Protein Z levels in haemodialysis patients

Protein Z (PZ) is a vitamin K-dependent protein isolated from human and bovine plasmas. Although the exact role of PZ in the haemostatic system is presently unknown, it is suggested that PZ deficiency may cause bleeding tendency. Haemostatic alterations in end-stage renal failure (ESRF) are certainly complex and involve several abnormalities in the coagulation and fibrinolytic system. In order to elucidate the detail of the haemostasis in ESRF, we aimed to investigate PZ activity in haemodialysis patients. Therefore, we compared plasma PZ levels in 10 haemodialysis patients (6 M, 4 F, mean age 36+/-11) and 10 healthy normal controls (5 M, 5 F, mean age 34+/-8) in this study. We found mean plasma PZ levels in haemodialysis patients and healthy controls 6.95+/-2.93 microg/ml and 3.06+/-0.81 microg/ml, respectively (p<0.005). Increased level of PZ which influences the action of thrombin on its protein substrates and inhibitors may contribute to the haemostatis alterations in ESRF patients, in addition to other well known abnormalities in the coagulation and fibrinolytic system.