Use of fish oil in parenteral nutrition: Rationale and reality

Omega-3 polyunsaturated fatty acids ameliorate PM2.5 exposure induced lung injury in mice through remodeling the gut microbiota and modulating the lung metabolism

Short-term or long-term exposure to fine particulate matter (PM2.5) is related to increased incidences of respiratory diseases. This study aimed to investigate the influences of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) supplementation on oxidative stress, inflammation, lung metabolic profile, and gut microbiota in PM2.5-induced lung injury mice. Mice were divided into four groups (n = 15, per group): two unsupplemented groups, control group and PM2.5 group, and two supplemented groups with ω-3 PUFAs, ω-3 PUFAs group, and ω-3 PUFAs + PM2.5 group. Mice in the supplemented groups were placed on an ω-3 PUFAs-enriched diet (ω-3 PUFAs, 21 g/kg). During the 5th to 6th week of dietary supplementation, mice were exposed to PM2.5 by intra-tracheal instillation. ω-3 PUFAs ameliorate lung histopathological injury, reduce inflammatory responses and oxidative stress, affect lung metabolite profile, and modulate gut microbiota in PM2.5-induced lung injury mice. Thus, supplementary ω-3 PUFAs showed effectiveness in attenuation of PM2.5-induced lung injury, indicating that the interventions exhibited preventive and therapeutic potential.

Clinical and neurodevelopmental outcomes in premature infants exposed to intravenous fish- and soybean oil-based lipid emulsions

BACKGROUND

The optimal composition of lipid emulsions in parenteral nutrition (PN) for premature infants remains controversial. This study examined the effects of a combination of soybean oil-based (SoyLE) and fish oil-based (FishLE) lipid emulsions compared to FishLE as monotherapy on the lipid and fatty acid profiles and clinical outcomes of premature infants requiring prolonged PN.

METHODS

42 premature infants received FishLE+SoyLE or FishLE. Serum concentrations of lipoproteins and 29 fatty acids (FA) were measured at baseline, 4, and 8 weeks of PN and growth and neurodevelopmental outcomes were measured at 3, 6, 12, 18, and 24 months of life.

RESULTS

Lipid profiles were similar between groups. Plasma concentrations of ω-6 fatty acids tended to decrease over time in both groups. Concentrations of most ω-3 fatty acids, in particular docosapentaenoic acid, eicosapentaenoic acid, and docosahexaenoic acid, were significantly increased over time in the FishLE+SoyLE group whereas they did not change in the FishLE alone group. However, serum concentrations of almost all fatty acids were similar between groups at the end of the study period. No differences in growth parameters including weight, height, fronto-occipital circumference (FOC), and body mass index (BMI) were observed up to two years of age. Similarly, there were no differences in neurodevelopmental test scores at 6, 12, 18, and 24 months of age.

CONCLUSIONS

No substantial differences in lipid profiles and short clinical outcomes were found in infants exposed to FishLE+SoyLE when compared to FishLE.

Erythrocyte fatty acid membrane composition in children on long-term parenteral nutrition enriched with ω-3 fatty acids

BACKGROUND

Composite lipid emulsions containing soybean oil (30%), medium-chain triglycerides (30%), olive oil (25%), and fish oil (15%) (SMOF) are now widely used.

OBJECTIVES

We aimed to evaluate the tolerance, the efficiency, and the erythrocyte fatty acid (FA) profile for children on long-term home parenteral nutrition (HPN) receiving a composite fish oil-based emulsion (FOLE).

METHODS

At baseline, children (n = 46) with severe intestinal failure highly dependent on parenteral nutrition (PN) for ≥1 y were included in the study when they had received the composite FOLE for >6 mo. Out of this baseline group, only 25 children remained highly PN-dependent (SMOF1, n = 25) and could be assessed a second time, 2.4 y later (SMOF2, n = 25). An independent control group ("weaned off PN" group; n = 24) included children who had been weaned off PN for >2 y (median: 4 y). RBC-FA composition was established by GC-MS. Growth parameters, plasma citrulline, conjugated bilirubin, FA profiles, and the Holman ratio (20:3ω-9/20:4ω-6) were compared between groups.

RESULTS

No difference for growth parameters, citrulline, and bilirubin was observed between the SMOF groups after 2.4 y (0.2 < P < 0.8). The weaned-off group did not differ from the SMOF groups for growth parameters (0.2 < P < 0.4) but citrulline was higher (P < 0.0001) and conjugated bilirubin lower (P < 0.01). The composite FOLE induced higher proportions of EPA (20:5n-3) (8.4% ± 2.9%) and DHA (22:6n-3) (11.7% ± 2.2%) than what was observed in weaned-off children (0.8% ± 0.4% and 6.6% ± 2.3%, respectively) but lower proportions of arachidonic acid (20:4n-6). However, the Holman ratio did not vary between groups (P = 0.9), whereas the PUFA concentrations varied widely.

CONCLUSIONS

Long-term use of the composite FOLE was well tolerated in HPN-dependent children. The RBC-FA profile alterations were consistent with the ω-3 PUFA-enriched composition of this emulsion without evidence of essential FA deficiency.

Lipids in Parenteral Nutrition: Biological Aspects

Lipid emulsions are an integral part of parenteral nutrition, and traditionally have been regarded as an energy-dense source of calories and essential fatty acids. For many years, lipids used in parenteral nutrition have been based on vegetable oils (eg, soybean-oil emulsions). However, soybean-oil emulsions may not have an optimal fatty-acid composition under some circumstances when used as the only lipid source, as soybean oil is particularly abundant in the ω-6 polyunsaturated fatty acid (PUFA), linoleic acid. Hence, a progressive series of more complex lipid emulsions have been introduced, typically combining soybean oil with 1 or more alternative oils, such as medium-chain triglycerides (MCTs) and/or olive oil and/or fish oil. The wide range of lipid emulsions now available for parenteral nutrition offers opportunities to alter the supply of different fatty acids, which potentially modifies functional properties, with effects on inflammatory processes, immune response, and hepatic metabolism. Fish oil has become an important component of modern, composite lipid emulsions, in part owing to a growing evidence base concerning its biological effects in a variety of preclinical models. These biological activities of fish oil are mainly attributed to its ω-3 PUFA content, particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). DHA and EPA have known mechanisms of action, anti-inflammatory, immunomodulatory, and antioxidative properties. Specialized proresolving mediators, such as resolvins, protectins, and maresins, are synthesized directly from DHA and EPA, are key for the resolution of inflammation, and improve outcomes in many cell- and animal-based models and, recently, in some clinical settings.

Use of Lipids in Neonates Requiring Parenteral Nutrition

Neonates have limited antioxidative capacity and are at increased risk of infection and inflammation-a situation that is exacerbated in preterm neonates. Together, oxidative stress and inflammation are implicated in many serious conditions affecting neonates, such as bronchopulmonary dysplasia and periventricular leukomalacia. Neonates requiring parenteral nutrition have certain nutritional requirements. For example, very long-chain ω-3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are regarded as conditionally essential with critical roles during early retinal and brain development, and may also have other benefits such as anti-inflammatory effects. Because of these factors, the choice of lipid emulsion used as part of parenteral nutrition support may influence clinical outcomes in neonates. There are concerns that lipid emulsions based purely on soybean oil may increase lipid peroxidation, oxidative stress, and inflammation because of their high ω-6 PUFA and low ω-3 PUFA concentrations. Composite fish-oil containing lipid emulsions may provide advantages for neonates owing to their high DHA and EPA content and high antioxidant (α-tocopherol) levels. Here, we discuss clinical trials of lipid emulsions in preterm and term neonatal populations, with a particular emphasis on markers of oxidative stress and DHA and EPA levels. Olive oil/soybean oil lipid emulsions have shown few advantages in neonates over other lipid emulsions. However, compared with either pure soybean or soybean/olive-oil based emulsions, composite fish-oil containing lipid emulsions reduce oxidative stress/lipid peroxidation and also increase DHA and EPA levels. These advantages may translate into clinical benefits for neonates requiring parenteral nutrition.

Summary of Proceedings and Expert Consensus Statements From the International Summit "Lipids in Parenteral Nutrition"

BACKGROUND

The 2018 Lipids in Parenteral Nutrition summit involved a panel of experts in clinical nutrition, lipid metabolism, and pharmacology, to assess the current state of knowledge and develop expert consensus statements regarding the use of intravenous lipid emulsions in various patient populations and clinical settings. The main purpose of the consensus statements is to assist healthcare professionals by providing practical guidance on common clinical questions related to the provision of lipid emulsions as part of parenteral nutrition (PN).

METHODS

The summit was designed to allow interactive discussion and consensus development. The resulting consensus statements represent the collective opinion of the members of the expert panel, which was informed and supported by scientific evidence and clinical experience.

RESULTS

The current article summarizes the key discussion topics from the summit and provides a set of consensus statements designed to complement existing evidence-based guidelines. Lipid emulsions are a major component of PN, serving as a condensed source of energy and essential fatty acids. In addition, lipids modulate a variety of biologic functions, including inflammatory and immune responses, coagulation, and cell signaling. A growing body of evidence suggests that lipid emulsions containing ω-3 fatty acids from fish oil confer important clinical benefits via suppression of inflammatory mediators and activation of pathways involved in the resolution of inflammation.

CONCLUSIONS

This article provides a set of expert consensus statements to complement formal PN guideline recommendations.

Comparative study of the safety and efficacy of SMOFlipid vs non SMOFlipid as TPN for liver transplantation

Background

Liver transplantation (LT) is one of the widely recognised and leading treatments for end-stage liver disease. Nutrition impacts its success. Total parenteral nutrition (TPN) is usually prescribed for patients recommended prolonged fasting after LT. The supplement of SMOFlipid (soybean oil, MCT oil, olive oil, and fish oil) is easily metabolised to produce energy, and it possesses anti-inflammatory effects; however, SMOFlipid emulsion use raises concerns regarding coagulopathy after LT. This study investigated the postoperative correlation between SMOFlipid and coagulation in LT.

Materials and methods

The medical records of 54 recipients of living donor LT between January 2012 and June 2015 were retrospectively reviewed. Patients with pretransplant platelet count <40,000/μL and >40,000/μL were assigned to the non-SMOFlipid (n = 23) group and the SMOFlipid (n = 31) group, respectively.

Results

The coagulation and nutrition profile of patients improved significantly after TPN support. No significant difference was observed in the coagulation profile between SMOFlipid and non-SMOFlipid groups. Although the SMOFlipid group exhibited a higher platelet count than the non-SMOFlipid group on day 7 (P < 0.001), no significant differences were observed in the platelet count on 14 and 30 days after TPN support between the 2 groups.

Conclusion

TPN using SMOFlipid after LT is a good strategy for improving nutritional status without increasing the risks of bleeding and coagulation in patients intolerant of early enteral nutrition. Moreover, SMOFlipid use may not cause coagulopathy up to 14 days after LT. Overall, SMOFlipid provides nutritional benefits without increasing the risk of bleeding.

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TPN usually prescribed for nutrition support at early stage after liver transplantation is important.

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SMOFlipid emulsion supplement in TPN improves nutritional status during early post-LT period within 14 days.

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TPN support with SMOFlipid emulsion does not impair coagulation parameters nor increase the risk of thrombocytopenia.

ω-3 Fatty-Acid Enriched Parenteral Nutrition in Hospitalized Patients: Systematic Review With Meta-Analysis and Trial Sequential Analysis

This systematic review and meta-analysis investigated ω-3 fatty-acid enriched parenteral nutrition (PN) vs standard (non-ω-3 fatty-acid enriched) PN in adult hospitalized patients (PROSPERO 2018 CRD42018110179). We included 49 randomized controlled trials (RCTs) with intervention and control groups given ω-3 fatty acids and standard lipid emulsions, respectively, as part of PN covering ≥70% energy provision. The relative risk (RR) of infection (primary outcome; 24 RCTs) was 40% lower with ω-3 fatty-acid enriched PN than standard PN (RR 0.60, 95% confidence interval [CI] 0.49-0.72; P < 0.00001). Patients given ω-3 fatty-acid enriched PN had reduced mean length of intensive care unit (ICU) stay (10 RCTs; 1.95 days, 95% CI 0.42-3.49; P = 0.01) and reduced length of hospital stay (26 RCTs; 2.14 days, 95% CI 1.36-2.93; P < 0.00001). Risk of sepsis (9 RCTs) was reduced by 56% in those given ω-3 fatty-acid enriched PN (RR 0.44, 95% CI 0.28-0.70; P = 0.0004). Mortality rate (co-primary outcome; 20 RCTs) showed a nonsignificant 16% reduction (RR 0.84, 95% CI 0.65-1.07; P = 0.15) for the ω-3 fatty-acid enriched group. In summary, ω-3 fatty-acid enriched PN is beneficial, reducing risk of infection and sepsis by 40% and 56%, respectively, and length of both ICU and hospital stay by about 2 days. Provision of ω-3-enriched lipid emulsions should be preferred over standard lipid emulsions in patients with an indication for PN.

Short bowel syndrome in children and adults: from rehabilitation to transplantation

Short bowel syndrome (SBS) is a dramatic clinical condition in both children and adults; the residual bowel length is not sufficient to avoid intestinal failure, with subsequent malnutrition and growth retardation, and intravenous support is required to provide the nutrients normally coming from the intestine. Apart from the primary disease, the medical status can be worsened by complications of intestinal failure: if there are irreversible, the prognosis is poor unless a successful intestinal rehabilitation is achieved. Areas covered: The rescue of the remnant small bowel requires a multidisciplinary expertise to achieve digestive autonomy. The use of intestinal trophic factors has shown encouraging results in improving the intestinal adaptation process. Whenever the residual bowel length is inadequate, in a well-selected population weaning parenteral nutrition (PN) off could be attempted by surgery through lengthening procedures. A further subset of patients, with total and irreversible intestinal failure and severe complications on PN, may have an indication to intestinal transplantation. This procedure is still affected by poor long-term results. Expert commentary: Novel approaches developed through a multidisciplinary team work, such as manipulation of microbiota or tissue bioengineering, should be added to current therapies to treat successfully SBS.

Fish Oil-Containing Lipid Emulsions in Adult Parenteral Nutrition: A Review of the Evidence

BACKGROUND

There is evidence from laboratory and animal studies that fish oil-containing intravenous lipid emulsions (FOC-IVLEs) have a beneficial effect on inflammation and the immune response, suggesting a possible clinical benefit. Clinical studies of FOC-IVLEs have reported mixed results. The aim of this review is to present findings from recent randomized controlled clinical trials and other quality clinical studies investigating the effects of administering intravenous fish oil alone or as part of a multilipid emulsion and to examine the quality of these studies in an objective, evidence-based manner.

METHODS

Studies comparing FOC-IVLEs with other IVLEs in adults were included. Thirty-four clinical studies were evaluated: 19 investigated levels of inflammatory and immune markers as an endpoint; 13 investigated rates of infection or sepsis; 3 investigated clinical outcomes in septic patients; and 29 investigated general clinical outcomes.

RESULTS

There was conflicting evidence for a beneficial effect of fish oil on levels of inflammatory and immune markers and some evidence that fish oil decreased the rate of postoperative atrial fibrillation. Studies generally reported few statistical differences in clinical outcomes and rates of infection and sepsis with FOC-IVLEs as compared with other IVLEs. The quality of reporting was generally poor, and the presented evidence for comparisons between FOC-IVLEs and other IVLEs was inconclusive or weak.

CONCLUSIONS

There is very little high-quality evidence that FOC-IVLEs have a more beneficial effect than other IVLEs on clinical outcomes in adult patients.

Krill Oil-In-Water Emulsion Protects against Lipopolysaccharide-Induced Proinflammatory Activation of Macrophages In Vitro

Background: Parenteral nutrition is often a mandatory therapeutic strategy for cases of septicemia. Likewise, therapeutic application of anti-oxidants, anti-inflammatory therapy, and endotoxin lowering, by removal or inactivation, might be beneficial to ameliorate the systemic inflammatory response during the acute phases of critical illness. Concerning anti-inflammatory properties in this setting, omega-3 fatty acids of marine origin have been frequently described. This study investigated the anti-inflammatory and LPS-inactivating properties of krill oil (KO)-in-water emulsion in human macrophages in vitro. Materials and Methods: Differentiated THP-1 macrophages were activated using specific ultrapure-LPS that binds only on the toll-like receptor 4 (TLR4) in order to determine the inhibitory properties of the KO emulsion on the LPS-binding capacity, and the subsequent release of TNF-α. Results: KO emulsion inhibited the macrophage binding of LPS to the TLR4 by 50% (at 12.5 µg/mL) and 75% (at 25 µg/mL), whereas, at 50 µg/mL, completely abolished the LPS binding. Moreover, KO (12.5 µg/mL, 25 µg/mL, or 50 µg/mL) also inhibited (30%, 40%, or 75%, respectively) the TNF-α release after activation with 0.01 µg/mL LPS in comparison with LPS treatment alone. Conclusion: KO emulsion influences the LPS-induced pro-inflammatory activation of macrophages, possibly due to inactivation of the LPS binding capacity.

Omega-3 Fatty Acids in Modern Parenteral Nutrition: A Review of the Current Evidence

Intravenous lipid emulsions are an essential component of parenteral nutrition regimens. Originally employed as an efficient non-glucose energy source to reduce the adverse effects of high glucose intake and provide essential fatty acids, lipid emulsions have assumed a larger therapeutic role due to research demonstrating the effects of omega-3 and omega-6 polyunsaturated fatty acids (PUFA) on key metabolic functions, including inflammatory and immune response, coagulation, and cell signaling. Indeed, emerging evidence suggests that the effects of omega-3 PUFA on inflammation and immune response result in meaningful therapeutic benefits in surgical, cancer, and critically ill patients as well as patients requiring long-term parenteral nutrition. The present review provides an overview of the mechanisms of action through which omega-3 and omega-6 PUFA modulate the immune-inflammatory response and summarizes the current body of evidence regarding the clinical and pharmacoeconomic benefits of intravenous n-3 fatty acid-containing lipid emulsions in patients requiring parenteral nutrition.

Differential Impacts of Soybean and Fish Oils on Hepatocyte Lipid Droplet Accumulation and Endoplasmic Reticulum Stress in Primary Rabbit Hepatocytes

Parenteral nutrition-associated liver disease (PNALD) is a severe ailment associated with long-term parenteral nutrition. Soybean oil-based lipid emulsions (SOLE) are thought to promote PNALD development, whereas fish oil-based lipid emulsions (FOLE) are thought to protect against PNALD. This study aimed to investigate the effects of SOLE and FOLE on primary rabbit hepatocytes. The results reveal that SOLE caused significant endoplasmic reticulum (ER) and mitochondrial damage, ultimately resulting in lipid droplets accumulation and ER stress. While these deleterious events induce hepatocyte injury, FOLE at high doses cause only minor ER and mitochondrial damage, which has no effect on hepatic function. SOLE also significantly upregulated glucose-regulated protein 94 mRNA and protein expression. These data indicate that SOLE, but not FOLE, damage the ER and mitochondria, resulting in lipid droplets accumulation and ER stress and, finally, hepatocyte injury. This likely contributes to the differential impacts of SOLE and FOLE on PNALD development and progression.

Safety and efficacy of parenteral fish oil-containing lipid emulsions in premature neonates

OBJECTIVE

The aim of the study was to evaluate the safety and efficacy of fish oil-containing (FO) lipid emulsions that are rich in ω-3 fatty acids for parenteral nutrition in preterm neonates by using data retrieved from randomized controlled trials.

METHODS

We performed a meta-analysis of 8 randomized controlled trials representing 483 premature neonates to compare FO with control (CO) lipid emulsions.

RESULTS

This meta-analysis revealed that the levels of ω-3 fatty acids in the form of docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid (% of total fatty acids) in plasma were statistically higher in FO groups (mean difference [MD] -0.7%, 95% confidence interval [CI] -1.05 to -0.36, P < 0.001; MD -1.31%, 95% CI -1.40 to -1.21, P < 0.001). The differences were found in red blood cell (RBC) membranes. The levels of arachidonic acid (% of total fatty acids) as ω-6 fatty acid in plasma and red blood cell membranes were significantly lower in FO groups (MD 1.27%, 95% CI 1.12-1.42, P < 0.001) (MD 0.92%, 95% CI 0.12-1.72, P = 0.02). The mean body weight, serum level of bilirubin, triglycerides or C-reactive protein, all-cause mortality, and rate of lipid emulsion-associated complications were, however, not different between FO and CO groups.

CONCLUSIONS

The level of docosahexaenoic acid is efficiently improved by FO lipid emulsions. The changes observed in eicosapentaenoic acid and arachidonic acid, and the associated safety issue, however, remain to be clarified. Any clinical benefit or detrimental effect of using FO in premature neonates cannot be demonstrated by the present study.

A randomized controlled trial investigating the effects of parenteral fish oil on survival outcomes in critically ill patients with sepsis: a pilot study

INTRODUCTION

Death from sepsis in the intensive care unit (ITU) is frequently preceded by the development of multiple organ failure as a result of uncontrolled inflammation. Treatment with ω-3 has been demonstrated to attenuate the effects of uncontrolled inflammation and may be clinically beneficial.

METHOD

A randomized control trial investigating the effects of parenteral ω-3 was carried out. Consecutive patients diagnosed with sepsis were entered into the study and randomized to receive either parenteral ω-3 or standard medical care only. The primary outcome measure was a reduction in organ dysfunction using the Sequential Organ Failure Assessment (SOFA) score as a surrogate marker. The secondary outcome measures were mortality, length of stay, mean C-reactive protein (CRP), and days free of organ dysfunction/failure.

RESULTS

Sixty patients were included in the study. The baseline demographics were matched for the two cohorts. Patients treated with parenteral ω-3 were associated with a significant reduction in new organ dysfunction (Δ-SOFA 2.2 ± 2.2 vs. 1.0 ± 1.5, P = .005 and maximum-SOFA 10.1 ± 4.2 vs. 8.1 ± 3.2, P = .041) and maximum CRP (186.7 ± 78 vs. 141.5 ± 62.6, P = .019). There was no significant reduction in the length of stay between cohorts. Patients treated with ω-3 in the strata of less severe sepsis had a significant reduction in mortality (P = .042).

CONCLUSION

The treatment of critically ill septic patients with parenteral ω-3 is safe. It is associated with a significant reduction in organ dysfunction. It may be associated with a reduction in mortality in patients with less severe sepsis.

Randomized clinical trial of new intravenous lipid (SMOFlipid 20%) versus medium-chain triglycerides/long-chain triglycerides in adult patients undergoing gastrointestinal surgery

BACKGROUND

SMOFlipid 20% is intravenous lipid emulsion (ILE) containing long-chain triglycerides (LCT), medium-chain triglycerides (MCT), olive oil, and fish oil as a mixed emulsion containing α-tocopherol. The aim was to assess the efficacy of this new ILE in gastrointestinal surgery compared with MCT/LCT.

METHODS

In this prospective study, 40 patients were randomized to SMOFlipid 20% or MCT/LCT (Lipovenoes 20%) group. Clinical and biochemistry data were collected. Inflammatory markers (CRP, IL-6, IL-10, TNF-α, TGF-β1) and oxidative stress (ROS and superoxide) were measured.

RESULTS

Thirty-five patients (17 males and 18 females) with a mean age of 57 years completed the study. The patients' demographic characteristics (age, gender, height, body weight, and BMI) were similar without significant differences between groups. The increment of triglyceride on day 6 from baseline was significantly lower in SMOFlipid group than in Lipovenoes MCT/LCT group. Inflammatory markers, as well as superoxide radical and total oxygen radical were not different between groups.

CONCLUSIONS

Despite the comparable effect on inflammatory response, because of its well-balanced fatty acid pattern, relatively low n-6:n-3 ratio, and high vitamin E content, SMOFlipid had a better triglyceride-lowering effect as compared with MCT/LCT in adult patients undergoing gastrointestinal surgery.

Randomized clinical trial of perioperative omega-3 fatty acid supplements in elective colorectal cancer surgery

BACKGROUND

Omega-3 fatty acids (n-3 FAs) may have beneficial clinical effects, and n-3 FA supplements may improve outcome after surgery.

METHODS

In a randomized double-blind placebo-controlled trial in single centre, patients referred for elective colorectal cancer surgery received either an n-3 FA-enriched oral nutritional supplement (ONS) (Supportan, 200 ml twice daily) providing 2.0 g eicosapentaenoic acid (EPA) and 1.0 g docosahexaenoic acid (DHA) per day, or a standard isocaloric and isonitrogenous ONS, for 7 days before and 7 days after surgery. The primary endpoint was infectious and non-infectious complications within 30 days of surgery. Secondary endpoints were length of hospital stay, intensive care unit admission, readmissions, and concentrations of marine n-3 FAs and arachidonic acid in granulocyte membranes.

RESULTS

Some 148 consecutive patients (68 women, 80 men; mean age 71 (range 41-89) years) were randomized. There was no significant difference between groups in infectious or non-infectious postoperative complications (P = 1.000). Granulocyte levels of EPA, DHA and docosapentaenoic acid (DPA) were significantly higher in the n-3 FA-enriched supplement group compared with the control group (P < 0.001). The arachidonic acid level in granulocytes was significantly lower in the enriched group than in the control group (P < 0.001).

CONCLUSION

EPA, DHA and DPA were incorporated into granulocytes in patients receiving n-3 FAs, but this was not associated with improved postoperative outcomes.

REGISTRATION NUMBER

NCT00488904 (http://www.clinicaltrials.gov).

Lipids for intravenous nutrition in hospitalised adult patients: a multiple choice of options

Lipids used in parenteral nutrition provide energy, building blocks and essential fatty acids. Traditionally, these lipids have been based on n-6 PUFA-rich vegetable oils particularly soyabean oil. This may not be optimal because soyabean oil may present an excessive supply of linoleic acid. Alternatives to use of soyabean oil include its partial replacement by medium-chain TAG, olive oil or fish oil, either alone or in combination. Lipid emulsions containing these alternatives are well tolerated without adverse effects in a wide range of hospitalised adult patients. Lipid emulsions that include fish oil have been used in parenteral nutrition in adult patients' post-surgery (mainly gastrointestinal). This has been associated with alterations in patterns of inflammatory mediators and in immune function and, in some studies, a reduction in length of intensive care unit and hospital stay. These benefits are emphasised through recent meta-analyses. Perioperative administration of fish oil may be superior to post-operative administration. Parenteral fish oil has been used in critically ill adults. Here, the influence on inflammatory processes, immune function and clinical endpoints is not clear, since there are too few studies and those that are available report contradictory findings. However, some studies found reduced inflammation, improved gas exchange and shorter length of hospital stay in critically ill patients if they receive fish oil. More and better trials are needed in patient groups in which parenteral nutrition is used and where fish oil may offer benefits.

Resolution of parenteral nutrition-associated jaundice on changing from a soybean oil emulsion to a complex mixed-lipid emulsion

BACKGROUND AND OBJECTIVE

Resolution of parenteral nutrition (PN)-associated jaundice has been reported in children given a reduced dose of intravenous fat using a fish oil-derived lipid emulsion. The aim of the present study was to examine the effect on PN-associated jaundice of changing from a soybean oil-derived lipid to a mixed lipid emulsion derived from soybean, coconut, olive, and fish oils without reducing the total amount of lipid given.

METHODS

Retrospective cohort comparison examining serum bilirubin during 6 months in children with PN-associated jaundice who changed to SMOFlipid (n=8) or remained on Intralipid (n=9).

RESULTS

At entry, both groups received most of their energy as PN (SMOFlipid 81.5%, range 65.5-100 vs Intralipid 92.2%, range 60.3-100; P=0.37). After 6 months, both tolerated increased enteral feeding but still received large proportions of their energy as PN (SMOFlipid 68.4%, range 36.6-100 vs Intralipid 50%, range 37.6-76; P=0.15). The median bilirubin at the outset was 143 μmol/L (range 71-275) in the SMOFlipid group and 91 μmol/L (range 78-176) in the Intralipid group. After 6 months, 5 of 8 children in the SMOFlipid and 2 of 9 children in the Intralipid group had total resolution of jaundice. The median bilirubin fell by 99 μmol/L in the SMOFlipid group but increased by 79 μmol/L in the Intralipid group (P=0.02).

CONCLUSIONS

SMOFlipid may have important protective properties for the liver and may constitute a significant advance in PN formulation. Randomised trials are needed to study the efficacy of SMOFlipid in preventing PN liver disease.

Can enhanced recovery programmes be further improved by the addition of omega three fatty acids?

AIMS

The term "enhanced recovery programme (ERP)" means applying defined protocols to augment the recovery of patients following surgery. Inflammation is body's response to insults such as infection, injury and surgical procedures. Inflammatory mediators whose function is initially protective may cause undesirable consequences, if the response is unnecessarily prolonged. The principle effects of ERP result from the reduction of the profound stress which results following major surgical procedures.

METHODS

A Pubmed literature search was undertaken using the keywords enhanced recovery, surgery and omega-3. The primary endpoint was whether the addition of omega-3 to ERP improved morbidity and mortality.

RESULTS

Nine randomised trials examining the effect of omega-3 enriched diets following surgery were analysed. Inclusion of omega-3 helps in maintaining a positive nitrogen balance, overcome immune dysfunction, lower the incidence of post-operative infections with the consequence of reduced morbidity and mortality.

CONCLUSIONS

The provision of early or continuous nutrition is one of the cornerstones of an ERP. A theoretically ideal regimen would provide an energy substrate and protein and contain a component which would limit inappropriate inflammation. The beneficial role of omega-3 results from a number of effects which limit the inflammatory response, principally by influencing the production of eicosanoids and modulating cytokines. They also enhance cell-mediated immunity and preserve immune function better than standard dietary formulations. Although ERPs have already produced significant progress, there is sufficient evidence to suggest that the provision of omega-3 fatty acids may result in further improvements.

Improved outcome in neonatal short bowel syndrome using parenteral fish oil in combination with ω-6/9 lipid emulsions

BACKGROUND

Newborn infants with short bowel syndrome (SBS) represent a high-risk group of developing intestinal failure-associated liver disease (IFALD), which may be fatal. However, infants have a great capacity for intestinal growth and adaptation if IFALD can be prevented or reversed. A major contributing factor to IFALD may be the soybean oil-based intravenous lipid emulsions used since the introduction of parenteral nutrition (PN) 40 years ago.

METHODS

This retrospective study compares the outcome in 20 neonates with SBS treated with parenteral fish oil (Omegaven) in combination with ω-6/9 lipid emulsions (ClinOleic) with the outcome in a historical cohort of 18 patients with SBS who received a soybean oil-based intravenous lipid emulsion (Intralipid).

RESULTS

Median gestational age was 26 weeks in the treatment group and 35.5 weeks in the historical group. All patients were started on PN containing Intralipid that was switched to ClinOleic/Omegaven in the treatment group at a median age of 39 gestational weeks. In the treatment group, direct bilirubin levels were reversed in all 14 survivors with cholestasis (direct bilirubin >50 umol/L). Median time to reversal was 2.9 months. Only 2 patients died of liver failure (10%). In the historical cohort, 6 patients (33%) died of liver failure, and only 2 patients showed normalization of bilirubin levels.

CONCLUSIONS

Parenteral fish oil in combination with ω-6/9 lipid emulsions was associated with improved outcome in premature neonates with SBS. When used instead of traditional soybean-based emulsions, this mixed lipid emulsion may facilitate intestinal adaptation by increasing the IFALD-free period.

Current trends in critical care nutrition

Nutrition in the intensive care setting is a vital part of patient care, and may even be referred to as "nutritional therapy". Current nutritional practices have progressed a lot over the past few years, and draw from a large body of accumulating evidence. Yet, as with other trends in critical care, there are a lot of variations in the way nutrition is approached between institutions, as well as between individual physicians. This review attempts to look at some of these differences and provide recommendations based upon the available literature.

The fatty acid oxidation product 15-A3t-isoprostane is a potent inhibitor of NFκB transcription and macrophage transformation

Fatty acids such as eicosapentaenoic acid (EPA) have been shown to be beneficial for neurological function and human health. It is widely thought that oxidation products of EPA are responsible for biological activity, although the specific EPA peroxidation product(s) which exert these responses have not yet been identified. In this work we provide the first evidence that the synthesized representative cyclopentenone IsoP, 15-A(3t)-IsoP, serves as a potent inhibitor of lipopolysaccharide-stimulated macrophage activation. The anti-inflammatory activities of 15-A(3t)-IsoP were observed in response not only to lipopolysaccharide, but also to tumor necrosis factor alpha and IL-1b stimulation. Subsequently, this response blocked the ability of these compounds to stimulate nuclear factor kappa b (NFκB) activation and production of proinflammatory cytokines. The bioactivity of 15-A(3t)-IsoP was shown to be dependent upon an unsaturated carbonyl residue which transiently adducts to free thiols. Site directed mutagenesis of the redox sensitive C179 site of the Ikappa kinase beta subunit, blocked the biological activity of 15-A(3t)-IsoP and NFκB activation. The vasoprotective potential of 15-A(3t)-IsoP was underscored by the ability of this compound to block oxidized lipid accumulation, a critical step in foam cell transformation and atherosclerotic plaque formation. Taken together, these are the first data identifying the biological activity of a specific product of EPA peroxidation, which is formed in abundance in vivo. The clear mechanism linking 15-A(3t)-IsoP to redox control of NFκB transcription, and the compound's ability to block foam cell transformation suggest that 15-A(3t)-IsoP provides a unique and potent tool to provide vaso- and cytoprotection under conditions of oxidative stress.

Effect of ω-3 polyunsaturated fatty acids on hepatic tight junctions and liver regeneration in rats after partial hepatectomy

AIM: To investigate the effect of ω-3 polyunsaturated fatty acids (PUFAs) on hepatic tight junctions and liver regeneration in rats after partial hepatectomy (PH)

METHODS: A rat model of 70% PH was used in this study. Eighty male SD rats were randomly divided into sham operation group, PH group, PH + low-dose ω-3 PUFA (1 mL/kg) group and PH + high-dose ω-3 PUFA (2 mL/kg) group. Serum samples were collected to measure the levels of total bile acids, total bilirubin, alanine aminotransferase (ALT) and albumin on days 1, 2, 3 and 5 after PH. Tissue samples were collected for detecting the expression of hepatic tight junction proteins (Occludin, Claudin-3 and ZO-1) and PCNA (a parameter reflecting liver regeneration) by Western blot. Tissue samples were also collected for observation of structural changes in hepatic tight junctions by confocal microscopy.

RESULTS: In comparison with the PH group on day 1, the levels of total bile acids (181.2 ± 63.9, 166.7 ± 68.9 vs 228.9 ± 37.7), total bilirubin (13.5 ± 8.8, 7.6 ± 0.1 vs 25.9 ± 15.3) and ALT (1042.2 ± 179.7, 901.4 ± 182.3 vs 2703.9 ± 130.0) decreased significantly in the low- and high-dose ω-3 PUFA groups (all P < 0.05), whereas no marked changes in the level of albumin (27.2 ± 1.1, 29.8 ± 0.9 vs 30.5 ± 1.2) were observed. Compared to the PH group on day 2, a significant decrease in the levels of total bilirubin (6.8 ± 9.2, 6.1 ± 2.0 vs 17.7 ± 1.1) and ALT (452.8 ± 258.5, 499.8 ± 155.9 vs 1 466.5 ± 30.2) was noted in the low- and high-dose ω-3 PUFA groups (all P < 0.05), whereas no marked changes in the level of albumin (26.8 ± 0.4, 27.7 ± 1.0 vs 25.7 ± 0.6) were observed. The expression of hepatic tight junction proteins (Occludin, Claudin-3 and ZO-1) increased significantly on days 1, 2 and 5 after PH (all P < 0.05), and liver regeneration was enhanced significantly on days 1, 2, 3 and 5 after PH (all P < 0.05). Treatment with ω-3 PUFAs promoted structural restoration of hepatic tight junctions.

CONCLUSION: ω-3 PUFAs not only promote the expression of tight junction proteins and protect the structure of hepatic tight junctions but also promote liver regeneration and protect liver function in rats after PH.

Prevention and reversal of intestinal failure-associated liver disease in premature infants with short bowel syndrome using intravenous fish oil in combination with omega-6/9 lipid emulsions

Although premature infants with short bowel syndrome are at the highest risk of developing intestinal failure-associated liver disease (IFALD), they have great capacity for intestinal growth and adaptation if IFALD can be prevented. Conventional soybean oil-based intravenous lipid emulsions have been associated with IFALD. This study presents data on 5 premature neonates with short bowel syndrome treated with a combination of parenteral fish oil- and olive/soybean-based lipid emulsion for periods ranging between 7 and 17 months. Despite an enteral tolerance of less than 50% in 4 of these patients during their first year of life, direct bilirubin levels normalized while on this combination of ClinOleic (Baxter, Maurepas, France)/Omegaven (Fresenius Kabi, Bad Homburg, Germany) at a 1:1 ratio. None of our patients developed irreversible IFALD even though all of them were premature, had undergone multiple major surgical procedures, and had experienced several episodes of sepsis. Thus far, we have not seen any adverse effects of this mixed lipid emulsion in these preterm infants. All 5 patients are growing and developing well and have normal liver function.

Bacterial translocation is reduced by a specific nutritional combination in mice with chemotherapy-induced neutropenia

Immune function is compromised in many cancer patients, leading to an increased risk of (infectious) complications. Chemotherapy-induced neutropenia is a common cause of treatment-induced immune suppression. In the present study, the effect of a specific nutritional combination (SNC) on bacterial translocation was studied in a model of chemotherapy-induced neutropenia in C3H/HeN mice colonized with Pseudomonas aeruginosa PAO-1. Dietary intervention started after stable colonization with P. aeruginosa to compare the SNC containing high protein, l-leucine, fish oil, and specific oligosaccharides to an isoenergetic control diet. After 3 wk, the mice were treated with cyclophosphamide to induce neutropenia. This rendered the mice susceptible to Pseudomonas translocation, which was quantified 5 d later. Intervention with the SNC resulted in a reduced incidence and intensity of bacterial translocation to the liver (P < 0.05) and a similar trend in the lungs (P ≤ 0.057). In addition, the SNC reduced the fecal pH (P < 0.05) and decreased P. aeruginosa counts in fecal samples (P < 0.05). Moreover, plasma concentrations of proinflammatory cytokines were correlated with the reduced bacterial translocation to the liver (ρ > 0.78; P < 0.001). In conclusion, dietary intervention with the SNC significantly reduced the incidence and severity of P. aeruginosa translocation in a mouse model of chemotherapy-induced immune suppression. Several mechanisms might have played a role, including the modulation of the intestinal microbiota, an improved gut barrier function, immune function, and a reduced inflammatory state. These results suggest an opportunity to develop new applications in cancer patients, with the aim to reduce infectious and other complications.

Safety and efficacy of fish oil-enriched parenteral nutrition regimen on postoperative patients undergoing major abdominal surgery: a meta-analysis of randomized controlled trials

BACKGROUND

To evaluate the safety and efficacy of a fish oil-enriched parenteral nutrition regimen in patients undergoing major abdominal surgery, a meta-analysis of randomized controlled trials was conducted.

METHODS

An electronic search of PubMed, MEDLINE, EMBASE, Academic Search Premier, and China National Knowledge Infrastructure databases was performed in March 2009. RevMan 5.0 was used for statistical analysis.

RESULTS

The combined analysis showed that a fish oil-enriched parenteral nutrition regimen had a positive treatment effect on length of hospital stay (weighed mean difference = -2.98, P < .001), length of intensive care unit stay, postoperative infection rate (odds ratio = 0.56, P = .04), and serum levels of aspartate aminotransferase, alanine aminotransferase, and alpha-tocopherol on postoperative day 6 in these patients. The regimen increased the plasma levels of eicosapentaenoic acid (standardized mean difference = 3.11, P < .001) and docosahexaenoic acid and upregulated the leukotriene B(5) production in leukocytes on postoperative day 6. No significant differences were found between the 2 groups in postoperative mortality; incidence of postoperative cardiac complications; serum levels of bilirubin, triglyceride, or arachidonic acid; or the liberation of leukotriene B(4). No serious adverse events related to fish oil treatment were reported.

CONCLUSIONS

Based on the meta-analysis, fish oil-supplemented parenteral nutrition was safe, improved clinical outcomes, and altered the fatty acid pattern as well as leukotriene synthesis. More laboratory parameters should be considered in future meta-analyses.

Safety and efficacy of a lipid emulsion containing a mixture of soybean oil, medium-chain triglycerides, olive oil, and fish oil: a randomised, double-blind clinical trial in premature infants requiring parenteral nutrition

OBJECTIVES

Safety, tolerability, and efficacy of a novel lipid emulsion containing a mixture of soybean oil, medium-chain triglycerides, olive oil, and fish oil (SMOFlipid 20%) with reduced n-6 fatty acids (FA), increased monounsaturated and n-3 FA, and enriched in vitamin E were evaluated in premature infants compared with a soybean oil-based emulsion.

PATIENTS AND METHODS

Sixty (30/30) premature neonates (age 3-7 days, gestational age ≤ 34 weeks, birth weights 1000-2500 g) received parenteral nutrition (PN) with either SMOFlipid 20% (study group) or a conventional lipid emulsion (Intralipid 20%, control group) for a minimum of 7 up to 14 days. Lipid supply started at 0.5 g · kg body weight(-1) · day(-1) on day 1 and increased stepwise (by 0.5 g) up to 2 g · kg body weight(-1) · day(-1) on days 4 to 14. Safety and efficacy parameters were assessed on days 0, 8, and 15 if PN was continued.

RESULTS

Adverse events, serum triglycerides, vital signs, local tolerance, and clinical laboratory did not show noticeable group differences, confirming the safety of study treatment. At study end, γ-glutamyl transferase was lower in the study versus the control group (107.8 ± 81.7 vs 188.8 ± 176.7 IU/L, P < 0.05). The relative increase in body weight (day 8 vs baseline) was 5.0% ± 6.5% versus 5.1% ± 6.6% (study vs control, not significant). In the study group, an increase in n-3 FA in red blood cell phospholipids and n-3:n-6 FA ratio was observed. Plasma α-tocopherol (study vs control) was increased versus baseline on day 8 (26.35 ± 10.03 vs 3.67 ± 8.06 μmol/L, P < 0.05) and at study termination (26.97 ± 18.32 vs 8.73 ± 11.41 μmol/L, P < 0.05).

CONCLUSIONS

Parenteral infusion of SMOFlipid was safe and well tolerated and showed a potential beneficial influence on cholestasis, n-3 FA, and vitamin E status in premature infants requiring PN.

The 2008 ESPEN Sir David Cuthbertson Lecture: Fatty acids and inflammation--from the membrane to the nucleus and from the laboratory bench to the clinic

Many chronic conditions involve excessive inflammation that is damaging to host tissues. Excessive or inappropriate inflammation and immunosuppression are components of the response to surgery, trauma, injury and infection in some individuals and these can lead, progressively, to sepsis and septic shock. Hyperinflammation is characterised by the production of inflammatory cytokines, eicosanoids and other inflammatory mediators, while the immunosuppression is characterised by impairment of antigen presentation and of certain T cell responses. N-6 fatty acids may contribute to the hyperinflamed and immunosuppressed states. N-3 fatty acids from fish oil decrease the production of inflammatory cytokines and eicosanoids. They act both directly (by replacing arachidonic acid as an eicosanoid precursor) and indirectly (by altering the expression of inflammatory genes through effects on transcription factor activation). Thus, these fatty acids are potentially useful anti-inflammatory agents and may be of benefit in patients with chronic inflammatory diseases or at risk of hyperinflammation and sepsis. An emerging application of n-3 fatty acids is in surgical or critically ill patients where they may be added to parenteral or enteral formulas. Studies to date are suggestive of clinical benefits from these approaches, although more robust data are needed especially in critically ill patients.

Rationale and use of n-3 fatty acids in artificial nutrition

Lipids traditionally used in artificial nutrition are based on n-6 fatty acid-rich vegetable oils like soyabean oil. This may not be optimal because it may present an excessive supply of linoleic acid. One alternative to the use of soyabean oil is its partial replacement by fish oil, which contains n-3 fatty acids. These fatty acids influence inflammatory and immune responses and so may be useful in particular situations where those responses are not optimal. Fish oil-containing lipid emulsions have been used in parenteral nutrition in adult patients post-surgery (mainly gastrointestinal). This has been associated with alterations in patterns of inflammatory mediators and in immune function and, in some studies, a reduction in length of intensive care unit (ICU) and hospital stay. Perioperative administration of fish oil may be superior to post-operative. Parenteral fish oil has been used in critically ill adults. Here the influence on inflammatory processes, immune function and clinical endpoints is not clear, since there are too few studies and those that are available report contradictory findings. Fish oil is included in combination with other nutrients in various enteral formulas. In post-surgical patients and in those with mild sepsis or trauma, there is clinical benefit from a formula including fish oil and arginine. A formula including fish oil, borage oil and antioxidants has demonstrated marked benefits on gas exchange, ventilation requirement, new organ failures, ICU stay and mortality in patients with acute respiratory distress syndrome, acute lung injury or severe sepsis.

A novel effect of eicosapentaenoic acid: improved diaphragm strength in endotoxemia

Respiratory muscle weakness is commonplace in critically ill patients, impairing the ability of those patients to breath, prolonging the need for ventilatory support, and increasing the likelihood of respiratory failure when that support is removed. Infections and endotoxemia reduce respiratory muscle strength, probably acting through several mechanisms. It is reported that the omega-3 fatty acid eicosapentaenoic acid (EPA) attenuates the loss in diaphragm specific force generation (that is, diaphragm strength) induced by bacterial endotoxin treatment in rats. EPA is found in fish oils. EPA reduces calpain activation, suggesting a specific effect on this proteolytic pathway. It will be important to identify whether this effect occurs in patients receiving EPA.

Polyunsaturated fatty acids in the modulation of T-cell signalling

n-3 polyunsaturated fatty acids (PUFA) have been shown to modulate immune responses. These agents, being considered as adjuvant immunosuppressants, have been used in the treatment of various inflammatory and autoimmune diseases. However, the molecular mechanisms of action of n-3 PUFA-induced immunosuppressive effects are not well-understood. Since exogenous n-3 PUFA, under in vitro and in vivo conditions, are efficiently incorporated into T-cell plasma membranes, a number of recent studies have demonstrated that these agents may modulate T-cell signalling. In this review, the interactions of n-3 PUFA with the second messenger cascade initiated during early and late events of T-cell activation are discussed. We particularly focus on how these fatty acids can modulate the production of diacylglycerol and the activation of protein kinase C, mitogen activated protein kinase, calcium signalling and translocation of transcriptional factors, implicated in the regulation of gene transcription in T-cells.

Effects of a fish oil containing lipid emulsion on plasma phospholipid fatty acids, inflammatory markers, and clinical outcomes in septic patients: a randomized, controlled clinical trial

INTRODUCTION

The effect of parenteral fish oil in septic patients is not widely studied. This study investigated the effects of parenteral fish oil on plasma phospholipid fatty acids, inflammatory mediators, and clinical outcomes.

METHODS

Twenty-five patients with systemic inflammatory response syndrome or sepsis, and predicted to need parenteral nutrition were randomized to receive either a 50:50 mixture of medium-chain fatty acids and soybean oil or a 50:40:10 mixture of medium-chain fatty acids, soybean oil and fish oil. Parenteral nutrition was administrated continuously for five days from admission. Cytokines and eicosanoids were measured in plasma and in lipopolysaccharide-stimulated whole blood culture supernatants. Fatty acids were measured in plasma phosphatidylcholine.

RESULTS

Fish oil increased eicosapentaenoic acid in plasma phosphatidylcholine (P < 0.001). Plasma interleukin (IL)-6 concentration decreased significantly more, and IL-10 significantly less, in the fish oil group (both P < 0.001). At Day 6 the ratio PO2/FiO2 was significantly higher in the fish oil group (P = 0.047) and there were fewer patients with PO2/FiO2 <200 and <300 in the fish oil group (P = 0.001 and P = 0.015, respectively). Days of ventilation, length of intensive care unit (ICU) stay and mortality were not different between the two groups. The fish oil group tended to have a shorter length of hospital stay (22 +/- 7 vs. 55 +/- 16 days; P = 0.079) which became significant (28 +/- 9 vs. 82 +/- 19 days; P = 0.044) when only surviving patients were included.

CONCLUSIONS

Inclusion of fish oil in parenteral nutrition provided to septic ICU patients increases plasma eicosapentaenoic acid, modifies inflammatory cytokine concentrations and improves gas exchange. These changes are associated with a tendency towards shorter length of hospital stay.

TRIALS REGISTRATION

Clinical Trials Registration Number ISRCTN89432944.

Formulation of multifunctional oil-in-water nanosized emulsions for active and passive targeting of drugs to otherwise inaccessible internal organs of the human body

Oil-in-water (o/w) type nanosized emulsions (NE) have been widely investigated as vehicles/carrier for the formulation and delivery of drugs with a broad range of applications. A comprehensive summary is presented on how to formulate the multifunctional o/w NE for active and passive targeting of drugs to otherwise inaccessible internal organs of the human body. The NE is classified into three generations based on its development over the last couple of decades to make ultimately a better colloidal carrier for a target site within the internal and external organs/parts of the body, thus allowing site-specific drug delivery and/or enhanced drug absorption. The third generation NE has tremendous application for drug absorption enhancement and for 'ferrying' compounds across cell membranes in comparison to its first and second generation counterparts. Furthermore, the third generation NE provides an interesting opportunity for use as drug delivery vehicles for numerous therapeutics that can range in size from small molecules to macromolecules.

ESPEN Guidelines on Parenteral Nutrition: intensive care

Nutritional support in the intensive care setting represents a challenge but it is fortunate that its delivery and monitoring can be followed closely. Enteral feeding guidelines have shown the evidence in favor of early delivery and the efficacy of use of the gastrointestinal tract. Parenteral nutrition (PN) represents an alternative or additional approach when other routes are not succeeding (not necessarily having failed completely) or when it is not possible or would be unsafe to use other routes. The main goal of PN is to deliver a nutrient mixture closely related to requirements safely and to avoid complications. This nutritional approach has been a subject of debate over the past decades. PN carries the considerable risk of overfeeding which can be as deleterious as underfeeding. Therefore the authors will present not only the evidence available regarding the indications for PN, its implementation, the energy required, its possible complementary use with enteral nutrition, but also the relative importance of the macro- and micronutrients in the formula proposed for the critically ill patient. Data on long-term survival (expressed as 6 month survival) will also be considered a relevant outcome measure. Since there is a wide range of interpretations regarding the content of PN and great diversity in its practice, our guidance will necessarily reflect these different views. The papers available are very heterogeneous in quality and methodology (amount of calories, nutrients, proportion of nutrients, patients, etc.) and the different meta-analyses have not always taken this into account. Use of exclusive PN or complementary PN can lead to confusion, calorie targets are rarely achieved, and different nutrients continue to be used in different proportions. The present guidelines are the result of the analysis of the available literature, and acknowledging these limitations, our recommendations are intentionally largely expressed as expert opinions.

Rationale for using new lipid emulsions in parenteral nutrition and a review of the trials performed in adults

Lipids traditionally used in parenteral nutrition are based on n-6 fatty acid-rich vegetable oils such as soyabean oil. This practice may not be optimal because it may present an excessive supply of linoleic acid. Alternatives to the use of soyabean oil include its partial replacement by so-called medium-chain TAG (MCT), olive oil or fish oil, either alone or in combination. Lipid emulsions containing MCT are well established, but those containing olive oil and fish oil, although commercially available, are still undergoing trials in different patient groups. Emulsions containing olive oil or fish oil are well tolerated and without adverse effects in a wide range of adult patients. An olive oil–soyabean oil emulsion has been used in quite small studies in critically-ill patients and in patients with trauma or burns with little real evidence of advantage over soyabean oil or MCT–soyabean oil. Fish oil-containing lipid emulsions have been used in adult patients post surgery (mainly gastrointestinal). This approach has been associated with alterations in patterns of inflammatory mediators and in immune function and, in some studies, a reduction in the length of stay in the intensive care unit and in hospital. One study indicates that peri-operative administration of fish oil may be superior to post-operative administration. Fish oil has been used in critically-ill adults. Here, the influence on inflammatory processes, immune function and clinical end points is not clear, since there are too few studies and those that are available report contradictory findings. One important factor is the dose of fish oil required to influence clinical outcomes. Further studies that are properly designed and adequately powered are required in order to strengthen the evidence base relating to the use of lipid emulsions that include olive oil and fish oil in critically-ill patients and in patients post surgery.

Changing the paradigm: omegaven for the treatment of liver failure in pediatric short bowel syndrome

BACKGROUND

Parenteral omega-3 fatty acids, such as Omegaven, may benefit patients with pediatric short bowel syndrome (SBS) who develop parenteral nutrition-associated liver disease (PNALD).

PATIENTS AND METHODS

Retrospective cohort describing the outcome of all 12 children with SBS and advanced PNALD who were treated with Omegaven (target omega-6 to omega-3 fatty acid ratio = 1:1 to 2:1).

RESULTS

The median age was 7.5 (range 3.6-46) months, and median parenteral nutrition duration before starting Omegaven was 28.4 (range 15.3-55.3) weeks. Median initial serum conjugated bilirubin was 137 (range 54-203) micromol/L (8.06 [3.18-11.94] mg/dL). Of the 12 patients, 9 had complete and sustained resolution of hyperbilirubinemia within a median of 24 (range 7-37) weeks, and all are no longer being considered for liver transplantation. Improvements in markers of hepatic inflammation as well as nutritional status also were noted in these patients. Three patients received a liver-intestine transplant while taking Omegaven. There were no complications attributable to Omegaven.

CONCLUSIONS

Omegaven is associated with restoration of liver function in patients with SBS and advanced liver disease. Parenteral omega-3 fatty acids, such as Omegaven, have the potential to fundamentally alter the paradigm of neonatal SBS from one of early death or transplantation from liver failure to a more chronic disease. More children with SBS should achieve full enteral tolerance and those who do not have the capacity for intestinal adaptation should be able to survive and receive an intestinal graft when older.

120-Day Comparative Analysis of Adhesion Grade and Quantity, Mesh Contraction, and Tissue Response to a Novel Omega-3 Fatty Acid Bioabsorbable Barrier Macroporous Mesh After Intraperitoneal Placement

Purpose. This study aimed to evaluate adhesion formation, mesh contraction, and tissue response to an omega-3 fatty acid barrier—coated lightweight polypropylene mesh (C-Qur) after intra-abdominal placement, and compare these properties to those of other commercially available meshes. Materials and methods. After randomization, 3 × 3 cm pieces of Atrium C-Qur, Mesh ProLite Ultra, Composix, Parietex, Proceed, Sepramesh, and DualMesh were sewn to the intact peritoneum on either side of a midline incision in 41 New Zealand white rabbits. Necropsy was performed at 120 days, and explants were evaluated for adhesion grade, adhesion amount, and mesh contraction. Histologic evaluation included extent of capsule formation, abdominal wall tissue ingrowth, degrees of inflammation and vascularization of the surrounding tissue, and the presence of mesothelialization. Results. There were no significant differences between the C-Qur mesh and the commercially available meshes tested with regard to adhesion grade or amount, although percentage adhesion coverage for the C-Qur mesh was much less than for Composix and Proceed. The C-Qur mesh contracted less than all meshes, significantly less ( P < .05) than DualMesh or Proceed. DualMesh exhibited the greatest amount of capsule formation and inflammation on its parietal side as compared with the other meshes. Conclusions. Placing lightweight polypropylene mesh with an omega-3 fatty acid barrier coating intraperitoneally results in more favorable adhesion characteristics compared with Composix and Proceed meshes at 120-day explantation after intraperitoneal placement. The minimal amount of contraction and favorable tissue response in comparison to other commercially available meshes makes C-Qur mesh a practical alternative for laparoscopic and open ventral hernia repair.

The rationale for the use of parenteral omega-3 lipids in children with short bowel syndrome and liver disease

Parenteral nutrition associated liver disease (PNALD) is the major source of morbidity and mortality in children with short bowel syndrome (SBS). There is emerging evidence that omega-6 fatty acids (omega6FA) within the parenteral solution play a major role in PNALD and their effects may be reversed or ameliorated by substitution with omega-3 fatty acids (omega3FA). This paper reviews the mechanisms whereby omega3FAs may influence PNALD by improving bile flow, inhibiting steatosis, and having immunomodulatory effects. The early clinical experience with omega3FAs in SBS and PNALD is briefly reviewed and the implications of such, and future directions are considered.

Immunonutrition in surgical and critically ill patients

Surgery, trauma, burns and injury induce an inflammatory response that can become excessive and damaging in some patients. This hyperinflammation can be followed by an immunosuppressed state which increases susceptibility to infection. The resulting septic syndromes are associated with significant morbidity and mortality. A range of nutrients are able to modulate inflammation (and the associated oxidative stress) and to maintain or improve immune function. These include several amino acids, antioxidant vitamins and minerals, long-chain n-3 fatty acids and nucleotides. Experimental studies support a role for each of these nutrients in surgical, injured or critically ill patients. There is good evidence that glutamine influences immune function in such patients and that this is associated with clinical improvement. Evidence is also mounting for the use of long-chain n-3 fatty acids in surgical and septic patients, but more evidence of clinical efficacy is required. Mixtures of antioxidant vitamins and minerals are also clinically effective, especially if they include selenium. Their action appears not to involve improved immune function, although an anti-inflammatory mode of action has not been ruled out. Enteral immunonutrient mixtures, usually including arginine, nucleotides and long-chain n-3 fatty acids, have been used widely in surgical and critically ill patients. Evidence of efficacy is good in surgical patients. However whether these same mixtures are beneficial, or should even be used, in critically ill patients remains controversial, since some studies show increased mortality with such mixtures. There is a view that this is due to a high arginine content driving nitric oxide production.

Formation of highly reactive cyclopentenone isoprostane compounds (A3/J3-isoprostanes) in vivo from eicosapentaenoic acid

Omega-3 (omega-3) polyunsaturated fatty acids (PUFAs) found in marine fish oils are known to suppress inflammation associated with a wide variety of diseases. Eicosapentaenoic acid (EPA) is one of the most abundant omega-3 fatty acids in fish oil, but the mechanism(s) by which EPA exerts its beneficial effects is unknown. Recent studies, however, have demonstrated that oxidized EPA, rather than native EPA, possesses anti-atherosclerotic, anti-inflammatory, and anti-proliferative effects. Very few studies to date have investigated which EPA oxidation products are responsible for this bioactivity. Our research group has previously reported that anti-inflammatory prostaglandin A(2)-like and prostaglandin J(2)-like compounds, termed A(2)/J(2)-isoprostanes (IsoPs), are produced in vivo by the free radical-catalyzed peroxidation of arachidonic acid and represent one of the major products resulting from the oxidation of this PUFA. Based on these observations, we questioned whether cyclopentenone-IsoP compounds are formed from the oxidation of EPA in vivo. Herein, we report the formation of cyclopentenone-IsoP molecules, termed A(3)/J(3)-IsoPs, formed in abundance in vitro and in vivo from EPA peroxidation. Chemical approaches coupled with gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) were used to structurally characterize these compounds as A(3)/J(3)-IsoPs. We found that levels of these molecules increase approximately 200-fold with oxidation of EPA in vitro from a basal level of 0.8 +/- 0.4 ng/mg EPA to 196 +/- 23 ng/mg EPA after 36 h. We also detected these compounds in significant amounts in fresh liver tissue from EPA-fed rats at basal levels of 19 +/- 2 ng/g tissue. Amounts increased to 102 +/- 15 ng/g tissue in vivo in settings of oxidative stress. These studies have, for the first time, definitively characterized novel, highly reactive A/J-ring IsoP compounds that form in abundance from the oxidation of EPA in vivo.

Home parenteral nutrition in advanced cancer: where are we?

Patients with advanced and incurable cancer are a compelling group. Questions and comments that these individuals and their families have may include: “My daughter is expecting our first grandchild in 3 months — can I hope to see our new family member?”; “I can’t keep any food down — is there anything I can do?”; “I am worried about losing so much weight, and feeling tired and weak — is there anything that may help?”; “Will I suffer a lot?”. Indeed, the most pressing concerns of the patient relate to predictions about survival and control of symptoms. The clinician taking care of the patient may wonder what is the utility or futility of home parenteral nutrition (HPN) in both the individual with advanced cancer and in this population of patients at large, whether there is potential for harm such as increasing the burden of care or prolonging suffering, and how to optimize care and communication with the patient and their families. The nutrition scientist may want to know what the implications of advanced cancer are on nutrient requirements and utilization, whether there are markers that would differentiate between cachexia and simple starvation, and whether it is possible to use specific nutrients to modify the disease process. This review will provide insights into the understanding of the role of HPN in advanced cancer and opportunities for further investigation.

Gender differences in then-3 fatty acid content of tissues

Dietaryn-3 PUFA have many beneficial effects on cell and tissue function and on human health. In mammals then-3 essential fatty acid α-linolenic acid (ALNA) can be converted into longer-chain (LC)n-3 PUFA such as EPA and DHA via a series of desaturase and elongase enzymes that are mainly active in the liver. Human studies have identified that males and females appear to differ in their ability to synthesise EPA and DHA from ALNA, with associated differences in circulating concentrations. Based on studies of women using the contraceptive pill or hormone-replacement therapy and of trans-sexual subjects it is suggested that sex hormones play a role in these differences. The rat has been used to investigate gender differences inn-3 PUFA status since this model allows greater dietary control than is possible in human subjects. Like human subjects, female rats have higher plasma DHA concentrations than males. Rats also respond to increased dietary ALNA in a way that is comparable with available human data. The concentrations of LCn-3 PUFA in rat plasma and tissues are positively associated with circulating concentrations of oestradiol and progesterone and negatively associated with circulating concentrations of testosterone. These findings suggest that sex hormones act to modify plasma and tissuen-3 PUFA content, possibly by altering the expression of desaturase and elongase enzymes in the liver, which is currently under investigation.