Gallbladder contraction after hormonal manipulations in normal subjects and patients under total parenteral nutrition.

Total parenteral nutrition (TPN) induces biliary dilatation, sludge and formation of gallstones. Cholecystokinin (CCK) induces gallbladder (GB) contraction. During thyrotropin-releasing hormone (TRH) testing for thyroid function, we observed that patients felt a strong micturition reflex attributable to smooth muscle contraction of the bladder. The possibility of GB contraction after TRH administration was studied compared to cholecystokinin-octapeptide (CCK-OP) and/or fatty meal administration. The effect of intravenous (IV) CCK-OP, TRH and a combination of the two on GB volume was studied in normal volunteers without GB or liver disease and in patients receiving TPN for greater than 2 weeks. Subjects included six normal volunteers who received an oral fatty meal only, 18 other normal volunteers (Group A) and 18 TPN patients (Group B). Gallbladder contraction was estimated by ultrasound prior to and after administration of the fatty meal; in the other 36 subjects, GB contraction was calculated prior to and after administration of CCK-OP, TRH, or both. Results are expressed as a percentage of the GB basal volume using each subject as his or her own control. Group A and Group B were each divided into three equal subgroups receiving IV CCK-OP (A1, B1), TRH (A2, B2), or both (A3, B3).(ABSTRACT TRUNCATED AT 250 WORDS)     

Differences in cholecystokinin release and gallbladder contraction between emulsified and nonemulsified long-chain triglycerides.

BACKGROUND: Fat is a potent stimulus of cholecystokinin (CCK) release. Apart from lipolysis, fatty acid chain length, and saturation, emulsification may also determine the magnitude of CCK release. METHODS: We have studied the effect of emulsification of soybean oil on CCK and pancreatic polypeptide (PP) release (radioimmunoassay [RIA]) and gallbladder motility (ultrasonography). Six healthy subjects were studied on three separate occasions in random order during (1) intraduodenal administration of emulsified long-chain triglycerides (LCT) (6 mmol/h for 120 minutes); (2) equimolar amounts of nonemulsified LCT with addition of emulsifier; and (3) saline with emulsifier (control). RESULTS: Intraduodenal administration of both nonemulsified LCT and emulsified LCT induced significant (p < .05) increases in plasma CCK and PP levels and reductions in gallbladder volume. However, compared with nonemulsified LCT, emulsified LCT resulted in a readier and significantly stronger CCK release (212+/-62 pmol/L per 120 minutes vs 36+/-7 pmol/L per 120 minutes; p < .05); PP release (2034+/-461 pmol/L per 120 minutes vs 671+/-106 pmol/L per 120 minutes; p < .05); and gallbladder contraction (77%+/-2% vs 41%+/-7%; p < .05). No significant alterations were observed in plasma CCK or PP levels and gallbladder volume during administration of saline with emulsifier. CONCLUSIONS: Intraduodenal administration of a low-dose emulsified LCT more potently stimulates CCK and PP release and gallbladder contraction in comparison to equimolar amounts of nonemulsified LCT. These findings point to an important role for solubilization of LCT in determining the magnitude of CCK release from the intestine.     

Effect of intravenous fat on cholecystokinin secretion and gallbladder motility in man.

During total parenteral nutrition (TPN) gallbladder bile stasis and hypomotility have been well documented. Little is known, however, about the effect of the separate components of TPN on gallbladder motor function. Inasmuch as fat, administered intraduodenally, is a potent stimulus of cholecystokinin (CCK) secretion and gallbladder contraction we have investigated whether intravenous (IV) fat affects gallbladder motility. Six healthy volunteers were studied on two separate occasions, during infusion of Intralipid 10%, 200 mL/h or saline infusion (control) for 3 hours, to evaluate the effect of IV infusion of fat on (1) plasma CCK concentration and gallbladder volume and (2) CCK-induced gallbladder emptying. Intravenous infusion of Intralipid resulted in significant increases in serum triglycerides from 0.9 +/- 0.1 to 5.1 +/- 1.3 mmol/L (at 90 min). During fat infusion no significant changes in plasma CCK and gallbladder volume were noted when compared with basal values or to the control experiment. During IV fat, concomitant infusion of 0.25, 0.5, and 1.0 Ivy dog unit (IDU) per kilogram per hour of CCK-33 resulted in a significant reduction in gallbladder volume from 26 +/- 6 cm3 (basal) to 15 +/- 4 cm3 (p less than .05), 6 +/- 2 cm3 (p less than .05) and 2.5 +/- 1 cm3 (p less than .05), respectively. No significant differences in CCK-induced gallbladder emptying were observed between IV fat and saline infusion (control). It is concluded that, in contrast to intraduodenal fat, IV infusion of fat does not affect (1) basal plasma CCK and gallbladder volume and (2) CCK-induced gallbladder contraction.     

The influence of dietary medium and long chain triglycerides on growth performances and fat deposition in growing rats.

The present study was undertaken to investigate the effects of dietary medium and long chain triglycerides (MCT and LCT) on fat deposition and fatty acid composition of adipose tissues of rats. Twenty-seven Wistar strain male rats were divided into three groups and fed semisynthetic experimental diets: Basal (AIN 76), MCT (basal+C8:0 10%), LCT (basal+corn oil 10%). Feed intake was measured every day and body weight was measured once a week. At the beginning, 4th and 8th week of experimental feeding, 3, 12, 12 rats were slaughtered, respectively. Liver, perirenal and epididymal adipose tissue pads were weighted and their fatty acid composition was determined. Chemical composition of wholebody carcass was measured. Body weight gain was greater in rats fed the LCT diet than in rats fed the basal and MCT diets. Feed intakes were decreased in rats fed the MCT and LCT diets compared to that of the basal group. Subsequently, when compared to the basal group rats, feed efficiencies in rats fed the MCT and LCT diets were improved at the level of 6 and 14% for 4 weeks, and then 17 and 24% for 8 weeks, respectively. The weight of perirenal and epididymal adipose tissue pads tended to be larger in rats fed the MCT and LCT diets than in the basal group, although not significant. There were not significant differences in wholebody composition among the three groups. But it appeared that in rats fed the MCT diet, moisture content tended to be decreased and crude protein content increased compared to the LCT group rats. Fatty acid composition of the rats fed the LCT diet showed a good reflection of dietary fatty acid composition. Unlike LCT, little of medium chain fatty acid (MCFA) itself were incorporated into liver or adipose tissues. However, it seems that fat deposition of the MCT group was accomplished not by incorporation of dietary fatty acids but by de novo fatty acids synthesis.     

Thermic effect of medium-chain and long-chain triglycerides in man

The thermic effects of 400 kcal meals of medium-chain triglycerides (MCT) and long-chain triglycerides (LCT) were compared in seven healthy men. Metabolic rate was measured before the meals and for 6 h after the meals by indirect calorimetry. Mean postprandial oxygen consumption was 12% higher than basal oxygen consumption after the MCT meal but was only 4% higher than the basal oxygen consumption after the LCT meal. There was a 25-fold increase in plasma beta-hydroxybutyrate concentration and a slight increase in serum insulin concentration after MCT ingestion but not after LCT ingestion. Plasma triglyceride concentrations increased 68% after the LCT meal and did not change after the MCT meal. These data raise the possibility that long-term substitution of MCT for LCT would produce weight loss if energy intake remained constant.     

Comparison between dodecanedioic acid and long-chain triglycerides as an energy source in liquid formula diets

BACKGROUND: Dicarboxylic acids (DA) are water-soluble substances with high-energy density proposed as an alternative lipid substrate for nutrition purposes. The aim of the present study was to investigate the interaction between glucose and DA or long-chain triglyceride (LCT) metabolism after oral administration. METHODS: Two test meals containing either dodecanedioic acid (C12, the 12-atom DA) or LCT, together with glucose and amino acids, were each administered to five healthy volunteers. Tracer amounts of 14C-dodecanedioic acid were added to the C12 meal to recover expired traced CO2 and estimate the minimum rate of C12 oxidation. Glucose, insulin, and C12 plasma levels were measured for 360 minutes after the test meal. Indirect calorimetry was performed for the duration of the study. RESULTS: LCTs proved ineffective in promoting their own oxidation after oral administration. On the contrary, C12 was promptly oxidized, a minimum of 21.9%+/-8.3% of the administered amount giving rise to the recovered expired CO2. This difference in metabolic fate was reflected in a sparing effect on glucose: suprabasal respiratory quotient and suprabasal carbohydrate oxidation were significantly (p < .05) lower under C12 administration than under LCT administration, with a difference of 0.024+/-0.015 in respiratory quotient (RQ) and a difference of 0.791+/-0.197 kJ/min in carbohydrate oxidation. In particular, carbohydrate oxidation increased by 54% over basal with LCT but only by 28% with C12 administration. RQ increased over basal by 5.8% with LCT but only by 3.0% with C12 administration. CONCLUSIONS: These results show a fundamental metabolic difference between conventional lipids and DAs, which is the basis for a possible role of DAs in clinical nutrition. The fate of spared glucose is likely to be storage in glycogen form when dodecanedioic acid is made available as an energy source.     

结构脂肪乳剂在肝硬化病人中的产热及代谢作用

目的：通过比较结构脂肪乳剂与长链脂肪乳剂在肝硬化病人的产热及代谢效应，以评估结构脂肪乳剂在肝硬化病保的应用价值。方法：选择１６例经病理证实为肝硬化病人作为研究对象，进行随机交叉研究。第一组７例病人分别连续输注２０％Ｉｎｔｒａｌｉｐｉｄ或２０％Ｓｔｒｕｅｔｏｌｉｐｉｄ４ｈ（０．２５ｇＴＧ／ｋｇ．ｈ＾－１）第二组９例病人分别连续输注上术脂肪乳剂和葡萄糖混合液６ｈ（０．１７ｇＴＧ／ｋｇ．ｈ＾－１及０．１     

Medium-chain fatty acids: evidence for incorporation into chylomicron triglycerides in humans

The purpose of this study was to evaluate the fatty acid composition of chylomicron triglycerides isolated from subjects fed liquid-formula diets containing 40% of total energy as medium- (C8:0 and C10:0) or long-chain (C16-C18) triglycerides (MCT, LCT) for 6 d. Medium-chain fatty acids (MCFA) comprised 8% of total chylomicron triglyceride fatty acids after the first MCT meal. After 6 d of continued MCT feeding, chylomicron triglyceride MCFA content increased to 13%. When subjects were fed the LCT (soybean oil) diet, C16:0, C18:1, and C18:2 comprised nearly 90% of the chylomicron triglyceride fatty acids. The mass of triglyceride transported in chylomicrons isolated from subjects fed the MCT diet was approximately 20% of that found when subjects consumed the LCT diet. We conclude that although total triglyceride production during MCT ingestion is low, the chylomicron triglycerides that are synthesized contain significant amounts of MCFA.     

Energy expenditure in rats maintained with intravenous or intragastric infusion of total parenteral nutrition solutions containing medium- or long-chain triglyceride emulsions.

Energy expenditure was determined in male Fischer 344 rats (235-246 g) fed by intravenous (IV) or intragastric (IG) infusion with total parenteral nutrition solutions providing 65% of nonprotein energy as fat from long-chain triglyceride (LCT) or a 3:1 admixture of medium-chain triglyceride (MCT) and LCT emulsions. Respiratory gas exchange and somatomotor activity were assessed continuously for 24 h during d 5 and 11 of infusion feeding. The MCT infusion resulted in one-third the weight gain noted with LCT infusion (MCT, 10 +/- 2 g/14 d; LCT, 32 +/- 4 g/14 d; P less than 0.0001). Insulin concentration was 60% higher with IV than with IG infusion and approximately 100% higher with IV-MCT than with IG-MCT or LCT infusion (P less than 0.05). Rats receiving IV infusion of MCT displayed similar levels of motor activity but 8-13% greater daily energy expenditure (kJ.kg-0.75.kJ intake-1) than rats receiving IG-MCT or LCT infusion (P less than 0.05). The MCT infusion also resulted in an elevation in respiratory quotient after cessation of nutrient infusion (MCT, 0.87-0.92; LCT, 0.83-0.85; P less than 0.05). Total and resting energy expenditure decreased approximately 13% from 5 to 11 d of infusion feeding. The lower weight gain and greater energy expenditure seen with MCT- compared with LCT-supplemented total parenteral nutrition may be mediated by higher insulin concentrations.     

Effects of medium-chain triglycerides, long-chain triglycerides, or 2-monododecanoin on fatty acid composition in the portal vein, intestinal lymph, and systemic circulation in rats.

BACKGROUND: Fatty acid absorption patterns can have a major impact on the fatty acid composition in the portal, intestinal lymph, and systemic circulation. This study sought to determine the effects of long-chain triglycerides (LCT), medium-chain triglycerides (MCT), and 2-monododecanoin (2mono) on intestinal fatty acid composition during continuous feeding over a brief period. METHODS: The lipid sources were 100% LCT, 100% MCT, a 50:50 mixture of LCT and MCT (LCT/MCT), and a 50:50 mixture of LCT and 2mono (LCT/2mono). A total of 27 rats were randomly given 1 of the 4 diets at 200 kcal/kg/d, with 30% of total calories from lipids over 3 hours. RESULTS: MCT significantly increased each of the medium-chain fatty acids (C6:0, C8:0, and C10:0) as free fatty acids in the portal vein and about 10%/mol of C10:0 as triglycerides in the lymph compared with the other groups. There was significantly less C10:0 in lymphatic triglycerides with LCT/MCT than with MCT, but more than in the LCT and LCT/2mono diets. MCT also significantly increased the contents of C16:0, C18:0, C18:1, and C20:4 in the lymphatic triglycerides compared with all other groups including LCT/MCT. The amount of linoleic acid (C18:2) in lymphatic triglycerides followed the relative amounts of this fatty acid in the diet, with the greatest in LCT followed by LCT/MCT and LCT/2mono and least in MCT. A so-called structured lipid composed of the medium-chain fatty acid dodecanoic acid on the 2 position and long-chain fatty acids on the 1 and 3 positions appeared to be endogenously synthesized in response to the LCT/2mono diet. CONCLUSIONS: The original differences in MCT and LCT content in the diets were preserved in the fatty acid composition in the intestinal free fatty acids and triglycerides during feeding. In addition, the duration of lipid administration can play a role in altering fatty acid composition in the intestine.     

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.     

Nitrogen sparing effect of structured triglycerides containing both medium-and long-chain fatty acids in critically ill patients; a double blind randomized controlled trial

BACKGROUND AND AIMS: Patients with sepsis and trauma are characterised by hypermetabolism, insulin resistance and protein catabolism. Fat emulsions containing medium chain triglycerides have been suggested to be beneficial for these patients since medium chain fatty acids are a more readily available source of energy when compared to long chain fatty acids. The aim of this study was to compare a medium and long chain triglyceride emulsion consisting of structured triglycerides (ST) with a long chain triglyceride (LCT) emulsion in terms of effects on nitrogen balance, energy metabolism and safety. METHODS: 30 ICU patients with sepsis or multiple injury received a fat emulsion with ST or 20% LCT (1.5 g triglycerides/kg body weight/day) as a component of total parenteral nutrition (TPN), for 5 days in a double blind randomised parallel group design. The main analysis was made on the 3 day per protocol population due to lack of patients at day 5. RESULTS: There were no differences in baseline characteristics of the two groups receiving either the LCT or the ST emulsion. The efficacy analysis was performed on the per protocol population (n=9 ST, n=11 LCT). There was a significant difference between the two treatments regarding daily nitrogen balances when the first 3 days were analysed P=0.0038). This resulted in an amelioration of the nitrogen balance on day 3 in the group on ST as compared to those on LCT (0.1+/-2.4 g vs -9.9+/-2.1 g P=0.01). The 3 day cumulative nitrogen balance was significantly better in the group receiving ST compared to those on LCT (-0.7+/-6.0 vs -16.7+/-3.9 P=0.03). This better cumulative nitrogen balance on day 3 was also preserved as a tendency (P=0.061) in the analysis of the intention to treat population, but on day 5 there was no significant difference (P=0.08). The ST emulsion was well tolerated and no difference was found compared to the LCT emulsion regarding respiratory quotient, energy expenditure, glucose or triglyceride levels during infusion. CONCLUSION: Administration of a structured triglyceride emulsion resulted in an amelioration of nitrogen balance despite no effect on energy expenditure in short term administration over 3 days to ICU patients when compared to a long chain triglyceride emulsion. No side effects linked to medium chain triglycerides were noted.     

Anti-inflammatory effects of long-chain n-3 PUFA in rhinovirus-infected cultured airway epithelial cells

Long-chain n-3 PUFA (LCn-3PUFA) including DHA and EPA, are known to decrease inflammation by inhibiting arachidonic acid (AA) metabolism to eicosanoids, decreasing the production of pro-inflammatory cytokines and reducing immune cell function. The aim of this study was to determine if EPA and DHA reduced the release of inflammatory mediators from airway epithelial cells infected with rhinovirus (RV). Airway epithelial cells (Calu-3) were incubated with EPA, DHA and AA for 24 h, followed by rhinovirus infection for 48 h. IL-6, IL-8 and interferon-gamma-induced protein-10 (IP-10) released by cells were measured using ELISA. Viral replication was measured by serial titration assays. The fatty acid content of cells was analysed using GC. Cellular viability was determined by visual inspection of cells and lactate dehydrogenase release. DHA (400 microm) resulted in a significant 16% reduction in IL-6 release after RV-43 infection, 29% reduction in IL-6 release after RV-1B infection, 28% reduction in IP-10 release after RV-43 infection and 23 % reduction in IP-10 release after RV-1B infection. Cellular DHA content negatively correlated with IL-6 and IP-10 release. None of the fatty acids significantly modified rhinovirus replication. DHA supplementation resulted in increased cellular content of DHA at the cost of AA, which may explain the decreased inflammatory response of cells. EPA and AA did not change the release of inflammatory biomarkers significantly. It is concluded that DHA has a potential role in suppressing RV-induced airway inflammation.     

Parenteral nutrition using MCT/LCT or LCT: Effect on the fatty acid composition of plasma triglycerides and platelet phospholipids

Plasma triglyceride fatty acids and platelet phospholipid fatty acids were compared in 20 malnourished patients before and after 8-10 days of total parenteral nutrition which included either a conventional lipid emulsion (LCT) or a new emulsion containing medium chain triglyercides (MCT/LCT). The use of both lipid emulsions altered the fatty acid profiles. The percentage of linoleic acid in the plasma triglycerides increased with both lipid emulsions, but more markedly with LCT. The median percentage after LCT was 25.9 (range 16.9-31.5) which was significantly higher (p < 0.01) than after MCT/LCT - 14.8 (range 6.1-20.2), or in healthy volunteers. After 8-10 days on MCT/LCT the fatty acid profile retained some features of the malnourished state, despite correction of the linoleic acid content. The percentage of linolenic and arachidonic acid in the platelet phospholipids tended to be lower than after LCT use, and the percentage of linoleic acid was significantly less (p < 0.01), the median (range) being 8.2 (4.5-23.8) after MCT/LCT and 11.7 (4.8-16.0) on LCT. Short term use of MCT/LCT emulsion may correct the fatty acid changes of malnutrition rather more slowly and results in a different fatty acid profile to that seen after LCT use. Whether this has any clinical effects is unclear.     

Metabolic clearance of a fat emulsion containing medium-chain triglycerides in cirrhotic patients.

Medium-chain triglycerides (MCTs) may be advantageous in cirrhotic patients, but data on the clearing capacity are lacking. Intravenous fat tolerance test (IVFTT) was performed on 28 cirrhotic patients (Child's A, n = 9; Child's B, n = 13; Child's C, n = 6) to determine the clearance rate of Lipofundin MCT 20%, which contains a physical mixture of MCT and long-chain triglycerides (LCT). The mean fractional elimination rate (k2) of MCT/LCT physical blend in the cirrhotic patients (7.72%/min) was comparable with that of the healthy control subjects (n = 9, k2 = 5.43%/min). Significantly higher serum free fatty acid (FFA) levels were found in the cirrhotic patients during IVFTT. The difference could be accounted for by their higher basal levels. In all patients, serum FFA concentrations returned to basal value at the end of 1 hour. Prompt appearance of glycerol and beta-hydroxybutyrate was seen during IVFTT, indicating that hydrolysis of triglycerides and release of ketone bodies from the liver were rapid. It was concluded that the ability to eliminate MCT/LCT physical blend was not impaired in the cirrhotic patients.     

Time of ingestion relative to meal intake determines gastrointestinal responses to a plant sterol–containing yoghurt drink

Purpose

Plant sterol (PS)-enriched food products are known to reduce plasma cholesterol concentrations by inhibiting the absorption of dietary and biliary cholesterol. The physiological responses induced by food intake in the gastrointestinal tract are all important factors in determining the overall effect of PS. The aim of this study was therefore to assess the effect of timing of consumption of a plant sterol (PS)–containing yoghurt drink relative to meal ingestion on gastric emptying (GE) of the drink and gallbladder (GB) volume.

Methods

This is a randomized, single-centre, controlled study with crossover design in 12 healthy male volunteers. Three treatments were tested; a 100 mL PS yoghurt drink (labeled with 1,000 mg acetaminophen) was consumed 45 min prior to, during and 45 min after a solid meal. Plasma samples were taken, and gallbladder volumes were measured at baseline and at regular intervals during a 6-h study period.

Results

When consumed before the consumption of a meal, the yoghurt drink exhibited fast GE. The solid meal intake caused a significant contraction of the gallbladder. Consumption of the PS drink before the meal had no significant effect on GB volume as compared to baseline and compared to during and after meal consumption.

Conclusions

The PS-containing drink, which empties fast from the stomach, does not sufficiently trigger gallbladder contraction without co-ingestion of a solid meal and in consequence does not induce the necessary physiological changes needed to allow PS to exhibit their effect on inhibiting cholesterol absorption.     

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.     

Fat elimination in acute renal failure: long-chain vs medium-chain triglycerides.

Elimination and hydrolysis of fat emulsions containing long-chain (LCT; Intralipid) or long- and medium-chain triglycerides (MCT; Lipofundin MCT) were compared in seven patients with acute renal failure (ARF) and six healthy control subjects. In control subjects, clearance of MCT was slightly higher than that of LCT (1.93 +/- 0.34 vs 1.55 +/- 0.3 mL.kg body wt-1.min-1, P less than 0.05). The rise in plasma triglycerides was similar and the release of free fatty acids was higher during MCT (P less than 0.02). In ARF, clearance of both LCT and MCT was equally reduced (0.53 +/- 0.12 vs 0.59 +/- 0.14 mL.kg body wt-1.min-1, P less than 0.01 vs control subjects). Again, the rise in triglycerides was comparable. Free fatty acid release was higher during MCT but lower than in control subjects. Plasma concentrations of glucose and lactate were not affected in control subjects but increased during both LCT and MCT in ARF. Thus elimination of both LCT and MCT is profoundly decreased in ARF. The impaired lipolysis in ARF cannot be circumvented by the use of MCT.     

n-3 fatty acids in psoriasis

Increased concentrations of free arachidonic acid (AA) and its proinflammatory metabolites have been observed in psoriatic lesions. Replacement of arachidonic acid by alternative precursor polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA), which can be metabolized via the same enzymatic pathways as AA, might be a therapeutic option in psoriasis. However the results of studies evaluating the therapeutic benefit of dietary fish oil have been conflicting and not clearly dose-dependent. To overcome the slow kinetics and limited availability of oral supplementation, we have performed three studies to assess the efficacy and safety of an intravenously administered fish oil derived lipid emulsion on different forms of psoriasis. Patients received daily infusions of either an n-3 fatty acid-based lipid emulsion (Omegaven) or a conventional n-6 lipid emulsion (Lipoven) in different time and dose regimens. In addition to an overall assessment of the clinical course of psoriasis, EPA- and AA-derived neutrophil 5-lipoxygenase (LO)--products, thromboxane (TX) B2/B3, PAF and plasma free fatty acids were investigated. Treatment with n-3 fatty acids resulted in a considerably higher response rate than infusion of n-6 lipids. A more than 10-fold increase in neutrophil EPA-derived 5-LO product formation was noted in the n-3 group, accompanied by a rapid increase in plasma-free EPA within the first days. In conclusion, intravenous n-3-fatty acid administration causes reduction of psoriasis, which may be related to changes in inflammatory eicosanoid generation. The rapidity of the response to intravenous n-3 lipids exceeds by orders of magnitude the hitherto reported kinetics of improvement of psoriatic lesions upon use of oral supplementation.     

中长链脂肪酸食用油对不同年龄男性高甘油三酯血症患者血脂的影响

目的探讨中长链脂肪酸食用油对不同年龄男性高甘油三酯血症患者脂代谢的影响。方法按随机双盲对照的研究方法将67名男性高甘油三酯血症患者分为中长链脂肪酸食用油组和长链脂肪酸食用油组，控制每日食用油摄入量（20～30g／d），研究前后对两组研究对象进行人体成份测量及血生化指标检测。结果中长链脂肪酸食用油组≤60岁男性在研究8周后甘油三酯（TG）、胆固醇（TC）、载脂蛋白B（apoB）、载脂蛋白AⅠ（apoAⅠ）、载脂蛋白AⅡ（apoAⅡ）、载脂蛋白CⅡ（apoCⅡ）、载脂蛋白CⅢ（apoCⅢ）、载脂蛋白E（apoE）及低密度脂蛋白胆固醇（LDL—C）降低的程度均优于长链脂肪酸食用油组（P〈0．05）；〉60岁男性TC、apoAⅠ、apoB、apoCⅡ、apoCⅢ及LDL—C降低的程度均优于长链脂肪酸食用油组（P〈0．05）。结论合理膳食条件下。中长链脂肪酸食用油可不同程度改善高TG血症患者脂代谢．有利于动脉粥样硬化的预防．