Plasma cholinesterase activity in patients during peritoneal dialysis

Introduction

Literature data suggest that the release of nitric oxide (NO) by endothelial NO synthase contributes to functional alterations of the peritoneal membrane induced by acute peritonitis. Experimental animal studies show that induced peritonitis was characterized by structural changes in the peritoneal membrane and increased permeability for urea and glucose, as well as increased protein loss in dialysate [1]. Plasma cholinesterase (PChE, 3.1.1.8) is an enzyme synthesized in the liver, molecular mass from 345,000 to 371,000 Da. The aim of this study was to evaluate the functional characteristics of the peritoneum, determining PChE transfer from blood to dialysis fluid in peritonitis-free patients and in patients with peritonitis.

Methods

We measured PChE activity in plasma and peritoneal dialysate in adult peritonitis-free patients (n = 20) and in patients with peritonitis (n = 12). For determination of PChE activity, vein blood samples were collected and stored at -20°C until analysed. PChE activity was determined by the spectrophotometric method of Ellman and colleagues [2], using butyryltiocholine as the substrate (Sigma Chemical Co., St Louis, MO, USA). Statistical analysis was made by Mann–Whitney U test and Wilcoxon matched-pairs test.

Results

In both groups of examined patients we detected the significant passage of PChE from blood to dialysis fluid (P = 0.000089 for peritonitis-free patients and P = 0.002218 for patients with peritonitis). The transperitoneal PChE passage degree is statistically unchanged in patients with peritonitis in relation to peritonitis-free patients (P = 0.119438).

Conclusion

In all patients we detected significant transperitoneal passage of PChE during peritoneal dialysis. During human peritoneal dialysis there is no peritoneal permeability change for macromolecules such as PChE protein complex in patients with peritonitis.