The influence of selenium and vitamin E on the enhanced respiratory burst reaction in smokers

Oxidative stress in asthma and COPD: antioxidants as a therapeutic strategy

Asthma and chronic obstructive pulmonary disease (COPD) are inflammatory lung diseases that are characterized by systemic and chronic localized inflammation and oxidative stress. Sources of oxidative stress arise from the increased burden of inhaled oxidants, as well as elevated amounts of reactive oxygen species (ROS) released from inflammatory cells. Increased levels of ROS, either directly or via the formation of lipid peroxidation products, may play a role in enhancing the inflammatory response in both asthma and COPD. Moreover, in COPD it is now recognized as the main pathogenic factor for driving disease progression and increasing severity. ROS and lipid peroxidation products can influence the inflammatory response at many levels through its impact on signal transduction mechanisms, activation of redox-sensitive transcriptions factors, and chromatin regulation resulting in pro-inflammatory gene expression. It is this impact of ROS on chromatin regulation by reducing the activity of the transcriptional co-repressor, histone deacetylase-2 (HDAC-2), that leads to the poor efficacy of corticosteroids in COPD, severe asthma, and smoking asthmatics. Thus, the presence of oxidative stress has important consequences for the pathogenesis, severity, and treatment of asthma and COPD. However, for ROS to have such an impact, it must first overcome a variety of antioxidant defenses. It is likely, therefore, that a combination of antioxidants may be effective in the treatment of asthma and COPD. Various approaches to enhance the lung antioxidant screen and clinical trials of antioxidant compounds are discussed.

Thioredoxin reductase is one of the selenoproteins in both promyelocytic and granulocytic HL-60 cells

Human leukemia promyelocytic HL-60 cells differentiate into granulocytes when cultured with 1.25% dimethyl sulfoxide for 3 d. The radioactive Na2 75SeO3 incorporation and the amount of total proteins were interrelated in both promyelocytic and granulocytic HL-60. Promyelocytic cells had four times higher 75Se incorporation and 34% more protein synthesis than the granulocytic cells on the fifth culturing day. The enzyme activities of glutathione peroxidase (GSH-Px, E.C. 1.11.1.9) and thioredoxin reductase (TrxR, E.C. 1.6.4.5) in both types of cells increased significantly and approached steady stage on the third day. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) analysis and autoradiography of the proteins from the cells revealed three proteins with molecular weights of 57, 28, and 21 kDa, respectively. These three 75Se-labeled proteins were present in both types of cells. The proteins from HL-60 cells were separated by DEAE-Sepharose and 2'5'-ADP-Sepharose columns. The purified 57-kDa protein had TrxR activity of 0.744 micromol 5'-thionitrobenzoic acid (TNB) formed/min/mg protein and two isoelectric points at pH 5.9 and 6.0. These results suggest that TrxR is one of the selenoproteins in both promyelocytic and granulocytic HL-60 cells.

Fish oil may be an antidote for the cardiovascular risk of smoking

The fact that the cardiovascular risk of ex-smokers approximates that of non-smokers after two years of abstinence, implies that accelerated atherogenesis is not the chief mechanism of smoking-related heart disease. Indeed, smoking or nicotine have adverse effects on blood rheology, thrombotic risk, coronary blood flow, and risk for arrhythmias. Omega-3-rich fish oils can be expected to correct or compensate for a remarkable number of the adverse impacts of smoking/nicotine: increased plasma fibrinogen, decreased erythrocyte distensibility, increased plasma and blood viscosity, increased platelet aggregability, increased plasminogen activator inhibitor levels, vasoconstriction of the coronary bed, reduced fibrillation threshold, increased triglycerides, reduced high-density lipoprotein cholesterol, and increased production of superoxide by phagocytes. Smokers who cannot overcome their addiction should be encouraged to substitute nicotine aerosols/gum for tobacco and advised to use supplementary fish oil and other cardioprotective nutrients.