Plasma phospholipid transfer protein activity is independently determined by obesity and insulin resistance in non-diabetic subjects

Sevoflurane Exposure of Clinical Doses in Pregnant Rats Induces Vcan Changes without Significant Neural Apoptosis in the Offspring

Background and Objectives: Sevoflurane is a commonly used inhalational anaesthetic in clinics. Prolonged exposure to sevoflurane can induce significant changes in lipid metabolism and neuronal damage in the developing brain. However, the effect of exposure of pregnant rats to clinical doses of sevoflurane remains unclear. Materials and Methods: Twenty-eight pregnant rats were randomly and equally divided into sevoflurane exposure (S) group, control (C) and a blank group at gestational day (G) 18; Rats in S group received 2% sevoflurane with 98% oxygen for 6 h in an anesthetizing chamber, while C group received 100% oxygen at an identical flow rate for 6 h in an identical chamber. Partial least squares discriminant analysis (PLS-DA), ultra performance liquid chromatography/time-of-flight mass spectrometry(UPLC/TOF-MS) and MetaboAnalyst were used to analysis acquire metabolomics profiles, and immunohistochemical changes of neuronalapoptosis in hippocampus and cortex of neonatal rats were also analyzed. Results: This study aimed to explore lipidomics and transcriptomics changes related to 2% sevoflurane exposure for 6 h in the developing brains of newborn offspring rats. Ultra-performance liquid chromatography/time-of-flight mass spectrometry (UPLC/TOF-MS) and RNA sequencing (RNA-seq) analyses were used to acquire metabolomics and transcriptomics profiles. We used RNA-seq to analyse the expression of the coding and non-coding transcripts in neural cells of the cerebral cortex. No significant differences in arterial oxygen tension (PaO₂), arterial carbon dioxide tension (PaCO₂), or arterial blood gas were found between the groups. The relative standard deviation (RSD) of retention times was <1.53%, and the RSDs of peak areas ranged from 2.13% to 8.51%. Base peak chromatogram (BPC) profiles showed no differences between the groups. We evaluated the partial least square-discriminant analysis (PLS-DA) model. In negative ion mode, R2X was over 70%, R2Y was over 93%, and Q2 (cum) was over 80%. Cell apoptosis was not remarkably enhanced by TUNEL and haematoxylin and eosin (HE) staining in the sevoflurane-exposed group compared to the control group (p > 0.05). Glycerophospholipid (GP) and sphingolipid metabolism disturbances might adversely influence neurodevelopment in offspring. The expression of mRNAs (Vcan gene, related to neuronal development, function and repair) of the sevoflurane group was significantly increased in the differential genes by qRT-PCR verification. Conclusions: GP and sphingolipid metabolism homeostasis may be potential therapeutic approaches against inhalational anaesthetic-induced neurodegenerative disorders. Meanwhile, sevoflurane-induced Vcan changes indicated some lipidomic and transcriptomic changes, even if neural cell apoptosis was not significantly changed in the usual clinical dose of sevoflurane exposure.

New therapeutic horizons for plasma phospholipid transfer protein (PLTP): Targeting endotoxemia, infection and sepsis

Phospholipid Transfer Protein (PLTP) transfers amphiphilic lipids between circulating lipoproteins and between lipoproteins, cells and tissues. Indeed, PLTP is a major determinant of the plasma levels, turnover and functionality of the main lipoprotein classes: very low-density lipoproteins (VLDL), low-density lipoproteins (LDL) and high-density lipoproteins (HDL). To date, most attention has been focused on the role of PLTP in the context of cardiometabolic diseases, with additional insights in neurodegenerative diseases and immunity. Importantly, beyond its influence on plasma triglyceride and cholesterol transport, PLTP plays a key role in the modulation of the immune response, with immediate relevance to a wide range of inflammatory diseases including bacterial infection and sepsis. Indeed, emerging evidence supports the role of PLTP, in the context of its association with lipoproteins, in the neutralization and clearance of bacterial lipopolysaccharides (LPS) or endotoxins. LPS are amphipathic molecules originating from Gram-negative bacteria which harbor major pathogen-associated patterns, triggering an innate immune response in the host. Although the early inflammatory reaction constitutes a key step in the anti-microbial defense of the organism, it can lead to a dysregulated inflammatory response and to hemodynamic disorders, organ failure and eventually death. Moreover, and in addition to endotoxemia and acute inflammation, small amounts of LPS in the circulation can induce chronic, low-grade inflammation with long-term consequences in several metabolic disorders such as atherosclerosis, obesity and diabetes. After an updated overview of the role of PLTP in lipid transfer, lipoprotein metabolism and related diseases, current knowledge of its impact on inflammation, infection and sepsis is critically appraised. Finally, the relevance of PLTP as a new player and novel therapeutic target in the fight against inflammatory diseases is considered.

Outstanding improvement of the advanced lipoprotein profile in subjects with new-onset type 1 diabetes mellitus after achieving optimal glycemic control

AIMS

The impact of glycemic optimization on lipoprotein subfraction parameters in apparently normolipidemic subjects with new-onset type 1 diabetes mellitus (T1D) was examined.

METHODS

We evaluated the serum lipid and advanced lipoprotein profiles in twenty subjects at onset of T1D and twenty non-diabetic controls by laboratory methods and 1H NMR spectroscopy shortly after diabetes diagnosis (baseline), and after achieving optimal glycemic control (HbA1c ≤ 7.0%).

RESULTS

Advanced lipoprotein analysis revealed a significant reduction from baseline in serum concentrations of triglycerides (TG), cholesterol (C), and apolipoprotein (Apo)B-containing lipoproteins of treated subjects (VLDL-TG: -21%, IDL-TG: -30%, LDL-TG: -34%, LDL-TG: -36%, P < 0.05; VLDL-C: -23%, IDL-C: -44%, LDL-C: -16%; p < 0.05). Decreased VLDL and LDL lipids were mainly attributed to concomitant reductions in the concentration of medium-sized VLDL (-36%) and medium-sized LDL (-31%) and, to a lesser extent, to large-sized LDL (-14%). Notably, proatherogenic IDL characteristics and related surrogates of atherogenicity were resolved upon achievement of optimal glycemic status. Moreover, the concentration of HDL-TG was also reduced (-18%) at follow-up.

CONCLUSIONS

Our data showed that the achievement of optimal glycemic control after T1D onset corrected hidden derangements in ApoB-containing lipoproteins (particularly IDL) and HDL-TG that are related to higher cardiovascular risk in poorly controlled T1D.

A metabolomics research based on UHPLC-ESI-Q-TOF-MS coupled with metabolic pathway analysis: Treatment effects of stir-frying Xanthii Fructus on allergic rhinitis in mice model

Xanthii Fructus (XF), a well-known herb in traditional Chinese medicine, has been frequently used for the treatment of allergic rhinitis in the clinic. Its therapeutic metabolic mechanism, however, remains undetermined. In this work, a metabolomics research coupled with metabolic pathway analysis has been employed to screen out the potential mechanism in its effects on allergic rhinitis. Specifically, mouse serum samples containing XF were analyzed based on ultra-high performance liquid chromatography equipped with electrospray ionization quadruple time-of-flight mass spectrometry detection (UHPLC-ESI-Q-TOF-MS) in both positive and negative polarity. In addition, the raw data gained from UHPLC-ESI-Q-TOF-MS were processed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) in order to discover remarkable metabolites. Twenty-seven potential biomarkers in mouse serum were filtered from free databases like HMDB. Interestingly, this study filtered the potential metabolic pathways including glycerophospholipid metabolism and branch-chain amino acid metabolism. We hope that this paper will provide a feasible strategy for revealing the therapeutic mechanism of XF in allergic rhinitis mice model.

Plasma lecithin:cholesterol acyltransferase and phospholipid transfer protein activity independently associate with nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent condition which contributes to atherogenic apolipoprotein B dyslipoproteinemias. Lecithin:cholesterol acyltransferase (LCAT) and phospholipid transfer protein (PLTP) are both synthesized by the liver and are important in lipid metabolism. Here, we interrogated the impact of NAFLD on plasma LCAT and PLTP activities.

METHODS

Plasma LCAT activity (exogenous substrate assay) and PLTP activity (phospholipid vesicles-HDL assay) were determined in 348 subjects (279 men; 81 subjects with type 2 diabetes (T2DM); 123 with metabolic syndrome (MetS)). A Fatty Liver Index (FLI) ≥60 was used as a proxy of NAFLD. Insulin resistance was determined by homoeostasis model assessment (HOMA-IR).

RESULTS

A total of 147 participants had an FLI ≥60 coinciding with T2DM and MetS (P < 0.001 for each). Plasma LCAT activity and PLTP activity were on average 12% and 5% higher, respectively, in subjects with an FLI ≥ 60 (P < 0.001 for each). In age- and sex-adjusted partial linear regression analysis, LCAT activity and PLTP activity were positively related to various obesity measures and HOMA-IR (P < 0.001 for each). In multivariable linear regression analyses adjusted for age and sex, LCAT activity was associated with an FLI ≥ 60 independent of T2DM and MetS, the waist/hip ratio, or HOMA-IR (β = 0.307 to 0.366, P < 0001 for all models). PLTP activity was also associated with an FLI ≥ 60 independent of these variables (β = 0.151 to 0223, P = 0.013 to 0.001).

CONCLUSION

NAFLD, as inferred from an FLI≥60, confers higher plasma LCAT and to a lesser extent PLTP activity, even when taking account of T2DM, MetS, central obesity and insulin resistance.

Comparison of frequency of insulin resistance in patients with chronic obstructive pulmonary disease with normal controls

OBJECTIVE

To compare mean homeostatic model assessment of insulin resistance (HOMA-IR) in patients with and without chronic obstructive pulmonary disease (COPD).

METHODS

A Case control analytic study was conducted in medical outpatient department of Medial Unit-II of Dow University of Health Sciences from April 2013 to September 2013. All patients with the diagnosis of COPD were included as cases. Controls were age match healthy individuals with minor illnesses. Age, weight, height and forced expiratory volume in one second to forced vital capacity (FEV1/FVC) ratio were documented. Fasting blood glucose and fasting insulin levels were done. Body mass index (BMI) and IR was calculated using the formulas. HOMA-IR was compared between cases and controls.

RESULTS

Forty COPD patients were compared with thirty five age match controls. HOMA-IR was found to be higher in cases as compared to controls (2.85 v/s 2.00) with a p value <0.000.

CONCLUSION

COPD is one of the chronic debilitating diseases in our region with various extra-pulmonary complications. We found IR to be present higher in COPD patients compared with healthy controls. Evaluating the pulmonary function as well as systemic metabolic parameters, may contribute to minimizing mortality and morbidity.

Rapid identification of erythrocyte phospholipids in Sprague-Dawley rats by ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

A rapid, sensitive, and reliable approach for analyzing five kinds of erythrocyte phospholipids in Sprague-Dawley rats was provided by ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry with MassLynx(TM) MassFragment. Improving conventional high performance liquid chromatography techniques, ultra high performance liquid chromatography integrated with quadrupole time-of-flight tandem mass spectrometry offers high sensitivity and increased analytical speed by using columns packed with sub-2 μm particles (1.7 μm), which allows a faster separation to be achieved. Through this method, 83 phospholipids were tentatively characterized based on their mass spectra and tandem mass spectra, as well as by matching the in-house formula database within a mass error of 5 ppm, including 40 phosphatidylcholines, 24 phosphatidyl ethanolamines, three phosphatidylinositols, six phosphatidylserines, and ten sphingomyelins. Our present results proved that the established method could be used to qualitatively analyze complex erythrocyte phospholipids in Sprague-Dawley rats and provide a useful data base for pharmacology and phospholipidomics to seek potential biomarkers of disease prediction.

HDL size is more accurate than HDL cholesterol to predict carotid subclinical atherosclerosis in individuals classified as low cardiovascular risk

Background

Misclassification of patients as low cardiovascular risk (LCR) remains a major concern and challenges the efficacy of traditional risk markers. Due to its strong association with cholesterol acceptor capacity, high-density lipoprotein (HDL) size has been appointed as a potential risk marker. Hence, we investigate whether HDL size improves the predictive value of HDL-cholesterol in the identification of carotid atherosclerotic burden in individuals stratified to be at LCR.

Methods and Findings

284 individuals (40–75 years) classified as LCR by the current US guidelines were selected in a three-step procedure from primary care centers of the cities of Campinas and Americana, SP, Brazil. Apolipoprotein B-containing lipoproteins were precipitated by polyethylene glycol and HDL size was measured by dynamic light scattering (DLS) technique. Participants were classified in tertiles of HDL size (<7.57; 7.57–8.22; >8.22 nm). Carotid intima-media thickness (cIMT) <0.90 mm (80^th percentile) was determined by high resolution ultrasonography and multivariate ordinal regression models were used to assess the association between cIMT across HDL size and levels of lipid parameters. HDL-cholesterol was not associated with cIMT. In contrast, HDL size >8.22 nm was independently associated with low cIMT in either unadjusted and adjusted models for age, gender and Homeostasis Model Assessment 2 index for insulin sensitivity, ethnicity and body mass index (Odds ratio 0.23; 95% confidence interval 0.07–0.74, p = 0.013).

Conclusion

The mean HDL size estimated with DLS constitutes a better predictor for subclinical carotid atherosclerosis than the conventional measurements of plasma HDL-cholesterol in individuals classified as LCR.

Metabolism of plasma cholesterol and lipoprotein parameters are related to a higher degree of insulin sensitivity in high HDL-C healthy normal weight subjects

Background

We have searched if plasma high density lipoprotein-cholesterol (HDL-C) concentration interferes simultaneously with whole-body cholesterol metabolism and insulin sensitivity in normal weight healthy adult subjects.

Methods

We have measured the activities of several plasma components that are critically influenced by insulin and that control lipoprotein metabolism in subjects with low and high HDL-C concentrations. These parameters included cholesteryl ester transfer protein (CETP), phospholipid transfer protein (PLTP), lecithin cholesterol acyl transferase (LCAT), post-heparin lipoprotein lipase (LPL), hepatic lipase (HL), pre-beta-₁HDL, and plasma sterol markers of cholesterol synthesis and intestinal absorption.

Results

In the high-HDL-C group, we found lower plasma concentrations of triglycerides, alanine aminotransferase, insulin, HOMA-IR index, activities of LCAT and HL compared with the low HDL-C group; additionally, we found higher activity of LPL and pre-beta-₁HDL concentration in the high-HDL-C group. There were no differences in the plasma CETP and PLTP activities.

Conclusions

These findings indicate that in healthy hyperalphalipoproteinemia subjects, several parameters that control the metabolism of plasma cholesterol and lipoproteins are related to a higher degree of insulin sensitivity.

Quantitative genomics of 30 complex phenotypes in Wagyu x Angus F₁ progeny

In the present study, a total of 91 genes involved in various pathways were investigated for their associations with six carcass traits and twenty-four fatty acid composition phenotypes in a Wagyu×Angus reference population, including 43 Wagyu bulls and their potential 791 F₁ progeny. Of the 182 SNPs evaluated, 102 SNPs that were in Hardy-Weinberg equilibrium with minor allele frequencies (MAF>0.15) were selected for parentage assignment and association studies with these quantitative traits. The parentage assignment revealed that 40 of 43 Wagyu sires produced over 96.71% of the calves in the population. Linkage disequilibrium analysis identified 75 of 102 SNPs derived from 54 genes as tagged SNPs. After Bonferroni correction, single-marker analysis revealed a total of 113 significant associations between 44 genes and 29 phenotypes (adjusted P<0.05). Multiple-marker analysis confirmed single-gene associations for 10 traits, but revealed two-gene networks for 9 traits and three-gene networks for 8 traits. Particularly, we observed that TNF (tumor necrosis factor) gene is significantly associated with both beef marbling score (P=0.0016) and palmitic acid (C16:0) (P=0.0043), RCAN1 (regulator of calcineurin 1) with rib-eye area (P=0.0103), ASB3 (ankyrin repeat and SOCS box-containing 3) with backfat (P=0.0392), ABCA1 (ATP-binding cassette A1) with both palmitic acid (C16:0) (P=0.0025) and oleic acid (C18:1n9) (P=0.0114), SLC27A1(solute carrier family 27 A1) with oleic acid (C18:1n9) (P=0.0155), CRH (corticotropin releasing hormone) with both linolenic acid (OMEGA-3) (P=0.0200) and OMEGA 6:3 RATIO (P=0.0054), SLC27A2 (solute carrier family 27 A2) with both linoleic acid (OMEGA-6) (P=0.0121) and FAT (P=0.0333), GNG3 (guanine nucleotide binding protein gamma 3 with desaturase 9 (P=0.0115), and EFEMP1 (EGF containing fibulin-like extracellular matrix protein 1), PLTP (phospholipid transfer protein) and DSEL (dermatan sulfate epimerase-like) with conjugated linoleic acid (P=0.0042-0.0044), respectively, in the Wagyu x Angus F₁ population. In addition, we observed an interesting phenomenon that crossbreeding of different breeds might change gene actions to dominant and overdominant modes, thus explaining the origin of heterosis. The present study confirmed that these important families or pathway-based genes are useful targets for improving meat quality traits and healthful beef products in cattle.

Role of plasma phospholipid transfer protein in lipid and lipoprotein metabolism

The understanding of the physiological and pathophysiological role of PLTP has greatly increased since the discovery of PLTP more than a quarter of century ago. A comprehensive review of PLTP is presented on the following topics: PLTP gene organization and structure; PLTP transfer properties; different forms of PLTP; characteristics of plasma PLTP complexes; relationship of plasma PLTP activity, mass and specific activity with lipoprotein and metabolic factors; role of PLTP in lipoprotein metabolism; PLTP and reverse cholesterol transport; insights from studies of PLTP variants; insights of PLTP from animal studies; PLTP and atherosclerosis; PLTP and signal transduction; PLTP in the brain; and PLTP in human disease. PLTP's central role in lipoprotein metabolism and lipid transport in the vascular compartment has been firmly established. However, more studies are needed to further delineate PLTP's functions in specific tissues, such as the lung, brain and adipose tissue. Furthermore, the specific role that PLTP plays in human diseases, such as atherosclerosis, cancer, or neurodegenerative disease, remains to be clarified. Exciting directions for future research include evaluation of PLTP's physiological relevance in intracellular lipid metabolism and signal transduction, which undoubtedly will advance our knowledge of PLTP functions in health and disease. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).