Autori: Grazia Maria Virzì, Sabrina Milan Manani, Anna Clementi, Anna Giuliani, Massimo de Cal, Lorena Fernando, Giovanni Giorgio Battaglia, Carlo Crepaldi, Claudio Ronco
Affiliazioni: Department of Nephrology, Dialysis and Transplant, St Bortolo Hospital, Vicenza, IRRIV- International Renal Resarch Institute, Vicenza, Italy
Background: Peritonitis and exit site infections are the major complications of Peritoneal Dialysis (PD). Erythrocytes (Red Blood Cells – RBCs) are extremely sensitive cells and they undergo programmed cell death, known as eryptosis which is similar to apoptosis. Little is known about the pathogenesis of eryptosis in PD patients, but recent reports have demonstrated enhanced eryptosis in PD patients compared to healthy subjects. The aim of this study was to evaluate the eryptosis level in PD patients with peritonitis and its relationship with conventional and unconventional inflammatory indices.
Material and Methods:
We enrolled 65 PD patients: 34 PD patients without any history of systemic inflammation and peritonitis in the last 3 months and 31 PD patients with acute episode of peritonitis. We assessed conventional (C-reactive protein) and unconventional (IL-1β and IL-6) inflammatory indices. Phosphatidylserine (PS) exposure at RBC surface, reflecting eryptosis, was estimated from FITC-AnnexinV binding using flow cytometric analyses in freshly isolated RBCs.
Results:
Eryptosis resulted significantly higher in PD patients with peritonitis (9.6%; IQR 4.2-16.7), compared to PD patients without peritonitis (2.7%; IQR 1.6-3.9)(p<0.0001)(Figure 1). Furthermore, we performed a sub-analysis in PD patients with peritonitis: the median percentage of eryptosis did not differ in patients with relapsing episode of peritonitis (p=0.32) (Figure 2) and in patients with refractory peritonitis (p=0.64)(Figure 3). The median values of all inflammatory markers resulted significantly higher in PD patients with peritonitis compared to PD patients without (p<0.0001).Significant positive correlations were observed between the percentage of eryptosis and all inflammatory markers.
Conclusion
In conclusion, we hypothesized a potential connection between eryptosis and the inflammatory peritoneal membrane damage, thus suggesting an additional tool to confirm the diagnosis of peritonitis. Anyway, these preliminary results should be considered as hypothesis generating, and may stimulate further exploration about the role of eryptosis in PD related peritonitis.