Long-term preservation of bone marrow and stem cell pool in dogs.

A canine model in vivo was established to assess the viability of stem cells frozen and stored for prolonged periods in liquid nitrogen. Forty-six foxhounds received totalbody irradiation (1000 rods at 9 rods/mm) followed by the infusion of autologous fresh bone marrow or frozen bone marrow stored for 2 or 5 mo in the vapor phase of liquid nitrogen (140#{176}C). The results demonstrated a direct relationship between the dose of bone marrow infused, the percentage of successful engraftments, and the kinetics of peripheral recovery. The minimum dose of fresh bone marrow for autologous engraftment was between 0.1 and 0.25 x 108 nucleated cells/kg. There was no difference between fresh bone marrow and bone marrow stored for 2 ma (100% recovery of frozen stem cells). Following a 5-mo storage period, the results suggested a slight but not statistically significant decrease in stem cell viability. If it could be demonstrated that this technique successfully preserves human bone marrow stem cells, these data would support the inclusion of frozen autologous bone marrow rescue in the management of patients with malignant diseases as an adjunct to ablative chemotherapy.