No abstract

Exposure to cigarette smoke increase the formation of oxidatively modified proteins, lipids, DNA/RNA and carbohydrates in humans. These toxic substances are involved in several pathologies such as, e.g., cancer. Antioxidative supplementation is known to decrease the formation of oxidatively modified proteins, namely, carbonyl proteins. A newly developed combination of 2-oxoglutarate/ascorbic acid/5-hydroxy-methyl-furfur-aldehyde/carnosine was estimated as to the protection of generated carbonyl proteins in vivo and in vitro.Methods: Carbonyl protein content in human plasma of 15 smokers and 15 non-smokers were estimated with the Carbonylprotein ELISA, and in erythrocyte proteins with the spectro-photometically method. 15 smokers were randomly assigned to drink the combination of 2-oxoglutarate/ascorbic acid/5-hydroxy-methylfurfur-aldehyde over 4 weeks. Plasma carbonyl proteins were measured before and after 2 and 4 weeks of supplementation.In vitro studies of cigarette smoke modified proteins in absence or presence of the combination of 2-oxoglutarate/ascorbic acid/5-hydroxy-methyl-furfur-aldehyde/ carnosine or the separate substances 2-oxoglutarate, ascorbic acid, and 5-hydroxy-methyl-furfur-aldehyde were measured with the carbonyl protein spectrophotometically method before, after 2, 15 and 30 minutes.Results: Carbonyl protein in plasma was significantly higher in smokers (448±223 pmol/mg) as compared to non-smokers (191±40 pmol/mg; p<0.02), highly significant in erythrocyte proteins (26.8±12.9 nmol/mg vs. 12.1±0.3 nmol/mg; p<0.001). After 4 weeks the supplemented group showed significant lower carbonyl proteins (228±11 pmol/mg) as compared to the non-supplemented (325±45 pmol/mg; p<0.001).In vitro, smoking of BSA solution showed a significant reduction of generated carbonyl proteins in the presence of the combined supplements after 2 min. (2.18±0.34 nmol/mg vs. 5.94 nmol/mg±0.43 nmol/mg; p<0.001), 15 (2.81±0.31 nmol/mg vs. 7.96±0.79 nmol/mg; p<0.001), 30 min. (3.39±0.32 nmol/mg vs. 9.89 nmol/ mg±0.07 nmol/mg; p<0.001) and 60 min. (3.85±0.63 nmol/mg vs. 11.51 nmol/mg±0.94 nmol/mg; p<0.001) compared to BSA solution without supplements. Using seperate substances at concentrations of 0.106 mM 2-oxo-glutarate showed a significant reduction of carbonyl proteins after 2 min. (48.5%), 15 min. (52.3%), 30 min. (54.6%) and 60 min. (54.7%) incubation with cigarette smoke, vitamin C: 2 min. (41,4%), 15 min. (41.8%), 30 min. (42.7%) and 60 min. (45.0%). 5-HMF: 2 (13.8%), 15 (12.3%), 30 (7.8%) and 60 min. (10.9%). Conclusion:In vivo study in smokers and in vitro studies showed a significant reduction of oxidatively modified proteins in the presence of a combined supplement mixture containing 2-oxoglutarate/ascorbic acid/5-hydroxy-methyl-furfur-aldehyde/carnosine.