Novel steroid-based inhibitors of lung inflammation

Antioxidant activity of lazaroid (U-75412E) and its protective effects against crystalline silica-induced cytotoxicity

Lazaroids (21-amino steroids) are believed to be powerful scavengers of reactive oxygen species (ROS) and inhibitors of lipid peroxidation. Crystalline silica, a potent cytotoxic agent, causes pulmonary fibrosis in experimental animals and humans. ROS have been previously shown to be involved in crystalline silica-induced pulmonary injury and inflammation. In the present study, the reaction rate of lazaroid (U-75412E) with hydroxyl radical (.OH) generated by Fenton reaction (Fe(II) + H2O2 --> Fe(III) + OH- + .OH) was investigated using ESR spin-trapping competition reactions. The reaction rate constant was found to be 1.0 x 10(10) M(-1)s(-1), which was comparable with those of other efficient .OH radical scavengers. As indicators of crystalline silica-induced cytotoxicity and its protection by this antioxidant lazaroid (U-75412E) we measured lactate dehydrogenase, N-acetyl-beta-glucosaminidase, superoxide dismutase, glutathione peroxidase, and hydrogen peroxide released from rat alveolar macrophages. Lipid peroxidation, a prominent manifestation of .OH radical-induced cell injury, was also measured to evaluate the protective value of lazaroid. Alveolar macrophages treated with lazaroid (U-75412E) before crystalline silica exposure were protected against cell injury and lipid peroxidation as demonstrated by those indicators. Lazaroid (U-75412E) scavenges .OH radicals generated by crystalline silica-mediated reaction from H2O2 and inhibits lipid peroxidation in macrophages induced by these particles.

Chronic lung disease of prematurity: are we too cautious with steroids?

Encompassed by the term chronic lung disease (CLD) of prematurity is a sequence of pathophysiological processes ranging from acute inflammation and its resolution to remodelling and growth. There is good evidence for clinical and biological effects of parenteral corticosteroid therapy at each stage in the disease process. A number of questions remain to be resolved: can risk prediction be refined to permit trials of prevention; what is the minimum effective dosage regime; are topical corticosteroids effective; what are the long-term effects on lung growth and development and indeed, is the long-term prognosis of CLD affected by corticosteroid therapy? It is prudent to be cautious with steroids until these questions are answered.