糖尿病患者中链和长链甘油三酯乳剂的清除比较

比较胰岛素非依赖性糖尿病患者中/长链甘油三酯(MCT/LCT)混合乳剂和长链甘油三酯(LCT)乳剂的清除率。每组各6例,在4小时输入脂肪期间,MCT/LCT组血甘油三酯达稳定状态。动力学参数表明MCT/LCT乳剂有着明显较小的表观分布容积和较短的半衰期。两种乳剂对血糖浓度也有不同的影响。在葡萄糖和脂肪代谢紊乱时,如需行含脂肪的肠外营养,应优先选择MCT/LCT混合乳剂。     

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...     

中链甘油三酯干预对2型糖尿病血脂和血浆游离脂肪酸的影响

目的探讨中链甘油三酯(MCT)干预对2型糖尿病(T2DM)患者体重、血脂和血浆游离脂肪酸的影响。方法以长链甘油三酯(LCT)为对照,将所有T2DM患者分为MCT组、MCT/LCT组和LCT组,在控制总能量和脂肪摄入量的基础上,3组分别连续食用100%MCT油、50%MCT油 50%LCT油和100%LCT油12周。在0、6和12周时检测血浆总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、载脂蛋白A1(ApoA1)和载脂蛋白B(ApoB)浓度以及血浆游离脂肪酸浓度。计算体质指数(BMI)、LDL/HDL、ApoA1/ApoB、总游离脂肪酸(TFFA)、长链饱和脂肪酸(LCSFA)和不饱和脂肪酸(USFA)浓度。结果在6和12周时,MCT和MCT/LCT组的体重和BMI均较LCT组低(P<0.05)。在12周时MCT/LCT组的TC水平较LCT组低(P<0.05)。与实验前相比,MCT/LCT组6和12周时的LDL-C水平均显著下降(P<0.05);与6周时相比,MCT组12周时的LDL-C水平显著下降(P<0.05)。12周时LCT组的HDL-C水平较MCT组高(P<0.05)。与MCT组相比,LCT组的LCSFA水平在6周时显著升高(P<0.05)。3组的TFFA和USFA水平差异无显著性。结论在控制总能量和脂肪摄入量的基础上,用MCT取代100%或50%的膳食油脂,患者的BMI和血脂谱得到改善,而血浆游离脂肪酸无明显变化。     

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。     

肠外营养中脂肪乳剂对红细胞膜磷脂脂肪酸组成的影响

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/LCT),以及不含脂肪乳剂对红细胞(RBC)膜磷脂肪酸组成的影响。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％的Intralipid和10％的Lypofundin提供30％的非蛋白热卡。7天后,分析RBC膜磷脂酰二极管胆硷(PC)脂肪酸组成。结果发现,不含脂肪乳剂组18:1n-9明显高于对照组;LCT组18:2n-6升高,而20:4n-6却下降;MCT/LCT组与对照组相比,脂肪酸组成变化不明显。结论:无脂肪乳剂TPN导致必需脂肪酸缺乏;LCT组由于18:2n-6的过量供给,抑制Δ6去饱和酶的活性,MCT/LCT组由于50％LCT被MCT替代,减低了对此酶活性抑制。     

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。     

肠外营养时不同脂肪乳剂对粒细胞功能的影响

目的：比较静脉输注长链及中长链脂肪乳剂对粒细胞功能的影响。方法：选择18位健康志愿进行前瞻性随机交叉对照研究，连续输注MCT／LCT或LCT（TG：0.15g.kg^-1.h^-1)，在研究前及输注中2h,4h,24h分别抽血提取多核白细胞作趋向性，自发游动，吞噬能力，杀菌率及吞噬过程中氧化代谢测定。结果：静脉输注脂肪乳剂时多核白细胞的趋向性和自发游功能力无明显改变（P＞0．05），但多核白细胞的吞噬及杀菌能力下降（P＜0．05），两种脂肪乳剂之间无统计学差异（P＞0．05）。静脉输注脂肪乳剂可明显抑制NBT值（P＜05），且LCT的抑制程度要大于MCT／LCT（P＜0．05）。结论：静脉输液脂肪乳剂可影响粒细胞吞噬，杀菌及氧化代谢能力，但对粒细胞的趋向性及自发游动能力无明显影响，长链及中／长链脂肪乳剂在对粒细胞功能的影响上无明显差异。     

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。     

含维生素E的中/长链脂肪乳注射液临床应用进展

脂肪乳剂是全胃肠外营养(TPN)中的重要组成部分.随着TPN在临床营养治疗中的广泛应用,脂肪乳剂也逐渐由长链脂肪乳(LCT)发展至中/长链脂肪乳(MCT/LCT).MCT具有水解、氧化快而完全,不依赖肉毒碱转运,对免疫系统影响少,且不易在肝内和外周组织中浸润等优点.但其中仍含有一定量的多不饱和脂肪酸,易受体内自由基的攻击而产生脂质过氧化,进而损害脂质、DNA和蛋白质,造成组织和器官的损伤.因此,许多学者主张在MCT/LCT剂中添加一定量的维生素E,以防止脂肪乳剂脂质过氧化的发生,从而保证临床安全、合理地使用脂肪乳剂进行营养治疗的同时,有效地避免发生不良反应.以下主要对含维生素E的MCT/LCT注射液在临床的应用作一综述.     

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。     

手术后病人对不同脂肪乳剂清除的影响

在创伤状态下,比较研究10% Intralipid和10% Lipofundin在血中的清除情况.结果显示,应用Lipofundin时,血中TG浓度4小时恢复至输前水平,TCH浓度与输前水平一致;应用Intralipid时,血中TG浓度6小时,TCH浓度2小时恢复至输前水平.结果显示:在一般创伤情况下,人体均能很好地清除外源性脂肪,但Lipofundin在血中的清除比Intralipid快,建议在高脂血症倾向的病人中,选用Lipofundin较为合理.     

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.     

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.     

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.     

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.     

两种中/长链脂肪乳注射液在全合一(All-in-One)营养液中的稳定性对比研究

目的研究中伥链脂肪乳注射液在全合一(All—in-One)营养液中乳粒的大小及其分布的稳定性。方法本研究采用国产的中／长链脂肪乳注射液与已进口上市的MCT／LCT脂肪乳注射液比较,分别按照相同的处方配制成全合一营养液,各自静置在25℃1天后,存放于4℃8天,再25℃静置1天,随着不同的存放条件分别在第1、2、10天取样。用光散射分光光度法和库尔特微粒测定法测定营养液中的乳粒,观察乳粒大小及其分布的变化情况。同时测定样品的pH值和渗透压,观察营养液的稳定性以及营养液体系质点数的变化情况。结果在观察期内本研究的中／长链脂肪乳注射液与进口的MCT/LCT脂肪乳注射液在全营养液中比较,其乳粒大小及分布、pH值、渗透压变化均无显差别。结论本研究的中／长链脂肪乳注射液与进口上市的MCT／LCT脂肪乳注射液在全合一(All—in—One)营养液中具有相同的稳定性。     

长链脂肪乳的临床适应证及禁忌证的分析

适应证：适宜腹部外伤病人手术后,如地震、车祸患,以便补充其适当的能量和必须的脂肪酸。禁忌症：①肝功能损害本品输入大量脂肪后,肝脏内脂肪分解成酮体增加,而生成的酮体物为酸性,对肝本身刺激,加重肝功能低下,使肝细胞的胆红素排泄受阻,肝胆小管积聚,使血中胆红素增加,同时游离的脂肪酸在血中取代胆红素与蛋白质的结合,致使黄疸加重。②血栓病 因脂肪酸具有促进血小板聚集作用,使栓塞加重,引起脑和心肌梗塞;冠心病患利用此药可诱发冠状动脉急性阻塞而导致心肌梗塞的危险。③酮尿症 酮体的优点是水溶性大,容易透过血脑屏障,为肌肉的毛细血管提供能量。 缺点是酸性强,体内积聚过多可引起代谢性酸中毒。另外酮体可使细胞外液高渗更加明显,将使糖尿病人的渗透性利尿加重,引起水和电解质的紊乱而丧失。血浆和细胞外液的高渗可能是糖尿病酮体症昏迷的主要原因。因此酮体性糖尿病是禁忌证。④中毒性休克、败血症若大量脂肪进入血液,扰乱水和电解质的平衡,血液粘滞度增加,影响微循环,加重了酸中毒。⑤高血脂症是甘油三酯产生过多,原发性高血脂或继发性高血脂症,若将50－100g脂肪静脉滴入,就会产生高上加高,所以应禁用。⑥早产儿、刚出生的婴儿、特别伴有呼吸障碍,酸中毒的新生儿,其处理脂肪的能力低下时应慎重用药。高龄患处理脂肪能力低下,必须注意安全有效用药,提高治疗水平。     

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.