Extracted Plasma Cell-Free DNA Concentrations Are Elevated in Colic Patients with Systemic Inflammation

Colic is a common and potentially life-threatening condition in horses; in many cases, it remains challenging for clinicians to determine the cause, appropriate treatment, and prognosis. One approach that could improve patient care and outcomes is identification of novel diagnostic and prognostic biomarkers. Plasma cell-free DNA (cfDNA) is a biomarker that shows promise for characterizing disease severity and predicting survival in humans with acute abdominal pain or requiring emergency abdominal surgery. In horses, we recently determined that extracted plasma cfDNA concentrations are elevated in colic patients compared to healthy controls. For this current study, we hypothesized that extracted plasma cfDNA concentrations would be significantly higher in horses with strangulating or inflammatory colic lesions, in colic patients with systemic inflammatory response syndrome (SIRS), and in non-survivors. Cell-free DNA concentrations were measured in extracted plasma samples using a compact, portable Qubit fluorometer. Colic patients that met published criteria for equine SIRS had significantly higher median extracted plasma cfDNA compared to non-SIRS colic patients. There were no significant differences in extracted plasma cfDNA concentrations between other groups of interest. Our data offer early evidence that extracted plasma cfDNA concentration may provide information about systemic inflammation in colic patients, and additional research is warranted to expand on these findings.