The investigation of serum protein profiles in anal fistula for potential biomarkers

Abstract

Abstract Objectives An anal fistula is an external abnormal anatomical connection between the rectum and the outer skin of the anus. Symptoms include anorectal pain, abscesses, perianal cellulitis, smelly or bloody drainage of pus, and, in some cases, difficulty controlling bowel movements. Diagnosis and evaluation of anal fistulas is crucial for prognosis and for the choice of the treatment method. In this study, we aimed to discover potential biomarkers from serum proteins for the prediction of anal fistulas. Methods Using antibody array technology, the expression of 40 proteins was simultaneously detected in serum samples from 13 patients with anal fistulas with chronic diarrhea, 14 patients with chronic diarrhea and six healthy volunteers. Differentially expressed proteins were subsequently validated by ELISA, with a sample population expanded to 30 patients with anal fistulas and chronic diarrhea, 30 patients with chronic diarrheas only and 20 healthy controls. Results Quantification analysis identified MIP-1α, MIP-1β and TNF-R1 with significant differential expression between the anal fistula with chronic diarrhea, chronic diarrhea only and healthy control groups. Bioinformatics analyses, including PCA and heat map creation, showed a clear separation between the three groups using the expression of MIP-1α, MIP-1β and TNF-R1. Validation by ELISA with the expanded sample population fistulas showed significant differential expression levels of MIP-1α, MIP-1β and TNF-R1, displaying accuracy rates of 0.898, 0.987 and 1.0 between the anal fistula with chronic diarrhea and healthy control groups. Accuracy rates between the anal fistula with chronic diarrhea and the chronic diarrhea only groups were 0.9768, 0.909 and 0.964, respectively. Conclusions These results suggest the feasibility of employing serum proteins MIP-1α, MIP-1β and TNF-R1 as potential biomarkers for rapid and convenient diagnosis of anal fistula in chronic diarrhea patients.