Derivatization-independent cholesterol analysis in crude lipid extracts by liquid chromatography/mass spectrometry: Applications to a rabbit model for atherosclerosis

Shui, Guanghou; Cheong, Wei Fun; Jappar, Ignasius Aditya; Hoi, Aina; Xue, Yangkui; Fernandis, Aaron Z.; Tan, B. T. G.; Wenk, Markus R.

doi:10.1016/j.chroma.2011.05.011

Cited by 68 publications

(46 citation statements)

References 40 publications

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“…Levels of TAG and wax diester (WDE) were calculated relative to the spiked d5-TAG 48:0 internal standard (CDN Isotopes), while DAG species were quantified using 1, 2-di-O-phytanyl-sn-glycerol (4ME 16:0 diether DG) as an internal standard (Avanti Polar Lipids, Alabaster, AL). Free cholesterol and cholesterol esters were analyzed as described previously with corresponding d6-cholesterol and d6-C 18 cholesterol ester (CDN Isotopes) as internal standards (36). High-resolution mass spectrometry profile analyses of lipid extracts were also carried out using an Accela high-performance liquid chromatography (HPLC) system coupled with an LTQ Orbitrap XL hybrid Fourier transform mass spectrometer (Thermo Fisher Scientific, Waltham, MA) and both reversephase HPLC/MS and normal-phase HPLC/MS approaches as aforementioned.…”

Section: Methodsmentioning

confidence: 99%

Cidea Control of Lipid Storage and Secretion in Mouse and Human Sebaceous Glands

Zhang

Shui

Wang

et al. 2014

Molecular and Cellular Biology

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f Sebaceous glands are skin appendages that secrete sebum onto hair follicles to lubricate the hair and maintain skin homeostasis. In this study, we demonstrated that Cidea is expressed at high levels in lipid-laden mature sebocytes and that Cidea deficiency led to dry hair and hair loss in aged mice. In addition, Cidea-deficient mice had markedly reduced levels of skin surface lipids, including triacylglycerides (TAGs) and wax diesters (WDEs), and these mice were defective in water repulsion and thermoregulation. Furthermore, we observed that Cidea-deficient sebocytes accumulated a large number of smaller-sized lipid droplets (LDs), whereas overexpression of Cidea in human SZ95 sebocytes resulted in increased lipid storage and the accumulation of large LDs. Importantly, Cidea was highly expressed in human sebaceous glands, and its expression levels were positively correlated with human sebum secretion. Our data revealed that Cidea is a crucial regulator of sebaceous gland lipid storage and sebum lipid secretion in mammals and humans.

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Section: Methodsmentioning

confidence: 99%

Cidea Control of Lipid Storage and Secretion in Mouse and Human Sebaceous Glands

Zhang

Shui

Wang

et al. 2014

Molecular and Cellular Biology

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“…As we had previously shown that HPLC/APCI/ MS allows for a wide dynamic linearity range in measuring the levels of CEs in plasma samples due to less ion suppression compared with the ESI mode ( 27 ), the absolute amount of total CEs obtained in APCI/MS/MS was used to correct results obtained in the ESI/MS/MS analysis of individual CE species.…”

Section: Atmospheric Pressure Chemical Ionization Free Chos and Cesmentioning

confidence: 99%

“…were further analyzed using HPLC/atmospheric pressure chemical ionization (APCI)/MS/MS as previously described with corresponding d6-Cho and d6-C18 CE (CDN Isotopes) as internal standards ( 27 ). As we had previously shown that HPLC/APCI/ MS allows for a wide dynamic linearity range in measuring the levels of CEs in plasma samples due to less ion suppression compared with the ESI mode ( 27 ), the absolute amount of total CEs obtained in APCI/MS/MS was used to correct results obtained in the ESI/MS/MS analysis of individual CE species.…”

Section: Atmospheric Pressure Chemical Ionization Free Chos and Cesmentioning

confidence: 99%

Extensive characterization of human tear fluid collected using different techniques unravels the presence of novel lipid amphiphiles

Lam

Tong

Duan

et al. 2014

Journal of Lipid Research

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of the ocular surface. Tears hydrate and lubricate the mucous membranes constituting the ocular surface, supply nourishment to the avascular corneal epithelium, and provide a smooth optical surface essential for visual acuity. The drainage of tears via the lacrimal puncta fl ushes contaminants and irritants out of the eye, thereby functioning as a fi rst line of defense for the anterior eye against invading pathogens ( 1, 2 ). The typical volume of tears in normal eyes ranges from 3.4 to 10.7 l per eye ( 3 ). Despite its small volume, tears represent a biological fl uid of immense complexities with a wide array of proteins/peptides, electrolytes, lipids, and small molecule metabolites contributed by distinct sources ( 1 ). The precise balance of these various metabolites is crucial in ensuring proper physiological function and maintaining biophysical integrity of the precorneal tear fi lm. Perturbations in this delicate equilibrium may be manifested in various ocular conditions such as dry eye syndrome (DES) and blepharitis ( 1,4,5 ).Recent decades have witnessed tremendous progress in the systematic profi ling of proteins as well as small molecule metabolites present in tears ( 1, 6-9 ). Furthermore, with technological advancements in MS and nuclear magnetic Abstract The tear fi lm covers the anterior eye and the precise balance of its various constituting components is critical for maintaining ocular health. The composition of the tear fi lm amphiphilic lipid sublayer, in particular, has largely remained a matter of contention due to the limiting concentrations of these lipid amphiphiles in tears that render their detection and accurate quantitation tedious. Using systematic and sensitive lipidomic approaches, we validated dif ferent tear collection techniques and report the most comprehensive human tear lipidome to date; comprising more than 600 lipid species from 17 major lipid classes. The tear fl uid covers the anterior surface of the cornea and serves critical functions in maintaining the homeostasis

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“…In these experiments, pooled control human plasma was spiked with d7-4βHC at concentrations of 18,22,25,30,35,50,125, and 250 ng/mL (N = 8 at each concentration).…”

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confidence: 99%

Quantification of 4-Beta-Hydroxycholesterol in Human Plasma Using Automated Sample Preparation and LC-ESI-MS/MS Analysis

Goodenough

Onorato

Ouyang

et al. 2011

Chem. Res. Toxicol.

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It has recently been proposed that plasma levels of 4β-hydroxycholesterol (4βHC) may be indicative of cytochrome P450 3A4 (P450 3A) activity and therefore could be used to probe for P450 3A-mediated drug-drug interactions. With this in mind, we describe a highly sensitive and precise liquid chromatography-electrospray ionization-tandem mass spectrometry method for the measurement of 4βHC in human plasma with a lower limit of quantification established at 2 ng/mL using 50 μL of plasma. The entire sample preparation scheme including saponification and derivatization of 4βHC to the corresponding dipicolinyl ester (DPE) was completed in less than 8 h using an automated sample preparation scheme enabling higher-throughput capabilities. Chromatographic resolution of 4βHC from 4α-hydroxycholesterol and other endogenous isobaric species was achieved in 11-min using an isocratic gradient on a C18 column. Because of endogenous concentrations of 4βHC in plasma, a stable isotope labeled (SIL) analogue, d7-4βHC, was used as a surrogate analyte and measured in the standard curve and quality control samples prepared in plasma. A second SIL analogue, d4-4βHC, was used as the internal standard. The intraday and interday accuracy for the assay was within 6% of nominal concentrations, and the precision for these measurements was less than 5% relative standard deviation. Rigorous stability assessments demonstrated adequate stability of endogenous 4βHC in plasma and the corresponding DPE derivative for the analysis of clinical study samples. The results from clinical samples following treatment with a potent P450 3A inducer (rifampin) or inhibitor (ketoconazole) are reported and demonstrate the potential future application for this highly precise and robust analytical assay.

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Derivatization-independent cholesterol analysis in crude lipid extracts by liquid chromatography/mass spectrometry: Applications to a rabbit model for atherosclerosis

Cited by 68 publications

References 40 publications

Cidea Control of Lipid Storage and Secretion in Mouse and Human Sebaceous Glands

Cidea Control of Lipid Storage and Secretion in Mouse and Human Sebaceous Glands

Extensive characterization of human tear fluid collected using different techniques unravels the presence of novel lipid amphiphiles

Quantification of 4-Beta-Hydroxycholesterol in Human Plasma Using Automated Sample Preparation and LC-ESI-MS/MS Analysis

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