OBJECTIVETo study the alteration of protein Z (PZ) in patients with cardio-cerebral thrombotic diseases, its clinical significance and relations with FX.

METHODSPZ and FX:Ag were measured by ELISA, and plasma FX:C by first stage method. In 170 patients with acute ischemic stroke (AIS), 40 acute myocardial infarction (AMI) and 60 healthy adults as contrast, PZ, FX:C and FX:Ag were measured and compared between incipience and recurrence, different ages and genders.

RESULTSIn AIS and AMI groups, PZ levels decreased significantly to (940.02 +/- 229.82) microg/L and (1071.44 +/- 180.52) microg/L, respectively \[the contrast group was (2257.97 +/- 479.76) microg/L, P < 0.001\]. But FX:C and FX:Ag raised to (136.73 +/- 34.93)% and (135.54 +/- 54.39)% in AIS group; and to (139.53 +/- 29.18)%, (129.75 +/- 21.91)% in AMI group, respectively, while in the contrast group they were (94.33 +/- 22.00)% and (77.22 +/- 13.19)% (P < 0.001). In the comparative research between the AIS group, AMI group and the contrast group, PZ level was clearly found to negatively relate to the level of FX:C and FX:Ag (P < 0.001). Meanwhile, PZ level, FX:C and FX:Ag in recur-AIS group and recur-AMI group exhibited significant differences (P < 0.05) from those in the primary AIS and AMI groups, suggesting that the decrease of PZ levels reflected the pathological process of the disease. In addition, PZ level gradually decreased with the increase of age (P < 0.05), while FX:C and FX:Ag had no relations with age (P > 0.05). No correlation was found in sex with PZ level, FX:C, FX:Ag (P > 0.05).

CONCLUSIONPZ level was significantly decreased in AIS and AMI patients and was negatively related to FX:C and FX:Ag. The mechanism leading to FX increase may partially related with the decreased of PZ. PZ level was different in the primary and recurrent disease and was gradually decreased with the increase of age. Lack of PZ might be a etiological factor of cardio-cerebral thrombotic diseases.