Are there anyone familiar with the measurement method of 27-hydroxycholesterol in peripheral tissues, such as subcutaneous fat or liver? I can not find methods for this oxycholesterol measurement.
Dear Chen - I hope that this search strategy in Medline help in your search.
Link = http://www.ncbi.nlm.nih.gov/pubmed/?term=Chemistry+Techniques%2C+Analytical%2FMETHODS+AND+27-hydroxycholesterol
Dear Ivanildo, Thanks for your recommendation. Actually, I am looking for analytic methods specific for 27-hydroxycholesterol in adipose tissue. Through the search strategy, most of the papers are discussing methods to measure cholesterol metabolites in blood samples. Do you have other suggestion?
Dear Chen - the keywords of your search are: Analytical Chemistry Techniques (major topic) and hydroxycholesterols/analysis and (Adipose Tissue OR liver) as subtopics. Using this search strategy in the Pubmed/Medline found only 5 references (see result in Link 1). On the other hand, if we omit the keywords “Adipose tissue” and “Liver”, we will get 27 bibliographic citations addressing the issue. However, will appear citations about the use of the laboratorial technique in any tissue/body fluid (Link 2). A tip for obtaining other relevant citations – In the Medline click the link “Related citations” located below any reference that you find relevant.
http://www.ncbi.nlm.nih.gov/pubmed/?term=Analytical+Chemistry+Techniques%5BMajor+Topic%5D+AND+Hydroxycholesterols%2Fanalysis+AND+(Adipose+tissue+OR+Liver)
http://www.ncbi.nlm.nih.gov/pubmed/?term=Analytical+Chemistry+Techniques%5BMajor+Topic%5D+AND+Hydroxycholesterols%2Fanalysis
Hi folks,
The basic principle of estimating the level of 27-OHC is the same regardless of the sample matrix - add internal standard, extract, clean up and run through the instrument (GC/LC-MS). If you are interested in getting the total sterol levels, you will also have to incorporate an hydroylsis step into the process too - typically methanolic KOH for a couple of hours. As a starting point I would look at one of the classical methods for extraction and try that - I have used a Dzeletovic-based method very successfully many times and it is similar to other approaches . With fat the trickiest parts will be the hydrolysis as you will have a substantially larger substrate pool for the hydrolysis procedure due to the stored TAG. The large amount of free fatty acids released will also complicate the extraction as it's possible that you will exceed the CMC etc. so you will need to do some optimisations etc. I would suggest that it might be worthwhil o do s series of recovery experiments using radiolabelled cholesterol to iron out the main issues.
Hope that's of some help!
-steve
I suggest to ask Dieter Lütjohann from Bonn/Germany. He should be able to provide you an adequate answer. He is also on researchgate. However, over the next two weeks on vaccation.....