The analysis of nitrated polycyllc aromatic hydrocarbons (nltro-PAH) In diesel particulate extracts using a combination of high-performance liquid chromatography, gas chromatography/mass spectrometry, hlgh-resolutlon mass spectrometry, and mass spectrometry/mass spectrometry (MS/MS) techniques Is described. Triple stage quadrupole (TSQ)-MSZMS operated In the constant neutral loss mode Is described for the rapid qualitative screening of nltro-PAH Isomer groups In solvent extracts of diesel particulates. Twenty such Isomer groups of nltro-PAH derivatives were found, many of these groups containing a large number of possible compounds.Mass analyzed Ion kinetic energy spectrometry (MIKES)-MS/MS was found to be much less selective than the TSQ-MS/MS for the analysis of nltro-PAH In unfractionated diesel extracts. HPLC prefractlonatlon was required to remove Interferences In the MIKES analysis. Fused silica capillary GC/MS using on-column Injection was found to be necessary for Indentlfylng specific nltro-PAH Isomers and minimizing decomposition. The highly mutagenic 1-nltropyrene (1-NP) was the only compound found In the nltro(pyrenes and fluoranthenes) Isomer group. The MIKES and TSQ techniques gave comparable results for the quantitation of 1-NP.Organic solvent extracts of diesel exhaust particulates exhibit direct-acting (i.e., activation by mammalian tissue homogenate is not required) mutagenicity (1-5) using the Ames assay (6). High-performance liquid chromatography (HPLC) (1,2,4,5), thin-layer chromatography (TLC) (7,8), and liquid chromatography (9) have been used to fractionate diesel particulate extracts for subsequent mutagenicity testing.

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BackgroundLipid intermediates produced during triacylglycerols (TAGs) synthesis and lipolysis in adipocytes interfere with the intracellular insulin signaling pathway and development of insulin resistance. This study aims to compare TAG species and their fatty acid composition in adipose tissues from insulin sensitive (IS), insulin resistant (IR) and type 2 diabetes mellitus (T2DM) obese individuals.MethodsHuman subcutaneous and omental adipose tissue biopsies were obtained from 64 clinically characterized obese individuals during weight reduction surgery. TAGs were extracted from the adipose tissues using the Bligh and Dyer method, then were subjected to non-aqueous reverse phase ultra-high performance liquid chromatography and full scan mass spectrometry acquisition and data dependent MS/MS on LTQ dual cell linear ion trap. TAGs and their fatty acid contents were identified and compared between IS, IR and T2DM individuals and their levels were correlated with metabolic traits of participants and the adipogenic potential of preadipocyte cultures established from their adipose tissues.ResultsData revealed 76 unique TAG species in adipose tissues identified based on their exact mass. Analysis of TAG levels revealed a number of TAGs that were significantly altered with disease progression including C46:4, C48:5, C48:4, C38:1, C50:3, C40:2, C56:3, C56:4, C56:7 and C58:7. Enrichment analysis revealed C12:0 fatty acid to be associated with TAGs least abundant in T2DM whereas C18:3 was found in both depleted and enriched TAGs in T2DM. Significant correlations of various adipose tissue-derived TAG species and metabolic traits were observed, including age and body mass index, systemic total cholesterol, TAGs, and interleukin-6 in addition to adipogenic potential of preadipocytes derived from the same adipose tissues.ConclusionPilot data suggest that adipose tissues from obese IR and T2DM individuals exhibit TAG-specific signatures that may contribute to their increased risk compared to their IS counterparts. Future experiments are warranted to investigate the functional relevance of these specific lipidomic profiles.Electronic supplementary materialThe online version of this article (10.1186/s12967-018-1548-x) contains supplementary material, which is available to authorized users.

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