Protein-energy malnutrition during gestation and lactation in rats affects growth rate, brain development and essential fatty acid metabolism.

The influence of feeding a low protein diet to rat dams during gestation and lactation on lipid metabolism in pups was studied. Wistar rats were fed 5, 10, 15 and 25% dietary protein during gestation and lactation. Pup growth was monitored until weaning, and brain weight, protein concentration, proteolipid concentration and total lipid phosphorus concentration of brain were analyzed. The levels of fatty acids in dam milk as well as in pup liver phospholipids and brain prosphatidylcholine and phosphatidylethanolamine were determined. The progressive deprivation of maternal dietary protein produced a reduction in the total saturated fatty acid concentration of dam milk and an increment in the concentration of nonmetabolized linoleic acid. Pup body and brain weights as well as proteolipid, protein and total lipid phosphorus concentrations in brain were reduced in proportion to the degree of dietary protein deficiency. The products:precursor ratio of (n-6) fatty acids in liver phospholipids revealed an impairment in the elongation-desaturation pathway due to maternal protein deficiency. Both (n-6) and (n-3) polyunsaturated fatty acids within brain phosphatidylethanolamine were decreased by reduced maternal dietary protein intake, whereas only the linoleic acid-derived products were similarly affected in the corresponding phosphatidylcholine fraction. These results demonstrate the widespread and profound deleterious effects of low protein levels of maternal diet on the growth rate, brain development and fatty acid metabolism in rat pups.

[Effect of the administration of corn oil on the composition of fatty acids of plasma phospholipids in normal and malnourished infants fed with cow's milk]. / Efecto de la administración de aceite de maíz sobre la composición en ácidos grasos de los fosfolípidos del plasma de lactantes normales y desnutridos alimentados con leche de vaca.

The effect of corn oil diet administration on the essential fatty acids (EFAs) profiles was evaluated in plasma phospholipids from normal and malnourished cow's milk fed infants nursing infants. A control group of only breast-fed was also selected for this study. The fatty acid composition was determined by gas-liquid chromatography and used as biochemical variable for evaluating EFA status. A fall in the proportion of fatty acids concomitant with an increase in the saturated fatty acids, consistent with a pattern of essential fatty acid deficiency (EFAD) was observed in the cow's milk fed infants, either normal or malnourished (Table 2). The corn oil administration was capable of restoring the fatty acid profile to normal values, similar to the values of the control group of breast-fed infants, even in malnourished infants, although during the 15 days test they did not correct their clinical syndrome of malnutrition (Table 3). Calculation of the product-precursor of the linoleic acid provided evidence for the positive effect of the corn oil administration.

Efecto de la administración de aceite de maíz sobre la composición en ácidos grasos de los fosfolípidos del plasma de lactantes normales y desnutridos alimentados con leche de vaca. / [Effect of the administration of corn oil on the composition of fatty acids of plasma phospholipids in normal and malnourished infants fed with cows milk]

The effect of corn oil diet administration on the essential fatty acids (EFAs) profiles was evaluated in plasma phospholipids from normal and malnourished cows milk fed infants nursing infants. A control group of only breast-fed was also selected for this study. The fatty acid composition was determined by gas-liquid chromatography and used as biochemical variable for evaluating EFA status. A fall in the proportion of fatty acids concomitant with an increase in the saturated fatty acids, consistent with a pattern of essential fatty acid deficiency (EFAD) was observed in the cows milk fed infants, either normal or malnourished (Table 2). The corn oil administration was capable of restoring the fatty acid profile to normal values, similar to the values of the control group of breast-fed infants, even in malnourished infants, although during the 15 days test they did not correct their clinical syndrome of malnutrition (Table 3). Calculation of the product-precursor of the linoleic acid provided evidence for the positive effect of the corn oil administration.

Metabolic transformation of intracraneally injected [1-14C]linoleic and [1-14C]alpha-linolenic acids in malnourished developing rats.

The effect of a low protein diet during pregnancy and lactation on the fatty acid composition of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from brains of ten-day-old rats was studied. The results indicated that partial deprivation of protein during early development was associated with an increase in the fatty acids of the n-9 family in PC. The fatty acids of the linoleic acid series decreased in PE but were not modified in PC. These minor changes did not affect the double bond index values either in PC or in PE. The effect of protein depletion on the in vivo metabolic transformation of intracraneally injected [1-14C]linoleic and [1-14C]alpha-linolenic acids was also studied. The percentage distribution of the labeled precursors and their derivatives among PC and PE differed from that of mass distribution. These results indicate that the direct uptake of polyunsaturated fatty acids from the blood and/or the low turnover rate of these acids incorporated into PC and PE might be involved in maintaining the fatty acid pattern of these brain lipids.

Effects of an eicosapentaenoic and docosahexaenoic acid concentrate on a human lung carcinoma grown in nude mice.

The effects of the n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on the growth of a human lung mucoepidermoid carcinoma (HLMC) in athymic mice were studied. The mice were divided into three groups which were given either a control chow diet (C), a chow diet supplemented with EPA/DHA (P) (25 or 50 mg of free n-3 fatty acids/g of pellet/day), or chow diet supplemented with palmitic acid (S) (isocaloric with P). Two independent experimental schedules were followed: i) host mice bearing either tumors that were allowed to reach 4000 mm3, or only 35 mm3, were fed C, P or S for 21 or 41 days; ii) animals were fed C, P and S for 9 days before tumor implant and were maintained on these diets throughout tumor growth. Food consumption, mouse weight and liver/body weight ratio showed no significant differences between supplemented diets and chow. Tumor growth was markedly inhibited (45%) in both experiments by the EPA/DHA supplemented diet. In Experiment 2, only 60% of mice fed diet P had tumors. The fatty acid composition of neutral and polar lipids of host liver and tumor reflected the dietary intake of n-3 fatty acids; the content of arachidonic acid was reduced by 50%, and EPA/DHA was increased 3- to 5-fold. Tumor prostaglandin E2 levels were reduced 7.4-fold in the P group. The reduced PGE2 content may be a factor in tumor growth inhibition.

Interrelationship between protein-energy malnutrition and essential fatty acid deficiency in nursing infants.

The influence of severe protein-calorie malnutrition on essential fatty acid (EFA) status was evaluated in nursing infants aged 2-5 mo. A control group of the same age and with normal weight-for-height was also selected for this study. The fatty acid pattern of total phospholipids from plasma and red blood cells (RBCs) was determined and then used as a biochemical variable for evaluating EFA status. A sharp fall in the relative percentage of n-6 (omega-6) fatty acids concomitant with an increase in the n-9 fatty acids in plasma and RBC phospholipids was observed. These results are consistent with the picture of EFA deficiency and showed that the deficiency state is well correlated with the severity of malnutrition. Calculation of the product-precursor ratio of polyunsaturated fatty acids derived from linoleic acid (18:2n-6) in RBC phospholipids provides evidence for an impairment in the elongation-desaturation pathway promoted by the protein-calorie malnutrition.

In vitro effect of eicosapentaenoic and docosahexaenoic acids on prostaglandin E2 synthesis in a human lung carcinoma.

The capacity to synthesize both prostaglandins E1 (PGE1) and E2 (PGE2) has been determined in human lung mucoepidermoid carcinoma homogenates when [14C]-fatty acid precursors were added to the incubation medium. Only 10% of the total radioactivity recovered in PGs was found in PGF1 alpha and PGF2 alpha. The experiments were principally focused to inhibit the PGE2 synthesis either with pure eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids or with mixtures of both n-3 fatty acids obtained from fish oil. The results demonstrated that significant inhibitions were found when using 25 microM or a higher concentration of pure EPA or DHA in the incubation medium; however, 5 microM of mixtures of different EPA/DHA ratio caused the same inhibition. The results suggest that EPA and DHA, when added together, may enforce their inhibitory effect on PGE2 synthesis.

Microsomal fatty acid desaturation and elongation in a human lung carcinoma grown in nude mice.

Since tumor cells show abnormal fatty acid composition, it is likely that their desaturase systems were affected to some extent. Although desaturase activities in experimental tumors have been evaluated, to our knowledge, fatty acid desaturases in human neoplasms and particularly in human tumors grown in nude mice have not been assessed yet. We have therefore, chosen a rapidly growing human lung mucoepidermoid carcinoma (HLMC) grown in nude mice to study microsomal fatty acid desaturation and chain elongation activities. Tumor microsomal proteins were incubated with unlabeled malonyl-CoA and one of the following fatty acids: [1-14C]palmitic (16:0), [1-14C]linoleic (18:2), alpha-[1-14C]linolenic (alpha-18:3), and unlabeled gamma-linolenic (gamma-18:3) plus [2-14C]malonyl-CoA. Data show that HLMC microsomes were capable to desaturate 16:0, alpha-18:3, and dihomogammalinolenic acids (20:3) by delta 9, delta 6 and delta 5 desaturase, respectively; however, delta 6 desaturase activity on [14C]18:2 was not detected. The microsomal elongation system was active in all fatty acid series tested except for 18:2. These findings show that the undetectable activity for 18:2 desaturation is not exclusively found in experimental tumors.

Changes in the plasma free fatty acid composition during VLDL lipolysis induced by heparin: their effect on platelet phosphatidylcholine biosynthesis.

The contribution of the acyl specificity of post heparin lipolytic enzymes to changes in the plasma free fatty acid (FFA) pattern during very low density lipoproteins (VLDL) lipolysis, was studied. The effect of these changes in the 3H-choline incorporation into platelet phosphatidylcholine (PC) during incubation, was also investigated. "In vitro" experiments with post heparin plasma and isolated VLDL showed an increase of 61.1 in the percentage of linoleic acid (C 18:2) concomitant with a decrease of 57.1% in the relative concentration of stearic acid (C 18:0) during VLDL triacylglycerol lipolysis. Similarly, a decrease of 39.2% in the plasma concentration of C 18:0 and an increase of 29.4% in the C 18:2 and 9.6% in the oleic acid (C 18:1) concentration were observed after intravenous injection of low doses of heparin. The plasma FFA compositional changes that occur during "in vitro" VLDL lipolysis accelerate not only the incorporation of labeled choline but also the incorporation of C 18:2 into platelet PC. It is suggested that the above observed changes on platelet response are due to the increase in the C 18:2 concentration during incubation.

Tumor lipids and liver lipid metabolism in the model human lung carcinoma/nude mice.

Tumor lipids were studied in the experimental model Human Lung Carcinoma/nude mice as well as the effect of this human neoplasm on the host liver lipid metabolism. Fatty acid profiles from tumoral lipids revealed the loss of specificity for fatty acid composition in triglycerides. Host liver fatty acid composition and cholesterol metabolism were affected by the implanted human lung tissue. A noticeable increase ratio between saturated/unsaturated fatty acids was observed in host liver fatty acid phospholipids (1.17 +/- 0.17) in comparison to control liver (0.84 +/- 0.04). Cholesterol synthesis was assessed "in vivo" by means of [14C]acetate incorporation. The specific radioactivity of [14C] cholesterol was increased by a factor of about 6 in host liver as compared with control liver. This observation along with the marked decrease in the cholesterol content of host liver and the hypocholesterolemia detected in the host mice led us to suggest an increase in the liver cholesterol catabolism promoted by the presence of the tumor.

Effect of the diabetic environment on the lipid metabolism of Ehrlich ascites cells.

One strain of Ehrlich ascites cells lacking of insulin receptors, was grown into control and diabetic mice and cells harvested from diabetic mice reimplanted into control mice. The fatty acid composition of neutral and polar lipids was analyzed and several parameters calculated. Results showed that it is possible to produce similar changes in the lipid fatty acid unsaturation of Ehrlich cells to those observed in the liver of the diabetic bearing mice. These changes may be reverted by growing these cells into control mice. The diabetic environment also promoted a relative increase in the radioactivity from incorporated in vitro into neutral lipids of Ehrlich cells. This metabolic adjustment, probably due to an induction of the enzyme diglyceride acyltransferase, was completely reverted by transplanting these cells in control mice. The metabolic adaptation of Ehrlich ascites cells to the diabetic environment did not modify their biological behaviour as pointed out by their mean generation time. The evidence presented here, showing relatively normal growth of Ehrlich cells in association with changes in the lipid fatty acid pattern and in lipid metabolism, indicates the adaptation of these cells, lacking of insulin receptors, to the environment provided by the diabetic mice.

Metabolism of gammalinolenic acid by human blood platelet microsomes.

The microsomal fraction was used to test the ability of human platelets to metabolize gammalinolenic acid. The microsomal delta 6 and delta 5 fatty acid desaturase activities were measured and the incorporation of [14C]malonyl CoA into prostaglandins was also determined. The results indicate that human platelets have the capacity to elongate gammalinolenic acid (18:3 n-6) to dihomogammalinolenic acid (20:3 n-6) precursor of PGE1. Labeled PGE1 could be detected when human platelets microsomes were incubated with [14C]malonyl CoA in the presence of gammalinolenic acid. The results also show that human platelet microsomes have little delta 6 or delta 5 desaturase enzyme activity.

Effect of protein depletion on the VLDL triacylglycerol secretion and apoprotein synthesis by the perfused liver from pregnant rats.

The effect of protein depletion in the pregnant rat on the polyunsaturated fatty acid incorporation into very low density lipoproteins (VLDL) has been investigated. The apoprotein pattern of these particles was determined. In in vivo experiments the amounts of serum and liver triacylglycerol were determined. VLDL were isolated and their apo C concentration calculated. In in vitro experiments the radioactivity of [3H]leucine incorporated into VLDL apoproteins was measured. The results show that protein depletion during pregnancy promotes a drastic increase in serum and liver triacylglycerol. The VLDL isolated from these animals show an increase in the triacylglycerol/protein ratio and a decrease in their content of apo C. Meanwhile, a significant reduction in the [3H]leucine incorporation into apo C peptides by the perfused liver of protein depleted rats was detected. On the other hand, protein deprivation did not affect labeled linoleic and arachidonic acid incorporation into triacylglycerol of the newly secreted VLDL. Taking these results together, let us deduce that a defective VLDL is secreted by the liver of the protein depleted pregnant rats. The abnormal composition of these particles may influence its normal metabolism through their effects on lipoprotein lipase and this fact could affect the normal supply of polyunsaturated fatty acids to the fetus.

Effect of cross-fostering rats at birth on the normal supply of essential fatty acids during protein deficiency.

The effect of protein deficiency on the activity of delta 6 desaturase in the mother during lactation was determined in the liver microsomal fraction and the fatty acid composition of milk lipids from the analyzed stomach contents. The activity of delta 6 desaturase was profoundly affected by protein deprivation during pregnancy and only reached the values of controls at about 10 days after parturition. This fact did not affect the fatty acid pattern of milk lipids and no significant differences in the contents of arachidonic acid were detected between the two groups. Nevertheless, protein deficiency apparently affected milk production. The effects of protein deprivation on the supply of polyenoic acids of cross-fostering rats at birth from protein-deficient to protein-sufficient diets and vice versa, and rats maintained during pregnancy and lactation on a low protein or control diet were examined. The fatty acid pattern of liver phospholipids of the four groups under study was determined and used as a biochemical parameter for evaluating polyenoic acid status. Protein deficiency markedly affected the fatty acid pattern of liver phospholipids. A significant decrease of both arachidonic and docosahexaenoic acids was observed. This fatty acid pattern was reversed when protein-deficient animals were placed on the control diet at birth. On the other hand, the fatty acid composition of controls was negatively affected by cross-fostering to a deficient diet. The findings from the present experiment provide evidence that the negative effect of protein malnutrition appears to be promoted at least in part, by the effect of protein depletion on the supply of polyenoic acids for normal development and metabolic adaptations.

In vitro conversion of saturated to monounsaturated fatty acid by Ehrlich ascites cells.

In this paper, evidence is presented on the capacity of Ehrlich ascites cells to synthesize in vitro monounsaturated fatty acids from radioactive palmitate. Localization of the double bond was determined by ozonolysis and subsequent reduction of the ozonides to aldesters followed by gas liquid chromatography. These results proved that Ehrlich ascites cells have a delta 9 desaturase that catalyzes the biosynthesis of palmitoleic acid from palmitic acid and oleic and vaccenic acid via elongation-desaturation and desaturation-elongation, respectively, using palmitic acid as substrate. Furthermore, it is shown that, as in the hepatic cells, delta 9 desaturase enzyme activity of the tumoral cells is associated with the endoplasmic reticulum. The electron transport components involved in the desaturase system, i.e., NADH-cytochrome b5 reductase and NADH-cytochrome c reductase, were also measured. The activities of these enzymes do not appear to be rate-limiting in the desaturase activity of these tumoral cells.

Essential fatty acid deficiency in malnourished children.

Fatty acid patterns of major classes of lipids of serum were measured in forty Argentine children ages 2 to 24 months admitted to the hospital with chronic malnutrition. A normal control group of 48 children from the same population was also examined. Serum lipids were extracted and separated into phospholipids, cholesteryl esters, triglycerides, and free fatty acids. These were converted to methyl esters which were analyzed by gas chromatography. In chronic malnutrition, the fatty acid patterns of phospholipids and cholesteryl esters indicated changes characteristic of essential fatty acid deficiency of moderate degree. The total omega 6 acids were found to be highly significantly diminished from normal, and the ratio of 20:3 omega 9/20:4 omega 6 was highly significantly increased. Decreased proportions of omega 6 metabolites suggested impaired desaturase activity, and elevated ratios of 22:4 omega 6/20:4 omega 6 and 20:2 omega 6/18:2 omega 6 suggested increased chain elongation in chronic malnutrition.

Linoleic acid enrichment of serum phosphatidylcholine in humans by low doses of sodium linoleate.

Fifteen volunteers were treated daily during a week with 250 mg of sodium linoleate supply as suppository. A day before and a day after treatment venous blood samples were drawn, high density lipoproteins (HDL) fractionated and 3-sn phosphatidylcholine isolated by thin-layer chromatography from total serum and HDL and their fatty acid composition analyzed by gas-liquid chromatography. The positional esterification of linoleic acid in the phosphatidylcholine molecule was determined by enzymatic hydrolysis. Increases of linoleic acid of 1.8--136.3% in the serum phosphatidylcholine were observed in 14 out of 15 volunteers and an increment of 6.3--32.2% was also detected in the lipid fraction from HDL. In both fractions about 98% of the linoleic acid is located in the C2 position of the phosphatidylcholine molecule. The results reported in the present paper show that it is possible to promote the enrichment of linoleic acid in the phosphatidylcholine fractions of both serum and HDL from humans subjected to low doses of sodium linoleate supply as suppository.