The role of specialized pro-resolving mediators in maternal-fetal health

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.

Resolvins Lipid Mediators: Potential Therapeutic Targets in Alzheimer and Parkinson Disease

Inflammation and resolution are highly programmed processes involving a plethora of immune cells. Lipid mediators synthesized from arachidonic acid metabolism play a pivotal role in orchestrating the signaling cascades in the game of inflammation. The majority of the studies carried out so far on inflammation were aimed at inhibiting the generation of inflammatory molecules, whereas recent research has shifted more towards understanding the resolution of inflammation. Owing to chronic inflammation as evident in neuropathophysiology, the resolution of inflammation together with the class of lipid mediators actively involved in its regulation has attracted the attention of the scientific community as therapeutic targets. Both omega-three polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoic acid, orchestrate a vital regulatory role in inflammation development. Resolvins derived from these fatty acids comprise the D-and E-series resolvins. A growing body of evidence using in vitro and in vivo models has revealed the pro-resolving and anti-inflammatory potential of resolvins. This systematic review sheds light on the synthesis, specialized receptors, and resolution of inflammation mediated by resolvins in Alzheimer's and Parkinson's disease.

Inflammation and oxidative stress as mediators of the impacts of environmental exposures on human pregnancy: Evidence from oxylipins

Inflammation and oxidative stress play major roles in healthy and pathological pregnancy. Environmental exposure to chemical pollutants may adversely affect maternal and fetal health in pregnancy by dysregulating these critical underlying processes of inflammation and oxidative stress. Oxylipins are bioactive lipids that play a major role in regulating inflammation and increasing lines of evidence point towards an importance in pregnancy. The biosynthetic production of oxylipins requires oxygenation of polyunsaturated fatty acids, which can occur through several well-characterized enzymatic and nonenzymatic pathways. This review describes the state of the science of epidemiologic evidence on oxylipin production in pregnancy and its association with 1) key pregnancy outcomes and 2) environmental exposures. We searched PubMed for studies of pregnancy that measured one or more oxylipin analytes during pregnancy or delivery. We evaluated oxylipin associations with three categories of adverse pregnancy outcomes, including preeclampsia, preterm birth, and fetal growth restriction, along with several categories of environmental pollutants. The majority of studies evaluated one to two oxylipins, most of which focused on oxylipins produced from nonenzymatic processes of oxidative stress. However, an increasing number of recent studies have leveraged technological advancements to profile a large number of oxylipins produced from distinct biosynthetic pathways. Although the literature indicated robust evidence that oxylipins produced via nonenzymatic pathways are associated with pregnancy outcomes and environmental exposures, evidence for enzymatically produced oxylipins showed that associations may differ between biosynthetic pathways. Along with summarizing this evidence, we review promising therapeutic options to regulate oxylipin production and provide a set of recommendations for future epidemiologic studies in these research areas. Further evidence is needed to improve our understanding of how oxylipins may act as key biological mediators for the adverse effects of environmental pollutants on pregnancy outcomes.

Oxidation of Polyunsaturated Fatty Acids as a Promising Area of Research in Infertility

In this review, the role of fatty acids (FA) in human pathological conditions, infertility in particular, was considered. FA and FA-derived metabolites modulate cell membrane composition, membrane lipid microdomains and cell signaling. Moreover, such molecules are involved in cell death, immunological responses and inflammatory processes. Human health and several pathological conditions are specifically associated with both dietary and cell membrane lipid profiles. The role of FA metabolism in human sperm and spermatogenesis has recently been investigated. Cumulative findings indicate F₂ isoprostanes (oxygenated products from arachidonic acid metabolism) and resolvins (lipid mediators of resolution of inflammation) as promising biomarkers for the evaluation of semen and follicular fluid quality. Advanced knowledge in this field could lead to new scenarios in the treatment of infertility.

Resolvins' Obesity-Driven Deficiency: The Implications for Maternal-Fetal Health

Since pregnancy is already characterized by mild but significant inflammatory activity in physiological conditions, when complicated by obesity the probability of a persistent inflammatory state increases, with consequent multiple repercussions that add up to the complications associated with acute inflammation. In this context, the role of resolvins, specialized pro-resolving mediators (SPMs), deriving from omega-3 essential fatty acids, may be crucial. Indeed, differential production in numerous high-risk conditions associated with both childbirth and neonatal health, the correlation between maternal omega-3 intake and resolvin concentrations in maternal blood and at the placental level, and the high values found in breast milk in the first month of breastfeeding, are some of the most important hallmarks of these autacoids. In addition, a growing body of scientific evidence supports the lack of SPMs, at the level of immune-metabolic tissues, in the case of obesity. Furthermore, the obesity-related lack of SPMs seems to be decisive in the context of the current outbreak of COVID-19, as it appears to be one of the causes associated with the higher incidence of complications and negative outcomes of SARS-CoV-2 infection. The usefulness of metabolomics in this field appears clear, given that through the metabolome it is possible to observe the numerous and complex interactions between the mother, the placenta and the fetus in order to identify specific biomarkers useful in the prediction, diagnosis and monitoring of the various obstetric conditions. However, further investigations are needed in order to evaluate the possible use of some resolvins as biomarkers of maternal–fetal outcomes but also to establish adequate integration values in pregnant women with omega-3 fatty acids or with more active derivatives that guarantee optimal SPM production under risky conditions.

Fatty acids in normal and pathological pregnancies

Long chain fatty acids, namely omega-3 and omega-6, are essential fatty acids and are necessary for proper pregnancy progression and fetal growth and development. Maternal fatty acid consumption and release of fatty acids from lipid stores provide increased availability of fatty acids for the placenta to transport to the growing fetus. Both omega-3 and omega-6 fatty acids are then utilized for generation of signaling molecules, such as eicosanoids, and for promoting of growth and developmental, most notably in the nervous system. Perturbations in fatty acid concentration and fatty acid signaling have been implicated in three major pregnancy complications - gestational diabetes, preeclampsia, and preterm birth. In this review we discuss the growing literature surrounding the role of fatty acids in normal and pathological pregnancies. Differences in maternal, placental, and fetal fatty acids and molecular regulation of fatty acid signaling and transport are presented. A look into novel fatty acid-based therapies for each of the highlighted disorders are discussed, and may present exciting bench to bedside alternatives to traditional pharmacological intervention.

Role of specialized pro-resolving lipid mediators in pulmonary inflammation diseases: mechanisms and development

Inflammation is an essential mechanism of various diseases. The development and resolution of inflammation are complex immune-modulation processes which induce the involvement of various types of immune cells. Specialized pro-resolving lipid mediators (SPMs) have been demonstrated to be signaling molecules in inflammation. SPMs are involved in the pathophysiology of different diseases, especially respiratory diseases, including asthma, pneumonia, and chronic obstructive pulmonary disease. All of these diseases are related to the inflammatory response and its persistence. Therefore, a deeper understanding of the mechanisms and development of inflammation in respiratory disease, and the roles of the SPM family in the resolution process, might be useful in the quest for novel therapies and preventive measures for pulmonary diseases.

Intrauterine Transfer of Polyunsaturated Fatty Acids in Mother-Infant Dyads as Analyzed at Time of Delivery

Polyunsaturated fatty acids (PUFAs) are essential for fetal development, and intrauterine transfer is the only supply of PUFAs to the fetus. The prevailing theory of gestational nutrient transfer is that certain nutrients (including PUFAs) may have prioritized transport across the placenta. Numerous studies have identified correlations between maternal and infant fatty acid concentrations; however, little is known about what role maternal PUFA status may play in differential intrauterine nutrient transfer. Twenty mother–infant dyads were enrolled at delivery for collection of maternal and umbilical cord blood, and placental tissue samples. Plasma concentrations of PUFAs were assessed using gas chromatography (GC-FID). Intrauterine transfer percentages for each fatty acid were calculated as follows: ((cord blood fatty acid level/maternal blood fatty acid level) × 100). Kruskal–Wallis tests were used to compare transfer percentages between maternal fatty acid tertile groups. A p-value < 0.05 was considered significant. There were statistically significant differences in intrauterine transfer percentages of arachidonic acid (AA) (64% vs. 65% vs. 45%, p = 0.02), eicosapentaenoic acid (EPA) (41% vs. 19% vs. 17%, p = 0.03), and total fatty acids (TFA) (27% vs. 26% vs. 20%, p = 0.05) between maternal plasma fatty acid tertiles. Intrauterine transfer percentages of AA, EPA, and TFA were highest in the lowest tertile of respective maternal fatty acid concentration. These findings may indicate that fatty acid transfer to the fetus is prioritized during gestation even during periods of maternal nutritional inadequacy.

Exploring the role of LC-PUFA metabolism in pregnancy complications

Maternal nutrition during pregnancy plays a significant role in growth and development of the placenta and influencing pregnancy outcome. Suboptimal nutritional status during early gestational period compromises the normal course of pregnancy leading to adverse maternal and fetal outcomes. Omega-3 and omega-6 long chain polyunsaturated fatty acids (LC-PUFA) are important for the growth and development of the placenta. Maternal fatty acids and their metabolites influence the normal course of pregnancy by regulating cell growth and development, cell signaling, regulate angiogenesis, modulate inflammatory responses and influence various structural and functional processes. Alterations in LC-PUFA and their metabolites may result in inadequate spiral artery remodeling or placental angiogenesis leading to structural and functional deficiency of the placenta which contributes to several pregnancy complications like preeclampsia, gestational diabetes mellitus, intrauterine growth restriction, and results in adverse birth outcomes. In this review, we summarize studies examining the role of fatty acids and their metabolites in pregnancy. We also discuss the possible molecular mechanisms through which LC-PUFA influences placental growth and development. Studies have demonstrated that omega-3 fatty acid supplementation lowers the incidence of preterm births, but its effect on reducing pregnancy complications are inconclusive.

Low Omega-3 intake is associated with high rates of depression and preterm birth on the country level

Low circulating levels of long chain omega-3 polyunsaturated fatty acids (LC omega-3 PUFA) have been linked to major depressive disorder (MDD) and preterm birth (PTB), and prenatal depression associates with PTB. We therefore hypothesized that low Omega-3 intake would associate with higher MDD and PTB rates on the country-level. To test this hypothesis, we obtained country-level estimates for omega-3 intake, MDD prevalence, PTB rate, and per capita income for 184 countries in 2010. We then estimated the LC omega-3 PUFA levels that these intakes produce by accounting for direct consumption and the endogenous conversion of ingested plant-based precursors. Penalized splines indicated that MDD and PTB rates decreased linearly with increasing LC omega-3 PUFA, up to ~ 1000 mg/day for MDD and up to ~ 550 mg/day for PTB. Adjusted linear regression models below these thresholds revealed that a one standard deviation increase in LC omega-3 PUFA (380 mg/day) was associated with an MDD decrease of 5 cases/1000 people and a PTB decrease of 15 cases/1000 livebirths. In light of the extensive prior evidence on the individual-level, these findings indicate that low intake of LC omega-3 PUFA and its precursors may be elevating MDD and PTB rates in 85% of the countries studied.

Fat-soluble nutrients and Omega-3 fatty acids as modifiable factors influencing preterm birth risk

Preterm birth is a leading cause of child morbidity and mortality, so strategies to reduce early birth must remain a priority. One key approach to enhancing birth outcomes is improving maternal dietary intake. Therefore, the purpose of this review is to discuss mechanisms on perinatal status of fat-soluble nutrients (carotenoids, retinol, tocopherols) and omega-3 fatty acids and how they impact risk for preterm birth. Literature review demonstrates that maternal dietary intake and biological (blood and placental tissue) levels of fat-soluble nutrients during pregnancy may provide antioxidative, anti-inflammatory, and immunomodulatory health benefits. Omega-3 fatty acids also promote increased production of specialized pro-resolving mediators, subsequently mediating inflammation resolution. Combined effects of these nutrients support appropriate placental organogenesis and function. Consequently, fat-soluble nutrients and omega-3 fatty acids serve as strong influencers for preterm birth risk. As dietary intake remains a modifiable factor, future intervention would benefit from a focus on optimizing perinatal status of these specific nutrients.

Experimental drugs for the inhibition of preterm labor

INTRODUCTION

Preterm birth is the leading cause of neonatal morbidity and mortality globally and poses a substantial economic burden. Consequently, there is a need for the identification of therapeutic targets and novel experimental drugs for the inhibition of preterm labor to improve neonatal outcomes.

AREAS COVERED

The authors review the pathophysiology of labor and the inflammatory pathways underpinning it. The interruption of these pathways forms the basis of therapeutic targets to inhibit preterm labor. Current drugs available for the treatment of preterm labor are reviewed, followed by experimental drugs including toll-like receptor 4 (TLR-4) antagonists, cytokine suppressive anti-inflammatory drugs (CSAIDs), N-acetyl cysteine (NAC), Sulfasalazine (SSZ), tumor necrosis factor-alpha (TNF-α) antagonists, interleukin-1 receptor (IL-1) inhibitors, omega-3 polyunsaturated fatty acids and lipid metabolites, and the polyphenols.

EXPERT OPINION

A number of new therapeutic strategies for the prevention of preterm labor are being investigated. These have the potential to improve neurodevelopmental outcomes and survival in babies born preterm, reducing the economic and healthcare costs of caring for the complex needs of these children in the immediate and long term. It is likely that over the next decade there will be a new treatment option that targets the pathological inflammatory processes involved in preterm labor.

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.

Pro-Resolving Lipid Mediators in the Pathophysiology of Asthma

Asthma is one of the most important medical and social problems of our time due to the prevalence and the complexity of its treatment. Chronic inflammation that is characteristic of asthma is accompanied by bronchial obstruction, which involves various lipid mediators produced from n-6 and n-3 polyunsaturated fatty acids (PUFAs). The review is devoted to modern ideas about the PUFA metabolites—eicosanoids (leukotrienes, prostaglandins, thromboxanes) and specialized pro-resolving lipid mediators (SPMs) maresins, lipoxins, resolvins, protectins. The latest advances in clinical lipidomics for identifying and disclosing the mechanism of synthesis and the biological action of SPMs have been given. The current views on the peculiarities of the inflammatory reaction in asthma and the role of highly specialized metabolites of arachidonic, eicosapentaenoic and docosahexaenoic acids in this process have been described. The possibility of using SPMs as therapeutic agents aimed at controlling the resolution of inflammation in asthma is discussed.

Omega-3 Fatty Acid Supplementation, Pro-Resolving Mediators, and Clinical Outcomes in Maternal-Infant Pairs

Omega (n)-3 fatty acids are vital to neonatal maturation, and recent investigations reveal n-3 fatty acids serve as substrates for the biosynthesis of specialized pro-resolving lipid mediators (SPM) that have anti-inflammatory and immune-stimulating effects. The role SPM play in the protection against negative maternal-fetal health outcomes is unclear, and there are no current biomarkers of n-3 fatty acid sufficiency. We sought to ascertain the relationships between n-3 fatty acid intake, SPM levels, and maternal-fetal health outcomes. We obtained n-3 fatty acid intake information from 136 mothers admitted for delivery using a food frequency questionnaire and measured docosahexaenoic acid (DHA)-derived SPMs resolvin D1 (RvD1) and RvD2 in maternal and cord plasma. We found significantly elevated SPM in maternal versus cord plasma, and increased SPM levels were associated with at-risk outcomes. We also identified that increased DHA intake was associated with elevated maternal plasma RvD1 (p = 0.03; R² = 0.18) and RvD2 (p = 0.04; R² = 0.20) in the setting of neonatal intensive care unit (NICU) admission. These findings indicate that increased n-3 fatty acid intake may provide increased substrate for the production of SPM during high-risk pregnancy/delivery conditions, and that increased maternal plasma SPM could serve as a biomarker for negative neonatal outcomes.

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.