Parkinson’s disease (PD) is the second most common neurodegenerative disorder and identification of robust biomarkers to complement clinical diagnosis will accelerate treatment options. Here we demonstrate the use of direct infusion of sebum from skin swabs using paper spray ionisation coupled with ion mobility mass spectrometry (PS-IM-MS) to determine the regulation of molecular classes of lipids in sebum that are diagnostic of PD. A PS-IM-MS method for sebum samples that takes three minutes per swab was developed and optimised. The method was applied to skin swabs collected from 150 people and elucidates ~ 4200 features from each subject which were independently analysed. The data included high molecular weight lipids (>600 Da.) that differ significantly in the sebum of people with PD. Putative metabolite annotations of several lipid classes, predominantly triglycerides and larger acyl glycerides, were obtained using accurate mass, tandem mass spectrometry and collision cross section measurements.
In order to better characterise the components of sebum, and those that are altered with PD, we have performed additional experiments. We have used accurate mass and database searching as a first route for identification, coupled with tandem MS as well as the use of ion mobility data to provide collision cross sections values to compare with database CCS values for different lipid classes, and commercially available lipid standards. Following the robust, approach of identifying features of significant difference between PD and control, accurate mass searching, tandem MS and CCS matching, we identify major features due to glyceride lipids, principally triglycerides and diglycerides, as well as larger acyl-glycerides, these are more robust annotations that those previously suggested for phosphatidylcholine and cardiolipin species.
D.Sarkar PSI IM-MS Sebum Parkinsons disease SI