Omega-3 vs. omega-6 lipid emulsions exert differential influence on neutrophils in septic shock patients: impact on plasma fatty acids and lipid mediator generation

Pretreatment with an intravenous lipid emulsion increases plasma eicosapentanoic acid and downregulates leukotriene b4, procalcitonin, and lymphocyte concentrations after open heart surgery in infants

BACKGROUND

The effect of providing a lipid emulsion containing medium-chain triglyceride (MCT), soybean oil, and fish oil in critically ill infants is not widely studied. This study investigated lipid emulsion effects on plasma phospholipids and immune biomarkers.

MATERIALS AND METHODS

Thirty-two infants undergoing cardiopulmonary bypass (CPB) and dependent on parenteral nutrition (PN) were randomized to receive either soybean oil (control, n = 16) or a 50:40:10 mixture of MCT, soybean oil, and fish oil (treatment, n = 16). PN was administered for 3 days preoperatively and 10 days postoperatively. Fatty acids, procalcitonin (PCT), leukotriene B4 (LTB4), and lymphocytes were quantified at baseline, before surgery, and days 1, 7 and 10 after surgery.

RESULTS

PCT was significantly lower in the treatment vs control group 1 day postoperatively (P = .01). The treatment group exhibited a lower ω-6 to ω-3 ratio (P = .0001) and a higher ω-3 concentration at all postoperative study periods (P = .001). Treatment resulted in higher (P < .05) plasma phospholipid eicosapentaenoic acid (EPA) on days 7 and 10, while α-linolenic acid, arachidonic acid, and docosahexaenoic acid remained constant. An increase in plasma phospholipid EPA concentration was associated with a decrease in plasma phospholipid LTB4 concentration (P < .05). On postoperative day 10, treatment infants with high Pediatric Risk of Mortality III scores exhibited a 45% lower lymphocyte concentration (P < .05).

CONCLUSION

These findings suggest that treating infants undergoing CPB with a lipid emulsion containing ω-3 improves fatty acid status and results in a lower inflammatory response after surgery. Overall, this alternative ω-3-enriched lipid emulsion may benefit clinical outcomes of critically ill infants after cardiac surgery.

High capacity for leukotriene biosynthesis in peripheral blood during pregnancy

Pregnancy is accompanied by major immunological changes to maintain both tolerance for the fetus and immune competence. Leukotrienes are powerful 5-lipoxygenase-derived inflammatory mediators and the characteristics of leukotriene-related diseases (e.g., asthma, allergic rhinitis) change during pregnancy. Here, we show that pregnancy affects leukotriene synthesis in human blood and leukocytes. 5-Lipoxygenase product formation in stimulated blood of pregnant women was significantly higher than in non-pregnant females. Although a pregnancy-related increase in neutrophil and monocyte counts may explain these observations, granulocytes of pregnant donors have lower leukotriene-synthetic capacities. On the other hand, granulocytes from non-pregnant woman produced more leukotrienes when resuspended in plasma of pregnant women than of non-pregnant females. Together, we show that leukotriene biosynthesis in maternal blood is increased by the interrelations of higher leukocyte numbers, lower cellular capacity for leukotriene synthesis and stimulatory effects of plasma. This bias may affect leukotriene-related diseases during pregnancy and their pharmacological treatment.

Lipid emulsions in parenteral nutrition: current applications and future developments

INTRODUCTION

A parenteral lipid emulsion (LE), used as a key source of energy, essential fatty acids (FAs), and fat-soluble vitamins, is an integral part of a parenteral nutrition (PN) regimen. The conventional LEs, such as soybean oil (SO)-based emulsions, have caused concerns about the potential adverse effects involving oxidative stress, inflammation, and immune response probably because of undesirable FA composition.

AREAS COVERED

Recently, alternative LEs, optimizing the FA composition with partial substitution of SO with medium-chain triglyceride (MCT), olive oil (OO), and fish oil (FO), have been developed and applied in clinical practice. This review summarizes the characteristics and beneficial clinical effects of alternative parenteral LEs in critically ill, pediatric, and long-term PN patients.

EXPERT OPINION

More clinical data from sufficiently high-powered studies are required to characterize the integral biological properties of alternative LEs for further selection to fit individual needs and disease characteristics. Simultaneously, potential lipid sources with desirable FA compositions and biological properties should be selected to develop new therapeutic LEs. As supplements to current parenteral lipids, the new LEs with different therapeutic effects are expected to fit specified subpopulations of patients with different diseases. Great efforts should be devoted to the development of parenteral LEs.

Alternative lipid emulsions in the critically ill: a systematic review of the evidence

PURPOSE

Parenteral lipid emulsions (LEs) are commonly rich in long-chain triglycerides derived from soybean oil (SO). SO-containing emulsions may promote systemic inflammation and therefore may adversely affect clinical outcomes. We hypothesized that alternative oil-based LEs (SO-sparing strategies) may improve clinical outcomes in critically ill adult patients compared to products containing SO emulsion only. The purpose of this systematic review was to evaluate the effect of parenteral SO-sparing strategies on clinical outcomes in intensive care unit (ICU) patients.

METHODS

We searched computerized databases from 1980 to 2013. We included randomized controlled trials (RCTs) conducted in critically ill adult patients that evaluated SO-sparing strategies versus SO-based LEs in the context of parenteral nutrition.

RESULTS

A total of 12 RCTs met the inclusion criteria. When the results of these RCTs were statistically aggregated, SO-sparing strategies were associated with clinically important reductions in mortality (risk ratio, RR 0.83; 95 % confidence intervals, CI 0.62, 1.11; P = 0.20), in duration of ventilation (weighted mean difference, WMD -2.57; 95 % CI -5.51, 0.37; P = 0.09), and in ICU length of stay (LOS) (WMD -2.31; 95 % CI -5.28, 0.66; P = 0.13) but none of these differences were statistically significant. SO-sparing strategies had no effect on infectious complications (RR 1.13; 95 % CI 0.87, 1.46; P = 0.35).

CONCLUSION

Alternative oil-based LEs may be associated with clinically important reductions in mortality, duration of ventilation, and ICU LOS but lack of statistical precision precludes any clinical recommendations at this time. Further research is warranted to confirm these potential positive treatment effects.

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.

Parenteral fish oil lipid emulsions in the critically ill: a systematic review and meta-analysis

INTRODUCTION

ω-3 Polyunsaturated fatty acids contained in fish oils (FO) possess major anti-inflammatory, antioxidant, and immunologic properties that could be beneficial during critical illness. We hypothesized that parenteral FO-containing emulsions may improve clinical outcomes in the critically ill.

METHODS

We searched computerized databases from 1980-2012. We included randomized controlled trials (RCTs) conducted in critically ill adult patients that evaluated FO-containing emulsions, either in the context of parenteral nutrition (PN) or enteral nutrition (EN).

RESULTS

A total of 6 RCTs (n = 390 patients) were included; the mean methodological score of all trials was 10 (range, 6-13). When the results of these studies were aggregated, FO-containing emulsions were associated with a trend toward a reduction in mortality (risk ratio [RR], 0.71; 95% confidence interval [CI], 0.49-1.04; P = .08; heterogeneity I (2) = 0%) and a reduction in the duration of mechanical ventilation (weighted mean difference in days [WMD], -1.41; 95% CI, -3.43 to 0.61; P = .17). However, this strategy had no effect on infections (RR, 0.76; 95% CI, 0.42-1.36; P = .35) and intensive care unit length of stay (WMD, -0.46; 95% CI, -4.87 to 3.95; P = .84, heterogeneity I (2) = 75%).

CONCLUSION

FO-containing lipid emulsions may be able to decrease mortality and ventilation days in the critically ill. However, because of the paucity of clinical data, there is inadequate evidence to recommend the routine use of parenteral FO. Large, rigorously designed RCTs are required to elucidate the efficacy of parenteral FO in the critically ill.

Oleic, linoleic and linolenic acids increase ros production by fibroblasts via NADPH oxidase activation

The effect of oleic, linoleic and γ-linolenic acids on ROS production by 3T3 Swiss and Rat 1 fibroblasts was investigated. Using lucigenin-amplified chemiluminescence, a dose-dependent increase in extracellular superoxide levels was observed during the treatment of fibroblasts with oleic, linoleic and γ-linolenic acids. ROS production was dependent on the addition of β-NADH or NADPH to the medium. Diphenyleneiodonium inhibited the effect of oleic, linoleic and γ-linolenic acids on fibroblast superoxide release by 79%, 92% and 82%, respectively. Increased levels of p47^phox phosphorylation due to fatty acid treatment were detected by Western blotting analyses of fibroblast proteins. Increased p47^phox mRNA expression was observed using real-time PCR. The rank order for the fatty acid stimulation of the fibroblast oxidative burst was as follows: γ-linolenic > linoleic > oleic. In conclusion, oleic, linoleic and γ-linolenic acids stimulated ROS production via activation of the NADPH oxidase enzyme complex in fibroblasts.

Pharmaconutrition: acute fatty acid modulation of circulating cytokines in elderly patients in the ICU

BACKGROUND

Enteral supply of ω-3 polyunsaturated fatty acids has been used in an attempt to modulate inflammation and improve outcome in critically ill patients. However, enteral administration may be slow to change membrane composition and therefore may not be the best route to supply these fatty acids in patients with acute conditions. This study evaluated the effects of short-term intravenous (IV) administration of fish oil-based lipid emulsion (FLE) as pharmaconutrition on cytokine levels in critically ill elderly patients.

METHODS

Enterally fed patients (n = 40; aged 60-80 years) were recruited in the first 48 hours of intensive care unit (ICU) admission. Fifteen patients received IV FLE (0.2 g/kg body weight) over 6 hours for 3 consecutive days, and 25 patients did not receive IV lipid (control). Samples were collected before and 24 hours and 72 hours after the third FLE infusion. Nutrient intakes, clinical parameters, and serum cytokine concentrations were measured.

RESULTS

Compared with the control, FLE resulted in higher energy intake, lower serum tumor necrosis factor-α and interleukin (IL)-8 concentrations, and higher serum IL-10. These differences occurred around 7-9 days of ICU stay at the time of the patient's extubation. ICU stay, mortality, and markers of coagulation and liver function did not differ between groups.

CONCLUSIONS

Short-term IV FLE modulates some inflammatory markers in critically ill elderly patients receiving enteral nutrition (EN), suggesting an anti-inflammatory effect. This may be a benefit and suggests a role for FLE administration as a supplement in elderly ICU patients receiving standard EN.

The role of ω-3 fatty acid supplemented parenteral nutrition in critical illness in adults: a systematic review and meta-analysis

OBJECTIVE

To determine whether the supplementation of parenteral nutrition with ω-3 fatty acids confers treatment benefits to critically ill adult patients.

DATA SOURCE

We performed computerized searches for relevant articles from 1996 to June 2011 on MEDLINE, EMBASE, and the Cochrane register of controlled trials and abstracts of scientific meetings from 2005 to 2011.

STUDY SELECTION

Randomized controlled trials of ω-3 fatty acid supplemented parenteral nutrition in critically ill adult patients admitted to the intensive therapy unit, given in addition to their routine care, compared with parenteral nutrition without ω-3 fatty acid supplementation.

DATA SYNTHESIS

Five fully published trials and three trials published in abstract form with 391 participants have been included. Overall trial quality was poor. Mortality data were pooled from eight studies with 391 participants. No differences were found with a risk ratio for death of 0.83 (95% confidence interval 0.57, 1.20; p = 0.32). Data for infectious complications were available from five studies with 337 participants. No differences were found, with a risk ratio for infection of 0.78 (95% confidence interval 0.43, 1.41; p = 0.41). Data for intensive therapy unit and hospital length of stay were available from six and three studies with 305 and 117 participants, respectively. With respect to intensive therapy unit length of stay, no differences were observed with a mean difference of 0.57 days in favor of the ω-3 fatty acid group (95% confidence interval -5.05, 3.90; p = 0.80). A significant reduction in hospital length of stay of 9.49 days (95% confidence interval -16.51, -2.47; p = 0.008) was observed for those receiving ω-3 fatty acid supplemented parenteral nutrition, but results were strongly influenced by one small study.

CONCLUSIONS

On the basis of this systematic review, it can be concluded that ω-3 fatty acid supplementation of parenteral nutrition does not improve mortality, infectious complications, and intensive therapy unit length of stay in comparison with standard parenteral nutrition. Although ω-3 fatty acids appear to reduce hospital length of stay, the poor methodology of the included studies and the absence of other outcome improvements mean they cannot be presently recommended.

Supplemental intravenous n-3 fatty acids and n-3 fatty acid status and outcome in critically ill elderly patients in the ICU receiving enteral nutrition

BACKGROUND & AIMS

N-3 fatty acids (FA) may have benefits in ICU patients. The aims were to identify whether FA status is altered in critical illness and to evaluate the effect of supplemental intravenous n-3 FA on plasma FA status and clinical outcome in ICU patients receiving enteral nutrition.

METHODS

Enterally fed patients (n = 49; 60-80 years) were recruited in the first 48 h of ICU admission. Fifteen patients received n-3 FA emulsion (0.2 g/kg) over 6 h for 3 consecutive days, and 34 patients did not (control). Samples were collected before supplementation, and 24 and 72 h after the third infusion. Nineteen healthy elderly subjects were also studied; they gave a single blood sample. FA were measured in plasma phosphatidylcholine (PC).

RESULTS

Critically ill patients had altered plasma PC FA compared with healthy elderly subjects. Surviving ICU patients had higher levels of docosahexaenoic acid and total n-3 FA and a lower ratio of n-6:n-3 FA in plasma PC than non-survivors. Infusion of n-3 FA increased eicosapentaenoic, docosahexaenoic and total n-3 FA, and decreased arachidonic and total n-6 FA and n-6:n-3 FA and arachidonic:eicosapentaenoic acid ratios. Gas exchange was enhanced 72 h after the third n-3 FA infusion (p = 0.001).

CONCLUSIONS

Critically ill patients may have altered plasma FA profiles. A higher total n-3 FA and docosahexaenoic acid content in plasma PC is associated with survival and improved gas exchange.

Parenteral omega-3 fatty acids: pouring oil on troubled waters?

A meta-analysis of parenteral fish oil in 23 studies in intensive care unit (ICU) and non-ICU patients reported a reduced infection rate (significant in ICU patients) and shorter lengths of ICU and hospital stays (both non-ICU and ICU patients). Parenteral fish oil reduced inflammation and improved oxygenation index and liver function. The findings of the meta-analysis are discussed in this report.

Impact of supplementing preoperative intravenous omega 3 Fatty acids in fish oil on immunomodulation in elderly patients undergoing hip surgery

The aim of this study was to evaluate the immunomodulatory effects of supplementing intravenous omega-3 fatty acids in fish oil (IVFO) in elderly patients undergoing hip surgery. This was a single centre, randomized, controlled, comparative, phase IV study in elderly patients undergoing hip surgery. The subjects, within the age range of 50-90 years, were assigned randomly to the group receiving intravenous omega-3 fatty acids in fish oil (IVFO, Omegaven®) or the control group not receiving intravenous fish oil (n = 20 in each group). IL-6, IL-8, IL-10, and HS-CRP levels were the inflammatory markers assessed in this study. The within-group comparison was done by paired t-test and between-group comparison by unpaired t-test. At day 4, IL-6 values in the IVFO group decreased as compared to day 0. At day 4, IL-8 mean values increased for both IVFO and control groups. This increase was highly significant in the control group (P = 0.0182). IL 10 values decreased at day 4 and increased at day 8 in the IVFO group. Increase in HS-CRP levels was nonsignificant at day 4 in the IVFO group (P = 0.60) and significant at day 8 for the control group (P = 0.0084) as compared to day 0. Various biochemical parameters including albumin, protein, SGOT, SGPT, blood glucose, and urea values generated evidence regarding the safety profile of IVFO. This study suggests a role for IVFO in the short-term suppression of inflammatory mediators for patients undergoing hip surgery. However, further, larger trials may be needed to establish its definitive role in this patient population.

Comparison of the effects of different intravenous fat emulsions in patients with systemic inflammatory response syndrome and sepsis

BACKGROUND

In this study, the authors aimed to compare the effects that a medium- and long-chain triglyceride (MCT/LCT) fat infusion and a fish oil-based (ω-3) fat infusion for parenteral nutrition (PN) had on systemic inflammation, cytokine response, and hepatic steatosis in mixed intensive care unit (ICU) patients.

METHODS

This was a single-center, placebo-controlled, randomized clinical trial in a university hospital. Four patient groups, including systemic inflammatory response syndrome (SIRS) and sepsis patients, were assigned to receive PN employing the MCT/LCT fat infusion or the fish oil-based fat infusion over 7 days. Blood biochemistry and liver steatosis were evaluated.

RESULTS

Twenty sepsis and 20 SIRS patients were included in this study. There was no statistically significant difference in terms of biochemical values and Acute Physiology and Chronic Health Evaluation II scores between the different feeding groups. Sepsis groups who received MCT/LCT revealed higher grades of liver steatosis by ultrasound on days 7 and 10 (P < .05). Tumor necrosis factor (TNF)-α and interleukin (IL)-6 values in sepsis group 1 (S1) were higher than in sepsis group (S2) on day 7, whereas IL-1 values were higher on days 3, 7, and 10 in group S1 than in group S2. Conversely, IL-10 values on days 3 and 7 were significantly higher in group S2.

CONCLUSION

Fish oil-based fat emulsions might have anti-inflammatory and hepatoprotective effects in hyperinflammatory disease such as sepsis.

Dietary fish oil decreases the proportion of classical monocytes in blood in healthy mice but increases their proportion upon induction of inflammation

Fish oil can have beneficial effects in health and disease. In healthy individuals, reduction of the inflammatory status may be of benefit, whereas in patients with systemic inflammation, such as sepsis, it is important to diminish the immunosuppression that is thought to contribute to poor outcome. The objective of this study was to determine the effects of dietary fish oil on monocytes/macrophages in blood, bone marrow, spleen, and peritoneum and chemokine concentrations in blood and peritoneum in healthy mice and mice with endotoxin-induced inflammation. Mice were fed a Western-type diet without fish oil (C) or with 2.8% fish oil (FO) for 6 wk and then either killed (healthy mice) or injected i.p. with endotoxin (LPS) and killed after 3, 8, 12, 24, or 48 h. Blood, bone marrow, spleen, and peritoneal lavage were collected. Expression of cell surface molecules and chemokine receptors was analyzed by flow cytometry and chemokine concentrations measured by ELISA. Healthy mice in the FO group had lower proportions of classical monocytes in blood than healthy mice in the C group. LPS administration increased the proportion of classical monocytes in blood in mice in the FO group but not in those in the C group. Healthy mice in the FO group had lower serum concentrations of CCL2 than mice in the C group, but in inflamed mice, CCL2 concentrations were higher in the FO group than in the C group. These results indicate that dietary fish oil can attenuate the inflammatory status in homeostasis but intensify the immune response upon inflammation.

The effect of dietary fatty acids on post-operative inflammatory response in a porcine model

The potential anti-inflammatory effects of dietary fish oil (FO) have been studied in numerous clinical trials. However, variation in lifestyle and morbidity among patients can be difficult to control. In the present study, the impact of a 3-week dietary pre-treatment with 10% (w/w) FO (n 28), sunflower oil (SO, n 28), or animal fat (AF, n 28) was evaluated with respect to post-operative responses in inflammatory markers in a porcine model on aortic vascular prosthetic graft infection. In the early post-operative period (0 < day ≤ 3), FO suppressed whole blood IL-8 and tumor necrosis factor-α responsiveness to LPS stimulation, decreased peripheral leukocyte IL-8 mRNA abundance, reinforced an increase in total leukocyte count, and counteracted a decrease in mononuclear leukocyte count compared with SO. In the late post-operative period (3 < day ≤ 14), FO increased total leukocyte count and showed higher maximum CRP and haptoglobin concentrations compared with SO. Compared with AF, FO decreased peripheral leukocyte IL-8 mRNA abundance in the early post-operative period, and increased total leukocyte count and maximum CRP concentration in the late post-operative period. In conclusion, the post-operative response in a number of inflammatory markers was affected by FO, and this was most apparent compared with SO.

Effects of fish oil on inflammatory modulation in surgical intensive care unit patients

BACKGROUND

The benefit of ω-3 fatty acids in fat emulsion remains controversial. This study evaluated the effect of ω-3 fatty acids on immune and inflammatory modulation in surgical intensive care unit (SICU) patients.

METHODS

Thirty-eight patients admitted to the SICU after major surgery were enrolled in this prospective controlled study and randomized to receive parenteral nutrition (PN) with equal volume and calories from glucose, nitrogen, and fat but different lipid components for 7 postoperative days. Group A (n = 12) received a mixture of soybean and medium-chain triglyceride oils; group B (n = 18) received a fat emulsion with part of the lipid replaced by fish oil. Blood tests, including lipid profile, routine biochemistry, inflammatory cytokines, and lymphocyte subpopulations, were evaluated preoperatively and on postoperative days 4 and 7.

RESULTS

Both lipid regimens were well tolerated. There was a trend toward reduced serum inflammatory cytokines in group B vs group A with significant differences regarding interleukin (IL)-1, IL-8, and interferon (IFN)-γ on postoperative day 4 (P < .05) and IL-1, IL-8, IFN-γ, IL-6, and tumor necrosis factor-α on postoperative day 7 (P < .05). There was a reduction in postoperative liver dysfunction (A vs B: 50% vs 33.3%) and infection rate (A vs B: 41.7% vs 27.8%) in group B, although this was not statistically significant. There was no mortality in either group.

CONCLUSION

This study suggests that supplementation of parenteral ω-3 fatty acids in PN is safe and may improve immune and hyperinflammatory response for SICU patients after major surgery.

Antioxidant strategies in neurocritical care

An increase in oxidative stress and overproduction of oxidizing reactive species plays an important role in the pathophysiology of several conditions encountered in the neurocritical care setting including: ischemic and hemorrhagic strokes, traumatic brain injury, acute respiratory distress syndrome, sepsis, and organ failure. The presence of oxidative stress in these conditions is supported by a large body of pre-clinical and clinical studies, and provides a rationale to support a potential therapeutic role for antioxidants. The purpose of this article is to briefly review the basic mechanisms and molecular biology of oxidative stress, summarize its role in critically ill neurological patients, and review available data regarding the potential role of antioxidant strategies in neurocritical care and future directions.

Pre-treatment with an intravenous lipid emulsion containing fish oil (eicosapentaenoic and docosahexaenoic acid) decreases inflammatory markers after open-heart surgery in infants: a randomized, controlled trial

BACKGROUND & AIMS

This study assessed the effects of administering a lipid emulsion containing eicosapentaenoic and docosahexaenoic acid before and after open-heart surgery on cytokine production and length of hospital stay in infants.

METHODS

Thirty-two infants (40 ± 2.3 weeks gestational age; 10.6 days at time of surgery) undergoing open-heart surgery with cardiopulmonary bypass were randomized to receive an intravenous lipid emulsion with (treatment) or without (control) eicosapentaenoic and docosahexaenoic acid in this prospective, randomized, double-blind, controlled trial.

RESULTS

Mean plasma TNF-α concentration was significantly (p = 0.003) lower in the treatment (5.9 pg/mL) compared to the control group (14.8 pg/mL). In infants without sepsis, plasma TNF-α did not differ according to treatment, however when sepsis developed, mean plasma TNF-α was 21.1 pg/mL and 1.5 pg/mL (p = 0.0007) in control and treatment groups, respectively. Plasma TNF-α was positively correlated with length of hospital stay in the control group (p = 0.01), and negatively correlated with length of stay in the treatment group (p = 0.004), with a significant time by treatment interaction (p = 0.02).

CONCLUSIONS

Providing a lipid emulsion containing eicosapentaenoic and docosahexaenoic acid reduces TNF-α concentrations in infants undergoing open-heart surgery. Lipid emulsions containing eicosapentaenoic and docosahexaenoic acid may ameliorate the inflammatory response among critically ill infants.

Superiority of a fish oil-enriched emulsion to medium-chain triacylglycerols/long-chain triacylglycerols in gastrointestinal surgery patients: a randomized clinical trial

OBJECTIVE

Compared with soybean oil, a fish oil-enriched emulsion can improve the clinical outcomes of patients requiring parenteral nutrition. However, the superiority of fish oil emulsion to medium-chain triacylglycerols/long-chain triacylglycerols for short-term administration has seldom been discussed.

METHODS

Sixty-four adult patients with gastrointestinal diseases were randomly assigned to receive isocaloric and isonitrogenous total parenteral nutrition with an ω-3 fatty acid-enriched emulsion (Lipoplus; study group, n = 32) or medium-chain triacylglycerols/long-chain triacylglycerols (Lipofundin; control group, n = 32) for 5 d after surgery. Safety and efficacy parameters were assessed on postoperative days 1, 3, and 6.

RESULTS

Clinical outcomes including infectious complications and systemic inflammatory response syndrome were comparable between the two groups. Total bilirubin decreased over time in the study group versus an increase in the control group (P = 0.017). Activated partial thromboplastin time in the study group was prolonged significantly compared with the control group from days 1 to 3 (P = 0.002), although the prolongation stopped at the study termination. There were no differences in changes of C-reactive protein, interleukin (IL)-1, IL-8, IL-10, vascular endothelial growth factor (VEGF), and the distribution of the T-cell subpopulation between the two groups. However, fish oil consumption led to an increase in leukotriene B5/ leukotriene B4 and significant decreases in IL-6, tumor necrosis factor-α, and nuclear factor-κB. Furthermore, the overall changes in tumor necrosis factor-α and nuclear factor-κB were positively associated (R(2) = 0.295, P < 0.001).

CONCLUSIONS

Gastrointestinal surgery patients benefited from a fish oil-enriched emulsion rather than medium-chain triacylglycerols/long-chain triacylglycerols in the amelioration of liver function and immune status. The positive association of tumor necrosis factor-α and nuclear factor-κB might be involved in the potential anti-inflammation mechanism of fish oil.

Efficacy and safety of parenteral omega 3 fatty acids in ventilated patients with acute lung injury

Objective:

To determine the effects of parenteral omega 3 fatty acids (10% fatty acids) on respiratory parameters and outcome in ventilated patients with acute lung injury.

Measurements and Main Results:

Patients were randomized into two groups – one receiving standard isonitrogenous isocaloric enteral diet and the second receiving standard diet supplemented with parenteral omega 3 fatty acids (Omegaven, Fresenius Kabi) for 14 days. Patients demographics, APACHE IV, Nutritional assessment and admission category was noted at the time of admission. No significant difference was found in nutritional variables (BMI, Albumin). Compared with baseline PaO²/FiO² ratio (control vs. drug group: 199 ± 124 vs. 145 ± 100; P = 0.06), by days 4, 7, and 14, patients receiving the drug did not show a significant improvement in oxygenation (PaO²/FiO²: 151.83 ± 80.19 vs. 177.19 ± 94.05; P = 0.26, 145.20 ± 109.5 vs. 159.48 ± 109.89; P = 0.61 and 95.97 ± 141.72 vs. 128.97 ± 140.35; P = 0.36). However, the change in oxygenation from baseline to day 14 was significantly better in the intervention as compared to control group (145/129 vs. 199/95; P < 0.0004). There was no significant difference in the length of ventilation (LOV) and length of ICU stay (LOS). There was no difference in survival at 28 days. Also, there was no significant difference in the length of ventilation and ICU stay in the survivors group as compared to the non survivors group.

Conclusions:

In ventilated patients with acute respiratory distress syndrome, intravenous Omega 3 fatty acids alone do not improve ventilation, length of ICU stay, or survival.

Lipids in critical care medicine

While enteral nutrition is the basis for the critically ill, parenteral nutrition is often used when a sufficient enteral nutrition is not or not fully achievable. Lipids are a mainstay of caloric supply in both cases as they combine the provision of building blocks for the membranes and are precursors for function molecules including lipid mediators bearing the ability to influence immunity. Pro-inflammatory lipid mediators as prostaglandins and leukotrienes are generated from arachidonic acid (AA), a key member of the n-6 polyunsaturated fatty acids (PUFA). In contrast, lipid mediators derived from the n-3 fatty acids eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) may exhibit less inflammatory properties compared to their AA-derived counterparts. Furthermore, intercellular mediators as resolvins and protectins are generated from n-3 fatty acids. They induce the resolution of inflammation, hence the name resolution phase interaction product-resolvin. Modulating the amount of PUFA and the n-6/n-3 ratio were investigated as means to change the inflammatory response and improve the outcome of patients. Experimental data showed that n-3 fatty acids may improve acute lung injury and sepsis in animal models. Studies in patients undergoing major surgery with application of n-3 fatty acids demonstrated beneficial effects in terms of reduction of length of stay and infectious complications. Clinical data hints that this concept may also improve outcome in critically ill patients. Additionally, experimental and clinical data suggest that a reduction in n-6 PUFA may change the immune response. In conclusion, modulating the amount of PUFA, the n-6/n-3 ratio and the composition of lipid emulsions may prove to be a useful means to improve the outcome of critically ill patients.

n-3 PUFAs in cancer, surgery, and critical care: a systematic review on clinical effects, incorporation, and washout of oral or enteral compared with parenteral supplementation

BACKGROUND

n-3 (omega-3) Fatty acids (FAs) may have beneficial effects in patients with cancer or in patients who undergo surgery or critical care.

OBJECTIVE

Our aim was to systematically review the effects of oral or enteral and parenteral n-3 FA supplementation on clinical outcomes and to describe the incorporation of n-3 FAs into phospholipids of plasma, blood cells, and mucosal tissue and the subsequent washout in these patients.

DESIGN

We investigated the supplementation of n-3 FAs in these patients by using a systematic literature review.

RESULTS

In cancer, the oral or enteral supplementation of n-3 FAs contributed to the maintenance of body weight and quality of life but not to survival. We did not find any studies on parenteral supplementation of n-3 FAs in cancer. In surgical oncology, we did not find any studies on enteral supplementation of n-3 FAs. However, postoperative parenteral supplementation in surgical oncology may reduce the length of a hospital stay. For general surgery, we did not find any studies on enteral supplementation of n-3 FAs, and evidence on parenteral supplementation was insufficient. In critical care, enteral supplementation of n-3 FAs had beneficial effects on clinical outcomes; evidence on parenteral supplementation in critical care was inconsistent. The incorporation of n-3 FAs in plasma and blood cells was slower with enteral supplementation (4-7 d) than with parenteral supplementation (1-3 d). The washout was 5-7 d.

CONCLUSIONS

This review shows the beneficial effects of n-3 FA supplementation in cancer, surgical oncology, and critical care patients. Supplementation in these specific patient populations could be considered with the route of administration taken into account.

Preoperative short-term parenteral administration of polyunsaturated fatty acids ameliorates intestinal inflammation and postoperative ileus in rodents

PURPOSE

Abdominal surgery results in an inflammation of the intestinal muscularis externa (ME), subsequently leading to postoperative ileus (POI). Polyunsaturated fatty acids (PUFA) are known to modulate inflammation. The aim of this study was to analyze the effect of preoperative parenteral administration of marine (n-3) or soybean (n-6) PUFA lipid emulsions (PUFA-LE) on POI and tissue fatty acid profiles.

METHODS

Rodents underwent intestinal manipulation (IM) after 5 days of parenteral administration of 10-mL/kg body weight saline, (n-3), or (n-6) PUFA-LE. Sham animals received saline treatment without IM. In rats, postoperative inflammation was quantified by ME neutrophil levels and NO production in organ culture, and ME function was determined by an in vitro contractility measurement. Additionally, in vivo gastrointestinal transit (GIT) was analyzed in mice. Lipopolysaccharide-induced IL-6 expression of rat bone marrow-derived mononuclear cells and ME was analyzed. Fatty acids were measured by gas chromatography in rat blood, bone marrow cells, and ME.

RESULTS

The (n-3) PUFA-LE reduced neutrophil levels and NO production after IM and improved in vitro jejunal contractility and GIT time. The (n-6) PUFA-LE significantly reduced postoperative inflammation and tended to improve intestinal motility (P < 0.06). Interestingly, (n-6) PUFA-LE significantly reduced the levels of arachidonic acid in ME (-63%), while (n-3) PUFA-LE reduced arachidonic acid (-20%) and additionally raised EPA (+550%).

CONCLUSION

Short-term preoperative parenteral administration of (n-3) or (n-6) PUFA-LE significantly alters tissue-specific fatty acid profiles. Preoperative parenteral PUFA-LE supplementation, preferably by marine (n-3) PUFA, ameliorates postoperative intestinal inflammation and dysmotility and could be a promising therapeutic option in POI prophylaxis.

Effect of intravenous omega-3 fatty acid infusion and hemodialysis on fatty acid composition of free fatty acids and phospholipids in patients with end-stage renal disease

BACKGROUND

Patients treated with hemodialysis (HD) have been reported to have decreased levels of ω-3 polyunsaturated fatty acids (PUFAs) in plasma and cells. The aim of this study was to investigate the effect of ω-3 PUFAs administered intravenously during HD, as well as the effect of HD treatment, on the fatty acid composition of plasma free fatty acids (FFAs), plasma phospholipids, and platelet phospholipids.

METHODS

Forty-four HD patients were randomized to groups receiving either a single dose of a lipid emulsion containing 4.1 g of ω-3 PUFAs or placebo (saline) administered intravenously during HD. Blood was drawn immediately before (baseline) and after (4 hours) HD and before the next HD session (48 hours). Fatty acid composition was measured using gas chromatography.

RESULTS

The increase in ω-3 FFAs was greater in the ω-3 PUFA group compared with the placebo group, whereas the increase in total FFAs was similar between the 2 groups. In the ω-3 PUFA group, ω-3 PUFAs in plasma phospholipids were higher after 48 hours than at baseline, and in platelet phospholipids, ω-3 PUFAs increased after 4 hours. In the placebo group, no changes were observed in ω-3 PUFAs in plasma and platelet phospholipids.

CONCLUSIONS

Intravenous ω-3 PUFAs administered during HD caused a transient selective increase in ω-3 FFA concentration. Furthermore, ω-3 PUFAs were rapidly incorporated into platelets, and the content of ω-3 PUFAs in plasma phospholipids increased after 48 hours.

Fish oil supplementation alters levels of lipid mediators of inflammation in microenvironment of acute human wounds

Chronic wounds often result from prolonged inflammation involving excessive polymorphonuclear leukocyte activity. Studies show that the ω-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in fish oils generate bioactive lipid mediators that reduce inflammation and polymorphonuclear leukocyte recruitment in numerous inflammatory disease models. This study's purpose was to test the hypotheses that boosting plasma levels of EPA and DHA with oral supplementation would alter lipid mediator levels in acute wound microenvironments and reduce polymorphonuclear leukocyte levels. Eighteen individuals were randomized to 28 days of either EPA+DHA supplementation (Active Group) or placebo. After 28 days, the Active Group had significantly higher plasma levels of EPA (p<0.001) and DHA (p<0.001) than the Placebo Group and significantly lower wound fluid levels of two 15-lipoxygenase products of ω-6 polyunsaturated fatty acids (9-hydroxyoctadecadienoic acid [p=0.033] and 15-hydroxyeicosatrienoic acid [p=0.006]), at 24 hours postwounding. The Active Group also had lower mean levels of myeloperoxidase, a leukocyte marker, at 12 hours and significantly more reepithelialization on Day 5 postwounding. We suggest that lipid mediator profiles can be manipulated by altering polyunsaturated fatty acid intake to create a wound microenvironment more conducive to healing.

Perspectives on the use of marine and freshwater hydrobiont oils for development of drug delivery systems

Marine foods represent a unique source of poly-unsaturated fatty acids (PUFA) of the omega-3 (n-3) family. Today it is generally accepted that fish oil is important in a healthy and balanced omnivorous human diet. This favorable health perception of fish oil is however troubled by the high level of PUFA oxidation and low absorption in the gastro-intestinal tract. In this work we present and described various types of delivery systems which are used to improve PUFA and fish oil availability and oxidative stability.

Innate immunity signaling pathways: links between immunonutrition and responses to sepsis

Septic infections in patients treated in intensive care units show the highest mortality rates. Despite advances in treatment methods, there is still no therapy available to efficiently reduce the excessive inflammatory response, which can increase the risk of multiple organ failure. One of the ways to discover new, more efficient treatment methods involves regulating the mechanisms of inflammatory response to a massive infection. Toll-like receptors (TLRs) that recognize pathogen-associated molecular patterns play a significant role in innate antibacterial and inflammatory responses. The regulatory impact of immunonutrition on TLR expression in septic patients seems to be a promising research direction. This paper presents the main mechanisms for the innate immune response to lipopolysaccharide, based on the research results for both TLR-dependent and independent signaling pathways. Special emphasis was put on the research results for the TLR-dependent immune response and the anti-bacterial/anti-inflammatory response after applying immunonutrition with increased concentrations of glutamine and unsaturated fatty acids.

Effects of short-term infusion of lipid emulsions on pro-inflammatory cytokines and lymphocyte apoptosis in septic and non-septic rats

Long-term administration of PUFA is known to modulate immune functions and apoptotic pathways depending on the respective amount of n-6 and n-3 fatty acids (FA). Data on short-term effects on apoptotic pathways are rare. Apoptosis of splenic lymphocytes is the hallmark of detrimental sepsis. Therefore, we aimed to compare the immediate effects of parenterally administered n-6-enriched soyabean oil (SO)- and n-3-enriched fish oil (FO)-based lipid emulsions after laparotomy (LAP; sham procedure) and after induction of acute, severe sepsis by caecal ligation and incision. After 390 min of observation time, plasma was analysed for IL-1β, IL-6 and NEFA. Apoptosis in splenic lymphocytes was quantified by Annexin-V expression. After LAP, infusion of both FO and SO did not change cytokine concentrations. Sepsis increased both cytokines. FO but not SO further augmented the rise. After LAP, SO increased NEFA, and both lipid emulsions reduced free arachidonic acid (AA). Sepsis resulted in a dramatic decrease in NEFA and AA. The drop in NEFA and AA was prevented by both SO and FO. In addition, FO resulted in an increased concentration of n-3 FA under both conditions. Infusion of both lipid emulsions induced apoptosis in splenic lymphocytes after LAP. Sepsis-induced apoptosis was not further enhanced by FO or SO. The present study shows that short-term administration of FO as opposed to SO caused pro-inflammatory effects during sepsis. Moreover, short-term administration of both SO and FO suffices to induce apoptosis in splenic lymphocytes. Finally, SO and FO do not further enhance sepsis-induced splenic apoptosis.

Early fish oil supplementation and organ failure in patients with septic shock from abdominal infections: a propensity-matched cohort study

BACKGROUND

Fish oil (FO) has immunomodulating effects and may improve organ function and outcome in critically ill patients. This retrospective, propensity-matched cohort study investigates the effects of early intravenous FO supplementation on organ failure in patients with septic shock from abdominal infection.

METHODS

A medical database was retrospectively searched for critically ill patients admitted because of septic shock from abdominal infection (n = 194). Demographic, clinical, and laboratory data; FO supplementation (10 g/d) (n = 42); rate, degree, and number of organ failures assessed by the Sequential Organ Failure Assessment (SOFA) score; and secondary outcome variables were recorded. A propensity score-based model was used to establish 2 comparable groups (FO, n = 29; control, n = 29). Mann-Whitney rank sum test, Fisher exact test, and logistic regression analyses were used to compare variables between groups.

RESULTS

There were no differences in the rate of single organ failures, the maximum SOFA score (median [interquartile range (IQR)], 12 [8-15] vs 11 [9-14]; P = .99), or the number of organ failures (median [IQR], 2 [1-3] vs 2 [1-3]; P = .54] between patients receiving FO supplementation and those not receiving supplementation. There were no group differences in the maximum C-reactive protein levels (P = .1), duration of mechanical ventilation (P = .65) or hemofiltration (P = .21), intensive care unit-acquired infections, intensive care unit length of stay (P = .59), and intensive care unit (P = 1) or hospital mortality (P = 1).

CONCLUSIONS

Early intravenous FO may not decrease the number and degree of organ failures in patients with septic shock from abdominal infection. Future trials are needed before FO supplementation in septic shock from abdominal infection can be recommended.

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.

Fish oil in critical illness: mechanisms and clinical applications

Fish oil is rich in omega-3 fatty acids, which have been shown to be beneficial in multiple disease states that involve an inflammatory process. It is now hypothesized that omega-3 fatty acids may decrease the inflammatory response and be beneficial in critical illness. After a review of the mechanisms of omega-3 fatty acids in inflammation, research using enteral nutrition formulas and parenteral nutrition lipid emulsions fortified with fish oil were examined. The results of this research to date are inconclusive for both enteral and parenteral omega-3 fatty acid administration. More research is required before definitive recommendations can be made on fish oil supplementation in critical illness.

Omega-3 fatty acids in critical illness

Supplementation of enteral nutritional formulas and parenteral nutrition lipid emulsions with omega-3 fatty acids is a recent area of research in patients with critical illness. It is hypothesized that omega-3 fatty acids may help reduce inflammation in critically ill patients, particularly those with sepsis and acute lung injury. The objective of this article is to review the data on supplementing omega-3 fatty acids during critical illness; enteral and parenteral supplemental nutrition are reviewed separately. The results of the research available to date are contradictory for both enteral and parenteral omega-3 fatty acid administration. Supplementation with omega-3 fatty acids may influence the acute inflammatory response in critically ill patients, but more research is needed before definitive recommendations about the routine use of omega-3 fatty acids in caring for critically ill patients can be made.

The pleiotropic effects of statins and omega-3 fatty acids against sepsis: a new perspective

The available therapeutic options for sepsis are restricted by their effectiveness and high cost. Emerging preliminary data suggest that statins and omega-3 fatty acids (OM3FA) may be associated with improved outcomes in terms of prevention and treatment of sepsis. We sought to review the current evidence on the effectiveness of their combined administration against sepsis, by carrying out a review of PubMed and Scopus databases for relevant studies, without imposing language or time restrictions. No clinical studies were identified regarding the effect of the combination treatment with statins and OM3FA on sepsis in terms of prevention or treatment. However, there is experimental evidence that both statins and OM3FA inhibit the inflammatory process at different levels, but also enhance inhibition at those levels that are common. There are also preliminary data supporting the beneficial effect of this combination on platelet function and other haemostatic mechanisms. Appropriately designed and powered clinical trials are warranted to investigate the effectiveness and safety of the combined administration of statins and OM3FA for the prevention and treatment of sepsis.

Randomized clinical trial of intravenous soybean oil alone versus soybean oil plus fish oil emulsion after gastrointestinal cancer surgery

BACKGROUND

Specific immunonutrients may reduce the incidence of postoperative complications and shorten recovery time. This randomized trial evaluated the clinical efficacy of a fish oil emulsion on outcome and immune function after gastrointestinal cancer surgery.

METHODS

A total of 206 patients with gastrointestinal or colonic cancer were randomized to receive isocaloric and isonitrogenous intravenous infusions of either soybean oil alone (1.2 g per kg bodyweight per day; control group, 103 analysed) or soybean plus fish oil emulsion (1.0 and 0.2 g per kg per day respectively; treatment group, 100 analysed) over 20-24 h daily for 7 days after surgery.

RESULTS

Baseline data were comparable in the two groups. There were fewer infectious complications (four versus 12 on day 8; P = 0.066), systemic inflammatory response syndrome (SIRS) was significantly less common (four versus 13; P = 0.039) and hospital stay was significantly shorter (mean(s.d.) 15(5) versus 17(8) days; P = 0.041) in the treatment group. Total postoperative medical costs were comparable in the two groups (mean(s.d.) US $ 1269(254) and 1302(324) in treatment and control groups respectively; P = 0.424). The median (interquartile range) difference in CD4/CD8 between days 1 and 8 after surgery was + 0.30 (0.06 to 0.79) in patients receiving fish oil and + 0.20 (-0.19 to 0.55) in controls (P = 0.021). No severe adverse events occurred in either group.

CONCLUSION

Fish oil emulsion-supplemented parenteral nutrition significantly reduced SIRS and length of hospital stay. These clinical benefits may be related to normalization of cellular immune functions and modulation of the inflammatory response.

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 randomised study on the clinical progress of high-risk elective major gastrointestinal surgery patients treated with olive oil-based parenteral nutrition with or without a fish oil supplement

n-3 Fatty acids have clinical benefits. The primary aim of the present study was the assessment of infection in patients who underwent major high-risk elective gastrointestinal surgery receiving postoperatively fish oil (FO)-supplemented parenteral nutrition (PN), compared with those receiving a standard olive oil (OO) emulsion. The secondary aims were the assessment of anti-inflammatory response and evaluation of tolerance and safety of these emulsions. A prospective, randomised, double-blind study was performed in patients requiring at least 5 d of PN. An isoenergetic and isoproteic formula was administered: group A received OO alone, while group B received OO that was partially replaced with FO (16.6 %, w/w). End points were outcome measures (mortality, sepsis, infection, hospitalisation days and PN duration), inflammatory response (C-reactive protein (CRP), prealbumin and leucocytes) and safety (TAG and glucose metabolism, and liver and kidney function). Statistical analysis was done using Student's t test and Fisher's exact test (P < 0.05). Twenty-seven patients were evaluated, with thirteen patients receiving FO. In this group, a significantly lower incidence of infections was found (23.1 v. 78.6 %, P = 0.007). CRP, prealbumin and leucocytes were not significantly different between the groups. There were no differences in safety parameters. We conclude that high-risk surgical patients receiving FO-supplemented PN for 5 d present a lower incidence of infection. Emulsions were safe and well tolerated.

Fatty acids and immune function: relevance to inflammatory bowel diseases

Fatty acids may influence immune function through a variety of mechanisms; many of these are associated with changes in fatty acid composition of immune cell membranes. Eicosanoids produced from arachidonic acid have roles in inflammation and immunity. Increased membrane content of n-3 fatty acids results in a changed pattern of production of eicosanoids, resolvins, and cytokines. Changing the fatty acid composition of immune cells also affects T cell reactivity and antigen presentation. Little attention has been paid to the influence of fatty acids on the gut-associated lymphoid tissue. However, there has been considerable interest in fatty acids and gut inflammation.

Impact of lipid emulsion containing fish oil on outcomes of surgical patients: systematic review of randomized controlled trials from Europe and Asia

OBJECTIVE

This study aimed to systematically review the clinical efficacy of lipid emulsion containing fish oil in surgical patients.

METHODS

Medline, SCI, Embase, Cochrane Library, and Chinese Biomedicine Database were searched for studies published before January 1, 2009 that were randomized controlled trials for postoperative patients. Parenteral nutrition with or without fish oil emulsion was the only difference between the intervention and control groups. Methodologic quality assessment was based on the Cochrane Handbook for Systematic Reviews of Interventions Version 5.0.1 and Jadad's score scale. RevMan 5.0 statistical software was used for meta-analysis.

RESULTS

Six trials met all inclusion criteria and were enrolled for final meta-analysis. The aggregated results of the trails showed that fish oil was associated with no mortality advantage. There was a significant reduction in infectious complications in patients receiving fish oil (relative risk 0.49, 95% confidence interval 0.26-0.93, P=0.03). The result on length of hospital stay showed a trend of shortening by 3.06 d associated with receiving fish oil. However, the difference was not significant. When excluding one obviously heterogeneous study and aggregating the other three remaining studies, results showed significantly shortening of length of hospital stay associated with receiving fish oil. Fish oil also significantly shortened length of stay in the intensive care unit by 2.07 d.

CONCLUSION

The administration of lipid emulsion containing fish oil to patients undergoing elective major operations improves outcomes. The infectious complications are significantly fewer and length of hospitalization significantly shortened for patients treated with lipid emulsion containing fish oil. Further well-designed randomized controlled trials are needed to demonstrate the cost effectiveness of lipid emulsion containing fish oil to postoperative patients.

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.

Lipid emulsions in parenteral nutrition of intensive care patients: current thinking and future directions

Background

Energy deficit is a common and serious problem in intensive care units and is associated with increased rates of complications, length of stay, and mortality. Parenteral nutrition (PN), either alone or in combination with enteral nutrition, can improve nutrient delivery to critically ill patients. Lipids provide a key source of calories within PN formulations, preventing or correcting energy deficits and improving outcomes.

Discussion

In this article, we review the role of parenteral lipid emulsions (LEs) in the management of critically ill patients and highlight important biologic activities associated with lipids. Soybean-oil-based LEs with high contents of polyunsaturated fatty acids (PUFA) were the first widely used formulations in the intensive care setting. However, they may be associated with increased rates of infection and lipid peroxidation, which can exacerbate oxidative stress. More recently developed parenteral LEs employ partial substitution of soybean oil with oils providing medium-chain triglycerides, ω-9 monounsaturated fatty acids or ω-3 PUFA. Many of these LEs have demonstrated reduced effects on oxidative stress, immune responses, and inflammation. However, the effects of these LEs on clinical outcomes have not been extensively evaluated.

Conclusions

Ongoing research using adequately designed and well-controlled studies that characterize the biologic properties of LEs should assist clinicians in selecting LEs within the critical care setting. Prescription of PN containing LEs should be based on available clinical data, while considering the individual patient’s physiologic profile and therapeutic requirements.

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.