Serum Histones in Dogs with Septic Peritonitis as a Prognostic Biomarker

Septic peritonitis (SP) is a life-threating condition. Determining prognosis for dogs suffering from SP remains challenging. Extracellular histones exert cytotoxic, prothrombotic and proinflammatory effects. Our objective was to investigate serum general histone concentrations (sHs) as biomarkers of disease severity and outcome in dogs with naturally occurring SP. Blood samples were collected upon admission and 24 hours post admission from 21 dogs with SP and from 7 healthy controls. Serum general histone concentrations (median; IQR) upon admission were higher in dogs with SP compared to controls (34.2 ng/ml; 39.1 ng/ml vs. 7.3 ng/ml; 1.7 ng/ml; P=0.001) and sHs significantly decreased 24 hours post admission in dogs with SP (34.4 ng/ml; 39.3 ng/ml vs. 24.2 ng/ml; 11 ng/ml; P=0.018). Serum histones were higher among survivors compared to non-survivors (45.5 ng/ml; 37 ng/ml vs. 24.0 ng/ml; 12 ng/ml; P=0.03). This data demonstrates that sHs concentrations significantly increase in dogs with SP and decrease after hospitalization. Future studies are warranted to investigate the reverse relationship between outcome and sHs.