Statement on guidelines for total parenteral nutrition

This is one of a series of clinical guidelines. They represent a consensus statement dealing with optimum patient care in significant clinical areas. The statement has been prepared by the Patient Care Committee, with the advice of other experts and with peer review. As with all such guidelines, they should be interpreted in a nondogmatic manner, so as not to exclude other therapies or opinions in any particular situation. Based on present knowledge, limited at times, future modifications or other changes in these guidelines may be necessary.Patient Care Committee—Stanley B. Goldberg, MD, Chairman. Members: John A. Balint, MD; H. Worth Boyce, MD; Thomas H. Browning, MD; James N. Cooper, MD; David Earnest, MD; Emanuel Freidman, MD; Martin Greene, MD; Walter Jacobs, MD; Mark H. Mellow, MD; Henry A. Pitt, MD; Jane L. Todaro, MD.     

Effects of Saccharomyces boulardii on fecal short-chain fatty acids and microflora in patients on long-term total enteral nutrition

AIM: To assess the effects of Sb on fecal flora and short-chain fatty acids (SCFA) in patients on long-term TEN. METHODS: Ten patients (3 females, 7 males, 59±5.5 years), on TEN for a median of 13 mo (1-125), and 15 healthy volunteers (4 females, 11 males, 32±2.0 years) received Sb (0.5 g bid PO) for 6 d. Two stool samples were taken before, on the last 2 d and 9-10 d after treatment, for SCFA measurement and for culture and bacterial identification. Values (mean±SE) were compared using sign tests and ANOVA. RESULTS: Fecal butyrate levels were lower in patients (10.1±2.9 mmol/kg) than in controls (19.2±3.9, P= 0.02). Treatment with Sb increased total fecal SCFA levels in patients (150.2±27.2 vs 107.5±18.2 mmol/kg, P= 0.02) but not in controls (129.0±28.6 vs 113.0±15.2 mmol/kg, NS). At the end of treatment with Sb, patients had higher fecal butyrate (16.0±4.4 vs 10.1 [2.9] mmol/kg, P= 0.004). Total SCFAs remained high 9 d after treatment was discontinued. Before the treatment, the anaerobe to aerobe ratio was lower in patients compared to controls (2.4±2.3 vs 69.8±1.8, P= 0.003). There were no significant changes in the fecal flora of TEN patients. CONCLUSION: Sb-induced increase of fecal SCFA concentrations (especially butyrate) may explain the preventive effects of this yeast on TEN-induced diarrhea.     

Impact of postoperative omega-3 fatty acid-supplemented parenteral nutrition on clinical outcomes and immunomodulations in colorectal cancer patients

AIM： To investigate the effect of omega-3 fatty acid parenteral supplementation postoperatively on clinical outcomes and immunomodulation in colorectal cancer patients. METHODS： Forty-two patients undergoing radical colorectal cancer resection with an indication for total parenteral nutrition postoperatively were enrolled in this prospective, double-blind, randomized, controlled study. Patients received total parenteral nutrition supplemented with either soybean oil （LCT; Intralipid, Fresenius-Kabi, SO group, n = 21） or a combination of omega-3 fish oil and soybean oil （LCT：fish oil = 5：1, fish oil; Omegaven, Fresenius-Kabi, FO group, n = 21）, up to a total of 1.2 g lipid/kg per day for 7 d postoperatively. A same volume calorie and nitrogen was administrated. Routine blood test, biochemistry, systemic levels of IL-6 and TNF-α, percentage of CD3＋, CD4＋, and CD8＋ lymphocytes were evaluated preoperatively and on postoperative d 1 and 8. Patient outcome was evaluated considering mortality during the hospital stay, length of postoperative hospital stay, and occurrence of infectious complications. RESULTS： Both lipid regimens were well tolerated. No differences between the two groups were noticed in demographics, baseline blood test, biochemistry, serum levels of IL-6 and TNF-α, percentage of CD4＋, CD8＋ lymphocytes, and ratios of CD4＋/CD8＋. Compared with those on postoperative d 1, serum IL-6 levels onpostoperative d 8 were significantly depressed in the FO group than in the reference group （-44.43 ± 30.53 vs -8.39 ± 69.08, P = 0.039）. Simultaneously, the ratios of CD4＋/CD8＋ were significantly increased in the FO group （0.92 ± 0.62 vs 0.25 ± 1.22, P = 0.035）. In addition, depression of serum TNF-α levels （-0.82 ± 2.71 vs 0.27 ± 1.67, P = 0.125） and elevation of CD3＋ and CD4＋ lymphocyte percentage （12.85 ± 11.61 vs 3.84 ± 19.62, P = 0.081, 17.80 ± 10.86 vs 9.66 ± 17.55, P = 0.084, respectively） were higher in the FO group than in the reference g     

Hepatotoxicity of intravenous Cyclosporin A in patients with acute ulcerative colitis on total parenteral nutrition

Abstract: A group of 24 patients underwent a 7–14-day course of continuously infused Cyclosporin A (2 mg · kg^-1 · day^-1) to treat a severe attack of ulcerative colitis. In 19 of them, including eight treated with total parenteral nutrition, we retrospectively analyzed the serum aminotransferase (AST/ALT) levels at the beginning and at the end of Cyclosporin infusion. The baseline levels of AST/ALT in the group were 19.9±3.2 and 31.4±6.4; on stopping Cyclosporin infusion, they were 43±15.8 and 119±56, respectively. Six patients showed an ALT change above 1.5 times the upper limit of reference. They included five of the eight patients treated with total parenteral nutrition (62.5%). In one of the six, ALT rose to 1000 U/l and was accompanied by full-blown febrile cholangitis (proven by liver biopsy). This episode was preceded by excessive accumulation of Cyclosporin in blood. The development of liver toxicity was independent of the length of Cyclosporin treatment, nor did it impair drug efficacy. Thus, in these patients total parenteral nutrition and Cyclosporin were synergistic, causing twice the frequency of liver damage (62.5%) reported for ulcerative colitis patients on total parenteral nutrition alone (37%). Total parenteral nutrition should not be used to support patients needing Cyclosporin for autoimmune disease. However, too high a dose of Cyclosporin may cause liver disease per se.     

Stimulation of ileal emptying by short-chain fatty acids

We have shown previously that short-chain fatty acids (mixtures of acetic, propionic, and butyric acids; SCFAs) in the proportions found usually in stool water stimulate fasting ileal motility. Based on indirect evidence, we proposed that these motor patterns (bursts of phasic pressure waves that were propagated) would be propulsive, but the capacity of these stimulated patterns of motility to propel contents has not been established directly. Healthy, surviving dogs were provided with motility sensors and a cannula through which SCFAs could be instilled into the ileum. Boluses of SCFAs were much more likely to stimulate phasic bursts of motility than was saline. Scintigraphic studies using a gamma camera showed that the motility stimulated by SCFAs was propulsive and that the ileum was thereby emptied. We also tested whether SCFAs were equally effective stimuli during fasting and after food. SCFAs were equally effective during fasting and soon after food, but in the late postprandial period, when the meal reached the ileum, SCFAs were much less likely to stimulate motility. These observations shed further light on the capacity of the ileum to sense and react to the nature of the contents.     

An experimental study on cell dynamic alteration in digestive organs following total parenteral nutrition in dogs

To investigate the effects of total parenteral nutrition (TPN) on the alimentary tract, liver and pancreas, dogs were kept under TPN for 3 weeks, and changes in the cell dynamics of those organs and gastrointestinal hormones were evaluated. DNA synthesis activity in the mucosa of the stomach, jejunum and ileum decreased after TPN, and these changes recovered after oral refeeding. However, in the non-mucosal structures of the gastrointestinal wall, liver and pancreas, no corresponding changes were observed. Serum gastrin concentration was lowered after TPN, and it recovered after oral refeeding. A positive correlation was observed between serum gastrin level and DNA synthesis activity in the mucosa of the stomach, jejunum and ileum at all periods. However, enteroglucagon and pancreatic glucagon in the blood did not show any changes after TPN. In conclusion, TPN-induced changes in cell dynamics in the mucosa of the alimentary tract are reversible after resumption of oral feeding, and the serum gastrin release may be a regulating factor in these changes. A part of this study was presented at the 25th Annual Meeting of the Japanese Society of Surgical Metabolism and Nutrition (at Tokyo, Japan in July, 1988) and at the 75th General Meeting of the Japanese Society of Gastroenterology (at Yokohama, Japan in March, 1989).     

Rapid intravenous administration of amino acids prevents biliary sludge induced by total parenteral nutrition in humans

The aim of this study was to evaluate whether daily rapid intravenous administration of amino acids (IVAA) prevented the formation of biliary sludge in humans receiving long-term total parenteral nutrition (TPN). Thirty adult patients receiving TPN for more than 28 consecutive days were studied. They were randomized to receive either saline solution (placebo) intravenously (15 patients) or 6.9% branched chain amino acid (BCAA)-enriched amino acid (15 synthetic amino acids; Freamine HBC) solution given by administration rapid intravenous (15 patients). The groups were similar with respect to age, sex, diagnosis, liver function test results, amylase levels, TPN time, and time of study. All patients underwent weekly ultrasound studies. Volume and emptying studies of the gallbladder in response to the study drug were performed after 1 week. As a result, none of the patients receiving rapid IVAA had sludge, whereas 11 of the 15 patients receiving placebo had sludge (P < 0.01). Results of emptying studies showed significant contraction of the gallbladder in those in the rapid IVAA group, but not in the placebo group. Consequently, the data suggest that rapid IVAA given daily prevents TPN-induced stasis and sludge in the gallbladder. We conclude that rapid IVAA should be used as routine prophylaxis against biliary sludge and formation of gallstones in patients receiving long-term TPN.     

Total parenteral nutrition impairs bile flow and alters bile composition in newborn piglet

Cholestatic liver disease complicates total parenteral nutrition (TPN) in premature neonates. We investigated TPN-induced liver disease in the newborn piglet, hypothesizing that: (1) TPN impairs bile flow by reducing the bile acid-dependent (BADF) and the bile acid-independent component of bile flow (BAIF); and (2) TPN changes bile composition. For three weeks, eight piglets received TPN and nine piglets were fed milk. Basal bile flow was measured and bile composition analyzed for bile acids, cholesterol (C), phospholipids (PL), and PL fatty acids. Bile flow was also measured after stimulation with 20, 50, and 100 µmol/kg taurocholic acid (TCA). Liver histology and bilirubin content were examined. Basal bile flow was reduced from 11.6±1.2 µl/g liver/10 min in orally fed animals to 1.6±0.4 µl/g liver/10 min in the TPN group. The stimulated bile flow in the TPN group did not respond to TCA and was lower than in the orally fed animals at each TCA dose. Both BADF and BAIF were significantly lower in the TPN group. Bile acid secretion was less than 50% of control values and total C and PL secretions were less than 5% of control. Liver and serum bilirubin were elevated in the TPN group. The newborn piglet is a valid model to study TPN-induced cholestasis, characterized by decreased bile acid secretion, impaired BADF and BAIF, and reduced bile flow stimulation after intravenous TCA.Supported by grants from the Medical Research Council of Canada, and the Children's Health Foundation of Northern & Central Alberta, Edmonton, Canada.     

A study of the ameliorating effects of carnitine on hepatic steatosis induced by total parenteral nutrition in rats

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急性胰腺炎全胃肠外营养和肠内营养的荟萃分析

目的 为明确全胃肠外营养（TPN）和肠内营养（EN）对急性胰腺炎（AP）患者的作用，对有关比较TPN和EN在AP中作用的文献进行荟萃分析。方法 检索1966年到2004年6月问发表的有关TPN和EN治疗AP的随机对照临床试验。按人选标准，有8项临床试验纳入本研究，由2名评价者对入选研究中有关试验设计、研究对象的特征、研究结果等内容独立进行摘录，并用RevMan4．2软件进行分析。结果 EN与TPN比较，能显著降低感染发生率（RR=0．45，95％CI为0．29～0．68，P=0．0002）及感染以外并发症发生率（RR=0．67，95％CI为0．47～0．96，P=0．03），减少手术干预（RR=0．47，95％CI为0．24～0．94，P=0．03），并有缩短住院时间的趋势，但不能降低死亡率（RR=0．61，95％CI为0．32～1．18，P=0．14）。结论 AP患者应首先考虑选用EN作为常规治疗，而不支持TPN。     

Treatment of distal ulcerative colitis with short-chain fatty acid enemas a placebo-controlled trial

Rectal enemas containing a short-chain fatty acid mixture, butyrate alone, or saline placebo were administered to 47 patients with active distal ulcerative colitis. Enemas were instilled twice daily and the patients' condition was evaluated at entry and after four and eight weeks of local therapy. A disease activity index, chosen as the major end point, decreased significantly after all three modes of treatment with no difference among groups. The endoscopic appearance of the mucosa and the histologic degree of inflammation was not different among groups. After eight weeks, fewer colonic segments were affected endoscopically following butyrate than placebo treatment. This study showed trends towards a beneficial effect of topical short-chain fatty acids in active ulcerative colitis, but more patients are needed to demonstrate this effect with sufficient statistical power.This study was sponsored by Dr. Falk Pharma, Freiburg, Germany.The study group consisted of the following members: W. Scheppach, H.-P. Bartram, F. Richter, Department of Medicine, University of Würzburg; J.G. Müller, Department of Pathology, University of Würzburg; R. Greinwald, H.-D. Tauschel, Dr. Falk Pharma, Freiburg; M. Gierend, A. Weber, Medicomp GmbH, Ulm; D. Hegemann, Frino Comp, Geretsried; W. Kubetzko, Vitalis-Klinik, Bad Hersfeld; U. Rabast, Elisabeth Krankenhaus, Hattingen; E. Schütz, Gastroenterological Practice, Regensburg; R. Raedsch, St Josefs-Hospital, Wiesbaden; R. Britsch, Gastroenterological Practice, Mannheim; I.H. Rehmann, Gastroenterological Practice, Lippstadt; P. Otto, Krankenhaus Grossburgwedel, Burgwedel; G. Judmaier, Department of Medicine, University of Innsbruck, Austria; A.G. Press, Department of Medicine, University of Göttingen; D. Wördehoff, St. Michael-Krankenhaus, Völklingen; H. Mlitz, Gastroenterological Practice, Saarbrücken; J. Stein, Medical Clinic II, University of Frankfurt; and C. Schmidt, Medical Policlinic, University of Bonn.     

Aspergillus galactomannan antigen levels in allogeneic haematopoietic stem cell transplant recipients given total parenteral nutrition

Abstract: False-positive tests for Aspergillus galactomannan have been reported in neutropenic patients. We failed to detect any circulating antigen during the 2 weeks following allogeneic haematopoietic stem cell transplantation of 12 patients who had severe mucositis but were unable to eat.     

Disturbances in essential fatty acid metabolism in patients receiving long-term home parenteral nutrition

Patients receiving home total parenteral nutrition (HTPN) are at risk for the development of essential fatty acid deficiency (EFAD). This study examined the essential fatty acid status of patients on long-term HTPN for gut failure. Serum phospholipid and triglyceride fatty acids were measured in 11 patients and 10 healthy volunteers. Patients had similar levels of linoleic acid (18:2w6) in serum triglyceride fatty acids but significantly lower levels of 18:2w6 in serum phospholipids compared to controls. Although there was accumulation of Mead acid (20:3w9) in both fatty acid fractions, the ratio of 20:3w9 to arachidonic acid (20:4w6) remained less than 0.2, reflecting an adequate essential fatty acid status in these patients. There were, however, substantial increases in 20:4w6 content in both triglyceride and phospholipid fractions in serum despite the lower levels of 18:2w6 in serum phospholipids, suggesting that an accelerated hepatic conversion of 18:2w6 to 20:4w6 occurs in HTPN patients, as well as the 20-carbon members of w3 (20:3w3) and w9 (20:3w9) families. The determination of optimal parenteral fat intakes should be investigated further as important priority in patients receiving long term HTPN.     

全肠外营养诱导线粒体应激介导的肝细胞凋亡的研究

目的探讨全肠外营养诱导新生乳猪线粒体应激介导的肝细胞凋亡的作用机制。方法以肠内营养乳猪作为对照,建立全肠外营养新生乳猪实验动物模型,喂养7d后获取肝脏组织,分离原代肝细胞,部分肝组织应用琼脂糖凝胶电泳检测肝细胞DNA凋亡条带,通过凋亡蛋白活性测定、免疫组织化学、Western blot印迹法等检测全肠外营养诱导肝细胞发生凋亡的蛋白表达。结果全肠外营养组乳猪肝细胞活率为（49±21）％,明显低于肠内营养组的（88±14）％（P〈0．05）。全肠外营养乳猪肝组织DNA电泳呈现典型梯形凋亡条带,细胞凋亡ELISA检测发现细胞凋亡定量高达对照组的2．6倍,半胱天冬氨酸蛋白酶（caspase）-3活性也明显升高,与肠内营养相比增高9．9倍,但ATP酶活性下降了24％。Westernblot显示全肠外营养组肝组织中相关凋亡蛋白酶PARP、caspase-9和-7蛋白酶原被活化,Bcl-2蛋白表达量下调,Bax蛋白量表达上调;同时线粒体内细胞色素C释放至胞浆内,使胞浆内细胞色素C表达水平升高。免疫组织化学也显示全肠外营养组Bax表达上调。结论全肠外营养可以损伤肝组织,并通过线粒体应激信号传导通路诱导肝细胞凋亡。     

Chronic liver disease in children on long-term parenteral nutrition

Use of long-term total parenteral nutrition (TPN) is often presumed to be associated with serious hepatic dysfunction. In this retrospective study, we reviewed the complete charts of patients who had received TPN for more than 2.5 years, starting in infancy or childhood, for evidence of liver dysfunction. There were 16 male and 10 female patients with a total of 254.5 patient years on TPN. Seventeen patients have been on TPN since birth or early infancy. Thirteen of 26 patients derive ≥90% of their calorie intake from TPN. Six patients had hepatomegaly; two of them also had splenomegaly. Twenty-one patients had normal transaminases, nine have had past episodes of raised enzymes ranging from 2.5 to 7.5 times normal. Seventeen patients always had normal bilirubin levels, five had past episodes of hyperbilirubinaemia, while four patients had persistently raised bilirubin levels (range 1.5–20.7 g/dL). Alkaline phosphatase was normal for age in all patients except two. Hepatic synthetic function, as measured by albumin, pre-albumin levels and prothrombin time, was within the normal range in all patients except one. Liver biopsies were performed in eight patients. Two biopsies showed cirrhosis, one showed chronic active hepatitis (CAH) with cholestasis, two patients had fibrosis, one showed cholestasis and two biopsies were normal. One patient with cirrhosis and one with CAH were positive for hepatitis C antibody. Another asymptomatic patient was positive for hepatitis B. Only the patient with CAH had hepatic decompensation. We conclude that clinical hepatic failure is uncommon in our group of patients on long-term TPN for 2.5 years or more. Cirrhosis and fibrosis, when found, could not be solely attributed to TPN.     

肠内营养与肠外营养对重症急性胰腺炎患者肠屏障功能影响的比较

目的 研究肠内与肠外营养对重症急性胰腺炎(SAP)患者肠屏障功能的影响.方法 苏州大学附属第一医院、上海交通大学附属第一医院、无锡市第二人民医院及泰州市人民医院4家单位符合SAP入选标准的63例患者随机分为肠内营养(EN)组及全肠外营养(TPN)组.其中,29例接受EN,经鼻空肠管给予高能肠内营养液;34例接受TPN,通过静脉补充营养液.观察两组患者的血清内毒素、二胺氧化酶(DAO)水平及尿乳果糖/甘露醇(L/M)比值的变化.结果 在第7、14、21天,EN组血清内毒素水平均明显低于TPN组[(39.30±15.82)EU/L比(73.05±21.16)EU/L、(22.64±14.31)EU/L比(49.34±24.54)EU/L、(14.81±10.93)EU/L比(30.08±14.10)EU/L,P值均＜0.05];在第7、14天,EN组的血浆DAO水平均明显低于TPN组[(9.97±3.84)U/L比(19.89±9.89)U/L、(5.42±1.84)U/L比(8.79±4.08)U/L,P值均＜0.05];在第7、14、21天,EN组的尿L/M比值明显低于TPN组(0.28±0.25比0.65±0.45、0.21±0.18比0.54±0.41、0.08±0.04比0.29±0.06,P值均＜0.05).结论 EN在改善肠屏障功能方面优于TPN.

Abstract：

Objective To evaluate the effect of enteral nutrition (EN) versus total parenteral nutrition(TPN) on gut barrier function in patients with severe acute pancreatitis (SAP). Methods Sixtythree patients with SAP enrolled from 4 hospitals were randomly assigned into EN group(29 cases) and TPN group(34 cases). EN group patients were fed via a spiral nasojejunal feeding tube placed routinely by endoscopy or fluoroscopy, and TPN group patients were nourished intravenously with TPN during the same period. The changes of serum endotoxin, diamine oxidase, and urinary excretion of lactulose and mannitol ratio (L/M) were observed. Results Plasma concentration of endotoxin were markedly decreased in EN group as compared with that in TPN group at the 7th,14th ,21th day of entry trial [(39. 30 ± 15. 82) EU/L vs (73.05 ±21.16) EU/L,(22.64 ±14.31) EU/L vs (49.34 ±24.54) EU/L,(14.81 ± 10.93)EU/L vs ( 30. 08 ± 14. 10 ) EU/L, P ＜ 0. 05]. Plasma concentration of diamine oxidase were markedly decreased in EN group as compared with that in TPN group at the 7th, 14th day of entry trial [(9. 97 ± 3. 84)U/Lvs (19.89±9.89)U/L,(5.42±1. 84) U/Lvs (8.79 ±4.08) U/L, both P ＜ 0. 05]. The urinary L/M decreased significantly in EN group than those in TPN group at the 7th, 14th,21th day of entry trial (0.28 ±0.25 vs 0. 65 ±0.45,0.21 ±0. 18 vs 0.54 ±0.41,0.08 ±0.04 vs 0.29 ±0.06, all P＜0.05).Conclusion EN has better effect on improving intestinal barrier function than TPN in treatment of patients with SAP.     

ω-3 fatty acid-enriched parenteral nutrition shortens hospital stay in acute variceal bleeding cirrhotic patients

Acute variceal bleeding, a crucial complication of liver cirrhosis requires high energy expenditures but gastrointestinal bleeding limits enteral feeding in the acute stage. We investigated the safety and efficacy of ω-3 fatty acid-enriched parenteral nutrition in acute variceal bleeding patients.In this retrospective study, a total of 208 cirrhotic patients with acute variceal bleeding who underwent parenteral nutrition in the absence of enteral nutrition were enrolled. Among the patients, 86 patients received ω-3 fatty-acid-enriched parenteral nutrition. The primary endpoint was to evaluate the duration of hospital stay and the presence of clinical complications of liver cirrhosis.The mean age of the patients enrolled was 54.9 years-old and 185 patients (88.9%) were male. The cause of liver cirrhosis, Child-Pugh score and comorbidities were statistically not different. Patients with ω-3 enriched parenteral nutrition had a significantly lower systolic blood pressure and total bilirubin levels. The difference in the in-hospital mortality (P = .813) or rate of complications (P = .880) was not statistically significant. The duration of hospital stay was significantly shorter in the patients who underwent ω-3 fatty acid-enriched parenteral nutrition (10.7 ± 7.3 vs 7.9 ± 4.2 days, P = .001).In liver cirrhosis patients with acute variceal bleeding, ω-3 fatty acid-enriched parenteral nutrition significantly decreased the length of hospital stay. Further prospective studies to consolidate these findings are warranted.     

Effect of coadministration of parenteral multivitamins with lipid emulsion on lung remodeling in an animal model of total parenteral nutrition

Exposure of parenteral multivitamin solutions (MVP) to ambient light generates peroxides and vitamin loss, and induces initiation of fibrosis and a reduced alveolar count in an animal model of total parenteral nutrition (TPN). Adding MVP to the lipid moiety of TPN prevents lipid peroxidation and vitamin loss. The aim of the study was to compare modes of delivery of MVP on lung procollagen mRNA and alveolar counts. Three-day-old guinea pig pups were infused continuously with one of three intravenous solutions: 1) control = dextrose; 2) AA + MVP = MVP given with the dextrose + amino-acid moiety, in a "piggyback" setup with a lipid emulsion mixed close to the infusion site; and 3) LIP + MVP = same as AA + MVP, except that MVP is given with the lipid emulsion. After 4 days, lungs were prepared for alveolar count (intercept technique) and for quantification of the procollagen/beta-actin mRNA ratio (initial step of fibrosis). Data were compared by ANOVA. The procollagen mRNA was lower (P < 0.05) in animals receiving LIP + MVP than those with AA + MVP. But the two modes of admixture of MVP had the same effect on the alveolar counts, which were lower (P < 0.01) than controls. The mode of delivery of TPN affects lung remodeling. Although LIP + MVP protects against the initiation of lung fibrosis, the absence of a beneficial effect on alveolar counts suggests that these features of lung remodeling are not caused by a unique component of TPN. Specific roles of peroxides, components of MVP, and light exposure on lung remodeling need to be explored before LIP + MVP can be recommended as an alternative mode of parenteral vitamin delivery.     

Morbid obesity and type 2 diabetes alter intestinal fatty acid uptake and blood flow

Aims

Bariatric surgery is the most effective treatment to tackle morbid obesity and type 2 diabetes, but the mechanisms of action are still unclear. The objective of this study was to investigate the effects of bariatric surgery on intestinal fatty acid (FA) uptake and blood flow.

Materials and Methods

We recruited 27 morbidly obese subjects, of whom 10 had type 2 diabetes and 15 were healthy age‐matched controls. Intestinal blood flow and fatty acid uptake from circulation were measured during fasting state using positron emission tomography (PET). Obese subjects were re‐studied 6 months after bariatric surgery. The mucosal location of intestinal FA retention was verified in insulin resistant mice with autoradiography.

Results

Compared to lean subjects, morbidly obese subjects had higher duodenal and jejunal FA uptake (P < .001) but similar intestinal blood flow (NS). Within 6 months after bariatric surgery, obese subjects had lost 24% of their weight and 7/10 diabetic subjects were in remission. Jejunal FA uptake was further increased (P < .03). Conversely, bariatric surgery provoked a decrease in jejunal blood flow (P < .05) while duodenal blood flow was preserved. Animal studies showed that FAs were taken up into enterocytes, for the most part, but were also transferred, in part, into the lumen.

Conclusions

In the obese, the small intestine actively takes up FAs from circulation and FA uptake remains higher than in controls post‐operatively. Intestinal blood flow was not enhanced before or after bariatric surgery, suggesting that enhanced intestinal FA metabolism is not driven by intestinal perfusion.