Narrative Review of n-3 Polyunsaturated Fatty Acid Supplementation upon Immune Functions, Resolution Molecules and Lipid Peroxidation.

Fish oil supplementation is commonplace in human nutrition and is being used in both enteral and parenteral formulations during the treatment of patients with a large variety of diseases and immune status. The biological effects of fish oil are believed to result from their content of n-3 polyunsaturated fatty acids (PUFA), particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). These fatty acids are known to have numerous effects upon immune functions and are described as immunomodulatory. However, immunomodulatory is a nondescript term that encompasses immunostimulation and immunosuppression. The primary goal of this review is to better describe the immune effects of n-3 PUFA as they relate to immunostimulatory vs. immunosuppressive effects. One mechanism proposed for the immune effects of n-3 PUFA relates to the production of specialized pro-resolving mediators (SPMs). A second goal of this review is to evaluate the effects of n-3 PUFA supplementation upon production of SPMs. Although n-3 PUFA are stated to possess anti-oxidative properties, these molecules are highly oxidizable due to multiple double bonds and may increase oxidative stress. Thus, the third goal of this review is to evaluate the effects of n-3 PUFA upon lipid oxidation. We conclude, based upon current scientific evidence, that n-3 PUFA suppress inflammatory responses and most cellular immune responses such as chemotaxis, transmigration, antigen presentation, and lymphocyte functions and should be considered immunosuppressive. n-3 PUFA induced production of resolution molecules is inconsistent with many resolution molecules failing to respond to n-3 PUFA supplementation. n-3 PUFA supplementation is associated with increased lipid peroxidation in most studies. Vitamin E co-administration is unreliable for prevention of the lipid peroxidation. These effects should be considered when administering n-3 PUFA to patients that may be immunosuppressed or under high oxidative stress due to illness or other treatments.

Biological and Clinical Aspects of an Olive Oil-Based Lipid Emulsion-A Review.

Intravenous lipid emulsions (ILEs) have been an integral component of parenteral nutrition for more than 50 years. Numerous formulations are available and are based on vegetable (soybean, olive, coconut) and animal (fish) oils. Therefore, each of these formulations has a unique fatty acid composition that offers both benefits and limitations. As clinical experience and our understanding of the effects of fatty acids on various physiological processes has grown, there is evidence to suggest that some ILEs may have benefits compared with others. Current evidence suggests that olive oil-based ILE may preserve immune, hepatobiliary, and endothelial cell function, and may reduce lipid peroxidation and plasma lipid levels. There is good evidence from a large randomized controlled study to support a benefit of olive oil-based ILE over soybean oil-based ILE on reducing infections in critically ill patients. At present there is limited evidence to demonstrate a benefit of olive oil-based ILE over other ILEs on glucose metabolism, and few data exist to demonstrate a benefit on clinical outcomes such as hospital or intensive care unit stay, duration of mechanical ventilation, or mortality. We review the current research and clinical evidence supporting the potential positive biological and clinical aspects of olive oil-based ILE and conclude that olive oil-based ILE is well tolerated and provides effective nutritional support to various PN-requiring patient populations. Olive oil-based ILE appears to support the innate immune system, is associated with fewer infections, induces less lipid peroxidation, and is not associated with increased hepatobiliary or lipid disturbances. These data would suggest that olive oil-based ILE is a valuable option in various PN-requiring patient populations.

Subcutaneous Infusion of Fluids for Hydration or Nutrition: A Review.

Subcutaneous infusion, or hypodermoclysis, is a technique whereby fluids are infused into the subcutaneous space via small-gauge needles that are typically inserted into the thighs, abdomen, back, or arms. In this review, we provide an overview of the technique, summarize findings from studies that have examined the use of subcutaneous infusion of fluids for hydration or nutrition, and describe the indications, advantages, and disadvantages of subcutaneous infusion. Taken together, the available evidence suggests that, when indicated, subcutaneous infusion can be effective for administering fluids for hydration or nutrition, with minimal complications, and has similar effectiveness and safety to the intravenous route. Of note, subcutaneous infusion offers several advantages over intravenous infusion, including ease of application, low cost, and the lack of potential serious complications, particularly infections. Subcutaneous infusion may be particularly suited for patients with mild to moderate dehydration or malnutrition when oral/enteral intake is insufficient; when placement of an intravenous catheter is not possible, tolerated, or desirable; at risk of dehydration when oral intake is not tolerated; as a bridging technique in case of difficult intravenous access or catheter-related bloodstream infection while infection control treatment is being attempted; and in multiple settings (eg, emergency department, hospital, outpatient clinic, nursing home, long-term care, hospice, and home).

Safety and Efficacy of Subcutaneous Parenteral Nutrition in Older Patients: A Prospective Randomized Multicenter Clinical Trial.

BACKGROUND: Many patients who cannot tolerate adequate enteral nutrition could benefit from parenteral nutrition support but fail to receive it due to difficult intravenous (IV) access. The objective of this study was to compare the safety and efficacy of subcutaneous (SC) administration of parenteral nutrition with the peripheral IV route. MATERIALS AND METHODS: This was a prospective randomized multicenter study of 121 older hospitalized patients. The primary outcome was the composite end point of major local side effects, defined as local edema, blistering, erythema, phlebitis, cellulitis, unbearable pain, or route failure requiring a switch in route. Secondary outcomes were nutrition parameters, biochemical parameters, clinical outcomes, and safety. RESULTS: The SC route (n = 59) was noninferior to the IV route (n = 61) for major local side effects. Major local side effects trended higher in the IV group ( P = .059). Local edema was more common in the SC group ( P < .05), while route failure was more common in the IV group ( P < .001). Nutrition and biochemical parameters, safety, and clinical outcomes were similar between groups. CONCLUSIONS: The SC route of nutrient administration was better tolerated than the peripheral IV route. SC administration of parenteral nutrition represents a safe alternative to IV nutrition.

Distribution of Tocopherols and Tocotrienols in Guinea Pig Tissues Following Parenteral Lipid Emulsion Infusion.

BACKGROUND: Tocopherols and tocotrienols possess vitamin E activity and function as the major lipid-soluble antioxidants in the human body. Commercial lipid emulsions are composed of different oils and supply different amounts of vitamin E. The objective of this study was to measure all 8 vitamin E homologs within 4 different commercial lipid emulsions and evaluate their distribution in guinea pig tissues. MATERIALS AND METHODS: The distribution of vitamin E homologs within plasma and guinea pig tissues was determined using a high-performance liquid chromatography (HPLC) system. Lipid hydroperoxides in lipid emulsions were determined using a commercial kit (Cayman Chemical Company, Ann Arbor, MI), and malondialdehyde tissue levels were determined using an HPLC system. RESULTS: The lipid emulsions contained variable amounts of tocopherols, which were significantly different between emulsions. Tocotrienols were present at very low concentrations (≤0.3%). We found no correlation between the amount of vitamin E present in the lipid emulsions and lipid peroxidation. Hydroperoxides were the lowest with an olive oil-based emulsion and highest with a fish oil emulsion. The predominant vitamin E homolog in guinea pig tissues was α-tocopherol. No tissues had detectable levels of tocotrienols. Vitamin E levels (primarily α-tocopherol and γ-tocopherol) were highly variable among organ tissues. Plasma levels were a poor reflection of most tissue levels. CONCLUSION: Vitamin E levels within different lipid emulsions and plasma/tissues are highly variable, and no one tissue or plasma sample serves as a good proxy for levels in other tissues. All study emulsions were well tolerated and did not significantly increase systemic lipid peroxidation.

Safety and efficacy of an olive oil-based triple-chamber bag for parenteral nutrition: a prospective, randomized, multi-center clinical trial in China.

BACKGROUND: Small studies suggest differences in efficacy and safety exist between olive oil-based (OLIVE) and soybean oil-based (SOYBEAN) parenteral nutrition regimens in hospitalized adult patients. This large, prospective, randomized (1:1), open-label, multi-center, noninferiority study compared the delivery, efficacy, and safety of OLIVE (N = 226) with SOYBEAN (N = 232) in Chinese adults (≥18 years) admitted to a surgical service for whom parenteral nutrition was required. METHODS: Treatments were administered for a minimum of 5 days up to 14 days (to achieve approximately 25 kcal/kg/day, 0.9 g/kg/day amino acids, 0.8 g/kg/day lipid). Impact of treatment on anabolic/catabolic and serum inflammatory, chemistry, and hematological markers, safety, and ease of use were assessed. The primary efficacy variable was serum prealbumin level at Day 5. RESULTS: OLIVE (n = 219) was not inferior to SOYBEAN (n = 224) based on the prealbumin least square geometric mean [LSGM] ratio [95% CI] 1.12 [1.06, 1.19]; P = 0.002), improved the anabolic/catabolic status of patients enrolled in the study, and was well tolerated compared with SOYBEAN. Improved anabolic status was supported by significantly higher levels of prealbumin at Day 5, albumin at Day 5 and IGF-1 at Day 14 in the OLIVE group, while catabolism was similar between groups. C-reactive protein, intercellular adhesion molecule-1, procalcitonin, and oxidation were similar in each group, but infections were significantly lower with OLIVE (3.6% versus 10.4%; P < 0.01). CONCLUSIONS: OLIVE provided effective nutrition, was well tolerated, was associated with fewer infections, and conferred greater ease-of-use than SOYBEAN. TRIAL REGISTRATION: NTC 01579097.

Comparative study of the modulation of fructose/sucrose-induced hepatic steatosis by mixed lipid formulations varying in unsaturated fatty acid content.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in developed countries. NAFLD encompasses a spectrum of diseases, ranging from hepatic steatosis to non-alcoholic steatohepatitis (NASH), cirrhosis, and liver failure. The etiology of NAFLD remains unclear but is thought to relate to increased fatty acid flux within the liver that results in toxic fatty acid metabolite production. One source of increased fatty acid flux is fructose/sucrose-induced hepatic lipogenesis. Current treatment for NAFLD encompasses dietary modifications. However, little scientific evidence exists on which to base many dietary recommendations, especially the intake of different types of carbohydrates and fats. We hypothesized that lipid mixtures of unsaturated fatty acids would inhibit lipogenesis and subsequent hepatic steatosis induced by high carbohydrate diets. The aim of this study was to examine the effects of different complex mixtures of fatty acids upon the development of fructose/sucrose-induced hepatic steatosis. METHODS: C57BL/6 mice were randomized to normocaloric chow-based diets that varied in the type of carbohydrate (starch, sucrose, fructose). Animals in each carbohydrate group were further randomized to diets that varied in lipid type (no additional lipid, soybean oil, fish oil, olive/soybean oil, macadamia nut oil). These oils were chosen based upon their content of omega-6 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, omega-9 monounsaturated fatty acids, or omega-7 monounsaturated fatty acids. Fatty acid flux in the liver was determine by assessing hepatic lipid content (steatosis). We also assessed fatty acid levels in the plasma and liver of the animals, hepatic lipogenesis activity, hepatic stearoyl-CoA-1 desaturase activity, and hepatic elongase activity. RESULTS: Animals consumed similar amounts of the diets and maintained normal body weights throughout the study. Both sucrose and fructose induced hepatic lipogenesis and steatosis, with fructose being more potent. All mixed lipids similarly inhibited steatosis, limiting lipid content to levels found in the control (starch) animals. Lipogenesis and stearoyl-CoA-1 desaturase activity were increased in the sucrose and fructose groups. Levels of these enzymatic processes remained at baseline in all of the lipid groups. CONCLUSION: This is the first study to compare various complex lipid mixtures, based upon dietary oils with different types of long-chain fatty acids, upon development of sucrose/fructose-induced steatosis. Both carbohydrate source and lipid content appear important for the modulation of steatosis. Moderate intake of complex lipids with high unsaturated to saturated fatty acid ratios inhibited both lipogenesis and steatosis.

Phytosterols, Lipid Administration, and Liver Disease During Parenteral Nutrition.

Phytosterols are plant-derived sterols that are structurally and functionally analogous to cholesterol in vertebrate animals. Phytosterols are found in many foods and are part of the normal human diet. However, absorption of phytosterols from the diet is minimal. Most lipid emulsions used for parenteral nutrition are based on vegetable oils. As a result, phytosterol administration occurs during intravenous administration of lipid. Levels of phytosterols in the blood and tissues may reach high levels during parenteral lipid administration and may be toxic to cells. Phytosterols are not fully metabolized by the human body and must be excreted through the hepatobiliary system. Accumulating scientific evidence suggests that administration of high doses of intravenous lipids that are high in phytosterols contributes to the development of parenteral nutrition-associated liver disease. In this review, mechanisms by which lipids and phytosterols may cause cholestasis are discussed. Human studies of the association of phytosterols with liver disease are reviewed. In addition, clinical studies of lipid/phytosterol reduction for reversing and/or preventing parenteral nutrition associated liver disease are discussed.

Modulation of endothelial cell integrity and inflammatory activation by commercial lipid emulsions.

BACKGROUND: Thrombosis and immune dysfunction are two important complications that result from the administration of parenteral nutrition. Endothelial cells within the vasculature are crucial components necessary for maintenance of normal coagulation and immune function. METHODS: We compared the effects of three commercial lipid emulsions (LEs; Intralipid®, ClinOleic® [or Clinolipid®], and Omegaven®) differing in the levels of omega-6 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, omega-9 monounsaturated fatty acids, and saturated fatty acids upon endothelial cell fatty acid composition using Gas chromatography, endothelial cell integrity by assessing measurement of apoptosis and necrosis using flow cytometry, endothelial cell inflammatory activation by assessing the induction of ICAM-1 by lipopolysaccharide [LPS]), and transcription factor activation (phosphorylation of NF-κB) using western blot analysis. RESULTS: Gas chromatographic analysis confirmed cellular uptake of the fatty acids within the LEs; furthermore, these fatty acid changes reflected the composition of the oils and egg phosphatides used in the manufacturing of these emulsions. However, the kinetics of fatty acid uptake and processing differed between LEs. Fish oil LE negatively impacted cell viability by doubling the percentage of apoptotic and necrotic cell populations quantified by flow cytometry using Annexin V/Fluorescein and propidium iodide. The soybean oil LE did not alter cell viability, while the olive oil-predominate emulsion improved cell viability. All LEs were capable of suppressing LPS-induced ICAM-1 expression; however, the fish oil LE was more potent than the other emulsions. Fish oil LE supplementation of cells also suppressed LPS-induced phosphorylation of NF-κB, while the soybean oil and olive predominant LE had no effect upon NF-κB phosphorylation. CONCLUSIONS: Lipid emulsions are readily incorporated and stored in the form of triacylglycerols. Soybean oil-based, olive oil-predominant and fish-oil based LEs differentially affected endothelial cell integrity. Importantly, these three LEs were capable of suppressing endothelial cell inflammatory response despite their fatty acid content.

Tocopherol and tocotrienol homologs in parenteral lipid emulsions.

Parenteral lipid emulsions, which are made of oils from plant and fish sources, contain different types of tocopherols and tocotrienols (vitamin E homologs). The amount and types of vitamin E homologs in various lipid emulsions vary considerably and are not completely known. The objective of this analysis was to develop a quantitative method to determine levels of all vitamin E homologs in various lipid emulsions. An HPLC system was used to measure vitamin E homologs using a Pinnacle DB Silica normal phase column and an isocratic, n-hexane:1,4 dioxane (98:2) mobile phase. An optimized protocol was used to report vitamin E homolog concentrations in soybean oil-based (Intralipid®, Ivelip®, Lipofundin® N, Liposyn® III, and Liposyn® II), medium- and long-chain fatty acid-based (Lipofundin®, MCT and Structolipid®), olive oil-based (ClinOleic®), and fish oil-based (Omegaven®) and mixture of these oils-based (SMOFlipid®, Lipidem®) commercial parenteral lipid emulsions. Total content of all vitamin E homologs varied greatly between different emulsions, ranging from 57.9 to 383.9 µg/mL. Tocopherols (α, ß, γ, δ) were the predominant vitamin E homologs for all emulsions, with tocotrienol content < 0.3%. In all of the soybean emulsions, except for Lipofundin® N, the predominant vitamin E homolog was γ-tocopherol, which ranged from 57-156 µg/mL. ClinOleic® predominantly contained α-tocopherol (32 µg/mL), whereas α-tocopherol content in Omegaven® was higher than most of the other lipid emulsions (230 µg/mL). PRACTICAL APPLICATIONS: The information on the types and quantity of vitamin E homologs in various lipid emulsions will be extremely useful to physicians and healthcare personnel in selecting appropriate lipid emulsions that are exclusively used in patients with inadequate gastrointestinal function, including hospitalized and critically ill patients. Some emulsions may require vitamin E supplementation in order to meet minimal human requirements.

Proceedings From FDA/A.S.P.E.N. Public Workshop: Clinical Trial Design for Intravenous Fat Emulsion Products, October 29, 2013.

The development of intravenous fat emulsion (IVFE) is the culmination of physiological, biochemical, nutritional, and medical scientific advancements. IVFEs have the ability to deliver critical nutritional substrates to the patient. Recent literature purports that they may also play roles in modulation of immune functionality and pulmonary physiology, but data supporting these potential benefits are limited. While soybean-based IVFEs have comprised the dominant fat in U.S. markets, a number of other novel IVFEs may prove to optimize the care of children and adults in both hospitalized and home settings. The October 2013 U.S. Food and Drug Administration (FDA)/American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) Public Workshop brought together scientists, researchers, and clinical experts to present updated clinical perspectives of IVFEs, including historical development, current state of usage throughout the world, and considerations for the regulatory approval of new IVFEs in the United States.

Parenteral lipid emulsions in guinea pigs differentially influence plasma and tissue levels of fatty acids, squalene, cholesterol, and phytosterols.

Lipid emulsions are made by mixing vegetable and/or fish oils with egg yolk and contain different types and amounts of fatty acids and sterols. This study assessed the effects of oral diet, soybean oil (SO)-, fish oil (FO)-, a mixture of olive and soybean oil (OOSO)-, and a mixture of fish, olive, coconut, and soybean oil (FOCS)-based emulsions on plasma triacylglycerols and plasma and tissue fatty acid and sterol content following acute and chronic intravenous administration in the guinea pig. Upon acute administration, peak triacylglycerols were highest with SO and lowest with OOSO. Upon chronic administration, the plasma triglyceride levels did not increase in any group over that of the controls. Fatty acid levels varied greatly between organs of animals on the control diets and organs of animals following acute or chronic lipid administration. Squalene levels increased in plasma following acute administration of OOSO, but plasma squalene levels were similar to control in all emulsion groups following chronic administration. Total plasma phytosterol levels were increased in the SO, OOSO, and FOCS groups following both acute and chronic infusions, whereas phytosterols were not increased following FO infusion. Total phytosterol levels were higher in liver, lung, kidney and adipose tissue following SO and OOSO. Levels were not increased in tissues after FO and FOCS infusion. These results indicate that fatty acid and sterol contents vary greatly among organs and that no one tissue reflects the fatty acid or sterol composition of other tissues, suggesting that different organs regulate these compounds differently.

A retrospective, observational study of patient outcomes for critically ill patients receiving parenteral nutrition.

OBJECTIVE: To evaluate health care-related utilization for critically ill patients receiving parenteral nutrition (PN) administered via a premixed multichamber bag (MCB) or compounded solutions (COM). DESIGN: A retrospective database analysis of critically ill patients (intensive care unit stay ≥ 3 days) receiving PN and discharged between January 1, 2010, and June 30, 2011, using the Premier Hospital Database. Patients were identified as receiving MCB or COM on the basis of product description codes. Primary outcomes were length of stay (LOS) and total costs. Comorbidities and clinical outcomes were identified using International Classificaion of Diseases, Ninth Revision diagnosis codes. All costs reported were for inpatient services only. Patients receiving MCB and COM were matched on key patient and hospital characteristics using a propensity score methodology. Multivariate regression models for cost and LOS used generalized linear models with a log link and gamma distribution. RESULTS: A total of 42,631 patients met the inclusion criteria (MCB = 5,679; COM = 36,952), and the final matched population included 3,559 patients from each cohort. Baseline patient and hospital characteristics were well matched between groups. Adjusted multivariate models demonstrated a small difference between groups for LOS (MCB = 9.40 days vs. COM = 9.65 days; P = 0.014). In addition, patients receiving MCB incurred approximately 9.1% less in total costs (MCB = $37,790 vs. COM = $41,569; P < 0.001). CONCLUSIONS: Overall, patients receiving MCB and COM experienced similar LOS, though patients receiving MCB had significantly lower overall costs. Interpretation of the study findings is subject to several limitations, and additional studies that include explicit identification of the method for compounding are needed.

Characteristics and current practice of parenteral nutrition in hospitalized patients.

BACKGROUND: For 40 years, parenteral nutrition (PN) has provided therapeutic benefits to patients unable to receive oral/enteral nutrition. Very limited published evidence exists to describe modern PN practices or characteristics of patients receiving PN. The aim of this article was to describe the characteristics of hospitalized patients receiving PN in 196 U.S. hospitals to define patient groups at risk for PN-related complications. This will provide researchers a baseline understanding about who is receiving hospital-based PN to maximize generalizability and validity of future research. METHODS: Claims data from the Premier Perspective database, the largest inpatient clinical database in the United States, were used to evaluate hospital-based PN practices. Data gathered between January 2005 and December 2007 included a total of 106,374 patients receiving PN. A total of 68,984 adults (age ≥ 18 years), 34,307 infants (age <1 year), and 3083 pediatric patients (age 1-17 years) were evaluated. Key variables such as admitting diagnosis, infection rates, in-hospital mortality, and costs were extracted. RESULTS: Hospitalized patients requiring PN in the United States are older and more often white than the overall hospitalized population. Hospitalized PN patients are more likely to be admitted emergently and have a higher severity of illness. Bloodstream infection rates in adult PN patients (25.5%) were considerably higher than in pediatric (14.7%) or neonatal patients (1.7%) receiving PN. CONCLUSIONS: These findings are the first large-scale description of "real-world" hospital-based PN practices in the United States, helping set a baseline for future PN research.

Steroidal compounds in commercial parenteral lipid emulsions.

Parenteral nutrition lipid emulsions made from various plant oils contain steroidal compounds, called phytosterols. During parenteral administration of lipid emulsions, phytosterols can reach levels in the blood that are many fold higher than during enteral administration. The elevated phytosterol levels have been associated with the development of liver dysfunction and the rare development of liver failure. There is limited information available in the literature related to phytosterol concentrations in lipid emulsions. The objective of the current study was to validate an assay for steroidal compounds found in lipid emulsions and to compare their concentrations in the most commonly used parenteral nutrition lipid emulsions: Liposyn(®) II, Liposyn(®) III, Lipofundin(®) MCT, Lipofundin(®) N, Structolipid(®), Intralipid(®), Ivelip(®) and ClinOleic(®). Our data demonstrates that concentrations of the various steroidal compounds varied greatly between the eight lipid emulsions, with the olive oil-based lipid emulsion containing the lowest levels of phytosterols and cholesterol, and the highest concentration of squalene. The clinical impression of greater incidences of liver dysfunction with soybean versus MCT/LCT and olive/soy lipid emulsions may be reflective of the levels of phytosterols in these emulsions. This information may help guide future studies and clinical care of patients with lipid emulsion-associated liver dysfunction.

Is there a difference in bloodstream infections in critically ill patients associated with ready-to-use versus compounded parenteral nutrition?

BACKGROUND & AIMS: Parenteral nutrition is widely used in critically ill patients receiving nutritional support. Several previous studies associated the use of parenteral nutrition with the development of bloodstream infections. This study compared bloodstream infections in critical care patients receiving parenteral nutrition (PN) prepared via conventional compounding versus premixed multichamber bags. METHODS: Records in the Premier Perspective™ database for all in patients ≥ 18 years of age, with a minimum 3-day intensive care unit stay, who received PN between 2005 and 2007 were analyzed (n = 15,328). Statistical analysis of data, grouped according to preparation method, compared differences in both observed bloodstream infection rates and adjusted rates, using logistic regression to examine the impact of hospital and patient baseline characteristics. RESULTS: Patients receiving compounded parenteral nutrition had longer intensive care unit stays (11.3 vs. 9.1 days) and longer hospital stays (22.6 vs. 19.4 days); both P < .001. After adjusting for baseline differences, the probability for bloodstream infections was 19% higher when using compounded parenteral nutrition vs. multichamber bags (29.6 vs. 24.9%; odd ratio = 1.29; 95% confidence interval = 1.06-1.59). CONCLUSION: In this retrospective review of a large patient database the adjusted probability of bloodstream infection was significantly lower in patients receiving multichamber bags than compounded parenteral nutrition. These findings need to be investigated further in high quality observational studies and prospective clinical trials.

The ratio of energy expenditure to nitrogen loss in diverse patient groups--a systematic review.

BACKGROUND & AIMS: The ratio of energy expenditure to nitrogen loss respectively of energy to nitrogen provision (E/N) is considered a valuable tool in the creation of an enteral or parenteral formulation. Specific E/N ratios for parenteral nutrition (PN) have not yet been clearly defined. To determine the range of energy expenditure, nitrogen (protein) losses, and E/N ratios for various patient groups, we performed a systematic review of the literature. METHODS: Medline 1950-2011 was searched for all studies on patients or healthy controls reporting energy expenditure and nitrogen loss at the same time. RESULTS: We identified 53 studies with 91 cohorts which comprised 1107 subjects. Mean TEE ± standard deviation (SD) was 31.2 ± 7.2 kcal/kg BW/day in patients (n = 881) and 35.6 ± 4.3 kcal/kg BW/day in healthy controls (n = 266). Mean total protein loss (TPL) was 1.50 ± 0.57 g/kg BW/day in patients and 0.94 ± 0.24 g/kg BW/day in healthy controls. A non-linear significant correlation was found between TPL and the E/N ratio. CONCLUSION: The E/N ratio is not a constant value but decreases continuously with increasing protein loss. These variations should be considered in the nutritional support of patients.

Bloodstream infections in patients receiving manufactured parenteral nutrition with vs without lipids: is the use of lipids really deleterious?

BACKGROUND: This study compared overall bacterial and bloodstream infection rates in patients receiving premixed parenteral nutrition (PN) with vs without lipid emulsion. METHODS: Data from hospitalized patients who were ≥18 years of age and receiving premixed PN between 2005 and 2007 were extracted from the Premier Perspective database. Data were categorized into 2 groups: patients who received premixed PN only and those receiving premixed PN with lipids. Multiple logistic regression was used to adjust for risk factors and potential confounders, reporting the probability of risk for an infection. RESULTS: The group without lipids was observed to have lower rates of both overall bacterial infection (43.5% vs 53.5%) and bloodstream infection (14.5% vs 18.9%). However, after adjusting for baseline characteristics, there were no significant differences in overall risk of bacterial infections (51.4% vs 53.5%; odds ratio [OR] = 1.11; 95% confidence interval [CI], 0.96-1.27) or bloodstream infections (19.6% vs 19.2%; 0.97; 0.81-1.16). In a subset of patients in the intensive care unit for ≥3 days, lower overall bacterial infection rates (58.3% vs 67.3%) and bloodstream infection rates (31.0% vs 37.0%) were observed in the group without lipids. After adjustment, there were no significant differences in risk of overall bacterial infection (OR = 0.95; 95% CI, 0.75-1.22) or bloodstream infection (0.92; 0.71-1.19) between the 2 groups. CONCLUSIONS: When administered with premixed PN, lipid emulsion was not significantly associated with an increase in the risk of infectious morbidity when compared to omitting lipids from therapy.

Oleic acid inhibits stearic acid-induced inhibition of cell growth and pro-inflammatory responses in human aortic endothelial cells.

Saturated fatty acids (SFAs), significant components of both enteral/parenteral nutritional formulations (including diet), are linked to cardiovascular disease complications, such as atherosclerosis. We investigated whether oleic acid (C18:1n-9) reduces the growth inhibitory and pro-inflammatory effects of the stearic acid (C18:0) in human aortic endothelial cells (HAEC). Stearic acid induced growth inhibition at concentrations less than 50 µM, whereas higher concentrations invoked cytotoxicity. Stearic acid-induced growth inhibition and cytotoxic effects were eradicated upon cosupplementation with oleic acid (25 µM). Oleic acid (as low as 5 µM) also inhibited the stearic acid-induced increase in intercellular adhesion molecule-1 (ICAM-1) expression. Stearic acid-induced phosphorylation of nuclear factor-kappa B (NF-κB), a transcriptional regulator of ICAM-1, was also reduced by oleic acid. HAECs supplemented with either stearic or oleic acid resulted in cellular incorporation of C18:0 and C18:1n-9, respectively. Stearic acid primarily incorporated into phospholipids without increasing the total fatty acid content in HAECs. In contrast, oleic acid, with or without stearic acid, incorporated into both phospholipids and triglycerides, with a significant increase in total fatty acid amounts in triglycerides. Our data suggest that oleic acid has the ability to reduce the inflammatory effects of long-chain SFAs in HAECs through reducing cellular stearic acid incorporation and NF-κB activation.