Mitochondrial phospholipid composition and microviscosity in myocardial ischaemia.

Normothermic ischaemic arrest of the isolated perfused rat heart causes profound changes in mitochondrial ultrastructure. Since the mitochondrial membranes contain a high percentage of phospholipids, an evaluation of the effect of different periods of ischaemia on mitochondrial phospholipid content and fatty acid composition was made. The results showed that ischaemia had no effect on the content of the different phospholipid classes and no correlation was observed between ultrastructural changes and mitochondrial phospholipid content. However, the phospholipid fatty acid composition of several phospholipids showed marked changes. For example, with lysophosphatidylcholine a progressive increase in the percentage saturated fatty acids was observed with increasing periods of ischaemia, while a reduction occurred in lysophosphatidylethanolamine. To determine whether the ischaemia-induced changes in mitochondrial phospholipid fatty acid composition had an effect on the physical properties of the membrane, the microviscosity of mitochondrial preparations was studied, using the lipophilic probe, 1,6-diphenyl-1,3,5-hexatrine. Mitochondria isolated from ischaemic hearts showed a progressive increase in fluorescence polarization with longer periods of ischaemia, indicating an overall increase in microviscosity. This phenomenon may be responsible for the increased mitochondrial fragility which is characteristic of ischaemic damage.

Effect of a fortified maize-meal porridge on anemia, micronutrient status, and motor development of infants.

BACKGROUND: Maize-meal porridge is used for infant feeding in many African countries, including South Africa. A low-cost, finely milled, maize-meal porridge was fortified with beta-carotene, iron, and zinc (100% of recommended dietary allowance), as well as ascorbic acid, copper, selenium, riboflavin, vitamin B-6, vitamin B-12, and vitamin E. OBJECTIVE: We assessed whether the fortified porridge could reduce anemia and improve the micronutrient status and motor development of infants. DESIGN: Infants aged 6-12 mo (n = 361) were randomly assigned to receive either the fortified or unfortified porridge for 6 mo. Primary outcomes were hemoglobin and serum retinol, zinc, and ferritin concentrations and motor development. Growth was assessed as a secondary outcome. Primary and secondary outcomes were assessed at baseline and 6 mo. RESULTS: Two hundred ninety-two infants completed the study. The fortified-porridge group had an intervention effect of 9.4 microg/L (95% CI: 3.6, 15.1 microg/L) for serum ferritin and 9 g/L (95% CI: 6, 12 g/L) for hemoglobin concentrations. The proportion of infants with anemia decreased from 45% to 17% in the fortified-porridge group, whereas it remained >40% in the control group. The fortified-porridge group achieved on average 15.5 of the 25 motor development score items, whereas the control group achieved 14.4 items (P = 0.007). Serum retinol concentration showed an inconsistent effect, and no intervention effect was observed for serum zinc concentrations. CONCLUSIONS: This low-cost fortified porridge can potentially have a significant effect in reducing anemia and improving iron status and motor development of infants in poor settings. The formulation needs some adjustment in terms of zinc fortification.

Dietary red palm oil improves reperfusion cardiac function in the isolated perfused rat heart of animals fed a high cholesterol diet.

It has been shown that dietary red palm oil (RPO) supplementation improved reperfusion function. However, no exact protective cellular mechanisms have been established. Our aim was to search for a possible cellular mechanism and a role for fatty acids. Rats were fed a standard rat chow, plus cholesterol and/or RPO-supplementation for 6 weeks. Functional recovery, myocardial phospholipid and cAMP/cGMP levels were determined in isolated rat hearts subjected to 25 min of normothermic total global ischaemia. Dietary RPO in the presence of cholesterol improved aortic output (AO) recovery (63.2+/-3.06%, P<0.05) vs. cholesterol only (36.5+/-6.2%). The improved functional recovery in hearts supplemented with RPO vs. control was preceded by an elevation in the cGMP levels early in ischaemia (RPO 132.9+/-36.3% vs. control 42.7+/-24.4%, P<0.05). Concurrently, cAMP levels decreased (RPO -8.3+/-6.9% vs. control 19.9+/-7.7%, P<0.05). Our data suggest that dietary RPO-supplementation improved reperfusion AO through mechanisms that may include activation of the NO-cGMP and inhibition of the cAMP pathway.

Plasma lecithin-cholesterol acyltransferase activity and plasma lipoprotein composition and concentrations in kwashiorkor.

Plasma lecithin-cholesterol acyltransferase (LCAT) activity, lipoprotein composition, and lipoprotein concentrations were measured in 21 children with kwashiorkor before (day 1), during (day 10), and after treatment (day 30). Day 1 LCAT activity (78.2 mumol.L-1.h-1) was decreased with respect to day 10 (139.2 mumol.L-1.h-1, P less than 0.001) and day 30 (108.0 mumol.L-1.h-1, P = 0.08). Plasma total cholesterol (TC), cholesterol ester (CE), and lipoprotein CEs (VLDL, IDL, LDL, and HDL) were reduced relative to days 10 and 30 (P less than 0.001). Before treatment HDL composition was abnormal. On days 1, 10, and 30, the respective mean HDL-apolipoprotein A-I (apo A-I) concentrations were 23.33, 39.66, and 36.08 mumol/L. LDL-apo B concentrations were 0.40, 0.68, and 0.56 mumol/L (P less than 0.01, days 10 and 30 vs day 1). LDL particles on day 1 were decreased in number, depleted of CE, and laden with triacylglycerol and surface lipids. LCAT activity on day 1 correlated with LDL-CE linoleate (P less than 0.05, r = 0.48). Reduced plasma LCAT activity is an important factor related to abnormalities in lipoprotein composition and concentrations.

Serum triglyceride responses to fatty meals: effects of meal fat content.

To determine the dose response of serum triglyceride concentrations to fat feeding, serum triglyceride responses to meals containing 40, 80, and 120 g fat (in the form of dairy cream) were measured in 12 normotriglyceridemic men. Mean postprandial lipemia (measured as the integrated area under the curve of serum triglyceride concentration plotted against time) was 251 +/- 129 mg.dL-1.8 h-1 (2.83 +/- 1.46 mmol.L-1.8 h-1) after the 40-g-fat meal, 503 +/- 233 mg.dL-18 h-1 (5.68 +/- 2.63 mmol.L-1.8 h-1) after the 80-g-fat meal, and 712 +/- 281 mg.dL-1.8 h-1 (8.04 +/- 3.17 mmol.L-1.8 h-1) after the 120-g-fat meal. These data indicate that in normotriglyceridemic men the magnitude of lipemia that follows the ingestion of a fat meal is directly proportional to the fat content of the meal. The results also suggest that the mechanism whereby triglyceride is removed from the intravascular compartment is not saturated by meals containing the amounts of fat typically consumed by men following a Western diet.

Postprandial lipemia and chylomicron clearance in athletes and in sedentary men.

To examine the effects of exercise on postprandial serum triglyceride (TG) metabolism, we measured oral and intravenous fat tolerance and chylomicron-TG half-life in highly trained endurance athletes and in a sedentary control group matched for body weight and fasting serum TG concentration. Postprandial lipemia was lower in athletes after meals containing 40 g fat (1.5 +/- 0.7 vs 2.6 +/- 1.5 mmol.L-1.8 h-1, p less than 0.001) or 140 g fat (2.5 +/- 1.2 vs 6.1 +/- 1.9 mmol.L-1.8 h-1, p less than 0.001). The disappearance of an intravenous bolus of Intralipid was faster in athletes (5.4 +/- 1.2%/min) than in sedentary men (4.3 +/- 0.8%/min, p less than 0.01). The half-life of chylomicron-TG was shorter in athletes (3.0 +/- 0.8 min) than in sedentary men (4.0 +/- 1.0 min, p less than 0.05). These findings indicate that chronic exercise decreases postprandial lipemia by reducing chylomicron-TG's half-life. This effect is due partly to reduced fasting serum TG pool size and partly to a direct effect of exercise on the serum TG removal system.

Plasma lipoprotein response to substituting fish for red meat in the diet.

The effect of 6 wk of either red meat (RM) or fatty fish (FF) intake on plasma lipid concentrations in 28 free-living volunteers (12 males, 16 females) aged 22-45 y was investigated in this clinical crossover trial. Dietary intake was estimated by 7-d dietary records, and fasting blood samples were analyzed for plasma lipid concentrations. Although energy intake did not differ, protein intake was higher (P less than 0.01) in the FF period than in the RM period. There was also a difference (P less than 0.001) in the ratio of dietary polyunsaturated to saturated fatty acids in the RM (0.45) and FF (0.93) periods. Mean plasma total cholesterol, low-density-lipoprotein cholesterol, very-low-density-lipoprotein (VLDL) cholesterol VLDL-triacylglycerol, and plasma triacylglycerol concentrations were lower (P less than 0.001) in the FF than in the RM period. Positive correlations between animal-protein intake and plasma lipoproteins were observed. Atherogenic plasma lipoprotein concentrations were lower when FF was substituted for RM.

Home gardens focusing on the production of yellow and dark-green leafy vegetables increase the serum retinol concentrations of 2-5-y-old children in South Africa.

BACKGROUND: Production of yellow and dark-green leafy vegetables at the household level may provide economically deprived households with direct access to provitamin A-rich foods. OBJECTIVE: The aim of the study was to determine whether the dietary intake of yellow and dark-green leafy vegetables and the serum retinol concentrations of children improve with a home-gardening program. DESIGN: A home-gardening program was integrated with a community-based growth-monitoring system in a rural village. Cross-sectional data were collected at baseline and 20 mo after implementation of the program. The dietary intake, serum retinol concentrations, and growth of 2-5-y-old children and maternal knowledge regarding vitamin A were determined. A neighboring village served as a control village. RESULTS: In the experimental village, 126 home gardens were established, representing approximately one-third of the households. Serum retinol concentrations in the experimental village increased significantly (P = 0.0078), whereas those in the control village decreased significantly (P = 0.0148). At follow-up, children from the experimental village consumed yellow and dark-green leafy vegetables more often and had significantly higher (P = 0.005) serum retinol concentrations (0.81 +/- 0.22 micro mol/L; n = 110) than did children from the control village (0.73 +/- 0.19 micro mol/L; n = 111). Maternal knowledge regarding vitamin A improved significantly in the experimental village (P = 0.001). CONCLUSION: A home-gardening program that was integrated with a primary health care activity, linked to nutrition education, and focused on the production of yellow and dark-green leafy vegetables significantly improved the vitamin A status of 2-5-y-old children in a rural village in South Africa.

Effect of iron-, iodine-, and beta-carotene-fortified biscuits on the micronutrient status of primary school children: a randomized controlled trial.

BACKGROUND: Deficiencies of iron, iodine, and vitamin A are prevalent worldwide and can affect the mental development and learning ability of schoolchildren. OBJECTIVE: The aim of this study was to determine the effect of micronutrient-fortified biscuits on the micronutrient status of primary school children. DESIGN: Micronutrient status was assessed in 115 children aged 6-11 y before and after consumption of biscuits (fortified with iron, iodine, and beta-carotene) for 43 wk over a 12-mo period and was compared with that in a control group (n = 113) who consumed nonfortified biscuits. Cognitive function, growth, and morbidity were assessed as secondary outcomes. RESULTS: There was a significant between-group treatment effect on serum retinol, serum ferritin, serum iron, transferrin saturation, and urinary iodine (P <0.0001) and in hemoglobin and hematocrit (P <0.05). The prevalence of low serum retinol concentrations (<0.70 micromol/L) decreased from 39.1% to 12.2%, of low serum ferritin concentrations (<20 microg/L) from 27.8% to 13.9%, of anemia (hemoglobin <120 g/L) from 29.6% to 15.6%, and of low urinary iodine concentrations (<100 microg/L) from 97.5% to 5.4%. There was a significant between-group treatment effect (P <0.05) in cognitive function with the digit span forward task (short-term memory). Fewer school days were missed in the intervention than in the control group because of respiratory- (P = 0.097) and diarrhea-related (P = 0.013) illnesses. The intervention had no effect on anthropometric status [corrected]. CONCLUSIONS: Fortified biscuits resulted in a significant improvement in the micronutrient status of primary school children from a poor rural community and also appeared to have a favorable effect on morbidity and cognitive function [corrected].

Egg intake does not change plasma lipoprotein and coagulation profiles.

The effect of the intake of 3-14 eggs/wk on biochemical risk markers of coronary heart disease (CHD) was examined in 70 young men who followed a high-fat diet. The study consisted of a run-in phase during which all subjects ate 3 eggs/wk for 2 mo and an experimental phase during which a reference group continued eating 3 eggs/wk and two experimental groups ate either 7 or 14 eggs/wk for 5 mo. The mean coefficients of variation in total plasma cholesterol (5.4-7.4%) were similar in all three groups and were larger than the mean changes of 0.2-5.6% in plasma cholesterol from baseline to end in the experimental groups. Except for increased lecithin-cholesterol acyltransferase activities and total serum protein concentrations, no significant differences in lipoproteins or coagulation factors occurred between groups. It seems that egg intake in this range did not influence CHD risk markers in these subjects. Recommendations to lower risk should probably concentrate on a reduction in fat and not cholesterol intake.

Plasma low density lipoprotein composition in relation to atherosclerosis in nutritionally defined Vervet monkeys.

An atherogenic diet (AD) consisting entirely of normal foods for westernized people was fed to female Vervet monkeys for 4 years. The plasma low density lipoprotein (LDL) cholesterol pool was increased and progression of atherosclerosis was enhanced by the AD compared to a more prudent Western diet. The increased LDL-cholesterol was carried by a 3-fold increase in particles of relatively normal composition and not by packing cholesterol esters into the cores of enlarged LDL particles, as has been reported after feeding semisynthetic diets loaded with extra cholesterol. Nevertheless, these LDL particles were atherogenic. The AD changed the fatty acid composition of LDL-cholesterol esters and triacylglycerol, notably by increasing arachidonic and reducing linoleic acid. Multivariate analysis showed that measures and scores of atherosclerosis were significantly dependent on sphingomyelin and phosphatidylcholine in LDL and on arachidonic acid in LDL-triacylglycerol. Although apolipoprotein B, free cholesterol, esterified cholesterol and lysophosphatidylcholine in plasma LDL and atherosclerosis were significantly positively correlated in bivariate analysis they were not selected by multivariate analysis as the strongest determinants of atherogenesis. Cholesterol in plasma high density lipoprotein was not changed by the AD and lecithin:cholesterol acyltransferase activity in plasma was inversely linked to atherosclerosis. Subcutaneous fatty acids reflected dietary fatty acids.

Low density lipoprotein kinetics in African Green monkeys showing variable cholesterolaemic responses to diets realistic for westernised people.

African Green (vervet) monkeys were fed either an atherogenic Western diet (WD), a prudent diet (PD), or a high carbohydrate diet (HCD) for various lengths of time. Monkeys differed greatly in their response to the WD, and a strong negative correlation was observed between the fractional catabolic rates (FCR) of low density lipoprotein (LDL) and the total plasma cholesterol concentrations (r = -0.83 P = 0.0029). Similarly the individual synthetic rates (SR) of LDL plotted against the total plasma cholesterol concentrations showed a correlation coefficient of r = 0.94 P = 0.01 for WD animals. There was no correlation for PD or HCD animals for either SR or FCR and the total plasma cholesterol concentrations. The aortic lesion scores correlated with the SRs (r = 0.66 P = 0.040) but not with the FCRs. LDL turnover was also studied using 125I-labelled native LDL and methylated 131I-labelled LDL in African Green monkeys showing high or low cholesterolaemic response to an atherogenic Western diet. Measurements after 4 weeks and again after 6 months on the diet showed a decrease in both total and non-receptor mediated clearance of LDL. Receptor-mediated catabolism was significantly lowered in the hyperresponding group (P = 0.0011) and not in the hyporesponding group with a resultant significant difference between the two groups being P = 0.0355 after 6 months. Non-receptor mediated catabolism of LDL was similarly affected in that there was no significant difference between the two groups at 4 weeks but the clearance of methylated LDL was markedly lowered at 6 months, for the hyporesponding group P = 0.0003 and for the hyperresponding group P = 0.0184. Furthermore the hyperresponding group was depressed to a significantly greater extent when compared to the hyporesponding group (P = 0.0241).

The effect of dietary iron deficiency on the fatty acid composition of plasma and erythrocyte membrane phospholipids in the rat.

Severe iron deficiency was introduced in rats by feeding outbred male Wistar rats a purified diet that was either adequate or deficient in iron. The rats were weighed regularly over 4 weeks to monitor body weight differences, after which blood was drawn from a subsample to determine the haemoglobin concentrations and fatty acid composition of plasma total phospholipids and to measure the erythrocyte membrane phosphatidylcholine and phosphatidylethanolamine levels. Comparisons between dietary iron adequate (control) and dietary iron deficient (experimental) rats showed that the experimental rats had lower body weight and plasma total phospholipid linoleic acid levels typical of the symptoms of essential fatty acid deficiency. Erythrocyte membrane phosphatidylethanolamine arachidonic acid levels were increased (P < 0.05) with concomitant decreases in oleic acid (P < 0.01). Correlations between fatty acids and growth suggest that the mechanism whereby iron deficiency affects growth is in some way related to abnormal fatty acid shifts that disturb the delicate balance of essential fatty acids in membranes. Additional omega 3 and omega 6 fatty acids may be necessary to counteract the effect of iron deficiency in rats.

Diet can manipulate the metabolism of EPA and GLA in erythrocyte membrane and plasma.

The effect of diet on the metabolism of eicosapentaenoic acid (EPA) and gammalinolenic acid (GLA) was investigated in two groups of African Green Vervet monkeys fed either a Western atherogenic diet (WAD; %E fat 43.5%; P:S 0.3; n=10) or a high carbohydrate diet (HCD; %E fat 20.5%; P:S 3.4; n=10). Vervets within each dietary treatment were supplemented with 300 mg/day with either an EPA concentrate (50% as free fatty acid, n=5) or a GLA concentrate (70% as free fatty acid, n=5) for 24 weeks, increasing the dose every 6 weeks to a maximum of 2400 mg/kg/day. Vervets in the WAD-Group consumed 433.7 mg/kg/day of EPA and those in the HCD-Group 318.2 mg/kg/day of EPA, whereas 421 mg/kg/day of GLA was consumed in the WAD Group and 340 mg/kg/day in the HCD Group during the last 6 weeks (week 18-24) of the supplementation period. The rate of disappearance of EPA and GLA from plasma and erythrocyte memebrane (EMB) phospholipids were estimated for the two diets after supplementation was stopped. The half-lives (t(1/2)) of EPA in EMB phosphatidylcholine (PC) were estimated to be 34.6 days (WAD) and 22.6 days (HCD), compared to 43.5 days (WAD) and 31.3 days (HCD) in EMB phosphatidylethanolamine (PE). In plasma cholesteryl ester (CE) t(1/2) was 23.5 days (WAD) compared to 14.1 days (HCD), and in plasma triacylglycerol (TAG) 17.4 days (WAD) compared to 9.4 days (HCD). Although accurate estimation of the GLA t(1/2) was difficult to assess due to the low tissue levels (probably due to rapid conversion to DGLA), the disappearance rates of GLA from EMB and plasma also suggested a faster metabolic rate in those animals consuming a HCD compared to a WAD. EPA also disappeared faster from EMB PC than from EMB PE. Disappearance of EPA from plasma TAG was also faster than from plasma CE, probably reflecting their relative turnover and metabolic rates. During supplementation, EPA substituted linoleic acid (C18:2 n-6), arachidonic acid (C20:4 n-6), and GLA (C18:3 n-6). This was reversed when supplementation was stopped. Plasma total cholesterol (TC) levels decreased by 17.06 +/- 17.67% in animals consuming the HCD with EPA as supplement, whereas in those consuming the WAD, plasma TC levels increased with 21.78 +/- 28.23% during the supplementation period. The delay of EPA and GLA disappearance from EMB and plasma in animals consuming a WAD, strongly suggests that metabolism of EPA and GLA is modulated by diet. Such a modulation could cause an accumulation of plasma TC levels that could explain the contradictory results reported by previous studies.

The effect of iron fortification on the fatty acid composition of plasma and erythrocyte membranes in primary school children with and without iron-deficiency.

An intervention study was designed to evaluate the fatty acid (FA) status of children aged 6-11 years before and after iron fortification. Iron deficient (ID) and matched controls without ID (n = 30) were selected. All children received soup (160 mL) fortified with 20 mg iron and 100 mg vitamin C for 15 weeks on school days. Measurements before and after intervention included dietary intake, haematological and iron status and FA composition of plasma and erythrocyte membranes (EMBs). The prevalence of low plasma ferritin concentration and transferrin saturation decreased in the ID children by 40% and 56%, respectively, with intervention. Plasma FAs reflected dietary FA intake. In comparison with controls, the ID group presented with increased percentage total saturated FAs (SFAs; p = 0.0002) in their EMB phosphatidylcholine (PC) and reduced percentage total polyunsaturated FAs (PUFAs; p = 0.0037) before intervention. Lower total n-3 FAs (p = 0.0070) including eicosapentaenoic acid (EPA; p = 0.0034), docosapentaenoic acid (DPA; p = 0.0048) and docosahexaenoic acid (DHA; p = 0.0058) were observed in the ID group. The EMB phosphatidylethanolamine (PEA) of the ID children presented with lower percentages of alpha-linolenic acid (ALA; p = 0.0001), EPA (p = 0.0051) and DHA (p = 0.0084) compared to controls before intervention. Iron intervention was associated with an increase (p < 0,05) in the percentage of n-3 FAs in the EMB-PC and -PEA of the ID group to percentages comparable to that in the control group. It appears that iron status can influence FA metabolism of specific n-3 FAs in the EMBs of young children.

The influence of fish oil supplementation on plasma lipoproteins and arterial lipids in vervet monkeys with established atherosclerosis.

There is controversy about whether supplementing diets with marine fish oil can regress, promote or prevent atherosclerosis. Therefore the effects of an Atlantic pilchard oil (FO) supplement and dietary change were measured in a proven atherosclerosis model. Vervet or African Green monkeys were fed an atherogenic diet (AD) for long enough to ensure progression before treatments started. Matched groups were then treated for 20 months, either by adding FO to the AD (AD/FO), or by changing to a therapeutic diet with FO (TD/FO). Control treatments consisted of supplementing with sunflower oil (SO) instead of FO, so that treatments were AD/SO and TD/SO. The same total polyunsaturates were supplied by the FO and SO and the dose of FO was realistic (2.5% of total energy). A reference group (R) received the TD with no oil supplements. Supplementing with FO did not change the concentrations of total, low or high density lipoprotein cholesterol in plasma. After The AD/FO the intimas of aortas contained more total (p < or = 0.001), free (p < or = 0.05) and esterified (p < or = 0.05) cholesterol, total phospholipid (p < or = 0.01) and sphingomyelin (p < or = 0.05) than after the AD/SO. After FO supplementation eicosapentaenoic acid was significantly higher and arachidonic acid significantly lower in the plasma and aorta intima phosphatidylcholine. None of these changes was anti-atherogenic in terms of atherosclerosis measured in the same individuals (1). Nor did FO increase the efficacy of the TD.

The effect of iron fortification on the fatty acid composition of plasma and erythrocyte membranes in primary school children with and without iron deficiency.

An intervention study was designed to evaluate the fatty acid (FA) status of children aged 6-11 years before and after iron fortification. Iron-deficient (ID) and matched controls without ID (n = 30) were selected. All children received soup (160 ml) fortified with 20 mg iron and 100 mg vitamin C for 15 weeks on school days. Measurements before and after intervention included dietary intake, haematological and iron status and FA composition of plasma and erythrocyte membranes (EMBs). The prevalence of low plasma ferritin concentration and transferrin saturation decreased in the ID children by 40% and 56%, respectively, with intervention. Plasma FAs reflected dietary FA intake. In comparison with controls, the ID group presented with increased percentage total saturated FAs (SFAs; p = 0.0002) in their EMB phosphatidylcholine (PC) and reduced percentage total polyunsaturated FAs (PUFAs; p = 0.0037) before intervention. Lower total n-3 FAs (p = 0.0070), including eicosapentenoic acid (EPA; p = 0.0034), docosapentenoic acid (DPA; p = 0.0048) and docosahexenoic acid (DHA; p = 0.0058), were observed in the ID group. The EMB phosphatidylethanol-amine (PEA) of the ID children presented with lower percentages of alpha-linolenic acid (ALA; p = 0.0001), EPA (p = 0.0051) and DHA (p = 0.0084) compared to controls before intervention. Iron intervention was associated with an increase (p < 0.05) in the percentage of n-3 FAs in the EMB-PC and EMB-PEA of the ID group to percentages comparable to that in the control group. It appears that iron status can influence FA metabolism of specific n-3 FAs in the EMBs of young children.

Effects of a prudent diet containing either lean beef and mutton or fish and skinless chicken on the plasma lipoproteins and fatty acid composition of triacylglycerol and cholesteryl ester of hypercholesterolemic subjects.

In this two-phase crossover study, 39 hypercholesterolemic subjects followed a prudent diet with either lean red meat or fish and skinless chicken (treatment groups), and 13 subjects (reference group) followed their habitual diet. Fasting blood samples were analyzed for plasma total cholesterol, triacylglycerol (TAG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein one- and two-cholesterol, apolipoprotein-B, very low density lipoprotein cholesterol, and very low density lipoprotein TAG, and fatty acid composition of plasma TAG and cholesteryl ester (CE). Body mass and blood pressure were determined. Seven-day dietary records were kept once at baseline and twice during the treatment periods. Significant differences were observed in dietary intake between the baseline and treatment diets and between the two treatment diets. HDL-C (P < 0.05) and diastolic blood pressure (P < 0.01) were higher in patients on the red meat diet than in those on the chicken-fish diet. No other significant differences in lipoproteins were observed between the effects of the two treatment diets. The linoleic acid (%), eicosapentaenoic acid (%), and the eicosapentaenoic acid/arachidonic acid ratios in TAG and CE were higher (P < 0.01) in subjects on the chicken-fish diet than in those on the red meat diet. In conclusion, this study showed that the effect of two lipid-lowering diets containing either lean red meat or skinless chicken and fish on the atherogenic lipoproteins did not differ significantly. A prudent diet with skinless chicken and fish, however, had a more favorable effect on the fatty acid composition of the plasma TAG and the CE than did the lean red meat diet.

An improved rapid thin-layer chromatographic-gas-liquid chromatographic procedure for the determination of free fatty acids in plasma.

Free fatty acids contained in Dole extracts were separated from other lipid components by either a thin layer chromatographic procedure or by a solvent partitioning system. Subsequent gas-liquid chromatographic analysis of methyl esters prepared from fatty acids purified by these two procedures, showed that when fatty acid standards were subjected to these two procedures, comparable recoveries of fatty acids were obtained. When, however, phospholipids and neutral lipids were present in the extracts, the solvent partitioning system yielded 10 to 46% higher values than recorded with the thin layer chromatographic procedure. Compositional data indicated that the higher values measured by the solvent partitioning procedure were probably derived from hydrolysis of other lipid components during the sodium hydroxide step. Purification of fatty acids by the described thin layer chromatographic procedure eliminates this problem and rapidly yields accurate and reliable results.

Free cholesterol concentrations in the high-density lipoprotein subfraction-3 as a risk indicator in patients with angiographically documented coronary artery disease.

BACKGROUND: The pathophysiology of plasma lipoprotein metabolism has long been linked to coronary artery disease (CAD). The present study evaluated the association between plasma lipoprotein lipid and apolipoprotein (apo) components and CAD in a group of 80 consecutive Caucasian patients undergoing coronary angiography. METHODS: Coronary cineangiography was carried out using the Judkins technique and the lesions quantified by calculating a coronary artery lesion score (CALS). Very low- and low-density lipoproteins (VLDL and LDL) were separated by ultracentrifugation, and high-density lipoprotein (HDL) and HDL subfraction-3 (HDL3) isolated by a differential precipitation procedure. Apo A-I, A-II, and B were assayed by endpoint laser nephelometry using specific antibodies. Total cholesterol, free cholesterol, and fatty acid concentrations were measured by gas-liquid chromatography, and lecithin: cholesterol acyltransferase (LCAT) activity by the decrease in the concentration of free cholesterol. RESULTS: On the basis of the presence of CAD, the 80 patients were divided into two groups: 52 (65%) with CAD (mean CALS = 7.8) and 28 (35%) without CAD (zero CALS). The lipoprotein fraction that most clearly differentiated the groups was HDL cholesterol concentration, with a mean +/- SEM value of 36.5 +/- 1.5 mg/dl for those with CAD and 45.1 +/- 2.1 mg/dl for those without (P < 0.01). The mean HDL3 cholesterol concentration was 29.9 +/- 1.2 mg/dl for patients with CAD and 37.4 +/- 1.8 mg/dl for those without (P < 0.001). These differences in HDL cholesterol and HDL3 cholesterol were mainly caused by differences in the free cholesterol component, with a mean HDL free cholesterol level of 10.8 +/- 1.1 and 16.1 +/- 1.4 mg/dl (P < 0.01), and a mean HDL3 free cholesterol level of 7.6 +/- 0.6 and 11.9 +/- 0.8 mg/dl (P < 0.001) in patients with and without CAD, respectively. Plasma LCAT activity was decreased in patients with CAD (P < 0.05), as were the apo A-I and A-II concentrations in both the HDL (P < 0.001) and HDL3 (P < 0.001) fractions. No significant association was found between CAD and HDL2 cholesterol or plasma total cholesterol, LDL cholesterol, or VLDL cholesterol concentrations. A stepwise discriminant analysis revealed that HDL3 free cholesterol was the only variable selected. Using HDL3 free cholesterol as a screening variable for CAD (cutoff 10.55 mg/dl), the sensitivity for CAD was 87% and the specificity for non-CAD 67%. The positive and negative predictive values of HDL3 free cholesterol were 82 and 75%, respectively. CONCLUSION: We have shown that the concentrations of HDL cholesterol and HDL3 most clearly differentiated between patients with and without CAD.