不同碳链脂肪乳剂对肝脏外科病人术后的影响

目的观察两种不同碳链脂肪乳剂对肝脏外科病人术后自然病程的影响。方法选择肝脏外科病人25例，随机分为两组；长链脂肪乳剂组（n＝12，简称LCT组），中／长链脂肪乳剂组（n=13，简称MCT组）。LCT组脂肪乳剂为20％Inralipid，MCT组为20％Lipofundin，连续观察1周。在术前，术后1、4、7天测定肝功能、血脂、血及尿液中肉毒碱（CNT）以及激素的变化。结果两组对肝脏酶学无明显影响。胆红素在术后1天明显升高，但MCT组随后显著下降，LCT组下降速度慢于MCT组，P＜0．05。PN期间血脂代谢无异常。CNT术后明显升高，尿排出减少，术后7天LCT组血CNT高于MCT组，尿CNT低于MCT组，P＜0．05。血皮质醇、胰岛素（I）、G以及G／I术后第1天均明显升高，随后逐渐下降，而LCT组术后7天，胰高糖素（G）以及G／I维持在较高水平。血糖术后明显升高，术后4、7天，LCT组持续在较高水平，MCT组已属正常。结论MCT／LCT乳剂可能是肝脏外科病人更为理想的脂肪能源。     

长链脂肪乳剂及中/长链脂肪乳剂水解速率的比较研究

目的：比较长链脂肪乳剂、物理混合的中／长链脂肪乳剂及结构脂肪乳剂的水解速率。方法：应用1、^14C甘油棕榈酸标记的长链三酰甘油（LCT）和2，3－^3H甘油辛酸标记的中链三酰甘油（MCT），分别标记Intralipid,Lipofundin及Structolipid，在体外添加缓冲液、脂蛋白酯酶和肝酯酶后，置37℃温箱中水浴、卵育。采用气相色谱仪测定核素核记的各种脂肪酸及三酰甘油浓度，游离脂肪酸浓度用放射性核素扫描计数测定，通过计算培养液中^14C标记的长链脂肪酸及^3H标记的中链脂肪酸分别在^14C标记LCT及^3H标记MCT中的比例。来计算三种脂肪乳剂的水解率。结果：物理混合的中／长链脂肪乳剂及结构脂肪乳剂的水解程度明显高于长链脂肪乳剂，差异有统计学意义。物理混合的中／长链脂肪乳剂水解程度高于结构脂肪乳剂，但在水解程度及水解速度上却无统计学差异。结论：物理混合的中／长链脂肪乳剂及结构脂肪乳剂的水解率明显高于长链脂肪乳剂。     

静脉输注长链及中/长链脂肪乳剂对脂蛋白代谢的影响

目的比较静脉输注长链(LCT)及中长链(MCT/LCT)脂肪乳剂时血浆脂蛋白代谢.方法选择12例健康志愿者进行前瞻性随机交叉对照研究, 连续输注MCT/LCT或LCT6小时(0.20g TG.Kg-1@h-1),测定研究前及输注中4h、6h、8h、12h及24h时血清TG、FFA,PL、FC、CE浓度以及血浆各脂蛋白成份.结果脂肪乳剂输注过程中,MCT/LCT组血清甘油三酯(TG)浓度明显低于LCT组,而血浆FFA浓度约为LCT组的3倍(p<0.001), MCT/LCT 的半衰期明显短于[LCT (68(12)分钟vs.(116(18)分钟,p<0.05].LCT组血浆游离胆固醇浓度明显高于MCT/LCT 组(p<0.05),而血浆胆固醇酯(CE)浓度在研究过程中两组均无明显变化.结论MCT/LCT的水解、代谢清除率要明显高于LCT,MCT/LCT输注时TG与LDL之间转换率较高,脂肪颗粒较少获取CE,其残余颗粒的清除也高于LCT.     

结构脂肪乳剂与物理混合的中/长链脂肪乳剂脂肪酸代谢比较研究

目的:比较结构脂肪乳剂(STG)与物理混合的中/长链脂肪乳剂(MCT/LCT)在人体内的脂肪酸代谢情况.方法:40例健康志愿者随机分为STG组和MCT/LCT组,每组20例.分别于早晨6h内匀速输注20%力文脂肪乳剂和20%力保肪宁脂肪乳剂1.0 g/(kg·次).并于给药前和给药后2、4、6和24 h留取血标本测定血...     

新生儿肝功能障碍时不同脂肪乳剂对血脂和肝功能影响的比较研究

目的 :比较中 /长链和长链脂肪乳剂对肝功能障碍新生儿血脂和肝功能的影响。　方法 :将 40例血清胆红素水平≥ 5 1.3μmol/L(3mg % )的新生儿随机分成两组 ,分别应用中 /长链脂肪乳剂 (MCT/LCT组 ,2 0 %Lipo fundin)和长链脂肪乳剂 (LCT组 ,2 0 %Intralipid) ,剂量均为 2 g/ (kg·d) ,持续 1周。在实验前、后分别抽血测定血脂和肝功能。　结果 :两组总胆固醇无显著变化 ,甘油三酯在LCT组升高 ,在MCT/LCT组下降 ,与实验前相比均无显著差异 ,组间比较MCT/LCT非常显著地低于LCT组。胆红素在两组均显著下降 ,但MCT/LCT组下降比LCT组更加显著。γ GT和ALP在LCT组无明显改变 ,但在MCT/LCT组却有显著降低 ,并显著低于LCT组。　结论 :在危重新生儿合并有肝功能障碍时 ,应用中 /长链脂肪乳剂显著优于长链脂肪乳剂。     

肠外营养中脂肪乳剂对红细胞变形性的影响

利用大鼠胃肠外营养（PN）模型观察长链脂肪乳剂（LCT），中链／长链脂肪乳剂（MCT／TCT），以及不含脂肪乳剂对红细胞变形性的影响。PN总热量为300kcal·kg-1·d-1，非蛋白热卡：氮为182：1，LCT组、MCT／LCT组分别由10％Intralipid和10％Lipofundin提供30％的非蛋白热卡。7天后，分析红细胞膜磷脂脂肪酸组成和用激光衍射法测定红细胞变形性。结果发现，尽管红细胞膜磷腊脂肪酸组成发生改变，由于脂肪酸饱和度变化不大，红细胞变形性无改变。     

不同浓度脂肪乳剂短时输注对术后病人脂代谢的影响

因胆囊炎、胆石症行单纯胆囊切除术的患者10例，随机分为静脉输注10％脂肪乳剂（A组）和20％脂肪乳剂（B组）两组。围手术期给予不同浓度脂肪乳剂的营养支持（PN）5天。结果显示：两组病人SGPT均有轻度增高，但与输注前比较尤显著差异；A组AKP、r-GT有轻度增高，而B组有轻度下降，但两组比较无统计学意义。血浆Tch、TG变化无统计学意义；B组HDL有显著下降（P＜0.05）；A组LDL有升高，但与输注前比较P＜0．05，与B组比较无统计学意义。     

静脉输注长链或中长链脂肪酸脂肪乳剂对急性坏死性胰腺炎大鼠脂质介质的影响

目的：探讨静脉输注长链或中长链脂肪酸脂肪乳剂对急性坏死性胰腺炎（ANP）大鼠血浆脂质介质及胰腺病理改变的影响。方法：雄性SD大鼠43只随机入组，A－C为非胰腺炎组：A组为正常组；B组正常大鼠输注脂肪乳剂；C组为手术对照组，输注葡萄糖液。D－F为ANP模型组：分别为全糖组，Intralipid组和Lipofundin组。测定A组血淀粉酶、前列腺素类，胰腺行病理学检查。测定B－F组术后4、48及72h血淀粉酶、前列腺素类，胰腺病理学检查并评分。结果：正常大鼠输注Intralipid不引起血前列腺素的变化。在胰腺炎各组，脂肪乳剂可提高4h6－keto-PGF1α、PGE2血浆浓度；Lipofundin组胰腺组织的出血和脂肪坏死明显减少。结论：脂肪乳剂不加重ANP大鼠胰腺组织病理损害；LCT／MCT脂肪乳剂更适合应用于ANP。     

结构脂肪乳剂改善腹部手术后病人的氮平衡和蛋白质代谢

目的:观察结构脂肪乳剂(STG)和物理混合的中、长链脂肪乳剂(MCT/LCT)对腹部中等及中等以上手术创伤病人氮平衡和蛋白质代谢的影响.方法:腹部中等及中等以上手术病人随机分为两组,术后第2天开始分别使用STG和MCT/LCT构成的等氮、等热量肠外营养支持5天,术后第1天至第6天留取标本检测氮平衡,术前、术后第1天及术后第6天抽取静脉血检测血清前清蛋白水平,术前及术后第6天称取体质量,记录住院日.结果:围手术期使用STG和MCT/LCT的静脉营养,均可以纠正创伤病人的负氮平衡,促进血清前清蛋白的合成.其中STG可以更明显地改善手术创伤病人的负氮平衡,增加血清前清蛋白水平,但在维持病人体质量和缩短住院日上,STG与MCT/LCT脂肪乳相比差异并不明显.结论:在改善手术创伤病人的蛋白质代谢上,STG比物理混合的MCT/LCT脂肪乳剂更加优越.     

肠外营养中脂肪乳剂抑制肝脂肪变性的机理

210克左右Wistar大鼠随机分为五组，在LCT组、MCT／LCT组、GS组中进行等氮、等热量肠外营养（PN）。总热量为300kcal·kg－1·d-1，非蛋白热能：氮＝182：1，LCT组、MCT／LCT组分别由10％的Intralipid和10％的Lipofundin提供30％的非蛋白热卡，7天后，分别测定血脂和肝脂，测定血浆生化指标，并行肝脏病理检查。结果显示：GS组肝细胞胞浆内出现弥漫的脂肪浸润，而LCT组、MCT／LCT组的肝细胞与对照组类似，无脂肪变性。探讨PN中脂肪乳剂抑制肝脂防变性的机理，是由于脂肪乳剂中必需脂肪酸（EFA）使肝脏内的脂肪合成减少，脂肪运出增加，通过代谢调节避免了肝脏脂肪变性。     

Phagocyte-induced lipid peroxidation of different intravenous fat emulsions and counteractive effect of vitamin E.

Unsaturated fatty acids, a major component of fat emulsions used in parenteral nutrition, are prone to peroxidation which is an important feature of oxygen-associated tissue damage. We used the nitroblue tetrazolium (NBT) reduction test to measure the production of superoxide radicals by stimulated polymorphonuclear neutrophils (PMN) in the presence of different fat emulsions: Intralipid (containing 100% long-chain triacylglycerols, LCT), Vasolipid (a physical mixture of 50% LCT and 50% medium-chain triacylglycerols, MCT) and Structolipid (structured triacylglycerols containing 63% LCT and 37% MCT). We measured the amount of malonaldehyde (MDA) and 4-hydroxyalkenal to determine the lipid peroxidation of the three fat emulsions in the presence of stimulated neutrophils. Further, we investigated the role of vitamin E (alpha-tocopherol) in preventing lipid peroxidation in vitro. The results showed that the values of NBT reduction of PMN were significantly decreased in each of the three fat emulsions and that increasing concentrations of fat emulsions were associated with decreased values of NBT reductions, in a dose-dependent way (P<0.001). There were, however, no statistically significant differences between the values of the three different types of fat emulsions (P>0.05). Lipid peroxidation increased significantly in the presence of all three types of fat emulsions, and was more pronounced for Intralipid than for Vasolipid and Structolipid after 1 and 2 h of incubation with resting as well as with stimulated phagocytes. The increased lipid peroxidation of the fat emulsions was markedly reduced by vitamin E, and the inhibition was concentration dependent. In conclusion, lipid peroxidation in vitro is more pronounced when PMNs are incubated with fat emulsions. This increase in lipid peroxidation can be reduced by adding vitamin E to the fat emulsions.     

Effects of structurally different lipid emulsions on human neutrophil migration

AIM: To test the hypothesis that structurally different lipid emulsions have distinct immunomodulatory properties, we analysed neutrophil migration in the presence of various lipid emulsions. METHOD: Neutrophils of 8 volunteers were pre-incubated in medium or physiological 2.5 mM emulsions containing long-chain (LCT), medium-chain (MCT), mixed LCT/MCT, alpha -tocopherol-enriched LCT/MCT (LCT/MCT-E) or structured triglycerides (SL). Thereafter, the cells were put on top of 3 microm-pore-sized cell culture filters and incubated for one hour in the presence or absence of a chemo-attractant. Neutrophil migration was measured as the percentage of cells that had passed the filter in the presence (chemotaxis) or absence (random migration) of a chemotactic factor. RESULTS: Compared to lipid-free incubation (19+/-1%) random neutrophil migration significantly decreased with LCT/MCT (11+/-2%), LCT/MCT-E (12+/-2) and MCT (5+/-2%), while LCT (18+/-3%) and SL (20+/-1%) had no effect. N-formyl-methionyl-leucyl-phenylalanine- (fMLP, 10(-8)M) or zymosan-activated-serum-induced (ZAS, 10%) filter passage under lipid-free conditions amounted to 61+/-14% and 70+/-13%, respectively. These values decreased with LCT/MCT to 11+/-9% and 15+/-7%; with LCT/MCT-E to 18+/-10% and 28+/-12%; with SL to 39+/-18% and 57+/-14%, and with MCT to 5+/-2% and 10+/-6%, (all P<0.01), while LCT had no effect. Compared to LCT/MCT, the alpha -tocopherol-enriched formulation significantly increased ZAS- and fMLP-induced chemotaxis. fMLP-induced chemotaxis decreased in direct proportion to LCT/MCT triglyceride concentration. Conclusions: Human neutrophil migration is distinctively inhibited by structurally different lipid emulsions, depending on triglyceride chain-length and concentration as well as alpha -tocopherol content.     

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.     

静脉输注脂肪乳剂对成人呼吸窘迫综合征的影响

脂肪乳剂中长链甘油三酯所含多价不饱和脂肪酸是多种生物活性物质（如前列腺素等）的前体，它们在成人呼吸窘迫综合征（ARDS）发病中起着极为重要的作用。长链甘油三酯用于ARDS患者可出现一过性动脉血氧分压下降和肺内分流增加，故应慎重大量使用；中链甘油三酯不含生物活性物质前体，但有较高生热作用，故宜慢速输注。理论上长链和中链甘油三酯混合输往或调整多价不饱和脂肪酸比例及使用方法，从而调控生物活性物质的产生，可对ARDS患者起一定的治疗作用。     

Fat emulsions in parenteral nutrition after liver transplantation: The recovery of the allografts RES function and histological observations

Following liver transplantation, the effect of post-operative parenteral nutrition with MCT LCT (Medium Chain Triglycerides/Long Chain Triglycerides) fat emulsions on the recovery of allografts RES function was investigated in a randomised prospective study of three groups of patients (group I, n = 14: 50g MCT LCT fats twice weekly, group II, n = 15: 0.7 g/kg body weight per day MCT LCT fats, group III, n = 17: 1.5 g/kg body weight per day MCT LCT fats). RES function was assessed using the (99m)Tc-HSA-MM-Clearance ((99m)Technitium-Human serum albumen-Millimicrosphere-Clearance). There were no statistically significant differences in the recovery of RES function between the groups. A negative effect on RES function as a result of the administration of MCT LCT fat emulsions up to 1.5 g/kg b.w. per day can therefore be excluded. The evaluation of liver biopsies before the administration of fats and at the end of TPN (Total Parenteral Nutrition) showed no evidence, in the 20 patients investigated, of any fatty changes in the liver caused by the infusion of fat.     

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.     

Comparison of metabolic clearance rates of MCT/LCT and LCT emulsions in diabetics

In seven moderately overweight noninsulin-dependent diabetics with slightly elevated triglyceride levels, disappearance rates of infused medium chain triglyceride/long chain triglyceride (MCT/LCT) and long chain triglyceride (LCT) emulsions were compared. Five metabolically healthy volunteers served as controls. During a 3-hr lipid infusion, serum triglycerides reached a steady state with both emulsions in the healthy controls, whereas, in diabetic patients, steady state triglyceride levels were seen only with MCT/LCT. After the end of the lipid infusion, the longest half-life value in the decline of triglyceride levels was found with LCT in diabetics, whereas significantly shorter and quite similar half-life values were found with LCT in healthy controls and with MCT/LCT in diabetics. As expected, the shortest half-life for serum triglycerides was found in healthy controls after MCT/LCT-infusion. Virtually the same differences in serum concentrations and in half-life times were seen with free fatty acids. According to these data, if needed, parenteral nutrition with lipids in states of disturbed glucose and lipid metabolism may preferentially be done with MCT/LCT emulsions.     

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).     

Phagocytosis and killing of Candida albicans by human neutrophils after exposure to structurally different lipid emulsions

BACKGROUND: To test the hypothesis that structurally different lipid emulsions have distinct immune-modulating properties, we analyzed the elimination of Candida albicans by neutrophils after exposure to various emulsions. METHODS: Neutrophils from 8 volunteers were incubated in physiologic 5 mmol/L emulsions containing long-chain- (LCT), medium-chain- (MCT), mixed LCT/MCT-, alpha-tocopherol-enriched LCT/MCT (LCT/MCT-E), or structured lipids (SL). After washing, the neutrophils were incubated with C. albicans. Phagocytosis was measured as the number of yeast-associated neutrophils relative to the total neutrophil count. Killing was expressed as the percentage of Candida survival relative to the initial yeast cell count. RESULTS: No significant differences in yeast-neutrophil association could be demonstrated after neutrophil incubation in various lipid emulsions or medium, after correction for non-specific adhesion. However, although Candida survival after 1 hour incubation with non-lipid-exposed neutrophils amounted to 53% +/- 11% and was not influenced by LCT (60% +/- 11%), LCT/MCT (78% +/- 7%), LCT/MCT-E (72% +/- 12%), and SL (67% +/- 6%), pure MCT (70% +/- 13%) significantly impaired the killing capacity of neutrophils. CONCLUSIONS: The decreased killing capacity of neutrophils after exposure to medium-chain fatty acid-containing emulsions and the absence of this effect with LCT suggest that lipid emulsions influence the elimination of C. albicans depending on the triglyceride chain length.