Defibrase

To evaluate the therapeutic effect of individualized defibrase therapy according to the level of plasma fibrinogen (FIB) in patients with acute cerebral infarction (ACI).

Sixty patients with ACI (within 72 h after onset) were randomly divided into defibrase group (n=30) and control group (n=30). The patients in defibrase group received intravenous defibrase infusion at different first doses (15, 10, and 5 U) according to plasma FIB level (>4 g/L, 2-4 g/L, and 1.3-2 g/L) before treatment. Plasma FIB was measured every 12 h after the first dose of defibrase, and when plasma FIB was over 1.3 g/L, intravenous infusion of 5 U defibrase was given to maintain plasma FIB within the range of 0.70-1.13 g/L over a period of 7 days. The plasma prothrombin time (PT), activated partial thromboplastin time (APTT) and FIB before and after the 7-day treatment were measured, and the scores of Chinese stroke scale (CSS) after 14 days of treatment and Activity of Daily Living (ADL) after 3 months were recorded.

After 7 days of treatment, plasma PT and APTT were significantly prolonged lengthened and plasma FIB was lowered in defibrase group. The scores of CSS improved in defibrase group after 14 days of treatment, showing significant difference from those of the control group. The clinical effective rate was 80% in defibrase group, significantly higher than that in the control group (50%). The scores of ADL after 3 months were similar between the 2 groups, but the percentage of independent living and mild dependency was significantly higher in defibrase group (93.3% vs 70.0%). No intracerebral and extracerebral hemorrhage occurred in defibrase group the during treatment, no did death occur after 3 months of treatment.

Defibrase therapy based on plasma FIB level can rapidly and effectively lower plasma FIB, reduce neurological impairment and improve the quality of life in patients with ACI.

Recombinant Harobin exhibits an amidolytic activity, and specifically degrades Aα, Bβ‐chain of fibrinogen. It functions as a defibrase both in vitro and in vivo, and reduces thrombosis. Harobin prolongs the coagulation time and the bleeding time of mice and reduces the fibrinogen levels of rats as well. Meanwhile, intravenous injection of Harobin leads to the reduction of blood pressure in SHR rats. It results from the ability of Harobin that cleaves angiotensin I and release bradykinin from plasma kininogen in vitro and in vivo. These data suggest that Harobin is a novel defibrase and has a potential to be an agent for the therapy of thrombosis and hypertension.