Mass Spectrometry Imaging

Mass Spectrometry Imaging

MS imaging of brain

 

Steroid hormones circulate in blood and penetrate tissues where they have their actions. The amounts of steroids in tissue subregions can be modulated by local enzymes and transporters, making it vital to understand regional steroid amounts e.g. in inflamed sites, in tumours or in brain regions. Mass spectrometry imaging is a powerful technique used to localise molecules in tissue sections, providing molecular distribution. Research (funded by the BHF and MRC) has allowed development of approaches which reveal the tissue distribution of steroids in complex tissues. Steroids are difficult to ionise by mass spectrometry making them difficult to discern in complex biomatrices, but novel charge tagging approaches have been established revealing their distribution within small cell clusters. Our first studies localised glucocorticoids within adrenal and brain tissue. allowing evaluation of the pharmacokinetics/pharmacodynamics of inhibitors of 11ß-hydroxysteroid dehydrogenase type 1. Recently work involving Mass Spectrometry imaging of androgens has been accepted in Analytical Chemistry, (Cobice et al. Anal Chem 2016).  Future studies will involve the use of ion mobility to resolve steroid isomers, with installation of a new MS facility in the Spring 2017 under Wellcome Trust Funding.

Figure 1. MS image of testosterone and dihydrotestosterone, charge tagged to be detected in mouse testes.

MS Imaging studies have been funded by the MRC and BHF and published in Analytical Chemistry (Cobice et al 2013 and 2016). MS Imaging has been carried out in collaboration with Dr L MacKay (SIRCAMS).