Murine allogeneic in vivo stem cell homing^,

Abstract

Stem cell homing has been studied in syngeneic models and appears to be rapid (<1 h) and dependent on cellular adhesion and migration factors. We utilized a full H2-mismatched transplantation model to determine the basics of allogeneic homing. C57BL/6J Lin-Sca-1+ cells were labeled with CFSE and injected in non-myeloablated BALB/c mice. Fluorescent cell detection was via high-speed FACS analysis. Alternatively, B6.SJL whole bone marrow cells were injected in lethally irradiated BALB/ c mice (10 Gy). One, 3, 6, and 24 h after transplant, marrow was harvested and cells were either plated for high proliferative potential colony-forming cell (HPP-CFC) assay or secondarily injected into myeloablated (8 Gy) C57BL/6J mice using 10% competing C57BL/6J marrow. Chimerism was evaluated at 8 weeks. CFSE+ cells were detected in the bone marrow 1, 3, and 6 h after injection. The numbers were moderately lower when compared to syngeneic homing possibly due to strain effect. Conversely, utilizing a surrogate or secondary assay, we observed a decline of secondary engraftment of harvested cells over time, but not of HPP-CFC. Combining experiments and normalizing the 1-h time point to 100% (to allow comparison), we observed a mean relative engraftment of 87 ± 29%, 72 ± 21%, 84 ± 35% of the 1 h level at 3, 6, and 24 h respectively. HPP-CFC assay showed no significant variation as a homing surrogate over 1-6 h. These data indicate a rapid homing into allogeneic recipients with a plateau at 1 h. The decline of secondary engraftability over time may indicate a phenotype alteration of homed cells.Hematopoetic stem cells (HSC) are defined by their capacity to fully reconstitute marrow of lethally irradiated hosts and give rise to all marrow-derived hematopoietic elements. Stem cell transplantation is a clinical approach used to restore defective hematopoiesis due either to highdose chemoradiotherapy or to intrinsic marrow diseases. In this process, intravenously infused stem cells rapidly find their way to specific periendosteal location in the marrow-termed niches. The totality of this process defines homing . Using syngeneic inbred mice, many aspects of stem cell homing have been described (Vos et al

Investigation of unmatured hematopoietic cell migration in a mouse model

“…Other studies demonstrate that HSC could be also found in bone marrow and peripheral blood 1 h after their injection [19]. However, the current work demonstrates that fluorescent labeled cells were found in spleen tissue only after 4 hours of inoculation.…”

“…Using kidney damage model it was found out that inoculated HSC were detected in kidney tissue following 24 hours of treatment [7]. Colvin et al [19] stated that after three hours of inoculation the stem cells were not found in peripheral blood. Our study revealed that hematopoietic lin -cells could stay in liver tissue for 48 hours, in spleen and paw edema at least for 72 hours.…”

FGF-23 Is a Negative Regulator of Prenatal and Postnatal Erythropoiesis

“…We petitive host HSC pool that can be easily replaced by donor HSCs (34,35). Homing efficiency was assessed 24 h post-transplantation in the bone marrow, peripheral blood, and spleen of the recipient mice.…”

Hematopoietic Recovery after Transplantation CD117+B220- (lacZ+) Bone Marrow Cells in Lethally Irradiated Mice

“…CFU-GM was 918.7±47.82 in the group of non-irradiated mice. There was significant increase of CFU-GM in the spleen of non-irradiated mice -29.8±19.23 CFU-GM for 10 5 The data reported of mean±SD (standard deviation of the mean)colonies of CFU-GM (granulocyte-macrophage colonyforming unit cells). * Differences in the hematopoietic recovery of the total number colony CFU-GMx10 5 MNC (mononuclear cells) is significant (p < 0.01).…”

“…It means that the process of bone marrow repair and hematopoiesis reconstitution is also associated with more extensive reparation processes and with issues such as homing of transplated cells, much discussed at present (15,5). Our experiments were aimed at hematopoetic rescue of transplanted CD117 + (lacZ + ) cells sorted from bone marrow after whole-body (WB) lethally irradiated mice.…”