Mass spectrometry-based proteomic analysis of the effect of storage temperature on non-invasively collected samples of human stratum corneum.

PURPOSE: The collection of human stratum corneum (SC) samples by tape-stripping promises to deliver a non-invasive method for biomarker analysis of skin diseases. The current study examines the effect of storage temperature and SC layer depth on the proteome profile of SC samples. EXPERIMENTAL DESIGN: The samples were collected from healthy volunteers (n = 5) using 10 sequential adhesive discs. Discs were pooled by five (discs 1-5, 6-10) and stored at various temperatures for 10 days before their analysis by mass spectrometry. RESULTS: No statistically significant difference was seen in the protein yield between discs 1-5 (14.8 mg) and 6-10 (14.4 mg), or between discs stored at -80°C (14.7 mg), -20°C (15.8 mg), 4°C (14.9 mg) or room temperature (13.2 mg). Mass spectrometry analysis revealed that the storage of SC samples at higher temperatures does not affect their proteome profile considerably (< 4.7% peptide precursor loss at lower temperatures vs. -80°C). On the other hand, while 95.3% of the identified peptide precursors were shared between discs 1-5 and 6-10, the level of 17 proteins was significantly changed between these conditions. CONCLUSIONS: The findings of this study will likely have major implications on the conduct of proteomic studies involving SC sample collection, storage, and transportation.