Lysophosphatidylcholine—biomarker of Metformin action: studied using UPLC/MS/MS

An UPLC/MS/MS based metabonomic method was developed and applied to the elucidation of biomarker of metformin action. The plasma metabolite profiling in healthy volunteers before and after per os metformin was determined with UPLC/MS/MS and analyzed by using multivariate statistics. Significant difference in endogenous metabolite profiles was revealed before and after administration of metformin. Four biomarkers found were lysophosphatidylcholines (LPCs), and their structures were tentatively identified to be 16:0 LPC, 18:0 LPC, 18:1 LPC and 18:2 LPC according to the molecular ions information and corresponding fragments of product ion scan. Lysophosphatidylcholine in blood may be involved in metformin treatment. Copyright © 2009 John Wiley & Sons, Ltd.     

儿茶素对溶血卵磷脂胆碱所致细胞损伤的保护作用

作者以体外培养的小牛主动脉内皮细胞为材料,研究了溶血卵磷脂胆碱（LPC）和氧自由基（OFR）对血管内皮细胞（VEC）的损伤,及儿茶素对VEC的保护。结果显示：当VEC与LPC（6ug/ml）或黄嘌呤／黄嘌呤氧化酶（X／XO）（10umol/L 200umol/L）共孵育24小时时,表现为细胞内乳酸脱氢酶（LDH）泄漏量增多,细胞内过氧化脂质丙二醛（MDA）含量升高,细胞生长减缓,存活率下降;当加入不同浓度的儿茶素后则可明显抑制LDH的泄量,降低MDA含量,细胞生长正常,存活率提高。表明LPC与X／XO对VEC有损伤作用,而儿茶素则能通过抗氧化途径抵抗LPC与X／XO至VEC的损伤。     

Characterization of alkylacyl,alk-1-enylacyl and lyso subclasses of glycerophosphocholine by tandem quadrupole mass spectrometry with electrospray ionization

Positive ion tandem quadrupole mass spectrometric methods for structural characterization of the subclasses of sn-glycero-3-phosphocholine (PC), including alkylacyl- and alk-1-enylacylphosphocholine and lysophosphatidylcholine (LPC), are described. Following collisionally activated dissociation, the [M + Li](+) ions generated by electrospray ionization yield abundant informative fragment ions that permit structural determination, and distinction of regioisomers among lysophosphatidylcholine can be easily achieved. In contrast, structurally informative ions arising from [M + H](+) or [M + Na](+) ions are less prominent. The most abundant ion observed in the product-ion spectra of the [M + Li](+) ions of plasmenyl- and plasmanyl-PC and of LPC arises from loss of N(CH(3))(3) ([M + Li - 59](+)). This feature permits their distinction from a product-ion spectrum arising from a diacylphosphatidylcholine, in which the [M + Li - 183](+) ion reflecting loss of phosphocholine is the most prominent. Examples for identification of various subclasses of PC in biological extracts by tandem mass spectrometry applying various constant neutral loss scannings are also shown.     

A new approach to the synthesis of lysophosphatidylcholines and related derivatives

A new stereospecific synthesis of lysophosphatidylcholines is reported. The sequence relies on orthogonal protection of hydroxyl groups derived from glyceric acid, using fluorenylmethylcarbonate versus tetrahydropyranyl ether functions, that allow regiospecific introduction of substituents to obtain the target phospholipid compound.     

Phospholipidomic identification of potential plasma biomarkers associated with type 2 diabetes mellitus and diabetic nephropathy

Type 2 diabetes mellitus (T2DM) and its attendant complications, such as diabetic nephropathy (DN), impose a significant societal and economic burden. The investigation of discovering potential biomarkers for T2DM and DN will facilitate the prediction and prevention of diabetes. Phospholipids (PLs) and their metabolisms are closely allied to nosogenesis and aggravation of T2DM and DN. The aim of this study is to characterize the human plasma phospholipids in T2DM and DN to identify potential biomarkers of T2DM and DN. Normal phase liquid chromatography coupled with time of flight mass spectrometry (NPLC-TOF/MS) was applied to the plasma phospholipids metabolic profiling of T2DM and DN. The plasma samples from control (n = 30), T2DM subjects (n = 30), and DN subjects (n = 52) were collected and analyzed. The significant difference in metabolic profiling was observed between healthy control group and DM group as well as between control group and DN group by the help of partial least squares discriminant analysis (PLS-DA). PLS-DA and one-way analysis of variance (ANOVA) were successfully used to screen out potential biomarkers from complex mass spectrometry data. The identification of molecular components of potential biomarkers was performed on Ion trap-MS/MS. An external standard method was applied to quantitative analysis of potential biomarkers. As a result, 18 compounds in 7 PL classes with significant regulation in patients compared with healthy controls were regarded as potential biomarkers for T2DM or DN. Among them, 3 DM-specific biomarkers, 8 DN-specific biomarkers and 7 common biomarkers to DM and DN were identified. Ultimately, 2 novel biomarkers, i.e., PI C18:0/22:6 and SM dC18:0/20:2, can be used to discriminate healthy individuals, T2DM cases and DN cases from each other group.     

LY333531对高糖高脂下系膜细胞分泌细胞外基质的影响

探讨PKCβ抑制剂(LY333531)对高糖高脂环境下系膜细胞分泌细胞外基质(ECM)的影响,单独培养人肾小球系膜细胞,实验分为对照组、LY333531组、高糖高脂组、高糖高脂+LY333531组.首先采用qRTPCR检测PKCβI的表达,然后通过ELISA法检测细胞上清液Col IV、Fn的含量.结果显示,高糖高脂组相较于对照组,PKCβI mRNA的表达水平明显增加(P0.05),LY333531可以明显抑制PKCβI的表达(P0.05);高糖高脂组相较于对照组,细胞上清液Col IV、Fn含量明显增加(P0.05),而这种作用可被LY333531所抑制(P0.05).表明高糖高脂可通过促进系膜细胞PKCβI表达从而诱导ECM的分泌,增加肾纤维化发生的风险,而LY333531可明显抑制这种作用.