Manipulation of tissue fatty acid profile by intravenous lipids in dogs

This study was undertaken to determine the effects on the fatty acid (FA) composition of various dog tissues of 4 different lipid emulsions (a 100% long-chain triacylglycerol (LCT) derived from soya bean oil emulsion, a mixed 50% medium-chain triacylglycerol (MCT)/50% LCT emulsion as well as both these emulsions supplemented with 10% fish oil (FO) triacylglycerols), when daily infused over 15 days as a substantial component of total parenteral nutrition. Lipids represented 55% of the non-protein energy. Blood samples as well as biopsies from liver, muscle and adipose tissue were taken 15 days before, and again immediately after TPN. In addition, the spleen was also removed immediately after TPN. Tissue FA composition was analysed by gas liquid chromatography of each lipid component after separation by thin layer chromatography. No differences in either safety or tolerance were detected between the different TPN preparations. In particular, infusion over 2 weeks of fat emulsions containing 10% fish oil was tolerated as well as conventional LCT and MCT/LCT emulsions. Relative linoleate content of tissue triacylglycerol (TG) was markedly increased in animals that received the LCT emulsions (e.g. from 22.6 +/- 2.5% to 32.2 +/- 0.6% in the liver), this effect being markedly reduced with MCT/LCT preparations. n-3FA were slightly incorporated into liver TG (from 0.0 +/- 0.0% to 2.3 +/- 0.7% and 1.2 +/- 0.4% for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) respectively, with LCT + FO), but remained undetectable in extrahepatic tissue TG. Of interest, medium chain FA were found in tissue TG after infusion of the mixed MCT/LCT emulsions. As expected, changes of tissue phospholipid (PL) composition involved only long-chain FA. Infusion of soya bean oil emulsion was associated with an increased content of linoleate in liver PL (from 13.6 +/- 0.4% to 17.7 +/- 0.4%), but not in other tissues. MCT/LCT did not markedly affect PL/FA pattern in any tissue. Supplementation with fish oil was associated with an efficient incorporation of n-3FA into tissue PL, particularly in the liver (from 0.4 +/- 0.1% to 2.5 +/- 0.3% for EPA and from 3.9 +/- 0.8% to 9.1 +/- 0.4% for DHA, with the LCT + FO emulsion).     

Effects of parenteral structured lipid emulsion on modulating the inflammatory response in rats undergoing a total gastrectomy

OBJECTIVES: Structured lipid emulsion improves the nitrogen balance and is rapidly cleared from the blood of moderately catabolic patients. However, the effects of structured lipids on inflammatory reactions during major surgery are not clear. This study investigated the effect of a parenteral structured triacylglycerol emulsion on leukocyte adhesion molecule expression and inflammatory mediator production in rats undergoing a total gastrectomy. METHODS: Normal rats with internal jugular catheters were assigned to three experimental groups and received total parenteral nutrition. At the same time, a total gastrectomy was performed on the experimental groups. The total parenteral nutrition solutions were isonitrogenous and identical in nutrient compositions except for differences in the composition of the fat emulsion. Group 1 received a conventional fat emulsion with long-chain triacylglycerols (LCTs), group 2 received a physical mixture of medium-chain triacylglycerols (MCTs) and LCTs (MCT/LCT), and group 3 received structured lipids composed of MCTs and LCTs (STG). Half of the rats in each respective group were sacrificed 1 d and the other half 3 d after surgery to examine the analytical parameters. RESULTS: Plasma cholesterol and free fatty acid levels in the STG group were lower than those in the other groups after surgery. The STG group had lower leukocyte CD11a/CD18 expressions than the MCT/LCT group 3 d after surgery, and CD11b/CD18 expressions in the STG group were lower than those in the LCT group on postoperative days. The STG group had higher monocyte chemotactic protein-1 and macrophage inflammatory protein-2 levels in peritoneal lavage fluid than did the other two groups. CONCLUSION: These results suggest that, compared with the LCT and MCT/LCT groups, rats administered STG had lower plasma lipid concentrations and leukocyte integrin expressions. In addition, STG administration may cause increased recruiting of neutrophils and monocytes at the site of injury and enhance antipathogenicity in rats undergoing a total gastrectomy.     

Leucine metabolism in preterm infants receiving parenteral nutrition with medium-chain compared with long-chain triacylglycerol emulsions

BACKGROUND: Although medium-chain triacylglycerols (MCTs) may be utilized more efficiently than long-chain triacylglycerols (LCTs), their effect on protein metabolism remains controversial. OBJECTIVE: The aim of the study was to compare the effects of mixed MCT-LCT and pure LCT emulsions on leucine metabolism in preterm infants. DESIGN: Fourteen preterm [gestational age: 30+/-1 wk; birth weight: 1409+/-78 g (x +/- SE)] neonates were randomly assigned to receive, from the first day of life, either a 50:50 MCT-LCT (mixed MCT group; n = 7) or an LCT (LCT group; n = 7) lipid emulsion as part of an isonitrogenous, isoenergetic total parenteral nutrition program. On the fourth day, infants received intravenous feeding providing 3 g lipid, 15 g glucose, and 3 g amino acids kg(-1) x d(-1) and underwent 1) indirect calorimetry and 2) a primed, 2-h infusion of H13CO3Na to assess the recovery of 13C in breath, immediately followed by 3) a 3-h infusion of L-[1-13C]leucine. RESULTS: The respiratory quotient tended to be slightly but not significantly higher in the mixed MCT than in the LCT group (0.96+/-0.06 compared with 0.93+/-0.03). We did not detect a significant difference between the mixed MCT and LCT groups with regard to release of leucine from protein breakdown (B; 309+/-40 compared with 257+/-46 micromol x kg(-1) x h(-1)) and nonoxidative leucine disposal (NOLD; 296+/-36 compared with 285+/-49 micromol x kg(-1) x h(-1)). In contrast, leucine oxidation was greater in the mixed MCT than in the LCT group (113+/-10 compared with 67+/-10 micromol x kg(-1) x h(-1); P = 0.007). Net leucine balance (NOLD - B) was less positive in the mixed MCT than in the LCT group (-14+/-9 compared with 28+/-10 micromol x kg(-1) x h(-1); P = 0.011). CONCLUSION: Mixed MCTs may not be as effective as LCT-containing emulsions in promoting protein accretion in parenterally fed preterm neonates.     

Effects of 2 lipid emulsions (LCT versus MCT/LCT) on the fatty acid composition of plasma phospholipid: a double-blind randomized trial

BACKGROUND: Fatty acids from the diet or from IV fat emulsions are incorporated into the plasma and cell membrane phospholipids and act as substrates in the synthesis of eicosanoids. This study reports the effect of 2 parenteral lipid emulsions in plasma phospholipids fatty acids. METHODS: A total of 83 patients aged 18 to 75 years were randomized to receive long-chain triglycerides (LCT) or 50/50 mix of long- and medium-chain triglyceride emulsion (LCT/MCT). Blood samples were collected at baseline and at weekly intervals for 28 days. Plasma phospholipid fatty acids were measured by gas chromatography. RESULTS: Patients receiving LCT versus MCT/LCT emulsion have an increase in 18:2n6 and a decrease in 20:4n6 and 22:4n6 after 7, 14, and 21 days of treatment with parenteral nutrition. Phospholipid fatty acids at 15 days of treatment with parenteral nutrition with LCT versus MCT/LCT for 18:2n6 were 17.30% versus 22,90% (p < .05), for 20:4n6 10.44% versus 8.38% (p < .05), and for 22:4n6 0.51% versus 0.40% (p < .05). The 20:4n6 percentage inversely correlated with the percentage of 18:2n6 on days 7, 14, and 21: regression coefficients: -7.40 (p < .001), -7.39 (p < .001), and 5.70 (p < .001), respectively. CONCLUSIONS: Parenteral lipid emulsions modify fatty acid profiles in plasma phospholipids. MCT/LCT emulsions produce in phospholipids a fatty-acid profile that is closer to normality than that achieved with LCT emulsions. These changes in phospholipid fatty acids are suggestive of an inhibition of A-5-desaturase in patients who received LCT emulsions.     

Effects of medium-chain triglyceride in parenteral nutrition on rats undergoing gastrectomy

This study was designed to investigate the effects of pre-infusion with total parenteral nutrition (TPN) using medium-chain triglyceride (MCT) versus long-chain triglyceride (LCT) emulsion as fat sources on hepatic lipids, inflammatory mediators and antioxidant capacity in rats undergoing gastrectomy. Rats with internal jugular catheter, were divided into two groups and received TPN. TPN supplied 300 kcal/kg/d with 39% of the energy provided as fat. All TPN solutions were isonitrogenous and identical in nutrient composition except for the fat emulsion, which was composed of MCT/LCT (1 : 1) or LCT. After receiving TPN for 5 days, the rats underwent partial gastrectomy and were sacrificed 24 h after surgery. The results of the study demonstrated that the MCL/LCT group had lower hepatic lipids than did the LCT group. No differences in interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha in peritoneal lavage fluid were observed between the two groups. Erythrocyte glutathione peroxidase activity was significantly higher in the LCT group than the MCT/LCT group, although erythrocyte superoxide dismutase activity did not differ significantly between the two groups. These results suggest that infusion with MCT/LCT before an abdominal operation did not have an effect on modulating the production of inflammatory mediators in the location of the injurious stimulus. However, pre-infusion with MCT/LCT have beneficial effect in improving liver lipid metabolism and reducing oxidative stress in rats with gastrectomy.     

Replacement of long-chain triglyceride with medium-chain triglyceride/long-chain triglyceride lipid emulsion in patients receiving long-term parenteral nutrition: effects on essential fatty acid status and plasma vitamin K1 levels

BACKGROUND: In long-term parenteral nutrition (LTPN) patients, the use of a 50:50 mixture of medium- and long-chain triglyceride emulsion (MCT/LCT) has been suggested to prevent or correct fatty liver infiltration. However, the use of MCT/LCT lipid emulsion results in a 50% reduction of essential fatty acids and vitamin K1 supply and could induce essential fatty acid and vitamin K1 deficiencies. This study evaluated the effect of a long-term infusion of MCT/LCT lipid emulsion on plasma fatty acid (FA) and vitamin K1 levels on LTPN patients. METHODS: In a prospective nonrandomized crossover study, we measured plasma phospholipid FA composition by gas chromatography and vitamin K1 levels by high-performance liquid chromatography in 11 LTPN patients before and after a 4-month replacement of the usual 20% LCT lipid emulsion (20% Lipoven; Fresenius-Kabi France, Sèvres, France) by a 20% MCT/LCT lipid emulsion (Medialipide B; Braun Medical, Boulogne, France). RESULTS: Patient received LTPN for 46 +/- 40 months; IV lipid emulsion was 827 +/- 336 mL/week. MCT/LCT lipid substitution did not change most of the essential plasma fatty acid concentrations and did not induce essential fatty acid deficiency. With both lipid emulsions, the triene/tetraene (20:3n-9/20:4n-6) ratio remained within the normal ranges. However, with MCT/LCT lipid emulsion, 22:4n-6 (LCT: 0.50 +/- 0.12; MCT/LCT: 0.63 +/- 0.11%) and 22:5n-6 (LCT: 0.32 +/- 0.11; MCT/LCT: 0.48 +/- 0.15%) increased significantly (p = .022 and 0.011, respectively). Plasma vitamin K1 levels decreased drastically with MCT/LCT lipid emulsion. CONCLUSIONS: An amount of 2.85 +/- 1.55 g x kg(-1) week(-1) of MCT/LCT lipid emulsion neither induced essential fatty acid deficiency nor improved the fatty acid disturbances usually observed in LTPN patients but did induce a drop in plasma vitamin K1 levels.     

Parenteral infusion of long- and medium-chain triglycerides and reticuloendothelial system function in man

Previous study demonstrated that patients who received total parenteral nutrition (TPN) with standard intermittent infusion of long chain triglyceride (LCT) at 0.13 g kg-1hr-1 over 10 hr for each of three days showed a significant decline in 99Tc-sulfur colloid (TSC) clearance rate by the reticuloendothelial system (RES). The present studies evaluated eight patients who received the same total lipid dose of LCT infused continuously as in a three-in-one admixture, and another nine patients receiving the same amount of fat as a medium chain triglyceride (MCT)/LCT (75%/25%) emulsion intermittently over 10 hr at 0.13 g kg-1hr-1 for three consecutive days. Patients were given continuous total parenteral nutrition (TPN) comprised of protein, 1.5 g kg-1day-1, and dextrose, 4.5 g kg-1day-1. RES function was examined by measuring the clearance rates of intravenously injected TSC while receiving TPN containing only protein and dextrose, and again after three days of fat infusion. Mean (+/- SEM) clearance rate constants before and after continuous LCT infusion were 0.38 +/- 0.09 and 0.41 +/- 0.08 min-1, respectively, while those before and after intermittent MCT/LCT infusion were 0.50 +/- 0.18 and 0.73 +/- 0.24 min-1, respectively. In contrast to intermittent LCT infusion, the administration of continuous LCT or an intermittent MCT/LCT mixture does not impair TSC clearance by the RES. These findings suggest that condensing the daily period of LCT infusion at standard dosage may exceed the rate of metabolic utilization, resulting in increased fat removal and diminished TSC uptake by the RES.(ABSTRACT TRUNCATED AT 250 WORDS)     

Short-term effects of parenteral nutrition of cholestatic infants with lipid emulsions based on medium-chain and long-chain triacylglycerols

OBJECTIVE: Infants with chronic cholestasis may require parenteral nutrition with lipid emulsions to provide energy and essential fatty acids but the optimal strategy is controversial. METHODS: We studied the effects of parenteral lipid emulsions with long-chain triacylglycerols (LCTs) or a mixture of LCTs and medium-chain triacylglycerols (MCTs/LCTs) on serum bilirubin and lipid metabolism in cholestatic infants who received these 20% emulsions in alternating order for 3 d each, together with a glucose and amino acid infusion. RESULTS: Of 11 recruited infants, two dropped out because enteral feeding could be established. In nine infants (2-8 mo of age, mean age 4.2 mo) who completed the study, serum bilirubin decreased from baseline to 6 h after the end of LCT infusion (from 8.5 +/- 2.0 to 7.8 +/- 1.8 mg/dL, mean +/- SEM, P < 0.05) and MCT/LCT infusion (7.9 +/- 6.5 to 7.1 +/- 6.5 mg/dL, P < 0.05). Cholesterol, triacylglycerol, and phospholipid concentrations in plasma and in chylomicrons, very low-density lipoprotein, low-density lipoprotein, and high-density lipoprotein were not changed by either emulsion. Total polyunsaturated fatty acid contents in high-density lipoprotein phospholipids increased during LCT infusion (from 29.8 +/- 0.9 to 35.9 +/- 1.4% wt/wt, P < 0.05) and MCT/LCT infusion (from 30.4 +/- 1.0 to 33.0 +/- 0.7%, P < 0.05). The long-chain polyunsaturated fatty acid docosahexaenoic acid increased only with the LCT infusion. Because docosahexaenoic acid availability during infancy is important for early visual and cognitive development, the use of soybean oil-based lipid emulsions may be preferable for infants with severe progressive cholestasis. CONCLUSION: The MCT/LCT and LCT emulsions showed a good metabolic tolerance in infants with chronic cholestasis but had a differential effect on high-density lipoprotein phospholipid contents of arachidonic and docosahexaenoic acids.     

Clinical and metabolic effects of two lipid emulsions on the parenteral nutrition of septic patients

OBJECTIVE: We compared the metabolic and clinical effects of two lipid emulsions, long-chain triacylglycerols (LCT) and a mixture of medium- and long-chain triacylglycerols (MCT/LCT), in septic patients. METHODS: Both groups received total parenteral nutrition (TPN) with a solution enriched with branched-chain amino acids (BCAA). Seventy-two septic patients received TPN with MCT/LCT (group 1) or LCT (group 2). Before starting TPN (basal) and 10 d after (final), various parameters were evaluated. RESULTS: Twenty-six subjects in each group completed the study. Both groups showed an increase in cholestasis enzymes, with no significant changes in lipid parameters. The rise of retinol-binding protein and the recovery of nitrogen balance were significantly greater in group 1. A multivariate analysis of nutritional markers and catabolic parameters showed a better evolution in group 1 (P = 0.002). The MCT/LCT group exhibited a significant increase of insulin levels. Overall mortality and length of stay in the intensive care unit were not affected by the lipid emulsion. CONCLUSIONS: In septic patients who received TPN with a solution enriched with BCAAs, the use of an emulsion containing MCT provided them with a greater recovery of their nutrition status than the traditional LCT formula, without influencing the outcome.     

Inclusion of 10% fish oil in mixed medium-chain triacylglycerol-long-chain triacylglycerol emulsions increases plasma triacylglycerol clearance and induces rapid eicosapentaenoic acid (20:5n-3) incorporation into blood cell phospholipids

BACKGROUND: Lipolysis of a fish oil (FO) emulsion is much slower than that of a soybean [long-chain triacylglycerol (LCT)] emulsion; in contrast, emulsions containing medium-chain triacylglycerol (MCT) are efficiently hydrolyzed by lipoprotein lipase. OBJECTIVES: We questioned whether incorporating 10% FO in a mixed MCT-LCT emulsion would affect plasma triacylglycerol clearance and provide efficient delivery of n-3 polyunsaturated fatty acids to cells and tissues. DESIGN: This prospective crossover study was conducted in 8 normolipidemic subjects with the use of the hypertriglyceridemic clamp model and compared plasma triacylglycerol clearance of a lipid emulsion (5:4:1) made of 50% MCT, 40% LCT, and 10% FO (wt:wt:wt) to a control (5:5) preparation with 50% MCT and 50% LCT. Subjects were daily infused for 5 h, over 4 consecutive days. Fatty acyl pattern was daily measured in plasma phospholipids as well as in leukocyte and platelet phospholipids. RESULTS: Inclusion of 10% FO in mixed emulsion particles enhanced plasma clearance of infused triacylglycerols (18%; P < 0.0001). The faster elimination of the 5:4:1 emulsion appears related to an enhanced uptake of remnant particles rather than to faster intravascular lipolysis. Each infusion of 5:4:1 raised the eicosapentaenoic acid (C20:5n-3) concentration in blood cell phospholipids to reach a 7-fold enrichment in platelets and a >2-fold enrichment in leukocytes after 4 infusions. In contrast, the docosahexaenoic acid (C22:6n-3) concentration remained unchanged in blood cell phospholipids. CONCLUSIONS: Infusion of a mixed emulsion with MCTs, soy LCTs, and FO is associated with efficient plasma triacylglycerol clearance and results in rapid incorporation of C20:5n-3 but not C22:6n-3 in leukocyte and platelet phospholipids.     

Arterial deepvenous difference of lipoproteins in skeletal muscle of patients in postoperative state: effects of medium chain triglyceride emulsion

The effect of fat infusion with medium chain triglycerides (MCT) and long chain triglycerides (LCT) on serum lipoproteins before and after passage through the skeletal muscle was investigated with the forearm technic in eight patients after abdominal operation. All lipoprotein fractions were enriched with triglycerides and phospholipids from infused artificial fat particles with the consequence of significantly increased ratios of TG/PL and TG/apo B in VLDL, of TG/apo B in LDL and TG/apo A-I in HDL. Uptake and release of lipoprotein components by skeletal muscle are given by arterial-deepvenous differences considering the blood flow rates. The positive arterial-deepvenous difference of VLDL triglycerides after 4-hr infusion is interpreted as cleavage and uptake of infused MCT by the muscle. The release of LDL is more pronounced after the fat infusion than before, suggesting a degradation and enhanced catabolism of artificial fat particles. HDL release may be also a consequence of catabolism of artificial TG/PL-particles. These results indicate an uptake of MCT/LCT emulsion by the skeletal muscle.     

Effects of intravenous supplementation with alpha-tocopherol in patients receiving total parenteral nutrition containing medium- and long-chain triglycerides

OBJECTIVE: To compare the effects of a lipid emulsion containing medium-chain triglycerides (MCT) and supplemented with alpha-tocopherol to a conventional long-chain triglyceride (LCT) emulsion. DESIGN: Randomised double blind study. SETTING: Department of Internal Medicine, Antwerp University Hospital. SUBJECTS AND INTERVENTIONS: Twenty-four patients with an indication for total parenteral nutrition for a minimum of 10 days were randomly assigned to two groups: group E received as lipid source MCT/LCT (50/50) suplemented with 100 mg DL-alpha-tocopherol/day and group C received LCT. Blood samples were analysed at inclusion, after 4-6 and after 9-11 days. RESULTS: In group E, serum alpha-tocopherol doubled from 11.4+/-6.9 at inclusion to 20.9+/-7.9 and to 23.8+/-8.8 microg/ml after 4 and 9 days, respectively, but did not change in group C (P=0.008). Production of thiobarbituric acid-reacting substances (TBARS) after 120 min incubation with copper decreased from 66+/-34 at inclusion to 29+/-25 nmol MDA/mg LDL and VLDL-cholesterol after 4 and to 42+/-17 after 9 days (P=0.022 when compared to group C, which underwent no significant changes). Velocity of production of fluorescent products decreased in group E but not in group C (P=0.026). CONCLUSIONS: Supplementation of TPN containing MCT/LCT with 100 mg DL-alpha-tocopherol/day leads to a doubling in serum alpha-tocopherol and to a decrease in the susceptibility of LDL and VLDL to peroxidation in vitro. SPONSORSHIP: This study was partly financed by B Braun Medical NVSA, Diegem, Belgium.     

Triglycerides in fish oil affect the blood clearance of lipid emulsions containing long- and medium-chain triglycerides in mice

Lipid emulsions containing long-chain triglycerides (LCT) and medium chain triglycerides (MCT) are widely used in parenteral nutrition. Recently, fish oil (FO) triglyceride (TG)-derived emulsions are considered therapeutic because of their many beneficial biological modulatory actions. We investigated in mice whether adding 10% FO to an intravenous lipid emulsion with MCT and LCT (MCT:LCT:FO -50:40:10% by wt) would affect particle blood clearance and tissue targeting in comparison to LCT (100% by wt) and MCT:LCT (50:50% by wt) emulsions. The 3 emulsions were labeled with [3H] cholesteryl oleoyl ether and administered by bolus injection (400 microg TG/mouse) to C57BL/6J mice. Contributions of LDL receptor (LDL-R) and LDL-R-related protein to emulsion catabolism were assessed using LDL-R-deficient mice and preinjection of lactoferrin, and the effects of lipoprotein lipase (LPL) were determined by preinjection of heparin and Triton WR 1339. Although fractional catabolic rates did not differ among the 3 emulsions, blood removal at each time point after injection was greater for MCT:LCT:FO particles due to their higher initial margination volume. Compared with MCT:LCT and LCT emulsions, patterns of tissue uptake of the MCT:LCT:FO emulsions were different, e.g. MCT:LCT:FO emulsion particle uptake was lower in heart, adipose tissue, and muscle, and higher in lung, and the removal of MCT:LCT:FO emulsion particles was less dependent on LPL, LDL-R, and lactoferrin-sensitive pathways. These data suggest that the addition of a low percentage of FO to MCT:LCT emulsions substantially changes their particle clearance and tissue uptake mechanisms.     

MCT/LCT emulsion ameliorate liver fat deposition in insulin-treated diabetic rats receiving total parenteral nutrition

This study was designed to investigate the effects of high energy infusion and insulin treatment on plasma and liver lipids in diabetic rats receiving total parenteral nutrition (TPN). Diabetes was induced in rats by streptozotocin. The diabetic rats were assigned to two TPN groups to receive either long chain triglyceride (LCT) or medium chain triglyceride (MCT)/LCT (1:1) as a fat source. The TPN solutions were isonitrogenous, isocaloric and identical in nutrient composition except for the fat emulsion. All rats received the TPN solution at an energy level of 35|kcal/100|g of body weight. The LCT and MCT/LCT groups were further divided into two subgroups, depending on whether they were treated with insulin. The results demonstrated that, between the MCT/LCT and LCT groups, no differences were observed in body weight and nitrogen retention, as well as the concentrations of plasma glucose, nonesterified fatty acids, beta-hydroxybutyrate, and total cholesterol. Diabetic TPN rats without insulin treatment had weight loss and negative nitrogen balance during the experiment. Diabetic TPN rats treated with insulin, however, demonstrated less weight loss and positive nitrogen retention. Insulin treated groups had significantly higher liver fat content than did those without insulin treatment. Furthermore, liver fat content was significantly higher in the LCT group than in the MCT/LCT group among insulin treated TPN rats. These results suggest that compared with the LCT emulsion, infusion of the MCT/LCT emulsion ameliorated liver fat deposition in insulin-treated diabetic rats receiving TPN.     

Changes of hepatic morphology during parenteral nutrition with lipid emulsions containing LCT or MCT/LCT quantified by ultrasound.

Fatty infiltration of the liver with cholestasis is one of the complications of total parenteral nutrition (TPN). The cause has not yet been determined. It seems probable, however, that these alterations could be prevented when a mixture of medium- and long-chain triglycerides (MCT/LCT) is used as a fat component instead of the application of long-chain emulsions (LCT) alone. To determine whether this could also be demonstrated morphologically in man, 14 patients needing TPN (25 kcal/kg BW x day, carbohydrate 45%, fat 35%, protein 20%) were examined by ultrasound in order to compare liver size and gray-scale value before and after 7 days of TPN. Seven of the patients were randomly administered a MCT/LCT emulsion as their fat intake, the other seven were exclusively given LCT. There were no changes in liver size and gray-scale value in the MCT/LCT-group, whereas both parameters showed a significant rise in the patients with LCT (size: 10.4 +/- 1.4 to 11.5 +/- 1.4 cm; gray-scale value: 9.3 +/- 1.0 to 11.6 +/- 0.7). These data suggest that TPN, administered with a mixture of MCT/LCT emulsions as fat components, could reduce the risk of hepatic dysfunction such as cholestasis and fatty infiltration of the liver.     

Medium chain triglycerides in septic patients on total parenteral nutrition

The object of this study was to compare the metabolic effects of a 10% long chain triglyceride (LCT) emulsion with those produced by a 10% emulsion of medium and long chain triglycerides, MCT/LCT. During 7 days, 20 septic patients received total parenteral nutrition. Daily between 9:00 and 21:00 hours, 0.14 ± 0.01 triglycerides/kg body weight/h was infused. Nine received an LCT emulsion, 11 an MCT/LCT emulsion. Venous blood samples were taken on each of the 7 days at 09:00 and 17:00 hours. No signs of complications attributable to the lipid infusion were observed. The plasma concentrations of phospholipids, triglycerides, free glycerol, non-esterified fatty acids, and sometimes cholesterol, rose during the lipid infusion. Blood ketone body levels did not increase. With both emulsions a day by day acumulation of phospholipids (at09:00 and 17:00 hours) in the plasma was observed. Cholesterol also accumulated but only with the LCT emulsion. The nitrogen balance and urinary excretion of creatinine and of 3-methylhistidine/creatinine ratio was lower with the MCT/LCT emulsion, which suggests less muscular catabolism in patients receiving that emulsion.     

Effects of medium-chain and long-chain triacylglycerols in pediatric surgical patients

Medium-chain triacylglycerols (MCTs) have been shown to provide better nutritional support than long-chain triacylglycerols (LCTs). This study compares the efficacy of MCT combined with LCT with LCT alone in pediatric patients with surgical stress. Two groups of patients (n = 19 in each) received equivalent amounts of glucose (12 g. kg. d) and amino acids (2 g. kg. d), but one group received 10% Lipofundin MCT/LCT and the other received 10% LCT (1.5 g. kg. d) in a randomized study. Total parenteral nutrition (TPN) was given for 14 d. Blood and urine samples were collected before and after TPN administration for determination of various biochemical parameters. Indirect calorimetry was also performed to determine respiratory quotients and fuel utilization. After 14 d of TPN in the MCT/LCT group, there was a significantly higher blood lymphocyte percentage, a decreasing tendency of serum asparate aminotransferase and of total and direct bilirubin (P < 0.05). These changes were not observed in the LCT group. A significantly better nitrogen balance and a higher ketogenesis from day 3 were observed in the MCT/LCT group. The MCT/LCT group showed a more marked increased utilization of fat than the LCT group, whereas carbohydrate oxidation was less in the MCT/LCT group than in the LCT group (P < 0.05). In children after surgery, MCT/LCT is more protein sparing and induces a better immune response when compared with LCT-containing lipid emulsion. A TPN regimen containing MCT/LCT is likely to result in rapid oxidation of fats for energy without compromising the respiratory system.     

Parenteral nutrition providing a restricted amount of linoleic acid in severely burned patients: a randomised double-blind study of an olive oil-based lipid emulsion v. medium/long-chain triacylglycerols

It has been claimed that lipid emulsions with a restricted linoleic acid content can improve the safety of total parenteral nutrition (TPN). The tolerability of TPN and its effects on the metabolism of fatty acids were assessed in this prospective, double-blind, randomised study comparing an olive/soyabean oil long-chain triacylglycerol (LCT) with a medium-chain triacylglycerol (MCT)/LCT; 50:50 (w) based lipid emulsion in two groups (O and M, respectively; eleven per group) of severely burned patients. After resuscitation (48-72 h), patients received TPN providing 147 kJ/kg per d (35 kcal/kg per d) with fat (1.3 g/kg per d) for 6 d Plasma fatty acids, laboratory parameters including liver function tests, and plasma cytokines were assessed before and after TPN. Adverse events encountered during TPN and the clinical outcomes of patients within the subsequent 6 months were recorded. With both lipid emulsions, the conversion of linoleic acid in its higher derivatives (di-homo-gamma-linolenic acid) improved and essential fatty acid deficiency did not appear. Abnormalities of liver function tests occurred more frequently in the M (nine) than in the O (three) group (P = 0.04, Suissa-Shuster test). Seven patients (four from group O and three from group M) died as a consequence of severe sepsis 3-37 d after completion of the 6 d TPN period. When compared with the surviving patients, those who died were older (P = 0.01) and hyperglycaemic at baseline (P < 0.001), and their plasma IL-6 levels continued to increase (P < 0.04). Although fatty acid metabolism and TPN tolerability were similar with both lipid emulsions, the preservation of liver function noted with the use of the olive oil-based lipid emulsions deserves confirmation.     

Lipoprotein metabolism during and after a 6-h infusion ofMCT/LCT vs LCT emulsion in man

We studied, in man, the intravascular metabolism of two lipid emulsions differing in their triglyceride (TG) fatty acid pattern. One emulsion was composed exclusively of soy bean long-chain triglycerides (LCT), the other of a mixture containing a (1:1, wt:wt) ratio of medium-chain triglycerides (MCT) and LCT (MCT/LCT). Both emulsions contained 10% TG and 1.2% of the same egg yolk phospholipid emulsifier. Six healthy volunteers received both emulsions, in random order, at a rate of 0.2 g TG/kg.h for 6 h. An interval of 2 weeks separated the tests. Although the MCT/LCT emulsion provided 39% more TG molecules than the pure LCT emulsion, plasma TG increased to similar levels, indicating a faster elimination of MCT/LCT. The rise of plasma non esterified fatty acids was greater with MCT/LCT (P < 0.001). LDL-TG enrichment was higher with MCT/LCT (P < 0.025) while net transfer of TG to HDL was similar with both emulsions. Cholesteryl ester (CE) enrichment in the 'VLDL' fraction (largely composed of emulsion particles) was markedly less during MCT/LCT than LCT infusions (P < 0.01). CE enrichment of the 'VLDL' fraction persisted up to 6 h after cessation of both lipid infusions. In conclusion, TG from MCT/LCT emulsion appear to be eliminated faster than LCT during an in vivo infusion in man. In accordance with our previous in vitro data, MCT/LCT infusion was associated with a higher transfer of TG to LDL and in a reverse manner, with a lesser acquisition of CE by emulsion particles as compared to LCT infusion.     

含橄榄油脂肪乳剂在食管癌患者术后肠外营养中的应用

目的 研究含橄榄油脂肪乳剂在食管癌术后肠外营养支持中应用的安全性和有效性.方法 60例胸段食管癌根治术患者用SPSS软件产生的随机数字分为对照组(n=30)和研究组(n=30),两组患者术后进行7～10 d的肠外营养支持,采用等氮、等热量、等渗透压、等液体量配方.研究组使用含橄榄油脂肪乳剂,对照组使用中/长链脂肪乳剂.所有患者分别于术前及术后第1天、第8天清晨空腹抽取外周静脉血送检.观测指标:术前营养状态及营养风险评估,包括体重、体重指数、营养风险筛查等;安全性指标,包括血常规、血电解质、谷草转氨酶(AST)、谷丙转氨酶(ALT)、总胆红素、结合胆红素、尿素氮(BUN)、肌酐、血糖等;有效性指标,包括血红蛋白、白蛋白、总蛋白等.结果 两组术后第8天的白蛋白及总蛋白值均在正常范围内,但研究组的测量值较对照组高(P=0.000),且研究组术后第8天与第1天的总蛋白差值较对照组高(P=0.002).术后第8天对照组的AST及BUN值升高,而研究组的AST及BUN均在正常范围且明显低于对照组(P=0.025,P=0.013).两组间在生命体征变化、不良事件发生率、血常规、血电解质、血糖、血脂等方面差异无统计学意义(P均>0.05).结论 含橄榄油脂肪乳剂在食管癌术后肠外营养支持中的应用是安全有效的;相对于中/长链脂肪乳剂而言,其对AST及BUN的影响较小.

Abstract：

Objective To assess the safety and efficacy of an olive oil-based lipid emulsion for parenteral nutrition in patients after esophagectomy.Methods In the randomized controlled trial,60 patients undergoing esophagectomy were divided into study group(n=30,received olive oil-based lipid emulsion)and control group [n=30,received medium-chain triglyceride/long-chain triglyceride(MCT/LCT)emulsion].The parenteral nutrition Was provided for 7-10 postoperative days.The nutritional formulas were equivalent in nitrogen,calorie,osmotic pressure,and fluid volume.Peripheral venous blood tests were performed before operation and on the first and eighth postoperative days.All the patients were evaluated by nutritional status(weight,body mass index,nutritional risk screening,etc.),safety profiles[full blood test,electrolytes,aspartate aminotransferase(AST),alanine amiotransferase(ALT),total bilirubin and direct bilirubin,blood urea nitrogen(BUN),creatinine,blood glucose,etc.],and efficacy indicators(hemoglobin,albumin,total protein,etc.).Results The albumin and total protein levels returned to the normal ranges in beth groups 8 days after operation,although both levels were significantly higher in study group(P=0.000).Also,the difference of total protein levels between the eighth and first postoperative days Was significantly higher in the study group(P=0.002).In addition,the AST and BUN readings returned to normal ranges 8 days after operation in the study group, which were significantly lower than those in control group (P = 0.025, P = 0.013).No serious adverse events were reported in both groups.Other nutritional parameters, renal and hepatic safety profiels, vital signs, and hematology showed no significant difference between two groups.Conclusions Olive oil-based lipid emulsion is a safe and efficient lipid emulsion for parenteral nutrition in patients undergoing esophagectomy.Compared with MCT/LCT, it has less effect on AST and BUN.