Recovery and functional activity of mononuclear bone marrow and peripheral blood cells after different cell isolation protocols used in clinical trials for cell therapy after acute myocardial infarction

AIMS: Clinical trials showed contradictory results in functional recovery after intracoronary infusion of autologous mononuclear (bone marrow) cells in patients with acute myocardial infarction. A recent study suggests that this might be related to the isolation protocol used. In The Netherlands, a comparable randomised multicentre trial (HEBE) was designed. To validate the isolation method of bone marrow and peripheral blood-derived mononuclear cells, we compared our processing protocol with methods comparable to the ASTAMI (no beneficial effect) and the REPAIR-AMI study (beneficial effect). METHODS AND RESULTS: The effect of several factors (density gradient, washing buffer and centrifugation speed) has been studied on recovery and function (migration and clonogenic capacity) of mononuclear cells. Significantly lower cell recoveries were found at a centrifugation speed of 250 g, compared to 600 or 800 g, respectively. Furthermore, washing buffer without supplemented human serum albumin and heparin resulted in significantly lower cell recovery and functional impairment as measured by clonogenic capacity. CONCLUSIONS: The results of our study justify the cell-processing protocol as applied in the HEBE trial (600 g, human serum albumin supplemented washing buffer). This protocol results in viable and functional cells of which the quantity and quality is at least comparable to a successful study like the REPAIR-AMI