Levels of 7-oxocholesterol in cerebrospinal fluid are more than one thousand times lower than reported in multiple sclerosis

Abstract

1), high levels of the cholesterol oxidation product 7-oxocholesterol were reported in cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS): ‫ف‬ 7 mg/l. Unsurprisingly, such high levels were found to cause neuronal damage under in vitro conditions. The levels were considerably lower in CSF from control subjects: ‫ف‬ 0.5 mg/l. In a previous work from this laboratory, we measured levels of 7-oxygenated oxysterols in CSF from different groups of patients (2), and the levels were always found to be less than 0.01 mg/l (our unpublished observation). It is well established that the other oxysterols in CSF, 24 S -hydroxycholesterol (24OHC) and 27-hydroxycholesterol (27OHC), are present in similarly low concentrations (3-6). In view of this, and in view of the suggestion by Diestel et al.(1) that 7-oxocholesterol could be an important link between demyelination and neuronal damage, we measured the levels of 7-oxocholesterol in CSF from 29 Swedish patients with MS and 24 control subjects. A highly accurate and sensitive method was used based on isotope dilution-mass spectrometry (ID-MS) using deuterium-labeled internal oxysterol standards. The results are discussed in relation to the fact that 7-oxygenated steroids are easily artificially formed by autoxidation of cholesterol during workup procedures and analysis of sterols and oxysterols from biological samples.

Crystal Structures of Trypanosoma brucei Sterol 14α-Demethylase and Implications for Selective Treatment of Human Infections

“…Similar to sterols in animals and plants, they can serve as precursors for biologically active molecules essential for the growth and development processes (45), and therefore, potent 14DM inhibitors might be helpful in combination with immunostimulants with traditional antisleeping sickness drugs to decrease their effective dosage and thus ease the burden of toxicity, adverse side effects, and resistance. Because azoles are generally known to cross the bloodbrain barrier (47), they might be advantageous in the chronic stage of the disease when the parasite enters the central nervous system because in the cerebrospinal fluid, the source of cholesterol becomes hundreds of times more limited (48). More detailed studies are underway, and we believe that identification of regulatory sterols in T. brucei will not only advance knowledge of protist biology but may uncover novel parasitespecific drug targets as well.…”

Cardioprotection by the TSPO ligand 4′-chlorodiazepam is associated with inhibition of mitochondrial accumulation of cholesterol at reperfusion

“…40 In particular, oxysterols are involved in the development of atherosclerosis and in the genesis of neurodegenerative diseases, 29 and it had been suggested that they may be biomarkers in these diseases. 41 7-Ketochol and 7bOHC induce downregulation of anti-oxidative defences 42 and most of the toxic effects of oxysterols have been attributed to their ability to induce apoptosis through the mitochondrial pathway. 29 In the present study, we show that reperfusion induces lipid peroxidation of mitochondrial membranes as demonstrated by the increase in conjugated dienes and TBARs.…”

Conversion of 7-ketocholesterol to oxysterol metabolites by recombinant CYP27A1 and retinal pigment epithelial cells

“…We also knew that 7KCh is one of the most diffi cult oxysterols to measure because even minor auto-oxidation of highly abundant cholesterol during sample isolation and workup will lead to falsely high levels of 7KCh and overestimation of its content by as much as a 1,000-fold ( 35 ). We were also aware that to accurately quantify 7KCh, as well as any other sterol, its deuterated analog should be added to a biological sample prior to the beginning of any manipulations.…”

“…Several precautions were taken to avoid artifi cial autooxidation of cholesterol to 7KCh during the workup of biological samples ( 35 ). Only tissues immediately isolated from fresh bovine eyes (3-5 h postmortem according to the slaughterhouse) were used, and BHT and EDTA were always included in the buffer for tissue homogenization.…”