Obesity-Related Changes in Human Plasma Lipidome Determined by the Lipidyzer Platform

Lipidomic perturbations of normal-weight adiposity phenotypes and their mediations on diet-adiposity associations

BACKGROUND & AIMS

Normal-weight obesity (NWO) and normal-weight central obesity (NWCO) have been linked to higher cardiometabolic risks, but their etiological bases and attributable dietary factors remain unclear. In this study we therefore aimed to identify lipidomic signatures and dietary factors related to NWO and NWCO and to explore the mediation associations of lipids in diet-adiposity associations.

METHODS

Using a high-coverage targeted lipidomic approach, we quantified 1245 serum lipids in participants with NWO (n = 150), NWCO (n = 150), or propensity-score-matched normal-weight controls (n = 150) based on the Regional Ethnic Cohort Study in Northwest China. Consumption frequency of 28 major food items was recorded using a food frequency questionnaire.

RESULTS

Profound lipidomic perturbations of NWCO relative to NWO were observed, and 249 (dominantly glycerolipids) as well as 48 (dominantly glycerophospholipids) lipids were exclusively associated with NWCO or NWO. Based on strong lipidomic signatures identified by a LASSO model, phospholipid biosynthesis was the top enriched pathway of NWCO, and sphingolipid metabolism was the top pathway of NWO. Remarkably, sphingolipids were positively associated with NWO and NWCO, but lyso-phosphatidylcholines were negatively associated with them. Rice, fruit juice, and carbonated drink intakes were positively associated with the risk of NWCO. Both global and individual lipidomic signatures, including SE(28:1_22:6) and HexCer(d18:1/20:1), mediated these diet-NWCO associations (mediation proportion: 15.92%-26.10%).

CONCLUSIONS

Differential lipidomic signatures were identified for overall and abdominal adiposity accumulation in normal-weight individuals, underlining their core mediation roles in dietary contributions to adiposity deposition.

Relationship between systemic biomarker of lipid peroxidation 4-hydroxynonenal and lipidomic profile of morbidly obese patients undergoing bariatric surgery

Obesity is characterized by fat accumulation, impaired metabolism and oxidative stress, frequently associated with lipid peroxidation and generation of bioactive 4-hydroxynonenal (4-HNE). This study aimed to evaluate the impact of bariatric surgery-induced weight loss on lipid peroxidation and associated perturbations in lipid profile. Plasma samples of twenty obese individuals before and 6 months after bariatric surgery were collected in addition to samples of ten healthy controls. HILIC-LC-MS/MS platform was used to characterize phospholipid profile, while lipid peroxidation markers 15-F2t-IsoP, 10-F4t-NeuroP and reactive aldehyde 4-HNE were quantified by RP-LC-MS/MS and GC-MS, respectively. Six months post-surgery lipid peroxidation markers decreased significantly and the BMI of morbidly obese patients decreased by 13 on average. Lipidomics analysis, identified 117 phospholipid species from seven classes, and showed obesity-associated lipidome perturbations, particularly in ether-linked phosphatidylethanolamines (PEo). A total of 45 lipid species were found to be significantly altered with obesity, while 10 lipid species correlated with lipid peroxidation markers. Sample pairwise analyses indicated an interesting link between 4-HNE and the amount of two PEos, PEo (38:2) and PEo (36:2). The results indicate that weight loss-induced improvement of redox homeostasis together with changes in lipid metabolites may serve as markers of metabolic improvement. However, further studies are needed to understand the role of obesity-induced oxidative stress on ether lipid biosynthesis and lipidome perturbations, as well as the impact of bariatric surgery on metabolic improvement.

Comparison of Adiposomal Lipids between Obese and Non-Obese Individuals

Our recent findings revealed that human adipose tissues (AT)-derived extracellular vesicles (adiposomes) vary in cargo among obese and lean individuals. The main objective of this study was to investigate the adiposomal lipid profiles and their correlation with cardiometabolic risk factors. AT samples were collected from obese subjects and lean controls and analyzed for their characteristics and lipid content. In addition, we measured the correlation between adiposomal lipid profiles and body composition, glucose and lipid metabolic profiles, brachial artery vasoreactivity, AT arteriolar flow-induced dilation, and circulating markers such as IL-6, C-reactive protein, and nitric oxide (NO). Compared to lean controls, adiposomes isolated from obese subjects were higher in number after normalization to AT volume. The two major lipid classes differentially expressed were lysophosphatidylcholine/phosphatidylcholine (LPC/PC) and ceramides (Cer). All lipids in the LPC/PC class were several-fold lower in adiposomes from obese subjects compared to lean controls, on top of which were PC 18:2, PC 18:1, and PC 36:3. Most ceramides were markedly upregulated in the obese group, especially Cer d37:0, Cer d18:0, and Cer d39:0. Regression analyses revealed associations between adiposomal lipid profiles and several cardiometabolic risk factors such as body mass index (BMI), fat percentage, insulin resistance, arteriolar and brachial artery vasoreactivity, NO bioavailability, and high-density lipoproteins (HDL-C). We conclude that the ability of adiposomes from obese subjects to disrupt cardiometabolic function could be partly attributed to the dysregulated lipid cargo.

Cross-Validation of Lipid Structure Assignment Using Orthogonal Ion Activation Modalities on the Same Mass Spectrometer

The onset and progression of cancer is associated with changes in the composition of the lipidome. Therefore, better understanding of the molecular mechanisms of these disease states requires detailed structural characterization of the individual lipids within the complex cellular milieu. Recently, changes in the unsaturation profile of membrane lipids have been observed in cancer cells and tissues, but assigning the position(s) of carbon-carbon double bonds in fatty acyl chains carried by membrane phospholipids, including the resolution of lipid regioisomers, has proven analytically challenging. Conventional tandem mass spectrometry approaches based on collision-induced dissociation of ionized glycerophospholipids do not yield spectra that are indicative of the location(s) of carbon-carbon double bonds. Ozone-induced dissociation (OzID) and ultraviolet photodissociation (UVPD) have emerged as alternative ion activation modalities wherein diagnostic product ions can enable de novo assignment of position(s) of unsaturation based on predictable fragmentation behaviors. Here, for the first time, OzID and UVPD (193 nm) mass spectra are acquired on the same mass spectrometer to evaluate the relative performance of the two modalities for lipid identification and to interrogate the respective fragmentation pathways under comparable conditions. Based on investigations of lipid standards, fragmentation rules for each technique are expanded to increase confidence in structural assignments and exclude potential false positives. Parallel application of both methods to unsaturated phosphatidylcholines extracted from isogenic colorectal cancer cell lines provides high confidence in the assignment of multiple double bond isomers in these samples and cross-validates relative changes in isomer abundance.

Serum Metabolomic and Lipidomic Profiling Reveals the Signature for Postoperative Obesity among Adult-Onset Craniopharyngioma

Craniopharyngioma patients often suffer from a diminished quality of life after surgery, which is usually associated with metabolic disorders and hypothalamic obesity. However, the precise etiology of these conditions remains elusive. To identify the metabolic changes after surgery, we conducted a cross-sectional study using metabolomic and lipidomic analysis to profile metabolic alterations in adult-onset craniopharyngioma patients with postoperative obesity. A cohort of 120 craniopharyngioma patients who had undergone surgery were examined. Differential analyses, including clinical characteristics, serum metabolome, and lipidome, were conducted across distinct body mass index (BMI) groups. Our findings indicated no statistically significant differences in age, sex, and fasting blood glucose among postoperative craniopharyngioma patients when stratified by BMI. However, a noteworthy difference was observed in uric acid and blood lipid levels. Further investigation revealed that alterations in metabolites and lipids were evidently correlated with increased BMI, indicating that postoperative obesity of craniopharyngioma patients affected their whole-body metabolism. Additionally, the multi-omics analysis identified specific metabolites and lipids, including uric acid and DG(18:2/20:4), as contributors to the metabolic disorders associated with postoperative obesity of craniopharyngioma patients. This work provides valuable insight into the involvement of metabolites and lipids in metabolic disorders subsequent to craniopharyngioma surgery.

Metabolic liability for weight gain in early adulthood

While weight gain is associated with a host of chronic illnesses, efforts in obesity have relied on single "snapshots" of body mass index (BMI) to guide genetic and molecular discovery. Here, we study >2,000 young adults with metabolomics and proteomics to identify a metabolic liability to weight gain in early adulthood. Using longitudinal regression and penalized regression, we identify a metabolic signature for weight liability, associated with a 2.6% (2.0%-3.2%, p = 7.5 × 10-19) gain in BMI over ≈20 years per SD higher score, after comprehensive adjustment. Identified molecules specified mechanisms of weight gain, including hunger and appetite regulation, energy expenditure, gut microbial metabolism, and host interaction with external exposure. Integration of longitudinal and concurrent measures in regression with Mendelian randomization highlights the complexity of metabolic regulation of weight gain, suggesting caution in interpretation of epidemiologic or genetic effect estimates traditionally used in metabolic research.

Differential Associations of Erythrocyte Membrane Saturated Fatty Acids with Glycemic and Lipid Metabolic Markers in a Chinese Population: A Cross-Sectional Study

Mounting evidence indicates a complex link between circulating saturated fatty acids (SFAs) and cardiovascular disease (CVD) risk factors, but research on erythrocyte membrane SFA associations with metabolic markers remains limited. Our study sought to investigate the correlations between erythrocyte membrane SFAs and key metabolic markers within glycemic and lipid metabolism in a Chinese population of 798 residents aged 41 to 71 from Guangzhou. Using gas chromatography-mass spectrometry, we assessed the erythrocyte membrane saturated fatty acid profile and performed multiple linear regression to evaluate the relationship between different SFA subtypes and metabolic markers. Our findings revealed that the odd-chain SFA group (C15:0 + C17:0) exhibited negative associations with fasting blood glucose (FBG), homeostatic model assessment for insulin resistance (HOMA-IR), and triglycerides (TG). Conversely, the very-long-chain SFA group (C20:0 + C22:0 + C23:0 + C24:0) exhibited positive associations with fasting insulins (FINS), HOMA-IR, total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C). Furthermore, there was no evidence supporting an association between the even-chain group (C14:0 + C16:0 + C18:0) and metabolic markers. Our findings suggest that different subtypes of SFAs have diverse effects on glycemic and lipid metabolic markers, with odd-chain SFAs associated with a lower metabolic risk. However, the results concerning the correlations between even-chain SFAs and very-long-chain SFAs with markers of glycemic and lipid metabolism pathways are confusing, highlighting the necessity for further exploration and investigation.

Identification of Plasma Lipid Alterations Associated with Melanoma Metastasis

The aim of this study was to apply a state-of-the-art quantitative lipidomic profiling platform to uncover lipid alterations predictive of melanoma progression. Our study included 151 melanoma patients; of these, 83 were without metastasis and 68 with metastases. Plasma samples were analyzed using a targeted Lipidyzer™ platform, covering 13 lipid classes and over 1100 lipid species. Following quality control filters, 802 lipid species were included in the subsequent analyses. Total plasma lipid contents were significantly reduced in patients with metastasis. Specifically, levels of two out of the thirteen lipid classes (free fatty acids (FFAs) and lactosylceramides (LCERs)) were significantly decreased in patients with metastasis. Three lipids (CE(12:0), FFA(24:1), and TAG47:2-FA16:1) were identified as more effective predictors of melanoma metastasis than the well-known markers LDH and S100B. Furthermore, the predictive value substantially improved upon combining the lipid markers. We observed an increase in the cumulative levels of five lysophosphatidylcholines (LPC(16:0); LPC(18:0); LPC(18:1); LPC(18:2); LPC(20:4)), each individually associated with an elevated risk of lymph node metastasis but not cutaneous or distant metastasis. Additionally, seventeen lipid molecules were linked to patient survival, four of which (CE(12:0), CE(14:0), CE(15:0), SM(14:0)) overlapped with the lipid panel predicting metastasis. This study represents the first comprehensive investigation of the plasma lipidome of melanoma patients to date. Our findings suggest that plasma lipid profiles may serve as important biomarkers for predicting clinical outcomes of melanoma patients, including the presence of metastasis, and may also serve as indicators of patient survival.

Quantitative Analysis of Acetyl-CoA, Malonyl-CoA, and Succinyl-CoA in Myocytes

Several analytical challenges make it difficult to accurately measure coenzyme A (CoA) metaboforms, including insufficient stability and a lack of available metabolite standards. Consequently, our understanding of CoA biology and the modulation of human diseases may be nascent. CoA's serve as lipid precursors, energy intermediates, and mediators of post-translational modifications of proteins. Here, we present a liquid chromatography-mass spectrometry (LC-MS) approach to measure malonyl-CoA, acetyl-CoA, and succinyl-CoA in complex biological samples. Additionally, we evaluated workflows to increase sample stability. We used reference standards to optimize CoA assay sensitivity and test CoA metabolite stability as a function of the reconstitution solvent. We show that using glass instead of plastic sample vials decreases CoA signal loss and improves the sample stability. We identify additives that improve CoA stability and facilitate accurate analysis of CoA species across large sample sets. We apply our optimized workflow to biological samples of skeletal muscle cells cultured under hypoxic and normoxia conditions. Together, our workflow improves the detection and identification of CoA species through targeted analysis in complex biological samples.

Metabolic phenotyping of BMI to characterize cardiometabolic risk: evidence from large population-based cohorts

Obesity is a risk factor for type 2 diabetes and cardiovascular disease. However, a substantial proportion of patients with these conditions have a seemingly normal body mass index (BMI). Conversely, not all obese individuals present with metabolic disorders giving rise to the concept of "metabolically healthy obese". We use lipidomic-based models for BMI to calculate a metabolic BMI score (mBMI) as a measure of metabolic dysregulation associated with obesity. Using the difference between mBMI and BMI (mBMIΔ), we identify individuals with a similar BMI but differing in their metabolic health and disease risk profiles. Exercise and diet associate with mBMIΔ suggesting the ability to modify mBMI with lifestyle intervention. Our findings show that, the mBMI score captures information on metabolic dysregulation that is independent of the measured BMI and so provides an opportunity to assess metabolic health to identify "at risk" individuals for targeted intervention and monitoring.

ACSL1 is a key regulator of inflammatory and macrophage foaming induced by short-term palmitate exposure or acute high-fat feeding

Foamy and inflammatory macrophages play pathogenic roles in metabolic disorders. However, the mechanisms that promote foamy and inflammatory macrophage phenotypes under acute-high-fat feeding (AHFF) remain elusive. Herein, we investigated the role of acyl-CoA synthetase-1 (ACSL1) in favoring the foamy/inflammatory phenotype of monocytes/macrophages upon short-term exposure to palmitate or AHFF. Palmitate exposure induced a foamy/inflammatory phenotype in macrophages which was associated with increased ACSL1 expression. Inhibition/knockdown of ACSL1 in macrophages suppressed the foamy/inflammatory phenotype through the inhibition of the CD36-FABP4-p38-PPARδ signaling axis. ACSL1 inhibition/knockdown suppressed macrophage foaming/inflammation after palmitate stimulation by downregulating the FABP4 expression. Similar results were obtained using primary human monocytes. As expected, oral administration of ACSL1 inhibitor triacsin-C in mice before AHFF normalized the inflammatory/foamy phenotype of the circulatory monocytes by suppressing FABP4 expression. Our results reveal that targeting ACSL1 leads to the attenuation of the CD36-FABP4-p38-PPARδ signaling axis, providing a therapeutic strategy to prevent the AHFF-induced macrophage foaming and inflammation.

Plasma lipid metabolites as potential biomarkers for identifying individuals at risk of obesity-induced metabolic complications

Lipidomics studies have indicated an association between obesity and lipid metabolism dysfunction. This study aimed to evaluate and compare cardiometabolic risk factors, and the lipidomic profile in adults and older people. A cross-sectional study was conducted with 72 individuals, divided into two sex and age-matched groups: obese (body mass index-BMI ≥ 30 kg/m2; n = 36) and non-obese (BMI < 30 kg/m2; n = 36). The lipidomic profiles were evaluated in plasma using 1H nuclear magnetic resonance (1H-NMR) spectroscopy. Obese individuals had higher waist circumference (p < 0.001), visceral adiposity index (p = 0.029), homeostatic model assessment insulin resistance (HOMA-IR) (p = 0.010), and triacylglycerols (TAG) levels (p = 0.018). 1H-NMR analysis identified higher amounts of saturated lipid metabolite fragments, lower levels of unsaturated lipids, and some phosphatidylcholine species in the obese group. Two powerful machine learning (ML) models-k-nearest neighbors (kNN) and XGBoost (XGB) were employed to characterize the lipidomic profile of obese individuals. The results revealed metabolic alterations associated with obesity in the NMR signals. The models achieved high accuracy of 86% and 81%, respectively. The feature importance analysis identified signal at 1.50-1.60 ppm (-CO-CH2-CH2-, Cholesterol and fatty acid in TAG, Phospholipids) to have the highest importance in the two models.

LC/MS-Based Untargeted Metabolomics Analysis in Women with Morbid Obesity and Associated Type 2 Diabetes Mellitus

Obesity is a chronic and complex disease, with an increasing incidence worldwide that is associated with metabolic disorders such as type 2 diabetes mellitus (T2DM). Thus, it is important to determine the differences between metabolically healthy obese individuals and those with metabolic disorders. The aim of this study was to perform an untargeted metabolomics assay in women with morbid obesity (MO) compared to a normal weight group, and to differentiate the metabolome of these women with MO who present with T2DM. We carried out a liquid chromatography-mass spectrometry-based untargeted metabolomics assay using serum samples of 209 Caucasian women: 73 with normal weight and 136 with MO, of which 71 had T2DM. First, we found increased levels of choline and acylglycerols and lower levels of bile acids, steroids, ceramides, glycosphingolipids, lysophosphatidylcholines, and lysophosphatidylethanolamines in MO women than in the control group. Then, in MO women with T2DM, we found increased levels of glutamate, propionyl-carnitine, bile acids, ceramides, lysophosphatidylcholine 14:0, phosphatidylinositols and phosphoethanolamines, and lower levels of Phe-Ile/Leu. Thus, we found metabolites with opposite trends of concentration in the two metabolomic analyses. These metabolites could be considered possible new factors of study in the pathogenesis of MO and associated T2DM in women.

Lipidomics Reveals Elevated Plasmalogens in Women with Obesity Who Develop Preeclampsia

Objective: Preeclampsia (PE) is a prevalent pregnancy disorder worldwide with limited preventative treatments available. Obesity triples the risk for PE, yet only 10% of women with obesity develop PE. The factors that distinguish PE from uncomplicated pregnancies in the context of obesity have not been fully established. Methods: We studied a cohort of women with obesity throughout pregnancy to identify lipid mediators and/or biomarkers of PE. Blood samples were collected at each trimester and analyzed by both targeted lipidomics and standard lipid panels. Individual lipid species were compared by PE status at each trimester, as well as by self-identified race (Black vs. White) and fetal sex. Results: Standard lipid panels and clinical measurements revealed few differences between PE and uncomplicated pregnancies. Targeted lipidomics, however, identified plasmalogen, phosphatidylethanolamine, and free fatty acid species that were elevated in the third trimester of women with PE. Furthermore, race and trimester of pregnancy were considerable sources of plasma lipidomic variation in women with obesity. Conclusions: First and second trimester individual plasma lipid species do not predict the development of PE in obese women. In the third trimester, PE patients have elevated levels of plasmalogens-a class of lipoprotein-associated phospholipids that have been implicated in the response to oxidative stress.

Lipid Profiling Reveals Lipidomic Signatures of Weight Loss Interventions

Obesity is an epidemic all around the world. Weight loss interventions that are effective differ from each other with regard to various lipidomic responses. Here, we aimed to find lipidomic biomarkers that are related to beneficial changes in weight loss. We adopted an untargeted liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to measure 953 lipid species for Exercise (exercise intervention cohort, N = 25), 1388 lipid species for LSG (laparoscopic sleeve gastrectomy cohort, N = 36), and 886 lipid species for Cushing (surgical removal of the ACTH-secreting pituitary adenomas cohort, N = 25). Overall, the total diacylglycerol (DG), triacylglycerol (TG), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS), and sphingomyelin (SM) levels were associated with changes in BMI, glycated hemoglobin (HbA1c), triglyceride, and total cholesterol according to weight loss interventions. We found that 73 lipid species changed among the three weight loss interventions. We screened 13 lipid species with better predictive accuracy in diagnosing weight loss situations in either Exercise, LSG, or Cushing cohorts (AUROC > 0.7). More importantly, we identified three phosphatidylcholine (PC) lipid species, PC (14:0_18:3), PC (31:1), and PC (32:2) that were significantly associated with weight change in three studies. Our results highlight potential lipidomic biomarkers that, in the future, could be used in personalized approaches involving weight loss interventions.

Lipidomic analysis of adipose-derived extracellular vesicles reveals specific EV lipid sorting informative of the obesity metabolic state

Adipose extracellular vesicles (AdEVs) transport lipids that could participate in the development of obesity-related metabolic dysfunctions. This study aims to define mouse AdEV lipid signature by a targeted LC-MS/MS approach in either healthy or obesity context. Distinct clustering of AdEV and visceral adipose tissue (VAT) lipidomes by principal component analysis reveals specific AdEV lipid sorting when compared with secreting VAT. Comprehensive analysis identifies enrichment of ceramides, sphingomyelins, and phosphatidylglycerols species in AdEVs compared with source VAT whose lipid content closely relates to the obesity status and is influenced by the diet. Obesity moreover impacts AdEV lipidome, mirroring lipid alterations retrieved in plasma and VAT. Overall, our study identifies specific lipid fingerprints for plasma, VAT, and AdEVs that are informative of the metabolic status. Lipid species enriched in AdEVs in the obesity context may constitute biomarker candidates or mediators of the obesity-associated metabolic dysfunctions.

Abdominal obesity-related lipid metabolites may mediate the association between obesity and glucose dysregulation

BACKGROUND

Children with obesity is associated with a higher risk of cardiovascular disease (CV) risk in adulthood. This study is to explore the obesity-related lipid metabolites and identify the associations of lipid metabolites with selected CV risk in children and adolescents.

METHODS

A case-control study was designed to include a total of 197 children (aged 9-13 years, male 56.34%, 99 children in the obesity group). The lipidomics profiling was measured by ultra-high-performance liquid tandem chromatography quadrupole time-of-flight mass spectrometry.

RESULTS

Four FDR-significant abdominal obesity-related lipid metabolites were identified. Compared to the lean group, decreased phosphatidylcholine O-21:2 level (q = 0.010) and sphingomyelins d21:1 (q = 0.029) were found and two lipid metabolites levels were higher in the obese group, including phosphatidylglycerol 43:6 and one did not match with any candidate compounds in databases. After adjusting for covariates, PC3 (O-21:2) and SM (d21:1) were significantly associated with blood glucose. Mediation analysis showed that all three lipid metabolites may mediate the association between abdominal obesity and glucose regulation.

CONCLUSIONS

This study identified several novel central obesity-related lipid metabolites, and we found that PC3 (O-21:2) and SM (d21:1) were significantly associated with blood glucose, and all these lipid metabolites can mediate the association between abdominal obesity and glucose dysregulation.

IMPACT

Serum lipidomic profiles in children with abdominal obesity and their associations with selected CV risk factors were examined. Our study identified 4 lipid metabolites associated with abdominal obesity, including PC3 (O-21:2), SM (d21:1), PG (43:6), and one did not match with any candidate compounds in the databases. PC3 (O-21:2) and SM (d21:1) were significantly associated with blood glucose. Mediation analysis showed that all three lipid metabolites [PC3 (O-21:2), SM (d21:1), PG (43:6)] may mediate the association between abdominal obesity and abnormal glucose regulation. This study identified several novel obesity-related lipid metabolites.

Metabolic signatures in human follicular fluid identify lysophosphatidylcholine as a predictor of follicular development

In order to investigate the metabolic characteristics of human follicular fluid (FF) and to reveal potential metabolic predictors of follicular development (FD) with clinical implications, we analyzed a total of 452 samples based on a two-stage study design. In the first stage, FF samples from both large follicles (LFs) and matched-small follicles (SFs) of 26 participants were analyzed with wide-spectrum targeted metabolomics. The metabolic signatures were described by multi-omics integration technology including metabolomic data and transcriptomic data. In the second stage, the potential biomarkers of FD were verified using enzyme-linked immunoassay with FF and blood serum from an independent 200 participants. We describe the FF metabolic signatures from ovarian follicles of different developmental stages. Lysophosphatidylcholine (LPC) can be used as a biomarker of FD and ovarian sensitivity, advancing the knowledge of metabolic regulation during FD and offering potential detection and therapeutic targets for follicle and oocyte health improvements in humans.

A two-stage metabolomic analysis for human follicular fluid characteristics and predictors of follicular development yields metabolic signatures and proposes lysophosphatidylcholine (LPC) as a biomarker for follicular development.

Age- and Diet-Dependent Changes in Hepatic Lipidomic Profiles of Phospholipids in Male Mice: Age Acceleration in Cyp2b-Null Mice

Increases in traditional serum lipid profiles are associated with obesity, cancer, and cardiovascular disease. Recent lipidomic analysis has indicated changes in serum lipidome profiles, especially in regard to specific phosphatidylcholines, associated with obesity. However, little work has evaluated murine hepatic liver lipidomic profiles nor compared these profiles across age, high-fat diet, or specific genotypes, in this case the lack of hepatic Cyp2b enzymes. In this study, the effects of age (9 months old), high-fat diet (4.5 months old), and the loss of three primarily hepatic xeno- and endobiotic metabolizing cytochrome P450 (Cyp) enzymes, Cyp2b9, Cyp2b10, and Cyp2b13 (Cyp2b-null mice), on the male murine hepatic lipidome were compared. Hierarchical clustering and principal component analysis show that age perturbs hepatic phospholipid profiles and serum lipid markers the most compared to young mice, followed by a high-fat diet and then loss of Cyp2b. Several lipid biomarkers such as PC/PE ratios, PE 38 : 6, and LPC concentrations indicate greater potential for NAFLD and hypertension with mixed effects in Cyp2b-null mice(less NAFLD and greater hypertension-associated markers). Lipid profiles from older mice contain greater total and n-6 fatty acids than normal diet (ND)-fed young mice; however, surprisingly, young Cyp2b-null mice contain high n-6 : n-3 ratios. Overall, the lack of Cyp2b typically enhanced adverse physiological parameters observed in the older (9 mo) mice with increased weight gain combined with a deteriorating cholesterol profile, but not necessarily all phospholipid profiles were adversely perturbed.

Effects of the Leptin-Mediated MAPK/ERK Signaling Pathway on Collagen II Expression in Knee Cartilage of Newborn Male Mice from Obese Maternal Offspring

Epidemiological data suggest that various noncommunicable diseases develop as a result of altered maternal metabolic and physiological status due to exposure to several adverse factors during pregnancy. However, evidence for intrauterine exposure factors and mechanisms underlying the origin of early cartilage disease in chronic osteoarthritic disease is still lacking. In this study, we found that persistent overnutrition during pregnancy in obese mothers led to cartilage damage in neonatal male mice. This was mainly characterized by increased apoptosis with decreased expression of chondrocyte collagen II and low expression of Runx family transcription factor 2 (RUNX2) and SRY-box transcription factor 9 (SOX9). This reduction was also found to be associated with high leptin expression in newborn male mice of obese maternal offspring. Furthermore, the administration of leptin and mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase (ERK) inhibitors in primary chondrocytes showed that leptin mediated MAPK/ERK signaling activation and thus affected the key regulators of cartilage matrix metallopeptidase 1 (MMP1) and tissue inhibitor of metalloproteinase 1 (TIMP1), thereby altering the expression of collagen II in mouse cartilage. Altogether, this study provided insights into the molecular mechanisms of cartilage-related disease development and also new clues and evidence for the fetogenetic origin of cartilage diseases.

Lipidomic profiling reveals distinct differences in plasma lipid composition in overweight or obese adolescent students

INTRODUCTION

The relationship between dyslipidemia and obesity has been widely reported, but the global lipid profiles associated with the development of obesity still need to be clarified. An investigation into the association between the lipidomic plasma profile and adolescent obesity may provide new insights into the development of obesity.

METHODS

Mass spectrometry coupled with liquid chromatography was applied to detect the global lipidome in the fasting plasma from 90 Chinese adolescents, including 34 obese adolescents, 26 overweight adolescents, and 30 adolescents with a normal body mass index (BMI). All participants underwent anthropometric measurements by using InBody. Clinical biochemical indicators were measured by Cobas Elecsys.

RESULTS

Both qualitative and quantitative analyses revealed a gradual change in plasma lipid features among obese students, exhibiting characteristics close to overweight students, but differing significantly from normal students. Compared with normal and overweight students, levels of triglyceride (TG), 18-hydroxycortisol, isohumulinone A, and 11-dihydro-12-norneoquassin were up-regulated in the obese group, while phosphatidylcholine (PC), phosphatidylethanolamine (PE), lysoPC (LPC), lysoPE (LPE), and phosphatidylinositol (PI) were significantly down-regulated in the obese group. Then, we conducted Venn diagrams and selected 8 significant metabolites from the 3 paired comparisons. Most of the selected features were significantly correlated with the anthropometric measurements.

CONCLUSIONS

This study demonstrated evidence for a relationship between the eight significant metabolites with obese adolescents. These lipid features may provide a basis for evaluating risk and monitoring the development of obesity.

Autotaxin-LPA-LPP3 Axis in Energy Metabolism and Metabolic Disease

Besides serving as a structural membrane component and intermediate of the glycerolipid metabolism, lysophosphatidic acid (LPA) has a prominent role as a signaling molecule through its binding to LPA receptors at the cell surface. Extracellular LPA is primarily produced from lysophosphatidylcholine (LPC) through the activity of secreted lysophospholipase D, autotaxin (ATX). The degradation of extracellular LPA to monoacylglycerol is mediated by lipid phosphate phosphatases (LPPs) at the cell membrane. This review summarizes and interprets current literature on the role of the ATX-LPA-LPP3 axis in the regulation of energy homeostasis, insulin function, and adiposity at baseline and under conditions of obesity. We also discuss how the ATX-LPA-LPP3 axis influences obesity-related metabolic complications, including insulin resistance, fatty liver disease, and cardiomyopathy.

Evaluation of two highly effective lipid-lowering therapies in subjects with acute myocardial infarction

For cardiovascular disease prevention, statins alone or combined with ezetimibe have been recommended to achieve low-density lipoprotein cholesterol targets, but their effects on other lipids are less reported. This study was designed to examine lipid changes in subjects with ST-segment elevation myocardial infarction (STEMI) after two highly effective lipid-lowering therapies. Twenty patients with STEMI were randomized to be treated with rosuvastatin 20 mg QD or simvastatin 40 mg combined with ezetimibe 10 mg QD for 30 days. Fasting blood samples were collected on the first day (D1) and after 30 days (D30). Lipidomic analysis was performed using the Lipidyzer platform. Similar classic lipid profile was obtained in both groups of lipid-lowering therapies. However, differences with the lipidomic analysis were observed between D30 and D1 for most of the analyzed classes. Differences were noted with lipid-lowering therapies for lipids such as FA, LPC, PC, PE, CE, Cer, and SM, notably in patients treated with rosuvastatin. Correlation studies between classic lipid profiles and lipidomic results showed different information. These findings seem relevant, due to the involvement of these lipid classes in crucial mechanisms of atherosclerosis, and may account for residual cardiovascular risk.

Randomized clinical trial: ClinicalTrials.gov, NCT02428374, registered on 28/09/2014.