Enhancement of fractionated bone marrow transplantation on hematopoietic cell homing in a mouse allogeneic model.

Background: The conventional method of bone mar row transplantation (BMT) requires a large quantity of bone marrow cells (BMC) transplanted by a single injection. However, the homing efficiency of BMC is low, because the emptying of available niches might be a continuous process after stem-cell death after irradiation. In this article, the death character of CD34 stem cells was directly detected, and a novel method of fractionated (Fr) BMT that aimed to better use each niche that was continuously emptied was developed.
Methods: Apoptosis and necrosis were detected using trivariate fluorescence-activated cell sorting after labeling cells with phycoerythrin-CD34-fluorescein isothiocyanate-Annix V-7-aminoactinomycin D. Fr-BMT was conducted in a model of allogeneic BMT, where the total dosage of BMC was divided into four doses, and each dose was administrated for 4 consecutive days at 24-hr intervals after lethal irradiation.
Results: CD34 cells underwent a continuous death process after lethal irradiation and presented three death peaks within a week. Fr-BMT decreased the BMC transplanted but increased the accumulatively homed BMC and enhanced the survival rates of recipients.
Conclusions: Fr-BMT is able to enhance hematopoietic cell homing and engraftment, and this method might prove to be a solution to the previous clinical problem that a single unit of umbilical cord blood is not sufficient for engraftment in adults.