Parenteral lipid emulsions and phagocytic systems

Clinical impact of lipid injectable emulsion in internal medicine inpatients exclusively receiving parenteral nutrition: a propensity score matching analysis from a Japanese medical claims database

BACKGROUND

Although guidelines recommend lipid injectable emulsions (ILEs) be used as a part of parenteral nutrition, many patients in Japan receive lipid-free parenteral nutrition. Furthermore, little is known about the effect of ILEs on clinical outcomes in medical inpatients managed with parenteral nutrition. The aim of this study was to investigate the clinical impact of ILEs on internal medicine inpatients receiving parenteral nutrition.

METHODS

A propensity score matching (PSM) analysis was performed using a medical claims database covering 451 hospitals in Japan. Participants included the following internal medicine inpatients, ages ≥ 18 years, fasting > 10 days, and receiving exclusively parenteral nutrition, between 2011 and 2020. Participants were divided into 2 groups: those who did and did not receive ILEs. The primary endpoint was in-hospital mortality. The secondary endpoints included intravenous catheter infection, activities of daily living (ADL), hospital length of stay (LOS), and total medical costs. To adjust for energy doses, logistic or multiple regression analyses were performed using energy dose as an additional explanatory variable.

RESULTS

After PSM, 19,602 matched pairs were formed out of 61,437 patients. The ILE group had significantly lower incidences than the non-ILE group of in-hospital mortality (20.3% vs. 26.9%; odds ratio [OR], 0.69; 95% confidence interval [CI], 0.66-0.72; p < 0.001), deteriorated ADL (10.8% vs. 12.5%; OR, 0.85; 95% CI, 0.79-0.92; p < 0.001), and shorter LOS (regression coefficient, - 0.8; 95% CI, - 1.6-0.0; p = 0.045). After adjusting for energy dose, these ORs or regression coefficients demonstrated the same tendencies and statistical significance. The mean total medical costs were $21,009 in the ILE group and $21,402 in the non-ILE group (p = 0.08), and the adjusted regression coefficient for the ILE vs. the non-ILE group was - $860 (95% CI, - $1252 to - $47).

CONCLUSIONS

ILE use was associated with improved clinical outcomes, including lower in-hospital mortality, in internal medicine inpatients receiving parenteral nutrition.

Three Lipid Emulsions Reduce Staphylococcus aureus-Stimulated Phagocytosis in Mouse RAW264.7 Cells

Soybean oil (SO)-, SO medium-chain triglyceride (MCT)-, olive oil (OO)-, and fish oil (FO)-based lipid emulsions are generally applied in clinical practice via intravenous injection for patients with nutritional requirements. The function of lipid emulsions on immune modulation remains inconsistent, and their effects on macrophages are limited. In the present study, we used a model of S. aureus-infected mouse RAW264.7 macrophages to determine the influence of three different compositions of lipid emulsions (Lipofundin, ClinOleic, and Omegaven) on reactive oxygen species (ROS) production, phagocytosis, and bacterial survival. The three individual lipid emulsions similarly enhanced bacterial survival but reduced S. aureus-stimulated ROS, phagocytosis of S. aureus bioparticles conjugate, polymerization of F-actin, and phosphorylation of AKT, JNK, and ERK. Compared with the JNK and ERK inhibitors, the PI3K inhibitor markedly suppressed the phagocytosis of S. aureus bioparticles conjugate and the polymerization of F-actin, whereas it significantly increased the bacterial survival. These results suggest that the three lipid emulsions diminished ROS production and phagocytosis, resulting in increased bacterial survival. PI3K predominantly mediated the inhibitory effects of the lipid emulsions on the phagocytosis of mouse RAW264.7 macrophages.

New perspective toward nutritional support for malnourished cancer patients: Role of lipids

To improve the difficulties related to malnutrition, nutritional support has become an essential part of multidisciplinary comprehensive treatment for cancer. Lipids are essential nutrient source for the human body, and nowadays in clinical practices, it has a positive interventional effect on patients suffering from cancer. However, contribution of lipids in nutritional support of cancer patients is still poorly understood. Moreover, the sensory and physicochemical properties of lipids can severely restrict their applications in lipid-rich formula foods. In this review article, for the first time, we have presented a summary of the existing studies which were related to the associations between different lipids and improved malnutrition in cancer patients and discussed possible mechanisms. Subsequently, we discussed the challenges and effective solutions during processing of lipids into formula foods. Further, by considering existing problems in current lipid nutritional support, we proposed a novel method for the treatment of malnutrition, including developing individualized lipid nutrition for different patients depending on the individual's genotype and enterotype. Nonetheless, this review study provides a new direction for future research on nutritional support and the development of lipid-rich formula foods for cancer patients, and probably will help to improve the efficacy of lipids in the treatment of cancer malnutrition.

Potential Effects of Nutraceuticals in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), the most common cause of childhood blindness, is a hypoxia-induced eye disease characterized by retinal neovascularization. In the normal retina, a well-organized vascular network provides oxygen and nutrients as energy sources to maintain a normal visual function; however, it is disrupted when pathological angiogenesis is induced in ROP patients. Under hypoxia, inadequate oxygen and energy supply lead to oxidative stress and stimulate neovasculature formation as well as affecting the function of photoreceptors. In order to meet the metabolic needs in the developing retina, protection against abnormal vascular formation is one way to manage ROP. Although current treatments provide beneficial effects in reducing the severity of ROP, these invasive therapies may also induce life-long consequences such as systemic structural and functional complications as well as neurodevelopment disruption in the developing infants. Nutritional supplements for the newborns are a novel concept for restoring energy supply by protecting the retinal vasculature and may lead to better ROP management. Nutraceuticals are provided in a non-invasive manner without the developmental side effects associated with current treatments. These nutraceuticals have been investigated through various in vitro and in vivo methods and are indicated to protect retinal vasculature. Here, we reviewed and discussed how the use of these nutraceuticals may be beneficial in ROP prevention and management.

Composition and Functionality of Lipid Emulsions in Parenteral Nutrition: Examining Evidence in Clinical Applications

Lipid emulsions (LEs), an integral component in parenteral nutrition (PN) feeding, have shifted from the primary aim of delivering non-protein calories and essential fatty acids to defined therapeutic outcomes such as reducing inflammation, and improving metabolic and clinical outcomes. Use of LEs in PN for surgical and critically ill patients is particularly well established, and there is enough literature assigning therapeutic and adverse effects to specific LEs. This narrative review contrarily puts into perspective the fatty acid compositional (FAC) nature of LE formulations, and discusses clinical applications and outcomes according to the biological function and structural functionality of fatty acids and co-factors such as phytosterols, α-tocopherol, emulsifiers and vitamin K. In addition to soybean oil-based LEs, this review covers clinical studies using the alternate LEs that incorporates physical mixtures combining medium- and long-chain triglycerides or structured triglycerides or the unusual olive oil or fish oil. The Jaded score was applied to assess the quality of these studies, and we report outcomes categorized as per immuno-inflammatory, nutritional, clinical, and cellular level FAC changes. It appears that the FAC nature of LEs is the primary determinant of desired clinical outcomes, and we conclude that one type of LE alone cannot be uniformly applied to patient care.

Lipofundin Mediates the Major Inhibition of Intravenous Propofol in IL-1β Secretion and Phagocytosis of Staphylococcus aureus-Infected Macrophages

Lipofundin is the solvent for propofol in the intravenous injection of Propofol-Lipuro® and is used in patients who need intravenous feeding to provide fatty acids and fat for energy. In addition to propofol, Lipofundin also affects the immune modulation of phagocytes. In a previous study, we reported that intravenous propofol effectively decreased Staphylococcus aureus-stimulated reactive oxygen species (ROS) levels, IL-1β secretion, and phagocytosis in RAW264.7 macrophages. It is important to separately assess the effects of pure propofol, Lipofundin, and Propofol-Lipuro. By using an S. aureus-infected RAW264.7 macrophage model, the levels of secreted IL-1β in cell supernatants were determined by ELISA. IL-1β mRNA in cell pellets was further analyzed by quantitative polymerase chain reaction (qPCR), and Western blotting was performed to detect pro-IL-1β synthesis. Total ROS levels were determined by a luminol chemiluminescence assay. Compared with pure propofol, treatment with clinically relevant concentrations of Propofol-Lipuro and Lipofundin obviously reduced IL-1β secretion (>85% inhibition), S. aureus-stimulated ROS production (50% inhibition), and phagocytosis (>60% inhibition) to similar levels. Treatment with pure propofol alone significantly decreased IL-1β mRNA levels and pro-IL-1β protein synthesis, and slightly inhibited phagocytosis. In contrast, treatment with Propofol-Lipuro did not influence IL-1β mRNA or pro-IL-1β protein expression, even though treatment with Lipofundin increased the levels of both IL-1β mRNA and its precursor protein. In conclusion, IL-1β secretion is regulated at the posttranslational level. Lipofundin mediated the major effect of Propofol-Lipuro on the inhibition of IL-1β secretion, ROS production, and phagocytosis in S. aureus-infected RAW264.7 cells.

Olive Oil and Soybean Oil Based Intravenous Lipid Emulsions, Liver Biochemistry and Clinical Outcomes

Intravenous lipid emulsions are an essential component of parenteral nutrition (PN). Omega-6 reducing strategies may improve outcomes, including reduced PN associated liver disease, however evidence to support this recommendation is insufficient. The primary objective was to compare serum alkaline phosphatase (ALP), among patients provided with either soybean oil (Intralipid) or predominantly olive oil (Clinoleic) lipid emulsions. In this quasi-experimental study, we reviewed the medical records of surgical and medical adult patients who received lipid emulsions for at least seven consecutive days. Among the 206 patients (110—Intralipid, 96—Clinoleic) there was no significant difference in ALP and remaining liver function tests within 2 weeks of PN therapy initiation between groups, even after control for lipid doses. Macronutrient dosing was similar. Triglyceride level was higher by 0.7 mmol/L in the Clinoleic group; confidence interval 0.21 to 1.1; p = 0.004. The 30-day mortality, length of hospital stay, and proportion of patients admitted to intensive care were not significantly different. The Clinoleic group had a higher infection rate (36% vs. 22%, p = 0.031) and longer intensive care stays (p = 0.045). Well-designed randomized clinical trials comparing these lipid emulsions are necessary to confirm Intralipid superiority over Clinoleic in relation to infections and serum triglycerides.

Prevention of neonatal late-onset sepsis: a randomised controlled trial

BACKGROUND

Late-onset sepsis (LOS), defined as sepsis occurring after 48 h of age causes substantial mortality and morbidity in very low birth weight infants. Risk factors for LOS include immaturity, intravascular catheters, mechanical ventilation, and prolonged parenteral nutrition (PN). Little attention has been paid to studying the effects of PN administration methods. The aim of the study was to compare a bundle of measures for PN line management incorporating a strict aseptic technique with standard line management on LOS in very low birth weight infants.

METHODS

Infants <1500 g birth weight who required PN were randomised to either a bundle of a strict aseptic technique for line management together with single use intravascular catheter for PN or a standard technique. The primary outcome was the incidence of LOS in the first 28 days of life. Secondary outcomes were mortality, neonatal morbidities and developmental outcome at 12 months of age.

RESULTS

There were 126 infants in the aseptic technique group and 123 in the standard technique group. Forty (31.8%) infants in the aseptic technique group and 36 (29.3%) in the standard technique group had an episode of sepsis (p = 0.77). This corresponds to incidences of 15.8 and 14.2 episodes of sepsis per 1000 patient days respectively. Subgroup analyses for infants <1000 g also revealed no difference in the rate of sepsis between the intervention and control groups. (p = 0.43). There were no significant differences in secondary outcomes and development between the groups.

CONCLUSION

A bundle of measures including strict aseptic technique for parenteral nutrition line management did not result in a reduction in LOS when compared to a standard technique. There is no evidence to recommend this as routine practice.

TRIAL REGISTRATION

Interdisciplinary Maternal Perinatal Australasian Collaborative Trials (IMPACT) Network, TRN registration number: PT0363. Date: 06/03/2001; Australian New Zealand Clinical Trials Registry (ANZCTR), TRN registration number: ACTRN12617000455369 . Date: 28/03/2017 (retrospectively registered).

Structured Triglyceride Emulsions in Parenteral Nutrition

Over the past 3 decades, various concepts for IV fat emulsions (IVFE) have been developed. A randomized, structured-lipid emulsion based on an old technology has recently become available. This structured-lipid emulsion is produced by mixing medium-chain triglycerides and long-chain triglycerides, then allowing hydrolysis to form free fatty acids, followed by random transesterification of the fatty acids into mixed triglyceride molecules. Studies in animals have shown an improvement in nitrogen balance with the use of these lipid emulsions. Only 8 human clinical studies with these products have been performed. The results of these human clinical studies have been less promising than the animal studies; however, an improvement in nitrogen balance and lipid metabolism exceeds results associated with infusion of long-chain triglycerides (LCT) or a physical mixture of long-chain triglycerides and medium-chain triglycerides (LCT-MCT). Structured-lipid emulsion seems to induce less elevation in serum liver function values compared with standard IVFEs. In addition, structured-lipid emulsions have no detrimental effect on the reticuloendothelial system. Further studies are necessary in order to recommend the use of structured-lipid emulsions. The clinical community hopes that chemically defined structured triglycerides will make it possible to determine the distribution of specific fatty acids on a specific position on the glycerol core and therefore obtain specific activity for a specific clinical situation.

The Acute Respiratory Distress Syndrome: Role of Nutritional Modulation of Inflammation Through Dietary Lipids

The acute respiratory distress syndrome (ARDS) is the most serious form of acute hypoxic respiratory failure. ARDS represents the expression of an acute, diffuse, inflammatory process in the lungs consequent to a variety of infectious and noninfectious conditions. It is characterized pathologically by damage to pulmonary epithelial and endothelial cells, with subsequent alveolar-capillary leak and exudative pulmonary edema. The main clinical features of ARDS include rapid onset of dyspnea, severe defects in gas exchange, and imaging studies demonstrating diffuse pulmonary infiltrates. The role of nutrition in the management of ARDS has traditionally been supportive. Recent research has demonstrated the potential of certain dietary oils (eg, fish oil, borage oil) to modulate pulmonary inflammation, thereby improving lung compliance and oxygenation, and reducing time on mechanical ventilation. This article reviews the alterations in the immune response that underlie ARDS, discusses the physiology of dietary oils as immunonutrients, summarizes animal and human studies that explore the therapeutic effects of dietary oils, and provides clinical recommendations for their use.

Toxicity of a Soybean Oil Emulsion on Human Lymphocytes and Neutrophils

BACKGROUND

The incorporation of lipid emulsions in parenteral diets is a requirement for energy and essential fatty acid supply to critically ill patients. In this study, the toxicity of a lipid emulsion rich (60%) in triacylglycerol of omega-6 polyunsaturated fatty acids on leukocytes from healthy volunteers was investigated.

METHODS

Eleven volunteers were recruited, and blood samples were collected before infusion of a soybean oil emulsion, immediately afterwards, and 18 hours later. The cells were studied immediately after isolation and again after 24 hours or 48 hours in culture. The following determinations were made: composition and concentration of fatty acids in plasma, lymphocytes and neutrophils, lymphocyte proliferation, levels of cell viability, DNA fragmentation, phosphatidylserine externalization, mitochondrial depolarization, reactive oxygen species production, and neutral lipid accumulation.

RESULTS

Soybean oil emulsion decreased lymphocyte proliferation and provoked neutrophil and lymphocyte apoptosis and necrosis. Evidence is presented herein that soybean oil emulsion is less toxic to neutrophils than to lymphocytes. The mechanism of cell death induced by this oil emulsion was characterized by mitochondrial membrane depolarization and neutral lipid accumulation but did not alter reactive oxygen species production.

CONCLUSIONS

Soybean oil emulsion given as a single dose of 500 mL promotes lymphocyte and neutrophil death that may enhance the susceptibility of the patients to infections.

A Short-Term Long-Chain Triglycerides Infusion Has No Influence on Immune Function of Adult Patients Undergoing Gastrointestinal Surgery

BACKGROUND

Parenteral nutrition (PN) support containing long-chain triglycerides (LCT) plays a critical supportive role in surgical patients' management. This study aims to investigate the effects of intravenous (IV) LCT emulsion on human immune function in adult patients receiving a gastrointestinal surgical procedure.

METHODS

Sixty adult patients were randomly assigned either to the LCT treatment group (n = 32) or to the control group (n = 28). After an abdominal operation, the subjects received PN treatment with or without LCT for 5 days. Neutrophil, peripheral blood mononuclear cell (PBMC), lymphocyte and CD4/CD8, serum immunoglobulin A (IgA), IgG, IgM, complement C3 and C4, interleukin (IL)-2, IL-4, IL-10, IL-12, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma were measured and statistically analyzed.

RESULTS

The LCT and control groups did not differ significantly at entry in terms of general features. Except for a significant increase of neutrophil number at 24 hours after the surgery in both groups (p < .01), all parameters representing the patients' immune function had no significant difference between the LCT and the control groups with respect to neutrophil and PBMC count, lymphocyte, CD4/CD8, serum IgA, IgG, IgM, complement C3, C4, IL-2, IL-4, IL-10, IL-12, TNF-alpha, and IFN-gamma (p > .05, respectively) 24 hours before the operation, and 24 hours and 120 hours after the operation.

CONCLUSIONS

The regimens of LCT administration may have diverse effects on human immune function in different patient populations. However, LCT emulsion at an appropriate dose and infusion speed does not alter human immune function of adult patients undergoing moderate gastrointestinal surgery.

Comparison of Formulas Based on Lipid Emulsions of Olive Oil, Soybean Oil, or Several Oils for Parenteral Nutrition: A Systematic Review and Meta-Analysis

Many studies have reported that olive oil-based lipid emulsion (LE) formulas of soybean oil, medium-chain triglycerides, olive oil, and fish oil (SMOF) may be a viable alternative for parenteral nutrition. However, some randomized controlled clinical trials (RCTs) have raised concerns regarding the nutritional benefits and safety of SMOFs. We searched principally the MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Scopus, EMBASE, and Cochrane Central Register of Controlled Trials databases from inception to March 2014 for the relevant literature and conducted a meta-analysis of 15 selected RCTs that 1) compared either olive oil- or SMOF-based LEs with soybean oil-based LEs and 2) reported plasma concentrations of α-tocopherol, oleic acid, and ω-6 (n-6) and ω-3 (n-3) long-chain polyunsaturated fatty acids (PUFAs) and liver concentrations of total bilirubin and the enzymes alanine transaminase, aspartate transaminase, alkaline phosphatase, and γ-glutamyl transferase. The meta-analysis suggested that SMOF-based LEs were associated with higher plasma concentrations of plasma α-tocopherol, oleic acid, and the ω-3 PUFAs eicosapentaenoic and docosahexaenoic acid. Olive oil- and SMOF-based LEs correlated with lower plasma concentrations of long-chain ω-6 PUFAs and were similar to soybean oil-based LEs with regard to their effects on liver function indicators. In summary, olive oil- and SMOF-based LEs have nutritional advantages over soybean oil-based LEs and are similarly safe. However, their performance in clinical settings requires further investigation.

Susceptibility to fatty acid-induced β-cell dysfunction is enhanced in prediabetic diabetes-prone biobreeding rats: a potential link between β-cell lipotoxicity and islet inflammation

β-Cell lipotoxicity is thought to play an important role in the development of type 2 diabetes. However, no study has examined its role in type 1 diabetes, which could be clinically relevant for slow-onset type 1 diabetes. Reports of enhanced cytokine toxicity in fat-laden islets are consistent with the hypothesis that lipid and cytokine toxicity may be synergistic. Thus, β-cell lipotoxicity could be enhanced in models of autoimmune diabetes. To determine this, we examined the effects of prolonged free fatty acids elevation on β-cell secretory function in the prediabetic diabetes-prone BioBreeding (dp-BB) rat, its diabetes-resistant BioBreeding (dr-BB) control, and normal Wistar-Furth (WF) rats. Rats received a 48-h iv infusion of saline or Intralipid plus heparin (IH) (to elevate free fatty acid levels ~2-fold) followed by hyperglycemic clamp or islet secretion studies ex vivo. IH significantly decreased β-cell function, assessed both by the disposition index (insulin secretion corrected for IH-induced insulin resistance) and in isolated islets, in dp-BB, but not in dr-BB or WF, rats, and the effect of IH was inhibited by the antioxidant N-acetylcysteine. Furthermore, IH significantly increased islet cytokine mRNA and plasma cytokine levels (monocyte chemoattractant protein-1 and IL-10) in dp-BB, but not in dr-BB or WF, rats. All dp-BB rats had mononuclear infiltration of islets, which was absent in dr-BB and WF rats. In conclusion, the presence of insulitis was permissive for IH-induced β-cell dysfunction in the BB rat, which suggests a link between β-cell lipotoxicity and islet inflammation.

Beneficial effects of the n-3 long-chain polyunsaturated fatty acids in surgical patients: updating the evidence

The use of n-3 polyunsaturated fatty acids in surgical patients has risen by the fact that this may attenuate systemic and acute inflammatory responses secondary to surgical trauma through modulation of inflammatory mediators and cell membrane interactions. Moreover, the inclusion of n-3 fatty acids in clinical trials as part of the therapy in patients, who expect to undergo a surgical stress, suggests benefits on clinical progress. Therefore, the objective of this article is to review data from n-3 polyunsaturated fatty acid effects on biochemical parameters and on reduced length of hospitalization, number of infections, and mortality as main clinical outcomes in human surgical patients.

Parenteral lipids impair pneumococcal elimination by human neutrophils

BACKGROUND

Lipid-induced modulation of phagocyte function seems to contribute to increased susceptibility to infections in patients on parenteral nutrition, and an increased risk for development of pneumonia has been observed in this group. The role of various structurally different lipid emulsions, however, remains unclear. In this study, we therefore assessed phagocyte function, as the capacity of neutrophils to eliminate Streptococcus pneumoniae (i.e. combined result of phagocytosis and killing), in the presence of these lipids.

MATERIALS AND METHODS

Neutrophils from six healthy volunteers were incubated for 1 h in emulsions (5 mmol L(-1)) derived from soybean- (LCT), fish- (VLCT), olive- (LCT-MUFA), mixed soybean/coconut oils (LCT/MCTs) or structured lipids (SL). After opsonization of the pneumococci (strain OREP-4) by human immunoglobulins, bacteria and neutrophils were incubated in the presence of complement. Next, pneumococcal elimination was evaluated and expressed as the percentage of bacteria eliminated relative to the initial bacterial numbers in neutrophil-free samples.

RESULTS

Neutrophils that were not exposed to lipids showed a pneumococcal elimination capacity of 75 +/- 3% (mean +/- SD). This significantly decreased after exposure to LCT-MUFA (70 +/- 6%), VLCT (67 +/- 2%), SL (63 +/- 9%), LCT (66 +/- 10%) and LCT/MCT (47 +/- 15%).

CONCLUSION

These data demonstrate that parenteral lipids impair the microbial elimination capacity of neutrophils in a structure-dependent manner. In accordance with our previously reported in vitro effect on a range of phagocyte functions, LCT/MCT is by far the most potent in this respect.

Non-surgical oncology - Guidelines on Parenteral Nutrition, Chapter 19

Reduced nutritional state is associated with unfavourable outcomes and a lower quality of life in patients with malignancies. Patients with active tumour disease frequently have insufficient food intake. The resting energy expenditure in cancer patients can be increased, decreased, or remain unchanged compared to predicted values. Tumours may result in varying degrees of systemic pro-inflammatory processes with secondary effects on all significant metabolic pathways. Therapeutic objectives are to stabilise nutritional state with oral/enteral nutrition and parenteral nutrition (PN) and thus to prevent or reduce progressive weight loss. The maintenance or improvement of quality of life, and the increase in the effectiveness and a reduction in the side-effects of antitumor therapy are further objectives. Indications for PN in tumour patients are essentially identical to those in patients with benign illnesses, with preference given to oral or enteral nutrition when feasible. A combined nutritional concept is preferred if oral or enteral nutrition are possible but not sufficient. There are generally no accepted standards for ideal energy and nutrient intakes in oncological patients, particularly when exclusive artificial nutrition is administered. The use of PN as a general accompaniment to radiotherapy or chemotherapy is not indicated, but PN is indicated in chronic severe radiogenic enteritis or after allogenic transplantation with pronounced mucositis or GvH-related gastrointestinal damage for prolonged periods, with particular attention to increased risk of bleeding and infection. No PN is necessary in the terminal phase.

Lipid emulsions - Guidelines on Parenteral Nutrition, Chapter 6

The infusion of lipid emulsions allows a high energy supply, facilitates the prevention of high glucose infusion rates and is indispensable for the supply with essential fatty acids. The administration of lipid emulsions is recommended within ≤7 days after starting PN (parenteral nutrition) to avoid deficiency of essential fatty acids. Low-fat PN with a high glucose intake increases the risk of hyperglycaemia. In parenterally fed patients with a tendency to hyperglycaemia, an increase in the lipid-glucose ratio should be considered. In critically ill patients the glucose infusion should not exceed 50% of energy intake. The use of lipid emulsions with a low phospholipid/triglyceride ratio is recommended and should be provided with the usual PN to prevent depletion of essential fatty acids, lower the risk of hyperglycaemia, and prevent hepatic steatosis. Biologically active vitamin E (α-tocopherol) should continuously be administered along with lipid emulsions to reduce lipid peroxidation. Parenteral lipids should provide about 25–40% of the parenteral non-protein energy supply. In certain situations (i.e. critically ill, respiratory insufficiency) a lipid intake of up to 50 or 60% of non-protein energy may be reasonable. The recommended daily dose for parenteral lipids in adults is 0.7–1.3 g triglycerides/kg body weight. Serum triglyceride concentrations should be monitored regularly with dosage reduction at levels >400 mg/dl (>4.6 mmol/l) and interruption of lipid infusion at levels >1000 mg/dl (>11.4 mmol/l). There is little evidence at this time that the choice of different available lipid emulsions affects clinical endpoints.

Biologically active oxidized lipids (phytoprostanes) in the plant diet and parenteral lipid nutrition

Phytoprostanes (PP) are autoxidation products of alpha-linolenate that are present in all plant tissues. Several classes of PP with a prostaglandin (PG) F1-, E1-, A1- and B1-like structure were identified and quantified by gas chromatography-mass spectrometry in vegetable oils and parenteral nutrition (intralipid). High levels of PP (0.09 up to 99 mg/l) were found even in apparently fresh vegetable oils. After oral consumption of olive or soybean oil, PPF1 were absorbed, found to circulate in plasma in conjugated form and excreted in free form into urine. Evidence is emerging that certain PP, such as the PPE1, may modulate the function of immune cells in a PG-like fashion. Here, we show that PPA1- and deoxy-PPJ1 display potent anti-inflammatory and apoptosis inducing activities similar to PGA1 and deoxy-PGJ2. Results of this study indicate that PP are novel, biologically active lipids in plant nutrition.

Biodistribution characteristics of mannosylated and fucosylated O/W emulsions in mice

Cell-specific drug delivery is one of the most promising strategies for improving therapeutic efficiency and minimizing systemic toxicity. Carrier systems devoted to receptor-mediated targeting need to be developed. In the case of liver-non-parenchymal cell-specific targeting systems, glycosylated emulsions have been developed as carriers for lipophilic drugs and/or peptides. This present study demonstrates the in vivo disposition behaviour and pharmacokinetic characteristics of mannosylated (Man-) and fucosylated (Fuc-) emulsions incorporated with cholesten-5-yloxy-N-(4-((1-imino-2-D-thiomannosylethyl)amino)alkyl)formamide (Man-C4-Chol) and its fucosylated derivatives (Fuc-C4-Chol), respectively. Man- (or Fuc-) emulsions are composed of soybean oil, EggPC and Man-C4-Chol (or Fuc-C4-Chol) in a weight ratio of 70:25:5. After intravenous administration to mice, these two types of [(3)H]cholesteryl hexadecyl ether (CHE)-labelled glycosylated emulsions were rapidly eliminated from the blood circulation and preferentially recovered in the liver. In contrast, bare (Bare-) emulsions composed of soybean oil:EggPC:cholesterol (Chol) in a weight ratio of 70:25:5 were more retained in the blood circulation. The hepatic uptake clearances of Man- and Fuc-emulsions were 3.3- and 4.0-times greater than that of Bare-emulsions. Interestingly, the hepatic uptake clearance of Fuc-emulsions was significantly higher that that of Man-emulsions. The uptake ratios by non-parenchymal cells (NPC) and parenchymal cells (PC) (NPC/PC ratio) for Bare-, Man- and Fuc-emulsions were found to be 0.4, 2.0 and 2.9, respectively. The hepatic uptakes of [(3)H]CHE-labelled Man- and Fuc-emulsions were reduced by pre-dosing with glycosylated proteins and liposomes. These results clearly support the conclusion that Man- and Fuc-emulsions are promising carrier systems for liver NPC-specific targeting via receptor-mediated mechanism.

Unsaturated long-chain fatty acids induce the respiratory burst of human neutrophils and monocytes in whole blood

Background

It is increasingly recognized that infectious complications in patients treated with total parenteral nutrition (TPN) may be caused by altered immune responses. Neutrophils and monocytes are the first line of defence against bacterial and fungal infection through superoxide anion production during the respiratory burst. To characterize the impact of three different types of lipid solutions that are applied as part of TPN formulations, we investigated the unstimulated respiratory burst activation of neutrophils and monocytes in whole blood.

Methods

Whole blood samples were incubated with LCT (Intralipid^®), LCT/MCT (Lipofundin^®) and LCT-MUFA (ClinOleic^®) in three concentrations (0.06, 0.3 and 0.6 mg ml^-1) for time periods up to one hour. Hydrogen peroxide production during the respiratory burst of neutrophils and monocytes was measured by flow cytometry.

Results

LCT and LCT-MUFA induced a hydrogen peroxide production in neutrophils and monocytes without presence of a physiological stimulus in contrast to LCT/MCT.

Conclusion

We concluded that parenteral nutrition containing unsaturated oleic (C18:1) and linoleic (C18:2) acid can induce respiratory burst of neutrophils and monocytes, resulting in an elevated risk of tissue damage by the uncontrolled production of reactive oxygen species. Contradictory observations reported in previous studies may in part be the result of different methods used to determine hydrogen peroxide production.

Immune modulation by parenteral lipid emulsions

Total parenteral nutrition is the final option for nutritional support of patients with severe intestinal failure. Lipid emulsions constitute the main source of fuel calories and fatty acids (FAs) in parenteral nutrition formulations. However, adverse effects on patient outcomes have been attributed to the use of lipids, mostly in relation to impaired immune defenses and altered inflammatory responses. Over the years, this issue has remained in the limelight, also because technical advances have provided no safeguard against the most daunting problems, ie, infectious complications. Nevertheless, numerous investigations have failed to produce a clear picture of the immunologic characteristics of the most commonly used soybean oil-derived lipid emulsions, although their high content of n-6 polyunsaturated FAs (PUFAs) has been considered a drawback because of their proinflammatory potential. This concern initiated the development of emulsions in which part of the n-6 FA component is replaced by less bioactive FAs, such as coconut oil (rich in medium-chain saturated FAs) or olive oil (rich in the n-9 monounsaturated FA oleic acid). Another approach has been to use fish oil (rich in n-3 PUFA), the FAs of which have biological activities different from those of n-6 PUFAs. Recent studies on the modulation of host defenses and inflammation by fish-oil emulsions have yielded consistent data, which indicate that these emulsions may provide a tool to beneficially alter the course of immune-mediated conditions. Although most of these lipids have not yet become available on the US market, this review synthesizes available information on immunologic characteristics of the different lipids that currently can be applied via parenteral nutrition support.

Modulation of lipid rafts by Omega-3 fatty acids in inflammation and cancer: implications for use of lipids during nutrition support

Current understanding of biologic membrane structure and function is largely based on the concept of lipid rafts. Lipid rafts are composed primarily of tightly packed, liquid-ordered sphingolipids/cholesterol/saturated phospholipids that float in a sea of more unsaturated and loosely packed, liquid-disordered lipids. Lipid rafts have important clinical implications because many important membrane-signaling proteins are located within the raft regions of the membrane, and alterations in raft structure can alter activity of these signaling proteins. Because rafts are lipid-based, their composition, structure, and function are susceptible to manipulation by dietary components such as omega-3 polyunsaturated fatty acids and by cholesterol depletion. We review how alteration of raft lipids affects the raft/nonraft localization and hence the function of several proteins involved in cell signaling. We focus our discussion of raft-signaling proteins on inflammation and cancer.

Inflammation as the key interface of the medical and nutrition universes: a provocative examination of the future of clinical nutrition and medicine

There has been tremendous interest in inflammation by researchers, the medical community, and the lay public. Modulation of injury response is felt to represent a tenuous balance of pro- and anti-inflammatory cytokines. Adverse outcomes may result from severe, sustained, or repeated bouts of inflammation. A critical observation is that nutrition support alone is inadequate to prevent muscle loss during active inflammation. It is necessary to take inflammation into consideration in conducting appropriate nutrition assessment, intervention, and monitoring. A host of medical conditions are actually inflammatory states that have important implications for nutrition care. Multifaceted interventions that may include anti-inflammatory diets, glycemic control, physical activity, appetite stimulants, anabolic agents, anti-inflammatory agents, anticytokines, and probiotics, will be necessary to blunt undesirable aspects of inflammatory response to preserve body cell mass and vital organ functions. Nutrition practitioners can seize this opportunity to be a part of the future medical team that brings highly individualized patient care to the bedside.

Olive oil-based lipid emulsion's neutral effects on neutrophil functions and leukocyte-endothelial cell interactions

BACKGROUND

Infection remains a drawback of parenteral nutrition (PN), probably related, among other factors, to immunosuppressive effects of its lipid component. Newer preparations may have lesser immunosuppressive impact. This study examines the effects of an olive oil-based lipid emulsion (long-chain triacylglycerols-monounsaturated fatty acids [LCT-MUFA]; ClinOleic) on various functions of human neutrophils in vitro and on rat leukocyte-endothelial cell interactions in vivo compared with LCT (Intralipid) and 50% LCT-50% medium-chain triacylglycerols (MCT; Lipofundin) mixture.

METHODS

Neutrophils isolated from healthy donors were incubated with concentrations (0.03-3 mmol/L) of lipid emulsions encompassing clinically relevant levels. In vivo leukocyte recruitment was studied with intravital microscopy within rat mesenteric microcirculation.

RESULTS

LCT-MUFA (3 mmol/L) did not alter the N-formyl-Met-Leu-Phe (FMLP)-induced rise in [Ca2+]i, oxidative burst, chemotaxis, and elastase release, whereas LCT-MCT decreased [Ca2+]i and chemotaxis and increased oxidative burst. FMLP-induced LTB4 production was augmented by lipid emulsions. Serum-opsonized zymosan-induced phagocytosis was unaltered by lipid emulsions. Basal and FMLP-induced CD11b expression was unaffected by lipid emulsions. Lipopolysaccharide (LPS)-induced TNF-alpha, IL-1beta and IL-8 mRNA, and protein expression was unaltered by LCT-MUFA, whereas LCT and LCT-MCT decreased IL-1beta mRNA and protein. LCT-MUFA did not alter apoptosis, but LCT increased apoptosis in absence and presence of GM-CSF. LPS (1 microg/mL)-induced increase in leukocyte rolling flux, adhesion, and emigration was inhibited by LCT and LCT-MCT but unaffected in LCT-MUFA-treated rats. Immunohistochemistry showed LPS-induced increase in P-selectin expression attenuated by LCT and LCT-MCT but not LCT-MUFA.

CONCLUSIONS

LCT-MUFA showed lower in vitro and in vivo impact on neutrophil function compared with LCT and LCT-MCT.

An update on parenteral lipids and immune function: only smoke, or is there any fire?

PURPOSE OF REVIEW

This paper synthesizes information from recent studies on the modulation of immune responses by lipid emulsions that are applied as part of parenteral nutrition. This issue is especially relevant in light of the high rate of infectious complications and disturbed inflammatory responses in patients receiving this form of nutritional support.

RECENT FINDINGS

Studies reporting on novel emulsions based on olive and fish oils, structured lipids or mixed-type emulsions in which various lipid species replace conventional long-chain triglycerides indicate that these lipids are generally well tolerated. While long-chain triglycerides may promote inflammation due to conversion of n-6 polyunsaturated fatty acids into arachidonic acid-derived eicosanoids, structured lipids and olive oil emulsions appear more immune-neutral. Leukocyte-activating effects of medium-chain triglycerides in experimental studies await further characterization in vivo. A body of evidence shows that immune modulation by fish oil emulsions is essentially anti-inflammatory in nature. This is in line with the observation that n-3 polyunsaturated fatty acids in fish oil replace arachidonic acid in cell membranes as an eicosanoid substrate, resulting in a decreased production of pro-inflammatory mediators. Importantly, recent investigations indicate beneficial effects of parenteral fish oil on relevant clinical outcome measures.

SUMMARY

The characteristics of, and mechanisms behind, the effects of various parenteral lipids on immune function are becoming increasingly well understood. The practical relevance of many of these findings is not immediately clear, however, and will have to be substantiated in adequately powered trials before we can translate these findings into a tailored approach for specific clinical situations.

Efficacy of Medium-chain Triglycerides Compared with Long-chain Triglycerides in Total Parenteral Nutrition in Patients with Digestive Tract Cancer Undergoing Surgery

The objectives of this prospective, randomized study were to evaluate the efficacy and tolerability of the short-term use of medium-chain triglyceride/long-chain triglyceride (MCT/LCT) fat emulsions, and to compare the hematologic and biochemical effects of MCT/LCT fat emulsions with LCT fat emulsions in gastrointestinal (GI) tract cancer patients following surgery. Thirty patients with GI tract cancer requiring total parenteral nutrition (TPN) were equally randomized to receive MCT/LCT or LCT emulsions for 7 days. After 7 days, no sign of complications directly related to administration of fat emulsions was observed and there were no marked differences in anthropometry, length of hospital stay, and surgical complication rates between the two groups. However, MCT/LCT significantly improved plasma prealbumin concentration (p = 0.005). Changes in complements C3 and C4, total lymphocyte count, and immunoglobulins after TPN were not significantly different between the groups. Serum triglyceride and cholesterol levels remained constant. The serum insulin level in the MCT/LCT group was higher than in the LCT group (p = 0.048). Our data revealed that MCT/LCT fat emulsions significantly enhanced nutritional status in patients with GI tract cancer, indicated by higher prealbumin levels, which might be partially due to the higher circulating insulin levels in the MCT/LCT group.

Lipid emulsions potently increase transgene expression in hepatocytes after adenoviral transfer

Elimination of Kupffer cells by cytotoxic clodronate liposomes increases transgene expression in the liver after adenoviral transfer. Here, we demonstrate that empty l-alpha-phosphatidylcholine liposomes block uptake of vectors in the reticuloendothelial cells of the liver and increase human apolipoprotein (apo) A-I (approved gene symbol apo A-I) expression in C57BL/6 (1.3-fold) and Balb/c mice (3.1-fold) to the same extent as clodronate liposomes (1.5- and 3.4-fold, respectively). A similar elevation of human apo A-I levels was induced by the lipid emulsion Intralipid (1.5- and 2.8-fold in C57BL/6 and Balb/c mice, respectively). Not only Kupffer cells but also hepatic sinusoidal endothelial cells (HSEC) constitute the reticuloendothelial cells of the liver. The uptake of adenoviral vectors 1 h after transfer in C57BL/6 mice was 2.9-fold lower in Kupffer cells than in HSEC. In contrast, Kupffer cell uptake in Balb/c mice was 2.6-fold higher than in HSEC. Vector uptake in reticuloendothelial cells of the liver was reduced and transgene expression was increased in splenectomized and Rag2-deficient Balb/c mice but not in splenectomized and Rag1-deficient C57BL/6 mice. In conclusion, lipid emulsions for parenteral clinical use block uptake of adenoviral vectors by the reticuloendothelial cells of the liver and potently increase transgene expression.

Propofol use precludes prescription of estimated nitrogen requirements

The objective was to determine whether reducing enteral nutrition to accommodate 1% Propofol-derived energy results in suboptimal nitrogen prescription. This was a prospective observational study of 85 consecutive patients requiring mechanical ventilation and receiving 1% Propofol. Enteral nutrition prescription often failed to meet nitrogen requirements (<90%, in 50.6%; <80%, in 21.1%), whereas fat provided 51% of total energy input, exceeding 2 g fat/kg/d in 20%. However, gastroparesis was common, resulting in suboptimal nutrition (median of requirements: energy 71%; nitrogen 57%). If energy balance had been strictly maintained, substituting 1% with 2% Propofol would reduce the number of patients failing to meet nitrogen requirements (1% vs 2%: <90%: in 58.8% vs 17.6%, P< .001; <80% in 35.3% vs 4.7%, P< .014). These effects are directly related to the amount of fat delivered with Propofol. Intensive care unit-associated gastroparesis commonly reduces enteral nutrition input. However, even where this is overcome, use of 1% Propofol frequently precludes prescription of estimated nitrogen requirements; either 2% Propofol or a non-Propofol alternative should be considered.

Efficacy and safety of an olive oil-based intravenous fat emulsion in adult patients on home parenteral nutrition

BACKGROUND

The most frequently used intravenous lipid emulsions are composed of 100% long chain triacylglycerols from soybean oil or of 50% long chain triacylglycerols-50% medium chain triacylglycerols. A newer emulsion, ClinOleic 20% containing 80% olive oil and 20% soybean oil, was suggested to reduce lipid peroxidation and immune function impairment.

AIM

To assess ClinOleic 20%'s efficacy, safety and effect upon systemic inflammatory parameters in adults on home parenteral nutrition.

METHODS

In stable home parenteral nutrition patients, the initial intravenous lipid emulsion was changed for ClinOleic 20%. Nutritional status, clinical and biological tolerance, and systemic inflammatory markers were analysed before and after 1 and 3 months of home parenteral nutrition, with ClinOleic 20% as intravenous lipid emulsion.

RESULTS

Clinical and biological nutritional markers and inflammatory parameters did not differ between day 0 and month +3. There was no essential fatty acids deficiency. No side-effects were reported. Three of five patients presenting with migraine during home parenteral nutrition infusion at day 0 felt consistently better at month +3.

CONCLUSIONS

ClinOleic 20% is safe and efficient in adult home parenteral nutrition. It maintains normal essential fatty acids status and did not influence inflammatory parameters. In contrast to studies in preterm infants or paediatric patients, no effect on vitamin E concentration or lipid peroxidation was observed.

Oil-in-water lipid emulsions: implications for parenteral and ocular delivering systems

Lipid emulsions (LEs) are heterogenous dispersions of two immiscible liquids (oil-in-water or water-in-oil) and they are subjected to various instability processes like aggregation, flocculation, coalescence and hence eventual phase separation according to the second law of thermodynamics. However, the physical stability of the LE can substantially be improved with help of suitable emulsifiers that are capable of forming a mono- or multi-layer coating film around the dispersed liquid droplets in such a way to reduce interfacial tension or to increase droplet-droplet repulsion. Depending on the concentrations of these three components (oil-water-emulsifier) and the efficiency of the emulsification equipments used to reduce droplet size, the final LE may be in the form of oil-in-water (o/w), water-in-oil (w/o), micron, submicron and double or multiple emulsions (o/w/o and w/o/w). The o/w type LEs (LE) are colloidal drug carriers, which have various therapeutic applications. As an intravenous delivery system it incorporates lipophilic water non-soluble drugs, stabilize drugs that tend to undergo hydrolysis and reduce side effects of various potent drugs. When the LE is used as an ocular delivery systems they increase local bioavailability, sustain the pharmacological effect of drugs and decrease systemic side effects of the drugs. Thus, the rationale of using LE as an integral part of effective treatment is clear. Following administration of LE through these routes, the biofate of LE associated bioactive molecules are somehow related to the vehicles disposition kinetics inside blood or eyeball. However, the LE is not devoid from undergoing various bio-process while exerting their efficacious actions. The purpose of this review is therefore to give an implication of LE for parenteral and ocular delivering systems.

Meta-analysis of parenteral nutrition versus enteral nutrition in patients with acute pancreatitis

OBJECTIVE

To compare the safety and clinical outcomes of enteral and parenteral nutrition in patients with acute pancreatitis.

DATA SOURCES

Medline, Embase, Cochrane controlled trials register, and citation review of relevant primary and review articles.

STUDY SELECTION

Randomised controlled studies that compared enteral nutrition with parenteral nutrition in patients with acute pancreatitis. From 117 articles screened, six were identified as randomised controlled trials and were included for data extraction.

DATA EXTRACTION

Six studies with 263 participants were analysed. Descriptive and outcome data were extracted. Main outcome measures were infections, complications other than infections, operative interventions, length of hospital stay, and mortality. The meta-analysis was performed with the random effects model.

DATA SYNTHESIS

Enteral nutrition was associated with a significantly lower incidence of infections (relative risk 0.45; 95% confidence interval 0.26 to 0.78, P = 0.004), reduced surgical interventions to control pancreatitis (0.48, 0.22 to 1.0, P = 0.05), and a reduced length of hospital stay (mean reduction 2.9 days, 1.6 days to 4.3 days, P < 0.001). There were no significant differences in mortality (relative risk 0.66, 0.32 to 1.37, P = 0.3) or non-infectious complications (0.61, 0.31 to 1.22, P = 0.16) between the two groups of patients.

CONCLUSIONS

Enteral nutrition should be the preferred route of nutritional support in patients with acute pancreatitis.

Rapid alterations of serum fatty acids with the intravenous administration of an arachidonate solution

Polyunsaturated fatty acids (PUFAs) have been shown to possess a considerable anti-tumor and anti-bacterial effect in vitro. In an attempt to achieve serum concentrations of these acids similar to those applied in vitro, a solution of ethyl ester of arachidonic acid (AA) was administered intravenously at 25 mg/kg within 10 min in six male rabbits. Blood samples were collected before and 60 min after infusion from catheters inserted in the hepatic veins and in the carotid artery. Analysis of serum fatty acids was performed by gas chromatography mass spectrometry. Elevated concentrations of elongated fatty acids were detected in the hepatic veins after infusion. Mean concentrations of arachidonate in the hepatic veins and the carotid arteries after infusion of AA were 2.77 and 3.73 microM, respectively. It is concluded that the intravenous administration of a solution of AA might result in increased hepatic biosynthesis of serum saturated and unsaturated fatty acids of elongated carbon chains. The increasing interest for the application of PUFAs in therapeutics renders further study mandatory to clarify the significance of these findings.