Fatty Acid Composition Of Lecithin Research Articles

Structured phosphatidylcholine with elevated content of conjugated linoleic acid: Optimization by response surface methodology

AbstractStructured phosphatidylcholine was successfully produced by immobilized phospholipase A1 catalyzed acidolysis of phosphatidylcholine and CLA. Response surface methodology was applied to optimize the reaction system using three process parameters: enzyme load, temperature, and substrates molar ratio. Optimal conditions obtained from the model were 15% enzyme load at 55°C for a 1:4 (PC/CLA) substrates molar ratio, which produced a yield of 85.8% of CLA incorporation. The total correlation coefficient (R2) was 0.92 and no lack of fit was detected. This suggests the fitness of the model obtained and it suggests that the model is sufficiently accurate to estimate the incorporation of CLA into PC.Practical applications: This study could contribute to process development for enzyme catalyzed phospholipid modification. By changing the fatty acid composition of lecithin, delivery of desired (beneficial) fatty acids could be better achieved. Additionally, emulsification properties of the phospholipids could open a wide area of applications in the food and cosmetic industries.

Fatty acid composition of amniotic fluid lecithin and its relationship to amniotic fluid C-peptide in diabetic pregnancy.

Fatty acid composition in lecithin and C-peptide was analysed in amniotic fluid samples obtained from 28 normal and 24 insulin-treated diabetic women in the 34th to 39th week of pregnancy. The pattern of changes of fatty acid composition of amniotic fluid (AF) lecithin was essentially the same in pregnancies complicated by diabetes as in non-diabetic controls. However, at 36/37 weeks, the mean values for palmitoleic acid (16:1) were statistically higher in diabetic women (P less than 0.02), and the mean values for stearic acid (18:0) were higher for normals (P less than 0.02). The mean C-peptide value was more than twice as high (0.71 nmol/l) in the diabetic group than in the control group (P less than 0.01). The lecithin/sphingomyelin (L/S) and palmitic/stearic acid (P/S) ratios were equal in both groups. Neither in five diabetic patients with fetuses indicating marked hyperinsulinism (C-peptide greater than 1.0 nmol/l) nor in the remaining group of patients was there any relationship between C-peptide levels and the lecithin fatty acid composition.

Fatty acid composition of lecithin is a key factor in bile metastability in supersaturated model bile systems

We studied the effect of fatty acid saturation of biliary lecithin on bile metastability, determined by nucleation time, using model bile solutions with identical lipid compositions except for the lecithin species (total lipid concentration, 9 g/dl; cholesterol, 12 mM; lecithin, 31 mM, bile salts, 116 mM). Gel permeation Chromatographic studies revealed that nonmicellar cholesterol distribution was inversely related to the degree of unsaturation of the lecithin species. Differential interference contrast microscopy and cholesterol crystal growth assay showed that a lower degree of saturation of the lecithin species was associated with a faster nucleation time and crystal growth rate. These results suggest that vesicular lecithin containing more unsaturated fatty acyl chains binds less tightly to cholesterol as compared with lecithin containing predominantly saturated fatty acids and that the biliary lecithin species modulates cholesterol crystal nucleation in bile. Also, the high ratio of cholesterol to lecithin (more than 1.0) was found in the crystal forming model biles, although the vesicle aggregation was not always observed prior to the cholesterol crystal formation. These findings indicated that there are different processes in cholesterol crystal nucleation, with or without vesicle aggregation, and that such processes depend, in part, on lecithin species in vesicles.

Nucleation time and fatty acid composition of lecithin in human gallbladder bile.

We investigated the relationship between bile nucleation time and the fatty acid composition of biliary lecithin in human gallbladder bile. Bile samples from patients with cholesterol gallstones nucleated more rapidly than those from patients with noncholesterol gallstones or no stones. The biliary cholesterol concentration was highest in the cholesterol gallstone group and was correlated with the molar percentage of linoleic acid and arachidonic acid, with these percentages also being higher in bile from the cholesterol gallstone patients than in bile from the other two groups. In addition, the mucous glycoprotein concentration in bile was also significantly higher in the cholesterol gallstone group. Thirty-three patients in the no-stone group showed bile nucleation times of less than 21 days. Higher concentrations of cholesterol and mucous glycoprotein and higher molar percentages of arachidonic and linoleic acid were noted in these patients. These findings suggest that in humans, hepatic cholesterol hypersecretion is associated with the increased unsaturated fatty acid proportion in biliary phospholipids and gallbladder mucin hypersecretion, thereby causing rapid cholesterol crystal nucleation.

Essential fatty acids in pregnancies complicated by intrauterine growth retardation

The relative fatty acid composition of lecithin was measured in maternal and cord blood serum in human pregnancies at risk for intrauterine growth retardation (IUGR) (n = 28) as compared to controls (n = 20). In the IUGR cases (n = 13) linoleic acid was lower in maternal samples but higher in cord blood, oleic acid was elevated in both whereas docosohexaenoic acid was lower. Essential fatty acid composition of lecithin was found to be different in IUGR.

The influence of copper intrauterine device on fatty acid composition of cervical mucus lecithin

Fatty acid composition of lecithin was analysed in midcycle cervical mucus obtained from 19 women using a copper intrauterine device (Cu-IUD) and 16 controls. In both groups, palmitic (16:0) acid was the predominant fatty acid and oleic (18:1) acid the second largest component. In women using a Cu-IUD, levels of myristic (14:0) acid were significantly lower, while levels of linoleic (18:2) and docosahexaenoic (22:6) acid were significantly higher than in controls. These changes in fatty acid composition could not be related to duration of IUD use and were very similar to those observed in women with primary unexplained infertility, suggesting that the Cu-IUD-induced modification of fatty acid pattern in midcycle mucus lecithin may be part of the contraceptive mechanism of action.

The influence of gonadal steroids and the pituitary on the levels and composition of plasma phospholipids in the rat

Gonadal steroids have been shown to influence plasma phospholipids. In the present study, the possible interaction between gonadal steroids and the pituitary in the regulation of plasma phospholipids was studied in rats. The total phospholipid concentration (higher in females) and the fatty acid composition of plasma lecithin was different in male compared to female rats. Gonadectomy resulted in a “feminization” of plasma phospholipids (total concentration and fatty acids in lecithin) in male rats but had no effect in females. Testosterone treatment of gonadectomized males or intact females resulted in a “masculinization” of plasma phospholipids, whereas estrogen treatment of intact males resulted in a “feminization.” Hypophysectomy resulted in a marked decrease in plasma phospholipid concentration and the fatty acid composition of lecithin showed a “masculine” pattern in both males and females. Neither testosterone nor estrogen treatment had any effects on plasma phospholipids in hypophysectomized male and female rats, respectively. It is concluded that gonadal steroids and the hypothalamic-pituitary axis interact in the regulation of the synthetic and perhaps also degradative pathways controlling plasma phospholipids.

Lipid metabolism in women with polycystic ovary syndrome: possible implications for an increased risk of coronary heart disease

This study reports values of serum lipids, lipoproteins, and the relative fatty acid composition of lecithin and cholesterol ester in 20 women with typical polycystic ovary syndrome (PCO). These values were compared with values of 22 regularly menstruating women without clinical evidence of androgen excess. Higher levels of triglycerides in serum (P less than 0.05) and very low-density lipoproteins (P less than 0.01) and lower concentrations of free cholesterol in low-density lipoproteins (P less than 0.05) were found in the PCO women. In serum lecithin the PCO patients had higher palmitic and lower stearic acid levels compared with those of the normal women. This finding was interpreted as a reduction of the excretory capacity of the liver in the PCO group. No correlations between lipids and sex hormones were found. Body weights and blood pressures were higher in the PCO group. The results indicate that PCO women could be at increased risk for coronary heart disease, because an increased serum triglyceride level, body weight, and blood pressure are considered to be risk factors of coronary heart disease.

Influence of esterified estrogens and medroxyprogesterone on lipid metabolism and sex steroids. A study in oophorectomized women.

Eight oophorectomized women were given 1.25 mg esterified estrogens (EE) daily for 21 days and 5 mg medroxyprogesteroneacetate (MPA) daily for 5 days in a sequence combination. The effects on sex steroids, gonadotrophins, lipids and lipoproteins as well as the relative fatty acid composition of lecithin and cholesterol ester induced by treatment were studied. Esterified estrogens were readily absorbed with estrogen levels corresponding to those of a normal luteal phase. A favourable estrone/estradiol ratio was found during treatment. After two days without EE no estrogens could be detected. Androstenedione was significantly depressed after the MPA period, otherwise it remained unchanged. Minor changes were induced in serum lipids and lipoproteins. A decrease in cholesterol ester of 12 and 23 per cent was found for palmitic and stearic acid concomitant with an increase of arachidonic acid of about 20 per cent after three weeks of estrogen treatment. After the MPA period increases in free cholesterol, total cholesterol and phospholipids in HDL were assessed. It was concluded that MPA in this experiment from a lipid metabolic point of view seemed to be a favourable progestogen complement.

Study on Effect of 30 μg Ethinylestradiol (Ee)+150 μg Desogestrel on Lipid and Lipoprotein Metabolism in Healthy Volunteers, Also in Comparison with 30 μg Ee + 150 μg Levonorgestrel

Abstract. In a cross‐over design study, 15 healthy young volunteers were randomly allocated an oral contraceptive containing 30 μg EE. Preparation A contained in addition 150 μg of a new progestogenic compound, desogestrel, and preparation B 150 μg levonorgestrel. Subjective side effects were few during use of any of the preparations.Preparations A and B induced similar changes in most of the serum lipid and lipoprotein‐lipid parameters. Body weight, triglycerides, VLDL‐triglycerides and LDL‐free cholesterol, total cholesterol and triglycerides were significantly lower and HDL‐total cholesterol and triglycerides significantly higher with preparation A than preparation B.The relative fatty acid composition of lecithin revealed with preparation B (as compared with preparation A), higher levels of palmitic and linoleic acids which could be interpreted as an enhancement of pathway I for liver lecithin synthesis which in turn is usually coupled to a reduced capacity of liver excretory function.The present data regarding preparation B are in agreement with those reported by others, while preparation A has not been studied before. The differences observed between preparation A and B are ascribed to the more marked androgen‐like effects of preparation B.

Terbutaline and pulmonary surfactant release in the rabbit fetus.

The influence of terbutaline on content of phospholipids and their fatty acid composition in fetal lung wash and lung homogenates was studied in 28-day-old rabbit fetuses. To obtain both the fatty acid composition and the quantity of lecithin and sphingomyelin gas-liquid chromatography (GLC) was used, which gave a linear relationship when compared to standard solutions of the phospholipids. The amount of lecithin was significantly increased in the lung wash in terbutaline-treated fetuses compared to controls, while the sphingomyelin content was unchanged. In the lung homogenates no quantitative differences were noted between the two groups. The fatty acid composition of lecithin and sphingomyelin did not alter neither in lung wash nor in lung homogenate after terbutaline administration. The present results indicate that beta-mimetics mainly act by favouring the release of preformed surfactant and not by stimulating the synthetic capacity of type II cells in the alveolar lining layer.

Fatty acid composition of serum lecithin in healthy children

Serum concentrations of cholesterol, triglycerides, phospholipids and the fatty acid composition of lecithin were determined in 107 children aged 1–15 years. The major aim of the study was to find out the normal ranges of the proportions of the essential fatty acids in lecithin for further studies of nutritional and metabolic disorders. The population contained partly children admitted for general anaesthesia, partly healthy school children. The series was considered to be representative of normal children of the ages in question.

Lipid metabolic studies in oophorectomized women. Effects induced by the addition of norethisterone acetate to two different oestrogens on serum individual phospholipids and serum lecithin fatty acid composition.

Abstract. Norethisterone acetate (NET) was administered to 11 oophorectomized women (mean age 34.5 ± 5.9 years) primed with the 17-C-alkylated ethinyl oestradiol (EOe) and the non-alkylated oestrogen, oestradiol valerate (Oe2V) in separate periods. Blood samples were drawn after 4 weeks without hormonal replacement therapy, after 6 weeks on each oestrogen and after 6 weeks on each oestrogen-progestogen combination. Routine liver function tests were carried out, assessment of individual phosholipids i.e. cephalin, lecithin, lysolecithin and sphingomyelin was done after thin layer chromatography. The relative fatty acid composition of serum and high density lipoprotein lecithin and serum cholesterol ester was determined by gas liquid chromatography. The redistribution of serum individual phospholipids (increase in lecithin and decrease in lysolecithin) induced by both oestrogens was reversed by the addition of NET. This lecithin-lysolecithin shift seen after NET administration could depend on a stimulation of the hepatic lipase with its phospholipase Al-activity. The 17-C-alkylated EOe, but not the non-alkylated Oe2V, caused an increase in palmitic and a decrease in stearic acid in the 1-position of serum lecithin. When NET (like EOe, 17-C-alkylated) was added to EOe, this palmitic-stearic acid shift was further accentuated, and it also appeared when NET was added to Oe2V. It is suggested that the shift in 1-position fatty acids of serum lecithin induced by EOe and NET is a non-hormonal 'drug-effect' linked to their 17-C-alkylation and liver toxicity. The reduction in arachidonic acid of serum lecithin and serum cholesterol ester seen after NET administration is interpreted as an anti-oestrogenic effect which could be mediated by a decreased transformation of linoleic to arachidonic acid in the liver.

Effects induced by two different estrogens on serum individual phospholipids and serum lecithin fatty acid composition.

Eleven oophorectomized women (mean age 34.5 +/- 5.9) received two treatment cycles, one of the 17-C-alkylated ethinyl estradiol 20 microgram per day, and the second of the non-alkylated estrogen, estradiol valerate 2 mg per day for six weeks in separate periods preceded by six weeks without hormonal replacement therapy. Blood samples were drawn before and after six weeks on each estrogen. The samples were assayed for individual phospholipids i.e. cephalin, lecithin, lysolecithin and sphingomyelin after separation of these lipids by thin layer chromatography. The relative fatty acid composition of serum and high density lipoprotein lecithin and serum cholesterol ester was determined by gas liquid chromatography. Both estrogens reversed the symptoms of estrogen deficiency and had similar effects on serum individual phospholipids i.e. causing an increase in lecithin concomitant with a decrease in lysolecithin. It is suggested that this lecithin-lysolecithin shift could depend on an inhibition of the hepatic lipase and its phospholipase A1-activity. Both estrogens increased serum lecithin arachidonic acid without causing any change in linoleic acid (the major essential fatty acid), which indicates that this increase in arachidonic acid could be an estrogenic effect independent of dietary factors. Ethinyl estradiol caused an increase in palmitic and a decrease in stearic acid in the 1-position of serum lecithin while estradiol valerate did not influence these fatty acids at all. This palmitic-stearic acid shift induced by ethinyl estradiol is interpreted as a non-hormonal "drug-effect" linked to the liver toxicity of 17-C-alkylated steroids in spite of the lack of influence on routine liver function tests.

Radiation-induced changes of liposomes and lecithin in non-aqueous media.

Radiation-induced changes of lipids in non-aqueous media were studied to elucidate the process of radiation damage in biological membranes. The lipid peroxidation progressed linearly with increasing dose and decreasing dose rate of gamma-irradiation in soyabean lecithin in chloroform. The fatty acid composition of lecithin also changed, especially in linoleic and linolenic acids. Lower dose rate radiation enhanced these changes in oxic condition. Lipid peroxidation was also shown in lipids extracted from irradiated liposomes or in liposomes prepared from irradiated lecithin in chloroform. The dose-dependent glucose efflux was seen in liposomes prepared from irradiated lecithin in chloroform. These results indicate that the peroxidation of lipid molecules might cause radiation damage to the membrane conformation.

Administration of dehydroepiandrosterone enanthate to oophorectomized women - effects on sex hormones and lipid metabolism

Eight bilaterally oophorectomized women were given a depot injection of 200 mg DHEA-enanthate to study the effect on endocrine and lipid metabolism. A decrease in sex-hormone binding globulin (SHBG) and an increase in androstenedione was found 14 and 30 days after the injection. No changes could be detected in LH, FSH, oestrone, oestradiol or oestriol. Testosterone showed a tendency towards an increase. As compared to pre-treatment values, plasma lipids were unaltered after 30 days. A decrease in high density lipoproteins (HDL), cholesterol and in very low density lipoproteins (VLDL), free cholesterol, total cholesterol and phospholipids were seen in the lipid composition of the lipoproteins on day 30. These findings are in agreement with previous data reported after the administration of drugs with androgen-like effects. The relative fatty acid composition of plasma lecithin revealed only minor changes while the fatty acid composition of cholesterol esters indicated a decreased portion of essential fatty acids. These results suggest, in agreement with previous studies, an impaired endogenous cholesterol formation in the liver. The results from the analysis of the fatty acid composition of lecithin and cholesterol esters might indicate a decreased percentage of exogenous (dietary) cholesterol ester in plasma.

The influence of paraquat on the in vivo incorporation of lecithin precursors in lung tissue and 'alveolar' lecithin.

Rats were injected with paraquat (1,1'-dimethyl-4,4'-bipyridyliumdichloride, 35 mg/kg) and killed 14 or 48 h later. Twelve hours prior to sacrifice labelled choline or palmitic acid was injected. Immediately after sacrifice alveolar lavage was performed in situ and the lungs were removed and homogenized. Lipid extracts from lavage fluid and lung homogenates were prepared and their lecithin content analysed by thin layer chromatography. Lecithin was quantitated by phosphorous determination, the incorporation rate of the lecithin precursors in 'alveolar' and lung tissue lecithin was measured by liquid scintillation, and the fatty acid composition of lecithin was determined by gas liquid chromatography. In comparison with controls, the content of lecithin was reduced in lavage fluid from paraquat-injected rats. These animals also had reduced incorporation of choline in alveolar lecithin. The rate of incorporation of palmitic acid was the same in experimental animals and controls, so was the incorporation of choline in lung tissue lecithin. The findings suggest that paraquat interferes with the synthesis of alveolar lecithin by the phosphocholine transferase pathway, but not with the formation of lung tissue lecithin.

Effect of a sequential oestrogen-progestin therapy on the plasma level of oestrogens and lipids in post-menopausal women.

ABSTRACT With the aim of minimizing side effects of substitution therapy a natural synthetic oestrogen, oestrone sulphate, and norethisterone acetate were administered to 6 oophorectomized women and 4 women with physiological menopause cyclically in order to follow the pattern of physiological variations during the menstrual cycle as closely as possible, without causing bleedings. In addition to assessing the clinical effects and analyses of plasma oestrone and oestradiol-17β, the metabolic effects on plasma triglycerides, cholesterol and individual phospholipid levels, as well as on the fatty acid composition of lecithin were followed. The oral administration of oestrone sulphate in doses varying with the "cycle" from 0.5 to 1.5 mg/day gave in these women plasma concentrations of oestrone in the lower pre-menopausal physiological range causing cyclic variations in plasma lipids similar to those during a physiological menstrual cycle but did not normalize the plasma oestradiol concentrations and did not give acceptable therapeutic effect. Total phospholipids, total and free cholesterol, triglycerides and the percentage of lecithin were higher, and the percentage of lysolecithin lower in the oestrogen phase, than in the progestin phase. The changes in linoleic acid in lecithin varied inversely with changes in arachidonic acid in lecithin and cyclic variations also occurred in the content of palmitic and stearic acid in lecithin. When previous treatment with ethinyloestradiol was exchanged with oestrone sulphate the total cholesterol values in plasma varied in the opposite direction. The results obtained in this and previous studies suggest different effects of ethinyloestradiol and oestrone (oestrone sulphate?) in the metabolism of certain sterols, and that the effect of oestrone (or oestrone sulphate?) on plasma cholesterol dominates during physiological condition in the follicular phase of the menstrual cycle.

Lecithin : cholesterol acyl transfer (LACT) and fatty acid composition of lecithin and cholesterol esters in young male myocardial infarction survivors

Lecithin : cholesterol acyl transfer (LCAT) and relative fatty acid composition of serum lecithin and cholesterol esters were studied in 20 young male survivors of myocardial infarction (MI). Comparisons were made with controls matched for serum cholesterol. There was no difference in LCAT rate between MI patients and controls. The relative content of arachidonic acid in cholesterol esters was higher in MI patients. The fatty acid composition of lecithin and cholesterol esters suggests an equal transfer of linoleic and oleic acids from lecithin to cholesterol. Furthermore negative correlations were found between LCAT and linoleic acid content of lecithin ( r = −0.43, P < 0.01) and cholesterol esters ( r = −0.45, P < 0.01). This inverse relationship does not seem to be linked to substrate specificity, but rather to be mediated by influences in common on serum lipid content and turnover.

Mechanism for lipid abnormalities of erythrocyte membranes in biliary obstruction: Lecithin content and its fatty acyl composition

The lipid compositions of erythrocyte membranes, plasma and bile of 16 patients with biliary obstruction were analysed to obtain information regarding the origin of excess lecithin which is usually found in the erythrocyte membranes in obstructive jaundice. Phospholipids and free cholesterol were found to be increased proportionally to the degree of biliary obstruction with an elevation in the free cholesterol/phospholipid ratio in the red cell membranes. The increase in phospholipid content is primarily due to lecithin. There was a highly significant alteration in the fatty acid composition of lecithin of erythrocyte membranes, plasma and bile from patients with severe jaundice. Red cell membrane lecithin amounted to more than 40% of the total phospholipid in these patients. Interestingly, the fatty acid composition of lecithin showed a similar pattern in erythrocyte membranes, plasma and bile. In addition, the fatty acyi chain composition of lecithin in lipoprotein-X was very similar to that of the red cell membrane. Freeze-fracture electron microscopy showed an alteration in membrane morphology and a reduced number of membrane-associated particles in the fractured faces. From these findings, we suggest that the lecithin of lipoprotein-X is derived from abnormal bile lecithin, which is incorporated into erythrocyte membranes by fusion with lipoprotein-X. On the other hand, the fatty acid composition of bile lecithin from patients with mild jaundice, whose erythrocyte membrane lecithin amounted to less than 31% of total phospholipid, was not different from that of normal individuals. However, in sharp contrast to the bile content, the fatty acid composition of erythrocyte membranes and plasma in these same patients showed a similar but small change compared to that of patients with severe biliary obstruction. The red cells of patients with mild jaundice were almost normal, biconcave disc-shaped, as observed by scanning electron microscopy and no abnormalities in the distribution or number of membrane particles were detected by freezefracturing. We propose that the abnormal lecithin content of erythrocyte membranes in patientd with mild jaundice can be explained by the gradual exchange of lecithin between red blood cells and plasma lipoprotein.