Oxysterols 15HC and 15KC.
Oxysterols, oxidized cholesterol derivatives, are a subject of much discussion and controversy; while some in vitro experiments have suggested that oxysterols are biologically important, they only are present in trace amounts in the plasma, and no in vivo studies have shown a definitive role. Therefore, there was great interest when a recent study reported that two oxysterol species, 15HC and 15KC, were increased more than three-fold in the blood of multiple sclerosis patients, suggesting a potential use for these oxysterols as diagnostic biomarkers.
In this Journal of Lipid Research study, the researchers performed their own analysis of blood samples using gas chromatography-mass spectrometry to validate these exciting findings; however, despite numerous efforts, the researchers failed to find any significant 15HC or 15KC levels in blood of either healthy individuals or MS patients. To validate their protocol, the team also tested samples with pre-loaded oxysterols and recovered almost 100 percent of the loaded amount, confirming that the oxysterols were not being lost somewhere along the experimental process.
Given the conflicting results of these two recent studies, the potential role of oxysterols in MS needs to be reconsidered.
High levels of 15-oxygenated steroids in circulation of patients with multiple sclerosis: Fact or fiction?
Ingemar Bjorkhem, Anita Lovgren-Sandblom, Fredrik Piehl, Mohsen Khademi, Hanna Petersson, Valerio Leoni, Tomas Olsson, and Ulf Diczfalusy
J. Lipid Res., published online Oct. 7
Companion editorial: Are 15-oxygenated sterols present in the human circulation?
William Griffiths and Yuqin Wang
J. Lipid Res., published online Oct. 18