Biomedical subjects

Marina Carini

Publications and source records attributed to Marina Carini.

At least 19 recordsLinked to original sources

PubMed2007

Intervention strategies to inhibit protein carbonylation by lipoxidation-derived reactive carbonyls.

Protein carbonylation induced by reactive carbonyl species (RCS) generated by peroxidation of polyunsaturated fatty acids plays a significant role in the etiology and/or progression of several human diseases, such as cardiovascular (e.g., atherosclerosis, long-term complications of diabetes) and neurodegenerative diseases (e.g., Alzheimer's disease, Parkinson's disease, and cerebral ischemia). Most of the biological effects of intermediate RCS, mainly alpha,beta-unsaturated aldehydes, di-aldehydes, and keto-aldehydes, are due to their capacity to react with the nucleophilic sites of proteins, forming advanced lipoxidation end-products (ALEs). Because of the emerging deleterious role of RCS/protein adducts in several human diseases, different potential therapeutic strategies have been developed in the last few years. This review sheds focus on fundamental studies on lipid-derived RCS generation, their biological effects, and their reactivity with proteins, with particular emphasis to 4-hydroxy-trans-2-nonenal (HNE)-, acrolein (ACR)-, malondialdehyde (MDA)-, and glyoxal (GO)-modified proteins. It also discusses the recently developed pharmacological approaches for the management of chronic diseases in which oxidative stress and RCS formation are massively involved. Inhibition of ALE formation, based on carbonyl-sequestering agents, seems to be the most promising pharmacological tool and is reviewed in detail.

Aldehydes↗

PubMed2006

Electron spin resonance and chemiluminescence analyses to elucidate the vasodilating mechanism of sodium nitroprusside.

The aim of this study was to elucidate the vasodilating mechanism of sodium nitroprusside (SNP). To do this, SNP was intravenously infused in pigs (1.67 micromol/kg), and the following paramagnetic metabolites were identified by electron spin resonance: 1) nitrosylhemoglobin [HbFe(II)NO] as an index of the bioconservative pathway; 2) transferrin; 3) [Fe((II))(CN)(5) NO](3-) and [Fe((II))(CN)(4) NO](2-), the reduced penta- and tetracoordinated intermediates of SNP, respectively; and 4) methemoglobin (met-Hb). The results indicate the following: 1) approximately 17% of the dose is converted to HbFe(II)NO at the end of infusion; 2) NO administered as SNP does not undergo bioinactivation (oxidative metabolism), because no significant increase of met-Hb was observed; 3) the equilibrium involving the paramagnetic species of SNP is shifted toward HbFe(II)NO, because a significant increase of transferrin but no detection of the reduced paramagnetic intermediates of SNP was observed. The results obtained indicate that the hemodynamic effect induced by SNP is not mediated by HbFe(II)NO, at least under physiological conditions; hence, a direct release of NO from SNP in the vascular target should be considered. To demonstrate this mechanism, endothelial cells were incubated with SNP, and the release of NO was determined by a novel chemiluminescence method. The results indicate that the endothelium is able to metabolize SNP, with the formation of stoichiometric amounts of NO. In conclusion, SNP is rapidly metabolized to HbFe(II)NO, but the pharmacological response is mediated by a direct mechanism of NO release of the parent compound at the cellular target.

Animals↗

PubMed2006

Lipoxidation-derived reactive carbonyl species as potential drug targets in preventing protein carbonylation and related cellular dysfunction.

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Aldehydes↗

PubMed2006

Mass spectrometric characterization of covalent modification of human serum albumin by 4-hydroxy-trans-2-nonenal.

Several pieces of evidence indicate that albumin modified by HNE is a promising biomarker of systemic oxidative stress and that HNE-modified albumin may contribute to the immune reactions triggered by lipid peroxidation-derived antigens. In this study, we found by HPLC analysis that HNE is rapidly quenched by human serum albumin (HSA) because of the covalent adduction to the different accessible nucleophilic residues of the protein, as demonstrated by electrospray ionization mass spectrometry (ESI-MS) direct infusion experiments (one to nine HNE adducts, depending on the molar ratio used, from 1:0.25 to 1:5 HSA:HNE). An LC-ESI-MS/MS approach was then applied to enzymatically digested HNE-modified albumin, which permitted the identification of 11 different HNE adducts, 8 Michael adducts (MA) and 3 Schiff bases (SB), involving nine nucleophilic sites, namely: His67 (MA), His146 (MA), His242 (MA), His288 (MA), His510 (MA), Lys 195 (SB), Lys 199 (MA, SB), Lys525 (MA, SB) and Cys34 (MA). The most reactive HNE-adduction site was found to be Cys34 (MA) followed by Lys199, which primarily reacts through the formation of a Schiff base, and His146, giving the corresponding HNE Michael adduct. These albumin modifications are suitable tags of HNE-adducted albumin and could be useful biomarkers of oxidative and carbonylation damage in humans.

Aldehydes↗

PubMed2005

LC-ESI-MS/MS determination of 4-hydroxy-trans-2-nonenal Michael adducts with cysteine and histidine-containing peptides as early markers of oxidative stress in excitable tissues.

A sensitive, selective, specific and rapid liquid chromatographic-electrospray ionization tandem mass spectrometric assay was developed and validated for the simultaneous determination in skeletal muscle of the Michael adducts between 4-hydroxy-trans-2-nonenal (HNE), one of the most reactive lipid peroxidation-driven unsaturated aldehyde, and glutathione (GSH) and the endogenous histidine-containing dipeptides carnosine (CAR) and anserine (ANS), with the final aim to use conjugated adducts as specific and unequivocal markers of lipid peroxidation. Samples (skeletal muscle homogenates from male rats) were prepared by protein precipitation with 1 vol. of a HClO(4) solution (4.2%; w/v) containing H-Tyr-His-OH as internal standard. The supernatant, diluted (1:1, v/v) in mobile phase, was separated on a Phenomenex Sinergy polar-RP column with a mobile phase of water-acetonitrile-heptafluorobutyric acid (9:1:0.01, v/v/v) at a flow rate of 0.2 ml/min, with a run time of 12 min. Detection was on a triple quadrupole mass spectrometer equipped with an ESI interface operating in positive ionization mode. The acquisitions were in multiple reaction monitoring (MRM) mode using the following precursor-->product ion combinations: H-Tyr-His-OH (IS): m/z 319.2--> 156.5+301.6; GS-HNE: m/z 464.3--> 179.1+308.0; CAR-HNE: m/z 383.1--> 110.1+266.6; ANS-HNE: m/z 397.2--> 109.1+126.1. The method was validated over the concentration ranges 1.5-90 (GS-HNE) and 0.4-40 (CAR-HNE, ANS-HNE) nmoles/g wet tissue, and the LLOQ were 1.25 and 0.33 pmoles injected respectively. The intra- and inter-day precisions (CV%) were <7.38% (<or=10.90% at the LLOQs); intra- and inter-assay accuracy (RE%) was within +/-7.0% for all the concentrations (<or=18% at the LLOQs). The method was applied to quantitate peptide-HNE Michael adducts in rat skeletal muscles exposed to oxidative stress to endogenously generate HNE, and the results indicate that CAR-HNE can be considered as an early, specific and stable marker of lipid peroxidation in excitable tissues.

Aldehydes↗

PubMed2005

Carnosine and related dipeptides as quenchers of reactive carbonyl species: from structural studies to therapeutic perspectives.

Carnosine (beta-alanyl-L-histidine) and related peptides such as homocarnosine (gamma-amino-butyryl-histidine), balenine beta-alanyl-L-3-methylhistidine) and anserine beta-alanyl-L-1-methylhistidine) are histidine-containing dipeptides (HD) particularly abundant in excitable tissues such as nervous system and skeletal muscle. Although their biochemical role is still unknown, several evidences indicate that these endogenous compounds act as quenchers of reactive and cytotoxic carbonyl species. In this presentation we will review the structural evidences and ex vivo data supporting this hypothesis. We first elucidated the reaction mechanism of carnosine as quencher of alpha, beta-unsaturated aldehydes such as 4-hydroxy-trans-2,3-nonenal (HNE) and acrolein (ACR) and then demonstrated the efficacy of carnosine and related peptides as detoxifying agents of HNE in spontaneously oxidized rat skeletal muscle, by detecting the corresponding HNE-Michael adducts in the crude biological matrix by liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Finally, we set-up and validated a sensitive, selective and specific LC-ESI-MS/MS method for the determination of HD and of the corresponding HNE-Michael adducts to monitor their profile in physiological (aging) and pathological conditions (diabetes, atherosclerosis) characterized by a carbonyl-mediated degenerative overload. The results obtained, beside to give a contribution to the understanding of the biochemical role of histidine-dipeptides, provide a strong rational to the design of novel derivatives, active as exogenous agents able to detoxify carbonyl compounds.

Acrolein↗

PubMed2005

Covalent modification of actin by 4-hydroxy-trans-2-nonenal (HNE): LC-ESI-MS/MS evidence for Cys374 Michael adduction.

We demonstrate for the first time, by a combined mass spectrometric and computational approach, that G- and F-actin can be covalently modified by the lipid-derived aldehyde, 4-hydroxy-trans-2-nonenal, providing information on the molecular mass of modified protein and the mechanism and site of adduction.ESI-MS analysis of actin treated with different molar ratios of HNE (1 : 1 to 1 : 20) showed the formation of a protein derivative in which there was an increase of 156 Da (42028 Da) over native actin (41872 Da), consistent with the adduction of one HNE residue through Michael addition. To identify the site of HNE adduction, G- and F-actin were stabilized by NaBH(4) reduction and digested with trypsin. LC-ESI-MS/MS analysis in data-dependent scan mode of the resulting peptides unequivocally indicated that Cys374 is the site of HNE adduction. Computational studies showed that the reactivity of Cys374 residue is due to a significant accessible surface and substantial thiol acidity due to the particular microenvironment surrounding Cys374.

Actins↗

PubMed2004

LC-MS/MS and FT-IR analyses of stones from a patient with Crohn's disease: a case report.

This report describes the unusual case of a patient affected by Crohn's disease suffering from intestinal obstruction with recurrent occlusive symptoms not due to the intestinal disease, but to the presence of two calcified foreign bodies in the pelvis. The stones were surgically removed and analysed by reverse-phase liquid chromatography coupled to UV diode array detection and mass spectrometry (LC-UV-DAD-MS/MS), Chromatoprobe-MS/MS and by Fourier-transform-infrared spectroscopy (FT-IR) techniques. The combined mass spectrometric approaches allowed unequivocally to identify 5-aminosalicylic acid (5-ASA) in stone 1, and to demonstrate that its formation was due to an unmodified 5-ASA tablet, a formulation that must undergo complete dissolution in the small bowel. The second stone was constituted by a solid layer (no solvent-extractable material) identified by FT-IR as a polystyrene fragment. This indicates that accidental ingestion of a plastic material, followed by its calcification, was responsible for its formation.

Adult↗

PubMed2004

Nitrosylhemoglobin formation after infusion of NO solutions: ESR studies in pigs.

A saturated nitric oxide (NO) solution (1.88 mM) infused i.v. in the anesthetized pig at a dose of 68 nmol/kg/min for 24 min resulted in a time-dependent increase of nitrosylhemoglobin [HbFe(II)NO] as determined by electron spin resonance (ESR), reaching a C(max) of 7.99 +/- 0.42 microM at the end of the infusion, compared to 1.13 +/- 0.42 microM before (p < 0.01). This indicates that NO i.v. is efficiently bioconserved as HbFe(II)NO (approximately 34% of the NO dose) and to a greater extent than by the oxidative pathway (approximately 24% of the NO dose), as determined by measuring plasma nitrites/nitrates (chemiluminescence) and Met-Hb (ESR analysis). When the NO infusion was stopped, HbFe(II)NO declined with a t(1/2) of 15 min, indicating that it is a stable storage form of NO, able to deliver NO distally to the site of administration. No significant differences were observed in systemic and pulmonary vascular resistances during and after NO infusion, but PO(2) showed a significant decrease 15 and 30 min after the infusion. Thus, in normoxic/physiological conditions, HbFe(II)NO does not induce significant NO-dependent vasorelaxation.

Animals↗

PubMed2004

Nitric oxide release and distribution following oral and intraperitoneal administration of nitroaspirin (NCX 4016) in the rat.

The metabolic fate of nitric oxide (NO) released from nitroaspirin, benzoic acid, 2-(acetyloxy)-3-[(nitrooxy)methyl]phenyl ester (NCX 4016), the lead compound of a new class of NO-releasing non steroidal anti-inflammatory drugs (NO-NSAIDs), has been studied in the rat following p.o. and i.p. administration of 100 mg/kg, by monitoring in plasma the bioactive storage forms of NO (S-nitrosothiols, RS-NO) and its oxidation products (nitrites/nitrates, NOx) by a chemiluminescent assay. In parallel, plasma was analyzed for unchanged drug and metabolites by reverse-phase HPLC. In orally treated rats, no unchanged drug is observed in the 0-24 h interval post-dosing, but only salicylic acid (SA), NOx and RS-NO. The time-course of SA formation parallels that of plasma NOx (plateau after 6 h). Nitrosothiols in plasma are detectable at 1 h, peak at 4 h post-administration, and decline thereafter. The results relative to i.p. administration show a more pronounced and rapid NO delivery (peak of both NOx and RS-NO at 1 h and plateau between 1 and 2 h), still coincident with the peak of SA, and the presence in plasma of NCX 4015 (a metabolite of NCX 4016 which still bears the nitrate function). In myocardial tissue from p.o. treated rats, no drug or metabolites were ever detected, and the NOx levels were always in the range of the controls. Conversely, following i.p. treatment, we observed a rapid compartmentalization within the heart of the unchanged drug, which rapidly disappears in favour of its breakdown products NCX 4015 and SA, with a concomitant rise in myocardial NOx levels up to 2 h. To check the stability of NCX 4016 in the acidic gastric milieu and to explain the different distribution of the drug following p.o. or i.p. administration, the gastric content of the orally-treated animals at different post-dosing times was analysed by HPLC. The unchanged drug was detected up to 8 h post-dosing (levels slowly decreased with time), and the only metabolite to be detected was the O-deacetylated derivative (NCX 4023), which was present in low concentrations up to 4 h post-dosing. This indicates that NCX 4016 does not undergo biotransformation in the upper part of gastrointestinal tract (no direct release of NO in this district) and that the stomach acts as a reservoir for the drug.

Administration, Oral↗

PubMed2004

Chemiluminescence and LC-MS/MS analyses for the study of nitric oxide release and distribution following oral administration of nitroaspirin (NCX 4016) in healthy volunteers.

Administration, Oral↗

PubMed2004

Profiling histidine-containing dipeptides in rat tissues by liquid chromatography/electrospray ionization tandem mass spectrometry.

The histidine-containing dipeptides carnosine (CAR) and structurally related anserine (ANS) and homocarnosine (HCAR), widely distributed in vertebrate organisms, have recently been proposed as endogenous quenchers for highly cytotoxic alpha,beta-unsaturated aldehydes generated by peroxidation. A sensitive, selective, specific and rapid liquid chromatographic/electrospray ionization tandem mass spectrometric assay was developed and validated for the simultaneous determination of these peptides in biological matrices in order to establish their plasma/tissue distribution. Samples (plasma or tissue homogenates from male rats) were prepared by protein precipitation with HClO(4) (1 : 1, v/v) containing H-Tyr-His-OH as internal standard. The supernatant was separated on a Phenomenex Sinergy polar-RP column with a mobile phase of water-acetonitrile-heptafluorobutyric acid (9 : 1 : 0.01, v/v/v) at a flow-rate of 0.2 ml min(-1), with a run time of 10 min. Detection was effected on an ion trap mass spectrometer equipped with an electrospray ionization interface operating in positive ionization mode. The acquisitions were in the multiple reaction monitoring mode using the following precursor --> product ion combinations: H-Tyr-His-OH (internal standard) m/z 319 --> 301; CAR m/z 227 --> 210 + 209; ANS m/z 241 --> 224 + 197 + 170; HCAR m/z 241 --> 156. The method was validated over the concentration range 15-1000 nmol g(-1) and the limit of quantification (LOQ) and limit of detection (LOD) were 12.5 and 4.2 pmol injected, respectively. The intra- and inter-day precisions were <10% (< or =17.47% at the LOQ) and the intra- and inter-assay accuracies were within +/-10% for all concentrations. The mapping profile in rat tissue gave the following results: the highest concentrations of CAR and ANS were found in skeletal muscles (soleus, gastrocnemius, tibialis), followed by the heart, cerebellum and brain (ANS below the LOQ). HCAR was found only in the brain and cerebellum. No histidine-containing dipeptides were detectable in plasma, liver, kidney and lung.

Animals↗

PubMed2004

Iatrogenic ileal obstruction in a patient with Crohn's disease.

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Adult↗

PubMed2003

Procyanidins from grape seeds protect endothelial cells from peroxynitrite damage and enhance endothelium-dependent relaxation in human artery: new evidences for cardio-protection.

The peroxynitrite scavenging ability of Procyanidins from Vitis vinifera L. seeds was studied in homogeneous solution and in human umbilical endothelial cells (EA.hy926 cell line) using 3-morpholinosydnonimine (SIN-1) as peroxynitrite generator. In homogeneous phase procyanidins dose-dependently inhibited 2',7'-dichloro-dihydrofluorescein (DCFH) oxidation induced by SIN-1 with an IC50 value of 0.28 microM. When endothelial cells (EC) were exposed to 5 mM SIN-1, marked morphological alterations indicating a necrotic cell death (cell viability reduced to 16 +/- 2.5%) were observed. Cell damage was suppressed by procyanidins, with a minimal effective concentration of 1 microM (cell morphology and integrity completely recovered at 20 microM). Cellular localization of procyanidins in EC was confirmed using a new staining procedure and site-specific peroxyl radical inducers: AAPH and cumene hydroperoxide (CuOOH). Endothelial cells (EC) pre-incubated with procyanidins (20 microM) and exposed to FeCl3/K3Fe(CN)6 showed a characteristic blue staining, index of a site-specific binding of procyanidins to EC. Procyanidins dose-dependently inhibit the AAPH induced lipid oxidation and reverse the consequent loss of cell viability, but were ineffective when oxidation was driven at intracellular level (CuOOH). This demonstrates that the protective effect is due to their specific binding to the outer surface of EC thus to quench exogenous harmful radicals. Procyanidins dose-dependently relaxed human internal mammary aortic (IMA) rings (with intact endothelium) pre-contracted with norepinephrine (NE), showing a maximal vasorelaxant effect (85 +/- 9%) at 50 microM (catechin: 18 +/- 2% relaxation at 50 microM). This effect was completely abolished when IMA-rings were de-endothelized and when IMA-rings with intact endothelium were pretreated with L-NMMA or with the soluble guanylate cyclase inhibitor, ODQ. Pre-incubation with indomethacin reduces (by almost 50%) the vasodilating effect of procyanidins, indicating the involvement also of a COX-dependent mechanism. This was confirmed in another set of experiments, where procyanidins dose-dependently stimulate the prostacyclin (PGI2) release, reaching a plateau between 25 and 50 microM. Finally, pre-incubation of IMA-rings with procyanidins (from 6.25 to 25 microM) resulted in a dose-dependent prevention of the endothelin-1 (ET-1) vasoconstriction. The ability of procyanidins to prevent peroxynitrite attack to vascular cells, by layering on the surface of coronary EC, and to enhance endothelial NO-synthase-mediated relaxation in IMA rings provide further insight into the molecular mechanisms through which they exert cardioprotective activity in ischemia/reperfusion injury in vivo.

6-Ketoprostaglandin F1 alpha↗

PubMed2003

(-)-Epigallocatechin-3-gallate prevents oxidative damage in both the aqueous and lipid compartments of human plasma.

When human plasma was exposed to the hydrophilic radical initiator, AAPH, (-)-epigallocatechin-(3)-gallate (EGCG) dose-dependently inhibited the aqueous compartment oxidation (IC(50)=0.72 microM) (monitored by DCFH oxidation) and spared the lipophilic antioxidants, alpha-tocopherol, and carotenoids, but not ascorbic acid. When radicals were selectively induced in the lipid compartment by the lipophilic radical initiator, MeO-AMVN, EGCG spared alpha-tocopherol, but not carotenoids and inhibited the lipid compartment oxidation (monitored by BODIPY 581/591) with a potency lower than that found in the aqueous compartment (IC(50)=4.37 microM). Our results indicate that EGCG, mainly localized in the aqueous compartment, effectively quenches aqueous radical species, thus limiting their diffusion into the lipid compartment and preventing lipid-soluble antioxidant depletion. Further, ESR experiments confirmed that EGCG recycled alpha-tocopherol through a H-transfer mechanism at the aqueous/lipid interface affording an additional protective mechanism to the lipid compartment of plasma.

Antioxidants↗

PubMed2003

Acrolein-sequestering ability of endogenous dipeptides: characterization of carnosine and homocarnosine/acrolein adducts by electrospray ionization tandem mass spectrometry.

Acrolein (ACR), the carbonyl toxin produced by lipid peroxidation, is significantly increased in Alzheimer's disease brain. Since ACR is one of the most reactive and neurotoxic aldehydes, and human brain contains both carnosine (beta-alanine-L-histidine) and homocarnosine (gamma-aminobutyryl-L-histidine), the aim of this work was first to evaluate the quenching ability of the two peptides towards ACR and then to characterize their reaction products by electrospray ionization tandem mass spectrometry (ESI-MS/MS; infusion experiments; positive-ion mode). The reaction progress of ACR with carnosine or homocarnosine was studied in phosphate buffer, by monitoring ACR consumption (by reverse-phase LC) and formation of the reaction products by ESI-MS/MS at different incubation times. N-Acetylcarnosine was used as reference compound to identify the sites of reaction. Both the dipeptides were able to quench ACR by almost 60% at 1 h and by more than 85% after 3 h incubation. Different reaction products between ACR and carnosine/homocarnosine were detected after 3 and 24 h, to indicate a complex reaction pathway involving sequential addition of 1, 2 and 3 moles of ACR/mole of the dipeptide to both the beta-alanine and histidine residues. The ESI mass spectra of ACR/carnosine reaction mixtures indicate formation of several molecular species, among which the predominant are: (a) the 14-membered macrocyclic derivatives, deriving from the formation of the iminic bond between the terminal amino group followed by intramolecular Michael addition of the C(3) of the ACR moiety to histidine; (b) the N(beta)-(3-formyl-3,4-dehydropiperidino) derivatives arising from the Michael addition of two acrolein molecules to the amino group of beta-alanine, followed by an aldol condensation and dehydration.The reaction of homocarnosine with ACR follows the same pathway, giving rise to the formation of homologous adducts. The results of this study shed light on the mechanism, until now never demonstrated, through which carnosine and homocarnosine detoxify the highly reactive aldehyde acrolein in a buffer system, and represent the starting point for further studies aimed at elucidating the biological role of these dipeptides in brain.

Acrolein↗

PubMed2003

Detoxification of 4-hydroxynonenal (HNE) in keratinocytes: characterization of conjugated metabolites by liquid chromatography/electrospray ionization tandem mass spectrometry.

Keratinocytes are potential targets of lipid peroxidation products (alpha,beta-unsaturated aldehydes) generated in the skin following UV exposure, among which the most abundant and toxic product is 4-hydroxy-trans-2,3-nonenal (HNE). The aim of this study was to investigate the ability of keratinocytes (NCTC2544 cell lines) to detoxify HNE, through characterization of metabolites, until now never demonstrated, using a combined analytical approach (liquid chromatography (LC) and liquid chromatography/mass spectrometry (LC/MS)). Incubation of cells with HNE (up to 200 micro M) was performed in order to evaluate the ability of the cells to detoxify this toxic aldehyde, and indicated that the cell viability was maintained under these conditions. LC analysis of the extracellular media from keratinocytes incubated with 100 micro M HNE shows a time-dependent decrease of HNE, disappearance from the medium within 2 h and concomitant formation of two unconjugated (phase I) metabolites, 4-hydroxy-2-nonenoic acid (HNA) and 1,4-dihydroxy-2-nonene (DHN), which were both identified and quantified by LC and accounted for 48.8 +/- 4.6% of the HNE dose. Four additional metabolites were identified in the extracellular medium by reversed-phase LC coupled with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) with positive and negative ion detection as Michael adducts (phase II metabolites), arising by the addition of the nucleophilic sulfur of glutathione (GSH) to the electrophilic C-3 of HNE, followed by oxidation-reduction enzymatic processes. The GSH-HNE conjugates were (a) S-(4-hydroxynonanal-3-yl)glutathione, (b) S-(1,4-dihydroxy-nonane-3-yl)glutathione, (c) S-(4-oxononanal-3-yl)glutathione and (d) S-(4-oxo-nonan-1-ol-3-yl)glutathione, and accounted for 52.3 +/- 5.8% of the HNE dose (35 nmol mg(-1) protein), as estimated indirectly by measuring the extent of cellular GSH consumption (18.7 +/- 1.8 nmol mg(-1) protein). The time course of HNE biotransformation was then determined by monitoring the formation of metabolites inside and outside the cell at different times after HNE addition (5-120 min). A time-dependent and almost linear formation inside the cell was observed for all the metabolites (plateau after 15 min of incubation), followed by a rapid decay and a concomitant increase in the extracellular medium (plateau of formation after 60 min). This confirms that HNE diffuses into the cell where is totally metabolized through phase I and phase II reactions to unreactive products, which are then exported outside the cell. This is the first demonstration that skin epidermal cells are able to detoxify the cytotoxic products of lipid peroxidation.

Aldehydes↗

PubMed2003

Effect of a standardized grape seed extract on low-density lipoprotein susceptibility to oxidation in heavy smokers.

The aim of our study was to evaluate the effect of a standardized formulation of a polyphenolic extract of grapes (Leucoselect-Phytosome [LP]) on low-density lipoprotein (LDL) susceptibility to oxidation in a group of heavy smokers. A randomized, double-blind, crossover study was undertaken in 24 healthy male heavy smokers, aged > or = 50 years. Enrolled subjects were given 2 capsules twice daily for 4 weeks (phase 1). Each capsule contained 75 mg of a grape procyanidin extracts and soy-phosphatidlcholine or placebo consisiting of 75 mg lactose and soy-phosphatidlcholine. A wash out period of 3 weeks was then followed by 4 weeks of the opposite treatment (phase 2). Blood samples were taken at baseline and at the end of each phase and assayed for plasma lipids and LDL susceptibility to oxidation. Compliance was good, and no adverse effects were recorded. Subjects did not show significant modification of total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-C) and LDL-C during LP treatment. Among oxidative indices, thiobarbituric acid reactive substances (TBARS) concentration was significantly reduced in subjects taking LP (-14.7% +/- 21.1% v +5.0% +/- 18.1%, P <.01), and the lag phase prolonged (+15.4% +/- 24.4% v -0.1% +/- 16.0%, P <.05) compared with placebo and basal values. The antioxidant potential of grape seed extract polyphenols may prove effective in a model of oxidative stress (smoking); however more investigational data are needed before use in wider clinical settings.

Antioxidants↗