Protein Z and natural anticoagulants in children on peritoneal dialysis and hemodialysis

Abstract

Hemostatic alterations due to abnormalities in the coagulation and fibrinolytic system may occur in dialysis patients. Protein Z (PZ) is a vitamin K-dependent coagulation protein promoting assembly of thrombin with phospholipid vesicles. The aim of this study was to investigate PZ and natural anticoagulants in children on hemodialysis (HD) and peritoneal dialysis (PD). Protein Z, protein C (PC), protein S (PS), antithrombin III (AT III), and fibrinogen levels were studied in 24 PD, 13 HD patients and 23 controls. Plasma PZ levels in patients on HD were significantly higher than those on PD and control group (p = 0.04, p = 0.03). We observed elevated PC, PS and AT III activities in children on PD when compared to controls (p = 0.011, p = 0.003, p < 0.001). In HD patients, only PS activity was increased compared to controls (p = 0.016). PC and PS activities did not differ between PD and HD patients whereas AT III activity was higher in PD patients compared to HD patients (p < 0.001). Normal/high levels of PC, PS and AT III suggest that children on PD or HD treatment do not seem to have an increased risk of thrombogenesis due to reduction of these proteins. Increased PZ levels, however, might contribute to the hemostatic alterations in children on HD treatment along with other well known abnormalities.

Protein Z, a protein seeking a pathology

“…Influenceo fr enal insufficiencyand haemodialysis is not clear:inarecent study, asignificant decrease(p=0.022) of PZ wasobservedin46patients with chronic renal diseaseeitheronhaemodialysis or without dialysis (59).H owever,t he difference wasn ot statisticallys ignificant when patients are divided in groups on haemodialysis (23 cases) or without haemodialysis (23 cases).N os ignificant variations were previouslyd escribed in afirst limiteds tudy on 12 adults with glomerulonephritis without nephrotic syndrome and noton haemodialysis (60).Incontrast to the study of Blyth et al 59, PZ levels were found to be enhanced in patients on haemodialysis (60).The main difference betweenthe twogroups of patients on haemodialysis is thatinone study (59),CRP wasslightlyincreased,whereasitwas in anormal range in the other one (60). Peritoneal dialysis doesnot seemtomodify PZ levels (60,61) In addition to the well-known PC deficiencyinthalassemia, ac lear decreaseo fP Zi sa lso observed ( 62). PZ levels are decreased (50.8% )i np atients with malignant tumours, and the deficiencywas morepronounced in the most advanced stages of the tumours (63).…”