Chromium and human low-density lipoprotein oxidation
| Autor: | Giuliano Ciofani, Domenico Lapenna |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Chromium
Radical chemistry.chemical_element 010501 environmental sciences 01 natural sciences Biochemistry Antioxidants Inorganic Chemistry Metal 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Butylated hydroxytoluene Humans Hexavalent chromium 0105 earth and related environmental sciences Sodium formate Hydrogen-Ion Concentration Lipoproteins LDL chemistry visual_art Low-density lipoprotein visual_art.visual_art_medium Molecular Medicine Hydroxide lipids (amino acids peptides and proteins) Lysosomes Oxidation-Reduction 030217 neurology & neurosurgery Nuclear chemistry |
| Zdroj: | Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS). 59 |
| ISSN: | 1878-3252 |
| Popis: | Chromium is a catalytic metal able to foster oxidant damage, albeit its capacity to induce human LDL oxidation is to date unkown. Thus, we have investigated whether trivalent and hexavalent chromium, namely Cr(III) and Cr(VI), can induce human LDL oxidation. Cr(III) as CrCl3 is incapable of inducing LDL oxidation at pH 7.4 or 4.5. However, Cr(III), specifically at physiological pH of 7.4 and in the presence of phosphates, causes an absorbance increase at 234 resembling a spectrophotometric kinetics of LDL oxidation with a lag- and propagation-like phase. In this regard, it is conceivable that peculiar Cr(III) forms such as Cr(III) hydroxide and, especially, Cr(III) polynuclear hydroxocomplexes formed at pH 7.4 interact with phosphates generating species with an intrinsic absorbance at 234 nm, which increases over time resembling a spectrophotometric kinetics of LDL oxidation. Cr(VI), as K2Cr2O7, can instead induce substantial human LDL oxidation at acidic pH such as 4.5, which is typical of the intracellular lysosomal compartment. LDL oxidation is related to binding of Cr(VI) to LDL particles with quenching of the LDL tryptophan fluorescence, and it is inhibited by the metal chelators EDTA and deferoxamine, as well as by the chain-breaking antioxidants butylated hydroxytoluene and probucol. Moreover, Cr(VI)-induced LDL oxidation is inhibited by mannitol conceivably by binding Cr(V) formed from LDL-dependent Cr(VI) reduction and not by scavenging hydroxyl radicals (OH ); indeed, the OH scavengers sodium formate and ethanol are ineffective against Cr(VI)-induced LDL oxidation. Notably, heightened LDL lipid hydroperoxide levels and decreased LDL tryptophan fluorescence occur in Cr plating workers, indicating Cr-induced human LDL oxidation in vivo. The biochemical, pathophysiological and clinical implications of these novel findings on chromium and human LDL oxidation are discussed. |
| Databáze: | OpenAIRE |
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