OBJECTIVES: 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), which requires oxidized nicotinamide adenine dinucleotide as a cofactor, metabolizes endogenous glucocorticoids. Since 11beta-HSD2 has been detected in lung epithelial cells, we examined whether carbenoxolone, a potent inhibitor of 11beta-HSD, would enhance endogenous glucocorticoid action on lung fluid balance and inflammation. DESIGN: Controlled laboratory study. SETTING: University research laboratory. SUBJECTS: Adult Sprague-Dawley rats (n = 66). INTERVENTIONS: Rats were intraperitoneally injected with carbenoxolone (2 x 10 mg.kg(-1).day(-1) for 3 days) and allowed free access to water and food. Rats were further challenged with endotoxin instillation (1 mg/kg). MEASUREMENTS AND MAIN RESULTS: We discovered that carbenoxolone significantly increased messenger RNA expression of all three epithelial sodium channel subunits in distal lung tissues (two-fold increase of alpha-subunit, four-fold increase of beta-subunit, and two-fold increase of gamma-subunit) as well as in trachea. Carbenoxolone increased the amiloride-sensitive alveolar fluid clearance significantly. When rats were further challenged by endotoxin instillation (1 mg/kg), pretreatment with carbenoxolone significantly inhibited endotoxin-induced increase in lung neutrophils as well as tumor necrosis factor-alpha and cytokine-induced neutrophil chemoattractant-1 concentrations in serum and bronchoalveolar lavage fluid. CONCLUSIONS: These beneficial effects of carbenoxolone on lung fluid balance and inflammation are very similar to those expected when glucocorticoids are introduced exogenously. We conclude that carbenoxolone increased the actions of endogenous bioactive glucocorticoids on lung cells by reducing local steroid breakdown.
OBJECTIVES: 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), which requires oxidized nicotinamide adenine dinucleotide as a cofactor, metabolizes endogenous glucocorticoids. Since 11beta-HSD2 has been detected in lung epithelial cells, we examined whether carbenoxolone, a potent inhibitor of 11beta-HSD, would enhance endogenous glucocorticoid action on lung fluid balance and inflammation. DESIGN: Controlled laboratory study. SETTING: University research laboratory. SUBJECTS: Adult Sprague-Dawley rats (n = 66). INTERVENTIONS:Rats were intraperitoneally injected with carbenoxolone (2 x 10 mg.kg(-1).day(-1) for 3 days) and allowed free access to water and food. Rats were further challenged with endotoxin instillation (1 mg/kg). MEASUREMENTS AND MAIN RESULTS: We discovered that carbenoxolone significantly increased messenger RNA expression of all three epithelial sodium channel subunits in distal lung tissues (two-fold increase of alpha-subunit, four-fold increase of beta-subunit, and two-fold increase of gamma-subunit) as well as in trachea. Carbenoxolone increased the amiloride-sensitive alveolar fluid clearance significantly. When rats were further challenged by endotoxin instillation (1 mg/kg), pretreatment with carbenoxolone significantly inhibited endotoxin-induced increase in lung neutrophils as well as tumor necrosis factor-alpha and cytokine-induced neutrophil chemoattractant-1 concentrations in serum and bronchoalveolar lavage fluid. CONCLUSIONS: These beneficial effects of carbenoxolone on lung fluid balance and inflammation are very similar to those expected when glucocorticoids are introduced exogenously. We conclude that carbenoxolone increased the actions of endogenous bioactive glucocorticoids on lung cells by reducing local steroid breakdown.
Authors: Tyler J Loftus; Andrew J Thomson; Kolenkode B Kannan; Ines G Alamo; Jessica K Millar; Jessica M Plazas; Elizabeth E Whitley; Philip A Efron; Alicia M Mohr Journal: Am J Surg Date: 2017-06-23 Impact factor: 2.565
Authors: Sandamali A Ekanayaka; Sharon A McClellan; Ronald P Barrett; Shikhil Kharotia; Linda D Hazlett Journal: Invest Ophthalmol Vis Sci Date: 2016-10-01 Impact factor: 4.799