Protein Z and vitamin K in kidney disease
Malyszko JS, Malyszko J, Skrzydlewska E, Pawlak K, Mysliwiec M

Purpose: Disturbances in hemostasis are common complications of kidney diseases. Both bleeding diathesis and thromboembolism may complicate the course of chronic uremia. As far as we know, there is a limited data about protein Z in kidney disease.
Material and methods: The aim of our work was to examine plasma protein Z and vitamin K concentrations in nephrotic syndrome (n=34), glomerulonephritis (n=48), kidney transplant recipients (n=80), peritoneally dialyzed patients (n=42) and in the healthy volunteers (n=27).
Results: Vitamin K was significantly lower in nephrotic syndrome when compared to non-nephrotic patients, CAPD and healthy volunteers (p<0.05). Protein Z was the highest in CAPD and kidney transplant recipients when compared to any other group. In nephrotic syndrome protein Z was significantly lower when compared to the healthy volunteers, but it did not differ significantly between two groups of patients with chronic renal failure (with and without nephrotic syndrome). Protein Z correlated only with fibrinogen in CAPD, glomerulonephritis and nephrotic patients. Vitamin K correlated with age and albumin in patients with glomerulonephritis, nephrotic syndrome as well as with albumin in CAPD. 
Conclusions: Alterations in protein Z might contribute to the enhanced risk of thromboembolic complications in nephrotic syndrome, CAPD and Tx via different and unknown mechanisms. This phenomenon seems to be unrelated to vitamin K status in these patients.

Key words:   vitamin K, protein Z, kidney disease.