Acid Composition Of Serum Lecithin Research Articles

Relative Fatty Acid Composition of Serum Lecithin in Perimenopausal Women Using Combined Hormone Replacement Therapy

Objective: The atherogenicity of low-density lipoproteins (LDLs) is greatly enhanced when LDL is modified, particularly by oxidation. Experimental data as well as studies in rabbits and monkeys suggest an anti-oxidant effect of estrogens that results in reduced formation of oxidized LDL. Oxidized LDL in plasma is rapidly cleared from the circulation by means of scavenger receptors, and it is difficult to demonstrate direct changes using plasma samples only. The oxidative potential for the formation of oxidized LDL is derived from the polyunsaturated fatty acids of the phospholipid lecithin. For example, an increase in the relative content of linoleic and arachidonic acids in serum lecithin could tentatively be regarded as a decrease in the formation of oxidized LDL. Design: Forty perimenopausal women were given continuous hormone replacement therapy (HRT) consisting of 2 mg of estradiol daily. After random allocation, levonorgestrel comedication was given as 0.250-mg tablets for 10 days per cycle or was continuously released (0.02 mg/d) from an intrauterine device (IUD). The relative fatty acid composition of serum lecithin was determined by gas-liquid chromatography using a capillary column equipped with a flame ionization detector and a computerized identification system based on retention times. Results: Polyunsaturated acids in serum lecithin were augmented by both regimes with negligible differences between the oral and the IUD group. Conclusions: The present results indicate that estradiol in combination with either oral cyclical or continuous-release levonorgestrel inhibits formation of oxidized LDL.

The relative fatty acid composition of serum lecithin and cholesterol ester: Influence of an estrogen-progestogen regimen in climacteric women

The relative fatty acid compositions of serum lecithin and cholesterol ester were studied during continuous treatment with an estrogen/progestogen combination. All 26 women who participated suffered from climacteric complaints and were given one tablet daily containing 2 mg of 17 β-estradiol, 1 mg of estriol, and 1 mg of norethindrone acetate. Blood samples were taken before treatment and after 3 and 12 months of treatment. In serum lecithin, a decrease (p < 0.01) in stearic acid concomitant with an increase of linoleic (p < 0.05) and arachidonic (p < 0.01) acids was recorded. The most evident changes noted in cholesterol ester were decreased levels of stearic (p < 0.01), oleic (p < 0.05), and arachidonic (p < 0.001) acids. Polyunsaturated acids of the n-6 series are precursors for prostaglandins and leukotrienes. In the present study an increase of dihomo-γ-linolenic, linoleic, and arachidonic acids in serum lecithin was found after treatment, and theoretically this finding may have an impact on the prostacyclin-thromboxane balance.

High-dose depot-medroxyprogesterone acetate—Effects on the fatty acid composition of serum lecithin and cholesterol ester

Twenty-one women were treated with high doses of depot-medroxyprogesterone acetate (1000 mg/week im) for 6 months as part of the treatment of endometrial carcinoma. The relative fatty acid composition of serum lecithin and cholesterol ester were analyzed. In previous studies low doses of medroxyprogesterone acetate (MPA), in contrast to progestins of the 19-nor-testosterone series, have been shown not to affect the fatty acid composition of serum lecithin and cholesterol ester. However, the high doses of MPA used in this study increased linoleic acid and decreased arachidonic and di-homogammalinolenic acids in serum lecithin. The ability of a steroid to induce this shift has been ascribed to its androgenicity. MPA is considered to have weak, if any, such properties. The findings of this study emphasize the necessity to delineate effects on metabolism of different doses and administrative routes of any particular steroid.

The fatty acid composition of serum lecithin after pregnancy complicated by pre-eclampsia.

Using gas-liquid chromatography the relative fatty acid composition of serum lecithin was measured in 22 women, during and after pregnancies complicated by pre-eclampsia, and the results were compared with those in 21 "normal" puerperal women. The increased values of 22:6 in the linolenic acid series found during pregnancy in women who had pre-eclampsia were also noted in the puerperium and the 22:6 value fell to normal more slowly. This might be due to an enhanced activity of the deacylation-reacylation cycle in this group of patients. All other fatty acids showed a rapid return to normal with values comparable to those of "normal" puerperal women 1 week after delivery. The differences in essential fatty acid distribution between normal and pre-eclamptic women did not seem to have a dietary cause. The prostaglandin precursors (arachidonic and dihomo-gamma-linolenic acids) were not reduced during pre-eclampsia or in the puerperium. Neither breast-feeding nor treatment of hypertension with hydralazine seemed to influence the fatty composition of serum lecithin.

Relative fatty acid composition of serum lecithin in the normal puerperium.

21 women who had been followed regularly during their normal pregnancies were examined in the puerperium. The relative fatty acid composition of serum lecithin was analyzed by means of gas-liquid chromatography. Palmitic acid decreased and stearic acid increased, which indicates a shift to more pathway II-synthesized lecithin in the puerperal period. Linoleic acid increased and the longer polyunsaturated fatty acids decreased. These changes were slow as compared to the changes in the saturated fatty acids. No correlations were found between the saturated fatty acids and linoleic acid dominating the polyunsaturated fatty acids. The results indicate different incorporational ways into the lecithin molecule of these fatty acid groups. It is suggested that the deacylation-reacylation cycle is responsible for the high content of longer polyunsaturated fatty acids still 1 week after delivery. 6 weeks after delivery normal values were recorded. Breast-feeding did not seem to influence the fatty acid pattern of serum lecithin.

Studies on duration of a late recovery period after chronic abuse of ethanol. A cross-sectional study of biochemical and psychiatric indicators.

A cross-sectional study on patients with different abstinence time was performed to describe long-time biochemical and psychiatric changes due to withdrawal from heavy alcohol abuse. Physical, neurological, psychiatric and biochemical parameters were measured in 70 patients with a withdrawal period ranging from 2-90 days. The various parameters changed over time in different manners. Fatigability, reduced sleep, reduced sexual interest, apparent sadness, hostility and global ratings of abstinence improved significantly with the duration of the recovery period. Symptoms related to brain hyperexcitability such as fatigability, inner tension, insomnia and pains persisted for approximately 5 weeks. Of the biochemical parameters, the transaminases were normal in patients with more than 10 days of abstinence, while the levels of gamma-glutamyltransferase and HDL-cholesterol remained high for longer periods. The essential fatty acid status, measured by the fatty acid composition of serum lecithin, appeared to be normal only in patients with long recovery time. MAO in platelets was significantly lower than in the controls. The highest values were seen in the early recovery phase, which may indicate a temporary increase. Since polyunsaturated fatty acids are important constituents of synaptic membranes and since platelet MAO may reflect brain MAO, we consider these co-existing findings important in the interpretation of the psychiatric symptoms. The study demonstrated the existence of a subacute withdrawal syndrome lasting for 4-6 weeks.

Relative fatty acid composition of serum lecithin in the second half of the normal pregnancy.

Fasting vein blood samples from 21 apparently normal pregnant women were collected in 4-week intervals from the 24th week of gestation until delivery. The relative fatty acid composition of serum lecithin was analyzed by gas-liquid chromatography. Palmitic acid increased successively concomitant with a decrease in stearic acid which indicates that serum lecithin is predominantly synthesized along pathway I. Linoleic acid decreased successively parallel to an increased incorporation of longer polyunsaturated fatty acids and non-essential monoenoic (palmitoleic and oleic) acids. The increased incorporation of longer polyunsaturated fatty acids is suggested to be associated with the increased activity of the deacylation-reacylation cycle. The increase of nonessential monoenoic fatty acids is suggested to be associated with a reduced de novo incorporation of linoleic acid.

Metabolic studies in gestational diabetic women during contraceptive treatment: effects on glucose tolerance and fatty acid composition of serum lipids.

Intravenous glucose tolerance tests (IVGTT) with simultaneous assessment of plasma insulin and analyses of the fatty acid composition of serum lecithin and cholesterol esters were performed in 11 women with previous gestational diabetes before and repeatedly during 6 months' administration of a low-dose progesterone (lynestrenol = LYN). 8 of these women were also followed in an identical manner during 6 months of nonhormonal contraception (intrauterine device = IUD) and additionally 6 of these women were followed also during the use of a combined oral contraceptive (OC) (ethinyl estradiol + lynestrenol - EE + LYN). LYN did not alter the IVGTT or plasma insulin but decreased the proportion of polyunsaturated fatty acids (PUFA) in serum lecithin (p less than 0.01) and cholesterol esters (p less than 0.01) where oleic acid was reciprocally increased (p less than 0.05). After 6 months' use of IUD, on the other hand, the k value of IVGTT increased by 45% (p less than 0.01) without significant changes in plasma insulin. In both lecithin and cholesterol ester PUFA increased (p less than 0.05) and cholesterol ester oleate decreased (p less than 0.01); i.e., virtually the reversal of the changes seen during LYN administration. The combined OC, EE + LYN, caused a decrease in the k value by 27% (p less than 0.05) which was apparent even when compared to the effects of LYN alone. EE + LYN also increased (p less than 0.05) lecithin palmitate and decreased stearate (p less than 0.05) and had a concomitant tendency to lower PUFA and increase oleic acid in both lecithin and cholesterol esters. These results indicate that LYN has little influence on the glucose tolerance in women predisposed to diabetes but may provide poorer conditions for dietary treatment of subclinical diabetes than do nonhormonal IUDs. The combined CO, EE + LYN, on the other hand, promptly diminishes glucose tolerance and may also have an unfavorable influence on liver metabolism.

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.

Treatment with oral estrone sulphate in the female climacteric: I. Influence on lipids

Twenty women in the perimenopause were studied for 12 months during which sodium-piperazine-estrone-sulphate 2.5 mg/day was given for 3 weeks out of 4 as a hormone replacement therapy. Blood samples were drawn at the start of therapy, then after 3, 6 and 12 months and analyzed for serum triglyceride, total cholesterol, cholesterol content of high density lipoprotein (HDL) fraction and the relative fatty acid composition of serum lecithin. Triglyceride levels were increased after 3 months (p less than 0.01). After that there was a gradual decline to almost pretreatment levels. Total cholesterol decreased during the latter period of treatment and became virtually normal; significantly lower levels (p less than 0.01) were found at 12 months. The HDL-cholesterol, which constitutes most of the high density lipoprotein fraction, showed a continuous increase and reached statistical significance at 12 months (p less than 0.01). This type of lipoprotein pattern is associated with a reduced risk of ischemic cardiovascular disease. After 3 and 6 months of treatment an increase in the relative content of palmitic acid in serum lecithin was seen, an increase that might indicate an altered liver lecithin synthesis, usually seen in cholestasis. However, after 12 months the palmitic acid level declined and was not significantly altered from the pretreatment value, indicating that the change was transitory.

Studies in normal pregnancy: III. Fatty acid composition of serum phosphoglycerides and cholesterol esters

Metabolic and hormonal influences on liver lipid synthesis are reflected in the relative fatty acid composition of serum lecithin. Thus, a successive decrease in essential fatty acids (EFA), i.e. n-6 fatty acids, during pregnancy would indicate an incipient EFA deficiency at the time of delivery. Furthermore, reciprocal changes in linoleic and arachidonic acids during the 1st trimester with an increase in arachidonic acid would suggest an enhancement of the Greenbeg Pathway (Pathway II) in lecithin synthesis presumably caused by estrogen influence. During the 2nd and 3rd trimester, reciprocal changes in lecithin content of palmitic and stearic acids are similar to changes appearing under cholestasis. It is furthermore suggested that variations in the utilization of linoleic acid in cholesterol esters (expressed as cholesterol ester 18:2/lecithin 18:2) might reflect changes in plasma cholesterol esterification by the enzyme lecithin-cholesterol-acyl-transferase (LCAT). Then, in late pregnancy, in relation to a subclinical cholestatic liver engagement, LCAT activity would increase as judged from this ratio as well as the increased linoleic acid in cholesterol esters.

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.

LIPID METABOLIC STUDIES IN OOPHORECTOMIZED WOMEN. EFFECTS OF THREE DIFFERENT PROGESTOGENS

Ten oophorectomized women (ranging in age from 27 to 45 years, having a mean age of 34.5 years with a standard deviation of 5.3) were given three different progestogens (norgestrel, norethisterone and medroxyprogesterone) in treatment periods of 3 weeks' duration immediately preceded by 3 weeks "wash out" periods. Venous blood samples were drawn before and after each treatment period. Free and total cholesterol, triglycerides and phospholipids were determined in the three lipoprotein fractions: Very low density lipoproteins (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL). Individual phosphatides were determined after thin layer chromatography. In addition, the relative fatty acid composition of serum lecithin and cholesterol esters were assessed by gas-liquid-chromatography. Both norethisterone and norgestrel caused a decrease in alpha-lipoprotein cholesterol. The relative fatty acid composition of serum lecithin revealed an increase of biochemical pathway 1 for liver lecithin synthesis on norgestrel and norethisterone but no major changes on medroxyprogesterone. With norgestrel an increase in serum-lysolecithin concomitant with a decrease in lecithin was observed, while the two other progestogens did not induce any significant changes. From the present data it is suggested that the 19-norethisterone derivatives, norethisterone and especially norgestrel, have androgen-like influences on lipid metabolism. Medroxyprogesterone, being a 17-alpha-hydroxyprogesterone, caused less changes and consequently less disturbance of lipid metabolism.

Studies in cholestasis of pregnancy. VI. Fatty acid composition of glycero-phospholipids before and after delivery.

Eight pregnant women, complaining of generalized pruritus with lipoprotein-X (LP-X) in their serum and diagnosed as cases of cholestasis of pregnancy (CP)--were studied during pregnancy and after delivery. Ten women with uncomplicated normal pregnancy served as controls. LP-X, liver function tests and relative fatty acid composition of serum lecithin (determined by gas-liquid chromatography, GLC) were followed. The fatty acid composition in liver and serum lecithin is determined by the synthesis pathways of lecithin in the liver. The faster and quantitatively dominating cytidine-diphosphate diglyceride pathway, pathway I, causes the appearance of lecithin with palmitic acid (16:0) in 1-position and oleic (18:1) or linoleic (18:2) acid in 2-position, while pathway II, with methylation of phosphatidyl-ethanolamine (cephalin) preferentially cases the appearance of lecithin with stearic acid (18:0) in 1-position and arachidonic acid (20:4) in 2-position. Pathway I is enchanced by oestrogenic and pathway II by cholestatic influence. During pregnancy women with CP were characterized in their serum lecithin fatty acid composition by a high palmitic (16:0) and a high oleic (18:1) acid content, in agreement with earlier studies. After delivery, in women with prior CP a decrease in palmitic (16:0) and linoleic (18:2) acids and an increase in stearic (18:0) acid, was interpreted as decreased influence on the major lecithin synthesis pathway I and an enhancement of pathway II. In addition, after delivery in the lactating mother, serum lecithin fatty acid composition data revealed an essential fatty acid (EFA) "consumption." It was earlier shown, that women with previous CP (when studied 8--21 months after delivery) had as judged from their serum lecithin fatty acid composition, a "basic metabolic defect," expressing presumably as estrogen enhanced pathway II of liver lecithin synthesis. In the present study, soon after delivery (on day 4--8) women with prior CP showed, however, less pathway II influence than women with a prior normal pregnancy. This was interpreted as a presistence of the cholestatic influence on liver lecithin synthesis pathways at this short time after delivery. Serum lecithin fatty acid composition appears to be a sensitive variable for the evaluation of metabolic influences in the liver.

Serum Lipids and Fatty Acid Composition of Serum Lecithin in the Non‐Pregnant State in Patients with Previous Cholestasis of Pregnancy

Serum lipids and fatty acid composition of serum lecithin were studied 8-21 months after delivery in 20 non-pregnant women who during their latest pregnancy had presented signs of CP. These women were compared with normal non-pregnant women (n=18) and with patients with cholestasis of pregnancy (CP) (n=28). In the non-pregnant state women with previous cholestasis of pregnancy (CP) showed in serum lecithin a low relative content of palmitic (16:0) and linoleic (18:2) acids and a high portion of stearic acid (18:0). These findings indicate as a basic defect in CP, a reduction in liver lecithin synthesis via pathway I (Kennedy's pathway) in favour of an increased pathway II (Greenberg's pathway). These data further support the hypothesis of increased estrogen activity as an etiological factor in CP. The basic influence by pregnancy on serum lipids and serum lecithin fatty acid composition was the same in women with CP as in women with a normal pregnancy.

Studies in cholestasis of pregnancy. V. Gallbladder disease, liver function tests, serum lipids and fatty acid composition of serum lecithin in the non-pregnant state.

Women from an earlier series of cholestasis of pregnancy (CP) were called for a retrospective study to consider presence of gallstones in the gallbladder (evaluated by cholecystography), liver function tests, serum lipids and lipoproteins and the relative fatty acid composition of serum lecithin (as determined by GLC). The attendance in the retrospective study was 60%. Estimated on the total series (assuming that none of the non-responders would have a positive X-ray), the incidence of gallbladder disease was 23.7%. Among women with previous cholestasis of pregnancy and with a positive X-ray finding no characteristic changes in liver function tests or serum lipids were revealed. The women with positive X-ray had, however, a lower alpha-lipoprotein cholesterol than women with negative X-ray. A characteristic finding among women with positive X-ray was furthermore the low relative content of palmitic acid (16:0) in serum lecithin. Also women with negative X-ray had a lower relative content of palmitic acid than controls. It is suggested that the low palmitic acid content is expressive of an influence on liver lecithin synthesis pathways and that the serum lecithin fatty acid composition reflects similar changes in bile lecithin. The "basic defect" in CP influencing liver lecithin synthesis might be the primary cause for disturbed cholesterol solubility in bile and of the frequent occurrence of gallstones in CP.

Studies in normal pregnancy. I. Serum lipids and fatty acid composition of serum phosphoglycerides.

Elevated serum lipids in normal pregnancy have been confirmed by the present study. In normal pregnancy the relative fatty acid composition of serum lecithin was characteristically high in palmitic acid (15:0). From the present knowledge of lipid metabolism in pregnancy there is no obvious explanation for this finding. Furthermore, the serum lecithin relative fatty acid composition mirrored a possible dietary influence with a decrease in the essential fatty acid, linoleic (18:2) and arachidonic (20:4) acids and of the sum of the fatty acid of the linoleic acid series (n-6). This expression for a relative deficiency in essential fatty acids might be due to changes in dietary habits during pregnancy, e.g. an increase in particularly refined carbohydrates. Reciprocal changes in oleic (18:1) and linoleic (18:2) acids further support this suggestion. An expected increase in serum lecithin containing arachidonic acid (20:4)-due to estrogen influence on liver lecithin synthesis-could not be verified in week 34 of the normal pregnancy.

Polyunsaturated fatty acid lipidosis infantile form of so-called neuronal ceroidlipofuscinosis.

ABSTRACT. Hagberg, B., Haltia, M., Sourander, P., Svennerholm, L. and Eeg‐Olofsson, O. (Departments of Paediatrics II, Pathology I and Neurochemistry, University of Gothenburg, Sweden, and Pathology II, University of Helsinki, Finland). Poly‐unsaturated fatty acid lipidosb—an infantile form of so‐called neuronal ceroidlipo‐fuscinosis. Acta Paediatr Scand, 63:753, 1974.—Clinical, histological and ultrastructural findings in three children of Finnish origin and with a severe progressive encephalopathy are reported. The main symptoms were rapid developmental regression from about one year of age, loss of speech, severe visual failure and pronounced secondary microcephaly. A decerebrated state was reached within 1–3 years. Laboratory tests revealed a successively decreasing CSF τ‐fraction. The fatty acid composition of Serum lecithin showed an increased amount of arachidonic acid in the early stage of the disease, a pattern consistent with the biochemical changes in the brain.The morphological characteristics consisted of extreme cerebral and cerebellar atrophy, massive neuronal destruction associated with a pronounced macrophage and astrocytic reaction, and strongly PAS‐reacting and autofluorescent granular deposits in the cytoplasm of the remaining cells. Electron microscopy revealed cytoplasmic osmiophilic deposits in the form of aggregates of globules with a uniform and finely granular ultra‐structure.The condition was considered to be a nosological entity with a uniform clinical picture and characteristic ultrastructural changes in the brain. The evidence produced suggests that the disease described is identical with a progressive heredodegenerative disorder, known to have been diagnosed during recent years in more than 50 Finnish infants and small children and earlier described under the name of infantile type of so‐called neuronal ceroidlipifuscinosis.