Searching for serum protein markers of equine squamous gastric disease using gel electrophoresis and mass spectrometry

Summary Background Equine squamous gastric disease (ESGD) is a very common disorder but an accurate and practical screening technique for detecting ESGD is currently lacking. Objectives To identify serum protein markers to detect ESGD using electrophoresis and mass spectrometry. Study design Proteomic analysis and bioinformatics. Methods ESGD was diagnosed using gastroscopy in 30 horses. Gastric ulceration was categorised into three groups: normal, mild/moderate and severe ESGD. Pooled sera from each group were compared using 1D electrophoresis and mass spectrometry. The candidate proteins for ESGD markers were selected based on their specifically high expression in nonglandular stomach, and their association with gastric ulceration using public gene and protein databases. Results The prevalence of ESGD in this study was 43% (with mild/moderate ESGD at 33% and severe ESGD at 10%). The proteomic study revealed that the identified serum protein markers for normal equine stomach were B4GALNT2 and XDH. The marker for mild/moderate EGSD was KRT10, while the marker for severe ESGD was KLK13. Furthermore, markers for both ulcer types were SLC4A7, PPARG, FCGBP, PKP1, ASPRV1 and KRT5‐like proteins. Main limitations The functions of the identified proteins are not well characterised in horse. Proteomics is a tool for screening protein markers, but confirmation of putative protein markers with specific antibodies is required. Conclusions In total, 10 serum proteins found in this study may be used as putative markers for ESGD. However, confirmation of candidate proteins with specific antibodies in a larger study cohort is necessary before it can be used in the veterinary clinic or on horse farms. The Summary is available in Portuguese – see Supporting Information