Acidic Derivatization of Thiols Using Diethyl 2-Methylenemalonate: Thiol-Michael Addition Click Reaction for Simultaneous Analysis of Cysteine and Cystine in Culture Media Using LC-MS/MS.

Cysteine (Cys) and its oxidized form, cystine (Cys2), play crucial roles in biological systems and have considerable applications in cell culture. However, Cys in cell culture media is easily oxidized to Cys2, leading to solubility issues. Traditional analytical methods struggle to maintain the oxidation states of Cys and Cys2 during analysis, posing a significant challenge to accurately measuring and controlling these compounds. To effectively control the Cys and Cys2 levels, a rapid and accurate analytical method is required. Here, we screened derivatizing reagents that can react with Cys even under acidic conditions to realize a novel analytical method for simultaneously determining Cys and Cys2 levels. Diethyl 2-methylenemalonate (EMM) was found to possess the desired traits. EMM, characterized by its dual electron-withdrawing attributes, allowed for a rapid reaction with Cys under acidic conditions, preserving intact information for understanding the functions of target compounds. Combined with LC-MS/MS and an internal standard, this method provided high analytical accuracy in a short analytical time of 9 min. Using the developed method, the rapid oxidation of Cys in cell culture media was observed with the headspace of the storage container considerably influencing Cys oxidation and Cys2 precipitation rates. The developed method enabled the direct and simplified analysis of Cys behavior in practical media samples and could be used in formulating new media compositions, ensuring quality assurance, and real-time analysis of Cys and Cys2 in cell culture supernatants. This novel approach holds the potential to further enhance the media performance by enabling the timely optimal addition of Cys.

Exploring the Equilibrium between Glut3SHal and Glut3SH-SO3: A Method for the Quantification of These Compounds in Wine.

3S-Gluthathionylhexanal (glut3SHal) is an early precursor to the important wine aroma compound 3-sulfanylhexan-1-ol (3SH), imparting tropical passion fruit aromas, even at trace concentrations. In wine, glut3SHal occurs in equilibrium with its bisulfite adduct (glut3SH-SO3), challenging its quantification. To circumvent the issues encountered when attempting to describe the equilibrium between these compounds, a method for their quantification in wine samples was developed. Separation of glut3SHal and glut3SH-SO3 using solid-phase extraction followed by oxime derivatization and analysis via liquid chromatography-mass spectrometry allowed for measurement of both compounds in wine samples. Analysis of commercial Sauvignon Blanc wines using the developed method confirmed that glut3SH-SO3 is the major species in the wine matrix. The method developed in this work will enable further exploration of the relationship between glut3SHal and glut3SH-SO3 and their contribution to production of 3SH in wines. There is potential to extrapolate this work to explore other aldehyde-sulfonic acid equilibria in foods and beverages.

Pyrylium-based derivatization for rapid labeling and enhanced detection of thiol in mass spectrometry imaging.

Many endogenous antioxidants, including glutathione (GSH), cysteine (Cys), cysteinyl-glycine (Cys-Gly) and homocysteine (Hcy) possess free thiol functional groups. In most cases, matrix-assisted laser desorption ionization (MALDI) analyses of trace amounts of thiol compounds are challenging because of their instability and poor ionization properties. We present a mass spectrometry imaging (MSI) approach for mapping of thiol compounds on brain tissue sections. Our derivatization reagents 1-(2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)-2,4,6-trimethylpyridinium (MTMP) and 1-(2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)-2,4,5-triphenylpyridinium (MTPP) facilitate the covalent charge-tagging of molecules containing free thiol group for the selective and rapid detection of GSH synthesis and metabolic pathway related metabolites by MALDI-MSI. The developed thiol-specific mass spectrometry imaging method realizes the quantitative detection of exogenous N-acetylcysteine tissue sections, and the detection limit in mass spectrometry imaging could reach 0.05 ng. We illustrate the capabilities of the developed method to mapping of thiol compounds on brain tissue from the chronic social defeat stress (CSDS) depression model mice.

Identification, Quantitation, and Sensory Evaluation of Thiols in Bordeaux Red Wine with Characteristic Aging Bouquet.

Great Bordeaux red wines are known for their distinctive aging bouquet. However, the nature of volatile chemicals underpinning this sensory expression is not fully understood. This work investigated the empyreumatic aging bouquet of a collection of premium Bordeaux red wines using silver-ion (Ag+) solid-phase extraction, cryogenic heart-cutting multidimensional gas chromatography mass spectrometry/olfactometry, and comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. In doing so, a substantial number of "meaty" odors were revealed. Three detected "meaty" notes were tentatively or unequivocally attributed to furan thiols. Among them, 2-methyltetrahydrofuran-3-thiol (1) with a pleasant "meaty" aroma was reported in wine for the first time. Its trans isomer (trans-1a) was resolved from its racemate by chemical modification, which confirmed its presence in wine. The odor detection threshold of trans-1a in the model wine was determined at 55 ng/L. Moreover, an additive effect between 1 and literature-known 2-methyl-3-furanthiol was observed. By a new ultra high-performance liquid chromatography quadrupole Orbitrap high-resolution mass spectrometry method, the concentration of trans-1a, in addition to those of 2-methyl-3-furanthiol and 2-furfuryl thiol, was measured in the wines at ng/L levels.

Portable chemical detection platform for on-site monitoring of odorant levels in natural gas.

The adequate odorization of natural gas is critical to identify gas leaks and to reduce accidents. To ensure odorization, natural gas utility companies collect samples to be processed at core facilities or a trained human technician smells a diluted natural gas sample. In this work, we report a detection platform that addresses the lack of mobile solutions capable of providing quantitative analysis of mercaptans, a class of compounds used to odorize natural gas. Detailed description of the platform hardware and software components is provided. Designed to be portable, the platform hardware facilitates extraction of mercaptans from natural gas, separation of individual mercaptan species, and quantification of odorant concentration, with results reported at point-of-sampling. The software was developed to accommodate skilled users as well as minimally trained operators. Detection and quantification of six commonly used mercaptan compounds (ethyl mercaptan, dimethyl sulfide, n-propylmercaptan, isopropyl mercaptan, tert­butyl mercaptan, and tetrahydrothiophene) at typical odorizing concentrations of 0.1-5 ppm was performed using the device. We demonstrate the potential of this technology to ensure natural gas odorizing concentrations throughout distribution systems.

Hydrogen sulfide production during early yeast fermentation correlates with volatile sulfur compound biogenesis but not thiol release.

Yeasts undergo intensive metabolic changes during the early stages of fermentation. Previous reports suggest the early production of hydrogen sulfide (H2S) is associated with the release of a range of volatile sulfur compounds (VSCs), as well as the production of varietal thiol compounds 3-sulfanylhexan-1-ol (3SH) and 3-sulfanylhexyl acetate (3SHA) from six-carbon precursors, including (E)-hex-2-enal. In this study, we investigated the early H2S potential, VSCs/thiol output, and precursor metabolism of 11 commonly used laboratory and commercial Saccharomyces cerevisiae strains in chemically defined synthetic grape medium (SGM) within 12 h after inoculation. Considerable variability in early H2S potential was observed among the strains surveyed. Chemical profiling suggested that early H2S production correlates with the production of dimethyl disulfide, 2-mercaptoethanol, and diethyl sulfide, but not with 3SH or 3SHA. All strains were capable of metabolizing (E)-hex-2-enal, while the F15 strain showed significantly higher residue at 12 h. Early production of 3SH, but not 3SHA, can be detected in the presence of exogenous (E)-hex-2-enal and H2S. Therefore, the natural variability of early yeast H2S production contributes to the early output of selected VSCs, but the threshold of which is likely not high enough to contribute substantially to free varietal thiols in SGM.

GC-MS Studies on Nitric Oxide Autoxidation and S-Nitrosothiol Hydrolysis to Nitrite in pH-Neutral Aqueous Buffers: Definite Results Using 15N and 18O Isotopes.

Nitrite (O=N-O-, NO2-) and nitrate (O=N(O)-O-, NO3-) are ubiquitous in nature. In aerated aqueous solutions, nitrite is considered the major autoxidation product of nitric oxide (●NO). ●NO is an environmental gas but is also endogenously produced from the amino acid L-arginine by the catalytic action of ●NO synthases. It is considered that the autoxidation of ●NO in aqueous solutions and in O2-containing gas phase proceeds via different neutral (e.g., O=N-O-N=O) and radical (e.g., ONOO●) intermediates. In aqueous buffers, endogenous S-nitrosothiols (thionitrites, RSNO) from thiols (RSH) such as L-cysteine (i.e., S-nitroso-L-cysteine, CysSNO) and cysteine-containing peptides such as glutathione (GSH) (i.e., S-nitrosoglutathione, GSNO) may be formed during the autoxidation of ●NO in the presence of thiols and dioxygen (e.g., GSH + O=N-O-N=O → GSNO + O=N-O- + H+; pKaHONO, 3.24). The reaction products of thionitrites in aerated aqueous solutions may be different from those of ●NO. This work describes in vitro GC-MS studies on the reactions of unlabeled (14NO2-) and labeled nitrite (15NO2-) and RSNO (RS15NO, RS15N18O) performed in pH-neutral aqueous buffers of phosphate or tris(hydroxyethylamine) prepared in unlabeled (H216O) or labeled H2O (H218O). Unlabeled and stable-isotope-labeled nitrite and nitrate species were measured by gas chromatography-mass spectrometry (GC-MS) after derivatization with pentafluorobenzyl bromide and negative-ion chemical ionization. The study provides strong indication for the formation of O=N-O-N=O as an intermediate of ●NO autoxidation in pH-neutral aqueous buffers. In high molar excess, HgCl2 accelerates and increases RSNO hydrolysis to nitrite, thereby incorporating 18O from H218O into the SNO group. In aqueous buffers prepared in H218O, synthetic peroxynitrite (ONOO-) decomposes to nitrite without 18O incorporation, indicating water-independent decomposition of peroxynitrite to nitrite. Use of RS15NO and H218O in combination with GC-MS allows generation of definite results and elucidation of reaction mechanisms of oxidation of ●NO and hydrolysis of RSNO.

Acarbose Mitigates Age-Dependent Alterations in Erythrocyte Membrane Transporters During Aging in Rats.

Acarbose (ACA), a well-studied and effective inhibitor of α-amylase and α-glucosidase, is a postprandial-acting antidiabetic medicine. The membrane of the erythrocyte is an excellent tool for analyzing different physiological and biochemical activities since it experiences a range of metabolic alterations throughout aging. It is uncertain if ACA modulates erythrocyte membrane activities in an age-dependent manner. As a result, the current study was conducted to explore the influence of ACA on age-dependent deteriorated functions of transporters/exchangers, disrupted levels of various biomarkers such as lipid hydroperoxides (LHs), protein carbonyl (PCO), sialic acid (SA), total thiol (-SH), and erythrocyte membrane osmotic fragility. In addition to a concurrent increase in Na+/H+ exchanger activity and concentration of LH, PCO, and osmotic fragility, we also detected a considerable decrease in membrane-linked activities of Ca2+-ATPase (PMCA) and Na+/K+-ATPase (NKA), as well as concentrations of SA and -SH in old-aged rats. The aging-induced impairment of the activities of membrane-bound ATPases and the changed levels of redox biomarkers were shown to be effectively restored by ACA treatment.

Association between flavor composition and sensory profile in thermally processed mandarin juices by multidimensional gas chromatography and multivariate statistical analysis.

Thermal pasteurization decreases the sensory quality of mandarin juice. Flavor composition was determined in four fresh-squeezed and heat-processed mandarin juice varieties using molecular sensory science approaches. The relationships between odorants and sensory profiles were analyzed, and markers for flavor deterioration were screened by multivariate statistical analysis. Seventy-four volatiles were identified, among which 36 odorants with flavor dilution factors ranging from 2 to 128 were detected by multidimensional gas chromatography-mass spectrometry/olfactometry (MDGC-MS/O) coupled with aroma extract dilution analysis (AEDA). Higher intensities of cooked and off-flavor notes were observed in the heated mandarin juice, which was related to the concentration changes of the methional, methanethiol, dimethyl sulfide, and carbon disulfide by partial least squares (PLS) analysis. Ten potential markers (methional, methanethiol, dimethyl sulfide, hydrogen sulfide, ß-damascenone, camphene, trans-ß-ionone, decanal, d-limonene, and α-pinene) were responsible for the sensory discrimination of fresh-squeezed and heated mandarin juices.

A method for the quantitative and reversible trapping of sulfidic gases from headspaces and its application to the study of wine reductive off-odors.

Some relevant food systems release tiny amounts of sulfidic gases, whose measurement is difficult because of their inherent instability. The present paper demonstrates that Cu(I) solutions trap quantitatively and stabilize sulfidic gases. Once trapped, the gases remain stable for weeks at 4 °C and at least 8 days at 75 °C. Trapped gases can be quantitatively released with tris(2-carboxyethyl) phosphine (TCEP) and brine dilution and then determined by GC. Trapping solutions, placed in 20-mL opened vials housed in 100 mL hermetically-sealed flasks containing wine in anoxia, have been used to monitor the release of sulfidic gases by wines, revealing that at 50 °C, up to 400 µg/L of H2S and 58 µg/L of MeSH can be released in 68 days, and 3-5 times more at 75 °C in 28 days. The possibility to differentiate between released and accumulated amounts provides key clues to understanding the fate of sulfidic gases in wine and other food systems.

Visual and quantitative monitoring of thiophenol by a novel deep-red emitting fluorescent probe in environmental and biological systems.

Detection of highly toxic thiophenols in biological or environmental systems is of great importance. Therefore, fast, reliable, and sensitive probes are needed to detect thiophenols. Herein, a novel triphenylamine conjugated dicyanoisophorone-based near infrared fluorescence probe is reported to determine trace thiophenol (PhSH) levels. The probe demonstrates a distinct "turn-on" fluorescence response to thiophenol among the tested analytes and its quantum yield (Φ) increases from 0.011 to 0.142. It has low cytotoxicity with cell viability of 90-100% up to 10.0 µM of the probe, a strong anti-interference capability, a large Stokes shift (150 nm), and a fast response time (<1 min). In addition, the probe exhibits a good linear response to PhSH over the range from 0 to 15.0 µM with a detection limit of 32.3 nM (R2 = 0.9978). The detection process is also confirmed through HPLC. The practical applicability of the probe is proved by a smartphone platform, TLC kit, plant tissue imaging, soil assay, tap, and lake water analysis with good recovery values (92.3-117%), and concentration-dependent live cell bioimaging PhSH from 5.0 to 15.0 µM. Therefore, the present probe is a robust candidate for monitoring PhSH levels in biological and environmental systems.

Engineering volatile thiol formation in yeast.

AIMS: Volatile thiols are very potent aroma molecules that contribute to the aroma of many beverages. The characteristic thiols of certain wine varieties such as Sauvignon blanc are partly released during the yeast-based fermentation from plant-synthesized glutathione- or cysteine-conjugated and dipeptic precursors present in the must. In this work, we aimed at the construction and characterization of yeast strains with the ability to synthesize volatile thiols from respective precursors. METHODS AND RESULTS: Besides genome integration of the Escherichia coli gene tnaA, which encodes an enzyme with high ß-lyase activity, a glutathione synthetase and glutathione-S-transferases were overexpressed. Up to 8.9 µg L-1 3-mercaptohexan-1-ol could be formed with the strain from externally added trans-2-hexen-1-ol. Well-characterized thiols such as 2-methyl-2-butanethiol, 3-mercapto-3-methylbutan-1-ol, and 8-mercapto-p-menthan-3-one, as well as several so far undescribed thiol compounds could be synthesized. CONCLUSION: Volatile thiols could be produced by feeding alcohol, alkenol, aldehyde, or ketone precursors like trans-2-hexenal, trans-2-hexen-1-ol, cis-2-hexen-1-ol, 3-methyl-2-buten-1-ol, 3-buten-2-one, and pulegone to the optimized yeast cells.

Impact of accentuated cut edges, yeast strain, and malolactic fermentation on chemical and sensory profiles of Sauvignon blanc wine.

This pioneering investigation involved the application of accentuated cut edges (ACE) technique to Sauvignon blanc winemaking. The concentration of varietal thiol precursors in juice was significantly higher for ACE treatment compared to conventional crushing, with two-way or three-way interactions of the experimental factors, which included yeast strain and malolactic fermentation, being determined from the wine data. ACE yielded higher concentrations of 4-methyl-4-sulfanylpentan-2-one (4-MSP) and enantiomers of 3-sulfanylhexanol (3-SH) and 3-sulfanylhexyl acetate (3-SHA) in wines that were more abundant in phenolic compounds. Compared to Sauvy yeast strain, VIN13 produced greater amounts of 3-SH and 3-SHA but less 4-MSP with wines exhibiting lower intensity 'floral' and 'fruity' notes. MLF increased 3-SH and 4-MSP concentrations and led to wines that exhibited more non-fruity sensory attributes. The study revealed the potential of ACE for increasing varietal thiol concentrations in Sauvignon blanc wine and altering overall sensory profiles, with interactions involving yeast strain and MLF.

Ru(bpy)32+ as a photoinduced oxidase mimic for colorimetric detection of biothiols.

We have found that tris (2,2'-bipyridyl) ruthenium (II) (Ru(bpy)32+) possesses a high photo-induced oxidase-like activity and is capable of catalyzing the color reaction of 3,3',5,5'-tetramethylbenzidine (TMB) with dissolved oxygen. Ru(bpy)32+ has a catalytic constant (Kcat) that is twice as high as that of fluorescein, 170 and 275-fold higher than that of 9-mesityl-10-methyl acridine and Eosin Y, respectively. Electron spin resonance spectroscopy (ESR) and radical scavenging experiments have verified the major active radicals involved in the color reaction are •OH. A colorimetric biothiol assay has been successfully developed for the oxidase-like activity of Ru(bpy)32+ can be suppressed by sulfhydryl compounds. A linear dependence between the decrease in absorbance and the logarithm of thiol concentrations can be found ranging from 5.0 to 50 µM, with a detection limit of 1.0 µM. This work reveals a new oxidase mimic with high catalytic activity and will facilitate the utilization of this oxidase mimic in biochemical analysis.

Endogenous benzoic acid interferes with the signatures of amino acids and thiol compounds through perturbing N-methyltransferase, glutamate-cysteine ligase, and glutathione S-transferase activity in dairy products.

Endogenous benzoic acid causes adverse effects on individual health, but the potential mechanisms often remain elusive. The positive rate of benzoic acid in seventy-two goat milk samples in triplicate was 93.6 %, verifying the presence of endogenous benzoic acid. In this study, we investigated the differences in protein expression and metabolites among goat milk with different final concentrations of benzoic acid via combined proteomics and metabolomics (LOQ 3.25 to 56.63 µg L-1) analysis based on UHPLC-Q-Orbitrap HRMS. Integrated analysis showed that benzoic acid reduced the content of l-histidine (from 1.27 to 0.49 mg/L) and 1-methylhistidine (from 1.40 to 0.68 mg/L), due to the increase of benzoic acid (0-30 mg/L) concentration significantly reduced the level and activity of N-methyltransferase. Protein-metabolite interactions suggested that benzoic acid enhanced glutamate-cysteine ligase and glutathione S-transferase expression and affected l-glutamate (from 1.22 to 0.49 mg/L) and glutathione contents, eventually leading to the formation of off-flavors and oxidation of goat milk. Meanwhile, the level of l-phenylalanine (from 4.17 to 1.94 mg/L) and l-tyrosine (from 1.05 to 0.26 mg/L) progressively decreased with the increase of benzoic acid concentration, which had a deleterious effect on the nutritional value and flavor formation of goat milk. These findings clarified the mechanism by which low-dose benzoic acid negatively affects the nutritional quality and flavor formation of goat milk.

[Temporal and Spatial Variation in Odor Pollution and Membrane Barrier Effect in Municipal Solid Waste Landfill].

In order to explore the source characteristics as well as the temporal and spatial variations in odor pollution in municipal waste landfills, gas samples were collected from a landfill in an eastern coastal area of China throughout winter and summer. The total concentration of malodorous substances reached 60000 µg·m-3. There were more types of odor pollutants detected in summer than in winter, the average concentration was 30-300 times higher than that in winter, and the concentration of sulfur compounds increased by 4.7-136.7 times in summer. Oxygenated compounds had the highest concentration, and the total concentration of sulfur compounds accounted for less than 10% of malodorous substances. However, sulfur compounds contributed more than 90% to the theoretical odor concentration. Sulfur compounds such as methyl mercaptan and propane mercaptan were the key odorants in the landfill. After the landfill unit was covered, the concentration of odorous substances and the theoretical odor concentration on the surface of the landfill showed an increasing trend with time, indicating that the covering had a certain odor barrier effect; however, the landfill unit still had a large odor release potential. The similarity analysis showed that the odorous gas accumulated in the unit with temporary cover and without an exhaust system could be released to the environment through the overlapping gap of the membrane and the location of membrane rupture, resulting in more serious odor pollution around the landfill at night than that during the day.

The association of maternal dietary quality and the antioxidant-proxidant balance of human milk.

BACKGROUND: Human milk composition varies over time within an individual mother as well as between lactating mothers due to several factors including maternal health, diet, and nutritional status. Therefore, improving nutrition status during gestation and breastfeeding is crucial for improving the health of both mothers and infants. Diet can enhance the oxidant-antioxidant balance of human milk. This study aimed to investigate the association between human milk oxidant-antioxidant balance with dietary patterns of lactating mothers identified by using principal component analysis. METHOD: This cross-sectional study included 350 breastfeeding women between the ages of 20 to 35 years. The dietary intakes of the women in the study were estimated using a validated food frequency questionnaire, which included 65 food items. The oxidant-antioxidant balance of milk samples was assessed using the ferric reducing antioxidant power (FRAP), 2, 2'-diphenyl-1-picrylhydrazyl (DPPH), thiobarbituric acid reactive substances (TBARs), and Ellman's assay. The milk concentration of total protein, calcium, and triglyceride was also measured using commercial kits. RESULT: Two predominant dietary patterns were recognized that we defined as a healthy and unhealthy pattern. There were higher levels of DPPH and thiol in the milk from mothers in the third tertile (highest adherence) of a healthy dietary pattern compared to the first tertile (lowest adherence; p < 0.05). Milk calcium and thiol were significantly lower in the third tertile of mothers with an unhealthy dietary pattern versus the first tertile (P < 0.05). In multivariate multinomial logistic regression analyses adjusted for mother's age, body mass index (BMI), energy intake, and infant's sex, adherence to a healthy dietary pattern was associated with higher levels of milk DPPH (OR = 1.32, 95% confidence interval (CI): 1.01, 1.80) and milk thiol (OR = 1.21, 95% CI: 1.10, 1.50). On the other adherence to the unhealthy dietary pattern was correlated with low levels of milk thiol (OR = 1.29; 95%CI: 1.09, 1.59) and milk calcium (OR = 1.28; 95%CI: 1.11, 1.55). CONCLUSION: Our findings demonstrated that adherence to a healthy dietary pattern, identified by higher consumption of green vegetables, other vegetables, and fruits is associated with a higher milk oxidant-antioxidant status in breastfeeding mothers.

Analysis of volatile organic compounds from deep airway in the lung through intubation sampling.

Exhaled volatile organic compounds (VOCs) have been widely applied for the study of disease biomarkers. Oral exhalation and nasal exhalation are two of the most common sampling methods. However, VOCs released from food residues and bacteria in the mouth or upper respiratory tract were also sampled and usually mistaken as that produced from body metabolism. In this study, exhalation from deep airway was first directly collected through intubation sampling and analyzed. The exhalation samples of 35 subjects were collected through a catheter, which was inserted into the trachea or bronchus through the mouth and upper respiratory tract. Then, the VOCs in these samples were detected by proton transfer reaction mass spectrometry (PTR-MS). In addition, fast gas chromatography proton transfer reaction mass spectrometry (FGC-PTR-MS) was used to further determine the VOCs with the same mass-to-charge ratios. The results showed that there was methanol, acetonitrile, ethanol, methyl mercaptan, acetone, isoprene, and phenol in the deep airway. Compared with that in oral exhalation, ethanol, methyl mercaptan, and phenol had lower concentrations. In detail, the median concentrations of ethanol, methyl mercaptan, and phenol were 7.3, 0.6, and 23.9 ppbv, while those in the oral exhalation were 80.0, 5.1, and 71.3 ppbv, respectively, which meant the three VOCs mainly originated from the food residues and bacteria in the mouth or upper respiratory tract, rather than body metabolism. The research results in our study can provide references for expiratory VOC research based on oral and nasal exhalation samplings, which are more feasible in clinical practice.

Oxidative stress in maternal milk and cord blood in gestational diabetes mellitus: a prospective study

ABSTRACT BACKGROUND: Reduced antioxidant defenses may reflect a poor protective response against oxidative stress and this may be implicated in progression of gestational diabetes mellitus (GDM). Oxidative stress induced by hyperglycemia plays a major role in micro and macrovascular complications, which imply endothelial dysfunction. OBJECTIVE: Our aim in this study was to investigate the association between GDM and oxidative stress markers measured in plasma, with regard to revealing changes to total antioxidant capacity (TAC) and total oxidant status (TOS) among mothers showing impairments in oral glucose tolerance tests (OGTTs). DESIGN AND SETTING: Prospective study at a university hospital in Turkey. METHODS: The study group consisted of 50 mothers with GDM, and 59 healthy mothers served as controls. Umbilical cord blood samples were taken from all mothers during delivery and breast milk samples on the fifth day after delivery. TAC, TOS, thiol and disulfide levels were measured. RESULTS: No statistically significant relationship between the blood and milk samples could be found. An analysis on correlations between TAC, TOS and certain parameters revealed that there were negative correlations between TOS and total thiol (r = -0.386; P < 0.001) and between TOS and disulfide (r = -0.388; P < 0.001) in milk in the control group. However, these findings were not observed in the study group. CONCLUSION: Our findings suggested that a compensatory mechanism of oxidative stress was expected to be present in gestational diabetes mellitus and that this might be ameliorated through good glycemic regulation and antioxidant supplementation.

Oxidative stress in maternal milk and cord blood in gestational diabetes mellitus: a prospective study.

BACKGROUND: Reduced antioxidant defenses may reflect a poor protective response against oxidative stress and this may be implicated in progression of gestational diabetes mellitus (GDM). Oxidative stress induced by hyperglycemia plays a major role in micro and macrovascular complications, which imply endothelial dysfunction. OBJECTIVE: Our aim in this study was to investigate the association between GDM and oxidative stress markers measured in plasma, with regard to revealing changes to total antioxidant capacity (TAC) and total oxidant status (TOS) among mothers showing impairments in oral glucose tolerance tests (OGTTs). DESIGN AND SETTING: Prospective study at a university hospital in Turkey. METHODS: The study group consisted of 50 mothers with GDM, and 59 healthy mothers served as controls. Umbilical cord blood samples were taken from all mothers during delivery and breast milk samples on the fifth day after delivery. TAC, TOS, thiol and disulfide levels were measured. RESULTS: No statistically significant relationship between the blood and milk samples could be found. An analysis on correlations between TAC, TOS and certain parameters revealed that there were negative correlations between TOS and total thiol (r = -0.386; P < 0.001) and between TOS and disulfide (r = -0.388; P < 0.001) in milk in the control group. However, these findings were not observed in the study group. CONCLUSION: Our findings suggested that a compensatory mechanism of oxidative stress was expected to be present in gestational diabetes mellitus and that this might be ameliorated through good glycemic regulation and antioxidant supplementation.