Eicosanomic profiling reveals dominance of the epoxygenase pathway in human amniotic fluid at term in spontaneous labor

Topical Vitamin D Prevents Bone Loss and Inflammation in a Mouse Model

There is a strong association between vitamin D levels and periodontal disease based on numerous epidemiological studies. We have previously shown that experimental deficiency of serum vitamin D in mice leads to gingival inflammation and alveolar bone loss. Treatment of cultured oral epithelial cells with the active form of vitamin D, 1,25(OH)2 vitamin D3 (1,25(OH)2D3), inhibits the extracellular growth and intracellular invasion of bacteria associated with periodontal disease. Maintenance of periodontal health may be due in part to the anti-inflammatory activities of vitamin D. Furthermore, this hormone can induce the expression of an antimicrobial peptide in cultured oral epithelial cells. We have shown that oral epithelial cells are capable of converting inactive vitamin D to the active form, suggesting that topical treatment of the oral epithelium with inactive vitamin D could prevent the development of periodontitis. We subjected mice to ligature-induced periodontitis (LIP), followed by daily treatment with inactive vitamin D or 1,25(OH)2D3. Treatment with both forms led to a reduction in ligature-induced bone loss and inflammation. Gingival tissues obtained from vitamin D-treated LIP showed production of specialized proresolving mediators (SPM) of inflammation. To examine the mechanism, we demonstrated that apical treatment of 3-dimensional cultures of primary gingival epithelial cells with vitamin D prevented lipopolysaccharide-induced secretion of proinflammatory cytokines and led to a similar production of SPM. Analysis of the oral microbiome of the mice treated with vitamin D showed significant changes in resident bacteria, which reflects a shift toward health-associated species. Together, our results show that topical treatment of oral tissues with inactive vitamin D can lead to the maintenance of periodontal health through the regulation of a healthy microbiome and the stimulation of resolution of inflammation. This strongly supports the development of a safe and effective vitamin D-based topical treatment or preventive agent for periodontal inflammation and disease.

Neuroinflammation is dependent on sex and ovarian hormone presence following acute woodsmoke exposure

Woodsmoke (WS) exposure is associated with significant health-related sequelae. Different populations can potentially exhibit varying susceptibility, based on endocrine phenotypes, to WS and investigating neurological impacts following inhaled WS is a growing area of research. In this study, a whole-body inhalation chamber was used to expose both male and female C57BL/6 mice (n = 8 per group) to either control filtered air (FA) or acute WS (0.861 ± 0.210 mg/m3) for 4 h/d for 2 days. Neuroinflammatory and lipid-based biological markers were then assessed. In a second set of studies, female mice were divided into two groups: one group was ovariectomized (OVX) to simulate an ovarian hormone-deficient state (surgical menopause), and the other underwent Sham surgery as controls, to mechanistically assess the impact of ovarian hormone presence on neuroinflammation following FA and acute WS exposure to simulate an acute wildfire episode. There was a statistically significant impact of sex (P ≤ 0.05) and statistically significant interactions between sex and treatment in IL-1β, CXCL-1, TGF-β, and IL-6 brain relative gene expression. Hippocampal and cortex genes also exhibited significant changes in acute WS-exposed Sham and OVX mice, particularly in TGF-β (hippocampus) and CCL-2 and CXCL-1 (cortex). Cortex GFAP optical density (OD) showed a notable elevation in male mice exposed to acute WS, compared to the control FA. Sham and OVX females demonstrated differential GFAP expression, depending on brain region. Overall, targeted lipidomics in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) serum and brain lipids demonstrated more significant changes between control FA and acute WS exposure in female mice, compared to males. In summary, male and female mice show distinct neuroinflammatory markers in response to acute WS exposure. Furthermore, ovarian hormone deficiency may impact the neuroinflammatory response following an acute WS event.

Vaginal Progesterone to Prevent Spontaneous Preterm Birth in Women With a Sonographic Short Cervix: The Story of the PREGNANT Trial

The PREGNANT trial was a randomized, placebo-controlled, multicenter trial designed to determine the efficacy and safety of vaginal progesterone (VP) to reduce the risk of birth < 33 weeks and of neonatal complications in women with a sonographic short cervix (10 to 20 mm) in the mid-trimester (19 to 23 6/7 wk). Patients allocated to receive VP had a 45% lower rate of preterm birth (8.9% vs 16.1%; relative risk = 0.55; 95% CI: 0.33-0.92). Neonates born to mothers allocated to VP had a 60% reduction in the rate of respiratory distress syndrome. This article reviews the background, design, execution, interpretation, and impact of the PREGNANT Trial.

Loss of flavin-containing monooxygenase 3 modulates dioxin-like polychlorinated biphenyl 126-induced oxidative stress and hepatotoxicity

Dioxin-like pollutants (DLPs), such as polychlorinated biphenyl 126 (PCB 126), are synthetic chemicals classified as persistent organic pollutants. They accumulate in adipose tissue and have been linked to cardiometabolic disorders, including fatty liver disease. The toxicity of these compounds is associated with activation of the aryl hydrocarbon receptor (Ahr), leading to the induction of phase I metabolizing enzyme cytochrome P4501a1 (Cyp1a1) and the subsequent production of reactive oxygen species (ROS). Recent research has shown that DLPs can also induce the xenobiotic detoxification enzyme flavin-containing monooxygenase 3 (FMO3), which plays a role in metabolic homeostasis. We hypothesized whether genetic deletion of Fmo3 could protect mice, particularly in the liver, where Fmo3 is most inducible, against PCB 126 toxicity. To test this hypothesis, male C57BL/6 wild-type (WT) mice and Fmo3 knockout (Fmo3 KO) mice were exposed to PCB 126 or vehicle (safflower oil) during a 12-week study, at weeks 2 and 4. Various analyses were performed, including hepatic histology, RNA-sequencing, and quantitation of PCB 126 and F2-isoprostane concentrations. The results showed that PCB 126 exposure caused macro and microvesicular fat deposition in WT mice, but this macrovesicular fatty change was absent in Fmo3 KO mice. Moreover, at the pathway level, the hepatic oxidative stress response was significantly different between the two genotypes, with the induction of specific genes observed only in WT mice. Notably, the most abundant F2-isoprostane, 8-iso-15-keto PGE2, increased in WT mice in response to PCB 126 exposure. The study's findings also demonstrated that hepatic tissue concentrations of PCB 126 were higher in WT mice compared to Fmo3 KO mice. In summary, the absence of FMO3 in mice led to a distinctive response to dioxin-like pollutant exposure in the liver, likely due to alterations in lipid metabolism and storage, underscoring the complex interplay of genetic factors in the response to environmental toxins.

Resolvin E1 improves efferocytosis and rescues severe aplastic anemia in mice

Severe aplastic anemia (SAA) is a rare, fatal disease characterized by severe cytopenias and loss of hematopoietic stem cells (HSCs). Immune-mediated destruction and inflammation are known drivers of SAA, however, the underlying mechanisms driving persistent inflammation are unknown. Current treatments for SAA rely on immunosuppressive therapies or HSC transplantation, however, these treatments are not always effective. Using an established mouse model of SAA, we observed a significant increase in apoptotic cells within the bone marrow (BM) and impaired efferocytosis in SAA mice, relative to radiation controls. Single-cell transcriptomic analysis revealed heterogeneity among BM monocytes and unique populations emerged during SAA characterized by increased inflammatory signatures and significantly increased expression of Sirpa and Cd47. CD47, a "don't eat me" signal, was increased on both live and apoptotic BM cells, concurrent with markedly increased expression of signal regulatory protein alpha (SIRPα) on monocytes. Functionally, SIRPα blockade improved cell clearance and reduced accumulation of CD47-positive apoptotic cells. Lipidomic analysis revealed a reduction in the precursors of specialized pro-resolving lipid mediators (SPMs) and increased prostaglandins in the BM during SAA, indicative of impaired inflammation resolution. Specifically, 18-HEPE, a precursor of E-series resolvins, was significantly reduced in SAA-induced mice relative to radiation controls. Treatment of SAA mice with Resolvin E1 (RvE1) improved efferocytic function, BM cellularity, platelet output, and survival. Our data suggest that impaired efferocytosis and inflammation resolution contributes to SAA progression and demonstrate that SPMs, such as RvE1, offer new and/or complementary treatments for SAA that do not rely on immune suppression.

Inflammation, lipid dysregulation, and transient receptor potential cation channel subfamily V member 4 signaling perpetuate chronic vulvar pain

ABSTRACT

Localized provoked vulvodynia is characterized by chronic vulvar pain that disrupts every aspect of the patient's life. Pain is localized to the vulvar vestibule, a specialized ring of tissue immediately surrounding the vaginal opening involved in immune defense. In this article, we show inflammation is the critical first step necessary for the generation of pain signals in the vulva. Inflammatory stimuli alone or combined with the transient receptor potential cation channel subfamily V member 4 (TRPV4) agonist 4α-phorbol 12,13-didecanoate stimulate calcium flux into vulvar fibroblast cells. Activity is blocked by the TRPV4 antagonist HC067047, denoting specificity to TRPV4. Using lipidomics, we found pro-resolving lipids in the vulvar vestibule were dysregulated, characterized by a reduction in pro-resolving mediators and heightened production of inflammatory mediators. We demonstrate specialized pro-resolving mediators represent a potential new therapy for vulvar pain, acting on 2 key parts of the disease mechanism by limiting inflammation and acutely inhibiting TRPV4 signaling.

Modulating the sEH/EETs Axis Restrains Specialized Proresolving Mediator Impairment and Regulates T Cell Imbalance in Experimental Periodontitis

Epoxyeicosatrienoic acids (EETs) and other epoxy fatty acids are short-acting lipids involved in resolution of inflammation. Their short half-life, due to its metabolism by soluble epoxide hydrolase (sEH), limits their effects. Specialized proresolving mediators (SPMs) are endogenous regulatory lipids insufficiently synthesized in uncontrolled and chronic inflammation. Using an experimental periodontitis model, we pharmacologically inhibited sEH, examining its impact on T cell activation and systemic SPM production. In humans, we analyzed sEH in the gingival tissue of periodontitis patients. Mice were treated with sEH inhibitor (sEHi) and/or EETs before ligature placement and treated for 14 d. Bone parameters were assessed by microcomputed tomography and methylene blue staining. Blood plasma metabololipidomics were carried out to quantify SPM levels. We also determined T cell activation by reverse transcription-quantitative PCR and flow cytometry in cervical lymph nodes. Human gingival samples were collected to analyze sEH using ELISA and electrophoresis. Data reveal that pharmacological sEHi abrogated bone resorption and preserved bone architecture. Metabololipidomics revealed that sEHi enhances lipoxin A4, lipoxin B4, resolvin E2, and resolvin D6. An increased percentage of regulatory T cells over Th17 was noted in sEHi-treated mice. Lastly, inflamed human gingival tissues presented higher levels and expression of sEH than did healthy gingivae, being positively correlated with periodontitis severity. Our findings indicate that sEHi preserves bone architecture and stimulates SPM production, associated with regulatory actions on T cells favoring resolution of inflammation. Because sEH is enhanced in human gingivae from patients with periodontitis and connected with disease severity, inhibition may prove to be an attractive target for managing osteolytic inflammatory diseases.

Sustained activation of 12/15 lipoxygenase (12/15 LOX) contributes to impaired renal recovery post ischemic injury in male SHR compared to females

BACKGROUND

Acute kidney injury (AKI) due to ischemia-reperfusion (IR) is a serious and frequent complication in clinical settings, and mortality rates remain high. There are well established sex differences in renal IR, with males exhibiting greater injury following an ischemic insult compared to females. We recently reported that males have impaired renal recovery from ischemic injury vs. females. However, the mechanisms mediating sex differences in renal recovery from IR injury remain poorly understood. Elevated 12/15 lipoxygenase (LOX) activity has been reported to contribute to the progression of numerous kidney diseases. The goal of the current study was to test the hypothesis that enhanced activation of 12/15 LOX contributes to impaired recovery post-IR in males vs. females.

METHODS

13-week-old male and female spontaneously hypertensive rats (SHR) were randomized to sham or 30-minute warm bilateral IR surgery. Additional male and female SHR were randomized to treatment with vehicle or the specific 12/15 LOX inhibitor ML355 1 h prior to sham/IR surgery, and every other day following up to 7-days post-IR. Blood was collected from all rats 1-and 7-days post-IR. Kidneys were harvested 7-days post-IR and processed for biochemical, histological, and Western blot analysis. 12/15 LOX metabolites 12 and 15 HETE were measured in kidney samples by liquid chromatography-mass spectrometry (LC/MS).

RESULTS

Male SHR exhibited delayed recovery of renal function post-IR vs. male sham and female IR rats. Delayed recovery in males was associated with activation of renal 12/15 LOX, increased renal 12-HETE, enhanced endoplasmic reticulum (ER) stress, lipid peroxidation, renal cell death and inflammation compared to females 7-days post-IR. Treatment of male SHR with ML355 lowered levels of 12-HETE and resulted in reduced renal lipid peroxidation, ER stress, tubular cell death and inflammation 7-days post-IR with enhanced recovery of renal function compared to vehicle-treated IR male rats. ML355 treatment did not alter IR-induced increases in plasma creatinine in females, however, tubular injury and cell death were attenuated in ML355 treated females compared to vehicle-treated rats 7 days post-IR.

CONCLUSION

Our data demonstrate that sustained activation 12/15 LOX contributes to impaired renal recovery post ischemic injury in male and female SHR, although males are more susceptible on this mechanism than females.

Resolvin E1 improves efferocytosis and rescues severe aplastic anemia in mice

Current treatments for severe aplastic anemia (SAA) rely on hematopoietic stem cell (HSC) transplantation and immunosuppressive therapies, however these treatments are not always effective. While immune-mediated destruction and inflammation are known drivers of SAA, the underlying mechanisms that lead to persistent inflammation are unknown. Using an established mouse model of SAA, we observed a significant increase in apoptotic cells within the bone marrow (BM) and demonstrate impaired efferocytosis in SAA mice, as compared to radiation controls. Single-cell transcriptomic analysis revealed heterogeneity among BM monocytes and unique populations emerged during SAA characterized by increased inflammatory signatures and significantly increased expression of Sirpa and Cd47. CD47, a "don't eat me" signal, was increased on both live and apoptotic BM cells, concurrent with markedly increased expression of signal regulatory protein alpha (SIRPα) on monocytes. Functionally, SIRPα blockade improved cell clearance and reduced accumulation of CD47-positive apoptotic cells. Lipidomic analysis revealed a reduction in the precursors of specialized pro-resolving lipid mediators (SPMs) and increased prostaglandins in the BM during SAA, indicative of impaired inflammation resolution. Specifically, 18-HEPE, a precursor of E-series resolvins, was significantly reduced in SAA-induced mice relative to radiation controls. Treatment of SAA mice with Resolvin E1 (RvE1) improved efferocytic function, BM cellularity, platelet output, and survival. Our data suggest that impaired efferocytosis and inflammation resolution contributes to SAA progression and demonstrate that SPMs, such as RvE1, offer new and/or complementary treatments for SAA that do not rely on immune suppression.

Urinary oxidative stress biomarkers are associated with preterm birth: an Environmental Influences on Child Health Outcomes program study

BACKGROUND

Preterm birth is the leading cause of infant morbidity and mortality worldwide. Elevated levels of oxidative stress have been associated with an increased risk of delivering before term. However, most studies testing this hypothesis have been conducted in racially and demographically homogenous study populations, which do not reflect the diversity within the United States.

OBJECTIVE

We leveraged 4 cohorts participating in the Environmental Influences on Child Health Outcomes Program to conduct the largest study to date examining biomarkers of oxidative stress and preterm birth (N=1916). Furthermore, we hypothesized that elevated oxidative stress would be associated with higher odds of preterm birth, particularly preterm birth of spontaneous origin.

STUDY DESIGN

This study was a pooled analysis and meta-analysis of 4 birth cohorts spanning multiple geographic regions in the mainland United States and Puerto Rico (208 preterm births and 1708 full-term births). Of note, 8-iso-prostaglandin-F2α, 2,3-dinor-5,6-dihydro-8-iso-prostaglandin-F2α (F2-IsoP-M; the major 8-iso-prostaglandin-F2α metabolite), and prostaglandin-F2α were measured in urine samples obtained during the second and third trimesters of pregnancy. Logistic regression was used to calculate adjusted odds ratios and 95% confidence intervals for the associations between averaged biomarker concentrations for each participant and all preterm births, spontaneous preterm births, nonspontaneous preterm births (births of medically indicated or unknown origin), and categories of preterm birth (early, moderate, and late). Individual oxidative stress biomarkers were examined in separate models.

RESULTS

Approximately 11% of our analytical sample was born before term. Relative to full-term births, an interquartile range increase in averaged concentrations of F2-IsoP-M was associated with higher odds of all preterm births (odds ratio, 1.29; 95% confidence interval, 1.11-1.51), with a stronger association observed for spontaneous preterm birth (odds ratio, 1.47; 95% confidence interval, 1.16-1.90). An interquartile range increase in averaged concentrations of 8-iso-prostaglandin-F2α was similarly associated with higher odds of all preterm births (odds ratio, 1.19; 95% confidence interval, 0.94-1.50). The results from our meta-analysis were similar to those from the pooled combined cohort analysis.

CONCLUSION

Here, oxidative stress, as measured by 8-iso-prostaglandin-F2α, F2-IsoP-M, and prostaglandin-F2α in urine, was associated with increased odds of preterm birth, particularly preterm birth of spontaneous origin and delivery before 34 completed weeks of gestation.

Clinical response to EPA supplementation in patients with major depressive disorder is associated with higher plasma concentrations of pro-resolving lipid mediators

Chronic inflammation has been implicated in the pathophysiology of major depressive disorder (MDD). Activating the resolution of inflammation through ω-3 fatty acid supplementation may prove to be a successful therapeutic strategy for the treatment of MDD. Patients with MDD, body mass index >25 kg/m², and plasma high-sensitivity C-reactive protein ≥3 μg/mL (n = 61) were enrolled in a 12-week randomized trial consisting of 4 parallel arms: EPA 1, 2, and 4 g/d, and placebo. The supplement contained EPA and DHA in a 3.9:1 ratio. Depression symptoms were assessed using the IDS-C30 scale. Plasma fatty acids and pro-resolving lipid mediators (SPMs) were measured in 42 study completers at baseline and at the end of treatment by liquid chromatography/mass spectrometry. The response rate (≥50% reduction in IDS-30 score) was higher in the 4 g/d EPA arm than placebo (Cohen d = 0.53). In the 4 g/d EPA arm, responders had significantly greater increases in 18-hydroxyeicosapentaenoic acid (18-HEPE) and 13-hydroxydocosahexaenoic acid (13-HDHA) than non-responders (p < 0.05). Within the 4 g/d EPA arm, the increase in 18-HEPE was significantly associated with reductions in plasma hs-CRP concentrations (p < 0.05) and IDS-C30 scores (p < 0.01). In summary, response rates were greater among patients with MDD randomized to EPA 4 g/d supplementation and in those who showed a greater ability to activate the synthesis of 18-HEPE. The inverse association of 18-HEPE with both systemic inflammation and symptoms of depression highlights the activation of the resolution of inflammation as a likely mechanism in the treatment of MDD with ω-3 fatty acid supplementation.

Excessive dietary linoleic acid promotes plasma accumulation of pronociceptive fatty acyl lipid mediators

Various fatty acyl lipid mediators are derived from dietary polyunsaturated fatty acids (PUFAs) and modulate nociception. The modern diet is rich in linoleic acid, which is associated with nociceptive hypersensitivities and may present a risk factor for developing pain conditions. Although recommendations about fatty acid intake exist for some diseases (e.g. cardiovascular disease), the role of dietary fatty acids in promoting pain disorders is not completely understood. To determine how dietary linoleic acid content influences the accumulation of pro- and anti-nociceptive fatty acyl lipid mediators, we created novel rodent diets using custom triglyceride blends rich in either linoleic acid or oleic acid. We quantified the fatty acyl lipidome in plasma of male and female rats fed these custom diets from the time of weaning through nine weeks of age. Dietary fatty acid composition determined circulating plasma fatty acyl lipidome content. Exposure to a diet rich in linoleic acid was associated with accumulation of linoleic and arachidonic acid-derived pro-nociceptive lipid mediators and reduction of anti-nociceptive lipid mediators derived from the omega-3 PUFAs. Our findings provide mechanistic insights into exaggerated nociceptive hypersensitivity associated with excessive dietary linoleic acid intake and highlight potential biomarkers for pain risk stratification.

Identification of a feed-forward loop between 15(S)-HETE and PGE2 in human amnion at parturition

Human parturition is associated with massive arachidonic acid (AA) mobilization in the amnion, indicating that large amounts of AA-derived eicosanoids are required for parturition. Prostaglandin E2 (PGE2) synthesized from the cyclooxygenase (COX) pathway is the best characterized AA-derived eicosanoid in the amnion which plays a pivotal role in parturition. The existence of any other pivotal AA-derived eicosanoids involved in parturition remains elusive. Here, we screened such eicosanoids in human amnion tissue with AA-targeted metabolomics and studied their role and synthesis in parturition by using human amnion fibroblasts and a mouse model. We found that lipoxygenase (ALOX) pathway-derived 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE) and its synthetic enzymes ALOX15 and ALOX15B were significantly increased in human amnion at parturition. Although 15(S)-HETE is ineffective on its own, it potently potentiated the activation of NF-κB by inflammatory mediators including lipopolysaccharide, interleukin-1β, and serum amyloid A1, resulting in the amplification of COX-2 expression and PGE2 production in amnion fibroblasts. In turn, we determined that PGE2 induced ALOX15/15B expression and 15(S)-HETE production through its EP2 receptor-coupled PKA pathway, thereby forming a feed-forward loop between 15(S)-HETE and PGE2 production in the amnion at parturition. Our studies in pregnant mice showed that 15(S)-HETE injection induced preterm birth with increased COX-2 and PGE2 abundance in the fetal membranes and placenta. Conclusively, 15(S)-HETE is identified as another crucial parturition-pertinent AA-derived eicosanoid in the amnion, which may form a feed-forward loop with PGE2 in parturition. Interruption of this feed-forward loop may be of therapeutic value for the treatment of preterm birth.

Enriched Marine Oil Supplement Increases Specific Plasma Specialized Pro-Resolving Mediators in Adults with Obesity

BACKGROUND

Specialized pro-resolving mediators (SPMs), synthesized from PUFAs, resolve inflammation and return damaged tissue to homeostasis. Thus, increasing metabolites of the SPM biosynthetic pathway may have potential health benefits for select clinical populations, such as subjects with obesity who display dysregulation of SPM metabolism. However, the concentrations of SPMs and their metabolic intermediates in humans with obesity remains unclear.

OBJECTIVES

The primary objective of this study was to determine if a marine oil supplement increased specific metabolites of the SPM biosynthetic pathway in adults with obesity. The second objective was to determine if the supplement changed the relative abundance of key immune cell populations. Finally, given the critical role of antibodies in inflammation, we determined if ex vivo CD19 + B-cell antibody production was modified by marine oil intervention.

METHODS

Twenty-three subjects [median age: 56 y; BMI (in kg/m2): 33.1] consumed 2 g/d of a marine oil supplement for 28-30 d. The supplement was particularly enriched with 18-hydroxyeicosapentaenoic (HEPE), 14-hydroxydocosahexaenoic acid (14-HDHA), and 17-HDHA. Blood was collected pre- and postsupplementation for plasma mass spectrometry oxylipin and fatty acid analyses, flow cytometry, and B-cell isolation. Paired t-tests and Wilcoxon tests were used for statistical analyses.

RESULTS

Relative to preintervention, the supplement increased 6 different HEPEs and HDHAs accompanied by changes in plasma PUFAs. Resolvin E1 and docosapentaenoic acid-derived maresin 1 concentrations were increased 3.5- and 4.7-fold upon intervention, respectively. The supplement did not increase the concentration of D-series resolvins and had no effect on the abundance of immune cells. Ex vivo B-cell IgG but not IgM concentrations were lowered postsupplementation.

CONCLUSIONS

A marine oil supplement increased select SPMs and their metabolic intermediates in adults with obesity. Additional studies are needed to determine if increased concentrations of specific SPMs control the resolution of inflammation in humans with obesity. This trial was registered at clinicaltrials.gov as NCT04701138.

LSEA Evaluation of Lipid Mediators of Inflammation in Lung and Cortex of Mice Exposed to Diesel Air Pollution

Airborne ultrafine particle (UFP) exposure is a great concern as they have been correlated to increased cardiovascular mortality, neurodegenerative diseases and morbidity in occupational and environmental settings. The ultrafine components of diesel exhaust particles (DEPs) represent about 25% of the emission mass; these particles have a great surface area and consequently high capacity to adsorb toxic molecules, then transported throughout the body. Previous in-vivo studies indicated that DEP exposure increases pro- and antioxidant protein levels and activates inflammatory response both in respiratory and cardiovascular systems. In cells, DEPs can cause additional reactive oxygen species (ROS) production, which attacks surrounding molecules, such as lipids. The cell membrane provides lipid mediators (LMs) that modulate cell-cell communication, inflammation, and resolution processes, suggesting the importance of understanding lipid modifications induced by DEPs. In this study, with a lipidomic approach, we evaluated in the mouse lung and cortex how DEP acute and subacute treatments impact polyunsaturated fatty acid-derived LMs. To analyze the data, we designed an ad hoc bioinformatic pipeline to evaluate the functional enrichment of lipid sets belonging to the specific biological processes (Lipid Set Enrichment Analysis-LSEA). Moreover, the data obtained correlate tissue LMs and proteins associated with inflammatory process (COX-2, MPO), oxidative stress (HO-1, iNOS, and Hsp70), involved in the activation of many xenobiotics as well as PAH metabolism (Cyp1B1), suggesting a crucial role of lipids in the process of DEP-induced tissue damage.

Gestational exposure to titanium dioxide, diesel exhaust, and concentrated urban air particles affects levels of specialized pro-resolving mediators in response to allergen in asthma-susceptible neonate lungs

Maternal gestational exposures to traffic and urban air pollutant particulates have been linked to increased risk and/or worsening asthma in children; however, mechanisms underlying this vertical transmission are not entirely understood. It was postulated that gestational particle exposure might affect the ability to elicit specialized proresolving mediator (SPM) responses upon allergen encounter in neonates. Lipidomic profiling of 50 SPMs was performed in lungs of neonates born to mice exposed to concentrated urban air particles (CAP), diesel exhaust particles (DEP), or less immunotoxic titanium dioxide particles (TiO2). While asthma-like phenotypes were induced with identical eosinophilia intensity across neonates of all particle-exposed mothers, levels of LXA4, HEPE and HETE isoforms, and HDoHe were only decreased by CAP and DEP only but not by TiO2. However, RvE2 and RvD1 were inhibited by all particles. In contrast, isomers of Maresin1 and Protectin D1 were variably elevated by CAP and DEP, whereas Protectin DX, PGE2, and TxB2 were increased in all groups. Only Protectin D1/DX, MaR1(n-3,DPA), 5(S),15(S)-DiHETE, PGE2, and RvE3 correlated with eosinophilia but the majority of other analytes, elevated or inhibited, showed no marked correlation with inflammation intensity. Evidence indicates that gestational particle exposure leads to both particle-specific and nonspecific effects on the SPM network.

Prostaglandins in biofluids in pregnancy and labour: A systematic review

Prostaglandins are thought to be important mediators in the initiation of human labour, however the evidence supporting this is not entirely clear. Determining how, and which, prostaglandins change during pregnancy and labour may provide insight into mechanisms governing labour initiation and the potential to predict timing of labour onset. The current study systematically searched the existing scientific literature to determine how biofluid levels of prostaglandins change throughout pregnancy before and during labour, and whether prostaglandins and/or their metabolites may be useful for prediction of labour. The databases EMBASE and MEDLINE were searched for English-language articles on prostaglandins measured in plasma, serum, amniotic fluid, or urine during pregnancy and/or spontaneous labour. Studies were assessed for quality and risk of bias and a qualitative summary of included studies was generated. Our review identified 83 studies published between 1968-2021 that met the inclusion criteria. As measured in amniotic fluid, levels of PGE2, along with PGF2α and its metabolite 13,14-dihydro-15-keto-PGF2α were reported higher in labour compared to non-labour. In blood, only 13,14-dihydro-15-keto-PGF2α was reported higher in labour. Additionally, PGF2α, PGF1α, and PGE2 were reported to increase in amniotic fluid as pregnancy progressed, though this pattern was not consistent in plasma. Overall, the evidence supporting changes in prostaglandin levels in these biofluids remains unclear. An important limitation is the lack of data on the complexity of the prostaglandin pathway outside of the PGE and PGF families. Future studies using new methodologies capable of co-assessing multiple prostaglandins and metabolites, in large, well-defined populations, will help provide more insight as to the identification of exactly which prostaglandins and/or metabolites consistently change with labour. Revisiting and revising our understanding of the prostaglandins may provide better targets for clinical monitoring of pregnancies. This study was supported by the Canadian Institutes of Health Research.

Local shifts in inflammatory and resolving lipid mediators in response to tendon overuse

Tendon inflammation has been implicated in both adaptive connective tissue remodeling and overuse-induced tendinopathy. Lipid mediators control both the initiation and resolution of inflammation, but their roles within tendon are largely unknown. Here, we profiled local shifts in intratendinous lipid mediators via liquid chromatography-tandem mass spectrometry in response to synergist ablation-induced plantaris tendon overuse. Sixty-four individual lipid mediators were detected in homogenates of plantaris tendons from ambulatory control rats. This included many bioactive metabolites of the cyclooxygenase (COX), lipoxygenase (LOX), and epoxygenase (CYP) pathways. Synergist ablation induced a robust inflammatory response at day 3 post-surgery characterized by epitenon infiltration of polymorphonuclear leukocytes and monocytes/macrophages (MΦ), heightened expression of inflammation-related genes, and increased intratendinous concentrations of the pro-inflammatory eicosanoids thromboxane B₂ and prostaglandin E₂ . By day 7, MΦ became the predominant myeloid cell type in tendon and there were further delayed increases in other COX metabolites including prostaglandins D₂ , F_2α , and I₂ . Specialized pro-resolving mediators including protectin D1, resolvin D2 and D6, as well as related pathway markers of D-resolvins (17-hydroxy-docosahexaenoic acid), E-resolvins (18-hydroxy-eicosapentaenoic acid), and lipoxins (15-hydroxy-eicosatetraenoic acid) were also increased locally in response to tendon overuse, as were anti-inflammatory fatty acid epoxides of the CYP pathway (eg, epoxy-eicosatrienoic acids). Nevertheless, intratendinous prostaglandins remained markedly increased even following 28 days of tendon overuse together with a lingering MΦ presence. These data reveal a delayed and prolonged local inflammatory response to tendon overuse characterized by an overwhelming predominance of pro-inflammatory eicosanoids and a relative lack of specialized pro-resolving lipid mediators.

Linoleic Acid-Derived Oxylipins Differentiate Early Stage Alcoholic Hepatitis From Mild Alcohol-Associated Liver Injury

Alcohol-associated liver disease (ALD) is a spectrum of liver disorders ranging from steatosis to steatohepatitis, fibrosis, and cirrhosis. Alcohol-associated hepatitis (AH) is an acute and often severe form of ALD with substantial morbidity and mortality. The mechanisms and mediators of ALD progression and severity are not well understood, and effective therapeutic options are limited. Various bioactive lipid mediators have recently emerged as important factors in ALD pathogenesis. The current study aimed to examine alterations in linoleic acid (LA)-derived lipid metabolites in the plasma of individuals who are heavy drinkers and to evaluate associations between these molecules and markers of liver injury and systemic inflammation. Analysis of plasma LA-derived metabolites was performed on 66 individuals who were heavy drinkers and 29 socially drinking but otherwise healthy volunteers. Based on plasma alanine aminotransferase (ALT) levels, 15 patients had no liver injury (ALT ≤ 40 U/L), 33 patients had mild liver injury (ALT > 40 U/L), and 18 were diagnosed with moderate AH (mAH) (Model for End-Stage Liver Disease score <20). Lipoxygenase-derived LA metabolites (13-hydroxy-octadecadienoic acid [13-HODE] and 13-oxo-octadecadienoic acid) were markedly elevated only in patients with mAH. The cytochrome P450-derived LA epoxides 9,10-epoxy-octadecenoic acid (9,10-EpOME) and 12,13-EpOME were decreased in all patients regardless of the presence or absence of liver injury. LA-derived diols 9,10-dihydroxy-octadecenoic acid (9,10-DiHOME) and 12,13-DiHOME as well as the corresponding diol/epoxide ratio were elevated in the mAH group, specifically compared to patients with mild liver injury. We found that 13-HODE and 12,13-EpOME (elevated and decreased, respectively) in combination with elevated interleukin-1β as independent predictors can effectively predict altered liver function as defined by elevated bilirubin levels. Conclusion: Specific changes in LA metabolites in individuals who are heavy drinkers can distinguish individuals with mAH from those with mild ALD.

Up-regulation of cytosolic prostaglandin E synthase in fetal-membrane and amniotic prostaglandin E2 accumulation in labor

Prostaglandin E2 (PGE2) is known to have important roles in labor, but the detailed mechanism underlying the spontaneous human labor remains unknown. Here, we examined the involvement of prostaglandin biosynthetic enzymes and transporter in the accumulation of PGE2 in amniotic fluid in human labor. PGE2 and its metabolites were abundant in amniotic fluid in deliveries at term in labor (TLB), but not at term not in labor (TNL). In fetal-membrane Transwell assays, levels of PGE2 production in both maternal and fetal compartments were significantly higher in the TLB group than the TNL group. In fetal-membrane, the mRNA level of PTGES3, which encodes cytosolic prostaglandin E synthase (cPGES), was significantly higher in TLB than in TNL, but the mRNA levels of the other PGE2-synthase genes were not affected by labor. Moreover, the mRNA level of PTGS2, which encodes cyclooxygenase-2 (COX-2) in the amnion was significantly higher in TLB than in TNL. Western blot analyses revealed that the levels of COX-1 and COX-2 were comparable between the two groups, however, the level of cPGES was relatively higher in TLB than in TNL. COXs, cPGES, and prostaglandin transporter (SLCO2A1) proteins were all expressed in both chorionic trophoblasts and amniotic epithelium. These findings suggest that COXs, cPGES and SLCO2A1 contribute to PGE2 production from fetal-membrane in labor.

Activation of Transient Receptor Potential Vanilloid 1 Channels in the Nucleus of the Solitary Tract and Activation of Dynorphin Input to the Median Preoptic Nucleus Contribute to Impaired BAT Thermogenesis in Diet-Induced Obesity

The impairment of cold-evoked activation of brown adipose tissue (BAT) in rats fed a high-fat diet (HFD) requires the activity of a vagal afferent to the medial nucleus of the solitary tract (mNTS). We determined the role of transient receptor potential vanilloid 1 (TRPV1) activation in the mNTS, and of a dynorphin input to the median preoptic nucleus (MnPO) in the impaired BAT thermogenic response to cold in HFD-fed rats. The levels of some linoleic acid (LA) metabolites, which can act as endogenous TRPV1 agonists, were elevated in the NTS of HFD rats compared with chow-fed rats. In HFD rats, nanoinjections of the TRPV1 antagonist, capsazepine (CPZ) in the NTS rescued the impaired BAT sympathetic nerve activity (BAT SNA) and thermogenic responses to cold. In contrast, in chow-fed rats, cold-evoked BAT SNA and BAT thermogenesis were not changed by nanoinjections of CPZ into the NTS. Axon terminals of NTS neurons that project to the dorsal lateral parabrachial nucleus (LPBd) were closely apposed to LPBd neurons that project to the MnPO. Many of the neurons in the LPBd that expressed c-fos during cold challenge were dynorphinergic. In HFD rats, nanoinjections of the κ opioid receptor (KOR) antagonist, nor-binaltorphimine (nor-BNI), in the MnPO rescued the impaired BAT SNA and thermogenic responses to cold. These data suggest that HFD increases the content of endogenous ligands of TRPV1 in the NTS, which increases the drive to LPBd neurons that in turn release dynorphin in the MnPO to impair activation of BAT.

Parenteral Fish-Oil Containing Lipid Emulsions Limit Initial Lipopolysaccharide-Induced Host Immune Responses in Preterm Pigs

Multicomponent lipid emulsions are available for critical care of preterm infants. We sought to determine the impact of different lipid emulsions on early priming of the host and its response to an acute stimulus. Pigs delivered 7d preterm (n = 59) were randomized to receive different lipid emulsions for 11 days: 100% soybean oil (SO), mixed oil emulsion (SO, medium chain olive oil and fish oil) including 15% fish oil (MO15), or 100% fish oil (FO100). On day 11, pigs received an 8-h continuous intravenous infusion of either lipopolysaccharide (LPS—lyophilized Escherichia coli) or saline. Plasma was collected for fatty acid, oxylipin, metabolomic, and cytokine analyses. At day 11, plasma omega-3 fatty acid levels in the FO100 groups showed the highest increase in eicosapentaenoic acid, EPA (0.1 ± 0.0 to 9.7 ± 1.9, p < 0.001), docosahexaenoic acid, DHA (day 0 = 2.5 ± 0.7 to 13.6 ± 2.9, p < 0.001), EPA and DHA-derived oxylipins, and sphingomyelin metabolites. In the SO group, levels of cytokine IL1β increased at the first hour of LPS infusion (296.6 ± 308 pg/mL) but was undetectable in MO15, FO100, or in the animals receiving saline instead of LPS. Pigs in the SO group showed a significant increase in arachidonic acid (AA)-derived prostaglandins and thromboxanes in the first hour (p < 0.05). No significant changes in oxylipins were observed with either fish-oil containing group during LPS infusion. Host priming with soybean oil in the early postnatal period preserves a higher AA:DHA ratio and the ability to acutely respond to an external stimulus. In contrast, fish-oil containing lipid emulsions increase DHA, exacerbate a deficit in AA, and limit the initial LPS-induced inflammatory responses in preterm pigs.

Dose- and time-dependent increase in circulating anti-inflammatory and pro-resolving lipid mediators following eicosapentaenoic acid supplementation in patients with major depressive disorder and chronic inflammation

BACKGROUND

Eicosapentaenoic acid (EPA) supplementation is an effective treatment option in major depressive disorder (MDD) associated with chronic low-grade inflammation. EPA is the precursor of specialized pro-resolving lipid mediators (SPMs) termed resolvins (Rv), that serve important roles in the resolution of inflammation. The objective of this study was to assess the effects of different doses of EPA on plasma concentrations of EPA metabolites and SPMs in MDD patients.

METHODS

In a 2-site study, 61 MDD patients with body mass index >25 kg/m² and serum high-sensitivity C-reactive protein ≥3 μg/mL were enrolled in a 12-week randomized trial comparing EPA 1, 2, and 4 g/d to placebo. Plasma EPA (mol%) and SPMs (pg/mL) were measured in 42 study completers at baseline and at the end of treatment by liquid chromatography/mass spectrometry.

RESULTS

Plasma EPA and SPM concentrations did not change in the placebo group during 12 weeks of treatment. Plasma EPA and EPA-derived metabolites increased significantly and dose-dependently in all EPA supplementation arms. The increase in 18-hydroxyeicosapentaenoic acid (18-HEPE), the precursor of RvE1-3, was significantly greater with the 4 g/d EPA dose than the other doses from week 4 to 12. RvE1 was undetected in all treatment groups, while RvE2 was detected in half of the subjects both at baseline and after treatment, with dose-dependent increases. RvE3 was detected only after supplementation, dose-dependently. A significant reduction in plasma arachidonic acid (AA), relative to baseline, was observed in all EPA arms. This was in contrast with an increase in AA-derived SPM lipoxin B4 (LXB4) in the 4 g/d arm.

CONCLUSIONS

Our results show a robust effect of EPA 4 g/d supplementation in increasing plasma EPA and 18-HEPE levels, associated with improved conversion to RvE2-3, and LXB4 levels.

The Role(s) of Eicosanoids and Exosomes in Human Parturition

The roles that eicosanoids play during pregnancy and parturition are crucial to a successful outcome. A better understanding of the regulation of eicosanoid production and the roles played by the various end products during pregnancy and parturition has led to our view that accurate measurements of a panel of those end products has exciting potential as diagnostics and prognostics of preterm labor and delivery. Exosomes and their contents represent an exciting new area for research of movement of key biological factors circulating between tissues and organs akin to a parallel endocrine system but involving key intracellular mediators. Eicosanoids and enzymes regulating their biosynthesis and metabolism as well as regulatory microRNAs have been identified within exosomes. In this review, the regulation of eicosanoid production, abundance and actions during pregnancy will be explored. Additionally, the functional significance of placental exosomes will be discussed.

Prostaglandin and prostamide concentrations in amniotic fluid of women with spontaneous labor at term with and without clinical chorioamnionitis

OBJECTIVE

Prostaglandins (PGs) are considered universal mediators for the process of physiological parturition. This is based on observations that amniotic fluid concentrations of PGs are elevated prior to and during the onset of labor (mostly utilizing immunoassays). Distinguishing PGs from similarly structured molecules (i.e. prostamides; PG-EA) is difficult given the cross-reactivity of available antibodies and the chemical similarity between these compounds. Herein, this limitation was overcome by utilizing mass spectrometry to determine PG and PG-EA concentrations in amniotic fluid of women with spontaneous labor at term and in those with clinical chorioamnionitis (CHAM), the most common infection-related diagnosis made in labor and delivery units worldwide.

STUDY DESIGN

Liquid chromatography-tandem mass spectrometry (LC MS/MS) was used to determine the PG and PG-EA content in amniotic fluid samples of women with spontaneous labor at term with (n = 14) or without (n = 28) CHAM. Controls included women who delivered at term without labor (n = 10).

RESULTS

PGE_2, PGF_2α, and 13,14-dihydro-15-keto-PGF_2α (PGFM) were higher in amniotic fluid of women with spontaneous labor at term than in those without labor. PGE₂, PGF_2α, and PGFM were also higher in amniotic fluid of women with CHAM than in those without labor. However, PGE₂-EA and PGF_2α-EA were lower in amniotic fluid of women with CHAM than in those without CHAM. The ratios of PGE₂ to PGE₂-EA and PGF_2α to PGF_2α-EA were higher in amniotic fluid of women with spontaneous labor at term with or without CHAM than in those without labor; yet, the ratio of PGF_2α to PGF_2α-EA was greater in women with CHAM than in those without this clinical condition.

CONCLUSIONS

Spontaneous labor at term with or without CHAM is characterized by elevated amniotic fluid concentrations of prostaglandins (PGE₂, PGF_2α, and PGFM) but not prostamides. Quantification of these products by LC MS/MSlc==may potentially be of utility in identifying their physiological functions relevant to parturition.

SUMMARY

Prostaglandins (PGs) are critical for the onset and progression of labor. Structural similarities of PGs and prostamides (PG-EA) prevents their specific identification by immunoassay. We utilized LC MS/MS to determine PG and PG-EA content in amniotic fluid (AF) of women with spontaneous labor at term with or without CHAM and women who delivered at term without labor. Higher aamniotic ffluid PG levels were observed in women with spontaneous labor with and without CHAM compared to women delivering without labor. PG-EA levels in amniotic fluid of women with spontaneous labor and CHAM were lower than in women with spontaneous labor without CHAM but not those without labor. Ratios of PGs to PG-EAs were higher in AF of women with labor and CHAM compared to those without labor. Delineation of these products by LC MS/MS may potentially be of utility in identifying their physiological functions relevant to parturition.

RNA Sequencing Reveals Diverse Functions of Amniotic Fluid Neutrophils and Monocytes/Macrophages in Intra-Amniotic Infection

Intra-amniotic infection, the invasion of microbes into the amniotic cavity resulting in inflammation, is a clinical condition that can lead to adverse pregnancy outcomes for the mother and fetus as well as severe long-term neonatal morbidities. Despite much research focused on the consequences of intra-amniotic infection, there remains little knowledge about the innate immune cells that respond to invading microbes. We performed RNA-seq of sorted amniotic fluid neutrophils and monocytes/macrophages from women with intra-amniotic infection to determine the transcriptomic differences between these innate immune cells. Further, we sought to identify specific transcriptomic pathways that were significantly altered by the maternal or fetal origin of amniotic fluid neutrophils and monocytes/macrophages, the presence of a severe fetal inflammatory response, and pregnancy outcome (i.e., preterm or term delivery). We show that significant transcriptomic differences exist between amniotic fluid neutrophils and monocytes/macrophages from women with intra-amniotic infection, indicating the distinct roles these cells play. The transcriptome of amniotic fluid immune cells varies based on their maternal or fetal origin, and the significant transcriptomic differences between fetal and maternal monocytes/macrophages imply that those of fetal origin exhibit impaired functions. Notably, transcriptomic changes in amniotic fluid monocytes/macrophages suggest that these immune cells collaborate with neutrophils in the trafficking of fetal leukocytes throughout the umbilical cord (i.e., funisitis). Finally, amniotic fluid neutrophils and monocytes/macrophages from preterm deliveries display enhanced transcriptional activity compared to those from term deliveries, highlighting the protective role of these cells during this vulnerable period. Collectively, these findings demonstrate the underlying complexity of local innate immune responses in women with intra-amniotic infection and provide new insights into the functions of neutrophils and monocytes/macrophages in the amniotic cavity.

Eicosanoid Inflammatory Mediators Are Robustly Associated With Blood Pressure in the General Population

Background Epidemiological and animal studies have associated systemic inflammation with blood pressure (BP). However, the mechanistic factors linking inflammation and BP remain unknown. Fatty acid-derived eicosanoids serve as mediators of inflammation and have been suggested to regulate renal vascular tone, peripheral resistance, renin-angiotensin system, and endothelial function. We hypothesize that specific proinflammatory and anti-inflammatory eicosanoids are linked with BP. Methods and Results We studied a population sample of 8099 FINRISK 2002 participants randomly drawn from the Finnish population register (53% women; mean age, 48±13 years) and, for external validation, a sample of 2859 FHS (Framingham Heart Study) Offspring study participants (55% women; mean age, 66±9 years). Using nontargeted liquid chromatography-mass spectrometry, we profiled 545 distinct high-quality eicosanoids and related oxylipin mediators in plasma. Adjusting for conventional hypertension risk factors, we observed 187 (34%) metabolites that were significantly associated with systolic BP (P<Bonferroni-corrected threshold of 0.05/545). We used forward selection linear regression modeling in FINRISK to define a general formula for individual eicosanoid risk score. Individuals of the top risk score quartile in FINRISK had a 9.0 (95% CI, 8.0-10.1) mm Hg higher systolic BP compared with individuals in the lowest quartile in fully adjusted models. Observed metabolite associations were consistent across FINRISK and FHS. Conclusions Plasma eicosanoids demonstrate strong associations with BP in the general population. As eicosanoid compounds affect numerous physiological processes that are central to BP regulation, they may offer new insights about the pathogenesis of hypertension, as well as serve as potential targets for therapeutic intervention.

Non-inflammatory Physiology of "Inflammatory" Mediators - Unalamation, a New Paradigm

Many small molecules (mostly lipids derived from polyunsaturated fatty acids) and proteins (e. g., cytokines and chemokines) are labeled as inflammatory mediators for their role in eliciting physiological responses to injury. While acute inflammatory events are controlled by anti-inflammatory drugs, lasting damage to the tissues as a result of persistent inflammation is increasingly viewed as the root cause of many chronic diseases that include cardiovascular, neurological, and metabolic disorders, rheumatoid arthritis, and cancer. Interestingly, some of the “inflammatory” mediators also participate in normal developmental physiology without eliciting inflammation. Anti-inflammatory drugs that target the biosynthesis of these mediators are too indiscriminate to distinguish their two divergent physiological roles. A more precise definition of these two physiological processes partaken by the “inflammatory” mediators is warranted to identify their differences. The new paradigm is named “unalamation” ('ə‘n'əlAmāSH(ə)n) to distinguish from inflammation and to identify appropriate intervention strategies to mitigate inflammation associated pathophysiology without affecting the normal developmental physiology.

Interleukin 6 reduces allopregnanolone synthesis in the brain and contributes to age-related cognitive decline in mice

Cognitive decline with age is a harmful process that can reduce quality of life. Multiple factors have been established to contribute to cognitive decline, but the overall etiology remains unknown. Here, we hypothesized that cognitive dysfunction is mediated, in part, by increased levels of inflammatory cytokines that alter allopregnanolone (AlloP) levels, an important neurosteroid in the brain. We assessed the levels and regulation of AlloP and the effects of AlloP supplementation on cognitive function in 4-month-old and 24-month-old male C57BL/6 mice. With age, the expression of enzymes involved in the AlloP synthetic pathway was decreased and corticosterone (CORT) synthesis increased. Supplementation of AlloP improved cognitive function. Interestingly, interleukin 6 (IL-6) infusion in young animals significantly reduced the production of AlloP compared with controls. It is notable that inhibition of IL-6 with its natural inhibitor, soluble membrane glycoprotein 130, significantly improved spatial memory in aged mice. These findings were supported by in vitro experiments in primary murine astrocyte cultures, indicating that IL-6 decreases production of AlloP and increases CORT levels. Our results indicate that age-related increases in IL-6 levels reduce progesterone substrate availability, resulting in a decline in AlloP levels and an increase in CORT. Furthermore, our results indicate that AlloP is a critical link between inflammatory cytokines and the age-related decline in cognitive function.

Intra-amniotic inflammation induces preterm birth by activating the NLRP3 inflammasome†

Intra-amniotic inflammation is strongly associated with spontaneous preterm labor and birth, the leading cause of perinatal mortality and morbidity worldwide. Previous studies have suggested a role for the NLRP3 (NLR family pyrin domain-containing protein 3) inflammasome in the mechanisms that lead to preterm labor and birth. However, a causal link between the NLRP3 inflammasome and preterm labor/birth induced by intra-amniotic inflammation has not been established. Herein, using an animal model of lipopolysaccharide-induced intra-amniotic inflammation (IAI), we demonstrated that there was priming of the NLRP3 inflammasome (1) at the transcriptional level, indicated by enhanced mRNA expression of inflammasome-related genes (Nlrp3, Casp1, Il1b); and (2) at the protein level, indicated by greater protein concentrations of NLRP3, in both the fetal membranes and decidua basalis prior to preterm birth. Additionally, we showed that there was canonical activation of the NLRP3 inflammasome in the fetal membranes, but not in the decidua basalis, prior to IAI-induced preterm birth as evidenced by increased protein levels of active caspase-1. Protein concentrations of released IL1β were also increased in both the fetal membranes and decidua basalis, as well as in the amniotic fluid, prior to IAI-induced preterm birth. Finally, using the specific NLRP3 inhibitor, MCC950, we showed that in vivo inhibition of the NLRP3 inflammasome reduced IAI-induced preterm birth and neonatal mortality. Collectively, these results provide a causal link between NLRP3 inflammasome activation and spontaneous preterm labor and birth in the context of intra-amniotic inflammation. We also showed that, by targeting the NLRP3 inflammasome, adverse pregnancy and neonatal outcomes can be significantly reduced.

Distinct contributions of two choline-producing enzymatic activities to lysophosphatidic acid production in human amniotic fluid from pregnant women in the second trimester and after parturition

The purpose of this study was to clarify whether human amniotic fluid (AF) contains a significant level of bioactive lysophosphatidic acid (LPA) and, whether autotaxin (ATX) is involved in the production of LPA, if present. Using LC-MS/MS, we found a higher ratio of levels of LPA and its precursor lysophosphatidylcholine (LPC) in AF collected after parturition than that in AF collected at the middle stage of pregnancy. We detected significant choline-producing enzymatic activity toward an exogenous LPC in AF at the middle stage of pregnancy, about half of which was ascribable to ATX. In AF collected after parturition, the ATX-independent choline-producing activity of glycerophosphcholine phosphodiesterase coupled to lysophospholipase A activity was increased in relative to the lysophospholipase D activity of ATX. These results suggest that the increased LPA/LPC ratio in AF at the term of pregnancy was due to not only a moderate increase in the level of LPC, but also an unknown mechanism involving epithelial cells bathed with AF.

Intramuscular inflammatory and resolving lipid profile responses to an acute bout of resistance exercise in men

Lipid mediators including classical arachidonic acid‐derived eicosanoids (e.g. prostaglandins and leukotrienes) and more recently identified specialized pro‐resolving‐mediator metabolites of the omega‐3 fatty acids play essential roles in initiation, self‐limitation, and active resolution of acute inflammatory responses. In this study, we examined the bioactive lipid mediator profile of human skeletal muscle at rest and following acute resistance exercise. Twelve male subjects completed a single bout of maximal isokinetic unilateral knee extension exercise and muscle biopsies were taken from the m.vastus lateralis before and at 2, 4, and 24 h of recovery. Muscle tissue lipid mediator profile was analyzed via liquid chromatography–mass spectrometry (LC‐MS)‐based targeted lipidomics. At 2 h postexercise, there was an increased intramuscular abundance of cyclooxygenase (COX)‐derived thromboxanes (TXB₂: 3.33 fold) and prostaglandins (PGE₂: 2.52 fold and PGF_2α: 1.77 fold). Resistance exercise also transiently increased muscle concentrations of lipoxygenase (LOX) pathway‐derived leukotrienes (12‐Oxo LTB₄: 1.49 fold and 20‐COOH LTB₄: 2.91 fold), monohydroxy‐eicosatetraenoic acids (5‐HETE: 2.66 fold, 12‐HETE: 2.83 fold, and 15‐HETE: 1.69 fold) and monohydroxy‐docosahexaenoic acids (4‐HDoHE: 1.69 fold, 7‐HDoHE: 1.58 fold and 14‐HDoHE: 2.35 fold). Furthermore, the abundance of CYP pathway‐derived epoxy‐ and dihydroxy‐eicosatrienoic acids was increased in 2 h postexercise biopsies (5,6‐EpETrE: 2.48 fold, 11,12‐DiHETrE: 1.66 fold and 14,15‐DiHETrE: 2.23 fold). These data reveal a range of bioactive lipid mediators as present within human skeletal muscle tissue and demonstrate that acute resistance exercise transiently stimulates the local production of both proinflammatory eicosanoids and pathway markers in specialized proresolving mediator biosynthesis circuits.

Disorders of placental villous maturation in fetal death

Objective The aims of this study were to ascertain the frequency of disorders of villous maturation in fetal death and to also delineate other placental histopathologic lesions in fetal death. Methods This was a retrospective observational cohort study of fetal deaths occurring among women between January 2004 and January 2016 at Hutzel Women's Hospital, Detroit, MI, USA. Cases comprised fetuses with death beyond 20 weeks' gestation. Fetal deaths with congenital anomalies and multiple gestations were excluded. Controls included pregnant women without medical/obstetrical complications and delivered singleton, term (37-42 weeks) neonate with 5-min Apgar score ≥7 and birthweight between the 10th and 90th percentiles. Results Ninety-two percent (132/143) of placentas with fetal death showed placental histologic lesions. Fetal deaths were associated with (1) higher frequency of disorders of villous maturation [44.0% (64/143) vs. 1.0% (4/405), P < 0.0001, prevalence ratio, 44.6; delayed villous maturation, 22% (31/143); accelerated villous maturation, 20% (28/143); and maturation arrest, 4% (5/143)]; (2) higher frequency of maternal vascular malperfusion lesions [75.5% (108/143) vs. 35.7% (337/944), P < 0.0001, prevalence ratio, 2.1] and fetal vascular malperfusion lesions [88.1% (126/143) vs. 19.7% (186/944), P < 0.0001, prevalence ratio, 4.5]; (3) higher frequency of placental histologic patterns suggestive of hypoxia [59.0% (85/143) vs. 9.3% (82/942), P < 0.0001, prevalence ratio, 6.8]; and (4) higher frequency of chronic inflammatory lesions [53.1% (76/143) vs. 29.9% (282/944), P < 0.001, prevalence ratio 1.8]. Conclusion This study demonstrates that placentas of women with fetal death were 44 times more likely to present disorders of villous maturation compared to placentas of those with normal pregnancy. This suggests that the burden of placental disorders of villous maturation lesions is substantial.

IRE1α-XBP1 signaling in leukocytes controls prostaglandin biosynthesis and pain

Inositol-requiring enzyme 1[α] (IRE1[α])-X-box binding protein spliced (XBP1) signaling maintains endoplasmic reticulum (ER) homeostasis while controlling immunometabolic processes. Yet, the physiological consequences of IRE1α-XBP1 activation in leukocytes remain unexplored. We found that induction of prostaglandin-endoperoxide synthase 2 (Ptgs2/Cox-2) and prostaglandin E synthase (Ptges/mPGES-1) was compromised in IRE1α-deficient myeloid cells undergoing ER stress or stimulated through pattern recognition receptors. Inducible biosynthesis of prostaglandins, including the pro-algesic mediator prostaglandin E2 (PGE₂), was decreased in myeloid cells that lack IRE1α or XBP1 but not other ER stress sensors. Functional XBP1 transactivated the human PTGS2 and PTGES genes to enable optimal PGE₂ production. Mice that lack IRE1α-XBP1 in leukocytes, or that were treated with IRE1α inhibitors, demonstrated reduced pain behaviors in PGE₂-dependent models of pain. Thus, IRE1α-XBP1 is a mediator of prostaglandin biosynthesis and a potential target to control pain.

Altered productions of prostaglandins and prostamides by human amnion in response to infectious and inflammatory stimuli identified by mutliplex mass spectrometry

INTRODUCTION

Prostaglandins are critical for the onset and progression of labor in mammals, and are formed by the metabolism of arachidonic acid. The products of arachidonic acid, 2-arachidonoylglycerol (2-AG), and anandamide (AEA) have a similar lipid back bone but differing polar head groups, meaning that identification of these products by immunoassay can be difficult.

MATERIALS AND METHODS

In the current study, we present the use of mass spectrometry as multiplex method of identifying the specific end products of arachidonic and anandamide metabolism by human derived amnion explants treated with either an infectious agent (LPS) or inflammatory mediator (IL-1β or TNF-α).

RESULTS

Human amnion tissue explants treated with LPS, IL-1β, or TNF-α increased production of prostaglandin E₂ (PGE₂; p < 0.05) but decreased PGFM. Overall, PGE₂ production was greater compared to the other prostaglandins and prostamides irrespective of treatment.

CONCLUSIONS

The findings of the current study are in keeping with the literature which describes amnion tissues as predominantly producing PGE₂. The use of mass spectrometry for the differential identification of prostaglandins, prostamides, and other eicosanoids may help better elucidate mechanisms of preterm labor, and lead to new targets for the prediction of risk for preterm labor and/or birth.

Preterm labor is characterized by a high abundance of amniotic fluid prostaglandins in patients with intra-amniotic infection or sterile intra-amniotic inflammation

Objective: To distinguish between prostaglandin and prostamide concentrations in the amniotic fluid of women who had an episode of preterm labor with intact membranes through the utilisation of liquid chromatography-tandem mass spectrometry.Study design: Liquid chromatography-tandem mass spectrometry analysis of amniotic fluid of women with preterm labor and (1) subsequent delivery at term (2) preterm delivery without intra-amniotic inflammation; (3) preterm delivery with sterile intra-amniotic inflammation (interleukin (IL)-6>2.6 ng/mL without detectable microorganisms); and (4) preterm delivery with intra-amniotic infection [IL-6>2.6 ng/mL with detectable microorganisms].Results: (1) amniotic fluid concentrations of PGE₂, PGF_2α, and PGFM were higher in patients with intra-amniotic infection than in those without intra-amniotic inflammation; (2) PGE₂ and PGF_2α concentrations were also greater in patients with intra-amniotic infection than in those with sterile intra-amniotic inflammation; (3) patients with sterile intra-amniotic inflammation had higher amniotic fluid concentrations of PGE₂ and PGFM than those without intra-amniotic inflammation who delivered at term; (4) PGFM concentrations were also greater in women with sterile intra-amniotic inflammation than in those without intra-amniotic inflammation who delivered preterm; (5) amniotic fluid concentrations of prostamides (PGE₂-EA and PGF_2α-EA) were not different among patients with preterm labor; (6) amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in cases with intra-amniotic inflammation; and (7) the PGE₂:PGE₂-EA and PGF_2α:PGF_2α-EA ratios were higher in patients with intra-amniotic infection compared to those without inflammation.Conclusions: Mass spectrometric analysis of amniotic fluid indicated that amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in women with preterm labor and intra-amniotic infection than in other patients with an episode of preterm labor. Yet, women with intra-amniotic infection had greater amniotic fluid concentrations of PGE₂ and PGF_2α than those with sterile intra-amniotic inflammation, suggesting that these two clinical conditions may be differentiated by using mass spectrometric analysis of amniotic fluid.

The origin of amniotic fluid monocytes/macrophages in women with intra-amniotic inflammation or infection

Background Monocytes, after neutrophils, are the most abundant white blood cells found in the amniotic cavity of women with intra-amniotic inflammation/infection. However, the origin of such cells has not been fully investigated. Herein, we determined (1) the origin of amniotic fluid monocytes/macrophages from women with intra-amniotic inflammation/infection, (2) the relationship between the origin of amniotic fluid monocytes/macrophages and preterm or term delivery and (3) the localization of monocytes/macrophages in the placental tissues. Methods Amniotic fluid samples (n = 16) were collected from women with suspected intra-amniotic inflammation or infection. Amniotic fluid monocytes/macrophages were purified by fluorescence-activated cell sorting, and DNA fingerprinting was performed. Blinded placental histopathological evaluations were conducted. Immunohistochemistry was performed to detect CD14+ monocytes/macrophages in the placental tissues. Results DNA fingerprinting revealed that (1) 56.25% (9/16) of amniotic fluid samples had mostly fetal monocytes/macrophages, (2) 37.5% (6/16) had predominantly maternal monocytes/macrophages and (3) one sample (6.25% [1/16]) had a mixture of fetal and maternal monocytes/macrophages. (4) Most samples with predominantly fetal monocytes/macrophages were from women who delivered early preterm neonates (77.8% [7/9]), whereas all samples with mostly maternal monocytes/macrophages or a mixture of both were from women who delivered term or late preterm neonates (100% [7/7]). (5) Most of the women included in this study presented acute maternal and fetal inflammatory responses in the placenta (85.7% [12/14]). (6) Women who had mostly fetal monocytes/macrophages in amniotic fluid had abundant CD14+ cells in the umbilical cord and chorionic plate, whereas women with mostly maternal amniotic fluid monocytes/macrophages had abundant CD14+ cells in the chorioamniotic membranes. Conclusion Amniotic fluid monocytes/macrophages can be of either fetal or maternal origin, or a mixture of both, in women with intra-amniotic inflammation or infection. These immune cells could be derived from the fetal and maternal vasculature of the placenta.

Ethanol and unsaturated dietary fat induce unique patterns of hepatic ω-6 and ω-3 PUFA oxylipins in a mouse model of alcoholic liver disease

Alcoholic liver disease (ALD), a significant health problem, progresses through the course of several pathologies including steatosis, steatohepatitis, fibrosis, and cirrhosis. There are no effective FDA-approved medications to prevent or treat any stages of ALD, and the mechanisms involved in ALD pathogenesis are not well understood. Bioactive lipid metabolites play a crucial role in numerous pathological conditions, as well as in the induction and resolution of inflammation. Herein, a hepatic lipidomic analysis was performed on a mouse model of ALD with the objective of identifying novel metabolic pathways and lipid mediators associated with alcoholic steatohepatitis, which might be potential novel biomarkers and therapeutic targets for the disease. We found that ethanol and dietary unsaturated, but not saturated, fat caused elevated plasma ALT levels, hepatic steatosis and inflammation. These pathologies were associated with increased levels of bioactive lipid metabolites generally involved in pro-inflammatory responses, including 13-hydroxy-octadecadienoic acid, 9,10- and 12,13-dihydroxy-octadecenoic acids, 5-, 8-, 9-, 11-, 15-hydroxy-eicosatetraenoic acids, and 8,9- and 11,12-dihydroxy-eicosatrienoic acids, in parallel with an increase in pro-resolving mediators, such as lipoxin A4, 18-hydroxy-eicosapentaenoic acid, and 10S,17S-dihydroxy-docosahexaenoic acid. Elucidation of alterations in these lipid metabolites may shed new light into the molecular mechanisms underlying ALD development/progression, and be potential novel therapeutic targets.

Human β-defensin-1: A natural antimicrobial peptide present in amniotic fluid that is increased in spontaneous preterm labor with intra-amniotic infection

PROBLEM

Human β-defensins (HBDs) are antimicrobial peptides that participate in the soluble innate immune mechanisms against infection. Herein, we determined whether HBD-1 was present in amniotic fluid during normal pregnancy and whether its concentrations change with intra-amniotic inflammation and/or infection.

METHOD OF STUDY

Amniotic fluid was collected from 219 women in the following groups: (a) midtrimester who delivered at term (n = 35); (b) term with (n = 33) or without (n = 17) labor; (c) preterm labor with intact membranes who delivered at term (n = 29) or who delivered preterm with (n = 19) and without (n = 29) intra-amniotic inflammation and infection or with intra-amniotic inflammation but without infection (n = 21); and (d) preterm prelabor rupture of membranes (pPROM) with (n = 19) and without (n = 17) intra-amniotic inflammation/infection. Amniotic fluid HBD-1 concentrations were determined using a sensitive and specific ELISA kit.

RESULTS

(a) HBD-1 was detectable in all amniotic fluid samples; (b) amniotic fluid concentrations of HBD-1 were changed with gestational age (midtrimester vs term no labor), being higher in midtrimester; (c) amniotic fluid concentrations of HBD-1 were similar between women with and without spontaneous labor at term; (d) among patients with spontaneous preterm labor, amniotic fluid concentrations of HBD-1 in women with intra-amniotic inflammation/infection and in those with intra-amniotic inflammation without infection were greater than in women without intra-amniotic inflammation or infection who delivered preterm or at term; and (e) the presence of intra-amniotic inflammation and infection in patients with pPROM did not change amniotic fluid concentrations of HBD-1.

CONCLUSION

HBD-1 is a physiological constituent of amniotic fluid that is increased in midtrimester during normal pregnancy and in the presence of culturable microorganisms in the amniotic cavity. These findings provide insight into the soluble host defense mechanisms against intra-amniotic infection.

Metabolomics of the amniotic fluid: Is it a feasible approach to evaluate the safety of Chinese medicine during pregnancy?

The use of Chinese medicines (CMs) during pregnancy has long been a major public health concern. Although CMs have been shown to be effective in treating infertility and preventing miscarriage, their use has been restricted, mainly because of limited knowledge of their potential toxicity. Accurate toxicology data are urgently required to assess whether these CMs are safe for maternal health and fetal development. Amniotic fluid (AF) contains carbohydrates, lipids and phospholipids, urea and proteins, all of which aid in the growth of the fetus and reflect the mother's health status as well. The changes in metabolomic patterns of AF are related to pathophysiological occurrences during the course of pregnancy. In this review, we provide a summary of the research performed in recent years on metabolomic AF samples, and use our previous study as an example to explore the feasibility of metabolomics of AF to evaluate the safety of CMs during pregnancy. We believe that metabolomics of AF play a far more important role than traditional morphology methods in the safety evaluation of CMs for pregnancy, with a higher sensitivity and correlation.

Inflammation-Induced Adverse Pregnancy and Neonatal Outcomes Can Be Improved by the Immunomodulatory Peptide Exendin-4

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide. Inflammation is causally linked to preterm birth; therefore, finding an intervention that dampens maternal and fetal inflammatory responses may provide a new strategy to prevent adverse pregnancy and neonatal outcomes. Using animal models of systemic maternal inflammation [intraperitoneal injection of lipopolysaccharide (LPS)] and fetal inflammation (intra-amniotic administration of LPS), we found that (1) systemic inflammation induced adverse pregnancy and neonatal outcomes by causing a severe maternal cytokine storm and a mild fetal cytokine response; (2) fetal inflammation induced adverse pregnancy and neonatal outcomes by causing a mild maternal cytokine response and a severe fetal cytokine storm; (3) exendin-4 (Ex4) treatment of dams with systemic inflammation or fetal inflammation improved adverse pregnancy outcomes by modestly reducing the rate of preterm birth; (4) Ex4 treatment of dams with systemic, but not local, inflammation considerably improved neonatal outcomes, and such neonates continued to thrive; (5) systemic inflammation facilitated the diffusion of Ex4 through the uterus and the maternal-fetal interface; (6) neonates born to Ex4-treated dams with systemic inflammation displayed a similar cytokine profile to healthy control neonates; and (7) treatment with Ex4 had immunomodulatory effects by inducing an M2 macrophage polarization and increasing anti-inflammatory neutrophils, as well as suppressing the expansion of CD8+ regulatory T cells, in neonates born to dams with systemic inflammation. Collectively, these results provide evidence that dampening maternal systemic inflammation through novel interventions, such as Ex4, can improve the quality of life for neonates born to women with this clinical condition.

Anti-inflammatory role of 15-lipoxygenase contributes to the maintenance of skin integrity in mice

15-lipoxygenase is involved in the generation of specialized pro-resolving lipid mediators that play essential roles in resolution and inflammatory responses. Here, we investigated anti-inflammatory role of Alox15 in skin homeostasis. We demonstrated that knockout (KO) of Alox15 led to hair loss and disrupted the structural integrity of the dorsal skin. Alox15 KO resulted in loss of hair follicle stem cells and abnormal transition of dermal adipocytes into fibroblasts. Alox15 deficiency increased infiltration of proinflammatory macrophages and upregulated proinflammatory and necroptotic signaling in dermal adipose tissue in the dorsal skin. Lipidomic analysis revealed severe loss of resolvin D2 in the dorsal skin of Alox15 KO mice compared to wild type controls. Treatment with resolvin D2 reduced skin inflammation in Alox15 KO mice. Collectively, these results indicate that Alox15-mediated production of resolvin D2 is required to maintain skin integrity by suppressing dermal inflammation.

The immunophenotype of amniotic fluid leukocytes in normal and complicated pregnancies

PROBLEM

The immune cellular composition of amniotic fluid is poorly understood. Herein, we determined: 1) the immunophenotype of amniotic fluid immune cells during the second and third trimester in the absence of intra-amniotic infection/inflammation; 2) whether amniotic fluid T cells and ILCs display different phenotypical characteristics to that of peripheral cells; and 3) whether the amniotic fluid immune cells are altered in women with intra-amniotic infection/inflammation.

METHOD OF STUDY

Amniotic fluid samples (n = 57) were collected from 15 to 40 weeks of gestation in women without intra-amniotic infection/inflammation. Samples from women with intra-amniotic infection/inflammation were also included (n = 9). Peripheral blood mononuclear cells from healthy adults were used as controls (n = 3). Immunophenotyping was performed using flow cytometry.

RESULTS

In the absence of intra-amniotic infection/inflammation, the amniotic fluid contained several immune cell populations between 15 and 40 weeks. Among these immune cells: (i) T cells and ILCs were greater than B cells and natural killer (NK) cells between 15 and 30 weeks; (ii) T cells were most abundant between 15 and 30 weeks; (iii) ILCs were most abundant between 15 and 20 weeks; (iv) B cells were scarce between 15 and 20 weeks; yet, they increased and were constant after 20 weeks; (v) NK cells were greater between 15 and 30 weeks than at term; (vi) ILCs expressed high levels of RORγt, CD161, and CD103 (ie, group 3 ILCs); (vii) T cells expressed high levels of RORγt; (viii) neutrophils increased as gestation progressed; and (ix) monocytes/macrophages emerged after 20 weeks and remained constant until term. All of the amniotic fluid immune cells, except ILCs, were increased in the presence of intra-amniotic infection/inflammation.

CONCLUSION

The amniotic fluid harbors a diverse immune cellular composition during normal and complicated pregnancies.

Are amniotic fluid neutrophils in women with intraamniotic infection and/or inflammation of fetal or maternal origin?

BACKGROUND

Neutrophils are the most abundant white blood cells found in the amniotic cavity of women with intraamniotic infection and/or inflammation. The current belief is that these neutrophils are of fetal origin. However, abundant neutrophils have been found in the amniotic fluid of women with a severe acute maternal inflammatory response but without a severe fetal inflammatory response in the placenta, suggesting that these innate immune cells can also be of maternal origin or a mixture of both fetal and maternal neutrophils.

OBJECTIVE

We sought to investigate the origin of amniotic fluid neutrophils from women with intraamniotic infection and/or inflammation and to correlate these findings with acute histologic maternal and fetal inflammatory responses in the placenta.

STUDY DESIGN

Amniotic fluid was collected from 15 women with suspected intraamniotic infection and/or inflammation (positive microbiological cultures and/or interleukin-6 concentrations ≥2.6 ng/mL). Amniotic fluid neutrophils were purified by fluorescence-activated cell sorting, DNA was extracted, and DNA fingerprinting was performed. DNA fingerprinting was also performed in the umbilical cord and maternal blood DNA. Fluorescence in situ hybridization was assayed in women with male neonates. Blinded placental histopathological evaluations were conducted.

RESULTS

First, DNA fingerprinting revealed that 43% (6/14) of women who underwent a single amniocentesis had mostly fetal neutrophils in the amniotic fluid. Second, DNA fingerprinting showed that 36% (5/14) of the women who underwent a single amniocentesis had predominantly maternal neutrophils in the amniotic fluid. Third, DNA fingerprinting indicated that 21% (3/14) of the women who underwent a single amniocentesis had an evident mixture of fetal and maternal neutrophils in the amniotic fluid. Fourth, DNA fingerprinting revealed that a woman who underwent 2 amniocenteses (patient 15) had fetal neutrophils first, and as infection progressed, abundant maternal neutrophils invaded the amniotic cavity. Fifth, fluorescence in situ hybridization confirmed DNA fingerprinting results by showing that both fetal and maternal neutrophils were present in the amniotic fluid. Sixth, most of the women who had predominantly amniotic fluid neutrophils of fetal origin at the time of collection delivered extremely preterm neonates (71% [5/7]). Seventh, all of the women who had predominantly amniotic fluid neutrophils of maternal origin at the time of collection delivered term or late preterm neonates (100% [6/6]). Eighth, 2 of the women who had an evident mixture of fetal and maternal neutrophils in the amniotic fluid at the time of collection delivered extremely preterm neonates (67% [2/3]), and the third woman delivered a term neonate (33% [1/3]). Finally, most of the women included in this study presented acute maternal and fetal inflammatory responses in the placenta (87% [13/15]).

CONCLUSION

Amniotic fluid neutrophils can be either predominantly of fetal or maternal origin, or a mixture of both fetal and maternal origin, in women with intraamniotic infection and/or inflammation. The findings herein provide evidence that both fetal and maternal neutrophils can invade the amniotic cavity, suggesting that both the fetus and the mother participate in the host defense mechanisms against intraamniotic infection.

MFSD2A Promotes Endothelial Generation of Inflammation-Resolving Lipid Mediators and Reduces Colitis in Mice

BACKGROUND & AIMS

Alterations in signaling pathways that regulate resolution of inflammation (resolving pathways) contribute to pathogenesis of ulcerative colitis (UC). The resolution process is regulated by lipid mediators, such as those derived from the ω-3 docosahexaenoic acid (DHA), whose esterified form is transported by the major facilitator superfamily domain containing 2A (MFSD2A) through the endothelium of brain, retina, and placenta. We investigated if and how MFSD2A regulates lipid metabolism of gut endothelial cells to promote resolution of intestinal inflammation.

METHODS

We performed lipidomic and functional analyses of MFSD2A in mucosal biopsies and primary human intestinal microvascular endothelial cells (HIMECs) isolated from surgical specimens from patients with active, resolving UC and healthy individuals without UC (controls). MFSD2A was knocked down in HIMECs with small hairpin RNAs or overexpressed from a lentiviral vector. Human circulating endothelial progenitor cells that overexpress MFSD2A were transferred to CD1 nude mice with dextran sodium sulfate-induced colitis, with or without oral administration of DHA.

RESULTS

Colonic biopsies from patients with UC had reduced levels of inflammation-resolving DHA-derived epoxy metabolites compared to healthy colon tissues or tissues with resolution of inflammation. Production of these metabolites by HIMECs required MFSD2A, which is required for DHA retention and metabolism in the gut vasculature. In mice with colitis, transplanted endothelial progenitor cells that overexpressed MFSD2A not only localized to the inflamed mucosa but also restored the ability of the endothelium to resolve intestinal inflammation, compared with mice with colitis that did not receive MFSD2A-overexpressing endothelial progenitors.

CONCLUSIONS

Levels of DHA-derived epoxides are lower in colon tissues from patients with UC than healthy and resolving mucosa. Production of these metabolites by gut endothelium requires MFSD2A; endothelial progenitor cells that overexpress MFSD2A reduce colitis in mice. This pathway might be induced to resolve intestinal inflammation in patients with colitis.

Fetal death: an extreme manifestation of maternal anti-fetal rejection

OBJECTIVE

The aim of this study was to determine the association between chronic placental inflammation and amniotic fluid (AF) markers of maternal anti-fetal rejection as well as the presence of microorganisms in the AF fluid of patients with fetal death.

STUDY DESIGN

This cohort study included 40 patients with fetal death whose placentas were examined for chronic inflammatory lesions and whose AF chemokine ligand (CXCL)10 and interleukin (IL)-6 concentrations were determined by immunoassays. AF was processed for bacteria, mycoplasmas and viruses using cultivation and molecular microbiologic techniques (i.e. PCR-ESI/MS).

RESULTS

(1) The most prevalent placental findings were maternal vascular underperfusion (63.2%, 24/38), followed by chronic inflammatory lesions (57.9%, 22/38); (2) chronic chorioamnionitis (18/38) was three times more frequent than villitis of unknown etiology (6/38); (3) an elevated AF CXCL10 concentration (above the 95th centile) was present in 60% of the cases, and a receiver operating characteristics (ROC)-derived cut-off of 2.9 ng/mL had a sensitivity of 73% and a specificity of 75% in the identification of chronic placental inflammatory lesions; (4) only five cases had microbial invasion of the amniotic cavity, and the presence of microorganisms did not correlate with chronic placental inflammation.

CONCLUSION

In women with unexplained fetal death, there is an association between elevated AF CXCL10 and chronic placental inflammatory lesions. Therefore, we conclude that a subset of patients with fetal death may have endured a breakdown of maternal-fetal tolerance, which cannot be attributed to microorganisms in the amniotic cavity.

Dietary Linoleic Acid and Its Oxidized Metabolites Exacerbate Liver Injury Caused by Ethanol via Induction of Hepatic Proinflammatory Response in Mice

Alcoholic liver disease is a major human health problem leading to significant morbidity and mortality in the United States and worldwide. Dietary fat plays an important role in alcoholic liver disease pathogenesis. Herein, we tested the hypothesis that a combination of ethanol and a diet rich in linoleic acid (LA) leads to the increased production of oxidized LA metabolites (OXLAMs), specifically 9- and 13-hydroxyoctadecadienoic acids (HODEs), which contribute to a hepatic proinflammatory response exacerbating liver injury. Mice were fed unsaturated (with a high LA content) or saturated fat diets (USF and SF, respectively) with or without ethanol for 10 days, followed by a single binge of ethanol. Compared to SF+ethanol, mice fed USF+ethanol had elevated plasma alanine transaminase levels, enhanced hepatic steatosis, oxidative stress, and inflammation. Plasma and liver levels of 9- and 13-HODEs were increased in response to USF+ethanol feeding. We demonstrated that primarily 9-HODE, but not 13-HODE, induced the expression of several proinflammatory cytokines in vitro in RAW264.7 macrophages. Finally, deficiency of arachidonate 15-lipoxygenase, a major enzyme involved in LA oxidation and OXLAM production, attenuated liver injury and inflammation caused by USF+ethanol feeding but had no effect on hepatic steatosis. This study demonstrates that OXLAM-mediated induction of a proinflammatory response in macrophages is one of the potential mechanisms underlying the progression from alcohol-induced steatosis to alcoholic steatohepatitis.

Amniotic fluid neutrophils can phagocytize bacteria: A mechanism for microbial killing in the amniotic cavity

PROBLEM

Neutrophils are capable of performing phagocytosis, a primary mechanism for microbial killing. Intra-amniotic infection is characterized by an influx of neutrophils into the amniotic cavity. Herein, we investigated whether amniotic fluid neutrophils could phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection.

METHODS

Amniotic fluid neutrophils from women with intra-amniotic infection were visualized by transmission electron microscopy (n=6). The phagocytic activity of amniotic fluid neutrophils from women with intra-amniotic infection and/or inflammation (n=10) or peripheral neutrophils from healthy individuals (controls, n=3) was tested using ex vivo phagocytosis assays coupled with live imaging. Phagocytosis by amniotic fluid neutrophils was also visualized by confocal microscopy (n=10) as well as scanning and transmission electron microscopy (n=5).

RESULTS

(i) Intra-amniotic infection-related bacteria including cocci (eg Streptococcus agalactiae), bacilli (eg Bacteriodes fragilis and Prevotella spp.), and small bacteria without a cell wall (eg Ureaplasma urealyticum) were found inside of amniotic fluid neutrophils; (ii) peripheral neutrophils (controls) rapidly phagocytized S. agalactiae, U. urealyticum, Gardnerella vaginalis, and Escherichia coli; (iii) amniotic fluid neutrophils rapidly phagocytized S. agalactiae and G. vaginalis; and (iv) amniotic fluid neutrophils slowly phagocytized U. urealyticum and E. coli; yet, the process of phagocytosis of the genital mycoplasma was lengthier.

CONCLUSION

Amniotic fluid neutrophils can phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection, namely S. agalactiae, U. urealyticum, G. vaginalis, and E. coli. Yet, differences in the rapidity of phagocytosis were observed among the studied microorganisms. These findings provide a host defense mechanism whereby amniotic fluid neutrophils can kill microbes invading the amniotic cavity.