Comparison of suction blistering and tape stripping for analysis of epidermal genes, proteins and lipids.

Analysis of epidermal genes, proteins and lipids is important in the research and diagnosis of skin diseases. Although punch biopsy is the first-choice technique for the skin sampling, it is unnecessarily invasive for obtaining a sample just for the epidermal analysis. Here we compare two less invasive methods, suction blistering (SB) and tape stripping (TS), for the analysis of selected epidermal genes (quantitative real-time reverse transcription PCR, qRT-PCR), proteins (western blotting, WB), and lipids in ten healthy volunteers. TS provided significantly less material than SB and no viable epidermal layers could be obtained according to the reflectance confocal microscopy. Consistently, only the SC protein filaggrin and housekeeping GAPDH together with FLG and RPL13A mRNA were detected by TS. In the SB samples, WB and qRT-PCR could easily detect all the selected proteins (claudin-1, occludin, filaggrin, laminin and GAPDH) and genes (CLDN1, OCLN, FLG, LAMA3 and RPL13A), respectively. A single SB sample further provided enough of material for immunohistochemistry and lipid analyses, which was not feasible with the TS samples. Immunohistochemistry of the SB samples showed intact epidermal structure and a characteristic expression of claudin-1. Infrared spectroscopy showed well-ordered lipids with both orthorhombic and hexagonal packing and high-performance thin layer chromatography confirmed all lipid classes (including ceramide subclasses) in correct proportions. Taken together, SB represents a reliable sampling technique that can be utilized for multipurpose epidermal analyses in various studies.