflammatory effects not through a guanylyl cyclase-cGMP or nitric oxide pathway, but instead through a pathway involving the mitogen-activated protein kinases. These data indicate the possibility that carbon monoxide may have an important protective function in inflammatory disease states and thus has potential therapeutic uses.

Carbon monoxide (CO) is increasingly being accepted as a cytoprotective and homeostatic molecule with important signalling capabilities in physiological and pathophysiological situations. The endogenous production of CO occurs through the activity of constitutive (haem oxygenase 2) and inducible (haem oxygenase 1) haem oxygenases, enzymes that are responsible for the catabolism of haem. Through the generation of its products, which in addition to CO includes the bile pigments biliverdin, bilirubin and ferrous iron, the haem oxygenase 1 system also has an obligatory role in the regulation of the stress response and in cell adaptation to injury. This Review provides an overview of the physiology of CO, summarizes the effects of CO gas and CO-releasing molecules in preclinical animal models of cardiovascular disease, inflammatory disorders and organ transplantation, and discusses the development and therapeutic options for the exploitation of this simple gaseous molecule.