Kinetics of Plasma Cell‐Free DNA and Creatine Kinase in a Canine Model of Tissue Injury

Abstract

BackgroundCell‐free DNA (cfDNA) comprises short, double‐stranded circulating DNA sequences released from damaged cells. In people, cfDNA concentrations correlate well with disease severity and tissue damage. No reports are available regarding cfDNA kinetics in dogs.Objectives/HypothesisCell‐free DNA will have a short biological half‐life and would be able to stratify mild, moderate, and severe tissue injury. Our study aims were to determine the kinetics and biological half‐life of cfDNA and to contrast them with those of creatine kinase (CK).AnimalsThree groups of 10 dogs undergoing open ovariohysterectomy, surgery for cranial cruciate ligament rupture (CCLR), or hemilaminectomy.MethodsPlasma for cfDNA and CK analysis was collected at admission, at induction of anesthesia, postsurgery (time 0) and at 6, 12, 24, 36, 48, 60, and 72 hours after surgery.ResultsThe biological half‐life of plasma cfDNA and CK were 5.64 hours (95% confidence interval [CI 95], 4.36–7.98 hours) and 28.7 hours (CI95, 25.3–33.3 hours), respectively. In the hemilaminectomy group, cfDNA concentrations differed significantly from admission at 6–12 hours after surgery. Creatine kinase activity differed among the surgical groups and reached a peak 6 hours after surgery. In the ovariohysterectomy and CCLR groups, plasma CK activity 72 hours after surgery did not differ from admission activity of the ovariohysterectomy group. In contrast, in the hemilaminectomy group, plasma CK activity after 72 hours did not return to the ovariohysterectomy group admission activity.Conclusions and Clinical ImportancePlasma CK activity has a longer biological half‐life than previously thought. In contrast to plasma CK activity, cfDNA has a short half‐life and could be a useful marker for peracute severe tissue injury.

Horizons in Veterinary Precision Oncology: Fundamentals of Cancer Genomics and Applications of Liquid Biopsy for the Detection, Characterization, and Management of Cancer in Dogs

“…Among these contents are fragments of DNA, known as "cell-free DNA" once they have left the confines of the cell and its nucleus. These cfDNA fragments are rapidly degraded by normal metabolic processes and have a very short half-life, estimated at 15 min to a few hours in both humans and dogs; as a result, they are usually cleared within a few days (168)(169)(170). The constant turnover of cells throughout the body provides a steady supply of cfDNA in the circulation, which is amenable to analysis with sophisticated technologies including NGS.…”

“…Published research on canine cfDNA has covered a variety of clinical applications, including trauma, sepsis, thromboembolism, and neoplasia, and has focused primarily on determining the concentration of cfDNA in plasma as correlated to a particular clinical state or as a predictor for certain clinical outcomes ( 84 , 148 – 151 , 167 , 169 , 191 – 203 ). Studies that evaluated cfDNA concentrations in healthy canine subjects have reported median concentrations ranging from less than 1 ng/mL to greater than 500 ng/mL ( 148 , 149 , 167 , 169 , 194 – 203 )—significantly wider than the range documented in healthy humans (typically 0–20 ng/mL) ( 204 ). These wide-ranging findings suggest that additional research employing well-controlled, large-scale studies is required to better understand the fundamental characteristics of cfDNA in dogs; they also point to the need for standardized, reproducible methods for blood collection, extraction, and measurement of canine cfDNA.…”

Life and death of circulating cell-free DNA

“…33,34 Elevated cfDNA might also reflect physiological (e.g., exercise) 35,36 and non-malignant pathological processes, 7 such as inflammation, diabetes, tissue trauma, sepsis, and myocardial infarction. [37][38][39] The concentration of cfDNA in blood varies significantly; it ranges between 0-5 and >1000 ng/ml in patients with cancer and between 0 and 100 ng/ml in healthy subjects. 7,24 There is also a marked variation in blood ctDNA levels among patients with different tumor types.…”

Interest of circulating tumor DNA as a biomarker for canine cancers: illustration in histiocytic sarcoma, oral malignant melanoma and multicentric lymphoma

“…In veterinary medicine, cfDNA has recently gained attention and more particularly in dogs. As in human medicine, it has been found that cfDNA has a short half-life in canine plasma (around 5 hours) 15 and its concentration is increased in various diseases such as immune-mediated hemolytic anemia 16 , sepsis, severe trauma or inflammation [17][18][19] . In dogs, cfDNA concentration is also correlated with the severity of the disease and prognosis 18 .…”