Pediatric Multi-Organ Dysfunction Syndrome: Analysis by an Untargeted “Shotgun” Lipidomic Approach Reveals Low-Abundance Plasma Phospholipids and Dynamic Recovery over 8-Day Period,a Single-Center Observational Study

Lipids are molecules involved in metabolism and inflammation. This study investigates the plasma lipidome for markers of severity and nutritional status in critically ill children. Children with multi-organ dysfunction syndrome (MODS) (n = 24) are analyzed at three time-points and cross-referenced to sedation controls (n = 4) for a total of N = 28. Eight of the patients with MODS, needed veno-arterial extracorporeal membrane oxygenation (VA ECMO) support to survive. Blood plasma lipid profiles are quantified by nano-electrospray (nESI), direct infusion high resolution/accurate mass spectrometry (MS), and tandem mass spectrometry (MS/MS), and compared to nutritional profiles and pediatric logistic organ dysfunction (PELOD) scores. Our results show that PELOD scores were not significantly different between MODS and ECMO cases across time-points (p = 0.66). Lipid profiling provides stratification between sedation controls and all MODS patients for total lysophosphatidylserine (lysoPS) (p-value = 0.004), total phosphatidylserine (PS) (p-value = 0.015), and total ether-linked phosphatidylethanolamine (ether-PE) (p-value = 0.03) after adjusting for sex and age. Nutrition intake over time did not correlate with changes in lipid profiles, as measured by caloric and protein intake. Lipid measurement in the intensive care environment shows dynamic changes over an 8-day pediatric intensive care unit (PICU) course, suggesting novel metabolic indicators for defining critically ill children.     

Sexual dimorphism in hepatic lipids is associated with the evolution of metabolic status in mice

Ectopic lipid accumulation in the liver is implicated in metabolic disease in an age‐ and sex‐dependent manner. The role of hepatic lipids has been well established within the scope of metabolic insults in mice, but has been insufficiently characterized under standard housing conditions, where age‐related metabolic alterations are known to occur. We studied a total of 10 male and 10 female mice longitudinally. At 3, 7 and 11 months of age, non‐invasive ¹H‐magnetic resonance spectroscopy (¹H‐MRS) was used to monitor hepatic lipid content (HLC) and fatty acid composition in vivo, and glucose homeostasis was assessed with glucose and insulin challenges. At the end of the study, hepatic lipids were comprehensively characterized by nuclear magnetic resonance (NMR) and liquid chromatography‐mass spectrometric analyses of liver tissue samples. In males, HLC increased from 1.4 ± 0.1% at 3 months to 2.9 ± 0.3% at 7 months (p < 0.01) and 2.7 ± 0.3% at 11 months (p < 0.05), in correlation with fasting insulin levels (p < 0.01, r = 0.51) and parameters from the insulin tolerance test (ITT; p < 0.001, r = –0.69 versus area under the curve; p < 0.01, r = –0.57 versus blood glucose drop at 1 h post‐ITT; p < 0.01, r = 0.55 versus blood glucose at 3 h post‐ITT). The metabolic performance of females remained the same throughout the study, and HLC was higher than that of males at 3 months (2.7 ± 0.2%, p < 0.01), but comparable at 7 months (2.2 ± 0.2%) and 11 months (2.2 ± 0.1%). Strong sexual dimorphism in bioactive lipid species, including diacylglycerols (higher in males, p < 0.0001), phosphatidylinositols (higher in females, p < 0.001) and omega‐3 polyunsaturated fatty acids (higher in females, p < 0.01), was found to be in good correlation with metabolic scores at 11 months. Therefore, in mice housed under standard conditions, sex‐specific composition of bioactive lipids is associated with metabolic protection in females, whose metabolic performance was independent of hepatic cytosolic lipid content.     

中国脂质组学研究现状的文献计量学分析

2014年12月16日,《中国学术期刊(光盘版)》电子杂志社有限公司、中国科学技术文献评价研究中心和清华大学图书馆在清华大学新学堂举行了"2014中国最具国际影响力学术期刊暨中国学术期刊国际、国内引证报告发布会"。天津中医药大学主办的《天津中医药大学学报》和《天津中医药》两本期刊在主编张伯礼院士悉心指导下,在编辑部全体人员共同努力下,均取得     

Increased PUFA Content and 5-Lipoxygenase Pathway Expression Are Associated with Subcutaneous Adipose Tissue Inflammation in Obese Women with Type 2 Diabetes

Obese women with type 2 diabetes mellitus (T2DM) have more inflammation in their subcutaneous white adipose tissue (sWAT) than age-and-BMI similar obese women with normal glucose tolerance (NGT). We aimed to investigate whether WAT fatty acids and/or oxylipins are associated with the enhanced inflammatory state in WAT of the T2DM women. Fatty acid profiles were measured in both subcutaneous and visceral adipose tissue (vWAT) of 19 obese women with NGT and 16 age-and-BMI similar women with T2DM. Oxylipin levels were measured in sWAT of all women. Arachidonic acid (AA) and docosahexaenoic acid (DHA) percentages were higher in sWAT, but not vWAT of the T2DM women, and AA correlated positively to the gene expression of macrophage marker CD68. We found tendencies for higher oxylipin concentrations of the 5-LOX leukotrienes in sWAT of T2DM women. Gene expression of the 5-LOX leukotriene biosynthesis pathway was significantly higher in sWAT of T2DM women. In conclusion, AA and DHA content were higher in sWAT of T2DM women and AA correlated to the increased inflammatory state in sWAT. Increased AA content was accompanied by an upregulation of the 5-LOX pathway and seems to have led to an increase in the conversion of AA into proinflammatory leukotrienes in sWAT.     

Phospholipase A2 regulates eicosanoid class switching during inflammasome activation

Initiation and resolution of inflammation are considered to be tightly connected processes. Lipoxins (LX) are proresolution lipid mediators that inhibit phlogistic neutrophil recruitment and promote wound-healing macrophage recruitment in humans via potent and specific signaling through the LXA₄ receptor (ALX). One model of lipoxin biosynthesis involves sequential metabolism of arachidonic acid by two cell types expressing a combined transcellular metabolon. It is currently unclear how lipoxins are efficiently formed from precursors or if they are directly generated after receptor-mediated inflammatory commitment. Here, we provide evidence for a pathway by which lipoxins are generated in macrophages as a consequence of sequential activation of toll-like receptor 4 (TLR4), a receptor for endotoxin, and P2X₇, a purinergic receptor for extracellular ATP. Initial activation of TLR4 results in accumulation of the cyclooxygenase-2–derived lipoxin precursor 15-hydroxyeicosatetraenoic acid (15-HETE) in esterified form within membrane phospholipids, which can be enhanced by aspirin (ASA) treatment. Subsequent activation of P2X₇ results in efficient hydrolysis of 15-HETE from membrane phospholipids by group IVA cytosolic phospholipase A₂, and its conversion to bioactive lipoxins by 5-lipoxygenase. Our results demonstrate how a single immune cell can store a proresolving lipid precursor and then release it for bioactive maturation and secretion, conceptually similar to the production and inflammasome-dependent maturation of the proinflammatory IL-1 family cytokines. These findings provide evidence for receptor-specific and combinatorial control of pro- and anti-inflammatory eicosanoid biosynthesis, and potential avenues to modulate inflammatory indices without inhibiting downstream eicosanoid pathways.A complex network of danger-sensing receptors and bioactive peptide and lipid signals, including cytokines and eicosanoids, regulates innate immunity. Toll-like receptor (TLR) priming is suggested as a precautionary step in building a significant inflammatory response by driving production of IL-1 family protokines, which remain inactive until a second stimulus drives them to bioactive maturation and secretion (1). The second step of this process has been most strongly linked to extracellular ATP and specifically to one of its purinergic receptors, P2X₇ (2, 3), particularly in macrophages (4).TLR stimulations also increase prostaglandin synthesis by activating cytosolic phospholipase A₂ (cPLA₂) through a Ca²⁺-independent mechanism to release arachidonic acid (AA) from phospholipids, and by increasing expression of cyclooxygenase-2 (COX-2) and microsomal prostaglandin E₂ synthase-1. P2X₇ stimulation activates cPLA₂ through a Ca²⁺-dependent mechanism that couples AA metabolism with 5-lipoxygenase (5-LOX)-activating protein (FLAP), Ca²⁺-activated 5-LOX, and constitutive COX-1 to form leukotrienes (LTs) and prostaglandins (PGs). Short-term (∼1 h) TLR priming of Ca²⁺ ionophore/P2X₇-activated immune cells enhances LT synthesis (5, 6), but long-term TLR priming (16–18 h) significantly suppresses LT synthesis by different cell-type–specific mechanisms (7, 8).Whereas PGE₂, PGI₂, and LTC₄ promote local edema from postcapillary venules, and LTB₄ amplifies neutrophil recruitment to initiate pathogenic killing, subsequent “class switching” to lipoxin (LX) formation by “reprogrammed” neutrophils inhibits additional neutrophil recruitment during self-resolving inflammatory resolution (9). The direct link between inflammatory commitment and resolution mediated by eicosanoid signaling in macrophages remains unclear from short-term vs. long-term priming, but the complete temporal changes and important interconnections within the entire eicosadome are now demonstrated.     

Comprehensive lipid profiling of bleomycin‐induced lung injury

Drug‐induced lung injury is an adverse effect of drug treatment that can result in respiratory failure. Because lipid profiling could provide cutting‐edge understanding of the pathophysiology of toxicological responses, we performed lipidomic analyses of drug‐induced lung injury. We used a mouse model of bleomycin‐induced lung injury and followed the physiological responses at the acute inflammatory (day 2), inflammatory‐to‐fibrosis (day 7) and fibrosis (day 21) phases. The overall lipid profiles of plasma, lung and bronchoalveolar lavage fluid (BALF) revealed that drastic changes in lipids occurred in the lung and BALF, but not in the plasma, after 7 and 21 days of bleomycin treatment. In the lung, the levels of ether‐type phosphatidylethanolamines decreased, while those of phosphatidylcholines, bismonophosphatidic acids and cholesterol esters increased on days 7 and 21. In BALF, the global lipid levels increased on days 7 and 21, but only those of some lipids, such as phosphatidylglycerols/bismonophosphatidic acids and phosphatidylinositols, increased from day 2. The lung levels of prostaglandins, such as prostaglandin D₂, were elevated on day 2, and those of 5‐ and 15‐lipoxygenase metabolites of docosahexaenoic acid were elevated on day 7. In BALF, the levels of 12‐lipoxygenase metabolites of polyunsaturated fatty acids were elevated on day 7. Our comprehensive lipidomics approach suggested anti‐inflammatory responses in the inflammatory phase, phospholipidosis and anti‐inflammatory responses in the inflammatory‐to‐fibrosis phase, and increased oxidative stress and/or cell phenotypic transitions in the fibrosis phase. Understanding these molecular changes and potential mechanisms will help develop novel drugs to prevent or treat drug‐induced lung injury.     

基于UPLC-Q/TOF-MS的丹参-川芎对局灶性脑缺血大鼠保护作用的脂质组学研究

目的研究丹参-川芎水煎液冻干物对局灶性脑缺血模型大鼠脂质代谢异常的调节作用。方法采用线栓法复制大鼠局灶性脑缺血模型,将SD大鼠随机分为对照组、假手术组、模型组及丹参-川芎干预组。末次给药后采集血浆,采用超高效液相色谱四级杆飞行时间质谱联用仪(UPLC-Q/TOF-MS)进行血浆脂质组学研究,采用正交偏最小二乘判别分析(OPLS-DA)处理脂质组学数据,考察丹参-川芎干预前后脂质代谢物组变化。结果成功复制了大鼠局灶性脑缺血模型,丹参-川芎水煎液冻干物对局灶性脑缺血大鼠异常脂质代谢表现出明显的改善作用,大鼠脑缺血损伤血浆脂质标志物为PS(21:0/0:0)、PG(12:0/17:0)、C16 sphinganine,phytosphingosine、PE [18:1(9Z)/0:0]、PC(16:1/2:0)、PC(0:0/18:0)、PC(16:1/0:0)、PC(16:0/0:0)、PC(18:2/0:0)、PC(18:1/0:0)、PC(18:0/0:0)、PC(20:5/0:0)。结论丹参川芎水煎液冻干物具有脑缺血损伤保护作用,其机制可能与其对脂质,尤其是磷脂酰胆碱(PC)的调节有关。     

Lipidomics: New approaches to the studies of cell signaling and prospects of use in medicine

A new modern stage in the development of lipid biochemistry is presented: lipidomics, which emerged on the basic of new highly sensitive fractionation methods, primarily, mass spectroscopy. Lipidomics is defined mainly as systemic evaluation of all molecular types of lipids in an object, their cell functions, and molecules with which they react. Lipidomic approaches identifying picomole levels of individual lipids in combination with modern genome technology provide detailed information about the involvement of minor phospholipids in the cell signaling processes. Brief data on the functions of lysophospholipids as second messengers of signal transfer, their effects on cell processes, and possible involvement in the pathogenesis of some diseases are presented. It is expected that introduction of lipidomics in biomedical studies will promote the detection of targets for new drugs and development of new diagnostic tests. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Supplement 2, pp. 33–38, April, 2007     

苯溴马隆对高尿酸血症模型大鼠脂质代谢的影响

目的 基于脂质组学方法研究苯溴马隆治疗高尿酸血症（hyperuricemia,HUA）大鼠的作用机制,并揭示尿酸水平增高与脂质代谢异常的内在相关性。方法 利用超高效液相色谱-四极杆飞行时间质谱（UPLC-Q-TOF/MS）技术,结合主成分分析（PCA）和偏最小二乘法判别分析（OPLS-DA）研究正常组、模型组和苯溴马隆组的大鼠血清中内源性脂质代谢物的变化,寻找潜在生物标记物,分析相关代谢通路,绘制代谢网络机制图。结果 脂质组学分析发现,苯溴马隆可使HUA大鼠体内水平异常的20个差异代谢物回调到正常水平;相关代谢通路分析发现,苯溴马隆影响果糖诱导HUA大鼠血清中的脂质水平,主要与甘油磷脂代谢通路相关。结论 苯溴马隆对HUA的治疗可能与改善体内甘油磷脂代谢通路异常密切相关。