Enteral nutrition with eicosapentaenoic acid, gamma-linolenic acid, and antioxidants reduces alveolar inflammatory mediators and protein influx in patients with acute respiratory distress syndrome

Efficacy of dietary supplements on mortality and clinical outcomes in adults with sepsis and septic shock: A systematic review and network meta-analysis

AIM

The aim of this network meta-analysis (NMA) was to investigate the effects of different dietary supplements on the mortality and clinical status of adults with sepsis.

METHODS

We searched PubMed, EMBASE, and the Cochrane Library Central Register of Controlled Trials until February 2023. The inclusion criteria were: 1) randomized controlled trials (RCT)s; 2) adults suffering sepsis or septic shock; 3) evaluation of short- or long-mortality; and 4) publications between 1994 and 2023. The general information of studies and details of interventions were extracted. The primary outcome was short-term mortality (<90 days), and the secondary outcomes were long-term mortality (≥90 days), length of ICU and hospital stays, and duration of mechanical ventilation (MV). The risk of bias of RCTs was assessed using the Cochrane risk of bias tool 2 (ROB2). A random effect NMA was performed to rank the effect of each intervention using a frequentist approach.

RESULTS

Finally, 56 RCTs with 5957 participants met the criteria. Approximately, one-third of RCTs were low risk of bias. NMA analysis revealed that there was no treatment more effective in short- or long-term mortality than control or other interventions, except for magnesium (RR: 0.33, 95% CI: 0.14, 0.79; GRADE = low) and vitamin C (RR: 0.81, 95% CI: 0.67, 0.99; low certainty evidence), which had beneficial effects on short-term mortality. Moreover, eicosapentaenoic acid, gamma-linolenic acid, and antioxidants (EPA + GLA + AOs) combination was the most effective, and magnesium, vitamin D and vitamin C were the other effective approaches in terms of duration of MV, and ICU length of stay. There was no beneficial dietary supplement for hospital stay in these patients.

CONCLUSIONS

In septic patients, none of the dietary supplements had a substantial effect on mortality except for magnesium and vitamin C, which were linked to lower short-term mortality with low certainty of evidence. Further investigation into high-quality studies with the use of dietary supplements for sepsis should be highly discouraged.

The role of low-carbohydrate diets in the intensive care unit

Low-carbohydrate, high-fat (LCHF) nutrition therapy is characterized by carbohydrates comprising <26% of the daily caloric intake and a higher proportion of fat. LCHF therapies reduce exogenous glucose load, improve glycemic control, decrease inflammation, and improve clinical outcomes such as respiratory function. Given the altered metabolism in critically ill patients, LCHF nutrition therapy may be especially beneficial as it enables the conservation of protein and glucose for metabolic roles beyond energy use. In critical illness, LCHF diets have the potential to reduce hyperglycemia, improve ventilation, decrease hospital length of stay and reduce hospital costs. The purpose of this commentary piece is to describe LCHF nutrition therapy, summarize its impact on health outcomes, and discuss its role in the intensive care unit (ICU). Additional research on the effects of LCHF nutrition therapy on critically ill patients is warranted, including a focus on COVID-19.

The effect of perioperative immunonutrition on patients undergoing esophagectomy: a systematic review and updated meta-analysis

Introduction

Background: immunonutrition has been introduced and proposed to have positive modulating effects on inflammatory and immune responses in surgical patients. This meta-analysis aimed to assess whether perioperative enteral immunonutrition (EIN) can reduce postoperative complications or reduce inflammatory responses in esophageal cancer (EC) patients undergoing esophagectomy. Methods: PubMed, Embase, Web of science, EBSCO, and Cochrane library databases were systematically searched. Randomized controlled trials (RCTs) assessing the effect of EIN before and/or after surgery in EC patients undergoing esophagectomy were identified. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. Results: ten RCTs involving 1,052 patients were included in the meta-analysis, including 573 patients in the EIN group and 479 patients in the enteral nutrition (EN) group. Overall, no significant difference was observed between the two groups in the incidence of postoperative pneumonia, surgical site infection, intra-abdominal abscess, septicemia, and urinary tract infection. No significant incidence of postoperative anastomotic leakage, acute respiratory distress syndrome (ARDS), and in-hospital mortality was found. Conclusions: perioperative enteral immunonutrition did not reduce the incidence of infectious complications and anastomotic leakage in EC patients undergoing esophagectomy, nor did it reduce postoperative CRP and IL-6, but did not increase in-hospital mortality.

Metabolic Support in Acute Respiratory Distress Syndrome: A Narrative Review

Nutritional support for acute respiratory distress syndrome (ARDS) patients shares metabolic notions common to other critically ill conditions. Nevertheless, it generates specific concern regarding the primary limitation of oxygen supply and the complications of carbon dioxide elimination, as well as the significant metabolic alterations due to the body's response to illness. In the present narrative review, after briefly summarizing the pathophysiology of critical illness stress response and patients' metabolic requirements, we focus on describing the characteristics of metabolic and artificial nutrition in patients with acute respiratory failure. In patients with ARDS, several aspects of metabolism assume special importance. The physiological effects of substrate metabolism are described for this setting, particularly regarding energy consumption, diet-induced thermogenesis, and the price of their clearance, transformation, and storage. Moreover, we review the possible direct effects of macronutrients on lung tissue viability during ARDS. Finally, we summarize the noteworthy characteristics of metabolic control in critically ill patients with ARDS and offer a suggestion as to the ideal methods of metabolic support for this problem.

Could early infusion of fish-oil-based lipid emulsion affect the need for intensive care in moderately diseased COVID-19 patients? A randomized clinical trial

Background

Sixty moderate diseased COVID-19 patients were divided into two equal groups and were enrolled in a randomized double-blind clinical trial. Group C was delivered standard enteral nutrition plus 100 ml/day of 0.9% normal saline. Group L was delivered fish-oil-based lipid emulsion (FOBLE) supplementation to standard enteral nutrition at a dose of 100 ml/day. Both groups infused at a rate of 12.5 ml/h over 8 h for 5 days. We aimed to compare the effect of FOBLE versus placebo in COVID-19 disease to clarify the impact on the number of patients shifted to the ICU, oxygenation, inflammatory markers, and short-term outcomes (7 days).

Results

The failed conventional care and shift to ICU was significantly lower in group L in comparison to group C (six patients (20.0%) versus 14 patients (46.7%) shifted to ICU, P-value = 0.028). The inflammatory markers were determined and evaluated. Throughout the trial, there were no significant changes with the exception of the 7th day neutrophil/lymphocyte ratio (NLR), when the ratio was lower in group L than in group C (6.10 (3.90–7.20) versus 9.65 (8.30–10.90), respectively, P-value 0.001).

Conclusions

In moderate diseased COVID-19 patients, early administration of parenteral FOBLE as an adjuvant to enteral feeding reduces shifts and so minimizes the burden on the ICU.

Trial registration

ClinicalTrials.gov PRS (NCT04957940). Registered on 5 July 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42077-022-00251-0.

The effect of wheat germ-enriched enteral formula on clinical and anthropometric factors in mechanically ventilated patients admitted to the intensive care unit

BACKGROUND & AIMS

Nutritional support is considered as an important therapeutic strategy among critically ill patients. To evaluate the effect of a wheat germ-enriched formula in patients admitted to the intensive care unit (ICU).

METHODS

This randomized controlled clinical trial study was conducted on 100 patients admitted to the ICU. Patients randomly received a wheat germ-enriched formula or a standard formula from the first day of admission until weaning from the ventilator. Then, the duration of mechanical ventilation, the length of ICU, hospital admission, body composition and mortality rate were compared between the two groups.

RESULTS

Based on the results, wheat germ-enriched formula caused a significant reduction in the length of mechanical ventilation (29.80 ± 21.99 days vs. 36.48 ± 8.78 days, P < 0.001), the ICU length of stay (32.92 ± 21.04 days vs. 37.70 ± 8.76, P < 0.001), and the SOFA score (4.60 ± 1.28 vs. 5.68 ± 1.25, P < 0.001) compared to the control group. However, the intervention group demonstrated a significant increase in the basal metabolic rate, mid upper arm circumference, skeletal muscle mass, body cell mass, and GCS score compared to the control group (P < 0.05). Finally, no significant difference was observed between the two groups in terms of the hospital length of stay, ICU mortality, and body fat percentage (P > 0.05).

CONCLUSION

In general, wheat germ enriched formula may exert beneficial effect on clinical and anthropomorphic variables in patients admitted to the ICU.

TRIAL REGISTRATION

The study was approved by the Ethics Committee of the Urmia University of Medical Sciences under number IR.umsu.rec.1396.88 and registered at the Iranian Registry of Clinical Trials Website as IRCT20171221037983N3.

Effect of enteral immunomodulatory nutrition formula on mortality and critical care parameters in critically ill patients: A systematic review with meta-analysis

BACKGROUND

Enteral immunomodulatory nutrition is recommended as an adjuvant therapy for patients in intensive care units (ICU), but its effectiveness is incompletely understood.

AIM

The aim of this review was to examine the effect of a commonly used immunomodulatory formula-omega-3 fatty acids, γ-linolenic acid, and antioxidants-on clinical outcomes and mortality risk in critically ill patients.

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs).

METHOD

PubMed, Scopus, and Institute for Scientific Information (ISI) Web of Knowledge databases were searched until 18 February 2021. RCTs that used the immunomodulatory formula in the ICU were included.

RESULTS

Ten RCTs (1166 participants) were included in the meta-analysis. The immunomodulatory formula reduced the duration of ICU stay weighted mean difference [(WMD): -2.97 days; 95%CI: -5.59, -0.35)], mechanical ventilation (WMD = -2.20 days, 95%CI: -4.29, -0.10), sequential organ failure assessment and multiple organ dysfunction scores (Hedge's g: -0.42 U/L; 95% CI: -0.74, -0.11), decreased 8-day overall mortality risk (RR = 0.74, 95% CI: 0.58, 0.91), and extended the ICU-free days (WMD: 4.06 days, 95% CI: 0.02, 8.09). The improvement in respiratory function and reduction in mortality risk was more in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Furthermore, the reduction in mechanical ventilation and mortality risk was more evident in older (>60 years) vs young adults.

CONCLUSION AND RELEVANCE TO CLINICAL PRACTICE

Taken together, the immunomodulatory formula may enhance clinical practice for critical care nurses, such that the prevalence and/or susceptibility to secondary conditions commonly encountered in the ICU (ie, ALI and ARDS) could be attenuated, ultimately allowing critical care nurses to focus their care on the primary reason for which a patient is in the ICU. The study protocol was registered in PROSPERO.

Enteral nutrition modulation with n-3 PUFAs directs microbiome and lipid metabolism in mice

Nutritional support using exclusive enteral nutrition (EEN) has been studied as primary therapy for the management of liver diseases, Crohn’s disease, and cancers. EEN can also increase the number of beneficial microbiotas in the gut, improve bile acid and lipid metabolism, and decrease the number of harmful dietary micro-particles, possibly by influencing disease occurrence and increasing immunity. This study investigated the effects of EEN-n-3 polyunsaturated fatty acids (3PUFAs) (EEN-3PUFAs) on the gut microbiome, intestinal barrier, and lipid or bile acid metabolism in mice. Metagenomic sequencing technology was used to analyze the effects of EEN-3PUFAs on the composition of gut microbiome signatures. The contents of short-chain fatty acids (SCFAs) and bile acids in the feces and liver of the mice were assayed by gas chromatography and ultra-high-pressure liquid chromatography/high-resolution tandem mass spectrometry, respectively. The levels of lipopolysaccharide (LPS) and D-lactic acid in the blood were used to assess intestinal permeability. The results indicated that EEN-3PUFAs could improve the composition of gut microbiome signatures and increase the abundance of Barnesiella and Lactobacillus (genus), Porphyromonadaceae, and Bacteroidia (species), and Bacteroidetes (phylum) after EEN-3PUFAs initiation. In addition, EEN-3PUFAs induced the formation of SCFAs (mainly including acetic acid, propionic acid, and butyric acid) and increased the intestinal wall compared to the control group. In conclusion, EEN-3PUFAs modulate the alterations in gut microbiome signatures, enhanced intestinal barrier, and regulated the fatty acid composition and lipid metabolism shifts and the putative mechanisms underlying these effects.

Dietary Fish, Fish Nutrients, and Immune Function: A Review

Dietary habits have a major impact on the development and function of the immune system. This impact is mediated both by the intrinsic nutritional and biochemical qualities of the diet, and by its influence on the intestinal microbiota. Fish as a food is rich in compounds with immunoregulatory properties, among them omega-3 fatty acids, melatonin, tryptophan, taurine and polyamines. In addition, regular fish consumption favors the proliferation of beneficial members of the intestinal microbiota, like short-chain fatty acid-producing bacteria. By substituting arachidonic acid in the eicosanoid biosynthesis pathway, long-chain omega-3 fatty acids from fish change the type of prostaglandins, leukotrienes and thromboxanes being produced, resulting in anti-inflammatory properties. Further, they also are substrates for the production of specialized pro-resolving mediators (SPMs) (resolvins, protectins, and maresins), lipid compounds that constitute the physiological feedback signal to stop inflammation and give way to tissue reparation. Evidence from human observational and interventional studies shows that regular fish consumption is associated with reduced incidence of chronic inflammatory conditions like rheumatoid arthritis, and that continuous infusion of fish oil to tube-fed, critically ill patients may improve important outcomes in the ICU. There is also evidence from animal models showing that larger systemic concentrations of omega-3 fatty acids may counter the pathophysiological cascade that leads to psoriasis. The knowledge gained over the last few decades merits future exploration of the potential role of fish and its components in other conditions characterized by deregulated activation of immune cells and a cytokine storm like viral sepsis or COVID-19.

In-silico drug repurposing study predicts the combination of pirfenidone and melatonin as a promising candidate therapy to reduce SARS-CoV-2 infection progression and respiratory distress caused by cytokine storm

From January 2020, COVID-19 is spreading around the world producing serious respiratory symptoms in infected patients that in some cases can be complicated by the severe acute respiratory syndrome, sepsis and septic shock, multiorgan failure, including acute kidney injury and cardiac injury. Cost and time efficient approaches to reduce the burthen of the disease are needed. To find potential COVID-19 treatments among the whole arsenal of existing drugs, we combined system biology and artificial intelligence-based approaches. The drug combination of pirfenidone and melatonin has been identified as a candidate treatment that may contribute to reduce the virus infection. Starting from different drug targets the effect of the drugs converges on human proteins with a known role in SARS-CoV-2 infection cycle. Simultaneously, GUILDify v2.0 web server has been used as an alternative method to corroborate the effect of pirfenidone and melatonin against the infection of SARS-CoV-2. We have also predicted a potential therapeutic effect of the drug combination over the respiratory associated pathology, thus tackling at the same time two important issues in COVID-19. These evidences, together with the fact that from a medical point of view both drugs are considered safe and can be combined with the current standard of care treatments for COVID-19 makes this combination very attractive for treating patients at stage II, non-severe symptomatic patients with the presence of virus and those patients who are at risk of developing severe pulmonary complications.

Impact of rs174537 on Critically Ill Patients with Acute Lung Injury: A Secondary Analysis of the OMEGA Randomized Clinical Trial

BACKGROUND

Nutrition in the intensive care unit is vital for patient care; however, immunomodulatory diets rich in PUFAs like γ-linolenic acid (GLA), EPA, and DHA remain controversial for patients with acute respiratory distress syndrome. We postulate that genetic variants impacting PUFA metabolism contribute to mixed responses to PUFA-rich diets.

OBJECTIVES

In this study, we aimed to test the effects of single nucleotide polymorphism (SNP) rs174537 on differential responses to PUFA-rich diets.

METHODS

We performed a secondary analysis of the OMEGA trial (NCT00609180) where 129 subjects received placebo control diets and 143 received omega-oil. DNA was extracted from buffy coats and used to genotype rs174537; plasma was used to quantitate PUFAs. We tested for SNP-diet interactions on PUFA concentrations, inflammatory biomarkers, and patient outcomes.

RESULTS

We observed that all individuals receiving omega-oil displayed significantly higher concentrations of GLA, EPA, and DHA (all P < 0.0001), but they did not vary by genotype at rs174537. Statistically significant SNP-diet interactions were observed on circulating DHA concentrations in African Americans. Specifically, African American T-allele carriers on placebo illustrated elevated DHA concentrations. Additionally, all individuals receiving omega-oil had higher concentrations of EPA-derived urinary F3-isoprostane (Caucasians: P = 0.0011; African Americans: P = 0.0002). Despite these findings, we did not detect any significant SNP-diet interactions on pulmonary functional metrics, clinical outcomes, and mortality.

CONCLUSIONS

This study highlights the importance of genetic and racial contributions to PUFA metabolism and inflammation. In particular, rs174537 had a significant impact on circulating DHA and urinary isoprostane concentrations. Given our relatively small sample size, further investigations in larger multiethnic cohorts are needed to evaluate the impact of rs174537 on fatty acid metabolism and downstream inflammation.

Evaluation of the Metabolic Effects of Hydrogen Sulfide on the Development of Bombyx mori (Lepidoptera: Bombycidae), Using Liquid Chromatography-Mass Spectrometry-Based Metabolomics

Hydrogen sulfide (H2S) is a highly poisonous gas with an unpleasant smell of rotten eggs. Previous studies of H2S have primarily focused on its effects on mammalian nervous and respiratory systems. In this study, silkworm developmental parameters and changes in metabolites in response to H2S exposure were investigated using a hemolymph metabolomic approach, based on liquid chromatography-mass spectrometry (LC-MS). The developmental parameters, body weight, cocoon weight, cocoon shell weight, and cocoon shell ratio, were noticeably increased following H2S exposure, with the greatest effects observed at 7.5-μM H2S. Metabolites upregulated under H2S exposure (7.5 μM) were related to inflammation, and included (6Z, 9Z, 12Z)-octadecatrienoic acid, choline phosphate, and malic acid, while hexadecanoic acid was downregulated. Identified metabolites were involved in biological processes, including pyrimidine, purine, and fatty acid metabolism, which are likely to affect silk gland function. These results demonstrate that H2S is beneficial to silkworm development and alters metabolic pathways related to spinning function and inflammation. The present study provides new information regarding the potential functions of H2S in insects and metabolic pathways related to this phenomenon.

Bronchoalveolar fluid and plasma inflammatory biomarkers in contemporary ARDS patients

Purpose: Bronchoalveolar fluid (BALF) and plasma biomarkers are often endpoints in early phase randomized trials (RCTs) in acute respiratory distress syndrome (ARDS). With ARDS mortality decreasing, we analyzed baseline biomarkers in samples from contemporary ARDS patients participating in a prior RCT and compared these to historical controls. Materials and methods: Ninety ARDS adult patients enrolled in the parent trial. BALF and blood were collected at baseline, day 4 ± 1, and day 8 ± 1. Interleukins-8/-6/-1β/-1 receptor antagonist/-10; granulocyte colony stimulating factor; monocyte chemotactic protein-1; tumour necrosis factor-α; surfactant protein-D; von Willebrand factor; leukotriene B₄; receptor for advanced glycosylation end products; soluble Fas ligand; and neutrophil counts were measured. Results: Compared to historical measurements, our values were generally substantially lower, despite our participants being similar to historical controls. For example, our BALF IL-8 and plasma IL-6 were notably lower than in a 1999 RCT of low tidal volume ventilation and a 2007 biomarker study, respectively. Conclusions: Baseline biomarker levels in current ARDS patients are substantially lower than 6-20 years before collection of these samples. These findings, whether from ICU care changes resulting in less inflammation or from variation in assay techniques over time, have important implications for design of future RCTs with biomarkers as endpoints.

Immunonutrition for acute respiratory distress syndrome (ARDS) in adults

BACKGROUND

Acute respiratory distress syndrome (ARDS) is an overwhelming systemic inflammatory process associated with significant morbidity and mortality. Pharmacotherapies that moderate inflammation in ARDS are lacking. Several trials have evaluated the effects of pharmaconutrients, given as part of a feeding formula or as a nutritional supplement, on clinical outcomes in critical illness and ARDS.

OBJECTIVES

To systematically review and critically appraise available evidence on the effects of immunonutrition compared to standard non-immunonutrition formula feeding on mechanically ventilated adults (aged 18 years or older) with acute respiratory distress syndrome (ARDS).

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL, conference proceedings, and trial registries for appropriate studies up to 25 April 2018. We checked the references from published studies and reviews on this topic for potentially eligible studies.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) and quasi-randomized controlled trials comparing immunonutrition versus a control or placebo nutritional formula in adults (aged 18 years or older) with ARDS, as defined by the Berlin definition of ARDS or, for older studies, by the American-European Consensus Criteria for both ARDS and acute lung injury.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the quality of studies and extracted data from the included trials. We sought additional information from study authors. We performed statistical analysis according to Cochrane methodological standards. Our primary outcome was all-cause mortality. Secondary outcomes included intensive care unit (ICU) length of stay, ventilator days, indices of oxygenation, cardiac adverse events, gastrointestinal adverse events, and total number of adverse events. We used GRADE to assess the quality of evidence for each outcome.

MAIN RESULTS

We identified 10 randomized controlled trials with 1015 participants. All studies compared an enteral formula or additional supplemental omega-3 fatty acids (i.e. eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA)), gamma-linolenic acid (GLA), and antioxidants. We assessed some of the included studies as having high risk of bias due to methodological shortcomings. Studies were heterogenous in nature and varied in several ways, including type and duration of interventions given, calorific targets, and reported outcomes. All studies reported mortality. For the primary outcome, study authors reported no differences in all-cause mortality (longest period reported) with the use of an immunonutrition enteral formula or additional supplements of omega-3 fatty acids and antioxidants (risk ratio (RR) 0.79, 95% confidence interval (CI) 0.59 to 1.07; participants = 1015; studies = 10; low-quality evidence).For secondary outcomes, we are uncertain whether immunonutrition with omega-3 fatty acids and antioxidants reduces ICU length of stay (mean difference (MD) -3.09 days. 95% CI -5.19 to -0.99; participants = 639; studies = 8; very low-quality evidence) and ventilator days (MD -2.24 days, 95% CI -3.77 to -0.71; participants = 581; studies = 7; very low-quality evidence). We are also uncertain whether omega-3 fatty acids and antioxidants improve oxygenation, defined as ratio of partial pressure of arterial oxygen (PaO₂) to fraction of inspired oxygen (FiO₂), at day 4 (MD 39 mmHg, 95% CI 10.75 to 67.02; participants = 676; studies = 8), or whether they increase adverse events such as cardiac events (RR 0.87, 95% CI 0.09 to 8.46; participants = 339; studies = 3; very low-quality evidence), gastrointestinal events (RR 1.11, 95% CI 0.71 to 1.75; participants = 427; studies = 4; very low-quality evidence), or total adverse events (RR 0.91, 95% CI 0.67 to 1.23; participants = 517; studies = 5; very low-quality evidence).

AUTHORS' CONCLUSIONS

This meta-analysis of 10 studies of varying quality examined effects of omega-3 fatty acids and/or antioxidants in adults with ARDS. This intervention may produce little or no difference in all-cause mortality between groups. We are uncertain whether immunonutrition with omega-3 fatty acids and antioxidants improves the duration of ventilator days and ICU length of stay or oxygenation at day 4 due to the very low quality of evidence. Adverse events associated with immunonutrition are also uncertain, as confidence intervals include the potential for increased cardiac, gastrointestinal, and total adverse events.

Immunonutrition in Critical Illness: What Is the Role?

Acute illness-associated malnutrition leads to muscle wasting, delayed wound healing, failure to wean from ventilator support, and possibly higher rates of infection and longer hospital stays unless appropriate metabolic support is provided in the form of nutrition therapy. Agreement is still lacking about the value of individual immune-modulating substrates for specific patient populations. However, it has long been agreed that there are 3 primary targets for these substrates: 1) mucosal barrier function, 2) cellular defense function, and 3) local and systemic inflammation. These targets guide the multitude of interventions necessary to stabilize and treat the hypercatabolic intensive care unit patient, including specialized nutrition therapy. The paradigm shift that occurred 30 years ago created a unique role for nutrition as an agent to support host defense mechanisms and prevent infectious complications in the critically ill patient. This overview of immunonutrition will discuss the evidence for its role in critical illness today.

Current evidence on ω-3 fatty acids in enteral nutrition in the critically ill: A systematic review and meta-analysis

Fish oil exerts anti-inflammatory and immunomodulatory properties that may be beneficial for critically ill patients, thus multiple randomized controlled trials and meta-analyses have been performed. However, controversy remains as to whether fish oil-enriched enteral nutrition can improve clinical outcomes in adult critically ill patients in intensive care units (ICUs). The aim of this study was to provide an up-to-date systematic review and meta-analysis of all randomized controlled trials of fish oil-containing enteral nutrition addressing relevant clinical outcomes in critically ill patients. A systematic literature search was conducted. The primary outcome was 28-d mortality. Secondary outcomes were ICU and hospital mortality, ICU and hospital length of stay (LOS), ventilation duration, and infectious complications. Predefined subgroup and sensitivity analyses were performed. Twenty-four trials, enrolling 3574 patients, met the inclusion criteria. The assessment of risk for bias showed that most of included studies were of moderate quality. The overall results revealed no significant effects of enteral fish oil supplementation on 28-d, ICU or hospital mortality. However, ICU LOS and ventilation duration were significantly reduced in patients receiving fish oil supplementation. Furthermore, subgroup analysis revealed a significant reduction in 28-d mortality, ICU LOS, and ventilation duration in patients with acute respiratory distress syndrome but not in other subgroups. When comparing high- and low-quality trials, significant reductions in 28-d mortality and ventilation duration in low-quality trials only were observed. Regarding ICU LOS a significant reduction was observed in high-quality trials; whereas only a trend was observed in low-quality trials. No significant effects on hospital LOS or infectious complications were observed in overall or subgroup analyses. Enteral fish oil supplementation cannot be recommended for critically ill patients, as strong scientific evidence for improved clinical benefits was not found. There is a signal of mortality benefit in patients with acute respiratory distress syndrome; however, results are based on low-quality studies. Further research should focus on the relation between the individual critically ill patients' immune response, the administration of fish oil, and clinical outcomes.

Gamma-linolenic acid ameliorated glycation-induced memory impairment in rats

CONTEXT

γ-Linolenic acid (GLA) is an important constituent of anti-ageing supplements.

OBJECTIVE

The current study investigates the anti-ageing effect of GLA in Sprague-Dawley rats.

MATERIALS AND METHODS

GLA (0.1, 0.2, 0.4, 2, 10, 20 and 24 μM) was initially evaluated for its effect on the formation of advanced glycation end products (AGEs) in vitro. For in vivo assessment (1, 5 or 15 mg/kg), the rat model of accelerated ageing was developed using d-fructose (1000 mg/kg (i.p.) plus 10% in drinking water for 40 days). Morris water maze was used to evaluate impairment in learning and memory. The blood of treated animals was used to measure glycosylated haemoglobin (HbA1c) levels. The interaction of GLA with active residues of receptor of AGE (RAGE) was analyzed using AutoDock Vina.

RESULTS

Our data showed that GLA inhibited the production of AGEs (IC₅₀ = 1.12 ± 0.05 μM). However, this effect was more significant at lower tested doses. A similar pattern was also observed in in vivo experiments, where the effect of fructose was reversed by GLA only at lowest tested dose of 1 mg/kg. The HbA1c levels also revealed significant reduction at lower doses (1 and 5 mg/kg). The in silico data exhibited promising interaction of GLA with active residues (Try72, Arg77 and Gln67) of RAGE.

CONCLUSION

The GLA, at lower doses, possesses therapeutic potential against glycation-induced memory decline.

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

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

Should Immune-Enhancing Formulations Be Used for Patients With Acute Respiratory Distress Syndrome?

The potential for regulating immune function in acute respiratory distress syndrome (ARDS) through enteral-administered anti-inflammatory lipids has generated much interest over the past 20 years. Yet recommendations remain inconclusive regarding the utilization of ω-3 fatty acids in patients with ARDS and acute lung injury (ALI). Studies are limited in number, with differing methods, small sample sizes, and conflicting results, making recommendations difficult to interpret.

Down-regulation of a signaling mediator in association with lowered plasma arachidonic acid levels in individuals with autism spectrum disorders

Previous studies have indicated that the altered composition of polyunsaturated fatty acids (PUFAs) might contribute to the pathophysiology of autism spectrum disorder (ASD). We examined the relationship between the plasma fatty acid levels, expressed as μg/ml, and the plasma levels of biomarkers of AA-related signaling mediators, such as ceruloplasmin, transferrin and superoxide dismutase, and assessed the behavioral symptoms of 30 individuals with ASD (mean age, 13.6 ± 4.3 years old) compared with 20 age- and gender-matched normal controls (mean age, 13.2 ± 5.4 years old) using Aberrant Behavior Checklists (ABC). The plasma levels of EPA and the plasma ratios of EPA/AA were significantly higher, while the plasma levels of AA and metabolites, such as 5,8,11,14-eicosatetraenoic acid, adrenic acid, and ceruloplasmin (Cp), were significantly lower in the 30 individuals with ASD compared with the 20 normal controls. The ABC scores were significantly increased in the ASD group compared with those of the control group. Thus, the results of the present study revealed that reduced plasma levels of AA and metabolites in association with high plasma EPA/AA ratios might down-regulate AA-related signaling mediators, such as Cp. Subsequently, reduced plasma Cp levels might reduce the protective capacity for brain damage, resulting in the pathophysiology underlying the behavioral symptoms in individuals with ASD. These findings suggest that reduced plasma AA levels may downregulate Cp.

High-dose Oral Ambroxol for Early Treatment of Pulmonary Acute Respiratory Distress Syndrome: an Exploratory, Randomized, Controlled Pilot Trial

OBJECTIVE

To evaluate efficacy of high-dose oral ambroxol in acute respiratory distress syndrome (ARDS) with respect to ventilator-free days (VFD).

DESIGN

Prospective, randomized, placebo-controlled, blinded pilot trial.

PATIENTS

Sixty-six mechanically ventilated patients (1 month to 12 years) with ARDS who were hand-ventilated for <24 hr before pediatric intensive care unit admission.

INTERVENTIONS

Patients randomized to oral ambroxol (40 mg/kg/day, in four divided doses) (n = 32) or placebo (n = 34) until 10 days, extubation or death whichever is earlier.

MEASUREMENTS AND MAIN RESULTS

Majority (91%) had pneumonia and bronchiolitis. Two study groups were similar in baseline characteristics. Mean partial pressure of arterial oxygen/fraction of inspired oxygen and oxygenation index were >175 and <10, respectively, with no difference in the two study groups. VFD were similar in the two study groups. Overall mortality was 26%. No adverse events were noted with ambroxol.

CONCLUSIONS

Among ventilated pulmonary ARDS patients with oxygenation index of <10, mortality was 26%. Ambroxol did not improve VFD. Study with higher and more frequently administered doses of ambroxol in larger sample is suggested after having generated relevant pharmacokinetic data among critically ill children.

Lipid emulsions for parenteral nutrition in critical illness

Critical illness is a life-threatening multisystem process that can result in significant morbidity and mortality. In most patients, critical illness is preceded by a physiological deterioration, characterized by a catabolic state and intense metabolic changes, resulting in malnutrition and impaired immune functions. In this context, parenteral lipid emulsions may modulate inflammatory and immune reactions, depending on their fatty acid composition. These effects appear to be based on complex modifications in the composition and structure of cell membranes, through eicosanoid and cytokine synthesis and by modulation of gene expression. The pathophysiological mechanisms underlying these fatty acid-induced immune function alterations in critical ill patients are however complex and partially understood. Indeed, despite a very abundant literature, experimental and clinical data remain contradictory. The optimization of lipid emulsion composition thus represents a major challenge for clinical medicine, to adequately modulate the inflammatory pathways. In the present review, we first address the metabolic response to aggression, the effects of parenteral lipid emulsions on inflammation and immunity, and finally the controversial place of these lipid emulsions during critical illness. The analysis furthermore highlights the pathophysiological mechanisms underlying the differential effects of lipid emulsions and their potential for improving the handling of critically ill patients.

Enteral Immunomodulatory Diet (Omega-3 Fatty Acid, γ-Linolenic Acid and Antioxidant Supplementation) for Acute Lung Injury and Acute Respiratory Distress Syndrome: An Updated Systematic Review and Meta-Analysis

Enteral immunomodulatory nutrition is considered as a promising therapy for the treatment of acute lung injury and acute respiratory distress syndrome (ALI/ARDS). However, there are still some divergences, and it is unclear whether this treatment should be recommended for patients with ALI/ARDS. Therefore, we conducted this systematic review and meta-analysis to assess the efficacy and safety of an enteral immunomodulatory diet on the clinical outcomes of ALI/ARDS patients. Methods: We retrieved potentially relevant clinical trials though electronic databases. All trials of enteral immunomodulatory diet for ALI/ARDS were included. Analyses of the overall all-cause mortality, 28-day ventilator-free days and 28-day intensive care unit (ICU) free days were conducted. Results: In total six controlled trials were evaluated. The pooled results did not show a significant reduction in the risk of all-cause mortality (M-H RR (the overall Mantel-Haenszel relative risk), 0.81 (95% CI, 0.50–1.31); p = 0.38; 6 trials, n = 717) in ALI/ARDS patients treated with the immunomodulatory diet. This treatment also did not extend the ventilator-free days and ICU-free days. However, patients with high mortality might benefit from this treatment. Conclusions: The enteral immunomodulatory diet could not reduce the severity of the patients with ALI/ARDS. Whereas, for ALI/ARDS patients with high mortality, this treatment might reduce the all-cause mortality, but its use should be treated with discretion.

Nonpulmonary treatments for pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

To describe the recommendations from the Pediatric Acute Lung Injury Consensus Conference on nonpulmonary treatments in pediatric acute respiratory distress syndrome.

DESIGN

Consensus conference of experts in pediatric acute lung injury.

METHODS

A panel of 27 experts met over the course of 2 years to develop a taxonomy to define pediatric acute respiratory distress syndrome and to make recommendations regarding treatment and research priorities. The nonpulmonary subgroup comprised three experts. When published data were lacking, a modified Delphi approach emphasizing strong professional agreement was utilized.

RESULTS

The Pediatric Acute Lung Injury Consensus Conference experts developed and voted on a total of 151 recommendations addressing the topics related to pediatric acute respiratory distress syndrome, 30 of which related to nonpulmonary treatment. All 30 recommendations had strong agreement. Patients with pediatric acute respiratory distress syndrome should receive 1) minimal yet effective targeted sedation to facilitate mechanical ventilation; 2) neuromuscular blockade, if sedation alone is inadequate to achieve effective mechanical ventilation; 3) a nutrition plan to facilitate their recovery, maintain their growth, and meet their metabolic needs; 4) goal-directed fluid management to maintain adequate intravascular volume, end-organ perfusion, and optimal delivery of oxygen; and 5) goal-directed RBC transfusion to maintain adequate oxygen delivery. Future clinical trials in pediatric acute respiratory distress syndrome should report sedation, neuromuscular blockade, nutrition, fluid management, and transfusion exposures to allow comparison across studies.

CONCLUSIONS

The Consensus Conference developed pediatric-specific definitions for pediatric acute respiratory distress syndrome and recommendations regarding treatment and future research priorities. These recommendations for nonpulmonary treatment in pediatric acute respiratory distress syndrome are intended to promote optimization and consistency of care for patients with pediatric acute respiratory distress syndrome and identify areas of uncertainty requiring further investigation.

The Effect of Omega-3 Fatty Acids on ARDS: A Randomized Double-Blind Study

PURPOSE

The aim of this study was to evaluate the effect of an enteral nutrition diet, enriched with omega-3 fatty acids because of its anti-inflammatory effects on treatment of patients with mild to moderate ARDS.

METHODS

This randomized clinical trial was performed in two ICUs of Tabriz University of Medical Sciences from Jun 2011 until Sep 2013 in north west of Iran. Fifty-eight patients with mild to moderate ARDS were enroled in this clinical trial. All patients received standard treatment for ARDS based on ARDS network trial. In intervention group, patients received 6 soft-gels of omega-3/day in addition to the standard treatment.

RESULTS

Tidal volume, PEEP, pH, PaO2/FiO2 , SaO2, P platue and PaCO2 on the 7(th) and 14(th) days didn't have significant difference between two groups. Indices of lung mechanics (Resistance, Compliance) had significant difference between the groups on the 14(th) day. Pao2 had significant difference between two groups on both 7(th) and 14(th) days. Trend of PaO2 changes during the study period in two groups were significant. We showed that adjusted mortality rate did not have significant difference between two groups.

CONCLUSION

It seems that adding omega-3 fatty acids to enteral diet of patients with ARDS has positive results in term of ventilator free days, oxygenation, lung mechanic indices; however, we need more multi center trials with large sample size and different doses of omega-3 fatty acids for their routine usage as an adjuant for ARDS treatment.

A Matter of Fat

Acute respiratory disease syndrome (ARDS) is a common complication of critical illness, associated with significant morbidity, prolonged intensive care unit (ICU) and hospital stay, and increased mortality. Inflammation plays a central role in ARDS, with inflammatory eicosanoid mediators produced from the ω-6 fatty acid arachidonic acid, such as leukotriene B4, being involved. The ω-3 fatty acids found in fish oil exert anti-inflammatory effects, including decreasing production of inflammatory eicosanoids from arachidonic acid. The ω-3 fatty acids are effective in models relevant to ARDS. Several randomized controlled trials of enteral formulas rich in ω-3 fatty acids, often in combination with other bioactive substances, have been conducted in patients with ARDS. Four of these trials reported marked clinical benefits, 2 reported no effect, and 1 reported a negative impact. A systematic review and meta-analysis of these 7 trials identified no overall effect on ventilator-free days or on ICU-free days. There was a small reduction in ICU length of stay and no overall effect on mortality. However, the authors formally identified that trials that used high fat in both treatment and control groups showed a significant reduction in mortality, while trials that used a high, or higher, fat treatment and a low-fat control group showed a trend toward an increase in mortality. It is concluded that differences in outcome reported among these studies largely relate to the relative fat contents of the treatment and control formulas. Further, it is concluded that high-fat enteral formulas should not be used in this patient group.

Is omega-3 fatty acids enriched nutrition support safe for critical ill patients? A systematic review and meta-analysis

OBJECTIVE

To systematically review the effects of omega-3 poly unsaturated fatty acids (FA) enriched nutrition support on the mortality of critically illness patients.

METHODS

Databases of Medline, ISI, Cochrane Library, and Chinese Biomedicine Database were searched and randomized controlled trials (RCTs) were identified. We enrolled RCTs that compared fish oil enriched nutrition support and standard nutrition support. Major outcome is mortality. Methodological quality assessment was conducted based on Modified Jadad's score scale. For control heterogeneity, we developed a method that integrated I2 test, nutritional support route subgroup analysis and clinical condition of severity. RevMan 5.0 software (The Nordic Cochrane Centre, Copenhagen, Denmark) was used for meta-analysis.

RESULTS

Twelve trials involving 1208 patients that met all the inclusion criteria. Heterogeneity existed between the trials. A random model was used, there was no significant effect on mortality RR, 0.82, 95% confidence interval (CI) (0.62, 1.09), p = 0.18. Knowing that the route of fish oil administration may affect heterogeneity, we categorized the trials into two sub-groups: parenteral administration (PN) of omega-3 and enteral administration (EN) of omega-3. Six trials administered omega-3 FA through PN. Pooled results indicated that omega-3 FA had no significant effect on mortality, RR 0.76, 95% CI (0.52, 1.10), p = 0.15. Six trials used omega-3 fatty acids enriched EN. After excluded one trial that was identified as source of heterogeneity, pooled data indicated omega-3 FA enriched EN significant reduce mortality, RR=0.69, 95% CI [0.53, 0.91] (p = 0.007).

CONCLUSION

Omega-3 FA enriched nutrition support is safe. Due to the limited sample size of the included trials, further large-scale RCTs are needed.

Enteral fish oil in critical illness: perspectives and systematic review

PURPOSE OF REVIEW

To summarize recent research addressing the role of enteral fish oil supplementation in critical illness.

RECENT FINDINGS

A number of new multicenter trials examining both the use of fish oil given as a supplement to enteral nutrition support and given as a separate bolus, independent of nutrition delivery, have recently been reported.

SUMMARY

Mechanistic data suggest that administration of fish oil may help attenuate the systemic inflammatory response and allow for appropriate resolution of inflammation in critically ill patients. Recent data indicate that enteral fish oil given as a continuous infusion as part of complete nutrition improves outcome in critically ill patients, especially those with acute lung injury/acute respiratory distress syndrome. In contrast, the bolus administration of fish oil cannot be recommended as clinically beneficial in acute lung injury/acute respiratory distress syndrome patients. Recent trials indicate that pharmacologically administered nutrients should be studied in the same manner as other new drugs, with appropriate attention to early dosing trials, proper pre-enrollment patient selection, and understanding of the role of concomitant protein/calorie nutrition. More research continues to be needed to optimize the proper patient, dose, and timing of administration for enteral fish oil therapy in the ICU.

Anti-Inflammatory and Anti-Oxidative Nutrition in Hypoalbuminemic Dialysis Patients (AIONID) study: results of the pilot-feasibility, double-blind, randomized, placebo-controlled trial

BACKGROUND

Low serum albumin is common and associated with protein-energy wasting, inflammation, and poor outcomes in maintenance hemodialysis (MHD) patients. We hypothesized that in-center (in dialysis clinic) provision of high-protein oral nutrition supplements (ONS) tailored for MHD patients combined with anti-oxidants and anti-inflammatory ingredients with or without an anti-inflammatory appetite stimulator (pentoxifylline, PTX) is well tolerated and can improve serum albumin concentration.

METHODS

Between January 2008 and June 2010, 84 adult hypoalbuminemic (albumin <4.0 g/dL) MHD outpatients were double-blindly randomized to receive 16 weeks of interventions including ONS, PTX, ONS with PTX, or placebos. Nutritional and inflammatory markers were compared between the four groups.

RESULTS

Out of 84 subjects (mean ± SD; age, 59 ± 12 years; vintage, 34 ± 34 months), 32 % were Blacks, 54 % females, and 68 % diabetics. ONS, PTX, ONS plus PTX, and placebo were associated with an average change in serum albumin of +0.21 (P = 0.004), +0.14 (P = 0.008), +0.18 (P = 0.001), and +0.03 g/dL (P = 0.59), respectively. No related serious adverse events were observed. In a predetermined intention-to-treat regression analysis modeling post-trial serum albumin as a function of pre-trial albumin and the three different interventions (ref = placebo), only ONS without PTX was associated with a significant albumin rise (+0.17 ± 0.07 g/dL, P = 0.018).

CONCLUSIONS

In this pilot-feasibility, 2 × 2 factorial, placebo-controlled trial, daily intake of a CKD-specific high-protein ONS with anti-inflammatory and anti-oxidative ingredients for up to 16 weeks was well tolerated and associated with slight but significant increase in serum albumin levels. Larger long-term controlled trials to examine hard outcomes are indicated.

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.

Stearidonic and γ-linolenic acids in echium oil improves glucose disposal in insulin resistant monkeys

Echium oil (EO) contains stearidonic acid (18:4), a n-3 polyunsaturated fatty acids (PUFAs), and gamma-linolenic acids (18:3), a n-6 PUFA that can be converted to long chain (LC)-PUFAs. We aimed to compare a safflower oil (SO)-enriched diet to EO- and fish oil (FO)-enriched diets on circulating and tissue PUFAs levels and glycemic, inflammatory, and cardiovascular health biomarkers in insulin resistant African green monkeys. In a Latin-square cross-over study, eight monkeys consumed matched diets for 6 weeks with 3-week washout periods. Monkeys consuming FO had significantly higher levels of n-3 LC-PUFAs and EO supplementation resulted in higher levels of circulating n-3 LC-PUFAs and a significant increase in dihomo-gamma linolenic acid (DGLA) in red blood cells and muscle. Glucose disposal was improved after EO consumption. These data suggest that PUFAs in EO supplementation have the capacity to alter circulating, RBC and muscle LC-PUFA levels and improve glucose tolerance in insulin-resistant monkeys.

Effect of enteral feeding with ginger extract in acute respiratory distress syndrome

PURPOSE

The purpose of this study is to evaluate the effects of an enteral diet enriched with ginger extract on inflammatory factors, respiratory profile, and outcome of patients with acute respiratory distress syndrome (ARDS).

MATERIALS AND METHODS

Thirty-two patients with ARDS were randomized to receive a high-protein enteral diet enriched with ginger or placebo. Serum levels of interleukin (IL) 1, IL-6, tumor necrosis factor α, and leukotriene B4; red blood cell glutathione; oxygenation; and static compliance were measured on days 0, 5, and 10.

RESULTS

Patients fed enteral diet enriched with ginger had significantly lower serum levels of IL-1, IL-6, and tumor necrosis factor α and higher level of RBC glutathione on days 5 and 10 compared with control group (P < .05). Significant improvement in oxygenation was observed on day 5 (P = .02) and 10 (P = .003) in ginger group compared with control group. Static compliance was increased on day 5 (P = .01) in ginger group compared with control group. A significant difference was found in duration of mechanical ventilation (P = .02) and length of intensive care unit stay (P = .04) in favor of ginger group. We did not find any difference in barotraumas, organ failure, and mortality between the study groups.

CONCLUSIONS

An enteral diet supplemented with ginger in patients with ARDS may be beneficial for gas exchange and could decrease duration of mechanical ventilation and length of stay in intensive care unit.

Aspirin-triggered resolvin D1 reduces mucosal inflammation and promotes resolution in a murine model of acute lung injury

Acute lung injury (ALI) is a severe illness with excess mortality and no specific therapy. Protective actions were recently uncovered for docosahexaenoic acid-derived mediators, including D-series resolvins. Here, we used a murine self-limited model of hydrochloric acid-induced ALI to determine the effects of aspirin-triggered resolvin D1 (AT-RvD1; 7S,8R,17R-trihydroxy-4Z,9E,11E,13Z,15E,19Z-docosahexaenoic acid) on mucosal injury. RvD1 and its receptor ALX/FPR2 were identified in murine lung after ALI. AT-RvD1 (~0.5-5 μg kg(-1)) decreased peak inflammation, including bronchoalveolar lavage fluid (BALF) neutrophils by ~75%. Animals treated with AT-RvD1 had improved epithelial and endothelial barrier integrity and decreased airway resistance concomitant with increased BALF epinephrine levels. AT-RvD1 inhibited neutrophil-platelet heterotypic interactions by downregulating both P-selectin and its ligand CD24. AT-RvD1 also significantly decreased levels of BALF pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, Kupffer cells, and tumor necrosis factor-α, and decreased nuclear factor-κB-phosphorylated p65 nuclear translocation. Taken together, these findings indicate that AT-RvD1 displays potent mucosal protection and promotes catabasis after ALI.

Nutritional immunomodulation in critically ill children with acute lung injury: feasibility and impact on circulating biomarkers

OBJECTIVE

Respiratory failure caused by acute lung injury or acute respiratory distress syndrome is associated with significant morbidity in children. Enteral nutrition enriched with eicosapentaenoic acid, γ-linolenic acid and antioxidants (eicosapentaenoic acid + γ-linolenic acid) can safely modulate plasma phospholipid fatty acid profiles, reduce inflammation, and improve clinical outcomes in adults. There is little information regarding the use of enteral eicosapentaenoic acid + γ-linolenic acid to modulate plasma phospholipid fatty acid profiles in children. We sought to determine if continuous feeding of enteral nutrition containing eicosapentaenoic acid, γ-linolenic acid, and antioxidants was feasible in critically ill children with acute lung injury or acute respiratory distress syndrome. We further evaluated the impact of such an approach on the alteration of plasma phospholipid fatty acid concentrations.

DESIGN

Prospective, blinded, randomized, controlled, multicenter trial.

SETTING

PICU.

PATIENTS

Twenty-six critically ill children (age 6.2 ± 0.9 yr, PaO2/FIO2 185 ± 15) with the diagnosis of acute lung injury or acute respiratory distress syndrome.

INTERVENTIONS

Mechanically ventilated children received either eicosapentaenoic acid + γ-linolenic acid or a standard pediatric enteral formula. Clinical, biochemical, plasma fatty acid, and safety data were assessed at baseline, study days 4 and 7.

MEASUREMENTS AND MAIN RESULTS

At baseline, there were no significant differences in the two study groups. Both groups met enteral feeding goals within 30 hrs and had similar caloric delivery. There were no differences in formula tolerance as measured by serum chemistries, liver and renal function, and hematology studies after 7 days of feeding either eicosapentaenoic acid + γ-linolenic acid or pediatric enteral formula. On study day 4 and 7, plasma phospholipid fatty acid profiles in the eicosapentaenoic acid + γ-linolenic acid group showed a significant increase in anti-inflammatory circulating markers.

CONCLUSIONS

Providing enteral nutrition with eicosapentaenoic acid + γ-linolenic acid to critically ill children with lung injury was feasible and caloric goals were met within 30 hrs. This feeding protocol effectively modulated plasma phospholipid fatty acid concentrations to reflect an anti-inflammatory profile. This study provides data to inform future outcome studies using enteral eicosapentaenoic acid + γ-linolenic acid in children with lung injury.

Resolvin E1 promotes phagocytosis-induced neutrophil apoptosis and accelerates resolution of pulmonary inflammation

Inappropriate neutrophil activation contributes to the pathogenesis of acute lung injury (ALI). Apoptosis is essential for removal of neutrophils from inflamed tissues and timely resolution of inflammation. Resolvin E1 (RvE1) is an endogenous lipid mediator derived from the ω-3 polyunsaturated fatty acid eicosapentaenoic acid that displays proresolving actions. Because the balance of prosurvival and proapoptosis signals determines the fate of neutrophils, we investigated the impact of RvE1 on neutrophil apoptosis and the outcome of neutrophil-mediated pulmonary inflammation in mice. Culture of human neutrophils with RvE1 accelerated apoptosis evoked by phagocytosis of opsonized Escherichia coli or yeast. RvE1 through the leukotriene B(4) receptor BLT1 enhanced NADPH oxidase-derived reactive oxygen species generation and subsequent activation of caspase-8 and caspase-3. RvE1 also attenuated ERK and Akt-mediated apoptosis-suppressing signals from myeloperoxidase, serum amyloid A, and bacterial DNA, shifting the balance of pro- and anti-survival signals toward apoptosis via induction of mitochondrial dysfunction. In mice, RvE1 treatment enhanced the resolution of established neutrophil-mediated pulmonary injury evoked by intratracheal instillation or i.p. administration of live E. coli or intratracheal instillation of carrageenan plus myeloperoxidase via facilitating neutrophil apoptosis and their removal by macrophages. The actions of RvE1 were prevented by the pan-caspase inhibitor zVAD-fmk. These results identify a mechanism, promotion of phagocytosis-induced neutrophil apoptosis and mitigation of potent anti-apoptosis signals, by which RvE1 could enhance resolution of acute lung inflammation.

Emerging drugs for the treatment of sepsis

INTRODUCTION

Despite improvement in medical care, severe sepsis and septic shock remain an unmet medical need. Their incidence is steadily increasing and the worldwide mortality ranges between 30% and 50%. This generates the need for agents that modulate the immune function of the host.

AREAS COVERED

Available agents can be divided into three categories according to their mechanism of action: i) agents that block bacterial products and inflammatory mediators. Hemoperfusion with polymyxin B embedded fiber device that blocks bacterial lipopolysaccharides (LPS) has given promising clinical results. Blockade of TNF-α with afelimomab and CytoFab appears promising; ii) modulators of immune function. Hydrocortisone stress replacement, intravenous infusion of clarithromycin and immunonutrition with omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) have all yielded positive clinical results. Recombinant thrombomodulin for patients with disseminated intravascular coagulation appears a promising alternative; and iii) immunostimulation. Meta-analysis of conducted trials disclosed the decrease of mortality in septic shock after administration of immunoglobulin preparations enriched with IgM.

EXPERT OPINION

The underlying pathophysiologic mechanisms in septic patients are highly individualized. As such, specific tools should be developed in the near future to define these differences and tailor therapeutic strategies accordingly.

Comparison of growth, serum biochemistries and n-6 fatty acid metabolism in rats fed diets supplemented with high-gamma-linolenic acid safflower oil or borage oil for 90 days

Recently, steps have been taken to further developments toward increasing gamma-linolenic acid (GLA) concentration and lowering costs in plant seed oils using transgenic technology. Through identification and expression of a fungal delta-6 desaturase gene in the high linoleic acid safflower plant, the seeds from this genetic transformation produce oil with >40% GLA (high GLA safflower oil (HGSO)). The aim of the study was to compare the effects of feeding HGSO to a generally recognized as safe source of GLA, borage oil, in a 90 day safety study in rats. Weanling male and female Sprague-Dawley rats were fed a semi-synthetic, fat free, pelleted diet (AIN93G) supplemented with a 10% (wt/wt) oil blend containing HGSO or borage oil, with equivalent GLA levels. Results demonstrated that feeding diets containing HGSO or borage oil for 90 days had similar biologic effects with regard to growth characteristics, body composition, behavior, organ weight and histology, and parameters of hematology and serum biochemistries in both sexes. Metabolism of the primary n-6 fatty acids in plasma and organ phospholipids was similar, despite minor changes in females. We conclude that HGSO is biologically equivalent to borage oil and provides a safe alternative source of GLA in the diet.