Cell-free nucleic acids as biomarkers in dialyzed patients.

In this review, we discuss the origin, possible biological meaning, quantitative and qualitative changes in the concentrations of cell-free nucleic acids in human circulation with regard to renal failure and the process of dialysis. We focus on the inflammatory response and apoptosis known to be in close relationship not only with hemodialysis but also with different comorbidities frequently detected in hemodialyzed patients. 
Hemodialysis itself is able to promote the changes in the quantity and quality of circulating nucleic acid pool, but large spectrum of comorbidities in hemodialyzed subjects can further complicate the interpretations of results of cell-free nucleic acid analysis. Such analysis can provide additional information about the patient prognosis and monitor some aspects of comorbidity development. Recently, it has been shown that the analysis of cell-free nucleic acids may also be worthy in patients on peritoneal dialysis because the cell-free nucleic acids may also be detected in overnight effluents and their examination can be informative with regard to the functional state of the patient's peritoneum. 
We summarize what is recently known about the use of cell-free nucleic acids as biomarkers in patients with renal failure not only in hemodialysis but also in peritoneal dialysis and we describe the future perspectives in this field.