Individual Free Fatty Acids Research Articles

Trauma metabolism and the heart: Uptake of substrates and effects of insulin early after cardiac operations

In a controlled, randomized study the myocardial uptake/release of individual free fatty acids, glucose, lactate, pyruvate, alanine, and glycerol was studied 1 hour after completion of coronary operations. The effects of insulin were evaluated by means of a hyperinsulinemic "clamp" technique. No significant uptake of free fatty acids was found despite markedly elevated arterial concentrations (mean +/- standard error of the mean, 2.01 +/- 0.19 mmol.L-1), oleic acid, together with palmitic and linoleic acid, constituting 80% of the total plasma free fatty acid level. Insulin treatment (1 unit.kg bw-1.hr-1) prevented a further increase of the plasma free fatty acid level, observed concomitantly in the control group. Insulin affected all individual free fatty acids similarly. Changes in plasma free fatty acid levels occurring during the study and the corresponding myocardial uptake correlated (rS = 0.50 to 0.81). No significant uptake or release of glucose, lactate pyruvate, and glycerol occurred, whereas a myocardial release of alanine was seen. The heart and the concomitant leg uptake/release of glucose (rS = 0.40, p less than 0.05) and lactate (rS = 0.67, p less than 0.01) correlated. A substantial uptake of glucose was achieved and a more positive myocardial balance was obtained for alanine, lactate, and pyruvate with insulin. The changes in heart and the concomitant leg uptake/release correlated (glucose, rS = 0.62, p less than 0.01; lactate, rS = 0.64, p less than 0.01; pyruvate, rS = 0.71, p less than 0.01). It is concluded that the myocardial uptake of substrates during the first hours after coronary surgery is markedly abnormal with no uptake of free fatty acids or carbohydrates. These changes can be explained to some extent by the insulin resistance of trauma metabolism and can be modified by insulin treatment.

Effect of mild hypothermia on ischemia-induced release of neurotransmitters and free fatty acids in rat brain.

We have demonstrated previously that mild intraischemic hypothermia confers a marked protective effect on the final histopathological outcome. The present study was carried out to evaluate whether this protective effect involves changes in the degree of local cerebral blood flow reductions, tissue accumulation of free fatty acids, or alterations in the extracellular release of glutamate and dopamine. Rats whose intraischemic brain temperature was maintained at 36 degrees C, 33 degrees C, or 30 degrees C were subjected to 20 minutes of ischemia by four-vessel occlusion combined with systemic hypotension. Levels of local cerebral blood flow, as measured autoradiographically, were reduced uniformly in all experimental animals at the end of ischemia by gas chromatography after tissue extraction and separation by thin layer chromatography. A massive ischemia-induced accumulation of individual free fatty acids was observed in animal groups whose intraischemic brain temperature was maintained at either 36 degrees C or 30 degrees C. Extracellular neurotransmitter levels were measured by microdialysis; the perfusate was collected before, during, and after ischemia. In rats whose intraischemic brain temperature was maintained at 36 degrees C, dopamine and glutamate increased significantly during ischemia and the early period of recirculation (by 500-fold and sevenfold, respectively). In animals whose brain temperature was maintained at 33 degrees C and 30 degrees C, the release of glutamate was completely inhibited, and the release of dopamine was significantly attenuated (by 60%). These results suggest that mild intraischemic hypothermia does not affect the ischemia-induced local cerebral blood flow reduction or free fatty acid accumulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Individual free fatty acids and lactate uptake in the human heart during severe sepsis.

Coronary haemodynamics and myocardial metabolism of nonesterified fatty acids (NEFA) and lactate were studied in 11 patients with severe sepsis, and compared to 10 control subjects. Coronary sinus blood flow was evaluated by thermodilution. Arterial and coronary sinus blood samples were collected for the measurement of lactate and total and individual NEFA concentrations both in septic and control patients. There was an increase in lactate and total NEFA arterial concentrations with a marked increase in palmitic and linolenic acids. The uptake of the main NEFA (C14:0 to C18:2) was significantly decreased. In the control group, individual NEFA uptake was proportional to their arterial concentrations. This relationship was not observed in patients with sepsis: there was no preferential extraction of any particular NEFA. Furthermore, in patients with sepsis, myocardial oxygen consumption did not correlate with NEFA, but only with lactate uptake. Alterations in NEFA uptake were found to be constant during severe sepsis and are consistent with major disturbances in myocardial metabolism.

Lipid analysis of skeletal muscle from pigs susceptible to malignant hyperthermia

Previous studies demonstrated that lipid profiles of humans and pigs susceptible to malignant hyperthermia (MH) differ from those of normal humans and pigs. Lipid extraction techniques retaining in vivo lipid profiles most closely were used in the present study to determine if stimulation of lipolysis by the processes of homogenization or extraction might account for the reported differences in lipid profiles. No differences were observed among three genotypes of British Landrace pigs with respect to cholesterol levels, triglyceride levels, or total lipid phosphorus values of whole muscle (longissimus dorsi). Phospholipid distributions were the same for all three groups. Individual free fatty acids and fatty acids acylated to triglycerides were similar among the genotypes. These results do not support altered lipid profiles in vivo in MH-susceptible swine. Previously used homogenization and extraction procedures most likely affect the lipolytic activity to a different extent in muscle from MH-susceptible pigs and normal pigs.

Role of arachidonic acid and other free fatty acids in mitochondrial dysfunction in brain ischemia.

The aim of the present investigation was to evaluate the possible role of arachidonic acid and other free fatty acids in ischemia-induced mitochondrial dysfunction. Respiratory activities were measured in mitochondria isolated from rat brains subjected to 15-30 min of decapitation ischemia. Addition of bovine serum albumin (BSA) to the mitochondria, isolated in BSA-free media, abolished an ischemia-induced increase in substrate-stimulated (state 4) respiration but only partly reversed a marked inhibition of substrate-, phosphate-, and ADP-stimulated (state 3) respiration caused by the ischemia. Individual free fatty acids were measured in aliquots of the same mitochondrial preparations before and after treatment with BSA. There was a significant increase in arachidonic (20:4), stearic (18:0), palmitic (16:0), and docosahexaenoic (22:6) acid during ischemia. BSA treatment removed all 20:4 and reduced the amount of 18:0 and 16:0, but had no significant effect on 22:6. The main conclusions were 1) that 20:4, 18:0, and 16.0 were responsible for the partial uncoupling (increase in state 4 respiration) of mitochondrial respiration during ischemia, 2) that the inhibition of state 3 respiration caused by ischemia could only partly be attributed to an effect of FFAs, and 3) that the ischemia-induced mitochondrial dysfunction was caused by a combination of factors including 20:4.

Degradation of phospholipid molecular species during experimental cerebral ischemia in rats.

Previous investigators have shown that free fatty acids that accumulate during ischemia are an indicator of evolution in ischemic brain damage. Our study describes the temporal relations between free fatty acid accumulation and degradation of phospholipid molecular species after cerebral ischemia. Using the four-vessel occlusion model of adult Wistar rats, we analyzed quantitatively the cerebral phospholipid molecular species of diacyl phosphatidylcholine and diacyl phosphatidylethanolamine and released free fatty acids during ischemia. Total diacyl phosphatidylcholine molecular species decreased gradually but did not show any significant difference even at 60 minutes. By contrast, total diacyl phosphatidylethanolamine abruptly decreased after 5 minutes and continued to decrease significantly thereafter. Polyunsaturated molecular species showed a higher ratio of degradation than saturated and monounsaturated molecular species of either phosphatidylcholine or phosphatidylethanolamine. Total free fatty acid accumulated according to the time elapsed, and statistical significance was obtained after 10 minutes. Free arachidonic and docosahexaenoic acids were attributed to these significant accumulations at 10, 15, and 30 minutes. At 60 minutes, individual free fatty acids increased nonspecifically. Free fatty acids, which are hydrolyzed from phospholipid classes, are known to be further metabolized to bioactive substances such as prostaglandins and leukotrienes. Rapid degradation of phospholipid molecular species, especially of diacyl polyunsaturated molecular species, could be an important finding to membrane perturbation. Effective prevention of these changes might enhance tolerance to ischemic brain damage.

Gas chromatographic method for determining free fatty acids in cheese

A rapid gas chromatographic method for the analysis of individual free fatty acids (FFA) in cheese has been developed. Lipds were extract from a cheese paste acidified with diethyl ether and tetramethylammonium hydroxide (TMAM) was used for converting the FFA to TMA-soaps, which are transformed to methyl esters in the chromatographic injector. The effect of lactic acid was determined. The reproducibility of the method was studied and the coefficient of variation for the total FFA was found to be 2.2%. Recovery of individual FFA was in the range 87 to 106%.

Evaluation of free fatty acid kinetics during TPN feeding of healthy rats

Free fatty acid (FFA) kinetics were evaluated in TPN-fed healthy rats using a single fatty acid tracer. Rats were divided into three groups according to the nonprotein energetic substrate infused: glucose (A), monoacetoacetin-glucose (B), and lipid emulsion-glucose (C). Fat kinetics were measured by continuous infusion of [1- 14C]palmitate. Total FFA and individual FFA concentrations were measured and turnover and oxidation were determined for the total pool of FFA and for palmitate. Groups A and B were similar in all parameters. Group C had increased total and individual FFA concentrations. Group C appeared to have decreased total plasma FFA turnover and unchanged oxidation compared to groups A and B. Palmitate appeared to have a 400% increase in oxidation and a 50% increase in turnover for rats in Group C when compared to Groups A and B. It is concluded that a single tracer does not accurately reflect plasma FFA during TPN using lipid emulsion.

Growth Inhibition of Mastitis Pathogens by Long-Chain Fatty Acids

Staphylococcus aureus, Staphylococcus hyicus, Streptococcus agalactiae, and Corynebacterium bovis were tested for sensitivity to long-chain fatty acids predominant in teat canal keratin. Anti-bacterial activity of free fatty acids on each bacterial species was measured after 12 and 24h in chemically defined media. Polyene C18:2 and C18:3 acids were bactericidal to each species at ⩽105 ng/ml−1. The most bacteriostatic saturated fatty acids were C12 and C14. Streptococcus agalactiae growth was inhibited more by fatty acids after 24h than after 12h. No incubation time effect on growth responses of other species was determined. Polyoxyethylenesorbitan monooleate had a neutralizing effect on the bactericidal activity of polyene acids on C. bovis. Corynebacterium bovis were unable to grow in synthetic media containing individual free fatty acids as the sole source of preformed fatty acids. A relationship between bacterial species commonly isolated from bovine teat canals with resistance to fatty acids predominant in keratin was not evident.

Studies on the ripening of stilton cheese: Lipolysis

The levels of free fatty acids (FFA) in Stilton cheese showed very slight increases during the first 28 days, but they then increased rapidly up to the end of ripening. Some individual FFA, as mole percentages of total FFA, changed irregularly during ripening. Long-chain FFA were present at higher concentrations than were lower fatty acids. A relatively high level of carbonyl compounds, methyl ketones in particular, were present in Stilton during ripening. A good recovery of methyl ketones was obtained using a method based on reverse-phase high-performance liquid chromatography. The concentration of each methyl ketone did not depend on the level of available fatty acids. While the proportions of C 13 and C 15 ketones were relatively low compared with their precursor C 14 and C 16 fatty acids, the concentrations of C 7 and C 9 ketones were relatively high compared with their precursor C 8 and C 10 fatty acids. With the exception of C 7 and C 9 ketones, which showed consistent and considerable increases up to the end of ripening ( C 7 + C 9 accounted for 60% of total methyl ketones), the relative concentrations of methyl ketones fluctuated during ripening; this is probably the result of interconversions of the methyl ketones and/or their reduction to secondary alcohols.

High-performance liquid chromatographic analysis of serum long-chain fatty acids by direct derivatization method

A new visible-ultraviolet labelling method for the high-performance liquid chromatographic analysis in serum of individual free fatty acids, including polyunsaturated fatty acids, is described. Without commonly used isolation steps, fatty acids in serum were directly derivatized by treatment with acidic 2-nitrophenylhydrazine hydrochloride. The derivatized fatty acids were extracted into n-hexane and separated isocratically on a reversed-phase C 8 column within 15 min. The detection limits ranged from 400 fmol to 1 pmol and from 100 to 200 fmol per injection with visible and ultraviolet detection, respectively. Visible detection had better selectivity, and free fatty acid levels were determined in sera obtained from healthy controls and patients with diabetes mellitus. In all the subjects studied, the precise quantitation could be performed with 25 μl of serum. Analytical recoveries ranged from 98.3 to 103.4%. The intra- and inter-assay coefficients of variation were less than 2.7 and 3.5%, respectively. The present method is superior to the previously published methods for routine analyses: it is cheaper, the procedure is simpler, the analysis time is shorter and both resolution and sensitivity are better.

Determination of Individual Free Fatty Acids in Milk by Strong Anion-Exchange Resin and Gas Chromatography

A quantitative method for determination of free fatty acids in milk is described. Free fatty acids and some glycerides were extracted from milk in acetonitrile in the presence of sulfuric acid and anhydrous sodium sulfate. The filtered extract was evaporated to dryness. With use of strong anion-exchange resin as heterogenous basic catalysts, the free fatty acids were methylated directly. The free fatty acids were separated by gas chromatography with a 2000 mm×2-mm inner diameter glass column packed with 10% SP-2330 on 100/120 mesh Chromosorb W.

The transfer of free fatty acids across the human placenta.

Thirty-three matched maternal venous and umbilical cord vein and artery plasma samples were obtained at elective caesarean section and the concentrations of the individual free fatty acids determined. The maternal levels were 1.009 (SEM 0.043) and the umbilical vein-artery difference was 0.036 (SEM 0.011) mmol/l. There was a significant correlation between the mean concentration in maternal venous blood and the vein-artery difference for myristic, palmitic, stearic, linoleic and docosahexaenoic acids but not for oleic acid. When arachidonic acid concentration in the fetus was high, then the vein-artery difference was negative (flow to the placenta), when it was low, the difference was positive (flow to the fetus). Thus whilst there appears in general to be a flow of fatty acid to the fetus dependent on maternal free fatty acid concentrations, the transfer of arachidonic acid is largely determined by other factors. The reasons why oleic acid does not behave like the other fatty acids is not clear.

Total and individual free fatty acid concentrations in liver cirrhosis

The finding of high plasma free fatty acid (FFA) levels in cirrhotic patients has been attributed either to decreased hepatic clearance or to enhanced fat mobilization. To better clarify these hypotheses, total and individual FFA and glycerol levels were determined in 21 cirrhotic patients with different degrees of hepatocellular damage (evaluated by liver function tests), portal hypertension (evaluated by endoscopy and clinical signes), and nutritional status (evaluated by anthropometric and biohumoral parameters) and in 10 age- and sex-matched healthy subjects. Glucose tolerance and insulin and glucagon levels were determined in all individuals. Well-nourished and malnourished patients were identified within the cirrhotic group. Plasma FFA and glycerol concentrations were well correlated (r = 0.47, P < 0.05), levels being significantly higher in cirrhotic individuals than in controls (746.6 ± 46.29 SE v 359.22 ± 40.82 μmol/L, P < 0.001 for plasma FFA; 150.1 ± 3.12 v 82.5 ± 9.2 μmol/L, P < 0.01) for glycerol). Plasma FFA and glycerol showed no correlation with the liver function test results or portal hypertension parameters. Interestingly, plasma levels of FFA and glycerol were influenced by the nutritional status, significantly higher FFA levels being observed in the well-nourished than in the malnourished patients (842.5 ± 47.5 v 563.4 ± 78 μmol/L, P < 0.005). Furthermore, a positive correlation was found between plasma glycerol level and percentage of triceps skinfold ( r = 0.45, P < 0.05). No correlation was found between plasma levels of FFA or glycerol and glucose tolerance, insulin and glucagon. So far the individual FFA patterns are concerned, a significant percentage decrease was observed in palmitic and stearic acid levels and a significant percentage increase in palmitoleic and oleic acid levels in the cirrhotic group, no difference being found between well-nourished and malnourished patients. In conclusion, the high plasma FFA and glycerol levels in patients with liver cirrhosis do not appear to depend on the degree of liver damage or portal hypertension, but rather are due to enhanced lipolysis. Fat mobilization appears to decrease as malnutrition advances.

Free fatty acid content and release kinetics as manifestations of cerebral lateralization in mouse brain.

Free fatty acid (FFA) content was analyzed in mouse cerebral hemispheres and cerebellum under basal and postdecapitative ischemic conditions. Total FFA content immediately after decapitation (2 s) was about two-fold higher in the left hemisphere than in the right. Marked dissimilarities between hemispheres were also apparent when FFA levels were measured during short periods of ischemia. Whereas in the right side a significant FFA release took place as early as 10 s, no accumulation was detected in the left in the 2-20 s interval. The highest rates of total fatty acid release occurred in the 20-30 s interval in both hemispheres and decreased afterwards (3 min). Individual FFA, especially stearate and arachidonate, differed in their rates of production, the right cerebral hemisphere being more active in releasing arachidonic acid. In cerebellum, FFA levels were lower and accumulation was slower than in cerebrum in both intervals. When subjected to 3 min ischemia, the same difference in FFA levels between right and left hemispheres (50%) was observed in heads kept at 20 or 30 degrees C. The differences between hemispheres are interpreted as manifestations of an inherent lateralization in the regulation of acylation-deacylation reactions of complex lipids.

Modified Techniques for Improved Gas Chromatographic Quantification of Free Fatty Acids in Dairy Foods

Modified techniques for improved routine gas chromatographic quantification of individual free fatty acids include the use of diethylene glycol succinate columns, incorporation of a carbon-9 free fatty acid internal standard, removal of excess water from free fatty acid isolates and gas chromatographic systems, and exclusion of chemical contaminants from free fatty acids isolates.

Concentrations of Major Free Fatty Acids and Flavor Development in Italian Cheese Varieties

Major individual free fatty acids in commercial samples of four Italian cheese varieties were measured during aging at 2 or 7°C. Romano cheeses had the greatest amounts of free fatty acids and the strongest free fatty acid flavors. Concentrations of carbons 4 and 6 free fatty acids decreased, whereas those of carbons 14 to 18 increased during latter stages of aging. Full flavored, aged Parmesan cheeses contained only moderate amounts of major free fatty acids, and after initial development, concentrations remained essentially constant during further aging. Higher flavor intensities but variable flavor qualities were associated with higher free fatty acid concentrations in Provolone cheeses through 7 mo of aging at 2 or 7°C. Mozzarella cheeses had low free fatty acid concentrations and mild flavors, and except for carbon 4, a role for free fatty acids in the characteristic flavor of this cheese was not apparent. Analysis of retail Italian cheeses in the same varieties showed great variability of concentrations of individual major free fatty acids, flavor intensity, and flavor quality.

Quantification of Major Free Fatty Acids in Several Cheese Varieties

Low to moderate concentrations of individual major free fatty acids were in Camembert, Brie, Port Salut, Monterey Jack, Edam, Colby, and Gruyere cheeses. Blue and Roquefort cheeses had high free fatty acid contents and strong flavor of free fatty acids. Goat's milk cheese had high 8-carbon free fatty acids. Limburger cheese had high concentrations of 4-carbon and 6-carbon, but flavor contributions from these free fatty acids were suppressed because the pH of this cheese was high (6.97). Hydrolytic rancidity flavor defects in Swiss, Brick, and Cheddar cheeses were signaled by measurement of high concentrations of individual short-chain free fatty acids.

Stimulation of prostaglandin E2 synthesis by exogenous phospholipase A2 and C in rabbit kidney medulla slices.

We have investigated the effects of phospholipase A2 and C on the synthesis of prostaglandin E2 in rabbit kidney medulla and the release of fatty acids from the medulla slices. Exogenous phospholipase A2 [from Naja naja (Indian cobra) venom] and phospholipase C (from Clostridium welchii) stimulated prostaglandin E2 production in a dose-dependent manner. At the maximal effective concentrations (0.5 unit of phospholipase A2/ml, 2 units of phospholipase C/ml), phospholipase C increased prostaglandin E2 formation to the level observed with phospholipase A2. Phospholipase A2 enhanced the release only of unsaturated fatty acids, whereas phospholipase C stimulated the release of individual free fatty acids (C 16:0, C 18:0, C 18:1, C 18:2 and C 20:4). Moreover, p-bromophenacyl bromide inhibited phospholipase A2-stimulated prostaglandin E2 production and the release of fatty acids, but it had no influence on prostaglandin E2 formation and the release of fatty acids increased by phospholipase C, indicating that the stimulatory effect of phospholipase C is not mediated through the activation of endogenous phospholipase A2. These results suggest the presence of diacylglycerol lipase and monoacylglycerol lipase in the kidney and the importance of this pathway in prostaglandin synthesis by the kidney.

トレーニングが血中及び脂肪組織の脂肪酸構成比にあたえる影響

The purpose of the present study was to investigate the influence of training on the metabolism of plasma free fatty acid (FFA), and fatty acid (FA) composition of plasma FFA and adipose tissue triglyceride (TG). The results are summarized as follows: 1) There were no significant differences between pre- and post-training values in the total plasma FFA. 2) Among the individual FFA at rest, the percentage of saturated FA increased and unsaturated FA decreased as a result of physical training. 3) Comparing trained group with untrained group, similar differences were observed in FA composition of plasma FFA and the adipose tissue TG. There were higher percentage of saturated FA and lower percentage of unsaturated FA in the trained group. The above resluts suggested that FA pattern and FA metabolism of plasma and adipose tissue are changed under the influence of physical training.