Levels of lipid-derived gut microbial metabolites differ among plant matrices in an in vitro model of colon fermentation

This study explored differences in microbial lipid metabolites among sunflower seeds, soybeans, and walnuts. The matrices were subjected to in vitro digestion and colonic fermentation. Defatted digested materials and fiber/phenolics extracted therefrom were added to sunflower oil (SO) and also fermented. Targeted and untargeted lipidomics were employed to monitor and tentatively identify linoleic acid (LA) metabolites. Walnut fermentation produced the highest free fatty acids (FFAs), LA, and conjugated LAs (CLAs). Defatted digested walnuts added to SO boosted FFAs and CLAs production; the addition of fibre boosted CLAs, whereas the addition of phenolics only increased 9e,11z-CLA and 10e,12z-CLA. Several di-/tri-hydroxy-C18-FAs, reported as microbial LA metabolites for the first time, were annotated. Permutational multivariate analysis of variance indicated significant impacts of food matrix presence and type on lipidomics and C18-FAs. Our findings highlight how the food matrices affect CLA production from dietary lipids, emphasizing the role of food context in microbial lipid metabolism.

Lipid metabolites, interleukin-6 and oxidative stress markers in follicular fluid and their association with serum concentrations in mares

The application of trans-vaginal ovum pick up (OPU) and intracytoplasmic sperm injection (ICSI) is well established for commercial in vitro embryo production in horses. These assisted reproductive techniques are especially applied during the non-breeding season of the mare. However, little is known about how the health of the oocyte donor may affect the biochemical composition of the follicular fluid (FF) in small and medium-sized follicles routinely aspirated during OPU. This study aimed to investigate associations between systemic and FF concentrations of interleukin-6 (IL-6), total cholesterol, triglycerides, non-esterified fatty acids (NEFA), reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), and oxidative stress index (OSI) during the non-breeding season in mares. At the slaughterhouse, serum and FF of small (5-10 mm in diameter), medium (> 10-20 mm in diameter), and large (> 20-30 mm in diameter) follicles were sampled from 12 healthy mares. There was a strong positive association (P < 0.01) between the concentration of IL-6 in serum and those measured in small (r = 0.846), medium (r = 0.999), and large (r = 0.996) follicles. Serum concentrations of NEFA were positively correlated (P < 0.05) with those measured in small (r = 0.726), medium (r = 0.720), and large (r = 0.974) follicles. Values of total cholesterol and OSI in serum and medium follicles were significantly associated (r = 0.736 and r = 0.696, respectively). The serum concentrations of all lipid metabolites were markedly higher than those measured in FF of small- and medium-sized follicles. Values of IL-6 and OSI did not change significantly between serum and all follicle classes (P ≥ 0.05). To conclude, changes in the blood composition associated with inflammation, oxidative stress, and disturbed lipid metabolism of mares may lead to an inadequate oocyte microenvironment, which could affect oocyte quality and the success rate of OPU/ICSI programs. Further research should indicate whether these changes may ultimately affect in vitro oocyte developmental capacity and subsequent embryo quality.

HD-Zip IV transcription factors: Drivers of epidermal cell fate integrate metabolic signals

The leaf epidermis comprises the outermost layer of cells that protect plants against environmental stresses such as drought, ultraviolet radiation, and pathogen attack. Research over the past decades highlights the role of class IV homeodomain leucine-zipper (HD-Zip IV) transcription factors (TFs) in driving differentiation of various epidermal cell types, such as trichomes, guard cells, and pavement cells. Evolutionary origins of this family in the charophycean green algae and HD-Zip-specific gene expression in the maternal genome provide clues to unlocking their secrets which include ties to cell cycle regulation. A distinguishing feature of these TFs is the presence of a lipid binding pocket that integrates metabolic information with gene expression. Identities of metabolic partners are beginning to emerge, uncovering feedback loops to maintain epidermal cell specification. Discoveries of associated molecular mechanisms are revealing fascinating links to phospholipid and sphingolipid metabolism and mechanical signaling.

Lipidomics reveals the lipid metabolism disorders in Fructus Psoraleae-induced hepatotoxicity in rats with kidney-yin deficiency syndrome

Fructus Psoraleae (FP), one of the important traditional Chinese medicines, is widely used in clinic and has been reported to be hepatotoxic. However, there is no report on the mechanism of FP-induced hepatotoxicity based on the theory of You Gu Wu Yun. In this study, plasma samples of rats with different kidney deficiency syndromes were investigated using a lipidomics approach based on UPLC/Q-TOF-MS technique. Firstly, multivariate statistical analysis, VIP value test, statistical test and other methods were used to find the lipid metabolites in the two syndrome model groups that were different from the normal group. The screening of differential lipid metabolites revealed that there were 12 biomarkers between the blank group and the kidney-yang deficiency model group as well as 16 differential metabolites between the kidney-yin deficiency model group, and finally a total of 17 relevant endogenous metabolites were identified, which could be used as differential lipid metabolites to distinguish between kidney-yin deficiency and kidney-yang deficiency evidence. Secondly, the relative content changes of metabolites in rats after administration of FP decoction were further compared to find the substances associated with toxicity after administration, and the diagnostic ability of the identified biomarkers was evaluated using a receiver operating characteristic curve (ROC). Results a total of 14 potential differential lipid metabolites, including LysoPC(20:0/0:0) and LysoPC(16:0/0:0), which may be related to hepatotoxicity in rats with kidney-yin deficiency syndrome were further screened, namely, the potential active lipid metabolites related to hepatotoxicity in rats induced by FP. Finally, cluster analysis, MetPA analysis and KEGG database were used to analyze metabolic pathways. It was discovered that the metabolism of glycerophospholipid and sphingolipid may be strongly related to the mechanism of hepatotoxicity brought on by FP. Overall, we described the lipidomics changes in rats treated with FP decoction and screened out 14 lipid metabolites related to hepatotoxicity in rats with kidney-yin deficiency, which served as a foundation for the theory of "syndrome differentiation and treatment" in traditional Chinese medicine and a guide for further investigation into the subsequent mechanism.

The relationship between unique gut microbiome-derived lipid metabolites and subsequent revascularization in patients who underwent percutaneous coronary intervention

BACKGROUND AND AIMS

Studies have recently revealed the linoleic acid metabolic pathway of Lactobacillus plantarum, the representative gut bacterium in human gastrointestinal tract, and the anti-inflammatory effects of metabolites in this pathway. However, no clinical trials have evaluated the association between these metabolites and revascularization in patients who underwent percutaneous coronary intervention (PCI).

METHODS

We retrospectively reviewed patients who underwent PCI with subsequent revascularization or coronary angiography (CAG) without revascularization. Patients with frozen blood samples at the index PCI and revascularization or follow-up CAG were enrolled.

RESULTS

Among 701 consecutive patients who underwent PCI, we enrolled 53 patients who underwent subsequent revascularization and 161 patients who underwent follow-up CAG without revascularization. Patients who underwent revascularization showed significantly lower plasma 10-oxo-octadecanoic acid (KetoB) levels (720.5 [551.6-876.5] vs. 818.4 [641.1-1103.6 pg/mL]; p = 0.01) at index PCI. Multivariate logistic regression analysis revealed that decreased plasma KetoB levels at the index PCI were independently associated with subsequent revascularization after PCI (odds ratio; 0.90 per 100 pg/mL increase, 95% confidence interval; 0.82-0.98). Additionally, in vitro experiments showed that the addition of purified KetoB suppressed the mRNA levels of IL-6 and IL-1β in macrophages and IL-1β mRNA in neutrophils.

CONCLUSIONS

Plasma KetoB level at index PCI was independently associated with subsequent revascularization after PCI, and KetoB could act as an anti-inflammatory lipid mediator in macrophages and neutrophils. The assessment of gut microbiome-derived metabolites may help predict revascularization after PCI.

Identification of three potential novel biomarkers for early diagnosis of acute ischemic stroke via plasma lipidomics

INTRODUCTION

Acute ischemic stroke (AIS) accounts for the majority of all stroke, globally the second leading cause of death. Due to its rapid development after onset, its early diagnosis is crucial.

OBJECTIVES

We aim to identify potential highly reliable blood-based biomarkers for early diagnosis of AIS using quantitative plasma lipid profiling via a machine learning approach.

METHODS

Lipidomics was used for quantitative plasma lipid profiling, based on ultra-performance liquid chromatography tandem mass spectrometry. Our samples were divided into a discovery and a validation set, each containing 30 AIS patients and 30 health controls (HC). Differentially expressed lipid metabolites were screened based on the criteria VIP > 1, p < 0.05, and fold change > 1.5 or < 0.67. The least absolute shrinkage and selection operator (LASSO) and random forest algorithms in machine learning were used to select differential lipid metabolites as potential biomarkers.

RESULTS

Three key differential lipid metabolites, CarnitineC10:1, CarnitineC10:1-OH and Cer(d18:0/16:0), were identified as potential biomarkers for early diagnosis of AIS. The former two, associated with thermogenesis, were down-regulated, whereas the latter, associated with necroptosis and sphingolipd metabolism, was upregulated. Univariate and multivariate logistic regressions showed that these three lipid metabolites and the resulting diagnostic model exhibited a strong ability in discriminating between AIS patients and HCs in both the discovery and validation sets, with an area under the curve above 0.9.

CONCLUSIONS

Our work provides valuable information on the pathophysiology of AIS and constitutes an important step toward clinical application of blood-based biomarkers for diagnosing AIS.

Role of omega-3 and omega-6 endocannabinoids in cardiopulmonary pharmacology

Endocannabinoids are derived from dietary omega-3 and omega-6 fatty acids and play an important role in regulation of inflammation, development, neurodegenerative diseases, cancer, and cardiovascular diseases. They elicit this effect via interactions with cannabinoid receptors 1 and 2 which are also targeted by plant derived cannabinoid from cannabis. The evidence of the involvement of the endocannabinoid system in cardiopulmonary function comes from studies that show that cannabis consumption leads to cardiovascular effect such as arrythmia and is beneficial in lung cancer patients. Moreover, omega-3 and omega-6 endocannabinoids play several important roles in cardiopulmonary system such as causing airway relaxation, suppressing atherosclerosis and hypertension. These effects are mediated via the cannabinoids receptors that are abundant in the cardiopulmonary system. Overall, this chapter reviews the known role of phytocannabinoids and endocannabinoids in the cardiopulmonary context.

Comprehensive analysis of lipid metabolism in influenza virus infection

Influenza A virus (IAV) exploits host metabolic pathways to support its replication. To improve the understanding of lipid metabolic changes that could occur upon IAV infection, a comprehensive analysis of lipid metabolites in A549 cells infected with the avian H9N2 virus at the different time points was performed. It was found that H9N2 infection could largely promote the level of lipid metabolites. Further, these metabolites were mainly included in glycerophospholipids (GPs), sphingolipids (SPs), glycerolipids (GLs), fatty acids (FAs), sterollipids (STs), triglycerides (TGs), and prenol lipids (PRs). Specifically, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that these metabolites were mainly associated with the glycerphospholipid metabolism, glycosylphosphatidylinositol (GPI)-anchor biosynthesis, and autophagy. Furthermore, it is interesting to note that these metabolites, including FFA(19:1), PE(P-17:0_20:3), PE(P-18:1_20:2), LPC(14:0/0:0), PE(O-18:0_20:3), and MGDG(16:0_18:1), are upregulated and shared in the top 10 at 12 h, 24 h, 36 h, and 48 h after H9N2 infection, indicative of the possibility of acting as biomarkers for the diagnosis in the lung infected with influenza virus. These pathways and altered metabolites could provide new understandings about biological characteristics and pathogenicity of influenza virus and have the potential to serve as biomarkers for influenza.

A biological rationale for the disparate effects of omega-3 fatty acids on cardiovascular disease outcomes

The omega-3 fatty acids (n3-FAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) rapidly incorporate into cell membranes where they modulate signal transduction pathways, lipid raft formation, and cholesterol distribution. Membrane n3-FAs also form specialized pro-resolving mediators and other intracellular oxylipins that modulate inflammatory pathways, including T-cell differentiation and gene expression. Cardiovascular (CV) trials have shown that EPA, administered as icosapent ethyl (IPE), reduces composite CV events, along with plaque volume, in statin-treated, high-risk patients. Mixed EPA/DHA regimens have not shown these benefits, perhaps as the result of differences in formulation, dosage, or potential counter-regulatory actions of DHA. Indeed, EPA and DHA have distinct, tissue-specific effects on membrane structural organization and cell function. This review summarizes: (1) results of clinical outcome and imaging trials using n3-FA formulations; (2) membrane interactions of n3-FAs; (3) effects of n3-FAs on membrane oxidative stress and cholesterol crystalline domain formation during hyperglycemia; (4) n3-FA effects on endothelial function; (5) role of n3-FA-generated metabolites in inflammation; and (6) ongoing and future clinical investigations exploring treatment targets for n3-FAs, including COVID-19.

Targeted plasma metabolomics in resuscitated comatose out-of-hospital cardiac arrest patients

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a leading cause of death. Even if successfully resuscitated, mortality remains high due to ischemic and reperfusion injury (I/R). The oxygen deprivation leads to a metabolic derangement amplified upon reperfusion resulting in an uncontrolled generation of reactive oxygen species in the mitochondria triggering cell death mechanisms. The understanding of I/R injury in humans following OHCA remains sparse, with no existing treatment to attenuate the reperfusion injury.

AIM

To describe metabolic derangement in patients following resuscitated OHCA.

METHODS

Plasma from consecutive resuscitated unconscious OHCA patients drawn at hospital admission were analyzed using ultra-performance-liquid-mass-spectrometry. Sixty-one metabolites were prespecified for quantification and studied.

RESULTS

In total, 163 patients were included, of which 143 (88%) were men, and the median age was 62 years (53-68). All measured metabolites from the tricarboxylic acid (TCA) cycle were significantly higher in non-survivors vs. survivors (180-days survival). Hierarchical clustering identified four clusters (A-D) of patients with distinct metabolic profiles. Cluster A and B had higher levels of TCA metabolites, amino acids and acylcarnitine species compared to C and D. The mortality was significantly higher in cluster A and B (A:62% and B:59% vs. C:21 % and D:24%, p < 0.001). Cluster A and B had longer time to return of spontaneous circulation (A:33 min (21-43), B:27 min (24-35), C:18 min (13-28), and D:18 min (12-25), p < 0.001).

CONCLUSION

Circulating levels of metabolites from the TCA cycle best described the variance between survivors and non-survivors. Four different metabolic phenotypes with significantly different mortality were identified.

Ethnic differences in ApoC-III concentration and the risk of cardiovascular disease: No evidence for the cardioprotective role of rare/loss of function APOC3 variants in non-Europeans

BACKGROUND

Hypertriglyceridemia is as an independent risk factor for cardiovascular disease (CVD). Apolipoprotein C-III (ApoC-III) is known to regulate triglyceride (TG) metabolism. However, the causal association between ApoC-III and CVD development is unclear. The objectives were to examine the impact of ApoC-III concentration on TG and lipoproteins and investigate the role of known rare loss-of-function APOC3 variants for modulating ApoC-III, TG concentrations and CVD risk in different ethnic groups.

METHODS

Plasma ApoC-III levels were measured in a multiethnic sample of 518 individuals comprising 271 Asian Indians (Sikhs), 87 Caucasians, 80 African Americans, and 80 Hispanics.

RESULTS

ApoC-III levels showed a robust association with TG in Asian Indians (r = 0.5, p = 1.1 × 10^-23), Caucasians (r = 0.4, p = 7.2 × 10^-4), and Hispanics (r = 0.9, p = 2.7x × 10^-28). African Americans had lowest ApoC-III and TG concentrations and highest (44%) prevalence of coronary artery disease (CAD). ApoC-III levels correlated with fasting blood glucose (r = 0.25, p = 6.1 × 10^-5) in Asian Indians and central adiposity in Hispanics (waist: r = 0.22, p = 0.05; waist-hip ratio: r = 0.24, p = 0.04). The carriers of rare variants IVS1-2G-A (rs373975305); A43T (rs147210663) and IVS3 + 1G-T (rs140621530) showed high TG but not low ApoC-III levels in Asian Indians and Caucasians.

CONCLUSION

These results highlight the challenges of generalizing antisense ApoC-III inhibition for treating atherosclerotic disease in dyslipidemia that may benefit only specific sub-populations. The observed ethnic differences in ApoC-III concentrations and CAD risk factors, emphasize in-depth genetic and metabolomics evaluations on diverse ancestries.

Mass spectrometry imaging revealed alterations of lipid metabolites in multicellular tumor spheroids in response to hydroxychloroquine

Three-dimensional (3D) multicellular tumor spheroids (MCTS) that mimic the complex tumor microenvironment provide a good platform for in vitro study of drug and endogenous metabolites. Hydroxychloroquine (HCQ) has shown anti-tumor activity in a variety of tumor models. However, the effect of the drug on the alteration of lipid metabolism spatial composition and distribution in the MCTS model is not clear. Herein, we utilized matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) in the analysis of A549 lung cancer multicellular spheroids to investigate the in situ spatial distribution of HCQ and its effect on lipid metabolism. We have successfully observed the spatial variations of HCQ in the inner region of the spheroid at different drug-treated time points. The MSI results also demonstrated that HCQ treatment altered the spatial composition of lipids in the inner and outer regions of treated spheroids. Furthermore, the lipidomic results showed that the identified phosphatidylcholines (PC), lysophosphatidylcholines (LPC), phosphatidylethanolamines (PE), lysophosphatidylethanolamines (LPE), phosphatidylinositols (PI), ceramides (Cer), glucosylceramides (CerG), and diglycerides (DG) were significantly up-regulated, and phosphatidylglycerol (PG) and triglycerides (TG) were remarkable down-regulated. MSI method combined with LC-MS/MS profiling of endogenous metabolites can obtain more detailed information about how spheroids respond to drug and spatial distribution information, thus fostering a better understanding of the relationship between drug-altered lipid metabolism and cancer microenvironment.

GC-MS metabolomics reveals dysregulated lipid metabolic pathways and metabolites in diabetic testicular toxicity: Therapeutic potentials of raffia palm (Raphia hookeri G. Mann & H. Wendl) wine

ETHNOPHARMACOLOGICAL RELEVANCE

Raffia palm (Raphia hookeri G. Mann & H. Wendl) wine (RPW) is a natural beverage obtained from the R. hookeri consumed for refreshment and medicinal purposes. For medicinal purposes, it is used singly or as macerating agent for other medicinal plants for the treatment of several diseases.

AIM

This study investigates the effect of Raffia palm wine on dysregulated lipid metabolic pathways in testicular tissues of type 2 diabetic (T2D) rats.

METHODS

Raffia palm wine (150 and 300 mg/kg bodyweight) was administered to two T2D groups respectively, another T2D group was not administered treatment and served as negative control, while metformin served as the standard drug. After 6 weeks of treatment, the rats were sacrificed, and the testes collected. After weighing, the organs were homogenized in 20% methanol/ethanol and centrifuged at 20,000 g to extract the lipid metabolites.

RESULTS

GC-MS analysis of the supernatants revealed an alteration of the metabolites on induction of T2D, with concomitant generation of 10 metabolites. Raffia palm wine inhibited the T2D-generated metabolites while replenishing cholesterol and squalene levels, with concomitant generation of 7 and 8 metabolites for low and high dose treatment respectively. Pathway enrichment analysis of the metabolites revealed a decreased level of steroid biosynthesis and increased level of fatty acid biosynthesis. Raffia palm wine inactivated glycerolipid, fatty acid, and arachidonic acid metabolisms, fatty acid biosynthesis and fatty acid elongation in mitochondria pathways, and activated pathways for plasmalogen synthesis, mitochondrial beta-oxidation of long chain saturated fatty acids.

CONCLUSION

The replenishment and generation of these metabolites and additional ones as well as activation of pathways involved in energy generation, phospholipids, antioxidant activity, steroidogenesis and spermatogenesis suggest a therapeutic effect of Raffia palm wine against hyperglycemic-induced testicular dysfunction.

Physiological markers suggest energetic and nutritional adjustments in male sharks linked to reproduction

Energetic condition is one of the most important factors that influence fitness and reproductive performance in vertebrates. Yet, we lack evidence on how energetic states change in response to reproduction in large marine vertebrates. In the present study, we used a non-lethal approach to assess relationships among reproductive stage, circulating steroid hormones (testosterone and relative corticosteroid levels), plasma fatty acids, and the ketone body β-hydroxybutyrate in male sharks of two species with divergent ecologies, the benthic nurse shark (Ginglymostoma cirratum) and the epipelagic blacktip shark (Carcharhinus limbatus). We found higher relative corticosteroid levels in adult nurse sharks during the pre-mating period and in blacktip sharks during the mating period. Higher levels of β-hydroxybutyrate were found in adult nurse sharks during the mating period, but concentrations of this ketone body did not significantly vary across reproductive stages in blacktip sharks. We also detected reduced percentages of essential fatty acids during the mating period of both nurse and blacktip sharks. Taken together, our findings suggest that nurse and blacktip sharks differ in their energetic strategy to support reproduction, however, they likely rely on physiologically important fatty acids during mating, to support spermatogenesis.

Screening of lipid metabolism biomarkers in patients with coronary heart disease via ultra-performance liquid chromatography-high resolution mass spectrometry

Coronary heart disease (CHD) has a high mortality worldwide. This study aimed to screen lipid metabolism biomarkers in patients with coronary heart disease via ultra-performance liquid chromatography-high resolution mass spectrometry. Extraction and reconstitution solvents, liquid chromatographic and mass spectrometry conditions were optimized to detect more plasma lipid metabolites. In this study, the chromatographic and mass spectra characteristics of lipid metabolites were summarized. A total of 316 lipid metabolites were annotated via diagnostic fragment ion filtration, nitrogen rule filtration, and neutral loss filtration. Glycerophospholipid metabolism and sphingolipid metabolism were revealed as the main lipid disorders of CHD. This study provides a novel insight for high-throughput detection of lipid metabolites in plasma and provides a further understanding of the occurrence of CHD, which can provide valuable suggestions for the prevention of CHD.

Association of cardiac autonomic dysfunction with higher levels of plasma lipid metabolites in recent-onset type 2 diabetes

AIMS/HYPOTHESIS

Emerging evidence suggests that in addition to hyperglycaemia, dyslipidaemia could represent a contributing pathogenetic factor to diabetic neuropathy, while obesity and insulin resistance play a role in the development of diabetic cardiac autonomic neuropathy (CAN) characterised by reduced heart rate variability (HRV), particularly in type 2 diabetes. We hypothesised that distinct lipid metabolites are associated with diminished HRV in recent-onset type 2 diabetes rather than type 1 diabetes.

METHODS

We analysed 127 plasma lipid metabolites (11 acylcarnitines, 39 NEFA, 12 sphingomyelins (SMs), 56 phosphatidylcholines and nine lysophosphatidylcholines) using MS in participants from the German Diabetes Study baseline cohort recently diagnosed with type 1 (n = 100) and type 2 diabetes (n = 206). Four time-domain HRV indices (number of normal-to-normal (NN) intervals >50 ms divided by the number of all NN intervals [pNN50]; root mean square of successive differences [RMSSD]; SD of NN intervals [SDNN]; and SD of differences between adjacent NN intervals) and three frequency-domain HRV indices (very-low-frequency [VLF], low-frequency [LF] and high-frequency [HF] power spectrum) were computed from NN intervals recorded during a 3 h hyperinsulinaemic-euglycaemic clamp at baseline and in subsets of participants with type 1 (n = 60) and type 2 diabetes (n = 95) after 5 years.

RESULTS

In participants with type 2 diabetes, after Bonferroni correction and rigorous adjustment, SDNN was inversely associated with higher levels of diacyl-phosphatidylcholine (PCaa) C32:0, PCaa C34:1, acyl-alkyl-phosphatidylcholine (PCae) C36:0, SM C16:0 and SM C16:1. SD of differences between NN intervals was inversely associated with PCaa C32:0, PCaa C34:1, PCaa C34:2, PCae C36:0 and SM C16:1, and RMSSD with PCae C36:0. For VLF power, inverse associations were found with PCaa C30:0, PCaa C32:0, PCaa C32:1, PCaa C34:2 and SM C16:1, and for LF power inverse associations were found with PCaa C32:0 and SM C16:1 (r = -0.242 to r = -0.349; p ≤ 0.0005 for all correlations). In contrast, no associations of lipid metabolites with measures of cardiac autonomic function were noted in participants recently diagnosed with type 1 diabetes. After 5 years, HRV declined due to ageing rather than diabetes, whereby prediction analyses for lipid metabolites were hampered.

CONCLUSIONS/INTERPRETATION

Higher plasma levels of specific lipid metabolites are closely linked to cardiac autonomic dysfunction in recent-onset type 2 diabetes but not type 1 diabetes, suggesting a role for perturbed lipid metabolism in the early development of CAN in type 2 diabetes. Graphical abstract.

Adipocytes in the Tumour Microenvironment

Adipose tissue contribution to body mass ranges from 6% in male athletes to over 25% in obese men and over 30% in obese women. Crosstalk between adipocytes and cancer cells that exist in close proximity can lead to changes in the function and phenotype of both cell types. These interactions actively alter the tumour microenvironment (TME). Obesity is one of the major risk factors for multiple types of cancer, including breast cancer. In obesity, the increase in both size and number of adipocytes leads to instability of the TME, as well as increased hypoxia within the TME, which further enhances tumour invasion and metastasis. In this chapter, we will discuss the diverse aspects of adipocytes and adipocyte-derived factors that affect the TME as well as tumour progression and metastasis. In addition, we discuss how obesity affects the TME. We focus primarily on breast cancer but discuss what is known in other cancer types when relevant. We finish by discussing the studies needed to further understand these complex interactions.

Activation of NLRP3 Inflammasome Promotes Foam Cell Formation in Vascular Smooth Muscle Cells and Atherogenesis Via HMGB1

Background

This study aimed at investigating whether NLRP3 (the Nod like receptor family, pyrin domain‐containing 3 protein) inflammasome activation induced HMGB1 (high mobility group box‐1 protein) secretion and foam cell formation in human vascular smooth muscle cells (VSMCs) and atherosclerosis in ApoE^−/− mice.

Methods and Results

VSMCs or ApoE^−/− mice were treated with lipopolysaccharides (LPS) and/or ATP or LPS and high‐fat diet to induce NLRP3 inflammasome activation. HMGB1 distribution and foam cell formation in VSMCs were characterized. Liver X receptor α and ATP‐binding cassette transporter expression were determined. The impact of NLRP3 or receptor for advanced glycation end product silencing, ZYVAD‐FMK (caspase‐1 inhibitor), glycyrrhizin (HMGB1 inhibitor) or receptor for advanced glycation end product antagonist peptide on HMGB1 secretion, foam cell formation, liver X receptor α and ATP‐binding cassette transporter expression was examined. Expression level of HMGB1 in human atherosclerosis obliterans arterial tissues was characterized. Our results found that NLRP3 inflammasome activation promoted foam cell formation and HMGB1 secretion in VSMCs. Extracellular HMGB1 was a key signal molecule in inflammasome activation‐mediated foam cell formation. Furthermore, inflammasome activation‐induced HMGB1 activity and foam cell formation were achieved by receptor for advanced glycation end product/liver X receptor α /ATP‐binding cassette transporter glycyrrhizin. Experiments in vivo found glycyrrhizin significantly attenuated the LPS/high‐fat diet‐induced atherosclerosis and serum HMGB1 levels in mice. Finally, levels of HMGB1 and NLRP3 were increased in tunica media adjacent to intima of atherosclerosis obliteran arteries.

Conclusions

Our results revealed that HMGB1 is a key downstream signal molecule of NLRP3 inflammasome activation and plays an important role in VSMCs foam cell formation and atherogenesis by downregulating liver X receptor α and ATP‐binding cassette transporter expression through receptor for advanced glycation end product.

Circulating inflammation-resolving lipid mediators RvD1 and DHA are decreased in patients with acutely symptomatic carotid disease

BACKGROUND

Efficient biomarkers for early prediction and diagnosis of an acutely symptomatic carotid plaque rupture event are currently lacking, impairing the ability to diagnose and treat patients with an acute plaque rupture events in a timely fashion. Resolvins are endogenous inflammation-resolving lipid mediators that are induced by inflammatory insults. We hypothesized that resolvin and other lipid profiles in sera likely mark the process towards plaque rupture.

METHODS

Circulating lipids associated with plaque rupture events were quantitatively profiled via targeted mediator-lipidomics using ultraperformance liquid chromatography tandem mass spectrometry in patients with acutely symptomatic and asymptomatic carotid disease.

RESULTS

Resolvin D1 (RvD1, 82 ± 11pM vs. 152 ± 17pM, p = 0.001) and docosahexaenoic acid (DHA) (0.052 ± 0.007µM versus 0.076 ± 0.008µM, p = 0.025) levels are decreased in the sera of patients presenting with an acutely symptomatic carotid plaque rupture event (n = 21) compared to patients with asymptomatic (n = 24) high-grade carotid stenosis. Circulating arachidonic acid (AA) levels, however, were higher (0.429 ± 0.046µM versus 0.257 ± 0.035µM, p < 0.01) in acutely symptomatic compared to asymptomatic carotid patients. ROC curve analysis demonstrates that the serum ratio AA:RvD1 (AUC 0.84, sensitivity 0.71, specificity 0.92) and AA:DHA (AUC 0.86, sensitivity 0.90, specificity 0.71) are biomarkers for the risk of atherosclerotic plaque rupture.

CONCLUSIONS

A circulating pro-inflammatory lipid profile, characterized by high AA:RvD1 and AA:DHA, is associated with acutely symptomatic carotid disease and stroke.

A new use for an old index: preoperative high-density lipoprotein predicts recurrence in patients with hepatocellular carcinoma after curative resections

Background

Hepatocellular carcinoma has high incidence and mortality worldwide. Liver is the site of most metabolic biotransformation, which could reflect the status of cells. Most plasma apolipoproteins, endogenous lipids and lipoproteins are synthesized in the liver. Therefore, the effects of lipid metabolites on prognosis of HCC deserved to be explored.

Methods

We prospectively included 58 healthy donors (HD), 50 chronic hepatitis (CH) patients and a training cohort of 189 patients with HCC who underwent curative resections at Zhongshan Hospital from January 2012 to August 2012. We identified the optimal HDL_PO cutoff value at 0.98 mmol/L and used it to stratify patients into low- or high-HDL_PO groups for the entire cohort and four low-recurrent-risk subgroups. We also included an independent validation group of 182 HCC patients to validate this cutoff value. Prognostic values of HDL_PO and other factors were determined by Kaplan–Meier curves and the Cox proportional hazards model.

Results

The low-HDL_PO group had a higher median tumor grade (P = 0.020) and a higher recurrence rate (P = 0.032). Results of multivariate analysis showed that preoperative γ-glutamyl transpeptidase (GGT) and HDL_PO were independent predictors of recurrence. Moreover, the predictive value of HDL_PO was retained in four low-recurrent-risk subgroups. As expected, clinicopathologic characteristics and predictive values were similar in the validation and training cohorts.

Conclusions

HDL_PO is an accessible predictor of HCC recurrence after liver resections that can help identify patients who need more careful monitoring and follow-up care.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-017-0509-3) contains supplementary material, which is available to authorized users.

HL271, a novel chemical compound derived from metformin, differs from metformin in its effects on the circadian clock and metabolism

Metformin is a treatment of choice for patients with type 2 diabetes. Its action involves the phosphorylation of 5'-adenosine monophosphate activated protein kinase (AMPK), leading to inhibition of liver gluconeogenesis. The effects of a novel chemical compound derived from metformin, HL271, on molecular and physiological actions involving AMPK and rhythmically-expressed circadian clock genes were investigated. HL271 potently activated AMPK in a dose-dependent manner, and produced shortening of the circadian period and enhanced degradation of the clock genes PER2 and CRY1. Although the molecular effects of HL271 resembled those of metformin, it produced different physiological effects in mice with diet-induced obesity. HL271 did not elicit glucose-lowering or insulin-sensitizing effects, possibly because of altered regulation of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1. This indicated that, although HL271 acted on circadian clock machinery through a similar molecular mechanism to metformin, it differed in its systemic effect on glucose and lipid metabolite regulations.

Phenotypic flexibility in passerine birds: seasonal variation in fuel storage, mobilization and transport

Winter acclimatization in small birds living in cold climates produces a winter phenotype characterized by upregulation of metabolic rates to meet enhanced thermoregulatory demands. We measured several key aspects of fuel storage, mobilization and transport in summer and winter to determine whether black-capped chickadees (Poecile atricapillus), white-breasted nuthatches (Sitta carolinensis), and house sparrows (Passer domesticus) seasonally modulate these attributes to meet enhanced winter thermoregulatory demands. In addition, we exposed birds to thermoneutral (control) and severe cold exposure treatments to determine whether acute cold exposure influenced fuel storage, mobilization or transport. Carcass lipid mass and pectoralis intramuscular lipid did not vary significantly between seasons or temperature treatments for any of the study species. Muscle glycogen varied significantly seasonally only for chickadee supracoracoideus and leg muscles, and did not vary among warm or cold treatments for any species. Pectoralis fatty acid binding protein (FABPc) was significantly elevated in winter for chickadees and nuthatches, but not for sparrows. Plasma metabolites showed little consistent variation in response to season or acute cold exposure. Thus, fuel storage and mobilization do not appear to be major targets of adjustment associated with seasonal metabolic flexibility in these species, but modulation of intracellular lipid transport by FABPc may be an important contributor to seasonal phenotypes in some species of small birds.