Blood cells are adhered to a substrate of interest (see Flow Adhesion), followed by introduction of anti-adhesive drug under flow. Remaining adherent cells are measured to generate a reverse adhesion index (rAI).
Blood samples pretreated with anti-adhesive therapies have been evaluated in in vitro flow systems to mimic prophylactic treatment. Equally important, the ability of anti-adhesive agents to reverse cell adhesion is of interest. Cells are allowed to adhere during physiologic flow. Anti-adhesive agent is flowed over adherent cells. Remaining cells are measured.
In a recent published experiment treatment of established cell adhesion by the test compound. A) Whole blood adhesion to immobilized VCAM-1 was established during physiologic flow. B) Microchannels were perfused with vehicle or the test compound during identical flow conditions. Images were acquired at 1 minute intervals. The effect of the test compound on cell adhesion was determined by the amount of adherent cells remaining following 30 minute drug perfusion. C) The test compound reversed established cell adhesion by > 30% in 3 of 10 patient samples tested, although the total average difference in percent detachment did not reach statistical significance (16.3% vs. 29.6%, p=0.42, n=10).