Non-esterified fatty acids as biomarkers of diet and glucose homeostasis in pregnancy: The impact of fatty acid reporting methods: NEFA reporting methods affect dietary and cardiometabolic endpoints.

BACKGROUND: Sparse data exists on the utility of individual serum non-esterified fatty acids (NEFAs) as clinical and dietary biomarkers and how reporting methods could affect these associations. We investigated the associations of 19 serum NEFAs expressed as µM or mol%, with self-reported dietary intake data, and cardiometabolic health indicators in pregnant women. METHODS: In this cross-sectional study, 273 pregnant women in their second trimester each completed a semi-quantitative food-frequency questionnaire and provided fasting serum samples. Comprehensive serum NEFA analysis was performed by multisegment injection-nonaqueous capillary electrophoresis-mass spectrometry. We evaluated the associations of NEFAs using two different reporting methods, with diet quality, specific foods intake, and measures of adiposity and glucose homeostasis. RESULTS: Consistently stronger dietary correlations were observed when expressed as mol%. Serum ω-3 NEFAs were associated with diet quality and fish/fish oil daily servings (DHA mol%, r= 0.37; p = 4.8e-10), and odd-chain NEFAs were associated with full-fat dairy intake (15:0 mol%, r = 0.23; p = 9.0e-5). Glucose intolerance was positively associated with odd chain NEFAs as expressed in µM (r = 0.21; p= 0.001) but inversely associated when expressed as mol% (r = -0.31; p= 2.2e-7). In contrast, monounsaturated NEFAs (µM and mol%) had robust positive associations with pre-pregnancy BMI, second trimester skin-fold thickness, glycated hemoglobin, fasting glucose, and glucose intolerance. CONCLUSIONS: This study demonstrates the utility of specific NEFAs and their sub-classes as viable dietary and clinical biomarkers when reported as their relative proportions. More research is needed to investigate inconsistencies between absolute concentrations and relative proportions when reporting fatty acids.

Lipidomic profiling of plasma free fatty acids in type-1 diabetes highlights specific changes in lipid metabolism.

Type-1 diabetes mellitus (T1DM) is associated with metabolic changes leading to alterations in glucose and lipid handling. While T1DM-associated effects on many major plasma lipids have been characterised, such effects on plasma free fatty acids (FFA) have not been fully examined. Using gas chromatography-mass spectrometry, we measured the plasma concentrations of FFA species in individuals with T1DM (n = 44) and age/sex-matched healthy controls (n = 44). Relationships between FFA species and various parameters were evaluated. Plasma concentrations of myristate (14:0), palmitoleate (16:1), palmitate (16:0), linoleate (18:2), oleate (18:1c9), cis-vaccenate (18:1c11), eicosapentaenoate (20:5), arachidonate (20:4) and docosahexanoate (22:6) were reduced in the T1DM group (p < 0.0001 for all, except p = 0.0020 for eicosapentaenoate and p = 0.0068 for arachidonate); α-linolenate (18:3) and dihomo-γ-linolenate (20:3) concentrations were unchanged. The saturated/unsaturated FFA ratio, n-3/n-6 ratio, de novo lipogenesis index (palmitate (main lipogenesis product)/linoleate (only found in diet)) and elongase index (oleate/palmitoleate) were increased in the T1DM group (p = 0.0166, p = 0.0089, p < 0.0001 and p = 0.0008 respectively). The stearoyl-CoA desaturase 1 (SCD1) index 1 (palmitoleate/palmitate) and index 2 (oleate/stearate) were reduced in T1DM (p < 0.0001 for both). The delta-(5)-desaturase (D5D) index (arachidonate/dihomo-γ-linolenate) was unchanged. Age and sex had no effect on plasma FFA concentrations in T1DM, while SCD1 index 1 was positively correlated (p = 0.098) and elongase index negatively correlated with age (p = 0.0363). HbA1c was negatively correlated with all plasma FFA concentrations measured except α-linolenate and dihomo-γ-linolenate. Correlations were observed between plasma FFA concentrations and cholesterol and HDL concentrations, but not LDL concentration or diabetes duration. Collectively, these results aid our understanding of T1DM and its effects on lipid metabolism.

Volatile Profile in Yogurt Obtained from Saanen Goats Fed with Olive Leaves.

The aim of this study was to evaluate the development of volatile compounds in yogurt samples obtained from goats fed a dietary supplementation with olive leaves (OL). For this purpose, thirty Saanen goats were divided into two homogeneous groups of 15 goats each: a control group that received a standard diet (CG) and an experimental group whose diet was supplemented with olive leaves (OLG). The trial lasted 28 days, at the end of which the milk of each group was collected and used for yogurt production. Immediately after production, and after 7 days of storage at 4 °C in the absence of light, the yogurt samples were characterized in terms of fatty acid profile, oxidative stability and volatile compounds by the solid-phase microextraction (SPME)-GC/MS technique. Dietary OL supplementation positively affected the fatty acid composition, inducing a significant increase in the relative proportion of unsaturated fatty acids, mainly oleic acid (C18:1 cis9) and linolenic acid (C18:3). With regard to the volatile profile, both in fresh and yogurt samples stored for 7 days, the OL supplementation induced an increase in free fatty acids, probably due to an increase in lipolysis carried out by microbial and endogenous milk enzymes. Specifically, the largest variations were found for C6, C7, C8 and C10 free fatty acids. In the same samples, a significant decrease in aldehydes, mainly heptanal and nonanal, was also detected, supporting-at least in part-an improvement in the oxidative stability. Moreover, alcohols, esters and ketones appeared lower in OLG samples, while no significant variations were observed for lactones. These findings suggest the positive role of dietary OL supplementation in the production of goats' milk yogurt, with characteristics potentially indicative of an improvement in nutritional properties and flavor.

Plasma lipidomic signatures of spontaneous obese rhesus monkeys.

BACKGROUND: Obesity plays crucial roles in the pathogenesis of metabolic diseases such as hyperlipidemia, nonalcoholic fatty liver disease (NAFLD), and type 2 diabetes (T2D). The underlying mechanisms linking obesity to metabolic diseases are still less understandable. METHODS: Previously, we screened a group of spontaneously obese rhesus monkeys. Here, we performed a plasma lipidomic analysis of normal and obese monkeys using gas chromatography/mass spectroscopy (GC/MS) and ultra-high performance liquid chromatography/mass spectroscopy (UPLC/MS). RESULTS: In total, 143 lipid species were identified, quantified, and classified into free fatty acids (FFA), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylglycerol (PG), lysophosphatidylcholine (LPC), lysophosphatidic acid (LPA), and sphingomyelin (SM). Data analysis showed that the obese monkeys had increased levels of fatty acids palmitoleic acid (C16:1) and arachidonic acid (C20:4), FFA especially palmitic acid (C16:0), as well as certain PC species and SM species. Surprisingly, the plasma level of LPA-C16:0 was approximately four-fold greater in the obese monkeys. Conversely, the levels of most PE species were obviously reduced in the obese monkeys. CONCLUSION: Collectively, our work suggests that lipids such as FFA C16:0 and 16:0-LPA may be potential candidates for the diagnosis and study of obesity-related diseases.

A novel antidiabetic therapy: free fatty acid receptors as potential drug target.

Excessive dietary intake of fat is strongly involved in the development of type 2 diabetes (T2D). Free fatty acids (FFAs), which are provided from dietary fat, are not only important nutrients, but also act as signaling molecules and stimulate key biological functions. Recent physiological and pharmacological studies have shown that several G-protein coupled receptors, such as FFAR1-4, are receptors for FFAs. FFAR1 and FFAR4 are activated by medium- and long-chain fatty acids, whereas FFAR2 and FFAR3 are activated by short-chain fatty acids (SCFAs). These FFA receptors (FFARs) mediate various physiological functions, depending on the carbon chain length of the FFAs and the ligand specificity of the FFARs. Functional analyses have revealed that FFARs mediate important metabolic functions, such as peptide hormone secretion and inflammation, and thereby contribute to energy homeostasis. Since imbalances in energy homeostasis lead to metabolic disorders, such as obesity and T2D, FFARs are considered to be key therapeutic targets in these diseases. In particular, recent studies have shown that the administration of selective agonists of FFAR1 and FFAR4 improved glucose metabolism and ameliorated systemic metabolic disorders. Furthermore, the biological functions of SCFAs in anti-inflammation and energy metabolism are linked with the activation of FFAR2 and FFAR3. Hence, in this review, we summarize the physiological functions of FFARs and discuss the potential of selective ligands of FFARs for development as drugs to treat metabolic disorders, such as T2D and obesity.

Quantitative profile of lipid classes in blood by normal phase chromatography with evaporative light scattering detector: application in the detection of lipid class abnormalities in liver cirrhosis.

BACKGROUND: The lack of analytical methods specific for each lipid class, particularly for phospholipids and sphyngolipids, makes necessary their separation by preparative techniques before quantification. LC-MS would be the election method but for daily work in the clinical laboratory this is not feasible for different reasons, both economic and time consuming. In the present work, we have optimized an HPLC method to quantify lipid classes in plasma and erythrocytes and applied it to samples from patients with cirrhosis. METHODS: Lipid classes were analyzed by normal phase liquid chromatography with evaporative light scattering detection. We employed a quaternary solvent system to separate twelve lipid classes in 15 min. RESULTS: Interday, intraday and recovery for quantification of lipid classes in plasma were excellent with our methodology. The total plasma lipid content of cirrhotic patients vs control subjects was decreased with diminished CE (81±33 vs 160±17 mg/dL) and PC (37±16 vs 60±19 mg/dL). The composition of erythrocytes showed a decrease in acidic phospholipids: PE, PI and PS. CONCLUSION: Present methodology provides a reliable quantification of lipid classes in blood. The lipid profile of cirrhotics showed alterations in the PC/PE plasma ratio and in the phospholipid content of erythrocytes, which might reflect alterations in hepatocyte and erythrocyte membrane integrity.

Determination of free fatty acids in chocolate by liquid chromatography with tandem mass spectrometry.

This paper describes a rapid extraction method, based on a matrix solid-phase dispersion technique using diatomaceous earth as solid support and 50:50 (v/v) chloroform/methanol as extracting solvent, that can determine 11 free fatty acids in chocolate. The extraction procedure is followed by reversed-phase liquid chromatography/tandem mass spectrometry (LC/MS/MS) using a normal-bore (4.6 mm i.d.) C-18 column and an electrospray interface operating in the negative ion mode. The tandem mass spectra of selected compounds show that charge-remote fragmentation (CRF) mechanisms are occurring; the intensities of the CRF reactions increase with the carbon number and degree of unsaturation of the fatty acids. Average recoveries, evaluated by the standard addition method, vary between 79-103%, and the estimated quantification limits are less than 153 ng/g. The proposed method has been used to analyse nine chocolate samples from various price ranges, bought from supermarkets.

Measurement of free fatty acids in cerebrospinal fluid from patients with hemorrhagic and ischemic stroke.

Free fatty acid (FFA) concentrations in cerebrospinal fluid (CSF) from patients with ischemic and hemorrhagic stroke (n=25) and in contemporary controls (n=73) were examined using HPLC. Concentrations of CSF FFAs from ischemic and hemorrhagic stroke patients obtained within 48 h of the insult were significantly greater than in control patients. Higher concentrations of polyunsaturated fatty acids (PUFAs) in CSF obtained within 48 h of insult were associated with significantly lower (P<0.05) admission Glasgow Coma Scale scores and worse outcome at the time of hospital discharge, using the Glasgow Outcome Scale (P<0.01).

[Influence of free fatty acids on growth, sporulation and virulence of the parasitic fungus Conidiobolus coronatus]. / Wplyw wolnych kwasów tluszczowych na wzrost, sporulacje i wirulencje pasozytniczego grzyba Conidiobolus coronatus.

Five free fatty acids (FFA): C16:0, C18:0, C18:1, C18:2 and C18:3 were introduced into culture media in order to investigate differential development of pathogenic fungus Conidiobolus coronatus as a function of FFA concentration. All tested FFA showed fungistatic action inhibiting hyphae growth and sporulation. Fungal colonies grown in the presence of FFA showed decreased virulence.

High polyunsaturated fatty acid, thromboxane A2, and alpha-fetoprotein concentrations at the human feto-maternal interface.

Polyunsaturated fatty acids (PUFA) like arachidonic (C20:4) and docosahexaenoic (C22:6) acids are essential for harmonious fetal development. This study evaluates, at near term, the distributions of free fatty acids (FFA) and their fetal carrier protein, alpha-fetoprotein (AFP) in the maternal (M) and fetal circulation (umbilical arteries (A) and vein (V)), focusing on the feto-material interface where maternal intervillous blood (I) contacts the fetal trophoblast. FFA concentrations in intervillous and maternal blood were similar, while those in umbilical arteries and vein were 2- to 4-fold lower (P < 0.001). There were more saturated FFA in umbilical vein (41%) and arteries (44%) blood than in maternal (30%) and intervillous (32%) blood (P < 0.001). Monounsaturated FFA predominated (P < 0.001) in maternal (43%) blood, but not in intervillous (35%), umbilical vein (33%) and arteries (31%) blood. Di-triunsaturated FFA were similar in intervillous and maternal (25%) blood and lower in umbilical vein and arteries (16%) (P < 0.001). PUFA were low in maternal (2.5%) blood and higher in intervillous and umbilical vein and arteries (9%, P < 0.001); consequently, C20:4 (40 microM) and C22:6 (16 microM) were the most abundant in the intervillous space. The AFP concentrations and AFP lectin-reactive isoforms were similar in intervillous and umbilical vein and arteries blood, but immuno-electrophoresis revealed a particular AFP conformation (less immuno-reactive, more anionic) in the intervillous space, suggesting that AFP is heavily loaded with PUFA at the feto-maternal interface. Prostacyclin derived from C20:4 was similar in all compartments but the thromboxane A2 concentration was 10-fold higher in intervillous blood than in maternal and umbilical vein and arteries blood. Thus the feto-maternal interface has a specific pattern of cell signalling molecules that might critically influence parturition.

The use of an intravenous fish oil emulsion enriched with omega-3 fatty acids in patients with cystic fibrosis.

The effects of parenteral nutrition supplemented with a lipid emulsion enriched with the omega-3 fatty acids (FA), eicosapentaenoate (20:5n-3) and docosahexaenoate (22:6n-3), derived from fish oil were compared to a standard lipid emulsion containing omega-6 FA in patients with cystic fibrosis (CF). Patients were randomized to receive either Omegavenous 10%, which contains fish oil (IFO), or Liposyn III 10% (control) daily for 1 mo at a dose of 150 mg/kg. There were no observed allergic or toxic reactions, no abnormalities in liver function tests or coagulation parameters. To assess the bioavailability of the lipid administered, measurement of plasma free fatty acid (FFA) levels were made of the essential FA. There were no adverse changes in plasma levels of the omega-6 FA (18:2n-6, 18:3n-6, 20:3n-6, and 20:4n-6), and plasma levels of the omega-3 FA (20:5n-3 and 22:6n-3) increased significantly during the 1-mo study. There were no significant changes in plasma FFA profiles of the essential FA for the patients receiving the control lipid. The effect of treatment on pulmonary function was also investigated. There were no significant changes in FVC, FEV1, PEFR, FEV1/ FVC, or FEF25-75 (absolute value or percentage) over the 4 weeks of study in the group receiving IFO or control. This preliminary investigation suggests that intravenous administration of fish oils enriched with long chain omega-3 FA to patients with CF is safe and bioavailable.

Lipolysis of triglyceride-rich lipoproteins activates coagulant factor XII: a study in familial lipoprotein-lipase deficiency.

A high factor VII coagulant activity (VIIc), a marker of increased risk of coronary heart disease, is frequently found in types IIb and IV hyperlipidaemia, but its cause is not fully understood. Factor VII can be activated by factor XIIa, generated from factor XII upon activation of the contact system of coagulation. Ten patients with familial lipoprotein-lipase (LPL) deficiency and 10 healthy control subjects were therefore compared to explore the hypothesis that high concentrations of unesterified fatty acids (UFA), released from triglyceride-rich lipoproteins by LPL, are a source of factor XII activation and hence the increased VIIc that is observed post-prandially and in non-LPL-deficient hypertriglyceridaemic states. Mean plasma cholesterol and triglyceride concentrations were, respectively, 1.5- and 19-fold higher in the patients than controls, due to increases in very-low-density lipoproteins and chylomicrons. The concentration and composition of plasma UFA were similar in both groups. In conformity with the hypothesis, VIIc was not increased in the LPL-deficient group, despite their massive hypertriglyceridaemia. Furthermore, when the patients' plasma was treated with LPL, factor XII was activated promptly and substantially, whereas no similar effect was observed in the controls. These results suggest that high concentrations of circulating triglyceride-rich lipoproteins will increase VIIc in the presence of LPL.

Meibomian gland dysfunction. III. Meibomian gland lipids.

The lipid components of meibomian gland excreta were evaluated in rabbits after they received 2% topical epinephrine dropped into their eyes daily for a period of 6 months to a year to induce meibomian gland dysfunction (MGD). Changes were compared to excreta obtained from seven age-matched, untreated control rabbits. Comparison of the lipids from MGD lids with lipids obtained from control rabbits revealed, for clinically evident MGD, a marked increase in the lipids that are uniquely characteristic of epidermal tissue. These epidermal lipids are free sterols (large amounts) and a group of seven types of ceramides. The data are consistent with the hypothesis that the initiating factor of rabbit MGD is hyperkeratinization of the ductal epithelia. For clinically apparent MGD some hydrolysis of the sterol esters of the meibomian gland lipids also seems to have occurred. This was evidenced by the formation of an 8-fold increase in a cluster of anteiso fatty acids with chain lengths longer than C20 in the free fatty acid fraction. This group of free fatty acids was the same as the acids esterified to the sterol esters. We could detect no change in the lipid excreta obtained from rabbits that developed only subclinical MGD, consisting of orifice plugging and dilation of the duct.