GC × GC-TOFMS metabolomics analysis identifies elevated levels of plasma sugars and sugar alcohols in diabetic mellitus patients with kidney failure.

Two dimensional GC (GC × GC)-time-of-flight mass spectrometry (TOFMS) has been used to improve accurate metabolite identification in the chemical industry, but this method has not been applied as readily in biomedical research. Here, we evaluated and validated the performance of high resolution GC × GC-TOFMS against that of GC-TOFMS for metabolomics analysis of two different plasma matrices, from healthy controls (CON) and diabetes mellitus (DM) patients with kidney failure (DM with KF). We found GC × GC-TOFMS outperformed traditional GC-TOFMS in terms of separation performance and metabolite coverage. Several metabolites from both the CON and DM with KF matrices, such as carbohydrates and carbohydrate-conjugate metabolites, were exclusively detected using GC × GC-TOFMS. Additionally, we applied this method to characterize significant metabolites in the DM with KF group, with focused analysis of four metabolite groups: sugars, sugar alcohols, amino acids, and free fatty acids. Our plasma metabolomics results revealed 35 significant metabolites (12 unique and 23 concentration-dependent metabolites) in the DM with KF group, as compared with those in the CON and DM groups (N = 20 for each group). Interestingly, we determined 17 of the 35 (14/17 verified with reference standards) significant metabolites identified from both the analyses were metabolites from the sugar and sugar alcohol groups, with significantly higher concentrations in the DM with KF group than in the CON and DM groups. Enrichment analysis of these 14 metabolites also revealed that alterations in galactose metabolism and the polyol pathway are related to DM with KF. Overall, our application of GC × GC-TOFMS identified key metabolites in complex plasma matrices.

Effects of Continuous Albuterol Inhalation on Serum Metabolome in Healthy Subjects: More Than Just Lactic Acid.

Treatment with ß2-agonists may cause elevated lactic acid, the end product of anaerobic metabolism of glucose. It has been proposed that lactic acidosis associated with ß2-agonists is caused by changes to direct biochemical impacts on glycolysis, gluconeogenesis, pyruvate metabolism, and free fatty acid production. However, much remains unknown, and there is a paucity of evidence regarding the underlying chemical changes associated with this lactic acidosis. The goal of our study was to investigate the impact of 1 hour of continuous albuterol on the untargeted serum metabolome of healthy subjects. Twenty-four healthy participants received 7.5 mg of continuous albuterol for 1 hour. Baseline, 1-hour, and 2-hour lactic acid levels were drawn. Samples obtained at baseline and 1 hour were sent for untargeted metabolomic profiling. Participants had a baseline lactic acid of 1.45 ± 0.46 mmol/L. On average, lactate levels increased 0.33 ± 0.67 mmol/L after 1 hour (P = .02) and remained elevated at 2 hours (0.32 ± 0.72 mmol/L, P = .02), although there was overlap in lactate levels across times. For metabolomic analysis, fatty acids, organic acids, and sugars were elevated, and amino acids were reduced. Lactic acid and pyruvic acid metabolites, however, did not significantly change (after false discovery rate adjustment). In healthy participants, continuous albuterol alters the serum metabolome, but this change may not be clinically significant. The data support recent hypotheses that ß2-receptor activation stimulates lactic acid production, altering aerobic glycolysis, gluconeogenesis, and free fatty acid production.

Diabetes Mellitus and Hypertension-A Case of Sugar and Salt?

The majority of patients with diabetes mellitus (DM) have hypertension (HTN). A specific mechanism for the development of HTN in DM has not been described. In the Zucker, Endothel, und Salz (sugar, endothelium, and salt) study (ZEuS), indices of glucose metabolism and of volume regulation are recorded. An analysis of these parameters shows that glucose concentrations interfere with plasma osmolality and that changes in glycemic control have a significant impact on fluid status and blood pressure. The results of this study are discussed against the background of the striking similarities between the regulation of sugar and salt blood concentrations, introducing the view that DM is probably a sodium-retention disorder that leads to a state of hypervolemia.

Exploring the Diversity of Sugar Compounds in Healthy, Prediabetic, and Diabetic Volunteers.

SCOPE: Diabetes is thought to primarily represent a disturbance of carbohydrate metabolism; however, population studies employing metabolomics have mainly identified plasma amino acids and lipids, or their products, as biomarkers. In this pilot study, the aim is to analyze a wide spectrum of sugar compounds in the fasting state and during an oral glucose tolerance test (OGTT) in healthy, prediabetic, and type 2 diabetic volunteers. METHODS AND RESULTS: The three volunteer groups underwent a standard OGTT. Plasma samples obtained in the fasting state, 30 and 90 min after the OGTT, are subjected to a semitargeted GC-MS (gas chromatography-mass spectrometry) sugar profiling. Overall, 40 sugars are detected in plasma, of which some are yet unknown to change during an OGTT. Several sugars (e.g., trehalose) reveal significant differences between the volunteer groups both in fasting plasma and in distinct time courses after the OGTT. This suggests an endogenous production from orally absorbed glucose and/or an insulin-dependent production/removal from plasma. CONCLUSION: It is demonstrated that more sugars than expected can be found in human plasma. Since some of these show characteristic differences depending on health status, it may be worthwhile to assess their usability as biomarkers for diagnosing early-stage insulin resistance and type 2 diabetes.

Non-invasive and Time-dependent Blood-sugar Monitoring via Breath-derived CO2 Correlation Using Gas Chromatograph with a Milli-whistle Gas Analyzer.

A clear and positive correlation between the CO2 concentration and the blood-sugar level has been observed via a non-invasive and time-dependent monitoring of CO2 concentration from human breath, which is carried out by using a home-made gas chromatography (GC)/milli-whistle compact analyzer. The time-dependent sampling of the CO2 concentration correlated between 5.0 to 5.6% (1% = 104 ppm) in accordance with blood-sugar level variations of 80 to 110 mg/dL. The analytical method results in a rapid, continuous and non-invasive determination of blood-sugar level via measurement of the CO2 concentration exhaled from the lungs.

Untargeted Metabonomics of Genetically Modified Cows Expressing Lactoferrin Based on Serum and Milk.

Metabolites of serum and milk from genetically modified (GM) cows and contrast check (CK) cows were comparatively investigated. Serum and milk were collected from genetically modified (GM) cows and contrast check (CK) cows, and then, they were analyzed using ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) and gas chromatography-mass spectrometry (GC-MS). Although the level of some blood biochemical indexes for GM cows was shifted up or down, they were generally in normal physiological condition. Serum samples from lactoferrin GM cows exhibited reduced levels of amino acids and elevated levels of indoleacetate, α-keto acids, long-chain fatty acids, etc. GM milk possessed elevated levels of pentose and amino sugar metabolites, including arabitol, xylulose, glucuronate, and N-acetylgalactosamine. Interestingly, some essential nutrients, such as certain unsaturated fatty acids (e.g., eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and docosapentaenoic acid (DPA)), and some necessary rare sugars were significantly upregulated. Compared to the CK group, a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was conducted based on the increased or decreased metabolites identified in the serum and milk samples of the GM group. The results showed that the GM cows were in healthy condition and their milk has improved benefits for customers. The milk from genetically modified cows was found to be a promising milk source for producing recombinant human lactoferrin (rhLF) for human beings.

Preparation and characterization of D. opposita Thunb polysaccharide-zinc inclusion complex and evaluation of anti-diabetic activities.

In the present work, Dioscorea opposita Thunb polysaccharide-zinc (DPS-zinc) inclusion complex was synthesized for the first time and its anti-diabetes activities against Streptozotocin (STZ)-induced diabetic rats were assayed. The detail structural and morphological analysis of as-prepared DPS-zinc complex was done by using different spectroscopic and microscopic methods. The pharmacological study revealed that DPS-zinc presented a potent hypoglycemic effect on STZ-induced diabetic rats, decreased the glucose and insulin levels, reduced malondialdehyde (MDA) contents and increased SOD and T-AOC activities significantly in liver. The levels of T-CHO, TG and LDL-C in serum were dramatically decreased while HDL-C level was increased with the treatment of proposed inclusion complex. In brief, DPS-zinc could be considered as a potential candidate for developing an ingredient of functional foods for zinc supplements with the hypoglycemic action.

Tuning the surface of Au nanoparticles using poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol): enzyme free and label free sugar sensing in serum samples using resonance Rayleigh scattering spectroscopy.

Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (F-108) functionalized gold nanoparticles (Au NPs) have been successfully synthesized. During synthesis it is found that an increase in the F-108 concentration contributes to agglomeration in the media, increasing the size of the Au particles, and boosting the curcumin concentration leads to a higher density of functional groups, resulting in smaller Au NPs. FT-IR analysis reveals that the hydroxyl and phenolic groups of curcumin and F-108 are involved during the functionalization of Au surfaces. Enhancement in the fluorescence/RRS intensity is due to the combination of the influence of the shape/size of the Au NPs as well as the extent of curcumin conjugation at the interface of the Au NP surface and F-108. The presence of sugar molecules remarkably boosts the RRS intensity without significantly affecting the fluorescence and surface plasmon absorbance of the Au NPs; in contrast, the RRS intensity of standard CTAB functionalized Au NPs is unaffected by glucose molecules indicating that the functionalization of F-108 at Au surfaces is crucial. Interestingly, no interference from other potential interferents and antioxidant substances like ascorbic acid, creatinine and acetaminophen is observed. This method is simple and fast, and offers a wider linear dynamic range, 0-10 mM, that is applicable under physiological conditions and in serum samples. It is stable and provides an excellent recovery for serum samples, thus, potentially it can be useful in this field due to its low energy consumption, enzyme free assay, fast response time, better selectivity and sensitivity.

Hypoglycemic and hypolipidemic effects of a polysaccharide from flower buds of Lonicera japonica in streptozotocin-induced diabetic rats.

Hyperglycemia and dyslipidemia are classic features for diabetes mellitus (DM). In this study, one fraction of the crude polysaccharides extracted from Lonicera japonica flower buds (LJP) were investigated for its hypolipidaemic and hypoglycaemic activities by means of streptozotocin (STZ)-induced diabetic rats. Interestingly, after orally administrated with 800mg/kg body weight (B.W.) LJP for 42 days, the food and water intake and the levels of sugar and insulin in blood for the diabetic rats were drastically decreased, while the contents of liver and skeletal muscle glycogen and the concentrations of hepatic pyruvate kinase and hexokinase were obviously increased (p<0.01 or p<0.05). The levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterin (LDL-C) and very-low-density lipoprotein-cholesterin (VLDL-C) were significantly descended, while high-density lipoprotein-cholesterin (HDL-C) was significantly ascended (p<0.01 or p<0.05). In addition, the oxidant stress in liver was restored as well. The results suggested that LJP could be considered as an ingredient of functional foods for diabetes, and this is the first report about the hypoglycemic and hypolipidemic effects of the polysaccharides extracted from Lonicera japonica.