Factor VIII (FVIII) replacement therapy remains a primary treatment for hemophilia A, however, development of FVIII antibodies (inhibitors) and short half-life of the FVIII products are the major complications. Erythrocytes as a biocompatible and non-immunogenic drug delivery system protect drugs from rapid removing in the circulation. In this study, in vitro activity of FVIII encapsulated by human erythrocytes was investigated.
Materials and Methods:
FVIII was loaded into erythrocytes using the hypo-osmotic dialysis technique. FVIII activity assay is analyzed using activated partial thromboplastin time (APTT). Presence of FVIII on erythrocytes was detected by western blotting and flowcytometry using specific monoclonal antibody (abcam, U.K) against FVIII. Moreover, the osmotic fragility and hematologic parameters of FVIII -loaded carrier erythrocytes were measured.
Our results indicated that FVIII could not cross the membrane, where plenty of FVIII was found on the surface of carrier erythrocyte. Flow cytometery results showed that 11% of the loaded carrier erythrocyte was positive for FVIII protein on their surface.
The most FVIII activity in both groups including lysate and non-lysate FVIII-loaded RBCs was observed on the first day, and coagulant activity of this factor was gradually reduced on days 3 and 5. In 1:50 dilution of both groups, we observed a meaningful difference in FVIII activity, especially on 5th day.
This study aims to introduce erythrocytes as appropriate carriers for FVIII to prolong the dosing intervals in the effective and safe levels for a relatively longer time.