Identification of urinary metabolites with potential blood pressure-lowering effects in lentil-fed spontaneously hypertensive rats

Patterns of Alpha-Linolenic Acid Incorporation into Phospholipids in H4IIE Cells

Alpha linolenic acid (ALA) is an 18-carbon essential fatty acid found in plant-based foods and oils. While much attention has been placed on conversion of ALA to long chain polyunsaturated fatty acids, alternative routes of ALA metabolism exist and may lead to formation of other bioactive metabolites of ALA. The current study employed a non-targeted metabolomics approach to profile ALA metabolites that are significantly upregulated by ALA treatment. H4IIE hepatoma cells (n=3 samples per time point) were treated with 60 μM ALA or vehicle for 0, 0.25, 0.5, 1, 2, 3, 4, 6, 8, and 12 hours. Samples were then extracted with methanol and analyzed using high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. We observed selective changes in ALA incorporation into phospholipid classes and subclasses over the 12 hours following ALA treatment. While levels of specific molecular species of ALA-containing phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and lysophospholipids were elevated with ALA treatment, others were not affected. Of the phospholipids that were increased, some [e.g. PC(18:3/18:1), PC(18:3/18:4), PE(18:3/18:2), PE(18:3/18:3)] were elevated almost immediately after exposure to ALA, while others (e.g. PE(18:1/18:3) PA(18:3/22:6), and PA(18:3/18:2)] were not elevated until several hours after ALA treatment. Overall, these results suggest that ALA incorporation into phospholipids is selective and support a metabolic hierarchy for ALA incorporation into specific phospholipids. Given the functionality of phospholipids based on their fatty acid composition, future studies will need to investigate the implications of ALA incorporation into specific phospholipids on cell function.

Antihypertensive effect and underlying mechanism of tripeptide NCW on spontaneously hypertensive rats using metabolomics analysis

Tripeptide NCW identified in our previous study displayed a strong ACE inhibitory activity, but whether it has any antihypertensive effect in vivo remains unknown. Thus, in this study, we aimed to investigate the protective effects of tripeptide NCW in spontaneously hypertensive rats (SHRs) and to further figure out the serum metabolic profiling variations due to its oral administration via UPLC-Q-TOF-MS/MS-based metabolomics analysis to clarify the underlying hypotensive mechanism. After three weeks of oral administration, the tripeptide NCW-treated group (NCW/SHR group, 80 mg per kg BW per d) showed significantly reduced systolic and diastolic blood pressure by 48.08 ± 3.84 mmHg and 48.92 ± 5.77 mmHg, respectively. Additionally, a total of 25 blood pressure-related metabolites were identified as being significantly changed in SHRs given tripeptide NCW after three weeks. These 25 metabolites might be biomarkers that indicated that the tripeptide NCW exhibits antihypertensive activity via regulating bile acid metabolism, lipid metabolism, amino acid metabolism, purinergic signaling, pantothenate and CoA biosynthesis, and the citrate cycle. Collectively, tripeptide NCW has a protective effect on SHRs associated with serum metabolite abnormalities.

Blood pressure and urine metabolite changes in spontaneously hypertensive rats treated with leaf extract of Ficus deltoidea var angustifolia

Ficus deltoidea var angustifolia (FD-A) reduces blood pressure in spontaneously hypertensive rats (SHR) but the mechanism remains unknown. Changes in urine metabolites following FD-A treatment in SHR were, therefore, examined to identify the mechanism of its antihypertensive action. Male SHR were given either FD-A (1000 mg kg^-1 day^-1) or losartan (10 mg kg^-1 day^-1) or 0.5 mL of ethanolic-water (control) daily for 4 weeks. Systolic blood pressure (SBP) was measured every week and urine spectra data acquisition, on urine collected after four weeks of treatment, were compared using multivariate data analysis. SBP in FD-A and losartan treated rats was significantly lower than that in the controls after four weeks of treatment. Urine spectra analysis revealed 24 potential biomarkers with variable importance projections (VIP) above 0.5. These included creatine, hippurate, benzoate, trimethylamine N-oxide, taurine, dimethylamine, homocysteine, allantoin, methylamine, n-phenylacetylglycine, guanidinoacetate, creatinine, lactate, glucarate, kynurenine, ethanolamine, betaine, 3-hydroxybutyrate, glycine, lysine, glutamine, 2-hydroxyphenylacetate, 3-indoxylsulfate and sarcosine. From the profile of these metabolites, it seems that FD-A affects urinary levels of metabolites like taurine, hypotaurine, glycine, serine, threonine, alanine, aspartate and glutamine. Alterations in these and the pathways involved in their metabolism might underlie the molecular mechanism of its antihypertensive action.

Effect of Revtech thermal processing on volatile organic compounds and chemical characteristics of split yellow pea (Pisum sativum L.) flour

Yellow pea (Pisumsativum L.) is an economically rich source of nutrients with health-promoting effects. However, the consumption of pea ingredients is minimal due to their off-flavor characteristics. The present study investigated the effect of Revtech heat treatment on the chemical profile and volatile compounds in split yellow pea flour. Revtech treatment (RT) was applied at 140°C with a residence time of 4 min in dry condition (RT 0%) and in the presence of 10% steam (RT 10%). Both thermal treatments resulted in a significant reduction (p < 0.05) in lipoxygenase activity and the concentration of key beany-related odors such as heptanal, (E)-2-heptenal, 1-octen-3-ol, octanal, and (E)-2-octenal. In addition, RT 10% resulted in a significant reduction in pentanal, 1-penten-3-ol, hexanal, and 1-hexanol compared to untreated flour. The content of known precursors of lipoxygenase such as linoleic and linolenic acids was found in higher concentrations in heat-treated flours, indicating the efficacy of Revtech technology in minimizing the degradation of polyunsaturated fatty acids. No significant changes in the amino acid composition or the 29 selected phenolic compounds in pea flours were observed with Revtech processing except for two compounds, caffeic acid and gallocatechin, which were found at higher concentrations in RT 0%. PRACTICAL APPLICATION: Thermal processing of split yellow pea flours at 140°C using Revtech technology successfully decreased the concentrations of volatile compounds responsible for beany off-flavor while improving the nutritional quality of studied yellow pea flours. These results provide valuable information to the food industry for developing novel pulse-based products with enhanced sensory characteristics.

The Role of Pulses in Cardiovascular Disease Risk for Adults With Diabetes

Cardiovascular disease (CVD) is a leading cause of death among adults while associated comorbidities like diabetes further increase risks of CVD-related complications and mortality. Strategies to prevent and manage CVD risk, such as dietary change, are a key component for CVD and diabetes prevention and management. Pulses, defined as the dried edible seeds of plants in the legume family, have received attention for their superior nutritional composition as high-fiber, low-glycemic index foods and have been studied for their potential to reduce CVD and diabetes risk. Both observational and experimental studies conducted among adults with and without diabetes have provided support for pulses in their ability to improve lipid profiles, glycemic control, and blood pressure, all of which are major modifiable risk factors of CVD. These capabilities have been attributed to various mechanisms associated with the nutrient and phytochemical composition of pulses. Overall, this evidence provides support for the consumption of pulses as an important dietary strategy to reduce risk of CVD for those living with and without diabetes.

Discovery of Intake Biomarkers of Lentils, Chickpeas, and White Beans by Untargeted LC-MS Metabolomics in Serum and Urine

SCOPE

To identify reliable biomarkers of food intake (BFIs) of pulses.

METHODS AND RESULTS

A randomized crossover postprandial intervention study is conducted on 11 volunteers who consumed lentils, chickpeas, and white beans. Urine and serum samples are collected at distinct postprandial time points up to 48 h, and analyzed by LC-HR-MS untargeted metabolomics. Hypaphorine, trigonelline, several small peptides, and polyphenol-derived metabolites prove to be the most discriminating urinary metabolites. Two arginine-related compounds, dopamine sulfate and epicatechin metabolites, with their microbial derivatives, are identified only after intake of lentils, whereas protocatechuic acid is identified only after consumption of chickpeas. Urinary hydroxyjasmonic and hydroxydihydrojasmonic acids, as well as serum pipecolic acid and methylcysteine, are found after white bean consumption. Most of the metabolites identified in the postprandial study are replicated as discriminants in 24 h urine samples, demonstrating that in this case the use of a single, noninvasive sample is suitable for revealing the consumption of pulses.

CONCLUSIONS

The results of the present untargeted metabolomics work reveals a broad list of metabolites that are candidates for use as biomarkers of pulse intake. Further studies are needed to validate these BFIs and to find the best combinations of them to boost their specificity.

Seeds

A wide variety of plant species provide edible seeds. Seeds are the dominant source of human calories and protein. The most important and popular seed food sources are cereals, followed by legumes and nuts. Their nutritional content of fiber, protein, and monounsaturated/polyunsaturated fats make them extremely nutritious. They are important additions to our daily food consumption. When consumed as part of a healthy diet, seeds can help reduce blood sugar, cholesterol, and blood pressure.

Non-invasive exploration of metabolic profile of lung cancer with Magnetic Resonance Spectroscopy and Mass Spectrometry

BACKGROUND

Lung cancer is a major cause of global morbidity and mortality. Current low dose CT screening is invasive and its role remains contentious. There are no known biomarkers to monitor treatment response, detect disease recurrence and patient selection for adjuvant treatment after curative surgical resection. Hence there is an urgent need to explore non-conventional and non-invasive tools to develop novel biomarkers to improve the outcome of this lethal cancer.

METHODS

This is an ongoing exploratory and translational study involving collection of bio fluids from 50 patients with early stage non-small cell lung cancer before and after surgical resection. The primary objective is to identify cancer specific metabolome in body fluids - sputum, exhaled breath condensate, blood and urine of the patients with early stage non-small cell lung cancer using Magnetic Resonance Spectroscopy and Mass Spectroscopy.

CONCLUSION

The trajectory of change in metabolic profile of body fluids before and after surgical resection may have potential clinical applications in lung cancer screening, as biomarkers for disease recurrence and exploration of novel targets for therapeutic intervention.

Metabolomic characterization of myocardial ischemia-reperfusion injury in ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention

AIM

The aim of the study was to discover the metabolomic changes in plasma that occur during human Ischemia-Reperfusion (I/R) injury and to evaluate the diagnostic utility of plasma metabolomic biomarkers for determination of myocardial injury. Deciphering the details of plasma metabolome in ST-segment elevation myocardial infarction (STEMI) patients before and after primary percutaneous coronary interventions (PPCI) would allow for better understanding of the mechanisms involved during acute myocardial ischemia and reperfusion in humans. We performed a detailed non-targeted metabolomic analysis of plasma from 27 STEMI patients who had undergone PPCI in the first 48 hrs employing a LC-MS approach. Plasma metabolome at ischemic condition was compared to multiple time points after PPCI which allowed us to focus on changes in the reperfusion phase. Classification of the differential metabolites based on chemical taxonomy identified a major role for lipids and lipid-derived molecules. Biochemical pathway analysis identified valine, leucine and isoleucine biosynthesis, vitamin B6 metabolism and glutathione metabolism as the most significant metabolic pathways representing early response to I/R injury. We also identified phenyl alanine, tyrosine, linoleic acid and glycerophospholipid metabolism as the most significant pathways representing late response to I/R injury. A panel of three metabolites pentadecanoic acid, linoleoyl carnitine and 1-linoleoylglycerophosphocholine was discovered to have diagnostic value in determining the extent of I/R injury based on cardiac biomarkers. Using a non-targeted LC-MS approach, we have successfully generated the most comprehensive data to date on significant changes in the plasma metabolome in STEMI patients who had undergone PPCI in the first 48 hrs showing that lipid metabolites represent the largest cohort of molecules undergoing significant change.

Investigation of low molecular weight peptides (<1 kDa) in chicken meat and their contribution to meat flavor formation

BACKGROUND

Low molecular weight peptides (LMWPs) (<1 kDa) generated in meat during chilled conditioning can act as flavor precursors in the Maillard reaction with a potential contribution to key volatile organic compound (VOC) formation upon heating. Liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOF-MS) successfully detected 44 LMWPs in chicken breast and thigh muscles stored at 4 °C for up to 6 days. Carnosine (350 mg per 100 g), glutathione (GSH, 20 mg per 100 g) (concentrations based on reported values in the literature) and cysteine glycine (Cys Gly, 5 mg per 100 g) (concentration based on results from LC/QTOF-MS) were used in model systems containing ribose (25 mg per 100 g). The three model systems were heated at 180 °C for 2 h at pH 6.3. VOCs were measured by simultaneous distillation solvent extraction/gas chromatography/mass spectrometry.

RESULTS

Of 33 VOCs detected, 26 were significantly different (P ≤ 0.05) between the three peptides. The majority of nitrogen-containing volatiles, pyrazines and pyridines, dominated the carnosine mixture, while sulfur-containing VOCs dominated the GSH and Cys Gly peptide mixtures.

CONCLUSION

Known key aroma compounds such as thiazole (meaty), 2-methyl-3-furanthiol (beef and meat), 2-furfurylthiol (roasted), dihydro-2-methyl-3(2H)-thiophenone (meaty), 2-acetylthiazole (meaty and roasted) and pyrazine (meaty) were detected under conditions specific to aged and thermally treated chicken, suggesting a potential contribution to the overall sensory quality of cooked meat. © 2018 Society of Chemical Industry.

Insulin-like growth factor-1 activates AMPK to augment mitochondrial function and correct neuronal metabolism in sensory neurons in type 1 diabetes

OBJECTIVE

Diabetic sensorimotor polyneuropathy (DSPN) affects approximately half of diabetic patients leading to significant morbidity. There is impaired neurotrophic growth factor signaling, AMP-activated protein kinase (AMPK) activity and mitochondrial function in dorsal root ganglia (DRG) of animal models of type 1 and type 2 diabetes. We hypothesized that sub-optimal insulin-like growth factor 1 (IGF-1) signaling in diabetes drives loss of AMPK activity and mitochondrial function, both contributing to development of DSPN.

METHODS

Age-matched control Sprague-Dawley rats and streptozotocin (STZ)-induced type 1 diabetic rats with/without IGF-1 therapy were used for in vivo studies. For in vitro studies, DRG neurons from control and STZ-diabetic rats were cultured and treated with/without IGF-1 in the presence or absence of inhibitors or siRNAs.

RESULTS

Dysregulation of mRNAs for IGF-1, AMPKα2, ATP5a1 (subunit of ATPase), and PGC-1β occurred in DRG of diabetic vs. control rats. IGF-1 up-regulated mRNA levels of these genes in cultured DRGs from control or diabetic rats. IGF-1 treatment of DRG cultures significantly (P < 0.05) increased phosphorylation of Akt, P70S6K, AMPK and acetyl-CoA carboxylase (ACC). Mitochondrial gene expression and oxygen consumption rate (spare respiratory capacity), ATP production, mtDNA/nDNA ratio and neurite outgrowth were augmented (P < 0.05). AMPK inhibitor, Compound C, or AMPKα1-specific siRNA suppressed IGF-1 elevation of mitochondrial function, mtDNA and neurite outgrowth. Diabetic rats treated with IGF-1 exhibited reversal of thermal hypoalgesia and, in a separate study, reversed the deficit in corneal nerve profiles. In diabetic rats, IGF-1 elevated the levels of AMPK and P70S6K phosphorylation, raised Complex IV-MTCO1 and Complex V-ATP5a protein expression, and restored the enzyme activities of Complex IV and I in the DRG. IGF-1 prevented TCA metabolite build-up in nerve.

CONCLUSIONS

In DRG neuron cultures IGF-1 signals via AMPK to elevate mitochondrial function and drive axonal outgrowth. We propose that this signaling axis mediates IGF-1-dependent protection from distal dying-back of fibers in diabetic neuropathy.