Effects of postnatal omega-3 fatty acid supplementation on offspring pro-resolving mediators of inflammation at 6 months and 5 years of age: A double blind, randomized controlled clinical trial

Essential Fatty Acid Supplementation and Early Inflammation in Preterm Infants: Secondary Analysis of a Randomized Clinical Trial

INTRODUCTION

Postnatal inflammation is associated with increased mortality and adverse outcomes in preterm infants. The essential fatty acids arachidonic acid (ARA) and docosahexaenoic acid (DHA) are precursors of lipid mediators with a key role in resolving inflammation. Our aim was to investigate the effect of ARA and DHA supplementation on systemic inflammation in very preterm infants and to identify clinical factors associated with early inflammation.

METHODS

Secondary analysis of data from a randomized clinical trial (ImNuT study). Infants with gestational age (GA) less than 29 weeks were randomized to receive a daily enteral supplement with ARA 100 mg/kg and DHA 50 mg/kg (ARA:DHA group) or MCT oil (control group) from the second day of life to 36 weeks postmenstrual age. ARA, DHA, and four proinflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α) were analyzed in repeated dried blood samples from birth to day 28 and the area under the curve (AUC) for each variable was calculated.

RESULTS

The intention to treat population included 120 infants with mean (SD) GA 26.4 (1.7). The ARA:DHA group had significantly lower IL-6 levels from day 3 to day 28 compared to the control group, mean difference AUC log10 (95% CI): 0.16 (0.03-0.30) pg/mL, p = 0.018. There was no correlation between ARA or DHA blood concentrations and cytokine levels. Having a low gestational age was independently associated with increased levels of all cytokines during the first 4 weeks of life.

CONCLUSIONS

Enhanced supplementation with ARA and DHA may modulate inflammation in very preterm infants.

Something Smells Fishy: How Lipid Mediators Impact the Maternal-Fetal Interface and Neonatal Development

Normal pregnancy relies on inflammation for implantation, placentation, and parturition, but uncontrolled inflammation can lead to poor maternal and infant outcomes. Maternal diet is one modifiable factor that can impact inflammation. Omega-3 and -6 fatty acids obtained through the diet are metabolized into bioactive compounds that effect inflammation. Recent evidence has shown that the downstream products of omega-3 and -6 fatty acids may influence physiology during pregnancy. In this review, the current knowledge relating to omega-3 and omega-6 metabolites during pregnancy will be summarized.

Long-Chain Polyunsaturated Fatty Acid Status at Birth and Development of Childhood Allergy: A Systematic Review

The associations of fetal fatty acids status to immune-related health parameters later in life are unclear. Our aim is to collect all available information on the relationship between fatty acid status at birth and allergy in childhood. Systematic literature search was performed on Ovid MEDLINE, Cochrane Library, and Embase. The search retrieved 897 articles without duplicates; 14 articles remained after excluding those that did not fit into our inclusion criteria. When the dichotomous parameter of suffering or not from allergic condition in childhood was analyzed, cord blood eicosapentaenoic acid (EPA) values proved to be significantly lower in allergic than non-allergic children in four comparisons from three studies. When the linear parameters of odds ratios and relative risks for allergy were taken into consideration, high cord blood EPA, but also high docosahexaenoic acid (DHA) and high total n-3 long-chain polyunsaturated fatty acid values were associated to clinically relevant reduction (at least 38%) in eight comparisons from five studies. Within the cord blood samples, higher EPA, docosapentaenoic acid, and DHA values were significantly and negatively associated in eight correlation analyses from three studies with laboratory parameters considered to reflect allergic trait. The data reported here may provide information for defining optimal fatty acid intakes for pregnant women.

Utility of the Specialized Pro-Resolving Mediators as Diagnostic and Prognostic Biomarkers in Disease

A precision medicine approach is widely acknowledged to yield more effective therapeutic strategies in the treatment of patients with chronic inflammatory conditions than the prescriptive paradigm currently utilized in the management and treatment of these patients. This is because such an approach will take into consideration relevant factors including the likelihood that a patient will respond to given therapeutics based on their disease phenotype. Unfortunately, the application of this precision medicine paradigm in the daily treatment of patients has been greatly hampered by the lack of robust biomarkers, in particular biomarkers for determining early treatment responsiveness. Lipid mediators are central in the regulation of host immune responses during both the initiation and resolution of inflammation. Amongst lipid mediators, the specialized pro-resolving mediators (SPM) govern immune cells to promote the resolution of inflammation. These autacoids are produced via the stereoselective conversion of essential fatty acids to yield molecules that are dynamically regulated during inflammation and exert potent immunoregulatory activities. Furthermore, there is an increasing appreciation for the role that these mediators play in conveying the biological actions of several anti-inflammatory therapeutics, including statins and aspirin. Identification and quantitation of these mediators has traditionally been achieved using hyphenated mass spectrometric techniques, primarily liquid-chromatography tandem mass spectrometry. Recent advances in the field of chromatography and mass spectrometry have increased both the robustness and the sensitivity of this approach and its potential deployment for routine clinical diagnostics. In the present review, we explore the evidence supporting a role for specific SPM as potential biomarkers for patient stratification in distinct disease settings together with methodologies employed in the identification and quantitation of these autacoids.

Long-Chain Polyunsaturated Fatty Acids (LCPUFAs) and the Developing Immune System: A Narrative Review

The immune system is complex: it involves many cell types and numerous chemical mediators. An immature immune response increases susceptibility to infection, whilst imbalances amongst immune components leading to loss of tolerance can result in immune-mediated diseases including food allergies. Babies are born with an immature immune response. The immune system develops in early life and breast feeding promotes immune maturation and protects against infections and may protect against allergies. The long-chain polyunsaturated fatty acids (LCPUFAs) arachidonic acid (AA) and docosahexaenoic acid (DHA) are considered to be important components of breast milk. AA, eicosapentaenoic acid (EPA) and DHA are also present in the membranes of cells of the immune system and act through multiple interacting mechanisms to influence immune function. The effects of AA and of mediators derived from AA are often different from the effects of the n-3 LCPUFAs (i.e., EPA and DHA) and of mediators derived from them. Studies of supplemental n-3 LCPUFAs in pregnant women show some effects on cord blood immune cells and their responses. These studies also demonstrate reduced sensitisation of infants to egg, reduced risk and severity of atopic dermatitis in the first year of life, and reduced persistent wheeze and asthma at ages 3 to 5 years, especially in children of mothers with low habitual intake of n-3 LCPUFAs. Immune markers in preterm and term infants fed formula with AA and DHA were similar to those in infants fed human milk, whereas those in infants fed formula without LCPUFAs were not. Infants who received formula plus LCPUFAs (both AA and DHA) showed a reduced risk of allergic disease and respiratory illness than infants who received standard formula. Studies in which infants received n-3 LCPUFAs report immune differences from controls that suggest better immune maturation and they show lower risk of allergic disease and respiratory illness over the first years of life. Taken together, these findings suggest that LCPUFAs play a role in immune development that is of clinical significance, particularly with regard to allergic sensitisation and allergic manifestations including wheeze and asthma.

Adipose tissue development and lipid metabolism in the human fetus: The 2020 perspective focusing on maternal diabetes and obesity

During development, the human fetus accrues the highest proportion of fat of all mammals. Precursors of fat lobules can be found at week 14 of pregnancy. Thereafter, they expand, filling with triacylglycerols during pregnancy. The resultant mature lipid-filled adipocytes emerge from a developmental programme of embryonic stem cells, which is regulated differently than adult adipogenesis. Fetal triacylglycerol synthesis uses glycerol and fatty acids derived predominantly from glycolysis and lipogenesis in liver and adipocytes. The fatty acid composition of fetal adipose tissue at the end of pregnancy shows a preponderance of palmitic acid, and differs from the mother. Maternal diabetes mellitus does not influence this fatty acid profile. Glucose oxidation is the main source of energy for the fetus, but mitochondrial fatty acid oxidation also contributes. Indirect evidence suggests the presence of lipoprotein lipase in fetal adipose tissue. Its activity may be increased under hyperinsulinemic conditions as in maternal diabetes mellitus and obesity, thereby contributing to increased triacylglycerol deposition found in the newborns of such pregnancies. Fetal lipolysis is low. Changes in the expression of genes controlling metabolism in fetal adipose tissue appear to contribute actively to the increased neonatal fat mass found in diabetes and obesity. Many of these processes are under endocrine regulation, principally by insulin, and show sex-differences. Novel fatty acid derived signals such as oxylipins are present in cord blood with as yet undiscovered function. Despite many decades of research on fetal lipid deposition and metabolism, many key questions await answers.

Eicosapentaenoic and docosahexaenoic acid derived specialised pro-resolving mediators: Concentrations in humans and the effects of age, sex, disease and increased omega-3 fatty acid intake

Although inflammation has a physiological role, unrestrained inflammation can be detrimental, causing tissue damage and disease. Under normal circumstances inflammation is self-limiting with induction of active resolution processes. Central to these is the generation of specialised pro-resolving lipid mediators (SPMs) from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These include resolvins, protectins and maresins whose activities have been well described in cell and animal models. A number of SPMs have been reported in plasma or serum in infants, children, healthy adults and individuals with various diseases, as well as in human sputum, saliva, tears, breast milk, urine, synovial fluid and cerebrospinal fluid and in human adipose tissue, skeletal muscle, hippocampus, skin, placenta, lymphoid tissues and atherosclerotic plaques. Differences in SPM concentrations have been reported between health and disease, as would be expected. However, sometimes SPM concentrations are lower in disease and sometimes they are higher. Human studies report that plasma or serum concentrations of some SPMs can be increased by increasing intake of EPA and DHA. However, the relationship of specific intakes of EPA and DHA to enhancement in the appearance of specific SPMs is not clear and needs a more thorough investigation. This is important because of the potential for EPA and DHA to be used more effectively in prevention and treatment of inflammatory conditions. If generation of SPMs represents an important mechanism of action of EPA and DHA, then more needs to be known about the most effective strategies by which EPA and DHA can increase SPM concentrations.

Biosynthetic metabolomes of cysteinyl-containing immunoresolvents

Resolution of inflammation is an active process regulated by specialized proresolving mediators where we identified 3 new pathways producing allylic epoxide-derived mediators that stimulate regeneration [i.e., peptido-conjugates in tissue regeneration (CTRs)]. Here, using self-limited Escherichia coli peritonitis in mice, we identified endogenous maresin (MaR) CTR (MCTR), protectin (PD) CTR (PCTR), and resolvin CTR in infectious peritoneal exudates and distal spleens, as well as investigated enzymes involved in their biosynthesis. PCTRs were identified to be temporally regulated in peritoneal exudates and spleens. PCTR1 and MCTR1 were each produced by human recombinant leukotriene (LT) C₄ synthase (LTC₄S) and glutathione S-transferases (GSTs) [microsomal GST (mGST)2, mGST3, and GST-μ (GSTM)4] from their epoxide precursors [16S,17S-epoxy-PD (ePD) and 13S,14S-epoxy-MaR (eMaR)], with preference for GSTM4. Both eMaR and ePD inhibited LTB₄ production by LTA₄ hydrolase. LTC₄S, mGST2, mGST3, and GSTM4 were each expressed in human M1- and M2-like macrophages where LTC₄S inhibition increased CTRs. Finally, PCTR1 showed potent analgesic action. These results demonstrate CTR biosynthesis in mouse peritonitis, human spleens, and human macrophages, as well as identification of key enzymes in these pathways. Moreover, targeting LTC₄S increases CTR metabolomes, giving a new strategy to stimulate resolution and tissue regeneration.-Jouvene, C. C., Shay, A. E., Soens, M. A., Norris, P. C., Haeggström, J. Z., Serhan, C. N. Biosynthetic metabolomes of cysteinyl-containing immunoresolvents.

Update on oxidative stress and inflammation in pregnant women, unborn children (nasciturus), and newborns - Nutritional and dietary effects

The scientific background of perinatal pathology, regarding both mother and offspring, from the lipidomic perspective, has highlighted the possibility of identifying new, promising clinical markers of oxidative stress and inflammation, closely related to the normal development of unborn and newborn children, together with their application. In this regard, in recent years, significant advances have been achieved, assisted by both newly developed analytical tools and basic knowledge on the biological implications of oxylipins. Hence, in the light of this recent progress, this review aims to provide an update on the relevance of human oxylipins during pregnancy and in the unborn and newborn child, covering two fundamental aspects. Firstly, the evidence from human clinical studies and dietary intervention trials will be used to shed light on the extent to which dietary supplementation can modulate the lipidomic markers of oxidative stress and inflammation in the perinatal state, emphasizing the role of the placenta and metabolic disturbances in the mother and fetus. The second part of this article comprises a review of existing data on specific pathophysiological aspects of human reproduction, in relation to lipidomic markers in pregnant women, unborn children, and newborn children. The information reviewed here evidences the current opportunity to correct reproductive disturbances, in the framework of lipidomics, by fine-tuning dietary interventions.

Childhood adversity, mental health, and oxidative stress: A pilot study

Childhood adversity is a potent risk factor for mental health conditions via disruptions to stress response systems. Dysregulations in oxidative stress systems have been associated with both childhood adversity and several psychological disorders (e.g., major depressive disorder) in adult populations. However, few studies have examined associations between childhood adversity, oxidative stress, and mental health in pediatric populations. Childhood adversity (Adverse Childhood Events [ACE]), oxidative stress [F2t-isoprostanes (IsoPs)], and mental health pathology were assessed in 50 adolescent females recruited primarily through the Department of Youth Services. Standard ordinary least squares regression models were run co-varying for age, race/ethnicity, adolescent nicotine use, study condition, and parent history of ACEs. Adolescents who reported experiencing four or more ACEs had significantly elevated IsoP levels. Further, internalizing symptom scores across diagnoses were significantly associated with elevated IsoPs, whereas no externalizing symptoms scores, except Attention Deficit Hyperactivity Disorder, were related to altered oxidative stress. Results indicate that IsoPs may be a global marker of childhood adversity and mental health symptomatology, particularly within internalizing symptom domains. A limitation is that body mass index was not collected for this sample. Future studies are needed to replicate and extend these findings in larger, more diverse samples.

Identification of specialized pro-resolving mediator clusters from healthy adults after intravenous low-dose endotoxin and omega-3 supplementation: a methodological validation

Specialized pro-resolving mediator(s) (SPMs) are produced from the endogenous ω-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and accelerate resolution of acute inflammation. We identified specific clusters of SPM in human plasma and serum using LC-MS/MS based lipid mediator (LM) metabololipidomics in two separate laboratories for inter-laboratory validation. The human plasma cluster consisted of resolvin (Rv)E1, RvD1, lipoxin (LX)B₄, 18-HEPE, and 17-HDHA, and the human serum cluster consisted of RvE1, RvD1, AT-LXA₄, 18-HEPE, and 17-HDHA. Human plasma and serum SPM clusters were increased after ω-3 supplementation (triglyceride dietary supplements or prescription ethyl esters) and low dose intravenous lipopolysaccharide (LPS) challenge. These results were corroborated by parallel determinations with the same coded samples in a second, separate laboratory using essentially identical metabololipidomic operational parameters. In these healthy subjects, two ω-3 supplementation protocols (Study A and Study B) temporally increased the SPM cluster throughout the endotoxin-challenge time course. Study A and Study B were randomized and Study B also had a crossover design with placebo and endotoxin challenge. Endotoxin challenge temporally regulated lipid mediator production in human serum, where pro-inflammatory eicosanoid (prostaglandins and thromboxane) concentrations peaked by 8 hours post-endotoxin and SPMs such as resolvins and lipoxins initially decreased by 2 h and were then elevated at 24 hours. In healthy adults given ω-3 supplementation, the plasma concentration of the SPM cluster (RvE1, RvD1, LXB₄, 18-HEPE, and 17-HDHA) peaked at two hours post endotoxin challenge. These results from two separate laboratories with the same samples provide evidence for temporal production of specific pro-resolving mediators with ω-3 supplementation that together support the role of SPM in vivo in inflammation-resolution in humans.

Resolvins in inflammation: emergence of the pro-resolving superfamily of mediators

Countless times each day, the acute inflammatory response protects us from invading microbes, injuries, and insults from within, as in surgery-induced tissue injury. These challenges go unnoticed because they are self-limited and naturally resolve without progressing to chronic inflammation. Peripheral blood markers of inflammation are present in many common diseases, including inflammatory bowel disease, cardiovascular disease, neurodegenerative disease, and cancer. While acute inflammation is protective, excessive swarming of neutrophils amplifies collateral tissue damage and inflammation. Hence, understanding the mechanisms that control the resolution of acute inflammation provides insight into preventing and treating inflammatory diseases in multiple organs. This Review focuses on the resolution phase of inflammation with identification of specialized pro-resolving mediators (SPMs) that involve three separate biosynthetic and potent mediator families, which are defined using the first quantitative resolution indices to score this vital process. These are the resolvins, protectins, and maresins: bioactive metabolomes that each stimulate self-limited innate responses, enhance innate microbial killing and clearance, and are organ-protective. We briefly address biosynthesis of SPMs and their activation of endogenous resolution programs as terrain for new therapeutic approaches that are not, by definition, immunosuppressive, but rather new immunoresolvent therapies.