Inflammatory marker analysis of uterine cytobrush samples helps identify mares with endometritis.

Abstract

OBJECTIVE: To evaluate inflammatory cytokine and chemokine concentrations in endometrial samples collected by cytobrush or swab as a potential screening diagnostic marker for equine endometritis. METHODS: 88 mares had endometrial samples collected, which included cytobrush, swab, and/or biopsy. Clinical reproductive records, reproductive ultrasound examination, endometrial cytology and culture results, and biopsy grading score were recorded. Fluorescent bead-based multiplex assays for the inflammatory markers interferon-&#x3b3;, interferon-&#x3b1;, IL-1&#x3b2;, IL-4, IL-10, IL-17A, soluble CD14, tumor necrosis factor (TNF)-&#x3b1;, C-C motif chemokine ligand (CCL)-2, CCL3, CCL5, and CCL11 were carried out from the endometrial cytobrush and swab samples in reproductively healthy mares and mares with endometritis in a prospective cross-sectional study. RESULTS: The endometrial cytobrush technique yielded higher inflammatory marker concentrations for mares with endometritis than endometrial swabs. Tumor necrosis factor-&#x3b1; was increased in endometrial cytobrush samples from estrous mares that had endometrial neutrophils on cytology (n = 14; median, 4,185 pg/mL; IQR, 1,318.8 to 7,530 pg/mL) compared to samples from mares without neutrophils on cytology (n = 68; median, 1,653 pg/mL; IQR, 672 to 3,606.8 pg/mL; CI, 288 to 3,715) and in mares with endometritis (n = 14; median, 4,185 pg/mL; IQR, 1,318.8 to 7,530 pg/mL) compared to mares without endometritis (n = 57; median, 1,718 pg/mL; IQR, 651.5 to 3,968 pg/mL; CI, 580 to 4,383). Finally, mares with uterine TNF-&#x3b1; concentrations < 3,942 pg/mL in combination with CCL5 concentrations < 15,985 pg/mL had a 100% chance of identifying as a mare with a healthy endometrium. CONCLUSIONS: Increased concentrations of TNF-&#x3b1; and CCL5 in endometrial cytobrush samples are identified in mares with inflammatory endometritis. CLINICAL RELEVANCE: Inflammatory markers measured from endometrial cytobrush samples could be used to identify mares for endometritis that may have false negative results.