Determination of Cholesterol Oxidation Products in Human Plasma by Isotope Dilution-Mass Spectrometry

Dzeletovic, S.; Breuer, Olof; Lund, Erik; Diczfalusy, Ulf

doi:10.1006/abio.1995.1110

Cited by 517 publications

(480 citation statements)

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“…In tissues or cells, 25-OHC is synthesized from cholesterol by cholesterol 25-hydroxylase [20]. In general, however, low levels (several nM) of 25-OHC are present in human plasma [21]. Therefore, administration of 25-OHC may be one of practical approaches for the treatment of allergic inflammation.…”

Section: Discussionmentioning

confidence: 99%

Oxysterol represses high‐affinity IgE receptor‐stimulated mast cell activation in Liver X receptor‐dependent and ‐independent manners

Nunomura¹,

Endo²,

Makishima³

et al. 2010

FEBS Letters

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a b s t r a c tOxysterols activating liver X receptors (LXRs) repress expression of pro-inflammatory genes and have anti-inflammatory effects. Here, we show for the first time that bone marrow-derived murine mast cells (BMMCs) predominantly express LXRb. 25-hydroxycholesterol, a representative LXR activating oxysterol, suppressed IL-6 production and degranulation response in BMMCs following engagement of high-affinity IgE receptor (FceRI). Interestingly, 25-hydroxycholesterol reduced cell-surface FceRI expression by inhibiting assembly of FceRIa and FceRIb. We demonstrate that LXR activation was involved in the suppression of IL-6 production in BMMCs, but that reduced FceRI expression and degranulation response was mediated in an LXR-independent manner.

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Section: Discussionmentioning

confidence: 99%

Oxysterol represses high‐affinity IgE receptor‐stimulated mast cell activation in Liver X receptor‐dependent and ‐independent manners

Nunomura¹,

Endo²,

Makishima³

et al. 2010

FEBS Letters

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“…Traditionally, oxysterols are analyzed by GC-MS after derivatization of the hydroxyl groups to trimethylsilyl ethers [31,32]; alternatively cholesterol-like molecules can be analyzed by ES-MS and ES-MS/MS after one of a number of different derivatization reactions [53]. In the current study, molecules with a C 5 -3␤-ol structure have been oxidized to 3-oxo-⌬ 4 steroids and then derivatized to GP hydrazones.…”

Section: Sensitivity Of Analysismentioning

confidence: 99%

“…Traditionally, oxysterols have been analyzed by isotope-dilution gas-chromatography-mass spectrometry (GC-MS) [31,32]. However, high-performance liquid chromatography (HPLC) methods have been intro- Scheme 1.…”

mentioning

confidence: 99%

Analysis of oxysterols by electrospray tandem mass spectrometry

Griffiths

Wang

Alvélius

et al. 2006

J. Am. Soc. Mass Spectrom.

104

102

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Oxysterols are oxygenated derivatives of cholesterol. They are intermediates in cholesterol excretion pathways and may also be regarded as transport forms of cholesterol. The introduction of additional hydroxyl groups to the cholesterol skeleton facilitates the flux of oxysterols across the blood brain barrier, and oxysterols have been implicated in mediating a number of cholesterol-induced metabolic effects. Oxysterols are difficult to analyze by atmospheric pressure ionization mass spectrometry on account of the absence of basic or acidic functional groups in their structures. In this communication, we report a method for the derivatization and analysis of oxysterols by electrospray mass spectrometry. Oxysterols with a 3␤-hydroxy-⌬ 5 structure were converted by cholesterol oxidase to 3-oxo-⌬ 4 steroids and then derivatized with the Girard P reagent to give Girard P hydrazones, which were subsequently analyzed by tandem mass spectrometry. The improvement in sensitivity for the analysis of 25-hydroxycholesterol upon oxidation and derivatization was over 1000. (J Am Soc Mass Spectrom 2006, 17, 341-362)

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“…Alkaline hydrolysis was with sodium hydroxide followed by extraction with cyclohexane and derivatisation. To measure 24S--and 27--hydroxycholesterol, 2.5 mg of tissue extract was used with 100 ng d3 24 hydroxycholesterol and 25 ng d5 27 hydroxycholesterol (Dzeletovic et al, 1995). Sample processing included an alkaline hydrolysis step using potassium hydroxide, followed by solid phase extraction using silica columns and derivatisation with TMS.…”

Section: Introductionmentioning

confidence: 99%

Bi-lateral changes to hippocampal cholesterol levels during epileptogenesis and in chronic epilepsy following focal-onset status epilepticus in mice

Heverin

Engel

Meaney³

et al. 2012

Brain Research

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Brain cholesterol homeostasis has been shown to be disrupted in neurodegenerative conditions such as Alzheimer's and Huntington's diseases. Investigations in animal models of seizure--induced brain injury suggest that brain cholesterol levels are altered by prolonged seizures (status epilepticus) and are a feature of the pathophysiology of temporal lobe epilepsy. The present study measured hippocampal sterol levels in a model of unilateral hippocampal injury triggered by focal--onset status epilepticus, and in chronically epileptic mice. Status epilepticus was induced by intra--amygdala microinjection of kainic acid and ipsilateral and contralateral hippocampus analyzed. No significant changes were found for ipsilateral or contralateral hippocampal levels of desmosterol or lathosterol at any time after SE as measured by gas chromatographymass spectrometry. 24S--hydroxycholesterol and cholesterol levels were unchanged up to 24 h after status epilepticus but were decreased in the ipsilateral hippocampus during early epileptogenesis and in chronically epileptic mice. Levels of cholesterol were also reduced in the contralateral hippocampus during epileptogenesis and in chronic epileptic mice. Treatment of mice with the anti--inflammatory cholesterol synthesis inhibitor lovastatin did not alter seizures during status epilepticus or seizure--induced neuronal death. Thus, changes to hippocampal cholesterol homeostasis predominantly begin during epileptogenesis, occur bi--laterally even when the initial precipitating injury is unilateral, and continue into the chronic epileptic period.

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Determination of Cholesterol Oxidation Products in Human Plasma by Isotope Dilution-Mass Spectrometry

Cited by 517 publications

References 0 publications

Oxysterol represses high‐affinity IgE receptor‐stimulated mast cell activation in Liver X receptor‐dependent and ‐independent manners

Oxysterol represses high‐affinity IgE receptor‐stimulated mast cell activation in Liver X receptor‐dependent and ‐independent manners

Analysis of oxysterols by electrospray tandem mass spectrometry

Bi-lateral changes to hippocampal cholesterol levels during epileptogenesis and in chronic epilepsy following focal-onset status epilepticus in mice

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