The Positive Association between Plasma Myristic Acid and ApoCIII Concentrations in Cardiovascular Disease Patients Is Supported by the Effects of Myristic Acid in HepG2 Cells.

BACKGROUND: In the settings of primary and secondary prevention for coronary artery disease (CAD), a crucial role is played by some key molecules involved in triglyceride (TG) metabolism, such as ApoCIII. Fatty acid (FA) intake is well recognized as a main determinant of plasma lipids, including plasma TG concentration. OBJECTIVES: The aim was to investigate the possible relations between the intakes of different FAs, estimated by their plasma concentrations, and circulating amounts of ApoCIII. METHODS: Plasma samples were obtained from 1370 subjects with or without angiographically demonstrated CAD (mean ± SD age: 60.6 ± 11.0 y; males: 75.8%; BMI: 25.9 ± 4.6 kg/m2; CAD: 73.3%). Plasma lipid, ApoCIII, and FA concentrations were measured. Data were analyzed by regression models adjusted for FAs and other potential confounders, such as sex, age, BMI, diabetes, smoking, and lipid-lowering therapies. The in vitro effects of FAs were tested by incubating HepG2 hepatoma cells with increasing concentrations of selected FAs, and the mRNA and protein contents in the cells were quantified by real-time RT-PCR and LC-MS/MS analyses. RESULTS: Among all the analyzed FAs, myristic acid (14:0) showed the most robust correlations with both TGs (R = 0.441, P = 2.6 × 10-66) and ApoCIII (R = 0.327, P = 1.1 × 10-31). By multiple regression analysis, myristic acid was the best predictor of both plasma TG and ApoCIII variability. Plasma TG and ApoCIII concentrations increased progressively at increasing concentrations of myristic acid, independently of CAD diagnosis and gender. Consistent with these data, in the in vitro experiments, an ∼2-fold increase in the expression levels of the ApoCIII mRNA and protein was observed after incubation with 250 µM myristic acid. A weaker effect (∼30% increase) was observed for palmitic acid, whereas incubation with oleic acid did not affect ApoCIII protein or gene expression. CONCLUSIONS: Plasma myristic acid is associated with increased ApoCIII concentrations in cardiovascular patients. In vitro experiments indicated that myristic acid stimulates ApoCIII expression in HepG2 cells.

Circulating Saturated Fatty Acids and Incident Type 2 Diabetes: A Systematic Review and Meta-Analysis.

The effect of saturated fatty acids (SFAs) on incident type 2 diabetes (T2D) is controversial and few have systematically appraised the evidence. We conducted a comprehensive search of prospective studies examining these relationships that were published in PubMed, Web of Science, or EMBASE from 21 February 1989 to 21 February 2019. A total of 19 studies were included for systematic review and 10 for meta-analysis. We estimated the summarized relative risk (RR) and 95% confidence interval (95% CI) using a random (if I2 > 50%) or a fixed effects model (if I2 ≤ 50%). Although the included studies reported inconclusive results, the majority supported a protective effect of odd-chain and an adverse impact of even-chain SFAs. Meta-analysis showed that the per standard deviation (SD) increase in odd-chain SFAs was associated with a reduced risk of incident T2D (C15:0: 0.86, 0.76-0.98; C17:0: 0.76, 0.59-0.97), while a per SD increase in one even-chain SFA was associated with an increased risk of incident T2D (C14:0: 1.13, 1.09-1.18). No associations were found between other SFAs and incident T2D. In conclusion, our findings suggest an overall protective effect of odd-chain SFAs and the inconclusive impact of even- and very-long-chain SFAs on incident T2D.

Profiling of carboxyl-containing metabolites in smokers and non-smokers by stable isotope labeling combined with LC-MS/MS.

Profiling of carboxyl-containing metabolites in smokers and non-smokers provides insight into the smoking-related biological events and causal relationships between exposure and adverse events. However, more comprehensive analysis of carboxyl-containing metabolites in bio-matrices with high sensitivity and accuracy is challenging. In this work, stable isotope labeling in combination with liquid chromatography-tandem mass spectrometry was used for untargeted profiling and relative quantification of carboxyl-containing metabolites in plasma of smokers and non-smokers. A pair of isotope labeling reagents, N, N-dimethylethylenediamine (DMED) and d4-DMED was used to label carboxyl-containing metabolites. Since the isotope labeled dimethylamino moieties of DMED and d4-DMED are easily fragmented and lost as characteristic neutral fragments of 45 and 49 Da, respectively, double neutral loss scans can be used to profiling of carboxyl-containing metabolites. Subsequently, based on the ion pair parameters obtained from double neutral loss scans, relative quantification method was developed. As a result, 269 carboxyl-containing metabolite candidates were discovered, and 88 metabolite candidates were found to have significant alterations between smokers and non-smokers. 7Z, 10Z-hexadecadienoic acid, myristic acid and 3ß-hydroxy-5-cholestenoic acid with significant differences confirmed by standard comparison are linked to smoking related inflammation, abnormal bile acid synthesis and cholesterol metabolism.

Priority use of medium-chain fatty acids during high-intensity exercise in cross-country skiers.

BACKGROUND: One of the topics discussed in sports science is the use of medium-chain saturated fat as an energy-saving nutrient additive when approaching high-intensity exercise. The purpose of this study was to compare the blood concentrations of medium-chain and long-chain fatty acids (FAs) across different intensity loads. METHODS: Fifteen male highly trained athletes from the Russian cross-country skiing team participated in the study. Blood samples were drawn at rest, at the peak of veloergometric test with a growing exercise load till exhaustion (97-100% VO2max), and after competitions. The plasma FA profile was determined using gas-liquid chromatography. RESULTS: We observed a substantial increase in the concentrations of capric acid (С10:0) (+ 164.1%), lauric acid (С12:0) (+ 223.9%), and myristic acid (С14:0) (+ 130.2%) in skiers after a sprint distance (1.3 km). A less intense increase in the concentrations of these acids (p < 0.05) was observed after a middle length distance or cycle exercise «until exhaustion¼. No significant differences in long-chain saturated FA content relative to baselines during exercise tests or competitions were revealed. CONCLUSIONS: In conclusion, the obtained results demonstrate activation of the lipolysis and the oxidation of medium-chain FA involved in the energy supply for highly trained athletes at maximum exercise loads.

Erythrocyte Saturated Fatty Acids and Incident Type 2 Diabetes in Chinese Men and Women: A Prospective Cohort Study.

The association between circulating saturated fatty acids (SFAs) and incident type 2 diabetes (T2D) is reported in Western populations with inconsistent results, while evidence from Asian populations is scarce. We aimed to examine the associations between erythrocyte SFAs and incident T2D in a Chinese population. Between 2008 and 2013, a total of 2683 participants, aged 40⁻75 years, free of diabetes were included in the present analyses. Incident T2D cases were ascertained during follow-up visits. Gas chromatography was used to measure erythrocyte fatty acids at baseline. The Cox proportional hazards model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs). During 13,508 person years of follow-up, 216 T2D cases were identified. Compared with the first quartile, multivariable-adjusted HRs (95% CIs) of the fourth quartile were 1.20 (0.82⁻1.76; p = 0.242) for myristic acid (14-carbon tail, zero double bonds; 14:0), 0.69 (0.48⁻0.99; p = 0.080) for palmitic acid (16:0), 1.49 (1.02⁻2.19; p = 0.047) for stearic acid (18:0), 1.46 (1.00⁻2.12; p = 0.035) for arachidic acid (20:0), 1.48 (0.99⁻2.22; p = 0.061) for behenic acid (22:0), and 1.08 (0.74⁻1.56; p = 0.913) for lignoceric acid (24:0). Our findings indicate that individual erythrocyte SFAs are associated with T2D in different directions, with 18:0 and 20:0 SFAs positively associated with the risk, whereas no convincing inverse association for 16:0 SFAs.

Monitoring tyrosine kinase inhibitor therapeutic responses with a panel of metabolic biomarkers in chronic myeloid leukemia patients.

The aim of this study is to investigate the potential biomarkers associated with chronic myeloid leukemia (CML), reveal the metabolite changes related to the continuous phases of tyrosine kinase inhibitors (TKIs), and find the potential biomarkers associated with treatment effects. Fifty-two patients with CML and 26 matched healthy people were enrolled as the discovery set. Another 194 randomly selected CML patients treated with TKI were chosen as the external validation set. Plasma samples from the patients and controls were profiled using the gas chromatography-mass spectrometry-based metabonomic approach. Multivariate and univariate statistical analyses were combined to select the differential metabolic features. The gas chromatography-mass spectrometry-based metabolomics showed a clear clustering and separation of metabolic patterns from healthy controls and pre- and post-TKI treatment CML patients in the discovery set. We identified 9 metabolites that differentiated CML patients from healthy controls, including lactic acid, isoleucine, glycerol, glycine, myristic acid, d-sorbitol, d-galactose, d-glucose, and myo-inositol. Among the 9 markers, glycerol and myristic acid had the most significant association with TKI treatment effects in both discovery and external validation sets. In the receiver operating characteristic analysis, the combination of glycerol and myristic acid showed a better discrimination performance compared to a single biomarker. The results indicated that metabolic profiling has the potential for diagnosis of CML and the panel of biomarkers including myristic acid and glycerol could be useful in monitoring TKI therapeutic responses.

Metabolomic Signature of Endometrial Cancer.

Endometrial cancer (EC) is the most common cancer of the female reproductive tract in developed countries. At the moment, no effective screening system is available. Here, we evaluate the diagnostic performance of a serum metabolomic signature. Two enrollments were carried out, one consisting of 168 subjects: 88 with EC and 80 healthy women, was used for building the classification models. The second (used to establish the performance of the classification algorithm) was consisted of 120 subjects: 30 with EC, 30 with ovarian cancer, 10 with benign endometrial disease, and 50 healthy controls. Two ensemble models were built, one with all EC versus controls (Model I) and one in which EC patients were aggregated according to their histotype (Model II). Serum metabolomic analysis was conducted via gas chromatography-mass spectrometry, while classification was done by an ensemble learning machine. Accuracy ranged from 62% to 99% for the Model I and from 67% to 100% for the Model II. Ensemble model showed an accuracy of 100% both for Model I and II. The most important metabolites in class separation were lactic acid, progesterone, homocysteine, 3-hydroxybutyrate, linoleic acid, stearic acid, myristic acid, threonine, and valine. The serum metabolomics signature of endometrial cancer patients is peculiar because it differs from that of healthy controls and from that of benign endometrial disease and from other gynecological cancers (such as ovarian cancer).

Association between increased visceral fat area and alterations in plasma fatty acid profile in overweight subjects: a cross-sectional study.

BACKGROUND: Visceral fat accumulation in overweight status has been resulted in changes of fatty acid profiles. The fatty acids profiles can be altered by fatty acid desaturase; the activity of which is highly associated with obesity and other metabolic diseases. We hypothesized that fatty acid composition, desaturase activity, and accumulation of visceral fat are interrelated. Thus, the aim of this study was to investigate the association between increased visceral fat area and alterations in plasma fatty acid profile in overweight subjects with different amounts of visceral fat. METHODS: Healthy overweight subjects (25.0 kg/m2 ≤ BMI < 30 kg/m2, n=232) were classified into lower (T1), middle (T2), and upper tertiles (T3) according to L4 visceral fat area (T1: <71.8 cm2, T2: 71.8 cm2-99.6 cm2, T3: >99.6 cm2). RESULTS: The T3 group showed higher amounts of cis-10-heptadecenoic acid and activity of C16 Δ9-desaturase and C18 Δ9-desaturase and lower activity of Δ5-desaturase than the T1 group. Additionally, the T3 group showed higher amounts of saturated fatty acids, myristic acid, palmitic acid, stearic acid, monounsaturated fatty acids, palmitoleic acid, oleic acid, n-6 polyunsaturated fatty acids, linoleic acid, dihomo-γ-linolenic acid, arachidonic acid, n-3 PUFAs, and docosapentaenoic acid than the T1 and T2 groups. CONCLUSIONS: This study indicates that greater than a certain area (>99.6 cm2) of visceral fat is needed to observe altered levels of individual fatty acid species and desaturase activities. The results suggest that increased activity of C16 Δ9-desaturase and C18 Δ9-desaturase in parallel with decreased Δ5-desaturase activity may be a causative factor in disturbed fatty acid metabolism.

The Effect of Chinese Herbal Medicine Formula mKG on Allergic Asthma by Regulating Lung and Plasma Metabolic Alternations.

Asthma is a chronic inflammatory disorder of the airway and is characterized by airway remodeling, hyperresponsiveness, and shortness of breath. Modified Kushen Gancao Formula (mKG), derived from traditional Chinese herbal medicines (TCM), has been demonstrated to have good therapeutic effects on experimental allergic asthma. However, its anti-asthma mechanism remains currently unknown. In the present work, metabolomics studies of biochemical changes in the lung tissue and plasma of ovalbumin (OVA)-induced allergic asthma mice with mKG treatment were performed using ultra high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Partial least squares-discriminate analysis (PLS-DA) indicated that the metabolic perturbation induced by OVA was reduced after mKG treatment. A total of twenty-four metabolites involved in seven metabolic pathways were identified as potential biomarkers in the development of allergic asthma. Among them, myristic acid (L3 or P2), sphinganine (L6 or P4), and lysoPC(15:0) (L12 or P16) were detected both in lung tissue and plasma. Additionally, l-acetylcarnitine (L1), thromboxane B2 (L2), 10-HDoHE (L10), and 5-HETE (L11) were first reported to be potential biomarkers associated with allergic asthma. The treatment of mKG mediated all of those potential biomarkers except lysoPC(15:0) (P16). The anti-asthma mechanism of mKG can be achieved through the comprehensive regulation of multiple perturbed biomarkers and metabolic pathways.

Unbound free fatty acid profiles in human plasma and the unexpected absence of unbound palmitoleate.

We determined for the first time the profiles of the nine most abundant unbound FFAs (FFAus) in human plasma. Profiles were determined for a standard reference plasma of pooled healthy adults for which the Lipid MAPSMAPS Consortium had determined the total FFA profiles. Measurements were performed by using 20 different acrylodan-labeled fatty acid binding protein mutants (probes), which have complementary specificities for the nine FFAs that comprise more than 96% of long-chain plasma FFA. The acrylodan fluorescence emission for each probe changes upon binding a FFAu. The plasma concentrations of each of the nine FFAus were determined by combining the measured fluorescence ratios of the 20 probes. The total molar FFAu concentration accounted for <10-5 of the total FFA concentration, and the mole fractions of the FFAu profiles were substantially different than the total FFA profiles. Myristic acid, for example, comprises 22% of the unbound versus 2.8% of the total. The most surprising difference is our finding of zero unbound cis-9-palmitoleic acid (POA), whereas the total POA was 7.2%. An unidentified plasma component appears to specifically prevent the release of POA. FFAus are the physiologically active FFAs, and plasma FFAu profiles may provide novel information about human health.

Myristic acid is associated to low plasma HDL cholesterol levels in a Mediterranean population and increases HDL catabolism by enhancing HDL particles trapping to cell surface proteoglycans in a liver hepatoma cell model.

BACKGROUND: HDL-C plasma levels are modulated by dietary fatty acid (FA), but studies investigating dietary supplementation in FA gave contrasting results. Saturated FA increased HDL-C levels only in some studies. Mono-unsaturated FA exerted a slight effect while poly-unsaturated FA mostly increased plasma HDL-C. AIMS: This study presents two aims: i) to investigate the relationship between HDL-C levels and plasma FA composition in a Sicilian population following a "Mediterranean diet", ii) to investigate if FA that resulted correlated with plasma HDL-C levels in the population study and/or very abundant in the plasma were able to affect HDL catabolism in an "in vitro" model of cultured hepatoma cells (HepG2). RESULTS: plasma HDL-C levels in the population correlated negatively with myristic acid (C14:0, ß = -0.24, p < 0.01), oleic acid (C18:1n9, ß = -0.22, p < 0.01) and cis-11-Eicosenoic (C20:1n9, ß = -0.19, p = 0.01) and positively with palmitoleic acid (C16:1, ß = +0.19, p = 0.03). HepG2 cells were conditioned with FA before evaluating HDL binding kinetics, and only C14:0 increased HDL binding by a non-saturable pathway. After removal of heparan sulphate proteoglycans (HSPG) by heparinases HDL binding dropped by 29% only in C14:0 conditioned cells (p < 0.05). C14:0 showed also the highest internalization of HDL-derived cholesteryl esters (CE, +32% p = 0.01 vs. non-conditioned cells). CONCLUSIONS: C14:0 was correlated with decreased plasma HDL-C levels in a Mediterranean population. C14:0 might reduce HDL-C levels by increasing HDL trapping to cell surface HSPG and CE stripping from bound HDL. Other mechanisms are to be investigated to explain the effects of other FA on HDL metabolism.

Metabolites in Blood for Prediction of Bacteremic Sepsis in the Emergency Room.

A metabolomics approach for prediction of bacteremic sepsis in patients in the emergency room (ER) was investigated. In a prospective study, whole blood samples from 65 patients with bacteremic sepsis and 49 ER controls were compared. The blood samples were analyzed using gas chromatography coupled to time-of-flight mass spectrometry. Multivariate and logistic regression modeling using metabolites identified by chromatography or using conventional laboratory parameters and clinical scores of infection were employed. A predictive model of bacteremic sepsis with 107 metabolites was developed and validated. The number of metabolites was reduced stepwise until identifying a set of 6 predictive metabolites. A 6-metabolite predictive logistic regression model showed a sensitivity of 0.91(95% CI 0.69-0.99) and a specificity 0.84 (95% CI 0.58-0.94) with an AUC of 0.93 (95% CI 0.89-1.01). Myristic acid was the single most predictive metabolite, with a sensitivity of 1.00 (95% CI 0.85-1.00) and specificity of 0.95 (95% CI 0.74-0.99), and performed better than various combinations of conventional laboratory and clinical parameters. We found that a metabolomics approach for analysis of acute blood samples was useful for identification of patients with bacteremic sepsis. Metabolomics should be further evaluated as a new tool for infection diagnostics.

Associations of dairy intake with glycemia and insulinemia, independent of obesity, in Brazilian adults: the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

BACKGROUND: Inverse associations between dairy intake and the risk of type 2 diabetes have been shown, but more studies are needed, especially from low- and middle-income countries. OBJECTIVE: The objective was to describe the association between dairy products and direct measures of glycemic status in adults without known diabetes. DESIGN: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) includes 15,105 adults, aged 35-74 y, enrolled from universities and research institutions in 6 Brazilian capital cities. We excluded participants with a known diabetes diagnosis, cardiovascular diseases, and cancer. Dairy consumption was assessed by a food-frequency questionnaire, and we computed servings per day for total and subgroups of dairy. Associations with fasting blood glucose (FG) and fasting insulin, 2-h postload glucose (PG), 2-h postload insulin (PI), glycated hemoglobin (Hb A1c), and homeostasis model assessment of insulin resistance (HOMA-IR) were assessed through multivariable linear regression analysis with adjustment for demographic characteristics, behavioral risk factors, other dietary factors, and anthropometric measurements. RESULTS: The sample size after exclusions was 10,010. The intake of total dairy was inversely associated with FG (linear ß for dairy servings/d = -0.46 ± 0.2 mg/dL), PG (-1.25 ± 0.5 mg/dL), PI (-1.52 ± 0.6 mg/dL), Hb A1c (-0.02 ± 0.0%), and HOMA-IR (-0.04 ± 0.0) after adjustment for all covariates (P < 0.05 for all). The findings were consistent across categories of sex, race, obesity status, and dairy fat amount (reduced-fat vs. full-fat dairy). Fermented dairy products showed particularly strong inverse associations with the outcomes, with adjusted differences for a 1-serving/d increment of -0.24 (95% CI: -0.46, -0.02) mg/dL for FG, -0.86 (-1.42, -0.30) mg/dL for PG, and -0.01% (-0.02%, 0.00%) for Hb A1c. Myristic acid was the only nutrient that appeared to mediate the association between dairy intake and glycemia. CONCLUSION: Dairy intake, especially fermented dairy, was inversely associated with measures of glycemia and insulinemia in Brazilian adults without diagnosed diabetes. This trial was registered at clinicaltrials.com as NCT02320461.

Dietary Effects on Plasma Glycerophospholipids.

OBJECTIVE: Human milk provides a complex mixture of animal lipids, whereas the fat supply of most modern infant formula is based on vegetable oils. We studied the effects of breast-feeding and of feeding infant formula either without or with dairy goat lipids on the composition of infant plasma glycerophospholipids. METHODS: Healthy-term infants were randomized double blind to feeding with infant formula based on whole goats' milk (GIF, approximately 60% milk fat and 40% vegetable oils) or a control cows' milk infant formula based on vegetable oils (VIF) from 2 weeks after birth. A reference group of fully breast-fed infants was also followed. At the age 4 months, blood samples were collected and plasma glycerophospholipids were analyzed with liquid chromatography coupled to triple quadrupole mass spectrometry. RESULTS: The group of breast-fed infants showed significantly higher contents of glycerophospholipid species containing sn-2 palmitic acid [PC(16:0/16:0) and PC(18:0/16:0)] and significantly higher contents of glycerophospholipid species containing long-chain polyunsaturated fatty acids than infants in both formula groups. The GIF group demonstrated significantly higher glycerophospholipid species containing myristic acid [LPC(14:0), PC(14:0/18:1), PC(16:0/14:0)] and palmitoleic acid [LPC(16:1), PC(16:0/16:1), and PC(16:1/18:1)] than the VIF group. CONCLUSIONS: We conclude that breast-feeding induces marked differences in infant plasma glycerophospholipid profiles compared with formula feeding, whereas the studied different sources of formula fat resulted in limited effects on plasma glycerophospholipids.

Plasma free fatty acid levels influence Zn(2+) -dependent histidine-rich glycoprotein-heparin interactions via an allosteric switch on serum albumin.

BACKGROUND: Histidine-rich glycoprotein (HRG) regulates coagulation through its ability to bind and neutralize heparins. HRG associates with Zn(2+) to stimulate HRG-heparin complex formation. Under normal conditions, the majority of plasma Zn(2+) associates with human serum albumin (HSA). However, free fatty acids (FFAs) allosterically disrupt Zn(2+) binding to HSA. Thus, high levels of circulating FFAs, as are associated with diabetes, obesity, and cancer, may increase the proportion of plasma Zn(2+) associated with HRG, contributing to an increased risk of thrombotic disease. OBJECTIVES: To characterize Zn(2+) binding by HRG, examine the influence that FFAs have on Zn(2+) binding by HSA, and establish whether FFA-mediated displacement of Zn(2+) from HSA may influence HRG-heparin complex formation. METHODS: Zn(2+) binding to HRG and to HSA in the presence of different FFA (myristate) concentrations were examined by isothermal titration calorimetry (ITC) and the formation of HRG-heparin complexes in the presence of different Zn(2+) concentrations by both ITC and ELISA. RESULTS AND CONCLUSIONS: We found that HRG possesses 10 Zn(2+) sites (K' = 1.63 × 10(5) ) and that cumulative binding of FFA to HSA perturbed its ability to bind Zn(2+) . Also Zn(2+) binding was shown to increase the affinity with which HRG interacts with unfractionated heparins, but had no effect on its interaction with low molecular weight heparin (~ 6850 Da). [Correction added on 1 December 2014, after first online publication: In the preceding sentence, "6850 kDa" was corrected to "6850 Da".] Speciation modeling of plasma Zn(2+) based on the data obtained suggests that FFA-mediated displacement of Zn(2+) from serum albumin would be likely to contribute to the development of thrombotic complications in individuals with high plasma FFA levels.

NMR metabolomics profiling of blood plasma mimics shows that medium- and long-chain fatty acids differently release metabolites from human serum albumin.

Metabolite profiling by NMR of body fluids is increasingly used to successfully differentiate patients from healthy individuals. Metabolites and their concentrations are direct reporters of body biochemistry. However, in blood plasma the NMR-detected free-metabolite concentrations are also strongly affected by interactions with the abundant plasma proteins, which have as of yet not been considered much in metabolic profiling. We previously reported that many of the common NMR-detected metabolites in blood plasma bind to human serum albumin (HSA) and many are released by fatty acids present in fatted HSA. HSA is the most abundant plasma protein and main transporter of endogenous and exogenous metabolites. Here, we show by NMR how the two most common fatty acids (FAs) in blood plasma - the long-chain FA, stearate (C18:0) and medium-chain FA, myristate (C14:0) - affect metabolite-HSA interaction. Of the set of 18 common NMR-detected metabolites, many are released by stearate and/or myristate, lactate appearing the most strongly affected. Myristate, but not stearate, reduces HSA-binding of phenylalanine and pyruvate. Citrate signals were NMR invisible in the presence of HSA. Only at high myristate-HSA mole ratios 11:1, is citrate sufficiently released to be detected. Finally, we find that limited dilution of blood-plasma mimics releases HSA-bound metabolites, a finding confirmed in real blood plasma samples. Based on these findings, we provide recommendations for NMR experiments for quantitative metabolite profiling.

[Investigation of fatty acid profile for diagnostic purposes in mouse melanoma]. / A szérum zsírsavprofil diagnosztikus jelentõségének vizsgálata kísérletes modellben.

The aim of this study was to investigate whether fatty acid profile is a suitable marker for diagnostic purposes in mouse melanoma. Twelve C57Bl/6 male mice were implanted with B16 mouse melanoma cells (106 cells/animal) orthotopically (subcutaneously). After the implantation 4-4 animals were bled by cardiac puncture following narcosis, at days 7, 14, and 21. In order to investigate fatty acid profiles a method based on extraction and HPLC-MS was developed. Signal intensities of 14 fatty acids were determined by mass spectrometry in tumor-free animals as well as tumor bearing animals at the three time points. Mathematical analysis showed non-significant profile changes when control (tumor-free) animals were compared to tumor-implanted ones as well as during tumor progression on week 1, 2 and 3. In case of three fatty acids (myristic acid, palmitoleic acid and eicosadienoic acid) a trend was observed during tumor progression but its statistical significance cannot be evaluated without further investigations. The fatty acid profile cannot be used for early diagnoses in mouse melanoma.

Differential effect of cheese fatty acid composition on blood lipid profile and redox status in normolipidemic volunteers: a pilot study.

The present study investigated the effect of the consumption of two cheese varieties differing for fat quality on blood lipid profile and redox status biomarkers in 30 selected healthy volunteers, consuming either the experimental cheese (from milk produced by cows fed a grass and maize silage based diet with 5% of linseed oil added) or the control cheese (from normal cows' milk) for 4 weeks according to a crossover design. The experimental cheese had a lower content of medium-chain saturated fatty acids and a higher content of stearic acid and polyunsaturated fatty acids; its consumption led to higher levels of vitamins C and E and stearic acid in blood, while myristic acid and oxidized low-density lipoprotein concentrations were significantly lower. As myristic acid and oxidized low-density lipoprotein are highly correlated with increased atherogenic risk and vitamins C and E with antioxidant activity, the enrichment of cows' diet with linseed oil could provide a dietary option to prevent cardiovascular diseases risk.