The role of fatty acid metabolism in acute lung injury: a special focus on immunometabolism

Reputable evidence from multiple studies suggests that excessive and uncontrolled inflammation plays an indispensable role in mediating, amplifying, and protracting acute lung injury (ALI). Traditionally, immunity and energy metabolism are regarded as separate functions regulated by distinct mechanisms, but recently, more and more evidence show that immunity and energy metabolism exhibit a strong interaction which has given rise to an emerging field of immunometabolism. Mammalian lungs are organs with active fatty acid metabolism, however, during ALI, inflammation and oxidative stress lead to a series metabolic reprogramming such as impaired fatty acid oxidation, increased expression of proteins involved in fatty acid uptake and transport, enhanced synthesis of fatty acids, and accumulation of lipid droplets. In addition, obesity represents a significant risk factor for ALI/ARDS. Thus, we have further elucidated the mechanisms of obesity exacerbating ALI from the perspective of fatty acid metabolism. To sum up, this paper presents a systematical review of the relationship between extensive fatty acid metabolic pathways and acute lung injury and summarizes recent advances in understanding the involvement of fatty acid metabolism-related pathways in ALI. We hold an optimistic believe that targeting fatty acid metabolism pathway is a promising lung protection strategy, but the specific regulatory mechanisms are way too complex, necessitating further extensive and in-depth investigations in future studies.

Does dietary linseed or canola oil affect lipid metabolism, immunity, and n-3 polyunsaturated fatty acids content in quail eggs?

One of the most intriguing areas of research and innovation in the animal production and food sector recently has been designed-enriched products. These items are regarded as functional foods because they feature components that have advantageous physiological impacts on human health. In the production of poultry, designed eggs constitute a significant category of functional foods. The present study hypothesized that adding different kinds of oils to quail diets will help produce designer eggs rich in omega-3 and 6 fatty acids in addition to enhancing productive performance. So, this study examined how linseed (flaxseed) and canola oils with various levels can affect lipid metabolism, immune function, and the amount of n-3 polyunsaturated fatty acids (n-3 PUFA) in Japanese quail eggs. This work was conducted using 3 different vegetable oils (sunflower, linseed, and canola oils) and 3 different antioxidant supplements (0, 250 mg vitamin E/kg feed, and 1,000 mg ginger/kg feed) in a 3 × 3 factorial experiment. When linseed or canola oil was added to the diet, the number of fatty acids in the egg yolks of Japanese quail layers fell by (12.7 and 18.9%) and (41.4 and 24.6%), respectively. The amounts of saturated and monounsaturated fatty acids in total eggs fell by 21.9 and 14.6% and 24.5 and 15.8%, respectively, at 20 wk of age. However, when linseed and canola oil were added to the diet, the sum n-3 PUFA content in the egg yolk of Japanese quail-laying hens was noticeably raised at 15 and 20 wk of age. At 15 and 20 wk of age, the same groups' total n-6 PUFA content considerably increased compared to the group that did not receive flaxseed. In conclusion, during the laying period of Japanese quail, linseed oil, canola oil, vitamin E, or ginger positively affected productivity, blood hematology, constituents, resistance, lipid digestion system, and antioxidative properties in serum and egg yolk.

Role of nutrition in patients with coexisting chronic obstructive pulmonary disease and sarcopenia

Chronic obstructive pulmonary disease (COPD) is one of the most common chronic diseases in the elderly population and is characterized by persistent respiratory symptoms and airflow obstruction. During COPD progression, a variety of pulmonary and extrapulmonary complications develop, with sarcopenia being one of the most common extrapulmonary complications. Factors that contribute to the pathogenesis of coexisting COPD and sarcopenia include systemic inflammation, hypoxia, hypercapnia, oxidative stress, protein metabolic imbalance, and myocyte mitochondrial dysfunction. These factors, individually or in concert, affect muscle function, resulting in decreased muscle mass and strength. The occurrence of sarcopenia severely affects the quality of life of patients with COPD, resulting in increased readmission rates, longer hospital admission, and higher mortality. In recent years, studies have found that oral supplementation with protein, micronutrients, fat, or a combination of nutritional supplements can improve the muscle strength and physical performance of these patients; some studies have also elucidated the possible underlying mechanisms. This review aimed to elucidate the role of nutrition among patients with coexisting COPD and sarcopenia.

Metabolomic analysis of maternal mid-gestation plasma and cord blood in autism spectrum disorders

The discovery of prenatal and neonatal molecular biomarkers has the potential to yield insights into autism spectrum disorder (ASD) and facilitate early diagnosis. We characterized metabolomic profiles in ASD using plasma samples collected in the Norwegian Autism Birth Cohort from mothers at weeks 17-21 gestation (maternal mid-gestation, MMG, n = 408) and from children on the day of birth (cord blood, CB, n = 418). We analyzed associations using sex-stratified adjusted logistic regression models with Bayesian analyses. Chemical enrichment analyses (ChemRICH) were performed to determine altered chemical clusters. We also employed machine learning algorithms to assess the utility of metabolomics as ASD biomarkers. We identified ASD associations with a variety of chemical compounds including arachidonic acid, glutamate, and glutamine, and metabolite clusters including hydroxy eicospentaenoic acids, phosphatidylcholines, and ceramides in MMG and CB plasma that are consistent with inflammation, disruption of membrane integrity, and impaired neurotransmission and neurotoxicity. Girls with ASD have disruption of ether/non-ether phospholipid balance in the MMG plasma that is similar to that found in other neurodevelopmental disorders. ASD boys in the CB analyses had the highest number of dysregulated chemical clusters. Machine learning classifiers distinguished ASD cases from controls with area under the receiver operating characteristic (AUROC) values ranging from 0.710 to 0.853. Predictive performance was better in CB analyses than in MMG. These findings may provide new insights into the sex-specific differences in ASD and have implications for discovery of biomarkers that may enable early detection and intervention.

Omega-3 Polyunsaturated Fatty Acids (n-3 PUFAs) for Immunomodulation in COVID-19 Related Acute Respiratory Distress Syndrome (ARDS)

Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), might be complicated by Acute Respiratory Distress Syndrome (ARDS) caused by severe lung damage. It is relevant to find treatments for COVID-19-related ARDS. Currently, DHA and EPA n-3 PUFAs, known for their immunomodulatory activities, have been proposed for COVID-19 management, and clinical trials are ongoing. Here, examining COVID-19-related ARDS immunopathology, we reference in vitro and in vivo studies, indicating n-3 PUFA immunomodulation on lung microenvironment (bronchial and alveolar epithelial cells, macrophages, infiltrating immune cells) and ARDS, potentially affecting immune responses in COVID-19-related ARDS. Concerning in vitro studies, evidence exists of the potential anti-inflammatory activity of DHA on airway epithelial cells and monocytes/macrophages; however, it is necessary to analyze n-3 PUFA immunomodulation using viral experimental models relevant to SARS-CoV-2 infection. Then, although pre-clinical investigations in experimental acute lung injury/ARDS revealed beneficial immunomodulation by n-3 PUFAs when extracellular pathogen infections were used as lung inflammatory models, contradictory results were reported using intracellular viral infections. Finally, clinical trials investigating n-3 PUFA immunomodulation in ARDS are limited, with small samples and contradictory results. In conclusion, further in vitro and in vivo investigations are needed to establish whether n-3 PUFAs may have some therapeutic potential in COVID-19-related ARDS.

Low n-6/n-3 Gestation and Lactation Diets Influence Early Performance, Muscle and Adipose Polyunsaturated Fatty Acid Content and Deposition, and Relative Abundance of Proteins in Suckling Piglets

Elevated omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) ratios in swine diets can potentially impose a higher risk of inflammatory and metabolic diseases in swine. A low ratio between the two omega PUFAs has beneficial effects on sows' and piglets' production performance and immunity status. At present, there are few studies on how sow nutrition directly affects the protein and fat deposition in suckling piglets. Two groups of sows were fed diets with high or low n-6/n-3 polyunsaturated ratios of 13:1 (SOY) and 4:1 (LIN), respectively, during gestation and lactation. Longissimus dorsi muscle and adipose tissue from newborn piglets, nourished only with sow's milk, were subjected to fatty acid profiling by gas chromatography-mass spectrometry (GC-MS) and to proteomics assays based on nano-liquid chromatography coupled to high-resolution tandem mass spectrometry (nLC-HRMS). Fatty acid profiles on both muscle and adipose tissues resembled the magnitude of the differences between fatty acid across diets. Proteomic analysis revealed overabundance of 4 muscle and 11 adipose tissue proteins in SOY compared to LIN in both piglet tissues. The detected overabundance of haptoglobin, an acute-phase protein, and the stimulation of protein-coding genes and proteins related to the innate immune response and acute inflammatory response could be associated with the pro-inflammatory role of n-6 PUFAs.

Diversity of Volatile Compounds in Raw Milk with Different n-6 to n-3 Fatty Acid Ratio

Simple Summary

In production, milk that is more beneficial to human health is obtained by adjusting the ratio of n-6 and n-3 fatty acids; however, the effect the regulation will have on the volatile substances in milk is unknown. In this study, gas chromatography–ion mobility spectrometry combined with principal component analysis was used to establish the fingerprint of volatile substances in raw milk to identify the types of volatile substances. The results show that a total of 34 target compounds were identified, and there were differences in the types and contents of volatile compounds among different treatment groups. The main reason for these differences is that lipid is degraded and aldehydes and ketones are produced in the adjusted-proportion group.

Abstract

Fatty acid profiles may affect the flavor of milk. The diversity of volatile compounds in raw milk with different ratios of n-6 to n-3 fatty acids (8:1, 4:1, and 3:1) was studied. Gas chromatography–ion mobility spectroscopy (GC–IMS) is a promising technology for the accurate characterization and detection of volatile organic compounds in agricultural products, but its application in milk is rare or even unavailable. In this experiment, GC–IMS fingerprints along with principal component analysis (PCA) were used to study the flavor fingerprints of fresh milk samples with different percentages. Thirty-four typical target compounds were identified in total. A diversity of flavor compounds in raw milk with different n-6/n-3 was observed. After reduction of the proportion, the concentrations of volatile compounds, such as hexanoic acid (dimer and monomer), ethyl acetate, and 2-methylpropanoic acid (dimer and monomer) decreased, while those of 4-methyl-2-pentanone, pentanal, and acetone increased. We carried out PCA according to the signal strength of the identified volatile compounds, and the examination showed that it could precisely make a distinction among the samples in a comparative space. In conclusion, the results show that the volatile compounds are different as the proportion is different. The volatile compounds in raw milk are mainly hexanoic acid, ethyl acetate, and 2-methylpropanoic acid. After adjustment of the ratio, the flavor substances of the medium-ratio (MR) group were mainly ketones, while those of the low-ratio (LR) group were aldehydes. Therefore, in production, reducing the impact on volatile substances while adjusting the proportion of n-6 and n-3 fatty acids to obtain functional dairy products should be taken into consideration.

Dietary Inflammatory Index and Cross-Sectional Associations with Inflammation, Muscle Mass and Function in Healthy Old Adults

IMPORTANCE

Inflammaging is considered a driver of age-related loss of muscle mass and function (sarcopenia). As nutrition might play a role in this process, the Dietary Inflammatory Index® (DII) has been developed to quantify the inflammatory potential of an individual diet.

OBJECTIVES

We aimed to examine associations between the DII, inflammation, oxidative stress and sarcopenia-related parameters in healthy old compared to young adults.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included data of 79 community-dwelling, healthy old adults (65-85 years) and 59 young adults (18-35 years) who participated in a randomized controlled trial from April to December 2019.

MEASUREMENTS

The DII was computed with dietary data collected from 24-h recall interviews. Associations between the DII, inflammatory and oxidative stress markers as well as bioimpedance-derived body composition, handgrip strength and gait speed were determined with multiple linear regression analyses adjusted for age, sex, physical activity and insulin resistance.

RESULTS

Regression analyses revealed significant relationships between a higher interleukin (IL) 6 and IL-6:IL-10-ratio and higher percentage fat mass (%FM), waist-to-height-ratio (WHtR) as well as lower percentage skeletal muscle mass (%SMM) and gait speed exclusively in old adults. Subsequent analyses showed that IL-6 was associated with a pro-inflammatory diet as indicated by a higher DII, again exclusively in old adults (beta coefficient (β)= 0.027, standard error (SE) 0.013, p=0.037). While the DII was not related with handgrip strength or oxidative stress in neither old nor young adults, linear models confirmed that a higher DII was inversely associated with gait speed in old participants (β= -0.022, SE 0.006, p<0.001). Finally, a pro-inflammatory diet was significantly associated with higher %FM, WHtR and lower %SMM in both age groups.

CONCLUSION AND RELEVANCE

A pro-inflammatory diet reflected by the DII is associated with higher systemic inflammation, slower gait speed as well as lower muscle mass in old adults. Intervention studies are needed to examine whether anti-inflammatory dietary approaches can help to improve muscle mass and function and thus minimize the risk for sarcopenia in the long-term.

Necrotizing enterocolitis in the preterm: newborns medical and nutritional Management in a Single-Center Study

Necrotizing enterocolitis (NEC) is a typical disorder of preterm newborns, with a high mortality and morbidity rate. The therapeutic and nutritional management of disease depends on several factors. Its prognosis is linked, in addition to the severity of the disease and the need for surgery, to a correct enteral feeding in these patients. This study aims to identify the clinical characteristics of 18 patients with NEC, evaluating the different therapeutic paths undertaken, the type of formula used and the survival rate of this population. Average time of enteral nutrition before the NEC onset was 11,3 ± 11,6 days, with an average fasting period since the onset of 24 ± 18.9 days. 77.8% of patients received surgery and resumed enteral nutrition 17.7 ± 17.9 days after the intervention. The overall survival rate of our cohort was 55.5%. More prospective studies are needed to evaluate the long-term outcomes of survived children with NEC.

Abnormal n-6 fatty acid metabolism in cystic fibrosis contributes to pulmonary symptoms

Cystic fibrosis (CF) is a recessively inherited fatal disease that is the subject of extensive research and ongoing development of therapeutics targeting the defective protein, cystic fibrosis transmembrane conductance regulator (CFTR). Despite progress, the link between CFTR and clinical symptoms is incomplete. The severe CF phenotypes are associated with a deficiency of linoleic acid, which is the precursor of arachidonic acid. The release of arachidonic acid from membranes via phospholipase A₂ is the rate-limiting step for eicosanoid synthesis and is increased in CF, which contributes to the observed inflammation. A potential deficiency of docosahexaenoic acid may lead to decreased levels of specialized pro-resolving mediators. This pathophysiology may contribute to an early and sterile inflammation, mucus production, and to bacterial colonization, which further increases inflammation and potentiates the clinical symptoms. Advances in lipid technology will assist in elucidating the role of lipid metabolism in CF, and stimulate therapeutic modulations of inflammation.

Role of nutrition in immune response: Case of Covid-19

The relationships between nutrition and immunity have been the subject of several studies. The main fact lies in the deep entanglement between immunity, and nutritional state: all deficiencies in proteins, essential fatty acids, metallo-enzymes, vitamin factors, and antioxidant elements lead to a dysfunction of the immune system. On the other hand, some excess food (total lipid intake, type of fatty acids, simple sugars, etc.) can, also, have deleterious effects. The emergence of new infectious diseases with new pathogenic properties is a serious global health problem. Covid-19 infection (Coronavirus Disease-2019) caused by the coronavirus SARS-CoV2 (Severe Acute Respiratory Syndrome Coronavirus-2), is recognized as pandemic by the World Health Organization (WHO).This implies strict prevention measures, and a strategy to be developed throughout good hygiene, healthy and balanced diet, and compliance with the con-finement rules.

Current status of lipid emulsions in the prevention of intestinal failure-associated liver disease

PURPOSE OF REVIEW

The current review provides a summary of available lipid products and discusses current literature and the limitations to the use of various lipid products for treatment and prevention of intestinal failure-associated liver disease (IFALD) in pediatric patients dependent on parenteral nutrition.

RECENT FINDINGS

Improvements in markers of cholestasis and liver function have been seen with minimizing soybean lipid, fish oil lipid, and mixed fish oil-containing lipid emulsions. Soybean-based lipid products are thought to be the biggest contributor to development of IFALD. Mixed fish oil-containing lipid emulsions are most promising for minimizing and improving IFALD.

SUMMARY

Several types of lipid-based products are available for parenteral nutrition. Newer products like the mixed fish oil-containing-based lipid emulsions, that closely mimic the lipid composition provided by enteral feeding, may impact prevention and treatment of IFALD. Limitations exist in the current literature regarding mixed fish oil-containing-based emulsions, as many of the studies were designed to show efficacy with regard to growth, not prevention or treatment of IFALD. Based on available literature, it is reasonable to make some recommendations with regard to product selection for lipid provision.

Nutrition in Necrotizing Enterocolitis and Following Intestinal Resection

This review aims to discuss the role of nutrition and feeding practices in necrotizing enterocolitis (NEC), NEC prevention, and its complications, including surgical treatment. A thorough PubMed search was performed with a focus on meta-analyses and randomized controlled trials when available. There are several variables in nutrition and the feeding of preterm infants with the intention of preventing necrotizing enterocolitis (NEC). Starting feeds later rather than earlier, advancing feeds slowly and continuous feeds have not been shown to prevent NEC and breast milk remains the only effective prevention strategy. The lack of medical treatment options for NEC often leads to disease progression requiring surgical resection. Following resection, intestinal adaptation occurs, during which villi lengthen and crypts deepen to increase the functional capacity of remaining bowel. The effect of macronutrients on intestinal adaptation has been extensively studied in animal models. Clinically, the length and portion of intestine that is resected may lead to patients requiring parenteral nutrition, which is also reviewed here. There remain significant gaps in knowledge surrounding many of the nutritional aspects of NEC and more research is needed to determine optimal feeding approaches to prevent NEC, particularly in infants younger than 28 weeks and <1000 grams. Additional research is also needed to identify biomarkers reflecting intestinal recovery following NEC diagnosis individualize when feedings should be safely resumed for each patient.

Early and reversible changes to the hippocampal proteome in mice on a high-fat diet

Background

The rise in global obesity makes it crucial to understand how diet drives obesity-related health conditions, such as premature cognitive decline and Alzheimer's disease (AD). In AD hippocampal-dependent episodic memory is one of the first types of memory to be impaired. Previous studies have shown that in mice fed a high-fat diet (HFD) episodic memory is rapidly but reversibly impaired.

Methods

In this study we use hippocampal proteomics to investigate the effects of HFD in the hippocampus. Mice were fed either a low-fat diet (LFD) or HFD containing either 10% or 60% (Kcal) from fat for 3 days, 1 week or 2 weeks. One group of mice were fed the HFD for 1 week and then returned to the LFD for a further week. Primary hippocampal cultures were challenged with palmitic acid (PA), the most common long-chain saturated FA in the Western diet, and with the anti-inflammatory, n-3 polyunsaturated FA, docosahexaenoic acid (DHA), or a combination of the two to ascertain effects of these fatty acids on dendritic structure.

Results

HFD-induced changes occur in hippocampal proteins involved in metabolism, inflammation, cell stress, cell signalling, and the cytoskeleton after 3 days, 1 week and 2 weeks of HFD. Replacement of the HFD after 1 week by a low-fat diet (LFD) for a further week resulted in partial recovery of the hippocampal proteome. Microtubule-associated protein 2 (MAP2), one of the earliest proteins changed, was used to investigate the impact of fatty acids (FAs) on hippocampal neuronal morphology. PA challenge resulted in shorter and less arborised dendrites while DHA had no effect when applied alone but counteracted the effects of PA when FAs were used in combination. Dendritic morphology recovered when PA was removed from the cell culture media.

Conclusion

This study provides evidence for the rapid and reversible effects of diet on the hippocampal proteome and the impact of PA and DHA on dendritic structure.

Role of Diet in Chronic Obstructive Pulmonary Disease Prevention and Treatment

Chronic obstructive pulmonary disease is one of the leading causes of morbidity and mortality worldwide and a growing healthcare problem. Identification of modifiable risk factors for prevention and treatment of COPD is urgent, and the scientific community has begun to pay close attention to diet as an integral part of COPD management, from prevention to treatment. This review summarizes the evidence from observational and clinical studies regarding the impact of nutrients and dietary patterns on lung function and COPD development, progression, and outcomes, with highlights on potential mechanisms of action. Several dietary options can be considered in terms of COPD prevention and/or progression. Although definitive data are lacking, the available scientific evidence indicates that some foods and nutrients, especially those nutraceuticals endowed with antioxidant and anti-inflammatory properties and when consumed in combinations in the form of balanced dietary patterns, are associated with better pulmonary function, less lung function decline, and reduced risk of COPD. Knowledge of dietary influences on COPD may provide health professionals with an evidence-based lifestyle approach to better counsel patients toward improved pulmonary health.

Modulating Effect of Diet on Alzheimer's Disease

As life expectancy is growing, neurodegenerative disorders, such as Alzheimer's disease, are increasing. This disease is characterised by the accumulation of intracellular neurofibrillary tangles formed by hyperphosphorylated tau protein, senile plaques composed of an extracellular deposit of β-amyloid peptide (Aβ), and neuronal loss. This is accompanied by deficient mitochondrial function, increased oxidative stress, altered inflammatory response, and autophagy process impairment. The present study gathers scientific evidence that demonstrates that specific nutrients exert a direct effect on both Aβ production and Tau processing and their elimination by autophagy activation. Likewise, certain nutrients can modulate the inflammatory response and the oxidative stress related to the disease. However, the extent to which these effects come with beneficial clinical outcomes remains unclear. Even so, several studies have shown the benefits of the Mediterranean diet on Alzheimer's disease, due to its richness in many of these compounds, to which can be attributed their neuroprotective properties due to the pleiotropic effect they show on the aforementioned processes. These indications highlight the potential role of adequate dietary recommendations for clinical management of both Alzheimer's diagnosed patients and those in risk of developing it, emphasising once again the importance of diet on health.

Anti-inflammatory effects of docosahexaenoic acid: Implications for its cancer chemopreventive potential

The implication of inflammatory tissue damage in pathophysiology of human cancer as well as some metabolic disorders has been under intense investigation. Numerous studies have identified a series of critical signaling molecules involved in cellular responses to inflammatory stimuli. These include nuclear factor κB, peroxisome proliferator-activated receptor γ, nuclear factor erythroid 2 p45-related factor 2 and sterol regulatory element-binding protein 1. The proper regulation of these transcription factors mediating pro- and anti-inflammatory signaling hence provides an important strategy for the chemoprevention of inflammation-associated cancer. There is compelling evidence supporting that dietary supplementation with fish oil-derived ω-3 polyunsaturated fatty acids including docosahexaenoic acid (DHA) ameliorates symptomatic inflammation associated with cancer as well as other divergent human disorders. Acute or physiologic inflammation is an essential body's first line of defence to microbial infection and tissue injuries, but it must be properly completed by a process termed 'resolution'. Failure of resolution mechanisms can result in persistence of inflammation, leading to chronic inflammatory conditions and related malignancies. The phagocytic engulfment of apoptotic neutrophils and clearance of their potentially histotoxic contents by macrophages, called efferocytosis is an essential component in resolving inflammation. Of note, DHA is a precursor of endogenous proresolving lipid mediators which regulate the leukocyte trafficking and recruitment and thereby facilitate efferocytosis. Therefore, DHA and its metabolites may have a preventive potential in the management of human cancer which arises as a consequence of impaired resolution of inflammation as well as chronic inflammation.

The N3RO trial: a randomised controlled trial of docosahexaenoic acid to reduce bronchopulmonary dysplasia in preterm infants < 29 weeks' gestation

Background

Bronchopulmonary dysplasia (BPD) is a major cause of mortality and long-term respiratory and neurological morbidity in very preterm infants. While survival rates of very preterm infants have increased over the past two decades there has been no decrease in the rate of BPD in surviving infants. Evidence from animal and human studies has suggested potential benefits of docosahexaenoic acid (DHA), an n-3 long chain polyunsaturated fatty acid, in the prevention of chronic lung disease. This randomised controlled trial aims to determine the effectiveness of supplementary DHA in reducing the rate of BPD in infants less than 29 weeks’ gestation.

Methods/design

This is a multicentre, parallel group, randomised, blinded and controlled trial. Infants born less than 29 weeks’ gestation, within 3 days of first enteral feed and with parent informed consent are eligible to participate. Infants will be randomised to receive an enteral emulsion containing DHA or a control emulsion without DHA. The DHA emulsion will provide 60 mg/kg/day of DHA. The study emulsions will continue to 36 weeks’ postmenstrual age (PMA). The primary outcome is BPD as assessed by the requirement for supplemental oxygen and/or assisted ventilation at 36 weeks’ PMA. Secondary outcomes include the composite of death or BPD; duration of respiratory support and hospitalisation, major neonatal morbidities. The target sample size is 1244 infants (622 per group), which will provide 90 % power to detect a clinically meaningful absolute reduction of 10 % in the incidence of BPD between the DHA and control emulsion (two tailed α =0.05).

Discussion

DHA supplementation has the potential to reduce respiratory morbidity in very preterm infants. This multicentre trial will provide evidence on whether an enteral DHA supplement reduces BPD in very preterm infants.

Trial registration

Australia and New Zealand Clinical Trial Registry: ACTRN12612000503820. Registered 09 May 2012.

Metabolic Changes Precede the Development of Pulmonary Hypertension in the Monocrotaline Exposed Rat Lung

There is increasing interest in the potential for metabolic profiling to evaluate the progression of pulmonary hypertension (PH). However, a detailed analysis of the metabolic changes in lungs at the early stage of PH, characterized by increased pulmonary artery pressure but prior to the development of right ventricle hypertrophy and failure, is lacking in a preclinical animal model of PH. Thus, we undertook a study using rats 14 days after exposure to monocrotaline (MCT), to determine whether we could identify early stage metabolic changes prior to the manifestation of developed PH. We observed changes in multiple pathways associated with the development of PH, including activated glycolysis, increased markers of proliferation, disruptions in carnitine homeostasis, increased inflammatory and fibrosis biomarkers, and a reduction in glutathione biosynthesis. Further, our global metabolic profile data compare favorably with prior work carried out in humans with PH. We conclude that despite the MCT-model not recapitulating all the structural changes associated with humans with advanced PH, including endothelial cell proliferation and the formation of plexiform lesions, it is very similar at a metabolic level. Thus, we suggest that despite its limitations it can still serve as a useful preclinical model for the study of PH.

The Omega-3 Fatty Acid Docosahexaenoic Acid Modulates Inflammatory Mediator Release in Human Alveolar Cells Exposed to Bronchoalveolar Lavage Fluid of ARDS Patients

BACKGROUND

This study investigated whether the 1 : 2 ω-3/ω-6 ratio may reduce proinflammatory response in human alveolar cells (A549) exposed to an ex vivo inflammatory stimulus (bronchoalveolar lavage fluid (BALF) of acute respiratory distress syndrome (ARDS) patients). Methods. We exposed A549 cells to the BALF collected from 12 ARDS patients. After 18 hours, fatty acids (FA) were added as docosahexaenoic acid (DHA, ω-3) and arachidonic acid (AA, ω-6) in two ratios (1 : 2 or 1 : 7). 24 hours later, in culture supernatants were evaluated cytokines (TNF-α, IL-6, IL-8, and IL-10) and prostaglandins (PGE2 and PGE3) release. The FA percentage content in A549 membrane phospholipids, content of COX-2, level of PPARγ, and NF-κB binding activity were determined.

RESULTS

The 1 : 2 DHA/AA ratio reversed the baseline predominance of ω-6 over ω-3 in the cell membranes (P < 0.001). The proinflammatory cytokine release was reduced by the 1 : 2 ratio (P < 0.01 to <0.001) but was increased by the 1 : 7 ratio (P < 0.01). The 1 : 2 ratio reduced COX-2 and PGE2 (P < 0.001) as well as NF-κB translocation into the nucleus (P < 0.01), while it increased activation of PPARγ and IL-10 release (P < 0.001). Conclusion. This study demonstrated that shifting the FA supply from ω-6 to ω-3 decreased proinflammatory mediator release in human alveolar cells exposed to BALF of ARDS patients.

Omega-3 PUFA docosahexaenoic acid decreases LPS-stimulated MUC5AC production by altering EGFR-related signaling in NCI-H292 cells

Chronic obstructive pulmonary disease (COPD) is an inflammatory process characterized by airway mucus hypersecretion. Lipopolysaccharides (LPS) are known to stimulate the production of mucin 5AC (MUC5AC) via epidermal growth factor receptor (EGFR) in human airway cells. Noteworthy, we have previously demonstrated that EGFR/Rac1/reactive oxygen species (ROS)/matrix metalloproteinase 9 (MMP-9) is a key signaling cascade regulating MUC5AC production in airway cells challenged with LPS. Various reports have shown an inverse association between the intake of polyunsaturated fatty acids (PUFA) of the n-3 (omega-3) family or fish consumption and COPD. In the present study, we investigated the influence of docosahexaenoic acid (DHA), one of the most important omega-3 PUFA contained in fish oil, on the production of MUC5AC in LPS-challenged human airway cells NCI--H292. Our results indicate that DHA is capable of counteracting MUC5AC overproduction in LPS-stimulated cells by abrogating both EGFR phosphorylation and its downstream signaling pathway. This signaling pathway not only includes Rac1, ROS and MMP-9, but also NF-κB, since we have found that ROS require NF-κB activity to induce MMP-9 secretion and activation.

Acanthoic acid ameliorates lipopolysaccharide-induced acute lung injury

Acanthoic acid, a pimaradiene diterpene isolated from Acanthopanax koreanum, has been reported to have anti-inflammatory activities. However, the effects of acanthoic acid on LPS-induced acute lung injury have not been reported. The purpose of this study was to investigate the protective effect of acanthoic acid on LPS-induced ALI and to clarify the possible anti-inflammatory mechanisms. In vivo, an LPS-induced ALI model in mice was used to assess the protective effects of acanthoic acid on ALI. Meanwhile, mouse alveolar macrophages MH-S were stimulated with LPS in the presence or absence of acanthoic acid. The expressions of TNF-α, IL-6 and IL-1β were measured by ELISA. LXRα and NF-κB expression were detected by Western blot analysis. The results showed that acanthoic acid downregulated LPS-induced TNF-α, IL-6 and IL-1β production in BALF. MPO activity and lung wet-to-dry ratio were also inhibited by acanthoic acid. In addition, acanthoic acid attenuated lung histopathologic changes. In vitro, acanthoic acid inhibited inflammatory cytokines TNF-α, IL-6 and IL-1β production and NF-κB activation in LPS-stimulated alveolar macrophages. Acanthoic acid was found to up-regulated the expression of LXRα. The inhibition of acanthoic acid on LPS-induced cytokines and NF-κB activation can be abolished by LXRα siRNA. In conclusion, our results suggested that the protective effect of acanthoic acid on LPS-induced ALI was due to its ability to activate LXRα, thereby inhibiting LPS-induced inflammatory response.

Polyunsaturated Fatty Acids and Cytokines: Their Relationship in Acute Lung Injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are inflammatory diseases whose clinical severity depends on the grade of inflammatory response. Inflammatory cytokines are key elements in the pathogenesis of ALI/ARDS, and the occurrence of an imbalance between pro- and anti-inflammatory cytokines leads to additional non-pulmonary organ dysfunction which contributes to excess mortality rates.

Treatment of these patients includes nutrition support with lipids, usually soybean oil-based lipid emulsions, which are rich in omega (n)-6 polyunsaturated fatty acids (PUFAs) and deficient in n-3 PUFAs; however, too much n-6 PUFAs are detrimental due to their pro-inflammatory effects. Conversely, a large amount of experimental studies and some randomized clinical trials showed the benefits of the n-3 PUFA administration in the context of ALI because of their anti-inflammatory properties. Based on these data, several scientific societies recommended in their guidelines, with an A or B grade of recommendation, the use of n-3 PUFAs in ALI/ARDS patients. However, at present, the issue of lipid therapy in ALI/ARDS is still controversial due, at least in part, to inconclusive or contradicting results in several recent clinical trials using n-3 PUFAs.

Repeated intratracheal instillation of PM10 induces lipid reshaping in lung parenchyma and in extra-pulmonary tissues

Adverse health effects of air pollution attributed mainly to airborne particulate matter have been well documented in the last couple of decades. Short term exposure, referring to a few hours exposure, to high ambient PM10 concentration is linked to increased hospitalization rates for cardiovascular events, typically 24 h after air pollution peaks. Particulate matter exposure is related to pulmonary and cardiovascular diseases, with increased oxidative stress and inflammatory status. Previously, we have demonstrated that repeated intratracheal instillation of PM10sum in BALB/c mice leads to respiratory tract inflammation, creating in lung a condition which could potentially evolve in a systemic toxic reaction. Additionally, plasma membrane and tissue lipids are easily affected by oxidative stress and directly correlated with inflammatory products. With this aim, in the present investigation using the same model, we analyzed the toxic potential of PM10sum exposure on lipid plasma membrane composition, lipid peroxidation and the mechanisms of cells protection in multiple organs such as lung, heart, liver and brain. Obtained results indicated that PM10 exposure led to lung lipid reshaping, in particular phospholipid and cholesterol content increases; concomitantly, the generation of oxidative stress caused lipid peroxidation. In liver we found significant changes in lipid content, mainly due to an increase of phosphatidylcholine, and in total fatty acid composition with a more pronounced level of docosahexaenoic acid; these changes were statistically correlated to lung molecular markers. Heart and brain were similarly affected; heart was significantly enriched in triglycerides in half of the PM10sum treated mice. These results demonstrated a direct involvement of PM10sum in affecting lipid metabolism and oxidative stress in peripheral tissues that might be related to the serious systemic air-pollution effects on human health.

Negative confounding by essential fatty acids in methylmercury neurotoxicity associations

BACKGROUND

Methylmercury, a worldwide contaminant of fish and seafood, can cause adverse effects on the developing nervous system. However, long-chain n-3 polyunsaturated fatty acids in seafood provide beneficial effects on brain development. Negative confounding will likely result in underestimation of both mercury toxicity and nutrient benefits unless mutual adjustment is included in the analysis.

METHODS

We examined these associations in 176 Faroese children, in whom prenatal methylmercury exposure was assessed from mercury concentrations in cord blood and maternal hair. The relative concentrations of fatty acids were determined in cord serum phospholipids. Neuropsychological performance in verbal, motor, attention, spatial, and memory functions was assessed at 7 years of age. Multiple regression and structural equation models (SEMs) were carried out to determine the confounder-adjusted associations with methylmercury exposure.

RESULTS

A short delay recall (in percent change) in the California Verbal Learning Test (CVLT) was associated with a doubling of cord blood methylmercury (-18.9, 95% confidence interval [CI]=-36.3, -1.51). The association became stronger after the inclusion of fatty acid concentrations in the analysis (-22.0, 95% confidence interval [CI]=-39.4, -4.62). In structural equation models, poorer memory function (corresponding to a lower score in the learning trials and short delay recall in CVLT) was associated with a doubling of prenatal exposure to methylmercury after the inclusion of fatty acid concentrations in the analysis (-1.94, 95% CI=-3.39, -0.49).

CONCLUSIONS

Associations between prenatal exposure to methylmercury and neurobehavioral deficits in memory function at school age were strengthened after fatty acid adjustment, thus suggesting that n-3 fatty acids need to be included in analysis of similar studies to avoid underestimation of the associations with methylmercury exposure.

Nutritional management of the breastfeeding dyad

Milk is successfully produced by mothers regardless of their nutritional status. Nevertheless, the concentrations of some nutrients, specifically vitamins A, D, B1, B2, B3, B6, and B12, fatty acids, and iodine, in human milk depend on or are influenced by maternal diet. A healthy and varied diet during lactation ensures adequate maternal nutrition and optimal concentration of some nutrients in human milk. Exclusive breastfeeding meets the nutritional needs of infants for 6 months of life with the exception of vitamins D and K, which should be given to breastfed infants as supplements.

Respiratory hospitalisation of infants supplemented with docosahexaenoic acid as preterm neonates

AIM

To determine the effect of neonatal docosahexaenoic acid (DHA) supplementation in preterm infants on later respiratory-related hospitalisations.

METHODS

We enrolled 657 infants in a multicentre, randomised, controlled trial designed to study the long-term efficacy of higher dose dietary DHA in infants born <33 weeks' gestation. Treatment was with high DHA (∼1%) compared with standard DHA (∼0.3%) in breast milk or formula, given from the first week of life to term equivalent. Parent-reported hospital admissions to 18 months corrected age were recorded. The proportion of children hospitalised for lower respiratory tract (LRT) conditions and the mean number of hospitalisations per infant were determined.

RESULTS

Twenty-three per cent (154/657) of infants were hospitalised for LRT conditions. Seventy-three per cent (173/238) of admissions were for bronchiolitis. There was no significant effect of higher DHA on the proportion of infants admitted for LRT conditions (high DHA 22% vs. standard DHA 25%, adjusted relative risk 0.92, 95% confidence interval (CI) 0.68-1.24, P = 0.57) or in the mean number of admissions per infant (high DHA 0.34, standard DHA 0.38, adjusted ratio of means 0.91, 95% CI 0.63-1.32, P = 0.62). The sexes responded differently to treatment (interaction P = 0.046), with reduced admissions in boys given high DHA, but this was not statistically significant (high DHA 19%, standard DHA 28%, adjusted relative risk 0.69, 95% CI 0.46-1.04, P = 0.08).

CONCLUSIONS

Hospitalisation for LRT problems in the first 18 months for preterm infants was not reduced by neonatal supplementation with 1% DHA.

Purified fish oil eliminating linoleic and alpha linolenic acid meets essential fatty acid requirements in rats

This study examined whether purified fish oil (PFO) supplemented to an essential fatty acid deficient (EFAD) diet meets EFA needs in rats. The EFAD diet contained 10% hydrogenated coconut oil (HCO). A similar diet contained 7% HCO and 3% PFO which also provided 2.84% arachidonic acid (AA), 52.50% eicosapentaenoic acid (EPA) and 35.73% docosahexaenoic acid (DHA) but no linoleic acid (LA) or alpha linolenic acid (ALA). A 10% soybean oil control diet provided ample LA and ALA. After 4 weeks of feeding, blood glucose, plasma triglyceride and phospholipid fatty acid profiles, C-reactive protein (CRP), TNF and IL-6 were determined after saline or LPS injection. EFAD developed with the HCO diet with triene:tetraene ratios in plasma phospholipids >.20, which remained <.02 with the control and HCO+PFO diets. Mead acid levels significantly increased by a factor of 10 with the HCO diet compared to the AIN and HCO+PFO diets and were significantly lowest with the HCO+PFO diet. 18:1 n9 levels were significantly higher in plasma phospholipids and triglycerides with the HCO diet. CRP levels were significantly highest with the control diet and significantly lowest with the HCO diet. LPS significantly increased 18:1 n9 and cytokines, and decreased AA and plasma glucose in all diets and significantly increased plasma triglycerides and decreased plasma glucose in controls. Providing AA, EPA and DHA in EFAD prevents EFAD over the short-term as reflected in Mead acid production, triene:tetraene ratio, and de novo lipogenesis and may reduce the inflammatory response to LPS.

Maternal dietary DHA supplementation to improve inflammatory outcomes in the preterm infant

Dietary DHA (22:6n-3) is a long-chain PUFA that has provocative effects on inflammatory signal events that could potentially affect preterm infant health. It is well known that the essential fatty acid of the (n-3) series; α-linolenic acid (18:3n:3) can be desaturated and elongated in the liver endoplasmic reticulum and peroxisome to produce the 22-carbon DHA. Nevertheless, concern exists as to the efficiency of this mechanism in providing the preterm infant with adequate DHA. Activity of the δ-6-desaturase and the δ-5-desaturase necessary for DHA synthesis is decreased by protein deprivation. The combined effects of suboptimal intake of both DHA and protein in the preterm infants could have substantial clinical consequences.

The mode of administration of total parenteral nutrition and nature of lipid content influence the generation of peroxides and aldehydes

BACKGROUND & AIMS

The absence of light protection of neonatal total parenteral nutrition (PN) contributes to the generation of 4-hydroxynonenal and peroxides. 4-Hydroxynonenal is suspected to be involved in PN-related liver complications.

AIMS

To find a practical modality to reduce 4-hydroxynonenal in PN and assess in vivo the impact of PN containing low 4-hydroxynonenal concentration.

METHODS

Six modalities of delivering PN were compared for the in vitro generation of peroxides and 4-hydroxynonenal: 1) MV-AA-L: light-protected (-L) solution containing multivitamin (MV) mixed with amino acids + dextrose (AA); 2) MV-AA+L: MV-AA without photo-protection (+L); 3) MV-LIP+L: MV mixed with lipid emulsion (LIP). LIP was a) Intralipid20%(®) or b) Omegaven(®). Hepatic markers of oxidative stress (glutathione, F(2α)-isoprostanes, GS-HNE) and inflammation (mRNA of TNF-α and IL-1) were measured in newborn guinea pigs infused during 4-days with MV-AA+L compounded with Intralipid20%(®) or Omegaven(®).

RESULTS

Hydroperoxides and 4-hydroxynonenal were the lowest in MV-AA-L and the highest in MV-LIP+L. MV-AA+L with Omegaven(®) was associated with the lowest levels of markers of oxidative stress and inflammation.

CONCLUSION

Compared to Intralipid20%(®), Omegaven(®) reduces oxidative stress associated with PN and prevents liver inflammation. These findings offer an alternative strategy to light protection of PN, which in the clinical setting is a cumbersome modality.

Analysis of the effects of iron and vitamin C co-supplementation on oxidative damage, antioxidant response and inflammation in THP-1 macrophages

OBJECTIVES

The aims of the study were to test the susceptibility of THP-1 macrophages to develop oxidative stress and to deploy antioxidant defense mechanisms that insure the balance between the pro- and antioxidant molecules.

DESIGN AND METHODS

Differentiated THP-1 were incubated in the presence or absence of iron-ascorbate (Fe/As) (100/1000μM) and the antioxidants Trolox, BHT, α-Tocopherol and NAC.

RESULTS

Fe/As promoted the production of lipid peroxidation as reflected by the formation of malondialdehyde and H(2)O(2) along with reduced PUFA levels and elevated glutathione disulfide/total glutathione ratio, a reliable index of cellular redox status. THP-1 macrophages developed an increase in cytoplasmic SOD activity due in part to high cytoplasmic SOD1. On the other hand, a decline was noted in mRNA and protein of extra-cellular SOD3, as well as the activity of GSH-peroxidase, GSH-transferase and ATOX-1 expression.

CONCLUSIONS

Macrophages activated under conditions of oxidative stress do not adequately deploy a powerful endogenous antioxidant response, a situation that can lead to an enhanced inflammatory response.