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| Author(s): |
Émersom Silva Lima
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2003-12-09 |
| Examining board members: |
Dulcineia Saes Parra Abdalla;
Paolo Di Mascio;
Marta Helena Krieger;
Francisco Rafael Martins Laurindo;
Marcelo Ganzarolli de Oliveira
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| Advisor: | Dulcineia Saes Parra Abdalla |
| Abstract | |
Nitric oxide (•NO) and •NO-derived reactive species react with lipidic radicals to generate nitrated species. Several in vitro studies have described nitrated lipid-derived products. However, the presence of the nitrated lipids in human biological samples has not been demonstrated yet. Herein, we report the synthesis, purification, characterization, bioactivity of •NO release and detection of nitrated derivatives of the linoleic acid (LNO2) linoleic acid hydroperoxide (LNO2OH) and cholesteryl linoleate (ChLNO2) in human blood plasma and lipoproteins using a high-pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry method (LC-ESI/MS/MS). The nitrated products were synthesized in vitro, purified by column liquid chromatography or thin liquid chromatography before characterization analyses. •NO release analyses was performed using quimiluminescence, electron paramagnetic resonance analysis of NO-spin trap complex (Fe-MGD2, Carboxy-PTIO, DBNBS) and by induction effect of endothelium-independent relaxation in rat aortic rings. Stable products, showing the same chromatographic characteristics and fragmentation pattern as those LNO2, LNO2OH and ChLNO2 synthesized standards, were found in human blood plasma and lipoproteins of normolipidemic and hyperlipidemic subjects. The synthesized standards released •NO spontaneously, which was enhancing by ascorbate and inhibited by hemoglobin and carboxy-PTIO, besides to relax the rat aortic rings. The presence of this novel nitrogen-containing lipid adduct was by the first time detected in human biological samples. It may represent a potential antioxidant role that •NO or its metabolites play during in vivo lipid oxidation, through the generation of a probably protection compensatory mechanism against the nitrative/oxidative stress found in the hyperlipidemia. (AU) | |